New Study Shows Lack of Sleep Leads to Permanent Brain Damage
We all know that sleep is one of the best ways to restore our body. For example, when we become sick, we just lie in bed and sleep all day; or after a long day bustling between class, the gym, meetings, and extracurricular activities, our body yearns to fall into a deep slumber to restore itself to its peak state. Recently, it was published that the reason sleep is so restorative is because while we sleep, cerebrospinal fluid flows more efficiently through the brain, essentially “clearing” the brain of any metabolic waste products that build up during the day (for more on this, refer to the December 9th blog post). However, just as we all understand that great feeling of satisfaction that comes after the so rarely obtained 8-9 hour sleep cycle (yes, young college-aged adults should ideally be getting 8-9 hours of sleep a night), we also can all relate to the groggy, confused, cognitively impaired state that comes after the all-night cramming and three hours of sleep, and before the double espresso from Starbucks. Until recently, this chronic state of unrest considered normal by college students, shift workers, and truck drivers, wasn’t thought to have any long lasting damage; it was considered common knowledge that catching up on sleep during weekends or vacations made up for the hours of sleep lost during finals week. However, a new study published on March 18th in the Journal of Neuroscience refutes this; the study, out of University of Pennsylvania’s Perelman School of Medicine, shows that chronic sleep loss may be much more destructive than previously thought, leading to permanent cell damage and neuronal death.
After reviewing human research that showed continued impaired cognitive function even three restoring sleep days after severe sleep deprivation, Sigrid Veasey, MD, wanted to figure out exactly if chronic sleep loss injures neurons, and if so what neurons are injured and if the injury is reversible. To do this, Veasey and her colleagues used a chronic sleep deprivation model in mice. Her team found that after periods of short-term sleep loss, locus coeruleus (LC) neurons (neurons critical for alertness and optimal cognition) upregulate protein sirtuin type 3 (SirT3), which acts to protect the neurons from injury. However, after long term sleep loss, the SirT3 response disappears; after extended long term sleep loss, the mice exhibited reduced SirT3 protein, and increased cell death – up to 25% of LC neurons were lost.
Of particular interest to Veasey was that the LC neurons adapt to short term sleep-loss, but the SirT3 response vanishes once the mice experience chronic sleep loss. This means that potentially, raising SirT3 levels in LC neurons can protect or restore them after extended sleep deprivation. Using modern techniques, it is now possible to overexpress SirT3 protein in LC neurons, and that is the next step in Veasey’s research. Veasey hopes to show that upregulating SirT3 protein can save LC neurons from dying. If she is successful, then hopefully a promising new therapy can be developed to save the neurons of overtired shift workers and college students alike. However, until that therapy arrives, it is important for all chronically over-tired people to realize that continual sleep deprivation causes physical brain damage. So, to all the college students out there: before you hit play on your fourth episode of House of Cards when it’s three in the morning, remember the show can wait! Your neurons, however, can’t wait to sleep.
CNN Health – CNN.com
Penn Medicine – Perelman School of Medicine/University of Pennsylvania Health System