Diyabetik Retinopati ve Nitrik Oksit

One of the most important cause of blindness in developed or developing countries is diabetic retinopathy, of which pathogenesis has not been yet clarified exactly. Understanding of pathogenesis of DRP can cause better management of this disease. Vascular damage is leading pathology in diabetic retinopathy. There is some proof that endothelin has important role in maintenance of vascular tonus and structure. Nitric oxide (NO) is one of the most important vasoactive mediators derived from endothelium. Nitric oxide is multifunctional molecule having key role on the anti-proliferative regulation of vascular smooth muscle cells. It has also been suggested that nitric oxide can play a role in the pathogenesis of diabetic retinopathy.There are three nitric oxide synthase (NOS) isoenzymes producing NO. Out of them, the isoenzyme present essentially in vascular endothelium is called as endothelialNOS (eNOS) and needed to protect endothelial functions. It has been reported that NO can control cellular growth and play role in the retinal pathologies due to proliferative retinal diseases. From this respect, eNOS appears to be an interesting molecule in the identification of microvascular complications of diabetes. Various polymorphisms have also been identified in the eNOS gene. The T-786C polymorphism located in promoter region of eNOS gene, 27-bp duplication in intron 4 region and Glu298Asp in exon 7 have been attracting attention. Defective retinal eNOS expression related to its polymorphisms may contribute to the development of macular edema. Differences among the studies may demonstrate that a relationship between diabetic retinopathy and eNOS gene polymorphism can vary due to geographic and ethnic differences. Importance of NO and relevant gene polymorphisms in the pathogenesis of diabetic retinopathy has been reviewed in this article