Atypical hematological response to combined calorie restriction and chronic hypoxia in Biosphere 2 crew: a possible link to latent features of hibernation capacity.
Eight humans were isolated for 2 years in Biosphere 2, a sealed airtight habitat with recycled air, food, water, and wastes. A combination of conditions led to selective decline of oxygen (O2) in the internal atmosphere from 21% to 14%, inducing symptoms of high-altitude sickness but with little or no compensatory increase in red cell production. All crew members exhibited significant decreases in both erythrocyte 2,3-bisphosphoglycerate (2,3-BPG) concentrations and P50 [partial pressure of O2 for 50% hemoglobin (Hb) saturation] values, changes opposite those expected in adaptation to high-altitude hypoxia. Lower P50 with increased Hb-O2 affinity induced by low 2,3-BPG is a characteristic of hibernating species and could be advantageous in O2-impoverished environments. The mechanisms underlying these changes in the Biosphere 2 crew remain obscure but could be related to low-calorie diet (1750-2100 kcal/day). Because the combination of hypoxia and limited caloric intake is also characteristic of hibernation, this unusual response may represent a cross-adaptation phenomenon in which certain features of hibernation capability are expressed in humans.
Paglia
Donald E
DE
Department of Pathology and Laboratory Medicine, UCLA School of Medicine, Los Angeles, CA 90095-1732, USA. dpaglia@mcn.org
Walford
Roy L
RL
D019794:2,3-Diphosphoglycerate / Q000378:metabolism*; D000328:Adult; D000368:Aged; D000532:Altitude Sickness; D001831:Body Temperature; D031204:Caloric Restriction; D004032:Diet; D018504:Ecological Systems, Closed; D004912:Erythrocytes / Q000378:metabolism; D005260:Female; D006454:Hemoglobins; D006605:Hibernation / Q000502:physiology; D006801:Humans; D000860:Hypoxia; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000378:metabolism*; D010101:Oxygen Consumption; D010313:Partial Pressure
D006454:Hemoglobins; D019794:2,3-Diphosphoglycerate; D010100:Oxygen