FIG. 6.

Gross images of explanted grafts. (A–C) PEVA grafts. (A) Cell-seeded PEVA graft that was explanted from the omentum after 3 weeks. A red rubber catheter had been put in the lumen to try to prevent it from scarring down. Note the adherent omentum and supportive tissue. (B) Cell-seeded PEVA graft after explantation from the omentum at 4 weeks. This graft did not incorporate well and stripped from the surrounding tissue quite easily, leaving behind this somewhat bare graft seen here. (C) Cell-seeded PEVA graft from animal 226, which had been implanted in the omentum for 35 days before anastomosis in continuity with the small bowel. The graft remained in continuity for 5 days before euthanasia and then was explanted. The graft had significant stricture and inflammatory reaction. (D–F) PGS grafts performed better overall compared to PEVA grafts; however, the results were heterogeneous with some scaffolds having some degree of tissue integration and others that had almost none. (D) A seeded PGS graft shows improved integration over PEVA scaffolds after 3 weeks of implantation in surgical models 2 and 3. (E) Seeded PGS graft at 4 weeks with poor tissue integration. The scaffold has scarred into a tight cylinder with no lumen and was completely surrounded by native bowel lumen. (F) Unseeded PGS graft after implantation in surgical model 3 for 6 weeks demonstrated significant inflammation. It also had fibrosed down to a very narrow lumen. Clearly, while these particular scaffolds were good starting points for continuing our tissue-engineered small intestine work in large animals, the scaffolds will need further optimization before it will be successful in large animals.