Tue Apr 27, 2004
WASHINGTON (Reuters) - Genetically engineered cells helped revive brain activity of Alzheimer's patients when surgically implanted in their brains, U.S. researchers reported on Tuesday.
The experiment involved eight volunteers with early-stage Alzheimer's disease and was meant to show only that the technique was safe.
But their brains showed increased activity afterwards and the disease seemed to progress more slowly in some, the researchers told a meeting of the American Academy of Neurology in San Francisco.
"These results are intriguing," Dr. Mark Tuszynski said in a statement. "If these effects are borne out in larger, controlled trials, this could be a significant advance over existing therapies for Alzheimer's disease."
Alzheimer's is the most common cause of dementia and affects an estimated 4 million Americans. Incurable and always fatal, it begins with mild memory loss and progresses in a few years to leave patients virtually helpless.
Medications can help delay its progression, but not for long.
For their experiment Tuszynski and colleagues at the University of California, San Diego first took skin samples from their patients.
Then they genetically modified these skin cells to make them produce extra nerve growth factor, a protein that prevents cell death and stimulates cell function.
EARLIER EXPERIMENT ON MONKEYS
They implanted these boosted cells into a brain region where cells degenerate in Alzheimer's disease. They targeted the cholinergic system, which is important in memory and cognitive function.
A similar experiment in old monkeys restored atrophied brain cells to near-normal size and number, and restored connections between the brain cells, Tuszynski said.
A year after surgery, most of his human patients seem healthy with no adverse effects, Tuszynski told the meeting. One patient died of a heart attack five weeks later although the researchers do not know if the surgery was related.
That patient and another moved during the surgery and suffered bleeding in the brain, Tuszynski said.
The six who successfully completed surgery had a 50 percent reduction in their annual rate of decline on one measured cognitive test.
Positron emission tomography, a type of brain scan that shows cell activity, suggested increased metabolic activity in the areas of the brains that got the new cells.
An autopsy of the patient who died showed active nerve growth factor production in the brain, and showed the brain cells in the area where the new cells had been injected had grown.