Cilostazol inhibits high glucose- and angiotensin II-induced type 1 plasminogen activator inhibitor expression in artery wall and neointimal region after vascular injury

Increased expression of plasminogen activator inhibitor-1 (PAI-1) in vascular tissues is a potential factor linking diabetes to restenosis after percutaneous coronary intervention. Recent studies have shown that cilostazol, a selective type 3 phosphodiesterase inhibitor, prevents neointimal hyperplasia and in-stent thrombosis in patients with diabetes after coronary angioplasty and stent implantation. However, the molecular mechanism of this drug has not been fully elucidated. We examined whether cilostazol inhibits PAI-1 expression in vascular smooth muscle cells (VSMCs) and neointimal hyperplasia. We found that cilostazol effectively inhibits angiotensin II-, high glucose- and TGF-β-stimulated PAI-1 expression in vivo and in vitro. Cilostazol attenuated PAI-1 expression in neointimal regions and inhibited neointimal hyperplasia after balloon injury. Cilostazol inhibited PAI-1 expression by multiple mechanisms including downregulation of TGF-β, JNK and p38 signaling pathways. Cilostazol also inhibited transactivating activity at the PAI-1 promoter by Smad3, leading to a suppression of PAI-1 gene transcription. Taken together with its antiproliferative effect on VSMCs, this may explain how cilostazol exerts its antithrombogenic effects after angioplasty and stent implantation.