Stem cells from the lining of a woman's uterus transformed into brain cells when they were injected into mice whose brains had damage resembling Parkinson's disease, researchers reported on Thursday.

The findings suggest that women with Parkinson's could serve as their own stem cell donors, the team at Yale University School of Medicine in Connecticut said.

And because the cells are easy to find, banks of tissue-matched endometrial stem cells could be set up, they said.

"Endometrial tissue is probably the most readily available, safest, most easily attainable source of stem cells that is currently available. We hope the cells we derived are the first of many types that will be used to treat a variety of diseases," said Yale's Dr. Hugh Taylor.

"I think this is just the tip of the iceberg for what we will be able to do with these cells," added Taylor, whose findings are published in the Journal of Cellular and Molecular Medicine.

Stem cells are the body's master cells. There are many types but so-called adult stem cells, like those found in the endometrial lining the uterus, are partly "differentiated" into specific tissue types.

For some reason the endometrial stem cells generate less of an immune system rejection response than other stem cell stypes, Taylor's team said. And women shed them naturally every month when menstruating.

Parkinson's disease is considered a good candidate for stem cell treatment. It is caused by the destruction of brain cells that produce dopamine, an important message-carrying chemical involved in movement.

Patients suffer progressively worse tremors and can become paralyzed. There is no cure.

Researchers hope it may be possible to replace these cells and have tried various treatments, including cells from human and pig fetuses. Stem cells are another possible source.

The Yale team generated stem cells from nine women who did not have Parkinson's disease and transformed them in the lab into dopamine-producing nerve cells like those in the brain.

They also injected them directly into the brains of mice with a Parkinson's-like condition and showed that they developed into dopamine-producing cells.

The next step will be to show the cells diminished the symptoms in the mice.