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Swahn H, Mertens J, Olmer M, Myers K, Mondala TS, Natarajan P, Head SR, Alvarez‐Garcia O, Lotz MK. Shared and Compartment-Specific Processes in Nucleus Pulposus and Annulus Fibrosus During Intervertebral Disc Degeneration. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2309032. [PMID: 38403470 PMCID: PMC11077672 DOI: 10.1002/advs.202309032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Revised: 01/08/2024] [Indexed: 02/27/2024]
Abstract
Elucidating how cell populations promote onset and progression of intervertebral disc degeneration (IDD) has the potential to enable more precise therapeutic targeting of cells and mechanisms. Single-cell RNA-sequencing (scRNA-seq) is performed on surgically separated annulus fibrosus (AF) (19,978; 26,983 cells) and nucleus pulposus (NP) (20,884; 24,489 cells) from healthy and diseased human intervertebral discs (IVD). In both tissue types, depletion of cell subsets involved in maintenance of healthy IVD is observed, specifically the immature cell subsets - fibroblast progenitors and stem cells - indicative of an impairment of normal tissue self-renewal. Tissue-specific changes are also identified. In NP, several fibrotic populations are increased in degenerated IVD, indicating tissue-remodeling. In degenerated AF, a novel disease-associated subset is identified, which expresses disease-promoting genes. It is associated with pathogenic biological processes and the main gene regulatory networks include thrombospondin signaling and FOXO1 transcription factor. In NP and AF cells thrombospondin protein promoted expression of genes associated with TGFβ/fibrosis signaling, angiogenesis, and nervous system development. The data reveal new insights of both shared and tissue-specific changes in specific cell populations in AF and NP during IVD degeneration. These identified mechanisms and molecules are novel and more precise targets for IDD prevention and treatment.
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Affiliation(s)
- Hannah Swahn
- Department of Molecular and Cellular Biology & Department of Molecular MedicineScripps ResearchLa JollaCA92037USA
| | - Jasmin Mertens
- Department of Molecular and Cellular Biology & Department of Molecular MedicineScripps ResearchLa JollaCA92037USA
| | - Merissa Olmer
- Department of Molecular and Cellular Biology & Department of Molecular MedicineScripps ResearchLa JollaCA92037USA
| | - Kevin Myers
- Department of Molecular and Cellular Biology & Department of Molecular MedicineScripps ResearchLa JollaCA92037USA
| | - Tony S. Mondala
- Center for Computational Biology & Bioinformatics and Genomics CoreScripps ResearchLa JollaCA92037USA
| | - Padmaja Natarajan
- Center for Computational Biology & Bioinformatics and Genomics CoreScripps ResearchLa JollaCA92037USA
| | - Steven R. Head
- Center for Computational Biology & Bioinformatics and Genomics CoreScripps ResearchLa JollaCA92037USA
| | - Oscar Alvarez‐Garcia
- Department of Molecular and Cellular Biology & Department of Molecular MedicineScripps ResearchLa JollaCA92037USA
| | - Martin K. Lotz
- Department of Molecular and Cellular Biology & Department of Molecular MedicineScripps ResearchLa JollaCA92037USA
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Trębacz H, Barzycka A. Mechanical Properties and Functions of Elastin: An Overview. Biomolecules 2023; 13:biom13030574. [PMID: 36979509 PMCID: PMC10046833 DOI: 10.3390/biom13030574] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 03/08/2023] [Accepted: 03/20/2023] [Indexed: 03/30/2023] Open
Abstract
Human tissues must be elastic, much like other materials that work under continuous loads without losing functionality. The elasticity of tissues is provided by elastin, a unique protein of the extracellular matrix (ECM) of mammals. Its function is to endow soft tissues with low stiffness, high and fully reversible extensibility, and efficient elastic-energy storage. Depending on the mechanical functions, the amount and distribution of elastin-rich elastic fibers vary between and within tissues and organs. The article presents a concise overview of the mechanical properties of elastin and its role in the elasticity of soft tissues. Both the occurrence of elastin and the relationship between its spatial arrangement and mechanical functions in a given tissue or organ are overviewed. As elastin in tissues occurs only in the form of elastic fibers, the current state of knowledge about their mechanical characteristics, as well as certain aspects of degradation of these fibers and their mechanical performance, is presented. The overview also outlines the latest understanding of the molecular basis of unique physical characteristics of elastin and, in particular, the origin of the driving force of elastic recoil after stretching.
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Affiliation(s)
- Hanna Trębacz
- Department of Biophysics, Medical University of Lublin, Al. Racławickie 1, 20-059 Lublin, Poland
| | - Angelika Barzycka
- Department of Biophysics, Medical University of Lublin, Al. Racławickie 1, 20-059 Lublin, Poland
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Briar KJ, Gregory DE. Combined flexion and compression negatively impact the mechanical integrity of the annulus fibrosus. EUROPEAN SPINE JOURNAL : OFFICIAL PUBLICATION OF THE EUROPEAN SPINE SOCIETY, THE EUROPEAN SPINAL DEFORMITY SOCIETY, AND THE EUROPEAN SECTION OF THE CERVICAL SPINE RESEARCH SOCIETY 2023; 32:831-838. [PMID: 36631712 DOI: 10.1007/s00586-022-07518-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Revised: 11/23/2022] [Accepted: 12/23/2022] [Indexed: 01/13/2023]
Abstract
PURPOSE To observe the effect of static flexion, in combination with compression, on the intralamellar and interlamellar matrix properties of the annulus fibrosus. METHODS C3/C4 cervical functional spinal units of porcine specimens were selected. Following preloading, all specimens were loaded under 1200 N axial compression in either a neutral or static end range flexion posture (15º) for 2 h. Following loading, six annulus samples were dissected from each disc: four single-layer and two multi-layer samples. The multi-layer samples underwent peel tests to quantify the mechanical properties of the interlamellar matrix while the single-layer samples underwent tensile tests to quantify the mechanical properties of the intralamellar matrix. Statistical comparisons between properties were performed to determine differences between postural condition, extraction location, and extraction depth. RESULTS Flexion elicited a decrease in lamellar adhesive strength (p = 0.045) and in single-layer failure strain (p = 0.03) when compared to a neutral posture. Flexion also had extraction depth-specific effects namely increased intralamellar matrix stiffness in the inner annulus when compared to neutral (p = 0019). Flexion also resulted in a significant decrease in toe region strain for the inner region of the annulus (p = 0.035). The inner region of the annulus was shown to have a significant increase in stress at 30% strain when compared to the outer region after flexion (p = 0.041). CONCLUSION The current findings suggest that the mechanical properties of the interlamellar and intralamellar matrices are sensitive to flexion, creating an environment that promotes an increased potential for damage to occur.
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Affiliation(s)
- K Josh Briar
- Department of Kinesiology and Physical Education, Wilfrid Laurier University, Waterloo, ON, Canada
| | - Diane E Gregory
- Department of Kinesiology and Physical Education, Wilfrid Laurier University, Waterloo, ON, Canada. .,Department of Health Sciences, Wilfrid Laurier University, Waterloo, ON, Canada.
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4
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Eckersley A, Ozols M, Chen P, Tam V, Ward LJ, Hoyland JA, Trafford A, Yuan XM, Schiller HB, Chan D, Sherratt MJ. Peptide location fingerprinting identifies species- and tissue-conserved structural remodelling of proteins as a consequence of ageing and disease. Matrix Biol 2022; 114:108-137. [PMID: 35618217 DOI: 10.1016/j.matbio.2022.05.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 05/12/2022] [Accepted: 05/19/2022] [Indexed: 12/30/2022]
Abstract
Extracellular matrices (ECMs) in the intervertebral disc (IVD), lung and artery are thought to undergo age-dependant accumulation of damage by chronic exposure to mechanisms such as reactive oxygen species, proteases and glycation. It is unknown whether this damage accumulation is species-dependant (via differing lifespans and hence cumulative exposures) or whether it can influence the progression of age-related diseases such as atherosclerosis. Peptide location fingerprinting (PLF) is a new proteomic analysis method, capable of the non-targeted identification of structure-associated changes within proteins. Here we applied PLF to publicly available ageing human IVD (outer annulus fibrosus), ageing mouse lung and human arterial atherosclerosis datasets and bioinformatically identified novel target proteins alongside common age-associated differences within protein structures which were conserved between three ECM-rich organs, two species, three IVD tissue regions, sexes and in an age-related disease. We identify peptide yield differences across protein structures which coincide with biological regions, potentially reflecting the functional consequences of ageing or atherosclerosis for macromolecular assemblies (collagen VI), enzyme/inhibitor activity (alpha-2 macroglobulin), activation states (complement C3) and interaction states (laminins, perlecan, fibronectin, filamin-A, collagen XIV and apolipoprotein-B). Furthermore, we show that alpha-2 macroglobulin and collagen XIV exhibit possible shared structural consequences in IVD ageing and arterial atherosclerosis, providing novel links between an age-related disease and intrinsic ageing. Crucially, we also demonstrate that fibronectin, laminin beta chains and filamin-A all exhibit conserved age-associated structural differences between mouse lung and human IVD, providing evidence that ECM, and their associating proteins, may be subjected to potentially similar mechanisms or consequences of ageing across both species, irrespective of differences in lifespan and tissue function.
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Affiliation(s)
- Alexander Eckersley
- Division of Cell Matrix Biology & Regenerative Medicine, School of Biological Science, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom.
| | - Matiss Ozols
- Division of Cell Matrix Biology & Regenerative Medicine, School of Biological Science, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom; Department of Human Genetics, Wellcome Sanger Institute, Genome Campus, Hinxton, United Kingdom; British Heart Foundation Centre of Research Excellence, University of Cambridge, Cambridge, United Kingdom
| | - Peikai Chen
- Department of Orthopaedics and Traumatology, The University of Hong Kong-Shenzhen Hospital (HKU-SZH), Shenzhen, Guangdong 518053, China
| | - Vivian Tam
- School of Biomedical Sciences, The University of Hong Kong, Hong Kong, China
| | - Liam J Ward
- Department of Clinical Science, Intervention and Technology, Karolinska Institutet, Stockholm, Sweden; Department of Forensic Genetics and Forensic Toxicology, National Board of Forensic Medicine, Linköping, Sweden
| | - Judith A Hoyland
- Division of Cell Matrix Biology & Regenerative Medicine, School of Biological Science, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom
| | - Andrew Trafford
- Division of Cardiovascular Sciences, School of Biological Science, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom
| | - Xi-Ming Yuan
- Occupational and Environmental Medicine, Division of Prevention, Rehabilitation and Community Medicine, Department of Health, Medicine and Caring Sciences, Linköping University, Linköping, Sweden
| | - Herbert B Schiller
- Institute of Lung Health and Immunity and Comprehensive Pneumology Center, Helmholtz Munich, Member of the German Center for Lung Research (DZL), Munich, Germany
| | - Danny Chan
- School of Biomedical Sciences, The University of Hong Kong, Hong Kong, China
| | - Michael J Sherratt
- Division of Cell Matrix Biology & Regenerative Medicine, School of Biological Science, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, United Kingdom.
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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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6
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Zhang S, Liu W, Chen S, Wang B, Wang P, Hu B, Lv X, Shao Z. Extracellular matrix in intervertebral disc: basic and translational implications. Cell Tissue Res 2022; 390:1-22. [DOI: 10.1007/s00441-022-03662-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2022] [Accepted: 06/23/2022] [Indexed: 02/06/2023]
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Briar KJ, McMorran JG, Gregory DE. Delamination of the Annulus Fibrosus of the Intervertebral Disc: Using a Bovine Tail Model to Examine Effect of Separation Rate. Front Bioeng Biotechnol 2022; 10:883268. [PMID: 35837552 PMCID: PMC9273995 DOI: 10.3389/fbioe.2022.883268] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Accepted: 06/09/2022] [Indexed: 11/13/2022] Open
Abstract
The intervertebral disc (IVD) is a complex structure, and recent evidence suggests that separations or delamination between layers of the annulus may contribute to degeneration development, a common cause of low back pain The purpose of the present experiment was to quantify the mechanical response of the layer-adjoining interlamellar matrix at different rates of separation. Understanding the rate-dependency of the interlamellar matrix, or the adhesion between adjacent layers of the disc, is important as the spine experiences various loading velocities during activities of daily living. Twelve discs were dissected from four bovine tails (three extracts per tail). Two multi-layered annulus samples were collected from each IVD (total = 24, mean bond width = 3.82 ± 0.96 mm) and randomly assigned to a 180° peel test at one of three delamination rates; 0.05 mm/s, 0.5 mm/s, or 5 mm/s. Annulus extracts were found to have similar maximal adhesion strengths (p = 0.39) and stiffness (p = 0.97) across all rate conditions. However, a significant difference in lamellar adhesion strength variability was observed between the 5 mm/s condition (0.96 N/mm ± 0.31) when compared to the 0.5 mm/s (0.50 N/mm ± 0.19) and 0.05 mm/s (0.37 N/mm ± 0.13) conditions (p < 0.05). Increased variability may be indicative of non-uniform strength due to inconsistent adhesion throughout the interlamellar matrix, which is exacerbated by increased rates of loading. The observed non-uniform strength could possibly lead to a scenario more favourable to the development of microtrauma, and eventual delamination.
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Affiliation(s)
- K. Josh Briar
- Department of Kinesiology and Physical Education, Wilfrid Laurier University, Waterloo, ON, Canada
| | - John G. McMorran
- Department of Kinesiology and Physical Education, Wilfrid Laurier University, Waterloo, ON, Canada
| | - Diane E. Gregory
- Department of Kinesiology and Physical Education, Wilfrid Laurier University, Waterloo, ON, Canada
- Department of Health Sciences, Wilfrid Laurier University, Waterloo, ON, Canada
- *Correspondence: Diane E. Gregory,
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8
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Importance of Matrix Cues on Intervertebral Disc Development, Degeneration, and Regeneration. Int J Mol Sci 2022; 23:ijms23136915. [PMID: 35805921 PMCID: PMC9266338 DOI: 10.3390/ijms23136915] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 06/17/2022] [Accepted: 06/20/2022] [Indexed: 01/25/2023] Open
Abstract
Back pain is one of the leading causes of disability worldwide and is frequently caused by degeneration of the intervertebral discs. The discs’ development, homeostasis, and degeneration are driven by a complex series of biochemical and physical extracellular matrix cues produced by and transmitted to native cells. Thus, understanding the roles of different cues is essential for designing effective cellular and regenerative therapies. Omics technologies have helped identify many new matrix cues; however, comparatively few matrix molecules have thus far been incorporated into tissue engineered models. These include collagen type I and type II, laminins, glycosaminoglycans, and their biomimetic analogues. Modern biofabrication techniques, such as 3D bioprinting, are also enabling the spatial patterning of matrix molecules and growth factors to direct regional effects. These techniques should now be applied to biochemically, physically, and structurally relevant disc models incorporating disc and stem cells to investigate the drivers of healthy cell phenotype and differentiation. Such research will inform the development of efficacious regenerative therapies and improved clinical outcomes.
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9
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Lopez SG, Bonassar LJ. The role of SLRPs and large aggregating proteoglycans in collagen fibrillogenesis, extracellular matrix assembly, and mechanical function of fibrocartilage. Connect Tissue Res 2022; 63:269-286. [PMID: 33726572 DOI: 10.1080/03008207.2021.1903887] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
PURPOSE Proteoglycans, especially small leucine rich proteoglycans (SLRPs), play major roles in facilitating the development and regulation of collagen fibers and other extracellular matrix components. However, their roles in fibrocartilage have not been widely reviewed. Here, we discuss both SLRP and large aggregating proteoglycan's roles in collagen fibrillogenesis and extracellular matrix assembly in fibrocartilage tissues such as the meniscus, annulus fibrosus (AF), and TMJ disc. We also discuss their expression levels throughout development, aging and degeneration, as well as repair. METHODS A review of literature discussing proteoglycans and collagen fibrillogenesis in fibrocartilage was conducted and data from these manuscripts were analyzed and grouped to discuss trends throughout the tissue's architectural zones and developmental stage. RESULTS The spatial collagen architecture of these fibrocartilaginous tissues is reflected in the distribution of proteoglycans expressed, suggesting that each proteoglycan plays an important role in the type of architecture presented and associated mechanical function. CONCLUSION The unique structure-function relationship of fibrocartilage makes the varied architectures throughout the tissues imperative for their success and understanding the functions of these proteoglycans in developing and maintaining the fiber structure could inform future work in fibrocartilage replacement using tissue engineered constructs.
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Affiliation(s)
- Serafina G Lopez
- Meinig of Biomedical Engineering, Cornell University, Ithaca, NY, USA
| | - Lawrence J Bonassar
- Meinig of Biomedical Engineering, Cornell University, Ithaca, NY, USA.,Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, NY, USA
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10
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Modeling multiaxial damage regional variation in human annulus fibrosus. Acta Biomater 2021; 136:375-388. [PMID: 34547514 DOI: 10.1016/j.actbio.2021.09.017] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Revised: 09/08/2021] [Accepted: 09/13/2021] [Indexed: 01/03/2023]
Abstract
In the present article, a fully three-dimensional human annulus fibrosus model is developed by considering the regional variation of the complex structural organization of collagen network at different scales to predict the regional anisotropic multiaxial damage of the intervertebral disc. The model parameters are identified using experimental data considering as elementary structural unit, the single annulus lamellae stretched till failure along the micro-sized collagen fibers. The multi-layered lamellar/inter-lamellar annulus model is constructed by considering the effective interactions between adjacent layers and the chemical-induced volumetric strain. The regional dependent model predictions are analyzed under various loading modes and compared to experimental data when available. The stretching along the circumferential and radial directions till failure serves to check the predictive capacities of the annulus model. Model results under simple shear, biaxial stretching and plane-strain compression are further presented and discussed. Finally, a full disc model is constructed using the regional annulus model and simulations are presented to assess the most likely failed areas under disc axial compression. STATEMENT OF SIGNIFICANCE: The damage in annulus soft tissues is a complex multiscale phenomenon due to a complex structural arrangement of collagen network at different scales of hierarchical organization. A fully three-dimensional constitutive representation that considers the regional variation of the structural complexity to estimate annulus multiaxial mechanics till failure has not yet been developed. Here, a model is developed to predict deformation-induced damage and failure of annulus under multiaxial loading histories considering as time-dependent physical process both chemical-induced volumetric effects and damage accumulation. After model identification using single lamellae extracted from different disc regions, the model predictability is verified for various multiaxial elementary loading modes representative of the spine movement. The heterogeneous mechanics of a full human disc model is finally presented.
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Kirnaz S, Capadona C, Lintz M, Kim B, Yerden R, Goldberg JL, Medary B, Sommer F, McGrath LB, Bonassar LJ, Härtl R. Pathomechanism and Biomechanics of Degenerative Disc Disease: Features of Healthy and Degenerated Discs. Int J Spine Surg 2021; 15:10-25. [PMID: 34376493 DOI: 10.14444/8052] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The human intervertebral disc (IVD) is a complex organ composed of fibrous and cartilaginous connective tissues, and it serves as a boundary between 2 adjacent vertebrae. It provides a limited range of motion in the torso as well as stability during axial compression, rotation, and bending. Adult IVDs have poor innate healing potential due to low vascularity and cellularity. Degenerative disc disease (DDD) generally arises from the disruption of the homeostasis maintained by the structures of the IVD, and genetic and environmental factors can accelerate the progression of the disease. Impaired cell metabolism due to pH alteration and poor nutrition may lead to autophagy and disruption of the homeostasis within the IVD and thus plays a key role in DDD etiology. To develop regenerative therapies for degenerated discs, future studies must aim to restore both anatomical and biomechanical properties of the IVDs. The objective of this review is to give a detailed overview about anatomical, radiological, and biomechanical features of the IVDs as well as discuss the structural and functional changes that occur during the degeneration process.
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Affiliation(s)
- Sertac Kirnaz
- Department of Neurological Surgery, Weill Cornell Brain and Spine Center, Weill Cornell Medicine, New York Presbyterian Hospital, New York, New York
| | - Charisse Capadona
- Department of Neurological Surgery, Weill Cornell Brain and Spine Center, Weill Cornell Medicine, New York Presbyterian Hospital, New York, New York
| | - Marianne Lintz
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, New York
| | - Byumsu Kim
- Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, New York
| | - Rachel Yerden
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, New York
| | - Jacob L Goldberg
- Department of Neurological Surgery, Weill Cornell Brain and Spine Center, Weill Cornell Medicine, New York Presbyterian Hospital, New York, New York
| | - Branden Medary
- Department of Neurological Surgery, Weill Cornell Brain and Spine Center, Weill Cornell Medicine, New York Presbyterian Hospital, New York, New York
| | - Fabian Sommer
- Department of Neurological Surgery, Weill Cornell Brain and Spine Center, Weill Cornell Medicine, New York Presbyterian Hospital, New York, New York
| | - Lynn B McGrath
- Department of Neurological Surgery, Weill Cornell Brain and Spine Center, Weill Cornell Medicine, New York Presbyterian Hospital, New York, New York
| | - Lawrence J Bonassar
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, New York.,Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, New York
| | - Roger Härtl
- Department of Neurological Surgery, Weill Cornell Brain and Spine Center, Weill Cornell Medicine, New York Presbyterian Hospital, New York, New York
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12
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Ghezelbash F, Eskandari AH, Shirazi-Adl A, Kazempour M, Tavakoli J, Baghani M, Costi JJ. Modeling of human intervertebral disc annulus fibrosus with complex multi-fiber networks. Acta Biomater 2021; 123:208-221. [PMID: 33453409 DOI: 10.1016/j.actbio.2020.12.062] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 12/07/2020] [Accepted: 12/21/2020] [Indexed: 12/21/2022]
Abstract
Collagen fibers within the annulus fibrosus (AF) lamellae are unidirectionally aligned with alternating orientations between adjacent layers. AF constitutive models often combine two adjacent lamellae into a single equivalent layer containing two fiber networks with a crisscross pattern. Additionally, AF models overlook the inter-lamellar matrix (ILM) as well as elastic fiber networks in between lamellae. We developed a nonhomogenous micromechanical model as well as two coarser homogenous hyperelastic and microplane models of the human AF, and compared their performances against measurements (tissue level uniaxial and biaxial tests as well as whole disc experiments) and seven published hyperelastic models. The micromechanical model had a realistic non-homogenous distribution of collagen fiber networks within each lamella and elastic fiber network in the ILM. For small matrix linear moduli (<0.2 MPa), the ILM showed substantial anisotropy (>10%) due to the elastic fiber network. However, at moduli >0.2 MPa, the effects of the elastic fiber network on differences in stress-strain responses at different directions disappeared (<10%). Variations in sample geometry and boundary conditions (due to uncertainty) markedly affected stress-strain responses of the tissue in uniaxial and biaxial tests (up to 16 times). In tissue level tests, therefore, simulations should represent testing conditions (e.g., boundary conditions, specimen geometry, preloads) as closely as possible. Stress/strain fields estimated from the single equivalent layer approach (conventional method) yielded different results from those predicted by the anatomically more accurate apparoach (i.e., layerwise). In addition, in a disc under a compressive force (symmetric loading), asymmetric stress-strain distributions were computed when using a layerwise simulation. Although all developed and selected published AF models predicted gross compression-displacement responses of the whole disc within the range of measured data, some showed excessively stiff or compliant responses under tissue-level uniaxial/biaxial tests. This study emphasizes, when constructing and validating constitutive models of AF, the importance of the proper simulation of individual lamellae as distinct layers, and testing parameters (sample geometric dimensions/loading/boundary conditions).
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Affiliation(s)
- Farshid Ghezelbash
- Department of Mechanical Engineering, Polytechnique Montreal, Quebec, Canada.
| | - Amir Hossein Eskandari
- Institut de recherche Robert Sauvé en santé et en sécurité du travail, Montréal, Québec, Canada
| | | | - Morteza Kazempour
- Mechanical Engineering Department, University of Tehran, Tehran, Iran
| | - Javad Tavakoli
- Centre for Health Technologies, School of Biomedical Engineering, Faculty of Engineering and Information Technology, University of Technology Sydney, NSW, Australia; SpineLabs, St George & Sutherland Clinical School, The University of New South Wales, NSW, Australia
| | - Mostafa Baghani
- Mechanical Engineering Department, University of Tehran, Tehran, Iran
| | - John J Costi
- Biomechanics and Implants Research Group, Medical Device Research Institute, College of Science and Engineering, Flinders University, Adelaide, Australia
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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.
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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
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14
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Zwambag DP, Molladavoodi S, Guerreiro MJ, DeWitte-Orr SJ, Gregory DE. Immuno-stimulatory capacity of decorin in the rat tail intervertebral disc and the mechanical consequence of resultant inflammation. EUROPEAN SPINE JOURNAL : OFFICIAL PUBLICATION OF THE EUROPEAN SPINE SOCIETY, THE EUROPEAN SPINAL DEFORMITY SOCIETY, AND THE EUROPEAN SECTION OF THE CERVICAL SPINE RESEARCH SOCIETY 2020; 29:1641-1648. [PMID: 32451779 DOI: 10.1007/s00586-020-06469-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 04/27/2020] [Accepted: 05/14/2020] [Indexed: 02/06/2023]
Abstract
PURPOSE Determine whether decorin is immuno-stimulatory to rat tail IVD cells and to characterize the mechanical consequence of inflammation at the whole rat tail IVD level. METHODS Cultured rat tail annulus fibrosus (AF) cells were exposed to decorin, a resident IVD small leucine-rich proteoglycan (SLRP), with and without the presence of a toll-like receptor (TLR) 4 inhibitor, TAK-242. Resultant expression of pro-inflammatory cytokine and chemokines (MCP-1; MIP-2; RANTES; IL-6; TNFα) were quantified over 24 h. Whole rat tail IVD cultures (n = 50) were also treated with decorin (two concentrations: 0.5 and 5.0 μg/mL) with and without TAK-242 (via nucleus pulpous injection with a 33-gauge needle), and resultant mechanical properties were measured. RESULTS AF cells exposed to decorin showed significant increases in pro-inflammatory cytokine and chemokine production; this was significantly blunted with the presence of TAK-242. Whole IVDs injected with decorin showed a dose-dependent decrease in neutral zone and tensile stiffness and an increase in neutral zone size. When TAK-242 was injected into the IVD with the decorin, mechanical stiffness was preserved and not different from sham controls (injected with PBS). CONCLUSION AF cells are capable of detecting decorin and inducing inflammation. Decorin further resulted in a functional deterioration in IVD mechanical integrity. TAK- 242, a TLR4 inhibitor, blunted chemokine production at the cellular level and preserved mechanical stiffness in the whole IVD.
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Affiliation(s)
- Derek P Zwambag
- Department of Kinesiology and Physical Education, Wilfrid Laurier University, 75 University Ave W, Waterloo, ON, N2L 3C5, Canada
| | - Sara Molladavoodi
- Department of Kinesiology and Physical Education, Wilfrid Laurier University, 75 University Ave W, Waterloo, ON, N2L 3C5, Canada
| | - Matthew J Guerreiro
- Department of Integrative Biology, Wilfrid Laurier University, Waterloo, ON, Canada
| | - Stephanie J DeWitte-Orr
- Department of Integrative Biology, Wilfrid Laurier University, Waterloo, ON, Canada.,Department of Health Sciences, Wilfrid Laurier University, Waterloo, ON, Canada
| | - Diane E Gregory
- Department of Kinesiology and Physical Education, Wilfrid Laurier University, 75 University Ave W, Waterloo, ON, N2L 3C5, Canada. .,Department of Health Sciences, Wilfrid Laurier University, Waterloo, ON, Canada.
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15
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Xu G, Liu Y, Zhang C, Zhou Y, Hou S, Tang J, Li Z. Temporal and spatial expression of Sox9, Pax1, TGF-β1 and type I and II collagen in human intervertebral disc development. Neurochirurgie 2020; 66:168-173. [PMID: 32201238 DOI: 10.1016/j.neuchi.2019.12.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Revised: 11/06/2019] [Accepted: 12/08/2019] [Indexed: 10/24/2022]
Abstract
PURPOSE An accurate understanding of cellular biochemical changes in human intervertebral disc (IVD)s and the corresponding mechanisms during the developmental process still remain unknown and important for investigating the function of critical factors in normal IVD development as well as ascertaining the therapeutic targets for the IVD degeneration. METHODS Under ethical conditions, human fetal cervical IVDs at 4, 5, and 6 months of pregnancy were collected at abortion surgery. Normal adult human C3-C7 cervical IVDs were taken from cadaveric donors. Sox9, Pax1, TGF-β1 and type I/II collagen protein and RNA were detected. The number of positive cells was counted to calculate the optical density value for each factor. RESULTS Sox9, Pax1, and TGF-β1 expression in the IVD was remarkably reduced with the developmental stage. The location of high expression of Sox9, Pax1, and TGF-β1 changed with the developmental stage, and migrated from the nucleus pulposus to the annulus fibrosus and endplate. Higher Sox9, Pax1, and TGF-β1 expression was finally observed around the sclerotome of the vertebral body. The anabolism of type I/II collagens is significantly increased in the IVD in the mid-trimester fetus. CONCLUSIONS Sox9, Pax1 and TGF-β1 participate in the developmental process of the human IVD and vertebral body. However, these factors show a separate expression of mRNA and protein, suggesting that they are expressed in the strict time and spatial order.
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Affiliation(s)
- G Xu
- Key Laboratory of Molecular Mechanism for Repair and Remodeling of Orthopaedic Diseases Liaoning Province, Department of Orthopaedics, First Affiliated Hospital of Dalian Medical University, 116011 Dalian, People's Republic of China
| | - Y Liu
- Department of Orthopedics, First Affiliated Hospital of PLA General Hospital, 100048 Beijing, People's Republic of China
| | - C Zhang
- Department of Orthopedics, First Affiliated Hospital of PLA General Hospital, 100048 Beijing, People's Republic of China
| | - Y Zhou
- Department of Orthopedics, First Affiliated Hospital of PLA General Hospital, 100048 Beijing, People's Republic of China
| | - S Hou
- Department of Orthopedics, First Affiliated Hospital of PLA General Hospital, 100048 Beijing, People's Republic of China
| | - J Tang
- Department of Orthopedics, First Affiliated Hospital of PLA General Hospital, 100048 Beijing, People's Republic of China.
| | - Z Li
- Key Laboratory of Molecular Mechanism for Repair and Remodeling of Orthopaedic Diseases Liaoning Province, Department of Orthopaedics, First Affiliated Hospital of Dalian Medical University, 116011 Dalian, People's Republic of China.
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16
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Molladavoodi S, McMorran J, Gregory D. Mechanobiology of annulus fibrosus and nucleus pulposus cells in intervertebral discs. Cell Tissue Res 2019; 379:429-444. [PMID: 31844969 DOI: 10.1007/s00441-019-03136-1] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Accepted: 11/03/2019] [Indexed: 02/07/2023]
Abstract
Low back pain (LBP) is a chronic condition that can affect up to 80% of the global population. It is the number one cause of disability worldwide and has enormous socioeconomic consequences. One of the main causes of this condition is intervertebral disc (IVD) degeneration. IVD degenerative processes and inflammation associated with it has been the subject of many studies in both tissue and cell level. It is believed that the phenotype of the resident cells within the IVD directly affects homeostasis of the tissue. At the same time, IVDs located between vertebral bodies of spine are under various mechanical loading conditions in vivo. Therefore, investigating how mechanical loading can affect the behaviour of IVD cells has been a subject of many research articles. In this review paper, following a brief explanation of the anatomy of the IVD and its resident cells, we compiled mechanobiological studies of IVD cells (specifically, annulus fibrosus and nucleus pulposus cells) and synthesized and discussed the key findings of the field.
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Affiliation(s)
- Sara Molladavoodi
- Department of Kinesiology and Physical Education, Wilfrid Laurier University, Waterloo, ON, Canada.,Department of Health Sciences, Wilfrid Laurier University, Waterloo, ON, Canada
| | - John McMorran
- Department of Kinesiology and Physical Education, Wilfrid Laurier University, Waterloo, ON, Canada
| | - Diane Gregory
- Department of Kinesiology and Physical Education, Wilfrid Laurier University, Waterloo, ON, Canada. .,Department of Health Sciences, Wilfrid Laurier University, Waterloo, ON, Canada.
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17
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Zhao R, Liu W, Xia T, Yang L. Disordered Mechanical Stress and Tissue Engineering Therapies in Intervertebral Disc Degeneration. Polymers (Basel) 2019; 11:polym11071151. [PMID: 31284436 PMCID: PMC6680713 DOI: 10.3390/polym11071151] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2019] [Revised: 06/27/2019] [Accepted: 07/01/2019] [Indexed: 12/11/2022] Open
Abstract
Low back pain (LBP), commonly induced by intervertebral disc degeneration, is a lumbar disease with worldwide prevalence. However, the mechanism of degeneration remains unclear. The intervertebral disc is a nonvascular organ consisting of three components: Nucleus pulposus, annulus fibrosus, and endplate cartilages. The disc is structured to support our body motion and endure persistent external mechanical pressure. Thus, there is a close connection between force and intervertebral discs in LBP. It is well established that with aging, disordered mechanical stress profoundly influences the fate of nucleus pulposus and the alignment of collagen fibers in the annulus fibrosus. These support a new understanding that disordered mechanical stress plays an important role in the degeneration of the intervertebral discs. Tissue-engineered regenerative and reparative therapies are being developed for relieving disc degeneration and symptoms of lower back pain. In this paper, we will review the current literature available on the role of disordered mechanical stress in intervertebral disc degeneration, and evaluate the existing tissue engineering treatment strategies of the current therapies.
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Affiliation(s)
- Runze Zhao
- Key Laboratory of Biorheological Science and Technology, Ministry of Education, Bioengineering College, Chongqing University, Chongqing 400044, China
| | - Wanqian Liu
- Key Laboratory of Biorheological Science and Technology, Ministry of Education, Bioengineering College, Chongqing University, Chongqing 400044, China
| | - Tingting Xia
- Key Laboratory of Biorheological Science and Technology, Ministry of Education, Bioengineering College, Chongqing University, Chongqing 400044, China.
| | - Li Yang
- Key Laboratory of Biorheological Science and Technology, Ministry of Education, Bioengineering College, Chongqing University, Chongqing 400044, China.
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18
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Saggese T, Teixeira GQ, Wade K, Moll L, Ignatius A, Wilke HJ, Goncalves RM, Neidlinger-Wilke C. GEORG SCHMORL PRIZE OF THE GERMAN SPINE SOCIETY (DWG) 2018: combined inflammatory and mechanical stress weakens the annulus fibrosus: evidences from a loaded bovine AF organ culture. EUROPEAN SPINE JOURNAL : OFFICIAL PUBLICATION OF THE EUROPEAN SPINE SOCIETY, THE EUROPEAN SPINAL DEFORMITY SOCIETY, AND THE EUROPEAN SECTION OF THE CERVICAL SPINE RESEARCH SOCIETY 2019; 28:922-933. [PMID: 30689044 DOI: 10.1007/s00586-019-05901-w] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Revised: 01/15/2019] [Accepted: 01/18/2019] [Indexed: 12/19/2022]
Abstract
PURPOSE The pathomechanism of annulus fibrosus (AF) failure is still unknown. We hypothesise that mechanical overload and an inflammatory microenvironment contribute to AF structural weakening. Therefore, the objective of this study was to investigate the influence of these factors on the AF, particularly the translamellar bridging network (TLBN) which connects the AF lamellae. METHODS A bovine AF organ culture (AF-OC) model of standardised AF rings was used to study the individual and combined effects of cyclic tensile strain (CTS) and IL-1β (1 ng/mL) culture medium supplementation. AF-OCs were analysed for PGE2 production (ELISA) and deposition of IL-6, COX-2, fibrillin, and MMP3 in the tissue (immunohistochemistry, IHC). The mechanical strength of the TLBN was evaluated using a peel test to measure the strength required to separate an AF segment along a lamellar bound. RESULTS The combination of CTS + IL-1β led to a significant increase in PGE2 production compared to Control (p < 0.01). IHC evaluations showed that the CTS + IL-1β group exhibited higher production of COX-2 and MMP3 within the TLBN regions compared to the adjacent lamellae and a significant increase in IL-6 ratio compared to Control (p < 0.05). A significant decrease in the annular peel strength was observed in the CTS + IL1β group compared to Control (p < 0.05). CONCLUSION Our findings suggest that CTS and IL-1β act synergistically to increase pro-inflammatory and catabolic molecules within the AF, particularly the TLBN, leading to a weakening of the tissue. This standardised model enables the investigation of AF/TLBN structure-function relationship and is a platform to test AF-focused therapeutics. These slides can be retrieved under Electronic Supplementary Material.
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Affiliation(s)
- Taryn Saggese
- Institute of Orthopaedic Research and Biomechanics, Trauma Research Centre, Ulm University, Helmholtzstraße 14, 89081, Ulm, Germany
| | - Graciosa Q Teixeira
- Institute of Orthopaedic Research and Biomechanics, Trauma Research Centre, Ulm University, Helmholtzstraße 14, 89081, Ulm, Germany
| | - Kelly Wade
- Institute of Orthopaedic Research and Biomechanics, Trauma Research Centre, Ulm University, Helmholtzstraße 14, 89081, Ulm, Germany
| | - Lydia Moll
- Institute of Orthopaedic Research and Biomechanics, Trauma Research Centre, Ulm University, Helmholtzstraße 14, 89081, Ulm, Germany
| | - Anita Ignatius
- Institute of Orthopaedic Research and Biomechanics, Trauma Research Centre, Ulm University, Helmholtzstraße 14, 89081, Ulm, Germany
| | - Hans-Joachim Wilke
- Institute of Orthopaedic Research and Biomechanics, Trauma Research Centre, Ulm University, Helmholtzstraße 14, 89081, Ulm, Germany
| | - Raquel M Goncalves
- Institute of Orthopaedic Research and Biomechanics, Trauma Research Centre, Ulm University, Helmholtzstraße 14, 89081, Ulm, Germany.,Instituto de Investigação e Inovação em Saúde (i3S), Universidade do Porto, R. Alfredo Allen, 4200-135, Porto, Portugal.,Instituto de Engenharia Biomédica (INEB), Universidade do Porto, R. Alfredo Allen, 4200-135, Porto, Portugal.,Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, R. Jorge de Viterbo Ferreira 228, 4050-313, Porto, Portugal
| | - Cornelia Neidlinger-Wilke
- Institute of Orthopaedic Research and Biomechanics, Trauma Research Centre, Ulm University, Helmholtzstraße 14, 89081, Ulm, Germany.
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19
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Frost BA, Camarero-Espinosa S, Foster EJ. Materials for the Spine: Anatomy, Problems, and Solutions. MATERIALS (BASEL, SWITZERLAND) 2019; 12:E253. [PMID: 30646556 PMCID: PMC6356370 DOI: 10.3390/ma12020253] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Revised: 12/28/2018] [Accepted: 01/05/2019] [Indexed: 12/24/2022]
Abstract
Disc degeneration affects 12% to 35% of a given population, based on genetics, age, gender, and other environmental factors, and usually occurs in the lumbar spine due to heavier loads and more strenuous motions. Degeneration of the extracellular matrix (ECM) within reduces mechanical integrity, shock absorption, and swelling capabilities of the intervertebral disc. When severe enough, the disc can bulge and eventually herniate, leading to pressure build up on the spinal cord. This can cause immense lower back pain in individuals, leading to total medical costs exceeding $100 billion. Current treatment options include both invasive and noninvasive methods, with spinal fusion surgery and total disc replacement (TDR) being the most common invasive procedures. Although these treatments cause pain relief for the majority of patients, multiple challenges arise for each. Therefore, newer tissue engineering methods are being researched to solve the ever-growing problem. This review spans the anatomy of the spine, with an emphasis on the functions and biological aspects of the intervertebral discs, as well as the problems, associated solutions, and future research in the field.
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Affiliation(s)
- Brody A Frost
- Department of Materials Science and Engineering, Macromolecules Innovation Institute, Virginia Tech, Blacksburg, VA 24061, USA.
| | - Sandra Camarero-Espinosa
- Complex Tissue Regeneration Department, MERLN Institute for Technology-inspired Regenerative Medicine, Maastricht University, P.O. Box 616, 6200MD Maastricht, The Netherlands.
| | - E Johan Foster
- Department of Materials Science and Engineering, Macromolecules Innovation Institute, Virginia Tech, Blacksburg, VA 24061, USA.
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20
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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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21
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Coenen AMJ, Bernaerts KV, Harings JAW, Jockenhoevel S, Ghazanfari S. Elastic materials for tissue engineering applications: Natural, synthetic, and hybrid polymers. Acta Biomater 2018; 79:60-82. [PMID: 30165203 DOI: 10.1016/j.actbio.2018.08.027] [Citation(s) in RCA: 87] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Revised: 08/03/2018] [Accepted: 08/21/2018] [Indexed: 02/08/2023]
Abstract
Elastin and collagen are the two main components of elastic tissues and provide the tissue with elasticity and mechanical strength, respectively. Whereas collagen is adequately produced in vitro, production of elastin in tissue-engineered constructs is often inadequate when engineering elastic tissues. Therefore, elasticity has to be artificially introduced into tissue-engineered scaffolds. The elasticity of scaffold materials can be attributed to either natural sources, when native elastin or recombinant techniques are used to provide natural polymers, or synthetic sources, when polymers are synthesized. While synthetic elastomers often lack the biocompatibility needed for tissue engineering applications, the production of natural materials in adequate amounts or with proper mechanical strength remains a challenge. However, combining natural and synthetic materials to create hybrid components could overcome these issues. This review explains the synthesis, mechanical properties, and structure of native elastin as well as the theories on how this extracellular matrix component provides elasticity in vivo. Furthermore, current methods, ranging from proteins and synthetic polymers to hybrid structures that are being investigated for providing elasticity to tissue engineering constructs, are comprehensively discussed. STATEMENT OF SIGNIFICANCE Tissue engineered scaffolds are being developed as treatment options for malfunctioning tissues throughout the body. It is essential that the scaffold is a close mimic of the native tissue with regards to both mechanical and biological functionalities. Therefore, the production of elastic scaffolds is of key importance to fabricate tissue engineered scaffolds of the elastic tissues such as heart valves and blood vessels. Combining naturally derived and synthetic materials to reach this goal proves to be an interesting area where a highly tunable material that unites mechanical and biological functionalities can be obtained.
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Affiliation(s)
- Anna M J Coenen
- Aachen-Maastricht Institute for Biobased Materials (AMIBM), Faculty of Science and Engineering, Maastricht University, Brightlands Chemelot Campus, Urmonderbaan 22, 6167 RD Geleen, The Netherlands
| | - Katrien V Bernaerts
- Aachen-Maastricht Institute for Biobased Materials (AMIBM), Faculty of Science and Engineering, Maastricht University, Brightlands Chemelot Campus, Urmonderbaan 22, 6167 RD Geleen, The Netherlands
| | - Jules A W Harings
- Aachen-Maastricht Institute for Biobased Materials (AMIBM), Faculty of Science and Engineering, Maastricht University, Brightlands Chemelot Campus, Urmonderbaan 22, 6167 RD Geleen, The Netherlands
| | - Stefan Jockenhoevel
- Aachen-Maastricht Institute for Biobased Materials (AMIBM), Faculty of Science and Engineering, Maastricht University, Brightlands Chemelot Campus, Urmonderbaan 22, 6167 RD Geleen, The Netherlands; Department of Biohybrid & Medical Textiles (BioTex), AME-Helmholtz Institute for Biomedical Engineering, RWTH Aachen University, Forckenbeckstraβe 55, 52072 Aachen, Germany
| | - Samaneh Ghazanfari
- Aachen-Maastricht Institute for Biobased Materials (AMIBM), Faculty of Science and Engineering, Maastricht University, Brightlands Chemelot Campus, Urmonderbaan 22, 6167 RD Geleen, The Netherlands.
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Abstract
Ligaments serve as compliant connectors between hard tissues. In that role, they function under various load regimes and directions. The 3D structure of ligaments is considered to form as a uniform entity that changes due to function. The periodontal ligament (PDL) connects the tooth to the bone and sustains different types of loads in various directions. Using the PDL as a model, employing a fabricated motorized setup in a microCT, we demonstrate that the fibrous network structure within the PDL is not uniform, even before the tooth becomes functional. Utilizing morphological automated segmentation methods, directionality analysis, as well as second harmonic generation imaging, we find high correlation between blood vessel distribution and fiber density. We also show a structural feature in a form of a dense collar around the neck of the tooth as well as a preferred direction of the fibrous network. Finally, we show that the PDL develops as a nonuniform structure, with an architecture designed to sustain specific types of load in designated areas. Based on these findings, we propose that ligaments in general should be regarded as nonuniform entities, structured already at developmental stages for optimal functioning under variable load regimes.
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23
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Iu J, Santerre JP, Kandel RA. Towards engineering distinct multi-lamellated outer and inner annulus fibrosus tissues. J Orthop Res 2018; 36:1346-1355. [PMID: 29088511 DOI: 10.1002/jor.23793] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Accepted: 10/21/2017] [Indexed: 02/04/2023]
Abstract
The annulus fibrosus (AF) of the intervertebral disc (IVD) has a zonal distribution of phenotypically distinct cells. The outer AF (OAF) cells produce an extracellular matrix (ECM) rich in type I collagen with little proteoglycans, whereas the ECM of the inner AF (IAF) has abundant type II collagen and proteoglycans. The inhomogeneous distribution of the ECM in the AF may reflect the complex mechanical forces that the IVD experiences. A bioengineered AF tissue should recapitulate both the inner and outer zones in order to have proper functionality. The aim of this study is to generate multi-lamellated OAF and IAF tissues with ECM compositions that resemble their zonal origin using polycarbonate urethane (PU) scaffolds. It was observed that supplementation of the media with insulin-transferrin-selenium (ITS) and proline yielded tissues with good cellularity. However, IAF cells accumulated only type I collagen, similar to OAF cells. Addition of dexamethasone and sodium pyruvate induced the accumulation of IAF tissues rich in type II collagen and aggrecan, without altering the accumulation of type I collagen in OAF tissues. Dexamethasone stimulated mitochondrial membrane potential in both tissues in the presence of sodium pyruvate, suggesting a relationship between the mitochondrial aerobic respiratory state and dexamethasone signalling during the in vitro-tissue formation by OAF and IAF cells. Inhibition of the glucocorticoid receptor blocked the stimulation of mitochondrial membrane potentials and type II collagen accumulation. In summary, biologically distinct multi-lamellated OAF and IAF tissues can be generated, which will facilitate advancement towards the goal of engineering a biological IVD replacement. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1346-1355, 2018.
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Affiliation(s)
- Jonathan Iu
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Lunenfeld-Tanenbaum Research Institute, Sinai Health System, 25 Orde Street, Room 5-1013, Toronto, Ontario, M5T 3H7, Canada.,BioEngineering of Skeletal Tissues Team, Pathology and Laboratory Medicine and Lunenfeld Tanenbaum Research Institute, Mount Sinai Hospital, and University of Toronto, 600 University Ave, Ste 6-500, Toronto, Canada
| | - J Paul Santerre
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Lunenfeld-Tanenbaum Research Institute, Sinai Health System, 25 Orde Street, Room 5-1013, Toronto, Ontario, M5T 3H7, Canada
| | - Rita A Kandel
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Lunenfeld-Tanenbaum Research Institute, Sinai Health System, 25 Orde Street, Room 5-1013, Toronto, Ontario, M5T 3H7, Canada.,BioEngineering of Skeletal Tissues Team, Pathology and Laboratory Medicine and Lunenfeld Tanenbaum Research Institute, Mount Sinai Hospital, and University of Toronto, 600 University Ave, Ste 6-500, Toronto, Canada
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New findings confirm the viscoelastic behaviour of the inter-lamellar matrix of the disc annulus fibrosus in radial and circumferential directions of loading. Acta Biomater 2018; 71:411-419. [PMID: 29550440 DOI: 10.1016/j.actbio.2018.03.015] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Revised: 02/13/2018] [Accepted: 03/07/2018] [Indexed: 11/23/2022]
Abstract
While few studies have improved our understanding of composition and organization of elastic fibres in the inter-lamellar matrix (ILM), its clinical relevance is not fully understood. Moreover, no studies have measured the direct tensile and shear failure and viscoelastic properties of the ILM. Therefore, the aim of this study was, for the first time, to measure the viscoelastic and failure properties of the ILM in both the tension and shear directions of loading. Using an ovine model, isolated ILM samples were stretched to 40% of their initial length at three strain rates of 0.1%s-1 (slow), 1%s-1 (medium) and 10%s-1 (fast) and a ramp test to failure was performed at a strain rate of 10%s-1. The findings from this study identified that the stiffness of the ILM was significantly larger at faster strain rates, and energy absorption significantly smaller, compared to slower strain rates, and the viscoelastic and failure properties were not significantly different under tension and shear loading. We found a strain rate dependent response of the ILM during dynamic loading, particularly at the fastest rate. The ILM demonstrated a significantly higher capability for energy absorption at slow strain rates compared to medium and fast strain rates. A significant increase in modulus was found in both loading directions and all strain rates, having a trend of larger modulus in tension and at faster strain rates. The finding of no significant difference in failure properties in both loading directions, was consistent with our previous ultra-structural studies that revealed a well-organized (±45°) elastic fibre orientation in the ILM. The results from this study can be used to develop and validate finite element models of the AF at the tissue scale, as well as providing new strategies for fabricating tissue engineered scaffolds. STATEMENT OF SIGNIFICANCE While few studies have improved our understanding of composition and organization of elastic fibres in the inter-lamellar matrix (ILM) of the annulus in the disc no studies have measured the direct mechanical failure and viscoelastic properties of the ILM. The findings from this study identified that the stiffness of the ILM was significantly larger at faster strain rates, and energy absorption significantly smaller, compared to slower strain rates. The failure properties of the ILM were not significantly different under tension and shear.
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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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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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Zhang M, Yang H, Lu L, Wan X, Zhang J, Zhang H, Liu X, Huang X, Xiao G, Wang M. Matrix replenishing by BMSCs is beneficial for osteoarthritic temporomandibular joint cartilage. Osteoarthritis Cartilage 2017; 25:1551-1562. [PMID: 28532603 DOI: 10.1016/j.joca.2017.05.007] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Revised: 04/24/2017] [Accepted: 05/03/2017] [Indexed: 02/02/2023]
Abstract
OBJECTIVES The present goal was to explore whether matrix replenishment is the primary requirement for osteoarthritic (OA) cartilage. METHODS Cells isolated from the superficial and deep zone cartilage of a pig temporomandibular joint (TMJ) were exposed to fluid flow shear stress (FFSS). Differences in matrix production and cellular differentiation were detected. Unilateral anterior crossbite (UAC) was applied to C57BL/6J female mice. Green fluorescent protein-labeled exogenous bone marrow stromal cells (GFP-BMSCs) were injected weekly into TMJs, starting from 3 weeks of UAC stimulation and continuing for 4-, 8- and 12-weeks. Another GFP-BMSCs injection UAC group stopped receiving injections for 4-weeks after 8-weeks of injections. Assessments were focused on morphological alterations in UAC mouse TMJ cartilage, the expression levels of DAP3, an anoikis marker, CD163, a scavenger receptor family member, and ki67, a proliferation indicator. RESULTS FFSS down-regulated type-II collagen expression but stimulated terminal differentiation in cells isolated from deep zone cartilage. It down-regulated aggrecan expression but up-regulated type I collagen in cells isolated from both superficial and deep zones. UAC caused matrix loss and anoikis and enhanced scavenging activity in deep zone chondrocytes without affecting cell proliferation. Superficial fibrillation was obvious in the late stage. Weekly injections of BMSCs largely restored these changes. The implanted BMSCs expressed a high level of CD163 protein but did not show remarkable cell proliferation. Terminating the supply of exogenous BMSCs reversed the restorative effects. CONCLUSIONS Scavenging the degraded matrix and replenishing the fibrosis-developmental matrix are the primary requirements for the repair of OA cartilage.
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Affiliation(s)
- M Zhang
- State Key Laboratory of Military Stomatology, National Clinical Research Center for Oral Diseases, Shaanxi International Joint Research Center for Oral Diseases, Department of Oral Anatomy and Physiology and TMD, School of Stomatology, The Fourth Military Medical University, 145 Changle West Road, Xi'an, China
| | - H Yang
- State Key Laboratory of Military Stomatology, National Clinical Research Center for Oral Diseases, Shaanxi International Joint Research Center for Oral Diseases, Department of Oral Anatomy and Physiology and TMD, School of Stomatology, The Fourth Military Medical University, 145 Changle West Road, Xi'an, China
| | - L Lu
- State Key Laboratory of Military Stomatology, National Clinical Research Center for Oral Diseases, Shaanxi International Joint Research Center for Oral Diseases, Department of Oral Anatomy and Physiology and TMD, School of Stomatology, The Fourth Military Medical University, 145 Changle West Road, Xi'an, China
| | - X Wan
- State Key Laboratory of Military Stomatology, National Clinical Research Center for Oral Diseases, Shaanxi International Joint Research Center for Oral Diseases, Department of Oral Anatomy and Physiology and TMD, School of Stomatology, The Fourth Military Medical University, 145 Changle West Road, Xi'an, China
| | - J Zhang
- State Key Laboratory of Military Stomatology, National Clinical Research Center for Oral Diseases, Shaanxi International Joint Research Center for Oral Diseases, Department of Oral Anatomy and Physiology and TMD, School of Stomatology, The Fourth Military Medical University, 145 Changle West Road, Xi'an, China
| | - H Zhang
- State Key Laboratory of Military Stomatology, National Clinical Research Center for Oral Diseases, Shaanxi International Joint Research Center for Oral Diseases, Department of Oral Anatomy and Physiology and TMD, School of Stomatology, The Fourth Military Medical University, 145 Changle West Road, Xi'an, China
| | - X Liu
- State Key Laboratory of Military Stomatology, National Clinical Research Center for Oral Diseases, Shaanxi International Joint Research Center for Oral Diseases, Department of Oral Anatomy and Physiology and TMD, School of Stomatology, The Fourth Military Medical University, 145 Changle West Road, Xi'an, China
| | - X Huang
- Department of Biology, The Fourth Military Medical University, 17 Changle West Road, Xi'an, China
| | - G Xiao
- Department of Biology, Shenzhen Key Laboratory of Cell Microenvironment, Southern University of Science and Technology, Shenzhen, China; Department of Biochemistry, Rush University Medical Center, Chicago, IL 60612, USA
| | - M Wang
- State Key Laboratory of Military Stomatology, National Clinical Research Center for Oral Diseases, Shaanxi International Joint Research Center for Oral Diseases, Department of Oral Anatomy and Physiology and TMD, School of Stomatology, The Fourth Military Medical University, 145 Changle West Road, Xi'an, China.
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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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29
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Newell N, Little JP, Christou A, Adams MA, Adam CJ, Masouros SD. Biomechanics of the human intervertebral disc: A review of testing techniques and results. J Mech Behav Biomed Mater 2017; 69:420-434. [PMID: 28262607 DOI: 10.1016/j.jmbbm.2017.01.037] [Citation(s) in RCA: 193] [Impact Index Per Article: 27.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Revised: 01/06/2017] [Accepted: 01/23/2017] [Indexed: 01/08/2023]
Abstract
Many experimental testing techniques have been adopted in order to provide an understanding of the biomechanics of the human intervertebral disc (IVD). The aim of this review article is to amalgamate results from these studies to provide readers with an overview of the studies conducted and their contribution to our current understanding of the biomechanics and function of the IVD. The overview is presented in a way that should prove useful to experimentalists and computational modellers. Mechanical properties of whole IVDs can be assessed conveniently by testing 'motion segments' comprising two vertebrae and the intervening IVD and ligaments. Neural arches should be removed if load-sharing between them and the disc is of no interest, and specimens containing more than two vertebrae are required to study 'adjacent level' effects. Mechanisms of injury (including endplate fracture and disc herniation) have been studied by applying complex loading at physiologically-relevant loading rates, whereas mechanical evaluations of surgical prostheses require slower application of standardised loading protocols. Results can be strongly influenced by the testing environment, preconditioning, loading rate, specimen age and degeneration, and spinal level. Component tissues of the disc (anulus fibrosus, nucleus pulposus, and cartilage endplates) have been studied to determine their material properties, but only the anulus has been thoroughly evaluated. Animal discs can be used as a model of human discs where uniform non-degenerate specimens are required, although differences in scale, age, and anatomy can lead to problems in interpretation.
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Affiliation(s)
- N Newell
- Department of Bioengineering, Imperial College London, London SW7 2AZ, United Kingdom.
| | - J P Little
- Paediatric Spine Research Group, IHBI at Centre for Children's Health Research, Queensland University of Technology, Brisbane, Australia
| | - A Christou
- Department of Bioengineering, Imperial College London, London SW7 2AZ, United Kingdom
| | - M A Adams
- Centre for Applied Anatomy, University of Bristol, Southwell Street, Bristol BS2 8EJ, United Kingdom
| | - C J Adam
- Paediatric Spine Research Group, IHBI at Centre for Children's Health Research, Queensland University of Technology, Brisbane, Australia
| | - S D Masouros
- Department of Bioengineering, Imperial College London, London SW7 2AZ, United Kingdom
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30
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Abstract
The extent of ageing in the musculoskeletal system during the life course affects the quality and length of life. Loss of bone, degraded articular cartilage, and degenerate, narrowed intervertebral discs are primary features of an ageing skeleton, and together they contribute to pain and loss of mobility. This review covers the cellular constituents that make up some key components of the musculoskeletal system and summarizes discussion from the 2015 Aarhus Regenerative Orthopaedic Symposium (AROS) (Regeneration in the Ageing Population) about how each particular cell type alters within the ageing skeletal microenvironment.
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Affiliation(s)
- Sally Roberts
- Spinal Studies and ISTM, Keele University, and Robert Jones and Agnes Hunt Orthopaedic Hospital NHS Foundation Trust, Oswestry, UK
| | - Pauline Colombier
- INSERM U791-LIOAD, Centre Hospitalo-Universitaire (CHU) de Nantes, Nantes, France
| | - Aneka Sowman
- Botnar Research Centre, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Oxford, UK
| | - Claire Mennan
- Spinal Studies and ISTM, Keele University, and Robert Jones and Agnes Hunt Orthopaedic Hospital NHS Foundation Trust, Oswestry, UK
| | - Jan H D Rölfing
- Orthopaedic Research Laboratory and Departments of Orthopaedics, Aarhus and Aalborg University Hospitals, Aarhus, Denmark
| | - Jérôme Guicheux
- INSERM U791-LIOAD, Centre Hospitalo-Universitaire (CHU) de Nantes, Nantes, France
| | - James R Edwards
- Botnar Research Centre, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Oxford, UK,Correspondence:
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31
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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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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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Stewart DM, Monaco LA, Gregory DE. The aging disc: using an ovine model to examine age-related differences in the biomechanical properties of the intralamellar matrix of single lamellae. EUROPEAN SPINE JOURNAL : OFFICIAL PUBLICATION OF THE EUROPEAN SPINE SOCIETY, THE EUROPEAN SPINAL DEFORMITY SOCIETY, AND THE EUROPEAN SECTION OF THE CERVICAL SPINE RESEARCH SOCIETY 2016; 26:259-266. [DOI: 10.1007/s00586-016-4603-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2015] [Revised: 05/03/2016] [Accepted: 05/03/2016] [Indexed: 01/07/2023]
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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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Monaco LA, DeWitte-Orr SJ, Gregory DE. A comparison between porcine, ovine, and bovine intervertebral disc anatomy and single lamella annulus fibrosus tensile properties. J Morphol 2015; 277:244-51. [PMID: 26558749 DOI: 10.1002/jmor.20492] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Revised: 08/14/2015] [Accepted: 10/18/2015] [Indexed: 01/06/2023]
Affiliation(s)
- Lauren A. Monaco
- Department of Biology; Wilfrid Laurier University; 75 University Ave West Waterloo Ontario Canada
| | - Stephanie J. DeWitte-Orr
- Department of Biology; Wilfrid Laurier University; 75 University Ave West Waterloo Ontario Canada
- Department of Health Sciences; Wilfrid Laurier University; 75 University Ave West Waterloo Ontario Canada
| | - Diane E. Gregory
- Department of Health Sciences; Wilfrid Laurier University; 75 University Ave West Waterloo Ontario Canada
- Department of Kinesiology and Physical Education; Wilfrid Laurier University; 75 University Ave West Waterloo Ontario Canada
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Molinos M, Almeida CR, Caldeira J, Cunha C, Gonçalves RM, Barbosa MA. Inflammation in intervertebral disc degeneration and regeneration. J R Soc Interface 2015; 12:20141191. [PMID: 25673296 DOI: 10.1098/rsif.2014.1191] [Citation(s) in RCA: 225] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Intervertebral disc (IVD) degeneration is one of the major causes of low back pain, a problem with a heavy economic burden, which has been increasing in prevalence as populations age. Deeper knowledge of the complex spatial and temporal orchestration of cellular interactions and extracellular matrix remodelling is critical to improve current IVD therapies, which have so far proved unsatisfactory. Inflammation has been correlated with degenerative disc disease but its role in discogenic pain and hernia regression remains controversial. The inflammatory response may be involved in the onset of disease, but it is also crucial in maintaining tissue homeostasis. Furthermore, if properly balanced it may contribute to tissue repair/regeneration as has already been demonstrated in other tissues. In this review, we focus on how inflammation has been associated with IVD degeneration by describing observational and in vitro studies as well as in vivo animal models. Finally, we provide an overview of IVD regenerative therapies that target key inflammatory players.
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Affiliation(s)
- Maria Molinos
- Instituto de Engenharia Biomédica-INEB, Universidade do Porto, Porto, Portugal Instituto de Ciências Biomédicas Abel Salazar-ICBAS, Universidade do Porto, Porto, Portugal
| | - Catarina R Almeida
- Instituto de Engenharia Biomédica-INEB, Universidade do Porto, Porto, Portugal
| | - Joana Caldeira
- Instituto de Engenharia Biomédica-INEB, Universidade do Porto, Porto, Portugal Instituto de Patologia e Imunologia-IPATIMUP, Universidade do Porto, Porto, Portugal
| | - Carla Cunha
- Instituto de Engenharia Biomédica-INEB, Universidade do Porto, Porto, Portugal
| | - Raquel M Gonçalves
- Instituto de Engenharia Biomédica-INEB, Universidade do Porto, Porto, Portugal
| | - Mário A Barbosa
- Instituto de Engenharia Biomédica-INEB, Universidade do Porto, Porto, Portugal Instituto de Ciências Biomédicas Abel Salazar-ICBAS, Universidade do Porto, Porto, Portugal
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37
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ISSLS Prize Winner: A Detailed Examination of the Elastic Network Leads to a New Understanding of Annulus Fibrosus Organization. Spine (Phila Pa 1976) 2015; 40:1149-57. [PMID: 25893352 DOI: 10.1097/brs.0000000000000943] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN Investigation of the elastic network in disc annulus and its function. OBJECTIVE To investigate the involvement of the elastic network in the structural interconnectivity of the annulus and to examine its possible mechanical role. SUMMARY OF BACKGROUND DATA The lamellae of the disc are now known to consist of bundles of collagen fibers organized into compartments. There is strong interconnectivity between adjacent compartments and between adjacent lamellae, possibly aided by a translamellar bridging network, containing blood vessels. An elastic network exists across the disc annulus and is particularly dense between the lamellae, and forms crossing bridges within the lamellae. METHODS Blocks of annulus taken from bovine caudal discs were studied in either their unloaded or radially stretched state then fixed and sectioned, and their structure analyzed optically using immunohistology. RESULTS An elastic network enclosed the collagen compartments, connecting the compartments with each other and with the elastic network of adjacent lamellae, formed an integrated network across the annulus, linking it together. Stretching experiments demonstrated the mechanical interconnectivities of the elastic fibers and the collagen compartments. CONCLUSION The annulus can be viewed as a modular structure organized into compartments of collagen bundles enclosed by an elastic sheath. The elastic network of these sheaths is interconnected mechanically across the entire annulus. This organization is also seen in the modular structure of tendon and muscle. The results provide a new understanding annulus structure and its interconnectivity, and contribute to fundamental structural information relevant to disc tissue engineering and mechanical modeling. LEVEL OF EVIDENCE N/A.
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Han SK, Chen CW, Wierwille J, Chen Y, Hsieh AH. Three dimensional mesoscale analysis of translamellar cross-bridge morphologies in the annulus fibrosus using optical coherence tomography. J Orthop Res 2015; 33:304-11. [PMID: 25564974 PMCID: PMC4346493 DOI: 10.1002/jor.22778] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Accepted: 10/26/2014] [Indexed: 02/04/2023]
Abstract
The defining characteristic of the annulus fibrosus (AF) of the intervertebral disc (IVD) has long been the lamellar structures that consist of highly ordered collagen fibers arranged in alternating oblique angles from one layer to the next. However, a series of recent histologic studies have demonstrated that AF lamellae contain elastin- and type VI collagen-rich secondary "cross-bridge" structures across lamellae. In this study, we use optical coherence tomography (OCT) to elucidate the three-dimensional (3-D) morphologies of these translamellar cross-bridges in AF tissues. Mesoscale volumetric images by OCT revealed a 3-D network of heterogeneously distributed cross-bridges. The results of this study confirm the translamellar cross-bridge is identifiable as a distinguishable structure, which lies in the interbundle space of adjacent lamellae and crisscrosses multiple lamellae in the radial direction. In contrast to previously proposed models extrapolated from 2-D sections, results from this current study show that translamellar cross-bridges exist as a complex, interconnected network. We also found much greater variation in lengths of cross-bridges within the interbundle space of lamellae (0.8-1.4 mm from the current study versus 0.3-0.6 mm from 2-D sections). OCT-based 3-D morphology of translamellar cross-bridge provides novel insight into the AF structure.
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Affiliation(s)
- Sang Kuy Han
- Fischell Department of Bioengineering, University of Maryland, College Park, MD, United States,Advanced Biomedical and Welfare Technology R&BD group, Korea Institute of Industrial Technology, Cheonan-si, Chungcheongnam-do, Korea
| | - Chao-Wei Chen
- Fischell Department of Bioengineering, University of Maryland, College Park, MD, United States
| | - Jerry Wierwille
- Fischell Department of Bioengineering, University of Maryland, College Park, MD, United States
| | - Yu Chen
- Fischell Department of Bioengineering, University of Maryland, College Park, MD, United States
| | - Adam H. Hsieh
- Fischell Department of Bioengineering, University of Maryland, College Park, MD, United States,Department of Orthopaedics, University of Maryland, Baltimore, MD, United States
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Chuah YJ, Lee WC, Wong HK, Kang Y, Hee HT. Three-dimensional development of tensile pre-strained annulus fibrosus cells for tissue regeneration: An in-vitro study. Exp Cell Res 2015; 331:176-182. [DOI: 10.1016/j.yexcr.2014.09.022] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Revised: 09/16/2014] [Accepted: 09/17/2014] [Indexed: 01/13/2023]
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Labus KM, Han SK, Hsieh AH, Puttlitz CM. A computational model to describe the regional interlamellar shear of the annulus fibrosus. J Biomech Eng 2015; 136:051009. [PMID: 24599055 DOI: 10.1115/1.4027061] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2013] [Accepted: 03/06/2014] [Indexed: 11/08/2022]
Abstract
Interlamellar shear may play an important role in the homeostasis and degeneration of the intervertebral disk. Accurately modeling the shear behavior of the interlamellar compartment would enhance the study of its mechanobiology. In this study, physical experiments were utilized to describe interlamellar shear and define a constitutive model, which was implemented into a finite element analysis. Ovine annulus fibrosus (AF) specimens from three locations within the intervertebral disk (lateral, outer anterior, and inner anterior) were subjected to in vitro mechanical shear testing. The local shear stress-stretch relationship was described for the lamellae and across the interlamellar layer of the AF. A hyperelastic constitutive model was defined for interlamellar and lamellar materials at each location tested. The constitutive models were incorporated into a finite element model of a block of AF, which modeled the interlamellar and lamellar layers using a continuum description. The global shear behavior of the AF was compared between the finite element model and physical experiments. The shear moduli at the initial and final regions of the stress-strain curve were greater within the lamellae than across the interlamellar layer. The difference between interlamellar and lamellar shear was greater at the outer anterior AF than at the inner anterior region. The finite element model was shown to accurately predict the global shear behavior or the AF. Future studies incorporating finite element analysis of the interlamellar compartment may be useful for predicting its physiological mechanical behavior to inform the study of its mechanobiology.
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Iu J, Santerre JP, Kandel RA. Inner and Outer Annulus Fibrosus Cells Exhibit Differentiated Phenotypes and Yield Changes in Extracellular Matrix Protein Composition In Vitro on a Polycarbonate Urethane Scaffold. Tissue Eng Part A 2014; 20:3261-9. [DOI: 10.1089/ten.tea.2013.0777] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Jonathan Iu
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Canada
- BioEngineering of Skeletal Tissues Team, Department of Pathology and Laboratory Medicine, Mount Sinai Hospital, University of Toronto, Toronto, Canada
| | - J. Paul Santerre
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Canada
| | - Rita A. Kandel
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Canada
- BioEngineering of Skeletal Tissues Team, Department of Pathology and Laboratory Medicine, Mount Sinai Hospital, University of Toronto, Toronto, Canada
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Papadimitriou N, Thorfve A, Brantsing C, Junevik K, Baranto A, Barreto Henriksson H. Cell Viability and Chondrogenic Differentiation Capability of Human Mesenchymal Stem Cells After Iron Labeling with Iron Sucrose. Stem Cells Dev 2014; 23:2568-80. [DOI: 10.1089/scd.2014.0153] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Affiliation(s)
- Nikolaos Papadimitriou
- Department of Orthopaedics, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
- Department of Orthopaedics, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Anna Thorfve
- Department for Biomaterials, Institute of Clinical Sciences, Sahlgrenska Academy, Gothenburg University of Gothenburg, Gothenburg, Sweden
| | - Camilla Brantsing
- Department of Clinical Chemistry and Transfusion Medicine, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Katarina Junevik
- Department of Clinical Chemistry and Transfusion Medicine, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Adad Baranto
- Department of Orthopaedics, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
- Department of Orthopaedics, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Helena Barreto Henriksson
- Department of Orthopaedics, Institute of Clinical Sciences, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
- Department of Orthopaedics, Sahlgrenska University Hospital, Gothenburg, Sweden
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Merceron C, Mangiavini L, Robling A, Wilson TL, Giaccia AJ, Shapiro IM, Schipani E, Risbud MV. Loss of HIF-1α in the notochord results in cell death and complete disappearance of the nucleus pulposus. PLoS One 2014; 9:e110768. [PMID: 25338007 PMCID: PMC4206488 DOI: 10.1371/journal.pone.0110768] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Accepted: 09/23/2014] [Indexed: 01/08/2023] Open
Abstract
The intervertebral disc (IVD) is one of the largest avascular organs in vertebrates. The nucleus pulposus (NP), a highly hydrated and proteoglycan-enriched tissue, forms the inner portion of the IVD. The NP is surrounded by a multi-lamellar fibrocartilaginous structure, the annulus fibrosus (AF). This structure is covered superior and inferior side by cartilaginous endplates (CEP). The NP is a unique tissue within the IVD as it results from the differentiation of notochordal cells, whereas, AF and CEP derive from the sclerotome. The hypoxia inducible factor-1α (HIF-1α) is expressed in NP cells but its function in NP development and homeostasis is largely unknown. We thus conditionally deleted HIF-1α in notochordal cells and investigated how loss of this transcription factor impacts NP formation and homeostasis at E15.5, birth, 1 and 4 months of age, respectively. Histological analysis, cell lineage studies, and TUNEL assay were performed. Morphologic changes of the mutant NP cells were identified as early as E15.5, followed, postnatally, by the progressive disappearance and replacement of the NP with a novel tissue that resembles fibrocartilage. Notably, lineage studies and TUNEL assay unequivocally proved that NP cells did not transdifferentiate into chondrocyte-like cells but they rather underwent massive cell death, and were completely replaced by a cell population belonging to a lineage distinct from the notochordal one. Finally, to evaluate the functional consequences of HIF-1α deletion in the NP, biomechanical testing of mutant IVD was performed. Loss of the NP in mutant mice significantly reduced the IVD biomechanical properties by decreasing its ability to absorb mechanical stress. These findings are similar to the changes usually observed during human IVD degeneration. Our study thus demonstrates that HIF-1α is essential for NP development and homeostasis, and it raises the intriguing possibility that this transcription factor could be involved in IVD degeneration in humans.
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Affiliation(s)
- Christophe Merceron
- Department of Orthopaedic Surgery, Medical School, University of Michigan, Ann Arbor, Michigan, United States of America
- Inserm, UMRS 791-LIOAD, Centre for Osteoarticular and Dental Tissue Engineering, Group STEP ‘Skeletal Tissue Engineering and Physiopathology’, Nantes, France
- LUNAM, Nantes University, Faculty of Dental Surgery, Nantes, France
| | - Laura Mangiavini
- Department of Orthopaedic Surgery, Medical School, University of Michigan, Ann Arbor, Michigan, United States of America
- Department of Orthopaedic and Traumatology, Milano-Bicocca University, Monza (MB), Italy
| | - Alexander Robling
- School of Medicine, Department of Anatomy and Cell Biology, Indiana University, Indianapolis, Indiana, United States of America
| | - Tremika LeShan Wilson
- Department of Orthopaedic Surgery, Medical School, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Amato J. Giaccia
- School of Medicine, Department of Radiation Oncology, Division of Radiation and Cancer Biology, Stanford University, Stanford, California, United States of America
| | - Irving M. Shapiro
- Department of Orthopaedic Surgery and Graduate Program in Cell and Developmental Biology, Thomas Jefferson University, Philadelphia, Pennsylvania, United States of America
| | - Ernestina Schipani
- Department of Orthopaedic Surgery, Medical School, University of Michigan, Ann Arbor, Michigan, United States of America
- Department of Medicine, Division of Endocrinology, Medical School, University of Michigan, Ann Arbor, Michigan, United States of America
- * E-mail: (MVR); (ES)
| | - Makarand V. Risbud
- Department of Orthopaedic Surgery and Graduate Program in Cell and Developmental Biology, Thomas Jefferson University, Philadelphia, Pennsylvania, United States of America
- * E-mail: (MVR); (ES)
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Binch ALA, Cole AA, Breakwell LM, Michael ALR, Chiverton N, Cross AK, Le Maitre CL. Expression and regulation of neurotrophic and angiogenic factors during human intervertebral disc degeneration. Arthritis Res Ther 2014; 16:416. [PMID: 25209447 PMCID: PMC4177417 DOI: 10.1186/s13075-014-0416-1] [Citation(s) in RCA: 102] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Accepted: 08/01/2014] [Indexed: 12/19/2022] Open
Abstract
Introduction The degenerate intervertebral disc (IVD) becomes innervated by sensory nerve fibres, and vascularised by blood vessels. This study aimed to identify neurotrophins, neuropeptides and angiogenic factors within native IVD tissue and to further investigate whether pro-inflammatory cytokines are involved in the regulation of expression levels within nucleus pulposus (NP) cells, nerve and endothelial cells. Methods Quantitative real-time PCR (qRT-PCR) was performed on 53 human IVDs from 52 individuals to investigate native gene expression of neurotrophic factors and their receptors, neuropeptides and angiogenic factors. The regulation of these factors by cytokines was investigated in NP cells in alginate culture, and nerve and endothelial cells in monolayer using RT-PCR and substance P (SP) protein expression in interleukin-1 (IL-1β) stimulated NP cells. Results Initial investigation on uncultured NP cells identified expression of all neurotrophins by native NP cells, whilst the nerve growth factor (NGF) receptor was only identified in severely degenerate and infiltrated discs, and brain derived neurotrophic factor (BDNF) receptor expressed by more degenerate discs. BDNF expression was significantly increased in infiltrated and degenerate samples. SP and vascular endothelial growth factor (VEGF) were higher in infiltrated samples. In vitro stimulation by IL-1β induced NGF in NP cells. Neurotropin-3 was induced by tumour necrosis factor alpha in human dermal microvascular endothelial cells (HDMECs). SP gene and protein expression was increased in NP cells by IL-1β. Calcitonin gene related peptide was increased in SH-SY5Y cells upon cytokine stimulation. VEGF was induced by IL-1β and interleukin-6 in NP cells, whilst pleiotrophin was decreased by IL-1β. VEGF and pleiotrophin were expressed by SH-SY5Y cells, and VEGF by HDMECs, but were not modulated by cytokines. Conclusions The release of cytokines, in particular IL-1β during IVD degeneration, induced significant increases in NGF and VEGF which could promote neuronal and vascular ingrowth. SP which is released into the matrix could potentially up regulate the production of matrix degrading enzymes and also sensitise nerves, resulting in nociceptive transmission and chronic low back pain. This suggests that IL-1β is a key regulatory cytokine, involved in the up regulation of factors involved in innervation and vascularisation of tissues.
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Wang SZ, Rui YF, Lu J, Wang C. Cell and molecular biology of intervertebral disc degeneration: current understanding and implications for potential therapeutic strategies. Cell Prolif 2014; 47:381-90. [PMID: 25112472 DOI: 10.1111/cpr.12121] [Citation(s) in RCA: 98] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2014] [Accepted: 05/09/2014] [Indexed: 12/25/2022] Open
Abstract
Intervertebral disc degeneration (IDD) is a chronic, complex process associated with low back pain; mechanisms of its occurrence have not yet been fully elucidated. Its process is not only accompanied by morphological changes, but also by systematic changes in its histological and biochemical properties. Many cellular and molecular mechanisms have been reported to be related with IDD and to reverse degenerative trends, abnormal conditions of the living cells and altered cell phenotypes would need to be restored. Promising biological therapeutic strategies still rely on injection of active substances, gene therapy and cell transplantation. With advanced study of tissue engineering protocols based on cell therapy, combined use of seeding cells, bio-active substances and bio-compatible materials, are promising for IDD regeneration. Recently reported progenitor cells within discs themselves also hold prospects for future IDD studies. This article describes the background of IDD, current understanding and implications of potential therapeutic strategies.
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Affiliation(s)
- S Z Wang
- Department of Orthopaedics, Zhongda Hospital, Medical School of Southeast University, Nanjing, Jiangsu, 210009, China
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Gregory DE, Bae WC, Sah RL, Masuda K. Disc degeneration reduces the delamination strength of the annulus fibrosus in the rabbit annular disc puncture model. Spine J 2014; 14:1265-71. [PMID: 24594442 PMCID: PMC4063999 DOI: 10.1016/j.spinee.2013.07.489] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2012] [Revised: 06/01/2013] [Accepted: 07/25/2013] [Indexed: 02/03/2023]
Abstract
BACKGROUND CONTEXT Degenerative disc disease is a common pathologic disorder accompanied by both structural and biochemical changes. Changes in stress distribution across the disc can lead to annulus fibrosus (AF) damage that can affect the strength and integrity of the disc. Given that some present degeneration therapies incorporate biological regrowth of the nucleus pulposus (NP), it is crucial that the AF remains capable of containing this newly grown material. PURPOSE To examine the resistance of AF to delamination using an adhesive peel test in experimentally degenerated rabbit discs. STUDY DESIGN Experimentally induced disc degeneration; excised AF tissue study. METHODS Disc degeneration was induced in eight New Zealand white rabbits by annular puncture; four additional rabbits served as controls. In experimental rabbits, an 18-gauge needle was inserted into the anterolateral AF region of levels L2-L3 and L4-L5, and disc height was monitored by X-ray. Animals were sacrificed at 4 and 12 weeks postsurgery and magnetic resonance images and X-rays were taken. Four discs were excised from the experimental animals; two punctured (L2-L3 and L4-L5) and two controls (L3-L4 and L6-L7). The same four discs were also excised from the age-matched control animals and served as nonpunctured control discs. To determine resistance to delamination, AF samples were dissected from each disc and subjected to a mechanical peel test at 0.5 mm/s. RESULTS Magnetic resonance imaging and X-ray images confirmed dehydration of the NP and reduced disc height, similar to that found in clinical degeneration. Resistance to delamination was significantly lower in punctured/degenerated discs compared with both the nonpunctured discs from the same animal (27% lower) and the nonpunctured control discs (30% lower) (p=.024). CONCLUSIONS The findings of this study suggest that degeneration increases the potential for delamination between AF layers. Given this substantial change to the integrity of the AF after degeneration, clinical treatments should not only target rehydration or regrowth of the NP, but should also target repair and strengthening of the AF to confine the NP.
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Affiliation(s)
- Diane E. Gregory
- Department of Kinesiology and Physical Education, Wilfrid Laurier University, Waterloo, Canada
| | - Won C. Bae
- Department of Radiology, University of California San Diego, USA
| | - Robert L. Sah
- Department of Bioengineering, University of California San Diego, USA
,Department of Orthopaedic Surgery, University of California San Diego, USA
| | - Koichi Masuda
- Department of Radiology, University of California San Diego, 200 West Arbor Drive, San Diego, CA, 92103, USA.
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Green EM, Mansfield JC, Bell JS, Winlove CP. The structure and micromechanics of elastic tissue. Interface Focus 2014; 4:20130058. [PMID: 24748954 PMCID: PMC3982448 DOI: 10.1098/rsfs.2013.0058] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Elastin is a major component of tissues such as lung and blood vessels, and endows them with the long-range elasticity necessary for their physiological functions. Recent research has revealed the complexity of these elastin structures and drawn attention to the existence of extensive networks of fine elastin fibres in tissues such as articular cartilage and the intervertebral disc. Nonlinear microscopy, allowing the visualization of these structures in living tissues, is informing analysis of their mechanical properties. Elastic fibres are complex in composition and structure containing, in addition to elastin, an array of microfibrillar proteins, principally fibrillin. Raman microspectrometry and X-ray scattering have provided new insights into the mechanisms of elasticity of the individual component proteins at the molecular and fibrillar levels, but more remains to be done in understanding their mechanical interactions in composite matrices. Elastic tissue is one of the most stable components of the extracellular matrix, but impaired mechanical function is associated with ageing and diseases such as atherosclerosis and diabetes. Efforts to understand these associations through studying the effects of processes such as calcium and lipid binding and glycation on the mechanical properties of elastin preparations in vitro have produced a confusing picture, and further efforts are required to determine the molecular basis of such effects.
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Affiliation(s)
| | | | | | - C. Peter Winlove
- Department of Physics, College of Engineering Mathematics and Physical Science, University of Exeter, Stocker Road, Exeter EX4 4QL, UK
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Colombier P, Clouet J, Hamel O, Lescaudron L, Guicheux J. The lumbar intervertebral disc: From embryonic development to degeneration. Joint Bone Spine 2014; 81:125-9. [DOI: 10.1016/j.jbspin.2013.07.012] [Citation(s) in RCA: 96] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Accepted: 07/16/2013] [Indexed: 01/07/2023]
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Sharifi S, Bulstra SK, Grijpma DW, Kuijer R. Treatment of the degenerated intervertebral disc; closure, repair and regeneration of the annulus fibrosus. J Tissue Eng Regen Med 2014; 9:1120-32. [PMID: 24616324 DOI: 10.1002/term.1866] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2013] [Revised: 09/19/2013] [Accepted: 11/25/2013] [Indexed: 12/25/2022]
Abstract
Degeneration of the intervertebral disc (IVD) and disc herniation are two causes of low back pain. The aetiology of these disorders is unknown, but tissue weakening, which primarily occurs due to inherited genetic factors, ageing, nutritional compromise and loading history, is the basic factor causing disc degeneration. Symptomatic disc herniation mainly causes radicular pain. Current treatments of intervertebral disc degeneration and low back pain are based on alleviating the symptoms and comprise administration of painkillers or surgical methods such as spinal fusion. None of these methods is completely successful. Current research focuses on regeneration of the IVD and particularly on regeneration of the nucleus pulposus. Less attention has been directed to the repair or regeneration of the annulus fibrosus, although this is the key to successful nucleus pulposus, and therewith IVD, repair. This review focuses on the importance of restoring the function of the annulus fibrosus, as well as on the repair, replacement or regeneration of the annulus fibrosus in combination with restoration of the function of the nucleus pulposus, to treat low back pain.
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Affiliation(s)
- Shahriar Sharifi
- University of Groningen, University Medical Center Groningen, W. J. Kolff Institute, Department of Biomedical Engineering, Groningen, The Netherlands
- MIRA Institute for Biomedical Technology and Technical Medicine, Department of Biomaterials Science and Technology, University of Twente, Enschede, The Netherlands
| | - Sjoerd K Bulstra
- University of Groningen, University Medical Center Groningen, Department of Orthopaedic Surgery, Groningen, The Netherlands
| | - Dirk W Grijpma
- University of Groningen, University Medical Center Groningen, W. J. Kolff Institute, Department of Biomedical Engineering, Groningen, The Netherlands
- MIRA Institute for Biomedical Technology and Technical Medicine, Department of Biomaterials Science and Technology, University of Twente, Enschede, The Netherlands
| | - Roel Kuijer
- University of Groningen, University Medical Center Groningen, W. J. Kolff Institute, Department of Biomedical Engineering, Groningen, The Netherlands
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Kang R, Svend Le DQ, Li H, Lysdahl H, Chen M, Besenbacher F, Bünger C. Engineered three-dimensional nanofibrous multi-lamellar structure for annulus fibrosus repair. J Mater Chem B 2013; 1:5462-5468. [DOI: 10.1039/c3tb20562b] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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