Preventive effects of Bifidobacterium- and Lactobacillus-fermented milk on the development of inflammatory bowel disease in senescence-accelerated mouse P1/Yit strain mice

Long-Term Changes to the Microbiome, Blood Lipid Profiles and IL-6 in Female and Male Swedish Patients in Response to Bariatric Roux-en-Y Gastric Bypass

Lipid metabolism dysregulation is a critical factor contributing to obesity. To counteract obesity-associated disorders, bariatric surgery is implemented as a very effective method. However, surgery such as Roux-en-Y gastric bypass (RYGB) is irreversible, resulting in life-long changes to the digestive tract. The aim of the present study was to elucidate changes in the fecal microbiota before and after RYGB in relation to blood lipid profiles and proinflammatory IL-6. Here, we studied the long-term effects, up to six years after the RYGB procedure, on 15 patients' gut microbiomes and their post-surgery well-being, emphasizing the biological sex of the patients. The results showed improved health among the patients after surgery, which coincided with weight loss and improved lipid metabolism. Health changes were associated with decreased inflammation and significant alterations in the gut microbiome after surgery that differed between females and males. The Actinobacteriota phylum decreased in females and increased in males. Overall increases in the genera Prevotella, Paraprevotella, Gemella, Streptococcus, and Veillonella_A, and decreases in Bacteroides_H, Anaerostipes, Lachnoclostridium_B, Hydrogeniiclostridium, Lawsonibacter, Paludicola, and Rothia were observed. In conclusion, our findings indicate that there were long-term changes in the gut microbiota after RYGB, and shifts in the microbial taxa appeared to differ depending on sex, which should be investigated further in a larger cohort.

Peptides, Exopolysaccharides, and Short-Chain Fatty Acids from Fermented Milk and Perspectives on Inflammatory Bowel Diseases

Crohn's disease and ulcerative colitis are characterized by chronic inflammatory processes and an imbalanced immune response along the gastrointestinal (GI) tract. Pharmacological treatments have been widely used, although their long-term application has adverse side effects. On the other hand, milks fermented with specific lactic acid bacteria (LAB) have been shown to be useful as alternative or complementary aids. Many metabolites such as peptides, exopolysaccharides, and short-chain fatty acids are produced during milk fermentation. These components have been shown to change the pH of the gastrointestinal lumen, aid intestine mucosal recovery, modulate the microbiota, and reduce the inflammatory response (innate and adaptive immune system), both in vitro and in vivo. Therefore, the objective of the present review is to describe how these bioactive compounds from fermented milk by specific LAB can decrease the deleterious symptoms of inflammatory bowel disease.

Microbial-Derived Tryptophan Catabolites, Kidney Disease and Gut Inflammation

Uremic metabolites, molecules either produced by the host or from the microbiota population existing in the gastrointestinal tract that gets excreted by the kidneys into urine, have significant effects on both health and disease. Tryptophan-derived catabolites are an important group of bacteria-produced metabolites with an extensive contribution to intestinal health and, eventually, chronic kidney disease (CKD) progression. The end-metabolite, indoxyl sulfate, is a key contributor to the exacerbation of CKD via the induction of an inflammatory state and oxidative stress affecting various organ systems. Contrastingly, other tryptophan catabolites positively contribute to maintaining intestinal homeostasis and preventing intestinal inflammation—activities signaled through nuclear receptors in particular—the aryl hydrocarbon receptor (AhR) and the pregnane X receptor (PXR). This review discusses the origins of these catabolites, their effect on organ systems, and how these can be manipulated therapeutically in the future as a strategy to treat CKD progression and gut inflammation management. Furthermore, the use of biotics (prebiotics, probiotics, synbiotics) as a means to increase the presence of beneficial short-chain fatty acids (SCFAs) to achieve intestinal homeostasis is discussed.

Malnutrition and Gut Microbiota in Children

Malnutrition continues to threaten the lives of millions across the world, with children being hardest hit. Although inadequate access to food and infectious disease are the primary causes of childhood malnutrition, the gut microbiota may also contribute. This review considers the evidence on the role of diet in modifying the gut microbiota, and how the microbiota impacts childhood malnutrition. It is widely understood that the gut microbiota of children is influenced by diet, which, in turn, can impact child nutritional status. Additionally, diarrhoea, a major contributor to malnutrition, is induced by pathogenic elements of the gut microbiota. Diarrhoea leads to malabsorption of essential nutrients and reduced energy availability resulting in weight loss, which can lead to malnutrition. Alterations in gut microbiota of severe acute malnourished (SAM) children include increased Proteobacteria and decreased Bacteroides levels. Additionally, the gut microbiota of SAM children exhibits lower relative diversity compared with healthy children. Thus, the data indicate a link between gut microbiota and malnutrition in children, suggesting that treatment of childhood malnutrition should include measures that support a healthy gut microbiota. This could be of particular relevance in sub-Saharan Africa and Asia where prevalence of malnutrition remains a major threat to the lives of millions.

Protective effects of potential probiotic Lactobacillus rhamnosus (MTCC-5897) fermented whey on reinforcement of intestinal epithelial barrier function in a colitis-induced murine model

Fermented foods provide essential nutritional components and bioactive molecules that have beneficial effects on several gastrointestinal disorders. In the present investigation, the potential protective effects of whey fermented with probiotic Lactobacillus rhamnosus MTCC-5897 on gastrointestinal health in a murine ulcerative colitis model induced by dextran sulfate sodium (DSS) were evaluated. Pre-consumption of whey fermented with probiotic L. rhamnosus (PFW) before colitis induction significantly reduced (p < 0.01) the disease activity index and improved (p < 0.05) the hematological parameters and histological scores. The considerably diminished levels (p < 0.01) of pro-inflammatory markers (IL-4, TNF-α, CRP and MPO activity) and the enhanced (p < 0.05) levels of the anti-inflammatory cytokine TGF-β with IgA in the intestine upon feeding PFW appeared to prevent inflammation on colitis induction. Transcriptional modulations in pathogen recognition receptors (TLR-2/4) and tight junctional genes (ZO-1, occludin, claudin-1) along with localized distribution of junctional (claudin-1, occludin and ZO-1) and cytoskeleton (actin) proteins improved immune homeostasis and intestinal barrier integrity. Besides, significantly reduced (p < 0.05) levels of the FITC-dextran marker in serum upon consumption of PFW directly confirmed the healthy status of the host gut.

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

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

Alteration of Gut Microbiota in Inflammatory Bowel Disease (IBD): Cause or Consequence? IBD Treatment Targeting the Gut Microbiome

Inflammatory bowel disease (IBD) is a chronic complex inflammatory gut pathological condition, examples of which include Crohn’s disease (CD) and ulcerative colitis (UC), which is associated with significant morbidity. Although the etiology of IBD is unknown, gut microbiota alteration (dysbiosis) is considered a novel factor involved in the pathogenesis of IBD. The gut microbiota acts as a metabolic organ and contributes to human health by performing various physiological functions; deviation in the gut flora composition is involved in various disease pathologies, including IBD. This review aims to summarize the current knowledge of gut microbiota alteration in IBD and how this contributes to intestinal inflammation, as well as explore the potential role of gut microbiota-based treatment approaches for the prevention and treatment of IBD. The current literature has clearly demonstrated a perturbation of the gut microbiota in IBD patients and mice colitis models, but a clear causal link of cause and effect has not yet been presented. In addition, gut microbiota-based therapeutic approaches have also shown good evidence of their effects in the amelioration of colitis in animal models (mice) and IBD patients, which indicates that gut flora might be a new promising therapeutic target for the treatment of IBD. However, insufficient data and confusing results from previous studies have led to a failure to define a core microbiome associated with IBD and the hidden mechanism of pathogenesis, which suggests that well-designed randomized control trials and mouse models are required for further research. In addition, a better understanding of this ecosystem will also determine the role of prebiotics and probiotics as therapeutic agents in the management of IBD.

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

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

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

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

Long-term administration of pDC-Stimulative Lactococcus lactis strain decelerates senescence and prolongs the lifespan of mice

The decline in immune function caused by aging increases the risk of infectious diseases, tumorigeneses and chronic inflammation, resulting in accelerating senescence. We previously reported a lactic acid bacteria, Lactococcus lactis strain Plasma (synonym of Lactococcus lactis subsp. lactis JCM 5805, Lc-Plasma), that stimulates plasmacytoid dendritic cells (pDCs), which play a crucial role in phylaxis from viral infection. In this study, we investigated the anti-aging effects of long-term oral administration of Lc-Plasma in a senescence-accelerated mouse strain, SAMP6. Mice given Lc-Plasma showed a significant improvement in survival rate at 82 weeks and a decreased senescence score as compared with control mice throughout this study. Anatomic analysis at 82 weeks revealed that the frequency of altered hepatocellular foci was significantly lower, and the incidence of other pathological findings in the liver and lungs tended to be lower in Lc-Plasma mice than in control mice. Transcription level of the IL-1β gene in lungs also tended to be lower in Lc-Plasma mice. Furthermore, the thinning of skin and age-related decrease in muscle mass were also significantly suppressed in the Lc-Plasma group as compared with the control group. Consistent with these phenotypic features, pDCs activity was significantly higher in Lc-Plasma mice than in control mice. In conclusion, long-term administration of Lc-Plasma can decelerate senescence and prolong lifespan via maintenance of the immune system due to activation of pDCs.

Lower Level of Bacteroides in the Gut Microbiota Is Associated with Inflammatory Bowel Disease: A Meta-Analysis

Background and Aims. Multiple studies have reported associations between inflammatory bowel disease (IBD) and the flora disequilibrium of Bacteroides. We performed a meta-analysis of the available data to provide a more precise estimate of the association between Bacteroides level in the gut and IBD. Methods. We searched PubMed/MEDLINE, EMBASE, Cochrane Library, Wiley Library, BIOSIS previews, Web of Science, CNKI, and ScienceDirect databases for published literature on IBD and gut microbiota from 1990 to 2016. Quality of all eligible studies was assessed using the Newcastle-Ottawa Quality Assessment Scale (NOS). We compared the level of Bacteroides in IBD patients with that in a control group without IBD, different types of IBD patients, and IBD patients with active phase and in remission. Results. We identified 63 articles, 9 of which contained sufficient data for evaluation. The mean level of Bacteroides was significantly lower in Crohn's disease (CD) and ulcerative colitis (UC) patients in active phase than in normal controls. The level of Bacteroides in remission CD and UC patients was much lower than patients in the control group. Bacteroides level was even lower in patients with CD and UC in active phase than in remission. Conclusions. This analysis suggests that lower levels of Bacteroides are associated with IBD, especially in active phase.

Disturbance in the Mucosa-Associated Commensal Bacteria Is Associated with the Exacerbation of Chronic Colitis by Repeated Psychological Stress; Is That the New Target of Probiotics?

Psychological stress can exacerbate inflammatory bowel disease. However, the mechanisms underlying how psychological stress affects gut inflammation remain unclear. Here, we focused on the relationship between changes in the microbial community of mucosa-associated commensal bacteria (MACB) and mucosal immune responses induced by chronic psychological stress in a murine model of ulcerative colitis. Furthermore, we examined the effect of probiotic treatment on exacerbated colitis and MACB composition changes induced by chronic psychological stress. Repeated water avoidance stress (rWAS) in B6-Tcra-/- mice severely exacerbated colitis, which was evaluated by both colorectal tissue weight and histological score of colitis. rWAS treatment increased mRNA expression of UCN2 and IFN-γ in large intestinal lamina propria mononuclear cells (LI-LPMC). Interestingly, exacerbated colitis was associated with changes in the microbial community of MACB, specifically loss of bacterial species diversity and an increase in the component ratio of Clostridium, revealed by 16S rRNA gene amplicon analysis. Finally, the oral administration of a probiotic Lactobacillus strain was protective against the exacerbation of colitis and was associated with a change in the bacterial community of MACB in rWAS-exposed Tcra-/- mice. Taken together, these results suggested that loss of species diversity in MACB might play a key role in exacerbated colitis induced by chronic psychological stress. In addition, probiotic treatment may be used as a tool to preserve the diversity of bacterial species in MACB and alleviate gut inflammation induced by psychological stress.

Intestinal Flora Modification of Arthritis Pattern in Spondyloarthropathy

BACKGROUND

The reactive form of spondyloarthropathy appears inducible by exposure to agents of infectious diarrhea, but do those organisms represent the tip of the iceberg, as indicated by renewed interest in gastrointestinal flora? Prevalence of spondyloarthropathy (20% of chimpanzees [Pan] and 28% of gorillas) is independent of subspecies and species, respectively. However, there are major differences in arthritis patterns, a characteristic shared with humans.

OBJECTIVES

Do patterns of arthritis correlate with gastrointestinal flora? Could such associated modifications be in the form of disease induction or represent protective effectors (at least against the extent of peripheral arthritis)?

METHODS

The skeletons of 2 chimpanzee subspecies (79 Pan troglodytes troglodytes and 26 Pan troglodytes schweinfurthii) and 2 gorilla species (99 Gorilla gorilla and 38 Gorilla beringei) adults were examined, and arthritis pattern noted. Feces of Eastern (P. schweinfurthii and G. beringei) and Western (great apes collected in their normal ranges) apes were assessed for 16S rRNA c and its character.

RESULTS

Patterns of arthritis recognized on examination of skeletons showed geographic variation in skeletal distribution. East African apes (P. troglodytes schweinfurthii and G. beringei) had pauciarticular arthritis and frequent sacroiliac disease, whereas West African apes (P. troglodytes troglodytes and G. gorilla) had polyarticular peripheral joint disease with minimal sacroiliac involvement. DNA evidence revealed that Corynebactericeae were prominently represented in great apes with polyarticular disease, whereas Dietzia and Bifidobacterium exposure correlated with reduced peripheral joint arthritis distribution.

CONCLUSIONS

Suggestions of a protective effect (in this case, limiting extent of peripheral arthritis, but not the disease itself) offered by these organisms are well represented by documented effects in other diseases (eg, tuberculosis) in the zoologic record. Perhaps it is this disease-modifying character that reduces the extent of the peripheral erosive disease, while increasing propensity to axial (sacroiliac) disease. A potential role for probiotic organisms in management of arthritis in humans is suggested, as has been documented for tuberculosis, gastrointestinal disorders, and food allergies.

Differences in the Biodiversity of the Fecal Microbiota of Infants With Rotaviral Diarrhea and Healthy Infants

BACKGROUND

Rotaviral diarrhea (RD) has been associated with the biodiversity of the fecal microbiota in infants; however, the differences in the biodiversity of the fecal microbiota between infants with RD and healthy (H) infants have not been clearly elucidated.

OBJECTIVES

This study aimed to reveal the changes in the biodiversity of the fecal microbiota of infants with RD.

PATIENTS AND METHODS

For this study, 30 fecal samples from 15 RD infants and 15 H infants were collected. The biodiversity of the fecal microbiota from the two groups was compared via polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) and gene sequencing.

RESULTS

The Shannon-Weaver index showed that the biodiversity of the fecal microbiota from the RD infants was significantly lower (P < 0.05) than that from the H infants. All fifteen RD infants were grouped into one cluster and were separated from the H infants by the un weighted-pair group method, with the arithmetic average (UPGMA) clustering algorithm. In addition, when compared with the healthy infants, the communities of the dominant microbes, Lactobacillus and Bifidobacterium, in the fecal microbiota from the RD infants have obviously changed.

CONCLUSIONS

With regard to improving the understanding of the differences in the biodiversity of the fecal microbiota between RD infants and H infants, the findings of this study can provide a possible basis to reveal the relationship between RD and intestinal microbiota.

Chronic Psychological Stress Disrupted the Composition of the Murine Colonic Microbiota and Accelerated a Murine Model of Inflammatory Bowel Disease

The effect of psychological stress on the gastrointestinal microbiota is widely recognized. Chronic psychological stress may be associated with increased disease activity in inflammatory bowel disease, but the relationships among psychological stress, the gastrointestinal microbiota, and the severity of colitis is not yet fully understood. Here, we examined the impact of 12-week repeated water-avoidance stress on the microbiota of two inbred strains of T cell receptor alpha chain gene knockout mouse (background, BALB/c and C57BL/6) by means of next-generation sequencing of bacterial 16S rRNA genes. In both mouse strains, knockout of the T cell receptor alpha chain gene caused a loss of gastrointestinal microbial diversity and stability. Chronic exposure to repeated water-avoidance stress markedly altered the composition of the colonic microbiota of C57BL/6 mice, but not of BALB/c mice. In C57BL/6 mice, the relative abundance of genus Clostridium, some members of which produce the toxin phospholipase C, was increased, which was weakly positively associated with colitis severity, suggesting that expansion of specific populations of indigenous pathogens may be involved in the exacerbation of colitis. However, we also found that colitis was not exacerbated in mice with a relatively diverse microbiota even if their colonic microbiota contained an expanded phospholipase C-producing Clostridium population. Exposure to chronic stress also altered the concentration of free immunoglobulin A in colonic contents, which may be related to both the loss of bacterial diversity in the colonic microbiota and the severity of the colitis exacerbation. Together, these results suggest that long-term exposure to psychological stress induces dysbiosis in the immunodeficient mouse in a strain-specific manner and also that alteration of microbial diversity, which may be related to an altered pattern of immunoglobulin secretion in the gastrointestinal tract, might play a crucial role in the development of chronic stress-induced colitis.

A Microbial Feed Additive Abates Intestinal Inflammation in Atlantic Salmon

The efficacy of a microbial feed additive (Bactocell^®) in countering intestinal inflammation in Atlantic salmon was examined in this study. Fish were fed either the additive-coated feed (probiotic) or feed without it (control). After an initial 3-week feeding, an inflammatory condition was induced by anally intubating all the fish with oxazolone. The fish were offered the feeds for 3 more weeks. Distal intestine from the groups was obtained at 4 h, 24 h, and 3 weeks, after oxazolone treatment. Inflammatory responses were prominent in both groups at 24 h, documented by changes in intestinal micromorphology, expression of inflammation-related genes, and intestinal proteome. The control group was characterized by edema, widening of intestinal villi and lamina propria, infiltration of granulocytes and lymphocytes, and higher expression of genes related to inflammatory responses, mul1b, il1b, tnfa, ifng, compared to the probiotic group or other time points of the control group. Further, the protein expression in the probiotic group at 24 h after inducing inflammation revealed five differentially regulated proteins – Calr, Psma5, Trp1, Ctsb, and Naga. At 3 weeks after intubation, the inflammatory responses subsided in the probiotic group. The findings provide evidence that the microbial additive contributes to intestinal homeostasis in Atlantic salmon.

Intestinal microbiota, probiotics and prebiotics in inflammatory bowel disease

It has been presumed that aberrant immune response to intestinal microorganisms in genetically predisposed individuals may play a major role in the pathogenesis of the inflammatory bowel disease, and there is a good deal of evidence supporting this hypothesis. Commensal enteric bacteria probably play a central role in pathogenesis, providing continuous antigenic stimulation that causes chronic intestinal injury. A strong biologic rationale supports the use of probiotics and prebiotics for inflammatory bowel disease therapy. Many probiotic strains exhibit anti-inflammatory properties through their effects on different immune cells, pro-inflammatory cytokine secretion depression, and the induction of anti-inflammatory cytokines. There is very strong evidence supporting the use of multispecies probiotic VSL#3 for the prevention or recurrence of postoperative pouchitis in patients. For treatment of active ulcerative colitis, as well as for maintenance therapy, the clinical evidence of efficacy is strongest for VSL#3 and Escherichia coli Nissle 1917. Moreover, some prebiotics, such as germinated barley foodstuff, Psyllium or oligofructose-enriched inulin, might provide some benefit in patients with active ulcerative colitis or ulcerative colitis in remission. The results of clinical trials in the treatment of active Crohn's disease or the maintenance of its remission with probiotics and prebiotics are disappointing and do not support their use in this disease. The only exception is weak evidence of advantageous use of Saccharomyces boulardii concomitantly with medical therapy in maintenance treatment.

Immunopathological characterization of selected mouse models of inflammatory bowel disease: Comparison to human disease

Inflammatory bowel diseases (IBD) are chronic, relapsing conditions of multifactorial etiology. The two primary diseases of IBD are Crohn's disease (CD) and ulcerative colitis (UC). Both entities are hypothesized to occur in genetically susceptible individuals due to microbial alterations and environmental contributions. The exact etiopathogenesis, however, is not known for either disease. A variety of mouse models of CD and UC have been developed to investigate the pathogenesis of these diseases and evaluate treatment modalities. Broadly speaking, the mouse models can be divided into 4 categories: genetically engineered, immune manipulated, spontaneous and erosive/chemically induced. No one mouse model completely recapitulates the immunopathology of CD or UC, however each model possesses particular similarities to human IBD and offers advantageous for specific details of IBD pathogenesis. Here we discuss the more commonly used models in each category and critically evaluate how the immunopathology induced compares to CD or UC, as well as the advantages and disadvantages associated with each model.

In case of obesity, longevity-related mechanisms lead to anti-inflammation

The exact mechanisms which contribute to longevity have not been figured out yet. Our aim was to find out a common way for prompting longevity by bringing together the well-known applications such as food restriction, exercise, and probiotic supplementing in an experimental obesity model. Experimental obesity was promoted in a total of 32 young (2 months old) and 32 aged (16 months old) male Wistar albino rats through 8-week cafeteria diet (salami, chocolate, chips, and biscuits). Old and young animals were divided into groups each consisting of eight animals and also divided into four subgroups as obese control, obese food restriction, obese probiotic-fed and obese exercise groups. Probiotic group diet contained 0.05 %w/total diet inactive and lyophilized Lactobacillus casei str. Shirota. The exercise group was subjected to treadmill running 1 h/day, at 21 m/min and at an uphill incline of 15 % for 5 days a week. Food restriction group was formed by giving 40 % less food than the others. The control group was fed regular pellet feed ad libitum. This program was continued for 16 weeks. Blood samples from all the groups were analyzed for fasting glucose, insulin, IGF-1, insulin-like growth factor binding protein 3 (IGFBP-3), interleukin (IL)-6, IL-12, malondialdehyde (MDA), fT3, TT3, fT4, TT4, and liver tissue MDA levels were measured. All applications showed anti-inflammatory effects through the observed changes in the levels of IGFBP-3, IL-6, and IL-12 in the young and old obese rats. While the interventions normally contribute to longevity by recruiting different action mechanisms, anti-inflammatory effect is the only mode of action for all the applications in the obesity model.

The biodiversity and composition of the dominant fecal microbiota in patients with inflammatory bowel disease

Clinical and experimental observations in animal models indicate that intestinal commensal bacteria are involved in the initiation and amplification of inflammatory bowel disease (IBD). As the majority of colonic bacteria cannot be identified by culture techniques, the aim of this study was to use sequence-based methods to investigate and characterize the composition of the dominant fecal microbiota in both patients with inflammatory bowel disease and healthy subjects. Fecal microbiota was isolated and quantified using real-time quantitative polymerase chain reaction. Denaturing gradient gel electrophoresis (DGGE) of 16S rDNA was used to evaluate the diversity of the dominant species. Analysis of individual bacterial groups showed a greater change in the fecal microbiota of patients with IBD, especially in those with active ulcerative colitis and active Crohn's disease. DGGE demonstrated the diversity of microbial flora in ulcerative colitis and Crohn's disease was less than in healthy subjects. Our results provide a better understanding of changes in fecal microbiota among patients with inflammatory bowel disease.

SAMP1/YitFc mouse strain: a spontaneous model of Crohn's disease-like ileitis

The SAMP1/YitFc mouse strain represents a model of Crohn's disease (CD)-like ileitis that is ideal for investigating the pathogenesis of chronic intestinal inflammation. Different from the vast majority of animal models of colitis, the ileal-specific phenotype characteristic of SAMP1/YitFc mice occurs spontaneously, without genetic, chemical, or immunological manipulation. In addition, SAMP1/YitFc mice possess remarkable similarities to the human condition with regard to disease location, histologic features, incidence of extraintestinal manifestations, and response to conventional therapies. SAMP1/YitFc mice also display a well-defined time course of a predisease state and phases of acute and chronic ileitis. As such, the SAMP1/YitFc model is particularly suitable for elucidating pathways that precede the clinical phenotype that may lead to preventive, and therefore more efficacious, intervention with the natural course of disease, or alternatively, for the development of therapeutic strategies directed against chronic, established ileitis. In this review we summarize important contributions made by our group and others that uncover potential mechanisms in the pathogenesis of CD using this unique murine model of chronic intestinal inflammation.

Probiotic lactic acid bacteria in the gastro-intestinal tract: health benefits, safety and mode of action

Lactic acid bacteria (LAB) have received considerable attention as probiotics over the past few years. This concept has grown from traditional dairy products to a profitable market of probiotic health supplements and functional foods. Extensive research is done on novel potential probiotic strains, with specific emphasis on their health benefits and mode of action. Criteria for the selection of probiotic strains have only recently been formulated by the Food and Agriculture Organization of the United Nations and the World Health Organization (FAO/WHO). Several in vitro techniques have been developed to evaluate the probiotic properties of strains. In many cases, this is followed by in vivo tests. Safety studies are also obligatory, as a few cases of bacteremia caused by LAB have been reported. This review focuses on the health benefits and safety of LAB probiotics, the criteria used to select a probiotic, mode of action and the impact these organisms have on natural microbiota in the gastro-intestinal tract.

Identification and quantification of viable Bifidobacterium breve strain Yakult in human faeces by using strain-specific primers and propidium monoazide

AIMS

To develop a quick and accurate PCR-based method to evaluate viable Bifidobacterium breve strain Yakult (BbrY) in human faeces.

METHODS AND RESULTS

The number of BbrY in faeces was detected by using strain-specific quantitative real-time PCR (qPCR) derived from a randomly amplified polymorphic DNA analysis. And using propidium monoazide (PMA) treatment, which combined a DNA-intercalating dye for covalently linking DNA in dead cells and photoactivation, only viable BbrY in the faeces highly and significantly correlated with the number of viable BbrY added to faecal samples within the range of 10(5) -10(9) cells per g of faeces was enumerated. After 11 healthy subjects ingested 10·7 log CFU of BbrY daily for 10 days, 6·9 (± 1·5) log CFU g(-1) [mean (± SD)] of BbrY was detected in faeces by using strain-specific transgalactosylated oligosaccharide-carbenicillin (T-CBPC) selective agar medium. Viable BbrY detected by qPCR with PMA treatment was 7·5 (± 1·0) log cells per g and the total number (viable and dead) of BbrY detected by qPCR without PMA treatment was 8·1 (± 0·8) log cells per g.

CONCLUSIONS

Strain-specific qPCR with PMA treatment evaluated viable BbrY in faeces quickly and accurately.

SIGNIFICANCE AND IMPACT OF THE STUDY

Combination of strain-specific qPCR and PMA treatment is useful for evaluating viable probiotics and its availability in humans.

Microcalorimetric assay on the antimicrobial property of five hydroxyanthraquinone derivatives in rhubarb (Rheum palmatum L.) to Bifidobacterium adolescentis

It was found that the intestinal bacteria balance would be deteriorated by rhubarb especially in long term treatment. Bifidobacteria is one of the most common species of probiotics in human intestine. The suppression of this particular probiotic, such as Bifidobacterium adolescentis, one of the dominant anaerobes in the intestines of humans, might lead to imbalance of intestinal flora and is considered to be potentially riskful for human health. Hence, the inhibitory effects of the five main components of hydroxyanthraquinones (HAQs) contained in rhubarb on B. adolescentis growth were investigated by microcalorimetry to discover the suppression potential of rhubarb and the structure-function relationship of such HAQs. The value of the maximum power- output (P(max)) and slope (k) of the thermogenic growth curves of B. adolescentis were found of decrease in the presence of the five HAQs, while the peak time (T(p)) of the thermogenic curves were found to be delayed. The sequence of antimicrobial activity of the five HAQs is rhein>emodin>aloe-emodin>chrysophanol>physicion. The functional groups carboxyl, hydroxyl and hydroxylmethyl on phenyl ring in HAQs could improve the antimicrobial activity. The influence of substituent groups on anti- B. adolescentis activity might be related with the polarity and the sequence was carboxyl>hydroxyl>hydroxylmethyl>methyl and methoxyl.

Influence of long-term consumption of a Lactococcus lactis strain on the intestinal immunity and intestinal flora of the senescence-accelerated mouse

The senescence-accelerated mouse develops normally until 5-6 months of age and then displays rapid and irreversible advancement of senescence manifesting as clinical signs and gross lesions. To clarify the effect of lactic acid bacteria on the physiological changes with increasing age, heat-killed Lactococcus lactis G50 was administered to 1-month-old senescence-accelerated-prone mouse (SAMP)6 mice for 11 months, a senescence-accelerated mouse strain that develops senile osteoporosis. Mice fed G50 gained more weight than the control mice (not fed G50) during the feeding experiment. Faecal IgA levels in the mice fed G50 at 3 months were higher than those of the control mice but decreased to control levels with increasing age. The numbers of viable cells of Bacteroides sp., Lactobacillus sp., Staphylococcus sp., Enterococcus/Streptococcus sp. and Enterobacteriaceae sp. in faeces were similar for mice fed the G50 and control diets at any age, but strain G50 suppressed the intestinal growth of H2S-producing bacteria. Bone density of the thigh bone did not differ between aged G50 and control mice. Strain G50 would be a beneficial bacterium for the enhancement of intestinal immunity during youth and to suppress the growth of harmful intestinal bacteria. The applicability of strain G50 for the food and animal industries has been proposed in the present study.

A component of polysaccharide peptidoglycan complex on Lactobacillus induced an improvement of murine model of inflammatory bowel disease and colitis-associated cancer

Interleukin-6 (IL-6)/signal transducer and activator of transcription 3 (STAT3) signals play key roles in the pathogenesis of inflammatory bowel disease (IBD). We previously described that both intact cells and a cell wall-derived polysaccharide-peptidoglycan complex (PSPG) in a strain of lactobacillus [Lactobacillus casei Shirota (LcS)] inhibited IL-6 production in lipopolysaccharide (LPS)-stimulated lamina propria mononuclear cells (LPMCs) isolated from murine IBD. Diets with LcS improve murine IBD by suppression of IL-6 synthesis in LPMCs. Moreover, LcS supplementation with fermented milk ameliorates disease activity in patients with active ulcerative colitis. Here, we focused on the specific roles of PSPG in LcS concerning their anti-inflammatory actions. PSPG derived from LcS, and no other strain of lactobacilli, inhibited IL-6 production in LPS-stimulated murine IBD LPMCs. Purified PSPG-I from LcS inhibited IL-6 synthesis in LPS-stimulated murine IBD LPMCs through the inhibition of nuclear factor-kappaB. The anti-IL-6 action of LcS PSPG was abrogated by masking with monoclonal anti-PSPG-I. Furthermore, PSPG-I-negative L. casei strains (PSPG-I-negative mutant LcS: LC(DeltaPSPG-I), L. casei ATCC 334) did not inhibit IL-6 production. Finally, we confirmed the effects of PSPG-I on LcS in the models of both IBD and colitis-associated cancer (CAC). In the IBD model, ingestion of LcS improved ileitis and inhibited activation of IL-6/STAT3 signaling, while ingestion of the LC(DeltaPSPG-I) strain did not. In the CAC model, treatment with LcS, but not the LC(DeltaPSPG-I) strain, showed tumour-suppressive effects with an inhibition of IL-6 production in the colonic mucosa. These results suggested that a specific polysaccharide component in an L. casei strain plays a crucial role in its anti-inflammatory actions in chronic intestinal inflammatory disorders.

Antimicrobial susceptibility of Bifidobacterium breve strains and genetic analysis of streptomycin resistance of probiotic B. breve strain Yakult

The minimum inhibitory concentrations (MICs) of 17 antimicrobials for 26 Bifidobacterium breve strains of various origins were determined by broth microdilution. MIC distributions for 17 antimicrobials except streptomycin and tetracycline were unimodal for all strains tested, whereas bimodal distributions were observed for streptomycin and tetracycline. The probiotic strain B. breve strain Yakult showed intrinsic susceptibility to all antimicrobials except streptomycin to which the strain showed an atypically higher MIC of >256 microg/ml. Because this strain is a commercial strain, which is often ingested by many consumers on a daily basis, it is very important to determine the genetic basis for streptomycin resistance of this strain. Molecular analysis revealed that a mutation of the rpsL gene for ribosomal protein S12 was responsible for this streptomycin resistance. The resistance of B. breve strain Yakult to streptomycin, therefore, is caused by a chromosomal mutation and very unlikely to be transferred to other microorganisms.

Inflammatory bowel disease: a model of chronic inflammation-induced cancer

Chronic inflammation is a well-recognized risk factor for the development of human cancer. Inflammatory bowel disease (IBD), including ulcerative colitis and Crohn's disease, is a typical longstanding inflammatory disease of the colon with increased risk for the development of colorectal carcinoma. Several molecular events involved in chronic inflammatory process may contribute to multistage progression of human cancer development, including the overproduction of reactive oxygen and nitrogen species, overproduction/activation of key arachidonic acid metabolites and cytokines/growth factors, and immunity system dysfunction. Multiple animal models of IBD have been established, and in general, these models can be mainly categorized into chemically induced, genetically engineered (transgenic or gene knock-out), spontaneous, and adoptive transferring animal models. This chapter mainly focuses on (1) epidemiologic and molecular evidence on IBD and risk of colorectal cancer, (2) molecular pathogenesis of IBD-induced carcinogenesis, and (3) modeling of IBD-induced carcinogenesis in rodents and its application.

Rationale for Using of Bifidobacterium Probiotic Strains-Fermented Milk Against Colitis Based on Animal Experiments and Clinical Trials

Probiotic foods such as probiotic strain-fermented milk or supplements proposing various health claims are now available. The beneficial effects of these probiotic foods on the digestive system are expected for not only healthy persons but also patients with diseases of the alimentary tract. This review focused on the rationale of using our Bifidobacterium strains-fermented milk as an adjunct for the prevention of recurrence or exacerbation of colitis. Animal experiments using gnotobiotic colitis or spontaneously colitis models and also human clinical trials of ulcerative colitis patients showed the potential of Bifidobacterium strains-fermented milk as a beneficial anti-colitis adjunct.

The effect of long-term lactobacilli (lactic acid bacteria) enteral treatment on the central nervous system of growing rats

The aim of this study was to explore the relationship between consumption of large doses of lactic acid bacteria (LAB) and the behaviour and brain morphobiochemistry of normal growing rats. Four groups of rats were treated with LAB cultures twice daily for 6 months. The control group received 1 ml of saline per treatment, while two experimental groups received 1 ml of living bacteria (Lactobacillus plantarum and Lactobacillus fermentum, respectively) and the remaining group received a heat-treated (inactivated) L. fermentum culture. After 2 and 6 months of treatment, respectively, eight animals from each group were sacrificed, and specimens were taken for further analyses. The behaviour of the rats was evaluated five times in an open-field test at monthly intervals throughout the study. Lactobacilli treatment for 2 months induced changes in the motoric behaviour of the rats. The concentration of the astrocytesoluble and filament glial fibrillary acidic protein (GFAP) decreased in the posterior part of the hemispheres, including the thalamus, hippocampus and cortex of the rats treated with L. fermentum. A greater decrease in filament GFAP (up to 50%) was shown in the group receiving the live form of L. fermentum. In contrast, the GFAP in the live L. plantarum-treated group increased, showing elevated levels of the soluble and filament forms of GFAP in the posterior part of the hemispheres. A 60-66% decrease in the amount of the astrocyte-specific Ca-binding protein S-100b was shown in the posterior parts of the hemispheres and in the hindbrain of rats given LAB for 2 months. Prolonged feeding with LAB for 4 months up to full adulthood led to a further decrease in astrocyte reaction, reflected as an additional decrease in the amount of soluble GFAP and locomotor activity in all experimental groups. The changes in filament GFAP and S-100b appeared to disappear after prolonged feeding (total of 6 months) with LAB. In summary, LAB dietary treatment affected the ontogenetic development of the astrocytes, with the highest intensity observed in the early stages of rat development. It can be postulated that LAB treatment may play a preventive role in neurological diseases by decreasing astrocyte reaction and, consequently, lowering locomotor activity.

Anti-inflammatory activity of probiotic Bifidobacterium: Enhancement of IL-10 production in peripheral blood mononuclear cells from ulcerative colitis patients and inhibition of IL-8 secretion in HT-29 cells

AIM: To determine the anti-inflammatory activity of probiotic Bifidobacteria in Bifidobacteria-fermented milk (BFM) which is effective against active ulcerative colitis (UC) and exacerbations of UC, and to explore the immunoregulatory mechanisms.

METHODS: Peripheral blood mononuclear cells (PBMNC) from UC patients or HT-29 cells were co-cultured with heat-killed probiotic bacteria or culture supernatant of Bifidobacterium breve strain Yakult (BbrY) or Bifidobacterium bifidum strain Yakult (BbiY) to estimate the amount of IL-10 or IL-8 secreted.

RESULTS: Both strains of probiotic Bifidobacteria contained in the BFM induced IL-10 production in PBMNC from UC patients, though BbrY was more effective than BbiY. Conditioned medium (CM) and DNA of both strains inhibited IL-8 secretion in HT-29 cells stimulated with TNF-α, whereas no such effect was observed with heat-killed bacteria. The inhibitory effect of CM derived from BbiY was greater than that of CM derived from BbrY. DNAs of the two strains had a comparable inhibitory activity against the secretion of IL-8. CM of BbiY induced a repression of IL-8 gene expression with a higher expression of IκB-ζ mRNA 4 h after culture of HT-29 cells compared to that in the absence of CM.

CONCLUSION: Probiotic Bifidobacterium strains in BFM enhance IL-10 production in PBMNC and inhibit IL-8 secretion in intestinal epithelial cells, suggesting that BFM has anti-inflammatory effects against ulcerative colitis.

Probiotics and prebiotics in inflammatory bowel disease: microflora 'on the scope'

The intestinal microflora is a large bacterial community that colonizes the gut, with a metabolic activity equal to an organ and various functions that affect the physiology and pathology of the host's mucosal immune system. Intestinal bacteria are useful in promotion of human health, but certain components of microflora, in genetically susceptible individuals, contribute to various pathological disorders, including inflammatory bowel disease. Clinical and experimental observations indicate an imbalance in protective and harmful microflora components in these disorders. Manipulation of gut flora to enhance its protective and beneficial role represents a promising field of new therapeutic strategies of inflammatory bowel disease. In this review, we discuss the implication of gut flora in the intestinal inflammation that justifies the role of probiotics and prebiotics in the prevention and treatment of inflammatory bowel disease and we address the evidence for therapeutic benefits from their use in experimental models of colitis and clinical trials.

Alterations in intestinal microbial flora and human disease

PURPOSE OF REVIEW

To highlight the evidence supporting the role of altered commensal gut flora in human disease. While the contribution of the indigenous gut microbial community is widely recognized, only recently has there been evidence pointing to indigenous flora in disease.

RECENT FINDINGS

This review discusses recent evidence pointing to the role of altered commensal gut flora in such common conditions as irritable bowel syndrome and inflammatory bowel disease. Recent studies document the intricate relationship between the vast population of microbes that live in our gut and the human host. Since increased intestinal permeability and immune activation are consequences of an altered host-gut microbial relationship, what are the clinical effects of this shift in relationship?

SUMMARY

We focus on the example of an abnormal expansion of gut microbial flora into the small bowel or small intestinal bacterial overgrowth and discuss the effects of bacterial overgrowth on the human host in acute pancreatitis, bacterial gastroenteritis, irritable bowel syndrome, inflammatory bowel disease, hepatic encephalopathy, and fibromyalgia and burn injury. The identification of the underlying role of altered commensal gut microbiota in these and other human diseases could lead to novel diagnostic and therapeutic strategies that would improve clinical outcome.

Anti-ageing effect of a lactococcal strain: analysis using senescence-accelerated mice

The effects of oral administration of a lactococcal strain on physiological changes associated with ageing were investigated using senescence-accelerated mice (SAM). SAM develop normally, but then show an early onset and irreversible advancement of senescence. SAMP6 is a SAM strain that develops osteoporosis with ageing. Oral administration of heat-killedLactococcus lactissubsp.cremorisH61 (strain H61) to aged SAMP6 mice was associated with reduced bone density loss, a suppression of incidence of skin ulcers and reduced hair loss, compared with controls. Spleen cells from mice fed strain H61 produced more interferon-γ and IL-12 than those from control mice, suggesting that administration of strain H61 altered immune responses. The numbers of viable cells ofBifidobacteriumsp.,Bacteroidessp. andEnterococcussp. in faeces were similar for mice fed the strain H61 and control diets, but counts forStaphylococcussp. were significantly lower (P < 0·05) in mice fed strain H61. Mice fed strain H61 had similar serum concentrations of thiobarbituric acid-reactive substances as in controls, indicating a lack of effect on lipid peroxidation status. Administration of living cells of strain H61 or fermented milk containing strain H61 was also associated with a suppression of incidence of skin ulcers and reduced hair loss. These results indicate that oral administration of strain H61 has the potential to suppress some of the manifestations associated with ageing.

Imbalance in intestinal microflora constitution could be involved in the pathogenesis of inflammatory bowel disease

Since genetically engineered animal models of inflammatory bowel disease (IBD) do not develop colitis under germ-free conditions, the intestinal microflora is thought to be one of the most important environmental factors associated with IBD. To understand the involvement of intestinal microflora in the pathogenesis of IBD, we analyzed the constituents of intestinal microflora in IBD. Faecal samples from 73 patients with ulcerative colitis (UC) and 23 patients with Crohn's disease (CD) were analyzed by quantitative PCR using 16S rRNA gene-targeted group-specific primers for Bacteroides fragilis group, Bifidobacterium, Clostridium coccoides groups, Clostridium leptum subgroup, Atopobium cluster, and seven species of Bacteroides. We analyzed the distribution of the predominant microflora by fluorescence in situ hybridization (FISH) using group-specific probes. We also examined the concentration of faecal organic acids produced by intestinal microflora. Contrary to previous reports, we found that the B. fragilis group was significantly decreased in the faeces of patients with IBD. Moreover, B. vulgatus was the predominant microflora in healthy controls and relatively decreased among IBD patients. Most of the microflora adhering to the colonic mucosa surrounding the mucus layer comprised C. coccoides group and Bifidobacterium. B. fragilis group mainly inhabited the faeces, but did not adhere to or invade the mucosa. The concentrations of propionic and butyric acids in the faeces were significantly decreased in patients with IBD. These findings indicate that IBD is not caused by a specific intestinal bacterial cluster or species and that disordered intestinal microflora could be involved in the pathogenesis of IBD.

Administration of Lactobacillus evokes coordinated changes in the intestinal expression profile of genes regulating energy homeostasis and immune phenotype in mice

Lactic acid bacteria are probiotics widely used in functional food products, with a variety of beneficial effects reported. Recently, intense research has been carried out to provide insight into the mechanism of the action of probiotic bacteria. We have used gene array technology to map the pattern of changes in the global gene expression profile of the host caused by Lactobacillus administration. Affymetrix microarrays were applied to comparatively characterize differences in gene transcription in the distal ileum of normal microflora (NMF) and germ-free (GF) mice evoked by oral administration of two Lactobacillus strains used in fermented dairy products today - Lactobacillus paracasei ssp. paracasei F19 (L. F19) or Lactobacillus acidophilus NCFB 1748. We show that feeding either of the two strains caused very similar effects on the transcriptional profile of the host. Both L. F19 and L. acidophilus NCFB 1748 evoked a complex response in the gut, reflected by differential regulation of a number of genes involved in essential physiological functions such as immune response, regulation of energy homeostasis and host defence. Notably, the changes in intestinal gene expression caused by Lactobacillus were different in the mice raised under GF v. NMF conditions, underlying the complex and dynamic nature of the host-commensal relationship. Differential expression of an array of genes described in this report evokes novel hypothesis of possible interactions between the probiotic bacteria and the host organism and warrants further studies to evaluate the functional significance of these transcriptional changes on the metabolic profile of the host.

Effect of Bifidobacterium infantis on Interferon- gamma- induced keratinocyte apoptosis: a potential therapeutic approach to skin immune abnormalities

Current management of atopic dermatitis is mainly directed to the reduction of cutaneous inflammation. Since patients with atopic dermatitis show abnormalities in immunoregulation, a therapy aimed to adjust their immune function could represent an alternative approach, particularly in the severe form of the disease. Indeed, T-lymphocytes constitute a large population of cellular infiltrate in atopic/allergic inflammation and a dysregulated T-cell induced keratinocyte apoptosis appears to be an important pathogenetic factor of the eczematous disease. In recent years, attention has been focused on the interaction between host and probiotics which may have anti-inflammatory properties and immunomodulatory activities. The aim of the present work is to investigate the effect of a selected probiotic extract, the Bifidobacterium infantis extract, on a human keratinocyte cell line (HaCaT) abnormal apoptosis induced by activated-T-lymphocyte. An in vitro model of atopic dermatitis was used to assess the ability of the probiotic extract to protect HaCaT from apoptosis induced by soluble factors (IFN-gamma and CD95 ligand) released by human T-lymphocytes in vitro activated with anti-CD3/CD28 mAbs or Phytohemoagglutinin. Evidence is given that the bacterial extract treatment was able to totally prevent T lymphocyte-induced HaCaT cell apoptosis in vitro. The mechanism underlying this inhibitory effect has been suggested to depend on the ability of the bacterial extract to significantly reduce anti-CD3/CD28 mAbs and mitogen-induced T-cell proliferation, IFN-gamma generation and CD95 ligand release. These preliminary results may represent an experimental basis for a potential therapeutic approach mainly targeting the skin disorders-associated immune abnormalities.

Therapeutic approaches targeting intestinal microflora in inflammatory bowel disease

Inflammatory bowel diseases, ulcerative colitis, and Crohn’s disease, are chronic intestinal disorders of unknown etiology in which in genetically susceptible individuals, the mucosal immune system shows an aberrant response towards commensal bacteria. The gastrointestinal tract has developed ingenious mechanisms to coexist with its autologous microflora, but rapidly responds to invading pathogens and then returns to homeostasis with its commensal bacteria after the pathogenic infection is cleared. In case of disruption of this tightly-regulated homeostasis, chronic intestinal inflammation may be induced. Previous studies showed that some commensal bacteria are detrimental while others have either no influence or have a protective action. In addition, each host has a genetically determined response to detrimental and protective bacterial species. These suggest that therapeutic manipulation of imbalance of microflora can influence health and disease. This review focuses on new insights into the role of commensal bacteria in gut health and disease, and presents recent findings in innate and adaptive immune interactions. Therapeutic approaches to modulate balance of intestinal microflora and their potential mechanisms of action are also discussed.

Bifidogenic growth stimulator for the treatment of active ulcerative colitis: a pilot study

OBJECTIVES

Experimental studies have shown that luminal antigens are involved in chronic intestinal inflammatory disorders. Bifidogenic growth stimulator (BGS) is a prebiotic preparation produced by Propionibacterium freudenreichii isolated from Swiss cheese. Previously BGS was shown to act in the colon as a growth stimulator of Bifidobacteria. This study investigated the efficacy and safety of BGS in the treatment of ulcerative colitis.

METHODS

Twelve patients with mildly to moderately active ulcerative colitis received orally 4.5 g of BGS daily for 4 wk in an open-label treatment protocol while the baseline anti-inflammatory therapy was continued. The response to treatment was evaluated clinically and endoscopically. Concentrations of short-chain fatty acids and the composition of commensal bacteria, including Bifidobacteria, Enterobacteria and Bacteroides species, were studied in stool samples.

RESULTS

Patients showed improvement in their clinical activity index scores, with a significant decrease in the score from 7.4 +/- 2.8 to 4.7 +/- 1.5 (mean +/- standard error of the mean, P < 0.01). The endoscopic index score decreased from 4.4 +/- 1.7 to 2.8 +/- 1.8 (P < 0.05) with treatment. Patients showed an increase in stool butyrate concentrations after BGS treatment (P < 0.05). There were no significant changes in stool levels of bacteria as a result of BGS treatment. No side effects related to BGS were observed.

CONCLUSIONS

Oral BGS therapy may represent a non-toxic way to treat ulcerative colitis. However, controlled studies are needed to demonstrate its efficacy in the treatment of this disorder.

Probiotic Lactobacillus-induced improvement in murine chronic inflammatory bowel disease is associated with the down-regulation of pro-inflammatory cytokines in lamina propria mononuclear cells

IL-6/STAT-3 signals play key roles in inflammatory bowel disease (IBD). It is known that Lactobacillus casei strain Shirota (LcS) improves inflammatory disorders. This study aimed to elucidate the effect of LcS on murine chronic IBD and to clarify the mechanism. We focused the inhibitory effect of LcS on the production of IL-6 in lipopolysaccharide (LPS)-stimulated large intestinal lamina propria mononuclear cells (LI-LPMC) isolated from mice with chronic colitis and in RAW264.7 cells in vitro. We also determined in vivo the effect of LcS on murine chronic IBD models induced with dextran sodium sulphate and SAMP1/Yit mice. Finally, we examined the cellular determinants of LcS for the down-regulation of IL-6 secretion by LI-LPMC, RAW264.7 cells and peripheral blood mononuclear cells (PBMC) derived from patients with ulcerative colitis (UC). LcS, but not other strains of Lactobacillus, inhibited the production of IL-6 in LPS-stimulated LI-LPMC and RAW264.7 cells, down-regulating the nuclear translocation of NF-kappaB. The LcS-diet-improved murine chronic colitis is associated with the reduction of IL-6 synthesis by LI-LPMC. LcS also improved chronic ileitis in SAMP1/Yit mice. The release of IL-6 in vitro in LPS-stimulated LI-LPMC, RAW 264.7 cells and UC-PBMC was inhibited by a polysaccharide-peptidoglycan complex (PSPG) derived from LcS. This probiotic-induced improvement in murine chronic inflammatory bowel disease is associated with the down-regulation of pro-inflammatory cytokines such as IL-6 and IFN-gamma production in LPMC. Therefore, LcS may be a useful probiotic for the treatment of human inflammatory bowel disease.

In vivo demonstration of T lymphocyte migration and amelioration of ileitis in intestinal mucosa of SAMP1/Yit mice by the inhibition of MAdCAM-1

The aetiology of Crohn's disease (CD) remains unknown. Since SAMP1/Yit mice have been reported to develop CD-like spontaneous enteric inflammation, such mice have been studied as an animal model of CD. In this study, using this model we examined T lymphocyte migration in microvessels of intestinal mucosa in vivo and the expression of adhesion molecules by immunohistochemistry. Fluorescence-labelled T lymphocytes isolated from AKR/J (control) mice were injected into the tail veins of recipient mice, and T lymphocyte migration in the postcapillary venules of Peyer's patches, submucosal microvessels, and villus capillaries of the terminal ileum was monitored using an intravital microscope. Adhesion of T lymphocytes was significantly increased in 35 week old SAMP1/Yit mice compared with that in AKR/J or 15 week old SAMP1/Yit mice. Immunohistochemical study showed increased infiltration of CD4, CD8 and beta7-integrin-positive cells and increased expression of MAdCAM-1 and VCAM-1 in the terminal ileum of SAMP1/Yit mice. Antibodies against MAdCAM-1 and VCAM-1 significantly inhibited adhesion of T lymphocytes to microvessels of the terminal ileum, and anti-MAdCAM-1 antibody showed stronger suppressive effect than the anti-VCAM-1 antibody. Periodical administration of anti-MAdCAM-1 antibody twice a week for 7 weeks significantly ameliorated ileitis of SAMP1/Yit mice, but submucosal hypertrophy was not significantly suppressed. Anti-VCAM-1 antibody treatment failed to show significant resolution of ileitis. In addition, anti-MAdCAM-1 antibody treatment also attenuated established ileitis. The results demonstrate that, although MAdCAM-1 and VCAM-1 play an important role in T lymphocyte-endothelial cell interactions in SAMP1/Yit mice, MAdCAM-1 may be a more appropriate target for therapeutic modulation of chronic ileitis.

Nonpathogenic Escherichia coli strain Nissle1917 prevents murine acute and chronic colitis

BACKGROUND

Nonpathogenic Escherichia coli strain Nissle1917 has been used as a probiotics in human inflammatory bowel disease; however, there are few reports examining its therapeutic effect on animal colitis models, and its therapeutic mechanisms remain unknown. The aim of this study was to elucidate the therapeutic effect and mechanism of Nissle1917 using murine acute and chronic colitis models.

METHODS

Two models were used. (1) Acute model: colitis was induced by administration of 1.3% dextran sodium sulfate for 7 days. Nissle1917 or phosphate-buffered saline were orally administered for 10 days. Mice were killed at day 10, and the colonic lesions were assessed macro- and microscopically. (2) Chronic model: IL-10 mice were treated with Nissle1917 or phosphate-buffered saline for 8 weeks. After 8 weeks of treatment, mice were killed to assess the colonic lesions macro- and microscopically. In the acute dextran sodium sulfate colitis model, viable, heat-killed, or genomic DNA of Nissle1917 was orally administered for 10 days, and the therapeutic effect was assessed.

RESULTS

In the acute model, Nissle1917 ameliorated body weight loss, disease activity index, and macro- and microscopic damage. In the chronic model, it also suppressed the mucosal inflammatory findings and histologic damages. Moreover, heat-killed Nissle1917 or its genomic DNA alone also ameliorated the acute DSS colitis and viable bacteria macro- and microscopically.

CONCLUSIONS

Nonpathogenic E. coli strain Nissle1917 prevents both acute and chronic colitis, and its anti-inflammatory effect is exhibited not only by viable bacteria but also by heat-killed bacteria or its DNA.

Antagonistic activities of lactobacilli and bifidobacteria against microbial pathogens

The gastrointestinal tract is a complex ecosystem that associates a resident microbiota and cells of various phenotypes lining the epithelial wall expressing complex metabolic activities. The resident microbiota in the digestive tract is a heterogeneous microbial ecosystem containing up to 1 x 10(14) colony-forming units (CFUs) of bacteria. The intestinal microbiota plays an important role in normal gut function and maintaining host health. The host is protected from attack by potentially harmful microbial microorganisms by the physical and chemical barriers created by the gastrointestinal epithelium. The cells lining the gastrointestinal epithelium and the resident microbiota are two partners that properly and/or synergistically function to promote an efficient host system of defence. The gastrointestinal cells that make up the epithelium, provide a physical barrier that protects the host against the unwanted intrusion of microorganisms into the gastrointestinal microbiota, and against the penetration of harmful microorganisms which usurp the cellular molecules and signalling pathways of the host to become pathogenic. One of the basic physiological functions of the resident microbiota is that it functions as a microbial barrier against microbial pathogens. The mechanisms by which the species of the microbiota exert this barrier effect remain largely to be determined. There is increasing evidence that lactobacilli and bifidobacteria, which inhabit the gastrointestinal microbiota, develop antimicrobial activities that participate in the host's gastrointestinal system of defence. The objective of this review is to analyze the in vitro and in vivo experimental and clinical studies in which the antimicrobial activities of selected lactobacilli and bifidobacteria strains have been documented.