PRESENCE OF GROWTH-STIMULATING FIBRIN DEGRADATION PRODUCTS CONTAININGFRAGMENT-E IN HUMAN ATHEROSCLEROTIC PLAQUES

The key event in the formation of stenosing; atherosclerotic lesions i s widely thought to be smooth muscle cell proliferation, but the facto rs primarily responsible for initiating this remain uncertain. Previou sly we have shown that aqueous extracts of proliferative types of huma n atherosclerotic plaque stimulate cell proliferation in the chick cho rioallantoic membrane (CAM). This has been attributed largely to the f ibrin degradation products in the extracts, components removeable by a ffinity chromatography. We now demonstrate that the fibrinogen content of the extract, removeable by clotting out with thrombin, also makes a contribution to the activity by forming fibrin on the surface of the CAM. Affinity chromatography experiments using anti fragment D and E antisera indicate that activity resides in the E-containing fibrin fra gments, consistent with previous work with FDP prepared in vitro.