Abstract
Abstract: :
Purpose: Since the blood flow is much ampler in choroid than in retina, choroidal neovascularization (CNV) is hypothesized to be more influenced by plasma angiogenic factors than retinal NV. This study is aimed to investigate plasma profiles of vascular endothelial growth factor (VEGF) and nitric oxide (NO) in patients with CNV due to age–related macular degeneration (AMD) and those with retinal NV due to proliferative diabetic retinopathy (PDR). Methods:Blood samples were obtained from 77 subjects with AMD, 22 with PDR, and 42 non–diabetic, non–AMD controls. AMD subjects were classified into 3 groups: dry type (n=17), wet type with active CNV (n=42), and disciform scar due to advanced wet AMD (n=18). VEGF levels were determined by using enzyme–linked immunosorbent assay (ELISA) and NO levels by chemilluminescence assay. Results: Wet AMD subjects with active CNV had significantly raised plasma VEGF level (263.8±24.7 pg/ml, mean±SEM ) in comparison with PDR subjects (147.0±16.4 pg/ml, P=0.004), dry AMD subjects (122.1±17.7 pg/ml, P=0.001) and controls (136.3±12.8 pg/ml, P<0.001). The plasma level of NO was significantly lower in wet AMD subjects with active CNV (95.2±12.2µM) when compared with PDR subjects (160.6±22.8µM, P=0.004). There was no significant difference in plasma levels of both VEGF and NO between AMD subjects with active CNV and with disciform scar. No significant correlation between VEGF and NO levels was found in any groups. Conclusions: Plasma levels of VEGF and NO are significantly different between patients with CNV due to AMD and those with retinal NV due to PDR. Increase in plasma VEGF level, not NO, is associated with wet type AMD, regardless of the activity of CNV. Our results suggest that overexpression of VEGF in the choriocapillaris may predispose to the development of CNV in AMD subjects with defects of Bruch’s membrane.
Keywords: age–related macular degeneration • choroid: neovascularization • retinal neovascularization