Microbial Population Differentials between Mucosal and Submucosal Intestinal Tissues in Advanced Crohn's Disease of the Ileum

Distinct anal microbiome is correlated with anal cancer precursors in MSM with HIV

OBJECTIVES

Anal cancer risk is elevated in MSM with HIV (MSMWH). Anal high-risk human papillomavirus (hr-HPV) infection is necessary but insufficient to develop high-grade squamous intraepithelial lesion (HSIL), the anal cancer precursor, suggesting additional factors. We sought to determine whether the microbiome of the anal canal is distinct by comparing it with the microbiome of stool. We also sought to determine whether changes in the anal microbiome are associated with HSIL among MSMWH.

DESIGN

Cross-sectional comparison of the microbiome of the anal canal with the microbiome of stool in MSMWH and cross-sectional comparison of the anal microbiome of MSMWH with anal HSIL with the anal microbiome of MSMWH without anal HSIL.

METHODS

Sterile swabs were used to sample the anus of MSMWH for microbiome and HPV testing, followed by high-resolution anoscopy. Stool samples were mailed from home. 16S sequencing was used for bacterial identification. Measures of alpha diversity, beta diversity, and differential abundance analysis were used to compare samples.

RESULTS

One hundred sixty-six anal samples and 103 matching stool samples were sequenced. Beta diversity showed clustering of stool and anal samples. Of hr-HPV-positive MSMWH, 31 had HSIL and 13 had no SIL. Comparison of the microbiome between these revealed 28 different species. The highest-fold enrichment among MSMWH/hr-HPV/HSIL included pro-inflammatory and carcinogenic Prevotella, Parasuterella, Hungatella, Sneathia, and Fusobacterium species. The anti-inflammatory Anaerostipes caccae showed the greatest reduction among MSMWH/hr-HPV/HSIL.

CONCLUSION

The anal microbiome is distinct from stool. A pro-inflammatory and carcinogenic environment may be associated with anal HSIL.

Association between gut microbiota and adrenal disease: a two-sample Mendelian randomized study

Background

Some observational studies and clinical experiments suggest a close association between gut microbiota and metabolic diseases. However, the causal effects of gut microbiota on adrenal diseases, including Adrenocortical insufficiency, Cushing syndrome, and Hyperaldosteronism, remain unclear.

Methods

This study conducted a two-sample Mendelian randomization analysis using summary statistics data of gut microbiota from a large-scale genome-wide association study conducted by the MiBioGen Consortium. Summary statistics data for the three adrenal diseases were obtained from the FinnGen study. The study employed Inverse variance weighting, MR-Egger, and MR-PRESSO methods to assess the causal relationship between gut microbiota and these three adrenal diseases. Additionally, a reverse Mendelian randomization analysis was performed for bacteria found to have a causal relationship with these three adrenal diseases in the forward Mendelian randomization analysis. Cochran's Q statistic was used to test for heterogeneity of instrumental variables.

Results

The IVW test results demonstrate that class Deltaproteobacteria, Family Desulfovibrionaceae, and Order Desulfovibrionales exhibit protective effects against adrenocortical insufficiency. Conversely, Family Porphyromonadaceae, Genus Lachnoclostridium, and Order MollicutesRF9 are associated with an increased risk of adrenocortical insufficiency. Additionally, Family Acidaminococcaceae confers a certain level of protection against Cushing syndrome. In contrast, Class Methanobacteria, Family Lactobacillaceae, Family Methanobacteriaceae, Genus. Lactobacillus and Order Methanobacteriales are protective against Hyperaldosteronism. Conversely, Genus Parasutterella, Genus Peptococcus, and Genus Veillonella are identified as risk factors for Hyperaldosteronism.

Conclusions

This two-sample Mendelian randomization analysis revealed a causal relationship between microbial taxa such as Deltaproteobacteria and Desulfovibrionaceae and Adrenocortical insufficiency, Cushing syndrome, and Hyperaldosteronism. These findings offer new avenues for comprehending the development of adrenal diseases mediated by gut microbiota.

Coumarin Glycosides Reverse Enterococci-Facilitated Enteric Infections

Commensal enterococci with pathogenic potential often facilitate the growth of diverse pathogens, thereby exacerbating infections. However, there are few effective therapeutic strategies to prevent and intervene in enterococci-mediated polymicrobial infections. Here, we find that enterococci at high density drive the expansion and pathogenicity of enteric Salmonella enterica serotype Typhimurium (S. Tm). Subsequently, we show that the driving role of enterococci in such infections is counteracted by dietary coumarin glycosides in vivo. Enterococci, which are tolerant of iron-deficient environments, produce β-glucosidases to hydrolyze coumarin glycosides into bioactive aglycones, inhibiting S. Tm growth and ameliorating the severity of S. Tm-induced symptoms by inducing iron limitation. Overall, we demonstrate that coumarin glycosides as a common diet effectively reverse enterococci-facilitated enteric infections, providing an alternative intervention to combat polymicrobial infections.

The gut-brain-axis: A positive relationship between gut microbial dysbiosis and glioblastoma brain tumour

The glioblastoma brain tumour (GBM) stands out as the most aggressive and resistant-to-treatment malignancy. Nevertheless, the gut-brain connection plays a pivotal role in influencing the growth and activation of the central nervous system. In this particular investigation, we aimed to assess and characterize the gut microbial ecosystem in GBM patients, both quantitatively and qualitatively. We collected faecal samples from 15 healthy volunteers and 25 GBM patients. To delve into the microbial content, we employed PCR-DGGE, targeting the V3 region of the 16S rRNA gene, and conducted qPCR to measure the levels of crucial intestinal bacteria. For a more in-depth analysis, high-throughput sequencing was performed on a selection of 20 random faecal samples (10 from healthy individuals and 10 from GBM patients), targeting the V3+V4 region of the 16S rRNA gene. Our findings from examining the richness and diversity of the gut microbiota unveiled that GBM patients exhibited significantly higher microbial diversity compared to healthy individuals. At the phylum level, Proteobacteria saw a significant increase, while Firmicutes experienced a noteworthy decrease in the GBM group. Moving down to the family level, we observed significantly elevated levels of Enterobacteriaceae, Bacteroidaceae, and Lachnospiraceae in GBM patients, while levels of Veillonellaceae, Rikenellaceae, and Prevotellaceae were notably lower. Delving into genera statistics, we noted a substantial increase in the abundance of Parasutterella, Escherichia-Shigella, and Bacteroides, alongside significantly lower levels of Ruminococcus 2, Faecalibacterium, and Prevotella_9 in the GBM group compared to the control group. Furthermore, when examining specific species, we found a significant increase in Bacteroides vulgatus and Escherichia coli in the GBM group. These observations collectively indicate a marked dysbiosis in the gut microbial composition of GBM patients. Additionally, the GBM group exhibited notably higher levels of alpha diversity when compared to the control group. This increase in diversity suggests a significant bacterial overgrowth in the gut of GBM patients in contrast to the controls. As a result, this research opens up potential avenues to gain a better understanding of the underlying mechanisms, pathways, and potential treatments for GBM, stemming from the significant implications of gut microbial dysbiosis in these patients.

MUC17 is an essential small intestinal glycocalyx component that is disrupted in Crohn's disease

Crohn's disease (CD) is the chronic inflammation of the ileum and colon triggered by bacteria, but insights into molecular perturbations at the bacteria-epithelium interface are limited. We report that membrane mucin MUC17 protects small intestinal enterocytes against commensal and pathogenic bacteria. In non-inflamed CD ileum, reduced MUC17 levels correlated with a compromised glycocalyx, allowing bacterial contact with enterocytes. Muc17 deletion in mice rendered the small intestine prone to atypical infection while maintaining resistance to colitis. The loss of Muc17 resulted in spontaneous deterioration of epithelial homeostasis and extra-intestinal translocation of bacteria. Finally, Muc17-deficient mice harbored specific small intestinal bacterial taxa observed in CD. Our findings highlight MUC17 as an essential line of defense in the small intestine with relevance for early epithelial defects in CD.

A non-invasive method to sample immune cells in the lower female genital tract using menstrual discs

T cells in the human female genital tract (FGT) 2 are key mediators of susceptibility to and protection from infection, including HIV and other sexually transmitted infections. There is a critical need for increased understanding of the distribution and activation of T cell populations in the FGT, but current sampling methods require a healthcare provider and are expensive, limiting the ability to study these populations longitudinally. To address these challenges, we have developed a method to sample immune cells from the FGT utilizing disposable menstrual discs which are non-invasive, self-applied, and low-cost. To demonstrate reproducibility, we sampled the cervicovaginal fluid (CVF) 3 of healthy, reproductive-aged individuals using menstrual discs over three sequential days. CVF was processed for cervicovaginal cells, and high parameter flow cytometry was used to characterize immune populations. We identified large numbers of live, CD45+ leukocytes, as well as distinct populations of T cells and B cells. Within the T cell compartment, activation and suppression status of T cell subsets were consistent with previous studies of the FGT utilizing current approaches, including identification of both tissue resident and migratory populations. In addition, the T cell population structure was highly conserved across days within individuals but divergent across individuals. Our approach to sample immune cells in the FGT with menstrual discs will decrease barriers to participation and empower longitudinal sampling in future research studies.

Gut bacteriome in inflammatory bowel disease: An update on recent advances

Inflammatory bowel diseases (IBD) are chronic inflammatory gut disorders, majorly classified as ulcerative colitis and Crohn's disease. The complex, multifactorial etiopathogenesis of IBD involves genetic predisposition, environmental cues, aberrant mucosal immune response and a disturbed gut microbiota. Epidemiological trends, studies in gnotobiotic mice models and genome-wide association studies, identifying genes involved in microbial handling, together mount evidence in support of the gut microbiota playing a pivotal role in IBD pathogenesis. Both Crohn's disease and ulcerative colitis are characterized by severe dysbiosis of the gut microbiome, marked by an expansion of detrimental taxa and concomitant depletion of beneficial members. IBD is characterized by reduction in abundances of bacterial genera involved in production of short-chain fatty acids, bio-transformations of bile acids and synthesis of indole-based tryptophan compounds such as Faecalibacterium, Ruminococcus, Coprococcus, Dorea, Parabacteroides, Eubacterium, Oscillibacter and Prevotella and elevation in members of phyla Proteobacteria and Actinobacteria. This imbalance not only results in exaggerated immune signaling towards the microbial antigens, but also results in an altered metabolomic milieu that triggers additional inflammatory cascades. The present review provides insights into the bacterial dysbiosis observed across different intestinal sites and their metabolomic imprints participating in IBD.

A Noninvasive Method to Sample Immune Cells in the Lower Female Genital Tract Using Menstrual Discs

T cells in the human female genital tract (FGT) are key mediators of susceptibility to and protection from infection, including HIV and other sexually transmitted infections. There is a critical need for increased understanding of the distribution and activation of T cell populations in the FGT, but current sampling methods require a healthcare provider and are expensive, limiting the ability to study these populations longitudinally. To address these challenges, we have developed a method to sample immune cells from the FGT utilizing disposable menstrual discs which are noninvasive, self-applied, and low in cost. To demonstrate reproducibility, we sampled the cervicovaginal fluid of healthy, reproductive-aged individuals using menstrual discs across 3 sequential days. Cervicovaginal fluid was processed for cervicovaginal cells, and high-parameter flow cytometry was used to characterize immune populations. We identified large numbers of live, CD45+ leukocytes, as well as distinct populations of T cells and B cells. Within the T cell compartment, activation and suppression status of T cell subsets were consistent with previous studies of the FGT utilizing current approaches, including identification of both tissue-resident and migratory populations. In addition, the T cell population structure was highly conserved across days within individuals but divergent across individuals. Our approach to sample immune cells in the FGT with menstrual discs will decrease barriers to participation and empower longitudinal sampling in future research studies.

The attenuating effect of fermented soymilk on DSS-induced colitis in mice by suppressing immune response and modulating gut microbiota

Fermented soymilk (FSM) as a new plant-based yoghurt has attracted attention for its nutritional and health benefits. The aim of this research is to explore the effect of consuming FSM before and during inflammatory bowel disease (IBD) on intestinal immune response, and to assess whether fermentation and sucrose can improve the anti-inflammatory activity of soymilk (SM) and FSM, and finally clarify their effect on the gut microbiota and levels of short-chain fatty acids (SCFAs). Consuming FSM in advance can effectively alleviate weight loss and bloody stools in mice with colitis and is associated with a 27% colon length repair rate. It can also prevent spleen and liver enlargement, inhibit immune response and oxidative stress, and increase the expression of the tight junction protein occludin gene (60%). Meanwhile, intaking FSM during IBD reduced weight loss, prevented liver damage, and repaired colon injury. In addition, fermentation enhance the inhibitory effects of FSM on colitis, whereas adding 3% sucrose to FSM had no effect on its intervention in colitis. Analysis of the composition of the gut microbiota in mice showed that the intake of FSM reduced the relative abundance of the pathogenic bacteria Parasutterella, Turicibater, and Bacteroide by 75%, 62%, and 50%, respectively, and increased the relative abundance of the beneficial bacteria Akkermansiaceae, Lachnospiraceae, Alloprevotella, and Dubosella by 28%, 50%, 80%, and 63%, respectively. It further restored the levels of SCFAs in the mouse intestine. The results provide a scientific basis for FSM as a natural anti-inflammatory food that can improve inflammatory intestinal microbiota imbalance and promote gut health.

Early life exposure to broccoli sprouts confers stronger protection against enterocolitis development in an immunological mouse model of inflammatory bowel disease

IMPORTANCE

To our knowledge, IL-10-KO mice have not previously been used to investigate the interactions of host, microbiota, and broccoli, broccoli sprouts, or broccoli bioactives in resolving symptoms of CD. We showed that a diet containing 10% raw broccoli sprouts increased the plasma concentration of the anti-inflammatory compound sulforaphane and protected mice to varying degrees against disease symptoms, including weight loss or stagnation, fecal blood, and diarrhea. Younger mice responded more strongly to the diet, further reducing symptoms, as well as increased gut bacterial richness, increased bacterial community similarity to each other, and more location-specific communities than older mice on the diet intervention. Crohn's disease disrupts the lives of patients and requires people to alter dietary and lifestyle habits to manage symptoms. The current medical treatment is expensive with significant side effects, and a dietary intervention represents an affordable, accessible, and simple strategy to reduce the burden of symptoms.

Multi-omics analysis revealing the interplay between gut microbiome and the host following opioid use

Opioid crisis is an ongoing epidemic since the past several decades in the United States. Opioid use-associated microbial dysbiosis is emerging as a key regulator of intestinal homeostasis and behavioral responses to opioid. However, the mechanistic insight into the role of microbial community in modulating host response is unavailable. To uncover the role of opioid-induced dysbiosis in disrupting intestinal homeostasis we utilized whole genome sequencing, untargeted metabolomics, and mRNA sequencing to identify changes in microbiome, metabolome, and host transcriptome respectively. Morphine treatment resulted in significant expansion of Parasuterella excrementihominis, Burkholderiales bacterium 1_1_47, Enterococcus faecalis, Enterorhabdus caecimuris and depletion of Lactobacillus johnsonii. These changes correlated with alterations in lipid metabolites and flavonoids. Significant alteration in microbial metabolism (metabolism of lipids, amino acids, vitamins and cofactors) and increased expression of virulence factors and biosynthesis of lipopolysaccharides (LPS) and lipoteichoic acid (LTA) were observed in microbiome of morphine-treated animals. In concurrence with changes in microbiome and metabolome extensive changes in innate and adaptive immune response, lipid metabolism, and gut barrier dysfunction were observed in the host transcriptome. Microbiome depleted mice displayed lower levels of inflammation, immune response and tissue destruction compared to mice harboring a dysbiotic microbiome in response to morphine treatment, thus establishing dysbiotic microbiome as mediator of morphine gut pathophysiology. Integrative analysis of multi-omics data highlighted the associations between Parasutterella excrementihominis, Burkholderiales bacterium 1_1_47, Enterococcus faecalis, Enterorhabdus caecimuris and altered levels of riboflavin, flavonoids, and lipid metabolites including phosphocholines, carnitines, bile acids, and ethanolamines with host gene expression changes involved in inflammation and barrier integrity of intestine. Omic analysis also highlighted the role of probiotic bacteria Lactobacillus johnsonii, metabolites flavonoids and riboflavin that were depleted with morphine as important factors for intestinal homeostasis. This study presents for the first time ever an interactive view of morphine-induced changes in microbial metabolism, strain level gut microbiome analysis and comprehensive view of changes in gut transcriptome. We also identified areas of potential therapeutic interventions to limit microbial dysbiosis and present a unique resource to the opioid research community.

Lactiplantibacillus plantarum CCFM8661 alleviates D-galactose-induced brain aging in mice by the regulation of the gut microbiota

Aging is characterized by a decline in biological functions, leading to various health issues. There is significant interest in mitigating age and age-related health issues. Gut microbiota has emerged as a crucial target for combating aging and influencing host health. This study evaluated the anti-aging effects of Lactiplantibacillus plantarum CCFM8661 in mice and the role of the gut microbiota in mediating its effects. Aging was induced in mice using D-galactose, and L. plantarum CCFM8661 was orally administered for 8 weeks to evaluate its effects on age-related decline and the gut microbiota. The results demonstrated that supplementation with L. plantarum CCFM8661 effectively alleviated cognitive impairment and oxidative stress in the aging brain, as well as liver oxidation and bone damage, and impaired intestinal barrier function in aging mice. Furthermore, L. plantarum CCFM8661 modulated the gut microbiota of aging mice, increasing the abundance of beneficial bacteria, such as Ruminococcaceae, and influenced the functionality of the gut microbiota to promote the production of active metabolites. These findings suggest that L. plantarum CCFM8661 has a mitigating effect on organismal aging, especially brain aging.

Exploring the Association between Gut Microbiota and Inflammatory Skin Diseases: A Two-Sample Mendelian Randomization Analysis

Emerging research underscores the substantial link between gut flora and various inflammatory skin diseases. We hypothesize that there exists a complex gut-skin axis, possibly affecting the progression of conditions such as eczema, acne, psoriasis, and rosacea. However, the precise nature of the causal connection between gut flora and skin diseases remains unestablished. In this study, we started by compiling summary data from genome-wide association studies (GWAS) featuring 211 unique gut microbiota and four types of skin conditions. We scrutinized these data across different taxonomic strata. Subsequently, we leveraged Mendelian randomization (MR) to ascertain if there is a causal link between gut microbiota and these skin conditions. We also performed a bidirectional MR analysis to identify the causality's direction. By utilizing Mendelian randomization, we identified 26 causal connections between the gut microbiome and four recognized inflammatory skin conditions, including 9 positive and 17 negative causal directions. Additional sensitivity analyses of these results revealed no evidence of pleiotropy or heterogeneity. Our MR analysis suggests a causal connection between gut microbiota and skin diseases, potentially providing groundbreaking perspectives for future mechanistic and clinical studies on microbiota-affected skin conditions.

Effects of Lipopolysaccharide and Deoxynivalenol on the Survival, Antioxidant and Immune Response, and Histopathology of Crayfish (Procambarus clarkii)

Bacterial lipopolysaccharide (LPS) in the aquatic environment has been reported to cause diseases in red swamp crayfish (Procambarus clarkii). In addition, deoxynivalenol (DON) is one of the primary mycotoxins found in aquaculture. However, the potential synergistic toxic effects of LPS and DON on crayfish are yet to be fully elucidated. In this study, crayfish were exposed to LPS (1 mg kg-1), DON (3 mg kg-1), and their combination (1 mg kg-1 LPS + 3 mg kg-1 DON, L+D) for a duration of six days. Co-exposure to LPS and DON exhibited the lowest survival rate compared to the control or individual treatments with LPS or DON alone. In the initial stage of the experiment, the combined treatment of LPS and DON showed a more pronounced up-regulation of antioxidant and immune-related enzymes in the sera compared to the other treatment groups, with a fold change ranging from 1.3 to 15. In addition, the (L+D) treatment group showed a down-regulation of immune-related genes, as well as Toll pathway-related genes in the hepatopancreas compared to LPS or DON. Moreover, the (L+D) treatment group demonstrated a 100% incidence of histopathological changes in the hepatopancreas, which were significantly more severe compared to the other three groups. In conclusion, our study provides physiological and histopathological evidence that the co-exposure to LPS and DON exerted synergistic toxic effects on crayfish. The observed effects could potentially hinder the development of the crayfish aquaculture industry in China.

Using the collaborative cross to identify the role of host genetics in defining the murine gut microbiome

BACKGROUND

The human gut microbiota is a complex community comprised of trillions of bacteria and is critical for the digestion and absorption of nutrients. Bacterial communities of the intestinal microbiota influence the development of several conditions and diseases. We studied the effect of host genetics on gut microbial composition using Collaborative Cross (CC) mice. CC mice are a panel of mice that are genetically diverse across strains, but genetically identical within a given strain allowing repetition and deeper analysis than is possible with other collections of genetically diverse mice.

RESULTS

16S rRNA from the feces of 167 mice from 28 different CC strains was sequenced and analyzed using the Qiime2 pipeline. We observed a large variance in the bacterial composition across CC strains starting at the phylum level. Using bacterial composition data, we identified 17 significant Quantitative Trait Loci (QTL) linked to 14 genera on 9 different mouse chromosomes. Genes within these intervals were analyzed for significant association with pathways and the previously known human GWAS database using Enrichr analysis and Genecards database. Multiple host genes involved in obesity, glucose homeostasis, immunity, neurological diseases, and many other protein-coding genes located in these regions may play roles in determining the composition of the gut microbiota. A subset of these CC mice was infected with Salmonella Typhimurium. Using infection outcome data, an increase in abundance of genus Lachnospiraceae and decrease in genus Parasutterella correlated with positive health outcomes after infection. Machine learning classifiers accurately predicted the CC strain and the infection outcome using pre-infection bacterial composition data from the feces.

CONCLUSION

Our study supports the hypothesis that multiple host genes influence the gut microbiome composition and homeostasis, and that certain organisms may influence health outcomes after S. Typhimurium infection. Video Abstract.

Early life exposure to broccoli sprouts confers stronger protection against enterocolitis development in an immunological mouse model of inflammatory bowel disease

Crohn's Disease (CD) is a presentation of Inflammatory Bowel Disease (IBD) that manifests in childhood and adolescence, and involves chronic and severe enterocolitis, immune and gut microbiome dysregulation, and other complications. Diet and gut-microbiota-produced metabolites are sources of anti-inflammatories which could ameliorate symptoms. However, questions remain on how IBD influences biogeographic patterns of microbial location and function in the gut, how early life transitional gut communities are affected by IBD and diet interventions, and how disruption to biogeography alters disease mediation by diet components or microbial metabolites. Many studies on diet and IBD use a chemically induced ulcerative colitis model, despite the availability of an immune-modulated CD model. Interleukin-10-knockout (IL-10-KO) mice on a C57BL/6 background, beginning at age 4 or 7 weeks, were fed a control diet or one containing 10% (w/w) raw broccoli sprouts, which was high in the sprout-sourced anti-inflammatory sulforaphane. Diets began 7 days prior to, and for 2 weeks after inoculation with Helicobacter hepaticus, which triggers Crohn's-like symptoms in these immune-impaired mice. The broccoli sprout diet increased sulforaphane in plasma; decreased weight stagnation, fecal blood, and diarrhea associated; and increased microbiota richness in the gut, especially in younger mice. Sprout diets resulted in some anatomically specific bacteria in younger mice, and reduced the prevalence and abundance of pathobiont bacteria which trigger inflammation in the IL-10-KO mouse, for example; Escherichia coli and Helicobacter. Overall, the IL-10-KO mouse model is responsive to a raw broccoli sprout diet and represents an opportunity for more diet-host-microbiome research.

Gamma-delta T cells modulate the microbiota and fecal micro-RNAs to maintain mucosal tolerance

BACKGROUND

Gamma-delta (γδ) T cells are a major cell population in the intestinal mucosa and are key mediators of mucosal tolerance and microbiota composition. Little is known about the mechanisms by which intestinal γδ T cells interact with the gut microbiota to maintain tolerance.

RESULTS

We found that antibiotic treatment impaired oral tolerance and depleted intestinal γδ T cells, suggesting that the gut microbiota is necessary to maintain γδ T cells. We also found that mice deficient for γδ T cells (γδ^-/-) had an altered microbiota composition that led to small intestine (SI) immune dysregulation and impaired tolerance. Accordingly, colonizing WT mice with γδ^-/- microbiota resulted in SI immune dysregulation and loss of tolerance whereas colonizing γδ^-/- mice with WT microbiota normalized mucosal immune responses and restored mucosal tolerance. Moreover, we found that SI γδ T cells shaped the gut microbiota and regulated intestinal homeostasis by secreting the fecal micro-RNA let-7f. Importantly, oral administration of let-7f to γδ^-/- mice rescued mucosal tolerance by promoting the growth of the γδ^-/--microbiota-depleted microbe Ruminococcus gnavus.

CONCLUSIONS

Taken together, we demonstrate that γδ T cell-selected microbiota is necessary and sufficient to promote mucosal tolerance, is mediated in part by γδ T cell secretion of fecal micro-RNAs, and is mechanistically linked to restoration of mucosal immune responses. Video Abstract.

Impact of Plasticizer on the Intestinal Epithelial Integrity and Tissue-Repairing Ability within Cells in the Proximity of the Human Gut Microbiome

Toxicological research into the impact of plasticizer on different organs has been reported in the past few decades, while their effects on shifting the gut microbiota and immune cells homeostasis in zebrafish were only studied recently. However, studies on the impact of plasticizer on human gut microbiota are scarce. In this study, we co-incubated healthy human fecal microbiota with different concentrations of Di(2-ethylhexyl) phthalate (DEHP) and di-iso-nonyl phthalate (DINP), analyzed microbial composition by 16S rDNA sequencing, and compared the influence of their derived microbiomes on the human enterocyte (HT-29) and murine macrophage (RAW264.7) cell lines. Microbial diversity is reduced by DEHP treatment in a dose-dependent manner. DEHP treatment reduced the phyla Firmicutes/Bacteroidetes ratio, while DINP treatment promoted Proteobacteria. Expressions of tight/adherens junction genes in HT-29 and anti-inflammatory genes in RAW264.7 were down-regulated by plasticizer-co-incubated microbiota derived metabolites. Overall, it is observed that selected plasticizers at high dosages can induce compositional changes in human microbiota. Metabolites from such altered microbiota could affect the tight junction integrity of the intestinal epithelium and upset macrophage differentiation homeostasis in proximity. Chronic exposure to these plasticizers may promote risks of dysbiosis, leaky gut or the exacerbation of intestinal inflammation.

Alginate Oligosaccharides Prevent Dextran-Sulfate-Sodium-Induced Ulcerative Colitis via Enhancing Intestinal Barrier Function and Modulating Gut Microbiota

Alginate oligosaccharides are degradation products of alginate and have attracted increasing attention due to their versatile biological functions. In the present study, C57BL/6 mice were used to assess the ameliorative effects and mechanisms of guluronate oligosaccharides (GAOS), mannuronic oligosaccharides (MAOS), and heterozygous alginate oligosaccharides (HAOS), which are the three alginate oligosaccharides of dextran sulfate sodium (DSS)-induced ulcerative colitis. The study showed that alginate oligosaccharides alleviated pathological histological damage by slowing down weight loss, inhibiting colonic length shortening, and reducing disease activity index (DAI) and histopathological scores. Alginate oligosaccharides modulated the colonic inflammatory response by reducing colonic MPO levels and downregulating the expression of IL-6 and IL-1β. Alginate oligosaccharides reduced intestinal permeability and reversed intestinal barrier damage by increasing the number of goblet cells, decreasing LPS levels, downregulating Bax protein levels, upregulating Bcl-2 protein levels, and enhancing the expression of the E-cadherin. Furthermore, alginate oligosaccharides modulated the composition of the gut microbiota and restored the production of short-chain fatty acids (SCFAs), especially acetate and butyrate. In conclusion, our study provides a scientific basis for the role of alginate oligosaccharides in relieving ulcerative colitis.

Disruption of the Gut Microbiota Confers Cisplatin Resistance in Epithelial Ovarian Cancer

Epithelial ovarian cancer (EOC) is the leading cause of gynecologic cancer death. Despite initial responses to intervention, up to 80% of patient tumors recur and require additional treatment. Retrospective clinical analysis of patients with ovarian cancer indicates antibiotic use during chemotherapy treatment is associated with poor overall survival. Here, we assessed whether antibiotic (ABX) treatment would impact growth of EOC and sensitivity to cisplatin. Immunocompetent or immunocompromised mice were given untreated control or ABX-containing (metronidazole, ampicillin, vancomycin, and neomycin) water prior to intraperitoneal injection with EOC cells, and cisplatin therapy was administered biweekly until endpoint. Tumor-bearing ABX-treated mice exhibited accelerated tumor growth and resistance to cisplatin therapy compared with control treatment. ABX treatment led to reduced apoptosis, increased DNA damage repair, and enhanced angiogenesis in cisplatin-treated tumors, and tumors from ABX-treated mice contained a higher frequency of cisplatin-augmented cancer stem cells than control mice. Stool analysis indicated nonresistant gut microbial species were disrupted by ABX treatment. Cecal transplants of microbiota derived from control-treated mice was sufficient to ameliorate chemoresistance and prolong survival of ABX-treated mice, indicative of a gut-derived tumor suppressor. Metabolomics analyses identified circulating gut-derived metabolites that were altered by ABX treatment and restored by recolonization, providing candidate metabolites that mediate the cross-talk between the gut microbiome and ovarian cancer. Collectively, these findings indicate that an intact microbiome functions as a tumor suppressor in EOC, and perturbation of the gut microbiota with ABX treatment promotes tumor growth and suppresses cisplatin sensitivity.

SIGNIFICANCE

Restoration of the gut microbiome, which is disrupted following antibiotic treatment, may help overcome platinum resistance in patients with epithelial ovarian cancer. See related commentary by Hawkins and Nephew, p. 4511.

Microalgae oil from Schizochytrium sp. alleviates obesity and modulates gut microbiota in high-fat diet-fed mice

Omega-3 PUFAs rich in fish oil are believed to prevent obesity by improving lipid metabolism and regulating gut microbiota. Microalgae oil is considered as an alternative source of omega-3 PUFAs owing to diminishing fish resources. Schizochytrium microalgae oil (SMO), with a high DHA proportion, is a promising source for commercial DHA production. However, its weight-loss and gut microbiota-regulating properties are not well studied. Here we compared the obesity reducing effects of SMO, commercial fish oil (FO) and a weight-loss drug, Orlistat (OL), in a high-fat diet (HFD) induced obesity mouse model. We found that SMO is comparable to commercial FO and OL with regard to weight loss, and it even exhibits the weight-loss effects earlier than FO and OL. It can efficiently inhibit the expression of lipogenesis-related genes and induce the expression of lipolysis-related genes. Moreover, SMO has different gut microbiota modulating effects from those of FO and OL. It does not influence the diversity of bacterial community, but does increase the abundance of several beneficial SCFAs-producing bacteria and inhibits obesity-promoting Desulfovibrio and several pathogens. We also found that SMO recovers the HFD-disturbed metabolic capability of gut microbiota. It can increase the abundance of several metabolism-related pathways, such as those of amino acids, SCFAs and bile acid, and decrease the level of the LPS biosynthesis pathway, which probably contributes to an improvement of lipid metabolism and restoration of the colonic mucosal barrier impaired by HFD. Our data suggest that SMO can be used as a superior dietary supplement for alleviating obesity.

Hydrolysates containing xylooligosaccharides produced by different strategies: Structural characterization, antioxidant and prebiotic activities

This study explores the structural characterization, antioxidant and prebiotic activities of hydrolysates containing xylooligosaccharides (XOS) produced by different strategies: direct fermentation of beechwood xylan (FermBX) and enzymatic treatment of beechwood (EnzBX) and rice husk (EnzRH) xylans. EnzBX and EnzRH showed XOS with a backbone of (1 → 4)-linked-xylopyranosyl residues and branches of arabinose, galactose, and uronic acids. FermBX presented the highest content of total phenolic compounds (14 mg GAE/g) and flavonoids (0.6 mg QE/g), which may contribute to its antioxidant capacity -39.1 μmol TE/g (DPPH), 45.7 μmol TE/g (ABTS), and 79.9 μmol Fe II/g (FRAP). The fermentation of hydrolysates decreased the abundance of microorganisms associated with intestinal diseases from Eubacteriales, Desulfovibrionales and Methanobacteriales orders, while stimulating the growth of organisms belonging to Bacteroides, Megamonas and Limosilactobacillus genera. The production of short-chain fatty acids, ammonia, and CO₂ suggested the prebiotic potential. In conclusion, hydrolysates without previous purification and obtained from non-chemical approaches demonstrated promising biological activities for further food applications.

Crohn's disease in endoscopic remission, obesity, and cases of high genetic risk demonstrates overlapping shifts in the colonic mucosal-luminal interface microbiome

BACKGROUND

Crohn's disease (CD) patients demonstrate distinct intestinal microbial compositions and metabolic characteristics compared to unaffected controls. However, the impact of inflammation and underlying genetic risk on these microbial profiles and their relationship to disease phenotype are unclear. We used lavage sampling to characterize the colonic mucosal-luminal interface (MLI) microbiome of CD patients in endoscopic remission and unaffected controls relative to obesity, disease genetics, and phenotype.

METHODS

Cecum and sigmoid colon were sampled from 110 non-CD controls undergoing screening colonoscopy who were stratified by body mass index and 88 CD patients in endoscopic remission (396 total samples). CD polygenic risk score (GRS) was calculated using 186 known CD variants. MLI pellets were analyzed by 16S ribosomal RNA gene sequencing, and supernatants by untargeted liquid chromatography-mass spectrometry.

RESULTS

CD and obesity were each associated with decreased cecal and sigmoid MLI bacterial diversity and distinct bacterial composition compared to controls, including expansion of Escherichia/Shigella. Cecal and sigmoid dysbiosis indices for CD were significantly greater in obese controls than non-overweight controls. CD, but not obesity, was characterized by altered biogeographic relationship between the sigmoid and cecum. GRS was associated with select taxonomic shifts that overlapped with changes seen in CD compared to controls including Fusobacterium enrichment. Stricturing or penetrating Crohn's disease behavior was characterized by lower MLI bacterial diversity and altered composition, including reduced Faecalibacterium, compared to uncomplicated CD. Taxonomic profiles including reduced Parasutterella were associated with clinical disease progression over a mean follow-up of 3.7 years. Random forest classifiers using MLI bacterial abundances could distinguish disease state (area under the curve (AUC) 0.93), stricturing or penetrating Crohn's disease behavior (AUC 0.82), and future clinical disease progression (AUC 0.74). CD patients showed alterations in the MLI metabolome including increased cholate:deoxycholate ratio compared to controls.

CONCLUSIONS

Obesity, CD in endoscopic remission, and high CD genetic risk have overlapping colonic mucosal-luminal interface (MLI) microbiome features, suggesting a shared microbiome contribution to CD and obesity which may be influenced by genetic factors. Microbial profiling during endoscopic remission predicted Crohn's disease behavior and progression, supporting that MLI sampling could offer unique insight into CD pathogenesis and provide novel prognostic biomarkers.

Murine in utero exposure to simulated complex urban air pollution disturbs offspring gut maturation and microbiota during intestinal suckling-to-weaning transition in a sex-dependent manner

Background

Emerging data indicate that prenatal exposure to air pollution may lead to higher susceptibility to several non-communicable diseases. Limited research has been conducted due to difficulties in modelling realistic air pollution exposure. In this study, pregnant mice were exposed from gestational day 10–17 to an atmosphere representative of a 2017 pollution event in Beijing, China. Intestinal homeostasis and microbiota were assessed in both male and female offspring during the suckling-to-weaning transition.

Results

Sex-specific differences were observed in progeny of gestationally-exposed mice. In utero exposed males exhibited decreased villus and crypt length, vacuolation abnormalities, and lower levels of tight junction protein ZO-1 in ileum. They showed an upregulation of absorptive cell markers and a downregulation of neonatal markers in colon. Cecum of in utero exposed male mice also presented a deeply unbalanced inflammatory pattern. By contrast, in utero exposed female mice displayed less severe intestinal alterations, but included dysregulated expression of Lgr5 in colon, Tjp1 in cecum, and Epcam, Car2 and Sis in ileum. Moreover, exposed female mice showed dysbiosis characterized by a decreased weighted UniFrac β-diversity index, a higher abundance of Bacteroidales and Coriobacteriales orders, and a reduced Firmicutes/Bacteroidetes ratio.

Conclusion

Prenatal realistic modelling of an urban air pollution event induced sex-specific precocious alterations of structural and immune intestinal development in mice.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12989-022-00481-y.

Exposure to atmospheric Ag, TiO2, Ti and SiO2 engineered nanoparticles modulates gut inflammatory response and microbiota in mice

The development of nanotechnologies is leading to greater abundance of engineered nanoparticles (EN) in the environment, including in the atmospheric air. To date, it has been shown that the most prevalent EN found in the air are silver (Ag), titanium dioxide (TiO₂), titanium (Ti), and silicon dioxide (SiO₂). As the intestinal tract is increasingly recognized as a target for adverse effects induced by inhalation of air particles, the aim of this study was to assess the impact of these 4 atmospheric EN on intestinal inflammation and microbiota. We assessed the combined toxicity effects of Ag, Ti, TiO₂, and SiO₂ following a 28-day inhalation protocol in male and female mice. In distal and proximal colon, and in jejunum, EN mixture inhalation did not induce overt histological damage, but led to a significant modulation of inflammatory cytokine transcript abundance, including downregulation of Tnfα, Ifnγ, Il1β, Il17a, Il22, IL10, and Cxcl1 mRNA levels in male jejunum. A dysbiosis was observed in cecal microbiota of male and female mice exposed to the EN mixture, characterized by sex-dependent modulations of specific bacterial taxa, as well as sex-independent decreased abundance of the Eggerthellaceae family. Under dextran sodium sulfate-induced inflammatory conditions, exposure to the EN mixture increased the development of colitis in both male and female mice. Moreover, the direct dose-response effects of individual and mixed EN on gut organoids was studied and Ag, TiO₂, Ti, SiO₂, and EN mixture were found to generate specific inflammatory responses in the intestinal epithelium. These results indicate that the 4 most prevalent atmospheric EN could have the ability to disturb intestinal homeostasis through direct modulation of cytokine expression in gut epithelium, and by altering the inflammatory response and microbiota composition following inhalation.

A dietary carbohydrate - gut Parasutterella - human fatty acid biosynthesis metabolic axis in obesity and type 2 diabetes

Recent rodent microbiome experiments suggest that besides Akkermansia, Parasutterella sp. are important in type 2 diabetes and obesity development. In the present translational human study, we aimed to characterize Parasutterella in our European cross-sectional FoCus cohort (n = 1,544) followed by validation of the major results in an independent Canadian cohort (n = 438). In addition, we examined Parasutterella abundance in response to a weight loss intervention (n = 55). Parasutterella was positively associated with BMI and type 2 diabetes independently of the reduced microbiome α/β diversity and low-grade inflammation commonly found in obesity. Nutritional analysis revealed a positive association with the dietary intake of carbohydrates but not with fat or protein consumption. Out of 126 serum metabolites differentially detectable by untargeted HPLC-based MS-metabolomics, L-cysteine showed the strongest reduction in subjects with high Parasutterella abundance. This is of interest, since Parasutterella is a known high L-cysteine consumer and L-cysteine is known to improve blood glucose levels in rodents. Furthermore, metabolic network enrichment analysis identified an association of high Parasutterella abundance with the activation of the human fatty acid biosynthesis pathway suggesting a mechanism for body weight gain. This is supported by a significant reduction of the Parasutterella abundance during our weight loss intervention. Together, these data indicate a role for Parasutterella in human type 2 diabetes and obesity, whereby the link to L-cysteine might be relevant in type 2 diabetes development and the link to the fatty acid biosynthesis pathway for body weight gain in response to a carbohydrate-rich diet in obesity development.

Crocetin Prolongs Recovery Period of DSS-Induced Colitis via Altering Intestinal Microbiome and Increasing Intestinal Permeability

Crocetin is one of the major active constituents of saffron (Crocus sativus L.) which has a reputation for facilitating blood circulation and dispersing blood stasis in traditional Chinese medicine. However, there is little evidence showing the relationship between crocetin intake and the risk of gastrointestinal diseases such as colitis. In order to investigate the effect of crocetin on the regulation of intestinal barrier function and intestinal microbiota composition, mice were treated with crocetin after 3% dextran sulfate sodium (DSS) administration for one week. We found that crocetin intake at 10 mg/kg aggravated colitis in mice, showing increased weight loss and more serious histological abnormalities compared with the DSS group. The 16s rDNA sequencing analysis of the feces samples showed that mice treated with 10 mg/kg crocetin had lower species diversity and richness than those treated with DSS. At the genus level, a higher abundance of Akkermansia and Mediterraneibacter, and a lower abundance of Muribaculaceae, Dubosiella, Paramuribaculum, Parasutterella, Allobaculum, Duncaniella, Candidatus Stoquefichus, and Coriobacteriaceae UCG-002 were observed in the crocetin group. Untargeted metabolomic analyses revealed that crocetin reduced the levels of primary and secondary bile acids such as 12-ketodeoxycholic acid, 7-ketodeoxycholic acid, 3-sulfodeoxycholic acid, 6-ethylchenodeoxycholic acid, chenodeoxycholate, glycochenodeoxycholate-7-sulfate, glycocholate, and sulfolithocholic acid in the colon. In conclusion, crocetin intake disturbed intestinal homeostasis and prolonged recovery of colitis by promoting inflammation and altering gut microbiota composition and its metabolic products in mice. Our findings suggest that patients with gastrointestinal diseases such as inflammatory bowel disease should use crocetin with caution.

B-cell-depletion reverses dysbiosis of the microbiome in multiple sclerosis patients

To elucidate cross-sectional patterns and longitudinal changes of oral and stool microbiota in multiple sclerosis (MS) patients and the effect of B-cell depletion. We conducted an observational, longitudinal clinical cohort study analysing four timepoints over 12 months in 36 MS patients, of whom 22 initiated B-cell depleting therapy with ocrelizumab and a healthy control group. For microbiota analysis of the oral cavity and the gut, provided stool and oral swab samples underwent 16S rDNA sequencing and subsequent bioinformatic analyses. Oral microbiota-patterns exhibited a reduced alpha-diversity and unique differential microbiota changes compared to stool such as increased levels of Proteobacteria and decreased abundance of Actinobacteria. Following B-cell depletion, we observed increased alpha-diversity in the gut and the oral cavity as well as a long-term sustained reduction of pro-inflammatory Gram-negative bacteria (e.g., Escherichia/Shigella). MS patients have altered stool and oral microbiota diversity patterns compared to healthy controls, which are most pronounced in patients with higher disease activity and disability. Therapeutic B-cell depletion is associated with persisting regression of these changes. Whether these microbial changes are unspecific side-effects of B-cell depletion or indirectly modulate MS disease activity and progression is currently unknown and necessitates further investigations.

Anti-Osteoporotic Effect of Lactobacillus brevis AR281 in an Ovariectomized Mouse Model Mediated by Inhibition of Osteoclast Differentiation

Simple Summary

Osteoporosis-related fractures are among the most common complications found in postmenopausal adults, which results in considerable economic impacts. Most treatments for osteoporosis increase bone formation or decrease bone resorption. While estrogen replacement therapy may be the gold standard for the treatment of osteoporosis, it also carries an increased risk of cardiac events and strokes in women. Thus, it is important to seek a safe and effective treatment method. Gut homeostasis is demonstrably linked to bone health. Probiotics are widely known to modulate gut microbiota, but with large strain differences. Our findings showed a strain of Lactobacillus brevis AR281 with an anti-osteoporotic property in ovariectomized mice, which may provide a new way to prevent osteoporosis.

Abstract

Osteoporosis is a global disease characterized by weakened bone microarchitecture, leading to osteoporotic fractures. Estrogen replacement therapy is the traditional treatment for osteoporosis but carries with it an increased risk of cardiac events. In search of a safe and effective treatment, we used Lactobacillus brevis AR281, which has anti-inflammatory properties, to conduct a 7-week experiment, investigating its inhibitory effects on osteoporosis in an ovariectomized (ovx) mouse model. The results demonstrated that AR281 significantly improved bone microarchitecture and biomechanical strength in ovx mice by attenuating bone resorption. AR281 significantly decreased the critical osteoclast activator, the ratio of the receptor activator for nuclear factor kappa B (NF-κB) ligand (RANKL) to osteoprotegerin, and pro-inflammatory osteoclastogenic mediators, such as IL-1, IL-6, and IL-17, which can increase the RANKL expression. Moreover, AR281 modulated intestinal microbiota in ovx mice increased the abundance of Akkermansia, which is responsible for the improvement of gut epithelial barrier integrity. In an in vitro trial, AR281 suppressed the number of osteoclasts differentiated from the osteoclast precursor RAW264.7 cells caused by RANKL through the tumor necrosis factor (TNF) receptor-associated factor 6 (TRAF6)/NF-κB/nuclear factor of activated T cells c1 (NFATc1) pathway. Therefore, AR281 may be a natural alternative for combating osteoporosis.

The Attenuation of Chronic Ulcerative Colitis by (R)-salbutamol in Repeated DSS-Induced Mice

Racemic salbutamol ((RS)-sal), which consist of the same amount of (R)-sal and (S)-sal, has been used for asthma and COPD due to its bronchodilation effect. However, the effect of (R)-sal on repeated dextran sulfate sodium (DSS)-induced chronic colitis has not yet been investigated. In this study evaluated the potential effect of (R)-, (S)-, and (RS)-sal in mice with repeated DSS-induced chronic colitis and investigated the underlying mechanisms. Here, we verified that chronic colitis was significantly attenuated by (R)-sal, which was evidenced by notably mitigated body weight loss, disease activity index (DAI), splenomegaly, colonic lengths shortening, and histopathological scores. (R)-sal treatment noticeably diminished the levels of inflammatory cytokines (such as TNF-α, IL-6, IL-1β, and IFN-γ). Notably, the efficacy of (R)-sal was better than that of (RS)-sal. Further research revealed that (R)-sal mitigated colonic CD4 leukocyte infiltration, decreased NF-κB signaling pathway activation, improved the Nrf-2/HO-1 signaling pathway, and increased the expression of ZO-1 and occludin. In addition, (R)-sal suppressed the levels of TGF-β1, α-SMA, and collagen in mice with chronic colitis. Furthermore, the 16S rDNA sequences analyzed of the intestinal microbiome revealed that (R)-sal could mitigate the intestinal microbiome structure and made it more similar to the control group, which mainly by relieving the relative abundance of pathogens (such as Bacteroides) and increasing the relative abundance of probiotics (such as Akkermansia). Therefore, (R)-sal ameliorates repeated DSS-induced chronic colitis in mice by improving inflammation, suppressing oxidative stress, mitigating intestinal barrier function, relieving intestinal fibrosis, and regulating the intestinal microbiome community. These results indicate that (R)-sal maybe a novel treatment alternative for chronic colitis.

Mechanism of the Gut Microbiota Colonization Resistance and Enteric Pathogen Infection

The mammalian gut microbial community, known as the gut microbiota, comprises trillions of bacteria, which co-evolved with the host and has an important role in a variety of host functions that include nutrient acquisition, metabolism, and immunity development, and more importantly, it plays a critical role in the protection of the host from enteric infections associated with exogenous pathogens or indigenous pathobiont outgrowth that may result from healthy gut microbial community disruption. Microbiota evolves complex mechanisms to restrain pathogen growth, which included nutrient competition, competitive metabolic interactions, niche exclusion, and induction of host immune response, which are collectively termed colonization resistance. On the other hand, pathogens have also developed counterstrategies to expand their population and enhance their virulence to cope with the gut microbiota colonization resistance and cause infection. This review summarizes the available literature on the complex relationship occurring between the intestinal microbiota and enteric pathogens, describing how the gut microbiota can mediate colonization resistance against bacterial enteric infections and how bacterial enteropathogens can overcome this resistance as well as how the understanding of this complex interaction can inform future therapies against infectious diseases.

Bacterial Characteristics of Intestinal Tissues From Patients With Crohn's Disease

Background and Aims

It is believed that intestinal bacteria play an indispensable role in promoting intestinal inflammation. However, the characteristics of these tissue-associated bacteria remain elusive. The aim of this study is to explore the bacterial loads, compositions, and structures in the noninflamed mucosa, inflamed mucosa, and creeping fat taken from patients with Crohn’s disease (CD).

Methods

Noninflamed mucosa, inflamed mucosa, and creeping fat samples were obtained from 10 surgical patients suffering from CD. Total bacterial DNA was extracted in a sterile environment using aseptic techniques. The V3–V4 regions of bacterial 16S rDNA were amplified and analysed using standard microbiological methods. qPCR was used to confirm the change in abundance of specific species in additional 30 independent samples.

Results

Inflamed mucosa exhibited the highest bacterial load (3.8 and 12 times more than that of non-inflamed mucosa and creeping fat) and species diversity. The relative abundance of Proteobacteria was dominant in most samples and was negatively associated with Firmicutes. Moreover, the relative abundances of Methylobacterium and Leifsonia in creeping fat significantly increased more than twice as much as other tissue types. The bacterial community structure analysis showed that the bacterial samples from the same individual clustered more closely.

Conclusion

This study reveals the significant differences in bacterial load, species diversity, and composition among different intestinal tissue types of CD patients and confirms that the bacterial samples from the same individual are highly correlated. Our findings will shed light on fully revealing the characteristics of tissue-associated bacteria and their roles in CD pathogenesis.

Distinct microbiome profiles and biofilms in Leishmania donovani-driven cutaneous leishmaniasis wounds

The endemic strain of Leishmania donovani in Sri Lanka causes cutaneous leishmaniasis (CL) rather than more common visceral form. We have visualized biofilms and profiled the microbiome of lesions and unaffected skin in thirty-nine CL patients. Twenty-four lesions (61.5%) were biofilm-positive according to fluorescence in situ hybridization. Biopsies of biofilm-positive lesions were dominated by Pseudomonas, class Bacilli and Enterobacteriaceae and distinguished by significantly lower community evenness. Higher relative abundance of a class Bacilli OTU was detected in wound swabs versus contralateral skin. Wound swabs and biopsies had significantly distinct microbiome profiles and lower diversity compared to unaffected skin. Greater abundances of potentially pathogenic organisms were observed in wet ulcers, lesions with high parasite loads and large wounds. In summary, more than half of L. donovani associated CL wounds harboured biofilms and the wounds exhibited a distinct, less diverse, microbiome than unaffected skin.

The Use of Mushrooms and Spirulina Algae as Supplements to Prevent Growth Inhibition in a Pre-Clinical Model for an Unbalanced Diet

Today’s eating patterns are characterized by the consumption of unbalanced diets (UBDs) resulting in a variety of health consequences on the one hand, and the consumption of dietary supplements in order to achieve overall health and wellness on the other. Balanced nutrition is especially crucial during childhood and adolescence as these time periods are characterized by rapid growth and development of the skeleton. We show the harmful effect of UBD on longitudinal bone growth, trabecular and cortical bone micro-architecture and bone mineral density; which were analyzed by micro-CT scanning. Three point bending tests demonstrate the negative effect of the diet on the mechanical properties of the bone material as well. Addition of Spirulina algae or Pleurotus eryngii or Agaricus bisporus mushrooms, to the UBD, was able to improve growth and impaired properties of the bone. 16SrRNA Sequencing identified dysbiosis in the UBD rats’ microbiota, with high levels of pro-inflammatory associated bacteria and low levels of bacteria associated with fermentation processes and bone related mechanisms. These results provide insight into the connection between diet, the skeletal system and the gut microbiota, and reveal the positive impact of three chosen dietary supplements on bone development and quality presumably through the microbiome composition.

Bisphenol A impairs cognitive function and 5-HT metabolism in adult male mice by modulating the microbiota-gut-brain axis

Bisphenol A (BPA) has been found to promote hepatotoxicity, reproductive toxicity, and developmental toxicity. However, the neurotoxicity and mechanism of BPA on cognitive function are still unclear. To that end, eight-week-old adult male and female C57BL/6J mice were exposed to 0.05, 0.5, 5, and 50 mg/kg BPA by dietary supplementation for 22 weeks. BPA exposure impaired learning and memory in male mice, associated with increased neuroinflammation and damaged blood-brain barrier. BPA exposure reduced the tight junctions in the colon, resulting in dysfunction of the gut barrier. The levels of neurotransmitters in the serum, hippocampus, and colon of male mice, including tryptophan, 5-hydroxytryptamine (5-HT) and 5-hydroxyindoleacetic acid, were all decreased by BPA, together with reduced expression of tryptophan and 5-HT metabolism-related genes. Cecal microbiota analysis revealed that the diversity and composition of the microbiota in male mice were markedly altered by BPA, leading to functional profile changes in the microbial community. These results suggest that the neurotoxicity of BPA in male mice may be partly regulated by the interactions of the microbiota-gut-brain axis. However, BPA has little effect on the cognitive function in female mice, which might be caused by the microbial differences and the role of estrogen receptors.

Supplementation with Sucrosomial® iron leads to favourable changes in the intestinal microbiome when compared to ferrous sulfate in mice

Iron deficiency is one of the most common nutritional deficiencies worldwide and is often treated with oral iron supplements. However, commonly used supplements, including those based on ferrous iron salts, are associated with gastrointestinal side effects and unfavorable changes in the intestinal microbiome. Sucrosomial® iron is a novel iron formulation that is effective at treating iron deficiency, and with fewer gastrointestinal side effects, yet its effect on the gut microbiome has not been examined previously. Thus, we treated mice for two weeks with diets containing either Sucrosomial® iron or ferrous sulfate as the sole iron source and examined bacterial communities in the intestine using 16S Microbial Profiling of DNA extracted from feces collected both prior to and following dietary treatment. Mice treated with Sucrosomial® iron showed an increase in Shannon diversity over the course of the study. This was associated with a decrease in the abundance of the phylum Proteobacteria, which contains many pathogenic species, and an increase in short chain fatty acid producing bacteria such as Lachnospiraceae, Oscillibacter and Faecalibaculum. None of these changes were observed in mice treated with ferrous sulfate. These results suggest that Sucrosomial® iron may have a beneficial effect on the intestinal microbiome when compared to ferrous sulfate and that this form of iron is a promising alternative to ferrous iron salts for the treatment of iron deficiency.

Oral iron supplementation after antibiotic exposure induces a deleterious recovery of the gut microbiota

Background

Oral iron supplementation is commonly prescribed for anemia and may play an important role in the gut microbiota recovery of anemic individuals who received antibiotic treatment. This study aims to investigate the effects of iron supplementation on gut microbiota recovery after antibiotics exposure.

Results

Mice were subjected to oral antibiotic treatment with neomycin and metronidazole and were fed diets with different concentrations of iron. The composition of the gut microbiota was followed throughout treatment by 16S rRNA sequencing of DNA extracted from fecal samples. Gut microbiota functions were inferred using PICRUSt2, and short-chain fatty acid concentration in fecal samples was assessed by liquid-chromatography mass spectrometry. Iron supplementation after antibiotic exposure shifted the gut microbiota composition towards a Bacteroidetes phylum-dominant composition. At the genus level, the iron-supplemented diet induced an increase in the abundance of Parasutterella and Bacteroides, and a decrease of Bilophila and Akkermansia. Parasutterella excrementihominis, Bacteroides vulgatus, and Alistipes finegoldii, were more abundant with the iron excess diet. Iron-induced shifts in microbiota composition were accompanied by functional modifications, including an enhancement of the biosynthesis of primary bile acids, nitrogen metabolism, cyanoamino acid metabolism and pentose phosphate pathways. Recovery after antibiotic treatment increased propionate levels independent of luminal iron levels, whereas butyrate levels were diminished by excess iron.

Conclusions

Oral iron supplementation after antibiotic therapy in mice may lead to deleterious changes in the recovery of the gut microbiota. Our results have implications on the use of oral iron supplementation after antibiotic exposure and justify further studies on alternative treatments for anemia in these settings.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12866-021-02320-0.

Gut Microbiome Composition and Metabolic Status Are Differently Affected by Early Exposure to Unhealthy Diets in a Rat Model

Childhood is a critical stage of development during which diet can have profound influence on the microbiota–host interactions, leading to potentially lifelong impacts. This study aimed to investigate whether the consumption of cafeteria diet (CAFD) and sugary drinks during early rat life alters the structure of the gut microbial community and the metabolic activity. Four-week-old male Wistar rats (n = 27) were fed a standard chow diet with ad libitum access to water (CD) or to sucrose solution (HSD), and a third group was fed with CAFD and a sucrose solution for 14 weeks. HSD and CAFD consumption induced alterations in Firmicutes to Bacteroidetes ratio, Proteobacteria, and Verrucomicrobia. HSD increased the abundance of Barnesiella, whereas CAFD induced a depletion of Saccharibacteria. CAFD increased total white adipose tissue (WAT) weight (p < 0.0005) compared to CD. When CAFD was compared to HSD, a significant difference was found only for retroperitoneal WAT (p < 0.0005). Unhealthy diet-fed groups presented higher glucose (p < 0.0005), total cholesterol and creatinine serum levels (p < 0.005) compared to the CD rats. Early-life consumption of HSD, and of CAFD even more so, can have long-lasting negative effects on metabolic function. The gut microbiota communities were distinctively perturbed by diet composition.

Age and Giardia intestinalis Infection Impact Canine Gut Microbiota

Giardia intestinalis is a flagellated protozoan responsible for giardiosis (also called giardiasis in humans), the most prevalent and widespread parasitic infection in humans and mammals worldwide. The intestinal microbiota is highly diverse and any alteration in its composition may impact on the health of the host. While studies on the mouse model of giardiosis described the role of the gut microbiota in host susceptibility to infection by the parasite, little is known about the gut microbiota during natural infections in dogs and particularly in puppies. In this study, we monitored naturally G. intestinalis-infected puppies for 3 months and quantified cyst excretion every 2 weeks. All puppies remained subclinically infected during the sampling period as confirmed by fecal examination. In parallel, we performed 16S Illumina sequencing of fecal samples from the different time points to assess the impact of G. intestinalis infection on gut microbiota development of the puppies, as well as gut health markers of immunity such as fecal IgA and calprotectin. Sequencing results revealed that the canine fecal microbiota of Giardia-infected puppies becomes more complex and less diverse with increasing age. In addition, significant differences in the structure of the microbiota were observed between puppies with high and low Giardia cyst excretion. Chronic subclinical G. intestinalis infection appears to be associated with some detrimental structural changes in the gut microbiota. G. intestinalis-associated dysbiosis is characterized by an enrichment of facultative anaerobic, mucus-degrading, pro-inflammatory species and opportunistic pathogens, as well as a reduction of Lactobacillus johnsonii at specific time points. Calprotectin levels increased with age, suggesting the establishment of chronic low-grade inflammation in puppies. Further work is needed to demonstrate whether these alterations in the canine gut microbiota could lead to a dysbiosis-related disease, such as irritable bowel syndrome (IBS) or inflammatory bowel disease (IBD).

Tripartite relationship between gut microbiota, intestinal mucus and dietary fibers: towards preventive strategies against enteric infections

The human gut is inhabited by a large variety of microorganims involved in many physiological processes and collectively referred as to gut microbiota. Disrupted microbiome has been associated with negative health outcomes and especially could promote the onset of enteric infections. To sustain their growth and persistence within the human digestive tract, gut microbes and enteric pathogens rely on two main polysaccharide compartments, namely dietary fibers and mucus carbohydrates. Several evidences suggest that the three-way relationship between gut microbiota, dietary fibers and mucus layer could unravel the capacity of enteric pathogens to colonise the human digestive tract and ultimately lead to infection. The review starts by shedding light on similarities and differences between dietary fibers and mucus carbohydrates structures and functions. Next, we provide an overview of the interactions of these two components with the third partner, namely, the gut microbiota, under health and disease situations. The review will then provide insights into the relevance of using dietary fibers interventions to prevent enteric infections with a focus on gut microbial imbalance and impaired-mucus integrity. Facing the numerous challenges in studying microbiota-pathogen-dietary fiber-mucus interactions, we lastly describe the characteristics and potentialities of currently available in vitro models of the human gut.

Lactobacillus paracasei modulates the gut microbiota and improves inflammation in type 2 diabetic rats

This study aimed to investigate the effects of probiotic Lactobacillus paracasei NL41 on inflammation and the gut microbiota of type 2 diabetic (T2D) rats induced by high-fat diet (HFD) and low-dose streptozotocin (STZ). A T2D rat model was established by inducing Sprague-Dawley rats with HFD/STZ, followed by 12-weeks L. paracasei NL41 gavage. The blood, colonic tissues, and feces samples of these rats were collected for inflammation, histology, and intestinal microbiota profiling. L. paracasei NL41 treatment induced remarkable improvement in the inflammatory status by decreasing the levels of serum lipopolysaccharides (LPS), free fatty acids (FFA), tumor necrosis factor-α (TNF-α), interleukin (IL)-6, and IL-8 and increasing the level of IL-10. Gut barrier function was significantly protected in NL41-treated rats. Moreover, the strain NL41 induced changes in the microbiota structure and influenced the relative abundance of the key species. Specifically, Bacteroides, Clostridia (specifically, Ruminococcus torques), and Parasutterella were significantly reduced, while some beneficial microorganisms (Bacteroidales_S24-7_group and the families Lachnospiraceae and Ruminococcaceae) were enriched by NL41. The correlational analyses indicated that L. paracasei NL41 ameliorating inflammation was closely related to the key species of the gut microbiota. The present study indicates that probiotic L. paracasei NL41 decreases LPS-induced inflammation by improving the gut microbiota and preserving intestinal integrity.

Soil Sample Preservation Strategy Affects the Microbial Community Structure

Sample preservation is a critical procedure in any research that relies on molecular tools and is conducted in remote areas. Sample preservation options include low and room temperature storage, which require freezing equipment and specific buffering solutions, respectively. The aim of the present study was to investigate whether DNA/RNA Shield 1x from Zymo Research and DESS (Dimethyl sulfoxide, Ethylenediamine tetraacetic acid, Saturated Salt) solution performed similarly to snap freezing in liquid nitrogen. Soil samples were stored for 1 month in each of the buffers and without any solution at a range of temperatures: –20, +4, and +23°C. All treatments were compared to the “optimal treatment”, namely, snap freezing in liquid nitrogen. The quality and quantity of DNA were analyzed, and the microbial community structure was investigated in all samples. The results obtained indicated that the quantity and integrity of DNA was preserved well in all samples; however, the taxonomic distribution was skewed in samples stored without any solution at ambient temperatures, particularly when analyses were performed at lower taxonomic levels. Although both solutions performed equally well, sequencing output and OTU numbers in DESS-treated samples were closer to those snap frozen with liquid nitrogen. Furthermore, DNA/RNA Shield-stored samples performed better for the preservation of rare taxa.

Methylmercury Production and Degradation under Light and Dark Conditions in the Water Column of the Hells Canyon Reservoirs, USA

Methylmercury (MeHg) is a highly toxic form of mercury that can bioaccumulate in fish tissue. Methylmercury is produced by anaerobic bacteria, many of which are also capable of MeHg degradation. In addition, demethylation in surface waters can occur via abiotic sunlight-mediated processes. The goal of the present study was to understand the relative importance of microbial Hg methylation/demethylation and abiotic photodemethylation that govern the mass of MeHg within an aquatic system. The study location was the Hells Canyon complex of 3 reservoirs on the Idaho-Oregon border, USA, that has fish consumption advisories as a result of elevated MeHg concentrations. Our study utilized stable isotope addition experiments to trace MeHg formation and degradation within the water column of the reservoirs to understand the relative importance of these processes on the mass of MeHg using the Water Quality Analysis Simulation Program. The results showed that rates of MeHg production and degradation within the water column were relatively low (<0.07 d^-1 ) but sufficient to account for most of the MeHg observed with the system. Most MeHg production within the water column appeared to occur in the spring when much of the water column was in the processes of becoming anoxic. In the surface waters, rates of photodemethylation were relatively large (up to -0.25 d^-1 ) but quickly decreased at depths >0.5 m below the surface. These results can be used to identify the relative importance of MeHg processes that can help guide reservoir management decisions. Environ Toxicol Chem 2021;40:1829-1839. © 2021 SETAC. This article has been contributed to by US Government employees and their work is in the public domain in the USA.

Niche partitioning of bacterial communities along the stratified water column in the Black Sea

The Black Sea is the largest semi‐closed permanently anoxic basin on our planet with long‐term stratification. The study aimed at describing the Black Sea microbial community taxonomic and functional composition within the range of depths spanning across oxic/anoxic interface, and to uncover the factors behind both their vertical and regional differentiation. 16S rRNA gene MiSeq sequencing was applied to get the data on microbial community taxonomy, and the PICRUSt pipeline was used to infer their functional profile. The normoxic zone was mainly inhabited by primary producers and heterotrophic prokaryotes (e.g., Flavobacteriaceae, Rhodobacteraceae, Synechococcaceae) whereas the euxinic zone—by heterotrophic and chemoautotrophic taxa (e.g., MSBL2, Piscirickettsiaceae, and Desulfarculaceae). Assimilatory sulfate reduction and oxygenic photosynthesis were prevailing within the normoxic zone, while the role of nitrification, dissimilatory sulfate reduction, and anoxygenic photosynthesis increased in the oxygen‐depleted water column part. Regional differentiation of microbial communities between the Ukrainian shelf and offshore zone was detected as well, yet it was significantly less pronounced than the vertical one. It is suggested that regional differentiation within a well‐oxygenated zone is driven by the difference in phytoplankton communities providing various substrates for the prokaryotes, whereas redox stratification is the main driving force behind microbial community vertical structure.

Effects of Probiotic Supplementation on Short Chain Fatty Acids in the AppNL-G-F Mouse Model of Alzheimer's Disease

BACKGROUND

The intestinal microbiota and its metabolites, particularly short-chain fatty acids (SCFAs), have been implicated in immune function, host metabolism, and even behavior.

OBJECTIVE

This study was performed to investigate whether probiotic administration influences levels of intestinal microbiota and their metabolites in a fashion that may attenuate brain changes in a mouse model of Alzheimer's disease (AD).

METHODS

C57BL/6 wild-type (WT) mice were compared to AppNL-G-Fmice. The animals were treated with either vehicle or probiotic (VSL#3) for 8 weeks. Fecal microbiome analysis along with Aβ, GFAP, Iba-1, c-Fos, and Ki-67 immunohistochemistry was done. SCFAs were analyzed in serum and brains using UPLC-MS/MS.

RESULTS

Probiotic (VSL#3) supplementation for 2 months resulted in altered microbiota in both WT and AppNL-G-Fmice. An increase in serum SCFAs acetate, butyrate, and lactate were found in both genotypes following VSL#3 treatment. Propionate and isobutyrate were only increased in AppNL-G-Fmice. Surprisingly, VSL#3 only increased lactate and acetate in brains of AppNL-G-Fmice. No significant differences were observed between vehicle and VSL#3 fed AppNL-G-Fhippocampal immunoreactivities of Aβ, GFAP, Iba-1, and Ki-67. However, hippocampal c-Fos staining increased in VSL#3 fed AppNL-G-Fmice.

CONCLUSION

These data demonstrate intestinal dysbiosis in the AppNL-G-Fmouse model of AD. Probiotic VSL#3 feeding altered both serum and brain levels of lactate and acetate in AppNL-G-Fmice correlating with increased expression of the neuronal activity marker, c-Fos.

Impact of Olive Saplings and Organic Amendments on Soil Microbial Communities and Effects of Mineral Fertilization

Plant communities and fertilization may have an impact on soil microbiome. Most commercial olive trees are minerally fertilized, while this practice is being replaced by the use of organic amendments. Organic amendments can both fertilize and promote plant growth-promoting organisms. Our aims were (i) to describe the changes in soil bacterial and fungal communities induced by the presence of young olive trees and their interaction with organic amendments and (ii) to compare the effects of mineral and organic fertilization. We set up two parallel experiments in pots using a previously homogenized soil collected from a commercial olive orchard: in the first one, we grew olive saplings in unamended and organically amended soils with two distinct composts and compared these two soils incubated without a plant, while in the second experiment, we comparatively tested the effects of organic and mineral fertilization. OTUs and the relative abundances of bacterial and fungal genera and phyla were analyzed by 16S rRNA and ITS1 gene amplicon using high-throughput sequencing. Basal respiration and substrate-induced respiration were measured by MicroResp^TM. The effects of the different treatments were analyzed in all phyla and in the 100 most abundant genera. The presence of olive saplings increased substrate-induced respiration and bacterial and fungal richness and diversity. Organic amendments greatly affected both bacterial and fungal phyla and increased bacterial richness while not affecting fungal richness. Mineral fertilization increased the relative abundance of the less metabolically active bacterial phyla (Actinobacteria and Firmicutes), while it reduced the most metabolically active phylum, Bacteroidetes. Mineral fertilization increased the relative abundance of three N₂-fixing Actinobacteria genera, while organic fertilization only increased one genus of Proteobacteria. In organically and minerally fertilized soils, high basal respiration rates were associated with low fungal diversity. Basidiomycota and Chytridiomycota relative abundances positively correlated with basal respiration and substrate-induced respiration, while Ascomycota correlated negatively. Indeed, the Ascomycota phyla comprised most of the fungal genera decreased by organic amendments. The symbiotrophic phylum Glomeromycota did not correlate with any of the C sources. The relative abundance of this phylum was promoted by the presence of plants but decreased when amending soils with composts.

Microbiome analysis reveals gut microbiota alteration in mice with the effect of matrine

Mounting evidence revealed the negative effects of abuse of antibiotic including the induction of decreased immunity and dysbacteriosis. Matrine displayed multiple beneficial effects such as anti-inflammatory, antiviral and antibacterial, but studies of its influence on gut microbiota are still insufficient to report. Here, the present study was conducted to investigate the influence of matrine on the gut microbiota of mice and amoxicillin was used as a positive control. A total of 21 cecal samples were obtained from seven groups for high-throughput sequencing analysis based on V3-V4 variable region of 16S rRNA genes. Results revealed that the diversity and abundance of gut microbiota in mice gradually decreased with the increase of the concentration of amoxicillin, whereas matrine administration did not effect the intestinal microbial community structure. Additionally, amoxicillin and matrine supplementation also caused significant changes in the relative abundance of some intestinal bacteria. Specifically, the ratio of Klebsiella and Corynebacterium_1, Bacteroides and Parasutterella in the amoxicillin treated-group were increased as compared to the control group, whereas Muribaculaceae_unclassified, Alistipes and Lactobacillus were significantly decreased. Conversely, matrine administration significantly increased the proportion of beneficial bacteria such as Ruminiclostridium_9, Lachnospiraceae_NK4A136_group and Ruminococcaceae_unclassified. In conclusion, amoxicillin administration could change the microbial community composition and structure by increasing the proportion of pathogenic to beneficial bacteria, whereas matrine could increase the number of beneficial bacteria. Moreover, this study provides a theoretical basis for finding alternatives to antibiotics to decrease bacterial resistance and intestinal flora imbalance.

Systematic Review: The Gut Microbiome and Its Potential Clinical Application in Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is a chronic relapsing-remitting systemic disease of the gastrointestinal tract. It is well established that the gut microbiome has a profound impact on IBD pathogenesis. Our aim was to systematically review the literature on the IBD gut microbiome and its usefulness to provide microbiome-based biomarkers. A systematic search of the online bibliographic database PubMed from inception to August 2020 with screening in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines was conducted. One-hundred and forty-four papers were eligible for inclusion. There was a wide heterogeneity in microbiome analysis methods or experimental design. The IBD intestinal microbiome was generally characterized by reduced species richness and diversity, and lower temporal stability, while changes in the gut microbiome seemed to play a pivotal role in determining the onset of IBD. Multiple studies have identified certain microbial taxa that are enriched or depleted in IBD, including bacteria, fungi, viruses, and archaea. The two main features in this sense are the decrease in beneficial bacteria and the increase in pathogenic bacteria. Significant differences were also present between remission and relapse IBD status. Shifts in gut microbial community composition and abundance have proven to be valuable as diagnostic biomarkers. The gut microbiome plays a major role in IBD, yet studies need to go from casualty to causality. Longitudinal designs including newly diagnosed treatment-naïve patients are needed to provide insights into the role of microbes in the onset of intestinal inflammation. A better understanding of the human gut microbiome could provide innovative targets for diagnosis, prognosis, treatment and even cure of this relevant disease.

Barley Leaf Insoluble Dietary Fiber Alleviated Dextran Sulfate Sodium-Induced Mice Colitis by Modulating Gut Microbiota

Supplementation of dietary fiber has been proved to be an effective strategy to prevent and relieve inflammatory bowel disease (IBD) through gut microbiota modulation. However, more attention has been paid to the efficacy of soluble dietary fiber than that of insoluble dietary fiber (IDF). In the present study, we investigated whether IDF from barley leaf (BLIDF) can inhibit gut inflammation via modulating the intestinal microbiota in DSS-induced colitis mice. The mice were fed 1.52% BLIDF-supplemented diet for 28 days. Results demonstrated that feeding BLIDF markedly mitigated DSS-induced acute colitis symptoms and down-regulated IL-6, TNF-α, and IL-1β levels in the colon and serum of colitis mice. BLIDF supplementation effectively reduced the abundance of Akkermansia and increased the abundance of Parasutterella, Erysipelatoclostridium, and Alistipes. Importantly, the anti-colitis effects of BLIDF were abolished when the intestinal microbiota was depleted by antibiotics. Furthermore, the targeted microbiota-derived metabolites analysis suggested that BLIDF feeding can reverse the DSS-induced decline of short-chain fatty acids and secondary bile acids in mice feces. Finally, BLIDF supplementation elevated the expression of occludin and mucin2, and decreased the expression of claudin-1 in colons of DSS-treated mice. Overall, our observations suggest that BLIDF exerts anti-inflammatory effects via modulating the intestinal microbiota composition and increasing the production of microbiota-derived metabolites.

Differential Toxicological Outcome of Corn Oil Exposure in Rats and Mice as Assessed by Microbial Composition, Epithelial Permeability, and Ileal Mucosa-Associated Immune Status

Studies to evaluate the toxicity of xenobiotics on the human gut microbiome and related health effects require a diligent selection of (1) an appropriate animal model to facilitate toxicity assessment in predicting human exposure, and (2) an appropriate non-interfering vehicle for the administration of water insoluble compounds. In biomedical studies with water insoluble xenobiotics, corn oil is one of the most commonly used nonaqueous vehicles. This study evaluated the suitability of corn oil as a vehicle in adult female Sprague Dawley rats and adult CD-1 mice; the rodent models that are often utilized in toxicological studies. We studied the host response in terms of change in the intestinal microbiome and mRNA expression of intestinal permeability and immune response-related genes when water (control) and corn oil (2 ml/kg) were administered as a vehicle through oral gavage. The results showed that the use of corn oil as a vehicle has no adverse impact in rats for either the immune response or the intestinal microbial population. On the other hand, mice treated with corn oil showed changes in bacterial community adhered to the ileum, as well as changes in the mRNA expression of intestinal permeability-related and ileal mucosa-associated immune response genes. Overall, results of this study suggest that the type of rodent species and vehicle used in toxicological risk assessments of xenobiotics studies should be taken into consideration in the experimental setup and study design.