Angiopoietin-1 inhibits endothelial permeability, neutrophil adherence and IL-8 production.

1 Angiopoietin-1 (Ang1) is an angiogenic growth factor that binds to the Tie2 receptor on vascular endothelium, promoting blood vessel maturation and integrity. In the present study, we have investigated whether Ang1 also possesses anti-inflammatory properties by determining its effects on endothelial barrier function, neutrophil (PMN) adherence to endothelial cells (EC) and production of the PMN chemotactic factor interleukin-8 (IL-8). 2 Pretreatment of endothelial monolayers with Ang1 attenuated the permeability increase induced by thrombin in both lung microvascular cells and a human endothelial cell line.