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Kaymakoglu M, Ciftci E, Korkusuz P, Ozdemir E, Ege Erden M, Turhan E. Adrenomedullin has no effect on segmental bone defect healing but increases bone mineral density in rat model. ACTA ORTHOPAEDICA ET TRAUMATOLOGICA TURCICA 2023; 57:221-228. [PMID: 37823739 PMCID: PMC10724771 DOI: 10.5152/j.aott.2023.23064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Accepted: 08/23/2023] [Indexed: 10/13/2023]
Abstract
OBJECTIVE This study aimed to investigate the effect of adrenomedullin on the healing of the segmental bone defect in a rat model. METHODS Thirty-six Wistar rats were randomly divided into 6 groups based on follow-up periods and administered a dose of adrenomedullin hormone. In each group, bilaterally, a 2-mm bone defect was created at the diaphysis of the radius. Sodium chloride solution was administered to sham groups 3 times a week for 4 and 8 weeks intraperitoneally. Adrenomedullin was administered to the study groups 3 times a week: 15 μg-4 weeks, 15 μg-8 weeks, 30 μg-4 weeks, and 30 μg-8 weeks, respectively. After euthanasia, the segmental defects were evaluated by histomorphometric [new bone area (NBA)] and microtomographic [bone volume (BV), bone surface (BS), and bone mineral density (BMD)] analyses. RESULTS Although the 4- and 8-week 15 μg administered study groups had higher NBA values than the other study and control groups, the histomorphometric analysis did not reveal any statistical difference between the control and study groups regarding NBA (P > .05). In microtomographic analysis, BV was higher in the 15 μg 4-week group than 30 μg 4-week group (296.9 vs. 208.5, P=.003), and BS was lower in the 30 μg 4-week group than in the 4-week control group (695.5 vs. 1334.7, P=.005), but overall, no significant difference was found between the control and study groups (P > .05). Despite these minor differences in histomorphometric and microtomographic criteria indicating new bone formation, the BMD values of the 15 μg 8-week study group showed a significant increase compared with the control group (P=.001, respectively). CONCLUSION Adrenomedullin positively affected BMD at 15 μg, but this study could not show healing in the segmental defect site at different dose regimens. Further studies are needed to assess its effects on bone tissue trauma.
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Affiliation(s)
- Mehmet Kaymakoglu
- Department of Orthopedics and Traumatology, Izmir University of Economics, Faculty of Medicine, Izmir, Turkey
| | - Eda Ciftci
- Department of Bioengineering, Hacettepe University Institute of Natural and Applied Science, Ankara, Turkey
| | - Petek Korkusuz
- Department of Histology and Embryology, Hacettepe University Faculty of Medicine, Ankara, Turkey
| | - Erdi Ozdemir
- Department of Orthopedics and Traumatology, University of Health Sciences, Karabuk Training and Research Hospital, Karabuk, Turkey
| | | | - Egemen Turhan
- Department of Orthopedics and Traumatology, Hacettepe University Faculty of Medicine, Ankara, Turkey
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Working ZM, Morris ER, Chang JC, Coghlan RF, Johnstone B, Miclau T, Horton WA, Bahney CS. A quantitative serum biomarker of circulating collagen X effectively correlates with endochondral fracture healing. J Orthop Res 2021; 39:53-62. [PMID: 32533783 DOI: 10.1002/jor.24776] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 05/12/2020] [Accepted: 05/25/2020] [Indexed: 02/04/2023]
Abstract
Currently, there are no standardized methods for quantitatively measuring fracture repair. Physicians rely on subjective physical examinations and qualitative evaluation of radiographs to detect mineralized tissue. Since most fractures heal indirectly through a cartilage intermediate, these tools are limited in their diagnostic utility of early repair. Prior to converting to the bone, cartilage undergoes hypertrophic maturation, characterized by the deposition of a provisional collagen X matrix. The objective of this study was to characterize the kinetics of a novel collagen X biomarker relative to other biological measurements of fracture healing using a murine model of endochondral fracture repair in which a closed, mid-shaft tibia fracture was created using the classic drop-weight technique. Serum was collected 5 to 42 days post-fracture in male and female mice and compared to uninjured controls (n = 8-12). Collagen X in the serum was quantified using a recently validated ELISA-based bioassay ("Cxm")1 and compared to genetic and histological markers of fracture healing and inflammation. We found the Cxm biomarker reliably increased from baseline to a statistically unique peak 14 days post-fracture that then resolved to pre-fracture levels by 3 weeks following injury. The shape and timing of the Cxm curve followed the genetic and histological expression of collagen X but did not show a strong correlation with local inflammatory states. Assessment of fracture healing progress is crucial to making correct and timely clinical decisions for patients. This Cxm bioassay represents a minimally invasive, inexpensive technique that could provide reliable information on the biology of the fracture to significantly improve clinical care.
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Affiliation(s)
- Zachary M Working
- Department of Orthopaedic Surgery, Orthopaedic Trauma Institute, Zuckerberg San Francisco General Hospital (ZSFG), University of California, San Francisco (UCSF), San Francisco, California
- Orthopaedics and Rehabilitation, Oregon Health & Science University (OHSU), Portland, Oregon
| | - Elizabeth R Morris
- Center for Regenerative Sports Medicine, Steadman Philippon Research Institute (SPRI), Vail, Colorado
| | - Jiun Chiun Chang
- Department of Orthopaedic Surgery, Orthopaedic Trauma Institute, Zuckerberg San Francisco General Hospital (ZSFG), University of California, San Francisco (UCSF), San Francisco, California
| | - Ryan F Coghlan
- Shriners Hospitals for Children, Research Center, Portland, Oregon
| | - Brian Johnstone
- Orthopaedics and Rehabilitation, Oregon Health & Science University (OHSU), Portland, Oregon
| | - Theodore Miclau
- Department of Orthopaedic Surgery, Orthopaedic Trauma Institute, Zuckerberg San Francisco General Hospital (ZSFG), University of California, San Francisco (UCSF), San Francisco, California
| | - William A Horton
- Shriners Hospitals for Children, Research Center, Portland, Oregon
| | - Chelsea S Bahney
- Department of Orthopaedic Surgery, Orthopaedic Trauma Institute, Zuckerberg San Francisco General Hospital (ZSFG), University of California, San Francisco (UCSF), San Francisco, California
- Center for Regenerative Sports Medicine, Steadman Philippon Research Institute (SPRI), Vail, Colorado
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Xie J, Liu D, Wang H, Long H, Zhu Y, Hu Y, Zeng M. Effects of topical mechanical stability on the formation of Masquelet membrane in a rabbit radial defect model. Sci Rep 2020; 10:18939. [PMID: 33144701 PMCID: PMC7609590 DOI: 10.1038/s41598-020-76112-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2020] [Accepted: 10/23/2020] [Indexed: 12/24/2022] Open
Abstract
The exact mechanism of Masquelet technique is unknown. This study intends to explore the effects of topical mechanical stability on the formation of Masquelet membrane. Segmental radius shaft defect was created in all rabbits, which were filled with polymethylmethacrylate (PMMA) in Non-fixation group, and with PMMA fixed with plates in Fixation group, and subjected to no disposal in control group. The topical stability of PMMA and plates were monitored via X-ray and mechanical test. And the membranes were excised for further Histological, IHC and Western-Blotting analysis 4 and 6 weeks post-operatively. X-ray revealed no sign of plates loosening, or shift of PMMA. Mechanical tests revealed superior topical stability by plates. Pathological examinations suggested that vascularized and osteogenic membranes were formed around PMMA. IHC and Western-Blotting analysis revealed that both Fixation and Non-fixation group exerted significant effects on the expression of Ki67, COL I, and CD31 positive cells, as well as the protein expression of osteogenic (RUNX2, ALP) and angiogenic (VEGFA, TGF-β1) factors. And compared with membrane in Non-fixation group, Fixing PMMA spacer with plates caused a significant increase in osteogenic and angiogenic expression. This study indicates that rigid fixation provided by plate in Masquelet technique positively alters the quality of membrane formed surrounding PMMA, in terms of significantly osteogenic and angiogenic potential.
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Affiliation(s)
- Jie Xie
- Department of Orthopedics, Xiangya Hospital, Central South University, No. 87 Xiangya Road, Changsha, 410008, Hunan, China
| | - Donghao Liu
- Department of Orthopedics, Xiangya Hospital, Central South University, No. 87 Xiangya Road, Changsha, 410008, Hunan, China
| | - Haoyi Wang
- Department of Orthopedics, Xiangya Hospital, Central South University, No. 87 Xiangya Road, Changsha, 410008, Hunan, China
| | - Haitao Long
- Department of Orthopedics, Xiangya Hospital, Central South University, No. 87 Xiangya Road, Changsha, 410008, Hunan, China
| | - Yong Zhu
- Department of Orthopedics, Xiangya Hospital, Central South University, No. 87 Xiangya Road, Changsha, 410008, Hunan, China
| | - Yihe Hu
- Department of Orthopedics, Xiangya Hospital, Central South University, No. 87 Xiangya Road, Changsha, 410008, Hunan, China
| | - Min Zeng
- Department of Orthopedics, Xiangya Hospital, Central South University, No. 87 Xiangya Road, Changsha, 410008, Hunan, China.
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Lin MC, Hu D, Marmor M, Herfat ST, Bahney CS, Maharbiz MM. Smart bone plates can monitor fracture healing. Sci Rep 2019; 9:2122. [PMID: 30765721 PMCID: PMC6375940 DOI: 10.1038/s41598-018-37784-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Accepted: 12/07/2018] [Indexed: 11/08/2022] Open
Abstract
There are currently no standardized methods for assessing fracture healing, with physicians relying on X-rays which are only useful at later stages of repair. Using in vivo mouse fracture models, we present the first evidence that microscale instrumented implants provide a route for post-operative fracture monitoring, utilizing electrical impedance spectroscopy (EIS) to track the healing tissue with high sensitivity. In this study, we fixed mouse long bone fractures with external fixators and bone plates. EIS measurements taken across two microelectrodes within the fracture gap were able to track longitudinal differences between individual mice with good versus poor healing. We additionally present an equivalent circuit model that combines the EIS data to classify fracture repair states. Lastly, we show that EIS measurements strongly correlated with standard quantitative µCT values and that these correlations validate clinically-relevant operating frequencies for implementation of this technique. These results demonstrate that EIS can be integrated into current fracture management strategies such as bone plating, providing physicians with quantitative information about the state of fracture repair to guide clinical decision-making for patients.
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Affiliation(s)
- Monica C Lin
- Department of Bioengineering, University of California, Berkeley, CA, 94720, USA.
| | - Diane Hu
- UCSF Orthopaedic Trauma Institute, Zuckerberg San Francisco General Hospital, San Francisco, CA, 94110, USA
| | - Meir Marmor
- UCSF Orthopaedic Trauma Institute, Zuckerberg San Francisco General Hospital, San Francisco, CA, 94110, USA
| | - Safa T Herfat
- UCSF Orthopaedic Trauma Institute, Zuckerberg San Francisco General Hospital, San Francisco, CA, 94110, USA
| | - Chelsea S Bahney
- Department of Bioengineering, University of California, Berkeley, CA, 94720, USA
- UCSF Orthopaedic Trauma Institute, Zuckerberg San Francisco General Hospital, San Francisco, CA, 94110, USA
- Center for Regenerative Sports Medicine, Steadman Philippon Research Institute, Vail, CO, 81657, USA
| | - Michel M Maharbiz
- Department of Bioengineering, University of California, Berkeley, CA, 94720, USA
- Department of Electrical Engineering and Computer Science, University of California, Berkeley, CA, 94720, USA
- Chan Zuckerberg Biohub, San Francisco, CA, 94158, USA
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Ning B, Zhao Y, Buza JA, Li W, Wang W, Jia T. Surgically‑induced mouse models in the study of bone regeneration: Current models and future directions (Review). Mol Med Rep 2017; 15:1017-1023. [PMID: 28138711 PMCID: PMC5367352 DOI: 10.3892/mmr.2017.6155] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2015] [Accepted: 12/13/2016] [Indexed: 01/17/2023] Open
Abstract
Bone regeneration has been extensively studied over the past several decades. The surgically‑induced mouse model is the key animal model for studying bone regeneration, of the various research strategies used. These mouse models mimic the trauma and recovery processes in vivo and serve as carriers for tissue engineering and gene modification to test various therapies or associated genes in bone regeneration. The present review introduces a classification of surgically induced mouse models in bone regeneration, evaluates the application and value of these models and discusses the potential development of further innovations in this field in the future.
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Affiliation(s)
- Bin Ning
- Department of Orthopedic Surgery, Jinan Central Hospital, Shandong University, Jinan, Shandong 250013, P.R. China
| | - Yunpeng Zhao
- Department of Orthopedic Surgery, Qilu Hospital, Shandong University, Jinan, Shandong 250012, P.R. China
| | - John A Buza
- Department of Orthopedic Surgery, New York University Medical Center, New York, NY 10003, USA
| | - Wei Li
- Department of Orthopedic Surgery, Jinan Central Hospital, Shandong University, Jinan, Shandong 250013, P.R. China
| | - Wenzhao Wang
- Department of Orthopedic Surgery, Jinan Central Hospital, Shandong University, Jinan, Shandong 250013, P.R. China
| | - Tanghong Jia
- Department of Orthopedic Surgery, Jinan Central Hospital, Shandong University, Jinan, Shandong 250013, P.R. China
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Intramembranous bone regeneration and implant placement using mechanical femoral marrow ablation: rodent models. BONEKEY REPORTS 2016; 5:837. [PMID: 27648259 DOI: 10.1038/bonekey.2016.61] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Accepted: 07/19/2016] [Indexed: 12/16/2022]
Abstract
In this paper, we provide a detailed protocol for a model of long bone mechanical marrow ablation in the rodent, including surgical procedure, anesthesia, and pre- and post-operative care. In addition, frequently used experimental end points are briefly discussed. This model was developed to study intramembranous bone regeneration following surgical disruption of the marrow contents of long bones. In this model, the timing of the appearance of bone formation and remodeling is well-characterized and therefore the model is well-suited to evaluate the in vivo effects of various agents which influence these processes. When biomaterials such as tissue engineering scaffolds or metal implants are placed in the medullary cavity after marrow ablation, end points relevant to tissue engineering and implant fixation can also be analyzed. By sharing a detailed protocol, we hope to improve inter-laboratory reproducibility.
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Bahney CS, Jacobs L, Tamai R, Hu D, Luan TF, Wang M, Reddy S, Park M, Limburg S, Kim HT, Marcucio R, Kuo AC. Promoting Endochondral Bone Repair Using Human Osteoarthritic Articular Chondrocytes. Tissue Eng Part A 2016; 22:427-35. [PMID: 26830207 DOI: 10.1089/ten.tea.2014.0705] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
INTRODUCTION Current tissue engineering strategies to heal critical-size bone defects through direct bone formation are limited by incomplete integration of grafts with host bone and incomplete graft vascularization. An alternative strategy for bone regeneration is the use of cartilage grafts that form bone through endochondral ossification. Endochondral cartilages stimulate angiogenesis and are remodeled into bone, but are found in very small quantities in growth plates and healing fractures. We sought to develop engineered endochondral cartilage grafts using osteoarthritic (OA) articular chondrocytes as a cell source. Such chondrocytes often undergo hypertrophy, which is a characteristic of endochondral cartilages. MATERIALS AND METHODS We compared the ability of unmodified human OA (hOA) cartilage and cartilage grafts formed in vitro from hOA chondrocytes to undergo endochondral ossification in mice. Scaffold-free engineered chondrocyte grafts were generated by pelleting chondrocytes, followed by culture with transforming growth factor-β1 (TGF-β1) and bone morphogenetic protein 4. Samples derived from either primary or passaged chondrocytes were implanted subcutaneously into immunocompromised mice. Grafts derived from passaged chondrocytes from three patients were implanted into critical-size tibial defects in mice. Bone formation was assessed with histology after 4 weeks of implantation. The composition of tibial repair tissue was quantified with histomorphometry. RESULTS Engineered cartilage grafts generated from passaged OA chondrocytes underwent endochondral ossification after implantation either subcutaneously or in bone. Cartilage grafts integrated with host bone at 15 out of 16 junctions. Grafts variably remodeled into woven bone, with the proportion of bony repair tissue in tibial defects ranging from 22% to 85% (average 48%). Bony repair tissue bridged the tibial defects in half of the animals. In contrast, unmodified OA cartilage and engineered grafts formed from primary chondrocytes did not undergo endochondral ossification in vivo. CONCLUSIONS hOA chondrocytes can adopt an endochondral phenotype after passaging and TGF-β superfamily treatment. Engineered endochondral cartilage grafts can integrate with host bone, undergo ossification, and heal critical-size long-bone defects in a mouse model. However, additional methods to further enhance ossification of these grafts are required before the clinical translation of this approach.
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Affiliation(s)
- Chelsea S Bahney
- 1 The Orthopaedic Trauma Institute, San Francisco General Hospital, University of California , San Francisco, San Francisco, California
| | - Linsey Jacobs
- 2 San Francisco Veterans Affairs Medical Center, University of California , San Francisco, San Francisco, California
| | - Robert Tamai
- 2 San Francisco Veterans Affairs Medical Center, University of California , San Francisco, San Francisco, California
| | - Diane Hu
- 1 The Orthopaedic Trauma Institute, San Francisco General Hospital, University of California , San Francisco, San Francisco, California
| | - Tammy F Luan
- 2 San Francisco Veterans Affairs Medical Center, University of California , San Francisco, San Francisco, California
| | - Miqi Wang
- 2 San Francisco Veterans Affairs Medical Center, University of California , San Francisco, San Francisco, California
| | - Sanjay Reddy
- 2 San Francisco Veterans Affairs Medical Center, University of California , San Francisco, San Francisco, California
| | - Michelle Park
- 2 San Francisco Veterans Affairs Medical Center, University of California , San Francisco, San Francisco, California
| | - Sonja Limburg
- 2 San Francisco Veterans Affairs Medical Center, University of California , San Francisco, San Francisco, California
| | - Hubert T Kim
- 2 San Francisco Veterans Affairs Medical Center, University of California , San Francisco, San Francisco, California
| | - Ralph Marcucio
- 1 The Orthopaedic Trauma Institute, San Francisco General Hospital, University of California , San Francisco, San Francisco, California
| | - Alfred C Kuo
- 2 San Francisco Veterans Affairs Medical Center, University of California , San Francisco, San Francisco, California
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Lybrand K, Bragdon B, Gerstenfeld L. Mouse models of bone healing: fracture, marrow ablation, and distraction osteogenesis. ACTA ACUST UNITED AC 2015; 5:35-49. [PMID: 25727199 DOI: 10.1002/9780470942390.mo140161] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Three commonly used murine surgical models of bone healing [closed fracture with intramedullary fixation, distraction osteogenesis (DO), and marrow ablation by reaming] are presented. Detailed surgical protocols for each model are outlined. The nature of the regenerative processes and the types of research questions that may be addressed with these models are briefly outlined. The relative strengths and weaknesses of these models are compared to a number of other surgical models that are used to address similar research questions.
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Affiliation(s)
- Kyle Lybrand
- Orthopaedic Research Laboratory, Boston University School of Medicine, Boston, Massachusetts.,Department of Orthopaedic Surgery, Boston Medical Center, Boston, Massachusetts
| | - Beth Bragdon
- Orthopaedic Research Laboratory, Boston University School of Medicine, Boston, Massachusetts
| | - Louis Gerstenfeld
- Orthopaedic Research Laboratory, Boston University School of Medicine, Boston, Massachusetts
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Induction of fully stabilized cortical bone defects to study intramembranous bone regeneration. Methods Mol Biol 2015; 1226:183-92. [PMID: 25331051 PMCID: PMC4429531 DOI: 10.1007/978-1-4939-1619-1_14] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Bone is a regenerative tissue with an innate ability to self-remodel in response to environmental stimuli and the need to repair damage. Rodent models of fracture healing, and in particular genetic mouse models, can be used to study the contributions of specific molecular switches to skeletal repair, as well as to recreate and exacerbate biological development and repair mechanisms in postnatal skeletons. Here, we describe methodology for producing fully stabilized, single-cortex defects in mouse femurs to study mechanisms of intramembranous bone regeneration.
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Abstract
The most common procedure that has been developed for use in rats and mice to model fracture healing is described. The nature of the regenerative processes that may be assessed and the types of research questions that may be addressed with this model are briefly outlined. The detailed surgical protocol to generate closed simple transverse fractures is presented, and general considerations when setting up an experiment using this model are described.
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Bahney CS, Hu DP, Taylor AJ, Ferro F, Britz HM, Hallgrimsson B, Johnstone B, Miclau T, Marcucio RS. Stem cell-derived endochondral cartilage stimulates bone healing by tissue transformation. J Bone Miner Res 2014; 29:1269-82. [PMID: 24259230 PMCID: PMC4802866 DOI: 10.1002/jbmr.2148] [Citation(s) in RCA: 135] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Revised: 10/25/2013] [Accepted: 11/12/2013] [Indexed: 12/21/2022]
Abstract
Although bone has great capacity for repair, there are a number of clinical situations (fracture non-unions, spinal fusions, revision arthroplasty, segmental defects) in which auto- or allografts attempt to augment bone regeneration by promoting osteogenesis. Critical failures associated with current grafting therapies include osteonecrosis and limited integration between graft and host tissue. We speculated that the underlying problem with current bone grafting techniques is that they promote bone regeneration through direct osteogenesis. Here we hypothesized that using cartilage to promote endochondral bone regeneration would leverage normal developmental and repair sequences to produce a well-vascularized regenerate that integrates with the host tissue. In this study, we use a translational murine model of a segmental tibia defect to test the clinical utility of bone regeneration from a cartilage graft. We further test the mechanism by which cartilage promotes bone regeneration using in vivo lineage tracing and in vitro culture experiments. Our data show that cartilage grafts support regeneration of a vascularized and integrated bone tissue in vivo, and subsequently propose a translational tissue engineering platform using chondrogenesis of mesenchymal stem cells (MSCs). Interestingly, lineage tracing experiments show the regenerate was graft derived, suggesting transformation of the chondrocytes into bone. In vitro culture data show that cartilage explants mineralize with the addition of bone morphogenetic protein (BMP) or by exposure to human vascular endothelial cell (HUVEC)-conditioned medium, indicating that endothelial cells directly promote ossification. This study provides preclinical data for endochondral bone repair that has potential to significantly improve patient outcomes in a variety of musculoskeletal diseases and injuries. Further, in contrast to the dogmatic view that hypertrophic chondrocytes undergo apoptosis before bone formation, our data suggest cartilage can transform into bone by activating the pluripotent transcription factor Oct4A. Together these data represent a paradigm shift describing the mechanism of endochondral bone repair and open the door for novel regenerative strategies based on improved biology.
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Affiliation(s)
- Chelsea S Bahney
- University of California, San Francisco (UCSF) & San Francisco General Hospital (SFGH), Orthopaedic Trauma Institute, 2550 23 Street, Building 9, 3 Floor, San Francisco, CA 94110
- Oregon Health & Science University, Department of Orthopaedics & Rehabilitation, OP31, 3181 SW Sam Jackson Road, Portland, OR 97239, Phone: (503) 494-9505, Fax: (503) 494-5050
| | - Diane P Hu
- University of California, San Francisco (UCSF) & San Francisco General Hospital (SFGH), Orthopaedic Trauma Institute, 2550 23 Street, Building 9, 3 Floor, San Francisco, CA 94110
| | - Aaron J Taylor
- University of California, San Francisco (UCSF) & San Francisco General Hospital (SFGH), Orthopaedic Trauma Institute, 2550 23 Street, Building 9, 3 Floor, San Francisco, CA 94110
| | - Federico Ferro
- University of California, San Francisco (UCSF) & San Francisco General Hospital (SFGH), Orthopaedic Trauma Institute, 2550 23 Street, Building 9, 3 Floor, San Francisco, CA 94110
| | - Hayley M Britz
- University of Calgary, Department of Cell Biology and Anatomy, McCaig Bone and Joint Institute, 3330 Hospital Drive, NW, Calgary, AB, Canada T2N 4N1, Tel: (403) 220-8632, Fax: (403) 210-3829
| | - Benedikt Hallgrimsson
- University of Calgary, Department of Cell Biology and Anatomy, McCaig Bone and Joint Institute, 3330 Hospital Drive, NW, Calgary, AB, Canada T2N 4N1, Tel: (403) 220-8632, Fax: (403) 210-3829
| | - Brian Johnstone
- Oregon Health & Science University, Department of Orthopaedics & Rehabilitation, OP31, 3181 SW Sam Jackson Road, Portland, OR 97239, Phone: (503) 494-9505, Fax: (503) 494-5050
| | - Theodore Miclau
- University of California, San Francisco (UCSF) & San Francisco General Hospital (SFGH), Orthopaedic Trauma Institute, 2550 23 Street, Building 9, 3 Floor, San Francisco, CA 94110
| | - Ralph S Marcucio
- University of California, San Francisco (UCSF) & San Francisco General Hospital (SFGH), Orthopaedic Trauma Institute, 2550 23 Street, Building 9, 3 Floor, San Francisco, CA 94110
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