Changes in the ratios of stable nitric oxide metabolites in the exhaled breath condensate in patients with COPD during antioxidant therapy

Abstract

The Study Aim: to investigate the correlations between stable nitric oxide metabolites in exhaled breath condensate (EBC) in patients with COPD during antioxidant therapy. Materials and Methods: The study included 88 patients: group 1 – COPD, stage I (GOLD spirometry classification) (n=47), group 2 – COPD, stage II (n=41). The control group consisted of 35 healthy volunteers. In all groups ECB samples were collected. In the experimental groups ECB was collected before and after the course of antioxidant therapy with N-acetylcysteine (NAC), 600 mg daily for 30 days. The EBC concentrations of nitrates (NO3-) and nitrites(NO2-) were determined by spectrophotometric method using the Griess reagent. The correlations between ECB NO3- and NO2- levels were studied during antioxidant therapy therapy. Results: It was found that NO3- and NO2- ECB levels in both experimental groups were significantly increased compared with control values. Control group showed strong positive correlation between the studied parameters (r = 0,98; p = 0,001) and linear coefficient k = 2,13 (k = {NO3-} / {NO2-}). There were no any correlations of studied parameters in both groups of COPD patients. However, significant linear correlation between NO3- and NO2- ECB levels (r = 0,87; p = 0.003) with a linear coefficient k = 2,5 was observed in group 1 after the NAC treatment. In COPD patients no significant changes in total NO3-/NO2- ECB levels were revealed after the antioxidant therapy therapy. Conclusion: NO3- and NO2- ECB levels reflect changes in nitric oxide cycle and can serve as a marker of antioxidant therapy efficacy.