Diabetes Reversed In
Mice With Stem Cells -
Human Tests Next
By Maggie Fox
Reuters Health and Science Correspondent
WASHINGTON (Reuters) - Scientists says they have used stem cells -- "master cells" that are the source of new cells in the body -- to reverse diabetes in mice.
They said their experiment is a first demonstration that the cells are as valuable as people had said they would be in treating disease.
The team, at the University of Florida in Gainesville, said it has already started testing human cells in the laboratory and think they will work, too.
Stem cells have been in the headlines since their real potential was discovered just over a year ago. Researchers said they could be used as tissue transplants, or even as a source to grow whole new organs.
Blood stem cells are routinely used to replenish the bone marrow of cancer patients when chemotherapy or radiation therapy destroys it. The other stem cells are elusive, but have been identified in the brain, muscles and various organs.
One example that comes up over and over again from those who are pressing for more stem cell research is its potential to treat diabetes.
Dr. Ammon Peck and colleagues at the University of Florida say they have finally shown it.
Writing in the journal Nature Medicine, they said they isolated stem cells from the pancreases of mice, got them to grow, transplanted them into diabetic mice and showed they worked to produce insulin.
Type-I or juvenile diabetes is caused when a person's immune system mistakenly turns against insulin- producing cells and destroys them. They no longer produce enough insulin to control levels of blood sugar and must take insulin daily.
About 10 percent of the estimated 16 million Americans with diabetes have type-I diabetes.
Scientists have tried to transplant the insulin-producing islet cells, but the method does not work well and the cells are scarce. When stem cells were discovered the hope was that they could be used instead.
"To reverse diabetes, you need to either take a transplant of the whole pancreas or the islets," Dr. Desmond Schatz, a professor of paediatrics and a diabetes expert at Florida, who worked on the experiment, said in a telephone interview.
"Here the potential is you can take stem cells, grow them up, and they grow into islets that are capable of reversing disease."
Schatz said scientists had known that the islet cells come from cells known as pancreatic ductal epithelial cells.
They took some of these cells and grew them in a culture.
No one really knows what a stem cell looks like. Scientists only know of their existence because of their final product -- more cells. So Schatz's team just hoped they would get stem cells, and they did.
In laboratory dishes the cells seemed to produce insulin in response to sugar, so they implanted some in mice specially bred to develop diabetes.
"We were able to show a reversal of the (diabetes) for a short period of time," Schatz said. They killed their mice to look at the cells, so they do not know how long the effects would have lasted.
But the cells they looked at seemed to be normal islet cells.
"The next step is take this into humans," Schatz said. "In preliminary experiments it appears that we can take human pancreatic duct cells and show that they can differentiate into islet cells as well."
Schatz said the source of the stem cells was organ donors -- people who have died of various causes and donated their organs.
"This paper emphasises the enormous potential of stem cell therapy," David Sachs and Susan Bonner-Weir of Joslin Diabetes Centre in Boston said in a commentary.
One of the controversial sources of stem cells is early embryos -- usually left over from attempts to make test-tube babies. Schatz said if organ donors can be used as a source, "you could potentially bypass (the need for) embryonic cells."
In a second study in the same journal, Steven Goldman and colleagues at Cornell University in New York said they had found a place in the adult brain that might serve as a source of neural stem cells.
They described a method to identify and isolate cells from the adult human dentate gyrus section of the hippocampus and said these might be used for brain cell transplants, perhaps to treat patients with Parkinson's or other diseases caused by brain degeneration.


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