Source: Deseret News

By John Lauerman

Stem cells from adult human bone helped mice with diabetes make insulin, suggesting new treatments for the disease that afflicts millions of Americans, scientists said Monday.
      
Injections of the adult stem cells increased insulin levels in about 30 mice with diabetes, a disease that destroys blood sugar control and leaves people vulnerable to lethal complications, said Darwin Prockop, director of the Center for Gene Therapy at Tulane University Health Sciences Center in New Orleans, who co-wrote the study.
      
About 3 million of the 21 million Americans with diabetes suffer from the Type 1 form that occurs when the body's own immune system attacks insulin-making cells in the pancreas. Injections with bone marrow stem cells may help revive the damaged pancreas, and perhaps help patients avoid kidney, heart and eye disease, Prockop said.
      
"It's just become apparent over the past year that these bone marrow cells are stemlike and that there are several ways they can repair tissues," he said Monday in a telephone interview. "The results may be dramatic."
      
The ability of stem cells to mature into many cell types suggests they may be able to treat diabetes, Alzheimer's disease and other conditions resulting from damage to important tissues. Research on adult stem cells has gained importance since 2001 when President George W. Bush restricted government funding for work on human embryonic stem cells.

Embryonic vs. adult
      
Embryonic stem cells are retrieved from embryos that are several days old. Adult stem cells can come from the tissue of aborted fetuses, umbilical cord blood, or living children and adults. While easier to access, since they can be extracted from living tissue, they are able to take on fewer cell types than embryonic stem cells.
      
The research, led by Tulane gene therapy researcher Ryang Hwa Lee, will be published this week in the Proceedings of the National Academy of Sciences journal. The study was done with about 30 mice given a chemical that damaged their pancreases, making them diabetic, he said.
      
After the damage occurred, the mice's pancreases began to fail, so that they almost completely stopped making insulin, and their blood sugar levels began to skyrocket. In people, chronic high blood sugar levels are linked to vision loss, kidney failure, heart attacks and other severe complications that often strike people with diabetes.

Heart to pancreas
      
Prockop's team injected the adult bone marrow stem cells, which have the ability to mature into several types of cells, into the mice's hearts. Using a genetic marker, he found that the cells had traveled to the pancreas in about two weeks.
      
At that point, the mice's blood sugar levels began to fall to about half that reached before treatment. In addition, the mice were making increased levels of mouse insulin, rather than human insulin.

That suggested that the human cells were contributing to the repair of the mouse pancreas, Prockop said. His studies have shown that stem cells can "loan" energy-producing structures called mitochondria to other, sick cells.
      
"These cells are remarkable," he said. "They're part of a natural repair system we all have, and all we're trying to do with our strategy is increase their levels."    

Researchers noted in a series of studies published Sept. 21 in the New England Journal of Medicine that adult bone-marrow stem cells can increase pumping power in damaged human hearts. Those studies have also shown that the stem cells themselves don't begin growing heart muscle, and researchers have theorized that they somehow contribute to tissue repair.

Kidney repairs
      
Prockop noted that the stem cells also traveled to the mouse's kidney. The kidney also showed signs of repair, with lower levels of immune cells called macrophages that repair infections, and a healthy thickening of tissue between kidney cells.
      
Companies including StemCells Inc. and Aastrom Biosciences Inc. are developing treatments for a variety of diseases using adult stem cells. Prockop said he is applying for Food and Drug Administration permission to test take human bone marrow cells, grow them in a dish, and inject them into people with diabetes.
      
"We think the dangers are minimal," he said. "We may be able to repair the eyes, heart, brain and peripheral circulation."