['Constrictive remodeling of the neointima results in the late lumen loss and restenosis after balloon angioplasty. Intense expression of alpha8beta1 integrin in the contractile state of vascular smooth muscle cells (VSMCs) and in myofibroblasts led us to hypothesize that it might be involved in the process of late constrictive remodeling.', 'Balloon injury was used to induce neointima formation in the rat carotid artery. Immunohistochemical analysis and immunoconfocal studies showed that late lumen narrowing was concomitant with the up-regulation of smooth muscle alpha-actin and alpha8 integrin in the neointima. The transforming growth factor-beta (TGF-beta)-induced contractile properties of fibroblasts and VSMCs populated in a three-dimensional collagen matrix was associated with up-regulation of alpha8 integrin. TGF-beta-induced myofibroblastic features in Rat1 fibroblasts were impaired in cells pretreated with a small interference RNA silencing the alpha8 integrin gene.'] Is alpha8beta1 Integrin up-regulated in the neointima concomitant with late luminal loss after balloon injury?