Clinical immunology
The effects of N-acetylcysteine and inhaled steroid on inflammatory and oxidative stress markers in chronic obstructive pulmonary disease (COPD)

Introduction: Chronic obstructive pulmonary disease (COPD) is characterised by chronic airway inflammation with increased numbers of neutrophils in the airway lumen. Inhaled corticosteroids are widely used for the treatment of COPD despite of controversial statements concerning their efficiency. N-acetylcysteine is a mucolytic drug with antioxidant properties, counteracting the oxidant/antioxidant imbalance in COPD.

Objectives: The aim of the present study is to evaluate whether treatment of COPD patients with inhaled corticosteroid or N-acetylcysteine will change indices of inflammation and oxidative stress.

Material and Methods: Twenty COPD patients are treated for two times 10 weeks with fluticasone dipropionate (1000 µg/day) or N-acetylcysteine (600 mg/day) in a randomised crossover setting. Induced sputum and blood samples were collected every 10 weeks.

Results: Protective markers for oxidative stress, glutathione peroxidase (47.5±5.3 vs. 57.6±7.8 U/g Hb, P<0.05) and trolox-equivalent antioxidant capacity (1.41±0.05 vs. 1.50±0.06 mM, P<0.05) were increased by steroid treatment. N-acetylcysteine decreased significantly sputum eosinophil cationic protein (266±61 vs. 136±27 ng/ml, P<0.02), sputum interleukin-8 (403±65 vs. 326±62 ng/ml, P=0.05), and sputum tryptase, a serine protease (1.80±0.29 vs. 1.33±0.16 ng/ml, P<0.01).

Conclusions: These results suggest inhaled steroids have no action on inflammatory indices in the treatment of COPD, while N-acetylcysteine has some anti-inflammatory actions. Furthermore, steroids seem to have a positive influence on oxidant/antioxidant imbalance that is thought to be important in the pathogenesis of COPD.