New Discovery Revolutionizes Brain Science
For decades, scientists believed they had completely explored the physical structure of the human body. But recently, researchers at the University Virginia School of Medicine have discovered that the brain is directly connected to the immune system by vessels that were previously unknown. This discovery may create dramatic changes in the way we understand and treat diseases like autism, Alzheimer’s and multiple sclerosis.
Jonathan Kipnis, Ph.D., professor in the UVA Department of Neuroscience and director of UVA’s Center for Brain Immunology and Glia (BIG), explains the importance of the discovery:
I really did not believe there are structures in the body that we are not aware of. I thought the body was mapped. I thought that these discoveries ended somewhere around the middle of the last century. But apparently they have not.
Instead of asking, “How do we study the immune response of the brain?” “Why do multiple sclerosis patients have the immune attacks?” now we can approach this mechanistically. Because the brain is like every other tissue connected to the peripheral immune system through meningeal lymphatic vessels. It changes entirely the way we perceive the neuro-immune interaction. We always perceived it before as something esoteric that can’t be studied. But now we can ask mechanistic questions.
We believe that for every neurological disease that has an immune component to it, these vessels may play a major role. Hard to imagine that these vessels would not be involved in a [neurological] disease with an immune component.
Dr. Kevin Lee is chairman of the UVA Department of Neuroscience. The first time the researchers showed him their findings, he exclaimed, “They’ll have to change the textbooks!” Because no one had ever imagined there was a lymphatic system for the central nervous system, the UVA discovery is bound to fundamentally alter the way people envision the relationship between the central nervous system and the immune system.
The researcher who discover the vessels was Antoine Louveau, Ph.D., a postdoctoral fellow in Kipnis’ lab. He developed a method to mount the meninges of a mouse (the membranes that cover the brain) on a single slide, so they could be seen as a whole. He noticed a pattern that looked like vessels distributed within the immune cells on the slides. He ran the test for lymphatic vessels, and there they were.
It was fairly easy, actually. There was one trick: We fixed the meninges within the skullcap, so that the tissue is secured in its physiological condition, and then we dissected it. If we had done it the other way around, it wouldn’t have worked.
I called Jony [Kipnis] to the microscope and I said, ‘I think we have something.
The brain’s lymphatic vessels were very well hidden. They track a major blood vessel down into the sinus area, and are situated so close to the blood vessel it is difficult to see. Living imaging and excellent surgical skills enabled the researchers to see what had never been seen before, and they have since replicated the findings, eradicating any doubt.