Th17 lymphocyte levels are higher in patients with ruptured than non-ruptured lumbar discs, and are correlated with pain intensity

The association between inflammatory biomarkers and low back disorder: a systematic review and meta-analysis

INTRODUCTION

Low back disorder (LBD) is a major cause of disability worldwide. Inflammation results in proliferation of cytokines or consequent degradation products (collectively known as inflammatory biomarkers) that activate pain pathways which can result in non-specific LBD. This systematic review and meta-analysis aim to evaluate the relationship between inflammatory biomarkers and clinical outcomes in patients with LBD.

METHODS

The PRISMA guideline was followed for the systematic reivew. Three online databases were searched. Four RCTs and sixteen observational studies with 1142 LBD patients were analysed. The primary outcomes were back and leg pain scores, back-specific disability scores and expression of inflammatory biomarkers. Standardized mean difference (SMD) and their 95% confidence intervals (CI) were evaluated. The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach was used to summarize the strength of evidence.

RESULTS

Four RCTs and sixteen observational studies were included in the analysis of 1142 patients with LBD. There was a statistically significant reduction in back pain score and IL-1 beta and increase in the expression of CTX-1 and IL-10 levels post treatment. There was a significant relationship between increase in the expression of MCP- and reduction in the expression of hsCRP with increase in back pain. Significant relationship was also observed between increase in the expression of MCP-1 and reduction in the expression of IL-6 with increase in leg pain. Increase in the expression of IL-8 and reduction in the expression of hsCRP was also associated with increased disability score.

CONCLUSION

Inflammatory biomarkers play a significant role in the pathogenesis of LBD. CTX-1, IL-10 and IL-1 beta may be responsible for the decrease in back pain scores post treatment. There is a relationship between MCP-1, IL-6, IL-8 and hsCRP with clinical and functional assessments for LBD. Further studies will improve understanding of the pathogenesis of LBD and aid in targeted management strategies.

Research on the role and mechanism of IL-17 in intervertebral disc degeneration

Intervertebral disc degeneration (IDD) is one of the primary causes of low back pain (LBP), which seriously affects patients' quality of life. In recent years, interleukin (IL)-17 has been shown to be highly expressed in the intervertebral disc (IVD) tissues and serum of patients with IDD, and IL-17A has been shown to promote IDD through multiple pathways. We first searched databases such as PubMed, Cochrane, Embase, and Web of Science using the search terms "IL-17 or interleukin 17″ and "intervertebral discs". The search period ranged from the inception of the databases to December 2023. A total of 24 articles were selected after full-text screening. The main conclusion of the clinical studies was that IL-17A levels are significantly increased in the IVD tissues and serum of IDD patients. The results from the in vitro studies indicated that IL-17A can activate signaling pathways such as the NF-κB and MAPK pathways; promote inflammatory responses, extracellular matrix degradation, and angiogenesis; and inhibit autophagy in nucleus pulposus cells. The main finding of the in vivo experiments was that puncture of animal IVDs resulted in elevated levels of IL-17A within the IVD, thereby inducing IDD. Clinical studies, in vitro experiments, and in vivo experiments confirmed that IL-17A is closely related to IDD. Therefore, drugs that target IL-17A may be novel treatments for IDD, providing a new theoretical basis for IDD therapy.

Long-term changes of Th17 and regulatory T cells in peripheral blood of dogs with spinal cord injury after intervertebral disc herniation

BACKGROUND

Intervertebral disc herniation (IVDH) is one of the most common causes of spinal cord injury (SCI) in dogs. As a result of acute SCI, a complex inflammatory response occurs in the spinal cord. Th17 cells (Th17) produce pro-inflammatory cytokines, while regulatory T cells (Treg) have opposite effects producing anti-inflammatory cytokines. Therefore, the aim of this study was to determine whether Th17- and Treg cells are involved in the pathogenesis of SCI or whether cellular changes occur due to coexisting inflammatory diseases. We hypothesized that chronic alterations in the Th17/Treg ratio are associated with a worse outcome after SCI.

METHODS

Twenty-six paretic or plegic dogs with IVDH with and without coexisting inflammatory disease were investigated in the acute stage of the disease and after recovery of SCI. In addition, a healthy control group was included (n = 14). Quantification of Th17 and Treg cells, from peripheral blood samples, was performed by multicolor flow cytometry and IL17 was measured using an enzyme-linked immunosorbent assay (ELISA).

RESULTS

After recovery significantly higher levels of Th17 (p = 0.0265) and Treg cells (p = 0.00025) were detected compared to acute IVDH but Th17/Treg ratio did not differ significantly. Recovered dogs and the control group did not differ significantly from each other. No association between an imbalance in the ratio and neurologic severity or underlying inflammatory diseases was found.

CONCLUSION

This study demonstrated that altered Th17 and Treg levels in peripheral blood are altered in the acute stage of IVDH, preexisting inflammatory diseases seem not to influence these cell populations. Th17 and Treg cells could be considered when evaluating new treatment strategies for SCI.

Pro-inflammatory cytokines in patients with low back pain: A comparative study

INTRODUCTION AND OBJECTIVES

There are controversial results regarding the value of serum IL-8 and TNFα in patients with non-specific low back pain. This study aimed to compare pro-inflammatory cytokines between patients with non-specific back pain and pain-free controls.

MATERIALS AND METHODS

We conducted a case-control study including 106 participants: 46 patients with chronic non-specific low back pain (G1) and 60 pain-free controls (G0). The interleukin (IL-)6, IL-8, IL-17, IL-23, IL-22, and Tumor necrosis factor α (TNFα) were measured. We collected demographic and clinical data, including age, gender, low back pain duration and radicular pain. The pain degree was assessed using the Visual Analogic Scale.

RESULTS

The mean age was 43.17±8.7 years in G1. Radicular pain was found in 37 cases with a Visual Analogic Scale of 3.03±2.5mm. The magnetic resonance imaging was performed in (G1), showing disk herniation and degenerative disk disease in 54.3% (n=25) and 45.7% of cases (n=21), respectively. The IL-8 was higher in G1 (18.84±44.64 versus 4.34±1.23pg/mL, p:0.033). IL-8 levels correlated with TNFα (0.942, p<10-3), IL-6 (0.490, p=0.011) and Visual Analogic Scale_{Radicular-pain} (r:0.297, p:0.047). IL-17 was higher in patients with restricted lumbar spine mobility (9.64±20.77 versus 1.19±2.54pg/mL, p:0.014).

CONCLUSIONS

Our results provide evidence that IL-8 and TNFα play a role in low back pain and radicular pain due to disk degeneration or herniation. These findings could potentially be used by future studies to develop new non-specific low back pain therapeutic strategies.

Cytokine Imbalance as a Biomarker of Intervertebral Disk Degeneration

The intervertebral disk degeneration (IDD) and its associated conditions are an important problem in modern medicine. The onset of IDD may be in childhood and adolescence in patients with a genetic predisposition. IDD progresses with age, leading to spondylosis, spondylarthrosis, intervertebral disk herniation, and spinal stenosis. The purpose of this review is an attempt to summarize the data characterizing the patterns of production of pro-inflammatory and anti-inflammatory cytokines in IDD and to appreciate the prognostic value of cytokine imbalance as its biomarker. This narrative review demonstrates that the problem of evaluating the contribution of pro-inflammatory and anti-inflammatory cytokines to the maintenance or alteration of cytokine balance may be a new key to unlocking the mystery of IDD development and new therapeutic strategies for the treatment of IDD in the setting of acute and chronic inflammation. The presented data support the hypothesis that cytokine imbalance is one of the most important biomarkers of IDD.

Identifification and validation of ferroptosis signatures and immune infifiltration characteristics associated with intervertebral disc degeneration

Ferroptosis and immune infiltration play an important role in the pathogenesis of intervertebral disc degeneration (IDD). However, there is still a lack of comprehensive analysis on the interaction between ferroptosis-related genes (FRGs) and immune microenvironment in IDD patients. Therefore, this study aims to explore the correlation between FRGs characteristics and immune infiltration in the progression of IDD. The expression profiles (GSE56081 and GSE70362) and FRGs were downloaded from the comprehensive gene expression omnibus (GEO) and FerrDb database, respectively, and the differences were analyzed using R. The intersection of IDD related differential genes (DEGs) and FRGs was taken as differentially expressed FRGs (DE-FRGs) and GO and KEGG enrichment analysis was conducted. Then, we used least absolute shrinkage and selection operator (LASSO) regression algorithm and support vector machine (SVM) algorithm to screen feature genes and draw ROC curve judge the diagnostic value of key DE-FRGs. Then CIBERSORT algorithm is used to evaluate the infiltration of immune cells and analyze the correlation between key DE-FRGs and immune infiltration. Based on the analysis results, we conducted single gene GSEA analysis on key DE-FRGs. RT-PCR and immunohistochemistry further verified the clinical value of the results of biochemical analysis and screening. Seven key DE-FRGs were screened, including the upregulated genes NOX4 and PIR, and the downregulated genes TIMM9, ATF3, ENPP2, FADS2 and TFAP2A. Single gene GSEA analysis further elucidates the role of DE-FRGs in IDD associated with ferroptosis. Correlation analysis showed that seven key DE-FRGs were closely related to immune infiltration in the development of IDD. Finally, RT-PCR and immunohistochemical staining showed that NOX4, ENPP2, FADS2 and TFAP2A were statistically significant differences. In this study, we explored the connection between ferroptosis related characteristics and immune infiltration in IDD, and confirmed that NOX4, ENPP2, FADS2, and TFAP2A may become biomarkers and potential therapeutic targets for IDD.

Biomarkers in the Degenerative Human Intervertebral Disc Tissue and Blood

ABSTRACT

Patients with back pain comprise a large proportion of the outpatient practice among physiatrists. Diagnostic tools are limited to clinical history, physical examinations, and imaging. Nonsurgical treatments are largely empirical, encompassing medications, physical therapy, manual treatments, and interventional spinal procedures. A body of literature is emerging confirming elevated levels of biomarkers including inflammatory cytokines in patients with back pain and/or radiculopathy, largely because the protein assay sensitivity has increased. These biomarkers may serve as tools to assist diagnosis and assess outcomes.The presence of inflammatory mediators in the intervertebral disc tissues and blood helped to confirm the inflammatory underpinnings of back pain related to intervertebral disc degeneration. Literature reviewed here suggests that biomarkers could assist clinical diagnosis and monitor physiological outcomes during and after treatments for spine-related pain. Biomarkers must be measured in a large and diverse asymptomatic population, in the context of age and comorbidities to prevent false-positive tests. These levels can then be rationally compared with those in patients with back disorders including discogenic back pain, radiculopathy, and spinal stenosis. While studies reviewed here used "candidate marker" approaches, future nonbiased approaches in clearly defined patient populations could uncover novel biomarkers in clinical management of patients.

Interleukin-17 as a potential therapeutic target for chronic pain

Chronic pain remains to be a clinical challenge and is recognized as a major health problem with varying impacts on quality of life. Currently, the first-line therapy for chronic pain is opioids, which are often accompanied by unwanted psychoactive side effects. Thus, new and effective treatments for chronic pain are urgently needed and eagerly pursued. Inflammatory cytokines, especially interleukin-17 (IL-17), are reportedly potential therapeutic targets owing to their pivotal role in chronic pain from the neuroinflammation perspective. Recently, substantial evidence confirmed that IL-17 and IL-17 receptors (IL-17Rs) were increased in neuropathic, inflammatory, and cancer pain models. Notably, IL-17/IL-17R antibodies also reportedly relieve or cure inflammatory- and pain-related diseases. However, existing studies have reported controversial results regarding IL-17/IL-17Rs as potential therapeutic targets in diverse animal models of chronic pain. In this review, we present a summary of published studies and discuss the evidence, from basic to clinical to research, regarding the role and mechanism of action between IL-17 and diverse kinds of chronic pain in animal models and clinical patients. Furthermore, we evaluated IL-17-based therapy as a potential therapeutic strategy for inflammatory- and pain-related disease. Importantly, we also discussed clinical trials of IL-17/IL-17R targeting monoclonal antibodies. Overall, we found that IL-17 is a potential therapeutic target for chronic pain from the perspective of neuroinflammation.

Correlational analysis of chemokine and inflammatory cytokine expression in the intervertebral disc and blood in patients with lumbar disc disease

The involvement of intervertebral disc (IVD) tissues, whole blood (WB) cytokines, and chemokines in pain in patients with lumbar degenerative disc disease (LDD) is unknown. We investigated the relationships between inflammatory cytokines and chemokines in human IVD tissues and WB samples and their association with pain. Expression levels of chemokines and cytokine gene expression were measured in samples from 20 patients with LDD and compared between IVD tissues and WB samples. The associations between WB chemokine and cytokine gene expression levels and pain intensity (numeric rating scale) were also analyzed. The mRNA of C-C chemokine ligand 20 (CCL20), C-C chemokine receptor 6 (CCR6), interleukin-6 (IL-6), IL-1β, IL-17, and tumor necrosis factor-α (TNF-α) was expressed in degenerated IVD tissues. Pearson's product-moment correlation analysis produced positive correlations between CCR6 and IL-6 expression levels in IVD tissues (r = 0.845, p < 0.001) and WB samples (r = 0.963, p < 0.001). WB IL-6 and CCR6 mRNA expression levels correlated significantly with present pain, maximum pain, and average pain. By contrast, low back pain (LBP) did not correlate with serum chemokine/cytokine expression. This is the first study to report correlations between chemokine and inflammatory cytokine gene expression levels in IVD tissues and WB samples in patients with LDD in relation to pain intensity. WB CCR6 and IL-6 gene expression levels correlated significantly with present pain, maximum pain, and average pain, but not with LBP. These data provide a new understanding of the role of chemokines and inflammatory cytokines in patients with LDD and may lead to new treatment strategies for pain.

The Role of IL-17-Mediated Inflammatory Processes in the Pathogenesis of Intervertebral Disc Degeneration and Herniation: A Comprehensive Review

It has been reported that degenerated and herniated lumbar intervertebral discs show high expression of IL-17, suggesting that local immune reactions occur in patients with low back pain. While clinical sample analyses from different laboratories confirm this, it is not deeply not known on how IL-17 is induced in the pathology and their interactions with other inflammatory responses. This conscience review organizes current laboratory findings on this topic and present trajectory for full understanding on the role of IL-17 in pathology of intervertebral disc disease.

How Well Do Current Laboratory Biomarkers Inform Clinical Decision-Making in Chronic Pain Management?

OBJECTIVE

Decision-making in chronic pain patients involves a combination of subjective and objective criteria, including patient history, physical examination, imaging, and patient response to prior treatments, clinical experience, probabilities, and recognition of patterns. However, there is a distinct lack of objective laboratory biomarkers in use in routine clinical care. The objective was to review the literature to identify and describe specific biomarkers in chronic pain management.

METHODS

This is a narrative review of the literature regarding the use of laboratory biomarkers in chronic pain. A librarian-assisted literature search of the PubMed, Science Direct, and Google Scholar databases was performed and resulted in 304 possible manuscripts. We included manuscripts assessing laboratory collected biomarkers from urine, serum, cerebrospinal fluid, and saliva. After screening and review of the initial literature search results, a total of 75 manuscripts were included in the narrative review.

CONCLUSION

The studies reviewed suggested that specific biomarkers may help identify those patients at risk of disease development and function as a prognostic indicator for disease progression and treatment response. However, additional research is necessary before specific recommendations can be made, and current clinical decision-making is modified.

The role of T-lymphocytes in neuropathic pain initiation, development of chronicity and treatment

Ongoing research has strongly suggested the role the immune system plays in the pathogenesis of neuropathic pain. T cells appear to be one of the main regulators of the immune system with many mediators appearing to promote or suppress pain resolution. Limited effective therapies are available for treatment of neuropathic pain. Treatments available appear to modulate specific T cell with altered ratios present 3 months post treatment and parallels clinical improvement. This further supports the neuro-immune basis for neuropathic pain chronicity. Identification of novel immune mediators involved in pain development may suggest new target areas in treatment.

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Neuroimmunity plays a significant role in neuropathic pain pathogenesis neuropathic pain.

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Immune mediators contribute to promotion, suppression or resolution of neuropathic pain.

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Clinical studies in humans are lacking, most research available is pre-clinical or animal-based.

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Evidence-based therapies for treatment of neuropathic pain demonstrate alteration in T cell phenotype and behavior post therapy.

Evaluation of the involvement of Th17-cells in the pathogenesis of canine spinal cord injury

Intervertebral disc herniation (IVDH) is a frequently occurring neurological disease of dogs and the most common reason for spinal cord injury (SCI). Clinical signs are variable thus a reliable prognosis is crucial for further treatment decisions. Currently, the prognosis of IVDH primarily depends on presence or absence of deep pain perception. The purpose of this study was to investigate if Th17-cells could serve as a potential, prognostic biomarker for IVDH. We investigated a possible role of the adaptive immune system in the pathophysiology of IVDH in dogs. The investigation was performed by analyzing the influence of Th17-cells in blood and cerebrospinal fluid (CSF) of sixty-two dogs suffering from IVDH. In addition, we examined if Th17-cells might influence the course of this disease. As controls, paired blood and CSF samples of ten healthy clinic-owned dogs were examined and the values were compared to those of the IVDH group. Isolated lymphocytes were analyzed after stimulation by using multicolour flow cytometry to measure the number of Th17-cells. IL-17 levels were measured in paired serum and CSF samples by Enzyme‐linked Immunosorbent Assays (ELISA). Highly significant differences of stimulated Th17-cells in EDTA-blood samples could be determined between Th17-cell levels of dogs suffering from IVDH and the healthy control group and also between three sampling time points: preoperative, after clinical improvement and after six months. Preoperatively, Th17-cell levels were strongly decreased in contrast to the healthy controls. The decreased amount of Th17-cell levels recovered postoperatively so that Th17-cell levels of the last follow-up examinations were comparable to the control group after six months. At the same time IL-17 measured in serum preoperatively was significantly higher in dogs with IVDH than in healthy controls. However, there was no considerable difference of IL-17 measured in CSF between the groups. In conclusion, a high activity and consequent consumption of IL-17-producing Th17-cells is suspected in acute IVDH. These findings may indicate an involvement of Th17-cells in the pathogenesis of IVDH and emphasize that these cells might be involved in the interaction of pain, stress and immune reaction. However, based on the findings of this study the development of Th17-cells as a biomarker cannot be recommended, yet.

Lactobacillus paracasei S16 Alleviates Lumbar Disc Herniation by Modulating Inflammation Response and Gut Microbiota

Lumbar disc herniation (LDH) is a common cause for low back pain. In this study, we aimed to explore the effects of a specific Lactobacillus paracasei (L. paracasei), L. paracasei S16, on the symptoms of LDH using a mouse model of LDH. The results showed that L. paracasei S16 treatment improved the behavior, increased the cell proliferation, and decreased the apoptosis in LDH mice. Moreover, L. paracasei S16 treatment alleviated the aberrant inflammation response in the LDH mice, which is characterized by the decreased anti-inflammatory cytokines, increased pro-inflammatory cytokines, and decreased percentage of Th1 and Th2 cells and Th17/Treg ratio. 16S rRNA sequencing results showed that the LDH mice treated with L. paracasei S16 have higher relative abundance of Lachnospiraceae and Ruminococcaceae and lower abundance of Lactobacillaceae than mice in the LDH group. Additionally, the serum metabolites involved in the linoleic acid metabolism, alanine. aspartate, and glutamate, glycerophospholipid, and TCA cycle were significantly decreased and the metabolite involved in purine metabolism was significantly increased after the L. paracasei S16 treatment in the LDH mice. These results showed that administration of L. paracasei S16 can improve inflammation response, alter gut microbiota, and modulate serum metabolomics in a mouse model of LDH.

Inflammation in the intervertebral disc herniation

Up until fairly recently, it was thought that sciatic pain in the lumbar herniated disc was caused by compression on the nerve root. However, the lumbar herniated disc shows mixed pictures which are difficult to explain by simple mechanical compromise. In recent years various immunology, immunohistochemistry and molecular biology studies have shown that the herniated tissue is not an inert material, but rather it Is biologically very active with the capability of expressing a series of inflammatory mediators: cytokines such as interleukin-1, interleukin-6, interleuquin-8 and tumor necrosis factor being the ones which stand out. The inflammation is not only induced by the chemical irritation of the bioactive substances released by the nucleus pulposus but also by an autoimmune response against itself. Thus, in addition to the mechanical factor, the biomechanical mediation plays an important role in the pathophysiology of sciatic pain and of radiculopathy. Through a review of a wide range of literature, we researched the cellular molecular mediators involved in this inflammatory process around the lumbar herniated disc and its involvement in sciatic pain.

Can High-Sensitivity C-Reactive Protein Levels Predict Functional Outcome Following Epidural Steroid Injection in Patients with Lumbar Disc Disease?

Study Design

Prospective cohort study.

Purpose

Inflammatory cytokines produced at the site of disc herniation are considered as pain generators in patients with lumbar disc disease. Whether a high-sensitivity C-reactive protein (hs-CRP) assay can be used in order to predict the quantum of inflammation surrounding nerve roots is a matter of investigation. This study aimed to evaluate the association of hs-CRP level and functional outcomes measured by the Modified Oswestry Low Back Pain Disability Questionnaire (MODY) before and after epidural steroid injection (ESI) in patients with lumbar disc disease.

Overview of Literature

Although many studies examining the role of hs-CRP levels and lumbar pain have been published previously, the results are equivocal, and there is no clear consensus regarding which patients will benefit from an ESI.

Methods

This was a prospective study, with 77 patients in the study group and 23 participants in the control group. Baseline hs-CRP levels were obtained for both groups. Study group patients received a single ESI and were subjected to detailed pre- and post-procedure evaluation using MODY scores. For this group, hs-CRP levels were measured at 1 and 2 months after injection.

Results

Out of 77 patients, 52 had acute and 25 had chronic low back pain. Thirty-six patients with acute pain obtained significant improvement, while 16 had an insignificant response to the ESI. None of the chronic cases had a significant response. The mean baseline hs-CRP (mg/L) among the study group (29.83±10.43) was significantly higher than for the controls (10.26±2.783). The baseline hs-CRP among acute cases, where post ESI MODY score at 2 months had significant reduction, was 32.19±5.126, and those with insignificant reduction was 18.13±7.949 (p<0.001).

Conclusions

Baseline hs-CRP levels can be used to prognosticate the outcome following ESI in patients with acute lumbar disc disease, with radicular pain refractory to physiotherapy and analgesics.

Severity of intervertebral disc herniation regulates cytokine and chemokine levels in patients with chronic radicular back pain

OBJECTIVE

The contributions of intervertebral disc disease and subject-specific covariates to systemic inflammation in low back pain are unknown. We examined the effects of symptomatic disc herniation (DH) and MRI herniation severity on serum cytokine levels in clinical subjects.

DESIGN

Cytokine levels from lumbar DH subjects (N = 78) were compared to control subjects (N = 57) accounting for effects of DH, age, body mass index (BMI) and gender. Effect of DH severity on cytokine levels was analyzed on subsets of subjects with acute or chronic pain. Serum cytokines were also analyzed in a subset of patients between pre- and 3 months post-surgery.

RESULTS

Cytokine levels were elevated in the serum of patients with symptomatic DH, and the covariates age, BMI and gender significantly contributed to levels of some cytokines. Severity of herniation was a significant contributor to pain intensity (VAS), serum levels of HMGB1, PDGFbb, and IL-9. The relationship between DH severity and cytokine levels was confirmed in subjects with chronic, but not acute symptoms. Serum levels of macrophage migration inhibitory factor (MIF) decreased, whereas levels of CCL3, CCL11, CXCL1, and CXCL10 were significantly elevated post surgery.

CONCLUSIONS

This study is the first to show that DH severity is coordinately associated with changes in serum levels of inflammatory cytokines in chronic pain subjects. HMGB1, PDGFbb and IL-9 are novel mediators of increasing DH severity, indicative of cellular damage, neuro-inflammation and angiogenesis. Resolution of inflammation was observed with decrease in MIF post surgery. However, elevated chemokine levels indicate ongoing remodeling and wound healing at 3-month time point.

Apigenin Mitigates Intervertebral Disc Degeneration through the Amelioration of Tumor Necrosis Factor α (TNF-α) Signaling Pathway

Background

Intervertebral disc degeneration (IDD) is a common spinal disease affected by environmental and lifestyle factors that has a significant pathological cascade toward inflammation and partial disability. There is currently no therapy that can completely restore the cellular derangement in IDD. Hence, in this study, the therapeutic effects of apigenin on IDD were evaluated using a rat model.

Material/Methods

Animals were separated into 4 groups: Grp 1, sham-operated control; Grp 2, IDD-induced; Grp 3, IDD-induced+apigenin treatment; Grp 4, apigenin control. The animals were assessed for inflammatory cytokines, chemokines, and prostaglandin signaling.

Results

There were significant increases in the inflammatory cytokines IL-1β, IL-2, IL-6, IL-8 and IL-17 in the IDD-induced group compared to that of control. Moreover, with increased levels of MMP-3, MMP-9, ADAMTS-4, and syndecan-4, the levels of TNF-α, IFN-γ, prostaglandin E2, and cyclooxygenase 2 were directly increased in the IDD-induced group. In contrast, apigenin protectively restored levels of prostaglandin signaling and reduced cytokine levels. In addition, nucleus pulposus cells cultured separately with either TNF-α inhibitor or apigenin significantly attenuated the levels of extracellular matrix proteins.

Conclusions

The reduction of cytokine levels under apigenin treatment suggests it may be a promising target drug therapy for the treatment of deleterious IDD conditions.

Smoking Associated T-Cell Imbalance in Patients With Chronic Pain

INTRODUCTION

Smoking is associated with several diseases and affects the immune system. Recently, published data demonstrate an involvement of T helper 17 cells (Th17) and regulatory T cells (Tregs) in the pathogenesis of chronic pain and pain intensity. The role of these T-cell subsets in smoking patients with chronic pain is nebulous so far. We therefore analyzed Th17 cells and Tregs in smokers and nonsmokers with chronic pain.

METHODS

Analyses of T-cell subsets, mRNA expression and T-cell related cytokine profiles were done in 44 patients with chronic pain. Twenty-two of these patients were smokers. Numbers of T-cell subsets were quantified by flow cytometry. mRNA expression of the Th17- (RAR-related orphan receptor gamma) and Treg (forkhead box protein P3)-specific transcription factors was determined by quantitative real-time PCR, and levels of cytokines were measured by Human Cytokine Multiplex Immunoassay.

RESULTS

Compared to nonsmokers, smokers showed significantly enhanced pain levels. On cellular basis, the number of pro-inflammatory Th17 cells (smokers: 2.2 ± 2.5% vs. nonsmokers: 0.5 ± 0.4%; p = .04) was increased, whereas the number of anti-inflammatory Tregs (smokers: 2.5 ± 0.9% vs. nonsmokers: 3.1 ± 1.1%; p = .02) was significantly decreased, resulting in an altered Th17/Treg ratio (Th17/Treg ratio: 0.9 ± 1.0 in smokers vs. 0.2 ± 0.1 in nonsmokers; p < .01). These findings were confirmed by quantitative real-time PCR. Analyses of cytokines revealed only marginal changes.

CONCLUSIONS

In patients with chronic pain, smoking is associated with enhanced pain levels together with an imbalance of the Th17/Treg ratio. The shift of the Th17/Treg ratio toward inflammation may explain in part the increased pain intensity in these patients.

IMPLICATIONS

Smoking is associated with increased pain levels and a pro-inflammatory Th17/Treg shift. The altered Th17/Treg ratio in smoking patients with chronic pain may partly explain their increased pain intensity.

GERMAN CLINICAL TRIAL REGISTER (DRKS)

Registration Trial DRKS00005954.

Intervertebral Disc Diseases PART 2: A Review of the Current Diagnostic and Treatment Strategies for Intervertebral Disc Disease

With an aging population, there is a proportional increase in the prevalence of intervertebral disc diseases. Intervertebral disc diseases are the leading cause of lower back pain and disability. With a high prevalence of asymptomatic intervertebral disc diseases, there is a need for accurate diagnosis, which is key to management. A thorough understanding of the pathophysiology and clinical manifestation aids in understanding the natural history of these conditions. Recent developments in radiological and biomarker investigations have potential to provide noninvasive alternatives to the gold standard, invasive discogram. There is a large volume of literature on the management of intervertebral disc diseases, which we categorized into five headings: (a) Relief of pain by conservative management, (b) restorative treatment by molecular therapy, (c) reconstructive treatment by percutaneous intervertebral disc techniques, (d) relieving compression and replacement surgery, and (e) rigid fusion surgery. This review article aims to provide an overview on various current diagnostic and treatment options and discuss the interplay between each arms of these scientific and treatment advancements, hence providing an outlook of their potential future developments and collaborations in the management of intervertebral disc diseases.

MHCII-restricted T helper cells: an emerging trigger for chronic tactile allodynia after nerve injuries

Nerve injury-induced chronic pain has been an urgent problem for both public health and clinical practice. While transition to chronic pain is not an inevitable consequence of nerve injuries, the susceptibility/resilience factors and mechanisms for chronic neuropathic pain after nerve injuries still remain unknown. Current preclinical and clinical studies, with certain notable limitations, have shown that major histocompatibility complex class II–restricted T helper (Th) cells is an important trigger for nerve injury-induced chronic tactile allodynia, one of the most prevalent and intractable clinical symptoms of neuropathic pain. Moreover, the precise pathogenic neuroimmune interfaces for Th cells remain controversial, not to mention the detailed pathogenic mechanisms. In this review, depending on the biology of Th cells in a neuroimmunological perspective, we summarize what is currently known about Th cells as a trigger for chronic tactile allodynia after nerve injuries, with a focus on identifying what inconsistencies are evident. Then, we discuss how an interdisciplinary perspective would improve the understanding of Th cells as a trigger for chronic tactile allodynia after nerve injuries. Finally, we hope that the expected new findings in the near future would translate into new therapeutic strategies via targeting Th cells in the context of precision medicine to either prevent or reverse chronic neuropathic tactile allodynia.

Inflammatory biomarkers in patients with sciatica: a systematic review

BACKGROUND

This systematic review focusses on inflammation as an underlying pathogenic mechanism in sciatica. We addressed two questions in particular: (1) what inflammatory biomarkers have been identified in patients with sciatica in the literature so far? 2) is there an association between the level of inflammatory activity and clinical symptoms?

METHODS

The search was conducted up to December 19th 2018 in MEDLINE, EMBASE, CENTRAL and Web of Science. The study selection criteria: (1) observational cohort studies, cross-sectional studies and randomized clinical trials (RCT), (2) adult population (≥ 18 years) population with sciatica, (3) concentrations of inflammatory biomarkers measured in serum, cerebrospinal fluid (CSF) or biopsies, and (4) evaluation of clinically relevant outcome measures (pain or functional status). Three reviewers independently selected studies and extracted data regarding the study characteristics and the outcomes. Risk of Bias was evaluated using an adjusted version of the Quality in Prognosis Studies (QUIPS) tool.

RESULTS

In total 16 articles fulfilled the criteria for inclusion: 7 cross sectional observational studies and 9 prospective cohort studies that included a total of 1212 patients. With regard to question 1) the following markers were identified: interleukin (IL)-1β, IL-2, IL-4, IL-6, IL-8, IL-10, IL-17, IL-21, tumor necrosis factor-α (TNF-α), phospholipase A2, high sensitivity C-reactive protein (hsCRP), C-X-C motif chemokine 5 (CXCM5), CX3CL1, CCL2, epidermal growth factor (EGF), and monocyte chemotactic protein 4 (MCP-4). With regard to question 2) several positive correlations were found in longitudinal studies: a strong positive correlation between inflammatory mediators or byproducts and pain (measured by visual analogue scale, VAS) was found for IL-21 in two studies (r > 0,8), and moderate positive correlations for TNF-a in both serum (r = 0,629) and biopsy (r = 0.65); severe pain (VAS > 4) is associated with increased hsCRP levels among patients with sciatica (adjusted OR = 3.4 (95% CI, 1.1 to 10).

CONCLUSION

In this systematic review there was considerable heterogeneity in the type of biomarkers and in the clinical measurements in the included studies. Taking into account the overall risk of bias of the included studies there is insufficient evidence to draw firm conclusions regarding the relationship between inflammation and clinical symptoms in patients with sciatica.

Progranulin Is Positively Associated with Intervertebral Disc Degeneration by Interaction with IL-10 and IL-17 Through TNF Pathways

Progranulin (PGRN) is a widely expressed growth factor that effectively inhibits tumor necrosis factor α (TNFα)-mediated inflammatory response. TNFα is involved in intervertebral disc degeneration (IDD) and plays a key role. This study aims to determine the role of PGRN in the intervertebral disc degeneration process. We collected intervertebral discs (IVDs) from humans and mice with different genetic backgrounds. We examined the expression of PGRN in IVD tissues by immunohistochemistry staining and Western blotting assay. We examined the peripheral serum level of PGRN by ELISA assay. Murine IVD tissue samples were taken to undergo safranin O, HE, and immunohistochemistry staining. Primary human nucleus pulposus cells were used for ELISA and RT-PCR assays. PGRN as well as interlukin-10 (IL-10) and interlukin-17 (IL-17) expressions were elevated in degenerative discs and peripheral blood sera. Loss of PGRN led to accelerated disc degeneration in the animal model, along with decreased expression of IL-10 and increased expression of IL-17. Additionally, the PGRN level was positively related to levels of IL-10 and IL-17. In vitro study suggested that PGRN protected against disc degeneration by inducing IL-10 and reducing IL-17. PGRN is associated with intervertebral disc degeneration through interfering with IL-10 and IL-17; thus, PGRN could be an interesting biomarker for diagnosis and a potential treatment target.

Immunobiology of periprosthetic inflammation and pain following ultra-high-molecular-weight-polyethylene wear debris in the lumbar spine

INTRODUCTION

Wear debris-induced osteolysis is a common cause of arthroplasty failure in several joints including the knee, hip and intervertebral disc. Debris from the prosthesis can trigger an inflammatory response that leads to aseptic loosening and prosthesis failure. In the spine, periprosthetic pain also occurs following accumulation of wear debris through neovascularization of the disc. The role of the immune system in the pathobiology of periprosthetic osteolysis of joint replacements is debatable. Areas covered: We discussed the stimulation of pro-inflammatory and pro-protective and pro-regenerative pathways due to debris from the prosthetics. The balance between the two pathways may determine the outcome results. Also, the role of cytokines and immune cells in periprosthetic inflammation in the etiology of osteolysis is critically reviewed. Expert commentary: Therapies targeting the inflammatory process associated with ultra-high-molecular-weight polyethylene wear debris could reduce implant failure. Additionally, therapies targeting neovascularization of discs following arthroplasty could mitigate periprosthetic pain.

Inflammatory biomarkers of low back pain and disc degeneration: a review

Biomarkers are biological characteristics that can be used to indicate health or disease. This paper reviews studies on biomarkers of low back pain (LBP) in human subjects. LBP is the leading cause of disability, caused by various spine-related disorders, including intervertebral disc degeneration, disc herniation, spinal stenosis, and facet arthritis. The focus of these studies is inflammatory mediators, because inflammation contributes to the pathogenesis of disc degeneration and associated pain mechanisms. Increasingly, studies suggest that the presence of inflammatory mediators can be measured systemically in the blood. These biomarkers may serve as novel tools for directing patient care. Currently, patient response to treatment is unpredictable with a significant rate of recurrence, and, while surgical treatments may provide anatomical correction and pain relief, they are invasive and costly. The review covers studies performed on populations with specific diagnoses and undefined origins of LBP. Since the natural history of LBP is progressive, the temporal nature of studies is categorized by duration of symptomology/disease. Related studies on changes in biomarkers with treatment are also reviewed. Ultimately, diagnostic biomarkers of LBP and spinal degeneration have the potential to shepherd an era of individualized spine medicine for personalized therapeutics in the treatment of LBP.

Females with Unexplained Joint Pain Following Total Joint Arthroplasty Exhibit a Higher Rate and Severity of Hypersensitivity to Implant Metals Compared with Males: Implications of Sex-Based Bioreactivity Differences

BACKGROUND

Recent studies indicate that females demonstrate an increased risk of experiencing adverse local tissue reactions, aseptic loosening, and revision after primary metal-on-metal hip resurfacing arthroplasty compared with males; the underlying biological mechanisms responsible for sex discrepancies in implant failure remain unclear. In addition to anatomical and biomechanical sex differences, there may be inherent immunological disparities that predispose females to more aggressive adaptive immune reactivity to implant debris, i.e., metal sensitivity.

METHODS

In this retrospective study, we analyzed sex-associated rates and levels of metal sensitization in 1,038 male and 1,575 female subjects with idiopathic joint pain following total joint arthroplasty (TJA) who were referred for in vitro metal-sensitivity testing.

RESULTS

Females demonstrated a significantly higher rate and severity of metal sensitization compared with males. The median lymphocyte stimulation index (SI) among males was 2.8 (mean, 5.4; 95% confidence interval [CI], 4.9 to 6.0) compared with 3.5 (mean, 8.2; 95% CI, 7.4 to 9.0) among females (p < 0.05). Forty-nine percent of females had an SI of ≥4 (reactive) compared with 38% of males, and the implant-related level of pain was also significantly (p < 0.0001) higher among females (mean, 6.8; 95% CI, 6.6 to 6.9) compared with males (mean, 6.1; 95% CI, 6.0 to 6.3).

CONCLUSIONS

In a select group of patients who had joint pain following TJA and no evidence of infection and who were referred for metal-sensitivity testing, females exhibited a higher level of pain and demonstrated a higher rate and severity (as measured by lymphocyte SI) of metal sensitization compared with males.

LEVEL OF EVIDENCE

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Genes associated with persistent lumbar radicular pain; a systematic review

Background

The aim of the present study was to provide an overview of the literature addressing the role of genetic factors and biomarkers predicting pain recovery in newly diagnosed lumbar radicular pain (LRP) patients.

Methods

The search was performed in Medline OVID, Embase, PsycInfo and Web of Science (2004 to 2015). Only prospective studies of patients with LRP addressing the role of genetic factors (genetic susceptibility) and pain biomarkers (proteins in serum) were included. Two independent reviewers extracted the data and assessed methodological quality.

Results

The search identified 880 citations of which 15 fulfilled the inclusion criteria. Five genetic variants; i.e., OPRM1 rs1799971 G allele, COMT rs4680 G allele, MMP1 rs1799750 2G allele, IL1α rs1800587 T allele, IL1RN rs2234677 A allele, were associated with reduced recovery of LRP. Three biomarkers; i.e., TNFα, IL6 and IFNα, were associated with persistent LRP.

Conclusion

The present results indicate that several genetic factors and biomarkers may predict slow recovery in LRP. Still, there is a need for replication of the findings. A stricter use of nomenclature is also highly necessary.

Trial registration

The review is registered PROSPERO 20^th of November 2015. Registration number is CRD42015029125.

Evaluation of ceruloplasmin levels in patients with lumbar disc herniation

BACKGROUND

Chronic inflammation is believed to have a role in the development of lumbar disc herniation (LDH). Ceruloplasmin (CP), an acute phase protein, is known to limit inflammation.

OBJECTIVE

To evaluate CP levels in patients with LDH.

METHODS

Thirty-five patients with LDH and 35 healthy individuals were enrolled in the study. Participants were divided into two groups; group 1 (n = 35) consisted of patients with LDH, and group 2 (n = 35) consisted of healthy subjects. Surgery specimens were taken from all patients who underwent LDH-related surgery. CP levels were measured in both blood and tissue samples. Pain intensity was evaluated using a visual analog scale (VAS).

RESULTS

There were no significant differences in gender, age, or body mass index between the control and LDH patients (p > 0.05 for all). Compared with the control patients, LDH patients had significantly higher serum CP levels (p < 0.001). In LDH patients, tissue CP levels were significantly higher than serum levels (p < 0.001). According to bivariate analysis, the serum CP levels were significantly correlated with the VAS score in group 1 (r = 0.491, p = 0.003).

CONCLUSIONS

The present study showed that CP levels increased in both the serum and the tissues of patients with LDH compared to patients without LDH, possibly as a consequence of LDH-associated inflammation.

IL-17 mediates inflammatory reactions via p38/c-Fos and JNK/c-Jun activation in an AP-1-dependent manner in human nucleus pulposus cells

BACKGROUND

Low back pain and sciatica caused by intervertebral disc (IVD) disease are associated with inflammatory responses. The cytokine interleukin 17 (IL-17) is elevated in herniated and degenerated IVD tissues and acts as a regulator of disc inflammation. The objective of this study was to investigate the involvement of IL-17A in IVD inflammatory response and to explore the mechanisms underlying this response.

METHODS

Cells were isolated from nucleus pulposus (NP) tissues collected from patients undergoing surgeries for IVD degeneration. The concentrations of COX2 and PGE2, as well as of select proteins involved in the mitogen-activated protein kinase (MAPK)/activating protein-1 (AP-1) pathway, were quantified in NP cells after exposure to IL-17 with or without pretreatment with MAPK or AP-1 inhibitors.

RESULTS

Our results showed that IL-17A increased COX2 expression and PGE2 production via the activation of MAPKs, including p38 kinase and Jun N-terminal kinase (JNK). Moreover, IL-17A-induced COX2 and PGE2 production was shown to rely on p38/c-Fos and JNK/c-Jun activation in an AP-1-dependent manner.

CONCLUSION

In summary, our results indicate that IL-17A enhances COX2 expression and PGE2 production via the p38/c-Fos and JNK/c-Jun signalling pathways in NP cells to mediate IVD inflammation.

Interleukin-23 may contribute to the pathogenesis of lumbar disc herniation through the IL-23/IL-17 pathway

BACKGROUND

Studies have indicated that interleukin 23 (IL-23) plays an important role in many inflammatory- and autoimmune-related diseases. However, there is little knowledge about IL-23 in lumbar disc herniation (LDH). Thus, in this study, we aimed to find out whether IL-23 is expressed in intervertebral discs (IVDs) and what roles it may play.

METHODS

Human IVD tissues were collected from 29 LDH patients and 8 vertebral fracture patients (normal control, NC group). According to the integrity of annulus fibrosus, LDH patients were divided into two groups: R group (ruptured group, n = 16) and NR group (non-ruptured group, n = 13). Morphological changes of IVDs were assessed by hematoxylin and eosin (HE staining), and expression of IL-23 in IVD tissues was detected by immunohistochemical staining. Besides gene expression of IL-23, IL-17, IL-6, IL-1β, and TNF-α was also evaluated by reverse transcription polymerase chain reaction (RT-PCR).

RESULTS

The results showed that the R group was more degenerated than the other two groups and NC group showed the least degenerated performance; stronger positive IL-23 expression was observed in herniated IVDs, especially in the R group. Meanwhile, higher gene expression of IL-23, IL-17, IL-6, IL-1β, and TNF-α was found in the tissues from LDH patients and a positive correlation between IL-17 and IL-23 gene expression was also observed.

CONCLUSIONS

Taken all above results together, it may be deduced that higher expression of IL-23 may contribute to the deterioration of IVDs through the IL-23/IL-17 pathway.

IL-17A enhances ADAMTS-7 expression through regulation of TNF-α in human nucleus pulposus cells

ADMATS-7 is known to play an important role in the pathogenesis of various diseases, including cartilaginous diseases. IL-17A is an inflammatory cytokine detected in degenerative disc tissues. However, the interplay between IL-17A and ADMATS-7 in human disc degeneration is still unknown. Samples collected from 50 patients were divided into three groups according to MRI degeneration grading system score. Immunohistochemistry, RT-PCR and western Blotting were used to investigate the expression of ADAMTS-7 in NP tissues. Furthermore, a rat disc degeneration model was established, and the expression level of ADAMTS-7 was assayed using immunohistochemistry, RT-PCR and western Blotting. The human NP cells were cultured in the presence and absence of IL-17A stimulation. RNA extracts were collected, and real-time PCR was performed to determine the expression of ADAMTS-7. Moreover, ADAMTS-7 concentrations were detected in human NP cell culture supernatants by ELISA. After culturing NP cells with IL-17A (with or without Etanercept), ADAMTS-7 levels were detected in each group. ADAMTS-7 expression was dramatically elevated in both human and rat degenerative NP tissues compared with normal controls. The RT-PCR and ELISA results revealed that IL-17A could enhance the production of ADAMTS-7, while ADAMTS-7 expression dramatically decreased in the IL-17A + Etanercept group in comparison to the IL-17A alone group. Our results indicate the presence of ADAMTS-7 in human NP cells and imply its potential role in disc degeneration. Additionally, our results indicate that IL-17A induced ADAMTS-7 expression via TNF-α, which may form a molecular axis in human NP cells.

Role of interleukin-17 in chondrocytes of herniated intervertebral lumbar discs

Lumbar disc herniation (LDH) is a common cause of lumbosacral radiculopathy. An autoimmune response to a herniated nucleus pulposus (NP) has been suggested to play an important role in the initiation of radiculopathy. Interleukin-17 (IL-17) is a cytokine associated with inflammation and autoimmunity. The presence of IL-17 has been studied in patients with LDH; however, extensive investigation into the expression of IL-17 in different disc pathologies of LDH has not yet been conducted. The aim of the present study was to investigate the role of neovascularization and hypertrophic chondrocytes in herniated intervertebral lumbar discs. Fifty-two intervertebral lumbar disc specimens were extracted from 46 patients with LDH and were subsequently classified as either contained or non-contained disc herniation (CDH and NCDH, respectively). The specimens were stained with hematoxylin and eosin or toluidine blue, or were immunostained with polyclonal antibodies to IL-17 using the streptavidin-peroxidase method. The neovascular tissue and staining results were graded to establish the histological differences between the two herniation types. The intervertebral discs (IVDs) obtained from patients with NCDH showed significantly more neovascularization and granulation tissue than the discs obtained from patients with CDH (P<0.05). Furthermore, hypertrophic chondrocytes were more abundant in the NCDH specimens than in the CDH specimens (P<0.05). Similarly, the number of IL-17-immunoreactive cells was significantly higher in the NCDH specimens than that in the CDH specimens (P<0.01). In conclusion, local inflammation and autoreactive immune activation may play an important role in the pathogenesis of LDH. These results also suggest a role of chondrocytes in the repair of herniated IVDs.

Participation of interleukin 17A in neuroimmune interactions

Inflammation involving the helper T cell 17 (Th17) subset of lymphocytes has been implicated in a number of diseases that affect the nervous system. As the canonical cytokine of Th17 cells, interleukin 17A (IL-17A) is thought to contribute to these neuroimmune interactions. The main receptor for IL-17A is expressed in many neural tissues. IL-17A has direct effects on neurons but can also impact neural function via signaling to satellite cells and immune cells. In the central nervous system, IL-17A has been associated with neuropathology in multiple sclerosis, epilepsy syndromes and ischemic brain injury. Effects of IL-17A at the level of dorsal root ganglia and the spinal cord may contribute to enhanced nociception during neuropathic and inflammatory pain. Finally, IL-17A plays a role in sympathetic axon growth and regeneration of damaged axons that innervate the cornea. Given the widespread effects of IL-17A on neural tissues, it will be important to determine whether selectively mitigating the damaging effects of this cytokine while augmenting its beneficial effects is a possible strategy to treat inflammatory damage to the nervous system.

Disrupted TH17/Treg balance in patients with chronic low back pain

Chronic low back pain (CLBP) is a leading cause of disability and costs in health care systems worldwide. Despite extensive research, the exact pathogenesis of CLBP, particularly the individual risk of chronification remains unclear. To investigate a possible role of the adaptive immune system in the pathophysiology of CLBP, we analyzed T cell related cytokine profiles, T cell related mRNA expression patterns and the distribution of T cell subsets in 37 patients suffering from nonspecific CLBP before and after multimodal therapy in comparison to 25 healthy controls. Serum patterns of marker cytokines were analyzed by Luminex technology, mRNA expression of cytokines and specific transcription factors was measured by real-time PCR, and distribution of TH1-, TH2-, TH17- and regulatory T cell (Tregs) subsets was determined by multicolor flow cytometry. We found that CLBP patients exhibit an increased number of anti-inflammatory Tregs, while pro-inflammatory TH17 cells are decreased, resulting in an altered TH17/Treg ratio. Accordingly, FoxP3 and TGF-β-mRNA expression was elevated, while expression of IL-23 was reduced. Serum cytokine analyses proved to be unsuitable to monitor the adaptive immune response in CLBP patients. We further show that even after successful therapy with lasting reduction of pain, T cell subset patterns remained altered after a follow-up period of 6 months. These findings suggest an involvement of TH17/Treg cells in the pathogenesis of CLBP and emphasize the importance of these cells in the crosstalk of pain and immune response.

Trial Registration

German Clinical Trial Register: Registration Trial DRKS00005954.

Th17 cell frequency and IL-17 concentration correlate with pre- and postoperative pain sensation in patients with intervertebral disk degeneration

Numerous studies have revealed the presence of T helper 17 (Th17) cells in pathologic intervertebral disk (IVD) tissues and the contribution of Th17-associated cytokines to the development of this disease. However, the pre- and postoperative changes in the proportion of Th17 cells and the concentration of IL-17 in the peripheral blood of patients with IVD degeneration are not clear. The levels of Th17 frequency and the interleukin-17 (IL-17) concentration in peripheral blood from patients and volunteers were examined by flow cytometry and by enzyme-linked immunosorbent assay (ELISA), respectively. The clinical results were evaluated using the visual analogue scale (VAS). These results were subjected to a correlation analysis. Compared with the normal controls, the proportion of Th17 cells and the concentration of IL-17 were significantly increased preoperatively in patients with IVD degeneration. Postoperatively, the levels of Th17 cells and the expression of IL-17 were dramatically decreased. The correlation analysis of the VAS pain scores, Th17 cell frequency, and IL-17 concentration, including the pre- and postoperative levels and the changes induced by the surgery, revealed a positive correlation. The authors' results explain the contribution of Th17 cells and IL-17 to the pain sensation experienced by patients with IVD degeneration. These 2 factors may be good indicators for the evaluation of the surgical outcome of patients with lumbar disk herniation.

Transcript levels of major interleukins in relation to the clinicopathological profile of patients with tuberculous intervertebral discs and healthy controls

Objectives

The purpose of the present study was to simultaneously examine the transcript levels of a large number of interleukins (ILs; IL-9, IL-10, IL-12, IL-13, IL-16, IL-17, IL-18, IL-26, and IL-27) and investigate their correlation with the clinicopathological profiles of patients with tuberculous intervertebral discs.

Methods

Clinical data were collected from 150 patients participating in the study from January 2013 to December 2013. mRNA expression levels in 70 tuberculous, 70 herniated, and 10 control intervertebral disc specimens were determined by real-time polymerase chain reaction.

Results

IL-10, IL-16, IL-17, IL-18, and IL-27 displayed stronger expression in tuberculous spinal disc tissue than in normal intervertebral disc tissue (P<0.05). Our results illustrated multiple correlations among IL-10, IL-16, IL-17, IL-18, and IL-27 mRNA expression in tuberculous samples. Smoking habits were found to have a positive correlation with IL-17 transcript levels and a negative correlation with IL-10 transcript levels (P<0.05). Pain intensity, symptom duration, C-reactive protein levels, and the erythrocyte sedimentation rate exhibited multiple correlations with the transcript levels of several ILs (P<0.05).

Conclusions

The experimental data imply a double-sided effect on the activity of ILs in tuberculous spinal intervertebral discs, suggesting that they may be involved in intervertebral discs destruction. Our findings also suggest that smoking may affect the intervertebral discs destruction process of spinal tuberculosis. However, further studies are necessary to elucidate the exact role of ILs in the intervertebral discs destruction process of spinal tuberculosis.