Impact of cooking and species on intestinal fermentation patterns of vegetables in a humanized in vitro model of the gastro-intestinal tract

Obesity and associated pathologies have dramatic consequences on patients’lives as well as high societal costs. Because of the role of intestinal dysbiosis and microbiota make-up on the pathogenesis of obesity, several strategies such as eating prebiotics and dietary fibre supplements are being investigated to reshape the intestinal microbial communities of obese patients. Beyond supplement, dietary fibre is supplied through plant ingredients in the meals. In the framework of the multidisciplinary research project Food4Gut, the use of vegetables rich in specific targeted dietary fiber, namely fructans, is being scrutinized for its ability to induce positive changes in the intestinal ecophysiology. Because expected effect might differ according the content in dietary fibre and fructans, the soluble:insoluble ratio, as well as the cooking of the vegetables, the fermentation patterns of several vegetables are being investigated in an dual in vitro model combining enzymatic hydrolysis to an in vitro fermentation step using faecal inoculums from humans, to evaluate the performance of gut microbiota, modulation of metabolic functions. Six vegetables were sampled in triplicates (N=3) and steamed for 20 to 30 min.: Jerusalem artichoke, salsify, asparagus, pumpkin, fennel and swede. They were chosen because they display a variety of contents in fructans, soluble (SDF) and insoluble dietaryfibre (IDF). Steamed vegetable samplesand burgers from local fast food restaurants (negative control) were hydrolyzed in vitro why porcine pepsin and pancreatin to mimic digestion in the upper gut and indigested fiber residues were recover using a 6kDa dialysis membrane.Subsequently, in vitro fermentation is being run with independent fecal inoculums from obese and lean patients (N=4). Fermentation kinetics over 24h as well as short-chain fatty acid production and profiles will be compared according to the individual donor and the vegetable species and multivariate analysis will be used to explore the relationships between donor, vegetable species and composition and fermentation patterns.Projet Food4 gu

Hepatoprotective effects of crude rhubarbe extract extend to the modulation of gut microbiota in a murine acute alcohol-induced steato-hepatitis model

Binge drinking is emerging and alarming social and health problem, leading to alcoholic liver disease (ALD). It is characterized by hepatic steatosis coupled with inflammation. A way to limit the evolution of ALD would be the use of bioactive compounds to reduce fat accumulation and inflammation. A specific crude rhubarb extract has been tested in a murine model of acute alcohol-induced steato-hepatitis. 18 male C57BL/6J mice has been fed with a standard diet, enriched with (OH-EV1 group) or without the rhubarb extract (CT and OH groups) for 17 days. Groups OH and OH-EV1 were then submitted to binge drinking and euthanazed. Physiological parameters have been measured. Moreover, bacterial ceacal contents were analyzed by pyrosequencing and 16S rDNA v1-V3 targeted metagenomic analysis. Inflammatory markers levels in liver and total hepatic cholesterol level show that the standardized extract limits inflammation and lipid accumulation. Moreover, metagenomic analysis revealed the composition of major bacterial populations in caecum. Several populations were statistically influenced by the rhubarb enriched diet compared normal diet as shown after binge drinking. Among these populations, few were strongly correlated with the levels of inflammatory markers in the liver. We targeted 3 populations for further analysis : two Alistipes populations and Parabacteroides goldsteinii. The Alistipes belong to yet undescribed species. Based upon the only nucleic trace from pyrosequecing, 3 quantitative RT-PCR tests were created to target these populations in gut samples. Quantitative determination of these populations confirmed the statistical correlation with inflammatory markers and results from metagenomic study

Functional Effects of EPS-Producing Bifidobacterium Administration on Energy Metabolic Alterations of Diet-Induced Obese Mice

Obesity has been recognized by the World Health Organization as a global epidemic. The gut microbiota is considered as a factor involved in the regulation of numerous metabolic pathways by impacting several functions of the host. It has been suggested that probiotics can modulate host gene expression and metabolism, and thereby positively influence host adipose tissue development and obesity related-metabolic disorders. The aim of the present work was to evaluate the effect of an exopolysaccharide (EPS)-producing Bifidobacterium strain on host glucose and lipid metabolism and the gut microbial composition in a short-term diet-induced obesity (DIO) in mice. C57BL/6J male mice were randomly divided into three groups: a control group that received control standard diet, a group fed a high-fat diet (HF), and a group fed HF supplemented with Bifidobacterium animalis IPLA R1. Fasting serum insulin as well as triglycerides accumulation in the liver were significantly reduced in the group receiving B. animalis IPLA R1. The treatment with the EPS-producing B. animalis IPLA R1 tended to down-regulate the expression of host genes involved in the hepatic synthesis of fatty acids which was concomitant with an upregulation in the expression of genes related with fatty acid oxidation. B. animalis IPLA R1 not only promoted the increase of Bifidobacterium but also the levels of Bacteroides-Prevotella. Our data indicate that the EPS-producing Bifidobacterium IPLA R1 strain may have beneficial effects in metabolic disorders associated with obesity, by modulating the gut microbiota composition and promoting changes in lipids metabolism and glucose homeostasis

The potential role of the Dipeptidyl peptidase-4-like activity from the gut microbiota on the Host Health

The Dipeptidyl peptidase-4 (DPP-4) activity influences metabolic, behavioral and intestinal disorders through the cleavage of key hormones and peptides. Some studies describe the existence of human DPP-4 homologs in commensal bacteria, for instance in Prevotella or Lactobacillus. However, the role of the gut microbiota as a source of DPP-4-like activity has never been investigated. Through the comparison of the DPP-4 activity in the cecal content of germ-free mice (GFM) and gnotobiotic mice colonized with the gut microbiota of a healthy subject, we bring the proof of concept that a significant DPP-4-like activity occurs in the microbiota. By analyzing the existing literature, we propose that DPP-4-like activity encoded by the intestinal microbiome could constitute a novel mechanism to modulate protein digestion as well as host metabolism and behavior.This work was supported by EU grant 613979 (MyNewGut). MO is a beneficiary of a “MOVE-IN Louvain” Incoming Post-doctoral Fellowship co-funded by UCLouvain and the Marie Curie Actions of the European Commission.Peer Reviewe

Inulin-type fructans modulate intestinal Bifidobacterium species populations and decrease fecal short-chain fatty acids in obese women

Background & aims : Inulin-type fructans (ITF) prebiotics promote changes in the composition and activity of the gut microbiota. The aim of this study was to determine variations on fecal short chain fatty acids (SCFA) concentration in obese women treated with ITF and to explore associations between Bifidobacterium species, SCFA and host biological markers of metabolism. Methods Samples were obtained in a randomized, double blind, parallel, placebo-controlled trial, with 30 obese women randomly assigned to groups that received either 16 g/day ITF (n = 15) or maltodextrin (n = 15) for 3 months. The qualitative and quantitative analysis of Bifidobacterium spp. was performed in feces by PCR-DGGE and q-PCR, and SCFA profile was analyzed by gas chromatography. Spearman correlation analysis was performed between the different variables analyzed. Results The species Bifidobacterium longum, Bifidobacterium pseudocatenulatum and Bifidobacterium adolescentis were significantly increased at the end of the treatment in the prebiotic group (p <0.01) with being B. longum negatively correlated with serum lipopolysaccharide (LPS) endotoxin (p <0.01). Total SCFA, acetate and propionate, that positively correlated with BMI, fasting insulinemia and homeostasis model assessment (HOMA) (p <0.05), were significantly lower in prebiotic than in placebo group after the treatment period. Conclusions ITF consumption selectively modulates Bifidobacterium spp. and decreases fecal SCFA concentration in obese women. ITF could lessen metabolic risk factors associated with higher fecal SCFA concentration in obese individuals

土壤吸附揮發性有機物的實驗研究方法

The aim of EU project MyNewGut is to contribute to future public health-related recommendations supported by new insight in gut microbiome and nutrition-host relationship. In this Opinion Paper, we first revisit the concept of dietary fiber, taking into account their interaction with the gut microbiota. This paper also summarizes the main effects of dietary fibers with prebiotic properties in intervention studies in humans, with a particular emphasis on the effects of arabinoxylans and arabinoxylo-oligosaccharides on metabolic alterations associated with obesity. Based on the existing state of the art and future development, we elaborate the steps required to propose dietary guidelines related to dietary fibers, taking into account their interaction with the gut microbiota.The MyNewGut project is financially supported by a grant from the EU 7th Framework Program under Grant Agreement 613979. MO is a beneficiary of a “MOVE-IN Louvain” grant (incoming Post-Doctoral Fellowship co-funded by the Marie Curie Actions of the European Commission)

P180: Intérêt de la modulation du microbiote intestinal par les oligosaccharides non digestibles dans le contrôle de la leucémie et de la cachexie cancéreuse

Il est à présent clairement établi que l’ensemble des bactéries présentes dans l’intestin (le microbiote intestinal) est capable d’influencer l’homéostasie énergétique et immunitaire de son hôte. Nous avons testé l’hypothèse selon laquelle une modulation du microbiote intestinal par des oligosaccharides issus de la pectine (POS) ou de l’inuline (INU) permet d’interférer avec la progression de la leucémie et des désordres métaboliques associés

GUT MICROBIOTA IS IMPLICATED IN CANCER-INDUCED CACHEXIA

BACKGROUND AND AIMS : We know that the gut microbiota is implicated in energy metabolism and it role has been mostly studied upon obesity . Here we set the hypothesis that the gut microbiota could also be implicated in metabolic alterations associated with cancer, cachexia. METHODS : This hypothesis was assessed in BALB/c mice intravenously injected with mouse proB BAF3 cells transfected with BCR-ABL gene in order to allow the development of chronic myelogenous leukemia (CML). Muscles (tibialis, gastrocnemius), liver, intestine and adipose tissues were withdrawn 2 weeks after injection for further biochemical and histological analysis. Gut microbiota composition was assessed by RT-qPCR. RESULTS : BCR-ABL expressing CML constitutes a new model of cancer cachexia, as proven by a decrease in adipose and muscle tissue weights. In both male and female, Lactobacillus spp. levels in caecal content drastically decrease, independently of food intake (p<0,001). Moreover, this decrease is highly correlated to muscle markers of atrophy, such as Atrogin-1 mRNA (r = -0,8885, p<0,0001). Finally, increasing the level of Lactobacillus spp. levels by dietary prebiotics allows to lessen Atrogin-1 mRNA induction in the muscle. CONCLUSIONS : In this new model of cancer cachexia, we highlight two important facts : first, gut microbiota modification is associated with cancer-induced cachexia ; second, modulation of gut microbiota counteracts markers of muscle atrophy. Therefore, we suggest that gut microbiota is implicated in cancer cachexia and may constitute a new target in the treatment of this metabolic disease