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Möller FN, Fan JL, Futral JE, Hodgman CF, Kayser B, Lovering AT. Cardiopulmonary haemodynamics in Tibetans and Han Chinese during rest and exercise. J Physiol 2024; 602:3893-3907. [PMID: 38924564 DOI: 10.1113/jp286303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Accepted: 05/22/2024] [Indexed: 06/28/2024] Open
Abstract
During sea-level exercise, blood flow through intrapulmonary arteriovenous anastomoses (IPAVA) in humans without a patent foramen ovale (PFO) is negatively correlated with pulmonary pressure. Yet, it is unknown whether the superior exercise capacity of Tibetans well adapted to living at high altitude is the result of lower pulmonary pressure during exercise in hypoxia, and whether their cardiopulmonary characteristics are significantly different from lowland natives of comparable ancestry (e.g. Han Chinese). We found a 47% PFO prevalence in male Tibetans (n = 19) and Han Chinese (n = 19) participants. In participants without a PFO (n = 10 each group), we measured heart structure and function at rest and peak oxygen uptake (V ̇ O 2 peak ${{\dot{V}}_{{{{\mathrm{O}}}_{\mathrm{2}}}{\mathrm{peak}}}}$ ), peak power output (W ̇ p e a k ${{\dot{W}}_{peak}}$ ), pulmonary artery systolic pressure (PASP), blood flow through IPAVA and cardiac output (Q ̇ T ${{\dot{Q}}_{\mathrm{T}}} $ ) at rest and during recumbent cycle ergometer exercise at 760 Torr (SL) and at 410 Torr (ALT) barometric pressure in a pressure chamber. Tibetans achieved a higherW peak ${W}_{\textit{peak}}$ than Han, and a higherV ̇ O 2 peak ${{\dot{V}}_{{{{\mathrm{O}}}_{\mathrm{2}}}{\mathrm{peak}}}}$ at ALT without differences in heart rate, stroke volume orQ ̇ T ${{\dot{Q}}_{\mathrm{T}}} $ . Blood flow through IPAVA was generally similar between groups. Increases in PASP and total pulmonary resistance at ALT were comparable between the groups. There were no differences in the slopes of PASP plotted as a function ofQ ̇ T ${{\dot{Q}}_{\mathrm{T}}} $ during exercise. In those without PFO, our data indicate that the superior aerobic exercise capacity of Tibetans over Han Chinese is independent of cardiopulmonary features and more probably linked to differences in local muscular oxygen extraction. KEY POINTS: Patent foramen ovale (PFO) prevalence was 47% in Tibetans and Han Chinese living at 2 275 m. Subjects with PFO were excluded from exercise studies. Compared to Han Chinese, Tibetans had a higher peak workload with acute compression to sea level barometric pressure (SL) and acute decompression to 5000 m altitude (ALT). Comprehensive cardiac structure and function at rest were not significantly different between Han Chinese and Tibetans. Tibetans and Han had similar blood flow through intrapulmonary arteriovenous anastomoses (IPAVA) during exercise at SL. Peak pulmonary artery systolic pressure (PASP) and total pulmonary resistance were different between SL and ALT, with significantly increased PASP for Han compared to Tibetans at ALT. No differences were observed between groups at acute SL and ALT.
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Affiliation(s)
- Fabian N Möller
- Department of Aeronautics and Astronautics, Massachusetts Institute of Technology, Boston, MA, USA
- Department of Human Physiology, University of Oregon, Eugene, OR, USA
- German Sport University Cologne, Institute for Professional Sport Education and Qualification, Cologne, Germany
| | - Jui-Lin Fan
- Department of Physiology, Manaaki Manawa - The Centre for Heart Research, University of Auckland, Faculty of Medical and Health Sciences, Auckland, New Zealand
| | - Joel E Futral
- Department of Human Physiology, University of Oregon, Eugene, OR, USA
- Oregon Heart & Vascular Institute, Springfield, Oregon, USA
| | - Charles F Hodgman
- Department of Health and Human Performance, University of Houston, Houston, TX, USA
| | - Bengt Kayser
- University of Lausanne, Institute of Sports Sciences, Lausanne, Switzerland
| | - Andrew T Lovering
- Department of Human Physiology, University of Oregon, Eugene, OR, USA
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Liu X, Tang J, Long W, Zou Y, Tan J. Comparison of physical activity and physical fitness in children and adolescents of Chinese Han and Tibet ethnicity. Front Public Health 2024; 12:1392803. [PMID: 38784594 PMCID: PMC11111887 DOI: 10.3389/fpubh.2024.1392803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Accepted: 04/23/2024] [Indexed: 05/25/2024] Open
Abstract
Background Physical activity (PA) and physical fitness (PF) are important markers of health status in children and adolescents in different ethnicities. In this study, we aimed to compare the PA and PF indicators between Tibetan and Han children and adolescents. Methods Children and adolescents of 4-9 grades were recruited in Shigatse (n = 963) and Shanghai (n = 2,525) respectively. The information related to demographic, PA, and PF was collected via a self-reported questionnaire. PA was assessed through the participation of moderate to vigorous PA (MVPA), muscle-strengthening exercise (MSE) and organized sport participation (OSP). PF was estimated using the International Fitness Scale containing components of overall fitness, cardiorespiratory fitness, speed and agility, muscular strength and flexibility. Results Han (mean age = 13.45 ± 3.3 years; 49.7% girls) and Tibet (mean age = 13.8 ± 2.5 years; 48.3% girls) children and adolescents from Shanghai and Shigatse completed the questionnaire survey. It was revealed that Tibetan students had higher MVPA, MSE and OSP than children and adolescents of Han ethnicity (p < 0.01, small to medium effect size). A relatively higher percentage of student in Shanghai did not participate in any form of PA. On the other hand, less Tibetan students thought their PF indicators including overall fitness, cardiorespiratory fitness, speed and agility, muscular strength and flexibility were poor or very poor than their counterparts of Han ethnicity (p < 0.01, small to medium effect size). Conclusion Tibetan children and adolescents have higher levels of PA and PF in comparison to their Han counterparts. More children and adolescents of Han ethnicity engage in no PA and think their PF indicators were poor.
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Affiliation(s)
- Xiaodi Liu
- School of Physical Science and Technology, Ningbo University, Ningbo, China
| | - Jiaxing Tang
- School of Physical Education, Shanghai University of Sport, Shanghai, China
| | - Weixuan Long
- Department of Sports Science, College of Education, Zhejiang University, Hangzhou, China
| | - Yu Zou
- Department of Sports Science, College of Education, Zhejiang University, Hangzhou, China
| | - Jingwang Tan
- Department of Sports Science, College of Education, Zhejiang University, Hangzhou, China
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3
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Garrett EJ, Prasad SK, Schweizer RM, McClelland GB, Scott GR. Evolved changes in phenotype across skeletal muscles in deer mice native to high altitude. Am J Physiol Regul Integr Comp Physiol 2024; 326:R297-R310. [PMID: 38372126 PMCID: PMC11283899 DOI: 10.1152/ajpregu.00206.2023] [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: 08/24/2023] [Revised: 01/11/2024] [Accepted: 02/09/2024] [Indexed: 02/20/2024]
Abstract
The cold and hypoxic conditions at high altitude necessitate high metabolic O2 demands to support thermogenesis while hypoxia reduces O2 availability. Skeletal muscles play key roles in thermogenesis, but our appreciation of muscle plasticity and adaptation at high altitude has been hindered by past emphasis on only a small number of muscles. We examined this issue in deer mice (Peromyscus maniculatus). Mice derived from both high-altitude and low-altitude populations were born and raised in captivity and then acclimated as adults to normoxia or hypobaric hypoxia (12 kPa O2 for 6-8 wk). Maximal activities of citrate synthase (CS), cytochrome c oxidase (COX), β-hydroxyacyl-CoA dehydrogenase (HOAD), hexokinase (HK), pyruvate kinase (PK), and lactate dehydrogenase (LDH) were measured in 20 muscles involved in shivering, locomotion, body posture, ventilation, and mastication. Principal components analysis revealed an overall difference in muscle phenotype between populations but no effect of hypoxia acclimation. High-altitude mice had greater activities of mitochondrial enzymes and/or lower activities of PK or LDH across many (but not all) respiratory, limb, core and mastication muscles compared with low-altitude mice. In contrast, chronic hypoxia had very few effects across muscles. Further examination of CS in the gastrocnemius showed that population differences in enzyme activity stemmed from differences in protein abundance and mRNA expression but not from population differences in CS amino acid sequence. Overall, our results suggest that evolved increases in oxidative capacity across many skeletal muscles, at least partially driven by differences in transcriptional regulation, may contribute to high-altitude adaptation in deer mice.NEW & NOTEWORTHY Most previous studies of muscle plasticity and adaptation in high-altitude environments have focused on a very limited number of skeletal muscles. Comparing high-altitude versus low-altitude populations of deer mice, we show that a large number of muscles involved in shivering, locomotion, body posture, ventilation, and mastication exhibit greater mitochondrial enzyme activities in the high-altitude population. Therefore, evolved increases in mitochondrial oxidative capacity across skeletal muscles contribute to high-altitude adaptation.
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Affiliation(s)
- Emily J Garrett
- Department of Biology, McMaster University, Hamilton, Ontario, Canada
| | - Srikripa K Prasad
- Department of Biology, McMaster University, Hamilton, Ontario, Canada
| | - Rena M Schweizer
- Division of Biological Sciences, University of Montana, Missoula, Montana, United States
- United States Department of Agriculture, Agricultural Research Service, Pollinating Insects Research Unit, Utah State University, Logan, Utah, United States
| | | | - Graham R Scott
- Department of Biology, McMaster University, Hamilton, Ontario, Canada
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Bi C, Lin H, Zhang J, Gui X, Shi Z. Regional variation in growth status: A cross-sectional survey among Tibetan adolescents living at three different high altitudes in Tibet, China. Am J Hum Biol 2022; 35:e23856. [PMID: 36579776 DOI: 10.1002/ajhb.23856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 12/14/2022] [Accepted: 12/15/2022] [Indexed: 12/30/2022] Open
Abstract
OBJECTIVE To explore the regional and age variation in growth status and age-by-site interaction effect on the growth status among Chinese Tibetan adolescents at different altitudes in Tibet, China. METHODS The research was conducted in three regions of Tibet, China: Nyingchi (average altitude 3100 m), Lhasa (average altitude 3650 m), and Nagqu (average altitude 4500 m). A total of 3817 Chinese Tibetan adolescents aged 12-18 years were tested for height, weight, chest circumference, and waist circumference. One-way ANOVA was used to compare the growth status of Chinese Tibetan adolescents. Two-way ANOVA was used to explore the age-by-site interaction effect on the growth status of Chinese Tibetan adolescents. RESULTS The height, weight, and chest circumference of Chinese Tibetan adolescents in Nagqu are the lowest among the three cities. Age and site have an interaction effect influence on the growth status of Chinese Tibetan adolescents (p < .01). CONCLUSIONS The growth indicators (height, weight, chest circumference, WC) of Chinese Tibetan adolescents differed with altitudes. Policies to improve the growth status of Chinese Tibetan adolescents in Nagqu are urgently needed.
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Affiliation(s)
- Cunjian Bi
- School of Physical Education, Chizhou University, Chizhou, China.,Sports Health Promotion Center, Chizhou University, Chizhou, China
| | - Hongniu Lin
- School of Physical Education, Chizhou University, Chizhou, China.,Sports Health Promotion Center, Chizhou University, Chizhou, China
| | - Jie Zhang
- School of Physical Education, Chizhou University, Chizhou, China.,Sports Health Promotion Center, Chizhou University, Chizhou, China
| | - Xiaoying Gui
- Lhasa Beijing Experimental Middle School Sports Group, Lhasa, China
| | - Zhen Shi
- Sports Department, Tibet University, Lhasa, China
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Ortiz-Prado E, Cordovez SP, Vasconez E, Viscor G, Roderick P. Chronic high-altitude exposure and the epidemiology of ischaemic stroke: a systematic review. BMJ Open 2022; 12:e051777. [PMID: 35487749 PMCID: PMC9058702 DOI: 10.1136/bmjopen-2021-051777] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
INTRODUCTION About 5.7% of the world population resides above 1500 m. It has been hypothesised that acute exposure to high-altitude locations can increase stroke risk, while chronic hypoxia can reduce stroke-related mortality. OBJECTIVE This review aims to provide an overview of the available evidence on the association between long-term high-altitude exposure and ischaemic stroke. DESIGN A systematic review was performed from 1 January 1960 to 1 December 2021 to assess the possible link between high-altitude exposure and ischaemic stroke. The AMED, EMBASE, Cochrane Library, PubMed, MEDLINE, the Europe PubMed Central and the Latin-American bibliographic database Scielo were accessed using the University of Southampton library tool Delphis. In this review, we included population and individual-based observational studies, including cross-sectional and longitudinal studies except for those merely descriptive individual-based case reports. Studies were limited to humans living or visiting high-altitude locations for at least 28 days as a cut-off point for chronic exposure. RESULTS We reviewed a total of 1890 abstracts retrieved during the first step of the literature review process. The authors acquired in full text as potentially relevant 204 studies. Only 17 documents met the inclusion criteria and were finally included. Ten studies clearly suggest that living at high altitudes may be associated with an increased risk of stroke; however, five studies suggest that altitude may act as a protective factor for the development of stroke, while two studies report ambiguous results. CONCLUSIONS This review suggests that the most robust studies are more likely to find that prolonged living at higher altitudes reduces the risk of developing stroke or dying from it. Increased irrigation due to angiogenesis and increased vascular perfusion might be the reason behind improved survival profiles among those living within this altitude range. In contrast, residing above 3500 m seems to be associated with an apparent increased risk of developing stroke, probably linked to the presence of polycythaemia and other associated factors such as increased blood viscosity.
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Affiliation(s)
- Esteban Ortiz-Prado
- One Health Research Group, Universidad de Las Américas, Quito, Ecuador
- Department of Cell Biology, Physiology and Immunology, Universitat de Barcelona, Barcelona, Spain
| | - Simone Pierina Cordovez
- One Health Research Group, Universidad de Las Américas, Quito, Ecuador
- Facultad de Medicina, Universidad San Gregorio de Portoviejo, Portoviejo, Manabi, Ecuador
| | - Eduardo Vasconez
- One Health Research Group, Universidad de Las Américas, Quito, Ecuador
| | - Ginés Viscor
- Department of Cell Biology, Physiology and Immunology, Universitat de Barcelona, Barcelona, Spain
| | - Paul Roderick
- Faculty of Medicine, University of Southampton, Southampton, UK
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Ortiz-Prado E, Portilla D, Mosquera-Moscoso J, Simbaña-Rivera K, Duta D, Ochoa I, Burgos G, Izquierdo-Condoy JS, Vásconez E, Calvopiña M, Viscor G. Hematological Parameters, Lipid Profile, and Cardiovascular Risk Analysis Among Genotype-Controlled Indigenous Kiwcha Men and Women Living at Low and High Altitudes. Front Physiol 2021; 12:749006. [PMID: 34759840 PMCID: PMC8573321 DOI: 10.3389/fphys.2021.749006] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Accepted: 09/21/2021] [Indexed: 01/29/2023] Open
Abstract
Introduction: Human adaptation to high altitude is due to characteristic adjustments at every physiological level. Differences in lipid profile and cardiovascular risk factors in altitude dwellers have been previously explored. Nevertheless, there are no reports available on genotype-controlled matches among different altitude-adapted indigenous populations. Objective: To explore the possible differences in plasma lipid profile and cardiovascular risk among autochthonous Kiwcha people inhabitants of low and high-altitude locations. Methodology: A cross-sectional analysis of plasmatic lipid profiles and cardiovascular risk factors in lowland Kiwchas from Limoncocha (230 m) and high-altitude Kiwchas from Oyacachi (3,800 m). Results: In the low altitude group, 66% were women (n = 78) and 34% (n = 40) were men, whereas in the high altitude group, 59% (n = 56) were women and 41% (n = 41%) were men. We found the proportion of overweight and obese individuals to be higher among low altitude dwellers (p < 0.05). Red blood cells (RBCs), hemoglobin concentration, and SpO2% were higher among high altitude dwellers and the erythrocyte size was found to be smaller at high altitude. The group located at low altitude also showed lower levels of plasma cholesterol, low-density lipoprotein (LDL), and high-density lipoprotein (HDL), but most of these differences are not influenced by gender or elevation. Conclusions: Living at an altitude elicits well-known adaptive physiological changes such as erythrocyte count, hemoglobin concentration, hematocrit level, and serum glucose level. We also report clinical differences in the plasma lipid profile, with higher levels of cholesterol, HDL, and LDL in inhabitants of the Andes Mountain vs. their Amazonian basin peers. Despite this, we did not find significant differences in cardiovascular risk.
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Affiliation(s)
- Esteban Ortiz-Prado
- One Health Research Group, Faculty of Medicine, Universidad de las Americas, Quito, Ecuador.,Department of Cell Biology, Physiology and Immunology, Universidad de Barcelona, Barcelona, Spain
| | - David Portilla
- One Health Research Group, Faculty of Medicine, Universidad de las Americas, Quito, Ecuador
| | | | | | - Diego Duta
- General Ward, Limoncocha Community Health Unit, Limoncocha, Ecuador
| | - Israel Ochoa
- General Ward, Oyacachi Community Health Unit, Oyacachi, Ecuador
| | - German Burgos
- Faculty of Medicine, Universidad de Las Americas, Quito, Ecuador
| | | | - Eduardo Vásconez
- One Health Research Group, Faculty of Medicine, Universidad de las Americas, Quito, Ecuador
| | - Manuel Calvopiña
- One Health Research Group, Faculty of Medicine, Universidad de las Americas, Quito, Ecuador
| | - Ginés Viscor
- Department of Cell Biology, Physiology and Immunology, Universidad de Barcelona, Barcelona, Spain
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7
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Ortiz-Prado E, Espinosa PS, Borrero A, Cordovez SP, Vasconez JE, Barreto-Grimales A, Coral-Almeida M, Henriquez-Trujillo AR, Simbaña-Rivera K, Gomez-Barreno L, Viscor G, Roderick P. Stroke-Related Mortality at Different Altitudes: A 17-Year Nationwide Population-Based Analysis From Ecuador. Front Physiol 2021; 12:733928. [PMID: 34675818 PMCID: PMC8525493 DOI: 10.3389/fphys.2021.733928] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 09/08/2021] [Indexed: 12/23/2022] Open
Abstract
Introduction: Worldwide, more than 5.7% of the population reside above 1,500 m of elevation. It has been hypothesized that acute short-term hypoxia exposure could increase the risk of developing a stroke. Studies assessing the effect of altitude on stroke have provided conflicting results, some analyses suggest that long-term chronic exposure could be associated with reduced mortality and lower stroke incidence rates. Methods: An ecological analysis of all stroke hospital admissions, mortality rates, and disability-adjusted life years in Ecuador was performed from 2001 to 2017. The cases and population at risk were categorized in low (<1,500 m), moderate (1,500–2,500 m), high (2,500–3,500 m), and very high altitude (3,500–5,500 m) according to the place of residence. The derived crude and direct standardized age-sex adjusted mortality and hospital admission rates were calculated. Results: A total of 38,201 deaths and 75,893 stroke-related hospital admissions were reported. High altitude populations (HAP) had lower stroke mortality in men [OR: 0.91 (0.88–0.95)] and women [OR: 0.83 (0.79–0.86)]. In addition, HAP had a significant lower risk of getting admitted to the hospital when compared with the low altitude group in men [OR: 0.55 (CI 95% 0.54–0.56)] and women [OR: 0.65 (CI 95% 0.64–0.66)]. Conclusion: This is the first epidemiological study that aims to elucidate the association between stroke and altitude using four different elevation ranges. Our findings suggest that living at higher elevations offers a reduction or the risk of dying due to stroke as well as a reduction in the probability of being admitted to the hospital. Nevertheless, this protective factor has a stronger effect between 2,000 and 3,500 m.
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Affiliation(s)
- Esteban Ortiz-Prado
- One Health Research Group, Faculty of Medicine, Universidad de Las Américas, Quito, Ecuador.,Departamento de Biología Celular, Fisiología e Inmunología, Universitat de Barcelona, Barcelona, Spain
| | - Patricio S Espinosa
- Neurology, Marcus Neuroscience Institute, Boca Raton Regional Hospital, Boca Raton, FL, United States
| | - Alfredo Borrero
- One Health Research Group, Faculty of Medicine, Universidad de Las Américas, Quito, Ecuador
| | - Simone P Cordovez
- One Health Research Group, Faculty of Medicine, Universidad de Las Américas, Quito, Ecuador
| | - Jorge E Vasconez
- One Health Research Group, Faculty of Medicine, Universidad de Las Américas, Quito, Ecuador
| | | | - Marco Coral-Almeida
- One Health Research Group, Faculty of Medicine, Universidad de Las Américas, Quito, Ecuador
| | | | | | - Lenin Gomez-Barreno
- One Health Research Group, Faculty of Medicine, Universidad de Las Américas, Quito, Ecuador
| | - Gines Viscor
- Departamento de Biología Celular, Fisiología e Inmunología, Universitat de Barcelona, Barcelona, Spain
| | - Paul Roderick
- Faculty of Medicine, School of Primary Care, Population Sciences and Medical Education, University of Southampton, Southampton, United Kingdom
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8
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Ivy CM, Prest H, West CM, Scott GR. Distinct Mechanisms Underlie Developmental Plasticity and Adult Acclimation of Thermogenic Capacity in High-Altitude Deer Mice. Front Physiol 2021; 12:718163. [PMID: 34456754 PMCID: PMC8385410 DOI: 10.3389/fphys.2021.718163] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 07/08/2021] [Indexed: 11/13/2022] Open
Abstract
Developmental plasticity can elicit phenotypic adjustments that help organisms cope with environmental change, but the relationship between developmental plasticity and plasticity in adult life (e.g., acclimation) remains unresolved. We sought to examine developmental plasticity and adult acclimation in response to hypoxia of aerobic capacity (V̇O2max) for thermogenesis in deer mice (Peromyscus maniculatus) native to high altitude. Deer mice were bred in captivity and exposed to normoxia or one of four hypoxia treatments (12 kPa O2) across life stages: adult hypoxia (6–8 weeks), post-natal hypoxia (birth to adulthood), life-long hypoxia (before conception to adulthood), and parental hypoxia (mice conceived and raised in normoxia, but parents previously exposed to hypoxia). Hypoxia during perinatal development increased V̇O2max by a much greater magnitude than adult hypoxia. The amplified effect of developmental hypoxia resulted from physiological plasticity that did not occur with adult hypoxia – namely, increases in lung ventilation and volume. Evolved characteristics of deer mice enabled developmental plasticity, because white-footed mice (P. leucopus; a congener restricted to low altitudes) could not raise pups in hypoxia. Parental hypoxia had no persistent effects on V̇O2max. Therefore, developmental plasticity can have much stronger phenotypic effects and can manifest from distinct physiological mechanisms from adult acclimation.
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Affiliation(s)
- Catherine M Ivy
- Department of Biology, McMaster University, Hamilton, ON, Canada
| | - Haley Prest
- Department of Biology, McMaster University, Hamilton, ON, Canada
| | - Claire M West
- Department of Biology, McMaster University, Hamilton, ON, Canada
| | - Graham R Scott
- Department of Biology, McMaster University, Hamilton, ON, Canada
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9
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Storz JF. High-Altitude Adaptation: Mechanistic Insights from Integrated Genomics and Physiology. Mol Biol Evol 2021; 38:2677-2691. [PMID: 33751123 PMCID: PMC8233491 DOI: 10.1093/molbev/msab064] [Citation(s) in RCA: 56] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Population genomic analyses of high-altitude humans and other vertebrates have identified numerous candidate genes for hypoxia adaptation, and the physiological pathways implicated by such analyses suggest testable hypotheses about underlying mechanisms. Studies of highland natives that integrate genomic data with experimental measures of physiological performance capacities and subordinate traits are revealing associations between genotypes (e.g., hypoxia-inducible factor gene variants) and hypoxia-responsive phenotypes. The subsequent search for causal mechanisms is complicated by the fact that observed genotypic associations with hypoxia-induced phenotypes may reflect second-order consequences of selection-mediated changes in other (unmeasured) traits that are coupled with the focal trait via feedback regulation. Manipulative experiments to decipher circuits of feedback control and patterns of phenotypic integration can help identify causal relationships that underlie observed genotype–phenotype associations. Such experiments are critical for correct inferences about phenotypic targets of selection and mechanisms of adaptation.
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Affiliation(s)
- Jay F Storz
- School of Biological Sciences, University of Nebraska, Lincoln, NE, USA
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10
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Abstract
Hypoxia at high altitudes can constrain the ability of endotherms to maintain sufficient rates of pulmonary O2 transport to support exercise and thermogenesis. Hypoxia can also impede lung development during early post-natal life in some mammals, and could thus accentuate constraints on O2 transport at high altitude. We examined how these challenges are overcome in deer mice (Peromyscus maniculatus) native to high altitude. Lung structure was examined in highland and lowland populations of deer mice and lowland populations of white-footed mice (P. leucopus; a congener restricted to low altitude) that were bred in captivity. Among mice that were born and raised to adulthood in normoxia, highland deer mice had higher alveolar surface density and more densely packed alveoli. The increased alveolar surface density in highlanders became fully apparent at juvenile life stages at post-natal day 30 (P30), after the early developmental period of intense alveolus formation before P21. Alveolar surface density was maintained in highlanders that were conceived, born, and raised in hypoxia (~ 12 kPa O2), suggesting that lung development was not impaired by post-natal hypoxia as it is in many other lowland mammals. However, developmental hypoxia increased lung volume and thus augmented total alveolar surface area from P14. Overall, our findings suggest that evolutionary adaptation and developmental plasticity lead to changes in lung morphology that should improve pulmonary O2 uptake in deer mice native to high altitude.
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Affiliation(s)
- Claire M West
- Department of Biology, McMaster University, Hamilton, ON, L8S 4K1, Canada
| | - Catherine M Ivy
- Department of Biology, McMaster University, Hamilton, ON, L8S 4K1, Canada
| | - Renata Husnudinov
- Department of Biology, McMaster University, Hamilton, ON, L8S 4K1, Canada
| | - Graham R Scott
- Department of Biology, McMaster University, Hamilton, ON, L8S 4K1, Canada.
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11
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Storz JF, Scott GR. Phenotypic plasticity, genetic assimilation, and genetic compensation in hypoxia adaptation of high-altitude vertebrates. Comp Biochem Physiol A Mol Integr Physiol 2021; 253:110865. [PMID: 33301891 PMCID: PMC7867641 DOI: 10.1016/j.cbpa.2020.110865] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 12/03/2020] [Accepted: 12/04/2020] [Indexed: 12/20/2022]
Abstract
Important questions about mechanisms of physiological adaptation concern the role of phenotypic plasticity and the extent to which acclimatization responses align with genetic responses to selection. Such questions can be addressed in experimental studies of high-altitude vertebrates by investigating how mechanisms of acclimatization to hypoxia in lowland natives may influence genetic adaptation to hypoxia in highland natives. Evidence from high-altitude mammals suggest that evolved changes in some physiological traits involved canalization of the ancestral acclimatization response to hypoxia (genetic assimilation), a mechanism that results in an evolved reduction in plasticity. In addition to cases where adaptive plasticity may have facilitated genetic adaptation, evidence also suggests that some physiological changes in high-altitude natives are the result of selection to mitigate maladaptive plastic responses to hypoxia (genetic compensation). Examples of genetic compensation involve the attenuation of hypoxic pulmonary hypertension in Tibetan humans and other mammals native to high altitude. Here we discuss examples of adaptive physiological phenotypes in high-altitude natives that may have evolved by means of genetic assimilation or genetic compensation.
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Affiliation(s)
- Jay F Storz
- School of Biological Sciences, University of Nebraska, Lincoln, NE, USA.
| | - Graham R Scott
- Department of Biology, McMaster University, Hamilton, ON, Canada
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12
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West CM, Ivy CM, Husnudinov R, Scott GR. Evolution and developmental plasticity of lung structure in high-altitude deer mice. J Comp Physiol B 2021; 191:385-396. [PMID: 33533958 DOI: 10.1007/s00360-021-01343-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2020] [Revised: 01/08/2021] [Accepted: 01/18/2021] [Indexed: 01/12/2023]
Abstract
Hypoxia at high altitudes can constrain the ability of endotherms to maintain sufficient rates of pulmonary O2 transport to support exercise and thermogenesis. Hypoxia can also impede lung development during early post-natal life in some mammals, and could thus accentuate constraints on O2 transport at high altitude. We examined how these challenges are overcome in deer mice (Peromyscus maniculatus) native to high altitude. Lung structure was examined in highland and lowland populations of deer mice and lowland populations of white-footed mice (P. leucopus; a congener restricted to low altitude) that were bred in captivity. Among mice that were born and raised to adulthood in normoxia, highland deer mice had higher alveolar surface density and more densely packed alveoli. The increased alveolar surface density in highlanders became fully apparent at juvenile life stages at post-natal day 30 (P30), after the early developmental period of intense alveolus formation before P21. Alveolar surface density was maintained in highlanders that were conceived, born, and raised in hypoxia (~ 12 kPa O2), suggesting that lung development was not impaired by post-natal hypoxia as it is in many other lowland mammals. However, developmental hypoxia increased lung volume and thus augmented total alveolar surface area from P14. Overall, our findings suggest that evolutionary adaptation and developmental plasticity lead to changes in lung morphology that should improve pulmonary O2 uptake in deer mice native to high altitude.
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Affiliation(s)
- Claire M West
- Department of Biology, McMaster University, Hamilton, ON, L8S 4K1, Canada
| | - Catherine M Ivy
- Department of Biology, McMaster University, Hamilton, ON, L8S 4K1, Canada
| | - Renata Husnudinov
- Department of Biology, McMaster University, Hamilton, ON, L8S 4K1, Canada
| | - Graham R Scott
- Department of Biology, McMaster University, Hamilton, ON, L8S 4K1, Canada.
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13
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Abstract
Population genomic studies of humans and other animals at high altitude have generated many hypotheses about the genes and pathways that may have contributed to hypoxia adaptation. Future advances require experimental tests of such hypotheses to identify causal mechanisms. Studies to date illustrate the challenge of moving from lists of candidate genes to the identification of phenotypic targets of selection, as it can be difficult to determine whether observed genotype-phenotype associations reflect causal effects or secondary consequences of changes in other traits that are linked via homeostatic regulation. Recent work on high-altitude models such as deer mice has revealed both plastic and evolved changes in respiratory, cardiovascular, and metabolic traits that contribute to aerobic performance capacity in hypoxia, and analyses of tissue-specific transcriptomes have identified changes in regulatory networks that mediate adaptive changes in physiological phenotype. Here we synthesize recent results and discuss lessons learned from studies of high-altitude adaptation that lie at the intersection of genomics and physiology.
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Affiliation(s)
- Jay F Storz
- School of Biological Sciences, University of Nebraska, Lincoln, Nebraska 68588, USA;
| | - Zachary A Cheviron
- Division of Biological Sciences, University of Montana, Missoula, Montana 59812, USA;
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14
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Mairbäurl H, Gassmann M, Muckenthaler MU. Geographical ancestry affects normal hemoglobin values in high-altitude residents. J Appl Physiol (1985) 2020; 129:1451-1459. [PMID: 33002380 DOI: 10.1152/japplphysiol.00025.2020] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Increasing the hemoglobin (Hb) concentration is a major mechanism adjusting arterial oxygen content to decreased oxygen partial pressure of inspired air at high altitude. Approximately 5% of the world's population living at altitudes higher than 1,500 m shows this adaptive mechanism. Notably, there is a wide variation in the extent of increase in Hb concentration among different populations. This short review summarizes available information on Hb concentrations of high-altitude residents living at comparable altitudes (3,500-4,500 m) in different regions of the world. An increased Hb concentration is found in all high-altitude populations. The highest mean Hb concentration was found in adult male Andean residents and in Han Chinese living at high altitude, whereas it was lowest in Ethiopians, Tibetans, and Sherpas. A lower plasma volume in Andean high-altitude natives may offer a partial explanation. Indeed, male Andean high-altitude natives have a lower plasma volume than Tibetans and Ethiopians. Moreover, Hb values were lower in adult, nonpregnant females than in males; differences between populations of different ancestry were less pronounced. Various genetic polymorphisms were detected in high-altitude residents thought to favor life in a hypoxic environment, some of which correlate with the relatively low Hb concentration in the Tibetans and Ethiopians, whereas differences in angiotensin-converting enzyme allele distribution may be related to elevated Hb in the Andeans. Taken together, these results indicate different sensitivity of oxygen dependent control of erythropoiesis or plasma volume among populations of different geographical ancestry, offering explanations for differences in the Hb concentration at high altitude.
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Affiliation(s)
- Heimo Mairbäurl
- Departmment of Translational Pneumology, University Hospital Heidelberg, Heidelberg, Germany.,Translational Lung Research Center Heidelberg, Member of the German Center for Lung Research, Heidelberg, Germany
| | - Max Gassmann
- Vetsuisse Faculty, Institute of Veterinary Physiology, University of Zurich, Zurich, Switzerland.,Zurich Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland.,Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Martina U Muckenthaler
- Translational Lung Research Center Heidelberg, Member of the German Center for Lung Research, Heidelberg, Germany.,Departmment of Pediatric Hematology, Oncology and Immunology, University Hospital Heidelberg, Heidelberg, Germany.,Molecular Medicine Partnership Unit, University of Heidelberg, Heidelberg, Germany.,German Centre for Cardiovascular Research, Partner Site Heidelberg/Mannheim, Germany
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15
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Li J, Li Y, Atakan MM, Kuang J, Hu Y, Bishop DJ, Yan X. The Molecular Adaptive Responses of Skeletal Muscle to High-Intensity Exercise/Training and Hypoxia. Antioxidants (Basel) 2020; 9:E656. [PMID: 32722013 PMCID: PMC7464156 DOI: 10.3390/antiox9080656] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Revised: 07/19/2020] [Accepted: 07/21/2020] [Indexed: 12/31/2022] Open
Abstract
High-intensity exercise/training, especially interval exercise/training, has gained popularity in recent years. Hypoxic training was introduced to elite athletes half a century ago and has recently been adopted by the general public. In the current review, we have summarised the molecular adaptive responses of skeletal muscle to high-intensity exercise/training, focusing on mitochondrial biogenesis, angiogenesis, and muscle fibre composition. The literature suggests that (peroxisome proliferator-activated receptor gamma coactivator 1-alpha) PGC-1α, vascular endothelial growth factor (VEGF), and hypoxia-inducible factor 1-alpha (HIF1-α) might be the main mediators of skeletal muscle adaptations to high-intensity exercises in hypoxia. Exercise is known to be anti-inflammatory, while the effects of hypoxia on inflammatory signalling are more complex. The anti-inflammatory effects of a single session of exercise might result from the release of anti-inflammatory myokines and other cytokines, as well as the downregulation of Toll-like receptor signalling, while training-induced anti-inflammatory effects may be due to reductions in abdominal and visceral fat (which are main sources of pro-inflammatory cytokines). Hypoxia can lead to inflammation, and inflammation can result in tissue hypoxia. However, the hypoxic factor HIF1-α is essential for preventing excessive inflammation. Disease-induced hypoxia is related to an upregulation of inflammatory signalling, but the effects of exercise-induced hypoxia on inflammation are less conclusive. The effects of high-intensity exercise under hypoxia on skeletal muscle molecular adaptations and inflammatory signalling have not been fully explored and are worth investigating in future studies. Understanding these effects will lead to a more comprehensive scientific basis for maximising the benefits of high-intensity exercise.
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Affiliation(s)
- Jia Li
- College of Physical Education, Southwest University, Chongqing 400715, China;
- Institute for Health and Sport (iHeS), Victoria University, P.O. Box 14428, Melbourne 8001, Australia; (M.M.A.); (J.K.); (D.J.B.)
| | - Yanchun Li
- China Institute of Sport and Health Science, Beijing Sport University, Beijing 100192, China; (Y.L.); (Y.H.)
| | - Muhammed M. Atakan
- Institute for Health and Sport (iHeS), Victoria University, P.O. Box 14428, Melbourne 8001, Australia; (M.M.A.); (J.K.); (D.J.B.)
- Division of Nutrition and Metabolism in Exercise, Faculty of Sport Sciences, Hacettepe University, 06800 Ankara, Turkey
| | - Jujiao Kuang
- Institute for Health and Sport (iHeS), Victoria University, P.O. Box 14428, Melbourne 8001, Australia; (M.M.A.); (J.K.); (D.J.B.)
| | - Yang Hu
- China Institute of Sport and Health Science, Beijing Sport University, Beijing 100192, China; (Y.L.); (Y.H.)
| | - David J. Bishop
- Institute for Health and Sport (iHeS), Victoria University, P.O. Box 14428, Melbourne 8001, Australia; (M.M.A.); (J.K.); (D.J.B.)
| | - Xu Yan
- Institute for Health and Sport (iHeS), Victoria University, P.O. Box 14428, Melbourne 8001, Australia; (M.M.A.); (J.K.); (D.J.B.)
- Sarcopenia Research Program, Australia Institute for Musculoskeletal Sciences (AIMSS), Melbourne 3021, Australia
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16
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Tate KB, Wearing OH, Ivy CM, Cheviron ZA, Storz JF, McClelland GB, Scott GR. Coordinated changes across the O 2 transport pathway underlie adaptive increases in thermogenic capacity in high-altitude deer mice. Proc Biol Sci 2020; 287:20192750. [PMID: 32429808 PMCID: PMC7287372 DOI: 10.1098/rspb.2019.2750] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Accepted: 04/24/2020] [Indexed: 01/19/2023] Open
Abstract
Animals native to the hypoxic and cold environment at high altitude provide an excellent opportunity to elucidate the integrative mechanisms underlying the adaptive evolution and plasticity of complex traits. The capacity for aerobic thermogenesis can be a critical determinant of survival for small mammals at high altitude, but the physiological mechanisms underlying the evolution of this performance trait remain unresolved. We examined this issue by comparing high-altitude deer mice (Peromyscus maniculatus) with low-altitude deer mice and white-footed mice (P. leucopus). Mice were bred in captivity and adults were acclimated to each of four treatments: warm (25°C) normoxia, warm hypoxia (12 kPa O2), cold (5°C) normoxia or cold hypoxia. Acclimation to hypoxia and/or cold increased thermogenic capacity in deer mice, but hypoxia acclimation led to much greater increases in thermogenic capacity in highlanders than in lowlanders. The high thermogenic capacity of highlanders was associated with increases in pulmonary O2 extraction, arterial O2 saturation, cardiac output and arterial-venous O2 difference. Mechanisms underlying the evolution of enhanced thermogenic capacity in highlanders were partially distinct from those underlying the ancestral acclimation responses of lowlanders. Environmental adaptation has thus enhanced phenotypic plasticity and expanded the physiological toolkit for coping with the challenges at high altitude.
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Affiliation(s)
- Kevin B. Tate
- Department of Biology, McMaster University, Hamilton, ON L8S 4K1, Canada
- Department of Biology, Texas Lutheran University, Seguin, TX 78155, USA
| | - Oliver H. Wearing
- Department of Biology, McMaster University, Hamilton, ON L8S 4K1, Canada
| | - Catherine M. Ivy
- Department of Biology, McMaster University, Hamilton, ON L8S 4K1, Canada
| | - Zachary A. Cheviron
- Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA
| | - Jay F. Storz
- School of Biological Sciences, University of Nebraska, Lincoln, NE 68588, USA
| | | | - Graham R. Scott
- Department of Biology, McMaster University, Hamilton, ON L8S 4K1, Canada
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17
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Ulrich S, Furian M, Estebesova B, Toktogulova N, Beishekeeva G, Ulrich S, Burney PGJ, Sooronbaev TM, Bloch KE. Spirometry in Central Asian Lowlanders and Highlanders, a Population Based Study. Front Med (Lausanne) 2020; 6:308. [PMID: 31998729 PMCID: PMC6966711 DOI: 10.3389/fmed.2019.00308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2019] [Accepted: 12/05/2019] [Indexed: 11/13/2022] Open
Abstract
Introduction: The purpose of the study was to establish spirometric reference values for a Central Asian population of highlanders and lowlanders. Methods: Spirometries from a population-based cross-sectional study performed in 2013 in rural areas of Kyrgyzstan were analyzed. Using multivariable linear regression, Global Lung Function Initiative (GLI) equations were fitted separately for men and women, and altitude of residence (700–800 m, 1,900–2,800 m) to data from healthy, never-smoking Kyrgyz adults. The general GLI equation was applied:
Predicted value=ea0+a1× ln(Height)+a2× ln(Age)+b1× ln(Age100)+b2× ln(Age100)2+b3× ln(Age100)3 +b4× ln(Age100)4+b5× ln(Age100)5 Results: Of 2,784 screened Kyrgyz, 448 healthy, non-smoking highlanders (379 females) and 505 lowlanders (368 females), aged 18–91 years, were included. Predicted FVC in Kyrgyz fit best with GLI “North-East Asians,” predicted FEV1 fit best with GLI “Other/Mixed.” Predicted FEV1/FVC was lower than that of all GLI categories. Age- and sex-adjusted mean FVC and FEV1 were higher in highlanders (+0.138l, +0.132l) than in lowlanders (P < 0.001, all comparisons), but FEV1/FVC was similar. Conclusion: We established prediction equations for an adult Central Asian population indicating that FVC is similar to GLI “North-East Asian” and FEV1/FVC is lower than in all other GLI population categories, consistent with a relatively smaller airway caliber. Central Asian highlanders have significantly greater dynamic lung volumes compared to lowlanders, which may be due to environmental and various other effects.
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Affiliation(s)
- Stefanie Ulrich
- Department of Respiratory Medicine, University Hospital Zurich, Zurich, Switzerland
| | - Michael Furian
- Department of Respiratory Medicine, University Hospital Zurich, Zurich, Switzerland
| | - Bermet Estebesova
- Department of Respiratory Medicine, National Center for Cardiology and Internal Medicine, Bishkek, Kyrgyzstan
| | - Nurgul Toktogulova
- Therapy 1 Department, Medical Faculty, Kyrgyz-Russian Slavic University, Bishkek, Kyrgyzstan
| | - Gulnara Beishekeeva
- Therapy 1 Department, Medical Faculty, Kyrgyz-Russian Slavic University, Bishkek, Kyrgyzstan
| | - Silvia Ulrich
- Department of Respiratory Medicine, University Hospital Zurich, Zurich, Switzerland
| | - Peter G J Burney
- Population Health and Occupational Disease, National Heart and Lung Institute & MRC-PHE Centre for Environment and Health, Imperial College London, London, United Kingdom
| | - Talant M Sooronbaev
- Department of Respiratory Medicine, National Center for Cardiology and Internal Medicine, Bishkek, Kyrgyzstan
| | - Konrad E Bloch
- Department of Respiratory Medicine, University Hospital Zurich, Zurich, Switzerland
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18
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González-Andrade F. High Altitude as a Cause of Congenital Heart Defects: A Medical Hypothesis Rediscovered in Ecuador. High Alt Med Biol 2020; 21:126-134. [PMID: 31976751 DOI: 10.1089/ham.2019.0110] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Background: There are ∼83 million people living at high altitude (>2500 m) worldwide who endure chronic hypoxia conditions. This article aims to analyze the relationship between high altitude, identified in several cities in Ecuador, and the prevalence of congenital heart disease (CHD). Methods: Set in Ecuador, this epidemiological observational cross-sectional study analyzes data over a range of 18 years (from 2000 to 2017), including 34,904 reported cases of CHD, with a mean of 1939 cases per year. Results: The mean prevalence rate of CHD found is 70.6 per 10,000 live newborns. A K-means analysis resulted in three clusters. Cluster 1 shows the lowest altitude and prevalence of CHD, with an average of 2619 m and 63.02 cases per 10,000 live newborns. Cluster 2 presents the second highest altitude and prevalence of CHD, with an average of 2909 m and 72.04 cases per 10,000 live newborns. Cluster 3 shows the highest values of altitude and prevalence of CHD, with an average of 3176 m and 86.62 cases per 10,000 live newborns. Pearson's coefficient is 0.979, so the correlation between the variables is positive. An altitude ranging from 2500 to 2750 m relates to a prevalence of CHD of ≤71 cases per 10,000 live newborns. An altitude ranging from 2751 to 3000 m relates to a prevalence of CHD of >71 and <89 cases per 10,000 live newborns. An altitude ranging between 3001 and 3264 m relates to a prevalence of CHD of ≥89 cases per 10,000 live newborns. Conclusions: The findings show that high altitude (>2500 m), ethnicity (Native American), rural locations, and limited access to health care are factors that influence and increase the prevalence rate of CHD. A correlation coefficient of 0.914 shows the direct relationship between high altitude and prevalence rates of CHD. For each year elapsed, the prevalence of CHD increased by 3.33 cases per 10,000 live newborns.
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Affiliation(s)
- Fabricio González-Andrade
- Unidad de Medicina Traslacional, Facultad de Ciencias Médicas, Universidad Central del Ecuador, Quito, Ecuador.,Colegio Ciencias de la Salud, Universidad San Francisco de Quito USFQ, Quito, Ecuador
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19
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Burykh EA. The Problem of Assessing Individual Sensitivity and Tolerance to Hypoxia in Animals and Humans. J EVOL BIOCHEM PHYS+ 2019. [DOI: 10.1134/s0022093019050016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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20
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Storz JF, Scott GR. Life Ascending: Mechanism and Process in Physiological Adaptation to High-Altitude Hypoxia. ANNUAL REVIEW OF ECOLOGY EVOLUTION AND SYSTEMATICS 2019; 50:503-526. [PMID: 33033467 DOI: 10.1146/annurev-ecolsys-110218-025014] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
To cope with the reduced availability of O2 at high altitude, air-breathing vertebrates have evolved myriad adjustments in the cardiorespiratory system to match tissue O2 delivery with metabolic O2 demand. We explain how changes at interacting steps of the O2 transport pathway contribute to plastic and evolved changes in whole-animal aerobic performance under hypoxia. In vertebrates native to high altitude, enhancements of aerobic performance under hypoxia are attributable to a combination of environmentally induced and evolved changes in multiple steps of the pathway. Additionally, evidence suggests that many high-altitude natives have evolved mechanisms for attenuating maladaptive acclimatization responses to hypoxia, resulting in counter-gradient patterns of altitudinal variation for key physiological phenotypes. For traits that exhibit counteracting environmental and genetic effects, evolved changes in phenotype may be cryptic under field conditions and can only be revealed by rearing representatives of high-and low-altitude populations under standardized environmental conditions to control for plasticity.
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Affiliation(s)
- Jay F Storz
- School of Biological Sciences, University of Nebraska, Lincoln, Nebraska 68588, USA
| | - Graham R Scott
- Department of Biology, McMaster University, Hamilton, Ontario L8S 4K1, Canada
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21
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Grocott MPW, Levett DZH, Ward SA. Exercise physiology: exercise performance at altitude. CURRENT OPINION IN PHYSIOLOGY 2019. [DOI: 10.1016/j.cophys.2019.06.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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22
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Storz JF, Cheviron ZA, McClelland GB, Scott GR. Evolution of physiological performance capacities and environmental adaptation: insights from high-elevation deer mice ( Peromyscus maniculatus). J Mammal 2019; 100:910-922. [PMID: 31138949 DOI: 10.1093/jmammal/gyy173] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Accepted: 12/14/2018] [Indexed: 12/14/2022] Open
Abstract
Analysis of variation in whole-animal performance can shed light on causal connections between specific traits, integrated physiological capacities, and Darwinian fitness. Here, we review and synthesize information on naturally occurring variation in physiological performance capacities and how it relates to environmental adaptation in deer mice (Peromyscus maniculatus). We discuss how evolved changes in aerobic exercise capacity and thermogenic capacity have contributed to adaptation to high elevations. Comparative work on deer mice at high and low elevations has revealed evolved differences in aerobic performance capacities in hypoxia. Highland deer mice have consistently higher aerobic performance capacities under hypoxia relative to lowland natives, consistent with the idea that it is beneficial to have a higher maximal metabolic rate (as measured by the maximal rate of O2 consumption, VO2max) in an environment characterized by lower air temperatures and lower O2 availability. Observed differences in aerobic performance capacities between highland and lowland deer mice stem from changes in numerous subordinate traits that alter the flux capacity of the O2-transport system, the oxidative capacity of tissue mitochondria, and the relationship between O2 consumption and ATP synthesis. Many such changes in physiological phenotype are associated with hypoxia-induced changes in gene expression. Research on natural variation in whole-animal performance forms a nexus between physiological ecology and evolutionary biology that requires insight into the natural history of the study species.
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Affiliation(s)
- Jay F Storz
- School of Biological Sciences, University of Nebraska, Lincoln, NE, USA
| | - Zachary A Cheviron
- Division of Biological Sciences, University of Montana, Missoula, MT, USA
| | | | - Graham R Scott
- Department of Biology, McMaster University, Hamilton, Ontario, Canada
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23
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Ivy CM, Lague SL, York JM, Chua BA, Alza L, Cheek R, Dawson NJ, Frappell PB, McCracken KG, Milsom WK, Scott GR. Control of breathing and respiratory gas exchange in high-altitude ducks native to the Andes. ACTA ACUST UNITED AC 2019; 222:jeb.198622. [PMID: 30846536 DOI: 10.1242/jeb.198622] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Accepted: 03/03/2019] [Indexed: 11/20/2022]
Abstract
We examined the control of breathing and respiratory gas exchange in six species of high-altitude duck that independently colonized the high Andes. We compared ducks from high-altitude populations in Peru (Lake Titicaca at ∼3800 m above sea level; Chancay River at ∼3000-4100 m) with closely related populations or species from low altitude. Hypoxic ventilatory responses were measured shortly after capture at the native altitude. In general, ducks responded to acute hypoxia with robust increases in total ventilation and pulmonary O2 extraction. O2 consumption rates were maintained or increased slightly in acute hypoxia, despite ∼1-2°C reductions in body temperature in most species. Two high-altitude taxa - yellow-billed pintail and torrent duck - exhibited higher total ventilation than their low-altitude counterparts, and yellow-billed pintail exhibited greater increases in pulmonary O2 extraction in severe hypoxia. In contrast, three other high-altitude taxa - Andean ruddy duck, Andean cinnamon teal and speckled teal - had similar or slightly reduced total ventilation and pulmonary O2 extraction compared with low-altitude relatives. Arterial O2 saturation (S aO2 ) was elevated in yellow-billed pintails at moderate levels of hypoxia, but there were no differences in S aO2 in other high-altitude taxa compared with their close relatives. This finding suggests that improvements in S aO2 in hypoxia can require increases in both breathing and haemoglobin-O2 affinity, because the yellow-billed pintail was the only high-altitude duck with concurrent increases in both traits compared with its low-altitude relative. Overall, our results suggest that distinct physiological strategies for coping with hypoxia can exist across different high-altitude lineages, even among those inhabiting very similar high-altitude habitats.
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Affiliation(s)
- Catherine M Ivy
- Department of Biology, McMaster University, Hamilton, ON, Canada, L8S 4K1
| | - Sabine L Lague
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada, V6T 1Z4
| | - Julia M York
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada, V6T 1Z4.,Department of Integrative Biology, University of Texas at Austin, TX 78712, USA
| | - Beverly A Chua
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada, V6T 1Z4
| | - Luis Alza
- Department of Biology and Department of Marine Biology and Ecology, Rosenstiel School of Marine and Atmospheric Sciences, University of Miami, Coral Gables, FL 33146, USA.,Division of Ornithology, Centro de Ornitologia y Biodiversidad, Lima 33, Peru.,Department of Biology and Wildlife, Institute of Arctic Biology and University of Alaska Museum, University of Alaska Fairbanks, AK 99755, USA
| | - Rebecca Cheek
- Department of Biology and Wildlife, Institute of Arctic Biology and University of Alaska Museum, University of Alaska Fairbanks, AK 99755, USA
| | - Neal J Dawson
- Department of Biology, McMaster University, Hamilton, ON, Canada, L8S 4K1
| | - Peter B Frappell
- Zoology Department, Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Tasmania 7001, Australia
| | - Kevin G McCracken
- Department of Biology and Department of Marine Biology and Ecology, Rosenstiel School of Marine and Atmospheric Sciences, University of Miami, Coral Gables, FL 33146, USA.,Division of Ornithology, Centro de Ornitologia y Biodiversidad, Lima 33, Peru.,Department of Biology and Wildlife, Institute of Arctic Biology and University of Alaska Museum, University of Alaska Fairbanks, AK 99755, USA.,Human Genetics and Genomics, University of Miller School of Medicine, Miami, FL 33136, USA
| | - William K Milsom
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada, V6T 1Z4
| | - Graham R Scott
- Department of Biology, McMaster University, Hamilton, ON, Canada, L8S 4K1
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24
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Scott GR, Guo KH, Dawson NJ. The Mitochondrial Basis for Adaptive Variation in Aerobic Performance in High-Altitude Deer Mice. Integr Comp Biol 2019; 58:506-518. [PMID: 29873740 DOI: 10.1093/icb/icy056] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Mitochondria play a central role in aerobic performance. Studies aimed at elucidating how evolved variation in mitochondrial physiology contributes to adaptive variation in aerobic performance can therefore provide a unique and powerful lens to understanding the evolution of complex physiological traits. Here, we review our ongoing work on the importance of changes in mitochondrial quantity and quality to adaptive variation in aerobic performance in high-altitude deer mice. Whole-organism aerobic capacity in hypoxia (VO2max) increases in response to hypoxia acclimation in this species, but high-altitude populations have evolved consistently greater VO2max than populations from low altitude. The evolved increase in VO2max in highlanders is associated with an evolved increase in the respiratory capacity of the gastrocnemius muscle. This appears to result from highlanders having more mitochondria in this tissue, attributed to a higher proportional abundance of oxidative fiber-types and a greater mitochondrial volume density within oxidative fibers. The latter is primarily caused by an over-abundance of subsarcolemmal mitochondria in high-altitude mice, which is likely advantageous for mitochondrial O2 supply because more mitochondria are situated adjacent to the cell membrane and close to capillaries. Evolved changes in gastrocnemius phenotype appear to be underpinned by population differences in the expression of genes involved in energy metabolism, muscle development, and vascular development. Hypoxia acclimation has relatively little effect on respiratory capacity of the gastrocnemius, but it increases respiratory capacity of the diaphragm. However, the mechanisms responsible for this increase differ between populations: lowlanders appear to adjust mitochondrial quantity and quality (i.e., increases in citrate synthase [CS] activity, and mitochondrial respiration relative to CS activity) and they exhibit higher rates of mitochondrial release of reactive oxygen species, whereas highlanders only increase mitochondrial quantity in response to hypoxia acclimation. In contrast to the variation in skeletal muscles, the respiratory capacity of cardiac muscle does not appear to be affected by hypoxia acclimation and varies little between populations. Therefore, evolved changes in mitochondrial quantity and quality make important tissue-specific contributions to adaptive variation in aerobic performance in high-altitude deer mice.
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Affiliation(s)
- Graham R Scott
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4K1
| | - Kevin H Guo
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4K1
| | - Neal J Dawson
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4K1
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25
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McClelland GB, Scott GR. Evolved Mechanisms of Aerobic Performance and Hypoxia Resistance in High-Altitude Natives. Annu Rev Physiol 2018; 81:561-583. [PMID: 30256727 DOI: 10.1146/annurev-physiol-021317-121527] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Comparative physiology studies of high-altitude species provide an exceptional opportunity to understand naturally evolved mechanisms of hypoxia resistance. Aerobic capacity (VO2max) is a critical performance trait under positive selection in some high-altitude taxa, and several high-altitude natives have evolved to resist the depressive effects of hypoxia on VO2max. This is associated with enhanced flux capacity through the O2 transport cascade and attenuation of the maladaptive responses to chronic hypoxia that can impair O2 transport. Some highlanders exhibit elevated rates of carbohydrate oxidation during exercise, taking advantage of its high ATP yield per mole of O2. Certain highland native animals have also evolved more oxidative muscles and can sustain high rates of lipid oxidation to support thermogenesis. The underlying mechanisms include regulatory adjustments of metabolic pathways and to gene expression networks. Therefore, the evolution of hypoxia resistance in high-altitude natives involves integrated functional changes in the pathways for O2 and substrate delivery and utilization by mitochondria.
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Affiliation(s)
- Grant B McClelland
- Department of Biology, McMaster University, Hamilton, Ontario L8S 4K1, Canada;
| | - Graham R Scott
- Department of Biology, McMaster University, Hamilton, Ontario L8S 4K1, Canada;
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Ivy CM, Scott GR. Evolved changes in breathing and CO 2 sensitivity in deer mice native to high altitudes. Am J Physiol Regul Integr Comp Physiol 2018; 315:R1027-R1037. [PMID: 30183337 DOI: 10.1152/ajpregu.00220.2018] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
We examined the control of breathing by O2 and CO2 in deer mice native to high altitude to help uncover the physiological specializations used to cope with hypoxia in high-altitude environments. Highland deer mice ( Peromyscus maniculatus) and lowland white-footed mice ( P. leucopus) were bred in captivity at sea level. The first and second generation progeny of each population was raised to adulthood and then acclimated to normoxia or hypobaric hypoxia (12 kPa O2, simulating hypoxia at ~4,300 m) for 6-8 wk. Ventilatory responses to poikilocapnic hypoxia (stepwise reductions in inspired O2) and hypercapnia (stepwise increases in inspired CO2) were then compared between groups. Both generations of lowlanders appeared to exhibit ventilatory acclimatization to hypoxia (VAH), in which hypoxia acclimation enhanced the hypoxic ventilatory response and/or made the breathing pattern more effective (higher tidal volumes and lower breathing frequencies at a given total ventilation). In contrast, hypoxia acclimation had no effect on breathing in either generation of highlanders, and breathing was generally similar to hypoxia-acclimated lowlanders. Therefore, attenuation of VAH may be an evolved feature of highlanders that persists for multiple generations in captivity. Hypoxia acclimation increased CO2 sensitivity of breathing, but in this case, the effect of hypoxia acclimation was similar in highlanders and lowlanders. Our results suggest that highland deer mice have evolved high rates of alveolar ventilation that are unaltered by exposure to chronic hypoxia, but they have preserved ventilatory sensitivity to CO2.
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Affiliation(s)
- Catherine M Ivy
- Department of Biology, McMaster University , Hamilton, ON , Canada
| | - Graham R Scott
- Department of Biology, McMaster University , Hamilton, ON , Canada
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Burtscher M, Gatterer H, Burtscher J, Mairbäurl H. Extreme Terrestrial Environments: Life in Thermal Stress and Hypoxia. A Narrative Review. Front Physiol 2018; 9:572. [PMID: 29867589 PMCID: PMC5964295 DOI: 10.3389/fphys.2018.00572] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Accepted: 04/30/2018] [Indexed: 12/22/2022] Open
Abstract
Living, working and exercising in extreme terrestrial environments are challenging tasks even for healthy humans of the modern new age. The issue is not just survival in remote environments but rather the achievement of optimal performance in everyday life, occupation, and sports. Various adaptive biological processes can take place to cope with the specific stressors of extreme terrestrial environments like cold, heat, and hypoxia (high altitude). This review provides an overview of the physiological and morphological aspects of adaptive responses in these environmental stressors at the level of organs, tissues, and cells. Furthermore, adjustments existing in native people living in such extreme conditions on the earth as well as acute adaptive responses in newcomers are discussed. These insights into general adaptability of humans are complemented by outcomes of specific acclimatization/acclimation studies adding important information how to cope appropriately with extreme environmental temperatures and hypoxia.
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Affiliation(s)
- Martin Burtscher
- Department of Sport Science, University of Innsbruck, Innsbruck, Austria.,Austrian Society for Alpine and Mountain Medicine, Innsbruck, Austria
| | - Hannes Gatterer
- Department of Sport Science, University of Innsbruck, Innsbruck, Austria.,Institute of Mountain Emergency Medicine, EURAC Research, Bolzano, Italy
| | - Johannes Burtscher
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Heimo Mairbäurl
- Medical Clinic VII, Sports Medicine, University Hospital Heidelberg, Heidelberg, Germany.,German Center for Lung Research (DZL/TLRC-H), Heidelberg, Germany
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Ivy CM, York JM, Lague SL, Chua BA, Alza L, McCracken KG, Milsom WK, Scott GR. Validation of a Pulse Oximetry System for High-Altitude Waterfowl by Examining the Hypoxia Responses of the Andean Goose (Chloephaga melanoptera). Physiol Biochem Zool 2018. [DOI: 10.1086/697053] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Tate KB, Ivy CM, Velotta JP, Storz JF, McClelland GB, Cheviron ZA, Scott GR. Circulatory mechanisms underlying adaptive increases in thermogenic capacity in high-altitude deer mice. ACTA ACUST UNITED AC 2017; 220:3616-3620. [PMID: 28839010 DOI: 10.1242/jeb.164491] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Accepted: 08/18/2017] [Indexed: 01/08/2023]
Abstract
We examined the circulatory mechanisms underlying adaptive increases in thermogenic capacity in deer mice (Peromyscus maniculatus) native to the cold hypoxic environment at high altitudes. Deer mice from high- and low-altitude populations were born and raised in captivity to adulthood, and then acclimated to normoxia or hypobaric hypoxia (simulating hypoxia at ∼4300 m). Thermogenic capacity [maximal O2 consumption (V̇O2,max), during cold exposure] was measured in hypoxia, along with arterial O2 saturation (SaO2 ) and heart rate (fH). Hypoxia acclimation increased V̇O2,max by a greater magnitude in highlanders than in lowlanders. Highlanders also had higher SaO2 and extracted more O2 from the blood per heartbeat (O2 pulse=V̇O2,max/fH). Hypoxia acclimation increased fH, O2 pulse and capillary density in the left ventricle of the heart. Our results suggest that adaptive increases in thermogenic capacity involve integrated functional changes across the O2 cascade that augment O2 circulation and extraction from the blood.
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Affiliation(s)
- Kevin B Tate
- Department of Biology, McMaster University, Hamilton, ON, L8S 4K1, Canada.,School of Biological Sciences, University of Nebraska, Lincoln, NE 68588, USA
| | - Catherine M Ivy
- Department of Biology, McMaster University, Hamilton, ON, L8S 4K1, Canada
| | - Jonathan P Velotta
- Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA
| | - Jay F Storz
- School of Biological Sciences, University of Nebraska, Lincoln, NE 68588, USA
| | - Grant B McClelland
- Department of Biology, McMaster University, Hamilton, ON, L8S 4K1, Canada
| | - Zachary A Cheviron
- Division of Biological Sciences, University of Montana, Missoula, MT 59812, USA
| | - Graham R Scott
- Department of Biology, McMaster University, Hamilton, ON, L8S 4K1, Canada
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Persson PB, Bondke Persson A. Altitude sickness and altitude adaptation. Acta Physiol (Oxf) 2017; 220:303-306. [PMID: 28498559 DOI: 10.1111/apha.12894] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- P. B. Persson
- Institute of Vegetative Physiology; Charité-Universitaetsmedizin Berlin; Berlin Germany
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