Bilayered Nanoparticles with Sequential Release of VEGF Gene and Paclitaxel for Restenosis inhibition in Atherosclerosis.

Complete re-endothelialization followed by inhibition of smooth muscle cell proliferation is considered an effective therapeutic option to prevent restenosis. We have designed poly(lactide-co-glycolide)-loaded bilayered nanoparticles (NPs) with the ability to sequentially release VEGF-encoding plasmids from the outer layer and paclitaxel (PTX) from the core to promote endothelial regeneration while also prevent restenosis. Comparing with conventional NPs, which release VEGF plasmid and PTX simultaneously, we expect that the bilayered NPs could release the VEGF plasmid more rapidly followed by a delayed release of PTX, resulting in efficient VEGF gene transfection, which ideally could promote re-endothelialization while inhibit excessive smooth muscle cell growth. Indeed, in the present study, we have observed efficient gene transfection using a model plasmid as well as cell growth attenuation in vitro using Chinese Hamster Ovary (CHO) cells. Therapeutic efficacy of the bilayered NPs on restenosis was further evaluated in vivo using a rabbit model of atherosclerosis. The bilayered NPs were administered locally via balloon angioplasty to the injured aortic wall through perfusion. Twenty-eight days after NPs administration, rabbits treated with the bilayered NPs exhibited rapid re-endothelialization and inhibition of restenosis as demonstrated by histological analysis. Increased level of VEGF and decreased level of C-reactive protein (CRP), a biological marker that closely related to atherosclerosis, were also observed from animals treated with the bilayered NPs, implicating ameliorated atherosclerosis. Our results suggest that the VEGF plasmid/ PTX loaded bilayered NPs exert a beneficial impact on atherosclerotic restenosis by sequentially releasing VEGF and PTX in vivo.