Engineering small-caliber vascular grafts from collagen filamentsand nanofibers with comparable mechanical properties to nativevessels

摘要

At the present time, there is no successful synthetic, off-the-shelf small-caliber vascular graft (<6 mm)for the repair or bypass of the coronary or carotid arteries. This stimulates on-going investigations tofabricate an artificial vascular graft that has both sufficient mechanical properties as well as superiorbiological performance. Collagen has long been considered as a viable material to encourage cellrecruitment, tissue regeneration, and revascularization, but its use has been limited by its inferiormechanical properties. In this study, novel electrochemically aligned collagen filaments were used toengineer a bilayer small-caliber vascular graft, by circular knitting the collagen filaments andelectrospinning collagen nanofibers. The collagen prototype grafts showed significantly greaterbursting strength under dry and hydrated conditions to that of autografts such as the human internalmammary artery and the saphenous vein (SV). The suture retention strength was sufficient under drycondition, but that under hydrated condition needs to be further improved. The radial dynamiccompliance of the collagen grafts was similar to that of the human SV. During in vitro cell cultureassays with human umbilical vein endothelial cells, the prototype collagen grafts also encouraged celladhesion and promoted cell proliferation compared to the synthetic poly(lactic acid) grafts. Inconclusion, this study demonstrated the feasibility of the use of novel collagen filaments for fabricatingsmall caliber tissue-engineered vascular grafts that provide both sufficient mechanical properties andsuperior biological performance.