Decreased cerebrovascular response to CO2 in post-menopausal females with COPD: role of oxidative stress.

Chronic obstructive pulmonary disease (COPD) is associated with cerebrovascular abnormalities and an overproduction of reactive oxygen species. We hypothesised that COPD patients have oxidant-related cerebrovascular dysfunction. Our main objective was to evaluate cerebrovascular reactivity and its relationship with oxidative stress in females with COPD. We studied eight females with moderate COPD and 10 healthy female control subjects of similar age. Transcranial Doppler ultrasound assessed cerebral blood flow (CBF) velocity during hypercapnia. Plasma was assessed at rest for DNA oxidation, advanced oxidation protein products, lipid peroxidation, nitrotyrosine, antioxidant enzyme activity (glutathione peroxidase and catalase) and end-products of nitric oxide metabolism. Moderate COPD patients showed decreased cerebrovascular sensitivity to carbon dioxide (CO(2)) (COPD 1.17 ± 0.54 versus control 2.15 ± 0.73 cm · s(-1) · mmHg(-1); p<0.01). COPD patients had higher levels of DNA and lipid oxidation, advanced oxidation protein products and higher glutathione peroxidase activity (p<0.05). Controlling for measures of oxidative stress (DNA and lipid oxidation, and advanced oxidation protein product) eliminates statistically significant differences between the COPD and control groups in the CBF sensitivity to CO(2). Females with moderate COPD were found to have cerebrovascular dysfunction. Our results suggest that increased levels of systemic oxidative stress may have implications in the cerebrovascular dysfunction observed during hypercapnia in COPD.