For the first time, the complete pathological progress of multiple sclerosis has been documented, exposing the inflammatory and neurodegenerative processes at work.
In multiple sclerosis (MS), the insulating layers of nerve fibers are destroyed by chronic inflammation in the nervous system. However, the mechanisms behind the advanced stages of the disease are not fully understood, and existing treatments have a very limited effect on patients with advanced MS.
Whether MS is caused by an as-yet unidentified infectious pathogen or an autoimmune response has not yet been established. Around 2.5 million people are affected by the condition worldwide.
Prior to this new study, researchers had adopted two approaches to categorizing MS. One of these approaches was to think of MS as a disease of the nervous system that causes inflammation responsible for the neurodegenerative damage. The other approach was to think of MS as a disease that progresses from being an inflammatory condition into a neurodegenerative one.
The new study – conducted by researchers from the Medical University of Vienna in Austria and published in The Lancet Neurology – suggests that the inflammatory process drives the disease from onset to the later stages, with the neurodegenerative process occurring in the progressive phase of MS.
In this later phase of the condition, the researchers elaborate, “amplification mechanisms” are triggered. These mechanisms provoke a destructive cycle that causes increasing damage.
For example, the damage to the brain activates microglial cells, which along with the formation of lipid-destroying oxygen radicals, drive the disease forward. Consequent damage to the mitochondria – the “power plants” of brain cells – then causes further damage.
Study leader Hans Lassmann, head of the Department of Neuroimmunology at the Medical University of Vienna, explains the findings:
“The inflammatory process, which can be treated effectively in the early stages, becomes less pronounced with age. However, the neurodegenerative damage increases. This also explains why drugs that initially work well later lose their effectiveness.”
Lassmann believes that the documentation of these mechanisms will lead to new MS treatments.
“First,” he begins, “drugs could be developed that have an anti-inflammatory effect in the brain too, not just suppressing the defense response in the blood and lymphatic organs. Secondly, neuroprotective treatments could be developed that preventively block the amplification mechanisms and damage to the mitochondria, thereby preventing consequential damage.”
Studies involving potential new drugs based on the data gathered from this study are already underway. However, the results will not be public for at least another 5 years.
“I firmly believe that in the foreseeable future, so within the next 5 to 10 years, we will be successful in fighting the amplification mechanisms and slowing down the progressive phase further,” Lassmann asserts.
As well as suggesting new treatments for MS, the findings provide further understanding of the brain’s natural aging process and also have implications for other neurodegenerative conditions, such as Alzheimer’s disease and Parkinson’s disease.
Recently, Medical News Today looked at a study published in the Journal of Neurology, Neurosurgery & Psychiatry that investigated the potential of a common gut bacteria to reduce risk of MS in women. And in 2014, another study in that journal found a link between salt consumption and heightened MS symptoms.