Metallic
stents cause vascular wall damage with subsequent smooth muscle cell (SMC) proliferation, neointimal
hyperplasia, and treatment failure. To combat in-
stent restenosis,
drug-eluting stents (DES) delivering
mTOR inhibitors such as
sirolimus or
everolimus have become standard for coronary stenting. However, the relatively non-specific action of
mTOR inhibitors prevents efficient endothelium recovery and mandates dual antiplatelet
therapy to prevent
thrombosis. Unfortunately, long-term dual antiplatelet
therapy leads to increased risk of
bleeding/
stroke and, paradoxically,
myocardial infarction. Here, we took advantage of the fact that
nitric oxide (NO) increases
Fas receptors on the SMC surface. Fas forms a death-inducing complex upon binding to
Fas ligand (FasL), while endothelial cells (ECs) are relatively resistant to this pathway. Selected doses of FasL and NO donor synergistically increased SMC apoptosis and inhibited SMC growth more potently than did
everolimus or
sirolimus, while having no significant effect on EC viability and proliferation. This differential effect was corroborated in ex vivo pig coronaries, where the neointimal formation was inhibited by the
drug combination, but endothelial viability was retained. We also deployed FasL-NO donor-releasing
ethylene-vinyl acetate copolymer (EVAc)-coated
stents into pig coronary arteries, and cultured them in perfusion
bioreactors for one week. FasL and NO donor, released from the
stent coating, killed SMCs close to the
stent struts, even in the presence of flow rates mimicking those of native arteries. Thus, the FasL-NO donor-combination has a potential to prevent intimal
hyperplasia and in-
stent restenosis, without harming endothelial restoration, and hence may be a superior drug delivery strategy for DES.