Retinal microvessels, the site of histopathology characteristic of diabetic retinopathy, from diabetic rats and from human donors with documented diabetic retinopathy, also showed a significant increase in the mRNA levels of Drp1 and Fis1 and GTPase activity of Drp1, compared to their respective controls (age-matched normal rats and nondiabetic donors). Here, FIS1 is linked to diabetic retinopathy.