Vinores S A, Campochiaro P A, McGehee R, Orman W, Hackett S F, Hjelmeland L M
Department of Ophthalmology, University of Virginia, School of Medicine, Charlottesville 22908.
Invest Ophthalmol Vis Sci. 1990 Dec;31(12):2529-45.
Retinal pigment epithelial (RPE) cells, retinal glial, and fibroblasts, three cell types believed to play a role in the pathogenesis of epiretinal membrane formation, were maintained in vitreous culture to determine the influence of vitreous on their ultrastructure and expression of cytokeratin, glial fibrillary acidic protein (GFAP), vimentin, and glutamine synthetase (GS). Using a highly sensitive, preembedding technique for the immunolocalization of these antigens at the ultrastructural level, most RPE cells were found to lose cytokeratin and vimentin within 1 day after seeding on irradiated vitreous. The percentage of keratin-positive cells then increased with time in culture. If the vitreous was placed on RPE cells cultured in monolayer instead of placing the cells on the vitreous, keratin and vimentin were expressed these intermediate filament proteins diminished with time. Glutamine synthetase was found in RPE cells grown in monolayer with or without a vitreous overlay, but not in RPE cells grown on the surface of vitreous. Retinal glial grown on vitreous showed a time-dependent decrease in the number of cells expressing GFAP and a corresponding increase in cells expressing vimentin or GS. Some fibroblasts in vitreous culture expressed vimentin but not the other antigens evaluated. A substantial number of cells in each culture did not stain positively for cytokeratin, GFAP, vimentin, or GS. All three cell types showed phenotypic diversity at the ultrastructural level with each cell type being capable of assuming the same morphologic appearance under certain conditions. These results demonstrate the phenotypic plasticity of RPE cells, retinal glia, and fibroblasts when grown in contact with vitreous and provide further evidence that neither ultrastructure, intermediate filament protein expression, nor the presence of GS is sufficient to determine the cell type of origin of cells in epiretinal membranes.
视网膜色素上皮（RPE）细胞、视网膜神经胶质细胞和成纤维细胞，被认为是在视网膜前膜形成的发病机制中起作用的三种细胞类型，在玻璃体培养中维持生长，以确定玻璃体对其超微结构以及细胞角蛋白、神经胶质纤维酸性蛋白（GFAP）、波形蛋白和谷氨酰胺合成酶（GS）表达的影响。使用一种高度敏感的、在超微结构水平上对这些抗原进行免疫定位的包埋前技术，发现大多数RPE细胞在接种到辐照过的玻璃体上1天内就失去了细胞角蛋白和波形蛋白。然后，角蛋白阳性细胞的百分比随培养时间增加。如果将玻璃体置于单层培养的RPE细胞上，而不是将细胞置于玻璃体上，这些中间丝蛋白的表达会随时间减少。在有或没有玻璃体覆盖的单层培养的RPE细胞中发现了谷氨酰胺合成酶，但在玻璃体表面生长的RPE细胞中未发现。在玻璃体上生长的视网膜神经胶质细胞显示，表达GFAP的细胞数量呈时间依赖性减少，而表达波形蛋白或GS的细胞数量相应增加。玻璃体培养中的一些成纤维细胞表达波形蛋白，但不表达所评估的其他抗原。每种培养物中的大量细胞对细胞角蛋白、GFAP、波形蛋白或GS均未呈阳性染色。所有三种细胞类型在超微结构水平上均表现出表型多样性，每种细胞类型在某些条件下都能够呈现相同的形态外观。这些结果证明了RPE细胞、视网膜神经胶质细胞和成纤维细胞在与玻璃体接触生长时的表型可塑性，并进一步证明，无论是超微结构、中间丝蛋白表达，还是GS的存在，都不足以确定视网膜前膜中细胞的起源细胞类型。
