Differential expression of proteoglycans biglycan and decorin during neointima formation after stent implantation in normal and atherosclerotic rabbit aortas

Proteoglycans decorin and biglycan, which bind to TGF-beta, are thought to participate in regulation of extracellular matrix accumulation in arterial intimal hyperplasia. To investigate the correlation of these proteoglycans with the cellular localization and phenotypic modulation of smooth muscle c ells (SMCs), we analyzed the spatial and chronological distribution of thes e proteoglycans and two cytokines, TGF-beta and IL-1 beta, in the process o f neointima formation after stent implantation in the aortas of rabbits fed a high-cholesterol diet (atherosclerotic group) or a regular diet (control group). We implanted metallic stents in the rabbit aortas and harvested th e aortas 4-56 days later for immunohistochemical and mRNA in situ hybridiza tion analyses. In the control group, TGF-beta and biglycan expression was i n correspondence with the chronology and localization of embryonic SMCs. In the atherosclerotic group, TGF-beta and biglycan expression was sustained throughout the experimental period, which was in accord with the prolonged expression of embryonic SMCs. Decorin, which did not occur in neointima in the control group, appeared in the atherosclerotic aortas in the confined a rea of vascular SMCs surrounding the macrophages around the stent wire. The se results indicate that biglycan and decorin kinetics during neointima for mation after arterial injury are distinct, despite their similar constructi on; biglycan synthesis correlates with embryonic SMCs. (C) 2000 Elsevier Sc ience Ireland Ltd. All rights reserved.