Stem cells may help type 1 diabetes patients start over

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Stem cells may help type 1 diabetes patients start over

A diagnosis of type 1 diabetes comes with a lifelong burden of new responsibilities: regular monitoring of blood sugar levels, careful adherence to strict diet and exercise regimens, and daily insulin injections.

Researchers hope to ease the burden by developing new treatments for type 1 diabetes — treatments that might one day even cure the disease.

One promising area is stem cells. City of Hope researchers believe they may be able to engineer them into new cells that produce insulin. These new cells would replace islet cells, the insulin- producing cells in the pancreas that are destroyed in type 1 diabetes.

Adult stem cells from human bone marrow can mature into cells resembling islet cells when placed within pancreas tissue, according to research by Chu-Chih Shih, Ph.D., assistant professor in the Division of Hematology & Hematopoietic Cell Transplantation.

Shih published the findings in the journal Stem Cells and Development in October 2007.

Scientists are looking for a variety of ways that would allow the body to keep producing insulin despite type 1 diabetes. City of Hope researchers, for example, perform islet cell transplants, investigative procedures in which surgeons transfer islet cells from a deceased donor into patients with diabetes. But supplies of donated islet cells are limited.

Shih believes the stem cell strategy could relieve pressure to collect much- needed islet cells from relatively few cadaveric donors. “There have been only 2,000 pancreatic donors, but there are millions of patients with diabetes,” Shih said. “Stem cell therapies could supply alternative sources of cells that can differentiate into pancreatic islet cells, which would benefit most patients with diabetes.”

Shih and his colleagues began by asking whether a type of human stem cell could form islet-like cells. The researchers labeled these stem cells with a green tracer dye and then injected them into human pancreas tissue that had been transplanted onto laboratory mice.

“Four months later, we harvested tissue and saw green cells, meaning that the stem cells survived,” Shih said. “But the important question was, did they produce insulin?”

Not only did they produce insulin, but they pumped it out in proportion to the amount of the blood sugar glucose they were exposed to, just like islet cells would.

Insulin is the hormone that signals the body’s cells to absorb glucose. Cells need glucose for energy. But without insulin around, glucose simply stays in the bloodstream and cells cannot absorb it.

The group also reported another remarkable finding: When they transplanted these cells into laboratory mice engineered to have type 1 diabetes, the transplant relieved diabetes symptoms.

“Basically this experiment proves that the green islets derived from the stem cell graft are physiologically functional — that they are as good as the islets you would purify from the pancreas,” Shih said. He cautions that researchers are several years away from trying these therapies in humans.

Of the more than 20.8 million people with diabetes in the united States, 5 to 10 percent have type 1. Although it can develop at any age, type 1 diabetes most commonly appears in children and young adults. One in every 400 to 600 children has been found to have the disease.

The National Institutes of Health, the Ella Fitzgerald Charitable Foundation, the California Community Foundation and The Rosalinde and Arthur Gilbert Foundation funded the research.