Insulin-producing pancreatic cells are replenished by d...( Howard Hughes Medical Institute (HHMI) ...)

Although the experiments, which were done using mice, do not rule out the possibility that there are adult stem cells in the pancreas, the researchers say that they do suggest strongly that embryonic stem cells or mature beta cells may be the only way to generate beta cells for use in cell replacement therapies to treat diabetes.

The research team, which was led by HHMI investigator Douglas A. Melton at Harvard University, reported its findings in a research article published in the May 6, 2004, issue of the journal Nature. Melton's co-authors include Yuval Dor, Juliana Brown and Olga I. Martinez, all of Harvard.

In cell culture, embryonic stem (ES) cells retain the properties of undifferentiated embryonic cells. ES cells have the capacity to make all cell types found in an adult organism. One of the most hotly debated questions in biology is whether adult stem cells, which have been isolated from blood, skin, brain and other organs, have the same developmental capacity as ES cells.

Researchers have known for some time that ES cells can give rise to pancreatic beta cells during development. "But the more interesting question for us has been what happens in mature pancreatic tissue to both maintain the pancreas and to regenerate it," said Melton. "Previous studies have suggested that there are sources of adult stem cells that might give rise to beta cells. However, those studies had largely depended on histological 'snapshots' of tissues." Those snapshots can only suggest the "geographic" origin of new beta cells and not the identity of the cells from which they arise, Melton noted.

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Contact: Jim Keeley
keeleyj@hhmi.org
301-215-8858
Howard Hughes Medical Institute
5-May-2004