Making Bones Young Again

Mar 09, 2016, 10:05 ET from Orthopaedic Research Society

ROSEMONT, Ill., March 9, 2016 /PRNewswire-USNewswire/ -- As we get older, our ability to heal after breaking a bone declines. This leads to a prolonged healing time and, in some instances, the bone does not heal at all, resulting in significant mobility impairments. While it is not fully understood how aging alters our capacity for fracture repair, Linda Vi, along with a team of researchers at the University of Toronto has been studying mice in the hopes of gaining a better understanding of how bone ages. The team of scientists has recently shown that old mice retain the capacity for bone repair when they are exposed to a circulation of youthful blood.

"Bone is a remarkable organ in that it has the capacity to regenerate itself," Vi explains. "It is a highly dynamic structure, laying down new bone and removing old bone, in response to changes on the forces applied to them." However, when people age, there is a dysregulation of this process. Our bones become easier to injure and are more difficult to heal. While we do not fully understand how aging alters this bone healing process, aging is associated with a decline in the abundance and activity of osteoblasts, or our bone-forming cells, during fracture healing.

The group of researchers is interested in understanding how aging alters the recruitment and activation of these osteoblasts during repair. They wondered whether old cells can be stimulated to make bone. "In our study," explains Vi, "we have identified that these improvements in fracture repair are derived from a type of immune cell, called macrophage. We show that different subtypes of macrophages are present within the healing bones of young and old mice, and that these young macrophages produce 'youthful factors', which are greatly diminished in the old macrophage population. When old mice were given just these young macrophages, the older animals showed remarkable improvements in both the pace and quality of fracture repair."

What's next for this group? Vi and her team are currently testing some of the 'youthful factors' identified in their study to learn more about their ability to promote fracture healing in old mice. "The long term goal of our work," she explains, "is to be able to develop these 'youthful factors' into a potential therapy in the treatment of fracture healing for older individuals."

Vi's work was recently presented at the Annual Meeting of the Orthopaedic Research Society. Founded in 1954, the Orthopaedic Research Society strives to be the world's leading forum for the dissemination of new musculoskeletal research findings. The musculoskeletal system provides form, support, stability, and movement to the body.

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SOURCE Orthopaedic Research Society