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Japan-U.S. Team Succeeds in Mass Producing Insulin-Making Cells to Treat Diabetes

Posted on: Tuesday, 27 September 2005, 18:00 CDT

Tokyo, Sept. 27 (Jiji Press)--A Japan-U.S. medical research team has developed a method to mass produce insulin-secreting cells for transplantation to type 1 diabetic patients, who suffer from a genetic condition that prevents the pancreas from secreting the blood sugar-controlling substance.

This is "one step toward a potential cure of diabetes by transplantation," the researchers said in their report published in the latest edition of the Nature Biotechnology magazine.

It is known that type 1 diabetes, which is also called insulin dependent diabetes, is caused by the destruction of insulin- producing pancreatic beta-cells by wrongfully programmed autoimmune responses.

Because no insulin is secreted, people with type 1 diabetes require insulin injections several times a day to keep blood sugar at normal levels. If sugar levels are not controlled, various complications such as retinopathy-caused blindness, kidney failure and peripheral nerve disorder can occur.

But the insulin injection treatment is a burden on diabetics and lowers their quality of life, which is why pancreas transplantation has been regarded as the most promising way to cure the disease. 0ne big problem for organ transplantation therapy, however, is the serious shortage of donors.

To resolve the donor problem, the researchers, including those from Japan's Okayama University and the Rosalind Franklin Comprehensive Diabetes Center of the United States, favored the idea of giving patients cultured insulin-producing b-cells instead of transplanting entire pancreas.

The pancreatic cell transplantation therapy is not a new idea, with some researchers already trying to make a b-cell line in vitro from embryonic and stem cells, which have the potential to develop into various tissues. But experiments using stem cells have so far failed to yield favorable results, as the b-cells hardly increased.

In view of the failures, the Japan-U.S. team tried to achieve continued b-cell expansion by developing a method of immortalizing the cells.

"Our strategy was to transform human primary b-cells with immortalizing genes and screen for clones that were not tumorigenic and that expressed insulin and b-cell-associated factors," the group said. "We now report that our reversibly immortalized pancreatic b- cell clone secretes insulin in response to glucose stimulation..."

In addition to nonstop expansion of the cell line, the researchers confirmed that transplantation of the cells resulted in "perfect control of blood glucose" in diabetic mice, which were kept healthy for longer than 30 weeks.

"This cell line offers continuous availability, uniformity and sterility, and may provide a source of b-cells for the treatment of type 1 diabetic patients by transplantation," the group concluded.END

Source: Jiji Press English News Service

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