Alpha-V beta-3 and Alpha V Beta-5 Integrin Identification on Endothelial Cells of Human Eyes with Choroidal Neovascular Membranes

Abstract

Abstract: : Purpose: To investigate the presence of alpha-V beta-3 and alpha-V beta-5 intgerins on proliferating endothelial cells of choroidal neovascular membranes (CNV)associated with human age related macular degeneration (ARMD). Methods: Immunohistochemical staining was performed using paraffin embedded sections of human eyes with known CNV from ARMD patients (N=14). Anti alpha-V beta-3 and anti alpha-V beta-5 monoclonal antibody tagged with green and red fluroescein respectively were adsorbed to deparaffinized CNV tissue slides containing the extracted neovascular membranes. Antigen staining was then carried out using standard protocol. Controls consisted of deparaffinized tissues sections of normal eyes. After Immunohistochemical staining, control and study slides were examined under the microscope for differential staining. Intensity of staining was recorded by photograph. Results: Histopathological sections revealed characteristic findings suggestive of CNV, including presence of fibrovascular tissue between inner and outer layers of the Bruch’s membrane, beneath the RPE, or in the subretinal space. On incubation with alpha-V beta-3 antibody and alpha-V beta-5 antibody these sections showed distinct red and green fluorescent signals, localized to the endothelium of choroidal neovascular membrane vessels, under the microscope. This staining was not found in the control eyes with normal retinas. Conclusions: Alpha-V beta-3 and alpha-V beta-5 integrins are specific to choroidal neovascular membranes. Proliferating new vessels in CNV, at the level of the endothelium, possess alpha-V beta-3 and alpha-V beta-5 integrins. Thus, conjugation of anti-angiogenic agents with alpha-V beta-3 and alpha-V beta-5 integrin specific monoclonal antibodies may help selectively target neovascular vessels and prove beneficial in inhibiting angiogenesis in AMD.

Keywords: age-related macular degeneration • retina • choroid: neovascularization