Abstract
Background and Aims
Paediatric inflammatory bowel disease IBD is characterized by altered immunological and metabolic pathways. Metabolomics may therefore increase pathophysiological ...understanding and could develop into characterization of biomarkers for diagnosis and IBD treatment response. However, no uniform metabolomic profiles have been identified to date. This systematic review aimed to identify faecal metabolomic signatures in paediatric IBD vs controls, and to describe metabolites associated with disease activity and treatment response.
Methods
A literature search was performed in Embase, Medline, Web of Science and Cochrane Library. Studies assessing faecal metabolomics in paediatric patients < 18 years with IBD de novo, active, inactive with comparative groups IBD vs non-IBD; responders vs non-responders were included. The quality of included studies was assessed according to the Newcastle–Ottawa Scale.
Results
Nineteen studies were included 540 patients with IBD, 386 controls, assessing faecal short-chain fatty acids SCFA five studies, amino acids AA ten studies, bile acids BA eight studies and other metabolites nine studies using various methodologies. Significantly increased levels of AA particularly phenylalanine, primary BA and lower levels of secondary BA were described in paediatric IBD compared to controls. Faecal SCFA results varied across studies. Additionally, responders and non-responders to exclusive enteral nutrition and infliximab showed differences in baseline faecal metabolites based on BA, AA.
Conclusions
This systematic review provides evidence for distinct faecal metabolomic profiles in paediatric IBD. However, results varied across studies, possibly due to differences in study design and applied analytical techniques. Faecal metabolomics could provide more insight into host–microbial interactions in IBD, but further studies with standardized methodologies and reporting are needed.
Previous genome-wide association (GWA) studies typically focus on single-locus analysis, which may not have the power to detect the majority of genuinely associated loci. Here, we applied pathway ...analysis using Affymetrix SNP genotype data from the Wellcome Trust Case Control Consortium (WTCCC) and uncovered significant association between Crohn Disease (CD) and the IL12/IL23 pathway, harboring 20 genes (p = 8 × 10
−5). Interestingly, the pathway contains multiple genes (
IL12B and
JAK2) or homologs of genes (
STAT3 and
CCR6) that were recently identified as genuine susceptibility genes only through meta-analysis of several GWA studies. In addition, the pathway contains other susceptibility genes for CD, including
IL18R1,
JUN,
IL12RB1, and
TYK2, which do not reach genome-wide significance by single-marker association tests. The observed pathway-specific association signal was subsequently replicated in three additional GWA studies of European and African American ancestry generated on the Illumina HumanHap550 platform. Our study suggests that examination beyond individual SNP hits, by focusing on genetic networks and pathways, is important to unleashing the true power of GWA studies.
Background & Aims: Childhood-onset inflammatory bowel disease (IBD) might be etiologically different from adult-onset IBD. We analyzed disease phenotypes and progression of childhood-onset disease ...and compared them with characteristics of adult-onset disease in patients in Scotland. Methods: Anatomic locations and behaviors were assessed in 416 patients with childhood-onset (276 Crohn's disease CD, 99 ulcerative colitis UC, 41 IBD type unclassified IBDU diagnosed before seventeenth birthday) and 1297 patients with adult-onset (596 CD, 701 UC) IBD using the Montreal classification. Results: At the time of diagnosis in children, CD involved small bowel and colon (L3) in 51% (138/273), colon (L2) in 36%, and ileum (L1) in 6%; the upper gastrointestinal (GI) tract (L4) was also affected in 51%. In 39%, the anatomic extent increased within 2 years. Behavioral characteristics progressed; 24% of children developed stricturing or penetrating complications within 4 years (vs 9% at diagnosis; P < .0001; odds ratio OR, 3.32; 95% confidence interval CI, 1.86–5.92). Compared with adults, childhood-onset disease was characterized by a “panenteric” phenotype (ileocolonic plus upper GI L3+L4; 43% vs 3%; P < .0001; OR, 23.36; 95% CI, 13.45–40.59) with less isolated ileal (L1; 2% vs 31%; P < .0001; OR, 0.06; 95% CI, 0.03–0.12) or colonic disease (L2; 15% vs 36%; P < .0001; OR, 0.31; 95% CI, 0.21–0.46). UC was extensive in 82% of the children at diagnosis, versus 48% of adults ( P < .0001; OR, 5.08; 95% CI, 2.73–9.45); 46% of the children progressed to develop extensive colitis during follow-up. Forty-six percent of children with CD and 35% with UC required immunomodulatory therapy within 12 months of diagnosis. The median time to first surgery was longer in childhood-onset than adult-onset patients with CD (13.7 vs 7.8 years; P < .001); the reverse was true for UC. Conclusions: Childhood-onset IBD is characterized by extensive intestinal involvement and rapid early progression.
Although the exact pathophysiology remains unknown, the development of inflammatory bowel disease (IBD) is influenced by the interplay between genetics, the immune system, and environmental factors ...such as diet. The commonly used food additives, carrageenan and carboxymethylcellulose (CMC), are used to develop intestinal inflammation in animal models. These food additives are excluded from current dietary approaches to induce disease remission in Crohn's disease such as exclusive enteral nutrition (EEN) using a polymeric formula. By reviewing the existing scientific literature, this review aims to discuss the role that carrageenan and CMC may play in the development of IBD. Animal studies consistently report that carrageenan and CMC induce histopathological features that are typical of IBD while altering the microbiome, disrupting the intestinal epithelial barrier, inhibiting proteins that provide protection against microorganisms, and stimulating the elaboration of pro-inflammatory cytokines. Similar trials directly assessing the influence of carrageenan and CMC in humans are of course unethical to conduct, but recent studies of human epithelial cells and the human microbiome support the findings from animal studies. Carrageenan and CMC may trigger or magnify an inflammatory response in the human intestine but are unlikely to be identified as the sole environmental factor involved in the development of IBD or in disease recurrence after treatment. However, the widespread use of carrageenan and CMC in foods consumed by the pediatric population in a "Western" diet is on the rise alongside a corresponding increase in IBD incidence, and questions are being raised about the safety of frequent usage of these food additives. Therefore, further research is warranted to elucidate the role of carrageenan and CMC in intestinal inflammation, which may help identify novel nutritional strategies that hinder the development of the disease or prevent disease relapse post-EEN treatment.
Crohn's disease (CD), a form of inflammatory bowel disease (IBD), is thought to arise from a complex interaction of genetics, the gut microbiome, and environmental factors, such as diet. There is ...clear evidence that dietary intervention is successful in the treatment of CD-exclusive enteral nutrition (EEN) is able to induce remission in up to 80% of CD patients. While the mechanism of action of EEN is not clear, EEN is known to cause profound changes in the gut microbiome. Understanding how EEN modifies the gut microbiome to induce remission could provide insight into CD etiopathogenesis and aid the development of microbiome-targeted interventions to guide ongoing dietary therapy to sustain remission. This review includes current literature on changes in composition and function of the gut microbiome associated with EEN treatment in CD patients.
Background: As the microbiome plays an important role in instigating inflammation in ulcerative colitis (UC), strategies targeting the microbiome may offer an alternative therapeutic approach. The ...goal of the pilot trial was to evaluate the potential efficacy and feasibility of a novel UC exclusion diet (UCED) for clinical remission, as well as the potential of sequential antibiotics for diet-refractory patients to achieve remission without steroids. Methods: This was a prospective, single-arm, multicenter, open-label pilot study in patients aged 8–19, with pediatric UC activity index (PUCAI) scores >10 on stable maintenance therapy. Patients failing to enter remission (PUCAI < 10) on the diet could receive a 14-day course of amoxycillin, metronidazole and doxycycline (AMD), and were re-assessed on day 21. The primary endpoint was intention-to-treat (ITT) remission at week 6, with UCED as the only intervention. Results: Twenty-four UCED treatment courses were given to 23 eligible children (mean age: 15.3 ± 2.9 years). The median PUCAI decreased from 35 (30–40) at baseline to 12.5 (5–30) at week 6 (p = 0.001). Clinical remission with UCED alone was achieved in 9/24 (37.5%). The median fecal calprotectin declined from 818 (630.0–1880.0) μg/g at baseline to 592.0 (140.7–1555.0) μg/g at week 6 (p > 0.05). Eight patients received treatment with antibiotics after failing on the diet; 4/8 (50.0%) subsequently entered remission 3 weeks later. Conclusion: The UCED appears to be effective and feasible for the induction of remission in children with mild to moderate UC. The sequential use of UCED followed by antibiotic therapy needs to be evaluated as a microbiome-targeted, steroid-sparing strategy.
Introduction: Current therapies in pediatric Inflammatory Bowel Diseases (IBD) target the immune system and often fail to sustain long-term remission. There is a high need for development of ...alternative treatment strategies such as antibiotics in pediatric IBD.
Areas covered: This study systematically assessed efficacy and safety of antibiotics in pediatric IBD. CENTRAL, EMBASE, and Medline were searched for Randomized Controlled Trials (RCTs). Quality assessment was conducted with the Cochrane risk-of-bias tool.
Expert opinion: Two RCTs (n = 101, 4.4-18 years, 43% male) were included. Both studies had overall low risk of bias. In mild-to-moderate Crohn's disease, azithromycin+metronidazole (AZ+MET) (n = 35) compared to metronidazole (MET) alone (n = 38) did not induce a significantly different response (PCDAI drop ≥12.5 or remission) (p = 0.07). For induction of remission (PCDAI≤10), AZ+MET was more effective than MET (p = 0.025). In Acute Severe Colitis, mean 5-day-PUCAI was significantly lower in the antibiotic (vancomycin, amoxicillin, metronidazole, doxycycline)+intravenous-corticosteroids group (AB+IVCS) (n = 16) compared to IVCS alone (n=12) (p = 0.037), whereas remission (PUCAI<10) did not differ (p = 0.61). No significant drug-related adverse events were reported. Results of this systematic review of antibiotic use highlight the lack of evidence in pediatric IBD. More evidence is needed before widespread implementation in daily practice.
Inflammatory bowel disease (IBD) is a chronic, autoimmune disorder of the gastrointestinal tract with numerous genetic and environmental risk factors. Patients with Crohn's disease (CD) or ulcerative ...colitis (UC) often demonstrate marked disruptions of their gut microbiome. The intestinal microbiota is strongly influenced by diet. The association between the increasing incidence of IBD worldwide and increased consumption of a westernized diet suggests host nutrition may influence the progression or treatment of IBD via the microbiome. Several nutritional therapies have been studied for the treatment of CD and UC. While their mechanisms of action are only partially understood, existing studies do suggest that diet-driven changes in microbial composition and function underlie the diverse mechanisms of nutritional therapy. Despite existing therapies for IBD focusing heavily on immune suppression, nutrition is an important treatment option due to its superior safety profile, potentially low cost, and benefits for growth and development. These benefits are increasingly important to patients. In this review, we will describe the clinical efficacy of the different nutritional therapies that have been described for the treatment of CD and UC. We will also describe the effects of each nutritional therapy on the gut microbiome and summarize the strength of the literature with recommendations for the practicing clinician.
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