Good sleep protects against dementia

Sufficient sleep with preventive effects against dementia and Alzheimer's

09/08/2014

Sleeping in not only has a positive effect on the mind but, according to a recent Dutch study, apparently also protects against dementia or Alzheimer's. Like the scientists around Dr. Sharon Ooms from the University of Nijmegen in the journal „JAMA Neurology“ report, led in their experiments „a night of unrestricted sleep“ a significant decrease in harmful cerebral protein deposits (beta-amyloid), which are considered to trigger Alzheimer's while sleep deprivation unfolded an opposite effect.

The researchers of the University of Nijmegen come to the conclusion that sleep deprivation or lack of sleep disturbs the breakdown of protein deposits in the brain and „Therefore, chronic sleep deprivation increases the concentration of beta-amyloid 42 peptide (Aβ42) at the cerebral level“, which in turn increases the risk of Alzheimer's disease. Sufficient sleep could therefore in turn develop a protective effect on Alzheimer's. With their study results, the Dutch researchers confirm the results from previous animal experiments on mice, however, the current study is based only on a very small sample. Further investigations to verify the results therefore seem urgently needed.

Connection between sleep and Alzheimer's disease
Recently, according to the researchers in recent studies increased evidence found that „There is an association between poor sleep and the risk of developing Alzheimer's disease.“ However, it was not yet clear whether the bad sleep is a consequence or cause of the disease. The Dutch researchers see here the effects of sleep on the beta-amyloid, the „is a key protein of Alzheimer's pathology“, as the relevant cause of the relationship. The „Doctors newspaper“ explained in this regard that in sleep a reinforced „Fluid exchange between cerebrospinal fluid and interstitium“ be determined and the harmful metabolic products are flushed out of the brain. At the same time, the production of beta-amyloid is throttled during sleep.

In sleep, harmful protein deposits are broken down
The researchers have now studied the exact effects of sleep on beta-amyloid degradation in a sample of 26 volunteer healthy men (ages 40 to 60). The participants were given a so-called intrathecal catheter, from which the scientists could take samples of the cerebrospinal fluid (CSF) at defined times. In the sleep laboratory of the University of Nijmegen, 13 subjects were allowed to sleep through one night undisturbed, while the other half of the participants had to do without sleep completely. Polysomnography was used to monitor the sleep patterns of the first groups, and in both groups the researchers took CSF samples to determine the cerebral Aβ42 concentration. In the sleeping group in the evening before falling asleep and in the morning after getting up. The other group also in the morning and in the evening and four times in between.

Sleep deprivation increases the risk of disease
Analysis of the cerebrospinal fluid samples revealed that subjects in the sleep group averaged a six percent decrease or 25.3 picograms per milliliter (pg / mL) at Aβ42 concentration during sleep, whereas sleep deprivation counteracted this decline. In addition, the decline in sleep duration has increased. When looking at the individual subjects, the largest difference between the sleep group and the sleep-depleted group was found to be 75.8 pg / ml in the Aβ42 concentration. Other protein deposits, such as the tau protein, or even the total protein level were, according to the Dutch researchers by sleep, unaffected. Lack of sleep is therefore critical, especially with regard to Aß42 deposits. Sharon Ooms and colleagues assess this as a key factor in the relationship between Alzheimer's risk and sleep behavior. (Fp)