Probiotics and the immune response

Evaluation of three fish-derived probiotic bacteria replacing antibiotics on growth, immunity, gut morphology and disease resistance in juvenile olive flounder Paralichthys olivaceus fed reduced fish meal diets

A basal diet without feed additives was used as a control (CON) and three diets were formulated by supplementing with Bacillus subtilis WB60 at 1 × 108 CFU/g (Pro-A), B. subtilis SJ10 at 1 × 108 CFU/g (Pro-B), Enterococcus faecium SH30 at 1 × 107 CFU/g (Pro-C), and two other diets supplementing with antibiotics such as amoxicillin (AMO) at 4 g/kg and oxytetracycline (OTC) at 4 g/kg of the basal diet. A total of 450 fish averaging 12.1 ± 0.09 g (mean ± SD) were fed one of the six experimental diet groups in triplicates for 8 weeks. In disease resistance test, 45 fish from each group were intraperitoneally injected with the pathogenic bacteria, Edwardsiella tarda, and mortality was recorded for 15 days. At the end of 8-week feeding trial, weight gain, specific growth rate and feed efficiency of fish fed the Pro-A diet were significantly greater than those of fish fed the CON, OTC and AMO diets (p < 0.05). Furthermore, feeding efficiency and protein efficiency ratio of fish fed the Pro-A diet were significantly greater than those of fish fed the CON, OTC and AMO diets. Serum aspartate aminotransferase levels were significantly greater in fish fed the Pro-B diet than in those fed the Pro-A diet. The lysozyme activity of fish fed the Pro-A, Pro-B and Pro-C diets was significantly greater than that of the CON, OTC and AMO diets. The myeloperoxidase activity of fish fed the Pro-A diet was significantly greater than that of the fish fed the CON and AMO diets. The flounder growth hormone levels of fish fed the Pro-A, Pro-B, Pro-C and AMO diets were significantly greater than that of the fish fed the CON diet. The interleukin 1β gene expression levels in fish fed the Pro-B and Pro-C diets were significantly greater than those in fish fed the CON, OTC and AMO diets. The interleukin 10 gene expression levels in fish fed the Pro-A, Pro-B, Pro-C and OTC diets were significantly greater than those of fish fed the CON and AMO diets. Intestinal histology revealed that the average villi length of fish fed the Pro-A, Pro-B, and Pro-C diets were significantly greater than that of fish fed the CON, OTC and AMO diets. The cumulative survival rates of fish fed the Pro-A, Pro-B and Pro-C diets were significantly greater than those of fish fed the CON diet after the 15th day of the challenge test. Overall, the results demonstrated that the supplementation of fish-derived bacteria, B. subtilis (1 × 108 CFU/g diet) or E. faecium (1 × 107 CFU/g diet) in the diet could be the ideal probiotics to replace antibiotics in olive flounder fed FM reduced diet.

Synbiotic effects of Lactobacillus plantarum CMT1 and Morinda citrifolia on the growth performance and disease resistance of whiteleg shrimp

This study assesses the effects of a prebiotic derived from Morinda citrifolia (noni fruit) extract and a probiotic of Lactobacillus plantarum CMT1 alone and in combination on the survival, growth performance, digestive enzymes, and disease resistance of whiteleg shrimp. A total of 1200 juvenile shrimp were randomly allocated to four treatments: control (not supplemented with noni fruit extract or L. plantarum CMT1), Treatment 1 (TRT1) (supplemented with 1 % noni fruit extract), Treatment 2 (TRT2) (supplemented with 108 CFU/kg L. plantarum CMT1), and Treatment 3 (TRT3) (supplemented with 1 % noni fruit extract and 108 CFU/kg L. plantarum CMT1). After 56 days of feeding, the growth indices of the TRT3 group were statistically larger than the other treatments (P < 0.05). Shrimp in the three treatment groups demonstrated significantly enhanced survival compared to those in the control group (P < 0.05), but no significant differences were observed among these three groups (P > 0.05). Shrimp fed the TRT3 diet had the lowest feed conversion rate, which was statistically significant compared to the other groups. Shrimp in the TRT3 group also had significantly higher amylase and protease levels than the control group. In addition, the use of fruit extract or L.plantarum CMT1 alone and in combination significantly increased shrimp survival after exposure to Vibrio parahaemolyticus, with the TRT3 group recording the highest value. The results indicate that a synbiotic of M. citrifolia extract and L.plantarum CMT1 could be used in shrimp aquaculture to promote animal development and health.

Integrating microbiome science and evolutionary medicine into animal health and conservation

Microbiome science has provided groundbreaking insights into human and animal health. Similarly, evolutionary medicine - the incorporation of eco-evolutionary concepts into primarily human medical theory and practice - is increasingly recognised for its novel perspectives on modern diseases. Studies of host-microbe relationships have been expanded beyond humans to include a wide range of animal taxa, adding new facets to our understanding of animal ecology, evolution, behaviour, and health. In this review, we propose that a broader application of evolutionary medicine, combined with microbiome science, can provide valuable and innovative perspectives on animal care and conservation. First, we draw on classic ecological principles, such as alternative stable states, to propose an eco-evolutionary framework for understanding variation in animal microbiomes and their role in animal health and wellbeing. With a focus on mammalian gut microbiomes, we apply this framework to populations of animals under human care, with particular relevance to the many animal species that suffer diseases linked to gut microbial dysfunction (e.g. gut distress and infection, autoimmune disorders, obesity). We discuss diet and microbial landscapes (i.e. the microbes in the animal's external environment), as two factors that are (i) proposed to represent evolutionary mismatches for captive animals, (ii) linked to gut microbiome structure and function, and (iii) potentially best understood from an evolutionary medicine perspective. Keeping within our evolutionary framework, we highlight the potential benefits - and pitfalls - of modern microbial therapies, such as pre- and probiotics, faecal microbiota transplants, and microbial rewilding. We discuss the limited, yet growing, empirical evidence for the use of microbial therapies to modulate animal gut microbiomes beneficially. Interspersed throughout, we propose 12 actionable steps, grounded in evolutionary medicine, that can be applied to practical animal care and management. We encourage that these actionable steps be paired with integration of eco-evolutionary perspectives into our definitions of appropriate animal care standards. The evolutionary perspectives proposed herein may be best appreciated when applied to the broad diversity of species under human care, rather than when solely focused on humans. We urge animal care professionals, veterinarians, nutritionists, scientists, and others to collaborate on these efforts, allowing for simultaneous care of animal patients and the generation of valuable empirical data.

Super Shedding in Enteric Pathogens: A Review

Super shedding occurs when a small number of individuals from a given host population shed high levels of a pathogen. Beyond this general definition, various interpretations of the shedding patterns have been proposed to identify super shedders, leading to the description of the super shedding phenomenon in a wide range of pathogens, in particular enteric pathogens, which are of considerable interest. Several underlying mechanisms may explain this observation, including factors related to the environment, the gut microbiota, the pathogen itself (i.e., genetic polymorphism), and the host (including immune factors). Moreover, data suggest that the interplay of these parameters, in particular at the host-pathogen-gut microbiota interface, is of crucial importance for the determination of the super shedding phenotype in enteric pathogens. As a phenomenon playing an important role in the epidemics of enteric diseases, the evidence of super shedding has highlighted the need to develop various control strategies.

Pharmacological Efficacy of Probiotics in Respiratory Viral Infections: A Comprehensive Review

Mortality and morbidity from influenza and other respiratory viruses are significant causes of concern worldwide. Infections in the respiratory tract are often underappreciated because they tend to be mild and incapacitated. On the other hand, these infections are regarded as a common concern in clinical practice. Antibiotics are used to treat bacterial infections, albeit this is becoming more challenging since many of the more prevalent infection causes have acquired a wide range of antimicrobial resistance. Resistance to frontline treatment medications is constantly rising, necessitating the development of new antiviral agents. Probiotics are one of several medications explored to treat respiratory viral infection (RVI). As a result, certain probiotics effectively prevent gastrointestinal dysbiosis and decrease the likelihood of secondary infections. Various probiotic bacterias and their metabolites have shown immunomodulating and antiviral properties. Unfortunately, the mechanisms by which probiotics are effective in the fight against viral infections are sometimes unclear. This comprehensive review has addressed probiotic strains, dosage regimens, production procedures, delivery systems, and pre-clinical and clinical research. In particular, novel probiotics' fight against RVIs is the impetus for this study. Finally, this review may explore the potential of probiotic bacterias and their metabolites to treat RVIs. It is expected that probiotic-based antiviral research would be benefitted from this review's findings.

The Use of Probiotic Therapy in Metabolic and Neurological Diseases

The human gut is home to trillions of microbes that interact with host cells to influence and contribute to body functions. The number of scientific studies focusing on the gut microbiome has exponentially increased in recent years. Studies investigating factors that may potentially affect the gut microbiome and may be used for therapeutic purposes in diseases where dysbioses in the gut microbiome have been shown are of particular interest. This review compiles current evidence available in the scientific literature on the use of probiotics to treat metabolic diseases and autism spectrum disorders (ASDs) to analyze the efficacy of probiotics in these diseases. To do this, we must first define the healthy gut microbiome before looking at the interplay between the gut microbiome and diseases, and how probiotics affect this interaction. In metabolic diseases, such as obesity and diabetes, probiotic supplementation positively impacts pathological parameters. Conversely, the gut–brain axis significantly impacts neurodevelopmental disorders such as ASDs. However, manipulating the gut microbiome and disease symptoms using probiotics has less pronounced effects on neurodevelopmental diseases. This may be due to a more complex interplay between genetics and the environment in these diseases. In conclusion, the use of microbe-based probiotic therapy may potentially have beneficial effects in ameliorating the pathology of various diseases. Validation of available data for the development of personalized treatment regimens for affected patients is still required.

Probiotics, Prebiotics and Postbiotics on Mitigation of Depression Symptoms: Modulation of the Brain-Gut-Microbiome Axis

The brain–gut–microbiome axis is a bidirectional communication pathway between the gut microbiota and the central nervous system. The growing interest in the gut microbiota and mechanisms of its interaction with the brain has contributed to the considerable attention given to the potential use of probiotics, prebiotics and postbiotics in the prevention and treatment of depressive disorders. This review discusses the up-to-date findings in preclinical and clinical trials regarding the use of pro-, pre- and postbiotics in depressive disorders. Studies in rodent models of depression show that some of them inhibit inflammation, decrease corticosterone level and change the level of neurometabolites, which consequently lead to mitigation of the symptoms of depression. Moreover, certain clinical studies have indicated improvement in mood as well as changes in biochemical parameters in patients suffering from depressive disorders.

Lozenges with probiotic strains enhance oral immune response and health

OBJECTIVE

Probiotics participate in regulating oral microbiota and reducing the prevalence of oral diseases; however, clinical research on probiotics is insufficient. Therefore, in this study, we performed in vitro screening of potential oral protective probiotic strains and then evaluated the clinical efficacy of the selected strains on maintaining oral health.

MATERIALS AND METHODS

Fifty healthy individuals were recruited and randomly assigned into the placebo group and probiotics group, which included three strains of probiotics, Lactobacillus salivarius subs. salicinius AP-32, Lactobacillus paracasei ET-66, and Lactobacillus plantarum LPL28. Each group was blindly administered placebo or probiotics for four weeks.

RESULTS

Next-generation sequencing results showed that the oral microbiota of Lactobacillus salivarius in the oral cavity were significantly increased in subjects supplemented with mixed probiotic lozenges. The anti-bacterial activities of viable probiotics were observed within two weeks. Both IgA levels and Lactobacillus and Bifidobacterium abundances in the oral cavity were significantly increased in the experimental groups, along with a reduced formation of plaque. Most participants reported that their oral health conditions and intestinal symptoms had improved.

CONCLUSIONS

Overall, our clinical study suggests that oral probiotic lozenges may enhance oral immunity, modulate oral microbiota, and improve oral health.

Memory T cells of patients with abdominal aortic aneurysm differentially expressed micro RNAs 21, 92a, 146a, 155, 326 and 663 in response to Helicobacter pylori and Lactobacillus acidophilus

Regarding the role of micro RNAs (miRNA) in the proliferation and differentiation of T cells as well as the controversy around the role of bacteria in the pathogenesis of abdominal aortic aneurysm (AAA), the effects of Helicobacter pylori (Hp) and Lactobacillus acidophilus (La) were investigated in the induction of miRNAs and apoptosis in CD4+ memory T (Tem) cells of AAA patients and controls. Signature atherosclerosis miRNAs 21, 92a, 146a, 155, 326 and 663 were measured in the sera and tissues of AAA patients and control. PBMCs separately and in co-culture with HUVEC were treated with Hp-water-extract (HpWE) and La-conditioned-medium (LaCM). Apoptosis and miRNA levels were assessed in the isolated Tem by flowcytometry and real-time-PCR. In single-culture, HpWE increased apoptosis and miR-155 and LaCM decreased apoptosis and increased miR-21. In co-culture, apoptosis decreased in both groups in response to CagA+HpWE. Also, all miRNAs increased in patients Tem but in controls, only miR- 146a and 21 showed changes. Although, apoptosis was similar in Tem of patients and controls, the effects of Hp and La were different on the induction of apoptosis and miRNAs and also these bacteria showed different impacts in single and co-culture conditions. Beyond the direct effects of these bacteria on the pathogenesis of diseases, their effects on miRNAs expression may shed light on their roles in the development and the prevention of AAA.

Effects of Queso Blanco cheese containing Bifidobacterium longum KACC 91563 on fecal microbiota, metabolite and serum cytokine in healthy beagle dogs

The study describes the effects of administration of Queso Blanco cheese containing Bifidobacterium longum on the fecal microbiota, metabolite and serum cytokine in healthy beagle dogs. Twelve healthy beagle dogs were randomly divided in three groups of four dogs each:a control group, not fed with any cheese, and groups fed with Queso Blanco cheese with B. longum KACC 91563 (QCB) or without B. longum (QC) for 8 weeks. Fecal microbiota was analyzed using a culture-based method and 16s rRNA gene sequencing. Serum cytokine levels, activation of natural killer cells, and proliferation of peripheral blood mononuclear cells were determined. SPME-GC-MS method was used to determine the concentrations of short chain fatty acids and indole in dog feces. Administration of QCB for 4 weeks significantly increased the Bifidobacterium. QCB supplementation for 8 weeks reduceds Enterobacteriaceae and Clostridium perfringens (p < 0.05). The abundance of Fusobacterium, Blautia and Collinesella in QCB group were reduced as compared with the control group. Serum TNF-α and IL-6 levels at 8 weeks significantly increased in QCB group as compared with QC group. There was no change in the concentrations of total short chain fatty acids by B. longum at 0 and 4 weeks. At week 8, the acetic acid, propionic acid and butyric acid of the QCB and QC groups were significantly decreased compared to the control group. In conclusion, our results demonstrate that administration of QCB had positive effects on fecal microbiota and immune response in beagle dogs. We suggest that Queso Blanco cheese containing B. longum KACC 91563 could be used as a functional food for companion animals.

Efficacy of synbiotic Jerusalem artichoke and Lactobacillus rhamnosus GG-supplemented diets on growth performance, serum biochemical parameters, intestinal morphology, immune parameters and protection against Aeromonas veronii in juvenile red tilapia (Oreochromis spp.)

Synbiotics, a synergistic combination of probiotics and prebiotics, are currently regarded as one of the most practical nutritional supplements in tilapia farms. In this study, the effect of supplementing the diet of red tilapia (Oreochromis spp.) with Jerusalem artichoke (Helianthus tuberosus) and Lactobacillus rhamnosus GG (LGG) was evaluated. Growth performance, serum biochemical parameters, intestinal morphology, goblet cell counts, immune parameters and protection against Aeromonas veronii challenge were determined. The results showed that fish fed with synbiotic-supplemented diets had a significantly higher (P < 0.05) feed conversion ratio (FCR), specific growth rate (SGR), and average daily gain (ADG) than fish fed with a control diet. The synbiotic-supplemented diet increased glucose, total protein and the total cholesterol levels. The absorptive area of the proximal and distal intestine of fish fed on the synbiotic diet was significantly higher (P < 0.05) than in those fed with probiotics (LGG), prebiotic-supplemented diets (JA), and the control diet. Goblet cell counts revealed that the numbers of acid mucous cells, neutral mucous cells and double-staining mucous cells of fish fed the synbiotic-supplemented diet (JA + LGG) were significantly higher (P < 0.05) in the proximal and distal intestine. Fish fed the synbiotic-supplemented diets also exhibited significantly higher (P < 0.05) lysozyme activity. The cumulative mortalities of fish fed with a synbiotic-supplemented diet were significantly lower than those of fish fed other diets. The results suggested the beneficial effect of JA and LGG synbiotic diet on growth performance and health status of red tilapia. Direct administration of JA and LGG in fish feed can be used as a practical nutritional supplement in red tilapia.

Yogurt consumption during pregnancy and preterm delivery in Mexican women: A prospective analysis of interaction with maternal overweight status

Preterm delivery is an important cause of perinatal morbidity and mortality, often precipitated by maternal infection or inflammation. Probiotic-containing foods, such as yogurt, may reduce systemic inflammatory responses. We sought to evaluate whether yogurt consumption during pregnancy is associated with decreased preterm delivery. We studied 965 women enrolled at midpregnancy into a clinical trial of prenatal docosahexaenoic acid supplementation in Mexico. Yogurt consumption during the previous 3 months was categorized as ≥5, 2-4, or <2 cups per week. Preterm delivery was defined as delivery of a live infant before 37 weeks gestation. We used logistic regression to evaluate the association between prenatal yogurt consumption and preterm delivery and examined interaction with maternal overweight status. In this population, 25.4%, 34.2%, and 40.4% of women reported consuming ≥5, 2-4, and <2 cups of yogurt per week, respectively. The prevalence of preterm delivery was 8.9%. Differences in preterm delivery were non-significant across maternal yogurt consumption groups; compared with women reporting <2 cups of yogurt per week, those reporting 2-4 cups of yogurt per week had adjusted odds ratio (aOR) for preterm delivery of 0.81 (95% confidence interval, CI [.46, 1.41]), and those reporting ≥5 cups of yogurt per week had aOR of 0.94 (95% CI [.51, 1.72]). The association between maternal yogurt consumption and preterm delivery differed significantly for nonoverweight women compared with overweight women (p for interaction = .01). Compared with nonoverweight women who consumed <2 cups of yogurt per week, nonoverweight women who consumed ≥5 cups of yogurt per week had aOR for preterm delivery of 0.24 (95% CI [.07, .89]). Among overweight women, there was no significant association. In this population, there was no overall association between prenatal yogurt consumption and preterm delivery. However, there was significant interaction with maternal overweight status; among nonoverweight women, higher prenatal yogurt consumption was associated with reduced preterm delivery.

Comparison of the effects of dietary single and multi-probiotics on growth, non-specific immune responses and disease resistance in starry flounder, Platichthys stellatus

An 8-week feeding trial was conducted to evaluate the effects of dietary probiotics on growth performance and non-specific immune responses in starry flounder, Platichthys stellatus. Fish averaging 46.5 ± 0.65 g (mean ± SD) were fed one of the six experimental diets; one control (Cont), and five other diets were prepared by supplementing single-probiotics 1 (Bacillus subtilis; SP₁, 2 × 10⁹ CFU kg^-1 diet), single-probiotics 2 (Bacillus licheniformis; SP₂, 2 × 10⁹ CFU kg^-1 diet), multi-probiotics 1 (Bacillus subtilis + Bacillus licheniformis; MP₁, 2 × 10⁹ CFU kg^-1 diet), multi-probiotics 2 (commercial probiotics; Bacillus subtills + Bacillus licheniformis + Paenibacillus polymyxa + Aspergillus oryzae + Saccharomyces cerevisiae; MP₂, 2 × 10⁹ CFU kg^-1 diet) and oxytetracycline (OTC) at 5 g OTC kg^-1 diet. At the end of 8 weeks feeding trial, weight gain (WG) and specific growth rate (SGR) of fish fed SP₁, MP₁ and MP₂ diets were significantly higher than those of fish fed control diet (P < 0.05). Superoxide dismutase (SOD) activity of fish fed MP₂ diet was significantly higher than those of fish fed OTC diet (P < 0.05). Nitro blue tetrazolium (NBT) activity and lysozyme activity of fish fed SP₁, MP₁ and MP₂ diets were significantly higher than those of fish fed OTC diet (P < 0.05). However, there was no significant difference among fish fed SP₁, SP₂, MP₁ and MP₂ diets. During the Edwardsiella tarda challenge test, the first mortality occurred on day 2. After the 14 days challenge test, cumulative survival rate of fish fed MP₁ and MP₂ diets were significantly higher than those of fish fed control diet (P < 0.05). However, there was no significant difference among fish fed SP₁, SP₂, MP₁, MP₂ and OTC diets in survival rate at the termination of the challenge test. Although there was little advantage in immunological parameters with fish fed MP diets, single and multi-probiotics were equally effective statistically. These results demonstrated that single or multi-probiotics had equal beneficial effect as an antibiotic replacer in terms of growth performance, non-specific immune responses and disease resistance in starry flounder.

Probiotic activity of Enterococcus faecalis CECT7121: effects on mucosal immunity and intestinal epithelial cells

AIMS

To analyse the effect of Enterococcus faecalis CECT7121 on intestinal epithelial cells (IECs) and its effects on the mucosal immune response.

METHODS AND RESULTS

Enterococcus faecalis CECT7121 showed a high adhesion capacity to completely and heterogeneously differentiated human intestinal epithelial cell line (Caco-2 cells). In addition, the contact of this bacterium with Caco-2 cells did not induce inflammatory chemokines (IL-8 and CCL-20). The presence of IgA(+) and IL-6(+) cells in the small intestine, as well as the production of inflammatory cytokines (TNFα, IL-6 and IL-12) in the gut, was determined after intragastric inoculation of Ent. faecalis CECT7121 in BALB/c mice. The administration of Ent. faecalis CECT7121 increased the number of IgA(+) cells in the intestinal lamina propria without modifying the percentage of IL-6(+) cells. No differences were observed in the cytokines measured in the intestinal extracts between probiotic-treated and control mice.

CONCLUSIONS

Enterococcus faecalis CECT7121 stimulates local mucosal immunity and adheres to IECs without inducing inflammatory signals.

SIGNIFICANCE AND IMPACT OF THE STUDY

Our results indicate that, apart from its already reported systemic immune activity, Ent. faecalis CECT7121 has a modulatory effect at a local level.

Intravaginal lactic Acid bacteria modulated local and systemic immune responses and lowered the incidence of uterine infections in periparturient dairy cows

The objective of this investigation was to evaluate whether intravaginal infusion of a lactic acid bacteria (LAB) cocktail around parturition could influence the immune response, incidence rate of uterine infections, and the overall health status of periparturient dairy cows. One hundred pregnant Holstein dairy cows were assigned to 1 of the 3 experimental groups as follows: 1) one dose of LAB on wk -2 and -1, and one dose of carrier (sterile skim milk) on wk +1 relative to the expected day of parturition (TRT1); 2) one dose of LAB on wk -2, -1, and +1 (TRT2), and 3) one dose of carrier on wk -2, -1, and +1 (CTR). The LAB were a lyophilized culture mixture composed of Lactobacillus sakei FUA3089, Pediococcus acidilactici FUA3138, and Pediococcus acidilactici FUA3140 with a cell count of 10⁸-10⁹ cfu/dose. Blood samples and vaginal mucus were collected once a week from wk -2 to +3 and analyzed for content of serum total immunoglobulin G (IgG), lipopolysaccharide-binding protein (LBP), serum amyloid A (SAA), haptoglobin (Hp), tumor necrosis factor (TNF), interleukin (IL)-1, IL-6, and vaginal mucus secretory IgA (sIgA). Clinical observations including rectal temperature, vaginal discharges, retained placenta, displaced abomasum, and laminitis were monitored from wk -2 to +8 relative to calving. Results showed that intravaginal LAB lowered the incidence of metritis and total uterine infections. Intravaginal LAB also were associated with lower concentrations of systemic LBP, an overall tendency for lower SAA, and greater vaginal mucus sIgA. No differences were observed for serum concentrations of Hp, TNF, IL-1, IL-6 and total IgG among the treatment groups. Administration with LAB had no effect on the incidence rates of other transition cow diseases. Overall intravaginal LAB lowered uterine infections and improved local and systemic immune responses in the treated transition dairy cows.

Immunomodulatory properties of cell wall extract from Enterococcus faecalis CECT7121

The aim of this study was to investigate the immunomodulatory properties of cell wall extract from Enterococcus faecalis CECT7121, measuring the induction of cytokines TNF-α, IL-6, IL-10 and IL-12 from human peripheral blood mononuclear cells (PBMCs). Cell wall extract was prepared from their growth in brain heart infusion broth (18 h, 35 °C). Subsequently, toxicity of the obtained cell wall extract was tested in Balb-C mice. PBMCs were isolated from buffy coats at the Blood Transfusion Service of Hospital Ramón Santamarina (Tandil, Argentina). PBMCs were purified using standard Ficoll-Paque gradient centrifugation. Aliquots of purified leukocytes were incubated at 37 °C for 24 h with heat-killed E. faecalis CECT7121 and cell wall extract. Concentrations of IL-6, TNFα, IL-10 and IL-12 (p70) were measured by solid phase sandwich ELISA. Changes in appearance and behavior of mice were evidenced only in the group with the maximal concentration of wall cell extract used (10,000 μg). Cell wall extract and heat-killed E. faecalis CECT7121 induced the production of significantly higher amounts of Il-12, IL-6, TNF-α and IL-10 cytokines compared to the nonstimulated PBMCs. These findings provide helpful information on immunomodulation activity by cell wall extract in sight of the application of this compound in controlling certain infectious diseases.

Immune response and intestinal permeability in children with acute gastroenteritis treated with Lactobacillus rhamnosus GG: a randomized, double-blind, placebo-controlled trial

BACKGROUND

Probiotics have a possible role in the treatment of pediatric acute gastroenteritis. We report the effect of the probiotic Lactobacillus rhamnosus GG (LGG) on intestinal function, immune response, and clinical outcomes in Indian children with cryptosporidial or rotavirus diarrhea.

METHODS

Children with gastroenteritis aged 6 months to 5 years, testing positive for either rotavirus or Cryptosporidium species in stool (coinfections were excluded), were randomized to LGG (ATCC 53103) or placebo, once daily for 4 weeks. Baseline demographic and clinical details were obtained. Sera were tested for immunoglobulin G (IgG) and immunoglobulin A (IgA) antibodies to Cryptosporidium and rotavirus, and the lactulose to mannitol ratio for intestinal permeability was determined at baseline and at the end of follow-up.

RESULTS

Of the 124 children enrolled, 82 and 42 had rotavirus and cryptosporidial diarrhea, respectively. Median diarrheal duration was 4 days; one-third of the children had severe diarrhea. Baseline and clinical parameters were comparable between children receiving LGG and placebo. At the end of follow-up, fewer children with rotavirus diarrhea on LGG had repeated diarrheal episodes (25% vs 46%; P = .048) and impaired intestinal function (48% vs 72%; P = .027). Significant increase in IgG levels postintervention (456 vs 2215 EU; P = .003) was observed in children with rotavirus diarrhea receiving LGG. Among children with cryptosporidial diarrhea, those receiving LGG showed significant improvement in intestinal permeability.

CONCLUSIONS

LGG has a positive immunomodulatory effect and may be useful in decreasing repeated episodes of rotavirus diarrhea. Improvement in intestinal function in children with rotavirus and cryptosporidial gastroenteritis emphasizes the role of probiotics in treating intestinal impairment after infection.

CLINICAL TRIALS REGISTRATION

CTRI/2010/091/000339.

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.

Cell-free culture supernatant of Bifidobacterium breve CNCM I-4035 decreases pro-inflammatory cytokines in human dendritic cells challenged with Salmonella typhi through TLR activation

Dendritic cells (DCs) constitute the first point of contact between gut commensals and our immune system. Despite growing evidence of the immunomodulatory effects of probiotics, the interactions between the cells of the intestinal immune system and bacteria remain largely unknown. Indeed,, the aim of this work was to determine whether the probiotic Bifidobacterium breve CNCM I-4035 and its cell-free culture supernatant (CFS) have immunomodulatory effects in human intestinal-like dendritic cells (DCs) and how they respond to the pathogenic bacterium Salmonella enterica serovar Typhi, and also to elucidate the molecular mechanisms involved in these interactions. Human DCs were directly challenged with B. breve/CFS, S. typhi or a combination of these stimuli for 4 h. The expression pattern of genes involved in Toll-like receptor (TLR) signaling pathway and cytokine secretion was analyzed. CFS decreased pro-inflammatory cytokines and chemokines in human intestinal DCs challenged with S. typhi. In contrast, the B. breve CNCM I-4035 probiotic strain was a potent inducer of the pro-inflammatory cytokines and chemokines tested, i.e., TNF-α, IL-8 and RANTES, as well as anti-inflammatory cytokines including IL-10. CFS restored TGF-β levels in the presence of Salmonella. Live B.breve and its supernatant enhanced innate immune responses by the activation of TLR signaling pathway. These treatments upregulated TLR9 gene transcription. In addition, CFS was a more potent inducer of TLR9 expression than the probiotic bacteria in the presence of S. typhi. Expression levels of CASP8 and IRAK4 were also increased by CFS, and both treatments induced TOLLIP gene expression. Our results indicate that the probiotic strain B. breve CNCM I-4035 affects the intestinal immune response, whereas its supernatant exerts anti-inflammatory effects mediated by DCs. This supernatant may protect immune system from highly infectious agents such as Salmonella typhi and can down-regulate pro-inflammatory pathways.

Modulation of the gut microbiota with antibiotic treatment suppresses whole body urea production in neonatal pigs

We examined whether changes in the gut microbiota induced by clinically relevant interventions would impact the bioavailability of dietary amino acids in neonates. We tested the hypothesis that modulation of the gut microbiota in neonatal pigs receiving no treatment (control), intravenously administered antibiotics, or probiotics affects whole body nitrogen and amino acid turnover. We quantified whole body urea kinetics, threonine fluxes, and threonine disposal into protein, oxidation, and tissue protein synthesis with stable isotope techniques. Compared with controls, antibiotics reduced the number and diversity of bacterial species in the distal small intestine (SI) and colon. Antibiotics decreased plasma urea concentrations via decreased urea synthesis. Antibiotics elevated threonine plasma concentrations and turnover, as well as whole body protein synthesis and proteolysis. Antibiotics decreased protein synthesis rate in the proximal SI and liver but did not affect the distal SI, colon, or muscle. Probiotics induced a bifidogenic microbiota and decreased plasma urea concentrations but did not affect whole body threonine or protein metabolism. Probiotics decreased protein synthesis in the proximal SI but not in other tissues. In conclusion, modulation of the gut microbiota by antibiotics and probiotics reduced hepatic ureagenesis and intestinal protein synthesis, but neither altered whole body net threonine balance. These findings suggest that changes in amino acid and nitrogen metabolism resulting from antibiotic- or probiotic-induced shifts in the microbiota are localized to the gut and liver and have limited impact on whole body growth and anabolism in neonatal piglets.

Probiotics in the critically ill: a systematic review of the randomized trial evidence

OBJECTIVE

Critical illness results in changes to the microbiology of the gastrointestinal tract, leading to a loss of commensal flora and an overgrowth of potentially pathogenic bacteria. Administering certain strains of live bacteria (probiotics) to critically ill patients may restore balance to the microbiota and have positive effects on immune function and gastrointestinal structure and function. The purpose of this systematic review was to evaluate the effect of probiotics in critically ill patients on clinical outcomes.

DESIGN

Systematic review.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

We searched computerized databases, reference lists of pertinent articles, and personal files from 1980 to 2011. We included randomized controlled trials enrolling critically ill adults, which evaluated probiotics compared to a placebo and reported clinically important outcomes (infections, mortality, and length of stay). A total of 23 randomized controlled trials met inclusion criteria. Probiotics were associated with reduced infectious complications as documented in 11 trials (risk ratio 0.82; 95% confidence interval 0.69-0.99; p = .03; test for heterogeneity p = .05; I 44%). When data from the seven trials reporting ventilator-associated pneumonia were pooled, ventilator-associated pneumonia rates were also significantly reduced with probiotics (risk ratio 0.75; 95% confidence interval 0.59-0.97; p = .03; test for heterogeneity p = .16; I 35%). Probiotics were associated with a trend toward reduced intensive care unit mortality (risk ratio 0.80; 95% confidence interval 0.59-1.09; p = .16; test for heterogeneity p = .89; I 0%) but did not influence hospital mortality. Probiotics had no effect on intensive care unit or hospital length of stay. Compared to trials of higher methodological quality, greater treatment effects were observed in trials of a lower methodological quality.

CONCLUSIONS

Probiotics appear to reduce infectious complications including ventilator-associated pneumonia and may influence intensive care unit mortality. However, clinical and statistical heterogeneity and imprecise estimates preclude strong clinical recommendations. Further research on probiotics in the critically ill is warranted.

The microbiome: the forgotten organ of the astronaut’s body – probiotics beyond terrestrial limits

Space medicine research has drawn immense attention toward provision of efficient life support systems during long-term missions into space. However, in extended missions, a wide range of diseases may affect astronauts. In space medicine research, the gastrointestinal microbiome and its role in maintaining astronauts’ health has received little attention. We would like to draw researchers’ attention to the significant role of microbiota. Because of the high number of microorganisms in the human body, man has been called a ‘supra-organism’ and gastrointestinal flora has been referred to as ‘a virtual organ of the human body’. In space, the lifestyle, sterility of spaceship and environmental stresses can result in alterations in intestinal microbiota, which can lead to an impaired immunity and predispose astronauts to illness. This concern is heightened by increase in virulence of pathogens in microgravity. Thus, design of a personal probiotic kit is recommended to improve the health status of astronauts.

Probiotics are effective for the prevention and treatment of Citrobacter rodentium-induced colitis in mice

BACKGROUND

Probiotics prevent disease induced by Citrobacter rodentium, a murine-specific enteric pathogen. Whether probiotics can be used to interrupt the infectious process following initiation of infection was determined.

METHODS

C57BL/6 adult and neonatal mice were challenged with C. rodentium, and a probiotic mixture containing Lactobacillus helveticus and Lactobacillus rhamnosus was provided 1 week before bacterial challenge, concurrently with infection, or 3 days and 6 days after infection. Mice were sacrificed 10 days after infection, and disease severity was assessed by histological analysis and in vivo intestinal permeability assay. Inflammatory pathways and the composition of the fecal microbiome were assessed in adult mice.

RESULTS

Preadministration and coadministration of probiotics ameliorated C. rodentium-induced barrier dysfunction, epithelial hyperplasia, and binding of the pathogen to host colonocytes in adults, with similar findings in neonatal mice. Upregulated tumor necrosis factor α and interferon γ transcripts were suppressed in the pretreated probiotic group, whereas interleukin 17 transcription was suppressed with probiotics given up to 3 days after infection. Probiotics promoted transcription of interleukin 10 and FOXP3, and increased follicular T-regulatory cells in pretreatment mice. C. rodentium infection resulted in an altered fecal microbiome, which was normalized with probiotic intervention.

CONCLUSIONS

This study provides evidence that probiotics can prevent illness and treat disease in an animal model of infectious colitis.

The anti-inflammatory role of granulocyte colony-stimulating factor in macrophage–dendritic cell crosstalk afterLactobacillus rhamnosusGR-1 exposure

MΦs are important sensory cells of the innate immune system and regulate immune responses through releasing different combinations of cytokines. In this study, we examined whether cytokines released by MΦs in response to the probiotic bacterial strain GR-1 modulate the responses of DCs. The cytokine profile released by GR-1-treated MΦs was characterized by low levels of TNF-α, GM-CSF, IL-6, and IL-12 but very high levels of G-CSF. GR-1 CM did not induce expression of the shared p40 subunit of IL-12 and IL-23 and costimulatory molecules CD80 or CD86 or increase T cell stimulatory capacity in DCs. However, in G-CSFR-deficient DCs or after antibody-mediated neutralization of G-CSF, GR-1 CM induced IL-12/23 p40 production significantly, indicating that G-CSF within the GR-1 CM inhibits IL-12/23 p40 production induced by other CM components. GR-1 CM and rG-CSF also inhibited LPS-induced IL-12 production at the mRNA and protein levels. The inhibition of IL-12 production by G-CSF was at least in part mediated through inhibition of JNK activation. Finally, splenic DCs of GR-1-injected mice produced less IL-12/23 p40 than those of PBS-injected mice in response to LPS ex vivo, and this was at least partially dependent on exposure to GR-1-induced G-CSF in vivo. Altogether, these results suggest that G-CSF modulates the IL-12/23 p40 response of DCs in the context of the probiotic GR-1 through MΦ–DC crosstalk.

Immunomodulatory impact of a synbiotic in T(h)1 and T(h)2 models of infection

BACKGROUND AND METHODS

The immunomodulatory activity of a synbiotic combination containing three bacterial strains (Lactobacillus helveticus R0052, Bifidobacterium longum subsp. infantis R0033 and Bifidobacterium bifidum R0071) and short-chain fructooligosaccharide was examined in two distinct infectious rat models. In the T(h)1 model, Wistar rats were administered the synbiotic combination for 2 weeks prior to challenge with a single oral dose of enterotoxigenic Escherichia coli or vehicle. In the T(h)2 model, pretreated rats were challenged with a single subcutaneous dose of hook worm, Nippostrongylus brasiliensis. Blood samples were collected 3 hours or 4 days postchallenge and serum levels of pro- and anti-inflammatory cytokines were measured.

RESULTS

Significant reductions in pro-inflammatory cytokines interleukin (IL)-1α, IL-1β, IL-6, and tumour necrosis factor (TNF)-α were observed in both models suggesting a single, unifying mode of action on an upstream regulator. The N. brasiliensis study also compared the effect of the individual strains to synbiotic. For most of cytokines the combination appeared to average the effect of the individual strains with the exception of IL-4 and IL-10 where there was apparent synergy for the combination. Furthermore, the cytokine response varied by strain.

CONCLUSIONS

It was concluded that this synbiotic combination of these three microbes could be beneficial in both T(h)1 and T(h)2 diseases.

Gut microbial diversity is reduced by the probiotic VSL#3 and correlates with decreased TNBS-induced colitis

BACKGROUND

Compositional changes within the normal intestinal microbiota have been associated with the development of various intestinal inflammatory disorders such as pouchitis and inflammatory bowel diseases (IBD). Therefore, it has been speculated that manipulation of a dysbiotic intestinal microbiota has the potential to restore microbial homeostasis and attenuate inflammation.

METHODS

We performed community composition analyses by terminal restriction fragment length polymorphism (T-RFLP) of the bacterial 16S ribosomal RNA gene to investigate the impact of the probiotic VSL#3 on colonic microbial community composition and development of trinitrobenzene sulfonic acid (TNBS)-induced colitis in rats.

RESULTS

TNBS-induced chronic colitis was significantly reduced in VSL#3-fed rats compared to controls (P < 0.05). T-RFLP analysis revealed distinct microbial communities at luminal versus mucosal sites. Within the luminal microbiota, chronic colitis was associated with an overall decrease in bacterial richness and diversity (Margalef's richness, P < 0.01; Shannon diversity, P < 0.01). This decrease in luminal microbial diversity was enhanced in TNBS-treated rats fed VSL#3 (Margalef's richness, P < 0.001; Shannon diversity, P < 0.001) and significantly correlated with reduced clinical colitis scores (Pearson correlation P < 0.05).

CONCLUSIONS

Our data demonstrate that the probiotic VSL#3 alters the composition of the intestinal microbiota and these changes correlate with VSL#3-induced disease protection.

Probiotic Bio-Three induces Th1 and anti-inflammatory effects in PBMC and dendritic cells

AIM: To investigate the immune response of peripheral blood mononuclear cells (PBMCs) and dendritic cells (DCs) that were stimulated by probiotic preparations.

METHODS: PBMCs were isolated, cultured, and stimulated with Bio-Three (a mixture of Bacillus mesentericus, Clostridium butyricum and Enterococcus faecalis; 10⁵, 10⁶ and 10⁷ CFU/mL for 24 h). Cytokine production of (1) circulating PBMCs; (2) PBMCs stimulated by probiotic preparation; (3) monocyte-derived DCs; and (4) DC and T cell co-culture was determined by enzyme-linked immunosorbent assay. Phenotypic analysis of circulating PBMCs was also investigated by flow cytometry. Blood was obtained from individuals who consumed Bio-Three (10⁹ CFU/d B. mesentericus, C. butyricum and E. faecalis) for 2 wk, or those who did not take probiotics orally.

RESULTS: In culture supernatants, interferon-γ (IFN-γ) and interleukin (IL)-10 production increased, but IL-4 and tumor necrosis factor-α (TNF-α) production by PBMCs decreased after 1 and 2 wk of probiotic treatment. Flow cytometry was also performed on day 14 and detected enhanced expression of CD11b, HLA-DR, CD4, CD45RA, CD25, CD44 and CD69 in response to Bio-Three. Furthermore, IL-10 and IL-12 were upregulated in supernatants of monocyte-derived DCs, and IFN-γ and IL-10 were enhanced in supernatants of CD4⁺ T cells co-cultured with DCs.

CONCLUSION: Bio-Three appeared to stimulate the Th1 immune response, downregulate pro-inflammatory cytokines (TNF-α) and upregulate anti-inflammatory cytokine (IL-10). Probiotics could be effective in activation of PBMCs and DCs.

Probiotics and immunity: a fish perspective

Probiotics are usually live microorganisms which when administered in adequate amounts confer a health benefits on host. Nowadays, probiotics are also becoming an integral part of the aquaculture practices to obtain high production. The common probiotics that are used for aquaculture practices include Lactobacillus, Lactococcus, Leuconostoc, Enterococcus, Carnobacterium, Shewanella, Bacillus, Aeromonas, Vibrio, Enterobacter, Pseudomonas, Clostridium, and Saccharomyces species. The involvement of probiotics in nutrition, disease resistance and other beneficial activities in fish has proven beyond any doubt. Among the numerous health benefits attributed to probiotics, modulation of immune system is one of the most commonly purported benefits of the probiotics and their potency to stimulate the systemic and local immunity under in vitro and in vivo conditions is noteworthy. Different probiotics either monospecies or multispecies supplementation can eventually elevate phagocytic, lysozyme, complement, respiratory burst activity as well as expression of various cytokines in fish. Similarly, probiotics can stimulate the gut immune system of fish with marked increase in the number of Ig(+) cells and acidophilic granulocytes. Furthermore, mono-bacterial association studies (with non-probiotic bacterial strains) in gnotobiotic fish also indicate the up-regulation of various immune related genes. Though the exact mode of action of probiotics is yet to be established in any animal including fish, probiotics often exert host specific and strain specific differences in their activities. Various factors like source, type, dose and duration of supplementation of probiotics can significantly affect the immunomodulatory activity of probiotics. The review is therefore, aiming to highlight the immunomodulatory activity of probiotics and also to evaluate the factors that regulate for the optimum induction of immune responses in fish.

Probiotics and ileitis: could augmentation of TNF/NFκB activity be the answer?

Probiotics have gained tremendous popularity amongst individuals searching for alternative and "natural" means to promote intestinal health. It has been suggested that the probiotic formulation VSL#3 promotes several aspects of intestinal health including attenuation of inflammatory bowel diseases (IBD). Although a definitive mechanism of action has not been clearly identified, it is generally accepted that probiotics suppress development of chronic inflammation by inhibiting activation of various inflammatory signaling pathways. This concept however needs to be revisited in light of a recent publication by Pagnini et al. showing that VSL#3 prevents development of ileitis through activation of NFκB and production of the prototypical inflammatory cytokine TNFα.

Oral Bifidobacterium modulates intestinal immune inflammation in mice with food allergy

BACKGROUND AND AIMS

It is proposed that probiotics have a therapeutic effect on the treatment of immune disorders. However, the underlying mechanisms require clarification. The present study aimed to evaluate the effect of gavage-feeding Bifidobacteria on suppression of T helper 2 (Th2) pattern inflammation in the intestines of mice with food allergy.

METHODS

Mice were sensitized to ovalbumin to induce the intestinal Th2 pattern inflammation. Allergic mice were treated with or without Bifidobacteria via gavage-feeding. Th2 response, number of regulatory T cells (Treg) in the spleen and intestine, intestinal epithelial barrier function and bifidobacterial translocation were examined.

RESULTS

The results showed that serum-specific immunoglobulin E antibody and interleukin 4 (IL-4) were increased in allergic mice. Intestinal epithelial barrier function was impaired in allergic mice as shown by the increase in epithelial ion secretion and permeability to macromolecular protein horseradish peroxidase in Ussing chambers. Number of Treg was decreased in both spleen and intestines of allergic mice. Gavage-feeding Bifidobacteria significantly suppressed the skewed Th2 response and increased the number of Treg. Transient bifidobacterial translocation was observed in allergic mice.

CONCLUSIONS

Oral administration of Bifidobacteria has the capacity to suppress the skewed Th2 response in allergic mice, increasing the number of Treg and IL-10-positive cells and improve the impaired intestinal epithelial barrier function.

Current level of consensus on probiotic science--report of an expert meeting--London, 23 November 2009

The present paper summarizes the consensus views of a group of 9 European clinicians and scientists on the current state of scientific knowledge on probiotics, covering those areas where there is substantial evidence for beneficial effects and those where the evidence base is poor or inconsistent. There was general agreement that probiotic effects were species and often strain specific. The experts agreed that some probiotics were effective in reducing the incidence and duration of rotavirus diarrhoea in infants, antibiotic-associated diarrhoea in adults and, for certain probiotics, Clostridium difficile infections. Some probiotics are associated with symptomatic improvements in irritable bowel syndrome and alleviation of digestive discomfort. Probiotics can reduce the frequency and severity of necrotizing enterocolitis in premature infants and have been shown to regulate intestinal immunity. Several other clinical effects of probiotics, including their role in inflammatory bowel disease, atopic dermatitis, respiratory or genito-urinary infections or H.pylori adjuvant treatment were thought promising but inconsistent.

Prevention of TNBS-induced colitis by different Lactobacillus and Bifidobacterium strains is associated with an expansion of gammadeltaT and regulatory T cells of intestinal intraepithelial lymphocytes

BACKGROUND

Probiotics may protect against inflammatory bowel disease through regulation of lamina propria lymphocytes (LPLs) function. Data are lacking on possible involvement of intraepithelial lymphocytes (IELs). The aim of this study was to investigate whether different probiotic mixtures prevented gut inflammatory disease and the role of both IELs and LPLs.

METHODS

BALB/c mice received 2 probiotic mixtures orally for 3 weeks, as Mix1 (Lactobacillus acidophilus and Bifidobacterium longum), or Mix2 (Lactobacillus plantarum, Streptococcus thermophilus, and Bifidobacterium animalis subsp. lactis). Colitis was induced by intrarectal administration of trinitrobenzene sulfonic acid (TNBS). Probiotics in stools were analyzed by real-time polymerase chain reaction (PCR). Colon subpopulations of IELs and LPLs were assayed by flow cytometry. Serum cytokines were measured by cytometric bead array (CBA).

RESULTS

All probiotics colonized the intestine. The 2 mixtures prevented the TNBS-induced intestinal damage, and Mix1 was the most effective. The Mix1 protection was associated with a reduction in CD4(+) cells of IELs and LPLs, an increase in gammadeltaT cells of IELs, and a decrease in gammadeltaT cells of LPLs. An expansion of T regulatory (Treg) cells of IELs was induced by Mix1 and Mix2. Both probiotic mixtures inhibited tumor necrosis factor (TNF)-alpha and monocyte chemotactic protein (MCP)-1 production and upregulated interleukin (IL)-10. In addition, Mix1 prevented the TNBS-induced increase of IL-12 and interferon (IFN)-gamma.

CONCLUSIONS

The 2 probiotic mixtures were able to prevent the TNBS-induced colitis; the L. acidophilus and B. longum mixture was the most effective. Other than an involvement of LPLs, our results report a novel importance of the IELs population in probiotic protection.

Toll-like receptor 2 ligands on the staphylococcal cell wall downregulate superantigen-induced T cell activation and prevent toxic shock syndrome

Staphylococcal superantigens are pyrogenic exotoxins that cause massive T cell activation leading to toxic shock syndrome and death. Despite the strong adaptive immune response induced by these toxins, infections by superantigen-producing staphylococci are very common clinical events. We hypothesized that this may be partly a result of staphylococcal strains having developed strategies that downregulate the T cell response to these toxins. Here we show that the human interleukin-2 response to staphylococcal superantigens is inhibited by the simultaneous presence of bacteria. Such a downregulatory effect is the result of peptidoglycan-embedded molecules binding to Toll-like receptor 2 and inducing interleukin-10 production and apoptosis of antigen-presenting cells. We corroborated these findings in vivo by showing substantial prevention of mortality after simultaneous administration of staphylococcal enterotoxin B with either heat-killed staphylococci or Staphylococcus aureus peptidoglycan in mouse models of superantigen-induced toxic shock syndrome.

Effects of FR-91 on immune cells from healthy individuals and from patients with non-Hodgkin lymphoma

The immune system is subject to destruction and dysfunction as a result of attacks by pathogenic and environmental agents. In addition, many clinical situations exist in which it is desirable to stimulate or suppress the immune system. The present study evaluated the screening efficacy of flow cytometric lymphocyte subset typing in peripheral blood mononuclear cells from healthy individuals (HI) and from patients with non-Hodgkin lymphoma (NHL) treated with different concentrations of FR-91, a standardized lysate of microbial cells belonging to the Bacillus genus, and in vitro cytokine production. Increased expression of subset markers (CD3, CD4, CD8) in NHL and CD3 in HI suggests an immunomodulating effect of FR-91. In addition the results of cytokine production also demonstrated a clear effect of FR-91 on both populations. A significant increase of IL-6, IL-12, IFN-gamma and TNF-alpha was observed in the HI group after treatment with FR-91. In a similar manner an increase of IL-2, IL-6, IL-12, IFN-gamma and TNF-alpha was also observed in the NHL group. In conclusion FR-91 seems to affect lymphocyte subpopulations, in vitro cytokine production, as well as mitogen-induced lymphocyte activation in a dose-dependent manner in both healthy individuals and NHL patients.

Effects of probiotics for the prevention and treatment of radiation-induced diarrhea

BACKGROUND AND AIMS

Probiotic supplementation seems to provide beneficial effects in the prevention and treatment of radiation-induced diarrhea. We performed a systematic review and meta-analysis to estimate the efficacy of probiotic supplementation for prevention and treatment of radiation-induced diarrhea.

METHODS

Two reviewers independently searched PubMed, EMBASE, Cochrane Library, Google Scholar and on-line clinical trials registers (up to January 2009) for randomized controlled trials that evaluated the efficacy of probiotic supplementation for the prevention and treatment of radiation-induced diarrhea. Each clinical trial was separately evaluated for study characteristics, methodologic quality and outcomes. Results of the randomized controlled trials were pooled in a meta-analysis.

RESULTS

Four randomized controlled trials were included. Three clinical trials, with a total of 632 subjects, evaluated the preventive effects of probiotic supplementation and 1 study evaluated the therapeutic role. Random effects meta-analysis of the preventive trials did not show significant differences between probiotic supplementation and control groups (odds ratio 0.47; 95% confidence interval: 0.13-1.67). However, the few available trials and the presence of significant clinical and statistical heterogeneity limited the analysis. Similarly, the therapeutic clinical trial did not show significant differences between active and placebo groups. No major adverse events owing to probiotic supplementation were reported in any study.

CONCLUSIONS

Probiotic supplementation showed beneficial effect in the prevention and treatment of radiation-induced diarrhea in experimental animal studies. Encouraging results have been observed in humans; however, the few available clinical studies do not allow firm conclusions. More well-performed, randomized placebo-controlled studies are needed.

Effects of Bifidobacterium animalis administered during lactation on allergic and autoimmune responses in rodents

Probiotics are promoted as being beneficial to health and positive effects on the immune system have been reported. Beneficial immune effects have been attributed to several mechanisms, including stimulating T helper 1 (Th1) immunity. To explore the effects of the probiotic Bifidobacterium animalis on Th1- and Th2-mediated immune responses, two different animal models representing either Th1- or Th2-mediated immune responses were used: a rat model for experimental autoimmune encephalomyelitis (EAE) (Th1) and a mouse model for respiratory allergy induced by ovalbumin (OVA) (Th2). B. animalis administration started when the mice or rats were 2 weeks old. Respiratory allergy or EAE were induced when the animals were 6-7 weeks old. In the allergy model, B. animalis modestly reduced the number of infiltrating eosinophils and lymphocytes in the lungs, but no effects on allergen-specific serum immunoglobulin E levels were found. Cytokine profiles assessed after culturing spleen cells with the mitogen concanvalin A (ConA) showed that B. animalis skewed the Th1/Th2 balance towards Th1 in females. However, allergen-induced cytokine production in females was not affected by B. animalis. In males, B. animalis significantly decreased ConA-induced interleukin-13 and a trend towards lower levels of OVA-induced Th2 cytokines. In the EAE model, B. animalis significantly reduced the duration of clinical symptoms by almost 2 days in males and improved the body weight gain during the experimental period compared with the control group. Our data show that B. animalis reduced several immune parameters in the allergy as well as in the autoimmunity model.

Reduced expression of basal and probiotic-inducible G-CSF in intestinal mononuclear cells is associated with inflammatory bowel disease

BACKGROUND

Granulocyte-colony stimulating factor (G-CSF) is a pleiotropic cytokine involved in the hematopoiesis of granulocytes, neuroprotection, and immunomodulation. Previously, we have shown that probiotic Lactobacillus rhamnosus GR-1 induces G-CSF production from bone marrow-derived macrophages. Whether this probiotic also induces G-CSF in intestinal mononuclear cells is unknown.

METHODS

G-CSF release in response to L. rhamnosus GR-1 was analyzed in isolated intestinal lamina propria mononuclear cells from inflammatory bowel disease (IBD) and non-IBD patients. The effects of G-CSF on proinflammatory cytokine production in human peripheral blood mononuclear cells and intestinal tissue from C57BL/6 wildtype and G-CSF receptor knockout mice was examined.

RESULTS

Normal mouse or human intestinal lamina propria cells constitutively express high levels of G-CSF, of which production was further enhanced by exogenous L. rhamnosus GR-1. However, cells obtained from IBD patients showed reduced G-CSF production under basal conditions and also lower production after exogenous GR-1 treatments. Intestinal tissue samples isolated from G-CSF receptor-deficient mice constitutively expressed higher levels of TNFalpha, IL-23, and IL-12 than those from wildtype mice, and pretreatment of G-CSF suppressed lipopolysaccharide (LPS)-induced IL-23 in human peripheral blood mononuclear cells.

CONCLUSIONS

These results suggest that high G-CSF production induced by commensals such as L. rhamnosus is important in maintaining normal immunological homeostasis in the intestine and defects in the production of G-CSF are associated with IBD.