Why don't bears suffer from osteoporosis during hibernation?

This question, posed by Michigan Tech professor Dr Seth W Donahue while hiking in the Sierra Nevada, has led to the discovery of an extremely potent form of parathyroid hormone produced by black bears (Ursus americanus). In an unusual take on my usual topic of natural product therapeutics, Donahue's hope is that the ursine form of the hormone might serve as the basis for novel drugs to treat osteoporosis in humans, hibernating (on the couch) or otherwise.

Dr. Donahue's research on bears has advanced far enough toward a treatment for humans to capture commercial interest. Apjohn Group, a company founded by former Pharmacia & Upjohn executives in Kalamazoo, Mich., has an agreement with Michigan Tech to commercialize Dr. Donahue's technology. To do that, they've created a company called Aursos, a name derived from ursos, Latin for bears.

I was first alerted to the findings by the WSJ Health Blog but then learned the story came from an article written by the always-interesting, Dr Ivan Oransky. Oransky is an MD who serves as deputy editor for The Scientist who contributes regularly to a variety of scientific and lay pubications. Whenever something from Ivan pops up, it's usually on a topic in biology that is incredibly interesting or is an otherwise uncommon take on a common topic (such as this article on deer being a safety reservoir, and not a human risk, for carrying ticks).

And here's a beautiful twist in the story:

Despite the hurdles, Dr. Donahue, it turns out, wasn't the first scientist to be curious about bear bones. In 1990, a Boise, Idaho, orthopedic surgeon named Tim Floyd captured a few bears, anesthetized them and biopsied a large bone in their hips.

Dr. Floyd's findings were provocative, Dr. Donahue said, because they suggested that bears didn't lose bone during hibernation. Dr. Floyd entered private practice and didn't pursue his findings. But when he learned of Dr. Donahue's work, Dr. Floyd kicked in some of his own money to keep it rolling. Dr. Donahue also receives support from the National Institutes of Health and the Michigan Universities Commercialization Initiative.

Yes, so back to Professor Donahue - the beauty of this story illustrates the excitement of being a scientist. We are always thinking, questioning life, questioning ourselves, questioning the natural world. So here was Donahue, not a pharmacologist but a biomedical engineer, off on a strenuous but otherwise relaxing hike through the mountains. The clarity of the mountains (and perhaps the hypoxia) probably helped him associate his always-thinking mind with his natural surroundings and ask the kinds of questions that are most basic to our evolution and survival.

I hope that Donahue's work leads to a clinical drug candidate. But for me, the payoff was in just reading his story and how he came up with the idea.


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That's pretty neat! I hope mammalogists get wind of this, too.

a scientist. We are always thinking, questioning life, questioning ourselves, questioning the natural world.

Yes, and this mindset makes for a much more exciting, fulfilling and rewarding journey through life!
Dave Briggs :~)

The Donahue story is one of those great gee whiz stories that we all enjoy because it demonstrates the fun side of science. I'm wondering though, whether the real science story was the exciting eureka moment or the following years of grinding perserverence with no guarantee of success. We all have great ideas and insights but how often do we have what it takes to carry it as far as Dr. Donahue. Which brings up my second point. How the heck does somebody find the time to do this? On weekends? Was he unemployed while wondering the hills? Did he drop his current research and announce to his lab that bear hormones is the way to go? It would be interesting to find out. Lastly, I admire your ability to steer away from bad bear puns. I'm so much weaker.

Clever. It's always great to see a scientist not only smart enough to come up with the right question, but intrepid enough to hike out and get the data. Donahue deserves a ton of credit whether a product ever comes to market or not. Great post.

We are always thinking, questioning life, questioning ourselves, questioning the natural world.

Sounds a lot like my nearly six year old. Actually, it sounds like my partner and I as well, but we don't hold a candle to the boys insatiable curiosity. I often envy him that.

3+speckled, believe it or not, we scientists actually take vacations and are often physically-active! My point was that Donahue was probably just off on vacation but the mind of a scientist is always active. As for funding, I am amazed to see how much his group has done with so little support. His primary grant from NIH is called a R15 AREA (Academic Research Enhancement Award) grant, a $50K/year program to encourage research at institutions underrepresented by NIH funding with the primary goal of interest undergrads in pursuing research careers. I suspect that Donahue was already interested in such topics since his group was working in the general area of biomechanical stress on bone structure and function.

DuWayne, your point is very well-taken. In fact, if one can retain the insatiable curiosity of a six-year-old through their graduate research training, they stand to be very good researchers. I've had my own experience with my daughter's curiosity that led me to post on the source of helium, an area which I knew very little.

Since I did my undergrad chem degree at Michigan Tech, I am glad to see attention paid to this excellent but little noticed school. But I think I'll stick to rodents and not handle bears, even knocked out.