‘Sweetgum ball-shaped’ cells could be key to bone disease treatments

Special bone cells called osteocytes are the drivers behind the body’s ability to make new bone or shave away excessive bone, scientists at the Medical College of Georgia at Augusta University found.

The discovery could lead to new experiments and research into how to treat diseases like osteoporosis and diabetes.

When people run, jump, lift weights or otherwise put physical pressure their bones, the membranes of osteocytes begin to tear.

It sounds painful, or even dangerous, but Dr. Meghan E. McGee-Lawrence said the finding is an important clue for how bones grow throughout the lifespan, including into their brittle stages in old age.

“The bone has to constantly adapt and make sure that is has the right design to withstand the loads you are going to put it through,” McGee-Lawrence said.

“If you go to the gym and exercise your muscles, they are going to get bigger and stronger and at the same time if you sit around all day your muscles are going to get weaker. Bone does the same thing.”

Osteocytes are found all throughout the bone, and each has thousands of little extensions branching off, which McGee-Lawrence said makes them look like sweetgum balls.

They manage two other cells called osteoblasts and osteoclasts. The first kind make bone and the second break down bone, though how they know when to do either has been a mystery.

McGee-Lawrence and Dr. Paul McNeil, both researchers at Augusta University, were the first to identify that tears in osteocytes spur the other types of cells to get to work.

Once the membranes tear, calcium rushes into the cells and kickstarts the bone remodeling process. Researchers even found that the osteocytes communicated with their neighboring cells to increase their own calcium levels, even if they didn’t have tears in them themselves.

McGee-Lawrence and her team received a $450,000 grant from the National Science Foundation to continue investigating the connections between osteocytes and bone remodeling, with the hope to eventually figure out new ways to ensure better bone health throughout aging and disease.

“We are wondering if bone loss with aging is due to osteocytes becoming more fragile or less able to repair as we age,” said McNeil. “If they do, you would lose them over time and, in fact, we know you do lose them.”

Now they plan to see if a 50-year-old drug called poloxamer 188, known to help repair other types of cell membranes, may be able to help osteocytes keep doing their job even after aging or disease.

“It’s a way you can influence membrane repair rates, so if we speed up how fast that tear repairs, is that going to influence the osteocytes?” McGee-Lawrence said. The answer could hopefully lead researchers to new ways of treating different ailments.

This story was originally published August 30, 2017 at 2:52 PM with the headline "‘Sweetgum ball-shaped’ cells could be key to bone disease treatments."