Polar Profiling Discoveries of the Arctic Ground Squirrel By Stacey Hilton In a first-of-its-kind study on hibernation biology, a team of Duke Anesthesiology researchers have revealed that hibernating mammals are protected against heart damage in an experimental model of cardiac surgery with the arctic ground squirrel. It’s a significant finding, published in the June 2016 issue of the journal, Anesthesiology, that the team believes will pave the way to identifying novel mechanisms of organ protection for patients undergoing cardiac surgery and transplantation. This study has made significant strides in the medical field since its inception six years ago when Dr. Mihai Podgoreanu established a transcontinental collaboration with a team of hibernation biologists at the Institute of Arctic Biology at the University of Alaska Fairbanks. The goal of this ongoing study is to develop drugs or techniques that bring about the same kinds of mechanisms in humans so people
“This integrated proteomic and metabolomic analysis has not been done before, particularly following an experimental ischemiareperfusion insult. This is indeed unique to Duke.” Mihai V. Podgoreanu, MD, FASE Associate Professor of Anesthesiology Chief, Division of Cardiothoracic Anesthesia
can protect themselves in the same way as arctic ground squirrels. “We need drugs that can protect our patients against ischemia reperfusion injury,” says Dr. Quintin Quinones, the kind of injury an organ sustains when its blood flow is limited and then subsequently restored.
(Left to Right) Dr. Mihai Podgoreanu, Dr. Quintin Quinones, Michael Smith, Dr. Zhiquan Zhang, and Dr. Qing Ma.
“We’ve learned that hibernation is an adaptation to extreme environments known to protect against that injury, a major determinant of morbidity and mortality.” These researchers have shown that proteins are expressed at different levels in the arctic ground squirrel ’s hearts and that white blood cells don’t respond to injury in the same way, which they say seems to play a major role in their ability to survive these extreme environments. They’ve learned that during most of the year, the innate immune system of the arctic ground squirrel seems to function similar to that in humans, but when they’re hibernating during the winter, it operates quite differently. When hibernators are very cold, Dr. Quinones says they can change the modifications of proteins and that is how he thinks they are able to regulate some of these differences when they’re hibernating. “We need to focus on the molecular switches that govern the change from one phenotype to the other. I think the regulation of genes through post translational modification is going to be the key to understanding that question.” According to Dr. Podgoreanu, they have identified two potential metabolic switches,
Duke Anesthesiology researchers have taken several trips to Alaska to collect the mammals and to apply their model of ischemia reperfusion to the arctic ground squirrel, one of the deepest, coldest hibernating mammals on earth that live above the Arctic Circle. Each year, they hibernate for six to nine months and remarkably are able to keep their body temperature very low, nearly stop their heart and restart it, with virtually no obvious signs of damage.