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Wang J, Maeda E, Tsujimura Y, Abe T, Kiyonari H, Kitaguchi T, Yokota H, Matsumoto T. In situ FRET measurement of cellular tension using conventional confocal laser microscopy in newly established reporter mice expressing actinin tension sensor. Sci Rep 2023; 13:22729. [PMID: 38123655 PMCID: PMC10733408 DOI: 10.1038/s41598-023-50142-z] [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: 09/07/2023] [Accepted: 12/15/2023] [Indexed: 12/23/2023] Open
Abstract
FRET-based sensors are utilized for real-time measurements of cellular tension. However, transfection of the sensor gene shows low efficacy and is only effective for a short period. Reporter mice expressing such sensors have been developed, but sensor fluorescence has not been measured successfully using conventional confocal microscopy. Therefore, methods for spatiotemporal measurement of cellular tension in vivo or ex vivo are still limited. We established a reporter mouse line expressing FRET-based actinin tension sensors consisting of EGFP as the donor and mCherry as the acceptor and whose FRET ratio change is observable with confocal microscopy. Tension-induced changes in FRET signals were monitored in the aorta and tail tendon fascicles, as well as aortic smooth muscle cells isolated from these mice. The pattern of FRET changes was distinctive, depending on tissue type. Indeed, aortic smooth muscle cells exhibit different sensitivity to macroscopic tensile strain in situ and in an isolated state. This mouse strain will enable novel types of biomechanical investigations of cell functions in important physiological events.
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Affiliation(s)
- Junfeng Wang
- Biomechanics Laboratory, Department of Mechanical Systems Engineering, Graduate School of Engineering, Nagoya University, Furo-Cho, Chikusa-Ku, Nagoya, Aichi, 464-8603, Japan
| | - Eijiro Maeda
- Biomechanics Laboratory, Department of Mechanical Systems Engineering, Graduate School of Engineering, Nagoya University, Furo-Cho, Chikusa-Ku, Nagoya, Aichi, 464-8603, Japan
| | - Yuki Tsujimura
- RIKEN Center for Advanced Photonics, RIKEN, Wako, Saitama, Japan
| | - Takaya Abe
- Laboratory for Animal Resources and Genetic Engineering, RIKEN Center for Biosystems Dynamics Research, Kobe, Hyogo, Japan
| | - Hiroshi Kiyonari
- Laboratory for Animal Resources and Genetic Engineering, RIKEN Center for Biosystems Dynamics Research, Kobe, Hyogo, Japan
| | - Tetsuya Kitaguchi
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Kanagawa, Japan
| | - Hideo Yokota
- RIKEN Center for Advanced Photonics, RIKEN, Wako, Saitama, Japan
| | - Takeo Matsumoto
- Biomechanics Laboratory, Department of Mechanical Systems Engineering, Graduate School of Engineering, Nagoya University, Furo-Cho, Chikusa-Ku, Nagoya, Aichi, 464-8603, Japan.
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2
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Chatterjee M, Evans MK, Bell R, Nguyen PK, Kamalitdinov TB, Korntner S, Kuo CK, Dyment NA, Andarawis-Puri N. Histological and immunohistochemical guide to tendon tissue. J Orthop Res 2023; 41:2114-2132. [PMID: 37321983 DOI: 10.1002/jor.25645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Revised: 06/02/2023] [Accepted: 06/11/2023] [Indexed: 06/17/2023]
Abstract
Tendons are unique dense connective tissues with discrete zones having specific structure and function. They are juxtaposed with other tissues (e.g., bone, muscle, and fat) with different compositional, structural, and mechanical properties. Additionally, tendon properties change drastically with growth and development, disease, aging, and injury. Consequently, there are unique challenges to performing high quality histological assessment of this tissue. To address this need, histological assessment was one of the breakout session topics at the 2022 Orthopaedic Research Society (ORS) Tendon Conference hosted at the University of Pennsylvania. The purpose of the breakout session was to discuss needs from members of the ORS Tendon Section related to histological procedures, data presentation, knowledge dissemination, and guidelines for future work. Therefore, this review provides a brief overview of the outcomes of this discussion and provides a set of guidelines, based on the perspectives from our laboratories, for histological assessment to assist researchers in their quest to utilize these techniques to enhance the outcomes and interpretations of their studies.
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Affiliation(s)
- Monideepa Chatterjee
- Nancy E. and Peter C. Meinig School of Biomedical Engineering, Cornell University, Ithaca, New York, USA
| | - Mary K Evans
- Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Rebecca Bell
- Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, New York, USA
| | - Phong K Nguyen
- Department of Biomedical Engineering, University of Rochester, Rochester, New York, USA
| | - Timur B Kamalitdinov
- Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Stefanie Korntner
- Fischell Department of Bioengineering, University of Maryland, College Park, Maryland, USA
| | - Catherine K Kuo
- Department of Biomedical Engineering, University of Rochester, Rochester, New York, USA
- Fischell Department of Bioengineering, University of Maryland, College Park, Maryland, USA
- Center for Musculoskeletal Research, University of Rochester Medical Center, Rochester, New York, USA
- Department of Orthopaedics, University of Maryland Medical Center, Baltimore, Maryland, USA
| | - Nathaniel A Dyment
- Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Nelly Andarawis-Puri
- Nancy E. and Peter C. Meinig School of Biomedical Engineering, Cornell University, Ithaca, New York, USA
- Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, New York, USA
- Hospital for Special Surgery, New York, New York, USA
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3
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Inguito KL, Schofield MM, Faghri AD, Bloom ET, Heino M, West VC, Ebron KMM, Elliott DM, Parreno J. Stress deprivation of tendon explants or Tpm3.1 inhibition in tendon cells reduces F-actin to promote a tendinosis-like phenotype. Mol Biol Cell 2022; 33:ar141. [PMID: 36129771 PMCID: PMC9727789 DOI: 10.1091/mbc.e22-02-0067] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Actin is a central mediator between mechanical force and cellular phenotype. In tendons, it is speculated that mechanical stress deprivation regulates gene expression by reducing filamentous (F)-actin. However, the mechanisms regulating tenocyte F-actin remain unclear. Tropomyosins (Tpms) are master regulators of F-actin. There are more than 40 Tpm isoforms, each having the unique capability to stabilize F-actin subpopulations. We investigated F-actin polymerization in stress-deprived tendons and tested the hypothesis that stress fiber-associated Tpm(s) stabilize F-actin to regulate cellular phenotype. Stress deprivation of mouse tail tendon down-regulated tenogenic and up-regulated protease (matrix metalloproteinase-3) mRNA levels. Concomitant with mRNA modulation were increases in G/F-actin, confirming reduced F-actin by tendon stress deprivation. To investigate the molecular regulation of F-actin, we identified that tail, Achilles, and plantaris tendons express three isoforms in common: Tpm1.6, 3.1, and 4.2. Tpm3.1 associates with F-actin in native and primary tenocytes. Tpm3.1 inhibition reduces F-actin, leading to decreases in tenogenic expression, increases in chondrogenic expression, and enhancement of protease expression in mouse and human tenocytes. These expression changes by Tpm3.1 inhibition are consistent with tendinosis progression. A further understanding of F-actin regulation in musculoskeletal cells could lead to new therapeutic interventions to prevent alterations in cellular phenotype during disease progression.
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Affiliation(s)
- Kameron L. Inguito
- Departments of Biological Sciences, University of Delaware, Newark, DE 19716
| | - Mandy M. Schofield
- Departments of Biological Sciences, University of Delaware, Newark, DE 19716
| | - Arya D. Faghri
- Departments of Biological Sciences, University of Delaware, Newark, DE 19716
| | - Ellen T. Bloom
- Biomedical Engineering, University of Delaware, Newark, DE 19716
| | - Marissa Heino
- Departments of Biological Sciences, University of Delaware, Newark, DE 19716,Biomedical Engineering, University of Delaware, Newark, DE 19716
| | - Valerie C. West
- Biomedical Engineering, University of Delaware, Newark, DE 19716
| | | | - Dawn M. Elliott
- Biomedical Engineering, University of Delaware, Newark, DE 19716
| | - Justin Parreno
- Departments of Biological Sciences, University of Delaware, Newark, DE 19716,Biomedical Engineering, University of Delaware, Newark, DE 19716,*Address correspondence to: Justin Parreno ()
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Chatterjee M, Muljadi PM, Andarawis-Puri N. The role of the tendon ECM in mechanotransduction: disruption and repair following overuse. Connect Tissue Res 2022; 63:28-42. [PMID: 34030531 DOI: 10.1080/03008207.2021.1925663] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Purpose: Tendon overuse injuries are prevalent conditions with limited therapeutic options to halt disease progression. The specialized extracellular matrix (ECM) both enables joint function and mediates mechanical signals to tendon cells, driving biological responses to exercise or injury. With overuse, tendon ECM composition and structure changes at multiple scales, disrupting mechanotransduction and resulting in inadequate repair and disease progression. This review highlights the multiscale ECM changes that occur with tendon overuse and corresponding effects on cell-matrix interactions and cellular response to load.Results: Different functional joint requirements and tendon types experience a wide range of loading profiles, creating varied downstream mechanical stimuli. Distinct ECM structure and mechanical properties within the fascicle matrix, interfascicle matrix, and enthesis and their varied disruption with overuse are considered. The pericellular matrix (PCM) comprising the microscale tendon cell environment has a unique composition that changes with overuse injury and exercise, suggesting an important role in mechanotransduction and promoting repair. Cell-matrix interactions are mediated by structures including cilia, integrins, connexins and cytoskeleton that signal downstream homeostasis, adaptation, or repair. ECM disruption with tendon overuse may cause altered mechanical loading and cell-matrix interactions, resulting in mechanobiological understimulation, apoptosis, and ineffective repair. Current interventions to promote repair of tendon overuse injuries including exercise, targeting cell signaling, and modulating inflammation are considered.Conclusion: Future therapeutics should be assessed with regard of their effects on multiscale mechanotransduction in addition to joint function, with consideration of the central role of ECM.
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Affiliation(s)
- Monideepa Chatterjee
- Nancy E. And Peter C. Meinig School of Biomedical Engineering, Cornell University, Ithaca, New York, USA
| | - Patrick M Muljadi
- Nancy E. And Peter C. Meinig School of Biomedical Engineering, Cornell University, Ithaca, New York, USA
| | - Nelly Andarawis-Puri
- Nancy E. And Peter C. Meinig School of Biomedical Engineering, Cornell University, Ithaca, New York, USA.,Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, New York, USA.,Hospital for Special Surgery, New York, New York, USA
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5
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Egerbacher M, Gardner K, Caballero O, Hlavaty J, Schlosser S, Arnoczky SP, Lavagnino M. Stress-deprivation induces an up-regulation of versican and connexin-43 mRNA and protein synthesis and increased ADAMTS-1 production in tendon cells in situ. Connect Tissue Res 2022; 63:43-52. [PMID: 33467936 DOI: 10.1080/03008207.2021.1873302] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Purpose: The proper function of the tenocyte network depends on cell-matrix as well as intercellular communication that is mechanosensitive. Building on the concept that the etiopathogenic stimulus for tendon degeneration is the catabolic response of tendon cells to mechanobiologic under-stimulation, we studied the pericellular matrix rich in versican and its predominant proteolytic enzyme ADAMTS-1, as well as Connexin-43 (Cx43), a major gap junction forming protein in tendons, in stress-deprived rat tail tendon fascicles (RTTfs).Materials and Methods: RTTfs were stress-deprived for up to 7 days under tissue culture conditions. RT-qPCR was used to measure mRNA expression of versican, ADAMTS-1, and Cx43. Protein synthesis was determined using Western blotting and immunohistochemistry.Results: Stress-deprivation (SD) caused a statistically significant up-regulation of versican, ADAMTS-1, and Cx43 mRNA expression that was persistent over the 7-day test period. Western blot analysis and immunohistochemical assessment of protein synthesis revealed a marked increase of the respective proteins with SD. Inhibition of proteolytic enzyme activity with ilomastat prevented the increased versican degradation and Cx43 synthesis in 3 days stress-deprived tendons when compared with non-treated, stress-deprived tendons.Conclusion: In the absence of mechanobiological signaling the immediate pericellular matrix is modulated as tendon cells up-regulate their production of ADAMTS-1, and versican with subsequent proteoglycan degradation potentially leading to cell signaling cues increasing Cx43 gap junctional protein. The results also provide further support for the hypothesis that the cellular changes associated with tendinopathy are a result of decreased mechanobiological signaling and a loss of homeostatic cytoskeletal tension.
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Affiliation(s)
- Monika Egerbacher
- Histology & Embryology, Department of Pathobiology, University of Veterinary Medicine, Vienna, Austria
| | - Keri Gardner
- Laboratory for Comparative Orthopaedic Research, Michigan State University, East Lansing, MI, USA
| | - Oscar Caballero
- Laboratory for Comparative Orthopaedic Research, Michigan State University, East Lansing, MI, USA
| | - Juraj Hlavaty
- Histology & Embryology, Department of Pathobiology, University of Veterinary Medicine, Vienna, Austria
| | - Sarah Schlosser
- VetCORE Facility for Research, University of Veterinary Medicine, Vienna, Austria
| | - Steven P Arnoczky
- Laboratory for Comparative Orthopaedic Research, Michigan State University, East Lansing, MI, USA
| | - Michael Lavagnino
- Laboratory for Comparative Orthopaedic Research, Michigan State University, East Lansing, MI, USA.,Department of Mechanical Engineering, Michigan State University, East Lansing, MI, USA
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6
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Al Makhzoomi AK, Kirk TB, Dye DE, Allison GT. Contribution of glycosaminoglycans to the structural and mechanical properties of tendons - A multiscale study. J Biomech 2021; 128:110796. [PMID: 34649066 DOI: 10.1016/j.jbiomech.2021.110796] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Revised: 09/17/2021] [Accepted: 10/03/2021] [Indexed: 11/18/2022]
Abstract
Tendinopathy of the Achilles tendon contributes to a large range of disorders, including mechanical damage and degenerative diseases. Glycosaminoglycans (GAGs), are thought to play a role in the mechanical strength of tendons by forming cross-links between collagen molecules and allowing the transmission of forces between fibrils. This study assessed the response of GAG-depleted tendons to damage induced by fatigue loading, investigating the mechanical damage (stiffness, hysteresis and maximum load), macrostructural changes (tenocyte morphology, fiber anisotropy and waviness) assessed by confocal imaging and nanostructural changes (fibril D-periodicity length) within the same non-viable intact tendons. Changes in fiber waviness and tenocyte shape are strongly correlated to mechanical and nano-structural (D-periodicity elongation) properties in both Control and GAG-depleted tendons. This study supports firstly, the vital role GAGs play as mechanical connectors facilitating the load transfer between the fibrils and their hydrophilic role in facilitating fibril sliding. Secondly, that observed changes in tenocyte shape and fiber waviness correlate with tendon stiffness and other mechanical profiles.
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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
| | - Danielle E Dye
- Curtin Medical School, Faculty of Health Sciences, Curtin University, Perth, Western Australia, Australia
| | - Garry T Allison
- Research Office, Curtin University, Perth, Western Australia, Australia
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7
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Microscopic characterisation of local strain field in healing tissue in the central third defect of mouse patellar tendon at early-phase of healing. J Mech Behav Biomed Mater 2021; 123:104702. [PMID: 34365097 DOI: 10.1016/j.jmbbm.2021.104702] [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: 04/14/2021] [Revised: 06/26/2021] [Accepted: 07/03/2021] [Indexed: 11/20/2022]
Abstract
Tendons exhibit a hierarchical collagen structure, wherein higher-level components, such as collagen fibres and fascicles, are elongated, slid, and rotated during macroscopic stretching. These mechanical behaviours of collagen fibres play important roles in stimulating tenocytes, imposing stretching, compression, and shear deformation. It was hypothesised that a lack of local fibre behaviours in healing tendon tissue may result in a limited application of mechanical stimuli to cells within the tissue, leading to incomplete recovery of tissue structure and functions in regenerated tendons. Therefore, the present study aimed to measure the microscopic strain field in the healing tendon tissue. A central third defect was created in the patellar tendon of mice, and the regenerated tissue in the defect was examined by tensile testing, collagen fibre analysis, and local strain measurement using confocal microscopy at 3 and 6 weeks after surgery. Healing tissue at 3 weeks exhibited a significantly lower strength and disorganised collagen fibre structure compared with the normal tendon. These characteristics at 6 weeks remained significantly different from those of the normal tendon. Moreover, the magnitude of local shear strain in the healing tissue under 4% tissue strain was significantly smaller than that in the normal tendon. Differences in the local strain field may be reflected in the cell nuclear shape and possibly the amount of mechanical stimuli applied to the cells during tendon deformation. Accordingly, restoration of a normal local mechanical environment in the healing tissue may be key to a better healing outcome of tendon injury.
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8
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Johnstone M, Xin C, Tan J, Martin E, Wen J, Wang RK. Aqueous outflow regulation - 21st century concepts. Prog Retin Eye Res 2021; 83:100917. [PMID: 33217556 PMCID: PMC8126645 DOI: 10.1016/j.preteyeres.2020.100917] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 10/09/2020] [Accepted: 10/12/2020] [Indexed: 12/24/2022]
Abstract
We propose an integrated model of aqueous outflow control that employs a pump-conduit system in this article. Our model exploits accepted physiologic regulatory mechanisms such as those of the arterial, venous, and lymphatic systems. Here, we also provide a framework for developing novel diagnostic and therapeutic strategies to improve glaucoma patient care. In the model, the trabecular meshwork distends and recoils in response to continuous physiologic IOP transients like the ocular pulse, blinking, and eye movement. The elasticity of the trabecular meshwork determines cyclic volume changes in Schlemm's canal (SC). Tube-like SC inlet valves provide aqueous entry into the canal, and outlet valve leaflets at collector channels control aqueous exit from SC. Connections between the pressure-sensing trabecular meshwork and the outlet valve leaflets dynamically control flow from SC. Normal function requires regulation of the trabecular meshwork properties that determine distention and recoil. The aqueous pump-conduit provides short-term pressure control by varying stroke volume in response to pressure changes. Modulating TM constituents that regulate stroke volume provides long-term control. The aqueous outflow pump fails in glaucoma due to the loss of trabecular tissue elastance, as well as alterations in ciliary body tension. These processes lead to SC wall apposition and loss of motion. Visible evidence of pump failure includes a lack of pulsatile aqueous discharge into aqueous veins and reduced ability to reflux blood into SC. These alterations in the functional properties are challenging to monitor clinically. Phase-sensitive OCT now permits noninvasive, quantitative measurement of pulse-dependent TM motion in humans. This proposed conceptual model and related techniques offer a novel framework for understanding mechanisms, improving management, and development of therapeutic options for glaucoma.
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Affiliation(s)
| | - Chen Xin
- Department of Ophthalmology, Beijing Anzhen Hospital, Capital Medical University, China.
| | - James Tan
- Doheny Eye Institute and UCLA Department of Ophthalmology, USA.
| | | | | | - Ruikang K Wang
- Department of Ophthalmology, University of Washington, USA; Department of Bioengineering, University of Washington, USA.
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9
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Gögele C, Hoffmann C, Konrad J, Merkel R, Schwarz S, Tohidnezhad M, Hoffmann B, Schulze-Tanzil GG. Cyclically stretched ACL fibroblasts emigrating from spheroids adapt their cytoskeleton and ligament-related expression profile. Cell Tissue Res 2021; 384:675-690. [PMID: 33835257 PMCID: PMC8211585 DOI: 10.1007/s00441-021-03416-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 01/13/2021] [Indexed: 01/09/2023]
Abstract
Mechanical stress of ligaments varies; hence, ligament fibroblasts must adapt their expression profile to novel mechanomilieus to ensure tissue resilience. Activation of the mechanoreceptors leads to a specific signal transduction, the so-called mechanotransduction. However, with regard to their natural three-dimensional (3D) microenvironment cell reaction to mechanical stimuli during emigrating from a 3D spheroid culture is still unclear. This study aims to provide a deeper understanding of the reaction profile of anterior cruciate ligament (ACL)-derived fibroblasts exposed to cyclic uniaxial strain in two-dimensional (2D) monolayer culture and during emigration from 3D spheroids with respect to cell survival, cell and cytoskeletal orientation, distribution, and expression profile. Monolayers and spheroids were cultured in crosslinked polydimethyl siloxane (PDMS) elastomeric chambers and uniaxially stretched (14% at 0.3 Hz) for 48 h. Cell vitality, their distribution, nuclear shape, stress fiber orientation, focal adhesions, proliferation, expression of ECM components such as sulfated glycosaminoglycans, collagen type I, decorin, tenascin C and cell-cell communication-related gap junctional connexin (CXN) 43, tendon-related markers Mohawk and tenomodulin (myodulin) were analyzed. In contrast to unstretched cells, stretched fibroblasts showed elongation of stress fibers, cell and cytoskeletal alignment perpendicular to strain direction, less rounded cell nuclei, increased numbers of focal adhesions, proliferation, amplified CXN43, and main ECM component expression in both cultures. The applied cyclic stretch protocol evoked an anabolic response and enhanced tendon-related marker expression in ACL-derived fibroblasts emigrating from 3D spheroids and seems also promising to support in future tissue formation in ACL scaffolds seeded in vitro with spheroids.
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Affiliation(s)
- Clemens Gögele
- Institute of Anatomy and Cell Biology, Paracelsus Medical University, Prof.-Ernst-Nathan Str. 1, 90419 Nuremberg and Salzburg, Nuremberg, Germany
- Department of Biosciences, Paris Lodron University Salzburg, Hellbrunnerstr. 34, 5020 Salzburg, Austria
| | - Christina Hoffmann
- Institute of Biological Information Processing: IBI-2, Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Jens Konrad
- Institute of Biological Information Processing: IBI-2, Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Rudolf Merkel
- Institute of Biological Information Processing: IBI-2, Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Silke Schwarz
- Institute of Anatomy and Cell Biology, Paracelsus Medical University, Prof.-Ernst-Nathan Str. 1, 90419 Nuremberg and Salzburg, Nuremberg, Germany
| | - Mersedeh Tohidnezhad
- Department of Anatomy and Cell Biology, RWTH Aachen University, Wendlingweg 2, 52074 Aachen, Germany
| | - Bernd Hoffmann
- Institute of Biological Information Processing: IBI-2, Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Gundula Gesine Schulze-Tanzil
- Institute of Anatomy and Cell Biology, Paracelsus Medical University, Prof.-Ernst-Nathan Str. 1, 90419 Nuremberg and Salzburg, Nuremberg, Germany
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10
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Blache U, Wunderli SL, Hussien AA, Stauber T, Flückiger G, Bollhalder M, Niederöst B, Fucentese SF, Snedeker JG. Inhibition of ERK 1/2 kinases prevents tendon matrix breakdown. Sci Rep 2021; 11:6838. [PMID: 33767224 PMCID: PMC7994809 DOI: 10.1038/s41598-021-85331-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Accepted: 02/26/2021] [Indexed: 12/14/2022] Open
Abstract
Tendon extracellular matrix (ECM) mechanical unloading results in tissue degradation and breakdown, with niche-dependent cellular stress directing proteolytic degradation of tendon. Here, we show that the extracellular-signal regulated kinase (ERK) pathway is central in tendon degradation of load-deprived tissue explants. We show that ERK 1/2 are highly phosphorylated in mechanically unloaded tendon fascicles in a vascular niche-dependent manner. Pharmacological inhibition of ERK 1/2 abolishes the induction of ECM catabolic gene expression (MMPs) and fully prevents loss of mechanical properties. Moreover, ERK 1/2 inhibition in unloaded tendon fascicles suppresses features of pathological tissue remodeling such as collagen type 3 matrix switch and the induction of the pro-fibrotic cytokine interleukin 11. This work demonstrates ERK signaling as a central checkpoint to trigger tendon matrix degradation and remodeling using load-deprived tissue explants.
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Affiliation(s)
- Ulrich Blache
- Department of Orthopedics, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
- Institute for Biomechanics, ETH Zurich, Zurich, Switzerland
| | - Stefania L Wunderli
- Department of Orthopedics, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
- Institute for Biomechanics, ETH Zurich, Zurich, Switzerland
| | - Amro A Hussien
- Department of Orthopedics, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
- Institute for Biomechanics, ETH Zurich, Zurich, Switzerland
| | - Tino Stauber
- Department of Orthopedics, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
- Institute for Biomechanics, ETH Zurich, Zurich, Switzerland
| | - Gabriel Flückiger
- Department of Orthopedics, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
- Institute for Biomechanics, ETH Zurich, Zurich, Switzerland
| | - Maja Bollhalder
- Department of Orthopedics, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
- Institute for Biomechanics, ETH Zurich, Zurich, Switzerland
| | - Barbara Niederöst
- Department of Orthopedics, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
- Institute for Biomechanics, ETH Zurich, Zurich, Switzerland
| | - Sandro F Fucentese
- Department of Orthopedics, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Jess G Snedeker
- Department of Orthopedics, Balgrist University Hospital, University of Zurich, Zurich, Switzerland.
- Institute for Biomechanics, ETH Zurich, Zurich, Switzerland.
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11
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Cell morphology and mechanosensing can be decoupled in fibrous microenvironments and identified using artificial neural networks. Sci Rep 2021; 11:5950. [PMID: 33723274 PMCID: PMC7961147 DOI: 10.1038/s41598-021-85276-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Accepted: 02/15/2021] [Indexed: 12/16/2022] Open
Abstract
Cells interpret cues from and interact with fibrous microenvironments through the body based on the mechanics and organization of these environments and the phenotypic state of the cell. This in turn regulates mechanoactive pathways, such as the localization of mechanosensitive factors. Here, we leverage the microscale heterogeneity inherent to engineered fiber microenvironments to produce a large morphologic data set, across multiple cells types, while simultaneously measuring mechanobiological response (YAP/TAZ nuclear localization) at the single cell level. This dataset describing a large dynamic range of cell morphologies and responses was coupled with a machine learning approach to predict the mechanobiological state of individual cells from multiple lineages. We also noted that certain cells (e.g., invasive cancer cells) or biochemical perturbations (e.g., modulating contractility) can limit the predictability of cells in a universal context. Leveraging this finding, we developed further models that incorporate biochemical cues for single cell prediction or identify individual cells that do not follow the established rules. The models developed here provide a tool for connecting cell morphology and signaling, incorporating biochemical cues in predictive models, and identifying aberrant cell behavior at the single cell level.
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12
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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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13
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Maeda E, Kuroyanagi K, Ando Y, Matsumoto T. Effects of Substrate Stiffness on Morphology and MMP-1 Gene Expression in Tenocytes Stimulated With Interleukin-1β. J Orthop Res 2020; 38:150-159. [PMID: 31254408 DOI: 10.1002/jor.24403] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Accepted: 06/18/2019] [Indexed: 02/04/2023]
Abstract
Tendon cells, tenocytes, are constantly subjected to mechanical stress in vivo, which maintains a level of cellular tension. When a tendon is subjected to overloading, local rupture of collagen fibers are induced, which deprives tenocytes of mechanical stress, lowers their cellular tension level and upregulates their catabolism. In addition, leukocytes are attracted to the rupture sites and produce interleukin-1β (IL-1β), and this exogenous IL-1β also stimulates tenocyte catabolism. We tested a hypothesis that catabolic tenocytes with low cellular tension at the rupture sites excessively respond to the exogenous IL-1β and further upregulate matrix metalloproteinase 1 (MMP-1) gene expression. Tenocytes from rabbit Achilles tendon were cultured on the following substrates: glass or polydimethylsiloxane micropillar substrates with a height of 2, 4, or 8 µm. Following a 3-day IL-1β stimulation at a concentration of 0, 1, 10, or 100 pM, the effects of IL-1β stimulation on cell morphology and MMP-1 gene expression was analysed with fluorescent microscopy and fluorescence in situ hybridization, respectively. In addition, the effects of IL-1β stimulation on cell membrane fluidity were examined. It was demonstrated that the cells on 8-µm-height micropillars exhibited a greater response than those on rigid substrates with flat (glass) and topologically the same surface (2-µm-height micropillars) to IL-1β when supplied at the same concentration. Besides this, membrane fluidity was lower in the cells on micropillars. Therefore, it appears that cellular attachment to softer substrates lowers the cellular actin cortex tension, reducing the membrane fluidity and possibly elevating the sensitivity of IL-1 receptors to ligand binding. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:150-159, 2020.
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Affiliation(s)
- Eijiro Maeda
- Biomechanics Laboratory, Department of Mechanical Systems Engineering, Graduate School of Engineering, Nagoya University, Nagoya, Japan
| | - Kaname Kuroyanagi
- Biomechanics Laboratory, Department of Mechanical Systems Engineering, Graduate School of Engineering, Nagoya University, Nagoya, Japan
| | - Yoriko Ando
- Biomechanics Laboratory, Department of Mechanical Systems Engineering, Graduate School of Engineering, Nagoya University, Nagoya, Japan
| | - Takeo Matsumoto
- Biomechanics Laboratory, Department of Mechanical Systems Engineering, Graduate School of Engineering, Nagoya University, Nagoya, Japan
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14
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Connizzo BK, Piet JM, Shefelbine SJ, Grodzinsky AJ. Age-associated changes in the response of tendon explants to stress deprivation is sex-dependent. Connect Tissue Res 2020; 61:48-62. [PMID: 31411079 PMCID: PMC6884684 DOI: 10.1080/03008207.2019.1648444] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Purpose of the Study: The incidence of tendon injuries increases dramatically with age, which presents a major clinical burden. While previous studies have sought to identify age-related changes in extracellular matrix structure and function, few have been able to explain fully why aged tissues are more prone to degeneration and injury. In addition, recent studies have also demonstrated that age-related processes in humans may be sex-dependent, which could be responsible for muddled conclusions in changes with age. In this study, we investigate short-term responses through an ex vivo explant culture model of stress deprivation that specifically questions how age and sex differentially affect the ability of tendons to respond to altered mechanical stimulus.Materials and Methods: We subjected murine flexor explants from young (4 months of age) and aged (22-24 months of age) male and female mice to stress-deprived culture conditions for up to 1 week and investigated changes in viability, cell metabolism and proliferation, matrix biosynthesis and composition, gene expression, and inflammatory responses throughout the culture period.Results and Conclusions: We found that aging did have a significant influence on the response to stress deprivation, demonstrating that aged explants have a less robust response overall with reduced metabolic activity, viability, proliferation, and biosynthesis. However, age-related changes appeared to be sex-dependent. Together, this work demonstrates that the aging process and the subsequent effect of age on the ability of tendons to respond to stress-deprivation are inherently different based on sex, where male explants favor increased activity, apoptosis, and matrix remodeling while female explants favor reduced activity and tissue preservation.
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Affiliation(s)
- Brianne K. Connizzo
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, United States,Correspondence: Brianne K. Connizzo, 70 Massachusetts Avenue, NE47-377, Cambridge, MA 02139, T: 617-253-2469,
| | - Judith M. Piet
- Department of Bioengineering, Northeastern University, Boston, MA 02115, United States
| | - Sandra J. Shefelbine
- Department of Bioengineering, Northeastern University, Boston, MA 02115, United States,Department of Mechanical and Industrial Engineering, Northeastern University, Boston, MA 02115, United States
| | - Alan J. Grodzinsky
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, United States,Center for Biomedical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, United States,Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA 02139, United States,Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, United States
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15
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Aberrant mechanosensing in injured intervertebral discs as a result of boundary-constraint disruption and residual-strain loss. Nat Biomed Eng 2019; 3:998-1008. [PMID: 31611678 PMCID: PMC6899202 DOI: 10.1038/s41551-019-0458-4] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Accepted: 08/28/2019] [Indexed: 12/21/2022]
Abstract
In fibrous tissues, pre-stressed boundary constraints at bone interfaces instil residual strain throughout the tissue, even when unloaded. For example, internal swelling pressures in the central nucleus pulposus of the intervertebral disc generate pre-strain in the outer annulus fibrosus. With injury and depressurization, these residual strains are lost. Here, we show that the loss of residual strains in the intervertebral disc alters the microenvironment and instigates aberrant tissue remodelling and the adoption of atypical cellular phenotypes. By using puncture surgery of the annulus fibrosus in rabbits, ex vivo puncture experiments, and electrospun nanofibrous scaffolds recapitulating evolving boundary constraints, we show that the loss of residual strain promotes short-term apoptosis and the emergence of a fibrotic phenotype, that local fibre organization and cellular contractility mediate this process, and that the aberrant cellular changes could be abrogated by targeting the cell-mechanosensing machinery with small molecules. Our findings indicate that injury to dense connective tissues under pre-strain alters boundary constraints and residual strain, leading to aberrant mechanosensing, which in turn promotes disease progression.
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16
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Jafari L, Hassanisaber H, Savard M, Gobeil F, Langelier E. Efficacy of Combining PRP and MMP Inhibitors in Treating Moderately Damaged Tendons Ex Vivo. J Orthop Res 2019; 37:1838-1847. [PMID: 31042324 DOI: 10.1002/jor.24319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Accepted: 03/25/2019] [Indexed: 02/04/2023]
Abstract
Platelet-rich plasma (PRP) and broad-spectrum matrix metalloproteinase inhibitors (MMPIs) have been used as therapeutic options for tendinopathy. However, mixed results have been reported regarding their efficacy. We posited that the combination of these two treatment strategies would be more beneficial for healing tendons than each treatment alone. Rat tail tendons were harvested and cultured without mechanical stress for 0, 4, or 10 days. Single and combination treatment with PRP and MMPIs with either broad- or narrow-spectrum (MMP-13 selective), was administered to 4-day stress-deprived (SD) tendons, an ex vivo model for moderate tendinopathy. This treatment was applied to the damaged tendons over 6 days. At the end of their culture time, the tendons were subjected to traction testing and pathohistology, immunohistochemistry, and viability assays. The results showed better histological features for the PRP + narrow-spectrum MMPI group compared with all individual treatment modalities. Moreover, higher fiber density, more elongated nucleus shape, smaller space between fibers, and a trend toward higher mechanical strength were noted for PRP + narrow-spectrum MMPI group compared with 10-day SD tendons. This study shows that the combination of PRP + narrow-spectrum MMPI is a potentially effective treatment approach for tendinopathy. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:1838-1847, 2019.
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Affiliation(s)
- Leila Jafari
- Department of Mechanical Engineering, Université de Sherbrooke, Sherbrooke, Québec J1K 2R1, Canada
| | - Hamid Hassanisaber
- Department of Chemical and Biotechnological Engineering, Université de Sherbrooke, Sherbrooke, Québec J1K 2R1, Canada
| | - Martin Savard
- Department of Pharmacology-Physiology, Université de Sherbrooke, Sherbrooke, Québec J1H 5N4, Canada
| | - Fernand Gobeil
- Department of Pharmacology-Physiology, Université de Sherbrooke, Sherbrooke, Québec J1H 5N4, Canada
| | - Eve Langelier
- Department of Mechanical Engineering, Université de Sherbrooke, Sherbrooke, Québec J1K 2R1, Canada
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17
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Tendon tissue microdamage and the limits of intrinsic repair. Matrix Biol 2019; 85-86:68-79. [PMID: 31325483 DOI: 10.1016/j.matbio.2019.07.008] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Revised: 06/19/2019] [Accepted: 07/17/2019] [Indexed: 02/08/2023]
Abstract
The transmission of mechanical muscle force to bone for musculoskeletal stability and movement is one of the most important functions of tendon. The load-bearing tendon core is composed of highly aligned collagen-rich fascicles interspersed with stromal cells (tenocytes). Despite being built to bear very high mechanical stresses, supra-physiological/repetitive mechanical overloading leads to tendon microdamage in fascicles, and potentially to tendon disease and rupture. To date, it is unclear to what extent intrinsic healing mechanisms of the tendon core compartment can repair microdamage. In the present study, we investigated the healing capacity of the tendon core compartment in an ex vivo tissue explant model. To do so, we isolated rat tail tendon fascicles, damaged them by applying a single stretch to various degrees of sub-rupture damage and longitudinally assessed downstream functional and structural changes over a period of several days. Functional damage was assessed by changes in the elastic modulus of the material stress-strain curves, and biological viability of the resident tenocytes. Structural damage was quantified using a fluorescent collagen hybridizing peptide (CHP) to label mechanically disrupted collagen structures. While we observed functional mechanical damage for strains above 2% of the initial fascicle length, structural collagen damage was only detectable for 6% strain and beyond. Minimally loaded/damaged fascicles (2-4% strain) progressively lost elastic modulus over the course of tissue culture, despite their collagen structures remaining intact with high degree of maintained cell viability. In contrast, more severely overloaded fascicles (6-8% strain) with damage at the molecular/collagen level showed no further loss of the elastic modulus but markedly decreased cell viability. Surprisingly, in these heavily damaged fascicles the elastic modulus partially recovered, an effect also seen in further experiments on devitalized fascicles, implying the possibility of a non-cellular but matrix-driven mechanism of molecular repair. Overall, our findings indicate that the tendon core has very little capacity for self-repair of microdamage. We conclude that stromal tenocytes likely do not play a major role in anabolic repair of tendon matrix microdamage, but rather mediate catabolic matrix breakdown and communication with extrinsic cells that are able to effect tissue repair.
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18
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Jafari L, Savard M, Gobeil F, Langelier E. Characterization of moderate tendinopathy in ex vivo stress-deprived rat tail tendons. Biomed Eng Online 2019; 18:54. [PMID: 31068196 PMCID: PMC6507059 DOI: 10.1186/s12938-019-0673-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Accepted: 04/20/2019] [Indexed: 12/02/2022] Open
Abstract
Background Stress deprivation (SD) has frequently been used as a model to study tendinopathy. Most of these studies have investigated either short-term (early tendinopathy) or long-term SD (advanced tendinopathy), while the transient mid-term SD has been given less attention. Therefore, the main objective of this study was to characterize mid-term SD. Methods To this end, live, healthy rat tail tendons (RTTs) were harvested and cultured without mechanical stress and then were divided into five groups based on their culture time (fresh, 2-day SD, 4-day SD, 6-day SD, and 10-day SD). For each group, the tendons were subjected to traction testing and pathohistology, immunohistochemistry, and viability assays. Results Our results showed that 4 days of SD resulted in moderate pathological changes in RTTs. These changes included increases in the space area between fibers, cell density, and fiber tortuosity as well as a decrease in collagen density and elongation of cell nuclei. No changes in the stress at failure of tendons were observed at this time point. Conclusions This simple ex vivo model is expected to be useful for studying the progression of tendinopathy as well as for testing potential mechanobiological or pharmacological therapy strategies to stop or reverse the progression of the pathology.
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Affiliation(s)
- Leila Jafari
- Department of Mechanical Engineering, Université de Sherbrooke, Sherbrooke, QC, J1K 2R1, Canada
| | - Martin Savard
- Department of Pharmacology-Physiology, Université de Sherbrooke - Campus de la santé, Sherbrooke, QC, J1H 5N4, Canada
| | - Fernand Gobeil
- Department of Pharmacology-Physiology, Université de Sherbrooke - Campus de la santé, Sherbrooke, QC, J1H 5N4, Canada
| | - Eve Langelier
- Department of Mechanical Engineering, Université de Sherbrooke, Sherbrooke, QC, J1K 2R1, Canada.
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19
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Chang JK, Emon MAB, Li CS, Yang Q, Chang HP, Yang Z, Wu CI, Saif MT, Rogers JA. Cytotoxicity and in Vitro Degradation Kinetics of Foundry-Compatible Semiconductor Nanomembranes and Electronic Microcomponents. ACS NANO 2018; 12:9721-9732. [PMID: 30160102 DOI: 10.1021/acsnano.8b04513] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Foundry-compatible materials and processing approaches serve as the foundations for advanced, active implantable microsystems that can dissolve in biofluids into biocompatible reaction products, with broad potential applications in biomedicine. The results reported here include in vitro studies of the dissolution kinetics and nanoscale bioresorption behaviors of device-grade thin films of Si, SiN x, SiO2, and W in the presence of dynamic cell cultures via atomic force microscopy and X-ray photoemission spectroscopy. In situ investigations of cell-extracellular mechanotransduction induced by cellular traction provide insights into the cytotoxicity of these same materials and of microcomponents formed with them using foundry-compatible processes, indicating potential cytotoxicity elicited by W at concentrations greater than 6 mM. The findings are of central relevance to the biocompatibility of modern Si-based electronics technologies as active, bioresorbable microsystems that interface with living tissues.
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Affiliation(s)
- Jan-Kai Chang
- Center for Bio-Integrated Electronics , Northwestern University , Evanston , Illinois 60208 , United States
| | - M A Bashar Emon
- Department of Mechanical Science and Engineering , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
| | - Chia-Shuo Li
- Graduate Institute of Photonics and Optoelectronics , National Taiwan University , Taipei 10617 , Taiwan
| | - Quansan Yang
- Center for Bio-Integrated Electronics , Northwestern University , Evanston , Illinois 60208 , United States
- Department of Mechanical Engineering , Northwestern University , Evanston , Illinois 60208 , United States
| | - Hui-Ping Chang
- Graduate Institute of Photonics and Optoelectronics , National Taiwan University , Taipei 10617 , Taiwan
- Frederick Seitz Materials Research Laboratory , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
| | - Zijian Yang
- Frederick Seitz Materials Research Laboratory , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
| | - Chih-I Wu
- Graduate Institute of Photonics and Optoelectronics , National Taiwan University , Taipei 10617 , Taiwan
| | - M Taher Saif
- Department of Mechanical Science and Engineering , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
| | - John A Rogers
- Center for Bio-Integrated Electronics , Northwestern University , Evanston , Illinois 60208 , United States
- Frederick Seitz Materials Research Laboratory , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
- Departments of Materials Science and Engineering, Biomedical Engineering, Neurological Surgery, Chemistry, Mechanical Engineering, Electrical Engineering and Computer Science, Simpson Querrey Institute for BioNanotechnology, McCormick School of Engineering, and Feinberg School of Medicine , Northwestern University , Evanston , Illinois 60208 , United States
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20
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Connizzo BK, Grodzinsky AJ. Release of pro-inflammatory cytokines from muscle and bone causes tenocyte death in a novel rotator cuff in vitro explant culture model. Connect Tissue Res 2018; 59:423-436. [PMID: 29447021 PMCID: PMC6240787 DOI: 10.1080/03008207.2018.1439486] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
PURPOSE Tendinopathy is a significant clinical problem thought to be associated with altered mechanical loading. Explant culture models allow researchers to alter mechanical loading in a controlled in vitro environment while maintaining tenocytes in their native matrix. However, current models do not accurately represent commonly injured tendons, ignoring contributions of associated musculature and bone, as well as regional collagen structure. This study details the characterization of amouse rotator cuff explant culture model, including bone, tendon, and muscle (BTM). MATERIALS AND METHODS Following harvest, BTM explants were maintained in stress-deprived culture for one week and tendon was then assessed for changes in cell viability, metabolism, matrix structure and content. RESULTS Matrix turnover occurred throughout culture as manifested in both gene expression and biosynthesis, but this did not translate to net changes in total collagen or sulfated glycosaminoglycan content. Furthermore, tendon structure was not significantly altered throughout culture. However, we found significant cell death in BTM tendons after 3 days in culture, which we hypothesize is cytokine-induced. Using a targeted multiplex assay, we found high levels of pro-inflammatory cytokines released to the culture medium from muscle and bone, levels that did cause cell deathin tendon-alone controls. CONCLUSIONS Overall, this model presents an innovative approach to understandingrotator cuff injury and tenocyte mechanobiology in a clinically-relevant tendon structure. Our model can be a powerful tool to investigate how mechanical and biological stimuli can alter normal tendon health and lead to tendon degeneration, and may provide a testbed for therapeutics for tendon repair.
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Affiliation(s)
- Brianne K. Connizzo
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, United States
| | - Alan J. Grodzinsky
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, United States,Center for Biomedical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, United States,Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA 02139, United States,Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, United States
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21
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Nichols AEC, Settlage RE, Werre SR, Dahlgren LA. Novel roles for scleraxis in regulating adult tenocyte function. BMC Cell Biol 2018; 19:14. [PMID: 30086712 PMCID: PMC6081934 DOI: 10.1186/s12860-018-0166-z] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Accepted: 07/30/2018] [Indexed: 12/15/2022] Open
Abstract
Background Tendinopathies are common and difficult to resolve due to the formation of scar tissue that reduces the mechanical integrity of the tissue, leading to frequent reinjury. Tenocytes respond to both excessive loading and unloading by producing pro-inflammatory mediators, suggesting that these cells are actively involved in the development of tendon degeneration. The transcription factor scleraxis (Scx) is required for the development of force-transmitting tendon during development and for mechanically stimulated tenogenesis of stem cells, but its function in adult tenocytes is less well-defined. The aim of this study was to further define the role of Scx in mediating the adult tenocyte mechanoresponse. Results Equine tenocytes exposed to siRNA targeting Scx or a control siRNA were maintained under cyclic mechanical strain before being submitted for RNA-seq analysis. Focal adhesions and extracellular matrix-receptor interaction were among the top gene networks downregulated in Scx knockdown tenocytes. Correspondingly, tenocytes exposed to Scx siRNA were significantly softer, with longer vinculin-containing focal adhesions, and an impaired ability to migrate on soft surfaces. Other pathways affected by Scx knockdown included increased oxidative phosphorylation and diseases caused by endoplasmic reticular stress, pointing to a larger role for Scx in maintaining tenocyte homeostasis. Conclusions Our study identifies several novel roles for Scx in adult tenocytes, which suggest that Scx facilitates mechanosensing by regulating the expression of several mechanosensitive focal adhesion proteins. Furthermore, we identified a number of other pathways and targets affected by Scx knockdown that have the potential to elucidate the role that tenocytes may play in the development of degenerative tendinopathy. Electronic supplementary material The online version of this article (10.1186/s12860-018-0166-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Anne E C Nichols
- Department of Large Animal Clinical Sciences, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, 205 Duck Pond Drive, Blacksburg, VA, 24061-0442, USA
| | - Robert E Settlage
- Advanced Research Computing, Virginia Biocomplexity Institute, Virginia Tech, Blacksburg, VA, 24061, USA
| | - Stephen R Werre
- Laboratory for Study Design and Statistical Analysis, Virginia-Maryland College of Veterinary Medicine, Blacksburg, VA, 24061, USA
| | - Linda A Dahlgren
- Department of Large Animal Clinical Sciences, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, 205 Duck Pond Drive, Blacksburg, VA, 24061-0442, USA.
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22
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Wunderli SL, Widmer J, Amrein N, Foolen J, Silvan U, Leupin O, Snedeker JG. Minimal mechanical load and tissue culture conditions preserve native cell phenotype and morphology in tendon-a novel ex vivo mouse explant model. J Orthop Res 2018; 36:1383-1390. [PMID: 28980724 DOI: 10.1002/jor.23769] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Accepted: 09/27/2017] [Indexed: 02/04/2023]
Abstract
Appropriate mechanical load is essential for tendon homeostasis and optimal tissue function. Due to technical challenges in achieving physiological mechanical loads in experimental tendon model systems, the research community still lacks well-characterized models of tissue homeostasis and physiological relevance. Toward this urgent goal, we present and characterize a novel ex vivo murine tail tendon explant model. Mouse tail tendon fascicles were extracted and cultured for 6 days in a load-deprived environment or in a custom-designed bioreactor applying low magnitude mechanical load (intermittent cycles to 1% strain, at 1 Hz) in serum-free tissue culture. Cells remained viable, as did collagen structure and mechanical properties in all tested conditions. Cell morphology in mechanically loaded tendon explants approximated native tendon, whereas load-deprived tendons lost their native cell morphology. These losses were reflected in altered gene expression, with mechanical loading tending to maintain tendon specific and matrix remodeling genes phenotypic of native tissue. We conclude from this study that ex vivo load deprivation of murine tendon in minimal culture medium results in a degenerative-like phenotype. We further conclude that onset of tissue degeneration can be suppressed by low-magnitude mechanical loading. Thus a minimal explant culture model featuring serum-free medium with low mechanical loads seems to provide a useful foundation for further investigations. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1383-1390, 2018.
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Affiliation(s)
- Stefania L Wunderli
- University Hospital Balgrist, University of Zurich, Balgrist Campus, Lengghalde 5, Zürich, CH-8008, Switzerland.,Institute for Biomechanics, ETH Zurich, Switzerland
| | - Jonas Widmer
- University Hospital Balgrist, University of Zurich, Balgrist Campus, Lengghalde 5, Zürich, CH-8008, Switzerland.,Institute for Biomechanics, ETH Zurich, Switzerland
| | - Niklaus Amrein
- University Hospital Balgrist, University of Zurich, Balgrist Campus, Lengghalde 5, Zürich, CH-8008, Switzerland.,Institute for Biomechanics, ETH Zurich, Switzerland
| | - Jasper Foolen
- University Hospital Balgrist, University of Zurich, Balgrist Campus, Lengghalde 5, Zürich, CH-8008, Switzerland.,Institute for Biomechanics, ETH Zurich, Switzerland
| | - Unai Silvan
- University Hospital Balgrist, University of Zurich, Balgrist Campus, Lengghalde 5, Zürich, CH-8008, Switzerland.,Institute for Biomechanics, ETH Zurich, Switzerland
| | - Olivier Leupin
- Novartis Institutes for BioMedical Research (NIBR), Basel, Switzerland
| | - Jess G Snedeker
- University Hospital Balgrist, University of Zurich, Balgrist Campus, Lengghalde 5, Zürich, CH-8008, Switzerland.,Institute for Biomechanics, ETH Zurich, Switzerland
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23
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Szczesny SE, Aeppli C, David A, Mauck RL. Fatigue loading of tendon results in collagen kinking and denaturation but does not change local tissue mechanics. J Biomech 2018. [PMID: 29519673 DOI: 10.1016/j.jbiomech.2018.02.014] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Fatigue loading is a primary cause of tendon degeneration, which is characterized by the disruption of collagen fibers and the appearance of abnormal (e.g., cartilaginous, fatty, calcified) tissue deposits. The formation of such abnormal deposits, which further weakens the tissue, suggests that resident tendon cells acquire an aberrant phenotype in response to fatigue damage and the resulting altered mechanical microenvironment. While fatigue loading produces clear changes in collagen organization and molecular denaturation, no data exist regarding the effect of fatigue on the local tissue mechanical properties. Therefore, the objective of this study was to identify changes in the local tissue stiffness of tendons after fatigue loading. We hypothesized that fatigue damage would reduce local tissue stiffness, particularly in areas with significant structural damage (e.g., collagen denaturation). We tested this hypothesis by identifying regions of local fatigue damage (i.e., collagen fiber kinking and molecular denaturation) via histologic imaging and by measuring the local tissue modulus within these regions via atomic force microscopy (AFM). Counter to our initial hypothesis, we found no change in the local tissue modulus as a consequence of fatigue loading, despite widespread fiber kinking and collagen denaturation. These data suggest that immediate changes in topography and tissue structure - but not local tissue mechanics - initiate the early changes in tendon cell phenotype as a consequence of fatigue loading that ultimately culminate in tendon degeneration.
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Affiliation(s)
- Spencer E Szczesny
- Department of Orthopaedic Surgery, University of Pennsylvania, 110 Stemmler Hall, 36th Street & Hamilton Walk, Philadelphia, PA 19104, United States; Department of Biomedical Engineering, Department of Orthopaedics and Rehabilitation, Pennsylvania State University, 205 Hallowell Building, University Park, PA 16802, United States.
| | - Céline Aeppli
- Eidgenössische Technische Hochschule, Rämistrasse 101, 8092 Zürich, Switzerland
| | - Alexander David
- Department of Bioengineering, 240 Skirkanich Hall, 210 South 33rd Street, University of Pennsylvania, Philadelphia, PA 19104, United States
| | - Robert L Mauck
- Department of Orthopaedic Surgery, University of Pennsylvania, 110 Stemmler Hall, 36th Street & Hamilton Walk, Philadelphia, PA 19104, United States; Department of Bioengineering, 240 Skirkanich Hall, 210 South 33rd Street, University of Pennsylvania, Philadelphia, PA 19104, United States; Translational Musculoskeletal Research Center, Corporal Michael J. Crescenz Veterans Affairs Medical Center, 3900 Woodland Avenue, Philadelphia, PA 19104, United States
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Snedeker JG, Foolen J. Tendon injury and repair - A perspective on the basic mechanisms of tendon disease and future clinical therapy. Acta Biomater 2017; 63:18-36. [PMID: 28867648 DOI: 10.1016/j.actbio.2017.08.032] [Citation(s) in RCA: 199] [Impact Index Per Article: 28.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Revised: 08/16/2017] [Accepted: 08/25/2017] [Indexed: 12/16/2022]
Abstract
Tendon is an intricately organized connective tissue that efficiently transfers muscle force to the bony skeleton. Its structure, function, and physiology reflect the extreme, repetitive mechanical stresses that tendon tissues bear. These mechanical demands also lie beneath high clinical rates of tendon disorders, and present daunting challenges for clinical treatment of these ailments. This article aims to provide perspective on the most urgent frontiers of tendon research and therapeutic development. We start by broadly introducing essential elements of current understanding about tendon structure, function, physiology, damage, and repair. We then introduce and describe a novel paradigm explaining tendon disease progression from initial accumulation of damage in the tendon core to eventual vascular recruitment from the surrounding synovial tissues. We conclude with a perspective on the important role that biomaterials will play in translating research discoveries to the patient. STATEMENT OF SIGNIFICANCE Tendon and ligament problems represent the most frequent musculoskeletal complaints for which patients seek medical attention. Current therapeutic options for addressing tendon disorders are often ineffective, and the need for improved understanding of tendon physiology is urgent. This perspective article summarizes essential elements of our current knowledge on tendon structure, function, physiology, damage, and repair. It also describes a novel framework to understand tendon physiology and pathophysiology that may be useful in pushing the field forward.
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Mehdizadeh A, Gardiner BS, Lavagnino M, Smith DW. Predicting tenocyte expression profiles and average molecular concentrations in Achilles tendon ECM from tissue strain and fiber damage. Biomech Model Mechanobiol 2017; 16:1329-1348. [DOI: 10.1007/s10237-017-0890-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Accepted: 02/18/2017] [Indexed: 11/28/2022]
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Lavagnino M, Brooks AE, Oslapas AN, Gardner KL, Arnoczky SP. Crimp length decreases in lax tendons due to cytoskeletal tension, but is restored with tensional homeostasis. J Orthop Res 2017; 35:573-579. [PMID: 27878991 DOI: 10.1002/jor.23489] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Accepted: 11/10/2016] [Indexed: 02/04/2023]
Abstract
Collagen crimp morphology is thought to contribute to the material behavior of tendons and may reflect the local mechanobiological environment of tendon cells. Following loss of collagen tension in tendons, tenocytes initiate a contraction response that shortens tendon length which, in turn, may alter crimp patterns. We hypothesized that changes in the crimp pattern of tendons are the result of cell-based contractions which are governed by relative tautness/laxity of the collagen matrix. To determine the relationship between crimp pattern and tensional homeostasis, rat tail tendon fascicles (RTTfs) were either allowed to freely contract or placed in clamps with 10% laxity for 7 days. The freely contracting RTTfs showed a significant decrease in percent crimp length on both day 5 (3.66%) and day 7 (7.70%). This decrease in crimp length significantly correlated with the decrease in freely contracting RTTf length. Clamped RTTfs demonstrated a significant decrease in percent crimp length on day 5 (1.7%), but no significant difference in percent crimp length on day 7 (0.57%). The results demonstrate that the tendon crimp pattern appears to be under cellular control and is a reflection of the local mechanobiological environment of the extracellular matrix. The ability of tenocytes to actively alter the crimp pattern of collagen fibers also suggests that tenocytes can influence the viscoelastic properties of tendon. Understanding the interactions between tenocytes and their extracellular matrix may lead to further insight into the role tendon cells play in maintaining tendon heath and homeostasis. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:573-579, 2017.
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Affiliation(s)
- Michael Lavagnino
- Laboratory for Comparative Orthopaedic Research, College of Veterinary Medicine, Michigan State University, 784 Wilson Road, East Lansing, Michigan, 48824
| | - Andrew E Brooks
- Laboratory for Comparative Orthopaedic Research, College of Veterinary Medicine, Michigan State University, 784 Wilson Road, East Lansing, Michigan, 48824
| | - Anna N Oslapas
- Laboratory for Comparative Orthopaedic Research, College of Veterinary Medicine, Michigan State University, 784 Wilson Road, East Lansing, Michigan, 48824
| | - Keri L Gardner
- Laboratory for Comparative Orthopaedic Research, College of Veterinary Medicine, Michigan State University, 784 Wilson Road, East Lansing, Michigan, 48824
| | - Steven P Arnoczky
- Laboratory for Comparative Orthopaedic Research, College of Veterinary Medicine, Michigan State University, 784 Wilson Road, East Lansing, Michigan, 48824
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Kokubun T, Kanemura N, Murata K, Moriyama H, Morita S, Jinno T, Ihara H, Takayanagi K. Effect of Changing the Joint Kinematics of Knees With a Ruptured Anterior Cruciate Ligament on the Molecular Biological Responses and Spontaneous Healing in a Rat Model. Am J Sports Med 2016; 44:2900-2910. [PMID: 27507845 DOI: 10.1177/0363546516654687] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BACKGROUND The poor healing capacity of a completely ruptured anterior cruciate ligament (ACL) has been attributed to an insufficient vascular supply, cellular metabolism, and deficient premature scaffold formation because of the unique intra-articular environment. However, previous studies have focused on intra-articular factors without considering extra-articular factors, including the biomechanical aspects of ACL-deficient knees. HYPOTHESIS Changing the joint kinematics of an ACL-ruptured knee will improve cellular biological responses and lead to spontaneous healing through the mechanotransduction mechanism. STUDY DESIGN Controlled laboratory study. METHODS A total of 66 skeletally mature Wistar rats were randomly assigned to a sham-operated group (SO), ACL-transection group (ACL-T), controlled abnormal movement group (CAM), and an intact group (IN). The ACL was completely transected at the midportion in the ACL-T and CAM groups, and the CAM group underwent extra-articular braking to control for abnormal tibial translation. The SO group underwent skin and joint capsule incisions and tibial drilling, without ACL transection and extra-articular braking. The animals were allowed full cage activity until sacrifice at 1, 2, 4, 6, and 8 weeks postoperatively for histological, molecular biological, and biomechanical assessment. RESULTS All injured ACLs in the ACL-T group were not healed, but those in the CAM group healed spontaneously, showing a typical ligament healing response. Regarding the molecular biological response, there was an upregulation of anabolic factors (ie, transforming growth factor-β) and downregulation of catabolic factors (ie, matrix metalloproteinase). Examination of the mechanical properties at 8 weeks after injury showed that >50% of the strength of the intact ACL had returned. CONCLUSION Our results suggest that changing the joint kinematics of knees with a ruptured ACL alters the molecular biological responses and leads to spontaneous healing. These data support our hypothesis that the mechanotransduction mechanism mediates molecular responses and determines whether the ACL will heal. CLINICAL RELEVANCE Elucidating the relationship between the mechanotransduction mechanism and healing responses in knees with completely ruptured ACLs may result in the development of novel nonsurgical treatment that enables the ACL to spontaneously heal in patients who are not suitable for reconstruction.
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Affiliation(s)
- Takanori Kokubun
- Department of Physical Therapy, Faculty of Health and Social Services, Saitama Prefectural University, Saitama, Japan .,Division of Rehabilitation Medicine, Graduate School of Medical and Dental Science, Tokyo Medical and Dental University, Tokyo, Japan
| | - Naohiko Kanemura
- Department of Physical Therapy, Faculty of Health and Social Services, Saitama Prefectural University, Saitama, Japan
| | - Kenji Murata
- Department of Physical Therapy, Faculty of Health and Social Services, Saitama Prefectural University, Saitama, Japan
| | - Hideki Moriyama
- Department of Rehabilitation Science, Graduate School of Health Science, Kobe University, Hyogo, Japan
| | - Sadao Morita
- Division of Rehabilitation Medicine, Graduate School of Medical and Dental Science, Tokyo Medical and Dental University, Tokyo, Japan
| | - Tetsuya Jinno
- Division of Orthopaedics, Graduate School of Medical and Dental Science, Tokyo Medical and Dental University, Tokyo, Japan
| | - Hidetoshi Ihara
- Department of Orthopaedic Surgery, Kyushu Rosai Hospital, Fukuoka, Japan
| | - Kiyomi Takayanagi
- Department of Physical Therapy, Faculty of Health and Social Services, Saitama Prefectural University, Saitama, Japan
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Hsu JE, Horneff JG, Gee AO. Immobilization After Rotator Cuff Repair: What Evidence Do We Have Now? Orthop Clin North Am 2016; 47:169-77. [PMID: 26614931 DOI: 10.1016/j.ocl.2015.08.017] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Recurrent tears after rotator cuff repair are common. Postoperative rehabilitation after rotator cuff repair is a modifiable factor controlled by the surgeon that can affect re-tear rates. Some surgeons prefer early mobilization after rotator cuff repair, whereas others prefer a period of immobilization to protect the repair site. The tendon-healing process incorporates biochemical and biomechanical responses to mechanical loading. Healing can be optimized with controlled loading. Complete load removal and chronic overload can be deleterious to the process. Several randomized clinical studies have also characterized the role of postoperative mobilization after rotator cuff repair.
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Affiliation(s)
- Jason E Hsu
- Department of Orthopaedics and Sports Medicine, University of Washington, Seattle, WA 98195, USA
| | - John G Horneff
- Department of Orthopaedic Surgery, University of Pennsylvania, 2 Silverstein Pavilion, 3400 Spruce Street, Philadelphia, PA 19104, USA
| | - Albert O Gee
- Department of Orthopaedics and Sports Medicine, University of Washington, Seattle, WA 98195, USA.
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Cell Signaling in Tenocytes: Response to Load and Ligands in Health and Disease. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 920:79-95. [DOI: 10.1007/978-3-319-33943-6_7] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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Wang T, Lin Z, Ni M, Thien C, Day RE, Gardiner B, Rubenson J, Kirk TB, Smith DW, Wang A, Lloyd DG, Wang Y, Zheng Q, Zheng MH. Cyclic mechanical stimulation rescues achilles tendon from degeneration in a bioreactor system. J Orthop Res 2015; 33:1888-96. [PMID: 26123799 DOI: 10.1002/jor.22960] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/18/2015] [Accepted: 05/30/2015] [Indexed: 02/04/2023]
Abstract
Physiotherapy is one of the effective treatments for tendinopathy, whereby symptoms are relieved by changing the biomechanical environment of the pathological tendon. However, the underlying mechanism remains unclear. In this study, we first established a model of progressive tendinopathy-like degeneration in the rabbit Achilles. Following ex vivo loading deprivation culture in a bioreactor system for 6 and 12 days, tendons exhibited progressive degenerative changes, abnormal collagen type III production, increased cell apoptosis, and weakened mechanical properties. When intervention was applied at day 7 for another 6 days by using cyclic tensile mechanical stimulation (6% strain, 0.25 Hz, 8 h/day) in a bioreactor, the pathological changes and mechanical properties were almost restored to levels seen in healthy tendon. Our results indicated that a proper biomechanical environment was able to rescue early-stage pathological changes by increased collagen type I production, decreased collagen degradation and cell apoptosis. The ex vivo model developed in this study allows systematic study on the effect of mechanical stimulation on tendon biology.
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Affiliation(s)
- Tao Wang
- Division of Orthopaedic Surgery, Department of Surgery, Guangdong General Hospital, Guangdong Academy of Medicine Science, Guangzhou, Guangdong, China.,Centre for Orthopaedic Translational Research, School of Surgery, University of Western Australia, Nedlands, Australia
| | - Zhen Lin
- Centre for Orthopaedic Translational Research, School of Surgery, University of Western Australia, Nedlands, Australia
| | - Ming Ni
- Department of Orthopaedics, The General Hospital of Chinese People's Liberation Army, Beijing, China
| | - Christine Thien
- Centre for Orthopaedic Translational Research, School of Surgery, University of Western Australia, Nedlands, Australia
| | - Robert E Day
- Department of Medical Engineering and Physics, Royal Perth Hospital, Perth, Australia
| | - Bruce Gardiner
- School of Computer Science and Software Engineering, University of Western Australia, Crawley, Australia
| | - Jonas Rubenson
- School of Sport Science, Exercise and Health, University of Western Australia, Crawley, Australia
| | | | - David W Smith
- School of Computer Science and Software Engineering, University of Western Australia, Crawley, Australia
| | - Allan Wang
- Sir Charles Gairdner Hospital, Perth, Australia
| | - David G Lloyd
- Centre for Musculoskeletal Research, Griffith Health Institute, Griffith University, Gold Coast, Australia
| | - Yan Wang
- Department of Orthopaedics, The General Hospital of Chinese People's Liberation Army, Beijing, China
| | - Qiujian Zheng
- Division of Orthopaedic Surgery, Department of Surgery, Guangdong General Hospital, Guangdong Academy of Medicine Science, Guangzhou, Guangdong, China
| | - Ming H Zheng
- Centre for Orthopaedic Translational Research, School of Surgery, University of Western Australia, Nedlands, Australia
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31
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Andarawis-Puri N, Flatow EL, Soslowsky LJ. Tendon basic science: Development, repair, regeneration, and healing. J Orthop Res 2015; 33:780-4. [PMID: 25764524 PMCID: PMC4427041 DOI: 10.1002/jor.22869] [Citation(s) in RCA: 173] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Accepted: 02/16/2015] [Indexed: 02/04/2023]
Abstract
Tendinopathy and tendon rupture are common and disabling musculoskeletal conditions. Despite the prevalence of these injuries, a limited number of investigators are conducting fundamental, basic science studies focused on understanding processes governing tendinopathies and tendon healing. Development of effective therapeutics is hindered by the lack of fundamental guiding data on the biology of tendon development, signal transduction, mechanotransduction, and basic mechanisms underlying tendon pathogenesis and healing. To propel much needed progress, the New Frontiers in Tendon Research Conference, co-sponsored by NIAMS/NIH, the Orthopaedic Research Society, and the Icahn School of Medicine at Mount Sinai, was held to promote exchange of ideas between tendon researchers and basic science experts from outside the tendon field. Discussed research areas that are underdeveloped and represent major hurdles to the progress of the field will be presented in this review. To address some of these outstanding questions, conference discussions and breakout sessions focused on six topic areas (Cell Biology and Mechanics, Functional Extracellular Matrix, Development, Mechano-biology, Scarless Healing, and Mechanisms of Injury and Repair), which are reviewed in this special issue and briefly presented in this review. Review articles in this special issue summarize the progress in the field and identify essential new research directions.
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Affiliation(s)
- Nelly Andarawis-Puri
- Leni and Peter W. May Department of Orthopaedics, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1188, New York, New York 10029
| | - Evan L. Flatow
- Leni and Peter W. May Department of Orthopaedics, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1188, New York, New York 10029
| | - Louis J. Soslowsky
- McKay Orthopaedic Research Laboratory, University of Pennsylvania, Philadelphia, Pennsylvania
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Lavagnino M, Wall ME, Little D, Banes AJ, Guilak F, Arnoczky SP. Tendon mechanobiology: Current knowledge and future research opportunities. J Orthop Res 2015; 33:813-22. [PMID: 25763779 PMCID: PMC4524513 DOI: 10.1002/jor.22871] [Citation(s) in RCA: 90] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Accepted: 02/13/2015] [Indexed: 02/04/2023]
Abstract
Tendons mainly function as load-bearing tissues in the muscloskeletal system; transmitting loads from muscle to bone. Tendons are dynamic structures that respond to the magnitude, direction, frequency, and duration of physiologic as well as pathologic mechanical loads via complex interactions between cellular pathways and the highly specialized extracellular matrix. This paper reviews the evolution and current knowledge of mechanobiology in tendon development, homeostasis, disease, and repair. In addition, we review several novel mechanotransduction pathways that have been identified recently in other tissues and cell types, providing potential research opportunities in the field of tendon mechanobiology. We also highlight current methods, models, and technologies being used in a wide variety of mechanobiology research that could be investigated in the context of their potential applicability for answering some of the fundamental unanswered questions in this field. The article concludes with a review of the major questions and future goals discussed during the recent ORS/ISMMS New Frontiers in Tendon Research Conference held on September 10 and 11, 2014 in New York City.
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Affiliation(s)
- Michael Lavagnino
- Laboratory for Comparative Orthopaedic Research, College of Veterinary Medicine Michigan State University, East Lansing, Michigan
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Lavagnino M, Gardner KL, Arnoczky SP. High magnitude, in vitro, biaxial, cyclic tensile strain induces actin depolymerization in tendon cells. Muscles Ligaments Tendons J 2015; 5:124-128. [PMID: 26261792 PMCID: PMC4496012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
BACKGROUND the cytoskeleton is a dynamic arrangement of actin filaments that maintain cell shape and are vital in mediating the mechanobiological response of the cell. METHODS to determine the cytoskeletal response to varying in vitro, biaxial stretch amplitudes, rat-tail tendon cells were paired into control and cyclically strained groups of 4.75, 9.5, or 12% strain at 1 Hz for 2 hours and the actin cytoskeleton stained. The cells were analyzed for actin staining intensity as a measure of relative depolymerization and for cell shape. Collagenase gene expression was measured in cells undergoing 12% cyclic strain at 1 Hz for 24 hours. RESULTS there was no significant difference in the degree of actin staining intensity between the control group and cells strained at either 4.75 or 9.5%. However, cells strained at 12% demonstrated a significant decrease in actin staining intensity (depolymerization) compared to control cells, increased collagenase expression by 81%, and a clear shift towards a more rounded cell shape. CONCLUSION the results of this study demonstrate that the previously reported induction of collagenase activity associated with the application of high magnitude, in vitro, tensile strains may actually be a result of cytoskeletal depolymerization, which causes loss of tensional homeostasis and alteration of cell shape.
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Affiliation(s)
- Michael Lavagnino
- Corresponding author: Michael Lavagnino, Laboratory for Comparative Orthopaedic Research, Michigan State University, 784 Wilson Rd, 48824 East Lansing, Michigan, USA, E-mail:
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34
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Thorpe CT, Chaudhry S, Lei II, Varone A, Riley GP, Birch HL, Clegg PD, Screen HRC. Tendon overload results in alterations in cell shape and increased markers of inflammation and matrix degradation. Scand J Med Sci Sports 2014; 25:e381-91. [DOI: 10.1111/sms.12333] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/05/2014] [Indexed: 12/22/2022]
Affiliation(s)
- C. T. Thorpe
- Institute of Bioengineering; School of Engineering and Materials Science; Queen Mary University of London; London UK
| | - S. Chaudhry
- Institute of Bioengineering; School of Engineering and Materials Science; Queen Mary University of London; London UK
| | - I. I. Lei
- Institute of Bioengineering; School of Engineering and Materials Science; Queen Mary University of London; London UK
| | - A. Varone
- Institute of Bioengineering; School of Engineering and Materials Science; Queen Mary University of London; London UK
| | - G. P. Riley
- School of Biological Sciences; University of East Anglia; Norwich UK
| | - H. L. Birch
- Institute of Orthopaedics and Musculoskeletal Science; University College London; Stanmore UK
| | - P. D. Clegg
- Department of Musculoskeletal Biology; Institute of Ageing and Chronic Disease; University of Liverpool; Neston UK
| | - H. R. C. Screen
- Institute of Bioengineering; School of Engineering and Materials Science; Queen Mary University of London; London UK
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Rich T, Patterson-Kane JC. Science-in-brief: What is needed to prevent tendon injury in equine athletes? A conversation between researchers and industry stakeholders. Equine Vet J 2014; 46:393-8. [DOI: 10.1111/evj.12269] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Affiliation(s)
- T. Rich
- Institute of Infection, Immunity and Inflammation; University of Glasgow; Glasgow UK
| | - J. C. Patterson-Kane
- Institute of Infection, Immunity and Inflammation; University of Glasgow; Glasgow UK
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Ballard GA, Warnock JJ, Bobe G, Duesterdieck-Zellmer KF, Baker L, Baltzer WI, Ott J. Comparison of meniscal fibrochondrocyte and synoviocyte bioscaffolds toward meniscal tissue engineering in the dog. Res Vet Sci 2014; 97:400-8. [PMID: 24856453 DOI: 10.1016/j.rvsc.2014.05.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2013] [Revised: 02/03/2014] [Accepted: 05/04/2014] [Indexed: 02/06/2023]
Abstract
Tissue engineering is a promising field of study toward curing the meniscal deficient stifle; however the ideal cell type for this task is not known. We describe here the extraction of synoviocytes and meniscal fibrochondrocytes from arthroscopic debris from six dogs, which were cultured as tensioned bioscaffolds to synthesize meniscal-like fibrocartilage sheets. Despite the diseased status of the original tissues, synoviocytes and meniscal fibrochondrocytes had high viability at the time of removal from the joint. Glycosaminoglycan and collagen content of bioscaffolds did not differ. Meniscal fibrochondrocyte bioscaffolds contained more type II collagen, but collagen deposition was disorganized, with only 30-40% of cells viable. The collagen of synoviocyte bioscaffolds was organized into sheets and bands and 80-90% of cells were viable. Autologous, diseased meniscal fibrochondrocytes and synoviocytes are plausible cell sources for future meniscal tissue engineering research, however cell viability of meniscal fibrochondrocytes in the tensioned bioscaffolds was low.
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Affiliation(s)
- George A Ballard
- College of Veterinary Medicine, Oregon State University, 105 Magruder Hall, 700 SW 30th St., Corvallis, OR 97331, USA
| | - Jennifer J Warnock
- College of Veterinary Medicine, Oregon State University, 105 Magruder Hall, 700 SW 30th St., Corvallis, OR 97331, USA.
| | - Gerd Bobe
- Linus Pauling Institute, Oregon State University, 307 Linus Pauling Science Center, Corvallis, OR 97331, USA
| | - Katja F Duesterdieck-Zellmer
- College of Veterinary Medicine, Oregon State University, 105 Magruder Hall, 700 SW 30th St., Corvallis, OR 97331, USA
| | - Lindsay Baker
- College of Veterinary Medicine, Oregon State University, 105 Magruder Hall, 700 SW 30th St., Corvallis, OR 97331, USA
| | - Wendy I Baltzer
- College of Veterinary Medicine, Oregon State University, 105 Magruder Hall, 700 SW 30th St., Corvallis, OR 97331, USA
| | - Jesse Ott
- College of Veterinary Medicine, Oregon State University, 105 Magruder Hall, 700 SW 30th St., Corvallis, OR 97331, USA
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Hettrich CM, Gasinu S, Beamer BS, Stasiak M, Fox A, Birmingham P, Ying O, Deng XH, Rodeo SA. The effect of mechanical load on tendon-to-bone healing in a rat model. Am J Sports Med 2014; 42:1233-41. [PMID: 24692434 DOI: 10.1177/0363546514526138] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BACKGROUND Joint motion is commonly prescribed after tendon repair surgeries such as rotator cuff repairs; however, the ideal rehabilitation program to optimize tendon-to-bone healing is unknown. HYPOTHESES (1) Delayed loading would result in a mechanically stronger and better organized tendon-to-bone interface compared with prolonged immobilization or immediate loading. (2) Low-magnitude load would lead to superior healing compared with high-magnitude load. STUDY DESIGN Controlled laboratory study. METHODS A total of 192 rats underwent unilateral patellar tendon detachment and repair followed by placement of a custom external fixator. Rats were assigned to immobilization, immediate postoperative loading, or delayed-onset loading (4- or 10-day delay). Loading was controlled using a specially designed motorized device to apply constant strain until 3 N (low load) or 6 N (high load) of axial tensile force was reached through the healing bone-tendon complex for 50 cycles per day. Rats were sacrificed at 4, 10, 21, or 28 days postoperatively for histomorphometric, immunohistochemical, radiographic, molecular, and biomechanical analyses. RESULTS The load to failure was significantly higher in the immobilized group compared with the immediate and delayed loading groups (P < .05). Compared with loaded specimens, the immobilized specimens had significantly less fibrocartilage (at 4, 10, and 28 days), significantly better collagen fiber organization (at 4, 10, and 21 days), decreased expression of matrix metalloproteinase-13 (at 10, 21, and 28 days), and significantly fewer apoptotic cells (at 21 and 28 days). Micro-computed tomographic analyses showed that the 3-N immediate load group had significantly less total volume (P = .012), bone volume (P = .012), and bone mineral density (P = .023) for cortical bone, and the immobilized group had significantly more specimens with new bone formation at the enthesis (100%; P = .001). CONCLUSION Immobilization results in a stronger tendon-bone complex, with less scar tissue and a more organized tendon-bone interface compared with all loading regimens in this study. CLINICAL RELEVANCE Given the relatively high rate of failure after rotator cuff and other tendon-to-bone repairs, identification of optimal rehabilitation programs postoperatively is an important research goal.
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Affiliation(s)
- Carolyn M Hettrich
- Carolyn M. Hettrich, Department of Orthopaedics and Rehabilitation, University of Iowa Sports Medicine Center, 2701 Prairie Meadow Drive, Iowa City, IA 52242, USA.
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Bayer ML, Schjerling P, Herchenhan A, Zeltz C, Heinemeier KM, Christensen L, Krogsgaard M, Gullberg D, Kjaer M. Release of tensile strain on engineered human tendon tissue disturbs cell adhesions, changes matrix architecture, and induces an inflammatory phenotype. PLoS One 2014; 9:e86078. [PMID: 24465881 PMCID: PMC3897642 DOI: 10.1371/journal.pone.0086078] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Accepted: 12/11/2013] [Indexed: 11/18/2022] Open
Abstract
Mechanical loading of tendon cells results in an upregulation of mechanotransduction signaling pathways, cell-matrix adhesion and collagen synthesis, but whether unloading removes these responses is unclear. We investigated the response to tension release, with regard to matrix proteins, pro-inflammatory mediators and tendon phenotypic specific molecules, in an in vitro model where tendon-like tissue was engineered from human tendon cells. Tissue sampling was performed 1, 2, 4 and 6 days after surgical de-tensioning of the tendon construct. When tensile stimulus was removed, integrin type collagen receptors showed a contrasting response with a clear drop in integrin subunit α11 mRNA and protein expression, and an increase in α2 integrin mRNA and protein levels. Further, specific markers for tendon cell differentiation declined and normal tendon architecture was disturbed, whereas pro-inflammatory molecules were upregulated. Stimulation with the cytokine TGF-β1 had distinct effects on some tendon-related genes in both tensioned and de-tensioned tissue. These findings indicate an important role of mechanical loading for cellular and matrix responses in tendon, including that loss of tension leads to a decrease in phenotypical markers for tendon, while expression of pro-inflammatory mediators is induced.
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Affiliation(s)
- Monika L Bayer
- Institute of Sports Medicine, Department of Orthopedic Surgery M, Bispebjerg Hospital and Center for Healthy Aging, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Peter Schjerling
- Institute of Sports Medicine, Department of Orthopedic Surgery M, Bispebjerg Hospital and Center for Healthy Aging, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Andreas Herchenhan
- Institute of Sports Medicine, Department of Orthopedic Surgery M, Bispebjerg Hospital and Center for Healthy Aging, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Cedric Zeltz
- Department of Biomedicine, University of Bergen, Bergen, Norway
| | - Katja M Heinemeier
- Institute of Sports Medicine, Department of Orthopedic Surgery M, Bispebjerg Hospital and Center for Healthy Aging, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Lise Christensen
- Department of Pathology, Bispebjerg Hospital, University of Copenhagen, Copenhagen, Denmark
| | - Michael Krogsgaard
- Section for Sports Traumatology, Department of Orthopedic Surgery M, Bispebjerg Hospital, University of Copenhagen, Copenhagen, Denmark
| | - Donald Gullberg
- Department of Biomedicine, University of Bergen, Bergen, Norway
| | - Michael Kjaer
- Institute of Sports Medicine, Department of Orthopedic Surgery M, Bispebjerg Hospital and Center for Healthy Aging, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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39
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Grigg NL, Wearing SC, O’Toole JM, Smeathers JE. The effect of exercise repetition on the frequency characteristics of motor output force: Implications for Achilles tendinopathy rehabilitation. J Sci Med Sport 2014; 17:13-7. [DOI: 10.1016/j.jsams.2013.03.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Revised: 03/18/2013] [Accepted: 03/28/2013] [Indexed: 11/30/2022]
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40
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Synoviocyte neotissues towards in vitro meniscal tissue engineering. Res Vet Sci 2013; 95:1201-9. [DOI: 10.1016/j.rvsc.2013.07.026] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2013] [Revised: 07/25/2013] [Accepted: 07/27/2013] [Indexed: 01/24/2023]
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41
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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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42
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Jones ER, Jones GC, Legerlotz K, Riley GP. Cyclical strain modulates metalloprotease and matrix gene expression in human tenocytes via activation of TGFβ. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1833:2596-2607. [PMID: 23830915 PMCID: PMC3898605 DOI: 10.1016/j.bbamcr.2013.06.019] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/27/2013] [Revised: 06/17/2013] [Accepted: 06/20/2013] [Indexed: 12/11/2022]
Abstract
Tendinopathies are a range of diseases characterised by degeneration and chronic tendon pain and represent a significant cause of morbidity. Relatively little is known about the underlying mechanisms; however onset is often associated with physical activity. A number of molecular changes have been documented in tendinopathy such as a decrease in overall collagen content, increased extracellular matrix turnover and protease activity. Metalloproteinases are involved in the homeostasis of the extracellular matrix and expression is regulated by mechanical strain. The aims of this study were to determine the effects of strain upon matrix turnover by measuring metalloproteinase and matrix gene expression and to elucidate the mechanism of action. Primary Human Achilles tenocytes were seeded in type I rat tail collagen gels in a Flexcell™ tissue train system and subjected to 5% cyclic uniaxial strain at 1 Hz for 48 h. TGFβ1 and TGFβRI inhibitor were added to selected cultures. RNA was measured using qRT-PCR and TGFβ protein levels were determined using a cell based luciferase assay. We observed that mechanical strain regulated the mRNA levels of multiple protease and matrix genes anabolically, and this regulation mirrored that seen with TGFβ stimulation alone. We have also demonstrated that the inhibition of the TGFβ signalling pathway abrogated the strain induced changes in mRNA and that TGFβ activation, rather than gene expression, was increased with mechanical strain. We concluded that TGFβ activation plays an important role in mechanotransduction. Targeting this pathway may have its place in the treatment of tendinopathy. Mechanical strain regulates multiple protease and matrix genes at the mRNA level. Changes in mRNA level are analogous to those induced by TGFβ stimulation. The inhibition of the TGFβ signalling pathway abrogated the strain-induced changes. A SMAD activatory soluble factor is increased in activity in response to mechanical load.
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Affiliation(s)
- Eleanor R Jones
- Soft Tissue Research Group, School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, UK.
| | - Gavin C Jones
- Soft Tissue Research Group, School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, UK
| | - Kirsten Legerlotz
- Soft Tissue Research Group, School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, UK
| | - Graham P Riley
- Soft Tissue Research Group, School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, UK
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43
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Lavagnino M, Gardner K, Sedlak AM, Arnoczky SP. Tendon cell ciliary length as a biomarker of in situ cytoskeletal tensional homeostasis. Muscles Ligaments Tendons J 2013; 3:118-121. [PMID: 24367770 PMCID: PMC3838319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
To determine if tendon cell ciliary length could be used as a biomarker of cytoskeletal tensional homeostasis, 20 mm long adult rat tail tendons were placed in double artery clamps set 18 mm apart to create a 10% laxity. The tendons were allowed to contract over a 7 day period under culture conditions. At 0, 1, 5, and 7 days the tendon cell cilia were stained and ciliary length measured using confocal imaging. There was a significant (p<0.001) increase in ciliary length at 1 day. At day 5 (when the tendon became visibly taut) there was a significant (p<0.001) decrease in ciliary length compared to day 1. By day 7 the tendon remained taut and ciliary length returned to day zero values (p=0.883). These results suggest that cilia length reflects the local mechanobiological environment of tendon cells and could be used as a potential in situ biomarker of altered cytoskeletal tensional homeostasis.
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Affiliation(s)
| | | | | | - Steven Paul Arnoczky
- Corresponding author: Steven Paul Arnoczky, Laboratory for Comparative Orthopaedic Research, College of Veterinary Medicine, Michigan State University, East Lansing, Michigan 48824, USA, E-mail:
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Smith DW, Rubenson J, Lloyd D, Zheng M, Fernandez J, Besier T, Xu J, Gardiner BS. A conceptual framework for computational models of Achilles tendon homeostasis. WILEY INTERDISCIPLINARY REVIEWS-SYSTEMS BIOLOGY AND MEDICINE 2013; 5:523-38. [PMID: 23757159 DOI: 10.1002/wsbm.1229] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2012] [Revised: 04/22/2013] [Accepted: 04/25/2013] [Indexed: 12/31/2022]
Abstract
Computational modeling of tendon lags the development of computational models for other tissues. A major bottleneck in the development of realistic computational models for Achilles tendon is the absence of detailed conceptual and theoretical models as to how the tissue actually functions. Without the conceptual models to provide a theoretical framework to guide the development and integration of multiscale computational models, modeling of the Achilles tendon to date has tended to be piecemeal and focused on specific mechanical or biochemical issues. In this paper, we present a new conceptual model of Achilles tendon tissue homeostasis, and discuss this model in terms of existing computational models of tendon. This approach has the benefits of structuring the research on relevant computational modeling to date, while allowing us to identify new computational models requiring development. The critically important functional issue for tendon is that it is continually damaged during use and so has to be repaired. From this follows the centrally important issue of homeostasis of the load carrying collagen fibrils within the collagen fibers of the Achilles tendon. Collagen fibrils may be damaged mechanically-by loading, or damaged biochemically-by proteases. Upon reviewing existing computational models within this conceptual framework of the Achilles tendon structure and function, we demonstrate that a great deal of theoretical and experimental research remains to be done before there are reliably predictive multiscale computational model of Achilles tendon in health and disease.
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Affiliation(s)
- David W Smith
- Faculty of Engineering, Computing, and Mathematics, The University of Western Australia, Crawley, Western Australia, Australia
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45
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Legerlotz K, Riley GP, Screen HR. GAG depletion increases the stress-relaxation response of tendon fascicles, but does not influence recovery. Acta Biomater 2013; 9:6860-6. [PMID: 23462553 PMCID: PMC3666056 DOI: 10.1016/j.actbio.2013.02.028] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Revised: 02/06/2013] [Accepted: 02/08/2013] [Indexed: 11/28/2022]
Abstract
Cyclic and static loading regimes are commonly used to study tenocyte metabolism in vitro and to improve our understanding of exercise-associated tendon pathologies. The aims of our study were to investigate if cyclic and static stress relaxation affected the mechanical properties of tendon fascicles differently, if this effect was reversible after a recovery period, and if the removal of glycosaminoglycans (GAGs) affected sample recovery. Tendon fascicles were dissected frombovine-foot extensors and subjected to 14% cyclic (1Hz) or static tensile strain for 30min. Additional fascicles were incubated overnight in buffer with 0.5U chondroitinase ABC or in buffer alone prior to the static stress-relaxation regime. To assess the effect of different stress-relaxation regimes, a quasi-static test to failure was carried out, either directly post loading or after a 2h recovery period, and compared with unloaded control fascicles. Both stress-relaxation regimes led to a significant reduction in fascicle failure stress and strain, but this was more pronounced in the cyclically loaded specimens. Removal of GAGs led to more stress relaxation and greater reductions in failure stress after static loading compared to controls. The reduction in mechanical properties was partially reversible in all samples, given a recovery period of 2h. This has implications for mechanical testing protocols, as a time delay between fatiguing specimens and characterization of mechanical properties will affect the results. GAGs appear to protect tendon fascicles from fatigue effects, possibly by enabling sample hydration.
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Affiliation(s)
- Kirsten Legerlotz
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, UK
- Institute of Bioengineering, School of Engineering and Materials Science, Queen Mary University of London, UK
- Corresponding author. Address: School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK. Tel.: +44 1603 591785; fax: +44 1603 592250. k.s.l.@gmx.de
| | - Graham P. Riley
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, UK
| | - Hazel R.C. Screen
- Institute of Bioengineering, School of Engineering and Materials Science, Queen Mary University of London, UK
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Wang T, Lin Z, Day RE, Gardiner B, Landao-Bassonga E, Rubenson J, Kirk TB, Smith DW, Lloyd DG, Hardisty G, Wang A, Zheng Q, Zheng MH. Programmable mechanical stimulation influences tendon homeostasis in a bioreactor system. Biotechnol Bioeng 2013; 110:1495-507. [PMID: 23242991 DOI: 10.1002/bit.24809] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2012] [Revised: 11/27/2012] [Accepted: 12/07/2012] [Indexed: 12/16/2022]
Abstract
Identification of functional programmable mechanical stimulation (PMS) on tendon not only provides the insight of the tendon homeostasis under physical/pathological condition, but also guides a better engineering strategy for tendon regeneration. The aims of the study are to design a bioreactor system with PMS to mimic the in vivo loading conditions, and to define the impact of different cyclic tensile strain on tendon. Rabbit Achilles tendons were loaded in the bioreactor with/without cyclic tensile loading (0.25 Hz for 8 h/day, 0-9% for 6 days). Tendons without loading lost its structure integrity as evidenced by disorientated collagen fiber, increased type III collagen expression, and increased cell apoptosis. Tendons with 3% of cyclic tensile loading had moderate matrix deterioration and elevated expression levels of MMP-1, 3, and 12, whilst exceeded loading regime of 9% caused massive rupture of collagen bundle. However, 6% of cyclic tensile strain was able to maintain the structural integrity and cellular function. Our data indicated that an optimal PMS is required to maintain the tendon homeostasis and there is only a narrow range of tensile strain that can induce the anabolic action. The clinical impact of this study is that optimized eccentric training program is needed to achieve maximum beneficial effects on chronic tendinopathy management.
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Affiliation(s)
- Tao Wang
- Centre for Orthopaedic Translational Research, School of Surgery, University of Western Australia, M Block, QE2 Medical Centre, Nedlands, Crawley, Western Australia 6009, Australia
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Lavagnino M, Gardner K, Arnoczky SP. Age-related changes in the cellular, mechanical, and contractile properties of rat tail tendons. Connect Tissue Res 2012. [PMID: 23186207 DOI: 10.3109/03008207.2012.744973] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Tendon laxity following injury, cyclic creep, or repair has been shown to alter the normal homeostasis of tendon cells, which can lead to degenerative changes in the extracellular matrix. While tendon cells have been shown to have an inherent contractile mechanism that gives them some ability to retighten lax tendons and reestablish a homeostatic cellular environment, the effect of age on this process is unknown. To determine the effect of aging on cell number, cell shape, and tensile modulus on tendons as well as the rate of cell-mediated contraction of lax tendons, tail tendon fascicles from 1-, 3-, and 12-month-old rats were analyzed. Aging results in a decrease (p < 0.001) in cell number per mm(2): 1 m (981 ± 119), 3 m (570 ± 108), and 12 m (453 ± 23), a more flattened (p < 0.001) cell nuclei shape and a higher (p < 0.001) tensile modulus (MPa) of the tendons: 1 m (291 ± 2), 3 m (527 ± 38), and 12 m (640 ± 102). Both the extent and rate of contraction over 7 days decreased with age (p = 0.007). This decrease in contraction rate with age correlates to the observed changes seen in aging tendons [increased modulus (r(2) = 0.95), decreased cell number (r(2) = 0.89)]. The ability of tendons to regain normal tension following injury or exercise-induced laxity is a key factor in the recovery of tendon function. The decreased contraction rate as a function of age observed in the current study may limit the ability of tendon cells to retighten lax tendons in older individuals. This, in turn, may place these structures at further risk for injury or altered function.
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Affiliation(s)
- Michael Lavagnino
- Laboratory for Comparative Orthopaedic Research, College of Veterinary Medicine, Michigan State University, East Lansing, MI 48824, USA
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Gardner K, Lavagnino M, Egerbacher M, Arnoczky SP. Re-establishment of cytoskeletal tensional homeostasis in lax tendons occurs through an actin-mediated cellular contraction of the extracellular matrix. J Orthop Res 2012; 30:1695-701. [PMID: 22517354 DOI: 10.1002/jor.22131] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2012] [Accepted: 03/29/2012] [Indexed: 02/04/2023]
Abstract
Cytoskeletal tensional homeostasis is known to be an important factor in controlling catabolic gene expression in tendon cells. Loss of cell tension in lax rat tail tendon fascicles (RTTfs) has been associated with an upregulation of MMP-13 gene expression and protein synthesis. To determine the role of the actin cytoskeleton in re-establishing tensional homeostasis in lax tendons, RTTfs were allowed to freely contract in vitro for 8 days. The cultured RTTfs contracted rapidly, reaching 50% of their initial length by 3 days. This contraction was associated with the presence of α-smooth muscle actin positive cells within the tendon. Disruption of the actin network by cytochalasian D caused an immediate and significant elongation of the contracted RTTfs. Subsequent removal of the cytochalasian D re-initiated the contraction process. When lax RTTfs were allowed to contract between fixed clamps in culture and become taut, they demonstrated a marked decrease in MMP-13 staining intensity when compared to freely contracting RTTfs. The ability of native tendon cells to contract lax tendons and re-establish their homeostatic "set point" with respect to collagenase production may be an important mechanism in the recovery of tendons elongated by injury, surgical positioning, or cyclic, viscoelastic creep secondary to repetitive exercise.
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Affiliation(s)
- Keri Gardner
- Laboratory for Comparative Orthopaedic Research, Michigan State University, East Lansing, MI, USA
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Abstract
Tendinosis is a troublesome clinical entity affecting many active people. Its treatment remains a challenge to sports medicine clinicians. The etiopathophysiology of tendinosis has not been well delineated. The known pathophysiology and the recent advances in the understanding of the etiologic process of tendinosis are discussed here, including new concepts in mechanotransduction and the biochemical alterations that occur during tendon overload. The optimal, nonoperative treatment of tendinosis is not clear. This article reviews recent evidence of the clinical efficacy of the following interventions: eccentric exercise, extracorporal shock wave treatment, corticosteroid and nonsteroidal anti-inflammatory medications, sclerosing injections, nitric oxide, platelet-rich plasma injections, and matrix metalloproteinase inhibitors. Eccentric exercise has strongest evidence of efficacy. Extracorporal shock wave treatment has mixed evidence and needs further study of energy and application protocols. Sclerosing agents show promising early results but require long-term studies. Corticosteroid and nonsteroidal anti-inflammatory medications have not been shown to be effective, and many basic science studies raise possible concerns with their use. Nitric oxide has been shown in several basic science studies to be promising, but clinical efficacy has not been well established. More clinical trials are needed to assess dosing, indications, and clinical efficacy of nitric oxide. Platelet-rich plasma injections have offered encouraging short-term results. Larger and longer-term clinical trials are needed to assess this promising modality. Matrix metalloproteinase inhibitors have had few clinical studies, and their role in the treatment of tendinosis is still in the early phase of investigation.
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Affiliation(s)
- Christopher Kaeding
- Address correspondence to Christopher Kaeding, MD, The Ohio State University, Sports Medicine Center, 2050 Kenny Road, Suite 3100, Columbus, OH 43221 (e-mail: )
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50
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Andarawis-Puri N, Sereysky JB, Sun HB, Jepsen KJ, Flatow EL. Molecular response of the patellar tendon to fatigue loading explained in the context of the initial induced damage and number of fatigue loading cycles. J Orthop Res 2012; 30:1327-34. [PMID: 22227881 PMCID: PMC3763927 DOI: 10.1002/jor.22059] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2011] [Accepted: 12/12/2011] [Indexed: 02/04/2023]
Abstract
Accumulation of sub-rupture fatigue damage has been implicated in the development of tendinopathy. We previously developed an in vivo model of damage accumulation using the rat patellar tendon. Our model allows us to control the input loading parameters to induce fatigue damage in the tendon. Despite this precise control, the resulting induced damage could vary among animals because of differences in size or strength among their patellar tendons. In this study, we used number of applied cycles and initial (day-0) parameters that are indicative of induced damage to assess the molecular response 7 days after fatigue loading. We hypothesized that day-0 hysteresis, elongation, and stiffness of the loading and unloading load-displacement curves would be predictive of the 7-day molecular response. Results showed correlations between the 7-day molecular response and both day-0 elongation and unloading stiffness. Additionally, loading resulted in upregulation of several extracellular matrix genes that suggest adaptation; however, several of these genes (Col-I, -XII, MMP 2, and TIMP 3) shut down after a high level of damage was induced. We showed that evaluating the 7-day molecular profile in light of day-0 elongation provides important insight that is lost from comparing number of fatigue loading cycles only. Our data showed that loading generally results in an adaptive response. However, the tendon's ability to effectively respond deteriorates as greater damage is induced.
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Affiliation(s)
- Nelly Andarawis-Puri
- Leni and Peter W. May Department of Orthopaedics, Mount Sinai School of Medicine, Mount Sinai School of Medicine, 5 East 98th Street, New York, New York 10029, USA
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