Polymeric diet alone versus corticosteroids in the treatment of active pediatric Crohn's disease: a randomized controlled open-label trial

Pre-operative total parenteral nutrition improves post-operative outcomes in a subset of Crohn's disease patients undergoing major abdominal surgery

Background

Despite major advances in the medical management of Crohn’s disease (CD), a significant proportion of patients will require surgery within 5 years of diagnosis. Malnutrition is an independent risk factor for adverse post-operative outcomes following gastrointestinal surgery. Data on the value of pre-operative total parenteral nutrition (TPN) in CD patients are mixed and there is a paucity of data in the biologic era. We aimed to define the role of pre-operative TPN in this population.

Methods

This was a retrospective cohort study conducted at a tertiary referral center. CD patients who underwent major abdominal surgery were identified. Patients receiving pre-operative TPN were compared to controls. We compared the incidence of 30-day infectious and non-infectious post-operative complications between the two groups.

Results

A total of 144 CD patients who underwent major abdominal surgery between March 2007 and March 2017 were included. Fifty-five patients who received pre-operative TPN were compared to 89 controls. Twenty-one (14.6%) patients developed infectious complications (18.2% in TPN group vs 12.3% in non-TPN group, P = 0.34) and 23 (15.9%) developed non-infectious complications (14.5% in TPN group vs 16.9% in non-TPN group, P = 0.71). In a multivariate analysis, controlling for differences in baseline disease severity and malnutrition between groups, patients receiving pre-operative TPN for ≥60 days had significantly lower odds of developing non-infectious complications (odds ratio 0.07, 95% confidence interval: 0.01–0.80, P = 0.03). Weight loss of >10% in the past 6 months was a significant predictor of post-operative complications.

Conclusions

In a subset of malnourished CD patients, TPN is safe and allows comparable operative outcomes to controls. Pre-operative TPN for ≥60 days reduced post-operative non-infectious complications without associated increase in infectious complications.

Evolving role of diet in the pathogenesis and treatment of inflammatory bowel diseases

Recent advances in basic and clinical science over the last 3 years have dramatically altered our appreciation of the role of diet in inflammatory bowel diseases (IBD). The marked increase in incidence of these diseases along with the important role of non-genetic susceptibility among patients with IBD has highlighted that these diseases have a strong environmental component. Progress in the field of microbiome and IBD has demonstrated that microbiome appears to play an important role in pathogenesis, and that diet may in turn impact the composition and functionality of the microbiome. Uncontrolled clinical studies have demonstrated that various dietary therapies such as exclusive enteral nutrition and newly developed exclusion diets might be potent tools for induction of remission at disease onset, for patients failing biologic therapy, as a treatment for disease complications and in reducing the need for surgery. We review these advances from bench to bedside, along with the need for better clinical trials to support these interventions.

The role of diet in the aetiopathogenesis of inflammatory bowel disease

Crohn's disease and ulcerative colitis, collectively known as IBD, are chronic inflammatory disorders of the gastrointestinal tract. Although the aetiopathogenesis of IBD is largely unknown, it is widely thought that diet has a crucial role in the development and progression of IBD. Indeed, epidemiological and genetic association studies have identified a number of promising dietary and genetic risk factors for IBD. These preliminary studies have led to major interest in investigating the complex interaction between diet, host genetics, the gut microbiota and immune function in the pathogenesis of IBD. In this Review, we discuss the recent epidemiological, gene-environment interaction, microbiome and animal studies that have explored the relationship between diet and the risk of IBD. In addition, we highlight the limitations of these prior studies, in part by explaining their contradictory findings, and review future directions.

Treatment of Active Crohn's Disease with Exclusive and Partial Enteral Nutrition: A Pilot Study in Adults

BACKGROUND AND AIM

Enteral nutrition (EN) is not commonly used for the treatment of adults with active Crohn's disease (CD), despite patient interest in nutrition-based alternatives to corticosteroids and evidence of efficacy in paediatric CD. The aim of this study was to assess the impact of 2 different EN regimens on disease symptoms, nutrition and inflammatory markers in young adults with active CD.

METHODS

A prospective non-randomized pilot study of adults aged 16-40 years with active CD on endoscopy or imaging was undertaken. Patients were sequentially recruited to use 2 weeks of exclusive EN (EEN) followed by either 6 weeks of EEN or partial EN (PEN) with usual diet. Assessments of disease symptoms, nutrition and inflammatory markers were undertaken at baseline and throughout the treatment.

RESULTS

Thirty-eight patients with active disease were recruited. Thirty-two (84$) patients completed 2 weeks of EEN and had significant improvements in disease symptoms (p = 0.003), serum c-reactive protein (CRP; p = 0.005), insulin-like growth factor-1 (p = 0.006) and faecal calprotectin (FC; p = 0.028). During the following 6 weeks, 21 patients continued EEN (14 [67$] completed treatment) and 11 patients used PEN (9 [82$] completed treatment). Initial improvements in symptoms, CRP and nutrition markers were sustained over the next 6 weeks on both treatments. FC non-significantly increased in 5 out of 9 patients who used PEN and at week 8 FC was greater than 500 µg/g in 9 out of 14 and 7 out of 9 patients who used exclusive or PEN respectively. There was no significant difference in clinical outcomes between the 2 groups at week 8.

CONCLUSION

Two weeks of EEN significantly improved disease symptoms, nutrition and inflammatory markers. Further treatment with exclusive or PEN maintained initial improvements.

Using Quality Improvement to Increase Utilization of Enteral Therapy in Pediatric Crohn Disease: Results and Outcomes

INTRODUCTION

Exclusive enteral nutrition (EEN) for induction of remission in children with Crohn disease (CD) is recommended as first-line therapy, but underutilized in the United States related to real and perceived barriers. We hypothesized that quality improvement (QI) methodology could increase use of EEN.

METHODS

We developed, implemented, and revised an algorithm and a set of tools to facilitate use of EEN. Through a series of Plan Do Study Act cycles, the approach was modified to overcome provider and patient/family barriers. The primary outcome, the percentage of newly diagnosed CD patients who receive EEN per month between July 2013 and October 2015, assessed using statistical process control. Secondary outcomes, including the short pediatric Crohn disease activity index (sPCDAI), body mass index (BMI) z score, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), albumin, and hemoglobin were compared before and after EEN.

RESULTS

Among patients newly diagnosed with CD, 73 patients initiated EEN and were included (mean age 12.7 ± 2.9 years, 49% girls, 86% white). Rates of utilization of EEN increased significantly from a baseline of <5% to an average of approximately 50%. Of the 73 patients who started EEN, 37 (50%) completed a minimum of 8 weeks. Of those completing therapy, 25 (71%) achieved remission, with a significant reduction of sPCDAI (33.6 ± 14.4 to 10.7 ± 12.3, P < 0.0001) CONCLUSIONS:: Use of QI methodology to systematically implement tools designed to improve utilization was effective in increasing the use of EEN. Among those completing therapy, EEN was effective in inducing remission.

Efficacy predictors of a 2-month exclusive enteral nutrition for inducing remission of active Crohn's disease

In order to identify the factors that could predict the efficacy of exclusive enteral nutrition (EEN) in inducing remission of active CD. Baseline clinical and laboratory covariates were correlated with the outcome (clinical remission) of EEN in active CD (CDAI ≥150) by both univariable and multivariable analyses. A total of 67 from a consecutive of 136 active CD patients were enrolled. L4b (from treitz ligament to distal 1/3 ileum) involvement was negatively and high serum albumin (≥35 g/L) was positively associated with clinical remission (OR: 0.14, OR: 14.71). In conclusion, L4b sparing and high serum albumin might predict a favorable outcome of EEN in active CD (ClinicalTrials.gov ID: NCT 02942511).

Nutrition in Pediatric Inflammatory Bowel Disease: A Position Paper on Behalf of the Porto Inflammatory Bowel Disease Group of the European Society of Pediatric Gastroenterology, Hepatology and Nutrition

BACKGROUND AND AIMS

A growing body of evidence supports the need for detailed attention to nutrition and diet in children with inflammatory bowel disease (IBD). We aimed to define the steps in instituting dietary or nutritional management in light of the current evidence and to offer a useful and practical guide to physicians and dieticians involved in the care of pediatric IBD patients.

METHODS

A group of 20 experts in pediatric IBD participated in an iterative consensus process including 2 face-to-face meetings, following an open call to Nutrition Committee of the European Society of Pediatric Gastroenterology, Hepatology and Nutrition Porto, IBD Interest, and Nutrition Committee. A list of 41 predefined questions was addressed by working subgroups based on a systematic review of the literature.

RESULTS

A total of 53 formal recommendations and 47 practice points were endorsed with a consensus rate of at least 80% on the following topics: nutritional assessment; macronutrients needs; trace elements, minerals, and vitamins; nutrition as a primary therapy of pediatric IBD; probiotics and prebiotics; specific dietary restrictions; and dietary compounds and the risk of IBD.

CONCLUSIONS

This position paper represents a useful guide to help the clinicians in the management of nutrition issues in children with IBD.

Enteral nutritional therapy for induction of remission in Crohn's disease

BACKGROUND

Corticosteroids are often preferred over enteral nutrition (EN) as induction therapy for Crohn's disease (CD). Prior meta-analyses suggest that corticosteroids are superior to EN for induction of remission in CD. Treatment failures in EN trials are often due to poor compliance, with dropouts frequently due to poor acceptance of a nasogastric tube and unpalatable formulations. This systematic review is an update of a previously published Cochrane review.

OBJECTIVES

To evaluate the effectiveness and safety of exclusive EN as primary therapy to induce remission in CD and to examine the importance of formula composition on effectiveness.

SEARCH METHODS

We searched MEDLINE, Embase and CENTRAL from inception to 5 July 2017. We also searched references of retrieved articles and conference abstracts.

SELECTION CRITERIA

Randomized controlled trials involving patients with active CD were considered for inclusion. Studies comparing one type of EN to another type of EN or conventional corticosteroids were selected for review.

DATA COLLECTION AND ANALYSIS

Data were extracted independently by at least two authors. The primary outcome was clinical remission. Secondary outcomes included adverse events, serious adverse events and withdrawal due to adverse events. For dichotomous outcomes, we calculated the risk ratio (RR) and 95% confidence interval (CI). A random-effects model was used to pool data. We performed intention-to-treat and per-protocol analyses for the primary outcome. Heterogeneity was explored using the Chi² and I² statistics. The studies were separated into two comparisons: one EN formulation compared to another EN formulation and EN compared to corticosteroids. Subgroup analyses were based on formula composition and age. Sensitivity analyses included abstract publications and poor quality studies. We used the Cochrane risk of bias tool to assess study quality. We used the GRADE criteria to assess the overall quality of the evidence supporting the primary outcome and selected secondary outcomes.

MAIN RESULTS

Twenty-seven studies (1,011 participants) were included. Three studies were rated as low risk of bias. Seven studies were rated as high risk of bias and 17 were rated as unclear risk of bias due to insufficient information. Seventeen trials compared different formulations of EN, 13 studies compared one or more elemental formulas to a non-elemental formula, three studies compared EN diets of similar protein composition but different fat composition, and one study compared non-elemental diets differing in glutamine enrichment. Meta-analysis of 11 trials (378 participants) demonstrated no difference in remission rates. Sixty-four per cent (134/210) of patients in the elemental group achieved remission compared to 62% (105/168) of patients in the non-elemental group (RR 1.02, 95% CI 0.88 to 1.18; GRADE very low quality). A per-protocol analysis (346 participants) produced similar results (RR 1.04, 95% CI 0.91 to 1.18). Subgroup analyses performed to evaluate the different types of elemental and non-elemental diets (elemental, semi-elemental and polymeric) showed no differences in remission rates. An analysis of 7 trials including 209 patients treated with EN formulas of differing fat content (low fat: < 20 g/1000 kCal versus high fat: > 20 g/1000 kCal) demonstrated no difference in remission rates (RR 1.03; 95% CI 0.85 to 1.26). Very low fat content (< 3 g/1000 kCal) and very low long chain triglycerides demonstrated higher remission rates than higher content EN formulas. There was no difference between elemental and non-elemental diets in adverse event rates (RR 1.00, 95% CI 0.63 to 1.60; GRADE very low quality), or withdrawals due to adverse events (RR 1.29, 95% CI 0.80 to 2.09; GRADE very low quality). Common adverse events included nausea, vomiting, diarrhea and bloating.Ten trials compared EN to steroid therapy. Meta-analysis of eight trials (223 participants) demonstrated no difference in remission rates between EN and steroids. Fifty per cent (111/223) of patients in the EN group achieved remission compared to 72% (133/186) of patients in the steroid group (RR 0.77, 95% CI 0.58 to 1.03; GRADE very low quality). Subgroup analysis by age showed a difference in remission rates for adults but not for children. In adults 45% (87/194) of EN patients achieved remission compared to 73% (116/158) of steroid patients (RR 0.65, 95% CI 0.52 to 0.82; GRADE very low quality). In children, 83% (24/29) of EN patients achieved remission compared to 61% (17/28) of steroid patients (RR 1.35, 95% CI 0.92 to 1.97; GRADE very low quality). A per-protocol analysis produced similar results (RR 0.93, 95% CI 0.75 to 1.14). The per-protocol subgroup analysis showed a difference in remission rates for both adults (RR 0.82, 95% CI 0.70 to 0.95) and children (RR 1.43, 95% CI 1.03 to 1.97). There was no difference in adverse event rates (RR 1.39, 95% CI 0.62 to 3.11; GRADE very low quality). However, patients on EN were more likely to withdraw due to adverse events than those on steroid therapy (RR 2.95, 95% CI 1.02 to 8.48; GRADE very low quality). Common adverse events reported in the EN group included heartburn, flatulence, diarrhea and vomiting, and for steroid therapy acne, moon facies, hyperglycemia, muscle weakness and hypoglycemia. The most common reason for withdrawal was inability to tolerate the EN diet.

AUTHORS' CONCLUSIONS

Very low quality evidence suggests that corticosteroid therapy may be more effective than EN for induction of clinical remission in adults with active CD. Very low quality evidence also suggests that EN may be more effective than steroids for induction of remission in children with active CD. Protein composition does not appear to influence the effectiveness of EN for the treatment of active CD. EN should be considered in pediatric CD patients or in adult patients who can comply with nasogastric tube feeding or perceive the formulations to be palatable, or when steroid side effects are not tolerated or better avoided. Further research is required to confirm the superiority of corticosteroids over EN in adults. Further research is required to confirm the benefit of EN in children. More effort from industry should be taken to develop palatable polymeric formulations that can be delivered without use of a nasogastric tube as this may lead to increased patient adherence with this therapy.

Reasoning Beyond the Potential Use of Exclusive Enteral Nutrition and Other Specified Diets in Children With Ulcerative Colitis

The incidence of inflammatory bowel disease (IBD) is steadily on the rise in Western and in developing countries paralleling the increase of westernized diets, characterized by high protein and fat as well as excessive sugar intake, with less vegetables and fiber. Furthermore, nutrition is involved in several aspects of pediatric IBD, ranging from disease etiology to induction and maintenance of remission of disease. Exclusive enteral nutrition (EEN) has been shown to induce remission, including in patients with isolated colonic disease, and leads to mucosal healing in Crohn disease. One hypothesis for the beneficial effect of this modality is exclusion of dietary components thought to cause dysbiosis or impair innate immune mechanisms such as the mucous layer, intestinal permeability or colonization and adherence with adherent-invasive Escherichia coli. Although there is not yet definitive data illustrating a role for EEN in the management of active ulcerative colitis (UC), there are several lines of evidence that illustrate that dietary interventions may be helpful. In particular, the key mechanisms of the activity of EEN (namely, changes in the intestinal microflora in Crohn disease) are likely also relevant to UC. Furthermore, the use of EEN in pediatric UC patients may add to a better bone health. Prospective studies are now required to evaluate the role of EEN in UC in children.

Differences in Outcomes Over Time With Exclusive Enteral Nutrition Compared With Steroids in Children With Mild to Moderate Crohn's Disease: Results From the GROWTH CD Study

BACKGROUND

Exclusive enteral nutrition [EEN] and corticosteroids [CS] induce similar rates of remission in mild to moderate paediatric Crohn's disease [CD], but differ with regard to mucosal healing. Our goal was to evaluate if EEN at diagnosis was superior to CS for improving long-term outcomes.

METHODS

We prospectively followed newly diagnosed children aged < 17 years, with mild to moderate CD at baseline, for 2 years in the GROWTH CD study. Patients were evaluated at baseline and at 8, 12, 78, and 104 weeks. Remission, relapses, complications [fibrostenotic disease, penetrating disease, and active perianal disease] and growth were recorded throughout the study. A propensity score analysis was performed.

RESULTS

A total of 147 children [mean age 12.9 ± 3.2 years], treated by EEN [n = 60] or CS [n = 87] were included. New complications developed in 13.7% of CS [12/87] versus 11.6% of EEN [7/60], p = 0.29. Remission was achieved in 41/87 [47%] in CS and 38/60 [63%] EEN, p = 0.036. Median time to relapse did not differ [14.4 ± 1 months with CS, 16.05 ± 1.1 EEN, p = 0.28]. Mean height Z scores decreased from Week 0 to Week 78 with CS [-0.34 ± 1.1 to -0.51 ± 1.2, p = 0.01], but not with EEN [-0.32 ± 1.1 to -0.22 ± 0.9, p = 0.56]. In a propensity score analysis, EEN was superior to CS for inducing remission [p = 0.05] and trended to superiority for height Z score [p = 0.055].

CONCLUSIONS

Use of EEN was associated with higher remission rates and a trend toward better growth but with similar relapse and complication rates in new-onset mild to moderate paediatric CD.

Enteral Nutrition for Pediatric Crohn's Disease: An Underutilized Therapy

Enteral nutrition (EN) for the treatment of Crohn's disease (CD) involves administration of a liquid nutrition product, administered orally or through tube feeding, while excluding typical dietary components. It is a safe and effective, but largely underused, therapy in the United States as a treatment for CD. EN is a particularly attractive option for pediatric CD as it avoids side effects of corticosteroids, improves growth, and may have a higher likelihood of achieving mucosal healing than some traditional medications. However, there are multiple real and perceived barriers to its use among providers. A comprehensive approach to addressing these barriers to EN may result in its increased use. This paper reviews the literature on the efficacy of EN, methods of utilization, and potential barriers and solutions to those barriers.

Exclusive enteral nutrition in Crohn's disease: Evidence and practicalities

Exclusive enteral nutrition (EEN) is the first line therapy for paediatric Crohn's disease, providing a complete nutritional feed whilst simultaneously inducing remission in up to 80% of cases. The effect of EEN on systemic/local intestinal immune function and subsequent inflammation (including barrier permeability, direct anti-inflammatory effects and cytokine signalling pathways), alongside changes in the microbiome (specific species and broad taxonomic shifts, functional changes) are becoming clearer, however the exact mechanism for induction of remission in Crohn's disease remains uncertain. The evidence of efficacy in paediatric Crohn's disease is strong, with selected adult populations also benefiting from EEN. However despite recommendations from all major societies (ECCO, ESPGHAN, NASPGHAN and ESPEN) first-line use of EEN is varied and Europe/Australasia/Canada show significantly more routine use than other parts of North America. Growth and nutritional status are significantly improved with EEN compared to corticosteroids but long-term outcomes are sparse. This review discusses the evidence underlying the use of EEN, highlighting the mechanisms thought to underlie how EEN induces remission in Crohn's disease, when and how to use EEN, including practical issues in both paediatric and adult practice (formulation, compliance, volumes and administration), and summarises the ongoing research priorities.

TH17 cell plasticity: The role of dendritic cells and molecular mechanisms

Upon interaction with dendritic cells (DCs), naïve CD4 T cells differentiate into distinct subsets and orchestrate the development of a physiological immune response. When uncontrolled by cellular and molecular mechanisms, CD4 T cells can also lead to immune mediated inflammatory diseases (IMIDs). Initially, these distinct CD4 T-cell subsets were defined according to the expression of a limited number of cytokines. Later it was revealed that CD4 T cells can acquire much more complex functional phenotypes than previously thought. Experimental data showed that the CD4 T-cell subset T_H17 can secrete IFN-γ and IL-4, which are signature molecules of other T-cell subsets. Furthermore, some T_H17 cells can also explore an anti-inflammatory fate and participate in the resolution of the immune response. A more flexible theory has therefore evolved with the scope to better represent the plastic biology of CD4 T cells. In this context, several aspects still remain unclear. The goal of this review is to discuss the role of extrinsic and intrinsic cellular and molecular mechanisms, which can drive the plasticity of T_H17 cells. In particular, we will outline the role of DCs and the function of transcriptional factors in shaping the fate of T_H17 cells towards either a pathogenic or a regulatory phenotype. Finally, we will discuss whether T_H17 cell plasticity could be a target for new therapies for IMIDs. We indeed envision that when the cellular and molecular mechanisms controlling T_H17 plasticity are known, new therapies, which aim to reset the immune system, will be developed. This will be achieved by either selectively depleting only the pathogenic T_H17 cells or, if possible, re converting these cells from pathogenic to regulatory. This will overcome the challenge posed by the immune suppressive side effects caused by the current therapies, which impair the function of CD4 cells or delete all of them, to the detriment of the patient.

Enteral Nutrition in the Management of Crohn's Disease: Reviewing Mechanisms of Actions and Highlighting Potential Venues for Enhancing the Efficacy

Crohn's disease (CD) is a chronic condition that affects the gut and has adverse effects on growth and development. There is a global increase in the incidence and prevalence rates, and several factors are believed to contribute to this rise, including dietary habits. In contrast, the use of enteral nutrition (EN) as an exclusive source of nutrition is increasingly becoming the preferred induction treatment of pediatric CD patients in part to address the nutrition complications. However, EN therapy is considered less effective in adults with CD. A better understanding of the molecular mechanisms of enteral therapy will help improve the clinical management of CD. It is increasingly becoming evident that the therapeutic utility of EN is in part due to the reversal of the microbial changes and the direct immunomodulatory effects. Moreover, there is a potential tendency for enhancing the efficacy of EN therapy by improving the palatability of the given formulas and, more important, by magnifying the anti-inflammatory properties. Recent observations have shown that the immunomodulatory effects of EN are mediated at least in part by blocking nuclear factor-κB. Furthermore, it is likely that several ingredients of EN contribute to this activity, in particular glutamine and arginine amino acids. In addition, manipulating the composition of EN therapy by altering concentrations of the key ingredients is found to have the potential for more efficient therapy. In this review, the underlying mechanisms of EN actions will be discussed further with a focus on the potential methods for enhancing the efficacy.

Nutritional support in paediatric Crohn's disease: outcome at 12 months

AIM

Paediatric Crohn's disease (CD) is associated with growth delay and poor nutritional status. Maintenance enteral nutrition (MEN) supplementation is a potential adjunct to improve growth/prolong remission.

METHODS

Newly diagnosed CD patients were identified. Anthropometry, treatments and outcomes were collected for 12 months following diagnosis. Data are presented as medians.

RESULTS

A total of 102 patients were identified (age = 13 years, 76% male), 58 (57%) completed exclusive enteral nutrition (EEN) as induction therapy, and 77 (75%) entered clinical remission. Following induction, 58 (57%) of all patients continued MEN and 44 (43%) consumed normal diet (ND). BMI Z-score increased (diagnosis-12 months) for EEN (-1.41 to -0.21 (p = <0.0001)) and steroid groups (-0.97 to -0.11 (p = 0.001)). BMI Z-score increased (post induction - 12 months) for MEN (-0.62 to -0.44 (p = 0.04)) but not ND (-0.33 to -0.4 (p = 0.79)). Height Z-score did not increase for any treatment group over 12 months. MEN and ND group relapse rates were similar at six months, MEN = 21/58 (36%); ND = 21/44 (48%) (p = 0.24) and 12 months, MEN = 24/58 (41%); ND = 13/44 (30%) (p = 0.22). Fewer patients treated with EEN then MEN relapsed less than six months, 14 of 43 (33%), compared to patients treated with steroids then ND 16/29 (55%) (p = 0.09).

CONCLUSION

BMI Z-score increased but height Z-score remained unchanged over 12 months for the MEN group. Use of MEN was not associated with prolonged time to relapse. Prospective studies are required to examine the utility of MEN.

Gut microbiome: a new player in gastrointestinal disease

The gastrointestinal (GI) tract harbors a diverse and host-specific gut microbial community. Whereas host-microbe interactions are based on homeostasis and mutualism, the microbiome also contributes to disease development. In this review, we summarize recent findings connecting the GI microbiome with GI disease. Starting with a description of biochemical factors shaping microbial compositions in each gut segment along the longitudinal axis, improved histological techniques enabling high resolution visualization of the spatial microbiome structure are highlighted. Subsequently, inflammatory and neoplastic diseases of the esophagus, stomach, and small and large intestines are discussed and the respective changes in microbiome compositions summarized. Finally, approaches aiming to restore disturbed microbiome compositions thereby promoting health are discussed.

Preoperative optimization of patients with inflammatory bowel disease undergoing gastrointestinal surgery: a systematic review

PURPOSE

Surgical management of inflammatory bowel disease (IBD) is a challenging task. The aim of preoperative optimization (PO) is to decrease the risk of complications and reduce the length of postoperative stay. The aim of this study was to review and grade the available evidence, attain clear recommendations, and point out potential future research.

METHODS

Studies were identified from electronic databases (PubMed, Embase, and Cochrane Library) and scanning reference lists in relevant papers. English-written studies examining PO in adult patients with IBD were included. Eight PO factors were investigated.

RESULTS

Management of IBD is a multidisciplinary task. Steroid withdrawal is recommended while steroid stress dose is not recommended. Thiopurines appear to be safe, but it may be prudent to plan the procedure remotely from the last dose of an anti-TNF agent. Nutritional risk screening is recommended to unveil and correct any malnutrition. Thrombosis prophylaxis prior to surgery is well supported by evidence while extended 4-week prophylaxis needs further research. Percutaneous ultrasound or CT-guided drainage for intra-abdominal abscesses is recommended, but it is unclear for how long supplementary antibiotics (ABs) should be used. Oral AB 24 h prior to open surgery might improve outcome if given as complementary to IV perioperative AB. Mechanical bowel preparation is not supported by evidence. Comorbidities must be treated accordingly prior to surgical intervention. Smoking cessation can be beneficial for wound healing.

CONCLUSION

Multimodel PO intervention in IBD patients is recommended.

Medical management of pediatric inflammatory bowel disease

Inflammatory bowel diseases (IBD) are chronic autoimmune conditions of the gut affecting both pediatric and adult patients. Medical therapy is often successful at inducing and maintaining remission and preventing disease complications. The mainstays of treatment are medications and other therapies that reduce inflammation and suppress the overactive immune system. Here we review current medical therapies for pediatric IBD, discuss future therapeutics, and present current treatment goals and approaches.

Dietary Therapies in Pediatric Inflammatory Bowel Disease: An Evolving Inflammatory Bowel Disease Paradigm

Nutrition has long been recognized as a critical component in the treatment of pediatric inflammatory bowel disease (IBD). Formerly, nutritional interventions have focused on targeting improved weight gain and linear growth, as well as correction of micronutrient deficiencies. Recently, there has been growing interest and study of dietary interventions for induction and maintenance of remission. In addition to exclusive enteral nutrition, successes have been achieved with specific exclusion diets. This article evaluates current literature regarding the role of diet and nutrition in pathogenesis of disease, as well as the role of diet as primary therapy for pediatric IBD.

Recipe for IBD: can we use food to control inflammatory bowel disease?

The mucosal immune system and the microbiota in the intestinal tract have recently been shown to play a key role in the pathogenesis of inflammatory bowel disease (IBD). Both of these can be influenced by food. Thus, we propose dietary intervention as a therapeutic option for IBD. In this review, we discuss the interaction of the intestinal mucosal immune system and the intestinal microbiota in the context of IBD. In addition, we discuss the impact of food components on immune responses in IBD. Finally, we address the current evidence of how this interaction (i.e., immune system-microbiota) can be modulated by food components, pre/probiotics, and fecal microbiota transplantation (FMT) and how these approaches can support intestinal homeostasis. By gathering the vast amount of literature available on the impact of food on IBD, we aim to distinguish between scientifically sound data and theories, which have not been included in this review.

Preoperative Nutritional Optimization for Crohn's Disease Patients Can Improve Surgical Outcome

BACKGROUND

Preoperative preparation of patients with Crohn's disease is challenging and there are no specific guidelines regarding nutritional support. The aim of this study was to assess whether preoperative nutritional support influenced the postoperative outcome.

METHODS

A retrospective, cohort study including all Crohn's disease patients who underwent abdominal surgery between 2008 and 2014 was conducted. Patients' characteristics and clinical and surgical data were recorded and analyzed.

RESULTS

Eighty-seven patients were included in the study. Thirty-seven patients (42.5%) received preoperative nutritional support (mean albumin level 3.14 vs. 3.5 mg/dL in the non-optimized group; p < 0.02) to optimize their nutritional status prior to surgery. Preoperative albumin level, after adequate nutritional preparation, was similar between the 2 groups. The 2 groups differ neither in demographic and surgical data, overall post-op complication (p = 0.85), Clavien-Dindo score (p = 0.42), and length of stay (p = 0.1). Readmission rate was higher in the non-optimized group (p = 0.047).

CONCLUSION

Nutritional support can minimize postoperative complications in patients with low albumin levels. Nutritional status should be optimized in order to avoid hazardous complications.

Exclusive Enteral Nutrition Induces Remission in Pediatric Crohn's Disease via Modulation of the Gut Microbiota

Exclusive enteral nutrition (EEN) has been proven to be effective and safe in treating pediatric Crohn's disease (CD). EEN induces pediatric CD remission possibly through three pathways: (1) direct anti-inflammatory effects, (2) improved epithelial barrier function, and (3) modulation of the gut microbiota. Recent studies have demonstrated that modulation of the gut microbiota plays a major role in EEN-induced remission. Variations of microbial components, which directly influence the diversity and metabolic functions of the gut microbiota, are closely associated with the immunological conditions of the gut and the susceptibility to diseases. The reduction of proinflammatory microbial components and harmful microbial metabolites after EEN treatment greatly decreases the inflammatory injuries of the gut.

The use of oral corticosteroids in inflammatory bowel diseases in Italy: An IG-IBD survey

AIM

To evaluate how Italian gastroenterologists use corticosteroids in clinical practice for the treatment of Crohn's disease (CD) and ulcerative colitis (UC).

MATERIAL AND METHODS

All members of the Italian Group for Inflammatory Bowel Disease (IG-IBD) were invited to fill in a web-based questionnaire.

RESULTS

131/448 (29.2%) members completed the survey. In mild-to-moderate UC and CD relapses, low-bioavailability steroids (LBS) are first-line therapy for 37% and 42% of clinicians, respectively. In case of failure, immediate step-up to biologics or immunosuppressants is considered by 23% and 29%. Regarding conventional corticosteroids (CCS), a fixed starting dose is prescribed by 50%, and a weight-based dose by 22%. Tapering is started after 7-10days by 41% and after 14days by 32%. The preferred tapering schedule is 5mg/week. In case of CCS failure, 47% switch to parenteral steroids before considering shifting to different drug classes. In case of symptoms recurrence during tapering, 14% re-increase the dose and try tapering again. Before prescribing steroids, 72% do not prescribe any specific evaluation whereas during treatment some evaluation is performed by 85%. Vitamin D and calcium supplements are routinely prescribed along with steroids by 38%.

CONCLUSIONS

Several discrepancies and some deviation from the available guidelines were recorded among Italian gastroenterologists regarding corticosteroids use in IBD patients.

Gut microbiota and IBD: causation or correlation?

A general consensus exists that IBD is associated with compositional and metabolic changes in the intestinal microbiota (dysbiosis). However, a direct causal relationship between dysbiosis and IBD has not been definitively established in humans. Findings from animal models have revealed diverse and context-specific roles of the gut microbiota in health and disease, ranging from protective to pro-inflammatory actions. Moreover, evidence from these experimental models suggest that although gut bacteria often drive immune activation, chronic inflammation in turn shapes the gut microbiota and contributes to dysbiosis. The purpose of this Review is to summarize current associations between IBD and dysbiosis, describe the role of the gut microbiota in the context of specific animal models of colitis, and discuss the potential role of microbiota-focused interventions in the treatment of human IBD. Ultimately, more studies will be needed to define host-microbial relationships relevant to human disease and amenable to therapeutic interventions.

Systematic review with meta-analysis: enteral nutrition therapy for the induction of remission in paediatric Crohn's disease

BACKGROUND

Despite potential adverse-events in a paediatric population, corticosteroids are used to induce remission in paediatric Crohn's disease. Exclusive enteral nutrition also induces remission, but is infrequently used in the USA because corticosteroids are considered the superior therapy. New data have become available since the publication of the most recent meta-analysis in 2007.

AIM

To see if current literature supports the use of EEN versus CS in paediatric populations.

METHODS

All studies with comparator arms of exclusive enteral nutrition and an exclusive corticosteroids, with remission clearly defined were identified by searching eight online databases.

RESULTS

Of 2795 identified sources, nine studies met our inclusion criteria. Eight of these (n = 451), had data that could be abstracted into our meta-analysis. Exclusive enteral nutrition was as effective as corticosteroids in inducing remission (OR = 1.26 [95% CI 0.77, 2.05]) in paediatric Crohn's disease. There was no difference between Exclusive enteral nutrition and corticosteroids efficacy when comparing newly diagnosed Crohn's (OR = 1.61 [95% CI .87, 2.98]) or relapsed (OR = 0.76 [95% CI .29-1.98]). Intestinal healing was significantly more likely among patients receiving Exclusive enteral nutrition compared to corticosteroids (OR = 4.5 [95% CI 1.64, 12.32]). There was no difference in the frequency of biomarker normalisation including CRP (OR = 0.85 [95% CI .44, 1.67]) and faecal calprotectin (OR 2.79 [95% CI .79-10.90]).

CONCLUSIONS

There is no difference in efficacy between exclusive enteral nutrition and corticosteroids in induction of remission in Crohn's disease in a paediatric population. Exploratory analyses suggest that a greater proportion of patients treated with exclusive enteral nutrition achieved mucosal healing.

The Role of Diet in Inflammatory Bowel Disease

PURPOSE OF REVIEW

Diet may play both a causal and therapeutic role for inflammatory bowel disease (IBD). Physicians caring for patients with IBD are often asked to make dietary recommendations. However, there are no well-established guidelines on the use of diet as a treatment of IBD. In this review, we describe the evidence supporting diet as a potential cause for IBD, patient-perceived symptoms based on diet, current research on various diets as a treatment for IBD, and areas of future research.

RECENT FINDINGS

New studies in murine models suggest that dietary emulsifiers may trigger the gut inflammatory cascade. New studies of restriction diets in patients have shown a relationship between dietary intake, symptoms, and bowel inflammation. Until several ongoing clinical trials are completed, a reasonable approach to dietary recommendations for patients with IBD is to propose a well-balanced, healthy (low-fat, low-sugar) diet prepared from fresh ingredients, such as the Mediterranean diet, with exclusions of self-identified foods that worsen or trigger IBD-related symptoms.

Exclusive Enteral Nutrition Therapy in Paediatric Crohn's Disease Results in Long-term Avoidance of Corticosteroids: Results of a Propensity-score Matched Cohort Analysis

BACKGROUND AND AIMS

Exclusive enteral nutrition [EEN] is recommended as a first-line induction therapy for paediatric Crohn's disease [CD] although corticosteroids [CS] are still used commonly. Our aim was to compare short- and long-term disease outcomes of paediatric CD patients initially managed with either EEN or CS.

METHODS

Medical records of newly diagnosed paediatric CD patients treated with EEN or CS as induction therapy were retrospectively reviewed. To minimise selection bias inherent in observational cohort studies, propensity analysis was carried out. Data on anthropometrics, medical history, and presenting phenotype were collected at time of diagnosis [baseline]; outcomes of interest, including medication use, hospitalisation, surgical procedures, and disease progression were assessed up to 6 years following diagnosis.

RESULTS

Of 127 patients reviewed, a total of 111 propensity-score matched CD patients receiving EEN [n = 76] or CS [n = 35] were analysed. By 4-12 weeks of induction therapy, 86.6% of EEN-treated patients achieved remission (Paediatric Crohn's Disease Activity Index [PCDAI] ≤ 7.5) compared with 58.1% of patients in the CS-treated group [p < 0.01]. Choice of EEN over CS for induction was associated with avoidance of corticosteroids over a 6-year follow-up period. Analysis of long-term linear growth, hospitalisation, need for biologic therapy, or surgical intervention did not reveal any significant differences.

CONCLUSIONS

These findings suggest that EEN induction therapy is more effective in achieving early remission and is associated with long-term steroid avoidance without increased use of biologics or need for surgery.

Efficacy of exclusive enteral nutrition in complicated Crohn's disease

AIM

To investigate the efficacy of exclusive enteral nutrition (EEN) in induction of remission in adult active Crohn's disease (CD) complicated with intestinal fistula/abdominal abscess or inflammatory intestinal stricture.

METHOD

Patients diagnosed with active CD with complications were recruited between July 2013 and July 2015. Patients were offered EEN for 12 weeks. Patients with abscess received antibiotic treatment with or without percutaneous drainage. Clinical variables were recorded (ClinicalTrials.gov Identifier: NCT02887287).

RESULTS

Forty-one patients with CD and with intestinal fistula/abdominal abscess or inflammatory intestinal stricture aged 18-60 years, were included. Ten patients were accompanied with stenosis and 33 with intestinal fistula/abscess. After 12 weeks of EEN, the Crohn's disease activity index significantly decreased (223.43 ± 65.5 vs. 106.77 ± 42.73, p ≤ .001), and 80.5% of patients achieved full clinical remission totally. Fistula closure after EEN was observed in 75% of patients with entero-cutaneous fistula. In patients with stenosis, 20% had no response to EEN and were transferred for surgery. Partial remission and full remission were observed in 20% and 60% of patients after 12 weeks of EEN, respectively. Intra-abdominal abscess resolved in 76% of patients. Seventeen patients who had mucosal ulcers underwent colonoscopy before and after EEN, 47% achieved mucosal healing after the treatment. The inflammatory index of patients significantly decreased (p ≤ .01), nutritional parameters increased (p ≤ .01) and the European Nutritional Risk Screening (2002) decreased (p ≤ .01).

CONCLUSION

EEN is effective in inducing early clinical remission, mucosal healing, promoting fistula closure and reducing the size of abscess in adult CD patients with complications.

Lack of Mucosal Healing From Modified Specific Carbohydrate Diet in Pediatric Patients With Crohn Disease

Exclusive enteral nutrition is effective in pediatric Crohn disease but challenging as maintenance therapy. There is interest in food-based therapies such as the specific carbohydrate diet (SCD) but paucity of data on efficacy and effect on mucosal healing, an evolving target of IBD therapy. We conducted a retrospective review of the mucosal healing effect of the SCD in pediatric Crohn disease (CD). The endoscopic findings for children younger than 18 years with CD treated exclusively with the SCD or modified SCD (mSCD; SCD + addition of "illegal foods") were reviewed before and after the diet. Ileocolonoscopic examinations were scored according to the Simple Endoscopic Score for CD and findings on upper endoscopy were described. Seven subjects were identified, all on mSCD. The average age at starting the SCD was 11 ± 3.4 years and median duration of SCD/mSCD therapy was 26 months. All subjects reported no active symptoms before repeat endoscopic evaluation on mSCD, the majority had consistently normal C-reactive protein, albumin and hematocrit assessments, and mildly elevated fecal calprotectin (>50 μg/g, median 201, range 65-312) at any point within 3 months before the repeat endoscopy. One patient showed complete ileocolonic healing but persistent upper gastrointestinal tract ulceration. Complete macroscopic mucosal healing of both the ileocolon and upper gastrointestinal tract was not seen in any patient.

Effects of the Exclusive Enteral Nutrition on the Microbiota Profile of Patients with Crohn's Disease: A Systematic Review

The mechanisms behind the efficacy of exclusive enteral nutrition (EEN) in Crohn's disease (CD) remain poorly understood, despite the high rate of treatment response. Evidence accumulated in the last 20 years suggests that a positive shift of the disrupted microbiota is one of the treatment effects. The purpose of this study was to critically review and summarize data reporting the microbiological effects of EEN in patients with CD. Fourteen studies were considered in the review, overall involving 216 CD patients on EEN. The studies were heterogeneous in methods of microbiota analysis and exclusion criteria. The most frequently reported effect of EEN was a reduction in microbiota diversity, reversible when patients returned to a normal diet. The effect of EEN on specific bacteria was very variable in the different studies, partially due to methodological limitations of the mentioned studies. The EEN seem to induce some metabolomic changes, which are different in long-term responder patients compared to patients that relapse earlier. Bacterial changes can be relevant to explaining the efficacy of EEN; however, microbiological data obtained from rigorously performed studies and derived from last generation techniques are largely inconsistent.

Nutritional Therapy in Very Early-Onset Inflammatory Bowel Disease: A Case Report

Inflammatory bowel disease (IBD) is a chronic inflammatory disease of the gastrointestinal tract caused by a dysregulated immune response to the fecal microbiota. Very early-onset inflammatory bowel disease (VEO-IBD) refers to a subgroup of pediatric patients with IBD diagnosed before 6 years of age. This subgroup is often characterized by increased severity, aggressive progression, strong family history of IBD, and often poor response to conventional treatments. Nutritional therapies have been utilized to treat IBD, but their role in VEO-IBD is unclear. Disease behavior in VEO-IBD is often different from disease in adolescents and adults, as it is often restricted to the colon and refractory to standard medical therapies. Up to 25% of VEO-IBD patients have an identified underlying immunodeficiency, which may impact response to therapy. While specific mutations in interleukin 10 (IL-10), the IL-10 receptor (IL-10R), and mutations in NCF2, XIAP, LRBA, and TTC7 have been identified in VEO-IBD, polymorphisms in these genes are also associated with increased risk of developing IBD in adolescence or adulthood. We describe two cases in which infants presenting with VEO-IBD achieved clinical remission using exclusive enteral nutrition, a formula-based diet which has been shown to induce remission in older children with active Crohn's disease.

The microbiota in inflammatory bowel disease: current and therapeutic insights

Inflammatory bowel disease is a heterogeneous group of chronic disorders that result from the interaction of the intestinal immune system with the gut microbiome. Until recently, most investigative efforts and therapeutic breakthroughs were centered on understanding and manipulating the altered mucosal immune response that characterizes these diseases. However, more recent studies have highlighted the important role of environmental factors, and in particular the microbiota, in disease onset and disease exacerbation. Advances in genomic sequencing technology and bioinformatics have facilitated an explosion of investigative inquiries into the composition and function of the intestinal microbiome in health and disease and have advanced our understanding of the interplay between the gut microbiota and the host immune system. The gut microbiome is dynamic and changes with age and in response to diet, antibiotics and other environmental factors, and these alterations in the microbiome contribute to disease onset and exacerbation. Strategies to manipulate the microbiome through diet, probiotics, antibiotics or fecal microbiota transplantation may potentially be used therapeutically to influence modulate disease activity. This review will characterize the factors involved in the development of the intestinal microbiome and will describe the typical alterations in the microbiota that are characteristic of inflammatory bowel disease. Additionally, this manuscript will summarize the early but promising literature on the role of the gut microbiota in the pathogenesis of inflammatory bowel disease with implications for utilizing this data for diagnostic or therapeutic application in the clinical management of patients with these diseases.

Diagnosis and management of inflammatory bowel disease in children

Inflammatory bowel diseases (IBD), including Crohn's disease and ulcerative colitis, are lifelong conditions that often begin in childhood. The implications of IBD are of particular importance in children because of the potential negative effects on growth, development, psychosocial function, and overall wellbeing. The key management strategy is to achieve sustained control of intestinal inflammation and monitor for potential complications of the disease and side effects of therapies. Overall, the evidence on the management of IBD in children is less extensive than in adults, but good quality multicenter studies and various guidelines and society consensus statements are available. This review summarizes the evidence on the pathophysiology, diagnosis, and approaches to management of children and adolescents with IBD.

The Impact of Exclusive Enteral Nutrition (EEN) on the Gut Microbiome in Crohn's Disease: A Review

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.

Exclusive enteral nutrition provides an effective bridge to safer interval elective surgery for adults with Crohn's disease

BACKGROUND

Few studies have reported the systematic use of exclusive enteral nutrition in the perioperative setting.

AIM

To test the hypothesis that exclusive enteral nutrition provides a safe and effective bridge to surgery and reduces post-operative complications, in adult patients with Crohn's disease requiring urgent surgery for stricturing or penetrating complications.

METHODS

Patients treated with exclusive enteral nutrition prior to surgery were each matched with two control patients for disease behaviour, type of surgery, age at diagnosis and disease duration. Data on disease phenotype, nutritional status, operative course and post-operative complications were obtained.

RESULTS

Twenty-five per cent [13/51] patients treated with exclusive enteral nutrition avoided surgery. Exclusive enteral nutrition had no effect on pre-operative weight, but it significantly reduced serum CRP [median at baseline 36 (interquartile range, IQR: 13-91] vs. pre-operation 8 (4-31) mg/L, P = 0.02]. The median (IQR) length of surgery was shorter in patients pre-optimised with exclusive enteral nutrition than controls [3.0 (2.5-3.5) vs. 3.5 (3.0-4.0) hours respectively, P < 0.001]. Multivariable logistic regression analysis confirmed that going straight-to-surgery compared exclusive enteral nutrition pre-optimisation was associated with a ninefold increase in the incidence of post-operative abscess and/or anastomotic leak [OR 9.1; 95% CI (1.2-71.2), P = 0.04].

CONCLUSIONS

Exclusive enteral nutrition frequently down-stages the need for surgery in patients presenting with stricturing or penetrating complications of Crohn's disease; it is associated with a reduction in systemic inflammation, operative times and the incidence of post-operative abscess or anastomotic leak. Further trials are needed to elucidate how exclusive enteral nutrition may improve operative outcomes.

Diet as a Trigger or Therapy for Inflammatory Bowel Diseases

The most common question asked by patients with inflammatory bowel disease (IBD) is, "Doctor, what should I eat?" Findings from epidemiology studies have indicated that diets high in animal fat and low in fruits and vegetables are the most common pattern associated with an increased risk of IBD. Low levels of vitamin D also appear to be a risk factor for IBD. In murine models, diets high in fat, especially saturated animal fats, also increase inflammation, whereas supplementation with omega 3 long-chain fatty acids protect against intestinal inflammation. Unfortunately, omega 3 supplements have not been shown to decrease the risk of relapse in patients with Crohn's disease. Dietary intervention studies have shown that enteral therapy, with defined formula diets, helps children with Crohn's disease and reduces inflammation and dysbiosis. Although fiber supplements have not been shown definitively to benefit patients with IBD, soluble fiber is the best way to generate short-chain fatty acids such as butyrate, which has anti-inflammatory effects. Addition of vitamin D and curcumin has been shown to increase the efficacy of IBD therapy. There is compelling evidence from animal models that emulsifiers in processed foods increase risk for IBD. We discuss current knowledge about popular diets, including the specific carbohydrate diet and diet low in fermentable oligo-, di-, and monosaccharides and polyols. We present findings from clinical and basic science studies to help gastroenterologists navigate diet as it relates to the management of IBD.

The Importance and Challenges of Dietary Intervention Trials for Inflammatory Bowel Disease

Inflammatory bowel disease is believed to be caused by a combination of genetic and environmental stimuli such as our diet. Diets high in meat and fats and low in fruits and vegetables have been associated with new-onset inflammatory bowel disease. This has triggered interest in using dietary modification as a treatment. The 3 principle models of dietary intervention are supplementation with selected dietary components, exclusion of selected dietary components, or use of dietary formulas in place of a normal diet. Despite the high level of interest in dietary interventions as a treatment for inflammatory bowel disease, few well-designed clinical trials have been conducted to firmly establish the optimal diet to induce or maintain remission. This may be in part related to the challenges of conducting dietary intervention trials. This review examines these challenges and potential approaches to be used in dietary intervention trials.

The Impact of Dietary Interventions on the Symptoms of Inflammatory Bowel Disease: A Systematic Review

Diet may be a successful part of the treatment plan for improving outcome in patients with inflammatory bowel disease (IBD). This study aimed to systematically review all published clinical trials evaluating the effects of a regular diet on symptoms of IBD. Three medical databases were searched for clinical trials evaluating an intervention that involved dietary manipulation using a regular diet on adults with IBD whose symptoms were objectively measured before and after the intervention. The most common types of regular diet interventions that we observed in the literature fell into the following three categories: low residue/low fiber diets, exclusion diets, or other specific diets. Of all included studies, the few that were of higher quality and that observed a statistically significant improvement in symptoms in the diet group compared to the control group fell under the exclusion diet group or the other specific diet group. We were able to identify several high quality clinical trials evaluating dietary manipulations on symptoms of IBD. Exclusion diets and the low FODMAP diet are two areas identified in this review that show promise for having therapeutic benefits for patients with IBD.

Towards an integrated understanding of the therapeutic utility of exclusive enteral nutrition in the treatment of Crohn's disease

Crohn's disease (CD) is a chronic disease characterized by episodic and disabling inflammation of the gastrointestinal tract in genetically susceptible individuals. The incidence and prevalence of CD is rising rapidly across the world emphasising that disease risk is also influenced by environmental and lifestyle factors, as well as the microbial community resident in the gut. Childhood-onset CD is associated with an aggressive disease course that can adversely impact patient growth and development. There is no cure for CD however new onset and recurrent cases of paediatric CD are often responsive to exclusive enteral nutrition (EEN) treatment. EEN treatment involves the exclusive consumption of an elemental or polymeric formula for several weeks and it is well established as a primary intervention strategy. EEN treatments typically achieve remission rates of over 80% and importantly they are associated with a high rate of mucosal healing, far superior to steroids, which is prognostic of improved long-term health outcomes. Furthermore, they are safe, have few side effects, and improve nutritional status and linear growth. Surprisingly, despite the utility of EEN our understanding of the host-microbe-diet interactions that underpin clinical remission and mucosal healing are limited. Here, we review the current state of knowledge and propose that the induction of autophagy, in addition to modulation of the microbiota and coordinated effects on inflammation and epithelial cell biology, may be critical for the therapeutic effects associated with EEN. A better understanding of EEN treatment will provide new opportunities to restore gut homeostasis and prolong periods of remission, as well as provide new insights into the factors that trigger and perhaps prevent CD.

ESPEN guideline: Clinical nutrition in inflammatory bowel disease

INTRODUCTION

The ESPEN guideline presents a multidisciplinary focus on clinical nutrition in inflammatory bowel disease (IBD).

METHODOLOGY

The guideline is based on extensive systematic review of the literature, but relies on expert opinion when objective data were lacking or inconclusive. The conclusions and 64 recommendations have been subject to full peer review and a Delphi process in which uniformly positive responses (agree or strongly agree) were required.

RESULTS

IBD is increasingly common and potential dietary factors in its aetiology are briefly reviewed. Malnutrition is highly prevalent in IBD - especially in Crohn's disease. Increased energy and protein requirements are observed in some patients. The management of malnutrition in IBD is considered within the general context of support for malnourished patients. Treatment of iron deficiency (parenterally if necessary) is strongly recommended. Routine provision of a special diet in IBD is not however supported. Parenteral nutrition is indicated only when enteral nutrition has failed or is impossible. The recommended perioperative management of patients with IBD undergoing surgery accords with general ESPEN guidance for patients having abdominal surgery. Probiotics may be helpful in UC but not Crohn's disease. Primary therapy using nutrition to treat IBD is not supported in ulcerative colitis, but is moderately well supported in Crohn's disease, especially in children where the adverse consequences of steroid therapy are proportionally greater. However, exclusion diets are generally not recommended and there is little evidence to support any particular formula feed when nutritional regimens are constructed.

CONCLUSIONS

Available objective data to guide nutritional support and primary nutritional therapy in IBD are presented as 64 recommendations, of which 9 are very strong recommendations (grade A), 22 are strong recommendations (grade B) and 12 are based only on sparse evidence (grade 0); 21 recommendations are good practice points (GPP).

Dietary and enteral interventions for Crohn's disease

It is now widely acknowledged that the intestinal bacterial flora together with genetic predisposing factors significantly contribute to the immunopathogenesis of inflammatory bowel disease (IBD) as reflected by mucosal immune dysregulation. Recently, there has been an increased interest in nutraceutical therapies, including probiotics, prebiotics and synbiotics. Other dietary interventions with low carbohydrate diet, omega-3 polyunsaturated fatty acids and glutamine have been attempted to downregulate the gut inflammatory response and thereby alleviate gastrointestinal symptoms. Enteral nutrition has been widely used as induction and maintenance therapies in the management of Crohn's disease (CD). In this review, a critical assessment of the results of clinical trial outcomes and meta-analyses was conducted to evaluate the efficacy of dietary and enteral interventions for CD.

Early Changes in Microbial Community Structure Are Associated with Sustained Remission After Nutritional Treatment of Pediatric Crohn's Disease

BACKGROUND

Clinical remission achieved by exclusive enteral nutrition (EEN) is associated with marked microbiome changes. In this prospective study of exclusive enteral nutrition, we employ a hierarchical model of microbial community structure to distinguish between pediatric Crohn's disease patients who achieved sustained remission (SR) and those who relapsed early (non-SR), after restarting a normal diet.

METHODS

Fecal samples were obtained from 10 patients (age 10-16) and from 5 healthy controls (age 9-14). The microbiota was assessed via 16S rRNA sequencing. In addition to standard measures of microbial biodiversity, we employed Bayesian methods to characterize the hierarchical community structure. Community structure between patients who sustained remission (wPCDAI <12.5) up to their 24-week follow-up (SR) was compared with patients that had not sustained remission (non-SR).

RESULTS

Microbial diversity was lower in Crohn's disease patients relative to controls and lowest in patients who did not achieve SR. SR patients differed from non-SR patients in terms of the structure and prevalence of their microbial communities. The SR prevalent community contained a number of strains of Akkermansia muciniphila and Bacteroides and was limited in Proteobacteria, whereas the non-SR prevalent community had a large Proteobacteria component. Their communities were so different that a model trained to discriminate SR and non-SR had 80% classification accuracy, already at baseline sampling.

CONCLUSIONS

Microbial community structure differs between healthy controls, patients who have an enduring response to exclusive enteral nutrition, and those who relapse early on introduction of normal diet. Our novel Bayesian approach to these differences is able to predict sustained remission after exclusive enteral nutrition.

The Gut Microbiome of Pediatric Crohn's Disease Patients Differs from Healthy Controls in Genes That Can Influence the Balance Between a Healthy and Dysregulated Immune Response

BACKGROUND

Exclusive enteral nutrition (EEN) is a first-line therapy in pediatric Crohn's disease (CD) thought to induce remission through changes in the gut microbiome. With microbiome assessment largely focused on microbial taxonomy and diversity, it remains unclear to what extent EEN induces functional changes that thereby contribute to its therapeutic effect.

METHODS

Fecal samples were collected from 15 pediatric CD patients prior to and after EEN treatment, as well as from 5 healthy controls. Metagenomic data were obtained via next-generation sequencing, and nonhuman reads were mapped to KEGG pathways, where possible. Pathway abundance was compared between CD patients and controls, and between CD patients that sustained remission (SR) and those that did not sustain remission (NSR).

RESULTS

Of 132 KEGG pathways identified, 8 pathways differed significantly between baseline CD patients and controls. Examination of these eight pathways showed SR patients had greater similarity to controls than NSR patients in all cases. Pathways fell into one of three groups: 1) no prior connection to IBD, 2) previously reported connection to IBD, and 3) known roles in innate immunity and immunoregulation.

CONCLUSIONS

The microbiota of CD patients and controls represent alternative ecological states that have broad differences in functional capabilities, including xenobiotic and environmental pollutant degradation, succinate metavolism, and bacterial HtpG, all of which can affect barrier integrity and immune regulation. Moreover, our finding that SR patients were more similar to healthy controls suggests that community microbial function, as inferred from fecal microbiomes, could serve as a valuable diagnostic tool.

Diet, gut microbes, and the pathogenesis of inflammatory bowel diseases

The rising incidence of inflammatory bowel diseases in recent decades has notably paralleled changing lifestyle habits in Western nations, which are now making their way into more traditional societies. Diet plays a key role in IBD pathogenesis, and there is a growing appreciation that the interaction between diet and microbes in a susceptible person contributes significantly to the onset of disease. In this review, we examine what is known about dietary and microbial factors that promote IBD. We summarize recent findings regarding the effects of diet in IBD epidemiology from prospective population cohort studies, as well as new insights into IBD-associated dysbiosis. Microbial metabolism of dietary components can influence the epithelial barrier and the mucosal immune system, and understanding how these interactions generate or suppress inflammation will be a significant focus of IBD research. Our knowledge of dietary and microbial risk factors for IBD provides important considerations for developing therapeutic approaches through dietary modification or re-shaping the microbiota. We conclude by calling for increased sophistication in designing studies on the role of diet and microbes in IBD pathogenesis and disease resolution in order to accelerate progress in response to the growing challenge posed by these complex disorders.

Time to Relapse in Children with Crohn's Disease Treated with Azathioprine and Nutritional Therapy or Corticosteroids

BACKGROUND

The duration of remission has been shown to be longer in patients initially treated with exclusive enteral nutrition (EEN) compared to corticosteroids (CS). However, no published studies required concurrent immunomodulator [6-mercaptopurine or azathioprine (AZA)] use at the time of diagnosis.

AIMS

The aims of this retrospective study were to compare the duration of remission between patients initially treated with AZA in combination with CS or EEN and identify predictors of early relapse in these patients.

METHODS

Data from 65 newly diagnosed children with CD in clinical remission on either EEN or CS and commencing AZA at diagnosis were included. We compared duration of remission using physician global assessment and carried out Cox regression analysis to identify predictors of early relapse. Patients were followed up to the time of first relapse or for at least 12 months.

RESULTS

There were no differences in the duration of remission between patients initially treated with EEN or CS (p = 0.978). We identified younger age at diagnosis [hazard ratio (HR) 0.87, 95 CI 0.78-0.98, p = 0.016], lower height Z score at diagnosis (HR 0.61, 95 CI 0.44-0.85, p = 0.003), involvement of the upper gastrointestinal tract (HR 2.69, 95 CI 1.27-5.66, p = 0.009), and elevated platelet count at remission (HR 1.004, 95 CI 1.001-1.008, p = 0.021) as independent predictors of early relapse.

CONCLUSIONS

Neither induction regime demonstrated longer duration of remission of CD in patients treated with immunomodulators since the time of diagnosis.

The intestinal microbiome, barrier function, and immune system in inflammatory bowel disease: a tripartite pathophysiological circuit with implications for new therapeutic directions

We discuss the tripartite pathophysiological circuit of inflammatory bowel disease (IBD), involving the intestinal microbiota, barrier function, and immune system. Dysfunction in each of these physiological components (dysbiosis, leaky gut, and inflammation) contributes in a mutually interdependent manner to IBD onset and exacerbation. Genetic and environmental risk factors lead to disruption of gut homeostasis: genetic risks predominantly affect the immune system, environmental risks predominantly affect the microbiota, and both affect barrier function. Multiple genetic and environmental 'hits' are likely necessary to establish and exacerbate disease. Most conventional IBD therapies currently target only one component of the pathophysiological circuit, inflammation; however, many patients with IBD do not respond to immune-modulating therapies. Hope lies in new classes of therapies that target the microbiota and barrier function.

Nutrition in Pediatric Inflammatory Bowel Disease: From Etiology to Treatment. A Systematic Review

Nutrition is involved in several aspects of pediatric inflammatory bowel disease (IBD), ranging from disease etiology to induction and maintenance of disease. With regards to etiology, there are pediatric data, mainly from case-control studies, which suggest that some dietary habits (for example consumption of animal protein, fatty foods, high sugar intake) may predispose patients to IBD onset. As for disease treatment, exclusive enteral nutrition (EEN) is an extensively studied, well established, and valid approach to the remission of pediatric Crohn’s disease (CD). Apart from EEN, several new nutritional approaches are emerging and have proved to be successful (specific carbohydrate diet and CD exclusion diet) but the available evidence is not strong enough to recommend this kind of intervention in clinical practice and new large experimental controlled studies are needed, especially in the pediatric population. Moreover, efforts are being made to identify foods with anti-inflammatory properties such as curcumin and long-chain polyunsaturated fatty acids n-3, which can possibly be effective in maintenance of disease. The present systematic review aims at reviewing the scientific literature on all aspects of nutrition in pediatric IBD, including the most recent advances on nutritional therapy.