Anti-nociceptive effect of IL-12p40 in a rat model of neuropathic pain

Study on the correlation between IL-12p70, IL-17A and migraine in children

Objective

To compare the serum levels of 12 cytokines in migraine group, encephalitis with headache symptoms group, pneumonia without headache symptoms group and migraine subgroups to explore the cytokines associated with migraine in children and their levels.

Methods

A total of 44 children with migraine, 27 children in the encephalitis group with headache symptoms and 44 children in the pneumonia group without headache symptoms were selected from January 2022 to August 2023 in Hebei Children's Hospital. They were all tested for serum cytokines by immunofluorescence assay. The migraine group was further divided into subgroups according to different age, gender, course of disease, and presence of coinfection. The differences of serum cytokine levels among the above groups were compared, and the correlation analysis was carried out.

Results

Except IL-5, there were no significant differences in the expression levels of other 11 inflammatory cytokines between migraine subgroups. Compared with encephalitis with headache symptoms group and pneumonia without headache symptoms group the serum levels of IL-4, TNF-α, IL-17A, and IL-12p70 were higher in migraine group than in pneumonia group, and the levels of IL-12p70 were higher than those in encephalitis group (p < 0.05). An increase in serum IL-12p70 (OR = 1.267, 95%CI 1.054-1.523, p = 0.012) and IL-17A (OR = 1.066, 95%CI 1.016-1.119, p = 0.010) levels had a significant effect on migraine.

Conclusion

Elevated serum levels of IL-12p70 and IL-17A may increase the risk of migraine in children, which has certain diagnostic and predictive value.

Applying Serum Cytokine Levels to Predict Pain Severity in Cancer Patients

Background and Aim

Cancers originating in the breast, lung and prostate often metastasize to the bone, frequently resulting in cancer-induced bone pain that can be challenging to manage despite conventional analgesic therapy. This exploratory study’s aim was to identify potential biomarkers associated with cancer-induced pain by examining a sample population of breast cancer patients undergoing bisphosphonate therapy.

Methods

A secondary analysis of the primary study was performed to quantify serum cytokine levels for correlation to pain scores. Cytokines with statistically significant correlations were then input into a stepwise regression analysis to generate a predictive equation for a patient’s pain severity. In an effort to find additional potential biomarkers, correlation analysis was performed between these factors and a more comprehensive panel of cytokines and chemokines from breast, lung, and prostate cancer patients.

Results

Statistical analysis identified nine cytokines (GM-CSF, IFNγ, IL-1β, IL-2, IL-4, IL-5, IL-12p70, IL-17A, and IL-23) that had significant negative correlations with pain scores and they could best predict pain severity through a predictive equation generated for this specific evaluation. After performing a correlation analysis between these factors and a larger panel of cytokines and chemokines, samples from breast, lung and prostate patients showed distinct correlation profiles, highlighting the clinical challenge of applying pain-associated cytokines related to more defined nociceptive states, such as arthritis, to a cancer pain state.

Conclusion

Exploratory analyses such as the ones presented here will be a beneficial tool to expand insights into potential cancer-specific nociceptive mechanisms and to develop novel therapeutics.

Effect of interscalene nerve block on the inflammatory response in shoulder surgery: a randomized trial

BACKGROUND

Comparing techniques of general anesthesia and regional anesthesia in arthroscopic shoulder surgery, some studies have shown differences in the intensity of immediate postoperative pain and neuroendocrine response, but the inflammatory response when using balanced general anesthesia (BGA) vs. an ultrasound-guided (USG) single-dose interscalene block (SDIB) has not been compared.

MATERIALS AND METHODS

In a single-center, prospective, randomized clinical trial, the inflammatory response of 2 groups of 10 patients scheduled to undergo arthroscopic shoulder surgery was evaluated through measurement of a panel of cytokines that act on cells of the adaptive immune response to promote or inhibit inflammation, chemokines involved in chemotaxis, the erythrocyte sedimentation rate (ESR), the high-sensitivity C-reactive protein (CRP) level, and the white blood cell (WBC) count in 3 blood samples (before anesthesia, immediately postoperatively, and 24 hours postoperatively) with 2 types of anesthesia (BGA vs. USG SDIB). Postoperative pain intensity (immediately, at 12 hours, and at 24 hours) was also assessed.

RESULTS

The ESR and CRP level increased significantly at 24 hours after surgery; however, the increase in ESR (P < .0001) and CRP level (P < .0001) was lower in the USG SDIB group. Significant increases in the levels of soluble interleukin 2 receptor α (P = .022) and interleukin 12p40 (P = .016) occurred in the immediate postoperative period in the USG SDIB group. Immediate postoperative pain showed a significant increase (P < .001) in the BGA group.

CONCLUSIONS

In arthroscopic shoulder surgery, the use of a USG SDIB compared with the use of BGA is possibly associated with improved pain control in the immediate postoperative period and lower immunosuppression, even at 24 hours after surgery.

Identification of candidate genes and miRNAs associated with neuropathic pain induced by spared nerve injury

Neuropathic pain (NP) is a complex, chronic pain condition caused by injury or dysfunction affecting the somatosensory nervous system. This study aimed to identify crucial genes and miRNAs involved in NP. Microarray data (access number GSE91396) were downloaded from the Gene Expression Omnibus (GEO). Murine RNA-seq samples from three brain regions [nucleus accumbens, (NAc); medial prefrontal cortex, (mPFC) and periaqueductal gray, (PAG)] were compared between the spared nerve injury (SNI) model and a sham surgery. After data normalization, differentially expressed RNAs were screened using the limma package and functional enrichment analysis was performed with Database for Annotation, Visualization and Integrated Discovery. The microRNA (miRNA/miR)-mRNA regulatory network and miRNA-target gene-pathway regulatory network were constructed using Cytoscape software. A total of 2,776 differentially expressed RNAs (219 miRNAs and 2,557 mRNAs) were identified in the SNI model compared with the sham surgery group. A total of two important modules (red and turquoise module) were found to be related to NP using weighed gene co-expression network analysis (WGCNA) for the 2,325 common differentially expressed RNAs in three brain regions. The differentially expressed genes (DEGs) in the miRNA-mRNA regulatory network were significantly enriched in 21 Gene Ontology terms and five pathways. A total of four important DEGs (CXCR2, IL12B, TNFSF8 and GRK1) and five miRNAs (miR-208a-5p, miR-7688-3p, miR-344f-3p, miR-135b-3p and miR-135a-2-3p) were revealed according to the miRNA-target gene-pathway regulatory network to be related to NP. Four important DEGs (CXCR2, IL12B, TNFSF8 and GRK1) and five miRNAs (miR-208a-5p, miR-7688-3p, miR-344f-3p, miR-135b-3p and miR-135a-2-3p) were differentially expressed in SNI, indicating their plausible roles in NP pathogenesis.

Effect of Pregabalin and Diclofenac on tactile allodynia, mechanical hyperalgesia and pro inflammatory cytokine levels (IL-6, IL-1β) induced by chronic constriction injury of the infraorbital nerve in rats

The present study evaluated the effects of systemic pregabalin (PG) and diclofenac (Dic) on neuropathic orofacial pain induced by chronic constriction injury (CCI) of the infraorbital nerve (ION) and on the pro-inflammatory cytokines levels in the affected nerve. Fifty-four rats underwent left infra orbital nerve CCI, and 7 days after the procedure as the pain developed, the rats were randomly assigned to one of the treatment groups: PG 300, 30 or 10 mg/kg, Dic 10, 5 or 1 mg/kg or saline group (Sal) (n/group = 8). Addiitonal 8 rats served as naïve control group. Tactile-allodynia and Mechano-hyperalgesia were tested before the surgical procedure and at days 7, 8, and 9 postoperatively. On the 9th day, the rats were euthanized and the affected and contralateral sciatic nerves were harvested to assess IL-6 and IL-1β nerve levels employing enzyme linked immunosorbent assay (ELISA). Daily injection of PG (all doses) significantly reduced tactile-allodynia and mechano-hyperalgesia (p < .05) while Dic did not. On the 9th day, the ipsilateral nerve IL-6 levels were significantly decreased (p < .05) in the PG and DIC groups compared to the Sal group. IL-1β levels demonstrated a significant reduction (p < .05) in the PG group when compared to saline. These results suggest that PG but not Dic may be effective in reducing neuropathic orofacial pain. The mechanisms of action may be associated to some extent with reduction in IL-1β levels in the affected nerve.

Interleukin-8 levels in rat models of nerve damage and neuropathic pain

Interleukin-8 (IL-8) is a pro-inflammatory cytokine that has been shown to play a role in inflammatory and autoimmune disorders. The objective of the present study was to assess the levels of IL-8 in rat serum, dorsal root ganglion (DRG) and the sciatic nerve following four different forms of sciatic nerve injury. The models used to induce the injury included partial sciatic ligation (PSL), chronic constriction injury (CCI), perineural inflammation (neuritis) and complete sciatic transection (CST). Mechanical and thermal hyperalgesia were detected by measuring withdrawal responses from a mechanical stimulus and withdrawal latency from thermal stimulation. Enzyme-linked immunosorbent assays (ELISA) was used to assess the IL-8 levels in the affected and contralateral sciatic nerves. Rats exposed to PSL and neuritis developed significant nociceptive response (mechanical and thermal hyperalgesia) in the affected side at three days post-surgery whereas the CCI group at eight days post-surgery. No mechanical or thermal hyperalgesia was observed in rats exposed to CST at either three or eight days postsurgery. Additionally, IL-8 levels were significantly increased in the injured sciatic nerve at 3 and 8days following PSL and neuritis as well as at 8days following CCI when compared to naïve animals. A significant up regulation of IL-8 levels was observed in the ipsilateral DRG at 3 and 8days following CST compared to naïve animals. The serum IL-8 levels remained unchanged in all models of nerve damage. The results of this study suggest that IL-8's role in the neuropathic pain etiology may be specific to nerve injury type.

Exercise-Induced Change in Plasma IL-12p70 Is Linked to Migraine Prevention and Anxiolytic Effects in Treatment-Naïve Women: A Randomized Controlled Trial

OBJECTIVE

To conduct a randomized controlled trial to evaluate the effect of a 12-week aerobic exercise program for migraine prevention, plasma cytokines concentrations (TNF-α, interleukin [IL]-1β, IL-6, IL-8, IL-10, and IL-12p70), and anxiety in women with migraine.

METHODS

Women with episodic migraine (ICHD-II), aged between 20 and 50 years, who had never taken any prophylactic medication, and were physically inactive in the past 12 months were recruited from the university's hospital and a tertiary headache clinic between March 2012 and March 2015. Migraine attacks were recorded in headache diaries, cytokines were quantified by flow cytometry, and anxiety was assessed by the 7-item General Anxiety Disorder (GAD-7) scale. Blood sampling and psychometric interviews were undertaken on headache-free days.

RESULTS

Twenty participants ([mean ± SD] age 33.8 ± 10.5; BMI 26 ± 5.2) were randomly assigned and received intervention ("trained": n = 10) or entered on a waitlist ("inactive": n = 10). There were no differences between groups regarding patients' characteristics and baseline data. Days with migraine (p = 0.001), IL-12p70 levels (p = 0.036), and GAD-7 score (p = 0.034) were significantly reduced in the trained group after the intervention period, but there were no significant changes in these variables in the inactive group. There was no change in the levels of the other cytokines in either group. There were positive correlations between a reduction in IL-12p70 level and a reduction in the number of days with migraine (R2 = 0.19, p = 0.045), and GAD-7 score (R2 = 0.53, p < 0.001).

CONCLUSION

The clinical and psychological therapeutic effects of aerobic exercise in treatment-naïve women with migraine may involve the downregulation of IL-12p70.

Contemporary views on inflammatory pain mechanisms: TRPing over innate and microglial pathways

Tissue injury, whether by trauma, surgical intervention, metabolic dysfunction, ischemia, or infection, evokes a complex cellular response (inflammation) that is associated with painful hyperalgesic states. Although in the acute stages it is necessary for protective reflexes and wound healing, inflammation may persist well beyond the need for tissue repair or survival. Prolonged inflammation may well represent the greatest challenge mammalian organisms face, as it can lead to chronic painful conditions, organ dysfunction, morbidity, and death. The complexity of the inflammatory response reflects not only the inciting event (infection, trauma, surgery, cancer, or autoimmune) but also the involvement of heterogeneous cell types including neuronal (primary afferents, sensory ganglion, and spinal cord), non-neuronal (endothelial, keratinocytes, epithelial, and fibroblasts), and immune cells. In this commentary, we will examine 1.) the expression and regulation of two members of the transient receptor potential family in primary afferent nociceptors and their activation/regulation by products of inflammation, 2.) the role of innate immune pathways that drive inflammation, and 3.) the central nervous system’s response to injury with a focus on the activation of spinal microglia driving painful hyperalgesic states.

Salmon-derived thrombin inhibits development of chronic pain through an endothelial barrier protective mechanism dependent on APC

Many neurological disorders are initiated by blood-brain barrier breakdown, which potentiates spinal neuroinflammation and neurodegeneration. Peripheral neuropathic injuries are known to disrupt the blood-spinal cord barrier (BSCB) and to potentiate inflammation. But, it is not known whether BSCB breakdown facilitates pain development. In this study, a neural compression model in the rat was used to evaluate relationships among BSCB permeability, inflammation and pain-related behaviors. BSCB permeability increases transiently only after injury that induces mechanical hyperalgesia, which correlates with serum concentrations of pro-inflammatory cytokines, IL-7, IL-12, IL-1α and TNF-α. Mammalian thrombin dually regulates vascular permeability through PAR1 and activated protein C (APC). Since thrombin protects vascular integrity through APC, directing its affinity towards protein C, while still promoting coagulation, might be an ideal treatment for BSCB-disrupting disorders. Salmon thrombin, which prevents the development of mechanical allodynia, also prevents BSCB breakdown after neural injury and actively inhibits TNF-α-induced endothelial permeability in vitro, which is not evident the case for human thrombin. Salmon thrombin's production of APC faster than human thrombin is confirmed using a fluorogenic assay and APC is shown to inhibit BSCB breakdown and pain-related behaviors similar to salmon thrombin. Together, these studies highlight the impact of BSCB on pain and establish salmon thrombin as an effective blocker of BSCB, and resulting nociception, through its preferential affinity for protein C.