When people have strokes or heart disease, it’s often a sign that blood (and by default oxygen) isn’t getting to the places it should in the body. If doctors don’t intervene quickly enough, the oxygen-starved cells start to die off, often leading to permanent damage, disability or even death.
Now researchers at Oregon Health and Science University are working on a way to buy valuable time for people having strokes or heart attacks. Instead of focusing on the supply of oxygen, they want to quickly reduce the amount of oxygen cells need to survive by artificially inducing a hibernation state.
Animals have evolved to hibernate to survive extreme environmental conditions like the cold of winter. Their bodies go through physiological changes designed to help them conserve energy — their temperature drops, their heartbeat slows, and because their metabolism rate drops, their cells can survive on less oxygen than they would otherwise.
The researchers have identified a way to induce the hibernation response in rats — a mechanism in the brain they believe will work in humans as well.
Normally, when a mammal gets cold, cells send signals calling for the brain to turn up the thermostat. In response, the brain triggers physical responses, like shivering, that generate body heat.
File photo of grizzly bears in Alaska. Bears and other animals hibernate in the winter to survive extreme environmental conditions.
Flickr Creative Commons, Alaska Region U.S. Fish & Wildlife Service
But when an animal goes to hibernate, the thermostat’s function reverses. Cold no longer induces shivering or any other heat-generating actions. The reversal keeps the body from trying to heat itself up, which eventually induces a hibernation-like state.
“So what we have done in these rats is we have blocked the activity of the original thermostat,” OHSU researcher Domenico Tupone told OPB’s Think Out Loud. “We have figured out a way to invert the response to cold and warm … and this mimics much more what is happening to an hibernating animal.”
The researchers eventually hope the neural trigger could be used to lower human body temperature in a controlled way. It could help patients better survive and recover from strokes, heart attacks and in other medical situations where reducing the energy needs of cells could be beneficial.
The research is published in the journal Current Biology.
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