All of the following take part in the pathogenesis of macular edema in diabetic retinopathy except –: (A) Retinal pigment epithelium dysfunction, (B) Oxidative stress, (C) VEGF, (D) Increased protein kinase–C
Answer is A. Etiopathogenis of diabetic retinopathy (including macular edema) 

Following factors are important in development of diabetic microangiopathy, which is responsible for the development of retinopathy :-


Activation of protein kinase C
Oxidative stress
Increased production of growth factors, amongst which Vascular endothelial growth factor A (VEGF-A is the most important). Other factors are TGF - β, PDGF, EGF and IGF