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Azad P, Caldwell AB, Ramachandran S, Spann NJ, Akbari A, Villafuerte FC, Bermudez D, Zhao H, Poulsen O, Zhou D, Bafna V, Subramaniam S, Haddad GG. ARID1B, a molecular suppressor of erythropoiesis, is essential for the prevention of Monge's disease. Exp Mol Med 2022; 54:777-787. [PMID: 35672450 PMCID: PMC9256584 DOI: 10.1038/s12276-022-00769-1] [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: 09/29/2021] [Revised: 01/10/2022] [Accepted: 02/14/2022] [Indexed: 11/09/2022] Open
Abstract
At high altitude Andean region, hypoxia-induced excessive erythrocytosis (EE) is the defining feature of Monge's disease or chronic mountain sickness (CMS). At the same altitude, resides a population that has developed adaptive mechanism(s) to constrain this hypoxic response (non-CMS). In this study, we utilized an in vitro induced pluripotent stem cell model system to study both populations using genomic and molecular approaches. Our whole genome analysis of the two groups identified differential SNPs between the CMS and non-CMS subjects in the ARID1B region. Under hypoxia, the expression levels of ARID1B significantly increased in the non-CMS cells but decreased in the CMS cells. At the molecular level, ARID1B knockdown (KD) in non-CMS cells increased the levels of the transcriptional regulator GATA1 by 3-fold and RBC levels by 100-fold under hypoxia. ARID1B KD in non-CMS cells led to increased proliferation and EPO sensitivity by lowering p53 levels and decreasing apoptosis through GATA1 mediation. Interestingly, under hypoxia ARID1B showed an epigenetic role, altering the chromatin states of erythroid genes. Indeed, combined Real-time PCR and ATAC-Seq results showed that ARID1B modulates the expression of GATA1 and p53 and chromatin accessibility at GATA1/p53 target genes. We conclude that ARID1B is a novel erythroid regulator under hypoxia that controls various aspects of erythropoiesis in high-altitude dwellers.
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Affiliation(s)
- Priti Azad
- Division of Respiratory Medicine, Department of Pediatrics, University of California, San Diego, La Jolla, CA, USA
| | - Andrew B Caldwell
- Department of Bioengineering, University of California, San Diego, La Jolla, CA, USA
| | | | - Nathanael J Spann
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Ali Akbari
- Department of Genetics, Harvard Medical School, Boston, MA, USA.,Broad Institute of MIT and Harvard, Cambridge, MA, USA.,Department of Human Evolutionary Biology, Harvard University, Cambridge, MA, USA
| | - Francisco C Villafuerte
- Laboratorio de Fisiología del Transporte de Oxigeno/Fisiología Comparada, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, 31, Peru
| | - Daniela Bermudez
- Laboratorio de Fisiología del Transporte de Oxigeno/Fisiología Comparada, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, 31, Peru
| | - Helen Zhao
- Division of Respiratory Medicine, Department of Pediatrics, University of California, San Diego, La Jolla, CA, USA
| | - Orit Poulsen
- Division of Respiratory Medicine, Department of Pediatrics, University of California, San Diego, La Jolla, CA, USA
| | - Dan Zhou
- Division of Respiratory Medicine, Department of Pediatrics, University of California, San Diego, La Jolla, CA, USA
| | - Vineet Bafna
- Department of Computer Science and Engineering, University of California, San Diego, La Jolla, CA, USA
| | - Shankar Subramaniam
- Department of Bioengineering, University of California, San Diego, La Jolla, CA, USA.,Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA, USA.,Department of Computer Science and Engineering, University of California, San Diego, La Jolla, CA, USA.,Department of Nanoengineering, University of California, San Diego, La Jolla, CA, USA
| | - Gabriel G Haddad
- Division of Respiratory Medicine, Department of Pediatrics, University of California, San Diego, La Jolla, CA, USA. .,Department of Neurosciences, University of California, San Diego, La Jolla, CA, 92093, USA. .,Rady Children's Hospital, San Diego, CA, 92123, USA.
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Liu H, Tang F, Su J, Ma J, Qin Y, Ji L, Geng H, Wang S, Zhang P, Liu J, Cui S, Ge RL, Li Z. EPAS1 regulates proliferation of erythroblasts in chronic mountain sickness. Blood Cells Mol Dis 2020; 84:102446. [PMID: 32470757 DOI: 10.1016/j.bcmd.2020.102446] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 05/14/2020] [Accepted: 05/15/2020] [Indexed: 01/13/2023]
Abstract
Excessive erythrocytosis (EE) is a characteristic of chronic mountain sickness (CMS). Currently, the pathogenesis of CMS remains unclear. This study was intended to investigate the role of EPAS1 in the proliferation of erythroblasts in CMS. Changes of HIF-1α and EPAS1/HIF-2α in the bone marrow erythroblasts of 21 patients with CMS and 14 control subjects residing at the same altitudes were determined by RT-qPCR and western blotting. We also developed a lentiviral vector, Lv-EPAS1/sh-EPAS1, to over-express/silence EPAS1 in K562 cells. Cells cycle and proliferation were detected by flow cytometry. Transcriptome analyses were carried out on Illumina. CMS patients showed a higher expression of EPAS1/HIF-2α in the bone marrow erythroblasts than those of controls. Variations in EPAS1 expression in CMS patients were positively correlated with RBC levels, and negatively correlated with SaO2. Over-expressing of EPAS1 in K562 cells accelerated the erythroid cells cycle progression and promoted the erythroid cells proliferation-and vice versa. Transcriptome data indicated that proliferation-related DEGs were significantly enriched in EPAS1 overexpression/silencing K562 cells. Our results suggest that EPAS1 might participate in the pathogenesis of EE by regulating the proliferation of erythroblasts.
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Affiliation(s)
- Huihui Liu
- Research Center for High Altitude Medicine, Qinghai University, Xining, China; Qinghai Key Laboratory of Science and Technology for High Altitude Medicine, Xining, China; Qinghai-Utah Joint Research Key Lab for High Altitude Medicine, Xining, China; Department of Rheumatology, Affiliated Hospital of Qinghai University, Xining, China
| | - Feng Tang
- Research Center for High Altitude Medicine, Qinghai University, Xining, China; Qinghai Key Laboratory of Science and Technology for High Altitude Medicine, Xining, China; Qinghai-Utah Joint Research Key Lab for High Altitude Medicine, Xining, China
| | - Juan Su
- Department of Rheumatology, Affiliated Hospital of Qinghai University, Xining, China
| | - Jie Ma
- Department of Hematology, Affiliated Hospital of Qinghai University, Xining, China
| | - Yajing Qin
- Department of Rheumatology, Affiliated Hospital of Qinghai University, Xining, China
| | - Linhua Ji
- Department of Hematology, Affiliated Hospital of Qinghai University, Xining, China
| | - Hui Geng
- Department of Rheumatology, Affiliated Hospital of Qinghai University, Xining, China
| | - Shengyan Wang
- Research Center for High Altitude Medicine, Qinghai University, Xining, China; Qinghai Key Laboratory of Science and Technology for High Altitude Medicine, Xining, China; Qinghai-Utah Joint Research Key Lab for High Altitude Medicine, Xining, China
| | - Peili Zhang
- Research Center for High Altitude Medicine, Qinghai University, Xining, China; Qinghai Key Laboratory of Science and Technology for High Altitude Medicine, Xining, China; Qinghai-Utah Joint Research Key Lab for High Altitude Medicine, Xining, China
| | - Junli Liu
- Research Center for High Altitude Medicine, Qinghai University, Xining, China; Qinghai Key Laboratory of Science and Technology for High Altitude Medicine, Xining, China; Qinghai-Utah Joint Research Key Lab for High Altitude Medicine, Xining, China
| | - Sen Cui
- Department of Hematology, Affiliated Hospital of Qinghai University, Xining, China
| | - Ri-Li Ge
- Research Center for High Altitude Medicine, Qinghai University, Xining, China; Qinghai Key Laboratory of Science and Technology for High Altitude Medicine, Xining, China; Qinghai-Utah Joint Research Key Lab for High Altitude Medicine, Xining, China
| | - Zhanquan Li
- Department of Rheumatology, Affiliated Hospital of Qinghai University, Xining, China.
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Bermudez D, Azad P, Figueroa-Mujíca R, Vizcardo-Galindo G, Corante N, Guerra-Giraldez C, Haddad GG, Villafuerte FC. Increased hypoxic proliferative response and gene expression in erythroid progenitor cells of Andean highlanders with chronic mountain sickness. Am J Physiol Regul Integr Comp Physiol 2020; 318:R49-R56. [PMID: 31617751 PMCID: PMC6985794 DOI: 10.1152/ajpregu.00250.2019] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Revised: 10/09/2019] [Accepted: 10/10/2019] [Indexed: 12/20/2022]
Abstract
Excessive erythrocytosis (EE) is the main sign of chronic mountain sickness (CMS), a maladaptive clinical syndrome prevalent in Andean and other high-altitude populations worldwide. The pathophysiological mechanism of EE is still controversial, as physiological variability of systemic respiratory, cardiovascular, and hormonal responses to chronic hypoxemia complicates the identification of underlying causes. Induced pluripotent stem cells derived from CMS highlanders showed increased expression of genes relevant to the regulation of erythropoiesis, angiogenesis, cardiovascular, and steroid-hormone function that appear to explain the exaggerated erythropoietic response. However, the cellular response to hypoxia in native CMS cells is yet unknown. This study had three related aims: to determine the hypoxic proliferation of native erythroid progenitor burst-forming unit-erythroid (BFU-E) cells derived from CMS and non-CMS peripheral blood mononuclear cells; to examine their sentrin-specific protease 1 (SENP1), GATA-binding factor 1 (GATA1), erythropoietin (EPO), and EPO receptor (EPOR) expression; and to investigate the functional upstream role of SENP1 in native progenitor differentiation into erythroid precursors. Native CMS BFU-E colonies showed increased proliferation under hypoxic conditions compared with non-CMS cells, together with an upregulated expression of SENP1, GATA1, EPOR; and no difference in EPO expression. Knock-down of the SENP1 gene abolished the augmented proliferative response. Thus, we demonstrate that native CMS progenitor cells produce a larger proportion of erythroid precursors under hypoxia and that SENP1 is essential for proliferation. Our findings suggest a significant intrinsic component for developing EE in CMS highlanders at the cellular and gene expression level that could be further enhanced by systemic factors such as alterations in respiratory control, or differential hormonal patterns.
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Affiliation(s)
- Daniela Bermudez
- Laboratorio de Fisiología Comparada, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Priti Azad
- Division of Respiratory Medicine, Department of Pediatrics, University of California, San Diego, La Jolla, California
| | - Rómulo Figueroa-Mujíca
- Laboratorio de Fisiología Comparada, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Gustavo Vizcardo-Galindo
- Laboratorio de Fisiología Comparada, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Noemí Corante
- Laboratorio de Fisiología Comparada, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Cristina Guerra-Giraldez
- Laboratorio de Inflamación Cerebral, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Gabriel G Haddad
- Division of Respiratory Medicine, Department of Pediatrics, University of California, San Diego, La Jolla, California
- Department of Neurosciences, University of California San Diego, La Jolla, California
- Rady Children's Hospital, San Diego, La Jolla, California
| | - Francisco C Villafuerte
- Laboratorio de Fisiología Comparada, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
- Instituto de Investigaciones de la Altura (IIA), Universidad Peruana Cayetano Heredia, Lima, Peru
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High-altitude adaptation in humans: from genomics to integrative physiology. J Mol Med (Berl) 2017; 95:1269-1282. [PMID: 28951950 DOI: 10.1007/s00109-017-1584-7] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Revised: 08/07/2017] [Accepted: 08/20/2017] [Indexed: 12/19/2022]
Abstract
About 1.2 to 33% of high-altitude populations suffer from Monge's disease or chronic mountain sickness (CMS). Number of factors such as age, sex, and population of origin (older, male, Andean) contribute to the percentage reported from a variety of samples. It is estimated that there are around 83 million people who live at altitudes > 2500 m worldwide and are at risk for CMS. In this review, we focus on a human "experiment in nature" in various high-altitude locations in the world-namely, Andean, Tibetan, and Ethiopian populations that have lived under chronic hypoxia conditions for thousands of years. We discuss the adaptive as well as mal-adaptive changes at the genomic and physiological levels. Although different genes seem to be involved in adaptation in the three populations, we can observe convergence at genetic and signaling, as well as physiological levels. What is important is that we and others have shown that lessons learned from the genes mined at high altitude can be helpful in better understanding and treating diseases that occur at sea level. We discuss two such examples: EDNRB and SENP1 and their role in cardiac tolerance and in the polycythemic response, respectively.
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Azad P, Zhao HW, Cabrales PJ, Ronen R, Zhou D, Poulsen O, Appenzeller O, Hsiao YH, Bafna V, Haddad GG. Senp1 drives hypoxia-induced polycythemia via GATA1 and Bcl-xL in subjects with Monge's disease. J Exp Med 2016; 213:2729-2744. [PMID: 27821551 PMCID: PMC5110013 DOI: 10.1084/jem.20151920] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Revised: 06/02/2016] [Accepted: 10/06/2016] [Indexed: 01/17/2023] Open
Abstract
Azad and collaborators propose that Senp1 drives excessive erythropoiesis in high-altitude Andean dwellers suffering from chronic mountain sickness. In this study, because excessive polycythemia is a predominant trait in some high-altitude dwellers (chronic mountain sickness [CMS] or Monge’s disease) but not others living at the same altitude in the Andes, we took advantage of this human experiment of nature and used a combination of induced pluripotent stem cell technology, genomics, and molecular biology in this unique population to understand the molecular basis for hypoxia-induced excessive polycythemia. As compared with sea-level controls and non-CMS subjects who responded to hypoxia by increasing their RBCs modestly or not at all, respectively, CMS cells increased theirs remarkably (up to 60-fold). Although there was a switch from fetal to adult HgbA0 in all populations and a concomitant shift in oxygen binding, we found that CMS cells matured faster and had a higher efficiency and proliferative potential than non-CMS cells. We also established that SENP1 plays a critical role in the differential erythropoietic response of CMS and non-CMS subjects: we can convert the CMS phenotype into that of non-CMS and vice versa by altering SENP1 levels. We also demonstrated that GATA1 is an essential downstream target of SENP1 and that the differential expression and response of GATA1 and Bcl-xL are a key mechanism underlying CMS pathology.
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Affiliation(s)
- Priti Azad
- Division of Respiratory Medicine, Department of Pediatrics, University of California, San Diego, La Jolla, CA 92093
| | - Huiwen W Zhao
- Division of Respiratory Medicine, Department of Pediatrics, University of California, San Diego, La Jolla, CA 92093
| | - Pedro J Cabrales
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093
| | - Roy Ronen
- Bioinformatics and Systems Biology Graduate Program, University of California, San Diego, La Jolla, CA 92093
| | - Dan Zhou
- Division of Respiratory Medicine, Department of Pediatrics, University of California, San Diego, La Jolla, CA 92093
| | - Orit Poulsen
- Division of Respiratory Medicine, Department of Pediatrics, University of California, San Diego, La Jolla, CA 92093
| | - Otto Appenzeller
- Department of Neurology, New Mexico Health Enhancement and Marathon Clinics Research Foundation, Albuquerque, NM 87122
| | - Yu Hsin Hsiao
- Division of Respiratory Medicine, Department of Pediatrics, University of California, San Diego, La Jolla, CA 92093
| | - Vineet Bafna
- Department of Computer Science and Engineering, University of California, San Diego, La Jolla, CA 92093
| | - Gabriel G Haddad
- Division of Respiratory Medicine, Department of Pediatrics, University of California, San Diego, La Jolla, CA 92093 .,Department of Neurosciences, University of California, San Diego, La Jolla, CA 92093.,Rady Children's Hospital, San Diego, CA 92123
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Villafuerte FC. New genetic and physiological factors for excessive erythrocytosis and Chronic Mountain Sickness. J Appl Physiol (1985) 2015; 119:1481-6. [PMID: 26272318 PMCID: PMC4683346 DOI: 10.1152/japplphysiol.00271.2015] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Accepted: 08/07/2015] [Indexed: 01/03/2023] Open
Abstract
In the last few years, genetic and functional studies have provided important insight on the pathophysiology of excessive erythrocytosis (EE), the main sign of Chronic Mountain Sickness (CMS). The recent finding of the association of the CMS phenotype with a single-nucleotide polymorphism (SNP) in the Sentrin-specific Protease 1 (SENP1) gene, and its differential expression pattern in Andean highlanders with and without CMS, has triggered large interest in high-altitude studies because of the potential role of its gene product in the control of erythropoiesis. The SENP1 gene encodes for a protease that regulates the function of hypoxia-relevant transcription factors such as Hypoxia-Inducible Factor (HIF) and GATA, and thus might have an erythropoietic regulatory role in CMS through the modulation of the expression of erythropoietin (Epo) or Epo receptors. The different physiological patterns in the Epo-EpoR system found among Andeans, even among highlanders with CMS, together with their different degrees of erythropoietic response, might indicate specific underlying genetic backgrounds, which in turn might reflect different levels of adaptation to lifelong high-altitude hypoxia. This minireview discusses recent genetic findings potentially underlying EE and CMS, and their possible physiological mechanisms in Andean highlanders.
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Affiliation(s)
- Francisco C Villafuerte
- Laboratorio de Fisiología Comparada, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Perú
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Villafuerte FC, Macarlupú JL, Anza-Ramírez C, Corrales-Melgar D, Vizcardo-Galindo G, Corante N, León-Velarde F. Decreased plasma soluble erythropoietin receptor in high-altitude excessive erythrocytosis and Chronic Mountain Sickness. J Appl Physiol (1985) 2014; 117:1356-62. [PMID: 25324511 PMCID: PMC4254844 DOI: 10.1152/japplphysiol.00619.2014] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Accepted: 10/13/2014] [Indexed: 11/22/2022] Open
Abstract
Excessive erythrocytosis (EE) is the hallmark of chronic mountain sickness (CMS), a prevalent syndrome in high-altitude Andean populations. Although hypoxemia represents its underlying stimulus, why some individuals develop EE despite having altitude-normal blood erythropoietin (Epo) concentration is still unclear. A soluble form of the Epo receptor (sEpoR) has been identified in human blood and competes directly for Epo with its membrane counterpart (mEpoR). Thus, reduced levels of circulating sEpoR could lead to higher Epo availability and ultimately to EE. We characterized the relationship between Epo and sEpoR, with hematocrit and hemoglobin concentration in healthy highlanders and CMS patients at 4,340 m in Cerro de Pasco, Peru. Our results show that EE patients show decreased plasma sEpoR levels and can be subdivided into two subgroups of normal and high plasma Epo concentration for the altitude of residence, with hemoglobin concentration rising exponentially with an increasing Epo-to-sEpoR ratio (Epo/sEpoR). Also, we showed that the latter varies as an inverse exponential function of arterial pulse O2 saturation. Our findings suggests that EE is strongly associated with higher Epo/sEpoR values, leading to elevated plasma Epo availability to bind mEpoR, and thereby a stronger stimulus for augmented erythropoiesis. Differences in the altitude normal and high Epo CMS patients with a progressively higher Epo/sEpoR supports the hypothesis of the existence of two genetically different subgroups suffering from EE and possibly different degrees of adaptation to chronic high-altitude hypoxia.
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Affiliation(s)
- Francisco C Villafuerte
- Laboratorio de Fisiología Comparada, Departamento de Ciencias Biológicas y Fisiológicas, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - José Luis Macarlupú
- Laboratorio de Fisiología Comparada, Departamento de Ciencias Biológicas y Fisiológicas, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Cecilia Anza-Ramírez
- Laboratorio de Fisiología Comparada, Departamento de Ciencias Biológicas y Fisiológicas, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Daniela Corrales-Melgar
- Laboratorio de Fisiología Comparada, Departamento de Ciencias Biológicas y Fisiológicas, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Gustavo Vizcardo-Galindo
- Laboratorio de Fisiología Comparada, Departamento de Ciencias Biológicas y Fisiológicas, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Noemí Corante
- Laboratorio de Fisiología Comparada, Departamento de Ciencias Biológicas y Fisiológicas, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Fabiola León-Velarde
- Laboratorio de Fisiología Comparada, Departamento de Ciencias Biológicas y Fisiológicas, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
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Rivera-Ch M, León-Velarde F, Huicho L. Treatment of chronic mountain sickness: critical reappraisal of an old problem. Respir Physiol Neurobiol 2007; 158:251-65. [PMID: 17580125 DOI: 10.1016/j.resp.2007.05.003] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2007] [Revised: 04/29/2007] [Accepted: 05/01/2007] [Indexed: 11/19/2022]
Abstract
A review is made on the different treatment strategies essayed to date in the management of chronic mountain sickness (CMS). After a brief presentation of the epidemiology and of the pathophysiological mechanisms proposed for explaining the disease, the advantages and drawbacks of the different treatment approaches are discussed, along with their pathopysiological rationale. A particular emphasis is dedicated to the scientific foundations underlying the development of acetazolamide and angiotensin-converting enzyme inhibitors as promising therapeutic agents for CMS, as well as the clinical evidence existing so far on their usefulness in the treatment of CMS. Various methodological issues that need to be addressed in future clinical studies on efficacy of therapies for CMS are discussed. There is also a brief discussion on potential treatment options for chronic high altitude pulmonary hypertension. Closing remarks on the need of taking increasingly into account the development and implementation of preventive measures are made.
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Affiliation(s)
- María Rivera-Ch
- Departamento de Ciencias Biológicas, Facultad de Ciencias y Filosofía, Instituto de Investigaciones de Altura, Universidad Peruana Cayetano Heredia, Av. Honorio Delgado 430, Lima LI 31, Peru.
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Abstract
This article summarizes recent advances in understanding the production and action of the hormone erythropoietin (Epo) with respect to high altitude physiology and sports medicine. Hypoxia is the main stimulus for Epo gene expression. An O2-labile protein (hypoxia-inducible factor 1, HIF-1) has been identified that is hydroxylated and degraded under normoxic conditions but active in hypoxia, where it enhances Epo gene transcription resulting in elevated hemoglobin levels and O2 capacity of the blood. The stimulation of Epo production at lowered arterial O2 tension can be maladaptive, if erythrocytosis develops such as seen in high altitude habitants. Within physiological limits the aerobic power increases in parallel with blood O2 capacity. Therefore, some elite athletes have misused recombinant human Epo (rhEpo), which is a beneficial anti-anemic drug in clinical practice. Indirect and direct methods to detect rhEpo doping have been recently developed.
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Affiliation(s)
- W Jelkmann
- Institute of Physiology, University of Lübeck, Lübeck, Germany.
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