Sarpogrelate inhibits serotonin-induced proliferation of porcine coronary artery smooth muscle cells: implications for long-term graft patency

Background. Serotonin can induce proliferation of vascular smooth muscle cells. We assessed the ability of a specific serotonin receptor antagonist, sarpogrelate, to inhibit proliferation of cultured porcine coronary artery smooth muscle cells. Methods. Cell proliferation and mitotic activity were measured using 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyltetrazolium bromide. To determine the effect of sarpogrelate on DNA (deoxyribonucleic acid), RNA (ribonucleic acid), and protein synthesis, radioactive incorporation of 3H-thymidine, 3H-uridine, and 3H-phenylalanine, respectively, was used. Synthesis of DNA was also assessed by flow cytometry with propidium iodide as a fluorochrome. Results. Serotonin, platelet-derived growth factor, endothelin, and angiotensin II all induced proliferation of porcine coronary artery smooth muscle cells. Sarpogrelate specifically inhibited the serotonin-induced cytokine trigger but did not influence platelet-derived growth factor–, endothelin–, or angiotensin II–induced cell proliferation. Sarpogrelate inhibited the serotonin-induced increase in intracellular free ionized calcium concentration, prevented mitogen-activated protein kinase activation, and down-regulated expression of the protooncogenes c-fos and c-jun. Sarpogrelate acted at the G1 phase of the cell cycle. Conclusions. These data suggest that sarpogrelate could be used as a therapeutic agent to inhibit serotonin-induced neointimal hyperplasia and improve patency of coronary artery bypass grafts.