BACKGROUND AND PURPOSE: Andean highlanders, unlike Ethiopians, develop chronic mountain sickness (CMS), a maladaptation to their native land. Ambient hypoxia induces NO-mediated vasodilatation. Fitness for life at altitude might be revealed by cerebrovascular responses to NO. METHODS: Nine altitude-native men were examined at 3622 and 794 m in Ethiopia and compared with 9 altitude-native Andean men tested at 4338 and 150 m in Peru. We assessed CMS scores, hematocrits, end-tidal pressure of carbon dioxide (P(ET)co2), oxygen saturations, and cerebral blood flow velocity (CBV). We evaluated fitness for life at altitude from the cerebrovascular response to an exogenous NO donor. RESULTS: At high altitude, CMS scores and hematocrits were higher in Andeans, and they had lower oxygen saturations. Ethiopians had higher P(ET)co2 at all study sites. At low altitude, saturations were similar in both groups. Responsiveness of the cerebral circulation to NO was minimal in Ethiopians at low altitude, whereas Andeans had a large response. In contrast, at high altitude, Ethiopians showed large responses, and Peruvians had minimal responses. CONCLUSIONS: By our measure, high altitude-native Peruvians were well-adapted lowlanders, whereas Ethiopian highlanders were well adapted to altitude life. Environmental pressures were sufficient for human adaptation to chronic hypoxia in Africa but not South America. The mechanisms underlying these differences are unknown, although studies of neurovascular diseases suggest that this may be related to a NO receptor polymorphism.
BACKGROUND AND PURPOSE: Andean highlanders, unlike Ethiopians, develop chronic mountain sickness (CMS), a maladaptation to their native land. Ambient hypoxia induces NO-mediated vasodilatation. Fitness for life at altitude might be revealed by cerebrovascular responses to NO. METHODS: Nine altitude-native men were examined at 3622 and 794 m in Ethiopia and compared with 9 altitude-native Andean men tested at 4338 and 150 m in Peru. We assessed CMS scores, hematocrits, end-tidal pressure of carbon dioxide (P(ET)co2), oxygen saturations, and cerebral blood flow velocity (CBV). We evaluated fitness for life at altitude from the cerebrovascular response to an exogenous NO donor. RESULTS: At high altitude, CMS scores and hematocrits were higher in Andeans, and they had lower oxygen saturations. Ethiopians had higher P(ET)co2 at all study sites. At low altitude, saturations were similar in both groups. Responsiveness of the cerebral circulation to NO was minimal in Ethiopians at low altitude, whereas Andeans had a large response. In contrast, at high altitude, Ethiopians showed large responses, and Peruvians had minimal responses. CONCLUSIONS: By our measure, high altitude-native Peruvians were well-adapted lowlanders, whereas Ethiopian highlanders were well adapted to altitude life. Environmental pressures were sufficient for human adaptation to chronic hypoxia in Africa but not South America. The mechanisms underlying these differences are unknown, although studies of neurovascular diseases suggest that this may be related to a NO receptor polymorphism.
Authors: M Slessarev; E Prisman; S Ito; R R Watson; D Jensen; D Preiss; R Greene; T Norboo; T Stobdan; D Diskit; A Norboo; M Kunzang; O Appenzeller; J Duffin; J A Fisher Journal: J Physiol Date: 2010-03-01 Impact factor: 5.182
Authors: Marat Slessarev; Alexandra Mardimae; David Preiss; Alex Vesely; Dahlia Y Balaban; Richard Greene; James Duffin; Joseph A Fisher Journal: J Physiol Date: 2010-03-15 Impact factor: 5.182
Authors: D M Bailey; K A Evans; P E James; J McEneny; I S Young; L Fall; M Gutowski; E Kewley; J M McCord; Kirsten Møller; P N Ainslie Journal: J Physiol Date: 2008-10-20 Impact factor: 5.182
Authors: Nitin Udpa; Roy Ronen; Dan Zhou; Junbin Liang; Tsering Stobdan; Otto Appenzeller; Ye Yin; Yuanping Du; Lixia Guo; Rui Cao; Yu Wang; Xin Jin; Chen Huang; Wenlong Jia; Dandan Cao; Guangwu Guo; Victoria E Claydon; Roger Hainsworth; Jorge L Gamboa; Mehila Zibenigus; Guta Zenebe; Jin Xue; Siqi Liu; Kelly A Frazer; Yingrui Li; Vineet Bafna; Gabriel G Haddad Journal: Genome Biol Date: 2014-02-20 Impact factor: 13.583