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Lactobacillus spp. can be beneficial for the prevention or treatment of ulcerative colitis (UC). In this study, 153 participants who followed vegan, omnivorous, or high-meat diet were recruited. Compositional analysis of the Lactobacillus community in feces revealed that Lactobacillus fermentum strains were significantly affected by diet. Administration of mixed L. fermentum strains from vegans significantly improved inflammation compared to that from omnivores and high-meat consumers, as evidenced by a significant reduction in colonic tissue damage, improvement in inflammatory cytokines, enhanced expression of ZO-1, occludin, and claudin-3, and a significant increase in short chain fatty acids concentration. The effect of a single strain of L. fermentum was similar to that of a mixed strains of L. fermentum group. Genomic analysis suggested that L. fermentum strains from the guts of vegans possessed a higher prevalence of genes involved in carbohydrate catabolism than those from the guts of omnivores and high-meat eaters. In particular, the ME2 gene is involved in the biosynthesis of acetate, a compound considered to possess anti-inflammatory properties. In conclusion, this study indicates strain-specific differences in the ability of L. fermentum strains to alleviate UC in mice, influenced by habitual diets.

Immune checkpoint blockade (ICB) therapeutics are highly effective in cancer immunotherapy, but gastrointestinal toxicity limited the application. Intestinal microbiota plays a crucial role in ICB-associated colitis. 2’-Fucosyllactose (2’FL) is most abundance prebiotic in human milk that can reshape gut microbiota and exert immune regulatory effect. The study aimed to determine the effects of 2’FL on ICB-associated colitis and to uncover the mediating mechanism. ICB-associated colitis was induced by the ipilimumab and dextran sulfate sodium. Oral administration of 2’FL (0.6 g/(kg’day)) ameliorated ICB-induced colitis by enhancing regulatory T cells (Treg) and the M2/M1 ratio of macrophages in colon. 2’FL treatment also increased the expression of tight junction proteins (zonula occludens-1 (ZO-1) and mucin 2 (MUC2)) and antioxidant stress indicators (superoxide dismutase (SOD) and catalase (CAT)). In addition, administration of 2’FL increased the abundance of Bifidobacterium and Lactobacillus, and elevated the levels of microbial metabolites, such as indole-3-lactic acid (ILA), which activated the aryl hydrocarbon receptor ligands (AHR) pathway. The protective effect of 2’FL was abolished upon depletion of gut microbiota, and ILA treatment partially simulated the protective effect of 2’FL. Notably, 2’FL did not exhibit inhibition of antitumor immunity. These f indings suggest that 2’FL could serve as a potential protective strategy for ICB-associated colitis by modulating the intestinal microbiota and bacterial metabolites.

Inflammatory bowel disease (IBD) is a complex relapsing inflammatory disease in the gut and is driven by complicated host-gut microbiome interactions. Gut commensals have shown different functions in IBD prevention and treatment. To gain a mechanistic understanding of how different commensals affect intestinal inflammation, we compared the protective effects of 6 probiotics (belonging to the genera Akkermansia, Bifidobacterium, Clostridium, and Enterococcus) on dextran sulfate sodium (DSS)-induced colitis in mice with or without gut microbiota. Anti-inflammatory properties (ratio of interleukin (IL)-10 and IL-12) of these strains were also evaluated in an in vitro mesenteric lymph nodes (MLN) co-culture system. Results showed that 4 probiotics (belonging to the species Bifidobacterium breve, Bifidobacterium bifidum, and Enterococcus faecalis) can alleviate colitis in normal mice. The probiotic strains differed in regulating the intestinal microbiota, cytokines (IL-10, IL-1β and interferon (IFN)-γ), and tight junction function (Zonulin-1 and Occludin). By constrast, Akkermansia muciniphila AH39 and Clostridium butyricum FHuNHHMY49T1 were not protective. Interestingly, B. breve JSNJJNM2 with high anti-inflammatory potential in the MLN model could relieve colitis symptoms in antibiotic cocktail (Abx)-treated mice. Meanwhile, E. faecalis FJSWX25M1 induced low levels of cytokines in vitro and showed no beneficial effects. Therefore, we provided insight into the clinical application of probiotics in IBD treatment.

Akkermansia muciniphila play an important in ameliorating obesity but is not allowed for direct consumption in most countries. To date, microbiota-directed foods selectively promote the targeted human gut microbes, providing a strategy for A. muciniphila enhancement. Multiple studies have indicated the potential regulation of the polyphenol on A. muciniphila. Therefore, a polyphenol screening based on A. muciniphila upregulation was performed in mice. Chlorogenic acid (CGA) exhibited a greater response to A. muciniphila upregulation. Furthermore, we found that CGA did not directly promote A. muciniphila growth or mucin secretion. Microbiome and metabolomics revealed that the increased abundance of A. muciniphila resulted from the inhibition of CGA on Desulfovibrio and Alistipes and the influence of docosahexaenoic acid, β-hydroxybutyrate, and N-acetyl-lactosamine. Finally, to confirm the regulation of CGA on A. muciniphila under disease conditions, high-fat diet-fed mice were established. The results showed CGA promoted A. muciniphila growth, and we expectedly found that CGA suppressed the augment in body weight of mice, significantly attenuated adipose tissue abnormality, provided liver protection and improved gut barrier integrity. These results suggest that CGA inhibits the development of obesity. Overall, our results indicate that microbiota-directed food is a promising approach for the treatment of obesity.

Stachyose is a prebiotic that traditionally extracted from plants, such as vegetable. It has been demonstrated to alleviate intestinal inflammation by regulating gut microbiota, but the mechanism has been unclear. This research aims to detect the potential mechanism of stachyose in alleviating the severity of ulcerative colitis (UC). The results indicated that the administration of stachyose could recover the body weight, protect against the colonic tissue damage, reduce the pro-inflammatory cytokines levels, and reverse the histological abnormalities in UC mice. Oral stachyose could restore DSS-induced disturbance in intestinal bacteria. Besides, the metabolome result of serum samples showed that stachyose treatment significantly altered serum metabolites against inflammatory responses in colitis mice. Also, a significant correlation can be found between 23 metabolite biomarkers and 18 differential genera. Our results provided a strong foundation for the future study of the protective role of stachyose in maintaining intestinal homeostasis.

This meta-analysis of randomized controlled trials aimed to evaluate the effects of probiotic supplementation on glucose homeostasis in patients with polycystic ovary syndrome (PCOS). The meta-analysis was performed in accordance with the Cochrane Handbook guidelines and relevant the preferred reporting items for systematic reviews and meta-analyses (PRISMA) statement criteria. Of 825 identified reports, 11 randomized clinical trials were included in the meta-analysis. An analysis of pooled extracted data revealed that supplementation with probiotics significantly decreased fasting blood glucose (FBG, n = 7; standardized mean difference (SMD) = −0.40; 95 % confidence interval (CI): −2.02, −0.02; P = 0.04) and insulin levels (n = 6; SMD = −0.57; 95 % CI: −0.89, −0.25; P = 0.0004) and the homeostatic model assessment of insulin resistance (n = 7; SMD = −0.64; 95 % CI: −0.96, −0.31; P = 0.0001) while increasing the quantitative insulin sensitivity check index (QUICKI, n = 5; SMD = 0.58; 95 % CI: 0.08, 1.09; P = 0.02) in patients with PCOS. The FBG-reducing effect decreased as the baseline body mass index (BMI) and mean age of the participants increased. Indeed, a greater number of bacterial species and a higher bacterial dose were shown to reduce QUICKI effectively. The systematic review indicated that probiotic supplementation may help to control glucose homeostasis in adults with polycystic ovarian syndrome.

Studies have determined the immunomodulatory activities of cell-surface polysaccharides of lactic acid bacteria (LAB) and Bacteroides; however, the mechanisms, synthesis, regulation, structure, and functional links have not been systematically discussed. We first introduce the structure of the capsular polysaccharides (CPSs) of commonly studied probiotics and Bacteroides. Wzx-Wzy dependent and ATP-binding cassette (ABC) transporter-dependent pathways are the two main biosynthesis and secretion of CPS pathways. The genes known to be associated with these two pathways are mainly those associated with priming glycosyltransferase (pGT); a variable number of genes encoding for different glycosyl transferases (GTs); Wzx/Wzy-encoding enzymes related to flippases and polymerases; and ABC-transporter genes. In addition, the effects of CPSs on host immunity as well as their related underlying mechanisms are described. Surface polysaccharides on probiotics can serve as a mask to aid in their escape from attacks from the host’s immune system. In turn, they also exhibit immunomodulatory activities, such as strengthening the functions of macrophages, promoting the maturation of antigen-presenting cells, and inducing regulatory T cells. All of these effects of cell-surface polysaccharides exhibit their significant protective properties in immunocompromised diseases, such as colitis, arthritis, and dermatitis. Finally, we focused on their structure and functional links.

People are increasingly aware of the role of vegetarian diets in modulating human gut microbial abundance and intestinal physiology. A plant-based diet is thought to benefit host health by contributing to establish a diverse and stable microbiome. In addition, microbe-derived metabolites of specific nutrients known to be abundant in vegetarian diets (such as indigestible carbohydrates, arginine, and others) are important to promote effective intestinal immune responses, maintain intestinal barrier function, and protect against pathogens. This review explores the characteristics of the gut microbiome formed by vegetarian diets and the effects of diet-associated nutrients on intestinal microbial abundance. The interactions between the microbe-derived metabolites of vegetarian diet-associated nutrients and intestinal physiology are also discussed.

This study was performed to determine the effects of bacteriocin-producing and non-bacteriocin-producing Pediococcus acidilactici strains on the immune system and intestinal flora of normal mice. Two P. acidilactici strains with antibacterial activity (P. acidilactici CCFM28 and CCFM18) were obtained based on the inhibition-zone assay. The produced components were identified as bacteriocins through protease treatment, pH adjustment and hydrogen peroxide treatment. Bacteriocin-producing and non-bacteriocin-producing P. acidilactici strains (P. acidilactici CCFM28, CCFM18 and NT17-3) caused significant changes in serum immune factors and intestinal flora of normal mice. After 14 days of intervention, the relative abundance of Firmicutes was significantly decreased, but that of Proteobacteria was significantly increased at the phylum level. At the genus level, the administration of three P. acidilactici strains resulted in the downregulation of Blautia and the upregulation of Ruminococcus and Lactobacillus. Furthermore, there were also different regulations on some probiotic strains, such as Bifidobacterium, Coprococcus and Akkermansia, which were closely related to the antibacterial ability of the bacteriocin and the type of strain. The results indicated that the intervention of different P. acidilactici strains could differently change the structure of intestinal flora in normal mice, which provided theoretical guidance for the selective use of bacteriocin-producing strains for health regulation in the future.