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Droma Y, Ota M, Kobayashi N, Ito M, Kobayashi T, Hanaoka M. Genetic Associations with the Susceptibility to High-Altitude Pulmonary Edema in the Japanese Population. High Alt Med Biol 2025. [PMID: 40094446 DOI: 10.1089/ham.2024.0119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/19/2025] Open
Abstract
Yunden Droma, Masao Ota, Nobumitsu Kobayashi, Michiko Ito, Toshio Kobayashi, and Masayuki Hanaoka. Genetic Associations with the Susceptibility to High-Altitude Pulmonary Edema in the Japanese Population. High Alt Med Biol. 00:00-00, 2025.-High-altitude pulmonary edema (HAPE) is a life-threatening, noncardiogenic pulmonary condition that may occur in individuals rapidly ascending to altitudes higher than 2,500 m above sea level. Exaggerated hypoxia-induced pulmonary hypertension plays a critical role in its pathophysiological mechanism. In addition to environmental factors such as hypoxia and hypobaria at high altitudes, individual genetic predisposition significantly influences HAPE occurrence. Several candidate genes have been proposed based on the pathophysiology of HAPE, particularly involving the hypoxia-induced factor pathway and vasodilators/vasoconstrictors. Over the past two decades, we have investigated the associations between susceptibility to HAPE and these candidate genes, including genes EPAS1 (endothelial Per-ARNT-Sim [PAS] domain protein 1), EGLN1 (egl-9 family hypoxia inducible factor 1), eNOS (endothelial nitric oxide synthase), ACE (angiotensin-converting enzyme), and TIMP3 (tissue inhibitor of metalloproteinase 3) in the Japanese population. This review summarizes the major findings of these studies, shedding light on genetic associations with HAPE in the Japanese population.
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Affiliation(s)
- Yunden Droma
- First Department of Internal Medicine, Shinshu University School of Medicine, Matsumoto, Japan
| | - Masao Ota
- Division of Hepatology and Gastroenterology, Department of Internal Medicine, Shinshu University School of Medicine, Matsumoto, Japan
| | - Nobumitsu Kobayashi
- First Department of Internal Medicine, Shinshu University School of Medicine, Matsumoto, Japan
| | - Michiko Ito
- First Department of Internal Medicine, Shinshu University School of Medicine, Matsumoto, Japan
| | - Toshio Kobayashi
- Department of Internal Medicine, Kakeyu Misayama Rehabilitation Center, Ueda, Japan
| | - Masayuki Hanaoka
- First Department of Internal Medicine, Shinshu University School of Medicine, Matsumoto, Japan
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Fabries P, Drogou C, Sauvet F, Nespoulous O, Erkel MC, Marchandot V, Bouaziz W, Lepetit B, Hamm-Hornez AP, Malgoyre A, Koulmann N, Gomez-Merino D, Chennaoui M. The HMOX2 polymorphism contributes to the carotid body chemoreflex in European sea-level residents by regulating hypoxic ventilatory responses. Front Med (Lausanne) 2022; 9:1000786. [PMID: 36405624 PMCID: PMC9669423 DOI: 10.3389/fmed.2022.1000786] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Accepted: 10/17/2022] [Indexed: 10/18/2023] Open
Abstract
This study investigates whether a functional single nucleotide polymorphism of HMOX2 (heme oxygenase-2) (rs4786504 T>C) is involved in individual chemosensitivity to acute hypoxia, as assessed by ventilatory responses, in European individuals. These responses were obtained at rest and during submaximal exercise, using a standardized and validated protocol for exposure to acute normobaric hypoxia. Carriers of the ancestral T allele (n = 44) have significantly lower resting and exercise hypoxic ventilatory responses than C/C homozygous carriers (n = 40). In the literature, a hypoxic ventilatory response threshold to exercise has been identified as an independent predictor of severe high altitude-illness (SHAI). Our study shows that carriers of the T allele have a higher risk of SHAI than carriers of the mutated C/C genotype. Secondarily, we were also interested in COMT (rs4680 G > A) polymorphism, which may be indirectly involved in the chemoreflex response through modulation of autonomic nervous system activity. Significant differences are present between COMT genotypes for oxygen saturation and ventilatory responses to hypoxia at rest. In conclusion, this study adds information on genetic factors involved in individual vulnerability to acute hypoxia and supports the critical role of the ≪ O2 sensor ≫ - heme oxygenase-2 - in the chemosensitivity of carotid bodies in Humans.
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Affiliation(s)
- Pierre Fabries
- French Armed Forces Biomedical Research Institute – IRBA, Brétigny-sur-Orge, France
- French Military Health Academy - Ecole du Val-de-Grâce, Paris, France
- Laboratoire de Biologie de l'Exercice pour la Performance et la Santé – LBEPS – UMR, Université Paris-Saclay, IRBA, Evry-Courcouronnes, France
| | - Catherine Drogou
- French Armed Forces Biomedical Research Institute – IRBA, Brétigny-sur-Orge, France
- Vigilance Fatigue Sommeil et Santé Publique – VIFASOM – UPR 7330, Université de Paris Cité, Paris, France
| | - Fabien Sauvet
- French Armed Forces Biomedical Research Institute – IRBA, Brétigny-sur-Orge, France
- French Military Health Academy - Ecole du Val-de-Grâce, Paris, France
- Vigilance Fatigue Sommeil et Santé Publique – VIFASOM – UPR 7330, Université de Paris Cité, Paris, France
| | - Olivier Nespoulous
- French Armed Forces Biomedical Research Institute – IRBA, Brétigny-sur-Orge, France
| | - Marie-Claire Erkel
- French Armed Forces Biomedical Research Institute – IRBA, Brétigny-sur-Orge, France
- Vigilance Fatigue Sommeil et Santé Publique – VIFASOM – UPR 7330, Université de Paris Cité, Paris, France
| | | | - Walid Bouaziz
- French Armed Forces Biomedical Research Institute – IRBA, Brétigny-sur-Orge, France
| | - Benoît Lepetit
- French Armed Forces Biomedical Research Institute – IRBA, Brétigny-sur-Orge, France
- Laboratoire de Biologie de l'Exercice pour la Performance et la Santé – LBEPS – UMR, Université Paris-Saclay, IRBA, Evry-Courcouronnes, France
| | | | - Alexandra Malgoyre
- French Armed Forces Biomedical Research Institute – IRBA, Brétigny-sur-Orge, France
- Laboratoire de Biologie de l'Exercice pour la Performance et la Santé – LBEPS – UMR, Université Paris-Saclay, IRBA, Evry-Courcouronnes, France
| | - Nathalie Koulmann
- French Military Health Academy - Ecole du Val-de-Grâce, Paris, France
- Laboratoire de Biologie de l'Exercice pour la Performance et la Santé – LBEPS – UMR, Université Paris-Saclay, IRBA, Evry-Courcouronnes, France
| | - Danielle Gomez-Merino
- French Armed Forces Biomedical Research Institute – IRBA, Brétigny-sur-Orge, France
- Vigilance Fatigue Sommeil et Santé Publique – VIFASOM – UPR 7330, Université de Paris Cité, Paris, France
| | - Mounir Chennaoui
- French Armed Forces Biomedical Research Institute – IRBA, Brétigny-sur-Orge, France
- Vigilance Fatigue Sommeil et Santé Publique – VIFASOM – UPR 7330, Université de Paris Cité, Paris, France
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Yan Y, Zhang X, Ren H, An X, Fan W, Liang J, Huang Y. Anterior Circulation Acute Ischemic Stroke in the Plateau of China: Risk Factors and Clinical Characteristics. Front Neurol 2022; 13:859616. [PMID: 35493834 PMCID: PMC9043326 DOI: 10.3389/fneur.2022.859616] [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: 01/21/2022] [Accepted: 03/15/2022] [Indexed: 11/30/2022] Open
Abstract
Background and Purpose Acute ischemic stroke has a high incidence in the plateau of China. It has unique characteristics compared to the plains, and the specific relationship with altitude has not yet been appreciated. This study aimed to investigate the specificity of the plateau's anterior circulation acute ischemic stroke in China. Methods To retrospectively collect clinical data of patients with first-episode acute ischemic stroke in the anterior circulation in Tianjin and Xining city. The differences in clinical presentation, laboratory, and imaging examinations were compared. Results Patients at high altitudes showed a significant trend toward lower age (61.0 ± 10.2 vs. 64.8 ± 8.1, P = 0.010) and had a history of dyslipidemia, higher levels of inflammatory markers, erythrocytosis, and alcohol abuse. The main manifestations were higher diastolic blood pressure (85.5 ± 14.0 mmHg vs. 76.8 ± 11.6 mmHg, P < 0.001), triglycerides [2.0 (1.8) mmol/L vs. 1.3 (0.9) mmol/L, P < 0.001], CRP [4.7 (4.4) mg/L vs. 2.1 (1.9) mg/L, P < 0.001], homocysteine levels [14.5 (11.7) μmol/L vs. 11.2 (5.2) μmol/L, P < 0.001]; larger infarct volume [3.5 (4.8) cm3 vs. 9.0 (6.9) cm3, P < 0.001] and worse prognosis. Patients at high altitudes had higher atherosclerotic indexes in cIMT and plaque than those in plains. Conclusions The natural habituation and genetic adaptation of people to the particular geo-climatic environment of the plateau have resulted in significant differences in disease characteristics. Patients with the anterior circulation acute ischemic stroke in the plateau show more unfavorable clinical manifestations and prognosis. This study provides a preliminary interpretation of the effects of altitude and suggests developing preventive and therapeutic protocol measures that are more appropriate for the plateau of China.
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Affiliation(s)
- Yujia Yan
- Department of Neurosurgery, Tianjin University Huanhu Hospital, Tianjin, China
- Academy of Medical Engineering and Translational Medicine, Tianjin University, Tianjin, China
| | - Xiqiang Zhang
- Department of Neurosurgery, Third People Hospital of Xining City, Xining, China
| | - Hecheng Ren
- Department of Neurosurgery, Tianjin University Huanhu Hospital, Tianjin, China
| | - Xingwei An
- Academy of Medical Engineering and Translational Medicine, Tianjin University, Tianjin, China
- Tianjin Center for Brain Science, Tianjin, China
| | - Wanpeng Fan
- Department of Neurosurgery, Third People Hospital of Xining City, Xining, China
| | - Jingbo Liang
- Department of Neurosurgery, Third People Hospital of Xining City, Xining, China
| | - Ying Huang
- Department of Neurosurgery, Tianjin University Huanhu Hospital, Tianjin, China
- Academy of Medical Engineering and Translational Medicine, Tianjin University, Tianjin, China
- *Correspondence: Ying Huang
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Abstract
PURPOSE OF REVIEW The relationship of altitude and cold to cardiovascular risk is complex. Cold is hard to separate from altitude. This review highlights the latest information on cardiovascular disease associated with high altitude and cold; both represent unique clinical situations. RECENT FINDINGS Evolution and genetics are relevant to high altitude, with much new information available. Specific physiology explains some congenital heart disease at altitude. New reports of hematological changes associated with altitude and cold help clarify thrombosis, which is relevant to reports of very late in-stent thrombosis at altitude. Multiple cardiovascular risk factors are affected by altitude and cold, and an increased incidence of myocardial infarction occurs. There is new research on acute mountain sickness associated with inflammation with relevance for clinical study of pulmonary edema. Socioeconomics plays a part in altitude and cold effects on cardiovascular disease. In addition to acute disease, high altitude involves chronic mountain sickness with new knowledge of associated cardiovascular endothelial abnormalities. SUMMARY High altitude and cold involve acute disease, chronic disease, and public health issues. Continued research is essential to enable the best clinical management in this era of rapid worldwide travel.
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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: 3.4] [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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Abstract
High altitude pulmonary oedema (HAPE) is an important and preventable cause of death at high altitudes. However, little is known about the global incidence of HAPE, in part because most cases occur in remote environments where no records are kept. Furthermore, despite international efforts to achieve consensus, there is wide disparity in the diagnostic criteria in clinical and research use. We have reviewed the literature on the incidence and epidemiology of HAPE. There is broad agreement between studies that HAPE incidence at 2500m is around 0.01%, and increases to 1.9% at 3600m and 2.5-5% at 4300m. Risk factors for HAPE include rate of ascent, intensity of exercise and absolute altitude attained, although an individual pre-disposition to developing the condition is also well described and suggests an underlying genetic susceptibility. It is increasingly recognised that clinically-detectable HAPE is an extreme of a continuous spectrum of excess pulmonary fluid accumulation, which has been demonstrated in asymptomatic individuals. There is a continued need to ensure awareness of the diagnosis and treatment of HAPE among visitors to high altitude. It is likely that HAPE is preventable in all cases by progressive acclimatisation, and we advocate a pragmatic "golden rules" approach. Our understanding of the epidemiology and underlying genetic susceptibility to HAPE may be advanced if susceptible individuals register with the International HAPE Database: http://www.altitude.org/hape.php. HAPE has direct relevance to military training and operations and is likely to be the leading cause of death at high altitude.
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Affiliation(s)
- D P Hall
- Royal Infirmary of Edinburgh, Edinburgh, UK
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MacInnis MJ, Koehle MS, Rupert JL. Evidence for a genetic basis for altitude illness: 2010 update. High Alt Med Biol 2011; 11:349-68. [PMID: 21190504 DOI: 10.1089/ham.2010.1030] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Altitude illness refers to a group of environmentally mediated pathophysiologies. Many people will suffer acute mountain sickness shortly after rapidly ascending to a moderately hypoxic environment, and an unfortunate few will develop potentially fatal conditions such as high altitude pulmonary edema or high altitude cerebral edema. Some individuals seem to be predisposed to developing altitude illness, suggesting an innate contribution to susceptibility. The implication that there are altitude-sensitive and altitude-tolerant individuals has stimulated much research into the contribution of a genetic background to the efficacy of altitude acclimatization. Although the effect of altitude attained and rate of ascent on the etiology of altitude illness is well known, there are only tantalizing, but rapidly accumulating, clues to the genes that may be involved. In 2006, we reviewed what was then known about the genetics of altitude illness. This article updates that review and attempts to tabulate all the available genetic data pertaining to these conditions. To date, 58 genes have been investigated for a role in altitude illness. Of these, 17 have shown some association with the susceptibility to, or the severity of, these conditions, although in many cases the effect size is small or variable. Caution is recommended when evaluating the genes for which no association was detected, because a number of the investigations reviewed in this article were insufficiently powered to detect small effects. No study has demonstrated a clear-cut altitude illness gene, but the accumulating data are consistent with a polygenic condition with a strong environmental component. The genes that have shown an association affect a variety of biological pathways, suggesting that either multiple systems are involved in altitude pathophysiology or that gene-gene interactions play a role. Although numerous studies have been performed to investigate specific genes, few have looked for evidence of heritability or familial transmission, or for epidemiological patterns that would be consistent with genetically influenced conditions. Future trends, such as genome-wide association studies and epigenetic analysis, should lead to enhanced understanding of the complex interactions within the genome and between the genome and hypoxic environments that contribute to an individual's capacity to acclimatize rapidly and effectively to altitude.
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Affiliation(s)
- Martin J MacInnis
- School of Human Kinetics, University of British Columbia, 6081 University Boulevard, Vancouver, BC, Canada
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Pasha MAQ, Newman JH. High-altitude disorders: pulmonary hypertension: pulmonary vascular disease: the global perspective. Chest 2010; 137:13S-19S. [PMID: 20522576 DOI: 10.1378/chest.09-2445] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Globally, it is estimated that > 140 million people live at a high altitude (HA), defined as > 2,500 m (8,200 ft), and that countless others sojourn to the mountains for work, travel, and sport. The distribution of exposure to HA is worldwide, including 35 million in the Andes and > 80 million in Asia, including China and central Asia. HA stress primarily is due to the hypoxia of low atmospheric pressure, but dry air, intense solar radiation, extreme cold, and exercise contribute to acute and chronic disorders. The acute disorders are acute mountain sickness (also known as soroche), HA cerebral edema, and HA pulmonary edema (HAPE). Of these, HAPE is highly correlated with acute pulmonary hypertension. The first chronic syndrome described in HA dwellers in Peru was chronic mountain sickness (Monge disease), which has a large component of relative hypoventilation and secondary erythrocytosis. The prevalence of chronic mountain sickness in HA dwellers ranges from 1.2% in native Tibetans to 5.6% in Chinese Han; 6% to 8% in male residents of La Paz, Bolivia; and 15.6% in the Andes. Subacute mountain sickness is an exaggerated pulmonary hypertensive response to HA hypoxia occurring over months, most often in infants and very young children. Chronic pulmonary hypertension with heart failure but without hypoventilation is seen in Asia. Not only does HA pulmonary hypertension exact health consequences for the millions affected, but also the mechanisms of disease relate to pulmonary hypertension associated with multiple other disorders. Genetic understanding of these disorders is in its infancy.
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Liu SZ, Yan H, Hou WK, Xu P, Tian J, Tian LF, Zhu BF, Ma J, Lu SM. Relationships between endothelial nitric oxide synthase gene polymorphisms and osteoporosis in postmenopausal women. J Zhejiang Univ Sci B 2009; 10:609-18. [PMID: 19650200 DOI: 10.1631/jzus.b0920137] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
OBJECTIVE To investigate the relationships between endothelial nitric oxide synthases (eNOS) G894T and 27 bp-variable number tandem repeat (VNTR) gene polymorphisms and osteoporosis in the postmenopausal women of Chinese Han nationality. METHODS In the present study, 281 postmenopausal women from Xi'an urban area in West China were recruited, and divided into osteoporosis, osteopenia, and normal groups according to the diagnostic criteria of osteoporosis proposed by World Health Organization (WHO). The bone mineral density (BMD) values of lumbar vertebrae and left hips were determined by QDR-2000 dual energy X-ray absorptiometry. Blood samples were tested for plasma biochemical indicators including testosterone, estradiol, calcitonin, osteocalcin, and procollagen type I amino-terminal propeptide by enzyme-linked immunosorbent assay (ELISA), tartrate-resistant acid phosphatase by spectrophotometric method, and the content of nitric oxide by Griess method. Genome DNA was extracted from whole blood, and G894T polymorphism of eNOS gene was analyzed by using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method and 27 bp-VNTR polymorphism of eNOS gene was genotyped by PCR method. Then the relationships between genotypes and biochemical indicators, genotypes and osteoporosis, and haplotypes and osteoporosis were analyzed. RESULTS The average BMD values of the femoral neck, ward's triangle and lumbar vertebrae 1-4 (L1-L4) in the subjects with T/T genotype in eNOS G894T locus were significantly higher than those in the subjects with G/T and G/G genotypes (P<0.05). The average BMD of the femoral neck in the subjects with a/a genotype of eNOS 27 bp-VNTR locus was evidently higher than that in the subjects with b/b genotype (P<0.05). The plasma testosterone and osteocalcin concentrations in the subjects of eNOS G894T G/T genotype were evidently higher than those in the subjects of other genotypes (P<0.05); the plasma estradiol concentration in the subjects of eNOS 27 bp-VNTR a/a genotype was obviously higher than that in the subjects of b/b genotype (P<0.01). eNOS G/G homozygous frequencies in osteoporosis women, osteopenia women, and normal women were 85.37%, 76.38%, and 83.87%, respectively (P>0.05). 0% osteoporosis woman, 0.79% osteopenia women, and 3.23% normal women were eNOS a/a homozygous (P<0.05). The frequencies of eNOS 27 bp-VNTR a allele were 5.33% in the osteoporosis group, 10.24% in the osteopenia group, and 16.13% in the normal group (P<0.05, odds ratio (OR)=0.29, 95% confidence interval (CI)=0.11-0.77), suggesting that a/a genotype and a allele might have protective effects on osteoporosis. The haplotype analysis showed that G-b was 87.7% (214/244) in the osteoporosis group (P<0.05, OR=2.48, 95% CI=1.18-5.18). G-a was 5.3% (13/244) in the osteoporosis group (P<0.05, OR=0.29, 95% CI=0.11-0.77). G-b was a risk factor for osteoporosis, and G-a a protective factor. CONCLUSION eNOS G894T G/T genotype influenced the plasma testosterone and osteocalcin concentrations, and T/T genotype influenced BMD. eNOS 27 bp-VNTR a/a genotype increased plasma estradiol concentration to have a protective effect on osteoporosis.
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Affiliation(s)
- Shun-zhi Liu
- Department of Public Health, School of Medicine, Xi'an Jiaotong University, Xi'an 710061, China
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Dunin-Bell O, Boyle S. Secondary Prevention of HAPE in a Mount Everest Summiteer. High Alt Med Biol 2009; 10:293-6. [DOI: 10.1089/ham.2008.1094] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Grocott M, Montgomery H. Genetophysiology: Using Genetic Strategies to Explore Hypoxic Adaptation. High Alt Med Biol 2008; 9:123-9. [DOI: 10.1089/ham.2008.1012] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Mike Grocott
- UCL Institute for Human Health and Performance, London, United Kingdom
| | - Hugh Montgomery
- UCL Institute for Human Health and Performance, London, United Kingdom
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12
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Stobdan T, Karar J, Pasha MAQ. High Altitude Adaptation: Genetic Perspectives. High Alt Med Biol 2008; 9:140-7. [DOI: 10.1089/ham.2007.1076] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Tsering Stobdan
- Institute of Genomics and Integrative Biology, Delhi, India, and Department of Biotechnology, University of Pune, Pune, India
| | - Jayashree Karar
- Institute of Genomics and Integrative Biology, Delhi, India, and Department of Biotechnology, University of Pune, Pune, India
| | - M. A. Qadar Pasha
- Institute of Genomics and Integrative Biology, Delhi, India, and Department of Biotechnology, University of Pune, Pune, India
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Dehnert C, Berger MM, Mairbäurl H, Bärtsch P. High altitude pulmonary edema: a pressure-induced leak. Respir Physiol Neurobiol 2007; 158:266-73. [PMID: 17602898 DOI: 10.1016/j.resp.2007.05.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2007] [Revised: 04/30/2007] [Accepted: 05/01/2007] [Indexed: 10/23/2022]
Abstract
High altitude pulmonary edema (HAPE) is a non-cardiogenic pulmonary edema that can occur in healthy individuals who ascend rapidly to altitudes above 3000-4000m. Excessive pulmonary artery pressure (PAP) is crucial for the development of HAPE, since lowering pulmonary artery pressure by nifedipine or tadalafil (phosphodiesterase-5-inhibitor) will in most cases prevent HAPE. Recent studies using microspheres in swine and magnetic resonance imaging in humans strongly support the concept and primacy of nonuniform hypoxic arteriolar vasoconstriction to explain how hypoxic pulmonary vasoconstriction occurring predominantly at the arteriolar level can cause leakage. Evidence is accumulating that the excessive PAP response in HAPE-susceptible individuals is due to a reduced NO bioavailability. HAPE-susceptible individuals show an endothelial dysfunction in the systemic circulation in hypoxia. Lower levels of exhaled NO in hypoxia before and during HAPE suggest that this abnormality also occurs in the lungs and polymorphisms of the eNOS gene are associated with susceptibility to HAPE in the Indian and Japanese population.
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Affiliation(s)
- Christoph Dehnert
- Medical University Clinic, Department of Internal Medicine, Div. of Sports Medicine, Im Neuenheimer Feld 410, D - 69120 Heidelberg, Germany
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Grocott M, Montgomery H, Vercueil A. High-altitude physiology and pathophysiology: implications and relevance for intensive care medicine. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2007; 11:203. [PMID: 17291330 PMCID: PMC2151873 DOI: 10.1186/cc5142] [Citation(s) in RCA: 135] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Cellular hypoxia is a fundamental mechanism of injury in the critically ill. The study of human responses to hypoxia occurring as a consequence of hypobaria defines the fields of high-altitude medicine and physiology. A new paradigm suggests that the physiological and pathophysiological responses to extreme environmental challenges (for example, hypobaric hypoxia, hyper-baria, microgravity, cold, heat) may be similar to responses seen in critical illness. The present review explores the idea that human responses to the hypoxia of high altitude may be used as a means of exploring elements of the pathophysiology of critical illness.
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Affiliation(s)
- Michael Grocott
- Centre for Altitude, Space and Extreme Environment Medicine (CASE Medicine), UCL Institute of Human Health and Performance, UCL Archway Campus, Highgate Hill, London, UK.
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Sartori C, Allemann Y, Scherrer U. Pathogenesis of pulmonary edema: learning from high-altitude pulmonary edema. Respir Physiol Neurobiol 2007; 159:338-49. [PMID: 17532272 DOI: 10.1016/j.resp.2007.04.006] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2006] [Revised: 04/05/2007] [Accepted: 04/10/2007] [Indexed: 01/07/2023]
Abstract
Pulmonary edema is a problem of major clinical importance resulting from a persistent imbalance between forces that drive water into the airspace of the lung and the biological mechanisms for its removal. Here, we will review the fundamental mechanisms implicated in the regulation of alveolar fluid homeostasis. We will then describe the perturbations of pulmonary fluid homeostasis implicated in the pathogenesis of pulmonary edema in conditions associated with increased pulmonary capillary pressure, namely cardiogenic pulmonary edema and high-altitude pulmonary edema (HAPE), with particular emphasis on the latter that has provided important new insight into underlying mechanisms of pulmonary edema. We will provide evidence that impaired pulmonary endothelial and epithelial nitric oxide synthesis and/or bioavailability may represent a central underlying defect predisposing to exaggerated hypoxic pulmonary vasoconstriction, and, in turn, capillary stress failure and alveolar fluid flooding. We will then demonstrate that exaggerated pulmonary hypertension, while possibly a prerequisite, may not always be sufficient to cause HAPE, and how defective alveolar fluid clearance may represent a second important pathogenic mechanism. Finally, we will outline, how this new insight gained from studies in HAPE, may be translated into the management of pulmonary edema and hypoxemia related disease states in general.
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Affiliation(s)
- Claudio Sartori
- Department of Internal Medicine and the Botnar Center for Extreme Medicine, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland
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