Jan. 4, 2016
There's growing evidence that a lack of sleep can leave the brain vulnerable to Alzheimer's disease.
"Changes in sleep habits may actually be setting the stage" for dementia, says Jeffrey Iliff, a brain scientist at Oregon Health & Science University in Portland.
The brain appears to clear out toxins linked to Alzheimer's during sleep, Iliff explains. And, at least among research animals that don't get enough solid shut-eye, those toxins can build up and damage the brain.
Iliff and other scientists at OHSU are about to launch a study of people that should clarify the link between sleep problems and Alzheimer's disease in humans.
It has been clear for decades that there is some sort of link. Sleep disorders are very common among people with Alzheimer's disease.
For a long time, researchers thought this was simply because the disease was "taking out the centers of the brain that are responsible for regulating sleep," Iliff says. But two recent discoveries have suggested the relationship may be more complicated.
The first finding emerged in 2009, when researchers at Washington University in St. Louis showed that the sticky amyloid plaques associated with Alzheimer's develop more quickly in the brains of sleep-deprived mice.
Then, in 2013, Iliff was a member of a team that discovered how a lack of sleep could be speeding the development of those Alzheimer's plaques: A remarkable cleansing process takes place in the brain during deep sleep, at least in animals.
What happens, Iliff says, is "the fluid that's normally on the outside of the brain, cerebrospinal fluid — it's a clean, clear fluid — it actually begins to recirculate back into and through the brain along the outsides of blood vessels."
This process, via what's known as the glymphatic system, allows the brain to clear out toxins, including the toxins that form Alzheimer's plaques, Iliff says.
"That suggests at least one possible way that disruption in sleep may predispose toward Alzheimer's disease," he says.
Jeffrey Iliff (left), a brain scientist at Oregon Health & Science University, has been studying toxin removal in the brains of mice. He'll work with Bill Rooney, director of the university's Advanced Imaging Research Center, to enroll people in a similar study in 2016.
Courtesy of Oregon Health & Science University
To know for sure, though, researchers will have to study this cleansing process in people, which won't be easy.
Iliff studied the glymphatic system in living mice by looking through a window created in the skull. The system also involved a powerful laser and state-of-the-art microscope.
With people, "we have to find a way to see the same sort of function, but in a way that is going to be reasonably noninvasive and safe," he says.
The solution may involve one of the world's most powerful magnetic resonance imaging machines, which sits in a basement at OHSU. The MRI unit is so sensitive, it should be able to detect changes that indicate precisely when the glymphatic system gets switched on in a person's brain, says Bill Rooney, who directs the university's Advanced Imaging Research Center.
When humans enter deep sleep, and toxin removal begins, there should be a particular change in the signal coming from certain salt molecules. That would indicate that fluid has begun moving freely through the brain.
In young, healthy brains, the signal should be "robust," Rooney says, indicating that the toxin removal system is working well. In the brains of older people, and those who are likely to develop Alzheimer's, the signal should be weaker.
Rooney and Iliff have received funding from the Paul G. Allen Foundation to test their approach. They hope to begin scanning the brains of participants within a year.
One challenge, though, will be finding people able to fall asleep in the cramped and noisy tunnel of the magnetic resonance machine.
"It's a tricky thing because it's a small space," Rooney says. "But we'll make people as comfortable as possible, and we'll just follow them as they go through these natural stages of sleep."
If Rooney and Iliff are right, the experiment will greatly strengthen the argument that a lack of sleep can lead to Alzheimer's disease. It might also provide a way to identify people whose health is at risk because they aren't getting enough deep sleep, and it could pave the way to new treatments.
"It could be anything from having people exercise more regularly, or new drugs," Rooney says. "A lot of the sleep aids don't particularly focus on driving people to deep sleep stages."
Canine Cognitive Dysfunction. It may not be that others species do not experience it, but that they don't live long enough to experience it. It's only been within the last 20-30 years that it's become more common for dogs to live to be 14+. Because dogs are our companions we are aware of the changes. Mostly, animals simply stop eating... so it's possible that there is some mental dysfunction going on but it's not really been researched. Almost all pet animal research is done by pet food companies, who have little interest or need in finding out if elderly animals experience their own dementias.
t's not a "badge of honor." It's called keeping your job. I worked in the film industry where you expect to work 12 hr days & 15 hr days are more normal. On top of that you usually have a lengthy commute. Yes... people brag about how little sleep they get, etc.... but the real point of it is to constantly reinforce the idea amongst those that hire you or those that can give you leads on the next job or who might recommend you for a job that you'll be there for the long haul. If you won't, or can't, you won't be working much & so you'll get a lot of sleep, but you won't be eating much. Unfortunately, now that employers have workers over a barrel & we are dealing with a global economy, more & more people are being forced into those types of hours.
It won't change until they do make the link between lack of sleep & Alzheimer's & someone is able to connect the dots & sue a company that they worked for way back when for the extreme hours & lack of sleep that caused their Alzheimer's. To corporations, employees are disposable, because they usually don't have to deal with the chronic age related aliments that employees develop late in life, that were caused by those years on the job.
My husband has these moments," she explained to the officers. "He hears something and then his imagination takes over and pretty soon he starts to see things and then he begins to imagine the things he sees want to hurt us, No one was trying to break in. It's just that he doesn't sleep anymore. Not real sleep. Once, in the middle of the night I found him sitting in the living room in the dark. He was having a conversation with the clock. Can you imagine that?" She didn't mention the butcher knife he was clutching in his hands.
"Jake, sit down. I'll get you a pill." She desperately wanted him to calm down. It was almost morning.
"And maybe some chocolates, or better yet, a turkey sandwich on rye bread. That would be so good." He smiled sheepishly at her. "With lots of mustard please and maybe some cheese. I'm very hungry."
"What is your name?" he asked her between bites of the sandwich. The chemical deficiencies in his brain had given him an insatiable appetite. I don't know you but you seem very nice."
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The article made me think about a stoy I wrote about my father. Aside from sleep deprivation and raging insomnia, he had developed an enormous appetite, especially for chocolates as the disease progressed. Could his craving for food have been an attempt to compensate for some deficiency that was affecting his brain?
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