Comparison of Serum Osteopontin Levels in Patients with Stable and Chronic Obstructive Pulmonary Disease and Exacerbation

Abstract

Methods: Serum samples were obtained from 22 healthy control subjects, 18 stable COPD patients, and 15 COPD with exacerbation patients. Serum concentrations of osteopontin were measured by the ELISA method. Results: Serum levels of osteopontin were higher in patients with acute exacerbation than with stable COPD and in healthy control subjects (62.4±51.9 ng/mL, 36.9±11.1 ng/mL, 30±11 ng/mL, test for trend p=0.003). In the patients with COPD exacerbation, the osteopontin levels when the patient was discharged from the hospital tended to decrease compared to those at admission (45±52.1 ng/mL, 62.4±51.9 ng/mL, p=0.160). Osteopontin levels significantly increased according to patient factors, including never-smoker, ex-smoker and current smoker (23±5.7 ng/mL, 35.5±17.6 ng/mL, 58.6±47.8 ng/mL, test for trend p=0.006). Also, osteopontin levels showed a significantly negative correlation with forced expiratory volume in one second (FEV 1%) predicted in healthy controls and stable COPD patients (r=−0.389; p=0.013). C-reactive protein (CRP) was positively correlated with osteopontin levels in patients with COPD exacerbation (r=0.775; p=0.002). Conclusion: The serum levels of osteopontin increased in patients with COPD exacerbation and tended to decrease after clinical improvement. These results suggest the possible role of osteopontin as a biomarker of acute exacerbation of COPD.