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Tymko MM, Drapeau A, Vieira-Coelho MA, Labrecque L, Imhoff S, Coombs GB, Langevin S, Fortin M, Châteauvert N, Ainslie PN, Brassard P. Acute isometric and dynamic exercise do not alter cerebral sympathetic nerve activity in healthy humans. J Cereb Blood Flow Metab 2024:271678X241248228. [PMID: 38613232 DOI: 10.1177/0271678x241248228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 04/14/2024]
Abstract
The impact of physiological stressors on cerebral sympathetic nervous activity (SNA) remains controversial. We hypothesized that cerebral noradrenaline (NA) spillover, an index of cerebral SNA, would not change during both submaximal isometric handgrip (HG) exercise followed by a post-exercise circulatory occlusion (PECO), and supine dynamic cycling exercise. Twelve healthy participants (5 females) underwent simultaneous blood sampling from the right radial artery and right internal jugular vein. Right internal jugular vein blood flow was measured using Duplex ultrasound, and tritiated NA was infused through the participants' right superficial forearm vein. Heart rate was recorded via electrocardiogram and blood pressure was monitored using the right radial artery. Total NA spillover increased during HG (P = 0.049), PECO (P = 0.006), and moderate cycling exercise (P = 0.03) compared to rest. Cerebral NA spillover remained unchanged during isometric HG exercise (P = 0.36), PECO after the isometric HG exercise (P = 0.45), and during moderate cycling exercise (P = 0.94) compared to rest. These results indicate that transient increases in blood pressure during acute exercise involving both small and large muscle mass do not engage cerebral SNA in healthy humans. Our findings suggest that cerebral SNA may be non-obligatory for exercise-related cerebrovascular adjustments.
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Affiliation(s)
- Michael M Tymko
- Integrative Cerebrovascular and Environmental Physiology SB Laboratory, Department of Human Health and Nutritional Sciences, College of Biological Science, University of Guelph, Guelph, Canada
- Department of Medicine, Faculty of Medicine, University of British Columbia, Vancouver, Canada
| | - Audrey Drapeau
- Department of Kinesiology, Faculty of Medicine, Université Laval, Québec, Canada
- Institut universitaire de cardiologie et de pneumologie de Québec-Université Laval, Québec, Canada
| | - Maria Augusta Vieira-Coelho
- Department of Biomedicine, Pharmacology and Therapeutics Unit, Faculty of Medicine, University of Porto, Portugal
- Department of Psychiatry and Mental Health, University Hospital Center of São João, Porto, Portugal
| | - Lawrence Labrecque
- Department of Kinesiology, Faculty of Medicine, Université Laval, Québec, Canada
- Institut universitaire de cardiologie et de pneumologie de Québec-Université Laval, Québec, Canada
| | - Sarah Imhoff
- Department of Kinesiology, Faculty of Medicine, Université Laval, Québec, Canada
- Institut universitaire de cardiologie et de pneumologie de Québec-Université Laval, Québec, Canada
| | - Geoff B Coombs
- Department of Kinesiology, Faculty of Science, McMaster University, Hamilton, Canada
| | - Stephan Langevin
- Institut universitaire de cardiologie et de pneumologie de Québec-Université Laval, Québec, Canada
| | - Marc Fortin
- Institut universitaire de cardiologie et de pneumologie de Québec-Université Laval, Québec, Canada
| | - Nathalie Châteauvert
- Institut universitaire de cardiologie et de pneumologie de Québec-Université Laval, Québec, Canada
| | - Philip N Ainslie
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan, Kelowna, Canada
| | - Patrice Brassard
- Department of Kinesiology, Faculty of Medicine, Université Laval, Québec, Canada
- Institut universitaire de cardiologie et de pneumologie de Québec-Université Laval, Québec, Canada
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Patrician A, Anholm JD, Ainslie PN. A narrative review of periodic breathing during sleep at high altitude: From acclimatizing lowlanders to adapted highlanders. J Physiol 2024. [PMID: 38534039 DOI: 10.1113/jp285427] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2023] [Accepted: 02/15/2024] [Indexed: 03/28/2024] Open
Abstract
Periodic breathing during sleep at high altitude is almost universal among sojourners. Here, in the context of acclimatization and adaptation, we provide a contemporary review on periodic breathing at high altitude, and explore whether this is an adaptive or maladaptive process. The mechanism(s), prevalence and role of periodic breathing in acclimatized lowlanders at high altitude are contrasted with the available data from adapted indigenous populations (e.g. Andean and Tibetan highlanders). It is concluded that (1) periodic breathing persists with acclimatization in lowlanders and the severity is proportional to sleeping altitude; (2) periodic breathing does not seem to coalesce with poor sleep quality such that, with acclimatization, there appears to be a lengthening of cycle length and minimal impact on the average sleeping oxygen saturation; and (3) high altitude adapted highlanders appear to demonstrate a blunting of periodic breathing, compared to lowlanders, comprising a feature that withstands the negative influences of chronic mountain sickness. These observations indicate that periodic breathing persists with high altitude acclimatization with no obvious negative consequences; however, periodic breathing is attenuated with high altitude adaptation and therefore potentially reflects an adaptive trait to this environment.
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Affiliation(s)
- Alexander Patrician
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan, Kelowna, BC, Canada
| | - James D Anholm
- Department of Medicine, Division of Pulmonary and Critical Care, Loma Linda University School of Medicine, Loma Linda, CA, USA
| | - Philip N Ainslie
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan, Kelowna, BC, Canada
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Douglas AJM, Talbot JS, Perkins D, Dawkins TG, Oliver JL, Lloyd RS, Ainslie PN, McManus A, Pugh CJA, Lord RN, Stembridge M. The influence of maturation and sex on intracranial blood velocities during exercise in children. J Appl Physiol (1985) 2024; 136:451-459. [PMID: 38126090 DOI: 10.1152/japplphysiol.00478.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Accepted: 12/15/2023] [Indexed: 12/23/2023] Open
Abstract
Cerebral blood velocity (CBv) increases in response to moderate exercise in humans, but the magnitude of change is smaller in children compared with postpubertal adolescents and adults. Whether sex differences exist in the anterior or posterior CBv response to exercise across pubertal development remains to be determined. We assessed middle cerebral artery (MCAv) and posterior cerebral artery (PCAv) blood velocity via transcranial Doppler in 38 prepubertal (18 males) and 48 postpubertal (23 males) with cerebrovascular and cardiorespiratory measures compared at baseline and ventilatory threshold. At baseline, MCAv was higher in both sexes pre- versus postpuberty. Females demonstrated a greater MCAv (P < 0.001) than their male counterparts (prepubertal females; 78 ± 11 cm·s-1 vs. prepubertal males; 72 ± 8 cm·s-1, and postpubertal females; 68 ± 10 cm·s-1 vs. postpubertal males; 62 ± 7 cm·s-1). During exercise, MCAv remained higher in postpubertal females versus males (81 ± 15 cm·s-1 vs. 73 ± 11 cm·s-1), but there were no differences in prepuberty. The relative increase in PCAv was greater in post- versus prepubertal females (51 ± 9 cm·s-1 vs. 45 ± 11 cm·s-1; P = 0.032) but was similar in males and females. Our findings suggest that biological sex alters anterior cerebral blood velocities at rest in both pre- and postpubertal youth, but the response to submaximal exercise is only influenced by sex postpuberty.NEW & NOTEWORTHY Cerebral blood velocity (CBv) in the anterior circulation was higher in females compared with males irrespective of maturational stage, but not in the posterior circulation. In response to exercise, females demonstrated a greater CBv compared with males, especially post-peak height velocity (post-PHV) where the CBv response to exercise was more pronounced. Our findings suggest that both CBv at rest and in response to acute submaximal exercise are altered by biological sex in a maturity-dependent manner.
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Affiliation(s)
- Andrew J M Douglas
- Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, United Kingdom
- Centre for Health, Activity and Wellbeing Research, Cardiff Metropolitan University, Cardiff, United Kingdom
| | - Jack S Talbot
- Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, United Kingdom
- Centre for Health, Activity and Wellbeing Research, Cardiff Metropolitan University, Cardiff, United Kingdom
| | - Dean Perkins
- Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, United Kingdom
- Department of Sport Science, University of Innsbruck, Innsbruck, Austria
| | - Tony G Dawkins
- Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, United Kingdom
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, British Columbia, Canada
| | - Jon L Oliver
- Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, United Kingdom
- Youth Physical Development Centre, Cardiff Metropolitan University, Cardiff, United Kingdom
- Sports Performance Research Institute New Zealandy, AUT University, Auckland, New Zealand
| | - Rhodri S Lloyd
- Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, United Kingdom
- Youth Physical Development Centre, Cardiff Metropolitan University, Cardiff, United Kingdom
- Sports Performance Research Institute New Zealandy, AUT University, Auckland, New Zealand
- Centre for Sport Science and Human Performance, Waikato Institute of Technology, Waikato, New Zealand
| | - Philip N Ainslie
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, British Columbia, Canada
| | - Ali McManus
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, British Columbia, Canada
| | - Christopher J A Pugh
- Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, United Kingdom
- Centre for Health, Activity and Wellbeing Research, Cardiff Metropolitan University, Cardiff, United Kingdom
| | - Rachel N Lord
- Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, United Kingdom
- Centre for Health, Activity and Wellbeing Research, Cardiff Metropolitan University, Cardiff, United Kingdom
| | - Mike Stembridge
- Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, United Kingdom
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Steele AR, Howe CA, Gibbons TD, Foster K, Williams AM, Caldwell HG, Brewster LM, Duffy J, Monteleone JA, Subedi P, Anholm JD, Stembridge M, Ainslie PN, Tremblay JC. Hemorheological, cardiorespiratory, and cerebrovascular effects of pentoxifylline following acclimatization to 3,800 m. Am J Physiol Heart Circ Physiol 2024; 326:H705-H714. [PMID: 38241007 DOI: 10.1152/ajpheart.00783.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Revised: 01/16/2024] [Accepted: 01/17/2024] [Indexed: 02/23/2024]
Abstract
Pentoxifylline is a nonselective phosphodiesterase inhibitor used for the treatment of peripheral artery disease. Pentoxifylline acts through cyclic adenosine monophosphate, thereby enhancing red blood cell deformability, causing vasodilation and decreasing inflammation, and potentially stimulating ventilation. We conducted a double-blind, placebo-controlled, crossover, counter-balanced study to test the hypothesis that pentoxifylline could lower blood viscosity, enhance cerebral blood flow, and decrease pulmonary artery pressure in lowlanders following 11-14 days at 3,800 m. Participants (6 males/10 females; age, 27 ± 4 yr old) received either a placebo or 400 mg of pentoxifylline orally the night before and again 2 h before testing. We assessed arterial blood gases, venous hemorheology (blood viscosity, red blood cell deformability, and aggregation), and inflammation (TNF-α) in room air (end-tidal oxygen partial pressure, ∼52 mmHg). Global cerebral blood flow (gCBF), ventilation, and pulmonary artery systolic pressure (PASP) were measured in room air and again after 8-10 min of isocapnic hypoxia (end-tidal oxygen partial pressure, 40 mmHg). Pentoxifylline did not alter arterial blood gases, TNF-α, or hemorheology compared with placebo. Pentoxifylline did not affect gCBF or ventilation during room air or isocapnic hypoxia compared with placebo. However, in females, PASP was reduced with pentoxifylline during room air (placebo, 19 ± 3; pentoxifylline, 16 ± 3 mmHg; P = 0.021) and isocapnic hypoxia (placebo, 22 ± 5; pentoxifylline, 20 ± 4 mmHg; P = 0.029), but not in males. Acute pentoxifylline administration in lowlanders at 3,800 m had no impact on arterial blood gases, hemorheology, inflammation, gCBF, or ventilation. Unexpectedly, however, pentoxifylline reduced PASP in female participants, indicating a potential effect of sex on the pulmonary vascular responses to pentoxifylline.NEW & NOTEWORTHY We conducted a double-blind, placebo-controlled study on the rheological, cardiorespiratory and cerebrovascular effects of acute pentoxifylline in healthy lowlanders after 11-14 days at 3,800 m. Although red blood cell deformability was reduced and blood viscosity increased compared with low altitude, acute pentoxifylline administration had no impact on arterial blood gases, hemorheology, inflammation, cerebral blood flow, or ventilation. Pentoxifylline decreased pulmonary artery systolic pressure in female, but not male, participants.
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Affiliation(s)
- Andrew R Steele
- Centre for Heart, Lung & Vascular Health, School of Health and Exercise Sciences, University of British Columbia-Okanagan, Kelowna, British Columbia, Canada
| | - Connor A Howe
- Centre for Heart, Lung & Vascular Health, School of Health and Exercise Sciences, University of British Columbia-Okanagan, Kelowna, British Columbia, Canada
| | - Travis D Gibbons
- Centre for Heart, Lung & Vascular Health, School of Health and Exercise Sciences, University of British Columbia-Okanagan, Kelowna, British Columbia, Canada
- Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona, United States
| | - Katharine Foster
- Pulmonary and Critical Care, Veterans Affairs Loma Linda Healthcare System, Loma Linda, California, United States
- Department of Medicine, Loma Linda University School of Medicine, Loma Linda, California, United States
| | - Alexandra M Williams
- Department of Cellular & Physiological Sciences, Faculty of Medicine, University of British Columbia, Kelowna, British Columbia, Canada
| | - Hannah G Caldwell
- Centre for Heart, Lung & Vascular Health, School of Health and Exercise Sciences, University of British Columbia-Okanagan, Kelowna, British Columbia, Canada
| | - L Madden Brewster
- Centre for Heart, Lung & Vascular Health, School of Health and Exercise Sciences, University of British Columbia-Okanagan, Kelowna, British Columbia, Canada
| | - Jennifer Duffy
- Centre for Heart, Lung & Vascular Health, School of Health and Exercise Sciences, University of British Columbia-Okanagan, Kelowna, British Columbia, Canada
| | - Justin A Monteleone
- Centre for Heart, Lung & Vascular Health, School of Health and Exercise Sciences, University of British Columbia-Okanagan, Kelowna, British Columbia, Canada
| | - Prajan Subedi
- Pulmonary and Critical Care, Veterans Affairs Loma Linda Healthcare System, Loma Linda, California, United States
- Department of Medicine, Loma Linda University School of Medicine, Loma Linda, California, United States
| | - James D Anholm
- Pulmonary and Critical Care, Veterans Affairs Loma Linda Healthcare System, Loma Linda, California, United States
- Department of Medicine, Loma Linda University School of Medicine, Loma Linda, California, United States
| | - Mike Stembridge
- Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, United Kingdom
| | - Philip N Ainslie
- Centre for Heart, Lung & Vascular Health, School of Health and Exercise Sciences, University of British Columbia-Okanagan, Kelowna, British Columbia, Canada
| | - Joshua C Tremblay
- Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, United Kingdom
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Green DJ, Silva GO, Smith KJ, Maslen BA, Cox KL, Lautenschlager NT, Pestell CF, Ainslie PN, Haynes A, Naylor LH. Impact of Water- and Land-Based Exercise Training on Risk Factors and Vascular Function in Middle-Aged and Older Men and Women. Med Sci Sports Exerc 2024; 56:230-237. [PMID: 37710393 DOI: 10.1249/mss.0000000000003302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/16/2023]
Abstract
INTRODUCTION Exercise improves vascular function, but it is unclear whether benefits are mediated by traditional cardiovascular risk factors or whether sex differences in training effects exist in older adults. We hypothesized that exercise would improve cardiovascular risk factors, that males and females would benefit similarly, and that improvements in risk factors would correlate with changes in vascular function. METHODS Seventy-two healthy middle-aged/older adults (age, 62 ± 7 yr; 26%♂) were randomized to a land-walking ( n = 23), water-walking ( n = 25), or a nonexercise control group (C; n = 23). The exercise groups undertook supervised and monitored training three times a week for 50 min per session, across 24 wk. Blood pressure, body composition (dual x-ray absorptiometry), blood lipids and glucose, and flow-mediated brachial artery dilation were assessed in all participants at weeks 0 and 24. To maximize power for sex differences and correlation analyses, we pooled the training groups (land-walking + water-walking). RESULTS Training prevented increases in LDL and total cholesterol/HDL ratio observed in the nonexercise control group. No group by time interactions were observed for other risk factors. Sex differences in training effects existed for visceral fat (-187 ± 189 g♂ vs -15 ± 161 g♀; P = 0.006) and lean mass (-352 ± 1045 g♂ vs 601 ± 1178 g♀; P = 0.008). Improvement in flow-mediated brachial artery dilation was correlated with decreased waist girth ( r = -0.450, P = 0.036), but not with other risk factors. CONCLUSIONS Exercise training prevented deterioration in lipid levels, whereas sex differences existed for body composition changes with training. Improvement in vascular function was not dependent on changes in risk factors in middle-aged/older adults, suggesting that artery health may be dependent on other exercise-related stimuli.
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Affiliation(s)
- Daniel J Green
- School of Human Sciences (Exercise and Sport Science), The University of Western Australia, Perth, WA, AUSTRALIA
| | | | | | - Barbara A Maslen
- School of Human Sciences (Exercise and Sport Science), The University of Western Australia, Perth, WA, AUSTRALIA
| | | | | | - Carmela F Pestell
- School of Psychological Science, University of Western Australia, Perth, WA, AUSTRALIA
| | - Philip N Ainslie
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Science, University of British Columbia, Kelowna, British Columbia, CANADA
| | - Andrew Haynes
- School of Human Sciences (Exercise and Sport Science), The University of Western Australia, Perth, WA, AUSTRALIA
| | - Louise H Naylor
- School of Human Sciences (Exercise and Sport Science), The University of Western Australia, Perth, WA, AUSTRALIA
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Gibbons TD, Caldwell HG, Islam H, Duffy J, MacLeod DB, Ainslie PN. Intense exercise at high altitude causes platelet loss across the brain in humans. J Physiol 2024. [PMID: 38180146 DOI: 10.1113/jp285603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Accepted: 12/19/2023] [Indexed: 01/06/2024] Open
Abstract
Platelets are known primarily for their role in blood clotting; however, it is becoming clear that they play diverse roles beyond that of haemostasis. Exercise has been shown to activate platelets and stimulate neurogenesis, neuroplasticity and improve cognitive function, highlighting a potentially powerful link between platelet function and brain health. Despite this clear link between platelets and the brain, very little is known about the behaviour of platelets through the cerebral circulation in humans. We examined platelet concentration across the brain in exercising humans at sea level (340 m) and high altitude (6-8 days at 3800 m; a stimulus known to modify platelet function). During intense exercise at sea level, platelet concentration increased similarly by 27 ± 17% in the arterial and internal jugular venous circulations (exercise: P < 0.001, interaction: P = 0.262), indicating no uptake or release of platelets into/from the brain. At high altitude, resting platelet concentrations were similar to sea level values in both the arterial and jugular venous circulations (P = 0.590); however, intense exercise at high altitude caused a 31 ± 35% decrease in platelet concentration across the brain (P = 0.016). This divergent response across the brain was not observed in any other haematological or metabolic variables. These data highlight a unique situation where the combination of intense exercise and high altitude hypoxia cause a decrease in platelet concentration across the cerebral circulation. The physiological implications and mechanisms that might influence platelet function across the brain during exercise at high altitude remain to be established. KEY POINTS: Platelets are known primarily for their role in blood clotting; however, it is becoming clear that they play diverse roles beyond that of haemostasis. Exercise has been shown to activate platelets, which in turn stimulate neurogenesis, neuroplasticity and improve cognitive function, highlighting a powerful link between platelet function and brain health. At sea level, platelet concentration in blood going into and out of the brain was similar at rest, during maximal exercise and in recovery from exercise. During maximal exercise at high altitude, platelet concentration was 31% lower in the blood exiting the brain; the final destination of these platelets is unknown. The physiological implications and mechanisms that might influence platelet function across the cerebral circulation during exercise at high altitude remain to be established.
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Affiliation(s)
- Travis Dylan Gibbons
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Science, University of British Columbia - Okanagan, Kelowna, BC, Canada
- Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ, USA
| | - Hannah G Caldwell
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Science, University of British Columbia - Okanagan, Kelowna, BC, Canada
| | - Hashim Islam
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Science, University of British Columbia - Okanagan, Kelowna, BC, Canada
| | - Jennifer Duffy
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Science, University of British Columbia - Okanagan, Kelowna, BC, Canada
| | - David B MacLeod
- Department of Anesthesiology, Duke University Medical Center, Durham, NC, USA
| | - Philip N Ainslie
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Science, University of British Columbia - Okanagan, Kelowna, BC, Canada
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Talbot JS, Perkins DR, Tallon CM, Dawkins TG, Douglas AJM, Beckerleg R, Crofts A, Wright ME, Davies S, Steventon JJ, Murphy K, Lord RN, Pugh CJA, Oliver JL, Lloyd RS, Ainslie PN, McManus AM, Stembridge M. Cerebral blood flow and cerebrovascular reactivity are modified by maturational stage and exercise training status during youth. Exp Physiol 2023; 108:1500-1515. [PMID: 37742137 PMCID: PMC10988468 DOI: 10.1113/ep091279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Accepted: 09/08/2023] [Indexed: 09/25/2023]
Abstract
NEW FINDINGS What is the central question of this study? Gonadal hormones modulate cerebrovascular function while insulin-like growth factor 1 (IGF-1) facilitates exercise-mediated cerebral angiogenesis; puberty is a critical period of neurodevelopment alongside elevated gonadal hormone and IGF-1 activity: but whether exercise training across puberty enhances cerebrovascular function is unkown. What is the main finding and its importance? Cerebral blood flow is elevated in endurance trained adolescent males when compared to untrained counterparts. However, cerebrovascular reactivity to hypercapnia is faster in trained vs. untrained children, but not adolescents. Exercise-induced improvements in cerebrovascular function are attainable as early as the first decade of life. ABSTRACT Global cerebral blood flow (gCBF) and cerebrovascular reactivity to hypercapnia (CV R C O 2 ${\mathrm{CV}}{{\mathrm{R}}_{{\mathrm{C}}{{\mathrm{O}}_{\mathrm{2}}}}}$ ) are modulated by gonadal hormone activity, while insulin-like growth factor 1 facilitates exercise-mediated cerebral angiogenesis in adults. Whether critical periods of heightened hormonal and neural development during puberty represent an opportunity to further enhance gCBF andCV R C O 2 ${\mathrm{CV}}{{\mathrm{R}}_{{\mathrm{C}}{{\mathrm{O}}_{\mathrm{2}}}}}$ is currently unknown. Therefore, we used duplex ultrasound to assess gCBF andCV R C O 2 ${\mathrm{CV}}{{\mathrm{R}}_{{\mathrm{C}}{{\mathrm{O}}_{\mathrm{2}}}}}$ in n = 128 adolescents characterised as endurance-exercise trained (males: n = 30, females: n = 36) or untrained (males: n = 29, females: n = 33). Participants were further categorised as pre- (males: n = 35, females: n = 33) or post- (males: n = 24, females: n = 36) peak height velocity (PHV) to determine pubertal or 'maturity' status. Three-factor ANOVA was used to identify main and interaction effects of maturity status, biological sex and training status on gCBF andCV R C O 2 ${\mathrm{CV}}{{\mathrm{R}}_{{\mathrm{C}}{{\mathrm{O}}_{\mathrm{2}}}}}$ . Data are reported as group means (SD). Pre-PHV youth demonstrated elevated gCBF and slowerCV R C O 2 ${\mathrm{CV}}{{\mathrm{R}}_{{\mathrm{C}}{{\mathrm{O}}_{\mathrm{2}}}}}$ mean response times than post-PHV counterparts (both: P ≤ 0.001). gCBF was only elevated in post-PHV trained males when compared to untrained counterparts (634 (43) vs. 578 (46) ml min-1 ; P = 0.007). However,CV R C O 2 ${\mathrm{CV}}{{\mathrm{R}}_{{\mathrm{C}}{{\mathrm{O}}_{\mathrm{2}}}}}$ mean response time was faster in pre- (72 (20) vs. 95 (29) s; P ≤ 0.001), but not post-PHV (P = 0.721) trained youth when compared to untrained counterparts. Cardiorespiratory fitness was associated with gCBF in post-PHV youth (r2 = 0.19; P ≤ 0.001) andCV R C O 2 ${\mathrm{CV}}{{\mathrm{R}}_{{\mathrm{C}}{{\mathrm{O}}_{\mathrm{2}}}}}$ mean response time in pre-PHV youth (r2 = 0.13; P = 0.014). Higher cardiorespiratory fitness during adolescence can elevate gCBF while exercise training during childhood primes the development of cerebrovascular function, highlighting the importance of exercise training during the early stages of life in shaping the cerebrovascular phenotype.
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Affiliation(s)
- Jack S. Talbot
- Cardiff School of Sport and Health SciencesCardiff Metropolitan UniversityCardiffUK
- Centre for Health, Activity and Wellbeing ResearchCardiff Metropolitan UniversityCardiffUK
| | - Dean R. Perkins
- Department of Sport ScienceUniversity of InnsbruckInnsbruckAustria
| | - Christine M. Tallon
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise SciencesUniversity of British Columbia OkanaganKelownaCanada
| | - Tony G. Dawkins
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise SciencesUniversity of British Columbia OkanaganKelownaCanada
| | - Andrew J. M. Douglas
- Cardiff School of Sport and Health SciencesCardiff Metropolitan UniversityCardiffUK
- Centre for Health, Activity and Wellbeing ResearchCardiff Metropolitan UniversityCardiffUK
| | - Ryan Beckerleg
- Cardiff University Brain Research Imaging Centre (CUBRIC), School of Physics and AstronomyCardiff UniversityCardiffUK
| | - Andrew Crofts
- Cardiff University Brain Research Imaging Centre (CUBRIC), School of Physics and AstronomyCardiff UniversityCardiffUK
| | - Melissa E. Wright
- Cardiff University Brain Research Imaging Centre (CUBRIC), School of Physics and AstronomyCardiff UniversityCardiffUK
| | - Saajan Davies
- Cardiff University Brain Research Imaging Centre (CUBRIC), School of Physics and AstronomyCardiff UniversityCardiffUK
| | - Jessica J. Steventon
- Cardiff University Brain Research Imaging Centre (CUBRIC), School of Physics and AstronomyCardiff UniversityCardiffUK
| | - Kevin Murphy
- Cardiff University Brain Research Imaging Centre (CUBRIC), School of Physics and AstronomyCardiff UniversityCardiffUK
| | - Rachel N. Lord
- Cardiff School of Sport and Health SciencesCardiff Metropolitan UniversityCardiffUK
- Centre for Health, Activity and Wellbeing ResearchCardiff Metropolitan UniversityCardiffUK
| | - Christopher J. A. Pugh
- Cardiff School of Sport and Health SciencesCardiff Metropolitan UniversityCardiffUK
- Centre for Health, Activity and Wellbeing ResearchCardiff Metropolitan UniversityCardiffUK
| | - Jon L. Oliver
- Youth Physical Development CentreCardiff Metropolitan UniversityCardiffUK
- Sports Performance Research Institute New ZealandAUT UniversityAucklandNew Zealand
| | - Rhodri S. Lloyd
- Youth Physical Development CentreCardiff Metropolitan UniversityCardiffUK
- Sports Performance Research Institute New ZealandAUT UniversityAucklandNew Zealand
- Centre for Sport Science and Human PerformanceWaikato Institute of TechnologyWaikatoNew Zealand
| | - Philip N. Ainslie
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise SciencesUniversity of British Columbia OkanaganKelownaCanada
| | - Ali M. McManus
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise SciencesUniversity of British Columbia OkanaganKelownaCanada
| | - Mike Stembridge
- Cardiff School of Sport and Health SciencesCardiff Metropolitan UniversityCardiffUK
- Centre for Health, Activity and Wellbeing ResearchCardiff Metropolitan UniversityCardiffUK
- Youth Physical Development CentreCardiff Metropolitan UniversityCardiffUK
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8
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Parikh K, Shepley BR, Tymko MM, Hijmans JG, Hoiland RL, Desouza CA, Sekhon MS, Ainslie PN, Bain AR. Cerebral uptake of microvesicles occurs in normocapnic but not hypocapnic passive hyperthermia in young healthy male adults. J Physiol 2023; 601:5601-5616. [PMID: 37975212 DOI: 10.1113/jp285265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Accepted: 11/01/2023] [Indexed: 11/19/2023] Open
Abstract
Passive hyperthermia causes cerebral hypoperfusion primarily from heat-induced respiratory alkalosis. However, despite the cerebral hypoperfusion, it is possible that the mild alkalosis might help to attenuate cerebral inflammation. In this study, the cerebral exchange of extracellular vesicles (microvesicles), which are known to elicit pro-inflammatory responses when released in conditions of stress, were examined in hyperthermia with and without respiratory alkalosis. Ten healthy male adults were heated passively, using a warm water-perfused suit, up to core temperature + 2°C. Blood samples were taken from the radial artery and internal jugular bulb. Microvesicle concentrations were determined in platelet-poor plasma via cells expressing CD62E (activated endothelial cells), CD31+ /CD42b- (apoptotic endothelial cells), CD14 (monocytes) and CD45 (pan-leucocytes). Cerebral blood flow was measured via duplex ultrasound of the internal carotid and vertebral arteries to determine cerebral exchange kinetics. From baseline to poikilocapnic (alkalotic) hyperthermia, there was no change in microvesicle concentration from any cell origin measured (P-values all >0.05). However, when blood CO2 tension was normalized to baseline levels in hyperthermia, there was a marked increase in cerebral uptake of microvesicles expressing CD62E (P = 0.028), CD31+ /CD42b- (P = 0.003) and CD14 (P = 0.031) compared with baseline, corresponding to large increases in arterial but not jugular venous concentrations. In a subset of seven participants who underwent hypercapnia and hypocapnia in the absence of heating, there was no change in microvesicle concentrations or cerebral exchange, suggesting that hyperthermia potentiated the CO2 /pH-mediated cerebral uptake of microvesicles. These data provide insight into a potential beneficial role of respiratory alkalosis in heat stress. KEY POINTS: The hyperthermia-induced hyperventilatory response is observed in most humans, despite causing potentially harmful reductions in cerebral blood flow. We tested the hypothesis that the respiratory-induced alkalosis is associated with lower circulating microvesicle concentrations, specifically in the brain, despite the reductions in blood flow. At core temperature + 2°C with respiratory alkalosis, microvesicles derived from endothelial cells, monocytes and leucocytes were at concentrations similar to baseline in the arterial and cerebral venous circulation, with no changes in cross-brain microvesicle kinetics. However, when core temperature was increased by 2°C with CO2 /pH normalized to resting levels, there was a marked cerebral uptake of microvesicles derived from endothelial cells and monocytes. The CO2 /pH-mediated alteration in cerebral microvesicle uptake occurred only in hyperthermia. These new findings suggest that the heat-induced hyperventilatory response might serve a beneficial role by preventing potentially inflammatory microvesicle uptake in the brain.
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Affiliation(s)
- Khushali Parikh
- Faculty of Human Kinetics, Department of Kinesiology, University of Windsor, Windsor, ON, Canada
| | - Brooke R Shepley
- Faculty of Human Kinetics, Department of Kinesiology, University of Windsor, Windsor, ON, Canada
| | - Michael M Tymko
- Centre for Heart, Lung and Vascular Health, University of British Columbia, Kelowna, BC, Canada
- Department of Human Health and Nutritional Sciences, College of Biological Science, University of Guelph, Guelph, ON, Canada
| | - Jamie G Hijmans
- Department of Integrative Biology, University of Colorado Boulder, Boulder, CO, USA
| | - Ryan L Hoiland
- Centre for Heart, Lung and Vascular Health, University of British Columbia, Kelowna, BC, Canada
- Division of Critical Care Medicine, Department of Medicine, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
- Division of Neurosurgery, Department of Surgery, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
- International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, BC, Canada
- Collaborative Entity for Researching Brain Ischemia, University of British Columbia, Vancouver, BC, Canada
| | | | - Mypinder S Sekhon
- Division of Critical Care Medicine, Department of Medicine, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
- Division of Neurosurgery, Department of Surgery, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
- International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, BC, Canada
- Collaborative Entity for Researching Brain Ischemia, University of British Columbia, Vancouver, BC, Canada
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada
| | - Philip N Ainslie
- Centre for Heart, Lung and Vascular Health, University of British Columbia, Kelowna, BC, Canada
| | - Anthony R Bain
- Faculty of Human Kinetics, Department of Kinesiology, University of Windsor, Windsor, ON, Canada
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9
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Carr JMJR, Day TA, Ainslie PN, Hoiland RL. The jugular venous-to-arterial P C O 2 ${P_{{\mathrm{C}}{{\mathrm{O}}_{\mathrm{2}}}}}$ difference during rebreathing and end-tidal forcing: Relationship with cerebral perfusion. J Physiol 2023; 601:4251-4262. [PMID: 37635691 DOI: 10.1113/jp284449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Accepted: 08/11/2023] [Indexed: 08/29/2023] Open
Abstract
We examined two assumptions of the modified rebreathing technique for the assessment of the ventilatory central chemoreflex (CCR) and cerebrovascular CO2 reactivity (CVR), hypothesizing: (1) that rebreathing abolishes the gradient between the partial pressures of arterial and brain tissue CO2 [measured via the surrogate jugular venousP C O 2 ${P_{{\mathrm{C}}{{\mathrm{O}}_{\mathrm{2}}}}}$ and arterialP C O 2 ${P_{{\mathrm{C}}{{\mathrm{O}}_{\mathrm{2}}}}}$ difference (Pjv-a CO2 )] and (2) rebreathing eliminates the capacity of CVR to influence the Pjv-a CO2 difference, and thus affect CCR sensitivity. We also evaluated these variables during two separate dynamic end-tidal forcing (ETF) protocols (termed: ETF-1 and ETF-2), another method of assessing CCR sensitivity and CVR. Healthy participants were included in the rebreathing (n = 9), ETF-1 (n = 11) and ETF-2 (n = 10) protocols and underwent radial artery and internal jugular vein (advanced to jugular bulb) catheterization to collect blood samples. Transcranial Doppler ultrasound was used to measure middle cerebral artery blood velocity (MCAv). The Pjv-a CO2 difference was not abolished during rebreathing (6.2 ± 2.6 mmHg; P < 0.001), ETF-1 (9.3 ± 1.5 mmHg; P < 0.001) or ETF-2 (8.6 ± 1.4 mmHg; P < 0.001). The Pjv-a CO2 difference did not change during the rebreathing protocol (-0.1 ± 1.2 mmHg; P = 0.83), but was reduced during the ETF-1 (-3.9 ± 1.1 mmHg; P < 0.001) and ETF-2 (-3.4 ± 1.2 mmHg; P = 0.001) protocols. Overall, increases in MCAv were associated with reductions in the Pjv-a CO2 difference during ETF (-0.095 ± 0.089 mmHg cm-1 s-1 ; P = 0.001) but not during rebreathing (-0.028 ± 0.045 mmHg · cm-1 · s-1 ; P = 0.067). These findings suggest that, although the Pjv-a CO2 is not abolished during any chemoreflex assessment technique, hyperoxic hypercapnic rebreathing is probably more appropriate to assess CCR sensitivity independent of cerebrovascular reactivity to CO2 . KEY POINTS: Modified rebreathing is a technique used to assess the ventilatory central chemoreflex and is based on the premise that the rebreathing method eliminates the difference between arterial and brain tissueP C O 2 ${P_{{\mathrm{C}}{{\mathrm{O}}_{\mathrm{2}}}}}$ . Therefore, rebreathing is assumed to isolate the ventilatory response to central chemoreflex stimulation from the influence of cerebral blood flow. We assessed these assumptions by measuring arterial and jugular venous bulbP C O 2 ${P_{{\mathrm{C}}{{\mathrm{O}}_{\mathrm{2}}}}}$ and middle cerebral artery blood velocity during modified rebreathing and compared these data against data from another test of the ventilatory central chemoreflex using hypercapnic dynamic end-tidal forcing. The difference between arterial and jugular venous bulbP C O 2 ${P_{{\mathrm{C}}{{\mathrm{O}}_{\mathrm{2}}}}}$ remained present during both rebreathing and end-tidal forcing tests, whereas middle cerebral artery blood velocity was associated with theP C O 2 ${P_{{\mathrm{C}}{{\mathrm{O}}_{\mathrm{2}}}}}$ difference during end-tidal forcing but not rebreathing. These findings offer substantiating evidence that clarifies and refines the assumptions of modified rebreathing tests, enhancing interpretation of future findings.
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Affiliation(s)
- Jay M J R Carr
- Centre for Heart, Lung and Vascular Health, University of British Columbia Okanagan, Kelowna, BC, Canada
| | - Trevor A Day
- Department of Biology, Faculty of Science and Technology, Mount Royal University, Calgary, AB, Canada
| | - Philip N Ainslie
- Centre for Heart, Lung and Vascular Health, University of British Columbia Okanagan, Kelowna, BC, Canada
| | - Ryan L Hoiland
- Centre for Heart, Lung and Vascular Health, University of British Columbia Okanagan, Kelowna, BC, Canada
- Department of Anesthesiology, Pharmacology and Therapeutics, Vancouver General Hospital, University of British Columbia, Vancouver, BC, Canada
- Department of Cellular and Physiological Sciences, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
- International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, BC, Canada
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10
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Brewster LM, Bain AR, Garcia VP, DeSouza NM, Tymko MM, Greiner JJ, Ainslie PN. Global REACH 2018: High Altitude-Related Circulating Extracellular Microvesicles Promote a Proinflammatory Endothelial Phenotype In Vitro. High Alt Med Biol 2023; 24:223-229. [PMID: 37504958 DOI: 10.1089/ham.2023.0013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/29/2023] Open
Abstract
Brewster, L. Madden, Anthony R. Bain, Vinicius P. Garcia, Noah M. DeSouza, Michael M. Tymko, Jared J. Greiner, and Philip N. Ainslie. Global REACH 2018: high altitude-related circulating extracellular microvesicles promote a proinflammatory endothelial phenotype in vitro. High Alt Med Biol. 24:223-229, 2023. Introduction: Ascent to high altitude (HA) can induce vascular dysfunction by promoting a proinflammatory endothelial phenotype. Circulating microvesicles (MVs) can mediate the vascular endothelium and inflammation. It is unclear whether HA-related MVs are associated with endothelial inflammation. Objectives: We tested the hypothesis that MVs derived from ascent to HA induce a proinflammatory endothelial phenotype. Methods: Ten healthy adults (8 M/2 F; age: 28 ± 2 years) residing at sea level (SL) were studied before and 4-6 days after rapid ascent to HA (4,300 m). MVs were isolated and enumerated from plasma by centrifugation and flow cytometry. Human umbilical vein endothelial cells were treated with MVs collected from each subject at SL (MV-SL) and at HA (MV-HA). Results: Circulating MV number significantly increased at HA (26,637 ± 3,315 vs. 19,388 ± 1,699). Although intracellular expression of total nuclear factor kappa beta (NF-κB; 83.4 ± 6.7 arbitrary units [AU] vs. 90.2 ± 6.9 AU) was not affected, MV-HA resulted in ∼55% higher (p < 0.05) active NF-κB (129.6 ± 19.8 AU vs. 90.7 ± 10.5 AU) expression compared with MV-SL. In addition, MV-HA induced higher interleukin (IL)-6 (63.9 ± 3.9 pg/ml vs. 53.3 ± 3.6 pg/ml) and IL-8 (140.2 ± 3.6 pg/ml vs. 120.7 ± 3.8 pg/ml) release compared with MV-SL, which was blunted with NF-κB blockade. Conclusions: Circulating extracellular MVs increase at HA and induce endothelial inflammation, potentially contributing to altitude-related vascular dysfunction.
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Affiliation(s)
- L Madden Brewster
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, Colorado, USA
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, Faculty of Health and Social Development, University of British Columbia Okanagan, Kelowna, British Columbia, Canada
| | - Anthony R Bain
- Department of Kinesiology, University of Windsor, Windsor, Ontario, Canada
| | - Vinicius P Garcia
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, Colorado, USA
| | - Noah M DeSouza
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, Colorado, USA
| | - Michael M Tymko
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, Faculty of Health and Social Development, University of British Columbia Okanagan, Kelowna, British Columbia, Canada
| | - Jared J Greiner
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, Colorado, USA
| | - Philip N Ainslie
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, Faculty of Health and Social Development, University of British Columbia Okanagan, Kelowna, British Columbia, Canada
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11
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Halsey LG, Careau V, Ainslie PN, Alemán-Mateo H, Andersen LF, Anderson LJ, Arab L, Baddou I, Bandini L, Bedu-Addo K, Blaak EE, Blanc S, Bonomi AG, Bouten CVC, Bovet P, Brage S, Buchowski MS, Butte NF, Camps SG, Casper R, Close GL, Colbert LH, Cooper JA, Cooper R, Dabare P, Das SK, Davies PSW, Deb S, Nyström CD, Dietz W, Dugas LR, Eaton S, Ekelund U, Hamdouchi AE, Entringer S, Forrester T, Fudge BW, Gillingham M, Goris AH, Gurven M, Haisma H, Hambly C, Hoffman DJ, Hoos MB, Hu S, Joonas N, Joosen A, Katzmarzyk P, Kempen KP, Kimura M, Kraus WE, Kriengsinyos W, Kuriyan R, Kushner RF, Lambert EV, Lanerolle P, Larsson CL, Lessan N, Löf M, Martin CK, Matsiko E, Meijer GA, Morehen JC, Morton JP, Must A, Neuhouser M, Nicklas TA, Ojiambo RM, Pietilainen KH, Pitsiladis YP, Plange-Rhule J, Plasqui G, Prentice RL, Rabinovich R, Racette SB, Raichen DA, Ravussin E, Redman L, Reilly JJ, Reynolds RM, Roberts S, Samaranayake D, Sardinha LB, Schuit AJ, Silva AM, Sinha S, Sjödin AM, Stice E, Stunkard A, Urlacher SS, Valencia ME, Valenti G, van Etten LM, Van Mil EA, Verbunt JA, Wells JCK, Wilson G, Wood B, Yoshida T, Zhang X, Murphy-Alford A, Loechl C, Luke A, Pontzer H, Rood J, Sagayama H, Westerterp KR, Wong WW, Yamada Y, Speakman JR. Greater male variability in daily energy expenditure develops through puberty. Biol Lett 2023; 19:20230152. [PMID: 37727077 PMCID: PMC10509569 DOI: 10.1098/rsbl.2023.0152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Accepted: 08/31/2023] [Indexed: 09/21/2023] Open
Abstract
There is considerably greater variation in metabolic rates between men than between women, in terms of basal, activity and total (daily) energy expenditure (EE). One possible explanation is that EE is associated with male sexual characteristics (which are known to vary more than other traits) such as musculature and athletic capacity. Such traits might be predicted to be most prominent during periods of adolescence and young adulthood, when sexual behaviour develops and peaks. We tested this hypothesis on a large dataset by comparing the amount of male variation and female variation in total EE, activity EE and basal EE, at different life stages, along with several morphological traits: height, fat free mass and fat mass. Total EE, and to some degree also activity EE, exhibit considerable greater male variation (GMV) in young adults, and then a decreasing GMV in progressively older individuals. Arguably, basal EE, and also morphometrics, do not exhibit this pattern. These findings suggest that single male sexual characteristics may not exhibit peak GMV in young adulthood, however total and perhaps also activity EE, associated with many morphological and physiological traits combined, do exhibit GMV most prominently during the reproductive life stages.
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Affiliation(s)
- Lewis G. Halsey
- School of Life and Health Sciences, University of Roehampton, London SW15 4JD, UK
| | - Vincent Careau
- Department of Biology, University of Ottawa, Ottawa, Ontario, Canada
| | - Philip N. Ainslie
- Research Institute for Sport & Exercise Sciences, Liverpool John Moores University, Liverpool, L3 3AF, UK
| | - Heliodoro Alemán-Mateo
- Coordinación de Nutrición, Centro de Investigación en Alimentación y Desarrollo (CIAD), A.C., Carretera Gustavo Enrique Astiazarán Rosas, No. 46, Col. La Victoria, C.P. 83304, Hermosillo, Sonora, México
| | - Lene F. Andersen
- Department of Nutrition, Institute of Basic Medical Sciences, University of Oslo, 0317 Oslo, Norway
| | - Liam J. Anderson
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, B15 2TT, UK
| | - Leonore Arab
- David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - Issad Baddou
- Unité Mixte de Recherche en Nutrition et Alimentation, CNESTEN-Université Ibn Tofail, Rabat, PC.10100, Morocco
| | - Linda Bandini
- University of Massachusetts Chan Medical School, Worcester, MA, USA
| | - Kweku Bedu-Addo
- Department of Physiology, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Ellen E. Blaak
- Department of Human Biology, Nutrition and Translational Research in Metabolism (NUTRIM), Maastricht University Medical Centre, Maastricht, 6200 MD, Netherlands
| | - Stephane Blanc
- Institut Pluridisciplinaire Hubert Curien, CNRS Université de Strasbourg, Strasbourg, France
| | | | - Carlijn V. C. Bouten
- Department of Biomedical Engineering and Institute for Complex Molecular Systems, Eindhoven Unversity of Technology, Eindhoven, The Netherlands
| | - Pascal Bovet
- University Center for primary care and public health (Unisante), 1012 Lausanne, Switzerland
| | - Soren Brage
- MRC Epidemiology Unit, University of Cambridge, Cambridge, UK
| | - Maciej S. Buchowski
- Division of Gastroenterology, Hepatology and Nutrition, Department of Medicine, Vanderbilt University, Nashville, TN, USA
| | - Nancy F. Butte
- Department of Pediatrics, Baylor College of Medicine, USDA/ARS Children's Nutrition Research Center, Houston, TX, 77030, USA
| | - Stephan G. Camps
- imec within OnePlanet Research Center, 6708 WE, Wageningen, The Netherlands
| | - Regina Casper
- Stanford University School of Medicine, Department of Psychiatry, Stanford, CA 94305, USA
| | - Graeme L. Close
- Research Institute for Sport & Exercise Sciences, Liverpool John Moores University, Liverpool, L3 3AF, UK
| | | | | | - Richard Cooper
- Department of Public Health Sciences, Parkinson School of Health Sciences and Public Health, Loyola University Chicago, Maywood, IL 60153, USA
| | - Prasangi Dabare
- Department of Physiotherapy, Faculty of Allied Health Sciences, General Sir John Kotelawala Defence University, Sri Lanka
| | - Sai Krupa Das
- Jean Mayer USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA, 02111, USA
| | - Peter S. W. Davies
- Child Health Research Centre, Level 6 Centre for Children's Health Research, University of Queensland, 62 Graham Street, South Brisbane, Queensland, 4101, Australia
| | - Sanjoy Deb
- Centre for Nutraceuticals, School of Life Sciences, University of Westminster, London, UK
- Department of Circulation and Medical Imaging, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, Trondheim, Norway
| | | | | | - Lara R. Dugas
- Department of Public Health Sciences, Parkinson School of Health Sciences and Public Health, Loyola University Chicago, Maywood, IL 60153, USA
- Division of Epidemiology and Biostatistics, School of Public Health, University of Cape Town, Cape Town, South Africa
| | - Simon Eaton
- UCL Great Ormond Street Institute of Child Health, London, WC1N 1EH, UK
| | - Ulf Ekelund
- Department of Sport Medicine, Norwegian School of Sport Sciences, PO Box 4014, 0806 Ulleval Stadion, Oslo, Norway
| | - Asmaa El Hamdouchi
- Unité Mixte de Recherche en Nutrition et Alimentation, CNESTEN-Université Ibn Tofail, Rabat, PC.10100, Morocco
| | - Sonja Entringer
- Charité – Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health (BIH), Institute of Medical Psychology, Berlin, Germany
- University of California Irvine, Irvine, CA, USA
| | - Terrence Forrester
- Solutions for Developing Countries, University of the West Indies, Mona, Kingston, Jamaica
| | - Barry W. Fudge
- Physiology Department, Aspire Academy, Doha, PO Box 22287, Qatar
| | - Melanie Gillingham
- Department of Molecular and Medical Genetics, Oregon Health & Science University, Portland, OR 97239, USA
| | - Annelies H. Goris
- imec within OnePlanet Research Center, 6708 WE, Wageningen, The Netherlands
| | - Michael Gurven
- Department of Anthropology, University of California Santa Barbara, Santa Barbara, CA 93106, USA
| | - Hinke Haisma
- Population Research Centre, Faculty of Spatial Sciences, Landleven 1, 9747AD, University of Groningen, Groningen, Netherlands
| | - Catherine Hambly
- Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, AB24 2TZ, UK
| | - Daniel J. Hoffman
- Department of Nutritional Sciences, Program in International Nutrition, Rutgers University, New Brunswick, NJ 08901 USA
| | - Marije B. Hoos
- Department of Human Biology, Nutrition and Translational Research in Metabolism (NUTRIM), Maastricht University Medical Centre, Maastricht, 6200 MD, Netherlands
| | - Sumei Hu
- Institute of Genetics and development Biology, Chinese Academy of Sciences, Beichen Xi lu, Beijing, People's Republic of China
| | - Noorjehan Joonas
- Central health Laboratory, Ministry of Health and Wellness, Port Louis, 72259, Mauritius
| | - Annemiek Joosen
- imec within OnePlanet Research Center, 6708 WE, Wageningen, The Netherlands
| | - Peter Katzmarzyk
- Pennington Biomedical Research Center, Baton Rouge, LA, 70808, USA
| | - Kitty P. Kempen
- imec within OnePlanet Research Center, 6708 WE, Wageningen, The Netherlands
| | - Misaka Kimura
- Institute for Active Health, Kyoto University of Advanced Science, Kyoto, Japan
| | | | | | - Rebecca Kuriyan
- Division of Nutrition, St John's Research Institute, Bangalore, Karnataka - 560034, India
| | | | - Estelle V. Lambert
- Health through Physical Activity, Lifestyle and Sport Research Centre, Division of Exercise Science and Sports Medicine (ESSM), FIMS International Collaborating Centre of Sports Medicine, Department of Human Biology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Pulani Lanerolle
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Colombo, Colombo, Sri Lanka
| | - Christel L. Larsson
- Department of Food and Nutrition, and Sport Science, University of Gothenburg, Gothenburg SE-405 30, Sweden
| | - Nader Lessan
- Imperial College London Diabetes Centre, Abu Dhabi, United Arab Emirates
| | - Marie Löf
- Department of Circulation and Medical Imaging, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology, Trondheim, Norway
| | - Corby K. Martin
- Pennington Biomedical Research Center, Baton Rouge, LA, 70808, USA
| | - Eric Matsiko
- Department of Human Nutrition and Dietetics, University of Rwanda, Kigali, Rwanda
| | - Gerwin A. Meijer
- Department of Human Biology, Nutrition and Translational Research in Metabolism (NUTRIM), Maastricht University Medical Centre, Maastricht, 6200 MD, Netherlands
| | - James C. Morehen
- Research Institute for Sport & Exercise Sciences, Liverpool John Moores University, Liverpool, L3 3AF, UK
| | - James P. Morton
- Research Institute for Sport & Exercise Sciences, Liverpool John Moores University, Liverpool, L3 3AF, UK
| | - Aviva Must
- Tufts University School of Medicine, Boston, USA
| | - Marian Neuhouser
- Division of Public Health Sciences, Fred Hutchinson Cancer Center and School of Public Health, University of Washington, Seattle, WA, 98109, USA
| | - Theresa A. Nicklas
- Department of Pediatrics, Baylor College of Medicine, USDA/ARS Children's Nutrition Research Center, Houston, TX, 77030, USA
| | - Robert M. Ojiambo
- Moi University, Eldoret, Kenya
- University of Global Health Equity, Rwanda
| | | | | | - Jacob Plange-Rhule
- Department of Physiology, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Guy Plasqui
- Department of Nutrition and Movement Sciences, Maastricht University, 6200 MD Maastricht, The Netherlands
| | - Ross L. Prentice
- Division of Public Health Sciences, Fred Hutchinson Cancer Center and School of Public Health, University of Washington, Seattle, WA, 98109, USA
| | | | - Susan B. Racette
- College of Health Solutions, Arizona State University, Phoenix, AZ, 85004, USA
| | - David A. Raichen
- Biological Sciences and Anthropology, University of Southern California, CA, USA
| | - Eric Ravussin
- Pennington Biomedical Research Center, Baton Rouge, LA, 70808, USA
| | - Leanne Redman
- Pennington Biomedical Research Center, Baton Rouge, LA, 70808, USA
| | - John J. Reilly
- Department of Psychological Sciences and Health, University of Strathclyde, Glasgow, UK
| | - Rebecca M. Reynolds
- Centre for Cardiovascular Sciences, Queen's Medical Research Institute, University of Edinburgh, Edinburgh, EH16 4TJ, UK
| | - Susan Roberts
- Jean Mayer USDA Human Nutrition Research Center on Aging, Tufts University, Boston, MA, 02111, USA
| | - Dulani Samaranayake
- Department of Community Medicine, Faculty of Medicine, University of Colombo, Colombo, Sri Lanka
| | - Luís B. Sardinha
- Exercise and health laboratory, CIPER, Faculdade Motricidade Humana, Universidade de Lisboa, Portugal
| | - Albertine J. Schuit
- Executive Board, Tilburg University, Tilburg, Noord-Brabant, 5037 AB, The Netherlands
| | - Analiza M. Silva
- Exercise and health laboratory, CIPER, Faculdade Motricidade Humana, Universidade de Lisboa, Portugal
| | - Srishti Sinha
- Division of Nutrition, St John's Research Institute, Bangalore, Karnataka - 560034, India
| | - Anders M. Sjödin
- Department of Nutrition, Exercise and Sports, Copenhagen University, Copenhagen, Denmark
| | - Eric Stice
- PhD Department of Psychiatry and Behavioral Sciences, Stanford University, 401 Quarry Road, Stanford, CA 94305
| | - Albert Stunkard
- University of Pennsylvania Perelman School of Medicine Department of Psychiatry
| | | | - Mauro Eduardo Valencia
- Coordinación de Nutrición, Centro de Investigación en Alimentación y Desarrollo (CIAD), A.C., Carretera Gustavo Enrique Astiazarán Rosas, No. 46, Col. La Victoria, C.P. 83304, Hermosillo, Sonora, México
| | - Giulio Valenti
- imec within OnePlanet Research Center, 6708 WE, Wageningen, The Netherlands
| | - Ludo M. van Etten
- Department of Nutrition and Movement Sciences, Maastricht University, 6200 MD Maastricht, The Netherlands
| | - Edgar A. Van Mil
- Chair Youth, Food and Health, Maastricht University, 5911 BV, Venlo, and Lifestyle Medicine Center for Children, Jeroen Bosch Hospital 5223 GW `s-Hertogenbosch, The Netherlands
| | - Jeanine A. Verbunt
- imec within OnePlanet Research Center, 6708 WE, Wageningen, The Netherlands
| | - Jonathan C. K. Wells
- Population, Policy and Practice Research and Teaching Department, UCL Great Ormond Street Institute of Child Health, London, WC1N 1EH, UK
| | - George Wilson
- Research Institute for Sport & Exercise Sciences, Liverpool John Moores University, Liverpool, L3 3AF, UK
| | - Brian Wood
- University of California Los Angeles, Los Angeles, 90095, USA
- Department of Human Behavior, Ecology, and Culture, Max Planck Institute for Evolutionary Anthropology, Leipzig 04103, Germany
| | - Tsukasa Yoshida
- National Institute of Health and Nutrition, National Institutes of Biomedical Innovation, Health and Nutrition, Tokyo, Japan
| | - Xueying Zhang
- Shenzhen Key Laboratory of Metabolic Health, Center for Energy Metabolism and Reproduction, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China
| | - Alexia Murphy-Alford
- Nutritional and Health Related Environmental Studies Section, Division of Human Health, International Atomic Energy Agency, Vienna, Austria
| | - Cornelia Loechl
- Nutritional and Health Related Environmental Studies Section, Division of Human Health, International Atomic Energy Agency, Vienna, Austria
| | - Amy Luke
- Department of Public Health Sciences, Parkinson School of Health Sciences and Public Health, Loyola University Chicago, Maywood, IL 60153, USA
| | - Herman Pontzer
- Dept. of Evolutionary Anthropology, Duke University, Durham NC 27708, USA
- Duke Global Health Institute, Duke University, Durham NC 27708, USA
| | - Jennifer Rood
- Pennington Biomedical Research Center, Baton Rouge, LA, 70808, USA
| | - Hiroyuki Sagayama
- Faculty of Health and Sport Sciences, University of Tsukuba, Ibaraki, 305-8574, Japan
| | - Klaas R. Westerterp
- Department of Human Biology, Nutrition and Translational Research in Metabolism (NUTRIM), Maastricht University Medical Centre, Maastricht, 6200 MD, Netherlands
| | - William W. Wong
- Department of Pediatrics, Baylor College of Medicine, USDA/ARS Children's Nutrition Research Center, Houston, TX, 77030, USA
| | - Yosuke Yamada
- Institute for Active Health, Kyoto University of Advanced Science, Kyoto, Japan
- National Institute of Health and Nutrition, National Institutes of Biomedical Innovation, Health and Nutrition, Tokyo, Japan
| | - John R. Speakman
- Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, AB24 2TZ, UK
- Shenzhen Key Laboratory of Metabolic Health, Center for Energy Metabolism and Reproduction, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China
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12
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Talbot JS, Perkins DR, Dawkins TG, Douglas AJM, Griffiths TD, Richards CT, Owen K, Lord RN, Pugh CJA, Oliver JL, Lloyd RS, Ainslie PN, McManus AM, Stembridge M. Neurovascular coupling and cerebrovascular hemodynamics are modified by exercise training status at different stages of maturation during youth. Am J Physiol Heart Circ Physiol 2023; 325:H510-H521. [PMID: 37450291 PMCID: PMC10538977 DOI: 10.1152/ajpheart.00302.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 07/10/2023] [Accepted: 07/10/2023] [Indexed: 07/18/2023]
Abstract
Neurovascular coupling (NVC) is mediated via nitric oxide signaling, which is independently influenced by sex hormones and exercise training. Whether exercise training differentially modifies NVC pre- versus postpuberty, where levels of circulating sex hormones will differ greatly within and between sexes, remains to be determined. Therefore, we investigated the influence of exercise training status on resting intracranial hemodynamics and NVC at different stages of maturation. Posterior and middle cerebral artery velocities (PCAv and MCAv) and pulsatility index (PCAPI and MCAPI) were assessed via transcranial Doppler ultrasound at rest and during visual NVC stimuli. N = 121 exercise-trained (males, n = 32; females, n = 32) and untrained (males, n = 28; females, n = 29) participants were characterized as pre (males, n = 33; females, n = 29)- or post (males, n = 27; females, n = 32)-peak height velocity (PHV). Exercise-trained youth demonstrated higher resting MCAv (P = 0.010). Maturity and training status did not affect the ΔPCAv and ΔMCAv during NVC. However, pre-PHV untrained males (19.4 ± 13.5 vs. 6.8 ± 6.0%; P ≤ 0.001) and females (19.3 ± 10.8 vs. 6.4 ± 7.1%; P ≤ 0.001) had a higher ΔPCAPI during NVC than post-PHV untrained counterparts, whereas the ΔPCAPI was similar in pre- and post-PHV trained youth. Pre-PHV untrained males (19.4 ± 13.5 vs. 7.9 ± 6.0%; P ≤ 0.001) and females (19.3 ± 10.8 vs. 11.1 ± 7.3%; P = 0.016) also had a larger ΔPCAPI than their pre-PHV trained counterparts during NVC, but the ΔPCAPI was similar in trained and untrained post-PHV youth. Collectively, our data indicate that exercise training elevates regional cerebral blood velocities during youth, but training-mediated adaptations in NVC are only attainable during early stages of adolescence. Therefore, childhood provides a unique opportunity for exercise-mediated adaptations in NVC.NEW & NOTEWORTHY We report that the change in cerebral blood velocity during a neurovascular coupling task (NVC) is similar in pre- and postpubertal youth, regardless of exercise-training status. However, prepubertal untrained youth demonstrated a greater increase in cerebral blood pulsatility during the NVC task when compared with their trained counterparts. Our findings highlight that childhood represents a unique opportunity for exercise-mediated adaptations in cerebrovascular hemodynamics during NVC, which may confer long-term benefits in cerebrovascular function.
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Affiliation(s)
- Jack S Talbot
- Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, United Kingdom
- Centre for Health, Activity and Wellbeing Research, Cardiff Metropolitan University, Cardiff, United Kingdom
| | - Dean R Perkins
- Department of Sport Science, University of Innsbruck, Innsbruck, Austria
| | - Tony G Dawkins
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia Okanagan, Kelowna, British Columbia, Canada
| | - Andrew J M Douglas
- Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, United Kingdom
- Centre for Health, Activity and Wellbeing Research, Cardiff Metropolitan University, Cardiff, United Kingdom
| | - Thomas D Griffiths
- Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, United Kingdom
- Centre for Health, Activity and Wellbeing Research, Cardiff Metropolitan University, Cardiff, United Kingdom
| | - Cory T Richards
- Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, United Kingdom
- Centre for Health, Activity and Wellbeing Research, Cardiff Metropolitan University, Cardiff, United Kingdom
| | - Kerry Owen
- Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, United Kingdom
- Windsor Clive Primary School, Cardiff, United Kingdom
| | - Rachel N Lord
- Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, United Kingdom
- Centre for Health, Activity and Wellbeing Research, Cardiff Metropolitan University, Cardiff, United Kingdom
| | - Christopher J A Pugh
- Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, United Kingdom
- Centre for Health, Activity and Wellbeing Research, Cardiff Metropolitan University, Cardiff, United Kingdom
| | - Jon L Oliver
- Youth Physical Development Centre, Cardiff Metropolitan University, Cardiff, United Kingdom
- Sports Performance Research Institute New Zealand, AUT University, Auckland, New Zealand
| | - Rhodri S Lloyd
- Youth Physical Development Centre, Cardiff Metropolitan University, Cardiff, United Kingdom
- Sports Performance Research Institute New Zealand, AUT University, Auckland, New Zealand
- Centre for Sport Science and Human Performance, Waikato Institute of Technology, Waikato, New Zealand
| | - Philip N Ainslie
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia Okanagan, Kelowna, British Columbia, Canada
| | - Ali M McManus
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia Okanagan, Kelowna, British Columbia, Canada
| | - Mike Stembridge
- Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, United Kingdom
- Centre for Health, Activity and Wellbeing Research, Cardiff Metropolitan University, Cardiff, United Kingdom
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13
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Carr JMJR, Hoiland RL, Fernandes IA, Schrage WG, Ainslie PN. Recent insights into mechanisms of hypoxia-induced vasodilatation in the human brain. J Physiol 2023. [PMID: 37655827 DOI: 10.1113/jp284608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Accepted: 08/07/2023] [Indexed: 09/02/2023] Open
Abstract
The cerebral vasculature manages oxygen delivery by adjusting arterial blood in-flow in the face of reductions in oxygen availability. Hypoxic cerebral vasodilatation, and the associated hypoxic cerebral blood flow reactivity, involve many vascular, erythrocytic and cerebral tissue mechanisms that mediate elevations in cerebral blood flow via micro- and macrovascular dilatation. This contemporary review focuses on in vivo human work - with reference to seminal preclinical work where necessary - on hypoxic cerebrovascular reactivity, particularly where recent advancements have been made. We provide updates with the following information: in humans, hypoxic cerebral vasodilatation is partially mediated via a - likely non-obligatory - combination of: (1) nitric oxide synthases, (2) deoxygenation-coupled S-nitrosothiols, (3) potassium channel-related vascular smooth muscle hyperpolarization, and (4) prostaglandin mechanisms with some contribution from an interrelationship with reactive oxygen species. And finally, we discuss the fact that, due to the engagement of deoxyhaemoglobin-related mechanisms, reductions in O2 content via haemoglobin per se seem to account for ∼50% of that seen with hypoxic cerebral vasodilatation during hypoxaemia. We further highlight the issue that methodological impediments challenge the complete elucidation of hypoxic cerebral reactivity mechanisms in vivo in healthy humans. Future research is needed to confirm recent advancements and to reconcile human and animal findings. Further investigations are also required to extend these findings to address questions of sex-, heredity-, age-, and disease-related differences. The final step is to then ultimately translate understanding of these mechanisms into actionable, targetable pathways for the prevention and treatment of cerebral vascular dysfunction and cerebral hypoxic brain injury.
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Affiliation(s)
- Jay M J R Carr
- Centre for Heart, Lung and Vascular Health, University of British Columbia Okanagan, Kelowna, British Columbia, Canada
| | - Ryan L Hoiland
- Department of Anesthesiology, Pharmacology and Therapeutics, Vancouver General Hospital, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, British Columbia, Canada
- International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, British Columbia, Canada
- Collaborative Entity for Researching Brain Ischemia (CEREBRI), University of British Columbia, Vancouver, British Columbia, Canada
| | - Igor A Fernandes
- Department of Health and Kinesiology, Purdue University, Indiana, USA
| | - William G Schrage
- Department of Kinesiology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Philip N Ainslie
- Centre for Heart, Lung and Vascular Health, University of British Columbia Okanagan, Kelowna, British Columbia, Canada
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14
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Hoiland RL, MacLeod DB, Stacey BS, Caldwell HG, Howe CA, Nowak-Flück D, Carr JMJR, Tymko MM, Coombs GB, Patrician A, Tremblay JC, Van Mierlo M, Gasho C, Stembridge M, Sekhon MS, Bailey DM, Ainslie PN. Hemoglobin and cerebral hypoxic vasodilation in humans: Evidence for nitric oxide-dependent and S-nitrosothiol mediated signal transduction. J Cereb Blood Flow Metab 2023; 43:1519-1531. [PMID: 37042194 PMCID: PMC10414015 DOI: 10.1177/0271678x231169579] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Revised: 01/20/2023] [Accepted: 03/10/2023] [Indexed: 04/13/2023]
Abstract
Cerebral hypoxic vasodilation is poorly understood in humans, which undermines the development of therapeutics to optimize cerebral oxygen delivery. Across four investigations (total n = 195) we investigated the role of nitric oxide (NO) and hemoglobin-based S-nitrosothiol (RSNO) and nitrite (NO 2 - ) signaling in the regulation of cerebral hypoxic vasodilation. We conducted hemodilution (n = 10) and NO synthase inhibition experiments (n = 11) as well as hemoglobin oxygen desaturation protocols, wherein we measured cerebral blood flow (CBF), intra-arterial blood pressure, and in subsets of participants trans-cerebral release/uptake of RSNO and NO 2 - . Higher CBF during hypoxia was associated with greater trans-cerebral RSNO release but not NO 2 - , while NO synthase inhibition reduced cerebral hypoxic vasodilation. Hemodilution increased the magnitude of cerebral hypoxic vasodilation following acute hemodilution, while in 134 participants tested under normal conditions, hypoxic cerebral vasodilation was inversely correlated to arterial hemoglobin concentration. These studies were replicated in a sample of polycythemic high-altitude native Andeans suffering from excessive erythrocytosis (n = 40), where cerebral hypoxic vasodilation was inversely correlated to hemoglobin concentration, and improved with hemodilution (n = 6). Collectively, our data indicate that cerebral hypoxic vasodilation is partially NO-dependent, associated with trans-cerebral RSNO release, and place hemoglobin-based NO signaling as a central mechanism of cerebral hypoxic vasodilation in humans.
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Affiliation(s)
- Ryan L Hoiland
- Department of Anesthesiology, Pharmacology and Therapeutics, Vancouver General Hospital, University of British Columbia, Vancouver, BC, Canada
- Department of Cellular and Physiological Sciences, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, Faculty of Health and Social Development, University of British Columbia Okanagan, Kelowna, BC, Canada
- International Collaboration on Repair Discoveries, Vancouver, BC, Canada
| | - David B MacLeod
- Human Pharmacology & Physiology Lab, Department of Anesthesiology, Duke University Medical Center, Durham, NC, USA
| | - Benjamin S Stacey
- Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, Pontypridd, UK
| | - Hannah G Caldwell
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, Faculty of Health and Social Development, University of British Columbia Okanagan, Kelowna, BC, Canada
| | - Connor A Howe
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, Faculty of Health and Social Development, University of British Columbia Okanagan, Kelowna, BC, Canada
| | - Daniela Nowak-Flück
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, Faculty of Health and Social Development, University of British Columbia Okanagan, Kelowna, BC, Canada
| | - Jay MJR Carr
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, Faculty of Health and Social Development, University of British Columbia Okanagan, Kelowna, BC, Canada
| | - Michael M Tymko
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, Faculty of Health and Social Development, University of British Columbia Okanagan, Kelowna, BC, Canada
| | - Geoff B Coombs
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, Faculty of Health and Social Development, University of British Columbia Okanagan, Kelowna, BC, Canada
| | - Alexander Patrician
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, Faculty of Health and Social Development, University of British Columbia Okanagan, Kelowna, BC, Canada
| | - Joshua C Tremblay
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, Faculty of Health and Social Development, University of British Columbia Okanagan, Kelowna, BC, Canada
| | - Michelle Van Mierlo
- Department of Biomechanical Engineering, University of Twente, Enschede, The Netherlands
| | - Chris Gasho
- Department of Medicine, Division of Pulmonary and Critical Care, Loma Linda University School of Medicine, Loma Linda, CA, USA
| | - Mike Stembridge
- Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, UK
| | - Mypinder S Sekhon
- International Collaboration on Repair Discoveries, Vancouver, BC, Canada
- Djavad Mowafaghian Centre for Brain Health, Department of Pathology and Laboratory Medicine, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
- Division of Critical Care Medicine, Department of Medicine, Vancouver General Hospital, University of British Columbia, Vancouver, BC, Canada
| | - Damian M Bailey
- Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, Pontypridd, UK
| | - Philip N Ainslie
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, Faculty of Health and Social Development, University of British Columbia Okanagan, Kelowna, BC, Canada
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15
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Patrician A, Willie C, Hoiland RL, Gasho C, Subedi P, Anholm JD, Tymko MM, Ainslie PN. Manipulation of iron status on cerebral blood flow at high altitude in lowlanders and adapted highlanders. J Cereb Blood Flow Metab 2023; 43:1166-1179. [PMID: 36883428 PMCID: PMC10291452 DOI: 10.1177/0271678x231152734] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 01/27/2023] [Accepted: 12/05/2022] [Indexed: 03/09/2023]
Abstract
Cerebral blood flow (CBF) increases during hypoxia to counteract the reduction in arterial oxygen content. The onset of tissue hypoxemia coincides with the stabilization of hypoxia-inducible factor (HIF) and transcription of downstream HIF-mediated processes. It has yet to be determined, whether HIF down- or upregulation can modulate hypoxic vasodilation of the cerebral vasculature. Therefore, we examined whether: 1) CBF would increase with iron depletion (via chelation) and decrease with repletion (via iron infusion) at high-altitude, and 2) explore whether genotypic advantages of highlanders extend to HIF-mediated regulation of CBF. In a double-blinded and block-randomized design, CBF was assessed in 82 healthy participants (38 lowlanders, 20 Sherpas and 24 Andeans), before and after the infusion of either: iron(III)-hydroxide sucrose, desferrioxamine or saline. Across both lowlanders and highlanders, baseline iron levels contributed to the variability in cerebral hypoxic reactivity at high altitude (R2 = 0.174, P < 0.001). At 5,050 m, CBF in lowlanders and Sherpa were unaltered by desferrioxamine or iron. At 4,300 m, iron infusion led to 4 ± 10% reduction in CBF (main effect of time p = 0.043) in lowlanders and Andeans. Iron status may provide a novel, albeit subtle, influence on CBF that is potentially dependent on the severity and length-of-stay at high altitude.
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Affiliation(s)
- Alexander Patrician
- Centre for Heart, Lung, & Vascular Health, School of Health and Exercise Sciences, University of British Columbia – Okanagan, Kelowna, BC, Canada
| | - Christopher Willie
- Centre for Heart, Lung, & Vascular Health, School of Health and Exercise Sciences, University of British Columbia – Okanagan, Kelowna, BC, Canada
| | - Ryan L Hoiland
- Centre for Heart, Lung, & Vascular Health, School of Health and Exercise Sciences, University of British Columbia – Okanagan, Kelowna, BC, Canada
- Department of Anesthesiology, Pharmacology and Therapeutics, Faculty of Medicine, Vancouver General Hospital, University of British Columbia, Vancouver, BC, Canada
- Department of Cellular and Physiological Sciences, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
- International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, British Columbia, Canada
| | - Christopher Gasho
- Pulmonary/Critical Care Section, VA Loma Linda Healthcare System and Department of Medicine, Loma Linda University, Loma Linda, CA, USA
| | - Prajan Subedi
- Pulmonary/Critical Care Section, VA Loma Linda Healthcare System and Department of Medicine, Loma Linda University, Loma Linda, CA, USA
| | - James D Anholm
- Pulmonary/Critical Care Section, VA Loma Linda Healthcare System and Department of Medicine, Loma Linda University, Loma Linda, CA, USA
| | - Michael M Tymko
- Centre for Heart, Lung, & Vascular Health, School of Health and Exercise Sciences, University of British Columbia – Okanagan, Kelowna, BC, Canada
| | - Philip N Ainslie
- Centre for Heart, Lung, & Vascular Health, School of Health and Exercise Sciences, University of British Columbia – Okanagan, Kelowna, BC, Canada
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16
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Janssen Daalen JM, Meinders MJ, Straatsma IR, Ainslie PN, Thijssen DHJ, Bloem BR. Reply to: Hypoxia treatment of Parkinson's disease may disrupt the circadian system. BMC Neurol 2023; 23:235. [PMID: 37337147 DOI: 10.1186/s12883-023-03281-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Accepted: 06/07/2023] [Indexed: 06/21/2023] Open
Affiliation(s)
- Jules M Janssen Daalen
- Center of Expertise for Parkinson & Movement Disorders, Nijmegen, The Netherlands.
- Department of Neurology, Radboud University Medical Center, Donders Institute for Brain, Cognition and Behavior, Nijmegen, The Netherlands.
- Department of Physiology, Department of Medical BioSciences, Radboud University Medical Center, Nijmegen, The Netherlands.
| | - Marjan J Meinders
- Center of Expertise for Parkinson & Movement Disorders, Nijmegen, The Netherlands
- Department of Neurology, Radboud University Medical Center, Donders Institute for Brain, Cognition and Behavior, Nijmegen, The Netherlands
- IQ Healthcare, Radboud Institute for Health Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Isabel R Straatsma
- Department of Physiology, Department of Medical BioSciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Philip N Ainslie
- Center for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, Canada
| | - Dick H J Thijssen
- Department of Physiology, Department of Medical BioSciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Bastiaan R Bloem
- Center of Expertise for Parkinson & Movement Disorders, Nijmegen, The Netherlands
- Department of Neurology, Radboud University Medical Center, Donders Institute for Brain, Cognition and Behavior, Nijmegen, The Netherlands
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17
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Park AJ, Fandl HK, Garcia VP, Coombs GB, DeSouza NM, Greiner JJ, Barak OF, Mijacika T, Dujic Z, Ainslie PN, DeSouza CA. Differential Expression of Vascular-Related MicroRNA in Circulating Endothelial Microvesicles in Adults With Spinal Cord Injury: A Pilot Study. Top Spinal Cord Inj Rehabil 2023; 29:34-42. [PMID: 37235195 PMCID: PMC10208256 DOI: 10.46292/sci22-00032] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/03/2024]
Abstract
Background Spinal cord injury (SCI) is associated with an increased risk and prevalence of cardiopulmonary and cerebrovascular disease-related morbidity and mortality. The factors that initiate, promote, and accelerate vascular diseases and events in SCI are poorly understood. Clinical interest in circulating endothelial cell-derived microvesicles (EMVs) and their microRNA (miRNA) cargo has intensified due to their involvement in endothelial dysfunction, atherosclerosis, and cerebrovascular events. Objectives The aim of this study was to determine whether a subset of vascular-related miRNAs is differentially expressed in EMVs isolated from adults with SCI. Methods We assessed eight adults with tetraplegia (7 male/1 female; age: 46±4 years; time since injury: 26±5 years) and eight uninjured (6 male/2 female; age: 39±3 years). Circulating EMVs were isolated, enumerated, and collected from plasma by flow cytometry. The expression of vascular-related miRNAs in EMVs was assessed by RT-PCR. Results Circulating EMV levels were significantly higher (~130%) in adults with SCI compared with uninjured adults. The expression profile of miRNAs in EMVs from adults with SCI were significantly different than uninjured adults and were pathologic in nature. Expression of miR-126, miR-132, and miR-Let-7a were lower (~100-150%; p < .05), whereas miR-30a, miR-145, miR-155, and miR-216 were higher (~125-450%; p < .05) in EMVs from adults with SCI. Conclusion This study is the first examination of EMV miRNA cargo in adults with SCI. The cargo signature of vascular-related miRNAs studied reflects a pathogenic EMV phenotype prone to induce inflammation, atherosclerosis, and vascular dysfunction. EMVs and their miRNA cargo represent a novel biomarker of vascular risk and a potential target for intervention to alleviate vascular-related disease after SCI.
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Affiliation(s)
- Andrew J Park
- Rocky Mountain Regional Spinal Injury System, Craig Hospital, Englewood, Colorado
- University of Colorado, Department of Physical Medicine and Rehabilitation, Aurora, Colorado
| | - Hannah K Fandl
- Integrative Vascular Biology Laboratory, Department of Integrative Physiology, University of Colorado, Boulder, Colorado
| | - Vinicius P Garcia
- Integrative Vascular Biology Laboratory, Department of Integrative Physiology, University of Colorado, Boulder, Colorado
| | - Geoff B Coombs
- University of Western Ontario, School of Kinesiology, London, Ontario, Canada
| | - Noah M DeSouza
- Integrative Vascular Biology Laboratory, Department of Integrative Physiology, University of Colorado, Boulder, Colorado
- Centre for Heart, Lung and Vascular Health, University of British Columbia Okanagan, Kelowna, British Columbia, Canada
| | - Jared J Greiner
- Integrative Vascular Biology Laboratory, Department of Integrative Physiology, University of Colorado, Boulder, Colorado
| | - Otto F Barak
- Department of Sports Medicine, University of Novi Sad, Serbia
- Department of Integrative Physiology, University of Split School of Medicine, Split, Croatia
| | - Tanja Mijacika
- Department of Integrative Physiology, University of Split School of Medicine, Split, Croatia
| | - Zeljko Dujic
- Department of Integrative Physiology, University of Split School of Medicine, Split, Croatia
| | - Philip N Ainslie
- Centre for Heart, Lung and Vascular Health, University of British Columbia Okanagan, Kelowna, British Columbia, Canada
| | - Christopher A DeSouza
- Integrative Vascular Biology Laboratory, Department of Integrative Physiology, University of Colorado, Boulder, Colorado
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18
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Speakman JR, de Jong JMA, Sinha S, Westerterp KR, Yamada Y, Sagayama H, Ainslie PN, Anderson LJ, Arab L, Bedu-Addo K, Blanc S, Bonomi AG, Bovet P, Brage S, Buchowski MS, Butte NF, Camps SGJA, Cooper JA, Cooper R, Das SK, Davies PSW, Dugas LR, Ekelund U, Entringer S, Forrester T, Fudge BW, Gillingham M, Ghosh S, Goris AH, Gurven M, Halsey LG, Hambly C, Haisma HH, Hoffman D, Hu S, Joosen AM, Kaplan JL, Katzmarzyk P, Kraus WE, Kushner RF, Leonard WR, Löf M, Martin CK, Matsiko E, Medin AC, Meijer EP, Neuhouser ML, Nicklas TA, Ojiambo RM, Pietiläinen KH, Plange-Rhule J, Plasqui G, Prentice RL, Racette SB, Raichlen DA, Ravussin E, Redman LM, Roberts SB, Rudolph MC, Sardinha LB, Schuit AJ, Silva AM, Stice E, Urlacher SS, Valenti G, Van Etten LM, Van Mil EA, Wood BM, Yanovski JA, Yoshida T, Zhang X, Murphy-Alford AJ, Loechl CU, Kurpad A, Luke AH, Pontzer H, Rodeheffer MS, Rood J, Schoeller DA, Wong WW. Total daily energy expenditure has declined over the past three decades due to declining basal expenditure, not reduced activity expenditure. Nat Metab 2023; 5:579-588. [PMID: 37100994 PMCID: PMC10445668 DOI: 10.1038/s42255-023-00782-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Accepted: 03/08/2023] [Indexed: 04/28/2023]
Abstract
Obesity is caused by a prolonged positive energy balance1,2. Whether reduced energy expenditure stemming from reduced activity levels contributes is debated3,4. Here we show that in both sexes, total energy expenditure (TEE) adjusted for body composition and age declined since the late 1980s, while adjusted activity energy expenditure increased over time. We use the International Atomic Energy Agency Doubly Labelled Water database on energy expenditure of adults in the United States and Europe (n = 4,799) to explore patterns in total (TEE: n = 4,799), basal (BEE: n = 1,432) and physical activity energy expenditure (n = 1,432) over time. In males, adjusted BEE decreased significantly, but in females this did not reach significance. A larger dataset of basal metabolic rate (equivalent to BEE) measurements of 9,912 adults across 163 studies spanning 100 years replicates the decline in BEE in both sexes. We conclude that increasing obesity in the United States/Europe has probably not been fuelled by reduced physical activity leading to lowered TEE. We identify here a decline in adjusted BEE as a previously unrecognized factor.
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Affiliation(s)
- John R Speakman
- Shenzhen Key Laboratory of Metabolic Health, Center for Energy Metabolism and Reproduction, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China.
- Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, UK.
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China.
- CAS Center of Excellence in Animal Evolution and Genetics, Kunming, China.
| | - Jasper M A de Jong
- Department of Comparative Medicine, Yale School of Medicine, New Haven, CT, USA
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Srishti Sinha
- St Johns Medical college, Bengaluru, India
- Nutritional and Health Related Environmental Studies Section, Division of Human Health, International Atomic Energy Agency, Vienna, Austria
| | - Klaas R Westerterp
- School of Nutrition and Translational Research in Metabolism (NUTRIM), University of Maastricht, Maastricht, the Netherlands.
| | - Yosuke Yamada
- National Institute of Health and Nutrition, National Institutes of Biomedical Innovation, Health and Nutrition, Tokyo, Japan.
- Institute for Active Health, Kyoto University of Advanced Science, Kyoto, Japan.
| | - Hiroyuki Sagayama
- Faculty of Health and Sport Sciences, University of Tsukuba, Ibaraki, Japan.
| | - Philip N Ainslie
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK
| | - Liam J Anderson
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, UK
| | - Lenore Arab
- David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - Kweku Bedu-Addo
- Department of Physiology, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Stephane Blanc
- Nutritional Sciences, University of Wisconsin, Madison, WI, USA
- Institut Pluridisciplinaire Hubert Curien, CNRS Université de Strasbourg, Strasbourg, France
| | | | - Pascal Bovet
- University Center for Primary care and Public Health (Unisanté), Lausanne University Hospital, Lausanne, Switzerland
- Ministry of Health, Victoria, Seychelles
| | - Soren Brage
- MRC Epidemiology Unit, University of Cambridge, Cambridge, UK
| | - Maciej S Buchowski
- Division of Gastroenterology, Hepatology and Nutritiion, Department of Medicine, Vanderbilt University, Nashville, TN, USA
| | - Nancy F Butte
- Department of Pediatrics, Baylor College of Medicine, USDA/ARS Children's Nutrition Research Center, Houston, TX, USA
| | - Stefan G J A Camps
- School of Nutrition and Translational Research in Metabolism (NUTRIM), University of Maastricht, Maastricht, the Netherlands
| | - Jamie A Cooper
- Nutritional Sciences, University of Wisconsin, Madison, WI, USA
- Nutritional Sciences, University of Georgia, Athens, GA, USA
| | - Richard Cooper
- Department of Public Health Sciences, Parkinson School of Health Sciences and Public Health, Loyola University, Maywood, IL, USA
| | - Sai Krupa Das
- Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston, MA, USA
| | - Peter S W Davies
- Child Health Research Centre, Centre for Children's Health Research, University of Queensland, South Brisbane, Queensland, Australia
| | - Lara R Dugas
- Department of Public Health Sciences, Parkinson School of Health Sciences and Public Health, Loyola University, Maywood, IL, USA
- Division of Epidemiology and Biostatistics, School of Public Health and Family Medicine, University of Cape Town, Cape Town, South Africa
| | - Ulf Ekelund
- Department of Sport Medicine, Norwegian School of Sport Sciences, Oslo, Norway
| | - Sonja Entringer
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health (BIH), Institute of Medical Psychology, Berlin, Germany
- University of California Irvine, Irvine, CA, USA
| | - Terrence Forrester
- Solutions for Developing Countries, University of the West Indies, Kingston, Jamaica
| | | | - Melanie Gillingham
- Department of Molecular and Medical Genetics, Oregon Health & Science University, Portland, OR, USA
| | | | - Annelies H Goris
- IMEC within OnePlanet Research Center, Wageningen, the Netherlands
| | - Michael Gurven
- Department of Anthropology, University of California Santa Barbara, Santa Barbara, CA, USA
| | - Lewis G Halsey
- School of Life and Health Sciences, University of Roehampton, London, UK
| | - Catherine Hambly
- Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, UK
| | - Hinke H Haisma
- Population Research Centre, Faculty of Spatial Sciences, University of Groningen, Groningen, the Netherlands
| | - Daniel Hoffman
- Department of Nutritional Sciences, Program in International Nutrition, Rutgers University, New Brunswick, NJ, USA
| | - Sumei Hu
- Shenzhen Key Laboratory of Metabolic Health, Center for Energy Metabolism and Reproduction, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, Beijing Engineering and Technology Research Center of Food Additives, National Soybean Processing Industry Technology Innovation Center, Beijing Technology and Business University, Beijing, China
| | - Annemiek M Joosen
- School of Nutrition and Translational Research in Metabolism (NUTRIM), University of Maastricht, Maastricht, the Netherlands
| | - Jennifer L Kaplan
- Department of Comparative Medicine, Yale School of Medicine, New Haven, CT, USA
| | | | | | | | - William R Leonard
- Department of Anthropology, Northwestern University, Evanston, IL, USA
| | - Marie Löf
- Department of Biosciences and Nutrition, Karolinska Institute, Stockholm, Sweden
- Department of Health, Medicine and Caring Sciences, Linköping University, Linköping, Sweden
| | - Corby K Martin
- Pennington Biomedical Research Center, Baton Rouge, LA, USA
| | - Eric Matsiko
- Department of Human Nutrition and Dietetics, University of Rwanda, Kigali, Rwanda
| | - Anine C Medin
- Department of Nutrition and Public Health, Faculty of Health and Sport Sciences, University of Agder, Kristiansand, Norway
- Department of Nutrition, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Erwin P Meijer
- School of Nutrition and Translational Research in Metabolism (NUTRIM), University of Maastricht, Maastricht, the Netherlands
| | - Marian L Neuhouser
- Division of Public Health Sciences, Fred Hutchinson Cancer Center and School of Public Health, University of Washington, Seattle, WA, USA
| | - Theresa A Nicklas
- Department of Pediatrics, Baylor College of Medicine, USDA/ARS Children's Nutrition Research Center, Houston, TX, USA
| | - Robert M Ojiambo
- Moi University, Eldoret, Kenya
- University of Global Health Equity, Kigali, Rwanda
| | | | - Jacob Plange-Rhule
- Department of Physiology, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Guy Plasqui
- Department of Nutrition and Movement Sciences, Maastricht University, Maastricht, the Netherlands
| | - Ross L Prentice
- Division of Public Health Sciences, Fred Hutchinson Cancer Center and School of Public Health, University of Washington, Seattle, WA, USA
| | - Susan B Racette
- Program in Physical Therapy and Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA
| | - David A Raichlen
- Biological Sciences and Anthropology, University of Southern California, Los Angeles, CA, USA
| | - Eric Ravussin
- Pennington Biomedical Research Center, Baton Rouge, LA, USA
| | | | - Susan B Roberts
- Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, Boston, MA, USA
| | - Michael C Rudolph
- Department of Physiology and Harold Hamm Diabetes Center, Oklahoma University Health Sciences, Oklahoma City, OK, USA
| | - Luis B Sardinha
- Exercise and Health Laboratory, CIPER, Faculdade de Motricidade Humana, Universidade de Lisboa, Lisboa, Portugal
| | | | - Analiza M Silva
- Exercise and Health Laboratory, CIPER, Faculdade de Motricidade Humana, Universidade de Lisboa, Lisboa, Portugal
| | | | - Samuel S Urlacher
- Department of Anthropology, Baylor University, Waco, TX, USA
- Child and Brain Development program, CIFAR, Toronto, Ontario, Canada
| | - Giulio Valenti
- School of Nutrition and Translational Research in Metabolism (NUTRIM), University of Maastricht, Maastricht, the Netherlands
| | - Ludo M Van Etten
- School of Nutrition and Translational Research in Metabolism (NUTRIM), University of Maastricht, Maastricht, the Netherlands
| | - Edgar A Van Mil
- Maastricht University, Campus Venlo and Lifestyle Medicine Center for Children, Jeroen Bosch Hospital's-Hertogenbosch, Hertogenbosch, the Netherlands
| | - Brian M Wood
- University of California Los Angeles, Los Angeles, CA, USA
- Department of Human Behavior, Ecology, and Culture, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - Jack A Yanovski
- Section on Growth and Obesity, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Tsukasa Yoshida
- National Institute of Health and Nutrition, National Institutes of Biomedical Innovation, Health and Nutrition, Tokyo, Japan
| | - Xueying Zhang
- Shenzhen Key Laboratory of Metabolic Health, Center for Energy Metabolism and Reproduction, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
- Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, UK
| | - Alexia J Murphy-Alford
- Nutritional and Health Related Environmental Studies Section, Division of Human Health, International Atomic Energy Agency, Vienna, Austria
| | - Cornelia U Loechl
- Nutritional and Health Related Environmental Studies Section, Division of Human Health, International Atomic Energy Agency, Vienna, Austria
| | | | - Amy H Luke
- Division of Epidemiology, Department of Public Health Sciences, Loyola University School of Medicine, Maywood, IL, USA.
| | - Herman Pontzer
- Evolutionary Anthropology, Duke University, Durham, NC, USA.
- Duke Global Health Institute, Duke University, Durham, NC, USA.
| | - Matthew S Rodeheffer
- Department of Comparative Medicine, Yale School of Medicine, New Haven, CT, USA.
- Center of Molecular and Systems Metabolism, Yale University, New Haven, CT, USA.
- Department of Physiology, Yale University, New Haven, CT, USA.
| | - Jennifer Rood
- Pennington Biomedical Research Center, Baton Rouge, LA, USA.
| | - Dale A Schoeller
- Biotech Center and Nutritional Sciences, University of Wisconsin, Madison, WI, USA.
| | - William W Wong
- Department of Pediatrics, Baylor College of Medicine, USDA/ARS Children's Nutrition Research Center, Houston, TX, USA.
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19
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Simpson LL, Hansen AB, Moralez G, Amin SB, Hofstaetter F, Gasho C, Stembridge M, Dawkins TG, Tymko MM, Ainslie PN, Lawley JS, Hearon CM. Adrenergic control of skeletal muscle blood flow during chronic hypoxia in healthy males. Am J Physiol Regul Integr Comp Physiol 2023; 324:R457-R469. [PMID: 36717165 PMCID: PMC10026988 DOI: 10.1152/ajpregu.00230.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 01/24/2023] [Accepted: 01/24/2023] [Indexed: 02/01/2023]
Abstract
Sympathetic transduction is reduced following chronic high-altitude (HA) exposure; however, vascular α-adrenergic signaling, the primary mechanism mediating sympathetic vasoconstriction at sea level (SL), has not been examined at HA. In nine male lowlanders, we measured forearm blood flow (Doppler ultrasound) and calculated changes in vascular conductance (ΔFVC) during 1) incremental intra-arterial infusion of phenylephrine to assess α1-adrenergic receptor responsiveness and 2) combined intra-arterial infusion of β-adrenergic and α-adrenergic antagonists propranolol and phentolamine (α-β-blockade) to assess adrenergic vascular restraint at rest and during exercise-induced sympathoexcitation (cycling; 60% peak power). Experiments were performed near SL (344 m) and after 3 wk at HA (4,383 m). HA abolished the vasoconstrictor response to low-dose phenylephrine (ΔFVC: SL: -34 ± 15%, vs. HA; +3 ± 18%; P < 0.0001) and markedly attenuated the response to medium (ΔFVC: SL: -45 ± 18% vs. HA: -28 ± 11%; P = 0.009) and high (ΔFVC: SL: -47 ± 20%, vs. HA: -35 ± 20%; P = 0.041) doses. Blockade of β-adrenergic receptors alone had no effect on resting FVC (P = 0.500) and combined α-β-blockade induced a similar vasodilatory response at SL and HA (P = 0.580). Forearm vasoconstriction during cycling was not different at SL and HA (P = 0.999). Interestingly, cycling-induced forearm vasoconstriction was attenuated by α-β-blockade at SL (ΔFVC: Control: -27 ± 128 vs. α-β-blockade: +19 ± 23%; P = 0.0004), but unaffected at HA (ΔFVC: Control: -20 ± 22 vs. α-β-blockade: -23 ± 11%; P = 0.999). Our results indicate that in healthy males, altitude acclimatization attenuates α1-adrenergic receptor responsiveness; however, resting α-adrenergic restraint remains intact, due to concurrent resting sympathoexcitation. Furthermore, forearm vasoconstrictor responses to cycling are preserved, although the contribution of adrenergic receptors is diminished, indicating a reliance on alternative vasoconstrictor mechanisms.
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Affiliation(s)
- Lydia L Simpson
- Department of Sport Science, Division of Performance Physiology and Prevention, Universität Innsbruck, Innsbruck, Austria
| | - Alexander B Hansen
- Department of Sport Science, Division of Performance Physiology and Prevention, Universität Innsbruck, Innsbruck, Austria
| | - Gilbert Moralez
- Department of Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, Texas, United States
| | - Sachin B Amin
- Department of Sport Science, Division of Performance Physiology and Prevention, Universität Innsbruck, Innsbruck, Austria
| | - Florian Hofstaetter
- Department of Sport Science, Division of Performance Physiology and Prevention, Universität Innsbruck, Innsbruck, Austria
| | - Christopher Gasho
- Department of Medicine, Division of Pulmonary and Critical Care, Loma Linda University, Loma Linda, California, United States
| | - Mike Stembridge
- Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, Wales, United Kingdom
| | - Tony G Dawkins
- Centre of Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, British Columbia, Canada
| | - Michael M Tymko
- Centre of Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, British Columbia, Canada
- Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Edmonton, Alberta, Canada
- Department of Medicine, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Philip N Ainslie
- Centre of Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, British Columbia, Canada
| | - Justin S Lawley
- Department of Sport Science, Division of Performance Physiology and Prevention, Universität Innsbruck, Innsbruck, Austria
- Institute of Mountain Emergency Medicine, Eurac Research, Bolzano, Italy
| | - Christopher M Hearon
- Department of Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, Texas, United States
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Dallas, Dallas, Texas, United States
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20
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Stacey BS, Hoiland RL, Caldwell HG, Howe CA, Vermeulen T, Tymko MM, Vizcardo‐Galindo GA, Bermudez D, Figueroa‐Mujíica RJ, Gasho C, Tuaillon E, Hirtz C, Lehmann S, Marchi N, Tsukamoto H, Villafuerte FC, Ainslie PN, Bailey DM. Lifelong exposure to high-altitude hypoxia in humans is associated with improved redox homeostasis and structural-functional adaptations of the neurovascular unit. J Physiol 2023; 601:1095-1120. [PMID: 36633375 PMCID: PMC10952731 DOI: 10.1113/jp283362] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Accepted: 12/20/2022] [Indexed: 01/13/2023] Open
Abstract
High-altitude (HA) hypoxia may alter the structural-functional integrity of the neurovascular unit (NVU). Herein, we compared male lowlanders (n = 9) at sea level (SL) and after 14 days acclimatization to 4300 m (chronic HA) in Cerro de Pasco (CdP), Péru (HA), against sex-, age- and body mass index-matched healthy highlanders (n = 9) native to CdP (lifelong HA). Venous blood was assayed for serum proteins reflecting NVU integrity, in addition to free radicals and nitric oxide (NO). Regional cerebral blood flow (CBF) was examined in conjunction with cerebral substrate delivery, dynamic cerebral autoregulation (dCA), cerebrovascular reactivity to carbon dioxide (CVRCO2 ) and neurovascular coupling (NVC). Psychomotor tests were employed to examine cognitive function. Compared to lowlanders at SL, highlanders exhibited elevated basal plasma and red blood cell NO bioavailability, improved anterior and posterior dCA, elevated anterior CVRCO2 and preserved cerebral substrate delivery, NVC and cognition. In highlanders, S100B, neurofilament light-chain (NF-L) and T-tau were consistently lower and cognition comparable to lowlanders following chronic-HA. These findings highlight novel integrated adaptations towards regulation of the NVU in highlanders that may represent a neuroprotective phenotype underpinning successful adaptation to the lifelong stress of HA hypoxia. KEY POINTS: High-altitude (HA) hypoxia has the potential to alter the structural-functional integrity of the neurovascular unit (NVU) in humans. For the first time, we examined to what extent chronic and lifelong hypoxia impacts multimodal biomarkers reflecting NVU structure and function in lowlanders and native Andean highlanders. Despite lowlanders presenting with a reduction in systemic oxidative-nitrosative stress and maintained cerebral bioenergetics and cerebrovascular function during chronic hypoxia, there was evidence for increased axonal injury and cognitive impairment. Compared to lowlanders at sea level, highlanders exhibited elevated vascular NO bioavailability, improved dynamic regulatory capacity and cerebrovascular reactivity, comparable cerebral substrate delivery and neurovascular coupling, and maintained cognition. Unlike lowlanders following chronic HA, highlanders presented with lower concentrations of S100B, neurofilament light chain and total tau. These findings highlight novel integrated adaptations towards the regulation of the NVU in highlanders that may represent a neuroprotective phenotype underpinning successful adaptation to the lifelong stress of HA hypoxia.
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Affiliation(s)
- Benjamin S. Stacey
- Neurovascular Research Laboratory, Faculty of Life Sciences and EducationUniversity of South WalesPontypriddUK
| | - Ryan L. Hoiland
- Department of Anaesthesiology, Pharmacology and Therapeutics, Vancouver General HospitalUniversity of British ColumbiaVancouverBritish ColumbiaCanada
- Department of Cellular and Physiological Sciences, Faculty of MedicineUniversity of British ColumbiaVancouverBritish ColumbiaCanada
| | - Hannah G. Caldwell
- Centre for Heart, Lung and Vascular HealthUniversity of British Columbia‐Okanagan CampusKelownaBritish ColumbiaCanada
| | - Connor A. Howe
- Centre for Heart, Lung and Vascular HealthUniversity of British Columbia‐Okanagan CampusKelownaBritish ColumbiaCanada
| | - Tyler Vermeulen
- Centre for Heart, Lung and Vascular HealthUniversity of British Columbia‐Okanagan CampusKelownaBritish ColumbiaCanada
| | - Michael M. Tymko
- Centre for Heart, Lung and Vascular HealthUniversity of British Columbia‐Okanagan CampusKelownaBritish ColumbiaCanada
- Faculty of Kinesiology, Sport, and RecreationUniversity of AlbertaEdmontonAlbertaCanada
- Department of Medicine, Faculty of MedicineUniversity of British ColumbiaVancouverBritish ColumbiaCanada
| | - Gustavo A. Vizcardo‐Galindo
- Laboratorio de Fisiología Comparada, Departamento de Ciencias Biológicas y Fisiológicas, Facultad de Ciencias y FilosofíaUniversidad Peruana Cayetano HerediaLima 31Peru
| | - Daniella Bermudez
- Laboratorio de Fisiología Comparada, Departamento de Ciencias Biológicas y Fisiológicas, Facultad de Ciencias y FilosofíaUniversidad Peruana Cayetano HerediaLima 31Peru
| | - Rómulo J. Figueroa‐Mujíica
- Laboratorio de Fisiología Comparada, Departamento de Ciencias Biológicas y Fisiológicas, Facultad de Ciencias y FilosofíaUniversidad Peruana Cayetano HerediaLima 31Peru
| | - Christopher Gasho
- Division of Pulmonary and Critical CareLoma Linda University School of MedicineLoma LindaCAUSA
| | - Edouard Tuaillon
- Department of Infectious DiseasesUniversity of MontpellierMontpellierFrance
| | - Christophe Hirtz
- LBPC‐PPCUniversité de Montpellier, IRMB CHU de Montpellier, INM INSERMMontpellierFrance
| | - Sylvain Lehmann
- LBPC‐PPCUniversité de Montpellier, IRMB CHU de Montpellier, INM INSERMMontpellierFrance
| | - Nicola Marchi
- Laboratory of Cerebrovascular and Glia Research, Department of Neuroscience, Institute of Functional GenomicsUniversity of MontpellierMontpellierFrance
| | - Hayato Tsukamoto
- Faculty of Sport and Health ScienceRitsumeikan UniversityKusatsuShigaJapan
| | - Francisco C. Villafuerte
- Laboratorio de Fisiología Comparada, Departamento de Ciencias Biológicas y Fisiológicas, Facultad de Ciencias y FilosofíaUniversidad Peruana Cayetano HerediaLima 31Peru
| | - Philip N. Ainslie
- Neurovascular Research Laboratory, Faculty of Life Sciences and EducationUniversity of South WalesPontypriddUK
- Centre for Heart, Lung and Vascular HealthUniversity of British Columbia‐Okanagan CampusKelownaBritish ColumbiaCanada
| | - Damian M. Bailey
- Neurovascular Research Laboratory, Faculty of Life Sciences and EducationUniversity of South WalesPontypriddUK
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21
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Vizcardo-Galindo GA, Howe CA, Hoiland RL, Carter HH, Willie CK, Ainslie PN, Tremblay JC. Impact of Oxygen Supplementation on Brachial Artery Hemodynamics and Vascular Function During Ascent to 5,050 m. High Alt Med Biol 2023; 24:27-36. [PMID: 36940101 DOI: 10.1089/ham.2022.0107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/21/2023] Open
Abstract
Vizcardo-Galindo, Gustavo A., Connor A. Howe, Ryan L. Hoiland, Howard H. Carter, Christopher K. Willie, Philip N. Ainslie, and Joshua C. Tremblay. Impact of oxygen supplementation on brachial artery hemodynamics and vascular function during ascent to 5,050 m. High Alt Med Biol. 24:27-36, 2023.-High-altitude trekking alters upper limb hemodynamics and reduces brachial artery vascular function in lowlanders. Whether these changes are reversible with the removal of hypoxia is unknown. We investigated the impact of 20 minutes of oxygen supplementation (O2) on brachial artery hemodynamics, reactive hyperemia (RH; microvascular function), and flow-mediated dilation (FMD; endothelial function). Participants (aged 21-42 years) were examined before and with O2 at 3,440 m (n = 7), 4,371 m (n = 7), and 5,050 m (n = 12) using Duplex ultrasound (days 4, 7, and 10 respectively). At 3,440 m, O2 decreased brachial artery diameter (-5% ± 5%; p = 0.04), baseline blood flow (-44% ± 15%; p < 0.001), oxygen delivery (-39 ± 16; p < 0.001), and peak RH (-8% ± 8%; p = 0.02), but not RH normalized for baseline blood flow. Elevated FMD (p = 0.04) with O2 at 3,440 m was attributed to the reduction in baseline diameter. At 5,050 m, a reduction in brachial artery blood flow (-17% ± 22%; p = 0.03), but not oxygen delivery, diameter, RH, or FMD occurred with O2. These findings suggest that during early trekking at high altitude, O2 causes vasoconstriction in the upper limb along the arterial tree (conduit and resistance arteries). With incremental high-altitude exposure, O2 reduces blood flow without compromising oxygen delivery, RH, or FMD, suggesting a differential impact on vascular function modulated by the duration and severity of high-altitude exposure.
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Affiliation(s)
- Gustavo A Vizcardo-Galindo
- Centre for Heart, Lung & Vascular Health, Faculty of Health and Social Development, University of British Columbia-Okanagan, Kelowna, Canada
| | - Connor A Howe
- Centre for Heart, Lung & Vascular Health, Faculty of Health and Social Development, University of British Columbia-Okanagan, Kelowna, Canada
| | - Ryan L Hoiland
- Centre for Heart, Lung & Vascular Health, Faculty of Health and Social Development, University of British Columbia-Okanagan, Kelowna, Canada
- Department of Anesthesiology, Pharmacology and Therapeutics, Vancouver General Hospital, University of British Columbia, Vancouver, Canada
- Department of Cellular and Physiological Sciences, Faculty of Medicine, University of British Columbia, Vancouver, Canada
- International Collaboration on Repair Discoveries, Vancouver, Canada
| | - Howard H Carter
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
- Cardiovascular Research Group, School of Human Sciences (Exercise and Sport Science), University of Western Australia, Perth, Australia
| | - Christopher K Willie
- Centre for Heart, Lung & Vascular Health, Faculty of Health and Social Development, University of British Columbia-Okanagan, Kelowna, Canada
| | - Philip N Ainslie
- Centre for Heart, Lung & Vascular Health, Faculty of Health and Social Development, University of British Columbia-Okanagan, Kelowna, Canada
| | - Joshua C Tremblay
- Centre for Heart, Lung & Vascular Health, Faculty of Health and Social Development, University of British Columbia-Okanagan, Kelowna, Canada
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22
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Gibbons TD, Cotter JD, Ainslie PN, Abraham WC, Mockett BG, Campbell HA, Jones EMW, Jenkins EJ, Thomas KN. Fasting for 20 h does not affect exercise-induced increases in circulating BDNF in humans. J Physiol 2023. [PMID: 36631068 DOI: 10.1113/jp283582] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Accepted: 11/18/2022] [Indexed: 01/13/2023] Open
Abstract
Intermittent fasting and exercise provide neuroprotection from age-related cognitive decline. A link between these two seemingly distinct stressors is their capability to steer the brain away from exclusively glucose metabolism. This cerebral substrate switch has been implicated in upregulating brain-derived neurotrophic factor (BDNF), a protein involved in neuroplasticity, learning and memory, and may underlie some of these neuroprotective effects. We examined the isolated and interactive effects of (1) 20-h fasting, (2) 90-min light exercise, and (3) high-intensity exercise on peripheral venous BDNF in 12 human volunteers. A follow-up study isolated the influence of cerebrovascular shear stress on circulating BDNF. Fasting for 20 h decreased glucose and increased ketones (P ≤ 0.0157) but had no effect on BDNF (P ≥ 0.4637). Light cycling at 25% of peak oxygen uptake ( V ̇ O 2 peak ${\dot V_{{{\rm{O}}_{\rm{2}}}{\rm{peak}}}}$ ) increased serum BDNF by 6 ± 8% (independent of being fed or fasted) and was mediated by a 7 ± 6% increase in platelets (P < 0.0001). Plasma BDNF was increased from 336 pg l-1 [46,626] to 390 pg l-1 [127,653] by 90-min of light cycling (P = 0.0128). Six 40-s intervals at 100% of V ̇ O 2 peak ${\dot V_{{{\rm{O}}_{\rm{2}}}{\rm{peak}}}}$ increased plasma and serum BDNF, as well as the BDNF-per-platelet ratio 4- to 5-fold more than light exercise did (P ≤ 0.0044). Plasma BDNF was correlated with circulating lactate during the high-intensity intervals (r = 0.47, P = 0.0057), but not during light exercise (P = 0.7407). Changes in cerebral shear stress - whether occurring naturally during exercise or induced experimentally with inspired CO2 - did not correspond with changes in BDNF (P ≥ 0.2730). BDNF responses to low-intensity exercise are mediated by increased circulating platelets, and increasing either exercise duration or particularly intensity is required to liberate free BDNF. KEY POINTS: Intermittent fasting and exercise both have potent neuroprotective effects and an acute upregulation of brain-derived neurotrophic factor (BDNF) appears to be a common mechanistic link. Switching the brain's fuel source from glucose to either ketone bodies or lactate, i.e. a cerebral substrate switch, has been shown to promote BDNF production in the rodent brain. Fasting for 20 h caused a 9-fold increase in ketone body delivery to the brain but had no effect on any metric of BDNF in peripheral circulation at rest. Prolonged (90 min) light cycling exercise increased plasma- and serum-derived BDNF irrespective of being fed or fasted and seemed to be independent of changes in cerebral shear stress. Six minutes of high-intensity cycling intervals increased every metric of circulating BDNF by 4 to 5 times more than prolonged low-intensity cycling; the increase in plasma-derived BDNF was correlated with a 6-fold increase in circulating lactate irrespective of feeding or fasting. Compared to 1 day of fasting with or without prolonged light exercise, high-intensity exercise is a much more efficient means to increase BDNF in circulation.
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Affiliation(s)
- Travis D Gibbons
- School of Physical Education, Sport & Exercise Sciences, University of Otago, Dunedin, New Zealand.,Centre for Heart, Lung and Vascular Health, University of British Columbia - Okanagan, School of Health and Exercise Science, Kelowna, British Columbia, Canada
| | - James D Cotter
- School of Physical Education, Sport & Exercise Sciences, University of Otago, Dunedin, New Zealand
| | - Philip N Ainslie
- Centre for Heart, Lung and Vascular Health, University of British Columbia - Okanagan, School of Health and Exercise Science, Kelowna, British Columbia, Canada
| | - Wickliffe C Abraham
- Department of Psychology, Brain Health Research Centre, University of Otago, Dunedin, New Zealand
| | - Bruce G Mockett
- Department of Psychology, Brain Health Research Centre, University of Otago, Dunedin, New Zealand
| | - Holly A Campbell
- Department of Surgical Sciences, University of Otago, Dunedin, New Zealand
| | - Emma M W Jones
- School of Physical Education, Sport & Exercise Sciences, University of Otago, Dunedin, New Zealand.,Department of Surgical Sciences, University of Otago, Dunedin, New Zealand
| | - Elliott J Jenkins
- School of Physical Education, Sport & Exercise Sciences, University of Otago, Dunedin, New Zealand.,Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, UK
| | - Kate N Thomas
- Department of Surgical Sciences, University of Otago, Dunedin, New Zealand
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23
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Carr JM, Ainslie PN, MacLeod DB, Tremblay JC, Nowak-Flück D, Howe CA, Stembridge M, Patrician A, Coombs GB, Stacey BS, Bailey DM, Green DJ, Hoiland RL. Cerebral O 2 and CO 2 transport in isovolumic haemodilution: Compensation of cerebral delivery of O 2 and maintenance of cerebrovascular reactivity to CO 2. J Cereb Blood Flow Metab 2023; 43:99-114. [PMID: 36131560 PMCID: PMC9875354 DOI: 10.1177/0271678x221119442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
This study investigated the influence of acute reductions in arterial O2 content (CaO2) via isovolumic haemodilution on global cerebral blood flow (gCBF) and cerebrovascular CO2 reactivity (CVR) in 11 healthy males (age; 28 ± 7 years: body mass index; 23 ± 2 kg/m2). Radial artery and internal jugular vein catheters provided measurement of blood pressure and gases, quantification of cerebral metabolism, cerebral CO2 washout, and trans-cerebral nitrite exchange (ozone based chemiluminescence). Prior to and following haemodilution, the partial pressure of arterial CO2 (PaCO2) was elevated with dynamic end-tidal forcing while gCBF was measured with duplex ultrasound. CVR was determined as the slope of the gCBF response and PaCO2. Replacement of ∼20% of blood volume with an equal volume of 5% human serum albumin (Alburex® 5%) reduced haemoglobin (13.8 ± 0.8 vs. 11.3 ± 0.6 g/dL; P < 0.001) and CaO2 (18.9 ± 1.0 vs 15.0 ± 0.8 mL/dL P < 0.001), elevated gCBF (+18 ± 11%; P = 0.002), preserved cerebral oxygen delivery (P = 0.49), and elevated CO2 washout (+11%; P = 0.01). The net cerebral uptake of nitrite (11.6 ± 14.0 nmol/min; P = 0.027) at baseline was abolished following haemodilution (-3.6 ± 17.9 nmol/min; P = 0.54), perhaps underpinning the conservation of CVR (61.7 ± 19.0 vs. 69.0 ± 19.2 mL/min/mmHg; P = 0.23). These findings demonstrate that the cerebrovascular responses to acute anaemia in healthy humans are sufficient to support the maintenance of CVR.
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Affiliation(s)
- Jay Mjr Carr
- Centre for Heart, Lung and Vascular Health, University of British Columbia - Okanagan Campus, School of Health and Exercise Sciences, Kelowna, B.C., Canada, V1V 1V7
| | - Philip N Ainslie
- Centre for Heart, Lung and Vascular Health, University of British Columbia - Okanagan Campus, School of Health and Exercise Sciences, Kelowna, B.C., Canada, V1V 1V7
| | - David B MacLeod
- Human Pharmacology & Physiology Lab, Department of Anesthesiology, Duke University Medical Center, Durham, NC, USA
| | - Joshua C Tremblay
- Centre for Heart, Lung and Vascular Health, University of British Columbia - Okanagan Campus, School of Health and Exercise Sciences, Kelowna, B.C., Canada, V1V 1V7
| | - Daniela Nowak-Flück
- Centre for Heart, Lung and Vascular Health, University of British Columbia - Okanagan Campus, School of Health and Exercise Sciences, Kelowna, B.C., Canada, V1V 1V7
| | - Connor A Howe
- Centre for Heart, Lung and Vascular Health, University of British Columbia - Okanagan Campus, School of Health and Exercise Sciences, Kelowna, B.C., Canada, V1V 1V7
| | - Mike Stembridge
- Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, UK
| | - Alexander Patrician
- Centre for Heart, Lung and Vascular Health, University of British Columbia - Okanagan Campus, School of Health and Exercise Sciences, Kelowna, B.C., Canada, V1V 1V7
| | - Geoff B Coombs
- Centre for Heart, Lung and Vascular Health, University of British Columbia - Okanagan Campus, School of Health and Exercise Sciences, Kelowna, B.C., Canada, V1V 1V7.,School of Kinesiology, Faculty of Health Sciences, University of Western Ontario, London, Ontario, Canada
| | - Benjamin S Stacey
- Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, Pontypridd, UK
| | - Damian M Bailey
- Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, Pontypridd, UK
| | - Daniel J Green
- School of Human Sciences (Exercise and Sport Sciences), The University of Western Australia, Nedlands, Western Australia
| | - Ryan L Hoiland
- Centre for Heart, Lung and Vascular Health, University of British Columbia - Okanagan Campus, School of Health and Exercise Sciences, Kelowna, B.C., Canada, V1V 1V7.,Department of Anesthesiology, Pharmacology and Therapeutics, Faculty of Medicine, Vancouver General Hospital, University of British Columbia, Vancouver, BC, Canada.,Department of Cellular and Physiological Sciences, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada.,International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, British Columbia, Canada
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24
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Subedi P, Gasho C, Stembridge M, Williams AM, Patrician A, Ainslie PN, Anholm JD. Pulmonary vascular reactivity to supplemental oxygen in Sherpa and lowlanders during gradual ascent to high altitude. Exp Physiol 2023; 108:111-122. [PMID: 36404588 PMCID: PMC10103769 DOI: 10.1113/ep090458] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Accepted: 10/18/2022] [Indexed: 11/23/2022]
Abstract
NEW FINDINGS What is the central question of this study? How does hypoxic pulmonary vasoconstriction and the response to supplemental oxygen change over time at high altitude? What is the main finding and its importance? Lowlanders and partially de-acclimatized Sherpa both demonstrated pulmonary vascular responsiveness to supplemental oxygen that was maintained for 12 days' exposure to progressively increasing altitude. An additional 2 weeks' acclimatization at 5050 m altitude rendered the pulmonary vasculature minimally responsive to oxygen similar to the fully acclimatized non-ascent Sherpa. Additional hypoxic exposure at that time point did not augment hypoxic pulmonary vasoconstriction. ABSTRACT Prolonged alveolar hypoxia leads to pulmonary vascular remodelling. We examined the time course at altitude, over which hypoxic pulmonary vasoconstriction goes from being acutely reversible to potentially irreversible. Study subjects were lowlanders (n = 20) and two Sherpa groups. All Sherpa were born and raised at altitude. One group (ascent Sherpa, n = 11) left altitude and after de-acclimatization in Kathmandu for ∼7 days re-ascended with the lowlanders over 8-10 days to 5050 m. The second Sherpa group (non-ascent Sherpa, n = 12) remained continuously at altitude. Pulmonary artery systolic pressure (PASP) and pulmonary vascular resistance (PVR) were measured while breathing ambient air and following supplemental oxygen. During ascent PASP and PVR increased in lowlanders and ascent Sherpa; however, with supplemental oxygen, lowlanders had significantly greater decrease in PASP (P = 0.02) and PVR (P = 0.02). After ∼14 days at 5050 m, PASP decreased with supplemental oxygen (mean decrease: 3.9 mmHg, 95% CI 2.1-5.7 mmHg, P < 0.001); however, PVR was unchanged (P = 0.49). In conclusion, PASP and PVR increased with gradual ascent to altitude and decreased via oxygen supplementation in both lowlanders and ascent Sherpa. Following ∼14 days at 5050 m altitude, there was no change in PVR to hypoxia or O2 supplementation in lowlanders or either Sherpa group. These data show that both duration of exposure and residential altitude influence the pulmonary vascular responses to hypoxia.
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Affiliation(s)
- Prajan Subedi
- Division of PulmonaryCritical Care, Sleep, Hyperbaric Medicine and AllergyDept. of MedicineLoma Linda University School of MedicinePulmonary SectionVA Loma Linda Healthcare SystemLoma LindaCaliforniaUSA
| | - Christopher Gasho
- Division of PulmonaryCritical Care, Sleep, Hyperbaric Medicine and AllergyDept. of MedicineLoma Linda University School of MedicinePulmonary SectionVA Loma Linda Healthcare SystemLoma LindaCaliforniaUSA
| | - Michael Stembridge
- Cardiff School of Sport and Health SciencesCardiff Metropolitan UniversityCardiffUK
| | - Alexandra M. Williams
- Department of Cellular and Physiological SciencesFaculty of MedicineUniversity of British ColumbiaVancouverBCCanada
| | - Alexander Patrician
- Centre for Heart, Lung and Vascular HealthFaculty of Health and Social DevelopmentUniversity of British Columbia – OkanaganKelownaBCCanada
| | - Philip N. Ainslie
- Centre for Heart, Lung and Vascular HealthFaculty of Health and Social DevelopmentUniversity of British Columbia – OkanaganKelownaBCCanada
| | - James D. Anholm
- Division of PulmonaryCritical Care, Sleep, Hyperbaric Medicine and AllergyDept. of MedicineLoma Linda University School of MedicinePulmonary SectionVA Loma Linda Healthcare SystemLoma LindaCaliforniaUSA
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25
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Sarafis ZK, Squair JW, Barak OF, Coombs GB, Soriano JE, Larkin-Kaiser KA, Lee AHX, Hansen A, Vodopic M, Romac R, Grant C, Charbonneau R, Mijacika T, Krassioukov AV, Ainslie PN, Dujic Z, Phillips AA. Common carotid artery responses to the cold-pressor test are impaired in individuals with cervical spinal cord injury. Am J Physiol Heart Circ Physiol 2022; 323:H1311-H1322. [PMID: 36367686 DOI: 10.1152/ajpheart.00261.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Cervical spinal cord injury (SCI) leads to autonomic cardiovascular dysfunction that underlies the three- to fourfold elevated risk of cardiovascular disease in this population. Reduced common carotid artery (CCA) dilatory responsiveness during the cold-pressor test (CPT) is associated with greater cardiovascular disease risk and progression. The cardiovascular and CCA responses to the CPT may provide insight into cardiovascular autonomic dysfunction and cardiovascular disease risk in individuals with cervical SCI. Here, we used CPT to perturb the autonomic nervous system in 14 individuals with cervical SCI and 12 uninjured controls, while measuring cardiovascular responses and CCA diameter. The CCA diameter responses were 55% impaired in those with SCI compared with uninjured controls (P = 0.019). The CCA flow, velocity, and shear response to CPT were reduced in SCI by 100% (P < 0.001), 113% (P = 0.001), and 125% (P = 0.002), respectively. The association between mean arterial pressure and CCA dilation observed in uninjured individuals (r = 0.54, P = 0.004) was absent in the SCI group (r = 0.22, P = 0.217). Steady-state systolic blood pressure (P = 0.020), heart rate (P = 0.003), and cardiac contractility (P < 0.001) were reduced in those with cervical SCI, whereas total peripheral resistance was increased compared with uninjured controls (P = 0.042). Relative cerebral blood velocity responses to CPT were increased in the SCI group and reduced in controls (middle cerebral artery, P = 0.010; posterior cerebral artery, P = 0.026). The CCA and cardiovascular responsiveness to CPT are impaired in those with cervical SCI.NEW & NOTEWORTHY This is the first study demonstrating that CCA responses during CPT are suppressed in SCI. Specifically, CCA diameter, flow, velocity, and shear rate were reduced. The relationship between changes in MAP and CCA dilatation in response to CPT was absent in individuals with SCI, despite similar cardiovascular activation between SCI and uninjured controls. These findings support the notion of elevated cardiovascular disease risk in SCI and that the cardiovascular responses to environmental stimuli are impaired.
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Affiliation(s)
- Zoe K Sarafis
- International Collaboration on Repair Discoveries, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Jordan W Squair
- International Collaboration on Repair Discoveries, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada.,RESTORE.network, Departments of Physiology and Pharmacology, Cardiac Sciences and Clinical Neurosciences, Biomedical Engineering, Libin Cardiovascular Institute of Alberta, Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada.,MD/PhD Training Program, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada.,Department of Experimental Medicine, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Otto F Barak
- Faculty of Medicine, University of Novi Sad, Novi Sad, Serbia
| | - Geoff B Coombs
- Centre for Heart, Lung and Vascular Health, University of British Columbia Okanagan, Kelowna, British Columbia, Canada
| | - Jan Elaine Soriano
- RESTORE.network, Departments of Physiology and Pharmacology, Cardiac Sciences and Clinical Neurosciences, Biomedical Engineering, Libin Cardiovascular Institute of Alberta, Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada
| | - Kelly A Larkin-Kaiser
- RESTORE.network, Departments of Physiology and Pharmacology, Cardiac Sciences and Clinical Neurosciences, Biomedical Engineering, Libin Cardiovascular Institute of Alberta, Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada
| | - Amanda H X Lee
- International Collaboration on Repair Discoveries, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada.,Department of Experimental Medicine, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Alex Hansen
- Department of Sport Science, University of Innsbruck, Innsbruck, Austria
| | - Maro Vodopic
- Department of Neurology, General Hospital, Dubrovnik, Croatia
| | - Rinaldo Romac
- Department of Neurology, Clinical Hospital Center, Split, Croatia
| | - Christopher Grant
- Division of Physical Medicine and Rehabilitation, Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Rebecca Charbonneau
- Division of Physical Medicine and Rehabilitation, Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Tanja Mijacika
- Department of Integrative Physiology, University of Split School of Medicine, Split, Croatia
| | - Andrei V Krassioukov
- International Collaboration on Repair Discoveries, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada.,Division of Physical Medicine and Rehabilitation, University of British Columbia, Vancouver, British Columbia, Canada.,GF Strong Rehabilitation Centre, Vancouver, British Columbia, Canada
| | - Philip N Ainslie
- Centre for Heart, Lung and Vascular Health, University of British Columbia Okanagan, Kelowna, British Columbia, Canada
| | - Zeljko Dujic
- Department of Integrative Physiology, University of Split School of Medicine, Split, Croatia
| | - Aaron A Phillips
- RESTORE.network, Departments of Physiology and Pharmacology, Cardiac Sciences and Clinical Neurosciences, Biomedical Engineering, Libin Cardiovascular Institute of Alberta, Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada
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26
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Carr JMJR, Howe CA, Gibbons TD, Tymko MM, Steele AR, Vizcardo-Galindo GA, Tremblay JC, Ainslie PN. Cerebral endothelium-dependent function and reactivity to hypercapnia: the role of α 1-adrenoreceptors. J Appl Physiol (1985) 2022; 133:1356-1367. [PMID: 36326471 DOI: 10.1152/japplphysiol.00400.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
We assessed hypercapnic cerebrovascular reactivity (CVR) and endothelium-dependent function [cerebral shear-mediated dilation (cSMD)] in the internal carotid artery (ICA) with and without systemic α1-adrenoreceptor blockade via Prazosin. We hypothesized that CVR would be reduced, whereas cSMD would remain unchanged, after Prazosin administration when compared with placebo. In 15 healthy adults (3 female, 26 ± 4 years), we conducted ICA duplex ultrasound during CVR [target +10 mmHg partial pressure of end-tidal carbon dioxide ([Formula: see text]) above baseline, 5 min] and cSMD (+9 mmHg [Formula: see text] above baseline, 30 s) using dynamic end-tidal forcing with and without α1-adrenergic blockade (Prazosin; 0.05 mg/kg) in a placebo-controlled, double-blind, and randomized design. The CVR in the ICA was not different between placebo and Prazosin (P = 0.578). During CVR, the reactivities of mean arterial pressure and cerebrovascular conductance to hypercapnia were also not different between conditions (P = 0.921 and P = 0.664, respectively). During Prazosin, cSMD was lower (1.1 ± 2.0% vs 3.8 ± 3.0%; P = 0.032); however, these data should be interpreted with caution due to the elevated baseline diameter (+1.3 ± 3.6%; condition: P = 0.0498) and lower shear rate (-14.5 ± 23.0%; condition: P < 0.001). Therefore, lower cSMD post α1-adrenoreceptor blockade might not indicate a reduction in cerebral endothelial function per se, but rather, that α1-adrenoreceptors contribute to resting cerebral vascular restraint at the level of the ICA.NEW & NOTEWORTHY We assessed steady-state hypercapnic cerebrovascular reactivity and cerebral endothelium-dependent function, with and without α1-adrenergic blockade (Prazosin), in a placebo-controlled, double-blind, and randomized study, to assess the contribution of α1-adrenergic receptors to cerebrovascular CO2 regulation. After administration of Prazosin, cerebrovascular reactivity to CO2 was not different compared with placebo despite lower blood flow, whereas cerebral endothelium-dependent function was reduced, likely due to elevated baseline internal carotid arterial diameter. These findings suggest that α1-adrenoreceptor activity does not influence cerebral blood flow regulation to CO2 and cerebral endothelial function.
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Affiliation(s)
- Jay M J R Carr
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan Campus, Kelowna, British Columbia, Canada
| | - Connor A Howe
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan Campus, Kelowna, British Columbia, Canada
| | - Travis D Gibbons
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan Campus, Kelowna, British Columbia, Canada
| | - Michael M Tymko
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan Campus, Kelowna, British Columbia, Canada.,Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Edmonton, Alberta, Canada.,Department of Medicine, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Andrew R Steele
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan Campus, Kelowna, British Columbia, Canada
| | - Gustavo A Vizcardo-Galindo
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan Campus, Kelowna, British Columbia, Canada
| | - Joshua C Tremblay
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan Campus, Kelowna, British Columbia, Canada
| | - Philip N Ainslie
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan Campus, Kelowna, British Columbia, Canada
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27
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Carr JMJR, Ainslie PN, Howe CA, Gibbons TD, Tymko MM, Steele AR, Hoiland RL, Vizcardo-Galindo GA, Patrician A, Brown CV, Caldwell HG, Tremblay JC. Brachial artery responses to acute hypercapnia: The roles of shear stress and adrenergic tone. Exp Physiol 2022; 107:1440-1453. [PMID: 36114662 DOI: 10.1113/ep090690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Accepted: 09/12/2022] [Indexed: 12/14/2022]
Abstract
NEW FINDINGS What is the central question of this study? What are the contributions of shear stress and adrenergic tone to brachial artery vasodilatation during hypercapnia? What is the main finding and its importance? In healthy young adults, shear-mediated vasodilatation does not occur in the brachial artery during hypercapnia, as elevated α₁-adrenergic activity typically maintains vascular tone and offsets distal vasodilatation controlling flow. ABSTRACT We aimed to assess the shear stress dependency of brachial artery (BA) responses to hypercapnia, and the α₁-adrenergic restraint of these responses. We hypothesized that elevated shear stress during hypercapnia would cause BA vasodilatation, but where shear stress was prohibited (via arterial compression), the BA would not vasodilate (study 1); and, in the absence of α₁-adrenergic activity, blood flow, shear stress and BA vasodilatation would increase (study 2). In study 1, 14 healthy adults (7/7 male/female, 27 ± 4 years) underwent bilateral BA duplex ultrasound during hypercapnia (partial pressure of end-tidal carbon dioxide, +10.2 ± 0.3 mmHg above baseline, 12 min) via dynamic end-tidal forcing, and shear stress was reduced in one BA using manual compression (compression vs. control arm). Neither diameter nor blood flow was different between baseline and the last minute of hypercapnia (P = 0.423, P = 0.363, respectively) in either arm. The change values from baseline to the last minute, in diameter (%; P = 0.201), flow (ml/min; P = 0.234) and conductance (ml/min/mmHg; P = 0.503) were not different between arms. In study 2, 12 healthy adults (9/3 male/female, 26 ± 4 years) underwent the same design with and without α₁-adrenergic receptor blockade (prazosin; 0.05 mg/kg) in a placebo-controlled, double-blind and randomized design. BA flow, conductance and shear rate increased during hypercapnia in the prazosin control arm (interaction, P < 0.001), but in neither arm during placebo. Even in the absence of α₁-adrenergic restraint, downstream vasodilatation in the microvasculature during hypercapnia is insufficient to cause shear-mediated vasodilatation in the BA.
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Affiliation(s)
- Jay M J R Carr
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan Campus, Kelowna, BC, Canada
| | - Philip N Ainslie
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan Campus, Kelowna, BC, Canada
| | - Connor A Howe
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan Campus, Kelowna, BC, Canada
| | - Travis D Gibbons
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan Campus, Kelowna, BC, Canada
| | - Michael M Tymko
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan Campus, Kelowna, BC, Canada.,Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Edmonton, Canada.,Faculty of Medicine, Department of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Andrew R Steele
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan Campus, Kelowna, BC, Canada
| | - Ryan L Hoiland
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan Campus, Kelowna, BC, Canada
| | - Gustavo A Vizcardo-Galindo
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan Campus, Kelowna, BC, Canada
| | - Alex Patrician
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan Campus, Kelowna, BC, Canada
| | - Courtney V Brown
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan Campus, Kelowna, BC, Canada
| | - Hannah G Caldwell
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan Campus, Kelowna, BC, Canada
| | - Joshua C Tremblay
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan Campus, Kelowna, BC, Canada
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28
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Gibbons TD, Dempsey JA, Thomas KN, Ainslie PN, Wilson LC, Stothers TAM, Campbell HA, Cotter JD. Carotid body hyperexcitability underlies heat-induced hyperventilation in exercising humans. J Appl Physiol (1985) 2022; 133:1394-1406. [PMID: 36302157 DOI: 10.1152/japplphysiol.00435.2022] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Physical activity is the most common source of heat strain for humans. The thermal strain of physical activity causes overbreathing (hyperventilation) and this has adverse physiological repercussions. The mechanisms underlying heat-induced hyperventilation during exercise are unknown, but recent evidence supports a primary role of carotid body hyperexcitability (increased tonic activity and sensitivity) underpinning hyperventilation in passively heated humans. In a repeated-measures crossover design, 12 healthy participants (6 female) completed two low-intensity cycling exercise conditions (25% maximal aerobic power) in randomized order, one with core temperature (TC) kept relatively stable near thermoneutrality, and the other with progressive heat strain to +2°C TC. To provide a complete examination of carotid body function under graded heat strain, carotid body tonic activity was assessed indirectly by transient hyperoxia, and its sensitivity estimated by responses to both isocapnic and poikilocapnic hypoxia. Carotid body tonic activity was increased by 220 ± 110% during cycling alone, and by 400 ± 290% with supplemental thermal strain to +1°C TC, and 600 ± 290% at +2°C TC (interaction, P = 0.0031). During exercise with heat stress at both +1°C and +2°C TC, carotid body suppression by hyperoxia decreased ventilation below the rates observed during exercise without heat stress (P < 0.0147). Carotid body sensitivity was increased by up to 230 ± 190% with exercise alone, and by 290 ± 250% with supplemental heating to +1°C TC and 510 ± 470% at +2°C TC (interaction, P = 0.0012). These data indicate that the carotid body is further activated and sensitized by heat strain during exercise and this largely explains the added drive to breathe.NEW & NOTEWORTHY Physical activity is the most common way humans increase their core temperature, and excess breathing in the heat can limit heat tolerance and performance, and may increase the risk of heat-related injury. Dose-dependent increases in carotid body tonic activity and sensitivity with core heating provide compelling evidence that carotid body hyperexcitability is the primary cause of heat-induced hyperventilation during exercise.
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Affiliation(s)
- Travis D Gibbons
- Centre for Heart, Lung and Vascular Health, University of British Columbia-Okanagan, School of Health and Exercise Science, Kelowna, British Columbia, Canada
| | - Jerome A Dempsey
- John Rankin Laboratory for Pulmonary Medicine, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin
| | - Kate N Thomas
- Department of Surgical Sciences, University of Otago, Dunedin, New Zealand
| | - Philip N Ainslie
- Centre for Heart, Lung and Vascular Health, University of British Columbia-Okanagan, School of Health and Exercise Science, Kelowna, British Columbia, Canada
| | - Luke C Wilson
- Department of Medicine, University of Otago, Dunedin, New Zealand
| | - Tiarna A M Stothers
- School of Physical Education, Sport & Exercise Sciences, University of Otago, Dunedin, New Zealand
| | - Holly A Campbell
- Department of Surgical Sciences, University of Otago, Dunedin, New Zealand
| | - James D Cotter
- School of Physical Education, Sport & Exercise Sciences, University of Otago, Dunedin, New Zealand
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29
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Yamada Y, Zhang X, Henderson MET, Sagayama H, Pontzer H, Watanabe D, Yoshida T, Kimura M, Ainslie PN, Andersen LF, Anderson LJ, Arab L, Baddou I, Bedu-Addo K, Blaak EE, Blanc S, Bonomi AG, Bouten CVC, Bovet P, Buchowski MS, Butte NF, Camps SG, Close GL, Cooper JA, Cooper R, Das SK, Dugas LR, Eaton S, Ekelund U, Entringer S, Forrester T, Fudge BW, Goris AH, Gurven M, Halsey LG, Hambly C, El Hamdouchi A, Hoos MB, Hu S, Joonas N, Joosen AM, Katzmarzyk P, Kempen KP, Kraus WE, Kriengsinyos W, Kushner RF, Lambert EV, Leonard WR, Lessan N, Martin CK, Medin AC, Meijer EP, Morehen JC, Morton JP, Neuhouser ML, Nicklas TA, Ojiambo RM, Pietiläinen KH, Pitsiladis YP, Plange-Rhule J, Plasqui G, Prentice RL, Rabinovich RA, Racette SB, Raichlen DA, Ravussin E, Redman LM, Reilly JJ, Reynolds RM, Roberts SB, Schuit AJ, Sardinha LB, Silva AM, Sjödin AM, Stice E, Urlacher SS, Valenti G, Van Etten LM, Van Mil EA, Wells JCK, Wilson G, Wood BM, Yanovski JA, Murphy-Alford AJ, Loechl CU, Luke AH, Rood J, Westerterp KR, Wong WW, Miyachi M, Schoeller DA, Speakman JR. Variation in human water turnover associated with environmental and lifestyle factors. Science 2022; 378:909-915. [PMID: 36423296 PMCID: PMC9764345 DOI: 10.1126/science.abm8668] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Water is essential for survival, but one in three individuals worldwide (2.2 billion people) lacks access to safe drinking water. Water intake requirements largely reflect water turnover (WT), the water used by the body each day. We investigated the determinants of human WT in 5604 people from the ages of 8 days to 96 years from 23 countries using isotope-tracking (2H) methods. Age, body size, and composition were significantly associated with WT, as were physical activity, athletic status, pregnancy, socioeconomic status, and environmental characteristics (latitude, altitude, air temperature, and humidity). People who lived in countries with a low human development index (HDI) had higher WT than people in high-HDI countries. On the basis of this extensive dataset, we provide equations to predict human WT in relation to anthropometric, economic, and environmental factors.
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Affiliation(s)
- Yosuke Yamada
- National Institute of Health and Nutrition, National Institutes of Biomedical Innovation, Health and Nutrition, Osaka, Japan
- Institute for Active Health, Kyoto University of Advanced Science, Kyoto, Japan
| | - Xueying Zhang
- Shenzhen Key Laboratory of Metabolic Health, Center for Energy Metabolism and Reproduction, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
- Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, UK
| | - Mary E T Henderson
- School of Life and Health Sciences, University of Roehampton, London, UK
| | - Hiroyuki Sagayama
- Faculty of Health and Sport Sciences, University of Tsukuba, Ibaraki, Japan
| | - Herman Pontzer
- Department of Evolutionary Anthropology, Duke University, Durham, NC, USA
- Duke Global Health Institute, Duke University, Durham, NC, USA
| | - Daiki Watanabe
- National Institute of Health and Nutrition, National Institutes of Biomedical Innovation, Health and Nutrition, Osaka, Japan
- Institute for Active Health, Kyoto University of Advanced Science, Kyoto, Japan
- Faculty of Sport Sciences, Waseda University, Saitama, Japan
| | - Tsukasa Yoshida
- National Institute of Health and Nutrition, National Institutes of Biomedical Innovation, Health and Nutrition, Osaka, Japan
- Institute for Active Health, Kyoto University of Advanced Science, Kyoto, Japan
| | - Misaka Kimura
- Institute for Active Health, Kyoto University of Advanced Science, Kyoto, Japan
| | - Philip N Ainslie
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, Faculty of Health and Social Development, University of British Columbia Okanagan, Kelowna, British Columbia, Canada
| | - Lene F Andersen
- Department of Nutrition, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Liam J Anderson
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, UK
| | - Lenore Arab
- David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - Issad Baddou
- Unité Mixte de Recherche en Nutrition et Alimentation, CNESTEN-Université Ibn Tofail URAC39, Regional Designated Center of Nutrition Associated with AFRA/IAEA, Rabat, Morocco
| | - Kweku Bedu-Addo
- Department of Physiology, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Ellen E Blaak
- Department of Human Biology, Maastricht University, Maastricht, Netherlands
| | - Stephane Blanc
- Nutritional Sciences, University of Wisconsin, Madison, WI, USA
- Institut Pluridisciplinaire Hubert Curien, CNRS Université de Strasbourg, UMR7178, France
| | | | | | - Pascal Bovet
- University Center for Primary Care and Public Health (Unisanté), Lausanne, Switzerland
| | - Maciej S Buchowski
- Division of Gastroenterology, Hepatology and Nutrition, Department of Medicine, Vanderbilt University, Nashville, TN, USA
| | - Nancy F Butte
- Department of Pediatrics, Baylor College of Medicine, US Department of Agriculture (USDA)/Agricultural Research Service (ARS) Children's Nutrition Research Center, Houston, TX, USA
| | - Stefan G Camps
- Maastricht University, Maastricht, Netherlands
- Clinical Nutrition Research Centre (CNRC), Singapore Institute of Food and Biotechnology Innovation (SIFBI), Agency of Science, Technology and Research (A*STAR), Singapore
| | - Graeme L Close
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK
| | - Jamie A Cooper
- Nutritional Sciences, University of Georgia, Athens, GA, USA
| | - Richard Cooper
- Department of Public Health Sciences, Parkinson School of Health Sciences and Public Health, Loyola University, Maywood, IL, USA
| | - Sai Krupa Das
- USDA Human Nutrition Research Center on Aging at Tufts University, Boston, MA, USA
| | - Lara R Dugas
- Public Health Sciences, Loyola University of Chicago, Maywood, IL, USA
- Division of Epidemiology and Biostatistics, School of Public Health & Family Medicine, University of Cape Town, Cape Town, South Africa
| | - Simon Eaton
- Developmental Biology and Cancer Department, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Ulf Ekelund
- Department of Sport Medicine, Norwegian School of Sport Sciences, Oslo, Norway
- Department of Chronic Diseases, Norwegian Institute of Public Health, Oslo, Norway
| | - Sonja Entringer
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Institute of Medical Psychology, Berlin, Germany
- Department of Pediatrics, University of California Irvine, Irvine, CA, USA
| | - Terrence Forrester
- Solutions for Developing Countries, University of the West Indies, Mona, Kingston, Jamaica
| | | | | | - Michael Gurven
- Department of Anthropology, University of California Santa Barbara, Santa Barbara, CA, USA
| | - Lewis G Halsey
- School of Life and Health Sciences, University of Roehampton, London, UK
| | - Catherine Hambly
- Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, UK
| | - Asmaa El Hamdouchi
- Unité Mixte de Recherche en Nutrition et Alimentation, CNESTEN-Université Ibn Tofail URAC39, Regional Designated Center of Nutrition Associated with AFRA/IAEA, Rabat, Morocco
| | | | - Sumei Hu
- Beijing Technology and Business University, Beijing, China
| | - Noorjehan Joonas
- Central Health Laboratory, Ministry of Health and Wellness, Mauritius
| | | | | | | | | | - Wantanee Kriengsinyos
- Institute of Nutrition, Mahidol University, Salaya, Phutthamonthon, Nakon-Pathom, Thailand
| | - Robert F Kushner
- Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Estelle V Lambert
- Health Through Physical Activity, Lifestyle and Sport Research Centre (HPALS) Division of Exercise Science and Sports Medicine (ESSM), FIMS International Collaborating Centre of Sports Medicine, Department of Human Biology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - William R Leonard
- Department of Anthropology, Northwestern University, Evanston, IL, USA
| | - Nader Lessan
- Imperial College London Diabetes Centre, Abu Dhabi, United Arab Emirates
- Imperial College London, London, UK
| | - Corby K Martin
- Pennington Biomedical Research Center, Baton Rouge, LA, USA
| | - Anine C Medin
- Department of Nutrition, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
- Department of Nutrition and Public Health, Faculty of Health and Sport Sciences, University of Agder, Kristiansand, Norway
| | | | - James C Morehen
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK
- The FA Group, Burton-Upon-Trent, Staffordshire, UK
| | - James P Morton
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK
| | - Marian L Neuhouser
- Division of Public Health Sciences, Fred Hutchinson Cancer Center and School of Public Health, University of Washington, Seattle, WA, USA
| | - Theresa A Nicklas
- Department of Pediatrics, Baylor College of Medicine, US Department of Agriculture (USDA)/Agricultural Research Service (ARS) Children's Nutrition Research Center, Houston, TX, USA
| | - Robert M Ojiambo
- Kenya School of Medicine, Moi University, Eldoret, Kenya
- Rwanda Division of Basic Sciences, University of Global Health Equity, Rwanda
| | - Kirsi H Pietiläinen
- Obesity Research Unit, Research Program for Clinical and Molecular Metabolism, Faculty of Medicine, University of Helsinki, and Abdominal Center, Obesity Center, HealthyWeightHub, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
| | - Yannis P Pitsiladis
- School of Sport and Service Management, University of Brighton, Eastbourne, UK
| | - Jacob Plange-Rhule
- Department of Physiology, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Guy Plasqui
- Department of Nutrition and Movement Sciences, Maastricht University, Maastricht, Netherlands
| | - Ross L Prentice
- Division of Public Health Sciences, Fred Hutchinson Cancer Center and School of Public Health, University of Washington, Seattle, WA, USA
| | | | - Susan B Racette
- Program in Physical Therapy and Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA, and College of Health Solutions, Arizona State University, Phoenix, AZ, USA
| | - David A Raichlen
- Biological Sciences and Anthropology, University of Southern California, Los Angeles, CA, USA
| | - Eric Ravussin
- Pennington Biomedical Research Center, Baton Rouge, LA, USA
| | | | | | - Rebecca M Reynolds
- Centre for Cardiovascular Sciences, Queen's Medical Research Institute, University of Edinburgh, Edinburgh, UK
| | - Susan B Roberts
- USDA Human Nutrition Research Center on Aging at Tufts University, Boston, MA, USA
| | - Albertine J Schuit
- School of Social and Behavioral Sciences, University of Tilburg, Tilburg, Netherlands
| | - Luis B Sardinha
- Exercise and Health Laboratory, CIPER, Faculdade Motricidade Humana, Universidade de Lisboa, Portugal
| | - Analiza M Silva
- Exercise and Health Laboratory, CIPER, Faculdade Motricidade Humana, Universidade de Lisboa, Portugal
| | - Anders M Sjödin
- Department of Nutrition, Exercise and Sports, Copenhagen University, Copenhagen, Denmark
| | - Eric Stice
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, USA
| | - Samuel S Urlacher
- Department of Anthropology, Baylor University, Waco, TX, USA
- Child and Brain Development Program, Canadian Institute for Advanced Research (CIFAR), Toronto, Ontario, Canada
| | - Giulio Valenti
- Phillips Research, Eindoven, Netherlands
- Maastricht University, Maastricht, Netherlands
| | | | - Edgar A Van Mil
- Maastricht University, Brightlands Campus Greenport Venlo and Lifestyle Medicine Center for Children, Jeroen Bosch Hospital, Hertogenbosch, Netherlands
| | - Jonathan C K Wells
- Population, Policy and Practice Research and Teaching Department, UCL Great Ormond Street Institute of Child Health, London, UK
| | - George Wilson
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK
| | - Brian M Wood
- Department of Anthropology, University of California Los Angeles, Los Angeles, CA, USA
- Max Planck Institute for Evolutionary Anthropology, Department of Human Behavior, Ecology, and Culture, Leipzig, Germany
| | - Jack A Yanovski
- Section on Growth and Obesity, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Alexia J Murphy-Alford
- Nutritional and Health-Related Environmental Studies Section, Division of Human Health, International Atomic Energy Agency, Vienna, Austria
| | - Cornelia U Loechl
- Nutritional and Health-Related Environmental Studies Section, Division of Human Health, International Atomic Energy Agency, Vienna, Austria
| | - Amy H Luke
- Department of Public Health Sciences, Parkinson School of Health Sciences and Public Health, Loyola University Chicago, Chicago, IL, USA
| | - Jennifer Rood
- Pennington Biomedical Research Center, Baton Rouge, LA, USA
| | | | - William W Wong
- Department of Pediatrics, Baylor College of Medicine, US Department of Agriculture (USDA)/Agricultural Research Service (ARS) Children's Nutrition Research Center, Houston, TX, USA
| | - Motohiko Miyachi
- National Institute of Health and Nutrition, National Institutes of Biomedical Innovation, Health and Nutrition, Osaka, Japan
- Faculty of Sport Sciences, Waseda University, Saitama, Japan
| | - Dale A Schoeller
- Biotechnology Center and Department of Nutritional Sciences, University of Wisconsin, Madison, WI, USA
| | - John R Speakman
- Shenzhen Key Laboratory of Metabolic Health, Center for Energy Metabolism and Reproduction, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
- Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, UK
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
- CAS Center of Excellence in Animal Evolution and Genetics, Kunming, China
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30
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Rieger MG, Tallon CM, Perkins DR, Smith KJ, Stembridge M, Piombo S, Radom-Aizik S, Cooper DM, Ainslie PN, McManus AM. Cardiopulmonary and cerebrovascular acclimatization in children and adults at 3800 m. J Physiol 2022; 600:4849-4863. [PMID: 36165275 DOI: 10.1113/jp283419] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Accepted: 09/20/2022] [Indexed: 12/24/2022] Open
Abstract
Maturational differences exist in cardiopulmonary and cerebrovascular function at sea-level, but the impact of maturation on acclimatization responses to high altitude is unknown. Ten children (9.8 ± 2.5 years) and 10 adults (34.7 ± 7.1 years) were assessed at sea-level (BL), 3000 m and twice over 4 days at 3800 m (B1, B4). Measurements included minute ventilation ( V ̇ E ${\dot{V}}_{\rm{E}}$ ), end-tidal partial pressures of oxygen ( P ETO 2 ${P}_{{\rm{ETO}}_{\rm{2}}}$ ) and carbon dioxide, echocardiographic assessment of pulmonary artery systolic pressure (PASP) and stroke volume (SV) and ultrasound assessment of blood flow through the internal carotid and vertebral arteries was performed to calculate global cerebral blood flow (gCBF). At 3000 m, V ̇ E ${\dot{V}}_{\rm{E}}$ was increased from BL by 19.6 ± 19.1% (P = 0.031) in children, but not in adults (P = 0.835); SV was reduced in children (-11 ± 13%, P = 0.020) but not adults (P = 0.827), which was compensated for by a larger increase in heart rate in children (+26 beats min-1 vs. +13 beats min-1 , P = 0.019). Between B1 and B4, adults increased V ̇ E ${\dot{V}}_{\rm{E}}$ by 38.5 ± 34.7% (P = 0.006), while V ̇ E ${\dot{V}}_{\rm{E}}$ did not increase further in children. The rise in PASP was not different between groups; however, ∆PASP from BL was related to ∆ P ETO 2 ${P}_{{\rm{ETO}}_{\rm{2}}}$ in adults (R2 = 0.288, P = 0.022), but not children. At BL, gCBF was 43% higher in children than adults (P = 0.017), and this difference was maintained at high altitude, with a similar pattern and magnitude of change in gCBF between groups (P = 0.845). Despite V ̇ E ${\dot{V}}_{\rm{E}}$ increasing in children but not adults at a lower altitude, the pulmonary vascular and cerebrovascular responses to prolonged hypoxia are similar between children and adults. KEY POINTS: Children have different ventilatory and metabolic requirements from adults, which may present differently in the pulmonary and cerebral vasculature upon ascent to high altitude. Children (ages 7-14) and adults (ages 23-44) were brought from sea level to high altitude (3000 to 3800 m) and changes in ventilation, pulmonary artery systolic pressure (PASP) and cerebral blood flow (CBF) were assessed over 1 week. Significant increases in ventilation and decreases in left ventricle stroke volume were observed at a lower altitude in children than adults. PASP and CBF increased by a similar relative amount between children and adults at 3800 m. These results help us better understand age-related differences in compensatory responses to prolonged hypoxia in children, despite similar changes in pulmonary artery pressure and CBF between children and adults.
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Affiliation(s)
- M G Rieger
- Centre for Heart, Lung & Vascular Health, University of British Columbia, Kelowna, British Columbia, Canada
| | - C M Tallon
- Centre for Heart, Lung & Vascular Health, University of British Columbia, Kelowna, British Columbia, Canada
| | - D R Perkins
- Cardiff School of Sport & Health Sciences, Cardiff Metropolitan University, Cardiff, UK.,Youth Physical Development Centre, Cardiff School of Sport & Health Sciences, Cardiff Metropolitan University, Cardiff, UK
| | - K J Smith
- Cerebrovascular Health, Exercise, and Environmental Research Sciences, University of Victoria, Victoria, British Columbia, Canada
| | - M Stembridge
- Cardiff School of Sport & Health Sciences, Cardiff Metropolitan University, Cardiff, UK.,Youth Physical Development Centre, Cardiff School of Sport & Health Sciences, Cardiff Metropolitan University, Cardiff, UK
| | - S Piombo
- Pediatric Exercise and Genomics Research Center, University of California Irvine School of Medicine, Irvine, CA, USA
| | - S Radom-Aizik
- Pediatric Exercise and Genomics Research Center, University of California Irvine School of Medicine, Irvine, CA, USA
| | - D M Cooper
- Pediatric Exercise and Genomics Research Center, University of California Irvine School of Medicine, Irvine, CA, USA
| | - P N Ainslie
- Centre for Heart, Lung & Vascular Health, University of British Columbia, Kelowna, British Columbia, Canada
| | - A M McManus
- Centre for Heart, Lung & Vascular Health, University of British Columbia, Kelowna, British Columbia, Canada
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31
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Kelly T, Brown C, Bryant-Ekstrand M, Lord R, Dawkins T, Drane A, Futral JE, Barak O, Dragun T, Stembridge M, Spajić B, Drviš I, Duke JW, Ainslie PN, Foster GE, Dujic Z, Lovering AT. Blunted hypoxic pulmonary vasoconstriction in apnoea divers. Exp Physiol 2022; 107:1225-1240. [PMID: 35993480 DOI: 10.1113/ep090326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Accepted: 08/11/2022] [Indexed: 11/08/2022]
Abstract
NEW FINDINGS What is new and noteworthy? What is the central question of this study? Does the hyperbaric, hypercapnic, acidotic, hypoxic stress of apnoea diving lead to greater pulmonary vasoreactivity and increased right-heart work in apnoea divers? What is the main finding and its importance? Compared to sex- and age-matched controls, Divers had a significantly lower change in total pulmonary resistance in response to short duration isocapnic hypoxia. With oral sildenafil (50 mg), there were no differences in total pulmonary resistance between groups, suggesting Divers can maintain normal pulmonary artery tone in hypoxic conditions. Blunted hypoxic pulmonary vasoconstriction may be beneficial during apnoea diving. ABSTRACT Competitive apnoea divers repetitively dive to depths beyond 50 m. During the final portions of ascent, Divers experience significant hypoxaemia. Additionally, hyperbaria during diving increases thoracic blood volume while simultaneously reducing lung volume, increasing pulmonary artery pressure. We hypothesized that Divers would have exaggerated hypoxic pulmonary vasoconstriction leading to increased right-heart work due to their repetitive hypoxaemia and hyperbaria, and that the administration of sildenafil would have a greater effect in reducing pulmonary resistance in Divers. We recruited 16 Divers and 16 age and sex matched non-diving controls (Controls). Using a double-blinded, placebo-controlled, cross-over design, participants were evaluated for normal cardiac and lung function, then their cardiopulmonary responses to 20-30 minutes of isocapnic hypoxia (end-tidal PO2 = 50 mm Hg) were measured one hour following ingestion of 50 mg sildenafil or placebo. Cardiac structure and cardiopulmonary function were similar at baseline. With placebo, Divers had a significantly smaller increase in total pulmonary resistance than controls after 20-30 minutes isocapnic hypoxia (Δ -3.85 ± 72.85 vs 73.74 ± 91.06 dynes/sec/cm-5 , p = .0222). With sildenafil, Divers and Controls had similarly blunted increases in total pulmonary resistance after 20-30 minutes of hypoxia. Divers also had a significantly lower systemic vascular resistance following sildenafil in normoxia. These data indicate that repetitive apnoea diving leads to a blunted hypoxic pulmonary vasoconstriction. We suggest this is a beneficial adaption allowing for increased cardiac output with reduced right heart work and thus reducing cardiac oxygen utilization under hypoxemic conditions. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Tyler Kelly
- Department of Human Physiology, University of Oregon, Eugene, Oregon, USA
| | - Courtney Brown
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, BC, Canada
| | | | - Rachel Lord
- School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, Wales, UK
| | - Tony Dawkins
- School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, Wales, UK
| | - Aimee Drane
- School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, Wales, UK
| | - Joel E Futral
- Department of Human Physiology, University of Oregon, Eugene, Oregon, USA
| | - Otto Barak
- Department of Physiology, University of Novi Sad, Novi Sad, Serbia
| | - Tanja Dragun
- Department of Integrative Physiology, University of Split School of Medicine, Split, Croatia
| | - Michael Stembridge
- School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, Wales, UK
| | - Boris Spajić
- Faculty of Kinesiology, University of Zagreb, Zagreb, Croatia
| | - Ivan Drviš
- Faculty of Kinesiology, University of Zagreb, Zagreb, Croatia
| | - Joseph W Duke
- Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona, USA
| | - Philip N Ainslie
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, BC, Canada
| | - Glen E Foster
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, BC, Canada
| | - Zeljko Dujic
- Department of Integrative Physiology, University of Split School of Medicine, Split, Croatia
| | - Andrew T Lovering
- Department of Human Physiology, University of Oregon, Eugene, Oregon, USA
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32
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Zhang X, Yamada Y, Sagayama H, Ainslie PN, Blaak EE, Buchowski MS, Close GL, Cooper JA, Das SK, Dugas LR, Gurven M, El Hamdouchi A, Hu S, Joonas N, Katzmarzyk P, Kraus WE, Kushner RF, Leonard WR, Martin CK, Meijer EP, Neuhouser ML, Ojiambo RM, Pitsiladis YP, Plasqui G, Prentice RL, Racette SB, Ravussin E, Redman LM, Reynolds RM, Roberts SB, Sardinha LB, Silva AM, Stice E, Urlacher SS, Van Mil EA, Wood BM, Murphy-Alford AJ, Loechl C, Luke AH, Rood J, Schoeller DA, Westerterp KR, Wong WW, Pontzer H, Speakman JR. Human total, basal and activity energy expenditures are independent of ambient environmental temperature. iScience 2022; 25:104682. [PMID: 35865134 PMCID: PMC9294192 DOI: 10.1016/j.isci.2022.104682] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 05/24/2022] [Accepted: 06/23/2022] [Indexed: 11/02/2022] Open
Abstract
Lower ambient temperature (Ta) requires greater energy expenditure to sustain body temperature. However, effects of Ta on human energetics may be buffered by environmental modification and behavioral compensation. We used the IAEA DLW database for adults in the USA (n = 3213) to determine the effect of Ta (-10 to +30°C) on TEE, basal (BEE) and activity energy expenditure (AEE) and physical activity level (PAL). There were no significant relationships (p > 0.05) between maximum, minimum and average Ta and TEE, BEE, AEE and PAL. After adjustment for fat-free mass, fat mass and age, statistically significant (p < 0.01) relationships between TEE, BEE and Ta emerged in females but the effect sizes were not biologically meaningful. Temperatures inside buildings are regulated at 18-25°C independent of latitude. Hence, adults in the US modify their environments to keep TEE constant across a wide range of external ambient temperatures.
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Affiliation(s)
- Xueying Zhang
- Shenzhen Key Laboratory of Metabolic Health, Center for Energy Metabolism and Reproduction, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China.,Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, UK
| | - Yosuke Yamada
- Institute for Active Health, Kyoto University of Advanced Science, Kyoto, Japan.,National Institute of Health and Nutrition, National Institutes of Biomedical Innovation, Health and Nutrition, Tokyo, Japan
| | - Hiroyuki Sagayama
- Faculty of Health and Sport Sciences, University of Tsukuba, Ibaraki, Japan
| | - Philip N Ainslie
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK.,University of British Columbia, Okanagan Campus School of Health and Exercise Sciences, Faculty of Health and Social Development Kelowna, Kelowna, BC, Canada
| | - Ellen E Blaak
- Department of Human Biology, Maastricht University, Maastricht, the Netherlands
| | - Maciej S Buchowski
- Division of Gastroenterology, Hepatology and Nutrition, Department of Medicine, Vanderbilt University, Nashville, TN, USA
| | - Graeme L Close
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK
| | - Jamie A Cooper
- Nutritional Sciences, University of Georgia, Athens, GA, USA
| | - Sai Krupa Das
- Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, 711 Washington Street, Boston, MA, USA
| | - Lara R Dugas
- Department of Public Health Sciences, Parkinson School of Health Sciences and Public Health, Loyola University, Maywood, IL, USA.,Division of Epidemiology and Biostatistics, School of Public Health and Family Medicine, University of Cape Town, Cape Town, South Africa
| | - Michael Gurven
- Department of Anthropology, University of California Santa Barbara, Santa Barbara, CA, USA
| | - Asmaa El Hamdouchi
- Unité Mixte de Recherche en Nutrition et Alimentation, CNESTEN- Université Ibn Tofail URAC39, Regional Designated Center of Nutrition Associated with AFRA/IAEA, Rabat, Morocco
| | - Sumei Hu
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, Beijing Engineering and Technology Research Center of Food Additives, National Soybean Processing Industry Technology Innovation Center, Beijing Technology and Business University, Beijing, China.,State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Noorjehan Joonas
- Central Health Laboratory, Ministry of Health and Wellness, Port Louis, Mauritius
| | | | | | | | - William R Leonard
- Department of Anthropology, Northwestern University, Evanston, IL, USA
| | - Corby K Martin
- Pennington Biomedical Research Center, Baton Rouge, LA, USA
| | - Erwin P Meijer
- Department of Human Biology, Maastricht University, Maastricht, the Netherlands
| | - Marian L Neuhouser
- Division of Public Health Sciences, Fred Hutchinson Cancer Center and School of Public Health, University of Washington, Seattle, WA, USA
| | - Robert M Ojiambo
- Moi University, Eldoret, Kenya.,University of Global Health Equity, Kigali, Rwanda
| | | | - Guy Plasqui
- Department of Nutrition and Movement Sciences, Maastricht University, Maastricht, the Netherlands
| | - Ross L Prentice
- Division of Public Health Sciences, Fred Hutchinson Cancer Center and School of Public Health, University of Washington, Seattle, WA, USA
| | - Susan B Racette
- Program in Physical Therapy and Department of Medicine, Washington University School of Medicine, St Louis, MO, USA
| | - Eric Ravussin
- Pennington Biomedical Research Center, Baton Rouge, LA, USA
| | | | - Rebecca M Reynolds
- Centre for Cardiovascular Sciences, Queen's Medical Research Institute, University of Edinburgh, Edinburgh, UK
| | - Susan B Roberts
- Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, 711 Washington Street, Boston, MA, USA
| | - Luis B Sardinha
- Exercise and Health Laboratory, CIPER, Department of Sport and Health, Faculdade Motricidade Humana, Universidade de Lisboa, Lisbon, Portugal
| | - Analiza M Silva
- Exercise and Health Laboratory, CIPER, Department of Sport and Health, Faculdade Motricidade Humana, Universidade de Lisboa, Lisbon, Portugal
| | | | - Samuel S Urlacher
- Department of Anthropology, Baylor University, Waco, TX, USA.,Child and Brain Development Program, CIFAR, Toronto, Canada
| | - Edgar A Van Mil
- Maastricht University, Maastricht and Lifestyle Medicine Center for Children, Jeroen Bosch Hospital's-Hertogenbosch, the Netherlands
| | - Brian M Wood
- University of California Los Angeles, Los Angeles, USA.,Max Planck Institute for Evolutionary Anthropology, Department of Human Behavior, Ecology, and Culture. Leipzig, Germany
| | - Alexia J Murphy-Alford
- Nutritional and Health Related Environmental Studies Section, Division of Human Health, International Atomic Energy Agency, Vienna, Austria
| | - Cornelia Loechl
- Nutritional and Health Related Environmental Studies Section, Division of Human Health, International Atomic Energy Agency, Vienna, Austria
| | - Amy H Luke
- Division of Epidemiology, Department of Public Health Sciences, Loyola University School of Medicine, Maywood, IL, USA
| | - Jennifer Rood
- Pennington Biomedical Research Center, Baton Rouge, LA, USA
| | - Dale A Schoeller
- Biotech Center and Nutritional Sciences University of Wisconsin, Madison, WI, USA
| | | | - William W Wong
- Department of Pediatrics, Baylor College of Medicine, USDA/ARS Children's Nutrition Research Center, Houston, TX, USA
| | - Herman Pontzer
- Evolutionary Anthropology, Duke University, Durham, NC, USA.,Duke Global Health Institute, Duke University, Durham, NC, USA
| | - John R Speakman
- Shenzhen Key Laboratory of Metabolic Health, Center for Energy Metabolism and Reproduction, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China.,Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, UK.,State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China.,CAS Center of Excellence in Animal Evolution and Genetics, Kunming, China
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Gibbons TD, Dempsey JA, Thomas KN, Campbell HA, Stothers TAM, Wilson LC, Ainslie PN, Cotter JD. Contribution of the carotid body to thermally mediated hyperventilation in humans. J Physiol 2022; 600:3603-3624. [PMID: 35731687 DOI: 10.1113/jp282918] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2022] [Accepted: 06/15/2022] [Indexed: 01/05/2023] Open
Abstract
Humans hyperventilate under heat and cold strain. This hyperventilatory response has detrimental consequences including acid-base dysregulation, dyspnoea, decreased cerebral blood flow and accelerated brain heating. The ventilatory response to hypoxia is exaggerated under whole-body heating and cooling, indicating that altered carotid body function might contribute to thermally mediated hyperventilation. To address whether the carotid body might contribute to heat- and cold-induced hyperventilation, we indirectly measured carotid body tonic activity via hyperoxia, and carotid body sensitivity via hypoxia, under graded heat and cold strain in 13 healthy participants in a repeated-measures design. We hypothesised that carotid body tonic activity and sensitivity would be elevated in a dose-dependent manner under graded heat and cold strain, thereby supporting its role in driving thermally mediated hyperventilation. Carotid body tonic activity was increased in a dose-dependent manner with heating, reaching 175% above baseline (P < 0.0005), and carotid body suppression with hyperoxia removed all of the heat-induced increase in ventilation (P = 0.9297). Core cooling increased carotid body activity by up to 250% (P < 0.0001), but maximal values were reached with mild cooling and thereafter plateaued. Carotid body sensitivity to hypoxia was profoundly increased by up to 180% with heat stress (P = 0.0097), whereas cooling had no detectable effect on hypoxic sensitivity. In summary, cold stress increased carotid body tonic activity and this effect was saturated with mild cooling, whereas heating had clear dose-dependent effects on carotid body tonic activity and sensitivity. These dose-dependent effects with heat strain indicate that the carotid body probably plays a primary role in driving heat-induced hyperventilation. KEY POINTS: Humans over-breathe (hyperventilate) when under heat and cold stress, and though this has detrimental physiological repercussions, the mechanisms underlying this response are unknown. The carotid body, a small organ that is responsible for driving hyperventilation in hypoxia, was assessed under incremental heat and cold strain. The carotid body drive to breathe, as indirectly assessed by transient hyperoxia, increased in a dose-dependent manner with heating, reaching 175% above baseline; cold stress similarly increased the carotid body drive to breathe, but did not show dose-dependency. Carotid body sensitivity, as indirectly assessed by hypoxic ventilatory responses, was profoundly increased by 70-180% with mild and severe heat strain, whereas cooling had no detectable effect. Carotid body hyperactivity and hypersensitivity are two interrelated mechanisms that probably underlie the increased drive to breathe with heat strain, whereas carotid body hyperactivity during mild cooling may play a subsidiary role in cold-induced hyperventilation.
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Affiliation(s)
- Travis D Gibbons
- School of Physical Education, Sport & Exercise Science, University of Otago, Dunedin, Otago, New Zealand.,Centre for Heart, Lung and Vascular Health, School of Health and Exercise Science, University of British Columbia-Okanagan, Kelowna, British Columbia, Canada
| | - Jerome A Dempsey
- John Rankin Laboratory for Pulmonary Medicine, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, USA
| | - Kate N Thomas
- Department of Surgical Sciences, University of Otago, Dunedin, Otago, New Zealand
| | - Holly A Campbell
- Department of Surgical Sciences, University of Otago, Dunedin, Otago, New Zealand
| | - Tiarna A M Stothers
- School of Physical Education, Sport & Exercise Science, University of Otago, Dunedin, Otago, New Zealand
| | - Luke C Wilson
- Department of Medicine, University of Otago, Dunedin, Otago, New Zealand
| | - Philip N Ainslie
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Science, University of British Columbia-Okanagan, Kelowna, British Columbia, Canada
| | - James D Cotter
- School of Physical Education, Sport & Exercise Science, University of Otago, Dunedin, Otago, New Zealand
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Hansen AB, Moralez G, Amin SB, Hofstätter F, Simpson LL, Gasho C, Tymko MM, Ainslie PN, Lawley JS, Hearon CM. Global REACH 2018: increased adrenergic restraint of blood flow preserves coupling of oxygen delivery and demand during exercise at high-altitude. J Physiol 2022; 600:3483-3495. [PMID: 35738560 PMCID: PMC9357095 DOI: 10.1113/jp282972] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2022] [Accepted: 06/16/2022] [Indexed: 01/05/2023] Open
Abstract
Chronic exposure to hypoxia (high-altitude, HA; >4000 m) attenuates the vasodilatory response to exercise and is associated with a persistent increase in basal sympathetic nerve activity (SNA). The mechanism(s) responsible for the reduced vasodilatation and exercise hyperaemia at HA remains unknown. We hypothesized that heightened adrenergic signalling restrains skeletal muscle blood flow during handgrip exercise in lowlanders acclimatizing to HA. We tested nine adult males (n = 9) at sea-level (SL; 344 m) and following 21-28 days at HA (∼4300 m). Forearm blood flow (FBF; duplex ultrasonography), mean arterial pressure (MAP; brachial artery catheter), forearm vascular conductance (FVC; FBF/MAP), and arterial and venous blood sampling (O2 delivery ( DO2${D}_{{{\rm{O}}}_{\rm{2}}}$ ) and uptake ( V̇O2${\dot{V}}_{{{\rm{O}}}_{\rm{2}}}$ )) were measured at rest and during graded rhythmic handgrip exercise (5%, 15% and 25% of maximum voluntary isometric contraction; MVC) before and after local α- and β-adrenergic blockade (intra-arterial phentolamine and propranolol). HA reduced ΔFBF (25% MVC: SL: 138.3 ± 47.6 vs. HA: 113.4 ± 37.1 ml min-1 ; P = 0.022) and Δ V̇O2${\dot{V}}_{{{\rm{O}}}_{\rm{2}}}$ (25% MVC: SL: 20.3 ± 7.5 vs. HA: 14.3 ± 6.2 ml min-1 ; P = 0.014) during exercise. Local adrenoreceptor blockade at HA restored FBF during exercise (25% MVC: SLα-β blockade : 164.1 ± 71.7 vs. HAα-β blockade : 185.4 ± 66.6 ml min-1 ; P = 0.947) but resulted in an exaggerated relationship between DO2${D}_{{{\rm{O}}}_{\rm{2}}}$ and V̇O2${\dot{V}}_{{{\rm{O}}}_{\rm{2}}}$ ( DO2${D}_{{{\rm{O}}}_{\rm{2}}}$ / V̇O2${\dot{V}}_{{{\rm{O}}}_{\rm{2}}}$ slope: SL: 1.32; HA: slope: 1.86; P = 0.037). These results indicate that tonic adrenergic signalling restrains exercise hyperaemia in lowlanders acclimatizing to HA. The increase in adrenergic restraint is necessary to match oxygen delivery to demand and prevent over perfusion of contracting muscle at HA. KEY POINTS: In exercising skeletal muscle, local vasodilatory signalling and sympathetic vasoconstriction integrate to match oxygen delivery to demand and maintain arterial blood pressure. Exposure to chronic hypoxia (altitude, >4000 m) causes a persistent increase in sympathetic nervous system activity that is associated with impaired functional capacity and diminished vasodilatation during exercise. In healthy male lowlanders exposed to chronic hypoxia (21-28 days; ∼4300 m), local adrenoreceptor blockade (combined α- and β-adrenergic blockade) restored skeletal muscle blood flow during handgrip exercise. However, removal of tonic adrenergic restraint at high altitude caused an excessive rise in blood flow and subsequently oxygen delivery for any given metabolic demand. This investigation is the first to identify greater adrenergic restraint of blood flow during acclimatization to high altitude and provides evidence of a functional role for this adaptive response in regulating oxygen delivery and demand.
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Affiliation(s)
| | - Gilbert Moralez
- Department of Applied Clinical Research, University of Texas Southwestern Medical Center, TX, USA
| | - Sachin B. Amin
- Department of Sport Science, University of Innsbruck, Innsbruck, Austria
| | - Florian Hofstätter
- Department of Sport Science, University of Innsbruck, Innsbruck, Austria
| | - Lydia L. Simpson
- Department of Sport Science, University of Innsbruck, Innsbruck, Austria
| | - Christopher Gasho
- Department of Medicine, Division of Pulmonary and Critical Care, University of Loma Linda, Loma Linda, California, USA
| | - Michael M. Tymko
- Physical Activity and Diabetes Laboratory, Faculty of Kinesiology, Sport and Recreation, University of Alberta, Edmonton, AB, Canada.,Centre of Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia – Okanagan, Kelowna, British Columbia, Canada
| | - Philip N. Ainslie
- Centre of Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia – Okanagan, Kelowna, British Columbia, Canada
| | - Justin S. Lawley
- Department of Sport Science, University of Innsbruck, Innsbruck, Austria
| | - Christopher M. Hearon
- Department of Applied Clinical Research, University of Texas Southwestern Medical Center, TX, USA.,Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Dallas, Dallas, TX, USA.,Correspondence: Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, 7232 Greenville Avenue, Suite 435, Dallas, TX, 75231, USA.
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35
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Janssen Daalen JM, Meinders MJ, Giardina F, Roes KCB, Stunnenberg BC, Mathur S, Ainslie PN, Thijssen DHJ, Bloem BR. Multiple N-of-1 trials to investigate hypoxia therapy in Parkinson's disease: study rationale and protocol. BMC Neurol 2022; 22:262. [PMID: 35836147 PMCID: PMC9281145 DOI: 10.1186/s12883-022-02770-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Accepted: 06/24/2022] [Indexed: 11/30/2022] Open
Abstract
Background Parkinson’s disease (PD) is a neurodegenerative disease, for which no disease-modifying therapies exist. Preclinical and clinical evidence suggest that hypoxia-based therapy might have short- and long-term benefits in PD. We present the contours of the first study to assess the safety, feasibility and physiological and symptomatic impact of hypoxia-based therapy in individuals with PD. Methods/Design In 20 individuals with PD, we will investigate the safety, tolerability and short-term symptomatic efficacy of continuous and intermittent hypoxia using individual, double-blind, randomized placebo-controlled N-of-1 trials. This design allows for dose finding and for including more individualized outcomes, as each individual serves as its own control. A wide range of exploratory outcomes is deployed, including the Movement Disorders Society Unified Parkinson’s Disease Rating scale (MDS-UPDRS) part III, Timed Up & Go Test, Mini Balance Evaluation Systems (MiniBES) test and wrist accelerometry. Also, self-reported impression of overall symptoms, motor and non-motor symptoms and urge to take dopaminergic medication will be assessed on a 10-point Likert scale. As part of a hypothesis-generating part of the study, we also deploy several exploratory outcomes to probe possible underlying mechanisms of action, including cortisol, erythropoietin and platelet-derived growth factor β. Efficacy will be assessed primarily by a Bayesian analysis. Discussion This evaluation of hypoxia therapy could provide insight in novel pathways that may be pursued for PD treatment. This trial also serves as a proof of concept for deploying an N-of-1 design and for including individualized outcomes in PD research, as a basis for personalized treatment approaches. Trial registration ClinicalTrials.gov Identifier: NCT05214287 (registered January 28, 2022).
Supplementary Information The online version contains supplementary material available at 10.1186/s12883-022-02770-7.
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Affiliation(s)
- Jules M Janssen Daalen
- Center of Expertise for Parkinson & Movement Disorders; Nijmegen, the Netherlands, Department of Neurology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Marjan J Meinders
- Center of Expertise for Parkinson & Movement Disorders; Nijmegen, the Netherlands, Department of Neurology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, The Netherlands.,IQ Healthcare, Radboud Institute for Health Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Federica Giardina
- Department of Health Evidence, Radboud Institute for Health Sciences, Radboud University Medical Center, Section Biostatistics, Nijmegen, The Netherlands
| | - Kit C B Roes
- Department of Health Evidence, Radboud Institute for Health Sciences, Radboud University Medical Center, Section Biostatistics, Nijmegen, The Netherlands
| | - Bas C Stunnenberg
- Department of Neurology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, The Netherlands.,Department of Neurology, Rijnstate Hospital, Arnhem, Netherlands
| | | | - Philip N Ainslie
- Center for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, Canada
| | - Dick H J Thijssen
- Department of Physiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Bastiaan R Bloem
- Center of Expertise for Parkinson & Movement Disorders; Nijmegen, the Netherlands, Department of Neurology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, The Netherlands.
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36
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Bailey DM, Bain AR, Hoiland RL, Barak OF, Drvis I, Hirtz C, Lehmann S, Marchi N, Janigro D, MacLeod DB, Ainslie PN, Dujic Z. Hypoxemia increases blood-brain barrier permeability during extreme apnea in humans. J Cereb Blood Flow Metab 2022; 42:1120-1135. [PMID: 35061562 PMCID: PMC9121528 DOI: 10.1177/0271678x221075967] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Voluntary asphyxia imposed by static apnea challenges blood-brain barrier (BBB) integrity in humans through transient extremes of hypertension, hypoxemia and hypercapnia. In the present study, ten ultra-elite breath-hold divers performed two maximal dry apneas preceded by normoxic normoventilation (NX: severe hypoxemia and hypercapnia) and hyperoxic hyperventilation (HX: absence of hypoxemia with exacerbating hypercapnia) with measurements obtained before and immediately after apnea. Transcerebral exchange of NVU proteins (ELISA, Single Molecule Array) were calculated as the product of global cerebral blood flow (gCBF, duplex ultrasound) and radial arterial to internal jugular venous concentration gradients. Apnea duration increased from 5 m 6 s in NX to 15 m 59 s in HX (P = <0.001) resulting in marked elevations in gCBF and venous S100B, glial fibrillary acidic protein, ubiquitin carboxy-terminal hydrolase-L1 and total tau (all P < 0.05 vs. baseline). This culminated in net cerebral output reflecting mildly increased BBB permeability and increased neuronal-gliovascular reactivity that was more pronounced in NX due to more severe systemic and intracranial hypertension (P < 0.05 vs. HX). These findings identify the hemodynamic stress to which the apneic brain is exposed, highlighting the critical contribution of hypoxemia and not just hypercapnia to BBB disruption.
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Affiliation(s)
- Damian M Bailey
- Neurovascular Research Laboratory, Faculty of Life Sciences and Education, 6654University of South Wales, University of South Wales, Glamorgan, UK
| | - Anthony R Bain
- Faculty of Human Kinetics, University of Windsor, Windsor, ON, Canada
| | - Ryan L Hoiland
- Department of Anaesthesiology, Pharmacology and Therapeutics, Vancouver General Hospital, University of British Columbia, Vancouver, BC, Canada.,Department of Cellular and Physiological Sciences, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Otto F Barak
- School of Medicine, University of Split, Split, Croatia.,Faculty of Medicine, University of Novi Sad, Serbia
| | - Ivan Drvis
- School of Kinesiology, University of Zagreb, Zagreb, Croatia
| | - Christophe Hirtz
- LBPC-PPC, University of Montpellier, Institute of Regenerative Medicine-Biotherapy IRMB, Centre Hospitalier Universitaire de Montpellier, INSERM, Montpellier, France
| | - Sylvain Lehmann
- LBPC-PPC, University of Montpellier, Institute of Regenerative Medicine-Biotherapy IRMB, Centre Hospitalier Universitaire de Montpellier, INSERM, Montpellier, France
| | - Nicola Marchi
- Institute of Functional Genomics, University of Montpellier, Montpellier, France
| | - Damir Janigro
- Department of Physiology, Case Western Reserve University, Cleveland, OH, USA.,FloTBI, Cleveland, OH, USA
| | - David B MacLeod
- Department of Anesthesiology, Duke University Medical Center, Durham, NC, USA
| | - Philip N Ainslie
- Neurovascular Research Laboratory, Faculty of Life Sciences and Education, 6654University of South Wales, University of South Wales, Glamorgan, UK.,Center for Heart Lung and Vascular Health, University of British Columbia, Kelowna, British Columbia, Canada
| | - Zeljko Dujic
- School of Medicine, University of Split, Split, Croatia
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37
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Steele AR, Ainslie PN, Stone R, Tymko K, Tymko C, Howe CA, MacLeod D, Anholm JD, Gasho C, Tymko MM. Global REACH 2018: Characterizing Acid-Base Balance Over 21 Days at 4,300 m in Lowlanders. High Alt Med Biol 2022; 23:185-191. [PMID: 35231184 DOI: 10.1089/ham.2021.0115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Steele, Andrew R., Philip N. Ainslie, Rachel Stone, Kaitlyn Tymko, Courtney Tymko, Connor A. Howe, David MacLeod, James D. Anholm, Christopher Gasho, and Michael M. Tymko. Global REACH 2018: characterizing acid-base balance over 21 days at 4,300 m in lowlanders. High Alt Med Biol. 23:185-191, 2022. Introduction: High altitude exposure results in hyperventilatory-induced respiratory alkalosis, followed by metabolic compensation to return arterial blood pH (pHa) toward sea level values. However, previous work has limited sample sizes, short-term exposure, and pharmacological confounders (e.g., acetazolamide). The purpose of this investigation was to characterize acid-base balance after rapid ascent to high altitude (i.e., 4,300 m) in lowlanders. We hypothesized that despite rapid bicarbonate ([HCO3-]) excretion during early acclimatization, partial respiratory alkalosis would still be apparent as reflected in elevations in pHa compared with sea level after 21 days of acclimatization to 4,300 m. Methods: In 16 (3 female) healthy volunteers not taking any medications, radial artery blood samples were collected and analyzed at sea level (150 m; Lima, Peru), and on days 1, 3, 7, 14, and 21 after rapid automobile (∼8 hours) ascent to high altitude (4,300 m; Cerro de Pasco, Peru). Results and Discussion: Although reductions in [HCO3-] occurred by day 3 (p < 0.01), they remained stable thereafter and were insufficient to fully normalize pHa back to sea level values over the subsequent 21 days (p < 0.01). These data indicate that only partial compensation for respiratory alkalosis persists throughout 21 days at 4,300 m.
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Affiliation(s)
- Andrew R Steele
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia-Okanagan, Kelowna, British Columbia, Canada
| | - Philip N Ainslie
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia-Okanagan, Kelowna, British Columbia, Canada
| | - Rachel Stone
- Department of Kinesiology, University of Windsor, Windsor, Ontario, Canada
| | - Kaitlyn Tymko
- Department of Kinesiology and Recreation Management, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Courtney Tymko
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia-Okanagan, Kelowna, British Columbia, Canada
| | - Connor A Howe
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia-Okanagan, Kelowna, British Columbia, Canada
| | - David MacLeod
- Human Pharmacology and Physiology Lab, Duke University Medical Center, Durham, North Carolina, USA
| | - James D Anholm
- Division of Pulmonary and Critical Care, Department of Medicine, School of Medicine, Loma Linda University, Loma Linda, California, USA
| | - Christopher Gasho
- Division of Pulmonary and Critical Care, Department of Medicine, School of Medicine, Loma Linda University, Loma Linda, California, USA
| | - Michael M Tymko
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia-Okanagan, Kelowna, British Columbia, Canada.,Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Edmonton, Alberta, Canada
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38
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DuBose N, Ainslie PN, Sherman SR, Baynard T, Hoiland R, Smith KJ, Green DJ. Exercise and Hypercapnia Differentially Modify Ratios of Extracranial and Intracranial Pulsatility. FASEB J 2022. [DOI: 10.1096/fasebj.2022.36.s1.r5027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Noah DuBose
- Applied Health SciencesUniversity of Illinois at ChicagoOak ParkIL
| | - Philip N. Ainslie
- Centre for Heart, Lung, and Vascular HealthUniversity of British ColumbiaKelownaBC
| | - Sara R. Sherman
- Applied Health SciencesUniversity of Illinois at ChicagoChicagoIL
| | - Tracy Baynard
- Applied Health SciencesUniversity of Illinois at ChicagoChicagoIL
| | - Ryan Hoiland
- Centre for Heart, Lung, and Vascular HealthUniversity of British ColumbiaKelownaBC
| | - Kurt J. Smith
- School of Exercise SciencePhysical and Health EducationUniversity of VictoriaVictoriaBC
| | - Daniel J. Green
- Cardiovascular Research GroupSchool Human Sciences (Sports and Exercise)University of Western AustraliaPerth
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39
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Hansen AB, Amin SB, Hofstätter F, Mugele H, Simpson LL, Gasho C, Dawkins TG, Tymko MM, Ainslie PN, Villafuerte FC, Hearon CM, Lawley JS, Moralez G. Global Reach 2018: sympathetic neural and hemodynamic responses to submaximal exercise in Andeans with and without chronic mountain sickness. Am J Physiol Heart Circ Physiol 2022; 322:H844-H856. [PMID: 35333117 PMCID: PMC9018046 DOI: 10.1152/ajpheart.00555.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Revised: 03/14/2022] [Accepted: 03/14/2022] [Indexed: 11/22/2022]
Abstract
Andeans with chronic mountain sickness (CMS) and polycythemia have similar maximal oxygen uptakes to healthy Andeans. Therefore, this study aimed to explore potential adaptations in convective oxygen transport, with a specific focus on sympathetically mediated vasoconstriction of nonactive skeletal muscle. In Andeans with (CMS+, n = 7) and without (CMS-, n = 9) CMS, we measured components of convective oxygen delivery, hemodynamic (arterial blood pressure via intra-arterial catheter), and autonomic responses [muscle sympathetic nerve activity (MSNA)] at rest and during steady-state submaximal cycling exercise [30% and 60% peak power output (PPO) for 5 min each]. Cycling caused similar increases in heart rate, cardiac output, and oxygen delivery at both workloads between both Andean groups. However, at 60% PPO, CMS+ had a blunted reduction in Δtotal peripheral resistance (CMS-, -10.7 ± 3.8 vs. CMS+, -4.9 ± 4.1 mmHg·L-1·min-1; P = 0.012; d = 1.5) that coincided with a greater Δforearm vasoconstriction (CMS-, -0.2 ± 0.6 vs. CMS+, 1.5 ± 1.3 mmHg·mL-1·min-1; P = 0.008; d = 1.7) and a rise in Δdiastolic blood pressure (CMS-, 14.2 ± 7.2 vs. CMS+, 21.6 ± 4.2 mmHg; P = 0.023; d = 1.2) compared with CMS-. Interestingly, although MSNA burst frequency did not change at 30% or 60% of PPO in either group, at 60% Δburst incidence was attenuated in CMS+ (P = 0.028; d = 1.4). These findings indicate that in Andeans with polycythemia, light intensity exercise elicited similar cardiovascular and autonomic responses compared with CMS-. Furthermore, convective oxygen delivery is maintained during moderate-intensity exercise despite higher peripheral resistance. In addition, the elevated peripheral resistance during exercise was not mediated by greater sympathetic neural outflow, thus other neural and/or nonneural factors are perhaps involved.NEW & NOTEWORTHY During submaximal exercise, convective oxygen transport is maintained in Andeans suffering from polycythemia. Light intensity exercise elicited similar cardiovascular and autonomic responses compared with healthy Andeans. However, during moderate-intensity exercise, we observed a blunted reduction in total peripheral resistance, which cannot be ascribed to an exaggerated increase in muscle sympathetic nerve activity, indicating possible contributions from other neural and/or nonneural mechanisms.
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Affiliation(s)
- Alexander B Hansen
- Division of Performance, Physiology and Prevention, Department of Sport Science, University of Innsbruck, Innsbruck, Austria
| | - Sachin B Amin
- Division of Performance, Physiology and Prevention, Department of Sport Science, University of Innsbruck, Innsbruck, Austria
| | - Florian Hofstätter
- Division of Performance, Physiology and Prevention, Department of Sport Science, University of Innsbruck, Innsbruck, Austria
| | - Hendrik Mugele
- Division of Performance, Physiology and Prevention, Department of Sport Science, University of Innsbruck, Innsbruck, Austria
| | - Lydia L Simpson
- Division of Performance, Physiology and Prevention, Department of Sport Science, University of Innsbruck, Innsbruck, Austria
| | - Christopher Gasho
- Division of Pulmonary and Critical Care, Department of Medicine, University of Loma Linda, Loma Linda, California
| | - Tony G Dawkins
- Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, United Kingdom
| | - Michael M Tymko
- Physical Activity and Diabetes Laboratory, Faculty of Kinesiology and Recreation, University of Alberta, Edmonton, Alberta, Canada
- Centre of Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia Okanagan, Kelowna, British Columbia, Canada
| | - Philip N Ainslie
- Centre of Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia Okanagan, Kelowna, British Columbia, Canada
| | - Francisco C Villafuerte
- Laboratorio de Fisiología Comparada/Fisiología del Transporte de Oxígeno Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Christopher M Hearon
- Department of Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, Texas
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Dallas, Dallas, Texas
| | - Justin S Lawley
- Division of Performance, Physiology and Prevention, Department of Sport Science, University of Innsbruck, Innsbruck, Austria
| | - Gilbert Moralez
- Department of Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, Texas
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40
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White AJ, Boulet LM, Shafer BM, Vermeulen TD, Atwater TL, Stembridge M, Ainslie PN, Wilson RJA, Day TA, Foster GE. The coronary vascular response to the metaboreflex at low-altitude and during acute and prolonged high-altitude in males. J Appl Physiol (1985) 2022; 132:1327-1337. [PMID: 35482323 DOI: 10.1152/japplphysiol.00018.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Myocardial oxygen delivery is primarily regulated through changes in vascular tone to match increased metabolic demands. In males, activation of the muscle metaboreflex during acute isocapnic hypoxia results in a paradoxical coronary vasoconstriction. Whether coronary blood velocity is reduced by metaboreflex activation following travel and/or adaptation to high-altitude is unknown. This study determined if the response of the coronary vasculature to muscle metaboreflex activation at low-altitude differs from acute (1/2 days) and prolonged (8/9 days) high-altitude. Healthy males (n=16) were recruited and performed isometric handgrip exercise (30 % max) followed by post-exercise circulatory occlusion (PECO) to isolate the muscle metaboreflex at low-altitude and following acute and prolonged high-altitude (3,800 m). Mean left anterior descending coronary artery blood velocity (LADvmean, transthoracic Doppler echocardiography), heart rate, mean arterial pressure (MAP), ventilation, and respired gases were assessed during baseline and PECO at all time-points. Coronary vascular conductance index (CVCi) was calculated as LADVmean/MAP. The change in LADvmean (acute altitude: -1.7 ± 3.9 cm/s, low-altitude: 2.6 ± 3.4 cm/s, P = 0.01) and CVCi (acute altitude: -0.05 ± 0.04 cm/s/mmHg, low-altitude: -0.01 ± 0.03 cm/s/mmHg, P = 0.005) induced by PECO differed significantly between acute high-altitude and low-altitude. The change in LADVmean and CVCi induced by PECO following prolonged high-altitude was not different from low-altitude. Our results suggest that coronary vasoconstriction with metaboreflex activation in males is greatest following acute ascent to high-altitude and restored to low-altitude levels following 8-9 days of acclimatization.
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Affiliation(s)
- Austin J White
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, British Columbia, Kelowna, Canada
| | - Lindsey M Boulet
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, British Columbia, Kelowna, Canada
| | - Brooke M Shafer
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, British Columbia, Kelowna, Canada
| | - Tyler D Vermeulen
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, British Columbia, Kelowna, Canada
| | - Taylor L Atwater
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, British Columbia, Kelowna, Canada
| | - Mike Stembridge
- Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, United Kingdom
| | - Philip N Ainslie
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, British Columbia, Kelowna, Canada
| | - Richard J A Wilson
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Canada
| | - Trevor A Day
- Department of Biology, Faculty of Science and Technology, Mount Royal University, Calgary, Alberta, Canada
| | - Glen Edward Foster
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, British Columbia, Kelowna, Canada
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41
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Caldwell HG, Hoiland RL, Smith KJ, Brassard P, Bain AR, Tymko MM, Howe CA, Carr JM, Stacey BS, Bailey DM, Drapeau A, Sekhon MS, MacLeod DB, Ainslie PN. Trans-cerebral HCO 3- and PCO 2 exchange during acute respiratory acidosis and exercise-induced metabolic acidosis in humans. J Cereb Blood Flow Metab 2022; 42:559-571. [PMID: 34904461 PMCID: PMC8943603 DOI: 10.1177/0271678x211065924] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
This study investigated trans-cerebral internal jugular venous-arterial bicarbonate ([HCO3-]) and carbon dioxide tension (PCO2) exchange utilizing two separate interventions to induce acidosis: 1) acute respiratory acidosis via elevations in arterial PCO2 (PaCO2) (n = 39); and 2) metabolic acidosis via incremental cycling exercise to exhaustion (n = 24). During respiratory acidosis, arterial [HCO3-] increased by 0.15 ± 0.05 mmol ⋅ l-1 per mmHg elevation in PaCO2 across a wide physiological range (35 to 60 mmHg PaCO2; P < 0.001). The narrowing of the venous-arterial [HCO3-] and PCO2 differences with respiratory acidosis were both related to the hypercapnia-induced elevations in cerebral blood flow (CBF) (both P < 0.001; subset n = 27); thus, trans-cerebral [HCO3-] exchange (CBF × venous-arterial [HCO3-] difference) was reduced indicating a shift from net release toward net uptake of [HCO3-] (P = 0.004). Arterial [HCO3-] was reduced by -0.48 ± 0.15 mmol ⋅ l-1 per nmol ⋅ l-1 increase in arterial [H+] with exercise-induced acidosis (P < 0.001). There was no relationship between the venous-arterial [HCO3-] difference and arterial [H+] with exercise-induced acidosis or CBF; therefore, trans-cerebral [HCO3-] exchange was unaltered throughout exercise when indexed against arterial [H+] or pH (P = 0.933 and P = 0.896, respectively). These results indicate that increases and decreases in systemic [HCO3-] - during acute respiratory/exercise-induced metabolic acidosis, respectively - differentially affect cerebrovascular acid-base balance (via trans-cerebral [HCO3-] exchange).
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Affiliation(s)
- Hannah G Caldwell
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia Okanagan, Kelowna, BC, Canada
| | - Ryan L Hoiland
- Department of Anesthesiology, Pharmacology and Therapeutics, Vancouver General Hospital, University of British Columbia, Vancouver, BC, Canada.,Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Kurt J Smith
- Department of Exercise Science, Physical and Health Education, Faculty of Education, University of Victoria, Victoria, British Columbia, Canada
| | - Patrice Brassard
- Department of Kinesiology, Faculty of Medicine, Université Laval, Québec, Canada.,Research Center of the Institut Universitaire de Cardiologie et de Pneumologie de Québec, QC, Canada
| | - Anthony R Bain
- Faculty of Human Kinetics, Department of Kinesiology, University of Windsor, Windsor, ON, Canada
| | - Michael M Tymko
- Neurovascular Health Laboratory, Faculty of Kinesiology, Sport and Recreation, University of Alberta, Edmonton, AB, Canada
| | - Connor A Howe
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia Okanagan, Kelowna, BC, Canada
| | - Jay Mjr Carr
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia Okanagan, Kelowna, BC, Canada
| | - Benjamin S Stacey
- Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, Pontypridd, UK
| | - Damian M Bailey
- Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, Pontypridd, UK
| | - Audrey Drapeau
- Department of Kinesiology, Faculty of Medicine, Université Laval, Québec, Canada.,Research Center of the Institut Universitaire de Cardiologie et de Pneumologie de Québec, QC, Canada
| | - Mypinder S Sekhon
- Division of Critical Care Medicine, Department of Medicine, 8167Vancouver General Hospital, Vancouver General Hospital, University of British Columbia, Vancouver, BC, Canada
| | - David B MacLeod
- Human Pharmacology and Physiology Lab, Department of Anesthesiology, Duke University Medical Center, Durham, NC, USA
| | - Philip N Ainslie
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia Okanagan, Kelowna, BC, Canada
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42
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Stembridge DM, Ainslie PN, West JB. Elevating Physiology; Griffith Pugh on the limits of human performance and survival. J Physiol 2022; 600:1811-1813. [DOI: 10.1113/jp282834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Dr Mike Stembridge
- Cardiff School of Sport and Health Sciences Cardiff Metropolitan University
| | - Philip N. Ainslie
- Centre for Lung, Heart and Vascular Health University of British Columbia Okanagan
| | - John B. West
- Department of Medicine University of California San Diego
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43
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Tymko MM, Willie CK, Howe CA, Hoiland RL, Stone R, Tymko K, Tymko C, MacLeod DB, Anholm J, Gasho C, Villafuerte FC, Vizcardo Galindo GA, Figueroa-Mujíca RJ, Day TA, Bird JD, Foster GE, Steinback CD, Brugniaux J, Champigneulle B, Stauffer E, Doutreleau S, Verges S, Swenson ER, Ainslie PN. Acid-base balance at high altitude in lowlanders and indigenous highlanders. J Appl Physiol (1985) 2022; 132:575-580. [PMID: 35023761 DOI: 10.1152/japplphysiol.00757.2021] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
High-altitude exposure results in a hyperventilatory-induced respiratory alkalosis followed by renal compensation (bicarbonaturia) to return arterial blood pH(a) toward sea-level values. However, acid-base balance has not been comprehensively examined in both lowlanders and indigenous populations - where the latter are thought to be fully adapted to high-altitude. The purpose of this investigation was to compare acid-base balance between acclimatizing lowlanders, and Andean and Sherpa highlanders at various altitudes (~3,800, ~4,300, and ~5,000 m). We compiled data collected across five independent high-altitude expeditions and report the following novel findings: 1) at 3,800 m, Andeans (n=7) had elevated pHa compared to Sherpas (n=12; P<0.01), but not to lowlanders (n=16; nine days acclimatized; P=0.09); 2) at 4,300 m, lowlanders (n=16; 21 days acclimatized) had elevated pHa compared to Andeans (n=32) and Sherpas (n=11; both P<0.01), and Andeans had elevated pHa compared to Sherpas (P=0.01); and 3) at 5,000 m, lowlanders (n=16; 14 days acclimatized) had higher pHa compared to both Andeans (n=66) and Sherpas (n=18; P<0.01, and P=0.03, respectively), and Andean and Sherpa highlanders had similar blood pHa (P=0.65). These novel data characterize acid-base balance acclimatization and adaptation to various altitudes in lowlanders and indigenous highlanders.
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Affiliation(s)
- Michael M Tymko
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan, Kelowna, Canada.,Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Edmonton, Canada
| | - Christopher K Willie
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan, Kelowna, Canada
| | - Connor A Howe
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan, Kelowna, Canada
| | - Ryan L Hoiland
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan, Kelowna, Canada.,Department of Anaesthesiology, Pharmacology and Therapeutics, Faculty of Medicine, Vancouver General Hospital, University of British Columbia, Vancouver, BC, Canada.,Department of Cellular and Physiological Sciences, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada.,International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, British Columbia, Canada
| | | | | | - Courtney Tymko
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan, Kelowna, Canada
| | - David B MacLeod
- Human Pharmacology and Physiology Lab, Duke University Medical Center, Durham, NC, United States
| | - James Anholm
- Department of Medicine, Division of Pulmonary and Critical Care, Loma Linda University School of Medicine, Loma, CA, United States
| | - Christopher Gasho
- Department of Medicine, Division of Pulmonary and Critical Care, Loma Linda University School of Medicine, Loma, CA, United States
| | | | - Gustavo A Vizcardo Galindo
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan, Kelowna, Canada.,Universidad Peruana Cayetano Heredia, Lima, Peru
| | | | - Trevor A Day
- Department of Biology, Faculty of Science and Technology, Mount Royal University, Calgary, Alberta, Canada
| | - Jordan D Bird
- Department of Biology, Faculty of Science and Technology, Mount Royal University, Calgary, Alberta, Canada
| | - Glen Edward Foster
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan, Kelowna, Canada
| | - Craig D Steinback
- Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Edmonton, Canada
| | - Julien Brugniaux
- HP2 laboratory, Univ. Grenoble Alpes, INSERM, CHU Grenoble Alpes, Grenoble, France
| | - Benoit Champigneulle
- HP2 laboratory, Univ. Grenoble Alpes, INSERM, CHU Grenoble Alpes, Grenoble, France
| | - Emeric Stauffer
- Laboratoire Interuniversitaire de Biologie de la Motricité (LIBM) EA7424,Université Claude Bernard Lyon 1, France
| | - Stephane Doutreleau
- HP2 laboratory, Univ. Grenoble Alpes, INSERM, CHU Grenoble Alpes, Grenoble, France
| | - Samuel Verges
- HP2 laboratory, Univ. Grenoble Alpes, INSERM, CHU Grenoble Alpes, Grenoble, France
| | - Erik R Swenson
- UPulmonary and Critical Care Medicine, VA Puget Sound Health Care System, University of Washington, Seattle, WA
| | - Philip N Ainslie
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan, Kelowna, Canada
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44
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Hoiland RL, Caldwell HG, Carr JMJR, Howe CA, Stacey BS, Dawkins T, Wakeham DJ, Tremblay JC, Tymko MM, Patrician A, Smith KJ, Sekhon MS, MacLeod DB, Green DJ, Bailey DM, Ainslie PN. Nitric oxide contributes to cerebrovascular shear-mediated dilatation but not steady-state cerebrovascular reactivity to carbon dioxide. J Physiol 2021; 600:1385-1403. [PMID: 34904229 DOI: 10.1113/jp282427] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 12/07/2021] [Indexed: 12/15/2022] Open
Abstract
Cerebrovascular CO2 reactivity (CVR) is often considered a bioassay of cerebrovascular endothelial function. We recently introduced a test of cerebral shear-mediated dilatation (cSMD) that may better reflect endothelial function. We aimed to determine the nitric oxide (NO)-dependency of CVR and cSMD. Eleven volunteers underwent a steady-state CVR test and transient CO2 test of cSMD during intravenous infusion of the NO synthase inhibitor NG -monomethyl-l-arginine (l-NMMA) or volume-matched saline (placebo; single-blinded and counter-balanced). We measured cerebral blood flow (CBF; duplex ultrasound), intra-arterial blood pressure and P aC O 2 . Paired arterial and jugular venous blood sampling allowed for the determination of trans-cerebral NO2 - exchange (ozone-based chemiluminescence). l-NMMA reduced arterial NO2 - by ∼25% versus saline (74.3 ± 39.9 vs. 98.1 ± 34.2 nM; P = 0.03). The steady-state CVR (20.1 ± 11.6 nM/min at baseline vs. 3.2 ± 16.7 nM/min at +9 mmHg P aC O 2 ; P = 0.017) and transient cSMD tests (3.4 ± 5.9 nM/min at baseline vs. -1.8 ± 8.2 nM/min at 120 s post-CO2 ; P = 0.044) shifted trans-cerebral NO2 - exchange towards a greater net release (a negative value indicates release). Although this trans-cerebral NO2 - release was abolished by l-NMMA, CVR did not differ between the saline and l-NMMA trials (57.2 ± 14.6 vs. 54.1 ± 12.1 ml/min/mmHg; P = 0.49), nor did l-NMMA impact peak internal carotid artery dilatation during the steady-state CVR test (6.2 ± 4.5 vs. 6.2 ± 5.0% dilatation; P = 0.960). However, l-NMMA reduced cSMD by ∼37% compared to saline (2.91 ± 1.38 vs. 4.65 ± 2.50%; P = 0.009). Our findings indicate that NO is not an obligatory regulator of steady-state CVR. Further, our novel transient CO2 test of cSMD is largely NO-dependent and provides an in vivo bioassay of NO-mediated cerebrovascular function in humans. KEY POINTS: Emerging evidence indicates that a transient CO2 stimulus elicits shear-mediated dilatation of the internal carotid artery, termed cerebral shear-mediated dilatation. Whether or not cerebrovascular reactivity to a steady-state CO2 stimulus is NO-dependent remains unclear in humans. During both a steady-state cerebrovascular reactivity test and a transient CO2 test of cerebral shear-mediated dilatation, trans-cerebral nitrite exchange shifted towards a net release indicating cerebrovascular NO production; this response was not evident following intravenous infusion of the non-selective NO synthase inhibitor NG -monomethyl-l-arginine. NO synthase blockade did not alter cerebrovascular reactivity in the steady-state CO2 test; however, cerebral shear-mediated dilatation following a transient CO2 stimulus was reduced by ∼37% following intravenous infusion of NG -monomethyl-l-arginine. NO is not obligatory for cerebrovascular reactivity to CO2 , but is a key contributor to cerebral shear-mediated dilatation.
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Affiliation(s)
- Ryan L Hoiland
- Department of Anesthesiology, Pharmacology and Therapeutics, Faculty of Medicine, Vancouver General Hospital, University of British Columbia, Vancouver, British Columbia, Canada.,Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia Okanagan, Kelowna, British Columbia, Canada.,Department of Cellular and Physiological Sciences, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada.,International Collaboration on Repair Discoveries (ICORD), University of British Columbia, Vancouver, British Columbia, Canada
| | - Hannah G Caldwell
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia Okanagan, Kelowna, British Columbia, Canada
| | - Jay M J R Carr
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia Okanagan, Kelowna, British Columbia, Canada
| | - Connor A Howe
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia Okanagan, Kelowna, British Columbia, Canada
| | - Benjamin S Stacey
- Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, Pontypridd, UK
| | - Tony Dawkins
- Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, UK
| | - Denis J Wakeham
- Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, UK
| | - Joshua C Tremblay
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia Okanagan, Kelowna, British Columbia, Canada
| | - Michael M Tymko
- Neurovascular Health Laboratory, University of Alberta, Edmonton, Alberta, Canada
| | - Alexander Patrician
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia Okanagan, Kelowna, British Columbia, Canada
| | - Kurt J Smith
- Integrative Physiology Laboratory, Department of Kinesiology and Nutrition, College of Applied Health Sciences, University of Illinois, Chicago, IL, USA.,Cerebrovascular Health, Exercise, and Environmental Research Science (CHEERS) Laboratory, School of Exercise Science, Physical and Health Education, Faculty of Education, University of Victoria, Victoria, British Columbia, Canada
| | - Mypinder S Sekhon
- Division of Critical Care Medicine, Department of Medicine, Faculty of Medicine, Vancouver General Hospital, University of British Columbia, Vancouver, British Columbia, Canada
| | - David B MacLeod
- Human Pharmacology and Physiology Lab, Department of Anesthesiology, Duke University Medical Center, Durham, NC, USA
| | - Daniel J Green
- School of Human Sciences (Exercise and Sport Sciences), University of Western Australia, Nedlands, Western Australia, Australia
| | - Damian M Bailey
- Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, Pontypridd, UK
| | - Philip N Ainslie
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia Okanagan, Kelowna, British Columbia, Canada
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45
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Burma JS, Kennedy CM, Penner LC, Miutz LN, Galea OA, Ainslie PN, Smirl JD. Long-term heart transplant recipients: heart rate-related effects on augmented transfer function coherence during repeated squat-stand maneuvers in males. Am J Physiol Regul Integr Comp Physiol 2021; 321:R925-R937. [PMID: 34730005 DOI: 10.1152/ajpregu.00177.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Previous research has highlighted that squat-stand maneuvers (SSMs) augment coherence values within the cerebral pressure-flow relationship to ∼0.99. However, it is not fully elucidated if mean arterial pressure (MAP) leads to this physiological entrainment independently, or if heart rate (HR) and/or the partial pressure of carbon dioxide (Pco2) also have contributing influences. A 2:1 control-to-case model was used in the present investigation [participant number (n) = 40; n = 16 age-matched (AM); n = 16 donor control (DM); n = 8 heart transplant recipients (HTRs)]. The latter group was used to mechanistically isolate the extent to which HR influences the cerebral pressure-flow relationship. Participants completed 5 min of squat-stand maneuvers at 0.05 Hz (10 s) and 0.10 Hz (5 s). Linear transfer function analysis (TFA) examined the relationship between different physiological inputs (i.e., MAP, HR, and Pco2) and output [cerebral blood velocity (CBV)] during SSM; and cardiac baroreceptor sensitivity (BRS). Compared with DM, cardiac BRS was reduced in AM (P < 0.001), which was further reduced in HTR (P < 0.045). In addition, during the SSM, HR was elevated in HTR compared with both control groups (P < 0.001), but all groups had near-maximal coherence metrics ≥0.98 at 0.05 Hz and ≥0.99 at 0.10 Hz (P ≥ 0.399). In contrast, the mean HR-CBV/Pco2-CBV relationships ranged from 0.38 (HTR) to 0.81 (DM). Despite near abolishment of BRS and blunted HR following heart transplantation, long-term HTR exhibited near-maximal coherence within the MAP-CBV relationship, comparable with AM and DM. Therefore, these results show that the augmented coherence with SSM is driven by blood pressure, whereas elevations in TFA coherence as a result of HR contribution are likely correlational in nature.
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Affiliation(s)
- Joel S Burma
- Cerebrovascular Concussion Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada.,Sport Injury Prevention Research Centre, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada.,Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada.,Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada.,Integrated Concussion Research Program, University of Calgary, Calgary, Alberta, Canada.,Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta, Canada.,Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada
| | - Courtney M Kennedy
- Cerebrovascular Concussion Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada.,Sport Injury Prevention Research Centre, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada.,Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada.,Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada.,Integrated Concussion Research Program, University of Calgary, Calgary, Alberta, Canada.,Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta, Canada.,Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada
| | - Linden C Penner
- Cerebrovascular Concussion Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada.,Sport Injury Prevention Research Centre, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada.,Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada.,Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada.,Integrated Concussion Research Program, University of Calgary, Calgary, Alberta, Canada.,Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta, Canada.,Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada
| | - Lauren N Miutz
- Cerebrovascular Concussion Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada.,Sport Injury Prevention Research Centre, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada.,Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada.,Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada.,Integrated Concussion Research Program, University of Calgary, Calgary, Alberta, Canada.,Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta, Canada.,Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada
| | - Olivia A Galea
- Cerebrovascular Concussion Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada.,Sport Injury Prevention Research Centre, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada.,Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada.,Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada.,Integrated Concussion Research Program, University of Calgary, Calgary, Alberta, Canada.,Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta, Canada.,Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada
| | - Philip N Ainslie
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, Faculty of Health and Social Development, University of British Columbia, Kelowna, British Columbia, Canada
| | - Jonathan D Smirl
- Cerebrovascular Concussion Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada.,Sport Injury Prevention Research Centre, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada.,Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada.,Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada.,Integrated Concussion Research Program, University of Calgary, Calgary, Alberta, Canada.,Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta, Canada.,Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada.,Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, Faculty of Health and Social Development, University of British Columbia, Kelowna, British Columbia, Canada
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46
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Koep JL, Taylor CE, Coombes JS, Bond B, Ainslie PN, Bailey TG. Autonomic control of cerebral blood flow: fundamental comparisons between peripheral and cerebrovascular circulations in humans. J Physiol 2021; 600:15-39. [PMID: 34842285 DOI: 10.1113/jp281058] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 11/25/2021] [Indexed: 01/12/2023] Open
Abstract
Understanding the contribution of the autonomic nervous system to cerebral blood flow (CBF) control is challenging, and interpretations are unclear. The identification of calcium channels and adrenoreceptors within cerebral vessels has led to common misconceptions that the function of these receptors and actions mirror those of the peripheral vasculature. This review outlines the fundamental differences and complex actions of cerebral autonomic activation compared with the peripheral circulation. Anatomical differences, including the closed nature of the cerebrovasculature, and differential adrenoreceptor subtypes, density, distribution and sensitivity, provide evidence that measures on peripheral sympathetic nerve activity cannot be extrapolated to the cerebrovasculature. Cerebral sympathetic nerve activity seems to act opposingly to the peripheral circulation, mediated at least in part by changes in intracranial pressure and cerebral blood volume. Additionally, heterogeneity in cerebral adrenoreceptor distribution highlights region-specific autonomic regulation of CBF. Compensatory chemo- and autoregulatory responses throughout the cerebral circulation, and interactions with parasympathetic nerve activity are unique features to the cerebral circulation. This crosstalk between sympathetic and parasympathetic reflexes acts to ensure adequate perfusion of CBF to rising and falling perfusion pressures, optimizing delivery of oxygen and nutrients to the brain, while attempting to maintain blood volume and intracranial pressure. Herein, we highlight the distinct similarities and differences between autonomic control of cerebral and peripheral blood flow, and the regional specificity of sympathetic and parasympathetic regulation within the cerebrovasculature. Future research directions are outlined with the goal to further our understanding of autonomic control of CBF in humans.
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Affiliation(s)
- Jodie L Koep
- Physiology and Ultrasound Laboratory in Science and Exercise, Centre for Research on Exercise, Physical Activity and Health, School of Human Movement and Nutrition Sciences, The University of Queensland, Brisbane, Queensland, Australia.,Children's Health and Exercise Research Centre, Sport and Health Sciences, College of Life and Environmental Sciences, University of Exeter, Exeter, UK
| | - Chloe E Taylor
- School of Health Sciences, Western Sydney University, Sydney, Australia
| | - Jeff S Coombes
- Physiology and Ultrasound Laboratory in Science and Exercise, Centre for Research on Exercise, Physical Activity and Health, School of Human Movement and Nutrition Sciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Bert Bond
- Children's Health and Exercise Research Centre, Sport and Health Sciences, College of Life and Environmental Sciences, University of Exeter, Exeter, UK
| | - Philip N Ainslie
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan, Kelowna, British Columbia, Canada
| | - Tom G Bailey
- Physiology and Ultrasound Laboratory in Science and Exercise, Centre for Research on Exercise, Physical Activity and Health, School of Human Movement and Nutrition Sciences, The University of Queensland, Brisbane, Queensland, Australia.,School of Nursing, Midwifery and Social Work, The University of Queensland, Brisbane, Queensland, Australia
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47
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Stone RM, Ainslie PN, Tremblay JC, Akins JD, MacLeod DB, Tymko MM, DeSouza CA, Bain AR. GLOBAL REACH 2018: intra-arterial vitamin C improves endothelial-dependent vasodilatory function in humans at high altitude. J Physiol 2021; 600:1373-1383. [PMID: 34743333 DOI: 10.1113/jp282281] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Accepted: 10/11/2021] [Indexed: 12/20/2022] Open
Abstract
High altitude-induced hypoxaemia is often associated with peripheral vascular dysfunction. However, the basic mechanism(s) underlying high-altitude vascular impairments remains unclear. This study tested the hypothesis that oxidative stress contributes to the impairments in endothelial function during early acclimatization to high altitude. Ten young healthy lowlanders were tested at sea level (344 m) and following 4-6 days at high altitude (4300 m). Vascular endothelial function was determined using the isolated perfused forearm technique with forearm blood flow (FBF) measured by strain-gauge venous occlusion plethysmography. FBF was quantified in response to acetylcholine (ACh), sodium nitroprusside (SNP) and a co-infusion of ACh with the antioxidant vitamin C (ACh+VitC). The total FBF response to ACh (area under the curve) was ∼30% lower at high altitude than at sea level (P = 0.048). There was no difference in the response to SNP at high altitude (P = 0.860). At sea level, the co-infusion of ACh+VitC had no influence on the FBF dose response (P = 0.268); however, at high altitude ACh+VitC resulted in an average increase in the FBF dose response by ∼20% (P = 0.019). At high altitude, the decreased FBF response to ACh, and the increase in FBF in response to ACh+VitC, were associated with the magnitude of arterial hypoxaemia (R2 = 0.60, P = 0.008 and R2 = 0.63, P = 0.006, respectively). Collectively, these data support the hypothesis that impairments in vascular endothelial function at high altitude are in part attributable to oxidative stress, a consequence of the magnitude of hypoxaemia. These data extend our basic understanding of vascular (mal)adaptation to high-altitude sojourns, with important implications for understanding the aetiology of high altitude-related vascular dysfunction. KEY POINTS: Vascular dysfunction has been demonstrated in lowlanders at high altitude (>4000 m). However, the extent of impairment and the delineation of contributing mechanisms have remained unclear. Using the gold-standard isolated perfused forearm model, we determined the extent of vasodilatory dysfunction and oxidative stress as a contributing mechanism in healthy lowlanders before and 4-6 days after rapid ascent to 4300 m. The total forearm blood flow response to acetylcholine at high altitude was decreased by ∼30%. Co-infusion of acetylcholine with the antioxidant vitamin C partially restored the total forearm blood flow by ∼20%. The magnitude of forearm blood flow reduction, as well as the impact of oxidative stress, was positively associated with the individual severity of hypoxaemia. These data extend our basic understanding of vascular (mal)adaptation to high-altitude sojourns, with important implications for understanding the aetiology of high altitude-related changes in endothelial-mediated vasodilatory function.
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Affiliation(s)
- Rachel M Stone
- Faculty of Human Kinetics, University of Windsor, Ontario, Canada
| | - Philip N Ainslie
- Kelowna, Centre for Heart Lung and Vascular Health, University of British Columbia, Vancouver, Canada
| | - Joshua C Tremblay
- Kelowna, Centre for Heart Lung and Vascular Health, University of British Columbia, Vancouver, Canada
| | | | - David B MacLeod
- Duke University School of Medicine, Durham, North Carolina, USA
| | | | | | - Anthony R Bain
- Faculty of Human Kinetics, University of Windsor, Ontario, Canada
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48
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Soriano JE, Romac R, Squair JW, Barak OF, Sarafis ZK, Lee AH, Coombs GB, Vaseghi B, Grant C, Charbonneau R, Mijacika T, Krassioukov A, Ainslie PN, Larkin-Kaiser KA, Phillips A, Dujic Z. Passive leg cycling increases activity of the cardiorespiratory system in people with tetraplegia. Appl Physiol Nutr Metab 2021; 47:269-277. [PMID: 34739759 DOI: 10.1139/apnm-2021-0523] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Individuals with cervical spinal cord injury (SCI) are at an increased risk for cardiovascular disease. Exercise is well-established for preventing cardiovascular disease, however, there are limited straightforward and safe exercise approaches for increasing the activity of the cardiorespiratory system after cervical SCI. The objective of this study was to investigate the cardiorespiratory response to passive leg cycling in people with cervical SCI. Beat-by-beat blood pressure, heart rate, and cerebral blood flow were measured before and throughout 10 minutes of cycling in 11 people with SCI. Femoral artery flow-mediated dilation was also assessed before and immediately after passive cycling. Safety was monitored throughout all study visits. Passive cycling elevated systolic blood pressure (5±2 mmHg), mean arterial pressure (5±3 mmHg), stroke volume (2.4±0.8 mL), heart rate (2±1 beats/min) and cardiac output (0.3±0.07 L/min; all p<0.05). Minute ventilation (0.67±0.23 L/min), tidal volume (70±30 mL) and end-tidal PO2 (2.6±1.23 mmHg) also increased (all p<0.05). Endothelial function was improved immediately after exercise (1.62±0.13%, p<0.01). Passive cycling resulted in one incidence of autonomic dysreflexia. Therefore, passive leg cycling increased the activity of the cardiorespiratory system, improved endothelial function, indicating it may be a beneficial exercise intervention for the cardiovascular and respiratory systems in people with cervical SCI. Novelty: ● Passive leg cycling increases the activity of the cardiorespiratory system and improves markers of cardiovascular health in cervical SCI. ● Passive leg cycling exercise is an effective, low-cost, practical, alternative exercise modality for people with cervical SCI.
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Affiliation(s)
- Jan Elaine Soriano
- University of Calgary, 2129, Departments of Physiology and Pharmacology, Cardiac Sciences & Clinical Neurosciences, Calgary, Alberta, Canada;
| | - Rinaldo Romac
- Clinical Hospital Center Split, Department of Neurology, Split, Croatia;
| | - Jordan W Squair
- University of Calgary, 2129, Departments of Physiology and Pharmacology, Cardiac Sciences & Clinical Neurosciences, Calgary, Alberta, Canada.,University of British Columbia, Faculty of Medicine, Vancouver, British Columbia, Canada;
| | - Otto F Barak
- University of Novi Sad, 84981, Faculty of Medicine, Novi Sad, Serbia;
| | - Zoe K Sarafis
- University of British Columbia, Faculty of Medicine , Vancouver, Canada.,ETH Zurich, 27219, Department of Health Sciences and Technology, Zurich, Switzerland;
| | - Amanda Hx Lee
- University of British Columbia, Faculty of Medicine , Vancouver, British Columbia, Canada.,University of British Columbia, Department of Experimental Medicine, Vancouver, British Columbia, Canada;
| | - Geoff B Coombs
- The University of British Columbia Okanagan, 97950, Centre for Heart, Lung, and Vascular Health, Kelowna, British Columbia, Canada;
| | - Bita Vaseghi
- University of Calgary, 2129, Departments of Physiology and Pharmacology, Cardiac Sciences & Clinical Neurosciences, Calgary, Alberta, Canada.,University of British Columbia, Faculty of Medicine, Vancouver, British Columbia, Canada;
| | - Christopher Grant
- University of Calgary, 2129, Department of Clinical Neurosciences, Calgary, Alberta, Canada;
| | - Rebecca Charbonneau
- University of Calgary, 2129, Department of Clinical Neurosciences, Calgary, Alberta, Canada;
| | - Tanja Mijacika
- University of Split, 74422, Department of Integrative Physiology, Split, Croatia;
| | - Andrei Krassioukov
- University of British Columbia, Faculty of Medicine, Vancouver, British Columbia, Canada.,The University of British Columbia, 8166, Division of Physical Medicine & Rehabilitation, Vancouver, British Columbia, Canada.,G F Strong Rehabilitation Hospital, 103221, Vancouver, British Columbia, Canada;
| | - Philip N Ainslie
- University of British Columbia, Centre for Heart, Lung and Vascular Health, Kelowna, British Columbia, Canada;
| | - Kelly A Larkin-Kaiser
- University of Calgary, Departments of Physiology and Pharmacology, Cardiac Sciences, & Clinical Neurosciences, Calgary, Alberta, Canada;
| | - Aaron Phillips
- University of Calgary, 2129, Departments of Physiology and Pharmacology, Cardiac Sciences & Clinical Neurosciences, Calgary, Canada, T2N 1N4;
| | - Zeljko Dujic
- University of Split School of Medicine, Department of Integrative Physiology, Split, Splitsko-dalmatinska, Croatia;
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49
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Carr JMJR, Caldwell HG, Carter H, Smith K, Tymko MM, Green DJ, Ainslie PN, Hoiland RL. The stability of cerebrovascular CO 2 reactivity following attainment of physiological steady-state. Exp Physiol 2021; 106:2542-2555. [PMID: 34730862 DOI: 10.1113/ep089982] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Accepted: 10/14/2021] [Indexed: 11/08/2022]
Abstract
NEW FINDINGS What is the central question of this study? During a steady-state cerebrovascular CO2 reactivity test, do different data extraction time points change the outcome for cerebrovascular CO2 reactivity? What is the main finding and its importance? Once steady-state end-tidal pressure of CO2 and haemodynamics were achieved, cerebral blood flow was stable, and so cerebrovascular CO2 reactivity values remained unchanged regardless of data extraction length (30 vs. 60 s) and time point (at 2-5 min). ABSTRACT This study assessed cerebrovascular CO2 reactivity (CVR) and examined data extraction time points and durations with the hypotheses that: (1) there would be no difference in CVR values when calculated with cerebral blood flow (CBF) measures at different time points following the attainment of physiological steady-state, (2) once steady-state was achieved there would be no difference in CVR values derived from 60 to 30 s extracted means, and (3) that changes in V ̇ E would not be associated with any changes in CVR. We conducted a single step iso-oxic hypercapnic CVR test using dynamic end-tidal forcing (end-tidal P C O 2 , +9.4 ± 0.7 mmHg), and transcranial Doppler and Duplex ultrasound of middle cerebral artery (MCA) and internal carotid artery (ICA), respectively. From the second minute of hypercapnia onwards, physiological steady-state was apparent, with no subsequent changes in end-tidal P C O 2 , P O 2 or mean arterial pressure. Therefore, CVR measured in the ICA and MCA was stable following the second minute of hypercapnia onwards. Data extraction durations of 30 or 60 s did not give statistically different CVR values. No differences in CVR were detected following the second minute of hypercapnia after accounting for mean arterial pressure via calculated conductance or covariation of mean arterial pressure. These findings demonstrate that, provided the P C O 2 stimulus remains in a steady-state, data extracted from any minute of a CVR test during physiological steady-state conditions produce equivalent CVR values; any change in the CVR value would represent a failure of CVR mechanisms, a change in the magnitude of the stimulus, or measurement error.
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Affiliation(s)
- Jay M J R Carr
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan Campus, Kelowna, British Columbia, Canada
| | - Hannah G Caldwell
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan Campus, Kelowna, British Columbia, Canada
| | - Howard Carter
- Cardiovascular Research Group, School of Human Sciences (Exercise and Sport Science), University of Western Australia, Perth, Australia
| | - Kurt Smith
- Cerebrovascular Health, Exercise, and Environmental Research Sciences Laboratory (CHEERS), School of Exercise Science and Physical Health Education, Faculty of Education, University of Victoria, Victoria, British Columbia, Canada
| | - Michael M Tymko
- Neurovascular Health Laboratory, Faculty of Kinesiology, Sport, & Recreation, University of Alberta, Edmonton, Canada
| | - Daniel J Green
- Cardiovascular Research Group, School of Human Sciences (Exercise and Sport Science), University of Western Australia, Perth, Australia
| | - Philip N Ainslie
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan Campus, Kelowna, British Columbia, Canada
| | - Ryan L Hoiland
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan Campus, Kelowna, British Columbia, Canada.,Department of Anesthesiology, Pharmacology and Therapeutics, Vancouver General Hospital, University of British Columbia, Vancouver, British Columbia, Canada.,Department of Cellular and Physiological Sciences, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada.,International Collaborations on Repair Discoveries (ICORD), University of British Columbia, Vancouver, British Columbia, Canada
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50
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Tallon CM, Smith KJ, Nowak-Flück D, Koziol AV, Rieger MG, Lutes LD, Green DJ, Tremblay MS, Ainslie PN, McManus AM. The influence of sex and maturation on carotid and vertebral artery hemodynamics and associations with free-living (in)activity in 6-17-year-olds. J Appl Physiol (1985) 2021; 131:1575-1583. [PMID: 34617820 DOI: 10.1152/japplphysiol.00537.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We explored the influence of sex and maturation on resting cervical artery hemodynamics (common carotid artery, CCA; internal carotid artery, ICA; and vertebral artery, VA), free-living physical activity, and sedentary behavior in children 6-17 yr of age. In addition, we investigated the relationship between physical activity, sedentary behavior, and cervical artery hemodynamics. Seventy-eight children and adolescents, girls (n = 42; mean age, 11.4 ± 2.5 yr) and boys (n = 36; mean age, 11.0 ± 2.6 yr), completed anthropometric measures, duplex ultrasound assessment of the cervical arteries, and wore an activPAL accelerometer to assess physical activity (indexed by steps/day) and sedentary behavior for 7 days. The ICA and VA diameters were similar between prepubertal and pubertal groups, as was volumetric blood flow (Q); however, the CCA diameter was significantly larger in the pubertal group (P < 0.05). Boys were found to have larger diameters in all cervical arteries than girls, as well as higher QCCA, QICA, and global cerebral blood flow (P < 0.05). The pubertal group was more sedentary (100 min/day more; P < 0.05) and took 3,500 fewer steps/day than the prepubertal group (P < 0.05). Shear rate (SR) and Q of the cervical arteries showed no relationship to physical activity or prolonged bouts of sedentary behavior; however, a significant negative relationship was apparent between total sedentary time and internal carotid artery shear rate (ICASR) after covarying for steps/day and maturation (P < 0.05). These findings provide novel insight into the potential influence sedentary behavior may have on cerebrovascular blood flow in healthy girls and boys.NEW & NOTEWORTHY Cerebral blood flow is known to change with age; however, assessing these age-related changes is complex and requires consideration of pubertal status. This, to our knowledge, is the first study to investigate the influence of sex and maturation on resting cervical artery hemodynamics and subsequently explore associations with physical activity and sedentary behavior in healthy children and adolescents. Our findings suggest that habitual sedentary behavior may influence cervical artery hemodynamics in youth, independent of physical activity, maturation, and sex.
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Affiliation(s)
- Christine M Tallon
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, British Columbia, Canada
| | - Kurt J Smith
- Cerebrovascular Health, Exercise, and Environmental Research Sciences Laboratory, School of Exercise Science and Physical Health Education, University of Victoria, Victoria, British Columbia, Canada
| | - Daniela Nowak-Flück
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, British Columbia, Canada
| | - Alyssa V Koziol
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, British Columbia, Canada
| | - Mathew G Rieger
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, British Columbia, Canada
| | - Lesley D Lutes
- Department of Psychology, Centre for Obesity and Well-Being Research Excellence, University of British Columbia, Kelowna, British Columbia, Canada
| | - Daniel J Green
- School of Human Science (Sport and Exercise Science), The University of Western Australia, Perth, Western Australia, Australia
| | - Mark S Tremblay
- Children's Hospital of Eastern Ontario Research Institute, Ottawa, Ontario, Canada
| | - Philip N Ainslie
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, British Columbia, Canada
| | - Ali M McManus
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, British Columbia, Canada
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