Gladstone scientists track exact routes used to clear brain waste

Think of the brain as if it were a house. Insulated from its environment, a house relies on complex networks-pipes, drains, and disposal systems-that interface with the outside world to keep the home functional on the inside. But when this infrastructure breaks down, trash accumulates and the resulting damage can be difficult to reverse.

Similarly, the brain is largely isolated from the rest of the body, sealed off by barriers that carefully control what gets in and out. And as one of the body's most active organs, it constantly produces waste as a byproduct of its work. As a result, the brain has developed dedicated networks for waste disposal and drainage. When those networks fail, toxic proteins can build up and trigger devastating diseases like Alzheimer's.

Traditionally, to investigate these networks, scientists injected tracers into the cerebrospinal fluid, which acts as a vehicle for removing brain waste. But akin to flooding a house, this method revealed all possible points of leakage without indicating which exits are normally used.

This left a fundamental question unanswered: how do the waste proteins made inside the brain find their way out?