Patient-related risk factors and lifestyle factors for lumbar degenerative disc disease: a systematic review

In Vivo Measurements Reveal Increased Nucleus Pulposus Lactate and Oxygen Concentrations in a Goat Model of Intervertebral Disc Degeneration

Introduction

Intervertebral disc degeneration is strongly implicated as a cause of low back pain. Although the precise pathophysiological mechanisms remain elusive, perturbations in nutrition that adversely impact the cellular microenvironment of the central nucleus pulposus (NP) may be contributing factors. A comprehensive understanding of this microenvironment, including changes in nutrient availability as a function of degeneration, is critical for the development of effective cell-based treatments. The goal of this study was to adapt brain tissue oxygen probes and microdialysis catheters for in situ determination of relative NP oxygen, glucose, and lactate levels in a preclinical goat model of disc degeneration.

Methods

Following ex vivo technical refinement in bovine caudal discs, baseline metabolite measurements were performed in vivo in the lumbar discs of 3 large frame goats. Degeneration was then induced via injection of chondroitinase ABC (ChABC) into the NP, and measurements were repeated after 12 weeks. Degeneration severity was graded using magnetic resonance imaging (MRI) and histology, and vertebral endplate porosity was assessed using microcomputed tomography.

Results

Oxygen and lactate levels in goat NPs were significantly higher in degenerate compared to healthy discs, while glucose levels were not significantly different. ChABC-injected discs exhibited higher vertebral endplate porosity, worse histological and MRI grades, and a spectrum of cartilage endplate damage compared to healthy discs. There were significant positive correlations between MRI grade and both NP oxygen and lactate levels.

Discussion

We successfully adapted techniques including surgical placement, equilibration time, flow rate, and detection method for in situ measurement of oxygen, glucose, and lactate in a goat model of disc degeneration. Interestingly, while increased lactate with degeneration was expected, increased oxygen levels were unexpected. Our findings may, in part, be explained by associated alterations in disc and endplate structure, and motivate future studies to comprehensively establish the underlying mechanisms in this model.

Impact of obesity severity on postoperative outcomes and recovery progress in patients undergoing unilateral biportal endoscopy for degenerative lumbar disc herniation

Background

Obese patients undergoing Unilateral Biportal Endoscopy (UBE) surgery for degenerative lumbar disc herniation may experience postoperative recovery significantly influenced by the degree of obesity and related factors. This study aims to evaluate the impact of obesity severity on postoperative complications and recovery progress following UBE surgery and to identify key intervention points.

Methods

Preoperative baseline characteristics and postoperative follow-up data of patients with mild, moderate, and severe obesity were collected to analyze the incidence of complications, postoperative recovery trajectories, and key influencing factors. Multivariate logistic regression was conducted to examine factors affecting early mobilization (within 24 h), length of hospital stay, and anesthesia recovery time. Generalized linear mixed models (GLMM) were utilized to assess longitudinal changes in postoperative pain, functional disability, walking capacity, and muscle strength over time and their interactions with body mass index (BMI).

Results

Obesity severity was significantly associated with the incidence of postoperative complications. Multivariate logistic regression analysis identified BMI classification, disc calcification, lumbar spondylolisthesis, and inflammatory markers as independent predictors of functional recovery, hospital stay, and anesthesia recovery time. Obese patients showed delayed functional recovery at the 3-month follow-up. Greater obesity severity was associated with slower improvements in walking ability at 1 and 3 months postoperatively. Moreover, obesity severity demonstrated a significant negative correlation with electromyographic activity at 1 month postoperatively.

Conclusion

Obesity severity, inflammation, and anatomical factors are critical determinants of functional recovery in obese patients following UBE surgery. Patients with higher levels of obesity tend to have poorer mid- to long-term outcomes after UBE surgery. For such patients, enhanced postoperative mid- to long-term rehabilitation and physical function recovery are necessary to improve the prognosis of UBE.

Study on the safety and efficacy of Fu's subcutaneous needling for the treatment of lumbar disc herniation: a systematic review and meta analysis of randomized controlled trials

Purpose

Systematic evaluation of the effectiveness and safety of Fu's Subcutaneous Needling (FSN) in the treatment of Lumbar Disc Herniation.

Methods

A systematic search was conducted across four Chinese and four English databases, including China National Knowledge Infrastructure (CNKI), Wanfang, China Science and Technology Journal Database (VIP), China Biology Medicine (CBM), PubMed, Cochrane Library, Embase, and Web of Science, to collect randomized controlled trials (RCTs) on the use of Fu's subcutaneous needling for the treatment of lumbar disc herniation published before September 1, 2024. The search was conducted in both Chinese and English, with no restrictions on ethnicity. After rigorous screening of the literature, Meta-analysis was performed using Stata 18.0 and RevMan 5.2.1 software. This study protocol has been registered with the PROSPERO International Prospective Register of Systematic Reviews, with a registration number CRD42024595890.

Results

A total of 17 studies involving 1,467 patients were included. The Meta-analysis results indicated that Fu's subcutaneous needling for lumbar disc herniation was more effective than the control group, with a statistically significant difference. The overall effective rate was: OR = 2.77, 95% CI (1.90, 4.03), Z = 5.31, P < 0.00001. The VAS score was: MD = -1.12,95% CI (-1.35,-0.89),Z = 9.57,P < 0.00001. JOA scores was MD = 4.52, 95% CI (1.83, 7.2), Z = 3.29, P = 0.001.ODI scores with MD = -6.75, 95% CI (-8.42, -5.08), Z = 7.91, P < 0.00001. SF-36 with MD = 8.51, 95% CI (3.64, 13.38), Z = 3.42, P < 0.0006.

Conclusion

FSN has certain advantages and more safety in the treatment of LDH. However, due to the publication bias, the strength of the evidence is insufficient. High-quality, large-sample, multi-center randomized controlled trials are still needed for further research.

Systematic review registration

The protocol for this systematic review was registered on PROSPERO and is available in full on the website (https://www.crd.york.ac.uk/PROSPERO, CRD42024595890).

Lipid metabolic disorders and their impact on cartilage endplate and nucleus pulposus function in intervertebral disk degeneration

Lipid metabolism encompasses the processes of digestion, absorption, synthesis, and degradation of fats within biological systems, playing a crucial role in sustaining normal physiological functions. Disorders of lipid metabolism, characterized by abnormal blood lipid levels and dysregulated fatty acid metabolism, have emerged as significant contributors to intervertebral disk degeneration (IDD). The pathogenesis of IDD is multifaceted, encompassing genetic predispositions, nutritional and metabolic factors, mechanical stressors, trauma, and inflammatory responses, which collectively facilitate the progression of IDD. Although the precise mechanisms underlying IDD remain incompletely elucidated, there is substantial consensus regarding the close association between lipid metabolism disorders and its development. Intervertebral disks are essential for maintaining spinal alignment. Their primary functions encompass shock absorption, preservation of physiological curvature, facilitation of movement, and provision of stability. The elasticity and thickness of these disks effectively absorb daily impacts, safeguard the spine, uphold its natural curvature and flexibility, while also creating space for nerve roots to prevent compression and ensure normal transmission of nerve signals. Research indicates that such metabolic disturbances may compromise the functionality of cartilaginous endplates (CEP) and nucleus pulposus (NP), thereby facilitating IDD's onset and progression. The CEP is integral to internal material exchange and shock absorption while mitigating NP herniation under mechanical load conditions. As the central component of intervertebral disks, NP is essential for maintaining disk height and providing shock-absorbing capabilities; thus, damage to these critical structures accelerates IDD progression. Furthermore, lipid metabolism disorders contribute to IDD through mechanisms including activation of endoplasmic reticulum stress pathways, enhancement of oxidative stress levels, induction of cellular pyroptosis alongside inhibition of autophagy processes-coupled with the promotion of inflammation-induced fibrosis and fibroblast proliferation leading to calcification within intervertebral disks. This review delineates the intricate interplay between lipid metabolism disorders and IDD; it is anticipated that advancing our understanding of this pathogenesis will pave the way for more effective preventive measures and therapeutic strategies against IDD in future research.

Transcriptome Data Combined With Mendelian Randomization Analysis Identifies Key Genes Associated With Mitochondria and Programmed Cell Death in Intervertebral Disc Degeneration

Background

Intervertebral disc degeneration (IDD) is a major cause of cervical and lumbar diseases, significantly impacting patients' quality of life. Mitochondria and cell death have been implicated in IDD, but the key related genes remain unknown.

Methods

Differentially expressed genes (DEGs) between IDD and control samples were identified using GSE70362. Mitochondria-related genes (MRGs) and programmed cell death-related genes (PCDRGs) were intersected with DEGs to find DE-MRGs and DE-PCDRGs. Weighted gene co-expression network analysis (WGCNA) identified key module genes, and the overlap with DEGs revealed candidate genes. Mendelian randomization (MR) analysis was used to determine genes causally linked to IDD. Machine learning and expression validation further refined key genes, which were then used to build a nomogram to predict IDD risk. Additionally, gene set enrichment analysis (GSEA), immune infiltration, and single-cell analysis were performed.

Results

A total of 515 DEGs were intersected with 224 key module genes, yielding 31 candidate genes. Six genes-BCKDHB, BID, TNFAIP6, VRK1, CAB39L, and TMTC1-showed a causal relationship with IDD. BID, TNFAIP6, and TMTC1 were further identified as key genes through machine learning and validation. A nomogram was developed based on these genes. GSEA revealed BID and TMTC1 were enriched in N-glycan biosynthesis, TNFAIP6 and TMTC1 in aminoacyl tRNA biosynthesis, and BID and TMTC1 in ribosomal pathways. Activated dendritic cells, CD56dim natural killer cells, monocytes, and other immune cells were elevated in IDD, with TNFAIP6 strongly correlating with activated dendritic cells. Key genes were expressed at higher levels in degraded samples.

Conclusion

BID, TMTC1, and TNFAIP6 were identified as key genes linked to mitochondria and cell death in IDD, offering new insights for diagnosis and treatment.

Role of Platelet-Rich Plasma (PRP) in the Management of Stage III and IV Degenerative Disc Disease

Degenerative disc disease is a common disorder that can significantly impact patients' quality of life, leading to chronic pain and disability. Platelet-rich plasma (PRP) therapy is emerging as a potential treatment for degenerative disc disease. The purpose of this review is to summarize the role of PRP in the management of degenerative disc disease types III and IV. This is a scoping literature review. The online database PUBMED was used, and papers were searched using the keywords: ("PRP" OR "platelet-rich plasma") AND ("degenerative disk disease" OR "disk degeneration" OR "intradiscal injection" OR "discogenic pain" OR "intervertebral disc degeneration" OR "degenerative disk disease" OR "intervertebral disc disease"). Clinical studies evaluating the role of PRP in the management of stage III and IV degenerative disc disease were included in the study. Systematic reviews, animal studies, in vitro studies, case reports, study designs, case reports, and studies in languages other than English were excluded. The present study includes 14 studies. PRP has been found to promote tissue regeneration and modulate inflammatory response in degenerated discs. PRP can be administered mostly intradiscally but also epidurally. The benefits of PRP use include pain reduction, improvement of functionality, and low risk of adverse events. The effect of intradiscal PRP injections is similar to steroid injections. A higher concentration of platelets is associated with enhanced clinical outcomes. PRP therapy represents a promising avenue for tissue healing and regeneration across degenerative disc disease. While the evidence supporting its efficacy is encouraging, further research is needed to elucidate its mechanisms of action, optimize treatment protocols, and expand its clinical applications.

Combined single-cell RNA sequencing and mendelian randomization to identify biomarkers associated with necrotic apoptosis in intervertebral disc degeneration

BACKGROUND

Intervertebral disc degeneration (IDD) is associated with back pain; back pain is a world-wide contributor to poor quality of life, while necroptosis has the characteristics of necroptosis and apoptosis, however, its role in IDD is still unclear. Therefore, the aim of this study was to identify biomarkers associated with necroptosis in IDD.

PURPOSE

To explore biomarkers associated with necroptosis in IDD, reveal the pathogenesis of IDD, as well as provide new directions for the diagnosis and treatment of this disease.

STUDY DESIGN/SETTINGS

Retrospective cohort study. Our study employs scRNA-seq coupled with MR analysis to investigate the causal relationship between necroptosis and IDD, laying a foundational groundwork for unveiling the intricate pathogenic mechanisms of this condition.

METHODS

Data quality control and normalisation was executed in single-cell dataset, GSE205535. Then, different cell types were obtained by cell annotation through marker genes. Subsequently, chi-square test was employed to assess the distribution difference of different cell types between IDD and control to screen key cells. AUCell was applied to calculate necroptosis-related genes (NRGs) scores of all cell types, further key cells were divided into high and low NRGs groups according to the median AUC scores of different cell types. Afterwards, the differentially expressed genes (DEGs) within the 2 score groups were screened. Then, the genes that had causal relationship with IDD were selected as biomarkers by univariate and multivariate Mendelian randomization (MR) analysis. Finally, the expression of biomarkers in different cell types and pseudo-time analysis was analyzed separately.

RESULTS

In GSE205535, 16 different cell populations identified by UMAP cluster analysis were further annotated to 8 cell types using maker genes. Afterwards, 53 DEGs were screened between the high and low NRGs groups. In addition, 9 genes with causal relationship with IDD were obtained by univariate MR analysis, further multivariate MR analysis proved that NT5E and TMEM158 had a direct causal relationship with IDD, which were used as biomarkers in this study. This study not only found that the expression levels of NT5E and TMEM158 were higher in IDD group, but also found that fibrochondrocytes and inflammatory chondrocytes were the key cells of NT5E and TMEM158, respectively. In the end, the biomarkers had the same expression trend in the quasi-time series, and both of them from high to low and then increased.

CONCLUSIONS

NT5E and TMEM158, as biomarkers of necroptotic apoptotic IDD, were causally associated with IDD.

CLINICAL SIGNIFICANCE

The understanding of chondrocytes as key cells provides new perspectives for deeper elucidation of the pathogenesis of IDD, improved diagnostic methods, and the development of more effective treatments. These findings are expected to provide a more accurate and personalised approach to clinical diagnosis and treatment, thereby improving the prognosis and quality of life of patients with IDD.

Evidence from Mendelian randomization analysis combined with meta-analysis for the causal validation of the relationship between 91 inflammatory factors and lumbar disc herniation

Lumbar disc herniation (LDH) is a common spinal disease. In recent years, an increasing number of observational studies have reported the impact of inflammatory factors on LDH. By conducting Mendelian randomization (MR) analysis on 91 inflammatory factors, it is possible to reveal their causal relationship with LDH, providing new insights for prevention and treatment strategies. In this study, a two-sample MR analysis was performed, using 91 inflammatory factors as exposure data, and LDH data from 2 different sources as outcome data. Subsequently, the most significant results from the inverse-variance weighted analysis were subjected to meta-analysis, with multiple corrections applied to the thresholds to ensure result accuracy. Finally, reverse causality MR analysis was conducted to validate the causal relationship between the identified positive inflammatory factors and LDH. Ninety-one cytokines were analyzed in relation to LDH using MR with data from the Finngen and UK Biobank databases. The inverse-variance weighted results from both analyses were then meta-analyzed, and multiple corrections were applied to the significance threshold of the meta-analysis results. Ultimately, only 1 cytokine, tumor necrosis factor-beta levels (genome-wide association study ID: GCST90274840), showed a significant association after the combined MR analysis and multiple corrections, with an odds ratio of 1.073 (95% confidence interval: 1.034-1.113, P = .0154). Furthermore, this positive cytokine did not display any reverse causality with LDH from either data source. Tumor necrosis factor-beta levels are a risk factor for LDH, potentially increasing the risk of developing the condition and exacerbating its symptoms.

Association between lipid-lowering agents with intervertebral disc degeneration, sciatica and low back pain: a drug-targeted mendelian randomized study and cross-sectional observation

BACKGROUND

Abnormal lipid metabolism is linked to intervertebral disc degeneration (IVDD), sciatica, and low back pain (LBP), but it remains unclear whether targeted interventions can prevent these issues. This study investigated the causal effects of lipid-lowering drug use on IVDD, sciatica, and LBP development.

METHODS

Single-nucleotide polymorphisms (SNPs) linked to total cholesterol (TC), low-density-lipoprotein cholesterol (LDL-C), and non-high-density-lipoprotein cholesterol (non-HDL-C) were obtained from the Global Lipids Genetics Consortium's genome-wide association study (GWAS). Genes near HMGCR, PCSK9, and NPC1L1 were selected to represent therapeutic inhibition targets. Using Mendelian randomization (MR) focusing on these drug targets, we identified causal effects of PCSK9, HMGCR, and NPC1L1 on the risk of developing IVDD, sciatica, and LBP, with coronary heart disease risk serving as a positive control. Using summary data from Mendelian randomization (SMR) analysis, we evaluated potential therapeutic targets for IVDD, sciatica, and LBP through protein quantitative trait loci (pQTL). The genetic associations with IVDD, sciatica, LBP, and coronary heart disease were derived from FinnGen (discovery) and UK Biobank (replication). Additionally, a cross-sectional observational study was performed using data from the National Health and Nutrition Examination Survey (NHANES) to further investigate the connection between LBP and statin use, with a sample size of 4343 participants. Odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were calculated to assess the outcomes.

RESULTS

The NHANES-based cross-sectional study indicated that non-statin use was associated with an increased risk of developing LBP (OR = 1.29, 95% CI [1.04, 1.59], P = 0.019). Moreover, Inverse-variance weighting (IVW) analysis revealed that NPC1L1-mediated reductions in TC, LDL-C, and non-HDL-C concentrations were associated with a decreased risk of developing IVDD (P = 9.956E-03; P = 3.516E-02; P = 1.253E-04). Similarly, PCSK9-mediated reductions in LDL-C and TC concentrations were linked to a lower risk of developing sciatica (P = 3.825E-02; P = 2.709E-02). Sensitivity analysis confirmed the stability and reliability of the MR results. MST1 (macrophage stimulating 1) levels was inversely associated with IVDD, sciatica, and LBP risks.

CONCLUSION

The results of cross-sectional study suggested that non-use of statins was positively correlated with LBP. The results of Mendelian randomization study suggest that NPC1L1 could lower the risk of developing IVDD by reducing TC, LDL-C, and non-HDL-C levels. Additionally, PCSK9 may reduce the risk of developing sciatica by lowering LDL-C and TC levels. In contrast, HMGCR appears to have no significant effect on IVDD, sciatica, or LBP development. Nonetheless, further research is needed to verify these preliminary results. MST1 warrants further exploration as a potential therapeutic target. It is necessary to do further research to validate these findings.

Diabetes Mellitus and Intervertebral Disc Degeneration: A Meta-Analysis

BACKGROUND

Diabetes mellitus (DM) has been related to a higher risk of intervertebral disc degeneration (IVDD). However, the previous studies showed inconsistent results. We performed a systematic review and meta-analysis to comprehensively investigate the association between DM and IVDD in adult population.

METHODS

Observational studies relevant to the aim of the meta-analysis were retrieved by search of electronic databases including PubMed, Web of Science, and Embase. A random-effects model was used to combine the data by incorporating the influence of between-study heterogeneity.

RESULTS

Eleven observational studies involving 2,881,170 adults were included. Among them, 1,211,880 had DM. Compared to those with normoglycemia, patients with DM were associated with a higher odds ratio of IVDD (OR: 1.68, 95% confidence interval: 1.24 to 2.29, P<0.001; I2=98%). Further sensitivity analysis excluding database studies with IVDD diagnosed via International Classification of Diseases codes showed consistent results (odds ratio: 1.47, 95% confidence interval: 1.06 to 2.02, P=0.02) with no statistical heterogeneity (I2=0%). Subgroup analyses showed a stronger association between DM and IVDD in cohort studies than that in cross-sectional studies, in studies evaluating overall IVDD than that evaluating lumbar disc degeneration, and in studies that adjusted age and body mass index than that did not (P for subgroup differences all <0.05). Subgroup analyses according to study country and quality score did not significantly affect the association.

CONCLUSIONS

DM may be associated with IVDD in adult population, which seems to be independent of age and body mass index.

Causal relationship between basal metabolic rate and intervertebral disc degeneration: a Mendelian randomization study

BACKGROUND

The role of basal metabolic rate (BMR) in intervertebral disc degeneration (IVDD) is still uncertain. To address this gap, we conducted a Mendelian randomization (MR) study to comprehensively explore the causal relationship between BMR and IVDD.

METHODS

BMR data were obtained from a large genome-wide association study (GWAS) database, while IVDD data were derived from the FinnGen project. The causal relationship between IVDD and BMR was investigated using MR, with inverse-variance weighting (IVW) as the primary estimate. MR-Egger weighed median and weighed mode were employed for robustness. Sensitivity analyses, including the Cochran Q test, leave-one-out analysis, and MR-Egger intercept analysis, were conducted. Furthermore, the study also identified causal relationships between IVDD and factors associated with BMR (hyperthyroidism, type 2 diabetes, standing height, weight, and body mass index). Multivariable MR was applied to further assess the direct effect of BMR on IVDD.

RESULTS

Genetic predisposition to BMR (after removing outliers OR: 1.49; 95% CI: 1.37-1.63; P = 5.073e-21) were associated with an increased risk of IVDD. Additionally, IVDD risk increased with greater height, weight, and BMI. No causal relationship was observed between hy/thy and T2D and intervertebral disc degeneration (IVDD) (P > 0.05). In multivariable MR, a significant causal association between BMR and IVDD persisted, even after adjusting for BMI, height, and weight.

CONCLUSION

In this study, we successfully identified that a higher BMR is independently and causally linked to IVDD, indicating an increased risk of developing IVDD. These findings suggest that managing BMR could potentially mitigate the risk of IVDD.

Visualizing the bibliometrics of the inflammatory mechanisms in intervertebral disc degeneration

OBJECTIVE

Intervertebral disc degeneration (IVDD) constitutes a crucial pathological foundation for spinal degenerative diseases (SDD) and stands as a primary contributor to both low back pain (LBP) and disability. The progression of IVDD is linked to structural and functional alterations in tissues, where an imbalance in the inflammatory microenvironment can induce extracellular matrix (ECM) degradation, senescence, and apoptosis. This imbalance is a key pathomechanism in the disease's development, gaining considerable attention in recent years. This study aims to conduct a bibliometric analysis of publications pertaining to the inflammatory mechanisms of IVDD to quantitatively assess current research hotspots and directions.

METHODS

In this study, we queried the Web of Science Core Collection (WOSCC) database covering the period from January 1, 2001, to November 7, 2023. Content in this area was analyzed and visualized using software such as Citespace, Vosviewer, and the bibliometrix package.

RESULTS

Findings indicate a consistent annual increase in the number of publications, highlighting the widespread attention garnered by research on the inflammatory mechanisms of IVDD. In terms of journal research, Spine emerged with the highest number of publications, along with significantly elevated total citations and average citations compared to other journals. Regarding country analysis, China led in the number of publications, while the USA claimed the highest number of citations and total link strength. Institutional analysis revealed Sun Yat-sen University as having the highest number of publications and total link strength, with Thomas Jefferson University securing the highest total citations. Author analysis identified Ohtori, S. with the highest number of publications, Risbud, M.V. with the highest number of citations, and Inoue, G. with the highest total link strength, all of whom have made significant contributions to the field's development. Citation and co-citation analyses indicated that highly cited documents primarily focused on classical studies exploring inflammatory mechanisms in IVDD pathogenesis. Keyword analysis showcased the ongoing research hotspot as the further investigation of mechanisms and treatment studies. Recent years have seen a shift towards exploring pyroptosis, necrotic apoptosis, autophagy, ferroptosis, oxidative stress, and bacterial infection, among other mechanisms. In terms of treatment, alongside traditional monomer, drug, and compound therapies for IVDD, research is increasingly concentrating on stem cell therapy, exosomes, hydrogels, and scaffolds.

CONCLUSION

This bibliometric analysis of research on inflammatory mechanisms in IVDD provides insights into the current status, hotspots, and potential future trends. These findings can serve as a valuable reference and guide for researchers in the field.