June 5, 2014

Poor Sleep: Precursor to Alzheimer’s?

When someone says, “If I don’t get a good night’s sleep, I’m going to lose my mind,” he may know more than you think.

A study published June 2, 1014 on NIH’s PubMed site reported a relationship between poor sleep – even a little – and the risk of developing Alzheimer’s disease.

As part of the Alzheimer, Wakefulness, and Amyloid Kinetics (AWAKE) study at the Radboud Alzheimer Center in Nijmegan, The Netherlands, scientists recruited 26 healthy, cognitively normal men (40-60 years old) who had normal sleeping habits. During the test period from June through October, 2012, the men spent one full day and night in the hospital. Half slept normally; the other half were kept awake for all 24 hours.

Subjects’ sleep and wakefulness were carefully monitored. At night, and again in the morning, samples of their cerebrospinal fluid were collected, and evaluated for the presence of the B-amyloid protein, suspected of playing a role in the development of AD. Accumulation of this amyloid plaque in the brain is a hallmark of Alzheimer’s.

Normal Sleeping Reduces B-Amyloid in the Blood
Here’s where it got interesting. Between the night and morning readings, the normal sleepers showed a 6% decrease in the level of B-amyloid in the blood. A night of regular sleep allowed their bodies to reduce the level of the potentially harmful protein. The men who were kept awake all night showed no reduction in the B-amyloid.

Researchers had to wonder: if this phenomenon occurred over just one night, imagine the impact that prolonged sleep issues would have on increasing levels of B-amyloid over time.

There was another interesting finding that suggests a relationship between sleeplessness and Alzheimer’s: areas of the brain that were most active during wakefulness were also the same areas where the likelihood of amyloid plaque build-up is the greatest.

Said geriatrician Jurgen Claassen “Another possible explanation is that the brain is purified of harmful substances during normal sleep, including beta amyloid. Disrupted sleep can get in the way of this purification.”

What's Next?
Plans are underway to conduct additional tests on a different group of human study cases, and for a longer duration.

In the meantime, the study abstract summed up conclusions this way: “Sleep deprivation, or prolonged wakefulness, interferes with a physiological morning decrease in Aβ42. We hypothesize that chronic sleep deprivation increases cerebral Aβ42 levels, which elevates the risk of Alzheimer disease."

Progress? Stay tuned.

No comments: