1
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Zhao B, Liu C, Qi Y, Zhang T, Wang Y, He X, Wang L, Jin T. Preliminary study of identified novel susceptibility loci for HAPE risk in a Chinese male Han population. Per Med 2024:1-15. [PMID: 38940394 DOI: 10.1080/17410541.2024.2365617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Accepted: 06/05/2024] [Indexed: 06/29/2024]
Abstract
High altitude pulmonary edema (HAPE) is a life-threatening form of non-cardiogenic pulmonary edema. In recent years, association studies have become the main method for identifying HAPE genetic loci. A genome-wide association study (GWAS) of HAPE risk-associated loci was performed in Chinese male Han individuals (164 HAPE cases and 189 healthy controls) by the Precision Medicine Diversity Array Chip with 2,771,835 loci (Applied Biosystems Axiom™). Eight overlapping candidate loci in CCNG2, RP11-445O3.2, NUPL1 and WWOX were finally selected. In silico functional analyses displayed the PPI network, functional enrichment and signal pathways related to CCNG2, NUPL1, WWOX and NRXN1. This study provides data supplements for HAPE susceptibility gene loci and new insights into HAPE susceptibility.
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Affiliation(s)
- Beibei Zhao
- School of Medicine, Xizang Minzu University, Xianyang 712082, Shaanxi, China
| | - Changchun Liu
- School of Medicine, Xizang Minzu University, Xianyang 712082, Shaanxi, China
| | - Yijin Qi
- School of Medicine, Xizang Minzu University, Xianyang 712082, Shaanxi, China
| | - Tianyi Zhang
- School of Medicine, Xizang Minzu University, Xianyang 712082, Shaanxi, China
| | - Yuhe Wang
- Department of Clinical Laboratory, The Affiliated Hospital of Xizang Minzu University, Xianyang, Shaanxi 712082, China
| | - Xue He
- School of Medicine, Xizang Minzu University, Xianyang 712082, Shaanxi, China
| | - Li Wang
- School of Medicine, Xizang Minzu University, Xianyang 712082, Shaanxi, China
| | - Tianbo Jin
- School of Medicine, Xizang Minzu University, Xianyang 712082, Shaanxi, China
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2
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Burtscher J, Raberin A, Brocherie F, Malatesta D, Manferdelli G, Citherlet T, Krumm B, Bourdillon N, Antero J, Rasica L, Burtscher M, Millet GP. Recommendations for Women in Mountain Sports and Hypoxia Training/Conditioning. Sports Med 2024; 54:795-811. [PMID: 38082199 PMCID: PMC11052836 DOI: 10.1007/s40279-023-01970-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/06/2023] [Indexed: 04/28/2024]
Abstract
The (patho-)physiological responses to hypoxia are highly heterogeneous between individuals. In this review, we focused on the roles of sex differences, which emerge as important factors in the regulation of the body's reaction to hypoxia. Several aspects should be considered for future research on hypoxia-related sex differences, particularly altitude training and clinical applications of hypoxia, as these will affect the selection of the optimal dose regarding safety and efficiency. There are several implications, but there are no practical recommendations if/how women should behave differently from men to optimise the benefits or minimise the risks of these hypoxia-related practices. Here, we evaluate the scarce scientific evidence of distinct (patho)physiological responses and adaptations to high altitude/hypoxia, biomechanical/anatomical differences in uphill/downhill locomotion, which is highly relevant for exercising in mountainous environments, and potentially differential effects of altitude training in women. Based on these factors, we derive sex-specific recommendations for mountain sports and intermittent hypoxia conditioning: (1) Although higher vulnerabilities of women to acute mountain sickness have not been unambiguously shown, sex-dependent physiological reactions to hypoxia may contribute to an increased acute mountain sickness vulnerability in some women. Adequate acclimatisation, slow ascent speed and/or preventive medication (e.g. acetazolamide) are solutions. (2) Targeted training of the respiratory musculature could be a valuable preparation for altitude training in women. (3) Sex hormones influence hypoxia responses and hormonal-cycle and/or menstrual-cycle phases therefore may be factors in acclimatisation to altitude and efficiency of altitude training. As many of the recommendations or observations of the present work remain partly speculative, we join previous calls for further quality research on female athletes in sports to be extended to the field of altitude and hypoxia.
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Affiliation(s)
- Johannes Burtscher
- Institute of Sport Sciences, Faculty of Biology and Medicine, University of Lausanne, Building Synathlon, Campus Dorigny, 1015, Lausanne, Switzerland
| | - Antoine Raberin
- Institute of Sport Sciences, Faculty of Biology and Medicine, University of Lausanne, Building Synathlon, Campus Dorigny, 1015, Lausanne, Switzerland
| | - Franck Brocherie
- Laboratory Sport, Expertise and Performance (EA 7370), French Institute of Sport, Paris, France
| | - Davide Malatesta
- Institute of Sport Sciences, Faculty of Biology and Medicine, University of Lausanne, Building Synathlon, Campus Dorigny, 1015, Lausanne, Switzerland
| | - Giorgio Manferdelli
- Institute of Sport Sciences, Faculty of Biology and Medicine, University of Lausanne, Building Synathlon, Campus Dorigny, 1015, Lausanne, Switzerland
| | - Tom Citherlet
- Institute of Sport Sciences, Faculty of Biology and Medicine, University of Lausanne, Building Synathlon, Campus Dorigny, 1015, Lausanne, Switzerland
| | - Bastien Krumm
- Institute of Sport Sciences, Faculty of Biology and Medicine, University of Lausanne, Building Synathlon, Campus Dorigny, 1015, Lausanne, Switzerland
| | - Nicolas Bourdillon
- Institute of Sport Sciences, Faculty of Biology and Medicine, University of Lausanne, Building Synathlon, Campus Dorigny, 1015, Lausanne, Switzerland
| | - Juliana Antero
- Institut de Recherche Bio-Médicale Et d'Épidémiologie du Sport (EA 7329), French Institute of Sport, Paris, France
| | - Letizia Rasica
- Faculty of Kinesiology, University of Calgary, Calgary, AB, Canada
| | - Martin Burtscher
- Department of Sport Science, University of Innsbruck, Innsbruck, Austria
| | - Grégoire P Millet
- Institute of Sport Sciences, Faculty of Biology and Medicine, University of Lausanne, Building Synathlon, Campus Dorigny, 1015, Lausanne, Switzerland.
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3
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Roche J, Rasmussen P, Gatterer H, Roveri G, Turner R, van Hall G, Maillard M, Walzl A, Kob M, Strapazzon G, Goetze JP, Schäfer ST, Kammerer T, Nader E, Connes P, Robert M, Mueller T, Feraille E, Siebenmann C. Hypoxia briefly increases diuresis but reduces plasma volume by fluid redistribution in women. Am J Physiol Heart Circ Physiol 2022; 323:H1068-H1079. [PMID: 36269645 PMCID: PMC9678412 DOI: 10.1152/ajpheart.00394.2022] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
We have recently reported that hypobaric hypoxia (HH) reduces plasma volume (PV) in men by decreasing total circulating plasma protein (TCPP). Here, we investigated whether this applies to women and whether an inflammatory response and/or endothelial glycocalyx shedding could facilitate the TCCP reduction. We further investigated whether acute HH induces a short-lived diuretic response that was overlooked in our recent study, where only 24-h urine volumes were evaluated. In a strictly controlled crossover protocol, 12 women underwent two 4-day sojourns in a hypobaric chamber: one in normoxia (NX) and one in HH equivalent to 3,500-m altitude. PV, urine output, TCPP, and markers for inflammation and glycocalyx shedding were repeatedly measured. Total body water (TBW) was determined pre- and postsojourns by deuterium dilution. PV was reduced after 12 h of HH and thereafter remained 230-330 mL lower than in NX (P < 0.0001). Urine flow was 45% higher in HH than in NX throughout the first 6 h (P = 0.01) but lower during the second half of the first day (P < 0.001). Twenty-four-hour urine volumes (P ≥ 0.37) and TBW (P ≥ 0.14) were not different between the sojourns. TCPP was lower in HH than in NX at the same time points as PV (P < 0.001), but inflammatory or glycocalyx shedding markers were not consistently increased. As in men, and despite initially increased diuresis, HH-induced PV contraction in women is driven by a loss of TCPP and ensuing fluid redistribution, rather than by fluid loss. The mechanism underlying the TCPP reduction remains unclear but does not seem to involve inflammation or glycocalyx shedding.NEW & NOTEWORTHY This study is the first to investigate the mechanisms underlying plasma volume (PV) contraction in response to hypoxia in women while strictly controlling for confounders. PV contraction in women has a similar time course and magnitude as in men and is driven by the same mechanism, namely, oncotically driven redistribution rather than loss of fluid. We further report that hypoxia facilitates an increase in diuresis, that is, however, short-lived and of little relevance for PV regulation.
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Affiliation(s)
- Johanna Roche
- 1Institute of Mountain Emergency Medicine, Eurac Research, Bolzano, Italy
| | | | - Hannes Gatterer
- 1Institute of Mountain Emergency Medicine, Eurac Research, Bolzano, Italy
| | - Giulia Roveri
- 1Institute of Mountain Emergency Medicine, Eurac Research, Bolzano, Italy
| | - Rachel Turner
- 1Institute of Mountain Emergency Medicine, Eurac Research, Bolzano, Italy
| | - Gerrit van Hall
- 3Department of Clinical Biochemistry, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark,4Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark,5Clinical Metabolomics Core Facility, Rigshospitalet, University of Copenhagen, Denmark
| | - Marc Maillard
- 6Service of Nephrology, University Hospital of Lausanne, Lausanne, Switzerland
| | - Anna Walzl
- 7Department of Anesthesiology, LMU Klinikum, Ludwig-Maximilians-University München, Munich, Germany
| | - Michael Kob
- 8Division of Clinical Nutrition, Bolzano Regional Hospital, Bolzano, Italy
| | - Giacomo Strapazzon
- 1Institute of Mountain Emergency Medicine, Eurac Research, Bolzano, Italy
| | - Jens Peter Goetze
- 3Department of Clinical Biochemistry, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Simon Thomas Schäfer
- 7Department of Anesthesiology, LMU Klinikum, Ludwig-Maximilians-University München, Munich, Germany
| | - Tobias Kammerer
- 7Department of Anesthesiology, LMU Klinikum, Ludwig-Maximilians-University München, Munich, Germany,9Department for Anesthesiology and Intensive Care Medicine, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Elie Nader
- 10Laboratory LIBM EA7424, Vascular Biology and Red Blood Cell Team, University of Lyon, Lyon, France
| | - Philippe Connes
- 10Laboratory LIBM EA7424, Vascular Biology and Red Blood Cell Team, University of Lyon, Lyon, France
| | - Mélanie Robert
- 10Laboratory LIBM EA7424, Vascular Biology and Red Blood Cell Team, University of Lyon, Lyon, France
| | - Thomas Mueller
- 11Department of Clinical Pathology, Hospital of Bolzano, Bolzano, Italy,12Department of Laboratory Medicine, Hospital Voecklabruck, Voecklabruck, Austria
| | - Eric Feraille
- 13National Center of Competence in Research Kidney Control of Homeostasis (Kidney.CH), Zurich, Switzerland,14Department of Cellular Physiology and Metabolism, University of Geneva, Geneva, Switzerland
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4
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Burtscher J, Mallet RT, Pialoux V, Millet GP, Burtscher M. Adaptive Responses to Hypoxia and/or Hyperoxia in Humans. Antioxid Redox Signal 2022; 37:887-912. [PMID: 35102747 DOI: 10.1089/ars.2021.0280] [Citation(s) in RCA: 52] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Significance: Oxygen is indispensable for aerobic life, but its utilization exposes cells and tissues to oxidative stress; thus, tight regulation of cellular, tissue, and systemic oxygen concentrations is crucial. Here, we review the current understanding of how the human organism (mal-)adapts to low (hypoxia) and high (hyperoxia) oxygen levels and how these adaptations may be harnessed as therapeutic or performance enhancing strategies at the systemic level. Recent Advances: Hyperbaric oxygen therapy is already a cornerstone of modern medicine, and the application of mild hypoxia, that is, hypoxia conditioning (HC), to strengthen the resilience of organs or the whole body to severe hypoxic insults is an important preparation for high-altitude sojourns or to protect the cardiovascular system from hypoxic/ischemic damage. Many other applications of adaptations to hypo- and/or hyperoxia are only just emerging. HC-sometimes in combination with hyperoxic interventions-is gaining traction for the treatment of chronic diseases, including numerous neurological disorders, and for performance enhancement. Critical Issues: The dose- and intensity-dependent effects of varying oxygen concentrations render hypoxia- and/or hyperoxia-based interventions potentially highly beneficial, yet hazardous, although the risks versus benefits are as yet ill-defined. Future Directions: The field of low and high oxygen conditioning is expanding rapidly, and novel applications are increasingly recognized, for example, the modulation of aging processes, mood disorders, or metabolic diseases. To advance hypoxia/hyperoxia conditioning to clinical applications, more research on the effects of the intensity, duration, and frequency of altered oxygen concentrations, as well as on individual vulnerabilities to such interventions, is paramount. Antioxid. Redox Signal. 37, 887-912.
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Affiliation(s)
- Johannes Burtscher
- Department of Biomedical Sciences, University of Lausanne, Lausanne, Switzerland.,Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland
| | - Robert T Mallet
- Department of Physiology and Anatomy, University of North Texas Health Science Center, Fort Worth, Texas, USA
| | - Vincent Pialoux
- Inter-University Laboratory of Human Movement Biology EA7424, University Claude Bernard Lyon 1, University of Lyon, Lyon, France
| | - Grégoire P Millet
- Department of Biomedical Sciences, University of Lausanne, Lausanne, Switzerland.,Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland
| | - Martin Burtscher
- Department of Sport Science, University of Innsbruck, Innsbruck, Austria
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5
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Williams AM, Levine BD, Stembridge M. A change of heart: mechanisms of cardiac adaptation to acute and chronic hypoxia. J Physiol 2022; 600:4089-4104. [PMID: 35930370 PMCID: PMC9544656 DOI: 10.1113/jp281724] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Accepted: 07/21/2022] [Indexed: 11/20/2022] Open
Abstract
Over the last 100 years, high‐altitude researchers have amassed a comprehensive understanding of the global cardiac responses to acute, prolonged and lifelong hypoxia. When lowlanders are exposed to hypoxia, the drop in arterial oxygen content demands an increase in cardiac output, which is facilitated by an elevated heart rate at the same time as ventricular volumes are maintained. As exposure is prolonged, haemoconcentration restores arterial oxygen content, whereas left ventricular filling and stroke volume are lowered as a result of a combination of reduced blood volume and hypoxic pulmonary vasoconstriction. Populations native to high‐altitude, such as the Sherpa in Asia, exhibit unique lifelong or generational adaptations to hypoxia. For example, they have smaller left ventricular volumes compared to lowlanders despite having larger total blood volume. More recent investigations have begun to explore the mechanisms underlying such adaptive responses by combining novel imaging techniques with interventions that manipulate cardiac preload, afterload, and/or contractility. This work has revealed the contributions and interactions of (i) plasma volume constriction; (ii) sympathoexcitation; and (iii) hypoxic pulmonary vasoconstriction with respect to altering cardiac loading, or otherwise preserving or enhancing biventricular systolic and diastolic function even amongst high altitude natives with excessive erythrocytosis. Despite these advances, various areas of investigation remain understudied, including potential sex‐related differences in response to high altitude. Collectively, the available evidence supports the conclusion that the human heart successfully adapts to hypoxia over the short‐ and long‐term, without signs of myocardial dysfunction in healthy humans, except in very rare cases of maladaptation.
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Affiliation(s)
- Alexandra M Williams
- Department of Cellular and Physiological Sciences, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada.,International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, BC, Canada
| | - Benjamin D Levine
- Institute for Exercise and Environmental Medicine, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Mike Stembridge
- Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, UK
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6
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Ryan BJ, Charkoudian N, McClung JP. Consider iron status when making sex comparisons in human physiology. J Appl Physiol (1985) 2021; 132:699-702. [PMID: 34792406 DOI: 10.1152/japplphysiol.00582.2021] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Affiliation(s)
- Benjamin J Ryan
- Thermal and Mountain Medicine Division, US Army Research Institute of Environmental Medicine, Natick, MA, United States
| | - Nisha Charkoudian
- Thermal and Mountain Medicine Division, US Army Research Institute of Environmental Medicine, Natick, MA, United States
| | - James P McClung
- Military Nutrition Division, US Army Research Institute of Environmental Medicine, Natick, MA, United States
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7
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Pulmonary Hypertension in Acute and Chronic High Altitude Maladaptation Disorders. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph18041692. [PMID: 33578749 PMCID: PMC7916528 DOI: 10.3390/ijerph18041692] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 02/05/2021] [Accepted: 02/07/2021] [Indexed: 12/13/2022]
Abstract
Alveolar hypoxia is the most prominent feature of high altitude environment with well-known consequences for the cardio-pulmonary system, including development of pulmonary hypertension. Pulmonary hypertension due to an exaggerated hypoxic pulmonary vasoconstriction contributes to high altitude pulmonary edema (HAPE), a life-threatening disorder, occurring at high altitudes in non-acclimatized healthy individuals. Despite a strong physiologic rationale for using vasodilators for prevention and treatment of HAPE, no systematic studies of their efficacy have been conducted to date. Calcium-channel blockers are currently recommended for drug prophylaxis in high-risk individuals with a clear history of recurrent HAPE based on the extensive clinical experience with nifedipine in HAPE prevention in susceptible individuals. Chronic exposure to hypoxia induces pulmonary vascular remodeling and development of pulmonary hypertension, which places an increased pressure load on the right ventricle leading to right heart failure. Further, pulmonary hypertension along with excessive erythrocytosis may complicate chronic mountain sickness, another high altitude maladaptation disorder. Importantly, other causes than hypoxia may potentially underlie and/or contribute to pulmonary hypertension at high altitude, such as chronic heart and lung diseases, thrombotic or embolic diseases. Extensive clinical experience with drugs in patients with pulmonary arterial hypertension suggests their potential for treatment of high altitude pulmonary hypertension. Small studies have demonstrated their efficacy in reducing pulmonary artery pressure in high altitude residents. However, no drugs have been approved to date for the therapy of chronic high altitude pulmonary hypertension. This work provides a literature review on the role of pulmonary hypertension in the pathogenesis of acute and chronic high altitude maladaptation disorders and summarizes current knowledge regarding potential treatment options.
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8
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Khurana VG, Jithoo R, Barnett M. Aerospace Implications of Key Neurological Conditions. Aerosp Med Hum Perform 2021; 92:113-119. [PMID: 33468292 DOI: 10.3357/amhp.5744.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
INTRODUCTION: The neurological impact (or lack thereof) of certain medical histories and imaging findings is important to understand in the context of air and spaceflight. There are a number of neurological conditions that, if present in pilots and astronauts, carry variable (and sometimes adverse) functional implications for safety and overall mission success. In this systematic overview, the authors will refer to the relevant clinical and radiological features of brain tumors and vascular anomalies, cerebral edema and intracranial hypertension, concussion and the traumatic brain injury (TBI) spectrum, hematomas, cerebrospinal fluid circulation anomalies including hydrocephalus and sequestrations, spinal degenerative changes, and cerebral ischemia and demyelination. It is notable that these last two conditions have recently been reported to be a complication in some people with coronavirus disease 2019 (COVID-19). A paradigm for practical neurological workup of symptomatic pilots and astronauts will be discussed, as will the controversial notion of pre-emptive radiological screening (vs. not screening) in asymptomatic or clinically occult situations. The concepts of medical surveillance in the setting of known or diagnosed pathologies, and expert panel review and simulator and flight checks in complex neurological cases, are also elaborated on in this paper. We believe this overview will contribute toward the enhancement of a broad understanding of neurological conditions, their clinical workup, and their precautionary management in the setting of aviation and aerospace.Khurana VG, Jithoo R, Barnett M. Aerospace implications of key neurological conditions. Aerosp Med Hum Perform. 2021; 92(2):113119.
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9
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Limmer M, de Marées M, Platen P. Alterations in acid-base balance and high-intensity exercise performance after short-term and long-term exposure to acute normobaric hypoxic conditions. Sci Rep 2020; 10:13732. [PMID: 32792614 PMCID: PMC7426914 DOI: 10.1038/s41598-020-70762-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Accepted: 08/04/2020] [Indexed: 11/21/2022] Open
Abstract
This investigation assessed the course of renal compensation of hypoxia-induced respiratory alkalosis by elimination of bicarbonate ions and impairments in anaerobic exercise after different durations of hypoxic exposure. Study A: 16 participants underwent a resting 12-h exposure to normobaric hypoxia (3,000 m). Blood gas analysis was assessed hourly. While blood pH was significantly increased, PO2, PCO2, and SaO2 were decreased within the first hour of hypoxia, and changes remained consistent. A substantial reduction in [HCO3-] levels was observed after 12 h of hypoxic exposure (- 1.35 ± 0.29 mmol/L, p ≤ 0.05). Study B: 24 participants performed in a randomized, cross-over trial portable tethered sprint running (PTSR) tests under normoxia and after either 1 h (n = 12) or 12 h (n = 12) of normobaric hypoxia (3,000 m). No differences occurred for PTSR-related performance parameters, but the reduction in blood lactate levels was greater after 12 h compared with 1 h (- 1.9 ± 2.2 vs 0.0 ± 2.3 mmol/L, p ≤ 0.05). These results indicate uncompensated respiratory alkalosis after 12 h of hypoxia and similar impairment of high-intensity exercise after 1 and 12 h of hypoxic exposure, despite a greater reduction in blood lactate responses after 12 h compared with 1 h of hypoxic exposure.
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Affiliation(s)
- Mirjam Limmer
- Institute of Sports Medicine and Sports Nutrition, Ruhr-University Bochum, Bochum, Germany.
- Institute of Outdoor Sports and Environmental Science, German Sports University Cologne, Cologne, Germany.
| | - Markus de Marées
- Institute of Sports Medicine and Sports Nutrition, Ruhr-University Bochum, Bochum, Germany
| | - Petra Platen
- Institute of Sports Medicine and Sports Nutrition, Ruhr-University Bochum, Bochum, Germany
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10
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Cheng HY, Croft QPP, Frise MC, Talbot NP, Petousi N, Robbins PA, Dorrington KL. Human hypoxic pulmonary vasoconstriction is unaltered by 8 h of preceding isocapnic hyperoxia. Physiol Rep 2018; 5:5/17/e13396. [PMID: 28899910 PMCID: PMC5599860 DOI: 10.14814/phy2.13396] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Revised: 07/28/2017] [Accepted: 07/31/2017] [Indexed: 12/27/2022] Open
Abstract
Exposure to sustained hypoxia of 8 h duration increases the sensitivity of the pulmonary vasculature to acute hypoxia, but it is not known whether exposure to sustained hyperoxia affects human pulmonary vascular control. We hypothesized that exposure to 8 h of hyperoxia would diminish the hypoxic pulmonary vasoconstriction (HPV) that occurs in response to a brief exposure to hypoxia. Eleven healthy volunteers were studied in a crossover protocol with randomization of order. Each volunteer was exposed to acute isocapnic hypoxia (end‐tidal PO2 = 50 mmHg for 10 min) before and after 8 h of hyperoxia (end‐tidal PO2 = 420 mmHg) or euoxia (end‐tidal PO2 = 100 mmHg). After at least 3 days, each volunteer returned and was exposed to the other condition. Systolic pulmonary artery pressure (an index of HPV) and cardiac output were measured, using Doppler echocardiography. Eight hours of hyperoxia had no effect on HPV or the response of cardiac output to acute hypoxia.
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Affiliation(s)
- Hung-Yuan Cheng
- Department of Physiology, Anatomy & Genetics, University of Oxford, Oxford, United Kingdom
| | - Quentin P P Croft
- Department of Physiology, Anatomy & Genetics, University of Oxford, Oxford, United Kingdom
| | - Matthew C Frise
- Department of Physiology, Anatomy & Genetics, University of Oxford, Oxford, United Kingdom
| | - Nick P Talbot
- Department of Physiology, Anatomy & Genetics, University of Oxford, Oxford, United Kingdom
| | - Nayia Petousi
- Department of Physiology, Anatomy & Genetics, University of Oxford, Oxford, United Kingdom
| | - Peter A Robbins
- Department of Physiology, Anatomy & Genetics, University of Oxford, Oxford, United Kingdom
| | - Keith L Dorrington
- Department of Physiology, Anatomy & Genetics, University of Oxford, Oxford, United Kingdom
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11
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Luks AM, Levett D, Martin DS, Goss CH, Mitchell K, Fernandez BO, Feelisch M, Grocott MP, Swenson ER. Changes in acute pulmonary vascular responsiveness to hypoxia during a progressive ascent to high altitude (5300 m). Exp Physiol 2017; 102:711-724. [PMID: 28390080 DOI: 10.1113/ep086083] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Accepted: 04/03/2017] [Indexed: 12/22/2022]
Abstract
NEW FINDINGS What is the central question of this study? Do the pulmonary vascular responses to hypoxia change during progressive exposure to high altitude and can alterations in these responses be related to changes in concentrations of circulating biomarkers that affect the pulmonary circulation? What is the main finding and its importance? In our field study with healthy volunteers, we demonstrate changes in pulmonary artery pressure suggestive of remodelling in the pulmonary circulation, but find no changes in the acute responsiveness of the pulmonary circulation to changes in oxygenation during 2 weeks of exposure to progressive hypoxia. Pulmonary artery pressure changes were associated with changes in erythropoietin, 8-isoprostane, nitrite and guanosine 3',5'-cyclic monophosphate. We sought to determine whether changes in pulmonary artery pressure responses to hypoxia suggestive of vascular remodelling occur during progressive exposure to high altitude and whether such alterations are related to changes in concentrations of circulating biomarkers with known or suspected actions on the pulmonary vasculature during ascent. We measured tricuspid valve transvalvular pressure gradients (TVPG) in healthy volunteers breathing air at sea level (London, UK) and in hypoxic conditions simulating the inspired O2 partial pressures at two locations in Nepal, Namche Bazaar (NB, elevation 3500 m) and Everest Base Camp (EBC, elevation 5300 m). During a subsequent 13 day trek, TVPG was measured at NB and EBC while volunteers breathed air and hyperoxic or hypoxic mixtures simulating the inspired O2 partial pressures at the other locations. For each location, we determined the slope of the relationship between TVPG and arterial oxygen saturation (SaO2) to estimate the pulmonary vascular response to hypoxia. Mean TVPG breathing air was higher at any SaO2 at EBC than at sea level or NB, but there was no change in the slope of the relationship between SaO2 and TVPG between locations. Nitric oxide availability remained unchanged despite increases in oxidative stress (elevated 8-isoprostane). Erythropoietin, pro-atrial natriuretic peptide and interleukin-18 levels progressively increased on ascent. Associations with TVPG were observed only with erythropoietin, 8-isoprostane, nitrite and guanosine 3',5'-cyclic monophosphate. Although the increased TVPG for any given SaO2 at EBC suggests that pulmonary vascular remodelling might occur during 2 weeks of progressive hypoxia, the lack of change in the slope of the relationship between TVPG and SaO2 indicates that the acute pulmonary vascular responsiveness to changes in oxygenation does not vary within this time frame.
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Affiliation(s)
- Andrew M Luks
- Department of Medicine, University of Washington, Seattle, WA, USA
| | - Denny Levett
- University College London Centre for Altitude Space and Extreme Environment Medicine, University College London Hospitals National Institute for Health Research (UCLH NIHR) Biomedical Research Centre, Institute of Sport and Exercise Health, London, UK.,Anaesthesia and Critical Care Research Unit, University Hospital Southampton National Health Service Foundation Trust, Southampton, UK.,Integrative Physiology and Critical Illness Group, Division of Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK.,Southampton National Institutes for Health Research (NIHR) Respiratory Biomedical Research Unit, Southampton, UK.,Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton General Hospital, Southampton, UK
| | - Daniel S Martin
- University College London Centre for Altitude Space and Extreme Environment Medicine, University College London Hospitals National Institute for Health Research (UCLH NIHR) Biomedical Research Centre, Institute of Sport and Exercise Health, London, UK
| | | | - Kay Mitchell
- University College London Centre for Altitude Space and Extreme Environment Medicine, University College London Hospitals National Institute for Health Research (UCLH NIHR) Biomedical Research Centre, Institute of Sport and Exercise Health, London, UK.,Anaesthesia and Critical Care Research Unit, University Hospital Southampton National Health Service Foundation Trust, Southampton, UK.,Integrative Physiology and Critical Illness Group, Division of Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK.,Southampton National Institutes for Health Research (NIHR) Respiratory Biomedical Research Unit, Southampton, UK.,Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton General Hospital, Southampton, UK
| | - Bernadette O Fernandez
- Integrative Physiology and Critical Illness Group, Division of Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK.,Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton General Hospital, Southampton, UK.,Warwick Medical School, University of Warwick, Coventry, UK
| | - Martin Feelisch
- Integrative Physiology and Critical Illness Group, Division of Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK.,Southampton National Institutes for Health Research (NIHR) Respiratory Biomedical Research Unit, Southampton, UK.,Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton General Hospital, Southampton, UK.,Warwick Medical School, University of Warwick, Coventry, UK
| | - Michael P Grocott
- University College London Centre for Altitude Space and Extreme Environment Medicine, University College London Hospitals National Institute for Health Research (UCLH NIHR) Biomedical Research Centre, Institute of Sport and Exercise Health, London, UK.,Anaesthesia and Critical Care Research Unit, University Hospital Southampton National Health Service Foundation Trust, Southampton, UK.,Integrative Physiology and Critical Illness Group, Division of Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK.,Southampton National Institutes for Health Research (NIHR) Respiratory Biomedical Research Unit, Southampton, UK.,Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton General Hospital, Southampton, UK
| | - Erik R Swenson
- Department of Medicine, University of Washington, Seattle, WA, USA.,Medical Service, Veterans Affairs (VA) Puget Sound Health Care System, Seattle, WA, USA
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12
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Giussani DA, Bennet L, Sferruzzi-Perri AN, Vaughan OR, Fowden AL. Hypoxia, fetal and neonatal physiology: 100 years on from Sir Joseph Barcroft. J Physiol 2016; 594:1105-11. [PMID: 26926314 DOI: 10.1113/jp272000] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Accepted: 12/11/2015] [Indexed: 12/15/2022] Open
Affiliation(s)
- D A Giussani
- Department of Physiology, Development & Neuroscience, University of Cambridge, Cambridge, CB2 3EG, UK
| | - L Bennet
- The Department of Physiology, University of Auckland, Auckland, New Zealand
| | - A N Sferruzzi-Perri
- Department of Physiology, Development & Neuroscience, University of Cambridge, Cambridge, CB2 3EG, UK
| | - O R Vaughan
- Department of Physiology, Development & Neuroscience, University of Cambridge, Cambridge, CB2 3EG, UK
| | - A L Fowden
- Department of Physiology, Development & Neuroscience, University of Cambridge, Cambridge, CB2 3EG, UK
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13
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The Effects of Sex on Cardiopulmonary Responses to Acute Normobaric Hypoxia. High Alt Med Biol 2016; 17:108-15. [DOI: 10.1089/ham.2015.0114] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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14
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Frise MC, Cheng HY, Nickol AH, Curtis MK, Pollard KA, Roberts DJ, Ratcliffe PJ, Dorrington KL, Robbins PA. Clinical iron deficiency disturbs normal human responses to hypoxia. J Clin Invest 2016; 126:2139-50. [PMID: 27140401 PMCID: PMC4887172 DOI: 10.1172/jci85715] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 03/10/2016] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Iron bioavailability has been identified as a factor that influences cellular hypoxia sensing, putatively via an action on the hypoxia-inducible factor (HIF) pathway. We therefore hypothesized that clinical iron deficiency would disturb integrated human responses to hypoxia. METHODS We performed a prospective, controlled, observational study of the effects of iron status on hypoxic pulmonary hypertension. Individuals with absolute iron deficiency (ID) and an iron-replete (IR) control group were exposed to two 6-hour periods of isocapnic hypoxia. The second hypoxic exposure was preceded by i.v. infusion of iron. Pulmonary artery systolic pressure (PASP) was serially assessed with Doppler echocardiography. RESULTS Thirteen ID individuals completed the study and were age- and sex-matched with controls. PASP did not differ by group or study day before each hypoxic exposure. During the first 6-hour hypoxic exposure, the rise in PASP was 6.2 mmHg greater in the ID group (absolute rises 16.1 and 10.7 mmHg, respectively; 95% CI for difference, 2.7-9.7 mmHg, P = 0.001). Intravenous iron attenuated the PASP rise in both groups; however, the effect was greater in ID participants than in controls (absolute reductions 11.1 and 6.8 mmHg, respectively; 95% CI for difference in change, -8.3 to -0.3 mmHg, P = 0.035). Serum erythropoietin responses to hypoxia also differed between groups. CONCLUSION Clinical iron deficiency disturbs normal responses to hypoxia, as evidenced by exaggerated hypoxic pulmonary hypertension that is reversed by subsequent iron administration. Disturbed hypoxia sensing and signaling provides a mechanism through which iron deficiency may be detrimental to human health. TRIAL REGISTRATION ClinicalTrials.gov (NCT01847352). FUNDING M.C. Frise is the recipient of a British Heart Foundation Clinical Research Training Fellowship (FS/14/48/30828). K.L. Dorrington is supported by the Dunhill Medical Trust (R178/1110). D.J. Roberts was supported by R&D funding from National Health Service (NHS) Blood and Transplant and a National Institute for Health Research (NIHR) Programme grant (RP-PG-0310-1004). This research was funded by the NIHR Oxford Biomedical Research Centre Programme.
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Affiliation(s)
- Matthew C. Frise
- University of Oxford, Department of Physiology, Anatomy and Genetics, Oxford, United Kingdom
| | - Hung-Yuan Cheng
- University of Oxford, Department of Physiology, Anatomy and Genetics, Oxford, United Kingdom
| | - Annabel H. Nickol
- Oxford University Hospitals NHS Foundation Trust, Oxford Centre for Respiratory Medicine, Churchill Hospital, Oxford, United Kingdom
| | - M. Kate Curtis
- University of Oxford, Department of Physiology, Anatomy and Genetics, Oxford, United Kingdom
| | - Karen A. Pollard
- University of Oxford, Department of Physiology, Anatomy and Genetics, Oxford, United Kingdom
| | - David J. Roberts
- University of Oxford, Nuffield Department of Clinical Laboratory Sciences, and National Health Service Blood and Transplant Oxford Centre, John Radcliffe Hospital, Oxford, United Kingdom
| | - Peter J. Ratcliffe
- University of Oxford, Nuffield Department of Medicine, Henry Wellcome Building for Molecular Physiology, Old Road Campus, Headington, Oxford, United Kingdom
| | - Keith L. Dorrington
- University of Oxford, Department of Physiology, Anatomy and Genetics, Oxford, United Kingdom
| | - Peter A. Robbins
- University of Oxford, Department of Physiology, Anatomy and Genetics, Oxford, United Kingdom
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15
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Balanos GM, Pugh K, Frise MC, Dorrington KL. Exaggerated pulmonary vascular response to acute hypoxia in older men. Exp Physiol 2015; 100:1187-98. [DOI: 10.1113/ep085403] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 08/03/2015] [Indexed: 12/16/2022]
Affiliation(s)
- George M. Balanos
- School of Sport, Exercise and Rehabilitation Sciences; University of Birmingham; Edgbaston Birmingham UK
| | - Keith Pugh
- School of Sport, Exercise and Rehabilitation Sciences; University of Birmingham; Edgbaston Birmingham UK
| | - Matthew C. Frise
- Department of Physiology, Anatomy & Genetics; University of Oxford; Oxford UK
| | - Keith L. Dorrington
- Department of Physiology, Anatomy & Genetics; University of Oxford; Oxford UK
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16
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Gokyo Khumbu/Ama Dablam Trek 2012: effects of physical training and high-altitude exposure on oxidative metabolism, muscle composition, and metabolic cost of walking in women. Eur J Appl Physiol 2015; 116:129-44. [PMID: 26349745 DOI: 10.1007/s00421-015-3256-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Accepted: 08/28/2015] [Indexed: 12/13/2022]
Abstract
PURPOSE We investigated the effects of moderate-intensity training at low and high altitude on VO2 and QaO2 kinetics and on myosin heavy-chain expression (MyHC) in seven women (36.3 yy ± 7.1; 65.8 kg ± 11.7; 165 cm ± 8) who participated in two 12- to 14-day trekking expeditions at low (598 m) and high altitude (4132 m) separated by 4 months of recovery. METHODS Breath-by-breath VO2 and beat-by-beat QaO2 at the onset of moderate-intensity cycling exercise and energy cost of walking (Cw) were assessed before and after trekking. MyHC expression of vastus lateralis was evaluated before and after low-altitude and after high-altitude trekking; muscle fiber high-resolution respirography was performed at the beginning of the study and after high-altitude trekking. RESULTS Mean response time of VO2 kinetics was faster (P = 0.002 and P = 0.001) and oxygen deficit was smaller (P = 0.001 and P = 0.0004) after low- and high-altitude trekking, whereas ˙ QaO2 kinetics and Cw did not change. Percentages of slow and fast isoforms of MyHC and mitochondrial mass were not affected by low- and high-altitude training. After training altitude, muscle fiber ADP-stimulated mitochondrial respiration was decreased as compared with the control condition (P = 0.016), whereas leak respiration was increased (P = 0.031), leading to a significant increase in the respiratory control ratio (P = 0.016). CONCLUSIONS Although training did not significantly modify muscle phenotype, it induced beneficial adaptations of the oxygen transport-utilization systems witnessed by faster VO2 kinetics at exercise onset.
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17
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Frise MC, Robbins PA. Iron, oxygen, and the pulmonary circulation. J Appl Physiol (1985) 2015; 119:1421-31. [PMID: 26066825 PMCID: PMC4683351 DOI: 10.1152/japplphysiol.00179.2015] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Accepted: 06/05/2015] [Indexed: 12/24/2022] Open
Abstract
The human pulmonary vasculature vasoconstricts in response to a reduction in alveolar oxygen tension, a phenomenon termed hypoxic pulmonary vasoconstriction (HPV). This review describes the time course of this behavior, which occurs in distinct phases, and then explores the importance for HPV of the hypoxia-inducible factor (HIF) pathway. Next, the HIF-hydroxylase enzymes that act as molecular oxygen sensors within the HIF pathway are discussed. These enzymes are particularly sensitive to intracellular iron availability, which confers iron-sensing properties on the HIF pathway. Human studies of iron chelation and supplementation are then reviewed. These demonstrate that the iron sensitivity of the HIF pathway evident from in vitro experiments is relevant to human pulmonary vascular physiology. Next, the importance of iron status in high-altitude illness and chronic cardiopulmonary disease is explored, and the therapeutic potential of intravenous iron discussed. The review concludes by highlighting some further complexities that arise from interactions between the HIF pathway and other intracellular iron-sensing mechanisms.
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Affiliation(s)
- Matthew C Frise
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Peter A Robbins
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
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