Abstract 14338: Fast Degrading Tissue-Engineered Vascular Graft With High Cellular Infiltration Inhibits Calcification of the Graft

Introduction: Tissue-engineered vascular grafts (TEVGs) are biologically active grafts which are entirely reconstituted by host-derived cells over an inflammation-mediated degradation process. Calcification of the graft is a detrimental condition that can severely impact graft performance. Therefore, preventing graft calcification is of great importance to success of arterial TEVGs. Hypothesis: We assessed the hypothesis that the fast degrading TEVGs with high cellular infiltration into the scaffold could inhibit calcification of the grafts. Methods: We created two versions of aortic TEVGs: 1) Slow Degrading (SD) group and 2) Fast Degrading (FD) group. Both groups had the same inner layer composed of a 50:50 poly (l-lactic-co- ε -caprolactone) copolymer (PLCL) scaffold. However, the outer layer of the SD group was composed of a poly (l-lactic acid) (PLA) nano-fiber whereas the outer layer of the FD group was composed of a combination of PLA and polyglycolic acid (PGA) nano-fiber. The PGA in the outer layer of the FD group will degrade around 2-4 weeks after implantation, which will let more inflammatory cells infiltrate the scaffold than in the SD group. Both TEVGs were implanted in 8-10 week old female mice (n = 10 in each group) as infra-renal aortic interposition conduits. Animals were followed for 8 weeks. Results: In the SD group, acute thrombosis occurred in two mice. Von Kossa staining showed calcification of the scaffold in 6 out of 8 grafts in the SD group, but none in the FD group (Fig. A). The cell number in the outer layer of the FD group was significantly higher than in the SD group (2.65 ± 1.91 x 10 3 /mm 2 vs. 0.87 ± 0.65 x 10 3 /mm 2 , FD group and SD group, respectively, p =0.02); no significant difference was observed in the inner layer (1.80 ± 0.53 x 10 3 /mm 2 vs. 1.75 ± 0.60 x 10 3 /mm 2 , FD group and SD group, respectively, p =0.85) (Fig. A, B). Conclusions: In conclusion the fast degrading TEVG with high cellular infiltration inhibited calcification of the grafts.