Basic Research On Application Of Three-layered Bioinspired Artificial Arteries For Transplantation

【Background】In peacetime,the incidence of ischemic heart disease and peripheral vascular injury caused by tumor invasion is increasing in China.Moreover,due to the increasing of various military operations,the incidence of vascular injury seriously threaten the live of soldiers during the war.To resolve the above clinical questions,an ideal vascular graft is required to be discovered urgently.Currently,there are three sources of available vascular grafts: autologous,allogeneic,and artificial arteries.The source of autologous blood vessels is limited to be got,while allogeneic blood vessels is immunogenicity and cytotoxicity.Interestingly,researchers have payed close attention to the artificial arteries because of wide source of this materials,abundant optional models and high biological safety.However,the shortcomings such as the rupture and obstruction of small-diameter artificial arteries(diameter < 6 mm),have led artificial arteries to failure in limit of their large-scale clinical application.Therefore,artificial arteries should have well mechanical properties to tolerate high blood pressure and prevent vascular rupture;it also need to have excellent biological properties to fuse with native blood vessels and prevent vascular obstruction.Through literature review,we constructed three-layered bioinspired arteries of PCL/PU(polycaprolactone/polyurethane)using electrospinning technology,which simulated the three-layered structure and function of native blood vessels,respectively.Based on this new material,the purpose of this study is to solve the problem of artificial arteries rupture and obstruction.【Purpose】Through the verification of three-layer bioinspired artificial arteries’ material properties,the feasibility of the new vascular grafts for the treatment of wounded in peacetime and wartime was comprehensively evaluated in vitro biocompatibility and in vivo animal model.【Methods】1.To analyze the structure,morphology,mechanical properties and wettability of three-layered PCL / PU artificial arteries compared with animal artery as control.Comprehensive evaluation of the material properties of the constructed artificial arteries.2.Endothelial cell lines(SVARECs)were used for biological evaluation in vitro.The biocompatibility of the constructed artificial arteries in vitro were evaluated by cell morphology observation,adhesion and proliferation assay,erythrocyte aggregation and platelet adhesion assay.3.The prepared artificial arteries were implanted into the abdominal aorta of rats,and the samples were taken at 30,90 and 180 days respectively.The mechanical properties,histological staining,the reconstruction process and therapeutic effect was used for compared these materials in vivo.【Results】1.The three-layer bioinspired artificial arteries were successfully constructed.The inner layer of the artificial arteries was directional PCL fibers,and the direction is consistent with the long axis of the grafts.The middle layer was PCL/PU mixed layer.The outer layer was disordered PCL fibers.In addition,the mechanical tensile strength and elongation at break of the artificial arteries was higher than those of the native blood vessel,and the burst pressure exceeded the maximum physiological blood pressure value which could tolerate the blood pressure in vivo.2.In vitro,biological evaluation using SVARECs cells cultured on the inner surface of artificial arteries.Through cell culture,it was confirmed that the material had no toxic side effects on the cells,and the cell morphology changed on the surface of the material.The cultured cells showed in a long spindle shape,and the long axis was distributed along the spinning direction.Through erythrocyte aggregation and platelet adhesion evaluation,the data showed that there was no effect on blood compatibility and the surface was difficult for platelets to adhere to form thrombus.3.A rat abdominal aortic defect model was established accompanied with artificial arteries were implanted.Through mechanical property assay,it revealed that the constructed artificial arteries could meet the corresponding mechanical property requirements in vivo.By angiography,B-ultrasound and scanning electron microscopy,the artificial arteries could maintain the vascular structure,patency,no bulge,rupture and other situations after implantation.Through histological related assessment,the artificial arteries was fused with native blood vessels after implantation.【Conclusions】In this study,PCL/PU three-layer biomimetic artificial arteries were constructed by electrospinning technology.Through material performance evaluation,it was confirmed that the artificial arteries had excellent mechanical properties,could tolerate blood pressure changes and prevented rupture.Through biological performance evaluation in vitro,it is confirmed that the artificial artery had well biological performance,no cytotoxicity,and did not cause red blood cell aggregation and platelet adhesion.The transplantation effect evaluation of the artificial artery in animal model demonstrated that the artificial artery had well clinical operability,high patency rate,good fusion with tissue and vascular function.This study preliminarily clarify the performance and application effect of the three-layer biomimetic artificial artery,and provide experimental basis for further application of the artificial artery in the treatment of casualties in peacetime and wartime.