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Camy C, Grünewald T, Lamy E, Roseren F, Caumes M, Fovet T, Brioche T, Genovesio C, Chopard A, Pithioux M, Roffino S. Characterization of the mechanical properties of the mouse Achilles tendon enthesis by microindentation. Effects of unloading and subsequent reloading. Bone Rep 2024; 20:101734. [PMID: 38292933 PMCID: PMC10825371 DOI: 10.1016/j.bonr.2024.101734] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 12/14/2023] [Accepted: 01/03/2024] [Indexed: 02/01/2024] Open
Abstract
The fibrocartilaginous tendon enthesis, i.e. the site where a tendon is attached to bone through a fibrocartilaginous tissue, is considered as a functionally graded interface. However, at local scale, a very limited number of studies have characterized micromechanical properties of this transitional tissue. The first goal of this work was to characterize the micromechanical properties of the mineralized part of the healthy Achilles tendon enthesis (ATE) through microindentation testing and to assess the degree of mineralization and of carbonation of mineral crystals by Raman spectroscopy. Since little is known about enthesis biological plasticity, our second objective was to examine the effects of unloading and reloading, using a mouse hindlimb-unloading model, on both the micromechanical properties and the mineral phase of the ATE. Elastic modulus, hardness, degree of mineralization, and degree of carbonation were assessed after 14 days of hindlimb suspension and again after a subsequent 6 days of reloading. The elastic modulus gradually increased along the mineralized part of the ATE from the tidemark to the subchondral bone, with the same trend being found for hardness. Whereas the degree of carbonation did not differ according to zone of measurement, the degree of mineralization increased by >70 % from tidemark to subchondral bone. Thus, the gradient in micromechanical properties is in part explained by a mineralization gradient. A 14-day unloading period did not appear to affect the gradient of micromechanical properties of the ATE, nor the degree of mineralization or carbonation. However, contrary to a short period of unloading, early return to normal mechanical load reduced the micromechanical properties gradient, regardless of carbonate-to-phosphate ratios, likely due to the more homogeneous degree of mineralization. These findings provide valuable data not only for tissue bioengineering, but also for musculoskeletal clinical studies and microgravity studies focusing on long-term space travel by astronauts.
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Affiliation(s)
- Claire Camy
- Aix Marseille Univ, CNRS, ISM, 13009 Marseille, France
| | - Tilman Grünewald
- Aix Marseille Univ, CNRS, Centrale Marseille, Institut Fresnel, Marseille, France
| | - Edouard Lamy
- Aix Marseille Univ, CNRS, ISM, 13009 Marseille, France
| | - Flavy Roseren
- Aix Marseille Univ, CNRS, ISM, 13009 Marseille, France
- Aix Marseille Univ, APHM, CNRS, ISM, Mecabio Platform, Department of Orthopaedics and Traumatology, 13009 Marseille, France
| | | | - Théo Fovet
- DMEM, Montpellier University, INRAE, UMR 866, Montpellier, France
| | - Thomas Brioche
- DMEM, Montpellier University, INRAE, UMR 866, Montpellier, France
| | | | - Angèle Chopard
- DMEM, Montpellier University, INRAE, UMR 866, Montpellier, France
| | - Martine Pithioux
- Aix Marseille Univ, CNRS, ISM, 13009 Marseille, France
- Aix Marseille Univ, APHM, CNRS, ISM, Mecabio Platform, Department of Orthopaedics and Traumatology, 13009 Marseille, France
- Aix Marseille Univ, APHM, CNRS, ISM, Sainte-Marguerite Hospital, Institute for Locomotion, Department of Orthopaedics and Traumatology, 13009 Marseille, France
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Kastoft R, Barfod K, Bencke J, Speedtsberg MB, Hansen SB, Penny JØ. 1.7 cm elongated Achilles tendon did not alter walking gait kinematics 4.5 years after non-surgical treatment. Knee Surg Sports Traumatol Arthrosc 2022; 30:3579-3587. [PMID: 35234975 DOI: 10.1007/s00167-022-06874-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Accepted: 01/12/2022] [Indexed: 12/19/2022]
Abstract
PURPOSE The aim of the present study was to evaluate Achilles tendon length after non-surgical treatment of acute Achilles tendon rupture (aATR), and to evaluate indirect effects of possible persistent elongation on kinematics. METHODS The study was performed as a cross-sectional study based on a population of patients from an RCT regarding non-operative treatment of aATR. Thirty-seven patients out of the 56 in the original RCT participated with at a follow up of 4-5 years after aATR. Primary outcome was Achilles tendon elongation. Additional outcomes were Achilles tendon resting angle (ATRA), calf circumference, passive ankle plantar and dorsiflexion and loading pattern. Foot pressure mapping was performed to measure plantar loading distribution pattern; medial and lateral forefoot peak pressure, heel peak pressure, medial versus lateral loading pattern and timing of heel lift during roll over process. The healthy leg was used as a control. RESULTS The injured Achilles tendon was significantly elongated by 1.7 (SD 1.6) cm compared to the non-injured leg. A slight delay of 2.6% (SD 6.0) was measured in heel lift in the injured side compared to the non-injured leg. We found no significant difference in forefoot peak pressure, medial and lateral peak pressure as well as heel peak pressure, and no correlation was found between Achilles tendon length and pressure measurements. Finally, dorsiflexion was 1.9°(SD1.28) larger, ATRA 8.1°(SD6.7) larger, and calf circumference 1.6 cm (SD1.1) lower on the injured leg. CONCLUSION The Achilles tendon was 1.7 cm elongated 4.5 years after the initial injury and significant changes in ATRA, calf circumference and passive dorsiflexion was present. Except for a slight delay in heel lift-off, kinematics during walking was symmetrical between injured and healthy leg, even with an elongated tendon on the injured leg. The clinical relevance of the Achilles tendon elongation is uncertain. LEVEL OF EVIDENCE II. CLINICAL TRIALS IDENTIFIER NCT02760784.
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Affiliation(s)
- Rasmus Kastoft
- Department of Orthopedic Surgery, Copenhagen University Hospital, Hvidovre, Denmark.
| | - Kristoffer Barfod
- Department of Orthopedic Surgery, Copenhagen University Hospital, Hvidovre, Denmark
| | - Jesper Bencke
- Laboratory of Human Movement Analysis, Department of Orthopedic Surgery, Copenhagen University Hospital, Amager, Hvidovre, Denmark
| | - Merete B Speedtsberg
- Laboratory of Human Movement Analysis, Department of Orthopedic Surgery, Copenhagen University Hospital, Amager, Hvidovre, Denmark
| | - Sanja Bay Hansen
- Department of Radiology, Center for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital, Hvidovre, Denmark
| | - Jeannette Ø Penny
- Department of Orthopedic Surgery, Copenhagen University Hospital, Hvidovre, Denmark
- Department of Orthopaedic Surgery, Zealand University Hospital, Koege, Denmark
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3
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Camy C, Brioche T, Senni K, Bertaud A, Genovesio C, Lamy E, Fovet T, Chopard A, Pithioux M, Roffino S. Effects of hindlimb unloading and subsequent reloading on the structure and mechanical properties of Achilles tendon-to-bone attachment. FASEB J 2022; 36:e22548. [PMID: 36121701 DOI: 10.1096/fj.202200713r] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Revised: 08/10/2022] [Accepted: 09/02/2022] [Indexed: 11/11/2022]
Abstract
While muscle and bone adaptations to deconditioning have been widely described, few studies have focused on the tendon enthesis. Our study examined the effects of mechanical loading on the structure and mechanical properties of the Achilles tendon enthesis. We assessed the fibrocartilage surface area, the organization of collagen, the expression of collagen II, the presence of osteoclasts, and the tensile properties of the mouse enthesis both after 14 days of hindlimb suspension (HU) and after a subsequent 6 days of reloading. Although soleus atrophy was severe after HU, calcified fibrocartilage (CFc) was a little affected. In contrast, we observed a decrease in non-calcified fibrocartilage (UFc) surface area, collagen fiber disorganization, modification of morphological characteristics of the fibrocartilage cells, and altered collagen II distribution. Compared to the control group, restoring normal loads increased both UFc surface area and expression of collagen II, and led to a crimp pattern in collagen. Reloading induced an increase in CFc surface area, probably due to the mineralization front advancing toward the tendon. Functionally, unloading resulted in decreased enthesis stiffness and a shift in site of failure from the osteochondral interface to the bone, whereas 6 days of reloading restored the original elastic properties and site of failure. In the context of spaceflight, our results suggest that care must be taken when performing countermeasure exercises both during missions and during the return to Earth.
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Affiliation(s)
- Claire Camy
- Aix Marseille University, CNRS, ISM, Institute of Movement Sciences, Marseille, France
| | - Thomas Brioche
- DMEM, Montpellier University, INRAE, UMR 866, Montpellier, France
| | - Karim Senni
- Laboratoire EBInnov, Ecole de Biologie Industrielle-EBI, Cergy, France
| | - Alexandrine Bertaud
- Aix Marseille Univ, INSERM, INRAE, C2VN, Marseille, France.,Laboratoire de Biochimie, Faculté de Pharmacie, Marseille, France
| | - Cécile Genovesio
- Laboratoire de Biochimie, Faculté de Pharmacie, Marseille, France
| | - Edouard Lamy
- Aix Marseille University, CNRS, ISM, Institute of Movement Sciences, Marseille, France.,Laboratoire de Biochimie, Faculté de Pharmacie, Marseille, France
| | - Théo Fovet
- DMEM, Montpellier University, INRAE, UMR 866, Montpellier, France
| | - Angèle Chopard
- DMEM, Montpellier University, INRAE, UMR 866, Montpellier, France
| | - Martine Pithioux
- Aix Marseille University, CNRS, ISM, Institute of Movement Sciences, Marseille, France.,Department of Orthopaedics and Traumatology, Aix Marseille Univ, APHM, CNRS, ISM, Sainte-Marguerite Hospital, Institute for Locomotion, Marseille, France.,Aix Marseille Univ, APHM, CNRS, Centrale Marseille, ISM, Mecabio Platform, Anatomy Laboratory, Timone, Marseille, France
| | - Sandrine Roffino
- Aix Marseille University, CNRS, ISM, Institute of Movement Sciences, Marseille, France.,Aix Marseille Univ, APHM, CNRS, Centrale Marseille, ISM, Mecabio Platform, Anatomy Laboratory, Timone, Marseille, France
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Wang C, Fan H, Li Y, Yun Z, Zhang Z, Zhu Q. Effectiveness of platelet-rich plasma injections for the treatment of acute Achilles tendon rupture: A systematic review and meta-analysis. Medicine (Baltimore) 2021; 100:e27526. [PMID: 34731144 PMCID: PMC8519239 DOI: 10.1097/md.0000000000027526] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Accepted: 09/29/2021] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND The effect of platelet-rich plasma (PRP) on patients with acute Achilles tendon rupture is still controversial. The purpose of this systematic review is to assess the efficacy of PRP injections treating acute Achilles tendon rupture. METHODS A comprehensive electronic literature search was performed in the PubMed, Embase, Cochrane Library, and Web of Science databases to identify relevant studies that were published prior to April 29, 2021. Randomized controlled trials evaluating the efficacy of PRP injections in treating patients with acute Achilles tendon rupture were included. Statistical analyses were conducted using RevMan software. RESULTS Five randomized controlled trials were included in this systematic review. The results of the meta-analysis showed that PRP has positive effects on ankle dorsiflexion angle, dorsal extension strength of the ankle, and calf circumference compared with that in controls. However, the current evidence failed to show that PRP effectively improves ankle plantar flexion angle, plantar flexion strength of the ankle, and pain. CONCLUSIONS PRP injections for the treatment of acute Achilles tendon rupture significantly improved ankle dorsiflexion angle, dorsal extension strength of the ankle, and calf circumference compared with that in controls. Additional studies with larger sample sizes, more rigorous designs and standardized protocols are needed to draw more reliable and accurate conclusions.
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Affiliation(s)
- Chenglong Wang
- Department of Orthopedics, China-Japan Union Hospital of Jilin University, Changchun, China
| | - Hua Fan
- Department of Vascular Surgery, Affiliated Hospital of Qingdao University, Qingdao, China
| | - Yuhuan Li
- Department of Orthopedics, China-Japan Union Hospital of Jilin University, Changchun, China
| | - Zhihe Yun
- Department of Orthopedics, The Second Hospital of Jilin University, Changchun, China
| | - Zhuo Zhang
- Department of Orthopedics, China-Japan Union Hospital of Jilin University, Changchun, China
| | - Qingsan Zhu
- Department of Orthopedics, China-Japan Union Hospital of Jilin University, Changchun, China
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Zhang YJ, Long X, Du JY, Wang Q, Lin XJ. Is Early Controlled Motion and Weightbearing Recommended for Nonoperatively Treated Acute Achilles Tendon Rupture? A Systematic Review and Meta-analysis. Orthop J Sports Med 2021; 9:23259671211024605. [PMID: 34568502 PMCID: PMC8461133 DOI: 10.1177/23259671211024605] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 02/28/2021] [Indexed: 12/28/2022] Open
Abstract
Background There is disagreement as to whether early controlled motion and weightbearing confer a beneficial effect for nonoperatively treated acute Achilles tendon rupture (ATR) compared with immobilization and late weightbearing. Purpose To conduct a meta-analysis of randomized controlled trials (RCTs) to determine whether early controlled motion and weightbearing results in different outcomes compared with immobilization and late weightbearing for nonoperatively treated patients with acute ATR. Study Design Systematic review; Level of evidence, 1. Methods We conducted a search in the PubMed, Web of Science, and EMBASE databases for relevant RCTs in humans from January 1981 to August 2020. The primary outcome was the Achilles Tendon Total Rupture Score (ATRS) at 1-year follow-up. The secondary outcomes were the rerupture rate, return to sports activity and work, and the heel-rise work (limb symmetry index [LSI]). Study quality was assessed using the Cochrane Collaboration risk of bias tool. Results Included were 7 RCTs involving 424 participants (n = 215 treated with early controlled motion and weightbearing [early group], n = 209 treated with immobilization and late weightbearing [late group]). The quality assessment indicated a low risk of bias in all included RCTs. There was no difference between the early and late groups regarding the ATRS (mean difference [MD], -0.220; 95% CI, -4.489 to 4.049; P = .920). Likewise, we found no difference between the 2 groups in terms of the rerupture rate (odds ratio [OR], 1.107; 95% CI, 0.552 to 2.219; P = .775), the number of patients who returned to sports (OR, 0.766; 95% CI, 0.438 to 1.341; P = .351) and returned to work (OR, 0.706; 95% CI, 0.397 to 1.253; P = .234), the time to return to work (MD, -2.802 days; 95% CI, -6.525 to 0.921 days; P = .140), or the heel-rise work LSI (MD, -0.135; 95% CI, -6.243 to 5.973; P = .965). Conclusion No significant differences were found between early controlled motion and weightbearing compared with immobilization and late weightbearing regarding the ATRS, the rerupture rate, return to sports activity and work, and the heel-rise work in nonoperatively treated patients with acute ATR.
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Affiliation(s)
- Yi-Jun Zhang
- Department of Orthopedics, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, PR China
| | - Xiao Long
- Department of Orthopedics, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, PR China
| | - Jing-Yu Du
- Department of Orthopedics, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, PR China
| | - Quan Wang
- Department of Orthopedics, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, PR China
| | - Xiang-Jin Lin
- Department of Orthopedics, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, PR China
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6
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Corbu A, Cosma DI, Vasilescu DE, Vasilescu D, Cristea S. Sonoelastographic Findings in Clubfeet. Int J Gen Med 2021; 14:2763-2775. [PMID: 34188530 PMCID: PMC8236278 DOI: 10.2147/ijgm.s320115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Accepted: 06/11/2021] [Indexed: 11/23/2022] Open
Abstract
Purpose One of the main features of congenital idiopathic clubfoot is the increased stiffness of soft tissues. With the growing popularity and availability of sonoelastography as a method to assess the stiffness of different tissues, we considered applying it to congenital clubfeet in order to to determine whether sonoelastography can be a useful imaging method for the evaluation of clubfeet, to assess whether there are any differences in stiffness of specific tendons between clubfeet and normal contralateral feet and to observe which treatment methods have an impact on the aspect of these structures on the elastograms. Patients and Methods A case-control study was performed involving 10 adolescent patients with unilateral idiopathic congenital clubfeet who were treated either with the Ponseti method or surgically with posteromedial release (PMR) during early infancy. Using compression sonoelastography, we obtained semi-quantitative data expressed as fat to tendon ratios in treated clubfeet and normal contralateral feet. The tendons of the following muscles were examined: tibialis anterior, tibialis posterior, flexor hallucis longus, peroneus longus and Achilles tendon at three levels (calcaneal insertion, lengthened zone and musculotendinous junction). Results The only statistically significant difference in the strain ratio (p = 0.023) between clubfeet and normal feet was at the level of the calcaneal insertion of the Achilles tendon, which was stiffer in clubfeet. Although other differences were not statistically significant, they may reflect some of the pathological modifications of clubfeet. Conclusion Overall, sonoelastography may be a useful examination tool in the quantitative and qualitative assessment of soft tissue stiffness in clubfeet, but further research is necessary.
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Affiliation(s)
- Andrei Corbu
- University of Medicine and Pharmacy Carol Davila Bucharest, Romania, Department of Orthopaedics and Traumatology, Bucharest, Romania
| | - Dan Ionut Cosma
- Clinical Rehabilitation Hospital Cluj-Napoca, Department of Orthopaedics and Traumatology, Cluj-Napoca, Cluj, Romania
| | - Dana Elena Vasilescu
- University of Medicine and Pharmacy Iuliu Hatieganu, Cluj-Napoca, Romania; Department of Orthopaedics-Traumatology and Paediatric Orthopaedics, Cluj-Napoca, Cluj, Romania
| | - Dan Vasilescu
- Clinical Emergency Hospital Cluj-Napoca, Department of Radiology and Imaging, Cluj-Napoca, Cluj, Romania
| | - Stefan Cristea
- University of Medicine and Pharmacy Carol Davila Bucharest, Romania, Department of Orthopaedics and Traumatology, Bucharest, Romania
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Siadat SM, Zamboulis DE, Thorpe CT, Ruberti JW, Connizzo BK. Tendon Extracellular Matrix Assembly, Maintenance and Dysregulation Throughout Life. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1348:45-103. [PMID: 34807415 DOI: 10.1007/978-3-030-80614-9_3] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
In his Lissner Award medal lecture in 2000, Stephen Cowin asked the question: "How is a tissue built?" It is not a new question, but it remains as relevant today as it did when it was asked 20 years ago. In fact, research on the organization and development of tissue structure has been a primary focus of tendon and ligament research for over two centuries. The tendon extracellular matrix (ECM) is critical to overall tissue function; it gives the tissue its unique mechanical properties, exhibiting complex non-linear responses, viscoelasticity and flow mechanisms, excellent energy storage and fatigue resistance. This matrix also creates a unique microenvironment for resident cells, allowing cells to maintain their phenotype and translate mechanical and chemical signals into biological responses. Importantly, this architecture is constantly remodeled by local cell populations in response to changing biochemical (systemic and local disease or injury) and mechanical (exercise, disuse, and overuse) stimuli. Here, we review the current understanding of matrix remodeling throughout life, focusing on formation and assembly during the postnatal period, maintenance and homeostasis during adulthood, and changes to homeostasis in natural aging. We also discuss advances in model systems and novel tools for studying collagen and non-collagenous matrix remodeling throughout life, and finally conclude by identifying key questions that have yet to be answered.
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Affiliation(s)
| | - Danae E Zamboulis
- Institute of Life Course and Medical Sciences, Faculty of Health and Life Sciences, University of Liverpool, Liverpool, UK
| | - Chavaunne T Thorpe
- Comparative Biomedical Sciences, The Royal Veterinary College, University of London, London, UK
| | - Jeffrey W Ruberti
- Department of Bioengineering, Northeastern University, Boston, MA, USA
| | - Brianne K Connizzo
- Department of Biomedical Engineering, Boston University, Boston, MA, USA.
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8
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Ge X, Zhang L, Xiang G, Hu Y, Lun D. Cross-Sectional Area Measurement Techniques of Soft Tissue: A Literature Review. Orthop Surg 2020; 12:1547-1566. [PMID: 32930465 PMCID: PMC7767688 DOI: 10.1111/os.12757] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2020] [Revised: 06/19/2020] [Accepted: 06/21/2020] [Indexed: 01/08/2023] Open
Abstract
Evaluation of the biomechanical properties of soft tissues by measuring the stress-strain relationships has been the focus of numerous investigations. The accuracy of stress depends, in part, upon the determination of the cross-sectional area (CSA). However, the complex geometry and pliability of soft tissues, especially ligaments and tendons, make it difficult to obtain accurate CSA, and the development of CSA measurement methods of soft tissues continues. Early attempts to determine the CSA of soft tissues include gravimetric method, geometric approximation technique, area micrometer method, and microtomy technique. Since 1990, a series of new methods have emerged, including medical imaging techniques (e.g. magnetic resonance imaging (MRI), computed tomography (CT), and ultrasound imaging (USI)), laser techniques (e.g. the laser micrometer method, the linear laser scanner (LLS) technique, and the laser reflection system (LRS) method), molding techniques, and three-dimensional (3D) scanning techniques.
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Affiliation(s)
- Xiao‐jing Ge
- Beijing Wonderful Biomaterials Co., Ltd.BeijingChina
| | - Lei Zhang
- Beijing Wonderful Biomaterials Co., Ltd.BeijingChina
| | - Gang Xiang
- Beijing Wonderful Biomaterials Co., Ltd.BeijingChina
| | | | - Deng‐xing Lun
- Beijing Ceramic BiotechnologyBeijingChina
- Weifang People's HospitalWeifangChina
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9
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Magnusson SP, Kjaer M. The impact of loading, unloading, ageing and injury on the human tendon. J Physiol 2018; 597:1283-1298. [PMID: 29920664 DOI: 10.1113/jp275450] [Citation(s) in RCA: 106] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Accepted: 05/30/2018] [Indexed: 12/28/2022] Open
Abstract
A tendon transfers force from the contracting muscle to the skeletal system to produce movement and is therefore a crucial component of the entire muscle-tendon complex and its function. However, tendon research has for some time focused on mechanical properties without any major appreciation of potential cellular and molecular changes. At the same time, methodological developments have permitted determination of the mechanical properties of human tendons in vivo, which was previously not possible. Here we review the current understanding of how tendons respond to loading, unloading, ageing and injury from cellular, molecular and mechanical points of view. A mechanistic understanding of tendon tissue adaptation will be vital for development of adequate guidelines in physical training and rehabilitation, as well as for optimal injury treatment.
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Affiliation(s)
- S Peter Magnusson
- Institute of Sports Medicine Copenhagen, Bispebjerg Hospital, Copenhagen, NV.,Department of Physical and Occupational Therapy Bispebjerg Hospital, Copenhagen, NV.,Center for Healthy Aging, Department of Health and Medical Sciences, University of Copenhagen, Copenhagen N, Denmark
| | - Michael Kjaer
- Institute of Sports Medicine Copenhagen, Bispebjerg Hospital, Copenhagen, NV.,Center for Healthy Aging, Department of Health and Medical Sciences, University of Copenhagen, Copenhagen N, Denmark
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10
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Achilles tendon compositional and structural properties are altered after unloading by botox. Sci Rep 2017; 7:13067. [PMID: 29026107 PMCID: PMC5638919 DOI: 10.1038/s41598-017-13107-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Accepted: 09/18/2017] [Indexed: 02/07/2023] Open
Abstract
Tendon function and homeostasis rely on external loading. This study investigates the biological mechanisms behind tendon biomechanical function and how the mechanical performance is affected by reduced daily loading. The Achilles tendons of 16 weeks old female Sprague Dawley rats (n = 40) were unloaded for 5 weeks by inducing muscle paralysis with botulinum toxin injections in the right gastrocnemius and soleus muscles. The contralateral side was used as control. After harvest, the tendons underwent biomechanical testing to assess viscoelasticity (n = 30 rats) and small angle X-ray scattering to determine the structural properties of the collagen fibrils (n = 10 rats). Fourier transform infrared spectroscopy and histological staining (n = 10 rats) were performed to investigate the collagen and proteoglycan content. The results show that the stiffness increased in unloaded tendons, together with an increased collagen content. Creep and axial alignment of the collagen fibers were reduced. Stress-relaxation increased whereas hysteresis was reduced in response to unloading with botox treatment. Our findings indicate that altered matrix deposition relies on mechanical loading to reorganize the newly formed tissue, without which the viscoelastic behavior is impaired. The results demonstrate that reduced daily loading deprives tendons of their viscoelastic properties, which could increase the risk of injury.
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Abstract
Understanding of the musculoskeletal system has evolved from the collection of individual phenomena in highly selected experimental preparations under highly controlled and often unphysiological conditions. At the systems level, it is now possible to construct complete and reasonably accurate models of the kinetics and energetics of realistic muscles and to combine them to understand the dynamics of complete musculoskeletal systems performing natural behaviors. At the reductionist level, it is possible to relate most of the individual phenomena to the anatomical structures and biochemical processes that account for them. Two large challenges remain. At a systems level, neuroscience must now account for how the nervous system learns to exploit the many complex features that evolution has incorporated into muscle and limb mechanics. At a reductionist level, medicine must now account for the many forms of pathology and disability that arise from the many diseases and injuries to which this highly evolved system is inevitably prone. © 2017 American Physiological Society. Compr Physiol 7:429-462, 2017.
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Affiliation(s)
| | - Gerald E Loeb
- Department of Biomedical Engineering, University of Southern California, Los Angeles, California, USA
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12
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Dideriksen K, Boesen AP, Reitelseder S, Couppé C, Svensson R, Schjerling P, Magnusson SP, Holm L, Kjaer M. Tendon collagen synthesis declines with immobilization in elderly humans: no effect of anti-inflammatory medication. J Appl Physiol (1985) 2017; 122:273-282. [DOI: 10.1152/japplphysiol.00809.2015] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Revised: 11/23/2016] [Accepted: 12/01/2016] [Indexed: 01/23/2023] Open
Abstract
Nonsteroidal anti-inflammatory drugs (NSAIDs) are used as pain killers during periods of unloading caused by traumatic occurrences or diseases. However, it is unknown how tendon protein turnover and mechanical properties respond to unloading and subsequent reloading in elderly humans, and whether NSAID treatment would affect the tendon adaptations during such periods. Thus we studied human patellar tendon protein synthesis and mechanical properties during immobilization and subsequent rehabilitating resistance training and the influence of NSAIDs upon these parameters. Nineteen men (range 60–80 yr) were randomly assigned to NSAIDs (ibuprofen 1,200 mg/day; Ibu) or placebo (Plc). One lower limb was immobilized in a cast for 2 wk and retrained for 6 wk. Tendon collagen protein synthesis, mechanical properties, size, expression of genes related to collagen turnover and remodeling, and signal intensity (from magnetic resonance imaging) were investigated. Tendon collagen synthesis decreased ( P < 0.001), whereas tendon mechanical properties and size were generally unchanged with immobilization, and NSAIDs did not influence this. Matrix metalloproteinase-2 mRNA tended to increase ( P < 0.1) after immobilization in both groups, whereas scleraxis mRNA decreased with inactivity in the Plc group only ( P < 0.05). In elderly human tendons, collagen protein synthesis decreased after 2 wk of immobilization, whereas tendon stiffness and modulus were only marginally reduced, and NSAIDs had no influence upon this. This indicates an importance of mechanical loading for maintenance of tendon collagen turnover. However, reduced collagen production induced by short-term unloading may only marginally affect tendon mechanical properties in elderly individuals.NEW & NOTEWORTHY In elderly humans, 2 wk of inactivity reduces tendon collagen protein synthesis, while tendon stiffness and modulus are only marginally reduced, and NSAID treatment does not affect this. This indicates that mechanical loading is important for maintenance of tendon collagen turnover and that changes in collagen turnover induced by short-term immobilization may only have minor impact on the internal structures that are essential for mechanical properties in elderly tendons.
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Affiliation(s)
- Kasper Dideriksen
- Institute of Sports Medicine Copenhagen, Department of Orthopedic Surgery M, Bispebjerg Hospital and Center for Healthy Aging, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Anders P. Boesen
- Institute of Sports Medicine Copenhagen, Department of Orthopedic Surgery M, Bispebjerg Hospital and Center for Healthy Aging, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Søren Reitelseder
- Institute of Sports Medicine Copenhagen, Department of Orthopedic Surgery M, Bispebjerg Hospital and Center for Healthy Aging, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
- Institute of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark; and
| | - Christian Couppé
- Institute of Sports Medicine Copenhagen, Department of Orthopedic Surgery M, Bispebjerg Hospital and Center for Healthy Aging, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
- Department of Physical Therapy, Musculoskeletal Rehabilitation Research Unit, Bispebjerg Hospital, Denmark
| | - Rene Svensson
- Institute of Sports Medicine Copenhagen, Department of Orthopedic Surgery M, Bispebjerg Hospital and Center for Healthy Aging, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Peter Schjerling
- Institute of Sports Medicine Copenhagen, Department of Orthopedic Surgery M, Bispebjerg Hospital and Center for Healthy Aging, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - S. Peter Magnusson
- Institute of Sports Medicine Copenhagen, Department of Orthopedic Surgery M, Bispebjerg Hospital and Center for Healthy Aging, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
- Department of Physical Therapy, Musculoskeletal Rehabilitation Research Unit, Bispebjerg Hospital, Denmark
| | - Lars Holm
- Institute of Sports Medicine Copenhagen, Department of Orthopedic Surgery M, Bispebjerg Hospital and Center for Healthy Aging, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
- Institute of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark; and
| | - Michael Kjaer
- Institute of Sports Medicine Copenhagen, Department of Orthopedic Surgery M, Bispebjerg Hospital and Center for Healthy Aging, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
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Influence of Knee Immobilization on Chondrocyte Apoptosis and Histological Features of the Anterior Cruciate Ligament Insertion and Articular Cartilage in Rabbits. Int J Mol Sci 2017; 18:ijms18020253. [PMID: 28134763 PMCID: PMC5343789 DOI: 10.3390/ijms18020253] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2016] [Revised: 01/18/2017] [Accepted: 01/20/2017] [Indexed: 11/30/2022] Open
Abstract
This study examined the influence of immobilization on chondrocyte apoptosis and histological features of the anterior cruciate ligament (ACL) insertion and knee articular cartilage in rabbits. Forty-eight male Japanese white rabbits were assigned to an immobilization (n = 24) or sham (n = 24) group. Rabbits in the immobilization group underwent complete unilateral surgical knee immobilization and rabbits in the sham group underwent a sham surgery. The average thickness of the glycosaminoglycan (GAG) stained red area by safranin O staining, the chondrocyte apoptosis rate and the chondrocyte proliferation rate in the cartilage layer in the ACL insertion and the articular cartilage of the medial tibial condyle were measured at one, two, four and eight weeks in six animals from each group. In the ACL insertion, the chondrocyte apoptosis rate was higher in the immobilization group than in the sham group at two and eight weeks after surgery (p < 0.05). The chondrocyte proliferation rate gradually decreased from two weeks to eight weeks in the immobilization group. The GAG layer was thinner in the immobilization group than in the sham group at two, four and eight weeks after surgery (p < 0.05). In the articular cartilage, the chondrocyte apoptosis rate in the immobilization group was higher than in the sham group at four and eight weeks after surgery (p < 0.05). The GAG layer was significantly thinner in the immobilization group than that in the sham group at four and eight weeks after surgery (p < 0.05). Knee immobilization significantly increased chondrocyte apoptosis at two and eight weeks after surgery in the ACL insertion and at four and eight weeks after surgery in the articular cartilage of the medial tibial condyle, and decreased GAG layer thickness from two to eight weeks after surgery in the ACL insertion and from four to eight weeks after surgery in the articular cartilage.
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Barfod KW, Hansen MS, Holmich P, Troelsen A, Kristensen MT. Efficacy of early controlled motion of the ankle compared with no motion after non-operative treatment of an acute Achilles tendon rupture: study protocol for a randomized controlled trial. Trials 2016; 17:564. [PMID: 27894329 PMCID: PMC5127004 DOI: 10.1186/s13063-016-1697-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Accepted: 11/11/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Early controlled ankle motion is widely used in the non-operative treatment of acute Achilles tendon rupture, though its safety and efficacy have never been investigated in a randomized setup. The objectives of this study are to investigate if early controlled motion of the ankle affects functional and patient-reported outcomes. METHODS/DESIGN The study is performed as a blinded, randomized, controlled trial with patients allocated in a 1:1 ratio to one of two parallel groups. Patients aged from 18 to 70 years are eligible for inclusion. The intervention group performs early controlled motion of the ankle in weeks 3-8 after rupture. The control group is immobilized. In total, 130 patients will be included from one big orthopedic center over a period of 2½ years. The primary outcome is the patient-reported Achilles tendon Total Rupture Score evaluated at 12 months post-injury. Secondary outcome measures are the heel-rise work test, Achilles tendon elongation, and the rate of re-rupture. The primary analysis will be conducted as intention-to-treat analyses. DISCUSSION This trial is the first to investigate the safety and efficacy of early controlled motion in the treatment of acute Achilles tendon rupture in a randomized setup. The study uses the patient-reported outcome measure, the Achilles tendon Total Rupture Score, as the primary endpoint, as it is believed to be the best surrogate measure for the tendon's actual capability to function in everyday life. TRIAL REGISTRATION ClinicalTrials.gov: NCT02015364 . Registered on 13 December 2013.
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Affiliation(s)
- Kristoffer Weisskirchner Barfod
- Department of Orthopedic Surgery, Clinical Orthopedic Research Hvidovre, Copenhagen University Hospital Hvidovre, Kettegård Allé 30, Hvidovre, 2650, Denmark.
| | - Maria Swennergren Hansen
- Physical Medicine and Rehabilitation Research - Copenhagen (PMR-C), Department of Physiotherapy and Occupational Therapy, Copenhagen University Hospital Hvidovre, Kettegård Allé 30, Hvidovre, 2650, Denmark
| | - Per Holmich
- Sports Orthopedic Research Center - Copenhagen (SORC-C), Arthroscopic Center, Department of Orthopedic Surgery, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark
| | - Anders Troelsen
- Department of Orthopedic Surgery, Clinical Orthopedic Research Hvidovre, Copenhagen University Hospital Hvidovre, Kettegård Allé 30, Hvidovre, 2650, Denmark
| | - Morten Tange Kristensen
- Physical Medicine and Rehabilitation Research - Copenhagen (PMR-C), Department of Physiotherapy and Occupational Therapy, Copenhagen University Hospital Hvidovre, Kettegård Allé 30, Hvidovre, 2650, Denmark
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15
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Hashimoto H, Tamaki T, Hirata M, Uchiyama Y, Sato M, Mochida J. Reconstitution of the complete rupture in musculotendinous junction using skeletal muscle-derived multipotent stem cell sheet-pellets as a "bio-bond". PeerJ 2016; 4:e2231. [PMID: 27547541 PMCID: PMC4957990 DOI: 10.7717/peerj.2231] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2016] [Accepted: 06/16/2016] [Indexed: 01/11/2023] Open
Abstract
Background. Significant and/or complete rupture in the musculotendinous junction (MTJ) is a challenging lesion to treat because of the lack of reliable suture methods. Skeletal muscle-derived multipotent stem cell (Sk-MSC) sheet-pellets, which are able to reconstitute peripheral nerve and muscular/vascular tissues with robust connective tissue networks, have been applied as a “bio-bond”. Methods. Sk-MSC sheet-pellets, derived from GFP transgenic-mice after 7 days of expansion culture, were detached with EDTA to maintain cell–cell connections. A completely ruptured MTJ model was prepared in the right tibialis anterior (TA) of the recipient mice, and was covered with sheet-pellets. The left side was preserved as a contralateral control. The control group received the same amount of the cell-free medium. The sheet-pellet transplantation (SP) group was further divided into two groups; as the short term (4–8 weeks) and long term (14–18 weeks) recovery group. At each time point after transplantation, tetanic tension output was measured through the electrical stimulation of the sciatic nerve. The behavior of engrafted GFP+ tissues and cells was analyzed by fluorescence immunohistochemistry. Results. The SP short term recovery group showed average 64% recovery of muscle mass, and 36% recovery of tetanic tension output relative to the contralateral side. Then, the SP long term recovery group showed increased recovery of average muscle mass (77%) and tetanic tension output (49%). However, the control group showed no recovery of continuity between muscle and tendon, and demonstrated increased muscle atrophy, with coalescence to the tibia during 4–8 weeks after operation. Histological evidence also supported the above functional recovery of SP group. Engrafted Sk-MSCs primarily formed the connective tissues and muscle fibers, including nerve-vascular networks, and bridged the ruptured tendon–muscle fiber units, with differentiation into skeletal muscle cells, Schwann cells, vascular smooth muscle, and endothelial cells. Discussion. This bridging capacity between tendon and muscle fibers of the Sk-MSC sheet-pellet, as a “bio-bond,” represents a possible treatment for various MTJ ruptures following surgery.
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Affiliation(s)
- Hiroyuki Hashimoto
- Department of Orthopaedic, Tokai University School of Medicine, Isehara, Japan; Muscle Physiology and Cell Biology Unit, Tokai University School of Medicine, Isehara, Japan
| | - Tetsuro Tamaki
- Muscle Physiology and Cell Biology Unit, Tokai University School of Medicine, Isehara, Japan; Department of Human Structure and Function, Tokai University School of Medicine, Isehara, Japan
| | - Maki Hirata
- Department of Orthopaedic, Tokai University School of Medicine, Isehara, Japan; Muscle Physiology and Cell Biology Unit, Tokai University School of Medicine, Isehara, Japan
| | - Yoshiyasu Uchiyama
- Department of Orthopaedic, Tokai University School of Medicine, Isehara, Japan; Muscle Physiology and Cell Biology Unit, Tokai University School of Medicine, Isehara, Japan
| | - Masato Sato
- Department of Orthopaedic, Tokai University School of Medicine , Isehara , Japan
| | - Joji Mochida
- Department of Orthopaedic, Tokai University School of Medicine , Isehara , Japan
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16
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Eriksen C, Svensson RB, Scheijen J, Hag AMF, Schalkwijk C, Praet SFE, Schjerling P, Kjær M, Magnusson SP, Couppé C. Systemic stiffening of mouse tail tendon is related to dietary advanced glycation end products but not high-fat diet or cholesterol. J Appl Physiol (1985) 2014; 117:840-7. [PMID: 25103969 DOI: 10.1152/japplphysiol.00584.2014] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Tendon pathology is related to metabolic disease and mechanical overloading, but the effect of metabolic disease on tendon mechanics is unknown. This study investigated the effect of diet and apolipoprotein E deficiency (ApoE(-/-)) on mechanical properties and advanced glycation end product (AGE) cross-linking of non-weight-bearing mouse tail tendons. Twenty ApoE(-/-) male mice were used as a model for hypercholesterolemia along with 26 wild-type (WT) mice. One-half of the mice from each group was fed a normal diet (ND) and the other half was fed a high-fat diet (HFD) to induce obesity. All were killed at 40 wk, and tail tendon fascicles were mechanically tested to failure and analyzed for AGEs. Diets were also analyzed for AGEs. ApoE(-/-) mice displayed a 14% increase in plateau modulus compared with WT mice (P < 0.05), whereas HFD mice displayed a 13% decrease in plateau modulus (P < 0.05) and a 12% decrease in total modulus (P < 0.05) compared with ND mice. Tail tendons of HFD mice had significantly lower concentrations of AGEs [carboxymethyllysine (CML): 26%, P < 0.0001; methylglyoxal-derived hydroimidazolone 1 (MG-H1): 15%, P < 0.005; pentosidine: 13%, P < 0.0005]. The HFD had ∼44-fold lower content of CML (P < 0.01), ∼29-fold lower content of carboxyethyllysine (P < 0.005), and ∼16-fold lower content of MG-H1 (P < 0.05) compared with ND. ApoE(-/-) increased, whereas HFD decreased mouse tail tendon stiffness. Dietary AGE content may be a crucial determinant for accumulation of AGE cross-links in tendons and for tissue compliance. The results demonstrate how systemic metabolic factors may influence tendon health.
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Affiliation(s)
- C Eriksen
- 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, Denmark
| | - R B Svensson
- 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, Denmark
| | - J Scheijen
- Department of Internal Medicine and Cardiovascular Research Institute Maastricht, Maastricht University Medical Center, The Netherlands
| | - A M F Hag
- Cluster for Molecular Imaging, Faculty of Health and Medical Sciences and Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, University of Copenhagen, Denmark
| | - C Schalkwijk
- Department of Internal Medicine and Cardiovascular Research Institute Maastricht, Maastricht University Medical Center, The Netherlands
| | - S F E Praet
- Department of Rehabilitation Medicine, MOVEFIT- Sports medicine, Erasmus University Medical Centre, Rotterdam, The Netherlands; and
| | - P 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, Denmark
| | - M Kjær
- 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, Denmark
| | - S P Magnusson
- 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, Denmark; Department of Physical Therapy, Musculoskeletal Rehabilitation Research Unit, Bispebjerg Hospital, Denmark
| | - C Couppé
- 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, Denmark; Department of Physical Therapy, Musculoskeletal Rehabilitation Research Unit, Bispebjerg Hospital, Denmark
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17
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Boesen AP, Dideriksen K, Couppé C, Magnusson SP, Schjerling P, Boesen M, Aagaard P, Kjaer M, Langberg H. Effect of growth hormone on aging connective tissue in muscle and tendon: gene expression, morphology, and function following immobilization and rehabilitation. J Appl Physiol (1985) 2014; 116:192-203. [DOI: 10.1152/japplphysiol.01077.2013] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
It is unknown whether loss in musculotendinous tissue during inactivity can be counteracted by growth hormone (GH), and whether GH accelerate rehabilitation in aging individuals. Elderly men (65–75 yr; n = 12) had one leg immobilized 2 wk followed by 6 wk of retraining and were randomly assigned to daily injections of recombinant GH (rhGH; n = 6) or placebo (Plc; n = 6). Cross-sectional area (CSA), muscle strength (MVC), and biomechanical properties of m. quadriceps and patellar tendon were determined. Muscle and tendon biopsies were analyzed for gene expressions (mRNA) of collagen (COL1A1/3A1) and insulin-like growth factors (IGF-1Ea/Ec). Fibril morphology was analyzed by transmission electron microscope (TEM). In tendon, CSA and biomechanical properties did not change following immobilization, but an increase in CSA was found after 6 wk of rehabilitation in both groups. The changes were more pronounced when GH was injected. Furthermore, tendon stiffness increased in the GH group. Muscle CSA declined after immobilization in the Plc but not in the GH group. Muscle CSA increased during retraining, with a significantly larger increase in the GH group compared with the Plc group. Both a time and a group effect were seen for IGF-1Ea/Ec and COL1A1/3A1 mRNA expression in muscle, with a difference between GH and Plc. IGF-1Ea/Ec and COL-1A1/3A1 mRNA expression increased in muscle following immobilization and retraining in subjects receiving GH, whereas an increase in IGF-1Ec mRNA expression was seen in the Plc group only after retraining. In conclusion, in elderly humans, GH seems to have a matrix stabilizing effect during inactivity and rehabilitation by stimulating collagen expression in the musculotendinous tissue and increasing tendon CSA and stiffness.
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Affiliation(s)
- A. P. Boesen
- Department of Ortopaedic Surgery M, Institute of Sports Medicine Copenhagen, Bispebjerg Hospital, and Center for Healthy Aging, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - K. Dideriksen
- Department of Ortopaedic Surgery M, Institute of Sports Medicine Copenhagen, Bispebjerg Hospital, and Center for Healthy Aging, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - C. Couppé
- Department of Ortopaedic Surgery M, Institute of Sports Medicine Copenhagen, Bispebjerg Hospital, and Center for Healthy Aging, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Department of Physical Therapy, Bispebjerg Hospital, Copenhagen, Denmark
| | - S. P. Magnusson
- Department of Ortopaedic Surgery M, Institute of Sports Medicine Copenhagen, Bispebjerg Hospital, and Center for Healthy Aging, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Department of Physical Therapy, Bispebjerg Hospital, Copenhagen, Denmark
| | - P. Schjerling
- Department of Ortopaedic Surgery M, Institute of Sports Medicine Copenhagen, Bispebjerg Hospital, and Center for Healthy Aging, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - M. Boesen
- Department of Radiology, Bispebjerg and Frederiksberg Hospital, Copenhagen, Denmark
| | - P. Aagaard
- Institute of Exercise Physiology and Clinical Biomechanics, SDU Muscle Research Cluster (SMRC), University of Southern Denmark, Odense, Denmark; and
| | - M. Kjaer
- Department of Ortopaedic Surgery M, Institute of Sports Medicine Copenhagen, Bispebjerg Hospital, and Center for Healthy Aging, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - H. Langberg
- Department of Ortopaedic Surgery M, Institute of Sports Medicine Copenhagen, Bispebjerg Hospital, and Center for Healthy Aging, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Department of Public Health, CopenRehab, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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18
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Min Y, Seo JH, Kwon YB, Lee MH. Effect of the position of immobilization upon the tensile properties in injured achilles tendon of rat. Ann Rehabil Med 2013; 37:1-9. [PMID: 23525566 PMCID: PMC3604217 DOI: 10.5535/arm.2013.37.1.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2012] [Accepted: 09/05/2012] [Indexed: 11/11/2022] Open
Abstract
Objective To examine the effect of the posture of immobilization upon the tensile properties in injured Achilles tendon of rat for an initial period of immobilization. Methods Forty-two Sprague-Dawley rats were used in the present study. Eighteen rats received a total tenotomy of the right Achilles tendon to mimic total rupture and were divided into three groups comprising of 6 rats each. Ankles of group A were immobilized at 60° of plantarflexion. Ankles of group B were immobilized at neutral position. Whereas, those of group C were immobilized at 60° of dorsiflexion. Other 18 rats received hemitenotomy to mimic partial rupture and were divided into three groups. The remaining 6 rats were kept free as control. After 14 days, we dissected the tendons and analyzed maximum force, stiffness, and energy uptake during pulling of the tendons until they ruptured. The tendons of 6 rats in each group and control were reserved for histology. Picrosirius staining was done for the analysis of collagen organization. Results In total tenotomy, tensile properties were significantly different between the control and the intervention groups (p<0.05). Group C showed relatively higher values than the groups A and B with respect to tensile properties (p>0.05). In partial tenotomy, tensile properties were significantly different between the control and the intervention groups (p<0.05). Group C showed significantly higher value than other intervention groups in terms of maximum force and energy uptake (p<0.05). The semiquantitative histologic grading scores were assigned for collagen organization. The scores for dorsiflexion posture were higher than the ones for plantarflexion. Conclusion Dorsiflexion posture in partial ruptured Achilles tendon showed better functional recovery than other immobilized postures. In total ruptured case, the tensile properties showed increasing tendency in dorsiflexion posture.
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Affiliation(s)
- Yong Min
- Department of Physical Medicine and Rehabilitation, Institute for Medical Sciences, Chonbuk National University Medical School and Research Institute of Clinical Medicine, Chonbuk National University Hospital, Jeonju, Korea
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19
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Matson A, Konow N, Miller S, Konow PP, Roberts TJ. Tendon material properties vary and are interdependent among turkey hindlimb muscles. ACTA ACUST UNITED AC 2012; 215:3552-8. [PMID: 22771746 DOI: 10.1242/jeb.072728] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The material properties of a tendon affect its ability to store and return elastic energy, resist damage, provide mechanical feedback and amplify or attenuate muscle power. While the structural properties of a tendon are known to respond to a variety of stimuli, the extent to which material properties vary among individual muscles remains unclear. We studied the tendons of six different muscles in the hindlimb of Eastern wild turkeys to determine whether there was variation in elastic modulus, ultimate tensile strength and resilience. A hydraulic testing machine was used to measure tendon force during quasi-static lengthening, and a stress-strain curve was constructed. There was substantial variation in tendon material properties among different muscles. Average elastic modulus differed significantly between some tendons, and values for the six different tendons varied nearly twofold, from 829±140 to 1479±106 MPa. Tendons were stretched to failure, and the stress at failure, or ultimate tensile stress, was taken as a lower-limit estimate of tendon strength. Breaking tests for four of the tendons revealed significant variation in ultimate tensile stress, ranging from 66.83±14.34 to 112.37±9.39 MPa. Resilience, or the fraction of energy returned in cyclic length changes was generally high, and one of the four tendons tested was significantly different in resilience from the other tendons (range: 90.65±0.83 to 94.02±0.71%). An analysis of correlation between material properties revealed a positive relationship between ultimate tensile strength and elastic modulus (r(2)=0.79). Specifically, stiffer tendons were stronger, and we suggest that this correlation results from a constrained value of breaking strain, which did not vary significantly among tendons. This finding suggests an interdependence of material properties that may have a structural basis and may explain some adaptive responses observed in studies of tendon plasticity.
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Affiliation(s)
- Andrew Matson
- Department of Ecology and Evolutionary Biology, Brown University, Providence, RI 02912, USA
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20
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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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Kinugasa R, Hodgson JA, Edgerton VR, Shin DD, Sinha S. Reduction in tendon elasticity from unloading is unrelated to its hypertrophy. J Appl Physiol (1985) 2010; 109:870-7. [PMID: 20616227 DOI: 10.1152/japplphysiol.00384.2010] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Tendinous tissues respond to chronic unloading with adaptive changes in mechanical, elastic, and morphological properties. However, little is known about the changes in the detailed structures of the entire tendinous tissue and whether the change in tendon stiffness is related to morphology. We investigated changes in dimensional (volume, cross-sectional area, segmented lengths) and elastic (Young's modulus) properties of the Achilles tendon and distal aponeurosis in response to chronic unilateral lower limb suspension (ULLS) using velocity encoded phase contrast (VE-PC) and three-dimensional morphometric magnetic resonance imaging (MRI). Five healthy subjects underwent ULLS for 4 wk. Axial morphometric MRI was acquired along the entire length from the calcaneous to the medial gastrocnemius insertion. An oblique sagittal VE-PC MRI was also acquired. The Young's modulus could be calculated from this cine dynamic sequence of velocity encoded images from the slope of the stress-strain curve during the submaximal isometric plantar flexion. After 4 wk of ULLS, we found significant (46.7%) decrease in maximum plantar flexion torque. The total volumes of entire tendinous tissue (determined as the sum of the Achilles tendon and distal aponeurosis) increased significantly by 6.4% (11.9 vs. 12.7 ml) after ULLS. In contrast, Young's modulus decreased significantly by 10.4% (211.7 vs. 189.6 MPa) for the Achilles tendon and 29.0% for the distal aponeurosis (158.8 vs. 113.0 MPa) following ULLS. There was no significant correlation between relative change in volume and Young's modulus with 4 wk of ULLS. It is suggested that, although tendon hypertrophy can be expected to adversely affect tendon stiffness, the absence of any significant correlation between the magnitude of tendon hypertrophy and reduced Young's modulus indicates that dimensional factors were not critical to the elastic properties.
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Affiliation(s)
- Ryuta Kinugasa
- Faculty of Sport Sciences, Waseda University, Saitama, Japan
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22
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Kjaer M, Langberg H, Heinemeier K, Bayer ML, Hansen M, Holm L, Doessing S, Kongsgaard M, Krogsgaard MR, Magnusson SP. From mechanical loading to collagen synthesis, structural changes and function in human tendon. Scand J Med Sci Sports 2010; 19:500-10. [PMID: 19706001 DOI: 10.1111/j.1600-0838.2009.00986.x] [Citation(s) in RCA: 187] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The adaptive response of connective tissue to loading requires increased synthesis and turnover of matrix proteins, with special emphasis on collagen. Collagen formation and degradation in the tendon increases with both acute and chronic loading, and data suggest that a gender difference exists, in that females respond less than males with regard to an increase in collagen formation after exercise. It is suggested that estrogen may contribute toward a diminished collagen synthesis response in females. Conversely, the stimulation of collagen synthesis by other growth factors can be shown in both animal and human models where insulin-like growth factor 1 (IGF-I) and transforming growth factor-beta-1 (TGF-beta-1) expression increases to accompany or precede an increase in procollagen expression and collagen synthesis. In humans, it can be demonstrated that an increase in the interstitial concentration of TGF-beta, PGE2, IGF-I plus its binding proteins and interleukin-6 takes place after exercise. The increase in IGF-I expression in tendon includes the isoform that has so far been thought only to exist in skeletal muscle (mechano growth factor). The increase in IGF-I and procollagen expression showed a similar response whether the tendon was stimulated by concentric, isometric or eccentric muscle contraction, suggesting that strain rather that stress/torque determines the collagen-synthesis stimulating response seen with exercise. The adaptation time to chronic loading is longer in tendon tissue compared with contractile elements of skeletal muscle or the heart, and only with very prolonged loading are significant changes in gross dimensions of the tendon observed, suggesting that habitual loading is associated with a robust change in the size and mechanical properties of human tendons. An intimate interplay between mechanical signalling and biochemical changes in the matrix is needed in tendon, such that chemical changes can be converted into adaptations in the morphology, structure and material properties.
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Affiliation(s)
- M Kjaer
- Department of Orthopaedics, Institute of Sports Medicine, Bispebjerg Hospital, Copenhagen, Denmark.
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23
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Andersson T, Eliasson P, Aspenberg P. Tissue memory in healing tendons: short loading episodes stimulate healing. J Appl Physiol (1985) 2009; 107:417-21. [PMID: 19541735 DOI: 10.1152/japplphysiol.00414.2009] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Intact tendons adapt slowly to changes in mechanical loading, whereas in healing tendons the effect of mechanical loading or its absence is dramatic. The longevity of the response to a single loading episode is, however, unknown. We hypothesized that the tissue has a "memory" of loading episodes and that therefore short loadings are sufficient to elicit improved healing. The Achilles tendon of 70 female rats was transected and unloaded by tail suspension for 12 days (suspension started on day 2 after surgery). Each day, the rats were let down from suspension for short daily training episodes according to different regimes: 15 min of cage activity or treadmill running for 15, 30, 60, or 2x15 min. Rats with transected Achilles tendons and full-time cage activity served as controls. The results demonstrated that full-time cage activity increased the peak force over three times compared with unloading. Short daily loading episodes (treadmill running) increased the peak force about half as much as full-time activity. Prolongation of treadmill running above 15 min or dividing the daily training in two separate episodes had minimal further effect. This mechanical stimulation increased the cross-sectional area but had no effect on the mechanical properties of the repair tissue. The findings indicate that once the tissue had received information from a certain loading type and level, this is "memorized" and leads to a response lasting many hours. This suggests that patients might be allowed early short loading episodes following, e.g., an Achilles tendon rupture for a better outcome.
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Affiliation(s)
- Therese Andersson
- Orthopedics and Sports Medicine, AIR/IKE, Faculty of Health Sciences, Linkoping University, SE 581 83 Linkoping, Sweden
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24
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Heinemeier KM, Olesen JL, Haddad F, Schjerling P, Baldwin KM, Kjaer M. Effect of unloading followed by reloading on expression of collagen and related growth factors in rat tendon and muscle. J Appl Physiol (1985) 2008; 106:178-86. [PMID: 18988763 DOI: 10.1152/japplphysiol.91092.2008] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Tendon tissue and the extracellular matrix of skeletal muscle respond to mechanical loading by increased collagen expression and synthesis. This response is likely a secondary effect of a mechanically induced expression of growth factors, including transforming growth factor-beta1 (TGF-beta1) and insulin-like growth factor-I (IGF-I). It is not known whether unloading of tendon tissue can reduce the expression of collagen and collagen-inducing growth factors. Furthermore, the coordinated response of tendon and muscle tissue to disuse, followed by reloading, is unclear. Female Sprague-Dawley rats were subjected to hindlimb suspension (HS) for 7 or 14 days, followed by 2, 4, 8, or 16 days of reload (RL) (n = 8 in each group). Age-matched controls were included for day 0, day 14 HS, and day 16 RL (n = 8). mRNA expression levels for collagen I (COL1A1), collagen III (COL3A1), TGF-beta1, connective tissue growth factor (CTGF), myostatin, and IGF-I isoforms were measured by real-time RT-PCR in Achilles tendon and soleus muscle. The tendon mass was unchanged, while the muscle mass was reduced by 50% after HS (P < 0.05) and returned to control levels during RL. Collagen I and III, TGF-beta1, and CTGF mRNA levels were unaltered by HS, although collagen III tended to decrease in muscle at day 7 HS. IGF-I isoforms were significantly induced in tendon after 7 days of HS (P < 0.001), and mechanogrowth factor increased in muscle at day 14 HS (P < 0.05). Reload increased muscle collagen I and III mRNA (>10-fold) (P < 0.001) and growth factor expression (P < 0.05), while the tendon response was limited to a moderate induction of collagen expression (2-fold) (P < 0.05). Unloading of tendon and muscle tissue did not reduce expression of collagen and collagen-inducing growth factors, indicating that the response to unloading is not opposite that of loading. Furthermore, the tendon response was clearly different and less pronounced than the muscle tissue response.
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Affiliation(s)
- K M Heinemeier
- Institute of Sports Medicine, Bispebjerg Hospital, DK-2400 Copenhagen NV, Denmark.
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25
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Christensen B, Dyrberg E, Aagaard P, Kjaer M, Langberg H. Short-term immobilization and recovery affect skeletal muscle but not collagen tissue turnover in humans. J Appl Physiol (1985) 2008; 105:1845-51. [PMID: 18927270 DOI: 10.1152/japplphysiol.90445.2008] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Not much is known about the effects of immobilization and subsequent recovery on tendon connective tissue. In the present study, healthy young men had their nondominant leg immobilized for a 2-wk period, followed by a recovery period of the same length. Immobilization resulted in a mean decrease of 6% (5,413 to 5,077 mm(2)) in cross-sectional area (CSA) of the triceps surae muscles and a mean decrease of 9% (261 to 238 N.m) in strength of the immobilized calf muscles. Two weeks of recovery resulted in a 6% increased in CSA (to 5,367 mm(2)), whereas strength remained suppressed (240 N.m). No difference in Achilles tendon CSA was detected between the two legs at any time point. Local tendon collagen synthesis, measured as the peritendinous concentrations of PINP (NH(2)-terminal propeptide of type I collagen; indirect marker for collagen synthesis), was unchanged after 2 wk of immobilization. However, peritendinous levels of PINP were significantly elevated in the immobilized leg (15 to 139 ng/ml) following 2 wk of remobilization compared with preimmobilization levels. In contradiction hereto, systemic concentrations of PINP remained unchanged throughout the study. Immobilization reduced muscle size and strength, while tendon size and collagen turnover were unchanged. While recovery resulted in an increase in muscle size, strength was unchanged. No significant difference in tendon size could be detected between the two legs after 2 wk of recovery, although collagen synthesis was increased in the previously immobilized leg. Thus 2 wk of immobilization are sufficient to induce significant changes in muscle tissue, whereas tendon tissue seems to be more resistant to short-term immobilization.
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Affiliation(s)
- Britt Christensen
- Institute of Sports Medicine Copenhagen, Bispebjerg Hospital, Bispebjerg Bakke 23, 2400 Copenhagen NV, Denmark
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26
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Leigh DR, Abreu EL, Derwin KA. Changes in gene expression of individual matrix metalloproteinases differ in response to mechanical unloading of tendon fascicles in explant culture. J Orthop Res 2008; 26:1306-12. [PMID: 18404723 PMCID: PMC6100787 DOI: 10.1002/jor.20650] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Immobilization of the tendon and ligament has been shown to result in a rapid and significant decrease in material properties. It has been proposed that tissue degradation leading to tendon rupture or pain in humans may also be linked to mechanical unloading following focal tendon injury. Hence, understanding the remodeling mechanism associated with mechanical unloading has relevance for the human conditions of immobilization (e.g., casting), delayed repair of tendon ruptures, and potentially overuse injuries as well. This is the first study to investigate the time course of gene expression changes associated with tissue harvest and mechanical unloading culture in an explant model. Rat tail tendon fascicles were harvested and placed in culture unloaded for up to 48 h and then evaluated using qRT-PCR for changes in two anabolic and four catabolic genes at 12 time points. Our data demonstrates that Type I Collagen, Decorin, Cathepsin K, and MMP2 gene expression are relatively insensitive to unloaded culture conditions. However, changes in both MMP3 and MMP13 gene expression are rapid, dramatic, sustained, and changing during at least the first 48 h of unloaded culture. This data will help to further elucidate the mechanism for the loss of mechanical properties associated with mechanical unloading in tendon.
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Affiliation(s)
- Diane R. Leigh
- Department of Biomedical Engineering and the Orthopaedic Research Center, Lerner Research Institute, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, Ohio 44195
| | - Eduardo L. Abreu
- Department of Orthopaedic Surgery, Children’s Hospital of Boston, 300 Longwood Avenue, Enders 1022, Boston, Massachusetts
| | - Kathleen A. Derwin
- Department of Biomedical Engineering and the Orthopaedic Research Center, Lerner Research Institute, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, Ohio 44195
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27
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Christensen B, Dyrberg E, Aagaard P, Enehjelm S, Krogsgaard M, Kjaer M, Langberg H. Effects of long-term immobilization and recovery on human triceps surae and collagen turnover in the Achilles tendon in patients with healing ankle fracture. J Appl Physiol (1985) 2008; 105:420-6. [PMID: 18403455 DOI: 10.1152/japplphysiol.00201.2008] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The aim of the present study was to analyze how human tendon connective tissue responds to an approximately 7-wk period of immobilization and a remobilization period of a similar length, in patients with unilateral ankle fracture, which is currently unknown. Calf muscle cross-sectional area (CSA) decreased by 15% (5,316 to 4,517 mm2) and strength by 54% (239 to 110 N.m) in the immobilized leg after 7 wk. During the 7-wk remobilization, the CSA increased by 9% (to 4,943 mm2) and strength by 37% (to 176 Nm). Achilles tendon CSA did not change significantly during either immobilization or remobilization. Local collagen turnover was measured as the peritendinous concentrations of NH2-terminal propeptide of type I collagen (PINP) and COOH-terminal telopeptide region of type I collagen (ICTP), markers thought to be indexes of type I collagen synthesis and degradation, respectively. Both markers were increased (PINP: 257 vs. 56 ng/ml; ICTP: 9.8 vs. 2.1 microg/l) in the immobilized leg compared with the control leg after the 7 wk of immobilization, and levels decreased again in the immobilized leg during the recovery period (PINP: 103 vs. 44 ng/ml; ICTP: 4.2 vs. 1.9 microg/l). A significant reduction in calf muscle CSA and strength was found in relation to 7 wk of immobilization. Immobilization increased both collagen synthesis and degradation in tendon near tissue. However, it cannot be excluded that the facture of the ankle in close proximity could have affected these data. Remobilization increased muscle size and strength and tendon synthesis and degradation decreased to baseline levels. These dynamic changes in tendon connective tissue turnover were not associated with macroscopic changes in tendon size.
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Affiliation(s)
- Britt Christensen
- Institute of Sports Medicine, Bispebjerg Hospital, University of Copenhagen, Bispebjerg Bakke 23, 2400 Copenhagen NV, Denmark
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28
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Eliasson P, Fahlgren A, Pasternak B, Aspenberg P. Unloaded rat Achilles tendons continue to grow, but lose viscoelasticity. J Appl Physiol (1985) 2007; 103:459-63. [PMID: 17412787 DOI: 10.1152/japplphysiol.01333.2006] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Tendons can function as springs and thereby preserve energy during cyclic loading. They might also have damping properties, which, hypothetically, could reduce risk of microinjuries due to fatigue at sites of local stress concentration within the tendon. At mechanical testing, damping will appear as hysteresis. How is damping influenced by training or disuse? Does training decrease hysteresis, thereby making the tendon a better spring, or increase hysteresis and thus improve damping? Seventy-eight female 10-wk-old Sprague-Dawley rats were randomized to three groups. Two groups had botulinum toxin injected into the calf muscles to unload the left Achilles tendon through muscle paralysis. One of these groups was given doxycycline, as a systemic matrix metalloproteinase inhibitor. The third group served as loaded controls. The Achilles tendons were harvested after 1 or 6 wk for biomechanical testing. An increase with time was seen in tendon dry weight, wet weight, water content, transverse area, length, stiffness, force at failure, and energy uptake in all three groups ( P < 0.001 for each parameter). Disuse had no effect on these parameters. Creep was decreased with time in all groups. The only significant effect of disuse was on hysteresis ( P = 0.004) and creep ( P = 0.007), which both decreased with disuse compared with control, and on modulus, which was increased ( P = 0.008). Normalized glycosaminoglycan content was unaffected by time and disuse. No effect of doxycycline was observed. The results suggest that in growing animals, the tendons continue to grow regardless of mechanical loading history, whereas maintenance of damping properties requires mechanical stimulation.
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Affiliation(s)
- Pernilla Eliasson
- Division of Orthopaedics, Department of Neuroscience and Locomotion, Faculty of Health Sciences, Linköping University, Linköping, Sweden
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29
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de Boer MD, Maganaris CN, Seynnes OR, Rennie MJ, Narici MV. Time course of muscular, neural and tendinous adaptations to 23 day unilateral lower-limb suspension in young men. J Physiol 2007; 583:1079-91. [PMID: 17656438 PMCID: PMC2277190 DOI: 10.1113/jphysiol.2007.135392] [Citation(s) in RCA: 194] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Muscles and tendons are highly adaptive to changes in chronic loading, though little is known about the adaptative time course. We tested the hypothesis that, in response to unilateral lower limb suspension (ULLS), the magnitude of tendon mechanical adaptations would match or exceed those of skeletal muscle. Seventeen men (1.79 +/- 0.05 m, 76.6 +/- 10.3 kg, 22.3 +/- 3.8 years) underwent ULLS for 23 days (n = 9) or acted as controls (n = 8). Knee extensor (KE) torque, voluntary activation (VA), cross-sectional area (CSA) (by magnetic resonance imaging), vastus lateralis fascicle length (L(f)) and pennation angle (), patellar tendon stiffness and Young's modulus (by ultrasonography) were measured before, during and at the end of ULLS. After 14 and 23 days (i) KE torque decreased by 14.8 +/- 5.5% (P < 0.001) and 21.0 +/- 7.1% (P < 0.001), respectively; (ii) VA did not change; (iii) KE CSA decreased by 5.2 +/- 0.7% (P < 0.001) and 10.0 +/- 2.0% (P < 0.001), respectively; L(f) decreased by 5.9% (n.s.) and 7.7% (P < 0.05), respectively, and by 3.2% (P < 0.05) and 7.6% (P < 0.01); (iv) tendon stiffness decreased by 9.8 +/- 8.2% (P < 0.05) and 29.3 +/- 11.5% (P < 0.005), respectively, and Young's modulus by 9.2 +/- 8.2% (P < 0.05) and 30.1 +/- 11.9% (P < 0.01), respectively, with no changes in the controls. Hence, ULLS induces rapid losses of KE muscle size, architecture and function, but not in neural drive. Significant deterioration in tendon mechanical properties also occurs within 2 weeks, exacerbating in the third week of ULLS. Rehabilitation to limit muscle and tendon deterioration should probably start within 2 weeks of unloading.
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Affiliation(s)
- Maarten D de Boer
- Manchester Metropolitan University, Institute for Biophysical and Clinical Research into Human Movement, Alsager ST7 2HL, UK.
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30
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Aspenberg P. Stimulation of tendon repair: mechanical loading, GDFs and platelets. A mini-review. INTERNATIONAL ORTHOPAEDICS 2007; 31:783-9. [PMID: 17583812 PMCID: PMC2266668 DOI: 10.1007/s00264-007-0398-6] [Citation(s) in RCA: 118] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2007] [Revised: 04/25/2007] [Accepted: 04/25/2007] [Indexed: 12/11/2022]
Abstract
The repair of subcutaneous tendon ruptures can be stimulated by a single application of one of several growth factors [e.g. platelet-derived growth factor (PDGF), transforming growth factor (TGF)-beta, insulin-like growth factor (IGF)-1, vascular endothelial growth factor (VEGF), bone morphogenetic proteins (BMPs) like growth differentiation factor (GDF)-5, -6, -7] or by a thrombocyte concentrate (PRP). The response to these measures is dependent on the mechanical microenvironment, which is crucial for repair. So far, almost all research has been limited to rodent models, mostly using the rat Achilles tendon. Ruptured human Achilles tendons appear to be mechanically loaded in spite of immobilisation. This suggests that the mechanical microenvironment might be favourable for the clinical use of growth factors or platelets for this indication. New methods to quantitate human Achilles tendon repair have been developed.
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Affiliation(s)
- Per Aspenberg
- Section for Orthopaedics, Inst. for Neuroscience and Locomotion, Faculty of Health Sciences, Linköping University, 581 85, Linköping, Sweden,
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31
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Narici MV, Maganaris CN. Adaptability of elderly human muscles and tendons to increased loading. J Anat 2006; 208:433-43. [PMID: 16637869 PMCID: PMC2100204 DOI: 10.1111/j.1469-7580.2006.00548.x] [Citation(s) in RCA: 105] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Senile sarcopenia, the loss of muscle mass associated with aging, is one of the main causes of muscle weakness and reduced locomotor ability in old age. Although this condition is mainly driven by neuropathic processes, nutritional, hormonal and immunological factors, as well as a reduction in physical activity, contribute to this phenomenon. Sarcopenia alone, however, does not fully account for the observed muscle weakness, as the loss of force is greater than that accounted for by the decrease in muscle size. As a consequence, a reduction in the force per unit area, both at single fibre and at whole muscle level, is observed. We recently suggested that at whole muscle level, this reduction in intrinsic force is the result of the combined effect of changes in (1) muscle architecture, (2) tendon mechanical properties, (3) neural drive (reduced agonist and increased antagonist muscle activity) and (4) single fibre-specific tension. Whereas several studies support the role of the last two factors in the loss of intrinsic muscle force with aging, alterations in muscle architecture and in tendon mechanical properties have also been shown to contribute to the above phenomenon. Indeed, sarcopenia of the human plantarflexors, represented by a 25% reduction in muscle volume, was found to be associated with a 10% reduction in fibre fascicle length and 13% reduction in pennation angle. These architectural alterations were accompanied by a 10% decrease in tendon stiffness, attributable to alterations in tendon material properties, as suggested by a 14% decrease in Young's modulus. Most of these changes may be reversed by 14 weeks of resistive training; both fibre fascicle length and tendon stiffness were found to be increased by 10 and 64%, respectively. Surprisingly, however, training had no effect on the estimated relative length-tension properties of the muscle, indicating that the effects of greater tendon stiffness and increased fascicle length cancelled out each other. It seems that natural strategies may be in place to ensure that the relative operating range of muscle remains unaltered by changes in physical activity, in old age.
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Affiliation(s)
- Marco V Narici
- Institute for Biophysical and Clinical Research into Human Movement, Manchester Metropolitan University, Cheshire, UK.
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