Inhibition of neointimal formation after balloon injury by cilostazol, accompanied by improvement of endothelial dysfunction and induction of hepatocyte growth factor in rat diabetes model

Aims/hypothesis. Cilostazol, a well-known phosphodiesterase type 3 (PDE3) inhibitor for the treatment of peripheral arterial disease, has vasodilator properties and an anti-proliferative action on the growth of vascular smooth muscle cells. In this study, we tested whether cilostazol inhibits neointimal formation and improves endothelial dysfunction after balloon injury in non-diabetic and diabetic rats. Methods. Cilostazol or vehicle was administered to non-diabetic and streptozotocin-induced diabetic rats from 7 days before to 14 days after balloon injury of the carotid artery. We focused on the expression of hepatocyte growth factor to explore how cilostazol improved endothelial dysfunction. Also, we studied the effects of cilostazol on hepatocyte growth factor production in in vitro experiments. Results. At 14 days after injury, the ratio of neointimal to medial area was decreased in rats treated with cilostazol in non-diabetic and diabetic animals. The impaired response to acetylcholine in balloon injured vessels was improved by cilostazol in non-diabetic and diabetic rats (p < 0.05). Vascular hepatocyte growth factor concentration was decreased in injured vessels of non-diabetic rats compared to uninjured vessels. Moreover, hepatocyte growth factor was further decreased in injured vessels of diabetic rats as compared to those of non-diabetic rats (p < 0.05). Of note, administration of cilostazol attenuated the decrease in hepatocyte growth factor concentration in injured vessels of both non-diabetic and diabetic rats (p < 0.01). Increase in vascular hepatocyte growth factor by cilostazol was confirmed by in vitro experiments showing that cilostazol increased hepatocyte growth factor concentration in cultured human vascular smooth muscle cells, accompanied by cAMP accumulation. Conclusion/interpretation. Our study shows that the increase in vascular hepatocyte growth factor by cilostazol could improve abnormal growth of vascular smooth muscle cells and endothelial dysfunction through rapid regeneration of endothelial cells.