A startling discovery by researchers from the University of Virginia has turned decades of textbook knowledge on its head. The brain has been thought to have non-existent ducts directly connected to the immune system. The lymphatic system throughout the body has been able to be mapped out completely, however, these ducts have still been missed, but now that the ducts have been discovered in a significant way, it could have implications for the research and treatment of neurological disorders including autism, Alzheimer’s and multiple sclerosis, among others. ‘Why are people with multiple sclerosis under immune attack?’ , because the brain is actually connected to the peripheral immune system through meningeal lymphatics just like any other tissue,” said Jonathan Kipnis, Ph.D., director of the Brain Immunity and Glioblasts (BIG) Center at the University of Virginia and a professor in the Department of Neuroscience at the University of Virginia. “This discovery revolutionizes our understanding of neuro-immune interactions. We often thought before that this interaction was profoundly difficult to study. But now we can ask mechanistic questions.” “We believe that the immune system is involved in every neurological disease, and that these lymphatics all play a major role,” Kipnis says. “It’s hard to imagine a neurological disease in which the immune system is involved that has nothing to do with these lymphatics.” New Discoveries in the Human Body Dr. Kevin Lee, chair of the Department of Neuroscience at the University of Virginia, recounted his reaction to the findings of Kipnis’s lab: the first findings that will change the textbooks.’ It had never been found before that there was a lymphatic system in the central nervous system, and this new discovery made that very clear, and after that, they did a lot of research to validate the discovery. It will revolutionize the way people look at the relationship between the CNS and the immune system.” Kipnis was even skeptical at first. “I really kind of couldn’t believe that there were structures in the human body that we didn’t realize were there. I thought the human body had been completely mapped, and I thought these human discoveries had ended by the middle of the last century. But now it looks like it’s not over.” Well-hidden Antoine Louveau, a post-doctoral fellow in the Kipnis lab, made this discovery possible.Louveau invented a new method of crawling slices of a mouse’s meninges, the membrane that covers the brain, on a slide.A little trick is that, by holding the meninges in place in the skull, the tissue is intact in its physiological condition, and then. we then dissect it. If we dissected before fixing, the experiment would not work.” When he noticed lymphocytes distributed in a pattern of lymphatic vessels on the slide, he detected and confirmed them. What was once thought to be unlikely turned out to be there.Louveau recalls the moment, “I called Kipnis into the microscope room and said, ‘I think we’ve found something.'” Because the brain’s lymphatic vessels have been so long undetected, Kipnis describes them as “very good at hiding,” and they follow the major blood vessels into the sinuses, an area that can be difficult to observe. “They are very close to the blood vessels, so it’s easy for people to miss them. “Real-time imaging of these lymphatic vessels is important to discover their function, and we couldn’t have done it without working with Tajie Harris,” Kipnis emphasized.Harris is a BIG Center member and assistant professor in the Department of Neuroscience.Kipnis also thanked Igor Kipnis also thanked the “amazing” surgical skills of Igor Smirnov, a research assistant in Kipnis’ lab, who was critical to the success of the imaging study. Alzheimer’s, autism, multiple sclerosis and others The presence of these unexpected lymphatic vessels raises a host of questions that need to be answered about the brain’s function and the diseases that surround it. In Alzheimer’s disease, for example, “In Alzheimer’s, there’s a huge amount of proteins deposited in the brain,” Kipnis says, “and we think that these proteins are deposited because they can’t be cleared out efficiently by these lymphatic vessels.” He emphasizes that these lymphatic vessels look different with age, so the role of these ducts in aging is another area of research. In addition, a great deal of research into neurological disorders, from autism to multiple sclerosis, should now reconsider what the original science has insisted doesn’t exist, but actually does.”