Abstract 611: Promoted Autologous Tissue Regeneration Using a Newly Developed Tissue-Engineered Small Caliber Vascular Graft without Cell Seeding
Background: In recent years, various types of natural and synthetic scaffolds with autologous cells or differentiated stem cells have been attracted much interest as small caliber vascular graft. However, the manufacturing or pretreatment process is complicated, invasive, and time-consuming. We thought it would be more practical if a synthetic graft allowed efficient in situ regeneration without any seeding. In this study, we developed a novel tissue-engineered biodegradable small caliber vascular graft that can promote in situ tissue regeneration without pretreatment of cell seeding and has sufficient durability to be used for small-diameter artery reconstruction.
Methods: Small caliber vascular grafts (4mm in diameter) were fabricated by compounding a collagen microsponge with biodegradable polymeric woven tube constructed in a plain weave using a polyglycolic acid (PGA) and a poly-L-lactic acid (PLLA) double layer thread (core: PGA, outer: PLLA) . These vascular grafts were implanted into the bilateral carotid arteries of mongrel dogs (body weight, 20–25Kg). No anticoagulation regime was used. At 2, 4, 6, and 12 months after the implantation (n = 4 at each point), the grafts were removed for histological and biochemical evaluations.
Results: All the grafts were patent with no sign of thrombus and aneurismal formation up to 12 months. Its luminal surfaces were similar to native arterial tissue. Immunohistological and biochemical examination showed excellent in situ regeneration with endothelial cell monolayer and smooth muscle cells, and reconstructed vessel wall with elastin and collagen fibers at all of the time points.
Conclusions: Our newly developed tissue-engineered biodegradable small caliber vascular graft had excellent patency throughout the 12 months after the implantation. This study provides that this graft has the potential to promote in situ autologous tissue regeneration without cell seeding and thereby confer better patency of small-diameter vascular prostheses.