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Patrician A, Anholm JD, Ainslie PN. A narrative review of periodic breathing during sleep at high altitude: From acclimatizing lowlanders to adapted highlanders. J Physiol 2024. [PMID: 38534039 DOI: 10.1113/jp285427] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2023] [Accepted: 02/15/2024] [Indexed: 03/28/2024] Open
Abstract
Periodic breathing during sleep at high altitude is almost universal among sojourners. Here, in the context of acclimatization and adaptation, we provide a contemporary review on periodic breathing at high altitude, and explore whether this is an adaptive or maladaptive process. The mechanism(s), prevalence and role of periodic breathing in acclimatized lowlanders at high altitude are contrasted with the available data from adapted indigenous populations (e.g. Andean and Tibetan highlanders). It is concluded that (1) periodic breathing persists with acclimatization in lowlanders and the severity is proportional to sleeping altitude; (2) periodic breathing does not seem to coalesce with poor sleep quality such that, with acclimatization, there appears to be a lengthening of cycle length and minimal impact on the average sleeping oxygen saturation; and (3) high altitude adapted highlanders appear to demonstrate a blunting of periodic breathing, compared to lowlanders, comprising a feature that withstands the negative influences of chronic mountain sickness. These observations indicate that periodic breathing persists with high altitude acclimatization with no obvious negative consequences; however, periodic breathing is attenuated with high altitude adaptation and therefore potentially reflects an adaptive trait to this environment.
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Affiliation(s)
- Alexander Patrician
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan, Kelowna, BC, Canada
| | - James D Anholm
- Department of Medicine, Division of Pulmonary and Critical Care, Loma Linda University School of Medicine, Loma Linda, CA, USA
| | - Philip N Ainslie
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan, Kelowna, BC, Canada
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2
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Champigneulle B, Brugniaux JV, Stauffer E, Doutreleau S, Furian M, Perger E, Pina A, Baillieul S, Deschamps B, Hancco I, Connes P, Robach P, Pichon A, Verges S. Expedition 5300: limits of human adaptations in the highest city in the world. J Physiol 2023. [PMID: 38146929 DOI: 10.1113/jp284550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Accepted: 12/06/2023] [Indexed: 12/27/2023] Open
Abstract
Exposure to chronic hypobaric hypoxia imposes a significant physiological burden to more than 80 million humans living above 2500 m throughout the world. Among them, 50 000 live in the world's highest city, La Rinconada, located at 5000-5300 m in southern Peru. Expedition 5300 is the first scientific and medical programme led in La Rinconada to investigate the physiological adaptations and altitude-related health issues in this unique population. Dwellers from La Rinconada have very high haemoglobin concentration (20.3 ± 2.4 g/dL; n = 57) and those with chronic mountain sickness (CMS) exhibit even higher concentrations (23.1 ± 1.7 g/dL; n = 150). These values are associated with large total haemoglobin mass and blood volume, without an associated iron deficit. These changes in intravascular volumes lead to a substantial increase in blood viscosity, which is even larger in CMS patients. Despite these large haematological changes, 24 h blood pressure monitoring is essentially normal in La Rinconada, but some results suggest impaired vascular reactivity. Echocardiography revealed large right heart dilatation and high pulmonary arterial pressure as well as left ventricle concentric remodelling and grade I diastolic dysfunction. These changes in heart dimension and function tend to be more severe in highlanders with CMS. Polygraphy evaluations revealed a large reduction in nocturnal pulse oxygen saturation (median SpO2 = 79%), which is even more severe in CMS patients who also tended to show a higher oxygen desaturation index. The population of La Rinconada offers a unique opportunity to investigate the human responses to chronic severe hypoxia, at an altitude that is probably close to the maximum altitude human beings can permanently tolerate without presenting major health issues.
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Affiliation(s)
- Benoit Champigneulle
- Univ. Grenoble Alpes, Inserm, CHU Grenoble Alpes, HP2 laboratory, Grenoble, France
| | - Julien V Brugniaux
- Univ. Grenoble Alpes, Inserm, CHU Grenoble Alpes, HP2 laboratory, 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
| | - Stéphane Doutreleau
- Univ. Grenoble Alpes, Inserm, CHU Grenoble Alpes, HP2 laboratory, Grenoble, France
| | - Michael Furian
- Univ. Grenoble Alpes, Inserm, CHU Grenoble Alpes, HP2 laboratory, Grenoble, France
| | - Elisa Perger
- Istituto Auxologico Italiano, IRCCS, Sleep Disorders Center & Department of Cardiovascular, Neural and Metabolic Sciences, San Luca Hospital, Milan, Italy
| | - Alessandra Pina
- Istituto Auxologico Italiano, IRCCS, Sleep Disorders Center & Department of Cardiovascular, Neural and Metabolic Sciences, San Luca Hospital, Milan, Italy
| | - Sébastien Baillieul
- Univ. Grenoble Alpes, Inserm, CHU Grenoble Alpes, HP2 laboratory, Grenoble, France
| | - Blandine Deschamps
- Univ. Grenoble Alpes, Inserm, CHU Grenoble Alpes, HP2 laboratory, Grenoble, France
| | - Ivan Hancco
- Univ. Grenoble Alpes, Inserm, CHU Grenoble Alpes, HP2 laboratory, Grenoble, France
| | - Philippe Connes
- Interuniversity Laboratory of Human Movement Biology (LIBM, EA7424), "Red Blood cell and Vascular Biology" Team, Univ Lyon - University Claude Bernard Lyon 1, Villeurbanne, France
| | - Paul Robach
- Univ. Grenoble Alpes, Inserm, CHU Grenoble Alpes, HP2 laboratory, Grenoble, France
- National School for Mountain Sports, Site of the National School for Skiing and Mountaineering (ENSA), Chamonix, France
| | - Aurélien Pichon
- Laboratory Mobility, Aging & Exercise (MOVE, EA6314), Faculty of Sport Sciences, University of Poitiers, Poitiers, France
| | - Samuel Verges
- Univ. Grenoble Alpes, Inserm, CHU Grenoble Alpes, HP2 laboratory, Grenoble, France
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Niclou A, Sarma M, Levy S, Ocobock C. To the extreme! How biological anthropology can inform exercise physiology in extreme environments. Comp Biochem Physiol A Mol Integr Physiol 2023; 284:111476. [PMID: 37423419 DOI: 10.1016/j.cbpa.2023.111476] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2023] [Revised: 07/03/2023] [Accepted: 07/04/2023] [Indexed: 07/11/2023]
Abstract
The fields of biological anthropology and exercise physiology are closely related and can provide mutually beneficial insights into human performance. These fields often use similar methods and are both interested in how humans function, perform, and respond in extreme environments. However, these two fields have different perspectives, ask different questions, and work within different theoretical frameworks and timescales. Biological anthropologists and exercise physiologists can greatly benefit from working together when examining human adaptation, acclimatization, and athletic performance in the extremes of heat, cold, and high-altitude. Here we review the adaptations and acclimatizations in these three different extreme environments. We then examine how this work has informed and built upon exercise physiology research on human performance. Finally, we present an agenda for moving forward, hopefully, with these two fields working more closely together to produce innovative research that improves our holistic understanding of human performance capacities informed by evolutionary theory, modern human acclimatization, and the desire to produce immediate and direct benefits.
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Affiliation(s)
- Alexandra Niclou
- Pennington Biomedical Research Center, Baton Rouge, LA, United States of America. https://twitter.com/fiat_luxandra
| | - Mallika Sarma
- Human Space Flight Lab, Johns Hopkins School of Medicine, Baltimore, MD, United States of America. https://twitter.com/skyy_mal
| | - Stephanie Levy
- Department of Anthropology, CUNY Hunter College, New York, NY, United States of America; New York Consortium in Evolutionary Primatology, New York, NY, United States of America. https://twitter.com/slevyscience
| | - Cara Ocobock
- University of Notre Dame Department of Anthropology, Notre Dame, IN, United States of America; Eck Institute for Global Health, Institute for Educational Initiatives, University of Notre Dame, United States of America.
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4
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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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5
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Sanchez-Azofra A, Villafuerte FC, DeYoung PN, Gilbertson D, Gu W, Moya EA, Vizcardo-Galindo G, Figueroa-Mujíca R, Anza-Ramirez C, Macarlupú JL, Pham LV, Wagner P, Malhotra A, Simonson TS, Mesarwi OA. Isovolemic hemodilution in chronic mountain sickness acutely worsens nocturnal oxygenation and sleep apnea severity. J Clin Sleep Med 2022; 18:2423-2432. [PMID: 35855526 PMCID: PMC9516589 DOI: 10.5664/jcsm.10136] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 06/02/2022] [Accepted: 06/02/2022] [Indexed: 11/13/2022]
Abstract
STUDY OBJECTIVES Chronic mountain sickness (CMS) is commonly observed among Andean and other highland populations. Sleep-disordered breathing (SDB) is highly prevalent at high altitude, and SDB and nocturnal hypoxemia have been observed in CMS. Phlebotomy is commonly performed to treat CMS, but it is unknown whether reducing hematocrit improves SDB. We hypothesized that isovolemic hemodilution (IVHD) in CMS would reduce SBD severity and improve sleep efficiency. METHODS Six participants with CMS and 8 without CMS, all residents of Cerro de Pasco, Peru (altitude 4340 m), completed baseline nocturnal sleep studies. CMS participants then underwent IVHD, and nocturnal sleep studies were repeated 24-48 hours after IVHD. We analyzed sleep apnea severity, nocturnal oxygenation, and sleep quality in those with CMS relative to those without CMS, and the effects of IVHD in CMS participants. RESULTS Participants with CMS did not have altered sleep architecture, sleep apnea severity, or nocturnal oxygenation relative to non-CMS participants. However, IVHD in CMS increased apnea-hypopnea index (40.9 ± 6.9 events/h to 61.5 ± 7.7 events/h, P = .009). IVHD increased oxyhemoglobin desaturation index (P = .008) and the percentage of sleep time spent with oxyhemoglobin saturation at or below 80% (P = .012). There was no effect of IVHD on sleep efficiency, arousal index, or sleep staging. CONCLUSIONS In this cohort, CMS was not associated with worsened SDB or changes in sleep architecture. IVHD, a putative therapeutic option for participants with CMS, appears to worsen nocturnal oxygenation and SDB within 48 hours post-IVHD. CITATION Sanchez-Azofra A, Villafuerte FC, DeYoung PN, et al. Isovolemic hemodilution in chronic mountain sickness acutely worsens nocturnal oxygenation and sleep apnea severity. J Clin Sleep Med. 2022;18(10):2423-2432.
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Affiliation(s)
- Ana Sanchez-Azofra
- Division of Pulmonary, Critical Care, & Sleep Medicine and Physiology, Department of Medicine, University of California, San Diego, California
- Servicio de Neumología, Hospital Universitario de la Princesa, Universidad Autónoma de Madrid, Madrid, España
| | - Francisco C. Villafuerte
- Laboratorio de Fisiología Comparada, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Perú
| | - Pamela N. DeYoung
- Division of Pulmonary, Critical Care, & Sleep Medicine and Physiology, Department of Medicine, University of California, San Diego, California
| | - Dillon Gilbertson
- Division of Pulmonary, Critical Care, & Sleep Medicine and Physiology, Department of Medicine, University of California, San Diego, California
| | - Wanjun Gu
- Division of Pulmonary, Critical Care, & Sleep Medicine and Physiology, Department of Medicine, University of California, San Diego, California
| | - Esteban A. Moya
- Division of Pulmonary, Critical Care, & Sleep Medicine and Physiology, Department of Medicine, University of California, San Diego, California
| | - 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
| | - Cecilia Anza-Ramirez
- Laboratorio de Fisiología Comparada, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Perú
| | - Jose L. Macarlupú
- Laboratorio de Fisiología Comparada, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Perú
| | - Luu V. Pham
- Division of Pulmonary and Critical Care Medicine, Johns Hopkins University, Baltimore, Maryland
| | - Peter Wagner
- Division of Pulmonary, Critical Care, & Sleep Medicine and Physiology, Department of Medicine, University of California, San Diego, California
| | - Atul Malhotra
- Division of Pulmonary, Critical Care, & Sleep Medicine and Physiology, Department of Medicine, University of California, San Diego, California
- Center for Physiological Genomics of Low Oxygen, University of California, San Diego, California
| | - Tatum S. Simonson
- Division of Pulmonary, Critical Care, & Sleep Medicine and Physiology, Department of Medicine, University of California, San Diego, California
- Center for Physiological Genomics of Low Oxygen, University of California, San Diego, California
| | - Omar A. Mesarwi
- Division of Pulmonary, Critical Care, & Sleep Medicine and Physiology, Department of Medicine, University of California, San Diego, California
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6
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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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7
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Bao H, He X, Wang F, Kang D. Study of Brain Structure and Function in Chronic Mountain Sickness Based on fMRI. Front Neurol 2022; 12:763835. [PMID: 35069409 PMCID: PMC8777079 DOI: 10.3389/fneur.2021.763835] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Accepted: 12/08/2021] [Indexed: 12/21/2022] Open
Abstract
Objective: Headache and memory impairment are the primary clinical symptoms of chronic mountain sickness (CMS). In this study, we used voxel-based morphometry (VBM) and the amplitude of the low-frequency fluctuation method (ALFF) based on blood oxygen level-dependent functional magnetic resonance imaging (BOLD-fMRI) to identify changes in the brain structure and function caused by CMS. Materials and Methods: T1W anatomical images and a resting-state functional MRI (fMRI) of the whole brain were performed in 24 patients diagnosed with CMS and 25 normal controls matched for age, sex, years of education, and living altitude. MRI images were acquired, followed by VBM and ALFF data analyses. Results: Compared with the control group, the CMS group had increased gray matter volume in the left cerebellum crus II area, left inferior temporal gyrus, right middle temporal gyrus, right insula, right caudate nucleus, and bilateral lentiform nucleus along with decreased gray matter volume in the left middle occipital gyrus and left middle temporal gyrus. White matter was decreased in the bilateral middle temporal gyrus and increased in the right Heschl's gyrus. Resting-state fMRI in patients with CMS showed increased spontaneous brain activity in the left supramarginal gyrus, left parahippocampal gyrus, and left middle temporal gyrus along with decreased spontaneous brain activity in the right cerebellum crus I area and right supplementary motor area. Conclusion: Patients with CMS had differences in gray and white matter volume and abnormal spontaneous brain activity in multiple brain regions compared to the controls. This suggests that long-term chronic hypoxia may induce changes in brain structure and function, resulting in CMS.
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Affiliation(s)
- Haihua Bao
- Department of Medical Imaging Center, Qinghai University Affiliated Hospital, Xining, China
| | - Xin He
- Department of Medical Imaging Center, Qinghai University Affiliated Hospital, Xining, China
| | - Fangfang Wang
- Department of Medical Imaging Center, Qinghai University Affiliated Hospital, Xining, China
| | - Dongjie Kang
- Department of Medical Imaging Center, Qinghai University Affiliated Hospital, Xining, China
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8
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Lovering AT, Kelly TS, DiMarco KG, Bradbury KE, Charkoudian N. Implications of a patent foramen ovale on environmental physiology and pathophysiology: Do we know the hole story? J Physiol 2022; 600:1541-1553. [PMID: 35043424 DOI: 10.1113/jp281108] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 01/14/2022] [Indexed: 11/08/2022] Open
Abstract
The foramen ovale is an essential component of the foetal circulation contributing to oxygenation and carbon dioxide elimination that remains patent under certain circumstances, in ∼ 30% of the healthy adult population, without major negative sequelae in most. Adults with a patent foramen ovale (PFO) have a greater tendency to develop symptoms of acute mountain sickness and high-altitude pulmonary oedema upon ascent to high altitude, and PFO presence is associated with worse cardiopulmonary function in chronic mountain sickness. This increase in altitude illness prevalence may be related to dysregulated cerebral blood flow associated with altered respiratory chemoreflex sensitivity; however, the mechanisms remain to be elucidated. Interestingly, men with a PFO appear to have a shift in thermoregulatory control to higher internal temperatures, both at rest and during exercise, and they have blunted thermal tachypnea. The teleological "reason" for this thermoregulatory shift is unclear, but the shift of ∼0.5°C in core body temperature does not appear to be sufficient to have any significant negative consequences in terms of risk of heat illness. Further work in this area is needed, particularly in women, to evaluate mechanisms of heat storage and dissipation in these individuals as compared to people without a PFO. Consequences of a PFO in SCUBA divers include a greater incidence of unprovoked decompression sickness, but whether PFO is beneficial or detrimental to breath hold diving remains unexplored. Whether PFO presence will explain interindividual variability in responses to, and consequences from, other environmental stressors such as spaceflight remain entirely unknown. Abstract figure legend Associations between PFO and altitude illnesses, core body temperature and diving. This article is protected by copyright. All rights reserved.
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Affiliation(s)
| | - Tyler S Kelly
- University of Oregon, Department of Human Physiology, Eugene, OR
| | | | - Karleigh E Bradbury
- University of Oregon, Department of Human Physiology, Eugene, OR.,United States Army Research Institute of Environmental Medicine, Thermal & Mountain Medicine Division, Natick, MA
| | - Nisha Charkoudian
- United States Army Research Institute of Environmental Medicine, Thermal & Mountain Medicine Division, Natick, MA
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9
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Tan L, Li T, Luo L, Xue X, Lei F, Ren R, Zhang Y, He J, Bloch KE, Tang X. The Characteristics of Sleep Apnea in Tibetans and Han Long-Term High Altitude Residents. Nat Sci Sleep 2022; 14:1533-1544. [PMID: 36072275 PMCID: PMC9444001 DOI: 10.2147/nss.s371388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Accepted: 08/23/2022] [Indexed: 11/29/2022] Open
Abstract
PURPOSE Obstructive sleep apnea (OSA) is common both at low and high altitude. Since adaptations to high altitude and respiratory control may differ among Tibetans and Hans, we compared characteristics of sleep-disordered breathing in the two ethnic groups at high altitude. MATERIALS AND METHODS This was a prospective observational study including 86 Tibetan and Han long-term (>5 years) high altitude residents with chief complaints of snoring and/or witnessed apnea underwent clinical evaluation and polysomnography at 3200 meters in Shangri-La, China. RESULTS In 42 Tibetans, 38 men, median (quartiles) age was 50.0 (41.0; 56.0)y, total apnea/hypopnea index (AHI) 53.9 (32.0; 77.5)/h, obstructive AHI 51.0 (28.0; 72.2)/h and central AHI 1.5 (0.2; 3.1)/h. In 44 Hans, 32 men, median (quartiles) age was 47.0 (43.5; 51.0)y, total AHI 22.2 (12.8; 39.2)/h, obstructive AHI 17.7 (12.0; 33.0)/h and central AHI 2.4 (0.5; 3.4)/h (p < 0.001 total and obstructive AHI vs Tibetans). In Tibetans, mean nocturnal oxygen saturation was lower [median 85.0 (83.0; 88.0)% vs 88.5 (87.0; 90.0)%] and obstructive apnea and hypopnea duration was longer [22.0 (19.6; 24.8) sec vs 18.3 (16.7; 20.6) sec] than in Hans (all p < 0.001). In regression analysis, Tibetan ethnicity, neck circumference and high-altitude living duration were the predictors of total AHI. We also found that with every 10/h increase in total AHI, there were an approximately 0.9 beat/min and 0.8 beat/min increase in mean heart rate during rapid eye movement (REM) and non-REM sleep and 1.9 mmHg and 2.0 mmHg increase in evening and morning systolic blood pressure. CONCLUSION Our data suggest that Tibetans presented more severe obstructive sleep apnea, hypoxemia and longer apnea duration compared to Hans at 3200 meters, which was correlated with higher heart rate and blood pressure suggesting a greater cardiovascular risk.
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Affiliation(s)
- Lu Tan
- Sleep Medicine Center, West China Hospital, Sichuan University, Chengdu, People's Republic of China
| | - Taomei Li
- Sleep Medicine Center, West China Hospital, Sichuan University, Chengdu, People's Republic of China
| | - Lian Luo
- Sleep Medicine Center, West China Hospital, Sichuan University, Chengdu, People's Republic of China
| | - Xiaofang Xue
- Department of Emergency, Diqing Tibetan Autonomous Prefectural People's Hospital, Shangri-La, People's Republic of China.,Department of Intensive Care Unit, Diqing Tibetan Autonomous Prefectural People's Hospital, Shangri-La, People's Republic of China
| | - Fei Lei
- Sleep Medicine Center, West China Hospital, Sichuan University, Chengdu, People's Republic of China
| | - Rong Ren
- Sleep Medicine Center, West China Hospital, Sichuan University, Chengdu, People's Republic of China
| | - Ye Zhang
- Sleep Medicine Center, West China Hospital, Sichuan University, Chengdu, People's Republic of China
| | - Jiaming He
- Department of Emergency, Diqing Tibetan Autonomous Prefectural People's Hospital, Shangri-La, People's Republic of China.,Department of Intensive Care Unit, Diqing Tibetan Autonomous Prefectural People's Hospital, Shangri-La, People's Republic of China
| | - Konrad E Bloch
- Department of Respiratory Medicine, Sleep Disorders Center, University Hospital of Zurich, Zurich, Switzerland
| | - Xiangdong Tang
- Sleep Medicine Center, West China Hospital, Sichuan University, Chengdu, People's Republic of China.,Mental Health Center, West China Hospital, Sichuan University, Chengdu, People's Republic of China.,Department of Respiratory and Critical Care Medicine, West China Hospital, Sichuan University, Chengdu, People's Republic of China.,State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, People's Republic of China
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10
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Garrido E, Botella de Maglia J, Castillo O. Acute, subacute and chronic mountain sickness. Rev Clin Esp 2021; 221:481-490. [PMID: 34583826 DOI: 10.1016/j.rceng.2019.12.009] [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] [Received: 10/16/2019] [Accepted: 12/16/2019] [Indexed: 11/29/2022]
Abstract
More than 100 million people ascend to high mountainous areas worldwide every year. At nonextreme altitudes (<5500m), 10-85% of these individuals are affected by acute mountain sickness, the most common disease induced by mild-moderate hypobaric hypoxia. Approximately 140 million individuals live permanently at heights of 2500-5500m, and up to 10% of them are affected by the subacute form of mountain sickness (high-altitude pulmonary hypertension) or the chronic form (Monge's disease), the latter of which is especially common in Andean ethnicities. This review presents the most relevant general concepts of these 3 clinical variants, which can be incapacitating and can result in complications and become life-threatening. Proper prevention, diagnosis, treatment and management of these conditions in a hostile environment such as high mountains are therefore essential.
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Affiliation(s)
- E Garrido
- Servicio de Hipobaria y Fisiología Biomédica, Universidad de Barcelona, L'Hospitalet de Llobregat, Barcelona, Spain; Instituto de Estudios de Medicina de Montaña (IEMM), Barcelona, Spain.
| | - J Botella de Maglia
- Servicio de Medicina Intensiva, Hospital Universitario y Politécnico La Fe, Valencia, Spain; Instituto de Estudios de Medicina de Montaña (IEMM), Barcelona, Spain
| | - O Castillo
- Instituto Nacional de Biología Andina, Universidad Nacional Mayor de San Marcos, Lima, Peru
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11
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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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12
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Garrido E, Botella de Maglia J, Castillo O. Acute, subacute and chronic mountain sickness. Rev Clin Esp 2020; 221:S0014-2565(20)30064-3. [PMID: 32197780 DOI: 10.1016/j.rce.2019.12.013] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Accepted: 12/16/2019] [Indexed: 11/20/2022]
Abstract
More than 100 million people ascend to high mountainous areas worldwide every year. At nonextreme altitudes (<5500 m), 10-85% of these individuals are affected by acute mountain sickness, the most common disease induced by mild-moderate hypobaric hypoxia. Approximately 140 million individuals live permanently at heights of 2500-5500 m, and up to 10% of them are affected by the subacute form of mountain sickness (high-altitude pulmonary hypertension) or the chronic form (Monge's disease), the latter of which is especially common in Andean ethnicities. This review presents the most relevant general concepts of these 3 clinical variants, which can be incapacitating and can result in complications and become life-threatening. Proper prevention, diagnosis, treatment and management of these conditions in a hostile environment such as high mountains are therefore essential.
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Affiliation(s)
- E Garrido
- Servicio de Hipobaria y Fisiología Biomédica, Universidad de Barcelona, L'Hospitalet de Llobregat, Barcelona, España; Instituto de Estudios de Medicina de Montaña (IEMM), Barcelona, España.
| | - J Botella de Maglia
- Servicio de Medicina Intensiva, Hospital Universitario y Politécnico La Fe, Valencia, España; Instituto de Estudios de Medicina de Montaña (IEMM), Barcelona, España
| | - O Castillo
- Instituto Nacional de Biología Andina, Universidad Nacional Mayor de San Marcos, Lima, Perú
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13
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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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14
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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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15
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Soria R, Egger M, Scherrer U, Bender N, Rimoldi SF. Pulmonary arterial pressure at rest and during exercise in chronic mountain sickness: a meta-analysis. Eur Respir J 2019; 53:13993003.02040-2018. [PMID: 31023845 DOI: 10.1183/13993003.02040-2018] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Accepted: 03/21/2019] [Indexed: 01/22/2023]
Abstract
Up to 10% of the more than 140 million high-altitude dwellers worldwide suffer from chronic mountain sickness (CMS). Patients suffering from this debilitating problem often display increased pulmonary arterial pressure (PAP), which may contribute to exercise intolerance and right heart failure. However, there is little information on the usual PAP in these patients.We systematically reviewed and meta-analysed all data published in English or Spanish until June 2018 on echocardiographic estimations of PAP at rest and during mild exercise in CMS patients.Nine studies comprising 287 participants fulfilled the inclusion criteria. At rest, the point estimate from meta-analysis of the mean systolic PAP was 27.9 mmHg (95% CI 26.3-29.6 mmHg). These values are 11% (+2.7 mmHg) higher than those previously meta-analysed in apparently healthy high-altitude dwellers. During mild exercise (50 W) the difference in mean systolic PAP between patients and high-altitude dwellers was markedly more accentuated (48.3 versus 36.3 mmHg) than at rest.These findings indicate that in patients with CMS PAP is moderately increased at rest, but markedly increased during mild exercise, which will be common with activities of daily living.
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Affiliation(s)
- Rodrigo Soria
- Dept of Cardiology and Clinical Research, Inselspital, University of Bern, Bern, Switzerland
| | - Matthias Egger
- Institute of Social and Preventive Medicine (ISPM), University of Bern, Bern, Switzerland.,Division of Epidemiology and Biostatistics, School of Public Health and Family Medicine, University of Cape Town, Cape Town, South Africa
| | - Urs Scherrer
- Dept of Cardiology and Clinical Research, Inselspital, University of Bern, Bern, Switzerland.,Facultad de Ciencias, Departamento de Biología, Universidad de Tarapacá, Arica, Chile
| | - Nicole Bender
- Institute of Social and Preventive Medicine (ISPM), University of Bern, Bern, Switzerland.,Institute of Evolutionary Medicine, University of Zurich, Zurich, Switzerland.,These two authors contributed equally to this work
| | - Stefano F Rimoldi
- Dept of Cardiology and Clinical Research, Inselspital, University of Bern, Bern, Switzerland .,These two authors contributed equally to this work
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16
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Sleep Disordered Breathing at High Altitude in Adults and Its Interaction with Cardiovascular Homeostasis. CURRENT SLEEP MEDICINE REPORTS 2019. [DOI: 10.1007/s40675-019-00138-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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17
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Human Genetic Adaptation to High Altitude: Evidence from the Andes. Genes (Basel) 2019; 10:genes10020150. [PMID: 30781443 PMCID: PMC6410003 DOI: 10.3390/genes10020150] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Revised: 01/29/2019] [Accepted: 02/11/2019] [Indexed: 12/31/2022] Open
Abstract
Whether Andean populations are genetically adapted to high altitudes has long been of interest. Initial studies focused on physiological changes in the O₂ transport system that occur with acclimatization in newcomers and their comparison with those of long-resident Andeans. These as well as more recent studies indicate that Andeans have somewhat larger lung volumes, narrower alveolar to arterial O₂ gradients, slightly less hypoxic pulmonary vasoconstrictor response, greater uterine artery blood flow during pregnancy, and increased cardiac O2 utilization, which overall suggests greater efficiency of O₂ transfer and utilization. More recent single nucleotide polymorphism and whole-genome sequencing studies indicate that multiple gene regions have undergone recent positive selection in Andeans. These include genes involved in the regulation of vascular control, metabolic hemostasis, and erythropoiesis. However, fundamental questions remain regarding the functional links between these adaptive genomic signals and the unique physiological attributes of highland Andeans. Well-designed physiological and genome association studies are needed to address such questions. It will be especially important to incorporate the role of epigenetic processes (i.e.; non-sequence-based features of the genome) that are vital for transcriptional responses to hypoxia and are potentially heritable across generations. In short, further exploration of the interaction among genetic, epigenetic, and environmental factors in shaping patterns of adaptation to high altitude promises to improve the understanding of the mechanisms underlying human adaptive potential and clarify its implications for human health.
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18
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Bailey DM, Brugniaux JV, Filipponi T, Marley CJ, Stacey B, Soria R, Rimoldi SF, Cerny D, Rexhaj E, Pratali L, Salmòn CS, Murillo Jáuregui C, Villena M, Smirl JD, Ogoh S, Pietri S, Scherrer U, Sartori C. Exaggerated systemic oxidative-inflammatory-nitrosative stress in chronic mountain sickness is associated with cognitive decline and depression. J Physiol 2019; 597:611-629. [PMID: 30397919 PMCID: PMC6332753 DOI: 10.1113/jp276898] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Accepted: 11/05/2018] [Indexed: 12/15/2022] Open
Abstract
KEY POINTS Chronic mountain sickness (CMS) is a maladaptation syndrome encountered at high altitude (HA) characterised by severe hypoxaemia that carries a higher risk of stroke and migraine and is associated with increased morbidity and mortality. We examined if exaggerated oxidative-inflammatory-nitrosative stress (OXINOS) and corresponding decrease in vascular nitric oxide bioavailability in patients with CMS (CMS+) is associated with impaired cerebrovascular function and adverse neurological outcome. Systemic OXINOS was markedly elevated in CMS+ compared to healthy HA (CMS-) and low-altitude controls. OXINOS was associated with blunted cerebral perfusion and vasoreactivity to hypercapnia, impaired cognition and, in CMS+, symptoms of depression. These findings are the first to suggest that a physiological continuum exists for hypoxaemia-induced systemic OXINOS in HA dwellers that when excessive is associated with accelerated cognitive decline and depression, helping identify those in need of more specialist neurological assessment and targeted support. ABSTRACT Chronic mountain sickness (CMS) is a maladaptation syndrome encountered at high altitude (HA) characterised by severe hypoxaemia that carries a higher risk of stroke and migraine and is associated with increased morbidity and mortality. The present cross-sectional study examined to what extent exaggerated systemic oxidative-inflammatory-nitrosative stress (OXINOS), defined by an increase in free radical formation and corresponding decrease in vascular nitric oxide (NO) bioavailability, is associated with impaired cerebrovascular function, accelerated cognitive decline and depression in CMS. Venous blood was obtained from healthy male lowlanders (80 m, n = 17), and age- and gender-matched HA dwellers born and bred in La Paz, Bolivia (3600 m) with (CMS+, n = 23) and without (CMS-, n = 14) CMS. We sampled blood for oxidative (electron paramagnetic resonance spectroscopy, HPLC), nitrosative (ozone-based chemiluminescence) and inflammatory (fluorescence) biomarkers. We employed transcranial Doppler ultrasound to measure cerebral blood flow (CBF) and reactivity. We utilised psychometric tests and validated questionnaires to assess cognition and depression. Highlanders exhibited elevated systemic OXINOS (P < 0.05 vs. lowlanders) that was especially exaggerated in the more hypoxaemic CMS+ patients (P < 0.05 vs. CMS-). OXINOS was associated with blunted cerebral perfusion and vasoreactivity to hypercapnia, impaired cognition and, in CMS+, symptoms of depression. Collectively, these findings are the first to suggest that a physiological continuum exists for hypoxaemia-induced OXINOS in HA dwellers that when excessive is associated with accelerated cognitive decline and depression, helping identify those in need of specialist neurological assessment and support.
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Affiliation(s)
- Damian M. Bailey
- Neurovascular Research LaboratoryFaculty of Life Sciences and Education, University of South WalesUK
| | - Julien V. Brugniaux
- Neurovascular Research LaboratoryFaculty of Life Sciences and Education, University of South WalesUK
- HP2 Laboratory, INSERM U1042Grenoble Alpes UniversityGrenobleFrance
| | - Teresa Filipponi
- Neurovascular Research LaboratoryFaculty of Life Sciences and Education, University of South WalesUK
| | - Christopher J. Marley
- Neurovascular Research LaboratoryFaculty of Life Sciences and Education, University of South WalesUK
| | - Benjamin Stacey
- Neurovascular Research LaboratoryFaculty of Life Sciences and Education, University of South WalesUK
| | - Rodrigo Soria
- Department of Cardiology and Clinical ResearchUniversity HospitalBernSwitzerland
| | - Stefano F. Rimoldi
- Department of Cardiology and Clinical ResearchUniversity HospitalBernSwitzerland
| | - David Cerny
- Department of Cardiology and Clinical ResearchUniversity HospitalBernSwitzerland
| | - Emrush Rexhaj
- Department of Cardiology and Clinical ResearchUniversity HospitalBernSwitzerland
| | | | | | | | | | - Jonathan D. Smirl
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise ScienceUniversity of British Columbia OkanaganKelownaBritish ColumbiaCanada
| | | | | | - Urs Scherrer
- Department of Cardiology and Clinical ResearchUniversity HospitalBernSwitzerland
- Facultad de Ciencias, Departamento de BiologíaUniversidad de TarapacáAricaChile
| | - Claudio Sartori
- Department of Internal MedicineUniversity HospitalUNIL‐LausanneSwitzerland
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19
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Alarcón-Yaquetto DE, Caballero L, Gonzales GF. Association Between Plasma N-Acylethanolamides and High Hemoglobin Concentration in Southern Peruvian Highlanders. High Alt Med Biol 2017; 18:322-329. [DOI: 10.1089/ham.2016.0148] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Dulce E. Alarcón-Yaquetto
- Department of Biological and Physiological Sciences, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Lidia Caballero
- Research Circle of Plants with Effects on Health, Universidad Peruana Cayetano Heredia, Lima, Peru
- Universidad Nacional del Altiplano, Puno, Peru
| | - Gustavo F. Gonzales
- Department of Biological and Physiological Sciences, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
- Research Circle of Plants with Effects on Health, Universidad Peruana Cayetano Heredia, Lima, Peru
- Instituto de Investigaciones en Altura, Universidad Peruana Cayetano Heredia, Lima, Peru
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20
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Moore LG. Measuring high-altitude adaptation. J Appl Physiol (1985) 2017; 123:1371-1385. [PMID: 28860167 DOI: 10.1152/japplphysiol.00321.2017] [Citation(s) in RCA: 113] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Revised: 08/15/2017] [Accepted: 08/15/2017] [Indexed: 12/12/2022] Open
Abstract
High altitudes (>8,000 ft or 2,500 m) provide an experiment of nature for measuring adaptation and the physiological processes involved. Studies conducted over the past ~25 years in Andeans, Tibetans, and, less often, Ethiopians show varied but distinct O2 transport traits from those of acclimatized newcomers, providing indirect evidence for genetic adaptation to high altitude. Short-term (acclimatization, developmental) and long-term (genetic) responses to high altitude exhibit a temporal gradient such that, although all influence O2 content, the latter also improve O2 delivery and metabolism. Much has been learned concerning the underlying physiological processes, but additional studies are needed on the regulation of blood flow and O2 utilization. Direct evidence of genetic adaptation comes from single-nucleotide polymorphism (SNP)-based genome scans and whole genome sequencing studies that have identified gene regions acted upon by natural selection. Efforts have begun to understand the connections between the two with Andean studies on the genetic factors raising uterine blood flow, fetal growth, and susceptibility to Chronic Mountain Sickness and Tibetan studies on genes serving to lower hemoglobin and pulmonary arterial pressure. Critical for future studies will be the selection of phenotypes with demonstrable effects on reproductive success, the calculation of actual fitness costs, and greater inclusion of women among the subjects being studied. The well-characterized nature of the O2 transport system, the presence of multiple long-resident populations, and relevance for understanding hypoxic disorders in all persons underscore the importance of understanding how evolutionary adaptation to high altitude has occurred.NEW & NOTEWORTHY Variation in O2 transport characteristics among Andean, Tibetan, and, when available, Ethiopian high-altitude residents supports the existence of genetic adaptations that improve the distribution of blood flow to vital organs and the efficiency of O2 utilization. Genome scans and whole genome sequencing studies implicate a broad range of gene regions. Future studies are needed using phenotypes of clear relevance for reproductive success for determining the mechanisms by which naturally selected genes are acting.
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Affiliation(s)
- Lorna G Moore
- Division of Reproductive Sciences, Department of Obstetrics & Gynecology, University of Colorado Denver-Anschutz Medical Campus, Aurora, Colorado
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21
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Pramsohler S, Wimmer S, Kopp M, Gatterer H, Faulhaber M, Burtscher M, Netzer NC. Normobaric hypoxia overnight impairs cognitive reaction time. BMC Neurosci 2017; 18:43. [PMID: 28506292 PMCID: PMC5433012 DOI: 10.1186/s12868-017-0362-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Accepted: 05/10/2017] [Indexed: 01/04/2023] Open
Abstract
Background Impaired reaction time in patients suffering from hypoxia during sleep, caused by sleep breathing disorders, is a well-described phenomenon. High altitude sleep is known to induce periodic breathing with central apneas and oxygen desaturations, even in perfectly healthy subjects. However, deficits in reaction time in mountaineers or workers after just some nights of hypoxia exposure are not sufficiently explored. Therefore, we aimed to investigate the impact of sleep in a normobaric hypoxic environment on reaction time divided by its cognitive and motoric components. Eleven healthy non acclimatized students (5f, 6m, 21 ± 2.1 years) slept one night at a simulated altitude of 3500 m in a normobaric hypoxic room, followed by a night with polysomnography at simulated 5500 m. Preexisting sleep disorders were excluded via BERLIN questionnaire. All subjects performed a choice reaction test (SCHUHFRIED RT, S3) at 450 m and directly after the nights at simulated 3500 and 5500 m. Results We found a significant increase of cognitive reaction time with higher altitude (p = 0.026). No changes were detected in movement time (p = n.s.). Reaction time, the combined parameter of cognitive- and motoric reaction time, didn’t change either (p = n.s.). Lower SpO2 surprisingly correlated significantly with shorter cognitive reaction time (r = 0.78, p = 0.004). Sleep stage distribution and arousals at 5500 m didn’t correlate with reaction time, cognitive reaction time or movement time. Conclusion Sleep in hypoxia does not seem to affect reaction time to simple tasks. The component of cognitive reaction time is increasingly delayed whereas motoric reaction time seems not to be affected. Low SpO2 and arousals are not related to increased cognitive reaction time therefore the causality remains unclear. The fact of increased cognitive reaction time after sleep in hypoxia, considering high altitude workers and mountaineering operations with overnight stays, should be further investigated.
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Affiliation(s)
- Stephan Pramsohler
- Hermann Buhl Institute for Hypoxia and Sleep Medicine Research, Ghersburgstr. 9, 83043, Bad Aibling, Germany.
| | - Stefan Wimmer
- Hermann Buhl Institute for Hypoxia and Sleep Medicine Research, Ghersburgstr. 9, 83043, Bad Aibling, Germany.,Department of Sport Science, University Innsbruck, Fürstenweg 185, 6020, Innsbruck, Austria
| | - Martin Kopp
- Department of Sport Science, University Innsbruck, Fürstenweg 185, 6020, Innsbruck, Austria
| | - Hannes Gatterer
- Department of Sport Science, University Innsbruck, Fürstenweg 185, 6020, Innsbruck, Austria
| | - Martin Faulhaber
- Department of Sport Science, University Innsbruck, Fürstenweg 185, 6020, Innsbruck, Austria
| | - Martin Burtscher
- Department of Sport Science, University Innsbruck, Fürstenweg 185, 6020, Innsbruck, Austria
| | - Nikolaus Cristoph Netzer
- Hermann Buhl Institute for Hypoxia and Sleep Medicine Research, Ghersburgstr. 9, 83043, Bad Aibling, Germany.,Department of Sport Science, University Innsbruck, Fürstenweg 185, 6020, Innsbruck, Austria.,Division of Sports Medicine and Rehabilitation, Department of Medicine, University Ulm, Fürstenweg 185, Ulm, Germany
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22
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Pham LV, Meinzen C, Arias RS, Schwartz NG, Rattner A, Miele CH, Smith PL, Schneider H, Miranda JJ, Gilman RH, Polotsky VY, Checkley W, Schwartz AR. Cross-Sectional Comparison of Sleep-Disordered Breathing in Native Peruvian Highlanders and Lowlanders. High Alt Med Biol 2017; 18:11-19. [PMID: 28306414 PMCID: PMC5361758 DOI: 10.1089/ham.2016.0102] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Accepted: 01/01/2017] [Indexed: 12/16/2022] Open
Abstract
Pham, Luu V., Christopher Meinzen, Rafael S. Arias, Noah G. Schwartz, Adi Rattner, Catherine H. Miele, Philip L. Smith, Hartmut Schneider, J. Jaime Miranda, Robert H. Gilman, Vsevolod Y. Polotsky, William Checkley, and Alan R. Schwartz. Cross-sectional comparison of sleep-disordered breathing in native Peruvian highlanders and lowlanders. High Alt Med Biol. 18:11-19, 2017. BACKGROUND Altitude can accentuate sleep disordered breathing (SDB), which has been linked to cardiovascular and metabolic diseases. SDB in highlanders has not been characterized in large controlled studies. The purpose of this study was to compare SDB prevalence and severity in highlanders and lowlanders. METHODS 170 age-, body-mass-index- (BMI), and sex-matched pairs (age 58.2 ± 12.4 years, BMI 27.2 ± 3.5 kg/m2, and 86 men and 84 women) of the CRONICAS Cohort Study were recruited at a sea-level (Lima) and a high-altitude (Puno, 3825 m) setting in Peru. Participants underwent simultaneous nocturnal polygraphy and actigraphy to characterize breathing patterns, movement arousals, and sleep/wake state. We compared SDB prevalence, type, and severity between highlanders and lowlanders as measured by apnea-hypopnea index (AHI) and pulse oximetry (SPO2) during sleep. RESULTS Sleep apnea prevalence was greater in highlanders than in lowlanders (77% vs. 54%, p < 0.001). Compared with lowlanders, highlanders had twofold elevations in AHI due to increases in central rather than obstructive apneas. In highlanders compared with lowlanders, SPO2 was lower during wakefulness and decreased further during sleep (p < 0.001). Hypoxemia during wakefulness predicted sleep apnea in highlanders, and it appears to mediate the effects of altitude on sleep apnea prevalence. Surprisingly, hypoxemia was also quite prevalent in lowlanders, and it was also associated with increased odds of sleep apnea. CONCLUSIONS High altitude and hypoxemia at both high and low altitude were associated with increased SDB prevalence and severity. Our findings suggest that a large proportion of highlanders remain at risk for SDB sequelae.
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Affiliation(s)
- Luu V. Pham
- Division of Pulmonary and Critical Care and Sleep Medicine, Department of Medicine, School of Medicine, Johns Hopkins University, Baltimore, Maryland
| | - Christopher Meinzen
- Program in Global Disease Epidemiology and Control, Department of International Health, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland
| | - Rafael S. Arias
- School of Medicine, Johns Hopkins University, Baltimore, Maryland
| | - Noah G. Schwartz
- University of Chicago Pritzker School of Medicine, Chicago, Illinois
| | - Adi Rattner
- School of Medicine, Johns Hopkins University, Baltimore, Maryland
| | - Catherine H. Miele
- Division of Pulmonary and Critical Care and Sleep Medicine, Department of Medicine, School of Medicine, Johns Hopkins University, Baltimore, Maryland
| | - Philip L. Smith
- Division of Pulmonary and Critical Care and Sleep Medicine, Department of Medicine, School of Medicine, Johns Hopkins University, Baltimore, Maryland
| | - Hartmut Schneider
- Division of Pulmonary and Critical Care and Sleep Medicine, Department of Medicine, School of Medicine, Johns Hopkins University, Baltimore, Maryland
| | - J. Jaime Miranda
- School of Medicine, Universidad Peruana Cayetano Heredia, Lima, Peru
- CRONICAS Center of Excellence in Chronic Diseases, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Robert H. Gilman
- Program in Global Disease Epidemiology and Control, Department of International Health, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland
| | - Vsevolod Y. Polotsky
- Division of Pulmonary and Critical Care and Sleep Medicine, Department of Medicine, School of Medicine, Johns Hopkins University, Baltimore, Maryland
| | - William Checkley
- Division of Pulmonary and Critical Care and Sleep Medicine, Department of Medicine, School of Medicine, Johns Hopkins University, Baltimore, Maryland
- Program in Global Disease Epidemiology and Control, Department of International Health, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland
| | - Alan R. Schwartz
- Division of Pulmonary and Critical Care and Sleep Medicine, Department of Medicine, School of Medicine, Johns Hopkins University, Baltimore, Maryland
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23
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Scherrer U, Verges S. Sleep apnoea and pulmonary hypertension in high-altitude dwellers: more than an association? Eur Respir J 2017; 49:49/2/1602232. [PMID: 28153872 DOI: 10.1183/13993003.02232-2016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2016] [Accepted: 11/20/2016] [Indexed: 11/05/2022]
Affiliation(s)
- Urs Scherrer
- Dept of Cardiology, University Hospital Bern, Bern, Switzerland.,Dept of Clinical Research, University of Bern, Bern, Switzerland.,Departamento de Biología, Facultad de Ciencias, Universidad de Tarapacá, Arica, Chile
| | - Samuel Verges
- Laboratoire HP2, Université Grenoble Alpes, Grenoble, France .,Unité 1042, Institut National de la Santé et de la Recherche Médicale (INSERM), Grenoble, France
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24
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Latshang TD, Furian M, Aeschbacher SS, Ulrich S, Osmonov B, Mirrakhimov EM, Isakova J, Aldashev AA, Sooronbaev TM, Bloch KE. Association between sleep apnoea and pulmonary hypertension in Kyrgyz highlanders. Eur Respir J 2017; 49:13993003.01530-2016. [PMID: 28007792 DOI: 10.1183/13993003.01530-2016] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2016] [Accepted: 10/21/2016] [Indexed: 02/03/2023]
Abstract
This case-control study evaluates a possible association between high altitude pulmonary hypertension (HAPH) and sleep apnoea in people living at high altitude.Ninety highlanders living at altitudes >2500 m without excessive erythrocytosis and with normal spirometry were studied at 3250 m (Aksay, Kyrgyzstan); 34 healthy lowlanders living below 800 m were studied at 760 m (Bishkek, Kyrgyzstan). Echocardiography, polysomnography and other outcomes were assessed. Thirty-six highlanders with elevated mean pulmonary artery pressure (mPAP) >30 mmHg (31-42 mmHg by echocardiography) were designated as HAPH+. Their data were compared to that of 54 healthy highlanders (HH, mPAP 13-28 mmHg) and 34 healthy lowlanders (LL, mPAP 8-24 mmHg).The HAPH+ group (median age 52 years (interquartile range 47-59) had a higher apnoea-hypopnoea index (AHI) of 33.8 events·h-1 (26.9-54.6) and spent a greater percentage of the night-time with an oxygen saturation <90% (T<90; 78% (61-89)) than the HH group (median age 39 years (32-48), AHI 9.0 events·h-1 (3.6-16), T<90 33% (10-69)) and the LL group (median age 40 years (30-47), AHI 4.3 events·h-1 (1.4-12.6), T<90 0% (0-0)); p<0.007 for AHI and T<90, respectively, in HAPH+ versus others. In highlanders, multivariable regression analysis confirmed an independent association between mPAP and both AHI and T<90, when controlled for age, gender and body mass index.Pulmonary hypertension in highlanders is associated with sleep apnoea and hypoxaemia even when adjusted for age, gender and body mass index, suggesting pathophysiologic interactions between pulmonary haemodynamics and sleep apnoea.
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Affiliation(s)
- Tsogyal D Latshang
- Clinic of Pneumology and Sleep Disorders Center, University Hospital Zurich, Zurich, Switzerland
| | - Michael Furian
- Clinic of Pneumology and Sleep Disorders Center, University Hospital Zurich, Zurich, Switzerland
| | - Sayaka S Aeschbacher
- Clinic of Pneumology and Sleep Disorders Center, University Hospital Zurich, Zurich, Switzerland
| | - Silvia Ulrich
- Clinic of Pneumology and Sleep Disorders Center, University Hospital Zurich, Zurich, Switzerland
| | - Batyr Osmonov
- Dept of Respiratory, Critical Care and Sleep Medicine, National Center for Cardiology and Internal Medicine, Bishkek, Kyrgyz Republic
| | - Erkin M Mirrakhimov
- Dept of Respiratory, Critical Care and Sleep Medicine, National Center for Cardiology and Internal Medicine, Bishkek, Kyrgyz Republic.,Kyrgyz State Medical Academy, Bishkek, Kyrgyz Republic
| | - Jainagul Isakova
- Research Institute for Molecular Biology and Medicine, Bishkek, Kyrgyz Republic
| | - Almaz A Aldashev
- Research Institute for Molecular Biology and Medicine, Bishkek, Kyrgyz Republic
| | - Talant M Sooronbaev
- Dept of Respiratory, Critical Care and Sleep Medicine, National Center for Cardiology and Internal Medicine, Bishkek, Kyrgyz Republic
| | - Konrad E Bloch
- Clinic of Pneumology and Sleep Disorders Center, University Hospital Zurich, Zurich, Switzerland
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25
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Abstract
More than 140 million people permanently reside in high-altitude regions of Asia, South America, North America, and Africa. Another 40 million people travel to these places annually for occupational and recreational reasons, and are thus exposed to the low ambient partial pressure of oxygen. This review will focus on the pulmonary circulatory responses to acute and chronic high-altitude hypoxia, and the various expressions of maladaptation and disease arising from acute pulmonary vasoconstriction and subsequent remodeling of the vasculature when the hypoxic exposure continues. These unique conditions include high-altitude pulmonary edema, high-altitude pulmonary hypertension, subacute mountain sickness, and chronic mountain sickness.
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Affiliation(s)
- Maniraj Neupane
- Mountain Medicine Society of Nepal, Maharajgunj, Kathmandu, Nepal
| | - Erik R. Swenson
- Department of Medicine, Section of Pulmonary and Critical Care Medicine, VA Puget Sound Health Care System, University of Washington, Seattle, WA
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26
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Orr JE, Malhotra A, Sands SA. Pathogenesis of central and complex sleep apnoea. Respirology 2016; 22:43-52. [PMID: 27797160 DOI: 10.1111/resp.12927] [Citation(s) in RCA: 87] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Revised: 09/22/2016] [Accepted: 10/03/2016] [Indexed: 12/01/2022]
Abstract
Central sleep apnoea (CSA) - the temporary absence or diminution of ventilatory effort during sleep - is seen in a variety of forms including periodic breathing in infancy and healthy adults at altitude and Cheyne-Stokes respiration in heart failure. In most circumstances, the cyclic absence of effort is paradoxically a consequence of hypersensitive ventilatory chemoreflex responses to oppose changes in airflow, that is elevated loop gain, leading to overshoot/undershoot ventilatory oscillations. Considerable evidence illustrates overlap between CSA and obstructive sleep apnoea (OSA), including elevated loop gain in patients with OSA and the presence of pharyngeal narrowing during central apnoeas. Indeed, treatment of OSA, whether via continuous positive airway pressure (CPAP), tracheostomy or oral appliances, can reveal CSA, an occurrence referred to as complex sleep apnoea. Factors influencing loop gain include increased chemosensitivity (increased controller gain), reduced damping of blood gas levels (increased plant gain) and increased lung to chemoreceptor circulatory delay. Sleep-wake transitions and pharyngeal dilator muscle responses effectively raise the controller gain and therefore also contribute to total loop gain and overall instability. In some circumstances, for example apnoea of infancy and central congenital hypoventilation syndrome, central apnoeas are the consequence of ventilatory depression and defective ventilatory responses, that is low loop gain. The efficacy of available treatments for CSA can be explained in terms of their effects on loop gain, for example CPAP improves lung volume (plant gain), stimulants reduce the alveolar-inspired PCO2 difference and supplemental oxygen lowers chemosensitivity. Understanding the magnitude of loop gain and the mechanisms contributing to instability may facilitate personalized interventions for CSA.
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Affiliation(s)
- Jeremy E Orr
- Division of Pulmonary and Critical Care Medicine, University of California San Diego, La Jolla, California, USA
| | - Atul Malhotra
- Division of Pulmonary and Critical Care Medicine, University of California San Diego, La Jolla, California, USA
| | - Scott A Sands
- Division of Sleep and Circadian Disorders, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, USA.,Department of Allergy Immunology and Respiratory Medicine and Central Clinical School, The Alfred and Monash University, Melbourne, Victoria, Australia
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27
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Soria R, Egger M, Scherrer U, Bender N, Rimoldi SF. Pulmonary artery pressure and arterial oxygen saturation in people living at high or low altitude: systematic review and meta-analysis. J Appl Physiol (1985) 2016; 121:1151-1159. [PMID: 27660297 DOI: 10.1152/japplphysiol.00394.2016] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 09/02/2016] [Accepted: 09/21/2016] [Indexed: 02/08/2023] Open
Abstract
More than 140 million people are living at high altitude worldwide. An increase of pulmonary artery pressure (PAP) is a hallmark of high-altitude exposure and, if pronounced, may be associated with important morbidity and mortality. Surprisingly, there is little information on the usual PAP in high-altitude populations. We, therefore, conducted a systematic review (MEDLINE and EMBASE) and meta-analysis of studies published (in English or Spanish) between 2000 and 2015 on echocardiographic estimations of PAP and measurements of arterial oxygen saturation in apparently healthy participants from general populations of high-altitude dwellers (>2,500 m). For comparison, we similarly analyzed data published on these variables during the same period for populations living at low altitude. Twelve high-altitude studies comprising 834 participants and 18 low-altitude studies (710 participants) fulfilled the inclusion criteria. All but one high-altitude studies were performed between 3,600 and 4,350 m. The combined mean systolic PAP (right ventricular-to-right atrial pressure gradient) at high altitude [25.3 mmHg, 95% confidence interval (CI) 24.0, 26.7], as expected was significantly (P < 0.001) higher than at low altitude (18.4 mmHg, 95% CI 17.1,19.7), and arterial oxygen saturation was significantly lower (90.4%, 95% CI 89.3, 91.5) than at low altitude (98.1%; 95% CI 97.7, 98.4). These findings indicate that at an altitude where the very large majority of high-altitude populations are living, pulmonary hypertension appears to be rare. The reference values and distributions for PAP and arterial oxygen saturation in apparently healthy high-altitude dwellers provided by this meta-analysis will be useful to future studies on the adjustments to high altitude in humans.
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Affiliation(s)
- Rodrigo Soria
- Department of Cardiology and Clinical Research, Inselspital, University of Bern, Switzerland
| | - Matthias Egger
- Institute of Social and Preventive Medicine (ISPM), University of Bern, Switzerland.,Division of Epidemiology and Biostatistics, School of Public Health and Family Medicine, University of Cape Town, Cape Town, South Africa
| | - Urs Scherrer
- Department of Cardiology and Clinical Research, Inselspital, University of Bern, Switzerland.,Facultad de Ciencias, Departamento de Biología, Universidad de Tarapacá, Arica, Chile; and
| | - Nicole Bender
- Institute of Social and Preventive Medicine (ISPM), University of Bern, Switzerland.,Institute of Evolutionary Medicine, University of Zurich, Switzerland
| | - Stefano F Rimoldi
- Department of Cardiology and Clinical Research, Inselspital, University of Bern, Switzerland;
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28
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Villafuerte FC, Corante N, Anza-Ramírez C, Figueroa-Mujíca R, Vizcardo-Galindo G, Mercado A, Macarlupú JL, León-Velarde F. Plasma soluble erythropoietin receptor is decreased during sleep in Andean highlanders with Chronic Mountain Sickness. J Appl Physiol (1985) 2016; 121:53-8. [PMID: 27125843 PMCID: PMC4967249 DOI: 10.1152/japplphysiol.00107.2016] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 04/27/2016] [Indexed: 12/24/2022] Open
Abstract
Andean highlanders suffering from Chronic Mountain Sickness (CMS) show consistently lower levels of plasma soluble erythropoietin (Epo) receptor (sEpoR) and higher Epo-to-EpoR ratios (Epo/sEpoR) during sleep compared with their healthy counterparts. This indicates higher blood Epo availability in CMS patients and continuous nocturnal erythropoietic stimulus. Additionally, morning Epo/sEpoR and mean sleep-time SpO2 are independent main predictors of Hct. These findings support the role of the Epo system in the development of excessive erythrocytosis in CMS. Excessive erythrocytosis (EE) is the main sign of Chronic Mountain Sickness (CMS), a highly prevalent syndrome in Andean highlanders. Low pulse O2 saturation (SpO2) during sleep and serum androgens have been suggested to contribute to EE in CMS patients. However, whether these factors have a significant impact on the erythropoietin (Epo) system leading to EE is still unclear. We have recently shown that morning soluble Epo receptor (sEpoR), an endogenous Epo antagonist, is decreased in CMS patients suggesting increased Epo availability (increased Epo/sEpoR). The present study aimed to characterize the nocturnal concentration profile of sEpoR and Epo and their relationship with SpO2, Hct, and serum testosterone in healthy highlanders (HH) and CMS patients. Epo and sEpoR concentrations were evaluated every 4 h (6 PM to 6 AM) and nighttime SpO2 was continuously monitored (10 PM to 6 AM) in 39 male participants (CMS, n = 23; HH, n = 16) aged 21-65 yr from Cerro de Pasco, Peru (4,340 m). CMS patients showed higher serum Epo concentrations throughout the night and lower sEpoR from 10 PM to 6 AM. Consequently, Epo/sEpoR was significantly higher in the CMS group at every time point. Mean sleep-time SpO2 was lower in CMS patients compared with HH, while the percentage of sleep time spent with SpO2 < 80% was higher. Multiple-regression analysis showed mean sleep-time SpO2 and Epo/sEpoR as significant predictors of hematocrit corrected for potential confounders (age, body mass index, and testosterone). Testosterone levels were associated neither with Hct nor with erythropoietic factors. In conclusion, our results show sustained erythropoietic stimulus driven by the Epo system in CMS patients, further enhanced by a continuous exposure to accentuated nocturnal hypoxemia.
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Affiliation(s)
- Francisco C Villafuerte
- Laboratorio de Fisiología Comparada, Departamento de Ciencias Biológicas y Fisiológicas, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Noemí Corante
- Laboratorio de Fisiología Comparada, Departamento de Ciencias Biológicas y Fisiológicas, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Cecilia Anza-Ramírez
- Laboratorio de Fisiología Comparada, Departamento de Ciencias Biológicas y Fisiológicas, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Rómulo Figueroa-Mujíca
- Laboratorio de Fisiología Comparada, Departamento de Ciencias Biológicas y Fisiológicas, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Gustavo Vizcardo-Galindo
- Laboratorio de Fisiología Comparada, Departamento de Ciencias Biológicas y Fisiológicas, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Andy Mercado
- Laboratorio de Fisiología Comparada, Departamento de Ciencias Biológicas y Fisiológicas, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - José Luis Macarlupú
- Laboratorio de Fisiología Comparada, Departamento de Ciencias Biológicas y Fisiológicas, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Fabiola León-Velarde
- Laboratorio de Fisiología Comparada, Departamento de Ciencias Biológicas y Fisiológicas, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
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Sightings, edited by Erik R. Swenson and Peter Bärtsch. High Alt Med Biol 2016. [DOI: 10.1089/ham.2016.29009.stg] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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