Nematode, commonly known as roundworm: image via WikipediaThere are several reported cases of persons who froze to death and lived to tell about it. This phenomenon has disturbed the reasonable mind for centuries, but somehow some frozen dead persons, animals, and even fruit flies have come back to their normal, healthy lives after they went through extensive periods of no heart rate or respiration.
Mark B. Roth, a cell biologist, and his colleagues at the Fred Hutchinson Cancer Research Center, study metabolic flexibility, the ability to slow down and speed up metabolic functions of the body. Being able to place persons in a state of suspended animation when traumatized by a heart attack, stroke, or bloody accident would be useful to medical personnel because it would extend patients' lives until medical care was available.
With this in mind the Hutchinson group studied yeast and nematode embryos. These embryos were not able to survive 24 hours of just-above-freezing temperatures. Roth tried the experiment again, theorizing that perhaps the embryos would return from the dead if they were severely deprived of oxygen, before freezing.
The oxygen-deprived embryos, when introduced to freezing temperatures, died. But once the warmth and oxygen were returned to their environment, 66 percent of the yeast embryos and 97 percent of the nematode embryos came back - alive and well.
Though a better understanding of the relationship between low oxygen and low temperatures is needed, both for extending life until care can be provided and for extending the life of transplant organs, Roth and colleagues made an extremely valuable contribution just by identifying that the conditions can be manipulated.
"We have found that extension of survival limits in the cold is
possible if oxygen consumption is first diminished," he said. "Our
experiments in yeast and nematodes suggest that organs may last longer
outside the body if their oxygen consumption is first reduced before
they are made cold."
The full study will appear in the July 1 print issue of Molecular Biology of the Cell.
Fred Hutchinson Cancer Research Center