Small molecules promote the in vitro expansion and passaging of adult mouse pancreatic islets.

Islet-like organs can provide a new solution for the treatment of diabetes and personalized drug testing. However, because adult pancreatic tissue lacks regenerative capacity, it is still not possible to expand islet clusters from adult mice in vitro or to further passage them. Here, we describe a small molecule-based culture medium that contains specific compounds that can amplify pancreatic clusters from adult mice; these clusters also express markers similar to those of primary pancreatic islets. In addition, the short passage of pancreatic islet clusters can be achieved through their aggregation on microporous plates. Further mechanistic analysis revealed that WS6+GABA in the culture medium contributes to the expansion of pancreatic islets, while AS8351 contributes to the expression of insulin in pancreatic islet clusters. Finally, we developed a simple mouse islet eyeball transplantation device, which increases the simplicity and speed of islet transplantation. We constructed an expandable functional islet-like organ culture system derived from adult mouse pancreatic tissue and expanded the adult tissue source of islet-like organs, which are important steps for the in vitro expansion of islet tissue and the development of culture media. It is crucial for the future treatment of diabetes, especially for regeneration of the pancreas, and the use of personalized drugs that a large number of islets be derived from the same person.