Abstract
Aims: Chronic Obstructive Pulmonary Disease (COPD) is the fourh leading cause of death worldwide. Its prevalence is increasing in the world. Tobacco smoking is the major risk factor for COPD. Oxidant-antioxidant and protease-antiprotease imbalance is the major hallmarks for the pathogenesis of COPD. The present study was planned to assess the correlation between markers of airflow obstruction with the serum level of neutrophil elastase, nitric oxide and superoxide dismutase in COPD patients.

Study design: Case Control Study. Place and Duration of Study: Department of Biochemistry, B.J.Govt. Medical College, Pune.[Maharashtra],The study period was in between Feb.2012 to Dec. 2013. Methodology: Study comprised of 60 stable COPD patients and 60 healthy controls. COPD patients were selected as per the GOLD (Global Initiative for Obstructive Lung Disease) criteria with of aged between 40 to 75 yrs. Each subject undergone through the pulmonary function test by spirometry prior to enter in the study and predicted values of FEV1, FVC and FEV1/FVC were measured. Serum level of neutrophil elastase (NE) was analyzed using commercial available ELISA kits while serum level of nitric oxide and superoxide dismutase were measured by spectrophotometric methods. Statistical analysis was done by using SPSS software 17 version.

Results: In our study we observed significantly increased levels of serum neutrophil elastase and nitric oxide and decreased level of enzymatic antioxidant superoxide dismutase (SOD) in COPD patients as compared to healthy controls. We found significant strong inverse correlation between neutrophil elastase(r = -0.604, P < 0.0001) and nitric oxide(r = -0.565, P < 0.0001) with FEV1% predicted and positive correlation between superoxide dismutase and FEV1% predicted (r = +0.394, P < 0.001) in COPD patients.

Conclusion: The present study demonstrates that the level of nitric oxide, superoxide dismutase and neutrophil elastase in serum might have played role in oxidative stress and inflammation in COPD patients. Hence, it can be concluded that the measurement of these biomarkers in serum may provide a good approach to assess the severity of the disease in COPD patients.