Polymeric versus elemental diet as primary treatment in active Crohn's disease: a randomized, double-blind trial

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.

Nutrition in inflammatory bowel disease

Nutritional derangements are frequent in inflammatory bowel disease. In the past year significant work has been published examining the mechanisms of impaired food intake in animal models of inflammatory bowel disease, which allow a better understanding of these processes. Data from the same laboratory have shed further light on the relative role of underfeeding and inflammation on the growth retardation associated with intestinal inflammation. Other studies have provided further data on the risk factors and predictive biomarkers of bone loss in patients with inflammatory bowel disease. The potential role of enteral nutrition as primary therapy for Crohn's disease is particularly addressed in this review. Recent contributions to the field emphasized the special importance of this modality of therapy in paediatric patients. The possible mechanisms for such a therapeutic action are not well understood. Other nutrients may have a therapeutic potential in inflammatory bowel disease. In particular, recent data on the in-vivo anti-inflammatory actions of butyrate merit special mention. Finally, novel nutritional therapeutic strategies for inflammatory bowel disease, such as transforming growth factor-beta2-enriched enteral feeding, or hydrothermally processed cereals have recently been explored.

Nutrition in inflammatory bowel disease: impact on disease and therapy

Nutritional derangements are frequent in inflammatory bowel disease. In the last year, significant work was published examining the mechanisms of impaired food intake in animal models of inflammatory bowel disease, which allow a better understanding of these processes. These data have shed new light on the relative role of underfeeding and inflammation on the growth retardation associated with intestinal inflammation. Other studies have provided further information on the risk factors and predictive biomarkers of bone loss in patients with inflammatory bowel disease. The potential role of enteral nutrition as primary therapy for Crohn disease is particularly addressed in the present review. Recent contributions emphasized the special importance of this therapeutic modality in pediatric patients, but the possible mechanisms for such therapeutic effect are still not well understood. Other nutrients may have a therapeutic potential in inflammatory bowel disease. In particular, recent data on the in vivo antiinflammatory action of butyrate merit special mention. Finally, novel nutritional therapeutic strategies for inflammatory bowel disease, such as transforming growth factor-beta2-enriched enteral feeding or hydrothermally processed cereals, have recently been explored.

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.

Review article: the management of severe Crohn's disease

The treatment of severe and active Crohn's disease is currently based on immunosuppression, but also involves the management of nutrition, appropriate selection of patients for surgery, and maintenance of remission in the long term. Corticosteroids remain the drug of the first choice, particularly in the acute setting. However, there is evolving understanding of the role of other immunosuppressants and immune modifiers, as major concerns regarding side-effects and efficacy of steroids in the medium to long-term drive the search for alternatives.

Enteral feeding and Crohn disease

Enteral nutrition is an established therapeutic option in the treatment of patients with Crohn disease. The mode of action for enteral nutrition remains unknown but research efforts have begun to elucidate the complex interaction between nutritional luminal contents, intestinal epithelium, and mucosal immune response. Trials of novel enteral diet formulations have been conducted to explore the antiinflammatory role of specific nutrients.

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.

Nutrition in inflammatory bowel disease

Recent developments concerning nutritional complications of inflammatory bowel disease include a better understanding of disease-associated anorexia and increasing recognition of the interaction of nutrition and cytokines in the pathogenesis of growth impairment of children. Decreased bone mineral density is a multifactorial complication and an increased focus of research. Enteral nutrition continues to play an important role in the therapy of Crohn's disease. The mechanisms whereby specific nutrients, such as n-3 fatty acids, antioxidants, and butyrate, ameliorate inflammation are being elucidated in in-vitro studies, but beneficial effects have yet to be translated into the clinical sphere.