INHIBITION OF SMOOTH-MUSCLE CELL-PROLIFERATION AND DNA-SYNTHESIS BY VASOPRIN - A BIOLOGIC RESPONSE MODIFIER

The effect of Vasoprin, a biologic response modifier (BRM), on smooth muscle cell DNA synthesis and intimal proliferation was studied. In th is report, we have measured DNA specific activity (SA) and intimal thi ckening following balloon injury (balloon de-endothelialization (BDE)) after administration of Vasoprin. Various dose schedules were employe d to assess Vasoprin's effect post BDE. Forty-eight hours following va scular injury (the peak of SMC DNA synthesis), Vasoprin administered a t various treatment schedules showed between 54% and 72.6% +/- 9% (P < 0.0012) inhibition of DNA SA compared with vehicle controls. Vasoprin also diminished SMC intimal thickening following its administration. Seven days after vascular injury, at which time SMC neointimal prolife ration reaches its peak, Vasoprin treated animals showed marked reduct ion in intimal thickening by 45.5% +/- 6.6% (P < 0.008), compared with the BDE rats receiving an agent vehicle as controls. The results of t his report demonstrate that a biologic response modifier (Vasoprin) ha s a profound effect on SMC proliferation, and that the immune system m ay be a component in the progression of intimal thickening and hence v ascular closure.