THE SIGNIFICANCE OF VITRONECTIN IN PROLIFERATIVE DIABETIC-RETINOPATHY

Vitronectin, an integrin-binding a-1-glycoprotein with potent cell-adh esion and proliferation-mediating properties, has been shown to be inc orporated in surgically removed membranes from patients with prolifera tive vitreoretinopathy (PVR), proliferative diabetic retinopathy (PDR) and macular pucker. Therefore we developed an ELISA technique to quan tify levels of vitronectin in human vitreous and plasma samples in ord er to be able to evaluate the significance of vitronectin in these dif ferent vitreoretinal diseases. Our results indicate a significant incr ease of vitronectin in all proliferative disorders except idiopathic m acular pucker. Adjustment of all probes to equal total protein content yielded a significant increase only in PDR (type II diabetes). Plasma samples demonstrated a significant increase of vitronectin in patient s with type II diabetes suffering from PDR. Therefore, breakdown of th e blood-retina barrier appears to be the most likely explanation for t he increased levels of vitronectin in the vitreous. Our results indica te that vitronectin may not only be involved in the regulation of epir etinal membrane formation at significantly higher levels in patients w ith type II diabetes, but the increase of vitronectin in diabetic plas ma may also help to explain the pathological alteration of the coagula tion cascade in diabetics.