Advances in bi-directional relationships for EZH2 and oxidative stress.

Over the past two decades, polycomb repressive complex 2(PRC2) has emerged as a vital repressive complex in overall cell fate determination. In mammals, enhancer of zeste homolog 2 (EHZ2), which is the core component of PRC2, has also been recognized as an important regulator of inflammatory, redox, tumorigenesis and damage repair signalling networks. To exert these effects, EZH2 must regulate target genes epigenetically or interact directly with other gene expression-regulating factors, such as LncRNAs and microRNAs. Our review provides a comprehensive summary of research advances, discoveries and trends regarding the regulatory mechanisms between EZH2 and reactive oxygen species (ROS). First, we outline novel findings about how EZH2 regulates the generation of ROS at the molecular level. Then, we summarize how oxidative stress controls EHZ2 alteration (upregulation, downregulation, or phosphorylation) via various molecules and signalling pathways. Finally, we address why EZH2 and oxidative stress have an undefined relationship and provide potential future research ideas.

Lactic acid promotes nucleus pulposus cell senescence and corresponding intervertebral disc degeneration via interacting with Akt.

The accumulation of metabolites in the intervertebral disc is considered an important cause of intervertebral disc degeneration (IVDD). Lactic acid, which is a metabolite that is produced by cellular anaerobic glycolysis, has been proven to be closely associated with IVDD. However, little is known about the role of lactic acid in nucleus pulposus cells (NPCs) senescence and oxidative stress. The aim of this study was to investigate the effect of lactic acid on NPCs senescence and oxidative stress as well as the underlying mechanism. A puncture-induced disc degeneration (PIDD) model was established in rats. Metabolomics analysis revealed that lactic acid levels were significantly increased in degenerated intervertebral discs. Elimination of excessive lactic acid using a lactate oxidase (LOx)-overexpressing lentivirus alleviated the progression of IVDD. In vitro experiments showed that high concentrations of lactic acid could induce senescence and oxidative stress in NPCs. High-throughput RNA sequencing results and bioinformatic analysis demonstrated that the induction of NPCs senescence and oxidative stress by lactic acid may be related to the PI3K/Akt signaling pathway. Further study verified that high concentrations of lactic acid could induce NPCs senescence and oxidative stress by interacting with Akt and regulating its downstream Akt/p21/p27/cyclin D1 and Akt/Nrf2/HO-1 pathways. Utilizing molecular docking, site-directed mutation and microscale thermophoresis assays, we found that lactic acid could regulate Akt kinase activity by binding to the Lys39 and Leu52 residues in the PH domain of Akt. These results highlight the involvement of lactic acid in NPCs senescence and oxidative stress, and lactic acid may become a novel potential therapeutic target for the treatment of IVDD.

Differential mRNA profiles reveal the potential roles of genes involved in lactate stimulation in mouse macrophages.

Lactate is a glycolysis end product, and its levels are markedly associated with disease severity, morbidity, and mortality in sepsis. It modulates key functions of immune cells, including macrophages. In this investigation, transcriptomic analysis was performed using lactic acid, sodium lactate, and hydrochloric acid-stimulated mouse bone marrow-derived macrophages (iBMDM), respectively, to identify lactate-associated signaling pathways. After 24 h of stimulation, 896 differentially expressed genes (DEG) indicated were up-regulation, whereas 792 were down-regulated in the lactic acid group, in the sodium lactate group, 128 DEG were up-regulated, and 41 were down-regulated, and in the hydrochloric acid group, 499 DEG were up-regulated, and 285 were down-regulated. Subsequently, clinical samples were used to further verify the eight genes with significant differences, among which Tssk6, Ypel4, Elovl3, Trp53inp1, and Cfp were differentially expressed in patients with high lactic acid, indicating their possible involvement in lactic acid-induced inflammation and various physiological diseases caused by sepsis. However, elongation of very long chain fatty acids protein 3 (Elovl3) was negatively correlated with lactic acid content in patients. The results of this study provide a necessary reference for better understanding the transcriptomic changes caused by lactic acid and explain the potential role of high lactic acid in the regulation of macrophages in sepsis.

A meta-analysis of the implementation of enhanced recovery after surgery pathways in anterior cervical spine surgery for degenerative cervical spine diseases.

OBJECTIVE: To systematically evaluate the perioperative effects of enhanced recovery after surgery (ERAS) protocol on anterior cervical spine surgery by means of meta-analysis. METHODS: According to the PRISMA guidelines, the article's search on the China National Knowledge Infrastructure (CNKI), Wanfang data resource system, VIP, PubMed database and Cochrane library was conducted to identify clinical studies investigating the effects of ERAS protocols on anterior cervical spine surgery. A quantitative meta-analysis was performed for the clinical outcomes extracted from the studies that met inclusion criteria. RESULTS: Of the 21 studies identified from the article search, 10 studies met inclusion criteria. The meta-analysis showed shorter length of stay (LOS) (MD = -2.16, 95% CI (-2.57, -1.75), P < 0.00001) and higher patient satisfaction for the ERAS protocols (OR = 3.13, 95% CI (1.97, 4.98), P < 0.00001). Furthermore, ERAS programs led to significant decreases in cost (MD = -0.81, 95% CI (-1.08, -0.53), P < 0.00001) and complication rates (OR = 0.15, 95% CI (0.08, 0.27), P < 0.00001), but no difference in 90-day readmission (OR = 0.63, 95% CI (0.30, 1.35), P = 0.24). CONCLUSIONS: The data of this study suggest that the implementation of ERAS protocol decreases LOS, cost and complications rates and improve satisfaction for the patients undergoing anterior cervical spine surgery. To support the practice use of ERAS in anterior cervical spine surgery further, controlled trials will be indispensable.

Development and validation of a nomogram to predict the risk of residual low back pain after tubular microdiskectomy of lumbar disk herniation.

OBJECTIVE: Tubular microdiskectomy (tMD) is one of the most commonly used for treating lumbar disk herniation. However, there still patients still complain of persistent postoperative residual low back pain (rLBP) postoperatively. This study attempts to develop a nomogram to predict the risk of rLBP after tMD. METHODS: The patients were divided into non-rLBP (LBP VAS score < 2) and rLBP (LBP VAS score ≥ 2) group. The correlation between rLBP and these factors were analyzed by multivariate logistic analysis. Then, a nomogram prediction model of rLBP was developed based on the risk factors screened by multivariate analysis. The samples in the model are randomly divided into training and validation sets in a 7:3 ratio. The Receiver operating characteristic (ROC) curve, calibration curve, and decision curve analysis (DCA) were used to evaluate the diskrimination, calibration and clinical value of the model, respectively. RESULTS: A total of 14.3% (47/329) of patients have persistent rLBP. The multivariate analysis suggests that higher preoperative LBP visual analog scale (VAS) score, lower facet orientation (FO), grade 2-3 facet joint degeneration (FJD) and moderate-severe multifidus fat atrophy (MFA) are risk factors for postoperative rLBP. In the training and validation sets, the ROC curves, calibration curves, and DCAs suggested the good diskrimination, predictive accuracy between the predicted probability and actual probability, and clinical value of the model, respectively. CONCLUSION: This nomogram including preoperative LBP VAS score, FO, FJD and MFA can serve a promising prediction model, which will provide a reference for clinicians to predict the rLBP after tMD.

A Biomimetic Peptide Functions as Specific Extracellular Matrix for Quiescence of Stem Cells against Intervertebral Disc Degeneration.

Maintaining quiescence of stem cells is a potential way to decrease cell nutrition demand for restoring the organization. Herein, a biomimetic peptide to maintain quiescence of stem cells through C-X-C motif chemokine ligand 8 (CXCL8)-C-X-C motif chemokine receptor 1 (CXCR1) pathway against intervertebral disc degeneration (IVDD) is developed. First, it is confirmed that quiescence can be induced via inhibiting phosphatidylinositol 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) pathway in nucleus pulposus stem cells (NPSCs). Meanwhile, it is well known that CXCR1, a chemokine receptor, can be targeted by CXCL8, resulting in cell proliferation via activating PI3K/Akt/mTOR pathway. Second, a biomimetic peptide (OAFF) that can bind to CXCR1 and form fibrous networks on NPSCs, mimicking extracellular matrix formation is developed. The multivalent effect and long-term binding to CXCR1 on NPSCs of OAFF fibers offer forcefully competitive inhibition with natural CXCL8, which induces NPSCs quiescence and ultimately overcomes obstacle in intradiscal injection therapy. In rat caudal disc puncture model, OAFF nanofibers still maintain at 5 weeks after operation and inhibit degeneration process of intervertebral disc in terms of histopathology and imageology. In situ fibrillogenesis of biomimetic peptide on NPSCs provides promising stem cells for intradiscal injection therapy against IVDD.

Enhanced recovery after microdiscectomy: reductions in opioid use, length of stay and cost.

BACKGROUND: Enhanced recovery after surgery (ERAS) protocols are widely used worldwide. Recently, studies of the ERAS program in spinal surgery subspecialties have been reported. The aim of this study was to evaluate the impacts of ERAS in minimally invasive microdiscectomy (MD) surgery. METHODS: This was a retrospective cohort study of patients undergoing MD at a single center. From March 2018 to March 2021, 286 patients were in the ERAS group. A total of 140 patients from March 2017 to February 2018 were in the conventional group. The outcomes included length of stay (LOS), the postoperative numeric rating scale (NRS), complications, 30-day readmission rate, 30-day reoperation rate and cost. Moreover, perioperative factors were also evaluated. RESULTS: Compared with the conventional group, the LOS and cost were reduced in the ERAS group. There were no significant differences in the NRS, complication rate, 30-day readmission or reoperation rates between the groups. Furthermore, postoperative drainage volume, and postoperative opioid use were lower in the ERAS group. CONCLUSIONS: The ERAS protocol for MD surgery reduces LOS, cost and opioid use and accelerates patient recovery.

A novel classification based on magnetic resonance imaging for individualized surgical strategies of lumbar disc herniation.

INTRODUCTION: Although the anatomy and pathology of lumbar disc herniation (LDH) have been clearly defined and classified in many studies, its imaging definition and classification still needs further clarification. This study intends to propose a novel classification and individualized surgical strategy for LDH based on preoperative magnetic resonance imaging (MRI). MATERIALS AND METHODS: According to MRI features, LDH types were identified, and the corresponding surgical strategies were formulated to accurately remove the herniated discs while minimizing the disturbance to the normal disc. We retrospectively analyzed prospectively collected data of LDH patients who underwent surgery guided by this classification system. RESULTS: This study included 357 patients with LDH who underwent tubular microdiscectomy. LDH was classified into four types based on MRI features. The inter- and intra-observer agreement using this classification was good. The follow-up results showed that surgery improved visual analog scale scores for low-back and leg pain and the Oswestry disability index in patients with different LDH types. The average recurrence rate at 1-5 years postoperatively was 5.62%. There was no significant difference in recurrence rates among the four LDH types (3.7-6.2%). MRI showed no significant differences in the Pfirrmann grade and disc height index of the operated segment between before surgery and 1-3 years after surgery. The operated segments did not show faster disc degeneration rates compared to adjacent proximal segments. CONCLUSIONS: We proposed a novel classification system and an individualized surgical strategy for LDH based on preoperative MRI. Further, the surgical suitable interventions guided by this system achieved good clinical outcomes and mild recurrence rates.

An enhanced recovery after surgery pathway: LOS reduction, rapid discharge and minimal complications after anterior cervical spine surgery.

BACKGROUND: Enhance recovery after surgery (ERAS) is a new and promising paradigm for spine surgery. The purpose of this study is to investigate the effectiveness and safety of a multimodal and evidence-based ERAS pathway to the patients undergoing anterior cervical discectomy and fusion (ACDF). METHODS: The patients treated with the ACDF-ERAS pathway were compared with a historical cohort of patients who underwent ACDF before ERAS pathway implementation. Primary outcome was length of stay (LOS). Secondary outcomes included cost, MacNab grading, complication rates and 90-day readmission and reoperation. And perioperative factors and postoperative complications were reviewed. RESULTS: The ERAS protocol was composed of 21 components. More patients undergoing multi-level surgery (n ≥ 3) were included in the ERAS group. The ERAS group showed a shorter LOS and a lower cost than the conventional group. The postoperative satisfaction of patients in ERAS group was better than that in conventional group. In addition, the rate of overall complications was significantly higher in the conventional group than that in the ERAS group. There were no significant differences in operative time, postoperative drainage, or 90-day readmission and reoperation. CONCLUSIONS: The ACDF-tailored ERAS pathway can reduce LOS, cost and postoperative complications, and improve patient satisfaction without increasing 90-day readmission and reoperation.

Roles of multimodal intra-operative neurophysiological monitoring (IONM) in percutaneous endoscopic transforaminal lumbar interbody fusion: a case series of 113 patients.

BACKGROUND: Despite the wide use of intraoperative neurophysiological monitoring (IONM) in spinal surgeries, the efficacy of IONM during percutaneous endoscopic transforaminal lumbar interbody fusion (PE-TLIF) surgery in detecting postoperative neurological deficits has not been well characterized. METHODS: MIONM data from 113 consecutive patients who underwent PE-TLIF surgeries between June 2018 and April 2020 were retrospectively reviewed. Postoperative neurological deficits were documented and analyzed, and the efficacy and specificity of various IONM techniques were compared. RESULTS: Of the 113 consecutive patients, 12 (10.6%) with IONM alerts were identified. The MIONM sensitivity and specificity were 100 and 96.2%, respectively. The frequency of neurological complications, including minor deficits, was 6.2% (n = 7); all of the neurological complications were temporary. The ability of single IONM modalities to detect neurological complications varied between 25.0 and 66.6%, whereas that of all modalities was 100%. CONCLUSIONS: MIONM is more effective and accurate than unimodal monitoring in assessing nerve root function during PE-TLIF surgeries, reducing both neurological complications and false-negative findings. We recommend MIONM in PE-TLIF surgeries.

Puerarin inhibits titanium particle-induced osteolysis and RANKL-induced osteoclastogenesis via suppression of the NF-κB signaling pathway.

Osteolysis around the prosthesis and subsequent aseptic loosening are the main causes of prosthesis failure. Inflammation due to wear particles and osteoclast activation are the key factors in osteolysis and are also potential targets for the treatment of osteolysis. However, it is not clear whether puerarin can inhibit chronic inflammation and alleviate osteolysis. In this study, we investigated the effect of puerarin on Ti particle-induced inflammatory osteolysis in vivo in rat femoral models and in vitro in receptor activator of nuclear factor kappa-B ligand (RANKL)-induced osteoclast activation models. Our in vivo results showed that puerarin significantly inhibited Ti particle-induced osteolysis and the expression of matrix metallopeptidase 9 (MMP-9), nuclear factor of activated T cells 1 (NFATc1), tumour necrosis factor (TNF)-α and interleukin (IL)-6. In vitro, puerarin prevented RANKL-induced osteoclast differentiation, bone resorption and F-actin ring formation in a concentration-dependent manner. Furthermore, puerarin decreased the phosphorylation of p65 and prevented p65 moving from the cytoplasm to the nucleus. Puerarin also reduced the expression of osteoclast-specific factors and inhibited the inflammatory response. In conclusion, our study proves that puerarin can block the NF-κB signalling pathway to inhibit osteoclast activation and inflammatory processes, which provides a new direction for the treatment of osteolysis-related diseases.

The matrikine N-acetylated proline-glycine-proline induces premature senescence of nucleus pulposus cells via CXCR1-dependent ROS accumulation and DNA damage and reinforces the destructive effect of these cells on homeostasis of intervertebral discs.

Intervertebral disc (IVD) cell senescence is a recognized mechanism of intervertebral disc degeneration (IDD). Elucidating the molecular mechanisms underlying disc cell senescence will contribute to understanding the pathogenesis of IDD. We previously reported that N-acetylated proline-glycine-proline (N-Ac-PGP), a matrikine, is involved in the process of IDD. However, its roles in IDD are not well understood. Here, using rat nucleus pulposus (NP) cells, we found that N-Ac-PGP induced premature senescence of NP cells by binding to CXCR1. N-Ac-PGP induced DNA damage and reactive oxygen species accumulation in NP cells, which resulted in activation of the p53-p21-Rb and p16-Rb pathways. Moreover, the RT2 profiler PCR array showed that N-Ac-PGP down-regulates the expression of antioxidant genes in NP cells, suggesting a decline in the antioxidants of NP cells. On the other hand, N-Ac-PGP up-regulated the expression of matrix catabolic genes and inflammatory genes in NP cells. Concomitantly, N-Ac-PGP reinforced the destructive effects of senescent NP cells on the homeostasis of the IVDs in vivo. Our study suggests that N-Ac-PGP plays critical roles in the pathogenesis of IDD through the induction of premature senescence of disc cells and via the activation of catabolic and inflammatory cascades in disc cells. N-Ac-PGP also deteriorates the redox environment of disc cells. Hence, N-Ac-PGP is a new potential therapeutic target for IDD.

Collagen-Derived N-Acetylated Proline-Glycine-Proline in Intervertebral Discs Modulates CXCR1/2 Expression and Activation in Cartilage Endplate Stem Cells to Induce Migration and Differentiation Toward a Pro-Inflammatory Phenotype.

The factors that regulate the migration and differentiation of cartilage endplate stem cells (CESCs) remain unknown. N-Acetylated proline-glycine-proline (N-Ac-PGP) is a chemokine that is involved in inflammatory diseases. The purpose of this study was to detect N-Ac-PGP in degenerative intervertebral discs (IVDs) and to determine its roles in the migration and differentiation of CESCs. Enzyme-linked immunosorbent assay (ELISA) and liquid chromatography-mass spectrometry results indicated that the levels of the proteases that generate N-Ac-PGP as well as N-Ac-PGP levels themselves increase with the progression of IVD degeneration. Immunohistochemistry and an N-Ac-PGP generation assay demonstrated that nucleus pulposus (NP) cells generate N-Ac-PGP from collagen. The effects of N-Ac-PGP on the migration and differentiation of CESCs were determined using migration assays, RT-PCR, immunoblot analysis, and ELISA. The results showed that the expression of N-Ac-PGP receptors (CXCR1 and CXCR2) in CESCs was upregulated by N-Ac-PGP. Additionally, N-Ac-PGP induced F-actin cytoskeletal rearrangement in CESCs and increased CESC chemotaxis. Furthermore, N-Ac-PGP recruited chondrocytes and spindle-shaped cells from the cartilage endplate (CEP) into the NP in vivo. These spindle-shaped cells expressed CD105 and Stro-1 (mesenchymal stem cell markers). N-Ac-PGP induced the differentiation of CESCs toward a pro-inflammatory phenotype with increased production of inflammatory cytokines rather than toward an NP-like phenotype. Our study indicated that, in the complex microenvironment of a degenerative disc, N-Ac-PGP is generated by NP cells and induces the migration of CESCs from the CEP into the NP. N-Ac-PGP induces a pro-inflammatory phenotype in CESCs, and these cells promote the inflammatory response in degenerative discs.

Growth and differentiation factor-5 contributes to the structural and functional maintenance of the intervertebral disc.

Intervertebral disc degeneration (IDD) is a widely recognized contributor to low back pain (LBP). The Prevention or reversal of IDD is a potential treatment for LBP. Unfortunately, current treatments for IDD are aimed at relieving symptoms rather than regenerating disc structure or function. Recently, the injection of growth factors and mesenchymal stem cell (MSC) transplantation have been shown to be promising biological therapies for IDD. Growth factors stimulate the proliferation of and matrix synthesis by intervertebral disc (IVD) cells, leading to the regeneration of degenerative discs. Growth factors, hypoxia and co-culture with nucleus pulposus (NP) cells induce MSCs to differentiate toward an NP-like phenotype, which can increase the number of functional cells in the IVD or enhance the function of endogenous disc cells to facilitate IVD regeneration. Therefore, the emerging roles of growth factors in IVD regeneration have piqued the interest of researchers. Growth factors including transforming growth factor-ß (TGF-ß), fibroblast growth factor (FGF), insulin-like growth factor-1 (IGF-1) and growth and differentiation factor-5 (GDF-5), among others, have been demonstrated to enhance anabolism in IVD cells and to induce NP-like differentiation of MSCs. However, the injection of TGF, IGF and FGF into human IVDs may induce unwanted blood vessel ingrowth, which accelerates the process of IDD, the injection of GDF-5 may not have the same effect. This finding suggests that GDF-5 is a preferable growth factor for use in IDD treatment compared with TGF, IGF and FGF. The GDF-5 gene is one of the few growth factor genes that have been found to be associated with IDD thus far; moreover, the GDF-5 gene defects lead to collagen and proteoglycan abnormalities in discs in mice, suggesting that GDF-5 contributes to the structural and functional maintenance of the IVD. This review is focused on the functions of GDF-5 in the IVD and on the association between GDF-5 and a genetic predisposition to IDD. The effects of GDF-5 on IVD regeneration and on MSC differentiation are also discussed. GDF-5 plays a crucial role in the pathogenesis of IDD and is a promising therapeutic agent for IDD. Additionally, stem cell transplantation has been shown to be a promising biological therapy for IDD.

Comparison of minimally invasive transforaminal lumbar interbody fusion (Mis-TLIF) with bilateral decompression via unilateral approach and open-TLIF with bilateral decompression for degenerative lumbar diseases: a retrospective cohort study.

OBJECTIVE: Presently, no study has compared the clinical outcomes of minimally invasive transforaminal lumbar interbody fusion (Mis-TLIF) with bilateral decompression via the unilateral approach (BDUA) and Open-TLIF with bilateral decompression for degenerative lumbar diseases (DLD). We aimed to compare the clinical outcomes of through Mis-TLIF combined with BDUA and Open-TLIF with bilateral decompression for the treatment of DLD, and reported the learning curve of the procedure of MIS-TLIF with BDUA. METHODS: We retrospectively analyzed the prospectively collected data of consecutive DLD patients in the two groups from January 2016 to January 2020. RESULTS: The operative time (OT) was significantly longer in the Mis-TLIF group (n = 113) than in the Open-TLIF group (n = 135). The postoperative drainage volume (PDV) and length of stay (LOS) were significantly higher in the Open-TLIF group than in the Mis-TLIF group. Additionally, the complication rate was significantly higher in the Open-TLIF group than in the Mis-TLIF group (14.8% vs. 6.2%, P = 0.030), while there was no significant difference in the reoperation and adjacent segment disease rates between the two groups. There were no significant differences in back pain and leg pain Numerical Rating Scale (NRS) scores and Oswestry Disability Index (ODI) between the two groups preoperatively, at discharge, and 2 years postoperatively. Patients in both groups showed significant improvements in NRS scores and ODI scores after surgery. OT was negatively correlated with the number of surgeries performed (P < 0.001, r = -0.43). The learning curve of Mis-TLIF with BDUA was steep, with OT tapered to steady state in 43 cases. CONCLUSION: Compared with Open-TLIF with bilateral decompression, Mis-TLIF with BDUA can achieve equivalent clinical outcomes, lower PDV and LOS, and lower complication rates. Although this procedure took longer, it could be a viable alternative for the treatment of DLD after a steep learning curve.

The sonic hedgehog pathway suppresses oxidative stress and senescence in nucleus pulposus cells to alleviate intervertebral disc degeneration via GPX4.

Disruption of intervertebral disc (IVD) homeostasis caused by oxidative stress and nucleus pulposus cell (NPC) senescence is a main cause of intervertebral disc degeneration (IDD). The sonic hedgehog (Shh) pathway plays an important role in IVD development, but its roles in IDD are unknown. This study aimed to investigate the effects of the Shh pathway on the alleviation of IDD and the related mechanisms. In vivo, the effect of the Shh pathway on IVD homeostasis was studied by intraperitoneal injection of recombinant Shh (rShh) and GANT61 based on puncture-induced IDD. GANT61, lentivirus-coated sh-Gli1 and rShh were used to investigate the role and mechanism of the Shh pathway in NPCs based on senescence induced by Braco19 and oxidative stress induced by TBHP. Shh pathway expression decreased, and senescence and oxidative stress increased with age. Intraperitoneal injection of rShh activated the Shh pathway to suppress oxidative stress and NPC senescence and consequently alleviated needle puncture-induced IDD. In vitro, the Shh pathway upregulated glutathione peroxidase 4 (GPX4) expression to suppress oxidative stress and senescence in NPCs. Moreover, GPX4 suppression in NPCs by si-GPX4 significantly reduced the protective effect of the Shh pathway on oxidative stress and senescence in NPCs. Our results demonstrate for the first time that the Shh pathway plays a key role in the alleviation of IDD by suppressing oxidative stress and cell senescence in NP tissues. This study provides a new potential target for the prevention and reversal of IDD.

Dynamics of N6-methyladenosine modification during aging and their potential roles in the degeneration of intervertebral disc.

Background: The N6-methyladenosine (m6A) dynamics in the progression of intervertebral disc (IVD) aging remain largely unknown. This study aimed to explore the distribution and pattern of m6A modification in nucleus pulpous (NP) tissues of rats at different ages. Methods: Histological staining and MRI were performed to evaluate the degeneration of IVD. The expression of m6A modifiers was analyzed using qRT-PCR and western blot. Subsequently, methylated RNA immunoprecipitation next generation sequencing and RNA-seq were conducted to identify differences in m6A methylome and transcriptome of NP tissues. Results: Compared to 2-month-old rats, we found significant changes in the global m6A level and the expression of Mettl3 and FTO in NP tissues from 20-month-old rats. During the progression of NP aging, there were 1126 persistently differentially m6A peaks within 931 genes, and 51 persistently differentially expressed genes. GO and KEGG analyses showed that these m6A peaks and m6A modified genes were mainly engaged in the biological processes and pathways of intervertebral disc degermation (IDD), such as extracellular matrix metabolism, angiogenesis, inflammatory response, mTOR and AMPK signaling pathways. Meanwhile, conjoint analyses and Venn diagram revealed a total of 405 aging related genes contained significant methylation and expression levels in 20-month-old rats in contrast to 2-month-old and 10-month-old rats. Moreover, it was found that four aging related genes with hypermethylated modification including BUB1, CA12, Adamts1, and Adamts4 depicted differentially expressed at protein level, of which BUB1 and CA12 were decreased, while Adamts1 and Adamts4 were increased during the progression of NP aging. Conclusion: Collectively, this study elucidated the distribution and pattern of m6A modification during the aging of IVD. Furthermore, the m6A modified genes were involved in the IDD related biological processes and pathways. These findings may provide novel insights into the mechanisms and therapies of IDD from the perspective of aging.

Predictive Factors for Dysphagia After Anterior Cervical Spine Surgery: A Prospective Multicenter Study.

OBJECTIVE: To identify the incidence and predictors of postoperative dysphagia in patients who undergo anterior cervical spine surgery (ACSS) by utilizing the Eating Assessment Tool (EAT-10). METHODS: A multicenter prospective study was undertaken at three hospitals to evaluate patients undergoing ACSS between January 2021 and January 2023. Included patients were aged 18-80 years and were undergoing primary or revision ACSS. Dysphagia was assessed using the validated EAT-10 questionnaire. Patients with dysphagia were included in the observation group, and those without dysphagia were included in the control group. RESULTS: Of the 343 patients enrolled, 50 patients (14.6%) had EAT-10 scores of 3 or more at the 6-month follow-up. In the univariate analysis, patients with dysphagia at 7 days had a longer operative time, were current smokers, had involvement of vertebral bodies at C4 and above, and underwent intraoperative neurophysiological monitoring. Patients with dysphagia at 6 months had involvement of vertebral bodies at C4 and above and underwent intraoperative neurophysiological monitoring. In the multivariate analysis to determine associations with prolonged dysphagia, only the involvement of vertebral bodies at C4 and above (odds ratio 3.883, 95% confidence interval 1.847-8.165, P = 0.001) and intraoperative neurophysiological monitoring (odds ratio 0.273, 95% confidence interval 0.080-0.931, P = 0.038) remained significant. CONCLUSIONS: Dysphagia is common after ACSS, affecting more than 67.5% of patients at 7 days postoperatively, but over time, the incidence of dysphagia gradually decreases. Involvement of the vertebral bodies at C4 and above is a risk factor for dysphagia after ACSS, and intraoperative neurophysiological monitoring is a protective factor.

Application of metagenomic next-generation sequencing in the detection of pathogens in spinal infections.

BACKGROUND CONTEXT: The precise diagnosis and treatment of spinal infections (SI) remains challenging for spine surgeons. Identifying the pathogens of SI through metagenomic next-generation sequencing (mNGS) may be a key approach to addressing this challenge. PURPOSE: To evaluate the accuracy and applicability of mNGS in determining the etiology of SI. STUDY DESIGN: Diagnostic test study. PATIENT SAMPLE: Twenty-five patients who had a clinical suspicion of SI and underwent mNGS testing. OUTCOME MEASURES: The specificity, sensitivity, and time cost of mNGS and bacterial culture were compared. Clinical outcomes were assessed using the numeric rating scale (NRS) score, Oswestry Disability Index (ODI), and the Japanese Orthopedic Association (JOA) score. Demographic data and laboratory results (blood cell count (WBC), erythrocyte sedimentation rate (ESR), neutrophil percentage (NEUT%), and C-reactive protein level (CRP) were also evaluated. METHODS: In this retrospective study, samples were obtained from 25 eligible patients via surgery or CT-guided puncture and subjected to histopathological examination, bacterial culture, and mNGS. The sensitivity and specificity of the bacterial cultures and mNGS were calculated with respect to the histopathological results as a reference. Postoperative antibiotics or antituberculosis drugs were administered on the basis of mNGS results, combined with clinical manifestations, imaging examination, and histopathology. The changes of clinical outcomes and laboratory results after treatment were observed. RESULTS: Of the 25 patients, 21 had a positive pathology, of which 10 showed a tuberculous pathology, and the remaining 11 showed a nontuberculous inflammatory pathology. The sensitivity of mNGS was higher than that of the bacterial culture. However, the difference in specificity between bacterial culture and mNGS was not significant. Moreover, the time needed to perform mNGS was significantly lower than that of bacterial culture and pathology. All patients were followed up for more than three months, and CRP and NEUT% significantly decreased by three months after treatment. There was no significant difference in WBC and ESR. The ODI, NRS and JOA scores were significantly improved after treatment. CONCLUSION: Metagenomic next-generation sequencing technology can play an important role in the detection of pathogens in SI and should be further investigated and applied in future studies.

Risk Factors of Low Back Pain Aggravation After Tubular Microdiscectomy of Lumbar Disc Herniation.

BACKGROUND: Although lumbar disc herniation (LDH) patients' sciatic symptoms such as leg pain can be improved by decompressive surgery, some patients report postoperative aggravated low back pain (LBP). However, the exact reason for this phenomenon remained unknown. METHODS: We retrospectively analyzed the prospectively collected LDH data of patients who underwent tubular microdiscectomy between December 2015 and December 2020. The patients were divided into aggravated and non-aggravated group according to whether the postoperative LBP visual analogue scale (VAS) score was higher than the preoperative score. We analyzed the relationship of the clinical and radiologic parameters with aggravated LBP. RESULTS: Postoperative aggravated LBP cases accounted for 14.1% (57 of 404) of this series. Of the 57 patients, 88% (50 of 57) had mild postoperative LBP aggravation (1-2), and 12% (7 of 57) had severe LBP aggravation (>2). The preoperative LBP VAS score of the aggravated group was significantly lower than that of the non-aggravated group (P < 0.001), while the LBP VAS score and Oswestry Disability Index at final follow-up was significantly higher in the aggravated group (P < 0.05). Additionally, the proportion of preoperative moderate-to-severe multifidus fatty atrophy (MFA) and lumbar facet joint degeneration (LFJD) was significantly higher in the aggravated group. A multiple stepwise logistic regression analysis indicated that the preoperative LBP VAS score (P < 0.001, odds ratio 0.266, 95% CI 0.161-0.439) and MFA (P < 0.001, odds ratio 4.491, 95% CI 2.092-9.640) were the risk factors for postoperative aggravated LBP. CONCLUSIONS: A preoperative lower LBP VAS score and moderate-to-severe MFA were associated with postoperative aggravated LBP. This will provide important guidance for patient's preoperative assessment and education.