Scientists at Washington University School of Medicine in St. Louis have found passageways that connect the brain to vessels that carry fluid waste out of and away from the brain. The newly discovered anatomical structures, found in mice and people, are like tiny gates, allowing waste to leave the brain and enter lymphatic vessels, where immune cells monitor it for signs of danger or infection.
These structures can be likened to airport security checkpoints. Molecules and fluid move in both directions through the gates, but immune cells are tightly regulated. Under normal conditions, immune cells are not allowed past security — similar to sharp objects, firearms and other potential weapons in an airport.
“Any opening can become a weak point when safeguards fail,” explained Jonathan Kipnis, PhD, the Alan A. and Edith L. Wolff Distinguished Professor of Pathology & Immunology and a BJC Investigator. “We have identified a previously unknown route that immune cells can use to access the brain in diseases driven by inflammation. We think these structures, and the cells and molecules strategically positioned around the gates to control passage, can help lead to new drugs for neuroinflammatory diseases.”