Inhibitor of vascular endothelial cell growth in the lens.

Because diabetic eyes with proliferative retinopathy show an increased incidence of iris neovascularization after removal of the lens, we studied the effect of extracts of human and bovine lenses on one of the key events in the neovascular process, endothelial cell proliferation. Both human and bovine lens extracts demonstrated a dose-dependent inhibition of bovine aorta endothelial cell proliferation that was greatest in extracts with molecular weight of less than 100,000. This inhibition was reversible and the extracts did not significantly inhibit smooth muscle cell proliferation. Considerable endothelial cell inhibitory activity was present in bovine lens capsule extracts. These data suggested that the lens may play an active role in the prevention of iris neovascularization.