Unknown structure in the human skull. It has to do with immunity and Alzheimer’s disease

The skull is full of small tubules that penetrate the cerebrospinal fluid. As a result, the marrow present in the bones of the skull helps fight infections. This discovery has the potential to improve understanding of inflammatory diseases such as dementia and Alzheimer’s disease.

Although it may seem that human anatomy has long been well understood, sometimes scientists discover some new, previously unknown structure in the human body. So it was with with hundreds of tiny channels in the skull discovered some time ago by a team at Massachusetts General Hospital (MGH).

In 2018, researchers from MGH noticed that the cells that respond to infections and brain injuries come from the marrow in the skull and that they pass through these tubules that connect the skull marrow to the area around the meninges. Previously, it was believed that the marrow in various parts of the body reacted to such injuries or infections.

“The brain sends signals to the immune center”

In their latest work, the researchers showed that in addition to passing the immune cells from the marrow to the brain, the tubules allow the cerebrospinal fluid to penetrate into the marrow.

We now know that the brain can send signals to this immune center. In other words, it can call for help in case of trouble such as infection or inflammation. The marrow cells in the skull study the cerebrospinal fluid that passes from the brain through the tubules we discovered earlier “- explains Prof. Matthias Nahrendorf.

“This is probably of great importance for disorders such as dementia or Alzheimer’s disease, because these diseases also depend on inflammation” – emphasizes the expert.

It turns out that not only cerebrospinal fluid and immune cells can penetrate the cranial tubules. Bacteria, e.g. causing meningitis, are also capable of this.

They also reach the marrow in the skull, prompting its cells to respond stronger to the immune response and attack the infection.

Understanding this mechanism may also allow for better treatment of this type of infection.

What are the possibilities of discovering a new area?

Researchers see other benefits as well.

“Our work can also be helpful in investigating situations where the immune response is deleterious, such as when bone marrow-derived immune cells damage the brain and surrounding nerves. Understanding what drives neurinflammation is the first step towards influencing it, ‘says Prof. Nahrendorf.

Author: Marek Matacz

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