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Chen H, Zhou Q, Pu X, Wang N, Wang S, Feng Z, Wang B, Zhu Z, Qiu Y, Sun X. Association between vertebral endplate defects and patient-reported symptoms: an immunohistochemical study investigating the COX-2/PGE-2/EP-4 axis. Spine J 2024:S1529-9430(24)00163-3. [PMID: 38631491 DOI: 10.1016/j.spinee.2024.04.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Revised: 04/07/2024] [Accepted: 04/07/2024] [Indexed: 04/19/2024]
Abstract
BACKGROUND CONTEXT Vertebral endplate defects are often implicated in degenerative disc disorders, yet their connection to patient-reported symptoms remains unclear. COX-2 and PGE-2 are known for their roles in inflammation and pain, with EP-4 receptor involvement in pain signaling. Examining their expression in vertebral endplate tissues may provide insights into pathomechanism of low back pain. PURPOSE To investigate the association between endplate defects and patient-reported symptoms and to further clarify the role of the COX-2/PGE-2/EP-4 axis in the pathogenesis of chronic low back pain. STUDY DESIGN/SETTING Retrospective study. PATIENT SAMPLE A total of 71 patients who had undergone single-level L4/5 or L5/S1 modified laminectomy decompression preserving proximal upper laminae and transforaminal lumbar interbody fusion surgery were included in this study, including 18 patients diagnosed with lumbar disc herniation, 19 with lumbar disc herniation accompanied by degenerative lumbar spinal stenosis, and 34 with degenerative spondylolisthesis. OUTCOME MEASURES Demographic data, Pfirrmann grade, Modic changes, endplate defect score, visual analog scale (VAS) for back and leg pain, and Oswestry Disability Index (ODI) before surgery, 3-month and 6-month follow-up, and the percentage of immune-positive cells (COX-2, PGE-2, and EP-4) in endplate tissue sections. METHODS Patients were divided into defect and non-defect groups according to endplate morphology on lumbar MR. All intraoperative endplate specimens were immediately fixed in 10% formaldehyde, and then embedded in paraffin 3 days later for tissue sections. The outcome measures were compared between the defect group and non-defect group. Data were analyzed using independent t-tests and χ² tests. Pearson's rank correlation test was used to assess correlations between patient-reported symptoms and the percentage of immune-positive cells in the groups. Multivariable logistic regression models using the forward stepwise likelihood ratio method were used to identify the factors that were independently associated with endplate defects. RESULTS The age of Defect group was significantly higher than that of non-defect group (52.5±7.7 vs. 57.2±9.1. p=.024). There were no significant differences in gender, diagnosis, BMI, comorbidities, or surgical level between the two groups. Modic changes (Type Ⅱ/Type Ⅲ) were more common in patients of Defect group than non-defect group (38.5% vs. 11.1%, p<.001), and so was disc degeneration (Pfirrmann grade Ⅳ/Ⅴ) (69.2% vs. 33.3%, p<.001). Defect group had significantly higher VAS-Back (6.5±2.0 vs. 4.9±1.6, p<.001) and ODI scores (62.9±10.7 vs. 45.2±14.8, p<.001) than non-defect group, while there was no significant differences between the two groups during the 3 and 6-month follow-up after surgery. Histologically, Defect group was characterized by upregulation of COX-2, PGE-2, and EP-4 in endplate tissue sections. Both in defect and non-defect groups, VAS-Back showed moderate positive correlations with the expressions of COX-2 (r=0.643; r=0.558, p both<0.001), PGE-2 (r=0.611; r=0.640, p both<.001), and EP-4 (r=0.643; r=0.563, p both<.001). Multivariate regression analyses reveled that percentage of COX-2-positive cells was associated with endplate defects (OR=1.509, 95%CI [1.048-2.171], p=0.027), as well as percentage of PGE-2-positive (OR=1.291, 95%CI [1.106-1.508], p=.001) and EP-4-positive cells (OR=1.284, 95%CI [1.048∼2.171], p=.003). CONCLUSIONS Patients with endplate defects had worse quality of life, more severe disc degeneration and Modic changes, and up-regulated COX-2/PGE-2/EP-4 axis expression in cartilage endplates in patients with defected endplates. Inflammatory factors may significantly contribute to the onset and progression of chronic low back pain in patients with endplate defects, consequently impacting patient-reported symptoms.
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Affiliation(s)
- Haojie Chen
- Division of Spine Surgery, Department of Orthopedic Surgery, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, China
| | - Qingshuang Zhou
- Division of Spine Surgery, Department of Orthopedic Surgery, Nanjing Drum Tower Hospital Clinical College of Jiangsu University, Nanjing, China
| | - Xiaojiang Pu
- Division of Spine Surgery, Department of Orthopedic Surgery, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, China
| | - Nannan Wang
- Division of Spine Surgery, Department of Orthopedic Surgery, Nanjing Drum Tower Hospital Clinical College of Nanjing University of Chinese Medicine, China
| | - Sinian Wang
- Division of Spine Surgery, Department of Orthopedic Surgery, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, China
| | - Zhenhua Feng
- Division of Spine Surgery, Department of Orthopedic Surgery, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, China
| | - Bin Wang
- Division of Spine Surgery, Department of Orthopedic Surgery, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, China
| | - Zezhang Zhu
- Division of Spine Surgery, Department of Orthopedic Surgery, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, China
| | - Yong Qiu
- Division of Spine Surgery, Department of Orthopedic Surgery, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, China
| | - Xu Sun
- Division of Spine Surgery, Department of Orthopedic Surgery, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing, China.
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Kuchynsky K, Stevens P, Hite A, Xie W, Diop K, Tang S, Pietrzak M, Khan S, Walter B, Purmessur D. Transcriptional profiling of human cartilage endplate cells identifies novel genes and cell clusters underlying degenerated and non-degenerated phenotypes. Arthritis Res Ther 2024; 26:12. [PMID: 38173036 PMCID: PMC10763221 DOI: 10.1186/s13075-023-03220-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Accepted: 11/22/2023] [Indexed: 01/05/2024] Open
Abstract
BACKGROUND Low back pain is a leading cause of disability worldwide and is frequently attributed to intervertebral disc (IVD) degeneration. Though the contributions of the adjacent cartilage endplates (CEP) to IVD degeneration are well documented, the phenotype and functions of the resident CEP cells are critically understudied. To better characterize CEP cell phenotype and possible mechanisms of CEP degeneration, bulk and single-cell RNA sequencing of non-degenerated and degenerated CEP cells were performed. METHODS Human lumbar CEP cells from degenerated (Thompson grade ≥ 4) and non-degenerated (Thompson grade ≤ 2) discs were expanded for bulk (N=4 non-degenerated, N=4 degenerated) and single-cell (N=1 non-degenerated, N=1 degenerated) RNA sequencing. Genes identified from bulk RNA sequencing were categorized by function and their expression in non-degenerated and degenerated CEP cells were compared. A PubMed literature review was also performed to determine which genes were previously identified and studied in the CEP, IVD, and other cartilaginous tissues. For single-cell RNA sequencing, different cell clusters were resolved using unsupervised clustering and functional annotation. Differential gene expression analysis and Gene Ontology, respectively, were used to compare gene expression and functional enrichment between cell clusters, as well as between non-degenerated and degenerated CEP samples. RESULTS Bulk RNA sequencing revealed 38 genes were significantly upregulated and 15 genes were significantly downregulated in degenerated CEP cells relative to non-degenerated cells (|fold change| ≥ 1.5). Of these, only 2 genes were previously studied in CEP cells, and 31 were previously studied in the IVD and other cartilaginous tissues. Single-cell RNA sequencing revealed 11 unique cell clusters, including multiple chondrocyte and progenitor subpopulations with distinct gene expression and functional profiles. Analysis of genes in the bulk RNA sequencing dataset showed that progenitor cell clusters from both samples were enriched in "non-degenerated" genes but not "degenerated" genes. For both bulk- and single-cell analyses, gene expression and pathway enrichment analyses highlighted several pathways that may regulate CEP degeneration, including transcriptional regulation, translational regulation, intracellular transport, and mitochondrial dysfunction. CONCLUSIONS This thorough analysis using RNA sequencing methods highlighted numerous differences between non-degenerated and degenerated CEP cells, the phenotypic heterogeneity of CEP cells, and several pathways of interest that may be relevant in CEP degeneration.
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Affiliation(s)
- Kyle Kuchynsky
- Department of Biomedical Engineering, The Ohio State University, 3016 Fontana Laboratories, 140 W. 19th Ave, Columbus, OH, 43210, USA
| | - Patrick Stevens
- Department of Biomedical Informatics, The Ohio State University, Columbus, OH, USA
| | - Amy Hite
- Department of Biomedical Informatics, The Ohio State University, Columbus, OH, USA
| | - William Xie
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH, USA
| | - Khady Diop
- Department of Biomedical Engineering, The Ohio State University, 3016 Fontana Laboratories, 140 W. 19th Ave, Columbus, OH, 43210, USA
| | - Shirley Tang
- Department of Biomedical Engineering, The Ohio State University, 3016 Fontana Laboratories, 140 W. 19th Ave, Columbus, OH, 43210, USA
| | - Maciej Pietrzak
- Department of Biomedical Informatics, The Ohio State University, Columbus, OH, USA
- The James Comprehensive Cancer Center, The Ohio State University, Columbus, OH, USA
| | - Safdar Khan
- Department of Orthopaedics, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Benjamin Walter
- Department of Biomedical Engineering, The Ohio State University, 3016 Fontana Laboratories, 140 W. 19th Ave, Columbus, OH, 43210, USA
| | - Devina Purmessur
- Department of Biomedical Engineering, The Ohio State University, 3016 Fontana Laboratories, 140 W. 19th Ave, Columbus, OH, 43210, USA.
- Department of Orthopaedics, The Ohio State University Wexner Medical Center, Columbus, OH, USA.
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Wang D, Lai A, Gansau J, Seifert AC, Munitz J, Zaheer K, Bhadouria N, Lee Y, Nasser P, Laudier DM, Holguin N, Hecht AC, Iatridis JC. Lumbar endplate microfracture injury induces Modic-like changes, intervertebral disc degeneration and spinal cord sensitization - an in vivo rat model. Spine J 2023; 23:1375-1388. [PMID: 37086976 PMCID: PMC10524828 DOI: 10.1016/j.spinee.2023.04.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Revised: 04/05/2023] [Accepted: 04/18/2023] [Indexed: 04/24/2023]
Abstract
BACKGROUND CONTEXT Endplate (EP) injury plays critical roles in painful IVD degeneration since Modic changes (MCs) are highly associated with pain. Models of EP microfracture that progress to painful conditions are needed to better understand pathophysiological mechanisms and screen therapeutics. PURPOSE Establish in vivo rat lumbar EP microfracture model and assess crosstalk between IVD, vertebra and spinal cord. STUDY DESIGN/SETTING In vivo rat EP microfracture injury model with characterization of IVD degeneration, vertebral remodeling, spinal cord substance P (SubP), and pain-related behaviors. METHODS EP-injury was induced in 5 month-old male Sprague-Dawley rats L4-5 and L5-6 IVDs by puncturing through the cephalad vertebral body and EP into the NP of the IVDs followed by intradiscal injections of TNFα (n=7) or PBS (n=6), compared with Sham (surgery without EP-injury, n=6). The EP-injury model was assessed for IVD height, histological degeneration, pain-like behaviors (hindpaw von Frey and forepaw grip test), lumbar spine MRI and μCT, and spinal cord SubP. RESULTS Surgically-induced EP microfracture with PBS and TNFα injection induced IVD degeneration with decreased IVD height and MRI T2 signal, vertebral remodeling, and secondary damage to cartilage EP adjacent to the injury. Both EP injury groups showed MC-like changes around defects with hypointensity on T1-weighted and hyperintensity on T2-weighted MRI, suggestive of MC type 1. EP injuries caused significantly decreased paw withdrawal threshold, reduced axial grip, and increased spinal cord SubP, suggesting axial spinal discomfort and mechanical hypersensitivity and with spinal cord sensitization. CONCLUSIONS Surgically-induced EP microfracture can cause crosstalk between IVD, vertebra, and spinal cord with chronic pain-like conditions. CLINICAL SIGNIFICANCE This rat EP microfracture model was validated to induce broad spinal degenerative changes that may be useful to improve understanding of MC-like changes and for therapeutic screening.
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Affiliation(s)
- Dalin Wang
- Leni and Peter W. May Department of Orthopaedics, Icahn School of Medicine at Mount Sinai, One Gustave Levy Place, Box 1188, New York, NY 10029 USA; Department of Orthopaedics, Nanjing First Hospital, Nanjing Medical University, 68 Changle Road, Nanjing, Jiangsu 210006, China; Department of Orthopedic Surgery, University of Kansas Medical Center, 3901 Rainbow Blvd, Kansas City, KS 66160, USA
| | - Alon Lai
- Leni and Peter W. May Department of Orthopaedics, Icahn School of Medicine at Mount Sinai, One Gustave Levy Place, Box 1188, New York, NY 10029 USA
| | - Jennifer Gansau
- Leni and Peter W. May Department of Orthopaedics, Icahn School of Medicine at Mount Sinai, One Gustave Levy Place, Box 1188, New York, NY 10029 USA
| | - Alan C Seifert
- Department of Radiology, Icahn School of Medicine at Mount Sinai, Leon and Norma Hess Center for Science and Medicine, 1470 Madison Avenue, 1st Floor, New York, NY 10029, USA
| | - Jazz Munitz
- Department of Radiology, Icahn School of Medicine at Mount Sinai, Leon and Norma Hess Center for Science and Medicine, 1470 Madison Avenue, 1st Floor, New York, NY 10029, USA
| | - Kashaf Zaheer
- Leni and Peter W. May Department of Orthopaedics, Icahn School of Medicine at Mount Sinai, One Gustave Levy Place, Box 1188, New York, NY 10029 USA
| | - Neharika Bhadouria
- Leni and Peter W. May Department of Orthopaedics, Icahn School of Medicine at Mount Sinai, One Gustave Levy Place, Box 1188, New York, NY 10029 USA; School of Mechanical Engineering, Purdue University, 610 Purdue Mall, West Lafayette, IN 47907, USA
| | - Yunsoo Lee
- Leni and Peter W. May Department of Orthopaedics, Icahn School of Medicine at Mount Sinai, One Gustave Levy Place, Box 1188, New York, NY 10029 USA
| | - Philip Nasser
- Leni and Peter W. May Department of Orthopaedics, Icahn School of Medicine at Mount Sinai, One Gustave Levy Place, Box 1188, New York, NY 10029 USA
| | - Damien M Laudier
- Leni and Peter W. May Department of Orthopaedics, Icahn School of Medicine at Mount Sinai, One Gustave Levy Place, Box 1188, New York, NY 10029 USA
| | - Nilsson Holguin
- Leni and Peter W. May Department of Orthopaedics, Icahn School of Medicine at Mount Sinai, One Gustave Levy Place, Box 1188, New York, NY 10029 USA
| | - Andrew C Hecht
- Leni and Peter W. May Department of Orthopaedics, Icahn School of Medicine at Mount Sinai, One Gustave Levy Place, Box 1188, New York, NY 10029 USA
| | - James C Iatridis
- Leni and Peter W. May Department of Orthopaedics, Icahn School of Medicine at Mount Sinai, One Gustave Levy Place, Box 1188, New York, NY 10029 USA.
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