Airway antioxidant capacity and pH in chronic obstructive pulmonary disease

Abstract

Wei Lee, Hsien Loo, Paul S. Thomas

Oxidant-antioxidant imbalance is implicated in the pathogenesis of chronic obstructive pulmonary disease (COPD). Exhaled breath condensate (EBC) is a novel and non-invasive method of assessing the redox status of the local airway in COPD subjects. It was hypothesized that COPD patients have less antioxidant capacity in their local airway as compared to the control subjects. The method involved collecting EBC from control and COPD patients (stable and during an exacerbation). Concentrations of EBC antioxidants, namely Trolox-equivalent antioxidant capacity (TEAC), bilirubin, urate and ascorbate, were analyzed using ELISA and high performance liquid chromatography. The mean TEAC level in the stable COPD group (11 ± 2 M) was significantly reduced compared to the ex-smokers & smokers (45 ± 11 M). The COPD group during an exacerbation had a mean bilirubin level of 0.22 ± 0.04 mg/dl, which was significantly lower than the stable COPD group (0.35 ± 0.01 mg/dl), and the non-smoking group (0.35 ± 0.02 mg/dl). Urate and ascorbic acid were undetectable. In conclusion, COPD patients are likely to have increased oxidative stress and reduced antioxidant capacity in their local airways.