Anti-VEGF Treatment for Diabetic Retinopathy

Vascular endothelial growth factor (VEGF) has a number of interesting properties. It has been shown to stimulate angiogenesis and induce vascular permeability, in addition to its proinflammatory and neuroprotectve characteristics. VEGF degrades the basement membrane of endothelial cells, which in turn causes the endothelial cells to change shape and proliferate. It is 50, 000 times more potent than histamine for inducing vascular permeability, and vascular permeability may be an antecedent to neovascularization. VEGF is essential for a number of physiological processes, including normal embryonic development and the female reproductive cycle. VEGF is present in the brain, kidney, and GI mucosa.

In terms of vision, VEGF is present in healthy eyes and elevated in both experimental models of diabetes and patients with diabetic retinopathy. VEGF is implicated in age-related macular degeneration, retinal vein occlusion, corneal and iris neovascularization, and diabetic retinopathy. The anti-VEGF agent pregaptanib has been studied in diabetic macular edema. Results have shown that pregaptanib treatment improves visual acuity, decreases retinal thickness, reduces the need for focal laser photocoagulation, and may induce regression of retinal neovascularization. This phase 2 study shows promise, and additional work is being done to test the efficacy of anti-VEGF therapies in diabetes.