[Development of gastrointestinal regenerative medicine]

Transplantation of the small intestine is rarely performed clinically for the treatment of short bowel syndrome because it is difficult to overcome the powerful rejection response. In contrast, regenerative medicine to restore self-organization is expected to overcome this problem. Here we demonstrate that mouse induced pluripotent stem (iPS) cells have the ability to organize a gut-like organ with motor function in vitro in a hanging drop culture system. This "induced gut (iGut)" exhibited spontaneous contraction and highly coordinated peristalsis accompanied by the transport of contents. The iGut was composed of all the enteric components of the three germ layers: epithelial cells (endoderm); smooth muscle cells (mesoderm); interstitial cells of Cajal (mesoderm); and enteric neurons (ectoderm). This study not only contributes to the understanding of the mechanisms of incurable gut disease through disease-specific iPS cells but also facilitates the clinical application of patient-specific iPS cells for novel therapeutic strategies such as patient-specific organ regenerative medicine in the future.