Alzheimer's sleep loss tied to immune cells, not plaques
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Researchers at the University of Kentucky have identified overactive microglia as the primary driver of sleep loss in an Alzheimer's mouse model. Temporarily eliminating most of these immune cells restored more than two hours of sleep per day, even though amyloid plaques remained unchanged. The finding challenges the long-held assumption that sleep disruption stems from damaged neurons or plaques themselves.
The Culprit Identified
A study published in Alzheimer's & Dementia by Shannon L. Macauley, Ph.D., and Nicholas J. Constantino, Ph.D., from the University of Kentucky College of Medicine, shows that microglia—the brain's immune cells—drive sleep loss in Alzheimer's. When microglia respond to amyloid plaques, they trigger widespread inflammation that keeps the brain awake. Temporarily eliminating most microglia with a drug restored more than two hours of sleep per day in mice, despite the persistence of plaques.
Paradigm Shift in Understanding
Previously, scientists attributed Alzheimer's-related sleep loss to neuronal damage or the physical presence of amyloid plaques. The new findings indicate that the disruption stems from a broader immune reaction, described by Macauley as a 'whole house response.' The study compared mice with a genetic tendency for plaques to normal aging mice at six and 18 months, tracking sleep and brain activity.
What's Next
The team plans to investigate whether targeting microglia can improve sleep in human Alzheimer's patients. It remains unclear whether the approach will translate from mice to humans or if long-term microglial suppression carries risks.
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Alzheimer's sleep loss tied to immune cells, not plaques
