Sleep & RecoveryYour Blood Cells Clean the Brain During Sleep — And Without Them, Memory Fails
Scientists at the University of Pennsylvania have discovered that circulating immune cells called haemocytes — the fly equivalent of macrophages — travel to the brain specifically during sleep and remove lipid buildup that accumulates from daytime oxidative stress. Using the fruit fly Drosophila as a model, researchers showed that haemocyte numbers in the head cavity peak during sleep periods and drop with sleep deprivation. A receptor called Eater mediates this lipid clearance. When Eater is knocked out, lipids accumulate, brain acetylation rises, mitochondria dysfunction, NAD+ levels fall, and flies suffer memory impairment and shortened lifespan. The findings suggest a critical peripheral immune function for sleep that may translate to mammalian microglia biology.
