Department of Gastroenterology, Central Clinical School, Monash University and Alfred Health, Melbourne, Victoria, Australia.
Aliment Pharmacol Ther. 2023 May;57(9):932-947. doi: 10.1111/apt.17451. Epub 2023 Mar 9.
Exclusive enteral nutrition (EEN) induces remission and mucosal healing in patients with Crohn's disease, but the mechanism of action remains unknown.
To outline current understanding of the mechanisms of action of EEN.
From a comprehensive literature search, published data were critically examined in a narrative review.
Multiple potential mechanisms of action have been identified. EEN optimises nutritional status. Differences in gut microbiota in terms of overall diversity and taxonomic community structure are observed between responders and non-responders to EEN. Therapy with EEN alters microbial metabolites (including faecal short-chain fatty acids, amino acids, branched-chain amino acids and sulphide) and faecal pH. Epithelial effects and restoration of barrier function, as well as changes in mucosal cytokine profiles and T-cell subsets are observed in responders to EEN. The impact of inclusion or exclusion of specific dietary components may be of importance, but putative detrimental components are found in many formulas. A major challenge in interpreting these findings is that they often contradict or change in opposite directions to what is considered 'beneficial'. It is difficult to differentiate between the observations following EEN being driven by EEN per se and those associated with resolving inflammation.
The mechanisms of action of EEN are likely to involve a complex interplay between host mucosal immune response and luminal environment, but the identity of key factors remains poorly understood. A better definition of pathogenic factors may aid in developing more targeted dietary treatment and provide insights into the pathogenesis of Crohn's disease.
肠内营养（EEN）可诱导克罗恩病患者缓解和黏膜愈合，但作用机制尚不清楚。
概述 EEN 作用机制的现有认识。
通过全面的文献检索，对发表的数据进行了叙述性综述的批判性检查。
已确定多种潜在的作用机制。EEN 可优化营养状况。EEN 应答者和非应答者的肠道微生物群在总体多样性和分类群结构方面存在差异。EEN 治疗可改变微生物代谢产物（包括粪便短链脂肪酸、氨基酸、支链氨基酸和硫化物）和粪便 pH 值。EEN 应答者可观察到上皮细胞效应和屏障功能的恢复，以及黏膜细胞因子谱和 T 细胞亚群的变化。包含或排除特定膳食成分的影响可能很重要，但许多配方中都存在潜在有害成分。解释这些发现的一个主要挑战是，它们经常与被认为“有益”的发现相矛盾或朝着相反的方向变化。很难区分 EEN 本身和缓解炎症相关的观察结果。
EEN 的作用机制可能涉及宿主黏膜免疫反应和腔环境之间的复杂相互作用，但关键因素的特征仍知之甚少。对致病因素的更好定义可能有助于开发更有针对性的饮食治疗，并深入了解克罗恩病的发病机制。
