medicalexpress | The first signs of insufficient sleep are universally familiar. There's
tiredness and fatigue, difficulty concentrating, perhaps irritability or
even tired giggles. Far fewer people have experienced the effects of
prolonged sleep deprivation, including disorientation, paranoia and
hallucinations.
Total, prolonged sleep deprivation,
however, can be fatal. While it has been reported in humans only
anecdotally, a widely cited study in rats conducted by Chicago-based
researchers in 1983 showed that a total lack of sleep inevitably leads
to death. Yet, despite decades of study, a central question has remained
unsolved: why do animals die when they don't sleep?
Now, Harvard Medical School neuroscientists have identified an
unexpected, causal link between sleep deprivation and premature death.
In a study on sleep-deprived fruit flies,
researchers found that death is always preceded by the accumulation of
molecules known as reactive oxidative species (ROS) in the gut.
When fruit flies were given antioxidant compounds
that neutralize and clear ROS from the gut, sleep-deprived flies
remained active and had normal lifespans. Additional experiments in mice
confirmed that ROS accumulate in the gut when sleep is insufficient.
The findings, published in Cell on June 4, suggest the
possibility that animals can indeed survive without sleep under certain
circumstances. The results open new avenues of study to understand the
full consequences of insufficient sleep and may someday inform the
design of approaches to counteract its detrimental effects in humans,
the authors said.
"We took an unbiased approach and searched throughout the body for
indicators of damage from sleep deprivation. We were surprised to find
it was the gut that plays a key role in causing death," said senior
study author Dragana Rogulja, assistant professor of neurobiology in the
Blavatnik Institute at HMS.
"Even more surprising, we found that premature death could be
prevented. Each morning, we would all gather around to look at the
flies, with disbelief to be honest. What we saw is that every time we
could neutralize ROS in the gut, we could rescue the flies," Rogulja
said.
Scientists have long studied sleep, a phenomenon that appears to be
fundamental for life, yet one that in many ways remains mysterious.
Almost every known animal sleeps or exhibits some form of sleeplike
behavior. Without enough of it, serious consequences ensue. In humans,
chronic insufficient sleep is associated with heart disease, type 2 diabetes, cancer, obesity, depression and many other conditions.
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