Insomnia Treatment Linked to Brain Damage Prevention in Alzheimer's Patients
The Global Sleep Disorder Problem
It's shocking to know that roughly 70 million individuals worldwide suffer from sleep disorders, such as insomnia or sleep apnea.
Sleep deprivation night after night can indeed take a toll on your overall health and well-being. These issues can negatively impact a person's concentration and mental health.
Research has shown that sleep disorders can up the risk for various health complications, including heart disease, type 2 diabetes, obesity, gastrointestinal issues, and even dementia and Alzheimer's disease [1].
David M. Holtzman, MD, the Barbara Burton and Reuben M. Morriss III Distinguished Professor of Neurology at Washington University School of Medicine, shared his insights on the link between sleep disruptions and dementia:
"Poor sleep quality and sleep disorders often appear years before other symptoms of dementia due to Alzheimer's disease and related disorders become apparent. Research from our lab and others has shown that disrupted sleep elevates levels of both tau and beta-amyloid, two hallmarks signs of Alzheimer's disease," Holtzman explained [1].
A New Housing for Sleep
Recently, a study published in the journal Science Translational Medicine discovered that a medication commonly used to treat insomnia might not only improve sleep quality but also protect the brain from a buildup of the protein tau [2]. This groundbreaking study involved a mouse model.
The focus for this study was on a sleep disorder medication called lemborexant, sold under the brand name Dayvigo.
"Lemborexant belongs to a class of sleep medications called dual orexin receptor antagonists. These drugs work by blocking orexin – a protein in the brain that keeps us awake and alert," explained Samira Parhizkar, PhD, instructor at Washington University School of Medicine and the first author of this study [2].
"By blocking the orexin signaling, the medication allows sleep to occur quickly and more easily. In other words, if your brain is like a light switch that keeps flicking on when you're trying to sleep, lemborexant helps turn that switch off, so your brain and body get the rest it needs," Parhizkar further explained [2].
Scientists used lemborexant to treat a model of mice that were genetically prone to having tau buildup in the brain.
"In the healthy brain, tau protein acts as a 'track' that helps support the shape of cells and helps move nutrients and signals where they need to go," Holtzman detailed.
"In Alzheimer's and a group of neurodegenerative disorders primarily affected by abnormal tau called tauopathies, abnormal tau loses its shape, integrity, and therefore cellular functionality leading to tau tangles. The progressive build of these tau tangles leads to nerve cell death that contributes to memory loss, confusion, and other cognitive symptoms of Alzheimer's disease," he explained [2].
Lemborexant: A Tau Problem Solver?
At the conclusion of the study, researchers found that treating the mice with lemborexant helped to prevent the buildup of tau in the brain, reducing the inflammatory brain damage that tau buildup is known to cause in Alzheimer's disease [2].
"The detrimental increase of abnormal tau is closely associated with heightened inflammatory damage in the brain," Parhizkar said. "Research from our lab and others has demonstrated that inflammation in the brain is a significant factor contributing to the brain damage seen in neurodegenerative diseases like Alzheimer's."
"Consequently, by decreasing both the abnormal buildup of tau and inflammatory damage, lemborexant may be highly effective in safeguarding the brain from these sources of injury," she added [2].
Additionally, scientists discovered that mice treated with the sleep aid had a 30-40% larger hippocampus volume compared to those not treated with the medication [2].
"The larger hippocampal volume indicates reduced brain damage and cellular loss in mice treated with lemborexant compared to those given vehicle control. In the latter group, abnormal tau protein continued to accumulate in the brain, resulting in cell damage, death, and therefore shrinkage of the hippocampus typically observed with neurodegeneration," Holtzman explained [2].
Additional Insights
Gary Small, MD, Chair of Psychiatry at Hackensack University Medical Center in New Jersey, discussed the study's findings regarding the link between restful sleep and cognitive health. Small, who was not involved in the current study, shared insights from previous research:
"My research team found that sleep quality is related to both objective measures of sustained attention and self-awareness of memory decline, suggesting that interventions for improving sleep quality may contribute not only to improving the ability to focus on a particular task but also in reducing memory complaints," Small said [1].
"Other work has shown that restful sleep reduces brain amyloid and inflammation, which may explain why sleep benefits cognition. The Washington University team now sheds additional light on an underlying link between insomnia and cognitive impairment: accumulation of tau protein, particularly in brain regions controlling memory," Small added [1].
Sleep disorders affect a significant percentage of the population [1]. Finding effective treatments that reduce tau accumulation in the brain and promote restful sleep could have a dual effect of combating Alzheimer's disease and chronic insomnia. However, further research is necessary to fully evaluate the safety and efficacy of this potential treatment in human trials, as warned by Small [1].
- The study published in Science Translational Medicine suggests that a medication used for insomnia, lemborexant, might not only improve sleep quality but also protect the brain from tau buildup, a protein associated with Alzheimer's disease and related neurological disorders.
- The medication lemborexant, sold under the brand name Dayvigo, is from a class of sleep medications called dual orexin receptor antagonists, which work by blocking orexin – a protein in the brain that keeps us awake and alert.
- In Alzheimer's disease and tauopathies, abnormal tau loses its shape and cellular functionality, leading to tau tangles, nerve cell death, memory loss, confusion, and other cognitive symptoms.
- The study found that treating mice with lemborexant helped to prevent the buildup of tau in the brain, reducing the inflammatory brain damage that tau buildup is known to cause in Alzheimer's disease.
- Mice treated with lemborexant had a 30-40% larger hippocampus volume compared to those not treated with the medication, indicating reduced brain damage and cellular loss.
- Improving sleep quality through interventions like lemborexant could potentially contribute to reducing memory complaints, improving the ability to focus, and combating Alzheimer's disease and chronic insomnia, but further research is necessary to fully evaluate its safety and efficacy in human trials.
