Lactobacillus GG-fermented milk prevents DSS-induced colitis and regulates intestinal epithelial homeostasis through activation of epidermal growth factor receptor

Lacticaseibacillus rhamnosus GG alleviates sleep deprivation-induced intestinal barrier dysfunction and neuroinflammation in mice

Consuming probiotic products is a solution that people are willing to choose to augment health. As a global health hazard, sleep deprivation (SD) can cause both physical and mental diseases. The present study investigated the protective effects of Lacticaseibacillus rhamnosus GG (LGG), a widely used probiotic, on a SD mouse model. Here, it has been shown that SD induced intestinal damage in mice, while LGG supplementation attenuated disruption of the intestinal barrier and enhanced the antioxidant capacity. Microbiome analysis revealed that SD caused dysbiosis in the gut microbiota, characterized by increased levels of Clostridium XlVa, Alistipes, and Desulfovibrio, as well as decreased levels of Ruminococcus, which were partially ameliorated by LGG. Moreover, SD resulted in elevated pro-inflammatory cytokine concentrations in both the intestine and the brain, while LGG provided protection in both organs. LGG supplementation significantly improved locomotor activity in SD mice. Although heat-killed LGG showed some protective effects in SD mice, its overall efficacy was inferior to that of live LGG. In terms of mechanism, it was found that AG1478, an inhibitor of the epidermal growth factor receptor (EGFR) tyrosine kinase, could diminish the protective effects of LGG. In conclusion, LGG demonstrated the ability to alleviate SD-induced intestinal barrier dysfunction through EGFR activation and alleviate neuroinflammation.

Molecular Mechanisms of Lacticaseibacillus rhamnosus, LGG® Probiotic Function

To advance probiotic research, a comprehensive understanding of bacterial interactions with human physiology at the molecular and cellular levels is fundamental. Lacticaseibacillus rhamnosus LGG® is a bacterial strain that has long been recognized for its beneficial effects on human health. Probiotic effector molecules derived from LGG®, including secreted proteins, surface-anchored proteins, polysaccharides, and lipoteichoic acids, which interact with host physiological processes have been identified. In vitro and animal studies have revealed that specific LGG® effector molecules stimulate epithelial cell survival, preserve intestinal barrier integrity, reduce oxidative stress, mitigate excessive mucosal inflammation, enhance IgA secretion, and provide long-term protection through epigenetic imprinting. Pili on the cell surface of LGG® promote adhesion to the intestinal mucosa and ensure close contact to host cells. Extracellular vesicles produced by LGG® recapitulate many of these effects through their cargo of effector molecules. Collectively, the effector molecules of LGG® exert a significant influence on both the gut mucosa and immune system, which promotes intestinal homeostasis and immune tolerance.

A key genetic factor governing arabinan utilization in the gut microbiome alleviates constipation

Impaired gastrointestinal motility is associated with gut dysbiosis. Probiotics, such as Bifidobacteria, can improve this bowel disorder; however, efficacy is strain-dependent. We determine that a genetic factor, the abfA cluster governing arabinan utilization, in Bifidobacterium longum impacts treatment efficacy against functional constipation (FC). In mice with FC, B. longum, but not an abfA mutant, improved gastrointestinal transit time, an affect that was dependent upon dietary arabinan. abfA genes were identified in other commensal bacteria, whose effects in ameliorating murine FC were similarly abfA-dependent. In a double-blind, randomized, placebo-controlled clinical trial, supplementation with abfA-cluster-carrying B. longum, but not an abfA-deficient strain, enriched arabinan-utilization residents, increased beneficial metabolites, and improved FC symptoms. Across human cohorts, abfA-cluster abundance can predict FC, and transplantation of abfA cluster-enriched human microbiota to FC-induced germ-free mice improved gut motility. Collectively, these findings demonstrate a role for microbial abfA cluster in ameliorating FC, establishing principles for genomics-directed probiotic therapies.

Recombinant p40 Protein Promotes Expression of Occludin in HaCaT Keratinocytes: A Brief Communication

The ability of epithelial barriers to perform as the first defense line against external damage derives from tight junctions, protein complexes that block microorganisms through the paracellular space. Indeed, disturbances of barrier permeability caused by bacterial metabolites and other inflammatory stimuli are the consequence of changes in protein expression in these complexes. Postbiotics, molecules derived from bacteria with beneficial effects on the host, improve barrier function through the activation of survival pathways in epithelial cells. Lacticaseibacillus rhamnosus GG secretes the muramidase p40, which protects intestinal barriers through an EGFR-dependent pathway. In this work, we cloned, expressed, and purified the recombinant p40 protein from L. rhamnosus GR-1 to evaluate its effect on cell viability, cell cytotoxicity, TEER, and protein levels of tight junctions, as well as EGFR activation via Western blot on HaCaT keratinocytes subjected to LPS. We found a novel mutation at residue 368 that does not change the structure of p40. Our protein also reduces the LPS-induced increase in cell cytotoxicity when it is added prior to this stimulus. Furthermore, although LPS did not cause changes in barrier function, p40 increased TEER and occludin expression in HaCaT, but unlike previous work with p40 from LGG, we found that recombinant p40 did not activate EGFR. This suggests that recombinant p40 enhances epithelial barrier function through distinct signaling pathways.

Lactiplantibacillus plantarum ZJ316-fermented milk ameliorates dextran sulfate sodium-induced chronic colitis by improving the inflammatory response and regulating intestinal microbiota

The pathogenesis of inflammatory bowel disease may be related to local inflammatory damage and disturbances in intestinal microecology. Probiotic therapy is a safe and effective therapeutic approach. Considering that fermented milk is accepted and enjoyed by many people as a daily dietary intervention strategy, its potential to alleviate dextran sulfate sodium (DSS)-induced chronic colitis in mice needs to be explored. In this study, we evaluated the therapeutic effects of Lactiplantibacillus plantarum ZJ316-fermented milk by establishing a mouse model of DSS-induced chronic colitis. The results showed that the disease severity and colonic lesions of inflammatory bowel disease were effectively alleviated by ingestion of fermented milk. At the same time, the expression of proinflammatory cytokines (TNF-α, IL-1β, and IL-6) effectively decreased, and the expression of antiinflammatory cytokines (IL-10) increased. Results based on 16S rRNA gene sequencing indicated that the structure and diversity of intestinal microorganisms changed markedly by intake of L. plantarum ZJ316-fermented milk, and fermented milk reduced the abundance of harmful bacteria (Helicobacter) while promoting the growth of beneficial bacteria (Faecalibacterium, Lactiplantibacillus, and Bifidobacterium). Additionally, the levels of short-chain fatty acids (acetic acid, propionic acid, butyric acid, pentanoic acid, and isobutyric acid) were also increased. In conclusion, the intake of L. plantarum ZJ316-fermented milk can alleviate chronic colitis by suppressing the inflammatory response and regulating intestinal microbiota.

No Associations between Dairy Intake and Markers of Gastrointestinal Inflammation in Healthy Adult Cohort

Dairy products are a good source of essential nutrients and past reviews have shown associations of dairy consumption with decreased systemic inflammation. Links between dairy intake and gastrointestinal (GI) inflammation are under-investigated. Therefore, we examined associations between reported dairy intake and markers of GI inflammation in healthy adults in a cross-sectional observational study, hypothesizing a negative association with yogurt intake, suggesting a protective effect, and no associations with total dairy, fluid milk, and cheese intake. Participants completed 24-h dietary recalls and a food frequency questionnaire (FFQ) to assess recent and habitual intake, respectively. Those who also provided a stool sample (n = 295), and plasma sample (n = 348) were included in analysis. Inflammation markers from stool, including calprotectin, neopterin, and myeloperoxidase, were measured along with LPS-binding protein (LBP) from plasma. Regression models tested associations between dairy intake variables and inflammation markers with covariates: age, sex, and body mass index (BMI). As yogurt is episodically consumed, we examined differences in inflammation levels between consumers (>0 cup equivalents/day reported in recalls) and non-consumers. We found no significant associations between dairy intake and markers of GI inflammation. In this cohort of healthy adults, dairy intake was not associated with GI inflammation.

Prevention of DSS-induced colitis in mice with water kefir microbiota via anti-inflammatory and microbiota-balancing activity

Water kefir, a natural and stable functional microbiota system consisting of a symbiotic mixture of probiotics, shows multiple bioactivities but little is known about the effect of water kefir microbiota on the prevention of inflammatory bowel disease (IBD), which is one of the most common intestinal problems and has become a worldwide public health concern. Here, the main objectives of the present study were to investigate the preventative effects of water kefir microbiota, a probiotic consortium mainly consisting of bacteria belonging to Acetobacter, Lactobacillus, and Komagataeibacter and fungi belonging to Saccharomyces and Talaromyces, in a dextran sodium sulfate (DSS)-induced colitis mouse model and unveil the underlying mechanism of the action. Water kefir microbiota effectively improved the disease severity of DSS-induced colitis, including decreased body weight and colon length, increased spleen index and DAI score, and colonic tissue damage. Moreover, water kefir microbiota restored the abnormal expression of tight junction proteins (such as occludin, ZO-1, and claudin-1) and pro-inflammatory and anti-inflammatory cytokines (such as IL-1β, IL-6, TNF-α, COX-2, iNOS, and IL-10) and inactivated TLR4-MyD88-NF-κB pathway induced by DSS. Water kefir microbiota also improved the composition and metabolism of intestinal microbiota. These findings demonstrated that water kefir microbiota could exert protective roles in the DSS-induced colitis mouse model by reducing inflammation and regulating microbial dysbiosis, which will be helpful for the development of water kefir microbiota-based microbial products as an alternative preventative strategy for IBD.

Intestinal epithelial cell-derived components regulate transcriptome of Lactobacillus rhamnosus GG

Introduction

Intestinal epithelial cells (IECs) provide the frontline responses to the gut microbiota for maintaining intestinal homeostasis. Our previous work revealed that IEC-derived components promote the beneficial effects of a commensal and probiotic bacterium, Lactobacillus rhamnosus GG (LGG). This study aimed to elucidate the regulatory effects of IEC-derived components on LGG at the molecular level.

Methods

Differential gene expression in LGG cultured with IEC-derived components at the timepoint between the exponential and stationary phase was studied by RNA sequencing and functional analysis.

Results

The transcriptomic profile of LGG cultured with IEC-derived components was significantly different from that of control LGG, with 231 genes were significantly upregulated and 235 genes significantly down regulated (FDR <0.05). The Clusters of Orthologous Groups (COGs) and Gene Ontology (GO) analysis demonstrated that the predominant genes enriched by IEC-derived components are involved in nutrient acquisition, including transporters for amino acids, metals, and sugars, biosynthesis of amino acids, and in the biosynthesis of cell membrane and cell wall, including biosynthesis of fatty acid and lipoteichoic acid. In addition, genes associated with cell division and translation are upregulated by IEC-derived components. The outcome of the increased transcription of these genes is supported by the result that IEC-derived components significantly promoted LGG growth. The main repressed genes are associated with the metabolism of amino acids, purines, carbohydrates, glycerophospholipid, and transcription, which may reflect regulation of metabolic mechanisms in response to the availability of nutrients in bacteria.

Discussion

These results provide mechanistic insight into the interactions between the gut microbiota and the host.

Development of a microecologic product from Lactobacillus rhamnosus based on silica

BACKGROUND

Probiotics are primarily made into microecologic products for use in the food and feed industries. The freeze-drying technique is widely used in their preparation to maintain their high level of bioactivity. This causes high costs in terms of the energy and time needed. In this study, we developed a method to produce a highly active microecologic product from Lactobacillus rhamnosus using heating and silica.

RESULTS

A microecologic product was made successfully from L. rhamnosus using the whole bacterial culture broth, without waste, and using food-grade silica (4.5 mL g^-1 ) to absorb water before drying at 37 °C for 8 h. The activity of L. rhamnosus cells was increased significantly by adding water extracts of green tea to the culture medium. The viable amount of L. rhamnosus in the obtained microecologic product was 9.80 × 10¹⁰  cfu g^-1 with a survival rate of 224.67% in simulated gastric juice for 3 h and 68.2% in simulated intestinal juice for 3 h. The microecologic product treated an intestinal infection by multi-drug-resistant Staphylococcus aureus in mice very efficiently.

CONCLUSION

The study developed an economic, eco-friendly, and efficient method for preparing highly active microecologic agents using heating and without waste. © 2022 Society of Chemical Industry.

Role of Intestinal Microbes in Chronic Liver Diseases

With the recent availability and upgrading of many emerging intestinal microbes sequencing technologies, our research on intestinal microbes is changing rapidly. A variety of investigations have found that intestinal microbes are essential for immune system regulation and energy metabolism homeostasis, which impacts many critical organs. The liver is the first organ to be traversed by the intestinal portal vein, and there is a strong bidirectional link between the liver and intestine. Many intestinal factors, such as intestinal microbes, bacterial composition, and intestinal bacterial metabolites, are deeply involved in liver homeostasis. Intestinal microbial dysbiosis and increased intestinal permeability are associated with the pathogenesis of many chronic liver diseases, such as alcoholic fatty liver disease (AFLD), non-alcoholic fatty liver disease (NAFLD), non-alcoholic steatohepatitis (NASH), chronic hepatitis B (CHB), chronic hepatitis C (CHC), autoimmune liver disease (AIH) and the development of hepatocellular carcinoma (HCC). Intestinal permeability and dysbacteriosis often lead to Lipopolysaccharide (LPS) and metabolites entering in serum. Then, Toll-like receptors activation in the liver induces the exposure of the intestine and liver to many small molecules with pro-inflammatory properties. And all of these eventually result in various liver diseases. In this paper, we have discussed the current evidence on the role of various intestinal microbes in different chronic liver diseases. As well as potential new therapeutic approaches are proposed in this review, such as antibiotics, probiotics, and prebiotics, which may have an improvement in liver diseases.

[Bifidobacterium bifidum TMC3115 Promotes Early Life Intestinal Microbiota Building to Alleviate Symptoms of Inflammatory Bowel Disease]

Objective

To investigate the effects of using Bifidobacterium bifidum TMC3115 in early life on intestinal microbiota and immune functions and the long-term impact on inflammatory bowel disease.

Methods

Fourteen pregnant BALB/c mice were purchased and 84 newborn BALB/c mice were subsequently obtained. Then, the newborn mice were randomly assigned to a normal saline (NS) group and a TMC3115 group, given via oral gavage normal saline and TMC3115, respectively, at a daily volume of 0.2 mL for each mouse. About 42 mice were assigned to each group. The gavage was stopped after 3 weeks. At this point, half of the mice in each group were sacrificed, and then the remaining mice in each group were randomly divided into NS-water group, NS-DSS group, TMC3115-water group, and TMC3115-DSS group, with about 10 mice in each group. The mice were given regular feed until the end of week 6 when they were given 3% dextran sulphate sodium (DSS) ad libitum for 4 days to establish the enteritis model, while the non-modeling groups were given pure water ad libitum. The experiment ended after 6 weeks and 4 days. The weekly body mass changes of the mice were documented. The intestinal tissue at the end of the experiment and the fecal samples, spleen and serum of the mice at 3 weeks and at the end of the experiment were collected to determine the pathology scores of colonic inflammation, the composition of fecal gut microbiota, spleen organ index and the mass concentration of serum cytokines.

Results

1) At the end of the experiment, the inflammatory pathology score was significantly lower in the TMC3115-DSS group compared with that of the Saline-DSS group ( P<0.05), with less disruption of colonic crypt structures and other structures, less inflammatory infiltration, and more intact epithelial structures. 2) At 3 weeks, in comparison with those of the NS group, the relative abundance of Bifidobacteriumwas significantly higher in the feces of the TMC3115 ( P<0.05), the relative abundance of both Enterococcusand Staphylococcuswas lower ( P<0.05), the splenic organ index was significantly higher ( P<0.05), and interleukin (IL)-10 was significantly decreased ( P<0.05), while there was no significant change in IL-6 or TNF-α ( P>0.05). At the end of the experiment, in comparison with those of the NS-DSS group that undergone DSS induction, the TMC3115-DSS group had reduced relative abundance of Staphylococcus, Staphylococcus tumefaciens and Escherichia/ Shigellain the feces ( P<0.05), while the splenic organ index was significantly higher ( P<0.05), and there were no significant changes in IL-6 or TNF-α ( P>0.05).

Conclusion

The use of TMC3115 in early life promotes the construction of gut microbiota in neonatal mice, thereby producing a long-term effect that alleviates colitis in mice, but the mechanisms involved are still not fully understood.

Limnospira indica PCC 8005 or Lacticaseibacillus rhamnosus GG Dietary Supplementation Modulate the Gut Microbiome in Mice

While dietary supplements can have beneficial effects on the health of the intestine, these effects can come with unresolved issues in terms of therapeutic efficacy and mechanisms of action. In this study, the model probiotic Lacticaseibacillus rhamnosus GG ATCC 53103 and the anciently used dietary supplement Limnospira indica strain PCC 8005 were compared for their effects on murine intestinal ecology. Healthy male mice received either saline or suspensions of living cells of L. indica PCC 8005 or L. rhamnosus GG daily along a two-week intervention period, followed by a two-week washout period. Both bacteria-based solutions appeared able to transiently shift the microbial community, which were characterized by a higher relative abundance of members of the butyrate producing Lachnospiraceae and Porphyromonadaceae families.

Lactobacillus spp. for Gastrointestinal Health: Current and Future Perspectives

In recent decades, probiotic bacteria have become increasingly popular as a result of mounting scientific evidence to indicate their beneficial role in modulating human health. Although there is strong evidence associating various Lactobacillus probiotics to various health benefits, further research is needed, in particular to determine the various mechanisms by which probiotics may exert these effects and indeed to gauge inter-individual value one can expect from consuming these products. One must take into consideration the differences in individual and combination strains, and conditions which create difficulty in making direct comparisons. The aim of this paper is to review the current understanding of the means by which Lactobacillus species stand to benefit our gastrointestinal health.

Lactobacillus fermentum Stimulates Intestinal Secretion of Immunoglobulin A in an Individual-Specific Manner

Immunoglobulin A (IgA), as the most secreted immunoglobulin in the intestine, plays an irreplaceable role in mucosal immunity regulation. Previous studies have indicated that Lactobacillus showed strain specificity in stimulating the secretion of IgA through intestinal mucosal lymphocytes. The reason for this phenomenon is not clear. The current studies have been aimed at exploring the effect of a strain on the secretion of IgA in the host’s intestine, but the mechanism behind it has not been seriously studied. Based on this, we selected five strains of Lactobacillus fermentum isolated from different individuals to determine whether there are intraspecific differences in stimulating the secretion of IgA from the intestinal mucosa. It was found that IgA concentrations in different intestinal segments and faeces induced by L. fermentum were different. 12-1 and X6L1 strains increased the secretion of IgA by the intestine significantly. In addition, different strains of L. fermentum were also proven to have different effects on the host gut microbiota but no significant effects on IgA-coated microbiota. Besides, it was speculated that different strains of L. fermentum may act on different pathways to stimulate IgA in a non-inflammatory manner. By explaining the differences of IgA secretion in the host’s intestine tract stimulated by different strains of L. fermentum, it is expected to provide a theoretical basis for the stimulation of intestinal secretion of IgA by Lactobacillus and a new direction for exploring the relationship between Lactobacillus and human immunity.

Positive Effects of Neutrophil Elastase Inhibitor (Sivelestat) on Gut Microbiome and Metabolite Profiles of Septic Rats

Background

Neutrophil elastase (NE) is associated with sepsis occurrence and progression. We hypothesized that the NE inhibitor Sivelestat might modulate abnormal gut microbiota and metabolites during sepsis.

Methods

Sixty Sprague-Dawley (SD) rats were randomly divided into sham control (SC), sepsis (CLP), and sepsis+Sivelestat (Sive) groups. The rats’ survival status was monitored for 24 hours postoperatively, and feces were collected for microbiome and non-targeted metabolomics analyses.

Results

Sivelestat administration significantly improved the survival of septic rats (80% vs 50%, P = 0.047). Microbiome analysis showed that the microbiota composition of rats in the CLP group was significantly disturbed, as potential pathogens such as Escherichia-Shigella and Gammaproteobacteria became dominant, and the beneficial microbiota represented by Lactobacillus decreased. These changes were reversed in Sive group, and the overall microbial status was restored to a similar composition to SC group. Differential analysis identified 36 differential operational taxonomic units and 11 metabolites between the Sive and CLP groups, such as 6-Aminopenicillanic acid, gamma-Glutamyl-leucine, and cortisone (variable importance in projection>1and P<0.05). These discriminatory metabolites were highly correlated with each other and mainly involved in the phenylalanine, tyrosine, and tryptophan biosynthesis pathways. Integrated microbiome and metabolome analyses found that almost all Sivelestat-modulated microbes were associated with differential metabolites (P < 0.05), such as Lactobacillus and some amino acids, suggesting that the Sivelestat-induced metabolic profile differences were in part due to its influence on the gut microbiome.

Conclusion

Sivelestat administration in septic rats improved survival, gut microbiota composition and associated metabolites, which could provide new options for sepsis treatment.

Metabolites Produced by a New Lactiplantibacillus plantarum Strain BF1-13 Isolated from Deep Seawater of Izu-Akazawa Protect the Intestinal Epithelial Barrier from the Dysfunction Induced by Hydrogen Peroxide

This study aimed to investigate the protective effect of the metabolites produced by a new Lactiplantibacillus plantarum strain BF1-13, isolated from deep seawater (DSW), on the intestinal epithelial barrier against the dysfunction induced by hydrogen peroxide (H2O2) and to elucidate the mechanism underlying the effect. Protective effect of the metabolites by strain BF1-13 on the barrier function of the intestinal epithelial model treated with H2O2 was investigated by the transepithelial electrical resistance (TEER). The metabolites enhanced the Claudin-4 (CLDN-4) expression, including at the transcription level, indicated by immunofluorescence staining and quantitative RT-PCR. The metabolites also showed a suppression of aquaporin3 (AQP3) expression. Lactic acid (LA) produced by this strain of homofermentative lactic acid bacteria (LAB) had a similar enhancement on CLDN-4 expression. The metabolites of L. plantarum strain BF1-13 alleviated the dysfunction of intestinal epithelial barrier owing to its enhancement on the tight junctions (TJs) by LA, along with its suppression on AQP3-facilitating H2O2 intracellular invasion into Caco-2 cells. This is the first report on the enhancement of TJs by LA produced by LAB.

Lactobacillus rhamnosus GG colonization in early life regulates gut-brain axis and relieves anxiety-like behavior in adulthood

Evidence reveals that gut dysbiosis is involved in bidirectional interactions in gut-brain axis and participates in the progress of multiple disorders like anxiety. Gut microbes in early life are crucial for establishment of host health. We aimed to investigate whether early life probiotics Lactobacillus rhamnosus GG (LGG) colonization could relieve anxiety in adulthood through regulation of gut-brain axis. Live or fixed LGG was gavaged to C57BL/6 female mice from day 18 of pregnancy until natural birth, and newborn mice from day 1 to day 5 respectively. In this study, we found that live LGG could be effectively colonized in the intestine of offspring. LGG colonization increased intestinal villus length and colonic crypt depth, accompanied with barrier function protection before weaning. Microbiota composition by 16S rRNA sequencing showed that some beneficial bacteria, such as Akkermansia and Bifidobacteria, were abundant in LGG colonization group. The protective effect of LGG on gut microbiota persisted from weaning to adulthood. Intriguingly, behavioral results assessed by elevated plus mazed test and open field test demonstrated relief of anxiety-like behavior in adult LGG-colonized offspring. Mechanically, LGG colonization activated epithelial growth factor receptor (EGFR) and enhanced serotonin transporter (SERT) expression and modulated serotonergic system in the intestine, and increased brain-derived neurotrophic factor and γ-aminobutyric acid receptor levels in the hippocampus and amygdala. Blocking EGFR blunted LGG-induced the increased SERT and zonula occludens-1 expression. Collectively, early life LGG colonization could protect intestinal barrier of offspring and modulate gut-brain axis in association with relief of anxiety-like behavior in adulthood.

Probiotics and gut microbiota: mechanistic insights into gut immune homeostasis through TLR pathway regulation

Consumption of probiotics as a useful functional food improves the host's wellbeing, and, when paired with prebiotics (indigestible dietary fibre/carbohydrate), often benefits the host through anaerobic fermentation.

Lactobacillus casei ATCC 393 and it's metabolites alleviate dextran sulphate sodium-induced ulcerative colitis in mice through the NLRP3-(Caspase-1)/IL-1β pathway

Inflammatory bowel disease (IBD) represents a broad group of intestinal disorders, including ulcerative colitis (UC) and Crohn's disease (CD). Probiotics are increasingly being recognized as a means of treatment for people suffering from IBD. Our previous studies demonstrated that Lactobacillus casei ATCC 393 (L. casei ATCC 393) effectively alleviated enterotoxigenic Escherichia coli K88-induced intestinal barrier dysfunction. This study was conducted to investigate the protective effects of L. casei ATCC 393 and its metabolites on dextran sulfate sodium (DSS)-induced UC in C57BL/6 mice and the potential mechanism of these effects. The results showed that oral administration of L. casei ATCC 393 and its metabolites both effectively reversed the DSS-induced weight loss, and the reduction in the disease activity index (DAI), colon length, and villus height of colon tissue in mice. Compared to the DSS-induced model group, L. casei ATCC 393 and its metabolites significantly inhibited the infiltration of immune cells into the intestinal mucosa, decreased the production of pro-inflammatory factors, and increased the expression of anti-inflammatory factors in the serum and colon tissue, increased the expression levels of occludin, ZO-1, and claudin-1, and reduced the expression of nucleotide binding oligomeric domain-like receptor protein 3 (NLRP3), cysteine proteinase-1 (Caspase-1), IL-1β, and IL-18. In addition, L. casei ATCC 393 and its metabolites effectively improved DSS-induced gut microbiota dysbiosis. These results suggested that L. casei ATCC 393 and its metabolites alleviated the DSS-induced ulcerative inflammatory response in C57BL/6 mice through the NLRP3-(Caspase-1)/IL-1β signaling pathway.

The Effect of Lactobacillus casei on Experimental Porcine Inflammatory Bowel Disease Induced by Dextran Sodium Sulphate

BACKGROUND

Gastrointestinal injury caused by dextran sodium sulphate (DSS) is a reliable porcine experimental model of inflammatory bowel disease (IBD). The purpose of this study was to evaluate the effect of probiotic Lactobacillus casei DN 114001 (LC) on DSS-induced experimental IBD.

RESULTS

Eighteen female pigs (Sus scrofa f. domestica, weight 33-36 kg, age 4-5 months) were divided into 3 groups (6 animals per group): controls with no treatment, DSS, and DSS + LC. LC was administered to overnight fasting animals in a dietary bolus in the morning on days 1-7 (4.5 × 1010 live bacteria/day). DSS was applied simultaneously on days 3-7 (0.25 g/kg/day). On day 8, the pigs were sacrificed. Histopathological score and length of crypts/glands (stomach, jejunum, ileum, transverse colon), length and width of villi (jejunum, ileum), and mitotic and apoptotic indices (jejunum, ileum, transverse colon) were assessed. DSS increased the length of glands in the stomach, length of crypts and villi in the jejunum and ileum, and the histopathological score of gastrointestinal damage, length of crypts and mitotic activity in the transverse colon. Other changes did not achieve any statistical significance. Administration of LC reduced the length of villi in the jejunum and ileum to control levels and decreased the length of crypts in the jejunum.

CONCLUSIONS

Treatment with a probiotic strain of LC significantly accelerated regeneration of the small intestine in a DSS-induced experimental porcine model of IBD.

The ameliorative effect of Lactobacillus plantarum-12 on DSS-induced murine colitis

Some strains of lactobacilli can exert beneficial effects on a host when ingested in an adequate dose, such as immunoregulation and anti-inflammatory activities. In this study, the survival abilities under simulated gastrointestinal conditions, adhesion abilities on HT-29 cell monolayers, and hemolytic activities of four Lactobacillus plantarum strains were assessed. Among the four strains, L. plantarum-12 showed the higher survival rate under simulated gastrointestinal conditions and adhesion index on the HT-29 cell monolayers, exhibited γ-haemolytic activity and had no biological amine producing ability. L. plantarum-12 was administered to dextran sodium sulfate (DSS)-induced ulcerative colitis (UC) Balb/c mice by oral gavage for 10 days. It was observed that the UC Balb/c mice showed symptoms of colonic atrophy, intestinal histopathological change, gut microbial disturbance, and pro-inflammatory cytokine expression. L. plantarum-12 administration remarkably attenuated DSS-induced UC in mice. L. plantarum-12 administration could restore gut microbiota by increasing beneficial bacteria such as Lactobacillus and decreasing intestinal pathogenic bacteria like Proteobacteria. L. plantarum-12 administration could improve immunity via activating the janus kinase-signal transducer and the activator of the transcription (JAK-STAT) pathway and up-regulating adenosine deaminase (ADA) and interferon-induced protein with tetratricopeptide repeats 1 protein (IFIT1), and enforce the intestinal barrier function by up-regulating mucin 2 (MUC2) protein expression. In conclusion, L. plantarum-12 could attenuate DSS-induced UC in Balb/c mice by ameliorating intestinal inflammation, and restoring the disturbed gut microbiota. L. plantarum-12 could be used as promising probiotics to ameliorate colitis.

Antioxidant and Anti-Inflammatory Properties of Probiotic Candidate Strains Isolated during Fermentation of Agave (Agave angustifolia Haw)

Agave species are a source of diverse products for human use, such as food, fiber, and beverages, which include mezcal, a distilled beverage produced by spontaneous fermentation. Agave is an excellent source of high amounts of sugars, minerals, and phenolic compounds, which favor the growth of lactic acid bacteria (LAB) and yeast communities. In this work, 20 promising LAB strains with probiotic characteristics were isolated from the agave fermentation stage in mezcal production. The strains belonged to Lactobacillus plantarum (15), Lactobacillus rhamnosus (2), Enterococcus faecium (2), and Lactococcus lactis (1). These isolates were characterized for their resistance under gastrointestinal conditions, such as lysozyme, acid pH, and bile salts. In addition, the adherence of these LABs to human intestinal epithelial cells (Caco-2 and HT-29 cells) was tested in vitro and their antioxidant and immunomodulatory profile was determined using cellular models. Lactobacillus rhamnosus LM07 and Lactobacillus plantarum LM17 and LM19 strains were selected for their antioxidant properties, and their capacities in an oxidative stress model in intestinal epithelial cells IECs (Caco-2 and HT-29 cells) in the presence of hydrogen peroxide were evaluated. Interestingly, Lactobacillus rhamnosus LM07 and Lactobacillus plantarum LM17 and LM19 strains showed anti-inflammatory properties in TNF-α-stimulated HT-29 cells. Subsequently, bacterial strains exhibiting antioxidant and anti-inflammatory properties were tested in vivo in a mouse model with dinitrobenzene sulfonic acid (DNBS)-induced chronic colitis. Weight loss, intestinal permeability, and cytokine profiles were measured in mice as indicators of inflammation. One of the selected strains, Lactobacillus plantarum LM17, improved the health of the mice, as observed by reduced weight loss, and significantly decreased intestinal permeability. Altogether, our results demonstrate the potential of LAB (and lactobacilli in particular) isolated from the agave fermentation stage in mezcal production. Lactobacillus rhamnosus LM07 and Lactobacillus plantarum LM17 strains represent potential candidates for developing new probiotic supplements to treat inflammatory bowel disease (IBD).

Probiogenomics of Lactobacillus delbrueckii subsp. lactis CIDCA 133: In Silico, In Vitro, and In Vivo Approaches

Lactobacillus delbrueckii subsp. lactis CIDCA 133 (CIDCA 133) has been reported as a potential probiotic strain, presenting immunomodulatory properties. This study investigated the possible genes and molecular mechanism involved with a probiotic profile of CIDCA 133 through a genomic approach associated with in vitro and in vivo analysis. Genomic analysis corroborates the species identification carried out by the classical microbiological method. Phenotypic assays demonstrated that the CIDCA 133 strain could survive acidic, osmotic, and thermic stresses. In addition, this strain shows antibacterial activity against Salmonella Typhimurium and presents immunostimulatory properties capable of upregulating anti-inflammatory cytokines Il10 and Tgfb1 gene expression through inhibition of Nfkb1 gene expression. These reported effects can be associated with secreted, membrane/exposed to the surface and cytoplasmic proteins, and bacteriocins-encoding genes predicted in silico. Furthermore, our results showed the genes and the possible mechanisms used by CIDCA 133 to produce their beneficial host effects and highlight its use as a probiotic microorganism.

Oral Administration of Flavonifractor plautii, a Bacteria Increased With Green Tea Consumption, Promotes Recovery From Acute Colitis in Mice via Suppression of IL-17

Flavonifractor plautii (FP) has been reported to participate in the metabolism of catechins in the human gut. However, there is limited information on the immune regulatory effects of this bacterium. We confirmed that the administration of green tea increases the abundance of FP in the gut microbiota and investigated the effect of FP in a mouse colitis model. Mice were orally administered FP for 10 consecutive days; colonic inflammation was evaluated daily on the basis of stool consistency, gross rectal bleeding, and body weight. In the dextran sodium sulfate model, FP-exposed animals exhibited lower levels of inflammation and strong inhibition of interleukin (IL)-17 signaling. Moreover, lipoteichoic acid from FP was identified as the active component mediating IL-17 suppression. Thus, oral administration of FP appears to modulate gut inflammation and represents a viable and inexpensive oral microbial therapeutic.

Physiological Characteristics of Lactobacillus casei Strains and Their Alleviation Effects against Inflammatory Bowel Disease

Lactobacillus casei, one of the most widely used probiotics, has been reported to alleviate multiple diseases. However, the effects of this species on intestinal diseases are strain-specific. Here, we aimed to screen L. casei strains with inflammatory bowel disease (IBD)-alleviating effects based on in vitro physiological characteristics. Therefore, the physiological characteristics of 29 L. casei strains were determined, including gastrointestinal transit tolerance, oligosaccharide fermentation, HT-29 cell adhesion, generation time, exopolysaccharide production, acetic acid production, and conjugated linoleic acid synthesis. The effects of five candidate strains on mice with induced colitis were also evaluated. The results showed that among all tested L. casei strains, only Lactobacillus casei M2S01 effectively relieved colitis. This strain recovered body weight, restored disease activity index score, and promoted anti-inflammatory cytokine expression. Gut microbiota sequencing showed that L. casei M2S01 restored a healthy gut microbiome composition. The western blotting showed that the alleviating effects of L. casei M2S01 on IBD were related to the inhibition of the NF-κB pathway. A good gastrointestinal tolerance ability may be one of the prerequisites for the IBDalleviating effects of L. casei. Our results verified the efficacy of L. casei in alleviating IBD and lay the foundation for the rapid screening of L. casei strain with IBD-alleviating effects.

Regulatory Effect of Lactobacillus brevis Bmb6 on Gut Barrier Functions in Experimental Colitis

The integrity of gut barrier functions is closely associated with the pathogenesis of colitis. It is speculated that Lactobacillus brevis Bmb6 alleviates colitis by improving the tight junction (TJ) of the inflamed intestinal epithelial layer. In the present study, the regulatory effects of L. brevis Bmb6 on the TJ barrier to ameliorate colitis-symptoms were investigated. Preliminary screening showed that L. brevis Bmb6 exhibited strong acid and bile acid tolerance, along with antioxidants and β-galactosidase activities. In a 14-day dextran sulfate sodium (DSS)-induced colitis mouse model, treatment with L. brevis Bmb6 significantly decreased in the disease activity index score. In addition, histological analyses showed that treatment with L. brevis Bmb6 protected the structural integrity of the intestinal epithelial layer and mucin-secreting goblet cells from DSS-induced damage, with only slight infiltration of immune cells. Interestingly, western blotting analyses showed that the expression of the TJ protein, zona occluden-1, was restored in Bmb6-treated mice, but not in DSS-induced mice. Consistently, the gene expression of inflammatory cytokines (tumor necrosis factor-α and interferon-γ) was also suppressed in the Bmb6-treated mice. Hence, our findings suggest that suppression of inflammatory conditions enhanced expression of TJ protein, ZO-1, or vice versa, contributing to a colitis-ameliorating effect in L. brevis Bmb6.

Molecular mechanisms of postbiotics in colorectal cancer prevention and treatment

The occurrence of colorectal cancer (CRC) has been rising expeditiously and anticipated that 2.4 million new occasions of CRC will be detected yearly around the world until the year 2035. Due to some side-effects and complications of conventional CRC therapies, bioactive components such as microbial-derived biomolecules (postbiotics) have been attaining great significance by researchers for adjuvant therapy in CRC patients. The term 'postbiotics' encompasses an extensive range of complex micro- and macro-molecules (<50, 50-100, and 100< kDa) such as inactivated microbial cells, cell fractions or metabolites, which confer various physiological health benefits to the host when administered in adequate amounts. Postbiotics modulate the composition of the gut microbiota and the functionality of the immune system, as well as promote the CRC treatment effectiveness and reduces its side-effects in CRC patients due to possessing anti-oxidant, anti-proliferative, anti-inflammatory, and anti-cancer activities. Presently scientific literature confirms that postbiotics with their unique characteristics in terms of clinical (safe origin), technological (stability), and economic (low production costs) aspects can be used as promising tools for both prevent and adjuvant treat strategies in CRC patients without any serious undesirable side-effects. This review provides an overview of the concept and safety issues regarding postbiotics, with emphasis on their biological role in the prevention and treatment of CRC.

The Skin and Intestinal Microbiota and Their Specific Innate Immune Systems

The skin and intestine are active organs of the immune system that are constantly exposed to the outside environment. They support diverse microbiota, both commensal and pathogenic, which encompass bacteria, viruses, fungi, and parasites. The skin and intestine must maintain homeostasis with the diversity of commensal organisms present on epithelial surfaces. Here we review the current literature pertaining to epithelial barrier formation, microbial composition, and the complex regulatory mechanisms governing the interaction between the innate immune system and microbiota in the skin and intestine. We also compare and contrast the skin and intestine—two different organ systems responsible creating a protective barrier against the external environment, each of which has unique mechanisms for interaction with commensal populations and host repair.

Effect of dietary probiotics on colon length in an inflammatory bowel disease-induced murine model: A meta-analysis

We investigated the effect of probiotic supplementation on inflammatory bowel disease (IBD) by meta-analysis. We included 30 studies to assess the effect of probiotic administration. We estimated the effect size using standardized mean difference, and we evaluated the statistical heterogeneity of the effect size using Cochran's Q test, followed by meta-ANOVA and meta-regression analysis to explain the heterogeneity of the effect size using a mixed-effects model. We conducted Egger's linear regression test to evaluate publication bias. Among the factors evaluated, colon length and myeloperoxidase showed the greatest Q statistic and I² index, respectively. Colon length, transforming growth factor-β, IL-10, superoxide dismutase, and glutathione showed positive effect sizes in the fixed- and random-effects models. The others (spleen weight, tumor necrosis factor α, IL-1β, IL-6, IL-12, IL-17, IFN-γ, disease activity index, thiobarbituric acid reactive substances, nitric oxide, myeloperoxidase, malondialdehyde, histological score, and macroscopic inflammatory score) showed negative effect sizes in the fixed- and random-effects models. Probiotics showed a significant effect on all investigated factors, except IL-10. In meta-ANOVA and meta-regression analysis, Lactobacillus paracasei was the most effective probiotic for colon length. Lactobacillus paracasei, Lactobacillus reuteri, Lactobacillus fermentum, and a mixture of Lactobacillus bulgaricus and Saccharomyces boulardii (LC + SB) were effective for colon length, tumor necrosis factor α, IL-6, IL-10, IFN-γ, and disease activity index. Lactobacillus rhamnosus was most effective for IL-10 and IFN-γ. Dietary probiotics are effective in improving the symptoms of IBD. Although the results of this meta-analysis had some limitations due to a lack of animal experiments, they will be meaningful to people with IBD.

Probiotics for Alleviating Alcoholic Liver Injury

Many animal experiments and clinical trials showed that probiotics are effective for the treatment of alcoholic liver disease. Alcohol disrupts the composition of intestinal flora; probiotics modulate the gut microbiota and reverse alcohol-associated intestinal barrier dysfunction by decreasing intestinal mucosal permeability and preventing intestinal bacteria from translocating. Probiotics enhance immune responses and reduce the levels of alcohol-induced inflammatory cytokines and reactive oxygen species (ROS) production in the liver and intestine. Probiotics also increase fatty acid β-oxidation and reduce lipogenesis, combating alcohol-induced hepatic steatosis. In this review, we summarize the current knowledge regarding the mechanism of action of probiotics for reducing the effects of alcoholic liver disease.

Thirty Years of Lactobacillus rhamnosus GG: A Review

Lactobacillus rhamnosus GG (LGG) was the first strain belonging to the genus Lactobacillus to be patented in 1989 thanks to its ability to survive and to proliferate at gastric acid pH and in medium containing bile, and to adhere to enterocytes. Furthermore LGG is able to produces both a biofilm that can mechanically protect the mucosa, and different soluble factors beneficial to the gut by enhancing intestinal crypt survival, diminishing apoptosis of the intestinal epithelium, and preserving cytoskeletal integrity. Moreover LGG thanks to its lectin-like protein 1 and 2 inhibits some pathogens such as Salmonella species. Finally LGG is able to promote type 1 immune-responsiveness by reducing the expression of several activation and inflammation markers on monocytes and by increasing the production of interleukin-10, interleukin-12 and tumor necrosis factor-α in macrophages. A large number of research data on Lactobacillus GG is the basis for the use of this probiotic for human health. In this review we have considered predominantly randomized controlled trials, meta-analysis, Cochrane Review, guide lines of Scientific Societies and anyway studies whose results were evaluated by means of relative risk, odds ratio, weighted mean difference 95% confidence interval. The effectiveness of LGG in gastrointestinal infections and diarrhea, antibiotic and Clostridium difficile associated diarrhea, irritable bowel syndrome, inflammatory bowel disease, respiratory tract infections, allergy, cardiovascular diseases, nonalcoholic fatty liver disease, nonalcoholic steatohepatitis, cystic fibrosis, cancer, elderly end sport were analyzed.

Antioxidant Activity of Yogurt Fermented at Low Temperature and Its Anti-inflammatory Effect on DSS-induced Colitis in Mice

This study was performed to evaluate the antioxidant activity of yogurt fermented at low temperature and the anti-inflammatory effect it has on induced colitis with 2.5% dextran sodium sulfate (DSS) in Balb/c mice. Yogurt premix were fermented with a commercial starter culture containing Lactobacillus acidophilus, Bifidobacterium lactis, Streptococcus thermophilus, and Lactobacillus delbrueckii subsp. bulgaricus at different temperatures: 22°C (low fermentation temperature) for 27 h and 37°C (general fermentation temperature) for 12 h. To measure antioxidant activity of yogurt samples, DPPH, ABTS⁺ and ferric reducing antioxidant potential (FRAP) assays were conducted. For animal experiments, inflammation was induced with 2.5% DSS in Balb/c mice. Yogurt fermented at low temperature showed higher antioxidant activity than that of the yogurt fermented at general temperature. In the inflammatory study, IL-6 (interleukin 6) was decreased and IL-4 and IL-10 increased significantly in DSS group with yogurt fermented at general temperature (DYG) and that with yogurt fermented at low temperature (DYL) compared to that in DSS-induced colitic mice (DC), especially DYL had higher concentration of cytokines IL-4, and IL-10 than DYG. MPO (myeloperoxidase) tended to decrease more in treatments with yogurt than DC. Additionally, yogurt fermented at low temperature had anti-inflammatory activity, although there was no significant difference with general temperature-fermented yogurt (p>0.05).

Mucosal adhesion and anti-inflammatory effects of Lactobacillus rhamnosus GG in the human colonic mucosa: A proof-of-concept study

AIM

To investigate the adhesion and anti-inflammatory effects of Lactobacillus rhamnosus GG (LGG) in the colonic mucosa of healthy and ulcerative colitis (UC) patients, both in vivo and ex vivo in an organ culture model.

METHODS

For the ex vivo experiment, a total of 98 patients (68 UC patients and 30 normal subjects) were included. Endoscopic biopsies were collected and incubated with and without LGG or LGG-conditioned media to evaluate the mucosal adhesion and anti-inflammatory effects [reduction of tumor necrosis factor alpha (TNFα) and interleukin (IL)-17 expression] of the bacteria, and extraction of DNA and RNA for quantification by real-time (RT)-PCR occurred after the incubation. A dose-response study was performed by incubating biopsies at “regular”, double and 5 times higher doses of LGG. For the in vivo experiment, a total of 42 patients (20 UC patients and 22 normal controls) were included. Biopsies were taken from the colons of normal subjects who consumed a commercial formulation of LGG for 7 d prior to the colonoscopy, and the adhesion of the bacteria to the colonic mucosa was evaluated by RT-PCR and compared with that of control biopsies from patients who did not consume the formulation. LGG adhesion and TNFα and IL-17 expression were compared between UC patients who consumed a regular or double dose of LGG supplementation prior to colonoscopy.

RESULTS

In the ex vivo experiment, LGG showed consistent adhesion to the distal and proximal colon in normal subjects and UC patients, with a trend towards higher concentrations in the distal colon, and in UC patients, adhesion was similar in biopsies with active and quiescent inflammation. In addition, bioptic samples from UC patients incubated with LGG conditioned media (CM) showed reduced expression of TNFα and IL-17 compared with the corresponding expression in controls (P < 0.05). Incubation with a double dose of LGG increased mucosal adhesion and the anti-inflammatory effects (P < 0.05). In the in vivo experiment, LGG was detectable only in the colon of patients who consumed the LGG formulation, and bowel cleansing did not affect LGG adhesion. UC patients who consumed the double LGG dose had increased mucosal concentrations of the bacteria and reduced TNFα and IL-17 expression compared with patients who consumed the regular dose (48% and 40% reduction, respectively, P < 0.05).

CONCLUSION

In an ex vivo organ culture model, LGG showed consistent adhesion and anti-inflammatory effects. Colonization by LGG after consumption for a week was demonstrated in vivo in the human colon. Increasing the administered dose increased the adhesion and effectiveness of the bacteria. For the first time, we demonstrated that LGG effectively adheres to the colonic mucosa and exerts anti-inflammatory effects, both ex vivo and in vivo.

Lactobacillus reuteri F-9-35 Prevents DSS-Induced Colitis by Inhibiting Proinflammatory Gene Expression and Restoring the Gut Microbiota in Mice

Probiotics are considered to be a potential treatment for ulcerative colitis (UC). The aim of this study was to compare the preventive effect of a space flight-induced mutant L. reuteri F-9-35 and its wild type on UC in vivo. Female mice were randomly assigned to five groups: one normal and four colitic. Mice from colitis groups were daily gavaged with 0.2 mL 12% (w/v) skim milk containing the mutant or wild type (1 × 10¹¹ CFU/mL), skim milk alone or distilled water for the whole experiment period, starting 7 days before colitis induction. UC was induced by administrating mice with 3.5% (w/v) dextran sulfate sodium (DSS) in drinking water for 7 days, after which DSS was removed and maintained for 3 days as a recovery phase. The results showed that the mice fed with L. reuteri F-9-35 had less inflammatory phenotype according to macroscopic and histological analysis, reduced myeloperoxidase activity, and lower expression of proinflammatory genes (Tumor necrosis factor-α, cyclooxygenase-2 and interleukin-6) in colonic tissue compared with control. Furthermore, L. reuteri F-9-35 protected the mice from gut microbiota dysbiosis from DDS induced colitis. Neither wild type nor the milk alone had such beneficial effects. From above we conclude that L. reuteri F-9-35 has great potential in the prevention of UC as a dietary supplement.

PRACTICAL APPLICATION

Ulcerative colitis (UC) is the most common inflammatory bowel diseases and there is still a lack of safe and effective treatments. Consumption of L. reuteri F-9-35 may effective in preventing human UC.

Supplementation of p40, a Lactobacillus rhamnosus GG-derived protein, in early life promotes epidermal growth factor receptor-dependent intestinal development and long-term health outcomes

The beneficial effects of the gut microbiota on growth in early life are well known. However, knowledge about the mechanisms underlying regulating intestinal development by the microbiota is limited. p40, a Lactobacillus rhamnosus GG-derived protein, transactivates epidermal growth factor receptor (EGFR) in intestinal epithelial cells for protecting the intestinal epithelium against injury and inflammation. Here, we developed p40-containing pectin/zein hydrogels for targeted delivery of p40 to the small intestine and the colon. Treatment with p40-containing hydrogels from postnatal day 2 to 21 significantly enhanced bodyweight gain prior to weaning and functional maturation of the intestine, including intestinal epithelial cell proliferation, differentiation, and tight junction formation, and IgA production in early life in wild-type mice. These p40-induced effects were abolished in mice with specific deletion of EGFR in intestinal epithelial cells, suggesting that transactivation of EGFR in intestinal epithelial cells may mediate p40-regulated intestinal development. Furthermore, neonatal p40 treatment reduced the susceptibility to intestinal injury and colitis and promoted protective immune responses, including IgA production and differentiation of regulatory T cells, in adult mice. These findings reveal novel roles of neonatal supplementation of probiotic-derived factors in promoting EGFR-mediated maturation of intestinal functions and innate immunity, which likely promote long-term beneficial outcomes.

Effect of Milk Fermented with Lactobacillus fermentum on the Inflammatory Response in Mice

Currently, the effect of fermented milk on the T-helper 17 response in inflammatory bowel diseases (IBDs) is unknown. The aim of the present study was to evaluate the effect of milks fermented with Lactobacillus fermentum on the Th1/Th17 response in a murine model of mild IBD. Exopolysaccharide (EPS), lactic acid (LA), and total protein (TP) contents and bacterial concentration were determined. Male C57Bl/6 mice intragastrically received either raw (FM) or pasteurized (PFM) fermented milk before and during a dextran sulfate infusion protocol. Blood, spleen, and colon samples were collected at Weeks 6 and 10. IL-6, IL-10, and TNFα were determined in serum, and IL-17, IL-23, and IFNγ were determined in intestinal mucosa and serum. The FM groups did not differ in cell concentration, LA, or TP content (p > 0.05); FM-J28 had the highest EPS content. Spleen weight and colon length did not differ among the FM groups (p > 0.05). In the FM-J20 and PFM-J20 groups, IL-17 and IFNγ decreased, and the IL-10 concentration was enhanced (p < 0.05) at Week 6. IL-6, TNFα, IL-23, and IFNγ did not differ in serum and mucosa (p > 0.05), and IL-17 was lowest in FM-J28 and FM-J20. Therefore, FM appears to potentially play a role in decreasing the Th17 response. However, further studies are needed to elucidate the FM-mediated anti-inflammatory mechanisms in IBD.

Roles and applications of probiotic Lactobacillus strains

Lactobacilli are recognized as probiotics on account of their health-promoting effects in the host. The aim of this review is to summarize current knowledge of the mechanisms of the adaption factors and main functions of lactobacilli that exert health-promoting effects in the host and to discuss important applications in animal and human health. The adaption mechanisms of lactobacilli facilitate interactions with the host and directly contribute to the beneficial nutritional, physiological, microbiological, and immunological effects in the host. Besides, the application of probiotic lactobacilli will increase our understanding of practical uses based on the roles of these organisms in immunoregulation, antipathogenic activities, and enhancement of the epithelial barrier.

In Vitro Transcriptome Response to a Mixture of Lactobacilli Strains in Intestinal Porcine Epithelial Cell Line

Background: Food and feed supplements containing microorganisms with probiotic potential are of increasing interest due to their healthy promoting effect on human and animals. Their mechanism of action is still unknown. Using a microarray approach, the aim of this study was to investigate the differences in genome-wide gene expression induced by a mixture of three Lactobacillus strains (L. rhamnosus, L. plantarum, and L. paracasei) in intestinal porcine epithelial cells (IPEC-1) and to identify the genes and pathways involved in intestinal barrier functions. Methods: Undifferentiated IPEC-1 cells seeded at a density of 2.0 × 10⁵/mL in 24-wells culture plates were cultivated at 37 °C and 5% CO₂ until they reached confluence (2–3 days). Confluent cells monolayer were then cultivated with 1 mL of fresh lactobacilli (LB) mixture suspension prepared for a concentration of approximately 3.3 × 10⁷ CFU/mL for each strain (1 × 10⁸ CFU/mL in total) for 3 h and analyzed by microarray using Gene Spring GX v.11.5. Results: The functional analysis showed that 1811 of the genes modulated by LB treatment are involved in signaling (95% up-regulation, 121 genes with a fold change higher than 10). The most enhanced expression was registered for AXIN2 (axis inhibition protein 2-AXIN2) gene (13.93 Fc, p = 0.043), a negative regulator of β-catenin with a key role in human cancer. LB affected the cellular proliferation by increasing 10 times (Fc) the NF1 gene encoding for the neurofibromin protein, a tumor suppressor that prevent cells from uncontrolled proliferation. The induction of genes like serpin peptidase inhibitor, clade A member 3 (SERPINA 3), interleukin-20 (IL-20), oncostatin M(OSM), granulocyte-macrophage colony-stimulating factor (GM-CSF), and the suppression of chemokine (C-X-C motif) ligand 2/macrophage inflammatory protein 2-alpha (CXCL-2/MIP-2), regulator of G-protein signaling 2 (RGS2), and of pro-inflammatory interleukin-18 (IL-18) genes highlights the protective role of lactobacilli in epithelial barrier function against inflammation and in the activation of immune response. Conclusion: Gene overexpression was the predominant effect produced by lactobacilli treatment in IPEC-1 cells, genes related to signaling pathways being the most affected. The protective role of lactobacilli in epithelial barrier function against inflammation and in the activation of immune response was also noticed.

Vancomycin and ceftriaxone can damage intestinal microbiota and affect the development of the intestinal tract and immune system to different degrees in neonatal mice

This study aimed to determine how antibiotic-driven intestinal dysbiosis impairs the development and differentiation of the digestive tract and immune organs of host animals. BALB/C neonatal mice were orally administered ceftriaxone or vancomycin from postnatal day 1 to day 21 and sacrificed on day 21. The diversity and abundance of the intestinal bacteria, morphological changes and barrier function of intestinal tract, and the splenic CD4+CD25+Foxp3+ T cells were investigated. The gut microbiota and intestinal tissue were damaged, and the numbers of Ki67-, Muc2- and ZO-1-positive cells were significantly decreased in the antibiotic treatment groups. Furthermore, the administration of ceftriaxone, but not vancomycin, led to a significant reduction in the abundance of splenic CD4+CD25+Foxp3+ T cells. Each antibiotic caused intestinal dysbiosis and characteristically influenced the regeneration of intestinal epithelial cells, formation of the intestinal mucus layer and tight junctions, and differentiation of splenic Foxp3+ Treg cells of the neonatal mice before any clinical side effects were observed. The potent ability of each antibiotic to affect the makeup of intestinal commensal microbiota may be a key determinant of the spectrum of antibiotics and influence the health of the host animal, at least partly.

Lactobacillus brevis KB290 With Vitamin A Ameliorates Murine Intestinal Inflammation Associated With the Increase of CD11c+ Macrophage/CD103- Dendritic Cell Ratio

BACKGROUND

The ratio of colonic anti-inflammatory CD11c+ macrophages (MPs) to inflammatory CD103- dendritic cells (DCs) plays pivotal roles in intestinal inflammation. Little is known about how the ratio is regulated by lactic acid bacteria (LAB) and bifidobacteria (Bif). We investigated the contribution of LAB/Bif to this ratio.

METHODS

We established an in vitro experimental system using human myeloblastic KG-1 cells, which differentiate into CD11c+ MP-like (CD11c+ MPL) and CD103- DC-like (CD103- DCL) cells, and explored effective LAB/Bif strains. The selected strain's effect on the colonic CD11c+ MP/CD103- DC ratio and intestinal inflammation was examined in mice, and the strain's underlying mechanisms were investigated in vitro.

RESULTS

We screened 19 strains of LAB/Bif, and found that Lactobacillus brevis KB290 (KB290) increased the CD11c+ MPL/CD103- DCL cell ratio only in the presence of a vitamin A (VA) metabolite, retinoic acid (RA). Supplementation of KB290 with VA increased the CD11c+ MP/CD103- DC ratio in healthy mouse and prevented the disruption of the ratio during colitis. Supplementation of KB290 with pro-VA (β-carotene) also increased the ratio in healthy mouse and ameliorated the development of colitis. The ratio was increased by reduction of CD103- DCs (or CD103- DCL cells). Our in vitro data suggested that KB290 induced cell death in CD103- DCL cells in the presence of RA signaling.

CONCLUSIONS

Supplementation of KB290 with VA increases the colonic CD11c+ MP/CD103- DC ratio associated with the amelioration of murine colitis, suggesting a possible way to control intestinal inflammation by LAB.

Soluble Mediators From Lactobacillus rhamnosus Gorbach-Goldin Support Intestinal Barrier Function in Rats After Massive Small-Bowel Resection

BACKGROUND

Intestinal barrier plays an essential role in maintaining gastrointestinal health. This study aimed to explore the effects of a soluble mediator preparation derived from Lactobacillus rhamnosus Gorbach-Goldin (LGG) on intestinal barrier function in a rat model of short bowel syndrome (SBS).

METHODS

Six-week-old male Sprague-Dawley rats underwent 80% small-bowel resection (SBR) and then were supplemented with water (SBS), 5 × 10⁸ colony-forming unit viable LGG (SBS+LGG), or the LGG soluble mediators (SBS+LSM) in an equivalent dose to LGG by intragastric gavage daily from day 2 throughout day 14 after operation. Rats that underwent bowel transection and reanastomosis were used as the sham group. Body weight, ileum histology, intestinal permeability and bacterial translocation, inflammatory cytokines, and tight junction protein expressions of ileum were evaluated.

RESULTS

Animals undergoing SBR showed higher intestinal permeability and decreased expression of tight junction proteins in the ileum than sham group. Both SBS+LGG and SBS+LSM groups had reduced bacterial translocation and intestinal permeability as compared with the SBS group, with lower levels of serum endotoxin and tumor necrotizing factor alpha in ileum tissues. Moreover, the SBS+LSM group showed better body weight gain, lower endotoxin and FD-40 levels, and higher expressions of claudin-1 and claudin-4 in ileum than the SBS+LGG group.

CONCLUSION

Enteral supplementation of LSMs or viable LGG can ameliorate intestinal barrier disruption in a rat model of SBS. The LSM preparation not only mimicked biological effects of viable LGG but also was revealed to be more effective in reducing inflammation and supporting intestinal barrier function.

Probiotic Modulation of Innate Cell Pathogen Sensing and Signaling Events

There is a growing body of evidence documenting probiotic bacteria to have a beneficial effect to the host through their ability to modulate the mucosal immune system. Many probiotic bacteria can be considered to act as either immune activators or immune suppressors, which have appreciable influence on homeostasis, inflammatory- and suppressive-immunopathology. What is becoming apparent is the ability of these probiotics to modulate innate immune responses via direct or indirect effects on the signaling pathways that drive these activatory or suppressive/tolerogenic mechanisms. This review will focus on the immunomodulatory role of probiotics on signaling pathways in innate immune cells: from positive to negative regulation associated with innate immune cells driving gut mucosal functionality. Research investigations have shown probiotics to modulate innate functionality in many ways including, receptor antagonism, receptor expression, binding to and expression of adaptor proteins, expression of negative regulatory signal molecules, induction of micro-RNAs, endotoxin tolerisation and finally, the secretion of immunomodulatory proteins, lipids and metabolites. The detailed understanding of the immunomodulatory signaling effects of probiotic strains will facilitate strain-specific selective manipulation of innate cell signal mechanisms in the modulation of mucosal adjuvanticity, immune deviation and tolerisation in both healthy subjects and patients with inflammatory and suppressive pathology.