VASCULAR ENDOTHELIAL GROWTH-FACTOR UP-REGULATION IN HUMAN CENTRAL RETINAL VEIN OCCLUSION

Background and Objective: Vascular endothelial growth factor (VEGF), a key mediator of intraocular neovascularization, is triggered by hypox ia and has been shown in the eyes of animal models of central retinal vein occlusion (CRVO), However, there is little information on CRVO in humans, in particular, the identity of VEGF-producing cells. Study De sign: The study design was molecular localization of the site of VEGF production in the eyes of patients with CRVO. Participants: Ten formal dehyde solution-fixed and paraffin-embedded eyes removed surgically fr om patients with CRVO and neovascular glaucoma were studied, Five eyes with uveal melanoma and no neovascularization sewed as control specim ens. Methods: Thin whole-eye sections were hybridized in situ with a V EGF-specific probe to identify cells producing VEGF messenger RNA (mRN A). Results: All ten eyes with CRVO showed evidence of intraretinal ex pression of VEGF mRNA. In all eyes, the inner nuclear layer showed VEG F-upregulated expression, Upregulation of VEGF mRNA was identified in four eyes in the ganglion cell layer and in two eyes with retinal deta chment in the outer nuclear layer as well. Conclusions: The population of VEGF-producing retinal cells in each eye is likely to represent ce lls residing in ischemic regions of the retina, Hypoxia-induced VEGF i s, most likely, the linking factor between retinal ischemia and iris a nd retinal neovascularization in CRVO.