People with Alzheimer’s disease often struggle with sleep. They may toss and turn at night, take long naps during the day, and become confused or upset in the late afternoon or evening—a symptom known as sundowning.
These daily patterns suggest that the disease may affect the body’s internal clock, or circadian rhythm, which controls sleep, wakefulness, and other daily processes.
Until now, scientists weren’t sure just how deeply Alzheimer’s affected this system. But researchers at Washington University School of Medicine in St. Louis have found strong evidence in mice that Alzheimer’s disrupts the circadian rhythm inside specific brain cells.
This disruption affects hundreds of genes that help the brain work properly. The study was published in the journal Nature Neuroscience.
Led by Dr. Erik S. Musiek, the team discovered that in healthy brains, about half of the 82 genes linked to Alzheimer’s are turned on and off following a regular daily cycle.
But in mice with Alzheimer’s-like disease, these genes lost their rhythm and no longer followed normal timing patterns. This discovery could help researchers find new ways to treat or prevent the disease.
Dr. Musiek explained that understanding how these genes are controlled by the circadian system gives scientists new ideas for therapy. If they can find a way to reset or strengthen these rhythms, it might slow or stop the disease’s progress.
Sleep issues are one of the earliest and most common signs of Alzheimer’s. Many caregivers report poor sleep as one of the most difficult parts of caring for someone with the disease.
These problems not only create stress, but they may also make the disease worse. Earlier research from Dr. Musiek showed that sleep problems can appear years before memory loss begins. That’s why understanding and treating circadian disruption is so important.
One clue came from a protein called YKL-40, which normally rises and falls throughout the day. This protein helps control amyloid in the brain. Amyloid is a sticky substance that builds up and forms plaques in the brains of people with Alzheimer’s. Too much YKL-40, which can happen when the circadian rhythm is off, may cause amyloid to pile up.
To learn more, the team studied mice with amyloid build-up. They collected brain samples every two hours for 24 hours to see how gene activity changed over time. They compared these mice to healthy young mice and older mice without amyloid plaques.
The results showed that in Alzheimer’s mice, hundreds of genes in brain cells called microglia and astrocytes lost their usual rhythm. Microglia help clean up waste in the brain, and astrocytes support brain cell communication.
When their genes became uncoordinated, these brain cells couldn’t function properly. This may explain why the brain struggles to clear away harmful substances like amyloid.
The researchers also found something surprising. Amyloid plaques caused new rhythms to appear in genes that don’t normally follow a daily cycle. These new patterns were linked to inflammation and the brain’s stress response.
Dr. Musiek believes these findings point to a new path for treatment. Instead of just trying to remove amyloid, doctors might one day help restore the brain’s internal clock. By targeting specific brain cells and resetting their timing, it may be possible to improve how the brain handles stress, inflammation, and toxins.
While more work is needed, this study gives hope that fixing the body’s natural rhythms could play a key role in fighting Alzheimer’s disease.
If you care about Alzheimer’s disease, please read studies that bad lifestyle habits can cause Alzheimer’s disease, and strawberries can be good defence against Alzheimer’s.
For more information about brain health, please see recent studies that oral cannabis extract may help reduce Alzheimer’s symptoms, and Vitamin E may help prevent Parkinson’s disease.
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