CHICAGO, Oct 02 (Reuters Health) - A newly identified brain chemical may someday allow physicians to diagnose and treat Parkinson's disease much earlier, according to a small preliminary study at the University of Saskatchewan in Canada.
Drs. Yulin Deng and Ali M. Rajput said the chemical, ADTIQ, was highly concentrated in the brains of four Parkinson's patients who had died. Three patients without Parkinson's had much lower brain levels of ADTIQ.
Based on this small sample, Rajput said ADTIQ could potentially serve as an early biological marker for Parkinson's--a disease for which there is currently no biological test.
"If we can find a way to measure this substance in the blood, spinal fluid or urine, then we can diagnose Parkinson's disease early," Rajput said, adding that if the disease can be caught early, doctors and patients may be better able to manage it.
Rajput told the annual meeting of the American Neurological Association that the build-up of ADTIQ in the brain of Parkinson's patients may be caused by an error in metabolism. ADTIQ may be a toxic byproduct of this error.
Parkinson's disease, which afflicts about half a million Americans, is marked by the progressive death of nerve cells in certain areas of the brain. This creates a shortage of cells that produce the chemical dopamine, which helps control movement. These diminishing dopamine levels cause the typical symptoms of Parkinson's disease, which include muscle rigidity and tremor.
Conventional drug treatment involves replacing the lost dopamine, but this does not replace patients' lost nerve cells or stop the progression of Parkinson's.
Copyright © 2001 Reuters Limited. All rights reserved. Republication
or redistribution of Reuters content, including by framing or similar means,
is expressly prohibited without the prior written consent of Reuters. Reuters
shall not be liable for any errors or delays in the content, or for any
actions taken in reliance thereon. Reuters and the Reuters sphere logo
are registered trademarks and trademarks of the Reuters group of companies
around the world.
BOSTON, Sept. 27 (UPI) --
Preliminary laboratory studies suggest the antidepressant bubroprion may help slow the degenerative Parkinson's disease, but whether the approach works in humans remains to be seen.
Researchers at Boston University Medical Center used slices of rat brain
tissue to test whether bubroprion, used to help smokers kick the habit
and tested as a weight loss aid, could slow Parkinson's disease.
Dopamine is a brain chemical necessary for transmitting neurological signals. Parkinson's patients have too little dopamine, leading to brain cell destruction that results in a loss of movement and coordination skills. However, cell studies conducted in laboratories indicate dopamine also can have a toxic effect in the brain.
The Boston researchers found rat tissue treated with bubroprion had a dual effect. It blocked dopamine in some areas while aiding the transportation of it in others. "I'm quite excited about this finding," researcher Isabelle Mintz, an assistant professor of pharmacology at Boston University, told United Press International.
"The most promising application would be in people in early (stages of) Parkinson's disease." Mintz also pointed out "not every antidepressant is going to work" on Parkinson's disease.
It is uncertain, however, whether these same effects could be produced in humans, cautioned Dr. Richard B. Dewey Jr., associate professor of neurology and director of the Clinical Center for Movement Disorders at the University of Texas Southwestern Medical School in Dallas.
"This is exciting research because it's another drug class that's being looked at ... and we need that," Dewey told UPI. "(But) we've already been down that route now with two, maybe three (other) drugs in the rat" where initial studies were promising, but failed in humans. Dewey said there are "a lot of drugs that are effective in treating the symptoms in Parkinson's disease, but none that slow down the disease."
The precise cause of Parkinson's and whether it is genetic, environmental or both, is not known. It is estimated about 1 million people in North America have Parkinson's and about 90 percent of those cases are in the United States, according to Dr. Karl Kieburtz, professor of neurology at the University of Rochester in Rochester, N.Y.
There are Parkinson's patients already taking antidepressants to treat depression, not their Parkinson's, Kieburtz pointed out, and although they might not be on bubroprion, he is concerned about linking antidepressant use to combating Parkinson's disease.
"I'd be cautious of making that assertion," Kieburtz said. He added antidepressants are very common and "history is littered in recent past with false hopes." Bubroprion, sold under the brand name Wellbutrin, is made by pharmaceutical giant Glaxo Wellcome.
The study, reported in the Sept. 28 issue of the journal Science, was funded by the National Institutes of Health, the American Parkinson Disease Association and private donations from John Nicholl to Boston University.
(Reported by Katrina Woznicki in Washington)