Quantification of Aqueous and Vitreous VEGF Following Branch, Hemi– and Central Retinal Vein Occlusions

Abstract

Abstract: : Purpose:To determine vascular endothelial growth factor (VEGF) levels in the aqueous and/or vitreous compartments in the eye after branch, hemi–, and central retinal vein occlusions (BRVO, CRVO). Methods:Seven patients consented to have aqueous and/or vitreous samples taken during surgical interventions for treatment of retinal vein occlusions (radial optic neurotomy for CRVO (2), intravitreal triamcinolone for HRVO (1), arterio–venous sheathotomy for BRVO (4)). Two patients without vein occlusions served as controls. VEGF levels were quantified using ELISA. Results:Time from vein occlusion symptoms to surgery ranged from 2 weeks to 6 months. Mean aqueous VEGF levels were 265pg/mL (range 0–552) for BRVO and 1766pg/mL (range 1402–2130) for CRVO. Mean vitreous VEGF levels were 809 pg/mL for BRVO (range 11–2177), 1689 pg/mL (range 997–2380) for CRVO, and 2039 pg/mL for the one patient with HRVO. The mean vitreous level for control subjects was 138 pg/mL. There was a direct positive relationship between duration from patient symptoms to sampling and VEGF levels. As a group (i.e. all types of RVO included), the mean aqueous and vitreous levels for those sampled within 5 weeks of symptoms were 1008 pg/mL and 1869 pg/mL respectively. Conversely, the mean aqueous and vitreous levels for those sampled after 5 weeks of symptoms were 522 pg/mL and 391 pg/mL respectively. Conclusions:VEGF levels are elevated in the vitreous and aqueous after all types of retinal vein occlusions. The aqueous levels after BRVO are much lower than both BRVO vitreous levels and CRVO aqueous levels. This finding may partially explain the rarity of clinically noted neovascularization of the iris following BRVO. Additionally, the findings also correspond to the more frequent development of neovascularization of the retina following BRVO and neovascularization of the iris following CRVO.

Keywords: vascular occlusion/vascular occlusive disease • retinal neovascularization • vitreoretinal surgery