[Patophysiology of diabetic retinopathy]

Diabetic retinopathy (DR) is the affection of the retina in patients with diabetes mellitus (DM). The basic causative factor is prolonged hyperglycaemia. DR is microangiopathy, ie impairment of retinal capillaries. Pathophysiology of DR is very complex and there are involved in many factors. The first and most fundamental factor is the failure blood-retinal barrier (BRB). The major mechanism causing malfunction of BRB are advanced glycation end-products (AGE). In the failure of the inner BRB are involved losses of endothelial cells in capillaries, together with the losses of pericytes. A very important role in the failure of BRB plays too increased adhesivity of leukocytes. Further important role play also AGE and their receptor RAGE. They stimulate cascade of pathological processes damaging BRB. The second important factors in the pathophysiology of DR are vasoactive factors. The most important is vascular endothelial growth factor (VEGF), further than protein kinase C (PKC), histamine, angiotensin II, matrix metaloproteinases. The third important factor in the pathophysiology of DR is the vitreoretinal interface. There plays important role detachment of posterior vitreous, cortical vitreous, internal limiting membrane.