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Dewle A, Rakshasmare P, Srivastava A. A Polycaprolactone (PCL)-Supported Electrocompacted Aligned Collagen Type-I Patch for Annulus Fibrosus Repair and Regeneration. ACS APPLIED BIO MATERIALS 2021; 4:1238-1251. [DOI: 10.1021/acsabm.0c01084] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ankush Dewle
- Department of Medical Devices, National Institute of Pharmaceutical Education and Research-Ahmedabad (NIPER-A), Opp. Airforce
Station, Palaj, Gandhinagar 382355, Gujarat, India
| | - Prakash Rakshasmare
- Department of Medical Devices, National Institute of Pharmaceutical Education and Research-Ahmedabad (NIPER-A), Opp. Airforce
Station, Palaj, Gandhinagar 382355, Gujarat, India
| | - Akshay Srivastava
- Department of Medical Devices, National Institute of Pharmaceutical Education and Research-Ahmedabad (NIPER-A), Opp. Airforce
Station, Palaj, Gandhinagar 382355, Gujarat, India
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Advanced Strategies for the Regeneration of Lumbar Disc Annulus Fibrosus. Int J Mol Sci 2020; 21:ijms21144889. [PMID: 32664453 PMCID: PMC7402314 DOI: 10.3390/ijms21144889] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 07/02/2020] [Accepted: 07/08/2020] [Indexed: 12/15/2022] Open
Abstract
Damage to the annulus fibrosus (AF), the outer region of the intervertebral disc (IVD), results in an undesirable condition that may accelerate IVD degeneration causing low back pain. Despite intense research interest, attempts to regenerate the IVD have failed so far and no effective strategy has translated into a successful clinical outcome. Of particular significance, the failure of strategies to repair the AF has been a major drawback in the regeneration of IVD and nucleus replacement. It is unlikely to secure regenerative mediators (cells, genes, and biomolecules) and artificial nucleus materials after injection with an unsealed AF, as IVD is exposed to significant load and large deformation during daily activities. The AF defects strongly change the mechanical properties of the IVD and activate catabolic routes that are responsible for accelerating IVD degeneration. Therefore, there is a strong need to develop effective therapeutic strategies to prevent or reconstruct AF damage to support operational IVD regenerative strategies and nucleus replacement. By the way of this review, repair and regenerative strategies for AF reconstruction, their current status, challenges ahead, and future outlooks were discussed.
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van Uden S, Silva-Correia J, Oliveira JM, Reis RL. Current strategies for treatment of intervertebral disc degeneration: substitution and regeneration possibilities. Biomater Res 2017; 21:22. [PMID: 29085662 PMCID: PMC5651638 DOI: 10.1186/s40824-017-0106-6] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Accepted: 10/05/2017] [Indexed: 02/06/2023] Open
Abstract
Background Intervertebral disc degeneration has an annual worldwide socioeconomic impact masked as low back pain of over 70 billion euros. This disease has a high prevalence over the working age class, which raises the socioeconomic impact over the years. Acute physical trauma or prolonged intervertebral disc mistreatment triggers a biochemical negative tendency of catabolic-anabolic balance that progress to a chronic degeneration disease. Current biomedical treatments are not only ineffective in the long-run, but can also cause degeneration to spread to adjacent intervertebral discs. Regenerative strategies are desperately needed in the clinics, such as: minimal invasive nucleus pulposus or annulus fibrosus treatments, total disc replacement, and cartilaginous endplates decalcification. Main body Herein, it is reviewed the state-of-the-art of intervertebral disc regeneration strategies from the perspective of cells, scaffolds, or constructs, including both popular and unique tissue engineering approaches. The premises for cell type and origin selection or even absence of cells is being explored. Choice of several raw materials and scaffold fabrication methods are evaluated. Extensive studies have been developed for fully regeneration of the annulus fibrosus and nucleus pulposus, together or separately, with a long set of different rationales already reported. Recent works show promising biomaterials and processing methods applied to intervertebral disc substitutive or regenerative strategies. Facing the abundance of studies presented in the literature aiming intervertebral disc regeneration it is interesting to observe how cartilaginous endplates have been extensively neglected, being this a major source of nutrients and water supply for the whole disc. Conclusion Several innovative avenues for tackling intervertebral disc degeneration are being reported – from acellular to cellular approaches, but the cartilaginous endplates regeneration strategies remain unaddressed. Interestingly, patient-specific approaches show great promise in respecting patient anatomy and thus allow quicker translation to the clinics in the near future.
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Affiliation(s)
- Sebastião van Uden
- 3B's Research Group-Biomaterials, Biodegradables and Biomimetics, University of Minho, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, AvePark, Parque de Ciência e Tecnologia, Zona Industrial da Gandra, 4805-017 Barco GMR Gandra, Portugal.,ICVS/3B's-PT Government Associate Laboratory, Guimarães, Braga Portugal.,Present Address: Bioengineering Laboratories Srl, Viale Brianza 8, Meda, Italy.,Present Address: Politecnico di Milano, Piazza Leonardo da Vinci, 32 Milan, Italy
| | - Joana Silva-Correia
- 3B's Research Group-Biomaterials, Biodegradables and Biomimetics, University of Minho, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, AvePark, Parque de Ciência e Tecnologia, Zona Industrial da Gandra, 4805-017 Barco GMR Gandra, Portugal.,ICVS/3B's-PT Government Associate Laboratory, Guimarães, Braga Portugal
| | - Joaquim Miguel Oliveira
- 3B's Research Group-Biomaterials, Biodegradables and Biomimetics, University of Minho, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, AvePark, Parque de Ciência e Tecnologia, Zona Industrial da Gandra, 4805-017 Barco GMR Gandra, Portugal.,ICVS/3B's-PT Government Associate Laboratory, Guimarães, Braga Portugal.,The Discoveries Centre for Regenerative and Precision Medicine, Headquarters at University of Minho, Avepark, 4805-017 Barco Guimarães, Portugal
| | - Rui Luís Reis
- 3B's Research Group-Biomaterials, Biodegradables and Biomimetics, University of Minho, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, AvePark, Parque de Ciência e Tecnologia, Zona Industrial da Gandra, 4805-017 Barco GMR Gandra, Portugal.,ICVS/3B's-PT Government Associate Laboratory, Guimarães, Braga Portugal.,The Discoveries Centre for Regenerative and Precision Medicine, Headquarters at University of Minho, Avepark, 4805-017 Barco Guimarães, Portugal
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Tavakoli J. Tissue Engineering of the Intervertebral Disc's Annulus Fibrosus: A Scaffold-Based Review Study. Tissue Eng Regen Med 2017; 14:81-91. [PMID: 30603465 PMCID: PMC6171584 DOI: 10.1007/s13770-017-0024-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Revised: 04/10/2016] [Accepted: 06/08/2016] [Indexed: 12/11/2022] Open
Abstract
Tissue engineering as a high technology solution for treating disc's problem has been the focus of some researches recently; however, the upcoming successful results in this area depends on understanding the complexities of biology and engineering interface. Whereas the major responsibility of the nucleus pulposus is to provide a sustainable hydrated environment within the disc, the function of the annulus fibrosus (AF) is more mechanical, facilitating joint mobility and preventing radial bulging by confining of the central part, which makes the AF reconstruction important. Although the body of knowledge regarding the AF tissue engineering has grown rapidly, the opportunities to improve current understanding of how artificial scaffolds are able to mimic the AF concentric structure-including inter-lamellar matrix and cross-bridges-addressed unresolved research questions. The aim of this literature review was to collect and discuss, from the international scientific literature, information about tissue engineering of the AF based on scaffold fabrication and material properties, useful for developing new strategies in disc tissue engineering. The key parameter of this research was understanding if role of cross-bridges and inter-lamellar matrix has been considered on tissue engineering of the AF.
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Affiliation(s)
- Javad Tavakoli
- Medical Device Research Institute, School of Computer Science, Engineering and Mathematics, Flinders University, Adelaide, SA 5042 Australia
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5
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Oner T, Cengiz IF, Pitikakis M, Cesario L, Parascandolo P, Vosilla L, Viano G, Oliveira JM, Reis RL, Silva-Correia J. 3D segmentation of intervertebral discs: from concept to the fabrication of patient-specific scaffolds. ACTA ACUST UNITED AC 2017. [DOI: 10.2217/3dp-2016-0011] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Aim: To develop a methodology for producing patient-specific scaffolds that mimic the annulus fibrosus (AF) of the human intervertebral disc by means of combining MRI and 3D bioprinting. Methods: In order to obtain the AF 3D model from patient's volumetric MRI dataset, the RheumaSCORE segmentation software was used. Polycaprolactone scaffolds with three different internal architectures were fabricated by 3D bioprinting, and characterized by microcomputed tomography. Results: The demonstrated methodology of a geometry reconstruction pipeline enabled us to successfully obtain an accurate AF model and 3D print patient-specific scaffolds with different internal architectures. Conclusion: The results guide us toward patient-specific intervertebral disc tissue engineering as demonstrated by a way of manufacturing personalized scaffolds using patient's MRI data.
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Affiliation(s)
- T Oner
- 3B's Research Group – Biomaterials, Biodegradables and Biomimetics, University of Minho, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, Avepark – Parque de Ciência e Tecnologia, Zona Industrial da Gandra, 4805–017 Barco GMR, Portugal
- ICVS/3B's – PT Government Associated Laboratory, Braga, Portugal
| | - IF Cengiz
- 3B's Research Group – Biomaterials, Biodegradables and Biomimetics, University of Minho, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, Avepark – Parque de Ciência e Tecnologia, Zona Industrial da Gandra, 4805–017 Barco GMR, Portugal
- ICVS/3B's – PT Government Associated Laboratory, Braga, Portugal
| | | | | | | | | | - G Viano
- Softeco Sismat Srl, Genova, Italy
| | - JM Oliveira
- 3B's Research Group – Biomaterials, Biodegradables and Biomimetics, University of Minho, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, Avepark – Parque de Ciência e Tecnologia, Zona Industrial da Gandra, 4805–017 Barco GMR, Portugal
- ICVS/3B's – PT Government Associated Laboratory, Braga, Portugal
| | - RL Reis
- 3B's Research Group – Biomaterials, Biodegradables and Biomimetics, University of Minho, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, Avepark – Parque de Ciência e Tecnologia, Zona Industrial da Gandra, 4805–017 Barco GMR, Portugal
- ICVS/3B's – PT Government Associated Laboratory, Braga, Portugal
| | - J Silva-Correia
- 3B's Research Group – Biomaterials, Biodegradables and Biomimetics, University of Minho, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, Avepark – Parque de Ciência e Tecnologia, Zona Industrial da Gandra, 4805–017 Barco GMR, Portugal
- ICVS/3B's – PT Government Associated Laboratory, Braga, Portugal
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6
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Xu B, Xu H, Wu Y, Li X, Zhang Y, Ma X, Yang Q. Intervertebral Disc Tissue Engineering with Natural Extracellular Matrix-Derived Biphasic Composite Scaffolds. PLoS One 2015; 10:e0124774. [PMID: 25894203 PMCID: PMC4404358 DOI: 10.1371/journal.pone.0124774] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Accepted: 03/06/2015] [Indexed: 01/08/2023] Open
Abstract
Tissue engineering has provided an alternative therapeutic possibility for degenerative disc diseases. However, we lack an ideal scaffold for IVD tissue engineering. The goal of this study is to fabricate a novel biomimetic biphasic scaffold for IVD tissue engineering and evaluate the feasibility of developing tissue-engineered IVD in vitro and in vivo. In present study we developed a novel integrated biphasic IVD scaffold using a simple freeze-drying and cross-linking technique of pig bone matrix gelatin (BMG) for the outer annulus fibrosus (AF) phase and pig acellular cartilage ECM (ACECM) for the inner nucleus pulposus (NP) phase. Histology and SEM results indicated no residual cells remaining in the scaffold that featured an interconnected porous microstructure (pore size of AF and NP phase 401.4 ± 13.1 μm and 231.6 ± 57.2 μm, respectively). PKH26-labeled AF and NP cells were seeded into the scaffold and cultured in vitro. SEM confirmed that seeded cells could anchor onto the scaffold. Live/dead staining showed that live cells (green fluorescence) were distributed in the scaffold, with no dead cells (red fluorescence) being found. The cell-scaffold constructs were implanted subcutaneously into nude mice and cultured for 6 weeks in vivo. IVD-like tissue formed in nude mice as confirmed by histology. Cells in hybrid constructs originated from PKH26-labeled cells, as confirmed by in vivo fluorescence imaging system. In conclusion, the study demonstrates the feasibility of developing a tissue-engineered IVD in vivo with a BMG- and ACECM-derived integrated AF-NP biphasic scaffold. As well, PKH26 fluorescent labeling with in vivo fluorescent imaging can be used to track cells and analyse cell--scaffold constructs in vivo.
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Affiliation(s)
- Baoshan Xu
- Department of minimally invasive spine surgery, Tianjin Hospital, 406 Jie Fang Nan Road, Hexi District, Tianjin, 300211, People’s Republic of China
| | - Haiwei Xu
- Department of minimally invasive spine surgery, Tianjin Hospital, 406 Jie Fang Nan Road, Hexi District, Tianjin, 300211, People’s Republic of China
- Tianjin medical university, Tianjin, 300070, People’s Republic of China
| | - Yaohong Wu
- Department of minimally invasive spine surgery, Tianjin Hospital, 406 Jie Fang Nan Road, Hexi District, Tianjin, 300211, People’s Republic of China
- Tianjin medical university, Tianjin, 300070, People’s Republic of China
| | - Xiulan Li
- Cell Engineering Laboratory of Orthopaedic Institute, Tianjin Hospital, Tianjin, 300211, People’s Republic of China
| | - Yang Zhang
- Cell Engineering Laboratory of Orthopaedic Institute, Tianjin Hospital, Tianjin, 300211, People’s Republic of China
| | - Xinlong Ma
- Department of minimally invasive spine surgery, Tianjin Hospital, 406 Jie Fang Nan Road, Hexi District, Tianjin, 300211, People’s Republic of China
- * E-mail: (QY); (XM)
| | - Qiang Yang
- Department of minimally invasive spine surgery, Tianjin Hospital, 406 Jie Fang Nan Road, Hexi District, Tianjin, 300211, People’s Republic of China
- Tianjin medical university, Tianjin, 300070, People’s Republic of China
- * E-mail: (QY); (XM)
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7
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Oehme D, Goldschlager T, Rosenfeld JV, Ghosh P, Jenkin G. The role of stem cell therapies in degenerative lumbar spine disease: a review. Neurosurg Rev 2015; 38:429-45. [PMID: 25749802 DOI: 10.1007/s10143-015-0621-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Revised: 06/23/2014] [Accepted: 01/18/2015] [Indexed: 02/06/2023]
Abstract
Degenerative conditions of the lumbar spine are extremely common. Ninety percent of people over the age of 60 years have degenerative change on imaging; however, only a small minority of people will require spine surgery (Hicks et al. Spine (Phila Pa 1976) 34(12):1301-1306, 2009). This minority, however, constitutes a core element of spinal surgery practice. Whilst the patient outcomes from spinal surgeries have improved in recent years, some patients will remain with pain and disability despite technically successful surgery. Advances in regenerative medicine and stem cell therapies, particularly the use of mesenchymal stem cells and allogeneic mesenchymal precursor cells, have led to numerous clinical trials utilising these cell-based therapies to treat degenerative spinal conditions. Through cartilage formation and disc regeneration, fusion enhancement or via modification of pain pathways, stem cells are well suited to enhance spinal surgery practice. This review will focus on the outcomes of lumbar spinal procedures and the role of stem cells in the treatment of degenerative lumbar conditions to enhance clinical practice. The current status of clinical trials utilising stem cell therapies will be discussed, providing clinicians with an overview of the various cell-based treatments likely to be available to patients in the near future.
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Affiliation(s)
- David Oehme
- The Ritchie Centre, MIM-PHI Institute of Medical Research, Monash University Clayton Victoria, PO Box 6178, Clayton, VIC, 3141, Australia,
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8
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van Uden S, Silva-Correia J, Correlo VM, Oliveira JM, Reis RL. Custom-tailored tissue engineered polycaprolactone scaffolds for total disc replacement. Biofabrication 2015; 7:015008. [DOI: 10.1088/1758-5090/7/1/015008] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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9
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Guillaume O, Naqvi SM, Lennon K, Buckley CT. Enhancing cell migration in shape-memory alginate–collagen composite scaffolds: In vitro and ex vivo assessment for intervertebral disc repair. J Biomater Appl 2014; 29:1230-46. [DOI: 10.1177/0885328214557905] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Lower lumbar disc disorders pose a significant problem in an aging society with substantial socioeconomic consequences. Both inner tissue (nucleus pulposus) and outer tissue (annulus fibrosus) of the intervertebral disc are affected by such debilitating disorders and can lead to disc herniation and lower back pain. In this study, we developed an alginate–collagen composite porous scaffold with shape-memory properties to fill defects occurring in annulus fibrosus tissue of degenerated intervertebral discs, which has the potential to be administered using minimal invasive surgery. In the first part of this work, we assessed how collagen incorporation on preformed alginate scaffolds influences the physical properties of the final composite scaffold. We also evaluated the ability of annulus fibrosus cells to attach, migrate, and proliferate on the composite alginate–collagen scaffolds compared to control scaffolds (alginate only). In vitro experiments, performed in intervertebral disc-like microenvironmental conditions (low glucose and low oxygen concentrations), revealed that for alginate only scaffolds, annulus fibrosus cells agglomerated in clusters with limited infiltration and migration capacity. In comparison, for alginate–collagen scaffolds, annulus fibrosus cells readily attached and colonized constructs, while preserving their typical fibroblastic-like cell morphology with spreading behavior and intense cytoskeleton expression. In a second part of this study, we investigated the effects of alginate–collagen scaffold when seeded with bone marrow derived mesenchymal stem cells. In vitro, we observed that alginate–collagen porous scaffolds supported cell proliferation and extracellular matrix deposition (collagen type I), with secretion amplified by the local release of transforming growth factor-β3. In addition, when cultured in ex vivo organ defect model, alginate–collagen scaffolds maintained viability of transplanted mesenchymal stem cells for up to 5 weeks. Taken together, these findings illustrate the advantages of incorporating collagen as a means to enhance cell migration and proliferation in porous scaffolds which could be used to augment tissue repair strategies.
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Affiliation(s)
- Olivier Guillaume
- Trinity Centre for Bioengineering, Trinity Biomedical Sciences Institute, Trinity College Dublin, Ireland
- Department of Mechanical Engineering, School of Engineering, Trinity College Dublin, Ireland
| | - Syeda Masooma Naqvi
- Trinity Centre for Bioengineering, Trinity Biomedical Sciences Institute, Trinity College Dublin, Ireland
- Department of Mechanical Engineering, School of Engineering, Trinity College Dublin, Ireland
| | - Kerri Lennon
- Trinity Centre for Bioengineering, Trinity Biomedical Sciences Institute, Trinity College Dublin, Ireland
- Department of Mechanical Engineering, School of Engineering, Trinity College Dublin, Ireland
| | - Conor Timothy Buckley
- Trinity Centre for Bioengineering, Trinity Biomedical Sciences Institute, Trinity College Dublin, Ireland
- Department of Mechanical Engineering, School of Engineering, Trinity College Dublin, Ireland
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10
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Shape-memory porous alginate scaffolds for regeneration of the annulus fibrosus: effect of TGF-β3 supplementation and oxygen culture conditions. Acta Biomater 2014; 10:1985-95. [PMID: 24380722 DOI: 10.1016/j.actbio.2013.12.037] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Revised: 12/16/2013] [Accepted: 12/19/2013] [Indexed: 12/28/2022]
Abstract
Disc herniation as a result of degenerative or traumatic injury is believed to be the primary instigator of low back pain. At present there is a lack of viable treatment options to repair damaged annulus fibrosus (AF) tissue. Developing alternative strategies to fill and repair ruptured AF tissue is a key challenge. In this work we developed a porous alginate scaffold with shape-memory properties which can be delivered using minimally invasive approaches and recover its original geometry once hydrated. Covalently cross-linked alginate hydrogels were created using carbodiimide chemistry, followed by a freeze-drying step to impart porosity and create porous scaffolds. Results showed that porous alginate scaffolds exhibited shape-memory recovery and mechanical behaviour that could be modulated depending on the cross-linker concentrations. The scaffold can be repeatedly compressed and expanded, which provides the potential to deliver the biomaterial directly to the damaged area of the AF tissue. In vitro experiments demonstrated that scaffolds were cytocompatible and supported cell seeding, penetration and proliferation under intervertebral-disc-like microenvironmental conditions (low glucose media and low oxygen concentration). Extracellular matrix (ECM) was secreted by AF cells with TGF-β3 stimulation and after 21days had filled the porous scaffold network. This biological matrix was rich in sulfated glycosaminoglycan and collagen type I, which are the main compounds of native AF tissue. Successful ECM deposition was also confirmed by the increase in the peak stress of the scaffold. However, the immaturity of the matrix network after only 21days of in vitro culture was not sufficient to attain native AF tissue mechanical properties. The ability to deliver porous scaffolds using minimal invasive approaches that can potentially promote the regeneration of AF defects provides an exciting new avenue for disc repair.
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11
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Sharifi S, Bulstra SK, Grijpma DW, Kuijer R. Treatment of the degenerated intervertebral disc; closure, repair and regeneration of the annulus fibrosus. J Tissue Eng Regen Med 2014; 9:1120-32. [PMID: 24616324 DOI: 10.1002/term.1866] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2013] [Revised: 09/19/2013] [Accepted: 11/25/2013] [Indexed: 12/25/2022]
Abstract
Degeneration of the intervertebral disc (IVD) and disc herniation are two causes of low back pain. The aetiology of these disorders is unknown, but tissue weakening, which primarily occurs due to inherited genetic factors, ageing, nutritional compromise and loading history, is the basic factor causing disc degeneration. Symptomatic disc herniation mainly causes radicular pain. Current treatments of intervertebral disc degeneration and low back pain are based on alleviating the symptoms and comprise administration of painkillers or surgical methods such as spinal fusion. None of these methods is completely successful. Current research focuses on regeneration of the IVD and particularly on regeneration of the nucleus pulposus. Less attention has been directed to the repair or regeneration of the annulus fibrosus, although this is the key to successful nucleus pulposus, and therewith IVD, repair. This review focuses on the importance of restoring the function of the annulus fibrosus, as well as on the repair, replacement or regeneration of the annulus fibrosus in combination with restoration of the function of the nucleus pulposus, to treat low back pain.
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Affiliation(s)
- Shahriar Sharifi
- University of Groningen, University Medical Center Groningen, W. J. Kolff Institute, Department of Biomedical Engineering, Groningen, The Netherlands
- MIRA Institute for Biomedical Technology and Technical Medicine, Department of Biomaterials Science and Technology, University of Twente, Enschede, The Netherlands
| | - Sjoerd K Bulstra
- University of Groningen, University Medical Center Groningen, Department of Orthopaedic Surgery, Groningen, The Netherlands
| | - Dirk W Grijpma
- University of Groningen, University Medical Center Groningen, W. J. Kolff Institute, Department of Biomedical Engineering, Groningen, The Netherlands
- MIRA Institute for Biomedical Technology and Technical Medicine, Department of Biomaterials Science and Technology, University of Twente, Enschede, The Netherlands
| | - Roel Kuijer
- University of Groningen, University Medical Center Groningen, W. J. Kolff Institute, Department of Biomedical Engineering, Groningen, The Netherlands
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12
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Iatridis JC, Nicoll SB, Michalek AJ, Walter BA, Gupta MS. Role of biomechanics in intervertebral disc degeneration and regenerative therapies: what needs repairing in the disc and what are promising biomaterials for its repair? Spine J 2013; 13:243-62. [PMID: 23369494 PMCID: PMC3612376 DOI: 10.1016/j.spinee.2012.12.002] [Citation(s) in RCA: 219] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2011] [Revised: 07/26/2012] [Accepted: 12/09/2012] [Indexed: 02/03/2023]
Abstract
BACKGROUND CONTEXT Degeneration and injuries of the intervertebral disc (IVD) result in large alterations in biomechanical behaviors. Repair strategies using biomaterials can be optimized based on the biomechanical and biological requirements of the IVD. PURPOSE To review the present literature on the effects of degeneration, simulated degeneration, and injury on biomechanics of the IVD, with special attention paid to needle puncture injuries, which are a pathway for diagnostics and regenerative therapies and the promising biomaterials for disc repair with a focus on how those biomaterials may promote biomechanical repair. STUDY DESIGN A narrative review to evaluate the role of biomechanics on disc degeneration and regenerative therapies with a focus on what biomechanical properties need to be repaired and how to evaluate and accomplish such repairs using biomaterials. Model systems for the screening of such repair strategies are also briefly described. METHODS Articles were selected from two main PubMed searches using keywords: intervertebral AND biomechanics (1,823 articles) and intervertebral AND biomaterials (361 articles). Additional keywords (injury, needle puncture, nucleus pressurization, biomaterials, hydrogel, sealant, tissue engineering) were used to narrow the articles down to the topics most relevant to this review. RESULTS Degeneration and acute disc injuries have the capacity to influence nucleus pulposus (NP) pressurization and annulus fibrosus (AF) integrity, which are necessary for an effective disc function and, therefore, require repair. Needle injection injuries are of particular clinical relevance with the potential to influence disc biomechanics, cellularity, and metabolism, yet these effects are localized or small and more research is required to evaluate and reduce the potential clinical morbidity using such techniques. NP replacement strategies, such as hydrogels, are required to restore the NP pressurization or the lost volume. AF repair strategies including cross-linked hydrogels, fibrous composites, and sealants offer promise for regenerative therapies to restore AF integrity. Tissue engineered IVD structures, as a single implantable construct, may promote greater tissue integration due to the improved repair capacity of the vertebral bone. CONCLUSIONS IVD height, neutral zone characteristics, and torsional biomechanics are sensitive to specific alterations in the NP pressurization and AF integrity and must be addressed for an effective functional repair. Synthetic and natural biomaterials offer promise for NP replacement, AF repair, as an AF sealant, or whole disc replacement. Meeting mechanical and biological compatibilities are necessary for the efficacy and longevity of the repair.
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Affiliation(s)
- James C. Iatridis
- Leni and Peter W. May Department of Orthopaedics, Mount Sinai School of Medicine, New York, NY
| | - Steven B. Nicoll
- Department of Biomedical Engineering, The City College of New York, New York, NY
| | - Arthur J. Michalek
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, VT
| | - Benjamin A. Walter
- Leni and Peter W. May Department of Orthopaedics, Mount Sinai School of Medicine, New York, NY,Department of Biomedical Engineering, The City College of New York, New York, NY
| | - Michelle S. Gupta
- Department of Biomedical Engineering, The City College of New York, New York, NY
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The challenge and advancement of annulus fibrosus tissue engineering. 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; 22:1090-100. [PMID: 23361531 DOI: 10.1007/s00586-013-2663-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2012] [Revised: 12/26/2012] [Accepted: 01/07/2013] [Indexed: 02/07/2023]
Abstract
BACKGROUND Intervertebral disc degeneration, a main cause of back pain, is an endemic problem and a big economic burden for the health care system. Current treatments are symptom relieving but do not address underlying problems-biological and structural deterioration of the disc. Tissue engineering is an emerging approach for the treatment of intervertebral disc degeneration since it restores the functionality of native tissues. Although numerous studies have focused on the nucleus pulposus tissue engineering and achieved successes in laboratory settings, disc tissue engineering without annulus fibrosus for the end stage of disc degeneration is deemed to fail. The purpose of this article is to review the advancement of annulus fibrosus tissue engineering. MATERIAL AND METHODS Relevant articles regarding annulus fibrosus tissue engineering were identified in PubMed and Medline databases. RESULTS The ideal strategy for disc regeneration is to restore the function and integrity of the disc by using biomaterials, native matrices, growth factors, and cells that producing matrices. In the past decades there are tremendous advancement in annulus fibrosus tissue engineering including cell biology, biomaterials, and whole disc replacement. The recent promising results on whole disc tissue engineering-a composite of annulus fibrosus and nucleus pulposus-make the tissue engineering approach more appealing. CONCLUSION Despite the promising results in disc tissue engineering, there is still much work to be done regarding the clinical application.
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Guterl CC, See EY, Blanquer SB, Pandit A, Ferguson SJ, Benneker LM, Grijpma DW, Sakai D, Eglin D, Alini M, Iatridis JC, Grad S. Challenges and strategies in the repair of ruptured annulus fibrosus. Eur Cell Mater 2013; 25:1-21. [PMID: 23283636 PMCID: PMC3655691 DOI: 10.22203/ecm.v025a01] [Citation(s) in RCA: 163] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Lumbar discectomy is the surgical procedure most frequently performed for patients suffering from low back pain and sciatica. Disc herniation as a consequence of degenerative or traumatic processes is commonly encountered as the underlying cause for the painful condition. While discectomy provides favourable outcome in a majority of cases, there are conditions where unmet requirements exist in terms of treatment, such as large disc protrusions with minimal disc degeneration; in these cases, the high rate of recurrent disc herniation after discectomy is a prevalent problem. An effective biological annular repair could improve the surgical outcome in patients with contained disc herniations but otherwise minor degenerative changes. An attractive approach is a tissue-engineered implant that will enable/stimulate the repair of the ruptured annulus. The strategy is to develop three-dimensional scaffolds and activate them by seeding cells or by incorporating molecular signals that enable new matrix synthesis at the defect site, while the biomaterial provides immediate closure of the defect and maintains the mechanical properties of the disc. This review is structured into (1) introduction, (2) clinical problems, current treatment options and needs, (3) biomechanical demands, (4) cellular and extracellular components, (5) biomaterials for delivery, scaffolding and support, (6) pre-clinical models for evaluation of newly developed cell- and material-based therapies, and (7) conclusions. This article highlights that an interdisciplinary approach is necessary for successful development of new clinical methods for annulus fibrosus repair. This will benefit from a close collaboration between research groups with expertise in all areas addressed in this review.
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Affiliation(s)
- Clare C. Guterl
- Department of Orthopaedics, Mount Sinai Medical Centre, New York, NY, USA,Collaborative Research Partner Annulus Fibrosus Rupture Program of AO Foundation, Davos, Switzerland
| | - Eugene Y. See
- Network of Excellence for Functional Biomaterials, National University of Ireland, Galway, Ireland,Collaborative Research Partner Annulus Fibrosus Rupture Program of AO Foundation, Davos, Switzerland
| | - Sebastien B.G. Blanquer
- Department of Biomaterials Science and Technology, University of Twente, Enschede, The Netherlands,Collaborative Research Partner Annulus Fibrosus Rupture Program of AO Foundation, Davos, Switzerland
| | - Abhay Pandit
- Network of Excellence for Functional Biomaterials, National University of Ireland, Galway, Ireland,Collaborative Research Partner Annulus Fibrosus Rupture Program of AO Foundation, Davos, Switzerland
| | - Stephen J. Ferguson
- Institute for Biomechanics, ETH Zurich, Zurich, Switzerland,Collaborative Research Partner Annulus Fibrosus Rupture Program of AO Foundation, Davos, Switzerland
| | - Lorin M. Benneker
- Department of Orthopaedic Surgery, University of Bern, Bern, Switzerland,Collaborative Research Partner Annulus Fibrosus Rupture Program of AO Foundation, Davos, Switzerland
| | - Dirk W. Grijpma
- Department of Biomaterials Science and Technology, University of Twente, Enschede, The Netherlands,Department of Biomedical Engineering, University Medical Centre Groningen and University of Groningen, Groningen, The Netherlands,Collaborative Research Partner Annulus Fibrosus Rupture Program of AO Foundation, Davos, Switzerland
| | - Daisuke Sakai
- Department of Orthopaedic Surgery, Tokai University School of Medicine, Isehara, Kanagawa, Japan,Collaborative Research Partner Annulus Fibrosus Rupture Program of AO Foundation, Davos, Switzerland
| | - David Eglin
- AO Research Institute Davos, Davos, Switzerland,Collaborative Research Partner Annulus Fibrosus Rupture Program of AO Foundation, Davos, Switzerland
| | - Mauro Alini
- AO Research Institute Davos, Davos, Switzerland,Collaborative Research Partner Annulus Fibrosus Rupture Program of AO Foundation, Davos, Switzerland
| | - James C. Iatridis
- Department of Orthopaedics, Mount Sinai Medical Centre, New York, NY, USA,Collaborative Research Partner Annulus Fibrosus Rupture Program of AO Foundation, Davos, Switzerland
| | - Sibylle Grad
- AO Research Institute Davos, Davos, Switzerland,Collaborative Research Partner Annulus Fibrosus Rupture Program of AO Foundation, Davos, Switzerland,Address for correspondence: Sibylle Grad, PhD, AO Research Institute Davos, Clavadelerstrasse 8, 7270 Davos, Switzerland, Telephone Number: +41 81 414 2480, FAX Number: +41 81 414 2288,
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15
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Leung VYL, Tam V, Chan D, Chan BP, Cheung KMC. Tissue engineering for intervertebral disk degeneration. Orthop Clin North Am 2011; 42:575-83, ix. [PMID: 21944593 DOI: 10.1016/j.ocl.2011.07.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Many challenges confront intervertebral disk engineering owing to complexity and the presence of extraordinary stresses. Rebuilding a disk of native function could be useful for removal of the symptoms and correction of altered spine kinematics. Improvement in understanding of disk properties and techniques for disk engineering brings promise to the fabrication of a functional motion segment for the treatment of disk degeneration. Increasing sophistication of techniques available in biomedical sciences will bring its application into clinics. This review provides an account of current progress and challenges of intervertebral disk bioengineering and discusses means to move forward and toward bedside translation.
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Affiliation(s)
- Victor Y L Leung
- Department of Orthopaedics & Traumatology, The University of Hong Kong, Hong Kong SAR, China
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16
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Bron JL, Vonk LA, Smit TH, Koenderink GH. Engineering alginate for intervertebral disc repair. J Mech Behav Biomed Mater 2011; 4:1196-205. [PMID: 21783128 DOI: 10.1016/j.jmbbm.2011.04.002] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2011] [Revised: 04/02/2011] [Accepted: 04/04/2011] [Indexed: 10/18/2022]
Abstract
Alginate is frequently studied as a scaffold for intervertebral disc (IVD) repair, since it closely mimics mechanical and cell-adhesive properties of the nucleus pulposus (NP) of the IVD. The aim of this study was to assess the relation between alginate concentration and scaffold stiffness and find preparation conditions where the viscoelastic behaviour mimics that of the NP. In addition, we measured the effect of variations in scaffold stiffness on the expression of extracellular matrix molecules specific to the NP (proteoglycans and collagen) by native NP cells. We prepared sample discs of different concentrations of alginate (1%-6%) by two different methods, diffusion and in situ gelation. The stiffness increased with increasing alginate concentration, while the loss tangent (dissipative behaviour) remained constant. The diffusion samples were ten-fold stiffer than samples prepared by in situ gelation. Sample discs prepared from 2% alginate by diffusion closely matched the stiffness and loss tangent of the NP. The stiffness of all samples declined upon prolonged incubation in medium, especially for samples prepared by diffusion. The biosynthetic phenotype of native cells isolated from NPs was preserved in alginate matrices up to 4 weeks of culturing. Gene expression levels of extracellular matrix components were insensitive to alginate concentration and corresponding matrix stiffness, likely due to the poor adhesiveness of the cells to alginate. In conclusion, alginate can mimic the viscoelastic properties of the NP and preserve the biosynthetic phenotype of NP cells but certain limitations like long-term stability still have to be addressed.
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Affiliation(s)
- Johannes L Bron
- Department of Orthopaedic Surgery, VU University Medical Center, Amsterdam, The Netherlands.
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17
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Bowles RD, Williams RM, Zipfel WR, Bonassar LJ. Self-assembly of aligned tissue-engineered annulus fibrosus and intervertebral disc composite via collagen gel contraction. Tissue Eng Part A 2010; 16:1339-48. [PMID: 19905878 DOI: 10.1089/ten.tea.2009.0442] [Citation(s) in RCA: 118] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Many cartilaginous tissues such as intervertebral disc (IVD) display a heterogeneous collagen microstructure that results in mechanical anisotropy. These structures are responsible for mechanical function of the tissue and regulate cellular interactions and metabolic responses of cells embedded within these tissues. Using collagen gels seeded with ovine annulus fibrosus cells, constructs of varying structure and heterogeneity were created to mimic the circumferential alignment of the IVD. Alignment was induced within gels by contracting annular gels around an inner boundary using both a polyethylene center and alginate center to create a composite engineered IVD. Collagen alignment and heterogeneity were measured using second harmonic generation microscopy. Decreasing initial collagen density from 2.5 mg/mL to 1 mg/mL produced greater contraction of constructs, resulting in gels that were 55% and 6.2% of the original area after culture, respectively. As a result, more alignment occurred in annular-shaped 1 mg/mL gels compared with 2.5 mg/mL gels (p < 0.05). This alignment was also produced in a composite-engineered IVD with alginate nucleus pulposus. The resulting collagen alignment could promote further aligned collagen development necessary for the creation of a mechanically functional tissue-engineered IVD.
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Affiliation(s)
- Robby D Bowles
- Department of Biomedical Engineering, Cornell University , Ithaca, NY, USA
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18
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Bron JL, Helder MN, Meisel HJ, Van Royen BJ, Smit TH. Repair, regenerative and supportive therapies of the annulus fibrosus: achievements and challenges. 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 2008; 18:301-13. [PMID: 19104850 PMCID: PMC2899423 DOI: 10.1007/s00586-008-0856-x] [Citation(s) in RCA: 145] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/21/2008] [Revised: 09/09/2008] [Accepted: 12/05/2008] [Indexed: 01/07/2023]
Abstract
Lumbar discectomy is a very effective therapy for neurological decompression in patients suffering from sciatica due to hernia nuclei pulposus. However, high recurrence rates and persisting post-operative low back pain in these patients require serious attention. In the past decade, tissue engineering strategies have been developed mainly targeted to the regeneration of the nucleus pulposus (NP) of the intervertebral disc. Accompanying techniques that deal with the damaged annulus fibrous are now increasingly recognised as mandatory in order to prevent re-herniation to increase the potential of NP repair and to confine NP replacement therapies. In the current review, the requirements, achievements and challenges in this quickly emerging field of research are discussed.
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Affiliation(s)
- Johannes Leendert Bron
- Department of Orthopaedic Surgery, VU University Medical Center, Amsterdam, The Netherlands.
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19
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Chan BP, Leong KW. Scaffolding in tissue engineering: general approaches and tissue-specific considerations. 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 2008; 17 Suppl 4:467-79. [PMID: 19005702 DOI: 10.1007/s00586-008-0745-3] [Citation(s) in RCA: 833] [Impact Index Per Article: 52.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2008] [Revised: 07/09/2008] [Accepted: 07/09/2008] [Indexed: 12/19/2022]
Abstract
Scaffolds represent important components for tissue engineering. However, researchers often encounter an enormous variety of choices when selecting scaffolds for tissue engineering. This paper aims to review the functions of scaffolds and the major scaffolding approaches as important guidelines for selecting scaffolds and discuss the tissue-specific considerations for scaffolding, using intervertebral disc as an example.
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Affiliation(s)
- B P Chan
- Medical Engineering Program, Department of Mechanical Engineering, The University of Hong Kong, Room 711, Haking Wong Building, Pokfulam Road, Hong Kong SAR, China.
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20
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Douglas T, Heinemann S, Hempel U, Mietrach C, Knieb C, Bierbaum S, Scharnweber D, Worch H. Characterization of collagen II fibrils containing biglycan and their effect as a coating on osteoblast adhesion and proliferation. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2008; 19:1653-60. [PMID: 17851735 DOI: 10.1007/s10856-007-3250-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2006] [Accepted: 07/27/2007] [Indexed: 05/17/2023]
Abstract
Collagen has been used as a coating material for titanium-based implants for bone contact and as a component of scaffolds for bone tissue engineering. In general collagen type I has been used, however very little attention has been focussed on collagen type II. Collagen-based coatings and scaffolds have been enhanced by the incorporation of the glycosaminoglycan chondroitin sulphate (CS), however the proteglycan biglycan, which is found in bone and contains glycosaminoglycan chains consisting of CS, has not been used as a biomaterial component. The study had the following aims: firstly, five different collagen II preparations were compared with regard to their ability to bind CS and biglycan and the changes in fibril morphology thereby induced. Secondly, the effects of biglycan on the adhesion of primary rat osteoblasts (rO) as well as the proliferation of rO, primary human osteoblasts (hO) and the osteoblast-like cell line 7F2 were studied by culturing the cells on surfaces coated with collagen II fibrils containing biglycan. Fibrils of the collagen II preparation which bound the most biglycan were used to coat titanium surfaces. Bare titanium, titanium coated with collagen II fibrils and titanium coated with collagen II fibrils containing biglycan were compared. It was found that different collagen II preparations showed different affinities for CS and biglycan. In four of the five preparations tested, biglycan reduced fibril diameter, however the ability of a preparation to bind more biglycan did not appear to lead to a greater reduction in fibril diameter. Fibrils containing biglycan promoted the formation of focal adhesions by rO and significantly enhanced the proliferation of hO but not of rO or 7F2 cells. These results should encourage further investigation of biglycan as a component of collagen-based scaffolds and/or coatings.
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Affiliation(s)
- Timothy Douglas
- Institute of Material Science, Max Bergmann Center of Biomaterials, Technische Universität Dresden, 01069 Dresden, Germany.
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21
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Jaasma MJ, Plunkett NA, O’Brien FJ. Design and validation of a dynamic flow perfusion bioreactor for use with compliant tissue engineering scaffolds. J Biotechnol 2008; 133:490-6. [DOI: 10.1016/j.jbiotec.2007.11.010] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2007] [Revised: 11/12/2007] [Accepted: 11/19/2007] [Indexed: 10/22/2022]
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22
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Wan Y, Feng G, Shen FH, Balian G, Laurencin CT, Li X. Novel biodegradable poly(1,8-octanediol malate) for annulus fibrosus regeneration. Macromol Biosci 2008; 7:1217-24. [PMID: 17683110 DOI: 10.1002/mabi.200700053] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
A novel elastic scaffold that simulates the deformability of annulus fibrosus (AF) and has good biocompatibility was developed. The scaffold was formed of a malic acid-based polyester poly(1,8-octanediol malate) (POM), which was synthesized by direct polycondensation. The tensile strength of POM gradually increased with the extension of the polymerization time, while the degradation rate decreased. Rat AF cells proliferated on the POM films and maintained their phenotype. The 3D scaffold also supported the growth of the AF cells, as confirmed by Safranin-O and type II collagen staining. POM also demonstrated a good biocompatibility in an in vivo foreign body response assay, an important prerequisite for tissue engineering applications. This study suggests that elastic POM scaffold may be an ideal candidate for AF tissue engineering.
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Affiliation(s)
- Yuqing Wan
- Department of Orthopaedic Surgery, University of Virginia School of Medicine, Charlottesville, Virginia 22908, USA
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23
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Wan Y, Feng G, Shen FH, Laurencin CT, Li X. Biphasic scaffold for annulus fibrosus tissue regeneration. Biomaterials 2007; 29:643-52. [PMID: 17997480 DOI: 10.1016/j.biomaterials.2007.10.031] [Citation(s) in RCA: 106] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2007] [Accepted: 10/15/2007] [Indexed: 11/17/2022]
Abstract
Intervertebral disc (IVD) degeneration is the major cause of lower back pain, while the currently available treatments are symptomatic rather than curative. Tissue engineering is a powerful therapeutic strategy that can restore the normal biomechanical motion of the human spine. The ability of a biphasic elastic scaffold to structurally and elastically simulate the annulus fibrosus (AF) tissue of the IVD was explored. The outer phase of the scaffold was a ring-shaped demineralized bone matrix gelatin (BMG) extracted from cortical bone, which mimicks the type I collagen structure and ligamentous properties of outer AF. The inner phase of the scaffold was a bio-biomaterial poly(polycaprolactone triol malate) (PPCLM) orientated in concentric sheets and seeded with chondrocytes to recapitulate the inner layer of the AF, which is rich in type II collagen and proteoglycan. The mechanical properties and degradation of PPCLM could be adjusted by controlling the post-polymerization time of the pre-polymer. PPCLM also demonstrated good biocompatibility in a foreign body response in vivo assay. Incorporation of BMG into the scaffold enhanced the compressive strength compared with PPCLM alone. In addition, the tensile stress of the BMG/PPCLM scaffold was 50-fold greater than that of PPCLM alone, and close to that of normal rabbit AF. Finally, the biphasic scaffold supported the growth of rabbit chondrocytes, as confirmed by Safranin-O and type II collagen immunostaining. The excellent mechanical properties and biocompatibility of the BMG/PPCLM scaffold make it a promising candidate for AF repair.
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Affiliation(s)
- Yuqing Wan
- Department of Orthopaedic Surgery, University of Virginia School of Medicine, Charlottesville, VA 22908, USA
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Nerurkar NL, Elliott DM, Mauck RL. Mechanics of oriented electrospun nanofibrous scaffolds for annulus fibrosus tissue engineering. J Orthop Res 2007; 25:1018-28. [PMID: 17457824 DOI: 10.1002/jor.20384] [Citation(s) in RCA: 164] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Engineering a functional replacement for the annulus fibrosus (AF) of the intervertebral disc is contingent upon recapitulation of AF structure, composition, and mechanical properties. In this study, we propose a new paradigm for AF tissue engineering that focuses on the reconstitution of anatomic fiber architecture and uses constitutive modeling to evaluate construct function. A modified electrospinning technique was utilized to generate aligned nanofibrous polymer scaffolds for engineering the basic functional unit of the AF, a single lamella. Scaffolds were tested in uniaxial tension at multiple fiber orientations, demonstrating a nonlinear dependence of modulus on fiber angle that mimicked the nonlinearity and anisotropy of native AF. A homogenization model previously applied to native AF successfully described scaffold mechanical response, and parametric studies demonstrated that nonfibrillar matrix, along with fiber connectivity, are key contributors to tensile mechanics for engineered AF. We demonstrated that AF cells orient themselves along the aligned scaffolds and deposit matrix that contributes to construct mechanics under loading conditions relevant to the in vivo environment. The homogenization model was applied to cell-seeded constructs and provided quantitative measures for the evolution of matrix and interfibrillar interactions. Finally, the model demonstrated that at fiber angles of the AF (28 degrees -44 degrees ), engineered material behaved much like native tissue, suggesting that engineered constructs replicate the physiologic behavior of the single AF lamella. Constitutive modeling provides a powerful tool for analysis of engineered AF neo-tissue and native AF tissue alike, highlighting key mechanical design criteria for functional AF tissue engineering.
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Affiliation(s)
- Nandan L Nerurkar
- McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, University of Pennsylvania, 424 Stemmler Hall, 36th Street and Hamilton Walk, Philadelphia, Pennsylvania 19104-6081, USA
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