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Li Y, Chen A, Hong A, Xiong S, Chen X, Xie Q. Shark Cartilage-Derived Anti-Angiogenic Peptide Inhibits Corneal Neovascularization. Bioengineering (Basel) 2024; 11:693. [PMID: 39061775 PMCID: PMC11273382 DOI: 10.3390/bioengineering11070693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2024] [Revised: 07/01/2024] [Accepted: 07/03/2024] [Indexed: 07/28/2024] Open
Abstract
Corneal neovascularization is a significant cause of vision loss, often resulting in corneal clouding and chronic inflammation. Shark cartilage is widely recognized as a significant natural source of anti-angiogenic compounds. Our previous studies have shown that a polypeptide from white-spotted catshark (Chiloscyllium plagiosum Bonnet) has the potential to inhibit the angiogenesis of breast tumors. This study applied this peptide (SAIF) to a corneal alkali injury model to assess its effect on corneal neovascularization. Results revealed that SAIF inhibits endothelial cell proliferation, migration, and tube formation. SAIF inhibited VEGF-induced angiogenesis in the matrigel plug. Using the corneal alkali injury model, SAIF significantly inhibited corneal vascular neovascularization in mice. We found that SAIF not only significantly inhibited the upregulation of pro-angiogenic factors such as VEGF, bFGF, and PDGF expression induced by alkali injury, but also promoted the expression of anti-angiogenesis factor PEDF. Moreover, we also analyzed the MMPs and TIMPs involved in extracellular matrix (ECM) remodeling, angiogenesis, and lymphangiogenesis. We found that SAIF treatment inhibited the expression of pro-angiogenic factors like MMP1, MMP2, MMP3, MMP9, MMP13, and MMP14, and promoted the expression of anti-angiogenesis factors such as MMP7, TIMP1, TIMP2, and TIMP3. In conclusion, SAIF acts as an anti-angiogenic factor to inhibit the proliferation, migration, and tube formation of endothelial cells, inhibit pro-angiogenic factors, promote anti-angiogenic factors, and regulate the expression of MMPs, ultimately inhibiting corneal neovascularization.
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Affiliation(s)
- Yunxian Li
- College of Life Science and Technology, Jinan University, Guangzhou 510632, China; (Y.L.); (A.H.); (S.X.)
| | - Aoke Chen
- National Engineering Research Center of Genetic Medicine, Guangzhou 510632, China;
- Guangdong Jida Engineering Research Center of Genetic Medicine Co., Ltd., Guangzhou 510535, China
| | - An Hong
- College of Life Science and Technology, Jinan University, Guangzhou 510632, China; (Y.L.); (A.H.); (S.X.)
- National Engineering Research Center of Genetic Medicine, Guangzhou 510632, China;
| | - Sheng Xiong
- College of Life Science and Technology, Jinan University, Guangzhou 510632, China; (Y.L.); (A.H.); (S.X.)
- National Engineering Research Center of Genetic Medicine, Guangzhou 510632, China;
| | - Xiaojia Chen
- College of Life Science and Technology, Jinan University, Guangzhou 510632, China; (Y.L.); (A.H.); (S.X.)
- National Engineering Research Center of Genetic Medicine, Guangzhou 510632, China;
| | - Qiuling Xie
- College of Life Science and Technology, Jinan University, Guangzhou 510632, China; (Y.L.); (A.H.); (S.X.)
- National Engineering Research Center of Genetic Medicine, Guangzhou 510632, China;
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2
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Tu H, Gao Q, Zhou Y, Peng L, Wu D, Zhang D, Yang J. The role of sirtuins in intervertebral disc degeneration: Mechanisms and therapeutic potential. J Cell Physiol 2024. [PMID: 38922861 DOI: 10.1002/jcp.31328] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2023] [Revised: 04/27/2024] [Accepted: 05/13/2024] [Indexed: 06/28/2024]
Abstract
Intervertebral disc degeneration (IDD) is one of the main causes of low back pain, which affects the patients' quality of life and health and imposes a significant socioeconomic burden. Despite great efforts made by researchers to understand the pathogenesis of IDD, effective strategies for preventing and treating this disease remain very limited. Sirtuins are a highly conserved family of (NAD+)-dependent deacetylases in mammals that are involved in a variety of metabolic processes in vivo. In recent years, sirtuins have attracted much attention owing to their regulatory roles in IDD on physiological activities such as inflammation, apoptosis, autophagy, aging, oxidative stress, and mitochondrial function. At the same time, many studies have explored the therapeutic effects of sirtuins-targeting activators or micro-RNA in IDD. This review summarizes the molecular pathways of sirtuins involved in IDD, and summarizes the therapeutic role of activators or micro-RNA targeting Sirtuins in IDD, as well as the current limitations and challenges, with a view to provide possible solutions for the treatment of IDD.
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Affiliation(s)
- Heng Tu
- State Key Laboratory of Oral Diseases & National Center for Stomatology & National Clinical Research Center for Oral Diseases, Department of Cariology and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - Qian Gao
- State Key Laboratory of Oral Diseases & National Center for Stomatology & National Clinical Research Center for Oral Diseases, Department of Cariology and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - Yumeng Zhou
- State Key Laboratory of Oral Diseases & National Center for Stomatology & National Clinical Research Center for Oral Diseases, Department of Cariology and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - Li Peng
- Key Laboratory of Bio-Resource & Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, Sichuan, China
| | - Dan Wu
- State Key Laboratory of Oral Diseases & National Center for Stomatology & National Clinical Research Center for Oral Diseases, Department of Cariology and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
| | - Demao Zhang
- Institute of Biomedical Engineering, West China School of Basic Medical Sciences & Forensic Medicine, Sichuan University, Chengdu, Sichuan, China
| | - Jing Yang
- State Key Laboratory of Oral Diseases & National Center for Stomatology & National Clinical Research Center for Oral Diseases, Department of Cariology and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, China
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3
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Wu Z, Sun H, Zhang Y, Xiao L, Zhao Q. Biomechanical Finite Element Analysis of Percutaneous Endoscopic Lumbar Discectomy via a Transforaminal Approach. World Neurosurg 2024; 185:e291-e298. [PMID: 37898267 DOI: 10.1016/j.wneu.2023.10.108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2023] [Accepted: 10/23/2023] [Indexed: 10/30/2023]
Abstract
OBJECTIVE Based on the previously established 3-dimensional model, this study uses the finite element analytical method to observe the effects of superior articular process resection and intervertebral discectomy on the stress of the surgical segment under different motion states. METHODS A validated L3-S1 finite element model was modified for simulation. And on the basis of the normal lumbar spine model, the superior articular process and discs of different parts of L4-L5 were simulated for resection. The resection models were divided into 6 groups, and the stress characteristics of articular process and discs of the lumbar spine under different postoperative motion conditions were examined under the same loading conditions. RESULTS Simultaneous resection of the tip and base of the superior articular process increased the stress on the facet joint under various motion states compared with separate resections. In addition, the fewer herniated discs that are removed, the smaller the increase in facet joint stress. excision of the tip of the superior articular process caused a smaller stress increase in the facet joint than excision of the base under the forward bending and right-lateral flexion, and the opposite results were found under left-lateral flexion, posterior extension, and rotation. Resection of the tip of the superior articular process increases disc stress more than resection of the base of the superior articular process. CONCLUSIONS Select resection of the superior articular process base as much as possible to expose the target of the disc. And minimize annulus damage and disc removal.
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Affiliation(s)
- Zhongxuan Wu
- Department of Spine Surgery, Yijishan Hospital, The First Affliated Hospital of Wannan Medical College, Wuhu City, Anhui Province, China
| | - Hongzhou Sun
- Department of Spine Surgery, Yijishan Hospital, The First Affliated Hospital of Wannan Medical College, Wuhu City, Anhui Province, China
| | - Yu Zhang
- Department of Spine Surgery, Yijishan Hospital, The First Affliated Hospital of Wannan Medical College, Wuhu City, Anhui Province, China
| | - Liang Xiao
- Department of Spine Surgery, Yijishan Hospital, The First Affliated Hospital of Wannan Medical College, Wuhu City, Anhui Province, China
| | - Quanlai Zhao
- Department of Spine Surgery, Yijishan Hospital, The First Affliated Hospital of Wannan Medical College, Wuhu City, Anhui Province, China.
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Wang Y, Li Q, Li H, Yang X, Fang H, Bi R, Zhu S. Heterogeneous Characteristics of the CD90 + Progenitors in the Fibrocartilage of Different Joints. Cartilage 2023:19476035231200359. [PMID: 37750508 DOI: 10.1177/19476035231200359] [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] [Indexed: 09/27/2023] Open
Abstract
OBJECTIVE This study aimed to isolate and compare the mesenchymal stem cell characteristics of CD90+ cells from different fibrocartilage tissues in the temporomandibular joint (TMJ), the knee joint, and the intervertebral joint to further understand the similarities and differences of these 4 fibrocartilage tissues. METHODS CD90+ cells were isolated from TMJ disc, condylar cartilage, meniscus, and intervertebral disc by using magnetic-activated cell sorting. Cellular assays including 4.5-ethynyl-2'-deoxyuridine labeling, multilineage differentiation, colony formation, and cell migration were conducted to compare their mesenchymal stem cell characteristics. Immunofluorescent staining was performed for observing the expression of actively proliferating CD90+ cells within the tissues. H&E staining and Safranine O staining were used to compare the histological features. RESULTS The CD90+ cells derived from these 4 fibrocartilage tissues exhibited comparable cell proliferation abilities. However, the cells from the TMJ disc displayed limited multilineage differentiation potential, colony formation, and cell migration abilities in comparison with the cells from the other fibrocartilage tissues. In vivo, there was relatively more abundant expression of CD90+ cells in the TMJ disc during the early postnatal stage. The limited EDU+ cell numbers signified a low proliferation capacity of CD90+ cells in the TMJ disc. In addition, we observed a significant decrease in cell density and a restriction in the synthesis of extracellular proteoglycans in the TMJ disc. CONCLUSION Our study highlights the spatial heterogeneity of CD90+ cells in the fibrocartilages of different joint tissues, which may contribute to the limited cartilage repair capacity in the TMJ disc.
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Affiliation(s)
- Yiru Wang
- State Key Laboratory of Oral Diseases & National Center for Stomatology & National Clinical Research Center for Oral Diseases, Department of Orthognathic and Temporomandibular Joint Surgery, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Qianli Li
- State Key Laboratory of Oral Diseases & National Center for Stomatology & National Clinical Research Center for Oral Diseases, Department of Orthognathic and Temporomandibular Joint Surgery, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Haohan Li
- State Key Laboratory of Oral Diseases & National Center for Stomatology & National Clinical Research Center for Oral Diseases, Department of Orthognathic and Temporomandibular Joint Surgery, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Xianni Yang
- State Key Laboratory of Oral Diseases & National Center for Stomatology & National Clinical Research Center for Oral Diseases, Department of Orthognathic and Temporomandibular Joint Surgery, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Han Fang
- State Key Laboratory of Oral Diseases & National Center for Stomatology & National Clinical Research Center for Oral Diseases, Department of Orthognathic and Temporomandibular Joint Surgery, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Ruiye Bi
- State Key Laboratory of Oral Diseases & National Center for Stomatology & National Clinical Research Center for Oral Diseases, Department of Orthognathic and Temporomandibular Joint Surgery, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Songsong Zhu
- State Key Laboratory of Oral Diseases & National Center for Stomatology & National Clinical Research Center for Oral Diseases, Department of Orthognathic and Temporomandibular Joint Surgery, West China Hospital of Stomatology, Sichuan University, Chengdu, China
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Core-shell oxygen-releasing fibers for annulus fibrosus repair in the intervertebral disc of rats. Mater Today Bio 2023; 18:100535. [PMID: 36654965 PMCID: PMC9841168 DOI: 10.1016/j.mtbio.2022.100535] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Revised: 12/15/2022] [Accepted: 12/26/2022] [Indexed: 01/05/2023] Open
Abstract
The repair of annulus fibrosus (AF) defect after discectomy in the intervertebral disc (IVD) has presented a challenge over the past decade. Hostile microenvironments in the IVD, including, compression and hypoxia, are critical issues that require special attention. Till date, little information is available on potential strategies to cope with the hypoxia dilemma in AF defect sites. In this study, perfluorotributylamine (PFTBA) core-shell fibers were fabricated by coaxial electrospinning to construct oxygen-releasing scaffold for promoting endogenous repair in the AF after discectomy. We demonstrated that PFTBA fibers (10% chitosan, chitosan: PCL, 1:6) could release oxygen for up to 144 h. The oxygen released from PFTBA fibers was found to protect annulus fibrosus stem cells (AFSCs) from hypoxia-induced apoptosis. In addition, the PFTBA fibers were able to promote proliferation, migration and extracellular matrix (ECM) production in AFSCs under hypoxia, highlighting their therapeutic potential in AF defect repair. Subsequent in vivo studies demonstrated that oxygen-supplying fibers were capable of ameliorating disc degeneration after discectomy, which was evidenced by improved disc height and morphological integrity in rats with the oxygen-releasing scaffolds. Further transcriptome analysis indicated that differential expression genes (DEGs) were enriched in "oxygen transport" and "angiogenesis", which likely contributed to their beneficial effect on endogenous AF regeneration. In summary, the oxygen-releasing scaffold provides novel insights into the oxygen regulation by bioactive materials and raises the therapeutic possibility of oxygen supply strategies for defect repair in AF, as well as other aerobic tissues.
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Targeting Ferroptosis Holds Potential for Intervertebral Disc Degeneration Therapy. Cells 2022; 11:cells11213508. [PMID: 36359904 PMCID: PMC9653619 DOI: 10.3390/cells11213508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 11/02/2022] [Accepted: 11/03/2022] [Indexed: 11/09/2022] Open
Abstract
Intervertebral disc degeneration (IVDD) is a common pathological condition responsible for lower back pain, which can significantly increase economic and social burdens. Although considerable efforts have been made to identify potential mechanisms of disc degeneration, the treatment of IVDD is not satisfactory. Ferroptosis, a recently reported form of regulated cell death (RCD), is characterized by iron-dependent lipid peroxidation and has been demonstrated to be responsible for a variety of degenerative diseases. Accumulating evidence suggests that ferroptosis is implicated in IVDD by decreasing viability and increasing extracellular matrix degradation of nucleus pulposus cells, annulus fibrosus cells, or endplate chondrocytes. In this review, we summarize the literature regarding ferroptosis of intervertebral disc cells and discuss its molecular pathways and biomarkers for treating IVDD. Importantly, ferroptosis is verified as a promising therapeutic target for IVDD.
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Importance of Matrix Cues on Intervertebral Disc Development, Degeneration, and Regeneration. Int J Mol Sci 2022; 23:ijms23136915. [PMID: 35805921 PMCID: PMC9266338 DOI: 10.3390/ijms23136915] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 06/17/2022] [Accepted: 06/20/2022] [Indexed: 01/25/2023] Open
Abstract
Back pain is one of the leading causes of disability worldwide and is frequently caused by degeneration of the intervertebral discs. The discs’ development, homeostasis, and degeneration are driven by a complex series of biochemical and physical extracellular matrix cues produced by and transmitted to native cells. Thus, understanding the roles of different cues is essential for designing effective cellular and regenerative therapies. Omics technologies have helped identify many new matrix cues; however, comparatively few matrix molecules have thus far been incorporated into tissue engineered models. These include collagen type I and type II, laminins, glycosaminoglycans, and their biomimetic analogues. Modern biofabrication techniques, such as 3D bioprinting, are also enabling the spatial patterning of matrix molecules and growth factors to direct regional effects. These techniques should now be applied to biochemically, physically, and structurally relevant disc models incorporating disc and stem cells to investigate the drivers of healthy cell phenotype and differentiation. Such research will inform the development of efficacious regenerative therapies and improved clinical outcomes.
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8
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Molladavoodi S, DeWitte‐Orr SJ, Gregory DE. An in vitro 3D annulus fibrosus cell culture model with type I collagen: An examination of cell-matrix interactions. JOR Spine 2022; 5:e1193. [PMID: 35386752 PMCID: PMC8966884 DOI: 10.1002/jsp2.1193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 01/11/2022] [Accepted: 01/13/2022] [Indexed: 11/07/2022] Open
Abstract
Background Disorders of the intervertebral disc (IVD) are widely known to result in low back pain; one of the most common debilitating conditions worldwide. As a multifaceted condition, both inflammatory environment and mechanical factors can play a crucial role in IVD damage, and in particular, in the annulus fibrosus (AF), the highly collagenous outer ring of the IVD. As a result, a better understanding of how cells from the IVD, and specifically the AF, interact and respond to their environment is imperative. Goal The goal of this study is to use collagen type I as an in vitro three-dimensional extracellular matrix for AF cells of IVD and briefly examine both the cellular and mechanical effect of exposure to an inflammatory stimulant. Methods We utilized type I collagen as a 3D in vitro model material for culturing AF cells of Sprague Dawley rat tail IVDs. Results We showed that the cultured cells are viable and metabolically active; these cells also induced a distinct and significant contraction on their collagen matrix. Furthermore, to demonstrate potential versatility of our model our model and its versatility, we used lipopolysaccharide (LPS), as a known inflammatory stimulant in IVDs, to manipulate the cells and their interaction. LPS treatment resulted in detectable changes to the contraction cells induced on the collagen matrix and affected the mechanical properties of these constructs.
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Affiliation(s)
- Sara Molladavoodi
- Department of Kinesiology and Physical EducationWilfrid Laurier UniversityWaterlooOntarioCanada
| | - Stephanie J. DeWitte‐Orr
- Department of Health SciencesWilfrid Laurier UniversityWaterlooOntarioCanada
- Department of BiologyWilfrid Laurier UniversityWaterlooOntarioCanada
| | - Diane E. Gregory
- Department of Kinesiology and Physical EducationWilfrid Laurier UniversityWaterlooOntarioCanada
- Department of Health SciencesWilfrid Laurier UniversityWaterlooOntarioCanada
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The Role of Oxidative Stress in Intervertebral Disc Degeneration. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2022; 2022:2166817. [PMID: 35069969 PMCID: PMC8769842 DOI: 10.1155/2022/2166817] [Citation(s) in RCA: 55] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 11/21/2021] [Accepted: 12/04/2021] [Indexed: 12/22/2022]
Abstract
Intervertebral disc degeneration is a very common type of degenerative disease causing severe socioeconomic impact, as well as a major cause of discogenic low back pain and herniated discs, placing a heavy burden on patients and the clinicians who treat them. IDD is known to be associating with a complex process involving in extracellular matrix and cellular damage, and in recent years, there is increasing evidence that oxidative stress is an important activation mechanism of IDD and that reactive oxygen and reactive nitrogen species regulate matrix metabolism, proinflammatory phenotype, autophagy and senescence in intervertebral disc cells, apoptosis, autophagy, and senescence. Despite the tremendous efforts of researchers within the field of IDD pathogenesis, the proven strategies to prevent and treat this disease are still very limited. Up to now, several antioxidants have been proved to be effective for alleviating IDD. In this article, we discussed that oxidative stress accelerates disc degeneration by influencing aging, inflammation, autophagy, and DNA methylation, and summarize some antioxidant therapeutic measures for IDD, indicating that antioxidant therapy for disc degeneration holds excellent promise.
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Raza A, Michalek AJ. Radial trend in murine annulus fibrosus fiber orientation is best explained by vertebral growth. 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 2021; 30:3450-3456. [PMID: 34561728 DOI: 10.1007/s00586-021-06999-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 09/06/2021] [Accepted: 09/14/2021] [Indexed: 01/05/2023]
Abstract
PURPOSE The intervertebral disc (IVD) annulus fibrosus (AF) is composed of concentric lamellae with alternating right- and left-handed helically oriented collagen fiber bundles. This arrangement results in anisotropic material properties, which depend on local fiber orientations. Prior measurements of fiber inclination angles in human lumbar and bovine caudal IVDs found a significantly higher inclination angle in the inner AF than outer, though it is currently unknown if this pattern is conserved in smaller mammalian species. Additionally, the physical mechanism behind this pattern remains un-determined. METHODS In this study, AF fiber angles were measured histologically in murine caudal IVDs and compared to previously published values from bovine caudal IVDs. Fiber angles were also predicted using three theoretical models, including two based on adaptation to internal swelling pressure and one based on vertebral body growth. RESULTS Fiber angle was found to significantly decrease from 49.5 ± 3.8° in the inner AF to 34.5 ± 6.6° in the outer AF. While steeper than in bovine discs at all locations, the trend with radial position was comparable between species. This trend was best fit by growth-based model and opposite of that predicted by the pressure vessel models. CONCLUSION Trends in AF fiber orientation are conserved between mammalian species. Modeling results suggest that the AF tissue microstructure is more likely to be driven by adjacent vertebral body growth than adapted for optimal mechanical performance.
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Affiliation(s)
- Ali Raza
- Department of Mechanical and Aeronautical Engineering, Clarkson University, Box 5725, Potsdam, NY, 13699, USA
| | - Arthur J Michalek
- Department of Mechanical and Aeronautical Engineering, Clarkson University, Box 5725, Potsdam, NY, 13699, USA.
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11
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Gan Y, He J, Zhu J, Xu Z, Wang Z, Yan J, Hu O, Bai Z, Chen L, Xie Y, Jin M, Huang S, Liu B, Liu P. Spatially defined single-cell transcriptional profiling characterizes diverse chondrocyte subtypes and nucleus pulposus progenitors in human intervertebral discs. Bone Res 2021; 9:37. [PMID: 34400611 PMCID: PMC8368097 DOI: 10.1038/s41413-021-00163-z] [Citation(s) in RCA: 68] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Revised: 04/30/2021] [Accepted: 06/10/2021] [Indexed: 02/07/2023] Open
Abstract
A comprehensive understanding of the cellular heterogeneity and molecular mechanisms underlying the development, homeostasis, and disease of human intervertebral disks (IVDs) remains challenging. Here, the transcriptomic landscape of 108 108 IVD cells was mapped using single-cell RNA sequencing of three main compartments from young and adult healthy IVDs, including the nucleus pulposus (NP), annulus fibrosus, and cartilage endplate (CEP). The chondrocyte subclusters were classified based on their potential regulatory, homeostatic, and effector functions in extracellular matrix (ECM) homeostasis. Notably, in the NP, a PROCR+ resident progenitor population showed enriched colony-forming unit-fibroblast (CFU-F) activity and trilineage differentiation capacity. Finally, intercellular crosstalk based on signaling network analysis uncovered that the PDGF and TGF-β cascades are important cues in the NP microenvironment. In conclusion, a single-cell transcriptomic atlas that resolves spatially regulated cellular heterogeneity together with the critical signaling that underlies homeostasis will help to establish new therapeutic strategies for IVD degeneration in the clinic.
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Affiliation(s)
- Yibo Gan
- grid.410570.70000 0004 1760 6682Department of Spine Surgery, Center of Orthopedics, Daping Hospital, Army Medical University (Third Military Medical University), Chongqing, China ,grid.410570.70000 0004 1760 6682State Key Laboratory of Trauma, Burns and Combined Injury, Army Medical University (Third Military Medical University), Chongqing, China
| | - Jian He
- grid.410740.60000 0004 1803 4911State Key Laboratory of Proteomics, Academy of Military Medical Sciences, Academy of Military Sciences, Beijing, China
| | - Jun Zhu
- grid.410570.70000 0004 1760 6682Department of Spine Surgery, Center of Orthopedics, Daping Hospital, Army Medical University (Third Military Medical University), Chongqing, China
| | - Zhengyang Xu
- grid.410740.60000 0004 1803 4911State Key Laboratory of Proteomics, Academy of Military Medical Sciences, Academy of Military Sciences, Beijing, China
| | - Zhong Wang
- grid.410570.70000 0004 1760 6682Department of Spine Surgery, Center of Orthopedics, Daping Hospital, Army Medical University (Third Military Medical University), Chongqing, China
| | - Jing Yan
- grid.410740.60000 0004 1803 4911State Key Laboratory of Proteomics, Academy of Military Medical Sciences, Academy of Military Sciences, Beijing, China
| | - Ou Hu
- grid.410570.70000 0004 1760 6682Department of Spine Surgery, Center of Orthopedics, Daping Hospital, Army Medical University (Third Military Medical University), Chongqing, China
| | - Zhijie Bai
- grid.410740.60000 0004 1803 4911State Key Laboratory of Proteomics, Academy of Military Medical Sciences, Academy of Military Sciences, Beijing, China
| | - Lin Chen
- grid.410570.70000 0004 1760 6682Center of Bone Metabolism and Repair, State Key Laboratory of Trauma, Burns and Combined Injury, Trauma Center, Research Institute of Surgery, Laboratory for the Prevention and Rehabilitation of Military Training Related Injuries, Daping Hospital, Army Medical University (Third Military Medical University), Chongqing, China
| | - Yangli Xie
- grid.410570.70000 0004 1760 6682Center of Bone Metabolism and Repair, State Key Laboratory of Trauma, Burns and Combined Injury, Trauma Center, Research Institute of Surgery, Laboratory for the Prevention and Rehabilitation of Military Training Related Injuries, Daping Hospital, Army Medical University (Third Military Medical University), Chongqing, China
| | - Min Jin
- grid.410570.70000 0004 1760 6682Center of Bone Metabolism and Repair, State Key Laboratory of Trauma, Burns and Combined Injury, Trauma Center, Research Institute of Surgery, Laboratory for the Prevention and Rehabilitation of Military Training Related Injuries, Daping Hospital, Army Medical University (Third Military Medical University), Chongqing, China
| | - Shuo Huang
- grid.410570.70000 0004 1760 6682Center of Bone Metabolism and Repair, State Key Laboratory of Trauma, Burns and Combined Injury, Trauma Center, Research Institute of Surgery, Laboratory for the Prevention and Rehabilitation of Military Training Related Injuries, Daping Hospital, Army Medical University (Third Military Medical University), Chongqing, China
| | - Bing Liu
- grid.410740.60000 0004 1803 4911State Key Laboratory of Proteomics, Academy of Military Medical Sciences, Academy of Military Sciences, Beijing, China ,grid.11135.370000 0001 2256 9319State Key Laboratory of Experimental Hematology, Institute of Hematology, Fifth Medical Center of Chinese PLA General Hospital, Beijing, China ,grid.258164.c0000 0004 1790 3548Key Laboratory for Regenerative Medicine of Ministry of Education, Institute of Hematology, School of Medicine, Jinan University, Guangzhou, China
| | - Peng Liu
- grid.410570.70000 0004 1760 6682Department of Spine Surgery, Center of Orthopedics, Daping Hospital, Army Medical University (Third Military Medical University), Chongqing, China ,grid.410570.70000 0004 1760 6682State Key Laboratory of Trauma, Burns and Combined Injury, Army Medical University (Third Military Medical University), Chongqing, China
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12
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Gan Y, He J, Zhu J, Xu Z, Wang Z, Yan J, Hu O, Bai Z, Chen L, Xie Y, Jin M, Huang S, Liu B, Liu P. Spatially defined single-cell transcriptional profiling characterizes diverse chondrocyte subtypes and nucleus pulposus progenitors in human intervertebral discs. Bone Res 2021; 9:37. [PMID: 34400611 PMCID: PMC8368097 DOI: 10.1038/s41413-021-00163-z+10.1038/s41413-021-00163-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Revised: 04/30/2021] [Accepted: 06/10/2021] [Indexed: 01/21/2024] Open
Abstract
A comprehensive understanding of the cellular heterogeneity and molecular mechanisms underlying the development, homeostasis, and disease of human intervertebral disks (IVDs) remains challenging. Here, the transcriptomic landscape of 108 108 IVD cells was mapped using single-cell RNA sequencing of three main compartments from young and adult healthy IVDs, including the nucleus pulposus (NP), annulus fibrosus, and cartilage endplate (CEP). The chondrocyte subclusters were classified based on their potential regulatory, homeostatic, and effector functions in extracellular matrix (ECM) homeostasis. Notably, in the NP, a PROCR+ resident progenitor population showed enriched colony-forming unit-fibroblast (CFU-F) activity and trilineage differentiation capacity. Finally, intercellular crosstalk based on signaling network analysis uncovered that the PDGF and TGF-β cascades are important cues in the NP microenvironment. In conclusion, a single-cell transcriptomic atlas that resolves spatially regulated cellular heterogeneity together with the critical signaling that underlies homeostasis will help to establish new therapeutic strategies for IVD degeneration in the clinic.
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Affiliation(s)
- Yibo Gan
- Department of Spine Surgery, Center of Orthopedics, Daping Hospital, Army Medical University (Third Military Medical University), Chongqing, China
- State Key Laboratory of Trauma, Burns and Combined Injury, Army Medical University (Third Military Medical University), Chongqing, China
| | - Jian He
- State Key Laboratory of Proteomics, Academy of Military Medical Sciences, Academy of Military Sciences, Beijing, China
| | - Jun Zhu
- Department of Spine Surgery, Center of Orthopedics, Daping Hospital, Army Medical University (Third Military Medical University), Chongqing, China
| | - Zhengyang Xu
- State Key Laboratory of Proteomics, Academy of Military Medical Sciences, Academy of Military Sciences, Beijing, China
| | - Zhong Wang
- Department of Spine Surgery, Center of Orthopedics, Daping Hospital, Army Medical University (Third Military Medical University), Chongqing, China
| | - Jing Yan
- State Key Laboratory of Proteomics, Academy of Military Medical Sciences, Academy of Military Sciences, Beijing, China
| | - Ou Hu
- Department of Spine Surgery, Center of Orthopedics, Daping Hospital, Army Medical University (Third Military Medical University), Chongqing, China
| | - Zhijie Bai
- State Key Laboratory of Proteomics, Academy of Military Medical Sciences, Academy of Military Sciences, Beijing, China
| | - Lin Chen
- Center of Bone Metabolism and Repair, State Key Laboratory of Trauma, Burns and Combined Injury, Trauma Center, Research Institute of Surgery, Laboratory for the Prevention and Rehabilitation of Military Training Related Injuries, Daping Hospital, Army Medical University (Third Military Medical University), Chongqing, China
| | - Yangli Xie
- Center of Bone Metabolism and Repair, State Key Laboratory of Trauma, Burns and Combined Injury, Trauma Center, Research Institute of Surgery, Laboratory for the Prevention and Rehabilitation of Military Training Related Injuries, Daping Hospital, Army Medical University (Third Military Medical University), Chongqing, China
| | - Min Jin
- Center of Bone Metabolism and Repair, State Key Laboratory of Trauma, Burns and Combined Injury, Trauma Center, Research Institute of Surgery, Laboratory for the Prevention and Rehabilitation of Military Training Related Injuries, Daping Hospital, Army Medical University (Third Military Medical University), Chongqing, China
| | - Shuo Huang
- Center of Bone Metabolism and Repair, State Key Laboratory of Trauma, Burns and Combined Injury, Trauma Center, Research Institute of Surgery, Laboratory for the Prevention and Rehabilitation of Military Training Related Injuries, Daping Hospital, Army Medical University (Third Military Medical University), Chongqing, China
| | - Bing Liu
- State Key Laboratory of Proteomics, Academy of Military Medical Sciences, Academy of Military Sciences, Beijing, China.
- State Key Laboratory of Experimental Hematology, Institute of Hematology, Fifth Medical Center of Chinese PLA General Hospital, Beijing, China.
- Key Laboratory for Regenerative Medicine of Ministry of Education, Institute of Hematology, School of Medicine, Jinan University, Guangzhou, China.
| | - Peng Liu
- Department of Spine Surgery, Center of Orthopedics, Daping Hospital, Army Medical University (Third Military Medical University), Chongqing, China.
- State Key Laboratory of Trauma, Burns and Combined Injury, Army Medical University (Third Military Medical University), Chongqing, China.
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13
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Spatially defined single-cell transcriptional profiling characterizes diverse chondrocyte subtypes and nucleus pulposus progenitors in human intervertebral discs. Bone Res 2021; 9:37. [PMID: 34400611 PMCID: PMC8368097 DOI: 10.1038/s41413-021-00163-z 10.1038/s41413-021-00163-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/09/2023] Open
Abstract
A comprehensive understanding of the cellular heterogeneity and molecular mechanisms underlying the development, homeostasis, and disease of human intervertebral disks (IVDs) remains challenging. Here, the transcriptomic landscape of 108 108 IVD cells was mapped using single-cell RNA sequencing of three main compartments from young and adult healthy IVDs, including the nucleus pulposus (NP), annulus fibrosus, and cartilage endplate (CEP). The chondrocyte subclusters were classified based on their potential regulatory, homeostatic, and effector functions in extracellular matrix (ECM) homeostasis. Notably, in the NP, a PROCR+ resident progenitor population showed enriched colony-forming unit-fibroblast (CFU-F) activity and trilineage differentiation capacity. Finally, intercellular crosstalk based on signaling network analysis uncovered that the PDGF and TGF-β cascades are important cues in the NP microenvironment. In conclusion, a single-cell transcriptomic atlas that resolves spatially regulated cellular heterogeneity together with the critical signaling that underlies homeostasis will help to establish new therapeutic strategies for IVD degeneration in the clinic.
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14
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Peredo AP, Gullbrand SE, Smith HE, Mauck RL. Putting the Pieces in Place: Mobilizing Cellular Players to Improve Annulus Fibrosus Repair. TISSUE ENGINEERING. PART B, REVIEWS 2021; 27:295-312. [PMID: 32907498 PMCID: PMC10799291 DOI: 10.1089/ten.teb.2020.0196] [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: 12/21/2022]
Abstract
The intervertebral disc (IVD) is an integral load-bearing tissue that derives its function from its composite structure and extracellular matrix composition. IVD herniations involve the failure of the annulus fibrosus (AF) and the extrusion of the nucleus pulposus beyond the disc boundary. Disc herniations can impinge the neural elements and cause debilitating pain and loss of function, posing a significant burden on individual patients and society as a whole. Patients with persistent symptoms may require surgery; however, surgical intervention fails to repair the ruptured AF and is associated with the risk for reherniation and further disc degeneration. Given the limitations of AF endogenous repair, many attempts have been made toward the development of effective repair approaches that reestablish IVD function. These methods, however, fail to recapitulate the composition and organization of the native AF, ultimately resulting in inferior tissue mechanics and function over time and high rates of reherniation. Harnessing the cellular function of cells (endogenous or exogenous) at the repair site through the provision of cell-instructive cues could enhance AF tissue regeneration and, ultimately, improve healing outcomes. In this study, we review the diverse approaches that have been developed for AF repair and emphasize the potential for mobilizing the appropriate cellular players at the site of injury to improve AF healing. Impact statement Conventional treatments for intervertebral disc herniation fail to repair the annulus fibrosus (AF), increasing the risk for recurrent herniation. The lack of repair devices in the market has spurred the development of regenerative approaches, yet most of these rely on a scarce endogenous cell population to repair large injuries, resulting in inadequate regeneration. This review identifies current and developing strategies for AF repair and highlights the potential for harnessing cellular function to improve AF regeneration. Ideal cell sources, differentiation strategies, and delivery methods are discussed to guide the design of repair systems that leverage specialized cells to achieve superior outcomes.
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Affiliation(s)
- Ana P. Peredo
- Department of Bioengineering, School of Engineering and Applied Sciences, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Translational Musculoskeletal Research Center, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, Pennsylvania, USA
| | - Sarah E. Gullbrand
- McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Translational Musculoskeletal Research Center, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, Pennsylvania, USA
| | - Harvey E. Smith
- McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Translational Musculoskeletal Research Center, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, Pennsylvania, USA
| | - Robert L. Mauck
- Department of Bioengineering, School of Engineering and Applied Sciences, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
- Translational Musculoskeletal Research Center, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, Pennsylvania, USA
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15
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McAlinden A, Hudson DM, Fernandes AA, Ravindran S, Fernandes RJ. Biochemical and immuno-histochemical localization of type IIA procollagen in annulus fibrosus of mature bovine intervertebral disc. Matrix Biol Plus 2021; 12:100077. [PMID: 34337380 PMCID: PMC8313739 DOI: 10.1016/j.mbplus.2021.100077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 06/08/2021] [Accepted: 06/24/2021] [Indexed: 11/05/2022] Open
Abstract
For next generation tissue-engineered constructs and regenerative medicine to succeed clinically, the basic biology and extracellular matrix composition of tissues that these repair techniques seek to restore have to be fully determined. Using the latest reagents coupled with tried and tested methodologies, we continue to uncover previously undetected structural proteins in mature intervertebral disc. In this study we show that the “embryonic” type IIA procollagen isoform (containing a cysteine-rich amino propeptide) was biochemically detectable in the annulus fibrosus of both calf and mature steer caudal intervertebral discs, but not in the nucleus pulposus where the type IIB isoform was predominantly localized. Specifically, the triple-helical type IIA procollagen isoform immunolocalized in the outer margins of the inner annulus fibrosus. Triple helical processed type II collagen exclusively localized within the inter-lamellae regions and with type IIA procollagen in the intra-lamellae regions. Mass spectrometry of the α1(II) collagen chains from the region where type IIA procollagen localized showed high 3-hydroxylation of Proline-944, a post-translational modification that is correlated with thin collagen fibrils as in the nucleus pulposus. The findings implicate small diameter fibrils of type IIA procollagen in select regions of the annulus fibrosus where it likely contributes to the organization of collagen bundles and structural properties within the type I-type II collagen transition zone.
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Affiliation(s)
- Audrey McAlinden
- Department of Orthopaedic Surgery, Washington University School of Medicine, St Louis, MO, USA.,Department of Cell Biology & Physiology, Washington University School of Medicine, St Louis, MO, USA.,Shriners Hospitals for Children- St Louis, MO, USA
| | - David M Hudson
- Department of Orthopaedic & Sports Medicine, University of Washington, Seattle, WA, USA
| | - Aysel A Fernandes
- Department of Orthopaedic & Sports Medicine, University of Washington, Seattle, WA, USA
| | - Soumya Ravindran
- Department of Orthopaedic Surgery, Washington University School of Medicine, St Louis, MO, USA
| | - Russell J Fernandes
- Department of Orthopaedic & Sports Medicine, University of Washington, Seattle, WA, USA
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16
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Stein D, Assaf Y, Dar G, Cohen H, Slon V, Kedar E, Medlej B, Abbas J, Hay O, Barazany D, Hershkovitz I. 3D virtual reconstruction and quantitative assessment of the human intervertebral disc's annulus fibrosus: a DTI tractography study. Sci Rep 2021; 11:6815. [PMID: 33767347 PMCID: PMC7994907 DOI: 10.1038/s41598-021-86334-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Accepted: 03/05/2021] [Indexed: 01/04/2023] Open
Abstract
The intervertebral disc’s (IVD) annulus fibrosus (AF) retains the hydrostatic pressure of the nucleus pulposus (NP), controls the range of motion, and maintains the integrity of the motion segment. The microstructure of the AF is not yet fully understood and quantitative characterization is lacking, leaving a caveat in modern medicine’s ability to prevent and treat disc failure (e.g., disc herniation). In this study, we show a reconstruction of the 3D microstructure of the fibers that constitute the AF via MRI diffusion tensor imaging (DTI) followed by fiber tracking. A quantitative analysis presents an anisotropic structure with significant architectural differences among the annuli along the width of the fibrous belt. These findings indicate that the outer annuli's construction reinforces the IVD while providing a sufficient degree of motion. Our findings also suggest an increased role of the outer annuli in IVD nourishment.
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Affiliation(s)
- Dan Stein
- Department of Anatomy and Anthropology, Sackler Faculty of Medicine, Tel Aviv University, 69978, Tel Aviv, Israel.,The Shmunis Family Anthropology Institute, Dan David Center for Human Evolution and Biohistory Research, Tel Aviv University, 69978, Tel Aviv, Israel
| | - Yaniv Assaf
- Department of Neurobiochemistry, Faculty of Life Sciences, Tel Aviv University, 69978, Tel Aviv, Israel
| | - Gali Dar
- Department of Physical Therapy, Faculty of Social Welfare and Health Studies, Haifa University, Mount Carmel, 31905, Haifa, Israel
| | - Haim Cohen
- Adelson School of Medicine, Ariel University, Kiryat Hamada 3, 40700, Ariel, Israel
| | - Viviane Slon
- Department of Anatomy and Anthropology, Sackler Faculty of Medicine, Tel Aviv University, 69978, Tel Aviv, Israel.,The Shmunis Family Anthropology Institute, Dan David Center for Human Evolution and Biohistory Research, Tel Aviv University, 69978, Tel Aviv, Israel
| | - Einat Kedar
- Department of Anatomy and Anthropology, Sackler Faculty of Medicine, Tel Aviv University, 69978, Tel Aviv, Israel.,The Shmunis Family Anthropology Institute, Dan David Center for Human Evolution and Biohistory Research, Tel Aviv University, 69978, Tel Aviv, Israel
| | - Bahaa Medlej
- Department of Anatomy and Anthropology, Sackler Faculty of Medicine, Tel Aviv University, 69978, Tel Aviv, Israel.,The Shmunis Family Anthropology Institute, Dan David Center for Human Evolution and Biohistory Research, Tel Aviv University, 69978, Tel Aviv, Israel
| | - Janan Abbas
- Department of Anatomy and Anthropology, Sackler Faculty of Medicine, Tel Aviv University, 69978, Tel Aviv, Israel
| | - Ori Hay
- Department of Anatomy and Anthropology, Sackler Faculty of Medicine, Tel Aviv University, 69978, Tel Aviv, Israel
| | - Daniel Barazany
- Department of Neurobiochemistry, Faculty of Life Sciences, Tel Aviv University, 69978, Tel Aviv, Israel
| | - Israel Hershkovitz
- Department of Anatomy and Anthropology, Sackler Faculty of Medicine, Tel Aviv University, 69978, Tel Aviv, Israel. .,The Shmunis Family Anthropology Institute, Dan David Center for Human Evolution and Biohistory Research, Tel Aviv University, 69978, Tel Aviv, Israel.
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17
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Peredo AP, Gullbrand SE, Mauck RL, Smith HE. A challenging playing field: Identifying the endogenous impediments to annulus fibrosus repair. JOR Spine 2021; 4:e1133. [PMID: 33778407 PMCID: PMC7984000 DOI: 10.1002/jsp2.1133] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 11/10/2020] [Accepted: 11/11/2020] [Indexed: 12/31/2022] Open
Abstract
Intervertebral disc (IVD) herniations, caused by annulus fibrosus (AF) tears that enable disc tissue extrusion beyond the disc space, are very prevalent, especially among adults in the third to fifth decade of life. Symptomatic herniations, in which the extruded tissue compresses surrounding nerves, are characterized by back pain, numbness, and tingling and can cause extreme physical disability. Patients whose symptoms persist after nonoperative intervention may undergo surgical removal of the herniated tissue via microdiscectomy surgery. The AF, however, which has a poor endogenous healing ability, is left unrepaired increasing the risk for re-herniation and pre-disposing the IVD to degenerative disc disease. The lack of understanding of the mechanisms involved in native AF repair limits the design of repair systems that overcome the impediments to successful AF restoration. Moreover, the complexity of the AF structure and the challenging anatomy of the repair environment represents a significant challenge for the design of new repair devices. While progress has been made towards the development of an effective AF repair technique, these methods have yet to demonstrate long-term repair and recovery of IVD biomechanics. In this review, the limitations of endogenous AF healing are discussed and key cellular events and factors involved are highlighted to identify potential therapeutic targets that can be integrated into AF repair methods. Clinical repair strategies and their limitations are described to further guide the design of repair approaches that effectively restore native tissue structure and function.
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Affiliation(s)
- Ana P. Peredo
- Department of BioengineeringSchool of Engineering and Applied Science, University of PennsylvaniaPhiladelphiaPennsylvaniaUSA
- McKay Orthopaedic Research Laboratory, Department of Orthopaedic SurgeryPerelman School of Medicine, University of PennsylvaniaPhiladelphiaPennsylvaniaUSA
- Translational Musculoskeletal Research CenterCorporal Michael J. Crescenz Veterans Affairs Medical CenterPhiladelphiaPennsylvaniaUSA
| | - Sarah E. Gullbrand
- McKay Orthopaedic Research Laboratory, Department of Orthopaedic SurgeryPerelman School of Medicine, University of PennsylvaniaPhiladelphiaPennsylvaniaUSA
- Translational Musculoskeletal Research CenterCorporal Michael J. Crescenz Veterans Affairs Medical CenterPhiladelphiaPennsylvaniaUSA
| | - Robert L. Mauck
- Department of BioengineeringSchool of Engineering and Applied Science, University of PennsylvaniaPhiladelphiaPennsylvaniaUSA
- McKay Orthopaedic Research Laboratory, Department of Orthopaedic SurgeryPerelman School of Medicine, University of PennsylvaniaPhiladelphiaPennsylvaniaUSA
- Translational Musculoskeletal Research CenterCorporal Michael J. Crescenz Veterans Affairs Medical CenterPhiladelphiaPennsylvaniaUSA
| | - Harvey E. Smith
- McKay Orthopaedic Research Laboratory, Department of Orthopaedic SurgeryPerelman School of Medicine, University of PennsylvaniaPhiladelphiaPennsylvaniaUSA
- Translational Musculoskeletal Research CenterCorporal Michael J. Crescenz Veterans Affairs Medical CenterPhiladelphiaPennsylvaniaUSA
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18
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Zhang XB, Hu YC, Cheng P, Zhou HY, Chen XY, Wu D, Zhang RH, Yu DC, Gao XD, Shi JT, Zhang K, Li SL, Song PJ, Wang KP. Targeted therapy for intervertebral disc degeneration: inhibiting apoptosis is a promising treatment strategy. Int J Med Sci 2021; 18:2799-2813. [PMID: 34220308 PMCID: PMC8241771 DOI: 10.7150/ijms.59171] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2021] [Accepted: 05/19/2021] [Indexed: 02/06/2023] Open
Abstract
Intervertebral disc (IVD) degeneration (IDD) is a multifactorial pathological process associated with low back pain (LBP). The pathogenesis is complicated, and the main pathological changes are IVD cell apoptosis and extracellular matrix (ECM) degradation. Apoptotic cell loss leads to ECM degradation, which plays an essential role in IDD pathogenesis. Apoptosis regulation may be a potential attractive therapeutic strategy for IDD. Previous studies have shown that IVD cell apoptosis is mainly induced by the death receptor pathway, mitochondrial pathway, and endoplasmic reticulum stress (ERS) pathway. This article mainly summarizes the factors that induce IDD and apoptosis, the relationship between the three apoptotic pathways and IDD, and potential therapeutic strategies. Preliminary animal and cell experiments show that targeting apoptotic pathway genes or drug inhibition can effectively inhibit IVD cell apoptosis and slow IDD progression. Targeted apoptotic pathway inhibition may be an effective strategy to alleviate IDD at the gene level. This manuscript provides new insights and ideas for IDD therapy.
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Affiliation(s)
- Xiao-Bo Zhang
- Department of Orthopedics, Lanzhou University Second Hospital, Lanzhou, Gansu 730000, PR China.,Department of Orthopedics, Honghui Hospital, Xi'an, Shanxi, 710000, PR China.,Key Laboratory of Bone and Joint Disease Research of Gansu Province, Lanzhou, Gansu 730000, PR China
| | - Yi-Cun Hu
- Department of Orthopedics, Lanzhou University Second Hospital, Lanzhou, Gansu 730000, PR China.,Key Laboratory of Bone and Joint Disease Research of Gansu Province, Lanzhou, Gansu 730000, PR China
| | - Peng Cheng
- Department of Orthopedics, Lanzhou University Second Hospital, Lanzhou, Gansu 730000, PR China.,Key Laboratory of Bone and Joint Disease Research of Gansu Province, Lanzhou, Gansu 730000, PR China
| | - Hai-Yu Zhou
- Department of Orthopedics, Lanzhou University Second Hospital, Lanzhou, Gansu 730000, PR China.,Xigu District People's Hospital, Lanzhou, Gansu 730000, PR China
| | - Xiang-Yi Chen
- Department of Orthopedics, Lanzhou University Second Hospital, Lanzhou, Gansu 730000, PR China.,Key Laboratory of Bone and Joint Disease Research of Gansu Province, Lanzhou, Gansu 730000, PR China
| | - Ding Wu
- Department of Orthopedics, Lanzhou University Second Hospital, Lanzhou, Gansu 730000, PR China.,Key Laboratory of Bone and Joint Disease Research of Gansu Province, Lanzhou, Gansu 730000, PR China
| | - Rui-Hao Zhang
- Department of Orthopedics, Lanzhou University Second Hospital, Lanzhou, Gansu 730000, PR China.,Key Laboratory of Bone and Joint Disease Research of Gansu Province, Lanzhou, Gansu 730000, PR China
| | - De-Chen Yu
- Department of Orthopedics, Lanzhou University Second Hospital, Lanzhou, Gansu 730000, PR China.,Key Laboratory of Bone and Joint Disease Research of Gansu Province, Lanzhou, Gansu 730000, PR China
| | - Xi-Dan Gao
- Department of Orthopedics, Lanzhou University Second Hospital, Lanzhou, Gansu 730000, PR China.,Key Laboratory of Bone and Joint Disease Research of Gansu Province, Lanzhou, Gansu 730000, PR China
| | - Jin-Tao Shi
- Department of Orthopedics, Lanzhou University Second Hospital, Lanzhou, Gansu 730000, PR China.,Key Laboratory of Bone and Joint Disease Research of Gansu Province, Lanzhou, Gansu 730000, PR China
| | - Kai Zhang
- Department of Orthopedics, Lanzhou University Second Hospital, Lanzhou, Gansu 730000, PR China.,Key Laboratory of Bone and Joint Disease Research of Gansu Province, Lanzhou, Gansu 730000, PR China
| | - Shao-Long Li
- Department of Orthopedics, Lanzhou University Second Hospital, Lanzhou, Gansu 730000, PR China.,Key Laboratory of Bone and Joint Disease Research of Gansu Province, Lanzhou, Gansu 730000, PR China
| | - Peng-Jie Song
- Department of Orthopedics, Lanzhou University Second Hospital, Lanzhou, Gansu 730000, PR China.,Key Laboratory of Bone and Joint Disease Research of Gansu Province, Lanzhou, Gansu 730000, PR China
| | - Ke-Ping Wang
- Department of Orthopedics, Lanzhou University Second Hospital, Lanzhou, Gansu 730000, PR China.,Xigu District People's Hospital, Lanzhou, Gansu 730000, PR China
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19
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Molladavoodi S, McMorran J, Gregory D. Mechanobiology of annulus fibrosus and nucleus pulposus cells in intervertebral discs. Cell Tissue Res 2019; 379:429-444. [PMID: 31844969 DOI: 10.1007/s00441-019-03136-1] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Accepted: 11/03/2019] [Indexed: 02/07/2023]
Abstract
Low back pain (LBP) is a chronic condition that can affect up to 80% of the global population. It is the number one cause of disability worldwide and has enormous socioeconomic consequences. One of the main causes of this condition is intervertebral disc (IVD) degeneration. IVD degenerative processes and inflammation associated with it has been the subject of many studies in both tissue and cell level. It is believed that the phenotype of the resident cells within the IVD directly affects homeostasis of the tissue. At the same time, IVDs located between vertebral bodies of spine are under various mechanical loading conditions in vivo. Therefore, investigating how mechanical loading can affect the behaviour of IVD cells has been a subject of many research articles. In this review paper, following a brief explanation of the anatomy of the IVD and its resident cells, we compiled mechanobiological studies of IVD cells (specifically, annulus fibrosus and nucleus pulposus cells) and synthesized and discussed the key findings of the field.
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Affiliation(s)
- Sara Molladavoodi
- Department of Kinesiology and Physical Education, Wilfrid Laurier University, Waterloo, ON, Canada.,Department of Health Sciences, Wilfrid Laurier University, Waterloo, ON, Canada
| | - John McMorran
- Department of Kinesiology and Physical Education, Wilfrid Laurier University, Waterloo, ON, Canada
| | - Diane Gregory
- Department of Kinesiology and Physical Education, Wilfrid Laurier University, Waterloo, ON, Canada. .,Department of Health Sciences, Wilfrid Laurier University, Waterloo, ON, Canada.
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20
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Herod TW, Veres SP. ISSLS PRIZE IN BASIC SCIENCE 2020: Beyond microstructure—circumferential specialization within the lumbar intervertebral disc annulus extends to collagen nanostructure, with counterintuitive relationships to macroscale material properties. EUROPEAN SPINE JOURNAL : OFFICIAL PUBLICATION OF THE EUROPEAN SPINE SOCIETY, THE EUROPEAN SPINAL DEFORMITY SOCIETY, AND THE EUROPEAN SECTION OF THE CERVICAL SPINE RESEARCH SOCIETY 2019; 29:670-685. [DOI: 10.1007/s00586-019-06223-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 10/11/2019] [Accepted: 11/15/2019] [Indexed: 02/07/2023]
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21
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Michalek AJ. A growth-based model for the prediction of fiber angle distribution in the intervertebral disc annulus fibrosus. Biomech Model Mechanobiol 2019; 18:1363-1369. [PMID: 30980210 DOI: 10.1007/s10237-019-01150-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Accepted: 04/08/2019] [Indexed: 10/27/2022]
Abstract
There is a growing interest in the development of patient-specific finite element models of the human lumbar spine for both the assessment of injury risk and the development of treatment strategies. A current challenge in implementing these models is that the outer annulus fibrosus of the disc is composed of concentric sheets of aligned collagen fibers, the helical angles of which vary spatially. In finite element models, fiber angle is typically assumed to be constant, based on average experimental measurements from a small number of locations. The present study hypothesized that the full spatial distribution of fiber angles in the annulus fibrosus may be predicted for any disc geometry by assuming growth from a thin cylinder with constant fiber angle. This hypothesis was tested by developing an analytical model of disc growth and calibrating it with fiber angle measurements of adult bovine caudal discs. The calibrated model was then run on a representative human lumbar disc geometry. The model was able to accurately predict fiber angle distributions in both the experimental bovine caudal disc measurements and literature-reported human lumbar disc measurements. Despite its theoretical basis in development, the model requires only mature state geometry, making it practical for implementation in patient-specific finite element analyses, in which disc geometry is obtained from clinical imaging.
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Affiliation(s)
- Arthur J Michalek
- Department of Mechanical and Aeronautical Engineering, Clarkson University, 8 Clarkson Ave, Box 5725, Potsdam, NY, 13699, USA.
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22
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Sharabi M, Levi-Sasson A, Wolfson R, Wade KR, Galbusera F, Benayahu D, Wilke HJ, Haj-Ali R. The Mechanical Role of the Radial Fiber Network Within the Annulus Fibrosus of the Lumbar Intervertebral Disc: A Finite Elements Study. J Biomech Eng 2018; 141:2709746. [DOI: 10.1115/1.4041769] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2018] [Indexed: 11/08/2022]
Abstract
The annulus fibrosus (AF) of the intervertebral disc (IVD) consists of a set of concentric layers composed of a primary circumferential collagen fibers arranged in an alternating oblique orientation. Moreover, there exists an additional secondary set of radial translamellar collagen fibers which connects the concentric layers, creating an interconnected fiber network. The aim of this study was to investigate the mechanical role of the radial fiber network. Toward that goal, a three-dimensional (3D) finite element model of the L3–L4 spinal segment was generated and calibrated to axial compression and pure moment loading. The AF model explicitly recognizes the two heterogeneous networks of fibers. The presence of radial fibers demonstrated a pronounced effect on the local disc responses under lateral bending, flexion, and extension modes. In these modes, the radial fibers were in a tensile state in the disc region that subjected to compression. In addition, the circumferential fibers, on the opposite side of the IVD, were also under tension. The local stress in the matrix was decreased in up to 9% in the radial fibers presence. This implies an active fiber network acting collectively to reduce the stresses and strains in the AF lamellae. Moreover, a reduction of 26.6% in the matrix sideways expansion was seen in the presence of the radial fibers near the neutral bending axis of the disc. The proposed biomechanical model provided a new insight into the mechanical role of the radial collagen fibers in the AF structure. This model can assist in the design of future IVD substitutes.
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Affiliation(s)
- Mirit Sharabi
- The Fleischman Faculty of Engineering, School of Mechanical Engineering, Tel Aviv University, Tel Aviv 69978, Israel
| | - Aviad Levi-Sasson
- The Fleischman Faculty of Engineering, School of Mechanical Engineering, Tel Aviv University, Tel Aviv 69978, Israel
| | - Roza Wolfson
- The Fleischman Faculty of Engineering, School of Mechanical Engineering, Tel Aviv University, Tel Aviv 69978, Israel
| | - Kelly R. Wade
- Institute of Orthopaedic Research and Biomechanics, University of Ulm, Ulm 89081, Germany
| | - Fabio Galbusera
- Institute of Orthopaedic Research and Biomechanics, University of Ulm, Ulm 89081, Germany
- IRCCS Galeazzi Orthopaedic Institute, Milan 20161, Italy
| | - Dafna Benayahu
- Department of Cell and Developmental Biology, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Hans-Joachim Wilke
- Institute of Orthopaedic Research and Biomechanics, University of Ulm, Ulm 89081, Germany
| | - Rami Haj-Ali
- Professor The Fleischman Faculty of Engineering, School of Mechanical Engineering, Tel Aviv University, Tel Aviv 69978, Israel e-mail:
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Torre OM, Mroz V, Bartelstein MK, Huang AH, Iatridis JC. Annulus fibrosus cell phenotypes in homeostasis and injury: implications for regenerative strategies. Ann N Y Acad Sci 2018; 1442:61-78. [PMID: 30604562 DOI: 10.1111/nyas.13964] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 08/05/2018] [Accepted: 08/15/2018] [Indexed: 12/11/2022]
Abstract
Despite considerable efforts to develop cellular, molecular, and structural repair strategies and restore intervertebral disk function after injury, the basic biology underlying intervertebral disk healing remains poorly understood. Remarkably, little is known about the origins of cell populations residing within the annulus fibrosus, or their phenotypes, heterogeneity, and roles during healing. This review focuses on recent literature highlighting the intrinsic and extrinsic cell types of the annulus fibrosus in the context of the injury and healing environment. Spatial, morphological, functional, and transcriptional signatures of annulus fibrosus cells are reviewed, including inner and outer annulus fibrosus cells, which we propose to be referred to as annulocytes. The annulus also contains peripheral cells, interlamellar cells, and potential resident stem/progenitor cells, as well as macrophages, T lymphocytes, and mast cells following injury. Phases of annulus fibrosus healing include inflammation and recruitment of immune cells, cell proliferation, granulation tissue formation, and matrix remodeling. However, annulus fibrosus healing commonly involves limited remodeling, with granulation tissues remaining, and the development of chronic inflammatory states. Identifying annulus fibrosus cell phenotypes during health, injury, and degeneration will inform reparative regeneration strategies aimed at improving annulus fibrosus healing.
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Affiliation(s)
- Olivia M Torre
- Leni and Peter W. May Department of Orthopaedics, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Victoria Mroz
- Leni and Peter W. May Department of Orthopaedics, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Meredith K Bartelstein
- Leni and Peter W. May Department of Orthopaedics, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Alice H Huang
- Leni and Peter W. May Department of Orthopaedics, Icahn School of Medicine at Mount Sinai, New York, New York
| | - James C Iatridis
- Leni and Peter W. May Department of Orthopaedics, Icahn School of Medicine at Mount Sinai, New York, New York
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Gullbrand SE, Kim DH, Bonnevie E, Ashinsky BG, Smith LJ, Elliott DM, Mauck RL, Smith HE. Towards the scale up of tissue engineered intervertebral discs for clinical application. Acta Biomater 2018; 70:154-164. [PMID: 29427744 PMCID: PMC7593900 DOI: 10.1016/j.actbio.2018.01.050] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 01/24/2018] [Accepted: 01/31/2018] [Indexed: 12/21/2022]
Abstract
Replacement of the intervertebral disc with a viable, tissue-engineered construct that mimics native tissue structure and function is an attractive alternative to fusion or mechanical arthroplasty for the treatment of disc pathology. While a number of engineered discs have been developed, the average size of these constructs remains a fraction of the size of human intervertebral discs. In this study, we fabricated medium (3 mm height × 10 mm diameter) and large (6 mm height × 20 mm diameter) sized disc-like angle ply structures (DAPS), encompassing size scales from the rabbit lumbar spine to the human cervical spine. Maturation of these engineered discs was evaluated over 15 weeks in culture by quantifying cell viability and metabolic activity, construct biochemical content, MRI T2 values, and mechanical properties. To assess the performance of the DAPS in the in vivo space, pre-cultured DAPS were implanted subcutaneously in athymic rats for 5 weeks. Our findings show that both sized DAPS matured functionally and compositionally during in vitro culture, as evidenced by increases in mechanical properties and biochemical content over time, yet large DAPS under-performed compared to medium DAPS. Subcutaneous implantation resulted in reductions in NP cell viability and GAG content at both size scales, with little effect on AF biochemistry or metabolic activity. These findings demonstrate that engineered discs at large size scales will mature during in vitro culture, however, future work will need to address the challenges of reduced cell viability and heterogeneous matrix distribution throughout the construct. STATEMENT OF SIGNIFICANCE This work establishes, for the first time, tissue-engineered intervertebral discs for total disc replacement at large, clinically relevant length scales. Clinical translation of tissue-engineered discs will offer an alternative to mechanical disc arthroplasty and fusion procedures, and may contribute to a paradigm shift in the clinical care for patients with disc pathology and associated axial spine and neurogenic extremity pain.
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Affiliation(s)
- Sarah E Gullbrand
- Translational Musculoskeletal Research Center, Corporal Michael J. Crescenz VA Medical Center, Philadelphia, PA, United States; McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA, United States
| | - Dong Hwa Kim
- Translational Musculoskeletal Research Center, Corporal Michael J. Crescenz VA Medical Center, Philadelphia, PA, United States; McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA, United States
| | - Edward Bonnevie
- Translational Musculoskeletal Research Center, Corporal Michael J. Crescenz VA Medical Center, Philadelphia, PA, United States; McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA, United States
| | - Beth G Ashinsky
- Translational Musculoskeletal Research Center, Corporal Michael J. Crescenz VA Medical Center, Philadelphia, PA, United States; McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA, United States; School of Biomedical Engineering, Drexel Univeristy, Philadelphia, PA, United States
| | - Lachlan J Smith
- Translational Musculoskeletal Research Center, Corporal Michael J. Crescenz VA Medical Center, Philadelphia, PA, United States; McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA, United States; Department of Neurosurgery, University of Pennsylvania, Philadelphia, PA, United States
| | - Dawn M Elliott
- Department of Biomedical Engineering, University of Delaware, Newark, DE, United States
| | - Robert L Mauck
- Translational Musculoskeletal Research Center, Corporal Michael J. Crescenz VA Medical Center, Philadelphia, PA, United States; McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA, United States; Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, United States
| | - Harvey E Smith
- Translational Musculoskeletal Research Center, Corporal Michael J. Crescenz VA Medical Center, Philadelphia, PA, United States; McKay Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA, United States.
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Abstract
STUDY DESIGN Microstructural investigation of low frequency cyclic loading and flexing of the lumbar disc. OBJECTIVE To explore micro-level structural damage in motion segments subjected to low frequency repetitive loading and flexing at sub-acute loads. SUMMARY OF BACKGROUND DATA Cumulative exposure to mechanical load has been implicated in low back pain and injury. The mechanical pathways by which cyclic loading physically affects spine tissues remain unclear, in part due to the absence of high quality microstructural evidence. METHODS The study utilized seven intact ovine lumbar spines and from each spine one motion segment was used as a control, two others were cyclically loaded. Ten motion segments were subjected to 5000 cycles at 0.5 Hz with a peak load corresponding to ∼30% of that required to achieve failure. An additional small group of segments subjected to 10,000 or 30,000 cycles was similarly analyzed. Following chemical fixation and decalcification samples were cryosectioned along one of the oblique fiber angles and imaged in their fully hydrated state using differential interference contrast optical microscopy. Structural damage obtained from the images was organized into an algebraic shell for analysis. RESULTS At 5000 cycles the disc damage was limited to inner wall distortions, evidence of stress concentrations at bridging-lamellae attachments, and small delaminations. The high-cycle discs tested exhibited significant mid-wall damage. There was no evidence of nuclear material being displaced. CONCLUSION At this low frequency and without the application of sustained loading or a more severe loading regime, or maintaining a constant flexion with repetitive loading, it seems unlikely that actual nuclear migration occurs. It is possible that the inner-annular damage shown in the low dose group could disrupt pathways for nutrient diffusion leading to earlier cell death and matrix degradation, thus contributing to a cascade of degeneration. LEVEL OF EVIDENCE N/A.
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Lawson LY, Harfe BD. Developmental mechanisms of intervertebral disc and vertebral column formation. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2017; 6. [DOI: 10.1002/wdev.283] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Revised: 05/09/2017] [Accepted: 05/23/2017] [Indexed: 01/01/2023]
Affiliation(s)
- Lisa Y. Lawson
- Department of Molecular Genetics and Microbiology; Genetics Institute University of Florida, College of Medicine; Gainesville FL USA
| | - Brian D. Harfe
- Department of Molecular Genetics and Microbiology; Genetics Institute University of Florida, College of Medicine; Gainesville FL USA
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Residual strains in the intervertebral disc annulus fibrosus suggest complex tissue remodeling in response to in-vivo loading. J Mech Behav Biomed Mater 2017; 68:232-238. [PMID: 28232297 DOI: 10.1016/j.jmbbm.2017.02.010] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Revised: 02/02/2017] [Accepted: 02/08/2017] [Indexed: 10/20/2022]
Abstract
The annulus fibrosus (AF) of the intervertebral disc (IVD) serves the dual roles of containing hydrostatic pressure from the inner nucleus pulposus (NP) and allowing flexible connection between adjacent vertebral bodies. Previous work has indicated that in the unloaded state, the AF is under a state of residual circumferential strain that, on average, is comparable to that which is believed to reduce peak stresses in other pressure containing organs. The complex in-vivo loading of the IVD, however, led us to hypothesize that variations with anatomical region should also exist. Residual strains were measured by imaging bovine caudal IVDs at both macro and micro scales in both the intact state (under residual strain) and opened into anterior, posterior, and lateral quadrants (residual strains relieved). Calculation of macro scale residual strains using changes in lamellar arc length and thickness confirmed circumferential tension (anterior: 0.63±2.1%, lateral: 8.3±1.5%, posterior: 4.4±2.1%) and radial compression (anterior: 12.4±5.8%, lateral: 11.120±2.8%, posterior: 4.8±4.2%) around the outer zone of the AF. The inner zone, however, had residual circumferential strains ranging from 28.7±3.4% compression in the anterior region to 3.4±3% tension in the posterior region, with radial strains of 9.7±5.5% tension and 0.2±4.4% compression respectively. This pattern of residual circumferential strain was corroborated at the microscale by comparing the crimp period of collagen fiber bundles in the intact and open states. The results of this study point toward a complex pattern of residual strains in the AF, which develop in response to stresses from both NP pressurization and bending movements.
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Tavakoli J, Elliott DM, Costi JJ. Structure and mechanical function of the inter-lamellar matrix of the annulus fibrosus in the disc. J Orthop Res 2016; 34:1307-15. [PMID: 27208689 DOI: 10.1002/jor.23306] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Accepted: 05/11/2016] [Indexed: 02/04/2023]
Abstract
The inter-lamellar matrix (ILM) has an average thickness of less than 30 µm and lies between adjacent lamellae in the annulus fibrosus (AF). The microstructure and composition of the ILM have been studied in various anatomic regions of the disc; however, their contribution to AF mechanical properties and structural integrity is unknown. It was suggested that the ILM components, mainly elastic fibers and cross-bridges, play a role in providing mechanical integrity of the AF. Therefore, the manner in which they respond to different loadings and stabilize adjacent lamellae structure will influence AF tear formation and subsequent herniation. This review paper summarizes the composition, microstructure, and potential role of the ILM in the progression of disc herniation, clarifies the micromechanical properties of the ILM, and proposes critical areas for future studies. There are a number of unknown characteristics of the ILM, such as its mechanical role, impact on AF integrity, and ultrastructure of elastic fibers at the ILM-lamella boundary. Determining these characteristics will provide important information for tissue engineering, repair strategies, and the development of more-physiological computational models to study the initiation and propagation of AF tears that lead to herniation and degeneration. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1307-1315, 2016.
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Affiliation(s)
- Javad Tavakoli
- Biomechanics and Implants Research Group, The Medical Device Research Institute, School of Computer Science, Engineering and Mathematics, Flinders University, GPO Box 2100, Adelaide 5042, South Australia, Australia
| | - Dawn M Elliott
- Department of Biomedical Engineering, University of Delaware, Newark, Delaware
| | - John J Costi
- Biomechanics and Implants Research Group, The Medical Device Research Institute, School of Computer Science, Engineering and Mathematics, Flinders University, GPO Box 2100, Adelaide 5042, South Australia, Australia
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Optical Coherence Tomographic Elastography Reveals Mesoscale Shear Strain Inhomogeneities in the Annulus Fibrosus. Spine (Phila Pa 1976) 2016; 41:E770-E777. [PMID: 26849796 PMCID: PMC4925193 DOI: 10.1097/brs.0000000000001463] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN Basic science study using in vitro tissue testing and imaging to characterize local strains in annulus fibrosus (AF) tissue. OBJECTIVE To characterize mesoscale strain inhomogeneities between lamellar and inter-/translamellar (ITL) matrix compartments during tissue shear loading. SUMMARY OF BACKGROUND DATA The intervertebral disc is characterized by significant heterogeneities in tissue structure and plays a critical role in load distribution and force transmission in the spine. In particular, the AF possesses a lamellar architecture interdigitated by a complex network of extracellular matrix components that form a distinct ITL compartment. Currently, there is not a firm understanding of how the lamellar and ITL matrix coordinately support tissue loading. METHODS AF tissue samples were prepared from frozen porcine lumbar spines and mounted onto custom fixtures of a materials testing system that incorporates optical coherence tomography (OCT) imaging to perform tissue elastography. Tissues were subjected to 20 and 40% nominal shear strain, and OCT images were captured and segmented to identify regions of interest corresponding to lamellar and ITL compartments. Images were analyzed using an optical flow algorithm to quantify local shear strains within each compartment. RESULTS Using histology and OCT, we first verified our ability to visualize and discriminate the ITL matrix from the lamellar matrix in porcine AF tissues. Local AF strains in the ITL compartment (22.0 ± 13.8, 31.1 ± 16.9 at 20% and 40% applied shear, respectively) were significantly higher than corresponding strains in the surrounding lamellar compartment (12.1 ± 5.6, 15.3 ± 5.2) for all tissue samples (P < 0.05). CONCLUSION Results from this study demonstrate that the lamellar and ITL compartments of the AF distribute strain unevenly during tissue loading. Specifically, shear strain is significantly higher in the ITL matrix, suggesting that these regions may be more susceptible to tissue damage and more mechanobiologically active. LEVEL OF EVIDENCE N/A.
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ISSLS Prize Winner: A Detailed Examination of the Elastic Network Leads to a New Understanding of Annulus Fibrosus Organization. Spine (Phila Pa 1976) 2015; 40:1149-57. [PMID: 25893352 DOI: 10.1097/brs.0000000000000943] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN Investigation of the elastic network in disc annulus and its function. OBJECTIVE To investigate the involvement of the elastic network in the structural interconnectivity of the annulus and to examine its possible mechanical role. SUMMARY OF BACKGROUND DATA The lamellae of the disc are now known to consist of bundles of collagen fibers organized into compartments. There is strong interconnectivity between adjacent compartments and between adjacent lamellae, possibly aided by a translamellar bridging network, containing blood vessels. An elastic network exists across the disc annulus and is particularly dense between the lamellae, and forms crossing bridges within the lamellae. METHODS Blocks of annulus taken from bovine caudal discs were studied in either their unloaded or radially stretched state then fixed and sectioned, and their structure analyzed optically using immunohistology. RESULTS An elastic network enclosed the collagen compartments, connecting the compartments with each other and with the elastic network of adjacent lamellae, formed an integrated network across the annulus, linking it together. Stretching experiments demonstrated the mechanical interconnectivities of the elastic fibers and the collagen compartments. CONCLUSION The annulus can be viewed as a modular structure organized into compartments of collagen bundles enclosed by an elastic sheath. The elastic network of these sheaths is interconnected mechanically across the entire annulus. This organization is also seen in the modular structure of tendon and muscle. The results provide a new understanding annulus structure and its interconnectivity, and contribute to fundamental structural information relevant to disc tissue engineering and mechanical modeling. LEVEL OF EVIDENCE N/A.
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Gorth DJ, Lothstein KE, Chiaro JA, Farrell MJ, Dodge GR, Elliott DM, Malhotra NR, Mauck RL, Smith LJ. Hypoxic regulation of functional extracellular matrix elaboration by nucleus pulposus cells in long-term agarose culture. J Orthop Res 2015; 33:747-54. [PMID: 25640328 PMCID: PMC4408762 DOI: 10.1002/jor.22821] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Accepted: 01/06/2015] [Indexed: 02/04/2023]
Abstract
Degeneration of the intervertebral discs is strongly implicated as a cause of low back pain. Since current treatments for discogenic low back pain show poor long-term efficacy, a number of new biological strategies are being pursued. For such therapies to succeed, it is critical that they be validated in conditions that mimic the unique biochemical microenvironment of the nucleus pulposus (NP), which include low oxygen tension. Therefore, the objective of this study was to investigate the effects of oxygen tension on NP cell functional extracellular matrix elaboration in 3D culture. Bovine NP cells were encapsulated in agarose constructs and cultured for 14 or 42 days in either 20% or 2% oxygen in defined media containing transforming growth factor beta-3. At each time point, extracellular matrix composition, biomechanics, and mRNA expression of key phenotypic markers were evaluated. Results showed that while bulk mechanics and composition were largely independent of oxygen level, low oxygen promoted improved restoration of the NP phenotype, higher mRNA expression of extracellular matrix and NP specific markers, and more uniform matrix elaboration. These findings indicate that culture under physiological oxygen levels is an important consideration for successful development of cell and growth factor-based regenerative strategies for the disc.
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Affiliation(s)
- Deborah J Gorth
- Department of Neurosurgery, University of Pennsylvania, Philadelphia, PA, USA
,Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA, USA
,Translational Musculoskeletal Research Center, Veterans Affairs Medical Center, Philadelphia, PA, USA
| | - Katherine E Lothstein
- Department of Neurosurgery, University of Pennsylvania, Philadelphia, PA, USA
,Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA, USA
,Translational Musculoskeletal Research Center, Veterans Affairs Medical Center, Philadelphia, PA, USA
| | - Joseph A Chiaro
- Department of Neurosurgery, University of Pennsylvania, Philadelphia, PA, USA
,Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA, USA
,Translational Musculoskeletal Research Center, Veterans Affairs Medical Center, Philadelphia, PA, USA
| | - Megan J Farrell
- Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA, USA
| | - George R Dodge
- Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA, USA
,Translational Musculoskeletal Research Center, Veterans Affairs Medical Center, Philadelphia, PA, USA
| | - Dawn M Elliott
- Department of Biomedical Engineering, University of Delaware, DE, USA
| | - Neil R Malhotra
- Department of Neurosurgery, University of Pennsylvania, Philadelphia, PA, USA
,Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA, USA
| | - Robert L Mauck
- Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA, USA
,Translational Musculoskeletal Research Center, Veterans Affairs Medical Center, Philadelphia, PA, USA
| | - Lachlan J Smith
- Department of Neurosurgery, University of Pennsylvania, Philadelphia, PA, USA
,Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA, USA
,Translational Musculoskeletal Research Center, Veterans Affairs Medical Center, Philadelphia, PA, USA
,Correspondence Department of Neurosurgery, University of Pennsylvania, 424 Stemmler Hall, 3450 Hamilton Walk, Philadelphia, PA, 19104, USA, Phone: 215 746 2169, Fax: 215 573 2133,
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Han SK, Chen CW, Wierwille J, Chen Y, Hsieh AH. Three dimensional mesoscale analysis of translamellar cross-bridge morphologies in the annulus fibrosus using optical coherence tomography. J Orthop Res 2015; 33:304-11. [PMID: 25564974 PMCID: PMC4346493 DOI: 10.1002/jor.22778] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Accepted: 10/26/2014] [Indexed: 02/04/2023]
Abstract
The defining characteristic of the annulus fibrosus (AF) of the intervertebral disc (IVD) has long been the lamellar structures that consist of highly ordered collagen fibers arranged in alternating oblique angles from one layer to the next. However, a series of recent histologic studies have demonstrated that AF lamellae contain elastin- and type VI collagen-rich secondary "cross-bridge" structures across lamellae. In this study, we use optical coherence tomography (OCT) to elucidate the three-dimensional (3-D) morphologies of these translamellar cross-bridges in AF tissues. Mesoscale volumetric images by OCT revealed a 3-D network of heterogeneously distributed cross-bridges. The results of this study confirm the translamellar cross-bridge is identifiable as a distinguishable structure, which lies in the interbundle space of adjacent lamellae and crisscrosses multiple lamellae in the radial direction. In contrast to previously proposed models extrapolated from 2-D sections, results from this current study show that translamellar cross-bridges exist as a complex, interconnected network. We also found much greater variation in lengths of cross-bridges within the interbundle space of lamellae (0.8-1.4 mm from the current study versus 0.3-0.6 mm from 2-D sections). OCT-based 3-D morphology of translamellar cross-bridge provides novel insight into the AF structure.
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Affiliation(s)
- Sang Kuy Han
- Fischell Department of Bioengineering, University of Maryland, College Park, MD, United States,Advanced Biomedical and Welfare Technology R&BD group, Korea Institute of Industrial Technology, Cheonan-si, Chungcheongnam-do, Korea
| | - Chao-Wei Chen
- Fischell Department of Bioengineering, University of Maryland, College Park, MD, United States
| | - Jerry Wierwille
- Fischell Department of Bioengineering, University of Maryland, College Park, MD, United States
| | - Yu Chen
- Fischell Department of Bioengineering, University of Maryland, College Park, MD, United States
| | - Adam H. Hsieh
- Fischell Department of Bioengineering, University of Maryland, College Park, MD, United States,Department of Orthopaedics, University of Maryland, Baltimore, MD, United States
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Demers S, Bouzid AH, Nadeau S. On the modeling of an intervertebral disc using a novel large deformation multi-shell approach. J Biomech Eng 2013; 135:51003. [PMID: 24231959 DOI: 10.1115/1.4024133] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2012] [Accepted: 04/04/2013] [Indexed: 11/08/2022]
Abstract
The objective of this study is to develop an analytical model to predict the stresses and displacements in the lamellae of the intervertebral disc subjected to a compressive force. This is achieved by developing a model based on membrane theory combined to large deformation multishell structural behavior. Equations for longitudinal and circumferential stresses are formulated for each lamella of the anulus fibrosus. Multilamellae interaction is a statically indeterminate problem, which requires equations of compatibility of the displacements of adjacent lamellae to be resolved. The large deformation inherent to soft tissue is considered and the solution is obtained using an iterative process. Elastic interactions with a large deformation is a novelty in analytical modeling of soft tissues. This provides model realism and offers the possibility for new and in-depth investigations. Results are given for longitudinal and circumferential stresses and displacements as well as contact pressures for every lamella of the anulus fibrosus. The analytical results are compared to those of two finite element models. The results suggest that the most highly stressed zone is located on the innermost lamella. Stresses decrease through disc thickness and are at a maximum at the innermost lamella. Circumferential stress is predominant and the difference is less than 5% at any point of the anulus fibrosus when the analytical model is compared to the finite element model using coupled degrees of freedom at the lamellae interface. When compared to the finite element model using contact elements, the difference is below 11%. Contact pressures from the inside to the outside of the anulus fibrosus are shown to decrease nonlinearly. The model presented in this study has demonstrated that it is possible to analytically simulate the complex mechanical behavior of a multishell intervertebral disc subjected to compression, provided some simplifications. Further improvements are suggested to increase model realism and recommendations are given for future experimentation necessary to support both the analytical and numerical models.
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Sun Z, Wan ZY, Guo YS, Wang HQ, Luo ZJ. FasL on human nucleus pulposus cells prevents angiogenesis in the disc by inducing Fas-mediated apoptosis of vascular endothelial cells. INTERNATIONAL JOURNAL OF CLINICAL AND EXPERIMENTAL PATHOLOGY 2013; 6:2376-2385. [PMID: 24228099 PMCID: PMC3816806] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Accepted: 09/30/2013] [Indexed: 06/02/2023]
Abstract
The intervertebral disc is the largest avascular organ in the human body. However, with the progress of intervertebral disc degeneration (IDD), the disc tends to be vascularized increasingly via angiogenesis. It is well established that both human nucleus pulposus (NP) cells and vascular endothelial cells express FasL and Fas. However, the issue remains open as to whether there are certain active mechanisms preventing angiogenesis in the disc via the FasL-Fas machinery. Here, we established a co-culture system of human NP cells and vascular endothelial (HMEC-1) cells. We found that normal NP cells were more capable of inducing apoptosis in HMEC-1 cells (14.2±3.4%) than degenerate NP cells (6.7±1.9%), p<0.05. By up-regulating the FasL expression in degenerate NP cells, we found that FasL played an essential role in the mediation of HMEC-1 cell apoptosis with the activation of downstream FADD and caspase-3. Furthermore, we found an increased Fas expression in HMEC-1 cells following co-cultured with NP cells, which might be closely linked with FasL produced by NP cells and enhance their interaction. Collectively, this is the first study showing FasL-Fas network might plays an important role in the molecular mechanisms of angiogenesis avoidance of human disc. Consequently, our findings might shed light on the pathogenesis in human IDD and provide a novel target for the treatment strategies for IDD.
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Affiliation(s)
- Zhen Sun
- Department of Orthopaedics, Xijing Hospital, Fourth Military Medical University Xi'an, China
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