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Ma J, Yin Q, Ye F, Ba Z, Geng H. The efficacy of erythrocyte apheresis for treatment of secondary erythrocytosis: An observational study. Medicine (Baltimore) 2024; 103:e38815. [PMID: 39029086 PMCID: PMC11398752 DOI: 10.1097/md.0000000000038815] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 07/21/2024] Open
Abstract
To evaluate the efficacy of erythrocyte apheresis on the treatment of secondary erythrocytosis. Patients with secondary erythrocytosis who had visited the Department of Hematology at the Qinghai University Affiliated Hospital between January 2021 and May 2022 were enrolled. Based on the treatment method used, the patients were divided into erythrocytapheresis group and bloodletting group. In total, 50 patients were treated using a hemocyte separator and 36 patients were treated with bloodletting. The outcomes of 2 groups were compared. Compared with the bloodletting group, the clinical symptoms improved, blood routine indicators such as RBC, Hb, and HCT significantly reduced, and the progression rate was lower in the erythrocytapheresis group. Erythrocytic apheresis is effective and safe for the treatment of secondary erythrocytosis.
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Affiliation(s)
- Jie Ma
- Department of Hematology, Qinghai University Affiliated Hospital, Xining, China
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Yin R, Wu Y, Li M, Liu C, Pu X, Yi W. Association between high-altitude polycythemia and hypertension: a cross-sectional study in adults at Tibetan ultrahigh altitudes. J Hum Hypertens 2024; 38:555-560. [PMID: 38802600 PMCID: PMC11239486 DOI: 10.1038/s41371-024-00916-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2024] [Revised: 05/03/2024] [Accepted: 05/13/2024] [Indexed: 05/29/2024]
Abstract
The study aimed to evaluate the association between high-altitude polycythemia and hypertension in adults residing on Anduo County's plateau, which is located 4700 meters above sea level. A total of 387 individuals participated in the cross-sectional survey conducted between April and May of 2021. Interviews, physical inspections, and laboratory tests were employed to gather information about all of the subjects. The association between high-altitude polycythemia and hypertension was assessed using multivariable logistic regression models. The average age of the 387 participants was 32.6 ± 6.3 years. Of these participants, 260 (67%) were male. The overall prevalence of hypertension was 27.1% (57/380). When stratified by gender, the prevalence was 12.6% (16/127) in females and 34.2% (89/260) in males. The overall prevalence of high-altitude polycythemia was 19.6% (76/387). When stratified by gender, the prevalence was 26.2% (68/260) in males and 6.3% (8/127) in females. During logistic regression analysis, we found that participants with elevated hemoglobin per 10 g/L had a 26% greater risk of hypertension (adjusting for odds ratio [OR], 1.26; 95% confidence interval [CI], 1.11-1.44). Additionally, high-altitude polycythemia greatly increased the risk of hypertension in comparison to non-high-altitude polycythemia (OR, 3.01; 95% CI, 1.66-5.44, P < 0.001). The consistency of the results was further demonstrated by stratified and interaction analyses, showing that Hans individuals had a higher risk of hypertension. High-altitude polycythemia is positively associated with hypertension in adults residing at Tibetan ultrahigh altitudes. The results of the investigation may aid in the planning of future research and guide the development of targeted healthcare practices for high-altitude populations, particularly among Han Chinese residents of the Tibetan Plateau.
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Affiliation(s)
- Rong Yin
- Department of Nephrology, Hospital of Chengdu Office of People's Government of Tibet Autonomous Region, Chengdu, Sichuan, China
| | - Yunhong Wu
- Department of Endocrinology, Hospital of Chengdu Office of People's Government of Tibet Autonomous Region, Chengdu, Sichuan, China.
| | - Man Li
- Department of Radiology, Hospital of Chengdu Office of People's Government of Tibet Autonomous Region, Chengdu, Sichuan, China
| | - Chunrong Liu
- Intensive Care Unit, Hospital of Chengdu Office of People's Government of Tibet Autonomous Region, Chengdu, Sichuan, China
| | - Xue Pu
- Department of Gastroenterology, Hospital of Chengdu Office of People's Government of Tibet Autonomous Region, Chengdu, Sichuan, China
| | - Wen Yi
- Surgical Unit, Hospital of Chengdu Office of People's Government of Tibet Autonomous Region, Chengdu, Sichuan, China
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Gatterer H, Villafuerte FC, Ulrich S, Bhandari SS, Keyes LE, Burtscher M. Altitude illnesses. Nat Rev Dis Primers 2024; 10:43. [PMID: 38902312 DOI: 10.1038/s41572-024-00526-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/02/2024] [Indexed: 06/22/2024]
Abstract
Millions of people visit high-altitude regions annually and more than 80 million live permanently above 2,500 m. Acute high-altitude exposure can trigger high-altitude illnesses (HAIs), including acute mountain sickness (AMS), high-altitude cerebral oedema (HACE) and high-altitude pulmonary oedema (HAPE). Chronic mountain sickness (CMS) can affect high-altitude resident populations worldwide. The prevalence of acute HAIs varies according to acclimatization status, rate of ascent and individual susceptibility. AMS, characterized by headache, nausea, dizziness and fatigue, is usually benign and self-limiting, and has been linked to hypoxia-induced cerebral blood volume increases, inflammation and related trigeminovascular system activation. Disruption of the blood-brain barrier leads to HACE, characterized by altered mental status and ataxia, and increased pulmonary capillary pressure, and related stress failure induces HAPE, characterized by dyspnoea, cough and exercise intolerance. Both conditions are progressive and life-threatening, requiring immediate medical intervention. Treatment includes supplemental oxygen and descent with appropriate pharmacological therapy. Preventive measures include slow ascent, pre-acclimatization and, in some instances, medications. CMS is characterized by excessive erythrocytosis and related clinical symptoms. In severe CMS, temporary or permanent relocation to low altitude is recommended. Future research should focus on more objective diagnostic tools to enable prompt treatment, improved identification of individual susceptibilities and effective acclimatization and prevention options.
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Affiliation(s)
- Hannes Gatterer
- Institute of Mountain Emergency Medicine, Eurac Research, Bolzano, Italy.
- Institute for Sports Medicine, Alpine Medicine and Health Tourism (ISAG), UMIT TIROL-Private University for Health Sciences and Health Technology, Hall in Tirol, Austria.
| | - Francisco C Villafuerte
- Laboratorio de Fisiología del Transporte de Oxígeno y Adaptación a la Altura - LID, Departamento de Ciencias Biológicas y Fisiológicas, Facultad de Ciencias e Ingeniería, Universidad Peruana Cayetano Heredia, Lima, Perú
| | - Silvia Ulrich
- Department of Respiratory Medicine, University Hospital Zurich, Zurich, Switzerland
| | - Sanjeeb S Bhandari
- Mountain Medicine Society of Nepal, Kathmandu, Nepal
- Emergency Department, UPMC Western Maryland Health, Cumberland, MD, USA
| | - Linda E Keyes
- Department of Emergency Medicine, University of Colorado, Aurora, CO, USA
| | - Martin Burtscher
- Department of Sport Science, University of Innsbruck, Innsbruck, Austria
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Ortiz-Saavedra B, Montes-Madariaga ES, Moreno-Loaiza O, Toro-Huamanchumo CJ. Hypertension subtypes at high altitude in Peru: Analysis of the Demographic and Family Health Survey 2016-2019. PLoS One 2024; 19:e0300457. [PMID: 38608222 PMCID: PMC11014732 DOI: 10.1371/journal.pone.0300457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Accepted: 02/27/2024] [Indexed: 04/14/2024] Open
Abstract
BACKGROUND The prevalence of hypertension in Peru has increased over the years. Approximately one third of the Peruvian population lives at high altitudes. This population presents particular physiological, genetic and environmental characteristics that could be related to the prevalence of hypertension and its subtypes. OBJECTIVE To assess the association between altitude and hypertension in the Peruvian population through an analysis of a nationally representative survey. METHODS We conducted a cross-sectional analysis of the Demographic and Family Health Survey for the period 2016-2019. We included 122,336 individuals aged 18 years and older. Hypertension was defined according to the JNC-7 guidelines. High-altitude location was defined as a residential cluster located above 2,500 meters above sea level. We utilized generalized linear models from the Poisson family with a log-link function to assess the magnitude of the association between high altitude and hypertension. Additionally, we employed multinomial regression models to analyze the association between high altitude and subtypes of hypertension, including isolated systolic hypertension (ISH), isolated diastolic hypertension (IDH), and systolic-diastolic hypertension (SDH). RESULTS In the adjusted Poisson regression model, we found that the prevalence of hypertension among participants living at high altitudes was lower compared to those living at low altitudes (aPR: 0.89; 95% CI: 0.86-0.93). In the adjusted multinomial regression model, we observed a lower prevalence rate of ISH among participants residing at high altitudes (aRPR: 0.68; 95% CI: 0.61-0.73) and a higher prevalence rate of IDH among participants residing at high altitudes (aRPR: 1.60; 95% CI: 1.32-1.94). CONCLUSIONS Residents at high altitudes in Peru have a lower prevalence rate of ISH and a higher prevalence rate of IDH compared to those living at low altitudes. Further studies are needed to determine the influence of other biological, environmental, and healthcare access factors on this relationship.
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Affiliation(s)
| | | | - Oscar Moreno-Loaiza
- Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, Brasil
| | - Carlos J. Toro-Huamanchumo
- Unidad de Investigación para la Generación y Síntesis de Evidencias en Salud, Universidad San Ignacio de Loyola, Lima, Peru
- OBEMET Center for Obesity and Metabolic Health, Lima, Peru
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Vilca Coaquira KM, Rojas Chambilla RA, Tejada Flores J, Tintaya Ramos HO, Quispe Trujillo MM, Quispe Humpiri SA, Calisaya Huacasi ÁG, Pino Vanegas YM, Peña Vicuña GF, Salazar Granara AA, Tacuna Calderon AL, Garcia Bedoya NM, Yang M, Hancco Zirena I. Lower glycemia levels in subjects with excessive erythrocytosis during the oral glucose tolerance test living in conditions of severe hypoxia. Front Physiol 2024; 15:1387132. [PMID: 38655033 PMCID: PMC11035787 DOI: 10.3389/fphys.2024.1387132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Accepted: 03/20/2024] [Indexed: 04/26/2024] Open
Abstract
Background Previous studies showed that residents of higher elevations have lower glucose levels. Our objective in this study is to determine the basal and postprandial glucose levels in apparently healthy permanent residents of the miner population center of La Rinconada located 5100 meters (m) above sea level. Method Forty male permanent residents of the Rinconada miner population center were studied. The oral glucose tolerance test was used to evaluate basal and postprandial glycemia levels at 1, 2, and 3 h. Results The individuals had a mean age of 43.95 ± 8.54 years. Basal glycemia in subjects without excessive erythrocytosis (EE) was 73.3 ± 7.9 mg/dL, while levels in patients with EE were 57.98 ± 7.38 mg/dL. In the postprandial period, at 1 h after oral glucose overload, a mean value of 76.35 ± 13.53 mg/dL was observed in subjects with EE compared to 94.68 ± 9.98 mg/dL in subjects without EE. After 2 h, subjects with EE had a glycemia level of 72.91 ± 9.17 mg/dL EE compared to 90.73 ± 13.86 mg/dL without EE. At 3 h, the average glycemia level in subjects with EE was 70.77 ± 8.73 mg/dL compared to 87.79 ± 14.16 mg/dL in those without EE. Conclusion These findings suggest that under hypoxic conditions, glycemia levels are lower in both subjects with and without EE, having obtained lower levels in subjects with EE in relation to those with normal values of Hb and Hct. The results of this study indicate that in the conditions of severe hypoxia, blood glucose levels are below the values considered normal for sea level.
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Affiliation(s)
| | | | - Jeancarlo Tejada Flores
- Facultad de Medicina Humana, Universidad Nacional Del Altiplano, Puno, Perú
- ACEM UNA, Puno, Perú
| | | | | | | | | | - Yony M. Pino Vanegas
- Facultad De Educación, Escuela Profesional De Educación Física, UNA Puno, Puno, Perú
| | | | | | - Ana Lucia Tacuna Calderon
- Instituto De Investigación en Medicina De Altura (CIMA), Facultad De Medicina Humana, Universidad De San Martín De Porres, Lima, Perú
| | | | - Moua Yang
- Division of Hemostasis and Thrombosis, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, United States
| | - Ivan Hancco Zirena
- Instituto De Investigación en Medicina De Altura (CIMA), Facultad De Medicina Humana, Universidad De San Martín De Porres, Lima, Perú
- Division of Hemostasis and Thrombosis, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, United States
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Guo Y, Liu X, Zhang Q, Shi Z, Zhang M, Chen J. Can acute high-altitude sickness be predicted in advance? REVIEWS ON ENVIRONMENTAL HEALTH 2024; 39:27-36. [PMID: 36165715 DOI: 10.1515/reveh-2022-0117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 09/02/2022] [Indexed: 06/16/2023]
Abstract
In high-altitude environments, the oxygen and air density are decreased, and the temperature and humidity are low. When individuals enter high-altitude areas, they are prone to suffering from acute mountain sickness (AMS) because they cannot tolerate hypoxia. Headache, fatigue, dizziness, and gastrointestinal reactions are the main symptoms of AMS. When these symptoms cannot be effectively alleviated, they can progress to life-threatening high-altitude pulmonary edema or high-altitude cerebral edema. If the risk of AMS can be effectively assessed before people enter high-altitude areas, then the high-risk population can be promptly discouraged from entering the area, or drug intervention can be established in advance to prevent AMS occurrence and avoid serious outcomes. This article reviews recent studies related to the early-warning biological indicators of AMS to provide a new perspective on the prevention of AMS.
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Affiliation(s)
- Yan Guo
- Medical College of Soochow University, Suzhou, Jiangsu Province, China
- Department of Pathology, Qinghai Provincial People's Hospital, Xining, Qinghai Province, China
| | - Xiao Liu
- Department of Basic Medical Sciences, The 960th Hospital of PLA, Jinan, Shandong Province, China
| | - Qiang Zhang
- Department of Neurosurgery, Qinghai Provincial People's Hospital, Xining, Qinghai Province, China
| | - Zhongshan Shi
- Department of Intensive Care Medicine, Ge er mu People's Hospital, Ge er mu, Qinghai Province, China
| | - Menglan Zhang
- Department of Pathology, Qinghai Provincial People's Hospital, Xining, Qinghai Province, China
| | - Jie Chen
- Department of Pathology, Qinghai Provincial People's Hospital, Xining, Qinghai Province, China
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Richalet JP, Hermand E, Lhuissier FJ. Cardiovascular physiology and pathophysiology at high altitude. Nat Rev Cardiol 2024; 21:75-88. [PMID: 37783743 DOI: 10.1038/s41569-023-00924-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 08/16/2023] [Indexed: 10/04/2023]
Abstract
Oxygen is vital for cellular metabolism; therefore, the hypoxic conditions encountered at high altitude affect all physiological functions. Acute hypoxia activates the adrenergic system and induces tachycardia, whereas hypoxic pulmonary vasoconstriction increases pulmonary artery pressure. After a few days of exposure to low oxygen concentrations, the autonomic nervous system adapts and tachycardia decreases, thereby protecting the myocardium against high energy consumption. Permanent exposure to high altitude induces erythropoiesis, which if excessive can be deleterious and lead to chronic mountain sickness, often associated with pulmonary hypertension and heart failure. Genetic factors might account for the variable prevalence of chronic mountain sickness, depending on the population and geographical region. Cardiovascular adaptations to hypoxia provide a remarkable model of the regulation of oxygen availability at the cellular and systemic levels. Rapid exposure to high altitude can have adverse effects in patients with cardiovascular diseases. However, intermittent, moderate hypoxia might be useful in the management of some cardiovascular disorders, such as coronary heart disease and heart failure. The aim of this Review is to help physicians to understand the cardiovascular responses to hypoxia and to outline some recommendations that they can give to patients with cardiovascular disease who wish to travel to high-altitude destinations.
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Affiliation(s)
- Jean-Paul Richalet
- Hypoxie et Poumon, Université Sorbonne Paris Nord, INSERM U1272, Paris, France.
| | - Eric Hermand
- Unité de Recherche Pluridisciplinaire Sport Santé Société, ULR 7369-URePSSS, Université Littoral Côte d'Opale, Université Artois, Université Lille, CHU Lille, Dunkirk, France
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Liu X, Yang C, Zhang X, Ye R, Li X, Zhang Z, Jia S, Sun L, Meng Q, Chen X. Association between hemoglobin concentration and hypertension risk in native Tibetans at high altitude. J Clin Hypertens (Greenwich) 2024; 26:17-23. [PMID: 37724706 PMCID: PMC10795086 DOI: 10.1111/jch.14726] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Revised: 09/03/2023] [Accepted: 09/04/2023] [Indexed: 09/21/2023]
Abstract
Previous studies examining the association between hemoglobin concentration and hypertension have yielded inconsistent results. There is still a lack of evidence regarding the association between hemoglobin concentration and hypertension risk in native Tibetans at high altitude. We performed this cross-sectional study in Luhuo County of Ganzi Tibetan Autonomous Prefecture (average altitude of 3500 m). In this study, we enrolled 1547 native Tibetans. The association between hemoglobin concentration and hypertension risk was examined by multivariate binary logistic regression and smooth curve fitting. Native Tibetans with hypertension had significantly higher hemoglobin concentrations than those without hypertension (165.9 ± 21.5 g/L vs. 157.7 ± 19.2 g/L, P < 0.001). An increase in hemoglobin concentration of 1 g/L was associated with hypertension (odds ratio [OR] 1.02, 95% confidence interval [CI] 1.01-1.02) after confounder adjustment. The highest hemoglobin concentration group (exceeding 173 g/L) was associated with an increased hypertension risk compared with the bottom quartile of hemoglobin concentration (OR 2.39, 95% CI 1.48-3.85). Hemoglobin concentration (per 1 g/L change) exceeding 176 g/L was significantly associated with an increased hypertension risk (OR 1.04, 95% CI 1.03-1.06). Additionally, high-altitude polycythemia significantly increased the hypertension risk compared with a normal hemoglobin concentration (OR 2.92, 95% CI 1.25-6.86). A similar result was observed for mild polycythemia (OR 1.74, 95% CI 1.29-2.34). In conclusion, hemoglobin concentration was associated with hypertension risk in native Tibetans. When the hemoglobin concentration exceeded a certain value (approximately 176 g/L), the risk of hypertension was significantly increased.
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Affiliation(s)
- Xueting Liu
- Department of CardiologyWest China Hospital of Sichuan UniversityChengduChina
| | - Changqiang Yang
- Department of CardiologyWest China Hospital of Sichuan UniversityChengduChina
| | - Xin Zhang
- Department of CardiologyWest China Hospital of Sichuan UniversityChengduChina
| | - Runyu Ye
- Department of CardiologyWest China Hospital of Sichuan UniversityChengduChina
| | - Xinran Li
- Department of CardiologyWest China Hospital of Sichuan UniversityChengduChina
| | - Zhipeng Zhang
- Department of CardiologyWest China Hospital of Sichuan UniversityChengduChina
| | - Shanshan Jia
- Department of CardiologyWest China Hospital of Sichuan UniversityChengduChina
| | - Lirong Sun
- Department of CardiologyWest China Hospital of Sichuan UniversityChengduChina
| | - Qingtao Meng
- Department of CardiologyWest China Hospital of Sichuan UniversityChengduChina
| | - Xiaoping Chen
- Department of CardiologyWest China Hospital of Sichuan UniversityChengduChina
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Zila-Velasque JP, Soriano-Moreno DR, Medina-Ramirez SA, Ccami-Bernal F, Castro-Diaz SD, Cortez-Soto AG, Esparza Varas AL, Fernandez-Morales J, Olortegui-Rodriguez JJ, Pelayo-Luis IP, Zafra-Tanaka JH. Prevalence of hypertension in adults living at altitude in Latin America and the Caribbean: A systematic review and meta-analysis. PLoS One 2023; 18:e0292111. [PMID: 37824544 PMCID: PMC10569637 DOI: 10.1371/journal.pone.0292111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Accepted: 09/13/2023] [Indexed: 10/14/2023] Open
Abstract
OBJECTIVE The objective of this systematic review and meta-analysis was to assess the prevalence of hypertension in populations living at altitude in Latin America and the Caribbean. METHODS We conducted a systematic search from January 1, 2000 to January 10, 2023 in Web of Science (WoS)/Core Collection, WoS/Medline, WoS/Scielo, Scopus, PubMed and Embase databases. We included studies that assessed the prevalence of hypertension in altitude populations (>1500 m.a.s.l.) and these were meta-analyzed using a random-effects model. To assess the sources of heterogeneity, we performed subgroup and meta-regression analyses. RESULTS Thirty cross-sectional studies (117 406 participants) met the inclusion criteria. Studies used different cut-off points. The prevalence of hypertension in the studies that considered the cut-off point of ≥ 140/90 mmHg in the general population was 19.1%, ≥ 130/85 mmHg was 13.1%, and ≥ 130/80 mmHg was 43.4%. There was a tendency for the prevalence of hypertension to be higher in men. In meta-regression analyses, no association was found between altitude, mean age, year of publication, risk of bias and prevalence of hypertension. CONCLUSION The prevalence of hypertension in the altitude population of Latin America and the Caribbean is lower than that reported in populations living at sea level and lower than other altitude populations such as Tibetans. PROSPERO CRD42021275229.
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Affiliation(s)
- J. Pierre Zila-Velasque
- Facultad de Medicina Humana, Universidad Nacional Daniel Alcides Carrion, Pasco, Peru
- Red Latinoamericana de Medicina en Altitud e Investigacion (REDLAMAI), Pasco, Peru
| | - David R. Soriano-Moreno
- Unidad de Investigación Clínica y Epidemiológica, Escuela de Medicina, Universidad Peruana Unión, Lima, Peru
| | - Sebastian A. Medina-Ramirez
- Unidad de Investigación Clínica y Epidemiológica, Escuela de Medicina, Universidad Peruana Unión, Lima, Peru
| | - Fabricio Ccami-Bernal
- Facultad de Medicina, Universidad Nacional de San Agustin de Arequipa, Arequipa, Peru
| | - Sharong D. Castro-Diaz
- Unidad de Investigación Clínica y Epidemiológica, Escuela de Medicina, Universidad Peruana Unión, Lima, Peru
| | - Andrea G. Cortez-Soto
- Sociedad Científica de Estudiantes de Medicina de Ica, Universidad Nacional San Luis Gonzaga, Ica, Peru
| | - Analis L. Esparza Varas
- Universidad Nacional de Trujillo, La Libertad, Peru
- Sociedad científica de estudiantes de medicina de la Universidad Nacional de Trujillo, Trujillo, Peru
| | - Jared Fernandez-Morales
- Unidad de Investigación Clínica y Epidemiológica, Escuela de Medicina, Universidad Peruana Unión, Lima, Peru
| | - Juan J. Olortegui-Rodriguez
- Unidad de Investigación Clínica y Epidemiológica, Escuela de Medicina, Universidad Peruana Unión, Lima, Peru
| | - Isabel P. Pelayo-Luis
- Unidad de Investigación Clínica y Epidemiológica, Escuela de Medicina, Universidad Peruana Unión, Lima, Peru
- Escuela de Enfermería, Universidad Peruana Unión, Lima, Peru
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Day TA, Wilson RJA. An apparent paradox across the time course and magnitude of oxygen sensing in humans - is a 'one-size-fits-all' hypoxic response up in the air? J Physiol 2023; 601:4245-4247. [PMID: 37712578 DOI: 10.1113/jp285341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/16/2023] Open
Affiliation(s)
- Trevor A Day
- Department of Biology, Faculty of Science and Technology, Mount Royal University, Calgary, AB, Canada
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Richard J A Wilson
- Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
- Hotchkiss Brain Institute and Alberta Children's Hospital Research Institute, University of Calgary, Calgary, AB, Canada
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11
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Sukun A, Önal C. Factors Affecting Carotid Artery Stenosis in the Elderly Living at High Altitudes. Cureus 2023; 15:e47048. [PMID: 37846346 PMCID: PMC10576857 DOI: 10.7759/cureus.47048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/15/2023] [Indexed: 10/18/2023] Open
Abstract
BACKGROUND Factors affecting carotid artery stenosis have been generally investigated. However, considering the protective effect of altitude, studies on elderly individuals at high altitudes are few. Our aim is to investigate the systematic adaptive changes caused by high-altitude exposure through the causes of carotid artery stenosis. MATERIALS AND METHODS Carotid Doppler ultrasound was performed on 250 patients over the age of 50 years. The patients' age, gender, height, weight, smoking history, place of residence, and presence of comorbidities were questioned. Those with diabetes, hypertension, hyperlipidemia, and coronary disease were excluded from the study. Those who did not reside at high altitudes were excluded from the study. One hundred and thirty-five patients were included in the study. Carotid artery Doppler findings and biochemical parameters were recorded. Factors affecting stenosis in the carotid arteries were compared. RESULTS In our study, the factors affecting carotid stenosis were determined to be age, gender, presence of plaque, plaque type, and mean carotid intima-media thickness (CIMT). The mean CIMT of the patients was calculated as 0.71±0.14 mm. The mean CIMT measurement level was significantly higher in patients with plaque in the carotid artery (p<0.05). According to receiver operating characteristic curves, CIMT values higher than 0.72 mm increase plaque and stenosis formation in the common carotid artery (CCA) and internal carotid artery (ICA) in elderly people living at high altitudes (p<0.05, area under the curve [AUC]: 0.71-0.83). CONCLUSIONS The most important factors affecting carotid stenosis in individuals living at high altitudes are age, gender, CIMT, plaque, and plaque type. When soft plaques were detected, the risk of stenosis was found to be higher than in calcific plaques. Additionally, the number of factors affecting stenosis was greater on the left (ICA). This suggests that the left carotid system is more vulnerable. It can be said that in elderly individuals living at high altitudes, a CIMT higher than 0.72 mm is a cutoff value in the presence of plaque and stenosis in the carotid arteries.
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Affiliation(s)
- Abdullah Sukun
- Radiology, Baskent University Alanya Research and Application Center, Antalya, TUR
| | - Canver Önal
- Radiology, Kars Harakani State Hospital, Kars, TUR
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Peng W, Li H, Xia C, Guo Y, Xu X, Zeng W, Liu K, Che Q, Jiang Y, Xiang K, Zhou X, Li G, Li Z. Cardiovascular indicators associated with ventricular remodeling in chronic high-altitude disease: a cardiovascular MRI study. Eur Radiol 2023; 33:6267-6277. [PMID: 37036481 DOI: 10.1007/s00330-023-09574-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 02/06/2023] [Accepted: 02/09/2023] [Indexed: 04/11/2023]
Abstract
OBJECTIVE This study aimed to assess biventricular function and mechanics in patients with the chronic high-altitude disease (CHAD) using cardiovascular MRI and explore the possible risk factors associated with ventricular remodeling. METHODS In this prospective study, consecutive CHAD patients and healthy controls at high-altitude (HA) and at sea level (SL) underwent cardiovascular MRI. Right ventricular (RV) and left ventricular (LV) function and global strain parameters were compared. To identify risk factors associated with ventricular remodeling, multiple linear regression analyses were used. RESULTS A total of 33 patients with CHAD (42.97 years ± 11.80; 23 men), 33 HA (41.18 years ± 8.58; 21 men), and 33 SL healthy controls (43.48 years ± 13.40; 21 men) were included. A Significantly decreased biventricular ejection fraction was observed in patients (all p < 0.05). Additionally, the HA group displayed lower magnitudes of biventricular longitudinal peak strain (PS) (RV, - 13.67% ± 4.05 vs. - 16.22% ± 3.03; LV, - 14.68% ± 2.20 vs. - 16.19% ± 2.51; both p < 0.05), but a higher LV circumferential PS (- 20.74% ± 2.02 vs. - 19.17% ± 2.34, p < 0.05) than the SL group. Moreover, multiple linear regression analyses revealed that HGB (β = 0.548) was related to the LV remodeling index, whereas BUN (β = 0.570) was associated with the RV remodeling index. CONCLUSIONS With the deterioration of RV function in patients with CHAD, LV function was also impaired concomitantly. Hypoxia-induced erythrocytosis may contribute to LV impairment, while BUN was considered an independent risk factor for RV remodeling. KEY POINTS • A significantly lower biventricular ejection fraction was observed in patients, with a decreased magnitude of left ventricular (LV) peak systolic strain rate (radial and circumferential) and peak diastolic strain rate (all p < 0.05). • High-altitude healthy natives showed a lower biventricular longitudinal peak strain (all p < 0.05). • Hemoglobin was related to LV remodeling (β = 0.548), while BUN (β = 0.570) was independently associated with RV remodeling in CHAD patients.
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Affiliation(s)
- Wanlin Peng
- Department of Radiology, West China Hospital, Sichuan University, 37# Guo Xue Xiang, Chengdu, 610041, Sichuan, China
| | - Hongwei Li
- Department of Cardiology, Hospital of Chengdu Office of People's Government of Tibetan Autonomous Region, 20# Ximianqiao Street, Chengdu, 610041, Sichuan, China
| | - Chunchao Xia
- Department of Radiology, West China Hospital, Sichuan University, 37# Guo Xue Xiang, Chengdu, 610041, Sichuan, China.
| | - Yingkun Guo
- Department of Radiology, West China Second University Hospital, Sichuan University, 20# South ren Min Road, Chengdu, 610041, Sichuan, China
- Key Laboratory of Obstetric & Gynecologic and Pediatric Diseases and Birth Defects of Ministry of Education, West China Second University Hospital, Sichuan University, 20# South Ren Min Road, Chengdu, 610041, Sichuan, China
| | - Xu Xu
- Department of Radiology, West China Hospital, Sichuan University, 37# Guo Xue Xiang, Chengdu, 610041, Sichuan, China
| | - Wen Zeng
- Department of Radiology, West China Hospital, Sichuan University, 37# Guo Xue Xiang, Chengdu, 610041, Sichuan, China
| | - Keling Liu
- Department of Radiology, West China Hospital, Sichuan University, 37# Guo Xue Xiang, Chengdu, 610041, Sichuan, China
| | - Qianqiu Che
- Department of Cardiology, Hospital of Chengdu Office of People's Government of Tibetan Autonomous Region, 20# Ximianqiao Street, Chengdu, 610041, Sichuan, China
| | - Yuexin Jiang
- Department of Radiology, Hospital of Chengdu Office of People's Government of Tibetan Autonomous Region, 20# Ximianqiao Street, Chengdu, 610041, Sichuan, China
| | - Kejin Xiang
- Department of Radiology, Hospital of Chengdu Office of People's Government of Tibetan Autonomous Region, 20# Ximianqiao Street, Chengdu, 610041, Sichuan, China
| | - Xiaoyue Zhou
- MR Collaboration, Siemens Healthineers Ltd., Shanghai, 200126, China
| | - Gang Li
- Department of Radiology, The People's Hospital of Ningnan County Sichuan Province, Ningnan, 615400, Sichuan, China
| | - Zhenlin Li
- Department of Radiology, West China Hospital, Sichuan University, 37# Guo Xue Xiang, Chengdu, 610041, Sichuan, China.
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13
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Ma Y, Hou J, Huang D, Zhang Y, Liu Z, Tian M. Expression of protein phosphatase 4 in different tissues under hypoxia. INDIAN J PATHOL MICR 2023; 66:577-583. [PMID: 37530343 DOI: 10.4103/ijpm.ijpm_1179_21] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/03/2023] Open
Abstract
Relevant research data shows that there is a certain degree of energy metabolism imbalance in highland residents. Protein phosphatase 4 (PP4) has been found as a new factor in the regulation of sugar and lipid metabolism. Here, we investigate the differential expression of PP4 at a simulated altitude of 4,500 m in the heart, lung, and brain tissues of rats. A hypoxic plateau rat model was established using an animal decompression chamber. A blood routine test was performed by an animal blood cell analyzer on rats cultured for different hypoxia periods at 4,500 m above sea level. Quantitative polymerase chain reaction (qPCR) and western blot were used to detect the changes of protein phosphatase 4 catalytic subunit (PP4C) gene and protein in heart, lung, and brain tissues. The PP4C gene with the highest expression level found in rats slowly entering the high altitude area (20 m-2200 m-7 d-4500 m-3 d) was about twice as high as the low elevation group (20 m above sea level). The simulated high-altitude hypoxia induced an increase of PP4C expression level in all tissues, and the expression in the lung tissue was twice as expressed as heart and brain tissue at high altitude (P < 0.05). These results suggest that the PP4 phosphatase complex is ubiquitously expressed in rat tissues and likely involved in adaptation to or disease associated with high-altitude hypoxia.
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Affiliation(s)
- Yanyan Ma
- Central Laboratory, Affiliated Hospital of Qinghai University, Tongren Road 29, Qinghai Province; Medical College of Qinghai University, Xining, Qinghai Province, China
| | - Jing Hou
- Central Laboratory, Affiliated Hospital of Qinghai University, Tongren Road 29, Qinghai Province, China
| | - Dengliang Huang
- Central Laboratory, Affiliated Hospital of Qinghai University, Tongren Road 29, Qinghai Province, China
| | - Yaogang Zhang
- Central Laboratory, Affiliated Hospital of Qinghai University, Tongren Road 29, Qinghai Province, China
| | - Zhe Liu
- Central Laboratory, Affiliated Hospital of Qinghai University, Tongren Road 29, Qinghai Province, China
| | - Meiyuan Tian
- Central Laboratory, Affiliated Hospital of Qinghai University, Tongren Road 29, Qinghai Province; Medical College of Qinghai University, Xining, Qinghai Province, China
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Wang S, Ma J, Qiu H, Liu S, Zhang S, Liu H, Zhang P, Ge RL, Li G, Cui S. Plasma exosomal microRNA expression profiles in patients with high-altitude polycythemia. Blood Cells Mol Dis 2023; 98:102707. [DOI: 10.1016/j.bcmd.2022.102707] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2022] [Revised: 10/19/2022] [Accepted: 10/26/2022] [Indexed: 11/06/2022]
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15
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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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16
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Perger E, Baillieul S, Esteve F, Pichon A, Bilo G, Soranna D, Doutreleau S, Savina Y, Ulliel-Roche M, Brugniaux JV, Stauffer E, Oberholzer L, Howe C, Hannco I, Lombardi C, Tamisier R, Pepin JL, Verges S, Parati G. Nocturnal hypoxemia, blood pressure, vascular status and chronic mountain sickness in the highest city in the world. Ann Med 2022; 54:1884-1893. [PMID: 35786084 PMCID: PMC9258438 DOI: 10.1080/07853890.2022.2091791] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
INTRODUCTION Chronic mountain sickness (CMS) is a condition characterized by excessive erythrocytosis in response to chronic hypobaric hypoxia. CMS frequently triggers cardiorespiratory diseases such as pulmonary hypertension and right or left heart failure. Ambient hypoxia might be further amplified night-time by intermittent hypoxia related to sleep-disordered breathing (SDB) so that sleep disturbance may be an important feature of CMS. Our aim was to characterize in a cross-sectional study nocturnal hypoxaemia, SDB, blood pressure (BP), arterial stiffness and carotid intima-media thickness (CIMT) in highlanders living at extreme altitude. METHODS Men aged 18 to 55 years were prospectively recruited. Home sleep apnoea test, questionnaires (short-form health survey; Montreal cognitive assessment; Pittsburgh Sleep Questionnaire Index and the Insomnia severity index), 24-h ambulatory BP monitoring, CIMT and arterial stiffness were evaluated in 3 groups: i) Andean lowlanders (sea-level); ii) highlanders living at 3,800 m and iii) highlanders living at 5,100 m. Analyses were conducted in sub-groups according to 1) CMS severity 2) healthy subjects living at the three different altitude. RESULTS Ninety-two males were evaluated at their living altitudes. Among the 54 highlanders living at 5,100 m, subjects with CMS showed lower mean nocturnal oxygen saturation (SpO2), SpO2 nadir, lower pulse wave velocity and higher nocturnal BP variability than those with no-CMS. Lower nocturnal SpO2 nadir was associated with higher CMS severity (ß= -0.14, p=.009). Among the 55 healthy subjects, healthy highlanders at 5,100 m were characterized by lower scores on quality of life and sleep quality scales and lower mean SpO2 compared to lowlanders. CONCLUSIONS Lower nocturnal SpO2 and higher nocturnal BP variability are associated with CMS severity in individuals living permanently at high altitude. The role of lower SpO2 and higher nocturnal BP variability in the cardiovascular progression of CMS and in the overall prognosis of the disease need to be evaluated in further studies.
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Affiliation(s)
- Elisa Perger
- Istituto Auxologico Italiano, IRCCS, Sleep Disorders Center & Department of Cardiovascular, Neural and Metabolic Sciences, San Luca Hospital, Milan, Italy.,Biostatistic Unit, University of Milano-Bicocca, Milan, Italy
| | - Sébastien Baillieul
- Univ. Grenoble Alpes, HP2 Laboratory, INSERM U1300, CHU Grenoble Alpes, Grenoble, France
| | - François Esteve
- Inserm UA7, Rayonnement Synchrotron pour la Recherche Biomédicale, Grenoble, France
| | - Aurélien Pichon
- Faculty of Sport Sciences, Université de Poitiers, Laboratory Mobility, aging & exercise (MOVE, EA6314), Poitiers, France
| | - Gzregorz Bilo
- Istituto Auxologico Italiano, IRCCS, Sleep Disorders Center & Department of Cardiovascular, Neural and Metabolic Sciences, San Luca Hospital, Milan, Italy.,Biostatistic Unit, University of Milano-Bicocca, Milan, Italy
| | - Davide Soranna
- Istituto Auxologico Italiano, IRCCS, Biostatistics unit, Milan, Italy
| | - Stéphane Doutreleau
- Univ. Grenoble Alpes, HP2 Laboratory, INSERM U1300, CHU Grenoble Alpes, Grenoble, France
| | - Yann Savina
- Univ. Grenoble Alpes, HP2 Laboratory, INSERM U1300, CHU Grenoble Alpes, Grenoble, France
| | - Mathilde Ulliel-Roche
- Univ. Grenoble Alpes, HP2 Laboratory, INSERM U1300, CHU Grenoble Alpes, Grenoble, France
| | - Julien V Brugniaux
- Univ. Grenoble Alpes, HP2 Laboratory, INSERM U1300, CHU Grenoble Alpes, Grenoble, France
| | - Emeric Stauffer
- Interuniversity Laboratory of Human Movement Biology (LIBM, EA7424), "Red Blood cell and Vascular Biology" team, Univ Lyon - University Claude Bernard Lyon 1, Villeurbanne, France
| | - Laura Oberholzer
- Department of Physical Performance, Norwegian School of Sport Sciences, Oslo, Norway
| | - Connor Howe
- Centre for Heart, Lung, and Vascular Health, University of British Columbia, Kelowna, Canada
| | - Ivan Hannco
- Univ. Grenoble Alpes, HP2 Laboratory, INSERM U1300, CHU Grenoble Alpes, Grenoble, France
| | - Carolina Lombardi
- Istituto Auxologico Italiano, IRCCS, Sleep Disorders Center & Department of Cardiovascular, Neural and Metabolic Sciences, San Luca Hospital, Milan, Italy.,Biostatistic Unit, University of Milano-Bicocca, Milan, Italy
| | - Renaud Tamisier
- Univ. Grenoble Alpes, HP2 Laboratory, INSERM U1300, CHU Grenoble Alpes, Grenoble, France
| | - Jean-Louis Pepin
- Univ. Grenoble Alpes, HP2 Laboratory, INSERM U1300, CHU Grenoble Alpes, Grenoble, France
| | - Samuel Verges
- Univ. Grenoble Alpes, HP2 Laboratory, INSERM U1300, CHU Grenoble Alpes, Grenoble, France
| | - Gianfranco Parati
- Istituto Auxologico Italiano, IRCCS, Sleep Disorders Center & Department of Cardiovascular, Neural and Metabolic Sciences, San Luca Hospital, Milan, Italy.,Biostatistic Unit, University of Milano-Bicocca, Milan, Italy
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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: 17] [Impact Index Per Article: 8.5] [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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18
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Prevalence of hypertension and its relationship with altitude in highland areas: a systematic review and meta-analysis. Hypertens Res 2022; 45:1225-1239. [PMID: 35705740 DOI: 10.1038/s41440-022-00955-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Revised: 05/12/2022] [Accepted: 05/13/2022] [Indexed: 02/05/2023]
Abstract
This systematic review and meta-analysis synthesized the pooled prevalence of hypertension at high altitudes and explored its correlation with altitude using studies published in Chinese and English from database inception to February 2021. A systematic literature search was conducted among bibliographic databases (PubMed, Embase, and Web of Science) and three Chinese databases (CNKI, VIP, and Wanfang data) to identify eligible studies. A random-effects model was used to calculate the overall pooled prevalence of hypertension. The I2 statistic was used to assess heterogeneity across studies. Random-effects meta-regression was conducted to investigate covariates that may have influenced between-study heterogeneity. The pooled prevalence of hypertension among the general population in high-altitude areas was 33.0% (95% CI: 29.0-38.0%), with high between-study heterogeneity (I2 = 99.4%, P < 0.01). Subgroup analyses showed the pooled prevalence of hypertension in Tibetan individuals was significantly higher than that in non-Tibetan individuals living in the Himalayas and Pamir Mountains (41% vs. 18%). A trend toward an increase in the prevalence of hypertension was found with every 100-m increase in elevation (coefficient: 0.012, 95% CI: -0.001 to 0.025, P = 0.069) only in Tibetan individuals. In addition, in these individuals, we found an increase in mean diastolic BP with each 100-m increase in altitude (coefficient: 0.763, 95% CI: 0.122-1.403, P = 0.025). Our meta-analysis suggests that the pooled prevalence of hypertension among the general population in high-altitude areas is 33.0%. Subjects of Tibetan ethnicity were more prone to developing hypertension at high altitudes. However, a very weak relationship between altitude and the prevalence of hypertension was found only in Tibetan individuals.
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19
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Leiva O, Hobbs G, Ravid K, Libby P. Cardiovascular Disease in Myeloproliferative Neoplasms: JACC: CardioOncology State-of-the-Art Review. JACC CardioOncol 2022; 4:166-182. [PMID: 35818539 PMCID: PMC9270630 DOI: 10.1016/j.jaccao.2022.04.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 04/19/2022] [Accepted: 04/22/2022] [Indexed: 11/24/2022] Open
Abstract
Myeloproliferative neoplasms are associated with increased risk for thrombotic complications. These conditions most commonly involve somatic mutations in genes that lead to constitutive activation of the Janus-associated kinase signaling pathway (eg, Janus kinase 2, calreticulin, myeloproliferative leukemia protein). Acquired gain-of-function mutations in these genes, particularly Janus kinase 2, can cause a spectrum of disorders, ranging from clonal hematopoiesis of indeterminate potential, a recently recognized age-related promoter of cardiovascular disease, to frank hematologic malignancy. Beyond thrombosis, patients with myeloproliferative neoplasms can develop other cardiovascular conditions, including heart failure and pulmonary hypertension. The authors review the pathophysiologic mechanisms of cardiovascular complications of myeloproliferative neoplasms, which involve inflammation, prothrombotic and profibrotic factors (including transforming growth factor-beta and lysyl oxidase), and abnormal function of circulating clones of mutated leukocytes and platelets from affected individuals. Anti-inflammatory therapies may provide cardiovascular benefit in patients with myeloproliferative neoplasms, a hypothesis that requires rigorous evaluation in clinical trials.
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Key Words
- ASXL1, additional sex Combs-like 1
- CHIP, clonal hematopoiesis of indeterminate potential
- DNMT3a, DNA methyltransferase 3 alpha
- IL, interleukin
- JAK, Janus-associated kinase
- JAK2, Janus kinase 2
- LOX, lysyl oxidase
- MPL, myeloproliferative leukemia protein
- MPN, myeloproliferative neoplasm
- STAT, signal transducer and activator of transcription
- TET2, tet methylcytosine dioxygenase 2
- TGF, transforming growth factor
- atherosclerosis
- cardiovascular complications
- clonal hematopoiesis
- myeloproliferative neoplasms
- thrombosis
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Affiliation(s)
- Orly Leiva
- Division of Cardiology, Department of Medicine, New York University Grossman School of Medicine, New York, New York, USA
- Department of Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Gabriela Hobbs
- Division of Hematology Oncology, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Katya Ravid
- Department of Medicine and Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, Massachusetts, USA
| | - Peter Libby
- Division of Cardiovascular Medicine, Department of Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts, USA
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20
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Bailey DM, Culcasi M, Filipponi T, Brugniaux JV, Stacey BS, Marley CJ, Soria R, Rimoldi SF, Cerny D, Rexhaj E, Pratali L, Salmòn CS, Jáuregui CM, Villena M, Villafuerte F, Rockenbauer A, Pietri S, Scherrer U, Sartori C. EPR spectroscopic evidence of iron-catalysed free radical formation in chronic mountain sickness: Dietary causes and vascular consequences. Free Radic Biol Med 2022; 184:99-113. [PMID: 35398201 DOI: 10.1016/j.freeradbiomed.2022.03.028] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Revised: 03/24/2022] [Accepted: 03/29/2022] [Indexed: 12/12/2022]
Abstract
Chronic mountain sickness (CMS) is a high-altitude (HA) maladaptation syndrome characterised by elevated systemic oxidative-nitrosative stress (OXNOS) due to a free radical-mediated reduction in vascular nitric oxide (NO) bioavailability. To better define underlying mechanisms and vascular consequences, this study compared healthy male lowlanders (80 m, n = 10) against age/sex-matched highlanders born and bred in La Paz, Bolivia (3600 m) with (CMS+, n = 10) and without (CMS-, n = 10) CMS. Cephalic venous blood was assayed using electron paramagnetic resonance spectroscopy and reductive ozone-based chemiluminescence. Nutritional intake was assessed via dietary recall. Systemic vascular function and structure were assessed via flow-mediated dilatation, aortic pulse wave velocity and carotid intima-media thickness using duplex ultrasound and applanation tonometry. Basal systemic OXNOS was permanently elevated in highlanders (P = <0.001 vs. lowlanders) and further exaggerated in CMS+, reflected by increased hydroxyl radical spin adduct formation (P = <0.001 vs. CMS-) subsequent to liberation of free 'catalytic' iron consistent with a Fenton and/or nucleophilic addition mechanism(s). This was accompanied by elevated global protein carbonylation (P = 0.046 vs. CMS-) and corresponding reduction in plasma nitrite (P = <0.001 vs. lowlanders). Dietary intake of vitamins C and E, carotene, magnesium and retinol were lower in highlanders and especially deficient in CMS + due to reduced consumption of fruit and vegetables (P = <0.001 to 0.028 vs. lowlanders/CMS-). Systemic vascular function and structure were also impaired in highlanders (P = <0.001 to 0.040 vs. lowlanders) with more marked dysfunction observed in CMS+ (P = 0.035 to 0.043 vs. CMS-) in direct proportion to systemic OXNOS (r = -0.692 to 0.595, P = <0.001 to 0.045). Collectively, these findings suggest that lifelong exposure to iron-catalysed systemic OXNOS, compounded by a dietary deficiency of antioxidant micronutrients, likely contributes to the systemic vascular complications and increased morbidity/mortality in CMS+. TRIAL REGISTRY: ClinicalTrials.gov; No: NCT01182792; URL: www.clinicaltrials.gov.
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Affiliation(s)
- Damian M Bailey
- Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, Wales, UK.
| | - Marcel Culcasi
- Aix Marseille Univ, CNRS, ICR, UMR, 7273, Marseille, France
| | - Teresa Filipponi
- Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, Wales, UK
| | - Julien V Brugniaux
- Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, Wales, UK; HP2 Laboratory, INSERM U1300, Grenoble Alpes University, Grenoble, France
| | - Benjamin S Stacey
- Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, Wales, UK
| | - Christopher J Marley
- Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, Wales, UK
| | - Rodrigo Soria
- Department of Cardiology and Biomedical Research, University Hospital, Bern, Switzerland
| | - Stefano F Rimoldi
- Department of Cardiology and Biomedical Research, University Hospital, Bern, Switzerland
| | - David Cerny
- Department of Cardiology and Biomedical Research, University Hospital, Bern, Switzerland
| | - Emrush Rexhaj
- Department of Cardiology and Biomedical Research, University Hospital, Bern, Switzerland
| | | | | | | | | | - Francisco Villafuerte
- Laboratorio de Fisiología Comparada, Departamento de Ciencias Biológicas y Fisiológicas, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Antal Rockenbauer
- Institute of Materials and Environmental Chemistry, Research Center for Natural Sciences, 1117, Budapest, Hungary
| | - Sylvia Pietri
- Aix Marseille Univ, CNRS, ICR, UMR, 7273, Marseille, France
| | - Urs Scherrer
- Department of Cardiology and Biomedical Research, University Hospital, Bern, Switzerland; Facultad de Ciencias, Departamento de Biología, Universidad de Tarapacá, Arica, Chile
| | - Claudio Sartori
- Department of Internal Medicine, University Hospital, UNIL-Lausanne, Switzerland
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21
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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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22
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Steele AR, Tymko MM, Meah VL, Simpson LL, Gasho C, Dawkins TG, Williams AM, Villafuerte FC, Vizcardo-Galindo GA, Figueroa-Mujíca RJ, Ainslie PN, Stembridge M, Moore JP, Steinback CD. Global REACH 2018: Volume regulation in high-altitude Andeans with and without chronic mountain sickness. Am J Physiol Regul Integr Comp Physiol 2021; 321:R504-R512. [PMID: 34346722 DOI: 10.1152/ajpregu.00102.2021] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The high-altitude maladaptation syndrome known as chronic mountain sickness (CMS) is characterized by polycythemia and is associated with proteinuria despite unaltered glomerular filtration rate. However, it remains unclear if indigenous highlanders with CMS have altered volume regulatory hormones. We assessed N-terminal pro-B-type natriuretic peptide (NT pro-BNP), plasma aldosterone concentration, plasma renin activity, kidney function (urinary microalbumin, glomerular filtration rate), blood volume, and estimated pulmonary artery systolic pressure (ePASP), in Andean males without (n=14; age=39±11) and with (n=10; age=40±12) CMS at 4330 meters (Cerro de Pasco, Peru). Plasma renin activity (non-CMS: 15.8±7.9 vs. CMS: 8.7±5.4 ng/ml; p=0.025) and plasma aldosterone concentration (non-CMS: 77.5±35.5 vs. CMS: 54.2±28.9 pg/ml; p=0.018) were lower in highlanders with CMS compared to non-CMS, while NT pro-BNP was not different between groups (non-CMS: 1394.9±214.3 vs. CMS: 1451.1±327.8 pg/ml; p=0.15). Highlanders had similar total blood volume (non-CMS: 90±15 vs. CMS: 103±18 ml • kg-1; p=0.071), but Andeans with CMS had greater total red blood cell volume (non-CMS: 46±10 vs. CMS 66±14 ml • kg-1; p<0.01) and smaller plasma volume (non-CMS 43±7 vs. CMS 35±5 ml • kg-1; p=0.03) compared to non-CMS. There were no differences in ePASP between groups (non-CMS 32±9 vs. CMS 31±8 mmHg; p=0.6). A negative correlation was found between plasma renin activity and glomerular filtration rate in both groups (group: r=-0.66; p<0.01; non-CMS: r=-0.60; p=0.022; CMS: r=-0.63; p=0.049). A smaller plasma volume in Andeans with CMS may indicate an additional CMS maladaptation to high-altitude, causing potentially greater polycythemia and clinical symptoms.
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Affiliation(s)
- Andrew R Steele
- Neurovascular Health Lab, Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Canada
| | - Michael M Tymko
- Neurovascular Health Lab, Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Canada
| | - Victoria L Meah
- Neurovascular Health Lab, Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Canada.,Women and Children's Health Research Institute, University of Alberta, Canada.,Alberta Diabetes Institute, University of Alberta, Canada
| | - Lydia L Simpson
- Department of Sport Science, Division of Physiology, University of Innsbruck, Austria
| | - Christopher Gasho
- Division of Pulmonary and Critical Care, School of Medicine, Loma Linda University, Loma Linda, CA, United States
| | - Tony G Dawkins
- Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, UK
| | - Alexandra Mackenzie Williams
- Department of Cellular and Physiological Sciences, Faculty of Medicine, University of British Columbia, Canada.,International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, Canada
| | - Francisco C Villafuerte
- Department of Biological and Physiological Sciences, Universidad Peruana Cayetano Heredia, Lima, Peru
| | | | - Rómulo J Figueroa-Mujíca
- Department of Biological and Physiological Sciences, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Philip N Ainslie
- Centre for Heart, Lung, and Vascular Health, University of British Columbia Okanagan, Kelowna, Canada
| | - Mike Stembridge
- Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, UK
| | - Jonathan P Moore
- Extremes Research Group, School of Sport, Health and Exercise Sciences, Bangor University, Bangor, United Kingdom
| | - Craig D Steinback
- Neurovascular Health Lab, Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Canada.,Women and Children's Health Research Institute, University of Alberta, Canada.,Alberta Diabetes Institute, University of Alberta, Canada.,Neuroscience and Mental Health Institute, University of Alberta, Canada
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23
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Zubieta-Calleja G, Zubieta-DeUrioste N. The Oxygen Transport Triad in High-Altitude Pulmonary Edema: A Perspective from the High Andes. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:7619. [PMID: 34300070 PMCID: PMC8305285 DOI: 10.3390/ijerph18147619] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 07/13/2021] [Accepted: 07/13/2021] [Indexed: 12/24/2022]
Abstract
Acute high-altitude illnesses are of great concern for physicians and people traveling to high altitude. Our recent article "Acute Mountain Sickness, High-Altitude Pulmonary Edema and High-Altitude Cerebral Edema, a View from the High Andes" was questioned by some sea-level high-altitude experts. As a result of this, we answer some observations and further explain our opinion on these diseases. High-Altitude Pulmonary Edema (HAPE) can be better understood through the Oxygen Transport Triad, which involves the pneumo-dynamic pump (ventilation), the hemo-dynamic pump (heart and circulation), and hemoglobin. The two pumps are the first physiologic response upon initial exposure to hypobaric hypoxia. Hemoglobin is the balancing energy-saving time-evolving equilibrating factor. The acid-base balance must be adequately interpreted using the high-altitude Van Slyke correction factors. Pulse-oximetry measurements during breath-holding at high altitude allow for the evaluation of high altitude diseases. The Tolerance to Hypoxia Formula shows that, paradoxically, the higher the altitude, the more tolerance to hypoxia. In order to survive, all organisms adapt physiologically and optimally to the high-altitude environment, and there cannot be any "loss of adaptation". A favorable evolution in HAPE and pulmonary hypertension can result from the oxygen treatment along with other measures.
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Affiliation(s)
- Gustavo Zubieta-Calleja
- High Altitude Pulmonary and Pathology Institute (HAPPI-IPPA), Av. Copacabana Prolongacion #55, La Paz 2826, Bolivia;
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24
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Hansen AB, Moralez G, Amin SB, Simspon LL, Hofstaetter F, Anholm JD, Gasho C, Stembridge M, Dawkins TG, Tymko MM, Ainslie PN, Villafuerte F, Romero SA, Hearon CM, Lawley JS. Global REACH 2018: the adaptive phenotype to life with chronic mountain sickness and polycythaemia. J Physiol 2021; 599:4021-4044. [PMID: 34245004 DOI: 10.1113/jp281730] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 06/18/2021] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Humans suffering from polycythaemia undergo multiple circulatory adaptations including changes in blood rheology and structural and functional vascular adaptations to maintain normal blood pressure and vascular shear stresses, despite high blood viscosity. During exercise, several circulatory adaptations are observed, especially involving adrenergic and non-adrenergic mechanisms within non-active and active skeletal muscle to maintain exercise capacity, which is not observed in animal models. Despite profound circulatory stress, i.e. polycythaemia, several adaptations can occur to maintain exercise capacity, therefore making early identification of the disease difficult without overt symptomology. Pharmacological treatment of the background heightened sympathetic activity may impair the adaptive sympathetic response needed to match local oxygen delivery to active skeletal muscle oxygen demand and therefore inadvertently impair exercise capacity. ABSTRACT Excessive haematocrit and blood viscosity can increase blood pressure, cardiac work and reduce aerobic capacity. However, past clinical investigations have demonstrated that certain human high-altitude populations suffering from excessive erythrocytosis, Andeans with chronic mountain sickness, appear to have phenotypically adapted to life with polycythaemia, as their exercise capacity is comparable to healthy Andeans and even with sea-level inhabitants residing at high altitude. By studying this unique population, which has adapted through natural selection, this study aimed to describe how humans can adapt to life with polycythaemia. Experimental studies included Andeans with (n = 19) and without (n = 17) chronic mountain sickness, documenting exercise capacity and characterizing the transport of oxygen through blood rheology, including haemoglobin mass, blood and plasma volume and blood viscosity, cardiac output, blood pressure and changes in total and local vascular resistances through pharmacological dissection of α-adrenergic signalling pathways within non-active and active skeletal muscle. At rest, Andeans with chronic mountain sickness had a substantial plasma volume contraction, which alongside a higher red blood cell volume, caused an increase in blood viscosity yet similar total blood volume. Moreover, both morphological and functional alterations in the periphery normalized vascular shear stress and blood pressure despite high sympathetic nerve activity. During exercise, blood pressure, cardiac work and global oxygen delivery increased similar to healthy Andeans but were sustained by modifications in both non-active and active skeletal muscle vascular function. These findings highlight widespread physiological adaptations that can occur in response to polycythaemia, which allow the maintenance of exercise capacity.
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Affiliation(s)
- Alexander B Hansen
- Department of Sport Science, Division of Performance Physiology and Prevention, University of Innsbruck, Innsbruck, Austria
| | - Gilbert Moralez
- Department of Applied Clinical Research, University of Southwestern Medical Center, Dallas, Texas, USA
| | - Sachin B Amin
- Department of Sport Science, Division of Performance Physiology and Prevention, University of Innsbruck, Innsbruck, Austria
| | - Lydia L Simspon
- Department of Sport Science, Division of Performance Physiology and Prevention, University of Innsbruck, Innsbruck, Austria
| | - Florian Hofstaetter
- Department of Sport Science, Division of Performance Physiology and Prevention, University of Innsbruck, Innsbruck, Austria
| | - James D Anholm
- Department of Medicine, Division of Pulmonary and Critical Care, Loma Linda University, Loma Linda, California, USA
| | - Christopher Gasho
- Department of Medicine, Division of Pulmonary and Critical Care, Loma Linda University, Loma Linda, California, USA
| | - Mike Stembridge
- Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, UK
| | - Tony G Dawkins
- Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, UK
| | - Michael M Tymko
- Physical Activity and Diabetes Laboratory, Faculty of Kinesiology, Sport and Recreation, University of Alberta, Edmonton, Alberta, Canada.,Centre of Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan, Kelowna, British Columbia, Canada
| | - Philip N Ainslie
- Centre of Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan, Kelowna, British Columbia, Canada
| | - Francisco Villafuerte
- Laboratorio de Fisiología Comparada/Fisiología del Transporte de Oxígeno, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Steven A Romero
- University of North Texas Health Science Center, Fort Worth, Texas, USA
| | - Christopher M Hearon
- Department of Applied Clinical Research, University of Southwestern Medical Center, Dallas, Texas, USA.,Institute of Exercise and Environmental Medicine, Texas Health Presbyterian Dallas, Dallas, Texas, USA
| | - Justin S Lawley
- Department of Sport Science, Division of Performance Physiology and Prevention, University of Innsbruck, Innsbruck, Austria
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25
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van Vliet T, Casciaro F, Demaria M. To breathe or not to breathe: Understanding how oxygen sensing contributes to age-related phenotypes. Ageing Res Rev 2021; 67:101267. [PMID: 33556549 DOI: 10.1016/j.arr.2021.101267] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 01/21/2021] [Accepted: 02/02/2021] [Indexed: 02/08/2023]
Abstract
Aging is characterized by a progressive loss of tissue integrity and functionality due to disrupted homeostasis. Molecular oxygen is pivotal to maintain tissue functions, and aerobic species have evolved a sophisticated sensing system to ensure proper oxygen supply and demand. It is not surprising that aberrations in oxygen and oxygen-associated pathways subvert health and promote different aspects of aging. In this review, we discuss emerging findings on how oxygen-sensing mechanisms regulate different cellular and molecular processes during normal physiology, and how dysregulation of oxygen availability lead to disease and aging. We describe various clinical manifestations associated with deregulation of oxygen balance, and how oxygen-modulating therapies and natural oxygen oscillations influence longevity. We conclude by discussing how a better understanding of oxygen-related mechanisms that orchestrate aging processes may lead to the development of new therapeutic strategies to extend healthy aging.
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26
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DeSouza NM, Brewster LM, Bain AR, Garcia VP, Stone R, Stockelman KA, Greiner JJ, Tymko MM, Vizcardo-Galindo G, Figueroa-Mujica RJ, Villafuerte FC, Ainslie PN, DeSouza CA. Global REACH 2018: Influence of excessive erythrocytosis on coagulation and fibrinolytic factors in Andean highlanders. Exp Physiol 2021; 106:1335-1342. [PMID: 33745204 DOI: 10.1113/ep089360] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Accepted: 03/17/2021] [Indexed: 11/08/2022]
Abstract
NEW FINDINGS What is the central question of this study? Are coagulation and fibrinolytic factors disrupted in Andean highlanders with excessive erythrocytosis? What is the main finding and its importance? Excessive erythrocytosis is not associated with prothombotic disruptions in coagulation or the fibrinolytic system in Andean highlanders. Impairments in coagulation and fibrinolysis may not contribute to the increased vascular risk associated with excessive erythrocytosis. ABSTRACT Increased coagulation and reduced fibrinolysis are central factors underlying thrombotic risk and events. High altitude-induced excessive erythrocytosis (EE) is prevalent in Andean highlanders, contributing to increased cardiovascular risk. Disruption in the coagulation-fibrinolytic axis resulting in uncontrolled fibrin deposition might underlie the increased thrombotic risk associated with high-altitude EE. The experimental aim of this study was to determine whether EE is associated with a prothrombotic blood coagulation and fibrinolytic profile in Andean highlanders. Plasma coagulation factors (von Willebrand factor and factors VII, VIII and X), fibrinolytic factors [tissue-type plasminogen activator (t-PA) and plasminogen activator inhibitor-1 (PAI-1)] and D-dimer levels were determined in 26 male residents of Cerro de Pasco, Peru (4340 m a.s.l.): 12 without EE (age, 40 ± 13 years; haemoglobin, 17.4 ± 1.9 g/dl) and 14 with EE (age, 43 ± 15 years; haemoglobin, 24.4 ± 1.6 g/dl). There were no significant differences in von Willebrand factor (40.5 ± 24.8 vs. 45.5 ± 22.4%), factor VII (77.0 ± 14.5 vs. 72.5 ± 8.9%), factor VIII (55.6 ± 19.8 vs. 60.7 ± 26.8%) and factor X (73.9 ± 8.3 vs. 67.3 ± 10.9%) between the Andean highlanders without or with EE. The t-PA antigen (8.5 ± 3.6 vs. 9.6 ± 5.4 ng/ml), t-PA activity (5.5 ± 2.4 vs. 5.8 ± 1.6 IU/ml), PAI antigen (45.0 ± 33.8 vs. 40.5 ± 15.8 ng/ml), PAI-1 activity (0.24 ± 0.09 vs. 0.25 ± 0.11 IU/ml) and the molar concentration ratio of active t-PA to active PAI-1 (1:0.051 ± 0.034 vs. 1:0.046 ± 0.021 mmol/l) were also similar between the groups, as were D-dimer levels (235.0 ± 126.4 vs. 268.4 ± 173.7 ng/ml). Collectively, the results of the present study indicate that EE is not associated with a hypercoagulable, hypofibrinolytic state in Andean highlanders.
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Affiliation(s)
- Noah M DeSouza
- Integrative Vascular Biology Laboratory, Department of Integrative Physiology, University of Colorado, Boulder, Colorado, USA.,Centre for Heart, Lung and Vascular Health, Faculty of Health and Social Development, University of British Columbia Okanagan, Kelowna, British Columbia, Canada
| | - L Madden Brewster
- Integrative Vascular Biology Laboratory, Department of Integrative Physiology, University of Colorado, Boulder, Colorado, USA
| | - Anthony R Bain
- Department of Kinesiology, University of Windsor, Windsor, Ontario, Canada
| | - Vinicius P Garcia
- Integrative Vascular Biology Laboratory, Department of Integrative Physiology, University of Colorado, Boulder, Colorado, USA
| | - Rachel Stone
- Department of Kinesiology, University of Windsor, Windsor, Ontario, Canada
| | - Kelly A Stockelman
- Integrative Vascular Biology Laboratory, Department of Integrative Physiology, University of Colorado, Boulder, Colorado, USA
| | - Jared J Greiner
- Integrative Vascular Biology Laboratory, Department of Integrative Physiology, University of Colorado, Boulder, Colorado, USA
| | - Michael M Tymko
- Neurovascular Health Laboratory, Faculty of Kinesiology, Sport and Recreation, University of Alberta, Edmonton, Alberta, Canada
| | - Gustavo Vizcardo-Galindo
- Laboratorio de Fisiología Comparada, Departamento de Ciencias Biológicas y Fisiológicas, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Romulo J Figueroa-Mujica
- Laboratorio de Fisiología Comparada, Departamento de Ciencias Biológicas y Fisiológicas, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Francisco C Villafuerte
- Laboratorio de Fisiología Comparada, Departamento de Ciencias Biológicas y Fisiológicas, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Philip N Ainslie
- Centre for Heart, Lung and Vascular Health, Faculty of Health and Social Development, University of British Columbia Okanagan, Kelowna, British Columbia, Canada
| | - Christopher A DeSouza
- Integrative Vascular Biology Laboratory, Department of Integrative Physiology, University of Colorado, Boulder, Colorado, USA
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27
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Brewster LM, Bain AR, Garcia VP, Fandl HK, Stone R, DeSouza NM, Greiner JJ, Tymko MM, Vizcardo-Galindo GA, Figueroa-Mujica RJ, Villafuerte FC, Ainslie PN, DeSouza CA. Global REACH 2018: dysfunctional extracellular microvesicles in Andean highlander males with excessive erythrocytosis. Am J Physiol Heart Circ Physiol 2021; 320:H1851-H1861. [PMID: 33710927 DOI: 10.1152/ajpheart.00016.2021] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
High altitude-related excessive erythrocytosis (EE) is associated with increased cardiovascular risk. The experimental aim of this study was to determine the effects of microvesicles isolated from Andean highlanders with EE on endothelial cell inflammation, oxidative stress, apoptosis, and nitric oxide (NO) production. Twenty-six male residents of Cerro de Pasco, Peru (4,340 m), were studied: 12 highlanders without EE (age: 40 ± 4 yr; BMI: 26.4 ± 1.7; Hb: 17.4 ± 0.5 g/dL, Spo2: 86.9 ± 1.0%) and 14 highlanders with EE (43 ± 4 yr; 26.2 ± 0.9; 24.4 ± 0.4 g/dL; 79.7 ± 1.6%). Microvesicles were isolated, enumerated, and collected from plasma by flow cytometry. Human umbilical vein endothelial cells were cultured and treated with microvesicles from highlanders without and with EE. Microvesicles from highlanders with EE induced significantly higher release of interleukin (IL)-6 (89.8 ± 2.7 vs. 77.1 ± 1.9 pg/mL) and IL-8 (62.0 ± 2.7 vs. 53.3 ± 2.2 pg/mL) compared with microvesicles from healthy highlanders. Although intracellular expression of total NF-κB p65 (65.3 ± 6.0 vs. 74.9 ± 7.8.9 AU) was not significantly affected in cells treated with microvesicles from highlanders without versus with EE, microvesicles from highlanders with EE resulted in an ∼25% higher (P < 0.05) expression of p-NF-κB p65 (173.6 ± 14.3 vs. 132.8 ± 12.2 AU). Cell reactive oxygen species production was significantly higher (76.4.7 ± 5.4 vs. 56.7 ± 1.7% of control) and endothelial nitric oxide synthase (p-eNOS) activation (231.3 ± 15.5 vs. 286.6 ± 23.0 AU) and NO production (8.3 ± 0.6 vs. 10.7 ± 0.7 μM/L) were significantly lower in cells treated with microvesicles from highlanders with versus without EE. Cell apoptotic susceptibility was not significantly affected by EE-related microvesicles. Circulating microvesicles from Andean highlanders with EE increased endothelial cell inflammation and oxidative stress and reduced NO production.NEW & NOTEWORTHY In this study, we determined the effects of microvesicles isolated from Andean highlanders with excessive erythrocytosis (EE) on endothelial cell inflammation, oxidative stress, apoptosis, and NO production. Microvesicles from highlanders with EE induced a dysfunctional response from endothelial cells characterized by increased cytokine release and expression of active nuclear factor-κB and reduced nitric oxide production. Andean highlanders with EE exhibit dysfunctional circulating extracellular microvesicles that induce a proinflammatory, proatherogenic endothelial phenotype.
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Affiliation(s)
- L Madden Brewster
- Integrative Vascular Biology Laboratory, Department of Integrative Physiology, University of Colorado, Boulder, Colorado
| | - Anthony R Bain
- Department of Kinesiology, University of Windsor, Windsor, Ontario, Canada
| | - Vinicius P Garcia
- Integrative Vascular Biology Laboratory, Department of Integrative Physiology, University of Colorado, Boulder, Colorado
| | - Hannah K Fandl
- Integrative Vascular Biology Laboratory, Department of Integrative Physiology, University of Colorado, Boulder, Colorado
| | - Rachel Stone
- Department of Kinesiology, University of Windsor, Windsor, Ontario, Canada
| | - Noah M DeSouza
- Integrative Vascular Biology Laboratory, Department of Integrative Physiology, University of Colorado, Boulder, Colorado.,Faculty of Health and Social Development, Centre for Heart, Lung and Vascular Health, University of British Columbia Okanagan, Kelowna, British Columbia, Canada
| | - Jared J Greiner
- Integrative Vascular Biology Laboratory, Department of Integrative Physiology, University of Colorado, Boulder, Colorado
| | | | | | | | | | - Philip N Ainslie
- Faculty of Health and Social Development, Centre for Heart, Lung and Vascular Health, University of British Columbia Okanagan, Kelowna, British Columbia, Canada
| | - Christopher A DeSouza
- Integrative Vascular Biology Laboratory, Department of Integrative Physiology, University of Colorado, Boulder, Colorado
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28
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Pooja, Sharma V, Sharma M, Varshney R, Kumar B, Sethy NK. Association Between 17β-Estradiol Receptors and Nitric Oxide Signaling Augments High-Altitude Adaptation of Ladakhi Highlanders. High Alt Med Biol 2021; 22:174-183. [PMID: 33602001 DOI: 10.1089/ham.2020.0187] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Pooja, Vandana Sharma, Manish Sharma, Rajeev Varshney, Bhuvnesh Kumar, and Niroj Kumar Sethy. Association between 17β-estradiol receptors and nitric oxide signaling augments high-altitude adaptation of Ladakhi highlanders. High Alt Med Biol. 22: 174-183, 2021. Background: Genomic studies have identified positive natural selection of plasma membrane estrogen receptor signaling pathway for Himalayan highlanders. We sought to investigate significance of this pathway for high-altitude adaptation by studying Ladakhi highlanders. Materials and Methods: We recruited 25 healthy Ladakhi males (age range: 19-37, height: 164 ± 6 cm, and weight 59 ± 4 kg) at Leh (altitude 3,520 m) and age matched sea level volunteers at Delhi (altitude 215 m), India. We evaluated circulatory levels of 17β-estradiol (E2) and testosterone (T) and levels of E2 biosynthesis pathway proteins. In addition, we analyzed mRNA levels of E2 pathway genes and their association with nitric oxide (NO) availability. Results: We observed higher circulatory E2 and lower testosterone (T) in Ladakhi highlanders compared to lowlanders. Studying E2 pathway genes, we identified higher transcript levels of E2 receptors ESR1 (2.02-fold) and ESR2 (3.87-fold) in Ladakhi highlanders. Higher NOS3 mRNA, plasma level of endothelial NO synthase (eNOS), p-eNOS Ser1177, NOx (nitrate and nitrite), and cGMP were observed for Ladakhi highlanders. In addition, we observed a positive correlation between E2 with plasma NOx (r = 0.52, p = 0.002) and cGMP (r = 0.72, p = 0.007) for Ladakhi highlanders. Conclusion: Our results demonstrate higher circulatory E2 and lower T levels in Ladakhi highlanders. Higher levels of E2 and its receptors (ESR1 and ESR2) are positively associated with observed higher levels of eNOS signaling pathway metabolites. These results highlight the functional importance of E2 and its receptors for Himalayan pattern of high-altitude adaptation.
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Affiliation(s)
- Pooja
- Peptide and Proteomics Division, Defence Institute of Physiology and Allied Sciences (DIPAS), Defence Research and Development Organization (DRDO), Delhi, India
| | - Vandana Sharma
- Peptide and Proteomics Division, Defence Institute of Physiology and Allied Sciences (DIPAS), Defence Research and Development Organization (DRDO), Delhi, India
| | - Manish Sharma
- Peptide and Proteomics Division, Defence Institute of Physiology and Allied Sciences (DIPAS), Defence Research and Development Organization (DRDO), Delhi, India
| | - Rajeev Varshney
- Peptide and Proteomics Division, Defence Institute of Physiology and Allied Sciences (DIPAS), Defence Research and Development Organization (DRDO), Delhi, India
| | - Bhuvnesh Kumar
- Peptide and Proteomics Division, Defence Institute of Physiology and Allied Sciences (DIPAS), Defence Research and Development Organization (DRDO), Delhi, India
| | - Niroj Kumar Sethy
- Peptide and Proteomics Division, Defence Institute of Physiology and Allied Sciences (DIPAS), Defence Research and Development Organization (DRDO), Delhi, India
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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: 23] [Impact Index Per Article: 7.7] [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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Aragón-Vela J, Bejder J, R Huertas J, Plaza-Diaz J, Nordsborg NB. Does intermittent exposure to high altitude increase the risk of cardiovascular disease in workers? A systematic narrative review. BMJ Open 2020; 10:e041532. [PMID: 33444211 PMCID: PMC7682469 DOI: 10.1136/bmjopen-2020-041532] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
OBJECTIVE Several working groups (eg, miners, flight crews and soldiers) are subjected to chronic intermittent hypoxic exposure. The cardiovascular implications have been studied but not systematically reviewed with focus on possible negative health implications. The aim of the present review was to systematically evaluate the hypothesis that intermittent hypoxic exposure causes cardiovascular stress detrimental to health in workers. DESIGN Systematic review. DATA SOURCES Electronic database search of PubMed, Scopus and Web of Science up to April 2020. ELIGIBILITY CRITERIA Studies of workers ≥18 years repeatedly subjected to months to years of irregular intermittent hypoxia, lasting from a few hours (eg, flight crews), one or a few days (eg, soldiers), or several days to weeks (eg, miners working at high altitude), written in English and evaluating the effect of intermittent hypoxia on cardiovascular disease were included. Animal studies, books, book chapters, personal communication and abstracts were excluded. The primary outcome measure was changes in standardised mortality ratio. DATA EXTRACTION AND SYNTHESIS Two independent reviewers extracted data and assessed risk of bias using the Cochrane Collaboration's tool. RESULTS 119 articles were identified initially, 31 of which met the inclusion criteria. Of these, 17 were retrospective cohort mortality studies (irregular short-term intermittent hypoxia), and 14 studies were observational (long-term intermittent hypoxia). The population of irregular short-term intermittent hypoxia users (flight crew) showed a lower mortality by cardiovascular disease. Long-term intermittent hypoxia over several years such as in miners or soldiers may produce increased levels of cardiac disorders (12 studies), though this is probably confounded by factors such as obesity and socioeconomic status. CONCLUSION This systematic narrative review found that cardiovascular disease mortality in flight crews is lower than average, whereas miners and soldiers exposed to intermittent hypoxia experience increased risks of cardiovascular diseases. The impact of socioeconomic status and lifestyle appears of importance. PROSPERO REGISTRY NUMBER CRD42020171301.
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Affiliation(s)
- Jerónimo Aragón-Vela
- Department of Nutrition, Exercise, and Sports (NEXS), University of Copenhagen, Copenhagen, Denmark
| | - Jacob Bejder
- Department of Nutrition, Exercise, and Sports (NEXS), University of Copenhagen, Copenhagen, Denmark
| | - Jesús R Huertas
- Department of Physiology, School of Sport Sciences, University of Granada, Granada, Spain
- Institute of Nutrition and Food Technology "José Mataix", Biomedical Research Centre, University of Granada, Granada, Spain
| | - Julio Plaza-Diaz
- Children's Hospital of Eastern Ontario Research Institute, Ottawa, Ontario, Canada
- Department of Biochemistry & MolecularBiology II, School of Pharmacy, University of Granada, Granada, Spain
- Instituto de Investigación Biosanitaria IBS Granada, Complejo Hospitalario Universitario de Granada, Granada, Spain
| | - Nikolai B Nordsborg
- Department of Nutrition, Exercise, and Sports (NEXS), University of Copenhagen, Copenhagen, Denmark
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Bilo G, Acone L, Anza-Ramírez C, Macarlupú JL, Soranna D, Zambon A, Vizcardo-Galindo G, Pengo MF, Villafuerte FC, Parati G. Office and Ambulatory Arterial Hypertension in Highlanders: HIGHCARE-ANDES Highlanders Study. Hypertension 2020; 76:1962-1970. [PMID: 33175629 DOI: 10.1161/hypertensionaha.120.16010] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Millions of people worldwide live at high altitude, being chronically exposed to hypobaric hypoxia. Hypertension is a major cardiovascular risk factor but data on its prevalence and determinants in highlanders are limited, and systematic studies with ambulatory blood pressure monitoring are not available. Aim of this study was to assess the prevalence of clinic and ambulatory hypertension and the associated factors in a sample of Andean highlanders. Hypertension prevalence and phenotypes were assessed with office and ambulatory blood pressure measurement in a sample of adults living in Cerro de Pasco, Peru (altitude 4340 m). Basic clinical data, blood oxygen saturation, hematocrit, and Qinghai Chronic Mountain Sickness score were obtained. Participants were classified according to the presence of excessive erythrocytosis and chronic mountain sickness diagnosis. Data of 289 participants (143 women, 146 men, mean age 38.3 years) were analyzed. Office hypertension was present in 20 (7%) participants, while ambulatory hypertension was found in 58 (20%) participants. Masked hypertension was common (15%), and white coat hypertension was rare (2%). Among participants with ambulatory hypertension, the most prevalent phenotypes included isolated nocturnal hypertension, isolated diastolic hypertension, and systodiastolic hypertension. Ambulatory hypertension was associated with male gender, age, overweight/obesity, 24-hour heart rate, and excessive erythrocytosis. Prevalence of hypertension among Andean highlanders may be significantly underestimated when based on conventional blood pressure measurements, due to the high prevalence of masked hypertension. In highlanders, ambulatory hypertension may be independently associated with excessive erythrocytosis.
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Affiliation(s)
- Grzegorz Bilo
- From the Department of Cardiovascular, Neural and Metabolic Sciences (G.B., M.F.P., G.P.), University of Milano-Bicocca, Milan, Italy.,Istituto Auxologico Italiano, IRCCS, Milan, Italy Department of Medicine and Surgery (G.B., L.A., G.P.), University of Milano-Bicocca, Milan, Italy
| | - Lorenzo Acone
- Istituto Auxologico Italiano, IRCCS, Milan, Italy Department of Medicine and Surgery (G.B., L.A., G.P.), University of Milano-Bicocca, Milan, Italy
| | - Cecilia Anza-Ramírez
- Laboratorio de Fisiología Comparada/Fisiología del Transporte de Oxígeno-LID. Universidad Peruana Cayetano Heredia, Lima, Perú (C.A.-R., J.L.M., G.V.-G., F.C.V.)
| | - José Luis Macarlupú
- Laboratorio de Fisiología Comparada/Fisiología del Transporte de Oxígeno-LID. Universidad Peruana Cayetano Heredia, Lima, Perú (C.A.-R., J.L.M., G.V.-G., F.C.V.)
| | - Davide Soranna
- Biostatistics Unit (D.S., A.Z.), University of Milano-Bicocca, Milan, Italy
| | - Antonella Zambon
- Biostatistics Unit (D.S., A.Z.), University of Milano-Bicocca, Milan, Italy.,Department of Statistics and Quantitative Methods (A.Z.), University of Milano-Bicocca, Milan, Italy
| | - Gustavo Vizcardo-Galindo
- Laboratorio de Fisiología Comparada/Fisiología del Transporte de Oxígeno-LID. Universidad Peruana Cayetano Heredia, Lima, Perú (C.A.-R., J.L.M., G.V.-G., F.C.V.)
| | - Martino F Pengo
- From the Department of Cardiovascular, Neural and Metabolic Sciences (G.B., M.F.P., G.P.), University of Milano-Bicocca, Milan, Italy
| | - Francisco C Villafuerte
- Laboratorio de Fisiología Comparada/Fisiología del Transporte de Oxígeno-LID. Universidad Peruana Cayetano Heredia, Lima, Perú (C.A.-R., J.L.M., G.V.-G., F.C.V.)
| | - Gianfranco Parati
- From the Department of Cardiovascular, Neural and Metabolic Sciences (G.B., M.F.P., G.P.), University of Milano-Bicocca, Milan, Italy.,Istituto Auxologico Italiano, IRCCS, Milan, Italy Department of Medicine and Surgery (G.B., L.A., G.P.), University of Milano-Bicocca, Milan, Italy
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Pamenter ME, Hall JE, Tanabe Y, Simonson TS. Cross-Species Insights Into Genomic Adaptations to Hypoxia. Front Genet 2020; 11:743. [PMID: 32849780 PMCID: PMC7387696 DOI: 10.3389/fgene.2020.00743] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2020] [Accepted: 06/22/2020] [Indexed: 12/13/2022] Open
Abstract
Over millions of years, vertebrate species populated vast environments spanning the globe. Among the most challenging habitats encountered were those with limited availability of oxygen, yet many animal and human populations inhabit and perform life cycle functions and/or daily activities in varying degrees of hypoxia today. Of particular interest are species that inhabit high-altitude niches, which experience chronic hypobaric hypoxia throughout their lives. Physiological and molecular aspects of adaptation to hypoxia have long been the focus of high-altitude populations and, within the past decade, genomic information has become increasingly accessible. These data provide an opportunity to search for common genetic signatures of selection across uniquely informative populations and thereby augment our understanding of the mechanisms underlying adaptations to hypoxia. In this review, we synthesize the available genomic findings across hypoxia-tolerant species to provide a comprehensive view of putatively hypoxia-adaptive genes and pathways. In many cases, adaptive signatures across species converge on the same genetic pathways or on genes themselves [i.e., the hypoxia inducible factor (HIF) pathway). However, specific variants thought to underlie function are distinct between species and populations, and, in most cases, the precise functional role of these genomic differences remains unknown. Efforts to standardize these findings and explore relationships between genotype and phenotype will provide important clues into the evolutionary and mechanistic bases of physiological adaptations to environmental hypoxia.
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Affiliation(s)
- Matthew E. Pamenter
- Department of Biology, University of Ottawa, Ottawa, ON, Canada
- Ottawa Brain and Mind Research Institute, University of Ottawa, Ottawa, ON, Canada
| | - James E. Hall
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, School of Medicine, University of California, San Diego, San Diego, CA, United States
| | - Yuuka Tanabe
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, School of Medicine, University of California, San Diego, San Diego, CA, United States
| | - Tatum S. Simonson
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, School of Medicine, University of California, San Diego, San Diego, CA, United States
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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: 23] [Impact Index Per Article: 5.8] [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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Sulaiman X, Xu WF, Cai LH, Huang XY, Cheng LF, Zhang YP. Hematologic and spirometric characteristics of Tajik and Kyrgyz highlanders in the Pamir Mountains. Am J Hum Biol 2020; 33:e23459. [PMID: 32643228 DOI: 10.1002/ajhb.23459] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 06/01/2020] [Accepted: 06/02/2020] [Indexed: 12/19/2022] Open
Abstract
OBJECTIVES In this study, we measured the hematologic and spirometric parameters of native Tajik and Kyrgyz highlanders in the Pamir Mountains to investigate adaptations to high altitude stressors. METHODS Hematological parameters including arterial oxygen saturation (SaO2 ), red blood cell (RBC) counts, and hemoglobin (Hb) concentration were measured on Sarikoli Tajik (n = 80; 3100 m), Wakhi Tajik (n = 48; 3500 m), and Kyrgyz (n = 64; 3250 m) in comparison to lowland Uyghurs (n = 50; 1300 m). Spirometric parameters including forced vital capacity (FVC), the first second of forced expiration (FEV1), and forced expiratory flow between 25% and 75% (FEF25-75) were measured. We also reported mountain sickness symptoms in these highlanders and conducted a multivariate regression analysis to analyze the association between these symptoms and the measured parameters. RESULTS SaO2 of Sarikoli Tajik, Wakhi Tajik, and Kyrgyz (91%-93.5%) are significantly lower than lowland Uyghurs, yet are comparable to other native highlanders at a similar altitude. RBC counts and Hb concentrations of all three highland populations are significantly increased compared to Uyghurs. FVC is lower in Sarikoli Tajik, Wakhi Tajik, and Kyrgyz (male: 3.48-3.86 L, female: 2.47-2.78 L) compared to Uyghurs. Combined with normal FEV1, elevated FEV1/FVC ratio, and FEF25-75, the spirometric patterns of these highlanders indicate restrictive lung disease. A high prevalence of mountain sickness symptoms such as headache and nausea was found in all three highland populations, and are attributed to low FVC and aging by regression analysis. CONCLUSION Tajik and Kyrgyz highlanders showed adaptation in SaO2 , RBC, and Hb level, but poor performance in spirometry, which causes mountain sickness.
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Affiliation(s)
- Xierzhatijiang Sulaiman
- Department of Pharmacology, School of Pharmacy, Xinjiang Medical University, Urumqi, Xinjiang, China
| | - Wei-Fang Xu
- Shenzhen Hospital of Guangzhou University of Chinese Medicine, Shenzhen, Guangdong, China
| | | | - Xiao-Yang Huang
- The People's Hospital of Shawan County, Shawan, Xinjiang, China
| | - Lu-Feng Cheng
- Department of Pharmacology, School of Pharmacy, Xinjiang Medical University, Urumqi, Xinjiang, China
| | - Ya-Ping Zhang
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, China.,State Key Laboratory for Conservation and Utilization of Bio-Resources, Yunnan University, Kunming, Yunnan, China.,Kunming College of Life Science, University of Chinese Academy of Sciences, Kunming, Yunnan, China.,KIZ-CUHK Joint Laboratory of Bioresources and Molecular Research in Common Diseases, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan, China.,Center for Excellence in Animal Evolution and Genetics, Chinese Academy of Sciences, Kunming, Yunnan, China
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Simpson LL, Meah VL, Steele AR, Gasho C, Howe CA, Dawkins TG, Busch SA, Oliver SJ, Moralez G, Lawley JS, Tymko MM, Vizcardo-Galindo GA, Figueroa-Mujíca RJ, Villafuerte FC, Ainslie PN, Stembridge M, Steinback CD, Moore JP. Global REACH 2018: Andean highlanders, chronic mountain sickness and the integrative regulation of resting blood pressure. Exp Physiol 2020; 106:104-116. [PMID: 32271969 DOI: 10.1113/ep088473] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Accepted: 04/06/2020] [Indexed: 12/17/2022]
Abstract
NEW FINDINGS What is the central question of this study? Does chronic mountain sickness (CMS) alter sympathetic neural control and arterial baroreflex regulation of blood pressure in Andean (Quechua) highlanders? What is the main finding and its importance? Compared to healthy Andean highlanders, basal sympathetic vasomotor outflow is lower, baroreflex control of muscle sympathetic nerve activity is similar, supine heart rate is lower and cardiovagal baroreflex gain is greater in mild CMS. Taken together, these findings reflect flexibility in integrative regulation of blood pressure that may be important when blood viscosity and blood volume are elevated in CMS. ABSTRACT The high-altitude maladaptation syndrome chronic mountain sickness (CMS) is characterized by excessive erythrocytosis and frequently accompanied by accentuated arterial hypoxaemia. Whether altered autonomic cardiovascular regulation is apparent in CMS is unclear. Therefore, during the 2018 Global REACH expedition to Cerro de Pasco, Peru (4383 m), we assessed integrative control of blood pressure (BP) and determined basal sympathetic vasomotor outflow and arterial baroreflex function in eight Andean natives with CMS ([Hb] 22.6 ± 0.9 g·dL-1 ) and seven healthy highlanders ([Hb] 19.3 ± 0.8 g·dL-1 ). R-R interval (RRI, electrocardiogram), beat-by-beat BP (photoplethysmography) and muscle sympathetic nerve activity (MSNA; microneurography) were recorded at rest and during pharmacologically induced changes in BP (modified Oxford test). Although [Hb] and blood viscosity (7.8 ± 0.7 vs. 6.6 ± 0.7 cP; d = 1.7, P = 0.01) were elevated in CMS compared to healthy highlanders, cardiac output, total peripheral resistance and mean BP were similar between groups. The vascular sympathetic baroreflex MSNA set-point (i.e. MSNA burst incidence) and reflex gain (i.e. responsiveness) were also similar between groups (MSNA set-point, d = 0.75, P = 0.16; gain, d = 0.2, P = 0.69). In contrast, in CMS the cardiovagal baroreflex operated around a longer RRI (960 ± 159 vs. 817 ± 50 ms; d = 1.4, P = 0.04) with a greater reflex gain (17.2 ± 6.8 vs. 8.8 ± 2.6 ms·mmHg-1 ; d = 1.8, P = 0.01) versus healthy highlanders. Basal sympathetic vasomotor activity was also lower compared to healthy highlanders (33 ± 11 vs. 45 ± 13 bursts·min-1 ; d = 1.0, P = 0.08). In conclusion, our findings indicate adaptive differences in basal sympathetic vasomotor activity and heart rate compensate for the haemodynamic consequences of excessive erythrocyte volume and contribute to integrative blood pressure regulation in Andean highlanders with mild CMS.
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Affiliation(s)
- Lydia L Simpson
- Extremes Research Group, School of Sport, Health and Exercise Sciences, Bangor University, Bangor, UK
| | - Victoria L Meah
- Neurovascular Health Laboratory, Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Edmonton, Canada
| | - Andrew R Steele
- Neurovascular Health Laboratory, Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Edmonton, Canada
| | - Christopher Gasho
- Division of Pulmonary and Critical Care, School of Medicine, Loma Linda University, Loma Linda, CA, USA
| | - Connor A Howe
- Centre for Heart, Lung, and Vascular Health, University of British Columbia Okanagan, Kelowna, Canada
| | - Tony G Dawkins
- Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, UK
| | - Stephen A Busch
- Neurovascular Health Laboratory, Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Edmonton, Canada
| | - Samuel J Oliver
- Extremes Research Group, School of Sport, Health and Exercise Sciences, Bangor University, Bangor, UK
| | - Gilberto Moralez
- Department of Applied Clinical Research, University of Texas Southwestern Medical Centre, Dallas, TX, USA
| | - Justin S Lawley
- Department of Sport Science, Division of Physiology, University of Innsbruck, Innsbruck, Austria
| | - Michael M Tymko
- Neurovascular Health Laboratory, Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Edmonton, Canada
| | | | - Rómulo J Figueroa-Mujíca
- Department of Biological and Physiological Sciences, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Francisco C Villafuerte
- Department of Biological and Physiological Sciences, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Phillip N Ainslie
- Centre for Heart, Lung, and Vascular Health, University of British Columbia Okanagan, Kelowna, Canada
| | - Mike Stembridge
- Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, UK
| | - Craig D Steinback
- Neurovascular Health Laboratory, Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Edmonton, Canada
| | - Jonathan P Moore
- Extremes Research Group, School of Sport, Health and Exercise Sciences, Bangor University, Bangor, UK
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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: 11] [Impact Index Per Article: 2.8] [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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Tymko MM, Lawley JS, Ainslie PN, Hansen AB, Hofstaetter F, Rainer S, Amin S, Moralez G, Gasho C, Vizcardo-Galindo G, Bermudez D, Villafuerte FC, Hearon CM. Global Reach 2018 Heightened α-Adrenergic Signaling Impairs Endothelial Function During Chronic Exposure to Hypobaric Hypoxia. Circ Res 2020; 127:e1-e13. [PMID: 32268833 DOI: 10.1161/circresaha.119.316053] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
RATIONALE Chronic exposure to hypoxia is associated with elevated sympathetic nervous activity and reduced vascular function in lowlanders, and Andean highlanders suffering from excessive erythrocytosis (EE); however, the mechanistic link between chronically elevated sympathetic nervous activity and hypoxia-induced vascular dysfunction has not been determined. OBJECTIVE To determine the impact of heightened sympathetic nervous activity on resistance artery endothelial-dependent dilation (EDD), and endothelial-independent dilation, in lowlanders and Andean highlanders with and without EE. METHODS AND RESULTS We tested healthy lowlanders (n=9) at sea level (344 m) and following 14 to 21 days at high altitude (4300 m), and permanent Andean highlanders with (n=6) and without (n=9) EE at high altitude. Vascular function was assessed using intraarterial infusions (3 progressive doses) of acetylcholine (ACh; EDD) and sodium nitroprusside (endothelial-independent dilation) before and after local α+β adrenergic receptor blockade (phentolamine and propranolol). Intraarterial blood pressure, heart rate, and simultaneous brachial artery diameter and blood velocity were recorded at rest and during drug infusion. Changes in forearm vascular conductance were calculated. The main findings were (1) chronic hypoxia reduced EDD in lowlanders (changes in forearm vascular conductance from sea level: ACh1: -52.7±19.6%, ACh2: -25.4±38.7%, ACh3: -35.1±34.7%, all P≤0.02); and in Andeans with EE compared with non-EE (changes in forearm vascular conductance at ACh3: -36.4%, P=0.007). Adrenergic blockade fully restored EDD in lowlanders at high altitude, and normalized EDD between EE and non-EE Andeans. (2) Chronic hypoxia had no effect on endothelial-independent dilation in lowlanders, and no differences were detected between EE and non-EE Andeans; however, EID was increased in the non-EE Andeans after adrenergic blockade (P=0.012), but this effect was not observed in the EE Andeans. CONCLUSIONS These data indicate that chronic hypoxia reduces EDD via heightened α-adrenergic signaling in lowlanders and in Andeans with EE. These vascular mechanisms have important implications for understanding the physiological consequences of acute and chronic high altitude adaptation.
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Affiliation(s)
- Michael M Tymko
- From the Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Science, University of British Columbia, Kelowna, Canada (M.M.T., P.N.A.).,Neurovascular Health Lab, Faculty of Kinesiology, Sport and Recreation, University of Alberta, Edmonton, Canada (M.M.T.)
| | - Justin S Lawley
- University of Innsbruck, Austria (J.S.L., A.B.H., F.H., S.R., S.A.)
| | - Philip N Ainslie
- From the Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Science, University of British Columbia, Kelowna, Canada (M.M.T., P.N.A.)
| | | | | | - Simon Rainer
- University of Innsbruck, Austria (J.S.L., A.B.H., F.H., S.R., S.A.)
| | - Sachin Amin
- University of Innsbruck, Austria (J.S.L., A.B.H., F.H., S.R., S.A.)
| | - Gilbert Moralez
- Department of Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, TX (G.M.)
| | | | | | | | | | - Christopher M Hearon
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital of Dallas (C.M.H.).,Department of Internal Medicine, University of Texas Southwestern Medical Center (C.M.H.)
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Iron and Sphingolipids as Common Players of (Mal)Adaptation to Hypoxia in Pulmonary Diseases. Int J Mol Sci 2020; 21:ijms21010307. [PMID: 31906427 PMCID: PMC6981703 DOI: 10.3390/ijms21010307] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Revised: 12/24/2019] [Accepted: 12/31/2019] [Indexed: 12/11/2022] Open
Abstract
Hypoxia, or lack of oxygen, can occur in both physiological (high altitude) and pathological conditions (respiratory diseases). In this narrative review, we introduce high altitude pulmonary edema (HAPE), acute respiratory distress syndrome (ARDS), Chronic Obstructive Pulmonary Disease (COPD), and Cystic Fibrosis (CF) as examples of maladaptation to hypoxia, and highlight some of the potential mechanisms influencing the prognosis of the affected patients. Among the specific pathways modulated in response to hypoxia, iron metabolism has been widely explored in recent years. Recent evidence emphasizes hepcidin as highly involved in the compensatory response to hypoxia in healthy subjects. A less investigated field in the adaptation to hypoxia is the sphingolipid (SPL) metabolism, especially through Ceramide and sphingosine 1 phosphate. Both individually and in concert, iron and SPL are active players of the (mal)adaptation to physiological hypoxia, which can result in the pathological HAPE. Our aim is to identify some pathways and/or markers involved in the physiological adaptation to low atmospheric pressures (high altitudes) that could be involved in pathological adaptation to hypoxia as it occurs in pulmonary inflammatory diseases. Hepcidin, Cer, S1P, and their interplay in hypoxia are raising growing interest both as prognostic factors and therapeutical targets.
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Tymko MM, Tremblay JC, Bailey DM, Green DJ, Ainslie PN. The impact of hypoxaemia on vascular function in lowlanders and high altitude indigenous populations. J Physiol 2019; 597:5759-5776. [PMID: 31677355 DOI: 10.1113/jp277191] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Accepted: 10/07/2019] [Indexed: 12/18/2022] Open
Abstract
Exposure to hypoxia elicits widespread physiological responses that are critical for successful acclimatization; however, these responses may induce apparent maladaptive consequences. For example, recent studies conducted in both the laboratory and the field (e.g. at high altitude) have demonstrated that endothelial function is reduced in hypoxia. Herein, we review the several proposed mechanism(s) pertaining to the observed reduction in endothelial function in hypoxia including: (i) changes in blood flow patterns (i.e. shear stress), (ii) increased inflammation and production of reactive oxygen species (i.e. oxidative stress), (iii) heightened sympathetic nerve activity, and (iv) increased red blood cell concentration and mass leading to elevated nitric oxide scavenging. Although some of these mechanism(s) have been examined in lowlanders, less in known about endothelial function in indigenous populations that have chronically adapted to environmental hypoxia for millennia (e.g. the Peruvian, Tibetan and Ethiopian highlanders). There is some evidence indicating that healthy Tibetan and Peruvian (i.e. Andean) highlanders have preserved endothelial function at high altitude, but less is known about the Ethiopian highlanders. However, Andean highlanders suffering from chronic mountain sickness, which is characterized by an excessive production of red blood cells, have markedly reduced endothelial function. This review will provide a framework and mechanistic model for vascular endothelial adaptation to hypoxia in lowlanders and highlanders. Elucidating the pathways responsible for vascular adaption/maladaptation to hypoxia has potential clinical implications for disease featuring low oxygen delivery (e.g. heart failure, pulmonary disease). In addition, a greater understanding of vascular function at high altitude will clinically benefit the global estimated 85 million high altitude residents.
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Affiliation(s)
- Michael M Tymko
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan, Kelowna, British Columbia, Canada.,Faculty of Physical Education and Recreation, University of Alberta, Edmonton, Alberta, Canada
| | - Joshua C Tremblay
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan, Kelowna, British Columbia, Canada
| | - Damian M Bailey
- Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, UK
| | - Daniel J Green
- Cardiovascular Research Group, School of Human Sciences (Exercise and Sport Science), University of Western Australia, Perth, Australia.,Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK
| | - Philip N Ainslie
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan, Kelowna, British Columbia, Canada
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40
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Tremblay JC, Hoiland RL, Howe CA, Coombs GB, Vizcardo-Galindo GA, Figueroa-Mujíca RJ, Bermudez D, Gibbons TD, Stacey BS, Bailey DM, Tymko MM, MacLeod DB, Gasho C, Villafuerte FC, Pyke KE, Ainslie PN. Global REACH 2018: High Blood Viscosity and Hemoglobin Concentration Contribute to Reduced Flow-Mediated Dilation in High-Altitude Excessive Erythrocytosis. Hypertension 2019; 73:1327-1335. [PMID: 31006327 DOI: 10.1161/hypertensionaha.119.12780] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Excessive erythrocytosis (EE; hemoglobin concentration [Hb] ≥21 g/dL in adult males) is associated with increased cardiovascular risk in highlander Andeans. We sought to quantify shear stress and assess endothelial function via flow-mediated dilation (FMD) in male Andeans with and without EE. We hypothesized that FMD would be impaired in Andeans with EE after accounting for shear stress and that FMD would improve after isovolemic hemodilution. Brachial artery shear stress and FMD were assessed in 23 male Andeans without EE (age: 40±15 years [mean±SD]; Hb<21 g/dL) and 19 male Andeans with EE (age: 43±14 years; Hb≥21 g/dL) in Cerro de Pasco, Peru (4330 m). Shear stress was quantified from Duplex ultrasound measures of shear rate and blood viscosity. In a subset of participants (n=8), FMD was performed before and after isovolemic hemodilution with blood volume replaced by an equal volume of human serum albumin. Blood viscosity and Hb were 48% and 23% higher (both P<0.001) and FMD was 28% lower after adjusting for the shear stress stimulus ( P=0.013) in Andeans with EE compared to those without. FMD was inversely correlated with blood viscosity ( r2=0.303; P<0.001) and Hb ( r2=0.230; P=0.001). Isovolemic hemodilution decreased blood viscosity by 30±10% and Hb by 14±5% (both P<0.001) and improved shear stress stimulus-adjusted FMD from 2.7±1.9% to 4.3±1.9% ( P=0.022). Hyperviscosity, high Hb, or both, actively contribute to acutely reversible impairments in FMD in EE, suggesting that this plays a pathogenic role in the increased cardiovascular risk.
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Affiliation(s)
- Joshua C Tremblay
- From the Cardiovascular Stress Response Laboratory, School of Kinesiology and Health Studies, Queen's University, Kingston, ON, Canada (J.C.T., K.E.P.)
| | - Ryan L Hoiland
- Centre for Heart, Lung & Vascular Health, Faculty of Health and Social Development, University of British Columbia-Okanagan, Kelowna, Canada (R.L.H., C.A.H., G.B.C., M.M.T., P.N.A.)
| | - Connor A Howe
- Centre for Heart, Lung & Vascular Health, Faculty of Health and Social Development, University of British Columbia-Okanagan, Kelowna, Canada (R.L.H., C.A.H., G.B.C., M.M.T., P.N.A.)
| | - Geoff B Coombs
- Centre for Heart, Lung & Vascular Health, Faculty of Health and Social Development, University of British Columbia-Okanagan, Kelowna, Canada (R.L.H., C.A.H., G.B.C., M.M.T., P.N.A.)
| | - Gustavo A Vizcardo-Galindo
- Laboratorio de Fisiología Comparada, Departamento de Ciencias Biológicas y Fisiológicas, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Perú (G.A.V.-G., R.J.F.-M., D.B., F.C.V.)
| | - Rómulo J Figueroa-Mujíca
- Laboratorio de Fisiología Comparada, Departamento de Ciencias Biológicas y Fisiológicas, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Perú (G.A.V.-G., R.J.F.-M., D.B., F.C.V.)
| | - Daniela Bermudez
- Laboratorio de Fisiología Comparada, Departamento de Ciencias Biológicas y Fisiológicas, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Perú (G.A.V.-G., R.J.F.-M., D.B., F.C.V.)
| | - Travis D Gibbons
- School of Physical Education, Sport and Exercise Sciences, Division of Sciences, University of Otago, Dunedin, New Zealand (T.D.G.)
| | - Benjamin S Stacey
- Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, United Kingdom (B.S.S., D.M.B.)
| | - Damian M Bailey
- Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, United Kingdom (B.S.S., D.M.B.)
| | - Michael M Tymko
- Centre for Heart, Lung & Vascular Health, Faculty of Health and Social Development, University of British Columbia-Okanagan, Kelowna, Canada (R.L.H., C.A.H., G.B.C., M.M.T., P.N.A.)
| | - David B MacLeod
- Human Pharmacology and Physiology Laboratory, Department of Anesthesiology, Duke University Medical Center, Durham, NC (D.B.M.)
| | - Chris Gasho
- Division of Pulmonary, Critical Care, Hyperbaric and Sleep Medicine, Loma Linda University School of Medicine, CA (C.G.)
| | - Francisco C Villafuerte
- Laboratorio de Fisiología Comparada, Departamento de Ciencias Biológicas y Fisiológicas, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Perú (G.A.V.-G., R.J.F.-M., D.B., F.C.V.)
| | - Kyra E Pyke
- From the Cardiovascular Stress Response Laboratory, School of Kinesiology and Health Studies, Queen's University, Kingston, ON, Canada (J.C.T., K.E.P.)
| | - Philip N Ainslie
- Centre for Heart, Lung & Vascular Health, Faculty of Health and Social Development, University of British Columbia-Okanagan, Kelowna, Canada (R.L.H., C.A.H., G.B.C., M.M.T., P.N.A.)
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Tremblay JC, Coombs GB, Howe CA, Vizcardo-Galindo GA, Figueroa-Mujíca RJ, Bermudez D, Tymko MM, Villafuerte FC, Ainslie PN, Pyke KE. Global Reach 2018: reduced flow-mediated dilation stimulated by sustained increases in shear stress in high-altitude excessive erythrocytosis. Am J Physiol Heart Circ Physiol 2019; 317:H991-H1001. [PMID: 31441692 DOI: 10.1152/ajpheart.00316.2019] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Excessive erythrocytosis [EE; hemoglobin concentration (Hb) ≥ 21 g/dL in adult men] is a maladaptive high-altitude pathology associated with increased cardiovascular risk and reduced reactive hyperemia flow-mediated dilation (FMD); however, whether a similar impairment occurs in response to more commonly encountered sustained increases in shear stress [sustained stimulus (SS)-FMD] over a range of overlapping stimuli is unknown. We characterized SS-FMD in response to handgrip exercise in Andeans with and without EE in Cerro de Pasco, Peru (4,330 m). Andean highlanders with EE (n = 17, Hb = 23.2 ± 1.2 g/dL) and without EE (n = 23, Hb = 18.7 ± 1.9 g/dL) performed 3 min of rhythmic handgrip exercise at 20, 35, and 50% of maximum voluntary contraction (MVC). Duplex ultrasound was used to continuously record blood velocity and diameter in the brachial artery, and blood viscosity was measured to accurately calculate shear stress. Although baseline shear stress did not differ, Andeans with EE had 22% lower shear stress than Andeans without at 50% MVC (P = 0.004). At 35 and 50% MVC, SS-FMD was 2.1 ± 2.0 and 2.8 ± 2.7% in Andeans with EE compared with 4.1 ± 3.4 and 7.5 ± 4.5% in those without (P = 0.048 and P < 0.001). The stimulus-response slope (∆shear stress vs. ∆diameter) was lower in Andeans with EE compared with Andeans without (P = 0.028). This slope was inversely related to Hb in Andeans with EE (r2 = 0.396, P = 0.007). A reduced SS-FMD in response to small muscle mass exercise in Andeans with EE indicates a generalized reduction in endothelial sensitivity to shear stress, which may contribute to increased cardiovascular risk in this population.NEW & NOTEWORTHY High-altitude excessive erythrocytosis (EE; hemoglobin concentration ≥ 21 g/dL) is a maladaptation to chronic hypoxia exposure and is associated with increased cardiovascular risk. We examined flow-mediated dilation (FMD) in response to sustained elevations in shear stress achieved using progressive handgrip exercise [sustained stimulus (SS)-FMD] in Andean highlanders with and without EE at 4,330 m. Andeans with EE demonstrated lower SS-FMD compared with those without. Heightened hemoglobin concentration was related to lower SS-FMD in Andeans with EE.
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Affiliation(s)
- Joshua C Tremblay
- Cardiovascular Stress Response Laboratory, School of Kinesiology and Health Studies, Queen's University, Kingston, Ontario, Canada
| | - Geoff B Coombs
- Centre for Heart, Lung and Vascular Health, Faculty of Health and Social Development, University of British Columbia Okanagan, Kelowna, British Columbia, Canada
| | - Connor A Howe
- Centre for Heart, Lung and Vascular Health, Faculty of Health and Social Development, University of British Columbia Okanagan, Kelowna, British Columbia, Canada
| | - Gustavo A Vizcardo-Galindo
- Laboratorio de Fisiología Comparada, Departamento de Ciencias Biológicas y Fisiológicas, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Perú
| | - Rómulo J Figueroa-Mujíca
- Laboratorio de Fisiología Comparada, Departamento de Ciencias Biológicas y Fisiológicas, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Perú
| | - Daniela Bermudez
- Laboratorio de Fisiología Comparada, Departamento de Ciencias Biológicas y Fisiológicas, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Perú
| | - Michael M Tymko
- Centre for Heart, Lung and Vascular Health, Faculty of Health and Social Development, University of British Columbia Okanagan, Kelowna, British Columbia, Canada
| | - Francisco C Villafuerte
- Laboratorio de Fisiología Comparada, Departamento de Ciencias Biológicas y Fisiológicas, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Perú
| | - Philip N Ainslie
- Centre for Heart, Lung and Vascular Health, Faculty of Health and Social Development, University of British Columbia Okanagan, Kelowna, British Columbia, Canada
| | - Kyra E Pyke
- Cardiovascular Stress Response Laboratory, School of Kinesiology and Health Studies, Queen's University, Kingston, Ontario, Canada
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Akunov A, Sydykov A, Toktash T, Doolotova A, Sarybaev A. Hemoglobin Changes After Long-Term Intermittent Work at High Altitude. Front Physiol 2018; 9:1552. [PMID: 30443224 PMCID: PMC6221958 DOI: 10.3389/fphys.2018.01552] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2018] [Accepted: 10/16/2018] [Indexed: 12/11/2022] Open
Abstract
Chronic high altitude hypoxia leads to an increase in red cell numbers and hemoglobin concentration. However, the effects of long-term intermittent hypoxia on hemoglobin concentration have not fully been studied. The aim of this study was to evaluate hemoglobin levels in workers commuting between an elevation of 3,800 m (2-week working shift) and lowland below 1,700 m (2 weeks of holiday). A total of 266 healthy males, aged from 20 to 69 years (mean age 45.9 ± 0.6 years), were included into this study. The duration of intermittent high altitude exposure ranged from 0 to 21 years. Any cardiac or pulmonary disorder was excluded during annual check-ups including clinical examination, clinical lab work (blood cell count, urine analysis, and biochemistry), ECG, echocardiography, and pulmonary function tests. The mean hemoglobin level in workers was 16.2 ± 0.11 g/dL. Univariate linear regression revealed an association of the hemoglobin levels with the years of exposure. Hemoglobin levels increased 0.068 g/dL [95% CI: 0.037 to 0.099, p < 0.001] for every year of intermittent high altitude exposure. Further, after adjusting for other confounding variables (age, living at low or moderate altitude, body mass index, and occupation) using multivariable regression analysis, the magnitude of hemoglobin level changes decreased, but remained statistically significant: 0.046 g/dL [95% CI: 0.005 to 0.086, p < 0.05]. Besides that, a weak linear relationship between hemoglobin levels and body mass index was revealed, which was independent of the years of exposure to high altitude (0.065 g/dL [95% CI: 0.006 to 0.124, p < 0.05]). We concluded that hemoglobin levels have a linear relationship with the exposure years spent in intermittent hypoxia and body mass index.
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Affiliation(s)
- Almaz Akunov
- Department of Mountain and Sleep Medicine and Pulmonary Hypertension, National Center of Cardiology and Internal Medicine, Bishkek, Kyrgyzstan.,Kyrgyz Indian Mountain Biomedical Research Center, Bishkek, Kyrgyzstan
| | - Akylbek Sydykov
- Department of Mountain and Sleep Medicine and Pulmonary Hypertension, National Center of Cardiology and Internal Medicine, Bishkek, Kyrgyzstan.,Excellence Cluster Cardio-Pulmonary System, Universities of Giessen and Marburg Lung Center, Member of the German Center for Lung Research (DZL), Justus Liebig University Giessen, Giessen, Germany
| | - Turgun Toktash
- Medical Department, Kumtor Gold Company, Bishkek, Kyrgyzstan
| | - Anara Doolotova
- Medical Department, Kumtor Gold Company, Bishkek, Kyrgyzstan
| | - Akpay Sarybaev
- Department of Mountain and Sleep Medicine and Pulmonary Hypertension, National Center of Cardiology and Internal Medicine, Bishkek, Kyrgyzstan.,Kyrgyz Indian Mountain Biomedical Research Center, Bishkek, Kyrgyzstan
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