IBMS BoneKEy | BoneKEy Watch
Muscle stem cells could help bone repair after fracture
DOI:10.1038/bonekey.2015.90
Surgeons treating traumatic injury often use muscle flaps to cover damaged bone; this study investigated the impact of this muscle tissue on bone repair.
Focusing on the satellite cells (muscle stem cells), Abou-Khalil et al. assessed bone regeneration in Pax7−/− mice, which lose satellite cells from birth. Although most die within two weeks, some do survive to become adult mice. Their ability to regenerate bone after induced fracture was markedly reduced compared to wild type mice, with a lower callus size, less cartilage and a lower bone volume produced. Mice that had their satellite cells ablated at the same time as their fracture was induced showed exactly the same impairment in bone repair.
Satellite cells from muscle show increased production of bone morphogenetic proteins (BMPs), fibroblast growth factor 2 and insulin-like growth factor 1; all of these growth factors were significantly reduced in both types of satellite-deficient mice. The role of the cells in fracture healing was further confirmed by experiments in which exogenous recombinant human BMP2 was applied to mice after induced fracture; both types of satellite-deficient mice showed an improvement in bone healing.
Editor’s comment: These results provide the first functional evidence for a direct contribution of muscle to bone regeneration, which has clinical implications for the use of muscle flaps and for the role of muscle stem cell-derived growth factors in fracture repair. It would be interesting whether bone regeneration can be rescued by transplantation of Pax7+ satellite cells.
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