1
|
Casanova M, Schindeler A, Peacock L, Lee L, Schneider P, Little DG, Müller R. Characterization of the Developing Lacunocanalicular Network During Fracture Repair. JBMR Plus 2021; 5:e10525. [PMID: 34532613 PMCID: PMC8441443 DOI: 10.1002/jbm4.10525] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 05/23/2021] [Accepted: 06/06/2021] [Indexed: 11/09/2022] Open
Abstract
Fracture repair is a normal physiological response to bone injury. During the process of bony callus formation, a lacunocanalicular network (LCN) is formed de novo that evolves with callus remodeling. Our aim was the longitudinal assessment of the development and evolution of the LCN during fracture repair. To this end, 45 adult wild‐type C57BL/6 mice underwent closed tibial fracture surgery. Fractured and intact contralateral tibias were harvested after 2, 3, and 6 weeks of bone healing (n = 15/group). High‐resolution micro–computed tomography (μCT) and deconvolution microscopy (DV) approaches were applied to quantify lacunar number density from the calluses and intact bone. On histological sections, Goldner's trichrome staining was used to assess lacunar occupancy, fluorescein isothiocyanate staining to visualize the canalicular network, and terminal deoxynucleotidyl transferase–mediated deoxyuridine triphosphate‐biotin nick end labeling (TUNEL) staining to examine osteocyte apoptosis. Analysis of μCT scans showed progressive decreases in mean lacuna volume over time (−27% 2–3 weeks; −13% 3–6 weeks). Lacunar number density increased considerably between 2 and 3 weeks (+156%). Correlation analysis was performed, showing a positive linear relationship between canalicular number density and trabecular thickness (R2 = 0.56, p < 0.001) and an inverse relationship between mean lacuna volume and trabecular thickness (R2 = 0.57, p < 0.001). Histology showed increases in canalicular number density over time (+22% 2–3 weeks, +51% 3–6 weeks). Lacunar occupancy in new bone of the callus was high (>90%), but the old cortical bone within the fracture site appeared necrotic as it underwent resorption. In conclusion, our data shows a progressive increase in the complexity of the LCN over time during fracture healing and demonstrates that this network is initiated during the early stages of repair. Further studies are needed to address the functional importance of osteocytes in bone healing, particularly in detecting and translating the effects of micromotion in the fracture. © 2021 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.
Collapse
Affiliation(s)
| | - Aaron Schindeler
- Orthopaedic Research & Biotechnology The Children's Hospital at Westmead Westmead Australia.,Discipline of Child and Adolescent Health University of Sydney Camperdown Australia
| | - Lauren Peacock
- Orthopaedic Research & Biotechnology The Children's Hospital at Westmead Westmead Australia
| | - Lucinda Lee
- Orthopaedic Research & Biotechnology The Children's Hospital at Westmead Westmead Australia.,Discipline of Child and Adolescent Health University of Sydney Camperdown Australia
| | - Philipp Schneider
- Institute for Biomechanics ETH Zurich Zurich Switzerland.,Bioengineering Science Research Group, Faculty of Engineering and Physical Sciences University of Southampton Southampton UK.,High-Performance Vision Systems, Center for Vision, Automation & Control Austrian Institute of Technology (AIT) Vienna Austria
| | - David G Little
- Orthopaedic Research & Biotechnology The Children's Hospital at Westmead Westmead Australia.,Discipline of Child and Adolescent Health University of Sydney Camperdown Australia
| | - Ralph Müller
- Institute for Biomechanics ETH Zurich Zurich Switzerland
| |
Collapse
|
2
|
Wang Y, Chen L, Kang M, Ling L, Tian F, Won-Kim SH, Ho S, Bikle DD. The Fracture Callus Is Formed by Progenitors of Different Skeletal Origins in a Site-Specific Manner. JBMR Plus 2019; 3:e10193. [PMID: 31667451 PMCID: PMC6808225 DOI: 10.1002/jbm4.10193] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Revised: 03/05/2019] [Accepted: 03/10/2019] [Indexed: 01/05/2023] Open
Abstract
We evaluated repair following a mid‐diaphyseal fracture of the tibia in 3‐month‐old mice. We observed differences in the repair process at three different sites of the callus. Site 1: bone developing from the outer layer of the periosteum of the cortex; site 2: bone developing within the bridge/central region of the fracture; and site 3: bone developing within the marrow of the ends of broken bones. We characterized these sites by correlating datasets from X‐ray CT and histology. Correlated data demonstrated the involvement of different cells and different rates of mineralization. The origin of the progenitors and mechanism of progenitor differentiation involved at these sites was then evaluated using lineage tracing of cells expressing Prx1 and Col.2. The Prx1 progeny contributed to intramembranous bone formation (IBF) at site 1 and endochondral bone formation (EndoBF) at site 2 but not to intramedullary bone formation (IMBF) at site 3. IBF at site 1 was confirmed without a chondrocyte intermediate unlike EndoBF at site 2. Additionally, the presence of Col.2 progeny contributed to EndoBF in site 2 and IMBF in site 3 but not to IBF in site 1. However, the Col.2 progeny in IMBF in site 3 appeared to come from Col.2‐expressing osteocytes originating in the cortices of the ends of the fractured bone. In conclusion we have identified three sites of bone fracture repair that differ in their origin of cells and their mechanisms of bone formation. © 2019 The Authors JBMR Plus published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research.
Collapse
Affiliation(s)
- Yongmei Wang
- Endocrine Unit, University of California San Francisco and Veterans Affairs Medical Center San Francisco CA USA
| | - Ling Chen
- Bioengineering & Biomaterials Micro-CT and Imaging Facility University of California, San Francisco San Francisco CA USA
| | - Misun Kang
- Bioengineering & Biomaterials Micro-CT and Imaging Facility University of California, San Francisco San Francisco CA USA
| | - Lin Ling
- Endocrine Unit, University of California San Francisco and Veterans Affairs Medical Center San Francisco CA USA
| | - Faming Tian
- Endocrine Unit, University of California San Francisco and Veterans Affairs Medical Center San Francisco CA USA
| | - Sun Hee Won-Kim
- Endocrine Unit, University of California San Francisco and Veterans Affairs Medical Center San Francisco CA USA
| | - Sunita Ho
- Bioengineering & Biomaterials Micro-CT and Imaging Facility University of California, San Francisco San Francisco CA USA
| | - Daniel D Bikle
- Endocrine Unit, University of California San Francisco and Veterans Affairs Medical Center San Francisco CA USA
| |
Collapse
|
3
|
Hadjiargyrou M, Komatsu DE. The Therapeutic Potential of MicroRNAs as Orthobiologics for Skeletal Fractures. J Bone Miner Res 2019; 34:797-809. [PMID: 30866092 PMCID: PMC6536331 DOI: 10.1002/jbmr.3708] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 02/04/2019] [Accepted: 02/23/2019] [Indexed: 12/19/2022]
Abstract
The repair of a fractured bone is critical to the well-being of humans. Failure of the repair process to proceed normally can lead to complicated fractures, exemplified by either a delay in union or a complete nonunion. Both of these conditions lead to pain, the possibility of additional surgery, and impairment of life quality. Additionally, work productivity decreases, income is reduced, and treatment costs increase, resulting in financial hardship. Thus, developing effective treatments for these difficult fractures or even accelerating the normal physiological repair process is warranted. Accumulating evidence shows that microRNAs (miRNAs), small noncoding RNAs, can serve as key regulatory molecules of fracture repair. In this review, a brief description of the fracture repair process and miRNA biogenesis is presented, as well as a summary of our current knowledge of the involvement of miRNAs in physiological fracture repair, osteoporotic fractures, and bone defect healing. Further, miRNA polymorphisms associated with fractures, miRNA presence in exosomes, and miRNAs as potential therapeutic orthobiologics are also discussed. This is a timely review as several miRNA-based therapeutics have recently entered clinical trials for nonskeletal applications and thus it is incumbent upon bone researchers to explore whether miRNAs can become the next class of orthobiologics for the treatment of skeletal fractures.
Collapse
Affiliation(s)
- Michael Hadjiargyrou
- Department of Life Sciences, New York Institute of Technology, Old Westbury, NY, USA
| | - David E Komatsu
- Department of Orthopaedics, Stony Brook University, Stony Brook, NY, USA
| |
Collapse
|
4
|
de Jong JJA, Heyer FL, Arts JJC, Poeze M, Keszei AP, Willems PC, van Rietbergen B, Geusens PP, van den Bergh JPW. Fracture Repair in the Distal Radius in Postmenopausal Women: A Follow-Up 2 Years Postfracture Using HRpQCT. J Bone Miner Res 2016; 31:1114-22. [PMID: 26676839 DOI: 10.1002/jbmr.2766] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Revised: 12/03/2015] [Accepted: 12/11/2015] [Indexed: 01/08/2023]
Abstract
Fracture healing is characterized by an intense increase in modeling and remodeling of bone, which allows removal of the cast after a stable distal radius fracture within 3 to 5 weeks. However, at that time, bone strength has not recovered yet. We studied the changes in bone mineral density (BMD), microarchitecture, and bone stiffness after a distal radius fracture during a 2-year follow-up in comparison to the contralateral side and the association between the 2-year stiffness and baseline BMD, microarchitecture, and early changes in these parameters. The fractured side of 14 postmenopausal women (mean age 64 ± 8 years) with a conservatively treated distal radius fracture was scanned by high-resolution peripheral quantitative computed tomography (HRpQCT) at 1 to 2, 3 to 4, 6 to 8, and 12 weeks and 2 years postfracture. The same region contralaterally was scanned as well at the 2-year visit. BMD, microarchitecture, and stiffness parameters were determined and the fracture side was compared with the contralateral side using a linear mixed-effect model. Spearman's correlation was used to correlate the 2-year bone stiffness with baseline BMD, microarchitecture, and early 3-month changes in these parameters. Two years postfracture, cortical and trabecular thickness and torsional and bending stiffness were significantly higher at the fractured side compared with the nonfractured side (21%, 55%, 31%, and 29%, respectively, p < 0.05), whereas BMD was similar. Two-year torsional and bending stiffness correlated significantly with baseline BMD and cortical perimeter (|rho| ≥ 0.63, p < 0.016) but not with early changes in bone parameters. Using HRpQCT, this study illustrates that fracture healing is not completed by the time the cast is removed. We showed that from 6 weeks to 2 years postfracture, large changes occur in BMD, microarchitecture, and biomechanical parameters at the fractured side, which were fully recovered after 2 years in comparison to the nonfractured contralateral side. Interestingly, higher 2-year torsional and bending stiffness were associated with lower BMD and higher cortical perimeter at baseline. © 2015 American Society for Bone and Mineral Research.
Collapse
Affiliation(s)
- Joost J A de Jong
- NUTRIM School for Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, Maastricht, The Netherlands.,Department of Rheumatology, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Frans L Heyer
- NUTRIM School for Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, Maastricht, The Netherlands.,Department of Surgery, Maastricht University Medical Center, Maastricht, The Netherlands.,Department of Internal Medicine, VieCuri Medical Center, Venlo, The Netherlands
| | - Jacobus J C Arts
- Department of Orthopedic Surgery, Maastricht University Medical Center, Maastricht, The Netherlands.,CAPHRI School for Public Health and Primary Care, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Martijn Poeze
- NUTRIM School for Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, Maastricht, The Netherlands.,Department of Surgery, Maastricht University Medical Center, Maastricht, The Netherlands
| | - András P Keszei
- Department of Medical Informatics, Uniklinik RWTH Aachen University, Aachen, Germany
| | - Paul C Willems
- Department of Orthopedic Surgery, Maastricht University Medical Center, Maastricht, The Netherlands.,CAPHRI School for Public Health and Primary Care, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Bert van Rietbergen
- Faculty of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Piet P Geusens
- Department of Rheumatology, Maastricht University Medical Center, Maastricht, The Netherlands.,CAPHRI School for Public Health and Primary Care, Maastricht University Medical Center, Maastricht, The Netherlands.,Faculty of Medicine and Life Sciences, Hasselt University, Hasselt, Belgium
| | - Joop P W van den Bergh
- NUTRIM School for Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, Maastricht, The Netherlands.,Department of Rheumatology, Maastricht University Medical Center, Maastricht, The Netherlands.,Department of Internal Medicine, VieCuri Medical Center, Venlo, The Netherlands.,Faculty of Medicine and Life Sciences, Hasselt University, Hasselt, Belgium
| |
Collapse
|
5
|
Abstract
Macrophages are present in nearly all tissues and are critical for development, homeostasis, and regeneration. Resident tissue macrophages of bone, termed osteal macrophages, are recently classified myeloid cells that are distinct from osteoclasts. Osteal macrophages are located immediately adjacent to osteoblasts, regulate bone formation, and play diverse roles in skeletal homeostasis. Genetic or pharmacological modulation of macrophages in vivo results in significant bone phenotypes, and these phenotypes depend on which macrophage subsets are altered. Macrophages are also key mediators of osseous wound healing and fracture repair, with distinct roles at various stages of the repair process. A central function of macrophages is their phagocytic ability. Each day, billions of cells die in the body and efferocytosis (phagocytosis of apoptotic cells) is a critical process in both clearing dead cells and recruitment of replacement progenitor cells to maintain homeostasis. Recent data suggest a role for efferocytosis in bone biology and these new mechanisms are outlined. Finally, although macrophages have an established role in primary tumors, emerging evidence suggests that macrophages in bone support cancers which preferentially metastasize to the skeleton. Collectively, this developing area of osteoimmunology raises new questions and promises to provide novel insights into pathophysiologic conditions as well as therapeutic and regenerative approaches vital for skeletal health.
Collapse
Affiliation(s)
- Benjamin P Sinder
- Department of Periodontics and Oral Medicine, University of Michigan School of Dentistry, Ann Arbor, MI, USA
| | - Allison R Pettit
- Blood and Bone Diseases Program, Mater Research Institute–The University of Queensland, Translational Research Institute, Woolloongabba, Australia
| | - Laurie K McCauley
- Department of Periodontics and Oral Medicine, University of Michigan School of Dentistry, Ann Arbor, MI, USA
- Department of Pathology, University of Michigan, Medical School, Ann Arbor, MI, USA
| |
Collapse
|
6
|
Myers TJ, Longobardi L, Willcockson H, Temple JD, Tagliafierro L, Ye P, Li T, Esposito A, Moats-Staats BM, Spagnoli A. BMP2 Regulation of CXCL12 Cellular, Temporal, and Spatial Expression is Essential During Fracture Repair. J Bone Miner Res 2015; 30:2014-27. [PMID: 25967044 PMCID: PMC4970512 DOI: 10.1002/jbmr.2548] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Revised: 04/27/2015] [Accepted: 05/05/2015] [Indexed: 12/30/2022]
Abstract
The cellular and humoral responses that orchestrate fracture healing are still elusive. Here we report that bone morphogenic protein 2 (BMP2)-dependent fracture healing occurs through a tight control of chemokine C-X-C motif-ligand-12 (CXCL12) cellular, spatial, and temporal expression. We found that the fracture repair process elicited an early site-specific response of CXCL12(+)-BMP2(+) endosteal cells and osteocytes that was not present in unfractured bones and gradually decreased as healing progressed. Absence of a full complement of BMP2 in mesenchyme osteoprogenitors (BMP2(cKO/+)) prevented healing and led to a dysregulated temporal and cellular upregulation of CXCL12 expression associated with a deranged angiogenic response. Healing was rescued when BMP2(cKO/+) mice were systemically treated with AMD3100, an antagonist of CXCR4 and agonist for CXCR7 both receptors for CXCL12. We further found that mesenchymal stromal cells (MSCs), capable of delivering BMP2 at the endosteal site, restored fracture healing when transplanted into BMP2(cKO/+) mice by rectifying the CXCL12 expression pattern. Our in vitro studies showed that in isolated endosteal cells, BMP2, while inducing osteoblastic differentiation, stimulated expression of pericyte markers that was coupled with a decrease in CXCL12. Furthermore, in isolated BMP2(cKO/cKO) endosteal cells, high expression levels of CXCL12 inhibited osteoblastic differentiation that was restored by AMD3100 treatment or coculture with BMP2-expressing MSCs that led to an upregulation of pericyte markers while decreasing platelet endothelial cell adhesion molecule (PECAM). Taken together, our studies show that following fracture, a CXCL12(+)-BMP2(+) perivascular cell population is recruited along the endosteum, then a timely increase of BMP2 leads to downregulation of CXCL12 that is essential to determine the fate of the CXCL12(+)-BMP2(+) to osteogenesis while departing their supportive role to angiogenesis. Our findings have far-reaching implications for understanding mechanisms regulating the selective recruitment of distinct cells into the repairing niches and the development of novel pharmacological (by targeting BMP2/CXCL12) and cellular (MSCs, endosteal cells) interventions to promote fracture healing.
Collapse
Affiliation(s)
- Timothy J Myers
- Division of Endocrinology, Department of Pediatrics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Lara Longobardi
- Division of Endocrinology, Department of Pediatrics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Helen Willcockson
- Division of Endocrinology, Department of Pediatrics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Joseph D Temple
- Division of Endocrinology, Department of Pediatrics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.,Department of Pediatrics, Rush University Medical Center, Chicago, IL, USA
| | - Lidia Tagliafierro
- Division of Endocrinology, Department of Pediatrics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Ping Ye
- Division of Endocrinology, Department of Pediatrics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Tieshi Li
- Division of Endocrinology, Department of Pediatrics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.,Department of Pediatrics, Rush University Medical Center, Chicago, IL, USA
| | - Alessandra Esposito
- Division of Endocrinology, Department of Pediatrics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.,Department of Pediatrics, Rush University Medical Center, Chicago, IL, USA
| | - Billie M Moats-Staats
- Division of Endocrinology, Department of Pediatrics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Anna Spagnoli
- Division of Endocrinology, Department of Pediatrics, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.,Department of Pediatrics, Rush University Medical Center, Chicago, IL, USA
| |
Collapse
|
7
|
Wang L, Hsiao EC, Lieu S, Scott M, O'Carroll D, Urrutia A, Conklin BR, Colnot C, Nissenson RA. Loss of Gi G-Protein-Coupled Receptor Signaling in Osteoblasts Accelerates Bone Fracture Healing. J Bone Miner Res 2015; 30:1896-904. [PMID: 25917236 DOI: 10.1002/jbmr.2540] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Revised: 04/08/2015] [Accepted: 04/21/2015] [Indexed: 12/24/2022]
Abstract
G-protein-coupled receptors (GPCRs) are key regulators of skeletal homeostasis and are likely important in fracture healing. Because GPCRs can activate multiple signaling pathways simultaneously, we used targeted disruption of G(i) -GPCR or activation of G(s) -GPCR pathways to test how each pathway functions in the skeleton. We previously demonstrated that blockade of G(i) signaling by pertussis toxin (PTX) transgene expression in maturing osteoblastic cells enhanced cortical and trabecular bone formation and prevented age-related bone loss in female mice. In addition, activation of G(s) signaling by expressing the G(s) -coupled engineered receptor Rs1 in maturing osteoblastic cells induced massive trabecular bone formation but cortical bone loss. Here, we test our hypothesis that the G(i) and G(s) pathways also have distinct functions in fracture repair. We applied closed, nonstabilized tibial fractures to mice in which endogenous G(i) signaling was inhibited by PTX, or to mice with activated G(s) signaling mediated by Rs1. Blockade of endogenous G(i) resulted in a smaller callus but increased bone formation in both young and old mice. PTX treatment decreased expression of Dkk1 and increased Lef1 mRNAs during fracture healing, suggesting a role for endogenous G(i) signaling in maintaining Dkk1 expression and suppressing Wnt signaling. In contrast, adult mice with activated Gs signaling showed a slight increase in the initial callus size with increased callus bone formation. These results show that G(i) blockade and G(s) activation of the same osteoblastic lineage cell can induce different biological responses during fracture healing. Our findings also show that manipulating the GPCR/cAMP signaling pathway by selective timing of G(s) and G(i) -GPCR activation may be important for optimizing fracture repair.
Collapse
Affiliation(s)
- Liping Wang
- Endocrine Research Unit, VA Medical Center and Departments of Medicine and Physiology, University of California, San Francisco, CA
| | - Edward C Hsiao
- Department of Medicine, the Program in Craniofacial Biology, and the Institute for Human Genetics, University of California, San Francisco, CA
| | - Shirley Lieu
- Department of Orthopedic Surgery, University of California, San Francisco General Hospital, Orthopaedic Trauma Institute, San Francisco, CA
| | - Mark Scott
- Department of Orthopedic Surgery, University of California, San Francisco General Hospital, Orthopaedic Trauma Institute, San Francisco, CA
| | - Dylan O'Carroll
- Endocrine Research Unit, VA Medical Center and Departments of Medicine and Physiology, University of California, San Francisco, CA
| | - Ashley Urrutia
- Department of Medicine, the Program in Craniofacial Biology, and the Institute for Human Genetics, University of California, San Francisco, CA
| | - Bruce R Conklin
- Department of Medicine, the Program in Craniofacial Biology, and the Institute for Human Genetics, University of California, San Francisco, CA.,Gladstone Institute of Cardiovascular Disease, San Francisco, CA.,Department of Cellular and Molecular Pharmacology, University of California, San Francisco, CA
| | - Celine Colnot
- Department of Orthopedic Surgery, University of California, San Francisco General Hospital, Orthopaedic Trauma Institute, San Francisco, CA.,Institut National de la Santé et de la Recherche Médicale (INSERM; National Institute of Health and Medical Research), Unités Mixtes de Recherche (UMR) 1163, Université Paris Descartes-Sorbonne Paris Cité, Institut Imagine, Paris, France
| | - Robert A Nissenson
- Endocrine Research Unit, VA Medical Center and Departments of Medicine and Physiology, University of California, San Francisco, CA
| |
Collapse
|
8
|
Murphy CM, Schindeler A, Cantrill LC, Mikulec K, Peacock L, Little DG. PTH(1-34) Treatment Increases Bisphosphonate Turnover in Fracture Repair in Rats. J Bone Miner Res 2015; 30:1022-9. [PMID: 25484198 DOI: 10.1002/jbmr.2424] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Revised: 11/23/2014] [Accepted: 12/02/2014] [Indexed: 11/12/2022]
Abstract
Bisphosphonates (BP) are antiresorptive drugs with a high affinity for bone. Despite the therapeutic success in treating osteoporosis and metabolic bone diseases, chronic BP usage has been associated with reduced repair of microdamage and atypical femoral fracture (AFF). The latter has a poor prognosis, and although anabolic interventions such as teriparatide (PTH(1-34) ) have been suggested as treatment options, there is a limited evidence base in support of their efficacy. Because PTH(1-34) acts to increase bone turnover, we hypothesized that it may be able to increase BP in turnover in the skeleton, which, in turn, may improve bone healing. To test this, we employed a mixture of fluorescent Alexa647-labelled pamidronate (Pam) and radiolabeled (14) C-ZA (zoledronic acid). These traceable BPs were dosed to Wistar rats in models of normal growth and closed fracture repair. Rats were cotreated with saline or 25 μg/kg/d PTH(1-34) , and the effects on BP liberation and bone healing were examined by X-ray, micro-CT, autoradiography, and fluorescent confocal microscopy. Consistent with increased BP remobilization with PTH(1-34) , there was a significant decrease in fluorescence in both the long bones and in the fracture callus in treated animals compared with controls. This was further confirmed by autoradiography for (14) C-ZA. In this model of acute BP treatment, callus bone volume (BV) was significantly increased in fractured limbs, and although we noted significant decreases in callus-bound BP with PTH(1-34) , these were not sufficient to alter this BV. However, increased intracellular BP was noted in resorbing osteoclasts, confirming that, in principle, PTH(1-34) increases bone turnover as well as BP turnover.
Collapse
Affiliation(s)
- Ciara M Murphy
- Orthopaedic Research and Biotechnology Unit, The Children's Hospital at Westmead, Sydney, Australia.,Discipline of Paediatrics and Child Health, Faculty of Medicine, University of Sydney, Sydney, Australia
| | - Aaron Schindeler
- Orthopaedic Research and Biotechnology Unit, The Children's Hospital at Westmead, Sydney, Australia.,Discipline of Paediatrics and Child Health, Faculty of Medicine, University of Sydney, Sydney, Australia
| | - Laurence C Cantrill
- Orthopaedic Research and Biotechnology Unit, The Children's Hospital at Westmead, Sydney, Australia.,Discipline of Paediatrics and Child Health, Faculty of Medicine, University of Sydney, Sydney, Australia
| | - Kathy Mikulec
- Orthopaedic Research and Biotechnology Unit, The Children's Hospital at Westmead, Sydney, Australia
| | - Lauren Peacock
- Orthopaedic Research and Biotechnology Unit, The Children's Hospital at Westmead, Sydney, Australia
| | - David G Little
- Orthopaedic Research and Biotechnology Unit, The Children's Hospital at Westmead, Sydney, Australia.,Discipline of Paediatrics and Child Health, Faculty of Medicine, University of Sydney, Sydney, Australia
| |
Collapse
|