Sodium buildup in brain linked to disability in MS patients

Sodium buildup in the brain seems to be linked to disability in people with multiple sclerosis, researchers have found. This accumulation of sodium could be an indicator of the degeneration of nerve cells that results from the disease, according to a team of European researchers. Although multiple sclerosis, or MS, symptoms vary from patient to patient, the study authors suggested that their findings may help predict the severity of disease progression and disability. "A major challenge with multiple sclerosis is providing patients with a prognosis of disease progression. It's very hard to predict the course of the disease," Patrick Cozzone, director emeritus of the Center for Magnetic Resonance in Biology and Medicine, a joint unit of National Center for Scientific Research and Aix-Marseille University in Marseille, France, said in a news release from the Radiological Society of North America. In conducting the study, the researchers used a specific type of imaging technology that provides information on the sodium content of cells in the body, known as 3 Tesla sodium MRI. The test was performed on 26 patients with relapsing-remitting MS, the most common form of the disease, in which flare-ups of symptoms are followed by periods of recovery. Of the study's participants, 14 had early stage relapsing-remitting MS and 12 had advanced forms of the disease. The researchers also examined 15 healthy participants without MS that they matched for the patients' ages and genders. "We collaborated for two years with chemists and physicists to develop techniques to perform [3 Tesla] sodium MRI on patients," Wafaa Zaaraoui, research officer at the National Center for Scientific Research, said in the news release. "To better understand this disease, we need to probe new molecules. The time has come for probing brain sodium concentrations." The MRI results for patients with early stage relapsing-remitting MS revealed abnormally high levels of sodium in certain areas of the brain, including the brainstem, cerebellum and temporal pole. High sodium accumulation was found throughout the entire brains of patients with advanced forms of the disease -- even in brain tissue that appeared to be normal, the researchers found. When sodium collected in areas of the brain responsible for motor skills, there was a direct connection to the level of disability seen in people with advanced-stage MS, the researchers noted. "In [relapsing-remitting MS] patients, the amount of sodium accumulation in gray matter associated with the motor system was directly correlated to the degree of patient disability," said Zaaraoui. The study authors suggested that their findings might help drug companies in developing new MS treatments. "Brain sodium MRI can help us better understand the disease and monitor the occurrence of neuronal injury in MS patients and possibly in patients with other brain disorders," Jean-Philippe Ranjeva, professor of neuroscience at Aix-Marseille University, concluded in the news release. The study was published in the July 17 online edition of the journal Radiology. Although the study uncovered an association between sodium buildup in the brain and MS disability, it did not prove a cause-and-effect relationship.