Uric acid appears to be a wonder drug in mice: It wards off a disease that resembles multiple sclerosis (MS), an autoimmune disorder in people, and allows partially paralyzed mice to walk again. New findings, reported in today's issue of the Proceedings of the National Academy of Sciences, suggest that uric acid might soon see duty in people, too. Researchers have confirmed that MS patients are deficient in uric acid, a compound derived from a range of dietary sources, from coffee to chopped liver.
Studies have implicated high levels of a corrosive chemical, peroxynitrite, as a prime suspect in the scarring of the brain and spinal cord that causes MS. Scientists from Thomas Jefferson University in Philadelphia decided to see whether sopping up this toxic chemical might help prevent the mouse version of MS, called experimental allergic encephalomyelitis (EAE). They found that a steady supply of uric acid scavenged the peroxynitrite in the blood stream and prevented the disease.
Now, immunologist D. Craig Hooper and his colleagues at Thomas Jefferson have gone a step further, testing uric acid in mice with EAE, a fatal condition. They gave the mice EAE and allowed the disease to develop for 12 days. They then injected half the mice with uric acid two times a day for 7 days. Those mice outlasted their treatment regimen, while untreated controls at the same disease stage died within 4 days. In addition, mice with paralyzed tails and rear legs regained some function. However, Hooper cautions, "mice that have irreversible damage aren't going to get up and start walking around."
The researchers also found that uric acid levels were about 15% lower in people with MS than in healthy subjects. Anne Cross, a neurologist at Washington University School of Medicine in St. Louis, says of peroxynitrite, "we don't really know its exact role. ... It might have both positive and negative effects." The Thomas Jefferson group next plans to test uric acid in a clinical trial. Hilary Koprowski, a professor of immunology and microbiology with the Thomas Jefferson group, says, "We hope that uric acid will arrest disease progression."