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Thomas SJ, Sarver JJ, Ebaugh DD, Paul RW, Osman A, Topley M, Soloff L, Quinlan J, Kelly JD. Chronic adaptations of the long head of the biceps tendon and groove in professional baseball pitchers. J Shoulder Elbow Surg 2022; 31:1047-1054. [PMID: 34861407 DOI: 10.1016/j.jse.2021.10.034] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Revised: 10/11/2021] [Accepted: 10/23/2021] [Indexed: 02/01/2023]
Abstract
BACKGROUND AND HYPOTHESIS The long head of the biceps tendon (LHBT) plays a significant shoulder stabilizing role during pitching, with the large forces and repetitions involved in overhead throwing likely contributing to LHBT pathology. Determining whether the LHBT undergoes adaptive changes in baseball pitchers and how these changes relate to bicipital groove morphology can improve our understanding of the biceps function at the glenohumeral joint. Therefore, the purpose of this study was to determine the chronic adaptations of the bicipital groove morphology and the LHBT in professional baseball pitchers, with a secondary purpose of evaluating biceps integrity as it relates to torsional changes of the bicipital groove. We hypothesized that the throwing arm of professional baseball pitchers would exhibit chronic adaptations of the LHBT compared with their nonthrowing arm, and that these adaptations would be related to the bicipital groove morphology. MATERIALS AND METHODS Fifty-three professional baseball pitchers were enrolled at the beginning of the 2015 Major League Baseball spring training. Ultrasound was used to bilaterally measure humeral retroversion and to capture images of the bicipital groove and the LHBT. MATLAB software was used to calculate the area of the bicipital groove, and ImageJ software was used to quantify the area, echogenicity, and circularity of the LHBT. RESULTS The dominant arm LHBT cross-sectional area was significantly smaller than the nondominant arm (9 mm2 vs. 10 mm2; P = .011), whereas the dominant arm LHBT echogenicity was significantly higher than the nondominant arm (65 optical density vs. 59 optical density; P = .002). Pitchers with more bicipital groove rotational adaptation (more retroversion) had significantly more LHBT echogenicity adaptation compared with pitchers with less bicipital groove rotational adaptation (12 vs. 2; P = .023). CONCLUSION There are significant bilateral differences in the LHBT of professional baseball pitchers. An adaptation in bony rotation was associated with a larger bilateral difference in LHBT echogenicity but was not related to bilateral differences in LHBT area or circularity. Therefore, the bilateral difference in echogenicity is impacted by bony morphology, whereas the bilateral difference in cross-sectional area may be independent of bony morphology in this healthy population.
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Affiliation(s)
- Stephen J Thomas
- College of Rehabilitation Sciences, Thomas Jefferson University, Philadelphia, PA, USA.
| | - Joseph J Sarver
- Department of Bioengineering, Drexel University, Philadelphia, PA, USA
| | - D David Ebaugh
- College of Health Sciences, University of Delaware, Newark, DE, USA
| | - Ryan W Paul
- Rothman Orthopaedic Institute, Thomas Jefferson University Hospital, Philadelphia, PA, USA
| | - Alim Osman
- Eastern Virginia Medical School, Norfolk, VA, USA
| | - Matthew Topley
- Department of Kinesiology, Temple University, Philadelphia, PA, USA
| | | | | | - John D Kelly
- Department of Orthopaedic Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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2
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Mora KE, Mlawer SJ, Bae AJ, Richards MS, Loiselle AE, Buckley MR. Ultrasound strain mapping of the mouse Achilles tendon during passive dorsiflexion. J Biomech 2022; 132:110920. [PMID: 34998182 PMCID: PMC10564406 DOI: 10.1016/j.jbiomech.2021.110920] [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: 03/18/2021] [Revised: 12/14/2021] [Accepted: 12/15/2021] [Indexed: 11/21/2022]
Abstract
Immediately prior to inserting into bone, many healthy tendons experience impingement from nearby bony structures. However, super-physiological levels of impingement are implicated in insertional tendinopathies. Unfortunately, the mechanisms underlying the connection between impingement and tendon pathology remain poorly understood, in part due to the shortage of well-characterized animal models of impingement at clinically relevant sites. As a first step towards developing a model of excessive tendon impingement, the objective of this study was to characterize the mechanical strain environment in the mouse Achilles tendon insertion under passive dorsiflexion and confirm that - like humans - mice experience impingement of the tendon insertion from the calcaneus (heel bone) in dorsiflexed ankle positions. Based on previous work in humans, we hypothesized that during dorsiflexion, the mouse Achilles tendon insertion would experience high levels of transverse compressive strain due to calcaneal impingement. A custom-built loading platform was used to apply passive dorsiflexion, while an ultrasound transducer positioned over the Achilles tendon captured radiofrequency images. A non-rigid image registration algorithm was then used to map the transverse compressive strain based on the acquired ultrasound image sequences. Our results demonstrate that during passive dorsiflexion, transverse compressive strains were produced throughout the Achilles tendon, with significantly larger strain magnitudes at the tendon insertion than at the midsubstance. Furthermore, there was increasing transverse compressive strain observed within the Achilles tendon as a function of increasing dorsiflexion angle. This study enhances our understanding of the unique mechanical loading environment of the Achilles tendon under physiologically relevant conditions.
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Affiliation(s)
- Keshia E Mora
- Department of Biomedical Engineering, University of Rochester, Rochester, NY 14620, USA; Center for Musculoskeletal Research, Department of Orthopaedics and Rehabilitation, University of Rochester Medical Center, Rochester, NY 14620, USA.
| | - Samuel J Mlawer
- Department of Biomedical Engineering, University of Rochester, Rochester, NY 14620, USA; Center for Musculoskeletal Research, Department of Orthopaedics and Rehabilitation, University of Rochester Medical Center, Rochester, NY 14620, USA
| | - Albert J Bae
- Department of Biomedical Engineering, University of Rochester, Rochester, NY 14620, USA; Center for Musculoskeletal Research, Department of Orthopaedics and Rehabilitation, University of Rochester Medical Center, Rochester, NY 14620, USA
| | - Michael S Richards
- Department of Biomedical Engineering, Rochester Institute of Technology, Rochester, NY 14623, USA
| | - Alayna E Loiselle
- Department of Biomedical Engineering, University of Rochester, Rochester, NY 14620, USA; Center for Musculoskeletal Research, Department of Orthopaedics and Rehabilitation, University of Rochester Medical Center, Rochester, NY 14620, USA
| | - Mark R Buckley
- Department of Biomedical Engineering, University of Rochester, Rochester, NY 14620, USA; Center for Musculoskeletal Research, Department of Orthopaedics and Rehabilitation, University of Rochester Medical Center, Rochester, NY 14620, USA
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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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4
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Chimenti RL, Bucklin M, Kelly M, Ketz J, Flemister AS, Richards MS, Buckley MR. Insertional achilles tendinopathy associated with altered transverse compressive and axial tensile strain during ankle dorsiflexion. J Orthop Res 2017; 35:910-915. [PMID: 27306527 PMCID: PMC5738911 DOI: 10.1002/jor.23338] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Accepted: 06/14/2016] [Indexed: 02/04/2023]
Abstract
The purposes of this case-control study (N = 20) were to examine the effects of insertional Achilles tendinopathy (IAT) and tendon region on tendon strain in patients with IAT compared to a control group without tendinopathy. An ultrasound transducer was positioned over the Achilles tendon insertion during dorsiflexion tasks, which included standing and partial squat. A non-rigid image registration-based algorithm was used to estimate transverse compressive and axial tensile strains of the tendon from radiofrequency ultrasound images, which was segmented into two regions (superficial tendon and deep). For transverse compressive strain, two-way mixed effects ANOVAs demonstrated that there were interaction effects between group and tendon region for both dorsiflexion tasks (Heel lowering, p = 0.004; Partial squat, p = 0.008). For axial tensile strain, the IAT group demonstrated a main effect of lower tensile strain than the control group (Standing, p = 0.001; Partial squat, p = 0.033). There was also a main effect of greater tensile strain in the superficial region of the tendon compared to the deep during standing (p = 0.002), but not during partial squat (p = 0.603). Reduced transverse compressive and axial tensile strains in the IAT group indicate altered mechanical properties specific to the region of IAT pathology. Additionally, patterns of compressive strain are consistent with the theory of calcaneal impingement contributing to IAT pathology. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:910-915, 2017.
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Affiliation(s)
- Ruth L Chimenti
- Post-doctoral fellow, University of Iowa, Department of Physical Therapy and Rehabilitation Science
| | - Mary Bucklin
- Student, University of Rochester, Department of Biomedical Engineering
| | - Meghan Kelly
- Resident, University of Rochester, Department of Orthopaedic Surgery
| | - John Ketz
- Assistant Professor, University of Rochester, Department of Orthopaedic Surgery
| | - A. Samuel Flemister
- Associate Professor, University of Rochester, Department of Orthopaedic Surgery
| | - Michael S. Richards
- Research Assistant Professor, University of Rochester, Department of Surgery
| | - Mark R Buckley
- Assistant Professor, University of Rochester, Department of Biomedical Engineering
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Berglund M, Wiig M, Torstensson M, Reno C, Hart DA. Assessment of mRNA Levels for Matrix Molecules and TGF-β1 in Rabbit Flexor and Peroneus Tendons Reveals Regional Differences in Steady-State Expression. ACTA ACUST UNITED AC 2016; 29:165-9. [PMID: 15010165 DOI: 10.1016/j.jhsb.2003.09.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2002] [Accepted: 09/04/2003] [Indexed: 10/26/2022]
Abstract
This study analysed the differences on a molecular level between two segments of the deep flexor tendon, and compared the intrasynovial flexor tendon with the tendon sheath and the extrasynovial peroneus tendon in a rabbit model. The TRIspin method of RNA extraction was combined with the reverse transcription polymerase chain reaction to assess mRNA levels in the tissue segments. Significant differences were detected for all genes studied. mRNA levels for aggrecan, biglycan and collagen III were significantly higher in the fibrocartilaginous proximal segment of the flexor tendon. Collagen I was higher in the flexor tendon than the sheath and the peroneus tendon, and TGF-β1 was significantly lower in the peroneus tendon. This study demonstrates differences at the mRNA level between different segments of tendon, indicating that the tendon tissue may be adapted to its environment.
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Affiliation(s)
- M Berglund
- Department of Hand Surgery, Uppsala University Hospital, Uppsala, Sweden and McCaig Centre for Joint Injury and Arthritis Research, University of Calgary, Canada
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Han WM, Heo SJ, Driscoll TP, Delucca JF, McLeod CM, Smith LJ, Duncan RL, Mauck RL, Elliott DM. Microstructural heterogeneity directs micromechanics and mechanobiology in native and engineered fibrocartilage. NATURE MATERIALS 2016; 15:477-84. [PMID: 26726994 PMCID: PMC4805445 DOI: 10.1038/nmat4520] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2015] [Accepted: 11/24/2015] [Indexed: 05/05/2023]
Abstract
Treatment strategies to address pathologies of fibrocartilaginous tissue are in part limited by an incomplete understanding of structure-function relationships in these load-bearing tissues. There is therefore a pressing need to develop micro-engineered tissue platforms that can recreate the highly inhomogeneous tissue microstructures that are known to influence mechanotransductive processes in normal and diseased tissue. Here, we report the quantification of proteoglycan-rich microdomains in developing, ageing and diseased fibrocartilaginous tissues, and the impact of these microdomains on endogenous cell responses to physiologic deformation within a native-tissue context. We also developed a method to generate heterogeneous tissue-engineered constructs (hetTECs) with non-fibrous proteoglycan-rich microdomains engineered into the fibrous structure, and show that these hetTECs match the microstructural, micromechanical and mechanobiological benchmarks of native tissue. Our tissue-engineered platform should facilitate the study of the mechanobiology of developing, homeostatic, degenerating and regenerating fibrous tissues.
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Affiliation(s)
- Woojin M Han
- Department of Bioengineering, University of Pennsylvania
| | - Su-Jin Heo
- Department of Bioengineering, University of Pennsylvania
- Department of Orthopaedic Surgery, Perelman School of Medicine, University of Pennsylvania
| | - Tristan P Driscoll
- Department of Bioengineering, University of Pennsylvania
- Department of Orthopaedic Surgery, Perelman School of Medicine, University of Pennsylvania
| | - John F Delucca
- Department of Biomedical Engineering, University of Delaware
| | - Claire M McLeod
- Department of Bioengineering, University of Pennsylvania
- Department of Orthopaedic Surgery, Perelman School of Medicine, University of Pennsylvania
| | - Lachlan J Smith
- Department of Orthopaedic Surgery, Perelman School of Medicine, University of Pennsylvania
- Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania
| | - Randall L Duncan
- Department of Biomedical Engineering, University of Delaware
- Department of Biological Sciences, University of Delaware
| | - Robert L Mauck
- Department of Bioengineering, University of Pennsylvania
- Department of Orthopaedic Surgery, Perelman School of Medicine, University of Pennsylvania
- Addresses for Correspondence: Dawn M. Elliott, Ph.D., Professor and Director of Biomedical Engineering, Department of Biomedical Engineering, University of Delaware, 161 Colburn Laboratory, Newark, DE 19716, Phone: (302) 831-4578, . Robert L. Mauck, Ph.D., Associate Professor of Orthopaedic Surgery and Bioengineering, Director, McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, Perelman School of Medicine, University of Pennsylvania, 36 Street and Hamilton Walk, Philadelphia, PA 19104, Phone: (215) 898-3294,
| | - Dawn M Elliott
- Department of Biomedical Engineering, University of Delaware
- Addresses for Correspondence: Dawn M. Elliott, Ph.D., Professor and Director of Biomedical Engineering, Department of Biomedical Engineering, University of Delaware, 161 Colburn Laboratory, Newark, DE 19716, Phone: (302) 831-4578, . Robert L. Mauck, Ph.D., Associate Professor of Orthopaedic Surgery and Bioengineering, Director, McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, Perelman School of Medicine, University of Pennsylvania, 36 Street and Hamilton Walk, Philadelphia, PA 19104, Phone: (215) 898-3294,
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7
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Engineering Tendon: Scaffolds, Bioreactors, and Models of Regeneration. Stem Cells Int 2015; 2016:3919030. [PMID: 26839559 PMCID: PMC4709784 DOI: 10.1155/2016/3919030] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2015] [Accepted: 09/20/2015] [Indexed: 12/23/2022] Open
Abstract
Tendons bridge muscle and bone, translating forces to the skeleton and increasing the safety and efficiency of locomotion. When tendons fail or degenerate, there are no effective pharmacological interventions. The lack of available options to treat damaged tendons has created a need to better understand and improve the repair process, particularly when suitable autologous donor tissue is unavailable for transplantation. Cells within tendon dynamically react to loading conditions and undergo phenotypic changes in response to mechanobiological stimuli. Tenocytes respond to ultrastructural topography and mechanical deformation via a complex set of behaviors involving force-sensitive membrane receptor activity, changes in cytoskeletal contractility, and transcriptional regulation. Effective ex vivo model systems are needed to emulate the native environment of a tissue and to translate cell-matrix forces with high fidelity. While early bioreactor designs have greatly expanded our knowledge of mechanotransduction, traditional scaffolds do not fully model the topography, composition, and mechanical properties of native tendon. Decellularized tendon is an ideal scaffold for cultivating replacement tissue and modeling tendon regeneration. Decellularized tendon scaffolds (DTS) possess high clinical relevance, faithfully translate forces to the cellular scale, and have bulk material properties that match natural tissue. This review summarizes progress in tendon tissue engineering, with a focus on DTS and bioreactor systems.
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8
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Bah I, Kwak ST, Chimenti RL, Richards MS, P Ketz J, Samuel Flemister A, Buckley MR. Mechanical changes in the Achilles tendon due to insertional Achilles tendinopathy. J Mech Behav Biomed Mater 2015; 53:320-328. [PMID: 26386166 DOI: 10.1016/j.jmbbm.2015.08.022] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Revised: 07/31/2015] [Accepted: 08/11/2015] [Indexed: 11/24/2022]
Abstract
Insertional Achilles tendinopathy (IAT) is a painful and debilitating condition that responds poorly to non-surgical interventions. It is thought that this disease may originate from compression of the Achilles tendon due to calcaneal impingement. Thus, compressive mechanical changes associated with IAT may elucidate its etiology and offer clues to guide effective treatment. However, the mechanical properties of IAT tissue have not been characterized. Therefore, the objective of this study was to measure the mechanical properties of excised IAT tissue and compare with healthy cadaveric control tissue. Tissue from the Achilles tendon insertion was acquired from healthy donors and from patients undergoing debridement surgery for IAT. Several tissue specimens from each donor were then mechanically tested under cyclic unconfined compression and the acquired data was analyzed to determine the distribution of mechanical properties for each donor. While the median mechanical properties of tissue excised from IAT tendons were not significantly different than healthy tissue, the distribution of mechanical properties within each donor was dramatically altered. In particular, healthy tendons contained more low modulus (compliant) and high transition strain specimens than IAT tendons, as evidenced by a significantly lower 25th percentile secant modulus and higher 75th percentile transition strain. Furthermore, these parameters were significantly correlated with symptom severity. Finally, it was found that preconditioning and slow loading both reduced the secant modulus of healthy and IAT specimens, suggesting that slow, controlled ankle dorsiflexion prior to activity may help IAT patients manage disease-associated pain.
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Affiliation(s)
- Ibrahima Bah
- University of Rochester, Department of Biomedical Engineering, United States.
| | - Samuel T Kwak
- University of Rochester, Department of Biomedical Engineering, United States
| | - Ruth L Chimenti
- University of Rochester, Department of Biomedical Engineering, United States
| | | | - John P Ketz
- University of Rochester, Department of Orthopaedics, United States
| | | | - Mark R Buckley
- University of Rochester, Department of Biomedical Engineering, United States
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Shinohara Y, Kumai T, Higashiyama I, Hayashi K, Matsuda T, Tanaka Y, Takakura Y. Histological and molecular characterization of the femoral attachment of the human ligamentum capitis femoris. Scand J Med Sci Sports 2013; 24:e245-53. [DOI: 10.1111/sms.12155] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/22/2013] [Indexed: 11/30/2022]
Affiliation(s)
- Y. Shinohara
- Department of Orthopaedic Surgery; Nara Medical University; Nara Japan
| | - T. Kumai
- Department of Orthopaedic Surgery; Nara Medical University; Nara Japan
| | - I. Higashiyama
- Department of Orthopaedic Surgery; Nara Medical University; Nara Japan
| | - K. Hayashi
- Department of Orthopaedic Surgery; Nara Medical University; Nara Japan
| | - T. Matsuda
- Department of Orthopaedic Surgery; Nara Medical University; Nara Japan
| | - Y. Tanaka
- Department of Orthopaedic Surgery; Nara Medical University; Nara Japan
| | - Y. Takakura
- Department of Orthopaedic Surgery; Nara Medical University; Nara Japan
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Butler DL, Dyment NA, Shearn JT, Kinneberg KRC, Breidenbach AP, Lalley AL, Gilday SD, Gooch C, Rao MB, Liu CF, Wylie C. Evolving strategies in mechanobiology to more effectively treat damaged musculoskeletal tissues. J Biomech Eng 2013; 135:020301. [PMID: 23445046 DOI: 10.1115/1.4023479] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
In this paper, we had four primary objectives. (1) We reviewed a brief history of the Lissner award and the individual for whom it is named, H.R. Lissner. We examined the type (musculoskeletal, cardiovascular, and other) and scale (organism to molecular) of research performed by prior Lissner awardees using a hierarchical paradigm adopted at the 2007 Biomechanics Summit of the US National Committee on Biomechanics. (2) We compared the research conducted by the Lissner award winners working in the musculoskeletal (MS) field with the evolution of our MS research and showed similar trends in scale over the past 35 years. (3) We discussed our evolving mechanobiology strategies for treating musculoskeletal injuries by accounting for clinical, biomechanical, and biological considerations. These strategies included studies to determine the function of the anterior cruciate ligament and its graft replacements as well as novel methods to enhance soft tissue healing using tissue engineering, functional tissue engineering, and, more recently, fundamental tissue engineering approaches. (4) We concluded with thoughts about future directions, suggesting grand challenges still facing bioengineers as well as the immense opportunities for young investigators working in musculoskeletal research. Hopefully, these retrospective and prospective analyses will be useful as the ASME Bioengineering Division charts future research directions.
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Affiliation(s)
- David L Butler
- Tissue Engineering and Biomechanics Laboratories, Biomedical Engineering Program, College of Engineering and Applied Sciences, University of Cincinnati; Cincinnati, OH 45221, USA.
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11
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The upper band of the subscapularis tendon in the rat has altered mechanical and histologic properties. J Shoulder Elbow Surg 2012; 21:1687-93. [PMID: 22484390 PMCID: PMC3393832 DOI: 10.1016/j.jse.2011.11.038] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2011] [Revised: 11/14/2011] [Accepted: 11/28/2011] [Indexed: 02/01/2023]
Abstract
BACKGROUND The subscapularis is an important mover and stabilizer of the glenohumeral joint. Since the advent of shoulder arthroscopy, partial tears are found in 43% of rotator cuff patients. While partial tears to the upper band occur more commonly, little is known about the structure and mechanical behavior of the individual bands. Therefore, the objective of this study was to measure tensile mechanical properties, corresponding collagen fiber alignment, and histology in the upper and lower bands of the rat subscapularis tendon. MATERIALS AND METHODS Thirty adult Sprague-Dawley rats were euthanized and subscapularis tendons dissected out for mechanical organization (n = 24) and histologic assessment (n = 6). Collagen organization was measured with a custom device during mechanical testing. RESULTS Linear-region modulus at the insertion site was significantly lower in the upper band compared to the lower band, while no differences were found at the midsubstance location. The upper band was found to be significantly less aligned and demonstrated a more rounded cell shape than the lower band at the insertion site. DISCUSSION This study demonstrated that the 2 bands of the subscapularis tendon have differential mechanical, organizational, and histological properties, which suggests a functional deficit exists to the upper band of the subscapularis and may be contributing to the prevalence of partial subscapularis tears. CONCLUSIONS Clinicians should be aware that the upper band of the subscapularis tendon may be at higher risk of developing tears, based on decreased mechanical properties and a more disorganized collagen fiber distribution.
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12
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Sun YL, Thoreson AR, Cha SS, Zhao C, An KN, Amadio PC. Temporal response of canine flexor tendon to limb suspension. J Appl Physiol (1985) 2010; 109:1762-8. [PMID: 20947711 DOI: 10.1152/japplphysiol.00051.2010] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Tendon disuse, or stress deprivation, frequently accompanies clinical disorders and treatments, yet the metabolism of tendons subject to stress deprivation has rarely been investigated systematically. The effects of stress deprivation on canine flexor tendon were investigated in this study. One adult canine forepaw was suspended for 21 or 42 days. Control forepaws were collected from dogs that had no intervention on their limbs and paws. The expression of collagen I and III was not significantly altered in the tendons disused for 21 days but was significantly decreased at 42 days (P < 0.03). The expression of collagen II, aggrecan, decorin, and fibronectin was significantly decreased in the tendons in the suspended limbs at 21 days (P < 0.002) and further reduced at 42 days. With stress deprivation, the expression of matrix metalloproteinase 2 (MMP2) was significantly increased (P < 0.004) at 21 and 42 days. The expression of MMP3 was significantly decreased at 21 and 42 days (P < 0.03). The expression of MMP13 was not altered with stress deprivation at 21 and 42 days. The expression of MMP14 was significantly increased at 21 days (P = 0.0015) and returned to the control level at 42 days. Tissue inhibitor of metalloproteinase 1 (TIMP1) expression was decreased after the limbs were suspended for 42 days (P = 0.0043), but not 21 days. However, TIMP2 expression was not significantly different from control at 21 or 42 days. Furthermore, the cross-sectional area of the stress-deprived tendons at 42 days was decreased compared with the control group (P < 0.01). The intervention method in this study did not result in any alteration of stiffness of the tendon. Our study demonstrated that stress deprivation decreases the anabolic process and increases the catabolic process of extracellular matrix in flexor tendon.
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Affiliation(s)
- Yu-Long Sun
- Biomechanics Laboratory, Mayo Clinic, 200 First St., Rochester, MN 55905, USA.
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Bosch G, Lin YL, van Schie HTM, van De Lest CHA, Barneveld A, van Weeren PR. Effect of extracorporeal shock wave therapy on the biochemical composition and metabolic activity of tenocytes in normal tendinous structures in ponies. Equine Vet J 2010; 39:226-31. [PMID: 17520973 DOI: 10.2746/042516407x180408] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
REASONS FOR PERFORMING STUDY Extracorporeal shockwave therapy (ESWT) has recently been introduced as a new therapy for tendon injuries in horses, but little is known about the basic mechanism of action of this therapy. OBJECTIVES To study the effect of ESWT on biochemical parameters and tenocyte metabolism of normal tendinous structures in ponies. METHODS Six Shetland ponies, free of lameness and with ultrasonographically normal flexor and extensor tendons and suspensory ligaments (SL), were used. ESWT was applied at the origin of the suspensory ligament and the mid-metacarpal region of the superficial digital flexor tendon (SDFT) 6 weeks prior to sample taking, and at the mid-metacarpal region (ET) and the insertion on the extensor process of the distal phalanx (EP) of the common digital extensor tendon 3 h prior to tendon sampling. In all animals one front leg was treated and the other front leg was used as control. After euthanasia, tendon explants were harvested aseptically for in vitro cell culture experiments and additional samples were taken for biochemical analyses. RESULTS In the explants harvested 3 h after treatment, glycosaminoglycan (GAG) and protein syntheses were increased (P<0.05). The synthesis of all measured parameters was decreased 6 weeks after ESWT treatment. Biochemically, the level of degraded collagen was increased 3 h after treatment (P<0.05). Six weeks after treatment, there was a decrease of degraded collagen and GAG contents. DNA content had not changed in either tendon samples or explants after culturing. CONCLUSIONS ESWT causes a transient stimulation of metabolism in tendinous structures of ponies shortly after treatment. After 6 weeks metabolism has decreased significantly and GAG levels are lower than in untreated control limbs. POTENTIAL RELEVANCE The stimulating short-term effect of ESWT might accelerate the initiation of the healing process in injured tendons. The long-term effect seems less beneficial. Further research should aim at determining the duration of this effect and at assessing its relevance for end-stage tendon quality.
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Affiliation(s)
- G Bosch
- Department of Equine Sciences, Faculty of Veterinary Medicine, Utrecht
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14
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Crockett RJ, Centrella M, McCarthy TL, Grant Thomson J. Effects of cyclic strain on rat tail tenocytes. Mol Biol Rep 2009; 37:2629-34. [DOI: 10.1007/s11033-009-9788-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2009] [Accepted: 08/31/2009] [Indexed: 11/24/2022]
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15
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Murphy KD, Mushkudiani IA, Kao D, Levesque AY, Hawkins HK, Gould LJ. Successful incorporation of tissue-engineered porcine small-intestinal submucosa as substitute flexor tendon graft is mediated by elevated TGF-beta1 expression in the rabbit. J Hand Surg Am 2008; 33:1168-78. [PMID: 18762114 DOI: 10.1016/j.jhsa.2008.02.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2007] [Revised: 02/01/2008] [Accepted: 02/04/2008] [Indexed: 02/02/2023]
Abstract
PURPOSE Ideal tendon repair materials combine minimal donor-site morbidity and ready availability with excellent healing and postoperative function. Bioengineered porcine small-intestinal submucosa (SIS) was compared with tendon autografts as a potential human flexor tendon graft substitute. METHODS Rabbit zone II flexor digitorum profundus segments were excised in 40 rabbits. Randomized tendon repair consisted of either interposition reversed autograft or SIS, passed beneath the A2 and A4 pulleys. Forepaws were statically splinted for 3 weeks followed by unrestricted motion. Animals were killed at 7, 14, 28, and 56 days. Specimens were analyzed for hydroxyproline content (absorption spectroscopy) and tensile strength. Hematoxylin-eosin and Movat-stained sections of the central graft and distal repair site were semiquantitatively scored for total cellularity, inflammatory cell content, foreign-body reaction, vascularity, mature collagen content, and new collagen deposition. Transforming growth factor-beta (TGF-beta1) and TGF-beta1 receptor immunostaining was performed. RESULTS At week 1, SIS hydroxyproline content was significantly reduced compared with autograft hydroxyproline content. However, week 2 SIS hydroxyproline content increased to equivalent values. Collagen deposition was evident in SIS by week 1 but negligible in autograft. More rapid total and inflammatory cell increases occurred in SIS by 4 weeks. A stronger early inflammatory reaction also occurred. More rapid SIS neovascularization occurred despite a greater foreign-body reaction. Small-intestinal submucosa vascularity was markedly greater at weeks 1 and 2 and equivalent thereafter. At week 4, SIS intrinsic tensile strength (suture removed) exceeded that of both autograft and suture material. Preoperative TGF-beta1 immunostaining in SIS was less than that of autograft but greater during weeks 2 and 4. CONCLUSIONS Earlier neovascularization, increased TGF-beta1 levels, and increased collagen deposition, along with greater intrinsic repair strength relative to both autograft and suture strength at week 4, make SIS a promising flexor tendon graft substitute. Future studies examining tendon excursion are planned.
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Affiliation(s)
- Kevin D Murphy
- Northern Ireland Plastic & Maxillofacial Service, Department of Plastic Surgery, The Ulster Hospital, Belfast, Northern Ireland, United Kingdom
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16
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Spalazzi JP, Vyner MC, Jacobs MT, Moffat KL, Lu HH. Mechanoactive scaffold induces tendon remodeling and expression of fibrocartilage markers. Clin Orthop Relat Res 2008; 466:1938-48. [PMID: 18512112 PMCID: PMC2584247 DOI: 10.1007/s11999-008-0310-8] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/05/2007] [Accepted: 05/05/2008] [Indexed: 01/31/2023]
Abstract
Biological fixation of soft tissue-based grafts for anterior cruciate ligament (ACL) reconstruction poses a major clinical challenge. The ACL integrates with subchondral bone through a fibrocartilage enthesis, which serves to minimize stress concentrations and enables load transfer between two distinct tissue types. Functional integration thus requires the reestablishment of this fibrocartilage interface on reconstructed ACL grafts. We designed and characterized a novel mechanoactive scaffold based on a composite of poly-alpha-hydroxyester nanofibers and sintered microspheres; we then used the scaffold to test the hypothesis that scaffold-induced compression of tendon grafts would result in matrix remodeling and the expression of fibrocartilage interface-related markers. Histology coupled with confocal microscopy and biochemical assays were used to evaluate the effects of scaffold-induced compression on tendon matrix collagen distribution, cellularity, proteoglycan content, and gene expression over a 2-week period. Scaffold contraction resulted in over 15% compression of the patellar tendon graft and upregulated the expression of fibrocartilage-related markers such as Type II collagen, aggrecan, and transforming growth factor-beta3 (TGF-beta3). Additionally, proteoglycan content was higher in the compressed tendon group after 1 day. The data suggest the potential of a mechanoactive scaffold to promote the formation of an anatomic fibrocartilage enthesis on tendon-based ACL reconstruction grafts.
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Affiliation(s)
- Jeffrey P. Spalazzi
- Department of Biomedical Engineering, Biomaterials and Interface Tissue Engineering Laboratory, Columbia University, 351 Engineering Terrace Building, MC 8904, 1210 Amsterdam Avenue, New York, NY 10027 USA
| | - Moira C. Vyner
- Department of Biomedical Engineering, Biomaterials and Interface Tissue Engineering Laboratory, Columbia University, 351 Engineering Terrace Building, MC 8904, 1210 Amsterdam Avenue, New York, NY 10027 USA
| | - Matthew T. Jacobs
- Department of Biomedical Engineering, Biomaterials and Interface Tissue Engineering Laboratory, Columbia University, 351 Engineering Terrace Building, MC 8904, 1210 Amsterdam Avenue, New York, NY 10027 USA
| | - Kristen L. Moffat
- Department of Biomedical Engineering, Biomaterials and Interface Tissue Engineering Laboratory, Columbia University, 351 Engineering Terrace Building, MC 8904, 1210 Amsterdam Avenue, New York, NY 10027 USA
| | - Helen H. Lu
- Department of Biomedical Engineering, Biomaterials and Interface Tissue Engineering Laboratory, Columbia University, 351 Engineering Terrace Building, MC 8904, 1210 Amsterdam Avenue, New York, NY 10027 USA
- College of Dental Medicine, Columbia University, New York, NY USA
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17
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Couppé C, Kongsgaard M, Aagaard P, Hansen P, Bojsen-Moller J, Kjaer M, Magnusson SP. Habitual loading results in tendon hypertrophy and increased stiffness of the human patellar tendon. J Appl Physiol (1985) 2008; 105:805-10. [PMID: 18556433 DOI: 10.1152/japplphysiol.90361.2008] [Citation(s) in RCA: 186] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The purpose of this study was to examine patellar tendon (PT) size and mechanical properties in subjects with a side-to-side strength difference of > or =15% due to sport-induced loading. Seven elite fencers and badminton players were included. Cross-sectional area (CSA) of the PT obtained from MRI and ultrasonography-based measurement of tibial and patellar movement together with PT force during isometric contractions were used to estimate mechanical properties of the PT bilaterally. We found that distal tendon and PT, but not mid-tendon, CSA were greater on the lead extremity compared with the nonlead extremity (distal: 139 +/- 11 vs. 116 +/- 7 mm(2); mid-tendon: 85 +/- 5 vs. 77 +/- 3 mm(2); proximal: 106 +/- 7 vs. 83 +/- 4 mm(2); P < 0.05). Distal tendon CSA was greater than proximal and mid-tendon CSA on both the lead and nonlead extremity (P < 0.05). For a given common force, stress was lower on the lead extremity (52.9 +/- 4.8 MPa) compared with the nonlead extremity (66.0 +/- 8.0 MPa; P < 0.05). PT stiffness was also higher in the lead extremity (4,766 +/- 716 N/mm) compared with the nonlead extremity (3,494 +/- 446 N/mm) (P < 0.05), whereas the modulus did not differ (lead 2.27 +/- 0.27 GPa vs. nonlead 2.16 +/- 0.28 GPa) at a common force. These data show that a habitual loading is associated with a significant increase in PT size and mechanical properties.
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Affiliation(s)
- C Couppé
- Institute of Sports Medicine Copenhagen, Bispebjerg Hospital Bispebjerg bakke 23, 2400 Copenhagen NV, Denmark
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18
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Benjamin M, Milz S, Bydder GM. Magnetic resonance imaging of entheses. Part 1. Clin Radiol 2008; 63:691-703. [PMID: 18455562 DOI: 10.1016/j.crad.2007.12.011] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2007] [Revised: 11/16/2007] [Accepted: 12/17/2007] [Indexed: 12/21/2022]
Abstract
Entheses are the sites of attachment of a tendon, ligament, or joint capsule to bone. Many features of entheses are adapted to disperse stress and accommodate compressive and shear forces at, or near, boundaries between tendons or ligaments and bone. Of particular interest is calcified and uncalcified fibrocartilage, which has mechanical properties that differ from those of tensile regions of tendons or ligaments, and from bone. Ultrashort echo time (UTE) pulse sequences can identify the specific tissue components of entheses and differentiate cortical bone, calcified fibrocartilage, uncalcified fibrocartilage, and fibrous connective tissue. Magic angle imaging can also differentiate tissues, such as fibrocartilage and tendon, which have different fibre orientations. Understanding the magnetic resonance (MR) appearance of entheses involves consideration of tissue properties, fibre-to-field angle, magic angle effects, pulse sequences, and geometrical factors including fibre-to-section orientation and partial volume effects. New approaches using MR imaging, allow entheses to be visualised with much greater detail than previously possible, and this may help in biomechanical studies, diagnosis of disease including overuse syndromes and spondyloarthropathies, as well as monitoring tissue repair and healing.
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Affiliation(s)
- M Benjamin
- School of Biosciences, Cardiff University, Cardiff, UK
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19
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Scott A, Lian Ø, Roberts CR, Cook JL, Handley CJ, Bahr R, Samiric T, Ilic MZ, Parkinson J, Hart DA, Duronio V, Khan KM. Increased versican content is associated with tendinosis pathology in the patellar tendon of athletes with jumper's knee. Scand J Med Sci Sports 2007; 18:427-35. [PMID: 18067512 DOI: 10.1111/j.1600-0838.2007.00735.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Expansion of the extracellular matrix is a prominent but poorly characterized feature of tendinosis. The present study aimed to characterize the extent and distribution of the large aggregating proteoglycan versican in patients with patellar tendinosis. We obtained tendon from tendinopathy patients undergoing debridement of the patellar tendon and from controls undergoing intramedullary tibial nailing. Versican content was investigated by Western blotting and immunohistochemistry. Microvessel thickness and density were determined using computer-assisted image analysis. Markers for smooth muscle actin, endothelial cells (CD31) and proliferating cells (Ki67) were examined immunohistochemically. Western blot analysis and immunohistochemical staining revealed elevated versican content in the proximal patellar tendon of tendinosis patients (P=0.042). Versican content was enriched in regions of fibrocartilage metaplasia and fibroblast proliferation, as well as in the perivascular matrix of proliferating microvessels and within the media and intima of arterioles. Microvessel density was higher in tendinosis tissue compared with control tissue. Versican deposition is a prominent feature of patellar tendinosis. Because this molecule is not only a component of normal fibrocartilagenous matrices but also implicated in a variety of soft tissue pathologies, future studies should further detail both pathological and adaptive roles of versican in tendons.
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Affiliation(s)
- A Scott
- Department of Medicine, University of British Columbia, Vancouver, BC, Canada
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20
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Kongsgaard M, Reitelseder S, Pedersen TG, Holm L, Aagaard P, Kjaer M, Magnusson SP. Region specific patellar tendon hypertrophy in humans following resistance training. Acta Physiol (Oxf) 2007; 191:111-21. [PMID: 17524067 DOI: 10.1111/j.1748-1716.2007.01714.x] [Citation(s) in RCA: 247] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
AIM To examine if cross-sectional area (CSA) differs along the length of the human patellar tendon (PT), and if there is PT hypertrophy in response to resistance training. METHODS Twelve healthy young men underwent baseline and post-training assessments. Maximal isometric knee extension strength (MVC) was determined unilaterally in both legs. PT CSA was measured at the proximal-, mid- and distal PT level and quadriceps muscle CSA was measured at mid-thigh level using magnetic resonance imaging. Mechanical properties of the patellar tendons were determined using ultrasonography. Subsequently, subjects performed 12 weeks of heavy resistance knee extension training with one leg (Heavy-leg), and light resistance knee extension training with the other leg (Light-leg). RESULTS The MVC increased for heavy-leg (15 +/- 4%, P < 0.05), but not for light-leg (6 +/- 4%). Quadriceps CSA increased in heavy-legs (6 +/- 1%, P < 0.05) while unchanged in light-legs. Proximal PT CSA (104 +/- 4 mm(2)) was smaller than the mid-tendon CSA (118 +/- 3 mm(2)), which again was smaller than distal tendon CSA (127 +/- 2 mm(2), P < 0.05). Light-leg PT CSA increased by 7 +/- 3% (P < 0.05) at the proximal tendon level, but was otherwise unchanged. Heavy-leg PT CSA increased at the proximal and distal tendon levels by 6 +/- 3% and 4 +/- 2% respectively (P < 0.05), but was unchanged at the mid tendon level. PT stiffness increased in heavy-legs (P < 0.05) but was unchanged in light-legs. Modulus remained unchanged in both legs. CONCLUSIONS To our knowledge, this study is the first to report tendon hypertrophy following resistance training. Further, the data show that the human PT CSA varies along the length of the tendon.
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Affiliation(s)
- M Kongsgaard
- Institute of Sports Medicine Copenhagen, Bispebjerg Hospital, Copenhagen, Denmark.
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21
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Nakama LH, King KB, Abrahamsson S, Rempel DM. Effect of repetition rate on the formation of microtears in tendon in an in vivo cyclical loading model. J Orthop Res 2007; 25:1176-84. [PMID: 17516500 PMCID: PMC2637381 DOI: 10.1002/jor.20408] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
We reported previously the formation of microtears in an in vivo loaded Flexor Digitorum Profundus (FDP) rabbit tendon with a repetition rate of 60 repetitions per minute and a peak force of 15% of maximum peak tetanic force for 80 cumulative hours. Tear area as a percent of tendon area, tear density (tears/mm(2)), and mean tear size (microm(2)) were higher in tendons from the loaded limb compared to the unloaded control limb. The purpose of the present study was to compare those results to results obtained with a repetition rate of 10 while maintaining the same peak force and force-time integral (n = 8). Due to a strain gradient between the inner and outer sides of the FDP tendon, microtears were quantified in four regions, two regions each along the inner and outer sides of the tendon. The tear area as a percent of total tendon area and the mean tear size were significantly greater in the loaded limb compared to the unloaded limb (p < 0.03). However, the effects were less than those observed at 60 repetitions/min. The higher repetition loading pattern resulted in an increase in tear measures in all four regions, while the lower rate produced changes only in the outer regions of the tendon. This finding may establish where the initial sites of damage occur in tendons that insert into bone in a similar arrangement as the FDP. The results suggest that repetition rate or number of loading cycles is associated with increased tendon microtears or fragility in a dose-response pattern.
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Affiliation(s)
- Leena H. Nakama
- University of California, Berkeley
- San Francisco, Joint Graduate Group in Bioengineering
| | - Karen B. King
- University of California, Berkeley
- San Francisco, Joint Graduate Group in Bioengineering
- Department of Medicine, University of California, San Francisco
| | - Sven Abrahamsson
- Department of Hand Surgery, Malmo University Hospital, Malmo, Sweden
| | - David M. Rempel
- University of California, Berkeley
- San Francisco, Joint Graduate Group in Bioengineering
- Department of Medicine, University of California, San Francisco
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22
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Westh E, Kongsgaard M, Bojsen-Moller J, Aagaard P, Hansen M, Kjaer M, Magnusson SP. Effect of habitual exercise on the structural and mechanical properties of human tendon, in vivo, in men and women. Scand J Med Sci Sports 2007; 18:23-30. [PMID: 17490462 DOI: 10.1111/j.1600-0838.2007.00638.x] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We examined whether long-term habitual training (a) was associated with differences in structural and mechanical properties in tendon in women and (b) yielded different tendon properties in men and women. Ten male runners, 10 female runners and 10 female non-runners were tested. Tendon cross-sectional area (CSA) and length of the patellar and Achilles tendon were determined with MRI. Ultrasonography-based measurement of tendon elongation and force during isometric contractions provided mechanical properties. Distal patellar and Achilles tendon CSAs were greater than the proximal part in all three groups (P<0.05). Weight-normalized Achilles tendon CSA were similar in trained (2.78+/-0.17 mm(2)/kg(3/4)) and untrained women (2.60+/-0.13 mm(2)/kg(3/4)), while that in trained men (3.77+/-0.27 mm(2)/kg(3/4)) was greater compared with trained women (P<0.01). Patellar tendon CSA were comparable in trained and untrained women, while that in trained men was greater compared with trained women (P<0.01). Patellar tendon stiffness was greater in male runners (3528+/-773 N/mm) compared with female runners (2069+/-666 N/mm) and non-runners (2477+/-381 N/mm), (P<0.01), but patellar tendon deformation, stress, strain and modulus were similar. These data indirectly suggest that the ability of Achilles and patellar tendons to adapt in response to habitual loading such as running is attenuated in women.
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Affiliation(s)
- E Westh
- Institute of Sports Medicine Copenhagen, Bispebjerg Hospital, Copenhagen, Denmark
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23
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Archambault JM, Jelinsky SA, Lake SP, Hill AA, Glaser DL, Soslowsky LJ. Rat supraspinatus tendon expresses cartilage markers with overuse. J Orthop Res 2007; 25:617-24. [PMID: 17318892 DOI: 10.1002/jor.20347] [Citation(s) in RCA: 105] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The goals of this study were to investigate the response of the rat supraspinatus tendon to overuse at the molecular level using transcriptional profiling, and to identify potential markers of tendinopathy. Adult rats were subjected to an overuse protocol that consists of downhill running (10% grade) at 17 m/min for 1 h/day, 5 days/week, for a total of either 1, 2, or 4 weeks. Another group of rats served as nonrunning time 0 controls. Transcriptional profiling was performed on the supraspinatus and patellar tendons using an Affymetrix rat genome array. A gene was considered to be differentially expressed if the p value from an ANOVA test was less than 0.01 and the difference between runners and controls was at least twofold at any time point. The supraspinatus tendon had increased expression of well-known cartilage genes such as col2a1, aggrecan, and sox9. These genes were not regulated in the patellar tendon, an internal comparator. Few genes associated with inflammation, or angiogenesis, were differentially expressed, and no significant change in the regulation of matrix metalloproteinases was detected. The results of this study suggest that by expressing more cartilage genes, the tendon is converting toward a fibrocartilage phenotype as a result of the repetitive loading and repeated compression of the tendon as it passes through the acromial arch.
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Affiliation(s)
- J M Archambault
- Wyeth Discovery Research, 200 Cambridge Park Drive, Cambridge, Massachusetts 02140, USA
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24
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Li KW, Lindsey DP, Wagner DR, Giori NJ, Schurman DJ, Goodman SB, Smith RL, Carter DR, Beaupre GS. Gene Regulation ex Vivo within a Wrap-Around Tendon. ACTA ACUST UNITED AC 2006; 12:2611-8. [PMID: 16995794 DOI: 10.1089/ten.2006.12.2611] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
This study tested the hypothesis that physiologic tendon loading modulates the fibrous connective tissue phenotype in undifferentiated skeletal cells. Type I collagen sponges containing human bone marrow stromal cells (MSCs) were implanted into the midsubstance of excised sheep patellar tendons. An ex vivo loading system was designed to cyclically stretch each tendon from 0 to 5% at 1.0 Hz. The MSC-sponge constructs were implanted into 2 tendon sites: the first site subjected to tension only and a second site located at an artificially created wrap-around region in which an additional compressive stress was generated transverse to the longitudinal axis of the tendon. The induced contact pressure at the wraparound site was 0.55 +/- 0.12 MPa, as quantified by pressure-sensitive film. An MSC-sponge construct was maintained free swelling in the same bath as an unloaded control. After 2 h of tendon stretching, the MSC-sponge constructs were harvested and real-time PCR was used to quantify Fos, Sox9, Cbfa1 (Runx2), and scleraxis mRNA expression as markers of skeletal differentiation. Two hours of mechanical loading distinctly altered MSC differentiation in the wrap-around region and the tensile-only region, as evidenced by differences in Fos and Sox9 mRNA expression. Expression of Fos mRNA was 13 and 52 times higher in the tensile-only and wrap-around regions, respectively, compared to the free-swelling controls. Expression of Sox9 mRNA was significantly higher (2.5-3 times) in MSCs from the wraparound region compared to those from the tensile-only region or in free-swelling controls. In contrast, expression levels for Cbfa1 did not differ among constructs. Scleraxis mRNA was not detected in any construct. This study demonstrates that the physiologic mechanical environment in the wrap-around regions of tendons provides stimuli for upregulating early response genes and transcription factors associated with chondrogenic differentiation. These differentiation responses begin within as little as 2 h after the onset of mechanical stimulation and may be the basis for the formation of fibrocartilage that is typically found in the wrap-around region of mature tendons in vivo.
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Affiliation(s)
- Kelvin W Li
- Bone & Joint Center of Excellence, VA Palo Alto Health Care System, Palo Alto, California 94304, USA
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25
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Morgan M, Kostyuk O, Brown RA, Mudera V. In SituMonitoring of Tendon Structural Changes by Elastic Scattering Spectroscopy: Correlation with Changes in Collagen Fibril Diameter and Crimp. ACTA ACUST UNITED AC 2006; 12:1821-31. [PMID: 16889512 DOI: 10.1089/ten.2006.12.1821] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The aim of this study was to monitor structural changes in loaded rabbit digital flexor tendons in situ and ex situ via elastic scattering spectroscopy (ESS). The optical setup consisted of a xenon white light source (lambda = 320-860 nm), connected to a fiber optic probe (with a source-detector separation of approximately 350 microm) and a spectrometer, controlled by a personal computer (PC). Cadaveric rabbit tendons were studied in situ under 3 tensional regimens: unloaded (no extrinsic tension applied), stretched, and 1-kg loaded and compared with excised tendons (i.e., no tension). Four times more light was detected in in situ unloaded tendons perpendicular to the tendon long axis than parallel to it. Backscatter anisotropy was expressed as the anisotropy factor (AF600nm: ratio of greatest to least backscatter intensity, measured with orthogonal probe positions). Differences in backscatter anisotropy between tendons from different digits were not significant. AF600nm had the smallest value (2.72 +/- 0.38) for the least aligned tendon preparations (excised tendons), and increased to 7.17 +/- 0.54 (1-kg loaded) as in situ loads were applied. Electron microscopy revealed that the distribution of collagen fibril diameters changed as loads were applied, with the diameter of larger fibrils decreasing approximately 33% for 1-kg loaded compared with excised tendons. Polarized light microscopy showed a characteristic crimp pattern in excised tendons, but this was hardly detectable in unloaded tendons and not detectable in tendons fixed in situ under a 1-kg load. We propose that the increase in optical anisotropy is a function of collagen fibril straightening and reducing fibril diameter as the tendon undergoes progressive loading. These findings are important for monitoring structure in vivo and in bioreactors for tissue engineers.
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Affiliation(s)
- Mary Morgan
- Tissue Repair and Engineering Centre, Institute of Orthopaedics and Musculoskeletal Science, University College London, Stanmore, United Kingdom
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26
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Shim JW, Elder SH. Influence of cyclic hydrostatic pressure on fibrocartilaginous metaplasia of achilles tendon fibroblasts. Biomech Model Mechanobiol 2006; 5:247-52. [PMID: 16416285 DOI: 10.1007/s10237-005-0013-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2005] [Accepted: 12/15/2005] [Indexed: 11/29/2022]
Abstract
The goal of this study was to demonstrate whether cyclically imposed hydrostatic pressure, compressive in nature, could induce fibrocartilaginous metaplasia in a purely tendinous cell source in vitro. The effect of short-duration cyclic hydrostatic pressure on tendon fibroblasts (tenocytes) expanded from rat Achilles tendon was studied. Total RNA was isolated either immediately after loading or 24 h later. The mRNA expression of tendon and cartilage specific markers - Collagen types I and II, Sox9, and Aggrecan was quantified by real-time reverse transcription polymerase chain reaction over multiple biological samples (n=6). For immediately isolated RNA samples, there were statistically significant increases in mRNA expression of Aggrecan and Collagen type II, while Collagen type I significantly decreased. Noticeably, for RNA samples isolated 24 h later, there were further increases in mRNA expression of Aggrecan and Collagen type II, whereas Collagen type I increased roughly three-fold relative to the non-loaded control. These findings support the hypothesis that cyclic hydrostatic pressurization can induce fibrocartilaginous metaplasia in tenocytes by upregulation of cartilaginous gene expression. Also, it was demonstrated that changes in mRNA expression as a result of single 2 h pressurization persist even up to 24 h.
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Affiliation(s)
- J W Shim
- Ag & Biological Engineering Biomedical Engineering Program, Agricultural & Biological Engineering Department, Mississippi State University, Starkville, Box 9672, MS 39762, USA
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Nakama LH, King KB, Abrahamsson S, Rempel DM. Evidence of tendon microtears due to cyclical loading in an in vivo tendinopathy model. J Orthop Res 2005; 23:1199-205. [PMID: 16140201 DOI: 10.1016/j.orthres.2005.03.006] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Revised: 03/11/2005] [Indexed: 02/04/2023]
Abstract
Tendon injuries at the epicondyle can occur in athletes and workers whose job functions involve repetitive, high force hand activities, but the early pathophysiologic changes of tendon are not well known. The purpose of this study was to evaluate early tendon structural changes, specifically the formation of microtears, caused by cyclical loading. The Flexor Digitorum Profundus (FDP) muscle of nine New Zealand White rabbits was stimulated to contract repetitively for 80 h of cumulative loading over 14 weeks. The contralateral limb served as a control. The tendon at the medial epicondyle insertion site was harvested, sectioned, and stained. Microtears were quantified, using image analysis software, in four regions of the tendon, two regions along the enthesis and two distal to the enthesis. The tear density (loaded: 1329+/-546 tears/mm(2); unloaded: 932+/-474 tears/mm(2)) and mean tear size (loaded: 18.3+/-6.1 microm(2); unloaded: 14.0+/-4.8 microm(2)) were significantly greater in the loaded limb (p<0.0001) across all regions compared to the unloaded contralateral limb. These early microstructural changes in a repetitively loaded tendon may initiate a degenerative process that leads to tendinosis.
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Affiliation(s)
- Leena H Nakama
- Joint Graduate Group in Bioengineering, University of California, Berkeley, CA, USA
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Butler DL, Shearn JT, Juncosa N, Dressler MR, Hunter SA. Functional tissue engineering parameters toward designing repair and replacement strategies. Clin Orthop Relat Res 2004:S190-9. [PMID: 15480066 DOI: 10.1097/01.blo.0000144858.65450.d2] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Abnormal joint kinematics and loads induced after soft tissue injuries are assumed to contribute to long-term degenerative joint disease and osteoarthritis. Controlling abnormal kinematics after repair and reconstruction of these injured structures would seem to be important for limiting wear of the articular cartilage surfaces. In this paper, we propose to expand the paradigm of functional tissue engineering to more fully characterize normal joint function and to establish design parameters for soft tissue repair and reconstruction to ultimately protect joint surfaces after surgery. Structure-function relationships are examined for tissues of increasing complexity, from tendons to menisci. Emphasis is placed on understanding normal in vivo function of tissues by conducting biomechanical experiments in vitro that better mimic in vivo conditions. This process yields nine classes of functional tissue engineering parameters: differential fiber length, in vivo force and displacement, variations in relative attachment site locations, loading from adjacent structures, fiber interactions, types of insertion, regional variations in material properties, nonparallel fiber orientations, and complex loading within the structure. These functional tissue engineering parameters are useful not only for understanding the function of normal tissues but for more effectively designing their repair and replacement. This paper concludes with a discussion of research directions that investigators might take to establish tissue-specific functional tissue engineering parameters for improving joint function and reducing articular surface degradation and osteoarthritis.
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Affiliation(s)
- David L Butler
- Department of Biomedical Engineering, University of Cincinnati, Cincinnati, OH 45221, USA.
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Screen HRC, Lee DA, Bader DL, Shelton JC. An investigation into the effects of the hierarchical structure of tendon fascicles on micromechanical properties. Proc Inst Mech Eng H 2004; 218:109-19. [PMID: 15116898 DOI: 10.1243/095441104322984004] [Citation(s) in RCA: 149] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
During physiological loading, a tendon is subjected to tensile strains in the region of up to 6 per cent. These strains are reportedly transmitted to cells, potentially initiating specific mechanotransduction pathways. The present study examines the local strain fields within tendon fascicles subjected to tensile strain in order to determine the mechanisms responsible for fascicle extension. A hierarchical approach to the analysis was adopted, involving micro and macro examination. Micro examination was carried out using a custom-designed rig, to enable the analysis of local tissue strains in isolated fascicles, using the cell nuclei as strain markers. In macro examination, a video camera was used to record images of the fascicles during mechanical testing, highlighting the point of crimp straightening and macro failure. Results revealed that local tensile strains within a collagen fibre were consistently smaller than the applied strain and showed no further increase once fibres were aligned. By contrast, between-group displacements, a measure of fibre sliding, continued to increase beyond crimp straightening, reaching a mean value of 3.9 per cent of the applied displacement at 8 per cent strain. Macro analysis displayed crimp straightening at a mean load of 1 N and sample failure occurred through the slow unravelling of the collagen fibres. Fibre sliding appears to provide the major mechanism enabling tendon fascicle extension within the rat-tail tendon. This process will necessarily affect local and cellular strains and consequently mechanotransduction pathways.
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Affiliation(s)
- H R C Screen
- Medical Engineering Division, Department of Engineering, Queen Mary, University of London, UK
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30
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Hildebrand KA, Frank CB, Hart DA. Gene intervention in ligament and tendon: current status, challenges, future directions. Gene Ther 2004; 11:368-78. [PMID: 14724683 DOI: 10.1038/sj.gt.3302198] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Ligament and tendon injuries are common clinical problems. Healing of these tissues occurs, but their properties do not return to normal. This predisposes to recurrent injuries, instability and arthritis, loss of motion and weakness. Gene therapy offers a novel approach to the repair of ligaments and tendons. Introduction of genes into ligaments and tendons using vectors has been successful. Marker genes and therapeutic genes have been introduced into both tissues with evidence of corresponding functional alterations. In addition, gene transfer has been used to manipulate the healing environment, opening the possibility of gene transfer to investigate ligament and tendon development and homeostasis, in addition to using this technology therapeutically. Several factors modulate the 'success' of gene transfer in these tissues.
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Affiliation(s)
- K A Hildebrand
- McCaig Centre for Joint Injury and Arthritis Research, University of Calgary, Calgary, AB, Canada
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31
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Abstract
Fibrocartilage is an avascular tissue that is best documented in menisci, intervertebral discs, tendons, ligaments, and the temporomandibular joint. Several of these sites are of particular interest to those in the emerging field of tissue engineering. Fibrocartilage cells frequently resemble chondrocytes in having prominent rough endoplasmic reticulum, many glycogen granules, and lipid droplets, and intermediate filaments together with and actin stress fibers that help to determine cell organization in the intervertebral disc. Fibrocartilage cells can synthesize a variety of matrix molecules including collagens, proteoglycans, and noncollagenous proteins. All the fibrillar collagens (types I, II, III, V, and XI) have been reported, together with FACIT (types IX and XII) and network-forming collagens (types VI and X). The proteoglycans include large, aggregating types (aggrecan and versican) and small, leucine-rich types (decorin, biglycan, lumican, and fibromodulin). Less attention has been paid to noncollagenous proteins, although tenascin-C expression may be modulated by mechanical strain. As in hyaline cartilage, matrix metalloproteinases are important in matrix turnover and fibrocartilage cells are capable of apoptosis.
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Affiliation(s)
- M Benjamin
- School of Biosciences, Cardiff University, Cardiff CF10 3US, United Kingdom
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32
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Magnusson SP, Kjaer M. Region-specific differences in Achilles tendon cross-sectional area in runners and non-runners. Eur J Appl Physiol 2003; 90:549-53. [PMID: 12905044 DOI: 10.1007/s00421-003-0865-8] [Citation(s) in RCA: 120] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/07/2003] [Indexed: 10/26/2022]
Abstract
The present study examined the cross-sectional area (CSA) of the Achilles tendon in subjects who repeatedly exposed their tendons to large loads (habitual runners) compared to control subjects (non-runners). Six male habitual runners [36 (7) years, 70.9 (4.4) kg and 1.84 (0.05) m, +/-SD] who had performed distance running (approximately 80 km per week) for the last 5 years were compared to six non-runners [34 (3) years, 81.2 (8.7) kg and 1.81 (0.02) m, +/-SD]. Tendon CSA was obtained from MR images obtained with the ankle in a neutral position (90 degrees ). The most proximal aspect of the tuberosity of calcaneus was used as a landmark to standardize the levels of images: the most distal image (1) was obtained 10 mm above the proximal tuberosity of calcaneus, and the most proximal image (7) was obtained 70 mm above the proximal tuberosity of calcaneus. There was a significant difference in CSA along the length of the tendon both in runners ( P<0.001) and non-runners ( P<0.01). In non-runners and runners the CSA of the most distal part was 51% and 85% greater than the most proximal part of the tendon, respectively. Furthermore, there was a difference in tendon CSA between the groups, such that runners had a greater CSA (36%) than non-runners at the most distal part of the tendon ( P<0.05). The greater CSA in the distal tendon may reflect differences in structural properties along the length of the human Achilles tendon, while the greater CSA in runners compared to non-runners may indicate a region-specific hypertrophy in response to the habitual loading of running.
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Affiliation(s)
- S Peter Magnusson
- Sports Medicine Research Unit, Bispebjerg Hospital, Bispebjerg bakke 23, 2400 NV, Copenhagen, Denmark.
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33
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Abstract
The linear organization of collagen fibers in tendons results in optimal stiffness and strength at low strains under tensile load. However, this organization makes repairing ruptured or lacerated tendons extremely difficult. Current suturing techniques to join split ends of tendons, while providing sufficient mechanical strength to prevent gapping, are inadequate to carry normal loads. Immobilization protocols necessary to restore tendon congruity result in scar formation at the repair site and peripheral adhesions that limit excursion. These problems are reviewed to emphasize the need for novel approaches to tendon repair, one of which is the development of biomimetic tendons. The objective of the empirical work described here was to produce biologically-based, biocompatible tendon replacements with appropriate mechanical properties to enable immediate mobilization following surgical repair. Nor-dihydroguaiaretic acid (NDGA), a di-catechol from creosote bush, caused a dose dependent increase in the material properties of reconstituted collagen fibers, achieving a 100-fold increase in strength and stiffness over untreated fibers. The maximum tensile strength of the optimized NDGA treated fibers averaged 90 MPa; the elastic modulus of these fibers averaged 580 MPa. These properties were independent of strain rates ranging from 0.60 to 600 mm/min. Fatigue tests established that neither strength nor stiffness were affected after 80 k cycles at 5% strain. Treated fibers were not cytotoxic to tendon fibroblasts. Fibroblasts attached and proliferated on NDGA treated collagen normally. NDGA-fibers did not elicit a foreign body response nor did they stimulate an immune reaction during six weeks in vivo. The fibers survived 6 weeks with little evidence of fragmentation or degradation. The polymerization scheme described here produces a fiber-reinforced NDGA-polymer with mechanical properties approaching an elastic solid. The strength, stiffness and fatigue properties of the NDGA-treated fibers are comparable to those of tendon. These fibers are biocompatible with tendon fibroblasts and elicit little rejection or antigenic response in vivo. These results indicate that NDGA polymerization may provide a viable approach for producing collagenous materials that can be used to bridge gaps in ruptured or lacerated tendons. The tendon-like properties of the NDGA-fiber would allow early mobilization after surgical repair. We predict that timely loading of parted tendons joined by this novel biomaterial will enhance mechanically driven production of neo-tendon by the colonizing fibroblasts and result in superior repair and rapid return to normal properties.
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Affiliation(s)
- Thomas J Koob
- Skeletal Biology Section, Center for Research in Skeletal Development and Pediatric Orthopaedics, Shriners Hospital for Children, 12502 North Pine Drive, Tampa, FL 33612, USA.
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Ameye L, Aria D, Jepsen K, Oldberg A, Xu T, Young MF. Abnormal collagen fibrils in tendons of biglycan/fibromodulin-deficient mice lead to gait impairment, ectopic ossification, and osteoarthritis. FASEB J 2002; 16:673-80. [PMID: 11978731 DOI: 10.1096/fj.01-0848com] [Citation(s) in RCA: 268] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Small leucine-rich proteoglycans (SLRPs) regulate extracellular matrix organization, a process essential in development, tissue repair, and metastasis. In vivo interactions of biglycan and fibromodulin, two SLRPs highly expressed in tendons and bones, were investigated by generating biglycan/fibromodulin double-deficient mice. Here we show that collagen fibrils in tendons from mice deficient in biglycan and/or fibromodulin are structurally and mechanically altered resulting in unstable joints. As a result, the mice develop successively and progressively 1) gait impairment, 2) ectopic tendon ossification, and 3) severe premature osteoarthritis. Forced use of the joints increases ectopic ossification and osteoarthritis in the double-deficient mice, further indicating that structurally weak tendons cause the phenotype. The study shows that mutations in SLRPs may predispose to osteoarthritis and offers a valuable and unique animal model for spontaneous osteoarthritis characterized by early onset and a rapid progression of the disease.
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Affiliation(s)
- Laurent Ameye
- Craniofacial and Skeletal Diseases Branch, NIDCR, National Institutes of Health, Bethesda, Maryland, USA.
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Abstract
In this study, an ex vivo organ culture system that allows the application of controlled loads to the anterior cruciate ligament (ACL) was designed and used to characterize the influence of a step input in mechanical load on gene expression. A procedure for isolating bone-ACL-bone (B-ACL-B) complexes from rat knees was developed. After harvest and 24 hour culture, B-ACL-B complexes exhibited percentages of viability similar to that in intact ACLs (approximately 90%). Application of a physiologically relevant load of 5 N (superimposed on a I N tare load) resulted in changes in levels of mRNA encoding type I collagen. While levels of type I collagen mRNA significantly increased 32+/-13% (mean +/- standard errors of the mean (SEM)) over controls within the first hour of loading, levels decreased significantly to 44+/-9% of control after 2 h. Displacements induced by the 5 N load were measured by video dimensional analysis. Calculated axial strains of 0.141+/-0.034 were achieved rapidly during the first hour and remained essentially unchanged thereafter. These results demonstrate the feasibility of maintaining ligaments in organ culture and illustrate the time course expression of type I collagen following the application of a mechanical load.
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Affiliation(s)
- Adam H Hsieh
- Department of Bioengineering, University of California, San Diego, La Jolla 92093, USA
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36
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Benjamin M, McGonagle D. The anatomical basis for disease localisation in seronegative spondyloarthropathy at entheses and related sites. J Anat 2001; 199:503-26. [PMID: 11760883 PMCID: PMC1468363 DOI: 10.1046/j.1469-7580.2001.19950503.x] [Citation(s) in RCA: 321] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The 2 major categories of idiopathic inflammatory arthritis are rheumatoid arthritis and the seronegative spondyloarthropathies. Whilst the synovium is the primary site of joint disease in the former, the primary site in the latter is less well defined. However, it has recently been proposed that enthesitis-associated changes in the spondyloarthropathies are primary and that all other joint manifestations are secondary. Nevertheless, some of the sites of disease localisation have not been adequately explained in terms of enthesitis. This article summarises current knowledge of the structure, function, blood supply, innervation, molecular composition and histopathology of the classic enthesis (i.e. the bony attachment of a tendon or ligament) and introduces the concept of 'functional' and articular 'fibrocartilaginous' entheses. The former are regions where tendons or ligaments wrap-around bony pulleys, but are not attached to them, and the latter are synovial joints that are lined by fibrocartilage rather than hyaline cartilage. We describe how these 3 types of entheses relate to other, and how all are prone to pathological changes in spondyloarthropathy. We propose that the inflammatory responses characteristic of spondyloarthropathies are triggered at these seemingly diverse sites, in genetically susceptible individuals, by a combination of anatomical factors which lead to higher levels of tissue microtrauma, and the deposition of microbes.
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Affiliation(s)
- M Benjamin
- Anatomy Unit, School of Biosciences, Cardiff University, UK.
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37
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Milz S, Valassis G, Büttner A, Maier M, Putz R, Ralphs JR, Benjamin M. Fibrocartilage in the transverse ligament of the human acetabulum. J Anat 2001; 198:223-8. [PMID: 11273046 PMCID: PMC1468208 DOI: 10.1046/j.1469-7580.2001.19820223.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Biomechanical experiments on isolated hip joints have suggested that the transverse ligament acts as a bridle for the lunate articular surface of the acetabulum during load bearing, but there are inherent limitations in such studies because the specimens are fixed artificially to testing devices and there are no modifying influences of muscle pull. Further evidence is thus needed to substantiate the theory. Here we argue that if the horns of the lunate surface are forced apart under load, the ligament would straighten and become compressed against the femoral head. It would thus be expected to share some of the features of tendons and ligaments that wrap around bony pulleys and yet previous work has suggested that the transverse ligament is purely fibrous. Transverse ligaments were removed from 8 cadavers (aged 17-39 y) and fixed in 90% methanol. Cryosections were immunolabelled with antibodies against collagens (types I, II, III, VI), glycosaminoglycans (chondroitins 4 and 6 sulphate, dermatan sulphate, keratan sulphate) and proteoglycans (aggrecan, link protein, versican, tenascin). A small sesamoid fibrocartilage was consistently present in the centre of each transverse ligament, near its inner surface at the site where it faced the femoral head. Additionally, a more prominent enthesis fibrocartilage was found at both bony attachments. All fibrocartilage regions, in at least some specimens, labelled for type II collagen, chondroitin 6 sulphate, aggrecan and link protein, molecules more typically associated with articular cartilage. The results suggest that the ligament should be classed as containing a 'moderately cartilaginous' sesamoid fibrocartilage, adapted to withstanding compression. This supports the inferences that can be drawn from previous biomechanical studies. We cannot give any quantitative estimate of the levels of compression experienced. All that can be said is that the ligament occupies an intermediate position in the spectrum of fibrocartilaginous tissues. It is more cartilaginous than some wrap-around tendons at the wrist, but less cartilaginous than certain other wrap-around ligaments, e.g. the transverse ligament of the atlas.
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Affiliation(s)
- S Milz
- Anatomische Anstalt, Ludwig-Maximilians-Universität, München, Germany.
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