Lack of sleep linked to Alzheimer's disease

Lack of sleep linked to Alzheimer's - health - 24 September 2009 - New Scientist

A lack of sleep could help toxic plaques develop in the brain, accelerating the progression of Alzheimer's disease.

David Holtzman looked at how sleep affected the levels of beta-amyloid protein in mice and humans. This protein causes plaques to build up in the brain, which some think cause Alzheimer's disease by killing cells.

Holtzman's group found that beta-amyloid levels were higher in mouse brains when the mice were awake than when they were sleeping.

Lack of sleep also had an effect on plaque levels: when the mice were sleep-deprived – forced to stay awake for 20 hours of the day – they developed more plaques in their brains.
Sleep therapy

Holtzman also tried sending the mice to sleep with a drug that is being trialled for insomnia, called Almorexant. This reduced the amount of plaque-forming protein.

He suggests that sleeping for longer could limit the formation of plaques, and perhaps block it altogether.

The group also measured levels of beta-amyloid in the cerebrospinal fluid of 10 healthy men, both at night and during the day. Levels were lower at night, suggesting that sleep might also help keep levels of the plaque protein low in humans.

Holtzman reckons that when we're awake, our brains are more active, and that this may cause us to produce more beta-amyloid protein.