Biglycan Plays Role in Healing Bone Fractures

Thirty years ago, biglycan was thought to be merely a structural component that imparted mechanical stability to teeth, bones, muscles, cartilage, and tendons. Re­searchers at the National In­stitute of Dental and Cranio­facial Research (NIDCR) re­cently discovered that biglycan plays a role in the healing process of broken bones, and it may further potentiate healing by promoting the formation of nutrient-delivering blood vessels after an injury. The research team as­sessed tissue samples from mouse leg fractures using micro-CT scan, x-ray, tissue staining, and gene expression studies, and they demonstrated that when broken bones started to knit back together, the level of blood vessel formation was higher in normal mice than in biglycan-deficient mice. In other words, biglycan may be necessary for blood vessel formation af­ter a fracture.

Bone morphogenetic protein-2 (BMP-2) is a therapeutic product that oral and orthopedic surgeons use during surgery to hasten bone healing. Because BMP-2 is expensive, requires a large amount to work well, and can cause adverse effects (such as tissue swelling from in­flammation and bone forming outside the intended boundary), researchers are trying to find a way to reduce the dose of BMP-2 by finding another substance to use along with it. The NIDCR team believes that biglycan might be a candidate to be combined with BMP-2 in surgical applications that re­quire the formation of bony tis­sue. By late January, these NIDCR-supported research­ers at the University of North Carolina at Chapel Hill provided the preclinical proof of this hy­pothesis. They published an article online in ad­vance of print in the Journal of Dental Research. In this article, the researchers demonstrated that low-dose BMP-2 combined with biglycan works as well as high-dose BMP-2 alone. Future research calls for comparing the biomechanical strength of normal mouse bones and those that lack biglycan. One pa­tient population that could benefit from the possible com­bination of BMP-2 and biglycan is the 30,000 Amer­icans who have a rare, inherited disease known as brittle bone disease or osteogenesis im­perfecta. People with os­teogenesis imperfecta break bones very easily, and in the future perhaps biglycan, or similar agents, could be used to help such patients recover from bone fractures.

(Source: NIDCR, Science News in Brief, March 5, 2014)