Alzheimer's Breakthrough: Scientists Restore Two Hours of Sleep by Targeting Overactive Brain Immune Cells
Researchers at the University of Kentucky found that overactive microglia, the brain's immune cells, are a primary driver of sleep loss in Alzheimer's disease. By temporarily depleting these cells in mouse models, the team restored more than two hours of sleep per night without reducing amyloid plaque levels. The discovery points to a potentially reversible therapeutic target for treating sleep disruption in Alzheimer's patients.
Researchers at the University of Kentucky published findings in the journal Alzheimer's and Dementia showing that overactive microglia, the brain's resident immune cells, are a primary driver of sleep loss in Alzheimer's disease. By temporarily depleting these immune cells in mouse models, the team restored more than two hours of sleep per night without reducing amyloid plaque burden.
The research was led by Dr. Shannon L. Macauley and Dr. Nicholas J. Constantino. Traditional theories about Alzheimer's-related sleep loss often pointed to the direct toxicity of amyloid plaques or the physical degradation of neurons. This study found that microglia play a central role instead.
In response to the presence of amyloid plaques, microglia initiate an inflammatory cascade that keeps the brain in a state of heightened activity, preventing deep, restorative non-rapid eye movement sleep. The researchers described this as a whole house response, where an immune system intended to protect the brain ends up causing systemic disruption.
The study used two groups of mice, those genetically predisposed to amyloid plaques and wild-type mice, at both six months and 18 months of age. Using electroencephalography and electromyography to monitor sleep patterns, researchers found that amyloid pathology specifically targeted restorative NREM sleep.
To confirm the role of microglia, the team administered the cancer drug Pexidartinib for 14 days, which temporarily eliminated approximately 87 percent of the brain's immune cells. Mice regained more than two hours of sleep per night, and this improvement occurred despite the amount of amyloid plaque remaining unchanged.
The laboratory is now researching whether existing medications, specifically the diabetes drug Metformin and the antiseizure drug Stiripentol, can reprogram how microglia use energy, reducing their overactivity without the need to deplete them entirely.
Researchers also identified electrical signatures of Alzheimer's that could potentially be detected via portable, non-invasive EEG systems, offering a possible affordable biomarker for early disease screening.
