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The Scientist 14[23]:20, Nov. 27, 2000 http://www.thescientist.com/yr2000/nov/research_001127.html Pancreas Goal: To replace insulin-producing islet ß cells destroyed in some types of diabetes. Stem cell research involving the pancreas seemed to score two home runs this year. In February, Bernat Soria and colleagues at the Universidad Miguel Hernandez in San Juan, Spain, reported that they had obtained insulin-secreting cells from mouse ESCs by using antibiotic selection under the control of the insulin gene's regulatory regions.13 Soria says he is now trying to replicate his results using human ESCs. (A poster at a recent diabetes meeting, meanwhile, is said to have announced that human ESCs differentiate spontaneously into insulin-positive cells.) A month after the Soria paper came out, a team of researchers led by Ammon B. Peck, a professor of pathology, immunology, and laboratory medicine at the University of Florida College of Medicine in Gainesville, reported a second major advance. They claimed to have reversed diabetes in non-obese diabetic (NOD) mice by transplanting islets generated in vitro from pancreatic ASCs, which had not been previously isolated.14 NOD mice are the best current model for autoimmune diabetes. Nora D. Sarvetnick, a professor of immunology at Scripps Research Institute, is puzzled by Peck's results. "Unless you immunosuppress the mouse" --which wasn't done--"the mouse is just going to reject the ß cells," she contends. Peck responds that cells grown in culture, such as his ASC-derived islets, sometimes exhibit lower antigenicity for unknown reasons. Susan Bonner-Weir, an associate professor of medicine at Harvard Medical School, objects that the amount of insulin in Peck's ASC-derived islet cells was "orders of magnitude" too low. "What they were putting in [the NOD mice] would have been a very minuscule amount," she says, though she concedes that more insulin might have been made if the islet cells differentiated further inside the mice. Bonner-Weir's own work involves expanding human pancreatic duct cells in vitro, then turning them into insulin-producing islet cells.15 She calls the duct cells, which are differentiated, "functional stem cells" because they undergo scores of doublings in culture and help to regrow pancreas after a portion is removed. ************************