Colonization of fecal microbiota from patients with neonatal necrotizing enterocolitis exacerbates intestinal injury in germfree mice subjected to necrotizing enterocolitis-induction protocol via alterations in butyrate and regulatory T cells

Abstract

Background Necrotizing enterocolitis (NEC) remains a life-threatening disease in neonates. Numerous studies have shown a correlation between the intestinal microbiota and NEC, but the causal link remains unclear. This study aimed to demonstrate the causal role of gut microbiota in NEC and explore potential mechanisms involved. Methods Eighty-one fecal samples from patients with NEC and eighty-one matched controls (matched to the NEC infants by gestational age, birth weight, date of birth, mode of delivery and feeding patterns) were collected. To explore if altered gut microbiota contributes to the pathogenesis of NEC, fecal microbiota transplantation (FMT) was carried out in germ-free (GF) mice prior to a NEC-induction protocol that included exposure to hypoxia and cold stress. Butyric acid was also administered to demonstrate its role in NEC. The fecal microbiota from patients and mice were analyzed by 16S rRNA gene sequencing analysis. Short chain fatty acid (SCFA) levels were measured by gas chromatography-mass spectrometry (GC–MS). The ontogeny of T cells and regulatory T cells (Tregs) in lamina propria mononuclear cells (LPMC) from the ileum of patients and mice were isolated and analyzed by flow cytometry.The transcription of inflammatory cytokines was quantified by qRT-PCR. Results NEC patients had increased Proteobacteria and decreased Firmicutes and Bacteroidetes compared to fecal control samples, and the level of butyric acid in the NEC group was lower than the control group. FMT in GF mice with samples from NEC patients achieved a higher histological injury scores when compared to mice that received FMT with control samples. Alterations in microbiota and butyrate levels were maintained in mice following FMT. The ratio of Treg/CD4+T (Thelper) cells was reduced in both NEC patients and mice modeling NEC following FMT. Conclusions The microbiota was found to have NEC and the microbial butyrate-Treg axis was identified as a potential mechanism for the observed effects.

Succinate aggravates intestinal injury in mice with necrotizing enterocolitis

“…Substantial evidence has indicated that succinate concentrations increase under conditions of hypoxia, stress, inflammation, and changes in intestinal microorganisms ( Nagao-Kitamoto et al., 2016 ; Macias-Ceja et al., 2019 ; Banerjee et al., 2020 ; Huber-Ruano et al., 2022 ). It has been widely reported in previous studies that changes in the intestinal flora are closely related to the development of NEC ( He et al., 2021 ; Liu et al., 2022a ; Samara et al., 2022 ). In exploring the pathological mechanism whereby the gut flora affects NEC, some investigators have proven that gut microbiota-derived metabolites, including short-chain fatty acids, DL-lactate, tauroursodeoxycholic acid, and other related metabolites, play important messenger roles in NEC progression or can contribute to its prediction ( Li et al., 2019a ; Feng et al., 2022 ; Huang et al., 2022 ).…”

β-glucan protects against necrotizing enterocolitis in mice by inhibiting intestinal inflammation, improving the gut barrier, and modulating gut microbiota

“…Lachnospiraceae is a protective commensal strain that produces short-chain fatty acids such as butyrate by fermentation of dietary fiber [ 78 ]. Recent research by He et al demonstrated that the administration of butyrate could reduce intestinal inflammation in NEC mice possibly via the induction of T reg [ 79 ]. We also found that β-glucan pretreatment can reduce the abundance of Klebsiella oxytoca g Klebsiella compared with the NEC group.…”

White Matter Injury in Preterm Infants: Pathogenesis and Potential Therapy From the Aspect of the Gut–Brain Axis

“…Microbiota-derived metabolites are the bridge of the microorganisms and the host since the changes of microbial metabolites reflect the variation of microbiota, environment, and host (Krautkramer et al, 2021). In spite of the complexity in the crosstalk of microbiota and host, knowledge of metabolites could provide a direct feature of the host-microbiota system as a whole, and the function of the microbiota had been explored in several neonatal diseases, such as necrotizing enterocolitis (NEC) (He et al, 2021;Renwick and Stewart, 2022) and bronchopulmonary dysplasia (Zhao et al, 2018). In the gut-brain axis, the metabolites released from microbiota also played an important role in myelination of prematurity.…”