Biomarkers In Inflammatory Bowel Disease Research Articles

The role of fecal matrix metalloprotease-9 as a non-invasive marker in diagnosis and assessment of clinical activity in inflammatory bowel disease patients

BackgroundInflammatory bowel disease is characterized by chronic and relapsing inflammation of the gastrointestinal tract, including two prominent forms: Crohn’s disease and ulcerative colitis. Determining diagnostic biomarkers for predicting disease activity and treatment response remains a challenging aspect.Aim of the workThe purpose of our research was to compare fecal CP and fecal MMP-9, two non-invasive biomarkers for inflammatory bowel disease (IBD), and to find out how fecal MMP-9 levels relate to disease activity by looking at how they relate to clinical, endoscopic, and histologic scores of disease activity.Patients and methodsThis study was performed on 80 subjects divided into 3 groups: group A: 30 patients with Crohn’s disease evidenced by endoscopy ileocolonoscopy, upper GI endoscopy, and tissue biopsy (15 patients with active disease and 15 patients in remission). Group B: 30 patients with ulcerative colitis disease evidenced by colonoscopy and tissue biopsy (15 patients with active disease and 15 patients in remission). Group C: 20 age-matched and sex-matched healthy controls. All participants underwent a thorough history review, comprehensive physical examination, complete laboratory tests, and C-reactive protein measurements. A quantitative enzyme-linked immunosorbent assay was used to determine the levels of fecal matrix metalloproteinase MMP 9 for both the patients and the controls. Ulcerative colitis was evaluated using the Mayo score, Montreal classification, and the Riley histological score. Additionally, Crohn’s disease was assessed with the Crohn’s Disease Activity Index, the Simple Endoscopic Score for Crohn’s Disease, and the D’Haens histological score.ResultsComparing fecal MMP-9 with fecal calprotectin (FC), we found that fecal MMP-9 was superior to FC in differentiating active Crohn’s disease from inactive Crohn’s disease, although there was no significant difference between FC and MMP-9 (P-value = 0.561). However, in ulcerative colitis, FC was superior to MMP-9 in distinguishing active UC from inactive UC, but again, there was no significant difference between FC and MMP-9 (P-value = 0.0731).In both the ulcerative colitis and Crohn’s disease groups, fecal MMP-9 could discriminate between patients in remission and those with active disease. Fecal matrix metalloproteinase-9 (MMP-9) was discovered to be a significant marker for assessing the clinical activity of both Crohn’s disease (CD) and ulcerative colitis (UC), with an AUC of 0.998 for CD and 0.991 for UC. Fecal MMP-9 demonstrated great sensitivity (93.33%), specificity (100%), positive predictive value (PPV) of 100%, and negative predictive value (NPV) of 93.7% (with a P-value < 0.001) using cutoff values of > 0.34 ng/mL for CD and > 0.36 ng/mL for UC. There was a strong positive correlation between fecal MMP-9 and endoscopic and clinical scores of disease activity.ConclusionFecal MMP-9 has emerged as a promising biomarker for evaluating the clinical activity of both Crohn’s disease and ulcerative colitis. It demonstrated superior diagnostic performance compared to fecal calprotectin in distinguishing active from inactive disease, especially in Crohn’s disease. Although fecal calprotectin outperformed MMP-9 in identifying active ulcerative colitis, the differences between the two markers were not statistically significant, suggesting that they may complement each other in clinical practice. Furthermore, fecal MMP-9 is capable of assessing the activity of endoscopically visible inflammatory bowel disease (IBD), which could help reduce the need for invasive endoscopic procedures.

The circulating methylome in childhood-onset inflammatory bowel disease.

The genetic contribution to inflammatory bowel disease (IBD) encompassing both Crohn's disease (CD) and ulcerative colitis (UC), accounts for around 20% of disease variance, highlighting the need to characterise environmental and epigenetic influences. Recently considerable progress has been made in characterising the adult methylome, in epigenome-wide association studies. We report detailed analysis of the circulating methylome in 86 patients with childhood-onset CD,UC and 30 controls using the Illumina Infinium Human MethylationEPIC platform. We derive and validate a 4-probe methylation biomarker (RPS6KA2, VMP1, CFI and ARHGEF3), with specificity and high diagnostic accuracy for paediatric IBD in UK and North American cohorts (AUC 0.90-0.94). Significant epigenetic age acceleration is present at diagnosis, with the greatest observed in CD patients. Cis-MeQTL analysis identifies genetic determinants underlying epigenetic alterations notably within the HLA 6p22.1-p21.33 region. Passive smoking exposure is associated with the development of UC rather than CD contrary to previous findings. These data provide new insights into epigenetic alterations in IBD and illustrate the reproducibility and translational potential of epigenome-wide association studies in complex diseases.

Oxidative stress-related biomarkers as promising indicators of inflammatory bowel disease activity: A systematic review and meta-analysis

Oxidative stress is believed to play an important role in the pathogenesis of inflammatory bowel disease (IBD), specifically Crohn's disease (CD) and ulcerative colitis (UC). This meta-analysis aimed to identify and quantify the oxidative stress-related biomarkers in IBD and their associations with disease activity. We systematically searched Ovid MEDLINE, Ovid Embase, and Web of Science databases, identifying 54 studies for inclusion. Comparisons included: (i) active IBD versus healthy controls; (ii) inactive IBD versus healthy controls; (iii) active CD versus inactive CD; and (iv) active UC versus inactive UC. Our analysis revealed a significant accumulation of biomarkers of oxidative damage to biomacromolecules, coupled with reductions in various antioxidants, in both patients with active and inactive IBD compared to healthy controls. Additionally, we identified biomarkers that differentiate between active and inactive CD, including malondialdehyde, Paraoxonase 1, catalase, albumin, transferrin, and total antioxidant capacity. Similarly, levels of Paraoxonase 1, erythrocyte glutathione peroxidase, catalase, albumin, transferrin, and free thiols differed between active and inactive UC. Vitamins and carotenoids also emerged as potential disease activity biomarkers for CD and UC, but their intake should be monitored to obtain meaningful results. These findings emphasize the involvement of oxidative stress in the pathogenesis of IBD and highlight the potential of oxidative stress-related biomarkers as a minimally invasive and additional tool for monitoring the activity of IBD.

Identification and Validation of Biomarkers to Predict Early Diagnosis of Inflammatory Bowel Disease and Its Progression to Colorectal Cancer.

Inflammatory bowel disease (IBD) has become a common global health problem as prevalence continues to rise. It is often associated with increased risk of colorectal cancer (CRC) development. Limitations in current IBD biomarker-based diagnosis hinder the accuracy of early detection of CRC progression. Therefore, in this study, we proposed the use of transcription factor (TF)-based biomarkers that can potentially detect the transition of IBD to CRC. Various bioinformatic analysis and online database validations, and RT-qPCR validations were performed to identify possible diagnostic TFs. RUNX1 was identified as a promising TF that regulates 106 IBD/CRC-related genes. The incorporation of RUNX1 in combination with currently known IBD biomarkers, FEV + NFKB1 + RELA, achieved a comparable sensitivity and specificity scores of 99% and 87%, respectively, while RUNX1 in combination with known CRC markers, CEA + TIMP1 + CA724 + CA199, achieved a sensitivity and specificity score of 97% and 99%, respectively. Furthermore, a small pilot RT-qPCR-based analysis confirmed a demarcated shift in expression profiles in CA724, CEA, RUNX1 and TIMP1 in IBD patients compared to CRC patients' tissue samples. Specifically, CA724 is noticeably elevated in IBD, while the levels of CEA, RUNX1 with TIMP1 are probable genes that may be employed in discerning IBD progression to CRC. Therefore, these preliminary results once validated in large patient cohorts could potentially have a significant impact on CRC disease stratification, resulting in a more precise prediction for treatment and treatment outcomes, especially in South African patients.

Biochemical Modulators of Tight Junctions (TJs): Occludin, Claudin-2 and Zonulin as Biomarkers of Intestinal Barrier Leakage in the Diagnosis and Assessment of Inflammatory Bowel Disease Progression.

Considering the increasing worldwide prevalence of inflammatory bowel disease (IBD), the early diagnosis of this disease is extremely important. However, non-invasive diagnostic methods remain limited, while invasive techniques are the most commonly used in daily practice. Therefore, there is a serious need to find new non-invasive biomarkers of IBD. The serum profiles of occludin, claudin-2, and zonulin were assessed in IBD patients using the ELISA method. The levels of the analyzed biomarkers were measured before and after a year of anti-inflammatory treatment, which was a tumor necrosis factor α (TNF-α) inhibitor (adalimumab) in patients with ulcerative colitis (UC) and conventional therapy in patients with Crohn's disease (CD). In IBD patients, the serum level of occludin (p < 0.001) decreased compared to healthy individuals, while the level of claudin-2 (p < 0.001) increased. Additionally, zonulin (p < 0.01) concentration increased in CD patients compared to the control group. The highest diagnostic ability was presented by occludin measurements with the area under the curve (AUC) of 0.959 (95% CI 0.907-1) in UC and 0.948 (95% CI 0.879-1) in CD. Claudin-2 also demonstrated very good ability in diagnosing UC and CD with AUC values of 0.864 (95% CI 0.776-0.952) and 0.896 (95% CI 0.792-0.999), respectively. The ability of zonulin to diagnose CD was estimated as good with an AUC of 0.74 (95% CI 0.598-0.881). Moreover, a significant correlation was identified between C-reactive protein (CRP), claudin-2 (r = -0.37; p < 0.05), and zonulin (r = -0.44; p < 0.05) in UC patients. Treatment with adalimumab improved the level of occludin, claudin-2, and zonulin in UC patients, while anti-inflammatory conventional therapy decreased the concentration of zonulin in CD. Occludin and claudin-2 measurements present significant utility in diagnosing both UC and CD, while zonulin assessments may be useful in CD diagnosis. Additionally, claudin-2 and zonulin measurements may be helpful in evaluating the intensity of the inflammatory process. Anti-TNF-α treatment improved the value of occludin, claudin-2, and zonulin, indicating its beneficial effect on the integrity of tight junctions in UC.

Stromal-Like Cells Are Found in Peripheral Blood of Patients With Inflammatory Bowel Disease and Correlate With Immune Activation State.

Recent studies have identified a critical role of stromal-immune cell interactions in immunity and immune tolerance. Transcriptomic profiling has implicated stromal cells in immune-mediated disorders including the 2 common forms of inflammatory bowel disease (IBD), Crohn's disease (CD), and ulcerative colitis (UC). Stromal-immune interactions may edify inflammatory state and the development of IBD-related complications such as fibrosis, yet the lack of protein markers has hampered studying stromal-immune perturbation. In this study, we designed a 40-color spectral flow cytometry assay to characterize hematopoietic and nonhematopoietic cells in intestinal biopsies and matched blood samples from patients with CD or UC. We identified circulating stromal-like cells that are significantly more abundant in IBD blood samples than in healthy controls. Those cells expressed podoplanin (PDPN), a commonly used marker for fibroblasts, and they were associated with activated and memory T and B cells and altered natural killer cell, monocyte, and macrophage populations. PDPN + cells in the blood correlated with PDPN + cells in the colon. Principal component analysis distinctly separated healthy blood samples from IBD blood samples, with stromal-like cells and B-cell subtypes dominating the IBD signature; Pearson correlation detected an association between PDPN + stromal-like cells and B-cell populations in IBD blood and gut biopsies. These observations suggest that PDPN + cells in the blood may serve as a biomarker of IBD. Understanding the relationship between stromal cells and immune cells in the intestine and the blood may provide a window into disease pathogenesis and insight into therapeutic targets for IBD.

Bioinformatics analysis-based mining of potential markers for inflammatory bowel disease and their immune relevance.

The incidence of inflammatory bowel disease (IBD) is increasing every year and is characterized by a prolonged course, frequent relapses, difficulty in curing, and a lack of more efficacious therapeutic biomarkers. The aim of this study was to find key core genes as therapeutic biomarkers for IBD. GSE75214 in Gene Expression Omnibus (GEO) was used as the experimental set. The genes in the top 25% of standard deviation of all samples in the experimental set were subjected to systematic weighted gene co-expression network analysis (WGCNA) to find candidate genes. Then, least absolute shrinkage and selection operator (LASSO) logistic regression was used to further screen the central genes. Finally, the validity of hub genes was verified on GEO dataset GSE179285 using "BiocManager" R package. Twelve well-preserved modules were identified in the experimental set using the WGCNA method. Among them, five modules significantly associated with IBD were screened as clinically significant modules, and four candidate genes were screened from these five modules. Then TIMP1, GUCA2B, and HIF1A were screened as hub genes. These hub genes successfully distinguished tumor samples from healthy tissues by artificial neural network algorithm in an independent test set with an area under the working characteristic curve of 0.946 for the subjects. IBD differentially expressed gene (DEGs) are involved in immunoregulatory processes. TIMP1, GUCA2B, and HIF1A, as core genes of IBD, have the potential to be therapeutic targets for patients with IBD, and our findings may provide a new outlook on the future treatment of IBD.

Gut Microbiota Profiling as a Promising Tool to Detect Equine Inflammatory Bowel Disease (IBD).

Gastrointestinal disorders are common and debilitating in horses, but their diagnosis is often difficult and invasive. Fecal samples offer a non-invasive alternative to assessing the gastrointestinal health of horses by providing information about the gut microbiota and inflammation. In this study, we used 16S sequencing to compare the fecal bacterial diversity and composition of 27 healthy horses and 49 horses diagnosed with inflammatory bowel disease (IBD). We also measured fecal calprotectin concentration, a marker of intestinal inflammation, in healthy horses and horses with IBD. We found that microbiota composition differed between healthy horses and horses with IBD, although less than five percent of the variation in microbiota composition was explained by individual health status and age. Several differentially abundant bacterial taxa associated with IBD, age, or body condition were depleted from the most dominant Firmicutes phylum and enriched with the Bacteroidota phylum. An artificial neural network model predicted the probability of IBD among the test samples with 100% accuracy. Our study is the first to demonstrate the association between gut microbiota composition and chronic forms of IBD in horses and highlights the potential of using fecal samples as a non-invasive source of biomarkers for equine IBD.

Long Non-Coding RNAs and Their Potential Role as Biomarkers in Inflammatory Bowel Disease.

Inflammatory bowel disease is a chronic inflammatory disease that encompasses entities such as Crohn's disease and ulcerative colitis. Its incidence has risen in newly industrialised countries over time, turning it into a global disease. Lately, studies on inflammatory bowel disease have focused on finding non-invasive and specific biomarkers. Long non-coding RNAs may play a role in the pathophysiology of inflammatory bowel disease and therefore they may be considered as potential biomarkers for this disease. In the present article, we review information in the literature on the relationship between long non-coding RNAs and inflammatory bowel disease. We especially focus on understanding the potential function of these RNAs as non-invasive biomarkers, providing information that may be helpful for future studies in the field.

Faecal biomarkers for diagnosis and prediction of disease course in treatment-naïve patients with IBD.

Faecal biomarkers can be used to assess inflammatory bowel disease (IBD). To explore the performance of some promising biomarkers in diagnosing and predicting disease course in IBD. We included 65 patients with treatment-naïve, new-onset Crohn's disease (CD), 90 with ulcerative colitis (UC), 67 symptomatic controls (SC) and 41 healthy controls (HC) in this prospective observational study. We analysed faecal samples for calprotectin (FC), myeloperoxidase (MPO), human neutrophil lipocalin (HNL), eosinophil cationic protein ECP and eosinophil-derived neurotoxin (EDN) and compared markers among groups. We assessed the diagnostic capability of biomarkers with receiver operating characteristic curves. Clinical disease course was determined for each patient with IBD and analysed the association with biomarkers by logistic regression. All markers were elevated at inclusion in patients with IBD compared with HC (p < 0.001) and SC (p < 0.001). FC (AUC 0.85, 95% CI: 0.79-0.89) and MPO (AUC 0.85, 95% CI: 0.80-0.89) showed the highest diagnostic accuracy in distinguishing IBD from SC. The diagnostic ability of biomarkers differed between IBD subtypes with the highest performance for FC and MPO in CD. The diagnostic accuracy was further improved by combining FC and MPO (p = 0.02). Levels of FC, MPO and HNL at inclusion were predictive of an aggressive disease course with MPO showing the strongest association (p = 0.006). This studyprovides new insight into the diagnostic and prognostic capability of neutrophil and eosinophil biomarkers in IBD and suggests that MPO, alone or in combination with FC, may add to the diagnostic power of faecal biomarkers.

Therapeutic potential of the secreted Kazal-type serine protease inhibitor SPINK4 in colitis

Mucus injury associated with goblet cell (GC) depletion constitutes an early event in inflammatory bowel disease (IBD). Using single-cell sequencing to detect critical events in mucus dysfunction, we discover that the Kazal-type serine protease inhibitor SPINK4 is dynamically regulated in colitic intestine in parallel with disease activities. Under chemically induced colitic conditions, the grim status in Spink4-conditional knockout mice is successfully rescued by recombinant murine SPINK4. Notably, its therapeutic potential is synergistic with existing TNF-α inhibitor infliximab in colitis treatment. Mechanistically, SPINK4 promotes GC differentiation using a Kazal-like motif to modulate EGFR-Wnt/β-catenin and -Hippo pathways. Microbiota-derived diacylated lipoprotein Pam2CSK4 triggers SPINK4 production. We also show that monitoring SPINK4 in circulation is a reliable noninvasive technique to distinguish IBD patients from healthy controls and assess disease activity. Thus, SPINK4 serves as a serologic biomarker of IBD and has therapeutic potential for colitis via intrinsic EGFR activation in intestinal homeostasis.

Ribonuclease 4 functions as an intestinal antimicrobial protein to maintain gut microbiota and metabolite homeostasis

Antimicrobial proteins contribute to host-microbiota interactions and are associated with inflammatory bowel disease (IBD), but our understanding on antimicrobial protein diversity and functions remains incomplete. Ribonuclease 4 (Rnase4) is a potential antimicrobial protein with no known function in the intestines. Here we find that RNASE4 is expressed in intestinal epithelial cells (IEC) including Paneth and goblet cells, and is detectable in human and mouse stool. Results from Rnase4-deficient mice and recombinant protein suggest that Rnase4 kills Parasutterella to modulate intestinal microbiome, thereby enhancing indoleamine-2,3-dioxygenase 1 (IDO1) expression and subsequently kynurenic and xanthurenic acid production in IECs to reduce colitis susceptibility. Furthermore, deceased RNASE4 levels are observed in the intestinal tissues and stool from patients with IBD, correlating with increased stool Parasutterella. Our results thus implicate Rnase4 as an intestinal antimicrobial protein regulating gut microbiota and metabolite homeostasis, and as a potential diagnostic biomarker and therapeutic target for IBD.

Evaluation of the Role of Serum Calprotectin in the Follow Up of Egyptian Inflammatory Bowel Disease Patients

Abstract Background The term inflammatory bowel disease (IBD) describes disorders in which the intestines be inflamed. It has often been thought that they are due to an autoimmune disease. Two major types of IBD are ulcerative colitis (UC) and Crohn's disease (CD). UC is limited to the colon. CD can involve every part of the gastrointestinal tract from the mouth to the anus. Objective To compare between serum and faecal calprotectin regarding their role in follow up of disease activity in inflammatory bowel disease patients. Patients and Methods An observational cross-sectional study was conducted on 25 patients admitted to Tropical medicine department, Ain Shams University Hospitals. Results Calprotectin is highly resistant to proteolysis and can hold in the stool sample for up to 7 days at room temperature. Higher levels of serum calprotectin were linked to a severe inflammatory state in the colon as well as significant clinical symptoms in UC patients. Also, serum calprotectin, CRP, and ESR levels were compared to IBD activity and it was detected that serum calprotectin levels had more sensitivity and specificity than CRP and ESR in identifying IBD activity. Serum calprotectin levels in patients with IBD activity either UC or CD groups, were considerably more than in remission. SC and FC levels were higher levels in clinically active IBD comparing with inactive IBD. Conclusion Serum calprotectin levels are higher in patients with IBD and are related to clinical activity. High serum calprotectin levels can distinguish between patients who are clinically active and those who are in remission in both UC and CD groups. Our findings show that serum calprotectin may be a promising simple diagnostic and prognostic biomarker for IBD however more research is needed to reach a judgment in this regard.

Fecal, Blood, and Urinary Biomarkers in Inflammatory Bowel Diseases

Fecal, Blood, and Urinary Biomarkers in Inflammatory Bowel Diseases

Fecal, Blood, and Urinary Biomarkers in Inflammatory Bowel Diseases

Fecal, Blood, and Urinary Biomarkers in Inflammatory Bowel Diseases

Urinary Hydroxyproline as an Inflammation-Independent Biomarker of Inflammatory Bowel Disease

Urinary Hydroxyproline as an Inflammation-Independent Biomarker of Inflammatory Bowel Disease

Role of long non-coding RNA in inflammatory bowel disease.

Inflammatory bowel disease (IBD) is a group of recurrent chronic inflammatory diseases, including Crohn's disease (CD) and ulcerative colitis (UC). Although IBD has been extensively studied for decades, its cause and pathogenesis remain unclear. Existing research suggests that IBD may be the result of an interaction between genetic factors, environmental factors and the gut microbiome. IBD is closely related to non-coding RNAs (ncRNAs). NcRNAs are composed of microRNA(miRNA), long non-coding RNA(lnc RNA) and circular RNA(circ RNA). Compared with miRNA, the role of lnc RNA in IBD has been little studied. Lnc RNA is an RNA molecule that regulates gene expression and regulates a variety of molecular pathways involved in the pathbiology of IBD. Targeting IBD-associated lnc RNAs may promote personalized treatment of IBD and have therapeutic value for IBD patients. Therefore, this review summarized the effects of lnc RNA on the intestinal epithelial barrier, inflammatory response and immune homeostasis in IBD, and summarized the potential of lnc RNA as a biomarker of IBD and as a predictor of therapeutic response to IBD in the future.

Advances in Inflammatory Bowel Disease Diagnostics: Machine Learning and Genomic Profiling Reveal Key Biomarkers for Early Detection.

This study, utilizing high-throughput technologies and Machine Learning (ML), has identified gene biomarkers and molecular signatures in Inflammatory Bowel Disease (IBD). We could identify significant upregulated or downregulated genes in IBD patients by comparing gene expression levels in colonic specimens from 172 IBD patients and 22 healthy individuals using the GSE75214 microarray dataset. Our ML techniques and feature selection methods revealed six Differentially Expressed Gene (DEG) biomarkers (VWF, IL1RL1, DENND2B, MMP14, NAAA, and PANK1) with strong diagnostic potential for IBD. The Random Forest (RF) model demonstrated exceptional performance, with accuracy, F1-score, and AUC values exceeding 0.98. Our findings were rigorously validated with independent datasets (GSE36807 and GSE10616), further bolstering their credibility and showing favorable performance metrics (accuracy: 0.841, F1-score: 0.734, AUC: 0.887). Our functional annotation and pathway enrichment analysis provided insights into crucial pathways associated with these dysregulated genes. DENND2B and PANK1 were identified as novel IBD biomarkers, advancing our understanding of the disease. The validation in independent cohorts enhances the reliability of these findings and underscores their potential for early detection and personalized treatment of IBD. Further exploration of these genes is necessary to fully comprehend their roles in IBD pathogenesis and develop improved diagnostic tools and therapies. This study significantly contributes to IBD research with valuable insights, potentially greatly enhancing patient care.

Assessing seasonal variations of biomarkers in inflammatory bowel disease.

Inflammatory bowel diseases are chronic pathologies characterized by a complex interplay of genetic and environmental factors, as well as aberrant immune responses. This study aimed to investigate inflammation markers' seasonality and association with disease exacerbation episodes in patients with Crohn's disease and ulcerative colitis. 284 patients were classified based on clinical, endoscopic, and histopathological criteria. Systemic inflammation was evaluated using C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), and chitotriosidase, while fecal calprotectin was measured to assess intestinal inflammation. Serum vitamin D levels and the seasonality of an activity score that combines several clinical and biological parameters were also evaluated. The peak number of patients reporting endoscopic activity occurred in autumn for Crohn's disease (82%) and spring for ulcerative colitis (95%). Regarding histological activity, spring saw the highest number of patients for both diseases (72% for Crohn's disease; 87% for ulcerative colitis). Most of the inflammatory markers exhibited lower values during winter. Systemic inflammatory markers follow a slightly different trend than fecal calprotectin and differ in the two pathologies. The maximum values of intestinal inflammation were observed in autumn for Crohn's disease (784 µg/g) and in spring for ulcerative colitis (1269 µg/g). Serum vitamin D concentrations were consistently low throughout the year. Statistical analysis revealed differences between the seasons for CRP and ESR (P < 0.05). The evolution of flares and inflammatory markers in Crohn's disease and ulcerative colitis displayed distinct seasonal patterns. Systemic inflammation did not consistently parallel intestinal inflammation.

Effects of DNA methylation and its application in inflammatory bowel disease (Review).

Inflammatory bowel disease (IBD) is marked by persistent inflammation, and its development and progression are linked to environmental, genetic, immune system and gut microbial factors. DNA methylation (DNAm), as one of the protein modifications, is a crucial epigenetic process used by cells to control gene transcription. DNAm is one of the most common areas that has drawn increasing attention recently, with studies revealing that the interleukin (IL)‑23/IL‑12, wingless‑related integration site, IL‑6‑associated signal transducer and activator of transcription 3, suppressor of cytokine signaling 3 and apoptosis signaling pathways are involved in DNAm and in the pathogenesis of IBD. It has emerged that DNAm‑associated genes are involved in perpetuating the persistent inflammation that characterizes a number of diseases, including IBD, providing a novel therapeutic strategy for exploring their treatment. The present review discusses DNAm‑associated genes in the pathogenesis of IBD and summarizes their application as possible diagnostic, prognostic and therapeutic biomarkers in IBD. This may provide a reference for the particular form of IBD and its related methylation genes, aiding in clinical decision‑making and encouraging therapeutic alternatives.