[Comparative immunohistochemical studies of epiretinal membranes in proliferative vitreoretinal diseases]

Abstract

Epiretinal membranes are a fibrocellular tissue whose cellular components are macrophages, glial cells, retinal pigment epithelial cells and fibroblasts. In our immunohistochemical study on epiretinal membranes in proliferative vitreoretinopathy (PVR), proliferative diabetic retinopathy, macular pucker, uveitis and after intraocular silicone oil tamponade we analyzed the cellular growth patterns of these histogenetically different cell types on serial sections of paraffin-embedded and frozen material. In addition, the topographic distribution of fibronectin was analyzed and the localization of the epidermal growth factor receptor, which is the coreceptor for the transforming growth factor alpha, was examined by staining procedures. We used antibodies against macrophages (Ki-M7), cytokeratin, vimentin, desmin, glial fibrillary acidic protein and against the proliferation antigen Ki-67. The different cell systems often showed cell-type-specific growth patterns causing an "organoid" structure of the epiretinal membranes. Macrophages predominated in membranes of eyes affected by uveitis and after intraocular silicone oil tamponade. The coexistence of macrophages and other cell types within the same area might be explained by intercellular regulatory mechanisms. Fibronectin, which has functions that are important for cell adhesion, migration, proliferation and differentiation, was topographically localized mainly in areas of denser cell populations and within the walls of newly formed capillaries in diabetic membranes. There was no correlation with specific cell types, however. Among the cellular receptors necessary for signal transduction of mitogenic substances, we localized the coreceptor for the epidermal growth factor and the transforming growth factor alpha among actively proliferating macrophages in a PVR membrane.(ABSTRACT TRUNCATED AT 250 WORDS)