Alzheimer’s sleep problems may be reversible, immune cell study in mice suggests

University of Kentucky researchers restore more than two hours of sleep daily by temporarily eliminating overactive microglia, without clearing amyloid plaques

By LineZotpaper

Published20 October 2026

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Scientists have discovered that overactive immune cells in the brain, not amyloid plaques alone, may cause the severe sleep disruptions seen in Alzheimer’s disease. In experiments with mice, temporarily removing most of these cells restored more than two hours of sleep per day, pointing to a potential new treatment approach for one of the condition’s most distressing symptoms.

Researchers at the University of Kentucky have identified an unexpected driver of sleep loss in Alzheimer’s disease: the brain’s own immune cells, called microglia. Rather than simply protecting the brain, these cells can trigger inflammation that interferes with healthy sleep.

The findings, published in the journal Alzheimer’s & Dementia, challenge the long-held assumption that sleep problems stem primarily from damaged neurons or the buildup of amyloid plaques.

“Basically, we showed that it is not the plaques themselves, or solely dysfunctional neurons, that cause sleep loss but actually microglia,” said Shannon L. Macauley, Ph.D., associate professor of physiology at the University of Kentucky College of Medicine and senior author of the study. “Microglia are immune cells that, when they respond to plaques, kick off this elaborate cascade of inflammation, as if the microglia are partying all night, and keeping the brain awake.”

Using mice genetically predisposed to develop amyloid plaques, the team measured sleep via electroencephalography (EEG) and electromyography (EMG). They examined the animals at six months, when plaques first appeared, and at 18 months, when pathology was more advanced. To visualise the relationship between plaques and microglia, they used light-sheet microscopy.

In a key experiment, the researchers administered the drug Pexidartinib (PLX3397) for 14 days, eliminating approximately 87% of the microglia. The result: the mice gained more than two hours of additional sleep per day and spent more time in deep, restorative stages.

Lead author Nicholas J. Constantino, Ph.D., a recent doctoral graduate, noted a surprising pattern: sleep disruption did not worsen as plaque burden more than doubled. “The disruptions in sleep and cortical EEG activity that occur at 6 months, when plaques first emerge, did not worsen by 18 months, despite more than double the amount of plaque burden,” he said. The team described this as a ceiling effect, suggesting the initial inflammatory response is particularly critical.

Macauley called the discovery “paradigm-shifting,” as it opens a new avenue for treating Alzheimer’s-related sleep problems without necessarily targeting plaques themselves.

Analysis

Why This Matters

Sleep disruption is one of the most common and distressing symptoms of Alzheimer’s, affecting patients and caregivers.
The study suggests a new therapeutic target — microglia — rather than amyloid plaques, which have been the focus of most drug development.
If confirmed in humans, this approach could lead to treatments that improve quality of life even without clearing plaques.

Background

Alzheimer’s disease is characterised by the accumulation of amyloid plaques between nerve cells. Sleep disturbances often appear early and worsen over time. Microglia are the brain’s resident immune cells; they normally clear debris and respond to injury, but in Alzheimer’s they can become chronically activated, releasing inflammatory signals. The link between neuroinflammation and sleep has been suspected but not directly demonstrated until now.

Key Perspectives

University of Kentucky researchers: The team argues that microglial activation, not plaque buildup alone, drives sleep loss. Eliminating microglia restored sleep in mice, offering a proof of concept for a new treatment strategy. Potential human applicability: While promising, the study was conducted in mice. Human microglia are similar but not identical, and Pexidartinib has significant side effects. Researchers will need to develop safer methods to modulate microglial activity. Critics/Skeptics: Some neuroscientists may caution that depleting microglia entirely is not a viable long-term strategy, as these cells perform essential protective functions. The ceiling effect observed also raises questions about timing — early intervention may be critical.

What to Watch

Whether pharmaceutical companies begin developing microglia-modulating drugs for Alzheimer’s-related sleep disorders.
Follow-up studies in other animal models and, eventually, early-phase human trials.
Research into whether similar immune-driven sleep disruption occurs in other neurodegenerative diseases.

Sources

"Mind-blowing" Alzheimer’s breakthrough: Two hours of sleep restored without clearing brain plaques · Latest Science News -- ScienceDaily

Checked

12 claims in this story checked against 1 source: 12 supported.

Show each claim

SupportedAlzheimer’s sleep problems may be reversible, immune cell study in mice suggestsLatest Science News -- ScienceDaily: “Scientists have discovered an unexpected reason why Alzheimer's disease disrupts sleep, and their findings suggest that the problem may be reversible.”
SupportedUniversity of Kentucky researchers restore more than two hours of sleep daily by temporarily eliminating overactive microglia, without clearing amyloid plaquesLatest Science News -- ScienceDaily: “removing them restored more than two hours of sleep per day in mice... without removing the amyloid plaques”
SupportedScientists have discovered that overactive immune cells in the brain, not amyloid plaques alone, may cause the severe sleep disruptions seen in Alzheimer’s disease.Latest Science News -- ScienceDaily: “Basically, we showed that it is not the plaques themselves, or solely dysfunctional neurons, that cause sleep loss but actually microglia,”
SupportedIn experiments with mice, temporarily removing most of these cells restored more than two hours of sleep per day, pointing to a potential new treatment approach for one of the condition’s most distressing symptoms.Latest Science News -- ScienceDaily: “The animals gained more than two hours of sleep per day.”
SupportedResearchers at the University of Kentucky have identified an unexpected driver of sleep loss in Alzheimer’s disease: the brain’s own immune cells, called microglia.Latest Science News -- ScienceDaily: “Researchers at the University of Kentucky found that temporarily eliminating most of these immune cells allowed the mice to sleep longer”
Supported“Basically, we showed that it is not the plaques themselves, or solely dysfunctional neurons, that cause sleep loss but actually microglia,” said Shannon L. Macauley, Ph.D., associate professor of physiology at the University of Kentucky College of Medicine and senior author of the study.Latest Science News -- ScienceDaily: “Basically, we showed that it is not the plaques themselves, or solely dysfunctional neurons, that cause sleep loss but actually microglia,”
Supported“Microglia are immune cells that, when they respond to plaques, kick off this elaborate cascade of inflammation, as if the microglia are partying all night, and keeping the brain awake.”Latest Science News -- ScienceDaily: “Microglia are immune cells that, when they respond to plaques, kick off this elaborate cascade of inflammation, as if the microglia are partying all night, and keeping the brain awake.”
SupportedThe findings, published in the journal *Alzheimer’s & Dementia*, challenge the long-held assumption that sleep problems stem primarily from damaged neurons or the buildup of amyloid plaques.Latest Science News -- ScienceDaily: “The findings, published in the journal Alzheimer's & Dementia... challenges the prevailing understanding of why people with Alzheimer's often experience severe sleep problems.”
SupportedIn a key experiment, the researchers administered the drug Pexidartinib (PLX3397) for 14 days, eliminating approximately 87% of the microglia.Latest Science News -- ScienceDaily: “The researchers administered a drug called Pexidartinib (PLX3397)... after the mice received the medication in their food for 14 days, approximately 87% of their microglia had been depleted.”
SupportedThe result: the mice gained more than two hours of additional sleep per day and spent more time in deep, restorative stages.Latest Science News -- ScienceDaily: “The animals gained more than two hours of sleep per day. They also experienced longer periods of restorative NREM sleep.”
SupportedLead author Nicholas J. Constantino, Ph.D., a recent doctoral graduate, noted a surprising pattern: sleep disruption did not worsen as plaque burden more than doubled.Latest Science News -- ScienceDaily: “Constantino said: 'The disruptions in sleep and cortical EEG activity that occur at 6 months, when plaques first emerge, did not worsen by 18 months, despite more than double the amount of plaque burden.'”
SupportedMacauley called the discovery “paradigm-shifting,” as it opens a new avenue for treating Alzheimer’s-related sleep problems without necessarily targeting plaques themselves.Latest Science News -- ScienceDaily: “Macauley described the discovery as 'paradigm-shifting' because it challenges the prevailing understanding”