Why this is important
Previous studies suggest that toxic molecules involved in neurodegenerative disorders accumulate in the space between brain cells.
In this study, for instance, the researchers found that amyloid-beta, a protein that can build up in the brain and is associated with Alzheimer’s disease, cleared from the brain when the mice were asleep, suggesting sleep normally clears toxic molecules from the brain.
“These results may have broad implications for multiple neurological disorders,” said Jim Koenig, Ph.D., a program director at NINDS. “This means the cells regulating the glymphatic system may be new targets for treating a range of disorders.”
The sleep-Alzheimer’s link
But the current study also places in to context previous studies linking insomnia and dementia.
For example, in 2009 one animal study found that lack of sleep caused a build-up of amyloid beta in the brains of experimental animals.
Another published in 2010 found that amyloid beta levels in the spinal fluid of volunteers increased when they were awake and fell during sleep.
The researchers concluded that it was impaired clearance rather than overproduction of toxins that was linked to the development of Alzheimer’s.
The results of study suggested that young and middle-aged adults who suffer from insomnia and other sleep disorders may be more likely to develop Alzheimer’s in later life.
Earlier this year another study found that sleep is disrupted in people who likely have early Alzheimer’s disease but do not yet have the memory loss or the other cognitive problems characteristic of full-blown disease.
The results of the current study highlight the importance of sleep.
Put simply, ”We need sleep. It cleans up the brain,” concludes Dr. Nedergaard.