Exploring the various aspects of the pathological role of vascular endothelial growth factor (VEGF) in diabetic retinopathy

Diabetic retinopathy, a sight-threatening microvascular complication of diabetes mellitus, is initiated by retinal endothelial dysfunction and succeeded by various pathological events, eventually resulting in vision-loss. These events are regulated by numerous mediators, including vascular endothelial growth factor (VEGF), which induces the progression of various events characterizing diabetic retinopathy, such as neovascularization and macular edema. VEGF is physiologically required for regulating proliferation and assembling of endothelial cells, during vasculogenesis, as well as for their maintenance and survival throughout the lifetime of blood vessels. However, various pathological conditions are induced in the body during diabetes (such as ischemia, oxidative stress and overactivation of protein kinase C), which upregulate the expression of VEGF, thereby deviating it from its physiological role and leading to various pathological demonstrations such as angiogenesis, increased permeability of endothelium, decreased inhibition of pro-apoptotic proteins and activation of various other inflammatory mediators. Such events disrupt vascular homeostasis and play key roles in the pathophysiology of diabetic retinopathy. Hence, acknowledging various VEGF-mediated pathways helps in understanding the deeper aspects related to progression of this disorder. Targeting and inhibiting VEGF-mediated disease progression might provide an effective alternative therapy and hence prove beneficial in the treatment of diabetic retinopathy.