A donor's gift may be available, but the transportation time to the sick patient, coupled with the period that an organ can be safely preserved without damage, may indicate that those on the waiting list are victims of logistics as well as availability.
Currently, organs such as the liver or pancreas can be stored for 36 hours, though damage occurs after a day. Hibernating mammals may provide new insights to extend storage times and improve the quality of cold-stored organs. Each winter, hibernators such as ground squirrels and marmots undergo periods of torpor in which body temperature and metabolic rate are only a fraction of normal levels, without damage to their organs. For weeks at a time, hibernators maintain a body temperature close to zero degrees Celsius, which is similar to that used for human organ preservation.
Researchers at the University of Wisconsin and the University of Colorado set out to study hibernating mammals as a model for organ tolerance to extended cold preservation. The researchers are Dr. Hannah Carey at the University of Wisconsin-Madison School of Veterinary Medicine, Dr. James Southard at the UW-Madison Medical School and Dr. Sandy Martin at the University of Colorado Health Sciences Center in Denver. Their findings are being presented at Experimental Biology 2003, a conference sponsored by the American Physiological Society, being held April 11-15, 2003 at the San Diego Convention Center, San Diego, CA.
Background
Previous studies from this research team suggest that livers from hibernating ground squirrels show superior tolerance to extended cold storage when compared to a non-hibernator, such as the rat. The tolerance in summer squirrels is intermediate between the two. In their current study the researchers examined possible mechanisms by which a hibernating species may exhibit high tolerance to organ cold storage.
Methodology
The scientists and their colleagues compared harvested livers from torpid ground squirrels, from rats (which don't hibernate), and from ground squirrels in summer (when they are not hibernating). The livers were stored at 4o C for 0-72 hours in the University of Wisconsin solution, which is the preferred solution for organ storage used world-wide. Following cold storage the livers were perfused in vitro for 60 minutes at 37o C.
Results
The current and earlier studies have revealed several mechanisms that may be responsible for the superior resistance of hibernator livers to cold storage:
Conclusions
Taken together, the current and earlier studies provide exciting new directions that will help researchers identify the specific mechanisms that hibernators use to avoid tissue and organ damage during the highly altered physiology that accompanies hibernation. By fully understanding these mechanisms, these researchers believe that therapeutic advances can be developed which will protect human organs during trauma states and organ transplantation.
The American Physiological Society (APS) is one of the world's most prestigious organizations for physiological scientists. These researchers specialize in understanding the processes and functions underlying human health and disease. Founded in 1887 the Bethesda, MD-based Society has more than 10,000 members and publishes 3,800 articles in its 14 peer-reviewed journals each year.
Contact: Donna Krupa at 703-527-7357 (vm)
Or 703-967-2751 (cell) or djkrupa1@aol.com
Through April 10th, 2003
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APS Newsroom: April 11-15, 2003
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