Growth factor regulation of neutrophil-endothelial cell interactions

The effects of the angiogenic factors basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF) on human polymorphonuclear leukocyte (PMNL)-endothelial cell adhesion and transendothelial migration (TEM) were investigated. Stimulation of human umbilical vein endothelial cells by VEGF or bFGF for 18 h up-regulated intercellular adhesion molecule 1 and vascular cell adhesion molecule 1 expression and significantly increased PMNL adhesion and TEM in response to complement fragment 5a (C5a) or interleukin (IL)-8. In contrast, continued exposure to bFGF (24 h-6 days) down-regulated basal and IL-1- or tumor necrosis factor (TNF)-induced intercellular adhesion molecule 1, vascular cell adhesion molecule 1, and E-selectin expression as well as PMNL adhesion and TEM. These effects could be reversed by introduction of high concentrations of TNF-α, C5a, or IL-8. None of these inhibitory effects was observed with VEGF. The acute effects of bFGF and VEGF may facilitate PMNL emigration during acute inflammation, but continued bFGF production may have anti-inflammatory actions during chronic inflammation, angiogenesis, and tumor defense by inhibition of endothelial activation for leukocyte recruitment.