蚕丝基小口径人工血管研究进展OACSTPCD

Cardiovascular diseases(CVDs)are a group of diseases with high prevalence,disability and mortality rates,and are the number one killer of human health,with coronary and peripheral occlusive vascular diseases posing a great threat.To reduce the threat of CVDs to human life,small-caliber artificial blood vessel transplantation is a relatively common treatment.The materials widely used for the preparation of artificial blood vessels include polyester,expanded polytetrafluoroethylene,polyurethane and silk,etc.The former three are widely used in large vessel replacement surgery,but their use in small vessels is prone to thrombus formation,which clogs the artificial blood vessels and ultimately leads to the death of the organism.Silk has good biocompatibility,mechanical properties,degradability and promotion of cell adhesion,which has become a research hotspot for the preparation of small-caliber artificial blood vessels in recent years. To comprehensively understand the application status and performance advantages of silk small-caliber artificial blood vessels and accelerate the research and transformation of small-caliber blood vessels,this paper analyzed the advantages and problems of using silk as raw material to prepare small-caliber blood vessels from the aspects of preparation method,biocompatibility,anti-thrombotic ability and promoting vascular endothelialization,and put forward the possible development direction in the future.The results of most of the studies show that small-caliber artificial blood vessels prepared with silk as raw material exhibit good repair and long-term patency in animals.Silk can be prepared by gel spinning,weaving,knitting,electrostatic spinning,3D printing,decellularization,freeze drying,etc.These methods have both advantages and defects.For instance,freeze drying is easy to mold but the mechanical properties of the artificial blood vessels are weak,the method of gel spinning can produce a uniform and loose network structure but is poor in mechanical properties,the artificial blood vessels prepared by knitting have uniform texture and flat surface but are easy to unravel at the anastomosis.On the whole,the artificial blood vessels produced by electrostatic spinning have high porosity to meet the requirements of cell growth,and this method is widely used.Although these methods have defects,they provide researchers with much space for improvement.Silk-based small-caliber blood vessels show effects such as promotion of cell adhesion and proliferation when co-cultured with smooth muscle cells,endothelial cells,fibroblasts,etc.When co-cultured with vascular scaffolds,the cells are able to colonize and grow on the scaffolds smoothly,and these properties indicate that biomedical materials prepared with silk as the raw material have excellent cytocompatibility,but there is an over-proliferation phenomenon when the cells are cultured with smooth muscle,which suggests that over-proliferation of cells should be avoided when silk is used as the biomaterial.The formation of thrombus after vascular transplantation is very likely to lead to death,the excellent mechanical properties and biocompatibility of silk are important factors to avoid the formation of thrombus,but the excessive proliferation of smooth muscle caused by silk-based artificial blood vessels may also lead to thrombus.In the future,artificial blood vessels can be prepared by combining with anticoagulant factors to prevent the formation of thrombus.After silk-based vascular grafting,vascular endothelial cells are able to migrate and colonize into the lumen of the graft smoothly,and the surface of the lumen is able to produce fused endothelium;although this process is relatively slow,it is sufficient to prove that silk-based artificial blood vessels are able to promote the endothelialization process after grafting. Although the advantages of silk-based small-caliber blood vessels are significant,whether the reagent residues in the preparation process have side effects needs to be further verified,and a large number of experimental improvements are needed to accelerate the clinical application,and the amount and degree of endotheliosis are strictly controlled in silk-based vascular grafts.In addition,more in-depth research on their controllable degradation needs be carried out.In conclusion,silk-based small-caliber blood vessels have unique advantages and certain defects,which bring opportunities and challenges for their clinical application,and it is necessary to increase the research investment on silk-based small-caliber blood vessels in the future to promote the development of silk in the field of biomedical materials.