Vitreous stimulates proliferation of fibroblasts and retinal pigment epithelial cells

In proliferative vitreoretinopathy, retinal pigment epithelial cells and glial cells migrate into the vitreous, proliferate, and assume characteristics of myofibroblasts. The addition of vitreous to the culture media stimulates the proliferation of porcine retinal pigment epithelial cells, bovine and lapine dermal fibroblasts but not the proliferation of bovine aortic endothelial cells and smooth muscle cells. The mitogenic activity is not species-specific, since vitreous from various species stimulates the proliferation of these cells. The mitogenic activity is destroyed by heating at 100 degrees C for 10 min or by trypsin treatment. Since the vitreous, under our assay conditions, was not mitogenic for endothelial cells or smooth muscle cells, the mitogenic activity is probably not derived from leakage into the vitreous of circulating fibroblast, epidermal or platelet-derived growth factor.