Extracellular Vesicles Derived from Gut Microbiota,Especially Akkermansia muciniphila,Protect the Progression of Dextran Sulfate Sodium-Induced Colitis

Gut microbiota play an important part in the pathogenesis of mucosal inflammation, such as inflammatory bowel disease (IBD). However, owing to the complexity of the gut microbiota, our understanding of the roles of commensal and pathogenic bacteria in the maintenance of immune homeostasis in the gut is evolving only slowly. Here, we evaluated the role of gut microbiota and their secreting extracellular vesicles (EV) in the development of mucosal inflammation in the gut. Experimental IBD model was established by oral application of dextran sulfate sodium (DSS) to C57BL/6 mice. The composition of gut microbiota and bacteria-derived EV in stools was evaluated by metagenome sequencing using bacterial common primer of 16S rDNA. Metagenomics in the IBD mouse model showed that the change in stool EV composition was more drastic, compared to the change of bacterial composition. Oral DSS application decreased the composition of EV from Akkermansia muciniphila and Bacteroides acidifaciens in stools, whereas increased EV from TM7 phylum, especially from species DQ777900_s and AJ400239_s. In vitro pretreatment of A. muciniphila-derived EV ameliorated the production of a pro-inflammatory cytokine IL-6 from colon epithelial cells induced by Escherichia coli EV. Additionally, oral application of A. muciniphila EV also protected DSS-induced IBD phenotypes, such as body weight loss, colon length, and inflammatory cell infiltration of colon wall. Our data provides insight into the role of gut microbiota-derived EV in regulation of intestinal immunity and homeostasis, and A. muciniphila-derived EV have protective effects in the development of DSS-induced colitis.     

<Emphasis Type="Italic">Lactobacillus curvatus</Emphasis> WiKim38 isolated from kimchi induces IL-10 production in dendritic cells and alleviates DSS-induced colitis in mice

Probiotics such as lactobacilli and bifidobacteria have healthpromoting effects by immune modulation. In the present study, we examined the immunomodulatory properties of Lactobacillus curvatus WiKim38, which was newly isolated from baechu (Chinese cabbage) kimchi. The ability of L. curvatus WiKim38 to induce cytokine production in bone marrow-derived dendritic cells (BMDCs) was determined by enzyme-linked immunosorbent assay. To evaluate the molecular mechanisms underlying L. curvatus Wikim38-mediated IL-10 production, Western blot analyses and inhibitor assays were performed. Moreover, the in vivo anti-inflammatory effects of L. curvatus WiKim38 were examined in a dextran sodium sulfate (DSS)-induced colitis mouse model. L. curvatus WiKim38 induced significantly higher levels of IL-10 in BMDCs compared with that induced by LPS. NF-κB and ERK were activated by L. curvatus WiKim38, and an inhibitor assay revealed that these pathways were required for L. curvatus WiKim38-induced production of IL-10 in BMDCs. An in vivo experiment showed that oral administration of L. curvatus WiKim38 increased the survival rate of mice with DSS-induced colitis and improved clinical signs and histopathological severity in colon tissues. Taken together, these results indicate that L. curvatus Wikim38 may have health-promoting effects via immune modulation, and may thus be applicable for therapy of various inflammatory diseases.     

A murine colitis model developed using a combination of dextran sulfate sodium and <Emphasis Type="Italic">Citrobacter rodentium</Emphasis>

Adult mice were treated with dextran sulfate sodium (DSS) and infected with Citrobacter rodentium for developing a novel murine colitis model. C57BL/6N mice (7-week-old) were divided into four groups. Each group composed of control, dextran sodium sulfate-treated (DSS), C. rodentium-infected (CT), and DSS-treated and C. rodentium-infected (DSS-CT) mice. The DSS group was administered 1% DSS in drinking water for 7 days. The CT group was supplied with normal drinking water for 7 days and subsequently infected with C. rodentium via oral gavage. The DSS-CT group was supplied with 1% DSS in drinking water for 7 days and subsequently infected with C. rodentium via oral gavage. The mice were sacrificed 10 days after the induction of C. rodentium infection. The DSS-CT group displayed significantly shorter colon length, higher spleen to body weight ratio, and higher histopathological score compared to the other three groups. The mRNA expression levels of tumor necrosis factor (TNF)-α and interferon (INF)-γ were significantly upregulated; however, those of interleukin (IL)-6 and IL-10 were significantly downregulated in the DSS-CT group than in the control group. These results demonstrated that a combination of low DSS concentration (1%) and C. rodentium infection could effectively induce inflammatory bowel disease (IBD) in mice. This may potentially be used as a novel IBD model, in which colitis is induced in mice by the combination of a chemical and a pathogen.     

A model for dextran sodium sulfate (DSS)-induced mouse colitis: bacterial degradation of DSS does not occur after incubation with mouse cecal contents.

Germ-free (GF) mice are highly susceptible to dextran sodium sulfate (DSS)-induced colitis in comparison to conventionalized (CVz) mice. It is hypothesized that degradation of DSS by intestinal microflora is involved in the susceptibility to DSS-induced colitis of GF mice. This study evaluates the ability of bacteria in mouse cecal contents (CC) to degrade DSS in vitro, and provides confirmatory evidence that DSS was not degraded when incubated with CC. Our results suggest that intestinal microflora do not contribute directly to the difference in susceptibility of GF mice to DSS-induced colitis through degradation.     

A lactic acid bacterium isolated from kimchi ameliorates intestinal inflammation in DSS-induced colitis

Some species of lactic acid bacteria have been shown to be beneficial in inflammatory bowel disease (IBD). In the present study, a strain of lactic acid bacterium (Lactobacillus paracasei LS2) was isolated from the Korean food, kimchi, and was shown to inhibit the development of experimental colitis induced by dextran sulfate sodium (DSS). To investigate the role of LS2 in IBD, mice were fed DSS in drinking water for seven days along with LS2 bacteria which were administered intragastrically to some of the mice, while phosphate-buffered saline (PBS) was administered to others (the controls). The administration of LS2 reduced body weight loss and increased survival, and disease activity indexes (DAI) and histological scores indicated that the severity of colitis was significantly reduced. The production of inflammatory cytokines and myeloperoxidase (MPO) activity also decreased. Flow cytometry analysis showed that the number of Th1 (IFN-γ) population cells was significantly reduced in the LS2-administered mice compared with the controls. The administration of LS2 induced the increase of CD4⁺FOXP3⁺ Treg cells, which are responsible for IL-10. Numbers of macrophages (CD11b⁺ F4/80⁺), and neutrophils (CD11b⁺ Gr-1⁺) among lamina propria lymphocytes (LPL) were also reduced. These results indicate that LS2 has an anti-inflammatory effect and ameliorates DSS-induced colitis.     

Probiotic bacteria produce conjugated linoleic acid locally in the gut that targets macrophage PPAR γ to suppress colitis

Background

Inflammatory bowel disease (IBD) therapies are modestly successful and associated with significant side effects. Thus, the investigation of novel approaches to prevent colitis is important. Probiotic bacteria can produce immunoregulatory metabolites in vitro such as conjugated linoleic acid (CLA), a polyunsaturated fatty acid with potent anti-inflammatory effects. This study aimed to investigate the cellular and molecular mechanisms underlying the anti-inflammatory efficacy of probiotic bacteria using a mouse model of colitis.

Methodology/Principal Findings

The immune modulatory mechanisms of VSL#3 probiotic bacteria and CLA were investigated in a mouse model of DSS colitis. Colonic specimens were collected for histopathology, gene expression and flow cytometry analyses. Immune cell subsets in the mesenteric lymph nodes (MLN), spleen, blood and colonic lamina propria cells were phenotypically and functionally characterized. Fecal samples and colonic contents were collected to determine the effect of VSL#3 and CLA on gut microbial diversity and CLA production. CLA and VSL#3 treatment ameliorated colitis and decreased colonic bacterial diversity, a finding that correlated with decreased gut pathology. Colonic CLA concentrations were increased in response to probiotic bacterial treatment, but without systemic distribution in blood. VSL#3 and CLA decreased macrophage accumulation in the MLN of mice with DSS colitis. The loss of PPAR γ in myeloid cells abrogated the protective effect of probiotic bacteria and CLA in mice with DSS colitis.

Conclusions/Significance

Probiotic bacteria modulate gut microbial diversity and favor local production of CLA in the colon that targets myeloid cell PPAR γ to suppress colitis.     

Comparative analysis of the gut microbiota in distinct statin response patients in East China

Statin response shows great interindividual variations. Recently, emerging studies have shown that gut microbiota is linked to therapeutic responses to drugs, including statins. However, the association between the gut bacteria composition and statin response is still unclear. In this study, gut microbiota of 202 hyperlipidemic patients with statin sensitive (SS) response and statin resistant (SR) response in East China were investigated by high throughput sequencing to compare the gut bacteria composition and biodiversity in distinct statin response patients. Higher biodiversity was detected in Group SS than Group SR. Specifically, group SS showed significantly increased proportion of genera Lactobacillus (P = 0.001), Eubacterium (P = 0.004), Faecalibacterium (P = 0.005), and Bifidobacterium (P = 0.002) and decreased proportion of genus Clostridium (P = 0.001) compared to Group SR. The results indicated that higher gut biodiversity was associated with statin sensitive response. The increased genera Lactobacillus, Eubacterium, Faecalibacterium, Bifidobacterium, and decreased genus Clostridium in patient gut microbiota may predict patient's statin response, and hence may guide statin dosage adjustments.     

Colonization by non-pathogenic bacteria alters mRNA expression of cytochromes P450 in originally germ-free mice

Gut microbiota provides a wide range of beneficial function for the host and has an immense effect on the host’s health state. It has also been shown that gut microbiome is often involved in the biotransformation of xenobiotics; however, the molecular mechanisms of the interaction between the gut bacteria and the metabolism of drugs by the host are still unclear. To investigate the effect of microbial colonization on messenger RNA (mRNA) expression of liver cytochromes P450 (CYPs), the main drug-metabolizing enzymes, we used germ-free (GF) mice, lacking the intestinal flora and mice monocolonized by non-pathogenic bacteria Lactobacillus plantarum ^NIZO2877 or probiotic bacteria Escherichia coli Nissle 1917 compared to specific pathogen-free (SPF) mice. Our results show that the mRNA expression of Cyp1a2 and Cyp2e1 was significantly increased, while the expression of Cyp3a11 mRNA was decreased under GF conditions compared to the SPF mice. The both bacteria L. plantarum ^NIZO2877 and E. coli Nissle 1917 given to the GF mice decreased the level of Cyp1a2 mRNA and normalized it to the control level. On the other hand, the colonization by these bacteria had no effect on the expression of Cyp3a11 mRNA in the liver of the GF mice (which remained decreased). Surprisingly, monocolonization with chosen bacterial strains has shown a different effect on the expression of Cyp2e1 mRNA in GF mice. Increased level of Cyp2e1 expression observed in the GF mice was found also in mice colonized by L. plantarum ^NIZO2877; however, the colonization with probiotic E. coli Nissle 1917 caused a decrease in Cyp2e1 expression and partially restored the SPF mice conditions.     

Effects of neutrophils peptide-1 transgenic <Emphasis Type="Italic">Chlorella ellipsoidea</Emphasis> on the gut microbiota of male Sprague–Dawley rats,as revealed by high-throughput 16S rRNA sequencing

Rabbit neutrophils peptide-1 (NP-1) is a type of defensin that possesses a broad spectrum of antimicrobial activity. Chlorella ellipsoidea is a new eukaryotic expression system for exogenously producing NP-1. The NP-1 transgenic C. ellipsoidea can be directly added into feed as antimicrobial agent without any purification procedure for the NP-1 peptide. However, the effects of C. ellipsoidea and NP-1 on the host gut microbiota should be explored before application. In this study, diets containing different concentrations (1.25, 2.5, and 5 %) of C. ellipsoidea and NP-1 transgenic C. ellipsoidea were administered to male Sprague–Dawley rats. Compared with the chow diet control group, none of the experimental groups showed any significant differences in their growth indices, and no histopathological damage was observed. The phylotypes of gut microbiota in the control group, the 5 % C. ellipsoidea diet group and the 5 % NP-1 transgenic C. ellipsoidea diet group were determined by 16S rRNA sequencing. The results showed that both 5 % experimental groups had shifted community memberships of gut microbiota. In particular, the 5 % NP-1 transgenic C. ellipsoidea diet exhibited an increased abundance of most Gram-positive bacterial taxa and a reduced abundance of most Gram-negative bacterial taxa, and it promoted the growth of some lactic acid bacterial genera. Lactic acid bacteria, especially the Bifidobacterium and Lactobacillus, have been widely reported to be benefic effects on the host. Thus NP-1 transgenic C. ellipsoidea is promising feed additive and gut regulator, as it have the potential to increase the abundance of Bifidobacterium and Lactobacillus in gut microbiota of animal.     

Bioinformatics Analysis of Antimicrobial Resistance Genes and Prophages Colocalized in Human Gut Metagenomes

The constant increase of bacterial antibiotic-resistant strains is directly linked to a common use of antibiotics in medicine and animal breeding. It is suggested that the gut microbiota serves as a reservoir for antibiotic resistance genes that can be transferred from symbiotic bacteria to pathogenic ones, particularly due to phage transduction. In this study, using the PHASTER prophage predicting tool and CARD antibiotics resistance database we have searched for antibiotic resistance genes that are located within prophages in human gut microbiota. After analysing metagenomic assemblies of eight samples of antibiotic treated patients, lsaE, mdfA, and cpxR/cpxA genes were identified inside prophages. These genes confer resistance to antimicrobial peptides, pleuromutilin, lincomycins, streptogramins and also multidrug resistance. Three (0.46%) of 659 putative prophages predicted in the metagenomic assemblies contained antibiotics resistance genes in their sequences.     

A standardized approach for co-culturing dothidealean rock-inhabiting fungi and lichen photobionts in vitro

Owing to the effect of symbiotic gut bacteria on the proliferation of infectious disease-transferring insects and their potential as paratransgenic tools, their identification or securing their use in controlling insect vectors is urgently needed. Bradysia agrestis is one of the major plant epidemic vectors in East Asia; however, its normal microbiota remains unstudied. This research was primarily designed to secure promising candidates for use in a paratransgenic approach to phytopathogen control, as well as to provide a picture of the gut microbiota of wild-caught B. agrestis from a blight field. A total of 180 larvae from three different regions in South Korea were analyzed for their gut microfloral composition. Diverse bacterial strains were purely isolated based on morphological differences in microbiological media. We found a total of 64 bacterial strains in the B. agrestis midgut and analyzed their 16S rRNA gene sequences for molecular identification and phylogenetic characterization. Furthermore, the microbial diversity of each normal microbiota group was analyzed with various diversity indices. Bacterial biota including species diversity, richness or species distribution, species constituents, and dominance varied by each regional vector group. The most widely distributed species was Bacillus aryabhattai, and the most common genera were Bacillus and Microbacterium. These saprophytic bacteria were isolated from all regional groups and their potential as paratransgenic candidates for controlling B. agrestis-mediated plant disease is discussed.     

Fecal Bacterial Composition of Sichuan Snub-Nosed Monkeys (<Emphasis Type="Italic">Rhinopithecus roxellana</Emphasis>)

The intestinal microbiota plays an important role in maintaining the health of its host, including human and nonhuman primates. Little is known about the intestinal bacterial composition of the Sichuan snub-nosed monkey (Rhinopithecus roxellana), which has been classified as Endangered on the International Union for Conservation of Nature Red List since 2003. We evaluated the fecal bacterial compositions of 11 Sichuan snub-nosed monkeys, including six young captive individuals (one sample from each), three adult captive individuals (four samples each), and two adult provisioned free-ranging individuals (four samples each). We also quantified fecal Bacteroides vulgatus, Bifidobacterium spp., and Lactobacillus spp., which are defined as probiotics in humans, using real-time polymerase chain reaction. We identified five major phyla in the collected samples, including Firmicutes (32.4 %), Bacteroidetes (14.7 %), Verrucomicrobia (8.8 %), Actinobacteria (4.4 %), and unclassified microbacteria (39.7 %). Fecal bacteria composition varied with age and different seasons. The fecal bacterial composition of the captive monkeys was less variable than that of provisioned free-ranging monkeys. B. vulgatus amounts were almost 100 times higher in the provisioned free-ranging monkeys (10¹²) than in the captive monkeys (10¹⁰). Our results provide an initial catalogue of gut microbiota in the Sichuan snub-nosed monkey, which helps to enrich our knowledge of gut microbiota in nonhuman primates.     

Comparative Effect of the I3.1 Probiotic Formula in Two Animal Models of Colitis

Use of probiotic therapy is an active area of investigation to treat intestinal disorders. The clinical benefits of the I3.1 probiotic formula (Lactobacillus plantarum (CECT7484, CECT7485) and P. acidilactici (CECT7483)) were demonstrated in irritable bowel syndrome (IBS) patients in a randomized, double-blind, placebo-controlled clinical trial. The aim of this study was to evaluate the therapeutic effects of I3.1 in two experimental models of colitis, a dextran sulfate sodium (DSS)-induced colitis model and an interleukin (IL)-10-deficient mice model. Colitis was induced in 32 8-week-old Balb/c mice by administering 3% (w/v) DSS in drinking water for 5 days. Probiotics were administered orally (I3.1 or VSL#3, 1 × 10⁹ CFU daily) for 10 days before the administration of DSS. Also, probiotics (I3.1 or VSL#3, 1 × 10⁹ CFU daily) were administered orally to 36 6-week-old C57B6J IL-10(?/?) mice for 10 weeks. Body weight was recorded daily. Colon samples were harvested for histological examination and cytokine measurements. Body weight after DSS administration did not change in the I3.1 group, whereas the VSL#3 group had weight loss. Also, I3.1 normalized IL-6 to levels similar to that of healthy controls and significantly increased the reparative histologic score. In the IL-10-deficient model, both VSL#3 and I3.1 reduced the severity of colitis compared to untreated controls, and I3.1 significantly reduced the levels of IFN-γ compared to the other two groups. In conclusion, I3.1 displays a protective effect on two murine models of experimental colitis. Results suggest that the mechanism of action could be different from VSL#3.     

Intestinal anti-inflammatory effect of the probiotic Saccharomyces boulardii in DSS-induced colitis in mice: Impact on microRNAs expression and gut microbiota composition

The beneficial effects exerted by probiotics in inflammatory bowel disease (IBD) are well known, although their exact mechanisms have not been fully elucidated, and only few studies have focused on their impact on selected miRNAs and the gut microbiota composition. Therefore, our aim was to correlate the intestinal anti-inflammatory activity of the probiotic Saccharomyces boulardii in the dextran sodium sulphate (DSS) model of mouse colitis and the changes induced in miRNA expression and gut microbiota populations. Probiotic was given orally (5×10⁹ CFU) to C57BL/6 mice for 26 days. After 2 weeks, the colitis was induced adding DSS to the drinking water. Mice were scored daily using a Disease Activity Index (DAI). After sacrifice, the colonic specimens were evaluated by determining the expression of inflammatory markers and micro-RNAs by qRT-PCR. Moreover, changes in microbiota populations were evaluated by pyrosequencing. Probiotic ameliorated the colonic damage induced by DSS, as evidenced by lower DAI values and colonic weight/length compared with untreated mice. The treatment modified the colonic expression of different inflammatory markers and the epithelial integrity proteins, and induced changes in micro-RNAs expression. Moreover, microbiota characterization showed that probiotic treatment increased bacterial diversity, thus ameliorating the dysbiosis produced by DSS-colitis. Saccharomyces boulardii exerted intestinal anti-inflammatory effects in DSS-mouse colitis, through the modulation in the immune response, involving modification of altered miRNA expression, being associated to the improvement of the inflammation-associated dysbiosis in the intestinal lumen, which could be of great interest to control the complex pathogenesis of IBD.     

Microbiota dysbiosis in inflammatory bowel diseases: <Emphasis Type="Italic">in silico</Emphasis> investigation of the oxygen hypothesis

Background

Inflammatory bowel diseases (IBD), which include ulcerative colitis and Crohn’s disease, cause chronic inflammation of the digestive tract in approximately 1.6 million Americans. A signature of IBD is dysbiosis of the gut microbiota marked by a significant reduction of obligate anaerobes and a sharp increase in facultative anaerobes. Numerous experimental studies have shown that IBD is strongly correlated with a decrease of Faecalibacterium prausnitzii and an increase of Escherichia coli. One hypothesis is that chronic inflammation induces increased oxygen levels in the gut, which in turn causes an imbalance between obligate and facultative anaerobes.

Results

To computationally investigate the oxygen hypothesis, we developed a multispecies biofilm model based on genome-scale metabolic reconstructions of F. prausnitzii, E. coli and the common gut anaerobe Bacteroides thetaiotaomicron. Application of low bulk oxygen concentrations at the biofilm boundary reproduced experimentally observed behavior characterized by a sharp decrease of F. prausnitzii and a large increase of E. coli, demonstrating that dysbiosis consistent with IBD disease progression could be qualitatively predicted solely based on metabolic differences between the species. A diet with balanced carbohydrate and protein content was predicted to represent a metabolic “sweet spot” that increased the oxygen range over which F. prausnitzii could remain competitive and IBD could be sublimated. Host-microbiota feedback incorporated via a simple linear feedback between the average F. prausnitzii concentration and the bulk oxygen concentration did not substantially change the range of oxygen concentrations where dysbiosis was predicted, but the transition from normal species abundances to severe dysbiosis was much more dramatic and occurred over a much longer timescale. Similar predictions were obtained with sustained antibiotic treatment replacing a sustained oxygen perturbation, demonstrating how IBD might progress over several years with few noticeable effects and then suddenly produce severe disease symptoms.

Conclusions

The multispecies biofilm metabolic model predicted that oxygen concentrations of ～1 micromolar within the gut could cause microbiota dysbiosis consistent with those observed experimentally for inflammatory bowel diseases. Our model predictions could be tested directly through the development of an appropriate in vitro system of the three species community and testing of microbiota-host interactions in gnotobiotic mice.

     

Ethnicity influences gut metabolites and microbiota of the tribes of Assam,India

Introduction

The human gut microbes and their metabolites are involved in multiple host metabolic pathways. Dysbiosis in the gut microbiota and altered metabolite profiles were reported in diseased state. In a region like Assam, where 12.4% of the populations are tribal population, evaluating the influence of ethnicity on gut microbiota and metabolites has become important to further differentiate it from the diseased state.

Objective

To study the influence of ethnicity on fecal metabolite profile and their association with the gut microbiota composition.

Methods

In this study, we determined the untargeted fecal metabolites from five ethnic groups of Assam (Tai-Aiton, Bodo, Karbi, Tea-tribe and Tai-Phake) using GC–MS and compared them among the tribes for common and unique metabolites. Metabolites of microbial origin were related with the available metagenomic data on gut bacterial profiles of the same ethnic groups and functional analysis were carried out based on HMDB.

Results

The core fecal metabolite profile of the Tea-tribe contained aniline, benzoate and acetaldehyde. PLS-DA based on the metabolites suggested that the individuals grouped based on their ethnicity. PCA plot of the data on bacterial abundance at the level of genus indicated clustering of individuals based on ethnicity. Positive correlations were observed between propionic acid and the genus Clostridium (R?=?0.43 and p?=?0.03), butyric acid and the genus Lactobacillus (R?=?0.45 and p?=?0.024), acetic acid and the genus Bacteroides (R?=?0.63 and p?=?0.001) and methane and the genus Escherichia (R?=?0.58 and p?=?0.002).

Conclusion

Results of this study indicated that ethnicity influences both gut bacterial profile and their metabolites.

     

Metagenomic analysis of taxonomic and functional changes in gut microbiota of patients with the alcohol dependence syndrome

The first metagenomic study of gut microbiota in patients with the alcohol dependence syndrome (ADS) has been performed in the whole-genome sequencing (“shotgun”) format. Taxonomic analysis revealed changes in the relative abundance of the predominant bacteria associated with inflammatioln (including increased levels of Ruminococcus gnavus and R. torques, and decreased levels of Faecalibacterium and Akkermansia genera). The microbiota of ADS patients was characterized by the presence of opportunistic pathogens rarely detected in metagenomes of healthy individuals from different countries. Comparative analysis of total metabolic potential revealed increased relative abundance of KEGG pathways associated with the response to oxidative stress. ADS patients also had increased levels of two specific groups of genes encoding enzymes involved in the metabolism of alcohol, as well as virulence factors. It is possible that gut microbiota of ADS patients demonstrating changes in both taxonomic and functional composition plays a role in modulating the effects of alcohol on the host body     

Influence of food consumption patterns and Galician lifestyle on human gut microbiota

The proportion of different microbial populations in the human gut is an important factor that in recent years has been linked to obesity and numerous metabolic diseases. Because there are many factors that can affect the composition of human gut microbiota, it is of interest to have information about what is the composition of the gut microbiota in different populations in order to better understand the possibilities for improving nutritional management. A group of 31 volunteers were selected according to established inclusion and exclusion criteria and were asked about their diet history, lifestyle patterns, and adherence to the Southern European Atlantic Diet. Fecal samples were taken and subsequently analyzed by real-time PCR. The results indicated different dietary patterns for subjects who consumed a higher amount of fruits, vegetables, legumes, and fish and a lower amount of bakery foods and precooked foods and snacks compared to Spanish consumption data. Most participants showed intermediate or high adherence to Southern European Atlantic Diet, and an analysis of gut microbiota showed high numbers of total bacteria and Actinobacteria, as well as high amounts of bacteria belonging to the genera Lactobacillus spp. and Bifidobacterium spp. A subsequent statistical comparison also revealed differences in gut microbiota depending on the subject’s body weight, age, or degree of adherence to the Southern European Atlantic Diet.     

Milk fat globule-EGF factor 8 is a critical protein for healing of dextran sodium sulfate-induced acute colitis in mice

Milk fat globule-EGF factor 8 (MFG-E8) has been shown to play an important role in maintaining the integrity of the intestinal mucosa and to accelerate healing of the mucosa in septic mice. Herein, we (a) analyzed the expression of MFG-E8 in the gut of wild-type (WT) C57BL/6 (MFG-E8(+/+)) mice with and without dextran sulfate sodium (DSS)-induced colitis, (b) characterized the pathological changes in intestinal mucosa of MFG-E8(+/+) and MFG-E8(-/-) mice with DSS-induced colitis and (c) examined the therapeutic role of MFG-E8 in inflammatory bowel disease by using DSS-induced colitis model. Our data documented that there was an increase in colonic and rectal MFG-E8 expression in MFG-E8(+/+) mice during the development of DSS colitis. MFG-E8 levels in both tissues decreased to below baseline during the recovery phase in mice with colitis. Changes in MFG-E8 gene expression correlated to the levels of inflammatory response and crypt-epithelial injury in both colonic and rectal mucosa in MFG-E8(+/+) mice. MFG-E8(-/-)mice developed more severe crypt-epithelial injury than MFG-E8(+/+) mice during exposure to DSS with delayed healing of intestinal epithelium during the recovery phase of DSS colitis. Administration of MFG-E8 during the recovery phase ameliorated colitis and promoted mucosal repair in both MFG-E8(-/-) and MFG-E8(+/+) mice, indicating that lack of MFG-E8 causes increased susceptibility to colitis and delayed mucosal healing. These data suggest that MGF-E8 is an essential protective factor for gut epithelial homeostasis, and exogenous administration of MFG-E8 may represent a novel therapeutic target in inflammatory bowel disease.     

Dominant Effects of the Diet on the Microbiome and the Local and Systemic Immune Response in Mice

Outside the nutrition community the effects of diet on immune-mediated diseases and experimental outcomes have not been appreciated. Investigators that study immune-mediated diseases and/or the microbiome have overlooked the potential of diet to impact disease phenotype. We aimed to determine the effects of diet on the bacterial microbiota and immune-mediated diseases. Three different laboratory diets were fed to wild-type mice for 2 weeks and resulted in three distinct susceptibilities to dextran sodium sulfate (DSS)-induced colitis. Examination of the fecal microbiota demonstrated a diet-mediated effect on the bacteria found there. Broad-spectrum antibiotics disturbed the gut microbiome and partially eliminated the diet-mediated changes in DSS susceptibility. Dietary changes 2 days after DSS treatment were protective and suggested that the diet-mediated effect occurred quickly. There were no diet-mediated effects on DSS susceptibility in germ-free mice. In addition, the diet-mediated effects were evident in a gastrointestinal infection model (Citrobacter rodentium) and in experimental autoimmune encephalomyelitis. Taken together, our study demonstrates a dominant effect of diet on immune-mediated diseases that act rapidly by changing the microbiota. These findings highlight the potential of using dietary manipulation to control the microbiome and prevent/treat immune-mediated disease.