A randomized controlled study comparing elemental diet and steroid treatment in Crohn's disease

Can we improve the management of inoperable malignant bowel obstruction? Results of a feasibility study of elemental diet as an alternative to parenteral nutrition in patients with advanced gynaecological cancer

PURPOSE

Nutrition support in inoperable bowel obstruction (IBO) remains challenging. Parenteral nutrition (PN) is recommended if the prognosis is > 2 months. An elemental diet (ED) is licensed for strictures in Crohn's disease but has not been used in malignant bowel obstruction. The aim of this study was to evaluate the use of ED in patients with IBO and provide a proof of concept of ED as an acceptable feeding option.

METHODS

This was a mixed-methods single-arm feasibility study. The primary endpoint was to provide a 'proof of concept' of ED as an acceptable feeding option for patients with IBO. Secondary endpoints included taste acceptability, incidences of vomiting and pain, the proportion of women who tolerated ED, the number of cartons drunk, quality of life (QOL) and the number of women treated with chemotherapy. Patients (> 18 years) with CT-confirmed IBO who could tolerate 500 ml of liquid in 24 h remained on the trial for 2 weeks.

RESULTS

A total of 29 patients were recruited; of those, 19 contributed to the analysis for the primary endpoint; 13 (68.4%) participants tolerated the ED; 26 patients contributed to MSAS and EORTC QLQ questionnaires at baseline to allow for the assessment of symptoms. At the start of the study, 18 (69%) of patients experienced vomiting, reducing to 4 (25%) by the end of day 15 of the study; 24 (92%) of patients reported pain at consent, reducing to 12 (75%) by the end of day 15. QOL scores improved from 36.2 (95% CI 27.7-44.7) at baseline to 53.1 (95% CI 40.3-66) at the end of day 15; 16 (84%) participants commenced chemotherapy within the first week of starting ED. The number of cartons across all participants showed a median of 1.3 cartons per day (range 0.8 to 2.5).

CONCLUSION

ED is well tolerated by patients with IBO caused by gynaecological malignancies and may have a positive effect on symptom burden and QOL.

Clinical and Nutritional Impact of a Semi-Elemental Hydrolyzed Whey Protein Diet in Patients with Active Crohn's Disease: A Prospective Observational Study

Background: Malnourishment is a common complication in patients with Crohn’s disease. Methods: An observational, prospective study was conducted to assess the nutritional status, disease activity, and stool frequency at baseline and after 12 weeks of treatment with a semi-elemental diet in patients with active Crohn’s disease. Results: A total of 144 patients with Crohn’s disease were included. The nutritional status improved after treatment, resulting in 76.1% of patients at low risk of malnourishment, 20.4% moderately malnourished, and 8.5% severely malnourished after 12 weeks of treatment. Nutritional status improvement was associated with the number of nutritional supplements. Mean albumin levels and body mass index (BMI) improved after 12 weeks of nutritional treatment (from 3.0 g/dL to 3.7 g/dL and from 20.2 kg/m² to 21.1 kg/m², respectively). A significant decrease in HBI was found after 12 weeks of nutritional treatment (from 10.2 to 3.7). The mean number of stools per day decreased with the 12 week semi-elemental diet (from 4.6 stools/day to 1.7 stools/day). Conclusion: In this observational study, the semi-elemental diet seemed effective in improving the nutritional status, disease activity, and stool frequency in patients with active Crohn’s disease.

Exclusive enteral nutrition with oral polymeric diet helps in inducing clinical and biochemical remission in adults with active Crohn's Disease

BACKGROUND AND AIMS

Exclusive enteral nutrition (EEN) is not routinely used as induction therapy for adults with active Crohn's Disease (CD). The aim of this study was to assess the effectiveness of EEN with oral polymeric formula as an adjunct for inducing clinical and biochemical remission in adults with active CD.

METHODS

We performed a retrospective analysis of data from January 2018 to September 2019 on all patients with active CD who commenced EEN. Primary endpoint was clinical remission (CDAI ≤150) or response (100-point decrease in CDAI) at 8 weeks. Secondary endpoint was achievement of biochemical remission (CRP ≤5 mg/L or faeces calprotectin ≤150 mcg/g) at 8 weeks in those whose baseline values were elevated. We also aimed to identify predictors of response to EEN therapy.

RESULTS

Sixty-six patients commenced EEN, 53/66 (80.3%) completed the prescribed EEN course. At 8 weeks, 42/66 (63.6%) patients achieved primary endpoint and secondary endpoint was achieved in 30/53 (56.6%) of patients. Patients receiving EEN for ≥ 6 weeks achieved primary (72% vs 47.8%, OR 2.8, p = 0.047, CI 0.97 -8.16) and secondary endpoint (67.6% vs 36.8%, OR 3.58, p = 0.035, CI 1.1- 11.63) more frequently when compared with patients who received EEN for <6 weeks. Nine patients reported adverse effects (4 nausea,3 diarrhoea,1 constipation and 1 abdominal pain), none of whom ceased therapy.

CONCLUSION

Polymeric EEN is well tolerated, safe and effective in inducing clinical and biochemical remission in adults with active CD. EEN duration of ≥ 6 weeks has better outcomes. This article is protected by copyright. All rights reserved.

Review of exclusive enteral therapy in adult Crohn's disease

Background

Exclusive enteral nutrition (EEN) is a potentially effective but underused therapy for Crohn’s disease (CD) in adults. It is first-line induction treatment for paediatric patients but remains a second-line or third-line therapy in adults.

Objective

To analyse the evidence for EEN in adult patients with CD, and summarise this in a narrative review.

Methods

In April/May 2020 and July 2021, a literature search was performed using the Medical Subject Headings (MeSH) terms: ‘Crohn’s disease’, ‘CD’, ‘inflammatory bowel disease’, ‘IBD’, ‘exclusive enteral nutrition’, ‘enteral nutrition’, ‘EEN’, in PubMed, Scopus, Cochrane. Additional studies were obtained from references of search result articles as well as general reading. Studies with adult patients with CD treated with EEN were selected. 79 articles of relevance were found. Where data in adults were lacking, data from paediatric studies as extrapolated with care.

Results

EEN in adult patients been shown to improve clinical, biomarker, endoscopic and radiologic measures of disease activity. EEN avoids the potential adverse effects of recurrent corticosteroids for induction such as metabolic derangements and opportunistic infections. EEN has also demonstrated benefits among adult patients with fistulising and stricturing CD. It may avoid surgery in such patients. Preoperative EEN has also been shown to reduce postoperative complications and recurrence. There appears to be benefits in combing EEN with antitumour necrosis factor agents, however, benefits of combination therapy with other biologics are less clear. A major drawback of EEN therapy in adults has been poor compliance. More palatable polymeric formulations improved patient education and dietitian support may overcome this. Evidence in adults is limited to small studies, often with suboptimal control arms and lack of blinding. Larger scale studies with improved study design are needed to confirm these beneficial effects.

Conclusion

Despite limitations in evidence EEN should be considered in treating adults with CD.

Nutritional Treatment in Crohn's Disease

Crohn's disease (CD) is a chronic inflammatory bowel disease (IBD) which can affect any part of the whole gastrointestinal tract (from mouth to anus). Malnutrition affects 65-75% of CD patients, and it is now well acknowledged that diet is of paramount importance in the management of the disease. In this review, we would like to highlight the most recent findings in the field of nutrition for the treatment of CD. Our analysis will cover a wide range of topics, from the well-established diets to the new nutritional theories, along with the recent progress in emerging research fields, such as nutrigenomics.

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.

Effect of fat composition in enteral nutrition for Crohn's disease in adults: A systematic review

BACKGROUND & AIMS

The role of enteral nutrition (EN) fat composition in regulating inflammation in Crohn's disease (CD) is not clear. There is, moreover, insufficient evidence to guide the choice of EN in CD with any confidence. We have reanalysed the findings of previous studies in a systematic review focussing on the relationship between EN fat content and remission rates (RR).

METHODS

A systematic search with no language restriction was undertaken in Medline and Embase databases supplemented by a manual search in the reference lists of identified studies. The selection criteria were: clinical trial, exclusive EN, adults and CD. Data on the type of EN, its fat composition, achieved RR, and study design were extracted. An established assessment tool was used to assess the quality of the studies.

RESULTS

A total of 29 clinical trials are included in this review. The quality of the studies was highly variable. No fewer than 27 formulations of enteral feed were identified including 4 elemental and 23 non-elemental preparations. There was a positive correlation between the total n-6 fatty acid content and response rates, which was significant when expressed as the ratio between n-6 and n-3 fatty acids (r = 0.378, p = 0.018). A non-significant positive trend was founded (r = 0.072; p = 0.643) between medium chain triglycerides (MCT) delivery as a percentage of the total energy provision and RR. While a non-significant negative trend was reported for the delivery of monounsaturated fatty acids (MUFA) (r = -0.23, p = 0.13). A qualitative advantage to regimens based on safflower oil suggest that optimised therapeutic approaches are within reach.

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.

Feeding an Elemental Dietvsa Milk-Based Formula Does Not Decrease Intestinal Mucosal Growth in Infant Pigs

BACKGROUND

We previously showed that the level of enteral nutrient intake determines the rate of intestinal growth in piglets. Our objective was to determine whether providing enteral nutrition in the form of elemental nutrients (glucose, amino acids, lipid [ED]) rather than cow's milk formula (lactose, protein, lipid [FORM]) reduces small intestinal growth and lactase activity.

METHODS

Three-week-old piglets were fed either ED (n = 7) intragastrically or FORM (n = 6) orally for 6 days.

RESULTS

Intestinal protein and DNA masses, villus height, and crypt depth were not different in ED and FORM pigs. Crypt cell proliferation, measured by in vivo bromodeoxyuridine labeling, was significantly (p < .05) higher (+37%) in ED than in FORM pigs. Rates of mucosal protein synthesis (%/d), measured by in vivo 2H-leucine incorporation, were higher (p < .05) in ED than FORM (147 vs 89) pigs. Circulating concentrations (pmol/L) of the intestinotrophic peptide, glucagon-like peptide-2 (GLP-2), were also higher (p < .05) in ED than in FORM (148 vs 87) pigs. The mean lactase-specific activity (micromol/min/g) in proximal and distal segments was higher (p < .05) in FORM than in ED (124 vs 58) pigs.

CONCLUSIONS

We conclude that intestinal mucosal growth and villus morphology are similar in pigs fed ED and FORM, despite higher cell proliferation and protein synthesis rates and lower lactase activity with ED. This implies that elemental diets may be as trophic as polymeric formulas to simultaneously provide nutrition and a stimulus for intestinal growth during bowel rest.

Therapeutic Efficacy of Oral Enteral Nutrition in Pediatric Crohn's Disease: A Single Center Non-Comparative Retrospective Study

PURPOSE

Exclusive enteral nutrition (EEN) therapy effectively induces clinical remission in Crohn's disease (CD). It remains unclear, however, whether partial enteral nutrition (PEN) can maintain remission. This study was performed to determine the abilities of oral EEN and oral PEN to induce and maintain clinical remission in pediatric patients with CD, respectively.

MATERIALS AND METHODS

Pediatric patients with CD who received oral EEN at a single center in 2000-2014 were identified retrospectively. Remission rates of the EEN and PEN during the 2 years study period were determined. Risk factors for EEN and PEN failure were identified.

RESULTS

Of the 66 patients who started EEN, 61 (92%) completed the course. Clinical remission was achieved in 88% (58/66) of the patients. All 58 patients with remission continued with PEN: 43 (74%) were treatment adherent. The cumulative remission rates at 1 and 2 years were 67% and 52%, respectively. Differing from EEN, limited therapeutic efficacy of PEN was shown in severe CD patients. Female gender associated significantly with non-adherence.

CONCLUSION

Oral EEN and PEN effectively induced and maintained remission in a pediatric population. Non-adherence was a limiting factor in the success of therapy.

Nutritional and health benefits of semi-elemental diets: A comprehensive summary of the literature

AIM: To critically review and summarize the literature on nutritional and health outcomes of semi-elemental formulations on various nutritionally vulnerable patient populations who are unable to achieve adequate nutrition from standard oral diets.

METHODS: We conducted a comprehensive literature search of Pubmed and Embase databases. We manually screened articles that examined nutritional and health outcomes (e.g., growth, disease activity, gastrointestinal impairment, mortality, and economic impact) among various patient groups receiving semi-elemental diets. This review focused on full-text articles of randomized controlled clinical trials and other intervention studies, but pertinent abstracts and case studies were also included. Results pertaining primarily to tolerance, digestion, and absorption were summarized for each patient population in this systematic review.

RESULTS: Results pertaining primarily to tolerance, digestion, and absorption were summarized for each patient population. The efficacy of semi-elemental whey hydrolyzed protein (WHP) diet have been reported in various nutritionally high risk patient populations including - Crohn’s disease, short bowel syndrome, acute and chronic pancreatitis, cerebral palsy, cystic fibrosis, cerebrovascular accidents, human immunodeficiency virus, critically ill, and geriatrics. Collectively, the evidence from the medical literature indicates that feeding with a semi-elemental diet performs as well or better than parenteral or amino acid based diets in terms of tolerance, digestion, and nutrient assimilation measures across various disease conditions.

CONCLUSION: Based on this comprehensive review of the literature, patient populations who have difficulty digesting or absorbing standard diets may be able to achieve improved health and nutritional outcomes through the use of semi-elemental WHP diets.

Preoperative optimization of crohn disease

Crohn disease is a chronic disease that is treated with aminosalicylates, antibiotics, and immunosuppressant agents. Most patients ultimately require surgical intervention and many will require additional surgery for recurrent disease. Consequently, surgery is generally performed only when medical management fails; however, these patients are often malnourished and immunosuppressed. Preoperative optimization is necessary to minimize morbidity, including intra-abdominal septic complications and anastomotic leaks. In this article, the authors review some considerations to improve the surgical outcome in Crohn disease.

Enteral nutrition in Crohn's disease: an underused therapy

This paper reviews the literature on the history, efficacy, and putative mechanism of action of enteral nutrition for inflammatory bowel disease in both paediatric and adult patients. It also analyses the reasoning behind the low popularity of exclusive enteral nutrition in clinical practice despite the benefits and safety profile.

Use of exclusive enteral nutrition in adults with Crohn’s disease: A review

Exclusive enteral nutrition (EEN) is well-established as a first line therapy instead of corticosteroid (CS) therapy to treat active Crohn’s disease (CD) in children. It also has been shown to have benefits over and above induction of disease remission in paediatric populations. However, other than in Japanese populations, this intervention is not routinely utilised in adults. To investigate potential reasons for variation in response between adult studies of EEN and CS therapy. The Ovid database was searched over a 6-mo period. Articles directly comparing EEN and CS therapy in adults were included. Eleven articles were identified. EEN therapy remission rates varied considerably. Poor compliance with EEN therapy due to unpalatable formula was an issue in half of the studies. Remission rates of studies that only included patients with previously untreated/new CD were higher than studies including patients with both existing and new disease. There was limited evidence to determine if disease location, duration of disease or age of diagnosis affected EEN therapy outcomes. There is some evidence to support the use of EEN as a treatment option for a select group of adults, namely those motivated to adhere to an EEN regimen and possibly those newly diagnosed with CD. In addition, the use of more palatable formulas could improve treatment compliance.

Evidence-based clinical practice guidelines for Crohn's disease, integrated with formal consensus of experts in Japan

Crohn's disease is a disorder of unknown etiology and complicated pathogenesis. A substantial amount of evidence has accumulated recently and has been applied to clinical practice. The present guidelines were developed based on recent evidence and the formal consensus of experts relevant to this disease. Here we provide an overview of these guidelines, as follows. Target disease: Crohn's disease Users: Clinical practitioners in internal medicine, surgery, gastroenterology, and general practice Purpose: To provide appropriate clinical indicators to practitioners Scope of clinical indicators: Concept of Crohn's disease, epidemiology, classifications, diagnosis, treatment, follow up, and special situations Intervention: Diagnosis (interview, physical examination, clinical laboratory tests, imaging, and pathology) and treatment (lifestyle guidance, drug therapy, nutritional therapy, surgery, etc.) Outcome assessment: Attenuation of symptoms, induction and maintenance of remission, imaging findings, quality of life (QOL), prevention of complications and harm of therapy Methods for developing these guidelines: Described in the text Basis of recommendations: Integration of evidence level and consensus of experts Cost-benefit analysis: Not implemented Evaluation of effectiveness: Yet to be confirmed Status of guidelines: Updated version of the first Guidelines published in 2010 Publication sources: Printed publication available and electronic information in preparation Patient information: Not available Date of publication: October 2011 These guidelines were intended primarily to be used by practitioners in Japan, and the goal of these guidelines is to improve the outcomes of patients with Crohn's disease.

DHA supplemented in peptamen diet offers no advantage in pathways to amyloidosis: is it time to evaluate composite lipid diet?

Numerous reports have documented the beneficial effects of dietary docosahexaenoic acid (DHA) on beta-amyloid production and Alzheimer's disease (AD). However, none of these studies have examined and compared DHA, in combination with other dietary nutrients, for its effects on plaque pathogenesis. Potential interactions of DHA with other dietary nutrients and fatty acids are conventionally ignored. Here we investigated DHA with two dietary regimes; peptamen (pep+DHA) and low fat diet (low fat+DHA). Peptamen base liquid diet is a standard sole-source nutrition for patients with gastrointestinal dysfunction. Here we demonstrate that a robust AD transgenic mouse model shows an increased tendency to produce beta-amyloid peptides and amyloid plaques when fed a pep+DHA diet. The increase in beta-amyloid peptides was due to an elevated trend in the levels of beta-secretase amyloid precursor protein (APP) cleaving enzyme (BACE), the proteolytic C-terminal fragment beta of APP and reduced levels of insulin degrading enzyme that endoproteolyse beta-amyloid. On the contrary, TgCRND8 mice on low fat+DHA diet (based on an approximately 18% reduction of fat intake) ameliorate the production of abeta peptides and consequently amyloid plaques. Our work not only demonstrates that DHA when taken with peptamen may have a tendency to confer a detrimental affect on the amyloid plaque build up but also reinforces the importance of studying composite lipids or nutrients rather than single lipids or nutrients for their effects on pathways important to plaque development.

Importance of disrupted intestinal barrier in inflammatory bowel diseases

The current paradigm of inflammatory bowel diseases (IBD), both Crohn's disease (CD) and ulcerative colitis (UC), involves the interaction between environmental factors in the intestinal lumen and inappropriate host immune responses in genetically predisposed individuals. The intestinal mucosal barrier has evolved to maintain a delicate balance between absorbing essential nutrients while preventing the entry and responding to harmful contents. In IBD, disruptions of essential elements of the intestinal barrier lead to permeability defects. These barrier defects exacerbate the underlying immune system, subsequently resulting in tissue damage. The epithelial phenotype in active IBD is very similar in CD and UC. It is characterized by increased secretion of chloride and water, leading to diarrhea, increased permeability via both the transcellular and paracellular routes, and increased apoptosis of epithelial cells. The main cytokine that seems to drive these changes is tumor necrosis factor alpha in CD, whereas interleukin (IL)-13 may be more important in UC. Therapeutic restoration of the mucosal barrier would provide protection and prevent antigenic overload due to intestinal "leakiness." Here we give an overview of the key players of the intestinal mucosal barrier and review the current literature from studies in humans and human systems on mechanisms underlying mucosal barrier dysfunction in IBD.

N-3 polyunsaturated fatty acid diet therapy for patients with inflammatory bowel disease

BACKGROUND

N-3 polyunsaturated fatty acids (PUFA) are considered important pharmaconutrients for modulating mucosal immunity and therapeutic responses in patients with inflammatory bowel disease (IBD). We investigated the influence of diet therapy involving the use of an "n-3 PUFA food exchange table" (n-3DP) on the fatty acid composition of the erythrocyte membranes of IBD patients and its remission-maintaining effects.

METHODS

We analyzed the fatty acid composition of the erythrocyte membrane before and after n-3DP intervention in 20 initial-onset IBD patients who had not undergone any dietary intervention. We then analyzed it again and evaluated disease activity after 12-18 months intervention in 230 IBD patients (168 ulcerative colitis, 62 Crohn's disease; follow-up group) in whom n-3DP was introduced after remission had been achieved. The follow-up group was divided into remission and relapse groups.

RESULTS

In the 20 initial-onset patients, the mean n-3/n-6 ratio significantly increased after intervention (0.41 ± 0.16 versus 0.70 ± 0.20; P < 0.001). In the follow-up group the ratio in the remission group (n = 145) was significantly higher than that in the relapse group (n = 85) (0.65 ± 0.28 versus 0.53 ± 0.18; P < 0.001). The ratio significantly decreased in those who suffered a relapse after the beginning of treatment (P < 0.01).

CONCLUSIONS

N-3DP significantly increased the erythrocyte membrane n-3/n-6 ratio in IBD patients, and this ratio was significantly higher in the remission group, suggesting that n-3DP alters the fatty acid composition of the cell membrane and influences clinical activity in IBD patients.

Clinical trial: normal diet vs. partial replacement with oral E028 formula for the prevention of gastrointestinal toxicity in cancer patients undergoing pelvic radiotherapy

BACKGROUND

Acute gastrointestinal symptoms affect 90% of patients during pelvic radiotherapy. Elemental diet is protective in animal models. A nonrandomized study suggested benefit from a partial elemental diet. A pilot study suggested that radiotherapy patients only tolerate oral elemental diet comprising one-third of total calories for 3 weeks.

AIM

To assess the feasibility and efficacy of replacing one-third of normal diet with elemental diet during the first 3 weeks of pelvic radiotherapy in reducing acute gastrointestinal toxicity.

METHODS

Patients were randomized to elemental diet or no intervention. Toxicity was assessed using the Inflammatory Bowel Disease Questionnaire, Vaizey Incontinence scale and Radiation Therapy Oncology Group tool. Faecal calprotectin measured intestinal mucosal inflammation.

RESULTS

Twenty-nine women and 21 men, median age 61.5 years were randomized. Patients taking elemental diet did not have lower gastrointestinal toxicity ratings or inflammatory markers (P > 0.2). The mean dose taken was 21% (2-36%) of total caloric requirements.

CONCLUSIONS

Patients cannot tolerate large volumes of oral elemental diet. The quantities consumed in this study produced no therapeutic benefit. Future studies should aim to replace a higher proportion of nutritional intake for a longer duration of radiotherapy treatment.

Polymeric formula has direct anti-inflammatory effects on enterocytes in an in vitro model of intestinal inflammation

Exclusive enteral nutrition using polymeric formula (PF) is a well-established therapeutic option for active Crohn's disease; however, its mechanisms of action are unknown. We investigated the anti-inflammatory effects of PF in an in vitro model of epithelial cell inflammation. PF did not affect cell viability over a range of dilutions, but when PF was added to the culture medium the interleukin (IL)-8 response to proinflammatory stimuli was significantly reduced. This effect was due to PF acting directly on the cells as the IL-8 response was still reduced when PF was separated from the proinflammatory stimuli in a 2-compartment system. In the presence of PF, nuclear factor (NF)-kappaB nuclear migration was not inhibited; however, IkappaBalpha degradation was delayed. PF has direct anti-inflammatory effects upon immortalized colonic enterocytes. Therefore PF may, in part, modulate gut inflammation by directly reducing the inflammatory response of the intestinal epithelium.

Serum lipopolysaccharide-binding protein in endotoxemic patients with inflammatory bowel disease

BACKGROUND

In inflammatory bowel disease (IBD), enhanced inflammatory activity in the gut is thought to increase the risk of bacterial translocation and endotoxemia. By searching for signs of endotoxin-signaling cascade activation, including augmented levels of endotoxin, lipopolysaccharide-binding protein (LBP), and soluble CD14 receptor (sCD14), this prospective study sought to establish whether endotoxemia could contribute to greater clinical activity of disease.

METHODS

Concentrations of plasma endotoxin, LBP, sCD14, several cytokines, acute phase proteins and clinical activity indices were determined in 104 patients with Crohn's disease (CD) and 52 patients with ulcerative colitis (UC).

RESULTS

Endotoxemia was present in 48% of the patients with CD and in 28% of the patients with UC. The mean LBP was higher in patients with active CD (23.1 +/- 13.7 microg/mL) and UC (21.4 +/- 10.9 microg/mL) than in healthy controls (7.2 +/- 1.8 microg/mL; P < 0.01). Elevated serum concentrations of endotoxin and LBP were even detected in patients with inactive CD. Among the patients with active IBD, those with higher endotoxin levels had the worst clinical activity scores and the highest LBP levels. Treatment normalized LBP concentrations, from 29.1 +/- 13.0 to 15.2 +/- 7.3 microg/mL; (P < 0.05) in active CD and from 21.7 +/- 9.8 to 13.6 +/- 5.7 microg/mL; (P < 0.01) in active UC, along with normalizing endotoxin and sCD14 plasma concentrations.

CONCLUSIONS

Patients with IBD show increased serum levels of endotoxin, LBP and sCD14. This alteration correlates with disease activity, with normal levels recovered after treatment, although less completely in Crohn's disease, and parallels a rise in proinflammatory cytokines, suggesting a contribution of bacterial products to the inflammatory cascade in these patients.

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

BACKGROUND

The role of enteral nutrition in Crohn's disease is controversial. Increasing research on the mechanisms by which nutritional therapy improves the clinical well being of patients with Crohn's disease has led to novel formula design and trials comparing two different forms of enteral nutrition. This meta-analysis aims to provide an update on the existing effectiveness data for both corticosteroids versus enteral nutrition and for one form of enteral nutrition versus another for inducing remission of active Crohn's disease.

OBJECTIVES

To evaluate the effectiveness of exclusive enteral nutrition (EN) as primary therapy to induce remission in Crohn's disease and to examine the importance of formula composition on effectiveness.

SEARCH STRATEGY

Studies were selected using a computer-assisted search of the on-line bibliographic databases MEDLINE (1966-2006) and EMBASE (1984-2006), as well as the Science Citation Index on Web of Science. Additional citations were sought by manual search of references of articles retrieved from the computerized search, abstracts submitted to major gastroenterologic meetings and published in the journals: American Journal of Gastroenterology, Gut, Gastroenterology, Journal of Pediatric Gastroenterology and Nutrition, and Journal of Parenteral and Enteral Nutrition, and from the reviewers' personal files or contact with leaders in the field.

SELECTION CRITERIA

All randomized and quasi-randomized controlled trials involving patients with active Crohn's disease defined by a clinical disease activity index were considered for review. Studies evaluating the administration of one type of enteral nutrition to one group of patients and another type of enteral nutrition or conventional corticosteroids to the other group were selected for review.

DATA COLLECTION AND ANALYSIS

Data were extracted independently by two authors and any discrepancies were resolved by rereading and discussion. For the dichotomous variable, achievement of remission, individual and pooled trial statistics were calculated as odds ratios (OR) with 95% confidence intervals (CI); both fixed and random effect models were used. The results for each analysis were tested for heterogeneity using the chi square statistic. The studies were separated into two groups: A. one form of enteral nutrition compared with another form of enteral nutrition and B. one form of enteral nutrition compared with corticosteroids. Subgroup analyses were conducted on the basis of clinical or disease criteria and formula composition. Sensitivity analyses were conducted on the basis of the inclusion of abstract publications, methodologic quality and by random or fixed effects models.

MAIN RESULTS

In part A, of the 15 included eligible trials (one abstract) comparing different formulations of EN for the treatment of active CD, 11 compared one (or more) elemental formula to a non-elemental one, three compared enteral diets of similar protein composition but different fat composition, and one compared non-elemental diets differing only in glutamine enrichment. Meta-analysis of ten trials comprising 334 patients demonstrated no difference in the efficacy of elemental versus non-elemental formulas (OR 1.10; 95% CI 0.69 to 1.75). Subgroup analyses performed to evaluate the different types of elemental and non-elemental diets (elemental, semi-elemental and polymeric) showed no statistically significant differences. Further analysis of seven 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 statistically significant difference in efficacy (OR 1.13; 95% CI 0.63 to 2.01). Similarly, the effect of very low fat content (< 3 g/1000 kCal) or type of fat (long chain triglycerides) were investigated, but did not demonstrate a difference in efficacy in the treatment of active CD, although a non significant trend was demonstrated favoring very low fat and very low long chain triglyceride content. This result should be interpreted with caution due to statistically significant heterogeneity and small sample size. Sensitivity analyses had no significant effects on the results. The role of specific fatty acids or disease characteristics on response to therapy could not be evaluated. In part B, eight trials (including two abstracts) comparing enteral nutrition to steroid therapy met the inclusion criteria for review. Meta-analysis of six trials that included 192 patients treated with enteral nutrition and 160 treated with steroids yielded a pooled OR of 0.33 favouring steroid therapy (95% CI 0.21 to 0.53). A sensitivity analysis including the abstracts resulted in an increase in the number of participants to 212 in the enteral nutrition group and 179 in the steroid group but the meta-analysis yielded a similar result (OR 0.36; 95% CI 0.23 to 0.56). There were inadequate data from full publications to perform further subgroup analyses by age, disease duration and disease location.

AUTHORS' CONCLUSIONS

Corticosteroid therapy is more effective than enteral nutrition for inducing remission of active Crohn's disease as was found in previous systematic reviews. Protein composition does not influence the effectiveness of EN in the treatment of active CD. A non significant trend favouring very low fat and/or very low long chain triglyceride content exists but larger trials are required to explore the significance of this finding.

Effectiveness of an 'half elemental diet' as maintenance therapy for Crohn's disease: A randomized-controlled trial

BACKGROUND

Although thiopurines have a proven role in maintenance therapy for Crohn's disease, an alternative therapy is needed for patients intolerant or resistant to thiopurines.

AIM

To evaluate the effectiveness of home enteral nutrition as a maintenance therapy regimen in which half of the daily calorie requirement is provided by an elemental diet and the remaining half by a free diet. We refer to this home enteral nutrition therapy as 'half elemental diet'.

METHODS

Between 2002 and 2005, 51 patients in remission from two hospitals were randomly assigned to a half elemental diet group (n = 26) or a free diet group (n = 25). The primary outcome measure of this study was the occurrence of relapse over the 2-year period.

RESULTS

The relapse rate in the half elemental diet group was significantly lower [34.6% vs. 64.0%; multivariate hazard ratio 0.40 (95% CI: 0.16-0.98)] than that in the free diet group after a mean follow-up of 11.9 months. Compliance was similar in the two groups. No adverse event occurred in any of the patients throughout the study.

CONCLUSION

This randomized-controlled trial shows the effectiveness of an half elemental diet, which is a promising maintenance therapy for Crohn's disease patients.

Traitements nutritionnels au cours des MICI :où en est-on ?

Protein-energy malnutrition and specific nutrient deficiencies are common in inflammatory bowel diseases (IBD), more particularly in Crohn's disease. In adults, the use of artificial nutrition is indicated in the event of malnutrition, short bowel syndrome, or IBD refractory to all other treatments. In children, enteral nutrition has a place as first-line treatment to avoid side effects of corticosteroids on growth. The use, as a therapeutic tool, of specific nutrients (n-3 fatty acids, glutamine, antioxydant vitamins and minerals, TGF-beta, probiotics...) seems interesting at the pathophysiological level. Nevertheless, these nutrients are still under evaluation and there are not enough available studies to recommend them in clinical routine. A very promising solution is the use of probiotics for the treatment of refractory pouchitis.

Interventions for growth failure in childhood Crohn's disease

BACKGROUND

Crohn's disease in childhood is a chronic relapsing condition. Fifteen to forty per cent of children with Crohn's disease have growth retardation (Griffiths 1993a). Some treatment modalities including corticosteroids have been implicated in growth failure but it is thought mainly to be secondary to uncontrolled disease activity (Motil 1993; Markowitz 1993). Growth is fundamental to the practice of pediatrics, so by taking growth as the primary outcome measure we address issues important to both patients, their families and pediatricians.

OBJECTIVES

To evaluate the effectiveness of the different modalities available for the treatment of childhood Crohn's disease with regard to the reversal of growth failure and the promotion of normal growth.

SEARCH STRATEGY

Searches were made of the following databases using the Collaborative Review Group Search Strategy: EMBASE (1984-2004), MEDLINE (1966-2004), The Cochrane Central Register of Controlled Trials, The Cochrane Inflammatory Bowel Disease and Functional Bowel Disorders Group Specialized Trials Register and the Science Citation Index. Abstracts from the major gastrointestinal research meetings and references from published articles were also reviewed.

SELECTION CRITERIA

Randomized controlled trials pertaining to children less than 18 years of age with Crohn's disease were selected. Those with growth as an outcome measure were included in the review.

DATA COLLECTION AND ANALYSIS

Data extraction and assessment of the methodological quality of each trial was independently reviewed by two reviewers. Only one good quality randomized controlled trial was included in the review and therefore no statistical analysis was possible.

MAIN RESULTS

Three randomized controlled trials were identified. One was of good methodological quality (Markowitz 2000). This study looked at the use of 6-mercaptopurine (6-MP) as a steroid sparing agent. No difference in linear growth was observed between the intervention and placebo groups, although the total steroid dose received over the 18 month follow up period was reduced in the group receiving 6-MP. The two remaining randomized controlled trials (Sanderson 1987; Thomas 1993a) consider the use of enteral feeding versus corticosteroids for induction of remission, with height velocity standard deviation score at 6 months as an outcome measure. Although of less rigorous methodological quality, the results of these studies are discussed in detail in the review. In both studies height velocity standard deviation scores were significantly increased in the enteral feeding group compared with the corticosteroid group.

AUTHORS' CONCLUSIONS

In addition to these randomized controlled trials, a body of lower quality evidence does exist relevant to two other important interventions; the use of supplemental enteral nutrition (Morin 1980; Belli 1988; Israel 1995) and the judicious use of surgical interventions in pre-pubertal children with refractory disease (Alperstein 1985; Lipson 1990; McLain 1990). Newer treatments, such as infliximab, are now becoming more widely used and may offer advantages in promoting growth. These effects are as yet unstudied. This review highlights the need for large, multi centre studies of the different treatment options in paediatric Crohn's disease and the importance of standardised measurements of growth, such as height velocity standard deviation scores and height standard deviation scores as outcome measures.

Mechanism of TNF-{alpha} modulation of Caco-2 intestinal epithelial tight junction barrier: role of myosin light-chain kinase protein expression

TNF-alpha plays a central role in the intestinal inflammation of various inflammatory disorders including Crohn's disease (CD). TNF-alpha-induced increase in intestinal epithelial tight junction (TJ) permeability has been proposed as one of the proinflammatory mechanisms contributing to the intestinal inflammation. The intracellular mechanisms involved in the TNF-alpha-induced increase in intestinal TJ permeability remain unclear. The purpose of this study was to investigate the possibility that the TNF-alpha-induced increase in intestinal epithelial TJ permeability was regulated by myosin light-chain kinase (MLCK) protein expression, using an in vitro intestinal epithelial model system consisting of the filter-grown Caco-2 intestinal epithelial monolayers. TNF-alpha (10 ng/ml) produced a time-dependent increase in Caco-2 MLCK expression. The TNF-alpha increase in MLCK protein expression paralleled the increase in Caco-2 TJ permeability, and the inhibition of the TNF-alpha-induced MLCK expression (by cycloheximide) prevented the increase in Caco-2 TJ permeability, suggesting that MLCK expression may be required for the increase in Caco-2 TJ permeability. The TNF-alpha increase in MLCK protein expression was preceded by an increase in MLCK mRNA expression but not an alteration in MLCK protein degradation. Actinomycin-D prevented the TNF-alpha increase in MLCK mRNA expression and the subsequent increase in MLCK protein expression and Caco-2 TJ permeability, suggesting that the increase in MLCK mRNA transcription led to the increase in MLCK expression. The TNF-alpha increase in MLCK protein expression was also associated with an increase in Caco-2 MLCK activity. The cycloheximide inhibition of MLCK protein expression prevented the TNF-alpha increase in MLCK activity and Caco-2 TJ permeability. Moreover, inhibitors of MLCK, Mg(2+)-myosin ATPase, and metabolic energy prevented the TNF-alpha increase in Caco-2 TJ permeability, suggesting that the increase in MLCK activity was required for the TNF-alpha-induced opening of the Caco-2 TJ barrier. In conclusion, our results indicate for the first time that 1) the TNF-alpha increase in Caco-2 TJ permeability was mediated by an increase in MLCK protein expression, 2) the increase in MLCK protein expression was regulated by an increase in MLCK mRNA transcription, and 3) the increase in Caco-2 TJ permeability required MLCK protein expression-dependent increase in MLCK activity.

Dietary fat attenuates the benefits of an elemental diet in active Crohn's disease: a randomized, controlled trial

OBJECTIVES

Although an elemental diet has been established as the primary treatment for patients with Crohn's disease, the influence of dietary fat on the elemental diet remains unclear. We have designed the first randomized, controlled trial for elemental diets containing different fat percentages in patients with active Crohn's disease.

METHODS

Each patient was randomized to receive one of three dose levels of fat in an elemental diet (Elental) for 4 weeks: 10 patients received low fat (3.06 g/day), 10 patients received medium fat (16.56 g/day) and eight patients received high fat (30.06 g/day). The additional fat was composed of long-chain fatty acids. All patients were evaluated using the International Organization of Inflammatory Bowel Disease rating, plus C-reactive protein level and erythrocyte sedimentation rate, which were measured at weekly intervals.

RESULTS

Although the International Organization of Inflammatory Bowel Disease rating, C-reactive protein level and erythrocyte sedimentation rate in the low-fat group decreased, the values in the medium- and high-fat groups fluctuated during the study. The remission rate after 4 weeks in each group was 80%, 40% and 25% for patients in the low-, medium- and high-fat groups, respectively.

CONCLUSIONS

When the fat consisted of long-chain triglycerides, a high amount of this fat in the elemental diet formula decreased its therapeutic effect against active Crohn's disease.

Effect of steroids on energy expenditure and substrate oxidation in women with Crohn's disease

OBJECTIVE

Patients with Crohn's disease (CD) have increased energy expenditure and fat oxidation. Steroids, commonly used to treat flare-up of CD, induce weight gain. This study was designed to evaluate the effects of prednisone and budesonide on energy expenditure and substrate oxidation in patients with CD.

METHODS

Twenty-nine women with CD and 10 healthy controls were studied. Ten patients received prednisone (0.75-1.0 mg/kg/day), nine received budesonide (9 mg/ day), and 10 did not receive steroids. Resting energy expenditure and substrate oxidation were measured by indirect calorimetry in a fasting state and after a standard diet.

RESULTS

In the fasting state, resting energy expenditure was higher in patients without steroids than in the controls. Lipid oxidation was lower (p < 0.01) in patients with prednisone (0.46 +/- 0.39 mg/kg/min) than in patients with budesonide (0.97 +/- 0.28 mg/kg/min) and without steroids (1.06 +/- 0.32 mg/kg/min), but was similar with control subjects (0.47 +/- 0.20 mg/kg/min). Postprandially, lipid oxidation was lower (p < 0.01) in patients with prednisone (0.32 +/- 0.23 mg/kg/min) than in patients with budesonide (0.75 +/- 0.20 mg/kg/min), without steroids (0.82 +/- 0.23 mg/kg/min), and controls (0.58 +/- 0.15 mg/kg/min). Protein oxidation was significantly higher in patients with prednisone than in the other subjects.

CONCLUSIONS

In women with CD, prednisone decreases lipid oxidation and increases protein oxidation. These effects are not observed with budesonide and may contribute to the weight gain and side effects commonly observed with prednisone. A low-fat/high-protein diet could be proposed during a course of prednisone.

Anti-tumor necrosis factor treatment restores the gut barrier in Crohn's disease

OBJECTIVES

A primary defect of the tight junctions and, hence, increased intestinal epithelial permeability has been proposed as a basic pathogenic event in Crohn's disease. Challenge of the mucosal immune system by the commensal gut flora would then result in chronic inflammation. Alternatively, increased permeability could be the result of inflammation. Our aim was to study intestinal permeability in refractory Crohn's disease before and after treatment with monoclonal chimeric antibodies directed against tumor necrosis factor (TNF) to investigate whether the abnormal permeability persists after control of inflammation.

METHODS

Twenty-three patients with active Crohn's disease were evaluated before and 4 wk after a single infusion of 5 mg/kg infliximab. Intestinal permeability was studied by measurement of urinary excretion of 51Cr-EDTA after oral intake.

RESULTS

The increased permeation of 51Cr-EDTA through the small intestine (1.63% interquartile range [IQR] 1.06-2.07) and the overall permeation (3.27% IQR 2.40-4.38) before therapy decreased significantly after infliximab infusion to values (1.04% IQR 0.74-1.54 and 2.42% IQR 2.03-2.80, respectively) in the range of those found in normal volunteers (1.12% IQR 0.85-1.58 and 2.28% IQR 1.88-2.86, respectively).

CONCLUSION

Inhibiting the proinflammatory cytokine tumor necrosis factor dramatically reduces gut inflammation and largely restores the gut barrier in Crohn's disease. Our data confirm the central role of TNF in gut barrier modulation in inflammatory conditions in vivo.

Fine and ultrafine particles of the diet: influence on the mucosal immune response and association with Crohn's disease

Crohn's disease is a modern Western disease characterised by transmural inflammation of the gastrointestinal tract. It is of unknown aetiology, but evidence suggests that it results from a combination of genetic predisposition and environmental factors. Bacterial-sized microparticles (0.1-1.0 microm) are potent adjuvants in model antigen-mediated immune responses and are increasingly associated with disease. Microparticles of TiO2 and aluminosilicate accumulate in macrophages of human gut-associated lymphoid tissue where the earliest signs of lesions in Crohn's disease are observed. Dietary microparticles are of endogenous or exogenous origin. Endogenous microparticles dominate and are calcium phosphate (most probably hydroxyapatite), which precipitates in the lumen of the mid-distal gastrointestinal tract due to secretion of Ca and phosphate in the succus entericus. Exogenous dietary microparticles are contaminants (soil and/or dust) and food additives. TiO2, for example, is a food colourant, and aluminosilicates are anti-caking agents, although some aluminosilicates occur as natural contaminants. Food additives alone account for ingestion of approximately 10(12) particles/person per d. Possible mechanisms for the role of exogenous and endogenous dietary microparticles in promoting toleragenic or immune responses of gastrointestinal mucosal phagocytosis are discussed. In a double-blind randomised pilot study we have shown that a diet low in Ca and exogenous microparticles appears to alleviate the symptoms of ileal Crohn's disease, with a significant (P= 0.002) improvement in the Crohn's disease activity index. A multi-centre trial and further mechanistic studies at the cellular level are underway.

Modification of enteral diets in inflammatory bowel disease

The provision of food is thought to promote the maintenance of gut integrity. Nutrients are able to elicit and affect both systemic and mucosal immune responses. Enteral diet therapy has long been known to be efficacious in inflammatory bowel disease (IBD), particularly in childhood Crohn's disease. However, the mechanisms of action of these diets are not clear. Nutritional repletion, direct effects on the gut mucosa or decreased intestinal permeability have all been postulated as being important in nutritional therapy. There is some evidence that the enteral diet has a direct effect on the gut mucosa by reducing cytokine production and the accompanying inflammation, thus leading to decreased intestinal permeability. Modifications of enteral diet composition have been evaluated in many studies. Such modifications include fat and/or protein content and the addition of bioactive peptides. The fatty acid composition of the enteral diet seems to have a much greater impact on its efficacy than modification of the N source. As specific fatty acids are precursors of inflammatory mediators derived from arachidonic acid, the reduction in these components may be beneficial in nutritional therapy for IBD. Addition of bioactive peptides to enteral diet formulas may also have a role; such peptides may have specific growth factor or anti-inflammatory actions. There is still much work to be done to define disease-specific enteral diet formulas that are effective as therapies for both Crohn's disease and ulcerative colitis.

Efficacy of treatment with chimeric monoclonal antibody (Infliximab) to tumor necrosis factor-alpha for Crohn's disease in Japan: evaluation by rapid turnover proteins, and radiologic and endoscopic findings

BACKGROUND

Several studies have reported that the chimeric monoclonal antibody to tumor necrosis factor (TNF)-alpha (Infliximab) is extremely valuable in the treatment of Crohn's disease. The aim of this study was to clarify the efficacy of this treatment in Japanese patients with Crohn's disease.

METHODS

A 12-week multicenter, open trial of Infliximab was carried out and involved 25 patients with moderate to severe Crohn's disease who were resistant to conventional treatment. Patients received a single 2-h intravenous infusion of Infliximab at a dose of 1, 3, 5 or 10 mg/kg bodyweight. Clinical evaluation of this treatment response was defined as a reduction in the index of the inflammatory bowel disease (IOIBD) and of the Crohn's disease activity index scores (CDAI), and in serum levels of C-reactive protein (CRP) at 2, 4, 8 and 12 weeks, and as an increase in serum levels of rapid turnover proteins as well as improvement of radiologic and endoscopic findings at 4 weeks.

RESULTS

The IOIBD score was reduced after 4 weeks in 66.7% of the group receiving 1 mg/kg Infliximab, 71.4% in the group receiving 3 mg/kg, 80.0% in the group receiving 5 mg/kg, and 85.7% in the group receiving 10 mg/kg. Improvement was better maintained over 12 weeks in the 5 and 10 mg/kg groups compared with the 1 and 3 mg/kg groups. Similar results were obtained for the CDAI scores. Serum levels of rapid turnover proteins significantly increased to within the normal ranges after infusion in all groups. Seven of the 11 (63.6%) patients evaluated showed improvement of radiologic and endoscopic findings.

CONCLUSIONS

A single infusion of Infliximab was effective for the treatment of Japanese patients with Crohn's disease. Serum rapid turnover proteins reflected the clinical response to antibody for TNF-alpha well.

Efficacy and tolerability of a low microparticle diet in a double blind, randomized, pilot study in Crohn's disease

BACKGROUND

Ultrafine and fine particles are potent adjuvants in antigen-mediated immune responses, and cause inflammation in susceptible individuals. Following recent findings that microparticles accumulate in the phagocytes of intestinal lymphoid aggregates, this study is the first investigation of whether their reduction in the diet improves the symptoms of Crohn's disease.

METHODS

In a double blind study, 20 patients with active corticosteroid-treated ileal or ileo-colonic Crohn's disease randomly received either a low microparticle diet (trial group; n = 10) or a control diet (n = 10) for 4 months. Crohn's disease activity index (CDAI) and corticosteroid requirements were compared.

RESULTS

One patient in each group was withdrawn. In the trial group there was a progressive decrease in CDAI from entry (392 +/- 25) to month 4 (145 +/- 47) (P = 0.002 vs control group) and seven patients were in remission (CDAI <150). In contrast, the control group had returned to baseline levels (302 +/- 28 on entry and 295 +/- 25 at month 4), with none in remission. Corticosteroid intake was reduced more in the trial group although this did not reach significance.

CONCLUSIONS

A low microparticle diet may be effective in the management of ileal Crohn's disease and could explain the efficacy of elemental diets, which similarly are low in microparticles.

Enteral nutritional therapy for inducing remission of Crohn's disease

BACKGROUND

The role of enteral nutrition in Crohn's disease is controversial. Increasing research on the mechanisms by which nutritional therapy improves the clinical well being of patients with Crohn's disease has led to novel formula design and trials comparing two different forms of enteral nutrition. This systematic review aims to provide an update on the existing efficacy data for both corticosteroids versus enteral nutrition and for one form of enteral nutrition versus another for inducing remission of active Crohn's disease.

OBJECTIVES

To evaluate the efficacy of exclusive enteral nutrition as primary therapy to induce remission in Crohn's disease and to examine the importance of formula composition on efficacy.

SEARCH STRATEGY

Studies were selected using a computer-assisted search of the on-line bibliographic databases MEDLINE (1966-2000) and EMBASE (1984-2000), as well as the Science Citation Index on Web of Science. Additional citations were sought by manual search of references of articles retrieved from the computerized search, abstracts submitted to major gastroenterologic meetings and published in the journals: Gut, Gastroenterology, Journal of Pediatric Gastroenterology and Nutrition, and Journal of Parenteral and Enteral Nutrition, and from the reviewers' personal files or contact with leaders in the field.

SELECTION CRITERIA

All randomized and quasi-randomized controlled trials involving patients with active Crohn's disease defined by a clinical disease activity index were considered for review. Studies evaluating the administration of one type of enteral nutrition to one group of patients and another type of enteral nutrition or conventional corticosteroids to the other group were selected for review.

DATA COLLECTION AND ANALYSIS

Data were extracted independently by two reviewers and any discrepancies were resolved by rereading and discussion. For the dichotomous variable, achievement of remission, individual and pooled trial statistics were calculated as odds ratios (OR) with 95% confidence intervals (CI); both fixed and random effect models were used. The results for each analysis were tested for heterogeneity using the chi square statistic. The studies were separated into two groups: A. one form of enteral nutrition compared with another form of enteral nutrition and B. one form of enteral nutrition compared with corticosteroids. Subgroup analyses were conducted on the basis of clinical or disease criteria and formula composition. Sensitivity analyses were conducted on the basis of the inclusion of abstracts of studies not yet fully published, methodologic quality and by random or fixed effects models.

MAIN RESULTS

In part A, of the 11 trials (one abstract) comparing different formulations of enteral nutrition ten compared one [or more (Middleton (a)1995)] elemental formulas to a non-elemental diet. The eleventh study (Akobeng 2000) compared two non-elemental diets differing only by glutamine enrichment in one group. This study was therefore not included in the primary analysis but was part of the subgroup analyses. Meta-analysis of nine studies which included 170 patients treated with an elemental diet and 128 patients treated with a non-elemental diet for active Crohn's disease demonstrated no significant difference among diet formulations [OR 1.15 (95% CI: 0.64, 2.08)]. Significant heterogeneity was not present [chi-square 9.77 (df=8)]. Subgroup and sensitivity analyses had no significant effect on the results. In part B, six trials (two abstracts) comparing enteral nutrition to steroid therapy met the inclusion criteria for review. Meta-analysis of four trials that included 130 patients treated with enteral nutrition and 123 treated with steroids yielded a pooled OR of 0.30 favouring steroid therapy (95% CI: 0.17, 0.52). Heterogeneity was not demonstrated [chi-square 0.43 (df=3)]. The risk difference calculated from this meta-analysis was 0.26, and the NNT (number of patients needed to treat with steroids rather than enteral nutrition to achieve one remission) was four. The same result was found in a sensitivity analysis that included abstracts. The inclusion of abstracts resulted in an increase in the number of participants to 150 in the enteral nutrition group and 142 in the steroid group but the meta-analysis yielded a similar result [OR 0.34 (95% CI: 0.20, 0.56)]. There were inadequate data from full publications to perform further subgroup analyses by age, disease duration and disease location.

REVIEWER'S CONCLUSIONS

Corticosteroid therapy is more effective than enteral nutrition for inducing remission of active Crohn's disease as was found in past meta-analyses. There is no significant difference in the efficacy of elemental and non-elemental diets for induction of remission of Crohn's disease.