Angiogenesis Factors in Diabetic Retinopathy: Effects of laser photocoagulation and renin– angiotensin system blockade.

Abstract

Abstract: : Purpose: To assess the effect of panretinal laser photocoagulation and renin–angiotensin blockade with angiotensin II receptor antagonists on plasma vascular endothelial growth factor, Angiopoietin2 and Tie2. Methods: A prospective interventional study was carried out on 19 patients with active proliferative retinopathy and 28 patients with nonproliferative or preproliferative retinopathy. The diabetic retinopathy was graded according to the worst affected eye by masked expert observers using retinal photographs. They were divided into 2 study subgroups based on retinopathy: Subgroup A or active proliferative retinopathy and subgroup B or nonproliferative/ preproliferative retinopathy. Subgroup A: Intervention consisted of panretinal laser photocoagulation according to ETDRS guidelines. The exclusion criteria were a history of panretinal laser photocoagulation in the previous 12 months and failure to complete at least 6 weeks post–treatment follow–up. Subgroup B: Intervention consisted of treatment with Tab Eprosartan, an angiotensin II receptor antagonist. The exclusion criteria included ongoing treatment with an angiotensin II receptor antagonist at start of study and failure to complete at least 5 weeks of drug therapy. Plasma vascular endothelial growth factor, Angiopoietin2 and Tie2 were measured at baseline and post–intervention in each subgroup. Results: Plasma vascular endothelial growth factor, Angiopoietin2 and Tie2 levels were not significantly different in either group pre or post intervention. Conclusion: The interaction of angiogenesis factors in the pathogenesis of diabetic retinopathy is complex. In this study we were unable to demonstrate any significant differences between the pre and post intervention plasma VEGF, Angiopoietin2 and Tie2 levels in either subgroup.

Keywords: diabetic retinopathy