Neutrophil Activation in Severe, Early-Onset COPD Patients versus Healthy Non-Smoker Subjects in vitro: Effects of Antioxidant Therapy

Background: Neutrophils and oxidative stress have been implicated in the pathogenesis of COPD. Severe, early-onset COPD is characterized by a rapid decline in the lung function at an early age; however, nothing is known about neutrophil activation in COPD patients. Objectives: The aim of this study was to evaluate peripheral blood neutrophil activation in severe, early-onset COPD patients versus healthy nonsmokers and the effect of N-acetyl-L-cysteine (NAC) on neutrophil activation in vitro. Methods: Neutrophils were isolated from 15 severe, early-onset COPD patients and 15 age-matched healthy subjects and stimulated with N-formyl-Met-Leu-Phe (fMLP) in the presence or absence of NAC (10 mu M to 10 m M). Neutrophil chemotaxis, elastase release, reactive oxygen species (ROS), intracellular thiols and apoptosis were measured by Boyden chamber, spectrofluorometry, CMFDA and H2DCF-DA dyes and by annexin V-FITC, respectively. Results: Chemotaxis of peripheral blood neutrophils from COPD patients in response to fMLP was 30% more increased than that observed in healthy subjects. Elastase release in response to fMLP was 2-fold higher in neutrophils from COPD patients versus healthy subjects. Intracellular thiol levels were 30% lower in COPD and ROS was approximately 30% higher in COPD versus healthy neutrophils. Spontaneous apoptosis showed no differences in both groups of patients and fMLP-induced apoptosis was higher in COPD. Pre-treatment with the antioxidant NAC effectively attenuated neutrophil chemotaxis, elastase release and ROS as well as effectively increased thiol levels in COPD. Conclusions: Neutrophils in severe, early-onset COPD patients are highly activated and this is alleviated by NAC in vitro. Copyright (C) 2011 S. Karger AG, Basel