The routine breakdown of old bone during skeletal growth has an important role to play in regulating blood sugar, according to Columbia University Medical Center researchers. The process, known as resorption, goes on throughout life. It stimulates insulin release and sugar absorption, helping healthy people maintain normal blood glucose levels. The new study, published in Cell, suggests that skeletal changes could causes diabetes for some and that possible treatments for type 2 diabetes could come from the bone-insulin connection.
But what’s the precise connection between your skeleton and your insulin production? Researchers are focusing on a hormone called osteocalcin, which is activated by the process of bone being broken down and replaced. That hormone then spurs insulin production. But it doesn’t just work in one direction.
“Remarkably, insulin was discovered to favor bone resorption,” said Dr. Gerard Karsenty, chair of the Department of Genetics and Development at the Columbia medical center, in the DiabetesInControl.com article. “Hence, in a feed-forward loop it favors the activation of osteocalcin, which in turn favors insulin synthesis and secretion.”
In other words, the cycle of breaking down and replacing bone connects with and strengthens the process of releasing insulin and regulating blood sugar.
“Insulin is a street-smart molecule that takes advantage of the functional interplay between bone resorption and osteocalcin to turn on the secretion and synthesis of more insulin,” said Karsenty, the study’s lead researcher.
How about the connection to type 2 diabetes? One unexpected link is a common treatment for osteoporosis. Drugs for that condition work to stop the breakdown of bone by slowing resorption. But this research suggests such treatments could cause glucose intolerance — a risk factor for type 2.
“For people with osteoporosis, the concern is that a common treatment, bisphosphonates, which work by inhibiting bone resorption and therefore may increase glucose intolerance, could push someone with borderline glucose intolerance into full-fledged disease onset. Although more research is needed to study this further,” Karsenty said.
The researchers hope, however, that their work could lead to new treatments. “Bone may become a new target in the treatment of type 2 diabetes, the most frequent form of diabetes, as it appears to contribute strongly to glucose intolerance,” Karsenty said. “Osteocalcin could become a treatment for type 2 diabetes.”
Scientists from Harvard Medical School and the University of L’Aquila in Italy also contributed to the study.
* * *