Immunohistochemical study of angiogenesis and proliferative activity in epiretinal membranes

Abstract

Formation of epiretinal membranes (ERMs) is a serious complication of retinal diseases, the most important being proliferative diabetic retinopathy (PDR) and proliferative vitreoretinopathy (PVR). In this study, our goal was to (i) calculate the microvessel density (MVD), (ii) evaluate vascular endothelial growth factor (VEGF) expression and (iii) correlate angiogenesis with the proliferative activity as expressed by the expression of Ki67 marker, in both membrane types. We performed immunohistochemistry in 14 PVR and eight PDR membranes, using antibodies against CD34, VEGF, Ki67 and glial fibrillary acidic protein. PDR membranes presented higher average count of microvessels compared with PVR membranes (p = 0.0015). No differences were observed concerning VEGF expression (p = 0.1). The expression of Ki67 was not correlated with microvessel number or VEGF expression. Our study confirms the presence of vascularisation in PDR membranes, as well as the presence of VEGF even in avascular PVR membranes, suggesting that immunoreactivity for VEGF may not be accompanied by angiogenesis.

Antiangiogenic Isoforms of Vascular Endothelial Growth Factor Predominate in Subretinal Fluid of Patients With Rhegmatogenous Retinal Detachment and Proliferative Vitreoretinopathy

“…This hypothesis should, however, be treated with caution given the predominance of proangiogenic VEGF isoforms in a subset of our study population. However, there are several immunohistochemical studies 19,20 confirming the presence of vascularization in a substantial portion of PVR membranes. To illustrate, a vascular component, which consisted mostly of capillary-sized vessels that were clinically unapparent, was demonstrated in 28.6% of all PVR membranes investigated in one study.…”

Angiogenesis in pterygium: study of microvessel density, vascular endothelial growth factor, and thrombospondin-1

“…7 Angiogenesis is defined as the formation of new blood vessels from pre-existing vasculature and underlies a large number of physiological processes, 8 such as growth and differentiation, ovulation, would healing, and abnormal conditions such as neoplasia and eye diseases, which cause severe loss of vision. 9 The process of vascularization involves the activation of cell-derived angiogenic factors as well as the appropriate synthesis of extracellular matrix components necessary for anchorage of migrating endothelium. Among others, vascular endothelial growth factor (VEGF) presents of extremely interest, as its expression is induced by hypoxia.…”

Immunohistochemical Profile and VEGF, TGF-β and PGE2 in Human Pterygium and Normal Conjunctiva: Experimental Study and Review of the Literature

“…In addition, many fibroangiogenic growth factors have been implicated in pterygium pathogenesis, such as tumor necrosis factor-a (TNF-a), basic fibroblast growth factor (bFGF), platelet-derived growth factor (PDGF), and transforming growth factor-B (TGF-~) (8). Angiogenesis is defined as the formation of new blood vessels from pre-existing vasculature and underlies a large number of physiological processes (9), such as growth and differentiation, wound healing, and abnormal conditions, such as neoplasia and eye diseases, which cause severe loss of vision (10). The process of vascularization involves the activation of cell-derived angiogenic factors as well as the appropriate synthesis of extracellular matrix components necessary for anchorage of migrating endothelium.…”