Saccharomyces boulardii improves intestinal epithelial cell restitution by inhibiting αvβ5 integrin activation state

A comprehensive guide to assess gut mycobiome and its role in pathogenesis and treatment of inflammatory bowel disease

Inflammatory bowel disease (IBD) is an immune mediated chronic inflammatory disorder of gastrointestinal tract, which has underlying multifactorial pathogenic determinants such as environmental factors, susceptibility genes, gut microbial dysbiosis and a dysregulated immune response. Human gut is a frequent inhabitant of complex microbial ecosystem encompassing bacteria, viruses, parasites, fungi and other microorganisms that have an undisputable role in maintaining balanced homeostasis. All of these microbes interact with immune system and affect human gut physiology either directly or indirectly with interaction of each other. Intestinal fungi represent a smaller but crucial component of the human gut microbiome. Besides interaction with bacteriome and virome, it helps in balancing homoeostasis between pathophysiological and physiological processes, which is often dysregulated in patients with IBD. Understanding of gut mycobiome and its clinical implications are still in in its infancy as opposed to bacterial component of gut microbiome, which is more often focused. Modulation of gut mycobiome represents a novel and promising strategy in the management of patients with IBD. Emerging mycobiome-based therapies such as diet interventions, fecal microbiota transplantation (FMT), probiotics (both fungal and bacterial strains) and antifungals exhibit substantial effects in calibrating the gut mycobiome and restoring dysbalanced immune homeostasis by restoring the core gut mycobiome. In this review, we summarized compositional and functional diversity of the gut mycobiome in healthy individuals and patients with IBD, gut mycobiome dysbiosis in patients with IBD, host immune-fungal interactions and therapeutic role of modulation of intestinal fungi in patients with IBD.

Differential modulation of cellular phenotype and drug sensitivity by extracellular matrix proteins in primary and metastatic pancreatic cancer cells

Pancreatic ductal adenocarcinoma (PDAC) is reported to be the third highest cause of cancer-related deaths in the United States. PDAC is known for its high proportion of stroma, which accounts for 90% of the tumor mass. The stroma is made up of extracellular matrix (ECM) and nonmalignant cells such as inflammatory cells, cancer-associated fibroblasts, and lymphatic and blood vessels. Here, we decoupled the effects of the ECM on PDAC cell lines by culturing cells on surfaces coated with different ECM proteins. Our data show that the primary tumor-derived cell lines have different morphology depending on the ECM proteins on which they are cultured, while metastatic lesion-derived PDAC lines' morphology does not change with respect to the different ECM proteins. Similarly, ECM proteins modulate the proliferation rate and the gemcitabine sensitivity of the primary tumor PDAC cell lines, but not the metastatic PDAC lines. Lastly, transcriptomics analysis of the primary tumor PDAC cells cultured on different ECM proteins reveals the regulation of various pathways, such as cell cycle, cell-adhesion molecules, and focal adhesion, including the regulation of several integrin genes that are essential for ECM recognition.

The Probiotic Strains Bifidοbacterium lactis, Lactobacillus acidophilus, Lactiplantibacillus plantarum and Saccharomyces boulardii Regulate Wound Healing and Chemokine Responses in Human Intestinal Subepithelial Myofibroblasts

Bifidobacterium lactis, Lactobacillus acidophilus, Lactiplantibacillus plantarum and Saccharomyces boulardii are common probiotic supplements. Colonic subepithelial myofibroblasts (cSEMFs) are actively involved in mucosal wound healing and inflammation. cSEMFs, isolated from healthy individuals, were stimulated with 102 or 104 cfu/mL of these probiotic strains alone and in combination, and their effect on chemokine and wound healing factor expression was assessed by qRT-PCR, ELISA and Sircol Assay, and on cSEMFs migration, by Wound Healing Assay. These strains remained viable and altered cSEMFs’ inflammatory and wound healing behavior, depending on the strain and concentration. cSEMFs treated with a combination of the four probiotics had a moderate, but statistically significant, increase in the mRNA and/or protein expression of chemokines CXCL1, CXCL2, CXCL4, CXCL8, CXCL10, CCL2 and CCL5, and healing factors, collagen type I and III, fibronectin and tissue factor. In contrast, when each strain was administered alone, different effects were observed, with greater increase or decrease in chemokine and healing factor expression, which was balanced by the mixture. Overall, this study highlights that the use of multiple probiotic strains can potentially alert the gut mucosal immune system and promote wound healing, having a better effect on mucosal immunity than the use of single probiotics.

Gut Mycobiome in Patients With Chronic Kidney Disease Was Altered and Associated With Immunological Profiles

Objectives

Mounting evidence suggests that bacterial dysbiosis and immunity disorder are associated with patients with chronic kidney disease (CKD), but the mycobiome is beginning to gain recognition as a fundamental part of our microbiome. We aim to characterize the profile of the mycobiome in the gut of CKD patients and its correlation to serum immunological profiles.

Methods and materials

Ninety-two CKD patients and sex-age-body mass index (BMI)-matched healthy controls (HCs) were recruited. Fresh samples were collected using sterile containers. ITS transcribed spacer ribosomal RNA gene sequencing was performed on the samples. An immunoturbidimetric test was used to assess the serum levels of immunological features.

Results

The CKD cohort displayed a different microbial community from that in the HC cohort according to principal coordinate analysis (PCoA). (P=0.001). The comparison of the two cohorts showed that the CKD cohort had significantly higher gut microbial richness and diversity (P<0.05). The CKD cohort had lower abundances of Candida, Bjerkandera, Rhodotorula, and Ganoderma compared to the HC cohort, while it had higher Saccharomyces (P<0.05). However, the microbial community alteration was inconsistent with the severity of kidney damage in patients, as only patients in CKD stage 1~3 had differed microbial community concerning for HCs based on PCoA (P<0.05). The serum concentration of the kappa light chain in CKD patients was positively associated with Saccharomyces, whereas the it was negatively associated with Ganoderma (P<0.05).

Conclusions

Not only was gut mycobiome dysbiosis observed in CKD patients, but the dysbiosis was also associated with the immunological disorder. These findings suggest that therapeutic strategies targeting gut mycobiome might be effective.

In vitro bioactivities of coffee brews fermented with the probiotics Lacticaseibacillus rhamnosus GG and Saccharomyces boulardii CNCM-I745

Previously, we demonstrated the production of bioactive metabolites (e.g., indole-3-lactate, 4-hydroxyphenyllactate, 3-phenyllactate, 2-isopropylmalate) by the probiotics Lacticaseibacillus rhamnosus GG and Saccharomyces boulardii CNCM-I745 during coffee brew fermentation. However, it remains unclear if in situ production of bioactive metabolites confers additional health benefits to coffee brews. Here, we aimed to investigate the in vitro bioactivities of freeze-dried cell-free coffee supernatants fermented with L. rhamnosus GG and/or S. boulardii CNCM-I745, compared to non-fermented coffee supernatants. In vitro bioactivity assays pertained to α-amylase and α-glucosidase inhibition, antiglycative activities, anti-proliferation against human cancer cell lines (MCF-7, HCT116, and HepG2), cellular antioxidant activities, and anti-inflammatory activities. We demonstrated that non-fermented coffee supernatants displayed weak starch hydrolase inhibition (IC₅₀ > 36.00 mg/mL), but otherwise displayed strong anti-glycative (IC₅₀ 0.71-0.74 mg/mL), anti-proliferative (IC₅₀ 0.45, 0.36, and < 0.5 mg/mL for MCF-7, HCT116, and HepG2 respectively), cellular antioxidant (85,844.22 µmol quercetin equivalents/100 g coffee supernatant), and anti-inflammatory activities (35.7% reduction in nitrite production at 0.13 mg/mL). In all the assays tested, probiotic fermented coffee supernatants exhibited very similar bioactivities compared to non-fermented coffee supernatants, and improvements were not observed. Overall, in vitro bioactivities of coffee brews were not improved via in situ metabolite production by L. rhamnosus GG and/or S. boulardii CNCM-I745. Therefore, bioactive metabolites produced during probiotic-induced food fermentations may not necessarily confer additional health benefits compared to non-fermented counterparts.

1H-NMR metabolomics response to a realistic diet contamination with the mycotoxin deoxynivalenol: Effect of probiotics supplementation

Low-level contamination of food and feed by deoxynivalenol (DON) is unavoidable. We investigated the effects of subclinical treatment with DON, and supplementation with probiotic yeast Saccharomyces cerevisiae boulardii I1079 as a preventive strategy in piglets. Thirty-six animals were randomly assigned to either a control diet, a diet contaminated with DON (3 mg/kg), a diet supplemented with yeast (4 × 10⁹ CFU/kg), or a DON-contaminated diet supplemented with yeast, for four weeks. Plasma and tissue samples were collected for biochemical analysis,¹H-NMR untargeted metabolomics, and histology. DON induced no significant modifications in biochemical parameters. However, lesion scores were higher and metabolomics highlighted alterations of amino acid and 2-oxocarboxylic acid metabolism. Administering yeast affected aminoacyl-tRNA synthesis and amino acid and glycerophospholipid metabolism. Yeast supplementation of piglets exposed to DON prevented histological alterations, and partial least square discriminant analysis emphasised similarity between the metabolic profiles of their plasma and that of the control group. The effect on liver metabolome remained marginal, indicating that the toxicity of the mycotoxin was not eliminated. These findings show that the ¹H-NMR metabolomics profile is a reliable biomarker to assess subclinical exposure to DON, and that supplementation with S. cerevisiae boulardii increases the resilience of piglets to this mycotoxin.

Investigating the Proteomic Profile of HT-29 Colon Cancer Cells After Lactobacillus kefiri SGL 13 Exposure Using the SWATH Method

Despite some studies revealed that kefir acts on different cancers, such as colorectal cancer, the proteomic changes that occur in the colon cancer cells remain to be explored. In this study, the proteomic analysis was combined with determination of kefir characteristics (e.g., adhesion capacity, gastrointestinal and antibiotic resistances), in order to confirm its use as a probiotic. Therefore, a label-free strategy based on SWATH-MS was applied to investigate the proteomic profile of HT-29 cells after exposure for 24 h to a specific strain of Lactobacillus kefiri named SGL 13. We identified a total of 60 differentially expressed proteins in HT-29 cells, among which most are located into the extracellular exosome, playing important/crucial roles in translation and cell adhesion, as indicated by the enrichment analysis. The eIF2 and retinoid X receptor activation pathways appeared to be correlated with the anti-tumoral effect of SGL 13. Immunoblot analysis showed an increase in Bax and a decrease in caspase 3 and mutant p53, and ELISA assay revealed inhibition of IL-8 secretion from HT-29 cells stimulated with LPS upon SGL 13 treatment, suggesting pro-apoptotic and anti-inflammatory properties of kefir. In conclusion, the results of this study, the first of its kind using co-culture of kefir and colon cancer cells, demonstrate that L. kefiri SGL 13 possesses probiotic potency and contribute to elucidate the molecular mechanisms involved in the L. kefiri-colon cancer cell interactions.

The effects of probiotic Saccharomyces boulardii on the mental health, quality of life, fatigue, pain, and indices of inflammation and oxidative stress in patients with multiple sclerosis: study protocol for a double-blind randomized controlled clinical trial

BACKGROUND

The relationship between gut dysbiosis and inflammatory diseases including multiple sclerosis (MS) is presently recognized as an important health issue. It has been established that some bacterial probiotic strains are effective in treating MS. This study will investigate the effect of yeast probiotic Saccharomyces boulardii (SB) supplements on mental health, quality of life, fatigue, pain, and indices of inflammation and oxidative stress in MS patients.

METHODS/DESIGN

In this double-blind randomized controlled two-group parallel trial, 50 MS patients who meet the inclusion criteria will be recruited from outpatient settings. They will be randomly allocated to 4 months of daily placebo or the SB probiotic intervention. Blood samples will be taken from each participant at the baseline and after the intervention period to assess inflammation and oxidative stress. The primary endpoint will be the changes in their mental health evaluated by the 28-item General Health Questionnaire. The secondary endpoints include changes in: (1) quality of life, evaluated by the 36-item Short Form Questionnaire, (2) fatigue, evaluated by the Fatigue Severity Scale, (3) pain, evaluated by a visual analogue scale, and (4) serum levels of indices of inflammatory stress (high-sensitivity C-reactive protein) and oxidative stress (malondialdehyde and total antioxidant capacity). Moreover, any adverse events and side effects due to the intervention will be documented.

DISCUSSION

There is a need to discover safe and practical methods for managing the symptoms of MS. This trial will gather evidence on the effects of a probiotic.

TRIAL REGISTRATION

Iranian Clinical Trial Registry, IRCT20161022030424N1 . Registered on 9 April 2018.

Beneficial effects of Saccharomyces boulardii CNCM I-745 on clinical disorders associated with intestinal barrier disruption

Intestinal barrier defects lead to "leaky gut syndrome", defined as an increase in intestinal permeability that allows the passage of luminal content into intestinal tissue and the bloodstream. Such a compromised intestinal barrier is the main factor underlying the pathogenesis of inflammatory bowel disease, but also commonly occurs in various systemic diseases such as viral infections and metabolic syndrome. The non-pathogenic yeast Saccharomyces boulardii CNCM I-745 has demonstrated its effectiveness as a probiotic in the prevention and treatment of antibiotic-associated, infectious and functional diarrhea. Via multiple mechanisms of action implicated in intestinal barrier function, S. boulardii has beneficial effects on altered intestinal microbiota and epithelial barrier defects in different pathologies. The well-studied probiotic yeast S. boulardii plays a crucial role in the preservation and/or restoration of intestinal barrier function in multiple disorders. This could be of major interest in diseases characterized by alterations in intestinal barrier function.

Saccharomyces cerevisiae Boulardii Reduces the Deoxynivalenol-Induced Alteration of the Intestinal Transcriptome

Type B trichothecene mycotoxin deoxynivalenol (DON) is one of the most frequently occurring food contaminants. By inducing trans-activation of a number of pro-inflammatory cytokines and increasing the stability of their mRNA, trichothecene can impair intestinal health. Several yeast products, especially Saccharomyces cerevisiae, have the potential for improving the enteric health of piglets, but little is known about the mechanisms by which the administration of yeast counteracts the DON-induced intestinal alterations. Using a pig jejunum explant model, a whole-transcriptome analysis was performed to decipher the early response of the small intestine to the deleterious effects of DON after administration of S. cerevisiae boulardii strain CNCM I-1079. Compared to the control condition, no differentially expressed gene (DE) was observed after treatment by yeast only. By contrast, 3619 probes-corresponding to 2771 genes-were differentially expressed following exposure to DON, and 32 signaling pathways were identified from the IPA software functional analysis of the set of DE genes. When the intestinal explants were treated with S. cerevisiae boulardii prior to DON exposure, the number of DE genes decreased by half (1718 probes corresponding to 1384 genes). Prototypical inflammation signaling pathways triggered by DON, including NF-κB and p38 MAPK, were reversed, although the yeast demonstrated limited efficacy toward some other pathways. S. cerevisiae boulardii also restored the lipid metabolism signaling pathway, and reversed the down-regulation of the antioxidant action of vitamin C signaling pathway. The latter effect could reduce the burden of DON-induced oxidative stress. Altogether, the results show that S. cerevisiae boulardii reduces the DON-induced alteration of intestinal transcriptome, and point to new mechanisms for the healing of tissue injury by yeast.

Saccharomyces boulardii CNCM I-745 Restores intestinal Barrier Integrity by Regulation of E-cadherin Recycling

BACKGROUND AND AIMS

Alteration in intestinal permeability is the main factor underlying the pathogenesis of many diseases affecting the gut, such as inflammatory bowel disease [IBD]. Characterization of molecules targeting the restoration of intestinal barrier integrity is therefore vital for the development of alternative therapies. The yeast Saccharomyces boulardii CNCM I-745 [Sb], used to prevent and treat antibiotic-associated infectious and functional diarrhea, may have a beneficial effect in the treatment of IBD.

METHODS

We analyzed the impact of Sb supernatant on tissue integrity and components of adherens junctions using cultured explants of colon from both IBD and healthy patients. To evaluate the pathways by which Sb regulates the expression of E-cadherin at the cell surface, we developed in vitro assays using human colonic cell lines, including cell aggregation, a calcium switch assay, real-time measurement of transepithelial electrical resistance [TEER] and pulse-chase experiments.

RESULTS

We showed that Sb supernatant treatment of colonic explants protects the epithelial morphology and maintains E-cadherin expression at the cell surface. In vitro experiments revealed that Sb supernatant enhances E-cadherin delivery to the cell surface by re-routing endocytosed E-cadherin back to the plasma membrane. This process, involving Rab11A-dependent recycling endosome, leads to restoration of enterocyte adherens junctions, in addition to the overall restoration and strengthening of intestinal barrier function.

CONCLUSION

These findings open new possibilities of discovering novel options for prevention and therapy of diseases that affect intestinal permeability.

Mechanisms of Action of Probiotics and the Gastrointestinal Microbiota on Gut Motility and Constipation

Constipation is a common and burdensome gastrointestinal disorder that may result from altered gastrointestinal motility. The effect of probiotics on constipation has been increasingly investigated in both animal and human studies, showing promising results. However, there is still uncertainty regarding the mechanisms of action of probiotics on gut motility and constipation. Several factors are vital to normal gut motility, including immune and nervous system function, bile acid metabolism and mucus secretion, and the gastrointestinal microbiota and fermentation; an imbalance or dysfunction in any of these components may contribute to aberrant gut motility and, consequently, symptoms of constipation. For example, adults with functional constipation have significantly decreased numbers of bifidobacteria (with one study showing a mean difference of 1 log₁₀/g) and lactobacilli (mean difference, 1.4 log₁₀/g) in stool samples, as well as higher breath methane, compared with control subjects. Modifying the gut luminal environment with certain probiotic strains may affect motility and secretion in the gut and, hence, provide a benefit for patients with constipation. Therefore, this review explores the mechanisms through which probiotics may exert an effect on gut motility and constipation. Nevertheless, the majority of current evidence is derived from animal studies, and therefore, further human studies are needed to determine the mechanisms through specific probiotic strains that might be effective in constipation.

Impact of probiotic Saccharomyces boulardii on the gut microbiome composition in HIV-treated patients: A double-blind, randomised, placebo-controlled trial

Dysbalance in gut microbiota has been linked to increased microbial translocation, leading to chronic inflammation in HIV-patients, even under effective HAART. Moreover, microbial translocation is associated with insufficient reconstitution of CD4+T cells, and contributes to the pathogenesis of immunologic non-response. In a double-blind, randomised, placebo-controlled trial, we recently showed that, compared to placebo, 12 weeks treatment with probiotic Saccharomyces boulardii significantly reduced plasma levels of bacterial translocation (Lipopolysaccharide-binding protein or LBP) and systemic inflammation (IL-6) in 44 HIV virologically suppressed patients, half of whom (n = 22) had immunologic non-response to antiretroviral therapy (<270 CD4+Tcells/μL despite long-term suppressed viral load). The aim of the present study was to investigate if this beneficial effect of the probiotic Saccharomyces boulardii is due to modified gut microbiome composition, with a decrease of some species associated with higher systemic levels of microbial translocation and inflammation. In this study, we used 16S rDNA gene amplification and parallel sequencing to analyze the probiotic impact on the composition of the gut microbiome (faecal samples) in these 44 patients randomized to receive oral supplementation with probiotic or placebo for 12 weeks. Compared to the placebo group, in individuals treated with probiotic we observed lower concentrations of some gut species, such as those of the Clostridiaceae family, which were correlated with systemic levels of bacterial translocation and inflammation markers. In a sub-study of these patients, we observed significantly higher parameters of microbial translocation (LBP, soluble CD14) and systemic inflammation in immunologic non-responders than in immunologic responders, which was correlated with a relative abundance of specific gut bacterial groups (Lachnospiraceae genus and Proteobacteria). Thus, in this work, we propose a new therapeutic strategy using the probiotic yeast S. boulardii to modify gut microbiome composition. Identifying pro-inflammatory species in the gut microbiome could also be a useful new marker of poor immune response and a new therapeutic target.

Probiotic Saccharomyces boulardii CNCM I-745 prevents outbreak-associated Clostridium difficile-associated cecal inflammation in hamsters

C. difficile infection (CDI) is a common debilitating nosocomial infection associated with high mortality. Several CDI outbreaks have been attributed to ribotypes 027, 017, and 078. Clinical and experimental evidence indicates that the nonpathogenic yeast Saccharomyces boulardii CNCM I-745 (S.b) is effective for the prevention of CDI. However, there is no current evidence suggesting this probiotic can protect from CDI caused by outbreak-associated strains. We used established hamster models infected with outbreak-associated C. difficile strains to determine whether oral administration of live or heat-inactivated S.b can prevent cecal tissue damage and inflammation. Hamsters infected with C. difficile strain VPI10463 (ribotype 087) and outbreak-associated strains ribotype 017, 027, and 078 developed severe cecal inflammation with mucosal damage, neutrophil infiltration, edema, increased NF-κB phosphorylation, and increased proinflammatory cytokine TNFα protein expression. Oral gavage of live, but not heated, S.b starting 5 days before C. difficile infection significantly reduced cecal tissue damage, NF-κB phosphorylation, and TNFα protein expression caused by infection with all strains. Moreover, S.b-conditioned medium reduced cell rounding caused by filtered supernatants from all C. difficile strains. S.b-conditioned medium also inhibited toxin A- and B-mediated actin cytoskeleton disruption. S.b is effective in preventing C. difficile infection by outbreak-associated via inhibition of the cytotoxic effects of C. difficile toxins.

Fungal Dysbiosis in Mucosa-associated Microbiota of Crohn's Disease Patients

BACKGROUND AND AIMS

Gut microbiota is involved in many physiological functions and its imbalance is associated with several diseases, particularly with inflammatory bowel diseases. Mucosa-associated microbiota could have a key role in induction of host immunity and in inflammatory process. Although the role of fungi has been suggested in inflammatory disease pathogenesis, the fungal microbiota has not yet been deeply explored. Here we analysed the bacterial and fungal composition of the mucosa-associated microbiota of Crohn's disease patients and healthy subjects.

METHODS

Our prospective, observational study evaluated bacterial and fungal composition of mucosa-associated microbiota of 23 Crohn's disease patients [16 in flare, 7 in remission] and 10 healthy subjects, using 16S [MiSeq] and ITS2 [pyrosequencing] sequencing, respectively. Global fungal load was assessed by real time quantitative polymerase chain reaction.

RESULTS

Bacterial microbiota in Crohn's disease patients was characterised by a restriction in biodiversity. with an increase of Proteobacteria and Fusobacteria. Global fungus load was significantly increased in Crohn's disease flare compared with healthy subjects [p < 0.05]. In both groups, the colonic mucosa-associated fungal microbiota was dominated by Basidiomycota and Ascomycota phyla. Cystofilobasidiaceae family and Candida glabrata species were overrepresented in Crohn's disease. Saccharomyces cerevisiae and Filobasidium uniguttulatum species were associated with non-inflamed mucosa, whereas Xylariales order was associated with inflamed mucosa.

CONCLUSIONS

Our study confirms the alteration of the bacterial microbiota and is the first demonstration of the existence of an altered fungal microbiota in Crohn's disease patients, suggesting that fungi may play a role in pathogenesis.

Non-Saccharomyces yeasts protect against epithelial cell barrier disruption induced by Salmonella enterica subsp. enterica serovar Typhimurium

The human gastrointestinal epithelium makes up the largest barrier separating the body from the external environment. Whereas invasive pathogens cause epithelial barrier disruption, probiotic micro-organisms modulate tight junction regulation and improve epithelial barrier function. In addition, probiotic strains may be able to reduce epithelial barrier disruption caused by pathogenic species. The aim of this study was to explore non-Saccharomyces yeast modulation of epithelial cell barrier function in vitro. Benchmarking against established probiotic strains, we evaluated the ability of four nonpathogenic yeast species to modulate transepithelial electrical resistance (TER) across a monolayer of differentiated human colonocytes (Caco-2 cells). Further, we assessed yeast modulation of a Salmonella Typhimurium-induced epithelial cell barrier function insult. Our findings demonstrate distinct patterns of non-Saccharomyces yeast modulation of epithelial cell barrier function. While the established probiotic yeast Saccharomyces boulardii increased TER across a Caco-2 monolayer by 30%, Kluyveromyces marxianus exhibited significantly stronger properties of TER enhancement (50% TER increase). In addition, our data demonstrate significant yeast-mediated modulation of Salmonella-induced epithelial cell barrier disruption and identify K. marxianus and Metschnikowia gruessii as two non-Saccharomyces yeasts capable of protecting human epithelial cells from pathogen invasion.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study demonstrates distinct patterns of non-Saccharomyces yeast modulation of epithelial cell barrier function in vitro. Further, our data demonstrate significant yeast-mediated modulation of Salmonella Typhimurium-induced epithelial cell barrier disruption and identify Kluyveromyces marxianus and Metschnikowia gruessii as two non-Saccharomyces yeasts capable of protecting human epithelial cells from pathogen invasion. This study is the first to demonstrate significant non-Saccharomyces yeast-mediated epithelial cell barrier protection from Salmonella invasion, thus encouraging future efforts aimed at confirming the observed effects in vivo and driving further strain development towards novel yeast probiotics.

Effect of probiotics (Saccharomyces boulardii) on microbial translocation and inflammation in HIV-treated patients: a double-blind, randomized, placebo-controlled trial

BACKGROUND

Microbial translocation has been associated with an increase in immune activation and inflammation in HIV infection despite effective highly active antiretroviral therapy. It has been shown that some probiotics have a beneficial effect by reducing intestinal permeability and, consequently, microbial translocation.

OBJECTIVES

To assess changes in microbial translocation and inflammation after treatment with probiotics (Saccharomyces boulardii) in HIV-1-infected patients with virologic suppression.

METHODS

A double-blind, randomized, placebo-controlled trial was conducted in 44 nonconsecutive HIV-1-infected patients with viral load of <20 copies per milliliter for at least 2 years. Patients were randomized to oral supplementation with probiotics or placebo during 12 weeks. Markers of microbial translocation (lipopolysaccharide-binding protein [LBP] and soluble CD14), inflammation (interleukin 6 [IL-6], tumor necrosis factor alpha, interferon gamma, high-sensitivity C-reactive protein), and immunological and clinical data were determined before and after the intervention and 3 months after treatment discontinuation. Quantitative variables were compared using the Mann-Whitney U test, and categorical variables were compared using the Fisher exact test.

RESULTS

After 12 weeks of treatment, differences between the probiotic arm and the placebo arm were observed in LBP values (-0.30 vs +0.70 pg/mL) and IL-6 (-0.60 vs +0.78 pg/mL). These differences were also noted at 3 months after treatment withdrawal. Qualitative analysis was performed, defining a variable as "decreased" or "increased" from baseline LBP. A significant decrease of LBP at 12 weeks of treatment was observed (57.9% patients in the probiotic group vs 6.2% in the placebo group, P = 0.002).

CONCLUSIONS

Treatment with S. boulardii decreases microbial translocation (LBP) and inflammation parameters (IL-6) in HIV-1-infected patients with long-term virologic suppression.

Gut fungal microbiota: the Yin and Yang of inflammatory bowel disease

The prevalence of inflammatory bowel diseases (IBD) has been steadily increasing since 1960. They are widespread throughout Europe, North America, China, and Japan and are emerging as a global disease. The equilibrium among epithelial cells, the immune system, and the related microbiota seems to be paramount in ensuring the absence of these IBD. The role of bacteria in the setting of the gut microbiota has been thoroughly documented, but the role of fungi, which are less abundant, needs to be investigated. Our understanding of the fungal microbiota composition and its impact on IBD has greatly increased in the past 8 years. In this review, we compiled data obtained for the composition of fungal gut microbiota. Special attention was paid to the various effects of this microbial community on the IBD, i.e., the mechanisms and immune pathways involved in these interactions.

Microbial ecological agents and inflammatory bowel disease

Inflammatory bowel disease (IBD), including ulcerative colitis (UC) and Crohn's disease (CD), is a chronic non-specific inflammatory condition of the gastrointestinal tract with unknown etiology. During the exploration of the etiology, treatment and other aspects of IBD, it has been gradually realized that microbial ecological agents (MEAs) are helpful in the treatment of IBD. This article reviews the relationship between MEAs and IBD with regard to the intestinal environment in IBD, the therapeutic effect of MEA in IBD and the possible mechanisms involved.

Ulcerative colitis and intestinal flora

Ulcerative colitis (UC) is a serious chronic inflammatory disease characterized by recurrent episodes of intestinal ulcer, diarrhea, bloody stools and abdominal pain. The pathogenesis of UC is thought to be associated wit genetic susceptibility, mucosal immunity and intestinal flora. Compared with normal people, UC patients often develop different degrees of dysbacteriosis, which mainly manifests as reduced number of good microorganisms and increased number of conditional pathogenic bacteria. In this paper, we will discuss the distribution of intestinal flora, mainly potential pathogenic bacteria and good microorganisms, in patients with UC.