Scientists have reported that they reversed a Parkinson's-like disease in monkeys by transplanting their tissue into their brains.
The method, reported in the current issue of the journal Neuron, avoids the problems of Parkinson's research using fetal-cell transplants. The cells used by the researchers came from the monkeys' carotid bodies, small organs in the neck.
Fetal cells must be taken from up to 10 discarded fetuses for each treatment to reverse Parkinson, a movement disorder, and full-scale brain surgery is necessary.
The work with the monkeys was done in Spain by Dr. Jose Lopez-Barneo of the University of Seville, Dr. M. Rosario Luquin of the University of Navarre and their colleagues.
Dr. Arnon Rosenthal of the biotechnology company Genentech, who is an expert on transplantation experiments in Parkinson's, said in a telephone interview yesterday that the new approach was far better than using fetal cells. Dr. Rosenthal said the cells used in the experiments produced 35 times more of the key chemical involved in Parkinson's, the neurotransmitter dopamine, than do fetal cells.
The researchers said they would soon begin testing the procedure in four people. Additional experiments have begun in five monkeys. It will take a year or more to determine whether the method is successful.
The Neuron article describes how the carotid cells in each of two monkeys were taken with a simple incision in the neck, then reinserted into the proper spot in the brain by using a very thin needle.
To test treatments for Parkinson's disease, scientists use injections to induce damage in the area of the brain where movement is coordinated. As in Parkinson's disease, the cells there gradually lose their ability to produce dopamine, bringing on symptoms like those of the disease.
The monkeys had artificially induced Parkinson's on both sides of their brains. But the fresh carotid cells were injected on only one side, thus allowing experimenters to compare movement on the animals' two sides after the transplant.
Videotapes of the monkeys in the experiment show marked improvement in hand movement after the transplants. The monkeys are shown doing tasks like reaching through a hole to grab nuts on the other side. Before the new cells were put in, the monkeys had great trouble reaching for and grasping the small nuts.
But after the cells on one side had be inserted, the hand linked to that side of the brain soon was performing normally. The monkeys used lightning jabs with the hand to get and eat four nuts quicker than its other hand could even grasp one.
The artificially induced Parkinson's had clearly been reversed, the researcher said, and the change has continued in the animals for six months after the transplants.