New Vessels Discovered In The Brain

Research has uncovered previously unknown lymphatic vessels in the brain, with possible implications for neurodegenerative disease

We like to think we know a great deal about biology, but every now and then we're reminded of how much we've yet to understand. The discovery of new meningeal vessels that link the immune system to the brain was actually published last year in Nature, but when the same team demonstrated recently that the immune system could be influencing behaviour in response to pathogen exposure through such vessels, the finding is back in the headlines. 

"I really did not believe there were structures in the body that we were not aware of, I thought the body was mapped" 

New information on the immune system

To uncover the vessels, researchers analysed a sample of the meningeal section of a mouse brain, and found that there were immune cells spread in a vein-like pattern - indicating the presence of specialised vessels. When they injected dye laden fluid into the brain, they could even trace its passage through these mysterious pathways. Curiously, although not surprisingly, in autopsies similar vessels have now been noted in humans. 

Credit: University of Virginia

What can we take from this?

In the latest research by the same team, it was discovered that a single molecule released by the immune system can affect a mouse's social behaviour. Perhaps more importantly however, with the recent suggestion Alzheimer's has an immune component - in that beta amyloid is actually anti-microbial and may protect against infection - this raises many new questions about the immune system's role in keeping the brain healthy. We can expect a great deal more research to be conducted in this area, in an effort to understand what role these vessels play in removing undesirable products or invaders from the brain. 

"In Alzheimer’s, there are accumulations of big protein chunks in the brain, We think they may be accumulating in the brain because they're not being efficiently removed by these vessels. There has never been a lymphatic system for the central nervous system, and it was very clear from that first singular observation - and they’ve done many studies since then to bolster the finding - that it will fundamentally change the way people look at the central nervous system’s relationship with the immune system"

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