Metformin prevents the onset and progression of intervertebral disc degeneration: New insights and potential mechanisms (Review).

Metformin has been the go­to medical treatment for addressing type 2 diabetes mellitus (T2DM) as a frontline oral antidiabetic. Obesity, cancer and bone deterioration are linked to T2DM, which is considered a metabolic illness. Numerous diseases associated with T2DM, such as tumours, cardiovascular disease and bone deterioration, may be treated with metformin. Intervertebral disc degeneration (IVDD) is distinguished by degeneration of the spinal disc, accompanied by the gradual depletion of proteoglycans and water in the nucleus pulposus (NP) of the IVD, resulting in lower back pain. The therapeutic effect of metformin on IVDD has also attracted much attention. By stimulating AMP­activated kinase, metformin could enhance autophagy and suppress cell senescence, apoptosis and inflammation, thus effectively delaying IVDD. The present review aimed to systematically explain the development of IVDD and mechanism of metformin in the treatment and prevention of IVDD to provide a reference for the clinical application of metformin as adjuvant therapy in the treatment of IVDD.

Automated detection, labelling and radiological grading of clinical spinal MRIs.

Spinal magnetic resonance (MR) scans are a vital tool for diagnosing the cause of back pain for many diseases and conditions. However, interpreting clinically useful information from these scans can be challenging, time-consuming and hard to reproduce across different radiologists. In this paper, we alleviate these problems by introducing a multi-stage automated pipeline for analysing spinal MR scans. This pipeline first detects and labels vertebral bodies across several commonly used sequences (e.g. T1w, T2w and STIR) and fields of view (e.g. lumbar, cervical, whole spine). Using these detections it then performs automated diagnosis for several spinal disorders, including intervertebral disc degenerative changes in T1w and T2w lumbar scans, and spinal metastases, cord compression and vertebral fractures. To achieve this, we propose a new method of vertebrae detection and labelling, using vector fields to group together detected vertebral landmarks and a language-modelling inspired beam search to determine the corresponding levels of the detections. We also employ a new transformer-based architecture to perform radiological grading which incorporates context from multiple vertebrae and sequences, as a real radiologist would. The performance of each stage of the pipeline is tested in isolation on several clinical datasets, each consisting of 66 to 421 scans. The outputs are compared to manual annotations of expert radiologists, demonstrating accurate vertebrae detection across a range of scan parameters. Similarly, the model's grading predictions for various types of disc degeneration and detection of spinal metastases closely match those of an expert radiologist. To aid future research, our code and trained models are made publicly available.

Correlation between degeneration of cervical intervertebral disc and degeneration of paravertebral muscle.

Objective: To investigate the relationship between degeneration of cervical intervertebral disc and degeneration of paravertebral muscles[multifidus (MF), cervical semispinalis (SCer), semispinalis capitis (SCap) and splenius capitis (SPL)]. Methods: 82 patients with chronic neck pain were randomly selected, including 43 males and 39 females, with 50.73 0.7.51 years old. All patients were scanned by 3.0T MRI Philips Ingenia performed conventional MRI sequence scanning and fat measurement sequence mDIXON-Quant scanning of cervical. Fat infiltration (FI) and cross-sectional area (CSA) of cervical paravertebral muscle (MF, SCer, SCap and SPL) at central level of C5-6 disc were measured by Philips 3.0T MRI image post-processing workstation. According to Pfirrmann grading system, there was no grade I in the included cases. The number of grade IIr IV cases were n=16, 40, 19 and 7 respectively. CSA and FI of cervical paravertebral muscles were compared with t test or one-way ANOVA, Spearman correlation analysis was used to evaluate the correlation between age, disc degeneration, and CSA, FI of cervical paravertebral muscles, and multiple linear regression analysis was used to analyze the independent influencing factors of CSA and FI. Results: CSA of cervical paravertebral muscles in male patients was significantly higher than that in female patients (all P<0.001), but there was no significant difference in FI (all P>0.05). Age was weakly correlated with CSA of MF+SCer, moderately correlated with CSA of SCap and SPL (r=-0.256, -0.355 and -0.361, P<0.05), weakly correlated with FI of SCap and SPL (r= 0.182 and 0.264, P<0.001), moderately correlated with FI of MF+SCer (r=0.408, P<0.001). There were significant differences in FI with disc degeneration (P<0.001, P=0.028 and P=0.005). Further correlation analysis showed that disc degeneration was strongly correlated with FI of MF+SCer (r=0.629, P<0.001), and moderately correlated with FI of SCap and SPL (r=0.363, P=0.001; r=0.345, P=0.002). Multiple linear regression analysis showed that sex and age were the influencing factors of CSA of SCap and SPL, sex was the independent influencing factor of CSA of MF+SCer, and disc degeneration was the independent influencing factor of FI. Conclusions: Age is negatively correlated with CSA and positively correlated with FI. Disc degeneration was correlated with FI of paravertebral muscles, especially with FI of MF and SCer. Sex and age were the influencing factors of CSA, while disc degeneration was the independent influencing factor of FI.

Surgical Treatment of Calcified Thoracic Herniated Disc Disease via the Transthoracic Approach with the Use of Intraoperative Computed Tomography (iCT) and Microscope-Based Augmented Reality (AR).

Background and Objectives: The aim of this study is to present our experience in the surgical treatment of calcified thoracic herniated disc disease via a transthoracic approach in the lateral position with the use of intraoperative computed tomography (iCT) and augmented reality (AR). Materials and Methods: All patients who underwent surgery for calcified thoracic herniated disc via a transthoracic transpleural approach at our Department using iCT and microscope-based AR were included in the study. Results: Six consecutive patients (five female, median age 53.2 ± 6.4 years) with calcified herniated thoracic discs (two patients Th 10-11 level, two patients Th 7-8, one patient Th 9-10, one patient Th 11-12) were included in this case series. Indication for surgery included evidence of a calcified thoracic disc on magnet resonance imaging (MRI) and CT with spinal canal stenosis of >50% of diameter, intractable pain, and neurological deficits, as well as MRI-signs of myelopathy. Five patients had paraparesis and ataxia, and one patient had no deficit. All surgeries were performed in the lateral position via a transthoracic transpleural approach (Five from left side). CT for automatic registration was performed following the placement of the reference array, with a high registration accuracy. Microscope-based AR was used, with segmented structures of interest such as vertebral bodies, disc space, herniated disc, and dural sac. Mean operative time was 277.5 ± 156 min. The use of AR improved orientation in the operative field for identification, and tailored the resection of the herniated disc and the identification of the course of dural sac. A control-iCT scan confirmed the complete resection in five patients and incomplete resection of the herniated disc in one patient. In one patient, complications occurred, such as postoperative hematoma, and wound healing deficit occurred. Mean follow-up was 22.9 ± 16.5 months. Five patients improved following surgery, and one patient who had no deficits remained unchanged. Conclusions: Optimal surgical therapy in patients with calcified thoracic disc disease with compression of dural sac and myelopathy was resectioned via a transthoracic transpleural approach. The use of iCT-based registration and microscope-based AR significantly improved orientation in the operative field and facilitated safe resection of these lesions.

S100A6 Regulates nucleus pulposus cell apoptosis via Wnt/ß-catenin signaling pathway: an in vitro and in vivo study.

BACKGROUND: Intervertebral disc degeneration (IDD) is a common musculoskeletal degenerative disease, which often leads to low back pain and even disability, resulting in loss of labor ability and decreased quality of life. Although many progresses have been made in the current research, the underlying mechanism of IDD remains unclear. The apoptosis of nucleus pulposus (NP) cells (NPCs) is an important pathological mechanism in intervertebral disc degeneration (IDD). This study evaluated the relationship between S100A6 and NPCs and its underlying mechanism. METHODS: Mass spectrometry, bioinformatics, and quantitative real-time polymerase chain reaction (qRT-PCR) analyses were used to screen and verify hub genes for IDD in human IVD specimens with different degeneration degrees. Western blotting, immunohistochemistry (IHC), and/or immunofluorescence (IF) were used to detect the expression level of S100A6 in human NP tissues and NPCs. The apoptotic phenotype of NPCs and Wnt/ß-catenin signaling pathway were evaluated using flow cytometry, western blotting, and IF. S100A6 was overexpressed or knocked down in NPCs to determine its impact on apoptosis and Wnt/ß-catenin signaling pathway activity. Moreover, we used the XAV-939 to inhibit and SKL2001 to activate the Wnt/ß-catenin signaling pathway. The therapeutic effect of S100A6 inhibition on IDD was also evaluated. RESULTS: S100A6 expression increased in IDD. In vitro, increased S100A6 expression promoted apoptosis in interleukin (IL)-1ß-induced NPCs. In contrast, the inhibition of S100A6 expression partially alleviated the progression of annulus fibrosus (AF) puncture-induced IDD in rats. Mechanistic studies revealed that S100A6 regulates NPC apoptosis via Wnt/ß-catenin signaling pathway. CONCLUSIONS: This study showed that S100A6 expression increased during IDD and promoted NPCs apoptosis by regulating the Wnt/ß-catenin signaling pathway, suggesting that S100A6 is a promising new therapeutic target for IDD.

The efficacy of 3D gait analysis to evaluate surgical (and rehabilitation) outcome after degenerative lumbar surgery.

BACKGROUND: Lumbar degenerative conditions are a major cause of back pain and disability in individuals aged 45 and above. Gait analysis utilizes sensor technology to collect movement data, aiding in the evaluation of various gait aspects like spatiotemporal parameters, joint angles, neuromuscular activity, and joint forces. It is widely used in conditions such as cerebral palsy and knee osteoarthritis. This research aims to assess the effectiveness of 3D gait analysis in evaluating surgical outcomes and postoperative rehabilitation for lumbar degenerative disorders. METHODS: A prospective self-controlled before-after study (n = 85) carried out at our Hospital (Sep 2018 - Dec 2021) utilized a 3D motion analysis system to analyze gait in patients with lumbar degenerative diseases. The study focused on the multifidus muscle, a crucial spinal muscle, during a minimally invasive lumbar interbody fusion surgery conducted by Shandong Weigao Pharmaceutical Co., Ltd. Pre- and postoperative assessments included time-distance parameters (gait speed, stride frequency, stride length, stance phase), hip flexion angle, and stride angle. Changes in 3D gait parameters post-surgery and during rehabilitation were examined. Pearson correlation coefficient was employed to assess relationships with the visual analog pain scale (VAS), Oswestry Disability Index (ODI), and Japanese Orthopedic Association (JOA) scores. Patient sagittal alignment was evaluated using "Surgimap" software from two types of lateral radiographs to obtain parameters like pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), lumbar lordosis (LL), intervertebral space height (DH), posterior height of the intervertebral space (PDH) at the operative segment, and anterior height of the intervertebral space (ADH). RESULTS: By the 6th week post-operation, significant improvements were observed in the VAS score, JOA score, and ODI score of the patients compared to preoperative values (P < 0.05), along with notable enhancements in 3D gait quantification parameters (P < 0.05). Pearson correlation analysis revealed a significant positive correlation between improvements in 3D gait quantification parameters and VAS score, JOA score, and ODI value (all P < 0.001). CONCLUSION: 3D gait analysis is a valuable tool for evaluating the efficacy of surgery and rehabilitation training in patients.

Comparative clinical efficacy of percutaneous coaxial large-channel endoscopic lumbar interbody fusion and transforaminal lumbar interbody fusion for degenerative lumbar spinal stenosis: a retrospective study.

This study aimed to evaluate the clinical efficacy of percutaneous coaxial large-channel endoscopic lumbar interbody fusion (PCLE-LIF) and transforaminal lumbar interbody fusion (TLIF) in the treatment of degenerative lumbar spinal stenosis. The clinical data of patients with degenerative lumbar spinal stenosis who underwent PCLE-LIF (experimental group) and TLIF (control group) surgery from September 2019 to September 2021 were retrospectively analyzed. We collected clinical data and compared the two groups in terms of perioperative parameters, treatment response rate, inflammatory response markers, postoperative complications, postoperative pain, and functional recovery. The results showed that the treatment outcomes in the experimental group were significantly better than those in the control group. Specifically, perioperative parameters and inflammatory response markers in the experimental group were significantly better than those in the control group, with statistically significant differences (P < 0.05). The overall treatment response rate in the experimental group was significantly higher than that in the control group (P < 0.05). Meanwhile, the incidence of postoperative complications in the experimental group was lower than that in the control group, postoperative VAS pain scores and ODI functional scores were lower, and postoperative JOA functional scores were higher than those in the control group, with statistically significant differences (P < 0.05). In conclusion, PCLE-LIF appears to be a promising technique with better clinical outcomes in the treatment of degenerative lumbar spinal stenosis.

Nuclear factor κB overactivation in the intervertebral disc leads to macrophage recruitment and severe disc degeneration.

Persistent inflammation has been associated with severe disc degeneration (DD). This study investigated the effect of prolonged nuclear factor κB (NF-κB) activation in DD. Using an inducible mouse model, we genetically targeted cells expressing aggrecan, a primary component of the disc extra cellular matrix, for activation of the canonical NF-κB pathway. Prolonged NF-κB activation led to severe structural degeneration accompanied by increases in gene expression of inflammatory molecules (Il1b, Cox2, Il6, and Nos2), chemokines (Mcp1 and Mif), and catabolic enzymes (Mmp3, Mmp9, and Adamts4). Increased recruitment of proinflammatory (F4/80+,CD38+) and inflammatory resolving (F4/80+,CD206+) macrophages was observed within caudal discs. We found that the secretome of inflamed caudal disc cells increased macrophage migration and inflammatory activation. Lumbar discs did not exhibit phenotypic changes, suggestive of regional spinal differences in response to inflammatory genetic overactivation. Results suggest prolonged NF-κB activation can induce severe DD through increases in inflammatory cytokines, chemotactic proteins, catabolic enzymes, and the recruitment and activation of macrophage cell populations.

Role of signaling pathways in age-related orthopedic diseases: focus on the fibroblast growth factor family.

Fibroblast growth factor (FGF) signaling encompasses a multitude of functions, including regulation of cell proliferation, differentiation, morphogenesis, and patterning. FGFs and their receptors (FGFR) are crucial for adult tissue repair processes. Aberrant FGF signal transduction is associated with various pathological conditions such as cartilage damage, bone loss, muscle reduction, and other core pathological changes observed in orthopedic degenerative diseases like osteoarthritis (OA), intervertebral disc degeneration (IVDD), osteoporosis (OP), and sarcopenia. In OA and IVDD pathologies specifically, FGF1, FGF2, FGF8, FGF9, FGF18, FGF21, and FGF23 regulate the synthesis, catabolism, and ossification of cartilage tissue. Additionally, the dysregulation of FGFR expression (FGFR1 and FGFR3) promotes the pathological process of cartilage degradation. In OP and sarcopenia, endocrine-derived FGFs (FGF19, FGF21, and FGF23) modulate bone mineral synthesis and decomposition as well as muscle tissues. FGF2 and other FGFs also exert regulatory roles. A growing body of research has focused on understanding the implications of FGF signaling in orthopedic degeneration. Moreover, an increasing number of potential targets within the FGF signaling have been identified, such as FGF9, FGF18, and FGF23. However, it should be noted that most of these discoveries are still in the experimental stage, and further studies are needed before clinical application can be considered. Presently, this review aims to document the association between the FGF signaling pathway and the development and progression of orthopedic diseases. Besides, current therapeutic strategies targeting the FGF signaling pathway to prevent and treat orthopedic degeneration will be evaluated.

Brain effect mechanism of lever positioning manipulation on LDH analgesia based on multimodal MRI: a study protocol.

INTRODUCTION: The clinical symptoms of Lumbar Disc Herniation (LDH) can be effectively ameliorated through Lever Positioning Manipulation (LPM), which is closely linked to the brain's pain-regulating mechanisms. Magnetic Resonance Imaging (MRI) offers an objective and visual means to study how the brain orchestrates the characteristics of analgesic effects. From the perspective of multimodal MRI, we applied functional MRI (fMRI) and Magnetic Resonance Spectrum (MRS) techniques to comprehensively evaluate the characteristics of the effects of LPM on the brain region of LDH from the aspects of brain structure, brain function and brain metabolism. This multimodal MRI technique provides a biological basis for the clinical application of LPM in LDH. METHODS AND ANALYSIS: A total of 60 LDH patients and 30 healthy controls, matched by gender, age, and years of education, will be enrolled in this study. The LDH patients will be divided into two groups (Group 1, n = 30; Group 2, n = 30) using a random number table method. Group 1 will receive LPM treatment once every two days, for a total of 12 times over 4 weeks. Group 2 will receive sham LPM treatment during the same period as Group 1. All 30 healthy controls will be divided into Group 3. Multimodal MRI will be performed on Group 1 and Group 2 at three time points (TPs): before LPM (TP1), after one LPM session (TP2), and after a full course of LPM treatment. The healthy controls (Group 3) will not undergo LPM and will be subject to only a single multimodal MRI scan. Participants in both Group 1 and Group 2 will be required to complete clinical questionnaires. These assessments will focus on pain intensity and functional disorders, using the Visual Analog Scale (VAS) and the Japanese Orthopaedic Association (JOA) scoring systems, respectively. DISCUSSION: The purpose of this study is to investigate the multimodal brain response characteristics of LDH patients after treatment with LPM, with the goal of providing a biological basis for clinical applications. TRIAL REGISTRATION NUMBER: https://clinicaltrials.gov/ct2/show/NCT05613179 , identifier: NCT05613179.

Bone Marrow Aspirate Concentrate Combined with Ultra-Purified Alginate Bioresorbable Gel Enhances Intervertebral Disc Repair in a Canine Model: A Preclinical Proof-of-Concept Study.

Although discectomy is commonly performed for lumbar intervertebral disc (IVD) herniation, the capacity for tissue repair after surgery is limited, resulting in residual lower back pain, recurrence of IVD herniation, and progression of IVD degeneration. Cell-based therapies, as one-step procedures, are desirable for enhancing IVD repair. This study aimed to investigate the therapeutic efficacy of a combination of newly developed ultra-purified alginate (UPAL) gel and bone marrow aspirate concentrate (BMAC) implantation for IVD repair after discectomy. Prior to an in vivo study, the cell concentration abilities of three commercially available preparation kits for creating the BMAC were compared by measuring the number of bone marrow mesenchymal stem cells harvested from the bone marrow of rabbits. Subsequently, canine-derived BMAC was tested in a canine model using a kit which had the highest concentration rate. At 24 weeks after implantation, we evaluated the changes in the magnetic resonance imaging (MRI) signals as well as histological degeneration grade and immunohistochemical analysis results for type II and type I collagen-positive cells in the treated IVDs. In all quantitative evaluations, such as MRI and histological and immunohistochemical analyses of IVD degeneration, BMAC-UPAL implantation significantly suppressed the progression of IVD degeneration compared to discectomy and UPAL alone. This preclinical proof-of-concept study demonstrated the potential efficacy of BMAC-UPAL gel as a therapeutic strategy for implementation after discectomy, which was superior to UPAL and discectomy alone in terms of tissue repair and regenerative potential.

The postoperative clinical effects of utilizing 3D printed (Ti6Al4V) interbody fusion cages in posterior lumbar fusion: A retrospective cohort study.

BACKGROUND: The research focused on the postoperative effect of using interbody fusion cage in lumbar posterior lamina decompression and interbody fusion with pedicle screw by comparing the postoperative effect of using 3D printing (Ti6Al4V) and PEEK material interbody fusion cage. METHODS: Ninety-one patients with lumbar degenerative diseases from the Department of Spine Surgery of Tianjin Hospital were included in the study cohort. They were divided into 3D group (n = 39) and PEEK group (n = 52) according to the use of interbody fusion cage. The imaging data of the patients were collected and the postoperative data of the 2 groups were compared to evaluate patients' health status and the recovery of lumbar structure and function after operation. RESULTS: Combined with the degree of fusion, the clinical effect of 3D printing titanium alloy interbody fusion cage was comprehensively judged. At the last follow-up, the JOA score, ODI index, VAS, prolo function score, and SF-36 scale of the 2 groups showed that the clinical symptoms were better than those before operation (P < .05). The height of intervertebral disc, the area of intervertebral foramen and the physiological curvature of lumbar vertebrae increased in varying degrees after operation (P < .05). At the last follow-up, the vertebral cage fusion rates were as high as 89.13% and 90.91% in the 3D and PEEK groups, with collapse rates of 6.5% and 4.5%, respectively. There were 10 cases of cage displacement in 3D group and 7 cases of cage displacement in PEEK group. There was no significant difference between the 2 groups (P > .05). CONCLUSIONS: In conclusion, 3D printed (Ti6Al4V) interbody fusion cage can obtain good clinical effect in the surgical treatment of lumbar degenerative diseases. Posterior lumbar lamina decompression, bilateral pedicle screw fixation combined with 3D printed cage interbody fusion is excellent in rebuilding the stability of lumbar vertebrae. 3D printed interbody fusion cage can be an ideal substitute material for intervertebral bone grafting. The stable fusion time of interbody fusion cage after lumbar fusion is mostly from 3 months to half a year after operation.

Comparative study of percutaneous endoscopic lumbar decompression and traditional revision surgery in the treatment of symptomatic adjacent segment degeneration.

OBJECTIVE: The objective of this study is to evaluate and compare the surgical outcomes and complications of Percutaneous Endoscopic Lumbar Decompression (PELD) and traditional revision surgery in treating symptomatic Adjacent Segment Degeneration (ASD). This comparison aims to delineate the advantages and disadvantages of these methods, assisting spine surgeons in making informed surgical decisions. METHODS: 66 patients with symptomatic ASD who failed conservative treatment for more than 1 month and received repeated lumbar surgery were retrospectively collected in the study from January 2015 to November 2018, with the average age of 65.86 ± 11.04 years old. According to the type of surgery they received, all the patients were divided in 2 groups, including 32 patients replaced the prior rod in Group A and 34 patients received PELD at the adjacent level in Group B. Patients were followed up routinely and received clinical and radiological evaluation at 3, 6, 12 months and yearly postoperatively. Complications and hospital costs were recorded through chart reviews. RESULTS: The majority of patients experienced positive surgical outcomes. However, three cases encountered complications. Notably, Group B patients demonstrated superior pain relief and improved postoperative functional scores throughout the follow-up period, alongside reduced hospital costs (P < 0.05). Additionally, significant reductions in average operative time, blood loss, and hospital stay were observed in Group B (P < 0.05). Notwithstanding these benefits, three patients in Group B experienced disc re-herniation and underwent subsequent revision surgeries. CONCLUSIONS: While PELD offers several advantages over traditional revision surgery, such as reduced operative time, blood loss, and hospital stay, it also presents a higher likelihood of requiring subsequent revision surgeries. Future studies involving a larger cohort and extended follow-up periods are essential to fully assess the relative benefits and drawbacks of these surgical approaches for ASD.

Enzymatic denaturation versus excessive fatigue loading degeneration: Effects on the time-dependent response of the intervertebral disc.

Degenerative disc disease (DDD), regardless of its phenotype and clinical grade, is widely associated with low back pain (LBP), which remains the single leading cause of disability worldwide. This work provides a quantitative methodology for comparatively investigating artificial IVD degeneration via two popular approaches: enzymatic denaturation and fatigue loading. An in-vitro animal study was used to study the time-dependent responses of forty fresh juvenile porcine thoracic IVDs in conjunction with inverse and forward finite element (FE) simulations. The IVDs were dissected from 6-month-old-juvenile pigs and equally assigned to 5 groups (intact, denatured, low-level, medium-level, high-level fatigue loading). Upon preloading, a sinusoid cyclic load (Peak-to-peak/0.1-to-0.8 MPa) was applied (0.01-10 Hz), and dynamic-mechanical-analyses (DMA) was performed. The DMA outcomes were integrated with a robust meta-model analysis to quantify the poroelastic IVD characteristics, while specimen-specific FE models were developed to study the detailed responses. The results demonstrated that enzymatic denaturation had a more significantly pronounced effect on the resistive strength and shock attenuation capabilities of the intervertebral discs. This can be attributed to the simultaneous disruption of the collagen fibers and water-proteoglycan bonds induced by trypsin digestion. Fatigue loading, on the other hand, primarily influenced the disc's resistance to deformation in a frequency-dependent pattern, where alterations were most noticeable at low loading frequencies. This study confirms the intricate interplay between the biochemical changes induced by enzymatic processes and the mechanical behavior stemming from fatigue loading, suggesting the need for a comprehensive approach to closely mimic the interrelated multifaceted processes of human disc degeneration.

Oxidative stress-induced EGR1 upregulation promotes NR4A3-mediated nucleus pulposus cells apoptosis in intervertebral disc degeneration.

This study aimed to reveal the specific role of early growth response protein 1 (EGR1) and nuclear receptor 4A3 (NR4A3) in nucleus pulposus cells (NPCs) and the related molecular mechanism and to identify a new strategy for treating intervertebral disc degeneration (IVDD). Bioinformatics analysis was used to explore and predict IVDD-related differentially expressed genes, and chromatin immunoprecipitation sequencing (ChIP-seq) revealed NR4A3 as the EGR1 target gene. An in vitro NPC model induced by tributyl hydrogen peroxide (TBHP) and a rat model induced by fibrous ring acupuncture were established. Western blotting, quantitative real-time polymerase chain reaction (qRT-PCR), immunohistochemical staining, immunofluorescence staining, and flow cytometry were used to detect the effects of EGR1 and NR4A3 knockdown and overexpression on NPC apoptosis and the expression of extracellular matrix (ECM) anabolism-related proteins. Interactions between EGR1 and NR4A3 were analyzed via ChIP-qPCR and dual luciferase assays. EGR1 and NR4A3 expression levels were significantly higher in severely degenerated discs (SDD) than in mildly degenerated discs (MDD), indicating that these genes are important risk factors in IVDD progression. ChIP-seq and RNA-seq revealed NR4A3 as a direct downstream target of EGR1, and this finding was verified by ChIP-qPCR and dual luciferase reporter experiments. Remarkably, the rescue experiments showed that EGR1 promotes TBHP-induced NPC apoptosis and impairs ECM anabolism, dependent on elevated NR4A3 expression. In summary, the EGR1-NR4A3 axis mediates the progression of NPC apoptosis and ECM impairment and is a potential therapeutic target in IVDD.

Progenitor-like cells contributing to cellular heterogeneity in the nucleus pulposus are lost in intervertebral disc degeneration.

The nucleus pulposus (NP) in the intervertebral disc (IVD) arises from embryonic notochord. Loss of notochordal-like cells in humans correlates with onset of IVD degeneration, suggesting that they are critical for healthy NP homeostasis and function. Comparative transcriptomic analyses identified expression of progenitor-associated genes (GREM1, KRT18, and TAGLN) in the young mouse and non-degenerated human NP, with TAGLN expression reducing with aging. Lineage tracing using Tagln-CreERt2 mice identified peripherally located proliferative NP (PeriNP) cells in developing and postnatal NP that provide a continuous supply of cells to the entire NP. PeriNP cells were diminished in aged mice and absent in puncture-induced degenerated discs. Single-cell transcriptomes of postnatal Tagln-CreERt2 IVD cells indicate enrichment for TGF-ß signaling in Tagln descendant NP sub-populations. Notochord-specific removal of TGF-ß/BMP mediator Smad4 results in loss of Tagln+ cells and abnormal NP morphologies. We propose Tagln+ PeriNP cells are potential progenitors crucial for NP homeostasis.

MGST1 May Regulate the Ferroptosis of the Annulus Fibrosus of Intervertebral Disc: Bioinformatic Integrated Analysis and Validation.

BACKGROUND: The objective of this research was to identify differentially expressed genes (DEGs) related to ferroptosis in the annulus fibrosus (AF) during intervertebral disc degeneration (IDD). METHODS: We analyzed gene data from degenerated and normal AF obtained from the GSE70362 and GSE147383 datasets. An analysis to determine the functional significance of the DEGs was conducted, followed by the creation of a network illustrating the interactions between proteins. We further analyzed the immune infiltration of the DEGs and determined the hub DEGs using LASSO regression analysis. Finally, we identified the hub ferroptosis-related DEGs (FRDEGs) and verified their expression levels using Real-time quantitative polymerase chain reaction (RT-qPCR), Western blot, Immunohistochemical Staining (IHC), and Immunofluorescence (IF). RESULTS: By analyzing the GSE70362 and GSE147383 datasets, we identified 118 DEGs. In degenerative AF groups, we observed a significant increase in immune infiltration of resting memory CD4+ T cells. LASSO regression analysis revealed 9 hub DEGs. The construction of a Receiver Operating Characteristic (ROC) curve yielded an Area Under the Curve (AUC) value of 0.762. Furthermore, we found that MGST1 is a hub gene related to ferroptosis. Our examination of immune infiltration indicated that MGST1 primarily influences macrophage M0 in different immune cell expression groups. Finally, our observations revealed a marked upregulation of MGST1 expression in the degenerated annulus fibrosus tissue. CONCLUSION: Our findings indicate an upsurge in MGST1 levels within degenerative AF, potentially playing a crucial role in the exacerbation of IDD. These findings provide a foundation for further exploration of the pathological mechanisms underlying IDD and offer potential drug targets for intervention.

Identifying the protective effects of miR-874-3p/ATF3 axis in intervertebral disc degeneration by single-cell RNA sequencing and validation.

Intervertebral disc degeneration (IVDD) severely affects the work and the quality of life of people. We previously demonstrated that silencing activation transcription factor 3 (ATF3) blocked the IVDD pathological process by regulating nucleus pulposus cell (NPC) ferroptosis, apoptosis, inflammation, and extracellular matrix (ECM) metabolism. Nevertheless, whether miR-874-3p mediated the IVDD pathological process by targeting ATF3 remains unclear. We performed single-cell RNA sequencing (scRNA-seq) and bioinformatics analysis to identify ATF3 as a key ferroptosis gene in IVDD. Then, Western blotting, flow cytometry, ELISA, and animal experiments were performed to validate the roles and regulatory mechanisms of miR-874-3p/ATF3 signalling axis in IVDD. ATF3 was highly expressed in IVDD patients and multiple cell types of IVDD rat, as revealed by scRNA-seq and bioinformatics analysis. GO analysis unveiled the involvement of ATF3 in regulating cell apoptosis and ECM metabolism. Furthermore, we verified that miR-874-3p might protect against IVDD by inhibiting NPC ferroptosis, apoptosis, ECM degradation, and inflammatory response by targeting ATF3. In vivo experiments displayed the protective effect of miR-874-3p/ATF3 axis on IVDD. These findings propose the potential of miR-874-3p and ATF3 as biomarkers of IVDD and suggest that targeting the miR-874-3p/ATF3 axis may be a therapeutic target for IVDD.

Can zoledronic acid reduce the risk of cage subsidence after oblique lumbar interbody fusion combined with bilateral pedicle screw fixation in the elderly population? A retrospective study.

BACKGROUND: The objective of this study was to evaluate the potential of zoledronic acid for reducing the incidence of cage subsidence and enhancing interbody fusion rates following oblique lumbar interbody fusion (OLIF) surgery, particularly as the first reported evidence of the role of zoledronic acid combined with OLIF. METHODS: A retrospective analysis was conducted on data from 108 elderly patients treated for degenerative lumbar diseases using OLIF combined with bilateral pedicle screw fixation from January 2018 to December 2021. Patients were divided into the zoledronic acid (ZOL) group (43 patients, 67 surgical segments) and the control group (65 patients, 86 surgical segments). A comparative analysis of the radiographic and clinical outcomes between the groups was performed, employing univariate and multivariate regression analyses to explore the relationships between cage subsidence and the independent variables. RESULTS: Radiographic outcomes, including anterior height, posterior height, disc height, coronal disc angle, foraminal height, and lumbar lordosis, were not significantly different between the two groups. Similarly, no statistically significant differences were noted in the back visual analog scale (VAS) scores and Oswestry Disability Index (ODI) scores between the groups. However, at the 1-year follow-up, the leg VAS score was lower in the ZOL group than in the control group (P = 0.028). The ZOL group demonstrated a notably lower cage subsidence rate (20.9%) than did the control group (43.0%) (P < 0.001). There was no significant difference in the interbody fusion rate between the ZOL group (93.0%) and the control group (90.8%). Non-use of zoledronic acid emerged as an independent risk factor for cage subsidence (OR = 6.047, P = 0.003), along with lower bone mineral density, lower postoperative anterior height, and concave endplate morphology. The model exhibited robust discriminative performance, with an area under the curve (AUC) of 0.872. CONCLUSION: The administration of zoledronic acid mitigates the risk of cage subsidence following OLIF combined with bilateral pedicle screw fixation in elderly patients; however, it does not improve the interbody fusion rate.

Unraveling the neuroimmune interface in chronic pain-the association between cytokines in the cerebrospinal fluid and pain in patients with lumbar disk herniation or degenerative disk disease.

ABSTRACT: Recent evidence highlights the importance of the neuroimmune interface, including periphery-to-central nervous system (CNS) neuroimmune crosstalk, in chronic pain. Although neuroinflammatory processes have been implicated in central sensitization for a long time, their potential neuroprotective and analgesic effects remain relatively elusive. We have explored the relationships between cytokine expression and symptom severity, and candidates for periphery-to-CNS crosstalk. Patients with degenerative disk disease (DDD) (nociceptive pain) or patients with lumbar disk herniation (LDH) with radiculopathy (predominantly neuropathic pain) completed questionnaires regarding pain and functional disability, underwent quantitative sensory testing, and provided blood and cerebrospinal fluid (CSF) samples. Proximity extension assay (PEA) was used to measure the levels of 92 inflammatory proteins in the CSF and serum from a total of 160 patients and controls, and CSF/serum albumin quotients was calculated for patients with DDD and patients with LDH. We found signs of neuroimmune activation, in the absence of systemic inflammation. Regarding periphery-to-CNS neuroimmune crosstalk, there were significant associations between several cytokines and albumin quotient, despite the latter being primarily at subclinical levels. The cytokines CCL11, CD5, IL8, and MMP-10 were elevated in the CSF, had positive correlations between CSF and serum levels, and associated in a nonlinear manner with back, but not leg, pain intensity in the LDH, but not the DDD, group. In conclusion, we found evidence for neuroimmune activation in the CNS of both patient groups in the absence of systemic inflammation and signs of a communication between CSF and serum. Complex and disease-specific associations were found between cytokines in CSF and back pain intensity.