Different plasma levels of vascular endothelial growth factor and nitric oxide between patients with choroidal and retinal neovascularization.

Because the blood flow is much more intense in the choroid than in the retina, it is interesting to explore whether choroidal neovascularization (CNV) is more influenced by plasma angiogenic factors than retinal neovascularization. The aim of this study was 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 in those with retinal neovascularization due to proliferative diabetic retinopathy (PDR). Seventy-seven subjects with AMD, 22 with PDR, and 42 nondiabetic, non-AMD controls were enrolled in this comparative case series. AMD subjects were classified into three groups: dry type (dry AMD, n = 17), wet type with active CNV (CNV/AMD, n = 42), and disciform scar due to advanced wet AMD (scar/AMD, n = 18). Plasma VEGF and NO levels of each subject were measured with enzyme-linked immunosorbent assay and chemiluminescence, respectively. Plasma VEGF level in CNV/AMD (median 256.0 pg/ml, interquartile range 146.4-375.3 pg/ml) was significantly higher than in PDR (124.8 pg/ml, 75.7-215.3 pg/ml; p = 0.004) and controls (120.3 pg/ml, 82.8-168.2 pg/ml, p =0.001). CNV/AMD also had the highest VEGF level among the AMD subgroups. Plasma NO level was significantly elevated in PDR (137.4 microM, 63.7-240.1 microM) when compared with CNV/AMD (71.8 microM, 42.4-113.3 microM; p = 0.004) and controls (62.6 microM, 39.0-114.9 microM; p = 0.002). There was no significant difference in NO levels among the AMD subgroups. No significant correlation between VEGF and NO levels was noted. These findings indicate that both circulating VEGF and NO may play different roles in the pathogenesis of retinal neovascularization and CNV.