S100A12: a noninvasive marker of inflammation in inflammatory bowel disease

Inflammatory bowel diseases are incurable conditions that feature gut inflammation. Standard markers have inadequate sensitivity and specificity. S100A12 is a new fecal marker that has promise as a non-invasive indicator of gut inflammation. This article reviews recent studies focusing on S100A12 and highlights the current and potential roles of this biomarker.

Intestinal microbiota: a source of novel biomarkers in inflammatory bowel diseases?

The human intestine harbours a complex microbial ecosystem that performs manifold functions important to the nutrition and health of its host. Extensive study has revealed that the composition of the intestinal microbiota is altered in individuals with inflammatory bowel disease (IBD). The IBD associated intestinal microbiota generally has reduced species richness and diversity, lower temporal stability, and disruption of the secreted mucus layer structure. Multiple studies have identified certain bacterial taxa that are enriched or depleted in IBD including Enterobacteriaceae, Ruminococcus gnavus, and Desulfovibrio (enriched) and Faecalibacterium prausnitzii, Lachnospiraceae, and Akkermansia (depleted). Additionally, the relative abundance of some taxa appears to correlate with established markers of disease activity such as Enterobacteriaceae (enriched) and Lachnospiraceae (depleted). Signature shifts in fecal microbial community composition may therefore prove to be valuable as diagnostic biomarkers, particularly for longitudinal monitoring of disease activity and response to treatments.

IRGM variants and susceptibility to inflammatory bowel disease in the German population

Background & Aims

Genome-wide association studies identified the autophagy gene IRGM to be strongly associated with Crohn's disease (CD) but its impact in ulcerative colitis (UC), its phenotypic effects and potential epistatic interactions with other IBD susceptibility genes are less clear which we therefore analyzed in this study.

Methodology/Principal Findings

Genomic DNA from 2060 individuals including 817 CD patients, 283 UC patients, and 961 healthy, unrelated controls (all of Caucasian origin) was analyzed for six IRGM single nucleotide polymorphisms (SNPs) (rs13371189, rs10065172 = p.Leu105Leu, rs4958847, rs1000113, rs11747270, rs931058). In all patients, a detailed genotype-phenotype analysis and testing for epistasis with the three major CD susceptibility genes NOD2, IL23R and ATG16L1 were performed.

Our analysis revealed an association of the IRGM SNPs rs13371189 (p = 0.02, OR 1.31 [95% CI 1.05–1.65]), rs10065172 = p.Leu105Leu (p = 0.016, OR 1.33 [95% CI 1.06–1.66]) and rs1000113 (p = 0.047, OR 1.27 [95% CI 1.01–1.61]) with CD susceptibility. There was linkage disequilibrium between these three IRGM SNPs. In UC, several IRGM haplotypes were weakly associated with UC susceptibility (p<0.05). Genotype-phenotype analysis revealed no significant associations with a specific IBD phenotype or ileal CD involvement. There was evidence for weak gene-gene-interaction between several SNPs of the autophagy genes IRGM and ATG16L1 (p<0.05), which, however, did not remain significant after Bonferroni correction.

Conclusions/Significance

Our results confirm IRGM as susceptibility gene for CD in the German population, supporting a role for the autophagy genes IRGM and ATG16L1 in the pathogenesis of CD.

Endoplasmic reticulum aminopeptidase 1 and interleukin-23 receptor in ankylosing spondylitis

Endoplasmic reticulum aminopeptidase 1 (ERAP1) and interleukin-23 receptor (IL-23R) gene polymorphisms were found to be associated with ankylosing spondylitis (AS) in a nonsynonymous single nucleotide polymorphism association study, and this has been replicated in several studies across different populations. ERAP1 variants could lead to significant changes in the repertoire of peptides presented by MHC-I. Reading this in conjunction with the known association of AS with HLA-B27, a functional interaction between ERAP1 and HLA-B27 is very likely. ERAP1 has additionally been shown to be involved in cytokine receptor shedding. The IL-23R is one of the two receptors that mediate the action of IL-23. AS is associated with the same polymorphisms of IL-23R as those linked to psoriasis and inflammatory bowel disease. This suggests common genetic risks linking AS and extra-articular manifestations. This review focuses on the pathogenic potential of these two genes in AS.

Human metastable epiallele candidates link to common disorders

Metastable epialleles (MEs) are mammalian genomic loci where epigenetic patterning occurs before gastrulation in a stochastic fashion leading to systematic interindividual variation within one species. Importantly, periconceptual nutritional influences may modulate the establishment of epigenetic changes, such as DNA methylation at MEs. Based on these characteristics, we exploited Infinium HumanMethylation450 BeadChip kits in a 2-tissue parallel screen on peripheral blood leukocyte and colonic mucosal DNA from 10 children without identifiable large intestinal disease. This approach led to the delineation of 1776 CpG sites meeting our criteria for MEs, which associated with 1013 genes. The list of ME candidates exhibited overlaps with recently identified human genes (including CYP2E1 and MGMT, where methylation has been associated with Parkinson disease and glioblastoma, respectively) in which perinatal DNA methylation levels where linked to maternal periconceptual nutrition. One hundred 18 (11.6%) of the ME candidates overlapped with genes where DNA methylation correlated (r > 0.871; p < 0.055) with expression in the colon mucosa of 5 independent control children. Genes involved in homophilic cell adhesion (including cadherin-associated genes) and developmental processes were significantly overrepresented in association with MEs. Additional filtering of gene expression-correlated MEs defined 35 genes, associated with 2 or more CpG sites within a 10 kb genomic region, fulfilling the ME criteria. DNA methylation changes at a number of these genes have been linked to various forms of human disease, including cancers, such as asthma and acute myeloid leukemia (ALOX12), gastric cancer (EBF3), breast cancer (NAV1), colon cancer and acute lymphoid leukemia (KCNK15), Wilms tumor (protocadherin gene cluster; PCDHAs) and colorectal cancer (TCERG1L), suggesting a potential etiologic role for MEs in tumorigenesis and underscoring the possible developmental origins of these malignancies. The presented compendium of ME candidates may accelerate our understanding of the epigenetic origins of common human disorders.

M89V Sialic acid Acetyl Esterase (SIAE) and all other non-synonymous common variants of this gene are catalytically normal

Catalytically defective rare variants of Sialic acid Acetyl Esterase (SIAE) have previously been linked to autoimmunity. Studies presented here confirm that the M89V SIAE protein and all other products of common variant alleles of SIAE are catalytically normal. Although overexpressing transfected non-lymphoid cells secrete small amounts of SIAE that can associate with the cell surface, normal human lymphocytes do not exhibit cell surface SIAE, supporting genetic evidence in mice that indicates that this protein functions in a lymphocyte intrinsic manner. Analyses of the plasma proteome also indicate that SIAE is not secreted in vivo. A re-analysis exclusively of catalytically defective rare variant alleles of SIAE in subjects in which this gene was completely sequenced confirmed an association of SIAE with autoimmunity. A subset of catalytically defective rare variant SIAE alleles has previously been typed in a large genotyping study comparing a diverse group of disease subjects and controls; our re-analysis of this data shows that catalytically defective alleles are enriched in disease subjects. These data suggest that SIAE may be associated with autoimmunity and that further study of catalytically defective rare variant SIAE alleles in terms of autoimmune disease susceptibility is strongly warranted.

The cell biology of the intestinal epithelium and its relation to inflammatory bowel disease

The epithelial layer of our intestines must meet two opposing requirements. On one hand it must allow for efficient uptake of nutrients and fluids, on the other hand it is a vital defence barrier between the milieu interior and the milieu exterior. In contrast to the lung that by virtue of cilia movement is kept virtually sterile, the gut epithelium is confronted by a stupendous microbiological load and a substantial xenobiotic challenge. The efficiency by which our intestinal epithelium manages to deal with the challenge of efficient nutrient absorption while simultaneously fulfilling its barrier function is testimony to what the forces of evolution can accomplish. Importantly, our understanding as to how our gut epithelial compartment manages this balancing act is now rapidly emerging, answering one of the oldest questions in cell biology. Importantly, when aberrations in this balance occur, for instance as a consequence genetic polymorphisms, increased propensity to develop chronic inflammation and inflammatory bowel disease is the result. Thus the knowledge on intestinal cell biology and biochemistry is not only of academic interest but may also aid design of novel avenues for the rational treatment of mucosal disease.

Promises, delivery, and challenges of inflammatory bowel disease risk gene discovery

Over the past two decades, investigators have used whole genome linkage and genome-wide association studies, including the "Immunochip" study, to identify a surprising number (over 163) of genetic loci containing susceptibility genes for inflammatory bowel disease (IBD) and its 2 major phenotypes, Crohn's disease (CD) and ulcerative colitis (UC). These loci, although nearly all low-risk, have provided important lessons regarding the nature of IBD etiopathogenesis, including that most loci cause both CD and UC risk; one-third of loci have risk for other common autoimmune diseases; numerous loci contain genes that regulate immunity to microbes; Th17 cells are disproportionately influenced by genes within IBD loci; and the HLA region influences UC far greater than CD. Interleukin-10 receptor subunit (IL10RA and IL10RB) and IL10 cytokine gene mutations cause a rare, severe, infantile-onset, autosomal recessive CD, and this knowledge has allowed curative treatment by bone marrow transplant. Key tasks for broader clinical translation include discovery of risk variants for non-white populations; discovery of the less frequent but higher penetrance and familial risk variants by next-generation sequencing; and determining which of numerous associated variations within loci result in specific gene dysfunction causing IBD risk-as only a small number of genes within IBD loci, including NOD2, IL23R, ATG16L1, IRGM, and PTPN22 have specific functional variations characterized. Studying the effect of IBD susceptiblity gene dysfunctions in tissue cultures and animal models will allow the ultimate translational benefits of developing novel treatments for and potentially preventing IBD in those having specific genetic risk factors.

Modulating the human gut microbiome as an emerging therapeutic paradigm

The human body is actually a vast and changing ecosystem comprised of billions of microbial organisms, known collectively as the microbiome. Within the last few years, the study of the microbiome and its impact on human health has been a rapidly growing area of biomedical science. The gut intestinal tract microbiome has been a particular focus of research given its potential role in many inflammatory and metabolic diseases as well as drug metabolism. Although a nascent field, the potential for modulating the gut microbiome or human host interactions associated with these microbes offers new therapeutic strategies for many chronic diseases, in particular obesity, diabetes and inflammatory bowel diseases. Here we provide an overview of present knowledge about the gut microbiome, its putative role in metabolic diseases and the potential for microbiome focused treatments from the drug development perspective.

The organisation and structure of inflammatory bowel disease services for children and young people in the UK in 2010: significant progress but still room for improvement

BACKGROUND

Inflammatory bowel disease (IBD) is becoming more common in children. While treatment options remain limited the appropriate organisation and delivery of services are an integral part of good care.

METHODS

All eligible UK paediatric sites were invited to submit data for organisation of paediatric IBD services as of 1 September 2010. Comparison, when relevant, was made with the previous paediatric audit (2008) and the concurrently running adult audit.

RESULTS

24/25 (96%) of sites submitted data. The median number of patients managed and the median number of new IBD (ulcerative colitis and Crohn's disease only) cases per annum was 178 (IQR 136-281) and 32 (IQR 23-50), respectively. There was an increase in the IBD workforce including whole-time equivalent (WTE) IBD nurses (1.0 vs 1.5 WTE nurses, p=0.02). 1023 patients 16 years and younger were looked after in the 202 adult sites who submitted data; only 78/202 sites indicated they cared for 16-year-old and younger children; approximately half of these 78 sites had age-appropriate support facilities. Most paediatric sites have access to urgent endoscopy (83%), telephone advice (100%) and urgent clinic appointments (91%). Most sites did not have: shared care pathways with primary care (74%), annual reviews (71%), real time patient management systems (83%) and research network trial participation (78%).

CONCLUSIONS

Many aspects of paediatric IBD care in the UK are good and have shown significant improvement over recent years. There are areas in need of further change and specific regional and national action plans should address identified deficiencies before any future audit of paediatric and adult IBD services.

Serum infliximab concentrations in pediatric inflammatory bowel disease

OBJECTIVE

To study serum infliximab (s-IFX) levels in pediatric patients with inflammatory bowel disease (IBD).

SUBJECTS AND METHODS

s-IFX trough levels were measured in a total of 133 blood samples of 37 pediatric IBD patients (Crohn's disease, 23): 48 during the induction phase (weeks 2 and 6) and 85 during maintenance treatment. Antibodies to infliximab (ATI) were determined in 93 samples (30 patients). s-IFX values were related to fecal calprotectin (FC) and serum markers of inflammation.

RESULTS

During induction (5 mg/kg) and maintenance therapy, the median s-IFX levels were 17.6 μg/ml (range 0-48 μg/ml) and 3.55 μg/ml (range 0-40 μg/ml), respectively. The IFX levels were similar in ulcerative colitis and Crohn's disease (e.g. during maintenance median 3.2 vs. 2.8 μg/ml, p = 0.718), thus the data are pooled. During induction, the s-IFX level was associated with the total dose of IFX, that is, young children with lower body weight had lower levels (p < 0.001 at week 2 and p < 0.05 at week 6). Shorter administration interval resulted in higher trough levels (p < 0.005). All samples with undetectable s-IFX (6.8%) levels presented ATI. High inflammation (FC >1000 µg/g) during induction was associated with lower s-IFX levels (median 4.0 μg/ml, range 0.47-25 compared to median 20 μg/ml, range 0-48 when FC <1000 µg/g, p < 0.005). There was no significant association between the ESR or values of C-reactive protein and s-IFX levels during induction.

CONCLUSIONS

In pediatric IBD, lower body weight and higher level of intestinal inflammation are associated to s-IFX levels during induction but relation to therapeutic response is unclear.

Increasing incidence of pediatric inflammatory bowel disease in Spain (1996-2009): the SPIRIT Registry

BACKGROUND

Although pediatric inflammatory bowel disease (IBD) diagnosis has increased in the last decades in Spain, there are no consistent epidemiologic data. Our aim was to describe the changing pattern of pediatric IBD incidence in Spain in the last 14 years.

METHODS

A retrospective survey of patients diagnosed below 18 years of age in the period 1996-2009 was performed. Patients' data were obtained from the hospitals' databases. To avoid reduced accrual of cases diagnosed by adult physicians, adult IBD units in referral centers were invited to participate. Seventy-eight centers participated in our survey. Rates of incidence were calculated using age-stratified population-based epidemiologic data. Incidence rates were compared for the last 14 years (1996-2009).

RESULTS

In total, data from 2107 patients were obtained: 1,165 Crohn's disease (CD, 55.3%), 788 ulcerative colitis (UC, 37.4%), and 154 IBD unclassified. The sex distribution was 56.4% male, with higher predominance for CD (59.3%) as compared to UC (52.8%) and IBD unclassified (53.2%) (P = 0.012). The median age at diagnosis was 12.3 years (p25-75 9.7-14.6) with significant differences between diseases. IBD incidence increased from 0.97 to 2.8/100,000 inhabitants <18 years/year in the study period. Although this increase is more evident for CD (from 0.53 to 1.7), UC has also risen considerably (0.39 to 0.88).

CONCLUSIONS

This is the first attempt to calculate the current incidence of pediatric IBD in Spain. A significant increase of incidence rates in the study period was observed. In the last 14 years pediatric IBD incidence has almost tripled, with a more important CD increase.

Association between Helicobacter Pylori infection and ulcerative colitis--a case control study from China

AIMS

To investigate the association between H. pylori infection and UC prevalence in China.

MATERIALS AND METHODS

Subjects were selected from patients admitted in Department of Gastroenterology for abdominal pain, hematochezia, diarrhea and other GI symptoms during 2009-2012. UC diagnosis was based on both colonoscopy and biopsy. H. pylori detection was based on (14)C urea breath test (UBT) and biopsy sample culture. Patients' demographic, anthropometric and serologic data were selected. H. pylori infection rate was compared between UC and control groups, followed by a subgroup analysis on the association between H. pylori infection and extent and severity degree of UC.

RESULTS

Totally, 153 and 121 patients were selected and divided into UC and control groups. There were no significant differences in age, gender, BMI, hypertension and diabetes. However, smoking history was significantly lower while WBC and CRP levels were significantly higher in UC group. The H. pylori infection rate in UC group was 30.5%, significantly lower than that of 57.0% in control group. The H. pylori infection rate in UC of left colon and whole colon were 33,9% and 24.2% (p<0.05 between them), both significantly lower than that in control group. In addition, the H. pylori infection rates in mild, moderate and severe UC subgroups were 37.8%, 32.3% and 22.2% (p>0.05 among them), all of which were significantly lower than that in control group.

CONCLUSION

We reported a significantly lower H. pylori infection rate in UC patients with different extent and severity degree, which provides evidence for bacteria involvement in UC pathogenesis and reminder clinicians to keep cautious in considering H. pylori eradication in UC patients.

PTGER4 expression-modulating polymorphisms in the 5p13.1 region predispose to Crohn's disease and affect NF-κB and XBP1 binding sites

Background

Genome-wide association studies identified a PTGER4 expression-modulating region on chromosome 5p13.1 as Crohn's disease (CD) susceptibility region. The study aim was to test this association in a large cohort of patients with inflammatory bowel disease (IBD) and to elucidate genotypic and phenotypic interactions with other IBD genes.

Methodology/Principal Findings

A total of 7073 patients and controls were genotyped: 844 CD and 471 patients with ulcerative colitis and 1488 controls were analyzed for the single nucleotide polymorphisms (SNPs) rs4495224 and rs7720838 on chromosome 5p13.1. The study included two replication cohorts of North American (CD: n = 684; controls: n = 1440) and of German origin (CD: n = 1098; controls: n = 1048). Genotype-phenotype, epistasis and transcription factor binding analyses were performed. In the discovery cohort, an association of rs4495224 (p = 4.10×10⁻⁵; 0.76 [0.67–0.87]) and of rs7720838 (p = 6.91×10⁻⁴; 0.81 [0.71–0.91]) with susceptibility to CD was demonstrated. These associations were confirmed in both replication cohorts. In silico analysis predicted rs4495224 and rs7720838 as essential parts of binding sites for the transcription factors NF-κB and XBP1 with higher binding scores for carriers of the CD risk alleles, providing an explanation of how these SNPs might contribute to increased PTGER4 expression. There was no association of the PTGER4 SNPs with IBD phenotypes. Epistasis detected between 5p13.1 and ATG16L1 for CD susceptibility in the discovery cohort (p = 5.99×10⁻⁷ for rs7720838 and rs2241880) could not be replicated in both replication cohorts arguing against a major role of this gene-gene interaction in the susceptibility to CD.

Conclusions/Significance

We confirmed 5p13.1 as a major CD susceptibility locus and demonstrate by in silico analysis rs4495224 and rs7720838 as part of binding sites for NF-κB and XBP1. Further functional studies are necessary to confirm the results of our in silico analysis and to analyze if changes in PTGER4 expression modulate CD susceptibility.

Intestinal anti-inflammatory activity of red wine extract: unveiling the mechanisms in colonic epithelial cells

The development of new therapeutic approaches, combining efficacy and safety against intestinal inflammation, notably inflammatory bowel disease (IBD), has emerged as an important goal due to the significant side effects and the lack of effectiveness of standard current therapies. Recently, several studies described the health-promoting effects of red wine, including anti-inflammatory properties, but the molecular mechanisms underlying its beneficial role remain largely unknown. Red wine is rich in phenolic compounds and it has been suggested that the positive effect of red wine intake might be attributed not only to the antioxidant properties of these compounds but also to the modulation of signalling cascades in connection with physiological and pathophysiological conditions such as inflammatory processes. This study assesses the potential anti-inflammatory action of a red wine extract (RWE) enriched in polyphenols in a cellular model of intestinal inflammation using cytokines-stimulated HT-29 colon epithelial cells. RWE suppressed cytokines-induced IκB degradation and interleukin-8 production in a dose-dependent manner. Coherently, key inflammatory mediators downstream NF-κB activation; notably cyclooxygenase-2 and inducible nitric oxide synthase were maintained at low levels by RWE in the presence of the cytokines. Additionally, RWE inhibited both the increase of nitric oxide derived from iNOS and of protein tyrosine nitration, a biomarker of nitrosative stress that typically requires the reaction of nitric oxide with the superoxide radical. Taken together, the anti-inflammatory action of RWE, mechanistically supported by the modulation of cascades orchestrated by NF-κB and involving nitric oxide, suggests that RWE (a readily straightforward preparation when compared with the purification of specific compounds) may represent a simple and inexpensive therapeutic strategy in the context of intestinal inflammation.

Effect of bowel cleansing for colonoscopy on fecal calprotectin levels in pediatric patients

The recent development of easily applicable fecal surrogate markers of intestinal inflammation, such as fecal calprotectin (FC), has provided a new means for objectively assessing disease activity in patients with chronic inflammatory bowel disease. Because the use of these markers is about to emerge, it is important to be aware of the possible limitations of measurements. We assessed levels of FC during bowel cleansing. In patients with high FC levels at baseline, the values measured during bowel cleansing varied considerably, remaining high or even returning to normal. Thus, stool sampling for FC assessment is not recommended during bowel preparation for colonoscopy.

Microbiota of de-novo pediatric IBD: increased Faecalibacterium prausnitzii and reduced bacterial diversity in Crohn's but not in ulcerative colitis

OBJECTIVES

The gastrointestinal microbiota is considered important in inflammatory bowel disease (IBD) pathogenesis. Discoveries from established disease cohorts report reduced bacterial diversity, changes in bacterial composition, and a protective role for Faecalibacterium prausnitzii in Crohn's disease (CD). The majority of studies to date are however potentially confounded by the effect of treatment and a reliance on established rather than de-novo disease.

METHODS

Microbial changes at diagnosis were examined by biopsying the colonic mucosa of 37 children: 25 with newly presenting, untreated IBD with active colitis (13 CD and 12 ulcerative colitis (UC)), and 12 pediatric controls with a macroscopically and microscopically normal colon. We utilized a dual-methodology approach with pyrosequencing (threshold >10,000 reads) and confirmatory real-time PCR (RT-PCR).

RESULTS

Threshold pyrosequencing output was obtained on 34 subjects (11 CD, 11 UC, 12 controls). No significant changes were noted at phylum level among the Bacteroidetes, Firmicutes, or Proteobacteria. A significant reduction in bacterial α-diversity was noted in CD vs. controls by three methods (Shannon, Simpson, and phylogenetic diversity) but not in UC vs. controls. An increase in Faecalibacterium was observed in CD compared with controls by pyrosequencing (mean 16.7% vs. 9.1% of reads, P=0.02) and replicated by specific F. prausnitzii RT-PCR (36.0% vs. 19.0% of total bacteria, P=0.02). No disease-specific clustering was evident on principal components analysis.

CONCLUSIONS

Our results offer a comprehensive examination of the IBD mucosal microbiota at diagnosis, unaffected by therapeutic confounders or changes over time. Our results challenge the current model of a protective role for F. prausnitzii in CD, suggesting a more dynamic role for this organism than previously described.

The role of functionally defective rare germline variants of sialic acid acetylesterase in autoimmune Addison's disease

BACKGROUND

Autoimmune Addison's disease (AAD) is a rare condition with a complex genetic basis. A panel of rare and functionally defective genetic variants in the sialic acid acetylesterase (SIAE) gene has recently been implicated in several common autoimmune conditions. We performed a case-control study to determine whether these rare variants are associated with a rarer condition, AAD.

METHOD

We analysed nine SIAE gene variants (W48X, M89V, C196F, C226G, R230W, T312M, Y349C, F404S and R479C) in a United Kingdom cohort of 378 AAD subjects and 387 healthy controls. All samples were genotyped using Sequenom iPlex chemistry to characterise primer extension products.

RESULTS

A heterozygous rare allele at codon 312 (312*M) was found in one AAD patient (0.13%) but was not detected in the healthy controls. The commoner, functionally recessive variant at codon 89 (89*V) was found to be homozygous in two AAD patients but was only found in the heterozygous state in controls. Taking into account all nine alleles examined, 4/378 (1.06%) AAD patients and 1/387 (0.25%) healthy controls carried the defective SIAE alleles, with a calculated odds ratio of 4.13 (95% CI 0.44-97.45, two-tailed P value 0.212, NS).

CONCLUSION

We demonstrated the presence of 89*V homozygotes and the 312*M rare allele in the AAD cohort, but overall, our analysis does not support a role for rare variants in SIAE in the pathogenesis of AAD. However, the relatively small collection of AAD patients limits the power to exclude a small effect.

History of and current issues affecting surgery for pediatric ulcerative colitis

Pediatric ulcerative colitis (UC) is reportedly more extensive and progressive in its clinical course than adult UC. Therefore, more aggressive initial therapies and more frequent colectomies are needed. When physicians treat pediatric UC, they must consider the therapeutic outcome as well as the child's physical and psychological development. Mucosal proctocolectomy with ileal J-pouch anal anastomosis is currently recommended as a standard curative surgical procedure for UC in both children and adults worldwide. This procedure was developed 100 years after the first surgical therapy, which treated UC by colon irrigation through a temporary inguinal colostomy. Predecessors in the colorectal and pediatric surgical fields have struggled against several postoperative complications and have long sought a surgical procedure that is optimal for children. We herein describe the history of the development of surgical procedures and the current issues regarding the surgical indications for pediatric UC. These issues differ from those in adults, including the definition of toxic megacolon on plain X-rays, the incidence of colon carcinoma, preoperative and postoperative steroid complications, and future growth. Surgeons treating children with UC should consider the historical experiences of pioneer surgeons to take the most appropriate next step to improve the surgical outcomes and patients' quality of life.

Mycobacterium avium subsp. paratuberculosis lipophilic antigen causes Crohn's disease-type necrotizing colitis in Mice

Background: A 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced murine colitis model was developed to investigate the pathogenesis and to evaluate a method of treating human Crohn’s disease. This experimental model rapidly induces colitis similar to human Crohn’s disease lesion in a reproducible manner. However, natural exposure of the human digestive tract to TNBS is unrealistic. A novel animal model based on realistic data is eagerly anticipated in future research on pathogenesis of CD. Method: We evaluated the potency of Map antigen molecules in an effort to develop a novel colitis model using a more realistic source than TNBS. We prepared the Map antigen by ethanol extraction and developed a mouse model in a manner similar to that of the well-known TNBS-induced colitis in mice. In the experiment, seven days after subcutaneous (SC) injection of the antigen into normal C57BL/6 mice, the same antigen in 50% ethanol was injected into the colon by the transanal route with a fine cannula. Results: On the fifth day after the transanal injection, histopathological examination revealed full-thickness necrotizing colitis with erosion and ulcers; severe infiltration with neutrophils, lymphocytes, macrophages, and perforation. However, no change was detected with each single Map-antigen injection. Conclusion: The present results provide a novel animal model for research on CD and may be the key to clarifying the relationship between CD and Map. This is the first evidence that mycobacterium antigen induces necrotizing colitis.

NOD1 and NOD2 Signaling in Infection and Inflammation

Sensing intracellular pathogens is a process mediated by innate immune cells that is crucial for the induction of inflammatory processes and effective adaptive immune responses against pathogenic microbes. NOD-like receptors (NLRs) comprise a family of intracellular pattern recognition receptors that are important for the recognition of damage and microbial-associated molecular patterns. NOD1 and NOD2 are specialized NLRs that participate in the recognition of a subset of pathogenic microorganisms that are able to invade and multiply intracellularly. Once activated, these molecules trigger intracellular signaling pathways that lead to the activation of transcriptional responses culminating in the expression of a subset of inflammatory genes. In this review, we will focus on the role of NOD1 and NOD2 in the recognition and response to intracellular pathogens, including Gram-positive and Gram-negative bacteria, and on their ability to signal in response to non-peptidoglycan-containing pathogens, such as viruses and protozoan parasites.

Crohn's and colitis in children and adolescents

Crohn's disease and ulcerative colitis can be grouped as the inflammatory bowel diseases (IBD). These conditions have become increasingly common in recent years, including in children and young people. Although much is known about aspects of the pathogenesis of these diseases, the precise aetiology is not yet understood, and there remains no cure. Recent data has illustrated the importance of a number of genes-several of these are important in the onset of IBD in early life, including in infancy. Pain, diarrhoea and weight loss are typical symptoms of paediatric Crohn's disease whereas bloody diarrhoea is more typical of colitis in children. However, atypical symptoms may occur in both conditions: these include isolated impairment of linear growth or presentation with extra-intestinal manifestations such as erythema nodosum. Growth and nutrition are commonly compromised at diagnosis in both Crohn's disease and colitis. Consideration of possible IBD and completion of appropriate investigations are essential to ensure prompt diagnosis, thereby avoiding the consequences of diagnostic delay. Patterns of disease including location and progression of IBD in childhood differ substantially from adult-onset disease. Various treatment options are available for children and adolescents with IBD. Exclusive enteral nutrition plays a central role in the induction of remission of active Crohn's disease. Medical and surgical therapies need to considered within the context of a growing and developing child. The overall management of these chronic conditions in children should include multi-disciplinary expertise, with focus upon maintaining control of gut inflammation, optimising nutrition, growth and quality of life, whilst preventing disease or treatment-related complications.

Epigenetics in inflammatory bowel disease

PURPOSE OF REVIEW

To briefly summarize some of the principles of epigenetics and assess their potential relevance for the disease pathogenesis of inflammatory bowel diseases (IBDs). To review the results of recent IBD-related epigenetic studies, discuss main challenges as well as highlight the opportunities for future research in this field.

RECENT FINDINGS

Evidence is accumulating for a major role of epigenetic mechanisms in the disease pathogenesis of several immune-mediated diseases. Recent findings indicate that epigenetics may mediate some of the effects of environment, genetic predisposition and intestinal microbiota on IBD pathogenesis.

SUMMARY

Epigenetics is a rapidly expanding and hugely promising area of research. At best, it may provide a unifying molecular mechanism to explain complex immune-mediated diseases such as IBD. Future research studies must be carefully designed, performed and analysed taking into account the basic principles of epigenetics in order to ensure the true potential of this field is realized in the understanding of IBD.

Inflammatory bowel disease: a Canadian burden of illness review

BACKGROUND

Inflammatory bowel diseases (IBD) - Crohn's disease (CD) and ulcerative colitis (UC) - significantly impact quality of life and account for substantial costs to the health care system and society.

OBJECTIVE

To conduct a comprehensive review and summary of the burden of IBD that encompasses the epidemiology, direct medical costs, indirect costs and humanistic impact of these diseases in Canada.

METHODS

A literature search focused on Canadian data sources. Analyses were applied to the current 2012 Canadian population.

RESULTS

There are approximately 233,000 Canadians living with IBD in 2012 (129,000 individuals with CD and 104,000 with UC), corresponding to a prevalence of 0.67%. Approximately 10,200 incident cases occur annually. IBD can be diagnosed at any age, with typical onset occurring in the second or third decade of life. There are approximately 5900 Canadian children <18 years of age with IBD. The economic costs of IBD are estimated to be $2.8 billion in 2012 (almost $12,000 per IBD patient). Direct medical costs exceed $1.2 billion per annum and are driven by cost of medications ($521 million), hospitalizations ($395 million) and physician visits ($132 million). Indirect costs (society and patient costs) total $1.6 billion and are dominated by long-term work losses of $979 million. Compared with the general population, the quality of life patients experience is low across all dimensions of health.

CONCLUSIONS

The present review documents a high burden of illness from IBD due to its high prevalence in Canada combined with high per-patient costs. Canada has among the highest prevalence and incidence rates of IBD in the world. Individuals with IBD face challenges in the current environment including lack of awareness of IBD as a chronic disease, late or inappropriate diagnosis, inequitable access to health care services and expensive medications, diminished employment prospects and limited community-based support.

The functional properties of human slow skeletal troponin T isoforms in cardiac muscle regulation

Human slow skeletal troponin T (HSSTnT) shares a high degree of homology with cardiac TnT (CTnT). Although the presence of HSSTnT has not been confirmed in the heart at the protein level, detectable levels of HSSTnT mRNA have been found. Whether HSSTnT isoforms are expressed transiently remains unknown. Because transient re-expression of HSSTnT may be a potential mechanism of regulating function, we explored the effect of HSSTnT on the regulation of cardiac muscle. At least three HSSTnT isoforms have been found to exist in slow skeletal muscle: HSSTnT1 (+exons 5 and 12), HSSTnT2 (+exon 5, -exon 12), and HSSTnT3 (-exons 5 and 12). Another isoform, HSSTnT hypothetical (Hyp) (-exon 5, +exon 12), has only been found at the mRNA level. Compared with HCTnT3 (adult isoform), Tn complexes containing HSSTnT1, -2, and -3 did not alter the actomyosin ATPase activation and inhibition in the presence and absence of Ca(2+), respectively. HSSTnTHyp was not evaluated as it did not form a Tn complex under a variety of conditions. Porcine papillary skinned fibers displaced with HSSTnT1, -2, or -3 and reconstituted with human cardiac troponin I and troponin C (HCTnI·TnC) complex showed a decrease in the Ca(2+) sensitivity of force development and an increase in maximal recovered force (HSSTnT1 and -3) compared with HCTnT3. In contrast, HSSTnTHyp showed an increase in the Ca(2+) sensitivity of force development. This suggests that re- or overexpression of specific SSTnT isoforms might have therapeutic potential in the failing heart because they increase the maximal force of contraction. In addition, circular dichroism and proteolytic digestion experiments revealed structural differences between HSSTnT isoforms and HCTnT3 and that HSSTnT1 is more susceptible to calpain and trypsin proteolysis than the other HSSTnTs. Overall, HSSTnT isoforms despite being homologues of CTnT may display distinct functional properties in muscle regulation.

The microbiota in inflammatory bowel disease: friend, bystander, and sometime-villain

Ulcerative colitis and Crohn's disease, collectively known as inflammatory bowel disease, represent the heterogeneous outcome of three colliding influences: genetic risk factors, environmental modifiers, and immune effector mechanisms of tissue injury. The nature of these inputs is complex, with each having distinct and overlapping contributions to ulcerative colitis and Crohn's disease. Identification of specific genetic risk factors has improved the understanding of specific pathways to disease, but the primacy of environmental or lifestyle factors linked to changes in the gut microbiota, particularly in early life, is increasingly evident. Clarification of the molecular basis of host-microbe interactions in health and in susceptible individuals promises novel therapeutic strategies.

Abnormal genetic and epigenetic changes in signal transducer and activator of transcription 4 in the pathogenesis of inflammatory bowel diseases

BACKGROUND AND AIMS

Changes in the expression of signal transducer and activator of transcription 4 (STAT4) contribute to the development of a variety of autoimmune diseases including inflammatory bowel diseases (IBDs). Moreover, epigenetic modifications, including DNA methylation, are considered a basis for differentiation of T helper cells and regulation of cytokines. In this study, we investigated the methylation status of STAT4 gene in IBD patients and the associations between its genetic and epigenetic alterations in IBD patients.

METHODS

Blood and colonic mucosa samples were obtained from Korean patients with IBD and healthy controls. Peripheral blood mononuclear cells (PBMCs) were isolated, and total RNA and genomic DNA were isolated from the PBMCs and colon mucosa tissues. The mRNA level and DNA methylation status of the promoter were determined by real-time RT-PCR and pyrosequencing, respectively. The chosen SNPs (rs11889341, rs7574865, rs8179673, rs6752770, rs925847, rs10168266, rs10181656, and rs11685878) were genotyped using the TaqMan nuclease assay.

RESULTS

Elevated expression of STAT4 was observed in the colonic mucosa and PBMCs of IBD patients. IBD patients showed a lower degree of methylation of the STAT4 promoter than did the healthy controls. Moreover, a significant correlation between risk alleles and methylation status at -172 of the STAT4 promoter was observed, and mRNA levels of STAT4 in IBD patients were correlated inversely with the T-risk allele (rs7574865).

CONCLUSIONS

Our data demonstrated that the DNA methylation status of STAT4 is associated with genetic polymorphisms, providing insights into the interactions between genetic and epigenetic aberrances in STAT4 that contribute to the development of IBD.

Distinct functional patterns of gene promoter hypomethylation and hypermethylation in cancer genomes

BACKGROUND

Aberrant DNA methylation plays important roles in carcinogenesis. However, the functional significance of genome-wide hypermethylation and hypomethylation of gene promoters in carcinogenesis currently remain unclear.

PRINCIPAL FINDINGS

Based on genome-wide methylation data for five cancer types, we showed that genes with promoter hypermethylation were highly consistent in function across different cancer types, and so were genes with promoter hypomethylation. Functions related to "developmental processes" and "regulation of biology processes" were significantly enriched with hypermethylated genes but were depleted of hypomethylated genes. In contrast, functions related to "cell killing" and "response to stimulus", including immune and inflammatory response, were associated with an enrichment of hypomethylated genes and depletion of hypermethylated genes. We also observed that some families of cytokines secreted by immune cells, such as IL10 family cytokines and chemokines, tended to be hypomethylated in various cancer types. These results provide new hints for understanding the distinct functional roles of genome-wide hypermethylation and hypomethylation of gene promoters in carcinogenesis.

CONCLUSIONS

Genes with promoter hypermethylation and hypomethylation are highly consistent in function across different cancer types, respectively, but these two groups of genes tend to be enriched in different functions associated with cancer. Especially, we speculate that hypomethylation of gene promoters may play roles in inducing immunity and inflammation disorders in precancerous conditions, which may provide hints for improving epigenetic therapy and immunotherapy of cancer.

Management of pediatric ulcerative colitis: joint ECCO and ESPGHAN evidence-based consensus guidelines

BACKGROUND AND AIMS

Pediatric ulcerative colitis (UC) shares many features with adult-onset disease but there are some unique considerations; therefore, therapeutic approaches have to be adapted to these particular needs. We aimed to formulate guidelines for managing UC in children based on a systematic review (SR) of the literature and a robust consensus process. The present article is a product of a joint effort of the European Crohn's and Colitis Organization (ECCO) and the European Society for Paediatric Gastroenterology, Hepatology, and Nutrition (ESPGHAN).

METHODS

A group of 27 experts in pediatric IBD participated in an iterative consensus process including 2 face-to-face meetings, following an open call to ESPGHAN and ECCO members. A list of 23 predefined questions were addressed by working subgroups based on a SR of the literature.

RESULTS

A total of 40 formal recommendations and 68 practice points were endorsed with a consensus rate of at least 89% regarding initial evaluation, how to monitor disease activity, the role of endoscopic evaluation, medical and surgical therapy, timing and choice of each medication, the role of combined therapy, and when to stop medications. A management flowchart, based on the Pediatric Ulcerative Colitis Activity Index (PUCAI), is presented.

CONCLUSIONS

These guidelines provide clinically useful points to guide the management of UC in children. Taken together, the recommendations offer a standardized protocol that allows effective, timely management and monitoring of the disease course, while acknowledging that each patient is unique.

[Dipeptidyl peptidase IV in inflammatory bowel diseases (DPP IV/CD26)]

Inflammatory bowel diseases (Crohn's disease, ulcerative colitis, undetermined colitis) are a group of chronic autoimmune inflammatory diseases distinguished by recurrent inflammation of various parts of the gastrointestinal (GI) system and presenting a significant public health problem. Despite large basic and clinical research, the aetiology of these diseases and the pathogenesis of inflammation itself remain elusive. Previous studies have confirmed a causal relationship between mediators of inflammatory response and molecules involved in the regulation of their biological activity, especially proteases. The aim of this review is to summarise earlier findings on different aspects of inflammatory bowel diseases, paying particular attention to the involvement of dipeptidyl peptidase IV (CD26 molecule, DPP IV/CD26) in the etiopathogenesis of inflammatory processes in the GI tract. Animal studies of colitis have significantly contributed to the understanding and treatment of these diseases, investigations of ulcerative colitis (DSS-colitis) and Crohn's disease (TNBS-colitis) on the murine model in particular.

The role of autophagy in Crohn's disease

(Macro)-autophagy is a homeostatic process by which eukaryotic cells dispose of protein aggregates and damaged organelles. Autophagy is also used to degrade micro-organisms that invade intracellularly in a process termed xenophagy. Genome-wide association scans have recently identified autophagy genes as conferring susceptibility to Crohn’s disease (CD), one of the chronic inflammatory bowel diseases, with evidence suggesting that CD arises from a defective innate immune response to enteric bacteria. Here we review the emerging role of autophagy in CD, with particular focus on xenophagy and enteric E. coli strains with an adherent and invasive phenotype that have been consistently isolated from CD patients with ileal disease.

Review article: vitamin D and inflammatory bowel disease--established concepts and future directions

BACKGROUND

Understanding of the role of vitamin D in health and disease has increased markedly in the past decade, with its involvement extending well beyond traditional roles in calcium and phosphate homeostasis and musculoskeletal health. This conceptual expansion has been underpinned by identification and exploration of components of this axis including vitamin D-binding protein, key enzymes and receptors in multiple cell types, and a greater recognition of nonclassical autocrine and paracrine effects. Its influence in IBD remains uncertain.

AIM

To review the role of vitamin D in bone health, immune regulation and cancer prevention in IBD, and to outline practical issues and limitations of its use.

METHODS

An extensive online literature review including PubMed and Medline.

RESULTS

In patients with IBD, the vitamin D axis provides an important and often underutilised pathway to preserving bone health. Furthermore, an exciting body of clinical and basic science research demonstrates that these pathways may have an integral part to play in regulation of the immune response in IBD, through effects on the intestinal barrier, antigen presenting cells and adaptive T cells. The possibility of chemoprevention requires further study. The optimal target level of 25-hydroxy vitamin D in patients with IBD is currently uncertain, as is the best therapeutic modality.

CONCLUSIONS

Study of vitamin D pathways may result in the development of relatively inexpensive therapeutic options to optimise patient outcomes. Further prospective clinical research is required to address efficacy and long-term safety.

Multifunctional role of dextran sulfate sodium for in vivo modeling of intestinal diseases

Background

Inflammatory bowel diseases (IBDs) are chronic, relapsing disorders that affect the gastrointestinal tract of millions of people and continue to increase in incidence each year. While several factors have been associated with development of IBDs, the exact etiology is unknown. Research using animal models of IBDs is beginning to provide insights into how the different factors contribute to disease development. Oral administration of dextran sulfate sodium (DSS) to mice induces a reproducible experimental colitis that models several intestinal lesions associated with IBDs. The murine DSS colitis model can also be adapted to quantify intestinal repair following injury. Understanding the mechanistic basis behind intestinal repair is critical to development of new therapeutics for IBDs because of their chronic relapsing nature.

Results

The murine DSS colitis model was adapted to provide a system enabling the quantification of severe intestinal injury with impaired wound healing or mild intestinal injury with rapid restoration of mucosal integrity, by altering DSS concentrations and including a recovery phase. We showed that through a novel format for presentation of the clinical disease data, the temporal progression of intestinal lesions can be quantified on an individual mouse basis. Additionally, parameters for quantification of DSS-induced alterations in epithelial cell populations are included to provide insights into mechanisms underlying the development of these lesions. For example, the use of the two different model systems showed that toll-like receptor 9, a nucleic acid-sensing pattern recognition receptor, is important for protection only following mild intestinal damage and suggests that this model is superior for identifying proteins necessary for intestinal repair.

Conclusions

We showed that using a murine DSS-induced experimental colitis model system, and presenting data in a longitudinal manner on a per mouse basis, enhanced the usefulness of this model, and provided novel insights into the role of an innate immune receptor in intestinal repair. By elucidating the mechanistic basis of intestinal injury and repair, we can begin to understand the etiology of IBDs, enabling development of novel therapeutics or prophylactics.

Methyl donor deficiency affects small-intestinal differentiation and barrier function in rats

Dietary methyl donors and their genetic determinants are associated with Crohn's disease risk. We investigated whether a methyl-deficient diet (MDD) may affect development and functions of the small intestine in rat pups from dams subjected to the MDD during gestation and lactation. At 1 month before pregnancy, adult females were fed with either a standard food or a diet without vitamin B12, folate and choline. A global wall hypotrophy was observed in the distal small bowel (MDD animals 0·30 mm v. controls 0·58 mm; P< 0·001) with increased crypt apoptosis (3·37 v. 0·4 %; P< 0·001), loss of enterocyte differentiation in the villus and a reduction in intestinal alkaline phosphatase production. Cleaved caspase-3 immunostaining (MDD animals 3·37 % v. controls 0·4 %, P< 0·001) and the Apostain labelling index showed increased crypt apoptosis (3·5 v. 1·4 %; P= 0·018). Decreased proliferation was observed in crypts of the proximal small bowel with a reduced number of minichromosome maintenance 6 (MDD animals 52·83 % v. controls 83·17 %; P= 0·048) and proliferating cell nuclear antigen-positive cells (46·25 v. 59 %; P= 0·05). This lack of enterocyte differentiation in the distal small bowel was associated with an impaired expression of β-catenin and a decreased β-catenin–E-cadherin interaction. The MDD affected the intestinal barrier in the proximal small bowel by decreasing Paneth cell number after immunostaining for lysosyme (MDD animals 8·66 % v. controls 21·66 %) and by reducing goblet cell number and mucus production after immunostaining for mucin-2 (crypts 8·66 v. 15·33 %; villus 7 v. 17 %). The MDD has dual effects on the small intestine by producing dramatic effects on enterocyte differentiation and barrier function in rats.

Matriptase protects against experimental colitis and promotes intestinal barrier recovery

BACKGROUND

Matriptase is a membrane-anchored serine protease encoded by suppression of tumorigenicity-14 (ST14) that is required for epithelial barrier homeostasis. However, its functional role in inflammatory bowel disease (IBD) is unexplored.

METHODS

Matriptase expression in control, Crohn's disease, and ulcerative colitis tissue specimens was studied by quantitative polymerase chain reaction (qPCR) and immunostaining. Matriptase function was investigated by subjecting St14 hypomorphic and control littermates to dextran sodium sulfate (DSS)-induced colitis and by siRNA silencing in cultured monolayers. Mice were analyzed for clinical, histological, molecular, and cellular effects.

RESULTS

Matriptase protein and ST14 mRNA levels are significantly downregulated in inflamed colonic tissues from Crohn's disease and ulcerative colitis patients. Matriptase-deficient St14 hypomorphic mice administered DSS for 7 days followed by water without DSS for 3 days develop a severe colitis, with only 30% of the St14 hypomorphic mice surviving to day 14, compared with 100% of control littermates. Persistent colitis in surviving St14 hypomorphic mice was associated with sustained cytokine production, an inability to recover barrier integrity, and enhanced claudin-2 expression. Cytokines implicated in barrier disruption during IBD suppress matriptase expression in T84 epithelial monolayers and restoration of matriptase improves barrier integrity in the cytokine-perturbed monolayers.

CONCLUSIONS

These data demonstrate a critical role for matriptase in restoring barrier function to injured intestinal mucosa during colitis, which is suppressed by excessive activation of the immune system. Strategies to enhance matriptase-mediated barrier recovery could be important for intervening in the cycle of inflammation associated with IBD.

Rapid rise in incidence of Irish paediatric inflammatory bowel disease

AIMS

To describe the change in incidence of paediatric inflammatory bowel disease (IBD) observed at the National Centre for Paediatric Gastroenterology, Hepatology and Nutrition, and to determine whether the presenting disease phenotype and disease outcomes have changed during the past decade.

METHODS

The annual incidence of IBD in Irish children aged <16 years was calculated for the years 2000-2010. Two subsets of patients, group A (diagnosed between 1 January 2000 and 31 December 2001), and group B (diagnosed between 1 January and 31 December 2008) were phenotyped according to the Paris Classification. Phenotype at diagnosis and 2-year follow-up were then compared.

RESULTS

406 new cases of IBD were identified. The incidence was 2.5/100 000/year in 2001, 7.3 in 2008 and 5.6 in 2010, representing a significant increase in the number of new cases of Crohn's disease (CD) and ulcerative colitis (UC). There were 238 cases of CD; 129 of UC; and 39 of IBD unclassified. Comparing groups A and B, no differences were found in disease location at diagnosis or, for CD, in its behaviour.

CONCLUSIONS

There has been a substantial and sustained increase in the incidence of childhood UC and CD in Ireland over a relatively short period of time. However, disease phenotype at diagnosis has not changed. At 2 years follow-up, CD appears to progress less frequently than in some neighbouring countries. These variations remain unexplained. Prospective longitudinal studies will help to elucidate further the epidemiology of childhood IBD.

Rising incidence of pediatric inflammatory bowel disease in Scotland

BACKGROUND

An accurate indication of the changing incidence of pediatric inflammatory bowel disease (PIBD) within a population is useful in understanding concurrent etiological factors. We aimed to compare the current incidence and other demographic attributes of PIBD in the Scottish population to previous data.

METHODS

A national cohort of prospectively and retrospectively acquired incident cases of PIBD diagnosed less than 16 years old in pediatric services in Scotland was captured for the period 2003-2008; historical Scottish data were used for comparison (1990-1995). Age/sex-adjusted incidences were calculated and statistical comparisons made using Poisson regression.

RESULTS

During the 2003-2008 study period 436 patients were diagnosed with PIBD in Scotland, giving an adjusted incidence of 7.82/100,000/year. The incidence of Crohn's disease (CD) was 4.75/100,000/year, ulcerative colitis (UC) 2.06/100,000/year, and inflammatory bowel disease-unclassified (IBDU) 1.01/100,000/year. Compared with data from 1990-1995 when 260 IBD patients were diagnosed, significant rises in the incidence of IBD (from 4.45/100,000/year, P < 0.0001), CD (from 2.86/100,000/year, P < 0.0001), and UC (from 1.59/100,000/year, P = 0.023) were seen. There was also a significant reduction in the median age at IBD diagnosis from 12.7 years to 11.9 years between the periods (P = 0.003), with a continued male preponderance.

CONCLUSIONS

The number of Scottish children diagnosed with IBD continues to rise, with a statistically significant 76% increase since the mid-1990 s. Furthermore, PIBD is now being diagnosed at a younger age. The reason for this continued rise is not yet clear; however, new hypotheses regarding disease pathogenesis and other population trends may provide further insights in future years.

SOCS3 in immune regulation of inflammatory bowel disease and inflammatory bowel disease-related cancer

Inflammatory bowel disease (IBD) has unclear pathogenesis and it is related to the increasing risk of developing colorectal cancer (CRC). Recent studies have uncovered the molecular mechanism of intracellular signaling pathways of inflammatory cytokines such as tumor necrosis factor (TNF)-α, interferon (IFN)-γ and interleukin (IL)-6. The major transcription factors including STAT3 have been shown to play a major role in transmitting inflammatory cytokine signals to the nucleus. The suppressors of cytokine signaling (SOCS) 3 protein is the key physiological regulators of cytokine-mediated STAT3 signaling. As such it influences the development of inflammatory and malignant disorders like this associated with IBD. Here we review the complex function of SOCS3 in innate and adaptive immunity, different cell types (macrophages, neutrophils, dendritic cells, B cells, T cells and intestinal epithelial cells) and the role of SOCS3 on the pathogenesis of inflammatory bowel disease (IBD) and IBD-related cancer. Finally, we explore how this knowledge may open novel avenues for the rational treatment of IBD and IBD-related cancer.

[Inflammatory bowel diseases and inflammasome]

Inflammatory bowel disease (IBD), the most important entities being ulcerative colitis and Crohn's disease, are chronic, relapsing and remitting inflammatory conditions that result from chronic dysregulation of the mucosal immune system in the intestinal tract. Although the precise pathogenesis of IBD is still incompletely understood, increased levels of proinflammatory cytokines, including interleukin (IL)-1b, IL-18 and tumor necrosis factor-a, are detected in active IBD and correlate with the severity of inflammation, indicating that these cytokines may play a key role in the development of IBD. Recently, the intracellular nucleotide-binding oligomerization domain-like receptor (NLR) family members, including NLRP1, NLRP3, NLRC4 and NLRP6, are emerging as important regulators of intestinal homeostasis. Together, one of those aforementioned molecules or the DNA sensor absent in melanoma 2 (AIM2), apoptosis-associated speck-like protein containing 'a caspase recruitment domain (CARD)' (ASC) and caspase-1 form a large (> 700 kDa) multi-protein complex called the inflammasome. Stimulation with specific microbial and endogenous molecules triggers inflammasome assembly and caspase-1 activation. Activated caspase-1 leads to the secretion of proinflammatory cytokines, including IL-1b and IL-18, and the promotion of pyroptosis, a form of phagocyte cell death induced by bacterial pathogens, in an inflamed tissue. Therefore, inflammasomes are assumed to mediate host defense against microbial pathogens and gut homeostasis, so that their dysregulation might contribute to IBD pathogenesis. This review focuses on recent advances of the role of NLRP3 inflammasome signaling in IBD pathogenesis. Improving knowledge of the inflammasome could provide insights into potential therapeutic targets for patients with IBD.