Functional Analysis of Platelet-Activating Factor in the Retinal Pigment Epithelial Cells and Choroidal Endothelial Cells

Purpose: To investigate the function of platelet-activating factor (PAF) in cultured retinal pigment epithelial (RPE) and choroidal endothelial (CE) cells. Methods: The in vitro and in vivo expression of PAF-receptors (PAF-R) on both these cells was determined. The production of PAF by RPE cells was also determined. The effect of PAF on the proliferation, migration, permeability, and apoptosis of CE cells was examined, and the modulation of PAF on the VEGF level in RPE cells was assessed. Results: PAF-R was present in both types of cells in vitro, as well as in RPE and choroid in vivo. Cultured RPE cells synthesized PAF. PAF stimulated CE cell migration and permeability but not the proliferation. PAF also increased the VEGF level in RPE cells. Conclusions: Similar to VEGF, PAF stimulates CE cell migration and permeability. It also up regulates VEGF level in RPE cells. PAF may be involved in the pathogenesis of choroidal neovascularization.