AlphaB-crystallin in Fibrovascular Membrane of Human Proliferative Diabetic Retinopathy

Abstract

Purpose: : Recently, we reported that alphaB-crystallin, a molecular chaperone to vascular endothelial growth factor (VEGF), prevented VEGF protein from degradation, consequently promoting angiogenesis (Kase et al, Blood 2010). In this study, we examined the expression of alphaB-crystallin and its co-localization with VEGF in fibrovascular membranes (FVMs) of human proliferative diabetic retinopathy (PDR).

Methods: : Ten FVMs, surgically excised from patients with PDR, were analyzed in this study. As a control, a normal retina obtained by orbital exenteration in a 50-year-old patient due to squamous cell carcinoma invading the orbit without diabetes mellitus was used. The tissues were fixed with paraformaldehyde, embedded in paraffin, and were subjected to immunohistochemistry for alphaB-crystallin, VEGF, and CD31.

Results: : AlphaB-crystallin expression was found in all the FVMs examined. Immunolocalization of alphaB-crystallin was detected in the cytoplasm of CD31-posivtive endothelial cells in the FVMs, but not in the normal retina. Furthermore, alphaB-crystallin was co-localized with VEGF expression in these FVMs.

Conclusions: : AlphaB-crystallin was expressed and co-localized with VEGF in the FVMs obtained from PDR patients. Our data suggest that alphaB-crystallin plays a role in the formation of FVM in PDR, functioning as a molecular chaperone for VEGF.

Keywords: diabetic retinopathy • immunohistochemistry • retinal neovascularization