Accelerated endothelialization with a polymer-free sirolimus-eluting antibody-coated stent

Drug-eluting stents have shown an impressive reduction of in-stent restenosis for many years. However, stent thrombosis due to incomplete/late endothelialization has raised major safety concerns. To overcome these problems, we developed for the first time a polymer-free sirolimus-eluting antibody-coated stent (PFSEACS) by combining polymer free and endothelial progenitor cell-capture pro-healing approaches. In the first phase, the stents were prepared by loading sirolimus on the porous outer stent surface and directly fixing the anti-CD34 antibodies without any medium carriers on the blood contacting surface. The dose and elution of sirolimus, the amount and stability of anti-CD34 antibody immobilization, and the rate of CD34+ cell capture were evaluated. In the second phase, the stents were validated in an animal model of coronary arteries in pigs. The stent was observed to start collecting endothelial progenitor cells ~2 h after stent implantation and exhibited greatly enhanced endothelialization while maintaining an excellent anti-restenosis activity comparable to the polymer-free sirolimus-eluting stents. Overall, both in vitro and in vivo evaluations indicated that novel PFSEACSs exhibited facilitated endothelialization with excellent anti-restenosis activity and thus should merit further clinical studies.