Probucol inhibits in-stent thrombosis and neointimal hyperplasia by promoting re-endothelialization

BACKGROUND: Evidence suggests that delayed re-endothelialization is responsible for in-stent thrombosis. Probucol inhibits neointimal thickening in animals via enhanced re-endothelialization and is the only oral drug that consistently inhibits restenosis after coronary angioplasty in humans. Here, we examined the effects of probucol on re-endothelialization and neointimal formation in a stent model. METHODS AND RESULTS: New Zealand White rabbits were fed a hypercholesterolemic diet with probucol (1%) or without (control) (n=11 each) for 6 weeks. At 2 weeks, endothelial denudation and stenting of the iliac artery was performed. Iliac arteries were harvested at week 6, and stented segments sectioned and analyzed. Compared with control, probucol increased in-stent re-endothelialization (74+/-6% in controls versus 93+/-3% in probucol-treated; P=0.008), and decreased average luminal stenosis (58+/-27 versus 31+/-16%; P=0.01) and stent depth (619+/-310 versus 314+/-158mum; P=0.009). Compared with control, probucol also decreased accumulation of macrophages in the neointima. Furthermore, none of the probucol-treated rabbits had in-stent thrombosis, whereas four of eleven control rabbits showed thrombosis (P=0.04). CONCLUSIONS: Probucol demonstrates anti-restenotic and appears to have anti-thrombotic properties that are likely related to its ability to promote in-stent re-endothelialization.