Rahul Kalla

MicroRNAs: new players in IBD

MicroRNAs (miRNAs) are small non-coding RNAs, 18–23 nucleotides long, which act as post-transcriptional regulators of gene expression. miRNAs are strongly implicated in the pathogenesis of many common diseases, including IBDs. This review aims to outline the history, biogenesis and regulation of miRNAs. The role of miRNAs in the development and regulation of the innate and adaptive immune system is discussed, with a particular focus on mechanisms pertinent to IBD and the potential translational applications.

Inflammatory Bowel Disease Associates with Proinflammatory Potential of the Immunoglobulin G Glycome

Background:Glycobiology is an underexplored research area in inflammatory bowel disease (IBD), and glycans are relevant to many etiological mechanisms described in IBD. Alterations in N-glycans attached to the immunoglobulin G (IgG) Fc fragment can affect molecular structure and immunological function. Recent genome-wide association studies reveal pleiotropy between IBD and IgG glycosylation. This study aims to explore IgG glycan changes in ulcerative colitis (UC) and Crohns disease (CD). Methods:IgG glycome composition in patients with UC (n = 507), CD (n = 287), and controls (n = 320) was analyzed by ultra performance liquid chromatography. Results:Statistically significant differences in IgG glycome composition between patients with UC or CD, compared with controls, were observed. Both UC and CD were associated with significantly decreased IgG galactosylation (digalactosylation, UC: odds ratio [OR] = 0.71; 95% confidence interval [CI], 0.5–0.9; P = 0.01; CD: OR = 0.41; CI, 0.3–0.6; P = 1.4 × 10−9) and significant decrease in the proportion of sialylated structures in CD (OR = 0.46, CI, 0.3–0.6, P = 8.4 × 10−8). Logistic regression models incorporating measured IgG glycan traits were able to distinguish UC and CD from controls (UC: P = 2.13 × 10−6 and CD: P = 2.20 × 10−16), with receiver–operator characteristic curves demonstrating better performance of the CD model (area under curve [AUC] = 0.77) over the UC model (AUC = 0.72) (P = 0.026). The ratio of the presence to absence of bisecting GlcNAc in monogalactosylated structures was increased in patients with UC undergoing colectomy compared with no colectomy (FDR-adjusted, P = 0.05). Conclusions:The observed differences indicate significantly increased inflammatory potential of IgG in IBD. Changes in IgG glycosylation may contribute to IBD pathogenesis and could alter monoclonal antibody therapeutic efficacy. IgG glycan profiles have translational potential as IBD biomarkers.

Thiopurine withdrawal during sustained clinical remission in inflammatory bowel disease: relapse and recapture rates, with predictive factors in 237 patients

Thiopurines (azathioprine and mercaptopurine) remain integral to most medical strategies for maintaining remission in Crohns disease (CD) and ulcerative colitis (UC). Indefinite use of these drugs is tempered by long‐term risks. While clinical relapse is noted frequently following drug withdrawal, there are few published data on predictive factors.

Crohn’s Disease

#### The bottom line Crohn’s disease is a chronic inflammatory disorder that can affect any part of the gastrointestinal tract. Although the disease most commonly presents at a young age, it can affect people of all ages. Patients often present with persistent diarrhoea, abdominal pain, and weight loss. Crohn’s disease has a global impact on patients’ education, work, and social and family life. High quality multidisciplinary care, of which primary care is a key aspect, can attenuate relapse, prevent long term complications, and improve quality of life. In this review we provide a practical approach to the diagnosis, management, and long term care of patients with Crohn’s disease. #### Sources and selection criteria We carried out an electronic search of PubMed, the Cochrane Library, and Ovid databases for articles using the term “Crohn’s disease”. We limited studies to those in adults and focused on high quality randomised control trials, meta-analyses, and systematic reviews. Crohn’s disease is an idiopathic, chronic relapsing immune mediated disease, the pathogenesis of which remains incompletely understood, although the condition is thought to arise from environmental priming and …

Serum Calprotectin: A Novel Diagnostic and Prognostic Marker in Inflammatory Bowel Diseases.

OBJECTIVES:There is an unmet need for novel blood-based biomarkers that offer timely and accurate diagnostic and prognostic testing in inflammatory bowel diseases (IBD). We aimed to investigate the diagnostic and prognostic utility of serum calprotectin (SC) in IBD.METHODS:A total of 171 patients (n=96 IBD, n=75 non-IBD) were prospectively recruited. A multi-biomarker model was derived using multivariable logistic regression analysis. Cox proportional hazards model was derived to assess the contribution of each variable to disease outcomes.RESULTS:SC correlated strongly with current biomarkers, including fecal calprotectin (FC) (n=50, ρ=0.50, P=1.6 × 10−4). SC was the strongest individual predictor of IBD diagnosis (odds ratio (OR): 9.37 (95% confidence interval (CI): 2.82–34.68), P=4.00 × 10−4) compared with other markers (C-reactive protein (CRP): OR 8.52 (95% CI: 2.75–28.63), P=2.80 × 10−4); albumin: OR 6.12 (95% CI: 1.82–22.16), P=0.004). In a subset of 50 patients with paired SC and FC, the area under receiver operating characteristic discriminating IBD from controls was better for FC than for SC (0.99, (95% CI 0.87–1.00) and 0.87 (95% CI:0.78–0.97), respectively; P=0.01). At follow-up (median 342 days; interquartile range: 88–563), SC predicted treatment escalation and/or surgery in IBD (hazard ratio (HR) 2.7, 95% CI: 1.1–4.9), in particular Crohn’s disease (CD) (HR 4.2, 95% CI 1.2–15.3). A model incorporating SC and either CRP or albumin has a positive likelihood ratio of 24.14 for IBD. At 1 year, our prognostic model can predict treatment escalation in IBD in 65% of cases (95% CI: 43–79%) and 80% (95% CI: 31–94%) in CD if ≥2 blood marker criteria are met.CONCLUSIONS:A diagnostic and prognostic model that combines SC and other blood-based biomarkers accurately predicts the inflammatory burden in IBD and has the potential to predict disease and its outcomes. Our data warrant further detailed exploration and validation in large multicenter cohorts.

Clinical utility of capsule endoscopy in patients with Crohn's disease and inflammatory bowel disease unclassified.

Background Although small bowel capsule endoscopy (SBCE) has developed an established role in Crohn’s disease (CD), there is paucity of data on impact of SBCE on subsequent management. We investigated the clinical utility of SBCE in patients with suspected and established CD and inflammatory bowel disease unclassified (IBDU). Materials and methods Patients referred routinely from 2003 to 2009 with a diagnosis of IBDU, suspected or established CD were identified retrospectively. Data were collected for indications and findings at SBCE with subsequent follow-up. Results A total of 315 patients were identified. There were n=265 referred for suspected CD (of which n=37 had a prior diagnosis of IBDU) and n=50 with established CD. SBCE was suggestive of CD in 17% of the suspected CD group, 43% in the IBDU group and 66% in the established CD patients. In the suspected CD cohort, an eventual diagnosis of CD was made in 12% (n=31) after a mean follow-up of 15 months (range 1–84), resulting in a change of management in 90% (n=28/31). In patients with IBDU, the diagnosis of CD was made in 38% (n=14) after an average follow-up of 19 months (±2). In patients with established CD, management was altered in 73% of patients after SBCE. Conclusion There was a low diagnostic yield in patients referred with suspected CD although a diagnosis at SBCE was predictive of a clinical diagnosis in the majority after a mean follow-up of 15 months. A diagnosis of CD was more likely in the IBDU and established CD cohort. SBCE diagnoses changed management in the majority of patients.

Biomarkers in search of Precision Medicine in IBD

The completion of the human genome project in 2003 represented a major scientific landmark, ushering in a new era with hopes and expectations of fresh insights into disease mechanisms and treatments. In inflammatory bowel disease (IBD), many important discoveries soon followed, notably the identification of >200 genetic susceptibility loci and characterization of the gut microbiome. As “big data”, driven by advances in technology, becomes increasingly available and affordable, individuals with IBD and clinicians alike yearn for tangible outcomes from the promise of “precision medicine”—precise diagnosis, monitoring, and treatment. Here, we provide a commentary on the prospects and challenges of precision medicine and biomarkers in IBD. We focus on the three key areas where precision IBD will have the most impact: (1) disease susceptibility, activity, and behavior; (2) prediction of drug response and adverse effects; and (3) identification of subphenotypic mechanisms to facilitate drug discovery and selection of new treatments in IBD.

Changes to Serum Sample Tube and Processing Methodology Does Not Cause Inter-Individual Variation in Automated Whole Serum N-Glycan Profiling in Health and Disease

Introduction Serum N-glycans have been identified as putative biomarkers for numerous diseases. The impact of different serum sample tubes and processing methods on N-glycan analysis has received relatively little attention. This study aimed to determine the effect of different sample tubes and processing methods on the whole serum N-glycan profile in both health and disease. A secondary objective was to describe a robot automated N-glycan release, labeling and cleanup process for use in a biomarker discovery system. Methods 25 patients with active and quiescent inflammatory bowel disease and controls had three different serum sample tubes taken at the same draw. Two different processing methods were used for three types of tube (with and without gel-separation medium). Samples were randomised and processed in a blinded fashion. Whole serum N-glycan release, 2-aminobenzamide labeling and cleanup was automated using a Hamilton Microlab STARlet Liquid Handling robot. Samples were analysed using a hydrophilic interaction liquid chromatography/ethylene bridged hybrid(BEH) column on an ultra-high performance liquid chromatography instrument. Data were analysed quantitatively by pairwise correlation and hierarchical clustering using the area under each chromatogram peak. Qualitatively, a blinded assessor attempted to match chromatograms to each individual. Results There was small intra-individual variation in serum N-glycan profiles from samples collected using different sample processing methods. Intra-individual correlation coefficients were between 0.99 and 1. Unsupervised hierarchical clustering and principal coordinate analyses accurately matched samples from the same individual. Qualitative analysis demonstrated good chromatogram overlay and a blinded assessor was able to accurately match individuals based on chromatogram profile, regardless of disease status. Conclusions The three different serum sample tubes processed using the described methods cause minimal inter-individual variation in serum whole N-glycan profile when processed using an automated workstream. This has important implications for N-glycan biomarker discovery studies using different serum processing standard operating procedures.

How to Apply for and Secure EU Funding for Collaborative IBD Research Projects

The European Union offers opportunities for high-level of funding of collaborative European research. Calls are regularly published: after the end of the FP7 funding programme the new round of Horizon 2020 calls started in 2015. Several topics are relevant to inflammatory bowel disease (IBD) challenges, including chronic disease management, biomarker discovery and new treatments developments. The aim of this Viewpoint article is to describe the new Horizon 2020 instrument and the project submission procedures, and to highlight these through the description of tips and tricks, taking advantage of four examples of successful projects in the field of IBD: the SADEL, IBD-BIOM, IBD Character and BIOCYCLE projects.

Small Bowel Capsule Endoscopy

Although optical technology in the gastrointestinal tract has much improved in the last decade, image quality is only as good as the preparation achieved. As current capsule technology does not allow suctioning or flushing of fluid from the surface of the small bowel mucosa, there is consequently a greater imperative for adequate preparation to optimise detection of any potential lesion by the capsule endoscope.