Protein Profiling of Smooth Muscle Cell Responses to Intramural Puromycin Administration Upon Balloon Angioplasty In Rabbit Model

Percutaneous transluminal coronary angioplasty (PTCA) is an effective procedure to decrease severity of stenotic coronary atherosclerotic lesions. However, its long-term success is limited by formation of restenosis or neointima by increased proliferation of smooth muscle cells (SMC) and synthesis of extracellular matrix (ECM). Polypeptide growth factors are potent SMC mitogens and involved in SMC proliferation and ECM synthesis. In this line, inhibition of de novo protein synthesis might be beneficial.
We examined the effect of different concentrations of translational inhibitor puromycin on SMC proliferation, apoptosis, necrosis in vitro. Further, we examined the effect of local administration of puromycin in a rabbit balloon injury model of the iliac artery. Injection of puromycin or its vehicle was performed with an infusion-balloon catheter directly into the vessel wall during angioplasty. PTA in the vehicle group resulted in neointima formation 3 weeks after the vascular intervention. In contrast, puromycin treatment resulted in a significant reduction of intima media ratio. We observed decreased elastin and collagen III synthesis in puromycin treated animals. With proteomics we could demonstrate reduced protein expression of lamin, vimentin, alpha-1-antitrypsin, alpha actin allowing puromycin treatment. In in vitro experiments puromycin decreased smooth muscle cells proliferation (i.e., BrdU incorporation) following FCS stimulation.

Our results suggest that local administration of puromycin directly into the vessel wall during angioplasty is a highly effective approach to prevent restenosis due to reduced SMC proliferation and diminished ECM synthesis.