Cerebrovascular and ventilatory responses to acute isocapnic hypoxia in healthy aging and lung disease: effect of vitamin C.
J Appl Physiol (1985)
; 119(4): 363-73, 2015 Aug 15.
Article
em En
| MEDLINE
| ID: mdl-26089546
ABSTRACT
Acute hypoxia increases cerebral blood flow (CBF) and ventilation (VÌe). 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 cerebrovascular 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 (VÌp; index of CBF), and VÌe 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. VÌp and VÌe sensitivity to hypoxia was reduced in Older by â¼60% (P < 0.02). COPD patients exhibited similar VÌp and VÌe responses to Older (P > 0.05). Vitamin C did not have an effect on the hypoxic VÌe response but selectively decreased the VÌp 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.
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Base de dados:
MEDLINE
Assunto principal:
Ácido Ascórbico
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Envelhecimento
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Circulação Cerebrovascular
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Ventilação Pulmonar
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Doença Pulmonar Obstrutiva Crônica
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Pulmão
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Hipóxia
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Antioxidantes
Tipo de estudo:
Clinical_trials
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Diagnostic_studies
Limite:
Adult
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Aged
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Female
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Humans
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Male
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Middle aged
País como assunto:
America do norte
Idioma:
En
Ano de publicação:
2015
Tipo de documento:
Article