Sodium Buildup in Brain Associated to Disability in Multiple Sclerosis

A study that is being published in the Journal Radiology claims that, "A buildup of sodium in the brain detected by magnetic resonance imaging (MRI) may be a biomarker for the degeneration of nerve cells that occurs in patients with multiple sclerosis."

According to the team of European researchers who conducted the study, patients with early-stage MS showed sodium accumulation in specific brain regions, while patients with more advanced disease showed sodium accumulation throughout the whole brain.

The presence of sodium buildup in the motor areas of the brain existed then it is correlated directly to the degree of disability that is observed in the advanced stage patients.

"A major challenge with multiple sclerosis is providing patients with a prognosis of disease progression," said Patrick Cozzone, Ph.D., director emeritus of the Center for Magnetic Resonance in Biology and Medicine, a joint unit of National Center for Scientific Research (CNRS) and Aix-Marseille University in Marseille, France. "It's very hard to predict the course of the disease."

The people who are a victim of multiple sclerosis, their body immune system attacks the protective myelin sheath that wraps around the controlling units like the nerve cells or neurons present in the brain and spinal cord. The scarring affects the neurons' ability to conduct signals, causing neurological and physical disability. The type and severity of MS symptoms, as well as the progression of the disease, vary from one patient to another.

For the study, Dr. Cozzone, along with Wafaa Zaaraoui, Ph.D., research officer at CNRS, Jean-Philippe Ranjeva, Ph.D., professor in neuroscience at Aix-Marseille University and a European team of interdisciplinary researchers used 3 Tesla (3T) sodium MRI to study relapsing-remitting multiple sclerosis (RRMS). They noticed that the most common type of disease which clearly projects attacks of worsening neurological function are followed by periods of recovery.

The amount of sodium content of cells in the body is detected with the help of images produced by Sodium MRI.

"We collaborated for two years with chemists and physicists to develop techniques to perform 3T sodium MRI on patients," Dr. Zaaraoui said. "To better understand this disease, we need to probe new molecules. The time has come for probing brain sodium concentrations."

The sodium MRI was conducted on 26MS patients using specially designed hardware and software. Out of the 26 MS patients, 14 were with early stage RRMS i.e less than 5 years in duration. And 12 that showed advanced diseases i.e more than 5 years and the remaining 15 age and sex matched control participants.

The researchers observed that in the early-stage RRMS patients, sodium MRI revealed abnormally high concentrations of sodium in specific brain regions, including the brainstem, cerebellum and temporal pole. In the advanced-stage RRMS patients, abnormally high sodium accumulation was widespread throughout the whole brain, including normal appearing brain tissue.

"In RRMS patients, the amount of sodium accumulation in gray matter associated with the motor system was directly correlated to the degree of patient disability," Dr. Zaaraoui said.

Current medication that is available for MS are only able to slow the progress of the disease. The use of sodium accumulation as a biomarker of neuron degeneration may assist pharmaceutical companies in developing and assessing potential treatments.

Dr. Ranjeva concluded saying, "Brain sodium MR imaging can help us to better understand the disease and to monitor the occurrence of neuronal injury in MS patients and possibly in patients with other brain disorders,"