Cathepsin S expression is up-regulated following balloon angioplasty in the hypercholesterolemic rabbit

Neointimal development following balloon angioplasty involves many factors including smooth muscle cell (SMC) migration and proliferation and extracellular matrix (ECM) remodeling. Further, in hypercholesterolemic (HC) conditions, there is an influx of macrophage foam cells (FCs) into the restenotic lesion, which also involves degradation of the basement membrane and surrounding ECM. The ECM remodeling that occurs during restenosis has been shown to be mediated by various proteases. Here we have investigated the role of cathepsin S (CatS), a cysteine protease, in this process. We have demonstrated by Taqman quantitative PCR, Western blot, and immunohistochemistry that CatS is up-regulated in restenotic lesions of HC rabbits following balloon injury of the iliofemoral artery. CatS mRNA expression was elevated 28-fold in balloon-injured vessels relative to uninjured contralateral vessels in HC rabbits 8 weeks post-angioplasty (p