Lack of sleep destroys brain cells

Experiment with mice indicates irreversible damage due to persistent lack of sleep

Persistent sleep deprivation could leave irreversible damage to the brain © SXC
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Dumb by lack of sleep? In fact, prolonged periods of lack of sleep could cause irreversible damage to the brain, as suggested by an experiment with mice. These brain cells died in a brain area important for attention and mental performance when they suffered from prolonged sleep deprivation. Now the researchers want to check whether this effect also occurs in humans - for example, shift workers.

Lack of sleep is almost commonplace today, whether through a party, learning into the night or too much work. If this only happens now and then, sleep will catch up and body and mind will recover. However, when sleep deprivation becomes chronic, for example through shift work or sleep disturbances, it can make you sick. Shift workers are more likely to suffer from diabetes, high blood pressure, but also some cancers, as studies show.

Only a few months ago, US researchers also demonstrated impressively how important controlled sleep is for our brains: while we are resting, our mind organizes the time for waste disposal. It leaches out molecular debris during the night. But what happens when the brain lacks this important break?

Damage to brain cells?

"We've always assumed that our mental capacity has fully recovered after a short and long-term lack of sleep, " said Sigrid Veasey of the University of Pennsylvania in Philadelphia and her colleagues. But some experiments showed that in some people, even after three days, sufficient sleep deficits remained in attention span and concentration. This aroused the suspicion that possibly even permanent damage to the brain cells could be left behind.

To clarify this question, Veasey and her colleagues did an experiment with mice. They considered groups of rodents either in normal sleep-wakefulness or made sure that the animals slept too little - some only for a short time, others over several weeks. Subsequently, they examined the condition of the brain cells in a specific area of ​​attention, which is important for attention and mental performance, the so-called locus coeruleus. display

Location of the locus coeruleus in the brain Diego69 / CC-by-sa 3.0

A quarter of the neurons are destroyed

The result: in the mice, who only had a short period of sleep deprivation, the brain cells managed to compensate for the lack of rest, as the researchers report: the neurons are increasingly shutting off so-called sirtuin proteins. These act on the energy metabolism of the cell and ensure that it remains in equilibrium despite overuse. This protects the cells from damage.

Unlike the M usen, suffering from prolonged sleep deprivation: With them, up to 25 percent of the neurons in the locus coeruleus perished, as the analysis showed. After a few days, the cells failed to quench enough sirtuin to balance the energy metabolism. As a result, the content of these protective proteins decreased, the neurons showed damage and finally died.

"This is the first evidence that sleep deprivation can actually trigger a loss of brain cells, " says Veasey. Obviously, the mitochondria, the power plants of the cells, can adapt briefly to increased demands due to lack of sleep. However, this will no longer work for longer periods of time.

Shiftworkers at risk?

Whether these irreversible injuries occur in humans, but still needs to be explored, emphasize the scientists. You now want to look for clues about similar damage among shiftworkers. If confirmed, these effects could even play a role in neurodegenerative diseases such as Alzheimer's or Parkinson's. For previous studies have already shown that damage to the neurons in the locus coeruleus can accelerate the course of these diseases.

At the same time, the study also raises hope: the sirtuin protein, which protects the brain cells from sleep deprivation for a short time, could also be suitable as a treatment for long-term sleep deprivation. In mice, Veasey and her colleagues have succeeded in artificially raising the sirtuin content of the neurons. "If we can use it to protect the cells, then we are on the way to a promising approach for millions of shiftworkers, " the researchers said. Until then, however, only a means of protecting our brains remains: avoid sleeping as quickly as possible. (The Journal of Neuroscience)

(University of Pennsylvania School of Medicine, 21.03.2014 - NPO)