Abstract
Purpose: :
To determine proliferation and migration of retinal microvascular endothelial cells in the presence of diabetic and non-diabetic vitreous and to examine how VEGF and bFGF could contribute to the angiogenesis-related activity of vitreous. A further goal of this study was to find out whether vitreous matrix components affect the pro-angiogenic activity of retinal microvascular endothelial cells.
Methods: :
Undiluted vitreous fluid samples (0.3-0.6 ml) were obtained from patients with proliferative diabetic retinopathy during pars plana vitrectomy. Vitreous from patients undergoing bevacizumab (Avastin) treatment and control samples from pucker patients were also included. Human VEGF and bFGF concentrations were determined by enzyme-linked immunosorbent assay. Retinal endothelial cell proliferation rates were determined by BrdU incorporation assays and endothelial cell migration was determined using a modified Boyden chamber assay.
Results: :
Exposure of endothelial cells to diabetic vitreous increased their proliferation and migration rates when compared to non-diabetic vitreous. However, vitreous from diabetic patients followingAvastin treatment or vitreous samples pre-treated with anti-VEGF or anti-bFGF antibodies in vitro demonstrated reduced angiogenic activity. Moreover, pre-treatment of endothelial cells with fibronectin (a matrix component which is highly expressed in diabetic vitreous) increased their proliferation and migration.
Conclusions: :
Diabetic vitreous has shown an increased angiogenic activity on retinal endothelial cells in comparison to the vitreous from non-diabetic patients. Although VEGF and bFGF have been shown to be important factors to promote new vessel formation, vitreous matrix components like fibronectin could also contribute to the pro-angiogenic effects mediated by diabetic vitreous.
Keywords: diabetic retinopathy • neovascularization • vitreous