Macrophage protein shown to have major role in fracture healing

Duke Health researchers previously showed that introducing bone marrow stem cells to a bone injury can expedite healing, but the exact process was unclear. Now researchers found that macrophage and the proteins it secretes called low-density lipoprotein receptor-related protein 1 (Lrp1) can have a rejuvenating effect on tissue. These findings are published in journal Nature Communications.

After tissue injury, the body dispatches macrophages to areas of trauma, where they undergo functional changes to coordinate tissue repair. During fracture healing, macrophages are found at the fracture site. But when they’re depleted, fractures will not heal effectively. Macrophage populations and characteristics can change with aging. And in this research scientists found that a protein called low-density lipoprotein receptor-related protein 1 (Lrp1) mostly found in young macrophages possibly responsible for bone healing effects.

Finding ways to speed bone repair is a public health priority that could save both lives and health care costs. The Centers for Disease Control and Prevention reports that more than 800,000 patients a year are hospitalized because of fall injuries, including broken hips, and these hospitalizations cost an average of $30,000.

Citation: Linda Vi, Gurpreet S. Baht, Erik J. Soderblom, Heather Whetstone, Qingxia Wei, Bridgette Furman, Vijitha Puviindran, Puviindran Nadesan, Matthew Foster, Raymond Poon, James P. White, Yasuhito Yahara, Adeline Ng, Tomasa Barrientos, Marc Grynpas, M. Arthur Mosely, and Benjamin A. Alman. “Macrophage Cells Secrete Factors including LRP1 That Orchestrate the Rejuvenation of Bone Repair in Mice.” Nature Communications 9, no. 1 (2018). doi:10.1038/s41467-018-07666-0.