Therapeutics
New trends and therapeutic approaches for the management of diabetic retinopathy
Diabetes mellitus is a growing epidemic that has become a global public health problem. The long-term complications of diabetes include retinopathy, the leading cause of blindness and visual impairment in adults. Diabetic retinopathy correlates with the duration of diabetes. Improved medical care of diabetic patients, and therefore increased life expectancy, will result in more instances of diabetes-induced blindness. Several innovative therapeutic approaches address the unmet need to prevent and treat this debilitating consequence of diabetes.
D
iabetes mellitus is a global and rising prob- lem, with an estimated 220 million people worldwide currently affected. The diabetic epidemic will account for 300 million people suf- fering from diabetes in 2025, according to the World Health Organization. Diabetic retinopathy (DR) is a common microvascular complication of diabetes and a leading cause of blindness. After 15 years of diabetes, approximately 2% of people become blind, and about 10% develop severe visu- al impairment1. Forms of diabetic retinopathy include non-proliferative and proliferative diabetic retinopathy. Non-proliferative diabetic retinopathy (NPDR) is associated at early stages with retinal capillary occlusion, pericyte ghosts, capillary cell death, leukostasis, aneurysms, microvascular leak- age, haemorrhage and to some extent neuronal cell death. This results in avascular hypoxic areas that trigger, through the release of hypoxia-inducible factor 1-a (HIF-1a) and vascular endothelial
Drug Discovery World Summer 2010
growth factor (VEGF), retinal neovascularisation, a hallmark of proliferative diabetic retinopathy (PDR). Thus, PDR consists in the proliferative growth and formation of new blood vessels that develop from the inner retinal circulation. These new vessels grow beyond the supporting structure of the retina and can even rupture and haemorrhage into the vitreous in response to a rise of the blood pressure. Consequently, this haemorrhage results in vision loss. The new blood vessels can also cause retinal detachments. Diabetic macular oedema (DME), manifested by the swelling of the retina due to the leakage of fluids from blood vessels into the macula (the highly pigmented spot near the centre of the retina), can occur at any stage of the disease. However, it is more frequently observed in PDR patients. Macular oedema does not cause total blindness but can lead to severe vision loss. PDR and DME account for 9% and 17% of all diag- nosed diabetic retinopathy cases, respectively2.
By Dr Didier Pruneau
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