From Scientific American:
The brain can be a messy place. Thankfully, it has good plumbing: Scientists have just discovered a cleansing river inside the brain, a fluid stream that might be enlisted to flush away the buildup of proteins associated with Alzheimer's, Huntington's and other neurodegenerative disorders. The researchers, based at the University of Rochester (U.R.), University of Oslo and Stony Brook University, describe this new system in the journal Science Translational Medicine today. The study adds to the evidence that the star-shaped cells called astrocytes play a leading role in keeping the nervous system in good working order.
In most of the body, a network of vessels carry lymph, a fluid that removes excess plasma, dead blood cells, debris and other waste. But the brain is different. Instead of lymph, the brain is bathed in cerebrospinal fluid. For decades, however, neuroscientists have assumed that this fluid simply carries soluble waste by slowly diffusing through tissues, then shipping its cargo out of the nervous system and eventually into the body's bloodstream. Determining what's really going on has been impossible until recently. In this study, researchers led by U.R. neuroscientist Maiken Nedergaard have identified a second, faster brain-cleansing system.