1
|
Nakamichi R, Asahara H. The role of mechanotransduction in tendon. J Bone Miner Res 2024; 39:814-820. [PMID: 38795012 DOI: 10.1093/jbmr/zjae074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Revised: 04/04/2024] [Accepted: 05/24/2024] [Indexed: 05/27/2024]
Abstract
Tendons play an important role in the maintenance of motor function by connecting muscles and bones and transmitting forces. Particularly, the role of mechanical stress has primarily focused on the key mechanism of tendon homeostasis, with much research on this topic. With the recent development of molecular biological techniques, the mechanisms of mechanical stress sensing and signal transduction have been gradually elucidated with the identification of mechanosensor in tendon cells and the master regulator in tendon development. This review provides a comprehensive overview of the structure and function of tendon tissue, including the role for physical performance and the detailed mechanism of mechanotransduction in its regulation. An important lesson is that the role of mechanotransduction in tendon tissue is only partially clarified, indicating the complexity of the mechanisms of motor function and fueling increasing interest in uncovering these mechanisms.
Collapse
Affiliation(s)
- Ryo Nakamichi
- Department of Molecular and Cellular Biology, Scripps Research, 10550 North Torrey Pines Road, MBB-102, La Jolla, CA 92037, United States
- Department of Systems Biomedicine, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-Ku, Tokyo 113-8510, Japan
- Department of Orthopaedic Surgery, Okayama University hospital, 2-5-1 Shikata-Cho, Kita-Ku, Okayama 700-8558, Japan
| | - Hiroshi Asahara
- Department of Molecular and Cellular Biology, Scripps Research, 10550 North Torrey Pines Road, MBB-102, La Jolla, CA 92037, United States
- Department of Systems Biomedicine, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-Ku, Tokyo 113-8510, Japan
| |
Collapse
|
2
|
Nakamichi R, Ma S, Nonoyama T, Chiba T, Kurimoto R, Ohzono H, Olmer M, Shukunami C, Fuku N, Wang G, Morrison E, Pitsiladis YP, Ozaki T, D'Lima D, Lotz M, Patapoutian A, Asahara H. The mechanosensitive ion channel PIEZO1 is expressed in tendons and regulates physical performance. Sci Transl Med 2022; 14:eabj5557. [PMID: 35648809 DOI: 10.1126/scitranslmed.abj5557] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
How mechanical stress affects physical performance via tendons is not fully understood. Piezo1 is a mechanosensitive ion channel, and E756del PIEZO1 was recently found as a gain-of-function variant that is common in individuals of African descent. We generated tendon-specific knock-in mice using R2482H Piezo1, a mouse gain-of-function variant, and found that they had higher jumping abilities and faster running speeds than wild-type or muscle-specific knock-in mice. These phenotypes were associated with enhanced tendon anabolism via an increase in tendon-specific transcription factors, Mohawk and Scleraxis, but there was no evidence of changes in muscle. Biomechanical analysis showed that the tendons of R2482H Piezo1 mice were more compliant and stored more elastic energy, consistent with the enhancement of jumping ability. These phenotypes were replicated in mice with tendon-specific R2482H Piezo1 replacement after tendon maturation, indicating that PIEZO1 could be a target for promoting physical performance by enhancing function in mature tendon. The frequency of E756del PIEZO1 was higher in sprinters than in population-matched nonathletic controls in a small Jamaican cohort, suggesting a similar function in humans. Together, this human and mouse genetic and physiological evidence revealed a critical function of tendons in physical performance, which is tightly and robustly regulated by PIEZO1 in tenocytes.
Collapse
Affiliation(s)
- Ryo Nakamichi
- Department of Molecular Medicine, Scripps Research, 10550 North Torrey Pines Road, MBB-102, La Jolla, CA 92037, USA.,Department of Systems BioMedicine, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-Ku, Tokyo 113-8510, Japan.,Department of Orthopaedic Surgery, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama 700-8558, Japan
| | - Shang Ma
- Howard Hughes Medical Institute, Department of Neuroscience, Dorris Neuroscience Center, Scripps Research, La Jolla, CA, 92037, USA.,Howard Hughes Medical Institute, Chevy Chase, MD 20815-6789, USA
| | - Takayuki Nonoyama
- Faculty of Advanced Life Science and Global Station for Soft Matter, Global Institution for Collaborative Research and Education (GSS, GI-CoRE), Hokkaido University, Sapporo 001-0021, Japan
| | - Tomoki Chiba
- Department of Systems BioMedicine, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-Ku, Tokyo 113-8510, Japan
| | - Ryota Kurimoto
- Department of Systems BioMedicine, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-Ku, Tokyo 113-8510, Japan
| | - Hiroki Ohzono
- Department of Molecular Medicine, Scripps Research, 10550 North Torrey Pines Road, MBB-102, La Jolla, CA 92037, USA
| | - Merissa Olmer
- Department of Molecular Medicine, Scripps Research, 10550 North Torrey Pines Road, MBB-102, La Jolla, CA 92037, USA
| | - Chisa Shukunami
- Department of Molecular Biology and Biochemistry and Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima 734-8553, Japan
| | - Noriyuki Fuku
- Graduate School of Health and Sports Science, Juntendo University, Chiba 270-1965, Japan
| | - Guan Wang
- School of Sport and Health Sciences, University of Brighton, Brighton BN2 4AT, UK.,Centre for Regenerative Medicine and Devices, University of Brighton, Brighton BN2 4AT, UK
| | - Errol Morrison
- National Commission on Science and Technology, PCJ Building, 36 Trafalgar Road, Kingston 10, Jamaica
| | - Yannis P Pitsiladis
- School of Sport and Health Sciences, University of Brighton, Brighton BN2 4AT, UK.,Centre of Stress and Age-related Disease, University of Brighton, Brighton BN2 4AT, UK
| | - Toshifumi Ozaki
- Department of Orthopaedic Surgery, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama 700-8558, Japan
| | - Darryl D'Lima
- Department of Molecular Medicine, Scripps Research, 10550 North Torrey Pines Road, MBB-102, La Jolla, CA 92037, USA
| | - Martin Lotz
- Department of Molecular Medicine, Scripps Research, 10550 North Torrey Pines Road, MBB-102, La Jolla, CA 92037, USA
| | - Ardem Patapoutian
- Howard Hughes Medical Institute, Department of Neuroscience, Dorris Neuroscience Center, Scripps Research, La Jolla, CA, 92037, USA.,Howard Hughes Medical Institute, Chevy Chase, MD 20815-6789, USA
| | - Hiroshi Asahara
- Department of Molecular Medicine, Scripps Research, 10550 North Torrey Pines Road, MBB-102, La Jolla, CA 92037, USA.,Department of Systems BioMedicine, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-Ku, Tokyo 113-8510, Japan
| |
Collapse
|
3
|
Into the Tissues: Extracellular Matrix and Its Artificial Substitutes: Cell Signalling Mechanisms. Cells 2022; 11:cells11050914. [PMID: 35269536 PMCID: PMC8909573 DOI: 10.3390/cells11050914] [Citation(s) in RCA: 34] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 03/02/2022] [Accepted: 03/04/2022] [Indexed: 02/06/2023] Open
Abstract
The existence of orderly structures, such as tissues and organs is made possible by cell adhesion, i.e., the process by which cells attach to neighbouring cells and a supporting substance in the form of the extracellular matrix. The extracellular matrix is a three-dimensional structure composed of collagens, elastin, and various proteoglycans and glycoproteins. It is a storehouse for multiple signalling factors. Cells are informed of their correct connection to the matrix via receptors. Tissue disruption often prevents the natural reconstitution of the matrix. The use of appropriate implants is then required. This review is a compilation of crucial information on the structural and functional features of the extracellular matrix and the complex mechanisms of cell–cell connectivity. The possibilities of regenerating damaged tissues using an artificial matrix substitute are described, detailing the host response to the implant. An important issue is the surface properties of such an implant and the possibilities of their modification.
Collapse
|
4
|
Zhang S, Ju W, Chen X, Zhao Y, Feng L, Yin Z, Chen X. Hierarchical ultrastructure: An overview of what is known about tendons and future perspective for tendon engineering. Bioact Mater 2021; 8:124-139. [PMID: 34541391 PMCID: PMC8424392 DOI: 10.1016/j.bioactmat.2021.06.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 06/07/2021] [Accepted: 06/07/2021] [Indexed: 12/27/2022] Open
Abstract
Abnormal tendons are rarely ever repaired to the natural structure and morphology of normal tendons. To better guide the repair and regeneration of injured tendons through a tissue engineering method, it is necessary to have insights into the internal morphology, organization, and composition of natural tendons. This review summarized recent researches on the structure and function of the extracellular matrix (ECM) components of tendons and highlight the application of multiple detection methodologies concerning the structure of ECMs. In addition, we look forward to the future of multi-dimensional biomaterial design methods and the potential of structural repair for tendon ECM components. In addition, focus is placed on the macro to micro detection methods for tendons, and current techniques for evaluating the extracellular matrix of tendons at the micro level are introduced in detail. Finally, emphasis is given to future extracellular matrix detection methods, as well as to how future efforts could concentrate on fabricating the biomimetic tendons. Summarize recent research on the structure and function of the extracellular matrix (ECM) components of tendons. Comments on current research methods concerning the structure of ECMs. Perspective on the future of multi-dimensional detection techniques and structural repair of tendon ECM components.
Collapse
Affiliation(s)
- Shichen Zhang
- Dr. Li Dak Sum & Yip Yio Chin Center for Stem Cell and Regenerative Medicine and Department of Orthopedic Surgery of the Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, 310052, China.,Key Laboratory of Tissue Engineering and Regenerative Medicine of Zhejiang Province, School of Medicine, Zhejiang University, Hangzhou, 310058, China
| | - Wei Ju
- Key Laboratory of Tissue Engineering and Regenerative Medicine of Zhejiang Province, School of Medicine, Zhejiang University, Hangzhou, 310058, China
| | - Xiaoyi Chen
- Guangxi Key Laboratory of Regenerative Medicine, Guangxi-ASEAN Collaborative Innovation Center for Major Disease Prevention and Treatment, Guangxi Medical University, Guangxi, 530021, China
| | - Yanyan Zhao
- Dr. Li Dak Sum & Yip Yio Chin Center for Stem Cell and Regenerative Medicine and Department of Orthopedic Surgery of the Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, 310052, China.,Key Laboratory of Tissue Engineering and Regenerative Medicine of Zhejiang Province, School of Medicine, Zhejiang University, Hangzhou, 310058, China
| | - Lingchong Feng
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou, 310058, Zhejiang, China
| | - Zi Yin
- Key Laboratory of Tissue Engineering and Regenerative Medicine of Zhejiang Province, School of Medicine, Zhejiang University, Hangzhou, 310058, China.,Dr. Li Dak Sum & Yip Yio Chin Center for Stem Cell and Regenerative Medicine and Regenerative Medicine and Department of Orthopedic Surgery of Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, 310058, China.,Department of Sports Medicine, School of Medicine, Zhejiang University, Hangzhou, 310058, China.,China Orthopedic Regenerative Medicine Group (CORMed), Hangzhou, 310058, China
| | - Xiao Chen
- Dr. Li Dak Sum & Yip Yio Chin Center for Stem Cell and Regenerative Medicine and Department of Orthopedic Surgery of the Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, 310052, China.,Key Laboratory of Tissue Engineering and Regenerative Medicine of Zhejiang Province, School of Medicine, Zhejiang University, Hangzhou, 310058, China.,Guangxi Key Laboratory of Regenerative Medicine, Guangxi-ASEAN Collaborative Innovation Center for Major Disease Prevention and Treatment, Guangxi Medical University, Guangxi, 530021, China.,Department of Sports Medicine, School of Medicine, Zhejiang University, Hangzhou, 310058, China.,China Orthopedic Regenerative Medicine Group (CORMed), Hangzhou, 310058, China
| |
Collapse
|
5
|
Guilak F, Hayes AJ, Melrose J. Perlecan in Pericellular Mechanosensory Cell-Matrix Communication, Extracellular Matrix Stabilisation and Mechanoregulation of Load-Bearing Connective Tissues. Int J Mol Sci 2021; 22:2716. [PMID: 33800241 PMCID: PMC7962540 DOI: 10.3390/ijms22052716] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Revised: 03/04/2021] [Accepted: 03/05/2021] [Indexed: 12/14/2022] Open
Abstract
In this study, we review mechanoregulatory roles for perlecan in load-bearing connective tissues. Perlecan facilitates the co-acervation of tropoelastin and assembly of elastic microfibrils in translamellar cross-bridges which, together with fibrillin and elastin stabilise the extracellular matrix of the intervertebral disc annulus fibrosus. Pericellular perlecan interacts with collagen VI and XI to define and stabilize this matrix compartment which has a strategic position facilitating two-way cell-matrix communication between the cell and its wider extracellular matrix. Cues from the extracellular matrix are fed through this pericellular matrix back to the chondrocyte, allowing it to perceive and respond to subtle microenvironmental changes to regulate tissue homeostasis. Thus perlecan plays a key regulatory role in chondrocyte metabolism, and in chondrocyte differentiation. Perlecan acts as a transport proteoglycan carrying poorly soluble, lipid-modified proteins such as the Wnt or Hedgehog families facilitating the establishment of morphogen gradients that drive tissue morphogenesis. Cell surface perlecan on endothelial cells or osteocytes acts as a flow sensor in blood and the lacunar canalicular fluid providing feedback cues to smooth muscle cells regulating vascular tone and blood pressure, and the regulation of bone metabolism by osteocytes highlighting perlecan's multifaceted roles in load-bearing connective tissues.
Collapse
Affiliation(s)
- Farshid Guilak
- Department of Orthopaedic Surgery, Washington University, St. Louis, MO 63110, USA;
- Shriners Hospitals for Children—St. Louis, St. Louis, MO 63110, USA
| | - Anthony J. Hayes
- Bioimaging Research Hub, Cardiff School of Biosciences, Cardiff University, Cardiff, Wales CF10 3AX, UK;
| | - James Melrose
- Graduate School of Biomedical Engineering, University of New South Wales, Sydney, NSW 2052, Australia
- Raymond Purves Laboratory, Institute of Bone and Joint Research, Kolling Institute, Northern Sydney Local Health District, Royal North Shore Hospital, St. Leonards, NSW 2065, Australia
- Sydney Medical School, Northern, University of Sydney at Royal North Shore Hospital, St. Leonards, NSW 2065, Australia
| |
Collapse
|
6
|
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.
Collapse
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.
| |
Collapse
|
7
|
Hill JR, Eekhoff JD, Brophy RH, Lake SP. Elastic fibers in orthopedics: Form and function in tendons and ligaments, clinical implications, and future directions. J Orthop Res 2020; 38:2305-2317. [PMID: 32293749 PMCID: PMC7572591 DOI: 10.1002/jor.24695] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 03/21/2020] [Accepted: 04/11/2020] [Indexed: 02/04/2023]
Abstract
Elastic fibers are an essential component of the extracellular matrix of connective tissues. The focus of both clinical management and scientific investigation of elastic fiber disorders has centered on the cardiovascular manifestations due to their significant impact on morbidity and mortality. As such, the current understanding of the orthopedic conditions experienced by these patients is limited. The musculoskeletal implications of more subtle elastic fiber abnormalities, whether due to allelic variants or age-related tissue degeneration, are also not well understood. Recent advances have begun to uncover the effects of elastic fiber deficiency on tendon and ligament biomechanics; future research must further elucidate mechanisms governing the role of elastic fibers in these tissues. The identification of population-based genetic variations in elastic fibers will also be essential. Minoxidil administration, modulation of protein expression with micro-RNA molecules, and direct injection of recombinant elastic fiber precursors have demonstrated promise for therapeutic intervention, but further work is required prior to consideration for orthopedic clinical application. This review provides an overview of the role of elastic fibers in musculoskeletal tissue, summarizes current knowledge of the orthopedic manifestations of elastic fiber abnormalities, and identifies opportunities for future investigation and clinical application.
Collapse
Affiliation(s)
- J. Ryan Hill
- Department of Orthopaedic Surgery, Washington University in St. Louis, 425 S. Euclid Avenue, Suite 5505, St. Louis, MO 63110
| | - Jeremy D. Eekhoff
- Department of Biomedical Engineering, Washington University in St. Louis, One Brookings Drive, St. Louis, MO 63130
| | - Robert H. Brophy
- Department of Orthopaedic Surgery, Washington University in St. Louis, 425 S. Euclid Avenue, Suite 5505, St. Louis, MO 63110
| | - Spencer P. Lake
- Department of Biomedical Engineering, Washington University in St. Louis, One Brookings Drive, St. Louis, MO 63130,Department of Mechanical Engineering and Materials Science, Washington University in St. Louis, One Brookings Drive, St. Louis, MO 63130
| |
Collapse
|
8
|
Zamboulis DE, Thorpe CT, Ashraf Kharaz Y, Birch HL, Screen HR, Clegg PD. Postnatal mechanical loading drives adaptation of tissues primarily through modulation of the non-collagenous matrix. eLife 2020; 9:58075. [PMID: 33063662 PMCID: PMC7593091 DOI: 10.7554/elife.58075] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Accepted: 10/12/2020] [Indexed: 02/06/2023] Open
Abstract
Mature connective tissues demonstrate highly specialised properties, remarkably adapted to meet their functional requirements. Tissue adaptation to environmental cues can occur throughout life and poor adaptation commonly results in injury. However, the temporal nature and drivers of functional adaptation remain undefined. Here, we explore functional adaptation and specialisation of mechanically loaded tissues using tendon; a simple aligned biological composite, in which the collagen (fascicle) and surrounding predominantly non-collagenous matrix (interfascicular matrix) can be interrogated independently. Using an equine model of late development, we report the first phase-specific analysis of biomechanical, structural, and compositional changes seen in functional adaptation, demonstrating adaptation occurs postnatally, following mechanical loading, and is almost exclusively localised to the non-collagenous interfascicular matrix. These novel data redefine adaptation in connective tissue, highlighting the fundamental importance of non-collagenous matrix and suggesting that regenerative medicine strategies should change focus from the fibrous to the non-collagenous matrix of tissue.
Collapse
Affiliation(s)
- Danae E Zamboulis
- Institute of Ageing and Chronic Disease, Faculty of Health and Life Sciences, University of Liverpool, Liverpool, United Kingdom
| | - Chavaunne T Thorpe
- Comparative Biomedical Sciences, The Royal Veterinary College, Royal College Street, London, United Kingdom
| | - Yalda Ashraf Kharaz
- Institute of Ageing and Chronic Disease, Faculty of Health and Life Sciences, University of Liverpool, Liverpool, United Kingdom
| | - Helen L Birch
- University College London, Department of Orthopaedics and Musculoskeletal Science, Stanmore Campus, Royal National Orthopaedic Hospital, Stanmore, United Kingdom
| | - Hazel Rc Screen
- Institute of Bioengineering, School of Engineering and Materials Science, Queen Mary University of London, London, United Kingdom
| | - Peter D Clegg
- Institute of Ageing and Chronic Disease, Faculty of Health and Life Sciences, University of Liverpool, Liverpool, United Kingdom
| |
Collapse
|
9
|
Gains CC, Correia JC, Baan GC, Noort W, Screen HRC, Maas H. Force Transmission Between the Gastrocnemius and Soleus Sub-Tendons of the Achilles Tendon in Rat. Front Bioeng Biotechnol 2020; 8:700. [PMID: 32766214 PMCID: PMC7379440 DOI: 10.3389/fbioe.2020.00700] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Accepted: 06/04/2020] [Indexed: 01/19/2023] Open
Abstract
The Achilles tendon (AT) is comprised of three distinct sub-tendons bound together by the inter-subtendon matrix (ISTM). The interactions between sub-tendons will have important implications for AT function. The aim of this study was to investigate the extent to which the ISTM facilitates relative sliding between sub-tendons, and serves as a pathway for force transmission between the gastrocnemius (GAS) and soleus (SOL) sub-tendons of the rat AT. In this study, ATs were harvested from Wistar rats, and the mechanical behavior and composition of the ISTM were explored. To determine force transmission between sub-tendons, the proximal and distal ends of the GAS and SOL sub-tendons were secured, and the forces at each of these locations were measured during proximal loading of the GAS. To determine the ISTM mechanical behavior, only the proximal GAS and distal SOL were secured, and the ISTM was loaded in shear. Finally, for compositional analysis, histological examination assessed the distribution of matrix proteins throughout sub-tendons and the ISTM. The results revealed distinct differences between the forces at the proximal and distal ends of both sub-tendons when proximal loading was applied to the GAS, indicating force transmission between GAS and SOL sub-tendons. Inter-subtendon matrix tests demonstrated an extended initial low stiffness toe region to enable some sub-tendon sliding, coupled with high stiffness linear region such that force transmission between sub-tendons is ensured. Histological data demonstrate an enrichment of collagen III, elastin, lubricin and hyaluronic acid in the ISTM. We conclude that ISTM composition and mechanical behavior are specialized to allow some independent sub-tendon movement, whilst still ensuring capacity for force transmission between the sub-tendons of the AT.
Collapse
Affiliation(s)
- Connor C Gains
- Institute of Bioengineering, School of Engineering and Materials Science, Queen Mary University of London, London, United Kingdom
| | - Janaina C Correia
- Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Amsterdam, Netherlands
| | - Guus C Baan
- Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Amsterdam, Netherlands
| | - Wendy Noort
- Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Amsterdam, Netherlands
| | - Hazel R C Screen
- Institute of Bioengineering, School of Engineering and Materials Science, Queen Mary University of London, London, United Kingdom
| | - Huub Maas
- Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Amsterdam, Netherlands
| |
Collapse
|
10
|
Marr N, Hopkinson M, Hibbert AP, Pitsillides AA, Thorpe CT. Bimodal Whole-Mount Imaging of Tendon Using Confocal Microscopy and X-ray Micro-Computed Tomography. Biol Proced Online 2020; 22:13. [PMID: 32624710 PMCID: PMC7329428 DOI: 10.1186/s12575-020-00126-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Accepted: 06/21/2020] [Indexed: 12/25/2022] Open
Abstract
Background Three-dimensional imaging modalities for optically dense connective tissues such as tendons are limited and typically have a single imaging methodological endpoint. Here, we have developed a bimodal procedure utilising fluorescence-based confocal microscopy and x-ray micro-computed tomography for the imaging of adult tendons to visualise and analyse extracellular sub-structure and cellular composition in small and large animal species. Results Using fluorescent immunolabelling and optical clearing, we visualised the expression of the novel cross-species marker of tendon basement membrane, laminin-α4 in 3D throughout whole rat Achilles tendons and equine superficial digital flexor tendon 5 mm segments. This revealed a complex network of laminin-α4 within the tendon core that predominantly localises to the interfascicular matrix compartment. Furthermore, we implemented a chemical drying process capable of creating contrast densities enabling visualisation and quantification of both fascicular and interfascicular matrix volume and thickness by x-ray micro-computed tomography. We also demonstrated that both modalities can be combined using reverse clarification of fluorescently labelled tissues prior to chemical drying to enable bimodal imaging of a single sample. Conclusions Whole-mount imaging of tendon allowed us to identify the presence of an extensive network of laminin-α4 within tendon, the complexity of which cannot be appreciated using traditional 2D imaging techniques. Creating contrast for x-ray micro-computed tomography imaging of tendon using chemical drying is not only simple and rapid, but also markedly improves on previously published methods. Combining these methods provides the ability to gain spatio-temporal information and quantify tendon substructures to elucidate the relationship between morphology and function.
Collapse
Affiliation(s)
- Neil Marr
- Comparative Biomedical Sciences, Royal Veterinary College, Royal College Street, London, UK
| | - Mark Hopkinson
- Comparative Biomedical Sciences, Royal Veterinary College, Royal College Street, London, UK
| | - Andrew P Hibbert
- Comparative Biomedical Sciences, Royal Veterinary College, Royal College Street, London, UK
| | - Andrew A Pitsillides
- Comparative Biomedical Sciences, Royal Veterinary College, Royal College Street, London, UK
| | - Chavaunne T Thorpe
- Comparative Biomedical Sciences, Royal Veterinary College, Royal College Street, London, UK
| |
Collapse
|
11
|
Hontoir F, Paques F, Simon V, Balau B, Nicaise C, Clegg P, Dugdale A, Vandeweerd JM. Is the T-ligament a ligament? A histological study in equine cadaver forelimbs. Res Vet Sci 2020; 132:10-16. [PMID: 32470846 DOI: 10.1016/j.rvsc.2020.05.018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Revised: 05/17/2020] [Accepted: 05/20/2020] [Indexed: 01/17/2023]
Abstract
Foot pain is a frequent cause of lameness in horses and can involve multiple structures within the hoof. The T-ligament (an anatomical structure connecting the synovium of the distal interphalangeal joint, the digital flexor tendon sheath and the navicular bursa) is poorly described. Five pairs of equine cadaver distal forelimbs were collected from a slaughterhouse. Sagittal sections (medial, middle and lateral) were obtained and processed with Haematoxylin Eosin Safran, Unna's Orcein, and Picrosirius red stains. Histological assessment revealed that the T-ligament was covered by the surrounding synovia of the distal interphalangeal joint, the digital flexor tendon sheath and the navicular bursa. Its collagen content was lower (30.01%±10.15) than that of the collateral sesamoidean ligament (89.48%±5.8; P = .0008) and the middle phalanx (85.72%±3.67; P = .0008). Under polarized light microscopy, it showed a slight heterogeneous pattern of birefringence, with angle-related changes. Elastic fibres were more numerous (21.76%±8.72) than in the collateral sesamoidean ligament (0.28%±0.45), or deep digital flexor tendon (0.04%±0.02); and were more densely packed. Mean cell count was higher for the T-ligament than for other tissues (P = .0007). Blood vessels were identified in the T-ligament and were penetrating the deep digital flexor tendon (8/10 limbs, 5/5 horses). In conclusion, the T-ligament looked like a vinculum for the deep digital flexor tendon, with a central elastic core, surrounding loose connective tissue and blood vessels. It is not a ligament. Its clinical relevance still needs to be determined.
Collapse
Affiliation(s)
- F Hontoir
- NARILIS (Namur Research Institute for Life Sciences), University of Namur, 61 rue de Bruxelles, 5000 Namur, Belgium.
| | - F Paques
- NARILIS (Namur Research Institute for Life Sciences), University of Namur, 61 rue de Bruxelles, 5000 Namur, Belgium
| | - V Simon
- NARILIS (Namur Research Institute for Life Sciences), University of Namur, 61 rue de Bruxelles, 5000 Namur, Belgium
| | - B Balau
- NARILIS (Namur Research Institute for Life Sciences), University of Namur, 61 rue de Bruxelles, 5000 Namur, Belgium
| | - C Nicaise
- NARILIS (Namur Research Institute for Life Sciences), University of Namur, 61 rue de Bruxelles, 5000 Namur, Belgium
| | - P Clegg
- Institute of Ageing and Chronic Diseases, University of Liverpool, William Henry Duncan Building, 6 West Derby Street, Liverpool L7 8TX, United Kingdom
| | - A Dugdale
- ChesterGates Veterinary Specialists CVS (UK) Ltd, Units E & F Telford Court, Gates Lane, Chester CH1 6LT, United Kingdom
| | - J M Vandeweerd
- NARILIS (Namur Research Institute for Life Sciences), University of Namur, 61 rue de Bruxelles, 5000 Namur, Belgium
| |
Collapse
|
12
|
Taye N, Karoulias SZ, Hubmacher D. The "other" 15-40%: The Role of Non-Collagenous Extracellular Matrix Proteins and Minor Collagens in Tendon. J Orthop Res 2020; 38:23-35. [PMID: 31410892 PMCID: PMC6917864 DOI: 10.1002/jor.24440] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Accepted: 08/02/2019] [Indexed: 02/04/2023]
Abstract
Extracellular matrix (ECM) determines the physiological function of all tissues, including musculoskeletal tissues. In tendon, ECM provides overall tissue architecture, which is tailored to match the biomechanical requirements of their physiological function, that is, force transmission from muscle to bone. Tendon ECM also constitutes the microenvironment that allows tendon-resident cells to maintain their phenotype and that transmits biomechanical forces from the macro-level to the micro-level. The structure and function of adult tendons is largely determined by the hierarchical organization of collagen type I fibrils. However, non-collagenous ECM proteins such as small leucine-rich proteoglycans (SLRPs), ADAMTS proteases, and cross-linking enzymes play critical roles in collagen fibrillogenesis and guide the hierarchical bundling of collagen fibrils into tendon fascicles. Other non-collagenous ECM proteins such as the less abundant collagens, fibrillins, or elastin, contribute to tendon formation or determine some of their biomechanical properties. The interfascicular matrix or endotenon and the outer layer of tendons, the epi- and paratenon, includes collagens and non-collagenous ECM proteins, but their function is less well understood. The ECM proteins in the epi- and paratenon may provide the appropriate microenvironment to maintain the identity of distinct tendon cell populations that are thought to play a role during repair processes after injury. The aim of this review is to provide an overview of the role of non-collagenous ECM proteins and less abundant collagens in tendon development and homeostasis. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:23-35, 2020.
Collapse
Affiliation(s)
- Nandaraj Taye
- Leni & Peter W. May Department of Orthopaedics, Orthopaedic Research LaboratoriesIcahn School of Medicine at Mt. SinaiNew York New York 10029
| | - Stylianos Z. Karoulias
- Leni & Peter W. May Department of Orthopaedics, Orthopaedic Research LaboratoriesIcahn School of Medicine at Mt. SinaiNew York New York 10029
| | - Dirk Hubmacher
- Leni & Peter W. May Department of Orthopaedics, Orthopaedic Research LaboratoriesIcahn School of Medicine at Mt. SinaiNew York New York 10029
| |
Collapse
|
13
|
Wu YT, Su WR, Wu PT, Shen PC, Jou IM. Degradation of elastic fiber and elevated elastase expression in long head of biceps tendinopathy. J Orthop Res 2017; 35:1919-1926. [PMID: 27935111 DOI: 10.1002/jor.23500] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Accepted: 11/16/2016] [Indexed: 02/04/2023]
Abstract
Tendinopathy of the long head of the biceps (TLHB) involves various types of extracellular matrix degeneration, but previous studies have not evaluated elastic fibers. The purpose of this study was to investigate elastic fiber distribution in long head of the biceps (LHB). The TLHB tendons of 16 consecutive patients (eight men and eight women; average age of 55.75 years; age range of 40-71 years) were transected and harvested. Three cadaveric LHB tendons were used as the control group. The expression of collagen type I was decreased, but type III was increased in TLHB. Disruption of elastic fibers was particularly observed in grade II specimens where the level of elastase-positive staining was significantly higher than in grade I specimens. Elastic fibers were not observed in the grade III area, implying a higher expression of elastase than in the grade I area. Results of Western blotting showed that the expression of elastin was higher in the control group and the levels of elastin significantly decreased in grades II and III of TLHB. Levels of osteopontin and elastase were increased in primary culture of human tenocytes after experiencing elastic derived peptide treatment. These results suggested that elastase may be caused by the disruption of elastic fibers in the development of chronic tendinopathy and that elastic derived peptide may enhance elastase and osteopontin expression. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:1919-1926, 2017.
Collapse
Affiliation(s)
- Yen-Ting Wu
- Institute of Basic Medical Sciences, National Cheng Kung University, Tainan 70101, Taiwan
| | - Wei-Ren Su
- Department of Orthopaedic Surgery, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan 70428, Taiwan
| | - Po-Ting Wu
- Department of Orthopaedic Surgery, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan 70428, Taiwan
| | - Po-Chuan Shen
- Department of Orthopedic Surgery, Tainan Hospital, Tainan 70101, Taiwan
| | - I-Ming Jou
- Institute of Basic Medical Sciences, National Cheng Kung University, Tainan 70101, Taiwan
- Department of Orthopaedic Surgery, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan 70428, Taiwan
- Department of Orthopedics, E-Da Hospital, Kaohsiung 70824, Taiwan
| |
Collapse
|
14
|
Fang F, Lake SP. Experimental evaluation of multiscale tendon mechanics. J Orthop Res 2017; 35:1353-1365. [PMID: 27878999 DOI: 10.1002/jor.23488] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Accepted: 11/16/2016] [Indexed: 02/04/2023]
Abstract
Tendon's primary function is a mechanical link between muscle and bone. The hierarchical structure of tendon and specific compositional constituents are believed to be critical for proper mechanical function. With increased appreciation for tendon importance and the development of various technological advances, this review paper summarizes recent experimental approaches that have been used to study multiscale tendon mechanics, includes an overview of studies that have evaluated the role of specific tissue constituents, and also proposes challenges/opportunities facing tendon study. Tendon has been demonstrated to have specific structural characteristics (e.g., multi-level hierarchy, crimp pattern, helix) and complex mechanical properties (e.g., non-linearity, anisotropy, viscoelasticity). Physical mechanisms including uncrimping, fiber sliding, and collagen reorganization have been shown to govern tendon mechanical responses under both static and dynamic loading. Several tendon constituents with relatively small quantities have been suggested to play a role in its mechanics, although some results are conflicting. Further research should be performed to understand the interplay and communication of tendon mechanical properties across levels of the hierarchical structure, and further show how each of these components contribute to tendon mechanics. The studies summarized and discussed in this review have helped elucidate important aspects of multiscale tendon mechanics, which is a prerequisite for analyzing stress/strain transfer between multiple scales and identifying key principles of mechanotransduction. This information could further facilitate interpreting the functional diversity of tendons from different species, different locations, and even different developmental stages, and then better understand and identify fundamental concepts related to tendon degeneration, disease, and healing. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:1353-1365, 2017.
Collapse
Affiliation(s)
- Fei Fang
- Department of Mechanical Engineering and Materials Science, Washington University in St. Louis, 1 Brookings Drive, Campus Box 1185, St. Louis, Missouri, 63130
| | - Spencer P Lake
- Department of Mechanical Engineering and Materials Science, Washington University in St. Louis, 1 Brookings Drive, Campus Box 1185, St. Louis, Missouri, 63130.,Department of Biomedical Engineering, Washington University in St. Louis, 1 Brookings Drive, Campus Box 1185, St. Louis, Missouri, 63130.,Department of Orthopaedic Surgery, Washington University in St. Louis, 1 Brookings Drive, Campus Box 1185, St. Louis, Missouri, 63130
| |
Collapse
|
15
|
Pang X, Wu JP, Allison GT, Xu J, Rubenson J, Zheng MH, Lloyd DG, Gardiner B, Wang A, Kirk TB. Three dimensional microstructural network of elastin, collagen, and cells in Achilles tendons. J Orthop Res 2017; 35:1203-1214. [PMID: 27002477 DOI: 10.1002/jor.23240] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 03/17/2016] [Indexed: 02/04/2023]
Abstract
Similar to most biological tissues, the biomechanical, and functional characteristics of the Achilles tendon are closely related to its composition and microstructure. It is commonly reported that type I collagen is the predominant component of tendons and is mainly responsible for the tissue's function. Although elastin has been found in varying proportions in other connective tissues, previous studies report that tendons contain very small quantities of elastin. However, the morphology and the microstructural relationship among the elastic fibres, collagen, and cells in tendon tissue have not been well examined. We hypothesize the elastic fibres, as another fibrillar component in the extracellular matrix, have a unique role in mechanical function and microstructural arrangement in Achilles tendons. It has been shown that elastic fibres present a close connection with the tenocytes. The close relationship of the three components has been revealed as a distinct, integrated and complex microstructural network. Notably, a "spiral" structure within fibril bundles in Achilles tendons was observed in some samples in specialized regions. This study substantiates the hierarchical system of the spatial microstructure of tendon, including the mapping of collagen, elastin and tenocytes, with 3-dimensional confocal images. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:1203-1214, 2017.
Collapse
Affiliation(s)
- Xin Pang
- Department of Mechanical Engineering, 3D Imaging and Bioengineering Laboratory, Curtin University, Bentley, Western Australia 6102, Australia
| | - Jian-Ping Wu
- Department of Mechanical Engineering, 3D Imaging and Bioengineering Laboratory, Curtin University, Bentley, Western Australia 6102, Australia
| | - Garry T Allison
- The School of Physiotherapy and Exercise Sciences, Curtin University, Western Australia, Australia
| | - Jiake Xu
- The School of Pathology and Laboratory Medicine, University of Western Australia, Western Australia, Australia
| | - Jonas Rubenson
- Department of Kinesiology, Pennsylvania State University, Pennsylvania.,School of Sport Science, Exercise and Health, University of Western Australia, Western Australia, Australia
| | - Ming-Hao Zheng
- Centre for Orthopaedic Research, School of Surgery, University of Western Australia, Western Australia, Australia
| | - David G Lloyd
- Centre for Musculoskeletal Research, Menzies Health Institute Queensland, Griffith University, Queensland, Australia
| | - Bruce Gardiner
- School of Engineering and Information Technology, Murdoch University, Western Australia, Australia
| | - Allan Wang
- Centre for Orthopaedic Research, School of Surgery, University of Western Australia, Western Australia, Australia.,St John of God Hospital, Western Australia, Australia
| | - Thomas Brett Kirk
- Department of Mechanical Engineering, 3D Imaging and Bioengineering Laboratory, Curtin University, Bentley, Western Australia 6102, Australia
| |
Collapse
|
16
|
A quantitative label-free analysis of the extracellular proteome of human supraspinatus tendon reveals damage to the pericellular and elastic fibre niches in torn and aged tissue. PLoS One 2017; 12:e0177656. [PMID: 28542244 PMCID: PMC5436668 DOI: 10.1371/journal.pone.0177656] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Accepted: 05/01/2017] [Indexed: 11/24/2022] Open
Abstract
Tears of the human supraspinatus tendon are common and often cause painful and debilitating loss of function. Progressive failure of the tendon leading to structural abnormality and tearing is accompanied by numerous cellular and extra-cellular matrix (ECM) changes in the tendon tissue. This proteomics study aimed to compare torn and aged rotator cuff tissue to young and healthy tissue, and provide the first ECM inventory of human supraspinatus tendon generated using label-free quantitative LC-MS/MS. Employing two digestion protocols (trypsin and elastase), we analysed grain-sized tendon supraspinatus biopsies from older patients with torn tendons and from healthy, young controls. Our findings confirm measurable degradation of collagen fibrils and associated proteins in old and torn tendons, suggesting a significant loss of tissue organisation. A particularly marked reduction of cartilage oligomeric matrix protein (COMP) raises the possibility of using changes in levels of this glycoprotein as a marker of abnormal tissue, as previously suggested in horse models. Surprisingly, and despite using an elastase digestion for validation, elastin was not detected, suggesting that it is not highly abundant in human supraspinatus tendon as previously thought. Finally, we identified marked changes to the elastic fibre, fibrillin-rich niche and the pericellular matrix. Further investigation of these regions may yield other potential biomarkers and help to explain detrimental cellular processes associated with tendon ageing and tendinopathy.
Collapse
|
17
|
Abstract
Tendons among connective tissue, mainly collagen, contain also elastic fibers (EF) made of fibrillin 1, fibrillin 2 and elastin that are broadly distributed in tendons and represent 1-2% of the dried mass of the tendon. Only in the last years, studies on structure and function of EF in tendons have been performed. Aim of this review is to revise data on the organization of EF in tendons, in particular fibrillin structure and function, and on the clinical manifestations associated to alterations of EF in tendons. Indeed, microfibrils may contribute to tendon mechanics; therefore, their alterations may cause joint hypermobility and contractures which have been found to be clinical features in patients with Marfan syndrome (MFS) and Beals syndrome. The two diseases are caused by mutations in genes FBN1 and FBN2 encoding fibrillin 1 and fibrillin 2, respectively.
Collapse
Affiliation(s)
- Betti Giusti
- Department of Experimental and Clinical Medicine, Excellence Centre for Research, Transfer and High Education for the Development of De Novo Therapies (DENOTHE), University of FlorenceFlorence, Italy
- Marfan Syndrome and Related Disorders Regional (Tuscany) Referral Center, Careggi HospitalFlorence, Italy
| | - Guglielmina Pepe
- Department of Experimental and Clinical Medicine, Excellence Centre for Research, Transfer and High Education for the Development of De Novo Therapies (DENOTHE), University of FlorenceFlorence, Italy
- Marfan Syndrome and Related Disorders Regional (Tuscany) Referral Center, Careggi HospitalFlorence, Italy
| |
Collapse
|
18
|
Fang F, Lake SP. Multiscale mechanical integrity of human supraspinatus tendon in shear after elastin depletion. J Mech Behav Biomed Mater 2016; 63:443-455. [PMID: 27472764 DOI: 10.1016/j.jmbbm.2016.06.032] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Revised: 06/27/2016] [Accepted: 06/30/2016] [Indexed: 01/28/2023]
Abstract
Human supraspinatus tendon (SST) exhibits region-specific nonlinear mechanical properties under tension, which have been attributed to its complex multiaxial physiological loading environment. However, the mechanical response and underlying multiscale mechanism regulating SST behavior under other loading scenarios are poorly understood. Furthermore, little is known about the contribution of elastin to tendon mechanics. We hypothesized that (1) SST exhibits region-specific shear mechanical properties, (2) fiber sliding is the predominant mode of local matrix deformation in SST in shear, and (3) elastin helps maintain SST mechanical integrity by facilitating force transfer among collagen fibers. Through the use of biomechanical testing and multiphoton microscopy, we measured the multiscale mechanical behavior of human SST in shear before and after elastase treatment. Three distinct SST regions showed similar stresses and microscale deformation. Collagen fiber reorganization and sliding were physical mechanisms observed as the SST response to shear loading. Measures of microscale deformation were highly variable, likely due to a high degree of extracellular matrix heterogeneity. After elastase treatment, tendon exhibited significantly decreased stresses under shear loading, particularly at low strains. These results show that elastin contributes to tendon mechanics in shear, further complementing our understanding of multiscale tendon structure-function relationships.
Collapse
Affiliation(s)
- Fei Fang
- Department of Mechanical Engineering & Materials Science, Washington University in St. Louis, United States
| | - Spencer P Lake
- Department of Mechanical Engineering & Materials Science, Washington University in St. Louis, United States; Department of Biomedical Engineering, Washington University in St. Louis, United States; Department of Orthopaedic Surgery, Washington University in St. Louis, United States.
| |
Collapse
|
19
|
Smaldone S, Ramirez F. Fibrillin microfibrils in bone physiology. Matrix Biol 2015; 52-54:191-197. [PMID: 26408953 DOI: 10.1016/j.matbio.2015.09.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Revised: 09/18/2015] [Accepted: 09/19/2015] [Indexed: 02/02/2023]
Abstract
The severe skeletal abnormalities associated with Marfan syndrome (MFS) and congenital contractural arachnodactyly (CCA) underscore the notion that fibrillin assemblies (microfibrils and elastic fibers) play a critical role in bone formation and function in spite of representing a low abundance component of skeletal matrices. Studies of MFS and CCA mice have correlated the skeletal phenotypes of these mutant animals with distinct pathophysiological mechanisms that reflect the contextual contribution of fibrillin-1 and -2 scaffolds to TGFβ and BMP signaling during bone patterning, growth and metabolism. Illustrative examples include the unique role of fibrillin-2 in regulating BMP-dependent limb patterning and the distinct impact of the two fibrillin proteins on the commitment and differentiation of marrow mesenchymal stem cells. Collectively, these findings have important implication for our understanding of the pathophysiological mechanisms that drive age- and injury-related processes of bone degeneration.
Collapse
Affiliation(s)
- Silvia Smaldone
- Department of Pharmacology and Systems Therapeutics, Institute for Systems Biomedicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States
| | - Francesco Ramirez
- Department of Pharmacology and Systems Therapeutics, Institute for Systems Biomedicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States.
| |
Collapse
|
20
|
Screen HRC, Berk DE, Kadler KE, Ramirez F, Young MF. Tendon functional extracellular matrix. J Orthop Res 2015; 33:793-9. [PMID: 25640030 PMCID: PMC4507431 DOI: 10.1002/jor.22818] [Citation(s) in RCA: 133] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Accepted: 12/13/2014] [Indexed: 02/06/2023]
Abstract
This article is one of a series, summarizing views expressed at the Orthopaedic Research Society New Frontiers in Tendon Research Conference. This particular article reviews the three workshops held under the "Functional Extracellular Matrix" stream. The workshops focused on the roles of the tendon extracellular matrix, such as performing the mechanical functions of tendon, creating the local cell environment, and providing cellular cues. Tendon is a complex network of matrix and cells, and its biological functions are influenced by widely varying extrinsic and intrinsic factors such as age, nutrition, exercise levels, and biomechanics. Consequently, tendon adapts dynamically during development, aging, and injury. The workshop discussions identified research directions associated with understanding cell-matrix interactions to be of prime importance for developing novel strategies to target tendon healing or repair.
Collapse
Affiliation(s)
- Hazel R C Screen
- Institute of Bioengineering, School of Engineering and Materials Science, Queen Mary University of London, Mile End Road, London, E1 4NS, United Kingdom
| | | | | | | | | |
Collapse
|
21
|
Chen ZH, Jin SH, Wang MY, Jin XL, Lv C, Deng YF, Wang JL. Enhanced NLRP3, caspase-1, and IL- 1β levels in degenerate human intervertebral disc and their association with the grades of disc degeneration. Anat Rec (Hoboken) 2014; 298:720-6. [PMID: 25284686 DOI: 10.1002/ar.23059] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 08/07/2014] [Accepted: 08/21/2014] [Indexed: 12/12/2022]
Abstract
The NACHT, LRR, and PYD domains-containing protein 3 (NLRP3) inflammasome plays an important role in a variety of diseases. However, the role of NLRP3 in the human intervertebral disc (IVD) degeneration remains unknown. In the present study, we assessed the expression levels of the NLRP3 inflammasome and its downstream targets caspase-1 and IL-1β in 45 degenerate and seven nondegenerate IVD samples. The correlation between the degeneration scores and expression levels of NLRP3, caspase-1, and IL-1β were also analyzed. The mRNA expression levels of the three molecules (NLRP3, caspase-1, and IL-1β) were higher in the degenerate IVDs group than the controls (nondegenerate IVDs group). Immunohistochemistry showed that the expression levels of all three molecules were markedly increased in the nucleus pulposus of degenerate IVDs compared with nondegenerate IVDs. There was a positive correlation between the degeneration scores and the expression levels of the NLRP3 inflammasome as well as its downstream targets caspase-1 and IL-1β. The findings suggest that excessive activation of the NLRP3 inflammasome results in overproduction of downstream IL-1β, which participates in the pathogenesis of human IVD degeneration. Therefore, the NLRP3 inflammasome might serve as a potential therapeutic target for the prevention and treatment of IVD degeneration.
Collapse
Affiliation(s)
- Zhong-Hua Chen
- Department of Anesthesiology, Shaoxing People's Hospital and Shaoxing Hospital of Zhejiang University, Shaoxing, People's Republic of China
| | | | | | | | | | | | | |
Collapse
|
22
|
Thakkar D, Grant TM, Hakimi O, Carr AJ. Distribution and expression of type VI collagen and elastic fibers in human rotator cuff tendon tears. Connect Tissue Res 2014; 55:397-402. [PMID: 25166893 DOI: 10.3109/03008207.2014.959119] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
There is increasing evidence for a progressive extracellular matrix change in rotator cuff disease progression. Directly surrounding the cell is the pericellular matrix, where assembly of matrix aggregates typically occurs making it critical in the response of tendon cells to pathological conditions. Studies in animal models have identified type VI collagen, fibrillin-1 and elastin to be located in the pericellular matrix of tendon and contribute in maintaining the structural and biomechanical integrity of tendon. However, there have been no reports on the localization of these proteins in human tendon biopsies. This study aimed to characterize the distribution of these ECM components in human rotator cuffs and gain greater insight into the relationship of pathology to tear size by analyzing the distribution and expression profiles of these ECM components. Confocal microscopy confirmed the localization of these structural molecules in the pericellular matrix of the human rotator cuff. Tendon degeneration led to an increased visibility of these components with a significant disorganization in the distribution of type VI collagen. At the genetic level, an increase in tear size was linked to an increased transcription of type VI collagen and fibrillin-1 with no significant alteration in the elastin levels. This is the first study to confirm the localization of type VI collagen, elastin and fibrillin-1 in the pericellular region of human supraspinatus tendon and assesses the effect of tendon degeneration on these structures, thus providing a useful insight into the composition of human rotator cuff tears which can be instrumental in predicting disease prognosis.
Collapse
Affiliation(s)
- Dipti Thakkar
- Nuffield Department of Orthopedics, Rheumatology and Musculoskeletal Sciences, University of Oxford , Oxford , UK and
| | | | | | | |
Collapse
|
23
|
The urethral rhabdosphincter, levator ani muscle, and perineal membrane: a review. BIOMED RESEARCH INTERNATIONAL 2014; 2014:906921. [PMID: 24877147 PMCID: PMC4022307 DOI: 10.1155/2014/906921] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/26/2013] [Revised: 03/04/2014] [Accepted: 03/05/2014] [Indexed: 01/31/2023]
Abstract
Detailed knowledge of the anatomy of the rhabdosphincter and adjacent tissues is mandatory during urologic surgery to ensure reliable oncologic and functional outcomes. To characterize the levator ani (LA) function for the urethral sphincter, we described connective tissue morphology between the LA and urethral rhabdosphincter. The interface tissue between the LA and rhabdosphincter area in males contained abundant irregularly arrayed elastic fibers and smooth muscles. The male rhabdosphincter was positioned alongside the LA to divide the elevation force and not in-series along the axis of LA contraction. The male perineal membrane was thin but solid and extends along the inferior margin or bottom of the rhabdosphincter area. In contrast, the female rhabdosphincter, including the compressor urethrae and urethrovaginal sphincter muscles, was embedded in the elastic fiber mesh that is continuous with the thick, multilaminar perineal membrane. The inferomedial edge of the female LA was attached to the upper surface of the perineal membrane and not directly attached to the rhabdosphincter. We presented new diagrams showing the gender differences in topographical anatomy of the LA and rhabdosphincter.
Collapse
|
24
|
Sasaki H, Hinata N, Kurokawa T, Murakami G. Supportive tissues of the vagina with special reference to a fibrous skeleton in the perineum: A review. ACTA ACUST UNITED AC 2014. [DOI: 10.4236/ojog.2014.43025] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
25
|
Torricelli P, Veronesi F, Pagani S, Maffulli N, Masiero S, Frizziero A, Fini M. In vitro tenocyte metabolism in aging and oestrogen deficiency. AGE (DORDRECHT, NETHERLANDS) 2013; 35:2125-36. [PMID: 23274854 PMCID: PMC3825001 DOI: 10.1007/s11357-012-9500-0] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2012] [Accepted: 12/05/2012] [Indexed: 05/06/2023]
Abstract
Little is known about tendons and tenocyte biological behaviour during aging and, especially, oestrogen deficiency. The aim of this study was to evaluate in vitro the proliferation and metabolism of tenocytes isolated from the Achilles tendons of ovariectomised (OVX), middle-aged (OLD) and young (YOUNG) rats. An in vitro model of micro-wound healing was also used to assess age and oestrogen deficiency differences in tendon healing. In standard culture condition, OLD and OVX tenocytes showed a significantly lower proliferation rate, collagen I, aggrecan and elastin than YOUNG ones. In OVX group, fibronectin and elastin significantly decreased in comparison to YOUNG and OLD groups, respectively, whereas vascular endothelial growth factor and metalloproteinases-13 increased than those of both YOUNG and OLD groups. In the micro-wound healing model, tenocytes from both OVX and OLD showed a significantly lower healing rate, proliferation rate, collagen I and nitrix oxide in comparison to YOUNG. OVX elastin value was significantly lower than YOUNG one and OVX healing rate and cell migration speed, proliferation rate and fibronectin results were lower, whereas collagen III and metalloproteinase-13 higher in comparison to both YOUNG and OLD groups. These results highlighted how aging and, more significantly, oestrogen deficiency negatively affect tendon metabolism and healing. Our work improves the body of knowledge on the effects of senescence and oestrogen deficiency on tenocyte behaviour and allows further studies to find solution for the prevention of tendon injuries in aging and menopause.
Collapse
Affiliation(s)
- P Torricelli
- Preclinical and Surgical Studies Laboratory, Codivilla Putti Research Institute, Rizzoli Orthopaedic Institute, via di Barbiano, 1/10, 40136, Bologna, Italy,
| | | | | | | | | | | | | |
Collapse
|
26
|
Nishikawa T, Yamamoto T, Honjo KI, Ichioka H, Yamamoto K, Kanamura N, Kato H, Wato M, Kubo T, Mori M, Tanaka A. Marfan's syndrome: Clinical manifestations in the oral-craniofacial area, biophysiological roles of fibrillins and elastic extracellular microfibers, and disease control of the fibrillin gene. JOURNAL OF ORAL AND MAXILLOFACIAL SURGERY MEDICINE AND PATHOLOGY 2013. [DOI: 10.1016/j.ajoms.2013.02.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
|
27
|
Thorpe CT, Birch HL, Clegg PD, Screen HRC. The role of the non-collagenous matrix in tendon function. Int J Exp Pathol 2013; 94:248-59. [PMID: 23718692 DOI: 10.1111/iep.12027] [Citation(s) in RCA: 123] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2013] [Accepted: 04/16/2013] [Indexed: 01/26/2023] Open
Abstract
Tendon consists of highly ordered type I collagen molecules that are grouped together to form subunits of increasing diameter. At each hierarchical level, the type I collagen is interspersed with a predominantly non-collagenous matrix (NCM) (Connect. Tissue Res., 6, 1978, 11). Whilst many studies have investigated the structure, organization and function of the collagenous matrix within tendon, relatively few have studied the non-collagenous components. However, there is a growing body of research suggesting the NCM plays an important role within tendon; adaptations to this matrix may confer the specific properties required by tendons with different functions. Furthermore, age-related alterations to non-collagenous proteins have been identified, which may affect tendon resistance to injury. This review focuses on the NCM within the tensional region of developing and mature tendon, discussing the current knowledge and identifying areas that require further study to fully understand structure-function relationships within tendon. This information will aid in the development of appropriate techniques for tendon injury prevention and treatment.
Collapse
Affiliation(s)
- Chavaunne T Thorpe
- Institute of Bioengineering, School of Engineering and Materials Science, Queen Mary University of London, London E1 4NS, UK.
| | | | | | | |
Collapse
|
28
|
Thompson MS. Tendon mechanobiology: experimental models require mathematical underpinning. Bull Math Biol 2013; 75:1238-54. [PMID: 23681792 DOI: 10.1007/s11538-013-9850-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2012] [Accepted: 04/25/2013] [Indexed: 10/26/2022]
Abstract
Mathematical and computational modeling is in demand to help address current challenges in mechanobiology of musculoskeletal tissues. In particular for tendon, the high clinical importance of the tissue, the huge mechanical demands placed on it and its ability to adapt to these demands, require coupled, multiscale models incorporating complex geometrical and microstructural information as well as time-based descriptions of cellular activity and response.This review introduces the information sources required to develop such multiscale models. It covers tissue structure and biomechanics, cell biomechanics, the current understanding of tendon's ability in health and disease to update its properties and structure and the few already existing multiscale mechanobiological models of the tissue. Finally, a sketch is provided of what such models could achieve ideally, pointing out where experimental data and knowledge are still missing.
Collapse
Affiliation(s)
- Mark S Thompson
- Institute of Biomedical Engineering, Botnar Research Centre, University of Oxford, Windmill Road, Oxford, OX3 7LD, UK.
| |
Collapse
|
29
|
Grant TM, Thompson MS, Urban J, Yu J. Elastic fibres are broadly distributed in tendon and highly localized around tenocytes. J Anat 2013; 222:573-9. [PMID: 23587025 DOI: 10.1111/joa.12048] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/19/2013] [Indexed: 01/23/2023] Open
Abstract
Elastic fibres have the unique ability to withstand large deformations and are found in numerous tissues, but their organization and structure have not been well defined in tendon. The objective of this study was to characterize the organization of elastic fibres in tendon to understand their function. Immunohistochemistry was used to visualize elastic fibres in bovine flexor tendon with fibrillin-1, fibrillin-2 and elastin antibodies. Elastic fibres were broadly distributed throughout tendon, and highly localized longitudinally around groups of cells and transversely between collagen fascicles. The close interaction of elastic fibres and cells suggests that elastic fibres are part of the pericellular matrix and therefore affect the mechanical environment of tenocytes. Fibres present between fascicles are likely part of the endotenon sheath, which enhances sliding between adjacent collagen bundles. These results demonstrate that elastic fibres are highly localized in tendon and may play an important role in cellular function and contribute to the tissue mechanics of the endotenon sheath.
Collapse
Affiliation(s)
- Tyler M Grant
- Department of Engineering, Science, Institute of Biomedical Engineering, University of Oxford, Oxford, UK.
| | | | | | | |
Collapse
|
30
|
Komiyama Y, Ohba S, Shimohata N, Nakajima K, Hojo H, Yano F, Takato T, Docheva D, Shukunami C, Hiraki Y, Chung UI. Tenomodulin expression in the periodontal ligament enhances cellular adhesion. PLoS One 2013; 8:e60203. [PMID: 23593173 PMCID: PMC3622668 DOI: 10.1371/journal.pone.0060203] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Accepted: 02/22/2013] [Indexed: 11/09/2022] Open
Abstract
Tenomodulin (Tnmd) is a type II transmembrane protein characteristically expressed in dense connective tissues such as tendons and ligaments. Its expression in the periodontal ligament (PDL) has also been demonstrated, though the timing and function remain unclear. We investigated the expression of Tnmd during murine tooth eruption and explored its biological functions in vitro. Tnmd expression was related to the time of eruption when occlusal force was transferred to the teeth and surrounding tissues. Tnmd overexpression enhanced cell adhesion in NIH3T3 and human PDL cells. In addition, Tnmd-knockout fibroblasts showed decreased cell adhesion. In the extracellular portions of Tnmd, the BRICHOS domain or CS region was found to be responsible for Tnmd-mediated enhancement of cell adhesion. These results suggest that Tnmd acts on the maturation or maintenance of the PDL by positively regulating cell adhesion via its BRICHOS domain.
Collapse
Affiliation(s)
- Yuske Komiyama
- Department of Sensory and Motor System Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
- Department of Oral and Maxilofacial Surgery, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
- * E-mail: (SO); (YK)
| | - Shinsuke Ohba
- Center for Disease Biology and Integrative Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
- * E-mail: (SO); (YK)
| | - Nobuyuki Shimohata
- Center for Disease Biology and Integrative Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Keiji Nakajima
- Department of Sensory and Motor System Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
- Department of Oral and Maxilofacial Surgery, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Hironori Hojo
- Department of Oral and Maxilofacial Surgery, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
- Center for Disease Biology and Integrative Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Fumiko Yano
- Center for Disease Biology and Integrative Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Tsuyoshi Takato
- Department of Sensory and Motor System Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
- Department of Oral and Maxilofacial Surgery, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Denitsa Docheva
- Laboratory for Experimental Surgery and Regenerative Medicine, Department of Surgery, Ludwig-Maximilians-University, Munich, Germany
| | - Chisa Shukunami
- Department of Cellular Differentiation, Institute for Frontier Medical Sciences, Kyoto University, Kyoto-city, Kyoto, Japan
| | - Yuji Hiraki
- Department of Cellular Differentiation, Institute for Frontier Medical Sciences, Kyoto University, Kyoto-city, Kyoto, Japan
| | - Ung-il Chung
- Center for Disease Biology and Integrative Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| |
Collapse
|
31
|
Kinoshita H, Umezawa T, Omine Y, Kasahara M, Rodríguez-Vázquez JF, Murakami G, Abe S. Distribution of elastic fibers in the head and neck: a histological study using late-stage human fetuses. Anat Cell Biol 2013; 46:39-48. [PMID: 23560235 PMCID: PMC3615611 DOI: 10.5115/acb.2013.46.1.39] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2012] [Revised: 12/01/2012] [Accepted: 12/17/2012] [Indexed: 01/13/2023] Open
Abstract
There is little or no information about the distribution of elastic fibers in the human fetal head. We examined this issue in 15 late-stage fetuses (crown-rump length, 220-320 mm) using aldehyde-fuchsin and elastica-Masson staining, and we used the arterial wall elastic laminae and external ear cartilages as positive staining controls. The posterior pharyngeal wall, as well as the ligaments connecting the laryngeal cartilages, contained abundant elastic fibers. In contrast with the sphenomandibular ligament and the temporomandibular joint disk, in which elastic fibers were partly present, the discomalleolar ligament and the fascial structures around the pterygoid muscles did not have any elastic fibers. In addition, the posterior marginal fascia of the prestyloid space did contain such fibers. Notably, in the middle ear, elastic fibers accumulated along the tendons of the tensor tympani and stapedius muscles and in the joint capsules of the ear ossicle articulations. Elastic fibers were not seen in any other muscle tendons or vertebral facet capsules in the head and neck. Despite being composed of smooth muscle, the orbitalis muscle did not contain any elastic fibers. The elastic fibers in the sphenomandibular ligament seemed to correspond to an intermediate step of development between Meckel's cartilage and the final ligament. Overall, there seemed to be a mini-version of elastic fiber distribution compared to that in adults and a different specific developmental pattern of connective tissues. The latter morphology might be a result of an adaptation to hypoxic conditions during development.
Collapse
|
32
|
Thorpe CT, Udeze CP, Birch HL, Clegg PD, Screen HRC. Specialization of tendon mechanical properties results from interfascicular differences. J R Soc Interface 2012; 9:3108-17. [PMID: 22764132 PMCID: PMC3479922 DOI: 10.1098/rsif.2012.0362] [Citation(s) in RCA: 145] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2012] [Accepted: 06/13/2012] [Indexed: 11/12/2022] Open
Abstract
Tendons transfer force from muscle to bone. Specific tendons, including the equine superficial digital flexor tendon (SDFT), also store and return energy. For efficient function, energy-storing tendons need to be more extensible than positional tendons such as the common digital extensor tendon (CDET), and when tested in vitro have a lower modulus and failure stress, but a higher failure strain. It is not known how differences in matrix organization contribute to distinct mechanical properties in functionally different tendons. We investigated the properties of whole tendons, tendon fascicles and the fascicular interface in the high-strain energy-storing SDFT and low-strain positional CDET. Fascicles failed at lower stresses and strains than tendons. The SDFT was more extensible than the CDET, but SDFT fascicles failed at lower strains than CDET fascicles, resulting in large differences between tendon and fascicle failure strain in the SDFT. At physiological loads, the stiffness at the fascicular interface was lower in the SDFT samples, enabling a greater fascicle sliding that could account for differences in tendon and fascicle failure strain. Sliding between fascicles prior to fascicle extension in the SDFT may allow the large extensions required in energy-storing tendons while protecting fascicles from damage.
Collapse
Affiliation(s)
- Chavaunne T Thorpe
- Medical Engineering Division, School of Engineering and Materials Science, Queen Mary, University of London, Mile End Road, London E1 4NS, UK.
| | | | | | | | | |
Collapse
|
33
|
Hayes AJ, Lord MS, Smith SM, Smith MM, Whitelock JM, Weiss AS, Melrose J. Colocalization in vivo and association in vitro of perlecan and elastin. Histochem Cell Biol 2011; 136:437-54. [PMID: 21874555 DOI: 10.1007/s00418-011-0854-7] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/01/2011] [Indexed: 12/30/2022]
Abstract
We have colocalized elastin and fibrillin-1 with perlecan in extracellular matrix of tensional and weight-bearing connective tissues. Elastin and fibrillin-1 were identified as prominent components of paraspinal blood vessels, and posterior longitudinal ligament in the human fetal spine and outer annulus fibrosus of the fetal intervertebral disc. We also colocalized perlecan with a synovial elastic basal lamina, where the attached synovial cells were observed to produce perlecan. Elastin, fibrillin-1 and perlecan were co-localized in the intima and media of small blood vessels in the synovium and in human fetal paraspinal blood vessels. Elastic fibers were observed at the insertion point of the anterior cruciate ligament to bone in the ovine stifle joint where they colocalized with perlecan. Elastin has not previously been reported to be spatially associated with perlecan in these tissues. Interactions between the tropoelastin and perlecan heparan sulfate chains were demonstrated using quartz crystal microbalance with dissipation solid phase binding studies. Electrostatic interactions through the heparan sulfate chains of perlecan and core protein mediated the interactions with tropoelastin, and were both important in the coacervation of tropoelastin and deposition of elastin onto perlecan immobilized on the chip surface. This may help us to understand the interactions which are expected to occur in vivo between the tropoelastin and perlecan to facilitate the deposition of elastin and formation of elastic microfibrils in situ and would be consistent with the observed distributions of these components in a number of connective tissues.
Collapse
Affiliation(s)
- Anthony J Hayes
- BioImaging Unit, Cardiff School of Biosciences, University of Cardiff, Cardiff, UK
| | | | | | | | | | | | | |
Collapse
|
34
|
Haddad O, Gumez L, Hawse JR, Subramaniam M, Spelsberg TC, Bensamoun SF. TIEG1-null tenocytes display age-dependent differences in their gene expression, adhesion, spreading and proliferation properties. Exp Cell Res 2011; 317:1726-35. [PMID: 21620830 DOI: 10.1016/j.yexcr.2011.05.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2011] [Revised: 05/09/2011] [Accepted: 05/10/2011] [Indexed: 10/18/2022]
Abstract
The remodeling of extracellular matrix is a crucial mechanism in tendon development and the proliferation of fibroblasts is a key factor in this process. The purpose of this study was to further elucidate the role of TIEG1 in mediating important tenocyte properties throughout the aging process. Wildtype and TIEG1 knockout tenocytes adhesion, spreading and proliferation were characterized on different substrates (fibronectin, collagen type I, gelatin and laminin) and the expression levels of various genes known to be involved with tendon development were analyzed by RT-PCR. The experiments revealed age-dependent and substrate-dependent properties for both wildtype and TIEG1 knockout tenocytes. Taken together, our results indicate an important role for TIEG1 in regulating tenocytes adhesion, spreading, and proliferation throughout the aging process. Understanding the basic mechanisms of TIEG1 in tenocytes may provide valuable information for treating multiple tendon disorders.
Collapse
Affiliation(s)
- Oualid Haddad
- Laboratoire de Biomécanique et Bioingénierie UMR CNRS 6600, Université de Technologie de Compiègne, Compiègne, France
| | | | | | | | | | | |
Collapse
|
35
|
Smith KD, Vaughan-Thomas A, Spiller DG, Innes JF, Clegg PD, Comerford EJ. The organisation of elastin and fibrillins 1 and 2 in the cruciate ligament complex. J Anat 2011; 218:600-7. [PMID: 21466551 DOI: 10.1111/j.1469-7580.2011.01374.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Although elastin fibres and oxytalan fibres (bundles of microfibrils) have important mechanical, biochemical and cell regulatory functions, neither their distribution nor their function in cruciate ligaments has been investigated. Twelve pairs of cruciate ligaments (CLs) were obtained from 10 adult dogs with no evidence of knee osteoarthritis. Elastic fibres were identified using Verhoeff's and Miller's staining. Fibrillins 1 and 2 were immunolocalised and imaged using confocal laser scanning microscopy. Hydrated, unfixed tissue was analysed using Nomarski differential interference microscopy (NDIC), allowing structural and mechanical analysis. Microfibrils and elastin fibres were widespread in both CLs, predominantly within ligament fascicles, parallel to collagen bundles. Although elastin fibres were sparse, microfibrils were abundant. We described abundant fibres composed of both fibrillin 1 and fibrillin 2, which had a similar pattern of distribution to oxytalan fibres. NDIC demonstrated complex interfascicular and interbundle anatomy in the CL complex. The distribution of elastin fibres is suggestive of a mechanical role in bundle reorganisation following ligament deformation. The presence and location of fibrillin 2 in oxytalan fibres in ligament differs from the solely fibrillin 1-containing oxytalan fibres previously described in tendon and may demonstrate a fundamental difference between ligament and tendon.
Collapse
Affiliation(s)
- Kinley D Smith
- Department of Musculoskeletal Biology, Institute of Aging and Chronic disease and School of Veterinary Science, Leahurst Campus, University of Liverpool, Liverpool, UK.
| | | | | | | | | | | |
Collapse
|
36
|
Little D, Guilak F, Ruch DS. Ligament-derived matrix stimulates a ligamentous phenotype in human adipose-derived stem cells. Tissue Eng Part A 2010; 16:2307-19. [PMID: 20406104 DOI: 10.1089/ten.tea.2009.0720] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Human adipose stem cells (hASCs) can differentiate into a variety of phenotypes. Native extracellular matrix (e.g., demineralized bone matrix or small intestinal submucosa) can influence the growth and differentiation of stem cells. The hypothesis of this study was that a novel ligament-derived matrix (LDM) would enhance expression of a ligamentous phenotype in hASCs compared to collagen gel alone. LDM prepared using phosphate-buffered saline or 0.1% peracetic acid was mixed with collagen gel (COL) and was evaluated for its ability to induce proliferation, differentiation, and extracellular matrix synthesis in hASCs over 28 days in culture at different seeding densities (0, 0.25 x 10(6), 1 x 10(6), or 2 x 10(6) hASC/mL). Biochemical and gene expression data were analyzed using analysis of variance. Fisher's least significant difference test was used to determine differences between treatments following analysis of variance. hASCs in either LDM or COL demonstrated changes in gene expression consistent with ligament development. hASCs cultured with LDM demonstrated more dsDNA content, sulfated-glycosaminoglycan accumulation, and type I and III collagen synthesis, and released more sulfated-glycosaminoglycan and collagen into the medium compared to hASCs in COL (p <or= 0.05). Increased seeding density increased DNA content incrementally over 28 days in culture for LDM but not COL constructs (p <or= 0.05). These findings suggest that LDM can stimulate a ligament phenotype by hASCs, and may provide a novel scaffold material for ligament engineering applications.
Collapse
Affiliation(s)
- Dianne Little
- Division of Orthopaedic Surgery, Department of Surgery, Duke University Medical Center, Durham, North Carolina 27710, USA
| | | | | |
Collapse
|
37
|
Rapko S, Zhang M, Richards B, Hutto E, Dethlefsen S, Duguay S. Identification of the chondrocyte lineage using microfibril-associated glycoprotein-2, a novel marker that distinguishes chondrocytes from synovial cells. Tissue Eng Part C Methods 2010; 16:1367-75. [PMID: 20345228 DOI: 10.1089/ten.tec.2009.0772] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Methods for the lineage identification of cell or tissue-engineered therapeutics must provide a high degree of performance to confidently distinguish the intended cell type from other lineages that could be present in the finished product. For many applications, these methods also require rapid, high-throughput capability. In this work, methods for the identification of autologous cultured chondrocytes for implantation were investigated. A histological analysis confirmed that fibrous tissue occasionally present in biopsies procured for autologous chondrocyte implantation production comprised synovium. Chondrocyte and synovial cell cultures were then examined using a full transcriptome microarray analysis, which revealed cartilage link protein and microfibril-associated glycoprotein-2 (MAGP2) as the most differentially expressed transcripts between the culture types. Performance characteristics of gene expression assays formed by the analysis of cartilage link protein with normalization to either standard reference genes or to MAGP2 were evaluated. The results demonstrate that the MAGP2-based assay provided superior performance for the purpose of cell culture identification compared to assays using standard reference genes. The selectivity against synovial and heterogeneous samples provided by the novel assay suggests it as an appropriate lineage identification method for cell cultures derived from cartilage.
Collapse
Affiliation(s)
- Stephen Rapko
- Genzyme Biosurgery, Cambridge, Massachusetts 02139, USA.
| | | | | | | | | | | |
Collapse
|
38
|
ENU mutagenesis reveals a novel phenotype of reduced limb strength in mice lacking fibrillin 2. PLoS One 2010; 5:e9137. [PMID: 20161761 PMCID: PMC2817753 DOI: 10.1371/journal.pone.0009137] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2009] [Accepted: 01/25/2010] [Indexed: 01/14/2023] Open
Abstract
Background Fibrillins 1 (FBN1) and 2 (FBN2) are components of microfibrils, microfilaments that are present in many connective tissues, either alone or in association with elastin. Marfan's syndrome and congenital contractural arachnodactyly (CCA) result from dominant mutations in the genes FBN1 and FBN2 respectively. Patients with both conditions often present with specific muscle atrophy or weakness, yet this has not been reported in the mouse models. In the case of Fbn1, this is due to perinatal lethality of the homozygous null mice making measurements of strength difficult. In the case of Fbn2, four different mutant alleles have been described in the mouse and in all cases syndactyly was reported as the defining phenotypic feature of homozygotes. Methodology/Principal Findings As part of a large-scale N-ethyl-N-nitrosourea (ENU) mutagenesis screen, we identified a mouse mutant, Mariusz, which exhibited muscle weakness along with hindlimb syndactyly. We identified an amber nonsense mutation in Fbn2 in this mouse mutant. Examination of a previously characterised Fbn2-null mutant, Fbn2fp, identified a similar muscle weakness phenotype. The two Fbn2 mutant alleles complement each other confirming that the weakness is the result of a lack of Fbn2 activity. Skeletal muscle from mutants proved to be abnormal with higher than average numbers of fibres with centrally placed nuclei, an indicator that there are some regenerating muscle fibres. Physiological tests indicated that the mutant muscle produces significantly less maximal force, possibly as a result of the muscles being relatively smaller in Mariusz mice. Conclusions These findings indicate that Fbn2 is involved in integrity of structures required for strength in limb movement. As human patients with mutations in the fibrillin genes FBN1 and FBN2 often present with muscle weakness and atrophy as a symptom, Fbn2-null mice will be a useful model for examining this aspect of the disease process further.
Collapse
|
39
|
Boregowda R, Paul E, White J, Ritty TM. Bone and soft connective tissue alterations result from loss of fibrillin-2 expression. Matrix Biol 2008; 27:661-6. [PMID: 18838118 DOI: 10.1016/j.matbio.2008.09.579] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2008] [Revised: 09/14/2008] [Accepted: 09/15/2008] [Indexed: 10/21/2022]
Abstract
Fibrillins 1, 2 and 3 make up a family of genes that encode large, cysteine-rich extracellular matrix glycoproteins found in connective tissues, lung, blood vessels and other extensible tissues. Fibrillins 1 and 2 have both overlapping as well as separate distributions in human embryonic and adult tissues. Fibrillin-containing microfibrils are known to modulate morphogenetic events by proper targeting of growth factors to the extracellular matrix. Mutation of the fibrillin-2 gene causes a genetic disorder, congenital contractural arachnodactyly (CCA), that results in flexion contractures. Previously, we have shown a distinct fibrillin-2 distribution in the pericellular matrix of interior tenocytes and later demonstrated a unique fibrillin-2 containing structure that runs along the tendon cell arrays in the canine flexor tendon. We hypothesized that loss of these fibrillin-2 containing structures might affect normal tendon development. To test our hypothesis, connective tissues from mice null for fibrillin-2 gene expression were studied. Murine flexor digitorum longus tendons were evaluated for total collagen content, and the intermolecular collagen cross-links hydroxylysyl and lysyl pyridinoline. The results show decreased collagen cross-links in fibrillin-2 null mice, however total collagen content remained the same when compared to wild type. Bone morphology was studied using micro computed tomography (CT). Fibrillin-2 null mice display a focal area of decreased bone length in the extremities as compared to wild type mice. Together, these results demonstrate a role for fibrillin-2 in bone and soft connective tissue morphological and biochemical processes.
Collapse
Affiliation(s)
- Rajeev Boregowda
- Division of Musculoskeletal Sciences, Department of Orthopedics, H089, Penn State College of Medicine, 500 University Drive, Hershey, PA 17033-0850, United States
| | | | | | | |
Collapse
|
40
|
Wong J, Bennett W, Ferguson MWJ, McGrouther DA. Microscopic and histological examination of the mouse hindpaw digit and flexor tendon arrangement with 3D reconstruction. J Anat 2007; 209:533-45. [PMID: 17005025 PMCID: PMC2100351 DOI: 10.1111/j.1469-7580.2006.00625.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Mice are currently the species of choice for the in vivo study of injury, but few detailed anatomical descriptions have been made of rodent digits, limiting their use for the investigation of intrasynovial tendon healing. In this study a detailed microscopic and histological investigation was performed using C57/BL6 and Tie2 LacZ reporter gene transgenic mice. Serial-sectioned mouse hindpaw digits were characterized using haematoxylin and eosin, Masson's trichrome (collagen), Alcian blue (fibrocartilage), Miller's stain (elastin) and TRITC-phalloidin (cellular cytoskeleton) staining. Digital vasculature was demonstrated using FITC-labelled dextran perfusion studies supplemented with LacZ expression in Tie2 LacZ transgenic mice digits. Imaging of the digit used a combination of brightfield and confocal microscopy with three-dimensional reconstruction. Our findings demonstrated that the mouse hindpaw possesses deep and superficial flexor tendons within a synovial sheath comparable with that found in other mammalian species. The intrasynovial tendons were avascular and had regions of fibrocartilaginous specialization relating to areas of compression. Corresponding vascular networks were demonstrated around the sheath using Tie2 LacZ mice and FITC-perfused hindpaws. Furthermore, there is an area of digit where both deep and superficial tendons reside between two pulleys, similar to zone 2 in the human hand where it would be possible to study intrasynovial tendon injury and adhesion formation. In conclusion, although the dimensions of the mouse digit pose technical challenges for surgical intervention, we have identified a model for the study of flexor tendon injury that will permit future genetic manipulation studies.
Collapse
Affiliation(s)
- Jason Wong
- Faculty of Life Sciences, University of Manchester, UK.
| | | | | | | |
Collapse
|
41
|
Smith LJ, Fazzalari NL. Regional variations in the density and arrangement of elastic fibres in the anulus fibrosus of the human lumbar disc. J Anat 2007; 209:359-67. [PMID: 16928204 PMCID: PMC2100325 DOI: 10.1111/j.1469-7580.2006.00610.x] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Elastic fibres are critical components of the extracellular matrix in dynamic biological structures that undergo extension and recoil. Their presence has been demonstrated in the anulus fibrosus of the human lumbar intervertebral disc; however, a detailed regional analysis of their density and arrangement has not been undertaken, limiting our understanding of their structural and functional roles. In this investigation we have quantitatively described regional variations in elastic fibre density in the anulus fibrosus of the human L3-L4 intervertebral disc using histochemistry and light microscopy. Additionally, a multiplanar comparison of patterns of elastic fibre distribution in the intralamellar and interlamellar zones was undertaken. Novel imaging techniques were developed to facilitate the visualization of elastic fibres otherwise masked by dense surrounding matrix. Elastic fibre density was found to be significantly higher in the lamellae of the posterolateral region of the anulus than the anterolateral, and significantly higher in the outer regions than the inner, suggesting that elastic fibre density in each region of the anulus is commensurate with the magnitude of the tensile deformations experienced in bending and torsion. Elastic fibre arrangments in intralamellar and interlamellar zones were shown to be architecturally distinct, suggesting that they perform multiple functional roles within the anulus matrix structural hierarchy.
Collapse
Affiliation(s)
- Lachlan J Smith
- Bone and Joint Research Laboratory, Division of Tissue Pathology, Institute of Medical and Veterinary Science and Hanson Institute, Adelaide, Australia.
| | | |
Collapse
|
42
|
Abstract
Tendons and ligaments (T/L) are very similar fibrous tissues that respectively connect muscle to bone and bone to bone. They are comprised of fibroblasts that produce large amounts of extra-cellular matrix, resulting in a dense and hypocellular structure. The complex molecular organization of T/L, together with high water content, are responsible for their viscoelastic properties, hence insuring their mechanical function. We will first review recent work on tendon embryology and discuss ligament formation, which has been less documented. We will next summarize our current knowledge of T/L molecular architecture, alterations of which are a major cause for disease. We will finally focus on T/L repair after injury and on genetic diseases responsible for T/L defects.
Collapse
Affiliation(s)
- Samuel Tozer
- Centre National de la Recherche Scientifique (CNRS) UMR7622, Paris, France
| | | |
Collapse
|
43
|
Akhtar S, Davies JR, Caterson B. Ultrastructural immunolocalization of alpha-elastin and keratan sulfate proteoglycan in normal and scoliotic lumbar disc. Spine (Phila Pa 1976) 2005; 30:1762-9. [PMID: 16094279 DOI: 10.1097/01.brs.0000171912.44625.29] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN Comparative ultrastructural study of intervertebral discs from normal subjects and patients with scoliosis. OBJECTIVE To identify ultrastructural relations among keratan sulfate (KS) proteoglycan, alpha-elastin, collagen fibers, and elastic fibers in normal and scoliotic discs. SUMMARY OF BACKGROUND KS proteoglycans, elastic fibers, and collagen fibers play important mechanical roles in the intervertebral disc, but the distributions of KS proteoglycans and elastin in this tissue have received little attention. METHODS Tissues were fixed in 4% paraformaldehyde. Monoclonal antibody 5-D-4 (which recognizes a KS epitope on aggrecan, fibromodulin, and lumican) and polyclonal anti-alpha-elastin were visualized with a 10-nm immunogold-conjugated secondary antibody. RESULTS In a normal disc, a regular pattern of KS labeling occurred around collagen fibers, in the cell cytoplasm, and in the rough endoplasmic reticulum; the nucleus pulposus was more densely labeled for KS than was the anulus fibrosus. In scoliotic disc anulus fibrosus, KS labeling was weak throughout the matrix and pericellularly but abundant in lysosomes and on electron-dense material in degenerate cells. Degenerate collagen fibers in scoliotic tissue bore less KS than did normal fibers. KS labeling of the microfibrillar region of elastic fibers was strong in normal disc but weak in scoliotic disc. Elastin labeling of elastic fibers was weaker in scoliotic than in normal tissue. CONCLUSION KS proteoglycans and elastic fibers are closely associated with the lamellar organization of the collagen fibers in a normal disc. In scoliosis, impaired regulation of collagen fibrillogenesis by lumican or fibromodulin may result in disruption of the lamellar structure.
Collapse
Affiliation(s)
- Saeed Akhtar
- School of Optometry and Vision Sciences, Cardiff University, Cardiff, United Kingdom.
| | | | | |
Collapse
|
44
|
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.
Collapse
Affiliation(s)
- M Benjamin
- School of Biosciences, Cardiff University, Cardiff CF10 3US, United Kingdom
| | | |
Collapse
|
45
|
Ritty TM, Roth R, Heuser JE. Tendon cell array isolation reveals a previously unknown fibrillin-2-containing macromolecular assembly. Structure 2003; 11:1179-88. [PMID: 12962636 DOI: 10.1016/s0969-2126(03)00181-3] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Within tendon, between collagen fascicles, cells are organized in linear arrays surrounded by a specialized environment of extracellular matrix (ECM) proteins that are largely unidentified. Our goal was to identify interfascicular, pericellular ECM components and provide additional resolution to the organization of the pericellular matrix. To this end, we employed a combination of enzymatic digestion, mechanical disruption, and differential sedimentation to demonstrate for the first time that it possible to liberate living linear tendon cell arrays from whole tendon. Here, we identify type VI collagen, versican, and fibrillin-2 as components of the immediate pericellular ECM of linearly arrayed tendon cells. Additionally, a unique fibrillin-2-containing macromolecular assembly is described in detail for the first time. This new structure is unlike any previously described fibrillin-containing macromolecular assembly. Having a largely constant diameter, it runs axially along tendon cell arrays and can exceed 1000 microm in length.
Collapse
Affiliation(s)
- Timothy M Ritty
- Department of Orthopaedic Surgery at Barnes-Jewish Hospital, Washington University School of Medicine, St. Louis, MO 63110, USA.
| | | | | |
Collapse
|