|Frogs may hold key to organ preservation
||[Mar. 28th, 2005|11:33 am]
Here's an interesting story that's been in the news lately:
Boris Rubinsky of UC Berkeley is studying how Wood Frogs are able to freeze and thaw. This species is routinely found north of the Arctic Circle and is actually frozen for several months out of the winter. Rubinsky has been working to increase the length of time a donor organ can survive outside the body.
The chief question was how Wood Frogs could survive the formation of ice crystals inside their bodies. The biggest problem with standard freezing lies in expanding ice crystals which rupture blood vessels and crush cells. Such damage is irreparable. Based upon his studies of the wood frog, Rubinsky came to believe that slowly cooling organs temperatures to a few degrees below freezing will preserve them without damage.
Rubinsky found Wood Frogs respond to cool temperatures by saturating theirs bodies with large amounts of glucose, which functions as a cryoprotectant. Glucose concentrations within the frogs' central organs typically soared to 100 times their original values. Still, their is a limit; a wood frog frozen to -5°C survives but lower the temperature another ten degrees and the frog will die.
Based upon his studies of the wood frog, Rubinsky has designed a pilot protocol for freezing donor organs for long-term storage prior to transplantation into a recipient. His protocol uses a computer-controlled pump designed to mimic the wood frog's practice of saturating its body with glucose.
So far, Rubinsky has succeeded in reviving rat livers after six hours of freezing at -3°C. He hopes to receive permission from the FDA to begin test on human tissues.
For more info see http://news.nationalgeographic.com/news/2005/03/0301_050301_woodfrog.html