Stem cells reduce Parkinson's symptoms in lab rats

By Colin Nickerson, Globe Staff

In research that illustrates the vast medical potential of new "reprogrammed" stem cells, researchers at the Whitehead Institute for Biomedical Research have used such cells to alleviate symptoms of Parkinson's disease in rodents.

The work, published today in the journal Proceedings of the National Academy of Sciences, has political as well as medical significance. Reprogrammed cells are created from ordinary tissue without harming embryos. The work at the Whitehead, a Cambridge-based center loosely affiliated with MIT, was done with mice and rats, but the principle applies to humans.

"This shows that [reprogrammed] cells are able to function in the therapeutic manner that people have ascribed to them," said Rudolf Jaenisch, the pioneering MIT stem cell scientist who lead the work. "These cells are more readily available and much less controversial than embryonic stem cells."

In the study, rats whose midbrains were damaged in a way to closely mimic Parkinson's received transplants of healthy neurons cultivated from reprogrammed stem cells, which are basically biological "blank slates" that can be turned into nerves, organs, bloods, bone, or any other cell type.

The brain-damaged rats had wandered in uncontrollable circles. After treatment with grafts of healthy neuron tissue, however, eight of the nine test rats "showed markedly less or even no circling," said Marius Wernig, a Whitehead researcher and lead author of the study.

"This is the first demonstration that reprogrammed cells can integrate into the neural system or positively affect neurodegenerative disease," Wernig said.

Jaenisch's lab has already achieved success in using reprogrammed cells to treat sickle cell anemia, a blood disease, in lab rodents.

Last year saw a series of breakthroughs in the creation of stem cells without making or destroying human embryos, winning applause from religious conservatives who had opposed the use of stem cells derived from cloned or frozen embryonic tissue.

The research from the Whitehead offers dramatic evidence that so-called IPS cells -- for induced pluripotent stem cells -- hold medical potential equal to the fanfare that greeted their appearance as an alternative to embryonic stem cells, although human treatments remain far off.

"This is a big step forward," said Margaret Sutherland, a program director at the National Institute of Neurological Disorders and Strokes. "IPS cells are still in their infancy. But this shows their use [in human medicine] could be near for things like drug screening'' or in diagnosing patients.

Researchers concede that the direct therapeutic use in humans remains problematic because the reprogrammed cells are forged from ordinary tissue such as skin cells by a technique that relies on potent regulator genes that are linked to cancer.