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Murphey JT, Temple JL, Hostler D. Taste and Appetite at Altitude: A Comprehensive Review of Sensory and Hunger Modulation in High-Altitude Environments. High Alt Med Biol 2024. [PMID: 39122250 DOI: 10.1089/ham.2024.0018] [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: 08/12/2024] Open
Abstract
Introduction: Individuals living or working at high altitudes typically experience altered taste perceptions and reduced appetite. These changes can lead to nutritional deficiencies, affecting the energy balance and body composition. Methods: We conducted a nonsystematic review of PubMed to explore these phenomena and expound on their findings to offer additional insights. Results: Changes in taste and perception are common and typically lead to loss of mass. There are limited practical solutions to mitigate these challenges. Discussion: Gradual acclimatization and tailored nutritional strategies are required to enhance health and performance in high-altitude environments. This review provides critical insights into the intersection of altitude, nutrition, and health.
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Affiliation(s)
- Joshua T Murphey
- Center for Research and Education in Special Environments, Department of Exercise and Nutrition Sciences, University at Buffalo, Buffalo, New York, USA
| | - Jennifer L Temple
- Nutrition and Health Research Laboratory, Department of Exercise and Nutrition Sciences, University at Buffalo, Buffalo, New York, USA
| | - David Hostler
- Center for Research and Education in Special Environments, Department of Exercise and Nutrition Sciences, University at Buffalo, Buffalo, New York, USA
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2
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Wang J, Liu S, Sun L, Kong Z, Chai J, Wen J, Tian X, Chen N, Xu C. Association of attenuated leptin signaling pathways with impaired cardiac function under prolonged high-altitude hypoxia. Sci Rep 2024; 14:10206. [PMID: 38702334 PMCID: PMC11068766 DOI: 10.1038/s41598-024-59559-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Accepted: 04/12/2024] [Indexed: 05/06/2024] Open
Abstract
Cardiovascular function and adipose metabolism were markedly influenced under high altitudes. However, the interplay between adipokines and heart under hypoxia remains to be elucidated. We aim to explore alterations of adipokines and underlying mechanisms in regulating cardiac function under high altitudes. We investigated the cardiopulmonary function and five adipokines in Antarctic expeditioners at Kunlun Station (4,087 m) for 20 days and established rats exposed to hypobaric hypoxia (5,000 m), simulating Kunlun Station. Antarctic expeditioners exhibited elevated heart rate, blood pressure, systemic vascular resistance, and decreased cardiac pumping function. Plasma creatine phosphokinase-MB (CK-MB) and platelet-endothelial cell adhesion molecule-1 (sPecam-1) increased, and leptin, resistin, and lipocalin-2 decreased. Plasma leptin significantly correlated with altered cardiac function indicators. Additionally, hypoxic rats manifested impaired left ventricular systolic and diastolic function, elevated plasma CK-MB and sPecam-1, and decreased plasma leptin. Chronic hypoxia for 14 days led to increased myocyte hypertrophy, fibrosis, apoptosis, and mitochondrial dysfunction, coupled with reduced protein levels of leptin signaling pathways in myocardial tissues. Cardiac transcriptome analysis revealed leptin was associated with downregulated genes involved in rhythm, Na+/K+ transport, and cell skeleton. In conclusion, chronic hypoxia significantly reduced leptin signaling pathways in cardiac tissues along with significant pathological changes, thus highlighting the pivotal role of leptin in regulation of cardiac function under high altitudes.
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Affiliation(s)
- Jianan Wang
- Institute of Basic Medical Sciences, School of Basic Medicine, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, 100005, China
| | - Shiying Liu
- Institute of Basic Medical Sciences, School of Basic Medicine, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, 100005, China
| | - Lihong Sun
- Center for Experimental Animal Research, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100005, China
| | - Zhanping Kong
- Qinghai Provincial People's Hospital, Xining, 810000, Qinghai, China
| | - Jiamin Chai
- Institute of Basic Medical Sciences, School of Basic Medicine, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, 100005, China
| | - Jigang Wen
- Institute of Basic Medical Sciences, School of Basic Medicine, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, 100005, China
| | - Xuan Tian
- Institute of Basic Medical Sciences, School of Basic Medicine, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, 100005, China
| | - Nan Chen
- Institute of Basic Medical Sciences, School of Basic Medicine, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, 100005, China
| | - Chengli Xu
- Institute of Basic Medical Sciences, School of Basic Medicine, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, 100005, China.
- Center of Environmental and Health Sciences, Chinese Academy of Medical Sciences, Beijing, 100005, China.
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Niclou A, Sarma M, Levy S, Ocobock C. To the extreme! How biological anthropology can inform exercise physiology in extreme environments. Comp Biochem Physiol A Mol Integr Physiol 2023; 284:111476. [PMID: 37423419 DOI: 10.1016/j.cbpa.2023.111476] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2023] [Revised: 07/03/2023] [Accepted: 07/04/2023] [Indexed: 07/11/2023]
Abstract
The fields of biological anthropology and exercise physiology are closely related and can provide mutually beneficial insights into human performance. These fields often use similar methods and are both interested in how humans function, perform, and respond in extreme environments. However, these two fields have different perspectives, ask different questions, and work within different theoretical frameworks and timescales. Biological anthropologists and exercise physiologists can greatly benefit from working together when examining human adaptation, acclimatization, and athletic performance in the extremes of heat, cold, and high-altitude. Here we review the adaptations and acclimatizations in these three different extreme environments. We then examine how this work has informed and built upon exercise physiology research on human performance. Finally, we present an agenda for moving forward, hopefully, with these two fields working more closely together to produce innovative research that improves our holistic understanding of human performance capacities informed by evolutionary theory, modern human acclimatization, and the desire to produce immediate and direct benefits.
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Affiliation(s)
- Alexandra Niclou
- Pennington Biomedical Research Center, Baton Rouge, LA, United States of America. https://twitter.com/fiat_luxandra
| | - Mallika Sarma
- Human Space Flight Lab, Johns Hopkins School of Medicine, Baltimore, MD, United States of America. https://twitter.com/skyy_mal
| | - Stephanie Levy
- Department of Anthropology, CUNY Hunter College, New York, NY, United States of America; New York Consortium in Evolutionary Primatology, New York, NY, United States of America. https://twitter.com/slevyscience
| | - Cara Ocobock
- University of Notre Dame Department of Anthropology, Notre Dame, IN, United States of America; Eck Institute for Global Health, Institute for Educational Initiatives, University of Notre Dame, United States of America.
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Chen CY, Chou CC, Lin KX, Mündel T, Chen MT, Liao YH, Tsai SC. A Sports Nutrition Perspective on the Impacts of Hypoxic High-Intensity Interval Training (HIIT) on Appetite Regulatory Mechanisms: A Narrative Review of the Current Evidence. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:ijerph19031736. [PMID: 35162760 PMCID: PMC8835478 DOI: 10.3390/ijerph19031736] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 01/27/2022] [Accepted: 01/30/2022] [Indexed: 01/11/2023]
Abstract
High-intensity interval training (HIIT) and low-oxygen exposure may inhibit the secretion of appetite-stimulating hormones, suppress appetite, and inhibit dietary intake. Physiological changes affecting appetite are frequent and include appetite hormone (ghrelin, leptin, PYY, and GLP-1) effects and the subjective loss of appetite, resulting in nutritional deficiencies. This paper is a narrative review of the literature to verify the HIIT effect on appetite regulation mechanisms and discusses the possible relationship between appetite effects and the need for high-intensity exercise training in a hypoxic environment. We searched MEDLINE/PubMed and the Web of Science databases, as well as English articles (gray literature by Google Scholar for English articles) through Google Scholar, and the searched studies primarily focused on the acute effects of exercise and hypoxic environmental factors on appetite, related hormones, and energy intake. In a general normoxic environment, regular exercise habits may have accustomed the athlete to intense training and, therefore, no changes occurred in their subjective appetite, but there is a significant effect on the appetite hormones. The higher the exercise intensity and the longer the duration, the more likely exercise is to cause exercise-induced appetite loss and changes in appetite hormones. It has not been clear whether performing HIIT in a hypoxic environment may interfere with the exerciser’s diet or the nutritional supplement intake as it suppresses appetite, which, in turn, affects and interferes with the recovery efficiency after exercise. Although appetite-regulatory hormones, the subjective appetite, and energy intake may be affected by exercise, such as hypoxia or hypoxic exercise, we believe that energy intake should be the main observable indicator in future studies on environmental and exercise interventions.
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Affiliation(s)
- Chung-Yu Chen
- Department of Exercise and Health Sciences, University of Taipei, Taipei City 111, Taiwan;
| | - Chun-Chung Chou
- Physical Education Office, National Taipei University of Technology, Taipei City 106, Taiwan;
| | - Ke-Xun Lin
- Department of Exercise and Health Science, National Taipei University of Nursing and Health Sciences, Taipei City 112, Taiwan;
| | - Toby Mündel
- School of Sport, Exercise and Nutrition, Massey University, Palmerston North 4442, New Zealand;
| | - Mu-Tsung Chen
- Department of Food and Beverage Management, Shih Chien University, Taipei City 104, Taiwan;
| | - Yi-Hung Liao
- Department of Exercise and Health Science, National Taipei University of Nursing and Health Sciences, Taipei City 112, Taiwan;
- Correspondence: (Y.-H.L.); (S.-C.T.)
| | - Shiow-Chwen Tsai
- Institute of Sports Sciences, University of Taipei, Taipei City 111, Taiwan
- Correspondence: (Y.-H.L.); (S.-C.T.)
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Kietzmann T, Mäkelä VH. The hypoxia response and nutritional peptides. Peptides 2021; 138:170507. [PMID: 33577839 DOI: 10.1016/j.peptides.2021.170507] [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: 12/15/2020] [Revised: 01/29/2021] [Accepted: 02/03/2021] [Indexed: 10/22/2022]
Abstract
Hypoxia controls metabolism at several levels, e.g., via mitochondrial ATP production, glucose uptake and glycolysis. Hence it is likely that hypoxia also affects the action and/or production of many peptide hormones linked to food intake and appetite control. Many of those are produced in the gastrointestinal tract, endocrine pancreas, adipose tissue, and selective areas in the brain which modulate and concert their actions. However, the complexity of the hypoxia response and the links to peptides/hormones involved in food intake and appetite control in the different organs are not well known. This review summarizes the role of the hypoxia response and its effects on major peptides linked to appetite regulation, nutrition and metabolism.
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Affiliation(s)
- Thomas Kietzmann
- University of Oulu, Faculty of Biochemistry and Molecular Medicine, Biocenter Oulu, Oulu, Finland.
| | - Ville H Mäkelä
- University of Oulu, Faculty of Biochemistry and Molecular Medicine, Biocenter Oulu, Oulu, Finland
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Du X, Girard O, Fan RY, Ma F. Effects of Active and Passive Hypoxic Conditioning for 6 Weeks at Different Altitudes on Blood Lipids, Leptin, and Weight in Rats. High Alt Med Biol 2020; 21:243-248. [PMID: 32486854 DOI: 10.1089/ham.2020.0003] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Du, Xia, Olivier Girard, Rong yun Fan, and Fuhai Ma. Effects of active and passive hypoxic conditioning for 6 weeks at different altitudes on blood lipids, leptin, and weight in rats. High Alt Med Biol. 21:243-248, 2020. Objective: To compare the effects of 6 weeks of passive and active hypoxia exposure at different altitudes on lipid metabolism, leptin, and weight in rats. Materials and Methods: Eighty 9-week-old male Wistar rats were assigned to either non-exercise or exercise groups. Each group was subdivided into four categories (n = 10) based on hypoxic conditions: 0, 2200, 2200 + 3500, and 3500 m. Rats in the exercise group trained on a treadmill at a speed of 20-22 m/min (0° incline) for 90 minutes, 5 days per week for 6 weeks. Serum lipid and leptin levels and weight were measured following the intervention. Results: Total cholesterol (-8.2% ± 3.5%), low-density lipoproteins (-29.8% ± 8.1%), and triglyceride (TG) levels (-17.2% ± 3.8%) were lower, and high-density lipoproteins (+7.4% ± 4.0%) higher, in exercise versus non-exercise groups (all p < 0.001), independent of condition. TG levels were lower at altitude (-13.0% ± 27.3%, -10.9% ± 24.3%, and -9.2% ± 20.9% at 2200, 2200 + 3500, and 3500 m, respectively) compared to 0 m (p < 0.001). Hypoxic exposure decreased leptin with lower values at 2200 + 3500 m and 3500 m compared to 0 m (p < 0.05). Weight was lower in exercise than non-exercise groups (-8.2% ± 21.0%; p < 0.001), and at altitude (-2.7% ± 2.6%, -5.5% ± 3.7%, and -5.7% ± 2.7% at 2200, 2200 + 3500, and 3500 m, respectively) compared to 0 m. Conclusion: Regular aerobic exercise led to more favorable responses for lipid metabolism and weight control than the oxygenation conditions the animals are in.
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Affiliation(s)
- Xia Du
- Qinghai Provincial Sports Bureau, Qinghai Institute of Sports Science, Xi Ning, China.,China National Sports Bureau, Key Lab of Plateau Training in China General Administration of Sport, Xi Ning, China.,Qinghai Provincial Department of Science and Technology, Excellent Key Lab of Plateau Physical Education in Qinghai Province, Xi Ning, China
| | - Olivier Girard
- School of Human Sciences, Exercise and Sport Science, The University of Western Australia, Crawley, Australia
| | - Rong Yun Fan
- Qinghai Provincial Sports Bureau, Qinghai Institute of Sports Science, Xi Ning, China.,China National Sports Bureau, Key Lab of Plateau Training in China General Administration of Sport, Xi Ning, China.,Qinghai Provincial Department of Science and Technology, Excellent Key Lab of Plateau Physical Education in Qinghai Province, Xi Ning, China
| | - Fuhai Ma
- Qinghai Provincial Sports Bureau, Qinghai Institute of Sports Science, Xi Ning, China.,China National Sports Bureau, Key Lab of Plateau Training in China General Administration of Sport, Xi Ning, China.,Qinghai Provincial Department of Science and Technology, Excellent Key Lab of Plateau Physical Education in Qinghai Province, Xi Ning, China
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Karl JP, Cole RE, Berryman CE, Finlayson G, Radcliffe PN, Kominsky MT, Murphy NE, Carbone JW, Rood JC, Young AJ, Pasiakos SM. Appetite Suppression and Altered Food Preferences Coincide with Changes in Appetite-Mediating Hormones During Energy Deficit at High Altitude, But Are Not Affected by Protein Intake. High Alt Med Biol 2018; 19:156-169. [PMID: 29431471 PMCID: PMC6014054 DOI: 10.1089/ham.2017.0155] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Accepted: 01/03/2018] [Indexed: 12/22/2022] Open
Abstract
Karl, J. Philip, Renee E. Cole, Claire E. Berryman, Graham Finlayson, Patrick N. Radcliffe, Matthew T. Kominsky, Nancy E. Murphy, John W. Carbone, Jennifer C. Rood, Andrew J. Young, and Stefan M. Pasiakos. Appetite suppression and altered food preferences coincide with changes in appetite-mediating hormones during energy deficit at high altitude, but are not affected by protein intake. High Alt Med Biol. 19:156-169, 2018.-Anorexia and unintentional body weight loss are common during high altitude (HA) sojourn, but underlying mechanisms are not fully characterized, and the impact of dietary macronutrient composition on appetite regulation at HA is unknown. This study aimed to determine the effects of a hypocaloric higher protein diet on perceived appetite and food preferences during HA sojourn and to examine longitudinal changes in perceived appetite, appetite mediating hormones, and food preferences during acclimatization and weight loss at HA. Following a 21-day level (SL) period, 17 unacclimatized males ascended to and resided at HA (4300 m) for 22 days. At HA, participants were randomized to consume measured standard-protein (1.0 g protein/kg/d) or higher protein (2.0 g/kg/d) hypocaloric diets (45% carbohydrate, 30% energy restriction) and engaged in prescribed physical activity to induce an estimated 40% energy deficit. Appetite, food preferences, and appetite-mediating hormones were measured at SL and at the beginning and end of HA. Diet composition had no effect on any outcome. Relative to SL, appetite was lower during acute HA (days 0 and 1), but not different after acclimatization and weight loss (HA day 18), and food preferences indicated an increased preference for sweet- and low-protein foods during acute HA, but for high-fat foods after acclimatization and weight loss. Insulin, leptin, and cholecystokinin concentrations were elevated during acute HA, but not after acclimatization and weight loss, whereas acylated ghrelin concentrations were suppressed throughout HA. Findings suggest that appetite suppression and altered food preferences coincide with changes in appetite-mediating hormones during energy deficit at HA. Although dietary protein intake did not impact appetite, the possible incongruence with food preferences at HA warrants consideration when developing nutritional strategies for HA sojourn.
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Affiliation(s)
- J. Philip Karl
- Military Nutrition Division, U.S. Army Research Institute of Environmental Medicine, Natick, Massachusetts
| | - Renee E. Cole
- Military Nutrition Division, U.S. Army Research Institute of Environmental Medicine, Natick, Massachusetts
| | - Claire E. Berryman
- Military Nutrition Division, U.S. Army Research Institute of Environmental Medicine, Natick, Massachusetts
- Oak Ridge Institute of Science and Education, Oak Ridge, Tennessee
| | - Graham Finlayson
- School of Psychology, University of Leeds, Leeds, United Kingdom
| | - Patrick N. Radcliffe
- Military Nutrition Division, U.S. Army Research Institute of Environmental Medicine, Natick, Massachusetts
- Oak Ridge Institute of Science and Education, Oak Ridge, Tennessee
| | - Matthew T. Kominsky
- Military Nutrition Division, U.S. Army Research Institute of Environmental Medicine, Natick, Massachusetts
| | - Nancy E. Murphy
- Military Nutrition Division, U.S. Army Research Institute of Environmental Medicine, Natick, Massachusetts
| | - John W. Carbone
- Oak Ridge Institute of Science and Education, Oak Ridge, Tennessee
- School of Health Sciences, Eastern Michigan University, Ypsilanti, Michigan
| | | | - Andrew J. Young
- Military Nutrition Division, U.S. Army Research Institute of Environmental Medicine, Natick, Massachusetts
- Oak Ridge Institute of Science and Education, Oak Ridge, Tennessee
| | - Stefan M. Pasiakos
- Military Nutrition Division, U.S. Army Research Institute of Environmental Medicine, Natick, Massachusetts
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Matu J, Gonzalez JT, Ispoglou T, Duckworth L, Deighton K. The effects of hypoxia on hunger perceptions, appetite-related hormone concentrations and energy intake: A systematic review and meta-analysis. Appetite 2018; 125:98-108. [DOI: 10.1016/j.appet.2018.01.015] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 01/11/2018] [Accepted: 01/12/2018] [Indexed: 02/06/2023]
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Rausch LK, Hofer M, Pramsohler S, Kaser S, Ebenbichler C, Haacke S, Gatterer H, Netzer NC. Adiponectin, Leptin and Visfatin in Hypoxia and its Effect for Weight Loss in Obesity. Front Endocrinol (Lausanne) 2018; 9:615. [PMID: 30405530 PMCID: PMC6200908 DOI: 10.3389/fendo.2018.00615] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Accepted: 09/27/2018] [Indexed: 11/13/2022] Open
Abstract
Rationale: Hypoxia induces leptin gene expression in human adipocytes via hypoxia-inducible factors (HIF-α/β). Under ambient moderate hypoxia, leptin in adipocytes is elevated for at least 14 days. Leptin is supposedly involved in the reduced food intake, increased utilization of fatty acids for energy production and possible weight loss observed at high altitudes. Literature on adiponectin and visfatin in high altitude is inconsistent with reports of elevated levels and non-elevated levels. Exercise in hypoxia studies in obese subjects have shown a significant weight loss after up to 3 weeks, but it is unclear if this effect holds up for longer time periods. Therefore, we aimed to investigate 32 obese subjects completing 52 exercise and rest sessions within 8 months at either moderate or sham hypoxia and to analyze leptin, adiponectin, and visfatin mRNA-expression at different time points of exposure. Methods: Abdominal subcutaneous fat biopsies were taken from 32 obese subjects before, after 3 months and after 8 months of intervention. Subjects were randomly divided into two groups and exercised at moderate intensity at two different study sites twice a week. The IG was exposed to normobaric hypoxia (FiO2: 14.0 ± 0.2%,) at exercise and at rest (FiO2: 12.0 ± 0.2%) and the CG to sham hypoxia. Quantitative real-time polymerase chain reaction (qPCR) was used in order to determine mRNA-levels of leptin, adiponectin, and visfatin. Results: No differences in leptin levels after 3 and 8 months compared to baseline and between groups were found. There was no significant difference regarding adiponectin or visfatin at any time point compared to baseline in the hypoxia group, but an increase after 3 months was seen in the control group at normoxia compared to the hypoxia group (adiponectin: p = 0.029 and visfatin: p = 0.014). Conclusion: In this first several months' duration randomized sham controlled hypoxia exercise and rest study with obese subjects, we found no time extended leptin mRNA-expression in subjects under hypoxia after 3 and 8 months compared to baseline levels. Moderate exercise in normoxia not in hypoxia leads to elevated adiponectin and visfatin levels after 3 months.
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Affiliation(s)
- Linda K Rausch
- Hermann Buhl Institute for Hypoxia and Sleep Medicine Research, Bad Aibling, Germany
- Department Sports Science, University Innsbruck, Tirol, Austria
| | - Maximilian Hofer
- Department of Internal Medicine 1, Medical University of Innsbruck, Tirol, Austria
- CD Laboratory for Metabolic Crosstalk, Department of Internal Medicine 1, Medical University of Innsbruck, Tirol, Austria
| | - Stephan Pramsohler
- Hermann Buhl Institute for Hypoxia and Sleep Medicine Research, Bad Aibling, Germany
| | - Susanne Kaser
- Department of Internal Medicine 1, Medical University of Innsbruck, Tirol, Austria
- CD Laboratory for Metabolic Crosstalk, Department of Internal Medicine 1, Medical University of Innsbruck, Tirol, Austria
| | | | | | - Hannes Gatterer
- Institute for Mountain Emergency Medicine, Eurac Research, Bozen, Italy
| | - Nikolaus C Netzer
- Hermann Buhl Institute for Hypoxia and Sleep Medicine Research, Bad Aibling, Germany
- Department Sports Science, University Innsbruck, Tirol, Austria
- Institute for Mountain Emergency Medicine, Eurac Research, Bozen, Italy
- Division of Sports Medicine and Rehabilitation, Department of Medicine, University Ulm, Ulm, Germany
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10
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Bhatnagar A. Response by Bhatnagar to Letter Regarding Article, "Environmental Determinants of Cardiovascular Disease". Circ Res 2017; 121:e81-e82. [PMID: 28963194 DOI: 10.1161/circresaha.117.311811] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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11
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Debevec T. Hypoxia-Related Hormonal Appetite Modulation in Humans during Rest and Exercise: Mini Review. Front Physiol 2017; 8:366. [PMID: 28611686 PMCID: PMC5447736 DOI: 10.3389/fphys.2017.00366] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Accepted: 05/17/2017] [Indexed: 12/25/2022] Open
Abstract
Obesity is associated with numerous chronic ailments and represents one of the major health and economic issues in the modernized societies. Accordingly, there is an obvious need for novel treatment approaches. Recently, based on the reports of reduced appetite and subsequent weight loss following high-altitude sojourns, exposure to hypoxia has been proposed as a viable weight-reduction strategy. While altitude-related appetite modulation is complex and not entirely clear, hypoxia-induced alterations in hormonal appetite modulation might be among the key underlying mechanisms. The present paper summarizes the up-to-date research on hypoxia/altitude-induced changes in the gut and adipose tissue derived peptides related to appetite regulation. Orexigenic hormone ghrelin and anorexigenic peptides leptin, glucagon-like peptide-1, peptide YY, and cholecystokinin have to-date been investigated as potential modulators of hypoxia-driven appetite alterations. Current evidence suggests that hypoxia can, especially acutely, lead to decreased appetite, most probably via reduction of acylated ghrelin concentration. Hypoxia-related short and long-term changes in other hormonal markers are more unclear although hypoxia seems to importantly modulate leptin levels, especially following prolonged hypoxic exposures. Limited evidence also suggests that different activity levels during exposures to hypoxia do not additively affect hormonal appetite markers. Although very few studies have been performed in obese/overweight individuals, the available data indicate that hypoxia/altitude exposures do not seem to differentially affect appetite regulation via hormonal pathways in this cohort. Given the lack of experimental data, future well-controlled acute and prolonged studies are warranted to expand our understanding of hypoxia-induced hormonal appetite modulation and its kinetics in health and disease.
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Affiliation(s)
- Tadej Debevec
- Department of Automation, Biocybernetics and Robotics, Jozef Stefan InstituteLjubljana, Slovenia
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12
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Díaz-Gutiérrez J, Martínez-González MÁ, Pons Izquierdo JJ, González-Muniesa P, Martínez JA, Bes-Rastrollo M. Living at Higher Altitude and Incidence of Overweight/Obesity: Prospective Analysis of the SUN Cohort. PLoS One 2016; 11:e0164483. [PMID: 27812092 PMCID: PMC5094724 DOI: 10.1371/journal.pone.0164483] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Accepted: 09/25/2016] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Residence at high altitude has been associated with lower obesity rates probably due to hypoxia conditions. However, there is no evidence of this association in a free-living population. OBJECTIVES We assessed the association between the altitude where each participant of a Spanish cohort (the SUN Project) was living and the incidence of overweight/obesity. METHODS The SUN Project is a dynamic, prospective, multipurpose cohort of Spanish university graduates with a retention rate of 89%. We included in the analysis 9 365 participants free of overweight/obesity at baseline. At the baseline questionnaire, participants reported their postal code and the time they had been living in their city/village. We imputed the altitude of each postal code according to the data of the Spanish National Cartographic Institute and categorized participants in tertiles. We used Cox regression models to adjust for potential confounding variables. RESULTS During a median follow-up of 10 years, we identified 2 156 incident cases of overweight/obesity. After adjusting for sex, age, time of residence at current city, baseline body mass index, physical activity, sedentarism and years of education (≤ 3 years, ≥ 4 years, Master/PhD), those participants in the third tertile (>456 m) exhibited a statistically significant 14% reduction in the risk of developing overweight/obesity in comparison to those in the first tertile (<124 m) (adjusted HR = 0.86; 95% CI: 0.77, 0.96). CONCLUSIONS Living in cities of higher altitude was inversely associated with the risk of developing overweight/obesity in a cohort of Spanish university graduates.
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Affiliation(s)
- Jesús Díaz-Gutiérrez
- University of Navarra, Department of Preventive Medicine and Public Health, School of Medicine, Pamplona, Spain
| | - Miguel Ángel Martínez-González
- University of Navarra, Department of Preventive Medicine and Public Health, School of Medicine, Pamplona, Spain
- IDISNA Navarra’s Health Research Institute, Pamplona, Spain
- CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), Instituto de Salud Carlos III, Madrid, Spain
- Harvard TH Chan School of Public Health, Boston, United States of America
| | - Juan José Pons Izquierdo
- University of Navarra, Department of History, Art History, and Geography, School of Humanities and Social Sciences, Pamplona, Spain
| | - Pedro González-Muniesa
- IDISNA Navarra’s Health Research Institute, Pamplona, Spain
- CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), Instituto de Salud Carlos III, Madrid, Spain
- University of Navarra, Department of Nutrition and Food Sciences and Physiology, School of Pharmacy, Pamplona, Spain
| | - J. Alfredo Martínez
- IDISNA Navarra’s Health Research Institute, Pamplona, Spain
- CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), Instituto de Salud Carlos III, Madrid, Spain
- University of Navarra, Department of Nutrition and Food Sciences and Physiology, School of Pharmacy, Pamplona, Spain
| | - Maira Bes-Rastrollo
- University of Navarra, Department of Preventive Medicine and Public Health, School of Medicine, Pamplona, Spain
- IDISNA Navarra’s Health Research Institute, Pamplona, Spain
- CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), Instituto de Salud Carlos III, Madrid, Spain
- * E-mail:
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Mekjavic IB, Amon M, Kölegård R, Kounalakis SN, Simpson L, Eiken O, Keramidas ME, Macdonald IA. The Effect of Normobaric Hypoxic Confinement on Metabolism, Gut Hormones, and Body Composition. Front Physiol 2016; 7:202. [PMID: 27313541 PMCID: PMC4889598 DOI: 10.3389/fphys.2016.00202] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Accepted: 05/18/2016] [Indexed: 12/16/2022] Open
Abstract
To assess the effect of normobaric hypoxia on metabolism, gut hormones, and body composition, 11 normal weight, aerobically trained (O2peak: 60.6 ± 9.5 ml·kg−1·min−1) men (73.0 ± 7.7 kg; 23.7 ± 4.0 years, BMI 22.2 ± 2.4 kg·m−2) were confined to a normobaric (altitude ≃ 940 m) normoxic (NORMOXIA; PIO2 ≃ 133.2 mmHg) or normobaric hypoxic (HYPOXIA; PIO was reduced from 105.6 to 97.7 mmHg over 10 days) environment for 10 days in a randomized cross-over design. The wash-out period between confinements was 3 weeks. During each 10-day period, subjects avoided strenuous physical activity and were under continuous nutritional control. Before, and at the end of each exposure, subjects completed a meal tolerance test (MTT), during which blood glucose, insulin, GLP-1, ghrelin, peptide-YY, adrenaline, noradrenaline, leptin, and gastro-intestinal blood flow and appetite sensations were measured. There was no significant change in body weight in either of the confinements (NORMOXIA: −0.7 ± 0.2 kg; HYPOXIA: −0.9 ± 0.2 kg), but a significant increase in fat mass in NORMOXIA (0.23 ± 0.45 kg), but not in HYPOXIA (0.08 ± 0.08 kg). HYPOXIA confinement increased fasting noradrenaline and decreased energy intake, the latter most likely associated with increased fasting leptin. The majority of all other measured variables/responses were similar in NORMOXIA and HYPOXIA. To conclude, normobaric hypoxic confinement without exercise training results in negative energy balance due to primarily reduced energy intake.
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Affiliation(s)
- Igor B Mekjavic
- Department of Automation, Biocybernetics and Robotics, Jožef Stefan InstituteLjubljana, Slovenia; Department of Biomedical Physiology and Kinesiology, Simon Fraser UniversityBurnaby, BC, Canada
| | - Mojca Amon
- Jožef Stefan International Postgraduate School Ljubljana, Slovenia
| | - Roger Kölegård
- Department of Environmental Physiology, Swedish Aerospace Physiology Center, School of Technology and Health, Royal Institute of Technology Stockholm, Sweden
| | - Stylianos N Kounalakis
- Human Performance-Rehabilitation Laboratory, Faculty of Physical and Cultural Education, Hellenic Military University Vari, Greece
| | - Liz Simpson
- Metabolic Physiology Group, Faculty of Medicine and Health Sciences, University of Nottingham Queen's Medical Centre Nottingham, UK
| | - Ola Eiken
- Department of Environmental Physiology, Swedish Aerospace Physiology Center, School of Technology and Health, Royal Institute of Technology Stockholm, Sweden
| | - Michail E Keramidas
- Department of Environmental Physiology, Swedish Aerospace Physiology Center, School of Technology and Health, Royal Institute of Technology Stockholm, Sweden
| | - Ian A Macdonald
- Metabolic Physiology Group, Faculty of Medicine and Health Sciences, University of Nottingham Queen's Medical Centre Nottingham, UK
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Morishima T, Goto K. Ghrelin, GLP-1, and leptin responses during exposure to moderate hypoxia. Appl Physiol Nutr Metab 2015; 41:375-81. [PMID: 26863323 DOI: 10.1139/apnm-2015-0311] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Severe hypoxia has been indicated to cause acute changes in appetite-related hormones, which attenuate perceived appetite. However, the effects of moderate hypoxia on appetite-related hormonal regulation and perceived appetite have not been elucidated. Therefore, we examined the effects of moderate hypoxia on appetite-related hormonal regulation and perceived appetite. Eight healthy males (21.0 ± 0.6 years; 173 ± 2.3 cm; 70.6 ± 5.0 kg; 23.4 ± 1.1 kg/m(2)) completed two experimental trials on separate days: a rest trial in normoxia (FiO2 = 20.9%) and a rest trial in hypoxia (FiO2 = 15.0%). The experimental trials were performed over 7 h in an environmental chamber. Blood samples and scores of subjective appetite were collected over 7 h. Standard meals were provided 1 h (745 kcal) and 4 h (731 kcal) after initiating exposure to hypoxia or normoxia within the chamber. Although each meal significantly reduced plasma active ghrelin concentrations (P < 0.05), the response did not differ significantly between the trials over 7 h. No significant differences in the area under the curves for plasma active ghrelin concentrations over 7 h were observed between the two trials. No significant differences were observed in glucagon-like peptide 1 or leptin concentrations over 7 h between the trials. The subjective feeling of hunger and fullness acutely changed in response to meal ingestions. However, these responses were not affected by exposure to moderate hypoxia. In conclusion, 7 h of exposure to moderate hypoxia did not change appetite-related hormonal responses or perceived appetite in healthy males.
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Affiliation(s)
- Takuma Morishima
- a Faculty of Sport and Health Science, Ritsumeikan University, 1-1-1, Nojihigashi, Kusatsu, Shiga, 525-8577, Japan.,b Research Fellow of the Japan Society for the Promotion of Science, 5-3-1 Kojimachi, Chiyoda-ku, Tokyo 102-0083, Japan
| | - Kazushige Goto
- a Faculty of Sport and Health Science, Ritsumeikan University, 1-1-1, Nojihigashi, Kusatsu, Shiga, 525-8577, Japan
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Mohajeri S, Perkins BA, Brubaker PL, Riddell MC. Diabetes, trekking and high altitude: recognizing and preparing for the risks. Diabet Med 2015; 32:1425-37. [PMID: 25962798 DOI: 10.1111/dme.12795] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/07/2015] [Indexed: 12/25/2022]
Abstract
Although regular physical activity is encouraged for individuals with diabetes, exercise at high altitude increases risk for a number of potential complications. This review highlights our current understanding of the key physiological and clinical issues that accompany high-altitude travel and proposes basic clinical strategies to help overcome obstacles faced by trekkers with Type 1 or Type 2 diabetes. Although individuals with diabetes have adaptations to the hypoxia of high altitude (increased ventilation, heart rate, blood pressure and hormonal responses), elevated counter-regulatory hormones can impair glycaemic control, particularly if mountain sickness occurs. Moreover, high-altitude-induced anorexia and increased energy expenditure can predispose individuals to dysglycaemia unless careful adjustments in medication are performed. Frequent blood glucose monitoring is imperative, and results must be interpreted with caution because capillary blood glucose meter results may be less accurate at high elevations and low temperatures. It is also important to undergo pre-travel screening to rule out possible contraindications owing to chronic diabetes complications and make well-informed decisions about risks. Despite the risks, healthy, physically fit and well-prepared individuals with Type 1 or Type 2 diabetes who are capable of advanced self-management can be encouraged to participate in these activities and attain their summit goals. Moreover, trekking at high altitude can serve as an effective means to engage in physical activity and to increase confidence with fundamental diabetes self-management skills.
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Affiliation(s)
- S Mohajeri
- School of Kinesiology and Health Science, Muscle Health Research Centre and Physical Activity and Chronic Disease Unit, York University, Toronto
| | - B A Perkins
- Division of Endocrinology and Department of Medicine, University of Toronto
| | - P L Brubaker
- Department of Physiology and Department of Medicine, University of Toronto, Toronto, Canada
| | - M C Riddell
- School of Kinesiology and Health Science, Muscle Health Research Centre and Physical Activity and Chronic Disease Unit, York University, Toronto
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Moreau J, Ciriello J. Effects of acute intermittent hypoxia on energy balance and hypothalamic feeding pathways. Neuroscience 2013; 253:350-60. [DOI: 10.1016/j.neuroscience.2013.09.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2013] [Revised: 09/03/2013] [Accepted: 09/04/2013] [Indexed: 01/20/2023]
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Vats P, Singh VK, Singh SN, Singh SB. High altitude induced anorexia: Effect of changes in leptin and oxidative stress levels. Nutr Neurosci 2013; 10:243-9. [DOI: 10.1080/10284150701722299] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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Shukla V, Singh SN, Vats P, Singh VK, Singh SB, Banerjee PK. Ghrelin and leptin levels of sojourners and acclimatized lowlanders at high altitude. Nutr Neurosci 2013; 8:161-5. [PMID: 16117183 DOI: 10.1080/10284150500132823] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The circulatory levels of two appetite regulatory hormones i.e. leptin and ghrelin were estimated in sojourners and acclimatized subjects to investigate their possible role in high altitude (HA) induced anorexia. A group of 30 lowlanders who had never visited HA were inducted to a height of 3600 m by air and after 48 h they were further taken to an altitude of 4300 m by road. Blood samples were collected after 48 h stay at 3600 m and again after 48 h and 7 days of stay at 4300 m during 0700-0730 h. There was a decrease in energy intake (850 kcal/day) of sojourners, which resulted in loss of body weight by 2.12 kg at HA. At an altitude of 4300 m there was a significant increase in leptin over basal levels (54.9%, p < 0.001) at 48 h that persisted even after 7 days of stay at this altitude. Ghrelin levels of sojourners decreased by more than 30% in comparison to basal values at 48 h of ascent to HA. Leptin levels of acclimatized lowlanders were also higher in comparison with control group (acclimatized group 7.6 + 0.6 ng/ml vs. control 5.6 + 0.5 ng/ml, p < 0.01, n = 50).
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Affiliation(s)
- Vasudha Shukla
- Defence Institute of Physiology and Allied Sciences, Lucknow Road, Timarpur, Delhi 110 054, India
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Kayser B, Verges S. Hypoxia, energy balance and obesity: from pathophysiological mechanisms to new treatment strategies. Obes Rev 2013; 14:579-92. [PMID: 23551535 DOI: 10.1111/obr.12034] [Citation(s) in RCA: 106] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2012] [Revised: 02/22/2013] [Accepted: 03/02/2013] [Indexed: 12/17/2022]
Abstract
High altitude exposure is often accompanied by weight loss. Postulated mechanisms are a reduction of nutritional energy intake, a reduction of intestinal energy uptake from impaired intestinal function and increased energy expenditure. Beyond the field of altitude, there are good reasons for renewed interest in the relationship between hypoxia and energy balance. The increasing prevalence of obesity and associated comorbidities represent a major health concern. Obesity is frequently associated with sleep disorders leading to intermittent systemic hypoxia with deleterious cardiovascular and metabolic consequences. Hypoxic regions may be present within hypertrophic white adipose tissue leading to chronic systemic inflammation. Among the increasing number of people commuting to altitude for work or leisure, obesity is a risk factor for acute mountain sickness. Paradoxically, exposure to intermittent hypoxia might be considered as a means to lose body mass and to improve metabolic risk factors. Daytime exposure to intermittent hypoxia has been used to treat hypertension in former Soviet Union countries and is now being experimented elsewhere. Such intermittent hypoxic exposure at rest or during exercise may lead to improvement in body composition and health status with improved exercise tolerance, metabolism and systemic arterial pressure. Future research should confirm whether hypoxic training could be a new treatment strategy for weight loss and comorbidities in obese subjects and elucidate the underlying mechanisms and signalling pathways.
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Affiliation(s)
- B Kayser
- Institute of Movement Science and Sports Medicine, Faculty of medicine, University of Geneva, Geneva, Switzerland.
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de León AC, González DA, Del Cristo Rodríguez Pérez M, Díaz BB, Méndez LIP, Aguirre-Jaime A. Leptin Concentration Declines as Altitude Increases. ACTA ACUST UNITED AC 2012. [DOI: 10.1038/oby.2005.69] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Sierra-Johnson J, Snyder EM, Johnson BD. Altitude Exposure Should Increase Serum Leptin Levels in Healthy Adults. ACTA ACUST UNITED AC 2012; 13:635-6; author reply 636-7. [PMID: 15833950 DOI: 10.1038/oby.2005.68] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Riedl S, Kluge M, Schweitzer K, Waldhör T, Frisch H. Adaptation of ghrelin and the GH/IGF axis to high altitude. Eur J Endocrinol 2012; 166:969-76. [PMID: 22416077 DOI: 10.1530/eje-12-0007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
OBJECTIVE High altitude (HA) provokes a variety of endocrine adaptive processes. We investigated the impact of HA on ghrelin levels and the GH/IGF axis. DESIGN Observational study as part of a medical multidisciplinary project in a mountainous environment. METHODS Thirty-three probands (12 females) were investigated at three timepoints during ascent to HA (A: d -42, 120 m; B: d +4, 3440 m; C: d +14, 5050 m). The following parameters were obtained: ghrelin; GH; GH-binding protein (GHBP); IGF1; IGF2; IGF-binding proteins (IGFBPs) -1, -2, and -3; acid-labile subunit (ALS); and insulin. Weight was monitored and general well being assessed using the Lake Louise acute mountain sickness (AMS) score. RESULTS Ghrelin (150 VS 111PG/ML; P0.01) and GH (3.4 VS 1.7G/L; P0.01) were significantly higher at timepoint C compared with A whereas GHBP, IGF1, IGF2, IGFBP3, ALS, and insulin levels did not change. IGFBP1 (58 VS 47G/L; P0.05) and, even more pronounced, IGFBP2 (1141 VS 615G/L; P0.001) increased significantly. No correlation, neither sex-specific nor in the total group, between individual weight loss (females: -2.1 kg; males: -5.1 kg) and rise in ghrelin was found. Five of the subjects did not reach investigation point C due to AMS. CONCLUSIONS After 14 days of exposure to HA, we observed a significant ghrelin and GH increase without changes in GHBP, IGF1, IGF2, IGFBP3, ALS, and insulin. Higher GH seems to be needed for acute metabolic effects rather than IGF/IGFBP3 generation. Increased IGFBP1 and -2 may reflect effects from HA on IGF bioavailability.
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Affiliation(s)
- Stefan Riedl
- Pediatric Department, St Anna Children's Hospital, Medical University of Vienna, Kinderspitalgasse 6, Vienna, Austria.
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de León AC, Pérez MDCR, González DA, Díaz BB, Coello SD, Hernández AG, Aguirre-Jaime A. Hemodynamics and metabolism at low versus moderate altitudes. High Alt Med Biol 2012; 12:179-86. [PMID: 21718166 DOI: 10.1089/ham.2010.1078] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Despite the higher prevalence of diabetes and hypertension in populations residing at moderate altitudes, mortality in these populations is lower than in populations residing at low altitudes. To examine whether metabolic and hemodynamic differences can explain this apparent paradox, we performed a cross-sectional study of a general population sample recruited in the Canary Islands, Spain (n=6729). We recorded altitude of residence, age, heart rate, blood pressure, body mass index, social class, physical activity, energy intake, alcohol intake, smoking habit, prevalence of type 2 diabetes mellitus and hypertension. In a subsample (n=903), we recorded serum concentration of cholesterol, triglycerides, glucose, C peptide, leptin, soluble leptin receptor (sObR), C-reactive protein, resistin, soluble CD40 ligand (sCD40L), and paraoxonase activity (PON), and we estimated insulin resistance and free leptin index. We found an inverse association between altitude and heart rate (p<0.001), leptin (p<0.001), free leptin index (p<0.001), resistin (p<0.001), and sCD40L (p<0.05) and a direct association between altitude and hypertension (odds ratio=1.29 for altitude >600 m; 95% confidence interval=1.03-1.62), glycemia (p<0.05), C peptide (p<0.001), insulin resistance (p<0.001), sObR (p<0.05), and PON (p<0.05). When social class was included in the multivariate model, the association with PON was no longer significant. In conclusion, individuals residing at moderate altitudes have a lower heart rate and lower serum concentration of total leptin, free leptin, and sCD40L. These differences may partially explain the lower mortality in these populations.
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Affiliation(s)
- Antonio Cabrera de León
- Unidad de Investigación del Hospital Universitario, Nuestra Señora de Candelaria y de Atención Primaria, Tenerife, Spain.
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Sun ZQ, Lian HJ, Zhao J, Zhang JS. Simulated high-altitude hypobaric hypoxia decreases serum and gastric levels of ghrelin in rats. Shijie Huaren Xiaohua Zazhi 2011; 19:1726-1730. [DOI: 10.11569/wcjd.v19.i16.1726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To investigate the effect of simulated high-altitude hypobaric hypoxia on serum and gastric levels of ghrelin in rats and to provide experimental evidence regarding the effect of high-altitude hypobaric hypoxia environment on digestive system function.
METHODS: Thirty Sprague-Dawley rats were randomly divided into three groups and exposed to ground level (control group) and a simulated altitude of 3 000 m and 5 000 m for 24 hours, respectively. ELISA was used to detect serum ghrelin levels, while the localization and expression of ghrelin in rat gastric mucosa were detected by immunohistochemistry. The density of gastric mucosal ghrelin immunoreactive cells in gastric mucosa was compared among each group.
RESULTS: Serum ghrelin concentrations in rats exposed to a simulated altitude of 3000 m and 5000 m were significantly lower than that in control rats (7.45 μg/L ± 1.33 μg/L, 6.87 μg/L ± 1.32 μg/L vs 9.31 μg/L ± 1.65 μg/L; P < 0.05, 0.01). Ghrelin immunoreactive cells were distributed in the X/A-like cells and endocrine cells of the fundic gastric glands, and the positive staining signals were mainly located in the cytoplasm. The integrated optical density of ghrelin immunoreactive cells in rats exposed to a simulated altitude of 3000 m and 5000 m was significantly lower than that in control rats (103.9 ± 9.55, 97.7 ± 11.22 vs 119.9 ± 11.96; both P < 0.01).
CONCLUSION: Simulated acute hypobaric hypoxia reduces serum and gastric levels of ghrelin in rats, suggesting that ghrelin might be involved in the regulation of digestive system dysfunction in hypobaric hypoxia environment.
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Manzar D, Hussain ME. Leptin rhythmicity and its relationship with other rhythm markers. BIOL RHYTHM RES 2011. [DOI: 10.1080/09291011003759558] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Qin L, Xiang Y, Song Z, Jing R, Hu C, Howard ST. RETRACTED: Erythropoietin as a possible mechanism for the effects of intermittent hypoxia on bodyweight, serum glucose and leptin in mice. ACTA ACUST UNITED AC 2010; 165:168-73. [DOI: 10.1016/j.regpep.2010.07.163] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2010] [Revised: 07/02/2010] [Accepted: 07/12/2010] [Indexed: 01/05/2023]
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Lippl FJ, Neubauer S, Schipfer S, Lichter N, Tufman A, Otto B, Fischer R. Hypobaric hypoxia causes body weight reduction in obese subjects. Obesity (Silver Spring) 2010; 18:675-81. [PMID: 20134417 DOI: 10.1038/oby.2009.509] [Citation(s) in RCA: 117] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The reason for weight loss at high altitudes is largely unknown. To date, studies have been unable to differentiate between weight loss due to hypobaric hypoxia and that related to increased physical exercise. The aim of our study was to examine the effect of hypobaric hypoxia on body weight at high altitude in obese subjects. We investigated 20 male obese subjects (age 55.7 +/- 4.1 years, BMI 33.7 +/- 1.0 kg/m(2)). Body weight, waist circumference, basal metabolic rate (BMR), nutrition protocols, and objective activity parameters as well as metabolic and cardiovascular parameters, blood gas analysis, leptin, and ghrelin were determined at low altitude (LA) (Munich 530 m, D1), at the beginning and at the end of a 1-week stay at high altitude (2,650 m, D7 and D14) and 4 weeks after returning to LA (D42). Although daily pace counting remained stable at high altitude, at D14 and D42, participants weighed significantly less and had higher BMRs than at D1. Food intake was decreased at D7. Basal leptin levels increased significantly at high altitude despite the reduction in body weight. Diastolic blood pressure was significantly lower at D7, D14, and D42 compared to D1. This study shows that obese subjects lose weight at high altitudes. This may be due to a higher metabolic rate and reduced food intake. Interestingly, leptin levels rise in high altitude despite reduced body weight. Hypobaric hypoxia seems to play a major role, although the physiological mechanisms remain unclear. Weight loss at high altitudes was associated with clinically relevant improvements in diastolic blood pressure.
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Affiliation(s)
- Florian J Lippl
- Division of Gastroenterology, Department of Internal Medicine, University Hospital of Ludwig-Maximilians-University, Munich, Germany.
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Kelly KR, Williamson DL, Fealy CE, Kriz DA, Krishnan RK, Huang H, Ahn J, Loomis JL, Kirwan JP. Acute altitude-induced hypoxia suppresses plasma glucose and leptin in healthy humans. Metabolism 2010; 59:200-5. [PMID: 19765784 PMCID: PMC2813366 DOI: 10.1016/j.metabol.2009.07.014] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/13/2009] [Revised: 07/10/2009] [Accepted: 07/15/2009] [Indexed: 01/03/2023]
Abstract
To examine the effects of acute altitude-induced hypoxia on the hormonal and metabolic response to ingested glucose, 8 young, healthy subjects (5 men and 3 women; age, 26 +/- 2 years; body mass index, 23.1 +/- 1.0 kg/m(2)) performed 2 randomized trials in a hypobaric chamber where a 75-g glucose solution was ingested under simulated altitude (ALT, 4300 m) or ambient (AMB, 362 m) conditions. Plasma glucose, insulin, C-peptide, epinephrine, leptin, and lactate concentrations were measured at baseline and 30, 60, 90, and 120 minutes after glucose ingestion during both trials. Compared with AMB, the plasma glucose response to glucose ingestion was reduced during the ALT trial (P = .04). There were no differences in the insulin and C-peptide responses between trials or in insulin sensitivity based on the homeostasis model assessment of insulin resistance. Epinephrine and lactate were both elevated during the ALT trial (P < .05), whereas the plasma leptin response was reduced compared with AMB (P < .05). The data suggest that the plasma glucose response is suppressed at ALT, but this is not due to insulin per se because insulin and C-peptide levels were similar for both trials. Elevated plasma epinephrine and lactate during ALT are indicative of increased glycogenolysis, which may have masked the magnitude of the reduced glucose response. We conclude that, during acute altitude exposure, there is a rapid metabolic response that is accompanied by a shift in the hormonal milieu that appears to favor increased glucose utilization.
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Affiliation(s)
- Karen R. Kelly
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195
- Department of Nutrition, Case Western Reserve University School of Medicine, Cleveland, OH 44109
| | - David L. Williamson
- Division of Exercise Physiology, West Virginia University School of Medicine, Morgantown, WV 26506
| | - Ciarán E. Fealy
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195
| | - David A. Kriz
- Noll Physiological Research Center, Pennsylvania State University, University Park, PA 16802
| | - Raj K. Krishnan
- Noll Physiological Research Center, Pennsylvania State University, University Park, PA 16802
| | - Hazel Huang
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195
| | - Janice Ahn
- Department of Nutrition, Case Western Reserve University School of Medicine, Cleveland, OH 44109
| | - Joseph L. Loomis
- Noll Physiological Research Center, Pennsylvania State University, University Park, PA 16802
| | - John P. Kirwan
- Department of Pathobiology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195
- Department of Nutrition, Case Western Reserve University School of Medicine, Cleveland, OH 44109
- Department of Gastroenterology/Hepatology, Cleveland Clinic, Cleveland, OH 44195
- Department of Physiology, Case Western Reserve University School of Medicine, Cleveland, OH 44109
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Baze MM, Schlauch K, Hayes JP. Gene expression of the liver in response to chronic hypoxia. Physiol Genomics 2010; 41:275-88. [PMID: 20103700 DOI: 10.1152/physiolgenomics.00075.2009] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Hypoxia is an important ecological, evolutionary, and biomedical stressor. While physiological acclimatization of mammals to hypoxia is well studied, the variation in gene expression that underlies acclimatization is not well studied. We acclimatized inbred mice for 32 days to hypoxic conditions that simulated altitudes of 1400, 3000, and 4500 m. We used oligonucleotide microarrays to measure changes in steady-state abundance of mRNA in the livers of these mice. Mice exposed to more severe hypoxia (simulated altitude of 4500 m) were smaller in mass and had higher hematocrit than mice exposed to less severe hypoxia. ANOVA and false discovery rate tests indicated that 580 genes were significantly differentially expressed in response to chronic hypoxia. Few of these 580 genes have previously been reported to respond to hypoxia. In contrast, many of these 580 genes belonged to same functional groups typically respond to acute hypoxia. That is, both chronic and acute hypoxia elicit changes in transcript abundance for genes involved in angiogenesis, glycolysis, lipid metabolism, carbohydrate metabolism, and protein amino acid phosphorylation, but the particular genes affected by the two types of hypoxia were mostly different. Numerous genes affecting the immune system were differentially expressed in response to chronic hypoxia, which supports recently proposed hypotheses that link immune function and hypoxia. Furthermore, our results discovered novel elevated mRNA abundance of genes involved in hematopoiesis and oxygen transport not reported previously, but consistent with extreme hematocrits found in hypoxic mice.
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Affiliation(s)
- Monica M Baze
- Program in Ecology, Evolution and Conservation Biology and Department of Biology, and
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Schmoller A, Voss M, Gehring H, Rudolf S, Schweiger U, Schultes B, Oltmanns KM. Short Hypoxia Does not Affect Plasma Leptin in Healthy Men under Euglycemic Clamp Conditions. Int J Endocrinol 2009; 2009:270698. [PMID: 19946426 PMCID: PMC2778504 DOI: 10.1155/2009/270698] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2009] [Accepted: 03/12/2009] [Indexed: 02/04/2023] Open
Abstract
Leptin is involved in the endocrine control of energy expenditure and body weight regulation. Previous studies emphasize a relationship between hypoxic states and leptin concentrations. The aim of this study was to investigate the effects of acute hypoxia on leptin concentrations in healthy subjects. We examined 14 healthy men. Hypoxic conditions were induced by decreasing oxygen saturation to 75% for 30 minutes. Plasma leptin concentrations were determined at baseline, after 3 hours of euglycemic clamping, during hypoxia, and repeatedly the following 2.5 hours thereafter. Our results show an increase of plasma leptin concentrations in the course of 6 hours of hyperinsulinemic-euglycemic clamping which may reflect diurnal rhythmicity. Notwithstanding, there was no difference between levels of leptin in the hypoxic and the normoxic condition (P = .2). Since we did not find any significant changes in leptin responses upon hypoxia, plasma leptin levels do not seem to be affected by short hypoxic episodes of moderate degree.
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Affiliation(s)
- Andre Schmoller
- Department of Psychiatry and Psychotherapy, University of Luebeck, D-23538 Luebeck, Germany
| | - Michaela Voss
- Department of Psychiatry and Psychotherapy, University of Luebeck, D-23538 Luebeck, Germany
| | - Hartmut Gehring
- Department of Anaesthesiology, University of Luebeck, D-23538 Luebeck, Germany
| | - Sebastian Rudolf
- Department of Psychiatry and Psychotherapy, University of Luebeck, D-23538 Luebeck, Germany
| | - Ulrich Schweiger
- Department of Psychiatry and Psychotherapy, University of Luebeck, D-23538 Luebeck, Germany
| | - Bernd Schultes
- Interdisciplinary Obesity Center, St. Gallen, CH-9400 Rorschach, Switzerland
| | - Kerstin M. Oltmanns
- Department of Psychiatry and Psychotherapy, University of Luebeck, D-23538 Luebeck, Germany
- Department of Neuroendocrinology, University of Luebeck, D-23538 Luebeck, Germany
- *Kerstin M. Oltmanns:
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Sierra-Johnson J, Romero-Corral A, Somers VK, Johnson BD. Effect of altitude on leptin levels, does it go up or down? J Appl Physiol (1985) 2008; 105:1684-5. [PMID: 18276896 DOI: 10.1152/japplphysiol.01284.2007] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Affiliation(s)
- Justo Sierra-Johnson
- Division of Cardiovascular Diseases, Department of Internal Medicine, Mayo Clinic, Rochester, Minnesota 55905, USA
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Redolfi S, Corda L, La Piana G, Spandrio S, Prometti P, Tantucci C. Long-term non-invasive ventilation increases chemosensitivity and leptin in obesity-hypoventilation syndrome. Respir Med 2006; 101:1191-5. [PMID: 17189682 DOI: 10.1016/j.rmed.2006.11.005] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2006] [Revised: 11/07/2006] [Accepted: 11/09/2006] [Indexed: 12/22/2022]
Abstract
BACKGROUND Long-term nocturnal non-invasive mechanical ventilation (NIMV) is an effective treatment for obesity-hypoventilation syndrome (OHS), improving central carbon dioxide (CO(2)) sensitivity. Leptin might contribute to sustain adequate ventilation in obesity. The aim of the study was to investigate the role of leptin in the OHS pathogenesis looking at its relationship to CO(2) sensitivity before and after NIMV in OHS patients. METHODS In six obese patients (3F/3M; aged 63+/-9 yr; BMI 47.0+/-4.5 kg/m(2)) with OHS and without obstructive sleep apnoea-hypopnoea (OSAH) diurnal arterial blood gases, fasting plasma leptin concentration and CO(2) chemosensitivity were determined before and after 10.3+/-5.6 (range 6-20) months of NIMV. RESULTS After NIMV improvements were observed in gas exchange (PaO(2) from 51.3+/-6.7 to 75.0+/-10.3 mmHg, p<0.01; PaCO(2) from 55.5+/-4.8 to 43.7+/-1.2 mmHg, p<0.01; [HCO(3)(-)] from 33.3+/-3.8 to 29.8+/-1.7 mmol/l, p<0.05) and CO(2) chemosensitivity, measured as P(0.1)/PetCO(2) slope (from 0.09+/-0.07 to 0.18+/-0.07 cmH(2)O/mmHg, p<0.05) and V(E)/PetCO(2) slope (from 0.4+/-0.3 to 0.9+/-0.5l/min/mmHg, p=0.07). Plasma leptin increased from 34.5+/-21.1 ng/ml to 50.2+/-22.9 ng/ml (p<0.01) after NIMV and changes of the P(0.1)/PetCO(2) slope correlated with percent changes of plasma leptin (r(2)=0.79, p<0.05). CONCLUSIONS These findings suggest a possible role of leptin in the recovery of neuromuscular response to hypercapnia obtained during long-term nocturnal NIMV in OHS patients without OSAH.
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Affiliation(s)
- Stefania Redolfi
- Respiratory Medicine Unit, University of Brescia, Piazzale Spedali Civili 1, 25100 Brescia, Italy
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Barnholt KE, Hoffman AR, Rock PB, Muza SR, Fulco CS, Braun B, Holloway L, Mazzeo RS, Cymerman A, Friedlander AL. Endocrine responses to acute and chronic high-altitude exposure (4,300 meters): modulating effects of caloric restriction. Am J Physiol Endocrinol Metab 2006; 290:E1078-88. [PMID: 16380390 DOI: 10.1152/ajpendo.00449.2005] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
High-altitude anorexia leads to a hormonal response pattern modulated by both hypoxia and caloric restriction (CR). The purpose of this study was to compare altitude-induced neuroendocrine changes with or without energy imbalance and to explore how energy sufficiency alters the endocrine acclimatization process. Twenty-six normal-weight, young men were studied for 3 wk. One group [hypocaloric group (HYPO), n = 9] stayed at sea level and consumed 40% fewer calories than required to maintain body weight. Two other groups were deployed to 4,300 meters (Pikes Peak, CO), where one group (ADQ, n = 7) was adequately fed to maintain body weight and the other [deficient group (DEF), n = 10] had calories restricted as above. HYPO experienced a typical CR-induced reduction in many hormones such as insulin, testosterone, and leptin. At altitude, fasting glucose, insulin, and epinephrine exhibited a muted rise in DEF compared with ADQ. Free thyroxine, thyroid-stimulating hormone, and norepinephrine showed similar patterns between the two altitude groups. Morning cortisol initially rose higher in DEF than ADQ at 4,300 meters, but the difference disappeared by day 5. Testosterone increased in both altitude groups acutely but declined over time in DEF only. Adiponectin and leptin did not change significantly from sea level baseline values in either altitude group regardless of energy intake. These data suggest that hypoxia tends to increase blood hormone concentrations, but anorexia suppresses elements of the endocrine response. Such suppression results in the preservation of energy stores but may sacrifice the facilitation of oxygen delivery and the use of oxygen-efficient fuels.
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Affiliation(s)
- Kimberly E Barnholt
- Clinical Studies Unit, VA Palo Alto Health Care System, 3801 Miranda Ave., Palo Alto, CA 94304, USA
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Vats P, Singh SN, Singh VK, Shyam R, Upadhyay TN, Singh SB, Banerjee PK. Appetite regulatory peptides in Indian Antarctic expeditioners. Nutr Neurosci 2006; 8:233-8. [PMID: 16491648 DOI: 10.1080/10284150500193726] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Antarctica presents an inhospitable environment due to extreme low temperature, high wind velocity, low humidity, snowstorms, long polar days and nights, high level of UV radiations, magnetic storms and increased ionisation along with social isolation and sexual deprivation. Acclimatisation to any new condition is associated with certain metabolic changes along with alteration in nutritional requirements. There are reports of increased food intake and gain in body weight during past Indian Antarctic expeditions. Therefore, the present study was undertaken with the aim to assess the changes in appetite regulatory peptides i.e. leptin and neuropeptide Y in relation to energy intake and expenditure of the Antarctic expeditioners. The study was conducted in three phases viz. Phase I at Goa (basal), Phase II 48 h after reaching Antarctica and Phase III after one month of stay at Antarctica. Energy and nutrient intake were analysed from the duplicate plate samples of the expeditioners. Energy expenditure was computed using 24 h activity records for 7 days. Blood samples were collected in each phase for biochemical estimations. After reaching Antarctica, the expeditioners were active and the total energy expenditure (mean +/- SEM, n = 10) was found to be 3120 +/- 474 kcal/day. The actual energy intake was found to be 3911 +/- 310 kcal/day. This indicates that the Antarctic expeditioners had very active life and weight gain during expedition could be due to positive energy balance. After 48 h of stay at Antarctica plasma leptin levels (mean +/- SEM, n = 22) decreased from normal basal values 5.66 (+/- 0.59) ng/ml (Phase I) to 4.40 (+/- 0.37) ng/ml (Phase II), even though there was an increase in body fat. Increased level of plasma leptin was observed in Phase III as compared to phase I and II. Concomitantly there was increase in plasma neuropeptide Y levels from 0.303 (+/- 0.004) ng/ml to 1.211 (+/- 0. 27) ng/ml (p < 0.001) in Phase II and decrease in Phase III. The decrease in plasma leptin levels and increase in neuropeptide Y levels in Phase II may be responsible for increase in appetite and gain in body weight at Antarctica.
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Affiliation(s)
- Praveen Vats
- Defence Institute of Physiology and Allied Sciences, Lucknow Road, Timarpur, Delhi-110 054, India.
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Simler N, Grosfeld A, Peinnequin A, Guerre-Millo M, Bigard AX. Leptin receptor-deficient obese Zucker rats reduce their food intake in response to hypobaric hypoxia. Am J Physiol Endocrinol Metab 2006; 290:E591-7. [PMID: 16234269 DOI: 10.1152/ajpendo.00289.2005] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Exposure to hypoxia induces anorexia in humans and rodents, but the role of leptin remains under discussion and that of orexigenic and anorexigenic hypothalamic neuropeptides remains unknown. The present study was designed to address this issue by using obese (Lepr(fa)/Lepr(fa)) Zucker rats, a rat model of genetic leptin receptor deficiency. Homozygous lean (Lepr(FA)/Lepr(FA)) and obese (Lepr(fa)/Lepr(fa)) rats were randomly assigned to two groups, either kept at ambient pressure or exposed to hypobaric hypoxia for 1, 2, or 4 days (barometric pressure, 505 hPa). Food intake and body weight were recorded throughout the experiment. The expression of leptin and vascular endothelial growth factor (VEGF) genes was studied in adipose tissue with real-time quantitative PCR and that of selected orexigenic and anorexigenic neuropeptides was measured in the hypothalamus. Lean and obese rats exhibited a similar hypophagia (38 and 67% of initial values at day 1, respectively, P < 0.01) and initial decrease in body weight during hypoxia exposure. Hypoxia led to increased plasma leptin levels only in obese rats. This resulted from increased leptin gene expression in adipose tissue in response to hypoxia, in association with enhanced VEGF gene expression. Increased hypothalamic neuropeptide Y levels in lean rats 2 days after hypoxia exposure contributed to accounting for the enhanced food consumption. No significant changes occurred in the expression of other hypothalamic neuropeptides involved in the control of food intake. This study demonstrates unequivocally that altitude-induced anorexia cannot be ascribed to anorectic signals triggered by enhanced leptin production or alterations of hypothalamic neuropeptides involved in anabolic or catabolic pathways.
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Affiliation(s)
- Nadine Simler
- Department of Human Factors, Centre de Recherches du Service de Sante des Armees, La Tronche, Paris, France
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36
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Affiliation(s)
- Patricia L Brubaker
- Department of Physiology, Room 3366 Medical Sciences Bldg., University of Toronto, 1 King's College Circle, Toronto, ON, M5S 1A8, Canada.
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Tiollier E, Schmitt L, Burnat P, Fouillot JP, Robach P, Filaire E, Guezennec C, Richalet JP. Living high-training low altitude training: effects on mucosal immunity. Eur J Appl Physiol 2005; 94:298-304. [PMID: 15765238 DOI: 10.1007/s00421-005-1317-4] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2004] [Accepted: 12/27/2004] [Indexed: 10/25/2022]
Abstract
Secretory immunoglobulin A (sIgA) is the major immunoglobulin of the mucosal immune system. Whereas the suppressive effect of heavy training on mucosal immunity is well documented, little is known regarding the influence of hypoxia exposure on sIgA during altitude training. This investigation examined the impact of an 18-day Living high-training low (LHTL) training camp on sIgA levels in 11 (six females and five males) elite cross-country skiers. Subjects from the control group (n=5) trained and lived at 1,200 m of altitude, whereas, subjects from the LHTL group (n=6) trained at 1,200 m, but lived at a simulated altitude of 2,500, 3,000 and 3,500 m (3x6-day, 11 h day(-1)) in hypoxic rooms. Saliva samples were collected before, after each 6-day phases and 2 weeks thereafter (POST). Salivary sIgA, protein and cortisol were measured. There was a downward trend in sIgA concentrations over the study, which reached significance in LHTL (P<0.01), but not in control (P=0.08). Salivary IgA concentrations were still lower baseline at POST (P<0.05). Protein concentration increased in LHTL (P<0.05) and was negatively correlated with sIgA concentration after the 3,000 and 3,500 m-phase and at POST (P<0.05 all). Cortisol concentrations were unchanged over the study and no relationship was found between cortisol and sIgA. In summary, data were strongly suggestive of a cumulative negative effect of physical exercise and hypoxia on sIgA levels during LHTL training. Two weeks of active recovery did not allow for proper sIgA recovery. The mechanism underlying this depression of sIgA could be mediated by neural factors.
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Affiliation(s)
- E Tiollier
- Département de physiologie, IMASSA, 91223 Brétigny-sur-Orge Cedex, France.
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Gonzales GF, Chung FA, Miranda S, Valdez LB, Zaobornyj T, Bustamante J, Boveris A. Heart mitochondrial nitric oxide synthase is upregulated in male rats exposed to high altitude (4,340 m). Am J Physiol Heart Circ Physiol 2005; 288:H2568-73. [PMID: 15695556 DOI: 10.1152/ajpheart.00812.2004] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Male rats exposed for 21 days to high altitude (4,340 m) responded with arrest of weight gain and increased hematocrit and testosterone levels. High altitude significantly (58%) increased heart mitochondrial nitric oxide (NO) synthase (mtNOS) activity, whereas heart cytosolic endothelial NOS (eNOS) and liver mtNOS were not affected. Western blot analysis found heart mitochondria reacting only with anti-inducible NOS (iNOS) antibodies, whereas the postmitochondrial fraction reacted with anti-iNOS and anti-eNOS antibodies. In vitro-measured NOS activities allowed the estimation of cardiomyocyte capacity for NO production, a value that increased from 57% (sea level) to 79 nmol NO.min(-1).g heart(-1) (4,340 m). The contribution of mtNOS to total cell NO production increased from 62% (sea level) to 71% (4340 m). Heart mtNOS activity showed a linear relationship with hematocrit and a biphasic quadratic association with estradiol and testosterone. Multivariate analysis showed that exposure to high altitude linearly associates with hematocrit and heart mtNOS activity, and that testosterone-to-estradiol ratio and heart weight were not linearly associated with mtNOS activity. We conclude that high altitude triggers a physiological adaptive response that upregulates heart mtNOS activity and is associated in an opposed manner with the serum levels of testosterone and estradiol.
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Affiliation(s)
- Gustavo F Gonzales
- Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Junín 956, C1113AAD, Buenos Aires, Argentina
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39
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Severinghaus JW. Sightings. High Alt Med Biol 2004. [DOI: 10.1089/ham.2004.5.389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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