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Dian Zhang,1,2,* Minshan Feng,1,* Wei Liu,3,* Jie Yu,1 Xu Wei,1 Kexin Yang,1 Jiawen Zhan,1 Wei Peng,1,2 Mingyi Luo,1,2 Tao Han,1 Zhefeng Jin,1 He Yin,1 Kai Sun,1 Xunlu Yin,1 Liguo Zhu1 1Department of Spinal Surgery, Wangjing Hospital of China Academy of Chinese Medical Sciences, Beijing, People’s Republic of China; 2Wangjing Hospital of China Academy of Chinese Medical Sciences, Beijing University of Chinese Medicine, Beijing, People’s Republic of China; 3Department of Nursing, Shandong University of Traditional Chinese Medicine, Jinan, People’s Republic of China*These authors contributed equally to this workCorrespondence: Xunlu Yin; Liguo Zhu, Department of Spine, Wangjing Hospital of China Academy of Chinese Medical Sciences, Beijing, 100102, People’s Republic of China, Email yin_xun_lu@163.com; zhlg95@aliyun.comAbstract: Neck pain and low back pain are major challenges in public health, and intervertebral disc (IVD) biomechanics is an important multidisciplinary field. To date, no bibliometric literature review of the relevant literature has been performed, so we explored the emerging trends, landmark studies, and major contributors to IVD biomechanics research. We searched the Web of Science core collection (1900– 2022) using keywords mainly composed of “biomechanics” and “intervertebral disc” to conduct a bibliometric analysis of original papers and their references, focusing on citations, authors, journals, and countries/regions. A co-citation analysis and clustering of the references were also completed. A total of 3189 records met the inclusion criteria. In the co-citation network, cluster #0, labeled as “annulus fibrosus tissue engineering”, and cluster #1, labeled as “micromechanical environment”, were the biggest clusters. References by MacLean et al and Holzapfel et al were positioned exactly between them and had high betweenness centrality. There existed a research topic evolution between mechanobiology and mechanical repair strategies of IVDs, and the latter had been identified as an emerging trend in IVD biomechanics. Numerous landmark studies had contributed to several fields, including mechanical testing of normal and pathological IVDs, mechanical evaluation of new repair strategies and development of finite element model. Adams MA was the author most cited by IVD biomechanics papers. Spine, the European Spine Journal, and the Journal of Biomechanics were the three journals where the most original articles and their references have been published. The United States has contributed most to the literature (n = 1277 papers); however, the research output of China is increasing. In conclusion, the present study suggests that IVD repair is an emerging trend in IVD biomechanics.Keywords: emerging trend, co-citation, CiteSpace, annulus fibrosus

Long non-coding RNAs (lncRNAs) are related to a variety of human diseases. However, little is known about the role of lncRNA in intervertebral disc degeneration (IDD). LncRNA expression profile of human IDD were downloaded from Gene Expression Omnibus (GEO) database. Potential biomarkers and therapeutic drugs for IDD were analyzed by weighted gene co-expression network analysis (WGCNA), R software package Limma, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG). We identified 1455 differentially expressed genes and 423 differentially expressed lncRNAs. Twenty-six co-expression modules were obtained, among them, the tan, brown, and turquoise modules were most closely related to IDD. The turquoise module contained a large number of differential expressed lncRNAs and genes, these genes were mainly enriched in the MAPK signaling pathway, TGF-beta signaling pathway. Furthermore, we obtained 11,857 LmiRM-Degenerated, these lncRNAs and genes showed higher differential expression multiples and higher expression correlation. After constructing a disease-gene interaction network, 25 disease-specific genes and 9 disease-specific lncRNAs were identified. Combined with the drug-target gene interaction network, three drugs, namely, Calcium citrate, Calcium Phosphate, and Calcium phosphate dihydrate, which may have curative effects on IDD, were determined. Finally, a genetic diagnosis model and lncRNA diagnosis model with 100% diagnostic performance in both the training data set and the validation data set were established based on these genes and lncRNA. This study provided new diagnostic features for IDD and could help design personalized treatment of IDD.

STUDY DESIGN An ex vivo study of the rabbit's vertebral endplate. OBJECTIVE The aim of this study was to assess the effect of axial compression and distraction on vascular buds and vascular endothelial growth factor (VEGFA) expression of the vertebral endplate (VEP). SUMMARY OF BACKGROUND DATA The abnormal load can lead to intervertebral disc degeneration (IDD), whereas axial distraction can delay this process. The effects of different mechanical loads on the intervertebral disc (IVD) have been hypothesized to be related to changes in the vascular buds of the VEP; moreover, the process that might involve the vascular endothelial growth factor (VEGF) within the VEP. METHODS Rabbit spinal segments (n = 40) were harvested and randomly classified into four groups: Control group, no stress was applied; Group A, a constant compressive load applied; Group B, compression load removed for a fixed time daily on a continuous basis, and substituted with a distraction load for 30 minutes; and Group C, compression removed for 30 minutes for a fixed period daily on a continuous basis. Tissue specimens were collected before the culture (day 0) and on day 14 post-culture of each group for analysis of IVDs' morphology, and protein and mRNA expression of Aggrecan, COL2al, VEGFA, and vascular endothelial growth factor receptor 2 of the VEPs. RESULTS Application of axial distraction and dynamic load compression significantly delayed time- and constant compression-mediated VEP changes and IDD. Moreover, the degree of degeneration was associated with loss of vascular buds, as well as the downregulation of VEGFA and its receptor. CONCLUSION The regulation of vascular buds and VEGF expression in the VEP represents one of the mechanisms of axial distraction and dynamic loading.Level of Evidence: N/A.

Background Degenerative lumbar instability (DLI) is a common disease that causes low back pain (LBP) in clinic. It is difficult to completely recover from DLI, and it occurs repeatedly, which seriously affects the quality of life of patients. The epidemiological survey showed that 20–30% of low back pain was related to lumbar instability. Increasing evidence shows that seated lumbar rotation manipulation can effectively improve the clinical symptoms of patients with low back pain. The primary aim of this clinical trial is to observe the intervention effect of seated lumbar rotation manipulation on DLI patients. Method/design A total of 60 participants with DLI will be recruited and randomly allocated into the seated lumbar rotation manipulation group (the intervention group) or lumbar traction in supine position group (the control group) in this prospective, outcome assessor-blind, two-arm randomized controlled clinical trial. The treatment of the two groups lasted for 3 weeks, and the manipulation of the intervention group would be carried out once every other day, three times a week, a total of 9 times; the control group would be given lumbar traction once a day, five times a week, a total of 15 times. JOA (Japanese Orthopaedic Association) and VAS (Visual Analogue Scales) scores will be recorded as the primary outcomes before the treatment and at the 1st, 3rd, 5th, 8th, 10th, 12th, 15th, 17th, and 19th days after treatment and follow-up visit at the first, third, and sixth months. JOA efficacy evaluation standard will be used to evaluate the overall efficacy as the secondary outcomes. Discussion The results of this prospective, randomized controlled trial will provide a clinical evidence for the treatment of DLI with seated lumbar rotation manipulation. Trial registration Chinese Clinical Trial Registry ChiCTR2000032017. Registered on 18 April 2020, Prospective registration.

Summary of background dataThe vascular buds in the vertebral endplate (VEP) are the structural foundation of nutrient exchange in the intervertebral disc (IVD). VEGF is closely related to angiogenesis in the endplate and intervertebral disc degeneration (IDD).ObjectiveTo investigate the effects of static load on vascular buds and VEGF expression in the VEP and to further clarify the relation between IDD and VEGF.MethodsIVD motion segments were harvested from rabbit lumbar spines and cultured under no-loading conditions (controls) or in custom-made apparatuses under a constant compressive load (0.5 MPa) for up to 14 days. Tissue integrity and the number of vascular buds were determined, and the concentrations and expression of Aggrecan, COL2a1, and VEGFA in the VEPs were assessed after 3, 7, and 14 days of culturing and then compared with those of fresh tissues.ResultsUnder the constant compression, the morphological integrity of the VEPs was gradually disrupted, and immunohistochemistry results showed a significant decrease in the levels of Agg and COL2a1. During the static load, the number of vascular buds in the VEPs was gradually reduced from the early stage of culture, and ELISA showed that the constant compressive load caused a significant decrease in the VEGFA and VEGFR2 protein concentrations, which were consistent with the immunohistochemistry results. Western blot and RT-PCR results also showed that the loading state caused a significant decrease in VEGFA expression compared with that of fresh and control samples.ConclusionsConstant compression caused degeneration of the VEP as well as a decreased number of vascular buds, thereby accelerating disc degeneration. VEGFA is involved in this process. We anticipate that regulating the expression of VEGFA may improve the condition of the lesions to the vascular buds in the endplates, thus enhancing the nutritional supply function in IVD and providing new therapeutic targets and strategies for the effective prevention and treatment of IDD.

Low back pain is a major cause of disability worldwide. Although numerous potential biomarkers for the early diagnosis or treatment of intervertebral disc degeneration (IDD) have been identified subsequent to the development of molecular biology technologies, the mechanisms of IDD remain unknown. Published studies found the unbalance of anabolism and catabolism of annulus fibrosus (AF) played an important role in it. The present study was aimed to identify the potential targets and signaling pathways of IDD, through the combined analysis of differential expression and based on the Gene Expression Omnibus (GEO) dataset from NCBI. PPI Networks Analysis indicated that MMP2 and AGE-RAGE signaling pathway and estrogen signaling pathway may play important roles in initiation and development of IDD. This study forecasted the pathogenesis molecular mechanism of IDD and the potential prognostic and diagnostic biomarkers, but we need to make further molecular biological experiments to confirm our assumptions.

Background: The development of mechanically active culture systems helps increase the understanding of the role of mechanical stress in intervertebral disc (IVD) degeneration. Motion segment cultures allow for preservation of the native IVD structure, and adjacent vertebral bodies facilitate the application and control of mechanical loads. The purpose of this study was to establish loading and organ culture methods for rabbit IVD motion segments to study the effect of static load on the whole disc organ. Methods: IVD motion segments were harvested from rabbit lumbar spines and cultured in no-loading 6-well plates (control conditions) or custom-made apparatuses under a constant, compressive load (3 kg, 0.5 MPa) for up to 14 days. Tissue integrity, matrix synthesis, and the matrix gene expression profile were assessed after 3, 7, and 14 days of culturing and compared with those of fresh tissues. Results: The results showed that ex vivo culturing of motion segments preserved tissue integrity under no-loading conditions for 14 days whereas the static load gradually destroyed the morphology after 3 days. Proteoglycan contents were decreased under both conditions, with a more obvious decrease under static load, and proteoglycan gene expression was also downregulated. However, under static load, immunohistochemical staining intensity and collagen Type II alpha 1 (COL2A1) gene expression were significantly enhanced (61.54 ± 5.91, P = 0.035) and upregulated (1.195 ± 0.040, P = 0.000), respectively, compared with those in the controls (P < 0.05). In contrast, under constant compression, these trends were reversed. Our initial results indicated that short-term static load stimulated the synthesis of collagen Type II alpha 1; however, sustained constant compression led to progressive degeneration and specifically to a decreased proteoglycan content. Conclusions: A loading and organ culture system for ex vivo rabbit IVD motion segments was developed. Using this system, we were able to study the effects of mechanical stimulation on the biology of IVDs, as well as the pathomechanics of IVD degeneration.

Background Degenerative lumbar spondylolisthesis (DLS) is one of the common orthopedic diseases which causes low back pain in patients, which seriously affects people's daily life and work. As a method of conservative treatment of this disease, manipulation is widely used in clinical practice. We will summarize the current published evidence of manipulation in the treatment of DLS, and evaluate the effectiveness and safety of manipulation through systematic review and meta-analysis, so as to provide more reliable evidence for future clinical practice. Methods We will conduct a comprehensive search of the following 9 databases until January 2019: PubMed, Embase, Cochrane Library, ClinicalTrials.gov, Web of Science, Chinese National Knowledge Infrastructure, Chinese Science and Technique Journals Database, Wan Fang Database, and Chinese Biomedical Database. The 2 researchers will independently search, screen, extract data, and evaluate the quality of the literatures. The primary outcomes include clinical effectiveness, Japanese Orthopaedic Association scores, and the secondary outcomes include visual analog scale scores, symptom scores, and adverse events. Bias risk tools provided by Cochrane Collaboration will be used for literature quality assessment, and RevMan 5.3 software will be used for meta-analysis. Results The results of this study will systematically evaluate the effectiveness and safety of manipulation intervention for people with DLS, especially in improving lumbar function scores and pain scores. Conclusion The systematic review of this study will summarize the current published evidence of manipulation for the treatment of DLS, which can further guide the promotion and application of it. Ethics and dissemination This study does not require ethical approval and the results will be published in a peer-reviewed journal. Prospero registration number CRD42019139933.

The development of mechanically active culture systems helps in understanding of the role of mechanical stress in intervertebral disc (IVD) degeneration. Motion segment cultures facilitate the application and control of mechanical loads. The purpose of this study was to establish a culturing method for rabbit IVD motion segments to observe the effect of static load on the whole disc organ. Segments were cultured in custom-made apparatuses under a constant, compressive load (3 kg) for 2 weeks. Tissue integrity, matrix synthesis, and matrix gene expression profile were assessed and compared with fresh one. The results showedex vivoculturing of samples gradually destroyed the morphology. Proteoglycan contents and gene expression were decreased and downregulated obviously. However, immunohistochemical staining intensity and collagen type II gene expression were significantly enhanced and upregulated. In contrast, these trends were reversed under constant compression. These results indicated short-term static load stimulated the synthesis of type II collagen; however, constant compression led to progressive degeneration and specifically to proteoglycan. Through this study a loading and organ-culturing system forex vivorabbit IVD motion segments was developed, which can be used to study the effects of mechanical stimulation on the biology of IVDs and the pathomechanics of IVD degeneration.