Putative heterotopic ossification progenitor cells derived from traumatized muscle

• Published in: Journal of orthopaedic research 2009-12, Vol.27 (12), p.1645-1651
• Main Authors: Jackson, Wesley M., Aragon, Amber B., Bulken-Hoover, Jamie D., Nesti, Leon J., Tuan, Rocky S.
• Format: Article
• Language: English
• Subjects: Alkaline Phosphatase - genetics; Alkaline Phosphatase - metabolism; Bone Marrow Cells - metabolism; Bone Marrow Cells - pathology; Cell Differentiation; Cell Proliferation; Core Binding Factor Alpha 1 Subunit - genetics; Core Binding Factor Alpha 1 Subunit - metabolism; Gene Expression; Gene Expression Profiling; heterotopic ossification; Humans; Male; mesenchymal progenitor cells; mesenchymal stem cells; Muscle, Skeletal - injuries; Muscle, Skeletal - metabolism; Muscle, Skeletal - pathology; Ossification, Heterotopic - metabolism; Ossification, Heterotopic - pathology; osteogenesis; osteoprogenitor cells; RNA, Messenger - metabolism; Stem Cells - metabolism; Stem Cells - pathology; Up-Regulation; Wounds and Injuries - metabolism; Wounds and Injuries - pathology; Young Adult
• ISSN: 0736-0266; 1554-527X
• DOI: 10.1002/jor.20924

Heterotopic ossification (HO) is a frequent complication following combat‐related trauma, but the pathogenesis of traumatic HO is poorly understood. Building on our recent identification of mesenchymal progenitor cells (MPCs) in traumatically injured muscle, the goal of this study was to evaluate the osteogenic potential of the MPCs in order to assess the role of these cells in HO formation. Compared to bone marrow‐derived mesenchymal stem cells (MSCs), a well‐characterized population of osteoprogenitor cells, the MPCs exhibited several significant differences during osteogenic differentiation and in the expression of genes related to osteogenesis. Upon osteogenic induction, MPCs showed increased alkaline phosphatase activity, production of a mineralized matrix, and up‐regulated expression of the osteoblast‐associated genes CBFA1 and alkaline phosphatase. However, MPCs did not appear to reach terminal differentiation as the expression of osteocalcin was not substantially up‐regulated. With the exception of a few genes, the osteogenic gene expression profile of traumatized muscle‐derived MPCs was comparable to that of the MSCs after osteogenic induction. These findings indicate that traumatized muscle‐derived MPCs have the potential to function as osteoprogenitor cells when exposed to the appropriate biochemical environment and are the putative osteoprogenitor cells that initiate ectopic bone formation in HO. © 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 27:1645–1651, 2009