Embryonic Stem Cells Repair Rat Brains

By Daniel DeNoon

From: WebMD

Jan. 7, 2002 — In a potential breakthrough for Parkinson’s disease, Harvard researchers have found that early embryo cells can fix the brains of animals with the disease.

Even with luck and a lot of hard work, it will be five to 10 years before this is ready for human tests. Still, the finding is a giant step forward. It points the way to treating — and maybe curing — Parkinson’s patients with stem cells grown in laboratories. Such cells already exist.

“Our goal has been to get stem cells to develop into particular kind of cells — the cells damaged in Parkinson’s disease,” study leader Ole Isacson, MD, PhD, tells WebMD. “Now we have done this.”

Isacson directs the Udall Parkinson’s Disease Research Center and the Neuroregeneration Laboratory at Harvard University. He and co-workers reported the findings in the Jan. 8 issue of the Proceedings of the National Academy of Sciences.

The study shows that cells taken from mouse embryos turn into brain cells when placed in rat brains. They don’t just sit there: they hook up to the brain and work like normal brain cells.

In Parkinson’s disease, certain brain cells die off. These are the cells that make dopamine, an extremely important chemical messenger that helps nerves communicate. It is involved in many bodily activities, including movement. If researchers kill dopamine cells in live rats, the animals lose the ability to move properly — just like people with Parkinson’s disease. When Isacson and co-workers gave these rats transplants of mouse embryo cells, they regained norEN??movement.

“We’ve shown that the stem cells develop into brain cells with all the characteristics of normal dopamine cells,” Isacson says. “Furthermore, we’ve shown that the cells secrete dopamine in response to the proper signals — and that this results in behavioral changes.”

Neurologist William C. Koller, MD, PhD, director of the Parkinson’s Disease Center at the University of Miami, Coral Gables, Fla., calls the results a major finding.

“This is a big step forward,” Koller tells WebMD. “It is proof of concept that this can eventually work in people. It is a pretty big deal.”

Earlier studies showed that transplants of fetal brain cells could help people with Parkinson’s disease. But these cells didn’t work very well, Koller says. They were already too highly developed to hook up with patients’ brains.

Early embryonic cells don’t have this problem. That’s because they come from recently fertilized eggs. They are so basic that they can be transplanted without rejection by the immune system. One of the Isacson team’s major findings was that these cells — when separated from each other — grow into brain cells all by themselves.

“This is one of the most elegant biological things I have ever seen,” Isacson says.

There’s a lot of daunting work ahead. One problem is that the embryonic cells become different kinds of brain cells. Isacson’s team is working on a way to get even more of them to become the specific kind of brain cell that Parkinson’s patients need.

“I am very passionate about getting this to the patients, but there are technical issues to solve,” he says. “Just having a rocket doesn’t mean you can go to the moon. Our work convinces me that one day we can transplant these cells to patients. To get there requires a lot of technical and biological research. It is an enormous effort to make these things move forward.”


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