[Pancreatic development and stem cell-based regenerative medicine]

After the gut endoderm is formed, subsequent permissive induction signals from the notochord allows the pancreas to emerge and growout from a specific site of the embryonic gut epithelium. The first pancreas-specific gene, pdx1, is expressed around this stage. Interaction between pancreatic epithelium and the surrounding mesenchyme allows the pancreas bud to further grow and differentiate to form ductal, exocrine or endocrine lineages. Several lines of evidence from gene knockout mice and cell lineage studies suggest that a common pancreas stem cell first gives rise to exocrine and endocrine progenitor cells. The endocrine progenitor then give rise to four different endocrine cells: alpha, beta, delta, and PP cells, although it is not known how and when these cells arise. We have focused our studies on the understanding of endodermal induction and organogenesis of the pancreas. We specifically aimed at the isolation of pancreatic stem cells and the development of functional pancreatic endocrine beta cells in culture. For this aim, we used ES cells as a model system. Here, I review the literature on the development and regeneration of the pancreas. Some recent results on growing pancreatic cells from ES (embryonic stem) cells.