Correlation between radiculalgia and counts of T lymphocyte subsets in the peripheral blood of patients with lumbar disc herniation

Causal relationship between the blood immune cells and intervertebral disc degeneration: univariable, bidirectional and multivariable Mendelian randomization

Background

Intervertebral disc degeneration (IVDD) is a prominent contributor to chronic low back pain, impacting millions of individuals annually. Current research on disc degeneration is placing a growing emphasis on the role of the immune system in this process. Nevertheless, the precise relationship between immunity and disc degeneration remains to be fully elucidated.

Method

We obtained GWAS data for immune cells from the latest summary-level GWAS, including 6,620 individuals from Sardinian and 746,667 individuals from five global populations. Summary results for IVDD were sourced from the FinnGen consortium, comprising 20,001 cases and 164,682 controls. We conducted a comprehensive univariable Mendelian randomization (MR) analysis to explore the potential causal relationship between immune cells and IVDD. Primary estimation was carried out using Inverse-Variance Weighting (IVW). To ensure robustness, we employed additional MR methods such as MR-Egger, Weighted Median, Weighted Mode, and Simple Mode. Various tests were employed to assess pleiotropy and heterogeneity, including the Cochran Q test, leave-one-out test, MR-Egger intercept analysis and MR-PRESSO test. To account for potential confounding factors among the immune cells, we conducted a multivariable MR analysis. Finally, we investigated the possibility of a reverse association between immune cells and IVDD through bidirectional MR.

Result

In total, our study identified 15 immune cells significantly associated with IVDD through univariable MR. Among these, 9 immune cell types were indicated as potential contributors to IVDD, while 6 were found to have protective effects. Importantly, we observed no evidence of heterogeneity or pleiotropy, signifying the robustness of our results. To mitigate confounding among immune cells, we utilized multivariable MR, leading to the discovery that only 9 immune cell types exerted independent effects on IVDD. These encompassed 7 as risk factors and 2 as protective factors. Additionally, our analysis revealed a bidirectional causal relationship between CD39+ CD4+ T cell %CD4+ T cell and IVDD.

Conclusion

Our findings suggest a connection between immune cells and the risk of IVDD, shedding light on potential therapeutic avenues for modulating immune cell function in individuals with IVDD. However, the specific underlying mechanisms warrant further investigation in future experiments.

A comparative study on the clinical efficacy of percutaneous endoscopic lumbar discectomy and conventional open surgery in the treatment of lumbar disc herniation

Objective

To analyze the efficacy of single-channel percutaneous endoscopic lumbar discectomy (PELD) and conventional open surgery in the treatment of lumbar disc herniation (LDH).

Methods

This is a retrospective study. A total of 66 patients with LDH admitted to Tianjin Medical University from June 2017 to June 2018 were divided into two groups: the observation group (single-channel PELD) and the control group (posterior lumbar interbody fusion), with 33 cases in each group. The two groups were compared in terms of visual analogue scale(VAS), oswestry disability index (ODI), Japanese Orthopaedic Association Score(JOA), perioperative indicators, clinical efficacy, postoperative complications, changes in inflammatory factors and serum T lymphocyte subsets.

Results

The operation time, incision length, intraoperative blood loss, time in bed, hospital stay in the observation group were all lower than those in the control group. At 7d after treatment, the improvement of ODI, VAS and JOA in the observation group were better than that in the control group. At the last follow-up, there was no significant difference in Cobb angle and lumbar lordosis angle between the two groups. The levels of serum IL-1, IL-6 and TNF-α in the observation group were lower than those in the control group. The degree of reduction of serum CD3+ and CD4+ in the observation group were higher than those in the control group. And the level of elevation of CD8+ in the observation group was lower than that in the control group. Moreover, there was no significant difference in CD4+/CD8+ level between the two groups. The excellent rate of surgical results in the observation group was higher than that in the control group. Complications occurred in both groups, with no significant difference between the two groups.

Conclusions

Single-channel PELD can achieve superior clinical efficacy over conventional open surgery in the treatment of LDH.

Potential blood markers as screening tools for subjects with low back pain: an age- and gender-matched cross-sectional analysis

BACKGROUND

Mechanical and inflammatory factors were suggested as the causes of spine degeneration and low back pain (LBP). Previous studies partly reported the association of LBP with inflammation. However, none of them compared patients with LBP and asymptomatic subjects in terms of complete blood count and inflammatory markers in detail. We aimed to analyze the association of serum white blood cell (WBC) count, C-reactive protein (CRP), and erythrocyte sedimentation rate (ESR) with chronic LBP by comparing the patients with chronic LBP and age- and gender-matched asymptomatic subjects.

METHODS

Lumbar intervertebral disc degeneration and vertebral end-plates were evaluated using Pfirrmann grading and Modic classification on lumbar spine magnetic resonance images, respectively. Serum WBC counts, CRP levels, and ESRs were recorded from chart reviews.

RESULTS

We included 147 patients with chronic LBP and 101 asymptomatic subjects. Patients with chronic LBP had significantly higher serum neutrophil, monocyte, and basophil counts, higher neutrophil-to-lymphocyte ratio, higher ESR, and lower serum CRP levels compared to the asymptomatic subjects. Serum monocyte and basophil cell counts and ESR were the most remarkable predictive factors for chronic LBP, severe IVDD, and Modic changes. Higher serum monocyte and basophil cell counts and higher serum ESR above cut-off values of 0.42 × 103/μL, 0.025 × 103/μL, and 3.5 mm/hour could be used as screening tools for subjects with persistent LBP in primary care.

DISCUSSION

Higher serum monocyte and basophil counts and serum ESR above new cut-off values should highlight the need to obtain early spinal imaging to prevent chronicity in patients with LBP.

Engineered Human Intervertebral Disc Model Inducing Degenerative Microglial Proinflammation

Degeneration of the intervertebral disc (IVD) is a major contributor to low back pain (LBP). IVD degeneration is characterized by abnormal production of inflammatory cytokines secreted by IVD cells. Although the underlying molecular mechanisms of LBP have not been elucidated, increasing evidence suggests that LBP is associated particularly with microglia in IVD tissues and the peridiscal space, aggravating the cascade of degenerative events. In this study, we implemented our microfluidic chemotaxis platform to investigate microglial inflammation in response to our reconstituted degenerative IVD models. The IVD models were constructed by stimulating human nucleus pulposus (NP) cells with interleukin-1β and producing interleukin-6 (129.93 folds), interleukin-8 (18.31 folds), C-C motif chemokine ligand-2 (CCL-2) (6.12 folds), and CCL-5 (5.68 folds). We measured microglial chemotaxis (p < 0.05) toward the conditioned media of the IVD models. In addition, we observed considerable activation of neurodegenerative and deactivation of protective microglia via upregulated expression of CD11b (p < 0.001) and down-regulation of CD206 protein (p < 0.001) by soluble factors from IVD models. This, in turn, enhances the inflammatory milieu in IVD tissues, causing matrix degradation and cellular damage. Our findings indicate that degenerative IVD may induce degenerative microglial proinflammation, leading to LBP development.

Regenerative Role of T Cells in Nerve Repair and Functional Recovery

The immune system is essential in the process of nerve repair after injury. Successful modulation of the immune response is regarded as an effective approach to improving treatment outcomes. T cells play an important role in the immune response of the nervous system, and their beneficial roles in promoting regeneration have been increasingly recognized. However, the diversity of T-cell subsets also delivers both neuroprotective and neurodegenerative functions. Therefore, this review mainly discusses the beneficial impact of T-cell subsets in the repair of both peripheral nervous system and central nervous system injuries and introduces studies on various therapies based on T-cell regulation. Further discoveries in T-cell mechanisms and multifunctional biomaterials will provide novel strategies for nerve regeneration.

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.

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.

Effects of photobiomodulation on annulus fibrosus cells derived from degenerative disc disease patients exposed to microvascular endothelial cells conditioned medium

Intervertebral disc (IVD) degeneration with chronic low back pain is associated with neo-vascularisation into the deeper IVD regions. During this process, endothelial cells (ECs), which are primarily responsible for angiogenesis, interact with the adjacent annulus fibrosus (AF) cells, which are the first line of defence against the invasion of vascular structures into deeper IVD regions. However, the accumulation of inflammatory and catabolic enzymes that results from this interaction promotes matrix degradation and an inflammatory response. Thus, regulating the production of these mediators and catabolic enzymes could ameliorate IVD degeneration. Photobiomodulation (PBM) therapy is a non-invasive stimulation known to have biologically beneficial effects on wound healing, tissue repair, and inflammation. Here, we examined the effects of PBM, administered at various wavelengths (645, 525, and 465 nm) and doses (16, 32, and 64 J/cm²), on EC-stimulated human AF cells. Our results show that PBM selectively inhibited the EC-mediated production of inflammatory mediators, catabolic enzymes, and neurotrophins by human AF cells in a dose- and wavelength-dependent manner. These results suggest that PBM could be a superior and advanced treatment strategy for IVD degeneration.

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.

Systemic Inflammatory and Th17 Immune Activation among Patients Treated for Lumbar Radiculopathy Exceeds that of Patients Treated for Persistent Postoperative Neuropathic Pain

BACKGROUND

The pathophysiology of lumbar radiculopathy includes both mechanical compression and biochemical irritation of apposed neural elements. Inflammatory and immune cytokines have been implicated, induced by systemic exposure of immune-privileged intervertebral disc tissue. Surgical intervention provides improved symptoms and quality of life, but persistent postoperative neuropathic pain (PPNP) afflicts a significant fraction of patients.

OBJECTIVE

To compare the inflammatory and immune phenotypes among patients undergoing structural surgery for lumbar radiculopathy and spinal cord stimulation for neuropathic pain.

METHODS

Consecutive patients undergoing surgical intervention for lumbar radiculopathy or neuropathic pain were studied. Demographic data included age, gender, and VAS and neuropathic pain scores. Serum was evaluated for cytokine levels (IL-6, Il-17, TNF-α) and cellular content [white blood cell (WBC)/differential, lymphocyte subtypes]. The primary analysis differentiated molecular and cellular profiles between radiculopathy and neuropathic pain patients. Subgroup analysis within the surgical radiculopathy population compared those patients achieving relief of symptoms and those with PPNP.

RESULTS

Heightened IL-6, Il-17, and TNF-α levels were observed for the lumbar radiculopathy group compared with the neuropathic pain group. This was complemented by higher WBC count and a greater fraction of Th17 lymphocytes among radiculopathy patients. In the lumbar discectomy subgroup, pain relief was seen among patients with preoperatively elevated IL-17 levels. Those patients with PPNP refractory to surgical discectomy exhibited normal cytokine levels.

CONCLUSION

Differences in Th17 immune activation are seen among radiculopathy and neuropathic pain patients. These cellular and molecular profiles may be translated into biomarkers to improve patient selection for structural spine surgery.

Correlation of Circulating T Lymphocytes and Intracranial Hypertension in Intracerebral Hemorrhage

BACKGROUND

The close correlation between intracerebral pressure (ICP) and immunologic responses has been well described, but the role of T lymphocytes in this process remains unknown. This study targeted the relationship of circulating T lymphocytes and ICP in patients with intracerebral hemorrhage (ICH).

METHODS

Between October 2015 and October 2016, consecutive patients age 18-65 years with ICH were enrolled. ICP values were recorded hourly for 5 days, and the screened patients were divided into 2 groups based on ICP: the elevated ICP group (ICP >20 mmHg) and normal ICP group (ICP ≤20 mmHg). Peripheral blood was collected on admission and T lymphocyte subpopulations were analyzed by flow cytometry. Glasgow Coma Scale score on admission and Glasgow Outcome Scale (GOS) score at 30 days after ICH were analyzed.

RESULTS

A total of 44 patients were enrolled, including 18 patients in the elevated ICP group and 26 in the normal ICP group. Both CD3⁺ and CD4⁺ T lymphocyte counts were higher in the elevated ICP group (P = 0.004 and 0.000, respectively). The CD8⁺ T lymphocyte count was not significantly different between the 2 groups (P = 0.751). There were correlation trends between the maximum ICP value and CD3⁺ lymphocyte count (P = 0.003), CD4⁺ T lymphocyte count (P = 0.000), and the CD4⁺/CD8⁺ T lymphocyte ratio (P = 0.000). The area under the curve (AUC) of CD4⁺/CD8⁺ T lymphocyte ratio was the largest among them (P = 0.011 and 0.033), with a significant cutoff value and good specificity and sensitivity. There was a close correlation between the CD4⁺/CD8⁺ T lymphocyte ratio and the 30-day GOS score (P = 0.003, AUC = 0.812).

CONCLUSIONS

The CD4⁺/CD8⁺ T lymphocyte ratio may be a valuable indicator for predicting postoperative ICP and the short-term prognosis after ICH.

Immune cell distribution and immunoglobulin levels change following sciatic nerve injury in a rat model

OBJECTIVES

To investigate the systemic and local immune status of two surgical rat models of sciatic nerve injury, a crushed sciatic nerve, and a sciatic nerve transection.

MATERIALS AND METHODS

Twenty-four adult male Sprague-Dawley rats were randomly divided into three groups: sham-operation (control group), sciatic nerve crush, and sciatic nerve transaction. Sciatic nerve surgery was performed. The percentage of CD4(+) cells and the CD4(+)/CD8+ratio were determined by flow cytometry. Serum IgM and IgG levels were analyzed by ELISA. T-cells (CD3) and macrophages (CD68) in sciatic nerve tissue sections were identified through immunohistochemistry.

RESULTS

Compared to sham-operated controls, in rats that underwent nerve injury, the percentage of CD4(+) cells and the CD4(+)/CD8(+) ratio in the peripheral blood were significantly decreased 7 days after surgery, serum IgM levels were increased 14 days after surgery, and serum IgG levels were increased 21 days after surgery. There were a large number of CD3(+) cells and a small number of CD68(+) cells in sciatic nerve tissue sections 21 days after surgery, indicating T-cell and macrophage activation and infiltration. Local IgG deposition was also detected at the nerve injury site 21 days after surgery.

CONCLUSION

Rat humoral and cellular immune status changed following sciatic nerve injury, particularly with regard to the cellular immune response at the nerve injury site.

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.

Role of cytokines in intervertebral disc degeneration: pain and disc content

Degeneration of the intervertebral discs (IVDs) is a major contributor to back, neck and radicular pain. IVD degeneration is characterized by increases in levels of the proinflammatory cytokines TNF, IL-1α, IL-1β, IL-6 and IL-17 secreted by the IVD cells; these cytokines promote extracellular matrix degradation, chemokine production and changes in IVD cell phenotype. The resulting imbalance in catabolic and anabolic responses leads to the degeneration of IVD tissues, as well as disc herniation and radicular pain. The release of chemokines from degenerating discs promotes the infiltration and activation of immune cells, further amplifying the inflammatory cascade. Leukocyte migration into the IVD is accompanied by the appearance of microvasculature tissue and nerve fibres. Furthermore, neurogenic factors, generated by both disc and immune cells, induce expression of pain-associated cation channels in the dorsal root ganglion. Depolarization of these ion channels is likely to promote discogenic and radicular pain, and reinforce the cytokine-mediated degenerative cascade. Taken together, an enhanced understanding of the contribution of cytokines and immune cells to these catabolic, angiogenic and nociceptive processes could provide new targets for the treatment of symptomatic disc disease. In this Review, the role of key inflammatory cytokines during each of the individual phases of degenerative disc disease, as well as the outcomes of major clinical studies aimed at blocking cytokine function, are discussed.

A review of the role of epidural percutaneous adhesiolysis

SUMMARY Low back and leg pain can arise for a variety reasons, including epidural scarring caused by post lumbar surgery syndrome, infection or bleeding. Treatment options for low back and/or leg pain caused by epidural scarring include conservative approaches, such as physical therapy and medication management, and procedures, such as epidural steroid injections. Despite appropriate treatment, pain can persist in these patients. Surgery is often not an option for patients whose pain is caused by scarring. Percutaneous adhesiolysis is a minimally invasive technique, which is effective in treating refractory low back and leg pain arising from epidural scarring. It involves the use of a spring-wound, shear-resistant catheter, ideally placed in the ventrolateral aspect of the epidural space for the lysis of adhesions, allowing medications to reach the involved nerve and removing compression of the nerve. After mechanical lysis of adhesions, relatively large volumes of local anesthetic, saline, steroid and radiopaque contrast material are injected. Either hypertonic or normal saline may be used, along with hyaluronidase. After the procedure, the patient should perform exercises to stretch the nerve roots. While this has been studied as a caudal procedure, thoracic and cervical procedures have also been described, using both transforaminal and interlaminar approaches. With trained practitioners, complications are minimal. The effectiveness of the procedure has been documented by high-quality randomized controlled trials and observational studies for both postlumbar surgery syndrome and spinal stenosis.