M2 Macrophage-Derived Small Extracellular Vesicles Ameliorate Pyroptosis and Intervertebral Disc Degeneration.

Intervertebral discs (IVDs) have a limited self-regenerative capacity and current strategies for IVD regeneration are unsatisfactory. Recent studies showed that small extracellular vesicles derived from M2 macrophage cells (M2-sEVs) inhibited inflammation by delivery of various bioactive molecules to recipient cells, which indicated that M2-sEVs may offer a therapeutic strategy for the repair of IVDs. Herein, we investigated the roles and mechanisms of M2-sEVs on IVD regeneration. The in vitro results demonstrated that M2-sEVs inhibited pyroptosis, preserved cellular viability, and promoted migration of nucleus pulposus cells (NPCs). Bioinformatics analysis and verification experiments of microRNA (miR) expression showed that miR-221-3p was highly expressed in M2-sEVs. The mechanism of action was explored and indicated that M2-sEVs inhibited pyroptosis of NPCs through transfer of miR-221-3p, which suppressed the expression levels of phosphatase and tensin homolog and NOD-, LRR-, and pyrin domain-containing protein 3. Moreover, we fabricated decellularized ECM-hydrogel (dECM) for sustained release of M2-sEVs, which exhibited biocompatibility and controlled release properties. The in vivo results revealed that dECM-hydrogel containing M2-sEVs (dECM/M2-sEVs) delayed the degeneration of intervertebral disc degeneration (IDD) models. In addition to demonstrating a promising therapeutic for IDD, this study provided valuable data for furthering the understanding of the roles and mechanisms of M2-sEVs in IVD regeneration.

Radiographic characteristics-based classification system for percutaneous endoscopic lumbar discectomy surgical approach selection in patients with L5-S1 disc herniation: a hierarchical clustering analysis.

Background: No classification system exists for aiding the selection of surgical approaches in L5-S1 disc herniation when undergoing percutaneous endoscopic lumbar discectomy (PELD). We aimed to identify radiographic subtypes to aid the selection of percutaneous endoscopic transforaminal discectomy (PETD) and percutaneous endoscopic interlaminar discectomy (PEID) in patients with L5-S1 disc herniation via unsupervised hierarchical clustering analysis. Methods: In this retrospective case-control study, we gathered 296 anteroposterior and lateral lumbar spine radiographs (dataset 1) from Tianjin Hospital between January 2016 and October 2021 for clustering analyses. Additionally, we analyzed 111 patients who underwent PEID or PETD for L5-S1 disc herniation at Tianjin Hospital from January 2016 to August 2022. We included patients with radicular leg pain or back pain associated with intra-canal disc herniation who failed in conservative treatments over 6 weeks. First, pair-wise Spearman correlation coefficients were calculated among plain radiographic metrics in dataset 1 to reveal the association among these radiographic metrics. Second, hierarchical clustering analysis was conducted to unsupervised cluster the plain films into several subtypes. Last, for each radiographic subtype, the intraoperative blood loss (IBL), operation time (OT), total operating room time (TORT) along with visual analogue scale (VAS) and Oswestry Disability Index (ODI) were compared between patients underwent PETD or PEID with age as covariates. Results: This study yielded 3 main findings: (I) iliac height (IH) was negatively correlated with intervertebral foramen width (IFW), intervertebral foramen height (IFH), and intertransverse height (ITH) (R=-0.50, -0.42, and -0.46, all P<0.001), ITH was positively correlated with IFW and IFH (R=0.40 and 0.53, all P<0.001); (II) 2 lumbosacral radiographic subtypes were identified via hierarchical clustering analysis; (III) relative to subtype 1, the patients identified as subtype 2 exhibited lesser IBL, shorter OT, and shorter TORT following PETD (t=2.92, P=0.006; t=2.65, P=0.012; t=3.17, P=0.003). Conclusions: The morphology pattern of the lumbosacral region affect the ease of different PELD procedures when performing percutaneous discectomy at the segment of L5-S1. Without considering the type of disc herniation, this classification system might aid spine surgeons in the selection of an appropriate surgical approach.

Application of self-anchored lateral lumbar interbody fusion in lumbar degenerative diseases.

STUDY DESIGN: This is a retrospective study. OBJECTIVE: The aim of the study was to evaluate the efficacy of self-anchored lateral lumbar interbody fusion (SA-LLIF) in lumbar degenerative diseases. METHODS: Forty-eight patients with lumbar degenerative disease between January 2019 and June 2020 were enrolled in this study. All patients complained of low back and leg pain, which were aggravated during standing activities and alleviated or disappeared during lying. After general anesthesia, the patient was placed in the right decubitus position. The anterior edge of the psoas major muscle was exposed through an oblique incision of approximately 6 cm, using an extraperitoneal approach. The psoas major muscle was then properly retracted dorsally to expose the disc. After discectomy, a suitable cage filled with autogenous bone graft from the ilium was implanted. Two anchoring plates were inserted separately into the caudal and cranial vertebral bodies to lock the cage. Clinical efficacy was evaluated using the visual analog scale (VAS) and Oswestry Disability Index (ODI). Lumbar lordosis, intervertebral disc height, spondylolisthesis rate, cage subsidence and fusion rate were also recorded. RESULTS: A total of 48 patients were enrolled in this study, including 20 males and 28 females, aged 61.4 ± 7.3 (range 49-78) years old. Surgery was successfully performed in all patients. Lumbar stenosis and instability were observed in 22 cases, disc degenerative disease in eight cases, degenerative spondylolisthesis in nine cases, degenerative scoliosis in six cases, and postoperative revision in three cases. In addition, five patients were diagnosed with osteoporosis. The index levels included L2-3 in three patients, L3-4 in 13 patients, L4-5 in 23 patients, L2-4 in three patients, and L3-5 in six patients. The operation time was 81.1 ± 6.4 (range 65-102) min. Intraoperative blood loss was 39.9 ± 8.5 (range 15-72) mL. No severe complications occurred, such as nerve or blood vessel injuries. The patients were followed up for 11.7 ± 2.3 (range 4-18) months. At the last follow-up, the VAS decreased from 6.2 ± 2.3 to 1.7 ± 1.1, and the ODI decreased from 48.4% ± 11.2% to 10.9% ± 5.5%. Radiography showed satisfactory postoperative spine alignment. No cage displacement was found, but cage subsidence 2-3 mm was found in five patients without obvious symptoms, except transient low back pain in an obese patient. The lumbar lordosis recovered from 36.8° ± 7.9° to 47.7° ± 6.8°, and intervertebral disc height recovered from 8.2 ± 2.0 mm to 11.4 ± 2.5 mm. The spondylolisthesis rate decreased from 19.9% ± 4.9% to 9.4% ± 3.2%. The difference between preoperative and last follow-up was statistically significant (P<0.05). CONCLUSION: SA-LLIF can provide immediate stability and good results for lumbar degenerative diseases with a standalone anchored cage without posterior internal fixation.

Exploration of the Extraperitoneal Approach for Single-Level Anterior Lumbar Interbody Fusion: Imaging, Anatomical and Clinical Research.

Background: To explore extraperitoneal approach as an optimal option for reducing peritoneal disruption at a single-level disc in anterior lumbar interbody fusion (ALIF). Methods: First, abdominal axial CT images obtained from 111 patients were observed to evaluate the distribution of extraperitoneal fat at L2-S1 and measure the lateral distances between the midline and the lateral borders of the rectus and the extraperitoneal fat for each disc level. Second, eight embalmed corpses were dissected along the lateral border of the rectus to expose the peritoneum, which was then separated laterally and medially to evaluate the distribution of fat and peritoneum adhesion. Finally, a total of 58 patients were selected for ALIF. For L2-L4 discs and L4-S1, the pararectus approach and the paramedian approach were utilized, respectively. Results: Extraperitoneal fat was observed behind the rectus at the L5-S1 and the lateral distance between the fat and midline and the lateral border of the rectus gradually decreased on both sides of L2-5. On the cranial side of the arcuate line, it was easier to separate the peritoneum outward along the lateral edge of the rectus. When bluntly dissected medially, the peritoneum was closely adhered to abdominal wall. No complications such as peritoneal damage, retroperitoneal hematoma and neurological complications occurred in 58 patients undergoing the aforementioned surgical methods. Conclusions: For L4-S1, the paramedian approach is the optimal technique to expose the disc, whereas the pararectus approach is the feasible surgical method at L2-4.

Dynamic changes of enhancer and super enhancer landscape in degenerated nucleus pulposus cells.

Inflammatory cascade and extracellular matrix remodeling have been identified as pivotal pathological factors in the progression of intervertebral disc degeneration (IDD), but the mechanisms underlying the aberrant activation of transcription during nucleus pulposus (NP) cell degeneration remain elusive. Super-enhancers (SEs) are large clusters of adjacent lone enhancers, which control expression modes of cellular fate and pathogenic genes. Here, we showed that SEs underwent tremendous remodeling during NP cell degeneration and that SE-related transcripts were most abundant in inflammatory cascade and extracellular matrix remodeling processes. Inhibition of cyclin-dependent kinase 7, a transcriptional kinase-mediated transcriptional initiation in trans-acting SE complex, constricted the transcription of inflammatory cascades, and extracellular matrix remodeling-related genes such as IL1ß and MMP3 in NP cells, meanwhile, also restrained the transcription of Mmp16, Tnfrsf21, and Il11ra1 to retard IDD in rats. In summary, our findings clarify SEs control the transcription of genes associated with inflammatory cascade and extracellular matrix remodeling during NP cell degeneration and identify inhibition of the cyclin-dependent kinase 7, required for SE-mediated transcriptional activation, as a therapeutic option for IDD.

Efficacy of intradiscal injection of platelet-rich plasma in the treatment of discogenic low back pain: A single-arm meta-analysis.

BACKGROUND: Discogenic low back pain (DLBP) has been influencing people's quality of life. Research on platelet-rich plasma (PRP) for DLBP has increased in recent years, but systematic summaries are lacking. This study analyzes all published studies related to the use of intradiscal injection of PRP for the treatment of DLBP and summarizes evidence-based medicine for the efficacy of this biologic treatment for DLBP. METHODS: Articles published from the inception of the database to April 2022 were retrieved from PubMed, the Cochrane Library, Embase, ClinicalTrial, the Chinese National Knowledge Infrastructure, Wanfang, Chongqing VIP Chinese Scientific Journals, and the Chinese Biomedicine databases. After the rigorous screening of all studies on PRP for DLBP, a meta-analysis was performed. RESULTS: Six studies, including 3 randomized controlled trials and 3 prospective single-arm trials, were included. According to this meta-analysis, pain scores decreased by >30% and >50% from baseline, with incidence rates of 57.3%, 50.7%, and 65.6%, and 51.0%, 53.1%, and 51.9%, respectively, after 1, 2, and 6 months of treatment. The Oswestry Disability Index scores decreased by >30% with an incidence rate of 40.2% and by >50% with an incidence rate of 53.9% from baseline after 2 and 6 months, respectively. Pain scores decreased significantly after 1, 2, and 6 months of treatment (standardized mean difference: 1 month, -1.04, P = .02; 2 months, -1.33, P = .003; and 6 months, -1.42, P = .0008). There was no significant change (P > .05) in the pain scores and the incidence rate when pain scores decreased by >30% and >50% from baseline between 1 and 2 months, 1 and 6 months, and 2 and 6 months after treatment. No significant adverse reactions occurred in any of the 6 included studies. CONCLUSION: Intradiscal injection of PRP is effective and safe in the treatment of DLBP, and there was no significant change in the patient's pain 1, 2, and 6 months after PRP treatment. However, confirmation is required by additional high-quality studies due to the limitations of the quantity and quality of the included studies.

Research progress in decellularized extracellular matrix hydrogels for intervertebral disc degeneration.

As one of the most common clinical disorders, low back pain (LBP) influences patient quality of life and causes substantial social and economic burdens. Many factors can result in LBP, the most common of which is intervertebral disc degeneration (IDD). The progression of IDD cannot be alleviated by conservative or surgical treatments, and gene therapy, growth factor therapy, and cell therapy have their own limitations. Recently, research on the use of hydrogel biomaterials for the treatment of IDD has garnered great interest, and satisfactory treatment results have been achieved. This article describes the classification of hydrogels, the methods of decellularized extracellular matrix (dECM) production and the various types of gel formation. The current research on dECM hydrogels for the treatment of IDD is described in detail in this article. First, an overview of the material sources, decellularization methods, and gel formation methods is given. The focus is on research performed over the last three years, which mainly consists of bovine and porcine NP tissues, while for decellularization methods, combinations of several approaches are primarily used. dECM hydrogels have significantly improved mechanical properties after the polymers are cross-linked. The main effects of these gels include induction of stem cell differentiation to intervertebral disc (IVD) cells, good mechanical properties to restore IVD height after polymer cross-linking, and slow release of exosomes. Finally, the challenges and problems still faced by dECM hydrogels for the treatment of IDD are summarised, and potential solutions are proposed. This paper is the first to summarise the research on dECM hydrogels for the treatment of IDD and aims to provide a theoretical reference for subsequent studies.

[Comparative study of microscope assisted minimally invasive anterior fusion and mobile microendoscopic discectomy assisted fusion for lumbar degenerative diseases].

Objective: To investigate the effectiveness of microscope assisted anterior lumbar discectomy and fusion (ALDF) and mobile microendoscopic discectomy assisted lumbar interbody fusion (MMED-LIF) for lumbar degenerative diseases. Methods: A clinical data of 163 patients with lumbar degenerative diseases who met the criteria between January 2018 and December 2020 was retrospectively analyzed. Fifty-three cases were treated with microscope assisted ALDF (ALDF group) and 110 cases with MMED-LIF (MMED-LIF group). There was no significant difference between the two groups in terms of gender, age, disease type, surgical segments, preoperative visual analogue scale (VAS) scores of low back pain and leg pain, Oswestry disability index (ODI), intervertebral space height, lordosis angle, and spondylolisthesis rate of the patients with lumbar spondylolisthesis ( P>0.05). The operation time, intraoperative blood loss, and hospital stay of the two groups were recorded. The effectiveness was evaluated by VAS scores of low back pain and leg pain and ODI. Postoperative lumbar X-ray films were taken to observe the position of Cage and measure the intervertebral space height, lordosis angle, and spondylolisthesis rate of the patients with lumbar spondylolisthesis. Results: The operations were successfully completed in both groups. The operation time, intraoperative blood loss, and hospital stay in ALDF group were less than those in MMED-LIF group ( P<0.05). The patients in both groups were followed up 12-36 months, with an average of 24 months. The VAS scores of low back pain and leg pain and ODI after operation were lower than those before operation in the two groups, and showed a continuous downward trend, with significant differences between different time points ( P<0.05). There were significant differences between two groups in VAS score of low back pain and ODI ( P<0.05) and no significant difference in VAS score of leg pain ( P>0.05) at each time point. The improvement rates of VAS score of low back pain and ODI in ALDF group were significantly higher than those in MMED-LIF group ( t=7.187, P=0.000; t=2.716, P=0.007), but there was no significant difference in the improvement rate of VAS score of leg pain ( t=0.556, P=0.579). The postoperative lumbar X-ray films showed the significant recovery of the intervertebral space height, lordosis angle, and spondylolisthesis rate at 2 days after operation when compared with preoperation ( P<0.05), and the improvements were maintained until last follow-up ( P>0.05). The improvement rates of intervertebral space height and lordosis angle in ALDF group were significantly higher than those in MMED-LIF group ( P<0.05). There was no significant difference in the reduction rate of spondylolisthesis between the two groups ( t=1.396, P=0.167). During follow-up, there was no loosening or breakage of the implant and no displacement or sinking of the Cage. Conclusion: Under appropriate indications, microscope assisted ALDF and MMED-LIF both can achieve good results for lumbar degenerative diseases. Microscope assisted ALDF was superior to MMED-LIF in the improvement of low back pain and function and the recovery of intervertebral space height and lordosis angle.

Development of a Risk Score Model for Osteosarcoma Based on DNA Methylation-Driven Differentially Expressed Genes.

Osteosarcoma (OS) is the commonest malignant bone tumor in adolescent patients, and patients face amputation, tumor metastasis, chemotherapy resistance, and even death. We investigated the potential connection between abnormal methylation differentially expressed genes and the survival rate of osteosarcoma patients. GSE36002 and GSE12865 datasets of GEO database were utilized for abnormal methylation differentially expressed genes, followed by function and pathway enrichment analyses, the protein-protein interaction network in the STRING database, and cluster analysis in the MCODE app of Cytoscape. The RNA-seq and clinical data from the TARGET-OS project of TCGA were used for univariate and least absolute shrinkage and selection operator (LASSO) Cox regression analyses to predict the risk genes of osteosarcoma. 1191 hypermethylation-downregulated genes might function through plasma membrane, negative regulation of transcription from the RNA polymerase II promoter, and pathways, including transcriptional misregulation in cancer. 127 hypomethylation-upregulated genes were enriched in proteolysis, negative regulation of the canonical Wnt signaling pathway, and metabolic signaling pathways. The univariate Cox analysis revealed 638 genes (P < 0.01), including 50 hypermethylation-downregulated genes and 4 hypomethylation-upregulated genes, subsequently based on LASSO Cox regression analysis for 54 aberrant methylation-driven genes, and three genes (COL13A1, MXI1, and TBRG1) were selected to construct the risk score model. The three genes (COL13A1, MXI1, and TBRG1) regulated by DNA methylation were identified to relate with the outcomes of OS patients, which might provide a new insight to the pathological mechanism of osteosarcoma.

Silencing ATF3 Might Delay TBHP-Induced Intervertebral Disc Degeneration by Repressing NPC Ferroptosis, Apoptosis, and ECM Degradation.

Intervertebral disc degeneration (IDD), being the predominant root cause of lower back pain, has led to an enormous socioeconomic burden in the world. Ferroptosis is an iron-dependent nonapoptotic and nonpyroptotic programmed cell death associated with an increase in reactive oxygen species (ROS), which has been implicated in the pathogenesis of IDD. Activation transcription factor 3 (ATF3) is widely reported to promote ferroptosis and apoptosis in multiple diseases, but its roles and underlying regulatory mechanism in IDD have not been identified. FAoptosis is defined as a mixed cell death consisting of ferroptosis and apoptosis. The loss- and gain-of-function experiments demonstrated that ATF3 positively regulated tert-butyl hydroperoxide- (TBHP-) induced nucleus pulposus cell (NPC) FAoptosis, ROS production, inflammatory response, and extracellular matrix (ECM) degradation. Furthermore, silencing ATF3 ameliorated the progression of IDD in vivo, whereas its overexpression showed the opposite phenotype. Bioinformatics analysis and molecular experiments corroborated that ATF3 is a direct target of miR-874-3p, suggesting that the upregulation of ATF3 in IDD might be caused at least in part due to the downregulation of miR-874-3p in IDD, thereby relieving the inhibition of ATF3 by miR-874-3p. The findings revealed that ATF3 has the potential to be used as a promising therapeutic target against IDD.

Autologous Mesenchymal Stromal Cells Combined with Gelatin Sponge for Repair Intervertebral Disc Defect after Discectomy: A Preclinical Study in a Goat Model.

BACKGROUND: The defect of intervertebral disc (IVD) after discectomy may impair tissue healing and predispose patients to subsequent IVD degeneration, which is thought to be an important cause of recurrence. Cell-based approaches for the treatment of IVD degeneration have shown promise in preclinical studies. However, most of these therapies have not been approved for clinical use due to the risks of abnormal differentiation and microorganism contamination of the culture-expanded cells. Selective cell retention (SCR) technology is non-cultivation technique, which can avoid those preambles in cell expansion. In this study, we used a commercially available BONE GROWTH PROMOTER device (BGP, FUWOSI, Chongqing, China) to concentrate mesenchymal stromal cells (MSCs) from bone marrow aspirate (BMA) through SCR technology. METHODS: A small incision was made on the L2/3, L3/4 and L4/5 discs of goats and part of nucleus pulposus (NP) was removed to construct IVD defect model. The L2/3 disc was subjected to discectomy only (DO group), the L3/4 disc was implanted with enriched BMA-matrix (CE group), and the L4/5 disc was implanted cultured autologous bone marrow MSCs matrix (CC group). And the intact L1/2 disc served as a non-injured control (NC group). The animals were followed up for 24 weeks after operation. Spine imaging was analysis performed at 4 and 24 weeks. Histology, immunohistochemistry, gene expression and biomechanical analysis were performed to investigate the IVD morphology, content and mechanical properties at 24 weeks. RESULTS: The CE and CC groups showed a significantly smaller reduction in the disc height and T2-weighted signal intensity, and a better spinal segmental stability than DO group. Histological analysis demonstrated that CE and CC groups maintained a relatively well-preserved structure compared to the DO group. Furthermore, real-time PCR and immunohistochemistry demonstrated that aggrecan and type II collagen were up-regulated in CE and CC groups compared to DO group. CONCLUSIONS: The strategy of MSCs enrichment combined with gelatin sponge by SCR technology provides a rapid, simple, and effective method for cell concentration and cell-carrier combination. This reparative strategy can be used in clinical treatment of IVD defect after discectomy. CLINICAL TRIAL REGISTRATION: NCT03002207.

The Roles of circRNAs in Intervertebral Disc Degeneration: Inflammation, Extracellular Matrix Metabolism, and Apoptosis.

Low back pain (LBP) is seriously harmful to human health and produces heavy economic burden. And most scholars hold that intervertebral disc degeneration (IDD) is the primary cause of LBP. With the study of IDD, aberrant expression of gene has become an important pathogenic factor of IDD. Circular RNAs (circRNAs), as a kind of noncoding RNA (ncRNA), participate in the regulation of genetic transcription and translation and further affect the expression of inflammatory cytokine, metabolism of extracellular matrix (ECM), the proliferation and apoptosis of cells, etc. Therefore, maybe it will become a new therapeutic target for IDD. At present, our understanding of the mechanism of circRNAs in IDD is limited. The purpose of this review is to summarize the mechanism and related signaling pathways of circRNAs in IDD reported in the past. Particularly, the roles of circRNAs in inflammation, ECM metabolism, and apoptosis are emphasized.

Circ_0004354 might compete with circ_0040039 to induce NPCs death and inflammatory response by targeting miR-345-3p-FAF1/TP73 axis in intervertebral disc degeneration.

The abnormal function of nucleus pulposus cells (NPCs) plays a crucial role in the pathogenesis of intervertebral disc degeneration (IVDD). Recent studies have demonstrated that circular RNAs (circRNAs) are involved in the pathological process of IVDD by regulating NPCs' function. Nevertheless, the investigation on circRNA-circRNA interaction has not yet been reported. Here, we identified the top upregulated circ_0040039 and circ_0004354 in IVDD, derived from the syntrophin beta 2 gene but had different degrees of biological functions. Accumulating studies have reported PANoptosis is composed of apoptosis, pyroptosis, and necroptosis. Based on this, we think there should be a new pro-inflammatory cell death PAoptosis in the form of apoptosis and pyroptosis. Circ_0004354 might compete with circ_0040039 to induce the development of IVDD by modulating miR-345-3p-FAF1/TP73 axis-mediated PAoptosis, inflammatory response, growth inhibition, and ECM degradation of NPCs. Thus, these findings offer a novel insight into the circRNAs-mediated posttranscriptional regulatory network in IVDD, contributing to further clarification of the pathological mechanism of IVDD to develop a promising therapeutic target for IVDD diseases.

Identification of aberrantly methylated-differentially expressed genes and potential agents for Ewing sarcoma.

BACKGROUND: Human DNA methylation is a common epigenetic regulatory mechanism, and it plays a critical role in various diseases. However, the potential role of DNA methylation in Ewing sarcoma (ES) is not clear. This study aimed to explore the regulatory roles of DNA methylation in ES. METHODS: The microarray data of gene expression and methylation were downloaded from the Gene Expression Omnibus (GEO) database, and analyzed via GEO2R. Venn analysis was then applied to identify aberrantly methylated-differentially expressed genes (DEGs). Subsequently, function and pathway enrichment analysis was conducted, a protein-protein interaction (PPI) network was constructed, and hub genes were determined. Besides, a connectivity map (CMap) analysis was performed to screen bioactive compounds for ES treatment. RESULTS: A total of 135 hypomethylated high expression genes and 523 hypermethylated low expression genes were identified. The hypomethylated high expression genes were enriched in signal transduction and the apoptosis process. Meanwhile, hypermethylated low expression genes were related to DNA replication and transcription regulation. The PPI network analysis indicated C3, TF, and TCEB1 might serve as diagnostic and therapeutic targets of ES. Furthermore, CMap analysis revealed 6 chemicals as potential options for ES treatment. CONCLUSIONS: The introduction of DNA methylation characteristics over DEGs is helpful to understand the pathogenesis of ES. The identified hub aberrantly methylated DEGs and chemicals might provide some novel insights on ES treatment.

Construction of a Potentially Functional circRNA-miRNA-mRNA Network in Intervertebral Disc Degeneration by Bioinformatics Analysis.

BACKGROUND: The competing endogenous RNA- (ceRNA-) mediated regulatory mechanisms are known to play a pivotal role in intervertebral disc degeneration (IDD). Our research intended to establish a ceRNA regulatory network related to IDD through bioinformatics analyses. METHODS: The expression profiles of circRNA, miRNA, and mRNA were obtained from the public Gene Expression Omnibus (GEO) datasets. Then, we use sequence-based bioinformatics methods to select differentially expressed mRNAs (DEmRNAs), microRNAs (DEmiRNAs), or circRNAs (DEcircRNAs) related to IDD. We used ChEA3 to verify the targets of transcription factors (TFs). Then, we used DAVID to annotate the DEmRNAs. Finally, we constructed a potentially circRNA-miRNA-mRNA network related to IDD by predicting in the database (ENCORI, TargetScan, miRecords, miRmap, and circBank). RESULTS: We identified 31 common DEmRNAs by Venn analysis, of which MMP2 was regarded as the key hub genes. Simultaneously, miR-423-5p and miR-185-5p were predicted as the upstream molecules of MMP2. Furthermore, a total of six DEcircRNAs were predicted as the upstream circRNAs of miR-423-5p and miR-185-5p. Then, a potential circRNA-miRNA-mRNA network related to IDD was constructed by bioinformatics analysis. CONCLUSION: A comprehensive ceRNA regulatory network was constructed, which was found to be significant in IDD progression.

Selective Retention of Bone Marrow Stromal Cells with Gelatin Sponge for Repair of Intervertebral Disc Defects after Microendoscopic Discectomy: A Prospective Controlled Study and 2-Year Follow-Up.

OBJECTIVE: Discectomy remains the classic procedure for treating lumbar intervertebral disc (IVD) herniation, but the occurrence of defects after discectomy is thought to be an important cause generating recurrent and accelerated IVD degeneration. Previous studies attempted suture of the annulus fissure, but the validity of this technique on restraining the degenerative process is controversial. On the other hand, cell therapies have been shown in multiple clinical and basic studies. Our purpose was to investigate the effectiveness of selective retention of autologous Bone Marrow Stromal Cells (BMSCs) with gelatin sponge in combination with annulus fibrosus suture (AFS) for the repair of IVD defects following mobile microendoscopic discectomy (MMED). METHODS: This prospective, two-armed, and controlled clinical study was conducted from December 2016 to December 2018. Written informed consent was obtained from each patient. Forty-five patients with typical symptoms, positive signs of radiculopathy, and obvious lumbar disc herniation observed by MRI were enrolled. Patients were divided into 3 groups with different treating methods: MMED (n = 15), MMED+AFS (n = 15), and MMED+AFS+BMSCs (n = 15). A postoperative 2-year follow-up was performed to evaluate the patient-reported outcomes of VAS, ODI, and SF-36. The improvement rate of VAS and ODI was calculated as [(latest-preoperative)/preoperative] to evaluate the therapeutic effect of the three groups. Assessment parameters included Pfirrmann grade, intervertebral disc height (IDH), and disc protrusion size (DPS), as measured by MRI to evaluate the morphological changes. RESULTS: All patients enrolled had a postoperative follow-up at 3, 6, 12, and 24 months. VAS and ODI scores were significantly improved compared to the preoperative status in all three groups with a mean DPS reduction rate over 50%. At the final follow-up, the improvement rate of the VAS score in the MMED+AFS+BMSCs group was significantly higher than the MMED+AFS and MMED groups (80.1% ± 7.6% vs. 71.3% ± 7.0% vs. 70.1% ± 7.8%), while ODI improvement showed a significant change (65.6% ± 8.8% vs. 59.9% ± 5.5% vs. 57.8% ± 8.1%). All participants showed significant improvement in SF-36 PCS and MCS; the differences between each group were not significant. The mean IDH loss rate of the MMED+AFS+BMSCs group was also significantly lower than other groups (-17.2% ± 1.3% vs. -27.6% ± 0.7% vs. -29.3% ± 2.2%). The Pfirrmann grade was aggravated in the MMED and MMED+AFS groups while maintained at the preoperative grade in the MMED+AFS+BMSCs group. No adverse events of cell transplantation or recurrence were found in all patients during the postoperative follow-up period. CONCLUSIONS: It is feasible and effective to repair lumbar IVD defects using SCR-enriched BMSCs with gelatin sponges, which warrants further study and development as a cell-based therapy for IVD repair.

Construction of chitosan scaffolds with controllable microchannel for tissue engineering and regenerative medicine.

Microchannels are effective means of enabling the functional performance of tissue engineering scaffolds. Chitosan, a partial deacetylation derivative of chitin, exhibiting excellent biocompatibility, has been widely used in clinical practice. However, development of chitosan scaffolds with controllable microchannels architecture remains an engineering challenge. Here, we generated chitosan scaffolds with adjustable microchannel by combining a 3D printing microfiber templates-leaching method and a freeze-drying method. We can precisely control the arrangement, diameter and density of microchannel within chitosan scaffolds. Moreover, the integrated bilayer scaffolds with the desired structural parameters in each layer were fabricated and exhibited no delamination. The flow rate and volume of the simulated fluid can be modulated by diverse channels architecture. Additionally, the microchannel structure promoted cell survival, proliferation and distribution in vitro, and improved cell and tissue ingrowth and vascular formation in vivo. This study opens a new road for constructing chitosan scaffolds, and can further extend their application scope across tissue engineering and regenerative medicine.

Circ_0040039 May Aggravate Intervertebral Disk Degeneration by Regulating the MiR-874-3p-ESR1 Pathway.

The functional alteration of nucleus pulposus cells (NPCs) exerts a crucial role in the occurrence and progression of intervertebral disk degeneration (IDD). Circular RNAs and microRNAs (miRs) are critical regulators of NPC metabolic processes such as growth and apoptosis. In this study, bioinformatics tools, encompassing Gene Ontology pathway and Venn diagrams analysis, and protein-protein interaction (PPI) network construction were used to identify functional molecules related to IDD. PPI network unveiled that ESR1 was one of the most critical genes in IDD. Then, a key IDD-related circ_0040039-miR-874-3p-ESR1 interaction network was predicted and constructed. Circ_0040039 promoted miR-874-3p and repressed ESR1 expression, and miR-874-3p repressed ESR1 expression in NPCs, suggesting ESR1 might be a direct target of miR-874-3p. Functionally, circ_0040039 could enhance NPC apoptosis and inhibit NPC growth, revealing that circ_0040039 might aggravate IDD by stabilizing miR-874-3p and further upregulating the miR-874-3p-ESR1 pathway. This signaling pathway might provide a novel therapeutic strategy and targets for the diagnosis and therapy of IDD-related diseases.

Identification of Differentially Expressed circRNAs, miRNAs, and Genes in Patients Associated with Cartilaginous Endplate Degeneration.

BACKGROUND: Intervertebral disc degeneration (IDD) disease is a global challenge because of its predominant pathogenic factor in triggering low back pain, whereas cartilaginous endplate degeneration (CEPD) is the main cause of IDD. Accumulating evidence have indicated that the differentially expressed microRNAs (DEMs) and differentially expressed genes (DEGs) have been determined to be involved in multiple biological processes to mediate CEPD progression. However, the differentially expressed circular RNAs (DECs) and their potential biofunctions in CEPD have not been identified. METHODS: GSE153761 dataset was analyzed using R software to predict DECs, DEMs, and DEGs. Pathway enrichment analysis of DEGs and host genes of DECs and protein-protein interaction network of DEGs were conducted to explore their potential biofunctions. Furthermore, we explore the potential relationship between DEGs and DECs. RESULTS: There were 74 DECs, 17 DEMs, and 68 DEGs upregulated whereas 50 DECs, 16 DEMs, and 67 DEGs downregulated in CEPD group. Pathway analysis unveiled that these RNAs might regulate CEPD via mediating inflammatory response, ECM metabolism, chondrocytes apoptosis, and chondrocytes growth. A total of 17 overlapping genes were predicted between the host genes of DEGs and DECs, such as SDC1 and MAOA. Moreover, 6 upregulated DECs, of which hsa_circ_0052830 was the most upregulated circRNA in CEPD, were derived from the host genes SDC1, whereas 8 downregulated DECs were derived from the host genes MAOA. CONCLUSION: This will provide novel clues for future experimental studies to elucidate the pathomechanism of CEPD and therapeutic targets for CEPD-related diseases.

Emerging role of circular RNA in intervertebral disc degeneration: Knowns and unknowns (Review).

Lower back pain (LBP) is one of the predominant factors contributing to dyskinesia and remains a serious social and economic burden worldwide. Intervertebral disc degeneration (IDD) is the leading cause of LBP; the existing IDD treatments cannot completely prevent IDD. Circular RNAs (circRNAs) are non­coding RNAs resulting from back­splicing with unique structural characteristics and functions. Accumulating evidence suggests that circRNAs are involved in the pathological process of IDD and modulate a range of IDD­related genes or proteins. However, the underlying circRNA­mediated regulatory mechanisms remain poorly understood. The aim of the present review is to describe the current understanding of circRNA characteristics, classification, biogenesis and function in relation to its specific roles in IDD. Additionally, the limitations on the current knowledge in the field and the future direction of IDD­related research are also discussed.