Even your bones can get fat, mouse study suggests

June 9, 2017 by Alan Mozes, Healthday Reporter

(HealthDay)—Exercise doesn't just trim your tummy. It may also improve bone thickness, boost bone quality, and whittle away the fat found inside bones, new animal research suggests.

Yes, there's fat inside your marrow.

The work with mice also uncovered potentially good news for those struggling with obesity.

Exercise—namely running—prompted shrinkage in the size of inside the bone marrow of both lean and obese mice. But, only obese mice experienced a significant drop in the amount of fat in their bones.

"Exercise strengthens bone," said study lead author Dr. Maya Styner, "and this is widely known."

"However, it appears that this is even more so in obese mice that exercise," said Styner, an assistant professor of endocrinology and metabolism at the University of North Carolina at Chapel Hill.

She added that she and her colleagues were surprised "by how significantly exercise was associated with increased bone quality in both lean and obese mice."

But, it remains to be seen if the findings will hold up in people, since "research in mice is not directly translatable to the human condition," the researchers cautioned.

Still, Styner pointed out that "the kinds of stem cells that produce bone and fat in mice are the same kind that produce bone and fat in humans."

Until now, the researchers said, it was thought that the fat in was unlike other types of body fat and didn't get used up as a source of energy during exercise.

But the new study suggests this might not be true.

The scientists collected two groups of mice for the study: 14 lean mice raised on a "normal diet" and 14 obese mice raised on a high-fat diet.

At 4 months of age, half of the obese mice and half of the lean mice were provided a running wheel.

Six weeks later, bone measurements revealed that the bones of the lean and obese rodent runners were roughly 20 percent denser, said Styner.

Fat cell size also shrank significantly in all the mice who routinely ran.

But while lean mice showed no change in the number of fat cells found in their bones, obese mice who ran lost more than half their fat cells compared with sedentary obese mice.

Running also seemed to favor when it came to improving the bone thickness.

Nevertheless, Styner said the "underlying physiology" behind fat storage remains poorly understood. And the hows and whys behind 's impact on bone fat composition remains murky.

She said her current focus is on continued animal research. But the research team said such studies might eventually point to ways of preserving and improving in patients with diabetes, arthritis, anorexia and long-term steroid use.

Dr. Robert Recker, past president of the National Osteoporosis Foundation, described the current findings as "interesting."

"However, rodents' bones behave differently than human bones," said Recker, director of the Creighton University School of Medicine's Osteoporosis Research Center in Omaha, Neb. In the normal course of events, bone growth—also called bone metabolism—unfolds in a very different way in than in people, he noted.

Still, Recker added that an effort should be made to explore bone fat dynamics in people. "This needs to be done," he said.

The study findings were published in the current issue of the Journal of Bone and Mineral Research.

Explore further: Another reason to exercise: Burning bone fat—a key to better bone health

More information: Maya Styner, M.D., assistant professor, department of medicine, division of endocrinology, University of North Carolina, Chapel Hill; Robert Recker, M.D., past president, National Osteoporosis Foundation, and director, Osteoporosis Research Center, Creighton University School of Medicine, Omaha, Neb.; May 2017, Journal of Bone and Mineral Research

There's more on bone health at the U.S. National Institutes of Health.

Related Stories

Another reason to exercise: Burning bone fat—a key to better bone health

May 18, 2017
It's a fat-burning secret anyone interested in bone health should know. For the first time, UNC School of Medicine researchers show that exercising burns the fat found within bone marrow and offers evidence that this process ...

Whole-body vibration may be as effective as regular exercise

March 15, 2017
A less strenuous form of exercise known as whole-body vibration (WBV) can mimic the muscle and bone health benefits of regular exercise in mice, according to a new study published in the Endocrine Society's journal Endocrinology.

Diabetes drug boosts bone fat and fracture risk; exercise can partially offset the effect

September 8, 2015
Inside our bones there is fat. Diabetes increases the amount of this marrow fat. And now a study from the UNC School of Medicine shows how some diabetes drugs substantially increase bone fat and thus the risk of bone fractures.

One step closer to an 'exercise pill'

April 25, 2017
Suppressing production of the protein myostatin enhances muscle mass and leads to significant improvements in markers of heart and kidney health, according to a study conducted in mice. Joshua T. Butcher, PhD, a postdoctoral ...

How a high-fat diet, exercise, and diabetes medications can change the insides of our bones

June 25, 2014
In your bones, there is fat. Why? Researchers don't know, but they have theories.

Engineered bone marrow could make transplants safer

May 8, 2017
Engineers at the University of California San Diego have developed biomimetic bone tissues that could one day provide new bone marrow for patients needing transplants.

Recommended for you

Scientists find RNA with special role in nerve healing process

August 22, 2017
Scientists may have identified a new opening to intervene in the process of healing peripheral nerve damage with the discovery that an "anti-sense" RNA (AS-RNA) is expressed when nerves are injured. Their experiments in mice ...

Mouse model of human immune system inadequate for stem cell studies

August 22, 2017
A type of mouse widely used to assess how the human immune system responds to transplanted stem cells does not reflect what is likely to occur in patients, according to a study by researchers at the Stanford University School ...

Researchers offer new targets for drugs against fatty liver disease and liver cancer

August 22, 2017
There may no silver bullet for treating liver cancer or fatty liver disease, but knowing the right targets will help scientists develop the most effective treatments. Researchers in Sweden have just identified a number of ...

Make way for hemoglobin

August 18, 2017
Every cell in the body, whether skin or muscle or brain, starts out as a generic cell that acquires its unique characteristics after undergoing a process of specialization. Nowhere is this process more dramatic than it is ...

Bio-inspired materials give boost to regenerative medicine

August 18, 2017
What if one day, we could teach our bodies to self-heal like a lizard's tail, and make severe injury or disease no more threatening than a paper cut?

Are stem cells the link between bacteria and cancer?

August 17, 2017
Gastric carcinoma is one of the most common causes of cancer-related deaths, primarily because most patients present at an advanced stage of the disease. The main cause of this cancer is the bacterium Helicobacter pylori, ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.