DNA methylation-associated colonic mucosal immune and defense responses in treatment-na?ve pediatric ulcerative colitis

Inflammatory bowel diseases (IBD) are emerging globally, indicating that environmental factors may be important in their pathogenesis. Colonic mucosal epigenetic changes, such as DNA methylation, can occur in response to the environment and have been implicated in IBD pathology. However, mucosal DNA methylation has not been examined in treatment-naïve patients. We studied DNA methylation in untreated, left sided colonic biopsy specimens using the Infinium HumanMethylation450 BeadChip array. We analyzed 22 control (C) patients, 15 untreated Crohn’s disease (CD) patients, and 9 untreated ulcerative colitis (UC) patients from two cohorts. Samples obtained at the time of clinical remission from two of the treatment-naïve UC patients were also included into the analysis. UC-specific gene expression was interrogated in a subset of adjacent samples (5 C and 5 UC) using the Affymetrix GeneChip PrimeView Human Gene Expression Arrays. Only treatment-naïve UC separated from control. One-hundred-and-twenty genes with significant expression change in UC (> 2-fold, P < 0.05) were associated with differentially methylated regions (DMRs). Epigenetically associated gene expression changes (including gene expression changes in the IFITM1, ITGB2, S100A9, SLPI, SAA1, and STAT3 genes) were linked to colonic mucosal immune and defense responses. These findings underscore the relationship between epigenetic changes and inflammation in pediatric treatment-naïve UC and may have potential etiologic, diagnostic, and therapeutic relevance for IBD.     

Genetic Association of Peptidoglycan Recognition Protein Variants with Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is a common disease, includes Crohn''s disease (CD) and ulcerative colitis (UC), and is determined by altered gut bacterial populations and aberrant host immune response. Peptidoglycan recognition proteins (PGLYRP) are innate immunity bactericidal proteins expressed in the intestine. In mice, PGLYRPs modulate bacterial populations in the gut and sensitivity to experimentally induced UC. The role of PGLYRPs in humans with CD and/or UC has not been previously investigated. Here we tested the hypothesis that genetic variants in PGLYRP1, PGLYRP2, PGLYRP3 and PGLYRP4 genes associate with CD and/or UC and with gender and/or age of onset of disease in the patient population. We sequenced all PGLYRP exons in 372 CD patients, 77 UC patients, 265 population controls, 210 familial CD controls, and 24 familial UC controls, identified all polymorphisms in these populations, and analyzed the variants for significant association with CD and UC. We identified 16 polymorphisms in the four PGLYRP genes that significantly associated with CD, UC, and/or subgroups of patient populations. Of the 16, 5 significantly associated with both CD and UC, 6 with CD, and 5 with UC. 12 significant variants result in amino acid substitutions and based on structural modeling several of these missense variants may have structural and/or functional consequences for PGLYRP proteins. Our data demonstrate that genetic variants in PGLYRP genes associate with CD and UC and may provide a novel insight into the mechanism of pathogenesis of IBD.     

Characterization of Adherent Bacteroidales from Intestinal Biopsies of Children and Young Adults with Inflammatory Bowel Disease

There is extensive evidence implicating the intestinal microbiota in inflammatory bowel disease [IBD], but no microbial agent has been identified as a sole causative agent. Bacteroidales are numerically dominant intestinal organisms that associate with the mucosal surface and have properties that both positively and negatively affect the host. To determine precise numbers and species of Bacteroidales adherent to the mucosal surface in IBD patients, we performed a comprehensive culture based analysis of intestinal biopsies from pediatric Crohn''s disease [CD], ulcerative colitis [UC], and control subjects. We obtained biopsies from 94 patients and used multiplex PCR or 16S rDNA sequencing of Bacteroidales isolates for species identification. Eighteen different Bacteroidales species were identified in the study group, with up to ten different species per biopsy, a number higher than demonstrated using 16S rRNA gene sequencing methods. Species diversity was decreased in IBD compared to controls and with increasingly inflamed tissue. There were significant differences in predominant Bacteroidales species between biopsies from the three groups and from inflamed and uninflamed sites. Parabacteroides distasonis significantly decreased in inflamed tissue. All 373 Bacteroidales isolates collected in this study grew with mucin as the only utilizable carbon source suggesting this is a non-pathogenic feature of this bacterial order. Bacteroides fragilis isolates with the enterotoxin gene [bft], previously associated with flares of colitis, were not found more often at inflamed colonic sites or within IBD subjects. B. fragilis isolates with the ability to synthesize the immunomodulatory polysaccharide A [PSA], previously shown to be protective in murine models of colitis, were not detected more often from healthy versus inflamed tissue.     

DNA methylation-associated colonic mucosal immune and defense responses in treatment-naïve pediatric ulcerative colitis

Inflammatory bowel diseases (IBD) are emerging globally, indicating that environmental factors may be important in their pathogenesis. Colonic mucosal epigenetic changes, such as DNA methylation, can occur in response to the environment and have been implicated in IBD pathology. However, mucosal DNA methylation has not been examined in treatment-naïve patients. We studied DNA methylation in untreated, left sided colonic biopsy specimens using the Infinium HumanMethylation450 BeadChip array. We analyzed 22 control (C) patients, 15 untreated Crohn’s disease (CD) patients, and 9 untreated ulcerative colitis (UC) patients from two cohorts. Samples obtained at the time of clinical remission from two of the treatment-naïve UC patients were also included into the analysis. UC-specific gene expression was interrogated in a subset of adjacent samples (5 C and 5 UC) using the Affymetrix GeneChip PrimeView Human Gene Expression Arrays. Only treatment-naïve UC separated from control. One-hundred-and-twenty genes with significant expression change in UC (> 2-fold, P < 0.05) were associated with differentially methylated regions (DMRs). Epigenetically associated gene expression changes (including gene expression changes in the IFITM1, ITGB2, S100A9, SLPI, SAA1, and STAT3 genes) were linked to colonic mucosal immune and defense responses. These findings underscore the relationship between epigenetic changes and inflammation in pediatric treatment-naïve UC and may have potential etiologic, diagnostic, and therapeutic relevance for IBD.     

Molecular profiling of mucosal tissue associated microbiota in patients manifesting acute exacerbations and remission stage of ulcerative colitis

Dysbiosis of intestinal microflora has been postulated in ulcerative colitis (UC), which is characterized by imbalance of mucosal tissue associated bacterial communities. However, the specific changes in mucosal microflora during different stages of UC are still unknown. The aim of the current study was to investigate the changes in mucosal tissue associated microbiota during acute exacerbations and remission stages of UC. The mucosal microbiota associated with colon biopsy of 12 patients suffering from UC (exacerbated stage) and the follow-up samples from the same patients (remission stage) as well as non-IBD subjects was studied using 16S rRNA gene-based sequencing and quantitative PCR. The total bacterial count in patients suffering from exacerbated phase of UC was observed to be two fold lower compared to that of the non-IBD subjects (p?=?0.0049, Wilcox on matched-pairs signed rank tests). Bacterial genera including Stenotrophomonas, Parabacteroides, Elizabethkingia, Pseudomonas, Micrococcus, Ochrobactrum and Achromobacter were significantly higher in abundance during exacerbated phase of UC as compared to remission phase. The alterations in bacterial diversity with an increase in the abnormal microbial communities signify the extent of dysbiosis in mucosal microbiota in patients suffering from UC. Our study helps in identifying the specific genera dominating the microbiota during the disease and thus lays a basis for further investigation of the possible role of these bacteria in pathogenesis of UC.     

益生菌在炎症性肠病中的治疗作用

炎症性肠病(inflammatory bowel disease,IBD)包括溃疡性结肠炎(ulcerative colitis,UC)和克罗恩病(Crohn’s disease,CD)。随着对肠道微生物群在IBD发病机制中作用的认识不断深入,近年来益生菌广泛应用于IBD治疗。大量临床试验结果表明,益生菌治疗IBD的疗效主要体现在对UC和贮袋炎的治疗,对CD的疗效不明确。益生菌治疗IBD可能通过促进肠道微生物群平衡、改善肠道屏障功能、调节肠道黏膜免疫及营养物质代谢等途径。     

Identification of Environmental Factors Associated with Inflammatory Bowel Disease in a Southwestern Highland Region of China: A Nested Case-Control Study

BackgroundThe aim of this study was to examine environmental factors associated with inflammatory bowel disease (IBD) in Yunnan Province, a southwestern highland region of China.MethodsIn this nested case-control study, newly diagnosed ulcerative colitis (UC) cases in 2 cities in Yunnan Province and Crohn’s disease (CD) cases in 16 cities in Yunnan Province were recruited between 2008 and 2013. Controls were matched by geography, sex and age at a ratio of 1:4. Data were collected using the designed questionnaire. Conditional logistic regression models were used to estimate adjusted odds ratios (ORs).ResultsA total of 678 UC and 102 CD cases were recruited. For UC, various factors were associated with an increased risk of developing UC: dietary habits, including frequent irregular meal times; consumption of fried foods, salty foods and frozen dinners; childhood factors, including intestinal infectious diseases and frequent use of antibiotics; and other factors, such as mental labor, high work stress, use of non-aspirin non-steroidal anti-inflammatory drugs and allergies (OR > 1, p < 0.05). Other factors showed a protective effect: such as consumption of fruits, current smoking, physical activity, and drinking tea (OR < 1, p < 0.05). For CD, appendectomy and irregular meal times increased the disease risk (OR >1, p < 0.05), whereas physical activity may have reduced this risk (OR < 1, p < 0.05).ConclusionsThis study is the first nested case-control study to analyze the association between environmental factors and IBD onset in a southwestern highland region of China. Certain dietary habits, lifestyles, allergies and childhood factors may play important roles in IBD, particularly UC.     

Study of the therapeutic effect of raw and processed Vladimiriae Radix on ulcerative colitis based on intestinal flora,metabolomics and tissue distribution analysis

BackgroundThe intestinal flora imbalance and metabolic disorders are closely related to the pathogenesis of ulcerative colitis (UC). As a commonly used herb for the treatment of gastrointestinal diseases, Vladimiriae Radix (VR) has been used for hundreds of years, and its main active ingredients are costunolide (COS) and dehydrocostus lactone (DEH). Clinical usage habits and previous studies have shown that the processed Vladimiriae Radix (pVR) seems to be more suitable for treating bowel disease than the raw Vladimiriae Radix (rVR), but there is still no relevant comparative study.PurposeTo investigate the therapeutic effect of rVR and pVR on UC by analyzing the intestinal flora, metabolomics and tissue distribution.MethodsUC rat models were established to investigate the anti-inflammatory activities of rVR and pVR by enzyme-linked immunosorbent assay (ELISA), and to study their regulation of intestinal flora and metabolism by 16s rRNA gene analysis and Ultra Performance Liquid Chromatography Tandem Mass Spectrometry (UPLC-MS/MS). Moreover, the distribution of COS and DEH in UC mouse tissues were also observed by High Performance Liquid Chromatography Mass Spectrometry (HPLC-MS).ResultsrVR and pVR reduced tissue damage and the levels of TNF-α, IL-6, IL-1β, IL-10, TGF-β and MPO, especially pVR. 16s rRNA gene analysis showed that rVR superior in ameliorating species evenness and restoring the abundance of Lachnospiraceae and Ruminococcaceae, while pVR is better at increasing the richness and the abundance of Prevotellaceae. Metabolomics analysis suggested that rVR regulates the β-alanine, pantothenic acid and coenzyme A biosynthesis, but pVR regulates more abundant metabolic pathways. The tissue distribution data indicated the accumulation of COS and DEH in the gastrointestinal tract.ConclusionrVR and pVR had obvious therapeutic effect on UC. The potential mechanisms might be regulating abnormal metabolism, affecting the diversity and structure of intestinal flora, and accumulation of COS and DEH in colon.     

Effect of Alcoholic Intoxication on the Risk of Inflammatory Bowel Disease: A Nationwide Retrospective Cohort Study

PurposeThis study investigated whether alcoholic intoxication (AI) increases the risk of inflammatory bowel disease (IBD) by using a population-based database in Taiwan.MethodsThis retrospective matched-cohort study included 57 611 inpatients with new-onset AI (AI cohort) and 230 444 randomly selected controls (non-AI cohort). Each patient was monitored for 10 years to individually identify those who were subsequently diagnosed with Crohn disease (CD) and ulcerative colitis (UC) during the follow-up period. Cox proportional hazard regression analysis was conducted to determine the risk of IBD in patients with AI compared with controls without AI.ResultsThe incidence rate of IBD during the 10-year follow-up period was 2.69 per 1 000 person-years and 0.49 per 1 000 person-years in the AI and non-AI cohorts, respectively. After adjustment for age, sex, and comorbidity, the AI cohort exhibited a 3.17-fold increased risk of IBD compared with the non-AI cohort (hazard ratio [HR] = 3.17, 95% confidence interval [CI] = 2.19–4.58). Compared with the non-AI cohort, the HRs of CD and UC were 4.40 and 2.33 for the AI cohort, respectively. After stratification for the severity of AI according to the duration of hospital stay, the adjusted HRs exhibited a significant correlation with the severity; the HRs of IBD were 1.76, 6.83, and 19.9 for patients with mild, moderate, and severe AI, respectively (p for the trend < .0001).ConclusionThe risk of IBD was higher in patients with AI and increased with the length of hospital stay.