Low back pain scores correlate with the cytokine mRNA level in lumbar disc biopsies: a study of inflammatory markers in patients undergoing lumbar spinal fusion

TIGAR attenuates intervertebral disc degeneration via autophagy-mediated Keap1 degradation and Nrf2 nuclear translocation to suppress nucleus pulposus pyroptosis

Pyroptosis plays a pivotal role in intervertebral disc degeneration (IVDD) driven by oxidative-inflammatory cascades, inducing nucleus pulposus (NP) cell lysis through gasdermin-mediated pore formation and subsequent release of proinflammatory cytokines, including IL-1β and IL-18. TP53-induced glycolysis and apoptosis regulator (TIGAR) alleviates oxidative stress by scavenging reactive oxygen species (ROS); however, its involvement in the autophagy-pyroptosis axis mediating IVDD remains unclear. In this study, we aimed to investigate how TIGAR delays IVDD progression via the autophagy-pyroptosis axis. First, we discovered from the NP tissues collected from patients undergoing lumbar spine surgeries and mice with needle puncture-induced models that the expression of TIGAR was reduced in severely degenerated tissues. In the IL-1β-induced human NP cell, TIGAR knockdown exacerbated the degradation of the extracellular matrix and pyroptosis, whereas TIGAR overexpression reversed this phenomenon. Ultrastructural analysis via transmission electron microscopy (TEM) and autophagic flux quantification revealed TIGAR-mediated autophagy in NP cells under inflammatory conditions. Co-immunoprecipitation assays validated the formation of a Keap1-p62-ubiquitin ternary complex, which directed Keap1 toward lysosome-dependent degradation and enhanced Nrf2 nuclear translocation. Therapeutic intradiscal delivery of AAV-TIGAR attenuated IVDD progression in mouse models, evidenced by preserved disc height index and reduced histopathological scores. Collectively, this work identified TIGAR as a redox-sensitive molecular switch that mitigated oxidative stress and inflammasome-driven pyroptosis through Keap1 autophagic clearance, offering a novel therapeutic paradigm for precision-targeted IVDD intervention.

Serum Interleukin-8 Levels and Their Association with Anxiety and Functional Disability in Military Personnel with Chronic Low Back Pain

Background/Objectives: Chronic low back pain (LBP) remains a leading cause of disability and healthcare utilization globally, with complex, multifactorial pathophysiology. Despite advances in imaging, diagnosis often remains challenging due to poor correlation between structural findings and clinical symptoms. Recent evidence suggests inflammatory mechanisms may underlie persistent pain. This study investigated whether systemic inflammatory cytokines are altered in military personnel with chronic LBP and examined their relationships with clinical manifestations, psychological factors, and radiological findings. Methods: In this cross-sectional study, we enrolled 50 patients with chronic non-specific LBP (duration ≥ 3 months) and 50 age-, sex-, and BMI-matched healthy controls. All patients underwent a comprehensive clinical assessment, which included evaluation of pain intensity (VAS), neuropathic pain screening (DN4), psychological assessment (HADS), fibromyalgia screening (FIRST), and assessment of functional disability (Oswestry Disability Index and Roland-Morris Disability Questionnaire, EIFEL). Serum levels of IL-6, IL-8, IL-1β, TNF-α, and IL-10 were measured using chemiluminescence and enzyme-linked immunosorbent assay (ELISA) techniques. Radiological findings were documented through MRI and CT imaging of the lumbar spine. Results: Serum IL-8 levels were significantly elevated in patients with chronic LBP compared to healthy controls (8.52 ± 6.7 vs. 4.8 ± 0.56 pg/mL, p < 0.001). Weak positive correlations were observed between IL-8 levels and anxiety scores (r = 0.3, p = 0.02) and functional disability, as measured by the EIFEL questionnaire (r = 0.3, p = 0.04); however, these associations did not remain significant after Bonferroni correction for multiple testing. Similarly, IL-6 showed a weak positive correlation with BMI (r = 0.21, p = 0.03) and a weak negative correlation with lumbar mobility, as assessed by Schober's test (r = -0.38, p = 0.03), which also did not survive correction for multiple comparisons. Conclusions: This study identified serum IL-8 as a potential biomarker for chronic LBP. While we observed associations between specific inflammatory markers and psychological distress and functional disability, these correlations were weak and did not remain significant after correction for multiple testing. These preliminary findings suggest possible connections between inflammation and the psychophysiological aspects of chronic LBP that warrant further investigation in larger cohorts.

Human molecular mechanisms of discogenic low back pain: A scoping review

The limited understanding of the mechanisms underlying human discogenic low back pain (DLBP) has hampered the development of effective treatments. While there is much research on disc degeneration, the association between degeneration and pain is weak. Therefore, there is an urgent need to identify pain-inducing molecular mechanism to facilitate the development of mechanism-specific therapeutics. This scoping review aims to determine the current knowledge of molecular mechanisms associated with human DLBP. A systematic search on CENTRAL, CINAHL, Citation searching, ClinicalTrials.gov, Embase, Google Scholar, MEDLINE, PsycINFO, PubMed, Scopus, Web of Science, and World Health Organization was performed. Studies with human DLBP as diagnosed by discography or imaging that analyzed human disc tissues and reported pain-related outcomes were included, and those on predominant radicular pain were excluded. The search returned 6012 studies. Most studies did not collect pain-related outcomes. Those that included pain assessment relied on self-report of pain intensity and disability. Six studies qualified for data extraction and synthesis. The main molecular mechanisms associated with DLBP were the expressions of nociceptive neuropeptides and cytokines, particularly TNF-αdue to its strong association with pain outcomes. Activation of NF-κB signaling pathway, alterations in adrenoceptor expressions, and increase in reactive oxygen species (ROS) were also associated with DLBP through regulation of pro-inflammatory factors and pain-related neuropeptides. Current evidence converges to TNF-α, NF-κB signaling, and ROS-induced pro-inflammation. Major weaknesses in the current literature are the focus on degeneration without pain phenotyping, and lack of association of molecular findings with pain outcomes. PERSPECTIVE: This scoping review identified TNF-α, NF-κB signaling, and ROS-induced pro-inflammation as relevant mechanisms of human discogenic low back pain. Major weaknesses in the current literature are the focus on degeneration without pain phenotyping, and lack of association of molecular findings with pain outcomes.

Role of macrophage in intervertebral disc degeneration

Intervertebral disc degeneration is a degenerative disease where inflammation and immune responses play significant roles. Macrophages, as key immune cells, critically regulate inflammation through polarization into different phenotypes. In recent years, the role of macrophages in inflammation-related degenerative diseases, such as intervertebral disc degeneration, has been increasingly recognized. Macrophages construct the inflammatory microenvironment of the intervertebral disc and are involved in regulating intervertebral disc cell activities, extracellular matrix metabolism, intervertebral disc vascularization, and innervation, profoundly influencing the progression of disc degeneration. To gain a deeper understanding of the inflammatory microenvironment of intervertebral disc degeneration, this review will summarize the role of macrophages in the pathological process of intervertebral disc degeneration, analyze the regulatory mechanisms involving macrophages, and review therapeutic strategies targeting macrophage modulation for the treatment of intervertebral disc degeneration. These insights will be valuable for the treatment and research directions of intervertebral disc degeneration.

Expression of cytokines at baseline correlate/predict in the disc the outcome of surgery after disc degeneration: A 12-month follow-up study

BACKGROUND

Low back pain (LBP) is a highly prevalent condition that comprise a large portion of outpatient practice, challenging the diagnosis and treatment. However, the diagnostic tools are limited to clinical history, physical examination and imaging. Degenerative disc disease (DDD) is a significant cause of LBP, and emerging literature confirms the elevated levels of biomarkers in the discs. These biomarkers may serve as a tool for diagnosis, but may also be useful in predicting the treatment outcome. Here, we examine the expression of various cytokines on 1-year recovery from patients with LBP.

METHODS

Patient-reported outcome (PRO) in terms of pain intensity (VAS), disability (ODI), and quality of life (Eq-5D) is collected from 44 patients at baseline and 12 months after surgery to study the influence of baseline TNF-α, IL-1β, and IL-6 mRNA expression in both annulus fibrosus (AF) and nucleus pulposus (NP).

RESULTS

Between baseline and follow-up, our cohort showed improvement in VAS back pain (p < 0.001), VAS leg pain (p < 0.001), ODI (p = 0.02), and Eq-5D (p = 0.01). Baseline levels of IL-1 β was positively correlated with VAS back pain scores in AF (p = 0.05) and NP (p = 0.01) at 1-year follow-up. TNF-α expression at baseline was also positively correlated to ODI scores (p = 0.01) at follow-up and inversely correlated to improvements in ODI score between baseline and follow-up, suggesting that high TNF-α expression at baseline is associated with poor outcomes from surgery.

CONCLUSION

The results from our study support that TNF-α expression at baseline can serve as a very important predictor of treatment response from lumbar fusion surgery.

Adipokines as potential pharmacological targets for immune inflammatory rheumatic diseases: Focus on rheumatoid arthritis, osteoarthritis, and intervertebral disc degeneration

Adipokines are a heterogeneous group of signalling molecules secreted prevalently by adipose tissue. Initially considered as regulators of energy metabolism and appetite, adipokines have been recognized for their substantial involvement in musculoskeletal disorders, including osteoarthritis, rheumatoid arthritis, and many others. Understanding the role of adipokines in rheumatic inflammatory and autoimmune diseases, as well as in other musculoskeletal diseases such as intervertebral disc degeneration, is crucial for the development of novel therapeutic strategies. Targeting adipokines, or their signalling pathways, may offer new opportunities for the treatment and management of these conditions. By modulating adipokines levels or activity, it may be possible to regulate inflammation, to maintain bone health, and preserve muscle mass, thereby improving the outcomes and quality of life for individuals affected by musculoskeletal diseases. The aim of this review article is to update the reader on the multifaceted role of adipokines in the main rheumatic diseases such as osteoarthritis and rheumatoid arthritis and to unravel the complex interplay among adipokines, cartilage metabolism, bone remodelling and muscles, which will pave the way for innovative therapeutic intervention in the future. For completeness, the role of adipokines in intervertebral disc degeneration will be also addressed.

Increased Expression of Inflammatory Cytokines and Discogenic Neck Pain

OBJECTIVE

Although neck pain has become a serious economic and social problem worldwide, the etiology remains poorly understood. The aim of current study is to explore the possible pathogenesis of discogenic neck pain by analyzing the relationship between inflammatory cytokines and discogenic neck pain and provide a valuable reference for the prevention and treatment of discogenic neck pain.

METHODS

A total of 111 cervical disc samples were collected between October 1, 2021, and October 1, 2022: 38 samples from the discogenic neck pain group, 41 samples from the symptomatic control group, and 32 samples from the normal control group. The concentration of nitric oxide (NO), interleukin (IL)-1, interleukin (IL)-6, and tumor necrosis factor alpha (TNF-α) was determined using the enzyme-linked immunosorbent assay in each sample, and the degeneration degree of the target discs were evaluated using T2-weighted sagittal magnetic resonance imaging (MRI) according to the Miyazaki disc degeneration grading system. Whether the differences among the three groups were statistically significant was tested using one-way analysis of variance and an unpaired t-test, respectively.

RESULTS

The differences of the baseline characteristics were not statistically significant between the discogenic neck pain group and the symptomatic control group (p > 0.05). The expression of inflammatory cytokines in disc samples from the discogenic neck pain group (NO: 9.89 ± 1.75, IL-1β: 10.74 ± 1.92, IL-6:31.65 ± 2.46, and TNF-α: 5.96 ± 1.91) was increased in comparison with the disc samples from both the symptomatic control group (NO: 7.15 ± 2.78, IL-1β: 8.03 ± 1.87, IL-6: 25.79 ± 2.12, and TNF-α: 4.18 ± 2.87) and the normal control group (NO: 6.11 ± 1.37, IL-1β: 5.84 ± 2.25, IL-6: 20.65 ± 1.26, and TNF-α: 2.05 ± 0.58). The differences were statistically significant (p < 0.001). Further, there were no statistical differences in the degree of degeneration between discogenic neck pain group and symptomatic control group.

CONCLUSIONS

The increased expression of inflammatory cytokines in diseased cervical intervertebral discs might play a key role in the pathogenesis of discogenic neck pain. Although inflammation is involved in intervertebral disc degeneration, there is no linear positive correlation between the concentration of inflammatory cytokines and the degree of disc degeneration.

Metalloproteases in Pain Generation and Persistence: A Possible Target?

Matrix metalloproteinases (MMPs) are a large family of zinc-dependent proteolytic enzymes associated with extracellular matrix protein turnover and tissue degradation. They participate to many different physiological reactions but are also hyperactivated in several diseases. Various literature studies have documented that MMPs play a role in the modulation of neuropathic and nociceptive pain. The heterogeneity of clinical and pre-clinical data is an important issue in this experimental context. Despite the presence of a good number of studies on MMP inhibitors, these drugs showed scarce efficacy and relevant side effects. In the present manuscript, we reviewed studies in the literature that define a possible role of MMPs in pain and the effects of their modulation.

Transient receptor potential (TRP) channels mRNA transcripts in the lumbar intervertebral discs: biomarkers for inflammation, pain, disability, and clinical outcome

Transient receptor potential (TRP) channels are widely expressed cation channels that play an essential role in mediating Ca2+ homeostasis and are considered potential regulators of inflammatory pain. This study investigates the expression of the TRP channel subtypes TRPV1, TRPV4, TRPC6, TRPM2, TRPM8 in lumbar intervertebral disc (IVD) biopsies from patients with chronic low back pain (LBP). We determined the expression of these TRP channel subtypes in the annulus fibrosus (AF) and the nucleus pulposus (NP) from 46 patients with LBP undergoing 1-2 level lumbar fusion surgery for degenerative disc disease. The mRNA transcripts were analyzed using quantitative real-time polymerase chain reaction (RT-qPCR), and the expression levels were compared against visual analog scale (VAS) and oswestry disability index (ODI) scores (0-100) for pain and disability. A significant positive correlation was demonstrated between VAS score and the mRNA expression of TRPV1, TRPC6, TRPM2, TRPM8 in the AF. We also found a significant positive correlation between ODI scores and expression of TRPV1 and TRPM8. Further, there is a significant positive correlation between TNF-α and TRPV1, TRPM2 and TRPM8 expression in the AF, and IL-6 to TRPV1 in the NP. Interestingly, when investigating treatment response via a 12-month postoperative follow-up ODI, we found a significant correlation between only TRPV1 expression at baseline and the follow-up ODI scores, which indicates this marker could predict the effectiveness of surgery. These results strongly suggest an association between pain, inflammatory mediators, and TRP channel expression in lumbar disc biopsies of patients with chronic LBP.

The expression of metalloproteinases in the lumbar disc correlates strongly with Pfirrmann MRI grades in lumbar spinal fusion patients

Introduction

Increased catabolism of the extracellular matrix is observed under degenerative disc disease (DDD). The cleavage of extracellular matrix proteins in the nucleus pulposus (NP) by either matrix metalloproteinases (MMPs) or a disintegrin and metalloproteinases with thrombospondin motifs (ADAMTSs) is believed to be involved in the degeneration, but the mechanisms are not known.

Research question

Here, we examine the correlation between expression of several MMPs and ADAMTSs subtypes in lumbar discs from 34 patients with low back pain (LBP) undergoing 1-2 level lumbar fusion surgery (L4/L5 and/or L5/S1) for DDD with or without spondylolisthesis.

Materials and Methods

The mRNA levels of MMPs (subtypes 1, 2, 3, 10, and 13) and ADAMTSs (subtypes 1, 4, and 5) were analyzed using quantitative real-time polymerase chain reaction (RT-qPCR) and correlated to the Pfirrmann magnetic resonance imaging classification system (grade I-V) of lumbar DDD.

Results

We find a highly significant positive correlation between Pfirrmann grades and the gene expression of MMP1 (r=0.67, p=0.0001), MMP3 (r=0.61, p=0.0002), MMP10 (r=0.6701, p=0.0001), MMP13 (r=0.48, p=0.004), ADAMTS1 (r=0.67, p=0.0001), and ADAMTS5 (r=0.53, p=0.0017). The similar regulation of these transcript suggests their involvement in disc degeneration. Interestingly, a post hoc analysis (uncorrected p-values) also demonstrated a positive correlation between expression of TNF-α, IL-6 and both ADAMTSs/MMPs and the Pfirrmann grades.

Discussion and Conclusion

These findings show that disc degradation in DDD is strongly associated with the expression of some metalloproteinases.

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An imbalance between catabolism and anabolism of IVD matrix components.

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MMPs and ADAMTSs are expressed in the NP, and their expression levels increase with degeneration grade.

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Our results suggest that inflammatory cytokines participate in the regulation of MMPs and ADAMTSs.