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 this report, we have measured DNA specific activity (SA) and intimal thickening following balloon injury (balloon de-endothelialization (BDE)) after administration of Vasoprin. Various dose schedules were employed to assess Vasoprin's effect post BDE. Forty-eight hours following vascular injury (the peak of SMC DNA synthesis), Vasoprin administered at 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 proliferation reaches its peak, Vasoprin treated animals showed marked reduction 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 this report demonstrate that a biologic response modifier (Vasoprin) has a profound effect on SMC proliferation, and that the immune system may be a component in the progression of intimal thickening and hence vascular closure.