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Danino YM, Rabinovitz R, Kirshenboim I, Palzur E, Pick CG, Ish-Shalom I, Golovkin Y, Arieli Y. Exposure to hyperbaric O 2 levels leads to blood-brain barrier breakdown in rodents. Fluids Barriers CNS 2024; 21:41. [PMID: 38755589 PMCID: PMC11097412 DOI: 10.1186/s12987-024-00543-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2023] [Accepted: 04/24/2024] [Indexed: 05/18/2024] Open
Abstract
INTRODUCTION Hyperbaric oxygen has been used as a medical treatment tool in hyperbaric chambers and is an integral part of professional and combat divers' activity. In extreme cases, exposure to hyperbaric oxygen can develop central nervous system oxygen toxicity (CNS-OT), which leads to seizures and eventually death. CNS-OT is caused by neuronal hyperactivity due to high oxygen levels, potentially damaging brain cells including the blood-brain barrier (BBB). However, the effect of hyperbaric oxygen levels on the healthy BBB has not been characterized directly yet. METHODS Six or three different groups of ~ eight rats or mice, respectively, were exposed to increasing levels of partial pressure of oxygen (0.21 to 5 ATA) in a hyperbaric chamber, followed by MRI scanning with gadolinium. Statistical significance (adjusted p-value ≤ 0.05) was assessed using linear regression and ordinary one-way (rats) or two-way (mice) ANOVA with correction of multiple comparison tests. In rats, the effect of 100% oxygen at 5 ATA was independently validated using FITC-Dextran (5 kDa). Statistical significance (p-value ≤ 0.05) was assessed using Welch's t-test and effect size was calculated by Cohen's D. RESULTS In rats, analyzed MRI scans showed a significant trend of increase in the % gadolinium in brain tissues as a result of hyperbaric oxygen pressures (p-value = 0.0079). The most significant increase was measured at 4 ATA compared to air (adjusted p-value = 0.0461). Significant increased FITC-Dextran levels were measured in the rats' brains under 100% oxygen at 5 ATA versus air (p-value = 0.0327; Effect size = 2.0). In mice, a significant increase in gadolinium penetration into the hippocampus and frontal cortex was measured over time (adjusted p-value < 0.05) under 100% oxygen at 3 and 5 ATA versus air, and between the treatments (adjusted p-value < 0.0001). CONCLUSIONS The BBB is increasingly disrupted due to higher levels of hyperbaric oxygen in rodents, indicating a direct relation between hyperbaric oxygen and BBB dysregulation for the first time. We suggest considering this risk in different diving activities, and protocols using a hyperbaric chamber. On the other hand, this study highlights the potential therapeutic usage of hyperbaric oxygen for controlled drug delivery through the BBB into brain tissues in different brain-related diseases.
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Affiliation(s)
- Yehuda M Danino
- Israel Naval Medical Institute, P.O. Box 8040, Haifa, 31080, Israel
| | | | | | - Eilam Palzur
- Research Institute of Galilee Medical Center, P.O.Box 21, Nahariya, 22100, Israel
| | - Chaim G Pick
- Department of Anatomy and Anthropology, Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel
- Sagol School of Neuroscience, Tel-Aviv University, Tel-Aviv, Israel
- Dr. Miriam and Sheldon G. Adelson Chair and Center for the Biology of Addictive Diseases, Tel-Aviv University, Tel-Aviv, Israel
| | | | - Yana Golovkin
- Israel Naval Medical Institute, P.O. Box 8040, Haifa, 31080, Israel
| | - Yehuda Arieli
- Israel Naval Medical Institute, P.O. Box 8040, Haifa, 31080, Israel.
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2
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Guluzade NA, Huggard JD. Does central chemoreceptor blood flow increase with CO 2 tension? J Physiol 2024. [PMID: 38713148 DOI: 10.1113/jp286058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2024] [Accepted: 04/25/2024] [Indexed: 05/08/2024] Open
Affiliation(s)
- Nasimi A Guluzade
- School of Kinesiology, The University of Western Ontario, London, Ontario, Canada
| | - Joshua D Huggard
- School of Kinesiology, The University of Western Ontario, London, Ontario, Canada
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3
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Simon Machado R, Mathias K, Joaquim L, de Quadros RW, Rezin GT, Petronilho F. Hyperoxia and brain: the link between necessity and injury from a molecular perspective. Neurotox Res 2024; 42:25. [PMID: 38619632 DOI: 10.1007/s12640-024-00702-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2023] [Revised: 11/15/2023] [Accepted: 03/25/2024] [Indexed: 04/16/2024]
Abstract
Oxygen (O2) supplementation is commonly used to treat hypoxia in patients with respiratory failure. However, indiscriminate use can lead to hyperoxia, a condition detrimental to living tissues, particularly the brain. The brain is sensitive to reactive oxygen species (ROS) and inflammation caused by high concentrations of O2, which can result in brain damage and mitochondrial dysfunction, common features of neurodegenerative disorders. Hyperoxia leads to increased production of ROS, causing oxidative stress, an imbalance between oxidants and antioxidants, which can damage tissues. The brain is particularly vulnerable to oxidative stress due to its lipid composition, high O2 consumption rate, and low levels of antioxidant enzymes. Moreover, hyperoxia can cause vasoconstriction and decreased O2 supply to the brain, posing a challenge to redox balance and neurodegenerative processes. Studies have shown that the severity of hyperoxia-induced brain damage varies with inspired O2 concentration and duration of exposure. Therefore, careful evaluation of the balance between benefits and risks of O2 supplementation, especially in clinical settings, is crucial.
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Affiliation(s)
- Richard Simon Machado
- Laboratory of Experimental Neurology, Graduate Program in Health Sciences, Health Sciences Unit, University of Southern Santa Catarina, Criciuma, SC, Brazil.
- Laboratory of Neurobiology of Inflammatory and Metabolic Processes, Graduate Program in Health Sciences, Health Sciences Unit, University of South Santa Catarina, Tubarão, SC, Brazil.
| | - Khiany Mathias
- Laboratory of Experimental Neurology, Graduate Program in Health Sciences, Health Sciences Unit, University of Southern Santa Catarina, Criciuma, SC, Brazil
| | - Larissa Joaquim
- Laboratory of Experimental Neurology, Graduate Program in Health Sciences, Health Sciences Unit, University of Southern Santa Catarina, Criciuma, SC, Brazil
| | | | - Gislaine Tezza Rezin
- Laboratory of Neurobiology of Inflammatory and Metabolic Processes, Graduate Program in Health Sciences, Health Sciences Unit, University of South Santa Catarina, Tubarão, SC, Brazil
| | - Fabricia Petronilho
- Laboratory of Experimental Neurology, Graduate Program in Health Sciences, Health Sciences Unit, University of Southern Santa Catarina, Criciuma, SC, Brazil
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Young DA, Jones PAT, Matenchuk BA, Sivak A, Davenport MH, Steinback CD. The effect of hyperoxia on muscle sympathetic nerve activity: a systematic review and meta-analysis. Clin Auton Res 2024; 34:233-252. [PMID: 38709357 DOI: 10.1007/s10286-024-01033-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2024] [Accepted: 04/09/2024] [Indexed: 05/07/2024]
Abstract
PURPOSE We conducted a meta-analysis to determine the effect of hyperoxia on muscle sympathetic nerve activity in healthy individuals and those with cardio-metabolic diseases. METHODS A comprehensive search of electronic databases was performed until August 2022. All study designs (except reviews) were included: population (humans; apparently healthy or with at least one chronic disease); exposures (muscle sympathetic nerve activity during hyperoxia or hyperbaria); comparators (hyperoxia or hyperbaria vs. normoxia); and outcomes (muscle sympathetic nerve activity, heart rate, blood pressure, minute ventilation). Forty-nine studies were ultimately included in the meta-analysis. RESULTS In healthy individuals, hyperoxia had no effect on sympathetic burst frequency (mean difference [MD] - 1.07 bursts/min; 95% confidence interval [CI] - 2.17, 0.04bursts/min; P = 0.06), burst incidence (MD 0.27 bursts/100 heartbeats [hb]; 95% CI - 2.10, 2.64 bursts/100 hb; P = 0.82), burst amplitude (P = 0.85), or total activity (P = 0.31). In those with chronic diseases, hyperoxia decreased burst frequency (MD - 5.57 bursts/min; 95% CI - 7.48, - 3.67 bursts/min; P < 0.001) and burst incidence (MD - 4.44 bursts/100 hb; 95% CI - 7.94, - 0.94 bursts/100 hb; P = 0.01), but had no effect on burst amplitude (P = 0.36) or total activity (P = 0.90). Our meta-regression analyses identified an inverse relationship between normoxic burst frequency and change in burst frequency with hyperoxia. In both groups, hyperoxia decreased heart rate but had no effect on any measure of blood pressure. CONCLUSION Hyperoxia does not change sympathetic activity in healthy humans. Conversely, in those with chronic diseases, hyperoxia decreases sympathetic activity. Regardless of disease status, resting sympathetic burst frequency predicts the degree of change in burst frequency, with larger decreases for those with higher resting activity.
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Affiliation(s)
- Desmond A Young
- Neurovascular Health Lab, Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Edmonton, AB, Canada
| | - Paris A T Jones
- Neurovascular Health Lab, Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Edmonton, AB, Canada
| | - Brittany A Matenchuk
- Neurovascular Health Lab, Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Edmonton, AB, Canada
- Program for Pregnancy and Postpartum Health, Faculty of Kinesiology, Sport, and Recreation, Women and Children's Health Research Institute, Alberta Diabetes Institute, University of Alberta, Edmonton, AB, Canada
| | - Allison Sivak
- Geoffrey and Robyn Sperber Health Sciences Library, University of Alberta, Edmonton, AB, Canada
| | - Margie H Davenport
- Neurovascular Health Lab, Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Edmonton, AB, Canada
- Program for Pregnancy and Postpartum Health, Faculty of Kinesiology, Sport, and Recreation, Women and Children's Health Research Institute, Alberta Diabetes Institute, University of Alberta, Edmonton, AB, Canada
| | - Craig D Steinback
- Neurovascular Health Lab, Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Edmonton, AB, Canada.
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Salvagno M, Sterchele ED, Zaccarelli M, Mrakic-Sposta S, Welsby IJ, Balestra C, Taccone FS. Oxidative Stress and Cerebral Vascular Tone: The Role of Reactive Oxygen and Nitrogen Species. Int J Mol Sci 2024; 25:3007. [PMID: 38474253 DOI: 10.3390/ijms25053007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Revised: 02/29/2024] [Accepted: 03/02/2024] [Indexed: 03/14/2024] Open
Abstract
The brain's unique characteristics make it exceptionally susceptible to oxidative stress, which arises from an imbalance between reactive oxygen species (ROS) production, reactive nitrogen species (RNS) production, and antioxidant defense mechanisms. This review explores the factors contributing to the brain's vascular tone's vulnerability in the presence of oxidative damage, which can be of clinical interest in critically ill patients or those presenting acute brain injuries. The brain's high metabolic rate and inefficient electron transport chain in mitochondria lead to significant ROS generation. Moreover, non-replicating neuronal cells and low repair capacity increase susceptibility to oxidative insult. ROS can influence cerebral vascular tone and permeability, potentially impacting cerebral autoregulation. Different ROS species, including superoxide and hydrogen peroxide, exhibit vasodilatory or vasoconstrictive effects on cerebral blood vessels. RNS, particularly NO and peroxynitrite, also exert vasoactive effects. This review further investigates the neuroprotective effects of antioxidants, including superoxide dismutase (SOD), vitamin C, vitamin E, and the glutathione redox system. Various studies suggest that these antioxidants could be used as adjunct therapies to protect the cerebral vascular tone under conditions of high oxidative stress. Nevertheless, more extensive research is required to comprehensively grasp the relationship between oxidative stress and cerebrovascular tone, and explore the potential benefits of antioxidants as adjunctive therapies in critical illnesses and acute brain injuries.
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Affiliation(s)
- Michele Salvagno
- Department of Intensive Care, Hôpital Universitaire de Bruxelles (HUB), 1000 Brussels, Belgium
| | - Elda Diletta Sterchele
- Department of Intensive Care, Hôpital Universitaire de Bruxelles (HUB), 1000 Brussels, Belgium
| | - Mario Zaccarelli
- Department of Intensive Care, Hôpital Universitaire de Bruxelles (HUB), 1000 Brussels, Belgium
| | - Simona Mrakic-Sposta
- Institute of Clinical Physiology-National Research Council (CNR-IFC), 20133 Milan, Italy
| | - Ian James Welsby
- Department of Anesthesiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Costantino Balestra
- Environmental, Occupational, Aging (Integrative) Physiology Laboratory, Haute Ecole Bruxelles-Brabant (HE2B), 1160 Brussels, Belgium
- Anatomical Research and Clinical Studies, Vrije Universiteit Brussels (VUB), 1050 Elsene, Belgium
- DAN Europe Research Division (Roseto-Brussels), 1160 Brussels, Belgium
- Motor Sciences Department, Physical Activity Teaching Unit, Université Libre de Bruxelles (ULB), 1050 Brussels, Belgium
| | - Fabio Silvio Taccone
- Department of Intensive Care, Hôpital Universitaire de Bruxelles (HUB), 1000 Brussels, Belgium
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Shaw DM, Harrell JW. Integrating physiological monitoring systems in military aviation: a brief narrative review of its importance, opportunities, and risks. ERGONOMICS 2023; 66:2242-2254. [PMID: 36946542 DOI: 10.1080/00140139.2023.2194592] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Accepted: 03/18/2023] [Indexed: 06/18/2023]
Abstract
Military pilots risk their lives during training and operations. Advancements in aerospace engineering, flight profiles, and mission demands may require the pilot to test the safe limits of their physiology. Monitoring pilot physiology (e.g. heart rate, oximetry, and respiration) inflight is in consideration by several nations to inform pilots of reduced performance capacity and guide future developments in aircraft and life-support system design. Numerous challenges, however, prevent the immediate operationalisation of physiological monitoring sensors, particularly their unreliability in the aerospace environment and incompatibility with pilot clothing and protective equipment. Human performance and behaviour are also highly variable and measuring these in controlled laboratory settings do not mirror the real-world conditions pilots must endure. Misleading or erroneous predictive models are unacceptable as these could compromise mission success and lose operator trust. This narrative review provides an overview of considerations for integrating physiological monitoring systems within the military aviation environment.Practitioner summary: Advancements in military technology can conflictingly enhance and compromise pilot safety and performance. We summarise some of the opportunities, limitations, and risks of integrating physiological monitoring systems within military aviation. Our intent is to catalyse further research and technological development.Abbreviations: AGS: anti-gravity suit; AGSM: anti-gravity straining manoeuvre; A-LOC: almost loss of consciousness; CBF: cerebral blood flow; ECG: electrocardiogram; EEG: electroencephalogram; fNIRS: functional near-infrared spectroscopy; G-forces: gravitational forces; G-LOC: gravity-induced loss of consciousness; HR: heart rate; HRV: heart rate variability; LSS: life-support system; NATO: North Atlantic Treaty Organisation; PE: Physiological Episode; PCO2: partial pressure of carbon dioxide; PO2: partial pressure of oxygen; OBOGS: on board oxygen generating systems; SpO2: peripheral blood haemoglobin-oxygen saturation; STANAG: North Atlantic Treaty Organisation Standardisation Agreement; UPE: Unexplained Physiological Episode; WBV: whole body vibration.
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Affiliation(s)
- David M Shaw
- Aviation Medicine Unit, Royal New Zealand Air Force Base Auckland, Auckland, New Zealand
- School of Sport, Exercise and Nutrition, Massey University, Auckland, New Zealand
| | - John W Harrell
- 711th Human Performance Wing, Air Force Research Laboratory, Wright-Patterson Air Force Base, Dayton, OH, USA
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7
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Xue-Jiao H, Jian-Hua F. A review of the effects of early postnatal hyperoxia exposure on the immature brain. Exp Neurol 2023; 370:114550. [PMID: 37774766 DOI: 10.1016/j.expneurol.2023.114550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Revised: 09/17/2023] [Accepted: 09/25/2023] [Indexed: 10/01/2023]
Abstract
Preterm birth is a public health priority worldwide, with approximately 15 million premature babies born each year. Oxygen supplementation is one of the most common interventions for preterm infants. However, prolonged oxygen inhalation at supraphysiological concentrations can lead to the development of bronchopulmonary dysplasia (BPD). In addition to lifelong pulmonary sequelae, clinical evidence suggests that BPD is associated with adverse neurodevelopmental outcomes, such as motor impairment, cognitive impairment, and behavioral deficits, severely affecting the quality of life of preterm infants. However, the mechanisms underlying the combination of neurodevelopmental impairment with BPD remain unclear. Therefore, in recent years, attention has also been focused on the effects of hyperoxia on brain development in preterm infants. In this review, we outline the pathophysiological mechanisms of brain injury caused by developmental hyperoxia exposure in current animal models and briefly describe the pharmacological therapies that may be applicable to the associated brain injury. Overall, more studies are needed to assess the effects of hyperoxia on the immature brain, particularly combined analyses of the lungs and brain in the same experimental setting, to elucidate the potential causes of combined neurodevelopmental impairment in BPD.
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Affiliation(s)
- Huang Xue-Jiao
- Department of Pediatrics, Shengjing Hospital of China Medical University, Shenyang, China
| | - Fu Jian-Hua
- Department of Pediatrics, Shengjing Hospital of China Medical University, Shenyang, China.
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8
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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] [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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9
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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] [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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Hirunpattarasilp C, Barkaway A, Davis H, Pfeiffer T, Sethi H, Attwell D. Hyperoxia evokes pericyte-mediated capillary constriction. J Cereb Blood Flow Metab 2022; 42:2032-2047. [PMID: 35786054 PMCID: PMC9580167 DOI: 10.1177/0271678x221111598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Oxygen supplementation is regularly prescribed to patients to treat or prevent hypoxia. However, excess oxygenation can lead to reduced cerebral blood flow (CBF) in healthy subjects and worsen the neurological outcome of critically ill patients. Most studies on the vascular effects of hyperoxia focus on arteries but there is no research on the effects on cerebral capillary pericytes, which are major regulators of CBF. Here, we used bright-field imaging of cerebral capillaries and modeling of CBF to show that hyperoxia (95% superfused O2) led to an increase in intracellular calcium level in pericytes and a significant capillary constriction, sufficient to cause an estimated 25% decrease in CBF. Although hyperoxia is reported to cause vascular smooth muscle cell contraction via generation of reactive oxygen species (ROS), endothelin-1 and 20-HETE, we found that increased cytosolic and mitochondrial ROS levels and endothelin release were not involved in the pericyte-mediated capillary constriction. However, a 20-HETE synthesis blocker greatly reduced the hyperoxia-evoked capillary constriction. Our findings establish pericytes as regulators of CBF in hyperoxia and 20-HETE synthesis as an oxygen sensor in CBF regulation. The results also provide a mechanism by which clinically administered oxygen can lead to a worse neurological outcome.
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Affiliation(s)
- Chanawee Hirunpattarasilp
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, UK.,Princess Srisavangavadhana College of Medicine, Chulabhorn Royal Academy, Bangkok, Thailand
| | - Anna Barkaway
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, UK.,Princess Srisavangavadhana College of Medicine, Chulabhorn Royal Academy, Bangkok, Thailand
| | - Harvey Davis
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, UK.,Princess Srisavangavadhana College of Medicine, Chulabhorn Royal Academy, Bangkok, Thailand
| | - Thomas Pfeiffer
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, UK
| | - Huma Sethi
- Division of Neurosurgery, UCL Queen Square Institute of Neurology, Queen Square, London, UK
| | - David Attwell
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, UK
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11
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Machado RS, Tenfen L, Joaquim L, Lanzzarin EVR, Bernardes GC, Bonfante SR, Mathias K, Biehl E, Bagio É, Stork SDS, Denicol T, de Oliveira MP, da Silva MR, Danielski LG, de Quadros RW, Rezin GT, Terra SR, Balsini JN, Gava FF, Petronilho F. Hyperoxia by short-term promotes oxidative damage and mitochondrial dysfunction in rat brain. Respir Physiol Neurobiol 2022; 306:103963. [PMID: 36041716 DOI: 10.1016/j.resp.2022.103963] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 07/29/2022] [Accepted: 08/21/2022] [Indexed: 11/17/2022]
Abstract
Oxygen (O2) therapy is used as a therapeutic protocol to prevent or treat hypoxia. However, a high inspired fraction of O2 (FIO2) promotes hyperoxia, a harmful condition for the central nervous system (CNS). The present study evaluated parameters of oxidative stress and mitochondrial dysfunction in the brain of rats exposed to different FIO2. Male Wistar rats were exposed to hyperoxia (FIO2 40 % and 60 %) compared to the control group (FIO2 21 %) for 2 h. Oxidative stress, neutrophilic infiltration, and mitochondrial respiratory chain enzymes were determined in the hippocampus, striatum, cerebellum, cortex, and prefrontal cortex after O2 exposure. The animals exposed to hyperoxia showed increased lipid peroxidation, formation of carbonyl proteins, N/N concentration, and neutrophilic infiltration in some brain regions, like hippocampus, striatum, and cerebellum being the most affected. Furthermore, CAT activity and activity of mitochondrial enzyme complexes were also altered after exposure to hyperoxia. Rats exposed to hyperoxia showed increase in oxidative stress parameters and mitochondrial dysfunction in brain structures.
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Affiliation(s)
- Richard Simon Machado
- Laboratory of Neurobiology of Inflammatory and Metabolic Processes, Graduate Program in Health Sciences, Health Sciences Unit, University of South Santa Catarina, Tubarão, SC, Brazil
| | - Leonardo Tenfen
- Laboratory of Neurobiology of Inflammatory and Metabolic Processes, Graduate Program in Health Sciences, Health Sciences Unit, University of South Santa Catarina, Tubarão, SC, Brazil
| | - Larissa Joaquim
- Laboratory of Neurobiology of Inflammatory and Metabolic Processes, Graduate Program in Health Sciences, Health Sciences Unit, University of South Santa Catarina, Tubarão, SC, Brazil
| | - Everton Venicius Rosa Lanzzarin
- Laboratory of Neurobiology of Inflammatory and Metabolic Processes, Graduate Program in Health Sciences, Health Sciences Unit, University of South Santa Catarina, Tubarão, SC, Brazil
| | - Gabriela Costa Bernardes
- Laboratory of Neurobiology of Inflammatory and Metabolic Processes, Graduate Program in Health Sciences, Health Sciences Unit, University of South Santa Catarina, Tubarão, SC, Brazil
| | - Sandra Regina Bonfante
- Laboratory of Neurobiology of Inflammatory and Metabolic Processes, Graduate Program in Health Sciences, Health Sciences Unit, University of South Santa Catarina, Tubarão, SC, Brazil
| | - Khiany Mathias
- Laboratory of Neurobiology of Inflammatory and Metabolic Processes, Graduate Program in Health Sciences, Health Sciences Unit, University of South Santa Catarina, Tubarão, SC, Brazil
| | - Erica Biehl
- Laboratory of Neurobiology of Inflammatory and Metabolic Processes, Graduate Program in Health Sciences, Health Sciences Unit, University of South Santa Catarina, Tubarão, SC, Brazil
| | - Érick Bagio
- Laboratory of Neurobiology of Inflammatory and Metabolic Processes, Graduate Program in Health Sciences, Health Sciences Unit, University of South Santa Catarina, Tubarão, SC, Brazil
| | - Solange de Souza Stork
- Laboratory of Neurobiology of Inflammatory and Metabolic Processes, Graduate Program in Health Sciences, Health Sciences Unit, University of South Santa Catarina, Tubarão, SC, Brazil
| | - Tais Denicol
- Laboratory of Neurobiology of Inflammatory and Metabolic Processes, Graduate Program in Health Sciences, Health Sciences Unit, University of South Santa Catarina, Tubarão, SC, Brazil
| | - Mariana Pacheco de Oliveira
- Laboratory of Neurobiology of Inflammatory and Metabolic Processes, Graduate Program in Health Sciences, Health Sciences Unit, University of South Santa Catarina, Tubarão, SC, Brazil
| | - Mariella Reinol da Silva
- Laboratory of Neurobiology of Inflammatory and Metabolic Processes, Graduate Program in Health Sciences, Health Sciences Unit, University of South Santa Catarina, Tubarão, SC, Brazil
| | - Lucinéia Gainski Danielski
- Laboratory of Experimental Neurology, Graduate Program in Health Sciences, University of Southern Santa Catarina, Criciuma, SC, Brazil
| | | | - Gislaine Tezza Rezin
- Laboratory of Neurobiology of Inflammatory and Metabolic Processes, Graduate Program in Health Sciences, Health Sciences Unit, University of South Santa Catarina, Tubarão, SC, Brazil
| | - Silvia Resende Terra
- Department of Biochemistry, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Jairo Nunes Balsini
- Laboratory of Neurobiology of Inflammatory and Metabolic Processes, Graduate Program in Health Sciences, Health Sciences Unit, University of South Santa Catarina, Tubarão, SC, Brazil
| | - Fernanda Frederico Gava
- Laboratory of Experimental Neurology, Graduate Program in Health Sciences, University of Southern Santa Catarina, Criciuma, SC, Brazil
| | - Fabricia Petronilho
- Laboratory of Experimental Neurology, Graduate Program in Health Sciences, University of Southern Santa Catarina, Criciuma, SC, Brazil.
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12
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Garcia VP, Mattos JD, Mentzinger J, Leite PEC, Rocha HNM, Campos MO, Rocha MP, Mansur DE, Secher NH, Nóbrega ACL, Fernandes IA, Rocha NG. Short isocapnic hyperoxia affects indices of vascular remodeling and intercellular adhesion molecules in healthy men. Braz J Med Biol Res 2022; 55:e12110. [PMID: 35703682 PMCID: PMC9200048 DOI: 10.1590/1414-431x2022e12110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2022] [Accepted: 04/11/2022] [Indexed: 11/22/2022] Open
Abstract
In preparation for tracheal intubation during induction of anesthesia, the patient may be ventilated with 100% oxygen. To investigate the impact of acute isocapnic hyperoxia on endothelial activation and vascular remodeling, ten healthy young men (24±3 years) were exposed to 5-min normoxia (21% O2) and 10-min hyperoxia trials (100% O2). During hyperoxia, intercellular adhesion molecules (ICAM-1) (hyperoxia: 4.16±0.85 vs normoxia: 3.51±0.84 ng/mL, P=0.04) and tissue inhibitor matrix metalloproteinase 1 (TIMP-1) (hyperoxia: 8.40±3.84 vs normoxia: 5.73±2.15 pg/mL, P=0.04) increased, whereas matrix metalloproteinase (MMP-9) activity (hyperoxia: 0.53±0.11 vs normoxia: 0.68±0.18 A.U., P=0.03) decreased compared to the normoxia trial. We concluded that even short exposure to 100% oxygen may affect endothelial activation and vascular remodeling.
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Affiliation(s)
- V P Garcia
- Laboratório de Ciências do Exercício, Departamento de Fisiologia e Farmacologia, Universidade Federal Fluminense, Niterói, RJ, Brasil
| | - J D Mattos
- Laboratório de Ciências do Exercício, Departamento de Fisiologia e Farmacologia, Universidade Federal Fluminense, Niterói, RJ, Brasil
| | - J Mentzinger
- Laboratório de Ciências do Exercício, Departamento de Fisiologia e Farmacologia, Universidade Federal Fluminense, Niterói, RJ, Brasil
| | - P E C Leite
- Laboratório de Bioengenharia e Toxicologia in Vitro, Instituto Nacional de Qualidade e Tecnologia Metrológica, Duque de Caxias, RJ, Brasil
| | - H N M Rocha
- Laboratório de Ciências do Exercício, Departamento de Fisiologia e Farmacologia, Universidade Federal Fluminense, Niterói, RJ, Brasil
| | - M O Campos
- Laboratório de Ciências do Exercício, Departamento de Fisiologia e Farmacologia, Universidade Federal Fluminense, Niterói, RJ, Brasil
| | - M P Rocha
- Laboratório de Ciências do Exercício, Departamento de Fisiologia e Farmacologia, Universidade Federal Fluminense, Niterói, RJ, Brasil
| | - D E Mansur
- Laboratório de Ciências do Exercício, Departamento de Fisiologia e Farmacologia, Universidade Federal Fluminense, Niterói, RJ, Brasil
| | - N H Secher
- Department of Anesthesia, Rigshospitalet, Institute of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
| | - A C L Nóbrega
- Laboratório de Ciências do Exercício, Departamento de Fisiologia e Farmacologia, Universidade Federal Fluminense, Niterói, RJ, Brasil
| | - I A Fernandes
- NeuroVASQ - Laboratório de Fisiologia Integrativa, Faculdade de Educação Física, Universidade de Brasília, Brasília, DF, Brasil
| | - N G Rocha
- Laboratório de Ciências do Exercício, Departamento de Fisiologia e Farmacologia, Universidade Federal Fluminense, Niterói, RJ, Brasil
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13
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The Effect of Hyperoxemia on Neurological Outcomes of Adult Patients: A Systematic Review and Meta-Analysis. Neurocrit Care 2022; 36:1027-1043. [PMID: 35099713 PMCID: PMC9110471 DOI: 10.1007/s12028-021-01423-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Accepted: 12/14/2021] [Indexed: 12/29/2022]
Abstract
Hyperoxemia commonly occurs in clinical practice and is often left untreated. Many studies have shown increased mortality in patients with hyperoxemia, but data on neurological outcome in these patients are conflicting, despite worsened neurological outcome found in preclinical studies. To investigate the association between hyperoxemia and neurological outcome in adult patients, we performed a systematic review and meta-analysis of observational studies. We searched MEDLINE, Embase, Scopus, Web of Science, Cumulative Index to Nursing and Allied Health Literature, and ClinicalTrials.gov from inception to May 2020 for observational studies correlating arterial oxygen partial pressure (PaO2) with neurological status in adults hospitalized with acute conditions. Studies of chronic pulmonary disease or hyperbaric oxygenation were excluded. Relative risks (RRs) were pooled at the study level by using a random-effects model to compare the risk of poor neurological outcome in patients with hyperoxemia and patients without hyperoxemia. Sensitivity and subgroup analyses and assessments of publication bias and risk of bias were performed. Maximum and mean PaO2 in patients with favorable and unfavorable outcomes were compared using standardized mean difference (SMD). Of 6255 records screened, 32 studies were analyzed. Overall, hyperoxemia was significantly associated with an increased risk of poor neurological outcome (RR 1.13, 95% confidence interval [CI] 1.05-1.23, statistical heterogeneity I2 58.8%, 22 studies). The results were robust across sensitivity analyses. Patients with unfavorable outcome also showed a significantly higher maximum PaO2 (SMD 0.17, 95% CI 0.04-0.30, I2 78.4%, 15 studies) and mean PaO2 (SMD 0.25, 95% CI 0.04-0.45, I2 91.0%, 13 studies). These associations were pronounced in patients with subarachnoid hemorrhage (RR 1.34, 95% CI 1.14-1.56) and ischemic stroke (RR 1.41, 95% CI 1.14-1.74), but not in patients with cardiac arrest, traumatic brain injury, or following cardiopulmonary bypass. Hyperoxemia is associated with poor neurological outcome, especially in patients with subarachnoid hemorrhage and ischemic stroke. Although our study cannot establish causality, PaO2 should be monitored closely because hyperoxemia may be associated with worsened patient outcome and consequently affect the patient's quality of life.
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14
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Ahn J, Mastorakos P, Sokolowski JD, Chen CJ, Kellogg R, Park MS. Effects of hyperoxemia on aneurysmal subarachnoid hemorrhage outcomes: a systematic review and meta-analysis. Neurosurg Focus 2022; 52:E7. [PMID: 35231897 DOI: 10.3171/2021.12.focus21660] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Accepted: 12/10/2021] [Indexed: 12/12/2022]
Abstract
OBJECTIVE In recent years, hyperoxemia in the intensive care unit has received attention as potentially contributing to negative outcomes in the setting of cardiac arrest, ischemic stroke, and traumatic brain injury. The authors sought to evaluate whether hyperoxemia contributes to worse outcomes in the setting of aneurysmal subarachnoid hemorrhage (aSAH) and to summarize suggested pathophysiological mechanisms. METHODS A systematic literature review was conducted without date restrictions on the PubMed and Web of Science databases on September 15, 2021. All studies that assessed the relationship between patients treated for aSAH and hyperoxemia were eligible independent of the criteria used to define hyperoxemia. All nonclinical studies and studies that did not report outcome data specific to patients with aSAH were excluded. A total of 102 records were found and screened, resulting in assessment of 10 full-text studies, of which 7 met eligibility criteria. Risk of bias was assessed using the Downs and Black checklist. A meta-analysis on the pooled 2602 patients was performed, and forest plots were constructed. Additionally, a review of the literature was performed to summarize available data regarding the pathophysiology of hyperoxemia. RESULTS The included studies demonstrated an association between hyperoxemia and increased morbidity and mortality following aSAH. The criteria used to determine hyperoxemia varied among studies. Pooling of univariate data showed hyperoxemia to be associated with poor neurological outcome (OR 2.26, 95% CI 1.66-3.07; p < 0.001), delayed cerebral ischemia (DCI) (OR 1.91, 95% CI 1.31-2.78; p < 0.001), and increased incidence of poor neurological outcome or mortality as a combined endpoint (OR 2.36, 95% CI 1.87-2.97; p < 0.001). Pooling of multivariable effect sizes showed the same relationship for poor neurological outcome (OR 1.28, 95% CI 1.07-1.55; p = 0.01) and poor neurological outcome and mortality as a combined endpoint (OR 1.17, 95% CI 1.11-1.23; p < 0.001). Additionally, review of preclinical studies underlined the contribution of oxidative stress due to hyperoxemia to acute secondary brain injury and DCI. CONCLUSIONS Reported outcomes from the available studies have indicated that hyperoxemia is associated with worse neurological outcome, mortality, and DCI. These findings provide a general guideline toward avoiding hyperoxemia in the acute setting of aSAH. Further studies are needed to determine the optimal ventilation and oxygenation parameters for acute management of this patient population.
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Affiliation(s)
- Jungeun Ahn
- 1School of Medicine, University of Virginia, Charlottesville, Virginia
| | - Panagiotis Mastorakos
- 2Department of Neurosurgery, University of Virginia Health System, Charlottesville, Virginia; and
| | - Jennifer D Sokolowski
- 2Department of Neurosurgery, University of Virginia Health System, Charlottesville, Virginia; and
| | - Ching-Jen Chen
- 3Department of Neurosurgery, Thomas Jefferson University Hospital, Philadelphia, Pennsylvania
| | - Ryan Kellogg
- 2Department of Neurosurgery, University of Virginia Health System, Charlottesville, Virginia; and
| | - Min S Park
- 2Department of Neurosurgery, University of Virginia Health System, Charlottesville, Virginia; and
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15
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Rezende C, Oliveira GVD, Volino-Souza M, Castro P, Murias JM, Alvares TS. Turmeric root extract supplementation improves pre-frontal cortex oxygenation and blood volume in older males and females: a randomised cross-over, placebo-controlled study. Int J Food Sci Nutr 2021; 73:274-283. [PMID: 34551650 DOI: 10.1080/09637486.2021.1972411] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Ageing is associated with endothelial dysfunction and reduced cerebral blood flow and oxygenation. The present study aimed to investigate whether turmeric supplementation could improve cerebral oxygenation and blood volume during brain activation via dynamic handgrip exercise in older males and females. Twelve older males and females were studied using a double-blind, placebo-controlled, cross-over design. Participants ingested turmeric root extract or placebo. Heart rate and blood pressure were measured before and 2 hours after supplementation. Afterward, the exercise protocol was started, and cerebral oxygenation and blood volume were evaluated. During exercise, changes in cerebral oxygenation were higher after turmeric extract supplementation, as was blood volume compared to placebo. Changes in heart rate, systolic blood pressure, and diastolic blood pressure were not significant. The current findings indicate the potential for curcumin as an intervention for improving cerebral oxygenation and blood volume changes in older males and females. Clinical trial registry: NCT04119752.
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Affiliation(s)
- Cristina Rezende
- Nutrition and Exercise Metabolism Research Group, Federal University of Rio de Janeiro Campus Macaé, Rio de Janeiro, Brazil
| | - Gustavo Vieira de Oliveira
- Nutrition and Exercise Metabolism Research Group, Federal University of Rio de Janeiro Campus Macaé, Rio de Janeiro, Brazil
| | - Mônica Volino-Souza
- Nutrition and Exercise Metabolism Research Group, Federal University of Rio de Janeiro Campus Macaé, Rio de Janeiro, Brazil
| | - Patrícia Castro
- Nutrition and Exercise Metabolism Research Group, Federal University of Rio de Janeiro Campus Macaé, Rio de Janeiro, Brazil
| | | | - Thiago Silveira Alvares
- Nutrition and Exercise Metabolism Research Group, Federal University of Rio de Janeiro Campus Macaé, Rio de Janeiro, Brazil
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16
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Fernandes IA, Mattos JD, Campos MO, Rocha MP, Mansur DE, Rocha HM, Garcia VP, Alvares T, Secher NH, Nóbrega ACL. Reactive oxygen species play a modulatory role in the hyperventilatory response to poikilocapnic hyperoxia in humans. J Physiol 2021; 599:3993-4007. [PMID: 34245024 DOI: 10.1113/jp281635] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Accepted: 07/08/2021] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS The proposed mechanism for the increased ventilation in response to hyperoxia includes a reduced brain CO2 -[H+ ] washout-induced central chemoreceptor stimulation that results from a decrease in cerebral perfusion and the weakening of the CO2 affinity for haemoglobin. Nonetheless, hyperoxia also results in excessive brain reactive oxygen species (ROS) formation/accumulation, which hypothetically increases central respiratory drive and causes hyperventilation. We then quantified ventilation, cerebral perfusion/metabolism, arterial/internal jugular vein blood gases and oxidant/antioxidant biomarkers in response to hyperoxia during intravenous infusion of saline or ascorbic acid to determine whether excessive ROS production/accumulation contributes to the hyperoxia-induced hyperventilation in humans. Ascorbic acid infusion augmented the antioxidant defence levels, blunted ROS production/accumulation and minimized both the reduction in cerebral perfusion and the increase in ventilation observed during saline infusion. Hyperoxic hyperventilation seems to be mediated by central chemoreceptor stimulation provoked by the interaction between an excessive ROS production/accumulation and reduced brain CO2 -[H+ ] washout. ABSTRACT The hypothetical mechanism for the increase in ventilation ( V ̇ E ) in response to hyperoxia (HX) includes central chemoreceptor stimulation via reduced CO2 -[H+ ] washout. Nonetheless, hyperoxia disturbs redox homeostasis and raises the hypothesis that excessive brain reactive oxygen species (ROS) production/accumulation may increase the sensitivity to CO2 or even solely activate the central chemoreceptors, resulting in hyperventilation. To determine the mechanism behind the HX-evoked increase in V ̇ E , 10 healthy men (24 ± 4 years) underwent 10 min trials of HX under saline and ascorbic acid infusion. V ̇ E , arterial and right internal right jugular vein (ijv) partial pressure for oxygen (PO2 ) and CO2 (PCO2 ), pH, oxidant (8-isoprostane) and antioxidant (ascorbic acid) markers, as well as cerebral blood flow (CBF) (Duplex ultrasonography), were quantified at each hyperoxic trial. HX evoked an increase in arterial partial pressure for oxygen, followed by a hyperventilatory response, a reduction in CBF, an increase in arterial 8-isoprostane, and unchanged PijvCO2 and ijv pH. Intravenous ascorbic acid infusion augmented the arterial antioxidant marker, blunted the increase in arterial 8-isoprostane and attenuated both the reduction in CBF and the HX-induced hyperventilation. Although ascorbic acid infusion resulted in a slight increase in PijvCO2 and a substantial decrease in ijv pH, when compared with the saline bout, HX evoked a similar reduction and a paired increase in the trans-cerebral exchanges for PCO2 and pH, respectively. These findings indicate that the poikilocapnic hyperoxic hyperventilation is likely mediated via the interaction of the acidic brain interstitial fluid and an increase in central chemoreceptor sensitivity to CO2 , which, in turn, seems to be evoked by the excessive ROS production/accumulation.
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Affiliation(s)
- Igor A Fernandes
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, Brazil
| | - João D Mattos
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, Brazil
| | - Monique O Campos
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, Brazil
| | - Marcos P Rocha
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, Brazil
| | - Daniel E Mansur
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, Brazil
| | - Helena M Rocha
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, Brazil
| | - Vinicius P Garcia
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, Brazil
| | | | - Niels H Secher
- Department of Anaesthesia, Rigshospitalet, Institute for Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Antonio C L Nóbrega
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, Brazil
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17
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Abstract
OBJECTIVE The inability of the organism to appropriately respond to hypoxia results in abnormal cell metabolism and function. Hypoxia-induced angiogenesis seems to be suppressed in experimental models of hypertension; however, this hypothesis has not been tested in humans. We examined changes in endothelial biomarkers and vascular chemoattraction/angiogenic capacity in response to isocapnic hypoxia in hypertensive men. METHODS Twelve normotensive (38 ± 10 years) and nine hypertensive men (45 ± 11 years) were exposed to 5-min trials of normoxia (21% O2) and isocapnic hypoxia (10% O2). During the last minute of each trial, venous blood was drawn. Endothelial progenitor cells (EPCs; CD45/CD34/VEGFR2), endothelial microvesicles (apoptotic EMVs, CD42b/CD31/AnnexinV; endothelial activation, CD62E/CD144), nitrite, vascular endothelial growth factor (VEGF), and stromal cell-derived factor 1 (SDF-1) were measured. RESULTS During normoxia, EPCs, nitrite, endothelial activation, and SDF-1 were similar between groups, whereas VEGF was lower (P = 0.02) and apoptotic EMVs tended to increase (P = 0.07) in hypertensive men. During isocapnic hypoxia, endothelial activation increased in both groups (normotensive, P = 0.007 vs. normoxia; hypertensive, P = 0.006 vs. normoxia), whereas EMVs were higher only in the hypertensive group (P = 0.03 vs. normotensive). EPCs (P = 0.01 vs. normoxia; P = 0.03 vs. hypertensive men), NO (P = 0.01 vs. normoxia; P = 0.04 vs. hypertensive), and VEGF (P = 0.02 vs. normoxia; P = 0.0005 vs. hypertensive) increased only in normotensive individuals in response to isocapnic hypoxia. SDF-1 did not change in either group. CONCLUSION These results suggest that hypertension-induced impairment in angiogenesis in response to isocapnic hypoxia is related to disrupted NO bioavailability, VEGF chemotactic signaling, and EPC mobilization.
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18
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Duncan JW, Azubuike D, Booz GW, Fisher B, Williams JM, Fan F, Ibrahim T, LaMarca B, Cunningham MW. Angiotensin II type 1 receptor autoantibody blockade improves cerebral blood flow autoregulation and hypertension in a preclinical model of preeclampsia. Hypertens Pregnancy 2020; 39:451-460. [PMID: 33119997 DOI: 10.1080/10641955.2020.1833215] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Introduction:Women with preeclampsia (PE) and reduced uterine perfusion pressure (RUPP) pre-clinical rat model of PE have elevated angiotensin II type 1 receptor agonistic autoantibodies (AT1-AA) and cerebrovascular dysfunction. Methods:Sprague Dawley rats had RUPP surgery with/without AT1-AA inhibitor ('n7AAc'144 μg/day) osmotic minipumps. Mean arterial pressure (MAP), CBF autoregulation, blood brain barrier (BBB) permeability, cerebral edema, oxidative stress, and eNOS were assessed. Results:'n7AAc' improved MAP, restored CBF autoregulation, prevented cerebral edema, elevated oxidative stress, and increased phosphorylated eNOS protein in RUPP rats. Conclusion:Inhibiting the AT1-AA in placental ischemic rats prevents hypertension, cerebrovascular dysfunction, and improves cerebral metabolic function.
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Affiliation(s)
- Jeremy W Duncan
- Department of Physiology and Biophysics, University of Mississippi Medical Center , Jackson, MS, USA
| | - Daniel Azubuike
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center , Jackson, MS, USA
| | - George W Booz
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center , Jackson, MS, USA
| | - Brandon Fisher
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center , Jackson, MS, USA
| | - Jan M Williams
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center , Jackson, MS, USA
| | - Fan Fan
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center , Jackson, MS, USA
| | - Tarek Ibrahim
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center , Jackson, MS, USA
| | - Babbette LaMarca
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center , Jackson, MS, USA.,Department of Obstetrics and Gynecology, University of Mississippi Medical Center , Jackson, MS, USA
| | - Mark W Cunningham
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center , Jackson, MS, USA
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19
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Damato EG, Flak TA, Mayes RS, Strohl KP, Ziganti AM, Abdollahifar A, Flask CA, LaManna JC, Decker MJ. Neurovascular and cortical responses to hyperoxia: enhanced cognition and electroencephalographic activity despite reduced perfusion. J Physiol 2020; 598:3941-3956. [PMID: 33174711 DOI: 10.1113/jp279453] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 06/02/2020] [Indexed: 12/11/2022] Open
Abstract
KEY POINTS Extreme aviation is accompanied by ever-present risks of hypobaric hypoxia and decompression sickness. Neuroprotection against those hazards is conferred through fractional inspired oxygen ( F I , O 2 ) concentrations of 60-100% (hyperoxia). Hyperoxia reduces global cerebral perfusion (gCBF), increases reactive oxygen species within the brain and leads to cell death within the hippocampus. However, an understanding of hyperoxia's effect on cortical activity and concomitant levels of cognitive performance is lacking. This limits our understanding of whether hyperoxia could lower the brain's threshold of tolerance to physiological stressors inherent to extreme aviation, such as high gravitational forces. This study aimed to quantify the impact of hyperoxia upon global cerebral perfusion (gCBF), cognitive performance and cortical electroencephalography (EEG). Hyperoxia evoked a rapid reduction in gCBF, yet cognitive performance and vigilance were enhanced. EEG measurements revealed enhanced alpha power, suggesting less desynchrony, within the cortical temporal regions. Collectively, this work suggests hyperoxia-induced brain hypoperfusion is accompanied by enhanced cognitive processing and cortical arousal. ABSTRACT Extreme aviators continually inspire hyperoxic gas to mitigate risk of hypoxia and decompression injury. This neuroprotection carries a physiological cost: reduced cerebral perfusion (CBF). As reduced CBF may increase vulnerability to ever-present physiological challenges during extreme aviation, we defined the magnitude and duration of hyperoxia-induced changes in CBF, cortical electrical activity and cognition in 30 healthy males and females. Magnetic resonance imaging with pulsed arterial spin labelling provided serial measurements of global CBF (gCBF), first during exposure to 21% inspired oxygen ( F I , O 2 ) followed by a 30-min exposure to 100% F I , O 2 . High-density EEG facilitated characterization of cortical activity during assessment of cognitive performance, also measured during exposure to 21% and 100% F I , O 2 . Acid-base physiology was measured with arterial blood gases. We found that exposure to 100% F I , O 2 reduced gCBF to 63% of baseline values across all participants. Cognitive performance testing at 21% F I , O 2 was accompanied by increased theta and beta power with decreased alpha power across multiple cortical areas. During cognitive testing at 100% F I , O 2 , alpha activity was less desynchronized within the temporal regions than at 21% F I , O 2 . The collective hyperoxia-induced changes in gCBF, cognitive performance and EEG were similar across observed partial pressures of arterial oxygen ( P a O 2 ), which ranged between 276-548 mmHg, and partial pressures of arterial carbon dioxide ( P aC O 2 ), which ranged between 34-50 mmHg. Sex did not influence gCBF response to 100% F I , O 2 . Our findings suggest hyperoxia-induced reductions in gCBF evoke enhanced levels of cortical arousal and cognitive processing, similar to those occurring during a perceived threat.
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Affiliation(s)
- Elizabeth G Damato
- Case Western Reserve University, Cleveland, OH, 44106, USA.,Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH, 44106, USA.,School of Nursing, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Tod A Flak
- Bioautomatix, LLC, Shaker Heights, OH, 44122, USA
| | - Ryan S Mayes
- United States Air Force, 711th Human Performance Wing, USAF School of Aerospace Medicine, Wright-Patterson AFB, OH, 45433, USA
| | - Kingman P Strohl
- Case Western Reserve University, Cleveland, OH, 44106, USA.,Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH, 44106, USA.,Louis Stokes Cleveland Veterans Administration Medical Center, Cleveland, OH, 44106, USA
| | - Aemilee M Ziganti
- Case Western Reserve University, Cleveland, OH, 44106, USA.,Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Alireza Abdollahifar
- Case Western Reserve University, Cleveland, OH, 44106, USA.,Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Chris A Flask
- Case Western Reserve University, Cleveland, OH, 44106, USA.,Department of Radiology, School of Medicine, Cleveland, OH, 44106, USA
| | - Joseph C LaManna
- Case Western Reserve University, Cleveland, OH, 44106, USA.,Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Michael J Decker
- Case Western Reserve University, Cleveland, OH, 44106, USA.,Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH, 44106, USA
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20
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Caldwell HG, Hoiland RL, Barak OF, Mijacika T, Burma JS, Dujić Ž, Ainslie PN. Alterations in resting cerebrovascular regulation do not affect reactivity to hypoxia, hyperoxia or neurovascular coupling following a SCUBA dive. Exp Physiol 2020; 105:1540-1549. [PMID: 32618374 DOI: 10.1113/ep088746] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Accepted: 06/29/2020] [Indexed: 12/12/2022]
Abstract
NEW FINDINGS What is the central question of this study? What are the characteristics of cerebral blood flow (CBF) regulation following a single SCUBA dive to a depth of 18 m sea water with a 47 min bottom time. What is the main finding and its importance? Acute alterations in CBF regulation at rest, including extra-cranial vasodilatation, reductions in shear patterns and elevations in intra-cranial blood velocity were observed at rest following a single SCUBA dive. These subtle changes in CBF regulation did not translate into any functional changes in cerebrovascular reactivity to hypoxia or hyperoxia, or neurovascular coupling following a single SCUBA dive. ABSTRACT Reductions in vascular function during a SCUBA dive - due to hyperoxia-induced oxidative stress, arterial and venous gas emboli and altered endothelial integrity - may also extend to the cerebrovasculature following return to the surface. This study aimed to characterize cerebral blood flow (CBF) regulation following a single SCUBA dive to a depth of 18 m sea water with a 47 min bottom time. Prior to and following the dive, participants (n = 11) completed (1) resting CBF in the internal carotid (ICA) and vertebral (VA) arteries (duplex ultrasound) and intra-cranial blood velocity (v) of the middle and posterior cerebral arteries (MCAv and PCAv, respectively) (transcranial Doppler ultrasound); (2) cerebrovascular reactivity to acute poikilocapnic hypoxia (i.e. F I O 2 , 0.10) and hyperoxia (i.e. F I O 2 , 1.0); and (3) neurovascular coupling (NVC; regional CBF response to local increases in cerebral metabolism). Global CBF, cerebrovascular reactivity to hypoxia and hyperoxia, and NVC were unaltered following a SCUBA dive (all P > 0.05); however, there were subtle changes in other cerebrovascular metrics post-dive, including reductions in ICA (-13 ± 8%, P = 0.003) and VA (-11 ± 14%, P = 0.021) shear rate, lower ICAv (-10 ± 9%, P = 0.008) and VAv (-9 ± 14%, P = 0.028), increases in ICA diameter (+4 ± 5%, P = 0.017) and elevations in PCAv (+10 ± 19%, P = 0.047). Although we observed subtle alterations in CBF regulation at rest, these changes did not translate into any functional changes in cerebrovascular reactivity to hypoxia or hyperoxia, or NVC. Whether prolonged exposure to hyperoxia and hyperbaria during longer, deeper, colder and/or repetitive SCUBA dives would provoke changes to the cerebrovasculature requires further investigation.
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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, Canada
| | - Ryan L Hoiland
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Okanagan, Kelowna, Canada
| | - Otto F Barak
- Department of Physiology, Faculty of Medicine, University of Novi Sad, Novi Sad, Serbia.,Faculty of Sports and Physical Education, University of Novi Sad, Novi Sad, Serbia
| | - Tanja Mijacika
- Department of Integrative Physiology, University of Split School of Medicine, Split, Croatia
| | - Joel S Burma
- Sport Injury Prevention Research Centre, Faculty of Kinesiology, University of Calgary, Calgary, Canada
| | - Željko Dujić
- Department of Integrative Physiology, University of Split School of Medicine, Split, Croatia
| | - 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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21
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Ma Y, Mazerolle EL, Cho J, Sun H, Wang Y, Pike GB. Quantification of brain oxygen extraction fraction using QSM and a hyperoxic challenge. Magn Reson Med 2020; 84:3271-3285. [DOI: 10.1002/mrm.28390] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 05/19/2020] [Accepted: 06/01/2020] [Indexed: 12/24/2022]
Affiliation(s)
- Yuhan Ma
- Department of Biomedical Engineering and McConnell Brain Imaging Centre McGill University Montréal Quebec Canada
| | - Erin L. Mazerolle
- Department of Radiology and Hotchkiss Brain Institute University of Calgary Calgary Alberta Canada
| | - Junghun Cho
- Department of Biomedical Engineering Cornell University Ithaca New York USA
| | - Hongfu Sun
- Department of Radiology and Hotchkiss Brain Institute University of Calgary Calgary Alberta Canada
- School of Information Technology and Electrical Engineering University of Queensland Brisbane Australia
| | - Yi Wang
- Department of Biomedical Engineering Cornell University Ithaca New York USA
- Department of Radiology Weill Cornell Medical College New York New York USA
| | - G. Bruce Pike
- Department of Biomedical Engineering and McConnell Brain Imaging Centre McGill University Montréal Quebec Canada
- Department of Radiology and Hotchkiss Brain Institute University of Calgary Calgary Alberta Canada
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22
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Rocha MP, Campos MO, Mattos JD, Mansur DE, Rocha HNM, Secher NH, Nóbrega ACL, Fernandes IA. K ATP channels modulate cerebral blood flow and oxygen delivery during isocapnic hypoxia in humans. J Physiol 2020; 598:3343-3356. [PMID: 32463117 DOI: 10.1113/jp279751] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Accepted: 05/11/2020] [Indexed: 12/20/2022] Open
Abstract
KEY POINTS ATP-sensitive K+ (KATP ) channels mediate hypoxia-induced cerebral vasodilatation and hyperperfusion in animals. We tested whether KATP channels blockade affects the increase in human cerebral blood flow (CBF) and the maintenance of oxygen delivery (CDO2 ) during hypoxia. Hypoxia-induced increases in the anterior circulation and total cerebral perfusion were attenuated under KATP channels blockade affecting the relative changes of brain oxygen delivery. Therefore, in humans, KATP channels activation modulates the vascular tone in the anterior circulation of the brain, contributing to CBF and CDO2 responses to hypoxia. ABSTRACT ATP-sensitive K+ (KATP ) channels mediate hypoxia-induced cerebral vasodilatation and hyperperfusion in animals. We tested whether KATP channels blockade affects the increase in cerebral blood flow (CBF) and the maintenance of oxygen delivery (CDO2 ) during hypoxia in humans. Nine healthy men were exposed to 5-min trials of normoxia and isocapnic hypoxia (IHX, 10% O2 ) before (BGB) and 3 h after glibenclamide ingestion (AGB). Mean arterial pressure (MAP), arterial saturation ( S a O 2 ), partial pressure of oxygen ( P a O 2 ) and carbon dioxide ( P aC O 2 ), internal carotid artery blood flow (ICABF), vertebral artery blood flow (VABF), total (t)CBF (Doppler ultrasound) and CDO2 were quantified during the trials. IHX provoked similar reductions in S a O 2 and P a O 2 , while MAP was not affected by oxygen desaturation or KATP blockade. A smaller increase in ICABF (ΔBGB: 36 ± 23 vs. ΔAGB 11 ± 18%, p = 0.019) but not in VABF (∆BGB 26 ± 21 vs. ∆AGB 27 ± 27%, p = 0.893) was observed during the hypoxic trial under KATP channels blockade. Thus, IHX-induced increases in tCBF (∆BGB 32 ± 19 vs. ∆AGB 14 ± 13%, p = 0.012) and CDO2 relative changes (∆BGB 7 ± 13 vs. ∆AGB -6 ± 14%, p = 0.048) were attenuated during the AGB hypoxic trial. In a separate protocol, 6 healthy men (5 from protocol 1) underwent a 5-min exposure to normoxia and IHX before and 3 h after placebo (5 mg of cornstarch) ingestion. IHX reduced S a O 2 and P a O 2 , but placebo did not affect the ICABF, VABF, tCBF, or CDO2 responses. Therefore, in humans, KATP channels activation modulates vascular tone in the anterior rather than the posterior circulation of the brain, contributing to tCBF and CDO2 responses to hypoxia.
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Affiliation(s)
- Marcos P Rocha
- Laboratory of Exercise Sciences, Department of Physiology and Pharmacology, Fluminense Federal University, RJ, Brazil
| | - Monique O Campos
- Laboratory of Exercise Sciences, Department of Physiology and Pharmacology, Fluminense Federal University, RJ, Brazil
| | - João D Mattos
- Laboratory of Exercise Sciences, Department of Physiology and Pharmacology, Fluminense Federal University, RJ, Brazil
| | - Daniel E Mansur
- Laboratory of Exercise Sciences, Department of Physiology and Pharmacology, Fluminense Federal University, RJ, Brazil
| | - Helena N M Rocha
- Laboratory of Exercise Sciences, Department of Physiology and Pharmacology, Fluminense Federal University, RJ, Brazil
| | - Niels H Secher
- Department of Anaesthesia, The Copenhagen Muscle Research Centre, Rigshospitalet, University of Copenhagen, Denmark
| | - Antonio C L Nóbrega
- Laboratory of Exercise Sciences, Department of Physiology and Pharmacology, Fluminense Federal University, RJ, Brazil
| | - Igor A Fernandes
- NeuroV̇ASQ̇-Integrative Physiology Laboratory, Faculty of Physical Education, University of Brasília, Brazil
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23
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Mutch WAC, El-Gabalawy R, Ryner L, Puig J, Essig M, Kilborn K, Fidler K, Graham MR. Brain BOLD MRI O 2 and CO 2 stress testing: implications for perioperative neurocognitive disorder following surgery. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2020; 24:76. [PMID: 32131878 PMCID: PMC7057494 DOI: 10.1186/s13054-020-2800-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Accepted: 02/18/2020] [Indexed: 12/17/2022]
Abstract
Background Mechanical ventilation to alter and improve respiratory gases is a fundamental feature of critical care and intraoperative anesthesia management. The range of inspired O2 and expired CO2 during patient management can significantly deviate from values in the healthy awake state. It has long been appreciated that hyperoxia can have deleterious effects on organs, especially the lung and retina. Recent work shows intraoperative end-tidal (ET) CO2 management influences the incidence of perioperative neurocognitive disorder (POND). The interaction of O2 and CO2 on cerebral blood flow (CBF) and oxygenation with alterations common in the critical care and operating room environments has not been well studied. Methods We examine the effects of controlled alterations in both ET O2 and CO2 on cerebral blood flow (CBF) in awake adults using blood oxygenation level-dependent (BOLD) and pseudo-continuous arterial spin labeling (pCASL) MRI. Twelve healthy adults had BOLD and CBF responses measured to alterations in ET CO2 and O2 in various combinations commonly observed during anesthesia. Results Dynamic alterations in regional BOLD and CBF were seen in all subjects with expected and inverse brain voxel responses to both stimuli. These effects were incremental and rapid (within seconds). The most dramatic effects were seen with combined hyperoxia and hypocapnia. Inverse responses increased with age suggesting greater risk. Conclusions Human CBF responds dramatically to alterations in ET gas tensions commonly seen during anesthesia and in critical care. Such alterations may contribute to delirium following surgery and under certain circumstances in the critical care environment. Trial registration ClincialTrials.gov NCT02126215 for some components of the study. First registered April 29, 2014.
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Affiliation(s)
- W Alan C Mutch
- Department of Anesthesiology, Perioperative and Pain Medicine, Max Rady College of Medicine, University of Manitoba, 2nd Floor, Harry Medovy House, 671 William Ave., Winnipeg, MB, R3E 0Z2, Canada. .,Canada North Concussion Network, .
| | - Renée El-Gabalawy
- Department of Anesthesiology, Perioperative and Pain Medicine, Max Rady College of Medicine, University of Manitoba, 2nd Floor, Harry Medovy House, 671 William Ave., Winnipeg, MB, R3E 0Z2, Canada.,Department of Clinical Health Psychology, University of Manitoba, Winnipeg, Canada
| | - Lawrence Ryner
- Canada North Concussion Network.,Department of Radiology, University of Manitoba, Winnipeg, Canada.,Department of Physics, University of Manitoba, Winnipeg, Canada
| | - Josep Puig
- Department of Radiology, University of Manitoba, Winnipeg, Canada
| | - Marco Essig
- Canada North Concussion Network.,Department of Radiology, University of Manitoba, Winnipeg, Canada
| | - Kayla Kilborn
- Department of Anesthesiology, Perioperative and Pain Medicine, Max Rady College of Medicine, University of Manitoba, 2nd Floor, Harry Medovy House, 671 William Ave., Winnipeg, MB, R3E 0Z2, Canada
| | - Kelsi Fidler
- Department of Anesthesiology, Perioperative and Pain Medicine, Max Rady College of Medicine, University of Manitoba, 2nd Floor, Harry Medovy House, 671 William Ave., Winnipeg, MB, R3E 0Z2, Canada
| | - M Ruth Graham
- Department of Anesthesiology, Perioperative and Pain Medicine, Max Rady College of Medicine, University of Manitoba, 2nd Floor, Harry Medovy House, 671 William Ave., Winnipeg, MB, R3E 0Z2, Canada.,Canada North Concussion Network
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24
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Abstract
PURPOSE OF REVIEW The topic of perioperative hyperoxia remains controversial, with valid arguments on both the 'pro' and 'con' side. On the 'pro' side, the prevention of surgical site infections was a strong argument, leading to the recommendation of the use of hyperoxia in the guidelines of the Center for Disease Control and the WHO. On the 'con' side, the pathophysiology of hyperoxia has increasingly been acknowledged, in particular the pulmonary side effects and aggravation of ischaemia/reperfusion injuries. RECENT FINDINGS Some 'pro' articles leading to the Center for Disease Control and WHO guidelines advocating perioperative hyperoxia have been retracted, and the recommendations were downgraded from 'strong' to 'conditional'. At the same time, evidence that supports a tailored, more restrictive use of oxygen, for example, in patients with myocardial infarction or following cardiac arrest, is accumulating. SUMMARY The change in recommendation exemplifies that despite much work performed on the field of hyperoxia recently, evidence on either side of the argument remains weak. Outcome-based research is needed for reaching a definite recommendation.
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25
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Mattos JD, Campos MO, Rocha MP, Mansur DE, Rocha HNM, Garcia VP, Rocha NG, Alvares TS, Secher NH, Nóbrega ACL, Fernandes IA. Differential vasomotor responses to isocapnic hyperoxia: cerebral versus peripheral circulation. Am J Physiol Regul Integr Comp Physiol 2020; 318:R182-R187. [DOI: 10.1152/ajpregu.00248.2019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Isocapnic hyperoxia (IH) evokes cerebral and peripheral hypoperfusion via both disturbance of redox homeostasis and reduction in nitric oxide (NO) bioavailability. However, it is not clear whether the magnitude of the vasomotor responses depends on the vessel network exposed to IH. To test the hypothesis that the magnitude of IH-induced reduction in peripheral blood flow (BF) may differ from the hypoperfusion response observed in the cerebral vascular network under oxygen-enriched conditions, nine healthy men (25 ± 3 yr, mean ± SD) underwent 10 min of IH during either saline or vitamin C (3 g) infusion, separately. Femoral artery (FA), internal carotid artery (ICA), and vertebral artery (VA) BF (Doppler ultrasound), as well as arterial oxidant (8-isoprostane), antioxidant [ascorbic acid (AA)], and NO bioavailability (nitrite) markers were simultaneously measured. IH increased 8-isoprostane levels and reduced nitrite levels; these responses were followed by a reduction in both FA BF and ICA BF, whereas VA BF did not change. Absolute and relative reductions in FA BF were greater than IH-induced changes in ICA and VA perfusion. Vitamin C infusion increased arterial AA levels and abolished the IH-induced increase in 8-isoprostane levels and reduction in nitrite levels. Whereas ICA and VA BF did not change during the vitamin C-IH trial, FA perfusion increased and reached similar levels to those observed during normoxia with saline infusion. Therefore, the magnitude of IH-induced reduction in femoral blood flow is greater than that observed in the vessel network of the brain, which might involve the determinant contribution that NO has in the regulation of peripheral vascular perfusion.
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Affiliation(s)
- João D. Mattos
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, Brazil
| | - Monique O. Campos
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, Brazil
| | - Marcos P. Rocha
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, Brazil
| | - Daniel E. Mansur
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, Brazil
| | - Helena N. M. Rocha
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, Brazil
| | - Vinicius P. Garcia
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, Brazil
| | - Natalia G. Rocha
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, Brazil
| | - Thiago S. Alvares
- Nutrition Institute, Federal University of Rio de Janeiro, Macaé, Brazil
| | - Niels H. Secher
- Department of Anesthesia, The Copenhagen Muscle Research Centre, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | | | - Igor A. Fernandes
- NeuroV̇ASQ̇-Integrative Physiology Laboratory, Faculty of Physical Education, University of Brasília, Brasília, Brazil
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26
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Fukuda S, Koga Y, Fujita M, Suehiro E, Kaneda K, Oda Y, Ishihara H, Suzuki M, Tsuruta R. Hyperoxemia during the hyperacute phase of aneurysmal subarachnoid hemorrhage is associated with delayed cerebral ischemia and poor outcome: a retrospective observational study. J Neurosurg 2019; 134:25-32. [PMID: 31731268 DOI: 10.3171/2019.9.jns19781] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Accepted: 09/11/2019] [Indexed: 11/06/2022]
Abstract
OBJECTIVE The harmful effects of hyperoxemia have been reported in critically ill patients with various disorders, including those with brain injuries. However, the effect of hyperoxemia on aneurysmal subarachnoid hemorrhage (aSAH) patients is unclear. In this study the authors aimed to determine whether hyperoxemia during the hyperacute or acute phase in patients with aSAH is associated with delayed cerebral ischemia (DCI) and poor neurological outcome. METHODS In this single-center retrospective study, data from patients with aSAH treated between January 2011 and June 2017 were reviewed. The patients were classified into groups according to whether they experienced DCI (DCI group and non-DCI group) and whether they had a poor outcome at discharge (poor outcome group and favorable outcome group). The background characteristics and time-weighted average (TWA) PaO2 during the first 24 hours after arrival at the treatment facility (TWA24h-PaO2) and between the first 24 hours after arrival and day 6 (TWA6d-PaO2), the hyperacute and acute phases, respectively, were compared between the groups. Factors related to DCI and poor outcome were evaluated with logistic regression analyses. RESULTS Of 197 patients with aSAH, 42 patients experienced DCI and 82 patients had a poor outcome at discharge. TWA24h-PaO2 was significantly higher in the DCI group than in the non-DCI group (186 [141-213] vs 161 [138-192] mm Hg, p = 0.029) and in the poor outcome group than in the favorable outcome group (176 [154-205] vs 156 [136-188] mm Hg, p = 0.004). TWA6d-PaO2 did not differ significantly between the groups. Logistic regression analyses revealed that higher TWA24h-PaO2 was an independent risk factor for DCI (OR 1.09, 95% CI 1.01-1.17, p = 0.037) and poor outcome (OR 1.17, 95% CI 1.06-1.29, p = 0.002). CONCLUSIONS Hyperoxemia during the first 24 hours was associated with DCI and a poor outcome in patients with aSAH. Excessive oxygen therapy might have an adverse effect in the hyperacute phase of aSAH.
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Affiliation(s)
- Shinya Fukuda
- 1Advanced Medical Emergency and Critical Care Center, Yamaguchi University Hospital, Ube, Yamaguchi; and
| | - Yasutaka Koga
- 1Advanced Medical Emergency and Critical Care Center, Yamaguchi University Hospital, Ube, Yamaguchi; and
| | | | - Eiichi Suehiro
- 1Advanced Medical Emergency and Critical Care Center, Yamaguchi University Hospital, Ube, Yamaguchi; and
- 3Department of Neurosurgery, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi, Japan
| | - Kotaro Kaneda
- 1Advanced Medical Emergency and Critical Care Center, Yamaguchi University Hospital, Ube, Yamaguchi; and
| | | | - Hideyuki Ishihara
- 3Department of Neurosurgery, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi, Japan
| | - Michiyasu Suzuki
- 3Department of Neurosurgery, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi, Japan
| | - Ryosuke Tsuruta
- 1Advanced Medical Emergency and Critical Care Center, Yamaguchi University Hospital, Ube, Yamaguchi; and
- 2Acute and General Medicine and
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27
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Campos MO, Mansur DE, Mattos JD, Paiva ACS, Videira RLR, Macefield VG, da Nóbrega ACL, Fernandes IA. Acid-sensing ion channels blockade attenuates pressor and sympathetic responses to skeletal muscle metaboreflex activation in humans. J Appl Physiol (1985) 2019; 127:1491-1501. [PMID: 31545154 DOI: 10.1152/japplphysiol.00401.2019] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
In animals, the blockade of acid-sensing ion channels (ASICs), cation pore-forming membrane proteins located in the free nerve endings of group IV afferent fibers, attenuates increases in arterial pressure (AP) and sympathetic nerve activity (SNA) during muscle contraction. Therefore, ASICs play a role in mediating the metabolic component (skeletal muscle metaboreflex) of the exercise pressor reflex in animal models. Here we tested the hypothesis that ASICs also play a role in evoking the skeletal muscle metaboreflex in humans, quantifying beat-by-beat mean AP (MAP; finger photoplethysmography) and muscle SNA (MSNA; microneurography) in 11 men at rest and during static handgrip exercise (SHG; 35% of the maximal voluntary contraction) and postexercise muscle ischemia (PEMI) before (B) and after (A) local venous infusion of either saline or amiloride (AM), an ASIC antagonist, via the Bier block technique. MAP (BAM +30 ± 6 vs. AAM +25 ± 7 mmHg, P = 0.001) and MSNA (BAM +14 ± 9 vs. AAM +10 ± 6 bursts/min, P = 0.004) responses to SHG were attenuated under ASIC blockade. Amiloride also attenuated the PEMI-induced increases in MAP (BAM +25 ± 6 vs. AAM +16 ± 6 mmHg, P = 0.0001) and MSNA (BAM +16 ± 9 vs. AAM +8 ± 8 bursts/min, P = 0.0001). MAP and MSNA responses to SHG and PEMI were similar before and after saline infusion. We conclude that ASICs play a role in evoking pressor and sympathetic responses to SHG and the isolated activation of the skeletal muscle metaboreflex in humans. NEW & NOTEWORTHY We showed that regional blockade of the acid-sensing ion channels (ASICs), induced by venous infusion of the antagonist amiloride via the Bier block anesthetic technique, attenuated increases in arterial pressure and muscle sympathetic nerve activity during both static handgrip exercise and postexercise muscle ischemia. These findings indicate that ASICs contribute to both pressor and sympathetic responses to the activation of the skeletal muscle metaboreflex in humans.
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Affiliation(s)
- Monique O Campos
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, Brazil
| | - Daniel E Mansur
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, Brazil
| | - João D Mattos
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, Brazil
| | - Adrielle C S Paiva
- Laboratory of Exercise Sciences, Fluminense Federal University, Niterói, Brazil
| | | | - Vaughan G Macefield
- School of Medicine, Western Sydney University, Sydney, Australia.,Baker Heart and Diabetes Institute, Melbourne, Australia
| | | | - Igor A Fernandes
- NeuroV̇ASQ̇-Integrative Physiology Laboratory, Faculty of Physical Education, University of Brasília, Brasília, Brazil
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28
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Bailey DM. Oxygen is rocket fuel for the human brain; a radical perspective! J Physiol 2018; 597:659-660. [PMID: 30488438 DOI: 10.1113/jp277475] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Damian Miles Bailey
- Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, Wales, UK
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