A retinal pigment epithelial cell-derived growth factor(s).

Proliferation of retinal pigment epithelial (RPE) cells, fibroblasts, and glial cells has been implicated in the pathogenesis of proliferative vitreoretinopathy. In this study, we demonstrate that RPE cells in culture produce a factor(s) that stimulates the growth of each of these cell types. After 48 hours of incubation with RPE-conditioned media, cell number is increased over that of controls by 110% for RPE cells, 105% for astrocytes, and 360% for corneal fibroblasts. Thymidine incorporation demonstrates that this increase is due to a stimulation of DNA synthesis. Preliminary characterization of the RPE growth-promoting activity demonstrates that it is heat stable, stable to extremes of pH, nondialyzable, and partially trypsin sensitive. These data suggest that RPE cells in culture produce a growth factor(s) targeted primarily at fibroblasts, but that can also stimulate their own growth and that of astrocytes.