Lack of Sleep Causes Brain to Eat Itself
Lack of sleep doesn't just cause fatigue, grumpiness and depression, it also causes the brain to damage itself in ways that can become permanent over time. More specifically, the brain actually eats itself, which can lead to Alzheimer's disease and other neurological disorders.
A new study bared that astrocytes go into overdrive in the brains of lab mice that were made to undergo extended periods of sleep loss. Astrocytes are called "clean-up cells" that destroy worn-out cells, clean out the debris and refresh the brain's "wiring." Boosting these immune cells might be helpful in the short term, but it could increase the risk of dementia in the long run.
Michele Bellesi of the Italian Marche Polytechnic University said astrocytes are literally eating portions of synapses because of sleep loss. About eight percent of the synapses showed astrocyte activity in mice that lost eight hours of sleep, compared to six percent in those that enjoyed undisturbed sleep. It rose to 13.5 percent in mice that were chronically sleep-deprived.
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But an even worrisome finding is the excessive microglial activity that has been linked to a range of brain disorders like Alzheimer's and other neurodegeneration. Bellesi and her team said they will investigate if the same processes are taking place in the human brain and if getting enough rest can reverse the effects of sleeplessness.
The link between lack of sleep and Alzheimer's disease is nothing new. A 2009 laboratory study saw higher levels of toxic plaques in the brain of mice that were sleep-deprived for up to 20 hours. Toxic plaques are known to accelerate the progression of Alzheimer's disease.
Lead researcher David Holtzman theorized that the brain produces more toxic plaques when it is awake and active. When he induced the mice with an experimental drug for insomnia, the amount of plaque-forming protein in the brain was reduced. However, other experiments that cleared plaques failed to eradicate symptoms of Alzheimer's.
