0826 GMT July 20, 2019
People deprived of sleep for one night experience an immediate and significant increase in beta amyloid, a substance that clumps together between neurons to form plaques that hamper the brain's ability to function, UPI reported.
Study author Ehsan Shokri-Kojori, a research fellow with the US National Institute on Alcohol Abuse and Alcoholism, said, "We certainly show that even one night of sleep deprivation can increase the levels of these harmful beta amyloid compounds.
"That's a very logical assumption, I would say, and it's consistent with prior research.”
Previous mouse and human studies have found potential links between too little sleep and an accumulation of beta amyloid in the brain, researchers said.
However, many of the human studies have relied on self-reports of sleep quality.
So Shokri-Kojori and his team decided to create an experiment that would more precisely test the effect of sleep deprivation on beta amyloid levels in humans.
They recruited 20 healthy people with no history of brain disorders, and had them spend two nights in the lab — one in which they were allowed to get a good night's rest, and another in which they didn't sleep a wink.
The morning after both nights, the participants underwent brain scans to assess their levels of beta amyloid.
The researchers found that sleep deprivation was associated with a significant increase in beta amyloid in the brain, when compared with a good night's sleep.
Shokri-Kojori said, “Further, the beta amyloid increases were observed in regions of the brain important to memory and thought.”
These included the hippocampus, which has been tied to memory, and the thalamus, which is an important hub for relaying sensory information to the brain.
Dr. Andrew Varga, an assistant professor of sleep medicine with Mount Sinai Health System in New York City, said, “Experts suspect that every time a neuron fires, it contributes to the production of beta amyloid in the brain.
“When people don't sleep, their neurons continue to fire, potentially leading to a buildup of beta amyloid.”
Varga and Shokri-Kojori said, “It also is possible that sleep aids the removal of waste products from the brain, which include beta amyloid.”
The experts said, “During sleep, neurons shrink in size, creating space between the cells that allows waste products to be more readily cleared from the brain.
“However, more study needs to be done to directly link lack of sleep with risk of Alzheimer's disease.”
Shokri-Kojori said added, “For example, it's not known whether a good night's sleep can wipe out the accumulation of beta amyloid from a short bout of insomnia.
“One future experiment might entail participants undergoing a night of sleep deprivation followed by a night of sound sleep, with brain scans detailing whether good sleep can restore brain health.”
Varga said, “Researchers also need to show that continued high levels of beta amyloid in the brain actually increase the chances of clumps forming between neurons.
"It makes intuitive sense that if you have chronically high levels of beta amyloid they would congregate together and form plaques, but that piece of it is not fully fleshed out.”