Relationship Between Vascular Endothelial Growth Factor and Angiopoietin-2 in Asthmatics Before and After Inhaled Beclomethasone Therapy

Abstract

Vascular endothelial growth factor (VEGF) and Angiopoietin-2 (Ang-2) play complementary roles in the process of vascular remodeling. Therefore, this study was designed to examine an interaction between VEGF and Ang-2 in asthmatic airways. VEGF, Ang-2, and hepatocyte growth factor (HGF) levels in induced sputum obtained from 17 asthmatic patients and 10 normal control subjects were examined. Eight weeks of inhaled beclomethasone dipropionate (BDP) therapy (800 µg/day) was administered to all asthmatic patients, and sputum induction was repeated. VEGF, Ang-2, and HGF levels in induced sputum were significantly higher in asthmatic patients than in control subjects. Ang-2 levels were significantly correlated with VEGF levels but not with HGF levels. We also found that there was a significant correlation between airway vascular permeability index and VEGF levels but not HGF levels. In addition, VEGF/Ang-2 ratio in asthmatic patients was significantly higher than that in control subjects, and it was significantly correlated with airway vascular permeability index. After inhaled BDP therapy, VEGF levels were significantly decreased, but Ang-2 levels did not change. Therefore, VEGF/Ang-2 ratio after BDP therapy was markedly decreased to the same level as in the control subjects. Our findings suggest that interaction between VEGF and Ang-2 in asthmatic airways may exist and that high VEGF/Ang-2 ratio may be responsible for increased airway microvascular permeability. In addition, inhaled glucocorticoids therapy may reduce airway vascular permeability and remodeling via VEGF/Ang-2-dependent mechanism.