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Wang Z, Chen X, Chen N, Yan H, Wu K, Li J, Ru Q, Deng R, Liu X, Kang R. Mechanical Factors Regulate Annulus Fibrosus (AF) Injury Repair and Remodeling: A Review. ACS Biomater Sci Eng 2024; 10:219-233. [PMID: 38149967 DOI: 10.1021/acsbiomaterials.3c01091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2023]
Abstract
Low back pain is a common chronic disease that can severely affect the patient's work and daily life. The breakdown of spinal mechanical homeostasis caused by intervertebral disc (IVD) degeneration is a leading cause of low back pain. Annulus fibrosus (AF), as the outer layer structure of the IVD, is often the first affected part. AF injury caused by consistent stress overload will further accelerate IVD degeneration. Therefore, regulating AF injury repair and remodeling should be the primary goal of the IVD repair strategy. Mechanical stimulation has been shown to promote AF regeneration and repair, but most studies only focus on the effect of single stress on AF, and lack realistic models and methods that can mimic the actual mechanical environment of AF. In this article, we review the effects of different types of stress stimulation on AF injury repair and remodeling, suggest possible beneficial load combinations, and explore the underlying molecular mechanisms. It will provide the theoretical basis for designing better tissue engineering therapy using mechanical factors to regulate AF injury repair and remodeling in the future.
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Affiliation(s)
- Zihan Wang
- Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, Jiangsu Province 210028, P.R. China
| | - Xin Chen
- Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, Jiangsu Province 210028, P.R. China
| | - Nan Chen
- Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, Jiangsu Province 210028, P.R. China
| | - Hongjie Yan
- Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, Jiangsu Province 210028, P.R. China
| | - Ke Wu
- Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, Jiangsu Province 210028, P.R. China
| | - Jitao Li
- School of Physics and Telecommunications Engineering, Zhoukou Normal University, Zhoukou, Henan Province 466001, P.R. China
| | - Qingyuan Ru
- Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, Jiangsu Province 210028, P.R. China
| | - Rongrong Deng
- Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, Jiangsu Province 210028, P.R. China
| | - Xin Liu
- Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, Jiangsu Province 210028, P.R. China
| | - Ran Kang
- Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, Jiangsu Province 210028, P.R. China
- Department of Orthopedics, Nanjing Lishui Hospital of Traditional Chinese Medicine, Nanjing, Jiangsu Province 210028, P.R. China
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Takeoka Y, Kanda Y, Kang JD, Mizuno S. Regenerative Capability of Human Nucleus Pulposus Cells in Degenerated Disc Under Hydrostatic Pressure Mimicking Physiologically Relevant Intradiscal Pressure In Vitro. Spine (Phila Pa 1976) 2023; 48:728-736. [PMID: 36856558 PMCID: PMC10118243 DOI: 10.1097/brs.0000000000004530] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Accepted: 10/26/2022] [Indexed: 03/02/2023]
Abstract
STUDY DESIGN Isolated human nucleus pulposus (hNP) cells from the degenerated intervertebral disc (IVD) were incubated under hydrostatic pressure (HP) and evaluated for regenerative potential. OBJECTIVES To characterize metabolic turnover in hNP cells isolated from degenerated IVDs classified by Pfirrmann grade under physiologically relevant HP at high osmolality in vitro. SUMMARY OF BACKGROUND DATA We demonstrated that bovine caudal nucleus pulposus cells isolated from healthy cows produced more extracellular matrix under cyclic HP followed by constant pressure (mimicking physiological intradiscal pressure in humans) than under no pressure in vitro. We assessed the effects of pressure on human degenerated cells isolated under the same regimen of pressure used for bovine cells. MATERIALS AND METHODS hNP cells isolated from discarded tissue classified as Pfirrmann grade 2 to 3 (n = 13: age, 46.7 ± 14.0) and grade 4 (n = 13: age, 53.0 ± 11.5) were incubated under cyclic HP at 0.2 to 0.7 MPa, 0.5 Hz for 2 days followed by constant pressure at 0.3 MPa for 1 day, repeated twice over 6 days. The gene expression and immunohistology of matrix molecules and catabolic and anticatabolic proteins were evaluated. RESULTS Aggrecan and collagen type II expression were significantly more upregulated under HP in grades 2 to 3 than in grade 4 tissues (both, P < 0.01). Linear regression analysis showed a positive correlation between matrix metalloproteinase 13 and tissue inhibitor for metalloproteinase 2 expression in grades 2 to 3, whereas a negative correlation was found in grade 4 ( P < 0.05). Immunohistological staining revealed the activation of a mechanoreceptor, transient receptor potential vanilloid 4, under HP. CONCLUSIONS Resident cells in mild-moderate degenerated discs classified as Pfirrmann grade 2 to 3 have the potential to promote extracellular matrix production and maintain adequate cell viability under physiological spinal loading. RELEVANCE This study explored the potential of degenerated remnant nucleus pulposus cells under a physiological environment, possibly leading to establishing strategies for IVD regeneration.
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Hydrostatic Pressure Modulates Intervertebral Disc Cell Survival and Extracellular Matrix Homeostasis via Regulating Hippo-YAP/TAZ Pathway. Stem Cells Int 2021; 2021:5626487. [PMID: 34221023 PMCID: PMC8221882 DOI: 10.1155/2021/5626487] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Accepted: 06/05/2021] [Indexed: 01/14/2023] Open
Abstract
Established studies proved that hydrostatic pressure had multiple effects on the biological behavior of the intervertebral disc (IVD). However, the conclusions of the previous studies were inconsistent, due to the difference in hydrostatic loading devices and observing methods used in these studies. The current study is aimed at investigating the role of dynamic hydrostatic pressure in regulating biological behavior of the notochordal nucleus pulposus (NP) and fibrocartilaginous inner annulus fibrosus (AF) and its possible mechanism using our novel self-developed hydrostatic pressure bioreactor. The differences in the biological behavior of the rabbit IVD tissues under different degree of hydrostatic pressure were evaluated via histological analysis. Results revealed that low-loading dynamic hydrostatic pressure was beneficial for cell survival and extracellular matrix (ECM) homeostasis in notochordal NP and fibrocartilaginous inner AF via upregulating N-cadherin (N-CDH) and integrin β1. In comparison, high-magnitude dynamic hydrostatic pressure aggravated the breakdown of ECM homeostasis in NP and inner AF via enhancing the Hippo-YAP/TAZ pathway-mediated cell apoptosis. Moreover, inner AF exhibited greater tolerance to physiological medium-loading degree of hydrostatic pressure than notochordal NP. The potential mechanism was related to the differential expression of mechanosensing factors in notochordal NP and fibrocartilaginous inner AF, which affects the fate of the cells under hydrostatic pressure. Our findings may provide a better understanding of the regulatory role of hydrostatic pressure on the cellular fate commitment and matrix metabolism of the IVD and more substantial evidence for using hydrostatic pressure bioreactor in exploring the IVD degeneration mechanism as well as regeneration strategies.
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Takeoka Y, Paladugu P, Kang JD, Mizuno S. Augmented Chondroitin Sulfate Proteoglycan Has Therapeutic Potential for Intervertebral Disc Degeneration by Stimulating Anabolic Turnover in Bovine Nucleus Pulposus Cells under Changes in Hydrostatic Pressure. Int J Mol Sci 2021; 22:ijms22116015. [PMID: 34199496 PMCID: PMC8199579 DOI: 10.3390/ijms22116015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 05/10/2021] [Accepted: 05/28/2021] [Indexed: 01/17/2023] Open
Abstract
Nucleus pulposus (NP) cells are exposed to changes in hydrostatic pressure (HP) and osmotic pressure within the intervertebral disc. We focused on main disc matrix components, chondroitin sulfate proteoglycan (CSPG) and hyaluronan (HA) to elucidate the capability of augmented CSPG to enhance the anabolism of bovine NP (bNP) cells under repetitive changes in HP at high osmolality. Aggrecan expression with CSPG in the absence of HP was significantly upregulated compared to the no-material control (phosphate buffer saline) under no HP at 3 days, and aggrecan expression with CSPG under HP was significantly higher than the control with HA under HP at 12 days. Collagen type I expression under no HP was significantly lower with CSPG than in controls at 3 days. Although matrix metalloproteinase 13 expression under HP was downregulated compared to no HP, it was significantly greater with HA than the control and CSPG, even under HP. Immunohistology revealed the involvement of mechanoreceptor of transient receptor potential vanilloid-4 activation under HP, suggesting an HP transduction mechanism. Addition of CSPG had anabolic and anti-fibrotic effects on bNP cells during the early culture period under no HP; furthermore, it showed synergy with dynamic HP to increase bNP-cell anabolism at later time points.
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McMorran JG, Gregory DE. The Influence of Axial Compression on the Cellular and Mechanical Function of Spinal Tissues; Emphasis on the Nucleus Pulposus and Annulus Fibrosus: A Review. J Biomech Eng 2021; 143:050802. [PMID: 33454730 DOI: 10.1115/1.4049749] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Indexed: 11/08/2022]
Abstract
In light of the correlation between chronic back pain and intervertebral disc (IVD) degeneration, this literature review seeks to illustrate the importance of the hydraulic response across the nucleus pulposus (NP)-annulus fibrosus (AF) interface, by synthesizing current information regarding injurious biomechanics of the spine, stemming from axial compression. Damage to vertebrae, endplates (EPs), the NP, and the AF, can all arise from axial compression, depending on the segment's posture, the manner in which it is loaded, and the physiological state of tissue. Therefore, this movement pattern was selected to illustrate the importance of the bracing effect of a pressurized NP on the AF, and how injuries interrupting support to the AF may contribute to IVD degeneration.
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Affiliation(s)
- John G McMorran
- Department of Kinesiology and Physical Education, Wilfrid Laurier University, 75 University Avenue West, Waterloo, ON N2 L 3C5
| | - Diane E Gregory
- Department of Kinesiology and Physical Education, Wilfrid Laurier University, 75 University Avenue West, Waterloo, ON N2 L 3C5; Department of Health Sciences, Wilfrid Laurier University, 75 University Avenue West, Waterloo, ON N2 L 3C5
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Matyas JR, Klein C, Ponjevic D, Duncan NA, Kawchuk GN. Repetitive in vivo manual loading of the spine elicits cellular responses in porcine annuli fibrosi. PLoS One 2021; 16:e0248104. [PMID: 33755684 PMCID: PMC7987143 DOI: 10.1371/journal.pone.0248104] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 02/21/2021] [Indexed: 11/19/2022] Open
Abstract
Back pain and intervertebral disc degeneration are prevalent, costly, and widely treated by manual therapies, yet the underlying causes of these diseases are indeterminate as are the scientific bases for such treatments. The present studies characterize the effects of repetitive in vivo manual loads on porcine intervertebral disc cell metabolism using RNA deep sequencing. A single session of repetitive manual loading applied to the lumbar spine induced both up- and down-regulation of a variety of genes transcribed by cells in the ventral annuli fibrosi. The effect of manual therapy at the level of loading was greater than at a level distant to the applied load. Gene ontology and molecular pathway analyses categorized biological, molecular, and cellular functions influenced by repetitive manual loading, with over-representation of membrane, transmembrane, and pericellular activities. Weighted Gene Co-expression Network Analysis discerned enrichment in genes in pathways of inflammation and skeletogenesis. The present studies support previous findings of intervertebral disc cell mechanotransduction, and are the first to report comprehensively on the repertoire of gene targets influenced by mechanical loads associated with manual therapy interventions. The present study defines the cellular response of repeated, low-amplitude loads on normal healthy annuli fibrosi and lays the foundation for future work defining how healthy and diseased intervertebral discs respond to single or low-frequency manual loads typical of those applied clinically.
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Affiliation(s)
- John Robert Matyas
- Department of Comparative Biology & Experimental Medicine, McCaig Institute of Bone and Joint Health, University of Calgary Faculty of Veterinary Medicine, Calgary, Alberta, Canada
- * E-mail:
| | - Claudia Klein
- Department of Clinical and Veterinary Clinical Sciences, Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Dragana Ponjevic
- Department of Comparative Biology & Experimental Medicine, McCaig Institute of Bone and Joint Health, University of Calgary Faculty of Veterinary Medicine, Calgary, Alberta, Canada
| | - Neil A. Duncan
- Department of Civil Engineering, Schulich School of Engineering, University of Calgary, Calgary, Alberta, Canada
| | - Gregory N. Kawchuk
- Department of Physical Therapy, Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, Alberta, Canada
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Hodder E, Guppy F, Covill D, Bush P. The effect of hydrostatic pressure on proteoglycan production in articular cartilage in vitro: a meta-analysis. Osteoarthritis Cartilage 2020; 28:1007-1019. [PMID: 32445666 DOI: 10.1016/j.joca.2020.03.021] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 03/03/2020] [Accepted: 03/26/2020] [Indexed: 02/02/2023]
Abstract
OBJECTIVE In previous research the use of hydrostatic pressure (HP) has been applied to enhance the formation of engineered cartilage, through the up-regulation of proteoglycan synthesis by mechanotransduction. However, the HP stimulation approach has been shown to vary between studies with a wide disparity in results, including anabolic, catabolic and non-responsive outcomes. To this end, a meta-analysis of HP publications using 3D cultured chondrocytes was performed to elucidate the key experiment factors involved in achieving a mechanotransducive response. DESIGN The effects of different HP regimes on proteoglycan production were investigated based on the following factors: static vs dynamic application, pressure magnitude, and experiment duration. Meta-analysis was performed on raw data taken from 11 publications which employed either aggrecan gene expression analysis or dimethyl methylene blue colorimetric assay. The measure of effect was calculated based on mean difference using a random effects model. RESULTS Analysis revealed that a significant anabolic response was most likely achieved when the following factors were employed; a static HP application, a magnitude within the mid-high physiological range of cartilage (≤5-10 MPa) and a study duration of ≥2 weeks. CONCLUSIONS Thus, we propose that the selection of HP experiment factors can have a significant influence on engineered cartilage development, and that the results of this meta-analysis can be used as a basis for the planning of future HP experiments.
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Affiliation(s)
- E Hodder
- School of Computing, Engineering and Mathematics, University of Brighton, Cockcroft Building, Lewes Road, Brighton, BN2 4GJ, UK; School of Pharmacy and Biomolecular Sciences, University of Brighton, Huxley Building, Lewes Road, Brighton, BN2 4GJ, UK.
| | - F Guppy
- School of Pharmacy and Biomolecular Sciences, University of Brighton, Huxley Building, Lewes Road, Brighton, BN2 4GJ, UK; Centre for Stress and Age-related Disease, University of Brighton, Huxley Building, Lewes Road, Brighton, BN2 4GJ, UK
| | - D Covill
- School of Computing, Engineering and Mathematics, University of Brighton, Cockcroft Building, Lewes Road, Brighton, BN2 4GJ, UK
| | - P Bush
- School of Pharmacy and Biomolecular Sciences, University of Brighton, Huxley Building, Lewes Road, Brighton, BN2 4GJ, UK
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Saggese T, Thambyah A, Wade K, McGlashan SR. Differential Response of Bovine Mature Nucleus Pulposus and Notochordal Cells to Hydrostatic Pressure and Glucose Restriction. Cartilage 2020; 11:221-233. [PMID: 29808709 PMCID: PMC7097982 DOI: 10.1177/1947603518775795] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
OBJECTIVE The nucleus pulposus of the human intervertebral disc contains 2 cell types: notochordal (NC) and mature nucleus pulposus (MNP) cells. NC cell loss is associated with disc degeneration and this process may be initiated by mechanical stress and/or nutrient deprivation. This study aimed to investigate the functional responses of NC and MNP cells to hydrostatic pressures and glucose restriction. DESIGN Bovine MNP and NC cells were cultured in 3-dimensional alginate beads under low (0.4-0.8 MPa) and high (1.6-2.4 MPa) dynamic pressure for 24 hours. Cells were cultured in either physiological (5.5 mM) glucose media or glucose-restriction (0.55 mM) media. Finally, the combined effect of glucose restriction and high pressure was examined. RESULTS Cell viability and notochordal phenotypic markers were not significantly altered in response to pressure or glucose restriction. MNP cells responded to low pressure with an increase in glycosaminoglycan (GAG) production while high pressure significantly decreased ACAN gene expression compared with atmospheric controls. NC cells showed no response in matrix gene expression or GAG production with either loading regime. Glucose restriction decreased NC cell TIMP-1 expression but had no effect on MNP cells. The combination of glucose restriction and high pressure only affected MNP cell gene expression, with decreased ACAN, Col2α1, and ADAMTS-5 expression. CONCLUSION This study shows that NC cells are more resistant to acute mechanical stresses than MNP cells and provides a strong rationale for future studies to further our understanding the role of NC cells within the disc, and the effects of long-term exposure to physical stresses.
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Affiliation(s)
- Taryn Saggese
- Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Ashvin Thambyah
- Department of Chemical and Materials Engineering, Faculty of Engineering, University of Auckland, Auckland, New Zealand
| | - Kelly Wade
- Department of Chemical and Materials Engineering, Faculty of Engineering, University of Auckland, Auckland, New Zealand
| | - Susan Read McGlashan
- Department of Anatomy and Medical Imaging, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
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Design of a Lumbar Interspinous Fixation Device for Minimally Invasive Surgery and Spine Motion Stabilization. J Med Biol Eng 2019. [DOI: 10.1007/s40846-019-00485-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Shah BS, Chahine NO. Dynamic Hydrostatic Pressure Regulates Nucleus Pulposus Phenotypic Expression and Metabolism in a Cell Density-Dependent Manner. J Biomech Eng 2019; 140:2666887. [PMID: 29247254 DOI: 10.1115/1.4038758] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Indexed: 11/08/2022]
Abstract
Dynamic hydrostatic pressure (HP) loading can modulate nucleus pulposus (NP) cell metabolism, extracellular matrix (ECM) composition, and induce transformation of notochordal NP cells into mature phenotype. However, the effects of varying cell density and dynamic HP magnitude on NP phenotype and metabolism are unknown. This study examined the effects of physiological magnitudes of HP loading applied to bovine NP cells encapsulated within three-dimensional (3D) alginate beads. Study 1: seeding density (1 M/mL versus 4 M/mL) was evaluated in unloaded and loaded (0.1 MPa, 0.1 Hz) conditions. Study 2: loading magnitude (0, 0.1, and 0.6 MPa) applied at 0.1 Hz to 1 M/mL for 7 days was evaluated. Study 1: 4 M/mL cell density had significantly lower adenosine triphosphate (ATP), glycosaminoglycan (GAG) and collagen content, and increased lactate dehydrogenase (LDH). HP loading significantly increased ATP levels, and expression of aggrecan, collagen I, keratin-19, and N-cadherin in HP loaded versus unloaded groups. Study 2: aggrecan expression increased in a dose dependent manner with HP magnitude, whereas N-cadherin and keratin-19 expression were greatest in low HP loading compared to unloaded. Overall, the findings of the current study indicate that cell seeding density within a 3D construct is a critical variable influencing the mechanobiological response of NP cells to HP loading. NP mechanobiology and phenotypic expression was also found to be dependent on the magnitude of HP loading. These findings suggest that HP loading and culture conditions of NP cells may require complex optimization for engineering an NP replacement tissue.
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Affiliation(s)
- Bhranti S Shah
- Department of Orthopedic Surgery, Columbia University, New York, NY 10032
| | - Nadeen O Chahine
- Department of Orthopedic Surgery, Columbia University, 650 West 168th Street, 14-1408E, New York, NY 10032.,Department of Biomedical Engineering, Columbia University, New York, NY 10032 e-mail:
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Effect of needle diameter, type and volume of contrast agent on intervertebral disc degeneration in rats with discography. 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; 28:1014-1022. [PMID: 30864063 DOI: 10.1007/s00586-019-05927-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 01/17/2019] [Accepted: 02/21/2019] [Indexed: 01/08/2023]
Abstract
PURPOSE Discography can increase disc degeneration, but the influence of different discography variables on the degeneration of discs has not been reported. The aim of this study was to investigate the effects of discography variables of needle diameter, type of contrast agent and volume of contrast agent on disc degeneration. METHODS Three separate experiments examined needle diameter, and type and volume of contrast agent. Coccygeal discs (Co7-10) adult male rats were used. X-rays were used to detect the disc height degeneration index at 1, 2 and 4 weeks after the procedure. MRI was used to study the changes in the disc structure and the signal intensity of IVD 2 and 4 weeks after the procedure. Disc water content and histology were measured at 4 weeks after the procedure. RESULTS A 21-g needle significantly increased disc degeneration when compared with the 30-g needle as detected by X-ray, MRI, disc water content and histology (P < 0.05). Two microlitres of iodine significantly decreased the disc MRI signal and water content at 4 weeks compared with the same volume of normal saline (P < 0.05). Three microlitres of iodine significantly increased disc degeneration when compared with 2 µl iodine, as detected by X-ray, MRI, disc water content and histology at 4 weeks (P < 0.05). CONCLUSION To reduce disc degeneration after discography, it may be best to choose a smaller needle size, minimize the use of contrast agent and use non-ionic contrast agents with osmotic pressure similar to the intervertebral disc. These slides can be retrieved under Electronic Supplementary Material.
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Abstract
Mechanical loading of the intervertebral disc (IVD) initiates cell-mediated remodeling events that contribute to disc degeneration. Cells of the IVD, nucleus pulposus (NP) and anulus fibrosus (AF), will exhibit various responses to different mechanical stimuli which appear to be highly dependent on loading type, magnitude, duration, and anatomic zone of cell origin. Cells of the NP, the innermost region of the disc, exhibit an anabolic response to low-moderate magnitudes of static compression, osmotic pressure, or hydrostatic pressure, while higher magnitudes promote a catabolic response marked by increased protease expression and activity. Cells of the outer AF are responsive to physical forces in a manner that depends on frequency and magnitude, as are cells of the NP, though they experience different forces, deformations, pressure, and osmotic pressure in vivo. Much remains to be understood of the mechanotransduction pathways that regulate IVD cell responses to loading, including responses to specific stimuli and also differences among cell types. There is evidence that cytoskeletal remodeling and receptor-mediated signaling are important mechanotransduction events that can regulate downstream effects like gene expression and posttranslational biosynthesis, all of which may influence phenotype and bioactivity. These and other mechanotransduction events will be regulated by known and to-be-discovered cell-matrix and cell-cell interactions, and depend on composition of extracellular matrix ligands for cell interaction, matrix stiffness, and the phenotype of the cells themselves. Here, we present a review of the current knowledge of the role of mechanical stimuli and the impact upon the cellular response to loading and changes that occur with aging and degeneration of the IVD.
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Affiliation(s)
- Bailey V Fearing
- Department of Biomedical Engineering & Orthopedic Surgery, Washington University in St. Louis, St. Louis, Missouri
| | - Paula A Hernandez
- Department of Orthopaedic Surgery, University of Texas Southwestern, Dallas, Texas
| | - Lori A Setton
- Department of Biomedical Engineering & Orthopedic Surgery, Washington University in St. Louis, St. Louis, Missouri
| | - Nadeen O Chahine
- Department of Orthopedic Surgery & Biomedical Engineering, Columbia University, New York, New York
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13
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Hodson NW, Patel S, Richardson SM, Hoyland JA, Gilbert HTJ. Degenerate intervertebral disc-like pH induces a catabolic mechanoresponse in human nucleus pulposus cells. JOR Spine 2018; 1:e1004. [PMID: 31463436 PMCID: PMC6711490 DOI: 10.1002/jsp2.1004] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Revised: 01/22/2018] [Accepted: 02/12/2018] [Indexed: 11/07/2022] Open
Abstract
Mechanical stimulation is known to influence intervertebral disc (IVD) cell behavior and function, but the effect on disc cells is routinely considered in isolation from other microenvironmental factors. Acidic pH has been shown to be a prominent and detrimental microenvironmental factor present in degenerate IVDs, but its influence on the human disc cell mechanoresponse has never been studied. We investigated the response of agarose-encapsulated human nucleus pulposus (NP) cells to 0.004 MPa, 1.0 Hz and 1 hour of compression (Flexcell FX4000 Compression System) under pH conditions representative of nondegenerate (pH 7.1) and degenerate (pH 6.5) IVDs. Cell viability, extracellular matrix production, and expression of anabolic/anti-catabolic and catabolic genes were assessed. We report that preculture of NP cells in agarose gels was required in order for cells to be mechanoresponsive, and this correlated with increased type VI collagen, α5β1 integrin, and fibronectin expression. Furthermore, the matrix homeostatic response observed at pH 7.1 (representative of nondegenerate IVDs; increased aggrecan [AGC], tissue inhibitor of metalloproteinases-1 [TIMP1], matrix metalloproteinase-3 [MMP3], a disintegrin and metalloproteinase with thrombospondin motif-5 [ADAMTS5] gene expression) was RGD-integrin dependent, whereas only MMP3 remained mechanoresponsive at pH 6.5, and this was independent of RGD-integrins. Our findings suggest differential mechanotransduction pathways operating for specific genes, with RGD-integrin dependent AGC expression, but not RGD-independent MMP3 expression, inhibited at pH representative of degenerate IVDs (pH 6.5), which could contribute to the catabolic phenotype observed during IVD degeneration. CLINICAL SIGNIFICANCE Characterizing the influence of the mechanical and chemical intervertebral disc microenvironment on disc cells, particularly in disc degeneration, could help develop future therapeutic strategies for the treatment of discogenic back pain.
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Affiliation(s)
- Nathan W. Hodson
- Division of Cell Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology, Medicine and HealthUniversity of ManchesterManchesterUK
| | - Sonal Patel
- Division of Cell Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology, Medicine and HealthUniversity of ManchesterManchesterUK
| | - Stephen M. Richardson
- Division of Cell Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology, Medicine and HealthUniversity of ManchesterManchesterUK
| | - Judith A. Hoyland
- Division of Cell Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology, Medicine and HealthUniversity of ManchesterManchesterUK
- NIHR Manchester Musculoskeletal Biomedical Research Unit, Central Manchester NHS Foundation TrustManchester Academic Health Science CentreManchesterUK
| | - Hamish T. J. Gilbert
- Division of Cell Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology, Medicine and HealthUniversity of ManchesterManchesterUK
- Wellcome Trust Centre for Cell‐Matrix Research, Division of Cell Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology, Medicine and HealthUniversity of ManchesterManchesterUK
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14
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Zvicer J, Obradovic B. Bioreactors with hydrostatic pressures imitating physiological environments in intervertebral discs. J Tissue Eng Regen Med 2017; 12:529-545. [PMID: 28763577 DOI: 10.1002/term.2533] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Revised: 06/27/2017] [Accepted: 07/27/2017] [Indexed: 12/28/2022]
Abstract
Intervertebral discs are normally exposed to a variety of loads and stresses but hydrostatic pressure (HP) could be the main biosignal for chondrogenic cell differentiation and maintenance of this tissue. Although there are simple approaches to intermittently expose cell cultures to HP in separate material testing devices, utilization of biomimetic bioreactors aiming to provide in vitro conditions mimicking those found in vivo, attracts special attention. However, design of such bioreactors is complex due to the requirement of high HP magnitudes (up to 3 MPa) applied in different regimes mimicking pressures arising in intervertebral disc during normal daily activities. Furthermore, efficient mass transfer has to be facilitated to cells within 3D scaffolds, and the engineering challenges include avoidance or removal of gas bubbles in the culture medium before pressurization as well as selection of appropriate, biocompatible construction materials and maintenance of sterility during cultivation. Here, we review approaches to induce HP in 2D and 3D cell cultures categorized into 5 groups: (I) discontinuous systems with direct pressurization of the cultivation medium by a piston, (II) discontinuous systems with indirect pressurization by a compression fluid, (III) continuous systems with direct pressurization of the cultivation medium, static culture, (IV) continuous systems with culture perfusion, and (V) systems applying HP in conjunction with other physical signals. Although the complexity is increasing as additional features are added to the systems, the need to understand HP effects on cells and tissues in a physiologically relevant, yet precisely controlled, environment together with current technological advancements are leading towards innovative bioreactor solutions.
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Affiliation(s)
- Jovana Zvicer
- Faculty of Technology and Metallurgy, University of Belgrade, Belgrade, Serbia
| | - Bojana Obradovic
- Faculty of Technology and Metallurgy, University of Belgrade, Belgrade, Serbia
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Li JK, Nie L, Zhao YP, Zhang YQ, Wang X, Wang SS, Liu Y, Zhao H, Cheng L. IL-17 mediates inflammatory reactions via p38/c-Fos and JNK/c-Jun activation in an AP-1-dependent manner in human nucleus pulposus cells. J Transl Med 2016; 14:77. [PMID: 26988982 PMCID: PMC4794827 DOI: 10.1186/s12967-016-0833-9] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Accepted: 03/07/2016] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Low back pain and sciatica caused by intervertebral disc (IVD) disease are associated with inflammatory responses. The cytokine interleukin 17 (IL-17) is elevated in herniated and degenerated IVD tissues and acts as a regulator of disc inflammation. The objective of this study was to investigate the involvement of IL-17A in IVD inflammatory response and to explore the mechanisms underlying this response. METHODS Cells were isolated from nucleus pulposus (NP) tissues collected from patients undergoing surgeries for IVD degeneration. The concentrations of COX2 and PGE2, as well as of select proteins involved in the mitogen-activated protein kinase (MAPK)/activating protein-1 (AP-1) pathway, were quantified in NP cells after exposure to IL-17 with or without pretreatment with MAPK or AP-1 inhibitors. RESULTS Our results showed that IL-17A increased COX2 expression and PGE2 production via the activation of MAPKs, including p38 kinase and Jun N-terminal kinase (JNK). Moreover, IL-17A-induced COX2 and PGE2 production was shown to rely on p38/c-Fos and JNK/c-Jun activation in an AP-1-dependent manner. CONCLUSION In summary, our results indicate that IL-17A enhances COX2 expression and PGE2 production via the p38/c-Fos and JNK/c-Jun signalling pathways in NP cells to mediate IVD inflammation.
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Affiliation(s)
- Jing-kun Li
- />Department of Orthopaedic Surgery, Qilu Hospital, Shandong University, Jinan, 250012 Shandong People’s Republic of China
| | - Lin Nie
- />Department of Orthopaedic Surgery, Qilu Hospital, Shandong University, Jinan, 250012 Shandong People’s Republic of China
| | - Yun-peng Zhao
- />Department of Orthopaedic Surgery, Qilu Hospital, Shandong University, Jinan, 250012 Shandong People’s Republic of China
| | - Yuan-qiang Zhang
- />Department of Orthopaedic Surgery, Qilu Hospital, Shandong University, Jinan, 250012 Shandong People’s Republic of China
| | - Xiaoqing Wang
- />Department of Orthopaedic Surgery, Shanghai Ninth People’s Hospital, Shanghai, 200011 People’s Republic of China
| | - Shuai-shuai Wang
- />Department of Orthopaedic Surgery, Qilu Hospital, Shandong University, Jinan, 250012 Shandong People’s Republic of China
| | - Yi Liu
- />Department of Orthopaedic Surgery, Qilu Hospital, Shandong University, Jinan, 250012 Shandong People’s Republic of China
| | - Hua Zhao
- />Department of Orthopaedic Surgery, Qilu Hospital, Shandong University, Jinan, 250012 Shandong People’s Republic of China
| | - Lei Cheng
- />Department of Orthopaedic Surgery, Qilu Hospital, Shandong University, Jinan, 250012 Shandong People’s Republic of China
- />Qilu Hospital Shandong University, No.107, Wen Hua Xi Road, Jinan, 250012 Shandong People’s Republic of China
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Barthelemy VMP, van Rijsbergen MM, Wilson W, Huyghe JM, van Rietbergen B, Ito K. A computational spinal motion segment model incorporating a matrix composition-based model of the intervertebral disc. J Mech Behav Biomed Mater 2015; 54:194-204. [PMID: 26469631 DOI: 10.1016/j.jmbbm.2015.09.028] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Revised: 09/10/2015] [Accepted: 09/23/2015] [Indexed: 01/08/2023]
Abstract
The extracellular matrix of the intervertebral disc is subjected to changes with age and degeneration, affecting the biomechanical behaviour of the spine. In this study, a finite element model of a generic spinal motion segment that links spinal biomechanics and intervertebral disc biochemical composition was developed. The local mechanical properties of the tissue were described by the local matrix composition, i.e. fixed charge density, amount of water and collagen and their organisation. The constitutive properties of the biochemical constituents were determined by fitting numerical responses to experimental measurements derived from literature. This general multi-scale model of the disc provides the possibility to evaluate the relation between local disc biochemical composition and spinal biomechanics.
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Affiliation(s)
- V M P Barthelemy
- Orthopaedic Biomechanics, Department of Biomedical Engineering, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | - M M van Rijsbergen
- Orthopaedic Biomechanics, Department of Biomedical Engineering, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | - W Wilson
- Orthopaedic Biomechanics, Department of Biomedical Engineering, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | - J M Huyghe
- Orthopaedic Biomechanics, Department of Biomedical Engineering, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | - B van Rietbergen
- Orthopaedic Biomechanics, Department of Biomedical Engineering, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands
| | - K Ito
- Orthopaedic Biomechanics, Department of Biomedical Engineering, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands.
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Zhao H, Ni CF, Huang J, Zhao SM, Gu WW, Jiang H, Chen L, Tan TS. Effects of bone cement on intervertebral disc degeneration. Exp Ther Med 2014; 7:963-969. [PMID: 24669259 PMCID: PMC3965156 DOI: 10.3892/etm.2014.1531] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2013] [Accepted: 01/09/2014] [Indexed: 12/03/2022] Open
Abstract
Percutaneous vertebroplasty (PVP) is popular for the treatment of intractable pain due to vertebral collapse from various lesions, intervertebral disk leakage of cement is a frequent complication. The aim of this study was to determine whether bone cement causes disc degeneration, and to evaluate the degree of intervertebral disc degeneration (IDD) according to the time period following cement injection, and the type and volume of cement injected. Sixteen dogs were randomly divided into two groups that were sacrificed at 12 or 24 weeks following cement injection. Five intervertebral discs in each dog were studied, including one control untreated disc and four discs randomly injected with polymethylmethacrylate (PMMA) or calcium phosphate cement (CPC) in two quantities. Radiographic and magnetic resonance imaging (MRI) studies were performed prior to animal sacrifice. T2-weighted mid-sagittal images of the discs were qualitatively analyzed for evidence of degeneration by calculating the MRI index, and all harvested discs were studied histopathologically. IDD was not evident in control discs. Univariate analysis revealed significant differences in the MRI index and the histological grade of disc degeneration in terms of the time period following cement injection, as well as the type and volume of cement injected. Result indicate that direct contact with PMMA and CPC can lead to IDD. However, IDD induced by PMMA was more severe than that induced by CPC. The extent of IDD was found to correlate with the time period post-cement injection and the volume of cement injected into the disc. PMMA and CPC may lead to intervertebral disc degeneration. Intervertebral disc degeneration induced by PMMA is more serious than that of CPC. The degree of intervertebral disc degeneration is correlative to the time after operation and the doses of bone cement.
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Affiliation(s)
- Hui Zhao
- Department of Interventional Radiology, The Hospital Affiliated of Nantong University, Nantong, Jiangsu 226001, P.R. China
| | - Cai-Fang Ni
- Department of Interventional Radiology, The First Affiliated Hospital of Soochow University, Nantong, Jiangsu 215006, P.R. China
| | - Jian Huang
- Department of Interventional Radiology, The Hospital Affiliated of Nantong University, Nantong, Jiangsu 226001, P.R. China
| | - Su-Ming Zhao
- Department of Interventional Radiology, The Hospital Affiliated of Nantong University, Nantong, Jiangsu 226001, P.R. China
| | - Wei-Wei Gu
- Department of Interventional Radiology, The Hospital Affiliated of Nantong University, Nantong, Jiangsu 226001, P.R. China
| | - Hao Jiang
- Department of Interventional Radiology, The Hospital Affiliated of Nantong University, Nantong, Jiangsu 226001, P.R. China
| | - Long Chen
- Department of Interventional Radiology, The First Affiliated Hospital of Soochow University, Nantong, Jiangsu 215006, P.R. China
| | - Tian-Si Tan
- Department of Orthopedics, The First Affiliated Hospital of Soochow University, Nantong, Jiangsu 215006, P.R. China
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Gilbert HTJ, Nagra NS, Freemont AJ, Millward-Sadler SJ, Hoyland JA. Integrin - dependent mechanotransduction in mechanically stimulated human annulus fibrosus cells: evidence for an alternative mechanotransduction pathway operating with degeneration. PLoS One 2013; 8:e72994. [PMID: 24039840 PMCID: PMC3764176 DOI: 10.1371/journal.pone.0072994] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Accepted: 07/23/2013] [Indexed: 12/11/2022] Open
Abstract
Intervertebral disc (IVD) cells derived from degenerate tissue respond aberrantly to mechanical stimuli, potentially due to altered mechanotransduction pathways. Elucidation of the altered, or alternative, mechanotransduction pathways operating with degeneration could yield novel targets for the treatment of IVD disease. Our aim here was to investigate the involvement of RGD-recognising integrins and associated signalling molecules in the response to cyclic tensile strain (CTS) of human annulus fibrosus (AF) cells derived from non-degenerate and degenerate IVDs. AF cells from non-degenerate and degenerate human IVDs were cyclically strained with and without function blocking RGD – peptides with 10% strain, 1.0 Hz for 20 minutes using a Flexercell® strain device. QRT-PCR and Western blotting were performed to analyse gene expression of type I collagen and ADAMTS -4, and phosphorylation of focal adhesion kinase (FAK), respectively. The response to 1.0 Hz CTS differed between the two groups of AF cells, with decreased ADAMTS -4 gene expression and decreased type I collagen gene expression post load in AF cells derived from non-degenerate and degenerate IVDs, respectively. Pre-treatment of non-degenerate AF cells with RGD peptides prevented the CTS-induced decrease in ADAMTS -4 gene expression, but caused an increase in expression at 24 hours, a response not observed in degenerate AF cells where RGD pre-treatment failed to inhibit the mechano-response. In addition, FAK phosphorylation increased in CTS stimulated AF cells derived from non-degenerate, but not degenerate IVDs, with RGD pre-treatment inhibiting the CTS – dependent increase in phosphorylated FAK. Our findings suggest that RGD -integrins are involved in the 1.0 Hz CTS – induced mechano-response observed in AF cells derived from non-degenerate, but not degenerate IVDs. This data supports our previous work, suggesting an alternative mechanotransduction pathway may be operating in degenerate AF cells.
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Affiliation(s)
- Hamish T. J. Gilbert
- Centre for Regenerative Medicine, Institute of Inflammation and Repair, Faculty of Medical and Human Sciences, The University of Manchester, Manchester, United Kingdom
| | - Navraj S. Nagra
- Centre for Regenerative Medicine, Institute of Inflammation and Repair, Faculty of Medical and Human Sciences, The University of Manchester, Manchester, United Kingdom
| | - Anthony J. Freemont
- Centre for Regenerative Medicine, Institute of Inflammation and Repair, Faculty of Medical and Human Sciences, The University of Manchester, Manchester, United Kingdom
| | - Sarah J. Millward-Sadler
- Centre for Regenerative Medicine, Institute of Inflammation and Repair, Faculty of Medical and Human Sciences, The University of Manchester, Manchester, United Kingdom
| | - Judith A. Hoyland
- Centre for Regenerative Medicine, Institute of Inflammation and Repair, Faculty of Medical and Human Sciences, The University of Manchester, Manchester, United Kingdom
- * E-mail:
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Yokoyama K, Hiyama A, Arai F, Nukaga T, Sakai D, Mochida J. C-Fos regulation by the MAPK and PKC pathways in intervertebral disc cells. PLoS One 2013; 8:e73210. [PMID: 24023832 PMCID: PMC3759433 DOI: 10.1371/journal.pone.0073210] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Accepted: 07/17/2013] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND The gene encoding c-fos is an important factor in the pathogenesis of joint disease in patients with osteoarthritis. However, it is unknown whether the signal mechanism of c-fos acts in intervertebral disc (IVD) cells. We investigated whether c-fos is activated in relation to mitogen-activated protein kinases (MAPKs) and the protein kinase C (PKC) pathway in nucleus pulposus (NP) cells. METHODOLOGY/RESULTS Reverse transcription-polymerase chain reaction and western blotting analyses were used to measure the expression of c-fos in rat IVD cells. Transfections were performed to determine the effects of c-fos on target gene activity. The effect of c-fos protein expression was examined in transfection experiments and in a 3- (4,5-dimethylthiazol-2-yl) -2,5-diphenyltetrazolium bromide cell viability assay. Phorbol 12-myristate 13-acetate (PMA), the most commonly used phorbol ester, binds to and activates protein kinase C (PKC), causing a wide range of effects in cells and tissues. PMA induced the expression of c-fos gene transcription and protein expression, and led to activation of the MAPK pathways in NP cells. The c-fos promoter was suppressed completely in the presence of the MAPK inhibitor PD98059, an inhibitor of the MEK/ERK kinase cascade, but not in the presence of SKF86002, SB202190, or SP600125. The effects of the PKC pathway on the transcriptional activity of the c-fos were evaluated. PKCγ and PKCδ suppressed the promoter activity of c-fos. Treatment with c-fos inhibited aggrecan and Col2 promoter activities and the expression of these genes in NP cells. CONCLUSIONS This study demonstrated, for the first time, that the MAPK and PKC pathways had opposing effects on the regulation of c-fos in NP cells. Thus, the expression of c-fos can be suppressed in the extracellular matrix of NP cells.
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Affiliation(s)
- Katsuya Yokoyama
- Department of Orthopaedic Surgery, Surgical Science, Tokai University School of Medicine, Kanagawa, Japan
- Research Center for Regenerative Medicine, Tokai University School of Medicine, Kanagawa, Japan
| | - Akihiko Hiyama
- Department of Orthopaedic Surgery, Surgical Science, Tokai University School of Medicine, Kanagawa, Japan
- Research Center for Regenerative Medicine, Tokai University School of Medicine, Kanagawa, Japan
- * E-mail:
| | - Fumiyuki Arai
- Department of Orthopaedic Surgery, Surgical Science, Tokai University School of Medicine, Kanagawa, Japan
- Research Center for Regenerative Medicine, Tokai University School of Medicine, Kanagawa, Japan
| | - Tadashi Nukaga
- Department of Orthopaedic Surgery, Surgical Science, Tokai University School of Medicine, Kanagawa, Japan
- Research Center for Regenerative Medicine, Tokai University School of Medicine, Kanagawa, Japan
| | - Daisuke Sakai
- Department of Orthopaedic Surgery, Surgical Science, Tokai University School of Medicine, Kanagawa, Japan
- Research Center for Regenerative Medicine, Tokai University School of Medicine, Kanagawa, Japan
| | - Joji Mochida
- Department of Orthopaedic Surgery, Surgical Science, Tokai University School of Medicine, Kanagawa, Japan
- Research Center for Regenerative Medicine, Tokai University School of Medicine, Kanagawa, Japan
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20
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He B, Wang YH, Yang J, Peng FL, Li F. Normal and degenerated rabbit nucleus pulposus cells in in vitro cultures: A biological comparison. ACTA ACUST UNITED AC 2013; 33:228-233. [PMID: 23592135 DOI: 10.1007/s11596-013-1102-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2012] [Indexed: 12/30/2022]
Abstract
This study examined the biological characteristics of normal and degenerated rabbit nucleus pulposus (NP) cells in vitro in order to provide seed cells for intervertebral disc (IVD) tissue engineering. A total of 8 adult New Zealand white rabbits underwent annulus puncture to establish models of intervertebral disc degeneration (IDD). Four weeks later, normal and degenerated NP cells were obtained. Cell morphology was observed by light and electron microscopy. Cell viability was measured by MTT assay. Cell cycle and expression of extracellular matrix (ECM)-related genes (aggrecan and type II collagen) were determined by using flow cytometry and RT-PCR respectively. The growth curve of normal NP cells showed that the cells at passage 4 tended to slowly grow on the fifth day of culture. The density of normal NP cells at passages 5 to 7 was significantly less than that of the first-passage cells 2 or 3 days after seeding (P<0.05). The degenerated NP cells at passage 3 showed slow growth at 4th day. After 5 passages, the degenerated NP cells assumed stagnant growth and the growth seemed to stop at passage 7. The MTT assay revealed that for both normal and degenerated NP cells, the absorbance (A) value at passages 4-7 was obviously decreased as compared with that at passage 1 (P<0.05). Cell cycle analysis showed that the proportion of normal NP cells at Gl phase was 65.4%±3.5%, significantly lower than that of degenerated NP cells at the same cell cycle phase with the value being 77.6%±4.8%. The degenerated NP cells were predominantly arrested at G1 phase and failed to enter S phase. The expression of type II collagen and aggrecan was significantly decreased with passaging. It was concluded that normal NP cells possessed good viability and proliferative capacity by the third passage, and they could secrete large amounts of ECM within this period. The normal NP cells may serve as seed cells for IVD tissue engineering.
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Affiliation(s)
- Bin He
- Department of Orthopedics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
- Department of Orthopedics, the First Affiliated Hospital of Medical College of Shihezi University, Shihezi, 832008, China
| | - Yu-Huan Wang
- Medical College of Shihezi University, Shihezi, 832002, China
| | - Jian Yang
- Department of Orthopedics, the First Affiliated Hospital of Medical College of Shihezi University, Shihezi, 832008, China
| | - Fang-Liang Peng
- Department of Orthopedics, the First Affiliated Hospital of Medical College of Shihezi University, Shihezi, 832008, China
| | - Feng Li
- Department of Orthopedics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China.
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Neidlinger-Wilke C, Mietsch A, Rinkler C, Wilke HJ, Ignatius A, Urban J. Interactions of environmental conditions and mechanical loads have influence on matrix turnover by nucleus pulposus cells. J Orthop Res 2012; 30:112-21. [PMID: 21674606 DOI: 10.1002/jor.21481] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2011] [Accepted: 05/26/2011] [Indexed: 02/04/2023]
Abstract
Disc degeneration is associated with several changes in the physicochemical environment of intervertebral disc cells. Nucleus pulposus (NP) cells in the center of degenerated discs are exposed to decreased glucose supply, osmolarity, pH, and oxygen levels. To understand the complexity of these interactions on a cellular level, we designed standardized experiments in which we compared responses to these environmental factors under normal levels with those seen under two different degrees of disc degeneration. We hypothesized that these changes in environmental stimuli influence gene expression of matrix proteins and matrix degrading enzymes and alter their responses to cyclic hydrostatic pressure (HP). Our results suggest that a simulation of degenerative conditions influences the degradation of disc matrix through impairing matrix formation and accelerating matrix resorption via up- or down-regulation of the respective target genes. The greatest effects were seen for decreases in glucose concentration and pH. Low oxygen had little influence. HP had little direct effect but appeared to counteract matrix degradation by reducing or inverting some of the adverse effects of other stimuli. For ongoing in vitro studies, interactions between mechanical stimuli and factors in the physicochemical environment should not be ignored as these could markedly influence results.
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Seol D, Choe H, Zheng H, Jang K, Ramakrishnan PS, Lim TH, Martin JA. Selection of reference genes for normalization of quantitative real-time PCR in organ culture of the rat and rabbit intervertebral disc. BMC Res Notes 2011; 4:162. [PMID: 21615931 PMCID: PMC3118343 DOI: 10.1186/1756-0500-4-162] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2010] [Accepted: 05/26/2011] [Indexed: 11/22/2022] Open
Abstract
Background The accuracy of quantitative real-time RT-PCR (qRT-PCR) is often influenced by experimental artifacts, resulting in erroneous expression profiles of target genes. The practice of employing normalization using a reference gene significantly improves reliability and its applicability to molecular biology. However, selection of an ideal reference gene(s) is of critical importance to discern meaningful results. The aim of this study was to evaluate the stability of seven potential reference genes (Actb, GAPDH, 18S rRNA, CycA, Hprt1, Ywhaz, and Pgk1) and identify most stable gene(s) for application in tissue culture research using the rat and rabbit intervertebral disc (IVD). Findings In vitro, four genes (Hprt1, CycA, GAPDH, and 18S rRNA) in rat IVD tissue and five genes (CycA, Hprt1, Actb, Pgk1, and Ywhaz) in rabbit IVD tissue were determined as most stable for up to 14 days in culture. Pair-wise variation analysis indicated that combination of Hprt1 and CycA in rat and the combination of Hprt1, CycA, and Actb in rabbit may most stable reference gene candidates for IVD tissue culture. Conclusions Our results indicate that Hprt1 and CycA are the most stable reference gene candidates for rat and rabbit IVD culture studies. In rabbit IVD, Actb could be an additional gene employed in conjunction with Hprt1 and CycA. Selection of optimal reference gene candidate(s) should be a pertinent exercise before employment of PCR outcome measures for biomedical research.
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Affiliation(s)
- Dongrim Seol
- Department of Orthopedics and Rehabilitation, University of Iowa, 1182 ML, Iowa city, IA 52242, USA.
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Chan SCW, Ferguson SJ, Gantenbein-Ritter B. The effects of dynamic loading on the intervertebral disc. 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 2011; 20:1796-812. [PMID: 21541667 DOI: 10.1007/s00586-011-1827-1] [Citation(s) in RCA: 154] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2010] [Revised: 03/21/2011] [Accepted: 04/20/2011] [Indexed: 01/08/2023]
Abstract
Loading is important to maintain the balance of matrix turnover in the intervertebral disc (IVD). Daily cyclic diurnal assists in the transport of large soluble factors across the IVD and its surrounding circulation and applies direct and indirect stimulus to disc cells. Acute mechanical injury and accumulated overloading, however, could induce disc degeneration. Recently, there is more information available on how cyclic loading, especially axial compression and hydrostatic pressure, affects IVD cell biology. This review summarises recent studies on the response of the IVD and stem cells to applied cyclic compression and hydrostatic pressure. These studies investigate the possible role of loading in the initiation and progression of disc degeneration as well as quantifying a physiological loading condition for the study of disc degeneration biological therapy. Subsequently, a possible physiological/beneficial loading range is proposed. This physiological/beneficial loading could provide insight into how to design loading regimes in specific system for the testing of various biological therapies such as cell therapy, chemical therapy or tissue engineering constructs to achieve a better final outcome. In addition, the parameter space of 'physiological' loading may also be an important factor for the differentiation of stem cells towards most ideally 'discogenic' cells for tissue engineering purpose.
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Affiliation(s)
- Samantha C W Chan
- ARTORG Center for Biomedical Engineering, Spine Research Center, Institute for Surgical Technology and Biomechanics, University of Bern, Stauffacherstrasse 78, 3014 Bern, Switzerland
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Gilbert HTJ, Hoyland JA, Freemont AJ, Millward-Sadler SJ. The involvement of interleukin-1 and interleukin-4 in the response of human annulus fibrosus cells to cyclic tensile strain: an altered mechanotransduction pathway with degeneration. Arthritis Res Ther 2011; 13:R8. [PMID: 21276216 PMCID: PMC3241352 DOI: 10.1186/ar3229] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2010] [Revised: 12/01/2010] [Accepted: 01/28/2011] [Indexed: 01/30/2023] Open
Abstract
Introduction Recent evidence suggests that intervertebral disc (IVD) cells derived from degenerative tissue are unable to respond to physiologically relevant mechanical stimuli in the 'normal' anabolic manner, but instead respond by increasing matrix catabolism. Understanding the nature of the biological processes which allow disc cells to sense and respond to mechanical stimuli (a process termed 'mechanotransduction') is important to ascertain whether these signalling pathways differ with disease. The aim here was to investigate the involvement of interleukin (IL)-1 and IL-4 in the response of annulus fibrosus (AF) cells derived from nondegenerative and degenerative tissue to cyclic tensile strain to determine whether cytokine involvement differed with IVD degeneration. Methods AF cells were isolated from nondegenerative and degenerative human IVDs, expanded in monolayers and cyclically strained in the presence or absence of the cytokine inhibitors IL-1 receptor antagonist (IL-1Ra) or IL-4 receptor antibody (IL-4RAb) with 10% strain at 1.0 Hz for 20 minutes using a Flexcell strain device. Total RNA was extracted from the cells at time points of baseline control and 1 or 24 hours poststimulation. Quantitative real-time polymerase chain reaction was used to analyse the gene expression of matrix proteins (aggrecan and type I collagen) and enzymes (matrix metalloproteinase 3 (MMP3) and a disintegrin and metalloproteinase with a thrombospondin type 1 motif 4 (ADAMTS4)). Results Expression of catabolic genes (MMP3 and ADAMTS4) decreased in AF cells derived from nondegenerative tissue in response to 1.0-Hz stimulation, and this decrease in gene expression was inhibited or increased following pretreatment of cells with IL-1Ra or IL-4RAb respectively. Treatment of AF cells derived from degenerative tissue with an identical stimulus (1.0-Hz) resulted in reduced anabolic gene expression (aggrecan and type I collagen), with IL-1Ra or IL-4RAb pretreatment having no effect. Conclusions Both IL-1 and IL-4 are involved in the response of AF cells derived from nondegenerative tissue to 1.0-Hz cyclic tensile strain. Interestingly, the altered response observed at 1.0-Hz in AF cells from degenerative tissue appears to be independent of either cytokine, suggesting an alternative mechanotransduction pathway in operation.
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Affiliation(s)
- Hamish T J Gilbert
- School of Biomedicine, Faculty of Medical and Human Sciences, University of Manchester, Manchester M139PL, UK
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Gilbert HTJ, Hoyland JA, Millward-Sadler SJ. The response of human anulus fibrosus cells to cyclic tensile strain is frequency-dependent and altered with disc degeneration. ACTA ACUST UNITED AC 2010; 62:3385-94. [PMID: 20617521 DOI: 10.1002/art.27643] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
OBJECTIVE Mechanical loads are important for homeostasis of the intervertebral disc (IVD) cell matrix, with physiologic and nonphysiologic loads leading to matrix anabolism and catabolism, respectively. Previous investigations into the effects of load on disc cells have predominantly used animal models, with the limited number of human studies focusing primarily on nucleus pulposus cells. The aim of this study was to examine the effect of cyclic tensile strain (CTS) on human anulus fibrosus (AF) cells to ascertain whether the response was frequency-dependent and to compare AF cells derived from nondegenerated and degenerated tissue samples. METHODS AF cells were isolated from nondegenerated and degenerated human IVDs, expanded in monolayer, and cyclically strained for 20 minutes, applying 10% strain at a frequency of 1.0 Hz or 0.33 Hz with the use of a Flexcell strain device. Total RNA was extracted from the cells at baseline (control) and at 1, 3, and 24 hours following application of CTS. Real-time quantitative polymerase chain reaction was used to analyze gene expression of matrix proteins (aggrecan, type I collagen, and type II collagen) and enzymes (matrix metalloproteinases [MMPs] 3, 9, 13, and ADAMTS-4). RESULTS The expression of catabolic genes (MMP-3 and ADAMTS-4) in AF cells derived from nondegenerated tissue decreased in response to 1.0 Hz of CTS, whereas changing the frequency to 0.33 Hz resulted in a shift toward matrix catabolism. Application of 1.0 Hz of CTS reduced anabolic gene expression (aggrecan and type I collagen) in AF cells derived from degenerated tissue, with 0.33 Hz of CTS resulting in increased catabolic gene expression. CONCLUSION The response of human AF cells to CTS is frequency-dependent and is altered by degeneration.
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Rinkler C, Heuer F, Pedro MT, Mauer UM, Ignatius A, Neidlinger-Wilke C. Influence of low glucose supply on the regulation of gene expression by nucleus pulposus cells and their responsiveness to mechanical loading. J Neurosurg Spine 2010; 13:535-42. [DOI: 10.3171/2010.4.spine09713] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Object
Environmental alterations resulting in a decrease in the nutrient supply have been associated with intervertebral disc (IVD) degeneration, particularly of the nucleus pulposus (NP). The goal of the present study was to examine the hypothesis that glucose deprivation alters the metabolism of NP cells and their responsiveness to mechanical loading. A possible interaction of glucose supply and hydrostatic pressure (HP) with gene expression by NP cells has not been investigated.
Methods
The influence of glucose supply (physiological concentration: 5 mM, reduction: 0 or 0.5 mM) and cyclic HP loading (2.5 MPa, 0.1 Hz, 30 minutes) on bovine and human NP cell matrix turnover was analyzed by quantitative real-time reverse transcriptase–polymerase chain reaction. Glucose-dependent effects on cell viability were determined by trypan blue exclusion. A glycosaminoglycan (GAG) assay was performed to determine nutritional effects on the protein level.
Results
Glucose reduction resulted in significant downregulations (p < 0.05) of aggrecan, collagen-I, and collagen-II gene expression by bovine NP cells. Exemplary human donors also displayed a similar trend for aggrecan and collagen-II, whereas matrix metalloproteinases (MMPs) tended to be upregulated under glucose deprivation. After HP loading, human NP cells showed individual upregulations of collagen-I and collagen-II expression, while MMP expression tended to be downregulated under glucose reduction relative to a normal glucose supply. Cell viability decreased with glucose deprivation. The GAG content was similar in all groups at Day 1, whereas at Day 3 there was a significant increase under physiological conditions.
Conclusions
Glucose deprivation strongly affected NP cell metabolism. The effects of an altered glucose supply on gene expression were more pronounced than the mechanically induced effects. Data in this study demonstrate that the glucose environment is more critical for disc cell metabolism than mechanical loads. In individual human donors, however, adequate mechanical stimuli might have a beneficial effect on matrix turnover during IVD degeneration.
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Affiliation(s)
- Christina Rinkler
- 1Institute of Orthopaedic Research and Biomechanics, Centre for Musculoskeletal Research
| | - Frank Heuer
- 1Institute of Orthopaedic Research and Biomechanics, Centre for Musculoskeletal Research
| | | | - Uwe Max Mauer
- 3Department of Neurosurgery, German Armed Forces Hospital, Ulm, Germany
| | - Anita Ignatius
- 1Institute of Orthopaedic Research and Biomechanics, Centre for Musculoskeletal Research
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Plochocki JH, Ward CV, Smith DE. Evaluation of the chondral modeling theory using fe-simulation and numeric shape optimization. J Anat 2010; 214:768-77. [PMID: 19438771 DOI: 10.1111/j.1469-7580.2009.01070.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
The chondral modeling theory proposes that hydrostatic pressure within articular cartilage regulates joint size, shape, and congruence through regional variations in rates of tissue proliferation. The purpose of this study is to develop a computational model using a nonlinear two-dimensional finite element analysis in conjunction with numeric shape optimization to evaluate the chondral modeling theory. The model employed in this analysis is generated from an MR image of the medial portion of the tibiofemoral joint in a subadult male. Stress-regulated morphological changes are simulated until skeletal maturity and evaluated against the chondral modeling theory. The computed results are found to support the chondral modeling theory. The shape-optimized model exhibits increased joint congruence, broader stress distributions in articular cartilage, and a relative decrease in joint diameter. The results for the computational model correspond well with experimental data and provide valuable insights into the mechanical determinants of joint growth. The model also provides a crucial first step toward developing a comprehensive model that can be employed to test the influence of mechanical variables on joint conformation.
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Reza AT, Nicoll SB. Serum-free, chemically defined medium with TGF-beta(3) enhances functional properties of nucleus pulposus cell-laden carboxymethylcellulose hydrogel constructs. Biotechnol Bioeng 2010; 105:384-95. [PMID: 19777586 DOI: 10.1002/bit.22545] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Degeneration of the nucleus pulposus (NP) has been implicated as a major cause of low back pain. Tissue engineering strategies may provide a viable NP replacement therapy; however, culture conditions must be optimized to promote functional tissue development. In this study, a standard serum-containing medium formulation was compared to a chemically defined, serum-free medium to determine the effect on matrix elaboration and functional properties of NP cell-laden carboxymethylcellulose (CMC) hydrogels. Additionally, both media were further supplemented with transforming growth factor-beta 3 (TGF-beta(3)). Glycosaminoglycan (GAG) content increased in both TGF-beta(3)-treated groups and was highest for treated, serum-free constructs (9.46 +/- 1.51 microg GAG/mg wet weight), while there were no quantifiable GAGs in untreated serum-containing samples. Histology revealed uniform, interterritorial staining for chondroitin sulfate proteoglycan throughout the treated, serum-free constructs. Type II collagen content was greater in both serum-free groups and highest in treated, serum-free constructs. The equilibrium Young's modulus was highest in serum-free samples supplemented with TGF-beta(3) (18.54 +/- 1.92 kPa), and the equilibrium weight swelling ratio of these constructs approached that of the native NP tissue (22.19 +/- 0.46 vs. 19.94 +/- 3.09, respectively). Taken together, these results demonstrate enhanced functional matrix development by NP cells when cultured in CMC hydrogels maintained in serum-free, TGF-beta(3) supplemented medium, indicating the importance of medium formulation in NP construct development.
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Affiliation(s)
- Anna T Reza
- Department of Bioengineering, University of Pennsylvania, Philadelphia, 19104, USA
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Reza AT, Nicoll SB. Characterization of novel photocrosslinked carboxymethylcellulose hydrogels for encapsulation of nucleus pulposus cells. Acta Biomater 2010; 6:179-86. [PMID: 19505596 DOI: 10.1016/j.actbio.2009.06.004] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2009] [Revised: 05/26/2009] [Accepted: 06/01/2009] [Indexed: 02/07/2023]
Abstract
Back pain is a significant clinical concern often associated with degeneration of the intervertebral disc (IVD). Tissue engineering strategies may provide a viable IVD replacement therapy; however, an ideal biomaterial scaffold has yet to be identified. One candidate material is carboxymethylcellulose (CMC), a water-soluble derivative of cellulose. In this study, 90 and 250 kDa CMC polymers were modified with functional methacrylate groups and photocrosslinked to produce hydrogels at different macromer concentrations. At 7 days, bovine nucleus pulposus (NP) cells encapsulated in these hydrogels were viable, with values for the elastic modulus ranging from 1.07 + or - 0.06 to 4.29 + or - 1.25 kPa. Three specific formulations were chosen for further study based on cell viability and mechanical integrity assessments: 4% 90 kDa, 2% 250 kDa and 3% 250 kDa CMC. The equilibrium weight swelling ratio of these formulations remained steady throughout the 2 week study (46.45 + or - 3.14, 48.55 + or - 2.91 and 42.41 + or - 3.06, respectively). The equilibrium Young's modulus of all cell-laden and cell-free control samples decreased over time, with the exception of cell-laden 3% 250 kDa CMC constructs, indicating an interplay between limited hydrolysis of interchain crosslinks and the elaboration of a functional matrix. Histological analyses of 3% 250 kDa CMC hydrogels confirmed the presence of rounded cells in lacunae and the pericellular deposition of chondroitin sulfate proteoglycan, a phenotypic NP marker. Taken together, these studies support the use of photocrosslinked CMC hydrogels as tunable biomaterials for NP cell encapsulation.
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Le Maitre CL, Fotheringham AP, Freemont AJ, Hoyland JA. Development of an in vitro model to test the efficacy of novel therapies for IVD degeneration. J Tissue Eng Regen Med 2009; 3:461-9. [PMID: 19444863 DOI: 10.1002/term.180] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Low back pain (LBP) is a major cause of disability worldwide that has been linked to intervertebral disc (IVD) degeneration. An improved understanding of the pathogenesis of disc degeneration is now developing, which is leading to the development of a number of possible future therapies targeted at the underlying pathology and regeneration strategies. Although results thus far are promising, the investigation of such therapies in an environment that mimics the mechanical environment of the human disc in vivo is problematic. The development of an in vitro model system that can maintain metabolically active IVD tissue within a loading environment pertaining to that of the human spine is crucial for testing the efficacy of future cell-based and tissue-engineering therapies for IVD degeneration. Here, using our novel loading rig, capable of mimicking the loading environment experienced within the human spine, we have cultured nucleus pulposus tissue explants, applied a daily hydrostatic loading regime for up to 2 weeks and investigated proteoglycan retention, metabolic activity and cellular phenotype. IVD tissue cultured under a loading environment pertaining to the in vivo loading environment maintained metabolic cell activity, proteoglycan content and cellular phenotype. Indeed, all parameters were improved in IVD tissue cultured with load compared to unloaded controls. Such a model is invaluable for investigations assessing the feasibility and efficacy of future therapeutic approaches to inhibiting degeneration or stimulating regeneration of the IVD, where the in vivo loading environment may be crucial to their success or failure.
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Affiliation(s)
- Christine L Le Maitre
- Biomedical Research Centre, Biosciences, Sheffield Hallam University, City Campus, Owen Building, Howard Street, Sheffield S1 1WB, UK
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Cellular mechanobiology of the intervertebral disc: new directions and approaches. J Biomech 2009; 43:137-45. [PMID: 19828150 DOI: 10.1016/j.jbiomech.2009.09.019] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/21/2009] [Indexed: 01/08/2023]
Abstract
The more we learn about the intervertebral disc (IVD), the more we come to appreciate the intricacies involved in transmission of forces through the ECM to the cell, and in the biological determinants of its response to mechanical stress. This review highlights recent developments in our knowledge of IVD physiology and examines their impact on cellular mechanobiology. Discussion centers around the continually evolving cellular and microstructural anatomy of the nucleus pulposus (NP) and the annulus fibrosus (AF) in response to complex stresses generated in support of axial load and spinal motion. Particular attention has been given to cells from the immature NP and the interlamellar AF, and assessment of their potential mechanobiologic contributions to the health and function of the IVD. In addition, several innovative approaches that have been brought to bear on studying the interplay between disc cells and their micromechanical environment are discussed. Techniques for "engineering" cellular function and technologies for fabricating more structurally defined biomaterial scaffolds have recently been employed in disc research. Such tools can be used to elucidate the biological and physical mechanisms by which different IVD cell populations are regulated by mechanical stress, and contribute to advancement of preventative and therapeutic measures.
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Wuertz K, Godburn K, MacLean JJ, Barbir A, Donnelly JS, Roughley PJ, Alini M, Iatridis JC. In vivo remodeling of intervertebral discs in response to short- and long-term dynamic compression. J Orthop Res 2009; 27:1235-42. [PMID: 19274755 PMCID: PMC2757138 DOI: 10.1002/jor.20867] [Citation(s) in RCA: 119] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2008] [Accepted: 01/27/2009] [Indexed: 02/04/2023]
Abstract
This study evaluated how dynamic compression induced changes in gene expression, tissue composition, and structural properties of the intervertebral disc using a rat tail model. We hypothesized that daily exposure to dynamic compression for short durations would result in anabolic remodeling with increased matrix protein expression and proteoglycan content, and that increased daily load exposure time and experiment duration would retain these changes but also accumulate changes representative of mild degeneration. Sprague-Dawley rats (n = 100) were instrumented with an Ilizarov-type device and divided into three dynamic compression (2 week-1.5 h/day, 2 week-8 h/day, 8 week-8 h/day at 1 MPa and 1 Hz) and two sham (2 week, 8 week) groups. Dynamic compression resulted in anabolic remodeling with increased matrix mRNA expression, minimal changes in catabolic genes or disc structure and stiffness, and increased glysosaminoglycans (GAG) content in the nucleus pulposus. Some accumulation of mild degeneration with 8 week-8 h included loss of annulus fibrosus GAG and disc height although 8-week shams also had loss of disc height, water content, and minor structural alterations. We conclude that dynamic compression is consistent with a notion of "healthy" loading that is able to maintain or promote matrix biosynthesis without substantially disrupting disc structural integrity. A slow accumulation of changes similar to human disc degeneration occurred when dynamic compression was applied for excessive durations, but this degenerative shift was mild when compared to static compression, bending, or other interventions that create greater structural disruption.
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Affiliation(s)
- Karin Wuertz
- Spine Bioengineering Lab, School of Engineering, University of Vermont, 33 Colchester Avenue, 201 Perkins Hall, Burlington, Vermont 05405
- Spine Research Unit, University Hospital Balgrist, University of Zurich, Zurich, Switzerland
| | - Karolyn Godburn
- Spine Bioengineering Lab, School of Engineering, University of Vermont, 33 Colchester Avenue, 201 Perkins Hall, Burlington, Vermont 05405
| | - Jeffrey J. MacLean
- Spine Bioengineering Lab, School of Engineering, University of Vermont, 33 Colchester Avenue, 201 Perkins Hall, Burlington, Vermont 05405
| | - Ana Barbir
- Spine Bioengineering Lab, School of Engineering, University of Vermont, 33 Colchester Avenue, 201 Perkins Hall, Burlington, Vermont 05405
| | - Justin Stinnett Donnelly
- Spine Bioengineering Lab, School of Engineering, University of Vermont, 33 Colchester Avenue, 201 Perkins Hall, Burlington, Vermont 05405
| | - Peter J. Roughley
- Genetics Unit, Shriners Hospital for Children, Montreal, Quebec, Canada
| | - Mauro Alini
- AO Research Institute, Davos Platz, Switzerland
| | - James C. Iatridis
- Spine Bioengineering Lab, School of Engineering, University of Vermont, 33 Colchester Avenue, 201 Perkins Hall, Burlington, Vermont 05405
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33
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Nakamura T, Iribe T, Asou Y, Miyairi H, Ikegami K, Takakuda K. Effects of compressive loading on biomechanical properties of disc and peripheral tissue in a rat tail model. 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 2009; 18:1595-603. [PMID: 19557442 DOI: 10.1007/s00586-009-1078-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2008] [Revised: 04/02/2009] [Accepted: 06/10/2009] [Indexed: 11/30/2022]
Abstract
Intervertebral disc degeneration induced by mechanical compression is an important issue in spinal disorder research. In this study, the biomechanical aspect of the rat tail model was investigated. An external loading device equipped with super-elastic TiNi springs was developed to apply a precise load to the rat tail. By using this device, rat tail discs were subjected to compressive stress of 0.5 or 1.0 MPa for 2 weeks. Discs in the sham group received an attachment of the device but no loading. After the experimental period, first the intact tail with peripheral tissues (PT) such as tendon and skin and then the retrieved disc without PT were subjected to a uniaxial tension-compression test; biomechanical characteristics such as range of motion (ROM), neutral zone (NZ), and hysteresis loss (HL) were evaluated. Furthermore, the load-bearing contribution of PT in the intact tail was estimated by comparing the load-displacement curves obtained by the mechanical tests performed with and without PT. The experimental findings revealed that the continuous compressive stress induced reduction in disc thickness. The intact tail demonstrated decreases in ROM and NZ as well as increases in HL. On the other hand, the retrieved disc demonstrated increases in ROM, NZ, and HL. Further, a significant increase in the load-bearing contribution of PT was indicated. These findings suggest that the load-bearing capacity of the disc was seriously deteriorated by the application of compressive stress of 0.5 or 1.0 MPa for 2 weeks.
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Affiliation(s)
- Tomokazu Nakamura
- Department of Mechanical System Engineering, Graduate School of Advanced Science and Technology, Tokyo Denki University, 2-2 Kanda-Nishikicho, Chiyoda-ku, Tokyo 101-8457, Japan
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Knight K, Woods DM, Mchaourab A. Nucleoplasty for disc protrusion: A novel percutaneous decompression technique. ACTA ACUST UNITED AC 2009. [DOI: 10.1053/j.trap.2009.05.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Chou AI, Reza AT, Nicoll SB. Distinct intervertebral disc cell populations adopt similar phenotypes in three-dimensional culture. Tissue Eng Part A 2009; 14:2079-87. [PMID: 18636941 DOI: 10.1089/ten.tea.2007.0337] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Tissue engineering strategies have the potential to improve upon current techniques for intervertebral disc repair. However, determining a suitable biomaterial scaffold for disc regeneration is difficult due to the complex fibrocartilaginous structure of the tissue. In this study, cells isolated from three distinct regions of the intervertebral disc, the outer and inner annulus fibrosus and nucleus pulposus, were expanded and seeded on resorbable polyester fiber meshes and encapsulated in calcium crosslinked alginate hydrogels, both chosen to approximate the native tissue architecture. Three-dimensional (3D) constructs were cultured for 14 days in vitro and evaluated histologically and quantitatively for gene expression and production of types I and II collagen and proteoglycans. During monolayer expansion, the cell populations maintained their distinct phenotypic morphology and gene expression profiles. However, after 14 days in 3D culture, there were no significant differences in morphology, gene expression, or protein production between all three cell populations grown in either alginate or polyester fiber meshes. The results of this study indicate that the culture environment may have a greater impact on cellular behavior than the intrinsic origin of the cells, and suggest that only a single-cell type may be required for intervertebral disc regenerative therapies.
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Affiliation(s)
- Alice I Chou
- Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6321, USA
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36
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Eggum TJ, Hunter CJ. Development and Validation of a System for the Growth of Cells and Tissues Under Intermittent Hydrostatic Pressure. J Biomech Eng 2008; 130:064501. [DOI: 10.1115/1.2979864] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Various cell populations have been shown to respond to hydrostatic pressure; however, many of the culture systems suffer from shortcomings in design or methodology. Of particular interest to us is the potential role of pressure and other environmental factors in modulating stem cell behavior in intervertebral disk repair. A system was developed for the growth of cells and tissues under intermittent hydrostatic pressure. The system was validated with NIH 3T3 fibroblasts for sterilizability and cytotoxicity. Further experiments were conducted with canine mesenchymal stem cells under various levels of pressure, oxygen, glucose, and conditioned medium. The culture system showed no cytotoxicity and was able to demonstrate that the proliferation and metabolism of mesenchymal stem cells are sensitive to medium glucose and oxygen concentration and hydrostatic pressure. The cells exposed to hydrostatic pressure differed in their morphology from nonexposed cells. The system is capable of supporting long-term cell culture and examining the role of mechanical and environmental stimulation in vivo.
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Affiliation(s)
- Troy J. Eggum
- Department of Mechanical and Manufacturing Engineering, Centre for Bioengineering Research and Education, University of Calgary, Calgary, AB, T2N124, Canada
| | - Christopher J. Hunter
- Department of Mechanical and Manufacturing Engineering, Centre for Bioengineering Research and Education, University of Calgary, Calgary, AB, T2N124, Canada
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Abstract
STUDY DESIGN : We evaluated the degenerative changes to rat tail vertebral discs induced by percutaneous needle puncture, and we compared 2 puncture styles for the depth of needle puncture and the rate of disc degeneration. OBJECTIVE : To develop a simple animal model of disc degeneration. SUMMARY OF BACKGROUND DATA : The study of biologically based treatments for degenerative disc disease depends largely on animal models. Annulus needle puncture in the lumbar spine inducing disc degeneration in rabbits has proven successful, but a similar method has not been evaluated in the tail discs of rats, even though it might produce a desirable model for disc repair studies. METHODS : Two consecutive rat tail vertebral discs, proximal and distal to the eighth coccygeal vertebra, were randomized for injury and control. The disc selected for injury was punctured percutaneously using a 20-gauge needle with either full penetration or half penetration. The discs were harvested 1, 2, and 4 weeks later. Measurements included disc height on molybdenum target digital radiographs, biochemistry (water content, glycosaminoglycans, and hydroxyproline), and histology. RESULTS : Needle punctures with full or half penetration caused significant disc space narrowing and progressive histologic changes of degeneration as early as 1 and 2 weeks after injury, respectively. Significant decrease in glycosaminoglycan content was observed at 4 weeks in the half-penetration puncture discs and at 2 and 4 weeks in discs punctured penetratively. Penetrative puncture resulted in a faster decrease in disc height, lower glycosaminoglycan content, and higher grades of histologic degeneration. The water and hydroxyproline content of the discs did not change appreciably. CONCLUSION : Tail disc percutaneous needle puncture is a simple method for inducing disc degeneration and the rate of degeneration is positively related to the depth of needle puncture. This model still has some limitations that should be taken into consideration when results of disc regeneration research in this model are interpreted and extrapolated to human.
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Sebastine IM, Williams DJ. Current developments in tissue engineering of nucleus pulposus for the treatment of intervertebral disc degeneration. ACTA ACUST UNITED AC 2008; 2007:6401-6. [PMID: 18003487 DOI: 10.1109/iembs.2007.4353821] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The main cause for back pain is considered to be the degenerative changes in the intervertebral disc (IVD). Some evidence indicates that IVD degeneration originates from the nucleus pulposus (NP). The IVD does not possess self repair capacity. Current treatment options range from pain management to invasive procedures. The science of disc cell transplantation is still in its infancy. Advancement in bioengineering based upon tissue engineering techniques may offer the possibility of repairing damaged disc, if an engineered NP with the appropriate functional properties can be generated to augment the degenerated disc. This is likely to require triaxial stimulation of tissue engineering constructs.
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Affiliation(s)
- Immanuel M Sebastine
- Wolfson School of Mechanical and Manufacturing Engineering, Loughborough University, Loughborough, LE11 3TU, UK.
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Evidence-informed management of chronic low back pain with minimally invasive nuclear decompression. Spine J 2008; 8:150-9. [PMID: 18164463 DOI: 10.1016/j.spinee.2007.10.019] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2007] [Accepted: 10/15/2007] [Indexed: 02/03/2023]
Abstract
The management of chronic low back pain (CLBP) has proven very challenging in North America, as evidenced by its mounting socioeconomic burden. Choosing among available nonsurgical therapies can be overwhelming for many stakeholders, including patients, health providers, policy makers, and third-party payers. Although all parties share a common goal and wish to use limited health-care resources to support interventions most likely to result in clinically meaningful improvements, there is often uncertainty about the most appropriate intervention for a particular patient. To help understand and evaluate the various commonly used nonsurgical approaches to CLBP, the North American Spine Society has sponsored this special focus issue of The Spine Journal, titled Evidence Informed Management of Chronic Low Back Pain Without Surgery. Articles in this special focus issue were contributed by leading spine practitioners and researchers, who were invited to summarize the best available evidence for a particular intervention and encouraged to make this information accessible to nonexperts. Each of the articles contains five sections (description, theory, evidence of efficacy, harms, and summary) with common subheadings to facilitate comparison across the 24 different interventions profiled in this special focus issue, blending narrative and systematic review methodology as deemed appropriate by the authors. It is hoped that articles in this special focus issue will be informative and aid in decision making for the many stakeholders evaluating nonsurgical interventions for CLBP.
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Hydrostatic pressure differentially regulates outer and inner annulus fibrosus cell matrix production in 3D scaffolds. Ann Biomed Eng 2007; 36:204-13. [PMID: 18026839 DOI: 10.1007/s10439-007-9407-6] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2007] [Accepted: 11/08/2007] [Indexed: 01/07/2023]
Abstract
Mechanical stimulation may be used to enhance the development of engineered constructs for the replacement of load bearing tissues, such as the intervertebral disc. This study examined the effects of dynamic hydrostatic pressure (HP) on outer and inner annulus (OA, IA) fibrosus cells seeded on fibrous poly(glycolic acid)-poly(L-lactic acid) scaffolds. Constructs were pressurized (5 MPa, 0.5 Hz) for 4 h/day from day 3 to day 14 of culture and analyzed using ELISAs and immunohistochemistry (IHC) to assess extracellular matrix (ECM) production. Both cell types were viable, with OA cells exhibiting more infiltration into the scaffold, which was enhanced by HP. ELISA analyses revealed that HP had no effect on type I collagen production while a significant increase in type II collagen (COL II) was measured in pressurized OA constructs compared to day 14 unloaded controls. Both OA and IA dynamically loaded scaffolds exhibited more uniform COL II elaboration as shown by IHC analyses, which was most pronounced in OA-seeded scaffolds. Overall, HP resulted in enhanced ECM elaboration and organization by OA-seeded constructs, while IA-seeded scaffolds were less responsive. As such, hydrostatic pressurization may be beneficial in annulus fibrosus tissue engineering when applied in concert with an appropriate cell source and scaffold material.
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Guehring T, Omlor GW, Lorenz H, Engelleiter K, Richter W, Carstens C, Kroeber M. Disc distraction shows evidence of regenerative potential in degenerated intervertebral discs as evaluated by protein expression, magnetic resonance imaging, and messenger ribonucleic acid expression analysis. Spine (Phila Pa 1976) 2006; 31:1658-65. [PMID: 16816759 DOI: 10.1097/01.brs.0000224558.81765.56] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN An animal model of degeneration was used to determine the effects of disc distraction, and was evaluated with magnetic resonance imaging (MRI) as well as gene and protein expression levels. OBJECTIVE To investigate gene expression and MRI effects of distraction. SUMMARY OF BACKGROUND DATA Disc degeneration can result from hyper-physiologic loading. Distracted discs with degeneration showed histologic signs of tissue recovery. METHODS There were 18 rabbits that underwent 28 days of compression (200 N) to induce moderate disc degeneration followed by 28 days of distraction (120 N; attached and loaded distraction device) or sham distraction (attached but unloaded distraction device). Comparison was performed with 56 days of compressed discs without distraction. Quantitative outcome measures were MRI signal intensity and gene expression analysis to determine: messenger ribonucleic acid levels for extracellular matrix genes, including collagen 1, collagen 2, biglycan, decorin, aggrecan, fibromodulin, and osteonectin; and matrix-regulative genes, including matrix metalloproteinase-13, tissue-inhibitor of matrix metalloproteinase-1, and bone morphogenetic protein (BMP)-2. Immunohistology was performed for collagen 2 and BMP-2 to label cells semiquantitatively by staining of the cell-surrounding matrix. RESULTS A total of 28 days of compression decreased signal intensity. Distraction over the same period reestablished physiologic signal intensity, however, a persistent reduction was found in sham distraction. Distraction resulted in gene expression up-regulation of collagen 1 (5.4-fold), collagen 2 (5.5-fold), biglycan (7.7-fold), and decorin (3.4-fold), while expression of fibromodulin (0.16-fold), tissue-inhibitor of matrix metalloproteinase-1 (0.05-fold), and BMP-2 (0.15-fold) was decreased, as compared with 56 days compression. Distracted discs showed more BMP-2 (19.67 vs. 3.67 in 56 days compression) and collagen 2 (18.67 vs. 11.33 in 56 days compression) positive cells per field. CONCLUSIONS Distraction results in disc rehydration, stimulated extracellular matrix gene expression, and increased numbers of protein-expressing cells.
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Affiliation(s)
- Thorsten Guehring
- Department of Orthopaedic Surgery, University of Heidelberg, Germany.
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Lee CR, Iatridis JC, Poveda L, Alini M. In vitro organ culture of the bovine intervertebral disc: effects of vertebral endplate and potential for mechanobiology studies. Spine (Phila Pa 1976) 2006; 31:515-22. [PMID: 16508544 PMCID: PMC7187957 DOI: 10.1097/01.brs.0000201302.59050.72] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN Whole bovine coccygeal discs were cultured under static load, with or without vertebral endplates (VEPs), and assessed for cell viability, biochemical stability, biosynthetic activity, and biosynthetic responsiveness to changes in mechanical load. OBJECTIVES To assess the effects of VEPs on biochemical and cellular stability of disc cells during in vitro culture of large disc explants. To determine whether cultured discs could respond to mechanical perturbation. SUMMARY OF BACKGROUND DATA Previous methods for culturing the intervertebral disc have focused on rabbit and rat discs, but the small size of these discs limits the relevance of these culture systems to the human condition. Bovine coccygeal discs have similar dimensions to the human lumbar disc (i.e., similar size and nominal stresses), but long-term culture of these discs has not been reported. METHODS Bovine coccygeal discs were harvested with or without VEPs, cultured under static load (5 kg, approximately 0.25 MPa, in situ swelling pressure) for up to 1 week, and evaluated for changes in hydration, glycosaminoglycan content, cell viability, and biosynthetic activity. Additionally, the biochemical and biosynthetic response of discs cultured without VEP to increasing the load to a 20-kg (approximately 1 MPa, the estimated stress in human lumbar disc during heavy lifting) static load for 6 hours was assessed. RESULTS During the first 24 hours, culturing discs with endplates was moderately better with regards to maintaining in situ anulus hydration and nucleus glycosaminoglycan levels. The endplates, however, obstructed media flow to the disc, resulting in a marked decrease in cell viability after 1 week of culture. Nucleus pulposus cell viability was maintained in discs cultured without endplates, but there was a significant drop in biosynthetic activity within 2 days of culture. Despite this drop, the disc cells in the discs without VEP remained biosynthetically responsive to changes in mechanical loading. CONCLUSIONS It is possible to maintain cell viability and the biosynthetic responsiveness of large discs for up to 1 week in vitro when the discs are cultured under static load and without VEP.
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Affiliation(s)
- Cynthia R. Lee
- Biochemistry and Cell Biology Division, AO Research Institute, Davos, Switzerland
- Department of Mechanical Engineering, University of Vermont, Burlington, VT
| | - James C. Iatridis
- Department of Mechanical Engineering, University of Vermont, Burlington, VT
| | - Lucy Poveda
- Biochemistry and Cell Biology Division, AO Research Institute, Davos, Switzerland
| | - Mauro Alini
- Biochemistry and Cell Biology Division, AO Research Institute, Davos, Switzerland
- Orthopaedic Research Laboratory, McGill University, Montreal, Quebec, Canada
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Miyamoto H, Doita M, Nishida K, Yamamoto T, Sumi M, Kurosaka M. Effects of cyclic mechanical stress on the production of inflammatory agents by nucleus pulposus and anulus fibrosus derived cells in vitro. Spine (Phila Pa 1976) 2006; 31:4-9. [PMID: 16395168 DOI: 10.1097/01.brs.0000192682.87267.2a] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN Cyclic mechanical stress (CMS) was applied to cultured nucleus pulposus and anulus fibrosus cells, and the production of inflammatory agents by these cells was evaluated. OBJECTIVE To investigate the involvement of CMS in the production of inflammatory agents by disc cells. SUMMARY OF BACKGROUND DATA It has been reported that CMS affects degeneration of the disc. However, little is known about the effect of CMS on the production of inflammatory agents by both cell types in vitro. METHODS Cells derived from nucleus pulposus and anulus fibrosus of Sprague-Dawley rat tails were cultured with or without CMS applied by the Flexercell Strain Unit (Flexcell International Corp., Hillsborough, NC) in the presence or absence of inflammatory stimulus. Doses of prostaglandin-E2 (PGE2) were measured in the culture supernatants. Semiquantitative evaluations of the expressions of cyclooxygenase (COX)-2 and phospholipase-A2 IIA messenger ribonucleic acids (mRNAs) were also examined. RESULTS Sole application of CMS on nucleus pulposus and anulus fibrosus cells increased PGE2 synthesis. Coincidence of CMS and inflammatory stimulus synergistically enhanced PGE2 synthesis of both cell types. Anulus fibrosus cells showed a stronger reactivity to these stimuli than nucleus pulposus cells. The expression of COX-2 mRNA of anulus fibrosus cells tended to correlate to the amount of PGE2, whereas COX-2 mRNA was constitutively expressed in nucleus pulposus cells, suggesting that the roles of COX-2 might be different between nucleus pulposus and anulus fibrosus. Phospholipase-A2 IIA mRNA was constitutively expressed in both cell types. CONCLUSIONS The results of this study suggested that CMS might be involved in the pathomechanism of pain induction of lumbar disc diseases.
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Affiliation(s)
- Hiroshi Miyamoto
- Department of Orthopaedic Surgery, Kobe University Graduate School of Medicine, Japan.
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MacLean JJ, Lee CR, Alini M, Iatridis JC. The effects of short-term load duration on anabolic and catabolic gene expression in the rat tail intervertebral disc. J Orthop Res 2005; 23:1120-7. [PMID: 16140193 DOI: 10.1016/j.orthres.2005.01.020] [Citation(s) in RCA: 103] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2004] [Revised: 11/17/2004] [Accepted: 01/28/2005] [Indexed: 02/04/2023]
Abstract
The goal of this study was to determine the time-dependent response of the intervertebral disc cells to in vivo dynamic compression. Forty-seven skeletally mature Wistar rats (>12 months old) were instrumented with an Ilizarov-type device spanning caudal disc 8-9. Using a load magnitude (1 MPa) and frequency (1.0 Hz) that were previously shown to significantly alter mRNA levels in the disc, the effects of 0.5 and 4 h of loading were investigated and compared to a sham group and our previous 2 h results. Annulus and nucleus tissue of loaded (c8-9) and internal control discs (c6-7 and c10-11) were separately analyzed by real-time RT-PCR for levels of mRNA coding for various anabolic (collagen-1A1, collagen-2A1, aggrecan) and catabolic (MMP-3, MMP-13, ADAMTs-4) proteins. In the annulus, mRNA levels increased for Collagen types I & II, and MMP 3 & 13 with increasing load duration. In contrast, the nucleus had the largest increases in aggrecan, ADAMTs-4, MMP-3 and MMP-13 after 2 h of loading, with aggrecan and MMP-13 mRNA levels returning to control values after 4 h of loading. Taken in context with our previous studies, we conclude that intervertebral disc cells from the nucleus and annulus have distinct responses to dynamic mechanical compression in vivo with sensitivity to compression magnitude, frequency and duration.
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Affiliation(s)
- Jeffery J MacLean
- Department of Mechanical Engineering, University of Vermont, Burlington, VT 05405-0156, USA.
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45
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Neidlinger-Wilke C, Würtz K, Liedert A, Schmidt C, Börm W, Ignatius A, Wilke HJ, Claes L. A three-dimensional collagen matrix as a suitable culture system for the comparison of cyclic strain and hydrostatic pressure effects on intervertebral disc cells. J Neurosurg Spine 2005; 2:457-65. [PMID: 15871486 DOI: 10.3171/spi.2005.2.4.0457] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECT To study intervertebral disc cell mechanobiology, the authors developed experimental systems that allow the application of cyclic strain and intermittent hydrostatic pressure (IHP) on isolated disc cells under equal three-dimensional (3D) culture conditions. The purpose of the study was to characterize disc cell proliferation, viability, morphology, and gene expression in 3D collagen matrices. METHODS The effects of cyclic strain (1, 2, 4, and 8% strain; 1 Hz) and IHP (0.25 MPa, 0.1 Hz) on gene expression (real-time polymerase chain reaction) of anabolic and catabolic matrix proteins were investigated and compared with those derived from mechanically unstimulated controls. Intervertebral disc cells proliferated in the collagen gels (mean viability 91.6%) and expressed messenger RNA for collagen I, collagen II, aggrecan, matrix metalloproteinase (MMP)-2, and MMP-3. Morphologically, both spindle-shaped cells with longer processes and rounded cells were detected in the collagen scaffolds. Cyclic strain increased collagen II and aggrecan expression and decreased MMP-3 expression of anulus fibrosus cells. No significant difference between the four strain magnitudes was found. Intermittent hydrostatic pressure tended to increase collagen I and aggrecan expression of nucleus cells and significantly decreased MMP-2 and -3 expression of nucleus cells, whereas aggrecan expression of anulus cells tended to decrease. CONCLUSIONS Based on these results, the collagen matrix appeared to be a suitable substrate to apply both cyclic strain and IHP to intervertebral disc cells under 3D culture conditions. Individual variations may be influenced by the extent of degeneration of the disc specimens from which the cells were isolated. This experimental setup may be suitable for studying the influence of degeneration on the disc cell response to mechanical stimuli.
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Wenger KH, Woods JA, Holecek A, Eckstein EC, Robertson JT, Hasty KA. Matrix remodeling expression in anulus cells subjected to increased compressive load. Spine (Phila Pa 1976) 2005; 30:1122-6. [PMID: 15897824 DOI: 10.1097/01.brs.0000162395.56424.53] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN Mechanobiology study of gene expression changes as a result of compressive overload of anular fibrochondrocytes. OBJECTIVE To test hypotheses regarding phenotype shift in genes coding for representative extracellular matrix (ECM) proteins and matrix modulators. SUMMARY OF THE BACKGROUND DATA In degenerative disc disease, the transfer of compressive load through the disc shifts largely from the nucleus onto the anulus. In vivo models simulating this condition have shown derangement of the collagenous ultrastructure in the anulus. In vitro models of cultured anulus cells subjected to static compressive stress generally suggest a down-regulation of synthesis. This study evaluated the expression of specific isomers of genes responsible for mechanical viability and metabolism of the disc under cyclic compressive loads. METHODS Fibrochondrocytes were digested from the anuli of 3, 2-week-old pigs, embedded in 1.5% alginate gel, and hydrostatically compressed at 0.5 Hz for 3 hours to amplitudes of 10 and 30 atm. These levels represented nominal load transfer through the healthy disc and high load transfer through the degenerative disc. Ribonucleic acid was isolated, reverse transcribed, and evaluated by real-time polymerase chain reaction for expression of type I (C-I) and type II (C-II) collagen, aggrecan, the matrix metalloproteinase (MMP-1), and the transforming growth factor beta (TGFbeta-1). Results were expressed at percentages of uncompressed controls. RESULTS The lower pressure of 10 atm resulted in up-regulation of all ECM protein genes. C-I and C-II both averaged 141%, and aggrecan 121% of controls (P < 0.05). MMP-1 and TGFbeta-1 were essentially unchanged. With the pressure increased to 30 atm, C-II remained approximately at the level expressed under lower pressure, but C-I was reduced to 42% of controls (P < 0.05), indicating a phenotype shift. MMP-1 and TGFbeta-1 also were down-regulated to 71% and 54% of controls, respectively (P < 0.05). CONCLUSIONS The up-regulation of the ECM genes with nominal pressure highlights the mechanobiological importance of common activity in fibrocartilage homeostasis. Differential regulation of the 2 primary collagen types with high pressure indicates a capacity of the anulus to remodel according to pathomechanical conditions.
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Affiliation(s)
- Karl H Wenger
- Department of Rheumatology, University of Tennessee Health Science Center, Memphis, TN, USA.
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Kim KS, Yoon ST, Li J, Park JS, Hutton WC. Disc degeneration in the rabbit: a biochemical and radiological comparison between four disc injury models. Spine (Phila Pa 1976) 2005; 30:33-7. [PMID: 15626978 DOI: 10.1097/01.brs.0000149191.02304.9b] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN A biochemical and radiologic comparison of 4 disc injury models to produce disc degeneration in the rabbit was carried out in 2 experiments. OBJECTIVES To develop a reliable animal model of intervertebral disc degeneration. SUMMARY OF BACKGROUND DATA In order to study various interventions for retarding or preventing disc degeneration, a reliable animal model of disc degeneration is needed. METHODS First experiment: 7 New Zealand white rabbits (1 year old, 3.5-4.5 kg body weight) were used to test 4 different disc injury models; intradiscal injection of Camptothecin (an apoptotic agent) using a 23-gauge needle at L2-L3, nucleus aspiration using a 21-gauge needle at L3-L4, 3 anulus punctures using a 21-gauge needle at L4-L5, and 1 anulus puncture using a 18-gauge needle at L5-L6. The L1-L2 level was used as a control. Rabbits were killed 12 weeks later. Lumbar spinal magnetic resonance images were assessed using 4 grades of disc degeneration. The water content of the nucleus was measured. Dimethylmethylene blue (DMMB) assay was used to measure the sulfated-glycosaminoglycan content. Second experiment: the 21-gauge 3-puncture and the 18-gauge 1-puncture models, thought most effective in producing disc degeneration in the first experiment, were again used in a second study. Six rabbits were killed 8 weeks later, the water and sulfated-glycosaminoglycan contents being measured as in the first experiment. RESULTS In the first experiment, the water content in the aspiration and puncture models was significantly decreased. Only the sulfated-glycosaminoglycan content in the aspiration model showed a significant decrease as compared to the control. Disc heights and magnetic resonance grades documented significant degeneration occurring in the aspiration and puncture models. In the second experiment, the water content showed a significant decrease in the 21-gauge 3-puncture model, whereas neither of the results for the sulfated-glycosaminoglycancontent showed a significant difference as compared to the control data. CONCLUSION In the first experiment, the 21-gauge 3-puncture and the 18-gauge 1-puncture models produced the most consistent disc degeneration in the rabbit lumbar spine. When these 2 models were again studied in the second experiment, the 21-gauge 3-puncture technique was superior in producing disc degeneration over a shorter period of time.
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Affiliation(s)
- Keun Su Kim
- Department of Neurosurgery, Yongdong Severance Hospital, Yonsei University College of Medicine, Seoul, Korea
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Abstract
STUDY DESIGN A review is presented on current knowledge of the micromechanical factors in the intervertebral disc, their role in modifying cell biology, and changes with degeneration. OBJECTIVES To identify current knowledge, knowledge gaps, and areas for future research in micromechanics of the intervertebral disc. SUMMARY OF BACKGROUND DATA Mechanical factors play important roles in the initiation and progression of intervertebral disc degeneration. Evidence suggests that substantial biologic remodeling occurs in the intervertebral disc in response to mechanical stimuli that may play a critical role in determining the fate of a degenerating intervertebral disc. Information is needed on the precise mechanical stimuli that these cells experience and the mechanisms that govern their responses. METHODS A review is presented of cell morphology, cell mechanics, and the internal strains and other mechanical factors predicted to occur at the cell level. A review of intervertebral disc cell responses to well-controlled physical stimuli is also presented with a focus on in vitro studies of explants and isolated cells. RESULTS Important differences in cell morphology, mechanics, micromechanical factors, and mechanobiology are noted to occur between cells of the nucleus pulposus and anulus fibrosus. Changes in these features with degeneration are critically understudied, particularly degeneration-associated changes in cell morphology, cell mechanics, and altered physiology with mechanical loading. CONCLUSIONS Information on the mechanisms that govern cell responses to mechanical stimuli in the intervertebral disc are just emerging. Studies must address determination of the factors that control micromechanical stimuli, but also mechanisms by which mechanics may interact with genetic factors to regulate expression and remodeling of extracellular matrix molecules, cytokines and mediators of pain and inflammation in degenerating tissue.
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Affiliation(s)
- Lori A Setton
- Department of Biomedical Engineering, Division of Orthopaedic Surgery, Duke University, Durham, North Carolina 27708-0281, USA.
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Stokes IAF, Iatridis JC. Mechanical conditions that accelerate intervertebral disc degeneration: overload versus immobilization. Spine (Phila Pa 1976) 2004; 29:2724-32. [PMID: 15564921 PMCID: PMC7173624 DOI: 10.1097/01.brs.0000146049.52152.da] [Citation(s) in RCA: 248] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN A review of the literature on macromechanical factors that accelerate disc degeneration with particular focus on distinguishing the roles of immobilization and overloading. OBJECTIVE This review examines evidence from the literature in the areas of biomechanics, epidemiology, animal models, and intervertebral disc physiology. The purpose is to examine: 1) what are the degeneration-related alterations in structural, material, and failure properties in the disc; and 2) evidence in the literature for causal relationships between mechanical loading and alterations in those structural and material properties that constitute disc degeneration. SUMMARY OF BACKGROUND DATA It is widely assumed that the mechanical environment of the intervertebral disc at least in part determines its rate of degeneration. However, there are two plausible and contrasting theories as to the mechanical conditions that promote degeneration: 1) mechanical overload; and 2) reduced motion and loading. RESULTS There are a greater number of studies addressing the "wear and tear" theory than the immobilization theory. Evidence is accumulating to support the notion that there is a "safe window" of tissue mechanical conditions in which the discs remain healthy. CONCLUSIONS It is concluded that probably any abnormal loading conditions (including overload and immobilization) can produce tissue trauma and/or adaptive changes that may result in disc degeneration. Adverse mechanical conditions can be due to external forces, or may result from impaired neuromuscular control of the paraspinal and abdominal muscles. Future studies will need to evaluate additional unquantified interactions between biomechanics and factors such as genetics and behavioral responses to pain and disability.
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Affiliation(s)
- Ian A F Stokes
- Department of Orthopaedics and Rehabilitation, University of Vermont, Burlington, Vermont 05405, USA
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50
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Maclean JJ, Lee CR, Alini M, Iatridis JC. Anabolic and catabolic mRNA levels of the intervertebral disc vary with the magnitude and frequency of in vivo dynamic compression. J Orthop Res 2004; 22:1193-200. [PMID: 15475197 DOI: 10.1016/j.orthres.2004.04.004] [Citation(s) in RCA: 128] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2004] [Accepted: 04/08/2004] [Indexed: 02/04/2023]
Abstract
The goal of this study was to characterize the anabolic and catabolic mRNA response of the disc to dynamic loading to determine if variations in the magnitude and/or frequency of loading could elicit different cellular responses. Sixty-eight Wistar rats were instrumented with an Ilizarov-type device spanning caudal disc 8-9. Seventy-two hours after surgery, animals were anesthetized and loaded at either 1 or 0.2 MPa at a frequency of 1, 0.2 or 0.01 Hz for 2 h (6 groups). The surgical control (Sham) animals underwent anesthesia with no loading. Loaded (c8-9) and internal-control discs (c6-7 and c10-11) were dissected and annulus and nucleus tissue were separately analyzed by real-time RT-PCR for levels of anabolic (collagen-1A1, collagen-2A1, aggrecan) and catabolic (MMP-3, MMP-13, ADAMTs-4) mRNA. In the nucleus, a frequency-dependent response was seen at 1 MPa with anabolic genes stimulated at 0.01 Hz and catabolic genes at 1 Hz. In the annulus all frequencies resulted in significant up-regulation of catabolic mRNA at 1 MPa loading. In general loading at 0.2 MPa or 0.2 Hz had little effect on gene expression. The results suggest that gene expression of the annulus appears to be more dependent on the magnitude of applied stress, while the nucleus is both magnitude- and frequency-dependent.
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Affiliation(s)
- Jeffery J Maclean
- Department of Mechanical Engineering, University of Vermont, 231B Votey Building, 33 Colchester Avenue, Burlington 05405-0156, USA
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