USF study advances fetal cell therapy

Researchers find that Huntington's disease, which is otherwise fatal, may be treated therapeutically.

By WES ALLISON

© St. Petersburg Times, published December 1, 2000

TAMPA -- Researchers at the University of South Florida have found that fetal tissue can survive being transplanted into the brains of patients with Huntington's disease, and that the transplanted tissue remains disease-free.

Patients who received the transplants also showed marked improvements in their conditions, suggesting that transplantation of fetal neurons or other cells may one day offer life-changing treatment for people who suffer from Huntington's, a fatal degenerative brain disease that has no cure. It could have applications for other brain and spinal cord diseases as well.

The USF findings are to be published Tuesday in the Proceedings of the National Academy of Sciences, and they generated significant interest in the neuroscience community.

"From this, we can conclude that these grafts will survive, connect with the brain, not be rejected," said Dr. Thomas B. Freeman, medical director of the Center for Aging and Brain Repair at USF and the study's lead investigator.

"Most importantly, we have concrete evidence that a disease that is otherwise fatal . . . finally has the opportunity to be treated therapeutically."

The results were bolstered by nearly identical findings of French researchers that are being released in the British medical journal Lancet. Dr. Christopher A. Ross, chairman of the medical and scientific advisory committee for the Huntington's Disease Society of America, said it's still "highly experimental," but it was encouraging that the genes that cause Huntington's did not invade the transplanted neurons, too.

The neurons are obtained from fetuses aborted in the first trimester. They're taken from the striatum, a central relay station in the brain and then transplanted in the damaged area of the patient's brain.

"The reason this study is important is because it's helping to establish transplants as at least a potentially effective treatment method in degenerative diseases," said Ross, professor of psychiatry and neurology at Johns Hopkins University in Baltimore.

"The fact that you can apply it to Huntington's disease, which is more difficult and the degeneration is more widespread than in Parkinson's, is also significant."

Huntington's disease affects about 30,000 Americans. It causes symptoms like Parkinson's, including loss of motor skills and difficultly speaking, but also can cause psychiatric problems. Unlike Parkinson's, it is genetic, and about half the children of Huntington's patients also will get it.

The USF study continues the national recognition in brain research for the university team, which includes Dr. Paul Sanberg, director of the aging and brain repair center, and Dr. Robert A. Hauser, director of USF's Movement Disorders Center.

Sanberg did the first such transplant in animals in 1983. Seven years ago, the team published a study that showed fetal tissue also survived being transplanted into the brains of Parkinson's patients, and those patients improved.

They applied the same principles to Huntington's, and three years ago they implanted the neurons into the brains of the first of seven patients. One died of a heart attack, which allowed for an autopsy. It showed the neurons had successfully connected in the brain and were thriving, providing a rare glimpse into how the grafts were integrated into the brain.

A sixth patient suffered blood clots over the surface of her brain, part of the normal course of Huntington's, but the remaining five have improved by about 20 percent.

"What we ordinarily would be comparing that with would be a 15 percent or 20 percent decline in a year," Hauser said. "We think it's good news and promising so far."

Meanwhile, French researchers found similar improvements in three of five Huntington's patients implanted with fetal neurons, the Lancet study says.

"Which means that it's less likely to be a fluke," Freeman said.

But he and Hauser were quick to stress that the studies come with several caveats: They were very small, and the results are preliminary. Also, the tissue was grafted to only one region of the brain, but Huntington's -- unlike Parkinson's -- causes degeneration in the entire brain. That means the grafts ultimately might not prevent widespread degeneration.

The use of fetal tissue is strictly limited in the United States and other countries, and it likely will never be used for widespread treatments. However, researchers believe the principle should apply to other diseases and types of cells as well, such as stem cells -- the body's building block cells -- that can be grown in the lab.

"We've now shown that grafts can survive and connect with the brain in two separate diseases that involve two different mechanisms of neurological degeneration," Freeman said. "This gives us hope for other neurological disorders."

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