Pigment epithelium derived factor:a potent inhibitor of angiogenesis

Pigment epithelium-derived factor (PEDF) , a neurotrophic agent first identified in conditioned medium from cultured human retinal pigment epithelial cells, induces neuronal differentiation. DNA sequence analysis shows PEDF belongs to the serine protease inhibitor(SERPIN) gene family, but PEDF does not seem to exhibit antiprotease activity. PEDF have "gliastatic" effect, along with neuron-survival character. PEDF appeared to inhibit angiogenesis by causing apoptosis of activated endothelial cells. The concentration of PEDF in the cornea and vitreous is sufficient to inhibit angiogenic stimulatory activity. PEDF is taken as one of the most effective antiangiogenic factors. It may prove to be a useful therapeutic for neuronal damage and inhibiting angiogenesis may be particularly effective.