Ginkgolide A-gold nanoparticles inhibit vascular smooth muscle proliferation and migration in vitro and reduce neointimal hyperplasia in a mouse model

Background: Neointimal formation is mediated by phenotypic changes in vascular smooth muscle cells (SMC) and is an important mediator of restenosis following arterial reconstruction. We conjugated antioxidant ginkgolide A (GA) to gold nanoparticles (GNP) to determine the effect of GA delivery on neointimal formation. Materials and Methods: GA was conjugated to 80 nm GNP in an overnight incubation. Mouse P53LMAC01 vascular SMC were treated with various doses of GA-GNP, GA alone, GNP alone, and no treatment control. Cell proliferation and migration were analyzed, and superoxide anion levels and the phosphorylation status of ERK1/2 were determined. Mice underwent ligation of the common carotid artery along with local treatment with GNP (control) or GA-GNP. The carotid artery was harvested and subjected to immunohistochemical analysis. Results: GA-GNP treatment significantly inhibited SMC proliferation and migration in vitro in comparison to GNP treatment alone, and the effect persisted for up to 72 h after treatment. Treatment with GA-GNP also reduced superoxide anion levels in vitro. PDGF-BB substantially induced ERK1/2 phosphorylation in GNP control cells; this PDGE-BB induced ERK1/2 phosphorylation was significantly inhibited in GA-GNP-treated cells compared with GNP only. GA-GNP significantly reduced neointimal hyperplasia after injury in mice, and proliferating cell nuclear antigen (PCNA) staining was reduced substantially in the arteries of mice treated with GA-GNP. Conclusions: GA-GNP reduce vascular SMC proliferation and migration in vitro through reduced activation of ERK1/2. Local treatment with GA-GNP in areas of arterial injury reduced neointimal hyperplasia and subsequent stenosis.