People who experience chronic sleep disturbance may face an earlier onset of dementia and Alzheimer's, according to a recent study.
Researchers from Temple University found that chronic sleep disturbance - either through their work, insomnia or other reasons - could trigger onset of Alzheimer's. They were trying to figure out whether sleep disturbance is a risk factor to develop Alzheimer's or if it is something that manifests with the disease, according to a press release.
"We can conclude from this study that chronic sleep disturbance is an environmental risk factor for Alzheimer's disease," Domenico Praticò, professor of pharmacology and microbiology/immunology in Temple's School of Medicine, said in a statement. "But the good news is that sleep disturbances can be easily treated, which would hopefully reduce the Alzheimer's risk."
For the study, researchers used a transgenic Alzheimer's mouse model that begins developing memory and learning impairment at about one year - the equivalent of a human that is mid-50 to 60 years in age- and at 14 to 15 months have the typical human brain pathology of Alzheimer's, including amyloid plaques and tau protein tangles, the two major brain pathological/lesion signatures for the disease. The study, which spanned eight weeks, began when the mice were approximately six months old, or the equivalent of an adult human in their 40s. One group of mice was kept on a schedule of 12 hours of light and 12 hours of darkness, while a second group was subjected to 20 hours of light and only four hours of darkness, greatly reducing their amount of sleep.
"At the end of the eight weeks, we didn't initially observe anything that was obviously different between the two groups," said Praticὸ, who is also a member of Temple's Center for Translational Medicine. "However, when we tested the mice for memory, the group which had the reduced sleep demonstrated significant impairment in their working and retention memory, as well as their learning ability."
They observed that sleep deprived mice developed Alzheimer's brain pathology earlier than mice that were not deprive.
Researchers concluded that sleep disturbance acts as a trigger that accelerates the pathological process of tau becoming phosphorylated and irreversibly damaging the synaptic connection.
"We can conclude from this study that chronic sleep disturbance is an environmental risk factor for Alzheimer's disease," Praticὸ said. "But the good news is that sleep disturbances can be easily treated, which would hopefully reduce the Alzheimer's risk."
The findings were published in the recent issue of Neurobiology of Aging.
