Serum Interleukin (IL)-23 and IL-17 Profile in Inflammatory Bowel Disease (IBD) Patients Could Differentiate between Severe and Non-Severe Disease

Exploration of the core pathway of inflammatory bowel disease complicated with metabolic fatty liver and two-sample Mendelian randomization study of the causal relationships behind the disease

Background

Inflammatory bowel disease (IBD) is often associated with complex extraintestinal manifestations. The incidence of nonalcoholic fatty liver disease (NAFLD) in IBD populations is increasing yearly. However, the mechanism of interaction between NAFLD and IBD is not clear. Consequently, this study aimed to explore the common genetic characteristics of IBD and NAFLD and identify potential therapeutic targets.

Materials and methods

Gene chip datasets for IBD and NAFLD were obtained from the Gene Expression Omnibus (GEO) database. Weighted gene co-expression network analysis (WGCNA) was performed to identify modules in those datasets related to IBD and NAFLD. ClueGO was used for biological analysis of the shared genes between IBD and NAFLD. Based on the Human MicroRNA Disease Database (HMDD), microRNAs (miRNAs) common to NAFLD and IBD were obtained. Potential target genes for the miRNAs were predicted using the miRTarbase, miRDB, and TargetScan databases. Two-sample Mendelian randomization (MR) and two-way MR were used to explore the causal relationship between Interleukin-17 (IL-17) and the risk of IBD and NAFLD using data from GWAS retrieved from an open database.

Results

Through WGCNA, gene modules of interest were identified. GO enrichment analysis using ClueGO suggested that the abnormal secretion of chemokines may be a common pathophysiological feature of IBD and NAFLD, and that the IL-17-related pathway may be a common key pathway for the pathological changes that occur in IBD and NAFLD. The core differentially expressed genes (DEGs) in IBD and NAFLD were identified and included COL1A1, LUM, CCL22, CCL2, THBS2, COL1A2, MMP9, and CXCL8. Another cohort was used for validation. Finally, analysis of the miRNAs identified potential therapeutic targets. The MR results suggested that although there was no causal relationship between IBD and NAFLD, there were causal relationships between IL-17 and IBD and NAFLD.

Conclusion

We established a comorbid model to explain the potential mechanism of IBD with NAFLD and identified the chemokine-related pathway mediated by cytokine IL-17 as the core pathway in IBD with NAFLD, in which miRNA also plays a role and thus provides potential therapeutic targets.

Level of interleukin 17 in inflammatory bowel disease and its relation with disease activity

BACKGROUND

Inflammatory bowel disease (IBD) is a chronic relapsing inflammatory disorder of the gastrointestinal tract (GIT).It results in progressive intestinal epithelium structural and functional damage that necessitates lifetime medication.Thereis imbalance in the production of T helper 1 (Th1), Th2 and Th17 cytokines. This plays a crucial role in the chronic inflammatory process and the defective immune response to pathogenic agents; thus promoting the recurrence of the disease.Our aim of this study was to detect serum IL-17 levels in IBD patients and its relation with disease activity.

METHODS

This was a single center case control study, conducted at hepatology and gastroenterology unit, Mansoura specialized Medical Hospital, Egypt.Patients who were included were aged 18-65 years, diagnosed either Ulcerative Colitis (UC)or Crohn's Disease (CD) based on previous colonoscopy.IBD activity was measured for UC using the MAYO score and CD using the CD activity index (CDAI). Fifty five patients were UC, 24 patients were CD, 21 patients were control.Patients who were excluded were under 15 years old, with history of GIT malignancy, or any serious comorbidities. Study protocol was approved by Institution Research Board (IRB) of Mansoura Medical College.All patients were subjected to full history taking, routine physical examination, colonoscopy and laboratory investigations including serum IL-17 levels by ELISA besides CBC, CRP, ESR and fecal calprotectin.

RESULTS

Serum IL-17 level was increased significantly among UC; median (min-max) = 72(21-502)pg/ml, in CD 54.5(25-260) versus control 19 (14-35), P < 0.001.However, it was not correlated to the disease activity either Mayo score of UC or CDAI of CD.There was significant correlation to the extent of inflammation in UC affecting the colon (either proctosigmoiditis, left sided colitis or pan colitis), also to the type of CD (either inflammatory, stricturing or fistulizing) by P < 0.05.It was not correlated significantly with any of the IBD activity markers (CRP, ESR, or fecal calprotectin).Yet there was negative significant correlation with Hb level (r =-0.28, p = 0.005).There was not significant association between median serum level of IL-17 & duration of disease (P = 0.6).However, median IL-17 was higher among hospitalized cases than non-hospitalized (73 & 55, pg/ml respectively; p < 0.002). AUC was significantly differentiating between IBD and control group = 0.993 with the best-detected cut off point from curve 32 pg/ml yielding sensitivity of 97.5% and specificity of 95.2%.

CONCLUSION

Serum IL-17 increases in colonic inflammation significantly more than in control group, however its increase is not correlated to IBD activity.

Circulating levels of cytokines and risk of inflammatory bowel disease: evidence from genetic data

Background

Prior epidemiological studies have established a correlation between inflammatory cytokines and inflammatory bowel disease (IBD). However, the nature of this relationship remains uncertain. Mendelian randomization (MR) study has the advantages of avoiding confounding and reverse causality compared with traditional observational research.

Objective

We aimed to evaluate whether genetically determined circulating levels of cytokines are associated with the risk of IBD by using the MR approach.

Materials and methods

We selected genetic variants associated with circulating levels of 28 cytokines at the genome-wide significance level from a genome-wide association study (GWAS) including 8,293 individuals. Summary-level data for IBD (including Crohn's disease and ulcerative colitis) were obtained from the International Inflammatory Bowel Disease Genetics Consortium and UK Biobank. We performed the primary analysis using the inverse-variance weighted method, as well as sensitivity analyses to test the stability of our results. We subsequently replicated the results of IBD in the UK Biobank dataset. A reverse MR analysis was also conducted to evaluate the possibility of reverse causation.

Results

Genetically predicted elevated levels of interleukin-17 (IL-17) and monokine induced by interferon-gamma (MIG) were associated with an increased risk of IBD[odds ratio (OR): 1.52, 95% confidence interval (CI):1.10-2.08, P =0.010 for IL-17 and OR: 1.58, 95% CI: 1.24-2.00, P = 1.60×10-4 for MIG]. Moreover, we observed suggestive associations between β-NGF and MIP-1β with the risk of Crohn's disease (OR: 0.71, 95% CI: 0.52-0.98, P = 0.039) and ulcerative colitis (OR: 1.08, 95% CI: 1.01-1.15, P= 0.019). In the reverse MR study, there was no evidence of causal effects of IBD and these cytokines.

Conclusion

Our study suggests the potential causal associations of IL-17 and MIG with IBD. Further studies are needed to determine whether IL-17 and MIG or their downstream effectors could be useful in the management of IBD.

A Narrative Review of Cytokine Networks: Pathophysiological and Therapeutic Implications for Inflammatory Bowel Disease Pathogenesis

Inflammatory bowel disease (IBD) is a lifelong inflammatory immune mediated disorder, encompassing Crohn's disease (CD) and ulcerative colitis (UC); however, the cause and specific pathogenesis of IBD is yet incompletely understood. Multiple cytokines produced by different immune cell types results in complex functional networks that constitute a highly regulated messaging network of signaling pathways. Applying biological mechanisms underlying IBD at the single omic level, technologies and genetic engineering enable the quantification of the pattern of released cytokines and new insights into the cytokine landscape of IBD. We focus on the existing literature dealing with the biology of pro- or anti-inflammatory cytokines and interactions that facilitate cell-based modulation of the immune system for IBD inflammation. We summarize the main roles of substantial cytokines in IBD related to homeostatic tissue functions and the remodeling of cytokine networks in IBD, which may be specifically valuable for successful cytokine-targeted therapies via marketed products. Cytokines and their receptors are validated targets for multiple therapeutic areas, we review the current strategies for therapeutic intervention and developing cytokine-targeted therapies. New biologics have shown efficacy in the last few decades for the management of IBD; unfortunately, many patients are nonresponsive or develop therapy resistance over time, creating a need for novel therapeutics. Thus, the treatment options for IBD beyond the immune-modifying anti-TNF agents or combination therapies are expanding rapidly. Further studies are needed to fully understand the immune response, networks of cytokines, and the direct pathogenetic relevance regarding individually tailored, safe and efficient targeted-biotherapeutics.

Detection of IL12/23p40 via PET Visualizes Inflammatory Bowel Disease

Inflammatory bowel disease (IBD), which includes both Crohn disease and ulcerative colitis, is a relapsing inflammatory disease of the gastrointestinal tract. Long-term chronic inflammatory conditions elevate the patient's risk of colorectal cancer (CRC). Currently, diagnosis requires endoscopy with biopsy. This procedure is invasive and requires a bowel-preparatory regimen, adding to patient burden. Interleukin 12 (IL12) and interleukin 23 (IL23) play key roles in inflammation, especially in the pathogenesis of IBD, and are established therapeutic targets. We propose that imaging of IL12/23 and its p40 subunit in IBD via immuno-PET potentially provides a new noninvasive diagnostic approach. Methods: Our aim was to investigate the potential of immuno-PET to image inflammation in a chemically induced mouse model of colitis using dextran sodium sulfate by targeting IL12/23p40 with a 89Zr-radiolabeled anti-IL12/23p40 antibody. Results: High uptake of the IL12/23p40 immuno-PET agent was exhibited by dextran sodium sulfate-administered mice, and this uptake correlated with increased IL12/23p40 present in the sera. Competitive binding studies confirmed the specificity of the radiotracer for IL12/23p40 in the gastrointestinal tract. Conclusion: These promising results demonstrate the utility of this radiotracer as an imaging biomarker of IBD. Moreover, IL12/23p40 immuno-PET can potentially guide treatment decisions for IBD management.

The Role of IL-23 in the Pathogenesis and Therapy of Inflammatory Bowel Disease

Interleukin-23 (IL-23) is a proinflammatory cytokine produced mainly by macrophages and antigen-presenting cells (APCs) after antigenic stimulation. IL-23 plays a significant role as a mediator of tissue damage. Indeed, the irregularities in IL-23 and its receptor signaling have been implicated in inflammatory bowel disease. IL-23 interacts with both the innate and adaptive immune systems, and IL-23/Th17 appears to be involved in the development of chronic intestinal inflammation. The IL-23/Th17 axis may be a critical driver of this chronic inflammation. This review summarizes the main aspects of IL-23's biological function, cytokines that control cytokine production, effectors of the IL-23 response, and the molecular mechanisms associated with IBD pathogenesis. Although IL-23 modulates and impacts the development, course, and recurrence of the inflammatory response, the etiology and pathophysiology of IBD are not completely understood, but mechanism research shows huge potential for clinical applications as therapeutic targets in IBD treatment.

New-Onset Crohn's Disease following Initiation of Secukinumab: A Case Report and Review of the Role of IL-17 in the Pathogenesis of Crohn's Disease

Patients with autoimmune conditions show a high expression of proinflammatory cytokines including interleukin (IL)-17. While IL-17 inhibitors have demonstrated efficacy in managing autoimmune disorders, rare instances of de novo or exacerbated inflammatory bowel disease (IBD) have been reported. The factors that affect the onset and severity remain unclear. Here, we present a case of a 38-year-old female who developed manifestations of Crohn's disease within 1 month of initiating secukinumab treatment for psoriatic arthritis, in addition to a review of the role of IL-17 in the pathophysiology of Crohn's disease.

Deciphering the pharmacological mechanisms of Fraxini Cortex for ulcerative colitis treatment based on network pharmacology and in vivo studies

BACKGROUND

Ulcerative colitis (UC) is a common type of inflammatory bowel disease. Due to the elusive pathogenesis, safe and effective treatment strategies are still lacking. Fraxini Cortex (FC) has been widely used as a medicinal herb to treat some diseases. However, the pharmacological mechanisms of FC for UC treatment are still unclear.

METHODS

An integrated platform combining network pharmacology and experimental studies was introduced to decipher the mechanism of FC against UC. The active compounds, therapeutic targets, and the molecular mechanism of action were acquired by network pharmacology, and the interaction between the compounds and target proteins were verified by molecular docking. Dextran sulfate sodium (DSS)-induced colitis model was employed to assess the therapeutic effect of FC on UC, and validate the molecular mechanisms of action predicted by network pharmacology.

RESULTS

A total of 20 bioactive compounds were retrieved, and 115 targets were predicted by using the online databases. Ursolic acid, fraxetin, beta-sitosterol, and esculetin were identified as the main active compounds of FC against UC. PPI network analysis identified 28 FC-UC hub genes that were mainly enriched in the IL-17 signaling pathway, the TNF signaling pathway, and pathways in cancer. Molecular docking confirmed that the active compounds had high binding affinities to the predicted target proteins. GEO dataset analysis showed that these target genes were highly expressed in the UC clinical samples compared with that in the healthy controls. Experimental studies showed that FC alleviated DSS-induced colitis symptoms, reduced inflammatory cytokines release, and suppressed the expression levels of IL1β, COX2, MMP3, IL-17 and RORγt in colon tissues.

CONCLUSION

FC exhibits anti-UC properties through regulating multi-targets and multi-pathways with multi-components. In vivo results demonstrated that FC alleviated DSS-induced colitis.

Traditional Chinese Medicine Regulates Th17/Treg Balance in Treating Inflammatory Bowel Disease

Inflammatory bowel disease (IBD), also known as chronic nonspecific inflammatory disease of the colon and rectum, is primarily characterized by mucopurulent bloody stools, diarrhea, abdominal pain, and tenesmus. Its cause is uncertain. IBD patients frequently experience a high rate of recurrence, a protracted treatment course, and a high risk of carcinogenesis. Additionally, the difficulty of treatment is significantly increased by these illness characteristics. Currently, the normal treatment for this illness can lessen symptoms to some amount and even meet clinical treatment requirements, but due to serious side effects, unfavorable reactions, and high costs, we need to develop better complementary and alternative medicines. A number of studies have found that the imbalance of T helper cell 17 (Th17)/regulatory T cells (Treg) contributes significantly to the occurrence and progression of IBD and that Th17/Treg balance restoration is frequently useful in the management of IBD. As a result, regulating the Th17/Treg balance has also emerged as a novel approach to treating IBD. Traditional Chinese medicine (TCM) has gained popularity in recent years due to its advantages of low side effects, a variety of targets, and multiple regulatory mechanisms. A number of studies have shown that TCM can successfully intervene in the Th17/Treg imbalance and restore it, and research on the prevention and treatment of IBD by TCM by restoring Th17/Treg has also shown promising results. The characteristics of the Th17/Treg balance and its role in the pathogenesis of IBD, as well as the role of TCM in regulating the Th17/Treg imbalance, are analyzed. The research results are expected to provide a theoretical basis for the clinical treatment and pathology mechanism research of IBD.

Inflammatory Bowel Disease: A Review of Pre-Clinical Murine Models of Human Disease

Crohn’s disease (CD) and ulcerative colitis (UC) are both highly inflammatory diseases of the gastrointestinal tract, collectively known as inflammatory bowel disease (IBD). Although the cause of IBD is still unclear, several experimental IBD murine models have enabled researchers to make great inroads into understanding human IBD pathology. Here, we discuss the current pre-clinical experimental murine models for human IBD, including the chemical-induced trinitrobenzene sulfonic acid (TNBS) model, oxazolone and dextran sulphate sodium (DSS) models, the gene-deficient I-kappa-B kinase gamma (Iκκ-γ) and interleukin(IL)-10 models, and the CD4⁺ T-cell transfer model. We offer a comprehensive review of how these models have been used to dissect the etiopathogenesis of disease, alongside their limitations. Furthermore, the way in which this knowledge has led to the translation of experimental findings into novel clinical therapeutics is also discussed.

The Treatment with Interleukin 17 Inhibitors and Immune-Mediated Inflammatory Diseases

IL-17 inhibitors (IL-17i) are medicines used to treat dermatological and rheumatic diseases They belong to a class of medicines called biological disease-modifying anti-rheumatic drugs (bDMARDs). This class of drugs has had a major impact on the therapy of autoimmune diseases, being much safer and more effective than treatment with small molecules. At the same time, they have highly beneficial effects on skin and joint changes, and their efficacy has been extensively monitored and demonstrated in numerous clinical trials. More and more such drugs are still being discovered today to ensure the best possible treatment of these patients, but more frequently and relatively constantly three agents are used. Two of them (Secukinumab and Ixekizumab) inhibit IL-17A directly, and the third, Brodamulab, inhibits the IL-17A receptor. Although they are extremely effective in the treatment of these diseases, sometimes their administration has been associated with paradoxical effects, i.e., there is an exacerbation of the inflammatory process. Tough, clinical trials of IL-17i have described cases of exacerbation or even onset of inflammatory bowel disease (IBD), such as Crohn’s disease and ulcerative colitis, after administration of these drugs in patients previously diagnosed with psoriasis (PS), psoriatic arthritis (PsA), or ankylosing spondylitis (AS). The pathophysiological mechanism of action is not well understood at present. One explanation would be that this hyperreactive inflammatory process would be triggered by Interferon 1 derived from dendritic plasma cells. Even though there are many reports in the recent literature about the role of IL17i in the onset of IBD, conclusions of studies do not converge. Some of them show an increased incidence of IBD in patients treated with IL17i, while some others affirm their safety of them. In the near future we will surely have more data emerging from ongoing meta-analyses regarding safety of use IL17i in patients who are at risk of developing IBD. Clinical and paraclinical evaluation (inflammatory intestinal markers) are carefully advised before recommending treatment with IL-17i and after initiation of treatment, and prospective surveillance by clinical and biomarkers of patients treated with IL-17i is absolutely essential to capture the onset of IBD.