Scientists find pancreatic stem cells in mice
By Julie Steenhuysen
CHICAGO (Reuters) - After most scientists had given up the search, a Belgian team said on Thursday they found elusive pancreatic stem cells in adult mice, a finding that could lead to treatments for people with type-1 diabetes.
Scientists have long hunted for adult cells with the capacity to make insulin-producing cells known as beta cells, which help regulate the body's blood sugar levels.
If coaxed into reproducing, adult stem cells or progenitor cells could offer a way to replace beta cells lost or destroyed in people with diabetes.
"For many years people believed that progenitor cells existed in the adult pancreas but were not able to trace or isolate them," Harry Heimberg, a diabetes researcher at Vrije Universiteit Brussels and the Beta Cell Biology Consortium, said in an e-mail.
More recent studies found that under normal circumstances, adult progenitor cells had little to do with the process of making beta cells, he said.
"Most people gave up looking because they were so few and so hard to activate," Heimberg, whose study appears in the journal Cell, said in a statement.
Currently, there is no cure for type-1 diabetes except rare pancreatic cell transplants done under what is known as the Edmonton Protocol, involving transplanting pancreatic cells from cadavers into the liver.
But these transplants are fragile and it takes several donors to make one transplant.
Researchers are also looking to stem cell therapies, including embryonic stem cells, as a way to have a more ready supply of cells to transplant.
Heimberg decided to see if they could get the body's own progenitor cells to make beta cells under abnormal circumstances, such as significant injury.
STRESS AND INFLAMMATION
His team clamped off a duct that drains digestive enzymes from the pancreas in laboratory mice. This led to a doubling of beta cells in the pancreas within two weeks.
These animals began to produce more insulin, suggesting the new beta cells were working. Heimberg suspects the cells began to regenerate as part of an inflammatory response.
He said the study suggests that progenitor cells exist in the adult pancreas of mice and they can be induced to make new insulin-producing cells.
Now scientists must look for these same cells in human adults, and find a way to activate them that does not involve injury to the pancreas.
But if they could figure out how to generate large numbers of beta cells this way, they might be used as beta-cell transplants.
"The most important challenge now is to extrapolate our findings to patients with diabetes," he said.
But, he added, "There is a long way to go before we can talk about a potential cure."
Type-1 diabetes affects an estimated 5 to 10 percent of the 20 million Americans with diabetes. Also called juvenile diabetes, it has different causes from the more common type-2 diabetes that is linked with obesity, poor diet and a lack of exercise.
Type-1 diabetes is an autoimmune disease, caused by the mistaken destruction of insulin-producing cells. Most type-1 diabetics must take insulin daily to control their blood sugar levels.
(Editing by Maggie Fox and Cynthia Osterman)