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Szczesny SE, Corr DT. Tendon cell and tissue culture: Perspectives and recommendations. J Orthop Res 2023; 41:2093-2104. [PMID: 36794495 DOI: 10.1002/jor.25532] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 01/19/2023] [Accepted: 02/08/2023] [Indexed: 02/17/2023]
Abstract
The wide variety of cell and tissue culture systems used to study and engineer tendons can make it difficult to choose the best approach and "optimal" culture conditions to test a given hypothesis. Therefore, a breakout session was organized at the 2022 ORS Tendon Section Meeting that focused on establishing a set of guidelines for conducting cell and tissue culture studies of tendon. This paper summarizes the outcomes of that discussion and presents recommendations for future studies. In the case of studying tendon cell behavior, cell and tissue culture systems are reductionist models in which the culture conditions should be strictly defined to approximate the in vivo condition as closely as possible. In contrast, for tissue engineering tendon replacements, the culture conditions do not need to replicate native tendon, but the outcome measures for success should be narrowly defined for the specific clinical application. Common recommendations for both applications are that researchers should perform a baseline phenotypic characterization of the cells that are ultimately used for experimentation. For models of tendon cell behavior, culture conditions should be well justified by existing literature and meticulously reported, tissue explant viability should be assessed, and comparisons to in vivo conditions should be made to determine baseline physiological relevance. For tissue engineering applications, the functional/structural/compositional outcome targets should be defined by the specific tendons they seek to replace, with key biologic and material properties prioritized for construct assessment. Lastly, when engineering tendon replacements, researchers should utilize clinically approved cGMP materials to facilitate clinical translation.
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Affiliation(s)
- Spencer E Szczesny
- Department of Biomedical Engineering, Pennsylvania State University, University Park, Pennsylvania, USA
- Department of Orthopaedics and Rehabilitation, Pennsylvania State University, Hershey, Pennsylvania, USA
| | - David T Corr
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, New York, USA
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2
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Review of human supraspinatus tendon mechanics. Part I: fatigue damage accumulation and failure. J Shoulder Elbow Surg 2022; 31:2671-2677. [PMID: 35931330 DOI: 10.1016/j.jse.2022.06.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Revised: 06/10/2022] [Accepted: 06/27/2022] [Indexed: 02/01/2023]
Abstract
Repetitive stress injuries to the rotator cuff, and particularly the supraspinatus tendon (SST), are highly prevalent and debilitating. These injuries typically occur through the application of cyclic load below the threshold necessary to cause acute tears, leading to accumulation of incremental damage that exceeds the body's ability to heal, resulting in decreased mechanical strength and increased risk of frank rupture at lower loads. Consistent progression of fatigue damage across multiple model systems suggests a generalized tendon response to overuse. This finding may allow for interventions before gross injury of the SST occurs. Further research into the human SST response to fatigue loading is necessary to characterize the fatigue life of the tendon, which will help determine the frequency, duration, and magnitude of load spectra the SST may experience before injury. Future studies may allow in vivo SST strain analysis during specific activities, generation of a human SST stress-cycle curve, and characterization of damage and repair related to repetitive tasks.
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3
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Wu SY, Kim W, Kremen TJ. In Vitro Cellular Strain Models of Tendon Biology and Tenogenic Differentiation. Front Bioeng Biotechnol 2022; 10:826748. [PMID: 35242750 PMCID: PMC8886160 DOI: 10.3389/fbioe.2022.826748] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 01/17/2022] [Indexed: 11/19/2022] Open
Abstract
Research has shown that the surrounding biomechanical environment plays a significant role in the development, differentiation, repair, and degradation of tendon, but the interactions between tendon cells and the forces they experience are complex. In vitro mechanical stimulation models attempt to understand the effects of mechanical load on tendon and connective tissue progenitor cells. This article reviews multiple mechanical stimulation models used to study tendon mechanobiology and provides an overview of the current progress in modelling the complex native biomechanical environment of tendon. Though great strides have been made in advancing the understanding of the role of mechanical stimulation in tendon development, damage, and repair, there exists no ideal in vitro model. Further comparative studies and careful consideration of loading parameters, cell populations, and biochemical additives may further offer new insight into an ideal model for the support of tendon regeneration studies.
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Affiliation(s)
- Shannon Y. Wu
- David Geffen School of Medicine at UCLA, Los Angeles, CA, United States
| | - Won Kim
- Department of Rehabilitation Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea
| | - Thomas J. Kremen
- Department of Orthopaedic Surgery, David Geffen School of Medicine at UCLA, Los Angeles, CA, United States
- *Correspondence: Thomas J. Kremen Jr,
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4
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Al Makhzoomi AK, Kirk TB, Allison GT. A multiscale study of morphological changes in tendons following repeated cyclic loading. J Biomech 2021; 128:110790. [PMID: 34634539 DOI: 10.1016/j.jbiomech.2021.110790] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Revised: 09/30/2021] [Accepted: 09/30/2021] [Indexed: 11/30/2022]
Abstract
The response of white New Zealand rabbit Achilles tendons to load was assessed using mechanical measures and confocal arthroscopy (CA). The progression of fatigue-loading-induced damage of the macro- (tenocyte morphology, fiber anisotropy and waviness), as well as the mechanical profile, were assessed within the same non-viable intact tendon in response to prolonged cyclic and static loading (up to four hours) at different strain levels (3%, 6% and 9%). Strain-mediated repeated loading induced a significant decline in mechanical function (p < 0.05) with increased strain and cycles. Mechanical and structural resilience was lost with repeated loading (p < 0.05) at macroscales. The lengthening of D-periodicity correlated strongly with the overall tendon mechanical changes and loss of spindle shape in tenocytes. This is the first study to provide a clear concurrent assessment of form (morphology) and function (mechanics) of tendons undergoing different strain-mediated repeated loading at multiple-scale assessments. This study identifies a variety of multiscale properties that may contribute to the understanding of mechanisms of tendon pathology.
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Affiliation(s)
- Anas K Al Makhzoomi
- School of Allied Health, Faculty of Health Science, Curtin University, Perth, Western Australia, Australia.
| | - Thomas B Kirk
- School of Science, Engineering and Technology, RMIT University Vietnam, Ho Chi Minh City, Vietnam
| | - Garry T Allison
- Research Office, Curtin University, Perth, Western Australia, Australia
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5
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Williamson PM, Freedman BR, Kwok N, Beeram I, Pennings J, Johnson J, Hamparian D, Cohen E, Galloway JL, Ramappa AJ, DeAngelis JP, Nazarian A. Tendinopathy and tendon material response to load: What we can learn from small animal studies. Acta Biomater 2021; 134:43-56. [PMID: 34325074 DOI: 10.1016/j.actbio.2021.07.046] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 07/16/2021] [Accepted: 07/21/2021] [Indexed: 12/20/2022]
Abstract
Tendinopathy is a debilitating disease that causes as much as 30% of all musculoskeletal consultations. Existing treatments for tendinopathy have variable efficacy, possibly due to incomplete characterization of the underlying pathophysiology. Mechanical load can have both beneficial and detrimental effects on tendon, as the overall tendon response depends on the degree, frequency, timing, and magnitude of the load. The clinical continuum model of tendinopathy offers insight into the late stages of tendinopathy, but it does not capture the subclinical tendinopathic changes that begin before pain or loss of function. Small animal models that use high tendon loading to mimic human tendinopathy may be able to fill this knowledge gap. The goal of this review is to summarize the insights from in-vivo animal studies of mechanically-induced tendinopathy and higher loading regimens into the mechanical, microstructural, and biological features that help characterize the continuum between normal tendon and tendinopathy. STATEMENT OF SIGNIFICANCE: This review summarizes the insights gained from in-vivo animal studies of mechanically-induced tendinopathy by evaluating the effect high loading regimens have on the mechanical, structural, and biological features of tendinopathy. A better understanding of the interplay between these realms could lead to improved patient management, especially in the presence of painful tendon.
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6
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Al Makhzoomi AK, Kirk TB, Allison GT. An AFM study of the nanostructural response of New Zealand white rabbit Achilles tendons to cyclic loading. Microsc Res Tech 2021; 85:728-737. [PMID: 34632676 DOI: 10.1002/jemt.23944] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 08/14/2021] [Accepted: 09/09/2021] [Indexed: 01/21/2023]
Abstract
The nanostructural response of New Zealand white rabbit Achilles tendons to a fatigue damage model was assessed quantitatively and qualitatively using the endpoint of dose assessments of each tendon from our previous study. The change in mechanical properties was assessed concurrently with nanostructural change in the same non-viable intact tendon. Atomic force microscopy was used to study the elongation of D-periodicities, and the changes were compared both within the same fibril bundle and between fibril bundles. D-periodicities increased due to both increased strain and increasing numbers of fatigue cycles. Although no significant difference in D-periodicity lengthening was found between fibril bundles, the lengthening of D-periodicity correlated strongly with the overall tendon mechanical changes. The accurate quantification of fibril elongation in response to macroscopic applied strain assisted in assessing the complex structure-function relationship in Achilles tendons.
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Affiliation(s)
- Anas K Al Makhzoomi
- School of Allied Health, Faculty of Health Science, Curtin University, Perth, Western Australia, Australia
| | - Thomas B Kirk
- School of Science, Engineering and Technology, RMIT University Vietnam, Ho Chi Minh City, Vietnam
| | - Garry T Allison
- Associate Deputy Vice-Chancellor, Research Excellence, Curtin University, Perth, Western Australia, Australia
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7
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JOKAR HOSSEIN, ROUHI GHOLAMREZA, ABOLFATHI NABIOLLAH. THE ROLE OF PDL-CEMENTUM ENTHESIS IN PROTECTING PDL UNDER MASTICATORY LOADING: A FINITE ELEMENT INVESTIGATION. J MECH MED BIOL 2021. [DOI: 10.1142/s0219519421500494] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Background: The function of periodontal ligament (PDL)-cementum enthesis (PCE) in transferring the mechanical stimuli within the tooth–periodontium (PDT)–bone complex was not made clear yet. This study aimed to evaluate the effects of PCE on the mechanical stimuli distribution within the PDL and alveolar bone in the tooth–PDT–bone complex under occlusal forces using the finite element method. Methods: A computed tomography-based model of alveolar bone and second premolar of mandible was constructed, in which the PDT was considered at the interface of alveolar bone and tooth. Under a 3 MPa distributed occluso-apical masticatory load, applied over the uppermost surface of crown, the von Mises strain (vMST) and strain energy density (SED) within PDL, and von Mises stress (vMSR) and SED within alveolar bone were calculated in two situations: 1. When the PCE was absent; and 2. When the PCE was present between the PDL and cementum. Results: PCE levels-off SED and vMST within PDL up to 59% and 27%, respectively, compared to the model with no PCE. Moreover, in the alveolar bone, SEDs and vMSR increased up to 28% and 30%, respectively, compared to the model without PCE. Conclusion: By including PCE in the tooth–PDT–bone model, the mechanical stimuli shifted from PDL to its surrounding alveolar bone. Thus, it can be speculated that the tooth–PDT–bone complex has the capability of reducing the risk of PDL damage, through shifting excess mechanical stimuli from PDL toward the alveolar bone, during prolonged cyclic masticatory loading, as well as while one applies nonphysiologic and therapeutic loads, such as in orthodontic tooth movement.
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Affiliation(s)
- HOSSEIN JOKAR
- Faculty of Biomedical Engineering, Amirkabir University of Technology, Tehran, Iran
| | - GHOLAMREZA ROUHI
- Faculty of Biomedical Engineering, Amirkabir University of Technology, Tehran, Iran
| | - NABIOLLAH ABOLFATHI
- Faculty of Biomedical Engineering, Amirkabir University of Technology, Tehran, Iran
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8
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Dyment NA, Barrett JG, Awad H, Bautista CA, Banes A, Butler DL. A brief history of tendon and ligament bioreactors: Impact and future prospects. J Orthop Res 2020; 38:2318-2330. [PMID: 32579266 PMCID: PMC7722018 DOI: 10.1002/jor.24784] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 05/28/2020] [Accepted: 06/12/2020] [Indexed: 02/04/2023]
Abstract
Bioreactors are powerful tools with the potential to model tissue development and disease in vitro. For nearly four decades, bioreactors have been used to create tendon and ligament tissue-engineered constructs in order to define basic mechanisms of cell function, extracellular matrix deposition, tissue organization, injury, and tissue remodeling. This review provides a historical perspective of tendon and ligament bioreactors and their contributions to this advancing field. First, we demonstrate the need for bioreactors to improve understanding of tendon and ligament function and dysfunction. Next, we detail the history and evolution of bioreactor development and design from simple stretching of explants to fabrication and stimulation of two- and three-dimensional constructs. Then, we demonstrate how research using tendon and ligament bioreactors has led to pivotal basic science and tissue-engineering discoveries. Finally, we provide guidance for new basic, applied, and clinical research utilizing these valuable systems, recognizing that fundamental knowledge of cell-cell and cell-matrix interactions combined with appropriate mechanical and chemical stimulation of constructs could ultimately lead to functional tendon and ligament repairs in the coming decades.
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Affiliation(s)
- Nathaniel A. Dyment
- McKay Orthopaedic Research Laboratory, University of Pennsylvania, Philadelphia, PA
| | - Jennifer G. Barrett
- Department of Large Animal Clinical Sciences, Marion duPont Scott Equine Medical Center, Virginia Tech, Leesburg, VA
| | - Hani Awad
- Department of Biomedical Engineering, The Center for Musculoskeletal Research, University of Rochester, Rochester, NY 14627
| | | | - Albert Banes
- Flexcell International Corp., 2730 Tucker St., Suite 200, Burlington, 27215, NC
- Joint Department of Biomedical Engineering, University of North Carolina at Chapel Hill and North Carolina State University, Chapel Hill, NC
| | - David L. Butler
- Department of Biomedical Engineering, University of Cincinnati, Cincinnati, OH, 45221
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9
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Different Frequency of Cyclic Tensile Strain Relates to Anabolic/Catabolic Conditions Consistent with Immunohistochemical Staining Intensity in Tenocytes. Int J Mol Sci 2020; 21:ijms21031082. [PMID: 32041254 PMCID: PMC7037470 DOI: 10.3390/ijms21031082] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 01/24/2020] [Accepted: 02/02/2020] [Indexed: 01/13/2023] Open
Abstract
Tenocytes are mechanosensitive cells intimately adapting their expression profile and hence, their phenotype to their respective mechanomilieu. The immunolocalization and expression intensity of tenogenic, anabolic and catabolic markers in tenocytes in response to in vitro mechanical loading have not been monitored by immunohistochemical staining (IHC). Thus, we investigated the association between IHC intensities, different stimulation frequencies, and tenogenic metabolism using a versatile mechanical stretcher. Primary tenocytes obtained from murine Achilles tendons were transferred to poly(dimethylsiloxane) (PDMS) elastomeric chamber. Chambers were cyclically stretched by 5% in uniaxial direction at a variation of tensile frequency (1 or 2 Hz) for 3 h. After stretching, cell physiology, IHC intensities of tendon-related markers, and protein level of the angiogenesis marker vascular endothelial growth factor (VEGF) were evaluated. Cell proliferation in tenocytes stimulated with 1 Hz stretch was significantly higher than with 2 Hz or without stretch, while 2 Hz stretch induced significantly reduced cell viability and proliferation with microscopically detectable apoptotic cell changes. The amount of scleraxis translocated into the nuclei and tenomodulin immunoreactivity of tenocytes treated with stretch were significantly higher than of non-stretched cells. The collagen type-1 expression level in tenocytes stretched at 1 Hz was significantly higher than in those cultivated with 2 Hz or without stretching, whereas the matrix metalloproteinase (MMP)-1 and MMP-13 immunoreactivities of cells stretched at 2 Hz were significantly higher than in those stimulated with 1 Hz or without stretching. The secreted VEGF-protein level of tenocytes stretched at 2 Hz was significantly higher than without stretching. Our IHC findings consistent with cell physiology suggest that appropriate stretching can reproduce in vitro short-term tenogenic anabolic/catabolic conditions and allow us to identify an anabolic stretching profile.
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10
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Udeze CP, Jones ER, Riley GP, Morrissey D, Screen HRC. An in vitro investigation into the effects of 10 Hz cyclic loading on tenocyte metabolism. Scand J Med Sci Sports 2019; 29:1511-1520. [PMID: 31102473 DOI: 10.1111/sms.13465] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Revised: 03/25/2019] [Accepted: 04/30/2019] [Indexed: 12/25/2022]
Abstract
Tendinopathy is a prevalent, highly debilitating condition, with poorly defined etiology. A wide range of clinical treatments has been proposed, with systematic reviews largely supporting shock wave therapy or eccentric exercise. Characterizing these treatments have demonstrated both generate perturbations within tendon at a frequency of approximately 8-12 Hz. Consequently, it is hypothesized that loading in this frequency range initiates increased anabolic tenocyte behavior, promoting tendon repair. The primary aim of this study was to investigate the effects of 10 Hz perturbations on tenocyte metabolism, comparing gene expression in response to a 10 Hz and 1 Hz loading profile. Tenocytes from healthy and tendinopathic human tendons were seeded into 3D collagen gels and subjected to 15 minutes cyclic strain at 10 Hz or 1 Hz. Tenocytes from healthy tendon showed increased expression of all analyzed genes in response to loading, with significantly increased expression of inflammatory and degradative genes with 10 Hz, relative to 1 Hz loading. By contrast, whilst the response of tenocytes from tendinopathy tendon also increased with 10 Hz loading, the overall response profile was more varied and less intense, possibly indicative of an altered healing response. Through inhibition of the pathway, IL1 was shown to be involved in the degradative and catabolic response of cells to high-frequency loading, abrogating the loading response. This study has demonstrated for the first time that loading at a frequency of 10 Hz may enhance the metabolic response of tenocytes by initiating an immediate degradatory and inflammatory cell response through the IL1 pathway, perhaps as an initial stage of tendon healing.
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Affiliation(s)
- Chineye P Udeze
- School of Engineering and Material Science, Queen Mary University of London, London, UK
| | | | | | - Dylan Morrissey
- Sport and Exercise Medicine, Queen Mary University of London, London, UK.,Physiotherapy Department, Bart's Health NHS Trust, London, UK
| | - Hazel R C Screen
- School of Engineering and Material Science, Queen Mary University of London, London, UK
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11
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Freedman BR, Rodriguez AB, Leiphart RJ, Newton JB, Ban E, Sarver JJ, Mauck RL, Shenoy VB, Soslowsky LJ. Dynamic Loading and Tendon Healing Affect Multiscale Tendon Properties and ECM Stress Transmission. Sci Rep 2018; 8:10854. [PMID: 30022076 PMCID: PMC6052000 DOI: 10.1038/s41598-018-29060-y] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Accepted: 06/26/2018] [Indexed: 12/15/2022] Open
Abstract
The extracellular matrix (ECM) is the primary biomechanical environment that interacts with tendon cells (tenocytes). Stresses applied via muscle contraction during skeletal movement transfer across structural hierarchies to the tenocyte nucleus in native uninjured tendons. Alterations to ECM structural and mechanical properties due to mechanical loading and tissue healing may affect this multiscale strain transfer and stress transmission through the ECM. This study explores the interface between dynamic loading and tendon healing across multiple length scales using living tendon explants. Results show that macroscale mechanical and structural properties are inferior following high magnitude dynamic loading (fatigue) in uninjured living tendon and that these effects propagate to the microscale. Although similar macroscale mechanical effects of dynamic loading are present in healing tendon compared to uninjured tendon, the microscale properties differed greatly during early healing. Regression analysis identified several variables (collagen and nuclear disorganization, cellularity, and F-actin) that directly predict nuclear deformation under loading. Finite element modeling predicted deficits in ECM stress transmission following fatigue loading and during healing. Together, this work identifies the multiscale response of tendon to dynamic loading and healing, and provides new insight into microenvironmental features that tenocytes may experience following injury and after cell delivery therapies.
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Affiliation(s)
- Benjamin R Freedman
- McKay Orthopedic Research Laboratory, University of Pennsylvania, Philadelphia, PA, USA.,Department of Bioengineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, PA, USA.,John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA.,Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, USA
| | - Ashley B Rodriguez
- McKay Orthopedic Research Laboratory, University of Pennsylvania, Philadelphia, PA, USA
| | - Ryan J Leiphart
- McKay Orthopedic Research Laboratory, University of Pennsylvania, Philadelphia, PA, USA.,Department of Bioengineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, PA, USA
| | - Joseph B Newton
- McKay Orthopedic Research Laboratory, University of Pennsylvania, Philadelphia, PA, USA.,Department of Bioengineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, PA, USA
| | - Ehsan Ban
- Department of Materials Science and Engineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, PA, USA.,Center for Engineering Mechanobiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Joseph J Sarver
- Department of Biomedical Engineering, Drexel University, Philadelphia, PA, USA
| | - Robert L Mauck
- McKay Orthopedic Research Laboratory, University of Pennsylvania, Philadelphia, PA, USA.,Department of Bioengineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, PA, USA
| | - Vivek B Shenoy
- Department of Materials Science and Engineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, PA, USA.,Center for Engineering Mechanobiology, University of Pennsylvania, Philadelphia, PA, USA
| | - Louis J Soslowsky
- McKay Orthopedic Research Laboratory, University of Pennsylvania, Philadelphia, PA, USA. .,Department of Bioengineering, School of Engineering and Applied Science, University of Pennsylvania, Philadelphia, PA, USA.
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12
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Takatani KC, Bruchal LC. A new approach to prevent overuse injuries of the rotator cuff supraspinatus tendon using the cumulative fatigue concept. THEORETICAL ISSUES IN ERGONOMICS SCIENCE 2017. [DOI: 10.1080/1463922x.2017.1284281] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
| | - Liisa C. Bruchal
- Boeing Research & Technology, The Boeing Company, Seattle, WA, USA
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13
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Martin C, Sun W. Fatigue damage of collagenous tissues: experiment, modeling and simulation studies. J Long Term Eff Med Implants 2016; 25:55-73. [PMID: 25955007 DOI: 10.1615/jlongtermeffmedimplants.2015011749] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Mechanical fatigue damage is a critical issue for soft tissues and tissue-derived materials, particularly for musculoskeletal and cardiovascular applications; yet, our understanding of the fatigue damage process is incomplete. Soft tissue fatigue experiments are often difficult and time-consuming to perform, which has hindered progress in this area. However, the recent development of soft-tissue fatigue-damage constitutive models has enabled simulation-based fatigue analyses of tissues under various conditions. Computational simulations facilitate highly controlled and quantitative analyses to study the distinct effects of various loading conditions and design features on tissue durability; thus, they are advantageous over complex fatigue experiments. Although significant work to calibrate the constitutive models from fatigue experiments and to validate predictability remains, further development in these areas will add to our knowledge of soft-tissue fatigue damage and will facilitate the design of durable treatments and devices. In this review, the experimental, modeling, and simulation efforts to study collagenous tissue fatigue damage are summarized and critically assessed.
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Affiliation(s)
- Caitlin Martin
- Tissue Mechanics Laboratory, The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA 30313
| | - Wei Sun
- Tissue Mechanics Laboratory, The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA 30313
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14
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Freedman BR, Bade ND, Riggin CN, Zhang S, Haines PG, Ong KL, Janmey PA. The (dys)functional extracellular matrix. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1853:3153-64. [PMID: 25930943 DOI: 10.1016/j.bbamcr.2015.04.015] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Revised: 04/11/2015] [Accepted: 04/13/2015] [Indexed: 10/23/2022]
Abstract
The extracellular matrix (ECM) is a major component of the biomechanical environment with which cells interact, and it plays important roles in both normal development and disease progression. Mechanical and biochemical factors alter the biomechanical properties of tissues by driving cellular remodeling of the ECM. This review provides an overview of the structural, compositional, and mechanical properties of the ECM that instruct cell behaviors. Case studies are reviewed that highlight mechanotransduction in the context of two distinct tissues: tendons and the heart. Although these two tissues demonstrate differences in relative cell-ECM composition and mechanical environment, they share similar mechanisms underlying ECM dysfunction and cell mechanotransduction. Together, these topics provide a framework for a fundamental understanding of the ECM and how it may vary across normal and diseased tissues in response to mechanical and biochemical cues. This article is part of a Special Issue entitled: Mechanobiology.
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Affiliation(s)
- Benjamin R Freedman
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Nathan D Bade
- Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Corinne N Riggin
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Sijia Zhang
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Philip G Haines
- Division of Cardiovascular Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Katy L Ong
- Department of Cell and Developmental Biology, University of Pennsylvania, Philadelphia, PA, USA
| | - Paul A Janmey
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA; Department of Physiology, University of Pennsylvania, Philadelphia, PA, USA.
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15
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Shepherd JH, Riley GP, Screen HRC. Early stage fatigue damage occurs in bovine tendon fascicles in the absence of changes in mechanics at either the gross or micro-structural level. J Mech Behav Biomed Mater 2014; 38:163-72. [PMID: 25001495 PMCID: PMC4148183 DOI: 10.1016/j.jmbbm.2014.06.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Revised: 06/01/2014] [Accepted: 06/04/2014] [Indexed: 12/04/2022]
Abstract
Many tendon injuries are believed to result from repetitive motion or overuse, leading to the accumulation of micro-damage over time. In vitro fatigue loading can be used to characterise damage during repeated use and investigate how this may relate to the aetiology of tendinopathy. This study considered the effect of fatigue loading on fascicles from two functionally distinct bovine tendons: the digital extensor and deep digital flexor. Micro-scale extension mechanisms were investigated in fascicles before or after a period of cyclic creep loading, comparing two different measurement techniques – the displacement of a photo-bleached grid and the use of nuclei as fiducial markers. Whilst visual damage was clearly identified after only 300 cycles of creep loading, these visual changes did not affect either gross fascicle mechanics or fascicle microstructural extension mechanisms over the 900 fatigue cycles investigated. However, significantly greater fibre sliding was measured when observing grid deformation rather than the analysis of nuclei movement. Measurement of microstructural extension with both techniques was localised and this may explain the absence of change in microstructural deformation in response to fatigue loading. Alternatively, the data may demonstrate that fascicles can withstand a degree of matrix disruption with no impact on mechanics. Whilst use of a photo-bleached grid to directly measure the collagen is the best indicator of matrix deformation, nuclei tracking may provide a better measure of the strain perceived directly by the cells. Tendon fascicle gross mechanics and micro-scale deformation investigated after fatigue loading. Fascicles can withstand a degree of matrix disruption without impact on mechanics. More fibre sliding was observed measuring grid deformation than tracking nuclei. Nuclei tracking may better represent the strains experienced by cells than grid deformation.
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Affiliation(s)
- Jennifer H Shepherd
- Institute of Bioengineering, School of Engineering and Materials Science, Queen Mary, University of London, Mile End Road, E1 4NS, UK
| | - Graham P Riley
- School of Biological Sciences, University of East Anglia, UK
| | - Hazel R C Screen
- Institute of Bioengineering, School of Engineering and Materials Science, Queen Mary, University of London, Mile End Road, E1 4NS, UK.
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16
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Liu J, Chen L, zhou Y, Liu X, Tang K. Insulin-like growth factor-1 and bone morphogenetic protein-2 jointly mediate prostaglandin E2-induced adipogenic differentiation of rat tendon stem cells. PLoS One 2014; 9:e85469. [PMID: 24416413 PMCID: PMC3887066 DOI: 10.1371/journal.pone.0085469] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Accepted: 11/28/2013] [Indexed: 01/05/2023] Open
Abstract
Tendinopathy is characterized histopathologically by lipid accumulation and tissue calcification. Adipogenic and osteogenic differentiation of tendon stem cells (TSCs) are believed to play key roles in these processes. The major inflammatory mediator prostaglandin E2 (PGE2) has been shown to induce osteogenic differentiation of TSCs via bone morphogenetic protein-2 (BMP-2), and BMP-2 has also been implicated in adipogenic differentiation of stem cells. We therefore examined the mechanisms responsible for PGE2-induced adipogenesis in rat TSCs in vitro. Insulin-like growth factor-1 (IGF-1) mRNA and protein were significantly up-regulated in PGE2-stimulated TSCs, measured by quantitative reverse transcription-polymerase chain reaction and enzyme-linked immunosorbent assay, respectively. Incubation with specific inhibitors of cAMP, cAMP-dependent protein kinase A (PKA), and CCAAT/enhancer binding protein-δ (CEBPδ) demonstrated that IGF-1 up-regulation occurred via a cAMP/PKA/CEBPδ pathway. Furthermore, neither IGF-1 nor BMP-2 alone was able to mediate adipogenic differentiation of TSCs, but IGF-1 together with BMP-2 significantly increased adipogenesis, indicated by Oil Red O staining. Moreover, knock-down of endogenous IGF-1 and BMP2 abolished PGE2-induced adipogenic differentiation. Phosphorylation of CREB and Smad by IGF-1 and BMP-2, respectively, were required for induction of the adipogenesis-related peroxisome proliferator-activated receptor γ2 (PPARγ2) gene and for adipogenic differentiation. In conclusion, IGF-1 and BMP-2 together mediate PGE2-induced adipogenic differentiation of TSCs in vitro via a CREB- and Smad-dependent mechanism. This improved understanding of the mechanisms responsible for tendinopathies may help the development of more effective therapies.
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Affiliation(s)
- Junpeng Liu
- Department of Orthopaedics, Southwest Hospital, Third Military Medical University, Chongqing, China
| | - Lei Chen
- Department of Orthopaedics, Wuhan General Hospital of Guangzhou Military Region, Wuhan, China
| | - You zhou
- Department of Orthopaedics, Southwest Hospital, Third Military Medical University, Chongqing, China
| | - Xiangzhou Liu
- Department of Orthopaedics, Southwest Hospital, Third Military Medical University, Chongqing, China
| | - Kanglai Tang
- Department of Orthopaedics, Southwest Hospital, Third Military Medical University, Chongqing, China
- * E-mail:
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17
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Reyes AM, Jahr H, van Schie HTM, Weinans H, Zadpoor AA. Prediction of the elastic strain limit of tendons. J Mech Behav Biomed Mater 2013; 30:324-38. [PMID: 24362243 DOI: 10.1016/j.jmbbm.2013.11.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2013] [Revised: 11/20/2013] [Accepted: 11/25/2013] [Indexed: 10/26/2022]
Abstract
The elastic strain limit (ESL) of tendons is the point where maximum elastic modulus is reached, after which micro-damage starts. Study of damage progression in tendons under repetitive (fatigue) loading requires a priori knowledge about ESL. In this study, we propose three different approaches for predicting ESL. First, one single value is assumed to represent the ESL of all tendon specimens. Second, different extrapolation curves are used for extrapolating the initial part of the stress-strain curve. Third, a method based on comparing the shape of the initial part of the stress-strain curve of specimens with a database of stress-strain curves is used. A large number of porcine tendon explants (97) were tested to examine the above-mentioned approaches. The variants of the third approach yielded significantly (p<0.05) smaller error values as compared to the other approaches. The mean absolute percentage error of the best-performing variant of the shape-based comparison was between 8.14±6.44% and 9.96±9.99% depending on the size of the initial part of the stress-strain curves. Interspecies generalizability of the best performing method was also studied by applying it for prediction of the ESL of horse tendons. The ESL of horse tendons was predicted with mean absolute percentage errors ranging between 10.53±7.6% and 19.16±14.31% depending on the size of the initial part of the stress-strain curves and the type of normalization. The results of this study suggest that both ESL and the shape of stress-strain curves may be highly different between different individuals and different anatomical locations.
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Affiliation(s)
- A M Reyes
- Department of Biomechanical Engineering, Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology (TU Delft), Mekelweg 2, Delft 2628 CD, The Netherlands
| | - H Jahr
- Department of Orthopedic Surgery, University Hospital, RWTH Aachen University, Aachen, Germany
| | - H T M van Schie
- UTC Imaging, Stein, The Netherlands; Department of Physiotherapy, Faculty of Medicine, Nursing and Health Sciences, Monash University, Frankston, Australia
| | - H Weinans
- Department of Biomechanical Engineering, Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology (TU Delft), Mekelweg 2, Delft 2628 CD, The Netherlands; Department of Orthopedics and Department of Rheumatology, Utrecht University Medical Center, Utrecht, The Netherlands
| | - A A Zadpoor
- Department of Biomechanical Engineering, Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology (TU Delft), Mekelweg 2, Delft 2628 CD, The Netherlands.
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18
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Schrock P, Lüpke M, Seifert H, Staszyk C. Finite element analysis of equine incisor teeth. Part 2: Investigation of stresses and strain energy densities in the periodontal ligament and surrounding bone during tooth movement. Vet J 2013; 198:590-8. [DOI: 10.1016/j.tvjl.2013.10.010] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Revised: 09/03/2013] [Accepted: 10/07/2013] [Indexed: 11/28/2022]
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19
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Jafari L, Lemieux-Laneuville Y, Gagnon D, Langelier E. Low amplitude characterization tests conducted at regular intervals can affect tendon mechanobiological response. Ann Biomed Eng 2013; 42:589-99. [PMID: 24091466 DOI: 10.1007/s10439-013-0916-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Accepted: 09/23/2013] [Indexed: 11/24/2022]
Abstract
In bioreactor studies of tissue mechanobiology, characterizing changes in tissue quality is essential for understanding and predicting the response to mechanical stimuli. Unfortunately, current methods are often destructive and cannot be used at regular intervals on the same sample to characterize progression over time. Non-destructive methods such as low amplitude stress relaxation tests could be used, but then, the following dilemma comes into play: how can we accurately measure live tissue progression over time if the tissue is reacting to our measurement methods? In this study, we investigated the hypothesis that stress relaxation tests at physiological amplitudes conducted at regular intervals between stimulation periods do not modify tissue progression over time. Live, healthy tendons were subjected to mechanical stimuli inside a bioreactor for 3 days. The tendons were grouped based on the daily characterization protocol (24 or 0 stress relaxation tests) and their progression over time were compared. Stress relaxation tests at physiological amplitudes modified the tendon response to mechanical stimulation as observed through mechanical and histologic analyses. Possible solutions to eliminate or minimize the effect of stress relaxation tests are to use the mechanical stimuli to characterize tissue progression or to limit the number of stress relaxation tests.
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Affiliation(s)
- Leila Jafari
- Department of Mechanical Engineering, Université de Sherbrooke, Sherbrooke, QC, J1K 2R1, Canada
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20
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Shepherd JH, Screen HRC. Fatigue loading of tendon. Int J Exp Pathol 2013; 94:260-70. [PMID: 23837793 DOI: 10.1111/iep.12037] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Accepted: 06/12/2013] [Indexed: 12/28/2022] Open
Abstract
Tendon injuries, often called tendinopathies, are debilitating and painful conditions, generally considered to develop as a result of tendon overuse. The aetiology of tendinopathy remains poorly understood, and whilst tendon biopsies have provided some information concerning tendon appearance in late-stage disease, there is still little information concerning the mechanical and cellular events associated with disease initiation and progression. Investigating this in situ is challenging, and numerous models have been developed to investigate how overuse may generate tendon fatigue damage and how this may relate to tendinopathy conditions. This article aims to review these models and our current understanding of tendon fatigue damage. We review the strengths and limitations of different methodologies for characterizing tendon fatigue, considering in vitro methods that adopt both viable and non-viable samples, as well as the range of different in vivo approaches. By comparing data across model systems, we review the current understanding of fatigue damage development. Additionally, we compare these findings with data from tendinopathic tissue biopsies to provide some insights into how these models may relate to the aetiology of tendinopathy. Fatigue-induced damage consistently highlights the same microstructural, biological and mechanical changes to the tendon across all model systems and also correlates well with the findings from tendinopathic biopsy tissue. The multiple testing routes support matrix damage as an important contributor to tendinopathic conditions, but cellular responses to fatigue appear complex and often contradictory.
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Affiliation(s)
- Jennifer H Shepherd
- Institute of Bioengineering, School of Engineering and Materials Science, Queen Mary, University of London, London E1 4NS, UK.
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21
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Cordes V, Lüpke M, Gardemin M, Seifert H, Staszyk C. Periodontal biomechanics: finite element simulations of closing stroke and power stroke in equine cheek teeth. BMC Vet Res 2012; 8:60. [PMID: 22607543 PMCID: PMC3583254 DOI: 10.1186/1746-6148-8-60] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2012] [Accepted: 05/20/2012] [Indexed: 11/21/2022] Open
Abstract
Background In equine dentistry periodontal diseases, especially periapical inflammation, are
frequently occurring problems. Anachoresis is believed to be the most common cause
for the development of such disorders. Nevertheless, there is still no
substantiated explanation why settlement of pathogen microorganisms occurs in
equine periodontal tissues. It is expected that excessive strains and stresses
occurring in the periodontal ligament (PDL) during the horse’s chewing cycle
might be a predisposing factor. In this study this assumption was examined by
finite element (FE) analyses on virtual 3-D models of equine maxillary and
mandibular cheek teeth, established on the basis of μCT datasets.
Calculations were conducted both under conditions of closing and power stroke. Results Results showed a uniform distribution of low stresses and strain energy density
(SED) during closing stroke, whereas during power stroke an occurrence of high
stresses and SED could be observed in the PDL near the alveolar crest and in
periapical regions. Conclusion The concentration of forces during power stroke in these specific areas of the PDL
may cause local tissue necrosis and inflammation and thus establish a suitable
environment for the settlement of microorganisms.
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Affiliation(s)
- Vanessa Cordes
- Institute of Anatomy, University of Veterinary Medicine Hannover, Bischofsholer Damm 15, Hannover, D-30173, Germany.
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22
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Navalho M, Resende C, Rodrigues AM, Ramos F, Gaspar A, Pereira da Silva JA, Fonseca JE, Campos J, Canhão H. Bilateral MR imaging of the hand and wrist in early and very early inflammatory arthritis: tenosynovitis is associated with progression to rheumatoid arthritis. Radiology 2012; 264:823-33. [PMID: 22723498 DOI: 10.1148/radiol.12112513] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
PURPOSE To identify bilateral hand and wrist findings of synovial inflammation associated with progression to rheumatoid arthritis (RA) in very-early-RA cohort (VERA) (duration, <3 months) and early-RA cohort (ERA) (duration, <12 but >3 months), to test tenosynovitis as a magnetic resonance (MR) imaging additional parameter for improving diagnostic accuracy of the 2010 American College of Rheumatology/European League Against Rheumatism (ACR/EULAR) RA classification criteria, and to evaluate the symmetry of joint and tendon involvement. MATERIALS AND METHODS With institutional review board approval and informed consent, 32 women and three men (mean age, 45 years) with untreated recent-onset inflammatory arthritis participated in this prospective study and underwent MR imaging of both wrists and hands. After 12-month follow-up, 25 patients fulfilled the criteria for RA (10 VERA and 15 ERA patients). Ten patients did not fulfill the criteria for RA (non-RA [control] group). Possible associations between synovitis for each joint and tendon and RA diagnosis at 12 months were tested (univariate logistic regression analysis). Diagnostic performance of the ACR/EULAR RA classification criteria was evaluated (receiver operating characteristic curve analysis). Asymmetry prevalence (all joints and tendons in the analysis) was calculated. RESULTS Tenosynovitis of the extensor carpi ulnaris (odds ratio, 3.21) and flexor tendons of the second finger (odds ratio, 14.61) in VERA group and synovitis of the radioulnar joint (odds ratio, 8.79) and tenosynovitis of flexor tendons of the second finger (odds ratio, 9.60) in ERA group were significantly associated with progression to RA (P < .05). Consideration of tenosynovitis improved areas under the receiver operating characteristic curve of ACR/EULAR criteria performance for the diagnosis of RA from 0.942 (P < .0001; sensitivity, 52%; specificity, 100%) to 0.972 (P < .0001; sensitivity, 76%; specificity, 100%), with cutoff score of 6 or greater. Asymmetry was found in 80.0% (62 of 77) (VERA patients) and 69.3% (106 of 153) (ERA patients) of joint or tendon pairs (P < .05). CONCLUSION Tenosynovitis is an imaging finding in early RA, and its inclusion as a scoring criterion might contribute for a better diagnostic performance of the 2010 ACR/EULAR classification; early RA is an asymmetric disease.
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Affiliation(s)
- Márcio Navalho
- Rheumatology Research Unit, Instituto de Medicina Molecular, Faculdade de Medicina da Universidade de Lisboa, Av Prof Egas Moniz, 1649-028 Lisbon, Portugal.
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23
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Eliasson P, Andersson T, Aspenberg P. Influence of a single loading episode on gene expression in healing rat Achilles tendons. J Appl Physiol (1985) 2011; 112:279-88. [PMID: 21998267 DOI: 10.1152/japplphysiol.00858.2011] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Mechanical loading stimulates tendon healing via mechanisms that are largely unknown. Genes will be differently regulated in loaded healing tendons, compared with unloaded, just because of the fact that healing processes have been changed. To avoid such secondary effects and study the effect of loading per se, we therefore studied the gene expression response shortly after a single loading episode in otherwise unloaded healing tendons. The Achilles tendon was transected in 30 tail-suspended rats. The animals were let down from the suspension to load their tendons on a treadmill for 30 min once, 5 days after tendon transection. Gene expression was studied by Affymetrix microarray before and 3, 12, 24, and 48 h after loading. The strongest response in gene expression was seen 3 h after loading, when 150 genes were up- or downregulated (fold change ≥2, P ≤ 0.05). Twelve hours after loading, only three genes were upregulated, whereas 38 were downregulated. Fewer than seven genes were regulated after 24 and 48 h. Genes involved in the inflammatory response were strongly regulated at 3 and 12 h after loading; this included upregulation of iNOS, PGE synthase, and IL-1β. Also genes involved in wound healing/coagulation, angiogenesis, and production of reactive oxygen species were strongly regulated by loading. Microarray results were confirmed for 16 selected genes in a repeat experiment (N = 30 rats) using real-time PCR. It was also confirmed that a single loading episode on day 5 increased the strength of the healing tendon on day 12. In conclusion, the fact that there were hardly any regulated genes 24 h after loading suggests that optimal stimulation of healing requires a mechanical loading stimulus every day.
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Affiliation(s)
- Pernilla Eliasson
- Orthopaedics, Department of Clinical and Experimental Medicine, Faculty of Health Science, Linköping University, Linköping, Sweden.
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24
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Green ME, Goforth PB, Satin LS, Love BJ. An integrated instrument for rapidly deforming living cells using rapid pressure pulses and simultaneously monitoring applied strain in near real time. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2010; 81:125102. [PMID: 21198046 PMCID: PMC3017568 DOI: 10.1063/1.3520135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2010] [Accepted: 11/03/2010] [Indexed: 05/30/2023]
Abstract
Because many types of living cells are sensitive to applied strain, different in vitro models have been designed to elucidate the cellular and subcellular processes that respond to mechanical deformation at both the cell and tissue level. Our focus was to improve upon an already established strain system to make it capable of independently monitoring the deflection and applied pressure delivered to specific wells of a commercially available, deformable multiwell culture plate. To accomplish this, we devised a custom frame that was capable of mounting deformable 6 or 24 well plates, a pressurization system that could load wells within the plates, and a camera-based imaging system which was capable of capturing strain responses at a sufficiently high frame rate. The system used a user defined program constructed in Labview(®) to trigger plate pressurization while simultaneously allowing the deflection of the silicone elastomeric plate bottoms to be imaged in near real time. With this system, up to six wells could be pulsed simultaneously using compressed air or nitrogen. Digital image capture allowed near-real time monitoring of applied strain, strain rate, and the cell loading profiles. Although our ultimate goal is to determine how different strain rates applied to neurons modulates their intrinsic biochemical cascades, the same platform technology could be readily applied to other systems. Combining commercially available, deformable multiwell plates with a simple instrument having the monitoring capabilities described here should permit near real time calculations of stretch-induced membrane strain in multiple wells in real time for a wide variety of applications, including high throughput drug screening.
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Affiliation(s)
- M E Green
- Department of Materials Science and Engineering, The University of Michigan, Ann Arbor, Michigan 48109, USA
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25
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Christensen B, Dandanell S, Kjaer M, Langberg H. Effect of anti-inflammatory medication on the running-induced rise in patella tendon collagen synthesis in humans. J Appl Physiol (1985) 2010; 110:137-41. [PMID: 21030675 DOI: 10.1152/japplphysiol.00942.2010] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
NSAIDs are widely used in the treatment of inflammatory diseases as well as of tendon diseases associated with pain in sports and labor. However, the effect of NSAID intake, and thus blockade of PGE(2) production, on the tendon tissue adaptation is unknown. The purpose of the present study was to elucidate the possible effects of NSAID intake on healthy tendon collagen turnover in relation to a strenuous bout of endurance exercise. Fifteen healthy young men were randomly assigned into two experimental groups, with one group receiving indomethacin (oral 2 × 100 mg Confortid daily for 7 days; NSAID; n = 7) and a placebo group (n = 8). Both groups were exposed to a prolonged bout of running (36 km). The collagen synthesis NH₂-terminal propeptide of type I (PINP) and PGE₂ concentrations were measured before and 72 h following the run in the patella tendon by microdialysis. The peritendinous concentrations of PINP increased significantly in the placebo group as a result of the run, as shown previously. PGE₂ levels were significantly decreased 72 h after the run compared with basal levels in the subjects treated with NSAID and unchanged in the placebo group. The NSAID intake abolished the adaptive increase in collagen synthesis in the patella tendon found in the placebo group in response to the prolonged exercise (P < 0.05). The present study demonstrates that intake of NSAID decreased interstitial PGE₂ and abolished the exercise-induced adaptive increase in collagen synthesis in human tendons.
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Affiliation(s)
- Britt Christensen
- Institute of Sports Medicine Copenhagen, Bispebjerg Hospital, and Center of Healthy Aging, University of Copenhagen, Copenhagen, Denmark
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26
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Arampatzis A, Peper A, Bierbaum S, Albracht K. Plasticity of human Achilles tendon mechanical and morphological properties in response to cyclic strain. J Biomech 2010; 43:3073-9. [PMID: 20863501 DOI: 10.1016/j.jbiomech.2010.08.014] [Citation(s) in RCA: 143] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2010] [Revised: 07/13/2010] [Accepted: 08/13/2010] [Indexed: 11/27/2022]
Abstract
The purpose of the current study in combination with our previous published data (Arampatzis et al., 2007) was to examine the effects of a controlled modulation of strain magnitude and strain frequency applied to the Achilles tendon on the plasticity of tendon mechanical and morphological properties. Eleven male adults (23.9 ± 2.2 yr) participated in the study. The participants exercised one leg at low magnitude tendon strain (2.97 ± 0.47%), and the other leg at high tendon strain magnitude (4.72 ± 1.08%) of similar frequency (0.5 Hz, 1s loading, 1s relaxation) and exercise volume (integral of the plantar flexion moment over time) for 14 weeks, 4 days per week, 5 sets per session. The exercise volume was similar to the intervention of our earlier study (0.17 Hz frequency; 3s loading, 3s relaxation) allowing a direct comparison of the results. Before and after the intervention ankle joint moment has been measured by a dynamometer, tendon-aponeurosis elongation by ultrasound and cross-sectional area of the Achilles tendon by magnet resonance images (MRI). We found a decrease in strain at a given tendon force, an increase in tendon-aponeurosis stiffness and tendon elastic modulus of the Achilles tendon only in the leg exercised at high strain magnitude. The cross-sectional area (CSA) of the Achilles tendon did not show any statistically significant (P > 0.05) differences to the pre-exercise values in both legs. The results indicate a superior improvement in tendon properties (stiffness, elastic modulus and CSA) at the low frequency (0.17 Hz) compared to the high strain frequency (0.5 Hz) protocol. These findings provide evidence that the strain magnitude applied to the Achilles tendon should exceed the value, which occurs during habitual activities to trigger adaptational effects and that higher tendon strain duration per contraction leads to superior tendon adaptational responses.
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Affiliation(s)
- Adamantios Arampatzis
- Humboldt-University Berlin, Department of Training and Movement Sciences, Berlin, Germany.
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27
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Devkota AC, Weinhold PS. Prostaglandin E(2), collagenase, and cell death responses depend on cyclical load magnitude in an explant model of tendinopathy. Connect Tissue Res 2010; 51:306-13. [PMID: 20175712 DOI: 10.3109/03008200903318261] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Tendinopathy is a significant clinical problem that can result from repetitive activity. While the precise etiology of this condition remains unclear, the cellular response to cyclical loading is believed to have a contributory role to the pathology of tendinopathy. This study examined the short-term biochemical response of avian flexor digitorum profundus tendon to repetitive cyclic loadings of varying magnitude. An in vitro tendon explant model was utilized to apply four levels of haversine tensile stress (peak stress of 0, 3, 12, and 18 MPa) at 1.0 Hz, 8 hr/day for 3 days. The 12 and 18 MPa levels were known to cause significant mechanical damage based on previous work. Tissue media was recovered and analyzed for prostaglandin E(2) (PGE(2)), lactate dehydrogenase (LDH, measure of cell death), and collagenase levels. Tissue samples were recovered and analyzed for cell viability, total collagen, and sulfated glycosaminoglycan content. Collagenase, LDH, and PGE(2) levels were found to be influenced by loading magnitude (p < 0.05) with higher levels being present at higher load magnitudes. Varying cyclical load magnitude caused minimal compositional changes as collagen content and glycosaminoglycan did not change. These results indicate that elevated cyclical mechanical loading of tendon quickly results in altered biochemical tissue responses indicative of tissue injury. More sustained cyclical loading over time may be required for these initial responses to induce more dramatic tissue changes as observed in clinical tendinopathy.
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Affiliation(s)
- Aaditya C Devkota
- Department of Orthopaedics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7546, USA
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Cousineau-Pelletier P, Langelier E. Relative contributions of mechanical degradation, enzymatic degradation, and repair of the extracellular matrix on the response of tendons when subjected to under- and over- mechanical stimulations in vitro. J Orthop Res 2010; 28:204-10. [PMID: 19725106 DOI: 10.1002/jor.20982] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Tendon response to mechanical loading results in either homeostasis, improvement, or degeneration of tissue condition. In an effort to better understand the development of tendinopathies, this study investigated the mechanical and structural responses of tendons subjected to under- and over-stimulations (1.2% and 1.8% strain respectively, 1 Hz). The objective was to examine three sub-processes of tendon response: mechanical degradation, enzymatic degradation, and repair of the extracellular matrix. We subjected rat tail tendons to a 10-day stimulation protocol with four periods of 6 h each day: 30 min of stimulation and 5 h 30 min of rest. To investigate the contribution of the three sub-processes, we controlled the contribution of the cells through variations in the nutrient and protease inhibitor content in the in vitro solutions. Using nondestructive cyclic tests, we evaluated the daily changes in the peak stress. To assess structural changes, we carried out microscopic analyses at the end of the study period. We observed that the relative contributions of the sub-processes differed according to the stimulation amplitude. With over-stimulation of tendons immersed in DMEM, we succeeded in reducing enzymatic degradation and increasing peak stress. In under-stimulation, the addition of protease inhibitors was required to obtain the same result.
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Affiliation(s)
- Paule Cousineau-Pelletier
- PERSEUS, Département de Génie Mécanique, Université de Sherbrooke, Sherbrooke, Québec J1K 2R1, Canada
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29
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Zhang J, Wang JHC. Production of PGE(2) increases in tendons subjected to repetitive mechanical loading and induces differentiation of tendon stem cells into non-tenocytes. J Orthop Res 2010; 28:198-203. [PMID: 19688869 DOI: 10.1002/jor.20962] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Whether tendon inflammation is involved in the development of tendinopathy or degenerative changes of the tendon remains a matter of debate. We explored this question by performing animal and cell culture experiments to determine the production and effects of PGE(2), a major inflammatory mediator in tendons. Mouse tendons were subjected to repetitive mechanical loading via treadmill running, and the effect of PGE(2) on proliferation and differentiation of tendon stem cells (TSCs) was assessed in vitro. Compared to levels in cage control mice, PGE(2) levels in mouse patellar and Achilles tendons were markedly increased in response to a bout of rigorous treadmill running. PGE(2) treatment of TSCs in culture decreased cell proliferation and induced both adipogenesis and osteogenesis of TSCs, as evidenced by accumulation of lipid droplets and calcium deposits, respectively. Effects of PGE(2) on both TSC proliferation and differentiation were apparently PGE(2)-dose-dependent. These findings suggest that high levels of PGE(2), which are present in tendons subjected to repetitive mechanical loading conditions in vivo as shown in this study, may result in degenerative changes of the tendon by decreasing proliferation of TSCs in tendons and also inducing differentiation of TSCs into adipocytes and osteocytes. The consequences of this PGE(2) effect on TSCs is the reduction of the pool of tenocytes for repair of tendons injured by mechanical loading, and production of fatty and calcified tissues within the tendon, often seen at the later stages of tendinopathy.
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Affiliation(s)
- Jianying Zhang
- MechanoBiology Laboratory, Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania 15213, USA.
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Benhardt HA, Cosgriff-Hernandez EM. The Role of Mechanical Loading in Ligament Tissue Engineering. TISSUE ENGINEERING PART B-REVIEWS 2009; 15:467-75. [DOI: 10.1089/ten.teb.2008.0687] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Hugh A. Benhardt
- Department of Biomedical Engineering, Texas A&M University, College Station, Texas
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31
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Or M, Kimmel E. Modeling linear vibration of cell nucleus in low intensity ultrasound field. ULTRASOUND IN MEDICINE & BIOLOGY 2009; 35:1015-1025. [PMID: 19376638 DOI: 10.1016/j.ultrasmedbio.2008.11.011] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2008] [Revised: 10/27/2008] [Accepted: 11/14/2008] [Indexed: 05/27/2023]
Abstract
Therapeutic ultrasound of low to medium intensity is known to induce alterations in structure and functioning of cells and tissues, both in vivo and in vitro. Such effects, including excitation or inhibition of action potentials, enhanced angiogenesis rate, increased membrane permeability and changes in molecular expression, cannot be attributed in many cases to rising temperatures or the presence of gas bubbles. This study attempts to find a possible alternative explanation for the cases where neither thermal effects nor cavitation mechanisms count. We focus our attention on the complex and dense structure of cell cytoplasm, looking for periodic separating forces and relative motion between intracellular elements, such as the nucleus, and the structure in which they are embedded. It is hypothesized that relative oscillatory displacements between intracellular elements of different densities might appear in cells in response to low intensity therapeutic ultrasound (LITUS). Those displacements might induce alterations in cell structure and functioning. A linear model is constructed and solved for a spherical object, representing a typical organelle such as the nucleus, within a homogenous viscoelastic medium that vibrates uniformly. The structure in which the object is embedded is described by four different rheologic models, including viscous fluid, elastic solid, and Voigt and Maxwell viscoelastic constructs. It is found that cyclic intracellular displacements comparable with and even larger than the mean thermal fluctuations may be obtained due to LITUS irradiation in conditions where the relative motion of organelles is dominated by elastic response, or where the effective viscosity of the cytoplasm is low. Resonance frequency at which intracellular vibration of maximal amplitude is obtained is found to lie within the low LITUS frequency range, i.e., tens to hundreds of kHz. Local intracellular strain on the order of 0.5% is found for 1 microm organelle in 10 microm cell under typical LITUS settings. It is suggested that fatigue-like, cumulative effect underlie the transfer of the intracellular strain into biologic alterations.
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Affiliation(s)
- Meir Or
- Biomedical Engineering Department, Technion, Haifa, Israel.
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Maeda E, Shelton JC, Bader DL, Lee DA. Differential regulation of gene expression in isolated tendon fascicles exposed to cyclic tensile strain in vitro. J Appl Physiol (1985) 2008; 106:506-12. [PMID: 19036888 DOI: 10.1152/japplphysiol.90981.2008] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Mechanical stimulus is a regulator of tenocyte metabolism. The present study investigated temporal regulation of the expression of selected genes by tenocytes in isolated fascicles subjected to tensile strain in vitro. Cyclic tensile strain with a 3% amplitude superimposed on a 2% static strain was provided for 10 min, followed by either an unstrained period or continuous cyclic strain until the end of a 24-h incubation period. mRNA expression of selected anabolic and catabolic genes were evaluated with quantitative PCR at 10 min, 1 h, 6 h, and 24 h. The application of 6-h cyclic strain significantly upregulated type III collagen mRNA expression in strained fascicles compared with unstrained controls, but no alterations were observed in mRNA expression of type I collagen and biglycan. Significant downregulation in the expression of the decorin core protein was observed in fascicles subjected to 24-h cyclic strain. MMP3 and MMP13 expression levels were upregulated by the application of 10 min of cyclic strain, followed by a progressive downregulation until the end of the incubation period in both the absence and the presence of the continuing cyclic strain. Accordingly, alterations in the expression of anabolic genes were limited to the upregulation of type III collagen by prolonged exposure to cyclic strain, whereas catabolic genes were upregulated by a small number of strain cycles and downregulated by a prolonged cyclic strain. These findings demonstrate distinctive patterns of mechanoregulation for anabolic and catabolic genes and help our understanding of tenocyte response to mechanical stimulation.
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Affiliation(s)
- Eijiro Maeda
- School of Engineering and Materials Science, Queen Mary, Uniersity of London, London, E1 4NS, UK
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Coordinate regulation of IL-1beta and MMP-13 in rat tendons following subrupture fatigue damage. Clin Orthop Relat Res 2008; 466:1555-61. [PMID: 18470577 PMCID: PMC2505236 DOI: 10.1007/s11999-008-0278-4] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2007] [Accepted: 04/16/2008] [Indexed: 01/31/2023]
Abstract
Mechanical overloading is a major causative factor of tendinopathy; however, its underlying mechanisms are unclear. We hypothesized mechanical overloading would damage tendons and alter genes associated with tendinopathy in a load-dependent manner. To test this hypothesis, we fatigue loaded rat patellar tendons in vivo and measured expression of the matrix-degrading enzyme MMP-13 and the inflammatory cytokine IL-1beta. We also examined these responses in cultured tenocytes exposed to intermittent hydrostatic pressure in vitro. Additionally, we hypothesized load-induced changes in tenocyte MMP-13 expression would be dependent on expression of IL-1beta. In vivo fatigue loading at 1.7% strain caused overt microstructural damage and upregulated expression of MMP-13 and IL-1beta, while 0.6% strain produced only minor changes in matrix microstructure and downregulated expression of both MMP-13 and IL-1beta. Loading of cultured tenocytes at 2.5 and 7.5 MPa produced comparable changes in expression to those of in vivo tendon loading. Blocking IL-1beta expression with siRNA suppressed load-induced both MMP-13 mRNA expression and activity. The data suggest fatigue loading alters expression of MMP-13 and IL-1beta in tendons in vivo and tenocytes in vitro in a load-dependent manner. The data also suggest MMP-13 is regulated by both IL-1beta-dependent and IL-1beta-independent pathways.
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