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Lawrence ES, Gu W, Bohlender RJ, Anza-Ramirez C, Cole AM, Yu JJ, Hu H, Heinrich EC, O’Brien KA, Vasquez CA, Cowan QT, Bruck PT, Mercader K, Alotaibi M, Long T, Hall JE, Moya EA, Bauk MA, Reeves JJ, Kong MC, Salem RM, Vizcardo-Galindo G, Macarlupu JL, Figueroa-Mujíca R, Bermudez D, Corante N, Gaio E, Fox KP, Salomaa V, Havulinna AS, Murray AJ, Malhotra A, Powel FL, Jain M, Komor AC, Cavalleri GL, Huff CD, Villafuerte FC, Simonson TS. Functional EPAS1/ HIF2A missense variant is associated with hematocrit in Andean highlanders. SCIENCE ADVANCES 2024; 10:eadj5661. [PMID: 38335297 PMCID: PMC10857371 DOI: 10.1126/sciadv.adj5661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Accepted: 01/10/2024] [Indexed: 02/12/2024]
Abstract
Hypoxia-inducible factor pathway genes are linked to adaptation in both human and nonhuman highland species. EPAS1, a notable target of hypoxia adaptation, is associated with relatively lower hemoglobin concentration in Tibetans. We provide evidence for an association between an adaptive EPAS1 variant (rs570553380) and the same phenotype of relatively low hematocrit in Andean highlanders. This Andean-specific missense variant is present at a modest frequency in Andeans and absent in other human populations and vertebrate species except the coelacanth. CRISPR-base-edited human cells with this variant exhibit shifts in hypoxia-regulated gene expression, while metabolomic analyses reveal both genotype and phenotype associations and validation in a lowland population. Although this genocopy of relatively lower hematocrit in Andean highlanders parallels well-replicated findings in Tibetans, it likely involves distinct pathway responses based on a protein-coding versus noncoding variants, respectively. These findings illuminate how unique variants at EPAS1 contribute to the same phenotype in Tibetans and a subset of Andean highlanders despite distinct evolutionary trajectories.
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Affiliation(s)
- Elijah S. Lawrence
- Division of Pulmonary, Critical Care, Sleep Medicine, and Physiology, Department of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Wanjun Gu
- Division of Pulmonary, Critical Care, Sleep Medicine, and Physiology, Department of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Ryan J. Bohlender
- Department of Epidemiology, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Cecilia Anza-Ramirez
- Laboratorio de Fisiología Comparada/Fisiología de del Transporte de Oxígeno-LID, Departamento de Ciencias Biológicas y Fisiológicas, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Perú
| | - Amy M. Cole
- School of Pharmacy and Biomolecular Sciences, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - James J. Yu
- Division of Pulmonary, Critical Care, Sleep Medicine, and Physiology, Department of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Hao Hu
- Department of Epidemiology, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Erica C. Heinrich
- Division of Pulmonary, Critical Care, Sleep Medicine, and Physiology, Department of Medicine, University of California, San Diego, La Jolla, CA, USA
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, CA, USA
| | - Katie A. O’Brien
- Division of Pulmonary, Critical Care, Sleep Medicine, and Physiology, Department of Medicine, University of California, San Diego, La Jolla, CA, USA
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3EG, UK
| | - Carlos A. Vasquez
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA, USA
| | - Quinn T. Cowan
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA, USA
| | - Patrick T. Bruck
- Department of Anthropology and Global Health, University of California, San Diego, La Jolla, CA, USA
| | - Kysha Mercader
- Department of Medicine and Pharmacology, University of California, San Diego, La Jolla, CA, USA
| | - Mona Alotaibi
- Division of Pulmonary, Critical Care, Sleep Medicine, and Physiology, Department of Medicine, University of California, San Diego, La Jolla, CA, USA
- Department of Medicine and Pharmacology, University of California, San Diego, La Jolla, CA, USA
| | - Tao Long
- Department of Medicine and Pharmacology, University of California, San Diego, La Jolla, CA, USA
- Sapient Bioanalytics, LLC, San Diego, CA, USA
| | - James E. Hall
- Division of Pulmonary, Critical Care, Sleep Medicine, and Physiology, Department of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Esteban A. Moya
- Division of Pulmonary, Critical Care, Sleep Medicine, and Physiology, Department of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Marco A. Bauk
- Division of Pulmonary, Critical Care, Sleep Medicine, and Physiology, Department of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Jennifer J. Reeves
- Division of Pulmonary, Critical Care, Sleep Medicine, and Physiology, Department of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Mitchell C. Kong
- Division of Pulmonary, Critical Care, Sleep Medicine, and Physiology, Department of Medicine, University of California, San Diego, La Jolla, CA, USA
- Department of Bioengineering, University of California, San Diego, La Jolla, CA, USA
| | - Rany M. Salem
- Herbert Wertheim School of Public Health and Longevity Sciences, University of California, San Diego, La Jolla, CA, USA
| | - Gustavo Vizcardo-Galindo
- Laboratorio de Fisiología Comparada/Fisiología de del Transporte de Oxígeno-LID, Departamento de Ciencias Biológicas y Fisiológicas, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Perú
| | - Jose-Luis Macarlupu
- Laboratorio de Fisiología Comparada/Fisiología de del Transporte de Oxígeno-LID, Departamento de Ciencias Biológicas y Fisiológicas, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Perú
| | - Rómulo Figueroa-Mujíca
- Laboratorio de Fisiología Comparada/Fisiología de del Transporte de Oxígeno-LID, Departamento de Ciencias Biológicas y Fisiológicas, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Perú
| | - Daniela Bermudez
- Laboratorio de Fisiología Comparada/Fisiología de del Transporte de Oxígeno-LID, Departamento de Ciencias Biológicas y Fisiológicas, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Perú
| | - Noemi Corante
- Laboratorio de Fisiología Comparada/Fisiología de del Transporte de Oxígeno-LID, Departamento de Ciencias Biológicas y Fisiológicas, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Perú
| | - Eduardo Gaio
- Laboratório de Fisiologia Respiratória, Faculdade de Medicina, Universidade de Brasília, Brasília, Brazil
| | - Keolu P. Fox
- Department of Anthropology and Global Health, University of California, San Diego, La Jolla, CA, USA
| | - Veikko Salomaa
- Department of Public Health and Welfare, Finnish Institute for Health and Welfare, Helsinki, Finland
| | - Aki S. Havulinna
- Department of Public Health and Welfare, Finnish Institute for Health and Welfare, Helsinki, Finland
- Institute for Molecular Medicine Finland (FIMM-HiLIFE), Helsinki, Finland
| | - Andrew J. Murray
- Department of Physiology, Development and Neuroscience, University of Cambridge, Cambridge CB2 3EG, UK
| | - Atul Malhotra
- Division of Pulmonary, Critical Care, Sleep Medicine, and Physiology, Department of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Frank L. Powel
- Division of Pulmonary, Critical Care, Sleep Medicine, and Physiology, Department of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Mohit Jain
- Department of Medicine and Pharmacology, University of California, San Diego, La Jolla, CA, USA
- Sapient Bioanalytics, LLC, San Diego, CA, USA
| | - Alexis C. Komor
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA, USA
| | - Gianpiero L. Cavalleri
- School of Pharmacy and Biomolecular Sciences, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Chad D. Huff
- Department of Epidemiology, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Francisco C. Villafuerte
- Laboratorio de Fisiología Comparada/Fisiología de del Transporte de Oxígeno-LID, Departamento de Ciencias Biológicas y Fisiológicas, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Perú
| | - Tatum S. Simonson
- Division of Pulmonary, Critical Care, Sleep Medicine, and Physiology, Department of Medicine, University of California, San Diego, La Jolla, CA, USA
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Anza-Ramírez C, Gu W, Macarlupú JL, Figueroa-Mujíca RJ, Vizcardo-Galindo GA, Heinrich EC, Tift MS, Wagner HE, Wagner PD, Simonson TS, Villafuerte FC. Preserved peak exercise capacity in Andean highlanders with excessive erythrocytosis both before and after isovolumic hemodilution. J Appl Physiol (1985) 2023; 134:36-49. [PMID: 36417198 PMCID: PMC9762978 DOI: 10.1152/japplphysiol.00439.2022] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
In chronic mountain sickness (CMS), increased blood oxygen (O2)-carrying capacity due to excessive erythrocytosis (EE, [Hb] ≥ 21 g/dL) could be offset, especially during exercise by both impaired cardiac output (Q̇t) and O2 diffusion limitation in lungs and muscle. We hypothesized that EE results in reduced peak V̇o2 despite increased blood O2-carrying capacity, and that isovolumic hemodilution (IVHD) improves exercise capacity. In 14 male residents of Cerro de Pasco, Peru (4,340 m), six with and eight without EE, we measured peak cycle-exercise capacity, V̇o2, Q̇t, arterial blood gas parameters, and (resting) blood volume. This was repeated for participants with EE after IVHD, reducing hematocrit by 20% (from 67% to 53%). From these data, we quantified the major O2 transport pathway components (ventilation, pulmonary alveolar-capillary diffusion, Q̇t, and blood-muscle mitochondria diffusion). Participants with EE had similar peak V̇o2, systemic O2 delivery, and O2 extraction as non-EE controls, however, with lower Q̇t and higher arterial [O2]. After IVHD, peak V̇o2 was preserved (but not enhanced), with lower O2 delivery (despite higher Q̇t) balanced by greater O2 extraction. The considerable variance in exercise capacity across the 14 individuals was explained essentially completely by differences in both pulmonary and muscle O2 diffusional conductances and not by any differences in ventilation, [Hb], nor Q̇t. In conclusion, EE does not result in lower peak V̇o2 in Andean males, and IVHD maintains, but does not enhance, exercise capacity.NEW & NOTEWORTHY Male Andean highlanders with and without excessive erythrocytosis (EE) have similar peak V̇o2 at 4,340 m, with higher arterial [O2] in EE and lower cardiac output (Q̇t), thus maintaining similar O2 delivery. Peak V̇o2 in participants with EE was unaffected by isovolumic hemodilution (hematocrit reduced from 67% to 53%), with lower O2 delivery balanced by slightly increased Q̇t and greater O2 extraction. Differences in lung and muscle diffusing capacity, and not hematocrit variation, accounted for essentially all interindividual variance in peak V̇o2.
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Affiliation(s)
- Cecilia Anza-Ramírez
- 1Facultad de Ciencias y Filosofía, Laboratorio de Fisiología Comparada/Laboratorio de Fisiología del Transporte de Oxígeno, Universidad Peruana Cayetano Heredia, Lima, Perú
| | - Wanjun Gu
- 2Division of Pulmonary, Critical Care, and Sleep Medicine, School of Medicine, University of California San Diego, La Jolla, California
| | - José L. Macarlupú
- 1Facultad de Ciencias y Filosofía, Laboratorio de Fisiología Comparada/Laboratorio de Fisiología del Transporte de Oxígeno, Universidad Peruana Cayetano Heredia, Lima, Perú
| | - Rómulo J. Figueroa-Mujíca
- 1Facultad de Ciencias y Filosofía, Laboratorio de Fisiología Comparada/Laboratorio de Fisiología del Transporte de Oxígeno, Universidad Peruana Cayetano Heredia, Lima, Perú
| | - Gustavo A. Vizcardo-Galindo
- 1Facultad de Ciencias y Filosofía, Laboratorio de Fisiología Comparada/Laboratorio de Fisiología del Transporte de Oxígeno, Universidad Peruana Cayetano Heredia, Lima, Perú
| | - Erica C. Heinrich
- 2Division of Pulmonary, Critical Care, and Sleep Medicine, School of Medicine, University of California San Diego, La Jolla, California,3Division of Biomedical Sciences, School of Medicine, University of California Riverside, Riverside, California
| | - Michael S. Tift
- 2Division of Pulmonary, Critical Care, and Sleep Medicine, School of Medicine, University of California San Diego, La Jolla, California,4Department of Biology and Marine Biology, University of North Carolina at Wilmington, Wilmington, North Carolina
| | - Harrieth E. Wagner
- 2Division of Pulmonary, Critical Care, and Sleep Medicine, School of Medicine, University of California San Diego, La Jolla, California
| | - Peter D. Wagner
- 2Division of Pulmonary, Critical Care, and Sleep Medicine, School of Medicine, University of California San Diego, La Jolla, California
| | - Tatum S. Simonson
- 2Division of Pulmonary, Critical Care, and Sleep Medicine, School of Medicine, University of California San Diego, La Jolla, California
| | - Francisco C. Villafuerte
- 1Facultad de Ciencias y Filosofía, Laboratorio de Fisiología Comparada/Laboratorio de Fisiología del Transporte de Oxígeno, Universidad Peruana Cayetano Heredia, Lima, Perú
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Zhu D, Zhang M, He B, Wan Y, Wang L, Gao F. The role of sex and ovarian hormones in hippocampal damage and cognitive deficits induced by chronic exposure to hypobaric hypoxia. Front Neurosci 2022; 16:953417. [PMID: 36003965 PMCID: PMC9393425 DOI: 10.3389/fnins.2022.953417] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Accepted: 07/15/2022] [Indexed: 11/13/2022] Open
Abstract
Purpose This study aims to investigate the role of sex and ovarian hormones in hippocampal damage and cognitive deficits and behavioral dysfunction in rats induced by chronic exposure to hypobaric hypoxia. Methods Six-week-old male and female SD rats were housed for 3 months either in a real altitude (4,250 m) environment as the model of chronic hypobaric-hypoxia (CHH) or in a plain as controls. The animal behavioral and hippocampal neurons at subcellular, molecular, and ultrastructural levels were characterized after CHH exposure. Results After 3 months of CHH exposure, (1) male CHH rats’ serum testosterone level was lower than male controls’ whereas female CHH rats’ serum estradiol level was higher than female controls’; (2) Morris water maze test finds that male rats showed more learning and spatial memory deficits than female rats; (3) male rats showed more severe hippocampal damage, hippocampal inflammation, oxidative stress and decreased hippocampal integrity (neurogenesis and dendritic spine density) than female rats; (4) Western blot analysis shows that, compared with the male control group, in male CHH group’s hippocampus, expression of nNOS, HO-1, and Bax protein increased whereas that of Bcl-2 protein decreased; (5) Expression of PON2 protein in male rats (CHH and controls) was lower than female rats (CHH and controls). In addition, CHH exposure decreased the expression of PON2 protein in both male and female rats; (6) qPCR analysis reveals that CHH exposure reduced the gene expression of N-methyl-D-aspartate receptor NR2A and NR2B subunits in male rats’ hippocampus. In addition, compared with the sham CHH group, the expression level of PON2 protein decreased in the OVX-CHH group’s hippocampus whereas oxidative stress, neuroinflammation, and degeneration of hippocampal neurons increased in the OVX-CHH group’s hippocampus. Conclusion After CHH exposure, male rats were significantly more likely than female rats to develop hippocampal damage, hippocampal neuroinflammation, and cognitive decline and deficits, suggesting that sex and ovarian hormones were significantly involved in regulating the rats’ susceptibility to CHH exposure-induced hippocampal damage.
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Villafuerte FC, Simonson TS, Bermudez D, León-Velarde F. High-Altitude Erythrocytosis: Mechanisms of Adaptive and Maladaptive Responses. Physiology (Bethesda) 2022; 37:0. [PMID: 35001654 PMCID: PMC9191173 DOI: 10.1152/physiol.00029.2021] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Erythrocytosis, or increased production of red blood cells, is one of the most well-documented physiological traits that varies within and among in high-altitude populations. Although a modest increase in blood O2-carrying capacity may be beneficial for life in highland environments, erythrocytosis can also become excessive and lead to maladaptive syndromes such as chronic mountain sickness (CMS).
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Affiliation(s)
- Francisco C. Villafuerte
- 1Laboratorio de Fisiología Comparada/Laboratorio de Fisiología del Transporte de Oxígeno, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Perú
| | - Tatum S. Simonson
- 2Division of Pulmonary, Critical Care, and Sleep Medicine, School of Medicine, University of California, San Diego, La Jolla, California
| | - Daniela Bermudez
- 1Laboratorio de Fisiología Comparada/Laboratorio de Fisiología del Transporte de Oxígeno, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Perú
| | - Fabiola León-Velarde
- 1Laboratorio de Fisiología Comparada/Laboratorio de Fisiología del Transporte de Oxígeno, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Perú
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Macarlupú JL, Vizcardo-Galindo G, Figueroa-Mujíca R, Voituron N, Richalet JP, Villafuerte FC. Sub-maximal aerobic exercise training reduces haematocrit and ameliorates symptoms in Andean highlanders with chronic mountain sickness. Exp Physiol 2021; 106:2198-2209. [PMID: 34555237 PMCID: PMC9293431 DOI: 10.1113/ep089975] [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: 08/05/2021] [Accepted: 09/16/2021] [Indexed: 12/27/2022]
Abstract
New Findings What is the central question of this study? What is the effect of sub‐maximal aerobic exercise training on signs and symptoms of chronic mountain sickness (CMS) in Andean highlanders? What is the main finding and its importance? Aerobic exercise training (ET) effectively reduces haematocrit, ameliorates symptoms and improves aerobic capacity in CMS patients, suggesting that a regular aerobic ET programme might be used as a low‐cost non‐invasive/non‐pharmacological management strategy of this syndrome.
Abstract Excessive erythrocytosis is the hallmark sign of chronic mountain sickness (CMS), a debilitating syndrome associated with neurological symptoms and increased cardiovascular risk. We have shown that unlike sedentary residents at the same altitude, trained individuals maintain haematocrit within sea‐level range, and thus we hypothesise that aerobic exercise training (ET) might reduce excessive haematocrit and ameliorate CMS signs and symptoms. Eight highlander men (38 ± 12 years) with CMS (haematocrit: 70.6 ± 1.9%, CMS score: 8.8 ± 1.4) from Cerro de Pasco, Peru (4340 m) participated in the study. Baseline assessment included haematocrit, CMS score, pulse oximetry, maximal cardiopulmonary exercise testing and in‐office plus 24 h ambulatory blood pressure (BP) monitoring. Blood samples were collected to assess cardiometabolic, erythropoietic, and haemolysis markers. ET consisted of pedalling exercise in a cycloergometer at 60% of V˙O2peak for 1 h/day, 4 days/week for 8 weeks, and participants were assessed at weeks 4 and 8. Haematocrit and CMS score decreased significantly by week 8 (to 65.6 ± 6.6%, and 3.5 ± 0.8, respectively, P < 0.05), while V˙O2peak and maximum workload increased with ET (33.8 ± 2.4 vs. 37.2 ± 2.0 ml/min/kg, P < 0.05; and 172.5 ± 9.4 vs. 210.0 ± 27.8 W, P < 0.01; respectively). Except for an increase in high‐density lipoprotein cholesterol, other blood markers and BP showed no differences. Our results suggest that reduction of haematocrit and CMS symptoms results mainly from haemodilution due to plasma volume expansion rather than to haemolysis. In conclusion, we show that ET can effectively reduce haematocrit, ameliorate symptoms and improve aerobic capacity in CMS patients, suggesting that regular aerobic exercise might be used as a low‐cost non‐invasive and non‐pharmacological management strategy.
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Affiliation(s)
- José Luis Macarlupú
- Laboratorio de Fisiología Comparada, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Perú.,Instituto de Investigaciones de la Altura (IIA), Universidad Peruana Cayetano Heredia, Lima, Perú
| | - Gustavo Vizcardo-Galindo
- Laboratorio de Fisiología Comparada, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Perú
| | - Rómulo Figueroa-Mujíca
- Laboratorio de Fisiología Comparada, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Perú
| | - Nicolas Voituron
- Laboratoire Hypoxie et Poumon, UMR INSERM U1272, Université Sorbonne Paris Nord, Bobigny, France.,Laboratory of Excellence GReX, Paris, France.,Département STAPS, Université Sorbonne Paris Nord, Bobigny, France
| | - Jean-Paul Richalet
- Laboratoire Hypoxie et Poumon, UMR INSERM U1272, Université Sorbonne Paris Nord, Bobigny, France.,Laboratory of Excellence GReX, Paris, France
| | - Francisco C Villafuerte
- Laboratorio de Fisiología Comparada, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Perú.,Instituto de Investigaciones de la Altura (IIA), Universidad Peruana Cayetano Heredia, Lima, Perú
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Pulmonary Hypertension in Acute and Chronic High Altitude Maladaptation Disorders. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph18041692. [PMID: 33578749 PMCID: PMC7916528 DOI: 10.3390/ijerph18041692] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 02/05/2021] [Accepted: 02/07/2021] [Indexed: 12/13/2022]
Abstract
Alveolar hypoxia is the most prominent feature of high altitude environment with well-known consequences for the cardio-pulmonary system, including development of pulmonary hypertension. Pulmonary hypertension due to an exaggerated hypoxic pulmonary vasoconstriction contributes to high altitude pulmonary edema (HAPE), a life-threatening disorder, occurring at high altitudes in non-acclimatized healthy individuals. Despite a strong physiologic rationale for using vasodilators for prevention and treatment of HAPE, no systematic studies of their efficacy have been conducted to date. Calcium-channel blockers are currently recommended for drug prophylaxis in high-risk individuals with a clear history of recurrent HAPE based on the extensive clinical experience with nifedipine in HAPE prevention in susceptible individuals. Chronic exposure to hypoxia induces pulmonary vascular remodeling and development of pulmonary hypertension, which places an increased pressure load on the right ventricle leading to right heart failure. Further, pulmonary hypertension along with excessive erythrocytosis may complicate chronic mountain sickness, another high altitude maladaptation disorder. Importantly, other causes than hypoxia may potentially underlie and/or contribute to pulmonary hypertension at high altitude, such as chronic heart and lung diseases, thrombotic or embolic diseases. Extensive clinical experience with drugs in patients with pulmonary arterial hypertension suggests their potential for treatment of high altitude pulmonary hypertension. Small studies have demonstrated their efficacy in reducing pulmonary artery pressure in high altitude residents. However, no drugs have been approved to date for the therapy of chronic high altitude pulmonary hypertension. This work provides a literature review on the role of pulmonary hypertension in the pathogenesis of acute and chronic high altitude maladaptation disorders and summarizes current knowledge regarding potential treatment options.
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Azad P, Villafuerte FC, Bermudez D, Patel G, Haddad GG. Protective role of estrogen against excessive erythrocytosis in Monge's disease. Exp Mol Med 2021; 53:125-135. [PMID: 33473144 PMCID: PMC8080600 DOI: 10.1038/s12276-020-00550-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 11/12/2020] [Accepted: 11/19/2020] [Indexed: 01/29/2023] Open
Abstract
Monge's disease (chronic mountain sickness (CMS)) is a maladaptive condition caused by chronic (years) exposure to high-altitude hypoxia. One of the defining features of CMS is excessive erythrocytosis with extremely high hematocrit levels. In the Andean population, CMS prevalence is vastly different between males and females, being rare in females. Furthermore, there is a sharp increase in CMS incidence in females after menopause. In this study, we assessed the role of sex hormones (testosterone, progesterone, and estrogen) in CMS and non-CMS cells using a well-characterized in vitro erythroid platform. While we found that there was a mild (nonsignificant) increase in RBC production with testosterone, we observed that estrogen, in physiologic concentrations, reduced sharply CD235a+ cells (glycophorin A; a marker of RBC), from 56% in the untreated CMS cells to 10% in the treated CMS cells, in a stage-specific and dose-responsive manner. At the molecular level, we determined that estrogen has a direct effect on GATA1, remarkably decreasing the messenger RNA (mRNA) and protein levels of GATA1 (p < 0.01) and its target genes (Alas2, BclxL, and Epor, p < 0.001). These changes result in a significant increase in apoptosis of erythroid cells. We also demonstrate that estrogen regulates erythropoiesis in CMS patients through estrogen beta signaling and that its inhibition can diminish the effects of estrogen by significantly increasing HIF1, VEGF, and GATA1 mRNA levels. Taken altogether, our results indicate that estrogen has a major impact on the regulation of erythropoiesis, particularly under chronic hypoxic conditions, and has the potential to treat blood diseases, such as high altitude severe erythrocytosis.
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Affiliation(s)
- Priti Azad
- Department of Pediatrics, Division of Respiratory Medicine, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Francisco C Villafuerte
- Laboratorio de Fisiologia del Transporte de Oxigeno/Fisiología Comparada, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, San Martin de Porres, Lima 31, Peru
| | - Daniela Bermudez
- Laboratorio de Fisiologia del Transporte de Oxigeno/Fisiología Comparada, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, San Martin de Porres, Lima 31, Peru
| | - Gargi Patel
- Department of Pediatrics, Division of Respiratory Medicine, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Gabriel G Haddad
- Department of Pediatrics, Division of Respiratory Medicine, University of California, San Diego, La Jolla, CA, 92093, USA.
- Department of Neurosciences, University of California, San Diego, La Jolla, CA, 92093, USA.
- Rady Children's Hospital, San Diego, CA, 92123, USA.
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Soliz J, Schneider-Gasser EM, Arias-Reyes C, Aliaga-Raduan F, Poma-Machicao L, Zubieta-Calleja G, Furuya WI, Trevizan-Baú P, Dhingra RR, Dutschmann M. Coping with hypoxemia: Could erythropoietin (EPO) be an adjuvant treatment of COVID-19? Respir Physiol Neurobiol 2020; 279:103476. [PMID: 32522574 PMCID: PMC7275159 DOI: 10.1016/j.resp.2020.103476] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 05/29/2020] [Accepted: 05/30/2020] [Indexed: 12/13/2022]
Abstract
A very recent epidemiological study provides preliminary evidence that living in habitats located at 2500 m above sea level (masl) might protect from the development of severe respiratory symptoms following infection with the novel SARS-CoV-2 virus. This epidemiological finding raises the question of whether physiological mechanisms underlying the acclimatization to high altitude identifies therapeutic targets for the effective treatment of severe acute respiratory syndrome pivotal to the reduction of global mortality during the COVID-19 pandemic. This article compares the symptoms of acute mountain sickness (AMS) with those of SARS-CoV-2 infection and explores overlapping patho-physiological mechanisms of the respiratory system including impaired oxygen transport, pulmonary gas exchange and brainstem circuits controlling respiration. In this context, we also discuss the potential impact of SARS-CoV-2 infection on oxygen sensing in the carotid body. Finally, since erythropoietin (EPO) is an effective prophylactic treatment for AMS, this article reviews the potential benefits of implementing FDA-approved erythropoietin-based (EPO) drug therapies to counteract a variety of acute respiratory and non-respiratory (e.g. excessive inflammation of vascular beds) symptoms of SARS-CoV-2 infection.
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Affiliation(s)
- Jorge Soliz
- Institute Universitaire de Cardiologie et de Pneumologie de Québec (IUCPQ), Faculty of Medicine, Université Laval, Québec, QC, Canada; High Altitude Pulmonary and Pathology Institute IPPA, La Paz, Bolivia.
| | - Edith M Schneider-Gasser
- Institute of Veterinary Physiology, Vetsuisse-Faculty University of Zurich, Winterthurerstrasse 260, Switzerland
| | - Christian Arias-Reyes
- Institute Universitaire de Cardiologie et de Pneumologie de Québec (IUCPQ), Faculty of Medicine, Université Laval, Québec, QC, Canada
| | - Fernanda Aliaga-Raduan
- Institute Universitaire de Cardiologie et de Pneumologie de Québec (IUCPQ), Faculty of Medicine, Université Laval, Québec, QC, Canada
| | - Liliana Poma-Machicao
- Institute Universitaire de Cardiologie et de Pneumologie de Québec (IUCPQ), Faculty of Medicine, Université Laval, Québec, QC, Canada
| | | | - Werner I Furuya
- Florey Institute of Neuroscience and Mental Health, Melbourne Victoria, Australia; The Florey Department of Neuroscience, University of Melbourne, Melbourne Victoria, Australia
| | - Pedro Trevizan-Baú
- Florey Institute of Neuroscience and Mental Health, Melbourne Victoria, Australia; The Florey Department of Neuroscience, University of Melbourne, Melbourne Victoria, Australia
| | - Rishi R Dhingra
- Florey Institute of Neuroscience and Mental Health, Melbourne Victoria, Australia
| | - Mathias Dutschmann
- Florey Institute of Neuroscience and Mental Health, Melbourne Victoria, Australia; The Florey Department of Neuroscience, University of Melbourne, Melbourne Victoria, Australia
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9
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Hancco I, Bailly S, Baillieul S, Doutreleau S, Germain M, Pépin JL, Verges S. Excessive Erythrocytosis and Chronic Mountain Sickness in Dwellers of the Highest City in the World. Front Physiol 2020; 11:773. [PMID: 32760289 PMCID: PMC7373800 DOI: 10.3389/fphys.2020.00773] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Accepted: 06/11/2020] [Indexed: 12/12/2022] Open
Abstract
Background While millions of people are living permanently at high altitude (>2,500 m) worldwide, the mechanisms underlying their tolerance to chronic hypoxia and those responsible for the occurrence of chronic mountain sickness (CMS) remain to be elucidated. Excessive erythrocytosis (EE) is thought to be the main mechanism responsible for CMS symptoms and is included in the definition of CMS, but the precise interplay between EE and symptoms of CMS requires further investigations. Methods The present study benefits from an exceptional dataset coming from 1,594 dwellers of La Rinconada, the highest city in the world (5,100-5,300 m). Based on individual clinical characteristics, subjects were categorized according to the presence of EE and CMS diagnosis, based on current guidelines. Results In this population of relatively young [32 (23; 39) years] highlanders residing in La Rinconada for only a few years [3 (2; 5) years], the internal prevalence of EE (44%) was high, whereas the internal prevalence of CMS (14%) was similar compared to previous reports in highlander populations living at lower altitude (∼4,000 m) in the Andes. Individuals with EE reported less symptoms compared to individuals with lower hematocrit values. Multivariable analysis revealed that age and sex are the main factors associated with EE, whereas age, hematocrit and number of years living at La Rinconada are factors associated with CMS symptoms. Conclusion In this specific population of La Rinconada, high hematocrit values were observed but were associated with limited symptoms. These results raise important questions regarding the definition of EE and CMS and their underlying mechanisms in high-altitude populations.
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Affiliation(s)
- Ivan Hancco
- HP2 Laboratory, Univ. Grenoble Alpes, INSERM, Grenoble Alpes University Hospital, Grenoble, France
| | - Sébastien Bailly
- HP2 Laboratory, Univ. Grenoble Alpes, INSERM, Grenoble Alpes University Hospital, Grenoble, France
| | - Sébastien Baillieul
- HP2 Laboratory, Univ. Grenoble Alpes, INSERM, Grenoble Alpes University Hospital, Grenoble, France
| | - Stéphane Doutreleau
- HP2 Laboratory, Univ. Grenoble Alpes, INSERM, Grenoble Alpes University Hospital, Grenoble, France
| | - Michèle Germain
- Laboratoire Interuniversitaire de Biologie de la Motricité (LIBM) EA7424, Team "Vascular Biology and Red Blood Cell", Université Claude Bernard Lyon 1, University of Lyon, Lyon, France
| | - Jean-Louis Pépin
- HP2 Laboratory, Univ. Grenoble Alpes, INSERM, Grenoble Alpes University Hospital, Grenoble, France
| | - Samuel Verges
- HP2 Laboratory, Univ. Grenoble Alpes, INSERM, Grenoble Alpes University Hospital, Grenoble, France
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10
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Heinrich EC, Orr JE, Gilbertson D, Anza-Ramirez C, DeYoung PN, Djokic MA, Corante N, Vizcardo-Galindo G, Macarlupu JL, Gaio E, Powell FL, Malhotra A, Villafuerte FC, Simonson TS. Relationships Between Chemoreflex Responses, Sleep Quality, and Hematocrit in Andean Men and Women. Front Physiol 2020; 11:437. [PMID: 32435207 PMCID: PMC7219107 DOI: 10.3389/fphys.2020.00437] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Accepted: 04/08/2020] [Indexed: 12/12/2022] Open
Abstract
Andean highlanders are challenged by chronic hypoxia and many exhibit elevated hematocrit (Hct) and blunted ventilation compared to other high-altitude populations. While many Andeans develop Chronic Mountain Sickness (CMS) and excessive erythrocytosis, Hct varies markedly within Andean men and women and may be driven by individual differences in ventilatory control and/or sleep events which exacerbate hypoxemia. To test this hypothesis, we quantified relationships between resting ventilation and ventilatory chemoreflexes, sleep desaturation, breathing disturbance, and Hct in Andean men and women. Ventilatory measures were made in 109 individuals (n = 63 men; n = 46 women), and sleep measures in 45 of these participants (n = 22 men; n = 23 women). In both men and women, high Hct was associated with low daytime SpO2 (p < 0.001 and p < 0.002, respectively) and decreased sleep SpO2 (mean, nadir, and time <80%; all p < 0.02). In men, high Hct was also associated with increased end-tidal PCO2 (p < 0.009). While ventilatory responses to hypoxia and hypercapnia did not predict Hct, decreased hypoxic ventilatory responses were associated with lower daytime SpO2 in men (p < 0.01) and women (p < 0.009) and with lower nadir sleep SpO2 in women (p < 0.02). Decreased ventilatory responses to CO2 were associated with more time below 80% SpO2 during sleep in men (p < 0.05). The obstructive apnea index and apnea-hypopnea index also predicted Hct and CMS scores in men after accounting for age, BMI, and SpO2 during sleep. Finally, heart rate response to hypoxia was lower in men with higher Hct (p < 0.0001). These data support the idea that hypoventilation and decreased ventilatory sensitivity to hypoxia are associated with decreased day time and nighttime SpO2 levels that may exacerbate the stimulus for erythropoiesis in Andean men and women. However, interventional and longitudinal studies are required to establish the causal relationships between these associations.
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Affiliation(s)
- Erica C Heinrich
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, University of California, San Diego, San Diego, CA, United States
| | - Jeremy E Orr
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, University of California, San Diego, San Diego, CA, United States
| | - Dillon Gilbertson
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, University of California, San Diego, San Diego, CA, United States
| | - Cecilia Anza-Ramirez
- Laboratorio de Fisiología Comparada/Fisiología del Transporte de Oxígen, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Pamela N DeYoung
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, University of California, San Diego, San Diego, CA, United States
| | - Matea A Djokic
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, University of California, San Diego, San Diego, CA, United States
| | - Noemi Corante
- Laboratorio de Fisiología Comparada/Fisiología del Transporte de Oxígen, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Gustavo Vizcardo-Galindo
- Laboratorio de Fisiología Comparada/Fisiología del Transporte de Oxígen, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Jose L Macarlupu
- Laboratorio de Fisiología Comparada/Fisiología del Transporte de Oxígen, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Eduardo Gaio
- Faculty of Medicine, University of Brasília, Brasília, Brazil
| | - Frank L Powell
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, University of California, San Diego, San Diego, CA, United States
| | - Atul Malhotra
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, University of California, San Diego, San Diego, CA, United States
| | - Francisco C Villafuerte
- Laboratorio de Fisiología Comparada/Fisiología del Transporte de Oxígen, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Tatum S Simonson
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, University of California, San Diego, San Diego, CA, United States
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11
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Human Genetic Adaptation to High Altitude: Evidence from the Andes. Genes (Basel) 2019; 10:genes10020150. [PMID: 30781443 PMCID: PMC6410003 DOI: 10.3390/genes10020150] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Revised: 01/29/2019] [Accepted: 02/11/2019] [Indexed: 12/31/2022] Open
Abstract
Whether Andean populations are genetically adapted to high altitudes has long been of interest. Initial studies focused on physiological changes in the O₂ transport system that occur with acclimatization in newcomers and their comparison with those of long-resident Andeans. These as well as more recent studies indicate that Andeans have somewhat larger lung volumes, narrower alveolar to arterial O₂ gradients, slightly less hypoxic pulmonary vasoconstrictor response, greater uterine artery blood flow during pregnancy, and increased cardiac O2 utilization, which overall suggests greater efficiency of O₂ transfer and utilization. More recent single nucleotide polymorphism and whole-genome sequencing studies indicate that multiple gene regions have undergone recent positive selection in Andeans. These include genes involved in the regulation of vascular control, metabolic hemostasis, and erythropoiesis. However, fundamental questions remain regarding the functional links between these adaptive genomic signals and the unique physiological attributes of highland Andeans. Well-designed physiological and genome association studies are needed to address such questions. It will be especially important to incorporate the role of epigenetic processes (i.e.; non-sequence-based features of the genome) that are vital for transcriptional responses to hypoxia and are potentially heritable across generations. In short, further exploration of the interaction among genetic, epigenetic, and environmental factors in shaping patterns of adaptation to high altitude promises to improve the understanding of the mechanisms underlying human adaptive potential and clarify its implications for human health.
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12
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Moore LG. Measuring high-altitude adaptation. J Appl Physiol (1985) 2017; 123:1371-1385. [PMID: 28860167 DOI: 10.1152/japplphysiol.00321.2017] [Citation(s) in RCA: 105] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Revised: 08/15/2017] [Accepted: 08/15/2017] [Indexed: 12/12/2022] Open
Abstract
High altitudes (>8,000 ft or 2,500 m) provide an experiment of nature for measuring adaptation and the physiological processes involved. Studies conducted over the past ~25 years in Andeans, Tibetans, and, less often, Ethiopians show varied but distinct O2 transport traits from those of acclimatized newcomers, providing indirect evidence for genetic adaptation to high altitude. Short-term (acclimatization, developmental) and long-term (genetic) responses to high altitude exhibit a temporal gradient such that, although all influence O2 content, the latter also improve O2 delivery and metabolism. Much has been learned concerning the underlying physiological processes, but additional studies are needed on the regulation of blood flow and O2 utilization. Direct evidence of genetic adaptation comes from single-nucleotide polymorphism (SNP)-based genome scans and whole genome sequencing studies that have identified gene regions acted upon by natural selection. Efforts have begun to understand the connections between the two with Andean studies on the genetic factors raising uterine blood flow, fetal growth, and susceptibility to Chronic Mountain Sickness and Tibetan studies on genes serving to lower hemoglobin and pulmonary arterial pressure. Critical for future studies will be the selection of phenotypes with demonstrable effects on reproductive success, the calculation of actual fitness costs, and greater inclusion of women among the subjects being studied. The well-characterized nature of the O2 transport system, the presence of multiple long-resident populations, and relevance for understanding hypoxic disorders in all persons underscore the importance of understanding how evolutionary adaptation to high altitude has occurred.NEW & NOTEWORTHY Variation in O2 transport characteristics among Andean, Tibetan, and, when available, Ethiopian high-altitude residents supports the existence of genetic adaptations that improve the distribution of blood flow to vital organs and the efficiency of O2 utilization. Genome scans and whole genome sequencing studies implicate a broad range of gene regions. Future studies are needed using phenotypes of clear relevance for reproductive success for determining the mechanisms by which naturally selected genes are acting.
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Affiliation(s)
- Lorna G Moore
- Division of Reproductive Sciences, Department of Obstetrics & Gynecology, University of Colorado Denver-Anschutz Medical Campus, Aurora, Colorado
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13
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Villafuerte FC, Corante N. Chronic Mountain Sickness: Clinical Aspects, Etiology, Management, and Treatment. High Alt Med Biol 2016; 17:61-9. [PMID: 27218284 PMCID: PMC4913504 DOI: 10.1089/ham.2016.0031] [Citation(s) in RCA: 120] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Villafuerte, Francisco C., and Noemí Corante. Chronic mountain sickness: clinical aspects, etiology, management, and treatment. High Alt Med Biol. 17:61–69, 2016.—Millions of people worldwide live at a high altitude, and a significant number are at risk of developing Chronic Mountain Sickness (CMS), a progressive incapacitating syndrome caused by lifelong exposure to hypoxia. CMS is characterized by severe symptomatic excessive erythrocytosis (EE; Hb ≥19 g/dL for women and Hb ≥21 g/dL for men) and accentuated hypoxemia, which are frequently associated with pulmonary hypertension. In advanced cases, the condition may evolve to cor pulmonale and congestive heart failure. Current knowledge indicates a genetic predisposition to develop CMS. However, there are important risk factors and comorbidities that may trigger and aggravate the condition. Thus, appropriate medical information on CMS is necessary to provide adequate diagnosis and healthcare to high-altitude inhabitants. After reviewing basic clinical aspects of CMS, including its definition, diagnosis, and common clinical findings, we discuss aspects of its etiology, and address its epidemiology, risk factors, and treatment.
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Affiliation(s)
- Francisco C Villafuerte
- Laboratorio de Fisiología Comparada, Departamento de Ciencias Biológicas y Fisiológicas, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia , Lima, Perú
| | - Noemí Corante
- Laboratorio de Fisiología Comparada, Departamento de Ciencias Biológicas y Fisiológicas, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia , Lima, Perú
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14
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Villafuerte FC, Corante N, Anza-Ramírez C, Figueroa-Mujíca R, Vizcardo-Galindo G, Mercado A, Macarlupú JL, León-Velarde F. Plasma soluble erythropoietin receptor is decreased during sleep in Andean highlanders with Chronic Mountain Sickness. J Appl Physiol (1985) 2016; 121:53-8. [PMID: 27125843 PMCID: PMC4967249 DOI: 10.1152/japplphysiol.00107.2016] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 04/27/2016] [Indexed: 12/24/2022] Open
Abstract
Andean highlanders suffering from Chronic Mountain Sickness (CMS) show consistently lower levels of plasma soluble erythropoietin (Epo) receptor (sEpoR) and higher Epo-to-EpoR ratios (Epo/sEpoR) during sleep compared with their healthy counterparts. This indicates higher blood Epo availability in CMS patients and continuous nocturnal erythropoietic stimulus. Additionally, morning Epo/sEpoR and mean sleep-time SpO2 are independent main predictors of Hct. These findings support the role of the Epo system in the development of excessive erythrocytosis in CMS. Excessive erythrocytosis (EE) is the main sign of Chronic Mountain Sickness (CMS), a highly prevalent syndrome in Andean highlanders. Low pulse O2 saturation (SpO2) during sleep and serum androgens have been suggested to contribute to EE in CMS patients. However, whether these factors have a significant impact on the erythropoietin (Epo) system leading to EE is still unclear. We have recently shown that morning soluble Epo receptor (sEpoR), an endogenous Epo antagonist, is decreased in CMS patients suggesting increased Epo availability (increased Epo/sEpoR). The present study aimed to characterize the nocturnal concentration profile of sEpoR and Epo and their relationship with SpO2, Hct, and serum testosterone in healthy highlanders (HH) and CMS patients. Epo and sEpoR concentrations were evaluated every 4 h (6 PM to 6 AM) and nighttime SpO2 was continuously monitored (10 PM to 6 AM) in 39 male participants (CMS, n = 23; HH, n = 16) aged 21-65 yr from Cerro de Pasco, Peru (4,340 m). CMS patients showed higher serum Epo concentrations throughout the night and lower sEpoR from 10 PM to 6 AM. Consequently, Epo/sEpoR was significantly higher in the CMS group at every time point. Mean sleep-time SpO2 was lower in CMS patients compared with HH, while the percentage of sleep time spent with SpO2 < 80% was higher. Multiple-regression analysis showed mean sleep-time SpO2 and Epo/sEpoR as significant predictors of hematocrit corrected for potential confounders (age, body mass index, and testosterone). Testosterone levels were associated neither with Hct nor with erythropoietic factors. In conclusion, our results show sustained erythropoietic stimulus driven by the Epo system in CMS patients, further enhanced by a continuous exposure to accentuated nocturnal hypoxemia.
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Affiliation(s)
- Francisco C Villafuerte
- Laboratorio de Fisiología Comparada, Departamento de Ciencias Biológicas y Fisiológicas, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Noemí Corante
- Laboratorio de Fisiología Comparada, Departamento de Ciencias Biológicas y Fisiológicas, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Cecilia Anza-Ramírez
- Laboratorio de Fisiología Comparada, Departamento de Ciencias Biológicas y Fisiológicas, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Rómulo Figueroa-Mujíca
- Laboratorio de Fisiología Comparada, Departamento de Ciencias Biológicas y Fisiológicas, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Gustavo Vizcardo-Galindo
- Laboratorio de Fisiología Comparada, Departamento de Ciencias Biológicas y Fisiológicas, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Andy Mercado
- Laboratorio de Fisiología Comparada, Departamento de Ciencias Biológicas y Fisiológicas, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - José Luis Macarlupú
- Laboratorio de Fisiología Comparada, Departamento de Ciencias Biológicas y Fisiológicas, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Fabiola León-Velarde
- Laboratorio de Fisiología Comparada, Departamento de Ciencias Biológicas y Fisiológicas, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
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Yan Y, Wang C, Zhou W, Shi Y, Guo P, Liu Y, Wang J, Zhang CY, Zhang C. Elevation of Circulating miR-210-3p in High-Altitude Hypoxic Environment. Front Physiol 2016; 7:84. [PMID: 27014085 PMCID: PMC4781857 DOI: 10.3389/fphys.2016.00084] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Accepted: 02/22/2016] [Indexed: 12/16/2022] Open
Abstract
Background: The induction of miR-210-3p, a master hypoxamir, is a consistent feature of the hypoxic response in both normal and malignant cells. However, whether miR-210-3p acts as a circulating factor in response to a hypoxic environment remains unknown. The current study aimed to examine the effect of a high-altitude hypoxic environment on circulating miR-210-3p. Methods: We examined and compared the levels of miR-210-3p using TaqMan-based qRT-PCR in both peripheral blood cells and plasma from 84 ethnic Chinese Tibetans residing at 3560 m, 46 newly arrived migrant Han Chinese (Tibet Han) and 82 Han Chinese residing at 8.9 m (Nanjing Han). Furthermore, we analyzed the correlations of miR-210-3p with hematological indices. Results: The relative concentrations of miR-210-3p to internal reference U6 in blood cells were significantly higher in the Tibet Han group (1.01 ± 0.11, P < 0.001) and in the Tibetan group (1.17 ± 0.09, P < 0.001) than in the Nanjing Han group (0.51 ± 0.04). The absolute concentrations of plasma miR-210-3p were also markedly elevated in the Tibet Han group (503.54 ± 42.95 fmol/L, P = 0.004) and in the Tibetan group (557.78 ± 39.84 fmol/L, P < 0.001) compared to the Nanjing Han group (358.39 ± 16.16 fmol/L). However, in both blood cells and plasma, miR-210-3p levels were not significantly different between the Tibet Han group and the Tibetan group (P = 0.280, P = 0.620, respectively). Plasma miR-210-3p concentrations were positively correlated with miR-210-3p levels in blood cells (r = 0.192, P = 0.005). Furthermore, miR-210-3p levels in both blood cells and plasma showed strong positive correlations with red blood cell counts and hemoglobin and hematocrit values. Conclusion: These data demonstrated, for the first time, that miR-210-3p might act as a circulating factor in response to hypoxic environments and could be associated with human adaptation to life at high altitudes.
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Affiliation(s)
- Yan Yan
- Department of Clinical Laboratory, Jinling Hospital, State Key Laboratory of Analytical Chemistry for Life Science, Jiangsu Engineering Research Center for MicroRNA Biology and Biotechnology, Nanjing University School of Medicine, Nanjing UniversityNanjing, China; State Key Laboratory of Pharmaceutical Biotechnology, Collaborative Innovation Center of Chemistry for Life Sciences, Jiangsu Engineering Research Center for MicroRNA Biology and Biotechnology, NJU Advanced Institute for Life Sciences, School of Life Sciences, Nanjing UniversityNanjing, China
| | - Cheng Wang
- Department of Clinical Laboratory, Jinling Hospital, State Key Laboratory of Analytical Chemistry for Life Science, Jiangsu Engineering Research Center for MicroRNA Biology and Biotechnology, Nanjing University School of Medicine, Nanjing UniversityNanjing, China; State Key Laboratory of Pharmaceutical Biotechnology, Collaborative Innovation Center of Chemistry for Life Sciences, Jiangsu Engineering Research Center for MicroRNA Biology and Biotechnology, NJU Advanced Institute for Life Sciences, School of Life Sciences, Nanjing UniversityNanjing, China
| | - Wanqing Zhou
- Department of Clinical Laboratory, The Affiliated Hospital of Nanjing University Medical School, Nanjing Drum Tower Hospital, Nanjing University Nanjing, China
| | - Yonghui Shi
- Department of Clinical Laboratory, Jinling Hospital, State Key Laboratory of Analytical Chemistry for Life Science, Jiangsu Engineering Research Center for MicroRNA Biology and Biotechnology, Nanjing University School of Medicine, Nanjing University Nanjing, China
| | - Pengtao Guo
- Department of Clinical Laboratory, The Forty-First Hospital of PLA Nêdong, China
| | - Yuxiu Liu
- Department of Medical Statistics, Nanjing University School of Medicine, Jinling Hospital, Nanjing University Nanjing, China
| | - Junjun Wang
- Department of Clinical Laboratory, Jinling Hospital, State Key Laboratory of Analytical Chemistry for Life Science, Jiangsu Engineering Research Center for MicroRNA Biology and Biotechnology, Nanjing University School of Medicine, Nanjing University Nanjing, China
| | - Chen-Yu Zhang
- State Key Laboratory of Pharmaceutical Biotechnology, Collaborative Innovation Center of Chemistry for Life Sciences, Jiangsu Engineering Research Center for MicroRNA Biology and Biotechnology, NJU Advanced Institute for Life Sciences, School of Life Sciences, Nanjing University Nanjing, China
| | - Chunni Zhang
- Department of Clinical Laboratory, Jinling Hospital, State Key Laboratory of Analytical Chemistry for Life Science, Jiangsu Engineering Research Center for MicroRNA Biology and Biotechnology, Nanjing University School of Medicine, Nanjing UniversityNanjing, China; State Key Laboratory of Pharmaceutical Biotechnology, Collaborative Innovation Center of Chemistry for Life Sciences, Jiangsu Engineering Research Center for MicroRNA Biology and Biotechnology, NJU Advanced Institute for Life Sciences, School of Life Sciences, Nanjing UniversityNanjing, China
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Okumiya K, Sakamoto R, Ishimoto Y, Kimura Y, Fukutomi E, Ishikawa M, Suwa K, Imai H, Chen W, Kato E, Nakatsuka M, Kasahara Y, Fujisawa M, Wada T, Wang H, Dai Q, Xu H, Qiao H, Ge RL, Norboo T, Tsering N, Kosaka Y, Nose M, Yamaguchi T, Tsukihara T, Ando K, Inamura T, Takeda S, Ishine M, Otsuka K, Matsubayashi K. Glucose intolerance associated with hypoxia in people living at high altitudes in the Tibetan highland. BMJ Open 2016; 6:e009728. [PMID: 26908520 PMCID: PMC4769430 DOI: 10.1136/bmjopen-2015-009728] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
OBJECTIVES To clarify the association between glucose intolerance and high altitudes (2900-4800 m) in a hypoxic environment in Tibetan highlanders and to verify the hypothesis that high altitude dwelling increases vulnerability to diabetes mellitus (DM) accelerated by lifestyle change or ageing. DESIGN Cross-sectional epidemiological study on Tibetan highlanders. PARTICIPANTS We enrolled 1258 participants aged 40-87 years. The rural population comprised farmers in Domkhar (altitude 2900-3800 m) and nomads in Haiyan (3000-3100 m), Ryuho (4400 m) and Changthang (4300-4800 m). Urban area participants were from Leh (3300 m) and Jiegu (3700 m). MAIN OUTCOME MEASURE Participants were classified into six glucose tolerance-based groups: DM, intermediate hyperglycaemia (IHG), normoglycaemia (NG), fasting DM, fasting IHG and fasting NG. Prevalence of glucose intolerance was compared in farmers, nomads and urban dwellers. Effects of dwelling at high altitude or hypoxia on glucose intolerance were analysed with the confounding factors of age, sex, obesity, lipids, haemoglobin, hypertension and lifestyle, using multiple logistic regression. RESULTS The prevalence of DM (fasting DM)/IHG (fasting IHG) was 8.9% (6.5%)/25.1% (12.7%), respectively, in all participants. This prevalence was higher in urban dwellers (9.5% (7.1%)/28.5% (11.7%)) and in farmers (8.5% (6.1%)/28.5% (18.3%)) compared with nomads (8.2% (5.7%)/15.7% (9.7%)) (p=0.0140/0.0001). Dwelling at high altitude was significantly associated with fasting IHG+fasting DM/fasting DM (ORs for >4500 and 3500-4499 m were 3.59/4.36 and 2.07/1.76 vs <3500 m, respectively). After adjusting for lifestyle change, hypoxaemia and polycythaemia were closely associated with glucose intolerance. CONCLUSIONS Socioeconomic factors, hypoxaemia and the effects of altitudes >3500 m play a major role in the high prevalence of glucose intolerance in highlanders. Tibetan highlanders may be vulnerable to glucose intolerance, with polycythaemia as a sign of poor hypoxic adaptation, accelerated by lifestyle change and ageing.
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Affiliation(s)
- Kiyohito Okumiya
- Research Department, Research Institute for Humanity and Nature, Kyoto, Japan
- Center for Southeast Asian Studies, Kyoto University, Kyoto, Japan
| | - Ryota Sakamoto
- Center for Southeast Asian Studies, Kyoto University, Kyoto, Japan
- Hakubi Center for Advanced Research, Kyoto University, Kyoto, Japan
| | - Yasuko Ishimoto
- Faculty of Medicine, Public Health Nursing, School of Nursing, Mie University, Tsu, Mie, Japan
| | - Yumi Kimura
- Center for Southeast Asian Studies, Kyoto University, Kyoto, Japan
| | - Eriko Fukutomi
- Center for Southeast Asian Studies, Kyoto University, Kyoto, Japan
| | - Motonao Ishikawa
- Department of Medicine, Tokyo Women's Medical University, Medical Center East, Tokyo, Japan
| | - Kuniaki Suwa
- Department of Medicine, Tokyo Women's Medical University, Medical Center East, Tokyo, Japan
| | - Hissei Imai
- Health Promotion and Human Behavior, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Wenling Chen
- Center for Southeast Asian Studies, Kyoto University, Kyoto, Japan
| | - Emiko Kato
- Center for Southeast Asian Studies, Kyoto University, Kyoto, Japan
| | | | - Yoriko Kasahara
- College of Nursing, Kanto Gakuin University, Yokohama, Japan
| | - Michiko Fujisawa
- Center for Southeast Asian Studies, Kyoto University, Kyoto, Japan
| | - Taizo Wada
- Center for Southeast Asian Studies, Kyoto University, Kyoto, Japan
| | - Hongxin Wang
- Affiliated Hospital of Qinghai University, Xining, Qinghai, China
| | - Qingxiang Dai
- Affiliated Hospital of Qinghai University, Xining, Qinghai, China
| | - Huining Xu
- Affiliated Hospital of Qinghai University, Xining, Qinghai, China
| | - Haisheng Qiao
- Qinghai Academy of Animal and Veterinary Sciences, Xining, Qinghai, China
| | - Ri-Li Ge
- Research Center for High Altitude Medicine, Qinghai University, Xining, Qinghai, China
| | | | | | - Yasuyuki Kosaka
- Graduate School of Asian and African Area Studies, Kyoto University, Kyoto, Japan
| | - Mitsuhiro Nose
- Center for Southeast Asian Studies, Kyoto University, Kyoto, Japan
| | | | - Toshihiro Tsukihara
- Faculty of Education and Regional Studies, University of Fukui, Fukui, Japan
| | - Kazuo Ando
- Center for Southeast Asian Studies, Kyoto University, Kyoto, Japan
| | | | - Shinya Takeda
- Graduate School of Asian and African Area Studies, Kyoto University, Kyoto, Japan
| | | | - Kuniaki Otsuka
- Department of Medicine, Tokyo Women's Medical University, Medical Center East, Tokyo, Japan
- Chronomics & Gerontology, Tokyo Women's Medical University, Tokyo, Japan
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Mirrakhimov AE, Strohl KP. High-altitude Pulmonary Hypertension: an Update on Disease Pathogenesis and Management. Open Cardiovasc Med J 2016; 10:19-27. [PMID: 27014374 PMCID: PMC4780514 DOI: 10.2174/1874192401610010019] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2015] [Revised: 09/20/2015] [Accepted: 10/22/2015] [Indexed: 12/18/2022] Open
Abstract
High-altitude pulmonary hypertension (HAPH) affects individuals residing at altitudes of 2,500 meters and higher. Numerous pathogenic variables play a role in disease inception and progression and include low oxygen concentration in inspired air, vasculopathy, and metabolic abnormalities. Since HAPH affects only some people living at high altitude genetic factors play a significant role in its pathogenesis. The clinical presentation of HAPH is nonspecific and includes fatigue, shortness of breath, cognitive deficits, cough, and in advanced cases hepatosplenomegaly and overt right-sided heart failure. A thorough history is important and should include a search for additional risk factors for lung disease and pulmonary hypertension (PH) such as smoking, indoor air pollution, left-sided cardiac disease and sleep disordered breathing. Twelve-lead electrocardiogram, chest X-ray and echocardiography can be used as screening tools. A definitive diagnosis should be made with right-sided heart catheterization using a modified mean pulmonary artery pressure of at least 30 mm Hg, differing from the 25 mm Hg used for other types of PH. Treatment of HAPH includes descent to a lower altitude whenever possible, oxygen therapy and the use of medications such as endothelin receptor antagonists, phosphodiesterase 5 blockers, fasudil and acetazolamide. Some recent evidence suggests that iron supplementation may also be beneficial. However, it is important to note that the scientific literature lacks long-term randomized controlled data on the pharmacologic treatment of HAPH. Thus, an individualized approach to treatment and informing the patients regarding the benefits and risks of the selected treatment regimen are essential.
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Affiliation(s)
- Aibek E Mirrakhimov
- University of Kentucky College of Medicine, Department of Medicine, Lexington, Kentucky, 40508, USA
| | - Kingman P Strohl
- Case Western Reserve University, Division of Pulmonary, Critical Care and Sleep Medicine, 11100 Euclid Ave, Cleve-land, Ohio 44106, USA
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18
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Julian CG, Gonzales M, Rodriguez A, Bellido D, Salmon CS, Ladenburger A, Reardon L, Vargas E, Moore LG. Perinatal hypoxia increases susceptibility to high-altitude polycythemia and attendant pulmonary vascular dysfunction. Am J Physiol Heart Circ Physiol 2015; 309:H565-73. [PMID: 26092986 DOI: 10.1152/ajpheart.00296.2015] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Accepted: 06/17/2015] [Indexed: 12/22/2022]
Abstract
Perinatal exposures exert a profound influence on physiological function, including developmental processes vital for efficient pulmonary gas transfer throughout the lifespan. We extend the concept of developmental programming to chronic mountain sickness (CMS), a debilitating syndrome marked by polycythemia, ventilatory impairment, and pulmonary hypertension that affects ∼10% of male high-altitude residents. We hypothesized that adverse perinatal oxygenation caused abnormalities of ventilatory and/or pulmonary vascular function that increased susceptibility to CMS in adulthood. Subjects were 67 male high-altitude (3,600-4,100 m) residents aged 18-25 yr with excessive erythrocytosis (EE, Hb concentration ≥18.3 g/dl), a preclinical form of CMS, and 66 controls identified from a community-based survey (n = 981). EE subjects not only had higher Hb concentrations and erythrocyte counts, but also lower alveolar ventilation, impaired pulmonary diffusion capacity, higher systolic pulmonary artery pressure, lower pulmonary artery acceleration time, and more frequent right ventricular hypertrophy, than controls. Compared with controls, EE subjects were more often born to mothers experiencing hypertensive complications of pregnancy and hypoxia during the perinatal period, with each increasing the risk of developing EE (odds ratio = 5.25, P = 0.05 and odds ratio = 6.44, P = 0.04, respectively) after other factors known to influence EE status were taken into account. Adverse perinatal oxygenation is associated with increased susceptibility to EE accompanied by modest abnormalities of the pulmonary circulation that are independent of increased blood viscosity. The association between perinatal hypoxia and EE may be due to disrupted alveolarization and microvascular development, leading to impaired gas exchange and/or pulmonary hypertension.
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Affiliation(s)
- Colleen Glyde Julian
- Department of Medicine, University of Colorado School of Medicine, Aurora, Colorado;
| | | | | | - Diva Bellido
- Bolivian Institute of High Altitude Biology, La Paz, Bolivia
| | | | - Anne Ladenburger
- Department of Obstetrics and Gynecology, University of Utah, Salt Lake City, Utah
| | - Lindsay Reardon
- Department of Emergency Medicine, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire; and
| | - Enrique Vargas
- Bolivian Institute of High Altitude Biology, La Paz, Bolivia
| | - Lorna G Moore
- Department of Obstetrics and Gynecology, University of Colorado School of Medicine, Aurora, Colorado
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19
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Niermeyer S, Andrade-M MP, Vargas E, Moore LG. Neonatal oxygenation, pulmonary hypertension, and evolutionary adaptation to high altitude (2013 Grover Conference series). Pulm Circ 2015; 5:48-62. [PMID: 25992270 PMCID: PMC4405714 DOI: 10.1086/679719] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Accepted: 11/21/2014] [Indexed: 01/30/2023] Open
Abstract
Andeans and Tibetans have less altitude reduction in birth weight than do shorter-resident groups, but only Tibetans are protected from pulmonary hypertension and chronic mountain sickness (CMS). We hypothesized that differences in neonatal oxygenation were involved, with arterial O2 saturation (SaO2) being highest in Tibetans, intermediate in Andeans, and lowest in Han or Europeans, and that improved oxygenation in Andeans relative to Europeans was accompanied by a greater postnatal decline in systolic pulmonary arterial pressures (Ppasys ). We studied 41 healthy (36 Andeans, 5 Europeans) and 9 sick infants at 3,600 m in Bolivia. The SaO2 in healthy babies was highest at 6-24 hours of postnatal age and then declined, whereas sick babies showed the opposite pattern. Compared to that of 30 Tibetan or Han infants studied previously at 3,600 m, SaO2 was higher in Tibetans than in Han or Andeans during wakefulness and active or quiet sleep. Tibetans, as well as Andeans, had higher values than Han while feeding. The SaO2's of healthy Andeans and Europeans were similar and, like those of Tibetans, remained at 85% or above, whereas Han values dipped below 70%. Andean and European Ppasys values were above sea-level norms and higher in sick than in healthy babies, but right heart pressure decreased across 4-6 months in all groups. We concluded that Tibetans had better neonatal oxygenation than Andeans at 3,600 m but that, counter to our hypothesis, neither was SaO2 higher nor Ppa lower in Andean than in European infants. Further, longitudinal studies in these 4 groups are warranted to determine whether neonatal oxygenation influences susceptibility to high-altitude pulmonary hypertension and CMS later in life.
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Affiliation(s)
- Susan Niermeyer
- Department of Pediatrics, University of Colorado Denver, Aurora, Colorado, USA
| | - Mario Patricio Andrade-M
- Division of Cardiology (Pediatrics), Caja Nacional de Salud and Clínica del Sur, La Paz, Bolivia
| | - Enrique Vargas
- Department of Respiratory Medicine, Cardiology, and Physiology, Instituto Boliviano de Biología de Altura, La Paz, Bolivia
| | - Lorna G. Moore
- Department of Obstetrics and Gynecology and Center for Women’s Health Research, University of Colorado Denver, Aurora, Colorado, USA
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20
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De Ferrari A, Miranda JJ, Gilman RH, Dávila-Román VG, León-Velarde F, Rivera-Ch M, Huicho L, Bernabé-Ortiz A, Wise RA, Checkley W. Prevalence, clinical profile, iron status, and subject-specific traits for excessive erythrocytosis in andean adults living permanently at 3,825 meters above sea level. Chest 2015; 146:1327-1336. [PMID: 24874587 DOI: 10.1378/chest.14-0298] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
BACKGROUND Excessive erythrocytosis (EE) is a prevalent condition in populations living at high altitudes (> 2,500 m above sea level). Few large population-based studies have explored the association between EE and multiple subject-specific traits including oxygen saturation, iron status indicators, and pulmonary function. METHODS We enrolled a sex-stratified and age-stratified sample of 1,065 high-altitude residents aged ≥ 35 years from Puno, Peru (3,825 m above sea level) and conducted a standardized questionnaire and physical examination that included spirometry, pulse oximetry, and a blood sample for multiple clinical markers. Our primary objectives were to estimate the prevalence of EE, characterize the clinical profile and iron status indicators of subjects with EE, and describe subject-specific traits associated with EE. RESULTS Overall prevalence of EE was 4.5% (95% CI, 3.3%-6.0%). Oxygen saturation was significantly lower among EE than non-EE group subjects (85.3% vs 90.1%, P < .001) but no difference was found in iron status indicators between both groups (P > .09 for all values). In multivariable logistic regression, we found that age ≥ 65 years (OR = 2.45, 95% CI, 1.16-5.09), male sex (3.86, 1.78-9.08), having metabolic syndrome (2.66, 1.27-5.75) or being overweight (5.20, 1.95-16.77), pulse oximetry < 85% (14.90, 6.43-34.90), and % predicted FVC < 80% (13.62, 4.40-41.80) were strongly associated with EE. Attributable fractions for EE were greatest for being overweight (26.7%), followed by male sex (21.5%), pulse oximetry < 85% (16.4%), having metabolic syndrome (14.4%), and % predicted FVC < 80% (9.3%). CONCLUSIONS We found a lower prevalence of EE than in previous reports in the Peruvian Andes. Although the presence of hypoxemia and decreased vital capacity were strongly associated with excessive erythrocytosis, being overweight or having metabolic syndrome were associated with an important fraction of cases in our study population.
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Affiliation(s)
- Aldo De Ferrari
- From the Division of Pulmonary and Critical Care, School of Medicine, Johns Hopkins University, Baltimore, MD
| | - J Jaime Miranda
- CRONICAS Centre of Excellence for Chronic Diseases, Universidad Peruana Cayetano Heredia, Lima, Peru; Departamento de Medicina, Escuela de Medicina, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Robert H Gilman
- CRONICAS Centre of Excellence for Chronic Diseases, Universidad Peruana Cayetano Heredia, Lima, Peru; Departamento de Medicina, Escuela de Medicina, Universidad Peruana Cayetano Heredia, Lima, Peru; Program in Global Disease Epidemiology and Control, Department of International Health, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD
| | - Victor G Dávila-Román
- Cardiovascular Imaging and Clinical Research Core Laboratory, Cardiovascular Division, School of Medicine, Washington University in St. Louis, St. Louis, MO
| | - Fabiola León-Velarde
- Departamento de Ciencias Biológicas y Fisiológicas, Laboratorio de Adaptación a la Altura, Laboratorios de Investigación y Desarrollo, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Maria Rivera-Ch
- Departamento de Ciencias Biológicas y Fisiológicas, Laboratorio de Adaptación a la Altura, Laboratorios de Investigación y Desarrollo, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Luis Huicho
- Departamento de Ciencias Biológicas y Fisiológicas, Laboratorio de Adaptación a la Altura, Laboratorios de Investigación y Desarrollo, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Antonio Bernabé-Ortiz
- CRONICAS Centre of Excellence for Chronic Diseases, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Robert A Wise
- From the Division of Pulmonary and Critical Care, School of Medicine, Johns Hopkins University, Baltimore, MD
| | - William Checkley
- From the Division of Pulmonary and Critical Care, School of Medicine, Johns Hopkins University, Baltimore, MD; CRONICAS Centre of Excellence for Chronic Diseases, Universidad Peruana Cayetano Heredia, Lima, Peru; Departamento de Medicina, Escuela de Medicina, Universidad Peruana Cayetano Heredia, Lima, Peru.
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21
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Villafuerte FC, Macarlupú JL, Anza-Ramírez C, Corrales-Melgar D, Vizcardo-Galindo G, Corante N, León-Velarde F. Decreased plasma soluble erythropoietin receptor in high-altitude excessive erythrocytosis and Chronic Mountain Sickness. J Appl Physiol (1985) 2014; 117:1356-62. [PMID: 25324511 PMCID: PMC4254844 DOI: 10.1152/japplphysiol.00619.2014] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Accepted: 10/13/2014] [Indexed: 11/22/2022] Open
Abstract
Excessive erythrocytosis (EE) is the hallmark of chronic mountain sickness (CMS), a prevalent syndrome in high-altitude Andean populations. Although hypoxemia represents its underlying stimulus, why some individuals develop EE despite having altitude-normal blood erythropoietin (Epo) concentration is still unclear. A soluble form of the Epo receptor (sEpoR) has been identified in human blood and competes directly for Epo with its membrane counterpart (mEpoR). Thus, reduced levels of circulating sEpoR could lead to higher Epo availability and ultimately to EE. We characterized the relationship between Epo and sEpoR, with hematocrit and hemoglobin concentration in healthy highlanders and CMS patients at 4,340 m in Cerro de Pasco, Peru. Our results show that EE patients show decreased plasma sEpoR levels and can be subdivided into two subgroups of normal and high plasma Epo concentration for the altitude of residence, with hemoglobin concentration rising exponentially with an increasing Epo-to-sEpoR ratio (Epo/sEpoR). Also, we showed that the latter varies as an inverse exponential function of arterial pulse O2 saturation. Our findings suggests that EE is strongly associated with higher Epo/sEpoR values, leading to elevated plasma Epo availability to bind mEpoR, and thereby a stronger stimulus for augmented erythropoiesis. Differences in the altitude normal and high Epo CMS patients with a progressively higher Epo/sEpoR supports the hypothesis of the existence of two genetically different subgroups suffering from EE and possibly different degrees of adaptation to chronic high-altitude hypoxia.
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Affiliation(s)
- Francisco C Villafuerte
- Laboratorio de Fisiología Comparada, Departamento de Ciencias Biológicas y Fisiológicas, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - José Luis Macarlupú
- Laboratorio de Fisiología Comparada, Departamento de Ciencias Biológicas y Fisiológicas, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Cecilia Anza-Ramírez
- Laboratorio de Fisiología Comparada, Departamento de Ciencias Biológicas y Fisiológicas, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Daniela Corrales-Melgar
- Laboratorio de Fisiología Comparada, Departamento de Ciencias Biológicas y Fisiológicas, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Gustavo Vizcardo-Galindo
- Laboratorio de Fisiología Comparada, Departamento de Ciencias Biológicas y Fisiológicas, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Noemí Corante
- Laboratorio de Fisiología Comparada, Departamento de Ciencias Biológicas y Fisiológicas, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Fabiola León-Velarde
- Laboratorio de Fisiología Comparada, Departamento de Ciencias Biológicas y Fisiológicas, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
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22
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Negi PC, Asotra S, V RK, Marwah R, Kandoria A, Ganju NK, Sharma R, Bhardwaj R. Epidemiological study of chronic mountain sickness in natives of Spiti Valley in the Greater Himalayas. High Alt Med Biol 2014; 14:220-9. [PMID: 24067183 DOI: 10.1089/ham.2012.1127] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
AIMS This study determined the prevalence of chronic mountain sickness (CMS) and its predisposing factors among natives of Spiti Valley in the northern state of Indian Himalayas. A cross-sectional survey study was conducted in natives of Spiti Valley aged ≥ 20 years residing at altitudes of 3000 to 4200 meters. CMS was diagnosed using Qinghai criteria. Demographics, behavioral characteristics, specified symptoms of CMS were recorded, including BP, anthropometrics, evidence of RHF, PAH, and severe cyanosis. ECG, echocardiography, PFT, and Sao2 were recorded, and Hb level was estimated with the cyanmethhemoglobin method. RESULTS 694 subjects free of cardiorespiratory diseases were analyzed. Prevalence of CMS was 28.7%, (95% C.I. of 25.9%-32.8%) and was higher in women than in men (36.6% vs. 15.7%, p<0.001). Erythrocythemia and hypoxemia were recorded in 10.5% and 7.5%, respectively. Age, truncal obesity, female gender, altitude of residence, and physical activity index were independent predictors of CMS with z statistics of 4.2, 2.29, -3.7, 2.8, and -2.8, respectively, and were statistically significant p<0.001. 6.2% of the surveyed population had HAPH. CONCLUSION 28.7% (95% C.I. of 25.9%-32.8%) of the natives of the Spiti Valley in the Indian Himalayas are affected with CMS. Higher prevalence of CMS amongst women needs further studies. Westernized lifestyle appears to have predisposition to CMS.
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Affiliation(s)
- Prakash Chand Negi
- Department of Cardiology, Indira Gandhi Medical College , Shimla Himachal Pradesh, India
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23
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Palmer BF, Clegg DJ. Ascent to altitude as a weight loss method: the good and bad of hypoxia inducible factor activation. Obesity (Silver Spring) 2014; 22:311-7. [PMID: 23625659 PMCID: PMC4091035 DOI: 10.1002/oby.20499] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2013] [Accepted: 04/18/2013] [Indexed: 12/17/2022]
Abstract
OBJECTIVE Given the epidemic of obesity worldwide there is a need for more novel and effective weight loss methods. Altitude is well known to be associated with weight loss and has actually been used as a method of weight reduction in obese subjects. This review demonstrates the critical role of hypoxia inducible factor (HIF) in bringing about reductions in appetite and increases in energy expenditure characteristic of hypobaric hypoxia DESIGN AND METHODS A MEDLINE search of English language articles through February 2013 identified publications associating altitude or hypobaric hypoxia with key words to include HIF, weight loss, appetite, basal metabolic rate, leptin, cellular energetics, and obesity. The data from these articles were synthesized to formulate a unique and novel mechanism by which HIF activation leads to alterations in appetite, basal metabolic rate, and reductions in body adiposity. RESULTS A synthesis of previously published literature revealed mechanisms by which altitude induces activation of HIF, thereby suggesting this transcription factor regulates changes in cellular metabolism/energetics, activation of the central nervous system, as well as peripheral pathways leading to reductions in food intake and increases in energy expenditure. CONCLUSIONS Here a unifying hypothesis is present suggesting that activation of HIF under conditions of altitude potentially leads to metabolic benefits that are dose dependent, gender and genetic specific, and results in adverse effects if the exposure is extreme.
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Affiliation(s)
- Biff F Palmer
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA
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24
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Gonzales GF. Serum testosterone levels and excessive erythrocytosis during the process of adaptation to high altitudes. Asian J Androl 2013; 15:368-74. [PMID: 23524530 DOI: 10.1038/aja.2012.170] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Populations living at high altitudes (HAs), particularly in the Peruvian Andes, are characterized by a mixture of subjects with erythrocytosis (16 g dl(-1)<haemoglobin (Hb)≤21 g dl(-1)) and others with excessive erythrocytosis (EE) (Hb>21 g dl(-1)). Elevated haemoglobin values (EE) are associated with chronic mountain sickness, a condition reflecting the lack of adaptation to HA. According to current data, native men from regions of HA are not adequately adapted to live at such altitudes if they have elevated serum testosterone levels. This seems to be due to an increased conversion of dehydroepiandrosterone sulphate (DHEAS) to testosterone. Men with erythrocytosis at HAs show higher serum androstenedione levels and a lower testosterone/androstenedione ratio than men with EE, suggesting reduced 17beta-hydroxysteroid dehydrogenase (17beta-HSD) activity. Lower 17beta-HSD activity via Δ4-steroid production in men with erythrocytosis at HA may protect against elevated serum testosterone levels, thus preventing EE. The higher conversion of DHEAS to testosterone in subjects with EE indicates increased 17beta-HSD activity via the Δ5-pathway. Currently, there are various situations in which people live (human biodiversity) with low or high haemoglobin levels at HA. Antiquity could be an important adaptation component for life at HA, and testosterone seems to participate in this process.
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Affiliation(s)
- Gustavo F Gonzales
- High Altitude Research Institute and Department of Biological and Physiological Sciences, Faculty of Sciences and Philosophy, Universidad Peruana Cayetano Heredia, Lima 31, Peru.
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25
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Julian CG, Vargas E, Gonzales M, Dávila RD, Ladenburger A, Reardon L, Schoo C, Powers RW, Lee-Chiong T, Moore LG. Sleep-disordered breathing and oxidative stress in preclinical chronic mountain sickness (excessive erythrocytosis). Respir Physiol Neurobiol 2013; 186:188-96. [PMID: 23380170 DOI: 10.1016/j.resp.2013.01.016] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2012] [Revised: 01/21/2013] [Accepted: 01/22/2013] [Indexed: 11/26/2022]
Abstract
Chronic mountain sickness (CMS) is considered to be a loss of ventilatory acclimatization to high altitude (>2500m) resulting in marked arterial hypoxemia and polycythemia. This case-control study explores the possibility that sleep-disordered breathing (SDB) and associated oxidative stress contribute to the etiology of CMS. Nocturnal respiratory and [Formula: see text] patterns were measured using standard polysomnography techniques and compared between male high-altitude residents (aged 18-25) with preclinical CMS (excessive erythrocytosis (EE), n=20) and controls (n=19). Measures of oxidative stress and antioxidant status included isoprostanes (8-iso-PGF2alpha), superoxide dismutase and ascorbic acid. EE cases had a greater apnea-hypopnea index, a higher frequency of apneas (central and obstructive) and hypopneas during REM sleep, and lower nocturnal [Formula: see text] compared to controls. 8-iso-PGF2alpha was greater in EE than controls, negatively associated with nocturnal [Formula: see text] , and positively associated with hemoglobin concentration. Mild sleep-disordered breathing and oxidative stress are evident in preclinical CMS, suggesting that the resolution of nocturnal hypoxemia or antioxidant treatment may prevent disease progression.
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Affiliation(s)
- Colleen Glyde Julian
- Altitude Research Center, Department of Emergency Medicine, University of Colorado Denver, Anschutz Medical Campus, Aurora, CO, USA.
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Lahm T, Albrecht M, Fisher AJ, Selej M, Patel NG, Brown JA, Justice MJ, Brown MB, Van Demark M, Trulock KM, Dieudonne D, Reddy JG, Presson RG, Petrache I. 17β-Estradiol attenuates hypoxic pulmonary hypertension via estrogen receptor-mediated effects. Am J Respir Crit Care Med 2012; 185:965-80. [PMID: 22383500 DOI: 10.1164/rccm.201107-1293oc] [Citation(s) in RCA: 128] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
RATIONALE 17β-Estradiol (E2) attenuates hypoxic pulmonary vasoconstriction and hypoxic pulmonary hypertension (HPH) through an unknown mechanism that may involve estrogen receptors (ER) or E2 conversion to catecholestradiols and methoxyestradiols with previously unrecognized effects on cardiopulmonary vascular remodeling. OBJECTIVES To determine the mechanism by which E2 exerts protective effects in HPH. METHODS Male rats were exposed to hypobaric hypoxia while treated with E2 (75 μg/kg/d) or vehicle. Subgroups were cotreated with pharmacologic ER-antagonist or with inhibitors of E2-metabolite conversion. Complementary studies were performed in rats cotreated with selective ERα- or ERβ-antagonist. Hemodynamic and pulmonary artery (PA) and right ventricular (RV) remodeling parameters, including cell proliferation, cell cycle, and autophagy, were measured in vivo and in cultured primary rat PA endothelial cells. MEASUREMENTS AND MAIN RESULTS E2 significantly attenuated HPH endpoints. Hypoxia increased ERβ but not ERα lung vascular expression. Co-treatment with nonselective ER inhibitor or ERα-specific antagonist rendered hypoxic animals resistant to the beneficial effects of E2 on cardiopulmonary hemodynamics, whereas ERα- and ERβ-specific antagonists opposed the remodeling effects of E2. In contrast, inhibition of E2-metabolite conversion did not abolish E2 protection. E2-treated hypoxic animals exhibited reduced ERK1/2 activation and increased expression of cell-cycle inhibitor p27(Kip1) in lungs and RV, with up-regulation of lung autophagy. E2-induced signaling was recapitulated in hypoxic but not normoxic endothelial cells, and was associated with decreased vascular endothelial growth factor secretion and cell proliferation. CONCLUSIONS E2 attenuates hemodynamic and remodeling parameters in HPH in an ER-dependent manner, through direct antiproliferative mechanisms on vascular cells, which may provide novel nonhormonal therapeutic targets for HPH.
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Affiliation(s)
- Tim Lahm
- Division of Pulmonary, Allergy, Critical Care and Occupational Medicine, Department of Medicine, Indiana University School of Medicine, Indianapolis, Indiana, USA.
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Li X, Pei T, Xu H, Tao F, You H, Liu Y, Gao Y. Ecological study of community-level factors associated with chronic mountain sickness in the young male chinese immigrant population in Tibet. J Epidemiol 2012; 22:136-43. [PMID: 22343324 PMCID: PMC3798592 DOI: 10.2188/jea.je20110058] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Background Chronic mountain sickness (CMS) is a complex medical and public health problem that seriously affects highland immigrants. This study investigated relationships between community-level factors and CMS. Methods In this ecological study, data on age- and ethnicity-standardized CMS rates, community factors, and controlling variables were obtained from 2009–2010 surveys of 108 Chinese highland military units. Associations among variables were examined using correlation tests, analyses of covariance, and logistic regression. Results The rate of CMS ranged from 1.25% to 36.58% (mean: 14.65%, standard deviation: 8.15%) among military units. Partial correlation tests indicated that medicine expenditure was strongly negatively correlated with CMS (r = −0.267, P = 0.005). Analyses of covariance indicated that communities with oxygen-generating systems had lower CMS rates (F = 9.780, P = 0.002), whereas urban location (F = 5.442, P = 0.022) and construction duty (F = 4.735, P = 0.011) were associated with higher CMS rates. The multiple logistic model showed that medicine expenditure (OR = 0.897, P = 0.022), oxygen-generating system (available vs unavailable: OR = 0.827, P = 0.020), community type (urban vs rural: OR = 1.228, P = 0.019), and occupation (construction vs logistics: OR = 1.240, P = 0.029) were significantly associated with CMS. Conclusions We identified community-level, health-related factors that were associated with CMS among young male immigrants. To alleviate the burden of CMS in these highland immigrant populations, further investment should be made in medicine and oxygen-generating systems, and preventive interventions should be implemented among construction workers. Further research should investigate the effects of urbanization on CMS development.
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Affiliation(s)
- Xiaoxiao Li
- Department of Health Service, College of High Altitude Military Medicine, Third Military Medical University, Chongqing, P. R. China
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Lumbroso D, Lemoine A, Gonzales M, Villalpando G, Seaborn T, Joseph V. Life-long consequences of postnatal normoxia exposure in rats raised at high altitude. J Appl Physiol (1985) 2011; 112:33-41. [PMID: 21998271 DOI: 10.1152/japplphysiol.01043.2011] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We tested the hypothesis that exposure of high-altitude (HA) rats to a period of postnatal normoxia has long-term consequences on the ventilatory and hematological acclimatization in adults. Male and female HA rats (3,600 m, Po(2) ≃ 100 Torr; La Paz, Bolivia) were exposed to normal room air [HA control (HACont)] or enriched oxygen (32% O(2); Po(2) ≃ 160 Torr) from 1 day before to 15 days after birth [HA postnatal normoxia (HApNorm)]. Hematocrit and hemoglobin values were assessed at 2, 12, and 32 wk of age. Cardiac and lung morphology were assessed at 12 wk by measuring right ventricular hypertrophy (pulmonary hypertension index) and lung air space-to-tissue ratio (indicative of alveolarization). Respiratory parameters under baseline conditions and in response to 32% O(2) for 10 min (relieving the ambient hypoxic stimulus) were measured by whole body plethysmography at 12 wk. Finally, we performed a survival analysis up to 600 days of age. Compared with HACont, HApNorm rats had reduced hematocrit and hemoglobin levels at all ages (both sexes); reduced right ventricular hypertrophy (both sexes); lower air space-to-tissue ratio in the lungs (males only); reduced CO(2) production rate, but higher oxygen uptake (males only); and similar respiratory frequency, tidal volume, and minute ventilation. When breathing 32% O(2), HApNorm male rats had a stronger decrease of minute ventilation than HACont. HApNorm rats had a marked tendency toward longer survival throughout the study. We conclude that exposure to ambient hypoxia during postnatal development in HA rats has deleterious consequences on acclimatization to hypoxia as adults.
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Affiliation(s)
- Delphine Lumbroso
- Department of Pediatrics, Laval University, Centre de Recherche Centre Hospitalier Universitaire de Québec, Hôpital St-François d'Assise, Quebec, Canada
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Abstract
Large numbers of people travel to high altitudes, entering an environment of hypobaric hypoxia. Exposure to low oxygen tension leads to a series of important physiologic responses that allow individuals to tolerate these hypoxic conditions. However, in some cases hypoxia triggers maladaptive responses that lead to various forms of acute and chronic high altitude illness, such as high-altitude pulmonary edema or chronic mountain sickness. Because the respiratory system plays a critical role in these adaptive and maladaptive responses, patients with underlying lung disease may be at increased risk for complications in this environment and warrant careful evaluation before any planned sojourn to higher altitudes. In this review, we describe respiratory disorders that occur with both acute and chronic exposures to high altitudes. These disorders may occur in any individual who ascends to high altitude, regardless of his/her baseline pulmonary status. We then consider the safety of high-altitude travel in patients with various forms of underlying lung disease. The available data regarding how these patients fare in hypoxic conditions are reviewed, and recommendations are provided for management prior to and during the planned sojourn.
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Affiliation(s)
- Joshua O Stream
- University of Utah, Department of Anesthesiology, 30 North 1900 East, Room 3C444, Salt Lake City, UT 84132, USA.
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Gassmann M, Pfistner C, Doan VD, Vogel J, Soliz J. Impaired ventilatory acclimatization to hypoxia in female mice overexpressing erythropoietin: unexpected deleterious effect of estradiol in carotid bodies. Am J Physiol Regul Integr Comp Physiol 2010; 299:R1511-20. [DOI: 10.1152/ajpregu.00205.2010] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Apart from enhancing the production of red blood cells, erythropoietin (Epo) alters the ventilatory response when oxygen supply is reduced. We recently demonstrated that Epo's beneficial effect on the ventilatory response to acute hypoxia is sex dependent, with female mice being better able to cope with reduced oxygenation. In the present work, we hypothesized that ventilatory acclimatization to chronic hypoxia (VAH) in transgenic female mice (Tg6) harboring high levels of Epo in the brain and blood will also be improved compared with wild-type (WT) animals. Surprisingly, VAH was blunted in Tg6 female mice. To define whether this phenomenon had a central (brain stem respiratory centers) and/or peripheral (carotid bodies) origin, a bilateral transection of carotid sinus nerve (chemodenervation) was performed. This procedure allowed the analysis of the central response in the absence of carotid body information. Interestingly, chemodenervation restored the VAH in Tg6 mice, suggesting that carotid bodies were responsible for the blunted response. Coherently with this observation, the sensitivity to oxygen alteration in arterial blood (Dejour test) after chronic hypoxia was lower in transgenic carotid bodies compared with the WT control. As blunted VAH occurred in female but not male transgenic mice, the involvement of sex female steroids was obvious. Indeed, measurement of sexual female hormones revealed that the estradiol serum level was 4 times higher in transgenic mice Tg6 than in WT animals. While ovariectomy decreased VAH in WT females, this treatment restored VAH in Tg6 female mice. In line with this observation, injections of estradiol in ovariectomized Tg6 females dramatically reduced the VAH. We concluded that during chronic hypoxia, estradiol in carotid bodies suppresses the Epo-mediated elevation of ventilation. Considering the increased application of recombinant Epo for a variety of disorders, our data imply the need to take the patient's hormonal status into consideration.
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Affiliation(s)
- Max Gassmann
- Institute of Veterinary Physiology, Vetsuisse Faculty, and Zurich Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland; and
| | - Christine Pfistner
- Institute of Veterinary Physiology, Vetsuisse Faculty, and Zurich Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland; and
| | - Van Diep Doan
- Unité de Recherche en Périnatalogie, Centre Hospitalier Universitaire de Québec, Hôpital Saint-François d'Assise, Département de Pédiatrie, Université Laval, Québec, Canada
| | - Johannes Vogel
- Institute of Veterinary Physiology, Vetsuisse Faculty, and Zurich Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland; and
| | - Jorge Soliz
- Institute of Veterinary Physiology, Vetsuisse Faculty, and Zurich Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland; and
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Abstract
Acclimatization to long-term hypoxia takes place at high altitude and allows gradual improvement of the ability to tolerate the hypoxic environment. An important component of this process is the hypoxic ventilatory acclimatization (HVA) that develops over several days. HVA reveals profound cellular and neurochemical re-organization occurring both in the peripheral chemoreceptors and in the central nervous system (in brainstem respiratory groups). These changes lead to an enhanced activity of peripheral chemoreceptor and re-inforce the central translation of peripheral inputs to efficient respiratory motor activity under the steady low O(2) pressure. We will review the cellular processes underlying these changes with a particular emphasis on changes of neurotransmitter function and ion channel properties in peripheral chemoreceptors, and present evidence that low O(2) level acts directly on brainstem nuclei to induce cellular changes contributing to maintain a high tonic respiratory drive under chronic hypoxia.
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Affiliation(s)
- Vincent Joseph
- Department of Pediatrics, Laval University, Centre de Recherche (D0-711), Hôpital St-François d'Assise, 10 rue de l'Espinay, Quebec, QC, G1L 3L5, Canada.
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Lumbroso D, Joseph V. Impaired acclimatization to chronic hypoxia in adult male and female rats following neonatal hypoxia. Am J Physiol Regul Integr Comp Physiol 2009; 297:R421-7. [PMID: 19494172 DOI: 10.1152/ajpregu.00068.2009] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
We tested the hypothesis that neonatal exposure to hypoxia alters acclimatization to chronic hypoxia later in life. Rat pups were exposed to normobaric hypoxia (12% O(2); nHx group) in a sealed chamber, or to normoxia (21% O(2); nNx group) from the day before birth to postnatal day 10. The animals were then raised in normal conditions until reaching 12 wk of age. At this age, we assessed ventilatory and hematological acclimatization to chronic hypoxia by exposing male and female nHx and nNx rats for 2 wk to 10% O(2). Minute ventilation, metabolic rate, hypoxic ventilatory response, hematocrit, and hemoglobin levels were measured both before and after acclimatization. We also quantified right ventricular hypertrophy as an index of pulmonary hypertension both before and after acclimatization. There was a significant effect of neonatal hypoxia that decreases ventilatory response (relative to metabolic rate, VE/VCO(2)) to acute hypoxia before acclimatization in males but not in females. nHx rats had an impaired acclimatization to chronic hypoxia characterized by altered respiratory pattern and elevated hematocrit and hemoglobin levels after acclimatization, in both males and females. Right ventricular hypertrophy was present before and after acclimatization in nHx rats, indicating that neonatal hypoxia results in pulmonary hypertension in adults. We conclude that neonatal hypoxia impairs acclimatization to chronic hypoxia in adults and may be a factor contributing to the establishment of chronic mountain sickness in humans living at high altitude.
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Affiliation(s)
- Delphine Lumbroso
- Department of Pediatrics, Laval University, Centre de Recherche, Hôpital St-François d'Assise, Quebec, Canada
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Gonzales GF, Gasco M, Tapia V, Gonzales-Castañeda C. High serum testosterone levels are associated with excessive erythrocytosis of chronic mountain sickness in men. Am J Physiol Endocrinol Metab 2009; 296:E1319-25. [PMID: 19318512 PMCID: PMC2692401 DOI: 10.1152/ajpendo.90940.2008] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Chronic mountain sickness (CMS) is characterized by excessive erythrocytosis (EE) secondary to hypoventilation. Erythropoietin (Epo) and testosterone regulate erythrocyte production. Low thyroid hormone levels are also associated to hypoventilation. Hence, these hormones can play a role in etiopathogeny of EE. The purpose of this study was to elucidate the effect of sexual and thyroid hormones and Epo in residents from Lima (150 m) and Cerro de Pasco (4,340 m), Peru, and the response to human chorionic gonadotrophin stimulation (hCG). Three groups, one at low altitude and two at high altitude [1 with hemoglobin values >16-21 g/dl and the second with Hb >or=21 g/dl (EE)], were studied. hCG was administered intramuscularly in a single dose (1,000 IU), and blood samples were obtained at 0, 6, 12, 24, 48, and 72 h after injection. High-altitude natives present similar levels of gonadotropins and thyroid hormones but lower dehydroepiandrosterone sulphate (DHEAS) levels (P < 0.01) and greater Epo (P < 0.01), 17alpha-hydroxyprogesterone (P < 0.01), and testosterone levels (P < 0.01) than those at 150 m. Serum testosterone levels (524.13 +/- 55.91 microg/dl vs. 328.14 +/- 53.23 ng/dl, means +/- SE; P < 0.05) and testosterone/DHEAS ratios are higher (7.98 +/- 1.1 vs. 3.65 +/- 1.1; P < 0.01) and DHEAS levels lower in the EE group (83.85 +/- 14.60 microg/dl vs. 148.95 +/- 19.11 ug/dl; P < 0.05), whereas Epo was not further affected. Testosterone levels were highest and DHEAS levels lowest in the EE group at all times after hCG stimulation. In conclusion, high androgen activity could be involved in the etiopathogeny of CMS. This evidence provides an opportunity to develop new therapeutic strategies.
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Affiliation(s)
- Gustavo F Gonzales
- Laboratory of Endocrinology and Reproduction, Faculty of Sciences and Philosophy, "Alberto Cazorla Tálleri" Universidad Peruana Cayetano Heredia, Ave. Honorio Delgado 430, Lima 31, Peru.
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Soliz J, Thomsen JJ, Soulage C, Lundby C, Gassmann M. Sex-dependent regulation of hypoxic ventilation in mice and humans is mediated by erythropoietin. Am J Physiol Regul Integr Comp Physiol 2009; 296:R1837-46. [PMID: 19321698 DOI: 10.1152/ajpregu.90967.2008] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Acclimatization to hypoxic exposure relies on an elevated ventilation and erythropoietic activity. We recently proposed that erythropoietin (Epo) links both responses: apart from red blood cell production, cerebral and plasma Epo interact with the central and peripheral respiratory centers. Knowing that women cope better than men with reduced oxygen supply (as observed at high altitude), we analyzed the hypoxic ventilatory response in Epo-overexpressing transgenic male and female mice with high Epo levels in brain and plasma (Tg6) or in wild-type animals injected with recombinant human Epo (rhEpo). Exposure to moderate and severe hypoxia as well as to hyperoxia and injection of domperidone, a potent peripheral ventilatory stimulant, revealed that the presence of transgenic or rhEpo extensively increased the hypoxic ventilatory response in female mice compared with their corresponding male siblings. Alterations of catecholamines in the brain stem's respiratory centers were also sex dependent. In a proof-of-concept study, human volunteers were intravenously injected with 5,000 units rhEpo and subsequently exposed to 10% oxygen. Compared with men, the hypoxic ventilatory response was significantly increased in women. We conclude that Epo exerts a sex-dependent impact on hypoxic ventilation improving the response in female mice and in women that most probably involves sexual hormones. Our data provides an explanation as to why women are less susceptible to hypoxia-associated syndromes than men.
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Affiliation(s)
- Jorge Soliz
- nstitute of Veterinary Physiology, Vetsuisse Faculty, and Zurich Center for Integrative Human Physiology, University of Zurich, Zurich CH-8057, Switzerland
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Soliz J, Soulage C, Borter E, van Patot MT, Gassmann M. Ventilatory responses to acute and chronic hypoxia are altered in female but not male Paskin-deficient mice. Am J Physiol Regul Integr Comp Physiol 2008; 295:R649-58. [DOI: 10.1152/ajpregu.00876.2007] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Proteins harboring a Per-Arnt-Sim (PAS) domain are versatile and allow archaea, bacteria, and plants to sense oxygen partial pressure, as well as light intensity and redox potential. A PAS domain associated with a histidine kinase domain is found in FixL, the oxygen sensor molecule of Rhizobium species. PASKIN is the mammalian homolog of FixL, but its function is far from being understood. Using whole body plethysmography, we evaluated the ventilatory response to acute and chronic hypoxia of homozygous deficient male and female PASKIN mice ( Paskin −/−). Although only slight ventilatory differences were found in males, female Paskin −/− mice increased ventilatory response to acute hypoxia. Unexpectedly, females had an impaired ability to reach ventilatory acclimatization in response to chronic hypoxia. Central control of ventilation occurs in the brain stem respiratory centers and is modulated by catecholamines via tyrosine hydroxylase (TH) activity. We observed that TH activity was altered in male and female Paskin −/− mice. Peripheral chemoreceptor effects on ventilation were evaluated by exposing animals to hyperoxia (Dejours test) and domperidone, a peripheral ventilatory stimulant drug directly affecting the carotid sinus nerve discharge. Male and female Paskin −/− had normal peripheral chemosensory (carotid bodies) responses. In summary, our observations suggest that PASKIN is involved in the central control of hypoxic ventilation, modulating ventilation in a gender-dependent manner.
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Appenzeller O, Minko T, Qualls C, Pozharov V, Gamboa J, Gamboa A, Wang Y. Gene expression, autonomic function and chronic hypoxia:lessons from the Andes. Clin Auton Res 2006; 16:217-22. [PMID: 16583294 DOI: 10.1007/s10286-006-0338-3] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2005] [Accepted: 08/12/2005] [Indexed: 10/24/2022]
Abstract
Autonomic function is altered by altitude in sojourners and natives. We hypothesized that these physiologic responses are modulated by changes in gene expression. We compared gene product levels in 20 natives of Cerro de Pasco (CP), (4338 m), 10 of which had chronic mountain sickness (CMS) established by a CMS-scoring system, with gene products in the same men after 1 h at sea level. We further compared the results with those obtained from 10 US men residing at 1500 m. We measured gene products in white cells by reverse transcription polymerase chain reaction (RT-PCR). We focused on genes important in vascular autonomic physiology, and/or activated by hypoxia; hypoxia inducible factor 1-alpha (HIF 1-alpha), 2 splicing variants of vascular endothelial growth factor (VEGF); VEGF-121, VEGF-165, and phosphoglycerate kinase 1 (PGK 1). Normal CP natives showed high expression of all genes in CP, compared to US controls. Within 1 h of arrival at sea level, they had comparable levels to US residents. In CMS, the gene products were higher in CP. Although gene products decreased in Lima in this group, they never reached US values. VEGF 121 and 165 were correlated (P<0.001). VEGF 165 was higher in CMS in CP (P=0.006), and was positively correlated with CMS-score (R=0.86, P<0.001), and negatively correlated with arterial saturation (R=-0.79, P<0.001). Our findings underscore the changes in gene expression levels in intact humans in response to environmental stress. These changes may support the physiologic alterations induced by the ambient hypoxia at altitude and impact organism survival. They also suggest therapeutic strategies for autonomic and neurodegenerative diseases at sea level.
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Affiliation(s)
- Otto Appenzeller
- New Mexico Health Enhancement and Marathon Clinics Research Foundation, Albuquerque, NM 87122-1424, USA.
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Richalet JP, Rivera M, Bouchet P, Chirinos E, Onnen I, Petitjean O, Bienvenu A, Lasne F, Moutereau S, León-Velarde F. Acetazolamide: a treatment for chronic mountain sickness. Am J Respir Crit Care Med 2005; 172:1427-33. [PMID: 16126936 DOI: 10.1164/rccm.200505-807oc] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
RATIONALE Chronic mountain sickness or Monge's disease is characterized by an excessive polycythemia in high-altitude dwellers, with a prevalence of 5 to 18% above 3,200 m. To date, no pharmacologic treatment is available. OBJECTIVES We evaluated the efficacy of acetazolamide in the treatment of chronic mountain sickness and the importance of nocturnal hypoxemia in its pathophysiology. METHODS A double-blind placebo-controlled study was performed in three groups of patients from Cerro de Pasco, Peru (4,300 m), treated orally for 3 weeks with placebo (n = 10), 250 mg of acetazolamide (n = 10), or 500 mg of acetazolamide (n = 10), daily. RESULTS Acetazolamide decreased hematocrit by 7.1% (p < 0.001) and 6.7% (p < 0.001), serum erythropoietin by 67% (p < 0.01) and 50% (p < 0.001), and serum soluble transferrin receptors by 11.1% (p < 0.05) and 3.4% (p < 0.001), and increased serum ferritin by 540% (p < 0.001) and 134% (p < 0.001), for groups treated with 250 and 500 mg of acetazolamide, respectively. Acetazolamide (250 mg) increased nocturnal arterial O(2) saturation by 5% (p < 0.01) and decreased mean nocturnal heart rate by 11% (p < 0.05) and the number of apnea-hypopnea episodes during sleep by 74% (p < 0.05). The decrease in erythropoietin was attributed mainly to the acetazolamide-induced increase in ventilation and arterial O(2) saturation. CONCLUSIONS Acetazolamide, the first efficient pharmacologic treatment of chronic mountain sickness without adverse effects, reduces hypoventilation, which may be accentuated during sleep, and blunts erythropoiesis. Its low cost may allow wide development with a considerable positive impact on public health in high-altitude regions.
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Affiliation(s)
- Jean-Paul Richalet
- Laboratoire EA 2363, UFR SMBH, 74 rue Marcel Cachin, 93017 Bobigny Cedex, France.
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Rhodes J. Comparative physiology of hypoxic pulmonary hypertension: historical clues from brisket disease. J Appl Physiol (1985) 2005; 98:1092-100. [PMID: 15703167 DOI: 10.1152/japplphysiol.01017.2004] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Some of the most valuable contributions to science have come about serendipitously, and, in 1913, when George Glover and Issac Newsom were commissioned by Colorado cattle ranchers to study high mountain disease, there was no way to anticipate the tremendous impact they would have on the study of high-altitude cardiopulmonary physiology. It was through the study of this agricultural malady that the correlation between chronic hypoxia, pulmonary hypertension, medial hypertrophy of the small pulmonary arteries, and right ventricular (RV) hypertrophy was recognized. The amount of vascular smooth muscle comprising the medial layer of pulmonary arteries varies significantly across species and can be used to predict the magnitude of pulmonary hypertension and RV hypertrophy elicited in response to chronic hypoxia. Within species, age and gender both significantly influence the severity of chronic hypoxic pulmonary hypertension and RV hypertrophy. However, despite all that we now know about hypoxic pulmonary hypertension, the specific mechanism(s) that differentiate the hypo- from the hyperresponder have yet to be elucidated. Adventitial fibroblast differentiation, circulating vascular progenitor cells, the presence or absence of specific vascular smooth muscle phenotypes, the upregulation or downregulation of vasoactive mediators, splice variants of oxygen-sensitive transcription factors, upregulation of growth factors, Ca(2+) sensitization, and/or the Rho/Rho-kinases signaling cascade could all potentially play a role in determining the extent of the vascular response to hypoxia within a species. Understanding the mechanisms that determine why some people, as well as some animals, exhibit a marked susceptibility to hypoxia is an important endeavor with far-reaching implications.
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Affiliation(s)
- Jann Rhodes
- Department of Biological Science, College of Veterinary Medicine and Biomedical Science, Colorado State University, Fort Collins, CO 80523-1683, USA.
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Wu T, Wang X, Wei C, Cheng H, Wang X, Li Y, Zhao H, Young P, Li G, Wang Z. Hemoglobin levels in Qinghai-Tibet: different effects of gender for Tibetans vs. Han. J Appl Physiol (1985) 2005; 98:598-604. [PMID: 15258131 DOI: 10.1152/japplphysiol.01034.2002] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The Tibetan population, long a resident on the Qinghai-Tibetan Plateau, has lower hemoglobin concentrations than Han Chinese migrants, but it is incompletely known how gender affects the hemoglobin concentrations in the two populations at various altitudes. Measurements of hemoglobin concentration were obtained in 5,887 healthy male and female Tibetan and Han residents aged 5–60 yr, at altitudes of 2,664, 3,813, 4,525, and 5,200 m. Multiple regression equations showed the β-coefficients for altitude and for age were higher ( P < 0.05) in Han men than in Tibetan men and in Han women than in Tibetan women. Analysis indicated a significant three-way interaction between altitude, gender, and ethnicity (χ2 = 3.72, P = 0.05). With increasing altitude, men progressively had more hemoglobin than women in the Han, but not the Tibetan, population. Above 2,664 m, this gender-related difference in hemoglobin concentration increased from childhood to young adulthood more in Han than in Tibetans. We suggest that the Han-Tibetan ethnic difference in the effect of altitude on hemoglobin concentration depends to a large extent on gender.
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Affiliation(s)
- Tianyi Wu
- High Altitude Medical Research Institute, Nanchua West Road #344, Xining, Qinghai, 810012, PR China.
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Doan VD, Gagnon S, Joseph V. Prenatal blockade of estradiol synthesis impairs respiratory and metabolic responses to hypoxia in newborn and adult rats. Am J Physiol Regul Integr Comp Physiol 2004; 287:R612-8. [PMID: 15142837 DOI: 10.1152/ajpregu.00627.2003] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We tested the hypothesis that estradiol modifies respiratory control in pregnant rats and participates in the development of respiratory chemoreflexes in fetuses. Pregnant rats (n = 12) received daily subcutaneous injections of vehicle (Veh, n = 6) or 4-androsten-4-ol-3,17-dione acetate (ATD; inhibitor of estradiol synthesis; n = 6; 5 mg/day in vehicle) from gestational day 16 (G16) to delivery. Baseline ventilation (whole body plethysmography) and metabolic rate [oxygen consumption (Vo(2))] were determined at G14 and G20, in pups [on postnatal day 3 (P3) and P20] and in adult rats (on P70) born to Veh- or ATD-treated mothers. Hypoxic chemoreflex was assessed in P3 rats by acute exposure to 60% O(2) and in P20 or P70 rats by moderate hypoxia (12% O(2), 30 min). ATD treatment reduced circulating estradiol in pregnant dams at G20 without producing changes in the circulating level of estradiol precursors (testosterone and androstenedione). ATD-treated dams showed impaired respiratory adjustment to late gestation. Pups born to ATD mothers had higher resting Vo(2) (+23% at P3, +21% at P20), respiratory frequency (+15% at P3, +12% at P20), and minute ventilation (+11% at P3, +18% at P20) than pups from Veh mothers. Respiratory decrease during acute hyperoxic exposure at P3 was -9.7% in Veh (P < 0.05 vs. room air) and only -2.6% (P = not significant) in ATD pups. In P20 ATD rats, hypoxic ventilatory response was attenuated compared with Veh. In P20 and P70 rats, the drop of Vo(2) in hypoxia (-31% in P70, P < 0.0001) was not observed in ATD rats. We conclude that estradiol secreted during late gestation is necessary for respiratory adjustment to pregnancy and is required for adequate development of respiratory and metabolic control in the offspring.
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Affiliation(s)
- V D Doan
- Department of Pediatrics, Laval University, Centre de Recherche CHUQ, Hôpital St. François d'Assise, Local D0-711, 10 Rue de l'Espinay, G1L 3L5 Quebec, Quebec, Canada
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Joseph V, Soliz J, Soria R, Pequignot J, Favier R, Spielvogel H, Pequignot JM. Dopaminergic metabolism in carotid bodies and high-altitude acclimatization in female rats. Am J Physiol Regul Integr Comp Physiol 2002; 282:R765-73. [PMID: 11832397 DOI: 10.1152/ajpregu.00398.2001] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We tested the hypothesis that ovarian steroids stimulate breathing through a dopaminergic mechanism in the carotid bodies. In ovariectomized female rats raised at sea level, domperidone, a peripheral D2-receptor antagonist, increased ventilation in normoxia (minute ventilation = +55%) and acute hypoxia (+32%). This effect disappeared after 10 daily injections of ovarian steroids (progesterone + estradiol). At high altitude (3,600 m, Bolivian Institute for High-Altitude Biology-IBBA, La Paz, Bolivia), neutered females had higher carotid body tyrosine hydroxylase activity (the rate-limiting enzyme for catecholamine synthesis: +129%) and dopamine utilization (+150%), lower minute ventilation (-30%) and hypoxic ventilatory response (-57%), and higher hematocrit (+18%) and Hb concentration (+21%) than intact female rats. Consistent signs of arterial pulmonary hypertension (right ventricular hypertrophy) also appeared in ovariectomized females. None of these parameters was affected by gonadectomy in males. Our results show that ovarian steroids stimulate breathing by lowering a peripheral dopaminergic inhibitory drive. This process may partially explain the deacclimatization of postmenopausal women at high altitude.
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Affiliation(s)
- Vincent Joseph
- Centre d'Etude des Rythmes Biologiques, Université Libre de Bruxelles-Hôpital Erasme, B-1070 Brussels, Belgium
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Reeves JT, Zamudio S, Dahms TE, Asmus I, Braun B, Butterfield GE, McCullough RG, Muza SR, Rock PB, Moore LG. Erythropoiesis in women during 11 days at 4,300 m is not affected by menstrual cycle phase. J Appl Physiol (1985) 2001; 91:2579-86. [PMID: 11717222 DOI: 10.1152/jappl.2001.91.6.2579] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Because the ovarian steroid hormones, progesterone and estrogen, have higher blood levels in the luteal (L) than in the follicular (F) phase of the menstrual cycle, and because of their known effects on ventilation and hematopoiesis, we hypothesized that less hypoxemia and less erythropoiesis would occur in the L than the F phase of the cycle after arrival at altitude. We examined erythropoiesis with menstrual cycle phase in 16 women (age 22.6 +/- 0.6 yr). At sea level, 11 of 16 women were studied during both menstrual cycle phases, and, where comparison within women was available, cycle phase did not alter erythropoietin (n = 5), reticulocyte count (n = 10), and red cell volume (n = 9). When all 16 women were taken for 11 days to 4,300-m altitude (barometric pressure = 462 mmHg), paired comparisons within women showed no differences in ovarian hormone concentrations at sea level vs. altitude on menstrual cycle day 3 or 10 for either the F (n = 11) or the L (n = 5) phase groups. Arterial oxygen saturation did not differ between the F and L groups at altitude. There were no differences by cycle phase on day 11 at 4,300 m for erythropoietin [22.9 +/- 4.7 (L) vs. 18.8 +/- 3.4 mU/ml (F)], percent reticulocytes [1.9 +/- 0.1 (L) vs. 2.1 +/- 0.3% (F)], hemoglobin [13.5 +/- 0.3 (L) vs. 13.7 +/- 0.3 g/100 ml (F)], percent hematocrit [40.6 +/- 1.4 (L) vs. 40.7 +/- 1.0% (F)], red cell volume [31.1 +/- 3.6 (L) vs. 33.0 +/- 1.6 ml/kg (F)], and blood ferritin [8.9 +/- 1.7 (L) vs. 10.2 +/- 0.9 microg/l (F)]. Blood level of erythropoietin was related (r = 0.77) to arterial oxygen saturation but not to the levels of progesterone or estradiol. We conclude that erythropoiesis was not altered by menstrual cycle phase during the first days at 4,300-m altitude.
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Affiliation(s)
- J T Reeves
- University of Colorado Health Sciences Center, Denver, CO 80262, USA.
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León-Velarde F, Gamboa A, Chuquiza JA, Esteba WA, Rivera-Chira M, Monge CC. Hematological parameters in high altitude residents living at 4,355, 4,660, and 5,500 meters above sea level. High Alt Med Biol 2001; 1:97-104. [PMID: 11256567 DOI: 10.1089/15270290050074233] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
There have been a number of reports describing the hematological indicators of Andean residents living at altitudes above 4,000 m, but several confounding factors have made the published results difficult to interpret. To clear up the effect of hypoxia on hemoglobin concentration (Hb, g/dL), hematocrit (Hct, %) and red blood cell concentration (RBC, cells/microL), this publication describes and analyzes these variables in children, men, and women from three large and homogeneous populations living at 4,355 m (n = 151), 4,660 m (n = 400), and 5,500 m (n = 273) in the Southern Peruvian Andes. Hb, Hct, and RBC increase with age in men (p < 0.001), as well as in women (p < 0.001) at the three altitudes of the study. In children (boys and girls) living at 5,500, Hb increases 11% when compared with children living at 4,355 m, and in adults, Hb increases 9.6% when comparing the same altitudes. The maximum percentage increase in Hb with age was 5.6% at 5,500 m, in men and 3.2% at 4,355 m, in women. The average percentage of difference for the Hb concentration between adult men and women is 6.6% at 4,355 m, 9.8% at 4,660 m, and 11.6% at 5,500 m. The differences in Hb concentration between men and women can only be seen after puberty. Finally, Hb is higher in older than younger women, which confirms the role of menopause in the development of erythremia. The result of this analysis reinforces the notion that Hb and Hct seem to be stable and useful parameters for acclimatization only at moderate altitudes; with aging or with increasing altitude, they may become excessive and lose their efficiency to protect the venous oxygen pressure.
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Affiliation(s)
- F León-Velarde
- Cayetano Heredia University/IIA, Department of Physiological Sciences, Lima, Peru.
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León-Velarde F, Rivera-Chira M, Tapia R, Huicho L, Monge-C C. Relationship of ovarian hormones to hypoxemia in women residents of 4,300 m. Am J Physiol Regul Integr Comp Physiol 2001; 280:R488-93. [PMID: 11208579 DOI: 10.1152/ajpregu.2001.280.2.r488] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Prevalence of excessive erythrocytosis, the main sign of chronic mountain sickness (CMS), is greater in postmenopausal Andean women than in premenopausal women. It is uncertain whether this greater prevalence is related to the decline in female hormones and ventilatory function after the occurrence of the menopause. To study this, we compared the physiological variables involved in the physiopathology of CMS [end-tidal CO(2) (PET(CO(2)), Torr) and end-tidal O(2) (PET(O(2)), Torr), arterial oxygen saturation (Sa(O(2)), %), and Hb concentration (g/dl)] and progesterone and estradiol levels between postmenopausal and premenopausal women, both in the luteal and follicular phases. Women residing in Cerro de Pasco (n = 33; 4,300 m) aged 26--62 yr were studied. Postmenopausal women compared with premenopausal women in the luteal phase had lower PET(O(2)) (48 +/- 4 vs. 53 +/- 2 Torr, P = 0.005) and Sa(O(2)) levels (82 +/- 12 vs. 88 +/- 12%, P < 0.005) and higher PET(CO(2)) (34 +/- 2 vs. 29 +/- 3 Torr, P = 0.005) and Hb concentration (19 +/- 1 vs. 14 +/- 2 g/dl, P < 0.005). In addition, plasma progesterone was negatively correlated with PET(CO(2)) and positively correlated with PET(O(2)) and Sa(O(2)). No clear relationship was found among the cycle phases between estradiol and the variables studied. In conclusion, our results reveal that, before menopause, there is better oxygenation and lower Hb levels in women long residing at altitude, and this is associated with higher levels of progesterone in the luteal phase of the cycle.
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Affiliation(s)
- F León-Velarde
- Departamento de Ciencias Fisiológicas/IIA, Universidad Peruana Cayetano Heredia, Apartado 4314, Lima, Perú.
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Joseph V, Soliz J, Pequignot J, Semporé B, Cottet-Emard JM, Dalmaz Y, Favier R, Spielvogel H, Pequignot JM. Gender differentiation of the chemoreflex during growth at high altitude: functional and neurochemical studies. Am J Physiol Regul Integr Comp Physiol 2000; 278:R806-16. [PMID: 10749766 DOI: 10.1152/ajpregu.2000.278.4.r806] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The effect of chronic hypoxia on gender differences in physiology and neurochemistry of chemosensory pathways was studied in prepubertal and adult rats living at sea level (SL; Lyon, France) or at high altitude (HA; La Paz, Bolivia, 3,600 m). HA adult rats had higher hematocrit (Ht%), Hb concentration, resting ventilatory rate (Ve(100)), and higher tyrosine hydroxylase (TH) activity in carotid bodies (CB) than SL animals. At HA and SL, adult females had lower Ht% (46.0 +/- 0.8 vs. 50.4 +/- 0.6% at HA, P < 0.05 and 43.8 +/- 0.9 vs. 47.1 +/- 0.8% at SL, P < 0.05) and Hb (16.1 +/- 0.3 vs. 17.7 +/- 0.2 g/dl at HA, P < 0.05 and 14.5 +/- 0.3 vs. 15.6 +/- 0.1 g/dl at SL, P < 0.05) than males. Females had higher Ve(100) [170 +/- 19 vs. 109 +/- 7 ml. min(-1). 100 g(-1) at HA, P < 0.05 and 50 +/- 3 vs. 40 +/- 2 ml. min(-1). 100 g(-1) at SL, not significant (NS)] and lower CB-TH activity (1.40 +/- 0.2 vs. 3.87 +/- 0.6 pmol/20 min at HA, P < 0.05 and 0.52 +/- 0.1 vs. 0.68 +/- 0.1 pmol/20 min at SL; NS) than males at HA only. The onset of hypoxic ventilatory response during development was delayed at HA. Prepubertal HA females had higher Ve(100) than males (2 wk old, +47%) and higher CB-TH activity (3 wk old, +51%). Medullary noradrenergic groups were sex dimorphic during development at SL. Rats raised at HA had a drop of TH activity between the second and the third postnatal week in all medullary groups. In conclusion, our data support the hypothesis that the CB is the major site for sexual differentiation of the ventilatory control. Ventilatory differences appeared before puberty, and the animals bred at HA had profound alterations in the developmental process of the chemoreflex and its neural pathways. Some of these alterations are under dependence of the sex of the animal, and there is an important interaction between gender and the hypoxic environmental condition during the developmental period.
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Affiliation(s)
- V Joseph
- Laboratoire de Physiologie des Régulations Energétiques, Cellulaires et Moléculaires, Centre National de la Recherche Scientifique et Faculté de Médecine, Université Claude Bernard, Unité Mixte de Recherche 5578, Lyon, France
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