Background Pigment epithelium-derived factor(PEDF)is expressed in several normal organs and identified as aninhibitor of neovascularization.In the present study,we investigated the effect of PEDF in an in vitro model of ocularchoroidal neovascularization.Methods Microdissection was used to isolate the human choroidal endothelial cells(CECs),followed by the use ofsuperparamagnetic beads(Dynabeads)coated with the CD31 antibody,which selectively binds to the endothelial cellsurface.The mitogenic and motogenic effects of vascular endothelial growth factor(VEGF)on cultured choroidal capillaryendothelial cells were examined in the presence or absence of PEDF(1,10,100,and 1000 ng/ml)using cell counts andmigration assays.Results Cells bound to the beads were isolated using a magnetic particle concentrator and they were successfullycultured and characterized to be endothelial cells that possessed greater than 95% immunoreactivity to von Willebrandfactor.PEDF suppressed the proliferation and migration of VEGF-induced choroidal capillary endothelial cells.However,the concentration of PEDF which we used has little effect on normal CECs.Conclusions PEDF played an important role on the growth and migration of VEGF-stimulated choroidal endothelial cellThese findings suggest that PEDF may be an effective approach to the treatment of choroidal neovascular disorders.Chin Med J 2007;120(17):1534-1538 Background Pigment epithelium-derived factor (PEDF) is expressed in several normal organs and identified as an inhibitor of neovascularization. In the present study, we investigated the effect of PEDF in an in vitro model of ocularchoroidal neovascularization. Methods Microdissection was used to isolate the human followed by the use of superparamagnetic beads (Dynabeads) coated with the CD31 antibody, which selectively binds to the endothelial cells surface. The mitogenic and motogenic effects of vascular endothelial growth factor (VEGF) on cultured choroidal capillary endothelial cells in the presence or absence of PEDF (1, 10, 100 and 1000 ng / ml) using cell counts and migration assay. Results Cells bound to the beads were isolated using a magnetic particle concentrator and they were successfully cultured and and characterized to be endothelial cells that possessed greater than 95% immunoreactivity to von Willebrand factor. PEDF suppressed the proliferation and mig Of the VEGF-induced choroidal capillary endothelial cells. However, the concentration of PEDF which we used has little effect on normal CECs. Conclusions PEDF played an important role on the growth and migration of VEGF-stimulated choroidal endothelial cells These findings suggest that PEDF may be an effective approach to the treatment of choroidal neovascular disorders. Chin Med J 2007; 120 (17): 1534-1538