© 2018 by Janelle E. Letzen, PhD

 
Multiple Sclerosis
What happens to produce multiple sclerosis?
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Myelin is an important part of some neurons for reasons explained here. Demyelination is a loss of myelin around a fairly intact axon. There are multiple causes of demyelination, like inflammation, certain viruses, or lack of oxygen. Multiple sclerosis (MS) is one of the most common “demyelinating diseases”, and white matter demyelination is considered MS’ hallmark pathology.

multiple sclerosis sushi science

MS is a chronic disease of inflammation in the central nervous system (CNS) [3]. While exact triggers for this inflammation are unclear, one of the most popular theories is that MS is an autoimmune disease, meaning the person’s own immune system attacks otherwise healthy myelin [4]. The theory further speculates that attacks leading to myelin damage can result in tissue scarring across multiple areas (sclerosis = scarring). 

 

Myelin is important for rapid communication among neurons. What happens with the breakdown of myelin? Demyelination --> slowed/stopped neuron signaling --> dysfunction across a variety of brain networks --> neurologic symptoms --> disability.
 

Where does demyelination happen, and what symptoms can a person expect? That’s one of the frustrating things about MS…the disease is often unpredictable! Demyelination can happen anywhere in the CNS, meaning the brain and/or spinal cord, resulting in a variety of symptoms ranging from motor difficulty and/or pain to emotional and/or cognitive changes (e.g., difficulty problem-solving, learning new information). On top of that, MS presents differently across people in a pattern of remitting and relapsing disease and/or progressively worsening disease.
 

References

[1] Love, S. (2006). Demyelinating diseases. Journal of clinical pathology, 59(11), 1151-1159.

[2] Trapp, B. D., Vignos, M., Dudman, J., Chang, A., Fisher, E., Staugaitis, S. M., ... & Fox, R. J. (2018). Cortical neuronal densities and cerebral white matter demyelination in multiple sclerosis: a retrospective study. The Lancet Neurology, 17(10), 870-884.

[3] Mahad, D. H., Trapp, B. D., & Lassmann, H. (2015). Pathological mechanisms in progressive multiple sclerosis. The Lancet Neurology, 14(2), 183-193.

[4] Hohlfeld, R., & Wekerle, H. (2004). Autoimmune concepts of multiple sclerosis as a basis for selective immunotherapy: from pipe dreams to (therapeutic) pipelines. Proceedings of the National Academy of Sciences, 101(suppl 2), 14599-14606.

[5] National Multiple Sclerosis Society @multiple.sclerosis_ 

[6] Thompson, A. J., Banwell, B. L., Barkhof, F., Carroll, W. M., Coetzee, T., Comi, G., …& Fujihara, K. (2017). Diagnosis of multiple sclerosis: 2017 revisions of the McDonald criteria. The Lancet Neurology.