Relevance of copper/zinc ratio and its association with redox status in chronic obstructive pulmonary disease

Background: Chronic obstructive pulmonary disease is a progressive and persistent inflammatory condition associated with significant morbidity and mortality. Increased oxidative stress amongst others, plays an important role in the pathogenesis of this disease. The objective of the present study was to conduct a preliminary yet comprehensive examination of metal exposure specifically copper and zinc levels and their association with overall oxidative stress in COPD. Methods: A cross sectional study was carried out in a tertiary care hospital in South India. Two groups were included in the study. One group with 20 COPD patients and the other group of 20 healthy controls. Plasma samples were obtained from both the groups and serum levels of copper and zinc were studied by atomic absorption spectrometry. Cu/Zn ratio obtained from the results was further correlated with oxidative stress index calculated from total oxidant status and total antioxidant status in COPD with respect to controls. Results: The copper levels were significantly higher and the zinc levels lower in the COPD group as compared to the control group. The copper/zinc ratio was higher in COPD as compared to control population. The correlation between Cu/Zn ratio and oxidative stress index showed a positive correlation with a regression coefficient of 0.7. Conclusions: The study throws light on the trace element imbalance in COPD and how these could induce oxidative stress, contributing to persistent inflammation in COPD. In the clinical perspective, monitoring Cu/Zn ratio in COPD patients may lead to better risk mitigation and thereby better therapeutic management of the disease.