FeMOFs/CO loading reduces NETosis and macrophage inflammatory response in PLA based cardiovascular stent materials

Modification of polylactic acid (PLA) is a promising strategy for the next generation of bioresorbable vascular stent biomaterials. With this focus, FeMOFs nanoparticles was incorporated in PLA, and then post loading of carbon monoxide (CO) was performed by pressurization. It showed FeMOFs incorporation increased hydrophilicity of the surface and CO loading, and CO release was sustained at least for 3 days. It is well acknowledged NETosis and macrophage mediated inflammation are the principal effectors of atherosclerosis and cardiovascular disease, and it further increases the risk of late stent thrombosis and restenosis. In this study, the effects of CO release of PLA/FeMOFs/CO on NETosis and macrophage behavior were thoroughly explored. In vitro evaluation results showed that PLA/FeMOFs/CO significantly inhibited neutrophil extracellular traps (NETs) release and neutrophil elastase expression by reducing intracellular reactive oxygen species in a simulated inflammatory environment. It reduced Lipopolysaccharide-induced macrophage inflammation with decreased tumor necrosis factor-α expression and increased IL-10 expression. Meanwhile it enhanced endothelial cell activity and growth in inflammatory environment, and inhibited platelet adhesion and activation. In vivo implantation results confirmed that PLA/FeMOFs/CO reduced the macrophages and neutrophils mediated inflammatory response, thus reduced the neointimal hyperplasia. Overall, PLA/FeMOFs/CO effectively prevented the inflammation and restenosis associated with PLA implantation. Our study provides a new strategy to improve the immunocompatibility of PLA implant materials.