Background: Constrictive remodeling is thought to be more important than neointimal formation in coronary restenosis after balloon angioplasty. The inhibition of Rho-kinase prevents neointimal proliferation, but now this inhibition that affects constrictive remodeling remains unknown. To explore this issue further, we investigated whether a specific Rho-kinase inhibitor, Y-27632, could suppress restenosis after coronary balloon angioplasty in a porcine model.
Methods: Balloon angioplasty with local administration of Y-27632 (Y group) or vehicle (C group) was performed at 2 and 3 weeks after overstretch injury in a porcine coronary artery. Quantitative coronary angiography (QCA) and quantitative coronary ultrasound (QCU) were performed to assess the coronary lesion segment. A morphometrical analysis was performed in a histological study. Proliferative cells and p27(Kip1)-positive cells were evaluated in the arterial wall using immunohistochemistry.
Results: QCA and QCU demonstrated that the minimal lumen diameter and minimal lumen area were greater, and % stenosis was less in the Y group than in the C group. The QCU analysis also revealed a significant inhibition in the increase of the intimal area and a prevention of constrictive remodeling by Y-27632. In the histological study, the intimal, adventitial and collagen areas were significantly smaller in the Y group than in the C group. The Y group also exhibited significantly less proliferative activity and a significantly higher percentage of cells expressing p27(Kip1) in the arterial wall.
Conclusion: Local delivery of Y-27632 suppressed constrictive remodeling as well as neointimal formation after coronary balloon angioplasty in pigs.