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Wang SY, Gao J, Zhao JH. Effects of high altitude on renal physiology and kidney diseases. Front Physiol 2022; 13:969456. [PMID: 36338473 PMCID: PMC9630589 DOI: 10.3389/fphys.2022.969456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Accepted: 10/10/2022] [Indexed: 11/13/2022] Open
Abstract
The hypobaric and hypoxic conditions of high-altitude areas exert adverse effects on the respiratory, circulatory and nervous systems. The kidneys have an abundant blood supply (20%–25% of cardiac output) and high blood flow; thus, they are susceptible to the effects of hypoxia. However, the effects of acute and chronic exposure to high altitudes on renal physiology and pathology are not fully understood. Moreover, few studies have investigated the impact of high-altitude exposure on patients with chronic kidney disease or acute kidney injury. In this review, we summarized changes in renal physiology and renal pathology due to high-altitude exposure as well as the impact of high-altitude exposure on existing kidney diseases, with the aim of informing the prevention and treatment of kidney diseases at high altitudes.
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Affiliation(s)
- Si-Yang Wang
- 953th Hospital, Shigatse Branch, Xinqiao Hospital, Army Medical University (Third Military Medical University), Chongqing, China
| | - Jie Gao
- Department of Nephrology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, Shandong, China
| | - Jing-Hong Zhao
- Department of Nephrology, The Key Laboratory for the Prevention and Treatment of Chronic Kidney Disease of Chongqing, Chongqing Clinical Research Center of Kidney and Urology Diseases, Xinqiao Hospital, Army Medical University (Third Military Medical University), Chongqing, China
- *Correspondence: Jing-Hong Zhao,
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2
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Wearing OH, Scott GR. Evolved reductions in body temperature and the metabolic costs of thermoregulation in deer mice native to high altitude. Proc Biol Sci 2022; 289:20221553. [PMID: 36168757 PMCID: PMC9515628 DOI: 10.1098/rspb.2022.1553] [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: 08/08/2022] [Accepted: 08/30/2022] [Indexed: 11/12/2022] Open
Abstract
The evolution of endothermy was instrumental to the diversification of birds and mammals, but the energetic demands of maintaining high body temperature could offset the advantages of endothermy in some environments. We hypothesized that reductions in body temperature help high-altitude natives overcome the metabolic challenges of cold and hypoxia in their native environment. Deer mice (Peromyscus maniculatus) from high-altitude and low-altitude populations were bred in captivity to the second generation and were acclimated as adults to warm normoxia or cold hypoxia. Subcutaneous temperature (Tsub, used as a proxy for body temperature) and cardiovascular function were then measured throughout the diel cycle using biotelemetry. Cold hypoxia increased metabolic demands, as reflected by increased food consumption and heart rate (associated with reduced vagal tone). These increased metabolic demands were offset by plastic reductions in Tsub (approx. 2°C) in response to cold hypoxia, and highlanders had lower Tsub (approx. 1°C) than lowlanders in both environmental treatments. Empirical and theoretical evidence suggested that these reductions could together reduce metabolic demands by approximately 10-30%. Therefore, plastic and evolved reductions in body temperature can help mammals overcome the metabolic challenges at high altitude and may be a valuable energy-saving strategy in some non-hibernating endotherms in extreme environments.
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Affiliation(s)
- Oliver H. Wearing
- Department of Biology, McMaster University, Life Sciences Building, 1280 Main Street W, Hamilton, ON, Canada L8S 4K1
| | - Graham R. Scott
- Department of Biology, McMaster University, Life Sciences Building, 1280 Main Street W, Hamilton, ON, Canada L8S 4K1
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3
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Oyedokun PA, Akhigbe RE, Ajayi LO, Ajayi AF. Impact of hypoxia on male reproductive functions. Mol Cell Biochem 2022; 478:875-885. [PMID: 36107286 DOI: 10.1007/s11010-022-04559-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Accepted: 09/02/2022] [Indexed: 11/30/2022]
Abstract
Male reproductive functions, which include testicular steroidogenesis, spermatogenesis, and sexual/erectile functions are key in male fertility, but may be adversely altered by several factors, including hypoxia. This review demonstrates the impact of hypoxia on male reproductive functions. Acute exposure to hypoxia promotes testosterone production via stimulation of autophagy and upregulation of steroidogenic enzymes and voltage-gated L-type calcium channel, nonetheless, chronic exposure to hypoxia impairs steroidogenesis via suppression of the hypothalamic-pituitary-testicular axis. Also, hypoxia distorts spermatogenesis and reduces sperm count, motility, and normal forms via upregulation of VEGF and oxidative stress-sensitive signaling. Furthermore, hypoxia induces sexual and erectile dysfunction via a testosterone-dependent downregulation of NO/cGMP signaling and upregulation of PGE1/TGFβ1-driven penile endothelial dysfunction. Notably, hypoxia programs male sexual function and spermatogenesis/sperm quality via feminization and demasculinization of males and oxidative stress-mediated alteration in sperm DNA methylation. Since oxidative stress plays a central role in hypoxia-induced male reproductive dysfunction, studies exploring the effects of antioxidants and upregulation of transcription of antioxidants on hypoxia-induced male reproductive dysfunction are recommended.
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Affiliation(s)
- P A Oyedokun
- Anchor Reproductive Physiology and Bioinformatics Research Unit, Department of Physiology, Ladoke Akintola University of Technology, Ogbomoso, Oyo, Nigeria
| | - R E Akhigbe
- Anchor Reproductive Physiology and Bioinformatics Research Unit, Department of Physiology, Ladoke Akintola University of Technology, Ogbomoso, Oyo, Nigeria.
- Reproductive Biology and Toxicology Research Laboratory, Oasis of Grace Hospital, Osogbo, Osun, Nigeria.
| | - L O Ajayi
- Department of Biochemistry, Ladoke Akintola University of Technology, Ogbomoso, Oyo, Nigeria
| | - A F Ajayi
- Anchor Reproductive Physiology and Bioinformatics Research Unit, Department of Physiology, Ladoke Akintola University of Technology, Ogbomoso, Oyo, Nigeria
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Zhang M, Cheng Y, Zhai Y, Cui Y, Zhang W, Sun H, Xin W, Zhou L, Gao X, Li S, Sun H. Attenuated succinate accumulation relieves neuronal injury induced by hypoxia in neonatal mice. Cell Death Dis 2022; 8:138. [PMID: 35351859 PMCID: PMC8964675 DOI: 10.1038/s41420-022-00940-7] [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: 10/21/2021] [Revised: 02/19/2022] [Accepted: 03/08/2022] [Indexed: 12/01/2022]
Abstract
Hypoxia causes neonatal neuronal damage. However, the underlying mechanism remains unclear. This study aimed to explore the changes in succinate levels and identify the mechanisms underlying their contribution to hypoxia-induced damage in newborn mice. The neonatal C57BL/6J mouse hypoxia model was used in our study. We evaluated the levels of succinate, iron, reactive oxygen species (ROS), and mitochondrial ROS, and assessed mitophagy, neuronal damage, and learning and memory function, after hypoxia treatment. The neonatal mice showed increased succinate levels in the early hypoxia stage, followed by increased levels of oxidative stress, iron stress, neuronal damage, and cognitive deficits. Succinate levels were significantly reduced following treatment with inhibitors of succinate dehydrogenase (SDH), purine nucleotide cycle (PNC), and malate/aspartate shuttle (MAS), with the corresponding attenuation of oxidative stress, iron stress, neuronal damage, and cognitive impairment. Reversal catalysis of SDH through fumarate from the PNC and MAS pathways might be involved in hypoxia-induced succinate accumulation. Succinate accumulation in the early period after hypoxia may crucially contribute to oxidative and iron stress. Relieving succinate accumulation at the early hypoxia stage could prevent neuronal damage and cognitive impairment in neonatal hypoxia. ![]()
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The influence of short-term high-altitude acclimatization on cerebral and leg tissue oxygenation post-orthostasis. Eur J Appl Physiol 2021; 121:3095-3102. [PMID: 34319446 DOI: 10.1007/s00421-021-04765-7] [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: 01/11/2021] [Accepted: 07/06/2021] [Indexed: 10/20/2022]
Abstract
PURPOSE Orthostasis at sea level decreases brain tissue oxygenation and increases risk of syncope. High altitude reduces brain and peripheral muscle tissue oxygenation. This study determined the effect of short-term altitude acclimatization on cerebral and peripheral leg tissue oxygenation index (TOI) post-orthostasis. METHOD Seven lowlanders completed a supine-to-stand maneuver at sea level (450 m) and for 3 consecutive days at high altitude (3776 m). Cardiorespiratory measurements and near-infrared spectroscopy-derived oxygenation of the frontal lobe (cerebral TOI) and vastus lateralis (leg TOI) were measured at supine and 5-min post-orthostasis. RESULTS After orthostasis at sea level, cerebral TOI decreased [mean Δ% (95% confidential interval): - 4.5%, (- 7.5, - 1.5), P < 0.001], whilst leg TOI was unchanged [- 4.6%, (- 10.9, 1.7), P = 0.42]. High altitude had no effect on cerebral TOI following orthostasis [days 1-3: - 2.3%, (- 5.3, 0.7); - 2.4%, (- 5.4, 0.6); - 2.1%, (- 5.1, 0.9), respectively, all P > 0.05], whereas leg TOI decreased [days 1-3: - 12.0%, (- 18.3, - 5.7); - 12.1%, (- 18.4, - 5.8); - 10.2%, (- 16.5, - 3.9), respectively, all P < 0.001]. This response did not differ with days spent at high altitude, despite evidence of cardiorespiratory acclimatization [increased peripheral oxygen saturation (supine: P = 0.01; stand: P = 0.02) and decreased end-tidal carbon dioxide (supine: P = 0.003; stand: P = 0.01)]. CONCLUSION Cerebral oxygenation is preferentially maintained over leg oxygenation post-orthostasis at high altitude, suggesting different vascular regulation between cerebral and peripheral circulations. Short-term acclimatization to high altitude did not alter cerebral and leg oxygenation responses to orthostasis.
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Keramidas ME, Kölegård R, Eiken O. Hypoxia gradually augments metabolic and thermoperceptual responsiveness to repeated whole-body cold stress in humans. Exp Physiol 2020; 105:2123-2140. [PMID: 33140429 PMCID: PMC7756580 DOI: 10.1113/ep089070] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2020] [Accepted: 10/30/2020] [Indexed: 12/02/2022]
Abstract
New Findings What is the central question of this study? In male lowlanders, does hypoxia modulate thermoregulatory effector responses during repeated whole‐body cold stress encountered in a single day? What is the main finding and its importance? A ∼10 h sustained exposure to hypoxia appears to mediate a gradual upregulation of endogenous heat production, preventing the progressive hypothermic response prompted by serial cold stimuli. Also, hypoxia progressively degrades mood, and compounds the perceived thermal discomfort, and sensations of fatigue and coldness.
Abstract We examined whether hypoxia would modulate thermoeffector responses during repeated cold stress encountered in a single day. Eleven men completed two ∼10 h sessions, while breathing, in normobaria, either normoxia or hypoxia (PO2: 12 kPa). During each session, subjects underwent sequentially three 120 min immersions to the chest in 20°C water (CWI), interspersed by 120 min rewarming. In normoxia, the final drop in rectal temperature (Trec) was greater in the third (∼1.2°C) than in the first and second (∼0.9°C) CWIs (P < 0.05). The first hypoxic CWI augmented the Trec fall (∼1.2°C; P = 0.002), but the drop in Trec did not vary between the three hypoxic CWIs (P = 0.99). In normoxia, the metabolic heat production (M˙) was greater during the first half of the third CWI than during the corresponding part of the first CWI (P = 0.02); yet the difference was blunted during the second half of the CWIs (P = 0.89). In hypoxia, by contrast, the increase in M˙ was augmented by ∼25% throughout the third CWI (P < 0.01). Regardless of the breathing condition, the cold‐induced elevation in mean arterial pressure was blunted in the second and third CWI (P < 0.05). Hypoxia aggravated the sensation of coldness (P = 0.05) and thermal discomfort (P = 0.04) during the second half of the third CWI. The present findings therefore demonstrate that prolonged hypoxia mediates, in a gradual manner, metabolic and thermoperceptual sensitization to repeated cold stress.
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Affiliation(s)
- Michail E Keramidas
- Division of Environmental Physiology, Swedish Aerospace Physiology Center, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Roger Kölegård
- Division of Environmental Physiology, Swedish Aerospace Physiology Center, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Ola Eiken
- Division of Environmental Physiology, Swedish Aerospace Physiology Center, KTH Royal Institute of Technology, Stockholm, Sweden
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Vinueza Veloz AF, Yaulema Riss AK, De Zeeuw CI, Carpio Arias TV, Vinueza Veloz MF. Blood Pressure in Andean Adults Living Permanently at Different Altitudes. High Alt Med Biol 2020; 21:360-369. [PMID: 32845744 DOI: 10.1089/ham.2019.0101] [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] [Indexed: 12/15/2022] Open
Abstract
Vinueza Veloz, Andrés Fernando, Aymaru Kailli Yaulema Riss, Chris I. De Zeeuw, Tannia Valeria Carpio Arias, and María Fernanda Vinueza Veloz. Blood pressure in Andean adults living permanently at different altitudes. High Alt Med Biol. 21:360-369, 2020. Aims: To estimate the association between blood pressure (BP) and chronic exposure to altitude in nonhypertensive Andean adults, while taking ethnicity into consideration. Materials and Methods: Sample included 10,041 nonhypertensive adults with indigenous or mixed ethnic background (the latter also referred to as mestizos), who permanently lived at different altitudes. BP was measured following international recommendations. Altitude was measured in meters above the sea level (masl) using a global positioning system. Data were analyzed through linear regression models with restricted cubic splines. Results: A significant nonlinear relation between altitude and systolic blood pressure (SBP) as well as diastolic blood pressure (DBP) was found (both p < 0.001). BP described a j-shaped curve, where the minimum was observed between 750 and 1250 masl, from where both SBP and DBP rose as altitude increased. These associations were independent from sex, age, index of economic wellbeing, body mass index, and years of education. Interestingly, at all altitudes indigenous people had lower SBP and DBP in comparison to mestizos (both p < 0.001). Conclusions: Living permanently at altitudes ≥750 masl is associated with higher SBP and DBP in Andean dwellers and this association is modulated by their ethnic background.
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Affiliation(s)
- Andrés Fernando Vinueza Veloz
- Chapintza Health Center, Ministerio de Salud Pública del Ecuador, Chapintza, Ecuador.,Abteilung Gastroenterologie und Diabetologie, Gemeinschaftskrankenhaus Havelhöhe, Berlin, Germany
| | - Aymaru Kailli Yaulema Riss
- Chapintza Health Center, Ministerio de Salud Pública del Ecuador, Chapintza, Ecuador.,Abteilung Gastroenterologie und Diabetologie, Gemeinschaftskrankenhaus Havelhöhe, Berlin, Germany
| | - Chris I De Zeeuw
- Department of Neuroscience, Erasmus MC, Rotterdam, The Netherlands.,Netherlands Institute for Neuroscience, Royal Academy of Arts and Sciences, Amsterdam, The Netherlands
| | - Tannia Valeria Carpio Arias
- Research Group GIANH, School of Nutrition and Dietetics, Faculty of Public Health, Escuela Superior Politécnica de Chimborazo, Riobamba, Ecuador
| | - María Fernanda Vinueza Veloz
- Department of Neuroscience, Erasmus MC, Rotterdam, The Netherlands.,School of Medicine, Faculty of Public Health, Escuela Superior Politécnica de Chimborazo, Riobamba, Ecuador
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8
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Palubiski LM, O'Halloran KD, O'Neill J. Renal Physiological Adaptation to High Altitude: A Systematic Review. Front Physiol 2020; 11:756. [PMID: 32765289 PMCID: PMC7378794 DOI: 10.3389/fphys.2020.00756] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Accepted: 06/11/2020] [Indexed: 11/15/2022] Open
Abstract
Background: Under normal physiological conditions, renal tissue oxygen is tightly regulated. At high altitude, a physiological challenge is imposed by the decrease in atmospheric oxygen. At the level of the kidney, the physiological adaptation to high altitude is poorly understood, which might relate to different integrated responses to hypoxia over different time domains of exposure. Thus, this systematic review sought to examine the renal physiological adaptation to high altitude in the context of the magnitude and duration of exposure to high altitude in the healthy kidney model. Methods: To conduct the review, three electronic databases were examined: OVID, PubMed, and Scopus. Search terms included: Altitude, renal, and kidney. The broad, but comprehensive search, retrieved 1,057 articles published between 1997 and April 2020. Fourteen studies were included in the review. Results: The inconsistent effect of high altitude on renal hemodynamic parameters (glomerular filtration rate, renal blood flow, and renal plasma flow), electrolyte balance, and renal tissue oxygen is difficult to interpret; however, the data suggest that the nature and extent of renal physiological adaptation at high altitude appears to be related to the magnitude and duration of the exposure. Conclusion: It is clear that renal physiological adaptation to high altitude is a complex process that is not yet fully understood. Further research is needed to better understand the renal physiological adaptation to hypoxia and how renal oxygen homeostasis and metabolism is defended during exposure to high altitude and affected as a long-term consequence of renal adaptation at high altitude.
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Affiliation(s)
- Lisa M Palubiski
- Department of Physiology, School of Medicine, College of Medicine & Health, University College Cork, Cork, Ireland
| | - Ken D O'Halloran
- Department of Physiology, School of Medicine, College of Medicine & Health, University College Cork, Cork, Ireland
| | - Julie O'Neill
- Department of Physiology, School of Medicine, College of Medicine & Health, University College Cork, Cork, Ireland
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Niebauer JH, Niebauer J, Wille M, Burtscher M. Systemic Blood Pressure Variation During a 12-Hour Exposure to Normobaric Hypoxia (4500 m). High Alt Med Biol 2020; 21:194-199. [PMID: 32186921 DOI: 10.1089/ham.2019.0130] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
This study was aimed at evaluating a potential association between blood pressure variation and acute mountain sickness (AMS) during acute exposure to normobaric hypoxia. A total of 77 healthy subjects (43 males, 34 females) were exposed to a simulated altitude of 4500 m for 12 hours. Peripheral oxygen saturation, heart rate, systemic blood pressure, and Lake Louise AMS scores were recorded before and during (30 minutes, 3, 6, 9, and 12 hours) hypoxic exposure. Blood pressure dips were observed at 3-hour mark. However, systolic blood pressure fell more pronounced from baseline during the initial 30 minutes in normobaric hypoxia (-17.5 vs. -11.0 mmHg, p = 0.01) in subjects suffering from AMS (AMS+; n = 56) than in those remaining unaffected from AMS (AMS-; n = 21); values did not differ between groups over the subsequent time course. Our data may suggest a transient autonomic dysfunction resulting in a more pronounced blood pressure drop during initial hypoxic exposure in AMS+ compared with AMS- subjects.
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Affiliation(s)
| | - Josef Niebauer
- University Institute of Sports Medicine, Prevention and Rehabilitation, Paracelsus Medical University Salzburg, Salzburg, Austria
| | - Maria Wille
- Department of Sports Science, University of Innsbruck, Innsbruck, Austria
| | - Martin Burtscher
- Department of Sports Science, University of Innsbruck, Innsbruck, Austria.,Austrian Society for Alpine- and High-Altitude Medicine, Innsbruck, Austria
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Wang Q, Miao P, Modi HR, Garikapati S, Koehler RC, Thakor NV. Therapeutic hypothermia promotes cerebral blood flow recovery and brain homeostasis after resuscitation from cardiac arrest in a rat model. J Cereb Blood Flow Metab 2019; 39:1961-1973. [PMID: 29739265 PMCID: PMC6775582 DOI: 10.1177/0271678x18773702] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Laboratory and clinical studies have demonstrated that therapeutic hypothermia (TH), when applied as soon as possible after resuscitation from cardiac arrest (CA), results in better neurological outcome. This study tested the hypothesis that TH would promote cerebral blood flow (CBF) restoration and its maintenance after return of spontaneous circulation (ROSC) from CA. Twelve Wistar rats resuscitated from 7-min asphyxial CA were randomized into two groups: hypothermia group (7 H, n = 6), treated with mild TH (33-34℃) immediately after ROSC and normothermia group (7 N, n = 6,37.0 ± 0.5℃). Multiple parameters including mean arterial pressure, CBF, electroencephalogram (EEG) were recorded. The neurological outcomes were evaluated using electrophysiological (information quantity, IQ, of EEG) methods and a comprehensive behavior examination (neurological deficit score, NDS). TH consistently promoted better CBF restoration approaching the baseline levels in the 7 H group as compared with the 7 N group. CBF during the first 5-30 min post ROSC of the two groups was 7 H:90.5% ± 3.4% versus 7 N:76.7% ± 3.5% (P < 0.01). Subjects in the 7 H group showed significantly better IQ scores after ROSC and better NDS scores at 4 and 24 h. Early application of TH facilitates restoration of CBF back to baseline levels after CA, which in turn results in the restoration of brain electrical activity and improved neurological outcome.
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Affiliation(s)
- Qihong Wang
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Peng Miao
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA.,Institute of Biomedical Engineering, School of Communication and Information Engineering, Shanghai University, Shanghai, China
| | - Hiren R Modi
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Sahithi Garikapati
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Raymond C Koehler
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Nitish V Thakor
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA.,Department of Neurology, Johns Hopkins University, Baltimore, MD, USA.,Singapore Institute for Neurotechnology (SINAPSE), National University of Singapore, Singapore, Singapore
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Schwarz EI, Latshang TD, Furian M, Flück D, Segitz S, Müller-Mottet S, Ulrich S, Bloch KE, Kohler M. Blood pressure response to exposure to moderate altitude in patients with COPD. Int J Chron Obstruct Pulmon Dis 2019; 14:659-666. [PMID: 30936690 PMCID: PMC6421900 DOI: 10.2147/copd.s194426] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Purpose Patients with COPD might be particularly susceptible to hypoxia-induced autonomic dysregulation. Decreased baroreflex sensitivity (BRS) and increased blood pressure (BP) variability (BPV) are markers of impaired cardiovascular autonomic regulation and there is evidence for an association between decreased BRS/increased BPV and high cardiovascular risk. The aim of this study was to evaluate the effect of short-term exposure to moderate altitude on BP and measures of cardiovascular autonomic regulation in COPD patients. Materials and methods Continuous morning beat-to-beat BP was noninvasively measured with a Finometer® device for 10 minutes at low altitude (490 m, Zurich, Switzerland) and for 2 days at moderate altitude (2,590 m, Davos Jakobshorn, Switzerland) – the order of altitude exposure was randomized. Outcomes of interest were mean SBP and DBP, BPV expressed as the coefficient of variation (CV), and spontaneous BRS. Changes between low altitude and day 1 and day 2 at moderate altitude were assessed by ANOVA for repeated measurements with Fisher’s exact test analysis. Results Thirty-seven patients with moderate to severe COPD (mean±SD age 64±6 years, FEV1 60%±17%) were included. Morning SBP increased by +10.8 mmHg (95% CI: 4.7–17.0, P=0.001) and morning DBP by +5.0 mmHg (95% CI: 0.8–9.3, P=0.02) in response to altitude exposure. BRS significantly decreased (P=0.03), whereas BPV significantly and progressively increased (P<0.001) upon exposure to altitude. Conclusion Exposure of COPD patients to moderate altitude is associated with a clinically relevant increase in BP, which seems to be related to autonomic dysregulation. Clinical trial registration ClinicalTrials.gov (NCT01875133).
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Affiliation(s)
- Esther I Schwarz
- Department of Pulmonology and Sleep Disorders Centre, University Hospital of Zurich, Zurich, Switzerland,
| | - Tsogyal D Latshang
- Department of Pulmonology and Sleep Disorders Centre, University Hospital of Zurich, Zurich, Switzerland,
| | - Michael Furian
- Department of Pulmonology and Sleep Disorders Centre, University Hospital of Zurich, Zurich, Switzerland,
| | - Deborah Flück
- Department of Pulmonology and Sleep Disorders Centre, University Hospital of Zurich, Zurich, Switzerland,
| | - Sebastian Segitz
- Department of Pulmonology and Sleep Disorders Centre, University Hospital of Zurich, Zurich, Switzerland,
| | - Severine Müller-Mottet
- Department of Pulmonology and Sleep Disorders Centre, University Hospital of Zurich, Zurich, Switzerland,
| | - Silvia Ulrich
- Department of Pulmonology and Sleep Disorders Centre, University Hospital of Zurich, Zurich, Switzerland,
| | - Konrad E Bloch
- Department of Pulmonology and Sleep Disorders Centre, University Hospital of Zurich, Zurich, Switzerland, .,Centre for Integrative Human Physiology, University of Zurich, Zurich, Switzerland,
| | - Malcolm Kohler
- Department of Pulmonology and Sleep Disorders Centre, University Hospital of Zurich, Zurich, Switzerland, .,Centre for Integrative Human Physiology, University of Zurich, Zurich, Switzerland,
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Pathobiological mechanisms underlying metabolic syndrome (MetS) in chronic obstructive pulmonary disease (COPD): clinical significance and therapeutic strategies. Pharmacol Ther 2019; 198:160-188. [PMID: 30822464 PMCID: PMC7112632 DOI: 10.1016/j.pharmthera.2019.02.013] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Chronic obstructive pulmonary disease (COPD) is a major incurable global health burden and is currently the 4th largest cause of death in the world. Importantly, much of the disease burden and health care utilisation in COPD is associated with the management of its comorbidities (e.g. skeletal muscle wasting, ischemic heart disease, cognitive dysfunction) and infective viral and bacterial acute exacerbations (AECOPD). Current pharmacological treatments for COPD are relatively ineffective and the development of effective therapies has been severely hampered by the lack of understanding of the mechanisms and mediators underlying COPD. Since comorbidities have a tremendous impact on the prognosis and severity of COPD, the 2015 American Thoracic Society/European Respiratory Society (ATS/ERS) Research Statement on COPD urgently called for studies to elucidate the pathobiological mechanisms linking COPD to its comorbidities. It is now emerging that up to 50% of COPD patients have metabolic syndrome (MetS) as a comorbidity. It is currently not clear whether metabolic syndrome is an independent co-existing condition or a direct consequence of the progressive lung pathology in COPD patients. As MetS has important clinical implications on COPD outcomes, identification of disease mechanisms linking COPD to MetS is the key to effective therapy. In this comprehensive review, we discuss the potential mechanisms linking MetS to COPD and hence plausible therapeutic strategies to treat this debilitating comorbidity of COPD.
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Boehme J, Le Moan N, Kameny RJ, Loucks A, Johengen MJ, Lesneski AL, Gong W, Goudy BD, Davis T, Tanaka K, Davis A, He Y, Long-Boyle J, Ivaturi V, Gobburu JVS, Winger JA, Cary SP, Datar SA, Fineman JR, Krtolica A, Maltepe E. Preservation of myocardial contractility during acute hypoxia with OMX-CV, a novel oxygen delivery biotherapeutic. PLoS Biol 2018; 16:e2005924. [PMID: 30335746 PMCID: PMC6193608 DOI: 10.1371/journal.pbio.2005924] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Accepted: 09/13/2018] [Indexed: 01/05/2023] Open
Abstract
The heart exhibits the highest basal oxygen (O2) consumption per tissue mass of any organ in the body and is uniquely dependent on aerobic metabolism to sustain contractile function. During acute hypoxic states, the body responds with a compensatory increase in cardiac output that further increases myocardial O2 demand, predisposing the heart to ischemic stress and myocardial dysfunction. Here, we test the utility of a novel engineered protein derived from the heme-based nitric oxide (NO)/oxygen (H-NOX) family of bacterial proteins as an O2 delivery biotherapeutic (Omniox-cardiovascular [OMX-CV]) for the hypoxic myocardium. Because of their unique binding characteristics, H-NOX–based variants effectively deliver O2 to hypoxic tissues, but not those at physiologic O2 tension. Additionally, H-NOX–based variants exhibit tunable binding that is specific for O2 with subphysiologic reactivity towards NO, circumventing a significant toxicity exhibited by hemoglobin (Hb)-based O2 carriers (HBOCs). Juvenile lambs were sedated, mechanically ventilated, and instrumented to measure cardiovascular parameters. Biventricular admittance catheters were inserted to perform pressure-volume (PV) analyses. Systemic hypoxia was induced by ventilation with 10% O2. Following 15 minutes of hypoxia, the lambs were treated with OMX-CV (200 mg/kg IV) or vehicle. Acute hypoxia induced significant increases in heart rate (HR), pulmonary blood flow (PBF), and pulmonary vascular resistance (PVR) (p < 0.05). At 1 hour, vehicle-treated lambs exhibited severe hypoxia and a significant decrease in biventricular contractile function. However, in OMX-CV–treated animals, myocardial oxygenation was improved without negatively impacting systemic or PVR, and both right ventricle (RV) and left ventricle (LV) contractile function were maintained at pre-hypoxic baseline levels. These data suggest that OMX-CV is a promising and safe O2 delivery biotherapeutic for the preservation of myocardial contractility in the setting of acute hypoxia. While hemoglobin is the primary oxygen delivery molecule used to maintain tissue oxygenation in metazoans, many organisms have other heme-containing proteins that can bind oxygen and other diatomic gases. Here, we tested whether a member of the H-NOX family of heme-containing proteins found in the thermostable bacterium Thermoanaerobacter tengcongensis can be engineered to deliver oxygen to severely hypoxic tissues in large mammals. This class of molecules has the advantage of high oxygen affinity and minimal nitric oxide reactivity. We demonstrate that these molecules can effectively deliver oxygen to a lamb heart with induced severe hypoxia, without overexposing the animal to oxygen or triggering systemic vascular reactivity. These molecules thus represent a novel class of oxygen delivery biotherapeutics to specifically target hypoxic tissue beds without the toxicity concerns of hemoglobin-based oxygen carriers. As tissue hypoxia is a central feature of many disease processes, this therapeutic approach may have broad clinical applicability.
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Affiliation(s)
- Jason Boehme
- Department of Pediatrics, University of California, San Francisco, San Francisco, California, United States of America
| | - Natacha Le Moan
- Omniox, Inc., San Carlos, California, United States of America
| | - Rebecca J. Kameny
- Department of Pediatrics, University of California, San Francisco, San Francisco, California, United States of America
| | | | - Michael J. Johengen
- Department of Pediatrics, University of California, San Francisco, San Francisco, California, United States of America
| | - Amy L. Lesneski
- Department of Pediatrics, University of California, San Francisco, San Francisco, California, United States of America
| | - Wenhui Gong
- Department of Pediatrics, University of California, San Francisco, San Francisco, California, United States of America
| | - Brian D. Goudy
- Department of Pediatrics, University of California, San Francisco, San Francisco, California, United States of America
| | - Tina Davis
- Omniox, Inc., San Carlos, California, United States of America
| | - Kevin Tanaka
- Omniox, Inc., San Carlos, California, United States of America
| | - Andrew Davis
- Omniox, Inc., San Carlos, California, United States of America
| | - Youping He
- Department of Pediatrics, University of California, San Francisco, San Francisco, California, United States of America
| | - Janel Long-Boyle
- Department of Clinical Pharmacology, University of California, San Francisco, San Francisco, California, United States of America
- Initiative for Pediatric Drug and Device Development (iPD3), San Francisco, California, United States of America
| | - Vijay Ivaturi
- Initiative for Pediatric Drug and Device Development (iPD3), San Francisco, California, United States of America
- School of Pharmacy, University of Maryland, Baltimore, United States of America
| | - Jogarao V. S. Gobburu
- Initiative for Pediatric Drug and Device Development (iPD3), San Francisco, California, United States of America
- School of Pharmacy, University of Maryland, Baltimore, United States of America
| | | | - Stephen P. Cary
- Omniox, Inc., San Carlos, California, United States of America
| | - Sanjeev A. Datar
- Department of Pediatrics, University of California, San Francisco, San Francisco, California, United States of America
| | - Jeffrey R. Fineman
- Department of Pediatrics, University of California, San Francisco, San Francisco, California, United States of America
- Initiative for Pediatric Drug and Device Development (iPD3), San Francisco, California, United States of America
| | - Ana Krtolica
- Omniox, Inc., San Carlos, California, United States of America
- * E-mail: (AK); (EM)
| | - Emin Maltepe
- Department of Pediatrics, University of California, San Francisco, San Francisco, California, United States of America
- Initiative for Pediatric Drug and Device Development (iPD3), San Francisco, California, United States of America
- * E-mail: (AK); (EM)
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14
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Keramidas ME, Kölegård R, Eiken O. In Shackleton's trails: Central and local thermoadaptive modifications to cold and hypoxia after a man-hauling expedition on the Antarctic Plateau. J Therm Biol 2018; 73:80-90. [PMID: 29549995 DOI: 10.1016/j.jtherbio.2018.02.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Revised: 01/23/2018] [Accepted: 02/25/2018] [Indexed: 11/18/2022]
Abstract
Cold and hypoxia constitute the main environmental stressors encountered on the Antarctic Plateau. Hence, we examined whether central and/or peripheral acclimatisation to the combined stressors of cold and hypoxia would be developed in four men following an 11-day man-hauling expedition on this polar region. Before and after the journey, participants performed a static whole-body immersion in 21 °C water, during which they were breathing a hypoxic gas (partial pressure of inspired O2: ~97 mmHg). To evaluate their local responses to cold, participants also immersed the hand into 8 °C water for 30 min, while they were whole-body immersed and mildly hypothermic [i.e. 0.5 °C fall in rectal temperature (Trec) from individual pre-immersion values]. Trec and skin temperature (Tsk), skin blood flux, and oxygen uptake (reflecting shivering thermogenesis) were monitored throughout. The polar expedition accelerated by ~14 min the drop in Trec [final mean (95% confidence interval) changes in Trec: Before = -0.94 (0.15) °C, After: - 1.17 (0.23) °C]. The shivering onset threshold [Before: 19 (22) min, After: 25 (19) min] and gain [Before: - 4.19 (3.95) mL min-1 kg-1, After: - 1.70 (1.21) mL min-1 kg-1] were suppressed by the expedition. Tsk did not differ between trials. The development of a greater post-expedition hypothermic state did not compromise finger circulation during the hand-cooling phase. Present findings indicate therefore that a hypothermic pattern of cold acclimatisation, as investigated in hypoxia, was developed following a short-term expedition on the South Polar Plateau; an adaptive response that is characterised mainly by suppressed shivering thermogenesis, and partly by blunted cutaneous vasoconstriction.
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Affiliation(s)
- Michail E Keramidas
- Department of Environmental Physiology, Swedish Aerospace Physiology Center, School of Engineering Sciences in Chemistry, Biotechnology and Health, Royal Institute of Technology, Berzelius väg 13, 171 65, Solna, Sweden.
| | - Roger Kölegård
- Department of Environmental Physiology, Swedish Aerospace Physiology Center, School of Engineering Sciences in Chemistry, Biotechnology and Health, Royal Institute of Technology, Berzelius väg 13, 171 65, Solna, Sweden
| | - Ola Eiken
- Department of Environmental Physiology, Swedish Aerospace Physiology Center, School of Engineering Sciences in Chemistry, Biotechnology and Health, Royal Institute of Technology, Berzelius väg 13, 171 65, Solna, Sweden
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15
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Rincon F, Bestle M, Brossner G, Vanderpol J. Unique Uses of Cooling Strategies. Ther Hypothermia Temp Manag 2017; 7:118-121. [PMID: 28813633 DOI: 10.1089/ther.2017.29032.ply] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Fred Rincon
- 1 Department of Neurology, Thomas Jefferson University , Philadelphia, Pennsylvania
| | - Morten Bestle
- 2 Nordsjaellands Hospital, University of Copenhagen , Copenhagen, Denmark
| | - Gregor Brossner
- 3 Neurointensive Care Unit, Department of Neurology, University Hospital , Innsbruck, Austria
| | - Jitka Vanderpol
- 4 Penrith Hospital , Cumbria Partnership NHS Foundation Trust, Cumbria, United Kingdom
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16
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Horiuchi M, Oda S, Uno T, Endo J, Handa Y, Fukuoka Y. Effects of Short-Term Acclimatization at the Summit of Mt. Fuji (3776 m) on Sleep Efficacy, Cardiovascular Responses, and Ventilatory Responses. High Alt Med Biol 2017; 18:171-178. [PMID: 28375664 DOI: 10.1089/ham.2016.0162] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Horiuchi, Masahiro, Shiro Oda, Tadashi Uno, Junko Endo, Yoko Handa, and Yoshiyuki Fukuoka. Effects of short-term acclimatization at the summit of Mt. Fuji (3776 m) on sleep efficacy, cardiovascular responses, and ventilatory responses. High Alt Med Biol. 18:171-178, 2017.-We investigated the effects of a short period of acclimatization, at 3776 m on Mt. Fuji, on sleep parameters and related physiological responses. Physiological responses were assessed in seven healthy lowlander men during both daytime and sleep while at sea level (SL), as well as for three consecutive nights at high altitude (HA; 3776 m, day 1 [D1], D2, D3, and morning only of D4). Blood pressure variables, heart rate (HR), pulmonary ventilation (VE), and breathing frequency (Bf) progressively increased each day, with significant differences between SL and HA (p < 0.05, respectively). In contrast, end-tidal PCO2 (PETCO2) progressively decreased each day with statistical differences between SL and D3 at HA (p < 0.05). During sleep at HA, mean arterial pressure (MAP) was stable, whereas it decreased during sleep at SL. Sleep efficacy, which was assessed by actigraphy, was linearly impaired with statistical differences between SL and D3 (p < 0.05). These impairments in sleep efficacy at HA were associated with higher MAP and HR, as well as lower Bf and PETCO2 during the daytime (pooled data, p < 0.05, respectively). These results suggest that hypoxia-induced cardiovascular and ventilatory responses may be crucial contributors to changes in sleep efficacy at HA.
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Affiliation(s)
- Masahiro Horiuchi
- 1 Division of Human Environmental Science, Mt. Fuji Research Institute , Yamanashi, Japan
| | - Shiro Oda
- 2 Department of Health and Welfare, School of Life Long Sport, Hokusho University , Hokkaido, Japan
| | - Tadashi Uno
- 1 Division of Human Environmental Science, Mt. Fuji Research Institute , Yamanashi, Japan
| | - Junko Endo
- 1 Division of Human Environmental Science, Mt. Fuji Research Institute , Yamanashi, Japan
| | - Yoko Handa
- 1 Division of Human Environmental Science, Mt. Fuji Research Institute , Yamanashi, Japan
| | - Yoshiyuki Fukuoka
- 3 Faculty of Health and Sports Science, Doshisha University , Kyoto, Japan
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Niu X, Li S, Zheng S, Xiong H, Lv J, Zhang H, Liu H. Hypoxia-induced brain cell damage in male albino wistar rat. Saudi J Biol Sci 2017; 25:1473-1477. [PMID: 30505197 PMCID: PMC6252012 DOI: 10.1016/j.sjbs.2017.03.018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Revised: 03/24/2017] [Accepted: 03/28/2017] [Indexed: 12/26/2022] Open
Abstract
The biochemical markers of rat under low oxygen concentration, including brain water level, lactic acid, necrosis and Na+-K+-ATPase, was detected to analyze the hypoxia-induced brain damage, and to analyze the mechanism of brain injury. Histopathological alteration in brain tissue induced by hypoxia were investigated through hematoxylin and eosin stain (HE). Hypoxia induced factor-1a (HIF-1a) expression level in the brain was carried out using immunohistochemistry. Lactic acid level was positively correlated with the level of hypoxia, while concentration-dependent decrease in total Na+-K+-ATPase activity was noted. Hypoxia induced rathad a significant difference on brain water content compared to controls. The level of necrosis and lactic acid level was increased, and the decrease of Na+-K+-ATPase activity was observed. Histopathological examination of brain confirmed that there was neuronal cell death in hippocampal region. HIF-1a expression increased the hypoxia adaptation capability of the rat through the expressions of genes. Lactic acid, Na+-K+-ATPase and HIF-1a plays an important role in brain injury.
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Affiliation(s)
- Xiaoli Niu
- Department of Anesthesiology, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi Province 710004, China
| | - Siyuan Li
- Department of Anesthesiology, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi Province 710004, China
| | - Simin Zheng
- Department of Anesthesiology, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi Province 710004, China
| | - Hongfei Xiong
- Department of Anesthesiology, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi Province 710004, China
| | - Junlin Lv
- Department of Anesthesiology, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi Province 710004, China
| | - Huijuan Zhang
- Department of Anesthesiology, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi Province 710004, China
| | - Hongtao Liu
- Department of Anesthesiology, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi Province 710004, China
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18
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Does the Sympathetic Nervous System Adapt to Chronic Altitude Exposure? ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 903:375-93. [DOI: 10.1007/978-1-4899-7678-9_25] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
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19
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Keramidas ME, Kölegård R, Mekjavic IB, Eiken O. PlanHab: hypoxia exaggerates the bed-rest-induced reduction in peak oxygen uptake during upright cycle ergometry. Am J Physiol Heart Circ Physiol 2016; 311:H453-64. [PMID: 27342877 DOI: 10.1152/ajpheart.00304.2016] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Accepted: 06/20/2016] [Indexed: 11/22/2022]
Abstract
The study examined the effects of hypoxia and horizontal bed rest, separately and in combination, on peak oxygen uptake (V̇o2 peak) during upright cycle ergometry. Ten male lowlanders underwent three 21-day confinement periods in a counterbalanced order: 1) normoxic bed rest [NBR; partial pressure of inspired O2 (PiO2 ) = 133.1 ± 0.3 mmHg]; 2) hypoxic bed rest (HBR; PiO2 = 90.0 ± 0.4 mmHg), and 3) hypoxic ambulation (HAMB; PiO2 = 90.0 ± 0.4 mmHg). Before and after each confinement, subjects performed two incremental-load trials to exhaustion, while inspiring either room air (AIR), or a hypoxic gas (HYPO; PiO2 = 90.0 ± 0.4 mmHg). Changes in regional oxygenation of the vastus lateralis muscle and the frontal cerebral cortex were monitored with near-infrared spectroscopy. Cardiac output (CO) was recorded using a bioimpedance method. The AIR V̇o2 peak was decreased by both HBR (∼13.5%; P ≤ 0.001) and NBR (∼8.6%; P ≤ 0.001), with greater drop after HBR (P = 0.01). The HYPO V̇o2 peak was also reduced by HBR (-9.7%; P ≤ 0.001) and NBR (-6.1%; P ≤ 0.001). Peak CO was lower after both bed-rest interventions, and especially after HBR (HBR: ∼13%, NBR: ∼7%; P ≤ 0.05). Exercise-induced alterations in muscle and cerebral oxygenation were blunted in a similar manner after both bed-rest confinements. No changes were observed in HAMB. Hence, the bed-rest-induced decrease in V̇o2 peak was exaggerated by hypoxia, most likely due to a reduction in convective O2 transport, as indicated by the lower peak values of CO.
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Affiliation(s)
- Michail E Keramidas
- Department of Environmental Physiology, Swedish Aerospace Physiology Center, School of Technology and Health, Royal Institute of Technology, Stockholm, Sweden;
| | - Roger Kölegård
- Department of Environmental Physiology, Swedish Aerospace Physiology Center, School of Technology and Health, Royal Institute of Technology, Stockholm, Sweden
| | - Igor B Mekjavic
- Department of Automation, Biocybernetics and Robotics, Jozef Stefan Institute, Ljubljana, Slovenia; and Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Ola Eiken
- Department of Environmental Physiology, Swedish Aerospace Physiology Center, School of Technology and Health, Royal Institute of Technology, Stockholm, Sweden
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20
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Keramidas ME, Mekjavic IB, Kölegård R, Choukèr A, Strewe C, Eiken O. PlanHab: Hypoxia counteracts the erythropoietin suppression, but seems to exaggerate the plasma volume reduction induced by 3 weeks of bed rest. Physiol Rep 2016; 4:4/7/e12760. [PMID: 27081163 PMCID: PMC4831328 DOI: 10.14814/phy2.12760] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2016] [Accepted: 03/16/2016] [Indexed: 11/24/2022] Open
Abstract
The study examined the distinct and synergistic effects of hypoxia and bed rest on the erythropoietin (EPO) concentration and relative changes in plasma volume (PV). Eleven healthy male lowlanders underwent three 21‐day confinement periods, in a counterbalanced order: (1) normoxic bed rest (NBR; PIO2: 133.1 ± 0.3 mmHg); (2) hypoxic bed rest (HBR; PIO2: 90.0 ± 0.4 mmHg, ambient simulated altitude of ~4000 m); and (3) hypoxic ambulation (HAMB; PIO2: 90.0 ± 0.4 mmHg). Blood samples were collected before, during (days 2, 5, 14, and 21) and 2 days after each confinement to determine EPO concentration. Qualitative differences in PV changes were also estimated by changes in hematocrit and hemoglobin concentration along with concomitant changes in plasma renin concentration. NBR caused an initial reduction in EPO by ~39% (P = 0.04). By contrast, HBR enhanced EPO (P = 0.001), but the increase was less than that induced by HAMB (P < 0.01). All three confinements caused a significant reduction in PV (P < 0.05), with a substantially greater drop in HBR than in the other conditions (P < 0.001). Thus, present results suggest that hypoxia prevents the EPO suppression, whereas it seems to exaggerate the PV reduction induced by bed rest.
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Affiliation(s)
- Michail E Keramidas
- Department of Environmental Physiology, Swedish Aerospace Physiology Center, School of Technology and Health, Royal Institute of Technology, Stockholm, Sweden
| | - Igor B Mekjavic
- Department of Automation, Biocybernetics and Robotics, Jozef Stefan Institute, Ljubljana, Slovenia
| | - Roger Kölegård
- Department of Environmental Physiology, Swedish Aerospace Physiology Center, School of Technology and Health, Royal Institute of Technology, Stockholm, Sweden
| | - Alexander Choukèr
- Department of Anaesthesiology, Stress and Immunology Lab, University of Munich, Munich, Germany
| | - Claudia Strewe
- Department of Anaesthesiology, Stress and Immunology Lab, University of Munich, Munich, Germany
| | - Ola Eiken
- Department of Environmental Physiology, Swedish Aerospace Physiology Center, School of Technology and Health, Royal Institute of Technology, Stockholm, Sweden
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21
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Silva-Urra JA, Núñez-Espinosa CA, Niño-Mendez OA, Gaitán-Peñas H, Altavilla C, Toro-Salinas A, Torrella JR, Pagès T, Javierre CF, Behn C, Viscor G. Circadian and Sex Differences After Acute High-Altitude Exposure: Are Early Acclimation Responses Improved by Blue Light? Wilderness Environ Med 2015; 26:459-71. [PMID: 26254125 DOI: 10.1016/j.wem.2015.06.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Revised: 04/30/2015] [Accepted: 06/11/2015] [Indexed: 10/23/2022]
Abstract
OBJECTIVE The possible effects of blue light during acute hypoxia and the circadian rhythm on several physiological and cognitive parameters were studied. METHODS Fifty-seven volunteers were randomly assigned to 2 groups: nocturnal (2200-0230 hours) or diurnal (0900-1330 hours) and exposed to acute hypoxia (4000 m simulated altitude) in a hypobaric chamber. The participants were illuminated by blue LEDs or common artificial light on 2 different days. During each session, arterial oxygen saturation (Spo2), blood pressure, heart rate variability, and cognitive parameters were measured at sea level, after reaching the simulated altitude of 4000 m, and after 3 hours at this altitude. RESULTS The circadian rhythm caused significant differences in blood pressure and heart rate variability. A 4% to 9% decrease in waking nocturnal Spo2 under acute hypoxia was observed. Acute hypoxia also induced a significant reduction (4%-8%) in systolic pressure, slightly more marked (up to 13%) under blue lighting. Women had significantly increased systolic (4%) and diastolic (12%) pressures under acute hypoxia at night compared with daytime pressure; this was not observed in men. Some tendencies toward better cognitive performance (d2 attention test) were seen under blue illumination, although when considered together with physiological parameters and reaction time, there was no conclusive favorable effect of blue light on cognitive fatigue suppression after 3 hours of acute hypobaric hypoxia. CONCLUSIONS It remains to be seen whether longer exposure to blue light under hypobaric hypoxic conditions would induce favorable effects against fatigue.
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Affiliation(s)
- Juan A Silva-Urra
- Departamento Biomédico, Universidad de Antofagasta, Antofagasta, Chile
| | | | - Oscar A Niño-Mendez
- Departament de Ciències Fisiològiques II, Universitat de Barcelona, Barcelona, Spain
| | | | | | | | | | | | - Casimiro F Javierre
- Departament de Ciències Fisiològiques II, Universitat de Barcelona, Barcelona, Spain
| | - Claus Behn
- Laboratorio de Ambientes Extremos (ICBM), Universidad de Chile, Santiago de Chile, Chile
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22
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Lu H, Wang R, Xiong J, Xie H, Kayser B, Jia Z. In search for better pharmacological prophylaxis for acute mountain sickness: looking in other directions. Acta Physiol (Oxf) 2015; 214:51-62. [PMID: 25778288 DOI: 10.1111/apha.12490] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Revised: 02/23/2015] [Accepted: 03/11/2015] [Indexed: 12/15/2022]
Abstract
Despite decades of research, the exact pathogenic mechanisms underlying acute mountain sickness (AMS) are still poorly understood. This fact frustrates the search for novel pharmacological prophylaxis for AMS. The prevailing view is that AMS results from an insufficient physiological response to hypoxia and that prophylaxis should aim at stimulating the response. Starting off from the opposite hypothesis that AMS may be caused by an initial excessive response to hypoxia, we suggest that directly or indirectly blunting-specific parts of the response might provide promising research alternatives. This reasoning is based on the observations that (i) humans, once acclimatized, can climb Mt Everest experiencing arterial partial oxygen pressures (PaO2) as low as 25 mmHg without AMS symptoms; (ii) paradoxically, AMS usually develops at much higher PaO2 levels; and (iii) several biomarkers, suggesting initial activation of specific pathways at such PaO2, are correlated with AMS. Apart from looking for substances that stimulate certain hypoxia triggered effects, such as the ventilatory response to hypoxia, we suggest to also investigate pharmacological means aiming at blunting certain other specific hypoxia-activated pathways, or stimulating their agonists, in the quest for better pharmacological prophylaxis for AMS.
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Affiliation(s)
- H. Lu
- Key Laboratory of the Plateau of Environmental Damage Control; Lanzhou General Hospital of Lanzhou Military Command; Lanzhou China
| | - R. Wang
- Key Laboratory of the Plateau of Environmental Damage Control; Lanzhou General Hospital of Lanzhou Military Command; Lanzhou China
| | - J. Xiong
- Key Laboratory of the Plateau of Environmental Damage Control; Lanzhou General Hospital of Lanzhou Military Command; Lanzhou China
| | - H. Xie
- Key Laboratory of the Plateau of Environmental Damage Control; Lanzhou General Hospital of Lanzhou Military Command; Lanzhou China
| | - B. Kayser
- Institute of Sports Sciences and Department of Physiology; University of Lausanne; Lausanne Switzerland
| | - Z.P. Jia
- Key Laboratory of the Plateau of Environmental Damage Control; Lanzhou General Hospital of Lanzhou Military Command; Lanzhou China
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23
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Siques P, Brito J, Naveas N, Pulido R, De la Cruz JJ, Mamani M, León-Velarde F. Plasma and liver lipid profiles in rats exposed to chronic hypobaric hypoxia: changes in metabolic pathways. High Alt Med Biol 2014; 15:388-95. [PMID: 25185022 DOI: 10.1089/ham.2013.1134] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Lipid metabolism under chronic hypoxia (CH) has not received equal attention as intermittent hypoxia (IH). To determine the CH-induced changes in plasma and liver, as well as the mRNA and protein expression of two key enzymes in the triglyceride and cholesterol biosynthesis pathways, SREBP-1 (HMG-CoA reductase) and SREBP-2 (SCD-1), we exposed adult male Wistar rats to CH (4600 m; n=15) for 30 days compared to normoxic rats (n=15). The CH rats exhibited weight loss (p<0.001), higher hematocrit (%), and higher hemoglobin (g/dL) (p<0.01). In the plasma of CH rats, total cholesterol and LDL-cholesterol increased at day 15. VLDL-cholesterol and triglycerides (p<0.01) greatly increased (35%), while HDL-cholesterol decreased (p<0.01). Triglycerides and VLDL-cholesterol remained elevated by 28% at day 30 (p<0.01). Hepatic triglycerides increased two-fold, while total cholesterol increased by 51% (p<0.001; p<0.05). Upregulation of SCD-1 mRNA and protein was observed in the CH rats (p<0.01); however, no differences were observed in HMG-CoA reductase mRNA or protein expression in both groups. In conclusion, CH, like IH, alters lipid profiles by increasing triglycerides in the plasma and liver and upregulating triglyceride biosynthesis without affecting the cholesterol biosynthetic pathway. Additional involved mechanisms require further study because of the importance of lipids in cardiovascular risk.
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Affiliation(s)
- Patricia Siques
- 1 Institute of Health Studies. Universidad Arturo Prat , Iquique, Chile
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24
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Keramidas ME, Kölegård R, Mekjavic IB, Eiken O. Hand temperature responses to local cooling after a 10-day confinement to normobaric hypoxia with and without exercise. Scand J Med Sci Sports 2014; 25:650-60. [DOI: 10.1111/sms.12291] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/17/2014] [Indexed: 11/29/2022]
Affiliation(s)
- M. E. Keramidas
- Department of Environmental Physiology, School of Technology and Health; Royal Institute of Technology; Stockholm Sweden
| | - R. Kölegård
- Department of Environmental Physiology, School of Technology and Health; Royal Institute of Technology; Stockholm Sweden
| | - I. B. Mekjavic
- Department of Automation, Biocybernetics and Robotics; Jozef Stefan Institute; Ljubljana Slovenia
| | - O. Eiken
- Department of Environmental Physiology, School of Technology and Health; Royal Institute of Technology; Stockholm Sweden
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Schultz MG, Climie RED, Sharman JE. Ambulatory and central haemodynamics during progressive ascent to high-altitude and associated hypoxia. J Hum Hypertens 2014; 28:705-10. [PMID: 24621622 DOI: 10.1038/jhh.2014.15] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Revised: 01/20/2014] [Accepted: 01/23/2014] [Indexed: 11/09/2022]
Abstract
High-altitude hypoxia causes major cardiovascular changes, which may result in raised resting brachial blood pressure (BP). However, the effect of high-altitude hypoxia on more sensitive measures of BP control (such as 24 h ambulatory BP and resting central BP) is largely unknown. This study aimed to assess this and compare high-altitude responses to resting brachial BP, as well as determine the haemodynamic correlates of acute mountain sickness (AMS) during a progressive trekking ascent to high-altitude. Measures of oxygen saturation (pulse oximetry), 24 h ambulatory BP, resting brachial and central BP (Pulsecor) were recorded in 10 adults (aged 27±4, 30% male) during a 9-day trek to Mount Everest base camp, Nepal. Data were recorded at sea level (stage 1; <450 m above sea level (ASL)) and at progressive ascension to 3440 m ASL (stage 2), 4350 m ASL (stage 3) and 5164 m ASL (stage 4). The Lake Louise score (LLS) was used to quantify AMS symptoms. Total LLS increased stepwise from sea level to stage 4 (0.3±0.7 vs 4.4±2.0, P=0.012), whereas oxygen saturation decreased to 77±9% (P=0.001). The highest recordings of 24 h ambulatory, daytime, night time, brachial and central systolic BP and diastolic BP were achieved at stage 3, which were significantly greater than at sea level (P<0.005 for all). Twenty-four-hour ambulatory heart rate (HR) and night HR correlated with oxygen saturation (r=-0.741 and -0.608, both P<0.001) and total LLS (r=0.648 and r=0.493, both P<0.001). We conclude that 24 h ambulatory BP, central BP and HR are elevated during high-altitude hypoxia, but AMS symptoms are only related to tachycardia.
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Affiliation(s)
- M G Schultz
- Menzies Research Institute Tasmania, University of Tasmania, Hobart, Tasmania, Australia
| | - R E D Climie
- Menzies Research Institute Tasmania, University of Tasmania, Hobart, Tasmania, Australia
| | - J E Sharman
- Menzies Research Institute Tasmania, University of Tasmania, Hobart, Tasmania, Australia
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Correlation between blood pressure changes and AMS, sleeping quality and exercise upon high-altitude exposure in young Chinese men. Mil Med Res 2014; 1:19. [PMID: 25722875 PMCID: PMC4340834 DOI: 10.1186/2054-9369-1-19] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/27/2014] [Accepted: 07/17/2014] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND Excessive elevation of arterial blood pressure (BP) at high altitude can be detrimental to our health due to acute mountain sickness (AMS) or some AMS symptoms. This prospective and observational study aimed to elucidate blood pressure changes induced by exposure to high-altitude hypoxia and the relationships of these changes with AMS prevalence, AMS severity, sleep quality and exercise condition in healthy young men. METHODS A prospective observational study was performed in 931 male young adults exposed to high altitude at 3,700 m (Lhasa) from low altitude (LA, 500 m). Blood pressure measurement and AMS symptom questionnaires were performed at LA and on day 1, 3, 5, and 7 of exposure to high altitude. Lake Louise criteria were used to diagnose AMS. Likewise, the Athens Insomnia Scale (AIS) and the Epworth Sleepiness Scale (ESS) were filled out at LA and on day 1, 3, and 7 of exposure to high altitude. RESULTS After acute exposure to 3,700 m, diastolic blood pressure (DBP) and mean arterial blood pressure (MABP) rose gradually and continually (P < 0.05). Analysis showed a relationship with AMS for only MABP (P < 0.05) but not for SBP and DBP (P > 0.05). Poor sleeping quality was generally associated with higher SBP or DBP at high altitude, although inconsistent results were obtained at different time (P < 0.05). SBP and Pulse BP increased noticeably after high-altitude exercise (P < 0.05). CONCLUSIONS Our data demonstrate notable blood pressure changes under exposure to different high-altitude conditions: 1) BP increased over time. 2) Higher BP generally accompanied poor sleeping quality and higher incidence of AMS. 3) SBP and Pulse BP were higher after high-altitude exercise. Therefore, we should put more effort into monitoring BP after exposure to high altitude in order to guard against excessive increases in BP.
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Dempsey JA, Powell FL, Bisgard GE, Blain GM, Poulin MJ, Smith CA. Role of chemoreception in cardiorespiratory acclimatization to, and deacclimatization from, hypoxia. J Appl Physiol (1985) 2013; 116:858-66. [PMID: 24371017 DOI: 10.1152/japplphysiol.01126.2013] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
During sojourn to high altitudes, progressive time-dependent increases occur in ventilation and in sympathetic nerve activity over several days, and these increases persist upon acute restoration of normoxia. We discuss evidence concerning potential mediators of these changes, including the following: 1) correction of alkalinity in cerebrospinal fluid; 2) increased sensitivity of carotid chemoreceptors; and 3) augmented translation of carotid chemoreceptor input (at the level of the central nervous system) into increased respiratory motor output via sensitization of hypoxic sensitive neurons in the central nervous system and/or an interdependence of central chemoreceptor responsiveness on peripheral chemoreceptor sensory input. The pros and cons of chemoreceptor sensitization and cardiorespiratory acclimatization to hypoxia and intermittent hypoxemia are also discussed in terms of their influences on arterial oxygenation, the work of breathing, sympathoexcitation, systemic blood pressure, and exercise performance. We propose that these adaptive processes may have negative implications for the cardiovascular health of patients with sleep apnea and perhaps even for athletes undergoing regimens of "sleep high-train low"!
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Stöwhas AC, Latshang TD, Lo Cascio CM, Lautwein S, Stadelmann K, Tesler N, Ayers L, Berneis K, Gerber PA, Huber R, Achermann P, Bloch KE, Kohler M. Effects of acute exposure to moderate altitude on vascular function, metabolism and systemic inflammation. PLoS One 2013; 8:e70081. [PMID: 23936377 PMCID: PMC3731354 DOI: 10.1371/journal.pone.0070081] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2013] [Accepted: 06/13/2013] [Indexed: 11/24/2022] Open
Abstract
Background Travel to mountain areas is popular. However, the effects of acute exposure to moderate altitude on the cardiovascular system and metabolism are largely unknown. Objectives To investigate the effects of acute exposure to moderate altitude on vascular function, metabolism and systemic inflammation. Methods In 51 healthy male subjects with a mean (SD) age of 26.9 (9.3) years, oxygen saturation, blood pressure, heart rate, arterial stiffness, lipid profiles, low density lipoprotein (LDL) particle size, insulin resistance (HOMA-index), highly-sensitive C-reactive protein and pro-inflammatory cytokines were measured at 490 m (Zurich) and during two days at 2590 m, (Davos Jakobshorn, Switzerland) in randomized order. The largest differences in outcomes between the two altitudes are reported. Results Mean (SD) oxygen saturation was significantly lower at 2590 m, 91.0 (2.0)%, compared to 490 m, 96.0 (1.0)%, p<0.001. Mean blood pressure (mean difference +4.8 mmHg, p<0.001) and heart rate (mean difference +3.3 bpm, p<0.001) were significantly higher at 2590 m, compared to 490 m, but this was not associated with increased arterial stiffness. At 2590 m, lipid profiles improved (median difference triglycerides −0.14 mmol/l, p = 0.012, HDL +0.08 mmol/l, p<0.001, total cholesterol/HDL-ratio −0.25, p = 0.001), LDL particle size increased (median difference +0.45 nm, p = 0.048) and hsCRP decreased (median difference −0.18 mg/l, p = 0.024) compared to 490 m. No significant change in pro-inflammatory cytokines or insulin resistance was observed upon ascent to 2590 m. Conclusions Short-term stay at moderate altitude is associated with increased blood pressure and heart rate likely due to augmented sympathetic activity. Exposure to moderate altitude improves the lipid profile and systemic inflammation, but seems to have no significant effect on glucose metabolism. Trial Registration ClinicalTrials.gov NCT01130948
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Affiliation(s)
| | | | | | - Sina Lautwein
- Pulmonary Division, University Hospital Zurich, Zurich, Switzerland
| | - Katrin Stadelmann
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
| | - Noemi Tesler
- Child Development Centre, University Children's Hospital Zurich, Zurich, Switzerland
| | - Lisa Ayers
- Department of Clinical Immunology, Churchill Hospital, Oxford, United Kingdom
| | - Kaspar Berneis
- Department of Endocrinology, Diabetes and Nutrition, University Hospital Zurich, Zurich, Switzerland
| | - Philipp A. Gerber
- Department of Endocrinology, Diabetes and Nutrition, University Hospital Zurich, Zurich, Switzerland
| | - Reto Huber
- Child Development Centre, University Children's Hospital Zurich, Zurich, Switzerland
- Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland
| | - Peter Achermann
- Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland
- Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland
| | - Konrad E. Bloch
- Pulmonary Division, University Hospital Zurich, Zurich, Switzerland
- Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland
| | - Malcolm Kohler
- Pulmonary Division, University Hospital Zurich, Zurich, Switzerland
- Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland
- * E-mail:
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Richter S, Qin N, Pacak K, Eisenhofer G. Role of hypoxia and HIF2α in development of the sympathoadrenal cell lineage and chromaffin cell tumors with distinct catecholamine phenotypic features. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2013; 68:285-317. [PMID: 24054150 DOI: 10.1016/b978-0-12-411512-5.00014-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Hypoxia has wide-ranging impact in normal physiology and disease processes. This stimulus evokes changes in gene expression mediated by transcription factors termed hypoxia-inducible factors (HIFs) that affect numerous processes: angiogenesis, cell survival, cellular metabolism, stem cell self-renewal and multipotency, migration, invasiveness, and metastatic progression in tumor cells. Over the past decade, increasing numbers of reports have emerged documenting differential roles of HIF1α and HIF2α in these processes. In cells of the sympathoadrenal lineage, both HIFs differentially mediate influences of hypoxia on catecholamine synthesis and secretion, but HIF2α signaling has particularly prominent functions in regulating developmental processes of growth and differentiation. This chapter discusses the role of HIF2α and HIF1α in the context of the development, phenotypic features, and functions of chromaffin cells. Moreover, current knowledge about tumor formation in cells of the sympathoadrenal lineage, leading to catecholamine-producing pheochromocytomas and paragangliomas, is analyzed in the light of the HIF2α signaling network.
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Affiliation(s)
- Susan Richter
- Department of Clinical Chemistry and Laboratory Medicine, University Hospital Carl Gustav Carus Dresden, Dresden University of Technology, Dresden, Germany.
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Mirrakhimov AE. Chronic obstructive pulmonary disease and glucose metabolism: a bitter sweet symphony. Cardiovasc Diabetol 2012; 11:132. [PMID: 23101436 PMCID: PMC3499352 DOI: 10.1186/1475-2840-11-132] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2012] [Accepted: 10/04/2012] [Indexed: 01/05/2023] Open
Abstract
Chronic obstructive pulmonary disease, metabolic syndrome and diabetes mellitus are common and underdiagnosed medical conditions. It was predicted that chronic obstructive pulmonary disease will be the third leading cause of death worldwide by 2020. The healthcare burden of this disease is even greater if we consider the significant impact of chronic obstructive pulmonary disease on the cardiovascular morbidity and mortality. Chronic obstructive pulmonary disease may be considered as a novel risk factor for new onset type 2 diabetes mellitus via multiple pathophysiological alterations such as: inflammation and oxidative stress, insulin resistance, weight gain and alterations in metabolism of adipokines. On the other hand, diabetes may act as an independent factor, negatively affecting pulmonary structure and function. Diabetes is associated with an increased risk of pulmonary infections, disease exacerbations and worsened COPD outcomes. On the top of that, coexistent OSA may increase the risk for type 2 DM in some individuals. The current scientific data necessitate a greater outlook on chronic obstructive pulmonary disease and chronic obstructive pulmonary disease may be viewed as a risk factor for the new onset type 2 diabetes mellitus. Conversely, both types of diabetes mellitus should be viewed as strong contributing factors for the development of obstructive lung disease. Such approach can potentially improve the outcomes and medical control for both conditions, and, thus, decrease the healthcare burden of these major medical problems.
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MESH Headings
- Adipokines/blood
- Adult
- Aged
- Animals
- Blood Glucose/metabolism
- Comorbidity
- Diabetes Mellitus, Type 2/blood
- Diabetes Mellitus, Type 2/diagnosis
- Diabetes Mellitus, Type 2/epidemiology
- Diabetes Mellitus, Type 2/physiopathology
- Diabetes Mellitus, Type 2/therapy
- Endothelium, Vascular/metabolism
- Endothelium, Vascular/physiopathology
- Female
- Humans
- Inflammation Mediators/blood
- Lung/metabolism
- Lung/physiopathology
- Male
- Middle Aged
- Oxidative Stress
- Prognosis
- Pulmonary Disease, Chronic Obstructive/blood
- Pulmonary Disease, Chronic Obstructive/diagnosis
- Pulmonary Disease, Chronic Obstructive/epidemiology
- Pulmonary Disease, Chronic Obstructive/physiopathology
- Pulmonary Disease, Chronic Obstructive/therapy
- Risk Factors
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Affiliation(s)
- Aibek E Mirrakhimov
- Kyrgyz State Medical Academy named by I,K, Akhunbaev, Akhunbaev street 92, Bishkek 720020, Kyrgyzstan.
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31
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Swenson ER. CON: Most Climbers Do Not Develop Subclinical Interstitial Pulmonary Edema. High Alt Med Biol 2011; 12:125-8; discussion 129-30. [DOI: 10.1089/ham.2011.0005] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Erik R. Swenson
- VA Puget Sound Health Care System, University of Wasington, Seattle, Washington
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Rhodes HL, Chesterman K, Chan CW, Collins P, Kewley E, Pattinson KTS, Myers S, Imray CHE, Wright AD. Systemic blood pressure, arterial stiffness and pulse waveform analysis at altitude. J ROY ARMY MED CORPS 2011; 157:110-3. [PMID: 21465920 DOI: 10.1136/jramc-157-01-18] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
OBJECTIVES Systemic arterial pressure rises on acute exposure to high altitude and changes in blood pressure (BP) and endothelial function may be important in the pathogenesis of clinical syndromes occurring at high altitude. METHODS Arterial BP, stiffness (SI) and tone (RI) were studied over 11 days in 17 subjects (three having mild hypertension) ascending to 3,450m and 4,770m using a non-invasive, finger photoplethysmography technique. RESULTS At 3,450m BP rose from mean 131/75 mmHg (SD 23/12) to 145/86 (23/12) and was maintained at this level (p < 0.001). SI did not change significantly from 8.5 m/sec (2.5) to 9.7 (3.2). RI fell during the first day at 3,450m from 74.4% (7.9) to 70.5% (13.8) (NS p > 0.05) and to 69.9% (12.0) (p < 0.02) at 4,770m but then reverted to baseline. Changes in SI and RI did not relate to changes in blood pressure. Changes in both arterial stiffness and tone were similar in those who developed AMS compared with those who did not. Baseline SI tended to be higher in the three subjects with hypertension 11.1m/sec (SD 2.7)) compared with the normotensives 8.3 m/sec (SD 2.7) (NS) and baseline RI lower 74.7% (7.0) compared with the normotensives 76.5% (8.5) (NS). Changes in SI and RI at altitude in the hypertensive subjects were similar to the non-hypertensive subjects. CONCLUSIONS We conclude that acute exposure temporarily affected endothelial function as measured by a change in vascular tone but this did not predict the development of AMS. The rise in arterial BP was not related to changes in arterial stiffness or tone.
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Affiliation(s)
- H L Rhodes
- Wirral University Teaching Hospital, Upton, Wirral
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Berger MM, Luks AM, Bailey DM, Menold E, Robotti GC, Mairbäurl H, Dehnert C, Swenson ER, Bärtsch P. Transpulmonary Plasma Catecholamines in Acute High-Altitude Pulmonary Hypertension. Wilderness Environ Med 2011; 22:37-45. [DOI: 10.1016/j.wem.2010.11.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2010] [Revised: 10/30/2010] [Accepted: 11/19/2010] [Indexed: 11/16/2022]
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Siqués P, Brito J, Banegas JR, León-Velarde F, de la Cruz-Troca JJ, López V, Naveas N, Herruzo R. Blood Pressure Responses in Young Adults First Exposed to High Altitude for 12 Months at 3550 m. High Alt Med Biol 2009; 10:329-35. [DOI: 10.1089/ham.2008.1103] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Patricia Siqués
- Institute of Health Studies, Universidad Arturo Prat, Iquique, Chile
| | - Julio Brito
- Institute of Health Studies, Universidad Arturo Prat, Iquique, Chile
| | - Jose R. Banegas
- Department of Preventive Medicine and Public Health, Universidad Autónoma de Madrid, and CIBER en Epidemiología y Salud Pública, Spain
| | - Fabiola León-Velarde
- Department of Biological and Physiological Sciences, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Peru
| | - Juan J. de la Cruz-Troca
- Department of Preventive Medicine and Public Health, Universidad Autónoma de Madrid, and CIBER en Epidemiología y Salud Pública, Spain
| | - Vasthi López
- Institute of Health Studies, Universidad Arturo Prat, Iquique, Chile
| | - Nelson Naveas
- Institute of Health Studies, Universidad Arturo Prat, Iquique, Chile
| | - Rafael Herruzo
- Department of Preventive Medicine and Public Health, Universidad Autónoma de Madrid, and CIBER en Epidemiología y Salud Pública, Spain
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Snow AB, Khalyfa A, Serpero LD, Capdevila OS, Kim J, Buazza MO, Gozal D. Catecholamine alterations in pediatric obstructive sleep apnea: effect of obesity. Pediatr Pulmonol 2009; 44:559-67. [PMID: 19431192 DOI: 10.1002/ppul.21015] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
STUDY OBJECTIVES Obstructive sleep apnea (OSA) elicits increased sympathetic activity in adults and increased urinary catecholamines. Moreover, urinary catecholamine excretion is altered in obese patients. We hypothesized that morning urine catecholamine levels would be correlated with the severity of obstructive sleep apnea and degree of obesity in children. METHODS Children referred to the pediatric sleep center for habitual snoring underwent overnight polysomnography, and the first morning voided urine sample was collected. Urinary concentrations of norepinephrine, epinephrine and dopamine were measured and corrected for creatinine levels. In a subset of children, blood samples were drawn and gene expression of catecholamine-relevant genes analyzed by quantitative real-time PCR. RESULTS One hundred fifty-nine children were recruited and completed the protocol. Children with OSA had significantly higher urinary norepinephrine and epinephrine levels, but not dopamine, compared to habitual snorers (norepinephrine: 40.1 +/- 24.7 ng/mg creatinine vs. 31.6 +/- 16.2 ng/mg creatinine, P < 0.01; epinephrine: 6.4 +/- 10.5 ng/mg vs. 4.5 +/- 0.5 ng/mg, P < 0.01). There was a positive correlation between norepinephrine and epinephrine values and polysomnographic indices, but no effect of obesity on catecholamine levels. In addition, expression of several of the major genes involved in synthesis and transport of catecholamines, as well as in selected receptors were compatible with increased bioavailability of catecholamines. CONCLUSIONS In children with OSA, morning urinary norepinephrine and epinephrine levels are significantly higher than those without OSA, and correlate with the severity of the disease. Gene expression patterns are in agreement with such findings. Urine catecholamine levels do not appear to be influenced by the presence of obesity. Thus, altered sympathetic activity in OSA patients appears to occur independently of the presence of obesity.
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Affiliation(s)
- Ayelet B Snow
- Division of Pediatric Sleep Medicine and Kosair Children's Hospital Research Institute, Department of Pediatrics, University of Louisville, Louisville, KY 40202, USA
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Hu DY, Li Q, Li B, Dai RJ, Geng LN, Deng YL. Normobaric hypoxia-induced brain damage in wistar rat. ACTA ACUST UNITED AC 2009. [DOI: 10.4236/jbise.2009.28092] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Kaditis AG, Alexopoulos EI, Damani E, Hatzi F, Chaidas K, Kostopoulou T, Tzigeroglou A, Gourgoulianis K. Urine levels of catecholamines in Greek children with obstructive sleep-disordered breathing. Pediatr Pulmonol 2009; 44:38-45. [PMID: 19085921 DOI: 10.1002/ppul.20916] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
INTRODUCTION Adults with obstructive sleep apnea have increased sympathetic activity. It was hypothesized that in children with symptoms of obstructive sleep-disordered breathing (SDB), morning urine levels of catecholamines correlate with severity of nocturnal hypoxemia. METHODS Children with snoring referred for polysomnography and controls without snoring were recruited. Morning urine norepinephrine, epinephrine, normetanephrine, and metanephrine levels were measured (ng/mg urine creatinine). RESULTS Twelve children (age 5.2 +/- 2.3 years) with severe hypoxemia (oxygen saturation of hemoglobin-SpO2 nadir < or =86%), 20 subjects (age 6.1 +/- 2.1 years) with moderate hypoxemia (SpO2 nadir < or =90% and >86%), 22 children (age 6.6 +/- 1.5 years) with mild nocturnal hypoxemia (SpO2 nadir >90%), and 10 controls (age 7.1 +/- 2.8 years) were studied. Children with severe hypoxemia had significantly higher log-transformed norepinephrine levels (1.63 +/- 0.29) compared to those with moderate hypoxemia (1.43 +/- 0.22; P < 0.05) or compared to controls (1.39 +/- 0.31; P < 0.05). In subjects with SDB, log-transformed oxygen desaturation of hemoglobin index or SpO2 nadir predicted log-transformed norepinephrine levels after adjustment by age, gender and body mass index (r2 = 0.24; and r2 = 0.24, respectively; P < 0.01). CONCLUSIONS Severity of nocturnal hypoxemia in children with intermittent upper airway obstruction during sleep correlates with morning urine levels of norepinephrine suggesting increased sympathetic tone.
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Affiliation(s)
- Athanasios G Kaditis
- Sleep Disorders Laboratory, University of Thessaly School of Medicine, Larissa University Hospital, Larissa, Greece.
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Modulatory effects of seabuckthorn (Hippophae rhamnoides L.) in hypobaric hypoxia induced cerebral vascular injury. Brain Res Bull 2008; 77:246-52. [DOI: 10.1016/j.brainresbull.2008.08.026] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2008] [Revised: 07/18/2008] [Accepted: 08/29/2008] [Indexed: 11/21/2022]
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39
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Strapazzon G, Cogo A, Semplicini A. Acute Mountain Sickness in a Subject with Metabolic Syndrome at High Altitude. High Alt Med Biol 2008; 9:245-8. [DOI: 10.1089/ham.2007.1075] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Giacomo Strapazzon
- Department of Clinical and Experimental Medicine, University of Padova, Italy
| | - Annalisa Cogo
- Sport Biomedical Study Centre, University of Ferrara, Ferrara, Italy
| | - Andrea Semplicini
- Department of Clinical and Experimental Medicine, University of Padova, Italy
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40
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Blood pressure changes in young male subjects exposed to a median altitude. Clin Auton Res 2008; 18:84-9. [DOI: 10.1007/s10286-008-0459-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2007] [Accepted: 03/05/2008] [Indexed: 10/22/2022]
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41
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Jia X, Koenig MA, Shin HC, Zhen G, Pardo CA, Hanley DF, Thakor NV, Geocadin RG. Improving neurological outcomes post-cardiac arrest in a rat model: immediate hypothermia and quantitative EEG monitoring. Resuscitation 2007; 76:431-42. [PMID: 17936492 DOI: 10.1016/j.resuscitation.2007.08.014] [Citation(s) in RCA: 119] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2007] [Revised: 07/23/2007] [Accepted: 08/02/2007] [Indexed: 11/25/2022]
Abstract
OBJECTIVES Therapeutic hypothermia (TH) after cardiac arrest (CA) improves outcomes in a fraction of patients. To enhance the administration of TH, we studied brain electrophysiological monitoring in determining the benefit of early initiation of TH compared to conventional administration in a rat model. METHODS Using an asphyxial CA model, we compared the benefit of immediate hypothermia (IH, T=33 degrees C, immediately post-resuscitation, maintained 6h) to conventional hypothermia (CH, T=33 degrees C, starting 1h post-resuscitation, maintained 12h) via surface cooling. We tracked quantitative EEG using relative entropy (qEEG) with outcome verification by serial Neurological Deficit Score (NDS) and quantitative brain histopathological damage scoring (HDS). Thirty-two rats were divided into 4 groups based on CH/IH and 7/9-min duration of asphyxial CA. Four sham rats were included for evaluation of the effect of hypothermia on qEEG. RESULTS The 72-h NDS of the IH group was significantly better than the CH group for both 7-min (74/63; median, IH/CH, p<0.001) and 9-min (54/47, p=0.022) groups. qEEG showed greater recovery with IH (p<0.001) and significantly less neuronal cortical injury by HDS (IH: 18.9+/-2.5% versus CH: 33.2+/-4.4%, p=0.006). The 1-h post-resuscitation qEEG correlated well with 72-h NDS (p<0.05) and 72-h behavioral subgroup of NDS (p<0.01). No differences in qEEG were noted in the sham group. CONCLUSIONS Immediate but shorter hypothermia compared to CH leads to better functional outcome in rats after 7- and 9-min CA. The beneficial effect of IH was readily detected by neuro-electrophysiological monitoring and histological changes supported the value of this observation.
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Affiliation(s)
- Xiaofeng Jia
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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Verratti V, Di Giulio C, Berardinelli F, Pellicciotta M, Di Francesco S, Iantorno R, Nicolai M, Gidaro S, Tenaglia R. The role of hypoxia in erectile dysfunction mechanisms. Int J Impot Res 2007; 19:496-500. [PMID: 17538640 DOI: 10.1038/sj.ijir.3901560] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Chronic hypoxia is related to many pathological conditions: aging, heart and respiratory failure, sleep apneas, smoke, chronic obstructive pulmonary disease (COPD), diabetes, hypertension and arteriosclerosis, all characterized by reductions of sleep-related erections (SREs) and by erectile dysfunction (ED). Sleep-related erections occur naturally during rapid eye movement (REM) sleep in sexually potent men. Hypoxia is also a physiological condition at altitude. The level of inspired oxygen decreases progressively with the increase of altitude; for this reason, this study was performed to evaluate the relationship of SREs with hypoxic environment. SREs have been recorded by an erectometer (RigiScan) on three mountain climbers (mean age: 32.5) during a 26-day stay at an altitude ranging from 2000 to 5600 m above sea level. Twenty-four records have been made at progressively increasing altitudes. A data analysis was carried out on a statistical mean of the three values of each variable and an analysis of variance (ANOVA) and Newman-Keuls test were carried out for multiple comparison among groups. At altitudes over 4450 m, we found lack of rigidity at 80-100% and 60-79%. Mean % of rigidity and rigidity time of 80-100% (tip and base) decreased progressively with altitude. No significant reductions were shown in rigidity time at 0-19% and at 20-39% (tip and base), of total number, of total and mean duration of SREs. Pathological rigidometric records at high altitude in sexually potent men at sea level clarify the primary role of hypoxia in physiopathological ED pathway.
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Affiliation(s)
- V Verratti
- Department of Medicine and Aging Science, G.d' Annunzio University, Chieti, Italy.
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Ainslie PN, Burgess K, Subedi P, Burgess KR. Alterations in cerebral dynamics at high altitude following partial acclimatization in humans: wakefulness and sleep. J Appl Physiol (1985) 2007; 102:658-64. [PMID: 17053102 DOI: 10.1152/japplphysiol.00911.2006] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
We tested the hypothesis that, following exposure to high altitude, cerebrovascular reactivity to CO2 and cerebral autoregulation would be attenuated. Such alterations may predispose to central sleep apnea at high altitude by promoting changes in brain Pco2 and thus breathing stability. We measured middle cerebral artery blood flow velocity (MCAv; transcranial Doppler ultrasound) and arterial blood pressure during wakefulness in conditions of eucapnia (room air), hypocapnia (voluntary hyperventilation), and hypercapnia (isooxic rebeathing), and also during non-rapid eye movement (stage 2) sleep at low altitude (1,400 m) and at high altitude (3,840 m) in five individuals. At each altitude, sleep was studied using full polysomnography, and resting arterial blood gases were obtained. During wakefulness and polysomnographic-monitored sleep, dynamic cerebral autoregulation and steady-state changes in MCAv in relation to changes in blood pressure were evaluated using transfer function analysis. High altitude was associated with an increase in central sleep apnea index (0.2 ± 0.4 to 20.7 ± 23.2 per hour) and an increase in mean blood pressure and cerebrovascular resistance during wakefulness and sleep. MCAv was unchanged during wakefulness, whereas there was a greater decrease during sleep at high altitude compared with low altitude (−9.1 ± 1.7 vs. −4.8 ± 0.7 cm/s; P < 0.05). At high altitude, compared with low altitude, the cerebrovascular reactivity to CO2 in the hypercapnic range was unchanged (5.5 ± 0.7 vs. 5.3 ± 0.7%/mmHg; P = 0.06), while it was lowered in the hypocapnic range (3.1 ± 0.7 vs. 1.9 ± 0.6%/mmHg; P < 0.05). Dynamic cerebral autoregulation was further reduced during sleep ( P < 0.05 vs. low altitude). Lowered cerebrovascular reactivity to CO2 and reduction in both dynamic cerebral autoregulation and MCAv during sleep at high altitude may be factors in the pathogenesis of breathing instability.
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Ruixing Y, Jiaqiang D, Dezhai Y, Weixiong L, Shangling P, Jinzhen W, Jiandong H, Xiuyan L. Effects of Demographic Characteristics, Health-Related Behaviors and Lifestyle Factors on the Prevalence of Hypertension for the Middle-Aged and Elderly in the Guangxi Hei Yi Zhuang and Han Populations. Kidney Blood Press Res 2006; 29:312-20. [PMID: 17106209 DOI: 10.1159/000097019] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2005] [Accepted: 09/08/2006] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND/AIMS Hei Yi (meaning black worship and black dress) Zhuang is the most conservative group among the 43 ethnic subgroups of Zhuang in China due to its unique culture and customs. The prevalence of hypertension in this population has not been well defined. Therefore, the present study was undertaken to compare the effects of the demographic characteristics, health-related behaviors and lifestyle factors on the prevalence of hypertension in the middle-aged and elderly of the Guangxi Hei Yi Zhuang and Han populations. METHODS A total of 657 people of Hei Yi Zhuang aged 40 and over were randomly selected from 7 villages in Napo County of China. Information on the demographic characteristics, health-related behaviors and lifestyle factors was collected by questionnaire. Blood pressure, height, weight, waist circumference, serum lipid and apolipoprotein levels were measured, and body mass index (BMI) was calculated as a measure of weight relative to height. The results were compared with those of 520 Han who live in the same district. RESULTS The prevalence of hypertension and isolated systolic hypertension in Hei Yi Zhuang was significantly higher than in Han (32.9 vs. 24.6%, p < 0.01, and 16.7 vs. 5.2%, p < 0.001, respectively). The systolic blood pressure levels and pulse pressure in Hei Yi Zhuang were also significantly higher than in Han (129 +/- 20.1 vs. 125.8 +/- 17.4 mm Hg, p < 0.01, and 51.5 +/- 16.1 vs. 47.1 +/- 12.0 mm Hg, p < 0.01, respectively). The prevalence of hypertension was positively correlated with triglycerides, male, age, and alcohol consumption in Hei Yi Zhuang, whereas it was positively correlated with total cholesterol, male, age, alcohol consumption and BMI in Han. The rates of awareness, treatment and control in Hei Yi Zhuang and Han are 7.9 vs. 19.5%, 4.2 vs. 13.3% and 1.4 vs. 9.4% (p < 0.01 for all), respectively. CONCLUSION The current study reveals a significant difference in the prevalence of hypertension, blood pressure levels, and the relative factors between the Hei Yi Zhuang and Han ethnic groups, which may have been due to differences in geographical characteristics, lifestyle, sodium intake, education levels, and even genetic factors.
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Affiliation(s)
- Yin Ruixing
- Department of Cardiology, Institute of Cardiovascular Diseases, First Affiliated Hospital, Guangxi Medical University, Nanning, China.
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Oltmanns KM, Gehring H, Rudolf S, Schultes B, Schweiger U, Born J, Fehm HL, Peters A. Persistent suppression of resting energy expenditure after acute hypoxia. Metabolism 2006; 55:669-75. [PMID: 16631445 DOI: 10.1016/j.metabol.2006.01.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2005] [Accepted: 01/08/2006] [Indexed: 11/28/2022]
Abstract
Resting energy expenditure (REE) is known to be influenced by various ambient conditions such as oxygen supply. Investigations in healthy subjects during acute hypoxia revealed a drop in REE, but persistent effects after hypoxia had ended have not been examined so far. Although indirect calorimetry is a well-established method to measure REE, it may lead to false conclusions when hyperventilation, rise in lactate or catecholamines, and decrease of food intake accompany hypoxia. Therefore, we determined REE in healthy men after hypoxia had ended and under conditions of controlled energy supply during a glucose clamp. In a double-blind crossover study design, we induced hypoxia for 30 minutes by decreasing oxygen saturation to 75% (vs 96% in a control session) in 13 healthy men. Indirect calorimetry was performed at baseline and 150 minutes after hypoxia had ended. Plasma glucose was held stable between 4.5 and 5.5 mmol/L, and lactate as well as catecholamine concentrations were monitored. In parallel, we measured alterations in hormones of the hypothalamic-pituitary-thyroid axis, which is one known factor mediating changes in REE. Resting energy expenditure was decreased after hypoxia (from 1656+/-80 to 1564+/-97 kcal/d) as compared with the normoxic control condition (1700+/-82 to 1749+/-79 kcal/d, P=.037), whereas the respiratory quotient remained stable (P=.79). Plasma lactate, catecholamine levels, and the pituitary thyroid secretory activity were unchanged after hypoxia (P>.2). Our data demonstrate that the REE decrease persists 150 minutes after acute hypoxia, indicating an adaptation of energy metabolism. This should be valued as an additive pathogenic factor in diseases with disturbed energy metabolism.
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Affiliation(s)
- Kerstin M Oltmanns
- Department of Psychiatry, University of Luebeck, 23538 Luebeck, Germany.
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Ainslie PN, Kolb JC, Ide K, Poulin MJ. Effect of five nights of normobaric hypoxia on cardiovascular responses to acute isocapnic hypoxia in humans: relationship to ventilatory chemosensitivity. ERGONOMICS 2005; 48:1523-34. [PMID: 16338718 DOI: 10.1080/00140130500101403] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
The aim of this study was to elucidate (1) the cardiovascular responses to acute isocapnic hypoxia stimuli following five nights of normobaric poikilocapnic hypoxia, and (2) whether the changes in the cardiovascular responses to hypoxia are correlated to the change in acute hypoxic ventilatory (AHVR) chemosensitivity. Twelve male subjects [26.6 +/- 4.1 (SD) years] slept 8-9 h day(-1) overnight for five consecutive days at a simulated altitude of 4300 m (FiO2 = approximately 13.8%). Using the technique of dynamic end-tidal forcing, the AHVR was assessed twice, prior to and immediately after the hypoxic exposure. During each AHVR test, mean arterial blood pressure (MAP) and heart rate (HR) were measured continuously using finger photoplethysmography and an ECG monitor, respectively. Immediately following the exposure, AHVR and MAP sensitivities were increased by 1.80 +/- 1.30 l min(-1) %(-1) (p < 0.01) and 0.69 +/- 0.40 mmHg %(-1) (p < 0.05), respectively, and there were significant correlations between the increases in the AHVR and MAP sensitivities (r = 0.67; p < 0.05). In summary, following five nights of normobaric hypoxia, there is an enhanced MAP response to hypoxic stimuli. The relationship between the enhanced AHVR and MAP sensitivity raises the possibility of a common pathway in the regulation of peripheral chemosensitivity and MAP responses during periods of isocapnic hypoxia.
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Affiliation(s)
- Philip N Ainslie
- Department of Physiology and Biophysics, University of Calgary, 3330 Hospital Drive NW, Calgary, Alberta, Canada T2N 4N1.
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Arslan S, Arslan N, Soylu A, Akgün C, Tepebasili I, Türkmen M, Kavukçu S. High altitude and blood pressure in children. THE YALE JOURNAL OF BIOLOGY AND MEDICINE 2004; 76:145-8. [PMID: 15482651 PMCID: PMC2582720 DOI: pmid/15482651] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
We aimed to evaluate the blood pressure of children who had similar demographic characteristics but lived at different altitudes. Blood pressure of the children attending primary schools in Izmir (sea level: n = 425) and Van (altitude: 1725 m, n = 291) were measured by mercurial sphygmomanometer for this study. They were similar with respect to age, sex, weight, height, and BMI. Mean age of the children was 10.51 +/- 0.87 years (range: 9 to 12 years), and 358 (50 percent) of them were female. Mean systolic blood pressure was significantly higher in the children living in Van than in the children living in Izmir (104.72 +/- 11.2 vs. 97.96 +/- 25.5 mmHg, respectively, p < .001). Similarly mean diastolic blood pressure was significantly higher in the children living in Van than in the children living in Izmir (63.98 +/- 9.3 vs. 59.91 +/- 10.0 mmHg, respectively, p < .001). When blood pressure was evaluated with regard to height percentile, the number of children with a blood pressure over 90 percentile were 19 (4.5 percent) and 48 (16.5 percent) for systolic blood pressure, and 25 (5.9 percent) and 37 (12.7 percent) for diastolic blood pressure among the children living in Izmir and Van, respectively (p < .001). Systolic and diastolic blood pressures were found to increase in parallel to the increase in body mass index in children living in Van (r = 0.358, p < .001 and r = 0.235, p < .001, respectively). However, blood pressures were not correlated to body mass index in children living in Izmir. A difference of 1700 m in altitude was associated with higher systolic and diastolic blood pressure levels in children with similar demographic characteristics, and at this altitude, body mass index and blood pressure showed a positive correlation.
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Affiliation(s)
- Sükrü Arslan
- Department of Pediatrics, Yüzüncü Yil University, Faculty of Medicine, Van, Turkey
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Sarkar S, Banerjee PK, Selvamurthy W. High altitude hypoxia: an intricate interplay of oxygen responsive macroevents and micromolecules. Mol Cell Biochem 2004; 253:287-305. [PMID: 14619980 DOI: 10.1023/a:1026080320034] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Physiological responses to high altitude hypoxia are complex and involve a range of mechanisms some of which occur within minutes of oxygen deprivation while others reset a cascade of biosynthetic and physiological programs within the cellular milieu. The O2 sensitive events occur at various organisational levels in the body: at the level of organism through an increase in alveolar ventilation involving interaction of chemoreceptors, the respiratory control centers in the medulla and the respiratory muscles and the lung/chest wall systems; at tissue level through the pulmonary vascular smooth muscle constriction and coronary and cerebral vessel vasodilation leading to optimized blood flow to tissues; at cellular level through release of neurotransmitters by the glomus cells of the carotid body, secretion of erythropoietin hormone by kidney and liver cells and release of vascular growth factors by parenchymal cells in many tissues; at molecular level there is expression/activation of an array of genes redirecting the metabolic and other cellular mechanisms to achieve enhanced cell survival under hypoxic environment. Transactivation of various oxygen responsive genes is regulated by the activation of various transcriptional factors which results in expression of genes in a highly coordinated manner. There is thus an intricate cascading interplay of biochemical pathways in response to hypoxia, which causes changes at the physiological and molecular levels. Added to this interplay is the possibility of genetic polymorphism and protein changes to adapt to environmental influences, which may allow a variability in the activity of the pathway. Our understanding of these interactions is growing and one may be close to the precise combination of genetic factors and protein factors that underlie the mechanism of what goes on under high altitude hypoxic stress and who will cope at high altitude.
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Affiliation(s)
- S Sarkar
- Division of Molecular Biology, Defence Institute of Physiology and Allied Sciences, Lucknow Road, Delhi, India.
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Oltmanns KM, Gehring H, Rudolf S, Schultes B, Rook S, Schweiger U, Born J, Fehm HL, Peters A. Hypoxia causes glucose intolerance in humans. Am J Respir Crit Care Med 2004; 169:1231-7. [PMID: 15044204 DOI: 10.1164/rccm.200308-1200oc] [Citation(s) in RCA: 156] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Hypoxic respiratory diseases are frequently accompanied by glucose intolerance. We examined whether hypoxia is a cause of glucose intolerance in healthy subjects. In a double-blind within-subject crossover design, hypoxic versus normoxic conditions were induced in 14 healthy men for 30 minutes by decreasing oxygen saturation to 75% (versus 96% in control subjects) under the conditions of a euglycemic clamp. The rate of dextrose infusion needed to maintain stable blood glucose levels was monitored. Neurohormonal stress response was evaluated by measuring catecholamine and cortisol concentrations as well as cardiovascular parameters, and symptoms of anxiety. To differentiate between the effects of stress hormonal response, and hypoxia itself, on glucose intolerance, we performed hypoglycemic clamps as a nonspecific control. We found a significant decrease in dextrose infusion rate over a period of 150 minutes after the start of hypoxia (p < 0.01). Hypoxia also increased plasma epinephrine concentration (p < 0.01), heart rate (p < 0.01), and symptoms of anxiety (p < 0.05), whereas the other parameters remained unaffected. Glucose intolerance was closely comparable between hypoxic and hypoglycemic conditions (p < 0.9) despite clear differences in stress hormonal responses. Hypoxia acutely causes glucose intolerance. One of the factors mediating this effect could be an elevated release of epinephrine.
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Affiliation(s)
- Kerstin M Oltmanns
- Department of Internal Medicine I, University of Luebeck, Luebeck, Germany.
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Abstract
Chronic hypoxia is associated with elevated sympathetic activity and hypertension in patients with chronic pulmonary obstructive disease. However, the effect of chronic hypoxia on systemic and regional sympathetic activity in healthy humans remains unknown. To determine if chronic hypoxia in healthy humans is associated with hyperactivity of the sympathetic system, we measured intra-arterial blood pressure, arterial blood gases, systemic and skeletal muscle noradrenaline (norepinephrine) spillover and vascular conductances in nine Danish lowlanders at sea level and after 9 weeks of exposure at 5260 m. Mean blood pressure was 28 % higher at altitude (P < 0.01) due to increases in both systolic (18 % higher, P < 0.05) and diastolic (41 % higher, P < 0.001) blood pressures. Cardiac output and leg blood flow were not altered by chronic hypoxia, but systemic vascular conductance was reduced by 30 % (P < 0.05). Plasma arterial noradrenaline (NA) and adrenaline concentrations were 3.7- and 2.4-fold higher at altitude, respectively (P < 0.05). The elevation of plasma arterial NA concentration was caused by a 3.8-fold higher whole-body NA release (P < 0.001) since whole-body noradrenaline clearance was similar in both conditions. Leg NA spillover was increased similarly (x 3.2, P < 0.05). These changes occurred despite the fact that systemic O2 delivery was greater after altitude acclimatisation than at sea level, due to 37 % higher blood haemoglobin concentration. In summary, this study shows that chronic hypoxia causes marked activation of the sympathetic nervous system in healthy humans and increased systemic arterial pressure, despite normalisation of the arterial O2 content with acclimatisation.
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