Cultivation of retinal pigment epithelial cells from human choroidal neovascular membranes in age related macular degeneration

A method is described for cultivating retinal pigment epithelial cells from choroidal neovascular membrane (CNV) specimens that were surgically removed in patients with age-related macular degeneration (AMD). CNV specimens of 43 patients were available for cultivation. They were incubated in supplemented DMEM/Ham's F12 cell culture medium on microporous semipermeable filter membranes. Thirty-four specimens gave rise to cell cultures, 28 of which could be subcultivated for up to 15 passages. The membrane type as classified by fluorescence angiography was compared with cellular growth in vitro. Immunocytochemistry revealed a uniform expression of cytokeratin 18 and vimentin, while factor 8, glial fibrillary acidic protein and alpha smooth muscle actin were absent in all 21 cultures stained. The expression of RPE markers cellular retinaldehyde binding protein (CRALBP) and RPE65 was detected by RT-PCR in all cultures tested. An epithelial character of the cultures was supported by the presence of apical microvilli as determined by electron microscopical studies. Therefore, the cell cultures from CNV in AMD bear characteristics of retinal pigment epithelial cells. For the first time, this cell culture system holds the potential to study human RPE cells in the context of neovascular AMD in vitro.