Tailoring of cardiovascular stent material surface by immobilizing exosomes for better pro-endothelialization function.

Stent intervention as available method in clinic has been widely applied for cardiovascular disease treatment for decades. However, the restenosis caused by late thrombosis and hyperplasia still limits the stents long-term application, and the essential cause is usually recognized as endothelial functionalization insufficiency of the stent material surface. Here, we address this limitation by developing a pro-endothelial-functionalization surface that immobilized a natural factors-loaded nanoparticle, exosome, onto the poly-dopamine (PDA) coated materials via electrostatic binding. This PDA/Exosome surface not only increased the endothelial cells number on the materials, but also improved their endothelial function, including platelet endothelial cell adhesion molecule-1 (CD31) expression, cell migration and nitric oxide release. The pro-inflammation macrophage (M1 phenotype) attachment and synthetic smooth muscle cell proliferation as the interference factors for the endothelialization were not only inhibited by the PDA/Exosome coating, while the cells were also regulated to anti-inflammation macrophage (M2 phenotype) and contractile smooth muscle cell, which may contribute to endothelialization. Thus, it can be summarized this method has potential application on surface modification of cardiovascular biomaterials.

Effects of degradation products of biomedical magnesium alloys on nitric oxide release from vascular endothelial cells.

Nitric oxide (NO) released by vascular endothelial cells (VECs), as a functional factor and signal pathway molecule, plays an important role in regulating vasodilation, inhibiting thrombosis, proliferation and inflammation. Therefore, numerous researches have reported the relationship between the NO level in VECs and the cardiovascular biomaterials' structure/functions. In recent years, biomedical magnesium (Mg) alloys have been widely studied and rapidly developed in the cardiovascular stent field for their biodegradable absorption property. However, influence of the Mg alloys' degradation products on VEC NO release is still unclear. In this work, Mg-Zn-Y-Nd, an Mg alloy widely applied on the biodegradable stent research, was investigated on the influence of the degradation time, the concentration and reaction time of degradation products on VEC NO release. The data showed that the degradation product concentration and the reaction time of degradation products had positive correlation with NO release, and the degradation time had negative correlation with NO release. All these influencing factors were controlled by the Mg alloy degradation behaviors. It was anticipated that it might make sense for the cardiovascular Mg alloy design aiming at VEC NO release and therapy.