Isolation and identification of stimulatory and inhibitory cell growth factors in bovine vitreous

Using Bio-Gel P-10 chromatography and an endothelial cell assay system, we have identified and partially characterized stimulatory and inhibitory cell growth factors in adult, newborn and fetal bovine vitreous. The sensitivity of these two factors to boiling and trypsin treatment suggest that they are proteins. The stimulatory factor appears near the void volume (mol. wt cut-off 13000) and increases endothelial and smooth muscle cell, as well as fibroblast proliferation. It appears related to ischemic and/or necrotic retinal tissue. The inhibitory factor, estimated to be of 6200 mol. wt, appears in the retarded volume and inhibits endothelial and smooth muscle cells to a greater degree than fibroblasts. It appears native to the vitreous and may be a product of hyalocytes which, in culture, produce an endothelial cell inhibitory factor.