Role of probiotic therapy in IBD

Lactobacillus fermentum CKCC1858 alleviates hyperlipidemia in golden hamsters on a high-fat diet via modulating gut microbiota

To investigate the effect of probiotic Lactobacillus fermentum CKCC1858, LF on the prevention of hyperlipidemia and its correlation with gut microbiota, golden hamsters were fed a high-fat diet alone or in combination with the probiotic for 6 weeks. The results showed that the LF intervention alleviated HFD-induced hyperlipidemia and liver damage, as evidenced by the reduced serum lipid profile levels and liver function markers. More importantly, the LF intervention attenuated HFD-induced microbiota dysbiosis by enhancing the abundance of SCFA-producing bacteria and reshaping the metabolic functions of the gut microbiota, likely contributing to its pronounced preventive effects on hyperlipidemia. This study elucidated the mechanism of the preventive effect of probiotics on hyperlipidemia in terms of regulating gut microbiota, and provided suggestions for regulating gut microbiota through probiotic interventions to improve lipid metabolism.

Probiotic potentials of lactic acid bacteria isolated from Egyptian fermented food

Lactic acid bacteria (LAB) are of major concern due to their health benefits. Fermented food products comprise variable LAB demonstrating probiotic properties. Discovering and evaluating new probiotics in fermented food products poses a global economic and health importance. Therefore, the present work aimed to investigate and evaluate the probiotic potentials of LAB strains isolated from Egyptian fermented food. In this study, we isolated and functionally characterized 100 bacterial strains isolated from different Egyptian fermented food sources as probiotics. Only four LAB strains amongst the isolated LAB showed probiotic attributes and are considered to be safe for their implementation as feed or dietary supplements. Additionally, they were shown to exert antimicrobial activities against pathogenic bacteria and anticancer effects against the colon cancer cell line Caco-2. The Enterococcus massiliensis IS06 strain was exclusively reported in this study as a probiotic strain with high antimicrobial, antioxidant, and anti-colon cancer activity. Hitherto, few studies have focused on elucidating the impact of probiotic supplementation in vivo. Therefore, in the current study, the safety of the four strains was tested in vivo through the supplementation of rats with potential probiotic strains for 21 days. The results revealed that probiotic bacterial supplementation in rats did not adversely affect the general health of rats. The Lactiplantibacillus plantarum IS07 strain significantly increased the growth performance of rats. Furthermore, the four strains exhibited increased levels of antioxidants such as superoxide dismutase and glutathione in vivo. Consistently, all strains also showed high antioxidant activity of the superoxide dismutase enzyme in vitro. Overall, these findings demonstrated that these isolated potential probiotics harbor desirable characteristics and can be applied widely as feed additives for animals or as dietary supplements for humans to exert their health benefits and combat serious diseases.

Therapeutic efficacy and underlying mechanisms of Gastrodia elata polysaccharides on dextran sulfate sodium-induced inflammatory bowel disease in mice: Modulation of the gut microbiota and improvement of metabolic disorders

Inflammatory bowel disease (IBD) is a chronic inflammatory gastrointestinal disease, and an imbalance in the gut microbiota is a critical factor in its development. Gastrodia elata (G. elata), an Orchidaceae plant, is recognized for its nutritional and medicinal value. Studies have shown that G. elata polysaccharides (GBP) have anti-inflammatory properties that may ameliorate IBD. However, the therapeutic effects of GBP on gut microbiota metabolism remain unknown. Therefore, we aimed to examine the therapeutic potential of G. elata extract and GBP in dextran sulfate sodium (DSS)-induced IBD mice. GBP demonstrated the best therapeutic effect by reducing IBD symptoms in mice to the greatest extent. Administering GBP resulted in significant increases in the relative abundances of bacteria with potential anti-inflammatory effects, such as Ligilactobacillus and Alloprevotella, and decreases in the levels of bacteria associated with proinflammatory responses, such as Bacteroides and Escherichia-Shigella. Furthermore, 36 significant differential metabolites between the model and GBP groups were identified in feces, which were mainly enriched in amino acid metabolism, including tryptophan and cysteine, vitamin B6 metabolism and steroid hormone biosynthesis. Consequently, investigating the metabolic regulation of the gut microbiota is a promising approach to evaluate the therapeutic effect of GBP on IBD.

The emerging microbiome-based approaches to IBD therapy: From SCFAs to urolithin A

Inflammatory bowel disease (IBD) is a group of chronic gastrointestinal inflammatory conditions which can be life-threatening, affecting both children and adults. Crohn's disease and ulcerative colitis are the two main forms of IBD. The pathogenesis of IBD is complex and involves genetic background, environmental factors, alteration in gut microbiota, aberrant immune responses (innate and adaptive), and their interactions, all of which provide clues to the identification of innovative diagnostic or prognostic biomarkers and the development of novel treatments. Gut microbiota provide significant benefits to its host, most notably via maintaining immunological homeostasis. Furthermore, changes in gut microbial populations may promote immunological dysregulation, resulting in autoimmune diseases, including IBD. Investigating the interaction between gut microbiota and immune system of the host may lead to a better understanding of the pathophysiology of IBD as well as the development of innovative immune- or microbe-based therapeutics. In this review we summarized the most recent findings on innovative therapeutics for IBD, including microbiome-based therapies such as fecal microbiota transplantation, probiotics, live biotherapeutic products, short-chain fatty acids, bile acids, and urolithin A.

Preventive Effects of Long-Term Intake of Plant Oils With Different Linoleic Acid/Alpha-Linolenic Acid Ratios on Acute Colitis Mouse Model

Objective

To investigate the preventive effects of plant oils with different linoleic acid/alpha-linolenic acid (LA/ALA) ratios against colitis symptoms, and dysbiosis of gut microbiota in acute colitis mouse model.

Methods

Sixty male C57BL/6 mice were assigned into six groups (n = 10): three groups were fed low-fat diets with low, medium, and high LA/ALA ratios; and three groups were fed with high-fat diets with low, medium, and high LA/ALA ratios. After 3 months of diet, the mice were exposed to dextran sodium sulfate solution to induce acute colitis. The severity of colitis was estimated by disease activity index (DAI) and histopathological examination. 16S rRNA gene sequencing was used for the analysis of gut microbiota.

Results

Plant oils with a lower LA/ALA ratio showed higher alleviating effects on the symptoms of colitis, which were accompanied by the better prebiotic characteristics manifested as effectively inhibiting the abnormal expansion of phylum Proteobacteria and genus Escherichia-Shigella in the gut microbiota of colitis mouse models.

Conclusion

A potential IBD prevention strategy of reducing the LA/ALA ratio in the daily consumed plant oils was proposed in this study. Furthermore, based on the optimized LA/ALA ratio, this preventive effect might not be weakened by the high intake of plant oils.

Multi-Strain-Probiotic-Loaded Nanoparticles Reduced Colon Inflammation and Orchestrated the Expressions of Tight Junction, NLRP3 Inflammasome and Caspase-1 Genes in DSS-Induced Colitis Model

Gut modulation by multi-strain probiotics (MSPs) is considered an effective strategy for treating inflammatory bowel disease (IBD). The combination of nanomaterial-based MSPs can improve their viability and resistance and can allow their targeted release in the gastrointestinal tract to be achieved. Thus, our aim is to investigate the prospective role of MSP integration into nanomaterials (MSPNPs) and the underlying molecular mechanisms supporting their application as an alternative therapy for IBD using a colitis rat model. To induce the colitis model, rats received 5% DSS, and the efficacy of disease progression after oral administration of MSPNPs was assessed by evaluating the severity of clinical signs, inflammatory response, expressions of tight-junction-related genes and NLRP3 inflammasome and caspase-1 genes, microbial composition and histopathological examination of colonic tissues. The oral administration of MSPNPs successfully alleviated the colonic damage induced by DSS as proved by the reduced severity of clinical signs and fecal calprotectin levels. Compared with the untreated DSS-induced control group, the high activities of colonic NO and MPO and serum CRP levels were prominently reduced in rats treated with MSPNPs. Of note, colonic inflammation in the group treated with MSPNPs was ameliorated by downstreaming NLRP3 inflammasome, caspase-1, IL-18 and IL-1β expressions. After colitis onset, treatment with MSPNPs was more effective than that with free MSPs in restoring the expressions of tight-junction-related genes (upregulation of occludin, ZO-1, JAM, MUC and FABP-2) and beneficial gut microbiota. Interestingly, treatment with MSPNPs accelerated the healing of intestinal epithelium as detected in histopathological findings. In conclusion, the incorporation of MPSs into nanomaterials is recommended as a perspective strategy to overcome the challenges they face and augment their therapeutic role for treating of colitis.

Probiotic based-diet effect on the immune response and induced stress in irradiated mass reared Ceratitis capitata males (Diptera: Tephritidae) destined for the release in the sterile insect technique programs

Ceratitis capitata (medfly) is one of the most devastating crop pests worldwide. The Sterile Insect Technique (SIT) is a control method that is based on the mass rearing of males, their sterilization, and release in the field. However, the effectiveness of the technique depends on the quality of the released males and their fitness. We previously isolated and selected a probiotic bacteria (Enterobacter sp.), from wild-caught medflies, according to criteria that improved biological quality traits of reared medfly males.We firstly evaluated the impact of the irradiation on the expression of different immune and stress genes in the medfly sterile males. Expression was measured at differents time points ranging from 0 to 168 h after irradiation to capture the response of genes with distinct temporal expression patterns. Then, we supplemented the larval diet with previously isolated Enterobacter sp.strain, live and autoclaved at various concentrations to see whether the probiotic treatments affect, through their protective role, the gene expression level, and quality traits. The irradiation had significant effect on the genes attacin, cecropin, PGPR-LC, hsp23, and hsp70 level expression. The expression of attacin and PGPR-LC was up-regulated while that of cecropin was down-regulated. Hsp genes showed decreased levels between 0 and 18 h to peak at 72 h. However, the supplementation of the probiotic strain, either live or autoclaved, was statistically significant only for attacingene. However, significant interaction time x probiotic was noticed for attacin, cecropin, hsp23 and hsp70. The probiotic treatments also improved the quality control parameters like pupal weight. From this work we can conclude that a consortium of parabiotics (autoclaved probiotics) treatment will be recommended in insectaries considering both the beneficial effects on mass reared insects and its general safety for insectary workers and for environment.

Fermented and Germinated Processing Improved the Protective Effects of Foxtail Millet Whole Grain Against Dextran Sulfate Sodium-Induced Acute Ulcerative Colitis and Gut Microbiota Dysbiosis in C57BL/6 Mice

This study investigated the effects of foxtail millet whole grain flours obtained through different processing methods on alleviating symptoms and gut microbiota dysbiosis in a dextran sulfate sodium (DSS)-induced murine colitis model. Sixty C57BL/6 mice were divided into six groups (n = 10 in each group), including one control group (CTRL) without DSS treatment and five DSS-treated groups receiving one of the following diets: AIN-93M standard diet (93MD), whole grain foxtail millet flour (FM), fermented (F-FM), germinated (G-FM), and fermented-germinated foxtail millet flour (FG-FM). A comparison of the disease activity index (DAI) demonstrated that foxtail millet whole grain-based diets could alleviate the symptoms of enteritis to varying degrees. In addition, 16S rRNA gene sequencing revealed that FG-FM almost completely alleviated DSS-induced dysbiosis. Mice on the FG-FM diet also had the lowest plasma IL-6 levels and claudin2 expression levels in the colon, indicating reduced systemic inflammation and improved gut barrier function. This study suggested that foxtail millet whole grain is an attractive choice for the intervention of IBD and gut microbiota dysbiosis, and its prebiotic properties are highly affected by the processing methods.

Unexpected effect of probiotics by Lactococcus lactis subsp. lactis against colitis induced by dextran sulfate sodium in mice

Ulcerative colitis (UC) is a representative intestinal chronic inflammatory disease whose incidence is rapidly increasing worldwide. It was previously shown that some specific probiotics help to guard against UC. In this study, we analyzed the effect of Lactococcus lactis subsp. lactis JCM5805 (L. lactis), which has been put to practical use as a probiotic, on the pathogenesis of UC using a dextran sulfate sodium-induced colitis mouse model. Survival rate, length, and histopathological parameters of the colon were elucidated. Further, the concentrations of inflammatory cytokines in serum were measured. As a result, the oral administration of high-dose L. lactis showed significant decreases in survival rate and colon length. Histopathological analysis showed that a bleeding appearance was observed in the L. lactis group, and the histology scores in the L. lactis group were significantly higher than those in the normal saline group. Furthermore, the levels of interferon gamma, tumor necrosis factor alpha, and interleukin-6 were significantly elevated in the L. lactis group. These results support that high-dose administration of L. lactis deteriorates intestinal inflammation and suggest that the careful selection of probiotics strains and administration dose is important for improving colitis including UC.

Characterization of Lactic Acid Bacteria Isolated From the Gastrointestinal Tract of a Wild Boar as Potential Probiotics

Lactic acid bacteria (LAB) are major microorganisms used for probiotic purposes and prime parts of the human and mammalian gut microbiota, which exert important health-promoting effects on the host. The present study aimed to evaluate and compare the probiotic potential and safety of LAB strains isolated from the gastrointestinal tract of a wild boar from the Greater Khingan Mountains, China. Amongst all of the isolated LAB strains, five isolates identified as Lactobacillus mucosae, Lactobacillus salivarius, Enterococcus hirae, Enterococcus durans, and Enterococcus faecium, were remarkably resistant to acid and bile salt. The probiotic characteristics (including adhesion capability, antimicrobial activities, autoaggregation, and coaggregation abilities), and safety properties (including hemolytic activity, antibiotic resistance, absence/presence of virulence factors, and in vivo safety) were evaluated. The results showed that all five isolates exhibited high adhesive potential, remarkable aggregation capacity, and antibacterial activities. Upon assessment of the safety, these strains were negative for hemolytic activity and all tested virulence genes. In vivo safety assessment showed no adverse effects of isolated strains supplementation on the body weight gain and organ indices of the treated mice. This study revealed that these LAB isolates, especially L. salivarius M2-71, possess desirable probiotic properties and have great potentials for the development of feed additives for animals to promote health.

Nutritional approach as therapeutic manipulation in inflammatory bowel disease

Malnutrition is observed more frequently in patients with inflammatory bowel disease (IBD) than in the general population and associated with adverse clinical outcomes. This study aimed to review the current knowledge regarding the efficacy of dietary and nutritional intervention in IBD patients. Exclusive enteral nutrition might be inferior to corticosteroid treatment in adults with active Crohn’s disease (CD) but might even be superior considering the adverse effects of corticosteroid treatment in children. Total parenteral nutrition has no advantage over enteral nutrition, which is considered a more physiologic modality in organ function. Current guidelines do not yet recommend ω3-polyunsaturated fatty acid supplementation for the prevention and maintenance of remission in IBD patients. Dietary fiber supplementation could be effective in the relief of symptoms and maintenance of remission in ulcerative colitis (UC). Although vitamin D may be favorable to clinical course of IBD and bone density. Probiotic supplementation has proven to be effective in preventing and treating pouchitis for UC but is less effective in treating CD. Nutritional interventions not only correct nutritional deficiencies but also improve symptoms and clinical courses of the disease. Hence, nutritional approaches need to be developed to significantly evaluate the effectiveness of dietary interventions used to treat IBD.

Cecropin A Alleviates Inflammation Through Modulating the Gut Microbiota of C57BL/6 Mice With DSS-Induced IBD

The present study is undertaken to assess the alleviating effects of antimicrobial peptide cecropin A on inflammatory bowel disease (IBD) in C57BL/6 mice and changes in the gut microbiota, compared to an antibiotic gentamicin. Different doses of cecropin A were intraperitoneally injected into C57BL/6 mice for 5 days to determine the safe doses. The injection doses at ≤ 15 mg/kg showed no negative impact on the liver, heart, spleen, and kidney. The severe and moderate IBD mice model was successfully established via supplementation of 4 or 2.5% dextran sulfate sodium (DSS) in drinking water for 5 days. The severe IBD model was used to ensure the optimal therapeutic dose of cecropin A. Survival rate, body weight and disease activity index (DAI) scores were measured. Administration of 15 mg/kg, not 5 mg/kg cecropin A, for 5 days increased survival rate and decreased body weight loss of mice. The moderate IBD model was applied to investigate the mechanisms for cecropin A to alleviate inflammation in comparison to gentamicin. The mice were treated with 15 mg/kg cecropin A or 5 mg/kg gentamicin for 3 days. The levels of cytokines and related proteins in the colon were detected by ELISA and Western blotting. The microbiota in cecum contents were analyzed using 16S rRNA gene sequencing. The results showed that cecropin A and gentamicin relieved body weight loss, DAI, and gut mucosa disruption, while decreasing tumor necrosis factor-α (TNF-α), interlukin-1β (IL-1β), and interlukin-6 (IL-6) induced by DSS. In addition, cecropin A and gentamicin showed different effects on the gut microbiota structure. Both cecropin A and gentamicin decreased DSS-induced enrichment of Bacteroidaceae and Enterobacteriaceae. However, cecropin A showed a selective enrichment of Lactobacillus in contrast to gentamicin, which demonstrated a selective effect on Desulfovibrionaceae and Ruminococcaceae. Cecropin A alleviates IBD through decreasing harmful gut microflora and specifically enhancing beneficial gut microflora. The mechanism of this effect is different from gentamicin.

Probiotic Bifidobacterium lactis V9 Regulates the Secretion of Sex Hormones in Polycystic Ovary Syndrome Patients through the Gut-Brain Axis

Polycystic ovary syndrome (PCOS) is a common metabolic disorder among women of reproductive age worldwide. Through a two-phase clinical experiment, we first revealed an imbalance in the intestinal microbiome of PCOS patients. By binning and annotating shotgun metagenomic sequences into metagenomic species (MGS), 61 MGSs were identified as potential PCOS-related microbial biomarkers. In the second stage, we monitored the impact of the probiotic Bifidobacterium lactis V9 on the intestinal microbiota, metabolic parameters, gut-brain mediators, and sex hormones of PCOS patients. Notably, we observed that the PCOS-related clinical indices and the intestinal microbiotas of the participating patients exhibited an inconsistent response to the intake of the B. lactis V9 probiotic. Therefore, effective host gut colonization of the probiotic was crucial for its ability to function as a probiotic. Finally, we propose a potential mechanism by which B. lactis V9 regulates the levels of sex hormones by manipulating the intestinal microbiome in PCOS patients.

Although a few studies have investigated the intestinal microbiota of women with polycystic ovary syndrome (PCOS), the functional and metabolic mechanisms of the microbes associated with PCOS, as well as potential microbial biomarkers, have not yet been identified. To address this gap, we designed a two-phase experiment in which we performed shotgun metagenomic sequencing and monitored the metabolic parameters, gut-brain mediators, and sex hormones of PCOS patients. In the first stage, we identified an imbalance in the intestinal microbiota of the PCOS patients, observing that Faecalibacterium, Bifidobacterium, and Blautia were significantly more abundant in the control group, whereas Parabacteroides and Clostridium were enriched in the PCOS group. In the second stage, we monitored the impact of the probiotic Bifidobacterium lactis V9 on the intestinal microbiome, gut-brain mediators, and sex hormones of 14 PCOS patients. Notably, we observed that the levels of luteinizing hormone (LH) and LH/follicle-stimulating hormone (LH/FSH) decreased significantly in 9 volunteers, whereas the levels of sex hormones and intestinal short-chain fatty acids (SCFAs) increased markedly. In contrast, the changes in the indices mentioned above were indistinct in the remaining 5 volunteers. The results of an analysis of the number of viable Bifidobacterium lactis V9 cells in the two groups were highly consistent with the clinical and SCFA results. Therefore, effective host gut colonization of the probiotic Bifidobacterium lactis V9 was crucial for its ability to function as a probiotic. Finally, we propose a potential mechanism describing how probiotics regulate the levels of sex hormones by manipulating the intestinal microbiome in PCOS patients.

IMPORTANCE Polycystic ovary syndrome (PCOS) is a common metabolic disorder among women of reproductive age worldwide. Through a two-phase clinical experiment, we first revealed an imbalance in the intestinal microbiome of PCOS patients. By binning and annotating shotgun metagenomic sequences into metagenomic species (MGS), 61 MGSs were identified as potential PCOS-related microbial biomarkers. In the second stage, we monitored the impact of the probiotic Bifidobacterium lactis V9 on the intestinal microbiota, metabolic parameters, gut-brain mediators, and sex hormones of PCOS patients. Notably, we observed that the PCOS-related clinical indices and the intestinal microbiotas of the participating patients exhibited an inconsistent response to the intake of the B. lactis V9 probiotic. Therefore, effective host gut colonization of the probiotic was crucial for its ability to function as a probiotic. Finally, we propose a potential mechanism by which B. lactis V9 regulates the levels of sex hormones by manipulating the intestinal microbiome in PCOS patients.

Bifidobacterium longum and VSL#3® amelioration of TNBS-induced colitis associated with reduced HMGB1 and epithelial barrier impairment

Probiotics are a beneficial treatment for inflammatory bowel disease (IBD). However, studies comparing the effects of similar doses of single and mixed probiotics on IBD are scarce. High mobility group box 1 (HMGB1) is an important proinflammatory mediator involved IBD development. The present study assessed fecal HMGB1 levels in IBD patients and compared the effects of similar doses of Bifidobacterium longum (Bif) versus VSL#3^® on HMGB1 levels in 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced murine colitis. Twenty-four mice were divided into four treatment groups (n = 6 per group): ethanol (control), TNBS, TNBS + Bif, and TNBS + VSL#3^®. Bif and VSL#3^® (4 × 10⁹ CFU/dose) were administered daily by intragastric gavage, beginning 3 d before TNBS treatment, for a total of 7 d. Fecal HMGB1 levels were higher in both active IBD patients and TNBS-induced colitis mice versus their respective controls. Both Bif and VSL#3^® improved intestinal inflammation and fecal microbiota imbalance in TNBS-induced colitis mice. Both treatments also reduced serum and fecal HMGB1 levels as well as increased expression of zonula occludins-1, occludin, and claudin-1 in colon tissues. In Caco-2 cells, HMGB1 reduced transepithelial electrical resistance, zonula occludins-1 protein expression, and increased paracellular permeability of FITC-dextran; the opposite was found with both probiotic treatments. These findings suggest Bif and VSL#3^® have similar beneficial effects on TNBS-induced colitis, possibly through inhibition of HMGB1 release and subsequent HMGB1-mediated gut barrier dysfunction. The present study provides novel insights into probiotic treatment of IBD.

Bacillus amyloliquefaciens Ameliorates Dextran Sulfate Sodium-Induced Colitis by Improving Gut Microbial Dysbiosis in Mice Model

Several Bacillus strains exert beneficial effects on the maintenance of intestinal homeostasis and host health. However, whether Bacillus amyloliquefaciens (BA) can improve gut microbial dysbiosis and ameliorate colitis is unknown. Therefore, we conducted the present study to investigate the effects of BA administration on intestinal morphology, inflammatory response, and colonic microbial composition in a mouse model of dextran sulfate sodium (DSS)-induced colitis. Results showed that BA administration significantly ameliorated body weight loss, decreased disease activity index, and improved colonic tissue morphology in DSS-treated mice. In addition, levels of immunoglobulins, as well as pro-inflammatory cytokines, were decreased after BA administration. Importantly, colonic microbiota profiling indicated a significant (p < 0.05) difference in beta-diversity between BA-administrated and DSS-treated mice, according to weighted principal coordinate analysis (PCoA) results. The relative abundance of the Firmicutes genus was increased, whereas that of Bacteroidetes was decreased by BA administration. Furthermore, phylogenetic investigation of communities by reconstruction of unobserved states (PICRUSt) analysis showed that the most significantly changed pathways between the four groups of mice were carbohydrate, lipid, and amino acid metabolism. In conclusion, our results showed that BA administration has beneficial effects on DSS-induced colitis, suggesting that this strategy might be useful for the treatment of dysbiosis during ulcerative colitis. Further, the changes in metabolism, especially amino acid metabolism, might contribute to the beneficial effects of BA on the amelioration of DSS-induced colitis.

Protective effects of a novel probiotic strain, Lactococcus lactis ML2018, in colitis: in vivo and in vitro evidence

Multiple articles have confirmed that an imbalance of the intestinal microbiota is closely related to aberrant immune responses of the intestines and to the pathogenesis of inflammatory bowel diseases (IBDs).

Intestinal barrier dysfunction orchestrates the onset of inflammatory host-microbiome cross-talk in a human gut inflammation-on-a-chip

The initiation of intestinal inflammation involves complex intercellular cross-talk of inflammatory cells, including the epithelial and immune cells, and the gut microbiome. This multicellular complexity has hampered the identification of the trigger that orchestrates the onset of intestinal inflammation. To identify the initiator of inflammatory host-microbiome cross-talk, we leveraged a pathomimetic "gut inflammation-on-a-chip" undergoing physiological flow and motions that recapitulates the pathophysiology of dextran sodium sulfate (DSS)-induced inflammation in murine models. DSS treatment significantly impaired, without cytotoxic damage, epithelial barrier integrity, villous microarchitecture, and mucus production, which were rapidly recovered after cessation of DSS treatment. We found that the direct contact of DSS-sensitized epithelium and immune cells elevates oxidative stress, in which the luminal microbial stimulation elicited the production of inflammatory cytokines and immune cell recruitment. In contrast, an intact intestinal barrier successfully suppressed oxidative stress and inflammatory cytokine production against the physiological level of lipopolysaccharide or nonpathogenic Escherichia coli in the presence of immune elements. Probiotic treatment effectively reduced the oxidative stress, but it failed to ameliorate the epithelial barrier dysfunction and proinflammatory response when the probiotic administration happened after the DSS-induced barrier disruption. Maintenance of epithelial barrier function was necessary and sufficient to control the physiological oxidative stress and proinflammatory cascades, suggesting that "good fences make good neighbors." Thus, the modular gut inflammation-on-a-chip identifies the mechanistic contribution of barrier dysfunction mediated by intercellular host-microbiome cross-talk to the onset of intestinal inflammation.

Review article: the evidence that vancomycin is a therapeutic option for primary sclerosing cholangitis

BACKGROUND AND AIMS

PSC is an autoimmune biliary inflammatory disorder that is often associated with inflammatory bowel disease (IBD), with 50%-75% of patients with PSC having coexisting IBD, most commonly ulcerative colitis. Currently, no medical therapies have been shown to improve the disease course or slow its progression. However, ongoing research has resulted in a growing interest in the use of antibiotics for treatment of PSC, of which vancomycin is the most studied. In this review, we summarise the current evidence on the use of vancomycin in PSC and comment on future research areas of interest.

METHODS

A comprehensive PUBMED and EMBASE literature search for articles on vancomycin, PSC, therapeutic options and microbiome was performed.

RESULTS

Two randomised clinical trials, three case series and two case reports were included in the study. These include uncontrolled data from at least 98 patients that include promising improvements in biochemistry and imaging. Optimal dosing regimens are unclear.

CONCLUSION

Vancomycin is one of the most studied antibiotics used in the treatment of PSC with promising results. There is not currently sufficient evidence to support treatment recommendations. Further research is needed to establish if vancomycin is a PSC treatment.

Iron Supplements Modulate Colon Microbiota Composition and Potentiate the Protective Effects of Probiotics in Dextran Sodium Sulfate-induced Colitis

BACKGROUND

Iron is an important nutrient for both the host and colonizing bacteria. Oral iron supplementation may impact the composition of the microbiota and can be particularly damaging to patients suffering from inflammatory bowel disease (IBD). However, patients with IBD may require iron supplementation to treat their anemia.

METHODS

We fed mice with diets supplemented with ferrous sulfate at different doses (5, 50, and 500 mg of iron/kg chow) and with different iron formulations (ferrous sulfate, ferrous bisglycinate and ferric ethylenediaminetetraacetic acid [FEDTA]), and analyzed the effects on the composition of the gut microbiota by 16S ribosomal RNA gene sequencing. Using the dextran sodium sulfate (DSS)-induced colitis mouse model, we investigated the effects of iron supplementation in colitis severity, as well as the use of the probiotic Escherichia coli Nissle 1917 (EcN) in combination with iron supplementation.

RESULTS

Iron supplementation at different doses induced shifts in the gut microbial communities and inferred metabolic pathways. However, depending on the iron formulation used in the diets, iron supplementation during dextran sodium sulfate-induced colitis was either beneficial (ferrous bisglycinate) or highly detrimental (FEDTA). Finally, the beneficial effect of the probiotic EcN in the dextran sodium sulfate-induced colitis model was potentiated by oral iron supplementation with ferrous sulfate.

CONCLUSIONS

These results show that the iron formulations used to treat iron deficiency influence the gut microbiota and colitis in mice and suggest that distinct iron compounds may be of particular relevance to patients with IBD. In addition, the beneficial action of probiotics in IBD may be enhanced by oral iron supplementation.

Probiotic Bacillus amyloliquefaciens SC06 Induces Autophagy to Protect against Pathogens in Macrophages

Probiotics are increasingly applied in popularity in both humans and animals. Decades of research has revealed their beneficial effects, including the immune modulation in intestinal pathogens inhibition. Autophagy—a cellular process that involves the delivery of cytoplasmic proteins and organelles to the lysosome for degradation and recirculation—is essential to protect cells against bacterial pathogens. However, the mechanism of probiotics-mediated autophagy and its role in the elimination of pathogens are still unknown. Here, we evaluated Bacillus amyloliquefaciens SC06 (Ba)-induced autophagy and its antibacterial activity against Escherichia coli (E. coli) in murine macrophage cell line RAW264.7 cells. Western blotting and confocal laser scanning analysis showed that Ba activated autophagy in a dose- and time-dependent manner. Ba-induced autophagy was found to play a role in the elimination of intracellular bacteria when RAW264.7 cells were challenged with E. coli. Ba induced autophagy by increasing the expression of Beclin1 and Atg5-Atg12-Atg16 complex, but not the AKT/mTOR signaling pathway. Moreover, Ba pretreatment attenuated the activation of JNK in RAW264.7 cells during E. coli infection, further indicating a protective role for probiotics via modulating macrophage immunity. The above findings highlight a novel mechanism underlying the antibacterial activity of probiotics. This study enriches the current knowledge on probiotics-mediated autophagy, and provides a new perspective on the prevention of bacterial infection in intestine, which further the application of probiotics in food products.

ZnO nanoparticles act as supportive therapy in DSS-induced ulcerative colitis in mice by maintaining gut homeostasis and activating Nrf2 signaling

Inflammatory bowel diseases (IBD) are widespread inflammatory diseases that cause debilitating health problems including cancer. In this study, we show that ZnO nanoparticle (ZnONP) treatment has markedly dose-dependent effects on the remission of dextran sulfate sodium (DSS)-induced ulcerative colitis in mice. We demonstrate the mechanism involves the antioxidant and anti-inflammatory abilities of ZnONPs to suppress ROS and malondialdehyde (MDA) production; increase GSH level; suppress proinflammatory cytokines IL-1β and TNF-α and myeloperoxidase (MPO). The ZnONP treatment is able to activate the Nrf2 pathway in the cellular antioxidant defense system. The novel finding is that ZnONP combined with mesalazine (5-ASA) can enhance the therapeutic efficacy of 5-ASA in the treatment of DSS-induced colitis. Lastly, we found that ZnONP treatment can restore the changes in special colonic bacteria of DSS-mice while the drug 5-ASA cannot. These results indicate that ZnONPs can act as a medical additive for the therapy of IBD.

THE INTESTINAL MICROBIOTA AND THE ROLE OF PROBIOTICS IN IRRITABLE BOWEL SYNDROME: a review

Irritable bowel syndrome is a common, chronic relapsing gastrointestinal disorder that affects 7%-22% of the population worldwide. According to Rome III Criteria, the disorder is defined by the coexistence of abdominal discomfort or pain associated with an alteration in bowel habits. Its pathophysiology is not completely understood but, in addition to some important abnormalities, the disturbed intestinal microbiota has also been described supported by several strands of evidence. The treatment of irritable bowel syndrome is based upon several therapeutic approaches but few have been successful or without adverse events and more recently the gut microbiota and the use of probiotics have emerged as a factor to be considered. Probiotics are live micro-organisms which when consumed in adequate amounts confer a health benefit to the host, such as Lactic bacteria among others. An important scientific rationale has emerged for the use of probiotics in irritable bowel syndrome, although the data regarding different species are still limited. Not all probiotics are beneficial: it is important to select the specific strain which should be supported by good evidence base. The mechanisms of action of probiotics are described and the main strains are quoted.

Diet therapy for inflammatory bowel diseases: The established and the new

Although patients with inflammatory bowel diseases (IBD) have a strong interest in dietary modifications as part of their therapeutic management, dietary advice plays only a minor part in published guidelines. The scientific literature shows that dietary factors might influence the risk of developing IBD, that dysbiosis induced by nutrition contributes to the pathogenesis of IBD, and that diet may serve as a symptomatic treatment for irritable bowel syndrome-like symptoms in IBD. The role of nutrition in IBD is underscored by the effect of various dietary therapies. In paediatric patients with Crohn’s disease (CD) enteral nutrition (EN) reaches remission rates similar to steroids. In adult patients, however, EN is inferior to corticosteroids. EN is not effective in ulcerative colitis (UC). Total parenteral nutrition in IBD is not superior to steroids or EN. The use of specific probiotics in patients with IBD can be recommended only in special clinical situations. There is no evidence for efficacy of probiotics in CD. By contrast, studies in UC have shown a beneficial effect in selected patients. For patients with pouchitis, antibiotic treatment followed by probiotics, like VSL#3 or Lactobacillus GG, is effective. When probiotics are used, the risk of bacterial translocation and subsequent bacteremia has to be considered. More understanding of the normal intestinal microflora, and better characterization of probiotic strains at the phenotypic and genomic levels is needed as well as clarification of the mechanisms of action in different clinical settings. A FODMAP reduced diet may improve symptoms in IBD.

Activation of Natural Killer Cells by Probiotics

During the last decade, probiotics have been established to be important mediators of host immunity. Their effects on both innate and adaptive immunity have been documented in the literature. Although several reports have correlated different strains of bacteria as probiotics, their effects on immunity vary. Clearly, there is a complex interplay between various constituents of probiotics and the immune response in humans. The role of probiotics on natural killer (NK) cells in the gut has been the subject of a few reports. In this review, we summarize the reported findings on the role of probiotics in the activation of gut-associated NK cells and the response of NK cells to stimuli elicited by probiotics and their microenvironment. The effects of probiotics on the activation of NK cells and their secretion of immune factors (e.g., interferon-γ, tumor necrosis factor-α, interleukin-2, etc.) are discussed in regard to their clinical significance in various diseases. Current investigations are being pursued, in particular, on the role of probiotics-activated NK cells in promoting the adaptive immune response against pathogens.

Allogeneic guinea pig mesenchymal stem cells ameliorate neurological changes in experimental colitis

Background

The use of mesenchymal stem cells (MSCs) to treat inflammatory bowel disease (IBD) is of great interest because of their immunomodulatory properties. Damage to the enteric nervous system (ENS) is implicated in IBD pathophysiology and disease progression. The most commonly used model to study inflammation-induced changes to the ENS is 2,4,6-trinitrobenzene-sulfonate acid (TNBS)-induced colitis in guinea pigs; however, no studies using guinea pig MSCs in colitis have been performed. This study aims to isolate and characterise guinea pig MSCs and then test their therapeutic potential for the treatment of enteric neuropathy associated with intestinal inflammation.

Methods

MSCs from guinea pig bone marrow and adipose tissue were isolated and characterised in vitro. In in vivo experiments, guinea pigs received either TNBS for the induction of colitis or sham treatment by enema. MSCs were administered at a dose of 1 × 10⁶ cells via enema 3 h after the induction of colitis. Colon tissues were collected 24 and 72 h after TNBS administration to assess the level of inflammation and damage to the ENS. The secretion of transforming growth factor-β1 (TGF-β1) was analysed in MSC conditioned medium by flow cytometry.

Results

Cells isolated from both sources were adherent to plastic, multipotent and expressed some human MSC surface markers. In vitro characterisation revealed distinct differences in growth kinetics, clonogenicity and cell morphology between MSC types. In an in vivo model of TNBS-induced colitis, guinea pig bone marrow MSCs were comparatively more efficacious than adipose tissue MSCs in attenuating weight loss, colonic tissue damage and leukocyte infiltration into the mucosa and myenteric plexus. MSCs from both sources were equally neuroprotective in the amelioration of enteric neuronal loss and changes to the neurochemical coding of neuronal subpopulations. MSCs from both sources secreted TGF-β1 which exerted neuroprotective effects in vitro.

Conclusions

This study is the first evaluating the functional capacity of guinea pig bone marrow and adipose tissue-derived MSCs and providing evidence of their neuroprotective value in an animal model of colitis. In vitro characteristics of MSCs cannot be extrapolated to their therapeutic efficacy. TGF-β1 released by both types of MSCs might have contributed to the attenuation of enteric neuropathy associated with colitis.

Surface protein Esp enhances pro-inflammatory cytokine expression through NF-κB activation during enterococcal infection

Enterococcal surface protein (Esp) is encoded on a pathogenicity island in Enterococcus faecalis and E. faecium and is involved in biofilm formation and binding to epithelial cells. In this study, using Esp-expressing E. faecalis MMH594 and its isogenic Esp-deficient strain, as well as purified Esp, we show that Esp is sufficient for activation of NF-κB and the subsequent production of pro-inflammatory cytokines IL-1β and TNF-α in macrophages in vitro. In a mouse peritonitis model, we also show that mice infected with Esp-expressing E. faecalis showed comparatively higher levels of cytokines TNF-α, IL-1β and IL-6 in peritoneal fluid, and IL-6 in serum. Moreover, neutrophil infiltration and tissue damage in the liver was higher in the mice infected with the Esp-expressing strain compared with mice infected with the Esp-deficient mutant. These results add Esp to the growing list of enterococcal virulence factors that can modulate inflammation during infection and has implications for enterococcal pathogenesis.

Why is initial bacterial colonization of the intestine important to infants' and children's health?

Microbial colonization of the infant occurs during a critical time window for immune and gastrointestinal development. Infant colonization sets the stage for the adult microbiome. This review is a broad survey of the factors affecting infant colonization and the downstream effects on gastrointestinal health and disease. Major topics affecting colonization include initial inoculation dependent on birth mode, the impact of breast-feeding, and inside-out modulation of the developing microbiome by the immune system. Major outcomes of colonization include the timing-dependent education of the neonatal immune system, which is interconnected with barrier function and metabolism. These all engage in further continuing cross-talk with the microbiome, genetics, and nutrition. This review also briefly examines mechanisms of disease resulting from disrupted colonization as well as nutritional and microbial therapies.

Live Combined Bacillus subtilis and Enterococcus faecium Ameliorate Murine Experimental Colitis by Immunosuppression

Live combined Bacillus subtilis and Enterococcus faecium ameliorate murine experimental colitis by immunosuppression manifested by downregulation of TLRs, macrophages, Th1, and Th2 but upregulation of Tregs.

The gut microbiota in mouse models of inflammatory bowel disease

The intestine and the intestinal immune system have evolved through a symbiotic homeostasis under which a highly diverse microbial flora is maintained in the gastrointestinal tract while pathogenic bacteria are recognized and eliminated. Disruption of the balance between the immune system and the gut microbiota results in the development of multiple pathologies in humans. Inflammatory bowel diseases (IBD) have been associated with alterations in the composition of intestinal flora but whether these changes are causal or result of inflammation is still under dispute. Various chemical and genetic models of IBD have been developed and utilized to elucidate the complex relationship between intestinal epithelium, immune system and the gut microbiota. In this review we describe some of the most commonly used mouse models of colitis and Crohn's disease (CD) and summarize the current knowledge of how changes in microbiota composition may affect intestinal disease pathogenesis. The pursuit of gut-microbiota interactions will no doubt continue to provide invaluable insight into the complex biology of IBD.

VSL#3 probiotic modifies mucosal microbial composition but does not reduce colitis-associated colorectal cancer

Although probiotics have shown success in preventing the development of experimental colitis-associated colorectal cancer (CRC), beneficial effects of interventional treatment are relatively unknown. Here we show that interventional treatment with VSL#3 probiotic alters the luminal and mucosally-adherent microbiota, but does not protect against inflammation or tumorigenesis in the azoxymethane (AOM)/Il10⁻/⁻ mouse model of colitis-associated CRC. VSL#3 (10⁹ CFU/animal/day) significantly enhanced tumor penetrance, multiplicity, histologic dysplasia scores, and adenocarcinoma invasion relative to VSL#3-untreated mice. Illumina 16S sequencing demonstrated that VSL#3 significantly decreased (16-fold) the abundance of a bacterial taxon assigned to genus Clostridium in the mucosally-adherent microbiota. Mediation analysis by linear models suggested that this taxon was a contributing factor to increased tumorigenesis in VSL#3-fed mice. We conclude that VSL#3 interventional therapy can alter microbial community composition and enhance tumorigenesis in the AOM/Il10⁻/⁻ model.

Vitamin D regulates the gut microbiome and protects mice from dextran sodium sulfate-induced colitis

The active form of vitamin D [1,25-dihydroxycholecalciferol, 1,25(OH)2D3] and the vitamin D receptor (VDR) regulate susceptibility to experimental colitis. The effect of the bacterial microflora on the susceptibility of C57BL/6 mice to dextran sodium sulfate-induced colitis was determined. Mice that cannot produce 1,25(OH)2D3 [Cyp27b1 (Cyp) knockout (KO)], VDR KO as well as their wild-type littermates were used. Cyp KO and VDR KO mice had more bacteria from the Bacteroidetes and Proteobacteria phyla and fewer bacteria from the Firmicutes and Deferribacteres phyla in the feces compared with wild-type. In particular, there were more beneficial bacteria, including the Lactobacillaceae and Lachnospiraceae families, in feces from Cyp KO and VDR KO mice than in feces from wild-type. Helicobacteraceae family member numbers were elevated in Cyp KO compared with wild-type mice. Depletion of the gut bacterial flora using antibiotics protected mice from colitis. 1,25(OH)2D3 treatment (1.25 μg/100 g diet) of Cyp KO mice decreased colitis severity and reduced the numbers of Helicobacteraceae in the feces compared with the numbers in the feces of untreated Cyp KO mice. The mechanisms by which the dysbiosis occurs in VDR KO and Cyp KO mice included lower expression of E-cadherin on gut epithelial and immune cells and fewer tolerogenic dendritic cells that resulted in more gut inflammation in VDR and Cyp KO mice compared with wild-type mice. Increased host inflammation has been shown to provide pathogens with substrates to out-compete more beneficial bacterial species. Our data demonstrate that vitamin D regulates the gut microbiome and that 1,25(OH)2D3 or VDR deficiency results in dysbiosis, leading to greater susceptibility to injury in the gut.

Intestinal microbiota, diet and health

The human intestine is colonised by 10¹³ to 10¹⁴ micro-organisms, the vast majority of which belong to the phyla Firmicutes and Bacteroidetes. Although highly stable over time, the composition and activities of the microbiota may be influenced by a number of factors including age, diet and antibiotic treatment. Although perturbations in the composition or functions of the microbiota are linked to inflammatory and metabolic disorders (e.g. inflammatory bowel diseases, irritable bowel syndrome and obesity), it is unclear at this point whether these changes are a symptom of the disease or a contributing factor. A better knowledge of the mechanisms through which changes in microbiota composition (dysbiosis) promote disease states is needed to improve our understanding of the causal relationship between the gut microbiota and disease. While evidence of the preventive and therapeutic effects of probiotic strains on diarrhoeal illness and other intestinal conditions is promising, the exact mechanisms of the beneficial effects are not fully understood. Recent studies have raised the question of whether non-viable probiotic strains can confer health benefits on the host by influencing the immune system. As the potential health effect of these non-viable bacteria depends on whether the mechanism of this effect is dependent on viability, future research needs to consider each probiotic strain on a case-by-case basis. The present review provides a comprehensive, updated overview of the human gut microbiota, the factors influencing its composition and the role of probiotics as a therapeutic modality in the treatment and prevention of diseases and/or restoration of human health.

Gram-negative bacteria account for main differences between faecal microbiota from patients with ulcerative colitis and healthy controls

Detailed knowledge about the composition of the intestinal microbiota may be critical to unravel the pathogenesis of ulcerative colitis (UC), a human chronic inflammatory bowel disease, since the intestinal microbes are expected to influence some of the key mechanisms involved in the inflammatory process of the gut mucosa. The aim of this study was to investigate the faecal microbiota in patients either with UC in remission (n=6) or with active disease (n=6), and in healthy controls (n=6). The composition of Gram-negative bacteria and Gram-positive bacteria was examined. Antigenic structures of Gram-negative bacteria such as lipopolysaccharides have been related to the inflammatory responses and pathogenesis of inflammatory bowel disease. Dice cluster analysis and principal component analysis of faecal microbiota profiles obtained by denaturing gradient gel electrophoresis and quantitative PCR, respectively, revealed that the composition of faecal bacteria from UC patients with active disease differed from the healthy controls and that this difference should be ascribed to Gram-negative bacteria. The analysis did not show any clear grouping of UC patients in remission. Even with the relatively low number of subjects in each group, we were able to detect a statistically significant underrepresentation of Lactobacillus spp. and Akkermansia muciniphila in UC patients with clinically active disease compared to the healthy controls. In line with previous communications, we have shown that the microbiota in UC patients with active disease differ from that in healthy controls. Our findings indicate that alterations in the composition of the Gram-negative bacterial population, as well as reduced numbers of lactobacilli and A. muciniphila may play a role in UC.

Intestinal dendritic cells: their role in intestinal inflammation, manipulation by the gut microbiota and differences between mice and men

The intestinal immune system maintains a delicate balance between immunogenicity against invading pathogens and tolerance of the commensal microbiota and food antigens. Dendritic cells (DC) generate primary T-cell responses, and determine whether these responses are immunogenic or tolerogenic. The regulatory role of DC is of particular importance in the gut due to the high antigenic load. Intestinal DC act as sentinels, sampling potentially pathogenic antigens but also harmless antigens including the commensal microbiota. Following antigen acquisition, intestinal DC migrate to secondary lymphoid organs to activate naive T-cells. DC also imprint specific homing properties on T-cells that they stimulate; gut DC specifically induce gut-homing properties on T-cells upon activation, enabling T-cell migration back to intestinal sites. Data regarding properties on gut DC in humans is scarce, although evidence now supports the role of DC as important players in intestinal immunity in humans. Here, we review the role of intestinal DC in shaping mucosal immune responses and directing tissue-specific T-cell responses, with a special focus on the importance of distinguishing DC subsets from macrophages at intestinal sites. We compare and contrast human DC with their murine counterparts, and discuss the ability of the gut microbiota to shape intestinal DC function, and how this may be dysregulated in inflammatory bowel disease (IBD). Lastly, we describe recent advances in the study of probiotics on intestinal DC function, including the use of soluble secreted bacterial products.

Probiotics, prebiotics, synbiotics: is there enough evidence to support their use in colorectal cancer surgery?

BACKGROUND/AIMS

Pro-/pre-/synbiotics supplementation seems to provide beneficial effects in various aspects of abdominal pathology. Skepticism exists with respect to their effects on colorectal cancer (CRC) patients. This review presents the potential clinical applications of pro-/pre-/synbiotics in CRC surgery.

METHODS

A literature search of electronic databases was conducted and all studies published on 'probiotics', 'prebiotics' and 'synbiotics' were collected. Among them, the ones referring to CRC and which had any clinical relevance offering information on perioperative parameters were used.

RESULTS

Incorporation of pre-/pro-/synbiotic formulations in the preoperative mechanical bowel preparation cannot be supported by the current evidence. Limited clinical studies may be promising in supporting their potentially protective role against postoperative infectious complications. Encouraging are the results on their protective role against adjuvant (chemo)radiation-induced diarrhea. Such supplementation may also hold promise to improve postcolectomy gastrointestinal related quality of life.

CONCLUSIONS

Despite the positive results and plethora of agents, bacterial combinations and concentrations, the inconsistency in administration, the inhomogeneity of comparison groups and lack of stringent clinical endpoints remain obstacles in the effort to establish a definitive clinical strategy at this time. Further work is warranted to gain a keen understanding of their clinical value in CRC patients.

Microbiome and immunological interactions

The healthy human gut supports a complex and diverse microbiota, dominated by bacterial phylotypes belonging to Bacteroidetes and Firmicutes. In the inflamed gut, overall diversity decreases, coincident with a greater representation of Proteobacteria. There is growing evidence supporting an important role for human gut bacteria in mucosal immunity; interactions at the level of both intestinal and colonic epithelial cells, dendritic cells, and T and B immune cells have been documented. These interactions influence gut barrier and defense mechanisms that include antimicrobial peptide and secretory IgA synthesis. The functional effects of commensal bacteria on T helper cell differentiation have led to the emerging concept that microbiota composition determines T effector- and T regulatory-cell balance, immune responsiveness, and homeostasis. The importance of this biology in relation to immune homeostasis, inflammatory bowel disease, and the rising incidence of autoimmune diseases will be discussed. The detailed description of the human gut microbiota, integrated with evidence-based mechanisms of immune modulation, provides an exciting platform for the identification of next-generation probiotics and related pharmaceutical products.

Microbiota-targeted therapies: an ecological perspective

The connection between disease and the disruption of homeostatic interactions between the host and its microbiota is now well established. Drug developers and clinicians are starting to rely more heavily on therapies that directly target the microbiota and on the ecology of the microbiota to understand the outcomes of these treatments. The effects of those microbiota-targeted therapies that alter community composition range in scale from eliminating individual strains of a single species (for example, with antibacterial conjugate vaccines) to replacing the entire community with a new intact microbiota (for example, by fecal transplantation). Secondary infections linked to antibiotic use provide a cautionary tale of the unintended consequences of perturbing a microbial species network and highlight the need for new narrow-spectrum antibiotics with rapid companion diagnostics. Insights into microbial ecology will also benefit the development of probiotics, whose therapeutic prospects will depend on rigorous clinical testing. Future probiotics may take the form of a consortium of long-term community residents: "a fecal transplant in a capsule." The efficacy of microbiota-targeted therapies will need to be assessed using new diagnostic tools that measure community function rather than composition, including the temporal response of a microbial community to a defined perturbation such as an antibiotic or probiotic.

Gene expression profiling identifies mechanisms of protection to recurrent trinitrobenzene sulfonic acid colitis mediated by probiotics

BACKGROUND

Host-microbiota interactions in the intestinal mucosa play a major role in intestinal immune homeostasis and control the threshold of local inflammation. The aim of this study was to evaluate the efficacy of probiotics in the recurrent trinitrobenzene sulfonic acid (TNBS)-induced colitis model and gain more insight into protective mechanisms.

METHODS

Moderate chronic inflammation of the colon was induced in BALB/c mice by repetitive intrarectal challenges with TNBS. Administration of probiotics started 2 weeks before colitis induction and was continued throughout colitis development.

RESULTS

Long-term administration of Lactobacillus plantarum NCIMB8826 or the probiotic mixture VSL#3 reduced intestinal inflammation induced by TNBS, evident from improved colon morphology and less influx of innate (CD11b(+) ) and adaptive (CD4(+) /CD8(+) ) immune cells in the intestinal mucosa and decreased proinflammatory serum cytokines (interferon-gamma [IFN-γ], interleukin [IL]-17, IL-1β, monocyte chemoattractant protein [MCP]-1) in probiotic-treated mice. Genomewide expression analysis of colonic tissues using microarrays revealed differences in expression of genes related to inflammation and immune processes between untreated and probiotic treated mice. Principal component analysis revealed that probiotic treatment resulted in a shift of gene expression profiles toward those of healthy controls. Effects of probiotics on colonic gene expression were most profound during active inflammation, in particular on gene clusters related to mast cells and antimicrobial peptides. The results were substantiated by suppression of chemokine gene expression.

CONCLUSIONS

Our data are in favor of a model in which probiotics downregulate expression of chemokines in the colon, thereby decreasing influx of inflammatory cells and rendering mice resistant to the induction of colitis.

Protective effects of cathelicidin-encoding Lactococcus lactis in murine ulcerative colitis

BACKGROUND AND AIM

Intrarectal administration of mouse cathelin-related antimicrobial peptide (mCRAMP) reduced intestinal inflammation in mice. In the current study, we examined whether mCRAMP-transformed Lactococcus lactis given orally attained similar protective effects.

METHOD

mCRAMP was produced and secreted from the transformed L. lactis. Murine colitis was induced by ingestion of 3% dextran sulfate sodium (DSS) for 7 days. Eight or 10 log colony forming unit (cfu) L. lactis or the transformed strains with or without nisin induction were given orally as a parallel treatment with DSS. The body weight, fecal microbiota populations, clinical symptoms and histological examinations of colonic tissues were determined. Myeloperoxidase (MPO) activity and malondialdehyde (MDA) level were also evaluated to reflect the degree of inflammation. A prototype anti-inflammatory drug sulfasalazine was used as a reference drug to compare the efficacy and mechanisms of action for ulcerative colitis (UC).

RESULT

Compared with the control group with colitis, cathelicidin-transformed L. lactis could improve the clinical symptoms, maintain crypt integrity and preserve mucus content (P < 0.01). The number of apoptotic cells, MPO activity and MDA level were also significantly reduced (P < 0.05). The increases of fecal microbiota in colitis animals were markedly prevented (P < 0.001). Unlike mCRAMP-encoding L. lactis, effective doses of sulfasalazine only alleviated the clinical symptoms (P < 0.01) but not the mucosal damage in the colon.

CONCLUSION

mCRAMP-transformed L. lactis has been shown to produce mCRAMP, effectively preventing murine UC. Oral administration of this biological preparation is better than sulfasalazine for the treatment of UC.

Successful treatment of primary sclerosing cholangitis with a steroid and a probiotic

Primary sclerosing cholangitis (PSC) is a serious disease that not only affects quality of life but can also have a significant effect on patient survival. The treatment for PSC is primarily supportive with the aim of controlling cholestatic symptoms and preventing complications. Ursodeoxycholic acid may induce biochemical improvements in affected patients; however, long-term pediatric studies to determine its possible benefits in young patients are lacking. Thus, the treatment of pediatric PSC remains a significant clinical challenge. We describe a patient with PSC and undetermined colitis who was treated with a combination of a steroid, salazosulfapyridine, and a probiotic. This treatment provided benefits both for PSC and the undetermined colitis. These findings suggest that bacterial flora and gut inflammation are closely associated with the pathogenesis of inflammatory bowel disease-related PSC. Suppression of bowel inflammation and maintenance of bacterial homeostasis may be important for treating PSC.

Anti-alpha-Gal antibody titres remain unaffected by the consumption of fermented milk containing Lactobacillus casei in healthy adults

Alpha-Gal is a glycoconjugate present on cell membranes of non-primate mammals and bacteria, but not in humans, who display anti-Gal antibodies (ABs) in high titres. Probiotics contain bacterial strains which colonize the intestinal tract. In the present study, we investigated whether intake of fermented milk containing Lactobacillus casei (FML) affects anti-Gal AB titres. Serum was drawn from healthy probands (n = 19) for 6 weeks. After the second week, the probands consumed 125 ml of FML per day. Anti-Gal ABs of all isotypes and cytokines were measured. Bacterial cultures were bred from FML and bacteria were stained for alpha-Gal. Concentration of bacteria in FML was manifold higher than in conventional yoghurt (2 × 10(5)/g yoghurt vs. 1.1 × 10(7)/g FML). Both stained highly positive for Alpha-Gal. Alpha-Gal-specific ABs and cytokines remained unaffected by FML intake. Our results indicated that the consumption of FML does not elicit a humoral immune response in healthy adults.

Lessons from probiotic-host interaction studies in murine models of experimental colitis

In inflammatory bowel diseases (IBD), it is known that besides genetic and environmental factors (e.g. diet, drugs, stress), the microbiota play an important role in the pathogenesis. Patients with IBD have an altered microbiota (dysbiosis) and therefore, probiotics, defined as 'live micro-organisms that when administered in adequate amounts can confer a health benefit on the host', have been suggested as nutritional supplements to restore these imbalances. The best response on probiotics among the different types of IBD appears to be in the case of ulcerative colitis. Although probiotics show promise in IBD in both clinical and animal studies, further mechanistic studies are necessary to optimize the use of probiotics as supporting therapy in IBD. Murine models of experimental colitis have been used for decades to study this pathology, and these models have been proven useful to search for new therapeutic approaches. The purpose of this review is to summarize probiotic-host interaction studies in murine models of experimental colitis and to evaluate how these models can further help in understanding these complex interactions. Unraveling the molecular mechanisms behind the beneficial effects will assist in better and possibly more efficient probiotic formulations.

Nutrition modulation of gastrointestinal toxicity related to cancer chemotherapy: from preclinical findings to clinical strategy

Chemotherapy-induced gut toxicity is a major dose-limiting toxicity for many anticancer drugs. Gastrointestinal (GI) complications compromise the efficacy of chemotherapy, promote overall malnutrition, aggravate cancer cachexia, and may contribute to worsened prognosis. The GI tract is an attractive target for nutrition modulation, owing to its direct exposure to the diet, participation in uptake and metabolism of nutrients, high rate of cell turnover, and plasticity to nutrition stimuli. Glutamine, ω-3 polyunsaturated fatty acids, and probiotics/prebiotics are therapeutic factors that potentially modulate GI toxicity related to cancer treatments. Preclinical and clinical evidence are reviewed to critically define plausible benefits of these factors and their potential development into adjuncts to cancer chemotherapy. Mechanisms underlying the action of these nutrients are being unraveled in the laboratory. Optimal strategies to translate these findings into clinical care still remain to be elucidated. Key questions that remain to be answered include the following: which nutrient or combination of nutrients is selected for which patient and chemotherapy regimen? What mechanisms are responsible for modulation, and how are nutrient(s) administered in a clinically optimal manner? Research exploring interactions between different nutrients in GI protection is ongoing and demands further understanding. How nutrition preparations given to chemotherapy-treated patients are formulated in terms of component selection and dose optimization should be carefully studied and justified.

[Recent advances in Saccharomyces boulardii research]

This review summarizes the probiotic mechanisms of action of Saccharomyces boulardii (S. boulardii) against inflammatory and non-inflammatory diarrheal conditions. S. boulardii is distributed in lyophilized form in many countries and used for the prevention of diarrhea in children and adults, including Clostridium difficile (C. difficile) associated infection. The main mechanisms of action of S. boulardii include inhibition of activities of bacterial pathogenic products, trophic effects on the intestinal mucosa, as well as modification of host signaling pathways involved in inflammatory and non-inflammatory intestinal diseases. S. boulardii inhibits production of pro-inflammatory cytokines by inhibiting main regulators of inflammation, including nuclear factor κB (NF-κB), and mitogen-activated protein kinases (MAP kinases), ERK1/2 and p38, but stimulates production of anti-inflammatory molecules such as peroxisome proliferator-activated receptor-gamma (PPAR-γ). Moreover, S. boulardii suppresses bacterial infection by inhibiting adhesion and/or overgrowth of bacteria, produces a serine protease that cleaves C. difficile toxin A, and stimulates antibody production against this toxin. Furthermore, S. boulardii may interfere with pathogenesis of Inflammatory Bowel Disease (IBD) by acting on T cells and acts in diarrheal conditions by improving the fecal biostructure in patients with diarrhea. These diverse mechanisms exerted by S. boulardii provide molecular clues for its effectiveness in diarrheal diseases and intestinal inflammatory conditions with an inflammatory component.

Drug targeting strategies for the treatment of inflammatory bowel disease: a mechanistic update

The therapeutic management of inflammatory bowel disease (IBD) represents the perfect scenario for drug targeting to the site(s) of action. While existing formulation-based targeting strategies include rectal dosage forms and oral systems that target the colon by pH-, time-, microflora- and pressure-triggered drug release, novel approaches for site-specific delivery in IBD therapy will target the inflamed intestine per se rather than intestinal region. The purpose of this article is to present a mechanistic update on the strategies employed to achieve minimal systemic exposure accompanied by maximal drug levels in the inflamed intestinal tissue. The introduction of biological agents, micro/nanoparticulate carriers including liposomes, transgenic bacteria, and gene therapy opportunities are discussed, as well as the challenges remaining to be achieved in the targeted treatment of IBD.