Just one night of lost sleep can fill the brain with the protein that has long been linked to the development of Alzheimer’s disease, the protein beta-amyloid e, a new study published in the journal has revealed. Proceedings of the National Academy of Sciences (PNAS).
The work has found that people who are deprived of sleep for a single night experience an immediate and significant increase in beta amyloid, the substance that clusters between neurons to form plaques that impede the brain’s ability to function.
“Certainly, we show that even one night of sleep deprivation can increase the levels of these harmful beta amyloid compounds. That is a very logical assumption and is consistent with previous research ,” said Ehsan Shokri-Kojori, leader of the work.
Previous studies in humans and mice have found possible links between lack of sleep and an accumulation of beta amyloid in the brain. However, many of the studies in humans have been based on self-reports of sleep quality.
Hence, this team of experts decided to conduct an experiment that would more accurately test the effect of sleep deprivation on amyloid beta levels in humans . With the participation of 20 healthy people with no history of brain disorders, they were asked to spend two nights in the laboratory; one in which they were allowed to get a good night’s rest and the other in which they could not sleep at all.
The morning after each night, the participants underwent brain scans to assess their amyloid beta levels.
The researchers found that sleep deprivation was associated with a significant increase in amyloid beta in the brain (in 19 of the 20 subjects), compared to a good night’s sleep. Additionally, amyloid beta increases were seen in brain regions important for memory and thinking, such as the hippocampus (related to memory) and the thalamus (an important center for transmitting sensory information to the brain).
Experts suspect that every time a neuron fires, it contributes to the production of beta amyloid in the brain. By not sleeping, neurons continue to work, which can lead to an accumulation of beta amyloid . It’s also possible that sleep aids in the removal of waste products from the brain, including beta amyloid, the researchers commented.
During sleep, neurons shrink, creating space between cells that allows waste products to be more easily removed from the brain. If we don’t sleep, the consequence is clear.
However, more studies are needed to directly link poor sleep to risk of Alzheimer’s disease, the authors clarify, as it is not known whether a good night’s sleep can wipe out the amyloid beta buildup from a brief episode of insomnia, for example.
A future experiment could involve participants experiencing a night of sleep deprivation followed by a night of deep sleep, with brain scans detailing whether good sleep can restore brain health.
Reference: Ehsan Shokri-Kojori et al. β-Amyloid accumulation in the human brain after one night of sleep deprivation, Proceedings of the National Academy of Sciences (2018). DOI: 10.1073 / pnas.1721694115
