Antioxidant may slow Parkinson's disease

Serum levels of urate in people with Parkinson's disease may indicate how quickly the disease will progress, according to a study published online Oct. 12 by the Archives of Neurology (link).

Researchers examined levels of the antioxidant urate in the serum and cerebral spinal fluid of nearly 800 people with early Parkinson's disease. While the study concluded that higher levels of urate was predictive of a slower rate of disease progression, the study's authors said the findings need to be examined further before doctors use them in clinical practice.

"We don't know if it's the urate or a determinant of the urate that's slowing down the disease," said senior author Michael A. Schwarzschild, MD, PhD, an associate professor of neurology at Harvard Medical School and director of the Molecular Neurobiology Laboratory at the MassGeneral Institute for Neurodegenerative Disease. "Clinicians need to be particularly careful to not recommend raising urate levels on one's own. It shouldn't be attempted outside a well-constructed clinical trial setting in which the potential risks and benefits can be carefully balanced."

For years, epidemiologists hypothesized that higher levels of urate in the blood may protect against neurodegeneration, Dr. Schwarzschild said. Urate levels, which can be elevated through diet or increased intake of fructose and purines, also can become pharmacologically elevated with inosine.

A clinical trial, funded in part by the Michael J. Fox Foundation, is under way to assess the safety of inosine and its ability to raise urate levels in blood and cerebral spinal fluid in individuals with early Parkinson's.

The lack of a definite drug that slows disease progression is one of the greatest hurdles facing doctors treating patients with Parkinson's, said Rajesh Pahwa, MD, a professor of neurology and director of the Parkinson's Disease and Movement Disorder Center at the University of Kansas Medical Center. He was not involved in the Archives study.

Dr. Pahwa said a serum level scale that enables doctors to determine the prognosis of patients with Parkinson's by measuring their level of urate "would make a big difference."

"Clinically, patients would know what to expect in the future. All we can say now is, 'It's a progressive disease. "