Researchers studied grizzly bears to gain insight into how to reverse a natural state of diabetes.
Grizzly bears are obese but not diabetic in the fall, they briefly develop the condition a few weeks into hibernation, but it is reversed when they wake up in the spring, Cell Press reported. The study demonstrated how natural biology can show us secrets of coping with disease.
When humans develop type II diabetes their cells lose the ability to respond to insulin, which helps regulate blood sugar. The researchers found that, unlike humans, insulin levels in bears don't change; the cells simply turn on or off their ability to receive the hormone. The researchers also noticed that when the grizzlies are most obese, they are most sensitive to insulin; they become this way by shutting down a protein called PTEN in their fat cells.
"This is in contrast to the common notion that obesity leads to diabetes in humans," said Dr. Kevin Corbit, of Amgen, Inc. He and his colleagues also found that grizzlies have the ability to store the fuel they need during hibernation in their fat tissue, as opposed to in their liver and muscle, which is where fat usually accumulates in other animals struggling with obesity.
The findings suggest the mechanisms that trigger obesity in some patients could also be protecting them from diabetes and vice versa. Humans with less PTEN have a "bear-like" quality; meaning they are extremely sensitive to insulin even when obese.
"Moving forward, this more sophisticated understanding of the relationship between diabetes and obesity should enable researchers not only to develop therapies targeting these mechanisms, but also to identify the appropriate patients to whom these therapies should be targeted," Dr. Corbit explained.
The article ""Three distinct states of insulin sensitivity with hibernation-specific insulin resistance" was published in the journal Cell Metabolism.
