A new look at diabetes

A basic assumption about the biology of diabetes - the pancreas is wrong - and that one of the most active areas of diabetes research today could be misguided, Harvard scientists announced.

Scientists have long believed that many of the body's vital organs are home to elusive populations of adult stem cells, flexible cells with the ability to rebuild that organ. In the case of diabetes, researchers have had been hoping to cure the debilitating disease by finding stem cells in the pancreas that could help the body regain its ability to create insulin.

But now Harvard biologist Douglas Melton has discovered that the cells that make insulin - called beta cells - are rarely, if ever, produced by adult stem cells x and that the pancreas may have no stem cells at all, report boston.com

Harvard cell biologist and study leader Douglas Melton, a vocal proponent of research on embryonic stem cells, said the new experiments, done with mice, undermine previous results that had seemed to show the existence of "adult pancreatic stem cells." Those studies, also limited to mice, had offered evidence that certain organs in adult animals harbored stem cells that could transform themselves into insulin-producing "beta cells," which are missing or not working in diabetics. If similar cells exist in human adults, some proposed, perhaps they could be coaxed in laboratory dishes to become beta cells for transplantation into diabetics. But the new study, Melton said, "provides no evidence whatsoever for the existence of an adult pancreatic stem cell." The findings feed into a highly politicized battle over the existence and relative therapeutic potential of various kinds of stem cells -- self-replenishing cells that can morph into other kinds of body cells, informs washingtonpost.com According medicalnewstoday.com Melton emphasized that although the results by his group cannot rule out the existence of beta-cell-producing adult stem cells, “they raise the bar on trying to demonstrate their existence. In these experiments, we find no evidence for the existence of adult pancreatic stem cells,” he said.

The genetic lineage tracing technique devised by Melton's group is a tool that can now be used to trace the origin of cells involved in the maintenance and repair of other types of tissue. Melton and his colleagues are already using the technique to determine the origin of new cells in lung tissue. And it should be possible to apply the technique to understand the origin of cancer cells in tumors or to understand the role of stem cells in such malignancies, Melton said.