New Genetic Graft Eases Symptoms in Rats

UC San Diego researchers report that they can alleviate the symptoms of Parkinson’s disease in rats by grafting genetically engineered skin cells into the animals’ brains.

Their technique may drastically reduce some of the ethical difficulties associated with a controversial new therapy for the disease that involves grafting brain cells from aborted fetuses into the brains of Parkinson’s victims.

Parkinson’s is caused by the death of brain cells that secrete the neurotransmitter dopamine, which plays a key role in the control of muscle movements.

In an effort to replace the lost dopamine, surgeons have grafted both tissue from the adrenal glands, which also secrete dopamine, and brain tissue from aborted fetuses into the brains of about 300 Parkinson’s victims.

But grafting adrenal tissue requires two operations--one to remove the tissue from its normal location over the kidney and one to implant it--and the use of fetal tissue has become inextricably entwined with the debate over abortion. Federal rules now prevent the use of fetal tissue in government-funded research or therapy.

Neuroscientist Fred H. Gage and his colleagues at UCSD have circumvented these problems by genetically altering rat skin cells so that they secrete dopamine, then implanting the cells into the brains of rats in which dopamine-secreting brain cells had been destroyed. Because the cells were destroyed on only one side of the brain, the rats’ muscle control was impaired on one side of their body and they walked in circles.

Gage and his colleagues reported in the latest Proceedings of the National Academy of Sciences that the genetically engineered cells reduced the Parkinson-like symptoms by 40%. The altered cells are “nowhere near as effective as fetal cells,” Gage said, but he believes that their efficacy can be greatly improved. Most important, he added, the approach offers a “viable alternative” to the use of fetal cells.