Tin ethyl etiopurpurin significantly inhibits vascular smooth muscle cell proliferation in vivo.

Smooth muscle cell proliferation is a major component of restenosis following angioplasty. Hematoporphyrin derivative and other photosensitive compounds inhibit proliferation by causing cellular necrosis upon light activation (photodynamic therapy). Other photosensitive compounds, such as benzoporphyrin derivative, have been suggested as having non-cytotoxic antiproliferative effects without photodynamic therapy, although other studies using benzoporphyrin derivative were negative. Inhibition of smooth muscle cell proliferation was examined in an in vivo rabbit model of vascular injury using a novel synthetic chlorin derivative, tin ethyl etiopurpurin, and benzoporphyrin derivative without photodynamic therapy. Tin ethyl etiopurpurin and benzoporphyrin derivative inhibited smooth muscle cell proliferation by 50-90% of control (p < or = 0.05) without toxic side effects. These results suggest that tin ethyl etiopurpurin and benzoporphyrin derivative without photodynamic therapy may provide a novel and potent antiproliferative therapy that might be useful in the treatment of restenosis.