Site-Specific Load-Induced Expansion of Sca-1Prrx1 and Sca-1Prrx1 Cells in Adult Mouse Long Bone Is Attenuated With Age.

Aging is associated with significant bone loss and increased fracture risk, which has been attributed to a diminished response to anabolic mechanical loading. In adults, skeletal progenitors proliferate and differentiate into bone-forming osteoblasts in response to increasing mechanical stimuli, though the effects of aging on this response are not well-understood. Here we show that both adult and aged mice exhibit load-induced periosteal bone formation, though the response is significantly attenuated with age.

Mechanical Loading Promotes the Expansion of Primitive Osteoprogenitors and Organizes Matrix and Vascular Morphology in Long Bone Defects.

Elucidating the effects of mechanical stimulation on bone repair is crucial for optimization of the healing process. Specifically, the regulatory role that mechanical loading exerts on the osteogenic stem cell pool and vascular morphology during healing is incompletely understood. Because dynamic loading has been shown to enhance osteogenesis and repair, we hypothesized that loading induces the expansion of the osteoprogenitor cell population within a healing bone defect, leading to an increased presence of osteogenic cells.