The overlap of green (glial cells) and purple (water channels embedded in the walls of those cells) show the tubes.
Your blood vessels aren’t the only network of tubes winding through your body. The lymph vessels, or lymphatics, shadow blood vessels wherever they go and collect waste from around the body, as well as shuttling around immune cells and performing other functions. But the lymphatics never make it to the brain, scientists were surprised to find some years ago. Some other, mysterious method for removing waste from the brain must exist.
In a new paper in Science Translational Medicine, a team of neuroscientists reports that they’ve discovered a system of tubes that encircle the blood vessels that feed the brain. The walls of these tubes are made up of spindly projections from brain cells called glia, that, in the same way that trees’ arching limbs form a tunnel over a road, arch around the blood vessels to form the tubes. And these tubes seem to drain the way lymphatics do, suggesting that they might be long-sought gutter of the brain.