IBD in 2012: Pathogenesis and management of IBD--thinking outside the box

Micro-RNAs -106a and -362-3p in Peripheral Blood of Inflammatory Bowel Disease Patients

Objective

MicroRNAs (miRNAs) can regulate various genes after binding to target mRNAs. Studies on Inflammatory Bowel Disease (IBD) in relation with miRNA are much less shown. The aim of the present study was to assess the expression patterns of microRNA 106a and microRNA 362-3p in peripheral blood samples of Inflammatory Bowel Disease (IBD) patients including Crohn's Disease(CD) and Ulcerative Colitis (UC).

Methods

This study consisted of 32 CD, 32 UC patients and 32 controls. The expression level of the micro-RNAs -106a and -362-3p was determined using reverse transcription and real-time RT-PCR.

Results

Our findings showed that MiR-106a and miR-362-3p are expressed at significantly higher levels in the peripheral blood from patients with CD and UC compared to controls. MiR-106a and miR-362-3p expression are also different in the peripheral blood of patients regarding the activity score of the disease. There were significant differences of miR362-3p in active UC relative to inactive UC.

Conclusion

Altogether our findings suggest that miR-106a and miR-363-3p can play an important role in the pathogenesis of IBD. The differences in expression of miR106a and miR362-3p in peripheral blood of the UC and CD patients in an active phase in comparison to inactive disease suggest that these miRNAs may be useful as potential biomarkers for diagnosis and monitoring the disease activity.

NOD2 Is Regulated By Mir-320 in Physiological Conditions but this Control Is Altered in Inflamed Tissues of Patients with Inflammatory Bowel Disease

BACKGROUND

Large evidence supports the role of microRNAs as new important inflammatory mediators by regulating both the adaptive and innate immunity. In the present study, we speculated that miR-320 controls NOD2 (nucleotide-binding oligomerization domain) expression, because it contains multiple binding sites in the 3'-untranslated region of the gene. NOD2, the first gene associated to increased susceptibility to Crohn's disease, is a cytosolic receptor that senses wall peptides of bacteria and promotes their clearance through initiation of a proinflammatory transcriptional program. This study aims at demonstrating that NOD2 is a target of miR-320 as well as investigating the role of inflammation in modulating the miR-320 control on NOD2 expression and analyzing miR-320 expression in intestinal biopsies of children with inflammatory bowel disease.

METHODS

The colonic adenocarcinoma cell line HT29 was used to assess the miR-320-mediated regulation of NOD2 expression. MiR-320 and NOD2 expression were analyzed in mucosal samples of 40 children with inflammatory bowel disease.

RESULTS

During inflammation, NOD2 expression is inversely correlated with miR-320 expression in vitro and ex vivo. Exogenous miR-320 transfection in HT29 cells leads to a significant decrease of NOD2 expression, whereas the miR-320 inhibitor transfection leads to increase of NOD2 expression, nuclear translocation of nuclear factor κB, and activation of downstream cytokines.

CONCLUSIONS

We show for the first time that NOD2 expression is under the control of miR-320. We also show in vitro and ex vivo that inflammation induces a decrease of miR-320 and the latter correlates negatively with NOD2 expression.

Fecal microbiota transplantation in inflammatory bowel disease: beyond the excitement

The purpose of this article is to perform a systematic review of the literature on the use of fecal microbiota transplantation (FMT) in inflammatory bowel disease (IBD).There is an increasing interest of both physicians and patients in assessing the possible role of the FMT in the treatment of IBD.Electronic and manual bibliographic searches were performed to identify original reports in which subjects with IBD were treated with FMT. Because of the scarcity of studies with adequate sample size, case series and case reports were also considered. A critical appraisal of the clinical research evidence on the effectiveness, safety, and other parameters related to FMT was made. Data extraction was independently performed by 2 reviewers.We found a total of 31 publications on the use of FMT in IBD. The majority were case reports or case series, whereas 8 publications reported data from open-label trials including a very less number of patients. A total of 133 patients with IBD were managed with FMT. Of these, 57 subjects (43%) had a Clostridium difficile infection. A resolution or reduction of symptoms was reported in 80 of 113 (71%) patients with evaluable IBD. Moreover, FMT does not seem to provide the same safety profile showed for non-IBD individuals with C difficile infection.The available evidence is limited and weak. FMT has the potential to be somehow of help in managing patients with IBD, but considerable further efforts are necessary to make this procedure a valid option for these subjects.

Advances in IBD genetics

IBD is a spectrum of chronic disorders that constitute an important health problem worldwide. The hunt for genetic determinants of disease onset and course has culminated in the Immunochip project, which has identified >160 loci containing IBD susceptibility genes. In this Review, we highlight how genetic association studies have informed our understanding of the pathogenesis of IBD by focusing research efforts on key pathways involved in innate immunity, autophagy, lymphocyte differentiation and chemotaxis. Several of these novel genetic markers and cellular pathways are promising candidates for patient stratification and therapeutic targeting.

The expanding role of therapeutic antibodies

Therapeutic antibodies have been used since the end of nineteenth century, but their use is progressively increased and recently, with the availability of monoclonal antibodies, they are successfully employed in a large disease spectrum, which transversally covers different fields of medicine. Hyperimmune polyclonal immune globulin has been used against infectious diseases, in a period in which anti-microbial drugs were not yet available, and it still maintains a relevant place in prophylaxis/therapy. Although immune globulin should be considered life-saving as replacement therapy in humoral immunodeficiencies, its place in the immune-modulating treatment is not usually first-choice, but it should be considered as support to standard approved treatments. Despite therapeutic monoclonal antibodies have been lastly introduced in therapy, their extreme potentiality is reflected by the large number of approved molecules, addressed toward different immunological targets and able to heavily influence the prognosis and quality of life of a wide range of different diseases.

Paediatric inflammatory bowel disease: a mechanistic approach to investigate exclusive enteral nutrition treatment

The inflammatory bowel diseases (IBD) include Crohn's disease (CD) and ulcerative colitis. The disease may present at any age although the peak of presentation is the second and third decades of life. The incidences of these diseases are increasing around the world with the age of presentation getting younger. At present CD is incurable with colectomy being the treatment for severe UC. Although several pharmacological approaches are used to modulate the inflammatory response in IBD, few lead to histological healing and most have side effects. An alternative approach is to use enteral formulae given exclusively (EEN) to treat IBD. EEN requires the consumption of an elemental or polymeric formula, with the exclusion of all other nutrients, for a period of up to 12 weeks. The introduction of EEN as a therapeutic option for IBD was through prudent observation; however, EEN has become an established and reliable option for the treatment of paediatric IBD. Despite this, the mechanisms through which EEN induces disease remission are unknown and remain hypothetical. This review will discuss recent research into EEN both describing clinical features of EEN therapy and discussing the most up-to-date understanding of the mechanisms through which EEN may be reducing intestinal inflammation and inducing disease remission.

Molecular mechanisms and cell targets of Th17 cells in the gastrointestinal tract: an innate sense of adaptivity

T-helper (TH) 17 activation is crucial for protective immune responses against bacteria and fungi at mucosal surfaces, but it can also be implicated in the pathogenesis of several autoimmune and chronic inflammatory diseases, such as inflammatory bowel diseases (IBD). Although rapid progress was made elucidating induction and functional heterogeneity of Th17 responses, the underlying molecular effects of Th17 response including the most relevant different cell targets of Th17 cytokines remain poorly understood. Cytokines produced by Th17 cells have broad effects on both hematopoietic and nonhematopoietic cells and can act in synergy with various inflammatory factors. In this review, we will focus on the effects of Th17-derived cytokines in the gastrointestinal tract and discuss how Th17 responses can affect both innate and adaptive immunity and may contribute to the pathogenesis of inflammatory GI processes.