Emerging Biomarkers for the Diagnosis and Monitoring of Inflammatory Bowel Diseases

The miRNA Landscape in Crohn's disease: Implications for novel therapeutic approaches and interactions with Existing therapies

MicroRNAs (miRNAs), which are non-coding RNAs consisting of 18-24 nucleotides, play a crucial role in the regulatory pathways of inflammatory diseases. Several recent investigations have examined the potential role of miRNAs in forming Crohn's disease (CD). It has been suggested that miRNAs serve as diagnostics for both fibrosis and inflammation in CD due to their involvement in the mechanisms of CD aggravation and fibrogenesis. More information on CD pathophysiology could be obtained by identifying the miRNAs concerned with CD and their target genes. These findings have prompted several in vitro and in vivo investigations into the putative function of miRNAs in CD treatment. Although there are still many unanswered questions, the growing body of evidence has brought miRNA-based therapy one step closer to clinical practice. This extensive narrative study offers a concise summary of the most current advancements in CD. We go over what is known about the diagnostic and therapeutic benefits of miRNA mimicry and inhibition so far, and we see what additional miRNA family targets could be useful for treating CD-related inflammation and fibrosis.

Development and validation of diagnosis model for inflammatory bowel diseases based on a serologic biomarker panel: A decision tree model study

BACKGROUND AND STUDY AIMS

Currently, an increasing amount of experimental data is available on newly discovered biomarkers in inflammatory bowel diseases (IBD), but the role of these biomarkers is often questionable due to their limited sensitivity. Therefore, this study aimed to build a diagnostic tool incorporating a panel of serum biomarkers into a computational algorithm to identify patients with IBD and differentiate those with Crohn's disease (CD) from those with ulcerative colitis (UC).

PATIENTS AND METHODS

We studied sera from 192 CD patients, 118 UC patients, 60 non-IBD controls and 60 healthy controls. Indirect immunofluorescence (IIF) assays were utilized to determine several serum biomarkers previously associated with IBD, and the decision tree algorithm was used to construct the diagnosis model. Performances of models were evaluated by prediction accuracy, precision, AUC and Matthews's correlation coefficient (MCC). The "Inflammatory Bowel Disease Multi-omics Database (IBDMDB)" cohorts were used to validate the model as external validation set.

RESULTS

The prediction rates were determined and compared for decision tree models after each data was developed using C5.0, C&RT, QUEST and CHAID. The C5.0 and CHAID algorithms, which ranked top for the prediction rate in the IBD vs. non-IBD model and the CD vs. UC model, respectively, were utilized for final pattern analysis. The final decision tree model achieved higher classification accuracy than the approach based on conservative marker combinations (sensitivity 75.0% vs. 79.5%, specificity 93.8% vs. 78.3% for differentiating IBD from non-IBD; and sensitivity 84.3% vs. 73.4%, specificity 92.5% vs. 54.9% for differentiating CD from UC, respectively). The model prediction consistency was 93% (28/30) in the external validation set.

CONCLUSION

The decision-tree-based approach used in this study, based on serum biomarkers, has shown to be a valid and useful approach to identifying IBD and differentiating CD from UC.

Anti-TNFα in inflammatory bowel disease: from originators to biosimilars

The introduction of anti-tumor necrosis factor α (TNFα) biologics significantly innovated inflammatory bowel disease (IBD) treatment and increased medical costs. The recent expiration of patents of some anti-TNFα biologics (such as infliximab and adalimumab) facilitated the development of biosimilars. Comparable pharmacokinetic, efficacy, safety, and immunogenicity profiles between anti-TNFα originators and biosimilars were demonstrated in different studies. Anti-TNFα biosimilars hold promise for reducing the high cost of biologics and increasing patient access to biologics. In this review, we outline the current data on the use of anti-TNFα originators and biosimilars in patients with IBD, with a focus on the efficacy, safety, and immunogenicity profiles of infliximab and adalimumab biosimilars. The potential benefits, challenges, and future directions of anti-TNFα biosimilars are also discussed in the review.

Effect of Stool Sampling on a Routine Clinical Method for the Quantification of Six Short Chain Fatty Acids in Stool Using Gas Chromatography-Mass Spectrometry

Short chain fatty acids (SCFAs) are primarily produced in the caecum and proximal colon via the bacterial fermentation of undigested carbohydrates that have avoided digestion in the small intestine. Increasing evidence supports the critical role that SCFAs play in health and homeostasis. Microbial SCFAs, namely butyric acid, serve as a principal energy source for colonocytes, and their production is essential for gut integrity. A direct link between SCFAs and some human pathological conditions, such as inflammatory bowel disease, irritable bowel syndrome, diarrhea, and cancer, has been proposed. The direct measurement of SCFAs in feces provides a non-invasive approach to demonstrating connections between SCFAs, microbiota, and metabolic diseases to estimate their potential applicability as meaningful biomarkers of intestinal health. This study aimed to adapt a robust analytical method (liquid-liquid extraction, followed by isobutyl chloroformate derivatization and GC-MS analysis), with comparable performances to methods from the literature, and to use this tool to tackle the question of pre-analytical conditions, namely stool processing. We focused on the methodology of managing stool samples before the analysis (fresh stool or dilution in either ethanol/methanol, lyophilized stool, or RNAlater®), as this is a significant issue to consider for standardizing results between clinical laboratories. The objective was to standardize methods for future applications as diagnostic tools. In this paper, we propose a validated GC-MS method for SCFA quantification in stool samples, including pre- and post-analytical comparison studies that could be easily used for clinical laboratory purposes. Our results show that using lyophilization as a stool-processing method would be the best method to achieve this goal.

Clinical significance of the C-reactive protein-to-bilirubin ratio in patients with ulcerative colitis

Background

Ulcerative colitis (UC) is a chronic relapsing remitting disease of the colon. Appropriate monitoring of the disease status is necessary for patients to adopt optimal therapy and obtain a better prognosis. Finding an ideal non-invasive biomarker, which is suitable for long-term monitoring in clinical settings will bring a significant benefit to the individualized management of patients with UC. The aim of this study is to determine the clinical significance of a novel optimizing serological biomarker by integrating C-reactive protein (CRP) and bilirubin levels in monitoring disease activity.

Methods

A total of 182 patients with UC were retrospectively enrolled. Clinical characteristics and laboratory parameters of the subjects were retrieved from the electronic medical record database of our hospital. The CRP-to-bilirubin ratio (CBR) was computed for clinical activity of UC defined by the partial Mayo score and endoscopic activity by the Mayo endoscopic score (MES).

Results

CBR was significantly elevated in patients with UC than that in healthy controls. Patients with clinically or endoscopically active UC showed evidently higher CBR levels compared to those with inactive disease, even in a subset of patients with normal CRP levels. Receiver operating characteristic (ROC) analysis showed that the area under the curve (AUC) of CBR was higher than that of CRP or bilirubin alone for determining clinical remission and endoscopic mucosal improvement. Furthermore, CBR levels were significantly decreased when patients achieved mucosal improvement compared with when they had active endoscopic inflammation.

Conclusion

CBR could be useful to reflect disease activity in patients with UC.

Clinical Utility of the Neutrophil-to-Bilirubin Ratio in the Detection of Disease Activity in Ulcerative Colitis

Background

Ulcerative colitis (UC) is a chronic relapsing remitting form of inflammatory bowel disease (IBD). Current disease monitoring includes evaluation of symptoms, fecal calprotectin, and colonoscopy. Due to limited availability of the latter two modalities in China, we sought a readily available, inexpensive, disease monitoring laboratory assessment. We recently identified a novel serological index (the neutrophil-to-bilirubin ratio, NBR) for monitoring disease activity in Crohn's disease. However, the clinical significance has not been evaluated in UC. Here, we aimed to verify the hypothesis that NBR might be useful in monitoring clinical and endoscopic activity in patients with UC.

Methods

To test our hypothesis, we conducted a single-center, retrospective study including a total of 188 patients with UC and 145 non-IBD controls. NBR was calculated to determine its practical value in monitoring disease activity (including clinical and endoscopic activity). Disease activity of UC was determined by the partial Mayo score and the Mayo endoscopic score (MES) system.

Results

NBR was significantly higher in patients with UC than that in controls (12.10, IQR: 9.85-16.69 versus 5.06, IQR: 3.94-6.55; p < 0.001) and showed positive correlations with clinical and endoscopic disease activity in UC. Additionally, NBR was significantly lower in patients with endoscopic mucosal healing (MH) than that in those without endoscopic MH (8.81, IQR: 6.67-11.67 versus 13.51, IQR: 11.04-18.71; p < 0.001). Serial evaluation of NBR in a subset of patients demonstrated that NBR was significantly decreased during the MH stage compared with that during the endoscopically active stage.

Conclusion

Our study suggests that NBR may be a promising candidate for assessing disease activity in UC, with potential for widespread clinical use and significant clinical implications.

Proteomic Analysis Identifies Three Reliable Biomarkers of Intestinal Inflammation in the Stools of Patients With Inflammatory Bowel Disease

BACKGROUND

Faecal biomarkers have emerged as important tools in managing of inflammatory bowel disease [IBD], which includes Crohn's disease [CD] and ulcerative colitis [UC].

AIM

To identify new biomarkers of gut inflammation in the stools of IBD patients using a proteomic approach.

METHODS

Proteomic analysis of stools was performed in patients with both active CD and CD in remission and in controls by 2-DIGE and MALDI-TOF/TOF MS. An ELISA was used to confirm results in a second cohort of IBD patients and controls.

RESULTS

2-DIGE analysis detected 70 spots in the stools of patients with active CD or patients in remission CD and in controls. MALDI-TOF/TOF MS analysis identified 21 proteins with Chymotrypsin C, Gelsolin and Rho GDP-dissociation inhibitor 2 [RhoGDI2] best correlating with the levels of intestinal inflammation. Results were confirmed in a second cohort of IBD patients and controls [57 CD, 60 UC, 31 controls]. The identified faecal markers significantly correlated with the severity of intestinal inflammation in IBD patients [SES-CD in CD, Mayo endoscopic subscore in UC] [CD; Chymotrypsin-C: r = 0.64, p < 0.001; Gelsolin: r = 0.82, p < 0.001; RhoGDI2: r = 0.64, p < 0.001; UC; Chymotrypsin-C: r = 0.76, p < 0.001; Gelsolin: r = 0.75, p < 0.001; RhoGDI2: r = 0.63, p < 0.001]. Moreover, ROC analysis showed that Gelsolin [p < 0.0002] and RhoGDI2 [p < 0.0001] in CD, and RhoGDI2 [p = 0.0004] in UC, have higher sensitivity and specificity than faecal calprotectin in discriminating between patients and controls.

CONCLUSIONS

We show for the first time that 2-DIGE is a reliable method to detect proteins in human stools. Three novel faecal biomarkers of gut inflammation have been identified that display good specificity and sensitivity for identifying IBD and significantly correlate with IBD severity.

A Novel Neutrophil-Based Biomarker to Monitor Disease Activity and Predict Response to Infliximab Therapy in Patients With Ulcerative Colitis

Background

Ulcerative colitis (UC) is characterized by refractory and recurrent mucosal inflammation, leading to a substantial healthcare burden. Diagnostic biomarkers predicting disease activity and treatment response remain elusive. To evaluate the application value of a novel neutrophil-based index (the neutrophil-to-albumin ratio, NAR) as a novel diagnostic biomarker in patients with UC and a predictive marker for disease activity and response to infliximab (IFX) therapy.

Methods

Clinical characteristics and laboratory parameters of enrolled subjects (patients with UC and healthy controls) were retrieved from the electronic medical record database of our hospital. Serum cytokine and fecal calprotectin levels were measured by enzyme-linked immunosorbent assay (ELISA). Mucosal expression levels of inflammatory agents were measured by quantitative RT-PCR (qRT-PCR).

Results

We found that NAR, which had not yet been explored in UC, was significantly increased in patients with UC (n = 146) compared to that in controls (n = 133) (1.95 ± 0.41 vs. 1.41 ± 0.23, p < 0.0001). NAR showed a positive association with the disease activity and inflammatory load in patients with UC. Pre-treatment NAR was significantly lower in IFX responders than that in non-responders (2.18 ± 0.29 vs. 2.44 ± 0.21, p = 0.0118), showing a significant ability to discriminate initial responders from primary non-responders to IFX induction therapy (AUC = 0.7866, p = 0.0076). Moreover, pre-treatment NAR predicted postinduction serum IFX trough level.

Conclusion

Our study provides evidences to utilize NAR in the diagnosis, activity monitoring, and IFX response prediction in patients with UC.

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

Interleukin (IL)-17 and IL-23 are crucial for mediating gut mucosal inflammation in inflammatory bowel disease (IBD), which has led to new therapeutic strategies. We assessed the relevancy of IL-17 and IL-23 serum levels as potential biomarkers towards severe IBD discrimination and disease-related complications. Sixty-two patients diagnosed with Crohn's disease (CD) and ulcerative colitis (UC) were included. Serum IL-17 and IL-23 were measured by sandwich enzyme-linked immunosorbent assays (ELISA). IL-23 and fecal calprotectin (FCal) were significantly higher in severe CD (p < 0.001) and UC (p < 0.001 and p = 0.001, respectively), compared to mild or moderate. Elevated C-reactive protein (CRP) was correlated with severe disease only in CD (p = 0.008), whereas for UC, disease severity was associated with increased IL-17 values (p < 0.001). Diagnostic role of IL-23 was superior to FCal in discriminating between severe and mild to moderate CD (p < 0.001). IL-23 levels were also significantly higher in CD patients with intestinal complications (p = 0.04). Both IL-17 and IL-23 correlate with IBD severity, and IL-23 might be a promising novel biomarker for severe CD. Identifying the dominant IL pathway involved in IBD severity could serve as guidance for clinical decision-making on biologic therapy.

Inflammatory Bowel Disease and Neutrophil-Lymphocyte Ratio: A Systematic Scoping Review

Neutrophil–lymphocyte ratio (NLR) is a biomarker of the systemic inflammatory response. The objective of this systematic scoping review was to examine the literature on NLR and inflammatory bowel disease (IBD). PubMed, Embase, Cochrane CENTRAL, CINAHL, ClinicalTrials.gov, Cochrane Specialized Register, DOAJ, PDQT, Biosis Citation Index, Scopus, and Web of Science were systematically searched. A total of 2621 citations yielding 62 primary studies were synthesized under four categories: distinguishing patients with IBD from controls, disease activity differentiation, clinical outcome prediction, and association of NLR with other IBD biomarkers. Thirty-eight studies employed receiver operating characteristic (ROC) curve analysis to generate optimal NLR cutpoints for applications including disease activity differentiation and prediction of response to treatment. Among the most promising findings, NLR may have utility for clinical and endoscopic disease activity differentiation and prediction of loss of response to infliximab (IFX). Overall findings suggest NLR may be a promising IBD biomarker. Assessment of NLR is non-invasive, low cost, and widely accessible given NLR is easily calculated from blood count data routinely and serially monitored in patients with IBD. Further research is justified to elucidate how evaluation of NLR in research and clinical practice would directly impact the quality and cost of care for patients living with IBD.

Long-term effects of increasing omega-3, omega-6 and total polyunsaturated fats on inflammatory bowel disease and markers of inflammation: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND AND AIM

Effects of long-chain omega-3 (LCn3) and omega-6 fatty acids on prevention and treatment of inflammatory bowel diseases (IBD, including Crohn's Disease, CD and ulcerative colitis, UC), and inflammation are unclear. We systematically reviewed long-term effects of omega-3, omega-6 and total polyunsaturated fats (PUFA) on IBD diagnosis, relapse, severity, pharmacotherapy, quality of life and key inflammatory markers.

METHODS

We searched Medline, Embase, Cochrane CENTRAL, and trials registries, including RCTs in adults with or without IBD comparing higher with lower omega-3, omega-6 and/or total PUFA intake for ≥ 24 weeks that assessed IBD-specific outcomes or inflammatory biomarkers.

RESULTS

We included 83 RCTs (41,751 participants), of which 13 recruited participants with IBD. Increasing LCn3 may reduce risk of IBD relapse (RR 0.85, 95% CI 0.72-1.01) and IBD worsening (RR 0.85, 95% CI 0.71-1.03), and reduce erythrocyte sedimentation rate (ESR, SMD - 0.23, 95% CI - 0.44 to - 0.01), but may increase IBD diagnosis risk (RR 1.10, 95% CI 0.63-1.92), and faecal calprotectin, a specific inflammatory marker for IBD (MD 16.1 μg/g, 95% CI - 37.6 to 69.8, all low-quality evidence). Outcomes for alpha-linolenic acid, omega-6 and total PUFA were sparse, but suggested little or no effect where data were available.

CONCLUSION

This is the most comprehensive meta-analysis of RCTs investigating long-term effects of omega-3, omega-6 and total PUFA on IBD and inflammatory markers. Our findings suggest that supplementation with PUFAs has little or no effect on prevention or treatment of IBD and provides little support for modification of long-term inflammatory status.

miRNA-Based Potential Biomarkers and New Molecular Insights in Ulcerative Colitis

Ulcerative colitis (UC) is a chronic non-specific inflammatory bowel disease, which usually manifests as abdominal pain, diarrhea and hematochezia. The disease often recurs and is difficult to cure. At present, the pathogenesis is not clear, but it is believed that the disease is caused by a complex interaction among immunity, heredity, environment and intestinal microflora disorders. MicroRNA (miRNA) is endogenous single-stranded non-coding RNA of 17–25 nucleotides (nts). They target the 3'Untranslated Region of a target gene and inhibit or degrade the target gene according to the extent of complementary bases. As important gene expression regulators, miRNAs are involved in regulating the expression of most human genes, and play an important role in the pathogenesis of many autoimmune diseases including UC. Studies in recent years have illustrated that abnormal expression of miRNA occurs very early in disease pathogenesis. Moreover, this abnormal expression is highly related to disease activity of UC and colitis-associated cancer, and involves virtually all key UC-related mechanisms, such as immunity and intestinal microbiota dysregulation. Recently, it was discovered that miRNA is highly stable outside the cell in the form of microvesicles, exosomes or apoptotic vesicles, which raises the possibility that miRNA may serve as a novel diagnostic marker for UC. In this review, we summarize the biosynthetic pathway and the function of miRNA, and summarize the usefulness of miRNA for diagnosis, monitoring and prognosis of UC. Then, we described four types of miRNAs involved in regulating the mechanisms of UC occurrence and development: 1) miRNAs are involved in regulating immune cells; 2) affect the intestinal epithelial cells barrier; 3) regulate the homeostasis between gut microbiota and the host; and 4) participate in the formation of tumor in UC. Altogether, we aim to emphasize the close relationship between miRNA and UC as well as to propose that the field has value for developing potential biomarkers as well as therapeutic targets for UC.

Raman Analysis Reveals Biochemical Differences in Plasma of Crohn's Disease Patients

BACKGROUNDS AND AIMS

There is no accurate and reliable circulating biomarker to diagnose Crohn's disease [CD]. Raman spectroscopy is a relatively new approach that provides information on the biochemical composition of samples in minutes and virtually without any sample preparation. We aimed to test the use of Raman spectroscopy analysis of plasma samples as a potential diagnostic tool for CD.

METHODS

We analysed by Raman spectroscopy dry plasma samples obtained from 77 CD patients [CD] and 45 healthy controls [HC]. In the dataset obtained, we analysed spectra differences between CD and HC, as well as among CD patients with different disease behaviours. We also developed a method, based on principal component analysis followed by a linear discrimination analysis [PCA-LDA], for the automatic classification of individuals based on plasma spectra analysis.

RESULTS

Compared with HC, the CD spectra were characterised by less intense peaks corresponding to carotenoids [p <10-4] and by more intense peaks corresponding to proteins with β-sheet secondary structure [p <10-4]. Differences were also found on Raman peaks relative to lipids [p = 0.0007] and aromatic amino acids [p <10-4]. The predictive model we developed was able to classify CD and HC subjects with 83.6% accuracy [sensitivity 80.0% and specificity 85.7%] and F1-score of 86.8%.

CONCLUSIONS

Our results indicate that Raman spectroscopy of blood plasma can identify metabolic variations associated with CD and it could be a rapid pre-screening tool to use before further specific evaluation.

Lyophilized fecal short-chain fatty acid and electrolyte determination by capillary electrophoresis with indirect UV detection for assessment of pediatric inflammatory bowel disease

Short-chain fatty acids (SCFAs) and electrolytes are major constituents of human feces involved in maintaining gastrointestinal homeostasis that underlie complex diet, host and microbiome interactions. Reliable quantification of SCFAs and electrolytes is challenging given the heterogeneity of stool specimens from pediatric patients with diarrhea-predominate inflammatory bowel disease (IBD). Herein, we introduce two validated methods for determination of 3 SCFAs and 5 electrolytes consistently quantified from fecal extracts when using capillary electrophoresis with indirect UV detection (CE-iUV), where concentrations are normalized to total dried weight (mmol/kg d.w.). Lyophilization facilitates sample handling and extraction of heterogeneous stool specimens (∼ 15 mg) from a cohort of children with Crohn's disease (CD, n = 12) and ulcerative colitis (UC, n = 10) treated with exclusive enteral nutrition (EEN) or corticosteroid (CS) therapy to induce remission, respectively. Good technical precision (mean CV = 13 %, n = 14) and accuracy (recovery from 84 to 116%) is demonstrated for SCFAs and electrolytes from freeze dried stool extracts using a modified Bligh-Dyer protocol with low micromolar detection limits (∼ 2-15 μM). Fecal butyrate is 2.6-fold higher in CD as compared to UC patients (effect size = 1.51; p = 0.00291), and there is a strong co-linearity between fecal butyrate and acetate (r = 0.835) unlike propionate, which is correlated with fecal calprotectin (r = 0.517), a protein biomarker of intestinal inflammation. Also, a longitudinal study of matching stool samples collected from a sub-set of IBD patients revealed about a 7-fold enrichment in magnesium and calcium following 4 weeks of EEN as compared to baseline (F > 4.1 ; p < 0.05) unlike the CS treatment arm with no changes in other fecal SCFAs and electrolytes, including sodium, potassium, and ammonium. CE-iUV enables rapid fecal SCFA and electrolyte determination as required for new insights into the role of gut dysbiosis in IBD, as well as treatment monitoring of nutritional interventions that stabilize the disease course in affected children.

Optical coherent tomography to evaluate the degree of inflammation in a mouse model of colitis

Background

There is an urgent need to develop a noninvasive imaging technique for the diagnosis of early inflammatory lesions or early and real-time microscopic assessment before selecting the most representative biopsy sites.

Methods

In this study, a dextran sulfate sodium colitis model was developed, and intestinal histological damage scores measured the degree of inflammation in colitis. According to these scores, 6 parameters were designed for hematoxylin and eosin (HE) sections based on morphological changes, and 2 parameters were designed for optical coherence tomography (OCT) images to measure submucosal edema by morphological changes to evaluate inflammation degrees in the colon. Spearman's rank correlation method was used to compare the correlation between the submucosal morphological changes and the different degrees of inflammation. One-way analysis of variance (ANOVA) was used for comparisons among groups, while receiver operating characteristic (ROC) curves of the indicators in HE sections and OCT images were plotted.

Results

In HE sections, angle of mucosal folds (r=0.853, P<0.01), length of basilar parts (r=0.915, P<0.01), submucosal area (r=0.819, P<0.01), and height between submucosal and muscular layers (r=0.451, P=0.001) were correlated with the degree of inflammation in colitis. In OCT images, length of basilar parts (r=0.800, P<0.01) and height of submucosa + thickness of muscularis (r=0.648, P=0.001) were correlated with the degree of inflammation and aided the measurement of inflammation in the colon.

Conclusions

Parameters based on morphological changes in OCT images and HE sections were significant indexes for evaluating the degree of inflammation in colitis. OCT images have advantages for future clinical applications in situ, including noninvasiveness and real-time imaging.

Inhibition of miR-16 Ameliorates Inflammatory Bowel Disease by Modulating Bcl-2 in Mouse Models

BACKGROUND

In recent years, microRNA (miRNA) is considered as a potential therapy target. To study the regulatory mechanism and therapeutic effect of miRNAs on inflammatory bowel disease (IBD), we investigated microRNAs that regulate apoptosis-related protein B cell lymphoma-2 (Bcl-2). We examined the role of miR-16 in IBD and the effect of inhibiting the expression of miR-16 on disease progression.

MATERIALS AND METHODS

Dextran sulfate sodium was used to induce ulcerative colitis in mice. RNA and protein were extracted from the rectal mucosa of mice. Real-time quantitative polymerase chain reaction and Western blotting were used to detect the expression of miR-16 and Bcl-2. The effects of miR-16 on intestinal mucosal immunity were studied by real-time quantitative polymerase chain reaction, and inflammatory factors such as interleukin-1β, interleukin-6, and tumor necrosis factor-α were detected. The weight changes, disease activity index, length of the rectal colon, and pathological score of the mice were used to evaluate the effect of inhibiting miR-16 on disease progression. Through the establishment of overexpression and low expression cell lines of miR-16, the regulation of miR-16 on Bcl-2 was studied.

RESULTS

MiR-16 was overexpressed in the IBD model, whereas Bcl-2 had lower expression in the mucosa. Inhibiting expression of miR-16 significantly decreased the expression of interleukin-1β, interleukin-6, and tumor necrosis factor-α. In mice, the weight change, disease activity index, and pathological score decreased in the experimental group, in which miR-16 was inhibited. High expression of miR-16 can inhibit Bcl-2 expression.

CONCLUSIONS

MiR-16 plays a critical role in IBD via Bcl-2 and is a promising target in IBD therapy.

Approach to the Patient with Axial Spondyloarthritis and Suspected Inflammatory Bowel Disease

To adequately and efficiently evaluate patients with gastrointestinal symptoms in the context of axial spondyloarthritis can be difficult, considering that many of these patients suffer from chronic pain, present high inflammatory parameters, and use drugs with possible gastrointestinal adverse effects. In addition, the immunosuppressive treatments that these patients can receive make it necessary to always consider infections within the differential diagnoses of inflammatory bowel disease. In this article, we propose a practical approach to patients diagnosed with axial spondyloarthritis and suspected inflammatory bowel disease.

Faecal Micro-RNAs in Inflammatory Bowel Diseases

BACKGROUND AND AIMS

Faecal biomarkers are used as indicators of disease activity in inflammatory bowel diseases [IBD], which include Crohn's disease [CD] and ulcerative colitis [UC]. Micro-RNAs [miRNAs] are small non-coding RNAs detectable in extracellular fluids and can be used as clinical biomarkers. The aim of this study was to determine if faecal miRNA composition is altered in IBD.

METHODS

More than 800 different human faecal miRNAs were measured in stool samples from control individuals and patients with active CD by using NanoString technology. Selected miRNAs were quantified by qRT-PCR in faeces, serum and intestinal tissue of controls [n = 23] and patients with inactive or active CD [n = 22, n = 22] or UC [n = 11, n = 24] as well as patients with Clostridium difficile infection [CDI, n = 8].

RESULTS

In total, 150 miRNAs were significantly detected in faeces from controls and patients, and multivariate analyses showed that CD patients with high disease activities had a distinct miRNA profile and that miR-223 and miR-1246 were distinct from other faecal miRNAs. In a larger cohort, active UC patients displayed significantly higher levels of miR-223 and miR-1246 than controls while patients with CDI had higher levels of faecal miR-1246 but not miR-223. No differences were noted in serum samples.

CONCLUSIONS

To our knowledge, this is the first comprehensive screen of faecal miRNAs performed in IBD. Further investigation will aim to confirm these findings in a larger cohort and to understand the biological function and cellular sources of faecal miRNAs.

Quantitative Proteomic Analysis Reveals the Deregulation of Nicotinamide Adenine Dinucleotide Metabolism and CD38 in Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) has become a major health challenge worldwide. However, the precise etiological and pathophysiological factors involved in IBD remain unclear. Proteomics can be used for large-scale protein identification analysis. In the current study, using tandem mass tag- (TMT-) based shotgun proteomics, proteomic differences between intestinal tissue from health controls, patients with Crohn's disease (CD), and patients with ulcerative colitis (UC) were compared. Proteins with fold change >2 or <0.5 and P value < 0.05 between groups were considered differentially expressed. ProteinAtlas was used to analyze the tissue specificity of differentially expressed proteins (DEPs). Reactome pathway analysis was applied to cluster functional pathways. A total of 4786 proteins were identified, with 59 proteins showing higher levels and 43 showing lower levels in patients with IBD than in controls. Seventeen proteins, including angiotensin converting enzyme 2 (ACE2) and angiotensin converting enzyme 1 (ACE), showed higher levels in CD than in UC. Several novel proteins such as CD38, chitinase 3-like 1 (CHI3L1), olfactomedin 4 (OLFM4), and intelectin 1 were screened out between patients with IBD and controls. When proteins with fold change >1.2 or <0.84 and P value < 0.05 between groups were considered differentially expressed, the expression of 10 proteins, including CD38, involved in the nicotinamide adenine dinucleotide (NAD) metabolism and signaling pathway showed significant changes in IBD. Using the NCBI GEO database, we confirmed increased CD38 mRNA expression in patients with UC and in mouse colitis models. Protein CD38 expression was higher in CD and UC than in normal controls. CD38 expression was higher in inflamed tissues than in noninflamed tissues, and CD38 was located in F4/80-positive cells. Our study may provide novel insights into the molecular pathogenesis of IBD. Further studies are required on the role of NAD metabolism and CD38 in intestinal inflammation.

Serum Metabolomics Identifies Altered Bioenergetics, Signaling Cascades in Parallel with Exposome Markers in Crohn's Disease

: Inflammatory bowel disease (IBD) has stimulated much interest due to its surging incidences and health impacts in the U.S. and worldwide. However, the exact cause of IBD remains incompletely understood, and biomarker is lacking towards early diagnostics and effective therapy assessment. To tackle these, the emerging high-resolution mass spectrometry (HRMS)-based metabolomics shows promise. Here, we conducted a pilot untargeted LC/MS metabolomic profiling in Crohn's disease, for which serum samples of both active and inactive cases were collected, extracted, and profiled by a state-of-the-art compound identification workflow. Results show a distinct metabolic profile of Crohn's from control, with most metabolites downregulated. The identified compounds are structurally diverse, pointing to important pathway perturbations ranging from energy metabolism (e.g., β-oxidation of fatty acids) to signaling cascades of lipids (e.g., DHA) and amino acid (e.g., L-tryptophan). Importantly, an integral role of gut microbiota in the pathogenesis of Crohn's disease is highlighted. Xenobiotics and their biotransformants were widely detected, calling for massive exposomic profiling for future cohort studies as such. This study endorses the analytical capacity of untargeted metabolomics for biomarker development, cohort stratification, and mechanistic interpretation; the findings might be valuable for advancing biomarker research and etiologic inquiry in IBD.

Effect of Homocysteine on the Differentiation of CD4+ T Cells into Th17 Cells

BACKGROUND

The hyperhomocysteinaemia (Hhcy) is a common phenomenon observed in patients with inflammatory bowel disease (IBD). Our previous study showed that Hhcy aggravated intestinal inflammation in an animal model of colitis. Increased levels of IL-17 and RORγt were also observed in this animal model of colitis with Hhcy. However, the direct effect of homocysteine on the differentiation of Th17 cells has never been studied. The aim of this study was to investigate the direct effect of Hhcy on the differentiation of CD4⁺ T cells into Th17 cells.

METHOD

Lamina propria lymphocytes (LPLs) in colonic mucosa of Wistar rats were isolated and cultured under Th17-inducing (iTH17) environments. Different concentrations of the Hcy (0-100 μmol/ml) were added alone or combined with IL-23 (100 ng/ml) or folate (5 μmol/ml). The LPLs were divided into eight groups as follows: (1) Control group; (2) 10 μmol/ml Hcy group; (3) 25 μmol/ml Hcy group; (4) 50 μmol/ml Hcy group; (5) 100 μmol/ml Hcy group; (6) 100 ng/ml IL-23 group; (7) 50 μmol/ml Hcy + 100 ng/ml IL-23 group and (8) 50 μmol/ml Hcy + 100 ng/ml IL-23 + 5 μmol/ml folate group. The protein expression levels of IL-17, retinoid-related orphan nuclear receptor-γt (RORγt), p38 MAPK, phosphorylated p38 MAPK, cytosolic phospholipase A2 (cPLA2), phosphorylated-cPLA2 and cyclooxygenase 2 (COX2) were detected by immunoblot analysis. The protein level of prostaglandin E2 (PGE2) and IL-17 was detected by ELISA, and IL-17 and RORγt-positive CD4⁺ T cells were stained and analyzed by flow cytometry.

RESULTS

Hcy increased the protein levels of IL-17, RORγt, the ratio of phosphorylated p38 MAPK to p38 MAPK (p-p38/p38), the ratio of phosphorylated cPLA2 to cPLA2 (p-cPLA2/cPLA2) and COX2. The effect was concentration dependent to a certain degree; Hcy of 50 μmol/ml was the optimal concentration to increase the protein levels of those molecules. The level of IL-17 and PGE2 in the cell culture supernatants and the expression of IL-17 and RORγt in positive CD4⁺ T cells were also increased in the group of Hhcy. IL-23 showed a cooperative effect with Hcy on the differentiation of CD4⁺ Th cells into Th17 cells, whereas folate supplementation showed an inhibition action.

CONCLUSIONS

Homocysteine promoted the differentiation of CD4⁺ T cells into Th17 cells in a dose-dependant manner. This effect could be inhibited by folate.

Palmatine ameliorated murine colitis by suppressing tryptophan metabolism and regulating gut microbiota

Inflammatory bowel disease (IBD), majorly include Crohn's disease (CD) and ulcerative colitis (UC), is chronic and relapsing inflammatory disorders of the gastrointestinal tract, which treatment options remain limited. Here we examined the therapeutic effects of an isoquinoline alkaloid, Palmatine (Pal), on mice experimental colitis induced by dextran sulfate sodium (DSS) and explored underlying mechanisms. Colitis was induced in BALB/c mice by administering 3% DSS in drinking water for 7 days. Pal (50 and 100 mg kg^-1) and the positive drug Sulfasalazine (SASP, 200 mg kg^-1) were orally administered for 7 days. Disease activity index (DAI) was evaluated on day 8, and colonic tissues were collected for biochemistry analysis. The fecal microbiota was characterized by high-throughput Illumina MiSeq sequencing. And plasma metabolic changes were detected by UPLC-MS. Our results showed that Pal treatment significantly reduced DAI scores and ameliorated colonic injury in mice with DSS-induced colitis. Mucosal integrity was improved and cell apoptosis was inhibited. Moreover, gut microbiota analysis showed that mice received Pal-treatment have higher relative abundance of Bacteroidetes and Firmicutes, but reduced amount of Proteobacteria. Moreover, Pal not only suppressed tryptophan catabolism in plasma, but also decreased the protein expression of indoleamine 2,3-dioxygenase 1 (IDO-1, the rate-limiting enzyme of tryptophan catabolism) in colon tissue. This is consolidated by molecular docking, which suggested that Pal is a potent IDO-1 inhibitor. Taken together, our findings demonstrate that Pal ameliorated DSS-induced colitis by mitigating colonic injury, preventing gut microbiota dysbiosis, and regulating tryptophan catabolism, which indicated that Pal has great therapeutic potential for colitis.

Plasma N-Glycan Signatures Are Associated With Features of Inflammatory Bowel Diseases

BACKGROUND & AIMS

Biomarkers are needed for early detection of Crohn's disease (CD) and ulcerative colitis (UC) or to predict patient outcomes. Glycosylation is a common and complex posttranslational modification of proteins that affects their structure and activity. We compared plasma N-glycosylation profiles between patients with CD or UC and healthy individuals (controls).

METHODS

We analyzed the total plasma N-glycomes of 2635 patients with inflammatory bowel diseases and 996 controls by mass spectrometry with a linkage-specific sialic acid derivatization technique. Plasma samples were acquired from 2 hospitals in Italy (discovery cohort, 1989 patients with inflammatory bowel disease [IBD] and 570 controls) and 1 medical center in the United States (validation cohort, 646 cases of IBD and 426 controls). Sixty-three glycoforms met our criteria for relative quantification and were extracted from the raw data with the software MassyTools. Common features shared by the glycan compositions were combined in 78 derived traits, including the number of antennae of complex-type glycans and levels of fucosylation, bisection, galactosylation, and sialylation. Associations of plasma N-glycomes with age, sex, CD, UC, and IBD-related parameters such as disease location, surgery and medication, level of C-reactive protein, and sedimentation rate were tested by linear and logistic regression.

RESULTS

Plasma samples from patients with IBD had a higher abundance of large-size glycans compared with controls, a decreased relative abundance of hybrid and high-mannose structures, lower fucosylation, lower galactosylation, and higher sialylation (α2,3- and α2,6-linked). We could discriminate plasma from patients with CD from that of patients with UC based on higher bisection, lower galactosylation, and higher sialylation (α2,3-linked). Glycosylation patterns were associated with disease location and progression, the need for a more potent medication, and surgery. These results were replicated in a large independent cohort.

CONCLUSIONS

We performed high-throughput analysis to compare total plasma N-glycomes of individuals with vs without IBD and to identify patterns associated with disease features and the need for treatment. These profiles might be used in diagnosis and for predicting patients' responses to treatment.

Glycosylation of Immunoglobulin G Associates With Clinical Features of Inflammatory Bowel Diseases

BACKGROUND AND AIMS

Causes of inflammatory bowel diseases are not well understood and the most prominent forms, Crohn's disease (CD) and ulcerative colitis (UC), are sometimes hard to distinguish. Glycosylation of IgG has been associated with CD and UC. IgG Fc-glycosylation affects IgG effector functions. We evaluated changes in IgG Fc-glycosylation associated with UC and CD, as well as with disease characteristics in different patient groups.

METHODS

We analyzed 3441 plasma samples obtained from 2 independent cohorts of patients with CD (874 patients from Italy and 391 from the United States) or UC (1056 from Italy and 253 from the US and healthy individuals [controls]; 427 in Italy and 440 from the United States). IgG Fc-glycosylation (tryptic glycopeptides) was analyzed by liquid chromatography coupled to mass spectrometry. We analyzed associations between disease status (UC vs controls, CD vs controls, and UC vs CD) and glycopeptide traits, and associations between clinical characteristics and glycopeptide traits, using a logistic regression model with age and sex included as covariates.

RESULTS

Patients with CD or UC had lower levels of IgG galactosylation than controls. For example, the odds ratio (OR) for IgG1 galactosylation in patients with CD was 0.59 (95% confidence interval [CI], 0.51-0.69) and for patients with UC was 0.81 (95% CI, 0.71-0.92). Fucosylation of IgG was increased in patients with CD vs controls (for IgG1: OR, 1.27; 95% CI, 1.12-1.44), but decreased in patients with UC vs controls (for IgG23: OR, 0.72; 95% CI, 0.63-0.82). Decreased galactosylation associated with more severe CD or UC, including the need for surgery in patients with UC vs controls (for IgG1: OR, 0.69; 95% CI, 0.54-0.89) and in patients with CD vs controls (for IgG23: OR, 0.78; 95% CI, 0.66-0.91).

CONCLUSIONS

In a retrospective analysis of plasma samples from patients with CD or UC, we associated levels of IgG Fc-glycosylation with disease (compared to controls) and its clinical features. These findings could increase our understanding of mechanisms of CD and UC pathogenesis and be used to develop diagnostics or guide treatment.

A Distinctive Urinary Metabolomic Fingerprint Is Linked With Endoscopic Postoperative Disease Recurrence in Crohn's Disease Patients

BACKGROUND

Crohn's disease (CD) patients who undergo ileocolonic resection frequently have disease recurrence. The aim of this preliminary study was to identify urinary metabolomic profiles associated with disease recurrence in order to identify underlying mechanisms of recurrence and possible disease biomarkers.

METHODS

Biopsies from the neoterminal ileum were collected from CD patients (n = 38) after ileocolonic resection in order to assess mucosa-associated microbiota using 16S rRNA multitag pyrosequencing. Urine samples were collected, and metabolomic profiling was done using high-resolution nuclear magnetic resolution spectroscopy and a combined direct infusion liquid chromatography tandem mass spectrometry. The Rutgeerts scoring system was used to assess endoscopic postoperative recurrence of CD.

RESULTS

There were 28 (73.7%) patients with endoscopic CD recurrence. CD patients who were in endoscopic remission had a higher abundance of Bacteroidetes and lower abundance of Fusobacteria and Proteobacteria in comparison with CD patients who had endoscopic recurrence. In addition, metabolomic profiling could also discriminate between these 2 groups of patients. Endoscopic recurrence was associated with increased concentration of urinary levoglucosan. Rutgeerts score was positively correlated with levoglucosan and propylene glycol levels.

CONCLUSIONS

CD patients who present with endoscopic disease recurrence after surgery have a unique urinary metabolomic fingerprint that can differentiate them from CD patients who are in endoscopic remission after ileocolonic resection. In addition, mucosal-associated microbiota in CD patients with or without disease recurrence after surgery differs and correlates with some urinary metabolites.

Patchouli alcohol ameliorates dextran sodium sulfate-induced experimental colitis and suppresses tryptophan catabolism

Despite the increased morbidity of ulcerative colitis (UC) in recent years, available treatments remain unsatisfactory. Pogostemon cablin has been widely applied to treat a variety of gastrointestinal disorders in clinic for centuries, in which patchouli alcohol (PA, C₁₅H₂₆O) has been identified as the major active component. This study attempted to determine the bioactivity of PA on dextran sulfate sodium (DSS)-induced mice colitis and clarify the mechanism of action. Acute colitis was induced in mice by 3% DSS for 7 days. The mice were then given PA (10, 20 and 40mg/kg) or sulfasalazine (SASP, 200mg/kg) as positive control via oral administration for 7 days. At the end of study, animals were sacrificed and samples were collected for pathological and other analysis. In addition, a metabolite profiling and a targeted metabolite analysis, based on the Ultra-Performance Liquid Chromatography coupled with mass spectrometry (UPLC-MS) approach, were performed to characterize the metabolic changes in plasma. The results revealed that PA significantly reduced the disease activity index (DAI) and ameliorated the colonic injury of DSS mice. The levels of colonic MPO and cytokines involving TNF-α, IFN-γ, IL-1β, IL-6, IL-4 and IL-10 also declined. Furthermore, PA improved the intestinal epithelial barrier by enhancing the level of colonic expression of the tight junction (TJ) proteins, for instance ZO-1, ZO-2, claudin-1 and occludin, and by elevating the levels of mucin-1 and mucin-2 mRNA. The study also demonstrated that PA inhibited the DSS-induced cell death signaling by modulating the apoptosis related Bax and Bcl-2 proteins and down-regulating the necroptosis related RIP3 and MLKL proteins. By comparison, up-regulation of IDO-1 and TPH-1 protein expression in DSS group was suppressed by PA, which was in line with the declined levels of kynurenine (Kyn) and 5-hydroxytryptophan (5-HTP) in plasma. The therapeutic effect of PA was evidently reduced when Kyn was given to mice. In summary, the study successfully demonstrated that PA ameliorated DSS-induced mice acute colitis by suppressing inflammation, maintaining the integrity of intestinal epithelial barrier, inhibiting cell death signaling, and suppressing tryptophan catabolism. The results provided valuable information and guidance for using PA in treatment of UC.

Utility of Biomarkers in the Management of Inflammatory Bowel Disease

OPINION STATEMENT

Inflammatory bowel disease (IBD) is comprised of complex clinical and pathological conditions. It runs a chronic course, and proper management requires constant monitoring of disease activity. Recent evidence suggests that subjective patient scores have a poor correlation with disease activity. Endoscopy remains the gold standard for diagnosing and monitoring disease activity. As healthcare is moving towards less costly and less invasive treatments, the need for biomarkers in the management of IBD is evident. Over the last decade, several biomarkers have been found, which may correct the discrepancy between subjective patient scores and the need for endoscopy.

miRNA-133a-UCP2 pathway regulates inflammatory bowel disease progress by influencing inflammation, oxidative stress and energy metabolism

AIM

To investigate the role of the miR-133a-UCP2 pathway in the pathogenesis of inflammatory bowel disease (IBD) and to explore the potential downstream mechanisms with respect to inflammation, oxidative stress and energy metabolism.

METHODS

C57BL/6 mice were fed dextran sulfate sodium (DSS) liquid for 7 consecutive days, followed by the administration of saline to the DSS group, UCP2 siRNA to the UCP2 group and a miR-133a mimic to the miR-133a group on days 8 and 11. Body weight, stool consistency and rectal bleeding were recorded daily, and these composed the disease activity index (DAI) score for the assessment of disease severity. After cervical dislocation was performed on day 14, the length of the colon in each mouse was measured, and colonic tissue was collected for further study, which included the following: haematoxylin and eosin staining, UCP2 and miR-133a detection by immunohistochemical staining, western blot and quantitative real-time PCR, measurement of apoptosis by TUNEL assay, and the assessment of inflammation (TNF-α, IL-1β, IL-6 and MCP1), oxidative stress (H₂O₂ and MDA) and metabolic parameters (ATP) by ELISA and colorimetric methods.

RESULTS

An animal model of IBD was successfully established, as shown by an increased DAI score, shortened colon length and specific pathologic changes, along with significantly increased UCP2 and decreased miR-133a levels. Compared with the DSS group, the severity of IBD was alleviated in the UCP2 and the miR-133a groups after successful UCP2 knockdown and miR-133a overexpression. The extent of apoptosis, as well as the levels of TNF-α, IL-1β, MDA and ATP, were significantly increased in both the UCP2 and miR-133a groups compared with the DSS group.

CONCLUSION

The miR-133a-UCP2 pathway participates in IBD by altering downstream inflammation, oxidative stress and markers of energy metabolism, which provides novel clues and potential therapeutic targets for IBD.