Multiple sclerosis: Brain barrier inflammation may play role

Evan Walker
Evan Walker TheMediTary.Com |
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Inflammation in the meninges, the brain’s protective barrier, may contribute to the development of multiple sclerosis. Image credit: Dimitri Otis/Getty Images
  • New research suggests that inflammation in the meninges, the brain’s protective barrier, may extend into the grey matter and contribute to the development of progressive multiple sclerosis (MS).
  • Researchers used innovative techniques to demonstrate a gradient of immune genes and markers of inflammation extending from the meninges to the adjacent brain tissue in mice.
  • While the study sheds light on the mechanisms of brain damage in MS, limitations in spatial resolution and the use of a mouse model demonstrate that further investigations using human samples are needed.

A new study — whose findings appear in eLife as a reviewed preprint — used innovative techniques to demonstrate a gradient of immune genes and markers of inflammation, extending from the meninges to the neighboring brain tissue in mice.

The Health">meninges are a set of three layers of membranes that envelop and safeguard the brain and spinal cord.

These membranes, known as the dura mater, arachnoid mater, and pia mater, serve the purpose of shielding and securing the brain, as well as providing a structural framework for blood vessels, nerves, lymphatics, and the cerebrospinal fluid that envelops the central nervous system.

Inflammation occurring within the meninges is observed in all forms of multiple sclerosis (MS).

Increasing evidence indicates that this inflammation plays a crucial role in the advancement of the disease, including the loss of the protective covering on nerves (demyelination), the loss of newly developed nerve extensions (neurites), and a reduction in the volume of grey matter.

Damage to the grey matter is associated with debilitating symptoms of MS, such as cognitive impairment and depression. Meningeal inflammation seems to be a crucial factor contributing to the pathology of cortical grey matter.

Dr. Pavan Bhargava, an associate professor of neurology in the Division of Neuroimmunology and Neurological Infections at Johns Hopkins University, Baltimore, MD, and senior author of the paper, told Medical News Today that, “while inflammation in the coverings of the brain has been linked to more severe disease and more damage in the brain of people with MS, questions remain about whether the inflammation causes the damage or is simply a response to damage occurring in the brain.”

“We used a technique called spatial transcriptomics that allows us to evaluate [the] expression of genes on a slide providing critical information regarding where different genes are expressed in the brain and surrounding tissue,” Dr. Bhargava explained.

“Using a mouse model of MS we identified areas of inflammation in the coverings of the brain and noted that certain inflammatory gene signatures showed penetration into the adjacent brain tissue while others did not. This suggests that the inflammation in the coverings of the brain is impacting the brain and identifies potential targets for treatment.”

– Dr. Pavan Bhargava

Nancy Mitchell, a registered nurse and contributing writer at Assisted Living Center, not involved in the research, pointed out that “as with most autoimmune diseases, the onset of multiple sclerosis is linked to some level of inflammation in the body — in this case, in the nervous system.”

“This study highlights the relationship between inflammation at the blood-brain barrier and the progression of this disease,” Mitchell explained.

“The parenchyma is the site of the brain associated with cognitive function. It’s highly likely that inflammation — which may be caused by some immune attack or related damage — can cause impaired nervous function and promote MS,” she hypothesized.

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