Cerebrovascular and ventilatory responses to acute isocapnic hypoxia in healthy aging and lung disease: effect of vitamin C
Sara E. Hartmann, Xavier Waltz, Christine K. Kissel, Lian Szabo, Brandie L. Walker, Richard Leigh, Todd J. Anderson, Marc J. Poulin
2015
Journal of applied physiology
Hartmann SE, Waltz X, Kissel CK, Szabo L, Walker BL, Leigh R, Anderson TJ, Poulin MJ. Cerebrovascular and ventilatory responses to acute isocapnic hypoxia in healthy aging and lung disease: effect of vitamin C. Acute hypoxia increases cerebral blood flow (CBF) and ventilation (V E). It is unknown if these responses are impacted with normal aging, or in patients with enhanced oxidative stress, such as (COPD). The purpose of the study was to 1) investigate the effects of aging and COPD on the
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... brovascular and ventilatory responses to acute hypoxia, and 2) to assess the effect of vitamin C on these responses during hypoxia. In 12 Younger, 14 Older, and 12 COPD, we measured peak cerebral blood flow velocity (V P; index of CBF), and V E during two 5-min periods of acute isocapnic hypoxia, under conditions of 1) saline-sham; and 2) intravenous vitamin C. Antioxidants [vitamin C, superoxide dismutase (SOD), glutathione peroxidase, and catalase], oxidative stress [malondialdehyde (MDA) and advanced protein oxidation product], and nitric oxide metabolism end products (NOx) were measured in plasma. Following the administration of vitamin C, vitamin C, SOD, catalase, and MDA increased, while NOx decreased. V P and V E sensitivity to hypoxia was reduced in Older by ϳ60% (P Ͻ 0.02). COPD patients exhibited similar V P and V E responses to Older (P Ͼ 0.05). Vitamin C did not have an effect on the hypoxic V E response but selectively decreased the V P sensitivity in Younger only. These findings suggest a reduced integrative reflex (i.e., cerebrovascular and ventilatory) during acute hypoxemia in healthy older adults. Vitamin C does not appear to have a large influence on the cerebrovascular or ventilatory responses during acute hypoxia. Downloaded from Fig. 2. A-D: A, plasma markers of vitamin C and antioxidant enzyme activities [(B) catalase]; C, superoxide dismutase (SOD), and D, glutathione peroxidase (GPX)] in Younger, Older, and COPD patients at baseline (BL), saline (SAL), and following vitamin C infusion. Values represent means Ϯ SD. 369 Effect of Aging and COPD on the Hypoxic Response • Hartmann SE et al.
doi:10.1152/japplphysiol.00389.2015
pmid:26089546
fatcat:asnh2bfwzfbi7jwqmsa2lqyup4