Electrospun Membranes Loading With MicroRNAs For Enhancing Small-diameter Vascular Regeneration

After the vascular graft is implanted,it is often accompanied by adverse symptoms such as thrombosis,intimal hyperplasia and inflammation.The regulation of vascular endothelial cells(VECs),vascular smooth muscle cells(VSMCs)and macrophages by microRNAs(miRNAs)could possibly cope with the above problems.Trimethylated chitosan-g-poly(ethylene glycol)-REDV(TPR)and trimethylated chitosan-g-poly(ethylene glycol)-VAPG(TPV)were used to complex miRNA-126 and miRNA-145,respectively,to achieve the target regulation of both VECs and VSMCs.TPR/miRNA-126 and TPV/miRNA-145 were loaded to the inner layer of poly(ethylene glycol)-b-poly(L-lactide-co-caprolactone)(PELCL)and the outer layer of poly(L-lactide-co-glycolide)(PLGA)electrospun membranes by emulsion electrospinning,respectively,and bilayered small-diameter vascular graft was prepared.The results showed that the introduction of PEG can accelerate release rate of miR-126 from the inner PELCL electrospun membrane,reaching 61.3±1.2% of the cumulative release in the initial 10 days.The thick-diameter fibers can fulfill prolonged release of miRNA-145 from the outer PLGA electrospun membrane for about 56 days.The dual-loading with miRNA-126 and miRNA-145 in bilayered electrospun membrane was tested in vivo for 8 weeks and suggested to have a positive effect on vascular regeneration.In addition,miRNA-21 was coated with trimethylated chitosan(TMC)and then hyaluronic acid(HA)to prepare nanoparticles.The results showed that the miRNA-loaded TMC/miRNA//HA nanoparticles can be successfully prepared by layer-by-layer coated and the outer layer of HA significantly reduce its cytotoxicity.The nanoparticles can be efficiently taken up by macrophages and can be successfully loaded into electrospun fibers.It was expected to regulate the phenotype of macrophages and reduce inflammatory damage when applied in small-diameter vascular grafts.In summary,this study successfully prepared a bilayered electrospun membrane dual-loading with miRNA-126 and miRNA-145,which can effectively promote vascular regeneration.In this study,layer-by-layer-coated miRNA-21 nanoparticles were prepared,which can be effectively taken by macrophage,providing conditions for inhibiting the inflammatory response after vascular transplantation.