IE 11 is not supported. For an optimal experience visit our site on another browser.

Experts Weigh Hibernation's Healing Powers

Consider it hibernation-on-demand. Researchers plunged mice into almost a state of suspended animation and then revived them, with no apparent ill effects, in an experiment that is generating excitement because it might ultimately lead to new ways to treat critically sick people.
/ Source: The Associated Press

Consider it hibernation-on-demand. Researchers plunged mice into almost a state of suspended animation and then revived them, with no apparent ill effects, in an experiment that is generating excitement because it might ultimately lead to new ways to treat critically sick people.

It works essentially like hypothermia, in reducing the amount of oxygen needed to survive, scientists from Seattle's Fred Hutchinson Cancer Research Center report Thursday in the journal Science.

Remember those cases of people who fall into icy ponds and appear dead but recover after they're warmed up? The extreme cold preserves their brain cells from the certain death that would otherwise quickly follow oxygen deprivation.

Following that logic, doctors now sometimes use ice to chill stroke victims in hopes of minimizing damage to their brains.

Chilling might help other illnesses, too, buying time for surgeons to stop a trauma victim's hemorrhaging for example. But inducing hypothermia is difficult and can take time that patients may not have, so scientists are hunting ways to lower body temperature more effectively from the inside out.

The new experiment uses a small amount of hydrogen sulfide gas to force the body into a state of hibernation for six hours.

"We wonder whether we've stumbled on a way to access this quiescent state in a way that could be beneficial for medicine," said lead researcher Mark Roth, a cell biologist at Fred Hutchinson. "It's engaging metabolic flexibility, which heretofore was not widely recognized as something that exists."

Within minutes of inhaling the gas, the mice appeared unconscious. Their body temperatures plummeted from 98 degrees down to 59, and respiration slowed to fewer than 10 breaths a minute from 120, Roth reported.

Overall, their metabolic rate dropped by 90 percent _ meaning normal cellular activity slowed to almost a standstill, thus reducing the need for oxygen.

Fresh air revived the mice, and testing uncovered no differences in behavior or functional ability between the treated mice and untreated ones, the study concluded.

The research is "very intriguing," said Dr. David Sachs, a Harvard University transplant specialist, who said it might point to ways to help donated organs survive longer before transplant.

"Being able to decrease the metabolic rate by, they're saying, 90 percent and have an animal that's not injured by it is rather remarkable," he added.

The next step is to see whether large animals can be pushed into this hibernating state, and if doing so while an animal is ill actually helps.

"Certainly what happens in mice may not happen in larger animals," cautioned Dr. Samuel A. Tisherman, a critical-care specialist and associate director of the University of Pittsburgh's Safar Center for Resuscitation Research. He induces hypothermia by infusing animals with large amounts of cold salt water, but is considering collaborating with Roth to see if the hydrogen sulfide might help.

"It's got great potential," said Tisherman. "It conceivably could help tremendously to, specifically, help preserve organs but also help induce the hypothermia" faster.

Hydrogen sulfide, a component in sewer gas, is known to be highly toxic. But the body naturally produces some hydrogen sulfide, which helps regulate normal body temperature by adjusting how much oxygen cells burn to produce energy, Roth explained. He said the experiment used amounts considered safe.

___

On the Net:

Science: http://www.sciencemag.org