Using human retinal endothelial cells (HRECs) in culture, and the rat model of diabetic retinopathy, we have investigated the effect of re-institution of normal glycemia on epigenetic modifications of Mfn2 and Mlh1. We have also examined the effect of intervention of the reversal phase with inhibitors of Dnmts on the mitochondrial structural and genomic stability, and on the development of diabetic retinopathy. This evidence concerns the gene MFN2 and diabetic retinopathy.