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Islam Z, Adnan M, Noor H, Chaudhary R, Farhan M, Sherani FS, Rizvi A. Physiotypic variations lead to variations within the normal range for red blood cells and haemoglobin levels in a healthy human population: An evaluation using generalised additive modelling and hierarchical structure analysis. Int J Lab Hematol 2024. [PMID: 38924350 DOI: 10.1111/ijlh.14333] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2024] [Accepted: 06/14/2024] [Indexed: 06/28/2024]
Abstract
OBJECTIVES Haematological parameters have been used for a long time for clinical evaluations, however the dynamics of these parameters has not been studied at length, in healthy populations. We aim to understand the dependence of haematological parameters on human physiotypes. DESIGN AND METHODS Using an age and gender restricted healthy human (male) population (n = 100), we attempt to analyse the dynamics of haemoglobin and red blood cells, with reference to age, height and weight of individuals. Using advanced generalised additive modelling and classical hierarchical structural analysis we aim to establish relationships between these parameters and human physiotypes. RESULTS We demonstrate that definitive relationships can be established for number of red blood cells, haemoglobin levels, RDW-CV, RDW-SD and weight, height and age of individuals. CONCLUSION This study provides a proof of principle, that haematological parameters are dependent on physiotypic variation, within the normal ranges in a healthy population. It may also be noted that there is a definitive influence of height, weight and age on normal ranges and stratification by these factors might therefore make reference intervals narrower, in turn, possibly allowing more precise clinical decisions based on the complete blood count (CBC).
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Affiliation(s)
- Zainul Islam
- Department of Kulliyat, Faculty of Unani Medicine, Aligarh Muslim University, Aligarh, Uttar Pradesh, India
| | - Mohd Adnan
- Department of Kulliyat, Faculty of Unani Medicine, Aligarh Muslim University, Aligarh, Uttar Pradesh, India
| | - Huma Noor
- Department of Kulliyat, Faculty of Unani Medicine, Aligarh Muslim University, Aligarh, Uttar Pradesh, India
| | - Rohit Chaudhary
- Department of Wildlife Sciences, College of Forestry, Navsari Agricultural University, Navsari, Gujrat, India
| | - Mohd Farhan
- Department of Basic Sciences, Preparatory Year, King Faisal University, Al-Ahsa, Saudi Arabia
- Department of Chemistry, College of Science, King Faisal University, Al-Ahsa, Saudi Arabia
| | - F S Sherani
- Department of Kulliyat, Faculty of Unani Medicine, Aligarh Muslim University, Aligarh, Uttar Pradesh, India
| | - Asim Rizvi
- Department of Kulliyat, Faculty of Unani Medicine, Aligarh Muslim University, Aligarh, Uttar Pradesh, India
- Department of Biochemistry, Faculty of Life Sciences, Aligarh Muslim University, Aligarh, Uttar Pradesh, India
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Moya EA, Yu JJ, Brown S, Gu W, Lawrence ES, Carlson R, Brandes A, Wegeng W, Amann K, McIntosh SE, Powell FL, Simonson TS. Tibetans exhibit lower hemoglobin concentration and decreased heart response to hypoxia during poikilocapnia at intermediate altitude relative to Han Chinese. Front Physiol 2024; 15:1334874. [PMID: 38784113 PMCID: PMC11112024 DOI: 10.3389/fphys.2024.1334874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Accepted: 04/09/2024] [Indexed: 05/25/2024] Open
Abstract
Background High-altitude populations exhibit distinct cellular, respiratory, and cardiovascular phenotypes, some of which provide adaptive advantages to hypoxic conditions compared to populations with sea-level ancestry. Studies performed in populations with a history of high-altitude residence, such as Tibetans, support the idea that many of these phenotypes may be shaped by genomic features that have been positively selected for throughout generations. We hypothesize that such traits observed in Tibetans at high altitude also occur in Tibetans living at intermediate altitude, even in the absence of severe sustained hypoxia. Methodology We studied individuals of high-altitude ancestry (Tibetans, n = 17 females; n = 12 males) and sea-level ancestry (Han Chinese, n = 6 females; n = 10 males), both who had been living at ∼1300 m (∼4327 ft) for at least 18 months. We measured hemoglobin concentration ([Hb]), hypoxic ventilatory response (HVR), and hypoxic heart rate response (HHRR) with end-tidal CO2 (PetCO2) held constant (isocapnia) or allowed to decrease with hypoxic hyperventilation (poikilocapnia). We also quantified the contribution of CO2 on ventilation and heart rate by calculating the differences of isocapnic versus poikilocapnic hypoxic conditions (Δ V ˙ I /ΔPetCO2 and ΔHR/ΔPetCO2, respectively). Results Male Tibetans had lower [Hb] compared to Han Chinese males (p < 0.05), consistent with reports for individuals from these populations living at high altitude and sea level. Measurements of ventilation (resting ventilation, HVR, and PetCO2) were similar for both groups. Heart rate responses to hypoxia were similar in both groups during isocapnia; however, HHRR in poikilocapnia was reduced in the Tibetan group (p < 0.03), and the heart rate response to CO2 in hypoxia was lower in Tibetans relative to Han Chinese (p < 0.01). Conclusion These results suggest that Tibetans living at intermediate altitude have blunted cardiac responses in the context of hypoxia. Hence, only some of the phenotypes observed in Tibetans living at high altitude are observed in Tibetans living at intermediate altitude. Whereas blunted cardiac responses to hypoxia is revealed at intermediate altitudes, manifestation of other physiological adaptations to high altitude may require exposure to more severe levels of hypoxia.
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Affiliation(s)
- E. A. Moya
- Division of Pulmonary, Critical Care, Sleep Medicine, and Physiology, Department of Medicine, University of California San Diego, La Jolla, CA, United States
| | - J. J. Yu
- Division of Pulmonary, Critical Care, Sleep Medicine, and Physiology, Department of Medicine, University of California San Diego, La Jolla, CA, United States
| | - S. Brown
- Department of Anesthesiology, Loyola University Medical Center, Maywood, IL, United States
| | - W. Gu
- Division of Pulmonary, Critical Care, Sleep Medicine, and Physiology, Department of Medicine, University of California San Diego, La Jolla, CA, United States
| | - E. S. Lawrence
- Division of Pulmonary, Critical Care, Sleep Medicine, and Physiology, Department of Medicine, University of California San Diego, La Jolla, CA, United States
| | - R. Carlson
- School of Medicine, University of Utah, Salt Lake City, UT, United States
| | - A. Brandes
- School of Medicine, University of Utah, Salt Lake City, UT, United States
| | - W. Wegeng
- Division of Pulmonary, Critical Care, Sleep Medicine, and Physiology, Department of Medicine, University of California San Diego, La Jolla, CA, United States
| | - K. Amann
- Department of Emergency Medicine, University of Rochester Medical Center, Rochester, NY, United States
| | - S. E. McIntosh
- Department of Emergency Medicine, University of Utah Health, Salt Lake City, UT, United States
| | - F. L. Powell
- Division of Pulmonary, Critical Care, Sleep Medicine, and Physiology, Department of Medicine, University of California San Diego, La Jolla, CA, United States
| | - T. S. Simonson
- Division of Pulmonary, Critical Care, Sleep Medicine, and Physiology, Department of Medicine, University of California San Diego, La Jolla, CA, United States
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Holmström PK, Harman TS, Kalker A, Steiner B, Hawkins E, Jorgensen KC, Zhu KT, Kunwar AJ, Thakur N, Dhungel S, Sherpa N, Day TA, Schagatay EK, Bigham AW, Brutsaert TD. Differential splenic responses to hyperoxic breathing at high altitude in Sherpa and lowlanders. Exp Physiol 2024; 109:535-548. [PMID: 38180087 PMCID: PMC10988702 DOI: 10.1113/ep091579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Accepted: 12/12/2023] [Indexed: 01/06/2024]
Abstract
The human spleen contracts in response to stress-induced catecholamine secretion, resulting in a temporary rise in haemoglobin concentration ([Hb]). Recent findings highlighted enhanced splenic response to exercise at high altitude in Sherpa, possibly due to a blunted splenic response to hypoxia. To explore the potential blunted splenic contraction in Sherpas at high altitude, we examined changes in spleen volume during hyperoxic breathing, comparing acclimatized Sherpa with acclimatized individuals of lowland ancestry. Our study included 14 non-Sherpa (7 female) residing at altitude for a mean continuous duration of 3 months and 46 Sherpa (24 female) with an average of 4 years altitude exposure. Participants underwent a hyperoxic breathing test at altitude (4300 m; barrometric pressure = ∼430 torr;P O 2 ${P_{{{\mathrm{O}}_{\mathrm{2}}}}}$ = ∼90 torr). Throughout the test, we measured spleen volume using ultrasonography and monitored oxygen saturation (S p O 2 ${S_{{\mathrm{p}}{{\mathrm{O}}_{\mathrm{2}}}}}$ ). During rest, Sherpa exhibited larger spleens (226 ± 70 mL) compared to non-Sherpa (165 ± 34 mL; P < 0.001; effect size (ES) = 0.95, 95% CI: 0.3-1.6). In response to hyperoxia, non-Sherpa demonstrated 22 ± 12% increase in spleen size (35 ± 17 mL, 95% CI: 20.7-48.9; P < 0.001; ES = 1.8, 95% CI: 0.93-2.66), while spleen size remained unchanged in Sherpa (-2 ± 13 mL, 95% CI: -2.4 to 7.3; P = 0.640; ES = 0.18, 95% CI: -0.10 to 0.47). Our findings suggest that Sherpa and non-Sherpas of lowland ancestry exhibit distinct variations in spleen volume during hyperoxia at high altitude, potentially indicating two distinct splenic functions. In Sherpa, this phenomenon may signify a diminished splenic response to altitude-related hypoxia at rest, potentially contributing to enhanced splenic contractions during physical stress. Conversely, non-Sherpa experienced a transient increase in spleen size during hyperoxia, indicating an active tonic contraction, which may influence early altitude acclimatization in lowlanders by raising [Hb].
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Affiliation(s)
- Pontus K. Holmström
- Department of Health SciencesMid‐Sweden UniversityÖstersundSweden
- Department of Exercise ScienceSyracuse UniversitySyracuseNew YorkUSA
| | - Taylor S. Harman
- Department of AnthropologySyracuse UniversitySyracuseNew YorkUSA
| | - Anne Kalker
- Department of AnesthesiologyRadboud Medical CenterNijmegenNetherlands
| | - Bethany Steiner
- Department of Exercise ScienceSyracuse UniversitySyracuseNew YorkUSA
| | - Ella Hawkins
- Department of AnthropologySyracuse UniversitySyracuseNew YorkUSA
| | | | - Kimberly T. Zhu
- Department of AnthropologyUniversity of CaliforniaLos AngelesCaliforniaUSA
| | - Ajaya J. Kunwar
- Kathmandu Center for Genomics and Research LaboratoryGlobal Hospital, GwarkoLalitpurNepal
| | - Nilam Thakur
- Kathmandu Center for Genomics and Research LaboratoryGlobal Hospital, GwarkoLalitpurNepal
| | - Sunil Dhungel
- College of MedicineNepalese Army Institute of Health SciencesKathmanduNepal
| | - Nima Sherpa
- Local collaborator without institutional affiliation
| | - Trevor A. Day
- Department of BiologyFaculty of Science and TechnologyMount Royal UniversityCalgaryABCanada
| | | | - Abigail W. Bigham
- Department of AnthropologyUniversity of CaliforniaLos AngelesCaliforniaUSA
| | - Tom D. Brutsaert
- Department of Exercise ScienceSyracuse UniversitySyracuseNew YorkUSA
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Yuan Z, Zou Y, Liu X, Wang L, Chen C. Longitudinal study on blood and biochemical indexes of Tibetan and Han in high altitude area. Front Public Health 2023; 11:1282051. [PMID: 38035283 PMCID: PMC10685451 DOI: 10.3389/fpubh.2023.1282051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Accepted: 10/30/2023] [Indexed: 12/02/2023] Open
Abstract
Objective This study aims to review the blood routine and biochemical indicators of the plateau population for three consecutive years, and analyze the impact of the plateau on these blood indicators of the Tibetan population and the Han immigrant population. Method These parameters were extracted from the Laboratory Department of Ali District People's Hospital in Tibet from January 2019 to December 2021, including blood routine, liver and kidney function, blood lipids, myocardial enzyme spectrum, and rheumatic factor indicators. Changes in these parameters were analyzed over 3 consecutive years according to inclusion and exclusion criteria. Result A total of 114 Tibetans and 93 Hans participated in the study. These parameters were significantly different between Tibetan and Han populations. Red blood cells (RBC), hemoglobin (HGB), hematocrit (HCT), mean hemoglobin content (MCH), mean corpuscular hemoglobin concentration (MCHC), white blood cells (WBC), lymphocytes (LYMPH) and monocytes (MONO) were significantly higher in Hans than Tibetans (p < 0.05). Biochemically, total bilirubin (TBIL), direct bilirubin (DBIL), albumin (ALB), urea nitrogen (Urea), creatinine (Cr), uric acid (UA), glucose (GLU), triglycerides (TG) and creatine kinase isoenzyme (CKMB) were significantly higher in Hans than Tibetans; aspartate aminotransferase (AST), glutamyl transpeptidase (GGT), alkaline phosphatase (ALP), antistreptolysin (ASO), and C-reactive protein (CRP) were significantly higher in Tibetans than Hans (p < 0.05). There were no obvious continuous upward or downward trend of the parameters for 3 consecutive years. Conclusion In high-altitude areas, Han immigrants have long-term stress changes compared with Tibetans. The main differences are reflected in the blood system, liver and kidney functions, etc., which provide basic data for further research on the health status of plateau populations.
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Affiliation(s)
- ZhiMin Yuan
- Department of Clinical Laboratory, Shaanxi Provincial Cancer Hospital Affiliated to Xi'an Jiaotong University, Xi'an, China
- Department of Clinical Laboratory, Ali District People's Hospital, Tibet Ali, China
| | - YuanWu Zou
- Department of Clinical Laboratory, Tuberculosis Prevent and Care Hospital of Shanxi Province, Xi’an, China
| | - XiaoXing Liu
- Department of Clinical Laboratory, Ali District People's Hospital, Tibet Ali, China
| | - LongHao Wang
- Department of Otolaryngology and Neck Surgery, Shanghai Ninth People’s Hospital, Shanghai Jiaotong University, Shanghai, China
| | - Cheng Chen
- Department of Clinical Laboratory, Ali District People's Hospital, Tibet Ali, China
- Key Laboratory of Shaanxi Province for Craniofacial Precision Medicine Research, College of Stomatology, Xi'an Jiaotong University, Xi'an, China
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Zhang L, Zhang R, Zhang F, Yin X, Liu Y, Guo Y, Sun P. Comparison of Cardiorespiratory Fitness of Chinese Tibetan Adolescents with Their Han Counterparts: A Cross-Sectional Retrospective Study. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:16526. [PMID: 36554405 PMCID: PMC9779579 DOI: 10.3390/ijerph192416526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/29/2022] [Revised: 12/04/2022] [Accepted: 12/07/2022] [Indexed: 06/17/2023]
Abstract
Cardiorespiratory fitness (CRF) is a core element of healthy physical fitness. Foreign attention to CRF in adolescents at different altitudes is high, while less research has been conducted on Chinese adolescents. In order to compare the CRF of Chinese Tibetan adolescents with their Han counterparts born and raised at high altitude and Chinese Han adolescents at sea level. A total of 2748 participants, including Chinese Tibetan adolescents, Chinese Han adolescents born and raised at high altitudes, and Chinese Han adolescents at sea level aged 12-18 years old, were obtained using convenience sampling and random cluster sampling. The method of the 20 m shuttle run test (20 m SRT) test was used to derive VO2max by equation. One-way ANOVA and LSD methods were conducted, and effect sizes were calculated to compare the CRF of the three types of adolescents. Regression analysis was used to analyze the relationship between altitude and VO2max. The VO2max scores of Chinese Tibetan adolescents and Chinese Han adolescents at sea level were higher than Chinese Han adolescents born and raised at high altitudes. For both boys and girls, the VO2max scores of Chinese Tibetan adolescents exceeded Chinese Han adolescents at sea level after the age of 16 years old. Regression analysis showed that altitude was inversely associated with VO2max. The pace of lung growth may distinguish Chinese Tibetan adolescents from Chinese Han adolescents born and raised at high altitudes. The results of the study suggest that we should focus on the changes in CRF in adolescents at different altitudes and should adopt different CRF interventions for adolescents at different altitudes.
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Affiliation(s)
- Li Zhang
- Department of Physical Education, China University of Mining and Technology, Beijing 100083, China
| | - Ruming Zhang
- Department of Physical Education, China University of Mining and Technology, Beijing 100083, China
| | - Feng Zhang
- Key Laboratory of Adolescent Health Assessment and Exercise Intervention of Ministry of Education, East China Normal University, Shanghai 200241, China
- College of Physical Education and Health, East China Normal University, Shanghai 200241, China
| | - Xiaojian Yin
- College of Economics and Management, Shanghai Institute of Technology, Shanghai 201418, China
| | - Yuan Liu
- Key Laboratory of Adolescent Health Assessment and Exercise Intervention of Ministry of Education, East China Normal University, Shanghai 200241, China
- College of Physical Education and Health, East China Normal University, Shanghai 200241, China
| | - Yaru Guo
- Key Laboratory of Adolescent Health Assessment and Exercise Intervention of Ministry of Education, East China Normal University, Shanghai 200241, China
- College of Physical Education and Health, East China Normal University, Shanghai 200241, China
| | - Pengwei Sun
- Key Laboratory of Adolescent Health Assessment and Exercise Intervention of Ministry of Education, East China Normal University, Shanghai 200241, China
- College of Physical Education and Health, East China Normal University, Shanghai 200241, China
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Zhang L, Meng J, Li H, Tang M, Zhou Z, Zhou X, Feng L, Li X, Guo Y, He Y, He W, Huang X. Hippocampal adaptation to high altitude: a neuroanatomic profile of hippocampal subfields in Tibetans and acclimatized Han Chinese residents. Front Neuroanat 2022; 16:999033. [DOI: 10.3389/fnana.2022.999033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Accepted: 10/25/2022] [Indexed: 11/19/2022] Open
Abstract
The hippocampus is highly plastic and vulnerable to hypoxia. However, it is unknown whether and how it adapts to chronic hypobaric hypoxia in humans. With a unique sample of Tibetans and acclimatized Han Chinese individuals residing on the Tibetan plateau, we aimed to build a neuroanatomic profile of the altitude-adapted hippocampus by measuring the volumetric differences in the whole hippocampus and its subfields. High-resolution T1-weighted magnetic resonance imaging was performed in healthy Tibetans (TH, n = 72) and healthy Han Chinese individuals living at an altitude of more than 3,500 m (HH, n = 27). In addition, healthy Han Chinese individuals living on a plain (HP, n = 72) were recruited as a sea-level reference group. Whereas the total hippocampal volume did not show a significant difference across groups when corrected for age, sex, and total intracranial volume, subfield-level differences within the hippocampus were found. Post hoc analyses revealed that Tibetans had larger core hippocampal subfields (bilateral CA3, right CA4, right dentate gyrus); a larger right hippocampus–amygdala transition area; and smaller bilateral presubiculum, right subiculum, and bilateral fimbria, than Han Chinese subjects (HH and/or HP). The hippocampus and all its subfields were found to be slightly and non-significantly smaller in HH subjects than in HP subjects. As a primary explorational study, our data suggested that while the overall hippocampal volume did not change, the core hippocampus of Tibetans may have an effect of adaptation to chronic hypobaric hypoxia. However, this adaptation may have required generations rather than mere decades to accumulate in the population.
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Bai J, Li L, Li Y, Zhang L. Genetic and immune changes in Tibetan high-altitude populations contribute to biological adaptation to hypoxia. Environ Health Prev Med 2022; 27:39. [PMID: 36244759 PMCID: PMC9640738 DOI: 10.1265/ehpm.22-00040] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2022] [Accepted: 08/19/2022] [Indexed: 07/27/2023] Open
Abstract
BACKGROUND Tibetans have lived at very high altitudes for thousands of years, and have a distinctive suite of physiological traits that enable them to tolerate environmental hypoxia. Expanding awareness and knowledge of the differences in hematology, hypoxia-associated genes, immune system of people living at different altitudes and from different ethnic groups may provide evidence for the prevention of mountain sickness. METHOD Ninety-five Han people at mid-altitude, ninety-five Tibetan people at high-altitude and ninety-eight Han people at high-altitude were recruited. Red blood cell parameters, immune cells, the contents of cytokines, hypoxia-associated gene single nucleotide polymorphisms (SNPs) were measured. RESULTS The values of Hematocrit (HCT), Mean cell volume (MCV) and Mean cell hemoglobin (MCH) in red blood cell, immune cell CD19+ B cell number, the levels of cytokines Erb-B2 receptor tyrosine kinase 3 (ErbB3) and Tumor necrosis factor receptor II (TNF-RII) and the levels of hypoxia-associated factors Hypoxia inducible factor-1α (HIF-1α), Hypoxia inducible factor-2α (HIF-2α) and HIF prolyl 4-hydroxylase 2 (PHD2) were decreased, while the frequencies of SNPs in twenty-six Endothelial PAS domain protein 1 (EPAS1) and Egl-9 family hypoxia inducible factor 1 (EGLN1) were increased in Tibetan people at high-altitude compared with that of Han peoples at high-altitude. Furthermore, compared with mid-altitude individuals, high-altitude individuals showed lower blood cell parameters including Hemoglobin concentration (HGB), HCT, MCV and MCH, higher Mean cell hemoglobin concentration (MCHC), lower immune cells including CD19+ B cells, CD4+ T cells and CD4/CD8 ratio, higher immune cells containing CD8+ T cells and CD16/56NK cells, decreased Growth regulated oncogene alpha (GROa), Macrophage inflammatory protein 1 beta (MIP-1b), Interleukin-8 (IL-8), and increased Thrombomodulin, downregulated hypoxia-associated factors including HIF1α, HIF2α and PHD2, and higher frequency of EGLN1 rs2275279. CONCLUSIONS These results indicated that biological adaption to hypoxia at high altitude might have been mediated by changes in immune cells, cytokines, and hypoxia-associated genes during the evolutionary history of Tibetan populations. Furthermore, different responses to high altitude were observed in different ethnic groups, which may provide a useful knowledge to improve the protection of high-altitude populations from mountain sickness.
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Affiliation(s)
- Jun Bai
- Institute of Hematology, Lanzhou University Second Hospital, Lanzhou 730000, China
- Gansu Key Laboratory of Hematology, Lanzhou 730000, China
| | - Lijuan Li
- Institute of Hematology, Lanzhou University Second Hospital, Lanzhou 730000, China
- Gansu Key Laboratory of Hematology, Lanzhou 730000, China
| | - Yanhong Li
- Institute of Hematology, Lanzhou University Second Hospital, Lanzhou 730000, China
- Gansu Key Laboratory of Hematology, Lanzhou 730000, China
| | - Liansheng Zhang
- Institute of Hematology, Lanzhou University Second Hospital, Lanzhou 730000, China
- Gansu Key Laboratory of Hematology, Lanzhou 730000, China
- Dingxi People’s Hospital, Dingxi 730500, China
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Basak N, Norboo T, Mustak MS, Thangaraj K. Heterogeneity in Hematological Parameters of High and Low Altitude Tibetan Populations. J Blood Med 2021; 12:287-298. [PMID: 34040473 PMCID: PMC8139737 DOI: 10.2147/jbm.s294564] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Accepted: 03/16/2021] [Indexed: 12/16/2022] Open
Abstract
Introduction High altitude hypoxia is believed to be experienced at elevations of more than 2500 meters above sea level. Several studies have shed light on the biochemical aspects of high altitude acclimatization, where participants were sojourners to the high altitude from low altitude areas. However, information regarding the difference between the high altitude adapted Tibetans living at high altitude and their counterparts who reside at low altitude are lacking. To understand this, we have measured various hematological parameters in the Tibetan populations, who are residing in both high and low altitudes in India. Methods A total of 168 individuals (79 from high altitude (≥4500 meters) and 89 from low altitude (~850 meters) were recruited for this study. Hematological parameters such as red blood cells (RBC) count, hematocrit (HCT), hemoglobin concentration (Hb), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH) and mean corpuscular hemoglobin concentration (MCHC) were measured from the individuals from high and low altitudes. Serum erythropoietin (EPO) was measured by ELISA. Statistical analyses were performed to compare data from both of the altitudes. Gender-wise comparison of data was reported. Correlation analysis was performed within relevant parameters. Results Highly significant differences (p <0.0001) between high and low altitude Tibetans were detected in RBC count, HCT, Hb, MCHC in both males and females and in MCV in females. In the case of MCHC, however, age and BMI were potential confounders. Nominally significant differences (p <0.05) were detected in MCV and MCH within males. No significant difference in serum EPO level was found between altitude groups, in any gender. No significant correlation was found between serum EPO with Hb as well as serum EPO with HCT. Discussion Our study explores significantly lower RBC count, HCT, Hb, MCH, MCHC and higher MCV in long-term Tibetan residents living at low altitude compared to their high altitude counterparts, which is likely due to the outcome of hematological adaptation to a relatively hyperoxic environment in low altitude areas.
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Affiliation(s)
- Nipa Basak
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India.,Academy of Scientific and Innovative Research, Ghaziabad, India
| | | | | | - Kumarasamy Thangaraj
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India.,Academy of Scientific and Innovative Research, Ghaziabad, India.,DBT-Centre for DNA Fingerprinting and Diagnostics, Hyderabad, India
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Mairbäurl H, Gassmann M, Muckenthaler MU. Geographical ancestry affects normal hemoglobin values in high-altitude residents. J Appl Physiol (1985) 2020; 129:1451-1459. [PMID: 33002380 DOI: 10.1152/japplphysiol.00025.2020] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Increasing the hemoglobin (Hb) concentration is a major mechanism adjusting arterial oxygen content to decreased oxygen partial pressure of inspired air at high altitude. Approximately 5% of the world's population living at altitudes higher than 1,500 m shows this adaptive mechanism. Notably, there is a wide variation in the extent of increase in Hb concentration among different populations. This short review summarizes available information on Hb concentrations of high-altitude residents living at comparable altitudes (3,500-4,500 m) in different regions of the world. An increased Hb concentration is found in all high-altitude populations. The highest mean Hb concentration was found in adult male Andean residents and in Han Chinese living at high altitude, whereas it was lowest in Ethiopians, Tibetans, and Sherpas. A lower plasma volume in Andean high-altitude natives may offer a partial explanation. Indeed, male Andean high-altitude natives have a lower plasma volume than Tibetans and Ethiopians. Moreover, Hb values were lower in adult, nonpregnant females than in males; differences between populations of different ancestry were less pronounced. Various genetic polymorphisms were detected in high-altitude residents thought to favor life in a hypoxic environment, some of which correlate with the relatively low Hb concentration in the Tibetans and Ethiopians, whereas differences in angiotensin-converting enzyme allele distribution may be related to elevated Hb in the Andeans. Taken together, these results indicate different sensitivity of oxygen dependent control of erythropoiesis or plasma volume among populations of different geographical ancestry, offering explanations for differences in the Hb concentration at high altitude.
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Affiliation(s)
- Heimo Mairbäurl
- Departmment of Translational Pneumology, University Hospital Heidelberg, Heidelberg, Germany.,Translational Lung Research Center Heidelberg, Member of the German Center for Lung Research, Heidelberg, Germany
| | - Max Gassmann
- Vetsuisse Faculty, Institute of Veterinary Physiology, University of Zurich, Zurich, Switzerland.,Zurich Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland.,Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Martina U Muckenthaler
- Translational Lung Research Center Heidelberg, Member of the German Center for Lung Research, Heidelberg, Germany.,Departmment of Pediatric Hematology, Oncology and Immunology, University Hospital Heidelberg, Heidelberg, Germany.,Molecular Medicine Partnership Unit, University of Heidelberg, Heidelberg, Germany.,German Centre for Cardiovascular Research, Partner Site Heidelberg/Mannheim, Germany
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Wander K, Su M, Mattison PM, Sum CY, Witt CC, Shenk MK, Blumenfield T, Li H, Mattison SM. High-altitude adaptations mitigate risk for hypertension and diabetes-associated anemia. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2020; 172:156-164. [PMID: 32324912 DOI: 10.1002/ajpa.24032] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Revised: 01/13/2020] [Accepted: 02/19/2020] [Indexed: 12/16/2022]
Abstract
BACKGROUND Human populations native to high altitude exhibit numerous genetic adaptations to hypobaric hypoxia. Among Tibetan plateau peoples, these include increased vasodilation and uncoupling of erythropoiesis from hypoxia. OBJECTIVE/METHODS We tested the hypothesis that these high-altitude adaptations reduce risk for hypertension and diabetes-associated anemia among the Mosuo, a Tibetan-descended population in the mountains of Southwest China that is experiencing rapid economic change and increased chronic disease risk. RESULTS Hypertension was substantially less common among Mosuo than low-altitude Han populations, and models fit to the Han predicted higher probability of hypertension than models fit to the Mosuo. Diabetes was positively associated with anemia among the Han, but not the Mosuo. CONCLUSION The Mosuo have lower risk for hypertension and diabetes-associated anemia than the Han, supporting the hypothesis that high-altitude adaptations affecting blood and circulation intersect with chronic disease processes to lower risk for these outcomes. As chronic diseases continue to grow as global health concerns, it is important to investigate how they may be affected by local genetic adaptations.
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Affiliation(s)
- Katherine Wander
- Department of Anthropology, Binghamton University (SUNY), Binghamton, New York, USA
| | - Mingjie Su
- Ministry of Education Key Laboratory of Contemporary Anthropology, B&R International Joint Laboratory of Eurasian Anthropology, School of Life Science, Fudan University, Shanghai, China
| | - Peter M Mattison
- Department of Anthropology, University of New Mexico, Albuquerque, New Mexico, USA
| | - Chun-Yi Sum
- Department of Anthropology, University of Rochester, Rochester, New York, USA
| | - Christopher C Witt
- Department of Anthropology, University of New Mexico, Albuquerque, New Mexico, USA
| | - Mary K Shenk
- Department of Anthropology, Pennsylvania State University, State College, Pennsylvania, USA
| | - Tami Blumenfield
- Department of Anthropology, University of New Mexico, Albuquerque, New Mexico, USA.,School of Ethnology and Sociology, Yunnan University, Kunming, China
| | - Hui Li
- Ministry of Education Key Laboratory of Contemporary Anthropology, B&R International Joint Laboratory of Eurasian Anthropology, School of Life Science, Fudan University, Shanghai, China
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11
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Schafrank LA, Washabaugh JR, Hoke MK. An examination of breastmilk composition among high altitude Peruvian women. Am J Hum Biol 2020; 32:e23412. [DOI: 10.1002/ajhb.23412] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 02/09/2020] [Accepted: 02/25/2020] [Indexed: 12/25/2022] Open
Affiliation(s)
- Lauren A. Schafrank
- Department of Anthropology University of Pennsylvania Philadelphia Pennsylvania USA
| | | | - Morgan K. Hoke
- Department of Anthropology University of Pennsylvania Philadelphia Pennsylvania USA
- Population Studies Center University of Pennsylvania Philadelphia Pennsylvania USA
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12
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Tan L, Li T, Lei F, Li X, Zhou J, Zhang Y, Ren R, Yang L, Tang X. Longer apnea duration at low altitude in Tibetan and Han highlanders compared with Han lowlanders: A retrospective study. J Sleep Res 2019; 29:e12934. [PMID: 31642144 DOI: 10.1111/jsr.12934] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Revised: 09/25/2019] [Accepted: 09/25/2019] [Indexed: 02/05/2023]
Abstract
Prolonged duration of obstructive apnea (OA) has been observed in highlanders after descending to low altitude. It is proposed that due to adaptation to a hypoxic high-altitude environment, Tibetan highlanders (TH) and Han highlanders (HH) would manifest different OA durations at low altitude as compared to Han lowlanders (HL). Data collection on consecutive obstructive sleep apnea patients (167 TH, 210 HH and 233 HL) was performed over a period of 8 years in Chengdu (altitude 500 m). The analyses were performed with non-matched groups and with body mass index and apnea-hypopnea index-matched groups. Significance rankings for mean duration of OA (s) in non-matched groups and matched groups were TH (27.7; 28.6) = HH (25.7; 26.0) > HL (21.7; 21.3), respectively. For the longest OA duration, the significance rankings across three groups with regard to the percentage of patients having a duration longer than 2 min (%) and mean values (s) were TH (26.9; 82) > HH (10.0; 67) > HL (1.3; 50). In terms of nadir and mean oxygen saturation, significant differences were found between TH and HH or HL. In addition, longest and mean OA duration were positively correlated with blood pressure and heart rate, whereas nadir and mean oxygen saturation were negatively correlated with these measures in both non-matched and matched groups, and the correlation was more robust in TH. These findings raise important clinical questions regarding whether such significant prolongation of OA duration and a more severe hypoxic burden among highlanders, especially in TH, may lead to adverse clinical consequences when at low altitude.
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Affiliation(s)
- Lu Tan
- Sleep Medicine Center, Department of Respiratory and Critical Care Medicine,Translational Neuroscience Center, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
| | - Taomei Li
- Sleep Medicine Center, Department of Respiratory and Critical Care Medicine,Translational Neuroscience Center, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
| | - Fei Lei
- Sleep Medicine Center, Department of Respiratory and Critical Care Medicine,Translational Neuroscience Center, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
| | - Xiao Li
- Sleep Medicine Center, Department of Respiratory and Critical Care Medicine,Translational Neuroscience Center, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
| | - Junying Zhou
- Sleep Medicine Center, Department of Respiratory and Critical Care Medicine,Translational Neuroscience Center, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
| | - Ye Zhang
- Sleep Medicine Center, Department of Respiratory and Critical Care Medicine,Translational Neuroscience Center, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
| | - Rong Ren
- Sleep Medicine Center, Department of Respiratory and Critical Care Medicine,Translational Neuroscience Center, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
| | - Linghui Yang
- Sleep Medicine Center, Department of Respiratory and Critical Care Medicine,Translational Neuroscience Center, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
| | - Xiangdong Tang
- Sleep Medicine Center, Department of Respiratory and Critical Care Medicine,Translational Neuroscience Center, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
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13
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Anqi X, Ruiqi C, Yanming R, Chao Y. Elevated hemoglobin is associated with poor prognosis in Tibetans with poor-grade aneurysmal subarachnoid hemorrhage after clipping: A Retrospective Case-Control Study. Neurochirurgie 2019; 65:365-369. [PMID: 31301387 DOI: 10.1016/j.neuchi.2019.06.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Revised: 03/19/2019] [Accepted: 06/10/2019] [Indexed: 02/05/2023]
Abstract
OBJECTIVES High hemoglobin (HGB) concentration is frequently seen in Tibetans in clinical practice; however, the impact on postsurgical prognosis in patients with poor-grade aneurysmal subarachnoid hemorrhage (aSAH) is not precisely known. Thus, we sought to understand the association between high HGB level and postoperative outcome in Tibetans with poor-grade aSAH. PATIENTS AND METHODS Results of clipping in consecutive Tibetan patients with poor-grade aSAH were analyzed retrospectively for the period January 2012 to January 2017. Based on the upper limit (160g/L) of normal hemoglobin levels, patients were divided to a high (HHC) and a normal (NHC) HGB-level cohort according to the first routine blood result on admission. Propensity score matching was used for baseline matching in the 2 cohorts. Postoperative complications in the 2 groups were compared. Prognosis after ictus, including 6-month neurological functional status and mortality at 30 days and 6 months were also assessed. RESULTS Risk of ischemia, pulmonary embolism and lower-limb deep venous thrombosis (DVT) was higher in HHC than NHC (62.88% vs. 21.64%; P<0.001; 10.30% vs. 1.31%, P<0.005; 24.74% vs. 7.21%, P<0.001, respectively). Hospital stay also differed significantly (15.82±3.86 vs. 10.37±4.80 days; P<0.001). Out of the 194 patients, 150 survived at 6 months. At 6-month neurological functional follow-up, 8 NHC patients had favorable modified Rankin scale (mRS) scores ≤2 at discharge, versus only 1 HHC patient, showing better outcome in NHC than HHC (8.25% vs. 1.03%; P=0.035). In-hospital mortality was significantly greater in HHC than NHC (17.52% vs. 7.22%; P=0.029). 30-day post-ictus mortality was 30.93% in HHC versus 14.43% in NHC (P<0.006). There was also a significant difference in mortality at 6 months post-ictus (47.42% vs. 18.56%; P<0.001). CONCLUSION High HGB level was associated with increased risk of postsurgical cerebral ischemia, pulmonary embolism and lower-limb DVT and poor prognosis in poor-grade aSAH patients. Preoperative hemodilution therapy might be beneficial in reducing operative complications, reducing hospital stay and improving short-term prognosis for neurological functional recovery in aSAH patients with high HGB concentration, but further detailed research is needed.
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Affiliation(s)
- X Anqi
- Department of Neurosurgery, West China Hospital, Sichuan, University, Chengdu 610041, P.R. China.
| | - C Ruiqi
- Department of Neurosurgery, West China Hospital, Sichuan, University, Chengdu 610041, P.R. China.
| | - R Yanming
- Department of Neurosurgery, West China Hospital, Sichuan, University, Chengdu 610041, P.R. China.
| | - Y Chao
- Department of Neurosurgery, West China Hospital, Sichuan, University, Chengdu 610041, P.R. China.
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Gassmann M, Mairbäurl H, Livshits L, Seide S, Hackbusch M, Malczyk M, Kraut S, Gassmann NN, Weissmann N, Muckenthaler MU. The increase in hemoglobin concentration with altitude varies among human populations. Ann N Y Acad Sci 2019; 1450:204-220. [PMID: 31257609 DOI: 10.1111/nyas.14136] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 05/02/2019] [Accepted: 05/16/2019] [Indexed: 02/06/2023]
Abstract
Decreased oxygen availability at high altitude requires physiological adjustments allowing for adequate tissue oxygenation. One such mechanism is a slow increase in the hemoglobin concentration ([Hb]) resulting in elevated [Hb] in high-altitude residents. Diagnosis of anemia at different altitudes requires reference values for [Hb]. Our aim was to establish such values based on published data of residents living at different altitudes by applying meta-analysis and multiple regressions. Results show that [Hb] is increased in all high-altitude residents. However, the magnitude of increase varies among the regions analyzed and among ethnic groups within a region. The highest increase was found in residents of the Andes (1 g/dL/1000 m), but this increment was smaller in all other regions of the world (0.6 g/dL/1000 m). While sufficient data exist for adult males and females showing that sex differences in [Hb] persist with altitude, data for infants, children, and pregnant women are incomplete preventing such analyses. Because WHO reference values were originally based on [Hb] of South American people, we conclude that individual reference values have to be defined for ethnic groups to reliably diagnose anemia and erythrocytosis in high-altitude residents. Future studies need to test their applicability for children of different ages and pregnant women.
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Affiliation(s)
- Max Gassmann
- Institute of Veterinary Physiology, Vetsuisse Faculty and Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland.,Universidad Peruana Cayetano Heredia (UPCH), Lima, Peru
| | - Heimo Mairbäurl
- Translational Lung Research Center Heidelberg (TLRC), the German Center for Lung Research (DZL), Heidelberg, Germany
| | - Leonid Livshits
- Institute of Veterinary Physiology, Vetsuisse Faculty and Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland
| | - Svenja Seide
- Institute of Medical Biometry and Informatics (IMBI), University Hospital Heidelberg, Heidelberg, Germany
| | - Matthes Hackbusch
- Institute of Medical Biometry and Informatics (IMBI), University Hospital Heidelberg, Heidelberg, Germany
| | - Monika Malczyk
- Excellence Cluster Cardiopulmonary System, Justus-Liebig-University Giessen, University of Giessen and Marburg Lung Center, German Center for Lung Research (DZL), Heidelberg, Germany
| | - Simone Kraut
- Excellence Cluster Cardiopulmonary System, Justus-Liebig-University Giessen, University of Giessen and Marburg Lung Center, German Center for Lung Research (DZL), Heidelberg, Germany
| | - Norina N Gassmann
- Institute of Veterinary Physiology, Vetsuisse Faculty and Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland
| | - Norbert Weissmann
- Excellence Cluster Cardiopulmonary System, Justus-Liebig-University Giessen, University of Giessen and Marburg Lung Center, German Center for Lung Research (DZL), Heidelberg, Germany
| | - Martina U Muckenthaler
- Pediatric Hematology, Oncology and Immunology, University Hospital Heidelberg, Molecular Medicine Partnership Unit, University of Heidelberg, Translational Lung Research Center Heidelberg (TLRC), German Center for Lung Research, Heidelberg, Germany
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15
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Ocas-Córdova S, Tapia V, Gonzales GF. Hemoglobin Concentration in Children at Different Altitudes in Peru: Proposal for [Hb] Correction for Altitude to Diagnose Anemia and Polycythemia. High Alt Med Biol 2018; 19:398-403. [PMID: 30251888 PMCID: PMC6909695 DOI: 10.1089/ham.2018.0032] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Accepted: 08/14/2018] [Indexed: 11/12/2022] Open
Abstract
The present study was designed to define the hemoglobin [Hb] increase with altitude in Peruvian children. We suggest the normal range of [Hb] as means ±2 standard deviations (SD), with a value less than - 2 SD as a possible threshold to detect anemia. The prevalence of anemia was calculated. These values were compared to the World Health Organization (WHO) altitude correction parameter and the threshold for anemia of 11 g/dL. Likewise, polycythemia is suggested as [Hb] greater than 2 SD. 2,028,701 children aged 6-59 months were analyzed. The quadratic regression analysis shows that [Hb] is constant between sea level and 999 m. Thereafter, [Hb] increases from 11.32 g/dL (1000 m) up to ∼14.54 g/dL at 4000 m. Applying the threshold for anemia defined by WHO (11 g/dL) results in a prevalence of ∼35% for children living at altitudes <1000 m, and prevalence decreases to ∼4.5% at >4000 m. After [Hb] altitude correction, the prevalence was ∼36% (1000 m) and increases to ∼66% above 4000 m. With our proposed threshold for anemia, the prevalence was ∼15% below 1000 m and ∼5% above 4000 m. For polycythemia ([Hb] >14.5 g/dL), increases were from 1.2% at <1000 m to 39.4% at 4000 m. After [Hb] correction for altitude, the prevalence of polycythemia decreases with altitude. Excessive erythrocytosis defined as [Hb] >19 g/dL shows the highest values at 4000 m, while polycythemia defined as [Hb] greater than 2 SD was reduced at high altitude (HA). In conclusion, using WHO thresholds for anemia and [Hb] correction by altitude most likely overestimates the prevalence of anemia and may underestimate polycythemia in Peruvian children living at HA. Therefore, new threshold values for anemia and polycythemia as mean [Hb] less than 2 SD and greater than 2 SD for populations living at a specific altitude are suggested.
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Affiliation(s)
- Silvana Ocas-Córdova
- Laboratories of Investigation and Development (LID) and Department of Biological and Physiological Sciences, Faculty of Sciences and Philosophy, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Vilma Tapia
- Laboratories of Investigation and Development (LID) and Department of Biological and Physiological Sciences, Faculty of Sciences and Philosophy, Universidad Peruana Cayetano Heredia, Lima, Peru
- Instituto de Investigaciones de Altura, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Gustavo F. Gonzales
- Laboratories of Investigation and Development (LID) and Department of Biological and Physiological Sciences, Faculty of Sciences and Philosophy, Universidad Peruana Cayetano Heredia, Lima, Peru
- Instituto de Investigaciones de Altura, Universidad Peruana Cayetano Heredia, Lima, Peru
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16
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Dika H, Masawe E, Iddi S, Rumanyika R. Plasma hemoglobin concentration among pregnant and non-pregnant women in Mwanza: are we using correct reference values to diagnose anemia in pregnancy? Pan Afr Med J 2018; 30:93. [PMID: 30344877 PMCID: PMC6191253 DOI: 10.11604/pamj.2018.30.93.11954] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2017] [Accepted: 03/14/2018] [Indexed: 11/11/2022] Open
Abstract
Introduction The definition of anemia has attracted considerable interest because several studies have demonstrated that hematologic profile vary with ethnicity in addition to age, sex and altitude. This has led scholars to recommend the use of population specific hematologic reference values in diagnosing blood disorders. However, there is limited information about Tanzanians population specific hemoglobin (Hb) levels which can be used to set cut-off points to define anemia. This study aimed to determine plasma Hb concentrations among healthy Tanzanian women. Methods This cross sectional study was done in Mwanza. Sociodemographic data were collected using questionnaires and plasma Hb concentrations were measured by calorimetric method. Data were analyzed using SPSS. Results A total of 215 (162 pregnant, 53 non-pregnant) women with a mean age of 28.2 ± 6.54 years participated in the study. The mean plasma Hb concentrations were 12.0 ± 1.43 mg/dl and 11.9 ± 1.15 mg/dl for pregnant and non-pregnant women respectively. The Hb levels did not significantly vary between pregnant and non-pregnant women. Using WHO reference values, 45.3% non-pregnant and 26.5% pregnant women were found to be anemic while using the population specific reference, only 1.9% of pregnant and none of non-pregnant women would be classified as anemic. Conclusion Most Tanzanian women who are diagnosed to have anemia during pregnancy, often had developed lower Hb before pregnancy and operational thresholds for diagnosis of anemia observed in this study are lower than WHO recommended references values. We recommend a large scale study to determine hematological profile of Tanzanian.
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Affiliation(s)
- Haruna Dika
- Department of Physiology, Weill Bugando School of Medicine, Catholic University of Health and Allied Sciences, Mwanza, Tanzania
| | - Elizabeth Masawe
- Department of Obstetrics and Gynaecology, Bugando Medical Center, Mwanza, Tanzania.,Archibishop Antony Mayalla School of Nursing, Catholic University of Health and Allied Sciences, Mwanza, Tanzania
| | - Shabani Iddi
- Department of Physiology, Weill Bugando School of Medicine, Catholic University of Health and Allied Sciences, Mwanza, Tanzania
| | - Richard Rumanyika
- Department of Obstetrics and Gynaecology, Bugando Medical Center, Mwanza, Tanzania.,Department of Obstetrics and Gynaecology, Weill Bugando School of Medicine, Catholic University of Health and Allied Sciences, Mwanza, Tanzania
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17
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Burtscher M, Gatterer H, Burtscher J, Mairbäurl H. Extreme Terrestrial Environments: Life in Thermal Stress and Hypoxia. A Narrative Review. Front Physiol 2018; 9:572. [PMID: 29867589 PMCID: PMC5964295 DOI: 10.3389/fphys.2018.00572] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Accepted: 04/30/2018] [Indexed: 12/22/2022] Open
Abstract
Living, working and exercising in extreme terrestrial environments are challenging tasks even for healthy humans of the modern new age. The issue is not just survival in remote environments but rather the achievement of optimal performance in everyday life, occupation, and sports. Various adaptive biological processes can take place to cope with the specific stressors of extreme terrestrial environments like cold, heat, and hypoxia (high altitude). This review provides an overview of the physiological and morphological aspects of adaptive responses in these environmental stressors at the level of organs, tissues, and cells. Furthermore, adjustments existing in native people living in such extreme conditions on the earth as well as acute adaptive responses in newcomers are discussed. These insights into general adaptability of humans are complemented by outcomes of specific acclimatization/acclimation studies adding important information how to cope appropriately with extreme environmental temperatures and hypoxia.
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Affiliation(s)
- Martin Burtscher
- Department of Sport Science, University of Innsbruck, Innsbruck, Austria.,Austrian Society for Alpine and Mountain Medicine, Innsbruck, Austria
| | - Hannes Gatterer
- Department of Sport Science, University of Innsbruck, Innsbruck, Austria.,Institute of Mountain Emergency Medicine, EURAC Research, Bolzano, Italy
| | - Johannes Burtscher
- Laboratory of Molecular and Chemical Biology of Neurodegeneration, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Heimo Mairbäurl
- Medical Clinic VII, Sports Medicine, University Hospital Heidelberg, Heidelberg, Germany.,German Center for Lung Research (DZL/TLRC-H), Heidelberg, Germany
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18
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Zhang JB, Wang L, Chen J, Wang ZY, Cao M, Yie SM, Yang H, Yao XQ, Zeng Y, Yang YC, Xie CB, Zhao TQ. Frequency of Polycythemia and Other Abnormalities in a Tibetan Herdsmen Population Residing in the Kham Area of Sichuan Province, China. Wilderness Environ Med 2018; 29:18-28. [PMID: 29338990 DOI: 10.1016/j.wem.2017.09.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2017] [Revised: 09/19/2017] [Accepted: 09/20/2017] [Indexed: 01/02/2023]
Affiliation(s)
- Jian-Bo Zhang
- Core Laboratory, (Drs Zhang, Chen, Z Wang, Cao, and Yie).
| | - Lin Wang
- Health Management Center, (Drs L Wang and H Yang, Mr Yao, and Ms Zeng)
| | - Jie Chen
- Core Laboratory, (Drs Zhang, Chen, Z Wang, Cao, and Yie)
| | - Zhi-Ying Wang
- Core Laboratory, (Drs Zhang, Chen, Z Wang, Cao, and Yie)
| | - Mei Cao
- Core Laboratory, (Drs Zhang, Chen, Z Wang, Cao, and Yie)
| | - Shang-Mian Yie
- Core Laboratory, (Drs Zhang, Chen, Z Wang, Cao, and Yie)
| | - Hua Yang
- Health Management Center, (Drs L Wang and H Yang, Mr Yao, and Ms Zeng)
| | - Xiao-Qin Yao
- Health Management Center, (Drs L Wang and H Yang, Mr Yao, and Ms Zeng)
| | - Yi Zeng
- Health Management Center, (Drs L Wang and H Yang, Mr Yao, and Ms Zeng)
| | - Yong-Chang Yang
- Clinical Laboratory, (Drs L Wang and H Yang, Mr Yao, and Ms Zeng); Sichuan Provincial People's Hospital, Chengdu, China
| | - Chun-Bao Xie
- Clinical Laboratory, (Drs L Wang and H Yang, Mr Yao, and Ms Zeng); Sichuan Provincial People's Hospital, Chengdu, China
| | - Tai-Qiang Zhao
- Clinical Laboratory, (Drs L Wang and H Yang, Mr Yao, and Ms Zeng); Sichuan Provincial People's Hospital, Chengdu, China
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19
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ROBALINO FLORES XDR, BALLADARES SALTOS AM, GUERENDIAIN MARGNI ME, MORALES MARÍN F. Anthropometric and hematological tests to diagnose nutritional deficiencies in schoolchildren of indigenous communities living in the Andean region of Ecuador. REV NUTR 2017. [DOI: 10.1590/1678-98652017000600005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
ABSTRACT Objective To carry out the anthropometric and biometric-hematological assessments in schoolchildren of the Andean region of Ecuador, in order to improve the diagnosis of nutritional deficiencies. Methods The study has been carried out in the San Juan School (Chimborazo, Ecuador), located at 3,240m of altitude, to 36 children of 5 and 6 years old. Anthropometric analyses (weight, height and body mass index), and hematocrit and hemoglobin concentrations were measured. The hemoglobin measurement was evaluated considering the normal value and the one adapted to the altitude of the area. Results The schoolchildren showed high prevalence of stunting (44%). The values of hematocrit (.=0.001) and hemoglobin (.=0.003) were higher in girls. It should be highlighted that using the normal value of hemoglobin, anemia was not detected. However almost a fifth of the schoolchildren studied were diagnosed with anemia when we applied the correction factors adapted to the altitude. Conclusion The use of correction factors adapted to the altitude is considered essential to do the hematology test in populations that live in high altitude in order to avoid a false diagnosis. Moreover, it is necessary to establish the environmental factors related to the stunted growth of this population of the Andean region.
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20
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Flück D, Morris LE, Niroula S, Tallon CM, Sherpa KT, Stembridge M, Ainslie PN, McManus AM. UBC-Nepal expedition: markedly lower cerebral blood flow in high-altitude Sherpa children compared with children residing at sea level. J Appl Physiol (1985) 2017; 123:1003-1010. [PMID: 28572497 DOI: 10.1152/japplphysiol.00292.2017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Revised: 05/28/2017] [Accepted: 05/30/2017] [Indexed: 12/12/2022] Open
Abstract
Developmental cerebral hemodynamic adaptations to chronic high-altitude exposure, such as in the Sherpa population, are largely unknown. To examine hemodynamic adaptations in the developing human brain, we assessed common carotid (CCA), internal carotid (ICA), and vertebral artery (VA) flow and middle cerebral artery (MCA) velocity in 25 (9.6 ± 1.0 yr old, 129 ± 9 cm, 27 ± 8 kg, 14 girls) Sherpa children (3,800 m, Nepal) and 25 (9.9 ± 0.7 yr old, 143 ± 7 cm, 34 ± 6 kg, 14 girls) age-matched sea level children (344 m, Canada) during supine rest. Resting gas exchange, blood pressure, oxygen saturation and heart rate were assessed. Despite comparable age, height and weight were lower (both P < 0.01) in Sherpa compared with sea level children. Mean arterial pressure, heart rate, and ventilation were similar, whereas oxygen saturation (95 ± 2 vs. 99 ± 1%, P < 0.01) and end-tidal Pco2 (24 ± 3 vs. 36 ± 3 Torr, P < 0.01) were lower in Sherpa children. Global cerebral blood flow was ∼30% lower in Sherpa compared with sea level children. This was reflected in a lower ICA flow (283 ± 108 vs. 333 ± 56 ml/min, P = 0.05), VA flow (78 ± 26 vs. 118 ± 35 ml/min, P < 0.05), and MCA velocity (72 ± 14 vs. 88 ± 14 cm/s, P < 0.01). CCA flow was similar between Sherpa and sea level children (425 ± 92 vs. 441 ± 81 ml/min, P = 0.52). Scaling flow and oxygen uptake for differences in vessel diameter and body size, respectively, led to the same findings. A lower cerebral blood flow in Sherpa children may reflect specific cerebral hemodynamic adaptations to chronic hypoxia.NEW & NOTEWORTHY Cerebral blood flow is lower in Sherpa children compared with children residing at sea level; this may reflect a cerebral hemodynamic pattern, potentially due to adaptation to a hypoxic environment.
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Affiliation(s)
- Daniela Flück
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Science, University of British Columbia, Kelowna, British Columbia, Canada;
| | - Laura E Morris
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Science, University of British Columbia, Kelowna, British Columbia, Canada
| | - Shailesh Niroula
- Institute of Medicine, Tribhuvan University, Kirtipur, Nepal.,Khunde Hospital, Khunde, Nepal; and
| | - Christine M Tallon
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Science, University of British Columbia, Kelowna, British Columbia, Canada
| | | | - Mike Stembridge
- Cardiff School of Sport, Cardiff Metropolitan University, Cardiff, United Kingdom
| | - Philip N Ainslie
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Science, University of British Columbia, Kelowna, British Columbia, Canada
| | - Ali M McManus
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Science, University of British Columbia, Kelowna, British Columbia, Canada
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Abstract
OBJECTIVE Several environmental factors including hypoxia have been reported to contribute to oxidative stress in individuals living in the highlands. However, little is known about the role of oxidized low-density lipoprotein (ox-LDL) among community-dwelling elderly in the Qinghai-Tibet plateau. METHODS The study population comprised 168 community-dwelling elderly subjects aged 60 years or older (male to female ratio, 70:98; mean age, 65.8 years) living in Haiyan County, located 3000 to 3200 m above sea level, 30 km northwest of Xining, Qinghai. The subjects were volunteers who joined a Comprehensive Geriatric Assessment. Plasma ox-LDL was measured in 168 community-dwelling elderly subjects aged 60 years or older (23 Tibetans and 145 Hans) with a monoclonal antibody-based enzyme-linked immunosorbent assay. RESULTS Mean ox-LDL level was higher among Tibetan elderly than Han elderly (Tibetan, 79.0 ± 29.6 U/L; Han, 62.8 ± 23.5 U/L; P = .003). Tibetan ethnicity was significantly associated with ox-LDL levels after adjusting for LDL cholesterol levels. In addition, high ox-LDL levels (≥70 U/L) were significantly associated with a homeostasis model assessment insulin resistance index of at least 1.6 (odds ratio [OR], 2.82; 95% confidence interval [95% CI], 1.11 to 7.15; P = .029) and ankle brachial pressure index of less than 1.0 (OR, 4.85; 95% CI, 1.14 to 10.00; P = .028), after adjusting for age, sex, and ethnicity. CONCLUSIONS Our findings support the hypothesis that ox-LDL levels are higher among Tibetan elderly highlanders compared with those among Han elderly. As ox-LDL levels can affect insulin resistance and arteriosclerosis, further research is needed to determine how oxidative stress influences the health situation among elderly individuals at high altitudes.
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Gilbert-Kawai ET, Milledge JS, Grocott MP, Martin DS. King of the Mountains: Tibetan and Sherpa Physiological Adaptations for Life at High Altitude. Physiology (Bethesda) 2014; 29:388-402. [DOI: 10.1152/physiol.00018.2014] [Citation(s) in RCA: 98] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Anecdotal evidence surrounding Tibetans' and Sherpas' exceptional tolerance to hypobaric hypoxia has been recorded since the beginning of high-altitude exploration. These populations have successfully lived and reproduced at high altitude for hundreds of generations with hypoxia as a constant evolutionary pressure. Consequently, they are likely to have undergone natural selection toward a genotype (and phenotype) tending to offer beneficial adaptation to sustained hypoxia. With the advent of translational human hypoxic research, in which genotype/phenotype studies of healthy individuals at high altitude may be of benefit to hypoxemic critically ill patients in a hospital setting, high-altitude natives may provide a valuable and intriguing model. The aim of this review is to provide a comprehensive summary of the scientific literature encompassing Tibetan and Sherpa physiological adaptations to a high-altitude residence. The review demonstrates the extent to which evolutionary pressure has refined the physiology of this high-altitude population. Furthermore, although many physiological differences between highlanders and lowlanders have been found, it also suggests many more potential avenues of investigation.
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Affiliation(s)
- Edward T. Gilbert-Kawai
- University College London Centre for Altitude Space and Extreme Environment Medicine, UCLH NIHR Biomedical Research Centre, Institute of Sport and Exercise Health, London, United Kingdom
- University College London Division of Surgery and Interventional Science, Royal Free Hospital, London, United Kingdom
- University College Hospital London NIHR Biomedical Research Centre, London, United Kingdom
| | - James S. Milledge
- University College London Centre for Altitude Space and Extreme Environment Medicine, UCLH NIHR Biomedical Research Centre, Institute of Sport and Exercise Health, London, United Kingdom
| | - Michael P.W. Grocott
- University College London Centre for Altitude Space and Extreme Environment Medicine, UCLH NIHR Biomedical Research Centre, Institute of Sport and Exercise Health, London, United Kingdom
- University College Hospital London NIHR Biomedical Research Centre, London, United Kingdom
- Integrative Physiology and Critical Illness Group, Clinical and Experimental Sciences, University of Southampton, Southampton, United Kingdom
- Anaesthesia and Critical Care Research Unit, University Hospital Southampton NHS Foundation Trust, Southampton, United Kingdom; and
- Southampton NIHR Respiratory Biomedical Research Unit, Southampton, United Kingdom
| | - Daniel S. Martin
- University College London Centre for Altitude Space and Extreme Environment Medicine, UCLH NIHR Biomedical Research Centre, Institute of Sport and Exercise Health, London, United Kingdom
- University College London Division of Surgery and Interventional Science, Royal Free Hospital, London, United Kingdom
- University College Hospital London NIHR Biomedical Research Centre, London, United Kingdom
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Bianba, Berntsen S, Andersen LB, Stigum H, Ouzhuluobu, Nafstad P, Wu T, Bjertness E. Exercise capacity and selected physiological factors by ancestry and residential altitude: cross-sectional studies of 9-10-year-old children in Tibet. High Alt Med Biol 2014; 15:162-9. [PMID: 24836751 DOI: 10.1089/ham.2013.1084] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
AIM Several physiological compensatory mechanisms have enabled Tibetans to live and work at high altitude, including increased ventilation and pulmonary diffusion capacity, both of which serve to increase oxygen transport in the blood. The aim of the present study was to compare exercise capacity (maximal power output) and selected physiological factors (arterial oxygen saturation and heart rate at rest and during maximal exercise, resting hemoglobin concentration, and forced vital capacity) in groups of native Tibetan children living at different residential altitudes (3700 vs. 4300 m above sea level) and across ancestry (native Tibetan vs. Han Chinese children living at the same altitude of 3700 m). METHODS A total of 430 9-10-year-old native Tibetan children from Tingri (4300 m) and 406 native Tibetan- and 406 Han Chinese immigrants (77% lowland-born and 33% highland-born) from Lhasa (3700 m) participated in two cross-sectional studies. The maximal power output (W max) was assessed using an ergometer cycle. RESULTS Lhasa Tibetan children had a 20% higher maximal power output (watts/kg) than Tingri Tibetan and 4% higher than Lhasa Han Chinese. Maximal heart rate, arterial oxygen saturation at rest, lung volume, and arterial oxygen saturation were significantly associated with exercise capacity at a given altitude, but could not fully account for the differences in exercise capacity observed between ancestry groups or altitudes. CONCLUSIONS The superior exercise capacity in native Tibetans vs. Han Chinese may reflect a better adaptation to life at high altitude. Tibetans at the lower residential altitude of 3700 m demonstrated a better exercise capacity than residents at a higher altitude of 4300 m when measured at their respective residential altitudes. Such altitude- or ancestry-related difference could not be fully attributed to the physiological factors measured.
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Affiliation(s)
- Bianba
- 1 Research Center for High Altitude Medicine, Tibet University Medical College , Lhasa, Tibet, China
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24
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Hu Y, Sun Q, Li Z, Chen J, Shen C, Song Y, Zhong Q. High basal level of autophagy in high-altitude residents attenuates myocardial ischemia-reperfusion injury. J Thorac Cardiovasc Surg 2014; 148:1674-80. [PMID: 24755328 DOI: 10.1016/j.jtcvs.2014.03.038] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Revised: 03/19/2014] [Accepted: 03/21/2014] [Indexed: 10/25/2022]
Abstract
OBJECTIVE Hypoxia can induce autophagy, which plays an important role in cardioprotection. The present study tested the hypothesis that patients with congenital heart disease living at a high altitude could resist ischemia-reperfusion injury better than those at a low altitude, through elevated basal autophagy by chronic hypoxia. METHODS Twelve Tibetan patients residing at a high altitude of >3000 m and 12 Han patients residing at a low altitude of <500 m with simple atrial or ventricular septal defects were prospectively recruited. All patients underwent cardiopulmonary bypass, maintaining a flow rate of approximately 2.4 to 2.8 L/min/m2 and mean arterial pressure of ≥40 to 60 mm Hg. Myocardial ischemia-reperfusion injury between the 2 groups was compared using cardiac troponin I, brain natriuretic peptide, hematoxylin eosin staining, and the terminal deoxynucleotidyl transferase dUTP nick end labeling test. Autophagy-related proteins microtubule-associated protein 1 light chain 3 II (LC3II), Beclin1, and lysosomal-associated membrane protein 2 (LAMP2) and their upstream protein BCL2/adenovirus E1B 19-kDa protein-interacting protein 3 (Bnip3) were evaluated with Western blotting. RESULTS The maximal cardiac troponin I concentration and increasing x-fold of brain natriuretic peptide in the high-altitude group were obviously lower than those in the low-altitude group (3.10±0.77 vs 7.10±2.28 ng/mL and 2.51±0.94 vs 14.66±6.83, respectively). The preoperative and postoperative levels of LC3II, LAMP2, and upstream Bnip3 in the high-altitude group were obviously greater. No difference was found in the Beclin1 level between the 2 groups at baseline or ischemia-reperfusion. CONCLUSIONS Patients living at a high altitude with congenital heart disease resisted ischemia-reperfusion injury during cardiac surgery better than those at a low altitude, possibly through elevated basal autophagy induced by chronic hypoxia.
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Affiliation(s)
- Yijie Hu
- Department of Cardiovascular Surgery, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing, China
| | - Qi Sun
- Department of Cardiovascular Surgery, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing, China
| | - Zhiping Li
- Department of Cardiovascular Surgery, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing, China
| | - Jianming Chen
- Department of Cardiovascular Surgery, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing, China
| | - Cheng Shen
- Department of Cardiovascular Surgery, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing, China
| | - Yi Song
- Department of Cardiovascular Surgery, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing, China
| | - Qianjin Zhong
- Department of Cardiovascular Surgery, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing, China.
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Petousi N, Robbins PA. Human adaptation to the hypoxia of high altitude: the Tibetan paradigm from the pregenomic to the postgenomic era. J Appl Physiol (1985) 2013; 116:875-84. [PMID: 24201705 PMCID: PMC3972749 DOI: 10.1152/japplphysiol.00605.2013] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
The Tibetan Plateau is one of the highest regions on Earth. Tibetan highlanders are adapted to life and reproduction in a hypoxic environment and possess a suite of distinctive physiological traits. Recent studies have identified genomic loci that have undergone natural selection in Tibetans. Two of these loci, EGLN1 and EPAS1, encode major components of the hypoxia-inducible factor transcriptional system, which has a central role in oxygen sensing and coordinating an organism's response to hypoxia, as evidenced by studies in humans and mice. An association between genetic variants within these genes and hemoglobin concentration in Tibetans at high altitude was demonstrated in some of the studies (8, 80, 96). Nevertheless, the functional variants within these genes and the underlying mechanisms of action are still not known. Furthermore, there are a number of other possible phenotypic traits, besides hemoglobin concentration, upon which natural selection may have acted. Integration of studies at the genomic level with functional molecular studies and studies in systems physiology has the potential to provide further understanding of human evolution in response to high-altitude hypoxia. The Tibetan paradigm provides further insight on the role of the hypoxia-inducible factor system in humans in relation to oxygen homeostasis.
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Affiliation(s)
- Nayia Petousi
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
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26
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Petousi N, Croft QPP, Cavalleri GL, Cheng HY, Formenti F, Ishida K, Lunn D, McCormack M, Shianna KV, Talbot NP, Ratcliffe PJ, Robbins PA. Tibetans living at sea level have a hyporesponsive hypoxia-inducible factor system and blunted physiological responses to hypoxia. J Appl Physiol (1985) 2013; 116:893-904. [PMID: 24030663 PMCID: PMC3972739 DOI: 10.1152/japplphysiol.00535.2013] [Citation(s) in RCA: 81] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Tibetan natives have lived on the Tibetan plateau (altitude ∼4,000 m) for at least 25,000 years, and as such they are adapted to life and reproduction in a hypoxic environment. Recent studies have identified two genetic loci, EGLN1 and EPAS1, that have undergone natural selection in Tibetans, and further demonstrated an association of EGLN1/EPAS1 genotype with hemoglobin concentration. Both genes encode major components of the hypoxia-inducible factor (HIF) transcriptional pathway, which coordinates an organism's response to hypoxia. Patients living at sea level with genetic disease of the HIF pathway have characteristic phenotypes at both the integrative-physiology and cellular level. We sought to test the hypothesis that natural selection to hypoxia within Tibetans results in related phenotypic differences. We compared Tibetans living at sea level with Han Chinese, who are Tibetans' most closely related major ethnic group. We found that Tibetans had a lower hemoglobin concentration, a higher pulmonary ventilation relative to metabolism, and blunted pulmonary vascular responses to both acute (minutes) and sustained (8 h) hypoxia. At the cellular level, the relative expression and hypoxic induction of HIF-regulated genes were significantly lower in peripheral blood lymphocytes from Tibetans compared with Han Chinese. Within the Tibetans, we found a significant correlation between both EPAS1 and EGLN1 genotype and the induction of erythropoietin by hypoxia. In conclusion, this study provides further evidence that Tibetans respond less vigorously to hypoxic challenge. This is evident at sea level and, at least in part, appears to arise from a hyporesponsive HIF transcriptional system.
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Affiliation(s)
- Nayia Petousi
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
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27
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Weitz CA, Liu JC, He X, Chin CT, Garruto RM. Responses of Han Migrants Compared to Tibetans at High Altitude. Am J Hum Biol 2013; 25:169-78. [DOI: 10.1002/ajhb.22368] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2012] [Accepted: 11/26/2012] [Indexed: 11/08/2022] Open
Affiliation(s)
- Charles A. Weitz
- Department of Anthropology; Temple University; Philadelphia; Pennsylvania; 19122
| | - Ji-Chuan Liu
- Beijing Medical University, Maternal and Children's Hospital; Beijing; People's Republic of China
| | - Xing He
- Department of Maternal and Child Health; Qinghai Bureau of Public Health; Xining; People's Republic of China
| | - Chen-Ting Chin
- Beijing Medical University, Maternal and Children's Hospital; Beijing; People's Republic of China
| | - Ralph M. Garruto
- Department of Anthropology; Binghamton University, State University of New York; Binghamton; New York; 13902
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28
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Beall CM. Human adaptability studies at high altitude: Research designs and major concepts during fifty years of discovery. Am J Hum Biol 2013; 25:141-7. [DOI: 10.1002/ajhb.22355] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2012] [Accepted: 11/19/2012] [Indexed: 11/08/2022] Open
Affiliation(s)
- Cynthia M. Beall
- Department of Anthropology; Case Western Reserve University; Cleveland; Ohio; 44106-7125
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29
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Tufts DM, Revsbech IG, Cheviron ZA, Weber RE, Fago A, Storz JF. Phenotypic plasticity in blood-oxygen transport in highland and lowland deer mice. ACTA ACUST UNITED AC 2012; 216:1167-73. [PMID: 23239893 DOI: 10.1242/jeb.079848] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
In vertebrates living at high altitude, arterial hypoxemia may be ameliorated by reversible changes in the oxygen-carrying capacity of the blood (regulated by erythropoiesis) and/or changes in blood-oxygen affinity (regulated by allosteric effectors of hemoglobin function). These hematological traits often differ between taxa that are native to different elevational zones, but it is often unknown whether the observed physiological differences reflect fixed, genetically based differences or environmentally induced acclimatization responses (phenotypic plasticity). Here, we report measurements of hematological traits related to blood-O2 transport in populations of deer mice (Peromyscus maniculatus) that are native to high- and low-altitude environments. We conducted a common-garden breeding experiment to assess whether altitude-related physiological differences were attributable to developmental plasticity and/or physiological plasticity during adulthood. Under conditions prevailing in their native habitats, high-altitude deer mice from the Rocky Mountains exhibited a number of pronounced hematological differences relative to low-altitude conspecifics from the Great Plains: higher hemoglobin concentrations, higher hematocrits, higher erythrocytic concentrations of 2,3-diphosphoglycerate (an allosteric regulator of hemoglobin-oxygen affinity), lower mean corpuscular hemoglobin concentrations and smaller red blood cells. However, these differences disappeared after 6 weeks of acclimation to normoxia at low altitude. The measured traits were also indistinguishable between the F1 progeny of highland and lowland mice, indicating that there were no persistent differences in phenotype that could be attributed to developmental plasticity. These results indicate that the naturally occurring hematological differences between highland and lowland mice are environmentally induced and are largely attributable to physiological plasticity during adulthood.
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Affiliation(s)
- Danielle M Tufts
- School of Biological Sciences, University of Nebraska, Lincoln, NE 68588, USA.
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Genetic variants in EPAS1 contribute to adaptation to high-altitude hypoxia in Sherpas. PLoS One 2012; 7:e50566. [PMID: 23227185 PMCID: PMC3515610 DOI: 10.1371/journal.pone.0050566] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2012] [Accepted: 10/22/2012] [Indexed: 01/01/2023] Open
Abstract
Sherpas comprise a population of Tibetan ancestry in the Himalayan region that is renowned for its mountaineering prowess. The very small amount of available genetic information for Sherpas is insufficient to explain their physiological ability to adapt to high-altitude hypoxia. Recent genetic evidence has indicated that natural selection on the endothelial PAS domain protein 1 (EPAS1) gene was occurred in the Tibetan population during their occupation in the Tibetan Plateau for millennia. Tibetan-specific variations in EPAS1 may regulate the physiological responses to high-altitude hypoxia via a hypoxia-inducible transcription factor pathway. We examined three significant tag single-nucleotide polymorphisms (SNPs, rs13419896, rs4953354, and rs4953388) in the EPAS1 gene in Sherpas, and compared these variants with Tibetan highlanders on the Tibetan Plateau as well as with non-Sherpa lowlanders. We found that Sherpas and Tibetans on the Tibetan Plateau exhibit similar patterns in three EPAS1 significant tag SNPs, but these patterns are the reverse of those in non-Sherpa lowlanders. The three SNPs were in strong linkage in Sherpas, but in weak linkage in non-Sherpas. Importantly, the haplotype structured by the Sherpa-dominant alleles was present in Sherpas but rarely present in non-Sherpas. Surprisingly, the average level of serum erythropoietin in Sherpas at 3440 m was equal to that in non-Sherpas at 1300 m, indicating a resistant response of erythropoietin to high-altitude hypoxia in Sherpas. These observations strongly suggest that EPAS1 is under selection for adaptation to the high-altitude life of Tibetan populations, including Sherpas. Understanding of the mechanism of hypoxia tolerance in Tibetans is expected to provide lights to the therapeutic solutions of some hypoxia-related human diseases, such as cardiovascular disease and cancer.
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Wang Z, Zhang Y. Predicted structural change in erythropoietin of plateau zokors--adaptation to high altitude. Gene 2012; 501:206-12. [PMID: 22425647 DOI: 10.1016/j.gene.2012.02.045] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2011] [Revised: 02/19/2012] [Accepted: 02/21/2012] [Indexed: 10/28/2022]
Abstract
Erythropoietin (EPO) is a glycoprotein hormone, expressed mainly in fetus liver and adult kidneys. EPO plays an important role in enhancing red blood cell formation in bone marrow under hypoxia. Plateau zokor (Myospalax baileyi), an subterranean burrowing endemic rodent inhabiting areas of 2 800-4 200 m above sea level on Qinghai-Tibet Plateau, is a typical high hypoxia tolerant mammal with high ratio of oxygen utilization in adaptation to the harsh plateau environment. To investigate the possible mechanisms of adaptation of plateau zokor EPO to high altitude, the complete cDNA and amino acid sequences of plateau zokor EPO have been described. Phylogenetic tree of Epo showed the convergence of the Spalax and Myospalax, indicating that, the convergent evolution was driven by similar hypoxic ecological niches. Our results showed that some common sites under positive selection in zokor (116M and 144A) and Spalax (102R, 116M, 144A and 152P) are the important sites for Epo biological activity. This study thus reports a gene level observation which may be involved in adaptation to underground life at high altitude.
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Affiliation(s)
- Zhenlong Wang
- Department of Bioengineering, Zhengzhou University, Zhengzhou, 450001, Hennan, PR China
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32
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Beall CM, Jablonski NG, Steegmann AT. Human Adaptation to Climate: Temperature, Ultraviolet Radiation, and Altitude. Hum Biol 2012. [DOI: 10.1002/9781118108062.ch6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Storz JF, Scott GR, Cheviron ZA. Phenotypic plasticity and genetic adaptation to high-altitude hypoxia in vertebrates. J Exp Biol 2010; 213:4125-36. [PMID: 21112992 PMCID: PMC2992463 DOI: 10.1242/jeb.048181] [Citation(s) in RCA: 274] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/31/2010] [Indexed: 01/08/2023]
Abstract
High-altitude environments provide ideal testing grounds for investigations of mechanism and process in physiological adaptation. In vertebrates, much of our understanding of the acclimatization response to high-altitude hypoxia derives from studies of animal species that are native to lowland environments. Such studies can indicate whether phenotypic plasticity will generally facilitate or impede adaptation to high altitude. Here, we review general mechanisms of physiological acclimatization and genetic adaptation to high-altitude hypoxia in birds and mammals. We evaluate whether the acclimatization response to environmental hypoxia can be regarded generally as a mechanism of adaptive phenotypic plasticity, or whether it might sometimes represent a misdirected response that acts as a hindrance to genetic adaptation. In cases in which the acclimatization response to hypoxia is maladaptive, selection will favor an attenuation of the induced phenotypic change. This can result in a form of cryptic adaptive evolution in which phenotypic similarity between high- and low-altitude populations is attributable to directional selection on genetically based trait variation that offsets environmentally induced changes. The blunted erythropoietic and pulmonary vasoconstriction responses to hypoxia in Tibetan humans and numerous high-altitude birds and mammals provide possible examples of this phenomenon. When lowland animals colonize high-altitude environments, adaptive phenotypic plasticity can mitigate the costs of selection, thereby enhancing prospects for population establishment and persistence. By contrast, maladaptive plasticity has the opposite effect. Thus, insights into the acclimatization response of lowland animals to high-altitude hypoxia can provide a basis for predicting how altitudinal range limits might shift in response to climate change.
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Affiliation(s)
- Jay F Storz
- School of Biological Sciences, University of Nebraska, Lincoln, NE 68588, USA.
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Natural selection on EPAS1 (HIF2alpha) associated with low hemoglobin concentration in Tibetan highlanders. Proc Natl Acad Sci U S A 2010; 107:11459-64. [PMID: 20534544 DOI: 10.1073/pnas.1002443107] [Citation(s) in RCA: 570] [Impact Index Per Article: 40.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
By impairing both function and survival, the severe reduction in oxygen availability associated with high-altitude environments is likely to act as an agent of natural selection. We used genomic and candidate gene approaches to search for evidence of such genetic selection. First, a genome-wide allelic differentiation scan (GWADS) comparing indigenous highlanders of the Tibetan Plateau (3,200-3,500 m) with closely related lowland Han revealed a genome-wide significant divergence across eight SNPs located near EPAS1. This gene encodes the transcription factor HIF2alpha, which stimulates production of red blood cells and thus increases the concentration of hemoglobin in blood. Second, in a separate cohort of Tibetans residing at 4,200 m, we identified 31 EPAS1 SNPs in high linkage disequilibrium that correlated significantly with hemoglobin concentration. The sex-adjusted hemoglobin concentration was, on average, 0.8 g/dL lower in the major allele homozygotes compared with the heterozygotes. These findings were replicated in a third cohort of Tibetans residing at 4,300 m. The alleles associating with lower hemoglobin concentrations were correlated with the signal from the GWADS study and were observed at greatly elevated frequencies in the Tibetan cohorts compared with the Han. High hemoglobin concentrations are a cardinal feature of chronic mountain sickness offering one plausible mechanism for selection. Alternatively, as EPAS1 is pleiotropic in its effects, selection may have operated on some other aspect of the phenotype. Whichever of these explanations is correct, the evidence for genetic selection at the EPAS1 locus from the GWADS study is supported by the replicated studies associating function with the allelic variants.
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35
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Okumiya K, Sakamoto R, Kimura Y, Ishine M, Kosaka Y, Wada T, Wada C, Nakatsuka M, Ishimoto Y, Hirosaki M, Kasahara Y, Konno A, Chen W, Fujisawa M, Otsuka K, Nakashima M, Wang H, Dai Q, Yang A, Qiao H, Gao J, Li Z, Zhang Y, Ge RL, Matsubayashi K. Comprehensive geriatric assessment of elderly highlanders in Qinghai, China II: the association of polycythemia with lifestyle-related diseases among the three ethnicities. Geriatr Gerontol Int 2010; 9:342-51. [PMID: 20002753 DOI: 10.1111/j.1447-0594.2009.00555.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
AIM The objective of this study is to disclose the association of polycythemia with lifestyle-related diseases (hypertension, obesity and glucose intolerance) among the three ethnicities in Qinghai, China. METHODS The subjects were 393 elderly people (247 Han, 97 Tibetan and 49 Mongolian) aged 60 years and more living in Qinghai (3000 m a.s.l.) in China. The associated factors with polycythemia were analyzed in the subjects. Excessive polycythemia was defined as hemoglobin concentration over 20 mg/dL. RESULTS Polycythemia was associated with men, hypoxemia, obesity and high diastolic blood pressure (DBP) in the elderly in Qinghai. Male sex was associated with polycythemia in all ethnicities. Obesity was associated with Han and Tibetan men. Glucose intolerance and activities of daily living were not directly associated with polycythemia after adjustment for sex. There were 7.9% with excessive polycythemia. Independently-associated factors for excessive polycythemia were male sex, body mass index of 25 or more, SpO(2) of less than 85%, DBP of 85 mmHg or more and Han ethnicity (vs Tibetan) by multiple logistic regression. CONCLUSION There was a close association of polycythemia with diastolic hypertension and obesity in lifestyle-related diseases in high-altitude elderly people. Han people had a higher hemoglobin concentration after adjustment of lifestyle-related diseases compared with Tibetan people. The difference of hemoglobin concentration may be due to Tibetans undergoing a much longer period of adaptation than Han people. Further study is needed to disclose the association between the difference of hypoxic adaptation, lifestyle-related diseases and chronic mountain sickness for their prevention.
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Affiliation(s)
- Kiyohito Okumiya
- Research Institute for Humanity and Nature, 457-4 Motoyama, Kamigamo, Kita-ku, Kyoto 603-8047, Japan.
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Sakamoto R, Matsubayashi K, Kimura Y, Ishine M, Kosaka Y, Wada T, Wada C, Nakatsuka M, Ishimoto Y, Hirosaki M, Kasahara Y, Konno A, Chen W, Fujisawa M, Otsuka K, Nakashima M, Wang H, Dai Q, Yang A, Qiao H, Gao J, Li Z, Zhang Y, Ge RL, Okumiya K. Comprehensive geriatric assessment of elderly highlanders in Qinghai, China, III: oxidative stress and aging in Tibetan and Han elderly highlanders. Geriatr Gerontol Int 2010; 9:352-8. [PMID: 20002754 DOI: 10.1111/j.1447-0594.2009.00544.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND Although there are several factors which may contribute to oxidative stress at high altitude, little is known about the association between oxidative stress and aging in the community-dwelling elderly in the Tibetan Plateau. METHODS Reactive oxygen species (ROS) and comprehensive geriatric functions were examined among 235 community-dwelling elderly subjects aged 60 years or more (146 Hans and 89 Tibetans). As a marker of ROS, the levels of reactive oxygen metabolites (ROM) were measured using the d-ROM test. RESULTS The rate of dependence of basic activities of daily living (basic ADL) among Tibetan elderly highlanders was significantly higher than that among Han elderly highlanders. The d-ROM level was higher among the Tibetan elderly than those among the Han elderly (Tibetan 465.6 +/- 97.9 Carr U, Han 415.3 +/- 72.0 Carr U, P = 0.003). The ROM level was higher among women than those among men. Stepwise multiple regression analysis showed that being Tibetan, female, and oxygen saturation were independent predictors of increasing d-ROM level (Tibetan beta, 0.241; female beta, 0.206; oxygen saturation beta, 0.218). The high levels of ROM (d-ROM >500 Carr U) were significantly associated with dependence of basic ADL after adjustment for age, sex and ethnicity (odds ratio = 2.51, P = 0.028). CONCLUSION The findings of this study imply the possibility that ROS is higher among Tibetan elderly highlanders than that of Han, which related to the geriatric items. Further studies are needed to show the impact of oxidative stress on the aging of highlanders.
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Affiliation(s)
- Ryota Sakamoto
- Research Institute for Humanity and Nature, 457-4 Motoyama, Kamigamo, Kita-ku, Kyoto 603-8047, Japan
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Brooks JTS, Elvidge GP, Glenny L, Gleadle JM, Liu C, Ragoussis J, Smith TG, Talbot NP, Winchester L, Maxwell PH, Robbins PA. Variations within oxygen-regulated gene expression in humans. J Appl Physiol (1985) 2008; 106:212-20. [PMID: 19008490 PMCID: PMC2636937 DOI: 10.1152/japplphysiol.90578.2008] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The effects of hypoxia on gene transcription are mainly mediated by a transcription factor complex termed hypoxia-inducible factor (HIF). Genetic manipulation of animals and studies of humans with rare hereditary disease have shown that modifying the HIF pathway affects systems-level physiological responses to hypoxia. It is, however, an open question whether variations in systems-level responses to hypoxia between individuals could arise from variations within the HIF system. This study sought to determine whether variations in the responsiveness of the HIF system at the cellular level could be detected between normal individuals. Peripheral blood lymphocytes (PBL) were isolated on three separate occasions from each of 10 healthy volunteers. After exposure of PBL to eight different oxygen tensions ranging from 20% to 0.1%, the expression levels of four HIF-regulated transcripts involved in different biological pathways were measured. The profile of expression of all four transcripts in PBL was related to oxygen tension in a curvilinear manner. Double logarithmic transformation of these data resulted in a linear relationship that allowed the response to be parameterized through a gradient and intercept. Analysis of variance (ANOVA) on these parameters showed that the level of between-subject variation in the gradients of the responses that was common across all four HIF-regulated transcripts was significant (P = 0.008). We conclude that statistically significant variation within the cellular response to hypoxia can be detected between normal humans. The common nature of the variability across all four HIF-regulated genes suggests that the source of this variation resides within the HIF system itself.
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Weiss KM, Bigham AW. “So mortal and so strange a pang”: A tribute to Paul T. Baker. Evol Anthropol 2007. [DOI: 10.1002/evan.20140] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Beall CM. Detecting natural selection in high-altitude human populations. Respir Physiol Neurobiol 2007; 158:161-71. [PMID: 17644049 DOI: 10.1016/j.resp.2007.05.013] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2007] [Revised: 05/26/2007] [Accepted: 05/29/2007] [Indexed: 11/16/2022]
Abstract
High-altitude natives have distinctive biological characteristics that appear to offset the stress of hypoxia. Evolutionary theory reasons that they reflect genetic adaptations resulting from natural selection on traits with heritable variation. Furthermore, high-altitude natives of the Andean and Tibetan Plateaus differ from one another, perhaps resulting from different evolutionary histories. Three approaches have developed a case for the possibility of population genetic differences: comparing means of classical physiological traits measured in samples of natives and migrants between altitudes, estimating genetic variance using statistical genetics techniques, and comparing features of species with different evolutionary histories. Tibetans have an inferred autosomal dominant major gene for high oxygen saturation that is associated with higher offspring survival, a strong indicator of ongoing natural selection. New approaches use candidate gene and genomic analyses. Conclusive evidence about population genetic differences and associations with phenotypes remains to be discovered.
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Affiliation(s)
- Cynthia M Beall
- Case Western Reserve University, Department of Anthropology, Cleveland, OH 44106-7125, United States.
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Weitz CA, Garruto RM. A Comparative Analysis of Arterial Oxygen Saturation among Tibetans And Han Born And Raised at High Altitude. High Alt Med Biol 2007; 8:13-26. [PMID: 17394413 DOI: 10.1089/ham.2006.1043] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
This study compares resting arterial oxygen saturation as measured by pulse oximetry (Sp(O2)) among 818 Tibetans and 668 Han who were born and raised at altitudes between 3200 and 4300 m in Qinghai Province, Western China. Both Tibetans and Han show an increase in Sp(O2) values between the ages of 5 and 19 yr, and both groups show a decline after the third decade. However, mean, age-adjusted Sp(O2) values at rest do not differ significantly among growing Tibetans and Han aged 5 through 19 yr or among Tibetans and Han aged 20 through 51 yr. Therefore, the results of this study do not support the hypothesis that indigenous groups possess a superior arterial saturation while awake and at rest compared to lowlanders who have been born and raised at high altitude. Differences between adult Tibetan males and females approach statistical significance (females show higher values than males), while differences between adult Han males and females are not statistically significant. A review of the literature indicates that substantial interstudy variation exists in resting Sp(O2) values among Tibetans residing at high altitudes (between 2% and 4%, depending on the age of individuals measured) and may reflect differences in sample size, health of participants, instruments, probe location, and measurement protocols.
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Affiliation(s)
- Charles A Weitz
- Department of Anthropology, Temple University, Philadelphia, Pennsylvania 19122, USA.
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Abstract
Altitude-related illnesses are a family of interrelated pulmonary, cerebral, hematological, and cardiovascular medical conditions associated with the diminished oxygen availability at moderate to high altitudes. The acute forms of these debilitating and potentially fatal conditions, which include acute mountain sickness (AMS), high altitude pulmonary edema (HAPE), and high altitude cerebral edema (HACE), often develop in incompletely acclimatized lowlanders shortly after ascent, whereas, the chronic conditions, such as chronic mountain sickness (CMS) and high altitude pulmonary hypertension (HAPH), usually afflict native or long-term highlanders and may reflect a loss of adaptation. Anecdotal reports of particularly susceptible people or families are frequently cited as evidence that certain individuals have an innate susceptibility (or resistance) to developing these conditions and, in recent decades, there have been a number of studies designed to characterize the physiology of individuals predisposed to these conditions, as well as to identify the specific genetic variants that contribute to this predisposition. This paper reviews the epidemiological evidence for a genetic component to the various forms of altitude-related illness, such as innate susceptibility, familial clustering, and patterns of population susceptibility, as well as the molecular evidence for specific genetic risk factors. While the evidence supports some role for genetic background in the etiology of altitude-related illness, limitations in individual studies and a general lack of corroborating research limit the conclusions that can be drawn about the extent of this contribution and the specific genes or pathways involved. The paper closes with suggestions for future work that could support and expand on previous studies, as well as provide new insights.
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Affiliation(s)
- Jim L Rupert
- School of Human Kinetics, University of British Columbia, Canada.
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Ritchie RF, Palomaki G. Selecting clinically relevant populations for reference intervals. Clin Chem Lab Med 2005; 42:702-9. [PMID: 15327003 DOI: 10.1515/cclm.2004.120] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The selection of individuals to represent a group for any purpose can commit the effort to success or failure from the very outset. The description of this group must reflect what is, in reality, the purpose for which the group is being studied. Considering that reference intervals are designed to assist clinicians during diagnostic triage, criteria must reflect the nature of the subjects entering the system for care. The majority of people seeking care have non-life-threatening, yet troublesome complaints. In other words, persons who are in a reasonable state of health and who are not suffering from significant illness. Therefore the relevant cohort should fit this description, not individuals who lack any clinical or laboratory issues. Our focus is to employ reference intervals to exclude disease and not to define normality. Normality in the eyes of statisticians is quite different from the word as viewed by clinical staff, yet the term is used interchangeably without concern for its ultimate use. As a result medicine today stumbles over this issue at every turn. Scientists and artists do not speak the same language. Compounding this awkward situation has been the conviction that by increasing laboratory precision and accuracy, the utility of laboratory data, reference intervals in particular, will improve clinical understanding. This has, after many years, not proven to be the case. What has become very evident, however, is that unsustainably large sums of money are being devoted to improving laboratory performance. To what end, when we are unable to grasp the significance of what is available now including published reference intervals for common test values? A realistic perspective on the value of prevailing laboratory performance, as illustrated by reference intervals, must be adopted. The obligation of laboratories, its regulators and professional groups is to create a sustainable mechanism to provide clinically usable information, in a timely and affordable manner, to our population and to those legions of less fortunate humans.
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Wu T, Wang X, Wei C, Cheng H, Wang X, Li Y, Zhao H, Young P, Li G, Wang Z. Hemoglobin levels in Qinghai-Tibet: different effects of gender for Tibetans vs. Han. J Appl Physiol (1985) 2005; 98:598-604. [PMID: 15258131 DOI: 10.1152/japplphysiol.01034.2002] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The Tibetan population, long a resident on the Qinghai-Tibetan Plateau, has lower hemoglobin concentrations than Han Chinese migrants, but it is incompletely known how gender affects the hemoglobin concentrations in the two populations at various altitudes. Measurements of hemoglobin concentration were obtained in 5,887 healthy male and female Tibetan and Han residents aged 5–60 yr, at altitudes of 2,664, 3,813, 4,525, and 5,200 m. Multiple regression equations showed the β-coefficients for altitude and for age were higher ( P < 0.05) in Han men than in Tibetan men and in Han women than in Tibetan women. Analysis indicated a significant three-way interaction between altitude, gender, and ethnicity (χ2 = 3.72, P = 0.05). With increasing altitude, men progressively had more hemoglobin than women in the Han, but not the Tibetan, population. Above 2,664 m, this gender-related difference in hemoglobin concentration increased from childhood to young adulthood more in Han than in Tibetans. We suggest that the Han-Tibetan ethnic difference in the effect of altitude on hemoglobin concentration depends to a large extent on gender.
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Affiliation(s)
- Tianyi Wu
- High Altitude Medical Research Institute, Nanchua West Road #344, Xining, Qinghai, 810012, PR China.
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Abstract
Han Chinese of low-altitude descent have been living in Qinghai Province of Western China for at least two millennia. For most of this time they have lived at elevations under 2,500 m. However, during the last four decades an increasing number of Han have moved into high-altitude towns at elevations over 3,000 m, and some above 4,000 m. There are now sufficient numbers of Han descendants who have been born and raised at high altitude to allow a comparison of their morphological and physiological growth patterns with low-altitude Han to detect the effect of hypoxia. The field study reported here was conducted by collaborating Chinese and American researchers over a 6-year period, and included 1,227 Han living at high altitude in Qinghai and at low altitude near Beijing. This study demonstrates that Han born and raised at high altitude are smaller and lighter than those at low altitude-particularly as children and adolescents. Slower growth at high altitude may be a consequence of hypoxia, but it also corresponds to poorer economic conditions in rural Qinghai Province, and thus may reflect nutritional inadequacies. Differences in altitude and/or nutrition do not seem to affect thorax dimensions, since, relative to stature, chest dimensions are similar at both high and low altitudes. Nevertheless, lung volumes are higher among Han at high altitude, possibly reflecting the influence of hypoxia on alveolar growth. The hematological values of Han growing up at 3,200 m are not different from those at low altitude-an unusual finding relative to other low-altitude groups that may reflect population differences in response to hypoxia. At 3,800 m and 4,300 m, however, Han show elevated hemoglobin relative to Han at low altitude.
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Affiliation(s)
- Charles A Weitz
- Department of Anthropology, Temple University, Philadelphia, Pennsylvania 19122, USA.
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