The genetics of inflammatory bowel disease

Eleven Grand Challenges for Inflammatory Bowel Disease Genetics and Genomics

The past 2 decades have witnessed extraordinary advances in our understanding of the genetic factors influencing inflammatory bowel disease (IBD), providing a foundation for the approaching era of genomic medicine. On behalf of the NIDDK IBD Genetics Consortium, we herein survey 11 grand challenges for the field as it embarks on the next 2 decades of research utilizing integrative genomic and systems biology approaches. These involve elucidation of the genetic architecture of IBD (how it compares across populations, the role of rare variants, and prospects of polygenic risk scores), in-depth cellular and molecular characterization (fine-mapping causal variants, cellular contributions to pathology, molecular pathways, interactions with environmental exposures, and advanced organoid models), and applications in personalized medicine (unmet medical needs, working toward molecular nosology, and precision therapeutics). We review recent advances in each of the 11 areas and pose challenges for the genetics and genomics communities of IBD researchers.

Inflammatory Gene Panel Guiding the Study of Genetics in Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is a complex disease that develops through a sequence of molecular events that are still poorly defined. This process is driven by a multitude of context-dependent genes that play different roles based on their environment. The complexity and multi-faceted nature of these genes make it difficult to study the genetic basis of IBD. The goal of this article is to review the key genes in the pathophysiology of IBD and highlight new technology that can be used in further research. This paper examines Nanostring RNA probe technology, which uses tissue analyzed without the use of enzymes, transcription, or amplification. Nanostring offers several panels of genes to test, including an inflammation panel of 234 genes. This article analyzes this panel and reviews the literature for each gene's effect in IBD for use as a framework to review the pathophysiology of the disease. The panel was narrowed to 26 genes with significant evidence of mechanistic potential in IBD, which were then categorized into specific areas of pathogenesis. These include gut barrier breakdown, inappropriate recognition of commensal bacteria, immune cell activation, proinflammatory cytokine release, and subsequent impairment of the anti-inflammatory response. The eventual goal of this paper is the creation of a customized panel of IBD genes that can be used to better understand the genetic mechanism of IBD and aid in the development of future therapies in IBD.

Multiomics-empowered Deep Phenotyping of Ulcerative Colitis Identifies Biomarker Signatures Reporting Functional Remission States

INTRODUCTION

Ulcerative colitis [UC] is a chronic disease with rising incidence and unclear aetiology. Deep molecular phenotyping by multiomics analyses may provide novel insights into disease processes and characteristic features of remission states.

METHODS

UC pathomechanisms were assessed by proteome profiling of human tissue specimens, obtained from five distinct colon locations for each of the 12 patients included in the study. Systemic disease-associated alterations were evaluated thanks to a cross-sectional setting of mass spectrometry-based multiomics analyses comprising proteins, metabolites, and eicosanoids of plasma obtained from UC patients during acute episodes and upon remission, in comparison with healthy controls.

RESULTS

Tissue proteome profiling indicated colitis-associated activation of neutrophils, macrophages, B and T cells, fibroblasts, endothelial cells and platelets, and hypoxic stress, and suggested a general downregulation of mitochondrial proteins accompanying the establishment of apparent wound healing-promoting activities including scar formation. Whereas pro-inflammatory proteins were apparently upregulated by immune cells, the colitis-associated epithelial cells, fibroblasts, endothelial cells, and platelets seemed to predominantly contribute anti-inflammatory and wound healing-promoting proteins. Blood plasma proteomics indicated chronic inflammation and platelet activation, whereas plasma metabolomics identified disease-associated deregulations of gut and gut microbiome-derived metabolites. Upon remission several, but not all, molecular candidate biomarker levels recovered back to normal.

CONCLUSION

The findings may indicate that microvascular damage and platelet deregulation hardly resolve upon remission, but apparently persist as disease-associated molecular signatures. This study presents local and systemic molecular alterations integrated in a model for UC pathomechanisms, potentially supporting the assessment of disease and remission states in UC patients.

Inflammatory bowel disease in families with four or more affected first-degree relatives

BACKGROUND

Family history increases the risk for inflammatory bowel diseases (IBDs). However, data on differences in phenotypic characteristics among patients with a strong family history of IBD are scarce and controversial. The aim of the study was to compare the phenotypic features of IBD patients with four or more affected first-degree relatives with sporadic cases of IBD.

METHODS

Patients with familial and sporadic IBD were identified from the institutional IBD database. IBD patients from families with at least four first-degree affected relatives were selected for analysis and were compared to non-matched sporadic cases with IBD chosen randomly. Comparison for type of IBD (Crohn's disease (CD) vs. ulcerative colitis (UC)), age at onset as well as for disease extent, behavior, extraintestinal manifestations and indicators of severe disease were analyzed.

RESULTS

Thirty-five patients with familial IBD (28 CD, seven UC) were compared to 88 sporadic IBD patients (61 CD, 24 UC and three IBDU). Disease duration was 10.3 ± 8.2 in the familial and 8.0 ± 7.2 years in the sporadic cases, p=.13. The familial cases were younger at diagnosis (19.3 ± 8.6 vs. 25.7 ± 11.8, p=.004). Patients with familial compared to sporadic IBD were significantly more likely to require steroid treatment (80% vs. 54.5%, p=.009), biological treatment (94.3%, vs. 63.6%, p<.001) or surgery (25.7%, vs. 11.4%, p=.048).

CONCLUSIONS

IBD with a very strong positive family history is associated with younger age at onset and a more adverse IBD phenotype compared to sporadic IBD.

Investigating the role of heat shock protein 47 in fibrosis in Crohn's disease

Crohn’s disease (CD) and ulcerative colitis (UC) are chronic inflammatory disorders of the gastrointestinal tract that share similar genetic risk factors. However, while fibrotic stricture of the intestine is a major characteristic of CD; it is rarely observed in UC. Deposition of collagen in the extracellular matrix contributes to the formation of fibrotic strictures in CD, but the underlying mechanisms are unknown. In the present study, we found that heat shock protein 47 (HSP47), a stress-response protein that acts as a molecular chaperone during the processing and secretion of collagen, expressed in the intestinal tissue from patients with CD. Serum HSP47 levels and anti-HSP47 antibody titers were significantly higher in patients with CD than in those with UC. Furthermore, anti-HSP47 antibody levels correlated significantly with fibrosis in CD. In addition, HSP47 inhibition significantly suppressed collagen production in fibroblasts in vitro. These findings suggest that HSP47 is a biomarker for differentiating fibrotic from non-fibrotic forms of CD. Additionally, we propose that HSP47 could be a potential target for treating fibrosis in patients with CD.

siRNA-based identification of IBD-related targets in human monocyte-derived dendritic cells

Inflammatory bowel disease (IBD) is thought to be caused by an aberrant host response to the commensal enteric flora in genetically susceptible individuals. Dendritic cells (DCs) play a key role in the regulation of this response as they sample gut commensals. In healthy individuals DCs actively contribute to tolerance upon recognition of these resident bacteria, whereas in individuals with IBD, DCs will initiate an inflammatory response. To mimic the disease response in vitro, human monocyte-derived DCs were matured with E. coli causing the cells to produce high levels of the pro-inflammatory cytokine IL-12/IL-23p40 (p40) and low levels of the anti-inflammatory cytokine IL-10. A siRNA-based screening assay was developed and screened to identify potential therapeutic targets that shift this balance towards an immunosuppressive state with lower levels of p40 and higher levels of IL-10. The screening assay was optimized and quality controlled using non-targeting controls and positive control siRNAs targeting IL12B and TLR4 transcripts. In the primary screen, smartpool siRNAs were screened for reduction in p40 expression, induction of IL-10 levels, or increase in IL-10:p40 ratios without affecting cell viability. All potential targets were taken forward into a confirmation screen in a different DC donor in which four individual siRNAs per target were screened. At least two siRNAs per target should have an effect to be considered a valid target. This screen resulted in a concise list of ten genes, of which their role in DC maturation is currently being investigated.

Incidence trends of pediatric onset inflammatory bowel disease in the years 2000-2009 in Saxony, Germany-first results of the Saxon Pediatric IBD Registry

Aims

In developed countries, the incidence of inflammatory bowel disease (IBD) such as Crohn's disease (CD) and ulcerative colitis (UC) is increasing. Therefore, we aimed to investigate the incidence rates and trends over time in the population of children and adolescents in one of the federal states of Germany, in Saxony.

Methods

Over the 10-year period 2000–2009 all 31 children’s hospitals and pediatric gastroenterologists, respectively in Saxony reported all IBD patients up to 15 years of age to the Saxon Pediatric IBD Registry. The completeness of the registry was estimated as 96.7% by independent surveys in the years 2005–2009. Incidence rates were presented as age-standardized incidence rates (ASR) regarding New European Standard Population 1990 per 100,000 person-years (PY) with 95% confidence intervals [CI]. Joinpoint and linear regression was used for trend analyses.

Results

344 patients with confirmed IBD between 2000–2009 were included in the epidemiological evaluation: 212 (61.6%) patients with CD, 122 (35.6%) with UC and 10 (2.9%) with unclassified IBD (IBD-U). The ASR per 100,000 PY over the whole observation period was 7.2 [6.4–7.9] for IBD, 4.4 [3.8–5.0] for CD, 2.6 [2.1–3.0] for UC and 0.2 [0.1–0.3] for IBD-U. For IBD, the ASR per 100,000 PY increased from 4.6 [2.8–6.3] in 2000 to 10.5 [7.5–13.6] in 2009. The incidence trend analysis of ASRs using the joinpoint regression confirmed a significant increase of IBD as well as UC. The mean age at first diagnosis decreased significantly during the observation period from 11.5 (11.0–13.4) in 2000 to 9.6 (5.1–13.5) years in 2009. The median of the diagnostic latency among IBD patients was 3 months.

Conclusion

The incidence of IBD in children and adolescents in Saxony was slightly higher than the average of other countries in the same time period and followed the trend towards a general increase of IBD. The age at diagnosis was subject to a very unfavorable downward trend.

From genes polymorphisms to mucosal expression of cytokines: evaluating IL-23/IL-17 axis in adult patients with gastritis

Background and Objective

Chronic inflammation is the typical sign of gastritis that may shift into gastric cancer. IL-17A and IL-17F as a novel inflammatory cytokines subset of CD4+Th play the main role in inflammation. A key cytokine receptor in the inflammatory IL-17/IL-23 axis, the interleukin 23 receptor (IL23R), may be related to gastritis. We evaluated the correspondence between IL-17A G197A, IL-17F A7488G and IL23R+2199 A/C polymorphisms with TGF-β1, IL-6, IL-17, IL-21 and IL-23 mucosal mRNAs expression in uninfected H. Pylori (HP) chronic gastritis patients.

Materials and Methods

Total RNA and genomic DNA were separated from gastric biopsies of 44 patients with gastritis. Subsequently, mucosal mRNAs expression of TGF-β1, IL-6, IL-17, IL-21 and IL-23 were assessed by real-time PCR. To polymorphisms determination of IL-17A G197A, IL-17F A7488G and IL-23R +2199A/C the PCR-RFLP was used in gastric biopsies.

Results

Results point that IL-17A G197A, IL-17F A7488G and IL23R +2199A/C polymorphisms did not influence the mucosal expression of TGF-β1, IL-6, IL-17 and IL-21 (p> 0.05). In an opposite result, we don't find a correspondence between IL-17A G197A, IL-17F A7488G polymorphisms and mucosal expression of IL-23 (p> 0.05). In a contrary, we found a correlation between IL23R +2199A/C polymorphism and mucosal expression of IL-23 in patients with chronic gastritis (p< 0.05).

Conclusion

These findings propose that IL23R +2199A/C polymorphism may change the mucosal expression of IL-23 pattern in patients with gastritis disease in the absence of HP, but to support the conclusion, more research may be required.

Association between Inflammatory Bowel Disease and Pancreatitis: A PRISMA-Compliant Systematic Review

METHODS

MEDLINE, Embase, and CENTRAL were systematically searched for correlative studies till 2 November 2019. RevMan5.3 was used to estimate relevance.

RESULTS

Three studies with 166008 participants were included. The risk of pancreatitis significantly increased in the patients with CD (OR, 3.40; 95% CI, 2.70-4.28; P < 0.00001) and UC (OR, 2.49; 95% CI, 1.91-3.26; P < 0.00001). Increased risks of CD (OR, 12.90; 95% CI, 5.15-32.50; P < 0.00001) and UC (OR, 2.80; 95% CI, 1.00-7.86; P = 0.05) were found in patients with chronic pancreatitis. As for patients with acute pancreatitis, there were significant association of CD (OR, 3.70; 95% CI, 1.90-7.60; P = 0.0002), but were not UC.

CONCLUSIONS

The evidence confirmed an association between pancreatitis and IBD. When pancreatitis patients have chronic diarrhea and mucus blood stool or IBD patients have repeated abdominal pain and weight loss, they should consult pancreatic and gastrointestinal specialists.

Identification of 3',4',5'-trihydroxyflavone as an mammalian target of rapamycin inhibitor and its suppressive effects on dextran sulfate sodium-induced ulcerative colitis

Flavone derivatives have been shown to possess anti-inflammatory properties in various inflammation model systems; however, their underlying molecular mechanisms remain elusive. In this study, a flavone derivative 3',4',5'-trihydroxyflavone (THF; NJK16003) was synthesized, and its anti-inflammatory effects and molecular targets were investigated using in vitro systems and an in vivo colitis model. NJK16003 showed potent anti-inflammatory activities in cell-based assays using macrophages. In vitro enzyme activity assays using various inflammation-related kinases revealed the mammalian target of rapamycin (mTOR) as a possible molecular target. Treatment of RAW264.7 cells with NJK16003 resulted in an increase in light chain 3B protein lipidation and a decrease in p62 protein levels and ribosomal S6 kinase phosphorylation, indicating that NJK16003 induces autophagy through mTOR inhibition. NJK16003 treatment resulted in significant induction of autophagy and suppression of inflammatory responses in intestinal epithelial cells. Autophagy induction has been shown to alleviate colitis by suppressing inflammatory responses and apoptotic cell death of intestinal epithelial cells. Indeed, inflammatory responses and intestinal epithelial cell death in our DSS-induced colitis mouse model were significantly suppressed by NJK16003 treatment. Our results indicate that NJK16003 could suppress inflammation by inducing autophagy through its mTOR inhibitory activity. These results suggest that NJK16003 could be a possible therapeutic agent for the treatment of inflammatory bowel diseases including colitis.

Association Between Cannabis Use and Complications Related to Crohn's Disease: A Retrospective Cohort Study

BACKGROUND

Crohn's disease is an idiopathic inflammatory process that is occasionally associated with complications, which cause significant morbidity and mortality. The anti-inflammatory effect of cannabis in intestinal inflammation has been shown in several experimental models; it is unknown whether this correlates with fewer complications in Crohn's disease patients.

AIMS

To compare the prevalence of Crohn's disease-related complications among cannabis users and non-users in patients admitted with a primary diagnosis of Crohn's disease or a primary diagnosis of Crohn's related complication and a secondary diagnosis of Crohn's disease between 2012 and 2014.

METHODS

We used data from the Healthcare Cost and Utilization Project-National Inpatient Sample. Cannabis users (615) were compared directly after propensity score match to non-users, in aspects of various complications and clinical end-points.

RESULTS

Among matched cohorts, Cannabis users were less likely to have the following: active fistulizing disease and intra-abdominal abscess (11.5% vs. 15.9%; aOR 0.68 [0.49 to 0.94], p = 0.025), blood product transfusion (5.0% vs. 8.0%; aOR 0.48 [0.30 to 0.79], p = 0.037), colectomy (3.7% vs. 7.5%; aOR 0.48 [0.29-0.80], p = 0.004), and parenteral nutrition requirement (3.4% vs. 6.7%, aOR 0.39 [0.23 to 0.68], p = 0.009).

CONCLUSION

Cannabis use may mitigate several of the well-described complications of Crohn's disease among hospital inpatients. These effects could possibly be through the effect of cannabis in the endocannabinoid system.

Association of Psoriasis With Inflammatory Bowel Disease: A Systematic Review and Meta-analysis

Importance

Patients with psoriasis may experience comorbidities involving cardiovascular diseases, chronic kidney disease, uveitis, psychiatric disturbances, and metabolic syndrome. However, the association between psoriasis and inflammatory bowel disease (IBD) has been largely unclear.

Objective

To investigate the association of psoriasis with IBD.

Data Sources

For this systematic review and meta-analysis, MEDLINE, Embase, and the Cochrane Central Register of Controlled Trials were searched for relevant studies from inception to January 17, 2018.

Study Selection

Case-control, cross-sectional, or cohort studies that examined either the odds or risk of IBD in patients with psoriasis were included. No geographic or language limitations were used in the search.

Data Extraction and Synthesis

The PRISMA and MOOSE guidelines were followed for data extraction. The Newcastle-Ottawa Scale was used to evaluate the risk of bias of included studies. Crohn disease and ulcerative colitis were analyzed separately and random-effects model meta-analysis was conducted. A subgroup analysis was performed on psoriatic arthritis.

Main Outcomes and Measures

The risk and odds of IBD, Crohn disease, and ulcerative colitis in patients with psoriasis.

Results

A total of 5 case-control or cross-sectional studies and 4 cohort studies with 7 794 087 study participants were included. Significant associations were found between psoriasis and Crohn disease (odds ratio, 1.70; 95% CI, 1.20-2.40) and between psoriasis and ulcerative colitis (odds ratio, 1.75; 95% CI, 1.49-2.05). Patients with psoriasis had an increased risk of Crohn disease (risk ratio, 2.53; 95% CI, 1.65-3.89) and ulcerative colitis (risk ratio, 1.71; 95% CI, 1.55-1.89).

Conclusions and Relevance

These findings suggest that psoriasis is significantly associated with IBD. Gastroenterology consultation may be indicated when patients with psoriasis present with bowel symptoms.

Cross-Talk Between Antigen Presenting Cells and T Cells Impacts Intestinal Homeostasis, Bacterial Infections, and Tumorigenesis

Innate immunity is maintained in part by antigen presenting cells (APCs) including dendritic cells, macrophages, and B cells. APCs interact with T cells to link innate and adaptive immune responses. By displaying bacterial and tumorigenic antigens on their surface via major histocompatibility complexes, APCs can directly influence the differentiation of T cells. Likewise, T cell activation, differentiation, and effector functions are modulated by APCs utilizing multiple mechanisms. The objective of this review is to describe how APCs interact with and influence the activation of T cells to maintain innate immunity during exposure to microbial infection and malignant cells. How bacteria and cancer cells take advantage of some of these interactions for their own benefit will also be discussed. While this review will cover a broad range of topics, a general focus will be held around pathogens, cancers, and interactions that typically occur within the gastrointestinal tract.

Epigenetics, DNA Organization, and Inflammatory Bowel Disease

Inflammatory bowel diseases (IBDs) are chronic inflammatory disorders affecting the gastrointestinal tract. The incidence of IBD is increasing, with more cases occurring in developed countries. Multiple factors such as genetics, environmental changes, gut microbiota, and immune abnormalities have been associated with development of IBD. In recent years, it has become increasingly apparent that epigenetic modifications of chromatin and the manner in which chromatin is organized in the nucleus are additionally important elements that can influence responses induced by the factors described above, and may therefore contribute to the onset and pathogenesis of IBD. Epigenetics and chromatin organization regulate diverse functions that include maintenance of homeostasis in the intestinal epithelium, the development and differentiation of immune cells, and modulation of responses generated by the immune system to defend against potential pathogens. Furthermore, changes in epigenetic chromatin marks and in chromatin organization have now been linked to differential gene expression in IBD patient cells. Although direct evidence for a role of histone modifications in IBD is currently very limited, in this review, we summarize the links between various epigenetic modifications, the proteins that catalyze or recognize these modifications, and the development or progression of IBD in human and experimental IBD. We also discuss how epigenetics influence the organization of DNA contacts to regulate gene expression and the implications this may have for diagnosing and treating IBD.

Host immunoglobulin G selectively identifies pathobionts in pediatric inflammatory bowel diseases

BACKGROUND

Inflammatory bowel diseases (IBD) are a group of complex and multifactorial disorders with unknown etiology. Chronic intestinal inflammation develops against resident intestinal bacteria in genetically susceptible hosts. We hypothesized that host intestinal immunoglobulin (Ig) G can be used to identify bacteria involved in IBD pathogenesis.

RESULTS

IgG-bound and -unbound microorganisms were collected from 32 pediatric terminal ileum aspirate washes during colonoscopy [non-IBD (n = 10), Crohn disease (n = 15), and ulcerative colitis (n = 7)], and composition was assessed using the Illumina MiSeq platform. In vitro analysis of invasive capacity was evaluated by fluorescence in situ hybridization and gentamicin invasion assay; immune activation was measured by qPCR. Despite considerable inter-individual variations, IgG binding favored specific and unique mucosa-associated species in pediatric IBD patients. Burkholderia cepacia, Flavonifractor plautii, and Rumminococcus sp. demonstrated increased IgG binding, while Pseudomonas ST29 demonstrated reduced IgG binding, in IBD. In vitro validation confirmed that B. cepacia, F. plautii, and Rumminococcus display invasive potential while Pseudomonas protogens did not.

CONCLUSION

Using IgG as a marker of pathobionts in larger patient cohorts to identify microbes and elucidate their role in IBD pathogenesis will potentially underpin new strategies to facilitate development of novel, targeted diagnostic, and therapeutic approaches. Interestingly, this method can be used beyond the scope of this manuscript to evaluate altered gut pathobionts in a number of diseases associated with altered microbiota including arthritis, obesity, diabetes mellitus, alcoholic liver disease, cirrhosis, metabolic syndrome, and carcinomas.

Overview of Link Between Inflammatory Bowel Disease and Cardiovascular Disease

Inflammation has been shown to play an increasingly important role in the pathogenesis of atherosclerosis and in precipitating thrombotic events. Inflammatory bowel disease (IBD) is a systemic inflammatory disorder with a wide range of extraintestinal manifestations including a clinically significant increase in the risk of venous thromboembolism compared to matched controls in several studies. The data for the association between IBD and ischemic heart disease are less clear; multiple population-based studies have shown both positive and negative associations between the 2 conditions. While the systemic inflammation should theoretically increase the risk for cardiovascular disease, inflammatory bowel also potentially provides a cardioprotective effect in several ways. Patients with IBD typically enter the healthcare system at an earlier age and experience a lower incidence of obesity, hypercholesterolemia, and hyperlipidemia. Given the complex interplay among the proatherogenic, prothrombogenic, and cardioprotective effects, IBD should be taken into consideration as a nontraditional risk factor for cardiovascular disease in specific subsets of patients.

Differences in Clinical Course, Genetics, and the Microbiome Between Familial and Sporadic Inflammatory Bowel Diseases

BACKGROUND AND AIM

Family history is the strongest risk factor for developing Crohn's disease [CD] or ulcerative colitis [UC]. We investigated whether the proximity of relationship with the affected relative and concordance for type of inflammatory bowel disease [IBD] modifies the effect of family history on phenotype and disease severity.

METHOD

This cross-sectional study included patients with a confirmed diagnosis of IBD in a clinical registry. Family history of IBD was assessed by a questionnaire ascertaining presence of disease in a first-first-degree, second-second-degree or distant relative. Our primary outcomes were disease phenotype as per the Montreal classification and severity measured by need for immunomodulator, biologic, or surgical therapy. Genotyping was performed on the Immunochip and faecal samples were subjected to 16S rRNA microbiome sequencing.

RESULTS

Our study included 2136 patients with IBD [1197 CD, 939 UC]. Just under one-third [32%] of cases ere familial IBD [17% first-degree, 21% second-degree]. Familial IBD was diagnosed at an earlier age, both in CD [26 vs 28 years, p = 0.0006] and UC [29 vs 32 years, p = 0.01]. Among CD patients, a positive family history for CD was associated with an increased risk for complicated disease in the presence of an affected family member (odds ratio [OR] 1.48, 95% confidence interval [CI] 1.07-2.03). However, this effect was significant only for first-degree relatives [OR 1.82, 95% CI 1.19-2.78].

CONCLUSIONS

A family history of CD in first-degree relatives was associated with complicated CD. Family history discordant for type of IBD or in distant relatives did not influence disease phenotype or natural history.

MYO9B gene polymorphisms are associated with the risk of inflammatory bowel diseases

Myosin IXB (MYO9B) gene polymorphisms have been extensively investigated in terms of their associations with inflammatory bowel disease (IBD), with contradictory results. The aim of this meta-analysis was to evaluate associations between MY09B gene polymorphisms and the risk of IBD, Crohn's disease (CD) and ulcerative colitis (UC). Eligible studies from PubMed, Embase, and CNKI databases were identified. Pooled odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated. Ten studies published in eight papers reporting 8,975 cases and 9,482 controls were included in this meta-analysis. Five MY09B gene polymorphisms were evaluated: rs1545620, rs962917, rs1457092, rs2305764, and rs2305767. Our data suggested that the rs1545620 polymorphism was associated with a decreased risk of IBD. A similar result was found for rs2305767 and UC. The rs962917 single nucleotide polymorphism (SNP) increased the risk of IBD, CD and UC. Moreover, rs1457092 increased the risk of IBD and UC. Rs2305764 was also associated with an increased risk of IBD. Furthermore, stratification analyses indicated that rs1545620 decreased the risk of IBD, while rs962917 increased the risk of IBD, CD and UC in Caucasian populations. To sum up, our data indicate that these five SNPs in MY09B are significantly associated with the risk of IBD.

An Update on Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) includes 2 chronic idiopathic inflammatory diseases: ulcerative colitis and Crohn disease. The incidence and prevalence of IBD is increasing worldwide. It can affect people of all ages, including children and geriatric populations, and can impact all aspects of life. In this article, diagnosis and treatment of IBD in adults, pediatric, pregnant, and elderly populations are explored from the perspective of a primary care physician.

Targeted Metagenome Based Analyses Show Gut Microbial Diversity of Inflammatory Bowel Disease patients

Inflammatory bowel disease (IBD) is a multifactorial disease including both genetic and environmental factors. We compared the diversity of intestinal microbesamong a cohort of IBD patients to study the microbial ecological effects on IBD. Fecal samples from patients were sequenced with next generation sequence technology at 16S rDNA region. With statistical tools, microbial community was investigated at different level. The gut microbial diversity of Crohn's disease (CD) patients and colonic polyp (CP) patients significantly different from each other. However, the character of ulcerative colitis (UC) patients has of both CD and CP features. The microbial community from IBD patients can be very different (CD patient) or somewhat similar (UC patients) to non-IBD patients. Microbial diversity can be an important etiological factor for IBD clinical phenotype.

Orofacial Crohn’s disease: A case report

Background: Crohn’s disease (CD) and ulcerative colitis (UC) are the two major relapsing conditions of inflammatory bowel diseases. Case Report: A case of Crohn’s disease with orofacial manifestations in a 10 year old girl is described. She had suffered from fever, dysphagia, arthralgia, painful recurrent ulcers of the oral mucosa and swelling of the lower lip lasting over 6 weeks. Clinical examination and the punch biopsy from the buccal mucosa revealed major recurrent aphthous ulcerations. A partial regression and significant relief of lesions were achieved two weeks after the treatment, but the patient suffered from abdominal pain, irregular bowel movements, arthritis, multiple hyperplastic and swollen mucosal folds, after 3 months. The patient was referred to a pediatric gastroenterologist. Esophagogastroduodenoscopy showed pyloric ulcer formation. Abdominal ultrasound showed increased thickening of the ileal wall with multiple enlarged lympadenopathies in the periileal region. Colonoscopy images showed deep ulcers with surrounding erythema. The histopathological examination of biopsies from the terminal ileum and the colon showed basal plasmacytosis, minimal crypt distortions and aphthous ulcerations. The diagnosis of Orofacial Crohn’s disease was made. Exclusive enteral nutrition for 8 weeks, followed by azathiopurine treatment was started with an excellent clinical response on abdominal and oral symptoms. Conclusion: Diagnosis of the disease by dentists and other clinicians through the evaluation of oral clinical findings is very rare. Mucocutaneous and granulomatous lesions of the oral cavity should alert the clinician to pursue an underlying systemic cause. Early communication with a gastroenterologist can help early diagnosis of Crohn’s disease for better patient management and prognosis.

Deoxyschizandrin suppresses dss-induced ulcerative colitis in mice

BACKGROUND/AIMS

Deoxyschizandrin as one of the most important component of Schisandra chinensis (Turcz.) Baill plays an immunomodulatory role in a variety of diseases, yet its role in ulcerative colitis remains to be elucidated. We aimed to investigate the role of deoxyschizandrin in DSS-induced ulcerative colitis in mice.

PATIENTS AND METHODS

In the present study, an inflammation model of cells was constructed to confirm the anti-inflammatory effect of deoxyschizandrin. Then a mouse model with Dextran sulfate sodium sulfate (DSS)-induced ulcerative colitis was constructed, and the effects of deoxyschizandrin on mouse colon inflammation, apoptosis, and CD4 T lymphocyte infiltration in ulcerative colitis were examined.

RESULT

Deoxyschizandrin could improve the symptoms of ulcerative colitis, determined by hematoxylin-eosin (HE) staining and histopathological scores. Moreover, deoxyschizandrin reduced the levels of inflammatory cytokines, suppressed CD4 T cell infiltration, and effectively inhibited apoptosis in the colon of DSS-induced ulcerative colitis mice.

CONCLUSION

In summary, deoxyschizandrin can effectively rescue the symptoms of DSS-induced ulcerative colitis in mice by inhibiting inflammation. T cell infiltration and apoptosis in the colon, suggesting that deoxyschizandrin could be a potential drug in treating ulcerative colitis.

A long noncoding RNA signature for ulcerative colitis identifies IFNG-AS1 as an enhancer of inflammation

High-throughput technologies revealed new categories of genes, including the long noncoding RNAs (lncRNAs), involved in the pathogenesis of human disease; however, the role of lncRNAs in the ulcerative colitis (UC) has not been evaluated. Gene expression profiling was used to develop lncRNA signatures in UC samples. Jurkat T cells were activated by PMA/ionomycin subsequently interferon-γ (IFNG) and tumor necrosis factor (TNF)-α protein levels were assessed by ELISA. Anti-sense molecules were designed to block IFNG-AS1 expression. A unique set of lncRNAs was differentially expressed between UC and control samples. Of these, IFNG-AS1 was among the highest statistically significant lncRNAs (fold change: 5.27, P value: 7.07E-06). Bioinformatic analysis showed that IFNG-AS1 was associated with the IBD susceptibility loci SNP rs7134599 and its genomic location is adjacent to the inflammatory cytokine IFNG. In mouse models of colitis, active colitis samples had increased colonic expression of this lncRNA. Utilizing the Jurkat T cell model, we found IFNG-AS1 to positively regulate IFNG expression. Novel lncRNA signatures differentiate UC patients with active disease, patients in remission, and control subjects. A subset of these lncRNAs was found to be associated with the clinically validated IBD susceptibility loci. IFNG-AS1 was one of these differentially expressed lncRNAs in UC patients and found to regulate the key inflammatory cytokine, IFNG, in CD4 T cells. Taking these findings together, our study revealed novel lncRNA signatures deregulated in UC and identified IFNG-AS1 as a novel regulator of IFNG inflammatory responses, suggesting the potential importance of noncoding RNA mechanisms on regulation of inflammatory bowel disease-related inflammatory responses.

The IL-17-Th1/Th17 pathway: an attractive target for lung cancer therapy?

INTRODUCTION

There is strong pharmaceutical development of agents targeting the IL-17-TH17 pathway for the treatment of psoriasis (Ps) and psoriatic arthritis (PsA). Lung cancer accounts for 28% of all cancer-related deaths worldwide, and roughly 80% of patients with newly-diagnosed non-small cell lung cancer (NSCLC) present with metastatic disease, with a poor prognosis of around 12 months. Therefore, there is a high unmet medical need for the development of new and potent systemic treatments in this deadly disease. The emergence of immunotherapies such as anti-PD-1 or anti-PDL1 as candidate therapies in non-small cell lung cancer (NSCLC) indicates that targeting critical immuno-modulatory cytokines including those within the IL-17-Th1/Th17 axis may have proven benefit in the treatment of lung cancer. Areas covered: In this review we describe the current evidence for aberrant IL-17-Th1/Th17 settings in cancer, particularly with regard to targeting this axis in NSCLC. We further discuss the current agents under pharmaceutical development which could potentially target this axis, and discuss the current limitations and areas of concern regarding the use of these in lung cancer. Expert opinion: Current evidence suggests that moving forward agents targeting the IL-17-Th1/Th17 pathway may have novel new oncoimmunology indications in the treatment paradigm for NSCLC.

Autoinflammatory granulomatous diseases: from Blau syndrome and early-onset sarcoidosis to NOD2-mediated disease and Crohn's disease

The recent identification of genetic mutations leading to dysfunction of inflammatory and apoptotic pathways, has allowed to characterise a group of diseases, recognised as monogenic autoinflammatory syndromes. Among those, Blau syndrome (BS) and early-onset sarcoidosis (EOS) have been identified as familial and sporadic phenotypes of the same non-caseating granulomatous form. Both the diseases are caused by mutations in the CARD15/NOD2 gene, encoding the cytosolic NOD2 protein, one of the key molecules in the regulation of innate immunity. Clinical onset is typically located in the first years of life and phenotype is characterised by simultaneous or less articular, cutaneous and ocular non-caseating granulomatous inflammation, which can be variably associated with a heterogeneous systemic spectrum. The CARD15/NOD2 gene has also been identified as one of the genes linked to susceptibility to Crohn's disease (CD), a common polygenic inflammatory granulomatous bowel disease. The heightened nuclear factor-κB activity, found in the intestinal tissue of patients affected by CD, has probably a genetic cause related to several CARD15/NOD2 polymorphisms. Other substitutions in the CARD15/NOD2 gene have also been found in a recently described disorder, called NOD2-associated autoinflammatory disease, which shares several clinical characteristics with BS and EOS. This review attempts to describe these diseases on the basis of the most recent evidences. We described genetic and clinical aspects, mainly focusing on BS and EOS, the most representative diseases of autoinflammatory granulomatous diseases, with the ultimate purpose to expand their knowledge.

Oral Manifestations of Crohn's Disease: A Case Report and Review of the Literature

Crohn's disease (CD) is an inflammatory disorder of the gastrointestinal tract that is likely caused by an inappropriate mucosal inflammatory response to intestinal bacteria in a genetically predisposed host. The lesions of CD can involve any region of the GI tract as well as extraintestinal sites such as the skin, joints, and eyes. The most common presenting symptoms are abdominal pain and prolonged diarrhea associated with fevers, fatigue, and malaise. Delayed growth and failure to thrive may also be observed in pediatric patients. Oral manifestations of CD are known as oral CD and may precede GI involvement, thus serving as early markers of this condition. We describe a 6-year-old male who presented with oral lesions as his initial manifestation of disease and review the current literature pertaining to oral CD.

Intestinal Antigen-Presenting Cells: Key Regulators of Immune Homeostasis and Inflammation

The microbiota that populate the mammalian intestine are critical for proper host physiology, yet simultaneously pose a potential danger. Intestinal antigen-presenting cells, namely macrophages and dendritic cells (DCs), are integral components of the mucosal innate immune system that maintain co-existence with the microbiota in face of this constant threat. Intestinal macrophages and DCs integrate signals from the microenvironment to orchestrate innate and adaptive immune responses that ultimately lead to durable tolerance of the microbiota. Tolerance is not a default response, however, because macrophages and DCs remain poised to vigorously respond to pathogens that breach the epithelial barrier. In this review, we summarize the salient features of macrophages and DCs in the healthy and inflamed intestine and discuss how signals from the microbiota can influence their function.

Increased risk of varicella zoster virus infection in inflammatory bowel disease in an Asian population: a nationwide population-based cohort study

PURPOSE

Whether patients with inflammatory bowel disease (IBD) exhibit a high risk of developing varicella zoster virus (VZV) infection in Asian populations remains inconclusive. We investigated the causal relationship between two diseases by analysing the Taiwan National Health Insurance Research Database.

PATIENTS AND METHODS

Based on a universal insurance claims database, we enrolled 7055 IBD patients and 28,220 age- and sex-matched controls. We calculated the hazard ratios (HRs) and 95% confidence intervals (CIs) of the herpes zoster virus (HZV) in the IBD and comparison cohorts, using the Cox proportional hazards regression model.

RESULTS

Patients with IBD exhibited significantly higher risk of the HZV compared with the controls (adjusted HRs, 1.42; 95% CI, 1.27-1.60). Further analysis indicated that male patients (adjusted HRs, 1.61; 95% CI, 1.35-1.92), aged 35-44 (adjusted HRs, 1.47; 95% CI, 1.08-2.01) and aged 65 years and older (adjusted HRs, 1.47; 95% CI, 1.19-1.80), and patients without comorbidities (adjusted HRs, 1.44; 95% CI, 1.26-1.66), exhibited excessive risks of VZV infection. Moreover, our findings show that the overall risk of developing VZV infection increased risk from 1.03 (95% CI, 0.90-1.18) (≤ 2 visits) to 9.76 (95% CI, 7.60-12.5) (> 4 visits), which correlates positively with the frequency of medical visits (trend test p < 0.0001).

CONCLUSION

Patients with IBD, particularly men aged 35-44/65 years and over, and patients without comorbidities, are associated with a long-term risk of VZV infection. The excessive risk of VZV infection should be considered for administering vaccines to IBD patients.

Associations between STAT3 rs744166 polymorphisms and susceptibility to ulcerative colitis and Crohn's disease: a meta-analysis

BACKGROUND

Many studies have investigated the associations between the signal transducer and activator of transcription 3 (STAT3) in the susceptibility to ulcerative colitis (UC) and Crohn's disease (CD). However, the results remain inconsistent. This meta-analysis determined the risk of STAT3 rs744166 polymorphism-conferred UC and CD susceptibility.

MATERIALS AND METHODS

Electronic databases, including PubMed, EMBASE and the Cochrane Library, were searched for all eligible studies that evaluated the association between STAT3 rs744166 polymorphisms with UC and CD risk up to August 21, 2014. The pooled odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated using fixed- or random-effects models.

RESULTS

Twelve studies containing 10298 patients with CD, 4244 patients with UC and 11191 controls were included in this meta-analysis. The results indicated that the STAT3 rs744166 polymorphism was associated with CD and UC susceptibility (CD: GA+AA vs. GG, OR = 1.20, 95%CI, 1.11-1.30, I2 = 0%, Punadjusted<0.00001, PBonferroni<0.00005, PFDR<0.00001; UC: GA+AA vs. GG, OR = 1.21, 95%CI, 1.08-1.36, I2 = 1%, Punadjusted = 0.001, PBonferroni = 0.005, PFDR = 0.00125). In subgroup analyses by ethnicity, the significant association was found only among Caucasians. However, when grouped by age of onset, positive associations were found both among adults and children. In addition, when stratified by study design and genotyping methods, the risk of CD was significantly associated with the STAT3 rs744166 polymorphism in hospital-based and population-based groups and in SNP Array and SNPlex groups. For UC, significant associations were also found in population-based, PCR-RFLP and SNPlex groups. Moreover, these findings were sufficiently robust to withstand the Bonferroni correction and false discovery rate (FDR).

CONCLUSION

This meta-analysis indicates that carriers of the STAT3 rs744166 'A' allele have a significantly greater risk of CD and UC, especially among Caucasians.

Dietary clues to the pathogenesis of Crohn's disease

Crohn's disease is a complex inherited disorder of unknown pathogenesis with environmental, genetic and microbial factors involved in the development of the disease. A remarkable feature of this disease in childhood is the effective response to exclusive enteral nutrition (EEN) therapy and the need for complete exclusion of normal diet required for success (principle of exclusivity). EEN or dietary interventions might act through removal of dietary components, which affect microbial composition, decrease a proinflammatory response and promote restitution of the epithelial barrier, likewise allowing termination of this vicious disease-forming cycle before a critical threshold is reached. Multiple traditional and nontraditional dietary components may affect the microbiome, mucous layer, intestinal permeability, or adherence and translocation of pathobionts. We review the epidemiological data, as well as data from animal models and cell lines, and propose a model for pathogenesis we have termed the 'bacterial penetration cycle', whereby dietary components such as animal fat, high sugar intake and gliadin, and consumption of emulsifiers, maltodextrin as well as low-fiber diets may be able to cause a localized acquired bacterial clearance defect, leading to bacterial adhesion and penetration, and subsequently inflammation in the gut.

Functional polymorphisms in interleukin-23 receptor and susceptibility to esophageal squamous cell carcinoma in Chinese population

BACKGROUND

As a key element in the T-helper 17 (Th17) cell-mediated inflammatory process, interleukin-23 receptor (IL-23R) plays a crucial role in the pathogenesis of cancer. Single nucleotide polymorphisms (SNPs) in IL-23R have been frequently studied in several previous case-control cancer studies, but its association with esophageal squamous cell carcinoma (ESCC) in Chinese population has not been investigated. This study examined whether genetic polymorphisms in IL-23R were associated with ESCC susceptibility.

METHODS

A hospital-based case-control study of 684 ESCC patients and 1064 healthy controls was performed to assess the association between four previous reported IL-23R genotypes (rs6682925, rs6683039, rs1884444 and rs10889677) and ESCC risk. The results revealed that the C allele of the rs10889677A>C polymorphism in the 3'UTR of IL-23R gene was inversely associated with the risk of ESCC.

RESULTS

The rs10889677AC genotype had significantly decreased cancer risk (odds ratio [OR]  = 0.85, 95% confidence interval [CI]  = 0.69-1.01) compared to subjects homozygous carriers of rs10889677AA, the risk decreased even further in those carrying rs10889677CC genotype (OR = 0.64, 95% CI = 0.44-0.93). No significant association was found between the other three polymorphisms and the risk of ESCC.

CONCLUSION

These findings indicated that rs10889677A>C polymorphism in IL-23R may play a protective role in mediating the risk of ESCC.

Therapy with stem cells in inflammatory bowel disease

Inflammatory bowel disease (IBD) affects a part of the young population and has a strong impact upon quality of life. The underlying etiology is not known, and the existing treatments are not curative. Furthermore, a significant percentage of patients are refractory to therapy. In recent years there have been great advances in our knowledge of stem cells and their therapeutic applications. In this context, autologous hematopoietic stem cell transplantation (HSCT) has been used in application to severe refractory Crohn's disease (CD), with encouraging results. Allogenic HSCT would correct the genetic defects of the immune system, but is currently not accepted for the treatment of IBD because of its considerable risks. Mesenchymal stem cells (MSCs) have immune regulatory and regenerative properties, and low immunogenicity (both autologous and allogenic MSCs). Based on these properties, MSCs have been used via the systemic route in IBD with promising results, though it is still too soon to draw firm conclusions. Their local administration in perianal CD is the field where most progress has been made in recent years, with encouraging results. The next few years will be decisive for defining the role of such therapy in the management of IBD.

NFIL3-deficient mice develop microbiota-dependent, IL-12/23-driven spontaneous colitis

NFIL3 is a transcription factor that regulates multiple immunologic functions. In myeloid cells, NFIL3 is IL-10 inducible and has a key role as a repressor of IL-12p40 transcription. NFIL3 is a susceptibility gene for the human inflammatory bowel diseases. In this article, we describe spontaneous colitis in Nfil3(-/-) mice. Mice lacking both Nfil3 and Il10 had severe early-onset colitis, suggesting that NFIL3 and IL-10 independently regulate mucosal homeostasis. Lymphocytes were necessary for colitis, because Nfil3/Rag1 double-knockout mice were protected from disease. However, Nfil3/Rag1 double-knockout mice adoptively transferred with wild-type CD4(+) T cells developed severe colitis compared with Rag1(-/-) recipients, suggesting that colitis was linked to defects in innate immune cells. Colitis was abrogated in Nfil3/Il12b double-deficient mice, identifying Il12b dysregulation as a central pathogenic event. Finally, germ-free Nfil3(-/-) mice do not develop colonic inflammation. Thus, NFIL3 is a microbiota-dependent, IL-10-independent regulator of mucosal homeostasis via IL-12p40.

Susceptibility to ulcerative colitis in Hungarian patients determined by gene-gene interactions

AIM: To study the inflammatory bowel disease-5 locus (IBD5) and interleukin-23 receptor (IL23R) gene variants in UC patients and test for gene-gene interaction.

METHODS: The study population (n = 625) was comprised of 320 unrelated ulcerative colitis (UC) patients with Caucasian origin and 316 age- and gender-matched, healthy controls. Five variants in the IBD5 locus (IGR2198a_1 rs11739135, IGR2096a_1 rs12521868, IGR2230a_1 rs17622208, SLC22A4 rs1050152 and SLC22A5 rs2631367) and two of the IL23R gene (rs1004819, rs2201841) were analysed. PCR and restriction fragment length polymorphism methods were used for genotyping, the SLC22A4 rs1050152 genotypes were determined by direct sequencing. Interactions and specific genotype combinations of the seven variants were tested by binary logistic regression analysis. The IL23R genotypes were stratified by IBD5 genotypes for further interaction analyses.

RESULTS: For the IL23R rs1004819 A allele we found significantly higher allele frequency (P = 0.032) in UC patients compared to control subjects. The SNP rs1004819 showed significant association with UC risk for carriers (P = 0.004, OR = 1.606; 95%CI: 1.160-2.223) and the SNP rs2201841 for homozygotes (P = 0.030, OR = 1.983; 95%CI: 1.069-3.678). Individually none of the IBD5 markers conferred risk to UC development. There was no evidence for statistical interaction either between IBD5 loci and IL23R genes using logistic regression analysis. After genotype stratification, we could detect a positive association on the background of rs1004819 A allele for SLC22A4 T, SLC22A5 C, IGR2198a_1 C or IGR2096a_1 T allele, the highest OR was calculated in the presence of SLC22A4 T allele (P = 0.005, OR = 2.015; 95%CI: 1.230-3.300). There was no association with UC for any combinations of rs1004819 and IGR2230a_1. The IL23R rs2201841 homozygous genotype and IBD5 carrier status together did not confer susceptibility for UC.

CONCLUSION: The present study has shown that UC susceptibility genes are likely to act in a complex interactive manner similar to CD.

Innate immunity and inflammatory bowel disease: a review of clinical evidence and future application

Inflammatory bowel disease (IBD) is a chronic inflammatory disorder caused by dysregulated immune responses in a genetically predisposed individual. Recent accumulating data, including genome-wide association studies, have identified >100 distinct genetic loci that confer susceptibility. We highlight how the dysregulation of host-microbial interaction leads to intestinal inflammation, particularly with respect to the overlap of common genetic and pathophysiological mechanisms of IBD.

Association between variants of the autophagy related gene--IRGM and susceptibility to Crohn's disease and ulcerative colitis: a meta-analysis

Background

Polymorphisms in immunity-related GTPase family M (IRGM) gene may be associated with inflammatory bowel disease (IBD) by affecting autophagy. However, the genetic association studies on three common variants in IRGM gene (rs13361189, rs4958847 and rs10065172) have shown inconsistent results.

Methodology/ Principal Findings

The PubMed and Embase were searched up to June 5, 2013 for studies on the association between three IRGM polymorphisms and IBD risk. Data were extracted and the odd ratios (ORs) and 95% confidence intervals (95% CIs) were calculated. Finally, we performed a meta-analysis of 25 eligible studies in 3 SNPs located at IRGM gene by using a total of 20590 IBD cases and 27670 controls. The analysis showed modest significant association for the rs13361189, rs4958847 and rs10065172 variants in Crohn’s disease (CD): the risk estimates for the allele contrast were OR=1.306 (1.200-1.420), p=5.2×10^-10, OR=1.182 (1.082-1.290), p=0.0002, and OR=1.248 (1.057-1.473), p=0.009 respectively (still significant when the p value was Bonferroni adjusted to 0.017). When stratified by ethnicity, significantly increased CD risk was observed in Europeans, but not in Asians. Conversely, there was no association of rs13361189 or rs4958847 variant with risk of ulcerative colitis (UC).

Conclusions/ Significance

These results indicated that autophagy gene-IRGM polymorphisms appear to confer susceptibility to CD but not UC, especially in Europeans. Our data may provide further understanding of the role of autophagy in the pathogenesis of CD.

Identifying and testing candidate genetic polymorphisms in the irritable bowel syndrome (IBS): association with TNFSF15 and TNFα

OBJECTIVES

The postinfectious irritable bowel syndrome (PI-IBS) suggests that impaired resolution of inflammation could cause IBS symptoms. The authors hypothesised that polymorphisms in genes whose expression were altered by gastroenteritis might be linked to IBS with diarrhoea (IBS-D) which closely resembles PI-IBS.

DESIGN

Part 1: 25 healthy volunteers (HVs), 21 patients 6 months after Campylobacter jejuni infection, 37 IBS-D and 19 IBS with constipation (IBS-C) underwent rectal biopsy for gene expression analysis and peripheral blood mononuclear cell cytokine production assessment. Part 2: Polymorphisms in genes whose expression was altered in Part 1 were assessed in 179 HV, 179 IBS-D, 122 IBS-C and 41 PI-IBS.

RESULTS

Part 1: Mucosal expression of seven genes was altered in IBS: CCL11, CCL13, Calpain 8 and TNFSF15 increased while NR1D1, GPR161 and GABRE decreased with similar patterns after infection with C jejuni. Part 2: The authors assessed 21 known single nucleotide polymorphisms (SNPs) in these seven genes and one SNP in each of the TNFα and IL-10 genes. Three out of five TNFSF15 SNPs (rs6478108, rs6478109 and rs7848647) showed reduced minor allele frequency (MAF) (0.28, 0.27 and 0.27) in subjects with IBS-D compared with HV (0.38, 0.36 and 0.37; p=0.007, 0.015 and 0.007, respectively) confirming others recent findings. The authors also replicated the previously reported association of the TNFα SNP rs1800629 with PI-IBS which showed an increase in the MAF at 0.30 versus 0.19 for HV (p=0.04).

CONCLUSION

IBS-D and PI-IBS patients are associated with TNFSF15 and TNFα genetic polymorphisms which also predispose to Crohn's disease suggesting possible common underlying pathogenesis.

Effects of enteral nutrition on Crohn's disease: clues to the impact of diet on disease pathogenesis

Crohn's disease is a complex inherited disorder of unknown pathogenesis with environmental, genetic, and microbial factors involved in the development of the disease. A remarkable feature of this disease, especially, but not limited to childhood, is the effective response to exclusive enteral nutrition therapy and the observed benefit from exclusion of normal diet (principle of exclusivity). We reviewed the possible mechanisms of action of enteral nutrition for induction of remission and provided a hypothetical model (herein termed bacterial penetration cycle) that integrates dietary components, bacteria, susceptibility genes, and the innate immune response in the pathogenesis of Crohn's disease.

Autophagy as an innate immune modulator

Autophagy is a fundamental cellular process in eukaryotic cells for maintaining homeostasis by degrading cellular proteins and organelles. Recently, the roles of autophagy have been expanded to immune systems, which in turn modulate innate immune responses. More specifically, autophagy acts as a direct effector for protection against pathogens, as well as a modulator of pathogen recognition and downstream signaling in innate immune responses. In addition, autophagy controls autoimmunity and inflammatory disorders by negative regulation of immune signaling. In this review, we focus on recent advances in the role of autophagy in innate immune systems.