"The study was designed to test the hypothesis that high doses of coenzyme Q10 would slow the progression of Parkinson's, as measured by movement difficulty or disability," says Ray Watts, M.D., professor of neurology, Emory University School of Medicine, and lead investigator of the Emory study. "We are very encouraged with the results of this small trial, which consisted of 80 Parkinson's patients nationwide. However, a larger, multi-centered, controlled trial is still needed before this treatment can be recommended to patients with a high degree of certainty."
Parkinson's disease is a progressive disorder of the central nervous system affecting over one million people in the United States. Symptoms include tremor, slowness of movement and stiffness of muscles. Although certain medications, such as levodopa or L-dopa, can reduce the symptoms of PD, they do not slow the progressive deterioration in function.
Scientific evidence shows that mitochondrial function is impaired in Parkinson's disease patients. Mitochondria produce energy for the cells. Research also shows that levels of coenzyme Q10, which the body uses to aid in energy production, are reduced in the mitochondria of PD patients. In animal models of PD, scientists have determined that coenzyme Q10 supplements can protect the part of the brain affected by the disorder. "Because of these findings, we've learned that supplementation of this nutrient, which is often described as an antioxidant, plays a role in helping mitochondria to function better and boost energy production in the cells of PD patients," says Dr. Watts.
At Emory, eight Parkinson's disease patients took part in this study, which ended in May 2001. They, like the rest of the participants nationwide, were randomly selected to receive high doses of coenzyme Q10 (300, 600 or 1200 mg/day) or a placebo four times a day. Participants had to be in the early stages of the disease (one to three years following diagnosis) where medications, such as L-dopa, were not yet needed for treatment. Because the participants were only taking coenzyme Q10 and no other drugs, researchers felt they were able to produce very pure results of the effects of this nutrient. Participants remained in the trial for a maximum of 16 months, or until they needed medications to treat the symptoms of the disease.
Participants were evaluated and a number of clinical tests were performed prior to and during the study to rate their motor abilities, activities of daily living, mental function and mood. To determine the participants' progress, researchers used the Unified Parkinson Disease Rating Scale, which evaluates a patient's abilities through a battery of tests, using a scale of zero-four. Lower scores reflect less impairment and better function. At the halfway mark of the study, the scores among the four groups clearly showed a difference. The groups taking the lowest and intermediate dosages (300 and 600 mg/day) had equivalent or lower scores than the placebo group, while the scores for the group receiving the highest dosage (1200 mg/day) were substantially lower. This pattern of disability reduction continued until the end of the study. The benefit was seen in assessment of mental function and mood, activities of daily living and motor skills.
"This is a very important study with positive results for Parkinson's patients," says Dr. Watts, a world-renowned Parkinson's disease researcher. "But we are not at the stage yet where we feel comfortable telling patients to go to their local health food store and purchase coenzyme Q10 as a treatment for the disease. Right now, we know this study shows vitamin-type therapy may slow the progression of movement and motor disabilities associated with the disease, but more studies are needed to determine the true effects of the compound. Emory will be involved in some larger coenzyme Q10 studies in the near future, in hopes of finding out these specific effects." Researchers found no safety or tolerability concerns or problems with the administration of coenzyme Q10.
Jorge Juncos, M.D., associate professor of neurology, Emory University School of Medicine, served on the national steering committee for this study, helping to research and write the paper.
Ten centers, including Emory, took part in this study, which was funded by the National Institute of Neurological Disorders and Stroke of the National Institutes of Health. All centers are members of the Parkinson Study Group, a non-profit, North American organization consisting of Parkinson's disease and movement disorder specialists.
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