( I>Brine shrimp can lie on the shore lik...)What animals can tell us about hemorrhage, organ transplants and aging

Matthew T. Andrews of the University of Minnesota Duluth and Hannah V. Carey of the University of Wisconsin School of Veterinary Medicine are the organizers of the suspended animation symposium. This and a second symposium "Molecular aspects of the mechanisms of hibernation" will include studies of animal hibernators, a form of suspended animation.

Keeping their cool

When a person suffers a stroke, heart attack or severe hypothermia, it is not the loss of blood flow (ischemia) that causes the greatest damage to the organs and tissues, explained Andrews. Instead, the greatest damage occurs when the blood flow is restored (reperfusion). Hibernating animals have significantly reduced blood flow when they hibernate, but reperfuse without injury when emerging from hibernation.

"If we can figure out how the hibernating ground squirrel does that, we might be able to avoid the damage that strokes cause in humans," Andrews said.

The ground squirrel's remarkable physiological abilities change with the seasons, Carey said. The animal's liver and heart remain viable outside the body for much longer during the hibernation season and the squirrel can tolerate a much greater loss of blood during this time. And Carey has found that this is true even when the hibernating squirrel briefly arouses from hibernation during the winter and its physiology has returned to normal.

These findings could one day extend the time we can preserve organs for transplant and give doctors time to find a suitable recipient, Carey and Andrews said. The research could also profoundly change how we treat people who are severely hypothermic or have suffered massive blood loss.

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