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Raberin A, Burtscher J, Burtscher M, Millet GP. Hypoxia and the Aging Cardiovascular System. Aging Dis 2023; 14:2051-2070. [PMID: 37199587 PMCID: PMC10676797 DOI: 10.14336/ad.2023.0424] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Accepted: 04/24/2023] [Indexed: 05/19/2023] Open
Abstract
Older individuals represent a growing population, in industrialized countries, particularly those with cardiovascular diseases, which remain the leading cause of death in western societies. Aging constitutes one of the largest risks for cardiovascular diseases. On the other hand, oxygen consumption is the foundation of cardiorespiratory fitness, which in turn is linearly related to mortality, quality of life and numerous morbidities. Therefore, hypoxia is a stressor that induces beneficial or harmful adaptations, depending on the dose. While severe hypoxia can exert detrimental effects, such as high-altitude illnesses, moderate and controlled oxygen exposure can potentially be used therapeutically. It can improve numerous pathological conditions, including vascular abnormalities, and potentially slows down the progression of various age-related disorders. Hypoxia can exert beneficial effects on inflammation, oxidative stress, mitochondrial functions, and cell survival, which are all increased with age and have been discussed as main promotors of aging. This narrative review discusses specificities of the aging cardiovascular system in hypoxia. It draws upon an extensive literature search on the effects of hypoxia/altitude interventions (acute, prolonged, or intermittent exposure) on the cardiovascular system in older individuals (over 50 years old). Special attention is directed toward the use of hypoxia exposure to improve cardiovascular health in older individuals.
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Affiliation(s)
- Antoine Raberin
- Institute of Sport Sciences, University of Lausanne, CH-1015, Lausanne, Switzerland.
| | - Johannes Burtscher
- Institute of Sport Sciences, University of Lausanne, CH-1015, Lausanne, Switzerland.
| | - Martin Burtscher
- Department of Sport Science, University of Innsbruck, Innsbruck, A-6020, Austria.
| | - Grégoire P. Millet
- Institute of Sport Sciences, University of Lausanne, CH-1015, Lausanne, Switzerland.
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Burtscher J, Citherlet T, Camacho-Cardenosa A, Camacho-Cardenosa M, Raberin A, Krumm B, Hohenauer E, Egg M, Lichtblau M, Müller J, Rybnikova EA, Gatterer H, Debevec T, Baillieul S, Manferdelli G, Behrendt T, Schega L, Ehrenreich H, Millet GP, Gassmann M, Schwarzer C, Glazachev O, Girard O, Lalande S, Hamlin M, Samaja M, Hüfner K, Burtscher M, Panza G, Mallet RT. Mechanisms underlying the health benefits of intermittent hypoxia conditioning. J Physiol 2023. [PMID: 37860950 DOI: 10.1113/jp285230] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2023] [Accepted: 10/11/2023] [Indexed: 10/21/2023] Open
Abstract
Intermittent hypoxia (IH) is commonly associated with pathological conditions, particularly obstructive sleep apnoea. However, IH is also increasingly used to enhance health and performance and is emerging as a potent non-pharmacological intervention against numerous diseases. Whether IH is detrimental or beneficial for health is largely determined by the intensity, duration, number and frequency of the hypoxic exposures and by the specific responses they engender. Adaptive responses to hypoxia protect from future hypoxic or ischaemic insults, improve cellular resilience and functions, and boost mental and physical performance. The cellular and systemic mechanisms producing these benefits are highly complex, and the failure of different components can shift long-term adaptation to maladaptation and the development of pathologies. Rather than discussing in detail the well-characterized individual responses and adaptations to IH, we here aim to summarize and integrate hypoxia-activated mechanisms into a holistic picture of the body's adaptive responses to hypoxia and specifically IH, and demonstrate how these mechanisms might be mobilized for their health benefits while minimizing the risks of hypoxia exposure.
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Affiliation(s)
- Johannes Burtscher
- Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland
| | - Tom Citherlet
- Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland
| | - Alba Camacho-Cardenosa
- Department of Physical Education and Sports, Faculty of Sports Science, Sport and Health University Research Institute (iMUDS), University of Granada, Granada, Spain
| | - Marta Camacho-Cardenosa
- Clinical Management Unit of Endocrinology and Nutrition - GC17, Maimónides Biomedical Research Institute of Cordoba (IMIBIC), Reina Sofía University Hospital, Córdoba, Spain
| | - Antoine Raberin
- Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland
| | - Bastien Krumm
- Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland
| | - Erich Hohenauer
- Rehabilitation and Exercise Science Laboratory (RES lab), Department of Business Economics, Health and Social Care, University of Applied Sciences and Arts of Southern Switzerland, Landquart, Switzerland
- International University of Applied Sciences THIM, Landquart, Switzerland
- Department of Neurosciences and Movement Science, University of Fribourg, Fribourg, Switzerland
| | - Margit Egg
- Institute of Zoology, University of Innsbruck, Innsbruck, Austria
| | - Mona Lichtblau
- Department of Pulmonology, University Hospital Zurich, Zurich, Switzerland
- University of Zurich, Zurich, Switzerland
| | - Julian Müller
- Department of Pulmonology, University Hospital Zurich, Zurich, Switzerland
- University of Zurich, Zurich, Switzerland
| | - Elena A Rybnikova
- Pavlov Institute of Physiology, Russian Academy of Sciences, St Petersburg, Russia
| | - Hannes Gatterer
- Institute of Mountain Emergency Medicine, Eurac Research, Bolzano, Italy
- Institute for Sports Medicine, Alpine Medicine and Health Tourism (ISAG), UMIT TIROL-Private University for Health Sciences and Health Technology, Hall in Tirol, Austria
| | - Tadej Debevec
- Faculty of Sport, University of Ljubljana, Ljubljana, Slovenia
- Department of Automatics, Biocybernetics and Robotics, Jožef Stefan Institute, Ljubljana, Slovenia
| | - Sebastien Baillieul
- Service Universitaire de Pneumologie Physiologie, University of Grenoble Alpes, Inserm, Grenoble, France
| | | | - Tom Behrendt
- Chair Health and Physical Activity, Department of Sport Science, Institute III, Otto von Guericke University Magdeburg, Magdeburg, Germany
| | - Lutz Schega
- Chair Health and Physical Activity, Department of Sport Science, Institute III, Otto von Guericke University Magdeburg, Magdeburg, Germany
| | - Hannelore Ehrenreich
- Clinical Neuroscience, University Medical Center and Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Grégoire P Millet
- Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland
| | - Max Gassmann
- Institute of Veterinary Physiology, Vetsuisse Faculty, University of Zürich, Zurich, Switzerland
- Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland
- Universidad Peruana Cayetano Heredia (UPCH), Lima, Peru
| | - Christoph Schwarzer
- Institute of Pharmacology, Medical University of Innsbruck, Innsbruck, Austria
| | - Oleg Glazachev
- Department of Normal Physiology, N.V. Sklifosovsky Institute of Clinical Medicine, I. M. Sechenov First Moscow State Medical University, Moscow, Russia
| | - Olivier Girard
- School of Human Sciences (Exercise and Sport Science), The University of Western Australia, Crawley, Western Australia, Australia
| | - Sophie Lalande
- Department of Kinesiology and Health Education, University of Texas at Austin, Austin, TX, USA
| | - Michael Hamlin
- Department of Tourism, Sport and Society, Lincoln University, Christchurch, New Zealand
| | - Michele Samaja
- Department of Health Science, University of Milan, Milan, Italy
| | - Katharina Hüfner
- Department of Psychiatry, Psychotherapy, Psychosomatics and Medical Psychology, University Hospital for Psychiatry II, Medical University of Innsbruck, Innsbruck, Austria
| | - Martin Burtscher
- Department of Sport Science, University of Innsbruck, Innsbruck, Austria
| | - Gino Panza
- The Department of Health Care Sciences, Program of Occupational Therapy, Wayne State University, Detroit, MI, USA
- John D. Dingell VA Medical Center Detroit, Detroit, MI, USA
| | - Robert T Mallet
- Department of Physiology & Anatomy, University of North Texas Health Science Center, Fort Worth, TX, USA
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Bestavashvili A, Glazachev O, Ibragimova S, Suvorov A, Bestavasvili A, Ibraimov S, Zhang X, Zhang Y, Pavlov C, Syrkina E, Syrkin A, Kopylov P. Impact of Hypoxia-Hyperoxia Exposures on Cardiometabolic Risk Factors and TMAO Levels in Patients with Metabolic Syndrome. Int J Mol Sci 2023; 24:14498. [PMID: 37833946 PMCID: PMC10572339 DOI: 10.3390/ijms241914498] [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: 07/04/2023] [Revised: 09/11/2023] [Accepted: 09/18/2023] [Indexed: 10/15/2023] Open
Abstract
Along with the known risk factors of cardiovascular diseases (CVDs) constituting metabolic syndrome (MS), the gut microbiome and some of its metabolites, in particular trimethylamine-N-oxide (TMAO), are actively discussed. A prolonged stay under natural hypoxic conditions significantly and multi-directionally changes the ratio of gut microbiome strains and their metabolites in feces and blood, which is the basis for using hypoxia preconditioning for targeted effects on potential risk factors of CVD. A prospective randomized study included 65 patients (32 females) with MS and optimal medical therapy. Thirty-three patients underwent a course of 15 intermittent hypoxic-hyperoxic exposures (IHHE group). The other 32 patients underwent sham procedures (placebo group). Before and after the IHHE course, patients underwent liver elastometry, biochemical blood tests, and blood and fecal sampling for TMAO analysis (tandem mass spectrometry). No significant dynamics of TMAO were detected in both the IHHE and sham groups. In the subgroup of IHHE patients with baseline TMAO values above the reference (TMAO ≥ 5 μmol/l), there was a significant reduction in TMAO plasma levels. But the degree of reduction in total cholesterol (TCh), low-density lipoprotein (LDL), and regression of liver steatosis index was more pronounced in patients with initially normal TMAO values. Despite significant interindividual variations, in the subgroup of IHHE patients with MS and high baseline TMAO values, there were more significant reductions in cardiometabolic and hepatic indicators of MS than in controls. More research is needed to objectify the prognostic role of TMAO and the possibilities of its correction using hypoxia adaptation techniques.
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Affiliation(s)
- Afina Bestavashvili
- World-Class Research Center "Digital Biodesign and Personalized Healthcare", I. M. Sechenov First Moscow State Medical University, 119991 Moscow, Russia
| | - Oleg Glazachev
- Department of Normal Physiology, N.V. Sklifosovsky Institute of Clinical Medicine, I. M. Sechenov First Moscow State Medical University, 119991 Moscow, Russia
| | - Shabnam Ibragimova
- Department of Therapy of the Institute of Professional Education, I. M. Sechenov First Moscow State Medical University, 119991 Moscow, Russia
| | - Alexander Suvorov
- World-Class Research Center "Digital Biodesign and Personalized Healthcare", I. M. Sechenov First Moscow State Medical University, 119991 Moscow, Russia
| | | | - Shevket Ibraimov
- Department of Cardiology, Functional and Ultrasound Diagnostics, N.V. Sklifosovsky Institute of Clinical Medicine, I. M. Sechenov First Moscow State Medical University, 119991 Moscow, Russia
| | - Xinliang Zhang
- Department of Normal Physiology, N.V. Sklifosovsky Institute of Clinical Medicine, I. M. Sechenov First Moscow State Medical University, 119991 Moscow, Russia
| | - Yong Zhang
- The State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Research, Ministry of Education, Department of Pharmacology, Harbin Medical University, Harbin 150081, China
| | - Chavdar Pavlov
- Department of Therapy of the Institute of Professional Education, I. M. Sechenov First Moscow State Medical University, 119991 Moscow, Russia
- Department of Gastroenterology, Botkin Hospital, 125284 Moscow, Russia
| | - Elena Syrkina
- Department of Cardiology, Functional and Ultrasound Diagnostics, N.V. Sklifosovsky Institute of Clinical Medicine, I. M. Sechenov First Moscow State Medical University, 119991 Moscow, Russia
| | - Abram Syrkin
- Department of Cardiology, Functional and Ultrasound Diagnostics, N.V. Sklifosovsky Institute of Clinical Medicine, I. M. Sechenov First Moscow State Medical University, 119991 Moscow, Russia
| | - Philipp Kopylov
- World-Class Research Center "Digital Biodesign and Personalized Healthcare", I. M. Sechenov First Moscow State Medical University, 119991 Moscow, Russia
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Burtscher J, Hohenauer E, Burtscher M, Millet GP, Egg M. Environmental and behavioral regulation of HIF-mitochondria crosstalk. Free Radic Biol Med 2023; 206:63-73. [PMID: 37385566 DOI: 10.1016/j.freeradbiomed.2023.06.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Revised: 06/05/2023] [Accepted: 06/19/2023] [Indexed: 07/01/2023]
Abstract
Reduced oxygen availability (hypoxia) can lead to cell and organ damage. Therefore, aerobic species depend on efficient mechanisms to counteract detrimental consequences of hypoxia. Hypoxia inducible factors (HIFs) and mitochondria are integral components of the cellular response to hypoxia and coordinate both distinct and highly intertwined adaptations. This leads to reduced dependence on oxygen, improved oxygen supply, maintained energy provision by metabolic remodeling and tapping into alternative pathways and increased resilience to hypoxic injuries. On one hand, many pathologies are associated with hypoxia and hypoxia can drive disease progression, for example in many cancer and neurological diseases. But on the other hand, controlled induction of hypoxia responses via HIFs and mitochondria can elicit profound health benefits and increase resilience. To tackle pathological hypoxia conditions or to apply health-promoting hypoxia exposures efficiently, cellular and systemic responses to hypoxia need to be well understood. Here we first summarize the well-established link between HIFs and mitochondria in orchestrating hypoxia-induced adaptations and then outline major environmental and behavioral modulators of their interaction that remain poorly understood.
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Affiliation(s)
- Johannes Burtscher
- Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland.
| | - Erich Hohenauer
- Rehabilitation and Exercise Science Laboratory (RES Lab), Department of Business Economics, Health and Social Care, University of Applied Sciences and Arts of Southern Switzerland, Landquart, Switzerland; International University of Applied Sciences THIM, Landquart, Switzerland; Department of Neurosciences and Movement Science, University of Fribourg, Fribourg, Switzerland; Department of Movement and Sport Sciences, Vrije Universiteit Brussel, Brussels, Belgium
| | - Martin Burtscher
- Department of Sport Science, University of Innsbruck, Innsbruck, Austria
| | - Grégoire P Millet
- Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland
| | - Margit Egg
- Institute of Zoology, University of Innsbruck, Innsbruck, Austria
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Yang Y, Gao C, Yang T, Sha Y, Cai Y, Wang X, Yang Q, Liu C, Wang B, Zhao S. Vascular characteristics and expression of hypoxia genes in Tibetan pigs' hearts. Vet Med Sci 2021; 8:177-186. [PMID: 34561963 PMCID: PMC8788992 DOI: 10.1002/vms3.639] [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] [Indexed: 12/23/2022] Open
Abstract
Background Tibetan pigs have exhibited unique characteristics from low‐altitudes pigs and adapted well to the Qinghai‐Tibet Plateau. Objectives The current study was undertaken to investigate the hypoxic adaptation of heart in Tibetan pigs. Methods The hearts of Tibetan pigs and Landrace pigs raised at high or low altitudes were compared using 3D casting technology, scanning electron microscopy and real‐time quantitative PCR (qRT‐PCR). Results We found that the ratio of the major axis to the minor axis and the density of the heart were significantly higher in Tibetan pigs than in Landrace pigs (p < 0.05). Tibetan pigs had larger diameters and higher densities of arterioles than Landrace pigs (p < 0.05), and these features have a similar variation with the expression of vascular endothelial growth factor (VEGF). The cardiac expression levels of hypoxia‐inducible factor‐1α (HIF‐1α) and endothelial nitric oxide synthase (eNOS) were significantly higher in pigs reared at high altitudes than in those reared at low altitudes (p < 0.05). In contrast, Egl nine homolog 1 (EGLN1) had the opposite trend with respect to HIF‐1α and eNOS and was related to red blood cell (RBC) counts. Notably, the expressions of erythropoietin (EPO) and endothelial PAS domain‐containing protein 1 (EPAS1) were significantly higher in Landrace pigs kept at high altitudes than in the others (p < 0.05) and were associated with haemoglobin. Conclusions These findings show that the regulation of the heart function of Tibetan pigs in a hypoxic environment is manifested at various levels to ensure the circulation of blood under extreme environmental conditions.
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Affiliation(s)
- Yanan Yang
- College of Animal Science & Technology, Gansu Agricultural University, Lanzhou, P.R. China
| | - Caixia Gao
- State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, P.R. China
| | - Tianliang Yang
- College of Animal Science & Technology, Gansu Agricultural University, Lanzhou, P.R. China
| | - Yuzhu Sha
- College of Animal Science & Technology, Gansu Agricultural University, Lanzhou, P.R. China
| | - Yuan Cai
- College of Animal Science & Technology, Gansu Agricultural University, Lanzhou, P.R. China
| | - Xinrong Wang
- College of Animal Science & Technology, Gansu Agricultural University, Lanzhou, P.R. China
| | - Qiaoli Yang
- College of Animal Science & Technology, Gansu Agricultural University, Lanzhou, P.R. China
| | - Chengze Liu
- College of Animal Science & Technology, Gansu Agricultural University, Lanzhou, P.R. China
| | - Biao Wang
- College of Animal Science & Technology, Gansu Agricultural University, Lanzhou, P.R. China
| | - Shengguo Zhao
- College of Animal Science & Technology, Gansu Agricultural University, Lanzhou, P.R. China
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Burtscher J, Syed MMK, Keller MA, Lashuel HA, Millet GP. Fatal attraction - The role of hypoxia when alpha-synuclein gets intimate with mitochondria. Neurobiol Aging 2021; 107:128-141. [PMID: 34428721 DOI: 10.1016/j.neurobiolaging.2021.07.017] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 07/21/2021] [Accepted: 07/24/2021] [Indexed: 12/21/2022]
Abstract
Alpha-synuclein aggregation and mitochondrial dysfunction are main pathological hallmarks of Parkinson's disease (PD) and several other neurodegenerative diseases, collectively known as synucleinopathies. However, increasing evidence suggests that they may not be sufficient to cause PD. Here we propose the role of hypoxia as a missing link that connects the complex interplay between alpha-synuclein biochemistry and pathology, mitochondrial dysfunctions and neurodegeneration in PD. We review the partly conflicting literature on alpha-synuclein binding to membranes and mitochondria and its impact on mitochondrial functions. From there, we focus on adverse changes in cellular environments, revolving around hypoxic stress, that may trigger or facilitate PD progression. Inter-dependent structural re-arrangements of mitochondrial membranes, including increased cytoplasmic exposure of mitochondrial cardiolipins and changes in alpha-synuclein localization and conformation are discussed consequences of such conditions. Enhancing cellular resilience could be an integral part of future combination-based therapies of PD. This may be achieved by boosting the capacity of cellular and specifically mitochondrial processes to regulate and adapt to altered proteostasis, redox, and inflammatory conditions and by inducing protective molecular and tissue re-modelling.
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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.
| | - Muhammed Muazzam Kamil Syed
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, Brain Mind Institute, EPFL, Lausanne, Switzerland
| | - Markus A Keller
- Institute of Human Genetics, Medical University of Innsbruck, Innsbruck, Austria
| | - Hilal A Lashuel
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, Brain Mind Institute, EPFL, Lausanne, Switzerland
| | - Grégoire P Millet
- Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland
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Burtscher J, Mallet RT, Burtscher M, Millet GP. Hypoxia and brain aging: Neurodegeneration or neuroprotection? Ageing Res Rev 2021; 68:101343. [PMID: 33862277 DOI: 10.1016/j.arr.2021.101343] [Citation(s) in RCA: 100] [Impact Index Per Article: 33.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 04/06/2021] [Accepted: 04/09/2021] [Indexed: 12/12/2022]
Abstract
The absolute reliance of the mammalian brain on oxygen to generate ATP renders it acutely vulnerable to hypoxia, whether at high altitude or in clinical settings of anemia or pulmonary disease. Hypoxia is pivotal to the pathogeneses of myriad neurological disorders, including Alzheimer's, Parkinson's and other age-related neurodegenerative diseases. Conversely, reduced environmental oxygen, e.g. sojourns or residing at high altitudes, may impart favorable effects on aging and mortality. Moreover, controlled hypoxia exposure may represent a treatment strategy for age-related neurological disorders. This review discusses evidence of hypoxia's beneficial vs. detrimental impacts on the aging brain and the molecular mechanisms that mediate these divergent effects. It draws upon an extensive literature search on the effects of hypoxia/altitude on brain aging, and detailed analysis of all identified studies directly comparing brain responses to hypoxia in young vs. aged humans or rodents. Special attention is directed toward the risks vs. benefits of hypoxia exposure to the elderly, and potential therapeutic applications of hypoxia for neurodegenerative diseases. Finally, important questions for future research are discussed.
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Affiliation(s)
- Johannes Burtscher
- Department of Biomedical Sciences, University of Lausanne, CH-1015, Lausanne, Switzerland; Institute of Sport Sciences, University of Lausanne, CH-1015, Lausanne, Switzerland.
| | - Robert T Mallet
- Department of Physiology and Anatomy, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | - Martin Burtscher
- Department of Sport Science, University of Innsbruck, Innsbruck, Austria
| | - Grégoire P Millet
- Institute of Sport Sciences, University of Lausanne, CH-1015, Lausanne, Switzerland
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8
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Mallet RT, Burtscher J, Richalet JP, Millet GP, Burtscher M. Impact of High Altitude on Cardiovascular Health: Current Perspectives. Vasc Health Risk Manag 2021; 17:317-335. [PMID: 34135590 PMCID: PMC8197622 DOI: 10.2147/vhrm.s294121] [Citation(s) in RCA: 52] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 05/12/2021] [Indexed: 12/12/2022] Open
Abstract
Globally, about 400 million people reside at terrestrial altitudes above 1500 m, and more than 100 million lowlanders visit mountainous areas above 2500 m annually. The interactions between the low barometric pressure and partial pressure of O2, climate, individual genetic, lifestyle and socio-economic factors, as well as adaptation and acclimatization processes at high elevations are extremely complex. It is challenging to decipher the effects of these myriad factors on the cardiovascular health in high altitude residents, and even more so in those ascending to high altitudes with or without preexisting diseases. This review aims to interpret epidemiological observations in high-altitude populations; present and discuss cardiovascular responses to acute and subacute high-altitude exposure in general and more specifically in people with preexisting cardiovascular diseases; the relations between cardiovascular pathologies and neurodegenerative diseases at altitude; the effects of high-altitude exercise; and the putative cardioprotective mechanisms of hypobaric hypoxia.
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Affiliation(s)
- Robert T Mallet
- Department of Physiology and Anatomy, University of North Texas Health Science Center, Fort Worth, TX, USA
| | - Johannes Burtscher
- Department of Biomedical Sciences, University of Lausanne, Lausanne, CH-1015, Switzerland
- Institute of Sport Sciences, University of Lausanne, Lausanne, CH-1015, Switzerland
| | - Jean-Paul Richalet
- Laboratoire Hypoxie & Poumon, UMR Inserm U1272, Université Sorbonne Paris Nord 13, Bobigny Cedex, F-93017, France
| | - Gregoire P Millet
- Department of Biomedical Sciences, University of Lausanne, Lausanne, CH-1015, Switzerland
- Institute of Sport Sciences, University of Lausanne, Lausanne, CH-1015, Switzerland
| | - Martin Burtscher
- Department of Sport Science, University of Innsbruck, Innsbruck, A-6020, Austria
- Austrian Society for Alpine and High-Altitude Medicine, Mieming, Austria
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9
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A Rationale for Hypoxic and Chemical Conditioning in Huntington's Disease. Int J Mol Sci 2021; 22:ijms22020582. [PMID: 33430140 PMCID: PMC7826574 DOI: 10.3390/ijms22020582] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 12/23/2020] [Accepted: 01/05/2021] [Indexed: 12/17/2022] Open
Abstract
Neurodegenerative diseases are characterized by adverse cellular environments and pathological alterations causing neurodegeneration in distinct brain regions. This development is triggered or facilitated by conditions such as hypoxia, ischemia or inflammation and is associated with disruptions of fundamental cellular functions, including metabolic and ion homeostasis. Targeting intracellular downstream consequences to specifically reverse these pathological changes proved difficult to translate to clinical settings. Here, we discuss the potential of more holistic approaches with the purpose to re-establish a healthy cellular environment and to promote cellular resilience. We review the involvement of important molecular pathways (e.g., the sphingosine, δ-opioid receptor or N-Methyl-D-aspartate (NMDA) receptor pathways) in neuroprotective hypoxic conditioning effects and how these pathways can be targeted for chemical conditioning. Despite the present scarcity of knowledge on the efficacy of such approaches in neurodegeneration, the specific characteristics of Huntington’s disease may make it particularly amenable for such conditioning techniques. Not only do classical features of neurodegenerative diseases like mitochondrial dysfunction, oxidative stress and inflammation support this assumption, but also specific Huntington’s disease characteristics: a relatively young age of neurodegeneration, molecular overlap of related pathologies with hypoxic adaptations and sensitivity to brain hypoxia. The aim of this review is to discuss several molecular pathways in relation to hypoxic adaptations that have potential as drug targets in neurodegenerative diseases. We will extract the relevance for Huntington’s disease from this knowledge base.
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10
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Millet GP, Debevec T, Brocherie F, Burtscher M, Burtscher J. Altitude and COVID-19: Friend or foe? A narrative review. Physiol Rep 2021; 8:e14615. [PMID: 33340275 PMCID: PMC7749581 DOI: 10.14814/phy2.14615] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Revised: 09/22/2020] [Accepted: 09/23/2020] [Indexed: 12/11/2022] Open
Abstract
Recent reports suggest that high-altitude residence may be beneficial in the novel coronavirus disease (COVID-19) implicating that traveling to high places or using hypoxic conditioning thus could be favorable as well. Physiological high-altitude characteristics and symptoms of altitude illnesses furthermore seem similar to several pathologies associated with COVID-19. As a consequence, high altitude and hypoxia research and related clinical practices are discussed for potential applications in COVID-19 prevention and treatment. We summarize the currently available evidence on the relationship between altitude/hypoxia conditions and COVID-19 epidemiology and pathophysiology. The potential for treatment strategies used for altitude illnesses is evaluated. Symptomatic overlaps in the pathophysiology of COVID-19 induced ARDS and high altitude illnesses (i.e., hypoxemia, dyspnea…) have been reported but are also common to other pathologies (i.e., heart failure, pulmonary embolism, COPD…). Most treatments of altitude illnesses have limited value and may even be detrimental in COVID-19. Some may be efficient, potentially the corticosteroid dexamethasone. Physiological adaptations to altitude/hypoxia can exert diverse effects, depending on the constitution of the target individual and the hypoxic dose. In healthy individuals, they may optimize oxygen supply and increase mitochondrial, antioxidant, and immune system function. It is highly debated if these physiological responses to hypoxia overlap in many instances with SARS-CoV-2 infection and may exert preventive effects under very specific conditions. The temporal overlap of SARS-CoV-2 infection and exposure to altitude/hypoxia may be detrimental. No evidence-based knowledge is presently available on whether and how altitude/hypoxia may prevent, treat or aggravate COVID-19. The reported lower incidence and mortality of COVID-19 in high-altitude places remain to be confirmed. High-altitude illnesses and COVID-19 pathologies exhibit clear pathophysiological differences. While potentially effective as a prophylactic measure, altitude/hypoxia is likely associated with elevated risks for patients with COVID-19. Altogether, the different points discussed in this review are of possibly some relevance for individuals who aim to reach high-altitude areas. However, due to the ever-changing state of understanding of COVID-19, all points discussed in this review may be out of date at the time of its publication.
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Affiliation(s)
| | - Tadej Debevec
- Faculty of SportUniversity of LjubljanaLjubljanaSlovenia
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The Myometrium: From Excitation to Contractions and Labour. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1124:233-263. [PMID: 31183830 DOI: 10.1007/978-981-13-5895-1_10] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/06/2022]
Abstract
We start by describing the functions of the uterus, its structure, both gross and fine, innervation and blood supply. It is interesting to note the diversity of the female's reproductive tract between species and to remember it when working with different animal models. Myocytes are the overwhelming cell type of the uterus (>95%) and our focus. Their function is to contract, and they have an intrinsic pacemaker and rhythmicity, which is modified by hormones, stretch, paracrine factors and the extracellular environment. We discuss evidence or not for pacemaker cells in the uterus. We also describe the sarcoplasmic reticulum (SR) in some detail, as it is relevant to calcium signalling and excitability. Ion channels, including store-operated ones, their contributions to excitability and action potentials, are covered. The main pathway to excitation is from depolarisation opening voltage-gated Ca2+ channels. Much of what happens downstream of excitability is common to other smooth muscles, with force depending upon the balance of myosin light kinase and phosphatase. Mechanisms of maintaining Ca2+ balance within the myocytes are discussed. Metabolism, and how it is intertwined with activity, blood flow and pH, is covered. Growth of the myometrium and changes in contractile proteins with pregnancy and parturition are also detailed. We finish with a description of uterine activity and why it is important, covering progression to labour as well as preterm and dysfunctional labours. We conclude by highlighting progress made and where further efforts are required.
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