What would you say is the leading cause of brains being eaten? Zombies? What would you say if you knew that the leading cause was living right in your own home? What would you say if you knew it was already living in your body? Scared yet? What would you say if you found out that munching sound inside your skull was your own fault? Pounding your head against the wall won’t help, but a good night’s sleep will. A new study on mice found that sleep deprivation can cause the brain to eat itself. Would this make a great movie plot?
Researchers at the Marche Polytechnic University in Italy, lead by Michele Bellesi of the Department of Clinical and Experimental Medicine, were studying glial cells in mice. These are cells that surround neurons to provide support and insulation. They were particularly interested in astrocytes – which sounds like a Greek god or a new superhero but are actually housekeeping glial cells that repair synapses or remove worn-out ones. Synapses are the junctions between nerve cells that are the wires of the brain’s communication system. They were also watching the behavior of microglial cells, which do the dirty work of removing dead or damaged brain cells while the mice sleep. Sounds like cells you want to keep from wandering off and acting erratically, right?
Unfortunately, according to the team’s study results published in the Journal of Neuroscience, that seems to be what happens when the mice were deprived of sleep for extended periods. Observing the brain activity of mice in normal sleep patterns, Bellesi found that astrocytes were in cleanup mode for about 6 percent of the synapses. That activity increased to 8 percent when the mice were forced to stay up an additional eight hours, and hit 13.5 percent of the synapses when the mice were regularly deprived of sleep for longer periods.
We show for the first time that portions of synapses are literally eaten by astrocytes because of sleep loss.
That sounds scary, but it got worse when the team watched the microglial cells. They too were more actively dead-cell-eating during sleep deprivation. What worried Bellesi is that excessive microglial activity has been seen elsewhere.
We already know that sustained microglial activation has been observed in Alzheimer’s and other forms of neurodegeneration.
Is this a case of bad news/good news? Does the discovery that severe sleep deprivation may cause Alzheimer’s and other brain disorders mean that getting a good night’s sleep – or even more than needed – could be a prevention strategy for neurodegenerative diseases? The researchers aren’t sure. In fact, they haven’t yet determined if getting extra sleep after a few sleepless nights reverses the damage those hyperactive, brain-eating microglial cells cause.
The researchers plan to investigate how long the effects of sleep deprivation last. One thing is for sure – a lot of red-eyed, cranky mice are going to be losing their brains for science.
In the meantime, which is the better band name: The Astrocytes or The Neurodegerates? Would you go to see a movie titled Sleepless Night of the Living Dead Brain Cell Eaters?