Benzoporphyrin derivative monacid ring A (Verteporfin) alone has no inhibitory effect on intimal hyperplasia: In vitro and in vivo results

Benzoporphyrin derivative monoacid ring A (Verteporfin, BPD-MA), a photosen sitizing drug, has been suggested as having inhibitory effects on smooth mu scle cell (SMC) proliferation in rabbit aortic intimal injuries. The effect of BPD-MA on vascular SMCs in the absence of light stimulation in vitro an d in vivo was studied using models of intimal hyperplasia. Human SMCs were incubated with BPD-MA for 4 h in darkness. A small (20%) but significant de crease in viability (n = 42, p <.05) was noted for BPD-MA concentrations ab ove 15 mu g/mL. This was an all-or-none phenomenon with no further decrease in viability at higher concentrations. Treatment with BPD-MA was also carr ied out in vivo using a balloon injury model of intimal hyperplasia in rabb it aortas. Thirty-three rabbits were randomized into five groups and given intravenous BPD-MA (2 mg/kg) according to the following schedule: Group 1 ( n = 8), BPD-MA 25 min prior to injury; Group 2 (n = 8), BPD-MA 25 min prior to injury plus a second dose 4 weeks later; Group 3 (n = 4), BPD-MA immedi ately postinjury; Group 4 (n = 7), BPD-MA immediately postinjury plus a sec ond dose 4 weeks later; or Group 5 (n = 6), no drug (control group). No sta tistically significant difference was seen in the amount of intimal hyperpl asia that developed in the five groups.