Researchers tackle bone healing

BLACKSBURG, VA. — Periodontal bone grafts could be a thing of the past if clinical trials of a calcium phosphate composite prove as successful as they have in the laboratory.

A team of researchers is engineering a tissue composite that will stimulate the regeneration of bone tissue in cases of severe bone loss caused by disease and cancer.

Though the research isn't out of the lab yet, mechanical engineer Brian Love, chemical engineer Aaron Goldstein and veterinary orthopedic specialist Dr. Peter Shires, Dipl. ACVS, are optimistic about their scientific trials.

"We've completed Phase I, which is testing it with osteoblasts in a petri dish," Shires says. "We've got the basic information used to stimulate bone cells in a petri dish to produce bone. But the next phase is to manipulate it, stabilize it, and try to make it more effective, more efficient and when we think it is efficient enough to test in live animals, then we will do the rats study, and the expectation is that will be in the next year to year and a half."

Though the idea of uniting calcium and phosphate as a periodontal spackling isn't new, this collaboration aims to stimulate bone formation in a stabilized substance as well as supply some of the main ingredients that go into the formation process.

"And then if we can also deliver some of the factors necessary to stimulate bone healing at the same time, then we'll have a trifecta," Shires says. "That's the hope."

How it works

The project was born out of previous research. Chemical engineer Aaron Goldstein, PhD, assistant professor at Virginia Tech, had been working in the dental field with bone to pack around loose teeth to stimulate bone formation using substances including calcium carbonate.

He believed that a stabilized phosphate substance would be better than the current substances being used, Shires says.

Enter Brian Love, a mechanical engineer and professor at Virginia Tech, who developed a way of manufacturing calcium phosphate into a form that is stable by combining it with zinc and other elements.

The result is a time-release substance that you can implant in the animal. The configuration of this material stimulates bone growth and also supplies calcium and phosphorous.

"As it disintegrates, it actually provides some of the base materials for creating new bone."

The new engineering processes also might allow the team to attach various morphogenic proteins to the substance to help stimulate bone in various parts of the formation process, Shires says.

Though there are a lot of unknowns in the ongoing product development, the basic substance is expected to enhance bone formation without any additives because the placement of the amorphous calcium phosphate material that is being stabilized will have the same effect of a bone graft without the morbidity of collecting a bone graft from a patient and implanting it somewhere else, Shires explains.

"So you can stimulate osteoblasts, differentiate with one of the bone morphogenic proteins, and then you can stimulate perhaps the maturation of the osteoblast into an osteocyte with another one, or you can stimulate osteoclast bone absorption with yet another one," he says. "So by sequencing the release of these substances from this amorphous calcium phosphate structure, we hope to be able to train or stimulate bone formation in a specific fashion. What that specific sequence is, we don't yet know."