Just one sleepless night raises levels of a protein linked to Alzheimer’s disease in the blood of young men. The finding suggests that laying down good sleep habits at an early age may help to ward off the condition.
People with Alzheimer’s disease have clumps of two sticky proteins – beta-amyloid and tau – in their brains. Previous research has found that one night of sleep deprivation increases beta-amyloid levels in people’s brains, but less is known about the effect on tau.
Jonathan Cedernaes at Uppsala University in Sweden and his colleagues invited 15 healthy young men with an average age of 22 to a sleep clinic. They measured tau levels in the men’s blood once after they had a full night’s sleep and again after a night of no sleep.
After the sleepless night, the men had an average 17 per cent increase in tau levels in their blood, compared with a 2 per cent increase after a good night’s sleep.
It is only a small study, and we don’t know if the same thing would be seen in women. But the finding adds to growing evidence that people with disrupted or irregular sleep patterns are more likely to develop Alzheimer’s disease decades down the track, says Cedernaes. “We believe this at least provides an indication that even young individuals should take care of their sleep,” he says.
More research is needed to confirm that sleep deprivation increases tau in the brain, since levels in the blood aren’t necessarily indicative of those in the brain, says Cedernaes. Higher blood levels of tau after sleep deprivation could be a sign that the brain is clearing out the protein rather than accumulating it, he says.
If tau does indeed accumulate in the brains of young people after sleep deprivation, clinical trials should test whether optimising sleep helps to slow or prevent this build-up, and in turn lowers their risk of developing Alzheimer’s disease, says Cedernaes.
Tau is also involved in Parkinson’s disease and Creutzfeldt-Jakob disease, but the role it plays in these conditions and Alzheimer’s is unclear. Similarly, while lack of sleep has been linked to Alzheimer’s disease, it is possible that this is an early sign of the condition, rather than a contributing factor.
Journal reference: Neurology, DOI: 10.1212/WNL.0000000000008866