Double-blind randomized controlled trial of glutamine-enriched polymeric diet in the treatment of active Crohn's disease

Intestinal microecology-based treatment for inflammatory bowel disease: Progress and prospects

Inflammatory bowel disease (IBD) is a chronic, recurrent, and debilitating disorder, and includes Crohn’s disease and ulcerative colitis. The pathogenesis of IBD is closely associated with intestinal dysbiosis, but has not yet been fully clarified. Genetic and environmental factors can influence IBD patients’ gut microbiota and metabolism, disrupt intestinal barriers, and trigger abnormal immune responses. Studies have reported the alteration of gut microbiota and metabolites in IBD, providing the basis for potential therapeutic options. Intestinal microbiota-based treatments such as pre/probiotics, metabolite supplementation, and fecal microbiota transplantation have been extensively studied, but their clinical efficacy remains controversial. Repairing the intestinal barrier and promoting mucosal healing have also been proposed. We here review the current clinical trials on intestinal microecology and discuss the prospect of research and practice in this field.

Novel technologies to characterize and engineer the microbiome in inflammatory bowel disease

We present an overview of recent experimental and computational advances in technology used to characterize the microbiome, with a focus on how these developments improve our understanding of inflammatory bowel disease (IBD). Specifically, we present studies that make use of flow cytometry and metabolomics assays to provide a functional characterization of microbial communities. We also describe computational methods for strain-level resolution, temporal series, mycobiome and virome data, co-occurrence networks, and compositional data analysis. In addition, we review novel techniques to therapeutically manipulate the microbiome in IBD. We discuss the benefits and drawbacks of these technologies to increase awareness of specific biases, and to facilitate a more rigorous interpretation of results and their potential clinical application. Finally, we present future lines of research to better characterize the relation between microbial communities and IBD pathogenesis and progression.

When is enteral nutrition indicated?

Enteral nutrition (EN) is a vital component of nutrition around the world. EN allows for delivery of nutrients to those who cannot maintain adequate nutrition by oral intake alone. Common questions regarding EN are when to initiate and in what scenarios it is safe. The answers to these questions are often complex and require an evidence-based approach. The Board of Directors of the American Society for Parenteral and Enteral Nutrition (ASPEN) established an Enteral Nutrition Committtee to address the important questions surrounding the indications for EN. Consensus recommendations were established based on eight extremely clinically relevant questions regarding EN indications as deemed by the Enteral Nutrition Committee. These consensus recommendations may act as a guide for clinicians and stakeholders on difficult questions pertaining to indications for EN. This paper was approved by the ASPEN Board of Directors.

Effect of L-Glutamine on Chylomicron Formation and Fat-Induced Activation of Intestinal Mucosal Mast Cells in Sprague-Dawley Rats

Glutamine (Gln) is required for intestinal mucosal homeostasis, and it can promote triglyceride absorption. The intestinal mucosal mast cells (MMCs) are activated during fat absorption. This study investigated the potential role of Gln on fat absorption-induced activation of MMCs in rats. Lymph fistula rats (n = 24) were studied after an overnight recovery with the infusion of saline only, saline plus 85 mM L-glutamine (L-Gln) or 85 mM D-glutamine (D-Gln), respectively. On the test day, rats (n = 8/group) were given an intraduodenal bolus of 20% Intralipid contained either saline only (vehicle group), 85 mM L-Gln (L-Gln group), or 85 mM D-Gln (D-Gln group). Lymph was collected hourly for up to 6 h for analyses. The results showed that intestinal lymph from rats given L-Gln had increased levels of apolipoprotein B (ApoB) and A-I (ApoA-I), concomitant with an increased spectrum of smaller chylomicron particles. Unexpectedly, L-Gln also increased levels of rat mucosal mast cell protease II (RMCPII), as well as histamine and prostaglandin D2 (PGD2) in response to dietary lipid. However, these effects were not observed in rats treated with 85 mM of the stereoisomer D-Gln. Our results showed that L-glutamine could specifically activate MMCs to degranulate and release MMC mediators to the lymph during fat absorption. This observation is potentially important clinically since L-glutamine is often used to promote gut health and repair leaky gut.

EEN Yesterday and Today … CDED Today and Tomorrow

The treatment of Pediatric Crohn’s Disease (CD) requires attention both to achieve mucosal healing and to optimize growth, while also maintaining proper bone health. Exclusive Enteral Nutrition (EEN) is recommended as first-line treatment in luminal CD. The therapeutic mechanisms of EEN are being discovered by advances in the study of the gut microbiota. Although the total exclusion of a normal diet during the time of EEN continues to be of high importance, new modalities of dietary treatment suggest a successful future for the nutritional management of CD. In this sense, Crohn’s Disease Exclusion Diet (CDED) is a long-term strategy, it apparently acts on the mechanisms that influence the appearance of inflammation (reducing dietary exposure to products negatively affecting the microbiota), but does so using specific available whole foods to achieve this goal, increases the time of clinical remission and promotes healthy lifestyle habits. The development of CDED, which partly minimizes the problems of EEN, has enabled a turnaround in the treatment of pediatric CD. This review highlights the role of enteral nutrition in the treatment of Crohn’s disease with special emphasis on newer dietary modalities such as CDED.

[Crohn's Disease Exclusion Diet - an alternative to exlusive enteral nutritional therapy in children and adolescents with Crohn's disease? Statement of the GPGE working groups CEDATA and Nutrition/Nutrition Medicine]

Epidemiological an clinical observations as well as results from animal studies indicate that nutrition can play a role in the development of inflammatory bowel disease (IBD). Exclusive enteral nutrition therapy represents an example for modulating inflammatory responses solely through diet modification. Therefore, caretakers, patients, families, doctors and nutritionists seek for more dietary options to control IBD. These options include partial enteral nutrition therapy as for example the socalled Crohn's disease exclusion diet. The following statement summarizes existing data and provides recommendations for the current management of enteral nutrition therapy in pediatric Crohn's disease.

The Gastrointestinal Exertional Heat Stroke Paradigm: Pathophysiology, Assessment, Severity, Aetiology and Nutritional Countermeasures

Exertional heat stroke (EHS) is a life-threatening medical condition involving thermoregulatory failure and is the most severe condition along a continuum of heat-related illnesses. Current EHS policy guidance principally advocates a thermoregulatory management approach, despite growing recognition that gastrointestinal (GI) microbial translocation contributes to disease pathophysiology. Contemporary research has focused to understand the relevance of GI barrier integrity and strategies to maintain it during periods of exertional-heat stress. GI barrier integrity can be assessed non-invasively using a variety of in vivo techniques, including active inert mixed-weight molecular probe recovery tests and passive biomarkers indicative of GI structural integrity loss or microbial translocation. Strenuous exercise is strongly characterised to disrupt GI barrier integrity, and aspects of this response correlate with the corresponding magnitude of thermal strain. The aetiology of GI barrier integrity loss following exertional-heat stress is poorly understood, though may directly relate to localised hyperthermia, splanchnic hypoperfusion-mediated ischemic injury, and neuroendocrine-immune alterations. Nutritional countermeasures to maintain GI barrier integrity following exertional-heat stress provide a promising approach to mitigate EHS. The focus of this review is to evaluate: (1) the GI paradigm of exertional heat stroke; (2) techniques to assess GI barrier integrity; (3) typical GI barrier integrity responses to exertional-heat stress; (4) the aetiology of GI barrier integrity loss following exertional-heat stress; and (5) nutritional countermeasures to maintain GI barrier integrity in response to exertional-heat stress.

Inducing remission in paediatric Crohn's disease using nutritional therapies - A systematic review

BACKGROUND

Exclusive enteral nutrition (EEN) is known to be a safe and effective treatment option for managing active Crohn's disease (CD) in children, although no uniform protocol exists. The aim of this systematic review was to evaluate and compare the clinical effectiveness of aspects of EEN protocols to ascertain whether an optimum regimen can be identified.

METHODS

A systematic search of the Cochrane Library, PubMed, MEDLINE, EMBASE, CINAHL and AMED was conducted for studies published between 1998 and 2018 that examined paediatric patients being treated with an enteral nutrition protocol to induce remission. Studies that included patients receiving concurrent medication for active disease were excluded. Quality assessment was performed using separate tools for randomised controlled trials, cohort studies and for studies without a control group.

RESULTS

Sixteen studies met the inclusion criteria. Of these, six found insufficient evidence to support use of a specific formula. One study examined the route of EEN, finding no difference between oral or nasogastric tube administration with respect to inducing remission. Three examined the use of partial enteral nutrition to induce remission, although conflicting results were seen. No studies explored the effect of length of treatment or energy prescription on remission rates CONCLUSIONS: An optimum enteral nutrition protocol for inducing remission cannot be identified. Further focused research is required by well designed, adequately powered prospective clinical trials to examine aspects of enteral feeding protocols that remain uncertain, including the use of partial enteral nutrition as a potential alternative to EEN.

Characteristics of polymeric formula and route of delivery of exclusive enteral nutrition have no effect on disease outcome and weight gain in pediatric Crohn's disease

BACKGROUND & AIMS

This study aimed to evaluate the effect of the route of exclusive enteral nutrition (EEN) delivery (orally or via nasogastric (NG) tube) and type of polymeric formula (with taste vs tasteless and isocaloric vs hypercaloric) on the disease outcome and nutritional status in children with Crohn's disease (CD).

METHODS

This was a single center retrospective study which included all CD patients whose active disease at diagnosis was treated with EEN in the period from October 2007 to November 2017. All patients received polymeric formula orally or through a NG tube, which was based on the physicians and child's preference.

RESULTS

A total of 92 CD patients were included in the study (mean age 13.6 ± 3.0 years; 45.7% female). Overall, 42 (45.7%) patients received EEN via NG tube until the end of the EEN period. Remission was achieved in 71 (77.2%) children. There was no difference in the EEN failure status, remission duration, inflammatory markers, and weight gain at the end of the EEN period between oral intake and NG tube groups. None of the factors including age, disease location, type of formula (with taste vs tasteless and isocaloric vs hypercaloric) and mode of delivery (orally vs through NG tube for the whole duration of EEN) demonstrated an association with EEN failure.

CONCLUSION

This study failed to demonstrate an effect of the route of EEN delivery and the characteristics of the polymeric formula on the outcome of treatment in pediatric patients with CD.

The Role of Dietary Nutrients in Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is a chronic and relapsing inflammatory disease of the gastrointestinal tract. Although the precise etiology of IBD remains incompletely understood, accumulating evidence suggests that various environmental factors, including dietary nutrients, contribute to its pathogenesis. Dietary nutrients are known to have an impact on host physiology and diseases. The interactions between dietary nutrients and intestinal immunity are complex. Dietary nutrients directly regulate the immuno-modulatory function of gut-resident immune cells. Likewise, dietary nutrients shape the composition of the gut microbiota. Therefore, a well-balanced diet is crucial for good health. In contrast, the relationships among dietary nutrients, host immunity and/or the gut microbiota may be perturbed in the context of IBD. Genetic predispositions and gut dysbiosis may affect the utilization of dietary nutrients. Moreover, the metabolism of nutrients in host cells and the gut microbiota may be altered by intestinal inflammation, thereby increasing or decreasing the demand for certain nutrients necessary for the maintenance of immune and microbial homeostasis. Herein, we review the current knowledge of the role dietary nutrients play in the development and the treatment of IBD, focusing on the interplay among dietary nutrients, the gut microbiota and host immune cells. We also discuss alterations in the nutritional metabolism of the gut microbiota and host cells in IBD that can influence the outcome of nutritional intervention. A better understanding of the diet-host-microbiota interactions may lead to new therapeutic approaches for the treatment of IBD.

Enteral nutrition for maintenance of remission in Crohn's disease

BACKGROUND

Prevention of relapse is a major issue in the management of quiescent Crohn's disease (CD). Current therapies (e.g. methotrexate, biologics, 6-mercaptopurine and azathioprine) may be effective for maintaining remission in CD, but these drugs may cause significant adverse events. Interventions that are effective and safe for maintenance of remission in CD are desirable.

OBJECTIVES

The primary objectives were to evaluate the efficacy and safety of enteral nutrition for the maintenance of remission in CD and to assess the impact of formula composition on effectiveness.

SEARCH METHODS

We searched MEDLINE, Embase, CENTRAL, the Cochrane IBD Group Specialized Register and clinicaltrials.gov from inception to 27 July 2018. We also searched references of retrieved studies and reviews.

SELECTION CRITERIA

Randomised controlled trials (RCTs) including participants of any age with quiescent CD were considered for inclusion. Studies that compared enteral nutrition with no intervention, placebo or any other intervention were selected for review.

DATA COLLECTION AND ANALYSIS

Two authors independently screened studies for inclusion, extracted data and assessed methodological quality using the Cochrane risk of bias tool. The primary outcome was clinical or endoscopic relapse as defined by the primary studies. Secondary outcomes included anthropometric measures (i.e. height and weight), quality of life (QoL), adverse events, serious adverse events and withdrawal due to adverse events. We calculated the risk ratio and 95% confidence interval (CI) for dichotomous outcomes. For continuous outcomes, we calculated the mean difference and 95% CI. A random-effects model was used for the statistical analysis. We used the GRADE criteria to assess the overall certainty of the evidence supporting the primary outcome and selected secondary outcomes.

MAIN RESULTS

Four RCTs (262 adult participants) met the inclusion criteria. One study (N = 33) compared an elemental diet to a non-elemental (polymeric) diet. One study (N = 51) compared a half elemental diet to a regular free diet. Another study (N = 95) compared an elemental diet to 6-mercaptopurine (6-MP) or a no treatment control group. One study (N= 83) compared a polymeric diet to mesalamine. Two studies were rated as high risk of bias due to lack of blinding or incomplete outcome data. The other two studies were judged to have an unclear risk of bias. The studies were not pooled due to differences in control interventions and the way outcomes were assessed.The effect of an elemental diet compared to a polymeric diet on remission rates or withdrawal due to adverse events is uncertain. Fifty-eight per cent (11/19) of participants in the elemental diet group relapsed at 12 months compared to 57% (8/14) of participants in the polymeric diet group (RR 1.01, 95% CI 0.56 to 1.84; very low certainty evidence). Thirty-two per cent (6/19) of participants in the elemental diet group were intolerant to the enteral nutritional formula because of taste or smell and were withdrawn from the study in the first 2 weeks compared to zero participants (0/14) in the polymeric diet group (RR 9.75, 95% CI 0.59 to 159.93; low certainty evidence). Anthropometric measures, QoL, adverse events and serious adverse events were not reported as outcomes.The effect of an elemental diet (half of total daily calorie requirements) compared to a normal free diet on relapse rates is uncertain. Thirty-five per cent (9/26) of participants in the elemental diet group relapsed at 12 months compared to 64% (16/25) of participants in the free diet group (RR 0.54, 95% CI 0.30 to 0.99; very low certainty evidence). No adverse events were reported. This study reported no differences in weight change between the two diet groups. Height and QoL were not reported as outcomes.The effect of an elemental diet compared to 6-MP on relapse rates or adverse events is uncertain. Thirty-eight per cent (12/32) of participants in the elemental diet group relapsed at 12 months compared to 23% (7/30) of participants in the 6-MP group (RR 1.61; 95% CI 0.73 to 3.53; very low certainty evidence). Three per cent (1/32) of participants in the elemental diet group had an adverse event compared to 13% (4/30) of participants in the 6-MP group (RR 0.23, 95% CI 0.03 to 1.98; low certainty evidence). Adverse events in the elemental diet group included surgery due to worsening CD. Adverse events in the 6-MP group included liver injury (n = 2), hair loss (n = 1) and surgery due to an abscess (n = 1). No serious adverse events or withdrawals due to adverse events were reported. Weight, height and QoL were not reported as outcomesThe effect of a polymeric diet compared to mesalamine on relapse rates and weight is uncertain. Forty-two per cent (18/43) of participants in the polymeric diet group relapsed at 6 months compared to 55% (22/40) of participants in the mesalamine group (RR 0.76; 95% CI 0.49 to 1.19; low certainty evidence). The mean difference in weight gain over the study period was 1.9 kg higher in the polymeric diet group compared to mesalamine (95% CI -4.62 to 8.42; low certainty evidence). Two participants in the polymeric diet group experienced nausea and four had diarrhoea. It is unclear if any participants in the mesalamine group had an adverse event. Height, QoL, serious adverse events and withdrawal due to adverse events were not reported as outcomes.

AUTHORS' CONCLUSIONS

The results for the outcomes assessed in this review are uncertain and no firm conclusions regarding the efficacy and safety of enteral nutrition in quiescent CD can be drawn. More research is needed to determine the efficacy and safety of using enteral nutrition as maintenance therapy in CD. Currently, there are four ongoing studies (estimated enrolment of 280 participants). This review will be updated when the results of these studies are available.

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.

Nutritional Interventions in the Patient with Inflammatory Bowel Disease

Nutritional strategies have been explored as primary or adjunct therapies for inflammatory bowel disease (IBD). Exclusive enteral nutrition is effective for the induction of remission in Crohn disease and is recommended as a first-line therapy for children. Dietary strategies focus on adjusting the ratio of consumed nutrients that are proinflammatory or antiinflammatory. Treatments with dietary supplements focus on the antiinflammatory effects of the individual supplements (eg, curcumin, omega-3 fatty acids, vitamin D) or their positive effects on the intestinal microbiome (eg, prebiotics, probiotics). This article discusses the role of diets and dietary supplements in the treatment of IBD.

Specific protein supplementation using soya, casein or whey differentially affects regional gut growth and luminal growth factor bioactivity in rats; implications for the treatment of gut injury and stimulating repair

Modulation of regional growth within specific segments of the bowel may have clinical value for several gastrointestinal conditions. We therefore examined the effects of different dietary protein sources on regional gut growth and luminal growth factor bioactivity as potential therapies. Rats were fed for 14 days on isonitrogenous and isocaloric diets comprising elemental diet (ED) alone (which is known to cause gut atrophy), ED supplemented with casein or whey or a soya protein-rich feed. Effects on regional gut growth and intraluminal growth factor activity were then determined. Despite calorie intake being similar in all groups, soya rich feed caused 20% extra total body weight gain. Stomach weight was highest on soya and casein diets. Soya enhanced diet caused greatest increase in small intestinal weight and preserved luminal growth factor activity at levels sufficient to increase proliferation in vitro. Regional small intestinal proliferation was highest in proximal segment in ED fed animals whereas distal small intestine proliferation was greater in soya fed animals. Colonic weight and proliferation throughout the colon was higher in animals receiving soya or whey supplemented feeds. We conclude that specific protein supplementation with either soya, casein or whey may be beneficial to rest or increase growth in different regions of the bowel through mechanisms that include differentially affecting luminal growth factor bioactivity. These results have implications for targeting specific regions of the bowel for conditions such as Crohn's disease and chemotherapy.

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.

Metabolic Adaptations of CD4+ T Cells in Inflammatory Disease

A controlled and self-limiting inflammatory reaction generally results in removal of the injurious agent and repair of the damaged tissue. However, in chronic inflammation, immune responses become dysregulated and prolonged, leading to tissue destruction. The role of metabolic reprogramming in orchestrating appropriate immune responses has gained increasing attention in recent years. Proliferation and differentiation of the T cell subsets that are needed to address homeostatic imbalance is accompanied by a series of metabolic adaptations, as T cells traveling from nutrient-rich secondary lymphoid tissues to sites of inflammation experience a dramatic shift in microenvironment conditions. How T cells integrate information about the local environment, such as nutrient availability or oxygen levels, and transfer these signals to functional pathways remains to be fully understood. In this review, we discuss how distinct subsets of CD4⁺ T cells metabolically adapt to the conditions of inflammation and whether these insights may pave the way to new treatments for human inflammatory diseases.

The Roles of Glutamine in the Intestine and Its Implication in Intestinal Diseases

Glutamine, the most abundant free amino acid in the human body, is a major substrate utilized by intestinal cells. The roles of glutamine in intestinal physiology and management of multiple intestinal diseases have been reported. In gut physiology, glutamine promotes enterocyte proliferation, regulates tight junction proteins, suppresses pro-inflammatory signaling pathways, and protects cells against apoptosis and cellular stresses during normal and pathologic conditions. As glutamine stores are depleted during severe metabolic stress including trauma, sepsis, and inflammatory bowel diseases, glutamine supplementation has been examined in patients to improve their clinical outcomes. In this review, we discuss the physiological roles of glutamine for intestinal health and its underlying mechanisms. In addition, we discuss the current evidence for the efficacy of glutamine supplementation in intestinal diseases.

Dietary Protein and Amino Acid Supplementation in Inflammatory Bowel Disease Course: What Impact on the Colonic Mucosa?

Inflammatory bowel diseases (IBD), after disease onset, typically progress in two cyclically repeated phases, namely inflammatory flare and remission, with possible nutritional status impairment. Some evidence, either from epidemiological, clinical, and experimental studies indicate that the quantity and the quality of dietary protein consumption and amino acid supplementation may differently influence the IBD course according to the disease phases. For instance, although the dietary protein needs for mucosal healing after an inflammatory episode remain undetermined, there is evidence that amino acids derived from dietary proteins display beneficial effects on this process, serving as building blocks for macromolecule synthesis in the wounded mucosal area, energy substrates, and/or precursors of bioactive metabolites. However, an excessive amount of dietary proteins may result in an increased intestinal production of potentially deleterious bacterial metabolites. This could possibly affect epithelial repair as several of these bacterial metabolites are known to inhibit colonic epithelial cell respiration, cell proliferation, and/or to affect barrier function. In this review, we present the available evidence about the impact of the amount of dietary proteins and supplementary amino acids on IBD onset and progression, with a focus on the effects reported in the colon.

Exploring and Enhancing the Anti-Inflammatory Properties of Polymeric Formula

BACKGROUND

Exclusive enteral nutrition (EEN) therapy using a polymeric formula (PF) can substantially attenuate intestinal inflammation in Crohn's disease (CD) patients. However, the mechanism(s) by which EEN suppresses inflammation are not yet fully understood. The aims were to examine cellular mechanism(s) through which EEN may suppress inflammation and investigate potential pathways to enhance anti-inflammatory properties of EEN.

METHODS

Glutamine, arginine, vitamin D3, and α linolenic acid (ALA), present in PF, along with curcumin, were identified as immunoactive nutrient therapies. Tumor necrosis factor (TNF)-α-exposed HT-29 colonic epithelial cells were used to investigate the immunosuppressive activity of the nutrients by assessing their effect on cell viability, cell activity, chemokine response (interleukin-8 [IL-8]), nuclear factor (NF)-κB, P38 mitogen-activated protein kinase, IκB kinase (Iκκ), and nitric oxide (NO).

RESULTS

Cellular viability and activity were maintained with all nutrient treatments. Glutamine, arginine, and vitamin D3, but not ALA, significantly attenuated IL-8 production. Glutamine and arginine led to phosphorylation blockade of the signaling components in NF-κB and P38 pathways, reduction in kinase activity, and enhancement in NO production. Combining glutamine, arginine, and curcumin at optimal concentrations completely abolished the IL-8 response.

CONCLUSIONS

These data indicate that glutamine, arginine, and vitamin D3 can suppress inflammation at concentrations equivalent to those used in PF. The mechanisms of this action were mediated through influencing the NF-κB and P38 cascades. Glutamine and arginine-fortified PF with curcumin might be a promising option to enhance the effectiveness and expand the scope of EEN therapy in CD treatment.

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.

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.

Glutamine for induction of remission in Crohn's disease

BACKGROUND

Crohn's disease is a chronic relapsing condition of the alimentary tract with a high morbidity secondary to bowel inflammation. Glutamine plays a key role in maintaining the integrity of the intestinal mucosa and has been shown to reduce inflammation and disease activity in experimental models of Crohn's disease.

OBJECTIVES

To evaluate the efficacy and safety of glutamine supplementation for induction of remission in Crohn's disease.

SEARCH METHODS

We searched the following databases from inception to November 15, 2015: MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials, and the Cochrane IBD Group Specialised Register. Study references were also searched for additional trials. There were no language restrictions.

SELECTION CRITERIA

Randomised controlled trials (RCTs) that compared glutamine supplementation administered by any route to a placebo, active comparator or no intervention in people with active Crohn's disease were considered for inclusion.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data and assessed the methodological quality of the included studies. The Cochrane risk of bias tool was used to assess methodological quality. The primary outcome measure was clinical or endoscopic remission. Secondary outcomes included intestinal permeability, clinical response, quality of life, growth in children and adverse events. Risk ratios and 95% confidence intervals were calculated for dichotomous outcomes. The overall quality of the evidence supporting the primary outcome was evaluated using the GRADE criteria.

MAIN RESULTS

Two small RCTs (total 42 patients) met the inclusion criteria and were included in the review. One study (18 patients) compared four weeks of treatment with a glutamine-enriched polymeric diet (42% amino acid composition) to a standard polymeric diet (4% amino acid composition) with low glutamine content in paediatric patients (< 18 years of age) with active Crohn's disease. The other study (24 patients) compared glutamine-supplemented total parenteral nutrition to non-supplemented total parenteral nutrition in adult patients (> 18 years of age) with acute exacerbation of inflammatory bowel disease. The paediatric study was rated as low risk of bias. The study in adult patients was rated as unclear risk of bias for blinding and low risk of bias for all other items. It was not possible to pool data for meta-analysis because of significant differences in study populations, nature of interventions, and the way outcomes were assessed. Data from one study showed no statistically significant difference in clinical remission rates at four weeks. Forty-four per cent (4/9) of patients who received a glutamine-enriched polymeric diet achieved remission compared to 56% (5/9) of patients who received a standard low-glutamine polymeric diet (RR 0.80, 95% CI 0.31 to 2.04). A GRADE analysis indicated that the overall quality of evidence for this outcome was low due to serious imprecision (9 events). In both included studies, no statistically significant changes in intestinal permeability were found between patients who received glutamine supplementation and those who did not. Neither study reported on clinical response, quality of life or growth in children. Adverse event data were not well documented. There were no serious adverse events in the paediatric study. The study in adult patients reported three central catheter infections with positive blood cultures in the glutamine group compared to none in the control group (RR 7.00, 95% CI 0.40 to 122.44).

AUTHORS' CONCLUSIONS

Currently there is insufficient evidence to allow firm conclusions regarding the efficacy and safety of glutamine for induction of remission in Crohn's disease. Data from two small studies suggest that glutamine supplementation may not be beneficial in active Crohn's disease but these results need to be interpreted with caution as they are based on small numbers of patients. This review highlights the need for adequately powered randomised controlled trials to investigate the efficacy and safety of glutamine for induction of remission in Crohn's disease.

Oral protein calorie supplementation for children with chronic disease

BACKGROUND

Poor growth and nutritional status are common in children with chronic diseases. Oral protein calorie supplements are used to improve nutritional status in these children. These expensive products may be associated with some adverse effects, e.g. the development of inappropriate eating behaviour patterns. This is a new update of a Cochrane review last updated in 2009.

OBJECTIVES

To examine evidence that in children with chronic disease, oral protein calorie supplements alter daily nutrient intake, nutritional indices, survival and quality of life and are associated with adverse effects, e.g. diarrhoea, vomiting, reduced appetite, glucose intolerance, bloating and eating behaviour problems.

SEARCH METHODS

Trials of oral protein calorie supplements in children with chronic diseases were identified through comprehensive electronic database searches, handsearching relevant journals and abstract books of conference proceedings. Companies marketing these products were also contacted.Most recent search of the Group's Trials Register: 24 February 2015.

SELECTION CRITERIA

Randomised or quasi-randomised controlled trials comparing oral protein calorie supplements for at least one month to increase calorie intake with existing conventional therapy (including advice on improving nutritional intake from food or no specific intervention) in children with chronic disease.

DATA COLLECTION AND ANALYSIS

We independently assessed the outcomes: indices of nutrition and growth; anthropometric measures of body composition; calorie and nutrient intake (total from oral protein calorie supplements and food); eating behaviour; compliance; quality of life; specific adverse effects; disease severity scores; and mortality; we also assessed the risk of bias in the included trials.

MAIN RESULTS

Four studies (187 children) met the inclusion criteria. Three studies were carried out in children with cystic fibrosis and one study included children with paediatric malignant disease. Overall there was a low risk of bias for blinding and incomplete outcome data.Two studies had a high risk of bias for allocation concealment. Few statistical differences were found in the outcomes we assessed between treatment and control groups, except change in total energy intake at six and 12 months, mean difference 304.86 kcal per day (95% confidence interval 5.62 to 604.10) and mean difference 265.70 kcal per day (95% confidence interval 42.94 to 485.46), respectively. However, these were based on the analysis of just 58 children in only one study. Only two chronic diseases were included in these analyses, cystic fibrosis and paediatric malignant disease. No other studies were identified which assessed the effectiveness of oral protein calorie supplements in children with other chronic diseases.

AUTHORS' CONCLUSIONS

Oral protein calorie supplements are widely used to improve the nutritional status of children with a number of chronic diseases. We identified a small number of studies assessing these products in children with cystic fibrosis and paediatric malignant disease, but were unable to draw any conclusions based on the limited data extracted. We recommend a series of large, randomised controlled trials be undertaken investigating the use of these products in children with different chronic diseases. Until further data are available, we suggest these products are used with caution.

Consensus guidelines of ECCO/ESPGHAN on the medical management of pediatric Crohn's disease

Children and adolescents with Crohn's disease (CD) present often with a more complicated disease course compared to adult patients. In addition, the potential impact of CD on growth, pubertal and emotional development of patients underlines the need for a specific management strategy of pediatric-onset CD. To develop the first evidenced based and consensus driven guidelines for pediatric-onset CD an expert panel of 33 IBD specialists was formed after an open call within the European Crohn's and Colitis Organisation and the European Society of Pediatric Gastroenterolog, Hepatology and Nutrition. The aim was to base on a thorough review of existing evidence a state of the art guidance on the medical treatment and long term management of children and adolescents with CD, with individualized treatment algorithms based on a benefit-risk analysis according to different clinical scenarios. In children and adolescents who did not have finished their growth, exclusive enteral nutrition (EEN) is the induction therapy of first choice due to its excellent safety profile, preferable over corticosteroids, which are equipotential to induce remission. The majority of patients with pediatric-onset CD require immunomodulator based maintenance therapy. The experts discuss several factors potentially predictive for poor disease outcome (such as severe perianal fistulizing disease, severe stricturing/penetrating disease, severe growth retardation, panenteric disease, persistent severe disease despite adequate induction therapy), which may incite to an anti-TNF-based top down approach. These guidelines are intended to give practical (whenever possible evidence-based) answers to (pediatric) gastroenterologists who take care of children and adolescents with CD; they are not meant to be a rule or legal standard, since many different clinical scenario exist requiring treatment strategies not covered by or different from these guidelines.

Epithelial transport in inflammatory bowel diseases

The epithelium of the gastrointestinal tract is one of the most versatile tissues in the organism, responsible for providing a tight barrier between dietary and bacterial antigens and the mucosal and systemic immune system while maintaining efficient digestive and absorptive processes to ensure adequate nutrient and energy supply. Inflammatory bowel diseases (Crohn's disease and ulcerative colitis) are associated with a breakdown of both functions, which in some cases are clearly interrelated. In this updated literature review, we focus on the effects of intestinal inflammation and the associated immune mediators on selected aspects of the transepithelial transport of macronutrients and micronutrients. The mechanisms responsible for nutritional deficiencies are not always clear and could be related to decreased intake, malabsorption, and excess losses. We summarize the known causes of nutrient deficiencies and the mechanism of inflammatory bowel disease-associated diarrhea. We also overview the consequences of impaired epithelial transport, which infrequently transcend its primary purpose to affect the gut microbial ecology and epithelial integrity. Although some of those regulatory mechanisms are relatively well established, more work needs to be done to determine how inflammatory cytokines can alter the transport process of nutrients across the gastrointestinal and renal epithelia.

The role of total parenteral nutrition in inflammatory bowel disease: current aspects

Total parenteral nutrition (TPN) represents a therapeutic modality that could save the life of a patient with inflammatory bowel disease (IBD) facing severe nutritional problems, by restoring the patient's impaired nutritional status. TPN does not compete with enteral nutrition (EN), the latter being the first choice for all patients having anatomically intact and functionally normal digestive tract. TPN allows bowel rest while supplying adequate calorific intake and essential nutrients, and removes antigenic mucosal stimuli. The value of TPN in malnourished patients with intestinal failure due to CD is beyond doubt. However, it is difficult to suggest TPN as a sole treatment for active CD. An increased rate of remission could not be expected by applying TPN. The utility of TPN is restricted to certain cases involving efforts to close enterocutaneous or other complicated fistulas in patients with fistulizing CD, the treatment of short bowel syndrome following extensive resections for CD, or when EN is impractical for other reasons. There are no advantages of TPN therapy over EN therapy regarding fistula healing. TPN has no influence on the surgical intervention rate and little benefit by bypassing the intestinal passage could be expected. Also TPN shows no advantage if the disease is chronically active. However, an optimal supply of nutrients improves bowel motility, intestinal permeability and nutritional status, and reduces inflammatory reactions. TPN might be associated with an increased risk of adverse events, although TPN undertaken by experienced teams does not cause more complications than does EN.

Ingestion of low dose pyroglutamyl leucine improves dextran sulfate sodium-induced colitis and intestinal microbiota in mice

Inflammatory bowel diseases (IBD) are based on chronic inflammation in the gastrointestinal tract. We previously found anti-inflammatory peptide pyroGlu-Leu in the enzymatic hydrolysate of wheat gluten. The objective of present study is to elucidate improvement of colitis by oral administration of pyroGlu-Leu in an animal model. Acute colitis was induced by dextran sulfate sodium (DSS), and various concentrations of pyroGlu-Leu were administrated by oral gavage for 7 days. A dose of 0.1 mg/kg body weight/day showed the most significant improvement. The pyroGlu-Leu concentration was significantly increased 24 h after oral administration both in the small intestine and the colon compared with the baseline. It was 20-fold higher in the small intestine than the colon. Administration of pyroGlu-Leu normalized population of Bacteroidetes and Firmicutes in the colon. These results indicate that pyroGlu-Leu has a potential therapeutic effect against IBD at a practical dose.

Alanyl-glutamine administration suppresses Th17 and reduces inflammatory reaction in dextran sulfate sodium-induced acute colitis

T helper (Th) cells play a major role in the pathogenesis of inflammatory bowel disease (IBD). Glutamine (Gln) is known to have immunomodulatory effects in metabolic stressed conditions. This study investigated the effects of post-treatment of alanyl-glutamine (Ala-Gln) on Th cell-associated cytokine expressions and inflammatory reaction in dextran sulfate sodium (DSS)-induced colitis. C57BL/6 mice received distilled water containing 3% DSS for 5 days to induce colitis, whereas the normal control (NC) group received distilled water. After induction of colitis, one of the colitis groups (DG) was intraperitoneally injected with an Ala-Gln solution (0.5 g Gln/kg/d), and the saline DSS group (DS) received an identical volume of saline. After treatment for 3 days, mice were sacrificed, and the blood and tissue samples were collected for further analysis. DSS colitis resulted in higher percentages of blood interleukin (IL)-17-secreting Th cells and greater expression of Th cell-associated cytokine messenger RNA (mRNA) in the mesenteric lymph nodes (MLN). Also, luminal immunoglobin (Ig) G, keratinocyte-derived chemokine, and macrophage chemoattractant protein-1 levels were higher in the DS group than the NC group, whereas these parameters did not differ between the DG and NC groups. The DG group had lower blood IL-17A, 17F, MLN IL-17 mRNA and macrophage percentage in the peritoneal lavage fluid than those of the DS group. These results suggest that post-treatment with Ala-Gln suppressed Th17-associated cytokine expressions, reduced macrophage infiltration into the peritoneal cavity and decreased pro-inflammatory cytokine production in the colon, thus may have attenuated inflammatory response in DSS-induced colitis.

Nutrition and diet in inflammatory bowel disease

PURPOSE OF REVIEW

Diet is known to have a major role in the expression of inflammatory bowel disease (IBD). The role of dietary interventions and enteral nutrition in the management of IBD remains unelucidated. This study was to review the current evidence for dietary risk factors for the development of IBD and the efficacies of dietary and enteral interventions.

RECENT FINDINGS

High dietary intakes of total fats, polyunsaturated fatty acids, omega-6 fatty acids, and meat are associated with an increased risk of Crohn's disease and ulcerative colitis. Further prospective studies are required to confirm these observations. Among various dietary interventions, none has shown striking efficacy. Meta-analyses have shown enteral nutrition to be inferior to corticosteroids in adults with active Crohn's disease. However, in children, a meta-analysis has shown no significant difference in the remission rates between enteral nutrition and corticosteroid therapy. Although the evidence level is not striking, enteral nutrition may be useful for maintaining remission in patients with quiescent Crohn's disease.

SUMMARY

Dietary risk factors for IBD and the therapeutic benefit of dietary and enteral interventions need to be confirmed by further well designed studies in large cohorts of patients.

Nutritional management of adults with inflammatory bowel disease: practical lessons from the available evidence

Inflammatory bowel disease (IBD) is associated with impairment of nutritional status both anthropometrically and biochemically, which results from both qualitative and quantitative changes in dietary intake alongside disease activity. Dietary intervention to replace deficiency is essential and may also be used to treat active disease and to reduce symptoms. The evidence for dietary interventions in this area is reviewed and the following recommendations made: ■Assessment of nutritional status is an essential part of the investigation of all patients with IBD and deficiency should be actively sought.■Any patient with macro- or micronutrient deficiency should be referred for dietetic assessment.■Micronutrient deficiency (most frequently iron, vitamin B12, folate and magnesium) should be replaced aggressively, parenterally if necessary.■Significant improvement in gastrointestinal symptoms can be achieved by low-residue diets (for stricturing disease) and (always under dietetic supervision) management of lactose and other intolerances.■Irritable bowel syndrome symptoms in patients with IBD can respond to low fermentable oligo-, di-, monosaccharide and polyol (FODMAP) diets, again this must be done under dietetic supervision.■Active Crohn's disease can be treated by exclusive enteral nutrition (elemental/polymeric/altered fat formulations all have equivalent efficacy).■Enteral nutrition can maintain remission in Crohn's disease and in this context can be given alongside normal oral intake.■Nutritional support does not have an established role in the treatment of active ulcerative colitis, other than in the management of malnutrition.■Total parenteral nutrition should not be used unless intestinal failure occurs.■There is insufficient evidence to support the routine use of Ω3 fish oil, prebiotics and glutamine in the treatment of active IBD.

Glutamine and whey protein improve intestinal permeability and morphology in patients with Crohn's disease: a randomized controlled trial

BACKGROUND

Increased intestinal permeability (IP) has been implicated in the etiopathogenesis, disease activity and relapse of Crohn's disease (CD). Glutamine, the major fuel for the enterocytes, may improve IP.

AIM

We evaluated the effect of oral glutamine on IP and intestinal morphology in patients with CD.

METHODS

In a randomized controlled trial, consecutive patients with CD in remission phase with an abnormal IP were randomized to a glutamine group (GG) or active control group (ACG) and were given oral glutamine or whey protein, respectively, as 0.5 g/kg ideal body weight/day for 2 months. IP was assessed by the lactulose mannitol excretion ratio (LMR) in urine, and morphometry was performed by computerized image analysis system.

RESULTS

Patients (age 34.5 ± 10.5 years; 20 males) were assigned to the GG (n = 15) or ACG (n = 15). Fourteen patients in each group completed the trial. The LMR [median (range)] in GG and ACG at 2 months was 0.029 (0.006-0.090) and 0.033 (0.009-0.077), respectively, with P = 0.6133. IP normalized in 8 (57.1%) patients in each group (P = 1.000). The villous crypt ratio (VCR) [mean (SD)] in GG and ACG at 2 months was 2.68 (1.02) and 2.49 (0.67), respectively, (P = 0.347). At the end of 2 months LMR improved significantly in GG from 0.071 (0.041-0.254) to 0.029 (0.006-0.090) (P = 0.0012) and in ACG from 0.067 (0.040-0.136) to 0.033 (0.009-0.077) (P = 0.0063). VCR improved in the GG from 2.33 (0.77) to 2.68 (1.02) (P = 0.001), and in ACG from 2.26 (0.57) to 2.49 (0.67) (P = 0.009).

CONCLUSIONS

Intestinal permeability and morphology improved significantly in both glutamine and ACG.

Glutamine supplementation in sick children: is it beneficial?

The purpose of this review is to provide a critical appraisal of the literature on Glutamine (Gln) supplementation in various conditions or illnesses that affect children, from neonates to adolescents. First, a general overview of the proposed mechanisms for the beneficial effects of Gln is provided, and subsequently clinical studies are discussed. Despite safety, studies are conflicting, partly due to different effects of enteral and parenteral Gln supplementation. Further insufficient evidence is available on the benefits of Gln supplementation in pediatric patients. This includes premature infants, infants with gastrointestinal disease, children with Crohn's disease, short bowel syndrome, malnutrition/diarrhea, cancer, severe burns/trauma, Duchenne muscular dystrophy, sickle cell anemia, cystic fibrosis, and type 1 diabetes. Moreover, methodological issues have been noted in some studies. Further mechanistic data is needed along with large randomized controlled trials in select populations of sick children, who may eventually benefit from supplemental Gln.

Glutamine therapy improves outcome of in vitro and in vivo experimental colitis models

BACKGROUND

Pharmacologic doses of glutamine (GLN) can improve clinical outcome following acute illness and injury. Recent studies indicate enhanced heat shock protein (HSP) expression is a key mechanism underlying GLN's protection. However, such a link has not yet been tested in chronic inflammatory states, such as experimental inflammatory bowel disease (IBD).

METHODS

Experimental colitis was induced in Sprague-Dawley rats via oral 5% dextran sulfate sodium (DSS) for 7 days. GLN (0.75 g/kg/d) or sham was administered to rats by oral gavage during 7-day DSS treatment. In vitro inflammatory injury was studied using YAMC colonic epithelial cells treated with varying concentrations of GLN and cytokines (tumor necrosis factor-α/interferon-γ).

RESULTS

Pharmacologic dose, bolus GLN attenuated DSS-induced colitis in vivo with decreased area under curve for bleeding (8.06 ± 0.87 vs 10.38 ± 0.79, P < .05) and diarrhea (6.97 ± 0.46 vs 8.53 ± 0.39, P < .05). This was associated with enhanced HSP25 and HSP70 in colonic mucosa. In vitro, GLN enhanced cell survival and reduced proapoptotic caspase3 and poly(ADP-ribose) polymerase cleavage postcytokine injury. Cytokine-induced inducible nitric oxide synthase expression and nuclear translocation of nuclear factor-κB p65 subunit were markedly attenuated at GLN concentrations above 0.5 mmol/L. GLN increased cellular HSP25 and HSP70 in a dose-dependent manner.

CONCLUSIONS

These data demonstrate the therapeutic potential of GLN as a "pharmacologically acting nutrient" in the setting of experimental IBD. GLN sufficiency is crucial for the colonic epithelium to mount a cell-protective, antiapoptotic, and anti-inflammatory response against inflammatory injury. The enhanced HSP expression observed following GLN treatment may be responsible for this protective effect.

Nutrition in inflammatory bowel disease

The diet of industrialized nations may contribute to the pathogenesis of both ulcerative colitis (UC) and Crohn disease (CD). Malnutrition is relatively unusual in UC, but in CD, which often affects the small intestine, it is frequent and may be severe. Nutrition support is therefore frequently indicated. First principles of artificial nutrition can be applied effectively using the gut whenever possible. Parenteral nutrition is generally required only in those with short bowel syndrome. An increasing literature (especially in pediatrics) favors the use of defined exclusive enteral nutrition (EN) in the primary treatment of active CD. Controlled trials are, however, lacking, and recommendations are accordingly not of the highest rank. It appears that in this context, simple polymeric regimens are usually sufficient, and there is currently insufficient evidence to make a strong recommendation for disease-specific feeds. In the maintenance of remission in CD, controlled data demonstrate that defined EN reduces the risk of relapse requiring steroid treatment. There are no data in support of primary nutrition therapy in UC either in management of the acute flare or in maintenance. In conclusion, nutrition therapy in adults with inflammatory bowel disease is probably both undervalued and underused, but the evidence base needs to be strengthened to confirm its efficacy, determine better those patients most likely to benefit, and optimize the regimens to be employed.

Existing dietary guidelines for Crohn's disease and ulcerative colitis

Patients with inflammatory bowel disease (IBD) often question their doctors about diet. The objectives of this article are to provide clinicians with existing dietary advice by presenting the dietary information proposed by medical societies in the form of clinical practice guidelines as it relates to IBD; listing dietary guidelines from patient-centered IBD-related organizations; and creating a new 'global practice guideline' that attempts to consolidate the existing information regarding diet and IBD. The dietary suggestions derived from sources found in this article include nutritional deficiency screening, avoiding foods that worsen symptoms, eating smaller meals at more frequent intervals, drinking adequate fluids, avoiding caffeine and alcohol, taking vitamin/mineral supplementation, eliminating dairy if lactose intolerant, limiting excess fat, reducing carbohydrates and reducing high-fiber foods during flares. Mixed advice exists regarding probiotics. Enteral nutrition is recommended for Crohn's disease patients in Japan, which differs from practices in the USA.

Nutrition in pediatric inflammatory bowel disease

Nutrition interventions play a central role in the treatment and management of inflammatory bowel disease in children. Malnutrition is a common presenting symptom in both pediatric ulcerative colitis and Crohn's disease and is associated with increased morbidity. Providing macronutrients can improve growth; likewise, identifying and correcting micronutrient deficiencies can improve comorbid conditions like osteopenia and anemia. Although many patients manipulate their diets to help treat their inflammatory bowel disease, only parenteral nutrition with bowel rest and exclusive enteral nutrition therapy have been shown effective for the treatment of inflammatory bowel disease.

Nutritional consequences and nutrition therapy in Crohn's disease

75% of hospital patients with Crohn's disease (CD) suffer from malnutrition and one third of CD patients have a body mass index below 20. Inflammatory bowel diseases (IBD) patients have many vitamin and nutrient deficiencies which can lead to important consequences such as hyperhomocysteinemia which is associated with a higher risk of thromboembolic disease. Nutritional deficiencies in IBD patients are the result of insufficient intake, malabsorption and protein-losing enteropathy as well as the metabolic distubances directly induced by the chronic disease and its treatments, in particular corticosteroids. Screening for nutritional deficiencies in chronic disease patients is warranted. Managing the deficiencies involves simple nutritional guidelines, vitamin supplements, and nutritional support in the worst cases, in particular in children in order to limit the impact of IBD on growth. In active CD, enteral nutrition is the first line therapy in children and should be used as sole therapy in adults mainly when treatment with corticosteroids is not feasible.

Nutritional therapy for the treatment of pediatric Crohn's disease

Crohn's disease and ulcerative colitis are lifelong conditions with particular effects upon nutrition, especially in children and adolescents. Various therapies are available for these conditions but there remains no cure. Over the last decades, exclusive enteral nutrition (EEN) has been demonstrated to have efficacy in the induction of remission, along with numerous other nutritional and inflammatory benefits. This article reviews the benefits and outcomes associated with EEN in Crohn's disease. The potential mechanisms of this therapy are highlighted, along with factors that are barriers to the wider use of EEN.

Does evidence exist to include dietary therapy in the treatment of Crohn's disease?

Prescription drugs and surgery are two common medical therapies for Crohn's disease (CD), an inflammatory bowel disease that affects the GI tract. Unfortunately, certain drugs can cause serious side effects, and surgeries must often be repeated. No diet has been established to alleviate the pain and suffering of CD patients. This is curious given the fact that a higher prevalence of food sensitivities exist in this population of patients, and enteral nutrition is not only the first-line of therapy in Japan, but a known research method used to place the majority of CD patients into remission. Although not all patients respond equally to diet, many simply remove symptom-provoking foods, such as dairy, wheat, corn and certain fruits and vegetables. We suggest assisting these patients in their self-assessment of irritating and symptom-provoking foods by educating them in the use of a food-symptom diary followed by a customized elimination diet trialed for 2-4 weeks to determine if there is any benefit to the individual patient.

Potential for amino acids supplementation during inflammatory bowel diseases

The pathophysiology of inflammatory bowel diseases (IBDs) is multifactorial and involves interactions of gut luminal content with mucosal barrier and especially immune cells. Malnutrition is a frequent issue during IBD flares, especially in Crohn's disease (CD) patients, and nutritional support is frequently used to treat malnutrition but also in an attempt to modulate intestinal inflammation. The use of oral or enteral nutrition intervention in IBDs may be effective, alone or in combination with drugs, to achieve and maintain remission. However, standard diets are less effective than new-generation biotherapies and could be improved by supplementation with specific immunomodulatory amino acids. Experimental studies evaluating glutamine, the preferential substrate for enterocytes, are promising. Some clinical studies with oral glutamine in CD are until now disappointing, but new formulations and targeting could enhance glutamine efficacy at the site of mucosal lesions. The role of arginine, involved in nitric oxide and polyamines synthesis, still remains debated. However, the effects of these amino acids in IBD have been poorly documented in humans. Other candidates like glycine, cysteine, histidine, or taurine should also be evaluated in the future.

Systematic review of the evidence base for the medical treatment of paediatric inflammatory bowel disease

OBJECTIVE

To systematically review the evidence base for the medical (pharmaceutical and nutritional) treatment of paediatric inflammatory bowel disease.

METHODS

Key clinical questions were formulated regarding different treatment modalities used in the treatment of paediatric (not adult-onset) IBD, in particular the induction and maintenance of remission in Crohn disease and ulcerative colitis. Electronic searches were performed from January 1966 to December 2006, using the electronic search strategy of the Cochrane IBD group. Details of papers were entered on a dedicated database, reviewed in abstract form, and disseminated in full for appraisal. Clinical guidelines were appraised using the AGREE instrument and all other relevant papers were appraised using Scottish Intercollegiate Guidelines Network methodology, with evidence levels given to all papers.

RESULTS

A total of 6285 papers were identified, of which 1255 involved children; these were entered on the database. After critical appraisal, only 103 publications met our criteria as evidence on medical treatment of paediatric IBD. We identified 3 clinical guidelines, 1 systematic review, and 16 randomised controlled trials; all were of variable quality, with none getting the highest methodological scores.

CONCLUSIONS

This is the first comprehensive review of the evidence base for the treatment of paediatric IBD, highlighting the paucity of trials of high methodological quality. As a result, the development of clinical guidelines for managing children and young people with IBD must be consensus based, informed by the best-available evidence from the paediatric literature and high-quality data from the adult IBD literature, together with the clinical expertise and multidisciplinary experience of paediatric IBD experts.