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Liu D, Gao X, Huang X, Fan Y, Wang YE, Zhang Y, Chen X, Wen J, He H, Hong Y, Liang Y, Zhang Y, Liu Z, Chen S, Li X. Moderate altitude exposure impacts host fasting blood glucose and serum metabolome by regulation of the intestinal flora. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 905:167016. [PMID: 37714338 DOI: 10.1016/j.scitotenv.2023.167016] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 09/09/2023] [Accepted: 09/10/2023] [Indexed: 09/17/2023]
Abstract
Moderate altitude exposure has shown beneficial effects on diabetes incidence but the underlying mechanisms are not understood. Our study aimed to investigate how the human gut microbiome impacted the serum metabolome and associated with glucose homeostasis in healthy Chinese individuals upon moderate-altitude exposure. Faecal microbiome composition was assessed using shotgun metagenomic sequencing. Serum metabolome was acquired by untargeted metabolomics technology, and amino acids (AAs) and propionic acid in serum were quantified by targeted metabolomics technology. The results indicated that the moderate-altitude exposed individuals presented lowered fasting blood glucose (FBG) and propionic acid, increased circulating L-Glutamine but decreased L-Glutamate and L-Valine, which correlated with enriched Bacteroidetes and decreased Proteobacteria. Additionally, the silico causality associations among gut microbiota, serum metabolome and host FBG were analyzed by mediation analysis. It showed that increased Bacteroides ovatus (B. ovatus) and decreased Escherichia coli (E. coli) were identified as the main antagonistic species driving the association between L-Glutamate and FBG in silico causality. Furthermore, the high-fat diet (HFD) fed mice subjected to faecal microbiota transplantation (FMT) were applied to validate the cause-in-fact effects of gut microbiota on the beneficial glucose response. We found that microbiome in the moderate-altitude exposed donor could predict the extent of the FBG response in recipient mice, which showed lowered FBG, L-Glutamate and Firmicutes/Bacteroidetes ratio. Our findings suggest that moderate-altitude exposure targeting gut microbiota and circulating metabolome, may pave novel avenues to counter dysglycemia.
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Affiliation(s)
- Dan Liu
- Department of Emergency Medicine, Guangdong Provincial People's Hospital, (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, China; Department of Endocrinology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China; Nyingchi People's Hospital, Tibet, China
| | - Xiaoyan Gao
- Department of Emergency Medicine, Guangdong Provincial People's Hospital, (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, China; School of Medicine, South China University of Technology, Guangzhou, China
| | - Xiaoran Huang
- Department of Emergency Medicine, Guangdong Provincial People's Hospital, (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, China
| | - Yanqun Fan
- Biotree Metabolomics Technology Research Center, Shanghai, China
| | - Yu-E Wang
- Nyingchi People's Hospital, Tibet, China
| | - Yuelin Zhang
- Department of Emergency Medicine, Guangdong Provincial People's Hospital, (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, China
| | - Xuanfu Chen
- Department of Emergency Medicine, Guangdong Provincial People's Hospital, (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, China; Emergency Medicine Department of Guangdong Cardiovascular Institute, Guangzhou, China
| | - Jielu Wen
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Guangdong-Hong Kong Joint Laboratory for RNA Medicine, Medical Research Center, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China; Nanhai Translational Innovation Center of Precision Immunology, Sun Yat-Sen Memorial Hospital, Foshan, China
| | - Haiwei He
- Department of Emergency Medicine, Guangdong Provincial People's Hospital, (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, China
| | - Yimei Hong
- Department of Emergency Medicine, Guangdong Provincial People's Hospital, (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, China
| | - Ying Liang
- Department of Emergency Medicine, Guangdong Provincial People's Hospital, (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, China; Department of Endocrinology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China; Nyingchi People's Hospital, Tibet, China
| | - Yuxiao Zhang
- Department of Emergency Medicine, Guangdong Provincial People's Hospital, (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, China; School of Medicine, South China University of Technology, Guangzhou, China
| | - Zhipeng Liu
- Biotree Metabolomics Technology Research Center, Shanghai, China.
| | - Sifan Chen
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Guangdong-Hong Kong Joint Laboratory for RNA Medicine, Medical Research Center, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, China; Nanhai Translational Innovation Center of Precision Immunology, Sun Yat-Sen Memorial Hospital, Foshan, China.
| | - Xin Li
- Department of Emergency Medicine, Guangdong Provincial People's Hospital, (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou, China; Nyingchi People's Hospital, Tibet, China.
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Nishimura T, Motoi M, Toyoshima H, Kishida F, Shin S, Katsumura T, Nakayama K, Oota H, Higuchi S, Watanuki S, Maeda T. Endocrine, inflammatory and immune responses and individual differences in acute hypobaric hypoxia in lowlanders. Sci Rep 2023; 13:12659. [PMID: 37542110 PMCID: PMC10403528 DOI: 10.1038/s41598-023-39894-w] [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: 03/24/2023] [Accepted: 08/01/2023] [Indexed: 08/06/2023] Open
Abstract
When lowlanders are exposed to environments inducing hypobaric hypoxia (HH) such as high mountains, hemodynamic changes occur to maintain oxygen levels in the body. However, changes to other physiological functions under such conditions have yet to be clarified. This study investigated changes in endocrine, inflammatory and immune parameters and individual differences during acute HH exposure using a climatic chamber (75 min of exposure to conditions mimicking 3500 m) in healthy lowlanders. Aldosterone and cortisol were significantly decreased and interleukin (IL)-6, IL-8 and white blood cell (WBC) counts were significantly increased after HH. Lower peripheral oxygen saturation (SpO2) was associated with higher IL-6 and WBC counts, and higher IL-8 was associated with higher cortisol. These findings suggest that endocrine, inflammatory and immune responses are evoked even with a short 75-min exposure to HH and individuals with lower SpO2 seemed to show more pronounced responses. Our results provide basic data for understanding the physiological responses and interactions of homeostatic systems during acute HH.
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Affiliation(s)
- Takayuki Nishimura
- Department of Human Life Design and Science, Faculty of Design, Kyushu University, 4-9-1 Shiobaru, Minami-Ku, Fukuoka, 815-8540, Japan.
| | - Midori Motoi
- Department of Living Business, Seika Women's Junior College, 2-12-1 Minamihachiman, Hakata-Ku, Fukuoka, 812-0886, Japan
| | - Hideo Toyoshima
- Fukuoka Urasoe Clinic, BCC Building 9F, 2-12-19 Ropponmatsu, Cyuou-Ku, Fukuoka, 810-0044, Japan
| | - Fumi Kishida
- Department of Medical Laboratory Science, Faculty of Health Sciences, Junshin Gakuen University, 1-1-1 Chikushigaoka, Minami-ku, Fukuoka, 815-8510, Japan
| | - Sora Shin
- Advanced Testing and Evaluation Center, FITI Testing & Research Institute, 79 Magokjungang 8-ro 3-Gil, Gangseo-gu, Seoul, 07791, South Korea
| | - Takafumi Katsumura
- Department of Anatomy, Kitasato University School of Medicine, 1-15-1 Kitazato, Minami-ku, Sagamihara, Kanagawa, 252-0374, Japan
| | - Kazuhiro Nakayama
- Department of Integrated Biosciences, The University of Tokyo, 5-1-5 Kashiwano-ha, Kashiwa-shi, Chiba, 277-8562, Japan
| | - Hiroki Oota
- Department of Biological Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Shigekazu Higuchi
- Department of Human Life Design and Science, Faculty of Design, Kyushu University, 4-9-1 Shiobaru, Minami-Ku, Fukuoka, 815-8540, Japan
| | - Shigeki Watanuki
- Department of Human Life Design and Science, Faculty of Design, Kyushu University, 4-9-1 Shiobaru, Minami-Ku, Fukuoka, 815-8540, Japan
| | - Takafumi Maeda
- Department of Human Life Design and Science, Faculty of Design, Kyushu University, 4-9-1 Shiobaru, Minami-Ku, Fukuoka, 815-8540, Japan
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Early Blood Glucose Level Post-Admission Correlates with the Outcomes and Oxidative Stress in Neonatal Hypoxic-Ischemic Encephalopathy. Antioxidants (Basel) 2021; 11:antiox11010039. [PMID: 35052543 PMCID: PMC8773159 DOI: 10.3390/antiox11010039] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Revised: 12/19/2021] [Accepted: 12/23/2021] [Indexed: 12/25/2022] Open
Abstract
The antioxidant defense system is involved in the pathogenesis of neonatal hypoxic-ischemic encephalopathy (HIE). To analyze the relationship between first serum blood glucose levels and outcomes in neonatal HIE, seventy-four patients were divided, based on the first glucose level, into group 1 (>0 mg/dL and <60 mg/dL, n =11), group 2 (≥60 mg/dL and <150 mg/dL, n = 49), and group 3 (≥150 mg/dL, n = 14). Abnormal glucose levels had poor outcomes among three groups in terms of the clinical stage (p = 0.001), brain parenchymal lesion (p = 0.004), and neurodevelopmental outcomes (p = 0.029). Hearing impairment was more common in group 3 than in group 1 (p = 0.062) and group 2 (p = 0.010). The MRI findings of group 3 exhibited more thalamus and basal ganglion lesions than those of group 1 (p = 0.012). The glucose level was significantly correlated with clinical staging (p< 0.001), parenchymal brain lesions (p = 0.044), hearing impairment (p = 0.003), and neurodevelopmental outcomes (p = 0.005) by Pearson’s test. The first blood glucose level in neonatal HIE is an important biomarker for clinical staging, MRI findings, as well as hearing and neurodevelopment outcomes. Hyperglycemic patients had a higher odds ratio for thalamus, basal ganglia, and brain stem lesions than hypoglycemic patients with white matter and focal ischemic injury. Hyperglycemia can be due to prolonged or intermittent hypoxia and can be associated with poor outcomes.
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Tenorio-Lopes L, Kinkead R. Sex-Specific Effects of Stress on Respiratory Control: Plasticity, Adaptation, and Dysfunction. Compr Physiol 2021; 11:2097-2134. [PMID: 34107062 DOI: 10.1002/cphy.c200022] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
As our understanding of respiratory control evolves, we appreciate how the basic neurobiological principles of plasticity discovered in other systems shape the development and function of the respiratory control system. While breathing is a robust homeostatic function, there is growing evidence that stress disrupts respiratory control in ways that predispose to disease. Neonatal stress (in the form of maternal separation) affects "classical" respiratory control structures such as the peripheral O2 sensors (carotid bodies) and the medulla (e.g., nucleus of the solitary tract). Furthermore, early life stress disrupts the paraventricular nucleus of the hypothalamus (PVH), a structure that has emerged as a primary determinant of the intensity of the ventilatory response to hypoxia. Although underestimated, the PVH's influence on respiratory function is a logical extension of the hypothalamic control of metabolic demand and supply. In this article, we review the functional and anatomical links between the stress neuroendocrine axis and the medullary network regulating breathing. We then present the persistent and sex-specific effects of neonatal stress on respiratory control in adult rats. The similarities between the respiratory phenotype of stressed rats and clinical manifestations of respiratory control disorders such as sleep-disordered breathing and panic attacks are remarkable. These observations are in line with the scientific consensus that the origins of adult disease are often found among developmental and biological disruptions occurring during early life. These observations bring a different perspective on the structural hierarchy of respiratory homeostasis and point to new directions in our understanding of the etiology of respiratory control disorders. © 2021 American Physiological Society. Compr Physiol 11:1-38, 2021.
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Affiliation(s)
- Luana Tenorio-Lopes
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, The University of Calgary, Calgary, Alberta, Canada
| | - Richard Kinkead
- Département de Pédiatrie, Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Quebec City, Quebec, Canada
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Exploring the Mediators that Promote Carotid Body Dysfunction in Type 2 Diabetes and Obesity Related Syndromes. Int J Mol Sci 2020; 21:ijms21155545. [PMID: 32756352 PMCID: PMC7432672 DOI: 10.3390/ijms21155545] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 07/26/2020] [Accepted: 07/30/2020] [Indexed: 12/12/2022] Open
Abstract
Carotid bodies (CBs) are peripheral chemoreceptors that sense changes in blood O2, CO2, and pH levels. Apart from ventilatory control, these organs are deeply involved in the homeostatic regulation of carbohydrates and lipid metabolism and inflammation. It has been described that CB dysfunction is involved in the genesis of metabolic diseases and that CB overactivation is present in animal models of metabolic disease and in prediabetes patients. Additionally, resection of the CB-sensitive nerve, the carotid sinus nerve (CSN), or CB ablation in animals prevents and reverses diet-induced insulin resistance and glucose intolerance as well as sympathoadrenal overactivity, meaning that the beneficial effects of decreasing CB activity on glucose homeostasis are modulated by target-related efferent sympathetic nerves, through a reflex initiated in the CBs. In agreement with our pre-clinical data, hyperbaric oxygen therapy, which reduces CB activity, improves glucose homeostasis in type 2 diabetes patients. Insulin, leptin, and pro-inflammatory cytokines activate the CB. In this manuscript, we review in a concise manner the putative pathways linking CB chemoreceptor deregulation with the pathogenesis of metabolic diseases and discuss and present new data that highlight the roles of hyperinsulinemia, hyperleptinemia, and chronic inflammation as major factors contributing to CB dysfunction in metabolic disorders.
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Michalek-Zrabkowska M, Wieckiewicz M, Smardz J, Gac P, Poreba R, Wojakowska A, Mazur G, Martynowicz H. Determination of Inflammatory Markers, Hormonal Disturbances, and Sleepiness Associated with Sleep Bruxism Among Adults. Nat Sci Sleep 2020; 12:969-979. [PMID: 33204200 PMCID: PMC7667147 DOI: 10.2147/nss.s268470] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Accepted: 09/14/2020] [Indexed: 12/15/2022] Open
Abstract
PURPOSE Sleep bruxism (SB) is characterized by repetitive phasic, tonic, or mixed masticatory muscle activity during sleep with multifactorial etiology. Previous studies have shown that the complex origin of SB can be related to the psychological features of the affected individual, consumption of caffeine and alcohol, smoking, obstructive sleep apnea, diabetes, increased body mass index, hypertension, thyroid diseases, and probable genetic vulnerability. This study aimed to investigate the inflammatory markers, hormonal disturbances, and sleepiness associated with SB, which have a potential effect on the total cardiovascular (CV) risk among relatively young and healthy patients. PATIENTS AND METHODS A total of 74 individuals with probable SB were subjected to single-night polysomnography, followed by blood panel and 24-h urinary excretion tests. The level of daytime sleepiness was assessed in the participants using the Epworth Sleepiness Scale. RESULTS SB was found in 78.4% of participants. The bruxism episode index (BEI) positively correlated with the concentrations of 17-hydroxycorticosteroids, C-reactive protein, and fibrinogen in the collected urine samples. A positive correlation was also found between phasic BEI and glucose concentration 2 h after the consumption of glucose solution. Sleep bruxers showed significantly increased sleepiness compared to nonbruxers (p = 0.02). The scores on sleepiness were positively correlated with mixed BEI, minimal oxygen saturation, and mean heart rate. CONCLUSION The results of this study revealed that participants with SB had metabolic and hormonal disturbances, probably due to stress and sympathetic activity. Moreover, it was found that young sleep bruxers potentially have a high CV risk due to the increased level of inflammatory and stress markers.
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Affiliation(s)
- Monika Michalek-Zrabkowska
- Department of Internal Medicine, Occupational Diseases, Hypertension and Clinical Oncology, Wroclaw Medical University, Wroclaw 50-556, Poland
| | - Mieszko Wieckiewicz
- Department of Experimental Dentistry, Wroclaw Medical University, Wroclaw 50-425, Poland
| | - Joanna Smardz
- Department of Experimental Dentistry, Wroclaw Medical University, Wroclaw 50-425, Poland
| | - Pawel Gac
- Department of Hygiene, Wroclaw Medical University, Wroclaw 50-345, Poland
| | - Rafal Poreba
- Department of Internal Medicine, Occupational Diseases, Hypertension and Clinical Oncology, Wroclaw Medical University, Wroclaw 50-556, Poland
| | - Anna Wojakowska
- Department of Internal Medicine, Occupational Diseases, Hypertension and Clinical Oncology, Wroclaw Medical University, Wroclaw 50-556, Poland
| | - Grzegorz Mazur
- Department of Internal Medicine, Occupational Diseases, Hypertension and Clinical Oncology, Wroclaw Medical University, Wroclaw 50-556, Poland
| | - Helena Martynowicz
- Department of Internal Medicine, Occupational Diseases, Hypertension and Clinical Oncology, Wroclaw Medical University, Wroclaw 50-556, Poland
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Estoppey J, Léger B, Vuistiner P, Sartori C, Kayser B. Low- and High-Altitude Cortisol Awakening Responses Differ Between AMS-Prone and AMS-Resistant Mountaineers. High Alt Med Biol 2019; 20:344-351. [DOI: 10.1089/ham.2019.0035] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Affiliation(s)
- Jan Estoppey
- Institute of Sport Sciences, Synathlon, Uni-Centre, Lausanne, Switzerland
| | - Bertrand Léger
- Department of Medical Research, Romandie Clinic for Rehabilitation, Sion, Switzerland
| | - Philippe Vuistiner
- Department of Medical Research, Romandie Clinic for Rehabilitation, Sion, Switzerland
| | - Claudio Sartori
- Department of Internal Medicine, University Hospital, Lausanne, Switzerland
| | - Bengt Kayser
- Institute of Sport Sciences, Synathlon, Uni-Centre, Lausanne, Switzerland
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Gatterer H, Bernatzky G, Burtscher J, Rainer M, Kayser B, Burtscher M. Are Pre-Ascent Low-Altitude Saliva Cortisol Levels Related to the Subsequent Acute Mountain Sickness Score? Observations from a Field Study. High Alt Med Biol 2019; 20:337-343. [DOI: 10.1089/ham.2019.0034] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Affiliation(s)
- Hannes Gatterer
- Institute of Mountain Emergency Medicine, Eurac Research, Bolzano, Italy
- Department of Sport Science, University of Innsbruck, Innsbruck, Austria
| | - Günther Bernatzky
- Department of Ecology and Evolution, University of Salzburg, Salzburg, Austria
| | - Johannes Burtscher
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | | | - Bengt Kayser
- Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland
| | - Martin Burtscher
- Department of Sport Science, University of Innsbruck, Innsbruck, Austria
- Austrian Society for Alpine and Mountain Medicine, Austria
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Koufakis T, Karras SN, Mustafa OG, Zebekakis P, Kotsa K. The Effects of High Altitude on Glucose Homeostasis, Metabolic Control, and Other Diabetes-Related Parameters: From Animal Studies to Real Life. High Alt Med Biol 2018; 20:1-11. [PMID: 30362832 DOI: 10.1089/ham.2018.0076] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Exposure to high altitude activates several complex and adaptive mechanisms aiming to protect human homeostasis from extreme environmental conditions, such as hypoxia and low temperatures. Short-term exposure is followed by transient hyperglycemia, mainly triggered by the activation of the sympathetic system, whereas long-term exposure results in lower plasma glucose concentrations, mediated by improved insulin sensitivity and augmented peripheral glucose disposal. An inverse relationship between altitude, diabetes, and obesity has been well documented. This is the result of genetic and physiological adaptations principally to hypoxia that favorably affect glucose metabolism; however, the contribution of financial, dietary, and other life-style parameters may also be important. According to existing evidence, people with diabetes are capable of undertaking demanding physical challenges even at extreme altitudes. Still, a number of issues should be taken into account, including the increased physical activity leading to changes in insulin demands and resistance, the performance of measurement systems under extreme weather conditions and the potential deterioration of metabolic control during climbing expeditions. The aim of this review is to present available evidence in the field in a comprehensive way, beginning from the physiology of glucose homeostasis adaptation mechanisms to high altitudes and ending to what real life experience has taught us.
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Affiliation(s)
- Theocharis Koufakis
- 1 Division of Endocrinology and Metabolism and Diabetes Center, First Department of Internal Medicine, Medical School, Aristotle University of Thessaloniki, AHEPA University Hospital , Thessaloniki, Greece
| | - Spyridon N Karras
- 1 Division of Endocrinology and Metabolism and Diabetes Center, First Department of Internal Medicine, Medical School, Aristotle University of Thessaloniki, AHEPA University Hospital , Thessaloniki, Greece
| | - Omar G Mustafa
- 2 Department of Diabetes, King's College Hospital , London, United Kingdom
| | - Pantelis Zebekakis
- 1 Division of Endocrinology and Metabolism and Diabetes Center, First Department of Internal Medicine, Medical School, Aristotle University of Thessaloniki, AHEPA University Hospital , Thessaloniki, Greece
| | - Kalliopi Kotsa
- 1 Division of Endocrinology and Metabolism and Diabetes Center, First Department of Internal Medicine, Medical School, Aristotle University of Thessaloniki, AHEPA University Hospital , Thessaloniki, Greece
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Abu Eid S, Hackl MT, Kaplanian M, Winter MP, Kaltenecker D, Moriggl R, Luger A, Scherer T, Fürnsinn C. Life Under Hypoxia Lowers Blood Glucose Independently of Effects on Appetite and Body Weight in Mice. Front Endocrinol (Lausanne) 2018; 9:490. [PMID: 30210452 PMCID: PMC6121030 DOI: 10.3389/fendo.2018.00490] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Accepted: 08/06/2018] [Indexed: 11/13/2022] Open
Abstract
Blood glucose and the prevalence of diabetes are lower in mountain than lowland dwellers, which could among other factors be due to reduced oxygen availability. To investigate metabolic adaptations to life under hypoxia, male mice on high fat diet (HFD) were continuously maintained at 10% O2. At variance to preceding studies, the protocol was designed to dissect direct metabolic effects from such mediated indirectly via hypoxia-induced reductions in appetite and weight gain. This was achieved by two separate control groups on normal air, one with free access to HFD, and one fed restrictedly in order to obtain a weight curve matching that of hypoxia-exposed mice. Comparable body weight in restrictedly fed and hypoxic mice was achieved by similar reductions in calorie intake (-22%) and was associated with parallel effects on body composition as well as on circulating insulin, leptin, FGF-21, and adiponectin. Whereas the effects of hypoxia on the above parameters could thus be attributed entirely to blunted weight gain, hypoxia improved glucose homeostasis in part independently of body weight (fasted blood glucose, mmol/l: freely fed control, 10.2 ± 0.7; weight-matched control, 8.0 ± 0.3; hypoxia, 6.8 ± 0.2; p < 0.007 each; AUC in the glucose tolerance test, mol/l*min: freely fed control, 2.54 ± 0.15; weight-matched control, 1.86 ± 0.08; hypoxia, 1.67 ± 0.05; p < 0.05 each). Although counterintuitive to lowering of glycemia, insulin sensitivity appeared to be impaired in animals adapted to hypoxia: In the insulin tolerance test, hypoxia-treated mice started off with lower glycaemia than their weight-matched controls (initial blood glucose, mmol/l: freely fed control, 11.5 ± 0.7; weight-matched control, 9.4 ± 0.3; hypoxia, 8.1 ± 0.2; p < 0.02 each), but showed a weaker response to insulin (final blood glucose, mmol/l: freely fed control, 7.0 ± 0.3; weight-matched control, 4.5 ± 0.2; hypoxia, 5.5 ± 0.3; p < 0.01 each). Furthermore, hypoxia weight-independently reduced hepatic steatosis as normalized to total body fat, suggesting a shift in the relative distribution of triglycerides from liver to fat (mg/g liver triglycerides per g total fat mass: freely fed control, 10.3 ± 0.6; weight-matched control, 5.6 ± 0.3; hypoxia, 4.0 ± 0.2; p < 0.0004 each). The results show that exposure of HFD-fed mice to continuous hypoxia leads to a unique metabolic phenotype characterized by improved glucose homeostasis along with evidence for impaired rather than enhanced insulin sensitivity.
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Affiliation(s)
- Sameer Abu Eid
- Division of Endocrinology & Metabolism, Department of Medicine III, Medical University of Vienna, Vienna, Austria
| | - Martina T. Hackl
- Division of Endocrinology & Metabolism, Department of Medicine III, Medical University of Vienna, Vienna, Austria
| | - Mairam Kaplanian
- Division of Endocrinology & Metabolism, Department of Medicine III, Medical University of Vienna, Vienna, Austria
| | - Max-Paul Winter
- Division of Cardiology, Department of Medicine II, Medical University of Vienna, Vienna, Austria
| | - Doris Kaltenecker
- Institute of Animal Breeding and Genetics, University of Veterinary Medicine Vienna, Vienna, Austria
- Ludwig Boltzmann Institute for Cancer Research, Vienna, Austria
| | - Richard Moriggl
- Institute of Animal Breeding and Genetics, University of Veterinary Medicine Vienna, Vienna, Austria
- Ludwig Boltzmann Institute for Cancer Research, Vienna, Austria
- Medical University of Vienna, Vienna, Austria
| | - Anton Luger
- Division of Endocrinology & Metabolism, Department of Medicine III, Medical University of Vienna, Vienna, Austria
| | - Thomas Scherer
- Division of Endocrinology & Metabolism, Department of Medicine III, Medical University of Vienna, Vienna, Austria
| | - Clemens Fürnsinn
- Division of Endocrinology & Metabolism, Department of Medicine III, Medical University of Vienna, Vienna, Austria
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Aguilar R, Martínez C, Alvero-Cruz JR. Cortisol awakening response and emotion at extreme altitudes on Mount Kangchenjunga. Int J Psychophysiol 2017; 131:81-88. [PMID: 29278692 DOI: 10.1016/j.ijpsycho.2017.12.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Revised: 11/21/2017] [Accepted: 12/17/2017] [Indexed: 11/20/2022]
Abstract
The cortisol awakening response (CAR) was examined over a 45days stay at extreme altitudes (above of about 5500m) on Mount Kangchenjunga. The CAR refers to a peak cortisol response during the waking period that is superimposed to the diurnal rhythmicity in cortisol secretion, whose function has been proposed to be the anticipation of demands of the upcoming day (the CAR anticipation hypothesis). According to this hypothesis, we distinguished between resting days on which the expedition team engaged in routine activities in the base camp, and ascent days on which it planned to climb up a very demanding track. We were also interested in examining the association of testosterone with emotional anticipation, given the role of this steroid hormone in reward-related processes in challenge situations. Results showed that the climber group had a bigger CAR on ascent days, relative to the Sherpa group at the same altitude and the non-climber group at sea level. Several methodological issues, however, made it difficult to interpret these group differences in terms of the CAR anticipation hypothesis (e.g. a seemingly influential covariate was awakening time). Although based on tentative results, correlational and regression analyses controlling for awakening time coherently showed that the CAR was associated with anticipation of a hard day and feelings of fear, and testosterone was associated with feelings of energy and positive affect. Whether or not the anticipation of a hard day played a key role in regulation of the CAR, the observation of an intact CAR in the climber group under hypobaric hypoxia conditions would require in-depth reflection from the perspective of human adaptive evolution.
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Affiliation(s)
- Raúl Aguilar
- Facultad de Psicología, Universidad de Málaga, Campus Teatinos s/n, 29071 Málaga, Spain.
| | - Carlos Martínez
- Facultad de Medicina, Universidad de Málaga, Campus Teatinos s/n, 29071 Málaga, Spain
| | - José R Alvero-Cruz
- Facultad de Medicina, Universidad de Málaga, Campus Teatinos s/n, 29071 Málaga, Spain
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Wandrag L, Siervo M, Riley HL, Khosravi M, Fernandez BO, Leckstrom CA, Martin DS, Mitchell K, Levett DZH, Montgomery HE, Mythen MG, Stroud MA, Grocott MPW, Feelisch M. Does hypoxia play a role in the development of sarcopenia in humans? Mechanistic insights from the Caudwell Xtreme Everest Expedition. Redox Biol 2017; 13:60-68. [PMID: 28570949 PMCID: PMC5451185 DOI: 10.1016/j.redox.2017.05.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Revised: 04/25/2017] [Accepted: 05/05/2017] [Indexed: 12/24/2022] Open
Abstract
Objectives Sarcopenia refers to the involuntary loss of skeletal muscle and is a predictor of physical disability/mortality. Its pathogenesis is poorly understood, although roles for altered hypoxic signaling, oxidative stress, adipokines and inflammatory mediators have been suggested. Sarcopenia also occurs upon exposure to the hypoxia of high altitude. Using data from the Caudwell Xtreme Everest expedition we therefore sought to analyze the extent of hypoxia-induced body composition changes and identify putative pathways associated with fat-free mass (FFM) and fat mass (FM) loss. Methods After baseline testing in London (75 m), 24 investigators ascended from Kathmandu (1300 m) to Everest base camp (EBC 5300 m) over 13 days. Fourteen investigators climbed above EBC, eight of whom reached the summit (8848 m). Assessments were conducted at baseline, during ascent and after one, six and eight week(s) of arrival at EBC. Changes in body composition (FM, FFM, total body water, intra- and extra-cellular water) were measured by bioelectrical impedance. Biomarkers of nitric oxide and oxidative stress were measured together with adipokines, inflammatory, metabolic and vascular markers. Results Participants lost a substantial, but variable, amount of body weight (7.3±4.9 kg by expedition end; p<0.001). A progressive loss of both FM and FFM was observed, and after eight weeks, the proportion of FFM loss was 48% greater than FM loss (p<0.008). Changes in protein carbonyls (p<0.001) were associated with a decline in FM whereas 4-hydroxynonenal (p<0.001) and IL-6 (p<0.001) correlated with FFM loss. GLP-1 (r=−0.45, p<0.001) and nitrite (r=−0.29, p<0.001) concentration changes were associated with FFM loss. In a multivariate model, GLP-1, insulin and nitrite were significant predictors of FFM loss while protein carbonyls were predicted FM loss. Conclusions The putative role of GLP-1 and nitrite as mediators of the effects of hypoxia on FFM is an intriguing finding. If confirmed, nutritional and pharmacological interventions targeting these pathways may offer new avenues for prevention and treatment of sarcopenia.
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Affiliation(s)
- Liesl Wandrag
- Nutrition and Dietetic Research Group, Department of Investigative Medicine, Imperial College London, UK; University College London Centre for Altitude Space and Extreme Environment Medicine, UCLH NIHR Biomedical Research Centre, Institute of Sport and Exercise Health, 170 Tottenham Court Road, London W1T 7HA, UK
| | - Mario Siervo
- Human Nutrition Research Centre, Institute of Cellular Medicine, Newcastle University, Campus for Ageing and Vitality, Newcastle on Tyne NE4 5PL, UK
| | - Heather L Riley
- Warwick Systems Biology Centre and Warwick Medical School, University of Warwick, Coventry CV4 7AL, UK
| | - Maryam Khosravi
- University College London Centre for Altitude Space and Extreme Environment Medicine, UCLH NIHR Biomedical Research Centre, Institute of Sport and Exercise Health, 170 Tottenham Court Road, London W1T 7HA, UK; Department of Cell and Developmental Biology, Division of Biosciences, University College London, WC1B 6BT, UK
| | - Bernadette O Fernandez
- Warwick Systems Biology Centre and Warwick Medical School, University of Warwick, Coventry CV4 7AL, UK; Clinical & Experimental Sciences, Faculty of Medicine, University of Southampton and University Hospital Southampton NHS Foundation Trust, Southampton SO16 6YD, UK
| | - Carl A Leckstrom
- Warwick Systems Biology Centre and Warwick Medical School, University of Warwick, Coventry CV4 7AL, UK
| | - Daniel S Martin
- University College London Centre for Altitude Space and Extreme Environment Medicine, UCLH NIHR Biomedical Research Centre, Institute of Sport and Exercise Health, 170 Tottenham Court Road, London W1T 7HA, UK; Division of Surgery and Interventional Science, University College London, 9th Floor, Royal Free Hospital, London NW3 2QG, UK
| | - Kay Mitchell
- University College London Centre for Altitude Space and Extreme Environment Medicine, UCLH NIHR Biomedical Research Centre, Institute of Sport and Exercise Health, 170 Tottenham Court Road, London W1T 7HA, UK; University Hospital Southampton NHS Foundation Trust, Southampton General Hospital, Southampton SO16 6YD, UK
| | - Denny Z H Levett
- University College London Centre for Altitude Space and Extreme Environment Medicine, UCLH NIHR Biomedical Research Centre, Institute of Sport and Exercise Health, 170 Tottenham Court Road, London W1T 7HA, UK; University Hospital Southampton NHS Foundation Trust, Southampton General Hospital, Southampton SO16 6YD, UK; Southampton NIHR Respiratory Biomedical Research Unit, UK
| | - Hugh E Montgomery
- University College London Centre for Altitude Space and Extreme Environment Medicine, UCLH NIHR Biomedical Research Centre, Institute of Sport and Exercise Health, 170 Tottenham Court Road, London W1T 7HA, UK
| | - Monty G Mythen
- University College London Centre for Altitude Space and Extreme Environment Medicine, UCLH NIHR Biomedical Research Centre, Institute of Sport and Exercise Health, 170 Tottenham Court Road, London W1T 7HA, UK
| | - Michael A Stroud
- University Hospital Southampton NHS Foundation Trust, Southampton General Hospital, Southampton SO16 6YD, UK
| | - Michael P W Grocott
- University College London Centre for Altitude Space and Extreme Environment Medicine, UCLH NIHR Biomedical Research Centre, Institute of Sport and Exercise Health, 170 Tottenham Court Road, London W1T 7HA, UK; Clinical & Experimental Sciences, Faculty of Medicine, University of Southampton and University Hospital Southampton NHS Foundation Trust, Southampton SO16 6YD, UK; University Hospital Southampton NHS Foundation Trust, Southampton General Hospital, Southampton SO16 6YD, UK; Southampton NIHR Respiratory Biomedical Research Unit, UK
| | - Martin Feelisch
- Warwick Systems Biology Centre and Warwick Medical School, University of Warwick, Coventry CV4 7AL, UK; Clinical & Experimental Sciences, Faculty of Medicine, University of Southampton and University Hospital Southampton NHS Foundation Trust, Southampton SO16 6YD, UK; University Hospital Southampton NHS Foundation Trust, Southampton General Hospital, Southampton SO16 6YD, UK; Southampton NIHR Respiratory Biomedical Research Unit, UK.
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Hocker AD, Stokes JA, Powell FL, Huxtable AG. The impact of inflammation on respiratory plasticity. Exp Neurol 2017; 287:243-253. [PMID: 27476100 PMCID: PMC5121034 DOI: 10.1016/j.expneurol.2016.07.022] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Revised: 07/22/2016] [Accepted: 07/26/2016] [Indexed: 02/08/2023]
Abstract
Breathing is a vital homeostatic behavior and must be precisely regulated throughout life. Clinical conditions commonly associated with inflammation, undermine respiratory function may involve plasticity in respiratory control circuits to compensate and maintain adequate ventilation. Alternatively, other clinical conditions may evoke maladaptive plasticity. Yet, we have only recently begun to understand the effects of inflammation on respiratory plasticity. Here, we review some of common models used to investigate the effects of inflammation and discuss the impact of inflammation on nociception, chemosensory plasticity, medullary respiratory centers, motor plasticity in motor neurons and respiratory frequency, and adaptation to high altitude. We provide new data suggesting glial cells contribute to CNS inflammatory gene expression after 24h of sustained hypoxia and inflammation induced by 8h of intermittent hypoxia inhibits long-term facilitation of respiratory frequency. We also discuss how inflammation can have opposite effects on the capacity for plasticity, whereby it is necessary for increases in the hypoxic ventilatory response with sustained hypoxia, but inhibits phrenic long term facilitation after intermittent hypoxia. This review highlights gaps in our knowledge about the effects of inflammation on respiratory control (development, age, and sex differences). In summary, data to date suggest plasticity can be either adaptive or maladaptive and understanding how inflammation alters the respiratory system is crucial for development of better therapeutic interventions to promote breathing and for utilization of plasticity as a clinical treatment.
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Affiliation(s)
- Austin D Hocker
- Department of Human Physiology, University of Oregon, Eugene, Oregon, United States
| | - Jennifer A Stokes
- Division of Physiology, Department of Medicine, University of California San Diego, La Jolla, California, United States
| | - Frank L Powell
- Division of Physiology, Department of Medicine, University of California San Diego, La Jolla, California, United States
| | - Adrianne G Huxtable
- Department of Human Physiology, University of Oregon, Eugene, Oregon, United States.
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Mackenzie RWA, Watt P. A Molecular and Whole Body Insight of the Mechanisms Surrounding Glucose Disposal and Insulin Resistance with Hypoxic Treatment in Skeletal Muscle. J Diabetes Res 2016; 2016:6934937. [PMID: 27274997 PMCID: PMC4871980 DOI: 10.1155/2016/6934937] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Revised: 04/04/2016] [Accepted: 04/12/2016] [Indexed: 12/22/2022] Open
Abstract
Although the mechanisms are largely unidentified, the chronic or intermittent hypoxic patterns occurring with respiratory diseases, such as chronic pulmonary disease or obstructive sleep apnea (OSA) and obesity, are commonly associated with glucose intolerance. Indeed, hypoxia has been widely implicated in the development of insulin resistance either via the direct action on insulin receptor substrate (IRS) and protein kinase B (PKB/Akt) or indirectly through adipose tissue expansion and systemic inflammation. Yet hypoxia is also known to encourage glucose transport using insulin-dependent mechanisms, largely reliant on the metabolic master switch, 5' AMP-activated protein kinase (AMPK). In addition, hypoxic exposure has been shown to improve glucose control in type 2 diabetics. The literature surrounding hypoxia-induced changes to glycemic control appears to be confusing and conflicting. How is it that the same stress can seemingly cause insulin resistance while increasing glucose uptake? There is little doubt that acute hypoxia increases glucose metabolism in skeletal muscle and does so using the same pathway as muscle contraction. The purpose of this review paper is to provide an insight into the mechanisms underpinning the observed effects and to open up discussions around the conflicting data surrounding hypoxia and glucose control.
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Affiliation(s)
- R. W. A. Mackenzie
- Department of Life Science, Whitelands College, University of Roehampton, Holybourne Avenue, London SW15 4DJ, UK
- *R. W. A. Mackenzie:
| | - P. Watt
- University of Brighton, Hillbrow, Denton Road, Eastbourne BN20 7SP, UK
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Jacobs RA, Lundby AKM, Fenk S, Gehrig S, Siebenmann C, Flück D, Kirk N, Hilty MP, Lundby C. Twenty-eight days of exposure to 3454 m increases mitochondrial volume density in human skeletal muscle. J Physiol 2015; 594:1151-66. [PMID: 26339730 DOI: 10.1113/jp271118] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Accepted: 08/28/2015] [Indexed: 12/11/2022] Open
Abstract
The role of hypoxia on skeletal muscle mitochondria is controversial. Studies superimposing exercise training on hypoxic exposure demonstrate an increase in skeletal muscle mitochondrial volume density (Mito(VD)) over equivalent normoxic training. In contrast, reductions in both skeletal muscle mass and Mito(VD) have been reported following mountaineering expeditions. These observations may, however, be confounded by negative energy balance, which may obscure the results. Accordingly we sought to examine the effects of high altitude hypoxic exposure on mitochondrial characteristics, with emphasis on Mito(VD), while minimizing changes in energy balance. For this purpose, skeletal muscle biopsies were obtained from nine lowlanders at sea level (Pre) and following 7 and 28 days of exposure to 3454 m. Maximal ergometer power output, whole body weight and composition, leg lean mass and skeletal muscle fibre area all remained unchanged following the altitude exposure. Transmission electron microscopy determined that intermyofibrillar (IMF) Mito(VD) was augmented (P = 0.028) by 11.5 ± 9.2% from Pre (5.05 ± 0.9%) to 28 Days (5.61 ± 0.04%). In contrast, there was no change in subsarcolemmal (SS) Mito(VD). As a result, total Mito(VD) (IMF + SS) was increased (P = 0.031) from 6.20 ± 1.5% at Pre to 6.62 ± 1.4% at 28 Days (7.8 ± 9.3%). At the same time no changes in mass-specific respiratory capacities, mitochondrial protein or antioxidant content were found. This study demonstrates that skeletal muscle Mito(VD) may increase with 28 days acclimation to 3454 m.
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Affiliation(s)
- Robert A Jacobs
- Zürich Centre for Integrative Human Physiology, Institute of Physiology, University of Zürich, Switzerland.,Health and Physical Education, School of Teaching and Learning, Western Carolina University, Cullowhee, NC, USA.,Physical Therapy Department, Western Carolina University, Cullowhee, NC, USA
| | | | - Simone Fenk
- Zürich Centre for Integrative Human Physiology, Institute of Physiology, University of Zürich, Switzerland
| | - Saskia Gehrig
- Zürich Centre for Integrative Human Physiology, Institute of Physiology, University of Zürich, Switzerland
| | - Christoph Siebenmann
- Zürich Centre for Integrative Human Physiology, Institute of Physiology, University of Zürich, Switzerland.,Department of Environmental Physiology, School of Technology and Health, Royal Institute of Technology, Solna, Sweden
| | - Daniela Flück
- Zürich Centre for Integrative Human Physiology, Institute of Physiology, University of Zürich, Switzerland
| | - Niels Kirk
- Zürich Centre for Integrative Human Physiology, Institute of Physiology, University of Zürich, Switzerland
| | | | - Carsten Lundby
- Zürich Centre for Integrative Human Physiology, Institute of Physiology, University of Zürich, Switzerland
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Woolcott OO, Ader M, Bergman RN. Glucose homeostasis during short-term and prolonged exposure to high altitudes. Endocr Rev 2015; 36:149-73. [PMID: 25675133 PMCID: PMC4399271 DOI: 10.1210/er.2014-1063] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Most of the literature related to high altitude medicine is devoted to the short-term effects of high-altitude exposure on human physiology. However, long-term effects of living at high altitudes may be more important in relation to human disease because more than 400 million people worldwide reside above 1500 m. Interestingly, individuals living at higher altitudes have a lower fasting glycemia and better glucose tolerance compared with those who live near sea level. There is also emerging evidence of the lower prevalence of both obesity and diabetes at higher altitudes. The mechanisms underlying improved glucose control at higher altitudes remain unclear. In this review, we present the most current evidence about glucose homeostasis in residents living above 1500 m and discuss possible mechanisms that could explain the lower fasting glycemia and lower prevalence of obesity and diabetes in this population. Understanding the mechanisms that regulate and maintain the lower fasting glycemia in individuals who live at higher altitudes could lead to new therapeutics for impaired glucose homeostasis.
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Affiliation(s)
- Orison O Woolcott
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, California 90048
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17
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Allam G, Alsulaimani AA, Alghamdi H, Alswat H, Edrees BM, Ahmad I, Nasr A. Changes in the levels of cytokines in both diabetic/non-diabetic type I children living in a moderate altitude area in Saudi Arabia. High Alt Med Biol 2014; 15:380-7. [PMID: 25167161 DOI: 10.1089/ham.2014.1001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The aim of the present study was to investigate the possible effects of living in moderate altitude area on pro/anti-inflammatory cytokines profile (IFN-γ, TNF-α, IL-6, IL-1β, IL-10, and IL-4) among type I diabetic (T1D) and non- T1D children compared with those living at sea level area. A prospective clinical study was carried out at pediatric outpatient endocrine clinics in Taif City, which is a moderate altitude area in Saudi Arabia, that stands about 1800-2000 meters above sea-level; and in Mecca City, which is a sea level area, that lies in the middle west of Saudi Arabia. Hemoglobin A1c (HbA1c) percentage was estimated and cytokine measurements were performed in sera by flow cytometry using Cytometric Bead Array (CBA) technology. In this study we included 600 children who were consecutively enrolled (sex and age were matched). The HbA1c was statistically significantly higher in children living in moderate altitude compared to those living at sea level (overall p<0.001). Furthermore, T1D patients had higher values of serum cytokine levels (IFN-γ, TNF-α, IL-6, IL-1β, IL-4, and IL-10) in comparison to non-T1D control group (overall p<0.001). In conclusion, the data of the present study clearly showed that in both T1D and non-T1D children, moderate altitude-natives expressed high HbA1c and both pro-and anti-inflammatory cytokines. Type I diabetic children living in moderate altitude or at sea level showed elevated levels of IFN-γ, TNF-α, IL-6, IL-1β, IL-4, and IL-10 than control subjects. Glycemic control in non-diabetic children was affected by living in moderate altitude, however, HbA1c significantly increased in diabetic children living in moderate altitude.
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Affiliation(s)
- Gamal Allam
- 1 High Altitude Research Center, Taif University , Taif, Saudi Arabia
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18
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de Mol P, de Vries ST, de Koning EJP, Gans ROB, Bilo HJG, Tack CJ. Physical activity at altitude: challenges for people with diabetes: a review. Diabetes Care 2014; 37:2404-13. [PMID: 25061142 DOI: 10.2337/dc13-2302] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
BACKGROUND A growing number of subjects with diabetes take part in physical activities at altitude such as skiing, climbing, and trekking. Exercise under conditions of hypobaric hypoxia poses some unique challenges on subjects with diabetes, and the presence of diabetes can complicate safe and successful participation in mountain activities. Among others, altitude can alter glucoregulation. Furthermore, cold temperatures and altitude can complicate accurate reading of glucose monitoring equipment and storage of insulin. These factors potentially lead to dangerous hyperglycemia or hypoglycemia. Over the last years, more information has become available on this subject. PURPOSE To provide an up-to-date overview of the pathophysiological changes during physical activity at altitude and the potential problems related to diabetes, including the use of (continuous) blood glucose monitors and insulin pumps. To propose practical recommendations for preparations and travel to altitude for subjects with diabetes. DATA SOURCES AND SYNTHESIS We researched PubMed, medical textbooks, and related Internet sites, and extracted human studies and data based on relevance for diabetes, exercise, and altitude. LIMITATIONS Given the paucity of controlled trials regarding diabetes and altitude, we composed a narrative review and filled in areas lacking diabetes-specific studies with data obtained from nondiabetic subjects. CONCLUSIONS Subjects with diabetes can take part in activities at high, and even extreme, altitude. However, careful assessment of diabetes-related complications, optimal preparation, and adequate knowledge of glycemic regulation at altitude and altitude-related complications is needed.
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Affiliation(s)
- Pieter de Mol
- Department of Internal Medicine, Radboud University Nijmegen Medical Centre, Nijmegen, the Netherlands
| | - Suzanna T de Vries
- Department of Cardiology, Tjongerschans Hospital, Heerenveen, the Netherlands
| | - Eelco J P de Koning
- Department of Endocrinology, Leiden University Medical Centre, Leiden, the NetherlandsDepartment of Nephrology, Leiden University Medical Centre, Leiden, the Netherlands
| | - Reinold O B Gans
- Department of Internal Medicine, University Medical Centre Groningen, Groningen, the Netherlands
| | - Henk J G Bilo
- Department of Internal Medicine, University Medical Centre Groningen, Groningen, the NetherlandsDepartment of Internal Medicine, Isala Clinics, Zwolle, the Netherlands
| | - Cees J Tack
- Department of Internal Medicine, Radboud University Nijmegen Medical Centre, Nijmegen, the Netherlands
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Siervo M, Riley HL, Fernandez BO, Leckstrom CA, Martin DS, Mitchell K, Levett DZH, Montgomery HE, Mythen MG, Grocott MPW, Feelisch M. Effects of prolonged exposure to hypobaric hypoxia on oxidative stress, inflammation and gluco-insular regulation: the not-so-sweet price for good regulation. PLoS One 2014; 9:e94915. [PMID: 24733551 PMCID: PMC3986261 DOI: 10.1371/journal.pone.0094915] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2013] [Accepted: 03/21/2014] [Indexed: 12/29/2022] Open
Abstract
OBJECTIVES The mechanisms by which low oxygen availability are associated with the development of insulin resistance remain obscure. We thus investigated the relationship between such gluco-insular derangements in response to sustained (hypobaric) hypoxemia, and changes in biomarkers of oxidative stress, inflammation and counter-regulatory hormone responses. METHODS After baseline testing in London (75 m), 24 subjects ascended from Kathmandu (1,300 m) to Everest Base Camp (EBC;5,300 m) over 13 days. Of these, 14 ascended higher, with 8 reaching the summit (8,848 m). Assessments were conducted at baseline, during ascent to EBC, and 1, 6 and 8 week(s) thereafter. Changes in body weight and indices of gluco-insular control were measured (glucose, insulin, C-Peptide, homeostasis model assessment of insulin resistance [HOMA-IR]) along with biomarkers of oxidative stress (4-hydroxy-2-nonenal-HNE), inflammation (Interleukin-6 [IL-6]) and counter-regulatory hormones (glucagon, adrenalin, noradrenalin). In addition, peripheral oxygen saturation (SpO2) and venous blood lactate concentrations were determined. RESULTS SpO2 fell significantly from 98.0% at sea level to 82.0% on arrival at 5,300 m. Whilst glucose levels remained stable, insulin and C-Peptide concentrations increased by >200% during the last 2 weeks. Increases in fasting insulin, HOMA-IR and glucagon correlated with increases in markers of oxidative stress (4-HNE) and inflammation (IL-6). Lactate levels progressively increased during ascent and remained significantly elevated until week 8. Subjects lost on average 7.3 kg in body weight. CONCLUSIONS Sustained hypoxemia is associated with insulin resistance, whose magnitude correlates with the degree of oxidative stress and inflammation. The role of 4-HNE and IL-6 as key players in modifying the association between sustained hypoxia and insulin resistance merits further investigation.
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Affiliation(s)
- Mario Siervo
- Human Nutrition Research Centre, Institute for Ageing and Health, Newcastle University, Newcastle on Tyne, United Kingdom
| | - Heather L. Riley
- Warwick Systems Biology Centre, University of Warwick, Coventry, United Kingdom
| | - Bernadette O. Fernandez
- Warwick Medical School, University of Warwick, Coventry, United Kingdom
- University of Southampton, Clinical & Experimental Sciences, Faculty of Medicine, Southampton General Hospital, Southampton, United Kingdom
| | - Carl A. Leckstrom
- Warwick Medical School, University of Warwick, Coventry, United Kingdom
| | - Daniel S. Martin
- Centre for Altitude Space and Extreme Environment Medicine, Portex Unit, UCL Institute of Child Health, London, United Kingdom
- Division of Surgery and Interventional Science, University College London, Royal Free Hospital, London, United Kingdom
| | - Kay Mitchell
- Centre for Altitude Space and Extreme Environment Medicine, Portex Unit, UCL Institute of Child Health, London, United Kingdom
- University Hospital Southampton NHS Foundation Trust, Southampton General Hospital, Southampton, United Kingdom
| | - Denny Z. H. Levett
- Centre for Altitude Space and Extreme Environment Medicine, Portex Unit, UCL Institute of Child Health, London, United Kingdom
- University Hospital Southampton NHS Foundation Trust, Southampton General Hospital, Southampton, United Kingdom
- Southampton NIHR Respiratory Biomedical Research Unit, Southampton, United Kingdom
| | - Hugh E. Montgomery
- Centre for Altitude Space and Extreme Environment Medicine, Portex Unit, UCL Institute of Child Health, London, United Kingdom
| | - Monty G. Mythen
- Centre for Altitude Space and Extreme Environment Medicine, Portex Unit, UCL Institute of Child Health, London, United Kingdom
| | - Michael P. W. Grocott
- University of Southampton, Clinical & Experimental Sciences, Faculty of Medicine, Southampton General Hospital, Southampton, United Kingdom
- Centre for Altitude Space and Extreme Environment Medicine, Portex Unit, UCL Institute of Child Health, London, United Kingdom
- University Hospital Southampton NHS Foundation Trust, Southampton General Hospital, Southampton, United Kingdom
- Southampton NIHR Respiratory Biomedical Research Unit, Southampton, United Kingdom
| | - Martin Feelisch
- Warwick Systems Biology Centre, University of Warwick, Coventry, United Kingdom
- Warwick Medical School, University of Warwick, Coventry, United Kingdom
- University of Southampton, Clinical & Experimental Sciences, Faculty of Medicine, Southampton General Hospital, Southampton, United Kingdom
- Southampton NIHR Respiratory Biomedical Research Unit, Southampton, United Kingdom
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Basu M, Malhotra AS, Pal K, Chatterjee T, Ghosh D, Haldar K, Verma SK, Kumar S, Sharma YK, Sawhney RC. Determination of bone mass using multisite quantitative ultrasound and biochemical markers of bone turnover during residency at extreme altitude: a longitudinal study. High Alt Med Biol 2014; 14:150-4. [PMID: 23795735 DOI: 10.1089/ham.2012.1042] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
A group of 221 male healthy volunteers of Indian Army were the subjects of the study. The baseline parameters of skeletal health were measured during their residency at an altitude of 3542 m. These subjects were then taken to an extreme altitude (EA, 5400-6700 m) where they stayed for about 4 months. The study parameters were repeated following their de-induction (DI) to 3542 m. On random selection, a subgroup was constituted from the above mentioned volunteers for detailed investigations on various bone turnover markers. Results of this study indicate a loss of body weight after DI from EA. The bone impairment was detected at the proximal phalanx, which is known to undergo early morpho-structural changes associated with bone resorption. The intact parathyroid hormone (i-PTH) levels showed a significant increase, while alkaline phosphatase (ALP) and bone specific alkaline phosphatase (BAP) activities declined significantly after DI from EA. This elevation in i-PTH might be required for maintenance of blood Ca level. 25 (OH) Vitamin D3 (25VitD) and calcitonin (CT) also showed a significant decline, which may suggest a negative impact on bone formation during sojourn at EA. The causes of deterioration of skeletal health at EA although are poorly understood but may be due to acute hypoxemia arising from extreme hypobaric hypoxia prevalent at extreme altitude.
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Affiliation(s)
- Minakshi Basu
- Defence Institute of Physiology and Allied Sciences, Timarpur, Delhi, India.
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Oliver SJ, Macdonald JH, Harper Smith AD, Lawley JS, Gallagher CA, Di Felice U, Walsh NP. High altitude impairs in vivo immunity in humans. High Alt Med Biol 2014; 14:144-9. [PMID: 23795734 DOI: 10.1089/ham.2012.1070] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The aim was to assess the effect of high altitude on the development of new immune memory (induction) using a contact sensitization model of in vivo immunity. We hypothesized that high-altitude exposure would impair induction of the in vivo immune response to a novel antigen, diphenylcyclopropenone (DPCP). DPCP was applied (sensitization) to the lower back of 27 rested controls at sea level and to ten rested mountaineers 28 hours after passive ascent to 3777 m. After sensitization, mountaineers avoided strenuous exercise for a further 24 hours, after which they completed alpine activities for 11-18 days. Exactly 4 weeks after sensitization, the strength of immune memory induction was quantified in rested mountaineers and controls at sea level, by measuring the response to a low, dose-series DPCP challenge, read at 48 hours as skin measures of edema (skinfold thickness) and redness (erythema). Compared with control responses, skinfold thickness and erythema were reduced in the mountaineers (skinfold thickness,-52%, p=0.01, d=0.86; erythema, -36%, p=0.02, d=0.77). These changes in skinfold thickness and erythema were related to arterial oxygen saturation (r=0.7, p=0.04), but not cortisol (r<0.1, p>0.79), at sensitization. In conclusion, this is the first study to show, using a contact sensitization model of in vivo immunity, that high altitude exposure impairs the development of new immunity in humans.
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Affiliation(s)
- Samuel J Oliver
- Extremes Research Group, School of Sport, Health and Exercise Sciences, Bangor University, Bangor, Gwynedd, United Kingdom.
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Li Y, Wu DD, Boyko AR, Wang GD, Wu SF, Irwin DM, Zhang YP. Population Variation Revealed High-Altitude Adaptation of Tibetan Mastiffs. Mol Biol Evol 2014; 31:1200-5. [DOI: 10.1093/molbev/msu070] [Citation(s) in RCA: 93] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
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Park JY, Hwang TK, Park HK, Ahn RS. Differences in cardiovascular and hypothalamic-pituitary-adrenal axis functions between high-altitude visitors and natives during a trek on the Annapurna circuit. Neuroendocrinology 2014; 99:130-8. [PMID: 24821470 DOI: 10.1159/000363367] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/12/2014] [Accepted: 04/29/2014] [Indexed: 11/19/2022]
Abstract
OBJECTIVE Differences in the cardiovascular and hypothalamic-pituitary-adrenal (HPA) axis functions at high altitudes (HAs) between visitors to and natives of HA were examined. METHODS The cardiovascular functions and peripheral oxygen saturation (SPO2) were monitored, and the cortisol awakening response (CAR) and nighttime cortisol concentration (NCC), as indices of the HPA axis function, were determined in 25 trekkers and 21 Sherpas during an Annapurna circuit trek. RESULTS SPO2 decreased less in the Sherpas than in the trekkers at HAs (3,540, 3,800, and 4,800 m). Blood pressure and heart rate in the Sherpas changed concurrently during the trek; however, a tachycardic response occurred without changes in blood pressure in the trekkers at HAs. The CAR and NCC at HAs in the trekkers differed from those observed at 1,100 m and those observed at HAs in the Sherpas. The trekkers exhibited an elevated morning cortisol level at 3,540 and 3,800 m, a heightened CAR at 4,800 m, and an elevated NCC at 3,800 m. Alteration of the CAR resulted in an increase in the integrated volume of cortisol released within the first hour after awakening (CARauc) in the trekkers. The changes in SPO2 occurred concurrently with the changes in the CARauc and the heart rate in the trekkers. CONCLUSIONS The alterations of CAR occurred at HAs where blood pressure levels reached a peak plateau, which is associated with an increase in heart rate at HAs in the trekkers. The CAR was unaltered in the Sherpas during the trek.
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Affiliation(s)
- Jai Y Park
- Department of Anesthesiology and Pain Medicine, The Armed Forces Capital Hospital, Seoul, Republic of Korea
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Abstract
There is a growing public awareness that hormones can have a significant impact on most biological systems, including the control of breathing. This review will focus on the actions of two broad classes of hormones on the neuronal control of breathing: sex hormones and stress hormones. The majority of these hormones are steroids; a striking feature is that both groups are derived from cholesterol. Stress hormones also include many peptides which are produced primarily within the paraventricular nucleus of the hypothalamus (PVN) and secreted into the brain or into the circulatory system. In this article we will first review and discuss the role of sex hormones in respiratory control throughout life, emphasizing how natural fluctuations in hormones are reflected in ventilatory metrics and how disruption of their endogenous cycle can predispose to respiratory disease. These effects may be mediated directly by sex hormone receptors or indirectly by neurotransmitter systems. Next, we will discuss the origins of hypothalamic stress hormones and their relationship with the respiratory control system. This relationship is 2-fold: (i) via direct anatomical connections to brainstem respiratory control centers, and (ii) via steroid hormones released from the adrenal gland in response to signals from the pituitary gland. Finally, the impact of stress on the development of neural circuits involved in breathing is evaluated in animal models, and the consequences of early stress on respiratory health and disease is discussed.
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Affiliation(s)
- Mary Behan
- Department of Comparative Biosciences, University of Wisconsin, Madison, Wisconsin, USA.
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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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Seys SF, Daenen M, Dilissen E, Van Thienen R, Bullens DMA, Hespel P, Dupont LJ. Effects of high altitude and cold air exposure on airway inflammation in patients with asthma. Thorax 2013; 68:906-13. [PMID: 23821393 DOI: 10.1136/thoraxjnl-2013-203280] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
AIMS Eighteen patients with asthma were evaluated during preparation to climb to extreme altitude in order to study the effects of low fractional inspired oxygen (FiO(2)), prolonged exposure to cold air and high altitude on lung function, asthma control and airway inflammation. METHODS Spirometry and airway inflammation (fractional exhaled nitric oxide (FeNO) and induced sputum) were studied under different test conditions: hypoxic (FiO(2)=11%) exercise test, 24-hour cold exposure (-5°C) and before, during and after an expedition that involved climbing the Aconcagua mountain (6965 m). RESULTS Forced expiratory volume in 1 s (FEV(1)) and FeNO values were slightly lower (p<0.04) after 1 h of normobaric hypoxia. FEV(1) decreased (p=0.009) after 24-hour cold exposure, accompanied by increased sputum neutrophilia (p<0.01). During the expedition FEV(1) and forced vital capacity decreased (maximum FEV(1) decrease of 12.3% at 4300 m) and asthma symptoms slightly increased. After the expedition the Asthma Control Test score and prebronchodilator FEV(1) were reduced (p<0.02), sputum neutrophil count was increased (p=0.04) and sputum myeloperoxidase levels, sputum interleukin 17 mRNA, serum and sputum vascular endothelial growth factor A levels were significantly higher compared with baseline. Patients with asthma with the lowest oxygen saturation during the hypoxic exercise test were more prone to develop acute mountain sickness. CONCLUSIONS Exposure to environmental conditions at high altitude (hypoxia, exercise, cold) was associated with a moderate loss of asthma control, increased airway obstruction and neutrophilic airway inflammation. The cold temperature is probably the most important contributing factor as 24-hour cold exposure by itself induced similar effects.
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Affiliation(s)
- Sven F Seys
- Department of Immunology and Microbiology, Laboratory of Clinical Immunology, KU Leuven, , Leuven, Belgium
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Smith JD, Cianflone K, Martin J, Poirier P, Broderick TL, Noël M. Plasma adipokine and hormone changes in mountaineers on ascent to 5300 meters. Wilderness Environ Med 2011; 22:107-14. [PMID: 21664558 DOI: 10.1016/j.wem.2011.01.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2010] [Revised: 12/06/2010] [Accepted: 01/13/2011] [Indexed: 01/12/2023]
Abstract
OBJECTIVE The current study evaluated multiple metabolic and inflammatory hormone responses in recreational climbers (7 men and 3 women, age 26-49 years) over 9 days. In particular, acylation-stimulating protein (ASP), which influences fat storage in adipose tissue, has not been measured at high altitude. METHODS Serial measurements were taken at sea level (SL), or 353 m, on day 0, 4000 m on day 3, 4750 m on day 6, and 5300 m on day 9 of the expedition. RESULTS Body mass index (BMI) decreased upon ascent to 5300 m from SL (SL 23.2 ± 1.5 kg/m(2); 4000 m 23.2 ± 1.4 kg/m(2); 4750 m 22.9 ± 1.3 kg/m(2); 5300 m 22.3 ± 1.2 kg/m(2); P<.001). Similarly, plasma non-esterified fatty acids and triglycerides increased, while HDL cholesterol decreased (P<.05 to <.001) from SL to 5300 m. Acylation-stimulating protein (SL 42.2 ± 40.2 nm; 4000 m 117.0 ± 69.6 nm; 4750 m 107.9 ± 44.5 nm; 5300 m 82.2 ± 20.2 nm; P=.019) and adiponectin (SL 10.4 ± 6.5 ng/mL, 4000 m 13.9 ± 8.5 ng/mL, 4750 m 18.3 ± 8.3 ng/mL, 5300 m 14.7 ± 8.0 ng/mL; P=.015) increased, as did insulin and Interleukin-6 (IL-6) levels (up to 71% and 168%, respectively; P<.05) with no change in leptin, complement C3 (C3), high sensitivity C-reactive protein (hsCRP) or cortisol levels throughout the mountain ascent from SL to 5300 m. CONCLUSION Acylation-stimulating protein and adiponectin are increased during a 9-day period of high altitude (SL to 5300 m) exposure despite weight loss in healthy mountaineers.
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Affiliation(s)
- Jessica D Smith
- Institut Universitaire de Cardiologie et de Pneumologie de Québec, Laval University, Québec, QC, Canada
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Woods D, Stacey M, Hill N, Alwis ND. Endocrine Aspects of High Altitude Acclimatization and Acute Mountain Sickness. J ROY ARMY MED CORPS 2011; 157:33-7. [DOI: 10.1136/jramc-157-01-06] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Richalet JP, Letournel M, Souberbielle JC. Effects of high-altitude hypoxia on the hormonal response to hypothalamic factors. Am J Physiol Regul Integr Comp Physiol 2010; 299:R1685-92. [PMID: 20926759 DOI: 10.1152/ajpregu.00484.2010] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Acute and chronic exposure to high altitude induces various physiological changes, including activation or inhibition of various hormonal systems. In response to activation processes, a desensitization of several pathways has been described, especially in the adrenergic system. In the present study, we aimed to assess whether the hypophyseal hormones are also subjected to a hypoxia-induced decrease in their response to hypothalamic factors. Basal levels of hormones and the responses of TSH, thyroid hormones, prolactin, sex hormones, and growth hormone to the injection of TRH, gonadotropin-releasing hormone, and growth hormone-releasing hormone (GHRH) were studied in eight men in normoxia and on prolonged exposure (3-4 days) to an altitude of 4,350 m. Thyroid hormones were elevated at altitude (+16 to +21%), while TSH levels were unchanged, and follicle-stimulating hormone and prolactin decreased, while leutinizing hormone was unchanged. Norepinephrine and cortisol levels were elevated, while no change was observed in levels of epinephrine, dopamine, growth hormone (GH), IGF-1, and IGFBP-3. The mean response to hypothalamic factors was similar in both altitudes for all studied hormones, although total T4 was lower in hypoxia during 45 to 60 min after injection. The effect of hypoxia on the hypophyseal response to hypothalamic factors was similar among subjects, except for the GH response to GHRH administration. We conclude that prolonged exposure to high-altitude hypoxia induces contrasted changes in hormonal levels, but the hypophyseal response to hypothalamic factors does not appear to be blunted.
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Affiliation(s)
- Jean-Paul Richalet
- Université Paris 13, Unité de Formation et de Recherche Santé Médecine Biologie Humaine, Laboratoire Réponses Cellulaires et Fonctionnelles à l'Hypoxie, Bobigny, France.
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Tamariz LJ, Young JH, Pankow JS, Yeh HC, Schmidt MI, Astor B, Brancati FL. Blood viscosity and hematocrit as risk factors for type 2 diabetes mellitus: the atherosclerosis risk in communities (ARIC) study. Am J Epidemiol 2008; 168:1153-60. [PMID: 18931370 PMCID: PMC2581671 DOI: 10.1093/aje/kwn243] [Citation(s) in RCA: 124] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Several lines of evidence support the notion that elevated blood viscosity may predispose to insulin resistance and type 2 diabetes mellitus by limiting delivery of glucose, insulin, and oxygen to metabolically active tissues. To test this hypothesis, the authors analyzed longitudinal data on 12,881 initially nondiabetic adults, aged 45–64 years, who were participants in the Atherosclerosis Risk in Communities (ARIC) Study (1987–1998). Whole blood viscosity was estimated by using a validated formula based on hematocrit and total plasma proteins at baseline. At baseline, estimated blood viscosity was independently associated with several features of the metabolic syndrome. In models adjusted simultaneously for known predictors of diabetes, estimated whole blood viscosity and hematocrit predicted incident type 2 diabetes mellitus in a graded fashion (Ptrend (linear) < 0.001): Compared with their counterparts in the lowest quartiles, adults in the highest quartile of blood viscosity (hazard ratio = 1.68, 95% confidence interval: 1.53, 1.84) and hematocrit (hazard ratio = 1.63, 95% confidence interval: 1.49, 1.79) were over 60% more likely to develop diabetes. Therefore, elevated blood viscosity and hematocrit deserve attention as emerging risk factors for insulin resistance and type 2 diabetes mellitus.
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Lhamo SY, Supamai S, Virasakdi C. Impaired Glucose Regulation in a Sherpa Indigenous Population Living in the Everest Region of Nepal and in Kathmandu Valley. High Alt Med Biol 2008; 9:217-22. [DOI: 10.1089/ham.2008.1011] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Sherpa Y. Lhamo
- Nepal Institute of Health Sciences affiliated to Purbanchal University, Kathmandu, Nepal
| | - Soonthornpun Supamai
- Department of Medicine, Faculty of Medicine, Prince of Songkla University, Hat Yai, Songkhla Thailand
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Chen XQ, Dong J, Niu CY, Fan JM, Du JZ. Effects of hypoxia on glucose, insulin, glucagon, and modulation by corticotropin-releasing factor receptor type 1 in the rat. Endocrinology 2007; 148:3271-8. [PMID: 17379644 DOI: 10.1210/en.2006-1224] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
To determine the influence of continuous hypoxia on body weight, food intake, hepatic glycogen, circulatory glucose, insulin, glucagon, leptin, and corticosterone, and the involvement of the corticotropin-releasing factor receptor type 1 (CRFR1) in modulation of these hormones, rats were exposed to a simulated altitude of 5 km (approximately 10.8% O2) in a hypobaric chamber for 1, 2, 5, 10, and 15 d. Potential involvement of CRFR1 was assessed through five daily sc injections of a CRFR1 antagonist (CP-154,526) prior to hypoxia. Results showed that the levels of body weight, food intake, blood glucose, and plasma insulin were significantly reduced; the content of hepatic glycogen initially and transiently declined, whereas the early plasma glucagon and leptin remarkably increased; plasma corticosterone was markedly increased throughout the hypoxic exposure of 1-15 d. Compared with hypoxia alone, CRFR1 antagonist pretreatment in the hypoxic groups prevented the rise in corticosterone, whereas the levels of body weight and food intake were unchanged. At the same time, the reduction in blood glucose was greater and the pancreatic glucose was increased, plasma insulin reverted toward control, and plasma glucagon decreased. In summary, prolonged hypoxia reduced body weight, food intake, blood glucose, and plasma insulin but transiently enhanced plasma glucagon and leptin. In conclusion, CRFR1 is potentially involved in the plasma insulin reduction and transient glucagon increase in hypoxic rats.
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Affiliation(s)
- Xue-Qun Chen
- Division of Neurobiology and Physiology, College of Life Sciences, School of Medicine, Zhejiang University, Hangzhou 310058, China.
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Abstract
The aim of this paper is to review how preexisting pulmonary diseases can be affected by altitude exposure. Obstructive (asthma and chronic obstructive pulmonary disease or COPD) and restrictive (interstitial pulmonary fibrosis), as well as pulmonary vascular diseases, will be considered, and the goal will be to provide insight and tools to clinicians to optimize the medical condition and thus the life-style of these patients. The underlying pathophysiologies and the effect of hypobaric hypoxia on these diseases will be reviewed such that techniques to assess patients will be appropriate. Therapeutic interventions, including the use of supplemental oxygen, in light of the underlying pathologic processes, will also be discussed.
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Affiliation(s)
- Annalisa Cogo
- Department of Clinical & Experimental Medicine, Section Respiratory Diseases, University of Ferrara, Università via Savonarola 9, 44100 Ferrara, Italy.
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Abstract
This review aims to identify the main issues facing a healthy and well-controlled type-1 diabetic mountaineer at high altitude. Most of the problems are self-managed by the diabetic climber although the risk of serious morbidity or even death remains. Given the scarce evidence on diabetes at altitude, an extensive search of the literature, including case reports and anecdotes was carried out to reach the recommendations.
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Affiliation(s)
- Conxita Leal
- Institut d'Estudis de Medicina de Muntanya, Barcelona, Spain.
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36
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Zaccaria M, Ermolao A, Bonvicini P, Travain G, Varnier M. Decreased serum leptin levels during prolonged high altitude exposure. Eur J Appl Physiol 2004; 92:249-53. [PMID: 15083363 DOI: 10.1007/s00421-004-1070-0] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/21/2004] [Indexed: 11/24/2022]
Abstract
Circulating leptin concentrations are shown to be influenced not only by hormones, but also by body weight and energy balance. High altitude (HA) exposure induces a daily negative energy balance and stress hormone activation. The aim of our study was to evaluate leptin concentration during both acute and prolonged HA exposure and its correlations with some metabolic and hormonal parameters. Twelve males were studied during a stay at HA (15-20 days at 5,050 m). Blood samples for serum leptin, plasma insulin and 24-h urinary epinephrine (E) and norepinephrine (NE) were collected at sea level (SL), at the arrival at HA (A) and after 12-16 days (C) of stay. Symptoms of Acute Mountain Sickness (AMS) were evaluated using the Lake Louise score and the results showed there was no relationship with leptin concentrations. During the stay, both body mass index and leptin levels significantly decreased in both groups [leptin from 1.88 (1.12) to 1.21 (1.04) ng/ml, P<0.008, in A; and to 1.06 (0.74) ng/ml, P<0.003, in C]. Acute HA exposure induced a clear-cut significant increase of NE ( P<0.001 in A, P<0.003 in C) while E and insulin levels were unchanged in both phases. Moreover, a significant correlation between leptin and NE absolute values, and leptin and insulin variations was found ( r 0.359, P<0.034 and r=0.560, P<0.007, respectively). Exposure to HA induces a decrease in fasting serum leptin concentrations in men. These changes are not linked to symptoms of AMS but to hormonal and energy balance variations, suggesting that leptin is involved in the endocrine and metabolic adaptations occurring during HA exposure.
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Affiliation(s)
- Marco Zaccaria
- Sports Medicine Unit, Department of Medical and Surgical Sciences, University of Padova, Ospedale Busonera, Via Gattamelata 64, 35128, Padua, Italy. marco.zaccaria @unipd.it
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Vats P, Singh SN, Shyam R, Singh VK, Singh SB, Banerjee PK, Selvamurthy W. Leptin May Not Be Responsible for High Altitude Anorexia. High Alt Med Biol 2004; 5:90-2. [PMID: 15072723 DOI: 10.1089/152702904322963753] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Okumura A, Fuse H, Kawauchi Y, Mizuno I, Akashi T. Changes in Male Reproductive Function after High Altitude Mountaineering. High Alt Med Biol 2003; 4:349-53. [PMID: 14561240 DOI: 10.1089/152702903769192304] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
Abstract
The male reproductive functions of the members of the Masherbrum (7821 m) Expedition in 1999 were examined via semen analyses and endocrine tests. Specimens were collected from three subjects who had stayed above 5100 m for 21 to 24 days and above 6700 m for 4 to 5 days before departure and 1 month, 3 months, and 2 yr after returning from the expedition. Semen analyses showed no change in the semen volume. Sperm counts decreased after 1 month and had not recovered after 3 months, but they had recovered after 2 yr in all subjects. An increase in abnormally shaped sperm was also observed after 1 month, but had nearly recovered to the preexpedition state after 3 months. Endocrine tests revealed slightly decreased testosterone in the blood after 1 month, which had decreased still further after 3 months. The tests were completely normal after 2 yr. We suggest that a high altitude sojourn may induce reversible spermatogenic and Leydig cell dysfunction.
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Affiliation(s)
- Akiou Okumura
- Department of Urology, Faculty of Medicine, Toyama Medical and Pharmaceutical University, 2630 Sugitani, Toyama, Japan.
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40
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Basu M, Sawhney RC, Kumar S, Pal K, Prasad R, Selvamurthy W. Glucocorticoids as prophylaxis against acute mountain sickness. Clin Endocrinol (Oxf) 2002; 57:761-7. [PMID: 12460326 DOI: 10.1046/j.1365-2265.2002.01664.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE Acute mountain sickness (AMS) characterized by presence of symptoms including headache, nausea, excessive fatigue, loss of appetite, irritability and insomnia is a major impediment to work performance in human subjects who are rapidly inducted to high altitude (HA) during the initial phase of induction. The present study aims at to evaluate the efficacy of prophylactic administration of low dose glucocorticoids in prevention of AMS in normal healthy men who are inducted to HA by air. DESIGN Fifty healthy men were randomly divided into five groups of 10 each. Group I received prednisolone (Pred) 10 mg, Group II Pred 20 mg, Group III Pred 40 mg, Group IV dexamethasone 0.5 mg, Group V received placebo once a day in the morning for 2 days at sea level (SL) and for 3 days on arrival at an altitude of 3450 m by air. MEASUREMENTS The severity of AMS was assessed using Lake Louise AMS scoring system. Physiological parameters like blood pressure, respiratory rate, peripheral blood O2 saturation and heart rate were measured at sea level and on arrival at HA. Circulatory levels of cortisol and adrenocorticotropic hormone (ACTH) were measured by radioimmunoassay (RIA) and immunoradiometreic assay (IRMA), respectively. RESULTS In the placebo group, significant AMS could be detected at 12 h of arrival at HA, peaked by day 1 or 2 of stay and started declining thereafter. As compared to the placebo group, the steroid treated groups showed a significant (P < 0.01) reduction in daily AMS score. When compared with prednisolone 10 mg, 40 mg and dexamethasone groups, the prednisolone 20 mg group showed an optimal response in reduction of AMS symptoms. The O2 saturation showed a significant decline (P < 0.001) on arrival at HA, but the pattern of O2 saturation in placebo and glucocorticoid groups was identical. Similarly, the rise in heart rate and blood pressure and on day 3 of stay at HA was similar in placebo and glucocorticoid-treated groups. An increase in plasma cortisol in placebo group was observed on day 3 of stay at HA and continued to rise till day 8 of observations. The cortisol levels in Pred 10 mg and Pred 20 mg groups on day 1 and 3 of arrival at HA were not significantly different than the SL post-treatment values but were found to be significantly higher on day 8 of stay. Plasma cortisol in Pred 40 mg and dexamethasone groups was significantly lower (P < 0.01) on day 1 and 3 of stay but showed an increase by day 8 of stay. The ACTH levels were increased at HA in placebo group but did not show any significant change till day 3 of stay in steroid treated subjects and were found to be higher in all groups on day 8 of observations. CONCLUSION These observations suggest that administration of low-dose glucocorticoids can curtail acute mountain sickness significantly without influencing the normal adreno cortical response to hypoxia.
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Affiliation(s)
- M Basu
- Defence Institute of Physiology & Allied Sciences, Lucknow Road, Timarpur, Delhi-110054, India.
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Greene HM, Cogger EA, Miltenberger TL, Koch AK, Bray RE, Wickler SJ. Metabolic and osmoregulatory function at low and high (3800 m) altitude. Equine Vet J 2002:545-50. [PMID: 12405748 DOI: 10.1111/j.2042-3306.2002.tb05480.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Altitude evokes physiological adjustments that include not only respiratory and cardiovascular properties, but also metabolic function, renal and endocrine responses. The purpose of the present study was designed to expand our understanding of the physiological process involved with acclimatisation to high altitude in equids. The study examined temporal effects on metabolic and osmoregulatory function in horses (n = 6) at rest and postexercise at 3800 m. Animals were studied at 225 m (Pb = 743 mmHg) and during a 10 day stay at altitude (Pb = 487 mmHg). Rest samples were taken 90 min postprandial at 0830 h and immediately after the gallop phase of a standard exercise test. Changes in glucose, insulin, cortisol, thyroxine, sodium, potassium, chloride and total protein were assessed at both altitudes. Exercise stimulated increases in cortisol, thyroxine, potassium, and chloride; while the concentrations of glucose, insulin, sodium and total protein (regardless of altitude) decreased. Acute (Day 2) altitude exposure (following transport stress) produced significant increases in glucose, cortisol, thyroxine, chloride and protein at rest and exercise. All variables (except cortisol) appeared to stabilise by Day 4 of altitude exposure. Observations from these data (coupled with haematological and blood gases data) indicate that equids acutely acclimate within 2-3 days to this altitude.
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Affiliation(s)
- H M Greene
- The University of California, White Mountain Research Station, Bishop 93514, USA
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Capoğlu I, Unüvar N, Bektaş Y, Yilmaz O, Kaya MD. The effects of high haematocrit levels on glucose metabolism disorders. J Int Med Res 2002; 30:433-7. [PMID: 12235927 DOI: 10.1177/147323000203000411] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
There has been only limited research investigating the possible association between raised haematocrit levels, glucose intolerance and type 2 diabetes. In the present study, we explored the association between high haematocrit levels and impaired glucose tolerance by performing oral glucose tolerance tests in 46 patients with chronic obstructive pulmonary disease and no previous history of diabetes mellitus or glucose intolerance. A glucose metabolism disorder was observed in 12 (26%) patients (type 2 diabetes in six patients and impaired glucose tolerance in a further six). There was a significant association between high haematocrit levels and the presence of a glucose metabolism disorder, which was independent of other risk factors. High haematocrit levels may be an independent risk factor for type 2 diabetes and impaired glucose tolerance.
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Affiliation(s)
- I Capoğlu
- Division of Endocrinology and Metabolism, Atatürk University Medical Faculty, Erzurum, Turkey
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McClelland GB, Hochachka PW, Reidy SP, Weber JM. High-altitude acclimation increases the triacylglycerol/fatty acid cycle at rest and during exercise. Am J Physiol Endocrinol Metab 2001; 281:E537-44. [PMID: 11500309 DOI: 10.1152/ajpendo.2001.281.3.e537] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
High-altitude acclimation alters lipid metabolism during exercise, but it is unknown whether this involves changes in rates of lipolysis or reesterification, which form the triacylglycerol/fatty acid (TAG/FA) cycle. We combined indirect calorimetry with [2-(3)H]glycerol and [1-(14)C]palmitate infusions to simultaneously measure total lipid oxidation, lipolysis, and rate of appearance (R(a)) of nonesterified fatty acids (NEFA) in high-altitude-acclimated (HA) rats exercising at 60% maximal O(2) uptake (VO(2 max)). During exercise, relative total lipid oxidation (%VO(2)) equaled sea-level control (SL) values; however, acclimation greatly stimulated lipolysis (+75%) but had no effect on R(a) NEFA. As a result, TAG/FA cycling increased (+119%), due solely to an increase in recycling (+144%) within adipocytes. There was no change in either group in these variables with the transition from rest to exercise. We conclude that, in HA, 1) acclimation is a potent stimulator of lipolysis; 2) rats do not modify TAG/FA cycling with the transition to exercise; and 3) in normoxia, HA and SL derive the same fraction of their total energy from lipids and carbohydrates.
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Affiliation(s)
- G B McClelland
- Department of Zoology, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada.
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Braun B, Rock PB, Zamudio S, Wolfel GE, Mazzeo RS, Muza SR, Fulco CS, Moore LG, Butterfield GE. Women at altitude: short-term exposure to hypoxia and/or alpha(1)-adrenergic blockade reduces insulin sensitivity. J Appl Physiol (1985) 2001; 91:623-31. [PMID: 11457773 DOI: 10.1152/jappl.2001.91.2.623] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
After short-term exposure to high altitude (HA), men appear to be less sensitive to insulin than at sea level (SL). We hypothesized that the same would be true in women, that reduced insulin sensitivity would be directly related to the rise in plasma epinephrine concentrations at altitude, and that the addition of alpha-adrenergic blockade would potentiate the reduction. To test the hypotheses, 12 women consumed a high-carbohydrate meal at SL and after 16 h at simulated 4,300-m elevation (HA). Subjects were studied twice at each elevation: once with prazosin (Prz), an alpha(1)-adrenergic antagonist, and once with placebo (Pla). Mathematical models were used to assess insulin resistance based on fasting [homeostasis model assessment of insulin resistance (HOMA-IR)] and postprandial [composite model insulin sensitivity index (C-ISI)] glucose and insulin concentrations. Relative to SL-Pla (HOMA-IR: 1.86 +/- 0.35), insulin resistance was greater in HA-Pla (3.00 +/- 0.45; P < 0.05), SL-Prz (3.46 +/- 0.51; P < 0.01), and HA-Prz (2.82 +/- 0.43; P < 0.05). Insulin sensitivity was reduced in HA-Pla (C-ISI: 4.41 +/- 1.03; P < 0.01), SL-Prz (5.73 +/- 1.01; P < 0.05), and HA-Prz (4.18 +/- 0.99; P < 0.01) relative to SL-Pla (8.02 +/- 0.92). Plasma epinephrine was significantly elevated in HA-Pla (0.57 +/- 0.08 ng/ml; P < 0.01), SL-Prz (0.42 +/- 0.07; P < 0.05), and HA-Prz (0.82 +/- 0.07; P < 0.01) relative to SL-Pla (0.28 +/- 0.04), but correlations with HOMA-IR, HOMA-beta-cell function, and C-ISI were weak. In women, short-term exposure to simulated HA reduced insulin sensitivity compared with SL. The change does not appear to be directly mediated by a concurrent rise in plasma epinephrine concentrations.
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Affiliation(s)
- B Braun
- Geriatric Research, Education and Clinical Center, Veterans Affairs Health Care System, Stanford University School of Medicine, Palo Alto, California 94304, USA.
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Malhotra AS, Pal K, Prasad R, Bajaj AC, Kumar R, Sawhney RC. Plasma insulin and growth hormone during antarctic residence. THE JAPANESE JOURNAL OF PHYSIOLOGY 1998; 48:167-9. [PMID: 9639553 DOI: 10.2170/jjphysiol.48.167] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Circulatory levels of insulin and growth hormone (GH) were estimated in nine tropical euglycemic men in New Delhi and during the first week of every month of stay in Dakshin Gangotri, Antarctica. Prolonged residency in Antarctica did not alter GH levels because mean GH values during Austral summer and Austral winter were not significantly different from the New Delhi values. Compared with GH, the insulin levels during March, April, and June were found to be significantly lower than the New Delhi values. In Antarctica, the insulin levels in March, April, May, June, July, and August were also found to be significantly lower than the December values. This decline in insulin in Antarctica might be important in increasing substrate availability for heat production by facilitating lipolysis and hepatic glucose output.
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Affiliation(s)
- A S Malhotra
- Department of Endocrinology and Metabolism, Defence Institute of Physiology and Allied Sciences,Timarpur, Delhi, 110 054, India
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Larsen JJ, Hansen JM, Olsen NV, Galbo H, Dela F. The effect of altitude hypoxia on glucose homeostasis in men. J Physiol 1997; 504 ( Pt 1):241-9. [PMID: 9350634 PMCID: PMC1159952 DOI: 10.1111/j.1469-7793.1997.241bf.x] [Citation(s) in RCA: 149] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
1. Exposure to altitude hypoxia elicits changes in glucose homeostasis with increases in glucose and insulin concentrations within the first few days at altitude. Both increased and unchanged hepatic glucose production (HGP) have previously been reported in response to acute altitude hypoxia. Insulin action on glucose uptake has never been investigated during altitude hypoxia. 2. In eight healthy, sea level resident men (27 +/- 1 years (mean +/- S.E.M); weight, 72 +/- 2 kg; height, 182 +/- 2 cm) hyperinsulinaemic (50 mU min-1 m-2), euglycaemic clamps were carried out at sea level, and subsequently on days 2 and 7 after a rapid passive ascent to an altitude of 4559 m. 3. Acute mountain sickness scores increased in the first days of altitude exposure, with a peak on day 2. Basal HGP did not change with the transition from sea level (2.2 +/- 0.2 mg min-1 kg-1) to altitude (2.0 +/- 0.1 and 2.1 +/- 0.2 mg min-1 kg-1, days 2 and 7, respectively). Insulin-stimulated glucose uptake rate was halved on day two compared with sea level (4.5 +/- 0.6 and 9.8 +/- 1.1 mg min-1 kg-1, respectively; P < 0.05), and was partly restored on day 7 (7.4 +/- 1.4 mg min-1 kg-1; P < 0.05 vs. day two and sea level). Concentrations of glucagon and growth hormone remained unchanged, whereas glucose, C-peptide and cortisol increased on day 2. Noradrenaline concentrations increased during the stay at altitude, while adrenaline concentrations remained unchanged. In response to insulin infusion, catecholamines increased on day 2 (noradrenaline and adrenaline) and day 7 (adrenaline), but not at sea level. 4. In conclusion, insulin action decreases markedly in response to two days of altitude hypoxia, but improves with more prolonged exposure. HGP is always unchanged. The changes in insulin action may in part be explained by the changes in counter-regulatory hormones.
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Affiliation(s)
- J J Larsen
- Department of Medical Physiology, Panum Institute, University of Copenhagen, Denmark
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Kullmer T, Haak T, Winkelmann BR, Morbitzer D, Jungmann E, Meier-Sydow J. Hormonal modifications in patients admitted to an internal intensive care unit for acute hypoxaemic respiratory failure. Respir Med 1996; 90:601-8. [PMID: 8959117 DOI: 10.1016/s0954-6111(96)90018-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
To clarify which endocrine modifications can be observed in acute hypoxaemic respiratory failure, 15 severely ill male patients [PAT; median age: 61 (range: 48 years); median height: 173 (range: 12) cm; median mass: 73 (range 31) kg] were investigated immediately upon admission to an intensive care unit (ICU) for this clinical disorder. Before starting treatment, the blood gases were measured and a number of selected hormones with special relevance for an ICU setting were determined. These are known to be modified by acute hypoxaemia in healthy subjects and to possess glucoregulatory properties, or an influence upon cardiocirculation or the vascular volume regulation: insulin, cortisol, adrenaline, noradrenaline, atrial natriuretic peptide, renin, aldosterone, angiotensin converting enzyme, and endothelin-I (ET). To elucidate whether potential endocrine changes resulted from acute hypoxaemia alone, the underlying disease, or unspecific influences connected with the ICU setting, all measurements were compared to those of a completely healthy reference group (REF) with comparable acute experimental hypoxaemia. The latter state was achieved by having the REF breathe a gas mixture with the oxygen content reduced to 14% (H). In the REF, neither the medians nor the distribution of endocrinologic measurements were modified significantly by acute hypoxaemia. In the PAT, the medians were increased considerably, yet with a slight diminution of ET. The distribution of individual values was considerably broader than in the REF with H. In conclusion, considerable increases in the means of the above hormones, with the exception of ET, can be registered in severely ill patients admitted to ICUs with acute hypoxaemic failure. However, such modifications cannot be considered attributable exclusively to acute arterial hypoxaemia. The underlying clinical disorders, such as septicaemia or an unspecific endocrine epiphenomenon, including severe and not only hypoxaemic stress, seem to be predominant.
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Affiliation(s)
- T Kullmer
- Department of Internal Medicine I, J.W. Goethe University, Frankfurt am Main, Germany
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Sawhney RC, Malhotra AS, Nair CS, Bajaj AC, Rajan KC, Pal K, Prasad R, Basu M. Thyroid function during a prolonged stay in Antarctica. EUROPEAN JOURNAL OF APPLIED PHYSIOLOGY AND OCCUPATIONAL PHYSIOLOGY 1995; 72:127-33. [PMID: 8789583 DOI: 10.1007/bf00964127] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Adaptation of the thyroid gland to the Antarctic environment was studied in nine healthy euthyroid tropical men of the Sixth Indian Antarctic Expedition during 1 year of their residence at polar latitudes. Circulatory concentrations of thyroid hormones, total T4 (TT4), total T3 (TT3), free T4 (FT4), free T3 (FT3), reverse T3 (rT3), thyroxine binding globulin (TBG), T3 uptake and thyroid stimulating hormone (TSH) were estimated in New Delhi and during the first week of each month of the stay in Antarctica. At the end of the Austral summer in March, the TT3 concentrations were found to be significantly lower (P < 0.01) compared to values recorded in New Delhi and showed a significant increase (P < 0.05) during the Austral winter in August. The mean TT3 concentrations from May to December were found to be significantly higher than the March or April values. Plasma TT4 and rT3 concentrations tended to decline in March but remained unaltered during the entire period in Antarctica. The FT4, FT3, TBG and T3 uptake did not show any appreciable change. Though, the TT3:TT4 ratio tended to decline in March and April suggesting decreased peripheral conversion of T4 to T3 as the possible mechanism for a decline in TT3 in March. physical exertion and prolonged exposure to extreme cold appeared to be the major contributory factors. The TSH concentration in March, April, November and December were found to be significantly higher than the New Delhi values. The morning as well as evening cortisol concentrations during the Austral winter were higher than the March values suggesting that cortisol rhythmicity was well maintained in Antarctica, albeit at a higher level. These observations indicated that the subtle changes in thyroid hormones during a prolonged stay at polar latitudes are related not only to the extreme cold but also to other factors such as physical activity, polar days and polar nights.
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Affiliation(s)
- R C Sawhney
- Defence Institute of Physiology and Allied Sciences, Delhi Cantt, India
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Moan A, Nordby G, Os I, Birkeland KI, Kjeldsen SE. Relationship between hemorrheologic factors and insulin sensitivity in healthy young men. Metabolism 1994; 43:423-7. [PMID: 8159097 DOI: 10.1016/0026-0495(94)90070-1] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The present study aimed at testing a possible relationship between hemorrheologic factors, such as hematocrit, fibrinogen, and whole-blood viscosity, and insulin sensitivity in healthy humans. Twenty-one 21-year-old men were studied with the hyperinsulinemic euglycemic glucose clamp technique. We found statistically significant negative correlations between the glucose disposal rate (GDR) and calculated whole-blood viscosity at both high (r = -.55, P = .01) and low (r = -.51, P = .01) shear rates. We observed negative associations between GDR and fibrinogen (r = -.66, P = .002), GDR and hematocrit (r = -.63, P = .002), GDR and body mass index (r = -.51, P = .007), and GDR and resting heart rate (r = -.46, P = .04). Using stepwise multiple regression considering whole-blood viscosity, body mass index, mean arterial blood pressure, and heart rate as independent variables, we found that only whole-blood viscosity and body mass index were independent explanatory variables of the GDR. Together they accounted for 63% of the variability in the GDR in our subjects. These results suggest hemorrheologic, and therefore indirectly hemodynamic, factors as correlates to insulin sensitivity.
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Affiliation(s)
- A Moan
- Department of Internal Medicine, Ullevaal Hospital, Oslo, Norway
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