Grizzly Bears Offer New Perspective on Diabetes-Obesity Link
In a new study, researchers examined the diabetes-obesity link in grizzly bears. The team discovered that type 2 diabetes, which appears to be reversible in these massive animals, has a biological purpose.
In this study, the researchers examined the health of grizzly bears before, during and after hibernation. The researchers found that during the fall season, grizzly bears increase their overall body weight to prepare for hibernation. During this time, even though the animals were considered obese, they were not diabetic. After a few weeks into hibernation, the researchers found that the bears became diabetic. However, when the bears woke up in the spring time, their diabetes was "cured."
The researchers explained that in bears, diabetes must serve some biological role that helps them get through hibernation, which is a period of time when they are not eating. They found that in bears, the cells are capable of turning on and off their response to insulin. In humans, type 2 diabetes occurs when the cells lose their ability to respond to insulin, which is a hormone that is responsible for regulating the blood sugar level.
The team also discovered that when the bears were the most obese, they were also the most sensitive to insulin, which meant that they were the least diabetic. Furthermore, the researchers noted that when bears consumed extra calories before hibernation, they stored the energy in fat tissue, as opposed to the liver and muscle, which are two common locations where fat builds up and causes obesity.
"This is in contrast to the common notion that obesity leads to diabetes in humans. Our results clearly and convincingly add to an emerging paradigm where diabetes and obesity-in contrast to the prevailing notion that the two always go hand-in-hand-may exist naturally on opposite ends of the metabolic spectrum," said Dr. Kevin Corbit, of Amgen reported in the press release. "While care must be taken in extrapolating preclinical findings to the care of particular patients, we believe that these and other data do support a more comprehensive and perhaps holistic approach to caring for patients with diabetes and/or obesity."
The study, "Three distinct states of insulin sensitivity with hibernation-specific insulin resistance in grizzly bears," was published in the journal, Cell Reports.