Search

We have established a method for in situ tissue engineering of the stomach in a canine model using an acellular collagen scaffold graft. The current study was conducted to evaluate the functional aspects of the tissue-engineered stomach wall. The anterior wall of the stomach in beagle dogs was replaced with a collagen sponge scaffold measuring 4 x 4 cm. At 16 weeks after implantation, the animals were sacrificed and the stomach specimens were evaluated immunohistochemically and physiologically. Regeneration of the proton pump and thin muscle layer, which are essential for mechanical and chemical digestion by the stomach, was observed in the tissue-engineered gastric tissue. However, acetylcholine-induced contraction was not observed in the tissue-engineered stomach wall. Although there is still room for improvement, the tissue-engineered stomach wall had a highly organized structure, and it is anticipated that this approach could eventually become an alternative for stomach reconstruction after gastrectomy.

Background: We have succeeded in regenerating the small intestine by the use of tissue engineering techniques. However, the regenerated intestine proved to lack the muscle layer, which is essential for functional peristalsis. To induce regeneration of the muscle layer, we focused on autologous mesenchymal stem cells (MSC) as a source of muscle tissue. The aim of this study was to investigate the effect of MSC seeding onto the collagen scaffold on induction of the muscle layer., Materials and Methods: We used six female beagle dogs. The small intestine was resected over a length of 5 cm and reconstructed by a collagen sponge graft in the same way as in our previous study. Autologous MSC derived from bone marrow (10(7) cells) were seeded onto the collagen sponge just before implantation. Animals were sacrificed at 2, 4, and 16 weeks after surgery, and specimens were examined histologically., Results: All six dogs survived until the scheduled time of sacrifice. At 4 weeks, regeneration of the intestine was observed at the reconstructed site. Cells positive for alpha-smooth muscle actin appeared on the scaffold in the MSC-seeded group. However, they disappeared by 16 weeks and only a thin muscle layer regenerated beneath the mucosal layer, although the regenerated mucosal layer covered the luminal surface of the regenerated intestine., Conclusions: MSC seeding induced a transient distribution of cells positive for alpha-smooth muscle actin on the scaffold, but did not induce regeneration of the muscle layer. Further investigation is necessary to achieve this aim., ((c)2001 Elsevier Science.)