Probiotics and down-regulation of the allergic response

Modulation of the Systemic Immune Response in Suckling Rats by Breast Milk TGF-β2, EGF and FGF21 Supplementation

Breast milk is a rich fluid containing bioactive compounds such as specific growth factors (GF) that contribute to maturation of the immune system in early life. The aim of this study was to determine whether transforming growth factor-β2 (TGF-β2), epidermal growth factor (EGF) and fibroblast growth factor 21 (FGF21), compounds present in breast milk, could promote systemic immune maturation. For this purpose, newborn Wistar rats were daily supplemented with these GF by oral gavage during the suckling period (21 days of life). At day 14 and 21 of life, plasma for immunoglobulin (Ig) quantification was obtained and spleen lymphocytes were isolated, immunophenotyped and cultured to evaluate their ability to proliferate and release cytokines. The main result was obtained at day 14, when supplementation with EGF increased B cell proportion to reach levels observed at day 21. At the end of the suckling period, all GF increased the plasma levels of IgG1 and IgG2a isotypes, FGF21 balanced the Th1/Th2 cytokine response and both EGF and FGF21 modified splenic lymphocyte composition. These results suggested that the studied milk bioactive factors, mainly EGF and FGF21, may have modulatory roles in the systemic immune responses in early life, although their physiological roles remain to be established.

Development of Swine's Digestive Tract Microbiota and Its Relation to Production Indices-A Review

Simple Summary

Proper cooperation between digestive system microbiota and the host is an important issue in maintaining proper health condition, and—in the case of farm animals—production indices. In the case of pigs, microbiota significantly affect production parameters such as meat quality, growth rate or improvement of immune response to infections. Understanding of pig digestive system microbiota and factors affecting this is an important issue. This may enable improvement of animal performance and stabilization of microbiota during their growth, reducing the risk of metabolic or systemic diseases.

Abstract

The development of research methods and tools related to microbiome investigation, as well as widened knowledge and awareness concerning the significance of microorganisms inhabiting mammalian organisms, has led to an increasing popularity of studies in this field. This review paper presents some issues related to the swine microbiome, its development starting from an early age of life and its status in adult animals, as well as factors affecting the microbiome in pigs. Attention is paid to the role of probiotics and prebiotics as alternatives to antibiotics in the context of post-weaning diarrhea treatment, and to the role of microorganisms inhabiting the digestive tract of pigs in performance indices formation. In veterinary and pork production practice, understanding of the swine microbiome and its relationships with the host organism may be useful in the prevention of some diseases and also in improvement of performance results of animals.

Lowering effect of viable Pediococcus pentosaceus QU 19 on the rise in postprandial glucose

In the present study, we investigated the glucose-decreasing action of lactic acid bacteria (LAB). The finding of this study could be helpful for people in controlling their blood sugar levels. The LAB candidate was isolated from a Japanese fermented food and identified as Pediococcus pentosaceus by an analysis of its genome sequence. Postprandial blood glucose elevation was investigated using oral starch tolerance tests in mice. Normal mice were fed starch and lyophilized cells of P. pentosaceus QU 19 at the same time. Even without pre-administration of P. pentosaceus QU 19, elevation of the blood glucose level was significantly suppressed by the intake of P. pentosaceus QU 19 at the same time as oral administration of starch. According to the results for its survival in simulated digestive juice and the reduction of blood glucose level in mice, P. pentosaceus QU 19 has potential hypoglycemic activity. In vitro measurements revealed that the glucose-decreasing action of P. pentosaceus QU 19 is probably caused by the glucose assimilation of the strain, not the inhibition of carbohydrate-splitting enzymes which has been reported for other LABs previously. These findings indicate that specific strains of LAB, especially P. pentosaceus QU 19, and foods fermented by LAB may be beneficial for people who must manage glucose ingestion.

Bacillus clausii as adjunctive treatment for acute community-acquired diarrhea among Filipino children: a large-scale, multicenter, open-label study (CODDLE)

Background

Diarrhea is among the main causes of pediatric mortality in the Philippines. Probiotics have been shown to be beneficial in the management of acute diarrhea. Accordingly, the aim of this population-based study was to assess the safety and effectiveness of Bacillus clausii as an adjunct to standard therapy in Filipino children with acute community-acquired diarrhea of viral origin or associated with antibiotic administration.

Methods

A total of 3178 patients (median age of 2 years) were enrolled in this open-label, multicenter, observational study, and were treated with one to two vials of Bacillus clausii in the following bacterial stains: O/C, SIN, N/R, and T (oral suspension of 2 billion spores per 5-mL vial) for 5 to 7 days. Diarrhea duration, number of stools per day, improvement in gastrointestinal symptoms, children’s overall acceptability of Bacillus clausii therapy, and safety and tolerability were assessed. Concomitant treatment with oral rehydration solutions (26.6%), zinc (23.9%), and antibiotics prescribed for conditions other than diarrhea (13.6%) was recorded during the study. All other probiotics and antidiarrheals were prohibited.

Results

Therapy with Bacillus clausii was well-tolerated, and the adverse event rate was very low (0.09%). All reported adverse events, which included vomiting, erythematous rashes and stool color change, were mild to moderate. In more than half of the per-protocol population (1535/2916; 52.6%), diarrhea was resolved within the first 3 days of treatment with Bacillus clausii. There was no significant difference (p = 0.297) in mean diarrhea duration between patients with either antibiotic-associated (3.3 ± 1.3 days) or viral diarrhea (3.4 ± 1.3 days). However, children who only received Bacillus clausii supplementation without zinc had a significantly shorter diarrhea duration (3.3 ± 1.3 days) compared to zinc-treated children (3.6 ± 1.6 days; p < 0.001). Bacillus clausii significantly reduced the mean number of stools per day, from 5.2 ± 2.0 stools at baseline to 1.2 ± 0.6 stools at study end (p < 0.001). Similarly, the proportion of patients with loose stools decreased from 81.6% at baseline to 9.2% at end of treatment period. Acceptability of Bacillus clausii therapy was high.

Conclusion

This study adds knowledge on the good safety profile and on the effectiveness of Bacillus clausii as an adjunct treatment for acute childhood diarrhea.

In vitro adhesion and anti-inflammatory properties of native Lactobacillus fermentum and Lactobacillus delbrueckii spp

AIMS

This study aimed at characterizing the adhesion and immune-stimulatory properties of native probiotic Lactobacillus fermentum (MCC 2759 and MCC 2760) and Lactobacillus delbrueckii MCC 2775.

METHODS AND RESULTS

Adhesion of the strains was assessed in Caco-2 and HT-29 cell lines. Expression of adhesion and immune markers were evaluated in Caco-2 cells by real-time qPCR. The cultures displayed >80% of adhesion to both cell lines and also induced the expression of mucin-binding protein (mub) gene in the presence of mucin, bile and pancreatin. Adhesion was mediated by carbohydrate and proteinaceous factors. The cultures stimulated the expression of inflammatory cytokines in Caco-2 cells. However, pro-inflammatory genes were down-regulated upon challenge with lipopolysaccharide and IL-10 was up-regulated by the cultures. Cell wall extract of L. fermentum MCC 2760 induced the expression of IL-6 by 5·47-fold, whereas crude culture filtrate enhanced the expression of IL-10 by 14·87-fold compared to LPS control.

CONCLUSIONS

The bacterial cultures exhibited strong adhesion and anti-inflammatory properties.

SIGNIFICANCE AND IMPACT OF THE STUDY

This is the first report to reveal the role of adhesion markers of L. fermentum and L. delbrueckii by qPCR. The strain-specific anti-inflammatory property of native cultures may be useful to alleviate inflammatory conditions and develop a target-based probiotic.

Characterization of the LP28 strain-specific exopolysaccharide biosynthetic gene cluster found in the whole circular genome of Pediococcus pentosaceus

We have previously isolated a lactic acid bacterium (LAB), Pediococcus pentosaceus LP28, from the longan fruit Euphoria longana. Since the plant-derived LAB strain produces an extracellular polysaccharide (EPS), in this study, we analyzed the chemical structure and the biosynthesizing genes for the EPS. The EPS, which was purified from the LP28 culture broth, was classified into acidic and neutral EPSs with a molecular mass of about 50 kDa and 40 kDa, respectively. The acidic EPS consisted of glucose, galactose, mannose, and N-acetylglucosamine moieties. Interestingly, since pyruvate residue was detected in the hydrolyzed acidic EPS, one of the four sugars may be modified with pyruvate. On the other hand, the neutral EPS consisted of glucose, mannose, and N-acetylglucosamine; pyruvate was scarcely detected in the polysaccharide molecule. As a first step to deduce the probiotic function of the EPS together with the biosynthesis, we determined the whole genome sequence of the LP28 strain, demonstrating that the genome is a circular DNA, which is composed of 1,774,865 bp (1683 ORFs) with a GC content of 37.1%. We also found that the LP28 strain harbors a plasmid carrying 6 ORFs composed of 5366 bp with a GC content of 36.5%. By comparing all of the genome sequences among the LP28 strain and four strains of P. pentosaceus reported previously, we found that 53 proteins in the LP28 strain display a similarity of less than 50% with those in the four P. pentosaceus strains. Significantly, 4 of the 53 proteins, which may be enzymes necessary for the EPS production on the LP28 strain, were absent in the other four P. pentosaceus strains and displayed less than 50% similarity with other LAB species. The EPS-biosynthetic gene cluster detected only in the LP28 genome consisted of 12 ORFs containing a priming enzyme, five glycosyltransferases, and a putative polysaccharide pyruvyltransferase.

Monitoring of Water Spectral Pattern Reveals Differences in Probiotics Growth When Used for Rapid Bacteria Selection

Development of efficient screening method coupled with cell functionality evaluation is highly needed in contemporary microbiology. The presented novel concept and fast non-destructive method brings in to play the water spectral pattern of the solution as a molecular fingerprint of the cell culture system. To elucidate the concept, NIR spectroscopy with Aquaphotomics were applied to monitor the growth of sixteen Lactobacillus bulgaricus one Lactobacillus pentosus and one Lactobacillus gasseri bacteria strains. Their growth rate, maximal optical density, low pH and bile tolerances were measured and further used as a reference data for analysis of the simultaneously acquired spectral data. The acquired spectral data in the region of 1100-1850nm was subjected to various multivariate data analyses - PCA, OPLS-DA, PLSR. The results showed high accuracy of bacteria strains classification according to their probiotic strength. Most informative spectral fingerprints covered the first overtone of water, emphasizing the relation of water molecular system to cell functionality.

Brain and liver fatty acid composition changes upon consumption of Lactobacillus rhamnosus LA68

Recent reports suggest that the metabolic activity of the enteric microbiota may influence the fatty acid composition of the host tissue. There are many studies dealing with the influence of lactobacilli on various pathological conditions, and some of the effects are strain-specific. This study was designed to test the effects of a particular Lactobacillus strain, Lactobacillus rhamnosus LA68 on fatty acid composition of the liver and the brain of C57BL/6 mice in the absence of an underlying pathological condition. Female mice were supplemented with live L. rhamnosus LA68 bacteria for the duration of 1 month. Serum biochemistry was analyzed and liver and brain fatty acid composition was assessed by gas-liquid chromatography. Significant changes in liver and brain fatty acid composition were detected. In the liver tissue we detected an increase in palmitoleic acid (p = 0.038), while in the brain compartment we found an increase in palmitic (p = 0.042), stearic (p = 0.017), arachidonic acid (p = 0.009) and docosahexaenoic acid (p = 0.004) for control versus experimental group. These results show discrete changes caused by LA68 strain consumption. Even short duration of administration of LA68 influences the fatty acid composition of the host which adds to the existing knowledge about Lactobacillus host interaction, and adds to the growing knowledge of metabolic intervention possibilities.

Diet for the prevention of asthma and allergies in early childhood: much ado about something?

In the last decades there has been an increase in allergic disease throughout the world, particularly in children. Attempts have been made to identify the causes of this "allergy epidemic" in environmental changes and changes in population hygiene, lifestyle, socioeconomic level, and eating habits that would exert epigenetic effects. Dietetic hypotheses have been mainly focussed in long-chain polyunsaturated fatty acids, vitamin D, antioxidants, Mediterranean diet, and fruits, vegetables and fish consumption. Although the data suggest a certain association between diet and the development of asthma/allergy, there is no evidence that diet has an impact upon the prevalence of such diseases after early infancy. If indeed there is such an impact, it is likely to be confined to the prenatal period and the first months of life - when it is still possible to modulate the development of the respiratory, digestive and immune systems. Thus, once the most appropriate preventive measures have been defined, these should be implemented during pregnancy and lactation. The existing scientific evidence is unable to recommend any primary preventive measure in the general population or in different population subgroups. Special or restrictive diets in pregnant or nursing women are not indicated. Exclusive breastfeeding for six months is questioned, since solid foods should begin to be introduced at around four months of age. Once the atopic process has started, no nutritional strategies have been found to be effective as secondary or tertiary preventive measures. Longitudinal studies in cohorts of pregnant women or newborn infants could help clarify these issues.

MyD88 associated ROS generation is crucial for Lactobacillus induced IL-12 production in macrophage

It is well known that some strains of lactic acid bacteria (LAB) can induce IL-12 which plays an important role in modulating immune responses. However, the mechanisms by which LAB induce IL-12 production remain unclear. Here, we examine the role of toll-like receptors (TLR's) and reactive oxygen species (ROS) in IL-12 production by LAB stimulated peritoneal macrophages. Our results indicate that a TLR is not necessary for IL-12 induction by LAB, whilst the universal adaptor protein, MyD88, is essential. Specific strains of LAB induced ROS that correlated with both the frequency of phagocytosis and IL-12 production. Reduction in IL-12 production by NADPH oxidase inhibitors or ROS scavengers demonstrates the crucial role of ROS in IL-12 induction. Interestingly, deficiency of TLR2, 4, 9 or MyD88 did not affect the phagocytosis of LAB strain KW3110, a potent IL-12 inducer, and ROS production was significantly reduced only in MyD88 deficient macrophages. These results suggest the existence of TLR-MyD88 independent LAB recognition and MyD88 related ROS induction mechanisms. We show here the importance of ROS for IL-12 induction and provide new insights into IL-12 induction by LAB.

Exposure to probiotic Lactobacillus acidophilus L-92 modulates gene expression profiles of epithelial Caco-2 cells

To understand host gastrointestinal response after exposure to probiotic Lactobacillus acidophilus L-92, microarray analysis of cultured epithelial Caco-2 cells was performed. Of the 187 genes down-regulated after 4 h treatment with L-92, 25 were involved in RNA splicing; 12, in cell cycle; 8 were transcriptional regulators; 2 were involved in ubiquitin proteolysis; 2, in adhesion; 2, in meiosis; 2, in splicing; and 2 encoding cytokines. In the RNA splicing group, genes encoding small nuclear RNAs, nuclear pore complex interacting proteins, RNA binding motif proteins, and SMG1 homologs (phosphatidylinositol 3-kinase-related kinase) were identified. Among the only 13 genes up-regulated by the treatment, 5 were involved in histone structure, and 2 were involved in metabolism. Genes belonging to cell adhesion, transmembrane proteins, mitogen-activated protein kinase, immune response, DNA binding, inflammation, and protein synthesis groups were mainly up-regulated after 20 h of treatment, whereas no significantly down-regulated genes were observed. In the present transcriptome analysis, during the early stage of treatment (four hours of treatment) with L-92, genes involved in cell growth and cell meiosis were mainly repressed. During the late phase of treatment (20 h of treatment), the expression of the genes linked to cell adhesion activity and metabolism for cell growth was enhanced. From the present transcriptome analysis, we suggest that Caco-2 cells slow down cell death and turnover of RNA synthesis as an early response to L-92 treatment; at the late stage of treatment, the genes involved in cell proliferation, transcriptional activity, and apoptosis are activated.

Protective effect of probiotics on intestinal barrier function in malnourished rats after liver transplantation

BACKGROUND

Most patients waiting for liver transplantation have end-stage liver diseases with malnutrition, which is prone to induce intestinal barrier dysfunction after liver transplantation. We aimed to study the effect of probiotics on intestinal barrier function in malnourished rats following liver transplantation with long-term antibiotics.

METHODS

Twelve Lewis rats were selected as donors. Twelve BN rats, which served as recipients, were subjected to malnutrition by semi-starvation for 4-5 weeks. They were randomly divided into two groups: a control group which received phosphate-buffered saline and a probiotics group which received Bifidobacterium and Lactobacillus. All recipients were injected with intramuscular imipenem and subcutaneous cyclosporine A. Furthermore, six normal BN rats without any drugs or operations served as a normal group. Eight days after operation, all rats were sacrificed for examination of the following parameters: serum levels of endotoxin and TNF-alpha, bacterial translocation, intestinal microflora, ileocecal sIgA, lymphocyte numbers, and phenotypes (CD4, CD8, alphabetaTCR, gammadeltaTCR) of Peyer's patches.

RESULTS

In recipients subjected to malnutrition, weight decreased by 20% and they survived until 8 days after operation. Compared with the normal group, all recipients on postoperative day 8 showed increased levels of serum endotoxin and TNF-alpha as well as increased counts of translocated bacteria. Meanwhile, there were decreases in counts of Bifidobacterium and Lactobacillus in the ileocecum, sIgA concentration, and lymphocytes of Peyer's patches. Moreover, partial alteration in lymphocyte phenotypes was evidenced by elevated ratios of CD8+ and gammadeltaTCR+ lymphocytes. In contrast, compared to the control group, supplementation with probiotics reduced the levels of serum endotoxin, TNF-alpha and bacterial translocation, increased the counts of Bifidobacterium and Lactobacillus, the concentration of sIgA and lymphocytes of Peyer's patches, and also slightly restored the alteration of lymphocyte phenotypes.

CONCLUSION

Supplementation with probiotics including Bifidobac-terium and Lactobacillus promoted partial restoration of intestinal microflora and improved intestinal barrier function in malnourished rats after liver transplantation with long-term use of antibiotics.

Well-controlled proinflammatory cytokine responses of Peyer's patch cells to probiotic Lactobacillus casei

SUMMARY

In order to clarify the probiotic features of immunomodulation, cytokine production by murine spleen and Peyer's patch (PP) cells was examined in response to probiotic and pathogenic bacteria. In spleen cells, probiotic Lactobacillus casei induced interleukin (IL)-12 production by CD11b(+) cells more strongly than pathogenic Gram-positive and Gram-negative bacteria and effectively promoted the development of T helper (Th) type 1 cells followed by high levels of secretion of interferon (IFN)-gamma. Although the levels of IL-12 secreted by PP cells in response to L. casei were lower in comparison with spleen cells, Th1 cells developed as a result of this low-level induction of IL-12. However, IFN-gamma secretion by the L. casei-induced Th1 cells stimulated with a specific antigen was down-regulated in PP cells. Development of IL-17-producing Th17 cells was efficiently induced in PP cells by antigen stimulation. Lactobacillus casei slightly, but significantly, inhibited the antigen-induced secretion of IL-17 without a decrease in the proportion of Th17 cells. No bacteria tested induced the development of IL-10-producing, transforming growth factor-beta-producing or Foxp3-expressing regulatory T cells, thus suggesting that certain probiotics might regulate proinflammatory responses through as yet unidentified mechanisms in PP cells. These data show probiotic L. casei to have considerable potential to induce IL-12 production and promote Th1 cell development, but the secretion of proinflammatory cytokines such as IL-12 and IL-17 may be well controlled in PP cells.

Beneficial effect of a diet containing heat-killed Lactobacillus paracasei K71 on adult type atopic dermatitis

The purpose of this study was to investigate the clinical effect of a supplementary diet containing heat-killed lactic acid bacterium Lactobacillus paracasei K71 (LAB diet) on adult patients with atopic dermatitis (AD). A randomized, double-blind, placebo-controlled study was conducted in 34 adult type AD subjects who were treated with conventional topical corticosteroid and tacrolimus. LAB diet or placebo was added over 12 weeks. The primary end-point was the clinical severity of AD which was evaluated by a severity scoring system proposed by the guideline of the Japanese Dermatological Association. The effect was also secondarily evaluated by itch scores of visual analog scales (VAS), quality-of-life (QOL) impairment scores of Skindex 16 and consumption amounts of topical therapeutics. Data on these four assessment variables were collected at baseline and at week 4, 8 and 12. Within the study population, the skin severity scores were significantly decreased from baseline at week 8 (P<0.05) and at week 12 (P<0.01) in the LAB diet group but not in the placebo group. Influence of LAB diet on itch scores or QOL impairment scores was not evident. The consumption of topical therapeutics in the placebo group was 1.9-times greater in total amount compared with the corresponding value in the LAB diet group during the intervention period, although there was no significant difference. No LAB diet- or placebo-related adverse events were observed. We concluded that the LAB diet may have some benefits as a complementary therapy for adult AD patients who are managed with the conventional treatment.

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.

Orally administered Lactobacillus paracasei KW3110 induces in vivo IL-12 production

Lactic acid bacteria (LAB) are popularly used as probiotics, and some strains of LAB have anti-allergic functions in vivo. Although in vitro studies show that LAB modulate the T helper type (Th) 1/Th2 balance and inhibit IgE secretion by inducing IL-12, it is not known how LAB regulates allergies in vivo. In this study, we evaluated in vivo IL-12 production after oral administration of Lactobacillus paracasei KW3110, a strain reported to improve allergies, to mice. Orally administered KW3110 interacted with CD11b positive cells and induced IL-12 mRNA expression at Peyer's patch. In addition, blood IL-12 levels increased transiently 10 h after administration of KW3110. Based on these results, we found that oral administration of KW3110 induces IL-12 in vivo. Our findings should contribute to understanding of the in vivo function of LAB.

Probiotics as adjunctive treatment for chronic rhinosinusitis: A randomized controlled trial

Objective: To determine if oral probiotics as adjunctive treatment are more effective than placebo in improving quality of life in patients with chronic inflammatory rhinosinusitis.

Design: Prospective, randomized, double-blind, placebo-controlled trial.

Methods: A total of 77 patients with chronic inflammatory rhinosinusitis were randomly assigned to receive oral probiotic Lactobacillus rhamnosus R0011 strain (500 million active cells/tablet twice daily) (n = 39) or oral placebo treatment (n = 38) for 4 weeks.

Results: In the probiotic group, the mean change from baseline in the SNOT-20 scores was significant at 4 weeks ( P = 0.002) but not at 8 weeks ( P = 0.37). Rhinological domain improved by 9.3 percent ( P = 0.004) in probiotics group but returned to baseline level at 8 weeks. No significant differences were found between the probiotic and placebo groups in mean changes from baseline to 4 weeks ( P = 0.79) or from baseline to 8 weeks ( P = 0.23). No changes in symptom frequency were noted, either within each group or between treatment groups at 4 and 8 weeks. There was no difference in medication use or side effects between the two study groups.

Conclusion: Oral use of the probiotic strain L rhamnosus R0011 did not improve sinonasal quality-of-life scores in patients with chronic inflammatory rhinosinusitis compared with placebo.

Antibiotics and allergic disorders in childhood

AIM

This paper explores the possible association between antibiotics prescribed in infancy and allergic disorders, mainly eczema and asthma, in childhood.

BACKGROUND

No-one fully understands why childhood asthma and eczema have become so common. Some authorities suggest that there may be an association between eczema and asthma and antibiotics prescribed in childhood; however, others disagree. METHOD/EVALUATION: The available literature was reviewed to examine the links between prescribed antibiotics and childhood eczema and asthma. FINDINGS/KEY ISSUE: Some, but not all, research indicates that antibiotic administration in pregnancy, childbirth or infancy may be linked to childhood asthma and eczema, but much uncertainty remains. None of the papers identified stated the doses of antibiotics prescribed. In addition, we were unable to locate studies reporting the interactions between antibiotics and the developing immune system.

CONCLUSION

Health care professionals should be selective when prescribing antibiotics. Further prospective work is needed to guide the prescribing of antibiotics in childbirth and infancy.

Consumption of functional fermented milk containing borage oil, green tea and vitamin E enhances skin barrier function

As emerging studies show that skin functioning can be improved with orally imbibed ingredients, we decided to investigate a mixture of borage oil, catechins, vitamin E and probiotics, all known for their reported effects on epidermal function, in a fermented dairy product, for the first time. Gamma-linolenic acid (GLA) and catechins bioavailability and their effects on skin functionality have not been previously investigated from a fermented dairy product. Firstly, we assessed the bioavailability of GLA and catechins mixed in a fermented dairy matrix by measuring their levels in chylomicrons and plasma samples respectively. For the GLA contained in the dairy matrix, the area under the curve and time for maximal absorption were significantly different to the same kinetic parameters compared with absorption from the free oil indicating improved oral bioavailability. However, the overall absorption of catechins over the 6-h period was identical for both product forms. These results were sufficiently promising to warrant a 24 week skin nutrition intervention study in female volunteers having dry and sensitive skin. The product improved stratum corneum barrier function compared with a control product as early as 6 weeks after the consumption which continued throughout the rest of the study. The reduction in transepidermal water loss relative to control was maintained throughout the trial despite seasonal changes. Moreover, as a result of the enhanced bioavailability, a much greater effect on skin barrier function occurred than reported previously for the individual ingredients. Nevertheless, body mass index significantly influenced various outcome measurements of this study.

Prevalence and associated factors of allergic rhinitis and atopic dermatitis in children

Allergic disorders are the chronic diseases of greatest pediatric morbidity, affecting over 25 % of the pediatric population. Indeed, this situation has been referred to as an "allergic epidemic". In comparison with asthma, atopic dermatitis and allergic rhinitis have been less extensively investigated, although this does not mean that they should be regarded as minor disorders but rather as alterations that affect the quality of life of the patients and their families, which generate considerable direct and indirect costs. Despite an important research effort, the reason for this allergic epidemic is not well known. These are multifactor disorders without a single causal agent, in which the most important component is the genetic predisposition of the patient (atopy), modulated by environmental factors, exposure to allergens, infections and irritants, among others. A confounding element is the fact that the concept of allergic diseases encompasses phenotypes of rhinitis, atopic dermatitis or asthma in which no IgE-mediated atopic mechanism is demonstrated, and which can manifest in a way similar to true allergic phenotypes. Differentiation between the two is difficult to establish on the basis of self-administered questionnaires alone, in the absence of a precise etiological diagnosis. The present article reviews the numerous factors suggested to be responsible for the increase in allergic diseases recorded in the last few decades, and for the differences in prevalence observed among centres. For most of these factors the results published in the literature are contradictory, in some cases due to a lack of control of the associated interacting or confounding factors. Consensus exists for only some of these causal factors, such as the established parallelism between the increase in allergic diseases and the reduction in infectious processes on one hand, and the increase in particles generated by diesel fuel combustion on the other. In addition, the implicated factors could act differently (and in some cases even antagonically) upon atopy and on the different disease phenotypes, thereby complicating the study of these interactions even further.

Probiotic bacteria change Escherichia coli-induced gene expression in cultured colonocytes: Implications in intestinal pathophysiology

AIM: To investigate the change in eukaryotic gene expression profile in Caco-2 cells after infection with strains of Escherichia coli and commensal probiotic bacteria.

METHODS: A 19200 gene/expressed sequence tag gene chip was used to examine expression of genes after infection of Caco-2 cells with strains of normal flora E. coli, Lactobacillus plantarum, and a combination of the two.

RESULTS: The cDNA microarray revealed up-regulation of 155 and down-regulation of 177 genes by E. coli. L. plantarum up-regulated 45 and down-regulated 36 genes. During mixed infection, 27 genes were up-regulated and 59 were down-regulated, with nullification of stimulatory/inhibitory effects on most of the genes. Expression of several new genes was noted in this group.

CONCLUSION: The commensal bacterial strains used in this study induced the expression of a large number of genes in colonocyte-like cultured cells and changed the expression of several genes involved in important cellular processes such as regulation of transcription, protein biosynthesis, metabolism, cell adhesion, ubiquitination, and apoptosis. Such changes induced by the presence of probiotic bacteria may shape the physiologic and pathologic responses they trigger in the host.

Quantitative evaluation of adhesion of lactobacilli isolated from human intestinal tissues to human colonic mucin using surface plasmon resonance (BIACORE assay)

AIMS

To isolate lactobacilli from the mucus layer of the human intestine and evaluate their adhesion abilities using a BIACORE assay.

METHODS AND RESULTS

Thirty strains of lactobacilli were isolated from the mucus layer of normal human intestinal tissues using conventional plate culture. The strains were identified using homology comparisons of the 16S rDNA sequence to databases as Lactobacillus salivarius (26%), Lactobacillus fermentum (13%), Lactobacillus gasseri (10%), Lactobacillus paracasei (7%), Lactobacillus casei (3%), Lactobacillus mucosae (3%) and Lactobacillus plantarum (3%). Lactobacillus plantarum LA 318 shows the highest adhesion to human colonic mucin (HCM) using the BIACORE assay at 115.30 +/- 12.37 resonance unit (RU). The adhesion of cell wall surface proteins from strain LA 318 was significantly higher to HCM than to bovine serum albumin (BSA; P < 0.05).

CONCLUSIONS

We isolated 30 strains of lactobacilli. Lactobacillus salivarius was the predominant species of lactobacilli isolated in this study. The adhesion of strain LA 318 isolated from human transverse colon to its mucin was shown. The adhesion could be mediated by lectin-like components on the bacterial cell surface.

SIGNIFICANCE AND IMPACT OF THE STUDY

This is the first study where lactobacilli were isolated from human intestinal tissues and shown to adhere to HCM.

A randomized prospective double blind controlled trial on effects of long-term consumption of fermented milk containing Lactobacillus casei in pre-school children with allergic asthma and/or rhinitis

To examine whether long-term consumption of fermented milk containing a specific Lactobacillus casei may improve the health status of preschool children suffering from allergic asthma and/or rhinitis a randomized, prospective, double blind, controlled trial was conducted in 187 children 2-5 y of age. The children received for 12 mo either fermented milk (100 mL) containing Lactobacillus casei (10(8) cfu/mL) or placebo. The time free from and the number of episodes of asthma/rhinitis after starting intervention were the outcome measures. The number of fever or diarrhea episodes and the change in serum immunoglobulin were further assessed. No statistical difference between intervention and control group occurred in asthmatic children. In children with rhinitis, the annual number of rhinitis episodes was lower in the intervention group, mean difference (95% CI), -1.6 (-3.15 to -0.05); the mean duration of an episode of diarrhea was lower in the intervention group, mean difference -0.81 (-1.52 to -0.10) days. While long-term consumption of fermented milk containing Lactobacillus casei may improve the health status of children with allergic rhinitis no effect was found in asthmatic children.

Isolation and characterisation of new putative probiotic bacteria from human colonic flora

The present study describes a novel bacterial isolate exhibiting high ability to synthesise and secrete butyrate. The novel isolated bacterium was obtained from human faeces and grown in selective liquid intestinal microflora medium containing rumen fluid under microaerobic conditions. Its probiotic properties were demonstrated by the ability of the isolate to survive high acidity and medium containing bile acids and the ability to adhere to colon cancer cells (Caco-2) in vitro. Phylogenetic identity to Enterococcus durans was established using specific primers for 16S rRNA (99% probability). PCR analyses with primers to the bacterial gene encoding butyrate kinase, present in the butyrogenic bacteria Clostridium, showed that this gene is present in E. durans. The in vivo immunoprotective and anti-inflammatory effects of E. durans were assessed in dextran sodium sulfate (DSS)-induced colitis in Balb/c mice. Administration of E. durans ameliorated histological, clinical and biochemical scores directly related to intestinal inflammation whereas the lactic acid bacterium Lactobacillus delbrueckii was ineffective in this regard. Colonic cDNA concentrations of IL-1beta and TNF-alpha were significantly down regulated in DSS-treated E. durans-fed mice but not in control or DSS-treated L. delbrueckii- fed mice. Fluorescent in situ hybridisation analyses of colonic tissue from mice fed E. durans, using a butyrate kinase probe, demonstrated that E. durans significantly adheres to the colonic tissue. The novel isolated bacterium described in the present paper, upon further characterisation, can be developed into a useful probiotic aimed at the treatment of patients suffering from ulcerative colitis.

Clinical efficacy of probiotic Bifidobacterium longum for the treatment of symptoms of Japanese cedar pollen allergy in subjects evaluated in an environmental exposure unit

BACKGROUND

Japanese cedar pollinosis (JCPsis) affects nearly one in six Japanese. Oral administration of Bifidobacterium longum BB536 has been shown to be effective in relieving JCPsis symptoms during the pollen season.

METHODS

This double- two-way crossover study was designed to evaluate the efficacy of BB536 on reducing symptoms in JCPsis patients exposed to Japanese cedar pollen (JCP) in an environmental exposure unit (EEU) outside of the normal JCP season. After a 1-week run-in period, subjects (n=24) were randomly allocated to receive BB536 powder (approximately 5x1010) or placebo twice a day for 4 weeks. After a 2-week washout period, subjects were crossed over to another 4 weeks of intake. At the end of each intake period, subjects received controlled JCP exposure for 4 hours in the EEU. Symptoms were self-rated 30 minutes before and every 30 minutes during the exposures. From the first day of exposure through the next 5 successive days, participants self-rated their delayed symptoms and medication uses. Blood samples were taken before the exposures. The mean JCP levels for exposures were 6500 to 7000 grains/m3 air.

RESULTS

In comparison with placebo, BB536 intake significantly reduced the ocular symptom scores during JCP exposures. Evaluating delayed symptoms after exposures indicated that scores for disruption of normal activities were significantly lower in the BB536 group compared with the placebo group. Prevalence of medication use was markedly reduced by BB536 intake.

CONCLUSIONS

These results suggest the potential beneficial effect of BB536 in relieving symptoms of JCP allergy.

Essential roles of monocytes in stimulating human peripheral blood mononuclear cells with Lactobacillus casei to produce cytokines and augment natural killer cell activity

We examined the effect of a probiotic strain, Lactobacillus casei strain Shirota, on cytokine production and natural killer (NK) cell activity in human peripheral blood mononuclear cells (PBMNC). The cellular mechanisms of immunoregulation by L. casei strain Shirota were also investigated. L. casei strain Shirota stimulated PBMNC to secrete interleukin-12 (IL-12), gamma interferon (IFN-gamma), tumor necrosis factor alpha (TNF-alpha), and IL-10. However, depletion of monocytes from PBMNC eliminated the induction of these cytokines. L. casei strain Shirota was phagocytosed by monocytes and directly stimulated them to secrete IL-12, TNF-alpha, and IL-10. IFN-gamma production was diminished by the addition of anti-IL-12 antibody to the PBMNC cultures. Purified T cells, but not NK cells, produced IFN-gamma effectively when stimulated with L. casei strain Shirota in the presence of monocytes, indicating that monocytes triggered by L. casei strain Shirota help T cells to produce IFN-gamma through secreting IL-12. In addition, NK cell activity and CD69 expression on NK cells increased after cultivation of PBMNC with L. casei strain Shirota. When monocytes were depleted from PBMNC, L. casei strain Shirota did not enhance NK cell activity. These results demonstrate that monocytes play critical roles in the induction of cytokines and following the augmentation of NK cell activity during the stimulation of human PBMNC with L. casei strain Shirota.

Paediatric basis of adult lung disease

Most lung disease throughout life is programmed in utero or early post-natal life. Factors in the fetal environment such as maternal smoking and diet can lead to reduced lung function, immunological modification or symptoms from birth. There are clear genetic components documented for cystic fibrosis, alpha1 anti-trypsin deficiency and asthma. In early life, the outcomes for those predisposed to asthma or allergy appear to be dependent on the relative timing of exposure to infective agents, allergens or helminths. Abnormal airway structure is present in both transient and persistent wheezers. New drugs and environmental manipulations will need to be developed with an understanding of the mechanisms associated with this early programming.

Probiotics and their fermented food products are beneficial for health

Probiotics are usually defined as microbial food supplements with beneficial effects on the consumers. Most probiotics fall into the group of organisms' known as lactic acid-producing bacteria and are normally consumed in the form of yogurt, fermented milks or other fermented foods. Some of the beneficial effect of lactic acid bacteria consumption include: (i) improving intestinal tract health; (ii) enhancing the immune system, synthesizing and enhancing the bioavailability of nutrients; (iii) reducing symptoms of lactose intolerance, decreasing the prevalence of allergy in susceptible individuals; and (iv) reducing risk of certain cancers. The mechanisms by which probiotics exert their effects are largely unknown, but may involve modifying gut pH, antagonizing pathogens through production of antimicrobial compounds, competing for pathogen binding and receptor sites as well as for available nutrients and growth factors, stimulating immunomodulatory cells, and producing lactase. Selection criteria, efficacy, food and supplement sources and safety issues around probiotics are reviewed. Recent scientific investigation has supported the important role of probiotics as a part of a healthy diet for human as well as for animals and may be an avenue to provide a safe, cost effective, and 'natural' approach that adds a barrier against microbial infection. This paper presents a review of probiotics in health maintenance and disease prevention.

Induction of Interleukin-12 by Lactobacillus Strains Having a Rigid Cell Wall Resistant to Intracellular Digestion

Some strains of lactobacilli can stimulate macrophages and dendritic cells to secrete IL-12, which plays a key role in activating innate immunity. We examined the IL-12-inducing ability of 47 Lactobacillus strains belonging to 10 species in mouse peritoneal macrophages, and characterized the properties important for the induction of IL-12. Although considerable differences in IL-12-inducing ability were observed among the strains tested, almost all strains belonging to the Lactobacillus casei group (L. casei, Lactobacillus rhamnosus, and Lactobacillus zeae) or to Lactobacillus fermentum induced high levels of IL-12. Phagocytosis of lactobacilli was necessary for IL-12 induction, and the strains with strong IL-12 induction were relatively resistant to lysis in the macrophages. The sensitivity of Lactobacillus strains to in vitro treatment with M-1 enzyme, a member of the N-acetylmuramidases, was negatively correlated with IL-12-inducing ability. Using a probiotic strain, L. casei strain Shirota (LcS), we showed that the cell wall of LcS could be digested by long-term treatment with a high dose of M-1 enzyme and that the IL-12-inducing ability was diminished according to the duration of the enzyme treatment. The soluble polysaccharide-peptidoglycan complex released from the cell wall of LcS did not induce IL-12, whereas the insoluble intact cell wall of LcS induced IL-12. These results suggest that the intact cell wall structure of lactobacilli is an important element in the ability to induce IL-12 and that Lactobacillus strains having a rigid cell wall resistant to intracellular digestion effectively stimulate macrophages to induce IL-12.

Involvement of innate immunity in the development of inflammatory and autoimmune diseases

Initial events and effector mechanisms of most inflammatory and autoimmune diseases remain largely unknown. Dysfunction of the innate and adaptive immune systems associated with mucosae (the major interface between the organism and its environment, e.g., microbiota, food) can conceivably cause impairment of mucosal barrier function and development of localized or systemic inflammatory and autoimmune processes. Animal models help in elucidating the etiology and pathogenetic mechanisms of human diseases, such as the inflammatory bowel diseases, Crohn's disease and ulcerative colitis, severe chronic diseases affecting the gut. To study the role of innate immunity and gut microbiota in intestinal inflammation, colitis was induced by dextran sulfate sodium (DSS) in mice with severe combined immunodeficiency (SCID). Conventionally reared (microflora-colonized) SCID mice displayed severe inflammation like that seen in immunocompetent Balb/c mice, whereas only minor changes appeared in the intestinal mucosa of DSS-fed gnotobiotic germ-free SCID mice. The presence of microflora facilitates the inflammation in DSS-induced colitis that develops in immunodeficient SCID mice, that is, in the absence of T and B lymphocytes. Celiac disease, a chronic autoimmune small bowel disorder, afflicts genetically susceptible individuals with wheat gluten intolerance. We showed that, in contrast with any other food proteins, wheat gliadin and its peptic fragments activate mouse macrophages and human monocytes to produce proinflammatory cytokines through the nuclear factor-kappaB signaling pathway. Activation of innate immunity cells by food proteins or components from gut microbiota thus could participate in the impairment of intestinal mucosa and the development of intestinal and/or systemic inflammation.

Probiotics as flourishing benefactors for the human body

This article provides a comprehensive review of the beneficial effects of various strains of probiotics in preventing and treating certain diseases. Currently, changed lifestyles as well as the increased use of antibiotics are significant factors challenging the preservation of a healthy intestinal microflora. The concept of probiotics is to restore and uphold a microflora advantageous for the human body. Probiotics are found in a number of fermented dairy products, infant formula, and dietary supplements. In the presence of prebiotics, which are nondigestible food ingredients favorable for probiotic growth, their survival in the intestine is ameliorated.

Probiotics and the immune response

Beneficial effects exerted by probiotic bacteria in the treatment of human disease may be broadly classified as those effects which arise due to activity in the large intestine and are related to colonization or inhibition of pathogen growth; and those effects which arise in both the small and large intestine, and are related to enhancement of the host immune response and intestinal barrier function. In a strain dependent fashion, probiotic bacteria can enhance intestinal barrier function and modulate signal transduction pathways and gene expression in epithelial and immune cells. Oral administration of live probiotics and bacterial structural components can also differentially modulate dendritic cells resulting in an increased production of IL-10 and regulatory T cells. Both innate and adaptive immune responses can be modulated by probiotic bacteria.

Faecal SIgA secretion in infants fed on pre- or probiotic infant formula

Secretory immunoglobulin A (SIgA) plays an important role in the defence of the gastrointestinal tract. The level of faecal SIgA antibody is associated with increased neutralization and clearance of viruses. Formula-fed infants who lack the transfer of protective maternal SIgA from breast milk may benefit from strategies to support maturation of humoral immunity and endogenous production of SIgA. We aimed at studying the effects of standard, prebiotic and probiotic infant formulas on the faecal SIgA levels. At birth, infants of whom the mother had decided not to breastfeed were allocated to one of three formula groups in a randomized, double-blind fashion. Nineteen infants received standard infant formula; 19 received prebiotic formula containing a specific mixture of 0.6 g galacto-oligosaccharides (GOS)/fructo-oligosaccharides (FOS)/100 ml formula and 19 received probiotic formula containing 6.0 x 10(9) cfu Bifidobacterium animalis/100 ml formula. Faecal samples were taken on postnatal day 5, day 10, wk 4 and every 4 wk thereafter until wk 32. SIgA in faeces was determined by an enzyme-linked immunosorbent assay. During the intervention, infants fed on prebiotic formula showed a trend towards higher faecal SIgA levels compared with the standard formula-fed infants reaching statistical significance at the age of 16 wk. In contrast, infants fed on the probiotic formula showed a highly variable faecal SIgA concentration with no statistically significant differences compared with the standard formula group. Formula-fed infants may benefit from infant formulas containing a prebiotic mixture of GOS and FOS because of the observed clear tendency to increase faecal SIgA secretion. Adding viable B. animalis strain Bb-12 to infant formula did not reveal any sign for such a trend.

Probiotics: facts and myths

In recent years there has been a significant upsurge in research on the characterisation and verification of the potential health benefits associated with the use of probiotics. In addition, the market for probiotics continues to expand exponentially as consumers (mostly healthy individuals) rely on health claims made by manufacturers to make their choices. This review appraises the available evidence for and against the health claims associated with probiotics. The use of probiotics in promoting gastrointestinal health and immunity, and their use in the prevention of urogenital infections, allergies and cancer are reviewed. Furthermore, issues surrounding the use of probiotics in healthy individuals, the safety of probiotics and regulatory concerns are addressed. There is scientific evidence that specific strains of probiotic microorganisms confer health benefits on the host and are safe for human use. However, this evidence cannot be extrapolated to other strains, as these effects are strain-specific. Probiotics have potential health benefits for conditions such as gastrointestinal infections, genitourinary infections, allergies and certain bowel disorders, all of which afflict a considerable proportion of the global population. However, considerable work is still needed to confirm these potential health benefits.

Oral tolerance: lessons on treatment of food allergy

Oral tolerance is the active non-response by the immune system to an antigen administered through the oral route. It is postulated that food hypersensitivity results from a breakdown in oral tolerance induction, and the importance of oral tolerance in food hypersensitivity can be traced back to classic experiments from 1911 in which guinea pigs were protected from anaphylaxis by prior feeding of antigen. Host and antigenic factors play a role in determining the pathways and mechanisms to which a fed antigen can gain tolerance. Recent studies have demonstrated the potential of using oral tolerance to treat food allergies, and additional studies are necessary to further our understanding of mechanisms of oral tolerance induction.

Developmentally regulated intestinal expression of IFN-gamma and its target genes and the age-specific response to enteric Salmonella infection

Young infants are highly susceptible to systemic dissemination of enteric pathogens such as Salmonella typhimurium when compared with older individuals. The mechanisms underlying this differential susceptibility have not been defined clearly. To better understand this phenomenon, we examined the responses of adult mice and preweaned pups to oral infection by S. typhimurium. We found clear age-specific differences, namely, an attenuated intestinal inflammatory response and a higher systemic bacterial burden in the pups compared with the adults. To elucidate the molecular basis for these differences, we obtained a microarray-based profile of gene expression in the small intestines of uninfected adult and preweaned animals. The results indicated a striking age-dependent increase in the intestinal expression of a number of IFN-gamma-regulated genes involved in antimicrobial defense. This finding was confirmed by real-time quantitative PCR, which also demonstrated an age-dependent increase in intestinal expression of IFN-gamma. The developmental up-regulation of the IFN-gamma-regulated genes was dependent on both IFN-gamma and a normal commensal microflora, as indicated by experiments in IFN-gamma-knockout mice and germfree mice, respectively. However, the increase in expression of IFN-gamma itself was independent of the commensal flora. The functional importance of IFN-gamma in the immunological maturation of the intestine was confirmed by the observation that the response of adult IFN-gamma-knockout animals to S. typhimurium infection resembled that of the wild-type pups. Our findings thus reveal a novel role for IFN-gamma in the developmental regulation of antimicrobial responses in the intestine.

Mucosal immunity and allergic responses: lack of regulation and/or lack of microbial stimulation?

Allergic hyperreactivity is defined as an exaggerated immune response [typically immunoglobulin E (IgE) but also non-IgE mediated] toward harmless antigenic stimuli. The prevalence of allergic disease has increased dramatically during the last 20 years, especially in developed countries. Both genetic and environmental factors contribute to susceptibility to allergy. Evidence has emerged supporting the hypothesis that a reduction in antigenic stimulation brought about by widespread vaccination, improvements in standards of hygiene, and extensive use of antibiotics has contributed to the dysregulation of T-helper 2 cell (Th2) type responsiveness that typifies allergy. Regulation of the inherently Th2-biased mucosal immune response is crucial both to the maintenance of homeostasis at this strategic defensive barrier and to the prevention of allergic disease. The ability of Th1 responses to counter-regulate Th2 reactivity is well characterized. More recently, interest has centered on regulatory T cells, which can suppress both Th1 and Th2 cells through the secretion of immunosuppressive cytokines such as interleukin-10 and transforming growth factor-beta. In this review, we discuss the basic cellular mechanisms of allergic diseases at mucosal surfaces, focusing on allergic responses to food, before examining newer work that suggests the induction of allergic hyperreactivity is due to a deficient immunoregulatory network, a lack of microbial stimulation, or both.