- The Washington Times - Saturday, June 7, 2008

Massachusetts researchers have discovered molecules in the brain that turn brain stem cells on and off, while Australian researchers used adult stem cells from the nose to create dopamine-producing brain cells in rats - two discoveries that could give hope to people with brain diseases like Parkinson’s.

Scientists at the Harvard Medical School, found that in areas of the brain where stem cells were “sleeping” or not functioning, brain cells called astrocytes were producing high levels of two molecules: ephrin-A2 and ephrin-A3.

When the researchers removed the ephrin molecules, the sleeping stem cells were activated and turned into neurons and other types of brain cells. The study, published this week in the Proceedings of the National Academy of Science (PNAS), was conducted in healthy mice.

“I think this is really exciting,” said researcher Harvard and a scientist at the Institute who led the study.

Only two areas of the brain activate stem cells to turn into neurons, she said, though “sleeping” stem cells are found all over the brain.

Her team also found that astrocytes in one of these active areas release a protein called sonic hedghoc, she said, and when this protein is injected into the brain, this also causes the stem cells to divide and form neurons.

These discoveries could open up potential new areas of treatment for patients with brain diseases that kill neurons and destroy function.

“It means we can probably provide drugs there to try and activate those stem cells and replace the lost neurons and restore function,” she said, adding that the next step is to test their theories on mice with Parkinson’s.

Meanwhile, researchers at Australia, harvested adult stem cells from the noses of Parkinson’s patients and injected them into the brains of rats that had symptoms similar to Parkinson’s.

Researchers had induced the rats’ symptoms by creating lesions on their brains, which made them run in circles. After nose stem cells were introduced, however, the rats eventually stopped running in circles and tests revealed the presence of dopamine in their brains, which researchers said was brought on by the stem cells.

National Centre for Adult Stem Cell Research, said he took the stem cells from the olfactory nerve in the nose because they are “naive,” meaning they “can still be influenced by the environment they are put into.” In this case, the brain.

Parkinson’s disease is a progressive disorder of the central nervous system caused by the degeneration of neurons in one area of the brain, which results in decreased dopamine levels, according to the American Parkinson Disease Association Inc.

Mr. Mackay said there are drug therapies for Parkinson’s that replace dopamine in the brain, but they can become less effective after prolonged use.

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