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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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Dai S, Feng Y, Lu C, Zhang H, Ma W, Xie W, Wu X, Luo P, Zhang L, Fei F, Fei Z, Li X. Impairment of Autophagic Flux After Hypobaric Hypoxia Potentiates Oxidative Stress and Cognitive Function Disturbances in Mice. Neurosci Bull 2024; 40:35-49. [PMID: 37608137 PMCID: PMC10774493 DOI: 10.1007/s12264-023-01099-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2022] [Accepted: 06/01/2023] [Indexed: 08/24/2023] Open
Abstract
Acute hypobaric hypoxic brain damage is a potentially fatal high-altitude sickness. Autophagy plays a critical role in ischemic brain injury, but its role in hypobaric hypoxia (HH) remains unknown. Here we used an HH chamber to demonstrate that acute HH exposure impairs autophagic activity in both the early and late stages of the mouse brain, and is partially responsible for HH-induced oxidative stress, neuronal loss, and brain damage. The autophagic agonist rapamycin only promotes the initiation of autophagy. By proteome analysis, a screen showed that protein dynamin2 (DNM2) potentially regulates autophagic flux. Overexpression of DNM2 significantly increased the formation of autolysosomes, thus maintaining autophagic flux in combination with rapamycin. Furthermore, the enhancement of autophagic activity attenuated oxidative stress and neurological deficits after HH exposure. These results contribute to evidence supporting the conclusion that DNM2-mediated autophagic flux represents a new therapeutic target in HH-induced brain damage.
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Affiliation(s)
- Shuhui Dai
- Department of Neurosurgery, Xijing Hospital, Fourth Military Medical University, Xi'an, 710000, China
- National Translational Science Center for Molecular Medicine and Department of Cell Biology, Fourth Military Medical University, Xi'an, 710000, China
| | - Yuan Feng
- Department of Neurosurgery, Xijing Hospital, Fourth Military Medical University, Xi'an, 710000, China
| | - Chuanhao Lu
- Department of Neurosurgery, Xijing Hospital, Fourth Military Medical University, Xi'an, 710000, China
| | - Hongchen Zhang
- Department of Neurosurgery, Xijing Hospital, Fourth Military Medical University, Xi'an, 710000, China
| | - Wenke Ma
- Department of Neurosurgery, Xijing Hospital, Fourth Military Medical University, Xi'an, 710000, China
- Department of Neurosurgery, The Central Hospital of Baoji, Baoji, 721000, China
| | - Wenyu Xie
- Department of Neurosurgery, Xijing Hospital, Fourth Military Medical University, Xi'an, 710000, China
| | - Xiuquan Wu
- Department of Neurosurgery, Xijing Hospital, Fourth Military Medical University, Xi'an, 710000, China
| | - Peng Luo
- Department of Neurosurgery, Xijing Hospital, Fourth Military Medical University, Xi'an, 710000, China
| | - Lei Zhang
- Department of Neurosurgery, Xijing Hospital, Fourth Military Medical University, Xi'an, 710000, China
| | - Fei Fei
- Department of Ophthalmology, Xijing Hospital, Fourth Military Medical University, Xi'an, 710000, China
| | - Zhou Fei
- Department of Neurosurgery, Xijing Hospital, Fourth Military Medical University, Xi'an, 710000, China.
| | - Xia Li
- Department of Neurosurgery, Xijing Hospital, Fourth Military Medical University, Xi'an, 710000, China.
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Lai Y, Loy F, Isola M, Noli R, Rinaldi A, Lobina C, Vargiu R, Cesare Marincola F, Isola R. Male and Female Mitochondria Respond Differently after Exercising in Acute Hypoxia. Biomedicines 2023; 11:3149. [PMID: 38137370 PMCID: PMC10740434 DOI: 10.3390/biomedicines11123149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 11/10/2023] [Accepted: 11/20/2023] [Indexed: 12/24/2023] Open
Abstract
The use of hypoxic devices among athletes who train in normobaric hypoxia has become increasingly popular; however, the acute effects on heart and brain metabolism are not yet fully understood. This study aimed to investigate the mitochondrial bioenergetics in trained male and female Wistar rats after acute hypoxia training. The experimental plan included exercising for 30 min on a treadmill in a Plexiglas cage connected to a hypoxic generator set at 12.5% O2 or in normoxia. After the exercise, the rats were sacrificed, and their mitochondria were isolated from their brains and hearts. The bioenergetics for each complex of the electron transport chain was tested using a Clark-type electrode. The results showed that following hypoxia training, females experienced impaired oxidative phosphorylation through complex II in heart subsarcolemmal mitochondria, while males had an altered ADP/O in heart interfibrillar mitochondria, without any change in oxidative capacity. No differences from controls were evident in the brain, but an increased electron transport system efficiency was observed with complex I and IV substrates in males. Therefore, the study's findings suggest that hypoxia training affects the heart mitochondria of females more than males. This raises a cautionary flag for female athletes who use hypoxic devices.
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Affiliation(s)
- Ylenia Lai
- Department of Biological Sciences, University of Cagliari, Cittadella Universitaria di Monserrato, 09042 Monserrato, Italy
| | - Francesco Loy
- Department of Biological Sciences, University of Cagliari, Cittadella Universitaria di Monserrato, 09042 Monserrato, Italy
| | - Michela Isola
- Department of Biological Sciences, University of Cagliari, Cittadella Universitaria di Monserrato, 09042 Monserrato, Italy
| | - Roberta Noli
- Department of Biological Sciences, University of Cagliari, Cittadella Universitaria di Monserrato, 09042 Monserrato, Italy
| | - Andrea Rinaldi
- Department of Biological Sciences, University of Cagliari, Cittadella Universitaria di Monserrato, 09042 Monserrato, Italy
| | - Carla Lobina
- Neuroscience Institute, Division of Cagliari, National Research Council of Italy, Cittadella Universitaria di Monserrato, 09042 Monserrato, Italy
| | - Romina Vargiu
- Department of Biological Sciences, University of Cagliari, Cittadella Universitaria di Monserrato, 09042 Monserrato, Italy
| | - Flaminia Cesare Marincola
- Department of Chemical and Geological Sciences, University of Cagliari, Cittadella Universitaria di Monserrato, 09042 Monserrato, Italy
| | - Raffaella Isola
- Department of Biological Sciences, University of Cagliari, Cittadella Universitaria di Monserrato, 09042 Monserrato, Italy
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Song J, Duivenvoorde LPM, Grefte S, Kuda O, Martínez-Ramírez F, van der Stelt I, Mastorakou D, van Schothorst EM, Keijer J. Normobaric hypoxia shows enhanced FOXO1 signaling in obese mouse gastrocnemius muscle linked to metabolism and muscle structure and neuromuscular innervation. Pflugers Arch 2023; 475:1265-1281. [PMID: 37656229 PMCID: PMC10567817 DOI: 10.1007/s00424-023-02854-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 08/17/2023] [Accepted: 08/21/2023] [Indexed: 09/02/2023]
Abstract
Skeletal muscle relies on mitochondria for sustainable ATP production, which may be impacted by reduced oxygen availability (hypoxia). Compared with long-term hypoxia, the mechanistic in vivo response to acute hypoxia remains elusive. Therefore, we aimed to provide an integrated description of the Musculus gastrocnemius response to acute hypoxia. Fasted male C57BL/6JOlaHsd mice, fed a 40en% fat diet for six weeks, were exposed to 12% O2 normobaric hypoxia or normoxia (20.9% O2) for six hours (n = 12 per group). Whole-body energy metabolism and the transcriptome response of the M. gastrocnemius were analyzed and confirmed by acylcarnitine determination and Q-PCR. At the whole-body level, six hours of hypoxia reduced energy expenditure, increased blood glucose and tended to decreased the respiratory exchange ratio (RER). Whole-genome transcriptome analysis revealed upregulation of forkhead box-O (FOXO) signalling, including an increased expression of tribbles pseudokinase 3 (Trib3). Trib3 positively correlated with blood glucose levels. Upregulated carnitine palmitoyltransferase 1A negatively correlated with the RER, but the significantly increased in tissue C14-1, C16-0 and C18-1 acylcarnitines supported that β-oxidation was not regulated. The hypoxia-induced FOXO activation could also be connected to altered gene expression related to fiber-type switching, extracellular matrix remodeling, muscle differentiation and neuromuscular junction denervation. Our results suggest that a six-hour exposure of obese mice to 12% O2 normobaric hypoxia impacts M. gastrocnemius via FOXO1, initiating alterations that may contribute to muscle remodeling of which denervation is novel and warrants further investigation. The findings support an early role of hypoxia in tissue alterations in hypoxia-associated conditions such as aging and obesity.
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Affiliation(s)
- Jingyi Song
- Human and Animal Physiology, Wageningen University, Wageningen, The Netherlands
| | | | - Sander Grefte
- Human and Animal Physiology, Wageningen University, Wageningen, The Netherlands
| | - Ondrej Kuda
- Laboratory of Metabolism of Bioactive Lipids, Institute of Physiology, Czech Academy of Sciences, 14220, Prague 4, Czech Republic
| | - Felipe Martínez-Ramírez
- Laboratory of Metabolism of Bioactive Lipids, Institute of Physiology, Czech Academy of Sciences, 14220, Prague 4, Czech Republic
| | - Inge van der Stelt
- Human and Animal Physiology, Wageningen University, Wageningen, The Netherlands
| | - Dimitra Mastorakou
- Laboratory of Metabolism of Bioactive Lipids, Institute of Physiology, Czech Academy of Sciences, 14220, Prague 4, Czech Republic
| | | | - Jaap Keijer
- Human and Animal Physiology, Wageningen University, Wageningen, The Netherlands.
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5
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Berger MM, Luks AM. High Altitude. Semin Respir Crit Care Med 2023; 44:681-695. [PMID: 37816346 DOI: 10.1055/s-0043-1770063] [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: 10/12/2023]
Abstract
With ascent to high altitude, barometric pressure declines, leading to a reduction in the partial pressure of oxygen at every point along the oxygen transport chain from the ambient air to tissue mitochondria. This leads, in turn, to a series of changes over varying time frames across multiple organ systems that serve to maintain tissue oxygen delivery at levels sufficient to prevent acute altitude illness and preserve cognitive and locomotor function. This review focuses primarily on the physiological adjustments and acclimatization processes that occur in the lungs of healthy individuals, including alterations in control of breathing, ventilation, gas exchange, lung mechanics and dynamics, and pulmonary vascular physiology. Because other organ systems, including the cardiovascular, hematologic and renal systems, contribute to acclimatization, the responses seen in these systems, as well as changes in common activities such as sleep and exercise, are also addressed. While the pattern of the responses highlighted in this review are similar across individuals, the magnitude of such responses often demonstrates significant interindividual variability which accounts for subsequent differences in tolerance of the low oxygen conditions in this environment.
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Affiliation(s)
- Marc Moritz Berger
- Department of Anesthesiology and Intensive Care Medicine, University Hospital Essen, University Duisburg-Essen, Essen, Germany
| | - Andrew M Luks
- Division of Pulmonary, Critical Care and Sleep Medicine, University of Washington, Seattle, Washington
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6
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Williamson JL, Linck EB, Bautista E, Smiley A, McGuire JA, Dudley R, Witt CC. Hummingbird blood traits track oxygen availability across space and time. Ecol Lett 2023. [PMID: 37178017 DOI: 10.1111/ele.14235] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 03/20/2023] [Accepted: 04/13/2023] [Indexed: 05/15/2023]
Abstract
Predictable trait variation across environments suggests shared adaptive responses via repeated genetic evolution, phenotypic plasticity or both. Matching of trait-environment associations at phylogenetic and individual scales implies consistency between these processes. Alternatively, mismatch implies that evolutionary divergence has changed the rules of trait-environment covariation. Here we tested whether species adaptation alters elevational variation in blood traits. We measured blood for 1217 Andean hummingbirds of 77 species across a 4600-m elevational gradient. Unexpectedly, elevational variation in haemoglobin concentration ([Hb]) was scale independent, suggesting that physics of gas exchange, rather than species differences, determines responses to changing oxygen pressure. However, mechanisms of [Hb] adjustment did show signals of species adaptation: Species at either low or high elevations adjusted cell size, whereas species at mid-elevations adjusted cell number. This elevational variation in red blood cell number versus size suggests that genetic adaptation to high altitude has changed how these traits respond to shifts in oxygen availability.
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Affiliation(s)
- Jessie L Williamson
- Museum of Southwestern Biology, University of New Mexico, Albuquerque, New Mexico, USA
- Department of Biology, University of New Mexico, Albuquerque, New Mexico, USA
- Cornell Lab of Ornithology, Cornell University, Ithaca, New York, USA
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, New York, USA
- Cornell University Museum of Vertebrates, Cornell University, Ithaca, New York, USA
| | - Ethan B Linck
- Museum of Southwestern Biology, University of New Mexico, Albuquerque, New Mexico, USA
- Department of Biology, University of New Mexico, Albuquerque, New Mexico, USA
| | - Emil Bautista
- Centro de Ornitología y Biodiversidad (CORBIDI), Lima, Peru
| | - Ashley Smiley
- Museum of Southwestern Biology, University of New Mexico, Albuquerque, New Mexico, USA
- Department of Biology, University of New Mexico, Albuquerque, New Mexico, USA
| | - Jimmy A McGuire
- Museum of Vertebrate Zoology, University of California, Berkeley, California, USA
- Department of Integrative Biology, University of California, Berkeley, California, USA
| | - Robert Dudley
- Museum of Vertebrate Zoology, University of California, Berkeley, California, USA
- Department of Integrative Biology, University of California, Berkeley, California, USA
| | - Christopher C Witt
- Museum of Southwestern Biology, University of New Mexico, Albuquerque, New Mexico, USA
- Department of Biology, University of New Mexico, Albuquerque, New Mexico, USA
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7
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Mallet RT, Burtscher J, Pialoux V, Pasha Q, Ahmad Y, Millet GP, Burtscher M. Molecular Mechanisms of High-Altitude Acclimatization. Int J Mol Sci 2023; 24:ijms24021698. [PMID: 36675214 PMCID: PMC9866500 DOI: 10.3390/ijms24021698] [Citation(s) in RCA: 28] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 01/11/2023] [Accepted: 01/13/2023] [Indexed: 01/17/2023] Open
Abstract
High-altitude illnesses (HAIs) result from acute exposure to high altitude/hypoxia. Numerous molecular mechanisms affect appropriate acclimatization to hypobaric and/or normobaric hypoxia and curtail the development of HAIs. The understanding of these mechanisms is essential to optimize hypoxic acclimatization for efficient prophylaxis and treatment of HAIs. This review aims to link outcomes of molecular mechanisms to either adverse effects of acute high-altitude/hypoxia exposure or the developing tolerance with acclimatization. After summarizing systemic physiological responses to acute high-altitude exposure, the associated acclimatization, and the epidemiology and pathophysiology of various HAIs, the article focuses on molecular adjustments and maladjustments during acute exposure and acclimatization to high altitude/hypoxia. Pivotal modifying mechanisms include molecular responses orchestrated by transcription factors, most notably hypoxia inducible factors, and reciprocal effects on mitochondrial functions and REDOX homeostasis. In addition, discussed are genetic factors and the resultant proteomic profiles determining these hypoxia-modifying mechanisms culminating in successful high-altitude acclimatization. Lastly, the article discusses practical considerations related to the molecular aspects of acclimatization and altitude training strategies.
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Affiliation(s)
- Robert T. Mallet
- Department of Physiology and Anatomy, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | - Johannes Burtscher
- Department of Biomedical Sciences, University of Lausanne, CH-1005 Lausanne, Switzerland
- Institute of Sport Sciences, University of Lausanne, CH-1005 Lausanne, Switzerland
| | - Vincent Pialoux
- Inter-University Laboratory of Human Movement Biology EA7424, University Claude Bernard Lyon 1, University of Lyon, FR-69008 Lyon, France
| | - Qadar Pasha
- Institute of Hypoxia Research, New Delhi 110067, India
| | - Yasmin Ahmad
- Defense Institute of Physiology & Allied Sciences (DIPAS), Defense Research & Development Organization(DRDO), New Delhi 110054, India
| | - Grégoire P. Millet
- Department of Biomedical Sciences, University of Lausanne, CH-1005 Lausanne, Switzerland
- Institute of Sport Sciences, University of Lausanne, CH-1005 Lausanne, Switzerland
| | - Martin Burtscher
- Department of Sport Science, University of Innsbruck, A-6020 Innsbruck, Austria
- Austrian Society for Alpine and High-Altitude Medicine, A-6020 Innsbruck, Austria
- Correspondence:
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8
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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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Andresen B, de Marees M, Schiffer T, Bloch W, Suhr F. Skeletal muscle fiber type-specific expressions of mechanosensors integrin-linked kinase, talin, and vinculin and their modulation by loading and environmental conditions in humans. FASEB J 2022; 36:e22458. [PMID: 35867073 DOI: 10.1096/fj.202101377rr] [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: 09/01/2021] [Revised: 07/02/2022] [Accepted: 07/07/2022] [Indexed: 11/11/2022]
Abstract
Mechanosensors control muscle integrity as demonstrated in mice. However, no information is available in human muscle about the distribution of mechanosensors and their adaptations to mechanical loading and environmental conditions (hypoxia). Here, we hypothesized that mechanosensors show fiber-type-specific distributions and that loading and environmental conditions specifically regulate mechanosensors. We randomly subjected 28 healthy males to one of the following groups (n = 7 each) consisting of nine loading sessions within 3 weeks: normoxia moderate (NM), normoxia intensive (NI), hypoxia moderate (HM), and hypoxia intensive (HI). We took six biopsies: pre (T0), 4 h (T1), and 24 h (T2) after the third as well as 4 h (T3), 24 h (T4), and 72 h (T5) after the ninth training session. We analyzed subjects' maximal oxygen consumption (V̇O2 max), maximal power output (Pmax), muscle fiber types and cross-sectional areas (CSA), fiber-type-specific integrin-linked kinase (ILK) localizations as well as ILK, vinculin and talin protein and gene expressions in dependence on loading and environmental conditions. V̇O2 max increased upon NM and HM, Pmax upon all interventions. Fiber types did not change, whereas CSA increased upon NI and HI, but decreased upon HM. ILK showed a type 2-specific fiber type localization. ILK, vinculin, and talin protein and gene expressions differed depending on loading and environmental conditions. Our data demonstrate that mechanosensors show fiber type-specific distributions and that exercise intensities rather than environmental variables influence their profiles in human muscles. These data are the first of their kind in human muscle and indicate that mechanosensors manage the mechanosensing at a fiber-type-specific resolution and that the intensity of mechanical stimulation has a major impact.
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Affiliation(s)
- Bernhard Andresen
- Department of Molecular and Cellular Sport Medicine, German Sport University Cologne, Cologne, Germany
| | - Markus de Marees
- Institute of Sports Medicine and Sports Nutrition, Ruhr University Bochum, Bochum, Germany
| | - Thorsten Schiffer
- Outpatient Clinic for Sports Traumatology and Public Health Consultation, Cologne, Germany
| | - Wilhelm Bloch
- Department of Molecular and Cellular Sport Medicine, German Sport University Cologne, Cologne, Germany
| | - Frank Suhr
- Exercise Physiology Research Group, Department of Movement Sciences, Biomedical Sciences Group, KU Leuven, Leuven, Belgium
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10
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Sharma V, Varshney R, Sethy NK. Human adaptation to high altitude: a review of convergence between genomic and proteomic signatures. Hum Genomics 2022; 16:21. [PMID: 35841113 PMCID: PMC9287971 DOI: 10.1186/s40246-022-00395-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2021] [Accepted: 06/17/2022] [Indexed: 12/29/2022] Open
Abstract
Both genomics- and proteomics-based investigations have identified several essential genes, proteins, and pathways that may facilitate human adaptive genotype/phenotype in a population-specific manner. This comprehensive review provides an up-to-date list of genes and proteins identified for human adaptive responses to high altitudes. Genomics studies for indigenous high-altitude populations like Tibetans, Andeans, Ethiopians, and Sherpas have identified 169 genes under positive natural selection. Similarly, global proteomics studies have identified 258 proteins (± 1.2-fold or more) for Tibetan, Sherpa, and Ladakhi highlanders. The primary biological processes identified for genetic signatures include hypoxia-inducible factor (HIF)-mediated oxygen sensing, angiogenesis, and erythropoiesis. In contrast, major biological processes identified for proteomics signatures include 14–3-3 mediated sirtuin signaling, integrin-linked kinase (ILK), phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT), and integrin signaling. Comparing genetic and protein signatures, we identified 7 common genes/proteins (HBB/hemoglobin subunit beta, TF/serotransferrin, ANGPTL4/angiopoietin-related protein 4, CDC42/cell division control protein 42 homolog, GC/vitamin D-binding protein, IGFBP1/insulin-like growth factor-binding protein 1, and IGFBP2/insulin-like growth factor-binding protein 2) involved in crucial molecular functions like IGF-1 signaling, LXR/RXR activation, ferroptosis signaling, iron homeostasis signaling and regulation of cell cycle. Our combined multi-omics analysis identifies common molecular targets and pathways for human adaptation to high altitude. These observations further corroborate convergent positive selection of hypoxia-responsive molecular pathways in humans and advocate using multi-omics techniques for deciphering human adaptive responses to high altitude.
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Affiliation(s)
- Vandana Sharma
- Peptide and Proteomics Division, Defence Institute of Physiology and Allied Sciences (DIPAS), Defence Research and Development Organisation (DRDO), Lucknow Road, Timarpur, Delhi, 110054, India
| | - Rajeev Varshney
- Peptide and Proteomics Division, Defence Institute of Physiology and Allied Sciences (DIPAS), Defence Research and Development Organisation (DRDO), Lucknow Road, Timarpur, Delhi, 110054, India
| | - Niroj Kumar Sethy
- Peptide and Proteomics Division, Defence Institute of Physiology and Allied Sciences (DIPAS), Defence Research and Development Organisation (DRDO), Lucknow Road, Timarpur, Delhi, 110054, India.
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11
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Ruggiero L, Harrison SWD, Rice CL, McNeil CJ. Neuromuscular fatigability at high altitude: Lowlanders with acute and chronic exposure, and native highlanders. Acta Physiol (Oxf) 2022; 234:e13788. [PMID: 35007386 PMCID: PMC9286620 DOI: 10.1111/apha.13788] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 01/04/2022] [Accepted: 01/05/2022] [Indexed: 01/18/2023]
Abstract
Ascent to high altitude is accompanied by a reduction in partial pressure of inspired oxygen, which leads to interconnected adjustments within the neuromuscular system. This review describes the unique challenge that such an environment poses to neuromuscular fatigability (peripheral, central and supraspinal) for individuals who normally reside near to sea level (SL) (<1000 m; ie, lowlanders) and for native highlanders, who represent the manifestation of high altitude-related heritable adaptations across millennia. Firstly, the effect of acute exposure to high altitude-related hypoxia on neuromuscular fatigability will be examined. Under these conditions, both supraspinal and peripheral fatigability are increased compared with SL. The specific mechanisms contributing to impaired performance are dependent on the exercise paradigm and amount of muscle mass involved. Next, the effect of chronic exposure to high altitude (ie, acclimatization of ~7-28 days) will be considered. With acclimatization, supraspinal fatigability is restored to SL values, regardless of the amount of muscle mass involved, whereas peripheral fatigability remains greater than SL except when exercise involves a small amount of muscle mass (eg, knee extensors). Indeed, when whole-body exercise is involved, peripheral fatigability is not different to acute high-altitude exposure, due to competing positive (haematological and muscle metabolic) and negative (respiratory-mediated) effects of acclimatization on neuromuscular performance. In the final section, we consider evolutionary adaptations of native highlanders (primarily Himalayans of Tibet and Nepal) that may account for their superior performance at altitude and lesser degree of neuromuscular fatigability compared with acclimatized lowlanders, for both single-joint and whole-body exercise.
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Affiliation(s)
- Luca Ruggiero
- Laboratory of Physiomechanics of Locomotion Department of Pathophysiology and Transplantation University of Milan Milan Italy
| | - Scott W. D. Harrison
- School of Kinesiology Faculty of Health Sciences The University of Western Ontario London Ontario Canada
| | - Charles L. Rice
- School of Kinesiology Faculty of Health Sciences The University of Western Ontario London Ontario Canada
- Department of Anatomy and Cell Biology Schulich School of Medicine and Dentistry The University of Western Ontario London Ontario Canada
| | - Chris J. McNeil
- Centre for Heart, Lung & Vascular Health School of Health and Exercise Sciences University of British Columbia Kelowna British Columbia Canada
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12
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Notch Signaling and Cross-Talk in Hypoxia: A Candidate Pathway for High-Altitude Adaptation. Life (Basel) 2022; 12:life12030437. [PMID: 35330188 PMCID: PMC8954738 DOI: 10.3390/life12030437] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Revised: 03/11/2022] [Accepted: 03/11/2022] [Indexed: 12/17/2022] Open
Abstract
Hypoxia triggers complex inter- and intracellular signals that regulate tissue oxygen (O2) homeostasis, adjusting convective O2 delivery and utilization (i.e., metabolism). Human populations have been exposed to high-altitude hypoxia for thousands of years and, in doing so, have undergone natural selection of multiple gene regions supporting adaptive traits. Some of the strongest selection signals identified in highland populations emanate from hypoxia-inducible factor (HIF) pathway genes. The HIF pathway is a master regulator of the cellular hypoxic response, but it is not the only regulatory pathway under positive selection. For instance, regions linked to the highly conserved Notch signaling pathway are also top targets, and this pathway is likely to play essential roles that confer hypoxia tolerance. Here, we explored the importance of the Notch pathway in mediating the cellular hypoxic response. We assessed transcriptional regulation of the Notch pathway, including close cross-talk with HIF signaling, and its involvement in the mediation of angiogenesis, cellular metabolism, inflammation, and oxidative stress, relating these functions to generational hypoxia adaptation.
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13
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HIF-1α Negatively Regulates Irisin Expression Which Involves in Muscle Atrophy Induced by Hypoxia. Int J Mol Sci 2022; 23:ijms23020887. [PMID: 35055073 PMCID: PMC8777935 DOI: 10.3390/ijms23020887] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Revised: 01/08/2022] [Accepted: 01/10/2022] [Indexed: 12/19/2022] Open
Abstract
Exposure to high altitude environment leads to skeletal muscle atrophy. As a hormone secreted by skeletal muscles after exercise, irisin contributes to promoting muscle regeneration and ameliorating skeletal muscle atrophy, but its role in hypoxia-induced skeletal muscle atrophy is still unclear. Our results showed that 4 w of hypoxia exposure significantly reduced body weight and gastrocnemius muscle mass of mice, as well as grip strength and the duration time of treadmill exercise. Hypoxic treatment increased HIF-1α expression and decreased both the circulation level of irisin and its precursor protein FNDC5 expression in skeletal muscle. In in vitro, CoCl2-induced chemical hypoxia and 1% O2 ambient hypoxia both reduced FNDC5, along with the increase in HIF-1α. Moreover, the decline in the area and diameter of myotubes caused by hypoxia were rescued by inhibiting HIF-1α via YC-1. Collectively, our research indicated that FNDC5/irisin was negatively regulated by HIF-1α and could participate in the regulation of muscle atrophy caused by hypoxia.
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14
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Bensaid S, Fabre C, Pawlak-Chaouch M, Cieniewski-Bernard C. Oxygen supplementation to limit hypoxia-induced muscle atrophy in C2C12 myotubes: comparison with amino acid supplement and electrical stimulation. Cell Tissue Res 2022; 387:287-301. [PMID: 35001209 DOI: 10.1007/s00441-021-03492-x] [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: 05/08/2020] [Accepted: 06/21/2021] [Indexed: 11/28/2022]
Abstract
In skeletal muscle, chronic oxygen depletion induces a disturbance leading to muscle atrophy. Mechanical stress (physical exercise) and nutritional supplement therapy are commonly used against loss of muscle mass and undernutrition in hypoxia, while oxygenation therapy is preferentially used to counteract muscle fatigue and exercise intolerance. However, the impact of oxygenation on skeletal muscle cells remains poorly understood, in particular on signalling pathways regulating protein balance. Thus, we investigated the effects of each separated treatment (mechanical stress, nutritional supplementation and oxygenation therapy) on intracellular pathways involved in protein synthesis and degradation that are imbalanced in skeletal muscle cells atrophy resulting from hypoxia. Myotubes under hypoxia were treated by electrical stimulation, amino acids supplement or oxygenation period. Signalling pathways involved in protein synthesis (PI3K-Akt-mTOR) and degradation (FoxO1 and FoxO3a) were investigated, so as autophagy, ubiquitin-proteasome system and myotube morphology. Electrical stimulation and oxygenation treatment resulted in higher myotube diameter, myogenic fusion index and myotubes density until 48 h post-treatment compared to untreated hypoxic myotubes. Both treatments also induced inhibition of FoxO3a and decreased activity of ubiquitin-proteasome system; however, their impact on protein synthesis pathway was specific for each one. Indeed, electrical stimulation impacted upstream proteins to mTOR (i.e., Akt) while oxygenation treatment activated downstream targets of mTOR (i.e., 4E-BP1 and P70S6K). In contrast, amino acid supplementation had very few effects on myotube morphology nor on protein homeostasis. This study demonstrated that electrical stimulation or oxygenation period are two effective treatments to fight against hypoxia-induced muscle atrophy, acting through different molecular adaptations.
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Affiliation(s)
- Samir Bensaid
- Univ. Lille, Univ. Artois, Univ. Littoral Côte D'Opale, URePSSS - Unité de Recherche Pluridisciplinaire Sport Santé Société, F-59000, Lille, France.,CHU Lille, Université de Lille, F-59000, Lille, France
| | - Claudine Fabre
- Univ. Lille, Univ. Artois, Univ. Littoral Côte D'Opale, URePSSS - Unité de Recherche Pluridisciplinaire Sport Santé Société, F-59000, Lille, France
| | - Mehdi Pawlak-Chaouch
- Univ. Lille, Univ. Artois, Univ. Littoral Côte D'Opale, URePSSS - Unité de Recherche Pluridisciplinaire Sport Santé Société, F-59000, Lille, France
| | - Caroline Cieniewski-Bernard
- Univ. Lille, Univ. Artois, Univ. Littoral Côte D'Opale, URePSSS - Unité de Recherche Pluridisciplinaire Sport Santé Société, F-59000, Lille, France.
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15
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Szymczak RK, Grzywacz T, Ziemann E, Sawicka M, Laskowski R. Prolonged Sojourn at Very High Altitude Decreases Sea-Level Anaerobic Performance, Anaerobic Threshold, and Fat Mass. Front Physiol 2021; 12:743535. [PMID: 34675820 PMCID: PMC8523780 DOI: 10.3389/fphys.2021.743535] [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: 07/18/2021] [Accepted: 09/13/2021] [Indexed: 11/22/2022] Open
Abstract
Background: The influence of high altitude on an organism’s physiology depends on the length and the level of hypoxic exposure it experiences. This study aimed to determine the effect of a prolonged sojourn at very high altitudes (above 3,500m) on subsequent sea-level physical performance, body weight, body composition, and hematological parameters. Materials and Methods: Ten alpinists, nine males and one female, with a mean age of 27±4years, participated in the study. All had been on mountaineering expeditions to 7,000m peaks, where they spent 30±1days above 3,500m with their average sojourn at 4,900±60m. Their aerobic and anaerobic performance, body weight, body composition, and hematological parameters were examined at an altitude of 100m within 7days before the expeditions and 7days after they descended below 3,500m. Results: We found a significant (p<0.01) decrease in maximal anaerobic power (MAPWAnT) from 9.9±1.3 to 9.2±1.3W·kg−1, total anaerobic work from 248.1±23.8 to 228.1±20.1J·kg−1, anaerobic threshold from 39.3±8.0 to 27.8±5.6 mlO2·kg−1·min−1, body fat mass from 14.0±3.1 to 11.5±3.3%, and a significant increase (p<0.05) in maximal tidal volume from 3.2 [3.0–3.2] to 3.5 [3.3–3.9] L after their sojourn at very high attitude. We found no significant changes in maximal aerobic power, maximal oxygen uptake, body weight, fat-free mass, total body water, hemoglobin, and hematocrit. Conclusion: A month-long exposure to very high altitude led to impaired sea-level anaerobic performance and anaerobic threshold, increased maximal tidal volume, and depleted body fat mass, but had no effect on maximal aerobic power, maximal oxygen uptake, or hemoglobin and hematocrit levels.
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Affiliation(s)
- Robert K Szymczak
- Department of Emergency Medicine, Faculty of Health Sciences, Medical University of Gdańsk, Gdańsk, Poland
| | - Tomasz Grzywacz
- Department of Sport, Institute of Physical Culture, Kazimierz Wielki University in Bydgoszcz, Bydgoszcz, Poland
| | - Ewa Ziemann
- Department of Athletics, Strength and Conditioning, Poznań University of Physical Education, Poznan, Poland
| | - Magdalena Sawicka
- Department of Neurology, Faculty of Medicine, Medical University of Gdańsk, Gdańsk, Poland
| | - Radosław Laskowski
- Department of Physiology and Biochemistry, Gdańsk University of Physical Education and Sport, Gdańsk, Poland
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16
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Rathor R, Suryakumar G, Singh SN. Diet and redox state in maintaining skeletal muscle health and performance at high altitude. Free Radic Biol Med 2021; 174:305-320. [PMID: 34352371 DOI: 10.1016/j.freeradbiomed.2021.07.024] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 07/14/2021] [Accepted: 07/19/2021] [Indexed: 01/07/2023]
Abstract
High altitude exposure leads to compromised physical performance with considerable weight loss. The major stressor at high altitude is hypobaric hypoxia which leads to disturbance in redox homeostasis. Oxidative stress is a well-known trigger for many high altitude illnesses and regulates several key signaling pathways under stressful conditions. Altered redox homeostasis is considered the prime culprit of high altitude linked skeletal muscle atrophy. Hypobaric hypoxia disturbs redox homeostasis through increased RONS production and compromised antioxidant system. Increased RONS disturbs the cellular homeostasis via multiple ways such as inflammation generation, altered protein anabolic pathways, redox remodeling of RyR1 that contributed to dysregulated calcium homeostasis, enhanced protein degradation pathways via activation calcium-regulated protein, calpain, and apoptosis. Ultimately, all the cellular signaling pathways aggregately result in skeletal muscle atrophy. Dietary supplementation of phytochemicals could become a safe and effective intervention to ameliorate skeletal muscle atrophy and enhance the physical performance of the personnel who are staying at high altitude regions. The present evidence-based review explores few dietary supplementations which regulate several signaling mechanisms and ameliorate hypobaric hypoxia induced muscle atrophy and enhances physical performance. However, a clinical research trial is required to establish proof-of-concept.
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Affiliation(s)
- Richa Rathor
- Defence Institute of Physiology and Allied Sciences, Lucknow Road, Timarpur, New Delhi, 110054, India.
| | - Geetha Suryakumar
- Defence Institute of Physiology and Allied Sciences, Lucknow Road, Timarpur, New Delhi, 110054, India
| | - Som Nath Singh
- Defence Institute of Physiology and Allied Sciences, Lucknow Road, Timarpur, New Delhi, 110054, India
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17
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Lemieux P, Birot O. Altitude, Exercise, and Skeletal Muscle Angio-Adaptive Responses to Hypoxia: A Complex Story. Front Physiol 2021; 12:735557. [PMID: 34552509 PMCID: PMC8450406 DOI: 10.3389/fphys.2021.735557] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Accepted: 08/16/2021] [Indexed: 12/18/2022] Open
Abstract
Hypoxia, defined as a reduced oxygen availability, can be observed in many tissues in response to various physiological and pathological conditions. As a hallmark of the altitude environment, ambient hypoxia results from a drop in the oxygen pressure in the atmosphere with elevation. A hypoxic stress can also occur at the cellular level when the oxygen supply through the local microcirculation cannot match the cells’ metabolic needs. This has been suggested in contracting skeletal myofibers during physical exercise. Regardless of its origin, ambient or exercise-induced, muscle hypoxia triggers complex angio-adaptive responses in the skeletal muscle tissue. These can result in the expression of a plethora of angio-adaptive molecules, ultimately leading to the growth, stabilization, or regression of muscle capillaries. This remarkable plasticity of the capillary network is referred to as angio-adaptation. It can alter the capillary-to-myofiber interface, which represent an important determinant of skeletal muscle function. These angio-adaptive molecules can also be released in the circulation as myokines to act on distant tissues. This review addresses the respective and combined potency of ambient hypoxia and exercise to generate a cellular hypoxic stress in skeletal muscle. The major skeletal muscle angio-adaptive responses to hypoxia so far described in this context will be discussed, including existing controversies in the field. Finally, this review will highlight the molecular complexity of the skeletal muscle angio-adaptive response to hypoxia and identify current gaps of knowledges in this field of exercise and environmental physiology.
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Affiliation(s)
- Pierre Lemieux
- Muscle Health Research Centre, School of Kinesiology and Health Science, York University, Toronto, ON, Canada
| | - Olivier Birot
- Muscle Health Research Centre, School of Kinesiology and Health Science, York University, Toronto, ON, Canada
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18
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Sibomana I, Foose DP, Raymer ML, Reo NV, Karl JP, Berryman CE, Young AJ, Pasiakos SM, Mauzy CA. Urinary Metabolites as Predictors of Acute Mountain Sickness Severity. Front Physiol 2021; 12:709804. [PMID: 34588992 PMCID: PMC8475947 DOI: 10.3389/fphys.2021.709804] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Accepted: 08/19/2021] [Indexed: 11/15/2022] Open
Abstract
Individuals sojourning at high altitude (≥2,500m) often develop acute mountain sickness (AMS). However, substantial unexplained inter-individual variability in AMS severity exists. Untargeted metabolomics assays are increasingly used to identify novel biomarkers of susceptibility to illness, and to elucidate biological pathways linking environmental exposures to health outcomes. This study used untargeted nuclear magnetic resonance (NMR)-based metabolomics to identify urine metabolites associated with AMS severity during high altitude sojourn. Following a 21-day stay at sea level (SL; 55m), 17 healthy males were transported to high altitude (HA; 4,300m) for a 22-day sojourn. AMS symptoms measured twice daily during the first 5days at HA were used to dichotomize participants according to AMS severity: moderate/severe AMS (AMS; n=11) or no/mild AMS (NoAMS; n=6). Urine samples collected on SL day 12 and HA days 1 and 18 were analyzed using proton NMR tools and the data were subjected to multivariate analyses. The SL urinary metabolite profiles were significantly different (p≤0.05) between AMS vs. NoAMS individuals prior to high altitude exposure. Differentially expressed metabolites included elevated levels of creatine and acetylcarnitine, and decreased levels of hypoxanthine and taurine in the AMS vs. NoAMS group. In addition, the levels of two amino acid derivatives (4-hydroxyphenylpyruvate and N-methylhistidine) and two unidentified metabolites (doublet peaks at 3.33ppm and a singlet at 8.20ppm) were significantly different between groups at SL. By HA day 18, the differences in urinary metabolites between AMS and NoAMS participants had largely resolved. Pathway analysis of these differentially expressed metabolites indicated that they directly or indirectly play a role in energy metabolism. These observations suggest that alterations in energy metabolism before high altitude exposure may contribute to AMS susceptibility at altitude. If validated in larger cohorts, these markers could inform development of a non-invasive assay to screen individuals for AMS susceptibility prior to high altitude sojourn.
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Affiliation(s)
- Isaie Sibomana
- Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, MD, United States
- Air Force Research Laboratory, 711th Human Performance Wing, Wright-Patterson AFB, Dayton, OH, United States
| | - Daniel P. Foose
- Department of Computer Science and Engineering, Wright State University, Dayton, OH, United States
| | - Michael L. Raymer
- Department of Computer Science and Engineering, Wright State University, Dayton, OH, United States
| | - Nicholas V. Reo
- Boonshoft School of Medicine, Wright State University, Dayton, OH, United States
| | - J. Philip Karl
- Military Nutrition Division, U.S. Army Research Institute of Environmental Medicine, Natick, MA, United States
| | - Claire E. Berryman
- Military Nutrition Division, U.S. Army Research Institute of Environmental Medicine, Natick, MA, United States
- Department of Nutrition, Food, and Exercise Sciences, Florida State University, Tallahassee, FL, United States
- Oak Ridge Institute of Science and Education, Belcamp, MD, United States
| | - Andrew J. Young
- Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, MD, United States
- Military Nutrition Division, U.S. Army Research Institute of Environmental Medicine, Natick, MA, United States
- Oak Ridge Institute of Science and Education, Belcamp, MD, United States
| | - Stefan M. Pasiakos
- Military Nutrition Division, U.S. Army Research Institute of Environmental Medicine, Natick, MA, United States
| | - Camilla A. Mauzy
- Air Force Research Laboratory, 711th Human Performance Wing, Wright-Patterson AFB, Dayton, OH, United States
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19
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Brizzolari A, Dei Cas M, Cialoni D, Marroni A, Morano C, Samaja M, Paroni R, Rubino FM. High-Throughput Griess Assay of Nitrite and Nitrate in Plasma and Red Blood Cells for Human Physiology Studies under Extreme Conditions. Molecules 2021; 26:molecules26154569. [PMID: 34361720 PMCID: PMC8348835 DOI: 10.3390/molecules26154569] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Revised: 07/23/2021] [Accepted: 07/26/2021] [Indexed: 12/21/2022] Open
Abstract
The metabolism of nitric oxide plays an increasingly interesting role in the physiological response of the human body to extreme environmental conditions, such as underwater, in an extremely cold climate, and at low oxygen concentrations. Field studies need the development of analytical methods to measure nitrite and nitrate in plasma and red blood cells with high requirements of accuracy, precision, and sensitivity. An optimized spectrophotometric Griess method for nitrite–nitrate affords sensitivity in the low millimolar range and precision within ±2 μM for both nitrite and nitrate, requiring 100 μL of scarcely available plasma sample or less than 50 μL of red blood cells. A scheduled time-efficient procedure affords measurement of as many as 80 blood samples, with combined nitrite and nitrate measurement in plasma and red blood cells. Performance and usefulness were tested in pilot studies that use blood fractions deriving from subjects who dwelt in an Antarctica scientific station and on breath-holding and scuba divers who performed training at sea and in a land-based deep pool facility. The method demonstrated adequate to measure low basal concentrations of nitrite and high production of nitrate as a consequence of water column pressure-triggered vasodilatation in deep-water divers.
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Affiliation(s)
- Andrea Brizzolari
- Laboratory for Analytical Toxicology and Metabonomics, Department of Health Sciences, Università degli Studi di Milano, v. A. di Rudinì 8, 20142 Milan, Italy;
- DAN Europe Research Division, Contrada Padune, 64026 Roseto degli Abruzzi, Italy; (D.C.); (A.M.)
| | - Michele Dei Cas
- Laboratory of Clinical Chemistry and Mass Spectrometry, Department of Health Sciences, Università degli Studi di Milano, v. A. di Rudinì 8, 20142 Milan, Italy; (M.D.C.); (C.M.); (R.P.)
| | - Danilo Cialoni
- DAN Europe Research Division, Contrada Padune, 64026 Roseto degli Abruzzi, Italy; (D.C.); (A.M.)
| | - Alessandro Marroni
- DAN Europe Research Division, Contrada Padune, 64026 Roseto degli Abruzzi, Italy; (D.C.); (A.M.)
| | - Camillo Morano
- Laboratory of Clinical Chemistry and Mass Spectrometry, Department of Health Sciences, Università degli Studi di Milano, v. A. di Rudinì 8, 20142 Milan, Italy; (M.D.C.); (C.M.); (R.P.)
| | - Michele Samaja
- Laboratory of Biochemistry, Department of Health Sciences, Università degli Studi di Milano, v. A. di Rudinì 8, 20142 Milan, Italy;
| | - Rita Paroni
- Laboratory of Clinical Chemistry and Mass Spectrometry, Department of Health Sciences, Università degli Studi di Milano, v. A. di Rudinì 8, 20142 Milan, Italy; (M.D.C.); (C.M.); (R.P.)
| | - Federico Maria Rubino
- DAN Europe Research Division, Contrada Padune, 64026 Roseto degli Abruzzi, Italy; (D.C.); (A.M.)
- Correspondence:
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20
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Galli GLJ, Ruhr IM, Crossley J, Crossley DA. The Long-Term Effects of Developmental Hypoxia on Cardiac Mitochondrial Function in Snapping Turtles. Front Physiol 2021; 12:689684. [PMID: 34262478 PMCID: PMC8273549 DOI: 10.3389/fphys.2021.689684] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 06/03/2021] [Indexed: 01/05/2023] Open
Abstract
It is well established that adult vertebrates acclimatizing to hypoxic environments undergo mitochondrial remodeling to enhance oxygen delivery, maintain ATP, and limit oxidative stress. However, many vertebrates also encounter oxygen deprivation during embryonic development. The effects of developmental hypoxia on mitochondrial function are likely to be more profound, because environmental stress during early life can permanently alter cellular physiology and morphology. To this end, we investigated the long-term effects of developmental hypoxia on mitochondrial function in a species that regularly encounters hypoxia during development-the common snapping turtle (Chelydra serpentina). Turtle eggs were incubated in 21% or 10% oxygen from 20% of embryonic development until hatching, and both cohorts were subsequently reared in 21% oxygen for 8 months. Ventricular mitochondria were isolated, and mitochondrial respiration and reactive oxygen species (ROS) production were measured with a microrespirometer. Compared to normoxic controls, juvenile turtles from hypoxic incubations had lower Leak respiration, higher P:O ratios, and reduced rates of ROS production. Interestingly, these same attributes occur in adult vertebrates that acclimatize to hypoxia. We speculate that these adjustments might improve mitochondrial hypoxia tolerance, which would be beneficial for turtles during breath-hold diving and overwintering in anoxic environments.
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Affiliation(s)
- Gina L. J. Galli
- Faculty of Biology, Medicine, and Health, School of Medical Sciences, The University of Manchester, Manchester, United Kingdom
| | - Ilan M. Ruhr
- Faculty of Biology, Medicine, and Health, School of Medical Sciences, The University of Manchester, Manchester, United Kingdom
| | - Janna Crossley
- Developmental Integrative Biology Research Group, Department of Biological Sciences, University of North Texas, Denton, TX, United States
| | - Dane A. Crossley
- Developmental Integrative Biology Research Group, Department of Biological Sciences, University of North Texas, Denton, TX, United States
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21
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Slivka D, Dumke C, Hailes W, Ruby B. Impact of Hypoxic Exercise Recovery on Skeletal Muscle Glycogen and Gene Expression. High Alt Med Biol 2021; 22:300-307. [PMID: 34142871 DOI: 10.1089/ham.2021.0028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Slivka, Dustin, Charles Dumke, Walter Hailes, and Brent Ruby. Impact of hypoxic exercise recovery on skeletal muscle glycogen and gene expression. High Alt Med Biol. 22:300-307, 2021. Background: The impact of altitude during recovery from exercise is largely unknown. The purpose of this study was to determine the acute gene response and muscle glycogen re-synthesis after exercise when exposed to simulated high altitude during recovery. Materials and Methods: Twelve male participants (age, 25 ± 2 years; height, 178 ± 7 cm; weight, 78.8 ± 7.8 kg; VO2peak, 4.25 ± 0.59 l/min; Wpeak 307 ± 44 W; and body fat, 13.1% ± 1.2%) completed two trials (random order), which consisted of cycling for 90 minutes in laboratory conditions and then recovering for 6 hours in laboratory conditions (975 m; normoxia) or at a high simulated altitude (5,000 m; hypoxia). Results: Skeletal muscle biopsies from the vastus lateralis were obtained before exercise, after exercise, and 6 hours after exercise for the measurement of metabolic gene expression and muscle glycogen. Muscle glycogen decreased with exercise (61% ± 13%, p < 0.05) and increased with recovery (78% ± 35%, p < 0.05) with no difference between trials (p > 0.05). Hypoxia-inducible factor (HIF)-1α, HIF-2α, optic atrophy gene 1 (OPA-1), mitofusin 2 (MFN-2), and peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC-1α) gene expression were suppressed after altitude exposure (p < 0.05), while mitochondrial fission 1 protein (FIS-1), phosphofructokinase (PFK), Cytochrome c oxidase (COX), and hexokinase (HK) were unaffected by altitude exposure (p > 0.05). Conclusions: High-altitude exposure during recovery from exercise inhibits gene expression associated with mitochondrial development without affecting muscle glycogen re-synthesis.
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Affiliation(s)
- Dustin Slivka
- School of Health and Kinesiology, University of Nebraska at Omaha, Omaha, Nebraska, USA
| | - Charles Dumke
- School of Integrative Physiology and Athletic Training, University of Montana, Missoula, Montana, USA
| | - Walter Hailes
- School of Integrative Physiology and Athletic Training, University of Montana, Missoula, Montana, USA
| | - Brent Ruby
- School of Integrative Physiology and Athletic Training, University of Montana, Missoula, Montana, USA
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22
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Malgoyre A, Prola A, Meunier A, Chapot R, Serrurier B, Koulmann N, Bigard X, Sanchez H. Endurance Is Improved in Female Rats After Living High-Training High Despite Alterations in Skeletal Muscle. Front Sports Act Living 2021; 3:663857. [PMID: 34124658 PMCID: PMC8193088 DOI: 10.3389/fspor.2021.663857] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 04/12/2021] [Indexed: 11/29/2022] Open
Abstract
Altitude camps are used during the preparation of endurance athletes to improve performance based on the stimulation of erythropoiesis by living at high altitude. In addition to such whole-body adaptations, studies have suggested that high-altitude training increases mitochondrial mass, but this has been challenged by later studies. Here, we hypothesized that living and training at high altitude (LHTH) improves mitochondrial efficiency and/or substrate utilization. Female rats were exposed and trained in hypoxia (simulated 3,200 m) for 5 weeks (LHTH) and compared to sedentary rats living in hypoxia (LH) or normoxia (LL) or those that trained in normoxia (LLTL). Maximal aerobic velocity (MAV) improved with training, independently of hypoxia, whereas the time to exhaustion, performed at 65% of MAV, increased both with training (P = 0.009) and hypoxia (P = 0.015), with an additive effect of the two conditions. The distance run was 7.98 ± 0.57 km in LHTH vs. 6.94 ± 0.51 in LLTL (+15%, ns). The hematocrit increased >20% with hypoxia (P < 0.001). The increases in mitochondrial mass and maximal oxidative capacity with endurance training were blunted by combination with hypoxia (−30% for citrate synthase, P < 0.01, and −23% for Vmax glut−succ, P < 0.001 between LHTH and LLTL). A similar reduction between the LHTH and LLTL groups was found for maximal respiration with pyruvate (−29%, P < 0.001), for acceptor-control ratio (−36%, hypoxia effect, P < 0.001), and for creatine kinase efficiency (−48%, P < 0.01). 3-hydroxyl acyl coenzyme A dehydrogenase was not altered by hypoxia, whereas maximal respiration with Palmitoyl-CoA specifically decreased. Overall, our results show that mitochondrial adaptations are not involved in the improvement of submaximal aerobic performance after LHTH, suggesting that the benefits of altitude camps in females relies essentially on other factors, such as the transitory elevation of hematocrit, and should be planned a few weeks before competition and not several months.
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Affiliation(s)
- Alexandra Malgoyre
- Département des Environnements Opérationnels, Institut de Recherche Biomédicale des Armées, Brétigny-sur-Orge, France.,Laboratoire de Biologie de l'Exercice pour la Performance et la Santé, Université Evry, Université Paris Saclay, Evry, France
| | - Alexandre Prola
- Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Adelie Meunier
- Département des Environnements Opérationnels, Institut de Recherche Biomédicale des Armées, Brétigny-sur-Orge, France
| | - Rachel Chapot
- Département des Environnements Opérationnels, Institut de Recherche Biomédicale des Armées, Brétigny-sur-Orge, France
| | - Bernard Serrurier
- Département des Environnements Opérationnels, Institut de Recherche Biomédicale des Armées, Brétigny-sur-Orge, France
| | - Nathalie Koulmann
- Département des Environnements Opérationnels, Institut de Recherche Biomédicale des Armées, Brétigny-sur-Orge, France.,Laboratoire de Biologie de l'Exercice pour la Performance et la Santé, Université Evry, Université Paris Saclay, Evry, France.,Ecole du Val de Grâce, Paris, France
| | - Xavier Bigard
- Département des Environnements Opérationnels, Institut de Recherche Biomédicale des Armées, Brétigny-sur-Orge, France.,Ecole du Val de Grâce, Paris, France
| | - Hervé Sanchez
- Département des Environnements Opérationnels, Institut de Recherche Biomédicale des Armées, Brétigny-sur-Orge, France
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23
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Modulation of lung cytoskeletal remodeling, RXR based metabolic cascades and inflammation to achieve redox homeostasis during extended exposures to lowered pO 2. Apoptosis 2021; 26:431-446. [PMID: 34002323 DOI: 10.1007/s10495-021-01679-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/10/2021] [Indexed: 10/21/2022]
Abstract
Extended exposure to low pO2 has multiple effects on signaling cascades. Despite multiple exploratory studies, omics studies elucidating the signaling cascades essential for surviving extended low pO2 exposures are lacking. In this study, we simulated low pO2 (PB = 40 kPa; 7620 m) exposure in male Sprague-Dawley rats for 3, 7 and 14 days. Redox stress assays and proteomics based network biology were performed using lungs and plasma. We observed that redox homeostasis was achieved after day 3 of exposure. We investigated the causative events for this. Proteo-bioinformatics analysis revealed STAT3 to be upstream of lung cytoskeletal processes and systemic lipid metabolism (RXR) derived inflammatory processes, which were the key events. Thus, during prolonged low pO2 exposure, particularly those involving slowly decreasing pressures, redox homeostasis is achieved but energy metabolism is perturbed and this leads to an immune/inflammatory signaling impetus after third day of exposure. We found that an interplay of lung cytoskeletal elements, systemic energy metabolism and inflammatory proteins aid in achieving redox homeostasis and surviving extended low pO2 exposures. Qualitative perturbations to cytoskeletal stability and innate immunity/inflammation were also observed during extended low pO2 exposure in humans exposed to 14,000 ft for 7, 14 and 21 days.
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24
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Ferri A, Yan X, Kuang J, Granata C, Oliveira RSF, Hedges CP, Lima-Silva AE, Billaut F, Bishop DJ. Fifteen days of moderate normobaric hypoxia does not affect mitochondrial function, and related genes and proteins, in healthy men. Eur J Appl Physiol 2021; 121:2323-2336. [PMID: 33988746 DOI: 10.1007/s00421-021-04706-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Accepted: 04/28/2021] [Indexed: 11/28/2022]
Abstract
PURPOSE To investigate within the one study potential molecular and cellular changes associated with mitochondrial biogenesis following 15 days of exposure to moderate hypoxia. METHODS Eight males underwent a muscle biopsy before and after 15 days of hypoxia exposure (FiO2 = 0.140-0.154; ~ 2500-3200 m) in a hypoxic hotel. Mitochondrial respiration, citrate synthase (CS) activity, and the content of genes and proteins associated with mitochondrial biogenesis were investigated. RESULTS Our main findings were the absence of significant changes in the mean values of CS activity, mitochondrial respiration in permeabilised fibers, or the content of genes and proteins associated with mitochondrial biogenesis, after 15 days of moderate normobaric hypoxia. CONCLUSION Our data provide evidence that 15 days of moderate normobaric hypoxia have negligible influence on skeletal muscle mitochondrial content and function, or genes and proteins content associated with mitochondrial biogenesis, in young recreationally active males. However, the increase in mitochondrial protease LON content after hypoxia exposure suggests the possibility of adaptations to optimise respiratory chain function under conditions of reduced O2 availability.
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Affiliation(s)
- Alessandra Ferri
- Institute for Health and Sport, Victoria University, Melbourne, VIC, Australia
| | - Xu Yan
- Institute for Health and Sport, Victoria University, Melbourne, VIC, Australia
| | - Jujiao Kuang
- Institute for Health and Sport, Victoria University, Melbourne, VIC, Australia
| | - Cesare Granata
- Institute for Health and Sport, Victoria University, Melbourne, VIC, Australia.,Department of Diabetes, Central Clinical School, Monash University, Alfred Medical Research and Education Precinct, Melbourne, VIC, Australia
| | | | | | - Adriano E Lima-Silva
- Human Performance Research Group, Federal University of Technology-Parana (UTFPR), Curitiba, Brazil
| | - Francois Billaut
- Institute for Health and Sport, Victoria University, Melbourne, VIC, Australia.,Département de Kinésiologie, Université Laval, Québec, Canada
| | - David J Bishop
- Institute for Health and Sport, Victoria University, Melbourne, VIC, Australia.
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25
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Kolodziej F, O’Halloran KD. Re-Evaluating the Oxidative Phenotype: Can Endurance Exercise Save the Western World? Antioxidants (Basel) 2021; 10:609. [PMID: 33921022 PMCID: PMC8071436 DOI: 10.3390/antiox10040609] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 04/06/2021] [Accepted: 04/10/2021] [Indexed: 01/16/2023] Open
Abstract
Mitochondria are popularly called the "powerhouses" of the cell. They promote energy metabolism through the tricarboxylic acid (TCA) cycle and oxidative phosphorylation, which in contrast to cytosolic glycolysis are oxygen-dependent and significantly more substrate efficient. That is, mitochondrial metabolism provides substantially more cellular energy currency (ATP) per macronutrient metabolised. Enhancement of mitochondrial density and metabolism are associated with endurance training, which allows for the attainment of high relative VO2 max values. However, the sedentary lifestyle and diet currently predominant in the Western world lead to mitochondrial dysfunction. Underdeveloped mitochondrial metabolism leads to nutrient-induced reducing pressure caused by energy surplus, as reduced nicotinamide adenine dinucleotide (NADH)-mediated high electron flow at rest leads to "electron leak" and a chronic generation of superoxide radicals (O2-). Chronic overload of these reactive oxygen species (ROS) damages cell components such as DNA, cell membranes, and proteins. Counterintuitively, transiently generated ROS during exercise contributes to adaptive reduction-oxidation (REDOX) signalling through the process of cellular hormesis or "oxidative eustress" defined by Helmut Sies. However, the unaccustomed, chronic oxidative stress is central to the leading causes of mortality in the 21st century-metabolic syndrome and the associated cardiovascular comorbidities. The endurance exercise training that improves mitochondrial capacity and the protective antioxidant cellular system emerges as a universal intervention for mitochondrial dysfunction and resultant comorbidities. Furthermore, exercise might also be a solution to prevent ageing-related degenerative diseases, which are caused by impaired mitochondrial recycling. This review aims to break down the metabolic components of exercise and how they translate to athletic versus metabolically diseased phenotypes. We outline a reciprocal relationship between oxidative metabolism and inflammation, as well as hypoxia. We highlight the importance of oxidative stress for metabolic and antioxidant adaptation. We discuss the relevance of lactate as an indicator of critical exercise intensity, and inferring from its relationship with hypoxia, we suggest the most appropriate mode of exercise for the case of a lost oxidative identity in metabolically inflexible patients. Finally, we propose a reciprocal signalling model that establishes a healthy balance between the glycolytic/proliferative and oxidative/prolonged-ageing phenotypes. This model is malleable to adaptation with oxidative stress in exercise but is also susceptible to maladaptation associated with chronic oxidative stress in disease. Furthermore, mutations of components involved in the transcriptional regulatory mechanisms of mitochondrial metabolism may lead to the development of a cancerous phenotype, which progressively presents as one of the main causes of death, alongside the metabolic syndrome.
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Affiliation(s)
- Filip Kolodziej
- Department of Physiology, School of Medicine, College of Medicine & Health, University College Cork, T12 XF62 Cork, Ireland;
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26
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Sharma S, Singh Y, Sandhir R, Singh S, Ganju L, Kumar B, Varshney R. Mitochondrial DNA mutations contribute to high altitude pulmonary edema via increased oxidative stress and metabolic reprogramming during hypobaric hypoxia. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2021; 1862:148431. [PMID: 33862004 DOI: 10.1016/j.bbabio.2021.148431] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 12/13/2020] [Revised: 03/27/2021] [Accepted: 04/07/2021] [Indexed: 10/21/2022]
Abstract
High altitude pulmonary edema (HAPE) is experienced by non-acclimatized sea level individuals on exposure to high altitude hypoxic conditions. Available evidence suggests that genetic factors and perturbed mitochondrial redox status may play an important role in HAPE pathophysiology. However, the precise mechanism has not been fully understood. In the present study, sequencing of mitochondrial DNA (mtDNA) from HAPE subjects and acclimatized controls was performed to identify pathogenic mutations and to determine their role in HAPE. Hypobaric hypoxia induced oxidative stress and metabolic alterations were also assessed in HAPE subjects. mtDNA copy number, mitochondrial oxidative phosphorylation (mtOXPHOS) activity, mitochondrial biogenesis were measured to determine mitochondrial functions. The data revealed that the mutations in Complex I genes affects the secondary structure of protein in HAPE subjects. Further, increased oxidative stress during hypobaric hypoxia, reduced mitochondrial biogenesis and mtOXPHOS activity induced metabolic reprogramming appears to contribute to mitochondrial dysfunctions in HAPE individuals. Haplogroup analysis suggests that mtDNA haplogroup H2a2a1 has potential contribution in the pathobiology of HAPE in lowlanders. This study also suggests contribution of altered mitochondrial functions in HAPE susceptibility.
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Affiliation(s)
- Swati Sharma
- Defence Institute of Physiology and Allied Sciences (DIPAS), Defence R&D Organization (DRDO), Lucknow Road, Timarpur, Delhi 110054, India; Department of Biochemistry, Basic Medical Sciences Block II, Panjab University, Chandigarh 160014, India
| | - Yamini Singh
- Defence Institute of Physiology and Allied Sciences (DIPAS), Defence R&D Organization (DRDO), Lucknow Road, Timarpur, Delhi 110054, India.
| | - Rajat Sandhir
- Department of Biochemistry, Basic Medical Sciences Block II, Panjab University, Chandigarh 160014, India
| | - Sayar Singh
- Defence Institute of Physiology and Allied Sciences (DIPAS), Defence R&D Organization (DRDO), Lucknow Road, Timarpur, Delhi 110054, India
| | - Lilly Ganju
- Defence Institute of Physiology and Allied Sciences (DIPAS), Defence R&D Organization (DRDO), Lucknow Road, Timarpur, Delhi 110054, India
| | - Bhuvnesh Kumar
- Defence Institute of Physiology and Allied Sciences (DIPAS), Defence R&D Organization (DRDO), Lucknow Road, Timarpur, Delhi 110054, India
| | - Rajeev Varshney
- Defence Institute of Physiology and Allied Sciences (DIPAS), Defence R&D Organization (DRDO), Lucknow Road, Timarpur, Delhi 110054, India
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27
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Fan JL, Wu TY, Lovering AT, Nan L, Bang WL, Kayser B. Differential Brain and Muscle Tissue Oxygenation Responses to Exercise in Tibetans Compared to Han Chinese. Front Physiol 2021; 12:617954. [PMID: 33716766 PMCID: PMC7943468 DOI: 10.3389/fphys.2021.617954] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Accepted: 01/18/2021] [Indexed: 11/13/2022] Open
Abstract
The Tibetans’ better aerobic exercise capacity at altitude remains ill-understood. We tested the hypothesis that Tibetans display better muscle and brain tissue oxygenation during exercise in hypoxia. Using near-infrared spectrometry (NIRS) to provide indices of tissue oxygenation, we measured oxy- and deoxy-hemoglobin ([O2Hb] and [HHb], respectively) responses of the vastus lateralis muscle and the right prefrontal cortex in ten Han Chinese and ten Tibetans during incremental cycling to exhaustion in a pressure-regulated chamber at simulated sea-level (air at 1 atm: normobaric normoxia) and 5,000 m (air at 0.5 atm: hypobaric hypoxia). Hypoxia reduced aerobic capacity by ∼22% in both groups (d = 0.8, p < 0.001 vs. normoxia), while Tibetans consistently outperformed their Han Chinese counterpart by ∼32% in normoxia and hypoxia (d = 1.0, p = 0.008). We found cerebral [O2Hb] was higher in Tibetans at normoxic maximal effort compared Han (p = 0.001), while muscle [O2Hb] was not different (p = 0.240). Hypoxic exercise lowered muscle [O2Hb] in Tibetans by a greater extent than in Han (interaction effect: p < 0.001 vs. normoxic exercise). Muscle [O2Hb] was lower in Tibetans when compared to Han during hypoxic exercise (d = 0.9, p = 0.003), but not during normoxic exercise (d = 0.4, p = 0.240). Muscle [HHb] was not different between the two groups during normoxic and hypoxic exercise (p = 0.778). Compared to Han, our findings revealed a higher brain tissue oxygenation in Tibetans during maximal exercise in normoxia, but lower muscle tissue oxygenation during exercise in hypoxia. This would suggest that the Tibetans privileged oxygenation of the brain at the expense of that of the muscle.
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Affiliation(s)
- Jui-Lin Fan
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Tian Yi Wu
- Research Center for High Altitude Medicine, Tibet University Medical College, Lhasa, China.,National Key Laboratory of High Altitude Medicine, Xining, China
| | - Andrew T Lovering
- Department of Human Physiology, University of Oregon, Eugene, OR, United States
| | - Liya Nan
- National Key Laboratory of High Altitude Medicine, Xining, China
| | - Wang Liang Bang
- National Key Laboratory of High Altitude Medicine, Xining, China
| | - Bengt Kayser
- Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland
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28
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McKenna HT, O'Brien KA, Fernandez BO, Minnion M, Tod A, McNally BD, West JA, Griffin JL, Grocott MP, Mythen MG, Feelisch M, Murray AJ, Martin DS. Divergent trajectories of cellular bioenergetics, intermediary metabolism and systemic redox status in survivors and non-survivors of critical illness. Redox Biol 2021; 41:101907. [PMID: 33667994 PMCID: PMC7937570 DOI: 10.1016/j.redox.2021.101907] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 02/06/2021] [Accepted: 02/16/2021] [Indexed: 02/01/2023] Open
Abstract
Background Numerous pathologies result in multiple-organ failure, which is thought to be a direct consequence of compromised cellular bioenergetic status. Neither the nature of this phenotype nor its relevance to survival are well understood, limiting the efficacy of modern life-support. Methods To explore the hypothesis that survival from critical illness relates to changes in cellular bioenergetics, we combined assessment of mitochondrial respiration with metabolomic, lipidomic and redox profiling in skeletal muscle and blood, at multiple timepoints, in 21 critically ill patients and 12 reference patients. Results We demonstrate an end-organ cellular phenotype in critical illness, characterized by preserved total energetic capacity, greater coupling efficiency and selectively lower capacity for complex I and fatty acid oxidation (FAO)-supported respiration in skeletal muscle, compared to health. In survivors, complex I capacity at 48 h was 27% lower than in non-survivors (p = 0.01), but tended to increase by day 7, with no such recovery observed in non-survivors. By day 7, survivors’ FAO enzyme activity was double that of non-survivors (p = 0.048), in whom plasma triacylglycerol accumulated. Increases in both cellular oxidative stress and reductive drive were evident in early critical illness compared to health. Initially, non-survivors demonstrated greater plasma total antioxidant capacity but ultimately higher lipid peroxidation compared to survivors. These alterations were mirrored by greater levels of circulating total free thiol and nitrosated species, consistent with greater reductive stress and vascular inflammation, in non-survivors compared to survivors. In contrast, no clear differences in systemic inflammatory markers were observed between the two groups. Conclusion Critical illness is associated with rapid, specific and coordinated alterations in the cellular respiratory machinery, intermediary metabolism and redox response, with different trajectories in survivors and non-survivors. Unravelling the cellular and molecular foundation of human resilience may enable the development of more effective life-support strategies.
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Affiliation(s)
- Helen T McKenna
- Division of Surgery and Interventional Science, University College London, Royal Free Hospital, London, NW3 2QG, UK; Intensive Care Unit, Royal Free Hospital, London, NW3 2QG, UK; Peninsula Medical School, University of Plymouth, John Bull Building, Derriford, Plymouth, PL6 8BU, UK
| | - Katie A O'Brien
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, CB2 3EG, UK
| | - Bernadette O Fernandez
- Clinical & Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, SO16 6YD, UK
| | - Magdalena Minnion
- Clinical & Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, SO16 6YD, UK
| | - Adam Tod
- Clinical & Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, SO16 6YD, UK
| | - Ben D McNally
- Department of Biochemistry and the Cambridge Systems Biology Centre, University of Cambridge, CB2 1GA, UK
| | - James A West
- Cambridge Institute of Therapeutic Immunology and Infectious Disease, Department of Medicine, Jeffrey Cheah Biomedical Centre, University of Cambridge, CB2 0RE, UK
| | - Julian L Griffin
- Department of Biochemistry and the Cambridge Systems Biology Centre, University of Cambridge, CB2 1GA, UK; Section of Biomolecular Medicine, Department of Digestion, Metabolism and Reproduction, Imperial College London, SW7 2AZ, UK
| | - Michael P Grocott
- Anaesthesia Perioperative and Critical Care Research Group, Southampton National Institute of Health Research Biomedical Research Centre, University Hospital Southampton, SO16 6YD, UK
| | - Michael G Mythen
- University College London Hospitals and Great Ormond Street, National Institute of Health Research Biomedical Research Centres, London, WC1N 1EH, UK
| | - Martin Feelisch
- Clinical & Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, SO16 6YD, UK; Anaesthesia Perioperative and Critical Care Research Group, Southampton National Institute of Health Research Biomedical Research Centre, University Hospital Southampton, SO16 6YD, UK
| | - Andrew J Murray
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, CB2 3EG, UK.
| | - Daniel S Martin
- Division of Surgery and Interventional Science, University College London, Royal Free Hospital, London, NW3 2QG, UK; Intensive Care Unit, Royal Free Hospital, London, NW3 2QG, UK; Peninsula Medical School, University of Plymouth, John Bull Building, Derriford, Plymouth, PL6 8BU, UK
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29
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Abstract
The syndrome of critical illness is a complex physiological stressor that can be triggered by diverse pathologies. It is widely believed that organ dysfunction and death result from bioenergetic failure caused by inadequate cellular oxygen supply. Teleologically, life has evolved to survive in the face of stressors by undergoing a suite of adaptive changes. Adaptation not only comprises alterations in systemic physiology but also involves molecular reprogramming within cells. The concept of cellular adaptation in critically ill patients is a matter of contention in part because medical interventions mask underlying physiology, creating the artificial construct of "chronic critical illness," without which death would be imminent. Thus far, the intensive care armamentarium has not targeted cellular metabolism to preserve a temporary equilibrium but instead attempts to normalize global oxygen and substrate delivery. Here, we review adaptations to hypoxia that have been demonstrated in cellular models and in human conditions associated with hypoxia, including the hypobaric hypoxia of high altitude, the intrauterine low-oxygen environment, and adult myocardial hibernation. Common features include upregulation of glycolytic ATP production, enhancement of respiratory efficiency, downregulation of mitochondrial density, and suppression of energy-consuming processes. We argue that these innate cellular adaptations to hypoxia represent potential avenues for intervention that have thus far remained untapped by intensive care medicine.
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Affiliation(s)
- Helen T McKenna
- Division of Surgery and Interventional Science, University College London, London, United Kingdom.,Royal Free Intensive Care Unit, Royal Free Hospital, London, United Kingdom
| | - Andrew J Murray
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Daniel S Martin
- Royal Free Intensive Care Unit, Royal Free Hospital, London, United Kingdom.,Peninsula Medical School, University of Plymouth, Plymouth, United Kingdom
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30
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Hattersley J, Wilson AJ, Gifford R, Facer-Childs J, Stoten O, Cobb R, Thake CD, Reynolds RM, Woods D, Imray C. A comparison of the metabolic effects of sustained strenuous activity in polar environments on men and women. Sci Rep 2020; 10:13912. [PMID: 32807833 PMCID: PMC7431584 DOI: 10.1038/s41598-020-70296-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Accepted: 06/24/2020] [Indexed: 01/05/2023] Open
Abstract
This study investigates differences in pre- to post-expedition energy expenditure, substrate utilisation and body composition, between the all-male Spear17 (SP-17) and all-female Ice Maiden (IM) transantarctic expeditions (IM: N = 6, 61 days, 1700 km; SP-17: N = 5, 67 days, 1750 km). Energy expenditure and substrate utilisation were measured by a standardised 36 h calorimetry protocol; body composition was determined using air displacement plethysmography. Energy balance calculation were used to assess the physical challenge. There was difference in the daily energy expenditure (IM: 4,939 kcal day−1; SP-17: 6,461 kcal day−1, p = 0.004); differences related to physical activity were small, but statistically significant (IM = 2,282 kcal day−1; SP-17 = 3,174 kcal day−1; p = 0.004). Bodyweight loss was modest (IM = 7.8%, SP-17 = 6.5%; p > 0.05) as was fat loss (IM = 30.4%, SP-17 = 40.4%; p > 0.05). Lean tissue weight change was statistically significant (IM = − 2.5%, SP-17 = + 1.0%; p = 0.05). No difference was found in resting or sleeping energy expenditure, normalised to lean tissue weight (p > 0.05); nor in energy expenditure when exercising at 80, 100 and 120 steps min−1, normalised to body weight (p > 0.05). Similarly, no difference was found in the change in normalised substrate utilisation for any of the activities (p > 0.05). Analysis suggested that higher daily energy expenditures for the men in Spear-17 was the result of higher physical demands resulting in a reduced demand for energy to thermoregulate compared to the women in Ice Maiden. The lack of differences between men and women in the change in energy expenditure and substrate utilisation, suggests no sex difference in response to exposure to extreme environments.
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Affiliation(s)
- John Hattersley
- Coventry NIHR CRF Human Metabolic Research Unit, University Hospitals Coventry and Warwickshire NHS Trust, Coventry, CV2 2DX, UK. .,School of Engineering, University of Warwick, Coventry, CV4 7AL, USA. .,Faculty of Health and Life Sciences, Coventry University, Coventry, UK.
| | - Adrian J Wilson
- Coventry NIHR CRF Human Metabolic Research Unit, University Hospitals Coventry and Warwickshire NHS Trust, Coventry, CV2 2DX, UK.,Department of Physics, University of Warwick, Coventry, CV4 7AL, UK
| | - Rob Gifford
- University/British Heart Foundation Centre for Cardiovascular Science, Queen's Medical Research Institute, University of Edinburgh, Edinburgh, UK.,Research and Clinical Innovation, Royal Centre for Defence Medicine, Birmingham, UK
| | - Jamie Facer-Childs
- Institute of Child Health, University College London, London, WC1N 1EH, UK
| | - Oliver Stoten
- Emergency Department, Royal Bournemouth Hospital, Bournemouth, BH7 7DW, UK
| | - Rinn Cobb
- Performance, Nutrition and Dietetic Consulting, pnd consulting.co.uk, Middlesbrough, UK
| | - C Doug Thake
- Faculty of Health and Life Sciences, Coventry University, Coventry, UK
| | - Rebecca M Reynolds
- University/British Heart Foundation Centre for Cardiovascular Science, Queen's Medical Research Institute, University of Edinburgh, Edinburgh, UK
| | - David Woods
- Research and Clinical Innovation, Royal Centre for Defence Medicine, Birmingham, UK.,Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, UK.,Northumbria and Newcastle NHS Trusts, Wansbeck General and Royal Victoria Infirmary, Newcastle, UK
| | - Chris Imray
- Coventry NIHR CRF Human Metabolic Research Unit, University Hospitals Coventry and Warwickshire NHS Trust, Coventry, CV2 2DX, UK.,Faculty of Health and Life Sciences, Coventry University, Coventry, UK.,Department of Vascular and Renal Transplant Surgery, University Hospitals Coventry and Warwickshire NHS Trust, Coventry, CV2 2DX, UK
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31
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Feng S, Ma J, Long K, Zhang J, Qiu W, Li Y, Jin L, Wang X, Jiang A, Liu L, Xiao W, Li X, Tang Q, Li M. Comparative microRNA Transcriptomes in Domestic Goats Reveal Acclimatization to High Altitude. Front Genet 2020; 11:809. [PMID: 32849809 PMCID: PMC7411263 DOI: 10.3389/fgene.2020.00809] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2020] [Accepted: 07/06/2020] [Indexed: 01/30/2023] Open
Abstract
High-altitude acclimatization is a representative example of vertebrates' acclimatization to harsh and extreme environments. Previous studies reported sufficient evidence for a molecular genetic basis of high-altitude acclimatization, and genomic patterns of genetic variation among populations and species have been widely elucidated in recent years. However, understanding of the miRNA role in high-altitude acclimatization have lagged behind, especially in non-model species. To investigate miRNA expression alterations of goats that were induced by high-altitude stress, we performed comparative miRNA transcriptome analysis on six hypoxia-sensitive tissues (heart, kidney, liver, lung, skeletal muscle, and spleen) in two goat populations from distinct altitudes (600 and 3000 m). We obtained the expression value of 1391 mature miRNAs and identified 138 differentially expressed (DE) miRNAs between high and low altitudes. Combined with tissue specificity analysis, we illustrated alterations of expression levels among altitudes and tissues, and found that there were coexisting tissue-specific and -conserved mechanisms for hypoxia acclimatization. Notably, the interplay between DE miRNA and DE target genes strongly indicated post-transcriptional regulation in the hypoxia inducible factor 1, insulin, and p53 signaling pathways, which might play significant roles in high-altitude acclimatization in domestic goats. It's also worth noting that we experimentally confirmed miR-106a-5p to have a negative regulation effect on angiogenesis by directly targeting FLT-1. These results provide insight into the complicated miRNA expression patterns and regulatory mechanisms of high-altitude acclimatization in domestic goats.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | - Qianzi Tang
- Institute of Animal Genetics and Breeding, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, China
| | - Mingzhou Li
- Institute of Animal Genetics and Breeding, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, China
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Stienen GJM. Early adjustments in mitochondrial structure and function in skeletal muscle to high altitude: design and rationale of the first study from the Kilimanjaro Biobank. Biophys Rev 2020; 12:793-798. [PMID: 32572680 DOI: 10.1007/s12551-020-00710-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 06/16/2020] [Indexed: 12/21/2022] Open
Abstract
The physiological acclimatisation and adaptation processes in skeletal muscle at high altitude are of high medical and social relevance not only to understand limitations in physical performance at high altitude but also to understand the consequences of hypoxemia and tissue hypoxia in critically ill patients. Of particular importance in these processes are the alterations in content and function of mitochondria and myoglobin. The majority of studies on oxygen delivery to the tissues and utilisation by the cellular metabolism at high altitude were performed after prolonged stay at high altitude and in altitude-adapted highlanders. However, these studies do not provide insight in the sequence of events during the physiological acclimatisation and adaptation processes. Therefore, it is important to identify the early alterations in structure and function of the major determinants of the oxygen transport via myoglobin and oxygen utilisation by the mitochondria in skeletal muscle at high altitude. To achieve this goal, it is of interest to collect, analyse and compare quadriceps muscle biopsies and venous blood samples of climbers, guides and porters before and after climbing Mount Kilimanjaro and in participants of the Kilimanjaro Marathon before and after the run. The samples will be carefully documented and stored in the Kilimanjaro Biobank and will be made available to other research groups.
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Affiliation(s)
- G J M Stienen
- Department of Physiology, Kilimanjaro Christian Medical University College, PO Box 2240, Moshi, Tanzania. .,Department of Physiology, Amsterdam UMC, Amsterdam Cardiovascular Sciences, Vrije Universiteit, Amsterdam, the Netherlands.
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Wang W, Mukai K, Takahashi K, Ohmura H, Takahashi T, Hatta H, Kitaoka Y. Short-term hypoxic training increases monocarboxylate transporter 4 and phosphofructokinase activity in Thoroughbreds. Physiol Rep 2020; 8:e14473. [PMID: 32512646 PMCID: PMC7279979 DOI: 10.14814/phy2.14473] [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: 04/27/2020] [Revised: 05/03/2020] [Accepted: 05/09/2020] [Indexed: 12/18/2022] Open
Abstract
The aim of this study was to investigate effects of short-term hypoxic training on lactate metabolism in the gluteus medius muscle of Thoroughbreds. Using crossover design (3 months washout), eight Thoroughbred horses were trained for 2 weeks in normoxia (FI O2 = 21%) and hypoxia (FI O2 = 18%) each. They ran at 95% maximal oxygen consumption (V̇O2max ) on a treadmill inclined at 6% for 2 min (3 days/week) measured under normoxia. Before and after each training period, all horses were subjected to an incremental exercise test (IET) under normoxia. Following the 2-week trainings, V̇O2max in IET increased significantly under both oxygen conditions. The exercise duration in IET increased significantly only after hypoxic training. The monocarboxylate transporter (MCT) 1 protein levels remained unchanged after training under both oxygen conditions, whereas MCT4 protein levels increased significantly after training in hypoxia but not after training in normoxia. Phosphofructokinase activity increased significantly only after hypoxic training, whereas cytochrome c oxidase activity increased significantly only after normoxic training. Our results suggest that hypoxic training efficiently enhances glycolytic capacity and levels of the lactate transporter protein MCT4, which facilitates lactate efflux from the skeletal muscle.
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Affiliation(s)
- Wenxin Wang
- Department of Human SciencesKanagawa UniversityKanagawaJapan
| | - Kazutaka Mukai
- Equine Research InstituteJapan Racing AssociationTochigiJapan
| | - Kenya Takahashi
- Department of Sports SciencesThe University of TokyoTokyoJapan
| | - Hajime Ohmura
- Equine Research InstituteJapan Racing AssociationTochigiJapan
| | | | - Hideo Hatta
- Department of Sports SciencesThe University of TokyoTokyoJapan
| | - Yu Kitaoka
- Department of Human SciencesKanagawa UniversityKanagawaJapan
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Rood K, Lopez V, La Frano MR, Fiehn O, Zhang L, Blood AB, Wilson SM. Gestational Hypoxia and Programing of Lung Metabolism. Front Physiol 2019; 10:1453. [PMID: 31849704 PMCID: PMC6895135 DOI: 10.3389/fphys.2019.01453] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Accepted: 11/11/2019] [Indexed: 12/12/2022] Open
Abstract
Gestational hypoxia is a risk factor in the development of pulmonary hypertension in the newborn and other sequela, however, the mechanisms associated with the disease remain poorly understood. This review highlights disruption of metabolism by antenatal high altitude hypoxia and the impact this has on pulmonary hypertension in the newborn with discussion of model organisms and human populations. There is particular emphasis on modifications in glucose and lipid metabolism along with alterations in mitochondrial function. Additional focus is placed on increases in oxidative stress and the progression of pulmonary vascular disease in the newborn and on the need for further exploration using a combination of contemporary and classical approaches.
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Affiliation(s)
- Kristiana Rood
- Lawrence D. Longo MD Center for Perinatal Biology, School of Medicine, Loma Linda University, Loma Linda, CA, United States
| | - Vanessa Lopez
- Lawrence D. Longo MD Center for Perinatal Biology, School of Medicine, Loma Linda University, Loma Linda, CA, United States
| | - Michael R La Frano
- Department of Food Science and Nutrition, Center for Health Research, California Polytechnic State University, San Luis Obispo, CA, United States.,Center for Health Research, California Polytechnic State University, San Luis Obispo, CA, United States
| | - Oliver Fiehn
- NIH West Coast Metabolomics Center, University of California, Davis, Davis, CA, United States.,Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA, United States
| | - Lubo Zhang
- Lawrence D. Longo MD Center for Perinatal Biology, School of Medicine, Loma Linda University, Loma Linda, CA, United States
| | - Arlin B Blood
- Lawrence D. Longo MD Center for Perinatal Biology, School of Medicine, Loma Linda University, Loma Linda, CA, United States
| | - Sean M Wilson
- Lawrence D. Longo MD Center for Perinatal Biology, School of Medicine, Loma Linda University, Loma Linda, CA, United States
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35
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Lankford HV. High Altitude Deterioration: A Historical Essay. Wilderness Environ Med 2019; 30:328-333. [DOI: 10.1016/j.wem.2019.04.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Revised: 04/14/2019] [Accepted: 04/26/2019] [Indexed: 11/25/2022]
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36
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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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Dünnwald T, Gatterer H, Faulhaber M, Arvandi M, Schobersberger W. Body Composition and Body Weight Changes at Different Altitude Levels: A Systematic Review and Meta-Analysis. Front Physiol 2019; 10:430. [PMID: 31057421 PMCID: PMC6477059 DOI: 10.3389/fphys.2019.00430] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Accepted: 03/28/2019] [Indexed: 12/12/2022] Open
Abstract
Changes in body composition and weight loss frequently occur when humans are exposed to hypoxic environments. The mechanisms thought to be responsible for these changes are increased energy expenditure resulting from increased basal metabolic rate and/or high levels of physical activity, inadequate energy intake, fluid loss as well as gastrointestinal malabsorption. The severity of hypoxia, the duration of exposure as well as the level of physical activity also seem to play crucial roles in the final outcome. On one hand, excessive weight loss in mountaineers exercising at high altitudes may affect performance and climbing success. On the other, hypoxic conditioning is presumed to have an important therapeutic potential in weight management programs in overweight/obese people, especially in combination with exercise. In this regard, it is important to define the hypoxia effect on both body composition and weight change. The purpose of this study is to define, through the use of meta-analysis, the extent of bodyweight -and body composition changes within the three internationally classified altitude levels (moderate altitude: 1500–3500 m; high altitude: 3500–5300 m; extreme altitude: >5300 m), with emphasis on physical activity, nutrition, duration of stay and type of exposure.
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Affiliation(s)
- Tobias Dünnwald
- Institute for Sports Medicine, Alpine Medicine & Health Tourism, UMIT - University for Health Sciences, Medical Informatics and Technology, Hall in Tirol, Austria
| | - Hannes Gatterer
- Institute of Mountain Emergency Medicine, EURAC Research, Bolzano, Italy
| | - Martin Faulhaber
- Department of Sport Science, University of Innsbruck, Innsbruck, Austria
| | - Marjan Arvandi
- Institute of Public Health, Medical Decision Making and HTA, Department for Public Health, Medical Decision Making and Health Technology Assessment, UMIT - University for Health Sciences, Medical Informatics and Technology, Hall in Tirol, Austria
| | - Wolfgang Schobersberger
- Institute for Sports Medicine, Alpine Medicine & Health Tourism, UMIT - University for Health Sciences, Medical Informatics and Technology, Hall in Tirol, Austria.,Tirol Kliniken GmbH Innsbruck, Innsbruck, Austria
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38
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Anesthetists (and Physicians) at Altitude. Int Anesthesiol Clin 2019. [PMID: 29521789 DOI: 10.1097/aia.0000000000000184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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39
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Horscroft JA, O'Brien KA, Clark AD, Lindsay RT, Steel AS, Procter NEK, Devaux J, Frenneaux M, Harridge SDR, Murray AJ. Inorganic nitrate, hypoxia, and the regulation of cardiac mitochondrial respiration-probing the role of PPARα. FASEB J 2019; 33:7563-7577. [PMID: 30870003 PMCID: PMC6529343 DOI: 10.1096/fj.201900067r] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Dietary inorganic nitrate prevents aspects of cardiac mitochondrial dysfunction induced by hypoxia, although the mechanism is not completely understood. In both heart and skeletal muscle, nitrate increases fatty acid oxidation capacity, and in the latter case, this involves up-regulation of peroxisome proliferator-activated receptor (PPAR)α expression. Here, we investigated whether dietary nitrate modifies mitochondrial function in the hypoxic heart in a PPARα-dependent manner. Wild-type (WT) mice and mice without PPARα (Ppara−/−) were given water containing 0.7 mM NaCl (control) or 0.7 mM NaNO3 for 35 d. After 7 d, mice were exposed to normoxia or hypoxia (10% O2) for the remainder of the study. Mitochondrial respiratory function and metabolism were assessed in saponin-permeabilized cardiac muscle fibers. Environmental hypoxia suppressed mass-specific mitochondrial respiration and additionally lowered the proportion of respiration supported by fatty acid oxidation by 18% (P < 0.001). This switch away from fatty acid oxidation was reversed by nitrate treatment in hypoxic WT but not Ppara−/− mice, indicating a PPARα-dependent effect. Hypoxia increased hexokinase activity by 33% in all mice, whereas lactate dehydrogenase activity increased by 71% in hypoxic WT but not Ppara−/− mice. Our findings indicate that PPARα plays a key role in mediating cardiac metabolic remodeling in response to both hypoxia and dietary nitrate supplementation.—Horscroft, J. A., O’Brien, K. A., Clark, A. D., Lindsay, R. T., Steel, A. S., Procter, N. E. K., Devaux, J., Frenneaux, M., Harridge, S. D. R., Murray, A. J. Inorganic nitrate, hypoxia, and the regulation of cardiac mitochondrial respiration—probing the role of PPARα.
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Affiliation(s)
- James A Horscroft
- Department of Physiology, Development, and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Katie A O'Brien
- Department of Physiology, Development, and Neuroscience, University of Cambridge, Cambridge, United Kingdom.,Centre for Human and Applied Physiological Sciences, King's College London, London, United Kingdom; and
| | - Anna D Clark
- Department of Physiology, Development, and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Ross T Lindsay
- Department of Physiology, Development, and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Alice Strang Steel
- Department of Physiology, Development, and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Nathan E K Procter
- Bob Champion Research and Education Building, University of East Anglia, Norwich, United Kingdom
| | - Jules Devaux
- Department of Physiology, Development, and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Michael Frenneaux
- Bob Champion Research and Education Building, University of East Anglia, Norwich, United Kingdom
| | - Stephen D R Harridge
- Centre for Human and Applied Physiological Sciences, King's College London, London, United Kingdom; and
| | - Andrew J Murray
- Department of Physiology, Development, and Neuroscience, University of Cambridge, Cambridge, United Kingdom
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40
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Hattersley J, Wilson AJ, Gifford RM, Cobb R, Thake CD, Reynolds RM, Woods DR, Imray CHE. Pre- to postexpedition changes in the energy usage of women undertaking sustained expeditionary polar travel. J Appl Physiol (1985) 2019; 126:681-690. [DOI: 10.1152/japplphysiol.00792.2018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
This paper reports the metabolic energy changes in six women who made the first unsupported traverse of Antarctica, covering a distance of 1,700 km in 61 days, hauling sledges weighing up to 80 kg. Pre- and postexpedition, measurements of energy expenditure and substrate utilization were made on all six members of the expedition over a 36-h period in a whole body calorimeter. During the study, subjects were fed an isocaloric diet: 50% carbohydrate, 35% fat, and 15% protein. The experimental protocol contained pre- and postexpedition measurement, including periods of sleep, rest, and three periods of standardized stepping exercise at 80, 100, and 120 steps/min. A median (interquartile range) decrease in the lean and fat weight of the subjects of 1.4 (1.0) and 4.4 (1.8) kg, respectively (P < 0.05) was found, using air-displacement plethysmography. No statistically significant difference was found between pre- and postexpedition values for sleeping or resting metabolic rate, nor for diet-induced thermogenesis. A statistically significant difference was found in energy expenditure between the pre- and postexpedition values for exercise at 100 [4.7 (0.23) vs. 4.4 (0.29), P < 0.05] and 120 [5.7 (0.46) vs. 5.5 (0.43), P < 0.05] steps/min; a difference that disappeared when the metabolic rate values were normalized to body weight. The group was well matched for the measures studied. Whereas a physiological change in weight was seen, the lack of change in metabolic rate measures supports a view that women appropriately nourished and well prepared can undertake polar expeditions with a minimal metabolic energy consequence. NEW & NOTEWORTHY This is the first study on the metabolic energy consequences for women undertaking expeditionary polar travel. The results show that participant selection gave a “well-matched” group, particularly during exercise. Notwithstanding this, individual differences were observed and explored. The results show that appropriately selected, trained, and nourished women can undertake such expeditions with no change in their metabolic energy requirements during rest or while undertaking moderate exercise over a sustained period of time.
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Affiliation(s)
- John Hattersley
- Coventry National Institute for Health Research, Clinical Research Facility, Human Metabolic Research Unit, University Hospitals Coventry and Warwickshire, National Health Service Trust, Coventry, United Kingdom
- School of Engineering, University of Warwick, Coventry, United Kingdom
| | - Adrian J. Wilson
- Coventry National Institute for Health Research, Clinical Research Facility, Human Metabolic Research Unit, University Hospitals Coventry and Warwickshire, National Health Service Trust, Coventry, United Kingdom
- Department of Physics, University of Warwick, Coventry, United Kingdom
| | - Robert M. Gifford
- University/British Heart Foundation Centre for Cardiovascular Science, Queen’s Medical Research Institute, University of Edinburgh, Edinburgh, United Kingdom
- Research and Clinical Innovation, Royal Centre for Defence Medicine, Birmingham, United Kingdom
| | - Rin Cobb
- Performance, Nutrition and Dietetic Consulting, Birmingham, United Kingdom
| | - C. Doug Thake
- Faculty of Health and Life Sciences, Coventry University, Coventry, United Kingdom
| | - Rebecca M. Reynolds
- University/British Heart Foundation Centre for Cardiovascular Science, Queen’s Medical Research Institute, University of Edinburgh, Edinburgh, United Kingdom
| | - David R. Woods
- Research and Clinical Innovation, Royal Centre for Defence Medicine, Birmingham, United Kingdom
- Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, United Kingdom
- Northumbria and Newcastle National Health Service Trusts, Wansbeck General and Royal Victoria Infirmary, Newcastle, United Kingdom
| | - Christopher H. E. Imray
- Coventry National Institute for Health Research, Clinical Research Facility, Human Metabolic Research Unit, University Hospitals Coventry and Warwickshire, National Health Service Trust, Coventry, United Kingdom
- Faculty of Health and Life Sciences, Coventry University, Coventry, United Kingdom
- Department of Vascular and Renal Transplant Surgery, University Hospitals Coventry and Warwickshire, National Health Service Trust, Coventry, United Kingdom
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41
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Kurhaluk N, Lukash O, Nosar V, Portnychenko A, Portnichenko V, Wszedybyl-Winklewska M, Winklewski PJ. Liver mitochondrial respiratory plasticity and oxygen uptake evoked by cobalt chloride in rats with low and high resistance to extreme hypobaric hypoxia. Can J Physiol Pharmacol 2019; 97:392-399. [PMID: 30681909 DOI: 10.1139/cjpp-2018-0642] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
High-altitude intolerance and consequently high-altitude sickness, is difficult to predict. Liver is an essential organ in glucose and lipid metabolism, and may play key role in the adaptation to high altitude. In response to extreme high altitude, mitochondrial respiration exhibits changes in substrate metabolism, mitochondrial electron transport chain activity, and respiratory coupling. We determined the cobalt chloride (CoCl2) effects on liver mitochondrial plasticity and oxygen uptake in rats with low resistance (LR) and high resistance (HR) to extreme hypobaric hypoxia. The polarographic method proposed by Chance and Williams was used as a simple and effective tool to trace mitochondrial functionality and oxygen consumption. HR rats had more efficient processes of NADH- and FAD-generated mitochondrial oxidation. CoCl2 promoted more efficient NADH-generated and diminished less efficient FAD-generated mitochondrial respiratory reactions in HR rats. CoCl2 diminished both aerobic and anaerobic processes in LR rats. Glutamate and pyruvate substrates of NADH-generated mitochondrial pathways were highly affected by CoCl2. Red blood cells acted as cobalt depots in HR and LR rats. We have unveiled several mechanisms leading to differentiated mitochondrial respiratory responses to hypobaric hypoxia in LR and HR rats. Our study strongly supports the existence of adaptive liver mitochondrial plasticity to extreme hypoxia.
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Affiliation(s)
- Natalia Kurhaluk
- a Department of Physiology, Institute of Biology and Environment Protection, Pomeranian University of Slupsk, Słupsk, Poland
| | - Oleksaner Lukash
- b Department of Ecology and Nature Protection, T.G. Shevchenko National University "Chernihiv Colehium", Chernihiv, Ukraine
| | - Valentina Nosar
- c Department of Hypoxia, Bogomoletz Institute of Physiology, National Academy of Sciences of Ukraine, Kiev, Ukraine; International Centre for Medical, Astronomical and Ecological Research, National Academy of Sciences of Ukraine, Kiev, Ukraine
| | - Alla Portnychenko
- c Department of Hypoxia, Bogomoletz Institute of Physiology, National Academy of Sciences of Ukraine, Kiev, Ukraine; International Centre for Medical, Astronomical and Ecological Research, National Academy of Sciences of Ukraine, Kiev, Ukraine
| | - Volodymyr Portnichenko
- c Department of Hypoxia, Bogomoletz Institute of Physiology, National Academy of Sciences of Ukraine, Kiev, Ukraine; International Centre for Medical, Astronomical and Ecological Research, National Academy of Sciences of Ukraine, Kiev, Ukraine
| | | | - Pawel J Winklewski
- d Department of Human Physiology, Faculty of Health Sciences, Medical University of Gdansk, Gdansk, Poland.,e Department of Clinical Anatomy and Physiology, Faculty of Health Sciences, Pomeranian University of Slupsk, Slupsk, Poland
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42
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He S, Li J, Wang J, Zhang Y. Hypoxia exposure alleviates impaired muscular metabolism, glucose tolerance, and aerobic capacity in apelin-knockout mice. FEBS Open Bio 2019; 9:498-509. [PMID: 30868058 PMCID: PMC6396165 DOI: 10.1002/2211-5463.12587] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Revised: 12/13/2018] [Accepted: 12/21/2018] [Indexed: 12/12/2022] Open
Abstract
High altitude hypoxia adaptation can improve glucose tolerance in people with metabolic syndrome and type 2 diabetes (T2D). Apelin is an endogenous ligand of the G protein-coupled receptor APJ and has possible roles in energy metabolism. Apelin-null mice have been reported to exhibit impaired insulin sensitivity, which can be reversed by supplementation of exogenous apelin. Here, we examined the effects of 4 weeks' intermittent hypoxia exposure on physiological and biochemical variables in apelin knockout (KO) mice. Apelin KO mice exhibited decreased expression of substrate metabolism-associated genes/proteins, impaired glucose tolerance, and reduced exercise capacity compared to wild-type mice, and all of these effects were rescued by hypoxia. These findings suggest that hypoxia intervention may possibly be able to alleviate metabolic conditions caused by genetic defects.
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Affiliation(s)
- Shiyi He
- School of Sport ScienceBeijing Sport UniversityChina
| | - Junping Li
- School of Sport ScienceBeijing Sport UniversityChina
| | - Jianxiong Wang
- Faculty of Health, Engineering and SciencesUniversity of Southern QueenslandToowoombaAustralia
| | - Ying Zhang
- School of Sport ScienceBeijing Sport UniversityChina
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43
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Burtscher M, Niedermeier M, Burtscher J, Pesta D, Suchy J, Strasser B. Preparation for Endurance Competitions at Altitude: Physiological, Psychological, Dietary and Coaching Aspects. A Narrative Review. Front Physiol 2018; 9:1504. [PMID: 30425646 PMCID: PMC6218926 DOI: 10.3389/fphys.2018.01504] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Accepted: 10/05/2018] [Indexed: 01/14/2023] Open
Abstract
It was the Summer Olympic Games 1968 held in Mexico City (2,300 m) that required scientists and coaches to cope with the expected decline of performance in endurance athletes and to establish optimal preparation programs for competing at altitude. From that period until now many different recommendations for altitude acclimatization in advance of an altitude competition were proposed, ranging from several hours to several weeks. Those recommendations are mostly based on the separate consideration of the physiology of acclimatization, psychological issues, performance changes, logistical or individual aspects, but there is no review considering all these aspects in their entirety. Therefore, the present work primarily focusses on the period of altitude sojourn prior to the competition at altitude based on physiological and psychological aspects complemented by nutritional and sports practical considerations.
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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
| | - Martin Niedermeier
- Department of Sport Science, University of Innsbruck, Innsbruck, Austria
| | - Johannes Burtscher
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Dominik Pesta
- Institute for Clinical Diabetology, German Diabetes Center, Leibniz Institute for Diabetes Research at Heinrich Heine University, Düsseldorf, Germany.,German Center for Diabetes Research, München-Neuherberg, Germany
| | - Jiri Suchy
- Faculty of Physical Education and Sport, Charles University, Prague, Czechia
| | - Barbara Strasser
- Department of Epidemiology and Preventive Medicine, University of Regensburg, Regensburg, Germany.,Medical School, Sigmund Freud University, Vienna, Austria
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44
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Chaillou T. Skeletal Muscle Fiber Type in Hypoxia: Adaptation to High-Altitude Exposure and Under Conditions of Pathological Hypoxia. Front Physiol 2018; 9:1450. [PMID: 30369887 PMCID: PMC6194176 DOI: 10.3389/fphys.2018.01450] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Accepted: 09/24/2018] [Indexed: 01/16/2023] Open
Abstract
Skeletal muscle is able to modify its size, and its metabolic/contractile properties in response to a variety of stimuli, such as mechanical stress, neuronal activity, metabolic and hormonal influences, and environmental factors. A reduced oxygen availability, called hypoxia, has been proposed to induce metabolic adaptations and loss of mass in skeletal muscle. In addition, several evidences indicate that muscle fiber-type composition could be affected by hypoxia. The main purpose of this review is to explore the adaptation of skeletal muscle fiber-type composition to exposure to high altitude (ambient hypoxia) and under conditions of pathological hypoxia, including chronic obstructive pulmonary disease (COPD), chronic heart failure (CHF) and obstructive sleep apnea syndrome (OSAS). The muscle fiber-type composition of both adult animals and humans is not markedly altered during chronic exposure to high altitude. However, the fast-to-slow fiber-type transition observed in hind limb muscles during post-natal development is impaired in growing rats exposed to severe altitude. A slow-to-fast transition in fiber type is commonly found in lower limb muscles from patients with COPD and CHF, whereas a transition toward a slower fiber-type profile is often found in the diaphragm muscle in these two pathologies. A slow-to-fast transformation in fiber type is generally observed in the upper airway muscles in rodent models of OSAS. The factors potentially responsible for the adaptation of fiber type under these hypoxic conditions are also discussed in this review. The impaired locomotor activity most likely explains the changes in fiber type composition in growing rats exposed to severe altitude. Furthermore, chronic inactivity and muscle deconditioning could result in the slow-to-fast fiber-type conversion in lower limb muscles during COPD and CHF, while the factors responsible for the adaptation of muscle fiber type during OSAS remain hypothetical. Finally, the role played by cellular hypoxia, hypoxia-inducible factor-1 alpha (HIF-1α), and other molecular regulators in the adaptation of muscle fiber-type composition is described in response to high altitude exposure and conditions of pathological hypoxia.
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Affiliation(s)
- Thomas Chaillou
- School of Health Sciences, Örebro University, Örebro, Sweden
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45
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O'Brien KA, Horscroft JA, Devaux J, Lindsay RT, Steel AS, Clark AD, Philp A, Harridge SDR, Murray AJ. PPARα-independent effects of nitrate supplementation on skeletal muscle metabolism in hypoxia. Biochim Biophys Acta Mol Basis Dis 2018; 1865:844-853. [PMID: 30055294 PMCID: PMC6414754 DOI: 10.1016/j.bbadis.2018.07.027] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Revised: 07/19/2018] [Accepted: 07/20/2018] [Indexed: 12/20/2022]
Abstract
Hypoxia is a feature of many disease states where convective oxygen delivery is impaired, and is known to suppress oxidative metabolism. Acclimation to hypoxia thus requires metabolic remodelling, however hypoxia tolerance may be aided by dietary nitrate supplementation. Nitrate improves tissue oxygenation and has been shown to modulate skeletal muscle tissue metabolism via transcriptional changes, including through the activation of peroxisome proliferator-activated receptor alpha (PPARα), a master regulator of fat metabolism. Here we investigated whether nitrate supplementation protects skeletal muscle mitochondrial function in hypoxia and whether PPARα is required for this effect. Wild-type and PPARα knockout (PPARα−/−) mice were supplemented with sodium nitrate via the drinking water or sodium chloride as control, and exposed to environmental hypoxia (10% O2) or normoxia for 4 weeks. Hypoxia suppressed mitochondrial respiratory function in mouse soleus, an effect partially alleviated through nitrate supplementation, but occurring independently of PPARα. Specifically, hypoxia resulted in 26% lower mass specific fatty acid-supported LEAK respiration and 23% lower pyruvate-supported oxidative phosphorylation capacity. Hypoxia also resulted in 24% lower citrate synthase activity in mouse soleus, possibly indicating a loss of mitochondrial content. These changes were not seen, however, in hypoxic mice when supplemented with dietary nitrate, indicating a nitrate dependent preservation of mitochondrial function. Moreover, this was observed in both wild-type and PPARα−/− mice. Our results support the notion that nitrate supplementation can aid hypoxia tolerance and indicate that nitrate can exert effects independently of PPARα. Hypoxic exposure suppresses mitochondrial respiration in mouse skeletal muscle. Loss of citrate synthase activity suggests decreased mitochondrial content. Dietary inorganic nitrate partially protects against hypoxia-induced changes. Nitrate protects independently of peroxisome proliferator-activated receptor α.
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Affiliation(s)
- Katie A O'Brien
- Department of Physiology, Development & Neuroscience, University of Cambridge, Cambridge, UK; Centre for Human and Applied Physiological Sciences, King's College London, London, UK.
| | - James A Horscroft
- Department of Physiology, Development & Neuroscience, University of Cambridge, Cambridge, UK
| | - Jules Devaux
- Department of Physiology, Development & Neuroscience, University of Cambridge, Cambridge, UK
| | - Ross T Lindsay
- Department of Physiology, Development & Neuroscience, University of Cambridge, Cambridge, UK
| | - Alice Strang Steel
- Department of Physiology, Development & Neuroscience, University of Cambridge, Cambridge, UK
| | - Anna D Clark
- Department of Physiology, Development & Neuroscience, University of Cambridge, Cambridge, UK
| | - Andrew Philp
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, UK; Diabetes and Metabolism Division, Garvan Institute of Medical Research, Darlinghurst, Australia
| | - Stephen D R Harridge
- Centre for Human and Applied Physiological Sciences, King's College London, London, UK
| | - Andrew J Murray
- Department of Physiology, Development & Neuroscience, University of Cambridge, Cambridge, UK.
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Viscor G, Torrella JR, Corral L, Ricart A, Javierre C, Pages T, Ventura JL. Physiological and Biological Responses to Short-Term Intermittent Hypobaric Hypoxia Exposure: From Sports and Mountain Medicine to New Biomedical Applications. Front Physiol 2018; 9:814. [PMID: 30038574 PMCID: PMC6046402 DOI: 10.3389/fphys.2018.00814] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Accepted: 06/11/2018] [Indexed: 12/14/2022] Open
Abstract
In recent years, the altitude acclimatization responses elicited by short-term intermittent exposure to hypoxia have been subject to renewed attention. The main goal of short-term intermittent hypobaric hypoxia exposure programs was originally to improve the aerobic capacity of athletes or to accelerate the altitude acclimatization response in alpinists, since such programs induce an increase in erythrocyte mass. Several model programs of intermittent exposure to hypoxia have presented efficiency with respect to this goal, without any of the inconveniences or negative consequences associated with permanent stays at moderate or high altitudes. Artificial intermittent exposure to normobaric hypoxia systems have seen a rapid rise in popularity among recreational and professional athletes, not only due to their unbeatable cost/efficiency ratio, but also because they help prevent common inconveniences associated with high-altitude stays such as social isolation, nutritional limitations, and other minor health and comfort-related annoyances. Today, intermittent exposure to hypobaric hypoxia is known to elicit other physiological response types in several organs and body systems. These responses range from alterations in the ventilatory pattern to modulation of the mitochondrial function. The central role played by hypoxia-inducible factor (HIF) in activating a signaling molecular cascade after hypoxia exposure is well known. Among these targets, several growth factors that upregulate the capillary bed by inducing angiogenesis and promoting oxidative metabolism merit special attention. Applying intermittent hypobaric hypoxia to promote the action of some molecules, such as angiogenic factors, could improve repair and recovery in many tissue types. This article uses a comprehensive approach to examine data obtained in recent years. We consider evidence collected from different tissues, including myocardial capillarization, skeletal muscle fiber types and fiber size changes induced by intermittent hypoxia exposure, and discuss the evidence that points to beneficial interventions in applied fields such as sport science. Short-term intermittent hypoxia may not only be useful for healthy people, but could also be considered a promising tool to be applied, with due caution, to some pathophysiological states.
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Affiliation(s)
- Ginés Viscor
- Physiology Section, Department of Cell Biology, Physiology and Immunology, Faculty of Biology, Universitat de Barcelona, Barcelona, Spain
| | - Joan R. Torrella
- Physiology Section, Department of Cell Biology, Physiology and Immunology, Faculty of Biology, Universitat de Barcelona, Barcelona, Spain
| | - Luisa Corral
- Exercise Physiology Unit, Department of Physiological Sciences, Faculty of Medicine and Health Sciences, Universitat de Barcelona, L'Hospitalet de Llobregat, Barcelona, Spain
| | - Antoni Ricart
- Exercise Physiology Unit, Department of Physiological Sciences, Faculty of Medicine and Health Sciences, Universitat de Barcelona, L'Hospitalet de Llobregat, Barcelona, Spain
| | - Casimiro Javierre
- Exercise Physiology Unit, Department of Physiological Sciences, Faculty of Medicine and Health Sciences, Universitat de Barcelona, L'Hospitalet de Llobregat, Barcelona, Spain
| | - Teresa Pages
- Physiology Section, Department of Cell Biology, Physiology and Immunology, Faculty of Biology, Universitat de Barcelona, Barcelona, Spain
| | - Josep L. Ventura
- Exercise Physiology Unit, Department of Physiological Sciences, Faculty of Medicine and Health Sciences, Universitat de Barcelona, L'Hospitalet de Llobregat, Barcelona, Spain
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47
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Dawson NJ, Lyons SA, Henry DA, Scott GR. Effects of chronic hypoxia on diaphragm function in deer mice native to high altitude. Acta Physiol (Oxf) 2018; 223:e13030. [PMID: 29316265 DOI: 10.1111/apha.13030] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Revised: 12/08/2017] [Accepted: 12/31/2017] [Indexed: 12/22/2022]
Abstract
AIM We examined the effects of chronic hypoxia on diaphragm function in high- and low-altitude populations of Peromyscus mice. METHODS Deer mice (P. maniculatus) native to high altitude and congeneric mice native to low altitude (P. leucopus) were born and raised in captivity to adulthood and were acclimated to normoxia or hypobaric hypoxia (12 or 9 kPa, simulating hypoxia at 4300 and 7000 m) for 6-8 weeks. We then measured indices of mitochondrial respiration capacity, force production, and fatigue resistance in the diaphragm. RESULTS Mitochondrial respiratory capacities (assessed using permeabilized fibres with single or multiple inputs to the electron transport system), citrate synthase activity (a marker of mitochondrial volume), twitch force production, and muscle fatigue resistance increased after exposure to chronic hypoxia in both populations. These changes were not well explained by variation in the fibre-type composition of the muscle. However, there were several differences in diaphragm function in high-altitude mice compared to low-altitude mice. Exposure to a deeper level of hypoxia (9 kPa vs 12 kPa) was needed to elicit increases in mitochondrial respiration rates in highlanders. Chronic hypoxia did not increase the emission of reactive oxygen species from permeabilized fibres in highlanders, in contrast to the pronounced increases that occurred in lowlanders. In general, the diaphragm of high-altitude mice had greater capillary length densities, produced less force in response to stimulation and had shorter relaxation times. The latter was associated with higher activity of sarcoplasmic reticulum Ca2+ -ATPase (SERCA) activity in the diaphragm of high-altitude mice. CONCLUSION Overall, our work suggests that exposure to chronic hypoxia increases the capacities for mitochondrial respiration, force production and fatigue resistance of the diaphragm. However, many of these effects are opposed by evolved changes in diaphragm function in high-altitude natives, such that highlanders in chronic hypoxia maintain similar diaphragm function to lowlanders in sea level conditions.
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Affiliation(s)
- N. J. Dawson
- Department of Biology; McMaster University; Hamilton ON Canada
| | - S. A. Lyons
- Department of Biology; McMaster University; Hamilton ON Canada
| | - D. A. Henry
- Department of Biology; McMaster University; Hamilton ON Canada
| | - G. R. Scott
- Department of Biology; McMaster University; Hamilton ON Canada
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48
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Metabolic adjustment to high-altitude hypoxia: from genetic signals to physiological implications. Biochem Soc Trans 2018; 46:599-607. [PMID: 29678953 DOI: 10.1042/bst20170502] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Revised: 03/24/2018] [Accepted: 03/27/2018] [Indexed: 01/04/2023]
Abstract
Ascent to high altitude is associated with physiological responses that counter the stress of hypobaric hypoxia by increasing oxygen delivery and by altering tissue oxygen utilisation via metabolic modulation. At the cellular level, the transcriptional response to hypoxia is mediated by the hypoxia-inducible factor (HIF) pathway and results in promotion of glycolytic capacity and suppression of oxidative metabolism. In Tibetan highlanders, gene variants encoding components of the HIF pathway have undergone selection and are associated with adaptive phenotypic changes, including suppression of erythropoiesis and increased blood lactate levels. In some highland populations, there has also been a selection of variants in PPARA, encoding peroxisome proliferator-activated receptor alpha (PPARα), a transcriptional regulator of fatty acid metabolism. In one such population, the Sherpas, lower muscle PPARA expression is associated with a decreased capacity for fatty acid oxidation, potentially improving the efficiency of oxygen utilisation. In lowlanders ascending to altitude, a similar suppression of fatty acid oxidation occurs, although the underlying molecular mechanism appears to differ along with the consequences. Unlike lowlanders, Sherpas appear to be protected against oxidative stress and the accumulation of intramuscular lipid intermediates at altitude. Moreover, Sherpas are able to defend muscle ATP and phosphocreatine levels in the face of decreased oxygen delivery, possibly due to suppression of ATP demand pathways. The molecular mechanisms allowing Sherpas to successfully live, work and reproduce at altitude may hold the key to novel therapeutic strategies for the treatment of diseases to which hypoxia is a fundamental contributor.
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49
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Chicco AJ, Le CH, Gnaiger E, Dreyer HC, Muyskens JB, D'Alessandro A, Nemkov T, Hocker AD, Prenni JE, Wolfe LM, Sindt NM, Lovering AT, Subudhi AW, Roach RC. Adaptive remodeling of skeletal muscle energy metabolism in high-altitude hypoxia: Lessons from AltitudeOmics. J Biol Chem 2018. [PMID: 29540485 DOI: 10.1074/jbc.ra117.000470] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Metabolic responses to hypoxia play important roles in cell survival strategies and disease pathogenesis in humans. However, the homeostatic adjustments that balance changes in energy supply and demand to maintain organismal function under chronic low oxygen conditions remain incompletely understood, making it difficult to distinguish adaptive from maladaptive responses in hypoxia-related pathologies. We integrated metabolomic and proteomic profiling with mitochondrial respirometry and blood gas analyses to comprehensively define the physiological responses of skeletal muscle energy metabolism to 16 days of high-altitude hypoxia (5260 m) in healthy volunteers from the AltitudeOmics project. In contrast to the view that hypoxia down-regulates aerobic metabolism, results show that mitochondria play a central role in muscle hypoxia adaptation by supporting higher resting phosphorylation potential and enhancing the efficiency of long-chain acylcarnitine oxidation. This directs increases in muscle glucose toward pentose phosphate and one-carbon metabolism pathways that support cytosolic redox balance and help mitigate the effects of increased protein and purine nucleotide catabolism in hypoxia. Muscle accumulation of free amino acids favor these adjustments by coordinating cytosolic and mitochondrial pathways to rid the cell of excess nitrogen, but might ultimately limit muscle oxidative capacity in vivo Collectively, these studies illustrate how an integration of aerobic and anaerobic metabolism is required for physiological hypoxia adaptation in skeletal muscle, and highlight protein catabolism and allosteric regulation as unexpected orchestrators of metabolic remodeling in this context. These findings have important implications for the management of hypoxia-related diseases and other conditions associated with chronic catabolic stress.
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Affiliation(s)
- Adam J Chicco
- From the Departments of Biomedical Sciences, .,Cell and Molecular Biology, and
| | | | - Erich Gnaiger
- the Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - Hans C Dreyer
- the Department of Human Physiology, University of Oregon, Eugene, Oregon 97403-1240, and
| | - Jonathan B Muyskens
- the Department of Human Physiology, University of Oregon, Eugene, Oregon 97403-1240, and
| | | | - Travis Nemkov
- the Department of Biochemistry and Molecular Genetics and
| | - Austin D Hocker
- the Department of Human Physiology, University of Oregon, Eugene, Oregon 97403-1240, and
| | - Jessica E Prenni
- Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado 80523
| | - Lisa M Wolfe
- Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado 80523
| | - Nathan M Sindt
- Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado 80523
| | - Andrew T Lovering
- the Department of Human Physiology, University of Oregon, Eugene, Oregon 97403-1240, and
| | - Andrew W Subudhi
- the Department of Biology, University of Colorado, Colorado Springs, Colorado 80918
| | - Robert C Roach
- Altitude Research Center, University of Colorado-Anschutz Medical Campus, Aurora 80045, Colorado 80045
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50
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Li Y, Liu Z, Zhang Y, Zhao Q, Wang X, Lu P, Zhang H, Wang Z, Dong H, Zhang Z. PEDF protects cardiomyocytes by promoting FUNDC1‑mediated mitophagy via PEDF-R under hypoxic condition. Int J Mol Med 2018; 41:3394-3404. [PMID: 29512692 PMCID: PMC5881750 DOI: 10.3892/ijmm.2018.3536] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2016] [Accepted: 02/15/2018] [Indexed: 01/15/2023] Open
Abstract
Pigment epithelial-derived factor (PEDF) is known to exert diverse physiological activities. Previous studies suggest that hypoxia could induce mitophagy. Astoundingly, under hypoxic condition, we found that PEDF decreased the mitochondrial density of cardiomyocytes. In this study, we evaluated whether PEDF could decrease the mitochondrial density and play a protective role in hypoxic cardiomyocytes via promoting mitophagy. Immunostaining and western blotting were used to analyze mitochondrial density and mitophagy of hypoxic cardiomyocytes. Gas chromatography-mass spectrometry and ELISA were used to analyze levels of palmitic acid and diacylglycerol. Transmission Electron Microscopy was used to detect mitophagy and the mitochondrial density in adult male Sprague-Dawley rat model of acute myocardial infarction. Compared to the control group, we observed that PEDF decreased mitochondrial density through promoting hypoxic cardiomyocyte mitophagy. PEDF increased the levels of palmitic acid and diacylglycerol, and then upregulated the levels of protein kinase Cα (PKC-α) and its activation. Furthermore, inhibition of PKC-α by Go6976 could effectively suppress PEDF-induced mitophagy. Besides, we found that PEDF promoted FUNDC1-mediated cardiomyocyte mitophagy via ULK1, which depended on the activation of PKC-α. Finally, we discovered that mitophagy was increased and mitochondrial density was reduced in adult male Sprague-Dawley rat model of acute myocardial infarction. We concluded that PEDF promotes mitophagy to protect hypoxic cardiomyocytes, through PEDF/PEDF-R/PA/DAG/PKC-α/ULK1/FUNDC1 pathway.
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Affiliation(s)
- Yufeng Li
- Department of Thoracic Cardiovascular Surgery, Affiliated Hospital of Xuzhou Medical University, Xuzhou, Jiangsu 221006, P.R. China
| | - Zhiwei Liu
- Research Facility Center for Morphology, Xuzhou Medical University, Xuzhou, Jiangsu 221004, P.R. China
| | - Yiqian Zhang
- Department of Thoracic Cardiovascular Surgery, Affiliated Hospital of Xuzhou Medical University, Xuzhou, Jiangsu 221006, P.R. China
| | - Qixiang Zhao
- Department of Thoracic Cardiovascular Surgery, Affiliated Hospital of Xuzhou Medical University, Xuzhou, Jiangsu 221006, P.R. China
| | - Xiaoyu Wang
- Department of Thoracic Cardiovascular Surgery, Affiliated Hospital of Xuzhou Medical University, Xuzhou, Jiangsu 221006, P.R. China
| | - Peng Lu
- Department of Thoracic Cardiovascular Surgery, Affiliated Hospital of Xuzhou Medical University, Xuzhou, Jiangsu 221006, P.R. China
| | - Hao Zhang
- Department of Thoracic Cardiovascular Surgery, Affiliated Hospital of Xuzhou Medical University, Xuzhou, Jiangsu 221006, P.R. China
| | - Zhu Wang
- Department of Thoracic Cardiovascular Surgery, Affiliated Hospital of Xuzhou Medical University, Xuzhou, Jiangsu 221006, P.R. China
| | - Hongyan Dong
- Research Facility Center for Morphology, Xuzhou Medical University, Xuzhou, Jiangsu 221004, P.R. China
| | - Zhongming Zhang
- Department of Thoracic Cardiovascular Surgery, Affiliated Hospital of Xuzhou Medical University, Xuzhou, Jiangsu 221006, P.R. China
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