Effects of race and sex on cerebral hemodynamics, oxygen delivery and blood flow distribution in response to high altitude

• Published in: Scientific reports Vol. 6; no. 1; p. 30500
• Main Authors: Liu, Jie, Liu, Yang, Ren, Li-hua, Li, Li, Wang, Zhen, Liu, Shan-shan, Li, Su-zhi, Cao, Tie-sheng
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 09.08.2016; Nature Publishing Group
• Subjects: 631/443/1338/1872; 631/443/1338/2729; 631/443/319/320; 692/308; 704/172/4081; Adaptation; Altitude; Analysis of Variance; Asian Continental Ancestry Group; Blood flow; Blood pressure; Brain - blood supply; Brain - physiology; Carotid Artery, Internal - diagnostic imaging; Carotid Artery, Internal - physiology; Cerebral blood flow; Cerebrovascular Circulation - physiology; Cerebrovascular system; Circulatory system; Continental Population Groups; Demography; Ethnic Groups; Female; Gender differences; Hemodynamics; Hemodynamics - physiology; Hemoglobin; High-altitude environments; Humanities and Social Sciences; Humans; Male; multidisciplinary; Oxygen; Oxygen - metabolism; Science; Sea level; Sex Characteristics; Sex differences; Ultrasonography; Ultrasound; Vertebrae; Vertebral Artery - diagnostic imaging; Vertebral Artery - physiology; Young Adult
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/srep30500

To assess racial, sexual and regional differences in cerebral hemodynamic response to high altitude (HA, 3658 m). We performed cross-sectional comparisons on total cerebral blood flow (TCBF = sum of bilateral internal carotid and vertebral arterial blood flows = Q ICA  + Q VA ), total cerebrovascular resistance (TCVR), total cerebral oxygen delivery (TCOD) and Q VA /TCBF (%), among six groups of young healthy subjects: Tibetans (2-year staying) and Han (Han Chinese) at sea level, Han (2-day, 1-year and 5-year) and Tibetans at HA. Bilateral ICA and VA diameters and flow velocities were derived from duplex ultrasonography; and simultaneous measurements of arterial pressure, oxygen saturation and hemoglobin concentration were conducted. Neither acute (2-day) nor chronic (>1 year) responses showed sex differences in Han, except that women showed lower TCOD compared with men. Tibetans and Han exhibited different chronic responses (percentage alteration relative to the sea-level counterpart value) in TCBF (−17% vs . 0%), TCVR (22% vs . 12%), TCOD (0% vs . 10%) and Q VA /TCBF (0% vs . 2.4%, absolute increase), with lower resting TCOD found in SL- and HA-Tibetans. Our findings indicate racial but not sex differences in cerebral hemodynamic adaptations to HA, with Tibetans (but not Han) demonstrating an altitude-related change of CBF distribution.