Oxidative stress and lung function profiles of male smokers free from COPD compared to those with COPD: A case-control study

Abstract

Background: The mechanisms of smoking tobacco leading to chronic obstructive pulmonary disease (COPD) are beginning to be understood. However, conclusions about the role of blood or lung oxidative stress
markers were disparate.
Aims: To investigate the oxidative stress in blood or lung associated with tobacco smoke and to evaluate its effect on pulmonary function data and its relation with physical activity.
Methods: It is a case-control study. Fifty-four male-smokers of more than five pack-years (PY) and aged 4060 years were included (29 Non-COPD, 16 COPD). Physical activity score was determined. Blood sample levels of malondialdehyde (MDA), protein-cys-SH (PSH), and Glutathione (GSH) were measured. Fractional exhaled nitric oxide (FeNO) and plethysmographic measurements were performed. Correlation coefficients (r) evaluated the association between oxidative stress markers and independent variables (plethysmographic data and physical activity score).
Results: Non-COPD (4896 years) and COPD (4995 years) groups had  similar tobacco consumption patterns, that is, 27914 PY versus 30919 PY, respectively. Compared to the Non-COPD group, the COPD group had significantly lower levels of GSH and PSH, that is, mean9SE were 4096 versus 2595 mg/mL and 54910 versus 2695 mg/g of hemoglobin,  respectively. However, MDA level and FeNO values were similar. In the COPD group, none of the oxidative stress markers was significantly  correlated with plethysmographic data or physical activity score. In the Non-COPD group, GSH was significantly correlated with physical activity score (r0.47) and PSH was significantly correlated with total lung capacity (TLC) (r0.50), residual volume (r0.41), and physical activity score (r0.62). FeNO was significantly correlated with TLC of the COPD group (r0.48).
Conclusion: Compared to the Non-COPD group, the COPD group had a marked decrease in blood antioxidant markers (GSH and PSH) but similar blood oxidant (MDA) or lung (FeNO) burden.

Keywords: inflammation; lung disease; spirometry; tobacco; sedentarily; stress oxidant