EXPERT REACTION: Link between poor sleep and an Alzheimer's protein

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US researchers have discovered a link between sleep deprivation and a brain protein called beta-amyloid – the protein that ‘clumps’ together in the brains of Alzheimer’s patients. The scientists measured beta-amyloid in 20 participants after one night of rested sleep and again after one night of poor sleep. Their analysis found that sleep deprivation was associated with a significant increase in beta-amyloid compared to the well-rested night of shut-eye. Additionally, the team found this increase was associated with bad moods in the participants, as well as tiredness and difficulty staying awake.

Journal/conference: PNAS

DOI: 10.1073/pnas.1721694115

Organisation/s: National Institutes of Health, USA

Funder: This work was supported by NIH/National Institute on Alcohol Abuse and Alcoholism intramural research program (Grant Y1AA3009).

Media Release

From: PNAS

Sleep deprivation and beta-amyloid in humans

Researchers report links between sleep deprivation (SD) and beta-amyloid (Aβ) in the human brain. Aβ, a risk factor for Alzheimer’s disease (AD), is found in the interstitial fluid of the human brain. In mice, elevated Aβ has been associated with SD, but the effects of SD on Aβ burden (ABB) in the human brain remain understudied. Ehsan Shokri-Kojori and colleagues examined the effects of SD on ABB in 20 healthy participants, 22-72 years of age. Using positron emission tomography, the authors measured ABB in the participants after 1 night of rested sleep and 1 night of SD. The analysis revealed that SD was associated with a significant increase in ABB, compared with rested sleep, in the participants. Specifically, ABB increases were observed in the right hippocampus and thalamus, brain regions implicated in AD. The authors suggest that the regional increases in ABB might be linked to decreased clearance of Aβ by the glymphatic system. Additionally, SD-related increases in ABB were associated with mood worsening in the participants, including increased tiredness and difficulty staying awake following SD. The findings highlight the effects of sleep on brain function and might be relevant to AD neuropathology, according to the authors.


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Expert Reaction

These comments have been collated by the Science Media Centre to provide a variety of expert perspectives on this issue. Feel free to use these quotes in your stories. Views expressed are the personal opinions of the experts named. They do not represent the views of the SMC or any other organisation unless specifically stated.

Emeritus Professor Leon Lack is from the School of Psychology at Flinders University

This is an important study showing some of the effects in the brain resulting from sleep deprivation. It is not surprising to find effects in the brain from sleep deprivation, since we know it has very marked effects on sleepiness, cognitive performance, and mood, all of which must be a reflection of changed brain state.

It would be good to know the size of this effect. It was statistically significant; was it anything approaching the beta-amyloid burden changes in Alzheimer's disease?

The main questions are:

  1. Was this total sleep loss over 36 hours or only sleep restriction or partial sleep deprivation?
  2. Was the beta-amyloid burden response totally reversed following recovery sleep the next day or two after behavioural and psychological functioning returns to normal?
  3. Would you see the same effect after a regime of sleep restriction (only 5-6 hours sleep 4-5 nights in a row) that many people experience in their typical lives across a normal working week?
  4. Do people with insomnia experiencing 4-6 hours sleep per night show any of these elevated beta-amyloid burden effects?

My concern for the insomnia population, that I treat, is that this could become yet another research finding that could be interpreted as evidence of the potentially harmful effects of their insomnia ('insomnia will give you Alzheimer’s disease') that is likely to exacerbate their anxiety about their sleep and increase their insomnia.

Until we have the answers to the additional questions above, we can’t come to very confident conclusions about this finding.

The Australian sea lion experiences regular (about weekly) episodes of 2-3 days of complete sleep deprivation foraging in the sea for fish and then recovers lost sleep with 3-4 days of sleep and relaxation on the beach. We don’t know for certain but it doesn’t appear that they suffer any Alzheimer's disease.

Last updated: 09 Apr 2018 5:18pm

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