Abstract 309: In vivo Regeneration of Small-Diameter Arteries Using a Novel Tissue-Engineered Biodegradable Vascular Graft without ex vivo Cell Seeding
Background: In the area of vascular surgery, vascular prostheses made from ePTFE or Dacron are clinically used for the reconstruction of large-diameter arteries. However, these synthetic materials are not suitable in the case of small-diameter arteries (<5mm) because small-diameter vascular prostheses were occluded soon after implantation by the thrombus on the luminal surfaces. Therefore, no clinically applicable small-diameter prostheses have been established to date. We developed a novel tissue-engineered biodegradable small-diameter vascular graft that can promote tissue regeneration without ex vivo cell seeding and that has sufficient durability to be used for small-diameter artery reconstruction. Materials and Methods: The small-diameter vascular graft (4mm in diameter and 30mm long) was fabricated by compounding a collagen-microsponge with biodegradable polymeric woven tube that was constructed in a plain weave with polyglycolic acid (PGA) and poly-L-lactic acid (PLLA) double layer fiber (core: PGA, outer: PLLA). We implanted the vascular grafts into the bilateral carotid arteries of mongrel dogs (body weight, 20–25Kg). No anticoagulation regime was used. We sacrificed the dogs after 2 (n=4) and 4 months (n=4), and histological and biochemical evaluations were performed. Results: All the small-diameter vascular grafts were patent with no sign of thrombus and aneurismal formation both after 2 and 4 months of implantation. Its luminal surfaces were similar to native arterial tissue. Immunohistological examination showed endothelial cell monolayer and smooth muscle cells. Conclusion: These results indicate that a novel tissue-engineered biodegradable vascular graft may promote In vivo tissue regeneration and thereby confer better patency evaluations of small-diameter vascular protheses.