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Griesbach JK, Schulte FA, Schädli GN, Rubert M, Müller R. Mechanoregulation analysis of bone formation in tissue engineered constructs requires a volumetric method using time-lapsed micro-computed tomography. Acta Biomater 2024; 179:149-163. [PMID: 38492908 DOI: 10.1016/j.actbio.2024.03.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Revised: 02/09/2024] [Accepted: 03/07/2024] [Indexed: 03/18/2024]
Abstract
Bone can adapt its microstructure to mechanical loads through mechanoregulation of the (re)modeling process. This process has been investigated in vivo using time-lapsed micro-computed tomography (micro-CT) and micro-finite element (FE) analysis using surface-based methods, which are highly influenced by surface curvature. Consequently, when trying to investigate mechanoregulation in tissue engineered bone constructs, their concave surfaces make the detection of mechanoregulation impossible when using surface-based methods. In this study, we aimed at developing and applying a volumetric method to non-invasively quantify mechanoregulation of bone formation in tissue engineered bone constructs using micro-CT images and FE analysis. We first investigated hydroxyapatite scaffolds seeded with human mesenchymal stem cells that were incubated over 8 weeks with one mechanically loaded and one control group. Higher mechanoregulation of bone formation was measured in loaded samples with an area under the curve for the receiver operating curve (AUCformation) of 0.633-0.637 compared to non-loaded controls (AUCformation: 0.592-0.604) during culture in osteogenic medium (p < 0.05). Furthermore, we applied the method to an in vivo mouse study investigating the effect of loading frequencies on bone adaptation. The volumetric method detected differences in mechanoregulation of bone formation between loading conditions (p < 0.05). Mechanoregulation in bone formation was more pronounced (AUCformation: 0.609-0.642) compared to the surface-based method (AUCformation: 0.565-0.569, p < 0.05). Our results show that mechanoregulation of formation in bone tissue engineered constructs takes place and its extent can be quantified with a volumetric mechanoregulation method using time-lapsed micro-CT and FE analysis. STATEMENT OF SIGNIFICANCE: Many efforts have been directed towards optimizing bone scaffolds for tissue growth. However, the impact of the scaffolds mechanical environment on bone growth is still poorly understood, requiring accurate assessment of its mechanoregulation. Existing surface-based methods were unable to detect mechanoregulation in tissue engineered constructs, due to predominantly concave surfaces in scaffolds. We present a volumetric approach to enable the precise and non-invasive quantification and analysis of mechanoregulation in bone tissue engineered constructs by leveraging time-lapsed micro-CT imaging, image registration, and finite element analysis. The implications of this research extend to diverse experimental setups, encompassing culture conditions, and material optimization, and investigations into bone diseases, enabling a significant stride towards comprehensive advancements in bone tissue engineering and regenerative medicine.
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Affiliation(s)
- Julia K Griesbach
- Institute for Biomechanics, ETH Zürich, Gloriastrasse 37/39, 8092 Zürich, Switzerland
| | - Friederike A Schulte
- Institute for Biomechanics, ETH Zürich, Gloriastrasse 37/39, 8092 Zürich, Switzerland
| | - Gian Nutal Schädli
- Institute for Biomechanics, ETH Zürich, Gloriastrasse 37/39, 8092 Zürich, Switzerland
| | - Marina Rubert
- Institute for Biomechanics, ETH Zürich, Gloriastrasse 37/39, 8092 Zürich, Switzerland
| | - Ralph Müller
- Institute for Biomechanics, ETH Zürich, Gloriastrasse 37/39, 8092 Zürich, Switzerland.
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2
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Ammar A, Koshyk A, Kohut M, Alolabi B, Quenneville CE. The Use of Optical Tracking to Characterize Fracture Gap Motions and Estimate Healing Potential in Comminuted Biomechanical Models of Surgical Repair. Ann Biomed Eng 2023; 51:2258-2266. [PMID: 37294414 DOI: 10.1007/s10439-023-03265-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Accepted: 05/31/2023] [Indexed: 06/10/2023]
Abstract
Fracture healing is stimulated by micromotion at the fracture site, whereby there exists an optimal amount of strain to promote secondary bone formation. Surgical plates used for fracture fixation are often evaluated for their biomechanical performance using benchtop studies, where success is based on overall construct stiffness and strength measures. Integration of fracture gap tracking to this assessment would provide crucial information about how plates support the various fragments present in comminuted fractures, to ensure there are appropriate levels of micromotion during early healing. The goal of this study was to configure an optical tracking system to quantify 3D interfragmentary motion to assess the stability (and corresponding healing potential) of comminuted fractures. An optical tracking system (OptiTrack, Natural Point Inc, Corvallis, OR) was mounted to a material testing machine (Instron 1567, Norwood, MA, USA), with an overall marker tracking accuracy of 0.05 mm. Marker clusters were constructed that could be affixed to individual bone fragments, and segment-fixed coordinate systems were developed. The interfragmentary motion was calculated by tracking the segments while under load and was resolved into compression-extraction and shear components. This technique was evaluated using two cadaveric distal tibia-fibula complexes with simulated intra-articular pilon fractures. Normal and shear strains were tracked during cyclic loading (for stiffness tests), and a wedge gap was also tracked to assess failure in an alternate clinically relevant mode. This technique will augment the utility of benchtop fracture studies by moving beyond total construct response and providing anatomically relevant data on interfragmentary motion, a valuable proxy for healing potential.
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Affiliation(s)
- A Ammar
- School of Biomedical Engineering, McMaster University, Hamilton, ON, Canada
| | - A Koshyk
- Department of Mechanical Engineering, McMaster University, Hamilton, ON, Canada
| | - M Kohut
- School of Biomedical Engineering, McMaster University, Hamilton, ON, Canada
| | - B Alolabi
- Division of Orthopaedic Surgery, Department of Surgery, McMaster University, Hamilton, ON, Canada
| | - C E Quenneville
- School of Biomedical Engineering, McMaster University, Hamilton, ON, Canada.
- Department of Mechanical Engineering, McMaster University, Hamilton, ON, Canada.
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3
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Li R, Cheng W, Liu H, Luo R, Zou H, Zhang L, Ren T, Xu C. Effect of Mechanical Loading on Bone Regeneration in HA/β-TCP/SF Scaffolds Prepared by Low-Temperature 3D Printing In Vivo. ACS Biomater Sci Eng 2023; 9:4980-4993. [PMID: 37428513 DOI: 10.1021/acsbiomaterials.3c00437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/11/2023]
Abstract
It has been well demonstrated that a dynamic culture environment improves tissue-engineered bone formation in vitro, but little is known about how cyclical mechanical loading induced bone formation in scaffolds in situ. To mimic the organic and inorganic components and multilevel structure of a bony microenvironment, hydroxyapatite/β tricalcium phosphate/silk fibroin(HA/β-TCP/SF) composite scaffolds with macro- and micropores were fabricated in this study. The mechanical properties and structure of the scaffolds were adjusted based on the ratio of organic and inorganic components and three-dimensional (3D) printing parameters. Dynamic sinusoidal loading with different frequencies was applied to the composite scaffold. Mouse bone precursor cells MC3T3-E1 were seeded on the scaffolds, and the cell compatibility of the scaffolds was investigated by MTT, SEM, and HE. The effect of the loading on bone formation in the scaffold in situ was investigated in a rabbit tibia defect model. The scaffold showed viscoelasticity and hysteresis under dynamic sinusoidal loading with different frequencies. With an increase in HA/β-TCP, the stress and modulus of the scaffolds increased. MTT, SEM, and HE results showed that MC3T3-E1 cells could adhere and proliferate on the composite scaffolds. After loading in vivo, the quantity of newly formed bone and the bone volume fraction increased. Micro-CT, undecalcified Van Gieson (VG) staining, and fluorescent double-labeling results suggested that appropriate cyclical mechanical loading at frequencies of 1 and 10 Hz had positive effects on bone formation in situ and it may play a role in clinical bone defect repair.
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Affiliation(s)
- Ruixin Li
- Tianjin Key Laboratory of Oral and Maxillofacial Function Reconstruction, Tianjin Stomatological Hospital, The Affiliated Stomatological Hospital of Nankai University, Tianjin 300041, China
| | - Wei Cheng
- People's Hospital of Henan University of Traditional Chinese Medicine, Zhengzhou 450003, China
| | - Hao Liu
- Tianjin Key Laboratory of Oral and Maxillofacial Function Reconstruction, Tianjin Stomatological Hospital, The Affiliated Stomatological Hospital of Nankai University, Tianjin 300041, China
| | - Rui Luo
- Tianjin Key Laboratory of Oral and Maxillofacial Function Reconstruction, Tianjin Stomatological Hospital, The Affiliated Stomatological Hospital of Nankai University, Tianjin 300041, China
| | - Huiru Zou
- Tianjin Key Laboratory of Oral and Maxillofacial Function Reconstruction, Tianjin Stomatological Hospital, The Affiliated Stomatological Hospital of Nankai University, Tianjin 300041, China
| | - Linkun Zhang
- Tianjin Key Laboratory of Oral and Maxillofacial Function Reconstruction, Tianjin Stomatological Hospital, The Affiliated Stomatological Hospital of Nankai University, Tianjin 300041, China
| | - Tingting Ren
- China National Accreditation Service for Conformity Assessment, Beijing 100062, China
| | - Cheng Xu
- Senior Department of Orthopedics, The Fourth Medical Center of PLA General Hospital, Beijing 100048, China
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4
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Kumar R, Pathak VK. Prediction of cortical bone mineral apposition rate in response to loading using an adaptive neuro-fuzzy inference system. Comput Methods Biomech Biomed Engin 2023; 26:261-280. [PMID: 35373664 DOI: 10.1080/10255842.2022.2058322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Daily activities such as aerobic movements and athletic events found effective in mitigating bone loss as it promotes osteogenesis. Computational model considered normal strain, or strain energy density as a stimulus to predict site specific osteogenesis. This model, however, fails to predict site specific osteogenesis as cortical bone surfaces exhibit different remodelling rate to mechanical loading. Remodelling rate or mineral apposition rate depends upon the loading parameters such as loading cycle, frequency, and magnitude of strain. Therefore, the present study aims to develop an adaptive neuro-fuzzy inference system (ANFIS) model for finding a robust relationship between loading parameters like strain magnitude, frequency, and cycle, and a bone remodelling parameter i.e. mineral apposition rate (MAR). The model is trained, tested, and checked with the experimental data. The results indicate that ANFIS model outperformed state of the art Artificial Neural Network (ANN) models during the prediction of MAR at periosteal and endosteal surface. A strong corelation R2 = 0.92 and R2 = 0.97 was observed at 70% of the input data at periosteal and endosteal surface respectively. Result concludes that endosteal surface was more promisable as compared to periosteal surface in predicting accurate MAR. The outcomes of present study may be used to precisely predict site-specific osteogenesis in cortical bone as function of loading parameters.
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Affiliation(s)
- Rakesh Kumar
- Department of Mechanical Engineering, Manipal University Jaipur, Jaipur, India
| | - Vimal Kumar Pathak
- Department of Mechanical Engineering, Manipal University Jaipur, Jaipur, India
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5
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Meslier QA, DiMauro N, Somanchi P, Nano S, Shefelbine SJ. Manipulating load-induced fluid flow in vivo to promote bone adaptation. Bone 2022; 165:116547. [PMID: 36113842 DOI: 10.1016/j.bone.2022.116547] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Revised: 09/01/2022] [Accepted: 09/12/2022] [Indexed: 11/02/2022]
Abstract
Mechanical stimulation is critical to maintaining bone mass and strength. Strain has been commonly thought of as the mechanical stimulus driving bone adaptation. However, numerous studies have hypothesized that fluid flow in the lacunar-canalicular system plays a role in mechanoadaptation. The role of fluid flow compared to strain magnitude on bone remodeling has yet to be characterized. This study aimed to determine the contribution of fluid flow velocity compared to strain on bone adaptation. We used finite element modeling to design in vivo experiments, manipulating strain and fluid flow contributions. Using a uniaxial compression tibia model in mice, we demonstrated that high fluid flow velocity results in significant bone adaptation even under low strain magnitude. In contrast, high strain magnitude paired with low fluid velocity does not trigger a bone response. These findings support previous hypotheses stating that fluid flow is the principal mechanical stimulus driving bone adaptation. Moreover, they give new insights regarding bone adaptative response and provide new pathways toward treatment against age-related mechanosensitivity loss in bone.
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Affiliation(s)
- Quentin A Meslier
- Department of Bioengineering, Northeastern University, Boston, MA, USA
| | - Nicole DiMauro
- Department of Bioengineering, Northeastern University, Boston, MA, USA
| | - Priya Somanchi
- Department of Bioengineering, Northeastern University, Boston, MA, USA
| | - Sarah Nano
- Department of Bioengineering, Northeastern University, Boston, MA, USA
| | - Sandra J Shefelbine
- Department of Bioengineering, Northeastern University, Boston, MA, USA; Department of Mechanical and Industrial Engineering, Northeastern University, Boston, MA, USA.
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6
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Nix Z, Kota D, Ratnayake I, Wang C, Smith S, Wood S. Spectral characterization of cell surface motion for mechanistic investigations of cellular mechanobiology. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2022; 176:3-15. [PMID: 36108781 DOI: 10.1016/j.pbiomolbio.2022.08.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 07/27/2022] [Accepted: 08/05/2022] [Indexed: 06/15/2023]
Abstract
Understanding the specific mechanisms responsible for anabolic and catabolic responses to static or dynamic force are largely poorly understood. Because of this, most research groups studying mechanotransduction due to dynamic forces employ an empirical approach in deciding what frequencies to apply during experiments. While this has been shown to elucidate valuable information regarding how cells respond under controlled provocation, it is often difficult or impossible to determine a true optimal frequency for force application, as many intracellular complexes are involved in receiving, propagating, and responding to a given stimulus. Here we present a novel adaptation of an analytical technique from the fields of civil and mechanical engineering that may open the door to direct measurement of mechanobiological cellular frequencies which could be used to target specific cell signaling pathways leveraging synergy between outside-in and inside-out mechanotransduction approaches. This information could be useful in identifying how specific proteins are involved in the homeostatic balance, or disruption thereof, of cells and tissue, furthering the understanding of the pathogenesis and progression of many diseases across a wide variety of cell types, which may one day lead to the development of novel mechanobiological therapies for clinical use.
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Affiliation(s)
- Zachary Nix
- Department of Nanoscience & Biomedical Engineering, BioSystems Networks / Translational Research (BioSNTR), South Dakota School of Mines and Technology, USA
| | - Divya Kota
- Department of Nanoscience & Biomedical Engineering, BioSystems Networks / Translational Research (BioSNTR), South Dakota School of Mines and Technology, USA
| | - Ishara Ratnayake
- Department of Nanoscience & Biomedical Engineering, BioSystems Networks / Translational Research (BioSNTR), South Dakota School of Mines and Technology, USA
| | - Congzhou Wang
- Department of Nanoscience & Biomedical Engineering, BioSystems Networks / Translational Research (BioSNTR), South Dakota School of Mines and Technology, USA
| | - Steve Smith
- Department of Nanoscience & Biomedical Engineering, BioSystems Networks / Translational Research (BioSNTR), South Dakota School of Mines and Technology, USA
| | - Scott Wood
- Department of Nanoscience & Biomedical Engineering, BioSystems Networks / Translational Research (BioSNTR), South Dakota School of Mines and Technology, USA.
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7
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Smotrova E, Li S, Silberschmidt VV. Mechanoregulated trabecular bone adaptation: Progress report on in silico approaches. BIOMATERIALS AND BIOSYSTEMS 2022; 7:100058. [PMID: 36824485 PMCID: PMC9934474 DOI: 10.1016/j.bbiosy.2022.100058] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 06/28/2022] [Accepted: 07/14/2022] [Indexed: 10/17/2022] Open
Abstract
Adaptation is the process by which bone responds to changes in loading environment and modulates its properties and spatial organization to meet the mechanical demands. Adaptation in trabecular bone is achieved through increase in bone mass and alignment of trabecular-bone morphology along the loading direction. This transformation of internal microstructure is governed by mechanical stimuli sensed by mechanosensory cells in the bone matrix. Realisation of adaptation in the form of local bone-resorption and -formation activities as a function of mechanical stimuli is still debated. In silico modelling is a useful tool for simulation of various scenarios that cannot be investigated in vivo and particularly well suited for prediction of trabecular bone adaptation. This progress report presents the recent advances in in silico modelling of mechanoregulated adaptation at the scale of trabecular bone tissue. Four well-established bone-adaptation models are reviewed in terms of their recent improvements and validation. They consider various mechanical factors: (i) strain energy density, (ii) strain and damage, (iii) stress nonuniformity and (iv) daily stress. Contradictions of these models are discussed and their ability to describe adequately a real-life mechanoregulation process in bone is compared.
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8
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Lutek K, Donatelli CM, Standen EM. Patterns and processes in amphibious fish: biomechanics and neural control of fish terrestrial locomotion. J Exp Biol 2022; 225:275243. [PMID: 35502693 DOI: 10.1242/jeb.242395] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Amphibiousness in fishes spans the actinopterygian tree from the earliest to the most recently derived species. The land environment requires locomotor force production different from that in water, and a diversity of locomotor modes have evolved across the actinopterygian tree. To compare locomotor mode between species, we mapped biomechanical traits on an established amphibious fish phylogeny. Although the diversity of fish that can move over land is large, we noted several patterns, including the rarity of morphological and locomotor specialization, correlations between body shape and locomotor mode, and an overall tendency for amphibious fish to be small. We suggest two idealized empirical metrics to consider when gauging terrestrial 'success' in fishes and discuss patterns of terrestriality in fishes considering biomechanical scaling, physical consequences of shape, and tissue plasticity. Finally, we suggest four ways in which neural control could change in response to a novel environment, highlighting the importance and challenges of deciphering when these control mechanisms are used. We aim to provide an overview of the diversity of successful amphibious locomotion strategies and suggest several frameworks that can guide the study of amphibious fish and their locomotion.
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Affiliation(s)
- K Lutek
- Department of Biology, University of Ottawa, Ottawa, Canada, K1N 6N5
| | - C M Donatelli
- Department of Biology, University of Ottawa, Ottawa, Canada, K1N 6N5
| | - E M Standen
- Department of Biology, University of Ottawa, Ottawa, Canada, K1N 6N5
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9
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Zhang C, Farré-Guasch E, Jin J, van Essen HW, Klein-Nulend J, Bravenboer N. A Three-Dimensional Mechanical Loading Model of Human Osteocytes in Their Native Matrix. Calcif Tissue Int 2022; 110:367-379. [PMID: 34647170 PMCID: PMC8860829 DOI: 10.1007/s00223-021-00919-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Accepted: 09/20/2021] [Indexed: 11/30/2022]
Abstract
Osteocytes are mechanosensory cells which are embedded in calcified collagenous matrix. The specific native matrix of osteocytes affects their regulatory activity, i.e., transmission of signaling molecules to osteoclasts and/or osteoblasts, in the mechanical adaptation of bone. Unfortunately, no existing in vitro model of cortical bone is currently available to study the mechanosensory function of human osteocytes in their native matrix. Therefore, we aimed to develop an in vitro three-dimensional mechanical loading model of human osteocytes in their native matrix. Human cortical bone explants containing osteocytes in their three-dimensional native matrix were cultured and mechanically loaded by three-point bending using a custom-made loading apparatus generating sinusoidal displacement. Osteocyte viability and sclerostin expression were measured 1-2 days before 5 min loading and 1 day after loading. Bone microdamage was visualized and quantified by micro-CT analysis and histology using BaSO4 staining. A linear relationship was found between loading magnitude (2302-13,811 µɛ) and force (1.6-4.9 N) exerted on the bone explants. At 24 h post-loading, osteocyte viability was not affected by 1600 µɛ loading. Sclerostin expression and bone microdamage were unaffected by loading up to 8000 µɛ. In conclusion, we developed an in vitro 3D mechanical loading model to study mechanoresponsiveness of viable osteocytes residing in their native matrix. This model is suitable to study the effect of changed bone matrix composition in metabolic bone disease on osteocyte mechanoresponsiveness.
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Affiliation(s)
- Chen Zhang
- Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Amsterdam, The Netherlands
- Department of Clinical Chemistry, Amsterdam University Medical Centers, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, P.O. Box 7057, 1007 MB, Amsterdam, The Netherlands
| | - Elisabet Farré-Guasch
- Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Amsterdam, The Netherlands
| | - Jianfeng Jin
- Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Amsterdam, The Netherlands
| | - Huib W van Essen
- Department of Clinical Chemistry, Amsterdam University Medical Centers, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, P.O. Box 7057, 1007 MB, Amsterdam, The Netherlands
| | - Jenneke Klein-Nulend
- Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Amsterdam, The Netherlands
| | - Nathalie Bravenboer
- Department of Clinical Chemistry, Amsterdam University Medical Centers, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, P.O. Box 7057, 1007 MB, Amsterdam, The Netherlands.
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10
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Gao Y, Lu F, Wang S, Sun L, Leng H, Huo B. Effect of long-term cyclic compression loading on the structural evolution of trabecular bone. MEDICINE IN NOVEL TECHNOLOGY AND DEVICES 2021. [DOI: 10.1016/j.medntd.2021.100099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
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11
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Malhotra A, Walle M, Paul GR, Kuhn GA, Müller R. Application of subject-specific adaptive mechanical loading for bone healing in a mouse tail vertebral defect. Sci Rep 2021; 11:1861. [PMID: 33479260 PMCID: PMC7820598 DOI: 10.1038/s41598-021-81132-8] [Citation(s) in RCA: 129] [Impact Index Per Article: 43.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Accepted: 01/04/2021] [Indexed: 12/13/2022] Open
Abstract
Methods to repair bone defects arising from trauma, resection, or disease, continue to be sought after. Cyclic mechanical loading is well established to influence bone (re)modelling activity, in which bone formation and resorption are correlated to micro-scale strain. Based on this, the application of mechanical stimulation across a bone defect could improve healing. However, if ignoring the mechanical integrity of defected bone, loading regimes have a high potential to either cause damage or be ineffective. This study explores real-time finite element (rtFE) methods that use three-dimensional structural analyses from micro-computed tomography images to estimate effective peak cyclic loads in a subject-specific and time-dependent manner. It demonstrates the concept in a cyclically loaded mouse caudal vertebral bone defect model. Using rtFE analysis combined with adaptive mechanical loading, mouse bone healing was significantly improved over non-loaded controls, with no incidence of vertebral fractures. Such rtFE-driven adaptive loading regimes demonstrated here could be relevant to clinical bone defect healing scenarios, where mechanical loading can become patient-specific and more efficacious. This is achieved by accounting for initial bone defect conditions and spatio-temporal healing, both being factors that are always unique to the patient.
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Affiliation(s)
- Angad Malhotra
- Institute for Biomechanics, ETH Zurich, Leopold-Ruzicka-Weg 4, 8093, Zurich, Switzerland
| | - Matthias Walle
- Institute for Biomechanics, ETH Zurich, Leopold-Ruzicka-Weg 4, 8093, Zurich, Switzerland
| | - Graeme R Paul
- Institute for Biomechanics, ETH Zurich, Leopold-Ruzicka-Weg 4, 8093, Zurich, Switzerland
| | - Gisela A Kuhn
- Institute for Biomechanics, ETH Zurich, Leopold-Ruzicka-Weg 4, 8093, Zurich, Switzerland
| | - Ralph Müller
- Institute for Biomechanics, ETH Zurich, Leopold-Ruzicka-Weg 4, 8093, Zurich, Switzerland.
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12
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Scheuren AC, Vallaster P, Kuhn GA, Paul GR, Malhotra A, Kameo Y, Müller R. Mechano-Regulation of Trabecular Bone Adaptation Is Controlled by the Local in vivo Environment and Logarithmically Dependent on Loading Frequency. Front Bioeng Biotechnol 2020; 8:566346. [PMID: 33154964 PMCID: PMC7591723 DOI: 10.3389/fbioe.2020.566346] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 09/23/2020] [Indexed: 12/23/2022] Open
Abstract
It is well-established that cyclic, but not static, mechanical loading has anabolic effects on bone. However, the function describing the relationship between the loading frequency and the amount of bone adaptation remains unclear. Using a combined experimental and computational approach, this study aimed to investigate whether trabecular bone mechano-regulation is controlled by mechanical signals in the local in vivo environment and dependent on loading frequency. Specifically, by combining in vivo micro-computed tomography (micro-CT) imaging with micro-finite element (micro-FE) analysis, we monitored the changes in microstructural as well as the mechanical in vivo environment [strain energy density (SED) and SED gradient] of mouse caudal vertebrae over 4 weeks of either cyclic loading at varying frequencies of 2, 5, or 10 Hz, respectively, or static loading. Higher values of SED and SED gradient on the local tissue level led to an increased probability of trabecular bone formation and a decreased probability of trabecular bone resorption. In all loading groups, the SED gradient was superior in the determination of local bone formation and resorption events as compared to SED. Cyclic loading induced positive net (re)modeling rates when compared to sham and static loading, mainly due to an increase in mineralizing surface and a decrease in eroded surface. Consequently, bone volume fraction increased over time in 2, 5, and 10 Hz (+15%, +21% and +24%, p ≤ 0.0001), while static loading led to a decrease in bone volume fraction (-9%, p ≤ 0.001). Furthermore, regression analysis revealed a logarithmic relationship between loading frequency and the net change in bone volume fraction over the 4 week observation period (R 2 = 0.74). In conclusion, these results suggest that trabecular bone adaptation is regulated by mechanical signals in the local in vivo environment and furthermore, that mechano-regulation is logarithmically dependent on loading frequency with frequencies below a certain threshold having catabolic effects, and those above anabolic effects. This study thereby provides valuable insights toward a better understanding of the mechanical signals influencing trabecular bone formation and resorption in the local in vivo environment.
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Affiliation(s)
| | - Paul Vallaster
- Institute for Biomechanics, ETH Zurich, Zurich, Switzerland
| | - Gisela A. Kuhn
- Institute for Biomechanics, ETH Zurich, Zurich, Switzerland
| | - Graeme R. Paul
- Institute for Biomechanics, ETH Zurich, Zurich, Switzerland
| | - Angad Malhotra
- Institute for Biomechanics, ETH Zurich, Zurich, Switzerland
| | - Yoshitaka Kameo
- Institute for Biomechanics, ETH Zurich, Zurich, Switzerland
- Institute for Frontier Life and Medical Sciences, Kyoto University, Kyoto, Japan
| | - Ralph Müller
- Institute for Biomechanics, ETH Zurich, Zurich, Switzerland
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13
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Du TY, Standen EM. Terrestrial acclimation and exercise lead to bone functional response in Polypterus senegalus pectoral fins. J Exp Biol 2020; 223:jeb217554. [PMID: 32414872 DOI: 10.1242/jeb.217554] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Accepted: 04/25/2020] [Indexed: 11/20/2022]
Abstract
The ability of bones to sense and respond to mechanical loading is a central feature of vertebrate skeletons. However, the functional demands imposed on terrestrial and aquatic animals differ vastly. The pectoral girdle of the basal actinopterygian fish Polypterus senegalus was previously shown to exhibit plasticity following terrestrial acclimation, but the pectoral fin itself has yet to be examined. We investigated skeletal plasticity in the pectoral fins of P. senegalus after exposure to terrestrial loading. Juvenile fish were divided into three groups: a control group was kept under aquatic conditions without intervention, an exercised group was also kept in water but received daily exercise on land, and a terrestrial group was kept in a chronic semi-terrestrial condition. After 5 weeks, the pectoral fins were cleared and stained with Alcian Blue and Alizarin Red to visualize cartilage and bone, allowing measurements of bone length, bone width, ossification and curvature to be taken for the endochondral radial bones. Polypterus senegalus fin bones responded most strongly to chronic loading in the terrestrial condition. Fish that were reared in a terrestrial environment had significantly longer bones compared with those of aquatic controls, wider propterygia and metapterygia, and more ossified metapterygia and medial radials, and they showed changes in propterygial curvature. Exercised fish also had longer and more ossified medial radials compared with those of controls. Polypterus senegalus fin bones exhibit plasticity in response to novel terrestrial loading. Such plasticity could be relevant for transitions between water and land on evolutionary scales, but key differences between fish and tetrapod bone make direct comparisons challenging.
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Affiliation(s)
- Trina Y Du
- Department of Biology, University of Ottawa, Gendron Hall, 30 Marie Curie, Ottawa, ON, Canada K1N 6N5
| | - Emily M Standen
- Department of Biology, University of Ottawa, Gendron Hall, 30 Marie Curie, Ottawa, ON, Canada K1N 6N5
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Griffith CM, Huang SA, Cho C, Khare TM, Rich M, Lee GH, Ligler FS, Diekman BO, Polacheck WJ. Microfluidics for the study of mechanotransduction. JOURNAL OF PHYSICS D: APPLIED PHYSICS 2020; 53:224004. [PMID: 33840837 PMCID: PMC8034607 DOI: 10.1088/1361-6463/ab78d4] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Mechanical forces regulate a diverse set of biological processes at cellular, tissue, and organismal length scales. Investigating the cellular and molecular mechanisms that underlie the conversion of mechanical forces to biological responses is challenged by limitations of traditional animal models and in vitro cell culture, including poor control over applied force and highly artificial cell culture environments. Recent advances in fabrication methods and material processing have enabled the development of microfluidic platforms that provide precise control over the mechanical microenvironment of cultured cells. These devices and systems have proven to be powerful for uncovering and defining mechanisms of mechanotransduction. In this review, we first give an overview of the main mechanotransduction pathways that function at sites of cell adhesion, many of which have been investigated with microfluidics. We then discuss how distinct microfluidic fabrication methods can be harnessed to gain biological insight, with description of both monolithic and replica molding approaches. Finally, we present examples of how microfluidics can be used to apply both solid forces (substrate mechanics, strain, and compression) and fluid forces (luminal, interstitial) to cells. Throughout the review, we emphasize the advantages and disadvantages of different fabrication methods and applications of force in order to provide perspective to investigators looking to apply forces to cells in their own research.
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Affiliation(s)
- Christian M Griffith
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill, Chapel Hill, NC and North Carolina State University, Raleigh, NC
| | - Stephanie A Huang
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill, Chapel Hill, NC and North Carolina State University, Raleigh, NC
| | - Crescentia Cho
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill, Chapel Hill, NC and North Carolina State University, Raleigh, NC
| | - Tanmay M Khare
- Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, NC
| | - Matthew Rich
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill, Chapel Hill, NC and North Carolina State University, Raleigh, NC
- Thurston Arthritis Research Center, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC
| | - Gi-Hun Lee
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill, Chapel Hill, NC and North Carolina State University, Raleigh, NC
| | - Frances S Ligler
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill, Chapel Hill, NC and North Carolina State University, Raleigh, NC
| | - Brian O Diekman
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill, Chapel Hill, NC and North Carolina State University, Raleigh, NC
- Thurston Arthritis Research Center, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC
| | - William J Polacheck
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill, Chapel Hill, NC and North Carolina State University, Raleigh, NC
- McAllister Heart Institute, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC
- Cancer Cell Biology Program, Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC
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15
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Main RP, Shefelbine SJ, Meakin LB, Silva MJ, van der Meulen MC, Willie BM. Murine Axial Compression Tibial Loading Model to Study Bone Mechanobiology: Implementing the Model and Reporting Results. J Orthop Res 2020; 38:233-252. [PMID: 31508836 PMCID: PMC9344861 DOI: 10.1002/jor.24466] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Accepted: 08/23/2019] [Indexed: 02/04/2023]
Abstract
In vivo, tibial loading in mice is increasingly used to study bone adaptation and mechanotransduction. To achieve standardized and defined experimental conditions, loading parameters and animal-related factors must be considered when performing in vivo loading studies. In this review, we discuss these loading and animal-related experimental conditions, present methods to assess bone adaptation, and suggest reporting guidelines. This review originated from presentations by each of the authors at the workshop "Developing Best Practices for Mouse Models of In Vivo Loading" during the Preclinical Models Section at the Orthopaedic Research Society Annual Meeting, San Diego, CA, March 2017. Following the meeting, the authors engaged in detailed discussions with consideration of relevant literature. The guidelines and recommendations in this review are provided to help researchers perform in vivo loading experiments in mice, and thus further our knowledge of bone adaptation and the mechanisms involved in mechanotransduction. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:233-252, 2020.
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Affiliation(s)
- Russell P. Main
- Department of Basic Medical Sciences and Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA,Corresponding author: Russell Main ()
| | - Sandra J. Shefelbine
- Department of Bioengineering, Department of Mechanical and Industrial Engineering, Northeastern University, Boston, MA, USA
| | - Lee B. Meakin
- Bristol Veterinary School, University of Bristol, Langford, Bristol BS40 5DU, UK
| | - Matthew J. Silva
- Departments of Orthopaedic Surgery and Biomedical Engineering, Musculoskeletal Research Center, Washington University, Saint Louis, MO, USA
| | - Marjolein C.H van der Meulen
- Meinig School of Biomedical Engineering and Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, NY, USA
| | - Bettina M. Willie
- Research Centre, Shriners Hospital for Children-Canada, Department of Pediatric Surgery, McGill University, Montreal, Canada
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16
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Canalicular fluid flow induced by loading waveforms: A comparative analysis. J Theor Biol 2019; 471:59-73. [DOI: 10.1016/j.jtbi.2019.03.023] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Revised: 03/25/2019] [Accepted: 03/28/2019] [Indexed: 12/17/2022]
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17
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Hemmatian H, Jalali R, Semeins CM, Hogervorst JMA, van Lenthe GH, Klein-Nulend J, Bakker AD. Mechanical Loading Differentially Affects Osteocytes in Fibulae from Lactating Mice Compared to Osteocytes in Virgin Mice: Possible Role for Lacuna Size. Calcif Tissue Int 2018; 103:675-685. [PMID: 30109376 PMCID: PMC6208961 DOI: 10.1007/s00223-018-0463-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Accepted: 07/30/2018] [Indexed: 12/31/2022]
Abstract
Hormonal changes during lactation are associated with profound changes in bone cell biology, such as osteocytic osteolysis, resulting in larger lacunae. Larger lacuna shape theoretically enhances the transmission of mechanical signals to osteocytes. We aimed to provide experimental evidence supporting this theory by comparing the mechanoresponse of osteocytes in the bone of lactating mice, which have enlarged lacunae due to osteocytic osteolysis, with the response of osteocytes in bone from age-matched virgin mice. The osteocyte mechanoresponse was measured in excised fibulae that were cultured in hormone-free medium for 24 h and cyclically loaded for 10 min (sinusoidal compressive load, 3000 µε, 5 Hz) by quantifying loading-related changes in Sost mRNA expression (qPCR) and sclerostin and β-catenin protein expression (immunohistochemistry). Loading decreased Sost expression by ~ threefold in fibulae of lactating mice. The loading-induced decrease in sclerostin protein expression by osteocytes was larger in lactating mice (55% decrease ± 14 (± SD), n = 8) than virgin mice (33% decrease ± 15, n = 7). Mechanical loading upregulated β-catenin expression in osteocytes in lactating mice by 3.5-fold (± 0.2, n = 6) which is significantly (p < 0.01) higher than the 1.6-fold increase in β-catenin expression by osteocytes in fibulae from virgin mice (± 0.12, n = 4). These results suggest that osteocytes in fibulae from lactating mice with large lacunae may respond stronger to mechanical loading than those from virgin mice. This could indicate that osteocytes residing in larger lacuna show a stronger response to mechanical loading.
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Affiliation(s)
- Haniyeh Hemmatian
- Biomechanics Section, Department of Mechanical Engineering, KU Leuven, Leuven, Belgium
- Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Gustav Mahlerlaan 3004, 1081 LA, Amsterdam, The Netherlands
| | - Rozita Jalali
- Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Gustav Mahlerlaan 3004, 1081 LA, Amsterdam, The Netherlands
| | - Cornelis M Semeins
- Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Gustav Mahlerlaan 3004, 1081 LA, Amsterdam, The Netherlands
| | - Jolanda M A Hogervorst
- Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Gustav Mahlerlaan 3004, 1081 LA, Amsterdam, The Netherlands
| | - G Harry van Lenthe
- Biomechanics Section, Department of Mechanical Engineering, KU Leuven, Leuven, Belgium
| | - Jenneke Klein-Nulend
- Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Gustav Mahlerlaan 3004, 1081 LA, Amsterdam, The Netherlands.
| | - Astrid D Bakker
- Department of Oral Cell Biology, Academic Centre for Dentistry Amsterdam (ACTA), University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Gustav Mahlerlaan 3004, 1081 LA, Amsterdam, The Netherlands
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Kersh ME, Martelli S, Zebaze R, Seeman E, Pandy MG. Mechanical Loading of the Femoral Neck in Human Locomotion. J Bone Miner Res 2018; 33:1999-2006. [PMID: 29920773 DOI: 10.1002/jbmr.3529] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Revised: 05/30/2018] [Accepted: 06/12/2018] [Indexed: 11/08/2022]
Abstract
Advancing age and reduced loading are associated with a reduction in bone formation. Conversely, loading increases periosteal apposition and may reduce remodeling imbalance and slow age-related bone loss, an important outcome for the proximal femur, which is a common site of fracture. The ability to take advantage of bone's adaptive response to increase bone strength has been hampered by a lack of knowledge of which exercises and specific leg muscles load the superior femoral neck: a common region of microcrack initiation and progression following a sideways fall. We used an in vivo method of quantifying focal strains within the femoral neck in postmenopausal women during walking, stair ambulation, and jumping. Relative to walking, stair ambulation and jumping induced significantly higher strains in the anterior and superior aspects of the femoral neck, common regions of microcrack initiation and progression following a fall. The gluteus maximus, a hip extensor muscle, induced strains in the femoral neck during stair ambulation and jumping, in contrast to walking which induced strains via the iliopsoas, a hip flexor. The ground reaction force was closely associated with the level of strain during each task, providing a surrogate indicator of the potential for a given exercise to load the femoral neck. The gluteal muscles combined with an increased ground reaction force relative to walking induce high focal strains within the anterosuperior region of the femoral neck and therefore provide a target for exercise regimens designed to slow bone loss and maintain or improve microstructural strength. Model files used for calculating femoral neck strains are available at uitbl.mechse.illinois.edu/downloads © 2018 American Society for Bone and Mineral Research.
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Affiliation(s)
- Mariana E Kersh
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Saulo Martelli
- Medical Device Research Institute, College of Science and Engineering Flinders University, Tonsley, SA, Australia
| | - Roger Zebaze
- Departments of Medicine and Endocrinology, Austin Health, University of Melbourne, Heidelberg West, VIC, Australia
| | - Ego Seeman
- Departments of Medicine and Endocrinology, Austin Health, University of Melbourne, Heidelberg West, VIC, Australia.,Mary Mackillop Institute for Health Research, Australian Catholic University, Fitzroy, VIC, Australia
| | - Marcus G Pandy
- Department of Mechanical Engineering, University of Melbourne, Parkville, VIC, Australia
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19
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Mechanical, material, and biological study of a PCL/bioactive glass bone scaffold: Importance of viscoelasticity. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2018; 90:280-288. [DOI: 10.1016/j.msec.2018.04.080] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Revised: 03/18/2018] [Accepted: 04/25/2018] [Indexed: 12/13/2022]
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20
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Ostadi Moghaddam A, Mahjoob M, Nazarian A. Bone Remodeling under Vibration: A Computational Model of Bone Remodeling Incorporating the Modal Behavior of Bone. J Biomech Eng 2018; 140:2686529. [PMID: 30029231 DOI: 10.1115/1.4040602] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Indexed: 11/08/2022]
Abstract
Developing precise computational models of bone remodeling can lead to more successful types of orthopedic treatments and deeper understanding of the phenomenon. Empirical evidence has shown that bone adaptation to mechanical loading is frequency dependent and the modal behavior of bone under vibration can play a significant role in remodeling process, particularly in the resonance region. The objective of this study is to develop a bone remodeling algorithm that takes into account the effects of bone vibrational behavior. An extended/modified model is presented based on conventional FE remodeling models. Frequency domain analysis is used to introduce appropriate correction coefficients to incorporate the effect of bone's frequency response into the model. The method is implemented on a bovine bone with known modal/vibration characteristics. The rate and locations of new bone formation depend on the loading frequency and are consistently correlated with the bone modal behavior. The proposed method can successfully integrate the bone vibration conditions and characteristics with the remodeling process. The results obtained support experimental observations in the literature.
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Affiliation(s)
- Amir Ostadi Moghaddam
- School of Mechanical Eng., College of Engineering Kargar St. North, Jalal Ale Ahmad Intersection Tehran, Tehran 11155-4563 Islamic Republic Of Iran
| | - Mohammad Mahjoob
- School of Mechanical Engineering, College of Engineering, University of Tehran, Tehran, Iran; Center for Advance Orthopedic Studies, BID Medical Center, Harvard Medical School, Boston, MA, USA
| | - Ara Nazarian
- Center for Advance Orthopedic Studies, BID Medical Center, Harvard Medical School, Boston, MA, USA
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21
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Reina-Romo E, Rodríguez-Vallés J, Sanz-Herrera JA. In silico dynamic characterization of the femur: Physiological versus mechanical boundary conditions. Med Eng Phys 2018; 58:S1350-4533(18)30090-0. [PMID: 29945761 DOI: 10.1016/j.medengphy.2018.06.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Revised: 05/30/2018] [Accepted: 06/07/2018] [Indexed: 02/06/2023]
Abstract
It is established that bone tissue adapts and responds to mechanical loading. Several studies have suggested an existence of positive influence of vibration on the bone mass maintenance. Thus, some bone regeneration therapies are based on vibration of bone tissue under circumstances of disease to stimulate its formation. Frequency of loading should be properly selected and therefore a correct characterization of the dynamic properties of this tissue may be critical for the success of such orthopedic techniques. On the other hand, many studies implement vibration techniques with in silico models. Numerical results are exclusively dependent on properties of bone tissue, i.e. geometry, density distribution and stiffness, as well as boundary conditions. In the present study, the influence of boundary conditions and material properties on the dynamic characteristics of bone tissue was explored in a human femur. Bone shape and density were directly reconstructed from computer tomographies, whereas natural frequencies and modes of vibration were obtained for different boundary conditions including physiological and mechanical ones. Results of this study show the moderate effect of material properties compared to the much substantial effect of boundary conditions. A factor of 2 in the natural frequency was obtained depending on imposed boundary conditions, highlighting the importance in the selection of appropriate conditions in the analysis of the bone organ.
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Affiliation(s)
- E Reina-Romo
- School of Engineering, University of Seville, 41092 Seville, Spain
| | | | - J A Sanz-Herrera
- School of Engineering, University of Seville, 41092 Seville, Spain.
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22
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Tiwari AK, Kumar N. Establishing the relationship between loading parameters and bone adaptation. Med Eng Phys 2018; 56:16-26. [DOI: 10.1016/j.medengphy.2018.04.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Revised: 03/28/2018] [Accepted: 04/10/2018] [Indexed: 10/17/2022]
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23
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Cresswell EN, McDonough SP, Palmer SE, Hernandez CJ, Reesink HL. Can quantitative computed tomography detect bone morphological changes associated with catastrophic proximal sesamoid bone fracture in Thoroughbred racehorses? Equine Vet J 2018; 51:123-130. [DOI: 10.1111/evj.12965] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Accepted: 05/04/2018] [Indexed: 11/29/2022]
Affiliation(s)
| | - S. P. McDonough
- Biomedical Sciences; Cornell University; Ithaca New York USA
| | - S. E. Palmer
- Population Medicine and Diagnostic Sciences; Cornell University; Ithaca New York USA
| | - C. J. Hernandez
- Mechanical and Aerospace Engineering; Cornell University; Ithaca New York USA
| | - H. L. Reesink
- Clinical Sciences; Cornell University; Ithaca New York USA
- Equine and Farm Animal Hospital; Cornell University; Ithaca New York USA
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24
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Armada L, de Castro Brasil S, Armada-Dias L, Bezerra J, Pereira RMR, Takayama L, Moreira Morais Dos Santos R, Gonçalves LS, Nascimento-Saba CCA. Effects of aging, gender, and hypogonadism on mandibular bone density. ACTA ACUST UNITED AC 2018; 9:e12310. [PMID: 29292596 DOI: 10.1111/jicd.12310] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Accepted: 09/27/2017] [Indexed: 11/30/2022]
Abstract
AIM The aim of the present study was to evaluate how aging, sex, and hypogonadism influence mandibular bone density with and without the benefits of hormone treatment. METHODS Three-month old Wistar rats were randomly assigned to three experimental groups, with eights animals per group: controls, castrated (orchiectomized [ORX], ovariectomized [OVX]) and castrated with hormonal treatment (ORX + testosterone, OVX + estradiol benzoate). Females were previously evaluated by vaginal cytology. The corporal mass was verified weekly, and after three experimental periods (90, 120, and 150 days), the animals were killed. Blood was collected, and bones underwent densitometric and biomechanical analyses. RESULTS After castration, the male rats demonstrated low gain in body weight compared to females (P < .05). Male and female castrated animals presented serum concentrations of sex steroid hormones lower than the control group (P < .05). Bone mineral density and biomechanical properties of the L4 vertebrae and femur were reduced earlier in females than in males (P < .05). However, mandibles were affected only in the male rats at the most chronic experimental period. CONCLUSION Hypogonadism promotes alterations in the mandible over chronic periods, especially in males, and these alterations could be minimized by hormone treatment.
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Affiliation(s)
- Luciana Armada
- Department of Endodontics, Faculty of Dentistry, Estácio de Sá University, Rio de Janeiro, Brazil
| | - Sabrina de Castro Brasil
- Department of Endodontics, Faculty of Dentistry, Estácio de Sá University, Rio de Janeiro, Brazil
| | - Luci Armada-Dias
- Department of Endodontics, Faculty of Dentistry, Estácio de Sá University, Rio de Janeiro, Brazil
| | - Juciléia Bezerra
- Department of Physiological Sciences, Federal University of São Carlos, São Carlos, Brazil
| | - Rosa M R Pereira
- Bone Metabolism Laboratory of Rheumatology, Faculty of Medicine, University of São Paulo, São Paulo, Brazil
| | - Lilian Takayama
- Bone Metabolism Laboratory of Rheumatology, Faculty of Medicine, University of São Paulo, São Paulo, Brazil
| | | | - Lucio S Gonçalves
- Department of Endodontics, Faculty of Dentistry, Estácio de Sá University, Rio de Janeiro, Brazil
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Huang G, Liu G, Zhang F, Gao J, Wang J, Chen Q, Wu B, Ding Z, Cai T. Combination of Heel-strike like Mechanical Loading with Deproteinized Cancellous Bone Scaffold Implantation to Repair Segmental Bone Defects in Rabbits. Int J Med Sci 2017; 14:871-879. [PMID: 28824324 PMCID: PMC5562194 DOI: 10.7150/ijms.19613] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2017] [Accepted: 05/17/2017] [Indexed: 01/08/2023] Open
Abstract
Under physiological conditions bone defects often occur at mechanical load bearing sites and bone substitutes used for regeneration should be similarly subjected to mechanical loading stress. In this study, we investigated whether a novel heel-strike like mechanical loading method can be used as a complementary therapy to promote bone regeneration following bone substitute grafting. To test this, three groups of rabbits with segmental bone defects in the tibia were implanted with bovine deproteinized cancellous bone scaffold (DCBS), with one group also receiving heel-strike like mechanical loading generated by a rap stress stimulator. From weeks 4-12 post-operation X-ray and micro-CT scanning showed that rabbits receiving combination therapy had significantly more callus at the bone defect. Moreover, bone defects in the combination group were completely replaced with new bone at week 12, while the DCBS implantation alone group healed only partially and rabbits receiving neither DCBS nor mechanical loading developed only small calluses throughout the observation period. Analysis of micro-CT scanning results demonstrated that new bone density in the combination group was significantly higher than the DCBS only group at weeks 4 and 12 (p<0.05). H&E staining results also indicated a significantly higher percentage of new bone in the bone defect area and a lower percentage of residual scaffold in the combination group compared to the DCBS only group (p<0.05). Thus, this heel-strike like mechanical loading method appears to accelerate bone regeneration following substitute implantation by restoring a local mechanical loading environment in segmental bone defects.
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Affiliation(s)
- Guofeng Huang
- Center for Orthopedics, Affiliated Southeast Hospital of Xiamen University/175th Hospital of People's Liberation Army, Zhangzhou, P. R. China, 363000
| | - Guojun Liu
- Center for Orthopedics, Affiliated Southeast Hospital of Xiamen University/175th Hospital of People's Liberation Army, Zhangzhou, P. R. China, 363000
| | - Feng Zhang
- Center for Orthopedics, Affiliated Southeast Hospital of Xiamen University/175th Hospital of People's Liberation Army, Zhangzhou, P. R. China, 363000
| | - Jianting Gao
- Center for Orthopedics, Affiliated Southeast Hospital of Xiamen University/175th Hospital of People's Liberation Army, Zhangzhou, P. R. China, 363000
| | - Jiangze Wang
- Center for Orthopedics, Affiliated Southeast Hospital of Xiamen University/175th Hospital of People's Liberation Army, Zhangzhou, P. R. China, 363000
| | - Qi Chen
- Center for Orthopedics, Affiliated Southeast Hospital of Xiamen University/175th Hospital of People's Liberation Army, Zhangzhou, P. R. China, 363000
| | - Benwen Wu
- Center for Orthopedics, Affiliated Southeast Hospital of Xiamen University/175th Hospital of People's Liberation Army, Zhangzhou, P. R. China, 363000
| | - Zhenqi Ding
- Center for Orthopedics, Affiliated Southeast Hospital of Xiamen University/175th Hospital of People's Liberation Army, Zhangzhou, P. R. China, 363000
| | - Taoyi Cai
- Center for Orthopedics, Affiliated Southeast Hospital of Xiamen University/175th Hospital of People's Liberation Army, Zhangzhou, P. R. China, 363000
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Grünheid T, Langenbach GEJ, Zentner A, Van Eijden TMGJ. Duty Time of Rabbit Jaw Muscles Varies with the Number of Activity Bursts. J Dent Res 2016; 85:1112-7. [PMID: 17122164 DOI: 10.1177/154405910608501209] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The relative duration of muscle activity during a specified period (duty time) varies depending on activity level and time of the day. Since both the number and the length of activity bursts contribute to the duty time, it was hypothesized that these variables would show intra-day variations similar to those of the duty time. To test this, we determined duty times, burst numbers, and burst lengths per hour, in relation to multiple activity levels, in a 24-hour period of concurrent radio-telemetric long-term electromyograms of various rabbit jaw muscles. The marked intra-day variation of the burst number resembled that of the duty time in all muscles, and was in contrast to the relatively invariable mean burst length. Furthermore, the duty times were more highly correlated with the number than with the length of bursts at all activity levels. Thus, the variation of the duty time in rabbit jaw muscles is caused mainly by changes in burst numbers.
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Affiliation(s)
- T Grünheid
- Department of Orthodontics, Academic Center for Dentistry Amsterdam, Universiteit van Amsterdam, The Netherlands.
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27
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Srinivasan S, Ausk BJ, Bain SD, Gardiner EM, Kwon RY, Gross TS. Rest intervals reduce the number of loading bouts required to enhance bone formation. Med Sci Sports Exerc 2016; 47:1095-103. [PMID: 25207932 DOI: 10.1249/mss.0000000000000509] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PURPOSE As our society becomes increasingly sedentary, compliance with exercise regimens that require numerous high-energy activities each week become less likely. Alternatively, given an osteogenic exercise intervention that required minimal effort, it is reasonable to presume that participation would be enhanced. Insertion of brief rest intervals between each cycle of mechanical loading holds potential to achieve this result because substantial osteoblast function is activated by many fewer loading repetitions within each loading bout. Here, we examined the complementary hypothesis that the number of bouts per week of rest-inserted loading could be reduced from three bouts per week without loss of osteogenic efficacy. METHODS We conducted a series of 3-wk in vivo experiments that noninvasively exposed the right tibiae of mice to either cyclic (1 Hz) or rest-inserted loading interventions and quantified osteoblast function via dynamic histomorphometry. RESULTS Although reducing loading bouts from three bouts per week (i.e., nine total bouts) to one bout per week (i.e., three total bouts) effectively mitigated the osteogenic benefit of cyclic loading, the same reduction did not significantly reduce periosteal bone formation parameters induced by rest-inserted loading. The osteogenic response was robust to the timing of the rest-inserted loading bouts (three bouts in the first week vs one bout per week for 3 wk). However, elimination of any single bout of the three one-bout-per-week bouts mitigated the osteogenic response to rest-inserted loading. Finally, periosteal osteoblast function assessed after the 3-wk intervention was not sensitive to the timing or number of rest-inserted loading bouts. CONCLUSIONS We conclude that rest-inserted loading holds potential to retain the osteogenic benefits of mechanical loading with significantly reduced frequency of bouts of activity while also enabling greater flexibility in the timing of the activity.
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Affiliation(s)
- Sundar Srinivasan
- Department of Orthopaedics and Sports Medicine, University of Washington, Seattle, WA
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A visco-poroelastic model of functional adaptation in bones reconstructed with bio-resorbable materials. Biomech Model Mechanobiol 2016; 15:1325-43. [DOI: 10.1007/s10237-016-0765-6] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Accepted: 01/16/2016] [Indexed: 10/22/2022]
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29
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Bone mineral density, microarchitectural and mechanical alterations of osteoporotic rat bone under long-term whole-body vibration therapy. J Mech Behav Biomed Mater 2016; 53:341-349. [DOI: 10.1016/j.jmbbm.2015.08.040] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Revised: 08/22/2015] [Accepted: 08/29/2015] [Indexed: 11/21/2022]
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Hu M, Tian GW, Gibbons DE, Jiao J, Qin YX. Dynamic fluid flow induced mechanobiological modulation of in situ osteocyte calcium oscillations. Arch Biochem Biophys 2015; 579:55-61. [PMID: 26045248 DOI: 10.1016/j.abb.2015.05.012] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Revised: 05/23/2015] [Accepted: 05/27/2015] [Indexed: 01/20/2023]
Abstract
Distribution of intramedullary pressure (ImP) induced bone fluid flow has been suggested to influence the magnitude of mechanotransductory signals within bone. As osteocytes have been suggested as major mechanosensors in bone network, it is still unclear how osteocytes embedded within a mineralized bone matrix respond to the external mechanical stimuli derived from direct coupling of dynamic fluid flow stimulation (DFFS). While in vitro osteocytes show unique Ca(2+) oscillations to fluid shear, the objective of this study was to use a confocal imaging technique to visualize and quantify Ca(2+) responses in osteocytes in situ under DFFS into the marrow cavity of an intact ex vivo mouse femur. This study provided significant technical development for evaluating mechanotransduction mechanism in bone cell response by separation of mechanical strain and fluid flow factors using ImP stimulation, giving the ability for true real-time imaging and monitoring of bone cell activities during the stimulation. Loading frequency dependent Ca(2+) oscillations in osteocytes indicated the optimized loading at 10Hz, where such induced response was significantly diminished via blockage of the Wnt/β-catenin signaling pathway. The results provided a pilot finding of the potential crosstalk or interaction between Wnt/β-catenin signaling and Ca(2+) influx signaling of in situ osteocytes in response to mechanical signals. Findings from the present study make a valuable tool to investigate how in situ osteocytes respond and transduce mechanical signals, e.g. DFFS, as a central mechanosensor.
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Affiliation(s)
- Minyi Hu
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794-5281, United States
| | - Guo-Wei Tian
- CMIC-Two Photon Imaging Center, Stony Brook University, Stony Brook, NY 11794-5200, United States
| | - Daniel E Gibbons
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794-5281, United States
| | - Jian Jiao
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794-5281, United States
| | - Yi-Xian Qin
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794-5281, United States.
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31
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Bonewald LF. Does defective bone lead to defective muscle? J Bone Miner Res 2015; 30:593-5. [PMID: 25727709 DOI: 10.1002/jbmr.2491] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Accepted: 02/25/2015] [Indexed: 01/06/2023]
Affiliation(s)
- Lynda F Bonewald
- Department of Oral and Craniofacial Sciences, School of Dentistry, University of Missouri-Kansas City, Kansas City, MO, USA
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32
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Yang PF, Kriechbaumer A, Albracht K, Sanno M, Ganse B, Koy T, Shang P, Brüggemann GP, Müller LP, Rittweger J. On the relationship between tibia torsional deformation and regional muscle contractions in habitual human exercises in vivo. J Biomech 2015; 48:456-64. [DOI: 10.1016/j.jbiomech.2014.12.031] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Revised: 12/02/2014] [Accepted: 12/05/2014] [Indexed: 11/16/2022]
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Sasso GRDS, Florencio-Silva R, Santos MA, Teixeira CDP, Simões MDJ, Katchburian E, Reginato RD. Effects of early and late treatments of low-intensity, high-frequency mechanical vibration on bone parameters in rats. Gynecol Endocrinol 2015; 31:980-6. [PMID: 26291818 DOI: 10.3109/09513590.2015.1075198] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Low-intensity, high-frequency mechanical vibration (LHMV) has shown to increase bone formation. However, studies comparing the effectiveness of early- and late-treatments of LHMV to counteract bone loss have not been documented. This study was designed to compare the effects of early- and late-treatments of LHMV (at 30 Hz/0.6 g, 20 min per day/five days per week, for 12 weeks) on bone parameters in ovariectomized (Ovx) rats. Thirty days after ovariectomy, 40 adult rats were randomly divided into four groups: GI (early control group); GII treated with LHMV 3 weeks after Ovx (early treatment); GIII (late control group) and GIV treated with LHMV twelve weeks after Ovx (late treatment). Bone mineral density (BMD) was analyzed before Ovx and after treatments. Then, animals were killed, and the femurs were collected and their length and diaphysis diameter were measured; the distal femurs were taken and processed for histomorphometry and polarized light microscopy for collagen fibers analysis or subjected to immunohistochemistry of cleaved caspase-3 in osteocytes. Statistical analysis was done by ANOVA followed by the Bonferroni post hoc test (p < 0.05). BMD was similar among the groups before Ovx, but after treatments, it was significantly higher in GII and GIV compared with their control groups (p < 0.05). Femur length and cortical bone thickness were similar among the groups, but the diaphysis diameter of GII was higher compared with GI. Trabecular bone area was higher in the vibrated groups, but it was greater in GII (p < 0.05). Also, the vibrated groups showed the higher content collagen fibers and lower presence apoptotic osteocytes (positive caspase-3 immunoreactivity) when compared with the other groups (p < 0.05). These results suggest that both early- and late-treatments with LHMV counteract bone loss, being the early treatment more effective than the late treatment.
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Affiliation(s)
| | - Rinaldo Florencio-Silva
- a Department of Morphology and Genetics , Federal University of São Paulo , São Paulo , Brazil
| | - Miriam Aparecida Santos
- a Department of Morphology and Genetics , Federal University of São Paulo , São Paulo , Brazil
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Hu M, Cheng J, Bethel N, Serra-Hsu F, Ferreri S, Lin L, Qin YX. Interrelation between external oscillatory muscle coupling amplitude and in vivo intramedullary pressure related bone adaptation. Bone 2014; 66:178-81. [PMID: 24947450 PMCID: PMC4125428 DOI: 10.1016/j.bone.2014.05.018] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2014] [Revised: 05/28/2014] [Accepted: 05/30/2014] [Indexed: 11/21/2022]
Abstract
Interstitial bone fluid flow (IBFF) is suggested as a communication medium that bridges external physical signals and internal cellular activities in the bone, which thus regulates bone remodeling. Intramedullary pressure (ImP) is one main regulatory factor of IBFF and bone adaptation related mechanotransduction. Our group has recently observed that dynamic hydraulic stimulation (DHS), as an external oscillatory muscle coupling, was able to induce local ImP with minimal bone strain as well as to mitigate disuse bone loss. The current study aimed to evaluate the dose dependent relationship between DHS's amplitude, i.e., 15 and 30mmHg, and in vivo ImP induction, as well as this correlation on bone's phenotypic change. Simultaneous measurements of ImP and DHS cuff pressures were obtained from rats under DHS with various magnitudes and a constant frequency of 2Hz. ImP inductions and cuff pressures upon DHS loading showed a positively proportional response over the amplitude sweep. The relationship between ImP and DHS cuff pressure was evaluated and shown to be proportional, in which ImP was raised with increases of DHS cuff pressure amplitudes (R(2)=0.98). A 4-week in vivo experiment using a rat hindlimb suspension model demonstrated that the mitigation effect of DHS on disuse trabecular bone was highly dose dependent and related to DHS's amplitude, where a higher ImP led to a higher bone volume. This study suggested that sufficient physiological DHS is needed to generate ImP. Oscillatory DHS, potentially induces local fluid flow, has shown dose dependence in attenuation of disuse osteopenia.
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Affiliation(s)
- Minyi Hu
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794-5281, USA
| | - Jiqi Cheng
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794-5281, USA
| | - Neville Bethel
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794-5281, USA
| | - Frederick Serra-Hsu
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794-5281, USA
| | - Suzanne Ferreri
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794-5281, USA
| | - Liangjun Lin
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794-5281, USA
| | - Yi-Xian Qin
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794-5281, USA.
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35
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Age-related changes in mouse bone permeability. J Biomech 2014; 47:1110-6. [DOI: 10.1016/j.jbiomech.2013.12.020] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2013] [Revised: 11/04/2013] [Accepted: 12/16/2013] [Indexed: 01/29/2023]
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Hu M, Serra-Hsu F, Bethel N, Lin L, Ferreri S, Cheng J, Qin YX. Dynamic hydraulic fluid stimulation regulated intramedullary pressure. Bone 2013; 57:137-41. [PMID: 23895997 PMCID: PMC3832679 DOI: 10.1016/j.bone.2013.07.030] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Revised: 07/03/2013] [Accepted: 07/23/2013] [Indexed: 11/23/2022]
Abstract
Physical signals within the bone, i.e. generated from mechanical loading, have the potential to initiate skeletal adaptation. Strong evidence has pointed to bone fluid flow (BFF) as a media between an external load and the bone cells, in which altered velocity and pressure can ultimately initiate the mechanotransduction and the remodeling process within the bone. Load-induced BFF can be altered by factors such as intramedullary pressure (ImP) and/or bone matrix strain, mediating bone adaptation. Previous studies have shown that BFF induced by ImP alone, with minimum bone strain, can initiate bone remodeling. However, identifying induced ImP dynamics and bone strain factor in vivo using a non-invasive method still remains challenging. To apply ImP as a means for alteration of BFF, it was hypothesized that non-invasive dynamic hydraulic stimulation (DHS) can induce local ImP with minimal bone strain to potentially elicit osteogenic adaptive responses via bone-muscle coupling. The goal of this study was to evaluate the immediate effects on local and distant ImP and strain in response to a range of loading frequencies using DHS. Simultaneous femoral and tibial ImP and bone strain values were measured in three 15-month-old female Sprague Dawley rats during DHS loading on the tibia with frequencies of 1Hz to 10Hz. DHS showed noticeable effects on ImP induction in the stimulated tibia in a nonlinear fashion in response to DHS over the range of loading frequencies, where they peaked at 2Hz. DHS at various loading frequencies generated minimal bone strain in the tibiae. Maximal bone strain measured at all loading frequencies was less than 8με. No detectable induction of ImP or bone strain was observed in the femur. This study suggested that oscillatory DHS may regulate the local fluid dynamics with minimal mechanical strain in the bone, which serves critically in bone adaptation. These results clearly implied DHS's potential as an effective, non-invasive intervention for osteopenia and osteoporosis treatments.
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Affiliation(s)
| | | | | | | | | | | | - Yi-Xian Qin
- Corresponding Author: Dept. of Biomedical Engineering Stony Brook University Bioengineering Bldg., Rm 215 Stony Brook, NY 11794-5281 Phone: 631-632-1481 Fax: 631-632-8577
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37
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Holguin N, Brodt MD, Sanchez ME, Kotiya AA, Silva MJ. Adaptation of tibial structure and strength to axial compression depends on loading history in both C57BL/6 and BALB/c mice. Calcif Tissue Int 2013; 93:211-21. [PMID: 23708853 PMCID: PMC3748612 DOI: 10.1007/s00223-013-9744-4] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2012] [Accepted: 05/05/2013] [Indexed: 11/25/2022]
Abstract
Tibial compression can increase murine bone mass. However, loading protocols and mouse strains differ between studies, which may contribute to conflicting results. We hypothesized that bone accrual is influenced more by loading history than by mouse strain or animal handling. The right tibiae of 4-month-old C57BL/6 and BALB/c mice were subjected to axial compression (10 N, 3 days/week, 6 weeks). Left tibiae served as contralateral controls to calculate relative changes: (loaded - control)/control. The WashU protocol applied 60 cycles/day, at 2 Hz, with a 10-s rest-insertion between cycles; the Cornell/HSS protocol applied 1,200 cycles/day, at 6.7 Hz, with a 0.1-s rest-insertion. Because sham loading, sedation, and transportation did not affect tibial morphology, unhandled mice served as age-matched controls (AC). Both loading protocols were anabolic for cortical bone, but Cornell/HSS loading elicited a more rapid response that was greater than WashU loading by 13 %. By 6 weeks, cortical bone volume of each loading group was greater than of AC (average + 16 %) and not different from each other. Ultimate displacement and energy to fracture were greater in tibiae loaded by either protocol, and ultimate force was greater with Cornell/HSS loading. At 6 weeks, independent of mouse strain, the WashU protocol produced minimal trabecular bone and the trabecular bone volume fraction of Cornell/HSS tibiae was greater than that of AC by 65 % and that of WashU by 44 %. We concluded that tibial adaptation to loading was more influenced by waveform than mouse strain or animal handling and therefore may have targeted similar osteogenic mechanisms in C57BL/6 and BALB/c mice.
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Affiliation(s)
- Nilsson Holguin
- Department of Orthopaedic Surgery, Washington University, 425 S Euclid Ave., St. Louis, MO 63110, USA.
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38
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Wagner DW, Chan S, Castillo AB, Beaupre GS. Geometric mouse variation: Implications to the axial ulnar loading protocol and animal specific calibration. J Biomech 2013; 46:2271-6. [DOI: 10.1016/j.jbiomech.2013.06.027] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2013] [Revised: 06/13/2013] [Accepted: 06/14/2013] [Indexed: 10/26/2022]
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39
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Lambers FM, Koch K, Kuhn G, Ruffoni D, Weigt C, Schulte FA, Müller R. Trabecular bone adapts to long-term cyclic loading by increasing stiffness and normalization of dynamic morphometric rates. Bone 2013; 55:325-34. [PMID: 23624292 DOI: 10.1016/j.bone.2013.04.016] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Revised: 04/18/2013] [Accepted: 04/19/2013] [Indexed: 10/26/2022]
Abstract
Bone has the ability to adapt to external loading conditions. Especially the beneficial effect of short-term cyclic loading has been investigated in a number of in vivo animal studies. The aim of this study was to assess the long-term effect (>10 weeks) of cyclic mechanical loading on the bone microstructure, bone stiffness, and bone remodeling rates. Mice were subjected to cyclic mechanical loading at the sixth caudal vertebra with 8N or 0N (control) three times per week for a total period of 14 weeks. Structural bone parameters were determined from in vivo micro-computed tomography (micro-CT) scans performed at week 0, 4, 6, 8, 10, 12, and 14. Mechanical parameters were derived from micro-finite element analysis. Dynamic bone morphometry was calculated using registration of serial micro-CT scans. Bone volume fraction and trabecular thickness increased significantly more for the loaded group than for the control group (p = 0.006 and p = 0.002 respectively). The trabecular bone microstructure adapted to the load of 8N in approximately ten weeks, indicated by the trabecular bone volume fraction, which increased from 16.7% at 0 weeks to 21.6% at week 10 and only showed little change afterwards (bone volume fraction of 21.5% at 14 weeks). Similarly bone stiffness - (at the start of the experiment 649N/mm) - reached 846N/mm at 10 weeks in the loaded group and was maintained to the end of the experiment (850N/mm). At 4 weeks the bone formation rate was 32% greater and the bone resorption rate 22% less for 8N compared to 0N. This difference was significantly reduced as the bone adapted to 8N, with 8N remodeling rates returning to the values of the 0N group at approximately 10 weeks. Together these data suggest that once bone has adapted to a new loading state, the remodeling rates reduce gradually while maintaining bone volume fraction and stiffness.
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Affiliation(s)
- Floor M Lambers
- Institute for Biomechanics, ETH Zürich, Wolfgang-Pauli-Str. 10, 8093 Zürich, Switzerland.
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40
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Webster DJ, Schneider P, Dallas SL, Müller R. Studying osteocytes within their environment. Bone 2013; 54:285-95. [PMID: 23318973 PMCID: PMC3652555 DOI: 10.1016/j.bone.2013.01.004] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2012] [Revised: 12/29/2012] [Accepted: 01/03/2013] [Indexed: 01/13/2023]
Abstract
It is widely hypothesized that osteocytes are the mechano-sensors residing in the bone's mineralized matrix which control load induced bone adaptation. Owing to their inaccessibility it has proved challenging to generate quantitative in vivo experimental data which supports this hypothesis. Recent advances in in situ imaging, both in non-living and living specimens, have provided new insights into the role of osteocytes in the skeleton. Combined with the retrieval of biochemical information from mechanically stimulated osteocytes using in vivo models, quantitative experimental data is now becoming available which is leading to a more accurate understanding of osteocyte function. With this in mind, here we review i) state of the art ex vivo imaging modalities which are able to precisely capture osteocyte structure in 3D, ii) live cell imaging techniques which are able to track structural morphology and cellular differentiation in both space and time, and iii) in vivo models which when combined with the latest biochemical assays and microfluidic imaging techniques can provide further insight on the biological function of osteocytes.
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Affiliation(s)
| | | | - Sarah L. Dallas
- School of Dentistry, Department of Oral Biology, University of Missouri, Kansas City, MO, USA
| | - Ralph Müller
- Institute for Biomechanics, ETH Zurich, Zurich, Switzerland
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Pereira AF, Shefelbine SJ. The influence of load repetition in bone mechanotransduction using poroelastic finite-element models: the impact of permeability. Biomech Model Mechanobiol 2013; 13:215-25. [DOI: 10.1007/s10237-013-0498-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2012] [Accepted: 05/04/2013] [Indexed: 10/26/2022]
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42
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Resonance in the mouse tibia as a predictor of frequencies and locations of loading-induced bone formation. Biomech Model Mechanobiol 2013; 13:141-51. [PMID: 23575747 DOI: 10.1007/s10237-013-0491-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2012] [Accepted: 04/01/2013] [Indexed: 01/15/2023]
Abstract
To enhance new bone formation for the treating of patients with osteopenia and osteoporosis, various mechanical loading regimens have been developed. Although a wide spectrum of loading frequencies is proposed in those regimens, a potential linkage between loading frequencies and locations of loading-induced bone formation is not well understood. In this study, we addressed a question: Does mechanical resonance play a role in frequency-dependent bone formation? If so, can the locations of enhanced bone formation be predicted through the modes of vibration? Our hypothesis is that mechanical loads applied at a frequency near the resonant frequencies enhance bone formation, specifically in areas that experience high principal strains. To test the hypothesis, we conducted axial tibia loading using low, medium, or high frequency to the mouse tibia, as well as finite element analysis. The experimental data demonstrated dependence of the maximum bone formation on location and frequency of loading. Samples loaded with the low-frequency waveform exhibited peak enhancement of bone formation in the proximal tibia, while the high-frequency waveform offered the greatest enhancement in the midshaft and distal sections. Furthermore, the observed dependence on loading frequencies was correlated to the principal strains in the first five resonance modes at 8.0-42.9 Hz. Collectively, the results suggest that resonance is a contributor to the frequencies and locations of maximum bone formation. Further investigation of the observed effects of resonance may lead to the prescribing of personalized mechanical loading treatments.
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Vanleene M, Shefelbine SJ. Therapeutic impact of low amplitude high frequency whole body vibrations on the osteogenesis imperfecta mouse bone. Bone 2013; 53:507-14. [PMID: 23352925 PMCID: PMC3590448 DOI: 10.1016/j.bone.2013.01.023] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/19/2012] [Revised: 01/10/2013] [Accepted: 01/11/2013] [Indexed: 12/26/2022]
Abstract
Osteogenesis imperfecta (OI) is characterized by extremely brittle bone. Currently, bisphosphonate drugs allow a decrease of fracture by inhibiting bone resorption and increasing bone mass but with possible long term side effects. Whole body mechanical vibrations (WBV) treatment may offer a promising route to stimulate bone formation in OI patients as it has exhibited health benefits on both muscle and bone mass in human and animal models. The present study has investigated the effects of WBV (45Hz, 0.3g, 15minutes/days, 5days/week) in young OI (oim) and wild type female mice from 3 to 8weeks of age. Vibration therapy resulted in a significant increase in the cortical bone area and cortical thickness in the femur and tibia diaphysis of both vibrated oim and wild type mice compared to sham controls. Trabecular bone was not affected by vibration in the wild type mice; vibrated oim mice, however, exhibited significantly higher trabecular bone volume fraction in the proximal tibia. Femoral stiffness and yield load in three point bending were greater in the vibrated wild type mice than in sham controls, most likely attributed to the increase in femur cortical cross sectional area observed in the μCT morphology analyses. The vibrated oim mice showed a trend toward improved mechanical properties, but bending data had large standard deviations and there was no significant difference between vibrated and non-vibrated oim mice. No significant difference of the bone apposition was observed in the tibial metaphyseal trabecular bone for both the oim and wild type vibrated mice by histomorphometry analyses of calcein labels. At the mid diaphysis, the cortical bone apposition was not significantly influenced by the WBV treatment in both the endosteum and periosteum of the oim vibrated mice while a significant change is observed in the endosteum of the vibrated wild type mice. As only a weak impact in bone apposition between the vibrated and sham groups is observed in the histological sections, it is possible that WBV reduced bone resorption, resulting in a relative increase in cortical thickness. Whole body vibration appears as a potential effective and innocuous means for increasing bone formation and strength, which is particularly attractive for treating the growing skeleton of children suffering from brittle bone disease or low bone density pathologies without the long term disadvantages of current pharmacological therapies.
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Affiliation(s)
- Maximilien Vanleene
- Corresponding author at: Department of Bioengineering, Imperial College London, Royal School of Mines Building, South Kensington Campus, London, SW7 2AZ, UK.
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Lambers FM, Stuker F, Weigt C, Kuhn G, Koch K, Schulte FA, Ripoll J, Rudin M, Müller R. Longitudinal in vivo imaging of bone formation and resorption using fluorescence molecular tomography. Bone 2013; 52:587-95. [PMID: 23142804 DOI: 10.1016/j.bone.2012.11.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2012] [Revised: 10/24/2012] [Accepted: 11/01/2012] [Indexed: 11/23/2022]
Abstract
Bone research often focuses on anatomical imaging of the bone microstructure, but in order to gain better understanding in how bone remodeling is modulated through interventions also bone formation and resorption processes should be investigated. With this in mind, the purpose of this study was to establish a longitudinal in vivo imaging approach of bone formation and resorption using fluorescence molecular tomography (FMT). In this study the reproducibility, accuracy and sensitivity of FMT for bone imaging were assessed by performing longitudinal measurements with FMT and comparing it to in vivo micro-computed tomography on a set of control mice, and mice in which load-adaptation was induced in the sixth caudal vertebra. The precision error for FMT measurements, expressed as coefficient of variation, was smaller than 16%, indicating acceptable reproducibility. A correlation was found between bone resorption measured with FMT and bone resorption rate measured with in vivo micro-computed tomography only over the first 14days (R=0.81, p<0.01), but not between bone formation measured with FMT and bone formation rate measured with in vivo micro-CT. Bone formation measured by FMT was 89-109% greater (p<0.05) for mice subjected to mechanical loading than control mice. Bone resorption was 5-8% lower, but did not reach a significant difference between groups, indicating moderate sensitivity for FMT. In conclusion, in vivo FMT in mouse tail bones is feasible but needs to be optimized for monitoring load adaptation in living mice.
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Affiliation(s)
- F M Lambers
- Institute for Biomechanics, ETH Zürich, Zürich, Switzerland
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Abstract
Bone responds to supraphysiological mechanical loads by increasing bone formation. Depending on the applied strain magnitude (and other loading parameters) the response can be either adaptive (mostly lamellar bone) or injury (mostly woven bone). Seminal studies of Hert, Lanyon, and Rubin originally established the basic "rules" of bone mechanosensitivity. These were reinforced by subsequent studies using non-invasive rodent loading models, most notably by Turner et al. More recent work with these models have been able to explore the structural, transcriptional, and molecular mechanisms which distinguish the two responses (lamellar vs. woven). Wnt/Lrp signaling has emerged as a key mechanoresponsive pathway for lamellar bone. However, there is still much to study with regard to effects of ageing, osteocytes, other signaling pathways, and the molecular regulation that modulates lamellar vs. woven bone formation. This review summarizes not only the historical findings but also the current data for these topics.
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Hu M, Cheng J, Qin YX. Dynamic hydraulic flow stimulation on mitigation of trabecular bone loss in a rat functional disuse model. Bone 2012; 51:819-25. [PMID: 22820398 PMCID: PMC3437383 DOI: 10.1016/j.bone.2012.06.030] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2012] [Revised: 06/21/2012] [Accepted: 06/25/2012] [Indexed: 11/20/2022]
Abstract
Bone fluid flow (BFF) has been demonstrated as a critical regulator in mechanotransductive signaling and bone adaptation. Intramedullary pressure (ImP) and matrix strain have been identified as potential generators to regulate BFF. To elevate in vivo oscillatory BFF using ImP, a dynamic hydraulic stimulation (DHS) approach was developed. The objective of this study was to evaluate the effects of DHS on mitigation of bone loss and structural alteration in a rat hindlimb suspension (HLS) functional disuse model. Sixty-one 5-month old female Sprague-Dawley rats were divided into five groups: 1) baseline control, 2) age-matched control, 3) HLS, 4) HLS+static loading, and 5) HLS+DHS. Hydraulic flow stimulation was carried out daily on a "10 min on-5 min off-10 min on" loading regime, 5 days/week, for a total of 4 weeks in the tibial region. The metaphyseal trabecular regions of the proximal tibiae were analyzed using μCT and histomorphometry. Four weeks of HLS resulted in a significant loss of trabecular bone, leading to structural deterioration. HLS with static loading alone was not sufficient to attenuate the bone loss. Bone quantity and microarchitecture were significantly improved by applying DHS loading, resulting increase of 83% in bone volume fraction, 25% in trabecular number and mitigation of 26% in trabecular separation compared to HLS control. Histomorphometry analysis on trabecular mineralization coincided with the μCT analysis, in which DHS loading yielded increases of 34% in histomorphometric BV/TV, 121% in MS/BS, 190% in BFR/BS and 146% in BFR/BV, compared to the HLS control. Overall, the data demonstrated that dynamic hydraulic flow loading has potentials to provide regulatory signals for mitigating bone loss induced by functional disuse. This approach may provide a new alternative mechanical intervention for future clinical treatment for osteoporosis.
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Affiliation(s)
| | | | - Yi-Xian Qin
- Corresponding Author: Yi-Xian Qin, Ph.D., Dept. of Biomedical Engineering, Stony Brook University, Bioengineering Bldg., Rm 215, Stony Brook, NY 11794-5281, Phone: 631-632-1481, Fax: 631-632-8577,
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Niziolek PJ, Warman ML, Robling AG. Mechanotransduction in bone tissue: The A214V and G171V mutations in Lrp5 enhance load-induced osteogenesis in a surface-selective manner. Bone 2012; 51:459-65. [PMID: 22750014 PMCID: PMC3784262 DOI: 10.1016/j.bone.2012.05.023] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2012] [Revised: 05/08/2012] [Accepted: 05/25/2012] [Indexed: 10/28/2022]
Abstract
Mechanotransduction in bone requires components of the Wnt signaling pathway to produce structurally adapted bone elements. In particular, the Wnt co-receptor LDL-receptor-related protein 5 (LRP5) appears to be a crucial protein in the mechanotransduction cascades that translate physical tissue deformation into new bone formation. Recently discovered missense mutations in LRP5 are associated with high bone mass (HBM), and the altered function of these proteins provide insight into LRP5 function in many skeletal processes, including mechanotransduction. We further investigated the role of LRP5 in bone cell mechanotransduction by applying mechanical stimulation in vivo to two different mutant mouse lines, which harbor HBM-causing missense mutations in Lrp5. Axial tibia loading was applied to mature male Lrp5 G171V and Lrp5 A214V knock-in mice, and to their wild type controls. Fluorochrome labeling revealed that 3 days of loading resulted in a significantly enhanced periosteal response in the A214V knock in mice, whereas the G171V mice exhibited a lowered osteogenic threshold on the endocortical surface. In summary, our data further highlight the importance of Lrp5 in bone cell mechanotransduction, and indicate that the HBM-causing mutations in Lrp5 can alter the anabolic response to mechanical stimulation in favor of increased bone gain.
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Affiliation(s)
- Paul J. Niziolek
- Department of Anatomy & Cell Biology, Indiana University School of Medicine, Indianapolis, IN, USA
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA
| | - Matthew L. Warman
- Department of Orthopaedic Surgery, Children’s Hospital, Boston, MA, USA
- Howard Hughes Medical Institute, Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Alexander G. Robling
- Department of Anatomy & Cell Biology, Indiana University School of Medicine, Indianapolis, IN, USA
- Department of Biomedical Engineering, Indiana University-Purdue University at Indianapolis (IUPUI), Indianapolis, IN, USA
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48
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Toward Mechanical Systems Biology in Bone. Ann Biomed Eng 2012; 40:2475-87. [DOI: 10.1007/s10439-012-0594-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2012] [Accepted: 05/10/2012] [Indexed: 11/25/2022]
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Chennimalai Kumar N, Dantzig JA, Jasiuk IM. Modeling of cortical bone adaptation in a rat ulna: effect of frequency. Bone 2012; 50:792-7. [PMID: 22210383 DOI: 10.1016/j.bone.2011.12.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2011] [Revised: 12/11/2011] [Accepted: 12/13/2011] [Indexed: 11/23/2022]
Abstract
We employ a recently developed model for the adaptation of cortical bone in response to mechanical loading to study the effect of loading frequency on the computed response, and we compare our results to previous experimental measurements on rat ulnae. We represent the cortical bone as a poroelastic material with orthotropic permeability. Bone adaptation in the model is related to a mechanical stimulus derived from the dissipation energy of the poroelastic flow induced by deformation. We account for a non-locality in the mechanotransduction of osteocytes present in the lacunae by using a "zone of influence." Calculations are done using the finite element method applied to a rat ulna whose geometry is obtained from micro-computed tomography images. We show that the change in the second moment of inertia of the cross-section increases non-linearly and saturates at higher frequency range. The numerical results are then compared quantitatively to experimental data from the literature. Finally, we examine the role of local narrowing of intramedullary canal in our specific ulna in the development of local irregularities in growth.
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Affiliation(s)
- N Chennimalai Kumar
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, 1206 West Green Street, Urbana, IL 61801, USA
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Macione J, Nesbitt S, Pandit V, Kotha S. Design and analysis of a novel mechanical loading machine for dynamic in vivo axial loading. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2012; 83:025113. [PMID: 22380131 PMCID: PMC3298551 DOI: 10.1063/1.3687781] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2011] [Accepted: 02/04/2012] [Indexed: 05/31/2023]
Abstract
This paper describes the construction of a loading machine for performing in vivo, dynamic mechanical loading of the rodent forearm. The loading machine utilizes a unique type of electromagnetic actuator with no mechanically resistive components (servotube), allowing highly accurate loads to be created. A regression analysis of the force created by the actuator with respect to the input voltage demonstrates high linear correlation (R(2) = 1). When the linear correlation is used to create dynamic loading waveforms in the frequency (0.5-10 Hz) and load (1-50 N) range used for in vivo loading, less than 1% normalized root mean square error (NRMSE) is computed. Larger NRMSE is found at increased frequencies, with 5%-8% occurring at 40 Hz, and reasons are discussed. Amplifiers (strain gauge, linear voltage displacement transducer (LVDT), and load cell) are constructed, calibrated, and integrated, to allow well-resolved dynamic measurements to be recorded at each program cycle. Each of the amplifiers uses an active filter with cutoff frequency at the maximum in vivo loading frequencies (50 Hz) so that electronic noise generated by the servo drive and actuator are reduced. The LVDT and load cell amplifiers allow evaluation of stress-strain relationships to determine if in vivo bone damage is occurring. The strain gauge amplifier allows dynamic force to strain calibrations to occur for animals of different sex, age, and strain. Unique features are integrated into the loading system, including a weightless mode, which allows the limbs of anesthetized animals to be quickly positioned and removed. Although the device is constructed for in vivo axial bone loading, it can be used within constraints, as a general measurement instrument in a laboratory setting.
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Affiliation(s)
- James Macione
- Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180, USA.
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