If you're middle-aged, you might want to try a little harder to get a good night's sleep, now that new research suggests the right amount of slumber might keep Alzheimer's disease at bay.
The research was conducted in mice and is preliminary, and it may not apply to humans. Still, the possible link between sleep deprivation and Alzheimer's raises the prospect of possible treatments that target related pathways in the brain, explained study author Dr. David M. Holtzman, chairman of neurology at Washington University School of Medicine in St. Louis.
"This might be a way to delay or prevent the disease by doing something in middle life" rather than waiting until something goes wrong, Holtzman said.
The Alzheimer's Association estimates that as many as 5.3 million people in the United States have the disease, which is the country's seventh-leading cause of death. Alzheimer's disease is incurable, and although some treatments are available, they only relieve symptoms. In some cases, those symptoms include sleep problems.
Holtzman and his colleagues were not initially looking at sleep, but instead wanted to better understand how a protein clogs the brains of people with Alzheimer's. It's not clear how these clogs, known as plaques, and structures called "tangles" cause symptoms. But experts think it may have something to do with their disruption of how neurons communicate with each other.
How the study was done
The researchers developed a way to monitor the levels of the protein by the hour in both humans -- through a continual measurement of their spinal fluid via a catheter, and mice. Their findings are reported online Sept. 24 in Science.
The researchers discovered that the level of the protein went up during waking hours and fell during sleep. Holtzman said that its levels may be related to brain activity, which is higher during waking hours.
In mice, the researchers found that sleep deprivation boosted the levels of the protein, which builds up in plaques.
If a person is awake for a long time, levels of the protein might build up, Holtzman said. This could play a role in middle age because Alzheimer's disease begins to clog the brain several years before symptoms become apparent.
Dr. Nikolaos Scarmeas, an associate professor of neurology at Columbia University Medical Center in New York City, said the findings are "very impressive, extremely valid and useful."
Researchers have linked sleep problems and Alzheimer's disease before, he said, but from the perspective of the sleep problems being a symptom of the illness and a result of aging. The idea that sleep deprivation might cause Alzheimer's deserves more attention, Scarmeas said.
Holtzman said that future research should investigate how processes in the brain can be manipulated with drugs so that people get more sleep and less brain clogging.
For now, though, his advice is short and simple: "Get enough sleep in middle age." – (Randy Dotinga/HealthDay News, September 2009)
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