Abstract
Purpose: :
It has been reported that Pigment Epithelium–Derived Factor (PEDF) is a potent anti–angiogenic factor, whose concentration in the vitreous is reported to be around 1500 ng/ml. However, the precise mechanisms are not clarified to date. Therefore, we tried to examine how PEDF has suppressive effects on neovascularization by way of in vitro assays.
Methods: :
Bovine retinal microvascular endothelial cells (BRECs) and human umbilical vein endothelial cells (HUVECs) were used for in vitro assays. To estimate the effect of PEDF on the proliferation, migration and tube formation by endothelial cells, thymidine uptake, boyden chamber assay and tube formation assay were performed. Moreover, to investigate whether PEDF suppresses the expression of vascular endothelial growth factor (VEGF) or its receptor (VEGFR2) and inhibits VEGF–dependent phosphorylation of VEGFR2 or p44/42 MAP kinase, Northern and Western blot analyses were performed. SU5416 was used as a selective inhibitor of VEGFR2 phosphorylation.
Results: :
PEDF, up to a concentration of 1500 ng/ml, showed no significant suppressive effect on the cellular proliferation, migration and tube formation by endothelial cells. Furthermore, no obvious inhibitory effects on the expression of VEGF or VEGF–induced phosphorylation of VEGFR2 and p44/42MAP kinases were detected.
Conclusions: :
These results indicated that PEDF, at least up to a concentration of 1500 ng/ml, has no significant anti–angiogenic effect on vascular endothelial cells directly.
Keywords: retinal neovascularization