role of the vitreal levels of angiotensin II and vascular endothelial growth factor in the pathogenesis of some retinal disorders

ABSTRACT

To investigate whether Angiotensin II [AII] plays a role in the development of proliferative diabetic retinopathy [PDR] and diabetic macular edema [DME] in combination with vascular endothelial growth factor [VEGF], which is considered to be the most potent factor in promoting angiogenesis. Therefore, we investigated the relation between the plasma and vitreal levels of AII and VEOF in patients with DME and PDR. Plasma and vitreous samples were obtained simultaneously from 6 subjects with DME and 14 subjects with PDR compared to 8 subjects with macular hole as controls. The VEGF levels in vitreous fluid and plasma were determined by a competitive enzyme immunoassay [EIA], while AII levels were measured by a competitive RIA. The vitreous fluid levels of VEGF and All were significantly higher in DME and PDR than in macular hole group [p < 0.05], [p < 0.01], [p < 0.001], [p < 0.001] respectively. VEGF and AII in vitreous of subjects with DME and PDR were also significantly higher than plasma levels p < 0.001]. The vitreous level of AII was significantly positively correlated with that of VEGF in the PDR and DME groups. We found that the levels of AII and VEGF were significantly elevated in vitreous of patients with DME and PDR. Our results suggest that there is a significant relation between VEGF and All, and they are related to increase vascular permeability in DME and PDR