Scientists here have for the first time successfully grafted brain tissue from healthy to brian-damaged animals to correct a severe movement disorder.
The striking achievement-if it can be repeated in more animals, then, safely, in humans-might lead to a revolutionary new surgical treatment for Parkinson's disease and other human disorders caused by faulty brain chemistry.
An international reserach team led by three scientists of the National Institute of Mental Health, and including others at the University of Colorado and Sweden's famed Karolinska Institute, collaborated in the pioneering work.
The team's report appears in the current issue of Science, weekly journal of the American Association for the Advancement of Science.
The NIMH trio-working in the agency's Laboratory of Clinical Psychopharmacology on the grounds of St. Elizabeths Hospital-consisted of Drs. Mark J. Perlow, William J. Freed and Richard J. Wyatt, the laboratory's director.
First, the group created brain lesions in rats, much like those found in human Parkinsonism, a disease marked by severe tremors and rigid muscles. The scientists destroyed the substantia nigra, a part of the brian stem that plays a key role in producing dopamine-a chemical involved in nerve transmission and one found only in lowered amounts in Parkinsonism.
As a result of the brain damage, limited to one side of the brain to avoid killing the rats, the animals could walk only in circles.
The scientists then removed a tiny part of the brains of rat fetuses, a part containing the darkish substantia nigra. They transplanted this healthy tissue to the damaged rats - to a site near the front of the brain that controls dopamine-mediated movement.
The transplanted tissue grew and was not rejected. The brain is linked only poorly to the immune system that makes the body reject most foreign tissue.
Within a month, the movements in most of the 29 brain-damaged rats improved. There was little improvement in some, but improvement of 50 percent or more in more than half the animals and 70 percent improvement in some.
Improvement was maintained for six months, to a mature age for rats, before the animals were killed.
Human Parkinsonism is often alleviated with the drug L-dopa, a chemical precursor of dopamine. But it can also have severe side effects.
One informed brain scientist, who declined to be named, conjectured yesterday that similar human surgical treatment - of Parkinsonism or other chemically linked brain disorders, like deficiencies of growth hormone - might be possible in 5 to 10 years if the new work pans out in other species and man.
The research team is now working with monkeys. "But there are many steps necessary before we can think of any human applications," said Freed.