Survivin expression is up-regulated in vascular injury and identifies a distinct cellular phenotype

Abstract

Objectives: The healing response to vascular injury is characterized by neointimal thickening. Proliferation and phenotypic transformation of vascular smooth muscle cells (SMCs) have been implicated in this process. We sought to investigate the role of survivin, a dual regulator of cell proliferation and apoptosis, in lesion formation after diverse forms of vascular injury.

Methods: Rabbits underwent either carotid interposition vein grafting (n = 17) or bilateral femoral balloon injury (BI; n = 29); some in the BI group were placed on a high-cholesterol diet. A subset of BI arteries were treated with local adenoviral gene delivery of a survivin dominant negative-mutant (AdT34A) versus vector or saline controls. Survivin expression in vessels was analyzed by quantitative reverse transcriptase polymerase chain reaction (RT-PCR) and by immunohistochemistry (IHC), which also included markers of SMC differentiation. Specimens of human tissue including failed lower extremity bypass grafts and carotid plaque were also examined.

Results: RT-PCR and IHC demonstrated increased survivin expression in all experimental models, colocalizing at early times with proliferating and alpha-actin-expressing cells but was largely absent in mature, contractile SMCs. Delivery of AdT34A after BI attenuated neointimal hyperplasia.

Conclusion: These studies provide strong evidence supporting a role for survivin in the cellular response to vascular injury.

Clinical relevance: The regulation of cell proliferation, death, and phenotype after vascular interventions remains incompletely understood. We investigated the role of the inhibitor of apoptosis protein survivin in diverse models of vascular injury. The results suggest that survivin is an important modulator of the generalized vascular injury response and may represent a relevant target for therapies targeting intimal hyperplasia.