Naturally occurring molecule shows benefit for Parkinson’s
N-acetylcysteine (NAC), a naturally occurring molecule that replenishes one of the body's antioxidants, shows potential benefit as part of a standard course of treatment for patients with Parkinson's disease, according to a new study published in the journal Clinical Pharmacology & Therapeutics.
Current treatments for Parkinson's disease are generally limited to temporarily replacing dopamine in the brain along with medications designed to slow the progression of the disease. The destruction of dopamine nerve cells in Parkinson's disease appears to result in large part due to oxidative stress, which lowers levels of glutathione, a chemical produced by the brain to counteract oxidative stress. NAC is an oral supplement and comes in an intravenous form that is used to protect the liver in acetaminophen overdose. Several initial studies have shown that NAC administration increases glutathione levels in the brain, but it has not been tested whether such an effect would augment dopamine levels as neurons recover function.
The study, performed by the Department of Integrative Medicine and Nutritional Sciences, as well as the Departments of Neurology and Radiology, at Thomas Jefferson University, advanced earlier findings that NAC may increase dopamine function in patients with Parkinson's disease. In the study, 42 patients with Parkinson's disease continued their current treatment and were placed into two groups: the first group received a combination of oral and intravenous (IV) NAC for three months, in addition to their current treatment program; and the second group, the control patients, received only their standard-of-care Parkinson's treatment for three months. Those patients in the active group received 50mg/kg NAC intravenously once per week and 500mg NAC orally two times per day on the non-IV days.
Patients were evaluated clinically using the Unified Parkinson's Disease Rating Scale (UPDRS), which assesses a variety of symptoms including both cognitive and motor function. Patients also underwent brain scanning using DaTscan SPECT imaging which measures the amount of dopamine transporter in the basal ganglia, the area most affected by the Parkinson's disease process. This test was used to determine the level of neuronal recovery. Patients were evaluated initially and after three months of either receiving the NAC or standard of care therapy, according to the study abstract.
The study found improvements in dopamine levels, the primary neurotransmitter that is specifically decreased in Parkinson's disease, as well as improvements in clinical evaluations of the patients' mental and physical abilities. Compared to controls, the patients receiving NAC had improvements of 4-9 percent in dopamine transporter binding and also showed improvements in their UPDRS score of about 14 percent.
The investigators hope that this research will open up new avenues of treatment for Parkinson's disease patients, according to Andrew Newberg, MD, corresponding author and professor and director of research.
"This is an exciting study that suggests a natural molecule such as NAC can help improve dopamine function and symptoms in Parkinson's patients," he said.