Hibernation artificially activated in potential space breakthrough | Science

Science

If discovery is possible in humans, it could be used to put astronauts in suspended animation, scientists say

In science fiction, space crews are often spared the tedium and discomfort of long-distance space travel by being placed in a state of suspended animation. Now this goal may have come a step closer after scientists showed that hibernation can be artificially triggered in rodents using ultrasonic pulses.

The progress is seen as important because the technique was effective in rats — animals that don’t naturally hibernate. This raises the prospect that humans may also maintain a rudimentary hibernation circuit in the brain that can be artificially reactivated.

“If this proves feasible in humans, we could envision astronauts wearing a helmet-like device designed to target the hypothalamus to induce a state of hypothermia and hypometabolism,” said Hong Chen, an associate professor at the Washington University in St. Louis, who did the work.

The team first identified a specific group of neurons in a deep brain region called the preoptic region of the hypothalamus that were found to be involved in regulating body temperature and metabolism during hibernation. They showed that these neurons could be artificially activated in mice using ultrasound delivered non-invasively through a helmet.

When stimulated, the mice showed a drop in body temperature of about 3°C ​​for about an hour. The mice’s metabolism also shifted from using both carbohydrates and fat for energy to fat alone, a key feature of sedation, and their heart rates dropped by about 47%, all at room temperature.

The scientists also developed an automatic closed-loop feedback system that delivered an ultrasonic pulse to keep the mice in the induced anesthesia if they showed signs of warming. This allowed the mice to be kept in the hibernation-like state for 24 hours at 33 °C. When the ultrasound system was turned off, they woke up again.

The experiments, described in the journal Nature Metabolism, showed that the same device worked in rats, which had a 1C drop in core body temperature when the same brain region was attacked. Chen said the result was “surprising and fascinating” and the team planned to test the technique in larger animals.

In humans, inducing a state of sedation has potential medical applications, with some suggesting that slowing metabolism could provide critical time for the treatment of life-threatening conditions such as heart attack and stroke. “By expanding the window for medical intervention, this technique offers promising prospects for improving patient survival,” said Chen. “In addition, the non-invasive nature of the technique opens up the possibility of developing wearable ultrasonic devices, such as helmets, for easy access in emergency situations.”

Prof Martin Jastroch of Stockholm University, who was not involved in the research, described the work as a breakthrough. “Everything they see is a repetition of what you see in nature,” he said.

“They can also do this in rats, which is pretty exciting,” he added, saying that “there’s a pretty good chance” that the same technique would theoretically work in humans. “Maybe we have some residual capacity there. Before this paper, nobody even thought about how to experiment with that in a safe way.”