Oxidative stress in peripheral blood leukocytes of patients with chronic obstructive pulmonary disease

Introduction. It is known that oxidative stress causes pathological changes in the tissues and organs of the human body and in many cases it can explain the disorders associated with chronic obstructive pulmonary disease (COPD).Aim. The aim of the study was to investigate the degree of oxidative stress in peripheral blood leukocytes of COPD patients.Materials and methods. We examined 23 patients with COPD of varying severity, 8 smokers without signs of bronchial obstruction and 9 healthy volunteers who had never smoked. All subjects underwent spirometry to assess lung function. The level of oxidative stress was determined using flow cytometry by adding 10 µM 2',7'-dichloro dihydrofluorescein diacetate to isolated peripheral blood leukocytes, in basal conditions and under pro-inflammatory stimulation with 0.1 ng/ml phorbol-12-myristate-13-acetate (PMA).Results. Patients with COPD demonstrated elevated levels of intracellular oxidative stress compared with controls both under basal conditions and during PMA stimulation (p<0.05). When analyzed in subgroups, stimulation led to a significant increase in oxidative stress regardless of cell type (p<0.01). Smokers tend to have elevated measured values, occupying an intermediate position between non-smokers and COPD patients. The absolute increase in the oxidative stress index was higher in the cells of COPD patients; the values of the relative increase were almost identical in the studied groups. The dynamics of oxidative stress in the cells of smokers tended to be more pronounced than in non-smokers.Conclusion. The obtained results indicate that the leukocytes of COPD patients are characterized by a higher level of intracellular oxidative stress. In addition, smoking has been found to be a factor of oxidative stress development in healthy individuals.