A third-generation, long-acting, dihydropyridine calcium antagonist, azelnidipine, attenuates stent-associated neointimal formation in non-human primates

BACKGROUND: Calcium antagonists have been shown to reduce atherogenesis and improve clinical outcomes in atherosclerotic vascular disease. No study has so far, however, addressed the effects of calcium antagonists on stent-associated neointimal formation. We therefore investigated whether a third-generation calcium antagonist, azelnidipine, attenuates in-stent neointimal formation in non-human primates. METHOD: Male cynomolgus monkeys were fed a high cholesterol diet for 4 weeks, and were randomly assigned to three groups: a vehicle group and two other groups treated with azelnidipine at 3 and 10 mg/kg per day for an additional 24 weeks (n = 12 each). Multi-link stents were then implanted in the iliac artery. RESULTS: Azelnidipine at the high dose reduced neointimal thickness (0.25 ± 0.02 versus 0.19 ± 0.02 mm; P < 0.05). Azelnidipine also reduced local oxidative stress and monocyte chemoattractant protein 1 (MCP-1) expression. No difference was found between the three groups in the degrees of injury score, inflammation score, plaque neovascularization, or plasma lipid levels. Azelnidipine also reduced MCP-1-induced proliferation/migration of vascular smooth muscle cells in vitro. CONCLUSIONS: This study demonstrated for the first time that azelnidipine attenuates in-stent neointimal formation associated with the reduced expression of MCP-1 and smooth muscle proliferation/migration in the neointima. These data in non-human primates suggest potential clinical benefits of azelnidipine as a 'vasculoprotective calcium antagonist' in patients undergoing vascular interventions.