Exploring Different Effects of Exclusive Enteral Nutrition (EEN) and Corticosteroids on the Gut Microbiome in Crohn’s Disease Based on a Three-Stage Strategy

Enteral nutrition compared with corticosteroids in children with Crohn's disease: A long-term nationwide study from the epi-IIRN

BACKGROUND

Both corticosteroids and exclusive enteral nutrition (EEN) have been used as induction therapy in children with Crohn's disease (CD).

AIM

To compare in a nationwide study the long-term outcomes of children with CD receiving either EEN or corticosteroids as induction therapy.

METHODS

We retrieved data of all children diagnosed with CD (2005-2020) from the epi-IIRN cohort covering 98% of the Israeli population. The primary outcome was time to complicated disease course (i.e., surgery, steroid-dependency, or at least 2 biologic class). Patients were matched individually utilising propensity score adjustments.

RESULTS

We included 410 children treated with EEN and 375 with corticosteroids without other treatments (median follow-up, 4.73 [IQR: 2.2-7.2] years [1433 patient-years]). For 274 matched children, the probability of a complicated course was higher with corticosteroids than EEN at 0.5, 3 and 5 years (14% vs. 4%, 42% vs. 27% and 54% vs. 41%, respectively, p = 0.0066), despite similar use of biologics. Steroid-dependency (10% vs. 2%, 15% vs. 3%, and 20% vs. 5%, respectively, p = 0.00018), and hospitalisations (20% vs. 11%, 37% vs. 26%, and 55% vs. 38%, respectively, p = 0.002) were higher with corticosteroids. During follow-up, children receiving corticosteroids as induction treatment were more often further exposed to corticosteroids, and those on EEN were more often further exposed to nutritional treatment (p < 0.001). Induction with EEN had no advantage over corticosteroids regarding survival probability of surgeries, biologic use and growth.

CONCLUSIONS

EEN in paediatric CD is associated with lower long-term risks of corticosteroid dependency and hospitalisation than corticosteroids. These results may lend support to favouring nutritional therapy in paediatric CD.

Exclusive Enteral Nutrition Beneficially Modulates Gut Microbiome in a Preclinical Model of Crohn's-like Colitis

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.

Inflammation and malnutrition in inflammatory bowel disease

Inflammatory bowel disease (IBD), which includes Crohn's disease and ulcerative colitis, has become increasingly prevalent worldwide in the past decade. The nutritional status of patients with IBD is often impaired, with malnutrition presenting as imbalanced energy or nutrient intake, including protein-energy malnutrition, disease-related malnutrition, sarcopenia, and micronutrient deficiency. Additionally, malnutrition can manifest as overweight, obesity, and sarcopenic obesity. Malnutrition can lead to disturbances in gut microbiome composition that might alter homoeostasis and cause a dysbiotic state, potentially triggering inflammatory responses. Despite the clear link between IBD and malnutrition, little is known about the pathophysiological mechanisms beyond protein-energy malnutrition and micronutrient deficiencies that could promote inflammation through malnutrition, and vice versa. This Review focuses on potential mechanisms that trigger a vicious cycle between malnutrition and inflammation, and their clinical and therapeutic implications.