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Peredo AP, Tsinman TK, Bonnevie ED, Jiang X, Smith HE, Gullbrand SE, Dyment NA, Mauck RL. Developmental morphogens direct human induced pluripotent stem cells toward an annulus fibrosus-like cell phenotype. JOR Spine 2024; 7:e1313. [PMID: 38283179 PMCID: PMC10810760 DOI: 10.1002/jsp2.1313] [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: 04/26/2023] [Revised: 12/08/2023] [Accepted: 12/11/2023] [Indexed: 01/30/2024] Open
Abstract
Introduction Therapeutic interventions for intervertebral disc herniation remain scarce due to the inability of endogenous annulus fibrosus (AF) cells to respond to injury and drive tissue regeneration. Unlike other orthopedic tissues, such as cartilage, delivery of exogenous cells to the site of annular injury remains underdeveloped, largely due to a lack of an ideal cell source and the invasive nature of cell isolation. Human induced pluripotent stem cells (iPSCs) can be differentiated to specific cell fates using biochemical factors and are, therefore, an invaluable tool for cell therapy approaches. While differentiation protocols have been developed for cartilage and fibrous connective tissues (e.g., tendon), the signals that regulate the induction and differentiation of human iPSCs toward the AF fate remain unknown. Methods iPSC-derived sclerotome cells were treated with various combinations of developmental signals including transforming growth factor beta 3 (TGF-β3), connective tissue growth factor (CTGF), platelet derived growth factor BB (PDGF-BB), insulin-like growth factor 1 (IGF-1), or the Hedgehog pathway activator, Purmorphamine, and gene expression changes in major AF-associated ECM genes were assessed. The top performing combination treatments were further validated by using three distinct iPSC lines and by assessing the production of upregulated ECM proteins of interest. To conduct a broader analysis of the transcriptomic shifts elicited by each factor combination, and to compare genetic profiles of treated cells to mature human AF cells, a 96.96 Fluidigm gene expression array was applied, and principal component analysis was employed to identify the transcriptional signatures of each cell population and treatment group in comparison to native AF cells. Results TGF-β3, in combination with PDGF-BB, CTGF, or IGF-1, induced an upregulation of key AF ECM genes in iPSC-derived sclerotome cells. In particular, treatment with a combination of TGF-β3 with PDGF-BB for 14 days significantly increased gene expression of collagen II and aggrecan and increased protein deposition of collagen I and elastin compared to other treatment groups. Assessment of genes uniquely highly expressed by AF cells or SCL cells, respectively, revealed a shift toward the genetic profile of AF cells with the addition of TGF-β3 and PDGF-BB for 14 days. Discussion These findings represent an initial approach to guide human induced pluripotent stem cells toward an AF-like fate for cellular delivery strategies.
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Affiliation(s)
- Ana P. Peredo
- Department of BioengineeringUniversity of PennsylvaniaPhiladelphiaPennsylvaniaUSA
- Department of Orthopaedic SurgeryUniversity of PennsylvaniaPhiladelphiaPennsylvaniaUSA
- Corporal Michael J. Crescenz VA Medical Center, Translational Musculoskeletal Research CenterPhiladelphiaPennsylvaniaUSA
| | - Tonia K. Tsinman
- Department of BioengineeringUniversity of PennsylvaniaPhiladelphiaPennsylvaniaUSA
- Department of Orthopaedic SurgeryUniversity of PennsylvaniaPhiladelphiaPennsylvaniaUSA
- Corporal Michael J. Crescenz VA Medical Center, Translational Musculoskeletal Research CenterPhiladelphiaPennsylvaniaUSA
| | - Edward D. Bonnevie
- Department of Orthopaedic SurgeryUniversity of PennsylvaniaPhiladelphiaPennsylvaniaUSA
- Corporal Michael J. Crescenz VA Medical Center, Translational Musculoskeletal Research CenterPhiladelphiaPennsylvaniaUSA
| | - Xi Jiang
- Department of Orthopaedic SurgeryUniversity of PennsylvaniaPhiladelphiaPennsylvaniaUSA
| | - Harvey E. Smith
- Department of Orthopaedic SurgeryUniversity of PennsylvaniaPhiladelphiaPennsylvaniaUSA
- Corporal Michael J. Crescenz VA Medical Center, Translational Musculoskeletal Research CenterPhiladelphiaPennsylvaniaUSA
| | - Sarah E. Gullbrand
- Department of Orthopaedic SurgeryUniversity of PennsylvaniaPhiladelphiaPennsylvaniaUSA
- Corporal Michael J. Crescenz VA Medical Center, Translational Musculoskeletal Research CenterPhiladelphiaPennsylvaniaUSA
| | - Nathaniel A. Dyment
- Department of BioengineeringUniversity of PennsylvaniaPhiladelphiaPennsylvaniaUSA
- Department of Orthopaedic SurgeryUniversity of PennsylvaniaPhiladelphiaPennsylvaniaUSA
| | - Robert L. Mauck
- Department of BioengineeringUniversity of PennsylvaniaPhiladelphiaPennsylvaniaUSA
- Department of Orthopaedic SurgeryUniversity of PennsylvaniaPhiladelphiaPennsylvaniaUSA
- Corporal Michael J. Crescenz VA Medical Center, Translational Musculoskeletal Research CenterPhiladelphiaPennsylvaniaUSA
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Zhou D, Liu H, Zheng Z, Wu D. Design principles in mechanically adaptable biomaterials for repairing annulus fibrosus rupture: A review. Bioact Mater 2024; 31:422-439. [PMID: 37692911 PMCID: PMC10485601 DOI: 10.1016/j.bioactmat.2023.08.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Revised: 07/25/2023] [Accepted: 08/12/2023] [Indexed: 09/12/2023] Open
Abstract
Annulus fibrosus (AF) plays a crucial role in the biomechanical loading of intervertebral disc (IVD). AF is difficult to self-heal when the annulus tears develop, because AF has a unique intricate structure and biologic milieu in vivo. Tissue engineering is promising for repairing AF rupture, but construction of suitable mechanical matching devices or scaffolds is still a grand challenge. To deeply know the varied forces involved in the movement of the native annulus is highly beneficial for designing biomimetic scaffolds to recreate the AF function. In this review, we overview six freedom degrees of forces and adhesion strength on AF tissue. Then, we summarize the mechanical modalities to simulate related forces on AF and to assess the characteristics of biomaterials. We finally outline some current advanced techniques to develop mechanically adaptable biomaterials for AF rupture repair.
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Affiliation(s)
- Dan Zhou
- Guangdong Provincial Key Laboratory of Advanced Biomaterials, Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Hongmei Liu
- Guangdong Provincial Key Laboratory of Advanced Biomaterials, Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen, 518055, China
| | - Zhaomin Zheng
- Department of Spine Surgery, The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, 510080, China
- Pain Research Center, Sun Yat-Sen University, Guangzhou 510080, China
| | - Decheng Wu
- Guangdong Provincial Key Laboratory of Advanced Biomaterials, Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen, 518055, China
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Vinestock RC, Felsenthal N, Assaraf E, Katz E, Rubin S, Heinemann-Yerushalmi L, Krief S, Dezorella N, Levin-Zaidman S, Tsoory M, Thomopoulos S, Zelzer E. Neonatal Enthesis Healing Involves Noninflammatory Acellular Scar Formation through Extracellular Matrix Secretion by Resident Cells. THE AMERICAN JOURNAL OF PATHOLOGY 2022; 192:1122-1135. [PMID: 35659946 PMCID: PMC9379688 DOI: 10.1016/j.ajpath.2022.05.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Revised: 04/19/2022] [Accepted: 05/04/2022] [Indexed: 06/15/2023]
Abstract
Wound healing typically recruits the immune and vascular systems to restore tissue structure and function. However, injuries to the enthesis, a hypocellular and avascular tissue, often result in fibrotic scar formation and loss of mechanical properties, severely affecting musculoskeletal function and life quality. This raises questions about the healing capabilities of the enthesis. Herein, this study established an injury model to the Achilles entheses of neonatal mice to study the effectiveness of early-age enthesis healing. Histology and immunohistochemistry analyses revealed an atypical process that did not involve inflammation or angiogenesis. Instead, healing was mediated by secretion of collagen types I and II by resident cells, which formed a permanent hypocellular and avascular scar. Transmission electron microscopy showed that the cellular response to injury, including endoplasmic reticulum stress, autophagy, and cell death, varied between the tendon and cartilage ends of the enthesis. Single-molecule in situ hybridization, immunostaining, and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling assays verified these differences. Finally, gait analysis showed that these processes effectively restored function of the injured leg. These findings reveal a novel healing mechanism in neonatal entheses, whereby local extracellular matrix secretion by resident cells forms an acellular extracellular matrix deposit without inflammation, allowing gait restoration. These insights into the healing mechanism of a complex transitional tissue may lead to new therapeutic strategies for adult enthesis injuries.
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Affiliation(s)
- Ron C Vinestock
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Neta Felsenthal
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Eran Assaraf
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Eldad Katz
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Sarah Rubin
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | | | - Sharon Krief
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Nili Dezorella
- Department of Electron Microscopy Unit, Weizmann Institute of Science, Rehovot, Israel
| | - Smadar Levin-Zaidman
- Department of Electron Microscopy Unit, Weizmann Institute of Science, Rehovot, Israel
| | - Michael Tsoory
- Department of Veterinary Resources, Weizmann Institute of Science, Rehovot, Israel
| | - Stavros Thomopoulos
- Department of Orthopedic Surgery, Columbia University, New York, New York; Department of Biomedical Engineering, Columbia University, New York, New York
| | - Elazar Zelzer
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel.
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Tang SN, Walter BA, Heimann MK, Gantt CC, Khan SN, Kokiko-Cochran ON, Askwith CC, Purmessur D. In vivo Mouse Intervertebral Disc Degeneration Models and Their Utility as Translational Models of Clinical Discogenic Back Pain: A Comparative Review. FRONTIERS IN PAIN RESEARCH 2022; 3:894651. [PMID: 35812017 PMCID: PMC9261914 DOI: 10.3389/fpain.2022.894651] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2022] [Accepted: 05/09/2022] [Indexed: 11/21/2022] Open
Abstract
Low back pain is a leading cause of disability worldwide and studies have demonstrated intervertebral disc (IVD) degeneration as a major risk factor. While many in vitro models have been developed and used to study IVD pathophysiology and therapeutic strategies, the etiology of IVD degeneration is a complex multifactorial process involving crosstalk of nearby tissues and systemic effects. Thus, the use of appropriate in vivo models is necessary to fully understand the associated molecular, structural, and functional changes and how they relate to pain. Mouse models have been widely adopted due to accessibility and ease of genetic manipulation compared to other animal models. Despite their small size, mice lumbar discs demonstrate significant similarities to the human IVD in terms of geometry, structure, and mechanical properties. While several different mouse models of IVD degeneration exist, greater standardization of the methods for inducing degeneration and the development of a consistent set of output measurements could allow mouse models to become a stronger tool for clinical translation. This article reviews current mouse models of IVD degeneration in the context of clinical translation and highlights a critical set of output measurements for studying disease pathology or screening regenerative therapies with an emphasis on pain phenotyping. First, we summarized and categorized these models into genetic, age-related, and mechanically induced. Then, the outcome parameters assessed in these models are compared including, molecular, cellular, functional/structural, and pain assessments for both evoked and spontaneous pain. These comparisons highlight a set of potential key parameters that can be used to validate the model and inform its utility to screen potential therapies for IVD degeneration and their translation to the human condition. As treatment of symptomatic pain is important, this review provides an emphasis on critical pain-like behavior assessments in mice and explores current behavioral assessments relevant to discogenic back pain. Overall, the specific research question was determined to be essential to identify the relevant model with histological staining, imaging, extracellular matrix composition, mechanics, and pain as critical parameters for assessing degeneration and regenerative strategies.
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Affiliation(s)
- Shirley N. Tang
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, United States
| | - Benjamin A. Walter
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, United States
- Department of Orthopaedics, Wexner Medical Center, The Ohio State University, Columbus, OH, United States
| | - Mary K. Heimann
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, United States
| | - Connor C. Gantt
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, United States
| | - Safdar N. Khan
- Department of Orthopaedics, Wexner Medical Center, The Ohio State University, Columbus, OH, United States
| | - Olga N. Kokiko-Cochran
- Department of Neuroscience, The Ohio State University, Columbus, OH, United States
- Institute for Behavioral Medicine Research, Neurological Institute, The Ohio State University, Columbus, OH, United States
| | - Candice C. Askwith
- Department of Neuroscience, The Ohio State University, Columbus, OH, United States
| | - Devina Purmessur
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH, United States
- Department of Orthopaedics, Wexner Medical Center, The Ohio State University, Columbus, OH, United States
- *Correspondence: Devina Purmessur ;
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Abstract
It is well established that humans and other mammals are minimally regenerative compared with organisms such as zebrafish, salamander or amphibians. In recent years, however, the identification of regenerative potential in neonatal mouse tissues that normally heal poorly in adults has transformed our understanding of regenerative capacity in mammals. In this Review, we survey the mammalian tissues for which regenerative or improved neonatal healing has been established, including the heart, cochlear hair cells, the brain and spinal cord, and dense connective tissues. We also highlight common and/or tissue-specific mechanisms of neonatal regeneration, which involve cells, signaling pathways, extracellular matrix, immune cells and other factors. The identification of such common features across neonatal tissues may direct therapeutic strategies that will be broadly applicable to multiple adult tissues.
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Affiliation(s)
| | - Alice H. Huang
- Department of Orthopedic Surgery, Columbia University, New York, NY 10032, USA
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DiStefano TJ, Vaso K, Danias G, Chionuma HN, Weiser JR, Iatridis JC. Extracellular Vesicles as an Emerging Treatment Option for Intervertebral Disc Degeneration: Therapeutic Potential, Translational Pathways, and Regulatory Considerations. Adv Healthc Mater 2022; 11:e2100596. [PMID: 34297485 PMCID: PMC8783929 DOI: 10.1002/adhm.202100596] [Citation(s) in RCA: 51] [Impact Index Per Article: 25.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 07/08/2021] [Indexed: 12/14/2022]
Abstract
Emergent approaches in regenerative medicine look toward the use of extracellular vesicles (EVs) as a next-generation treatment strategy for intervertebral disc (IVD) degeneration (IVDD) because of their ability to attenuate chronic inflammation, reduce apoptosis, and stimulate proliferation in a number of tissue systems. Yet, there are no Food and Drug Administration (FDA)-approved EV therapeutics in the market with an indication for IVDD, which motivates this article to review the current state of the field and provide an IVD-specific framework to assess its efficacy. In this systematic review, 29 preclinical studies that investigate EVs in relation to the IVD are identified, and additionally, the regulatory approval process is reviewed in an effort to accelerate emerging EV-based therapeutics toward FDA submission and timeline-to-market. The majority of studies focus on nucleus pulposus responses to EV treatment, where the main findings show that stem cell-derived EVs can decelerate the progression of IVDD on the molecular, cellular, and organ level. The findings also highlight the importance of the EV parent cell's pathophysiological and differentiation state, which affects downstream treatment responses and therapeutic outcomes. This systematic review substantiates the use of EVs as a promising cell-free strategy to treat IVDD and enhance endogenous repair.
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Affiliation(s)
- Tyler J. DiStefano
- Leni and Peter W. May Department of Orthopaedics, Icahn School of Medicine at Mount Sinai, New York NY, USA
| | - Keti Vaso
- Department of Chemical Engineering, The Cooper Union for the Advancement of Science and Art, New York NY, USA
| | - George Danias
- Leni and Peter W. May Department of Orthopaedics, Icahn School of Medicine at Mount Sinai, New York NY, USA
| | - Henry N. Chionuma
- Leni and Peter W. May Department of Orthopaedics, Icahn School of Medicine at Mount Sinai, New York NY, USA
| | - Jennifer R. Weiser
- Department of Chemical Engineering, The Cooper Union for the Advancement of Science and Art, New York NY, USA
| | - James C. Iatridis
- Leni and Peter W. May Department of Orthopaedics, Icahn School of Medicine at Mount Sinai, New York NY, USA
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7
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Di Pauli von Treuheim T, Torre OM, Ferreri ED, Nasser P, Abbondandolo A, Delgado Caceres M, Lin D, Docheva D, Iatridis JC. Tenomodulin and Chondromodulin-1 Are Both Required to Maintain Biomechanical Function and Prevent Intervertebral Disc Degeneration. Cartilage 2021; 13:604S-614S. [PMID: 34486420 PMCID: PMC8804743 DOI: 10.1177/19476035211029696] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
OBJECTIVE The underlying mechanisms and molecular factors influencing intervertebral disc (IVD) homeostasis and degeneration remain clinically relevant. Tenomodulin (Tnmd) and chondromodulin (Chm1) are antiangiogenic transmembrane glycoproteins, with cleavable C-terminus, expressed by IVD cells that are implicated in the onset of degenerative processes. We evaluate the organ-level biomechanical impact of knocking out Tnmd alone, and Tnmd and Chm1, simultaneously. DESIGN Caudal (c5-8) and lumbar vertebrae (L1-4) of skeletally mature male and female 9-month-old wildtype (WT), Tnmd knockout (Tnmd-/-), and Tnmd/Chm1 double knockout (Tnmd-/-/Chm-/-) mice were used (n = 9-13 per group). Disc height index (DHI), histomorphological changes, and axial, torsional, creep, and failure biomechanical properties were evaluated. Differences were assessed by one-way ANOVA with post hoc Bonferroni-corrected comparisons (P < 0.05). RESULTS Tnmd-/-/Chm1-/- IVDs displayed increased DHI and histomorphological scores that indicated increased IVD degeneration compared to the WT and Tnmd-/- groups. Double knockout IVDs required significantly less torque and energy to initiate torsional failure. Creep parameters were comparable between all groups, except for the slow time constant, which indicated faster outward fluid flow. Tnmd-/- IVDs lost fluid faster than the WT group, and this effect was amplified in the double knockout IVDs. CONCLUSION Knocking out Tnmd and Chm1 affects IVD fluid flow and organ-level biomechanical function and therefore may play a role in contributing to IVD degeneration. Larger effects of the Tnmd and Chm1 double knockout mice compared to the Tnmd single mutant suggest that Chm1 may play a compensatory role in the Tnmd single mutant IVDs.
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Affiliation(s)
| | - Olivia M. Torre
- Leni & Peter W. May Department of
Orthopaedics, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Emily D. Ferreri
- Leni & Peter W. May Department of
Orthopaedics, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Philip Nasser
- Leni & Peter W. May Department of
Orthopaedics, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Angelica Abbondandolo
- Leni & Peter W. May Department of
Orthopaedics, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Manuel Delgado Caceres
- Experimental Trauma Surgery, Department
of Trauma Surgery, University Regensburg Medical Centre, Regensburg, Germany
| | - Dasheng Lin
- Orthopaedic Center of People’s
Liberation Army, The Affiliated Southeast Hospital of Xiamen University, Zhangzhou,
China
| | - Denitsa Docheva
- Experimental Trauma Surgery, Department
of Trauma Surgery, University Regensburg Medical Centre, Regensburg, Germany
| | - James C. Iatridis
- Leni & Peter W. May Department of
Orthopaedics, Icahn School of Medicine at Mount Sinai, New York, NY, USA,James C. Iatridis, Leni & Peter W. May
Department of Orthopaedics, Icahn School of Medicine at Mount Sinai, One Gustave
Levy Place, Box 1188, New York, NY 10029-6574, USA.
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8
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Ayala S, Delco ML, Fortier LA, Cohen I, Bonassar LJ. Cartilage articulation exacerbates chondrocyte damage and death after impact injury. J Orthop Res 2021; 39:2130-2140. [PMID: 33274781 PMCID: PMC8175450 DOI: 10.1002/jor.24936] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 09/21/2020] [Accepted: 12/01/2020] [Indexed: 02/04/2023]
Abstract
Posttraumatic osteoarthritis (PTOA) is typically initiated by momentary supraphysiologic shear and compressive forces delivered to articular cartilage during acute joint injury and develops through subsequent degradation of cartilage matrix components and tissue remodeling. PTOA affects 12% of the population who experience osteoarthritis and is attributed to over $3 billion dollars annually in healthcare costs. It is currently unknown whether articulation of the joint post-injury helps tissue healing or exacerbates cellular dysfunction and eventual death. We hypothesize that post-injury cartilage articulation will lead to increased cartilage damage. Our objective was to test this hypothesis by mimicking the mechanical environment of the joint during and post-injury and determining if subsequent joint articulation exacerbates damage produced by initial injury. We use a model of PTOA that combines impact injury and repetitive sliding with confocal microscopy to quantify and track chondrocyte viability, apoptosis, and mitochondrial depolarization in a depth-dependent manner. Cartilage explants were harvested from neonatal bovine knee joints and subjected to either rapid impact injury (17.34 ± 0.99 MPa, 21.6 ± 2.45 GPa/s), sliding (60 min at 1 mm/s, under 15% axial compression), or rapid impact injury followed by sliding. Explants were then bisected and fluorescently stained for cell viability, caspase activity (apoptosis), and mitochondria polarization. Results show that compared to either impact or sliding alone, explants that were both impacted and slid experienced higher magnitudes of damage spanning greater tissue depths.
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Affiliation(s)
- Steven Ayala
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY
| | - Michelle L. Delco
- Department of Clinical Sciences, Cornell University College of Veterinary Medicine, Ithaca, NY
| | - Lisa A. Fortier
- Department of Clinical Sciences, Cornell University College of Veterinary Medicine, Ithaca, NY
| | - Itai Cohen
- Department of Physics, Cornell University, Ithaca, NY
| | - Lawrence J. Bonassar
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY,Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, NY,Address Correspondence to: Lawrence J. Bonassar, PhD., Professor, Department of Biomedical Engineering, 149 Weill Hall, Cornell University, Ithaca, NY 14853, (607) 255-9381,
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9
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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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10
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Kaji DA, Montero AM, Patel R, Huang AH. Transcriptional profiling of mESC-derived tendon and fibrocartilage cell fate switch. Nat Commun 2021; 12:4208. [PMID: 34244516 PMCID: PMC8270956 DOI: 10.1038/s41467-021-24535-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2020] [Accepted: 06/24/2021] [Indexed: 12/13/2022] Open
Abstract
The transcriptional regulators underlying induction and differentiation of dense connective tissues such as tendon and related fibrocartilaginous tissues (meniscus and annulus fibrosus) remain largely unknown. Using an iterative approach informed by developmental cues and single cell RNA sequencing (scRNA-seq), we establish directed differentiation models to generate tendon and fibrocartilage cells from mouse embryonic stem cells (mESCs) by activation of TGFβ and hedgehog pathways, achieving 90% induction efficiency. Transcriptional signatures of the mESC-derived cells recapitulate embryonic tendon and fibrocartilage signatures from the mouse tail. scRNA-seq further identify retinoic acid signaling as a critical regulator of cell fate switch between TGFβ-induced tendon and fibrocartilage lineages. Trajectory analysis by RNA sequencing define transcriptional modules underlying tendon and fibrocartilage fate induction and identify molecules associated with lineage-specific differentiation. Finally, we successfully generate 3-dimensional engineered tissues using these differentiation protocols and show activation of mechanotransduction markers with dynamic tensile loading. These findings provide a serum-free approach to generate tendon and fibrocartilage cells and tissues at high efficiency for modeling development and disease.
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Affiliation(s)
- Deepak A Kaji
- Department of Orthopaedics, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Angela M Montero
- Department of Orthopaedics, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Roosheel Patel
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Alice H Huang
- Department of Orthopaedics, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
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11
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Li X, Yang S, Qin L, Yang S. Type II collagen-positive embryonic progenitors are the major contributors to spine and intervertebral disc development and repair. Stem Cells Transl Med 2021; 10:1419-1432. [PMID: 34032373 PMCID: PMC8459639 DOI: 10.1002/sctm.20-0424] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2020] [Revised: 01/23/2021] [Accepted: 02/16/2021] [Indexed: 12/23/2022] Open
Abstract
Type II collagen-positive embryonic progenitors are the major contributors to spine and intervertebral disc development and repair has been removed because it was published by mistake. The article will be published on October 1, 2021.
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Affiliation(s)
- Xinhua Li
- Department of Basic and Translational Sciences, School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Department of Orthopedics, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, People's Republic of China.,Department of Spinal Surgery, East Hospital, Tongji University, School of Medicine, Shanghai, People's Republic of China
| | - Shuting Yang
- Department of Basic and Translational Sciences, School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Ling Qin
- Department of Orthopedic Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Shuying Yang
- Department of Basic and Translational Sciences, School of Dental Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.,The Penn Center for Musculoskeletal Disorders, School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Center for Innovation & Precision Dentistry, School of Dental Medicine, School of Engineering and Applied Sciences, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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12
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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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13
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DiStefano TJ, Shmukler JO, Danias G, Iatridis JC. The Functional Role of Interface Tissue Engineering in Annulus Fibrosus Repair: Bridging Mechanisms of Hydrogel Integration with Regenerative Outcomes. ACS Biomater Sci Eng 2020; 6:6556-6586. [PMID: 33320618 PMCID: PMC7809646 DOI: 10.1021/acsbiomaterials.0c01320] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Hydrogels are extraordinarily versatile by design and can enhance repair in diseased and injured musculoskeletal tissues. Biological fixation of these constructs is a significant determinant factor that is critical to the clinical success and functionality of regenerative technologies for musculoskeletal repair. In the context of an intervertebral disc (IVD) herniation, nucleus pulposus tissue protrudes through the ruptured annulus fibrosus (AF), consequentially impinging on spinal nerve roots and causing debilitating pain. Discectomy is the surgical standard of care to treat symptomatic herniation; however these procedures do not repair AF defects, and these lesions are a significant risk factor for recurrent herniation. Advances in tissue engineering utilize adhesive hydrogels as AF sealants; however these repair strategies have yet to progress beyond preclinical animal models because these biomaterials are often plagued by poor integration with AF tissue and lead to large variability in repair outcomes. These critical barriers to translation motivate this article to review the material composition of hydrogels that have been evaluated in situ for AF repair, proposed mechanisms of how these biomaterials interface with AF tissue, and their functional outcomes after treatment in order to inform the development of new hydrogels for AF repair. In this systematic review, we identify 18 hydrogel formulations evaluated for AF repair, all of which demonstrate large heterogeneity in their interfacing mechanisms and reported outcome measures to assess the effectiveness of repair. Hydrogels that covalently bond to AF tissue were found to be the most successful in improving IVD biomechanical properties from the injured state, but none were able to restore properties to the intact state suggesting that new repair strategies with innovative surface chemistries are an important future direction. We additionally review biomechanical evaluation methods and recommend standardization in the field of AF tissue engineering to establish mechanical benchmarks for translation and ensure clinical feasibility.
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Affiliation(s)
- Tyler J DiStefano
- Leni and Peter W. May Department of Orthopaedics, Icahn School of Medicine at Mount Sinai, New York, New York 10029, United States
| | - Jennifer O Shmukler
- Leni and Peter W. May Department of Orthopaedics, Icahn School of Medicine at Mount Sinai, New York, New York 10029, United States
| | - George Danias
- Leni and Peter W. May Department of Orthopaedics, Icahn School of Medicine at Mount Sinai, New York, New York 10029, United States
| | - James C Iatridis
- Leni and Peter W. May Department of Orthopaedics, Icahn School of Medicine at Mount Sinai, New York, New York 10029, United States
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14
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Hoy RC, D'Erminio DN, Krishnamoorthy D, Natelson DM, Laudier DM, Illien‐Jünger S, Iatridis JC. Advanced glycation end products cause RAGE-dependent annulus fibrosus collagen disruption and loss identified using in situ second harmonic generation imaging in mice intervertebral disk in vivo and in organ culture models. JOR Spine 2020; 3:e1126. [PMID: 33392460 PMCID: PMC7770195 DOI: 10.1002/jsp2.1126] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Revised: 08/12/2020] [Accepted: 09/09/2020] [Indexed: 12/13/2022] Open
Abstract
Aging and diabetes are associated with increased low-back pain and intervertebral disk (IVD) degeneration yet causal mechanisms remain uncertain. Advanced glycation end products (AGEs), which accumulate in IVDs from aging and are implicated in diabetes-related disorders, alter collagen and induce proinflammatory conditions. A need exists for methods that assess IVD collagen quality and degradation in order to better characterize specific structural changes in IVDs due to AGE accumulation and to identify roles for the receptor for AGEs (RAGE). We used multiphoton microscopy with second harmonic generation (SHG), collagen-hybridizing peptide (CHP), and image analysis methods to characterize effects of AGEs and RAGE on collagen quality and quantity in IVD annulus fibrosus (AF). First, we used SHG imaging on thin sections with an in vivo dietary mouse model and determined that high-AGE (H-AGE) diets increased AF fibril disruption and collagen degradation resulting in decreased total collagen content, suggesting an early degenerative cascade. Next, we used in situ SHG imaging with an ex vivo IVD organ culture model of AGE challenge on wild type and RAGE-knockout (RAGE-KO) mice and determined that early degenerative changes to collagen quality and degradation were RAGE dependent. We conclude that AGE accumulation leads to RAGE-dependent collagen disruption in the AF and can initiate molecular and tissue level collagen disruption. Furthermore, SHG and CHP analyzes were sensitive to collagenous alterations at multiple hierarchical levels due to AGE and may be useful in identifying additional contributors to collagen damage in IVD degeneration processes.
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Affiliation(s)
- Robert C. Hoy
- Leni & Peter W. May Department of OrthopaedicsIcahn School of Medicine at Mount SinaiNYUnited StatesUSA
| | - Danielle N. D'Erminio
- Leni & Peter W. May Department of OrthopaedicsIcahn School of Medicine at Mount SinaiNYUnited StatesUSA
| | - Divya Krishnamoorthy
- Leni & Peter W. May Department of OrthopaedicsIcahn School of Medicine at Mount SinaiNYUnited StatesUSA
| | - Devorah M. Natelson
- Leni & Peter W. May Department of OrthopaedicsIcahn School of Medicine at Mount SinaiNYUnited StatesUSA
| | - Damien M. Laudier
- Leni & Peter W. May Department of OrthopaedicsIcahn School of Medicine at Mount SinaiNYUnited StatesUSA
| | | | - James C. Iatridis
- Leni & Peter W. May Department of OrthopaedicsIcahn School of Medicine at Mount SinaiNYUnited StatesUSA
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15
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Tessier S, Risbud MV. Understanding embryonic development for cell-based therapies of intervertebral disc degeneration: Toward an effort to treat disc degeneration subphenotypes. Dev Dyn 2020; 250:302-317. [PMID: 32564440 DOI: 10.1002/dvdy.217] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 06/09/2020] [Accepted: 06/14/2020] [Indexed: 12/19/2022] Open
Abstract
Chronic low back and neck pain are associated with intervertebral disc degeneration and are major contributors to the global burden of disability. New evidence now suggests that disc degeneration comprises a spectrum of subphenotypes influenced by genetic background, age, and environmental factors, which may be contributing to the mixed outcomes seen in clinical trials of cell-based therapies that aim to treat disc degeneration. This problem is further compounded by the fact that disc degeneration and aging coincide with an exhaustion of endogenous progenitor cells, imposing limitations on the regenerative capacity of the disc. At the bench-side, current work is focused on applying our knowledge of embryonic disc development to direct and refine differentiation of adult and human-induced pluripotent stem cells into notochord-like and nucleus pulposus-like cells for use in novel cell-based therapies. Accordingly, this review presents the salient features of intervertebral disc development, post-natal maintenance, and regeneration, with emphasis on recent advancements. We also discuss how a stratified approach can be undertaken for the development of future cell-based therapies to bring emerging subphenotypes into consideration.
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Affiliation(s)
- Steven Tessier
- Lewis Katz School of Medicine, Temple University, Philadelphia, Pennsylvania, USA.,Department of Orthopaedic Surgery, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Makarand V Risbud
- Department of Orthopaedic Surgery, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania, USA.,Graduate Program in Cell Biology and Regenerative Medicine, Jefferson College of Life Sciences, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
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16
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Natelson DM, Lai A, Krishnamoorthy D, Hoy RC, Iatridis JC, Illien-Jünger S. Leptin signaling and the intervertebral disc: Sex dependent effects of leptin receptor deficiency and Western diet on the spine in a type 2 diabetes mouse model. PLoS One 2020; 15:e0227527. [PMID: 32374776 PMCID: PMC7202633 DOI: 10.1371/journal.pone.0227527] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 04/14/2020] [Indexed: 12/14/2022] Open
Abstract
Type 2 diabetes and obesity are associated with back pain in juveniles and adults and are implicated in intervertebral disc (IVD) degeneration. Hypercaloric Western diets are associated with both obesity and type 2 diabetes. The objective of this study was to determine if obesity and type 2 diabetes result in spinal pathology in a sex-specific manner using in vivo diabetic and dietary mouse models. Leptin is an appetite-regulating hormone, and its deficiency leads to polyphagia, resulting in obesity and diabetes. Leptin is also associated with IVD degeneration, and increased expression of its receptor was identified in degenerated IVDs. We used young, leptin receptor deficient (Db/Db) mice to mimic the effect of diet and diabetes on adolescents. Db/Db and Control mice were fed either Western or Control diets, and were sacrificed at 3 months of age. Db/Db mice were obese, while only female mice developed diabetes. Female Db/Db mice displayed altered IVD morphology, with increased intradiscal notochordal band area, suggesting delayed IVD cell proliferation and differentiation, rather than IVD degeneration. Motion segments from Db/Db mice exhibited increased failure risk with decreased torsional failure strength. Db/Db mice also had inferior bone quality, which was most prominent in females. We conclude that obesity and diabetes due to impaired leptin signaling contribute to pathological changes in vertebrae, as well as an immature IVD phenotype, particularly of females, suggesting a sex-dependent role of leptin in the spine.
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Affiliation(s)
- Devorah M. Natelson
- Department of Orthopaedics, Icahn School of Medicine at Mount Sinai, New York, NY, United States of America
| | - Alon Lai
- Department of Orthopaedics, Icahn School of Medicine at Mount Sinai, New York, NY, United States of America
| | - Divya Krishnamoorthy
- Department of Orthopaedics, Icahn School of Medicine at Mount Sinai, New York, NY, United States of America
| | - Robert C. Hoy
- Department of Orthopaedics, Icahn School of Medicine at Mount Sinai, New York, NY, United States of America
| | - James C. Iatridis
- Department of Orthopaedics, Icahn School of Medicine at Mount Sinai, New York, NY, United States of America
| | - Svenja Illien-Jünger
- Department of Orthopaedics, Icahn School of Medicine at Mount Sinai, New York, NY, United States of America
- Department of Orthopaedics, Emory University School of Medicine, Atlanta, GA, United States of America
- * E-mail:
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17
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Li X, Yang S, Han L, Mao K, Yang S. Ciliary IFT80 is essential for intervertebral disc development and maintenance. FASEB J 2020; 34:6741-6756. [PMID: 32227389 DOI: 10.1096/fj.201902838r] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Revised: 02/19/2020] [Accepted: 03/14/2020] [Indexed: 12/24/2022]
Abstract
The intervertebral disc degeneration (IVDD)-related diseases occur in more than 90% of the population older than 50 years. Owing to the lack of understanding of the cellular mechanisms involved in IVDD formation effective treatment options are still unavailable. Primary cilia are microtubule-based organelles that play important roles in the organ development. Intraflagellar transport (IFT) proteins are essential for the assembly and bidirectional transport within the cilium. Role of cilia and IFT80 protein in intervertebral disc (IVD) development, maintenance, and degeneration are largely unknown. Using cilia-GFP mice, we found presence of cilia on growth plate (GP), cartilage endplate (EP) annulus fibrosus (AF), and nucleus pulposus (NP) with varying ciliary length. Cilia length in NP and AF during IVDD were significantly decreased. However, cilia numbers increased by 63% in AF during repair. Deletion of IFT80 in type II collagen-positive cells resulted in cilia loss in GP and EP, and disrupted IVD structure with disorganized and decreased GP, EP, and internal AF (IAF), and less compact and markedly decreased gel-like matrix in the NP. Deletion of IFT80 in type I collagen-positive cells led to a disorganized outer AF (OAF) with thinner, loosened, and disconnected fiber alignment. Mechanistic analyses showed that loss of IFT80 caused a significant increase in cell apoptosis in the IVD, and a marked decrease in expression of chondrogenic markers - type II collagen, sox9, aggrecan, and hedgehog (Hh) signaling components, including Gli1 and Patch1 in the IVD of IFT80fl/fl ; Col2-creERT mice, and Gli1 and Patch1 expression in the OAF of IFT80fl/fl ; Col1-creERT mice. Interestingly, Smoothened agonist-SAG rescued OAF cell proliferation and osteogenic differentiation. Our findings demonstrate that ciliary IFT80 is important for the maintenance of IVD cell organization and function through regulating the cell survival and Hh signaling.
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Affiliation(s)
- Xinhua Li
- Department of Basic and Translational Science, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, USA.,Department of Spinal Surgery, East Hospital, Tongji University, School of Medicine, Shanghai, China
| | - Shuting Yang
- Department of Basic and Translational Science, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Lin Han
- School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, PA, USA
| | - Keya Mao
- Department of Orthopedics, Chinese PLA General Hospital (301 Hospital), Beijing, China
| | - Shuying Yang
- Department of Basic and Translational Science, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, USA.,The Penn Center for Musculoskeletal Disorders, School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.,Center for Innovation & Precision Dentistry, School of Dental Medicine, School of Engineering and Applied Sciences, University of Pennsylvania, Philadelphia, PA, USA
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18
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Du J, Long R, Nakai T, Sakai D, Benneker L, Zhou G, Li B, Eglin D, Iatridis J, Alini M, Grad S, Li Z. Functional cell phenotype induction with TGF-β1 and collagen-polyurethane scaffold for annulus fibrosus rupture repair. Eur Cell Mater 2020; 39:1-17. [PMID: 31899537 PMCID: PMC7027376 DOI: 10.22203/ecm.v039a01] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Appropriate cell sources, bioactive factors and biomaterials for generation of functional and integrated annulus fibrosus (AF) tissue analogues are still an unmet need. In the present study, the AF cell markers, collagen type I, cluster of differentiation 146 (CD146), mohawk (MKX) and smooth muscle protein 22α (SM22α) were found to be suitable indicators of functional AF cell induction. In vitro 2D culture of human AF cells showed that transforming growth factor β1 (TGF-β1) upregulated the expression of the functional AF markers and increased cell contractility, indicating that TGF-β1-pre-treated AF cells were an appropriate cell source for AF tissue regeneration. Furthermore, a tissue engineered construct, composed of polyurethane (PU) scaffold with a TGF-β1-supplemented collagen type I hydrogel and human AF cells, was evaluated with in vitro 3D culture and ex vivo preclinical bioreactor-loaded organ culture models. The collagen type I hydrogel helped maintaining the AF functional phenotype. TGF-β1 supplement within the collagen I hydrogel further promoted cell proliferation and matrix production of AF cells within in vitro 3D culture. In the ex vivo IVD organ culture model with physiologically relevant mechanical loading, TGF-β1 supplement in the transplanted constructs induced the functional AF cell phenotype and enhanced collagen matrix synthesis. In conclusion, TGF-β1-containing collagen-PU constructs can induce the functional cell phenotype of human AF cells in vitro and in situ. This combined cellular, biomaterial and bioactive agent therapy has a great potential for AF tissue regeneration and rupture repair.
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Affiliation(s)
- J. Du
- AO Research Institute Davos, Davos, Switzerland
| | - R.G. Long
- AO Research Institute Davos, Davos, Switzerland,Icahn School of Medicine at Mount Sinai, New York, USA,Collaborative Research Program Annulus Fibrosus Repair, AO Foundation, Davos, Switzerland
| | - T. Nakai
- Tokai University School of Medicine, Isehara, Japan,Collaborative Research Program Annulus Fibrosus Repair, AO Foundation, Davos, Switzerland
| | - D. Sakai
- Tokai University School of Medicine, Isehara, Japan,Collaborative Research Program Annulus Fibrosus Repair, AO Foundation, Davos, Switzerland
| | - L.M. Benneker
- Inselspital, University of Bern, Bern, Switzerland,Collaborative Research Program Annulus Fibrosus Repair, AO Foundation, Davos, Switzerland
| | - G. Zhou
- Shenzhen Key Laboratory of Anti-Aging and Regenerative Medicine, Department of Medical Cell Biology and Genetics, Health Sciences Centre, Shenzhen University, Shenzhen, China
| | - B. Li
- Orthopaedic Institute, Medical College, Soochow University, Suzhou, Jiangsu, China
| | - D. Eglin
- AO Research Institute Davos, Davos, Switzerland,Collaborative Research Program Annulus Fibrosus Repair, AO Foundation, Davos, Switzerland
| | - J.C. Iatridis
- Icahn School of Medicine at Mount Sinai, New York, USA,Collaborative Research Program Annulus Fibrosus Repair, AO Foundation, Davos, Switzerland
| | - M. Alini
- AO Research Institute Davos, Davos, Switzerland,Collaborative Research Program Annulus Fibrosus Repair, AO Foundation, Davos, Switzerland
| | - S. Grad
- AO Research Institute Davos, Davos, Switzerland,Collaborative Research Program Annulus Fibrosus Repair, AO Foundation, Davos, Switzerland
| | - Z. Li
- AO Research Institute Davos, Davos, Switzerland,Collaborative Research Program Annulus Fibrosus Repair, AO Foundation, Davos, Switzerland,Address for correspondence: Zhen Li, PhD, AO Research Institute Davos, Clavadelerstrasse 8, 7270, Davos Platz, Switzerland. Telephone number: +41 814142325
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19
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Silva MJ, Holguin N. Aging aggravates intervertebral disc degeneration by regulating transcription factors toward chondrogenesis. FASEB J 2019; 34:1970-1982. [PMID: 31909538 DOI: 10.1096/fj.201902109r] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2019] [Revised: 10/08/2019] [Accepted: 10/15/2019] [Indexed: 12/17/2022]
Abstract
Osterix is a critical transcription factor of mesenchymal stem cell fate, where its loss or loss of Wnt signaling diverts differentiation to a chondrocytic lineage. Intervertebral disc (IVD) degeneration activates the differentiation of prehypertrophic chondrocyte-like cells and inactivates Wnt signaling, but its interactive role with osterix is unclear. First, compared to young-adult (5 mo), mechanical compression of old (18 mo) IVD induced greater IVD degeneration. Aging (5 vs 12 mo) and/or compression reduced the transcription of osterix and notochordal marker T by 40-75%. Compression elevated the transcription of hypertrophic chondrocyte marker MMP13 and pre-osterix transcription factor RUNX2, but less so in 12 mo IVD. Next, using an Ai9/td reporter and immunohistochemical staining, annulus fibrosus and nucleus pulposus cells of young-adult IVD expressed osterix, but aging and compression reduced its expression. Lastly, in vivo LRP5-deficiency in osterix-expressing cells inactivated Wnt signaling in the nucleus pulposus by 95%, degenerated the IVD to levels similar to aging and compression, reduced the biomechanical properties by 45-70%, and reduced the transcription of osterix, notochordal markers and chondrocytic markers by 60-80%. Overall, these data indicate that age-related inactivation of Wnt signaling in osterix-expressing cells may limit regeneration by depleting the progenitors and attenuating the expansion of chondrocyte-like cells.
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Affiliation(s)
- Matthew J Silva
- Department of Biomedical Engineering, Orthopaedic Surgery, Musculoskeletal Research Center, Washington University, St. Louis, MO, USA
| | - Nilsson Holguin
- Department of Mechanical and Energy Engineering, Indiana Center for Musculoskeletal Health, IUPUI, Indianapolis, IN, USA.,Department of Anatomy and Cell Biology, Indiana Center for Musculoskeletal Health, IUPUI, Indianapolis, IN, USA
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20
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Torre OM, Mroz V, Benitez ARM, Huang AH, Iatridis JC. Neonatal annulus fibrosus regeneration occurs via recruitment and proliferation of Scleraxis-lineage cells. NPJ Regen Med 2019; 4:23. [PMID: 31885875 PMCID: PMC6925137 DOI: 10.1038/s41536-019-0085-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Accepted: 11/25/2019] [Indexed: 12/21/2022] Open
Abstract
Intervertebral disc (IVD) injuries are a cause of degenerative changes in adults which can lead to back pain, a leading cause of disability. We developed a model of neonatal IVD regeneration with full functional restoration and investigate the cellular dynamics underlying this unique healing response. We employed genetic lineage tracing in mice using Scleraxis (Scx) and Sonic hedgehog (Shh) to fate-map annulus fibrosus (AF) and nucleus pulposus (NP) cells, respectively. Results indicate functional AF regeneration after severe herniation injury occurs in neonates and not adults. AF regeneration is mediated by Scx-lineage cells that lose ScxGFP expression and adopt a stem/progenitor phenotype (Sca-1, days 3–14), proliferate, and then redifferentiate towards type I collagen producing, ScxGFP+ annulocytes at day 56. Non Scx-lineage cells were also transiently observed during neonatal repair, including Shh-lineage cells, macrophages, and myofibroblasts; however, these populations were no longer detected by day 56 when annulocytes redifferentiate. Overall, repair did not occur in adults. These results identify an exciting cellular mechanism of neonatal AF regeneration that is predominantly driven by Scx-lineage annulocytes.
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Affiliation(s)
- Olivia M Torre
- Leni & Peter W. May Department of Orthopaedics, Icahn School of Medicine at Mount Sinai, One Gustave Levy Place, Box 1188, New York, NY 10029-6574 USA
| | - Victoria Mroz
- Leni & Peter W. May Department of Orthopaedics, Icahn School of Medicine at Mount Sinai, One Gustave Levy Place, Box 1188, New York, NY 10029-6574 USA
| | - Anthony R Martinez Benitez
- Leni & Peter W. May Department of Orthopaedics, Icahn School of Medicine at Mount Sinai, One Gustave Levy Place, Box 1188, New York, NY 10029-6574 USA
| | - Alice H Huang
- Leni & Peter W. May Department of Orthopaedics, Icahn School of Medicine at Mount Sinai, One Gustave Levy Place, Box 1188, New York, NY 10029-6574 USA
| | - James C Iatridis
- Leni & Peter W. May Department of Orthopaedics, Icahn School of Medicine at Mount Sinai, One Gustave Levy Place, Box 1188, New York, NY 10029-6574 USA
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21
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Ashinsky BG, Gullbrand SE, Bonnevie ED, Mandalapu SA, Wang C, Elliott DM, Han L, Mauck RL, Smith HE. Multiscale and multimodal structure-function analysis of intervertebral disc degeneration in a rabbit model. Osteoarthritis Cartilage 2019; 27:1860-1869. [PMID: 31419488 PMCID: PMC6875634 DOI: 10.1016/j.joca.2019.07.016] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Revised: 07/11/2019] [Accepted: 07/18/2019] [Indexed: 02/02/2023]
Abstract
OBJECTIVES The objective of this study was to perform a quantitative analysis of the structural and functional alterations in the intervertebral disc during in vivo degeneration, using emerging tools that enable rigorous assessment from the microscale to the macroscale, as well as to correlate these outcomes with noninvasive, clinically relevant imaging parameters. DESIGN Degeneration was induced in a rabbit model by puncturing the annulus fibrosus (AF) with a 16-gauge needle. 2, 4, 8, and 12 weeks following puncture, degenerative changes in the discs were evaluated via magnetic resonance imaging (MRI), whole motion segment biomechanics, atomic force microscopy, histology and polarized light microscopy, immunohistochemistry, biochemical content, and second harmonic generation imaging. RESULTS Following puncture, degeneration was evident through marked changes in whole disc structure and mechanics. Puncture acutely compromised disc macro and microscale mechanics, followed by progressive stiffening and remodeling. Histological analysis showed substantial anterior fibrotic remodeling and osteophyte formation, as well as an overall reduction in disc height, and disorganization and infolding of the AF lamellae into the NP space. Increases in NP collagen content and aggrecan breakdown products were also noted within 4 weeks. On MRI, NP T2 was reduced at all post-puncture time points and correlated significantly with microscale indentation modulus. CONCLUSION This study defined the time dependent changes in disc structure-function relationships during IVD degeneration in a rabbit annular injury model and correlated degeneration severity with clinical imaging parameters. Our findings identified AF infolding and occupancy of the space as a principle mechanism of disc degeneration in response to needle puncture, and provide new insights to direct the development of novel therapeutics.
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Affiliation(s)
- Beth G. Ashinsky
- Department of Orthopaedic Surgery, McKay Orthopaedic Research Laboratory, University of Pennsylvania, Philadelphia, PA,Drexel University School of Biomedical Engineering, Philadelphia, PA,Translational Musculoskeletal Research Center, Corporal Michael J. Crescenz VA Medical Center, Philadelphia, PA
| | - Sarah E. Gullbrand
- Department of Orthopaedic Surgery, McKay Orthopaedic Research Laboratory, University of Pennsylvania, Philadelphia, PA,Translational Musculoskeletal Research Center, Corporal Michael J. Crescenz VA Medical Center, Philadelphia, PA
| | - Edward D. Bonnevie
- Department of Orthopaedic Surgery, McKay Orthopaedic Research Laboratory, University of Pennsylvania, Philadelphia, PA,Translational Musculoskeletal Research Center, Corporal Michael J. Crescenz VA Medical Center, Philadelphia, PA
| | - Sai A. Mandalapu
- Department of Orthopaedic Surgery, McKay Orthopaedic Research Laboratory, University of Pennsylvania, Philadelphia, PA,Translational Musculoskeletal Research Center, Corporal Michael J. Crescenz VA Medical Center, Philadelphia, PA
| | - Chao Wang
- Drexel University School of Biomedical Engineering, Philadelphia, PA
| | - Dawn M. Elliott
- Department of Biomedical Engineering, University of Delaware, Newark, DE
| | - Lin Han
- Drexel University School of Biomedical Engineering, Philadelphia, PA
| | - Robert L. Mauck
- Department of Orthopaedic Surgery, McKay Orthopaedic Research Laboratory, University of Pennsylvania, Philadelphia, PA,Translational Musculoskeletal Research Center, Corporal Michael J. Crescenz VA Medical Center, Philadelphia, PA
| | - Harvey E. Smith
- Department of Orthopaedic Surgery, McKay Orthopaedic Research Laboratory, University of Pennsylvania, Philadelphia, PA,Translational Musculoskeletal Research Center, Corporal Michael J. Crescenz VA Medical Center, Philadelphia, PA,Address correspondence to: Harvey E. Smith, University of Pennsylvania School of Medicine, Department of Orthopaedic Surgery, 3737 Market Street, 6 Floor, Philadelphia, PA 19104, T: 215-662-3340,
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22
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Zhang C, Smith MP, Zhou GK, Lai A, Hoy RC, Mroz V, Torre OM, Laudier DM, Bradley EW, Westendorf JJ, Iatridis JC, Illien-Jünger S. Phlpp1 is associated with human intervertebral disc degeneration and its deficiency promotes healing after needle puncture injury in mice. Cell Death Dis 2019; 10:754. [PMID: 31582730 PMCID: PMC6776553 DOI: 10.1038/s41419-019-1985-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Revised: 08/20/2019] [Accepted: 09/12/2019] [Indexed: 12/22/2022]
Abstract
Back pain is a leading cause of global disability and is strongly associated with intervertebral disc (IVD) degeneration (IDD). Hallmarks of IDD include progressive cell loss and matrix degradation. The Akt signaling pathway regulates cellularity and matrix production in IVDs and its inactivation is known to contribute to a catabolic shift and increased cell loss via apoptosis. The PH domain leucine-rich repeat protein phosphatase (Phlpp1) directly regulates Akt signaling and therefore may play a role in regulating IDD, yet this has not been investigated. The aim of this study was to investigate if Phlpp1 has a role in Akt dysregulation during IDD. In human IVDs, Phlpp1 expression was positively correlated with IDD and the apoptosis marker cleaved Caspase-3, suggesting a key role of Phlpp1 in the progression of IDD. In mice, 3 days after IVD needle puncture injury, Phlpp1 knockout (KO) promoted Akt phosphorylation and cell proliferation, with less apoptosis. At 2 and 8 months after injury, Phlpp1 deficiency also had protective effects on IVD cellularity, matrix production, and collagen structure as measured with histological and immunohistochemical analyses. Specifically, Phlpp1-deletion resulted in enhanced nucleus pulposus matrix production and more chondrocytic cells at 2 months, and increased IVD height, nucleus pulposus cellularity, and extracellular matrix deposition 8 months after injury. In conclusion, Phlpp1 has a role in limiting cell survival and matrix degradation in IDD and research targeting its suppression could identify a potential therapeutic target for IDD.
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Affiliation(s)
- Changli Zhang
- Emory University School of Medicine, Atlanta, GA, USA
- Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | | | - George K Zhou
- Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Alon Lai
- Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Robert C Hoy
- Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Victoria Mroz
- Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Olivia M Torre
- Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | | | | | | | | | - Svenja Illien-Jünger
- Emory University School of Medicine, Atlanta, GA, USA.
- Icahn School of Medicine at Mount Sinai, New York, NY, USA.
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23
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Borem R, Madeline A, Vela R, Gill S, Mercuri J. Multi-laminate annulus fibrosus repair scaffold with an interlamellar matrix enhances impact resistance, prevents herniation and assists in restoring spinal kinematics. J Mech Behav Biomed Mater 2019; 95:41-52. [PMID: 30953808 PMCID: PMC6510600 DOI: 10.1016/j.jmbbm.2019.03.030] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Revised: 03/03/2019] [Accepted: 03/29/2019] [Indexed: 12/19/2022]
Abstract
Focal defects in the annulus fibrosus (AF) of the intervertebral disc (IVD) arising from herniation have detrimental impacts on the IVD's mechanical function. Thus, biomimetic-based repair strategies must restore the mechanical integrity of the AF to help support and restore native spinal loading and motion. Accordingly, an annulus fibrosus repair patch (AFRP); a collagen-based multi-laminate scaffold with an angle-ply architecture has been previously developed, which demonstrates similar mechanical properties to native outer AF (oAF). To further enhance the mimetic nature of the AFRP, interlamellar (ILM) glycosaminoglycan (GAG) was incorporated into the scaffolds. The ability of the scaffolds to withstand simulated impact loading and resist herniation of native IVD tissue while contributing to the restoration of spinal kinematics were assessed separately. The results demonstrate that incorporation of a GAG-based ILM significantly increased (p < 0.001) the impact strength of the AFRP (2.57 ± 0.04 MPa) compared to scaffolds without (1.51 ± 0.13 MPa). Additionally, repair of injured functional spinal units (FSUs) with an AFRP in combination with sequestering native NP tissue and a full-thickness AF tissue plug enabled the restoration of creep displacement (p = 0.134), short-term viscous damping coefficient (p = 0.538), the long-term viscous (p = 0.058) and elastic (p = 0.751) damping coefficients, axial neutral zone (p = 0.908), and axial range of motion (p = 0.476) to an intact state. Lastly, the AFRP scaffolds were able to prevent native IVD tissue herniation upon application of supraphysiologic loads (5.28 ± 1.24 MPa). Together, these results suggest that the AFRP has the strength to sequester native NP and AF tissue and/or implants, and thus, can be used in a composite repair strategy for IVDs with focal annular defects thereby assisting in the restoration of spinal kinematics.
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Affiliation(s)
- Ryan Borem
- The Laboratory of Orthopaedic Tissue Regeneration & Orthobiologics, Department of Bioengineering, Clemson University, Clemson, SC, USA
| | - Allison Madeline
- The Laboratory of Orthopaedic Tissue Regeneration & Orthobiologics, Department of Bioengineering, Clemson University, Clemson, SC, USA
| | - Ricardo Vela
- The Laboratory of Orthopaedic Tissue Regeneration & Orthobiologics, Department of Bioengineering, Clemson University, Clemson, SC, USA
| | - Sanjitpal Gill
- The Laboratory of Orthopaedic Tissue Regeneration & Orthobiologics, Department of Bioengineering, Clemson University, Clemson, SC, USA; Department of Orthopaedic Surgery, Medical Group of the Carolinas-Pelham, Spartanburg Regional Healthcare System, Greer, SC, USA
| | - Jeremy Mercuri
- The Laboratory of Orthopaedic Tissue Regeneration & Orthobiologics, Department of Bioengineering, Clemson University, Clemson, SC, USA.
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24
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Mohanty S, Dahia CL. Defects in intervertebral disc and spine during development, degeneration, and pain: New research directions for disc regeneration and therapy. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2019; 8:e343. [PMID: 30977275 DOI: 10.1002/wdev.343] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Revised: 03/11/2019] [Accepted: 03/25/2019] [Indexed: 12/12/2022]
Abstract
Intervertebral discs are cartilaginous joints present between vertebrae. The centers of the intervertebral discs consist of a gelatinous nucleus pulposus derived from the embryonic notochord. With age or injury, intervertebral discs may degenerate, causing neurological symptoms including back pain, which affects millions of people worldwide. Back pain is a multifactorial disorder, and disc degeneration is one of the primary contributing factors. Recent studies in mice have identified the key molecules involved in the formation of intervertebral discs. Several of these key molecules including sonic hedgehog and Brachyury are not only expressed by notochord during development, but are also expressed by neonatal mouse nucleus pulposus cells, and are crucial for postnatal disc maintenance. These findings suggest that intrinsic signals in each disc may maintain the nucleus pulposus microenvironment. However, since expression of these developmental signals declines with age and degeneration, disc degeneration may be related to the loss of these intrinsic signals. In addition, findings from mouse and other mammalian models have identified similarities between the patterning capabilities of the embryonic notochord and young nucleus pulposus cells, suggesting that mouse is a suitable model system to understand disc development and aging. Future research aimed at understanding the upstream regulators of these developmental signals and the modes by which they regulate disc growth and maintenance will likely provide mechanistic insights into disc growth and aging. Further, such findings will likely provide insights relevant to the development of effective therapies for treatment of back pain and reversing the disc degenerative process. This article is categorized under: Birth Defects > Organ Anomalies Vertebrate Organogenesis > Musculoskeletal and Vascular Adult Stem Cells, Tissue Renewal, and Regeneration > Regeneration Adult Stem Cells, Tissue Renewal, and Regeneration > Stem Cells and Aging.
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Affiliation(s)
- Sarthak Mohanty
- Orthopedic Soft Tissue Research Program, Hospital for Special Surgery, New York, New York
| | - Chitra L Dahia
- Orthopedic Soft Tissue Research Program, Hospital for Special Surgery, New York, New York.,Department of Cell and Developmental Biology, Weill Cornell Medicine, Graduate School of Medical Science, New York, New York
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25
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Biomechanical test protocols to detect minor injury effects in intervertebral discs. J Mech Behav Biomed Mater 2019; 95:13-20. [PMID: 30947120 DOI: 10.1016/j.jmbbm.2019.03.024] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Revised: 02/26/2019] [Accepted: 03/22/2019] [Indexed: 01/21/2023]
Abstract
Intervertebral discs (IVDs) maintain flexibility of the spine and bear mechanical load. Annulus fibrosus (AF) defects are associated with IVD degeneration and herniation which disrupt biomechanical function and can cause pain. AF puncture injuries can induce IVD degeneration but are needed to inject therapies. Identifying small AF defects with biomechanical testing can be difficult because IVDs have a complex, composite structure and nonlinear biomechanical properties that are dependent on AF fiber tension. It remains unclear how choice of biomechanical testing protocols affect the sensitivity of biomechanical properties to AF injuries. This study determined whether axial preload or magnitude of cyclic axial or torsional testing affected the ability to detect minor AF defects in rat caudal motion segments using ex vivo biomechanical testing. Intact and injured motion segments were subjected to a repeated measures study design with multiple biomechanical testing protocols that varied axial tension-compression force amplitude (±1.6 N, ±8.0 N, ±16.0 N), axial preload (-1.6 N, -8.0 N, -16.0 N, corresponding to -0.1 MPa, -0.5 MPa, and -1.0 MPa, respectively), and torsional rotation angle (±10°, ±15°, and ±20°). Biomechanical properties obtained from the lowest force testing conditions for axial tension-compression (±1.6 N), axial preload (-1.6 N), and angular rotation (±10°) exhibited the largest differences in biomechanical properties between intact and injured conditions. Biomechanical properties determined under low axial force or torsion amplitudes involve less AF fiber tension and were most sensitive to injury. Low force testing protocols are recommended for detecting minor structural AF defects and may enable more precise assessments of IVD injuries, healing or repair.
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26
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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: 63] [Impact Index Per Article: 10.5] [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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