SEATTLE How is it that some people who apparently freeze to death, with no heart rate or respiration for extended periods, can be brought back to life with no long-term negative health consequences? New findings from the laboratory of cell biologist Mark B. Roth, Ph.D., of Fred Hutchinson Cancer Research Center, may help explain the mechanics behind this widely documented phenomenon.
Reporting online ahead of the July 1 print issue of Molecular Biology of the Cell, Roth, a member of the Hutchinson Center's Basic Sciences Division, and colleagues show that two widely divergent model organisms yeast and nematodes, or garden worms can survive hypothermia, or potentially lethal cold, if they are first put into a state of suspended animation by means of anoxia, or extreme oxygen deprivation.
Roth and colleagues found that under normal conditions, yeast and nematode embryos cannot survive extreme cold. After 24 hours of exposure to temperatures just above freezing, 99 percent of the creatures expire. In contrast, if the organisms are first deprived of oxygen and thus enter a state of anoxia-induced suspended animation, 66 percent of the yeast and 97 percent of the nematode embryos will survive the cold. Once normal growth conditions are resumed upon rewarming and reintroduction of oxygen the organisms will reanimate and go on to live a normal lifespan.
A better understanding of the potentially beneficial, symbiotic relationship between low oxygen and low temperatures may one day lead to the development of improved techniques for extending the shelf life of human organs for transplantation, Roth said.
"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."
Roth's laboratory studies the potenti
|Contact: Kristen Lidke Woodward|
Fred Hutchinson Cancer Research Center