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McDonnell EE, Wilson N, Barcellona MN, Ní Néill T, Bagnall J, Brama PAJ, Cunniffe GM, Darwish SL, Butler JS, Buckley CT. Preclinical to clinical translation for intervertebral disc repair: Effects of species-specific scale, metabolism, and matrix synthesis rates on cell-based regeneration. JOR Spine 2023; 6:e1279. [PMID: 37780829 PMCID: PMC10540833 DOI: 10.1002/jsp2.1279] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 06/15/2023] [Accepted: 08/24/2023] [Indexed: 10/03/2023] Open
Abstract
Background A significant hurdle for potential cell-based therapies is the subsequent survival and regenerative capacity of implanted cells. While many exciting developments have demonstrated promise preclinically, cell-based therapies for intervertebral disc (IVD) degeneration fail to translate equivalent clinical efficacy. Aims This work aims to ascertain the clinical relevance of both a small and large animal model by experimentally investigating and comparing these animal models to human from the perspective of anatomical scale and their cellular metabolic and regenerative potential. Materials and Methods First, this work experimentally investigated species-specific geometrical scale, native cell density, nutrient metabolism, and matrix synthesis rates for rat, goat, and human disc cells in a 3D microspheroid configuration. Second, these parameters were employed in silico to elucidate species-specific nutrient microenvironments and predict differences in temporal regeneration between animal models. Results This work presents in silico models which correlate favorably to preclinical literature in terms of the capabilities of animal regeneration and predict that compromised nutrition is not a significant challenge in small animal discs. On the contrary, it highlights a very fine clinical balance between an adequate cell dose for sufficient repair, through de novo matrix deposition, without exacerbating the human microenvironmental niche. Discussion Overall, this work aims to provide a path towards understanding the effect of cell injection number on the nutrient microenvironment and the "time to regeneration" between preclinical animal models and the large human IVD. While these findings help to explain failed translation of promising preclinical data and the limited results emerging from clinical trials at present, they also enable the research field and clinicians to manage expectations on cell-based regeneration. Conclusion Ultimately, this work provides a platform to inform the design of clinical trials, and as computing power and software capabilities increase in the future, it is conceivable that generation of patient-specific models could be used for patient assessment, as well as pre- and intraoperative planning.
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Affiliation(s)
- Emily E. McDonnell
- Trinity Centre for Biomedical Engineering, Trinity Biomedical Sciences Institute, Trinity College DublinThe University of DublinDublinIreland
- Discipline of Mechanical, Manufacturing and Biomedical Engineering, School of Engineering, Trinity College DublinThe University of DublinDublinIreland
| | - Niamh Wilson
- Trinity Centre for Biomedical Engineering, Trinity Biomedical Sciences Institute, Trinity College DublinThe University of DublinDublinIreland
- Discipline of Mechanical, Manufacturing and Biomedical Engineering, School of Engineering, Trinity College DublinThe University of DublinDublinIreland
| | - Marcos N. Barcellona
- Trinity Centre for Biomedical Engineering, Trinity Biomedical Sciences Institute, Trinity College DublinThe University of DublinDublinIreland
- Discipline of Mechanical, Manufacturing and Biomedical Engineering, School of Engineering, Trinity College DublinThe University of DublinDublinIreland
| | - Tara Ní Néill
- Trinity Centre for Biomedical Engineering, Trinity Biomedical Sciences Institute, Trinity College DublinThe University of DublinDublinIreland
- Discipline of Mechanical, Manufacturing and Biomedical Engineering, School of Engineering, Trinity College DublinThe University of DublinDublinIreland
| | - Jessica Bagnall
- Trinity Centre for Biomedical Engineering, Trinity Biomedical Sciences Institute, Trinity College DublinThe University of DublinDublinIreland
- Discipline of Mechanical, Manufacturing and Biomedical Engineering, School of Engineering, Trinity College DublinThe University of DublinDublinIreland
| | - Pieter A. J. Brama
- Trinity Centre for Biomedical Engineering, Trinity Biomedical Sciences Institute, Trinity College DublinThe University of DublinDublinIreland
- School of Veterinary MedicineUniversity College DublinDublinIreland
| | - Gráinne M. Cunniffe
- National Spinal Injuries UnitMater Misericordiae University HospitalDublinIreland
- School of MedicineUniversity College DublinDublinIreland
| | - Stacey L. Darwish
- National Spinal Injuries UnitMater Misericordiae University HospitalDublinIreland
- School of MedicineUniversity College DublinDublinIreland
- National Orthopaedic HospitalDublinIreland
- St Vincent's University HospitalDublinIreland
| | - Joseph S. Butler
- Trinity Centre for Biomedical Engineering, Trinity Biomedical Sciences Institute, Trinity College DublinThe University of DublinDublinIreland
- National Spinal Injuries UnitMater Misericordiae University HospitalDublinIreland
- School of MedicineUniversity College DublinDublinIreland
| | - Conor T. Buckley
- Trinity Centre for Biomedical Engineering, Trinity Biomedical Sciences Institute, Trinity College DublinThe University of DublinDublinIreland
- Discipline of Mechanical, Manufacturing and Biomedical Engineering, School of Engineering, Trinity College DublinThe University of DublinDublinIreland
- Advanced Materials and Bioengineering Research (AMBER) Centre, Royal College of Surgeons in Ireland & Trinity College DublinThe University of DublinDublinIreland
- Tissue Engineering Research Group, Department of Anatomy and Regenerative MedicineRoyal College of Surgeons in IrelandDublinIreland
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2
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Abstract
Orchestration of protein production and degradation and the regulation of protein lifetimes play a central role in many basic biological processes. Nearly all mammalian proteins are replenished by protein turnover in waves of synthesis and degradation. Protein lifetimes in vivo are typically measured in days, but a small number of extremely long-lived proteins (ELLPs) persist for months or even years. ELLPs are rare in all tissues but are enriched in tissues containing terminally differentiated post-mitotic cells and extracellular matrix. Consistently, emerging evidence suggests that the cochlea may be particularly enriched in ELLPs. Damage to ELLPs in specialized cell types, such as crystallin in the lens cells of the eye, causes organ failure such as cataracts. Similarly, damage to cochlear ELLPs is likely to occur with many insults, including acoustic overstimulation, drugs, anoxia, and antibiotics, and may play an underappreciated role in hearing loss. Furthermore, hampered protein degradation may contribute to acquired hearing loss. In this review, I highlight our knowledge of the lifetimes of cochlear proteins with an emphasis on ELLPs and the potential contribution that impaired cochlear protein degradation has on acquired hearing loss and the emerging relevance of ELLPs.
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Affiliation(s)
- Jeffrey N Savas
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA.
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3
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Liu Y, Liu DK, Wang ZW, Zhao C, Miao J. Baicalein alleviates TNF-α-induced apoptosis of human nucleus pulposus cells through PI3K/AKT signaling pathway. J Orthop Surg Res 2023; 18:292. [PMID: 37041597 PMCID: PMC10088118 DOI: 10.1186/s13018-023-03759-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Accepted: 03/27/2023] [Indexed: 04/13/2023] Open
Abstract
BACKGROUND Nucleus pulposus (NP) cell apoptosis contributed to disc degeneration. Baicalein, a natural steroid saponin, has been demonstrated to have anti-inflammatory, antiapoptotic, and antioxidative effects in various diseases. However, little is known about the roles of baicalein in intervertebral disc degeneration. METHODS To evaluate the roles of baicalein in disc degeneration and its specific mechanism, human NP cells were incubated with TNF-α and various concentrations of baicalein. Cell viability, extracellular matrix protein expression, catabolic factors, degree of apoptosis, inflammatory factors, and related signaling pathways were evaluated by western blotting, fluorescence immunostaining, TUNEL staining, and reverse transcription PCR. RESULTS Baicalein inhibited TNF-α-activated apoptotic signaling and catabolic activity in NP cells. Baicalein promoted PI3K/Akt signaling and attenuated the level of apoptosis-related markers in TNF-α-stimulated human NP cells. CONCLUSION Our work provides that baicalein attenuates TNF-α-activated apoptosis in human NP cells through promoting the PI3K/Akt pathway, indicating that baicalein is a new potential candidate for clinical therapy to attenuate disc degeneration.
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Affiliation(s)
- Yang Liu
- Graduate School, Tianjin Medical University, Tianjin, 300070, China
| | - Dao-Kuo Liu
- Department of Spinal Surgery, Hebei Province Cangzhou Hospital of Integrated Traditional and Western Medicine, Cangzhou, 061013, China
| | - Zhi-Wei Wang
- Department of Spinal Surgery, Hebei Province Cangzhou Hospital of Integrated Traditional and Western Medicine, Cangzhou, 061013, China
| | - Chong Zhao
- Department of Spinal Surgery, Hebei Province Cangzhou Hospital of Integrated Traditional and Western Medicine, Cangzhou, 061013, China
| | - Jun Miao
- Department of Spine Surgery, Tianjin Hospital, Tianjin University, No. 406 Jiefang South Road, Hexi District, Tianjin, 300211, China.
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4
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Matsubayashi Y. Dynamic movement and turnover of extracellular matrices during tissue development and maintenance. Fly (Austin) 2022; 16:248-274. [PMID: 35856387 PMCID: PMC9302511 DOI: 10.1080/19336934.2022.2076539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 05/04/2022] [Accepted: 05/05/2022] [Indexed: 01/05/2023] Open
Abstract
Extracellular matrices (ECMs) are essential for the architecture and function of animal tissues. ECMs have been thought to be highly stable structures; however, too much stability of ECMs would hamper tissue remodelling required for organ development and maintenance. Regarding this conundrum, this article reviews multiple lines of evidence that ECMs are in fact rapidly moving and replacing components in diverse organisms including hydra, worms, flies, and vertebrates. Also discussed are how cells behave on/in such dynamic ECMs, how ECM dynamics contributes to embryogenesis and adult tissue homoeostasis, and what molecular mechanisms exist behind the dynamics. In addition, it is highlighted how cutting-edge technologies such as genome engineering, live imaging, and mathematical modelling have contributed to reveal the previously invisible dynamics of ECMs. The idea that ECMs are unchanging is to be changed, and ECM dynamics is emerging as a hitherto unrecognized critical factor for tissue development and maintenance.
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Affiliation(s)
- Yutaka Matsubayashi
- Department of Life and Environmental Sciences, Bournemouth University, Talbot Campus, Dorset, Poole, Dorset, UK
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5
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Cui S, Li W, Teixeira GQ, Neidlinger‐Wilke C, Wilke H, Haglund L, Ouyang H, Richards RG, Grad S, Alini M, Li Z. Neoepitope fragments as biomarkers for different phenotypes of intervertebral disc degeneration. JOR Spine 2022; 5:e1215. [PMID: 36203866 PMCID: PMC9520770 DOI: 10.1002/jsp2.1215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Revised: 06/16/2022] [Accepted: 06/17/2022] [Indexed: 11/21/2022] Open
Abstract
Background During the intervertebral disc (IVD) degeneration process, initial degenerative events occur at the extracellular matrix level, with the appearance of neoepitope peptides formed by the cleavage of aggrecan and collagen. This study aims to elucidate the spatial and temporal alterations of aggrecan and collagen neoepitope level during IVD degeneration. Methods Bovine caudal IVDs were cultured under four different conditions to mimic different degenerative situations. Samples cultured after 1‐ or 8‐days were collected for analysis. Human IVD samples were obtained from patients diagnosed with lumbar disc herniation (LDH) or adolescent idiopathic scoliosis (AIS). After immunohistochemical (IHC) staining of Aggrecanase Cleaved C‐terminus Aggrecan Neoepitope (NB100), MMP Cleaved C‐terminus Aggrecan Neoepitope (MMPCC), Collagen Type 1α1 1/4 fragment (C1α1) and Collagenase Cleaved Type I and II Collagen Neoepitope (C1,2C), staining optical density (OD)/area in extracellular matrix (OECM) and pericellular zone (OPCZ) were analyzed. Conditioned media of the bovine IVD was collected to measure protein level of inflammatory cytokines and C1,2C. Results For the bovine IVD sections, the aggrecan MMPCC neoepitope was accumulated in nucleus pulposus (NP) and cartilage endplate (EP) regions following mechanical overload in the one strike model after long‐term culture; as for the TNF‐α induced degeneration, the OECM and OPCZ of collagen C1,2C neoepitope was significantly increased in the outer AF region after long‐term culture; moreover, the C1,2C was only detected in conditioned medium from TNF‐α injection + Degenerative loading group after 8 days of culture. LDH patients showed higher MMPCC OECM in NP and higher C1,2C OECM in AF region compared with AIS patients. Conclusions In summary, aggrecan and collagen neoepitope profiles showed degeneration induction trigger‐ and region‐specific differences in the IVD organ culture models. Different IVD degeneration types are correlated with specific neoepitope expression profiles. These neoepitopes may be helpful as biomarkers of ECM degradation in early IVD degeneration and indicators of different degeneration phenotypes.
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Affiliation(s)
- Shangbin Cui
- AO Research Institute Davos Davos Switzerland
- Guangdong Provincial Key Laboratory of Orthopedics and Traumatology The First Affiliated Hospital of Sun Yat‐Sen University Guangzhou China
| | - Wenyue Li
- AO Research Institute Davos Davos Switzerland
- Zhejiang University‐University of Edinburgh Institute (ZJU‐UoE Institute) Zhejiang University Haining China
| | - Graciosa Q. Teixeira
- Institute of Orthopedic Research and Biomechanics, Centre for Trauma Research Ulm (ZTF Ulm) Ulm University Ulm Germany
| | - Cornelia Neidlinger‐Wilke
- Institute of Orthopedic Research and Biomechanics, Centre for Trauma Research Ulm (ZTF Ulm) Ulm University Ulm Germany
| | - Hans‐Joachim Wilke
- Institute of Orthopedic Research and Biomechanics, Centre for Trauma Research Ulm (ZTF Ulm) Ulm University Ulm Germany
| | - Lisbet Haglund
- Department of Surgery and Shriners Hospital for Children McGill University Montreal Canada
| | - Hongwei Ouyang
- Zhejiang University‐University of Edinburgh Institute (ZJU‐UoE Institute) Zhejiang University Haining China
| | - R. Geoff Richards
- AO Research Institute Davos Davos Switzerland
- Guangdong Provincial Key Laboratory of Orthopedics and Traumatology The First Affiliated Hospital of Sun Yat‐Sen University Guangzhou China
| | | | - Mauro Alini
- AO Research Institute Davos Davos Switzerland
| | - Zhen Li
- AO Research Institute Davos Davos Switzerland
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6
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Zhang S, Liu W, Chen S, Wang B, Wang P, Hu B, Lv X, Shao Z. Extracellular matrix in intervertebral disc: basic and translational implications. Cell Tissue Res 2022; 390:1-22. [DOI: 10.1007/s00441-022-03662-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2022] [Accepted: 06/23/2022] [Indexed: 02/06/2023]
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7
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Baumgartner L, Sadowska A, Tío L, González Ballester MA, Wuertz-Kozak K, Noailly J. Evidence-Based Network Modelling to Simulate Nucleus Pulposus Multicellular Activity in Different Nutritional and Pro-Inflammatory Environments. Front Bioeng Biotechnol 2021; 9:734258. [PMID: 34858955 PMCID: PMC8631496 DOI: 10.3389/fbioe.2021.734258] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 10/08/2021] [Indexed: 01/08/2023] Open
Abstract
Initiation of intervertebral disc degeneration is thought to be biologically driven. This reflects a process, where biochemical and mechanical stimuli affect cell activity (CA) that compromise the tissue strength over time. Experimental research enhanced our understanding about the effect of such stimuli on different CA, such as protein synthesis or mRNA expression. However, it is still unclear how cells respond to their native environment that consists of a “cocktail” of different stimuli that might locally vary. This work presents an interdisciplinary approach of experimental and in silico research to approximate Nucleus Pulposus CA within multifactorial biochemical environments. Thereby, the biochemical key stimuli glucose, pH, and the proinflammatory cytokines TNF-α and IL1β were considered that were experimentally shown to critically affect CA. To this end, a Nucleus Pulposus multicellular system was modelled. It integrated experimental findings from in vitro studies of human or bovine Nucleus Pulposus cells, to relate the individual effects of targeted stimuli to alterations in CA. Unknown stimulus-CA relationships were obtained through own experimental 3D cultures of bovine Nucleus Pulposus cells in alginate beads. Translation of experimental findings into suitable parameters for network modelling approaches was achieved thanks to a new numerical approach to estimate the individual sensitivity of a CA to each stimulus type. Hence, the effect of each stimulus type on a specific CA was assessed and integrated to approximate a multifactorial stimulus environment. Tackled CA were the mRNA expressions of Aggrecan, Collagen types I & II, MMP3, and ADAMTS4. CA was assessed for four different proinflammatory cell states; non-inflamed and inflamed for IL1β, TNF-α or both IL1β&TNF-α. Inflamed cell clusters were eventually predicted in a multicellular 3D agent-based model. Experimental results showed that glucose had no significant impact on proinflammatory cytokine or ADAMTS4 mRNA expression, whereas TNF-α caused a significant catabolic shift in most explored CA. In silico results showed that the presented methodology to estimate the sensitivity of a CA to a stimulus type importantly improved qualitative model predictions. However, more stimuli and/or further experimental knowledge need to be integrated, especially regarding predictions about the possible progression of inflammatory environments under adverse nutritional conditions. Tackling the multicellular level is a new and promising approach to estimate manifold responses of intervertebral disc cells. Such a top-down high-level network modelling approach allows to obtain information about relevant stimulus environments for a specific CA and could be shown to be suitable to tackle complex biological systems, including different proinflammatory cell states. The development of this methodology required a close interaction with experimental research. Thereby, specific experimental needs were derived from systematic in silico approaches and obtained results were directly used to enhance model predictions, which reflects a novelty in this research field. Eventually, the presented methodology provides modelling solutions suitable for multiscale approaches to contribute to a better understanding about dynamics over multiple spatial scales. Future work should focus on an amplification of the stimulus environment by integrating more key relevant stimuli, such as mechanical loading parameters, in order to better approximate native physiological environments.
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Affiliation(s)
- L Baumgartner
- BCN MedTech, Department of Information and Communication Technologies, Universitat Pompeu Fabra, Barcelona, Spain
| | - A Sadowska
- Department of Health Sciences and Technology, Institute for Biomechanics, ETH Zurich, Zurich, Switzerland
| | - L Tío
- IMIM (Hospital del Mar Medical Research Institute), Barcelona, Spain
| | - M A González Ballester
- BCN MedTech, Department of Information and Communication Technologies, Universitat Pompeu Fabra, Barcelona, Spain.,ICREA, Barcelona, Spain
| | - K Wuertz-Kozak
- Department of Health Sciences and Technology, Institute for Biomechanics, ETH Zurich, Zurich, Switzerland.,Department of Biomedical Engineering, Rochester Institute of Technology (RIT), Rochester, NY, United States.,Schön Clinic Munich Harlaching, Spine Center, Academic Teaching Hospital and Spine Research Institute of the Paracelsus Medical University Salzburg (Austria), Munich, Germany
| | - J Noailly
- BCN MedTech, Department of Information and Communication Technologies, Universitat Pompeu Fabra, Barcelona, Spain
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8
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Tobisawa Y, Fujita N, Yamamoto H, Ohyama C, Irie F, Yamaguchi Y. The cell surface hyaluronidase TMEM2 is essential for systemic hyaluronan catabolism and turnover. J Biol Chem 2021; 297:101281. [PMID: 34624311 PMCID: PMC8561002 DOI: 10.1016/j.jbc.2021.101281] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 09/30/2021] [Accepted: 10/01/2021] [Indexed: 11/26/2022] Open
Abstract
As a major component of the extracellular matrix, hyaluronan (HA) plays an important role in defining the biochemical and biophysical properties of tissues. In light of the extremely rapid turnover of HA and the impact of this turnover on HA biology, elucidating the molecular mechanisms underlying HA catabolism is key to understanding the in vivo functions of this unique polysaccharide. Here, we show that TMEM2, a recently identified cell surface hyaluronidase, plays an essential role in systemic HA turnover. Employing induced global Tmem2 knockout mice (Tmem2iKO), we determined the effects of Tmem2 ablation not only on the accumulation of HA in bodily fluids and organs, but also on the process of HA degradation in vivo. Within 3 weeks of tamoxifen-induced Tmem2 ablation, Tmem2iKO mice exhibit pronounced accumulation of HA in circulating blood and various organs, reaching levels as high as 40-fold above levels observed in control mice. Experiments using lymphatic and vascular injection of fluorescent HA tracers demonstrate that ongoing HA degradation in the lymphatic system and the liver is significantly impaired in Tmem2iKO mice. We also show that Tmem2 is strongly expressed in endothelial cells in the subcapsular sinus of lymph nodes and in the liver sinusoid, two primary sites implicated in systemic HA turnover. Our results establish TMEM2 as a physiologically relevant hyaluronidase with an essential role in systemic HA catabolism in vivo, acting primarily on the surface of endothelial cells in the lymph nodes and liver.
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Affiliation(s)
- Yuki Tobisawa
- Human Genetics Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California, USA
| | - Naoki Fujita
- Human Genetics Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California, USA
| | - Hayato Yamamoto
- Human Genetics Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California, USA; Department of Urology, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
| | - Chikara Ohyama
- Department of Urology, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
| | - Fumitoshi Irie
- Human Genetics Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California, USA
| | - Yu Yamaguchi
- Human Genetics Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California, USA.
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9
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Owen PJ, Hangai M, Kaneoka K, Rantalainen T, Belavy DL. Mechanical loading influences the lumbar intervertebral disc. A cross-sectional study in 308 athletes and 71 controls. J Orthop Res 2021; 39:989-997. [PMID: 32691862 DOI: 10.1002/jor.24809] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 05/06/2020] [Accepted: 06/25/2020] [Indexed: 02/04/2023]
Abstract
There is evidence in animal populations that loading and exercise can positively impact the intervertebral disc (IVD). However, there is a paucity of information in humans. We examined the lumbar IVDs in 308 young athletes across six sporting groups (baseball, swimming, basketball, kendo, soccer, and running; mean age 19 years) and 71 nonathletic controls. IVD status was quantified via the ratio of IVD to vertebral body height (IVD hypertrophy) and ratio of signal intensity in the nucleus to that in the annulus signal (IVD nucleus hydration) on sagittal T2-weighted magnetic resonance imaging. P values were adjusted via the false discovery rate method to mitigate false positives. In examining the whole collective, compared to referents, there was evidence of IVD hypertrophy in basketball (P ≤ .029), swimming (P ≤ .010), soccer (P = .036), and baseball (P = .011) with greater IVD nucleus hydration in soccer (P = .007). After matching participants based on back-pain status and body height, basketball players showed evidence of IVD hypertrophy (P ≤ .043) and soccer players greater IVD nucleus hydration (P = .001) than referents. Greater career duration and training volume correlated with less (ie, worse) IVD nucleus hydration, but explained less than 1% of the variance in this parameter. In this young collective, increasing age was associated with increased IVD height. The findings suggest that basketball and soccer may be associated with beneficial adaptations in the IVDs in young athletes. In line with evidence on other tissues, such as muscle and bone, the current study adds to evidence that specific loading types may beneficially modulate lumbar IVD properties.
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Affiliation(s)
- Patrick J Owen
- School of Exercise and Nutrition Sciences, Institute for Physical Activity and Nutrition, Deakin University, Geelong, Victoria, Australia
| | - Mika Hangai
- Department of Orthopaedic Surgery, Sports Medical Center, Japan Institute of Sports Sciences, Tokyo, Japan
| | - Koji Kaneoka
- Faculty of Sport Sciences, Waseda University, Tokorozawa, Japan
| | - Timo Rantalainen
- School of Exercise and Nutrition Sciences, Institute for Physical Activity and Nutrition, Deakin University, Geelong, Victoria, Australia.,Gerontology Research Centre and Faculty of Sport and Health Sciences, University of Jyväskylä, Jyväskylä, Finland
| | - Daniel L Belavy
- School of Exercise and Nutrition Sciences, Institute for Physical Activity and Nutrition, Deakin University, Geelong, Victoria, Australia
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10
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Quantitative assessment of the lumbar intervertebral disc via T2 shows excellent long-term reliability. PLoS One 2021; 16:e0249855. [PMID: 33852631 PMCID: PMC8046347 DOI: 10.1371/journal.pone.0249855] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Accepted: 03/25/2021] [Indexed: 12/05/2022] Open
Abstract
Methodologies for the quantitative assessment of the spine tissues, in particular the intervertebral disc (IVD), have not been well established in terms of long-term reliability. This is required for designing prospective studies. 1H water T2 in the IVD (“T2”) has attained wider use in assessment of the lumbar intervertebral discs via magnetic resonance imaging. The reliability of IVD T2 measurements are yet to be established. IVD T2 was assessed nine times at regular intervals over 368 days on six anatomical slices centred at the lumbar spine using a spin-echo multi-echo sequence in 12 men. To assess repeatability, intra-class correlation co-efficients (ICCs), standard error of the measurement, minimal detectable difference and co-efficients of variation (CVs) were calculated along with their 95% confidence intervals. Bland-Altman analysis was also performed. ICCs were above 0.93, with the exception of nuclear T2 at L5/S1, where the ICC was 0.88. CVs of the central-slice nucleus sub-region ranged from 4.3% (average of all levels) to 10.1% for L5/S1 and between 2.2% to 3.2% for whole IVD T2 (1.8% for the average of all levels). Averaging between vertebral levels improved reliability. Reliability of measurements was least at L5/S1. ICCs of degenerated IVDs were lower. Test-retest reliability was excellent for whole IVD and good to excellent for IVD subregions. The findings help to establish the long-term repeatability of lumbar IVD T2 for the implementation of prospective studies and determination of significant changes within individuals.
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11
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Baumgartner L, Wuertz-Kozak K, Le Maitre CL, Wignall F, Richardson SM, Hoyland J, Ruiz Wills C, González Ballester MA, Neidlin M, Alexopoulos LG, Noailly J. Multiscale Regulation of the Intervertebral Disc: Achievements in Experimental, In Silico, and Regenerative Research. Int J Mol Sci 2021; 22:E703. [PMID: 33445782 PMCID: PMC7828304 DOI: 10.3390/ijms22020703] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 12/22/2020] [Accepted: 12/24/2020] [Indexed: 12/17/2022] Open
Abstract
Intervertebral disc (IVD) degeneration is a major risk factor of low back pain. It is defined by a progressive loss of the IVD structure and functionality, leading to severe impairments with restricted treatment options due to the highly demanding mechanical exposure of the IVD. Degenerative changes in the IVD usually increase with age but at an accelerated rate in some individuals. To understand the initiation and progression of this disease, it is crucial to identify key top-down and bottom-up regulations' processes, across the cell, tissue, and organ levels, in health and disease. Owing to unremitting investigation of experimental research, the comprehension of detailed cell signaling pathways and their effect on matrix turnover significantly rose. Likewise, in silico research substantially contributed to a holistic understanding of spatiotemporal effects and complex, multifactorial interactions within the IVD. Together with important achievements in the research of biomaterials, manifold promising approaches for regenerative treatment options were presented over the last years. This review provides an integrative analysis of the current knowledge about (1) the multiscale function and regulation of the IVD in health and disease, (2) the possible regenerative strategies, and (3) the in silico models that shall eventually support the development of advanced therapies.
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Affiliation(s)
- Laura Baumgartner
- BCN MedTech, Department of Information and Communication Technologies, Universitat Pompeu Fabra, 08018 Barcelona, Spain; (L.B.); (C.R.W.); (M.A.G.B.)
| | - Karin Wuertz-Kozak
- Department of Biomedical Engineering, Rochester Institute of Technology (RIT), Rochester, NY 14623, USA;
- Schön Clinic Munich Harlaching, Spine Center, Academic Teaching Hospital and Spine Research Institute of the Paracelsus Medical University Salzburg (Austria), 81547 Munich, Germany
| | - Christine L. Le Maitre
- Biomolecular Sciences Research Centre, Sheffield Hallam University, Sheffield S1 1WB, UK;
| | - Francis Wignall
- Division of Cell Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Sciences Centre, Oxford Road, Manchester M13 9PT, UK; (F.W.); (S.M.R.); (J.H.)
| | - Stephen M. Richardson
- Division of Cell Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Sciences Centre, Oxford Road, Manchester M13 9PT, UK; (F.W.); (S.M.R.); (J.H.)
| | - Judith Hoyland
- Division of Cell Matrix Biology and Regenerative Medicine, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester Academic Health Sciences Centre, Oxford Road, Manchester M13 9PT, UK; (F.W.); (S.M.R.); (J.H.)
| | - Carlos Ruiz Wills
- BCN MedTech, Department of Information and Communication Technologies, Universitat Pompeu Fabra, 08018 Barcelona, Spain; (L.B.); (C.R.W.); (M.A.G.B.)
| | - Miguel A. González Ballester
- BCN MedTech, Department of Information and Communication Technologies, Universitat Pompeu Fabra, 08018 Barcelona, Spain; (L.B.); (C.R.W.); (M.A.G.B.)
- Catalan Institution for Research and Advanced Studies (ICREA), Pg. Lluis Companys 23, 08010 Barcelona, Spain
| | - Michael Neidlin
- Department of Mechanical Engineering, National Technical University of Athens, 15780 Athens, Greece; (M.N.); (L.G.A.)
| | - Leonidas G. Alexopoulos
- Department of Mechanical Engineering, National Technical University of Athens, 15780 Athens, Greece; (M.N.); (L.G.A.)
| | - Jérôme Noailly
- BCN MedTech, Department of Information and Communication Technologies, Universitat Pompeu Fabra, 08018 Barcelona, Spain; (L.B.); (C.R.W.); (M.A.G.B.)
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12
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Siadat SM, Zamboulis DE, Thorpe CT, Ruberti JW, Connizzo BK. Tendon Extracellular Matrix Assembly, Maintenance and Dysregulation Throughout Life. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1348:45-103. [PMID: 34807415 DOI: 10.1007/978-3-030-80614-9_3] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
In his Lissner Award medal lecture in 2000, Stephen Cowin asked the question: "How is a tissue built?" It is not a new question, but it remains as relevant today as it did when it was asked 20 years ago. In fact, research on the organization and development of tissue structure has been a primary focus of tendon and ligament research for over two centuries. The tendon extracellular matrix (ECM) is critical to overall tissue function; it gives the tissue its unique mechanical properties, exhibiting complex non-linear responses, viscoelasticity and flow mechanisms, excellent energy storage and fatigue resistance. This matrix also creates a unique microenvironment for resident cells, allowing cells to maintain their phenotype and translate mechanical and chemical signals into biological responses. Importantly, this architecture is constantly remodeled by local cell populations in response to changing biochemical (systemic and local disease or injury) and mechanical (exercise, disuse, and overuse) stimuli. Here, we review the current understanding of matrix remodeling throughout life, focusing on formation and assembly during the postnatal period, maintenance and homeostasis during adulthood, and changes to homeostasis in natural aging. We also discuss advances in model systems and novel tools for studying collagen and non-collagenous matrix remodeling throughout life, and finally conclude by identifying key questions that have yet to be answered.
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Affiliation(s)
| | - Danae E Zamboulis
- Institute of Life Course and Medical Sciences, Faculty of Health and Life Sciences, University of Liverpool, Liverpool, UK
| | - Chavaunne T Thorpe
- Comparative Biomedical Sciences, The Royal Veterinary College, University of London, London, UK
| | - Jeffrey W Ruberti
- Department of Bioengineering, Northeastern University, Boston, MA, USA
| | - Brianne K Connizzo
- Department of Biomedical Engineering, Boston University, Boston, MA, USA.
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13
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Abdollah V, Parent EC, Su A, Wachowicz K, Battié MC. Could compression and traction loading improve the ability of magnetic resonance imaging to identify findings related to low back pain? Musculoskelet Sci Pract 2020; 50:102250. [PMID: 32947196 DOI: 10.1016/j.msksp.2020.102250] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 08/22/2020] [Accepted: 08/26/2020] [Indexed: 12/30/2022]
Abstract
BACKGROUND Diagnostic imaging is routinely used to depict structural abnormalities in people with low back pain (LBP), but most findings are prevalent in people with and without LBP. It has been suggested that LBP is related to changes induced in the spine due to loading. Therefore, new imaging measurements are needed to improve our ability to identify structures relating to LBP. OBJECTIVES To investigate the response of the lumbar spine to compression and traction in participants with and without chronic LBP using MRI T2-mapping. METHOD Fifteen participants with chronic LBP were matched for age, weight, and gender with 15 healthy volunteers. All participants underwent MRI under three loading conditions maintained for 20 min each: resting supine, followed by compression and traction, both using 50% body weight. Participants were imaged in the last 5 min of each loading condition. Disc morphometric and fluid-based measurements from T2-maps were obtained. RESULTS Traditional MRI measurements (i.e. disc height, width and mean signal intensity) were not able to capture any differences in the changes measured in response to loading between individuals with and without pain. The location of the T2 weighted centroid (WC) was able to capture the difference between groups in response to compression in the horizontal (p < 0.01) and vertical direction (p < 0.01), and in response to traction in the vertical direction (p < 0.01). While the location of T2WC moved anteriorly (Effect Size (ES): 0.44) and inferiorly with compression in those with pain (ES: 0.34), it moved posteriorly (ES: -0.14) and superiorly (ES: -0.05) in the group without pain. In response to traction, the vertical location of T2WC moved superiorly in both groups but the change was larger in those with pain (ES Pain = -0.52; ES No Pain: -0.13). CONCLUSION The novel measurements of the location of the T2WC in the intervertebral discs were the only measurements capturing differences in response to loading between those with and without low back pain.
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Affiliation(s)
- Vahid Abdollah
- Department of Physical Therapy, Faculty of Rehabilitation Medicine, University of Alberta, 2-50 Corbett Hall, Edmonton, AB, CA T6G 2G4, Canada.
| | - Eric C Parent
- Department of Physical Therapy, Faculty of Rehabilitation Medicine, University of Alberta, 2-50 Corbett Hall, Edmonton, AB, CA T6G 2G4, Canada.
| | - Alex Su
- Department of Physical Therapy, Faculty of Rehabilitation Medicine, University of Alberta, 3-48 Corbett Hall, Edmonton, AB, CA T6G 2G4, Canada.
| | - Keith Wachowicz
- Department of Oncology, Medical Physics Division, 11560 University of Alberta, Edmonton, AB, CA T6G 1Z2, Canada; Department of Medical Physics, Cross Cancer Institute, 11560 University Avenue, Edmonton, AB, CA T6G 1Z2, Canada.
| | - Michele C Battié
- Department of Physical Therapy, Faculty of Rehabilitation Medicine, University of Alberta, 2-50 Corbett Hall, Edmonton, AB, CA T6G 2G4, Canada.
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14
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Wang L, Gu Y, Zhao H, Chen R, Chen W, Qi H, Gao W. Dioscin Attenuates Interleukin 1β (IL-1β)-Induced Catabolism and Apoptosis via Modulating the Toll-Like Receptor 4 (TLR4)/Nuclear Factor kappa B (NF-κB) Signaling in Human Nucleus Pulposus Cells. Med Sci Monit 2020; 26:e923386. [PMID: 32841225 PMCID: PMC7466834 DOI: 10.12659/msm.923386] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Background Nucleus pulposus (NP) cell dysfunction and apoptosis contribute to disc degeneration. Dioscin, a natural steroid saponin, has been demonstrated to have anti-inflammatory, antiapoptotic, and antioxidative effects in various diseases. However, little is known about the roles of dioscin in intervertebral disc degeneration. Material/Methods To evaluate the roles of dioscin in disc degeneration and its specific mechanism, human NP cells were incubated with IL-1β and various concentrations of dioscin. Cell viability, extracellular matrix protein expression, catabolic factors, degree of apoptosis, inflammatory factors, and related signaling pathways were evaluated by western blotting, fluorescence immunostaining, TUNEL staining, and reverse transcription PCR. Results Dioscin inhibited IL-1β-activated apoptotic signaling and catabolic activity in NP cells. Dioscin suppressed TLR4/NF-0κB signaling, and attenuated the level of inflammatory mediators (IL-6, TNF-α) in IL-1β-stimulated human NP cells. Conclusions Our work provides the first evidence that dioscin attenuates IL-1β-activated inflammation and catabolic activity in human NP cells through inhibiting the TLR4/NF-κB pathway, indicating that dioscin is a new potential candidate for clinical therapy to attenuate disc degeneration.
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Affiliation(s)
- Longhui Wang
- Department of Orthopedics, The Second Affiliated Hospital of Hainan Medical University, Haikou, Hainan, China (mainland)
| | - Yuntao Gu
- Department of Orthopedics, The Second Affiliated Hospital of Hainan Medical University, Haikou, Hainan, China (mainland)
| | - Hai Zhao
- Department of Orthopedics, The Second Affiliated Hospital of Hainan Medical University, Haikou, Hainan, China (mainland)
| | - Rong Chen
- Department of Orthopedics, The Second Affiliated Hospital of Hainan Medical University, Haikou, Hainan, China (mainland)
| | - Wensheng Chen
- Department of Orthopedics, The Second Affiliated Hospital of Hainan Medical University, Haikou, Hainan, China (mainland)
| | - Hao Qi
- Department of Orthopedics, The Second Affiliated Hospital of Hainan Medical University, Haikou, Hainan, China (mainland)
| | - Weisong Gao
- Department of Orthopedics, The Second Affiliated Hospital of Hainan Medical University, Haikou, Hainan, China (mainland)
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15
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Choi H, Simpson D, Wang D, Prescott M, Pitsillides AA, Dudhia J, Clegg PD, Ping P, Thorpe CT. Heterogeneity of proteome dynamics between connective tissue phases of adult tendon. eLife 2020; 9:e55262. [PMID: 32393437 PMCID: PMC7217697 DOI: 10.7554/elife.55262] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 04/16/2020] [Indexed: 12/29/2022] Open
Abstract
Maintenance of connective tissue integrity is fundamental to sustain function, requiring protein turnover to repair damaged tissue. However, connective tissue proteome dynamics remain largely undefined, as do differences in turnover rates of individual proteins in the collagen and glycoprotein phases of connective tissue extracellular matrix (ECM). Here, we investigate proteome dynamics in the collagen and glycoprotein phases of connective tissues by exploiting the spatially distinct fascicular (collagen-rich) and interfascicular (glycoprotein-rich) ECM phases of tendon. Using isotope labelling, mass spectrometry and bioinformatics, we calculate turnover rates of individual proteins within rat Achilles tendon and its ECM phases. Our results demonstrate complex proteome dynamics in tendon, with ~1000 fold differences in protein turnover rates, and overall faster protein turnover within the glycoprotein-rich interfascicular matrix compared to the collagen-rich fascicular matrix. These data provide insights into the complexity of proteome dynamics in tendon, likely required to maintain tissue homeostasis.
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Affiliation(s)
- Howard Choi
- Department of Physiology and Medicine, David Geffen School of Medicine, UCLALos AngelesUnited States
| | - Deborah Simpson
- Centre for Proteome Research, Biosciences Building, Institute of Integrative Biology, University of LiverpoolLiverpoolUnited Kingdom
| | - Ding Wang
- Department of Physiology and Medicine, David Geffen School of Medicine, UCLALos AngelesUnited States
| | - Mark Prescott
- Centre for Proteome Research, Biosciences Building, Institute of Integrative Biology, University of LiverpoolLiverpoolUnited Kingdom
| | - Andrew A Pitsillides
- Department of Comparative Biomedical Sciences, Royal Veterinary CollegeLondonUnited Kingdom
| | - Jayesh Dudhia
- Department of Clinical Sciences and Services, Royal Veterinary CollegeHatfieldUnited Kingdom
| | - Peter D Clegg
- Department of Musculoskeletal Biology, Institute of Ageing and Chronic Disease, University of LiverpoolLiverpoolUnited Kingdom
| | - Peipei Ping
- Department of Physiology and Medicine, David Geffen School of Medicine, UCLALos AngelesUnited States
| | - Chavaunne T Thorpe
- Department of Comparative Biomedical Sciences, Royal Veterinary CollegeLondonUnited Kingdom
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16
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Exercise for the intervertebral disc: a 6-month randomised controlled trial in chronic low back pain. EUROPEAN SPINE JOURNAL : OFFICIAL PUBLICATION OF THE EUROPEAN SPINE SOCIETY, THE EUROPEAN SPINAL DEFORMITY SOCIETY, AND THE EUROPEAN SECTION OF THE CERVICAL SPINE RESEARCH SOCIETY 2020; 29:1887-1899. [PMID: 32211998 DOI: 10.1007/s00586-020-06379-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 02/12/2020] [Accepted: 03/14/2020] [Indexed: 01/19/2023]
Abstract
BACKGROUND CONTEXT Muscle, bone and tendon respond anabolically to mechanical forces. Whether the intervertebral disc (IVD) can benefit from exercise is unclear. PURPOSE To examine whether exercise can beneficially affect IVD characteristics. STUDY DESIGN/SETTING This is a single-blinded 6-month randomised controlled trial (ACTRN12615001270505) in an exercise and physiotherapy clinic. PATIENT SAMPLE Forty patients with chronic non-specific low back pain (NSCLBP) are included in this study. OUTCOME MEASURES The primary outcome was lumbar IVD T2 time (MRI). Secondary outcomes included IVD diffusion coefficient and IVD expansion with short-duration lying. METHODS Twenty patients progressively loaded their lumbar IVDs (exercise) via an exercise programme involving progressive upright aerobic and resistance exercises targeting the trunk and major muscle groups and were compared to twenty patients who performed motor control training and manual therapy (control). Testing occurred at baseline, 3 months and 6 months. RESULTS Seventeen exercise and fifteen control patients completed the interventions. There were no group-by-time differences in T2 time of the entire IVD (exercise 94.1 ± 10.0 ms vs. control 96.5 ± 9.3 ms, p = 0.549). Exercise patients had shorter T2 time in the posterior annulus at 6 months (82.7 ± 6.8 ms vs. 85.1 ± 8.0 ms, p = 0.028). Exercise patients showed higher L5/S1 apparent diffusion coefficients and decreased IVD height at 3 months (both p ≤ 0.050). After adjustments for multiple comparisons, differences lost statistical significance. Per-protocol and intent-to-treat analyses yielded similar findings. CONCLUSIONS This trial found that 6 months of exercise did not benefit the IVD of people with NSCLBP. Based on this index study, future studies could investigate the effect of exercise on IVD in different populations, with different types, durations and/or intensities of exercise, and using different IVD markers. These slides can be retrieved under Electronic Supplementary Material.
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17
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Degeneration of Lumbar Intervertebral Discs: Characterization of Anulus Fibrosus Tissue and Cells of Different Degeneration Grades. Int J Mol Sci 2020; 21:ijms21062165. [PMID: 32245213 PMCID: PMC7139657 DOI: 10.3390/ijms21062165] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 03/18/2020] [Accepted: 03/19/2020] [Indexed: 01/16/2023] Open
Abstract
Intervertebral disc (IVD) herniation and degeneration is a major source of back pain. In order to regenerate a herniated and degenerated disc, closure of the anulus fibrosus (AF) is of crucial importance. For molecular characterization of AF, genome-wide Affymetrix HG-U133plus2.0 microarrays of native AF and cultured cells were investigated. To evaluate if cells derived from degenerated AF are able to initiate gene expression of a regenerative pattern of extracellular matrix (ECM) molecules, cultivated cells were stimulated with bone morphogenetic protein 2 (BMP2), transforming growth factor β1 (TGFβ1) or tumor necrosis factor-α (TNFα) for 24 h. Comparative microarray analysis of native AF tissues showed 788 genes with a significantly different gene expression with 213 genes more highly expressed in mild and 575 genes in severe degenerated AF tissue. Mild degenerated native AF tissues showed a higher gene expression of common cartilage ECM genes, whereas severe degenerated AF tissues expressed genes known from degenerative processes, including matrix metalloproteinases (MMP) and bone associated genes. During monolayer cultivation, only 164 differentially expressed genes were found. The cells dedifferentiated and altered their gene expression profile. RTD-PCR analyses of BMP2- and TGFβ1-stimulated cells from mild and severe degenerated AF tissue after 24 h showed an increased expression of cartilage associated genes. TNFα stimulation increased MMP1, 3, and 13 expression. Cells derived from mild and severe degenerated tissues could be stimulated to a comparable extent. These results give hope that regeneration of mildly but also strongly degenerated disc tissue is possible.
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18
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Effect of intervertebral disc degeneration on mechanical and electric signals at the interface between disc and vertebra. J Biomech 2020; 104:109756. [PMID: 32248941 DOI: 10.1016/j.jbiomech.2020.109756] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Revised: 01/30/2020] [Accepted: 03/13/2020] [Indexed: 11/23/2022]
Abstract
Intervertebral disc (IVD) degeneration is significantly correlated with the changes in structure and material properties of adjacent vertebral bone, possibly through mechanical and electrical interactions. However, the mechanisms underlying the alteration of the mechanical and electrical environment at the disc-vertebra interface related with disc degeneration have not been well studied. The objective of this study was to numerically investigate the long-term distributions of mechanical and electrical signals on the disc-vertebra interface with disc degeneration. A three-dimensional finite element model of a human lumbar IVD was used to study the mechanical and electric signals at the interface between disc and vertebral body. The disc degeneration was simulated by reducing the nutrition levels on the nucleus pulposus (NP)-vertebra interface and on the annulus fibrosus (AF) periphery to 30% and 60% of its normal values, respectively. In the simulation, the total external mechanical load applied to the disc-vertebra segment was assumed unchanged during disc degeneration. The simulation results showed that the compressive stress of solid matrix changed by up to ~37 kPa on the NP-vertebra interface, while it increased by up to ~32 kPa on the AF-vertebra interface. The shear stress increased by up to ~37 kPa with disc degeneration. The absolute value of the electric potential on the disc-vertebra interface of the disc slightly decreased with the disc degeneration (~0.5 mV). The knowledge of these spatial and temporal variations of the mechanical stresses and electric potential on the disc-vertebra interface is important for understanding the vertebrae adaptation and remodeling during disc degeneration.
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19
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Song Y, Wang Z, Liu L, Zhang S, Zhang H, Qian Y. 1,4-Dihydropyridine (DHP) suppresses against oxidative stress in nucleus pulposus via activating sirtuin-1. Biomed Pharmacother 2019; 121:109592. [PMID: 31706101 DOI: 10.1016/j.biopha.2019.109592] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Revised: 10/23/2019] [Accepted: 10/26/2019] [Indexed: 01/03/2023] Open
Abstract
Intervertebral disc degeneration (IVDD) is a major cause of many spinal diseases characterized mainly by nucleus pulposus degradation. 1,4-dihydropyridine (DHP), a new activator of sirtuin-1 (sirt1), has been reported to have anti-oxidative effects. The aim of this study is to investigate the effect of DHP on nucleus pulposus (NP) cells in vitro. NP cells were pretreated with IL-1β to establish a degenerated model, and then treated with DHP alone or DHP combined with selisistat (an inhibitor of sirt1). ROS level was analyzed by flow cytometry. Production of IL-6 and TNF-α were evaluated by the enzyme-linked immunosorbent assay (ELISA). The mRNA and protein expression were measured by quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot respectively. Immunofluorescence was used to assess the expression of collagen-II and sirt1. We found that DHP inhibited IL-1β-induced upregulation of ROS, TNF-α, IL-6, MMP-3, ADAMTS-5. Besides, DHP remarkably increased the sirt1 and anti-oxidative protein SOD-1 level. Furthermore, DHP significantly protected the IL-1β-induced degradation of collagen-II and aggrecan. However, the inhibitory effect of DHP was obvious abolished by selisistat, suggesting that DHP exerts these effects in NP cells through activating sirt1. Taken together, we found that DHP inhibited the ROS, inflammatory response and ECM degradation through activating Sirt1 in human NP cells.
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Affiliation(s)
- Yuxin Song
- Department of Orthopaedics, Gansu Provincial Hospital, Lanzhou, Gansu, China
| | - Zhan Wang
- Department of Orthopaedics, Gansu Provincial Hospital, Lanzhou, Gansu, China
| | - Lin Liu
- Department of Orthopaedics, Gansu Provincial Hospital, Lanzhou, Gansu, China
| | - Suifeng Zhang
- Department of Orthopaedics, Gansu Provincial Hospital, Lanzhou, Gansu, China
| | - Hui Zhang
- Department of Orthopaedics, Gansu Provincial Hospital, Lanzhou, Gansu, China
| | - Yaowen Qian
- Department of Orthopaedics, Gansu Provincial Hospital, Lanzhou, Gansu, China; Cancer Center, Gansu Provincial Hospital, Lanzhou, Gansu, China.
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20
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Hsueh MF, Önnerfjord P, Bolognesi MP, Easley ME, Kraus VB. Analysis of "old" proteins unmasks dynamic gradient of cartilage turnover in human limbs. SCIENCE ADVANCES 2019; 5:eaax3203. [PMID: 31633025 PMCID: PMC6785252 DOI: 10.1126/sciadv.aax3203] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Accepted: 09/10/2019] [Indexed: 05/23/2023]
Abstract
Unlike highly regenerative animals, such as axolotls, humans are believed to be unable to counteract cumulative damage, such as repetitive joint use and injury that lead to the breakdown of cartilage and the development of osteoarthritis. Turnover of insoluble collagen has been suggested to be very limited in human adult cartilage. The goal of this study was to explore protein turnover in articular cartilage from human lower limb joints. Analyzing molecular clocks in the form of nonenzymatically deamidated proteins, we unmasked a position-dependent gradient (distal high, proximal low) of protein turnover, indicative of a gradient of tissue anabolism reflecting innate tissue repair capacity in human lower limb cartilages that is associated with expression of limb-regenerative microRNAs. This association shows a potential link to a capacity, albeit limited, for regeneration that might be exploited to enhance joint repair and establish a basis for human limb regeneration.
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Affiliation(s)
- Ming-Feng Hsueh
- Duke Molecular Physiology Institute, Duke University School of Medicine, Durham, NC, USA
- Department of Orthopaedic Surgery, Duke University Medical Center, Durham, NC, USA
| | | | - Michael P. Bolognesi
- Department of Orthopaedic Surgery, Duke University Medical Center, Durham, NC, USA
| | - Mark E. Easley
- Department of Orthopaedic Surgery, Duke University Medical Center, Durham, NC, USA
| | - Virginia B. Kraus
- Duke Molecular Physiology Institute, Duke University School of Medicine, Durham, NC, USA
- Division of Rheumatology, Department of Medicine, Duke University School of Medicine, Durham, NC, USA
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21
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Hayes AJ, Melrose J. Glycosaminoglycan and Proteoglycan Biotherapeutics in Articular Cartilage Protection and Repair Strategies: Novel Approaches to Visco‐supplementation in Orthobiologics. ADVANCED THERAPEUTICS 2019. [DOI: 10.1002/adtp.201900034] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Anthony J. Hayes
- Bioimaging Research HubCardiff School of BiosciencesCardiff University Cardiff CF10 3AX Wales UK
| | - James Melrose
- Graduate School of Biomedical EngineeringUNSW Sydney Sydney NSW 2052 Australia
- Raymond Purves Bone and Joint Research LaboratoriesKolling Institute of Medical ResearchRoyal North Shore Hospital and The Faculty of Medicine and HealthUniversity of Sydney St. Leonards NSW 2065 Australia
- Sydney Medical SchoolNorthernRoyal North Shore HospitalSydney University St. Leonards NSW 2065 Australia
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22
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Holzer T, Probst K, Etich J, Auler M, Georgieva VS, Bluhm B, Frie C, Heilig J, Niehoff A, Nüchel J, Plomann M, Seeger JM, Kashkar H, Baris OR, Wiesner RJ, Brachvogel B. Respiratory chain inactivation links cartilage-mediated growth retardation to mitochondrial diseases. J Cell Biol 2019; 218:1853-1870. [PMID: 31085560 PMCID: PMC6548139 DOI: 10.1083/jcb.201809056] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Revised: 01/12/2019] [Accepted: 04/12/2019] [Indexed: 12/17/2022] Open
Abstract
Children with mitochondrial diseases often present with slow growth and short stature, but the underlying mechanism remains unclear. In this study, Holzer et al. provide in vivo evidence that mitochondrial respiratory chain dysfunction induces cartilage degeneration coincident with altered metabolism, impaired extracellular matrix formation, and cell death at the cartilage–bone junction. In childhood, skeletal growth is driven by transient expansion of cartilage in the growth plate. The common belief is that energy production in this hypoxic tissue mainly relies on anaerobic glycolysis and not on mitochondrial respiratory chain (RC) activity. However, children with mitochondrial diseases causing RC dysfunction often present with short stature, which indicates that RC activity may be essential for cartilage-mediated skeletal growth. To elucidate the role of the mitochondrial RC in cartilage growth and pathology, we generated mice with impaired RC function in cartilage. These mice develop normally until birth, but their later growth is retarded. A detailed molecular analysis revealed that metabolic signaling and extracellular matrix formation is disturbed and induces cell death at the cartilage–bone junction to cause a chondrodysplasia-like phenotype. Hence, the results demonstrate the overall importance of the metabolic switch from fetal glycolysis to postnatal RC activation in growth plate cartilage and explain why RC dysfunction can cause short stature in children with mitochondrial diseases.
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Affiliation(s)
- Tatjana Holzer
- Department of Pediatrics and Adolescent Medicine, Experimental Neonatology, Faculty of Medicine, University of Cologne, Cologne, Germany.,Center for Biochemistry, Faculty of Medicine, University of Cologne, Cologne, Germany
| | - Kristina Probst
- Department of Pediatrics and Adolescent Medicine, Experimental Neonatology, Faculty of Medicine, University of Cologne, Cologne, Germany.,Center for Biochemistry, Faculty of Medicine, University of Cologne, Cologne, Germany
| | - Julia Etich
- Department of Pediatrics and Adolescent Medicine, Experimental Neonatology, Faculty of Medicine, University of Cologne, Cologne, Germany.,Center for Biochemistry, Faculty of Medicine, University of Cologne, Cologne, Germany
| | - Markus Auler
- Department of Pediatrics and Adolescent Medicine, Experimental Neonatology, Faculty of Medicine, University of Cologne, Cologne, Germany.,Center for Biochemistry, Faculty of Medicine, University of Cologne, Cologne, Germany
| | - Veronika S Georgieva
- Department of Pediatrics and Adolescent Medicine, Experimental Neonatology, Faculty of Medicine, University of Cologne, Cologne, Germany.,Center for Biochemistry, Faculty of Medicine, University of Cologne, Cologne, Germany
| | - Björn Bluhm
- Department of Pediatrics and Adolescent Medicine, Experimental Neonatology, Faculty of Medicine, University of Cologne, Cologne, Germany.,Center for Biochemistry, Faculty of Medicine, University of Cologne, Cologne, Germany
| | - Christian Frie
- Department of Pediatrics and Adolescent Medicine, Experimental Neonatology, Faculty of Medicine, University of Cologne, Cologne, Germany.,Center for Biochemistry, Faculty of Medicine, University of Cologne, Cologne, Germany
| | - Juliane Heilig
- Institute of Biomechanics and Orthopedics, German Sport University Cologne, Cologne, Germany.,Cologne Center for Musculoskeletal Biomechanics, University of Cologne, Cologne, Germany
| | - Anja Niehoff
- Institute of Biomechanics and Orthopedics, German Sport University Cologne, Cologne, Germany.,Cologne Center for Musculoskeletal Biomechanics, University of Cologne, Cologne, Germany
| | - Julian Nüchel
- Center for Biochemistry, Faculty of Medicine, University of Cologne, Cologne, Germany
| | - Markus Plomann
- Center for Biochemistry, Faculty of Medicine, University of Cologne, Cologne, Germany
| | - Jens M Seeger
- Institute for Medical Microbiology, Immunology, and Hygiene, Faculty of Medicine, University of Cologne, Cologne, Germany
| | - Hamid Kashkar
- Institute for Medical Microbiology, Immunology, and Hygiene, Faculty of Medicine, University of Cologne, Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, University of Cologne, Cologne, Germany.,Center of Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Olivier R Baris
- Center for Physiology and Pathophysiology, Institute of Vegetative Physiology, Faculty of Medicine, University of Cologne, Cologne, Germany
| | - Rudolf J Wiesner
- Center for Physiology and Pathophysiology, Institute of Vegetative Physiology, Faculty of Medicine, University of Cologne, Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases, University of Cologne, Cologne, Germany.,Center of Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Bent Brachvogel
- Department of Pediatrics and Adolescent Medicine, Experimental Neonatology, Faculty of Medicine, University of Cologne, Cologne, Germany .,Center for Biochemistry, Faculty of Medicine, University of Cologne, Cologne, Germany
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Emanuel KS, Mader KT, Peeters M, Kingma I, Rustenburg CME, Vergroesen PPA, Sammon C, Smit TH. Early changes in the extracellular matrix of the degenerating intervertebral disc, assessed by Fourier transform infrared imaging. Osteoarthritis Cartilage 2018; 26:1400-1408. [PMID: 29935308 DOI: 10.1016/j.joca.2018.06.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Revised: 05/09/2018] [Accepted: 06/07/2018] [Indexed: 02/02/2023]
Abstract
OBJECTIVE Mechanical overloading induces a degenerative cell response in the intervertebral disc. However, early changes in the extracellular matrix (ECM) are challenging to assess with conventional techniques. Fourier Transform Infrared (FTIR) imaging allows visualization and quantification of the ECM. We aim to identify markers for disc degeneration and apply these to investigate early degenerative changes due to overloading and katabolic cell activity. DESIGN Three experiments were conducted; Exp 1.: In vivo, lumbar spines of seven goats were operated: one disc was injected with chondroitinase ABC [cABC (mild degeneration)] and compared to the adjacent disc (control) after 24 weeks. Exp 2a: Ex vivo, caprine discs received physiological loading (n = 10) or overloading (n = 10) in a bioreactor. Exp 2b: Cell activity was diminished prior to testing by freeze-thaw cycles, 18 discs were then tested as in Exp 2a. In all experiments, FTIR images (spectral region: 1000-1300 cm-1) of mid-sagittal slices were analyzed using multivariate curve resolution. RESULTS In vivo, FTIR was more sensitive than biochemical and histological analysis in identifying reduced proteoglycan content (P = 0.046) and increased collagen content in degenerated discs (P < 0.01). Notably, FTIR analysis additionally showed disorganization of the ECM, indicated by increased collagen entropy (P = 0.011). Ex vivo, the proteoglycan/collagen ratio decreased due to overloading (P = 0.047) and collagen entropy increased (P = 0.047). Cell activity affected collagen content only (P = 0.044). CONCLUSION FTIR imaging allows a more detailed investigation of early disc degeneration than traditional measures. Changes due to mild overloading could be assessed and quantified. Matrix remodeling is the first detectable step towards intervertebral disc degeneration.
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Affiliation(s)
- K S Emanuel
- Department of Orthopaedic Surgery, Academic Medical Center, University of Amsterdam, Amsterdam Movement Sciences, Amsterdam, The Netherlands; Department of Orthopedic Surgery, VU University Medical Center, Amsterdam Movement Sciences, The Netherlands.
| | - K T Mader
- Materials and Engineering Research Institute, Sheffield Hallam University, Sheffield, UK.
| | - M Peeters
- Department of Orthopedic Surgery, VU University Medical Center, Amsterdam Movement Sciences, The Netherlands.
| | - I Kingma
- Department of Human Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, The Netherlands.
| | - C M E Rustenburg
- Department of Orthopaedic Surgery, Academic Medical Center, University of Amsterdam, Amsterdam Movement Sciences, Amsterdam, The Netherlands; Department of Orthopedic Surgery, VU University Medical Center, Amsterdam Movement Sciences, The Netherlands.
| | - P-P A Vergroesen
- Department of Orthopedic Surgery, VU University Medical Center, Amsterdam Movement Sciences, The Netherlands; Department of Orthopaedic Surgery, NoordWest Ziekenhuisgroep, Alkmaar, The Netherlands.
| | - C Sammon
- Materials and Engineering Research Institute, Sheffield Hallam University, Sheffield, UK.
| | - T H Smit
- Department of Orthopaedic Surgery, Academic Medical Center, University of Amsterdam, Amsterdam Movement Sciences, Amsterdam, The Netherlands; Department of Medical Biology, Academic Medical Center, University of Amsterdam, Amsterdam Movement Sciences, Amsterdam, The Netherlands.
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Comparison of patient-specific computational models vs. clinical follow-up, for adjacent segment disc degeneration and bone remodelling after spinal fusion. PLoS One 2018; 13:e0200899. [PMID: 30161138 PMCID: PMC6116979 DOI: 10.1371/journal.pone.0200899] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Accepted: 07/04/2018] [Indexed: 11/21/2022] Open
Abstract
Spinal fusion is a standard surgical treatment for patients suffering from low back pain attributed to disc degeneration. However, results are somewhat variable and unpredictable. With fusion the kinematic behaviour of the spine is altered. Fusion and/or stabilizing implants carrying considerable load and prevent rotation of the fused segments. Associated with these changes, a risk for accelerated disc degeneration at the adjacent levels to fusion has been demonstrated. However, there is yet no method to predict the effect of fusion surgery on the adjacent tissue levels, i.e. bone and disc. The aim of this study was to develop a coupled and patient-specific mechanoregulated model to predict disc generation and changes in bone density after spinal fusion and to validate the results relative to patient follow-up data. To do so, a multiscale disc mechanoregulation adaptation framework was developed and coupled with a previously developed bone remodelling algorithm. This made it possible to determine extra cellular matrix changes in the intervertebral disc and bone density changes simultaneously based on changes in loading due to fusion surgery. It was shown that for 10 cases the predicted change in bone density and degeneration grade conforms reasonable well to clinical follow-up data. This approach helps us to understand the effect of surgical intervention on the adjacent tissue remodelling. Thereby, providing the first insight for a spine surgeon as to which patient could potentially be treated successfully by spinal fusion and in which patient has a high risk for adjacent tissue changes.
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Lupeol against high-glucose-induced apoptosis via enhancing the anti-oxidative stress in rabbit nucleus pulposus cells. 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 2018; 27:2609-2620. [DOI: 10.1007/s00586-018-5687-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Revised: 05/19/2018] [Accepted: 06/25/2018] [Indexed: 01/05/2023]
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Abstract
The extracellular matrix (ECM) provides the environment for many cells types within the body and, in addition to the well recognised role as a structural support, influences many important cell process within the body. As a result, age-related changes to the proteins of the ECM have far reaching consequences with the potential to disrupt many different aspects of homeostasis and healthy function. The proteins collagen and elastin are the most abundant in the ECM and their ability to function as a structural support and provide mechanical stability results from the formation of supra-molecular structures. Collagen and elastin have a long half-life, as required by their structural role, which leaves them vulnerable to a range of post-translational modifications. In this chapter the role of the ECM is discussed and the component proteins introduced. Major age-related modifications including glycation, carbamylation and fragmentation and the impact these have on ECM function are reviewed.
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Hua WB, Wu XH, Zhang YK, Song Y, Tu J, Kang L, Zhao KC, Li S, Wang K, Liu W, Shao ZW, Yang SH, Yang C. Dysregulated miR-127-5p contributes to type II collagen degradation by targeting matrix metalloproteinase-13 in human intervertebral disc degeneration. Biochimie 2017; 139:74-80. [PMID: 28559201 DOI: 10.1016/j.biochi.2017.05.018] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Accepted: 05/25/2017] [Indexed: 12/31/2022]
Abstract
BACKGROUND Intervertebral disc degeneration (IDD) is a chronic disease associated with the degradation of extracellular matrix (ECM). Matrix metalloproteinase (MMP)-13 is a major enzyme that mediates the degradation of ECM components. MMP-13 has been predicted to be a potential target of miR-127-5p. However, the exact function of miR-127-5p in IDD is still unclear. OBJECTIVE We designed this study to evaluate the correlation between miR-127-5p level and the degeneration of human intervertebral discs and explore the potential mechanisms. METHODS miR-127-5p levels and MMP-13 mRNA levels were detected by quantitative real-time polymerase chain reaction (qPCR). To determine whether MMP-13 is a target of miR-127-5p, dual luciferase reporter assays were performed. miR-127-5p mimic and miR-127-5p inhibitor were used to overexpress or downregulate miR-127-5p expression in human NP cells, respectively. Small interfering RNA (siRNA) was used to knock down MMP-13 expression in human NP cells. Type II collagen expression in human NP cells was detected by qPCR, western blotting, and immunofluorescence staining. RESULTS We confirmed that miR-127-5p was significantly downregulated in nucleus pulposus (NP) tissue of degenerative discs and its expression was inversely correlated with MMP-13 mRNA levels. We reveal that MMP-13 may act as a target of miR-127-5p. Expression of miR-127-5p was inversely correlated with type II collagen expression in human NP cells. Moreover, suppression of MMP-13 expression by siRNA blocked downstream signaling and increased type II collagen expression. CONCLUSION Dysregulated miR-127-5p contributed to the degradation of type II collagen by targeting MMP-13 in human IDD. Our findings highlight that miR-127-5p may serve as a new therapeutic target in IDD.
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Affiliation(s)
- Wen-Bin Hua
- Department of Orthopaedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1277 Jiefang Avenue, Wuhan 430022, China
| | - Xing-Huo Wu
- Department of Orthopaedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1277 Jiefang Avenue, Wuhan 430022, China
| | - Yu-Kun Zhang
- Department of Orthopaedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1277 Jiefang Avenue, Wuhan 430022, China
| | - Yu Song
- Department of Orthopaedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1277 Jiefang Avenue, Wuhan 430022, China
| | - Ji Tu
- Department of Orthopaedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1277 Jiefang Avenue, Wuhan 430022, China
| | - Liang Kang
- Department of Orthopaedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1277 Jiefang Avenue, Wuhan 430022, China
| | - Kang-Cheng Zhao
- Department of Orthopaedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1277 Jiefang Avenue, Wuhan 430022, China
| | - Shuai Li
- Department of Orthopaedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1277 Jiefang Avenue, Wuhan 430022, China
| | - Kun Wang
- Department of Orthopaedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1277 Jiefang Avenue, Wuhan 430022, China
| | - Wei Liu
- Department of Orthopaedics, Wuhan No.1 Hospital, 215 Zhongshan Avenue, Wuhan 430022, China
| | - Zeng-Wu Shao
- Department of Orthopaedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1277 Jiefang Avenue, Wuhan 430022, China
| | - Shu-Hua Yang
- Department of Orthopaedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1277 Jiefang Avenue, Wuhan 430022, China
| | - Cao Yang
- Department of Orthopaedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1277 Jiefang Avenue, Wuhan 430022, China.
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Running exercise strengthens the intervertebral disc. Sci Rep 2017; 7:45975. [PMID: 28422125 PMCID: PMC5396190 DOI: 10.1038/srep45975] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Accepted: 03/07/2017] [Indexed: 11/17/2022] Open
Abstract
There is currently no evidence that the intervertebral discs (IVDs) can respond positively to exercise in humans. Some authors have argued that IVD metabolism in humans is too slow to respond anabolically to exercise within the human lifespan. Here we show that chronic running exercise in men and women is associated with better IVD composition (hydration and proteoglycan content) and with IVD hypertrophy. Via quantitative assessment of physical activity we further find that accelerations at fast walking and slow running (2 m/s), but not high-impact tasks, lower intensity walking or static positions, correlated to positive IVD characteristics. These findings represent the first evidence in humans that exercise can be beneficial for the IVD and provide support for the notion that specific exercise protocols may improve IVD material properties in the spine. We anticipate that our findings will be a starting point to better define exercise protocols and physical activity profiles for IVD anabolism in humans.
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Contaminants in commercial preparations of 'purified' small leucine-rich proteoglycans may distort mechanistic studies. Biosci Rep 2017; 37:BSR20160465. [PMID: 27994047 PMCID: PMC5234103 DOI: 10.1042/bsr20160465] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Revised: 12/14/2016] [Accepted: 12/19/2016] [Indexed: 12/24/2022] Open
Abstract
The present study reports the perplexing results that came about because of seriously impure commercially available reagents. Commercial reagents and chemicals are routinely ordered by scientists and expected to have been rigorously assessed for their purity. Unfortunately, we found this assumption to be risky. Extensive work was carried out within our laboratory using commercially sourced preparations of the small leucine-rich proteoglycans (SLRPs), decorin and biglycan, to investigate their influence on nerve cell growth. Unusual results compelled us to analyse the composition and purity of both preparations of these proteoglycans (PGs) using both mass spectrometry (MS) and Western blotting, with and without various enzymatic deglycosylations. Commercial ‘decorin’ and ‘biglycan’ were found to contain a mixture of PGs including not only both decorin and biglycan but also fibromodulin and aggrecan. The unexpected effects of ‘decorin’ and ‘biglycan’ on nerve cell growth could be explained by these impurities. Decorin and biglycan contain either chondroitin or dermatan sulfate glycosaminoglycan (GAG) chains whereas fibromodulin only contains keratan sulfate and the large (>2500 kDa), highly glycosylated aggrecan contains both keratan and chondroitin sulfate. The different structure, molecular weight and composition of these impurities significantly affected our work and any conclusions that could be made. These findings beg the question as to whether scientists need to verify the purity of each commercially obtained reagent used in their experiments. The implications of these findings are vast, since the effects of these impurities may already have led to inaccurate conclusions and reports in the literature with concomitant loss of researchers’ funds and time.
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The Involvement of Protease Nexin-1 (PN1) in the Pathogenesis of Intervertebral Disc (IVD) Degeneration. Sci Rep 2016; 6:30563. [PMID: 27460424 PMCID: PMC4962060 DOI: 10.1038/srep30563] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Accepted: 07/06/2016] [Indexed: 01/02/2023] Open
Abstract
Protease nexin-1 (PN-1) is a serine protease inhibitor belonging to the serpin superfamily. This study was undertaken to investigate the regulatory role of PN-1 in the pathogenesis of intervertebral disk (IVD) degeneration. Expression of PN-1 was detected in human IVD tissue of varying grades. Expression of both PN-1 mRNA and protein was significantly decreased in degenerated IVD, and the expression levels of PN-1 were correlated with the grade of disc degeneration. Moreover, a decrease in PN-1 expression in primary NP cells was confirmed. On induction by IL-1β, the expression of PN-1 in NP cells was decreased at day 7, 14, and 21, as shown by western blot analysis and immunofluorescence staining. PN-1 administration decreased IL-1β-induced MMPs and ADAMTS production and the loss of Agg and Col II in NP cell cultures through the ERK1/2/NF-kB signaling pathway. The changes in PN-1 expression are involved in the pathogenesis of IVD degeneration. Our findings indicate that PN-1 administration could antagonize IL-1β-induced MMPs and ADAMTS, potentially preventing degeneration of IVD tissue. This study also revealed new insights into the regulation of PN-1 expression via the ERK1/2/NF-kB signaling pathway and the role of PN-1 in the pathogenesis of IVD degeneration.
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Tiku ML, Madhan B. Preserving the longevity of long-lived type II collagen and its implication for cartilage therapeutics. Ageing Res Rev 2016; 28:62-71. [PMID: 27133944 DOI: 10.1016/j.arr.2016.04.011] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Accepted: 04/26/2016] [Indexed: 11/30/2022]
Abstract
Human life expectancy has been steadily increasing at a rapid rate, but this increasing life span also brings about increases in diseases, dementia, and disability. A global burden of disease 2010 study revealed that hip and knee osteoarthritis ranked the 11th highest in terms of years lived with disability. Wear and tear can greatly influence the quality of life during ageing. In particular, wear and tear of the articular cartilage have adverse effects on joints and result in osteoarthritis. The articular cartilage uses longevity of type II collagen as the foundation around which turnover of proteoglycans and the homeostatic activity of chondrocytes play central roles thereby maintaining the function of articular cartilage in the ageing. The longevity of type II collagen involves a complex interaction of the scaffolding needs of the cartilage and its biochemical, structural and mechanical characteristics. The covalent cross-linking of heterotypic polymers of collagens type II, type IX and type XI hold together cartilage, allowing it to withstand ageing stresses. Discerning the biological clues in the armamentarium for preserving cartilage appears to be collagen cross-linking. Therapeutic methods to crosslink in in-vivo are non-existent. However intra-articular injections of polyphenols in vivo stabilize the cartilage and make it resistant to degradation, opening a new therapeutic possibility for prevention and intervention of cartilage degradation in osteoarthritis of aging.
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Affiliation(s)
- Moti L Tiku
- Rutgers, Robert Wood Johnson Medical School, New Brunswick, NJ, USA.
| | - Balaraman Madhan
- Council of Scientific and Industrial Research - Central Leather Research Institute, Adyar, Chennai, Tamil Nadu, India
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Zhu Q, Gao X, Temple HT, Brown MD, Gu W. Simulation of biological therapies for degenerated intervertebral discs. J Orthop Res 2016; 34:699-708. [PMID: 26425965 PMCID: PMC4833445 DOI: 10.1002/jor.23061] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/01/2015] [Accepted: 09/25/2015] [Indexed: 02/04/2023]
Abstract
The efficacy of biological therapies on intervertebral disc repair was quantitatively studied using a three-dimensional finite element model based on a cell-activity coupled multiphasic mixture theory. In this model, cell metabolism and matrix synthesis and degradation were considered. Three types of biological therapies-increasing the cell density (Case I), increasing the glycosaminoglycan (GAG) synthesis rate (Case II), and decreasing the GAG degradation rate (Case III)-to the nucleus pulposus (NP) of each of two degenerated discs [one mildly degenerated (e.g., 80% viable cells in the NP) and one severely degenerated (e.g., 30% viable cells in the NP)] were simulated. Degenerated discs without treatment were also simulated as a control. The cell number needed, nutrition level demanded, time required for the repair, and the long-term outcomes of these therapies were analyzed. For Case I, the repair process was predicted to be dependent on the cell density implanted and the nutrition level at disc boundaries. With sufficient nutrition supply, this method was predicted to be effective for treating both mildly and severely degenerated discs. For Case II, the therapy was predicted to be effective for repairing the mildly degenerated disc, but not for the severely degenerated disc. Similar results were predicted for Case III. No change in cell density for Cases II and III were predicted under normal nutrition level. This study provides a quantitative guide for choosing proper strategies of biological therapies for different degenerated discs.
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Affiliation(s)
- Qiaoqiao Zhu
- Dept. of Biomedical Engineering, University of Miami, Coral Gables, FL
| | - Xin Gao
- Dept. of Mechanical and Aerospace Engineering, University of Miami, Coral Gables, FL
| | - H. Thomas Temple
- Dept. of Orthopaedic Surgery, NOVA Southeastern University, Fort Lauderdale, FL
| | - Mark D. Brown
- Dept. of Orthopaedics, University of Miami, Miami, FL
| | - Weiyong Gu
- Dept. of Biomedical Engineering, University of Miami, Coral Gables, FL,Dept. of Mechanical and Aerospace Engineering, University of Miami, Coral Gables, FL,Corresponding author: Weiyong Gu, PhD, 1251 Memorial Drive, MEB206, Coral Gables, FL 33124-0624, 305-284-8553, 305-284-2580 (Fax),
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Abstract
STUDY DESIGN Investigation of the effects of the impairment of different nutritional pathways on the intervertebral disc degeneration patterns in terms of spatial distributions of cell density, glycosaminoglycan content, and water content. OBJECTIVE The aim of this study was to test the hypothesis that impairment of different nutritional pathways would result in different degenerative patterns in human discs. SUMMARY OF BACKGROUND DATA Impairment of nutritional pathways has been found to affect cell viability in the disc. However, details on how impairment of different nutritional pathways affects the disc degeneration patterns are unknown. METHODS A 3D finite element model was used for this study. This finite element method was based on the cell-activity coupled mechano-electrochemical theory for cartilaginous tissues. Impairment of the nutritional pathways was simulated by lowering the nutrition level at the disc boundaries. Effects of the impartment of cartilaginous endplate-nucleus pulposus (CEP-NP) pathway only (Case 1), annulus fibrosus (AF) pathway only (Case 2), and both pathways (Case 3) on disc degeneration patterns were studied. RESULTS The predicted critical levels of nutrition for Case 1, Case 2, and Case 3 were around 30%, 20%, and 50% of the reference values, respectively. Below this critical level, the disc degeneration would occur. Disc degeneration appeared mainly in the NP for Case 1, in the outer AF for Case 2, and in both the NP and inner to middle AF for Case 3. For Cases 1 and 3, the loss of water content was primarily located in the mid-axial plane, which is consistent with the horizontal gray band seen in some T2-weighted magnetic resonance imaging (MRI). For the disc geometry used in this study, it was predicted that there existed a high-intensity zone (for Case 3), as seen in some T2-weighted MRI images. CONCLUSION Impairment of different nutrition pathways results in different degenerative patterns. LEVEL OF EVIDENCE N/A.
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Sitte I, Klosterhuber M, Lindtner RA, Freund MC, Neururer SB, Pfaller K, Kathrein A. Morphological changes in the human cervical intervertebral disc post trauma: response to fracture-type and degeneration grade over time. 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 2015; 25:80-95. [PMID: 26188769 DOI: 10.1007/s00586-015-4089-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Revised: 06/20/2015] [Accepted: 06/26/2015] [Indexed: 12/25/2022]
Abstract
PURPOSE In the first 24 h post-intervertebral disc (IVD) trauma, up to 75 % cell death has been reported. In addition, burst fractures cause post-traumatic disc degeneration by elevated pro-apoptotic and pro-inflammatory gene transcription. Moreover, some patients have pre-trauma degenerative disc disease. The aim of the study was to assess histological changes and cell-death over a time period of up to 1 year caused by mechanical and structural factors. METHODS 116 anterior portions of IVDs of the cervical spine were studied histologically by light microscopy and ultrastructurally by transmission electron microscopy (TEM). The group was investigated with regard to three main parameters: fracture mechanism (compressive vs. tensile/shear loads), degeneration grade (low vs. high) and endplate fracture (with vs. without). Disc architecture (e.g. ruptures) was studied histologically. Cell morphology was examined ultrastructurally to quantify cell-death, healthy and balloon cells. According to ultrastructural observations, two time-groups (up to 6 days vs. later) were established. Statistical analyses were carried out within and between time-groups. RESULTS Histological changes were obvious in the annulus fibrosus where ruptures with haematoma were replaced by granulation tissue. Significant differences in cell-death were seen in the first few days due to different loads. In contrast to the more degenerated segments, low degenerated ones revealed significantly less cell death with time post-trauma. Interestingly, no difference was found between groups after the sixth day. Cell-death (mean 44 % for all investigated groups) remained high after day 6 post-trauma. CONCLUSION IVDs retrieved from low grade degenerated segments revealed a significant recovery, with less cell-death and a partially restored disc matrix, although cell-death remained high. Long-term clinical studies of stabilized segments arising from different fracture mechanisms are required.
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Affiliation(s)
- Ingrid Sitte
- Department of Traumatology, Medical University of Innsbruck, Anichstr. 35, 6020, Innsbruck, Austria.
| | - Miranda Klosterhuber
- Department of Traumatology, Medical University of Innsbruck, Anichstr. 35, 6020, Innsbruck, Austria
| | - Richard Andreas Lindtner
- Department of Traumatology, Medical University of Innsbruck, Anichstr. 35, 6020, Innsbruck, Austria
| | | | - Sabrina Barbara Neururer
- Department for Medical Statistics, Informatics and Health Economics, Medical University of Innsbruck, Innsbruck, Austria
| | - Kristian Pfaller
- Division of Histology and Embryology, Medical University of Innsbruck, Innsbruck, Austria
| | - Anton Kathrein
- Department of Traumatology and Sports Medicine, Sankt Vinzenz Krankenhaus Zams, Zams, Austria
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Belavy DL, Adams M, Brisby H, Cagnie B, Danneels L, Fairbank J, Hargens AR, Judex S, Scheuring RA, Sovelius R, Urban J, van Dieën JH, Wilke HJ. Disc herniations in astronauts: What causes them, and what does it tell us about herniation on earth? 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 2015; 25:144-154. [PMID: 25893331 DOI: 10.1007/s00586-015-3917-y] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Revised: 03/23/2015] [Accepted: 03/26/2015] [Indexed: 11/29/2022]
Abstract
PURPOSE Recent work showed an increased risk of cervical and lumbar intervertebral disc (IVD) herniations in astronauts. The European Space Agency asked the authors to advise on the underlying pathophysiology of this increased risk, to identify predisposing factors and possible interventions and to suggest research priorities. METHODS The authors performed a narrative literature review of the possible mechanisms, and conducted a survey within the team to prioritize research and prevention approaches. RESULTS AND CONCLUSIONS Based on literature review the most likely cause for lumbar IVD herniations was concluded to be swelling of the IVD in the unloaded condition during spaceflight. For the cervical IVDs, the knowledge base is too limited to postulate a likely mechanism or recommend approaches for prevention. Basic research on the impact of (un)loading on the cervical IVD and translational research is needed. The highest priority prevention approach for the lumbar spine was post-flight care avoiding activities involving spinal flexion, followed by passive spinal loading in spaceflight and exercises to reduce IVD hyper-hydration post-flight.
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Affiliation(s)
- Daniel L Belavy
- Center of Muscle and Bone Research, Charité University Medicine Berlin, Hindenburgdamm 30, 12203, Berlin, Germany. .,Centre for Physical Activity and Nutrition Research, School of Exercise and Nutrition Sciences, Deakin University, 221 Burwood Highway, Burwood, VIC, 3125, Australia.
| | - Michael Adams
- Centre for Comparative and Clinical Anatomy, University of Bristol, Southwell Street, Bristol, BS2 8EJ, UK
| | - Helena Brisby
- Department of Orthopedics, Institute of Clinical Sciences, Sahlgrenska Academy, Gothenburg University, Gothenborg, Sweden.,Department of Orthopedics, Sahlgrenska University Hospital, Gothenborg, Sweden
| | - Barbara Cagnie
- Department of Rehabiliation Sciences and Physiotherapy, Ghent University, De Pintelaan 185 3B3, 9000, Ghent, Belgium
| | - Lieven Danneels
- Department of Rehabiliation Sciences and Physiotherapy, Ghent University, De Pintelaan 185 3B3, 9000, Ghent, Belgium
| | - Jeremy Fairbank
- Nuffield Orthopaedic Centre, Headington, Oxford University Hospitals NHS Trust, Oxford, OX3 7HE, UK
| | - Alan R Hargens
- Department of Orthopaedic Surgery, University of California, San Diego, San Diego, CA, 92103-8894, USA
| | - Stefan Judex
- Bioengineering Building, Stony Brook University, Stony Brook, NY, 11794-5281, USA
| | | | - Roope Sovelius
- Centre for Military Medicine, Satakunta Air Command, PO.Box 1000, 33961, Pirkkala, Finland
| | - Jill Urban
- Department of Physiology, Anatomy and Genetics, Oxford University, Le Gros Clark Building, South Parks Road, Oxford, OX1 3QX, UK
| | - Jaap H van Dieën
- Faculty of Human Movement Sciences, MOVE Research Institute Amsterdam, VU University Amsterdam, van der Boechorststraat 9, Amsterdam, 1081 BT, The Netherlands
| | - Hans-Joachim Wilke
- Institute of Orthopaedic Research and Biomechanics, University of Ulm, Helmholtzstrasse 14, 89081, Ulm, Germany
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Abstract
STUDY DESIGN Simulate the progression of human disc degeneration. OBJECTIVE The objective of this study was to quantitatively analyze and simulate the changes in cell density, nutritional level, proteoglycan (PG) content, water content, and volume during human disc degeneration using a numerical method. SUMMARY OF BACKGROUND DATA Understanding the cause and progression of intervertebral disc degeneration is crucial for developing effective treatment strategies for intervertebral disc degeneration-related diseases. During tissue degeneration, the disc undergoes losses of cell viability and activities, changes in extracellular matrix composition and structure, and compromise of the tissue-level integrity and function, which is significantly influenced by the intercoupled biological, chemical, electrical, and mechanical signals in the disc. Characterizing these signals in human discs in vivo is difficult. METHODS A realistic 3-dimensional finite element model of the human intervertebral disc was developed on the basis of biomechanoelectrochemical continuum mixture theory. The theoretical framework and the constitutive relationships were all biophysics based. All the material properties were obtained from experimental results. The cell-mediated disc degeneration process caused by lowered nutritional levels at disc boundaries was simulated and validated by comparing with experimental results. RESULTS Cell density reached equilibrium state in 30 days after reduced nutritional supply at the disc boundary, whereas the PG and water contents reached a new equilibrium state in 55 years. The simulated results for the distributions of PG and water contents within the disc were consistent with the results measured in the literature, except for the distribution of PG content in the sagittal direction. CONCLUSION Poor nutritional supply has a long-term effect on disc degeneration.
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Zhu Q, Gao X, Gu W. Temporal changes of mechanical signals and extracellular composition in human intervertebral disc during degenerative progression. J Biomech 2014; 47:3734-43. [PMID: 25305690 DOI: 10.1016/j.jbiomech.2014.09.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Revised: 08/27/2014] [Accepted: 09/03/2014] [Indexed: 01/08/2023]
Abstract
In this study, a three-dimensional finite element model was used to investigate the changes in tissue composition and mechanical signals within human lumbar intervertebral disc during the degenerative progression. This model was developed based on the cell-activity coupled mechano-electrochemical mixture theory. The disc degeneration was simulated by lowering nutrition levels at disc boundaries, and the temporal and spatial distributions of the fixed charge density, water content, fluid pressure, Von Mises stress, and disc deformation were analyzed. Results showed that fixed charge density, fluid pressure, and water content decreased significantly in the nucleus pulposus (NP) and the inner to middle annulus fibrosus (AF) regions of the degenerative disc. It was found that, with degenerative progression, the Von Mises stress (relative to that at healthy state) increased within the disc, with a larger increase in the outer AF region. Both the disc volume and height decreased with the degenerative progression. The predicted results of fluid pressure change in the NP were consistent with experimental findings in the literature. The knowledge of the variations of temporal and spatial distributions of composition and mechanical signals within the human IVDs provide a better understanding of the progression of disc degeneration.
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Affiliation(s)
- Qiaoqiao Zhu
- Tissue Biomechanics Lab, Department of Biomedical Engineering, University of Miami, Coral Gables, FL, USA
| | - Xin Gao
- Department of Mechanical and Aerospace Engineering, University of Miami, P.O. Box 248294, Coral Gables, FL, 33124-0624, USA
| | - Weiyong Gu
- Tissue Biomechanics Lab, Department of Biomedical Engineering, University of Miami, Coral Gables, FL, USA; Department of Mechanical and Aerospace Engineering, University of Miami, P.O. Box 248294, Coral Gables, FL, 33124-0624, USA.
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Sitte I, Kathrein A, Klosterhuber M, Lindtner RA, Neururer SB, Rauch S, Kuhn V, Schmoelz W. Morphological similarities after compression trauma of bovine and human intervertebral discs: Do disc cells have a chance of surviving? J Orthop Res 2014; 32:1198-207. [PMID: 24888549 DOI: 10.1002/jor.22655] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Accepted: 01/21/2014] [Indexed: 02/04/2023]
Abstract
To study the behavior of bovine disc cells and changes in disc matrix following in vitro compression tests; to compare the findings to investigations on human intervertebral discs (IVD) after burst fracture of the cervical spine. Healthy IVDs (n = 21) from three bovine tails were studied at 6 and 12 h post-mortem, with 16 IVDs subjected to impact loading and five as unloaded controls. IVDs (n = 8) from patients with burst fractures were compared to the bovine compression group. Specimens were studied macroscopically, histologically, and ultrastructurally for healthy cells, balloon cells, and disc cell death (DCD). Annulus ruptures were seen in both post-trauma groups, with radial ruptures being present histologically in all loaded bovine discs. Balloon cells were found in some human IVDs and were induced in vitro in bovine loaded discs within a distinct range of absorbed energy. There was a positive correlation between DCD and absorbed energy in all compartments of bovine discs. Both species showed similar patterns of DCD in the different compartments. This study was able to show similarities between both species in cell morphologies and matrix damage. The survival of the disc after substantial compression trauma thus seems to remain highly questionable.
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Affiliation(s)
- Ingrid Sitte
- Department of Traumatology, Medical University of Innsbruck, Anichstr. 35, A-6020, Innsbruck, Austria
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Hegewald AA, Cluzel J, Krüger JP, Endres M, Kaps C, Thomé C. Effects of initial boost with TGF-beta 1 and grade of intervertebral disc degeneration on 3D culture of human annulus fibrosus cells. J Orthop Surg Res 2014; 9:73. [PMID: 25116605 PMCID: PMC4143571 DOI: 10.1186/s13018-014-0073-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2014] [Accepted: 07/25/2014] [Indexed: 12/01/2022] Open
Abstract
Background Three-dimensional (3D) culture in porous biomaterials as well as stimulation with growth factors are known to be supportive for intervertebral disc cell differentiation and tissue formation. Unless sophisticated releasing systems are used, however, effective concentrations of growth factors are maintained only for a very limited amount of time in in vivo applications. Therefore, we investigated, if an initial boost with transforming growth factor-beta 1 (TGF-beta 1) is capable to induce a lasting effect of superior cartilaginous differentiation in slightly and severely degenerated human annulus fibrosus (AF) cells. Methods Human AF tissue was harvested during surgical treatment of six adult patients with lumbar spinal diseases. Grading of disc degeneration was performed with magnet resonance imaging. AF cells were isolated and expanded in monolayer culture and rearranged three-dimensionally in a porous biomaterial consisting of stepwise absorbable poly-glycolic acid and poly-(lactic-co-glycolic) acid and a supportive fine net of non-absorbable polyvinylidene fluoride. An initial boost of TGF-beta 1 or TGF-beta 1 and hyaluronan was applied and compared with controls. Matrix formation was assessed at days 7 and 21 by (1) histological staining of the typical extracellular matrix molecules proteoglycan and type I and type II collagens and by (2) real-time gene expression analysis of aggrecan, decorin, biglycan, type I, II, III, and X collagens as well as of catabolic matrix metalloproteinases MMP-2 and MMP-13. Results An initial boost with TGF-beta 1 or TGF-beta 1 and hyaluronan did not enhance the expression of characteristic AF matrix molecules in our 3D culture system. AF cells showed high viability in the progressively degrading biomaterial. Stratification by grade of intervertebral disc degeneration showed that AF cells from both, slightly degenerated, or severely degenerated tissue are capable of significant up-regulations of characteristic matrix molecules in 3D culture. AF cells from severely degenerated tissue, however, displayed significantly lower up-regulations in some matrix molecules such as aggrecan. Conclusions We failed to show a supportive effect of an initial boost with TGF-beta 1 in our 3D culture system. This underlines the need for further investigations on growth factor releasing systems.
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Affiliation(s)
- Aldemar Andres Hegewald
- Department of Neurosurgery, University Medical Center Mannheim, Heidelberg University, Theodor-Kutzer-Ufer 1-3, Mannheim 68167, Germany.
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Sivan SS, Wachtel E, Roughley P. Structure, function, aging and turnover of aggrecan in the intervertebral disc. Biochim Biophys Acta Gen Subj 2014; 1840:3181-9. [PMID: 25065289 DOI: 10.1016/j.bbagen.2014.07.013] [Citation(s) in RCA: 117] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2014] [Revised: 07/11/2014] [Accepted: 07/18/2014] [Indexed: 11/17/2022]
Abstract
BACKGROUND Aggrecan is the major non-collagenous component of the intervertebral disc. It is a large proteoglycan possessing numerous glycosaminoglycan chains and the ability to form aggregates in association with hyaluronan. Its abundance and unique molecular features provide the disc with its osmotic properties and ability to withstand compressive loads. Degradation and loss of aggrecan result in impairment of disc function and the onset of degeneration. SCOPE OF REVIEW This review summarizes current knowledge concerning the structure and function of aggrecan in the normal intervertebral disc and how and why these change in aging and degenerative disc disease. It also outlines how supplementation with aggrecan or a biomimetic may be of therapeutic value in treating the degenerate disc. MAJOR CONCLUSIONS Aggrecan abundance reaches a plateau in the early twenties, declining thereafter due to proteolysis, mainly by matrix metalloproteinases and aggrecanases, though degradation of hyaluronan and non-enzymic glycation may also participate. Aggrecan loss is an early event in disc degeneration, although it is a lengthy process as degradation products may accumulate in the disc for decades. The low turnover rate of the remaining aggrecan is an additional contributing factor, preventing protein renewal. It may be possible to retard the degenerative process by restoring the aggrecan content of the disc, or by supplementing with a bioimimetic possessing similar osmotic properties. GENERAL SIGNIFICANCE This review provides a basis for scientists and clinicians to understand and appreciate the central role of aggrecan in the function, degeneration and repair of the intervertebral disc.
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Affiliation(s)
- Sarit Sara Sivan
- Department of Biotechnology Engineering, ORT Braude College, Karmiel 21982 Israel.
| | - Ellen Wachtel
- Faculty of Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Peter Roughley
- Shriners Hospital for Children, Genetics Unit, 1529 Cedar Avenue, Montreal, Quebec H3G 1A6, Canada
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Yang X, Jin L, Yao L, Shen FH, Shimer AL, Li X. Antioxidative nanofullerol prevents intervertebral disk degeneration. Int J Nanomedicine 2014; 9:2419-30. [PMID: 24876775 PMCID: PMC4035310 DOI: 10.2147/ijn.s60853] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Compelling evidence suggests that reactive oxygen species (ROS) play a pivotal role in disk degeneration. Fullerol nanoparticles prepared in aqueous solution have been demonstrated to have outstanding ability to scavenge ROS. In this report, in vitro and in vivo models were used to study the efficacy of fullerol in preventing disk degeneration. For in vitro experiments, a pro-oxidant H2O2 or an inflammatory cytokine interleukin (IL)-1β was employed to induce degenerated phenotypes in human nucleus pulposus cells encapsulated in alginate beads, and fullerol was added in the culture medium. For the animal study, an annulus-puncture model with rabbit was created, and fullerol was injected into disks. It was shown that cytotoxicity and cellular ROS level induced by H2O2 were significantly diminished by fullerol. IL-1β-induced nitric oxide generation in culture medium was suppressed by fullerol as well. Gene-profile and biochemical assays showed that fullerol effectively reversed the matrix degradation caused by either H2O2 or IL-1β. The animal study delineated that intradiskal injection of fullerol prevented disk degeneration, increasing water and proteoglycan content and inhibiting ectopic bone formation. These results suggest that antioxidative fullerol may have a potential therapeutic application for disk degeneration.
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Affiliation(s)
- Xinlin Yang
- Orthopaedic Research Laboratories, University of Virginia, Charlottesville, VA, USA
| | - Li Jin
- Orthopaedic Research Laboratories, University of Virginia, Charlottesville, VA, USA
| | - Lu Yao
- School of Life Science, Beijing Institute of Technology, Beijing, People's Republic of China ; Research Institute of Beijing Tongrentang Co., Ltd, Beijing, People's Republic of China
| | - Francis H Shen
- Orthopaedic Research Laboratories, University of Virginia, Charlottesville, VA, USA
| | - Adam L Shimer
- Orthopaedic Research Laboratories, University of Virginia, Charlottesville, VA, USA
| | - Xudong Li
- Orthopaedic Research Laboratories, University of Virginia, Charlottesville, VA, USA
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Adams MA, Lama P, Zehra U, Dolan P. Why do some intervertebral discs degenerate, when others (in the same spine) do not? Clin Anat 2014; 28:195-204. [PMID: 24753325 DOI: 10.1002/ca.22404] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Revised: 03/04/2014] [Accepted: 04/01/2014] [Indexed: 02/06/2023]
Abstract
This review suggests why some discs degenerate rather than age normally. Intervertebral discs are avascular pads of fibrocartilage that allow movement between vertebral bodies. Human discs have a low cell density and a limited ability to adapt to mechanical demands. With increasing age, the matrix becomes yellowed, fibrous, and brittle, but if disc structure remains intact, there is little impairment in function, and minimal ingrowth of blood vessels or nerves. Approximately half of old lumbar discs degenerate in the sense of becoming physically disrupted. The posterior annulus and lower lumbar discs are most affected, presumably because they are most heavily loaded. Age and genetic inheritance can weaken discs to such an extent that they are physically disrupted during everyday activities. Damage to the endplate or annulus typically decompresses the nucleus, concentrates stress within the annulus, and allows ingrowth of nerves and blood vessels. Matrix disruption progresses by mechanical and biological means. The site of initial damage leads to two disc degeneration "phenotypes": endplate-driven degeneration is common in the upper lumbar and thoracic spine, and annulus-driven degeneration is common at L4-S1. Discogenic back pain can be initiated by tissue disruption, and amplified by inflammation and infection. Healing is possible in the outer annulus only, where cell density is highest. We conclude that some discs degenerate because they are disrupted by excessive mechanical loading. This can occur without trauma if tissues are weakened by age and genetic inheritance. Moderate mechanical loading, in contrast, strengthens all spinal tissues, including discs.
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Affiliation(s)
- Michael A Adams
- Centre for Comparative and Clinical Anatomy, University of Bristol, United Kingdom
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Bains W. Transglutaminse 2 and EGGL, the protein cross-link formed by transglutaminse 2, as therapeutic targets for disabilities of old age. Rejuvenation Res 2013; 16:495-517. [PMID: 23968147 PMCID: PMC3869435 DOI: 10.1089/rej.2013.1452] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Accepted: 08/22/2013] [Indexed: 12/17/2022] Open
Abstract
Aging of the extracellular matrix (ECM), the protein matrix that surrounds and penetrates the tissues and binds the body together, contributes significantly to functional aging of tissues. ECM proteins become increasingly cross-linked with age, and this cross-linking is probably important in the decline of the ECM's function. This article reviews the role of ε-(γ-glutamyl)-lysine (EGGL), a cross-link formed by transglutaminase enzymes, and particularly the widely expressed isozyme transglutaminase 2 (TG2), in the aging ECM. There is little direct data on EGGL accumulation with age, and no direct evidence of a role of EGGL in the aging of the ECM with pathology. However, several lines of circumstantial evidence suggest that EGGL accumulates with age, and its association with pathology suggests that this might reflect degradation of ECM function. TG activity increases with age in many circumstances. ECM protein turnover is such that some EGGL made by TG is likely to remain in place for years, if not decades, in healthy tissue, and both EGGL and TG levels are enhanced by age-related diseases. If further research shows EGGL does accumulate with age, removing it could be of therapeutic benefit. Also reviewed is the blockade of TG and active removal of EGGL as therapeutic strategies, with the conclusion that both have promise. EGGL removal may have benefit for acute fibrotic diseases, such as tendinopathy, and for treating generalized decline in ECM function with old age. Extracellular TG2 and EGGL are therefore therapeutic targets both for specific and more generalized diseases of aging.
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Affiliation(s)
- William Bains
- SRF Laboratory, Department of Chemical Engineering and Biotechnology, University of Cambridge , Cambridge, United Kingdom
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Akhatib B, Önnerfjord P, Gawri R, Ouellet J, Jarzem P, Heinegård D, Mort J, Roughley P, Haglund L. Chondroadherin fragmentation mediated by the protease HTRA1 distinguishes human intervertebral disc degeneration from normal aging. J Biol Chem 2013; 288:19280-7. [PMID: 23673665 PMCID: PMC3696698 DOI: 10.1074/jbc.m112.443010] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2012] [Revised: 05/02/2013] [Indexed: 01/21/2023] Open
Abstract
Chondroadherin, a member of the leucine-rich repeat family, has previously been demonstrated to be fragmented in some juveniles with idiopathic scoliosis. This observation led us to investigate adults with disc degeneration. Immunoblotting analysis demonstrated that non-degenerate discs from three different age groups show no chondroadherin fragmentation. Furthermore, the chondroadherin fragments in adult degenerate disc and the juvenile scoliotic disc were compared via immunoblot analysis and appeared to have a similar size. We then investigated whether or not chondroadherin fragmentation increases with the severity of disc degeneration. Three different samples with different severities were chosen from the same disc, and chondroadherin fragmentation was found to be more abundant with increasing severity of degeneration. This observation led us to the creation of a neoepitope antibody to the cleavage site observed. We then observed that the cleavage site in adult degenerate discs and juvenile scoliotic discs was identical as confirmed by the neoepitope antibody. Consequently, investigation of the protease capable of cleaving chondroadherin at this site was necessary. In vitro digests of disc tissue demonstrated that ADAMTS-4 and -5; cathepsins K, B, and L; and MMP-3, -7, -12, and -13 were incapable of cleavage of chondroadherin at this site and that HTRA1 was indeed the only protease capable. Furthermore, increased protein levels of the processed form of HTRA1 were demonstrated in degenerate disc tissues via immunoblotting. The results suggest that chondroadherin fragmentation can be used as a biomarker to distinguish the processes of disc degeneration from normal aging.
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Affiliation(s)
- Bashar Akhatib
- From the Orthopaedic Research Laboratory, McGill University, Montreal, Quebec H3G 1A4, Canada
| | - Patrik Önnerfjord
- Department of Clinical Sciences, Lund Section for Rheumatology, Molecular Skeletal Biology, Biomedical Center C12, Lund University, SE-22184 Lund, Sweden
| | - Rahul Gawri
- From the Orthopaedic Research Laboratory, McGill University, Montreal, Quebec H3G 1A4, Canada
| | - Jean Ouellet
- Department of Clinical Sciences, Lund Section for Rheumatology, Molecular Skeletal Biology, Biomedical Center C12, Lund University, SE-22184 Lund, Sweden
- McGill Scoliosis and Spine Group, Montreal, Quebec H3A 1A1, Canada, and
| | - Peter Jarzem
- Department of Clinical Sciences, Lund Section for Rheumatology, Molecular Skeletal Biology, Biomedical Center C12, Lund University, SE-22184 Lund, Sweden
- McGill Scoliosis and Spine Group, Montreal, Quebec H3A 1A1, Canada, and
| | - Dick Heinegård
- Department of Clinical Sciences, Lund Section for Rheumatology, Molecular Skeletal Biology, Biomedical Center C12, Lund University, SE-22184 Lund, Sweden
| | - John Mort
- Genetics Unit, Shriners Hospitals for Children, Montreal, Quebec H3G 1A6, Canada
| | - Peter Roughley
- Genetics Unit, Shriners Hospitals for Children, Montreal, Quebec H3G 1A6, Canada
| | - Lisbet Haglund
- From the Orthopaedic Research Laboratory, McGill University, Montreal, Quebec H3G 1A4, Canada
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Sivan SS, Hayes AJ, Wachtel E, Caterson B, Merkher Y, Maroudas A, Brown S, Roberts S. Biochemical composition and turnover of the extracellular matrix of the normal and degenerate 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 2013; 23 Suppl 3:S344-53. [DOI: 10.1007/s00586-013-2767-8] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2012] [Revised: 03/01/2013] [Accepted: 03/30/2013] [Indexed: 12/21/2022]
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Tran CM, Shapiro IM, Risbud MV. Molecular regulation of CCN2 in the intervertebral disc: lessons learned from other connective tissues. Matrix Biol 2013; 32:298-306. [PMID: 23567513 DOI: 10.1016/j.matbio.2013.03.006] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2013] [Revised: 03/28/2013] [Accepted: 03/29/2013] [Indexed: 01/07/2023]
Abstract
Connective tissue growth factor (CCN2/CTGF) plays an important role in extracellular matrix synthesis, especially in skeletal tissues such as cartilage, bone, and the intervertebral disc. As a result there is a growing interest in examining the function and regulation of this important molecule in the disc. This review discusses the regulation of CCN2 by TGF-β and hypoxia, two critical determinants that characterize the disc microenvironment, and discusses known functions of CCN2 in the disc. The almost ubiquitous regulation of CCN2 by TGF-β, including that seen in the disc, emphasizes the importance of the TGF-β-CCN2 relationship, especially in terms of extracellular matrix synthesis. Likewise, the unique cross-talk between CCN2 and HIF-1 in the disc highlights the tissue and niche specific mode of regulation. Taken together the current literature supports an anabolic role for CCN2 in the disc and its involvement in the maintenance of tissue homeostasis during both health and disease. Further studies of CCN2 in this tissue may reveal valuable targets for the biological therapy of disc degeneration.
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Affiliation(s)
- Cassie M Tran
- Department of Orthopaedic Surgery and Graduate Program in Cell and Developmental Biology, Thomas Jefferson University, Philadelphia, USA
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Tran CM, Fujita N, Huang BL, Ong JR, Lyons KM, Shapiro IM, Risbud MV. Hypoxia-inducible factor (HIF)-1α and CCN2 form a regulatory circuit in hypoxic nucleus pulposus cells: CCN2 suppresses HIF-1α level and transcriptional activity. J Biol Chem 2013; 288:12654-66. [PMID: 23530034 DOI: 10.1074/jbc.m112.448860] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The objective of the study was to investigate if hypoxia-inducible factor (HIF)-1α and connective tissue growth factor (CCN2) form a regulatory network in hypoxic nucleus pulposus (NP) cells. A decrease in CCN2 expression and proximal promoter activity was observed in NP cells after hypoxic culture. Analysis of both human and mouse CCN2 promoters using the JASPAR core database revealed the presence of putative hypoxia response elements. Transfection experiments showed that both promoter activities and CCN2 expression decreases in hypoxia in a HIF-1α-dependent fashion. Interestingly, deletion analysis and mutation of the hypoxia responsive elements individually or in combination resulted in no change in promoter activity in response to hypoxia or in response to HIF-1α, suggesting an indirect mode of regulation. Notably, silencing of endogenous CCN2 increased HIF-1α levels and its target gene expression, suggesting a role for CCN2 in controlling basal HIF-1α levels. On the other hand, treatment of cells with rCCN2 resulted in a decrease in the ability of HIF-1α transactivating domain to recruit co-activators and diminished target gene expression. Last, knockdown of CCN2 in NP cells results in a significant decrease in GAG synthesis and expression of AGGRECAN and COLLAGEN II. Immunohistochemical staining of intervertebral discs of Ccn2 null embryos shows a decrease in aggrecan. These findings reveal a negative feedback loop between CCN2 and HIF-1α in NP cells and demonstrate a role for CCN2 in maintaining matrix homeostasis in this tissue.
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Affiliation(s)
- Cassie M Tran
- Department of Orthopaedic Surgery and Graduate Program in Cell and Developmental Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA
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The Role of HA and Has2 in the Development and Function of the Skeleton. EXTRACELLULAR MATRIX IN DEVELOPMENT 2013. [DOI: 10.1007/978-3-642-35935-4_9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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Towards biological anulus repair: TGF-β3, FGF-2 and human serum support matrix formation by human anulus fibrosus cells. Tissue Cell 2012; 45:68-76. [PMID: 23122986 DOI: 10.1016/j.tice.2012.09.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2012] [Revised: 09/13/2012] [Accepted: 09/23/2012] [Indexed: 01/04/2023]
Abstract
Closure and biological repair of anulus fibrosus (AF) defects in intervertebral disc diseases is a therapeutic challenge. The aim of our study was to evaluate the anabolic properties of bioactive factors on cartilaginous matrix formation by AF cells. Human AF cells were harvested from degenerated lumbar AF tissue and expanded in monolayer culture. AF cell differentiation and matrix formation was initiated by forming pellet cultures and stimulation with hyaluronic acid (HA), human serum (HS), fibroblast growth factor-2 (FGF-2), transforming growth factor-β3 (TGF-β3) and TGF-β3/FGF-2 for up to 4 weeks. Matrix formation was assessed histologically by staining of proteoglycan, type I and type II collagens and by gene expression analysis of typical extracellular matrix molecules and of catabolic matrix metalloproteinases MMP-2 and MMP-13. AF cells, stimulated with HS, FGF-2 and most pronounced with TGF-β3 or TGF-β3/FGF-2 formed a cartilaginous matrix with significantly enhanced expression of matrix molecules and of MMP-13. Stimulation of AF cells with TGF-β3 was accompanied by induction of type X collagen, known to occur in hypertrophic cartilage cells having mineralizing potential. HA did not show any chondro-inductive characteristics. These findings suggest human serum, FGF-2 and TGF-β3 as possible candidates to support biological treatment strategies of AF defects.
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Annulus fissures are mechanically and chemically conducive to the ingrowth of nerves and blood vessels. Spine (Phila Pa 1976) 2012; 37:1883-91. [PMID: 22706090 DOI: 10.1097/brs.0b013e318263ba59] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN Mechanical and biochemical analyses of cadaveric and surgically removed discs. OBJECTIVE To test the hypothesis that fissures in the annulus of degenerated human discs are mechanically and chemically conducive to the ingrowth of nerves and blood vessels. SUMMARY OF BACKGROUND DATA Discogenic back pain is closely associated with fissures in the annulus fibrosus, and with the ingrowth of nerves and blood vessels. METHODS Three complementary studies were performed. First, 15 cadaveric discs that contained a major annulus fissure were subjected to 1 kN compression, while a miniature pressure transducer was pulled through the disc to obtain distributions of matrix compressive stress perpendicular to the fissure axis. Second, Safranin O staining was used to evaluate focal loss of proteoglycans from within annulus fissures in 25 surgically removed disc samples. Third, in 21 cadaveric discs, proteoglycans (sulfated glycosaminoglycans [sGAGs]) and water concentration were measured biochemically in disrupted regions of annulus containing 1 or more fissures, and in adjacent intact regions. RESULTS Reductions in compressive stress within annulus fissures averaged 36% to 46%, and could have been greater at the fissure axis. Stress reductions were greater in degenerated discs, and were inversely related to nucleus pressure (R(2) = 47%; P = 0.005). Safranin O stain intensity indicated that proteoglycan concentration was typically reduced by 40% at a distance of 600 μm from the fissure axis, and the width of the proteoglycan-depleted zone increased with age (P < 0.006; R(2) = 0.29) and with general proteoglycan loss (P < 0.001; R(2) = 0.32). Disrupted regions of annulus contained 36% to 54% less proteoglycans than adjacent intact regions from the same discs, although water content was reduced only slightly. CONCLUSION Annulus fissures provide a low-pressure microenvironment that allows focal proteoglycan loss, leaving a matrix that is conducive to nerve and blood vessel ingrowth.
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