Probing for Answers About Bone Fragility.

• Position: SKELETAL ENGINEERING

With a new generation of powerful imaging technology, material science researchers at Montana State University are turning their expertise to an age-old medical problem: the weakening of bone that can lead to painful and disabling fractures among seniors and those with certain bone diseases.

The team is taking the closest look yet at the bone surrounding cells called osteocytes, which may play a central role in remodeling bone over a person's lifetime. The cells could hold the key to developing treatments for maintaining bone strength into old age, according to project leader Chelsea Heveran, assistant professor in the Department of Mechanical and Industrial Engineering.

We tend to think of bone as static, but it's actually very dynamic. If bone is like a brick wall, every day a brick is being replaced so that the wall holds up over many decades.

It is well known that other bone cells actively repair bone, but many questions remain about osteocytes, which account for more than 90% of bone cells. The average human skeleton has more than 40,000,000,000 of these cells, with a surface area equivalent to a tennis court. Small amounts of bone removed and replaced by osteocytes across this enormous network could play a major role in how bone holds up over time.

"Basically, we want to know whether osteocyte remodeling contributes to bone fracture resistance," Heveran says. "It's a challenging question because each osteocyte remodels only the very small amount of bone around it. The reason scientists haven't figured this out yet...