Preoperative exclusive enteral nutrition (EEN) improves nutritional status, reduces intestinal inflammation, and likely improves surgical outcomes. Crohn\'s disease exclusion diet with partial enteral nutrition (CDED) also reduces intestinal inflammation but its safety preoperatively is unknown. This single-blinded, multicentre, randomised controlled trial of three preoperative nutritional therapies aimed to assess the feasibility of recruiting and retaining patients and collecting primary and secondary effectiveness outcomes. Adults undergoing elective Crohn\'s disease surgery with a body mass index (BMI) > 18.5 kg/m2 and without significant weight loss were eligible to participate. Patients were randomly assigned to six weeks of preoperative EEN, CDED, or standard care. Feasibility, nutritional, radiological, and surgical outcomes were recorded. Over 18 months, 48 patients were screened, 17 (35%) were randomised, and 13/17 (76%) patients were retained in the intervention phase. It was feasible to collect primary and secondary effectiveness data; at day 30, three patients had Clavien Dindo Grade 2 complications, and 10 had no complications. Nutritional therapy adherence of patients retained in the study was high. Recruitment and retention of patients who need elective Crohn\'s disease surgery for preoperative nutritional therapy is possible, although a shorter duration may improve EEN completion. The impact on surgical outcomes should be assessed in a larger study.

Crohn\'s disease (CD) is an inflammatory bowel disease. Previous research has explored the impact of diet on CD, as specific dietary components can influence gut microbiota and immune responses, contributing to damage in the gastrointestinal tract. The Crohn\'s Disease Exclusion Diet (CDED) is based on an exclusion diet; it is a recent dietary approach that is often used alongside partial enteral nutrition (PEN) and aims to induce disease remission by excluding certain dietary components. This study assesses the current evidence for the effectiveness of the CDED + PEN in achieving remission in both children and adults with active CD. Our systematic review followed PRISMA recommendations and was registered in PROSPERO with CRD number 42022335076. The searched databases were PubMed/MEDLINE, Cochrane Library, Scopus, and Web of Science. The included studies were analyzed using Rayyan software, and the risk of bias was assessed with Cochrane RevMan 5.0 software. The primary assessed outcome was clinical remission, evaluated with validated questionnaire scores such as PCDAI, CDAI, or HBI. All analyzed papers yielded promising results. Notably, the CDED + PEN demonstrated better tolerance than exclusive enteral nutrition (EEN), resulting in higher adherence rates. Therefore, the CDED + PEN appears to be a viable alternative for induction remission in active disease for both children and adults with CD.

Predicting response to exclusive enteral nutrition (EEN) in active Crohn\'s disease (CD) could lead to therapy personalization and pretreatment optimization.
This study aimed to explore the ability of pretreatment parameters to predict fecal calprotectin (FCal) levels at EEN completion in a prospective study in children with CD.
In children with active CD, clinical parameters, dietary intake, cytokines, inflammation-related blood proteomics, and diet-related metabolites, metabolomics and microbiota in feces, were measured before initiation of 8 wk of EEN. Prediction of FCal levels at EEN completion was performed using machine learning. Data are presented with medians (IQR).
Of 37 patients recruited, 15 responded (FCal < 250 μg/g) to EEN (responders) and 22 did not (nonresponders). Clinical and immunological parameters were not associated with response to EEN. Responders had lesser (μmol/g) butyrate [responders: 13.2 (8.63-18.4) compared with nonresponders: 22.3 (12.0-32.0); P = 0.03], acetate [responders: 49.9 (46.4-68.4) compared with nonresponders: 70.4 (57.0-95.5); P = 0.027], phenylacetate [responders: 0.175 (0.013-0.611) compared with nonresponders: 0.943 (0.438-1.35); P = 0.021], and a higher microbiota richness [315 (269-347) compared with nonresponders: 243 (205-297); P = 0.015] in feces than nonresponders. Responders consumed (portions/1000 kcal/d) more confectionery products [responders: 0.55 (0.38-0.72) compared with nonresponders: 0.19 (0.01-0.38); P = 0.045]. A multicomponent model using fecal parameters, dietary data, and clinical and immunological parameters predicted response to EEN with 78% accuracy (sensitivity: 80%; specificity: 77%; positive predictive value: 71%; negative predictive value: 85%). Higher taxon abundance from Ruminococcaceae, Lachnospiraceae, and Bacteroides and phenylacetate, butyrate, and acetate were the most influential variables in predicting lack of response to EEN.
We identify microbial signals and diet-related metabolites in feces, which could comprise targets for pretreatment optimization and personalized nutritional therapy in pediatric CD.

Exclusive enteral nutrition (EEN) is an established dietary treatment for Crohn\'s disease (CD) by alleviating inflammation and inducing remission. However, the mechanisms of action of EEN are incompletely understood. As CD is associated with gut microbiome dysbiosis, we investigated the effect of EEN on the microbiome in a rat model of CD-like colitis. The rat model of CD-like colitis was established by an intracolonic instillation of TNBS at 65 mg/kg in 250 µL of 40% ethanol. Sham control rats were instilled with saline. Rats were fed ad libitum with either regular pellet food or EEN treatment with a clear liquid diet (Ensure). Rats were euthanized at 7 days. Fecal pellets were collected from the distal colon for 16S rRNA sequencing analysis of gut microbiota. In addition, colon tissues were taken for histological and molecular analyses in all the groups of rats. EEN administration to TNBS-induced CD rats significantly improved the body weight change, inflammation scores, and disease activity index. The mRNA expression of IL-17A and interferon-γ was significantly increased in the colonic tissue in TNBS rats when fed with regular food. However, EEN treatment significantly attenuated the increase in IL-17A and interferon-γ in TNBS rats. Our 16S rRNA sequencing analysis found that gut microbiota diversity and compositions were significantly altered in TNBS rats, compared to controls. However, EEN treatment improved alpha diversity and increased certain beneficial bacteria such as Lactobacillus and Dubosiella and decreased bacteria such as Bacteroides and Enterorhabdus in CD-like rats, compared to CD-like rats with the regular pellet diet. In conclusion, EEN treatment increases the diversity of gut microbiota and the composition of certain beneficial bacteria. These effects may contribute to the reduced inflammation by EEN in the rat model of CD-like colitis.

BACKGROUND: Exclusive enteral nutrition (EEN) is an important alternative strategy for patients with Crohn\'s disease (CD), and during this process, microbiota alterations have been observed. However, the underlying mechanisms by which EEN reduces intestinal inflammation are currently unclear.
METHODS: The therapeutic potential of enteral nutrition (EN) was assessed using various mouse models. Fecal full-length 16S rDNA sequencing analysis and several CD metagenome datasets were used to identify the candidate therapeutic bacteria Faecalibaculum rodentium (F. rodentium). Whole genome sequencing of F. rodentium and widely-targeted metabolome analysis of the supernatant showed that EN-induced F. rodentium accumulation protected against colitis via histidine biosynthesis.
RESULTS: The therapeutic potential of EN therapy was observed in both dextran sulfate sodium (DSS)-induced colitis and Il10-/- spontaneous colitis mouse models. Accumulation of F. rodentium after EN therapy was determined using full-length 16S rDNA sequencing and verified with several metagenome datasets from patients with CD. Colonization of an isolated F. rodentium could reduce colitis in Il10-/- mice. Significant histidine enrichment was observed in the F. rodentium culture supernatant, and a series of histidine biosynthesis genes were observed in the F. rodentium genome. Engineered Escherichia coli Nissle 1917 (EcN), encoding the heterologous hisG of F. rodentium (EcN-hisG), which was a key driver of histidine biosynthesis in F. rodentium, was found to protect against colitis.
CONCLUSIONS: This study suggests that EN-induced F. rodentium accumulation protects against colitis in mice via gut bacteria-mediated histidine biosynthesis.
BACKGROUND: A full list of funding bodies can be found in the Acknowledgements section.

BACKGROUND: Adalimumab monotherapy can suppress gut inflammation and induce remission in active Crohn\'s disease but has some limitations. Exclusive enteral nutrition (EEN) is recommended for patients with mild to moderate Crohn\'s disease (CD), but implementation is challenging.
OBJECTIVE: To evaluate the effectiveness of adalimumab combined with partial enteral nutrition (PEN) in the induction therapy for Crohn\'s disease.
METHODS: A prospective cohort study was designed and a total of 56 patients with active CD who met the criteria for enteral nutrition (EN) treatment in our hospital were selected. The baseline data of all patients were collected including age, sex and other general information. The changes in fecal calprotectin, C-reactive protein (CRP), albumin(Alb), hemoglobin (Hb), platelets (Plt), erythrocyte sedimentation rate (ESR), Crohn\'s disease activity index score (CDAI), simple endoscopic score (SES-CD) and body mass index (BMI) were compared between the adalimumab combined with enteral nutrition (ADA+EN) group (N = 37) the adalimumab group (ADA) (N = 19) at week 0 (W0) and treatment outcomes at week 12(W12). Additionally, the differences between the two groups before and after treatment were evaluated. Then the ADA+EN group was divided into an adalimumab combined with exclusive enteral nutrition subgroup (ADA+EEN) and an adalimumab combined with partial nutrition subgroup (ADA+PEN) according to enteral nutrition intake. The changes in fecal calprotectin, CRP, Alb, Hb, Plt, ESR and CDAI, SES-CD and BMI were compared between the  ADA+EEN group and the ADA+PEN group at week 0 (W0) and treatment outcomes at week 12(W12). The differences between the two groups before and after treatment were evaluated. To evaluate the effectiveness of the two treatments on patients\' quality of life, nutritional recovery and body composition, patients in the ADA+EN group were needed to complete the Inflammatory Bowel Disease Questionnaire (IBDQ), EQ-5D-5L, the EuroQol visual analogue scale (EQ-VAS) and body composition analysis.A total of 28 patients completed all questionnaires and body composition analyses at week 0 and week 12, including 10 patients in the ADA+EEN group and 18 patients in the ADA+PEN group, respectively. The differences of in IBDQ, EQ-5D-5L and body composition analysis were compared between the two groups at week 0 (W0) and treatment outcomes at week 12(W12). Additionally, the differences between the two groups before and after treatment were evaluated.
RESULTS: These investigated indexes such as calprotectin, Hb, Plt, ESR, Alb, BMI, CRP, CDAI and SES-CD scores were significantly different before and after treatment  in the ADA+EN group (p < 0.01). However, fecal calprotectin, Hb, SES-CD scores and Alb in the ADA group were not statistically significantly different from W0 to W12 (p > 0.05). The fecal calprotectin and CDAI scores in the ADA+EN group were significantly lower than those in the ADA group after treatment. The differences in all factors before and after treatment between the ADA+PEN group and the ADA+EEN group were statistically significant (p < 0.05). However, there was no significant difference between the two groups at week 12 (p > 0.05).
CONCLUSIONS: Adalimumab combined with EN are more effective than ADA monotherapy in terms of endoscopy and clinical remission. By comparing the investigated indicators such as calprotectin, Hb, Plt, ESR ,CRP and SES-CD scores, it was proven that adalimumab combined with partial enteral nutrition or exclusive enteral nutrition has the same remission effect in induced Crohn\'s disease. The combination of biological agents and partial nutrition can improve medical order compliance, psychological burden and quality of life. Therefore, adalimumab combined with partial nutrition can be used as the first-line treatment for CD induced remission.

UNASSIGNED: Exclusive enteral nutrition (EEN) therapy effectively induces remission in pediatric Crohn\'s disease (CD). However, this may depend on the type of enteral formula used. Moreover, data on the efficacy of amino acid-based EEN are limited. Thus, we aimed to prospectively evaluate the efficacy of amino acid-based formulas for EEN in pediatric patients with active CD.
UNASSIGNED: Patients with active CD aged between 6 and 17 years were recruited into this prospective study from four hospitals in China between March 2019 and December 2021. Patients received EEN for 8 weeks. Inflammatory and nutrition-associated indices were evaluated at 0, 4, and 8 weeks after treatment. Paired t-tests and Wilcoxon signed-rank tests were used to compare continuous and categorical variables before and after intervention, respectively.
UNASSIGNED: Twenty-four patients were included in the analysis. After an 8-week intervention period, the CD activity index significantly decreased (26.3 ± 12.2 vs 7.1 ± 8.3, P < 0.001). Most patients (66.7%) achieved complete clinical remission. Among the 22 patients who had ulcers and erosions diagnosed endoscopically at baseline, 10 (45.5%) achieved complete mucosal healing. The degree of thickening of the intestinal wall was significantly reduced after EEN intervention, with a transmural healing rate of 42.9%. Furthermore, the serum inflammatory markers decreased and there was a significant improvement in the nutrition-related indices (P < 0.05). There were no severe adverse effects.
UNASSIGNED: Amino acid-based EEN is effective and safe for treating pediatric-onset CD. Studies with larger sample sizes and mechanistic and follow-up studies are required to further validate these findings.

OBJECTIVE: The efficacy and underlying mechanisms of exclusive enteral nutrition (EEN) in adult patients with Crohn\'s disease (CD) remain controversial. This study aimed to evaluate the role of EEN in adult patients with CD and to explore the mechanisms from the perspective of immunoregulation.
METHODS: This is a prospective, open-label pilot study. Active patients with CD were enrolled and prescribed an amino-acid-rich elemental diet for 12 weeks. Dynamic changes in immune cells, including neutrophils, monocytes, T cells and B cells, were detected by flow cytometry. Plasma cytokines were evaluated by ELISA.
RESULTS: Twenty adult patients with CD were enrolled. Among them, 1 discontinued treatment due to poor compliance, and 19 patients were included for final analysis. Clinical remission was achieved in 47.37% (9/19), 63.16% (12/19), and 73.68% (14/19) patients at weeks 4, 8, and 12, respectively. Endoscopic remission and transmural healing were achieved in 52.63% (10/19) and 15.79% (3/19) patients at week 12. Notably, there was no significant difference in clinical remission between week 4 and week 8 (p = 0.33) or week 12 (p = 0.09). Furthermore, we observed a rapid reconstitution of immunologic homeostasis as early as week 4. At week 4, both the frequency and activation of neutrophils and monocytes were decreased after EEN therapy. Significant decreases in Th17 cells and naïve B cells, increases in memory B cells, and regulatory B cells were also detected. These changes remained stable at weeks 8 and 12.
CONCLUSIONS: EEN with an amino-acid-rich elemental diet orchestrated immunological balances and induces clinical remission in adult CD patients as early as week 4, suggesting a 4-week EEN therapy may be feasible and practicable in clinical practice.

Exclusive enteral nutrition (EEN) with fiber-free diets is an effective steroid-sparing treatment to induce clinical remission in children with Crohn\'s disease (CD). However, the mechanism underlying the beneficial effects of EEN remains obscure. Using a model of microbiota-dependent colitis with the hallmarks of CD, we find that the administration of a fiber-free diet prevents the development of colitis and inhibits intestinal inflammation in colitic animals. Remarkably, fiber-free diet alters the intestinal localization of Mucispirillum schaedleri, a mucus-dwelling pathobiont, which is required for triggering disease. Mechanistically, the absence of dietary fiber reduces nutrient availability and impairs the dissimilatory nitrate reduction to ammonia (DNRA) metabolic pathway of Mucispirillum, leading to its exclusion from the mucus layer and disease remission. Thus, appropriate localization of the specific pathobiont in the mucus layer is critical for disease development, which is disrupted by fiber exclusion. These results suggest strategies to treat CD by targeting the intestinal niche and metabolism of disease-causing microbes.

BACKGROUND: Partial enteral nutrition (PEN) coupled with the Crohn\'s disease (CD) exclusion diet (CDED) was shown to be effective in inducing clinical remission in paediatric CD. There are currently no robust data on the endoscopic outcomes of PEN. The aim of this study was to evaluate the clinical and endoscopic rates of remission after PEN combined with a modified CDED (mCDED) adjusted to the local cuisine in comparison with exclusive enteral nutrition (EEN) for the induction of remission.
METHODS: Between June 2017 and February 2021, a prospective cohort study on children with active CD, treated with PEN + mCDED or EEN, was performed at a single tertiary centre.
RESULTS: During the study period, 54 patients were screened and 15 were excluded according to the exclusion criteria, with six patients excluded in the first two days due to intolerance of the enteral formula. Fourteen patients were included in the PEN and 19 in the EEN group. They were assessed at Weeks 0, 1, 3 and 6, using clinical and laboratory parameters. Endoscopy was performed at Weeks 0 and 6. Clinical remission rates per protocol analysis were 84.6% in the PEN group and 81.3% in the EEN group (p = 0.99). At Week 6, an endoscopic response (a decline in the Simple Endoscopic Score for CD (SES-CD) > 50%) was observed in 84.6% of patients on PEN and in 68.8% on EEN treatment (p = 0.41). Endoscopic remission (SES-CD ≤ 2) was achieved in 53.8% of patients in the PEN group and in 50.0% in the EEN group (p = 0.99), while the mucosal healing rates (SES-CD = 0) were 38.5% with PEN and 43.8% with EEN (p = 0.99). A significant decline in the clinical and endoscopic activity scores was observed in both groups.
CONCLUSIONS: Our study suggests that PEN + mCDED could be effective in inducing endoscopic remission and mucosal healing in active paediatric CD patients. Here, we present an analysis of the data from our cohort of patients and our real-world experience with PEN + mCDED.