Purpose: Vascular endothelial growth factor (VEGF) is upregulated by hypoxia and is a major stimulatory factor for retinal neovascularization in ischemic retinopathies such as diabetic retinopathy. This study sought to determine if VEGF is a stimulatory factor in a murine model of choroidal neovascularization (CNV).
Methods: Mice with laser-induced ruptures in Bruch's membrane were treated with vehicle alone; a drug that inhibits both VEGF and platelet-derived growth factor (PDGF) receptor kinases; a drug that inhibits PDGF, but not VEGF receptor kinase; or genistein, a nonspecific kinase inhibitor. After two weeks, CNV was quantified and compared.
Results: Blockade of phosphorylation by VEGF and PDGF receptors caused dramatic, almost complete inhibition of CNV. Genistein also had an inhibitory effect, but less so than the VEGF/PDGF receptor blocker. Blockade of phosphorylation by PDGF receptors, but not VEGF receptors, had no significant effect on CNV.
Conclusions: These data and our previous study, which demonstrated that a kinase inhibitor that blocks VEGF and PDGF receptors and several isoforms of protein kinase C causing dramatic inhibition of CNV, suggest that VEGF signaling plays a critical role in the development of CNV in this model. If safety is established, the effect of inhibiting VEGF receptor kinase activity should be investigated in patients with CNV.