Novel therapeutic targets in diabetic macular edema: Beyond VEGF

The leading cause of major vision loss in diabetic persons is diabetic macular edema (DME). The hallmark feature of diabetic retinopathy is the alteration of the blood-retinal barrier (BRB). Inflammation plays a crucial role in DME with involvement of several chemokines and cytokines including vascular endothelial growth factor (VEGF). VEGF is a potent cytokine and vaso-permeability factor that has been targeted in multiple, large clinical trials. Multiple anti-VEGF drugs are widely used in the treatment of diabetic macular edema (DME) as the first line of treatment, and have been shown to be effective in vision improvement and prevention of vision loss. However, many DME patients do not show complete response to anti-VEGF drugs despite multiple intravitreal injections with these drugs. Also, the effect seems to be transient in those responders, and many patients do not show complete resolution of fluid. This article summarizes the mechanisms other than VEGF, and how these novel factors can be targeted as promising therapies of DME.