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Cyril D, Giugni A, Bangar SS, Mirzaeipoueinak M, Shrivastav D, Sharabi M, Tipper JL, Tavakoli J. Elastic Fibers in the Intervertebral Disc: From Form to Function and toward Regeneration. Int J Mol Sci 2022; 23:8931. [PMID: 36012198 PMCID: PMC9408956 DOI: 10.3390/ijms23168931] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Revised: 08/05/2022] [Accepted: 08/08/2022] [Indexed: 11/16/2022] Open
Abstract
Despite extensive efforts over the past 40 years, there is still a significant gap in knowledge of the characteristics of elastic fibers in the intervertebral disc (IVD). More studies are required to clarify the potential contribution of elastic fibers to the IVD (healthy and diseased) function and recommend critical areas for future investigations. On the other hand, current IVD in-vitro models are not true reflections of the complex biological IVD tissue and the role of elastic fibers has often been ignored in developing relevant tissue-engineered scaffolds and realistic computational models. This has affected the progress of IVD studies (tissue engineering solutions, biomechanics, fundamental biology) and translation into clinical practice. Motivated by the current gap, the current review paper presents a comprehensive study (from the early 1980s to 2022) that explores the current understanding of structural (multi-scale hierarchy), biological (development and aging, elastin content, and cell-fiber interaction), and biomechanical properties of the IVD elastic fibers, and provides new insights into future investigations in this domain.
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Affiliation(s)
- Divya Cyril
- Centre for Health Technologies, School of Biomedical Engineering, Faculty of Engineering and Information Technology, University of Technology Sydney, Sydney, NSW 2007, Australia
| | - Amelia Giugni
- Centre for Health Technologies, School of Biomedical Engineering, Faculty of Engineering and Information Technology, University of Technology Sydney, Sydney, NSW 2007, Australia
| | - Saie Sunil Bangar
- Faculty of Science, University of Technology Sydney, Sydney, NSW 2007, Australia
| | - Melika Mirzaeipoueinak
- Centre for Health Technologies, School of Biomedical Engineering, Faculty of Engineering and Information Technology, University of Technology Sydney, Sydney, NSW 2007, Australia
| | - Dipika Shrivastav
- Centre for Health Technologies, School of Biomedical Engineering, Faculty of Engineering and Information Technology, University of Technology Sydney, Sydney, NSW 2007, Australia
| | - Mirit Sharabi
- Department of Mechanical Engineering and Mechatronics, Ariel University, Ariel 407000, Israel
| | - Joanne L. Tipper
- Centre for Health Technologies, School of Biomedical Engineering, Faculty of Engineering and Information Technology, University of Technology Sydney, Sydney, NSW 2007, Australia
| | - Javad Tavakoli
- Centre for Health Technologies, School of Biomedical Engineering, Faculty of Engineering and Information Technology, University of Technology Sydney, Sydney, NSW 2007, Australia
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Yakovlev EV, Ovsepyan AL, Smirnov AA, Safronova AA, Starchik DA, Zhivolupov SA, Vasil’ev YL, Dydykin SS. Reproducing Morphological Features Of Intervertebral Disc Using Finite Element Modeling To Predict The Course Of Cervical Spine Dorsopathy. RUSSIAN OPEN MEDICAL JOURNAL 2022. [DOI: 10.15275/rusomj.2022.0118] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Study objective — To evaluate how morphological features of intervertebral disc would affect the outcomes of finite element modeling of axial load in the cervical spine, C3-C5, in order to predict the risk of occurrence and course of dorsopathies. Material and Methods — Three-dimensional models of the cervical spine vertebrae were generated from the computed tomography data of a volunteer (24 years old male without detected pathology of his neck). Intervertebral disc models were developed in two configurations. For each model, we performed a finite element investigation of the stress-strain state with the same loading conditions. The load-displacement curves were compared with the experimental data generated from the results of previously conducted in vitro experiments. Results — The maximum and mean displacement values for the isotropic model were 1.15 mm and 0.73 ± 0.45 mm, respectively. For anisotropic model, maximum and mean displacement values were 0.86 mm and 0.47 ± 0.24 mm, correspondingly. Predicted displacement values for both models matched the experimental data fairly well. Stress profiles of intervertebral discs and stress diagrams of facet joints were calculated. Conclusion — The proposed geometric and constitutive configurations of the intervertebral disc take into account specific morphological features at low computational costs, thereby facilitating the modeling of degenerative disc changes.
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Affiliation(s)
- Evgeny V. Yakovlev
- Admiralty Shipyards Medical Center JSC; University under the Inter-Parliamentary Assembly of the EurAsEC, St. Petersburg, Russia; Moscow State Regional University, Moscow
| | - Artur L. Ovsepyan
- Saint Petersburg Electrotechnical University, St. Petersburg, Russia
| | - Alexander A. Smirnov
- Moscow State Regional University, Moscow, Russia; Saint Petersburg State University, St. Petersburg, Russia
| | - Anna A. Safronova
- Saint Petersburg State University of Aerospace Instrumentation, St. Petersburg, Russia
| | - Dmitry A. Starchik
- I.I. Mechnikov Northwestern State Medical University, St. Petersburg, Russia
| | | | - Yuriy L. Vasil’ev
- I.M. Sechenov First Moscow State Medical University (Sechenov University), Moscow, Russia
| | - Sergey S. Dydykin
- I.M. Sechenov First Moscow State Medical University (Sechenov University), Moscow, Russia
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Gkantsinikoudis N, Kapetanakis S, Magras I, Tsiridis E, Kritis A. Tissue-Engineering of Human Intervertebral Disc: A Concise Review. TISSUE ENGINEERING PART B-REVIEWS 2021; 28:848-860. [PMID: 34409867 DOI: 10.1089/ten.teb.2021.0090] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Intervertebral disc (IVD) represents a structure of crucial structural and functional importance for human spine. Pathology of IVD institutes a frequently encountered condition in current clinical practice. Degenerative Disc Disease (DDD), the principal clinical representative of IVD pathology, constitutes an increasingly diagnosed spinal disorder associated with substantial morbidity and mortality in recent years. Despite the considerable incidence and socioeconomic burden of DDD, existing treatment modalities including conservative and surgical methods have been demonstrated to provide a limited therapeutic effect, being not capable of interrupting or reversing natural progress of underlying disease. These limitations underline the requirement for development of novel, innovative and more effective therapeutic strategies for DDD management. Within this literature framework, compromised IVD replacement with a viable IVD construct manufactured with Tissue-Engineering (TE) methods has been recommended as a promising therapeutic strategy for DDD. Existing preliminary preclinical data demonstrate that proper combination of cells from various sources, different scaffold materials and appropriate signaling molecules renders manufacturing of whole-IVD tissue-engineered constructs a technically feasible process. Aim of this narrative review is to critically summarize current published evidence regarding particular aspects of IVD-TE, primarily emphasizing in providing researchers in this field with practicable knowledge in order to enhance clinical translatability of their research and informing clinical practitioners about the features and capabilities of innovative TE science in the field of IVD-TE.
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Affiliation(s)
- Nikolaos Gkantsinikoudis
- School of Medicine, Faculty of Health Sciences, Aristotle University of Thessaloniki (A.U.Th.), Department of Physiology and Pharmacology , Thessaloniki, Greece.,School of Medicine, Faculty of Health Sciences, Aristotle University of Thessaloniki (A.U.Th), cGMP Regenerative Medicine Facility, Department of Physiology and Pharmacology, Thessaloniki, Greece;
| | - Stylianos Kapetanakis
- Interbalkan European Medical Center, Spine Department and Deformities, Thessaloniki, Greece;
| | - Ioannis Magras
- AHEPA University General Hospital, Aristotle University of Thessaloniki, Department of Neurosurgery, Thessaloniki, Greece;
| | - Eleftherios Tsiridis
- Papageorgiou General Hospital, Aristotle University Medical School, Academic Orthopaedic Department, Thessaloniki Ring Road, Nea Efkarpia, Greece.,Aristotle University Thessaloniki, Balkan Center, Buildings A & B, Center of Orthopaedics and Regenerative Medicine (C.O.RE.), Center of Interdisciplinary Research and Innovation (C.I.R.I.), Thessaloniki, 10th km Thessaloniki-Thermi Rd, Greece;
| | - Aristeidis Kritis
- School of Medicine, Faculty of Health Sciences, Aristotle University of Thessaloniki (A.U.Th.), Department of Physiology and Pharmacology , Thessaloniki, Greece.,School of Medicine, Faculty of Health Sciences, Aristotle University of Thessaloniki (A.U.Th), cGMP Regenerative Medicine Facility, Department of Physiology and Pharmacology, Thessaloniki, Greece;
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Synchrotron tomography of intervertebral disc deformation quantified by digital volume correlation reveals microstructural influence on strain patterns. Acta Biomater 2019; 92:290-304. [PMID: 31082569 DOI: 10.1016/j.actbio.2019.05.021] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Revised: 05/01/2019] [Accepted: 05/07/2019] [Indexed: 11/22/2022]
Abstract
The intervertebral disc (IVD) has a complex and multiscale extracellular matrix structure which provides unique mechanical properties to withstand physiological loading. Low back pain has been linked to degeneration of the disc but reparative treatments are not currently available. Characterising the disc's 3D microstructure and its response in a physiologically relevant loading environment is required to improve understanding of degeneration and to develop new reparative treatments. In this study, techniques for imaging the native IVD, measuring internal deformation and mapping volumetric strain were applied to an in situ compressed ex vivo rat lumbar spine segment. Synchrotron X-ray micro-tomography (synchrotron CT) was used to resolve IVD structures at microscale resolution. These image data enabled 3D quantification of collagen bundle orientation and measurement of local displacement in the annulus fibrosus between sequential scans using digital volume correlation (DVC). The volumetric strain mapped from synchrotron CT provided a detailed insight into the micromechanics of native IVD tissue. The DVC findings showed that there was no slipping at lamella boundaries, and local strain patterns were of a similar distribution to the previously reported elastic network with some heterogeneous areas and maximum strain direction aligned with bundle orientation, suggesting bundle stretching and sliding. This method has the potential to bridge the gap between measures of macro-mechanical properties and the local 3D micro-mechanical environment experienced by cells. This is the first evaluation of strain at the micro scale level in the intact IVD and provides a quantitative framework for future IVD degeneration mechanics studies and testing of tissue engineered IVD replacements. STATEMENT OF SIGNIFICANCE: Synchrotron in-line phase contrast X-ray tomography provided the first visualisation of native intact intervertebral disc microstructural deformation in 3D. For two annulus fibrosus volumes of interest, collagen bundle orientation was quantified and local displacement mapped as strain. Direct evidence of microstructural influence on strain patterns could be seen such as no slipping at lamellae boundaries and maximum strain direction aligned with collagen bundle orientation. Although disc elastic structures were not directly observed, the strain patterns had a similar distribution to the previously reported elastic network. This study presents technical advances and is a basis for future X-ray microscopy, structural quantification and digital volume correlation strain analysis of soft tissue.
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Sharabi M, Levi-Sasson A, Wolfson R, Wade KR, Galbusera F, Benayahu D, Wilke HJ, Haj-Ali R. The Mechanical Role of the Radial Fiber Network Within the Annulus Fibrosus of the Lumbar Intervertebral Disc: A Finite Elements Study. J Biomech Eng 2018; 141:2709746. [DOI: 10.1115/1.4041769] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2018] [Indexed: 11/08/2022]
Abstract
The annulus fibrosus (AF) of the intervertebral disc (IVD) consists of a set of concentric layers composed of a primary circumferential collagen fibers arranged in an alternating oblique orientation. Moreover, there exists an additional secondary set of radial translamellar collagen fibers which connects the concentric layers, creating an interconnected fiber network. The aim of this study was to investigate the mechanical role of the radial fiber network. Toward that goal, a three-dimensional (3D) finite element model of the L3–L4 spinal segment was generated and calibrated to axial compression and pure moment loading. The AF model explicitly recognizes the two heterogeneous networks of fibers. The presence of radial fibers demonstrated a pronounced effect on the local disc responses under lateral bending, flexion, and extension modes. In these modes, the radial fibers were in a tensile state in the disc region that subjected to compression. In addition, the circumferential fibers, on the opposite side of the IVD, were also under tension. The local stress in the matrix was decreased in up to 9% in the radial fibers presence. This implies an active fiber network acting collectively to reduce the stresses and strains in the AF lamellae. Moreover, a reduction of 26.6% in the matrix sideways expansion was seen in the presence of the radial fibers near the neutral bending axis of the disc. The proposed biomechanical model provided a new insight into the mechanical role of the radial collagen fibers in the AF structure. This model can assist in the design of future IVD substitutes.
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Affiliation(s)
- Mirit Sharabi
- The Fleischman Faculty of Engineering, School of Mechanical Engineering, Tel Aviv University, Tel Aviv 69978, Israel
| | - Aviad Levi-Sasson
- The Fleischman Faculty of Engineering, School of Mechanical Engineering, Tel Aviv University, Tel Aviv 69978, Israel
| | - Roza Wolfson
- The Fleischman Faculty of Engineering, School of Mechanical Engineering, Tel Aviv University, Tel Aviv 69978, Israel
| | - Kelly R. Wade
- Institute of Orthopaedic Research and Biomechanics, University of Ulm, Ulm 89081, Germany
| | - Fabio Galbusera
- Institute of Orthopaedic Research and Biomechanics, University of Ulm, Ulm 89081, Germany
- IRCCS Galeazzi Orthopaedic Institute, Milan 20161, Italy
| | - Dafna Benayahu
- Department of Cell and Developmental Biology, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Hans-Joachim Wilke
- Institute of Orthopaedic Research and Biomechanics, University of Ulm, Ulm 89081, Germany
| | - Rami Haj-Ali
- Professor The Fleischman Faculty of Engineering, School of Mechanical Engineering, Tel Aviv University, Tel Aviv 69978, Israel e-mail:
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Three-dimensional microstructural reconstruction of the ovine intervertebral disc using ultrahigh field MRI. Spine J 2018; 18:2119-2127. [PMID: 29969731 DOI: 10.1016/j.spinee.2018.06.356] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Revised: 06/22/2018] [Accepted: 06/22/2018] [Indexed: 02/03/2023]
Abstract
BACKGROUND The intervertebral disc (IVD) is a complex organ that acts as a flexible coupling between two adjacent vertebral bodies and must therefore accommodate compression, bending, and torsion. It consists of three main components, which are elegantly structured to allow this: the annulus fibrosus (AF), the nucleus pulposus (NP), and the end-plates (EP). PURPOSE Thus far, it has not been possible to examine the microarchitecture of the disc directly in three dimensions in its unaltered state and thus knowledge of the overall architecture of the disc has been inferred from a range of imaging sources, or by using destructive methods. STUDY DESIGN A nondestructive ultrahigh field Magnetic Resonance Imaging (MRI) of 11.7 T was used together with image analysis to visualize the ovine IVDs. METHODS Three-dimensional image stacks from eight IVDs harvested from sheep, half of which were 4 to 5 years old and the others approximately 2 years old were reconstructed and examined, and their microstructure were imaged. The overall structure of the disc, including the average of 14 AF lamellae (9-28), NP, and EP was then visualized with particular attention given to integrating elements as radial translamellar cross-links, AF-NP transition zone EP-AF integration and EP-NP insertion nodes (ie the connecting junctions between the EP and NP). Moreover, collagen fiber orientation was determined at different depths and locations throughout the annulus. RESULTS It was found that there was a clearer demarcation in the AF-NP transition zone of the younger discs compared with the older ones. This difference was reflected in the visibility of AF-NP and EP-AF integration. It was also possible to view the fiber architecture of the AF-NP integration in greater depth than was possible previously with histological techniques. These fibers were mainly observed in the younger discs and their length was measured to be of 2.6 ± 0.2 mm. CONCLUSIONS The present results provide a substantial advance in visualization of the three-dimensional architecture of an intact IVD and the integration of its components.
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7
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Torre OM, Mroz V, Bartelstein MK, Huang AH, Iatridis JC. Annulus fibrosus cell phenotypes in homeostasis and injury: implications for regenerative strategies. Ann N Y Acad Sci 2018; 1442:61-78. [PMID: 30604562 DOI: 10.1111/nyas.13964] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 08/05/2018] [Accepted: 08/15/2018] [Indexed: 12/11/2022]
Abstract
Despite considerable efforts to develop cellular, molecular, and structural repair strategies and restore intervertebral disk function after injury, the basic biology underlying intervertebral disk healing remains poorly understood. Remarkably, little is known about the origins of cell populations residing within the annulus fibrosus, or their phenotypes, heterogeneity, and roles during healing. This review focuses on recent literature highlighting the intrinsic and extrinsic cell types of the annulus fibrosus in the context of the injury and healing environment. Spatial, morphological, functional, and transcriptional signatures of annulus fibrosus cells are reviewed, including inner and outer annulus fibrosus cells, which we propose to be referred to as annulocytes. The annulus also contains peripheral cells, interlamellar cells, and potential resident stem/progenitor cells, as well as macrophages, T lymphocytes, and mast cells following injury. Phases of annulus fibrosus healing include inflammation and recruitment of immune cells, cell proliferation, granulation tissue formation, and matrix remodeling. However, annulus fibrosus healing commonly involves limited remodeling, with granulation tissues remaining, and the development of chronic inflammatory states. Identifying annulus fibrosus cell phenotypes during health, injury, and degeneration will inform reparative regeneration strategies aimed at improving annulus fibrosus healing.
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Affiliation(s)
- Olivia M Torre
- Leni and Peter W. May Department of Orthopaedics, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Victoria Mroz
- Leni and Peter W. May Department of Orthopaedics, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Meredith K Bartelstein
- Leni and Peter W. May Department of Orthopaedics, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Alice H Huang
- Leni and Peter W. May Department of Orthopaedics, Icahn School of Medicine at Mount Sinai, New York, New York
| | - James C Iatridis
- Leni and Peter W. May Department of Orthopaedics, Icahn School of Medicine at Mount Sinai, New York, New York
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8
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Chu G, Shi C, Wang H, Zhang W, Yang H, Li B. Strategies for Annulus Fibrosus Regeneration: From Biological Therapies to Tissue Engineering. Front Bioeng Biotechnol 2018; 6:90. [PMID: 30042942 PMCID: PMC6048238 DOI: 10.3389/fbioe.2018.00090] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Accepted: 06/18/2018] [Indexed: 12/17/2022] Open
Abstract
Intervertebral disc (IVD) is an avascular tissue which contributes to the weight bearing, motion, and flexibility of spine. However, IVD is susceptible to damage and even failure due to injury, pathology, and aging. Annulus fibrosus (AF), the structural and functional integrity of which is critically essential to confine nucleus pulpous (NP) and maintain physiological intradiscal pressure under mechanical loading, plays a critical role in the biomechanical properties of IVD. AF degeneration commonly results in substantial deterioration of IVD. During this process, the biomechanical properties of AF and the balance between anabolism and catabolism in IVD are progressively disrupted, leading to chronic back pain, and even disability of individuals. Therefore, repairing and regenerating AF are effective treatments to degeneration-associated pains. However, they remain highly challenging due to the complexity of natural AF tissue in the aspects of cell phenotype, biochemical composition, microstructure, and mechanical properties. Tissue engineering (TE), by combining biological science and materials engineering, shed lights on AF regeneration. In this article, we review recent advances in the pro-anabolic approaches in the form of cell delivery, bioactive factors delivery, gene therapy, and TE strategies for achieving AF regeneration.
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Affiliation(s)
- Genglei Chu
- Orthopaedic Institute, Medical College, Soochow University, Suzhou, Jiangsu, China
- Department of Orthopaedic Surgery, First Affiliated Hospital, Soochow University, Suzhou, China
| | - Chen Shi
- Department of Biomedical Engineering, National University of Singapore, Singapore, Singapore
| | - Huan Wang
- Orthopaedic Institute, Medical College, Soochow University, Suzhou, Jiangsu, China
- Department of Orthopaedic Surgery, First Affiliated Hospital, Soochow University, Suzhou, China
| | - Weidong Zhang
- Orthopaedic Institute, Medical College, Soochow University, Suzhou, Jiangsu, China
- Department of Orthopaedic Surgery, First Affiliated Hospital, Soochow University, Suzhou, China
| | - Huilin Yang
- Orthopaedic Institute, Medical College, Soochow University, Suzhou, Jiangsu, China
- Department of Orthopaedic Surgery, First Affiliated Hospital, Soochow University, Suzhou, China
| | - Bin Li
- Orthopaedic Institute, Medical College, Soochow University, Suzhou, Jiangsu, China
- Department of Orthopaedic Surgery, First Affiliated Hospital, Soochow University, Suzhou, China
- China Orthopaedic Regenerative Medicine Group, Hangzhou, China
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9
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Abstract
Mechanical loading of the intervertebral disc (IVD) initiates cell-mediated remodeling events that contribute to disc degeneration. Cells of the IVD, nucleus pulposus (NP) and anulus fibrosus (AF), will exhibit various responses to different mechanical stimuli which appear to be highly dependent on loading type, magnitude, duration, and anatomic zone of cell origin. Cells of the NP, the innermost region of the disc, exhibit an anabolic response to low-moderate magnitudes of static compression, osmotic pressure, or hydrostatic pressure, while higher magnitudes promote a catabolic response marked by increased protease expression and activity. Cells of the outer AF are responsive to physical forces in a manner that depends on frequency and magnitude, as are cells of the NP, though they experience different forces, deformations, pressure, and osmotic pressure in vivo. Much remains to be understood of the mechanotransduction pathways that regulate IVD cell responses to loading, including responses to specific stimuli and also differences among cell types. There is evidence that cytoskeletal remodeling and receptor-mediated signaling are important mechanotransduction events that can regulate downstream effects like gene expression and posttranslational biosynthesis, all of which may influence phenotype and bioactivity. These and other mechanotransduction events will be regulated by known and to-be-discovered cell-matrix and cell-cell interactions, and depend on composition of extracellular matrix ligands for cell interaction, matrix stiffness, and the phenotype of the cells themselves. Here, we present a review of the current knowledge of the role of mechanical stimuli and the impact upon the cellular response to loading and changes that occur with aging and degeneration of the IVD.
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Affiliation(s)
- Bailey V Fearing
- Department of Biomedical Engineering & Orthopedic Surgery, Washington University in St. Louis, St. Louis, Missouri
| | - Paula A Hernandez
- Department of Orthopaedic Surgery, University of Texas Southwestern, Dallas, Texas
| | - Lori A Setton
- Department of Biomedical Engineering & Orthopedic Surgery, Washington University in St. Louis, St. Louis, Missouri
| | - Nadeen O Chahine
- Department of Orthopedic Surgery & Biomedical Engineering, Columbia University, New York, New York
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10
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Disney CM, Lee PD, Hoyland JA, Sherratt MJ, Bay BK. A review of techniques for visualising soft tissue microstructure deformation and quantifying strain Ex Vivo. J Microsc 2018; 272:165-179. [PMID: 29655273 DOI: 10.1111/jmi.12701] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Revised: 03/08/2018] [Accepted: 03/16/2018] [Indexed: 12/16/2022]
Abstract
Many biological tissues have a complex hierarchical structure allowing them to function under demanding physiological loading conditions. Structural changes caused by ageing or disease can lead to loss of mechanical function. Therefore, it is necessary to characterise tissue structure to understand normal tissue function and the progression of disease. Ideally intact native tissues should be imaged in 3D and under physiological loading conditions. The current published in situ imaging methodologies demonstrate a compromise between imaging limitations and maintaining the samples native mechanical function. This review gives an overview of in situ imaging techniques used to visualise microstructural deformation of soft tissue, including three case studies of different tissues (tendon, intervertebral disc and artery). Some of the imaging techniques restricted analysis to observational mechanics or discrete strain measurement from invasive markers. Full-field local surface strain measurement has been achieved using digital image correlation. Volumetric strain fields have successfully been quantified from in situ X-ray microtomography (micro-CT) studies of bone using digital volume correlation but not in soft tissue due to low X-ray transmission contrast. With the latest developments in micro-CT showing in-line phase contrast capability to resolve native soft tissue microstructure, there is potential for future soft tissue mechanics research where 3D local strain can be quantified. These methods will provide information on the local 3D micromechanical environment experienced by cells in healthy, aged and diseased tissues. It is hoped that future applications of in situ imaging techniques will impact positively on the design and testing of potential tissue replacements or regenerative therapies. LAY DESCRIPTION: The soft tissues in our bodies, such as tendons, intervertebral discs and arteries, have evolved to have complicated structures which deform and bear load during normal function. Small changes in these structures can occur with age and disease which then leads to loss of function. Therefore, it is important to image tissue microstructure in 3D and under functional conditions. This paper gives an overview of imaging techniques used to record the deformation of soft tissue microstructures. Commonly there are compromises between obtaining the best imaging result and retaining the samples native structure and function. For example, invasive markers and dissecting samples damages the tissues natural structure, and staining or clearing (making the tissue more transparent) can distort tissue structure. Structural deformation has been quantified from 2D imaging techniques (digital image correlation) to create surface strain maps which help identify local tissue mechanics. When extended to 3D (digital volume correlation), deformation measurement has been limited to bone samples using X-ray micro-CT. Recently it has been possible to image the 3D structure of soft tissue using X-ray micro-CT meaning that there is potential for internal soft tissue mechanics to be mapped in 3D. Future application of micro-CT and digital volume correlation will be important for soft tissue mechanics studies particularly to understand normal function, progression of disease and in the design of tissue replacements.
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Affiliation(s)
- C M Disney
- Centre for Doctoral Training in Regenerative Medicine, University of Manchester, Manchester, U.K.,Division of Cell Matrix Biology and Regenerative Medicine, University of Manchester, Manchester, U.K
| | - P D Lee
- School of Materials, University of Manchester, Manchester, U.K
| | - J A Hoyland
- Division of Cell Matrix Biology and Regenerative Medicine, University of Manchester, Manchester, U.K.,NIHR Manchester Biomedical Research Centre, Manchester Academic Health Science Centre, Central Manchester University Hospitals NHS Foundation Trust, Manchester, U.K
| | - M J Sherratt
- Division of Cell Matrix Biology and Regenerative Medicine, University of Manchester, Manchester, U.K
| | - B K Bay
- School of Mechanical, Industrial and Manufacturing Engineering, Oregon State University, Corvallis, Oregon, U.S.A
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11
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Abstract
STUDY DESIGN Microstructural investigation of low frequency cyclic loading and flexing of the lumbar disc. OBJECTIVE To explore micro-level structural damage in motion segments subjected to low frequency repetitive loading and flexing at sub-acute loads. SUMMARY OF BACKGROUND DATA Cumulative exposure to mechanical load has been implicated in low back pain and injury. The mechanical pathways by which cyclic loading physically affects spine tissues remain unclear, in part due to the absence of high quality microstructural evidence. METHODS The study utilized seven intact ovine lumbar spines and from each spine one motion segment was used as a control, two others were cyclically loaded. Ten motion segments were subjected to 5000 cycles at 0.5 Hz with a peak load corresponding to ∼30% of that required to achieve failure. An additional small group of segments subjected to 10,000 or 30,000 cycles was similarly analyzed. Following chemical fixation and decalcification samples were cryosectioned along one of the oblique fiber angles and imaged in their fully hydrated state using differential interference contrast optical microscopy. Structural damage obtained from the images was organized into an algebraic shell for analysis. RESULTS At 5000 cycles the disc damage was limited to inner wall distortions, evidence of stress concentrations at bridging-lamellae attachments, and small delaminations. The high-cycle discs tested exhibited significant mid-wall damage. There was no evidence of nuclear material being displaced. CONCLUSION At this low frequency and without the application of sustained loading or a more severe loading regime, or maintaining a constant flexion with repetitive loading, it seems unlikely that actual nuclear migration occurs. It is possible that the inner-annular damage shown in the low dose group could disrupt pathways for nutrient diffusion leading to earlier cell death and matrix degradation, thus contributing to a cascade of degeneration. LEVEL OF EVIDENCE N/A.
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12
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Sung B, Kim MH. Liquid-crystalline nanoarchitectures for tissue engineering. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2018; 9:205-215. [PMID: 29441265 PMCID: PMC5789436 DOI: 10.3762/bjnano.9.22] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Accepted: 11/21/2017] [Indexed: 05/03/2023]
Abstract
Hierarchical orders are found throughout all levels of biosystems, from simple biopolymers, subcellular organelles, single cells, and macroscopic tissues to bulky organs. Especially, biological tissues and cells have long been known to exhibit liquid crystal (LC) orders or their structural analogues. Inspired by those native architectures, there has recently been increased interest in research for engineering nanobiomaterials by incorporating LC templates and scaffolds. In this review, we introduce and correlate diverse LC nanoarchitectures with their biological functionalities, in the context of tissue engineering applications. In particular, the tissue-mimicking LC materials with different LC phases and the regenerative potential of hard and soft tissues are summarized. In addition, the multifaceted aspects of LC architectures for developing tissue-engineered products are envisaged. Lastly, a perspective on the opportunities and challenges for applying LC nanoarchitectures in tissue engineering fields is discussed.
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Affiliation(s)
- Baeckkyoung Sung
- Liquid Crystal Institute and Chemical Physics Interdisciplinary Program, Kent State University, Kent, OH 44242, USA
- Department of Biological Sciences, Kent State University, Kent, OH 44242, USA
| | - Min-Ho Kim
- Department of Biological Sciences, Kent State University, Kent, OH 44242, USA
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13
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Disney CM, Madi K, Bodey AJ, Lee PD, Hoyland JA, Sherratt MJ. Visualising the 3D microstructure of stained and native intervertebral discs using X-ray microtomography. Sci Rep 2017; 7:16279. [PMID: 29176563 PMCID: PMC5701246 DOI: 10.1038/s41598-017-16354-w] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 11/10/2017] [Indexed: 01/31/2023] Open
Abstract
Intervertebral disc degeneration (IVDD) is linked to low back pain. Microstructural changes during degeneration have previously been imaged using 2D sectioning techniques and 3D methods which are limited to small specimens and prone to inducing artefacts from sample preparation. This study explores micro computed X-ray tomography (microCT) methods with the aim of resolving IVD 3D microstructure whilst minimising sample preparation artefacts. Low X-ray absorption contrast in non-mineralised tissue can be enhanced using staining and phase contrast techniques. A step-wise approach, including comparing three stains, was used to develop microCT for bovine tail IVD using laboratory and synchrotron sources. Staining successfully contrasted collagenous structures; however not all regions were stained and the procedure induced macroscopic structural changes. Phase contrast microCT of chemically fixed yet unstained samples resolved the nucleus pulposus, annulus fibrosus and constituent lamellae, and finer structures including collagen bundles and cross-bridges. Using the same imaging methods native tissue scans were of slightly lower contrast but free from sample processing artefacts. In the future these methods may be used to characterise structural remodelling in soft (non-calcified) tissues and to conduct in situ studies of native loaded tissues and constructs to characterise their 3D mechanical properties.
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Affiliation(s)
- C M Disney
- Centre for Doctoral Training in Regenerative Medicine, University of Manchester, Manchester, UK.,Division of Cell Matrix Biology and Regenerative Medicine, University of Manchester, Manchester, UK
| | - K Madi
- School of Materials, University of Manchester, Manchester, UK
| | - A J Bodey
- Diamond Light Source, Harwell Science and Innovation Campus, Oxfordshire, UK
| | - P D Lee
- School of Materials, University of Manchester, Manchester, UK
| | - J A Hoyland
- Division of Cell Matrix Biology and Regenerative Medicine, University of Manchester, Manchester, UK.,NIHR Manchester Biomedical Research Centre, Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, UK
| | - M J Sherratt
- Division of Cell Matrix Biology and Regenerative Medicine, University of Manchester, Manchester, UK.
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14
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Ghannam M, Jumah F, Mansour S, Samara A, Alkhdour S, Alzuabi MA, Aker L, Adeeb N, Massengale J, Oskouian RJ, Tubbs RS. Surgical anatomy, radiological features, and molecular biology of the lumbar intervertebral discs. Clin Anat 2017; 30:251-266. [PMID: 27997062 DOI: 10.1002/ca.22822] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Accepted: 12/04/2016] [Indexed: 01/07/2023]
Abstract
The intervertebral disc (IVD) is a joint unique in structure and functions. Lying between adjacent vertebrae, it provides both the primary support and the elasticity required for the spine to move stably. Various aspects of the IVD have long been studied by researchers seeking a better understanding of its dynamics, aging, and subsequent disorders. In this article, we review the surgical anatomy, imaging modalities, and molecular biology of the lumbar IVD. Clin. Anat. 30:251-266, 2017. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Malik Ghannam
- An-Najah National University Hospital, Nablus, Palestine
| | - Fareed Jumah
- An-Najah National University Hospital, Nablus, Palestine
| | - Shaden Mansour
- An-Najah National University Hospital, Nablus, Palestine
| | - Amjad Samara
- An-Najah National University Hospital, Nablus, Palestine
| | - Saja Alkhdour
- An-Najah National University Hospital, Nablus, Palestine
| | | | - Loai Aker
- An-Najah National University Hospital, Nablus, Palestine
| | - Nimer Adeeb
- Department of Neurosurgery, Boston Medical Center, Boston University, Massachusetts
| | - Justin Massengale
- Department of Neurosurgery, Boston Medical Center, Boston University, Massachusetts
| | | | - R Shane Tubbs
- Department of Anatomical Sciences, St. George's University, Grenada.,Seattle Science Foundation, Seattle, Washington
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15
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Ghazanfari S, Khademhosseini A, Smit TH. Mechanisms of lamellar collagen formation in connective tissues. Biomaterials 2016; 97:74-84. [DOI: 10.1016/j.biomaterials.2016.04.028] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Revised: 03/29/2016] [Accepted: 04/20/2016] [Indexed: 12/16/2022]
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16
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Tavakoli J, Elliott DM, Costi JJ. Structure and mechanical function of the inter-lamellar matrix of the annulus fibrosus in the disc. J Orthop Res 2016; 34:1307-15. [PMID: 27208689 DOI: 10.1002/jor.23306] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Accepted: 05/11/2016] [Indexed: 02/04/2023]
Abstract
The inter-lamellar matrix (ILM) has an average thickness of less than 30 µm and lies between adjacent lamellae in the annulus fibrosus (AF). The microstructure and composition of the ILM have been studied in various anatomic regions of the disc; however, their contribution to AF mechanical properties and structural integrity is unknown. It was suggested that the ILM components, mainly elastic fibers and cross-bridges, play a role in providing mechanical integrity of the AF. Therefore, the manner in which they respond to different loadings and stabilize adjacent lamellae structure will influence AF tear formation and subsequent herniation. This review paper summarizes the composition, microstructure, and potential role of the ILM in the progression of disc herniation, clarifies the micromechanical properties of the ILM, and proposes critical areas for future studies. There are a number of unknown characteristics of the ILM, such as its mechanical role, impact on AF integrity, and ultrastructure of elastic fibers at the ILM-lamella boundary. Determining these characteristics will provide important information for tissue engineering, repair strategies, and the development of more-physiological computational models to study the initiation and propagation of AF tears that lead to herniation and degeneration. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1307-1315, 2016.
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Affiliation(s)
- Javad Tavakoli
- Biomechanics and Implants Research Group, The Medical Device Research Institute, School of Computer Science, Engineering and Mathematics, Flinders University, GPO Box 2100, Adelaide 5042, South Australia, Australia
| | - Dawn M Elliott
- Department of Biomedical Engineering, University of Delaware, Newark, Delaware
| | - John J Costi
- Biomechanics and Implants Research Group, The Medical Device Research Institute, School of Computer Science, Engineering and Mathematics, Flinders University, GPO Box 2100, Adelaide 5042, South Australia, Australia
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17
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Optical Coherence Tomographic Elastography Reveals Mesoscale Shear Strain Inhomogeneities in the Annulus Fibrosus. Spine (Phila Pa 1976) 2016; 41:E770-E777. [PMID: 26849796 PMCID: PMC4925193 DOI: 10.1097/brs.0000000000001463] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN Basic science study using in vitro tissue testing and imaging to characterize local strains in annulus fibrosus (AF) tissue. OBJECTIVE To characterize mesoscale strain inhomogeneities between lamellar and inter-/translamellar (ITL) matrix compartments during tissue shear loading. SUMMARY OF BACKGROUND DATA The intervertebral disc is characterized by significant heterogeneities in tissue structure and plays a critical role in load distribution and force transmission in the spine. In particular, the AF possesses a lamellar architecture interdigitated by a complex network of extracellular matrix components that form a distinct ITL compartment. Currently, there is not a firm understanding of how the lamellar and ITL matrix coordinately support tissue loading. METHODS AF tissue samples were prepared from frozen porcine lumbar spines and mounted onto custom fixtures of a materials testing system that incorporates optical coherence tomography (OCT) imaging to perform tissue elastography. Tissues were subjected to 20 and 40% nominal shear strain, and OCT images were captured and segmented to identify regions of interest corresponding to lamellar and ITL compartments. Images were analyzed using an optical flow algorithm to quantify local shear strains within each compartment. RESULTS Using histology and OCT, we first verified our ability to visualize and discriminate the ITL matrix from the lamellar matrix in porcine AF tissues. Local AF strains in the ITL compartment (22.0 ± 13.8, 31.1 ± 16.9 at 20% and 40% applied shear, respectively) were significantly higher than corresponding strains in the surrounding lamellar compartment (12.1 ± 5.6, 15.3 ± 5.2) for all tissue samples (P < 0.05). CONCLUSION Results from this study demonstrate that the lamellar and ITL compartments of the AF distribute strain unevenly during tissue loading. Specifically, shear strain is significantly higher in the ITL matrix, suggesting that these regions may be more susceptible to tissue damage and more mechanobiologically active. LEVEL OF EVIDENCE N/A.
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18
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Kobielarz M, Szotek S, Głowacki M, Dawidowicz J, Pezowicz C. Qualitative and quantitative assessment of collagen and elastin in annulus fibrosus of the physiologic and scoliotic intervertebral discs. J Mech Behav Biomed Mater 2016; 62:45-56. [PMID: 27177214 DOI: 10.1016/j.jmbbm.2016.04.033] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Revised: 04/15/2016] [Accepted: 04/25/2016] [Indexed: 02/02/2023]
Abstract
The biophysical properties of the annulus fibrosus of the intervertebral disc are determined by collagen and elastin fibres. The progression of scoliosis is accompanied by a number of pathological changes concerning these structural proteins. This is a major cause of dysfunction of the intervertebral disc. The object of the study were annulus fibrosus samples excised from intervertebral discs of healthy subjects and patients treated surgically for scoliosis in the thoracolumbar or lumbar spine. The research material was subjected to structural analysis by light microscopy and quantitative analysis of the content of collagen types I, II, III and IV as well as elastin by immunoenzymatic test (ELISA). A statistical analysis was conducted to assess the impact of the sampling site (Mann-Whitney test, α=0.05) and scoliosis (Wilcoxon matched pairs test, α=0.05) on the obtained results. The microscopic studies conducted on scoliotic annulus fibrosus showed a significant architectural distortion of collagen and elastin fibres. Quantitative biochemical assays demonstrated region-dependent distribution of only collagen types I and II in the case of healthy intervertebral discs whereas in the case of scoliotic discs region-dependent distribution concerned all examined proteins of the extracellular matrix. Comparison of scoliotic and healthy annulus fibrosus revealed a significant decrease in the content of collagen type I and elastin as well as a slight increase in the proportion of collagen types III and IV. The content of collagen type II did not differ significantly between both groups. The observed anomalies are a manifestation of degenerative changes affecting annulus fibrosus of the intervertebral disc in patients suffering from scoliosis.
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Affiliation(s)
- Magdalena Kobielarz
- Department of Biomedical Engineering, Mechatronics and Theory of Mechanisms, Wroclaw University of Technology, Łukasiewicza 7/9, 50-371 Wroclaw, Poland
| | - Sylwia Szotek
- Department of Biomedical Engineering, Mechatronics and Theory of Mechanisms, Wroclaw University of Technology, Łukasiewicza 7/9, 50-371 Wroclaw, Poland.
| | - Maciej Głowacki
- Department of Paediatric Orthopaedics, Karol Marcinkowski University of Medical Sciences, 28 Czerwca 1956r., 61-545 Poznan, Poland
| | | | - Celina Pezowicz
- Department of Biomedical Engineering, Mechatronics and Theory of Mechanisms, Wroclaw University of Technology, Łukasiewicza 7/9, 50-371 Wroclaw, Poland
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Abstract
Osteoarthritis (OA) is the most common chronic disease of our joints, manifested by a dynamically increasing degeneration of hyaline articular cartilage (AC). While currently no therapy can reverse this process, the few available treatment options are hampered by the inability of early diagnosis. Loss of cartilage surface, or extracellular matrix (ECM), integrity is considered the earliest sign of OA. Despite the increasing number of imaging modalities surprisingly few imaging biomarkers exist. In this narrative review, recent developments in optical coherence tomography are critically evaluated for their potential to assess different aspects of AC quality as biomarkers of OA. Special attention is paid to imaging surface irregularities, ECM organization and the evaluation of posttraumatic injuries by light-based modalities.
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Affiliation(s)
- Holger Jahr
- a Department of Orthopaedic Surgery , University Hospital RWTH Aachen University , Aachen , Germany
| | - Nicolai Brill
- b Fraunhofer Institute for Production Technology , Aachen , Germany , and
| | - Sven Nebelung
- a Department of Orthopaedic Surgery , University Hospital RWTH Aachen University , Aachen , Germany .,c Department of Anatomy and Cell Biology , University Hospital RWTH Aachen University , Aachen , Germany
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