Survivin (also termed Birc5) belongs to the family of genes known as inhibitors of apoptosis, and it has been implicated in both prevention of cell death and control of mitosis. The survivin pathway is exploited in cancer, but its potential role in vascular injury is unknown. Here, we show that balloon-mediated arterial injury in rabbits resulted in expression of survivin in vascular cells. Serum or PDGF-AB stimulated survivin expression in cultured smooth-muscle cells (SMCs), which suppressed apoptosis and prevented caspase activation. Adenoviral delivery of a phosphorylation-defective survivin mutant reversed the cytoprotective effect of PDGF in SMCs without affecting mitotic progression, suppressed neointimal formation in wire-injured mouse femoral arteries, and induced vascular cell apoptosis in vivo. These data identify survivin as a critical regulator of SMC apoptosis after acute vascular injury. Disrupting the survivin pathway may provide a novel therapy to limit pathological vessel-wall remodeling.

Objective-Survivin (SVV) is an inhibitor of apoptosis protein (IAP) that is upregulated in cancer and has recently been implicated in vascular injury. We sought to investigate the role of SVV in vein graft hyperplasia. Methods and Results-Adenoviral constructs expressing a dominant-negative (AdT34A) and wild-type (AdWT) SVV were used. Proliferation and apoptosis were assayed on endothelial cells (ECs) and smooth muscle cells (SMCs) from human saphenous vein. A rabbit carotid interposition vein graft model (Nϭ31) was used, with adventitial gene transfer of SVV constructs. In vitro, overexpression of SVV was associated with protection from cytokine-induced apoptosis in ECs and SMCs; conversely, AdT34A directly induced apoptosis in these cells. SMC proliferation was increased by AdWT infection, whereas AdT34A reduced proliferation; both effects were serum-dependent. Expression of plateletderived growth factor (PDGF) in SMCs was regulated by functional SVV expression in analogous fashion. In vivo, proliferation and apoptosis (7 days), as well as wall thickness (30 days), were modified by adenoviral-mediated SVV expression. Adventitial angiogenesis was regulated by the SVV-expressing constructs in a fashion parallel to wall thickness changes. Conclusions-SVV