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Zhou S, Yan J, Song K, Ge RL. High-Altitude Hypoxia Induces Excessive Erythrocytosis in Mice via Upregulation of the Intestinal HIF2a/Iron-Metabolism Pathway. Biomedicines 2023; 11:2992. [PMID: 38001992 PMCID: PMC10669251 DOI: 10.3390/biomedicines11112992] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Revised: 11/02/2023] [Accepted: 11/03/2023] [Indexed: 11/26/2023] Open
Abstract
Excessive erythrocytosis (EE) is a preclinical form of chronic mountain sickness (CMS). The dysregulation of iron metabolism in high-altitude hypoxia may induce EE. The intestinal hypoxia-inducible factor 2 alpha (HIF2a) regulates the genes involved in iron metabolism. Considering these findings, we aimed to investigate the function and mechanism of intestinal HIF2α and the iron metabolism pathway in high-altitude EE mice. C57BL/6J mice were randomized into four groups: the low-altitude group, the high-altitude group, the high-altitude + HIF2α inhibitor group, and the high-altitude + vehicle group. In-vitro experiments were performed using the human intestinal cell line HCT116 cultured under hypoxic conditions for 24 h. Results showed that high-altitude hypoxia significantly increased the expression of intestinal HIF2α and iron metabolism-related genes, including Dmt1, Dcytb, Fpn, Tfrc, and Fth in EE mice. Genetic blockade of the intestinal HIF2α-iron metabolism pathway decreased iron availability in HCT116 cells during hypoxia. The HIF2α inhibitor PT2385 suppressed intestinal HIF2α expression, decreased iron hypermetabolism, and reduced excessive erythrocytosis in mice. These data support the hypothesis that exposure to high-altitude hypoxia can lead to iron hypermetabolism by activating intestinal HIF2α transcriptional regulation, and reduced iron availability improves EE by inhibiting intestinal HIF2α signaling.
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Affiliation(s)
- Sisi Zhou
- Research Center for High Altitude Medicine, Qinghai University, Xining 810001, China; (S.Z.); (J.Y.); (K.S.)
- Key Laboratory of High-Altitude Medicine, Ministry of Education, Xining 810001, China
- Key Laboratory of Application and Foundation for High Altitude Medicine Research in Qinghai Province, Xining 810001, China
| | - Jun Yan
- Research Center for High Altitude Medicine, Qinghai University, Xining 810001, China; (S.Z.); (J.Y.); (K.S.)
- Key Laboratory of High-Altitude Medicine, Ministry of Education, Xining 810001, China
- Key Laboratory of Application and Foundation for High Altitude Medicine Research in Qinghai Province, Xining 810001, China
| | - Kang Song
- Research Center for High Altitude Medicine, Qinghai University, Xining 810001, China; (S.Z.); (J.Y.); (K.S.)
- Key Laboratory of High-Altitude Medicine, Ministry of Education, Xining 810001, China
- Key Laboratory of Application and Foundation for High Altitude Medicine Research in Qinghai Province, Xining 810001, China
| | - Ri-Li Ge
- Research Center for High Altitude Medicine, Qinghai University, Xining 810001, China; (S.Z.); (J.Y.); (K.S.)
- Key Laboratory of High-Altitude Medicine, Ministry of Education, Xining 810001, China
- Key Laboratory of Application and Foundation for High Altitude Medicine Research in Qinghai Province, Xining 810001, China
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Alharthi SB, Kilani I, Solaimani HS, Salami AY, Althubaity NA, Alosaimi NM, Alsulaiman AS, Zainy MH, Qureshi MA, Ahmed MM. Comparative Study of Complete Blood Count Between High-Altitude and Sea-Level Residents in West Saudi Arabia. Cureus 2023; 15:e44889. [PMID: 37814743 PMCID: PMC10560399 DOI: 10.7759/cureus.44889] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/07/2023] [Indexed: 10/11/2023] Open
Abstract
The reduction in oxygen partial pressure at high altitudes leads to diminished oxygen saturation in the arteries, stimulating erythropoietin production and erythropoiesis to restore appropriate oxygenation. While many studies have explored acclimatization to high altitude and its effects on complete blood count (CBC) parameters, our research uniquely examined both male and female healthy individuals, emphasizing the novelty of gender-specific observations. We analyzed 1,160 individuals in Taif (Al Hada), east Saudi Arabia, a high-altitude region, and compared them to 1,044 counterparts in Jeddah, at sea level. Our results revealed significant variations in CBC parameters, including white blood count, red blood count, hemoglobin, hematocrit, platelets, neutrophils, lymphocytes, monocytes, eosinophils, and basophils, reflecting the body's hypoxic response. These variations were observed in both genders, with specific differences noted between males and females. For example, NEU (neutrophils), representing the absolute count of a type of white blood cell essential in the immune system's defense, showed significant variations for males. The male results show that the variation in males between the sea level and high altitudes indicated significant p-values for all CBC parameters except NEU between at sea level (Jeddah city), whose p-value was 0.8696, and at high altitude (Taif city, Al Hada). In contrast, MONO (monocytes), another type of white blood cell involved in immune response, and RBC (red blood cells), responsible for oxygen transport, were mentioned but did not show significant variations for females. The full results for females showed significant results (P<0.0001) for BASO, HCT, HGB, MCH, MCHC, MPV, PLT, RDW, and WBC between the sea-level altitude and high altitude for females. Also, EOS and LYM showed significant P-values of 0.0002 and 0.0001, respectively, while MONO, NEU, and RBC indicated no significance between the sea-level altitude and high altitude for females. The p-values of MONO, NEU, and RBC, respectively, were 0.1907, 0.1259, and 0.0677. The results for both genders combined showed significant variations of all CBC parameters (P<0.0001) between the sea-level altitude and high altitude except for MONO, NEU, and RBC, which were not significant for both males and females, with p-values of 0.1589, 0.2911, and 0.0595, respectively. All unhealthy individuals were excluded from the study with any condition that would cause significant changes in CBC parameters and would skew the results, ensuring a focus on physiological adaptations in healthy subjects. By comparing healthy individuals and examining each gender separately, this study contributes valuable insights into high-altitude acclimatization, enhancing our understanding of physiological adaptations and potentially guiding health management in such environments within the normal range.
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Affiliation(s)
- Siraj B Alharthi
- Biological Sciences Department, King Abdulaziz University, Taif, SAU
| | - Ijtihed Kilani
- Science Department, Shorouq Al Mamlakah International School, Taif, SAU
| | | | - Ahmed Y Salami
- Hematology Laboratory, King Fahad Armed Forces Hospital, Jeddah, SAU
| | | | - Naif M Alosaimi
- Immunology Department, Al Hada Armed Forces Hospital, Taif, SAU
| | | | - Mohamed H Zainy
- Biological Sciences Department, King Abdulaziz University, Jeddah, SAU
| | - Muhammad A Qureshi
- Clinical Laboratory Medicine Department, Al Hada Armed Forces Hospital, Taif, SAU
| | - Mohamed M Ahmed
- City for Scientific Research and Technological Applications, Genetic Engineering and Biotechnology Research Institute (GEBRI), Alexandria, EGY
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Vásquez-Velásquez C, Fernandez-Guzman D, Quispe-Vicuña C, Caira-Chuquineyra B, Ccami-Bernal F, Castillo-Gutierrez P, Arredondo-Nontol M, Gonzales GF. Evaluating the Diagnostic Performance of Hemoglobin in the Diagnosis of Iron Deficiency Anemia in High-Altitude Populations: A Scoping Review. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2023; 20:6117. [PMID: 37372704 DOI: 10.3390/ijerph20126117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 02/07/2023] [Accepted: 02/26/2023] [Indexed: 06/29/2023]
Abstract
We evaluated the available literature on the diagnostic performance of hemoglobin (Hb) in the diagnosis of iron deficiency anemia (IDA) in high-altitude populations. We searched PubMed, Web of Science, Scopus, Embase, Medline by Ovid, the Cochrane Library, and LILCAS until 3 May 2022. We included studies that evaluated the diagnostic performance (sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), receiver operating characteristic (ROC) curves, and accuracy) of Hb (with and without an altitude correction factor) compared to any iron deficiency (ID) marker (e.g., ferritin, soluble transferrin receptor (sTFR), transferrin saturation, or total body iron (TBI)) in populations residing at altitudes (≥1000 m above sea level). We identified a total of 14 studies (with 4522 participants). We found disagreement in diagnostic performance test values between the studies, both in those comparing hemoglobin with and in those comparing hemoglobin without a correction factor for altitude. Sensitivity ranged from 7% to 100%, whereas specificity ranged from 30% to 100%. Three studies reported higher accuracy of uncorrected versus altitude-corrected hemoglobin. Similarly, two studies found that not correcting hemoglobin for altitude improved the receiver operating characteristic (ROC) curves for the diagnosis of iron deficiency anemia. Available studies on high-altitude populations suggest that the diagnostic accuracy of Hb is higher when altitude correction is not used. In addition, the high prevalence of anemia in altitude regions could be due to diagnostic misclassification.
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Affiliation(s)
- Cinthya Vásquez-Velásquez
- Laboratorio de Endocrinología y Reproducción, Laboratorios de Investigación y Desarrollo (LID), Departamento de Ciencias Biológicas y Fisiológicas, Facultad de Ciencias y Filosofía Alberto Cazorla Tálleri, Universidad Peruana Cayetano Heredia, Lima 15102, Peru
- Instituto de Investigaciones de la Altura, Universidad Peruana Cayetano Heredia, Lima 15102, Peru
| | | | - Carlos Quispe-Vicuña
- Sociedad Científica San Fernando, Universidad Nacional Mayor de San Marcos, Lima 15081, Peru
| | | | - Fabricio Ccami-Bernal
- Facultad de Medicina, Universidad Nacional de San Agustín de Arequipa, Arequipa 04001, Peru
| | | | | | - Gustavo F Gonzales
- Laboratorio de Endocrinología y Reproducción, Laboratorios de Investigación y Desarrollo (LID), Departamento de Ciencias Biológicas y Fisiológicas, Facultad de Ciencias y Filosofía Alberto Cazorla Tálleri, Universidad Peruana Cayetano Heredia, Lima 15102, Peru
- Instituto de Investigaciones de la Altura, Universidad Peruana Cayetano Heredia, Lima 15102, Peru
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Excessive Erythrocytosis Is Not Associated With Altered Iron Homeostasis in Men From the World's Highest City. Hemasphere 2023; 7:e849. [PMID: 36844184 PMCID: PMC9949838 DOI: 10.1097/hs9.0000000000000849] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Accepted: 01/23/2023] [Indexed: 02/24/2023] Open
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High-Altitude Hypoxia Exposure Induces Iron Overload and Ferroptosis in Adipose Tissue. Antioxidants (Basel) 2022; 11:antiox11122367. [PMID: 36552575 PMCID: PMC9774922 DOI: 10.3390/antiox11122367] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 11/25/2022] [Accepted: 11/27/2022] [Indexed: 12/05/2022] Open
Abstract
High altitude (HA) has become one of the most challenging environments featuring hypobaric hypoxia, which seriously threatens public health, hence its gradual attraction of public attention over the past decade. The purpose of this study is to investigate the effect of HA hypoxia on iron levels, redox state, inflammation, and ferroptosis in adipose tissue. Here, 40 mice were randomly divided into two groups: the sea-level group and HA hypoxia group (altitude of 5000 m, treatment for 4 weeks). Total iron contents, ferrous iron contents, ROS generation, lipid peroxidation, the oxidative enzyme system, proinflammatory factor secretion, and ferroptosis-related biomarkers were examined, respectively. According to the results, HA exposure increases total iron and ferrous iron levels in both WAT and BAT. Meanwhile, ROS release, MDA, 4-HNE elevation, GSH depletion, as well as the decrease in SOD, CAT, and GSH-Px activities further evidenced a phenotype of redox imbalance in adipose tissue during HA exposure. Additionally, the secretion of inflammatory factors was also significantly enhanced in HA mice. Moreover, the remarkably changed expression of ferroptosis-related markers suggested that HA exposure increased ferroptosis sensitivity in adipose tissue. Overall, this study reveals that HA exposure is capable of inducing adipose tissue redox imbalance, inflammatory response, and ferroptosis, driven in part by changes in iron overload, which is expected to provide novel preventive targets for HA-related illness.
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Correnti M, Gammella E, Cairo G, Recalcati S. Iron Mining for Erythropoiesis. Int J Mol Sci 2022; 23:ijms23105341. [PMID: 35628152 PMCID: PMC9140467 DOI: 10.3390/ijms23105341] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Revised: 05/05/2022] [Accepted: 05/09/2022] [Indexed: 01/27/2023] Open
Abstract
Iron is necessary for essential processes in every cell of the body, but the erythropoietic compartment is a privileged iron consumer. In fact, as a necessary component of hemoglobin and myoglobin, iron assures oxygen distribution; therefore, a considerable amount of iron is required daily for hemoglobin synthesis and erythroid cell proliferation. Therefore, a tight link exists between iron metabolism and erythropoiesis. The liver-derived hormone hepcidin, which controls iron homeostasis via its interaction with the iron exporter ferroportin, coordinates erythropoietic activity and iron homeostasis. When erythropoiesis is enhanced, iron availability to the erythron is mainly ensured by inhibiting hepcidin expression, thereby increasing ferroportin-mediated iron export from both duodenal absorptive cells and reticuloendothelial cells that process old and/or damaged red blood cells. Erythroferrone, a factor produced and secreted by erythroid precursors in response to erythropoietin, has been identified and characterized as a suppressor of hepcidin synthesis to allow iron mobilization and facilitate erythropoiesis.
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Ma J, Zhang T, Wang W, Chen Y, Cai W, Zhu B, Xu L, Gao H, Zhang L, Li J, Gao X. Comparative Transcriptome Analyses of Gayal (Bos frontalis), Yak (Bos grunniens), and Cattle (Bos taurus) Reveal the High-Altitude Adaptation. Front Genet 2022; 12:778788. [PMID: 35087567 PMCID: PMC8789257 DOI: 10.3389/fgene.2021.778788] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Accepted: 12/06/2021] [Indexed: 11/13/2022] Open
Abstract
Gayal and yak are well adapted to their local high-altitude environments, yet the transcriptional regulation difference of the plateau environment among them remains obscure. Herein, cross-tissue and cross-species comparative transcriptome analyses were performed for the six hypoxia-sensitive tissues from gayal, yak, and cattle. Gene expression profiles for all single-copy orthologous genes showed tissue-specific expression patterns. By differential expression analysis, we identified 3,020 and 1,995 differentially expressed genes (DEGs) in at least one tissue of gayal vs. cattle and yak vs. cattle, respectively. Notably, we found that the adaptability of the gayal to the alpine canyon environment is highly similar to the yak living in the Qinghai-Tibet Plateau, such as promoting red blood cell development, angiogenesis, reducing blood coagulation, immune system activation, and energy metabolism shifts from fatty acid β-oxidation to glycolysis. By further analyzing the common and unique DEGs in the six tissues, we also found that numerous expressed regulatory genes related to these functions are unique in the gayal and yak, which may play important roles in adapting to the corresponding high-altitude environment. Combined with WGCNA analysis, we found that UQCRC1 and COX5A are the shared differentially expressed hub genes related to the energy supply of myocardial contraction in the heart-related modules of gayal and yak, and CAPS is a shared differential hub gene among the hub genes of the lung-related module, which is related to pulmonary artery smooth muscle contraction. Additionally, EDN3 is the unique differentially expressed hub gene related to the tracheal epithelium and pulmonary vasoconstriction in the lung of gayal. CHRM2 is a unique differentially expressed hub gene that was identified in the heart of yak, which has an important role in the autonomous regulation of the heart. These results provide a basis for further understanding the complex transcriptome expression pattern and the regulatory mechanism of high-altitude domestication of gayal and yak.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Junya Li
- *Correspondence: Junya Li, ; Xue Gao,
| | - Xue Gao
- *Correspondence: Junya Li, ; Xue Gao,
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8
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Patrician A, Dawkins T, Coombs GB, Stacey B, Gasho C, Gibbons T, Howe CA, Tremblay JC, Stone R, Tymko K, Tymko C, Akins JD, Hoiland RL, Vizcardo-Galindo GA, Figueroa-Mujíca R, Villafuerte FC, Bailey DM, Stembridge M, Anholm JD, Tymko MM, Ainslie PN. GLOBAL REACH 2018: Iron infusion at high altitude reduces hypoxic pulmonary vasoconstriction equally in both lowlanders and healthy Andean highlanders. Chest 2021; 161:1022-1035. [PMID: 34508740 DOI: 10.1016/j.chest.2021.08.075] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 08/18/2021] [Accepted: 08/31/2021] [Indexed: 10/20/2022] Open
Abstract
BACKGROUND Increasing iron bioavailability attenuates hypoxic pulmonary vasoconstriction in both lowlanders and Sherpa at high altitude. In contrast, the pulmonary vasculature of Andeans suffering with chronic mountain sickness is resistant to iron administration. While pulmonary vascular remodeling and hypertension are characteristic features of chronic mountain sickness, the impact of iron administration in healthy Andeans has not been investigated. If the interplay between iron status and pulmonary vascular tone in healthy Andeans remains intact, this could provide valuable clinical insight into the role of iron regulation at high altitude. RESEARCH QUESTION Is the pulmonary vasculature in healthy Andeans responsive to iron infusion? STUDY DESIGN AND METHODS In a double-blinded, block-randomized design, 24 healthy high-altitude Andeans and 22 partially acclimatized lowlanders at 4300 m (Cerro de Pasco, Peru), received an i.v. infusion of either iron [iron (III)-hydroxide sucrose; 200mg] or saline. Markers of iron status were collected at baseline and 4 hours after infusion. Echocardiography was performed during room-air breathing (PIO2=∼96 mmHg) and during exaggerated hypoxia (PIO2=∼73 mmHg), at baseline, and at 2 and 4 hours following the infusion. RESULTS Iron infusion reduced pulmonary artery systolic pressure (PASP) by ∼2.5 mmHg in room air (main effect P<0.001), and by ∼7 mmHg during exaggerated hypoxia (main effect P<0.001) in both lowlanders and healthy Andean highlanders. There was no change in PASP following the infusion of saline. Iron metrics were comparable between groups, except for serum ferritin, which was 1.8-fold higher at baseline in the Andeans when compared to lowlanders [95% confidence interval (CI) 74-121 ng/ml vs. 37-70 ng/ml, respectively; P=0.003]. INTERPRETATION The pulmonary vasculature of healthy Andeans and lowlanders remains sensitive to iron infusion and this response seems to differ from the pathological characteristics of chronic mountain sickness.
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Affiliation(s)
- Alexander Patrician
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan, Kelowna, British Columbia, Canada.
| | - Tony Dawkins
- Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, UK
| | - Geoff B Coombs
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan, Kelowna, British Columbia, Canada
| | - Benjamin Stacey
- Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, Glamorgan, UK
| | - Christopher Gasho
- Department of Medicine, Division of Pulmonary and Critical Care, Loma Linda University School of Medicine, Loma Linda, CA, USA
| | - Travis Gibbons
- School of Physical Education, Sport & Exercise Science, University of Otago, Dunedin, New Zealand
| | - Connor A Howe
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan, Kelowna, British Columbia, Canada
| | - Joshua C Tremblay
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan, Kelowna, British Columbia, Canada
| | - Rachel Stone
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan, Kelowna, British Columbia, Canada
| | - Kaitlyn Tymko
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan, Kelowna, British Columbia, Canada
| | - Courtney Tymko
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan, Kelowna, British Columbia, Canada
| | - John D Akins
- Department of Kinesiology, University of Texas, Arlington, TX, USA
| | - Ryan L Hoiland
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan, Kelowna, British Columbia, Canada
| | - Gustavo A Vizcardo-Galindo
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan, Kelowna, British Columbia, Canada; Laboratorio de Fisiología Comparada/Fisiología del Transporte de Oxígeno, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Perú
| | - Rómulo Figueroa-Mujíca
- Laboratorio de Fisiología Comparada/Fisiología del Transporte de Oxígeno, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Perú
| | - Francisco C Villafuerte
- Laboratorio de Fisiología Comparada/Fisiología del Transporte de Oxígeno, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Perú
| | - Damian M Bailey
- Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, Glamorgan, UK
| | - Michael Stembridge
- Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, UK
| | - James D Anholm
- Department of Medicine, Division of Pulmonary and Critical Care, Loma Linda University School of Medicine, Loma Linda, CA, USA
| | - Michael M Tymko
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan, Kelowna, British Columbia, Canada; Neurovascular Health Lab, Faculty of Kinesiology, Sport, & Recreation, University of Alberta, Edmonton, Alberta, Canada
| | - Philip N Ainslie
- Centre for Heart, Lung and Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan, Kelowna, British Columbia, Canada
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Integrative Review of Exercise at Altitude during Pregnancy. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph18179272. [PMID: 34501869 PMCID: PMC8430622 DOI: 10.3390/ijerph18179272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 08/19/2021] [Accepted: 08/29/2021] [Indexed: 11/17/2022]
Abstract
Many competitive and elite athletes continue to train throughout their pregnancies and many visit or live at altitude. The purpose of this integrative review is to synthesize, analyze and critique published studies regarding the safety of serious recreational or elite athletes exercising at altitude while pregnant. Seven databases were searched, and 157 documents were located, which were screened for appropriateness and reduced to seven articles that met the criteria. The studies were analyzed based on maternal and fetal outcomes. Current recommendations for exercising at altitude were based on sedentary individuals who frequently did not have the expected physiological responses based on research on pregnancy and altitude. It is unknown whether competitive and elite athletes would have similar responses to exercise at altitude. More research on exercise at altitude on individuals with a variety of fitness levels is needed.
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Koivisto-Mørk AE, Svendsen IS, Skattebo Ø, Hallén J, Paulsen G. Impact of baseline serum ferritin and supplemental iron on altitude-induced hemoglobin mass response in elite athletes. Scand J Med Sci Sports 2021; 31:1764-1773. [PMID: 33908091 DOI: 10.1111/sms.13982] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2021] [Revised: 03/26/2021] [Accepted: 04/16/2021] [Indexed: 01/05/2023]
Abstract
The present study explored the impact of pre-altitude serum (s)-ferritin and iron supplementation on changes in hemoglobin mass (ΔHbmass) following altitude training. Measures of Hbmass and s-ferritin from 107 altitude sojourns (9-28 days at 1800-2500 m) with world-class endurance athletes (males n = 41, females n = 25) were analyzed together with iron supplementation and self-reported illness. Altitude sojourns with a hypoxic dose [median (range)] of 1169 (912) km·h increased Hbmass (mean ± SD) 36 ± 38 g (3.7 ± 3.7%, p < 0.001) and decreased s-ferritin -11 (190) µg·L-1 (p = 0.001). Iron supplements [27 (191) mg·day-1 ] were used at 45 sojourns (42%), while only 11 sojourns (10%) were commenced with s-ferritin <35 µg/L. Hbmass increased by 4.6 ± 3.7%, 3.4 ± 3.3%, 4.2 ± 4.3%, and 2.9 ± 3.4% with pre-altitude s-ferritin ≤35 µg·L-1 , 36-50 µg·L-1 , 51-100 µg·L-1 , and >100 µg·L-1 , respectively, with no group difference (p = 0.400). Hbmass increased by 4.1 ± 3.9%, 3.0 ± 3.0% and 3.7 ± 4.7% without, ≤50 mg·day-1 or >50 mg·day-1 supplemental iron, respectively (p = 0.399). Linear mixed model analysis revealed no interaction between pre-altitude s-ferritin and iron supplementation on ΔHbmass (p = 0.906). However, each 100 km·h increase in hypoxic dose augmented ΔHbmass by an additional 0.4% (95% CI: 0.1-0.7%; p = 0.012), while each 1 g·kg-1 higher pre-altitude Hbmass reduced ΔHbmass by -1% (-1.6 to -0.5; p < 0.001), and illness lowered ΔHbmass by -5.7% (-8.3 to -3.1%; p < 0.001). In conclusion, pre-altitude s-ferritin or iron supplementation were not related to the altitude-induced increase in Hbmass (3.7%) in world-class endurance athletes with clinically normal iron stores.
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Affiliation(s)
- Anu Elisa Koivisto-Mørk
- Norwegian Olympic Sports Centre, Norwegian Olympic and Paralympic Committee and Confederation of Sports, Oslo, Norway
| | - Ida Siobhan Svendsen
- Norwegian Olympic Sports Centre, Norwegian Olympic and Paralympic Committee and Confederation of Sports, Oslo, Norway
| | - Øyvind Skattebo
- Department of Physical Performance, Norwegian School of Sport Sciences, Oslo, Norway
| | - Jostein Hallén
- Department of Physical Performance, Norwegian School of Sport Sciences, Oslo, Norway
| | - Gøran Paulsen
- Norwegian Olympic Sports Centre, Norwegian Olympic and Paralympic Committee and Confederation of Sports, Oslo, Norway.,Department of Physical Performance, Norwegian School of Sport Sciences, Oslo, Norway
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11
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Willie CK, Patrician A, Hoiland RL, Williams AM, Gasho C, Subedi P, Anholm J, Drane A, Tymko MM, Nowak-Flück D, Plato S, McBride E, Varoli G, Binsted G, Eller LK, Reimer RA, MacLeod DB, Stembridge M, Ainslie PN. Influence of iron manipulation on hypoxic pulmonary vasoconstriction and pulmonary reactivity during ascent and acclimatization to 5050 m. J Physiol 2021; 599:1685-1708. [PMID: 33442904 DOI: 10.1113/jp281114] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Accepted: 12/16/2020] [Indexed: 12/11/2022] Open
Abstract
KEY POINTS Iron acts as a cofactor in the stabilization of the hypoxic-inducible factor family, and plays an influential role in the modulation of hypoxic pulmonary vasoconstriction. It is uncertain whether iron regulation is altered in lowlanders during either (1) ascent to high altitude, or (2) following partial acclimatization, when compared to high-altitude adapted Sherpa. During ascent to 5050 m, the rise in pulmonary artery systolic pressure (PASP) was blunted in Sherpa, compared to lowlanders; however, upon arrival to 5050 m, PASP levels were comparable in both groups, but the reduction in iron bioavailability was more prevalent in lowlanders compared to Sherpa. Following partial acclimatization to 5050 m, there were differential influences of iron status manipulation (via iron infusion or chelation) at rest and during exercise between lowlanders and Sherpa on the pulmonary vasculature. ABSTRACT To examine the adaptational role of iron bioavailability on the pulmonary vascular responses to acute and chronic hypobaric hypoxia, the haematological and cardiopulmonary profile of lowlanders and Sherpa were determined during: (1) a 9-day ascent to 5050 m (20 lowlanders; 12 Sherpa), and (2) following partial acclimatization (11 ± 4 days) to 5050 m (18 lowlanders; 20 Sherpa), where both groups received an i.v. infusion of either iron (iron (iii)-hydroxide sucrose) or an iron chelator (desferrioxamine). During ascent, there were reductions in iron status in both lowlanders and Sherpa; however, Sherpa appeared to demonstrate a more efficient capacity to mobilize stored iron, compared to lowlanders, when expressed as a Δhepcidin per unit change in either body iron or the soluble transferrin receptor index, between 3400-5050 m (P = 0.016 and P = 0.029, respectively). The rise in pulmonary artery systolic pressure (PASP) was blunted in Sherpa, compared to lowlanders during ascent; however, PASP was comparable in both groups upon arrival to 5050 m. Following partial acclimatization, despite Sherpa demonstrating a blunted hypoxic ventilatory response and greater resting hypoxaemia, they had similar hypoxic pulmonary vasoconstriction when compared to lowlanders at rest. Iron-infusion attenuated PASP in both groups at rest (P = 0.005), while chelation did not exaggerate PASP in either group at rest or during exaggerated hypoxaemia ( P I O 2 = 67 mmHg). During exercise at 25% peak wattage, PASP was only consistently elevated in Sherpa, which persisted following both iron infusion or chelation. These findings provide new evidence on the complex interplay of iron regulation on pulmonary vascular regulation during acclimatization and adaptation to high altitude.
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Affiliation(s)
- Christopher K Willie
- Centre for Heart, Lung, & Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan, Kelowna, British Columbia, Canada
| | - Alexander Patrician
- Centre for Heart, Lung, & Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan, Kelowna, British Columbia, Canada
| | - Ryan L Hoiland
- Centre for Heart, Lung, & Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan, Kelowna, British Columbia, Canada.,Department of Anaesthesiology, Pharmacology and Therapeutics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Alexandra M Williams
- Department of Cellular and Physiological Sciences, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Christopher Gasho
- Pulmonary/Critical Care Section, VA Loma Linda Healthcare System and Department of Medicine, Loma Linda University, Loma Linda, CA, USA
| | - Prajan Subedi
- Pulmonary/Critical Care Section, VA Loma Linda Healthcare System and Department of Medicine, Loma Linda University, Loma Linda, CA, USA
| | - James Anholm
- Pulmonary/Critical Care Section, VA Loma Linda Healthcare System and Department of Medicine, Loma Linda University, Loma Linda, CA, USA
| | - Aimee Drane
- Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, UK
| | - Michael M Tymko
- Centre for Heart, Lung, & Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan, Kelowna, British Columbia, Canada.,Neurovascular Health Laboratory, University of Alberta, Edmonton, Alberta, Canada
| | - Daniela Nowak-Flück
- Centre for Heart, Lung, & Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan, Kelowna, British Columbia, Canada
| | - Sawyer Plato
- Centre for Heart, Lung, & Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan, Kelowna, British Columbia, Canada
| | - Emily McBride
- Centre for Heart, Lung, & Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan, Kelowna, British Columbia, Canada
| | - Giovanfrancesco Varoli
- Centre for Heart, Lung, & Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan, Kelowna, British Columbia, Canada
| | - Gordon Binsted
- Centre for Heart, Lung, & Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan, Kelowna, British Columbia, Canada
| | - Lindsay K Eller
- Faculty of Kinesiology and Cumming School of Medicine, University of Calgary, Alberta, Canada
| | - Raylene A Reimer
- Faculty of Kinesiology and Cumming School of Medicine, University of Calgary, Alberta, Canada
| | - David B MacLeod
- Human Pharmacology & Physiology Lab, Department of Anesthesiology, Duke University Medical Center, Durham, NC, USA
| | - Michael Stembridge
- Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, UK
| | - Philip N Ainslie
- Centre for Heart, Lung, & Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan, Kelowna, British Columbia, Canada
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12
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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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