Angiopoietin-1 reduces VEGF-stimulated leukocyte adhesion to endothelial cells by reducing ICAM-1, VCAM-1, and E-selectin expression

Vascular endothelial growth factor (VEGF) and angiopoietin-1 (Ang1) are pot ent vasculogenic and angiogenic factors that hold promise as a means to pro duce therapeutic vascularization and angiogenesis. However, VEGF also acts as a proinflammatory cytokine by inducing adhesion molecules that bind leuk ocytes; to endothelial cells, an initial and essential step toward inflamma tion. In the present study, we used human umbilical vascular endothelial ce lls (HUVECs) to examine the effect of Ang1 on VEGF-induced expression of th ree adhesion molecules: intercellular adhesion molecule-1 (ICAM-1), vascula r cell adhesion molecule-1 (VCAM-1), and E-selectin. Interestingly, Ana1 su ppressed VEGF-induced expression of these adhesion molecules. Furthermore, Angl reduced VEGF-induced leukocyte adhesion to HUVECs. These results demon strate that Ang1 counteracts VEGF-induced inflammation by reducing VEGF-ind uced endothetial adhesiveness.