Scientists from the University of Rochester Medical Center (USA) have found that only during deep sleep can the brain effectively remove the biochemical "garbage" accumulated during the day, for example, toxic proteins. Disturbances in the mechanism of this "cleaning" lead to the emergence of neurodegenerative diseases, including Alzheimer's disease.
“Sleep is essential for the brain's cleansing system to function well, and this study shows that the deeper we sleep, the better. In addition, these findings underpin the already more compelling evidence to support the hypothesis that the quality of sleep or the degree of sleep deprivation can be judged on the likelihood of Alzheimer's disease and dementia, - said study author Maiken Nedergaard.
Scientists have investigated how depth of sleep affects the functioning of the glymphatic system - the brain's “garbage collection” system, which consists of a network of channels through which cerebrospinal fluid circulates. A group of scientists led by Maiken Nedergaard opened it in 2012. The task of this system is to remove various biochemical "garbage" from the brain.
It is known that the accumulation of toxic proteins such as beta-amyloids and tau in neurons leads to the development of Alzheimer's disease. Based on this, the researchers suggested that the disease may appear due to a disruption in the functioning of the glymphatic system. However, it remained unclear what exactly affects its functioning. Scientists believed that the efficiency of this system was related to the quality of sleep. This hypothesis was consistent with clinical observations: previously, doctors have identified a link between lack of sleep and an increased risk of developing Alzheimer's disease.
In the new study, researchers conducted experiments on mice that were anesthetized with six different drugs. While the animals were anesthetized, the researchers analyzed the electrical activity of their brains, as well as the work of the glymphatic system.
It turned out that intermittent sleep interferes with the normal functioning of the glymphatic system. In addition, some of the types of anesthetics have also negatively impacted the brain cleaning process.
The results of their study also help explain why certain types of anesthesia lead to cognitive impairment in older adults who have undergone surgery, the researchers said. The researchers noted that based on their findings, a new class of harmless anesthetics could be developed, as well as therapies that improve the functioning of the glymphatic system.
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Author: Viktor Mironov
