Finite element model establishment and stress analysis of lumbar-sacral intervertebral disc in ankylosing spondylitis / 中国组织工程研究

BACKGROUND:Ankylosing spondylitis is a chronic inflammatory disease with chronic rheumatic immunity.Soft tissue ossification and fusion and spinal stiffness can cause biomechanical changes. OBJECTIVE:To reconstruct the lumbar-sacral intervertebral disc in ankylosing spondylitis patients with lumbar kyphosis by finite element analysis,and to study the range of motion of each segment of T11-S1 and the biomechanical characteristics of annulus fibrosus and nucleus pulposus. METHODS:The imaging data were obtained from an ankylosing spondylitis patient with lumbar kyphosis.The original CT image data of continuously scanned spine were imported into Mimics 21.0 in DICOM format,and T11-S1 was reconstructed respectively.The established model was imported into 3-Matic software in the format of"Stl"to reconstruct the intervertebral disc,and the fibrous intervertebral disc model was obtained.The improved model was further imported into Hypermesh software,and the vertebra,nucleus pulposus,annulus fibrosus and ligament were mesh-divided.After the material properties were given,the model was imported into ABAQUS software to observe the range of motion of each vertebral body in seven different working conditions of T11-S1,and analyze the biomechanical characteristics of each segment of annulus fibrosus and nucleus pulposus. RESULTS AND CONCLUSION:(1)The range of motion of L1 vertebrae was higher than that of other vertebrae under six different working conditions:extension,forward flexion,rotation(left and right),and lateral flexion(left and right).The maximum range of motion was 2.18° during L1 vertebral flexion,and the minimum range of motion was 0.12° during L5 vertebral extension.(2)The annular fiber flexion at L2-L3 segments was greater than the extension(P<0.05),and the annular fiber flexion at L3-L4 and L4-L5 segments was less than the extension(P<0.05).The left rotation of L1-L2 annular fibers was greater than the right rotation(P<0.05).The left flexion of the annulus was greater than the right flexion in L1-L2,L2-L3,L3-L4,L4-L5 and L5-S1 segments(P<0.05).(3)The nucleus pulposus stresses of T11-L12,L1-L2,L2-L3,L3-L4 and L4-L5 segments in forward flexion were greater than in extension(P<0.05).The left rotation of T12-L1 and L3-L4 segments was smaller than the right rotation(P<0.05),and that of T11-T12,L1-L2,and L2-L3 segments was larger than the right rotation(P<0.05).The left flexion was larger than the right flexion in the T11-S1 segment.(4)It is concluded that in ankylosing spondylitis patients with lumbar kyphosis,the minimum range of motion of the vertebral body is located at the L5 vertebral body in extension.To prevent fractures,it is recommended to avoid exercise in the extension position.During the onset of lumbar kyphosis in patients with ankylosing spondylitis,the maximum stress of the annulus fibrosus and nucleus pulposus is located in the L1-L2 segment,which is fixed and will not alter with the change of body position.The late surgical treatment and correction of deformity should focus on releasing the pressure of the annulus fibrosus and nucleus pulposus in this segment to avoid the rupture of the annulus fibrosus and the injury of the nucleus pulposus.

Effects of static traction on the nucleus pulposus and annulus fibrosus of the rat intervertebral disc / 中国组织工程研究

BACKGROUND:Traction is clinically used for the early treatment of intervertebral disc degeneration,but its effect on the normal intervertebral disc remains unknown.Whether it directly causes intervertebral disc degeneration or has a positive effect is the key point of this study. OBJECTIVE:To design a static traction model and observe the effect of static traction on the nucleus pulposus and annulus fibrosus of the intervertebral disc METHODS:Twenty Sprague-Dawley rats,3 months of age,were included in the study.The intervertebral disc spaces between 7/8,8/9 and 9/10 were stretched by 1 mm,and the intervertebral disc spaces between 6/7 and 10/11 were used as control.Five rats were randomly selected at 2,4,6,and 8 weeks of traction to perform MRI T2-weighted scans of the caudal vertebra,tissue section staining,and RT-PCR gene assays for anabolic metabolism to observe the effects of static traction on the nucleus pulposus and annulus fibrosus of the intervertebral disc. RESULTS AND CONCLUSION:After short-term static traction of the rat caudal vertebra,the T2-weighted image signal in the nucleus pulposus region was enhanced.During the traction period,nucleus pulposus cells grew well,the intercellular matrix was abundant,and the annulus fibrosus arranged regularly.The RT-PCR results showed that after traction,the mRNA expression of proteoglycan increased,the expression of matrix metalloproteinase-3 decreased,the expression of type Ⅰ and Ⅱ collagen decreased,and the expression of matrix metalloproteinase-13 increased and tissue inhibitor of matrix metalloproteinase 1 increased.These gene results also indicated that traction made proteoglycan more inclined to an anabolic state,and type Ⅰ and Ⅱ collagen more inclined to a catabolic state.To conclude,static traction promotes proteoglycan anabolism making the nucleus pulposus moist.

Cadmium promotes senescence of annulus fibrosus cells via activation of PI3K/Akt signaling pathway / 中国组织工程研究

BACKGROUND:Cadmium is a common environmental pollutant,which can damage multiple organs and tissues,such as the kidney and bone,but its effect on annulus fibrosus cells in the intervertebral disc has been less reported. OBJECTIVE:To investigate the effect of cadmium chloride on the senescence of annulus fibrosus cells and the role of PI3K/Akt signaling pathway. METHODS:Annulus fibrosus cells from Sprague-Dawley rat intervertebral discs were harvested and passage 3 cells were intervened with different concentrations of cadmium chloride(0,1,5,10,20 μmol/L).Cell viability and proliferation were detected by cell counting kit-8 assay.Transcriptome sequencing and Kyoto Encyclopedia of Genes and Genomes functional enrichment analysis were performed on annulus fibrosus cells with or without cadmium chloride addition.Passage 3 annulus fibrosus cells were divided into control group,cadmium chloride group and LY294002 group.Cell proliferation rate was detected by EdU method,positive cell rate was detected by senescence-associated β-galactosidase staining,and expressions of senescence-associated proteins(p16,p21 and p53)and p-Akt at protein and mRNA levels were measured by western blot,RT-PCR and immunofluorescence. RESULTS AND CONCLUSION:5 μmol/L cadmium chloride could inhibit the proliferation of annulus fibrosus cells.Results from the Kyoto Encyclopedia of Genes and Genomes functional enrichment analysis showed that the main signal transduction pathways included PI3K/Akt,cell cycle and p53 signaling pathways,which were related to cell senescence and proliferation.PI3K/Akt signaling pathways with significant differential expression were selected for validation.Compared with the control group,the EdU-positive rate was significantly decreased in the cadmium chloride group(P<0.05),while the β-galactosidase-positive rate,the expression of senescence-associated proteins(p16,p21 and p53)and p-Akt significantly increased(P<0.05).Compared with the cadmium chloride group,the EdU-positive rate and p-Akt expression were significantly decreased in the LY294002 group(P<0.05),while the β-galactosidase-positive rate and the expression of senescence-associated proteins(p16,p21 and p53)significantly increased(P<0.05).To conclude,cadmium chloride can regulate the senescence of annulus fibrosus cells by activating the PI3K/Akt signaling pathway,thereby inducing the occurrence and progression of intervertebral disc degeneration.

Yougui Pill in the treatment of lumbar disc herniation:network pharmacological analysis of active ingredients and potential targets / 中国组织工程研究

BACKGROUND:Yougui Pill is a famous formula of the Chinese traditional medicine,which has good efficacy for lumbar disc herniation due to kidney yang insufficiency. OBJECTIVE:To investigate the potential targets and mechanism of action of Yougui Pill in the treatment of lumbar disc herniation by using network pharmacology and molecular docking technology,and verified by animal experiments. METHODS:(1)Network pharmacological analysis:We obtained the active ingredients and targets of Yougui Pill from TCMSP and other databases,collected genes related to lumbar disc herniation from GeneCards database,and took the intersection of the two for the topological analysis to derive the main active ingredients and core therapeutic targets.Gene ontology function analysis and Kyoto encyclopedia of genes and genomes pathway enrichment analysis were performed using R software.(2)Molecular docking:Autodock and Pymol software were utilized for the prediction of molecular binding energy of TCM active ingredients to core therapeutic targets.(3)Animal experiments:Eighteen Sprague-Dawley rats were randomly divided into a control group,a degeneration group and a Yougui Pill group,with 6 rats in each group.A rat model of intervertebral disc degeneration was prepared by fiber puncture method in the degeneration and Yougui Pill groups.At 2 weeks after modeling,Yougui Pill was given by gavage in the Yougui Pill group,once a day for 2 consecutive weeks.The level of tumor necrosis factor-α in serum was detected by the ELISA method,and morphological changes of the annulus fibrosus and nucleus pulposus cells were observed using hematoxylin-eosin staining. RESULTS AND CONCLUSION:There were 90 active ingredients and 64 targets,and the main active ingredients were found to be quercetin,kaempferol,β-carotene,soybean flavonoid,and 4'-O-methylnyasol.The core targets of Yougui Pill for the treatment of lumbar disc herniation were interleukin 6,tumor necrosis factor-α,AKT1,interleukin 1B,and vascular endothelial growth factor A.Enrichment analysis revealed that the intersecting genes might be expressed through the interleukin-17 signaling pathway,tumor necrosis factor signaling pathway,MAPK signaling pathway,PI3K-AKT signaling pathway,and other signaling pathways to improve intervertebral disc degeneration.The molecular docking test verified that quercetin,kaempferol,and β-carotene had strong binding ability to the core targets.Animal experiments showed that the level of serum tumor necrosis factor α in the degeneration group was higher than that in the control group(P<0.05),and the level of serum tumor necrosis factor α in the Yougui Pill group was lower than that in the degeneration group(P<0.05).Hematoxylin-eosin staining showed that the fibrous annulus of the intervertebral discs and the structure of the nucleus pulposus in the degeneration group were destroyed,and the number of nucleus pulposus cells was reduced;there was a tendency to reconstructing the fibrous annulus of the intervertebral discs in the Yougui Pill group,and the number of nucleus pulposus cells increased compared with the degeneration group.To conclude,Yougui Pill may treat lumbar disc herniation by improving disc degeneration through the effects of quercetin,kaempferol,beta-carotene and other key active ingredients on core targets such as tumor necrosis factor.

Isolation,purification and identification of rat annulus fibrosus-derived stem cells by adherent method combined with fibronectin differential adhesion method / 中国组织工程研究

BACKGROUND:At present,bone marrow mesenchymal stem cells are the main seed cells used in cell therapy for the treatment of intervertebral disc degeneration.However,the use of bone marrow mesenchymal stem cells as seed cells for the regeneration of fibrous rings is at risk of heterotopic ossification and teratoma at the repair site.Therefore,it is of great economic and social significance to find a new kind of seed cells for tissue engineering of annulus fibrosus for the treatment of intervertebral disc degeneration. OBJECTIVE:To isolate and purify rat annulus fibrosus-derived stem cells by adherent method combined with fibronectin differential adhesion screening method,and to observe its purification effect and biological characteristics. METHODS:Annulus fibrosus tissue was obtained from a SD rat intervertebral disc.Primary annulus fibrosus-derived stem cells were obtained by the mechanical-enzymatic digestion method.Annulus fibronectin differential adhesion method was used to purify annulus fibrosus-derived stem cells.Morphological changes and proliferation of cells were observed through a microscope.The expression levels of stem cell markers were detected by immunofluorescence technique and qPCR.The screened cells were subjected to multi-lineage cell differentiation and characteristic gene detection. RESULTS AND CONCLUSION:(1)The purified cells grew well,and most of them were angular and star-shaped multi-process cells,which had good proliferation ability.(2)Cells were positive for cell membrane surface antigens CD73,CD90 and CD105,while negative for CD45 and CD34.(3)After specific induction,cells could successfully differentiate into osteoblasts,chondroblasts and lipoblasts.(4)Collagen-I,Runx-2 after osteogenic induction,Collagen Ⅱ,Sox-9 after chondrogenic induction,and PPAR-γ and LPL after lipogenic induction were highly expressed in cells,and the difference was significant compared with that before induction(P<0.05).(5)These findings confirm that the adherent method combined with fibronectin differential adhesion method is effective enough to screen,isolate and purify rat annulus fibrosus-derived stem cells,and has good cell biological properties,good proliferation ability and multiple differentiation potential.

MicroRNA-887-3p Inhibited MDM4 Expression and Proliferation but Promoted Apoptosis of Intervertebral Disc Annulus Fibrosus Cells in Rats / 实验动物与比较医学

ObjectiveTo investigate the effects of microRNA (miRNA, miR)-887-3p on the proliferation and apoptosis of rat intervertebral disc annulus fibrosus cells and its underlying molecular mechanism. MethodsAnnulus fibrosus tissues were obtained from 8-week-old SPF-grade SD male rats, centrifuged to prepare and identify annulus fibrosus cells. Rats in the experiment were randomly divided into four groups: a Normal group consisting of primary annulus fibrosus cells without any treatment; a Control group treated with 10 ng/mL interleukin-1β (IL-1β) for 24 hours to establish a degenerative cell model; an interference group (miR-887-3p inhibitor) transfected with miR-887-3p inhibitor using Lipo3000 based on the Control group; and an overexpression group (miR-887-3p mimics) transfected with miR-887-3p mimics using Lipo3000 based on the Control group. CCK-8 assay was used to assess cell viability; flow cytometry was used to measure cell apoptosis rates; real-time fluorescence quantitative PCR (qPCR) was used to detect the expression levels of miR-887-3p and murine double minute 4 (MDM4) mRNA; Western blotting was used to measure the protein expression levels of MDM4, Bcl-2, and Caspase-3. ResultsImmunofluorescence staining of isolated and cultured cells revealed a Collagen I positive rate of over 90% in rat intervertebral disc annulus fibrosus cells, indicating a cell purity level greater than 90%. Real-time fluorescence qPCR results showed that after establishing an annulus fibrosus degenerative cell model using IL-1β, the expression level of miR-887-3p significantly increased compared to the Normal group (P<0.001). Compared to the Control group, transfection with miR-887-3p inhibitor resulted in a significant decrease in its expression level (P<0.001). The CCK-8 assay showed that compared to the Normal group, cell viability significantly decreased in the Control group (P<0.001). Compared to the Control group, cell proliferation ability significantly increased after miR-887-3p inhibition, and significantly decreased after overexpression of miR-887-3p. Flow cytometry results revealed that compared to the Normal group, the apoptosis rate in the Control group significantly increased (P<0.001). Compared to the Control group, the cell apoptosis rate significantly decreased in the miR-887-3p interference group (P<0.001) and increased in the overexpression group (P<0.001). Western blotting analysis showed that compared to the Normal group, Bcl-2 expression level significantly decreased (P<0.001) and Caspase-3 expression level significantly increased (P<0.001) in the Control group. Compared to the Control group, Bcl-2 and MDM4 expression levels significantly increased (P<0.01), and Caspase-3 expression level significantly decreased (P<0.01) in the miR-887-3p interference group; whereas in the overexpression group, Bcl‑2 and MDM4 expression levels significantly decreased (P<0.05), and Caspase-3 levels significantly increased (P<0.05). Real-time fluorescence qPCR and protein immunoblotting results showed that after interfering with miR-887-3p, the expression of MDM4 protein and mRNA increased (P<0.001); after overexpressing miR-887-3p, their expression decreased (protein, P<0.01; mRNA, P<0.001). ConclusionMiR-887-3p may modulate the cell proliferation and apoptosis of rat intervertebral disc annulus fibrosus cells by regulating MDM4 expression, thereby influencing the development and progression of disc degeneration.

Intervertebral disc tissue engineering based on polymer materials: Research focus and hot spots / 中国组织工程研究

BACKGROUND: In recent years, the rapid development of tissue engineering technology provides a new idea for the treatment of intervertebral disc degeneration; that is, biomaterials are used to reconstruct the damaged intervertebral disc structure. OBJECTIVE: To summarize polymer materials which are applicable for intervertebraltissue engineering construction, and overview the advantages, disadvantages and application progress of each material. METHODS: We searched related articles from inception to February 2020 in PubMed, Web of Science and CNKI databases with “polymer, intervertebral disc, tissue engineering, nucleus pulposus, annulus fibrosus” as English and Chinese key words. Initially 189 related articles were searched, and 109 eligible articles were included in final analysis according to inclusion and exclusion criteria. RESULTS AND CONCLUSION: Intervertebral disc is composed of inner soft nucleus pulposus and outer stiff annulus fibrosus. Accordingly, it requires two components with different structures and functions to reconstruct a complete intervertebral disc with tissue engineering method. Chitosan, alginate and hyaluronic acid are considered as optimal materials for nucleus pulposus construction because of their appropriate swelling character and ability of inducing cells to secrete nucleus pulposus matrix. Silk fibroin, collagen, polyethylene glycol, polylactic acid, polyglycolic acid and polycaprolactone with high mechanical strength are suitable for annulus fibrosus construction to bear high loading burden. By further surface modification, these synthesis scaffolds wound show a better cellular compatibility and promote tissue integrity after in vivo implantation.

Research progress of intervertebral disc repair with decellularized matrix materials / 中国组织工程研究

BACKGROUND: With the development of tissue engineering, the repair and regeneration of disc becomes possible. Decellularized extracellular matrix is an important means for disc regeneration. OBJECTIVE: To review and summarize the processing, quality control and application of decellularized matrix materials applied in intervertebral disc regeneration in recent years and put forward the prospect. METHODS: PubMed, Web of Science and CNKI databases were searched for the articles concerning decellularized methods and decellularized matrix repairing intervertebral disc with the search terms of “intervertebral disc, decellularization, extracellular matrix, scaffold material, tissue engineering” in English and Chinese, respectively. After screening based on the inclusion and exclusion criteria, the articles with high relevance were included for review. RESULTS AND CONCLUSION: The decellularized tissue-engineered intervertebral disc aims to maintain the physiologically relevant bioactivators to a great extent, improve mechanical properties and biocompatibility, and reduce immunogenicity. The decellularized matrix material can simulate the microenvironment of the extracellular matrix in the intervertebral disc. As a cell carrier, it can well induce the differentiation of seed cells, which has achieved certain progress in the repair of intervertebral discs. However, further studies need to address the following issues: proper porosity of decellularized matrix materials, immunological rejection, implant ways in vivo and repair effect.

P38/akt pathway regulates the oriented differentiation of bone marrow mesenchymal stem cells in nanofiber annulus fibrosus scaffolds with different spatial structures / 中国组织工程研究

BACKGROUND: Previous studies have shown that a variety of materials can be used for the construction of tissue engineering scaffolds. The topological structure of the scaffold surface has a regulatory effect on the biological behaviors such as stem cell proliferation and differentiation, but the specific mechanism is still unclear. OBJECTIVE: To investigate the role of P38 and Akt pathways in the oriented differentiation of bone marrow mesenchymal stem cells in nanofiber scaffolds. METHODS: Three kinds of nanofiber scaffolds (AFS, AYS, 3-DPS) with different structures were constructed. Rat bone marrow mesenchymal stem cells were inoculated on the surface of three kinds of nanofiber scaffolds. After osteogenic induction, cell morphology, adhesion and proliferation were detected. mRNA expression levels of key phenotype molecules (COLIα1, COLIIα1, Aggrecan, Sox-9) were measured using qRT-PCR. Intracellular P38, AKT, ERK1/2 and JNK expression was detected by western blot assay. RESULTS AND CONCLUSION: After 4 and 8 hours of culture, cell adhesion rate of the 13-DPS scaffold group was higher than that of the AFS and AYS scaffold groups (P<0.05). After 7 days of culture, cells of the 13-DPS scaffold group proliferated faster than those of AFS and AYS scaffold groups (P<0.05). Bone marrow mesenchymal stem cells adhered firmly and grew well on three kinds of scaffolds. Fibroblast-like growth was observed on the AFS and AYS scaffolds and chondrocyte-like growth was observed on the 3-DPS scaffold. After 3 weeks of cartilage induction, mRNA expression of COLIIα1, Aggrecan and Sox-9 was higher, and the mRNA expression of COLIα1 was lower, in the 3-DPS scaffold group compared with the other two groups (both P<0.05). After 3 weeks of cartilage induction, relative expression level of p-AKT and p-P38 in the 3-DPS scaffold group was significantly higher than that in the other two groups (both P<0.05). There were no significant differences in AKT total protein and ERK1/2, JNK, P38, p-ERK1/2, p-JNK and p-P38 protein expression levels among three groups. These findings suggest that nanofiber annulus fibrosus scaffolds with different spatial structures can induce the oriented differentiation of bone marrow mesenchymal stem cells through the P38 and AKT pathway, which were the downstream of the Integrin-FAK signaling pathway.

Biomechanical characteristics of the lumbar disc after fatigue injury / 中国组织工程研究

BACKGROUND: Lumbar disc herniation is a common clinical disease, and its pathological basis is disc degeneration. Long-term mechanical load is considered to be an important cause of lumbar disc degeneration. Because the occurrence of lumbar disc herniation is strongly associated with its mechanical state, it is necessary to further study the stress/strain behavior in the lumbar disc to provide inspiration for preventing lumbar disc herniation. OBJECTIVE: To analyze the effect of fatigue loading on mechanical properties of the whole and different regions of the intervertebral disc. METHODS: The freshly slaughtered sheep lumbar intervertebral discs L1-L2, L3-L4, and L5-L6 were obtained and made into experimental samples. The experimental samples were fixed on the experimental platform through the upper and lower vertebrae, and a quasi-static compression-cyclic loading compression-quasi-static compression experiment was performed. The L3-L4 motion segment was cut parallel to the sagittal plane, and the non-contact digital image correlation technique was used to record the internal deformation of the lumbar disc during compression. RESULTS AND CONCLUSION: (1) The results showed that all lumbar intervertebral discs exhibited non-linear load-displacement and stress-strain characteristics. (2) Effect of fatigue loading: The Young’s modulus of the lumbar intervertebral disc increased significantly after fatigue loading. (3) Impact of segment changes: The Young’s modulus changed with segment changes as follows: L5-L6 segments < L3-L4 segments < L1-L2 segments. (3) Effect of loading rate: Comparing the mechanical properties under the compression rate of 0.01 mm/s and 0.1 mm/s, it could be seen that with the increase of the compression rate, the Young’s modulus of the intervertebral disc increased significantly. (5) Internal displacement distribution: Fatigue loading had a significant effect on the internal displacement distribution of the lumbar disc under compression. Before fatigue loading, the axial displacement in upper afferent fiber was largest, and the radial displacement in inner afferent fiber was slightly smaller than that in outer afferent fiber. After fatigue loading, the axial displacement in upper afferent fiber was smallest, and the radial displacement in inner afferent fiber was significantly smaller than in outer afferent fiber. (6) The research work in this article has important theoretical guiding significance for preventing lumbar disc herniation in daily life.

Efficacy of transforaminal laser annuloplasty versus intradiscal radiofrequency annuloplasty for discogenic low back pain

BACKGROUND: Discogenic pain is a common cause of disability and is assumed to be a major cause of non-specific low back pain. Various treatment methods have been used for the treatment of discogenic pain. This study was conducted to compare the therapeutic success of radiofrequency (an intradiscal procedure) and laser annuloplasty (both an intradiscal and extradiscal procedure). METHODS: This single-center study included 80 patients and followed them for 6 months. Transforaminal laser annuloplasty (TFLA, 37 patients) or intradiscal radiofrequency annuloplasty (IDRA, 43 patients) was performed. The main outcomes included pain scores, determined by the numeric rating scale (NRS), and Oswestry disability index (ODI), at pre-treatment and at post-treatment months 1 and 6. RESULTS: The patients were grouped according to procedure. In all procedures, NRS and ODI scores were significantly decreased over time. Mean post-treatment pain scores at months 1 and 6 were significantly lower (P 40%. CONCLUSIONS: Our results indicate that annuloplasty is a reasonable treatment option for carefully selected patients with lower back and radicular pain of discogenic origin, and TFLA might be superior to IDRA in patients with discogenic low back pain.

Quantitative Predictive Imaging Biomarkers of Lumbar Intervertebral Disc Degeneration

STUDY DESIGN: Observational comparative study. PURPOSE: To compare fractional anisotropy (FA) maps with T2 values of the nucleus pulposus (NP) and annulus fibrosus (AF) of intervertebral discs in healthy volunteers and patients to develop a predictive disc health scale. OVERVIEW OF LITERATURE: T2-weighted magnetic resonance imaging (MRI) is not sensitive to early morphological changes and provides no quantitative biomarker profile for early degeneration. METHODS: We examined 59 healthy controls and 59 patients with back pain by MRI using T2 relaxometry and diffusion tensor imaging (DTI). Each group was divided into three age subgroups: A (50 years, n=21). We obtained FA values for AF and NP and T2 values for NP for each intervertebral disc. Furthermore, we calculated the FA (AF/NP) ratios. RESULTS: We categorized 590 intervertebral discs from 118 participants, 566 of which were analyzed with T2 relaxometry and DTI. The T2 values were as follows: subgroup A, 55.8±4.4 ms; B, 48.5±6.9 ms; C, 45.8±8.7 ms (p120 ms, 90–100 ms, and 70 ms, respectively (p<0.001). Control subgroup A had higher T2 values and AF/NP ratios than subgroups B and C; the AF values were not significantly different. Control subgroup B had higher T2 values and AF/NP ratios than subgroup C but lower FA (NP). CONCLUSIONS: FA maps of the AF/NP ratio and T2 values of NP are potential microstructure biomarkers of normal and degenerating discs and can help detect early degeneration using a predictive disc health score on a continuous scale.

Energy supply and demand in the intervertebral disc / Fornecimento e demanda de energia no disco intervertebral / Suministro de energía y demanda en el disco intervertebral

ABSTRACT The intervertebral disc (IVD) is one of the parts of the body most commonly affected by disease, and it is only recently that we have come closer to understanding the reasons for its degeneration, in which nutrient supply plays a crucial role. In this literature review, we discuss the basic principles and characteristics of energy supply and demand to the IVD. Specifically, we review how different metabolites influence IVD cell activity, the effects of mechanical loading on IVD cell metabolism, and differences in energy metabolism of the annulus fibrous and nucleus pulposus cell phenotypes. Determining the factors that influence nutrient supply and demand in the IVD will enhance our understanding of the IVD pathology, and help to elucidate new therapeutic targets for IVD degeneration treatment.

RESUMO O disco intervertebral (IVD) é uma das partes mais comuns do corpo e apenas recentemente nos aproximamos de compreender as razões da sua degeneração, em que o suprimento de nutrientes desempenha um papel crucial. Nesta revisão da literatura, discutimos os princípios básicos e as nuances do fornecimento e da demanda de energia para o IVD. Específicamente, analisamos como os diferentes metabólitos influenciam na atividade das células IVD, os efeitos da carga mecânica no metabolismo das células IVD, a diferença no metabolismo energético dos fenótipos das células fibrosas e do núcleo do pulposus anelar. A determinação de fatores que influenciam o suprimento e a demanda de nutrientes no IVD aumentará nossa compreensão da patologia IVD e ajudará a elucidar novos alvos terapêuticos para o tratamento da degeneração IVD.

RESUMEN El disco intervertebral (IVD, por sus siglas en inglés) es una de las partes más comúnmente enfermas del cuerpo y solo recientemente nos acercamos a la comprensión de los motivos de su degeneración, de los cuales el suministro de nutrientes juega un papel crucial. En esta revisión de la literatura discutimos los principios básicos y los matices de la oferta y demanda de energía para el IVD. Específicamente, revisamos cómo los diferentes metabolitos influyen en la actividad de las células IVD, los efectos de la carga mecánica sobre el metabolismo de las células IVD y las diferencias en el metabolismo energético de los fenotipos de las células del anillo fibroso y el núcleo pulposo. La determinación de los factores que influyen en la oferta y demanda de nutrientes en el IVD mejorará nuestra comprensión de la patología IVD y ayudará a dilucidar nuevos objetivos terapéuticos para el tratamiento de la degeneración IVD.

Outcomes of surgical treatment of lumbar disk herniation using an annular closure device / Desfechos do tratamento cirúrgico da hérnia de disco lombar com aparelho de fechamento anular / Resultados del tratamiento quirúrgico de la hernia de disco lumbar utilizando un dispositivo de cierre anular

ABSTRACT Objective: The aim of the study was to investigate the clinical and radiological results of using the annular closure device in patients with lumbar disc herniation (LDH). Methods: The study involved 120 patients with LDH operated on by limited discectomy and annular closure using the Barricaid device. A literature review was conducted to evaluate the effectiveness of the annuloplasty. Results: All patients showed postoperative regression of the radicular pain syndrome and were mobilized on the day of surgery. The correlation between the removed nucleus pulposus and changes in DHI was studied by linear regression. The results revealed that disc height loss is directly correlated with the volume of removed nucleus pulposus (p <0.05). Modic changes were present in 22 (22%) patients. Endplate changes (resorption and erosion) were present in 25 patients (20.7%). We found that these changes in MR and CT images have no effect on the clinical presentation of the disease. No intraoperative complications, such as severe hemorrhage requiring blood transfusion, or injury to the dura mater or nerve roots, were observed in our case series. Postoperative complications occurred in 3 (2.5%) patients. The reoperation rate was 4.2%. Conclusions: The use of the Barricaid annular closure device in 120 patients with lumbar disc herniation and high risk of recurrent herniation showed good clinical and radiographic outcomes. The reoperation rate in our study was 2.5%; disc reherniation at the operated level was observed in 1.7% of patients. This is a good outcome compared to the data reported for patients having a high risk of disc reherniation. Level of Evidence IV; Case series.

RESUMO Objetivo: O objetivo do estudo foi estudar os resultados clínicos e radiológicos do uso do dispositivo de fechamento anular em pacientes com hérnia discal lombar (HDL). Métodos: O estudo envolveu 120 pacientes com LDH operados por discectomia limitada e fechamento anular usando o dispositivo Barricaid. Uma revisão da literatura foi realizada para avaliar a eficácia da anuloplastia. Resultados: Todos os pacientes apresentaram regressão pós-operatória da síndrome da dor radicular e foram mobilizados no dia da cirurgia. A correlação entre o núcleo pulposo removido e as alterações no DHI foi estudada por regressão linear. Revelou-se que a perda de altura discal está diretamente correlacionada com o volume do núcleo pulposo removido (p <0,05). Alterações modicadas reveladas em 22 (22%) pacientes. As alterações no endplate foram reveladas em 25 pacientes (20,7%). Descobrimos que essas mudanças nas imagens de RM e TC não têm efeito sobre a apresentação clínica da doença. Não foram observadas complicações intraoperatórias, como hemorragia grave que necessitou de transfusão sanguínea, lesão da dura-máter ou raízes nervosas, em nossa casuística. Complicações pós-operatórias foram reveladas em 3 (2,5%) pacientes. A taxa de reoperação foi de 4,2%. Conclusão: O uso do dispositivo de fechamento anular Barricaid em 120 pacientes com hérnia discal lombar e alto risco de hérnia recorrente mostrou bons resultados clínicos e radiográficos. A taxa de reoperação em nosso estudo foi de 2,5%; reinteriato discal no nível operado foi observado em 1,7% dos pacientes. É um bom resultado comparado aos dados relatados para pacientes com alto risco de reintervenção com disco. Nível de evidência IV; Série de casos.

RESUMEN Objetivo: El objetivo del estudio fue estudiar los resultados clínicos y radiológicos del uso del dispositivo de cierre anular en pacientes con hernia de disco lumbar (LDH). Métodos: El estudio involucró a 120 pacientes con LDH operados por discectomía limitada y cierre anular usando el dispositivo Barricaid. Se realizó una revisión de la literatura para evaluar la efectividad de la anuloplastia. Resultados: Todos los pacientes mostraron regresión postoperatoria del síndrome de dolor radicular y se movilizaron el día de la cirugía. La correlación entre el núcleo pulposo retirado y los cambios en DHI se estudiaron mediante regresión lineal. Los resultados revelaron que la pérdida de altura del disco se correlaciona directamente con el volumen del núcleo pulposo retirado (p <0,05). Cambios módicos revelados en 22 (22%) pacientes. Los cambios de placa terminal (resorción y erosión) se revelaron en 25 pacientes (20,7%). Descubrimos que estos cambios en las imágenes de RM y TC no tienen ningún efecto sobre la presentación clínica de la enfermedad. En nuestra serie de casos no se observaron complicaciones intraoperatorias, como hemorragia severa que requiriera transfusión de sangre, lesión de la duramadre o raíces nerviosas. Las complicaciones postoperatorias se revelaron en 3 (2,5%) pacientes. La tasa de reoperación fue del 4,2%. Conclusiones: El uso del dispositivo de cierre anular Barricaid en 120 pacientes con hernia de disco lumbar y alto riesgo de hernia recurrente mostró buenos resultados clínicos y radiográficos. La tasa de reoperación en nuestro estudio fue del 2.5%; la hernia recurrente del disco en el nivel operado se observó en el 1,7% de pacientes. Es un buen resultado en comparación con los datos informados para pacientes que tienen un alto riesgo de hernia recurrente del disco. Nivel de evidencia IV; Serie de casos.

Treatment of Targeted Percutanous Ozone Ablation on Lumbar Disc Herniation with High Intensity Zone in Lumbar Disc Annulus Fibrosus / 现代生物医学进展

Objective:To observe the clinical effects of targeted percutanous ozone ablation on lumbar disc herniation (LDH) patients with high intensity zone (HIZ) in lumbar disc annulus fibrosus on MRI T2 weighted imaging.Methods:136 LDH patients with HIZ in lumbar disc annulus fibrosus on MRI T2 were divided into two groups according to therapy methods.In group A,75 patients were injected with 2 ～5 mL of 40 μg/mL mixture of O3 and O2 after targeted percutanous puncturing under the guidance of X-Ray machine with C-type arm.In group B,61 patients were treated with conservative treatment.MacNab score criterion and Oswestry disability index (ODI) were used in assessment of the efficacy.Results:Except 24 patients,all the other cases were followed up for 18 ～ 44 months.At the postoperative 1st,2nd,3rd,6th,9th,12th and 18th month,according to MacNab score criterion,the effective rates were respectively 88.00 ％,90.67 ％,93.33 ％,89.39 ％,84.85 ％,78.13 ％ and 73.44 ％ in group A and respectively 68.85 ％,62.30 ％ 55.74 ％,61.82 ％,58.12 ％,54.17 ％ and 47.92 ％ in group B.There were significant differences between two groups at the same time point (P＜0.05).At the postoperative 12th and 18th month,ODI was lower in group A,and there was no significant difference between two time points (P＞0.05).But it was significant different with that preoperatively and in group B at the same time point (P＜0.05).Conclusion:Targeted percutanous ozone ablation is an effective method with stable clinical efficacy in treating LDH with HIZ in lumbar disc annulus fibrosus on MRI T2 weighted imaging.

Expression and significance of MMP-1 and TIMP-1 in the nucleus pulposus and anulus fibrosus of intervertebral disc with different lesions / 局解手术学杂志

Objective To explore the expression and significance of MMP-1 and TIMP-1 in the nucleus pulposus and anulus fibrosus of intervertebral disc with different lesions.Methods From August 2014 to August 2016,34 cases of lumbar disc herniation (the observation group) and 34 case of surgical removal of intervertebral disc in patients with vertebral trauma caused by sudden trauma (the control group) in our hospital were stuided.The nucleus pulposus and anulus fibrosus of intervertebral disc were separated,and the expression of MMP-1 and TIMP-1 were detected by immunohistochemistry.The relationship between MMP-1 and TIMP-1 expression and intervertebral disc degeneration was analyzed.Results The MMP-1 and TIMP-1 expression of nucleus pulposus in the observation group were significantly higher than those in the control group(P>0.05);and the MMP-1 and TIMP-1 expression of nucleus pulposus decreased successively in prominent type,extrusion type,free type lumbar intervertebral disc degeneration(P0.05);and the MMP-1 and TIMP-1 expression of anulus fibrosus decreased successively in prominent type,extrusion type,free type lumbar intervertebral disc degeneration(P<0.05).Patients with high expression of MMP-1 and TIMP-1 in nucleus pulposus and anulus fibrosus had more risk of degenerative disc disease(P<0.05).As a sensitivity prediction of intervertebral disc degeneration,the sensitivity of MMP-1 was 82.35% while the specificity was 94.11%,and the sensitivity of TIMP-1 was 79.41% while the specificity was 88.24%.The prediction sensitivity of intervertebral disc degeneration was 90.91% and the specificity was 97.14% when combined MMP-1 with TIMP-1.Conclusion The expression of MMP-1 and TIMP-1 in the nucleus pulposus and anulus fibrosus of intervertebral disc degeneration was significantly increased,which is of great clinical significance in the diagnosis of intervertebral disc degeneration.

Tissue Engineering of the Intervertebral Disc's Annulus Fibrosus: A Scaffold-Based Review Study

Tissue engineering as a high technology solution for treating disc's problem has been the focus of some researches recently; however, the upcoming successful results in this area depends on understanding the complexities of biology and engineering interface. Whereas the major responsibility of the nucleus pulposus is to provide a sustainable hydrated environment within the disc, the function of the annulus fibrosus (AF) is more mechanical, facilitating joint mobility and preventing radial bulging by confining of the central part, which makes the AF reconstruction important. Although the body of knowledge regarding the AF tissue engineering has grown rapidly, the opportunities to improve current understanding of how artificial scaffolds are able to mimic the AF concentric structure—including inter-lamellar matrix and cross-bridges—addressed unresolved research questions. The aim of this literature review was to collect and discuss, from the international scientific literature, information about tissue engineering of the AF based on scaffold fabrication and material properties, useful for developing new strategies in disc tissue engineering. The key parameter of this research was understanding if role of cross-bridges and inter-lamellar matrix has been considered on tissue engineering of the AF.

Establishment of annulus fibrosus partial defect model in sheep / 天津医药

Objective To establish an animal model of annulus fibrosus (AF) partial defect for the repairing of interver?tebral disc (IVD) defect. Methods Image J 1.46r software was used to measure the T12/L1-L6/S1 intervertebral height in ovine lumbar spine X-ray films. AF thickness was measured by axial split disc. A 11 blade was used to make a trapezoid de?fect of upper bottom 3 mm, lower bottom 5 mm, height 5 mm and thickness 3 mm, whose lower bottom toward the nucleus pulposus (NP) in the left front of ovine lumbar IVD in vitro. The minimally invasive lateral approach was used to make the same type of trapezoid defect in the left front of the ovine lumbar IVD in vivo. The trapezoidal defect length of the axial divid?ing disc was measured, AF and a small amount of NP from trapezoidal defect in IVD were weighed, and the production of trapezoidal defect in IVD was evaluated. Results The lumbar intervertebral space height of ovine was (4.45 ± 0.28) mm. There were significant differences in the thickness of AF (4.08±0.50) mm , thickness (3 mm) and height (5 mm) of trapezoidal defect (P0. 05). The weights of the AF and NP taken out from ovine lumbar IVD in vitro and in vivo were (0.162 ± 0.011) g and (0.166 ± 0.014) g, and there was no significant difference between them (P > 0.05). Conclusion Through the operation of minimally invasive lateral approach, the method of making a trapezoidal defect in the experiments can establish animal model of AF partial defect, which meets the requirements for the repairing of IVD defect, and is simple, safe and reliable.

Repair Using Conventional Implant for Ruptured Annulus Fibrosus after Lumbar Discectomy: Surgical Technique and Case Series

STUDY DESIGN: A retrospective review of annulus fibrosus repair (AR) using a novel technique with a conventional implant. PURPOSE: The purpose of this study was to present the feasibility and clinico-radiological outcomes of a novel AR technique using a conventional implant to minimize recurrence following a lumbar discectomy (LD). OVERVIEW OF LITERATURE: Conventional repair techniques to prevent recurrence following LD have several drawbacks. The AR surgical technique has received little attention as an adjunct to LD. METHODS: A total of 19 patients who underwent novel AR following LD, and who were available for follow-up for at least three years, were enrolled in this study. Several variables, including the type and size of disc herniation, and the degree of disc degeneration, were evaluated preoperatively. Postoperatively, the presence of clinical and radiological recurrence of disc herniation was evaluated from pain intensity and functional statuses, as well as an enhanced L-spine magnetic resonance imaging at the final follow-up. The presence of a peripheral hollow rim and inserted anchor mobilization were also evaluated during the follow-up. RESULTS: During follow-ups, there were no recurrences of disc herniation or complications, including neurovascular complications. Pain and functional disability improved significantly after surgery, and the improvement was maintained throughout the three-year follow-up period. No mobilization or implant peripheral hollow rim was observed during the follow-up. CONCLUSIONS: This study examined the feasibility of a novel and easily available annulus implant technique following LD. These results suggest performing AR with this technique may be a valuable alternative for optimizing outcomes, if the procedure is performed in proper candidates.

Manufacture and evaluation of integrated biphasic silk fibroin scaffold made by annulus fibrosus-nucleus pulposus tissue engineering / 天津医药

Objective To assess the prospect of integrated biphasic silk fibroin scaffold made by annulus fibrosus-nu?cleus pulposus tissue engineering in application as integrated intervertebral disc(IVD). Methods An integrated annulus fi brosus-nucleus pulposus(AF-NP)biphasic scaffold was made by silk fi broin using two different uncomplicated methods which were paraffin spheres-leaching method(outer AF phase)and phase separation method(inner NP phase). The scaf?fold was investigated by general observation, stereomicroscope and scanning electron microscopy(SEM). Its pore size, poros?ity, and compressive elastic modulus were determined. AF and NP cells were isolated from rabbit IVD and seeded into the corresponding phase of the scaffold respectively. The cell-scaffold complex was cultured for 48 hours. The biocompatibility of the scaffold was evaluated by SEM, live/dead staining while CCK-8 assay was used to assess cell proliferation. Results Stereomicroscope and SEM showed that AF phase and NP phase integrated perfectly without cross-linking. Both phases pos?sessed highly interconnected porous structure [pore size of AF and NP phase were(220.0±23.1)μm and(90.0±17.8)μm, re?spectively] and highly porosity(AF and NP phase were respectively 91%and 93%). In addition, this silk biphasic scaffold had impressive mechanical properties(150.7 ± 6.8)kPa. SEM revealed that disc cells attached to regions of pore walls, dis?tributed uniformly and secreted extracellular matrix. Live/Dead staining and cell count kit-8(CCK-8)analysis showed that the silk composite scaffold was non-cytotoxic to disc cells. Conclusion This silk biphasic AF-NP scaffold has satisfied pore size, porosity, biomechanical properties and biocompatibility, so it is ideal candidate for IVD tissue engineering.