Serum angiopoietin-2 levels are elevated during acute exacerbations of COPD

Background and objective: Recently, angiopoietin‐2 (Ang‐2) was identified as a ligand of the endothelial receptor tyrosine kinase, Tie‐2. Ang‐2 is an angiopoietin‐1 antagonist that plays a role in vascular destabilization and remodelling, which may increase in some diseases. However, serum Ang‐2 levels have not been evaluated in patients with COPD. In this study, we examined serum Ang‐2 concentrations in patients experiencing COPD exacerbations and in patients with stable COPD. Methods: Serum samples were obtained from 49 patients experiencing COPD exacerbations, 22 patients with stable COPD and 18 healthy control subjects. Serum Ang‐2 concentrations were measured by ELISA. Results: Serum Ang‐2 concentrations were significantly higher in patients with acute exacerbations of COPD than in those with stable COPD or control subjects, and were significantly positively correlated with serum CRP levels but inversely correlated with PaO₂ in patients with exacerbations. In addition, Ang‐2 levels decreased significantly after clinical recovery from the acute exacerbation. Conclusions: Serum Ang‐2 levels are significantly elevated during acute exacerbations of COPD, as compared with stable COPD.