All of the following take part in the pathogenesis of macular edema in diabetic retinopathy except –
Retinal pigment epithelium dysfunction
Oxidative stress
VEGF
Increased protein kinase–C
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