Islets of youth  pg. 2

Injections of these so-called induced pluripotent stem (iPS) cells have been shown to improve symptoms of sickle cell anemia and Parkinson’s disease in experimental mice and rats.

Last year also provided evidence that the pancreas can be “coaxed” into repairing itself.

A team of Belgian and French researchers reported that, with the help of a factor called neurogenin3, injured adult mouse pancreas can generate new beta cells from immature “progenitor” cells.

Maureen Gannon, Ph.D., in her Vanderbilt lab. Behind her, from left: graduate student Kathryn Henley, research assistant Christine Pope, and Magda Bokiej, a student in the Medical Scientist (M.D./Ph.D.) Training Program.
Photo by Anne Rayner
“Everybody had been thinking for the past several years that … you wouldn’t make any new ‘baby’ insulin-producing cells from a progenitor,” says Vanderbilt developmental biologist Maureen Gannon, Ph.D. “And now there’s evidence that you can reactivate that program. That, to me, is really exciting.”

These findings are “hugely radical, unpredicted,” Magnuson adds. “They change the paradigm about the plasticity of every cell in the body … (implying that) you can follow the developmental path, go way back to the beginning and then come forward to whatever cell you like.”

Underlying problem

Reprogramming a patient’s cells to produce insulin would provide a welcome alternative to transplanting pancreatic tissue from other human or animal donors, a procedure limited both by the lack of donor tissue and by the need to suppress the patient’s immune system to prevent transplant rejection.

It also could avoid the need to harvest another, more controversial source of stem cells, those derived from human embryos.

However, the virus used by the Japanese scientists to insert the “reprogramming” genes also triggered formation of tumors in mice. “This is not a trivial issue,” cautions Alvin Powers, M.D., a leader in the study of pancreatic biology and islet transplantation who directs the Vanderbilt Diabetes Center.

And even if the pancreas can be induced to generate new beta cells, or if skin cells could be “re-programmed” to produce insulin, that does not solve the underlying problem of type 1 diabetes – a misguided attack by the body’s immune system that destroys the beta cells.

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