Understanding the damage that occurs to the brain and spinal cord during multiple sclerosis is key to finding ways to stopping MS progression. A new study by researchers in Austria provides new clues to the type and extent of nervous system damage in MS, opening new paths for further exploration that could eventually lead to better treatments to stop MS in its tracks. Lukas Haider, MD, Josa Frischer, MD and colleagues (Medical University of Vienna) report their findings in the Journal of Neurology, Neurosurgery and Psychiatry (Published Online June 4, 2014). The study was supported by the Austrian Science Fund.
Background: MS involves immune system attacks to the brain and spinal cord. The “white matter” in the brain consists of nerve fibers, which transmit messages to, from, and throughout the brain, and myelin. Myelin, the fatty substance that surrounds and protects nerve fibers, is white in color and is a major target of the immune system in MS. The “gray matter” in the brain includes the nerve cells and several associated structures. Recent research suggests that the gray matter is also damaged by MS, may be damaged early in the disease process, and has been linked to cognitive symptoms and disease progression.
The Study: Dr. Haider’s team studied the distribution of lesions – areas of damage – in brain tissue obtained from 75 people with MS via autopsy, as well as 12 controls without MS. Using a series of sophisticated laboratory techniques, they found that damage to gray matter was most prominent in the area of the brain known as the “basal ganglia,” an area associated with motor abilities, learning, cognition, and emotion.
Both white and gray matter damage were found in people with all types of MS. The extent of gray matter damage was similar in people with all types of MS, but white matter damage was more extensive in people with progressive MS. These findings indicate that there are important differences in the mechanisms by which white and gray matter damage develops, and these differences are apparent as well when damage develops in different parts of the brain.
The team also found elevated levels of iron in gray matter lesions, which appears to be liberated from myelin-making cells during injury and which may mean that these levels play a role in nerve cell degeneration in MS. Iron has been implicated in amplifying oxidative injury (a process wherein “free radicals,” normal byproducts of bodily processes, cause tissue injury).
Conclusion: This study provides some new information on nervous system damage caused by MS. More research, which is currently underway by investigators worldwide, is needed to understand the timing of the damage and to determine how this knowledge can be translated to new approaches to stopping MS progression.