HIBERNATING BEARS MAY HOLD a key to bone injuries in humans and their pets — and not just because the bruins can’t inflict those injuries while asleep.

Seth Donahue, an associate professor of mechanical engineering at CSU, began wondering years ago why bears don’t lose more bone mass during hibernation. After all, bones are meant to bear weight and can weaken if they don’t. It’s common for humans to suffer from “disuse osteoporosis” during extended stays in a hospital bed, for instance.

Using serum from hibernating bears, Donahue discovered a hormone called “parathyroid hormone” that protects against bone loss. Now his team is producing a synthetic version that shows promise for helping regenerate bone in people and animals suffering trauma, such as fractures and bone loss from tumor removal. In preclinical studies with mice, the synthetic parathyroid hormone promotes bone growth. Donahue is working to deliver the
synthetic hormone to the medical industry through his spinoff company, Aursos. The researchers also have added stem cells to what could become a healing protocol — removing some of the body’s own tools, multiplying them, and then injecting them to promote healing and bone regeneration.

These discoveries were possible because Donahue partnered with researchers in non-engineering fields, including Nicole Ehrhart, a CSU professor of clinical sciences who specializes in surgical oncology at the Flint Animal Cancer Center in the College of Veterinary Medicine and Biomedical Sciences. Ehrhart develops new surgical approaches to protect limbs and treat bone defects in cancer patients; her techniques are used in surgeries for people and pets.

“I’m benefitting humans, and then I get to bring that back to animals because it benefits my veterinary patients as well,” she says.

Donahue says his hormone project moved ahead because he collaborated with Ehrhart to determine how the synthetic bear hormone could be applied to treat bone in a clinical setting. The Musculoskeletal Research Program, a CSU Program of Research and Scholarly Excellence, helps spark such interdisciplinary collaboration with biomedical engineering in the College of Engineering.

“If it was just me and other engineers, we could do the experiments, but we wouldn’t have the insight into how it’s applied in the medical world,”
he says. Ehrhart tends to accept the uncertainty and variation that occur in biology, she says. Yet engineers like Donahue see patterns that benefit
biomedical research.

“I love working with engineers, because my way of thinking is very biological, and they look at the world in a very different way,” she says. “It’s a very complementary way of looking at things. We’ll run things by each other and suggest different approaches. He’ll say, ‘If we ask the question this way, we may be able to apply a formula to this and get rid of the randomness.’”