Early age exposure to moisture damage and systemic inflammation at the age of 6 years.

Cross-sectional studies have shown that exposure to indoor moisture damage and mold may be associated with subclinical inflammation. Our aim was to determine whether early age exposure to moisture damage or mold is prospectively associated with subclinical systemic inflammation or with immune responsiveness in later childhood. Home inspections were performed in children's homes in the first year of life. At age 6 years, subclinical systemic inflammation was measured by serum C-reactive protein (CRP) and blood leukocytes and immune responsiveness by ex vivo production of interleukin 1-beta (IL-1ß), IL-6, and tumor necrosis factor alpha (TNF-α) in whole blood cultures without stimulation or after 24 hours stimulation with phorbol 12-myristate 13-acetate and ionomycin (PI), lipopolysaccharide (LPS), or peptidoglycan (PPG) in 251-270 children. Moisture damage in child's main living areas in infancy was not significantly associated with elevated levels of CRP or leukocytes at 6 years. In contrast, there was some suggestion for an effect on immune responsiveness, as moisture damage with visible mold was positively associated with LPS-stimulated production of TNF-α and minor moisture damage was inversely associated with PI-stimulated IL-1ß. While early life exposure to mold damage may have some influence on later immune responsiveness, it does not seem to increase subclinical systemic inflammation in later life.

Synergistic proinflammatory interactions of microbial toxins and structural components characteristic to moisture-damaged buildings.

Indoor exposure to microbes and their structural and metabolic compounds is notoriously complex. To study proinflammatory interactions between the multiple microbial agents, macrophages derived from human THP-1 monocytic cells were exposed to several concentrations of microbial toxins alone (emodin, enniatin B, physcion, sterigmatocystin, valinomycin) and in combination with microbial structural components (bacterial lipopolysaccharide [LPS] or fungal ß-glucan). While the expression of proinflammatory cytokines TNFα and IL-1ß to single toxins alone was modest, low-dose co-exposure with structural components increased the responses of emodin, enniatin B, and valinomycin synergistically, both at the mRNA and protein level, as measured by RT-qPCR and ELISA, respectively. Co-exposure of toxins and ß-glucan resulted in consistent synergistically increased expression of several inflammation-related genes, while some of the responses with LPS were also inhibitory. Co-exposure of toxins with either ß-glucan or LPS induced also mitochondrial damage and autophagocytosis. The results demonstrate that microbial toxins together with bacterial and fungal structural components characteristic to moisture-damaged buildings can have drastic synergistic proinflammatory interactions at low exposure levels.

Microbial secondary metabolites in homes in association with moisture damage and asthma.

We aimed to characterize the presence of microbial secondary metabolites in homes and their association with moisture damage, mold, and asthma development. Living room floor dust was analyzed by LC-MS/MS for 333 secondary metabolites from 93 homes of 1-year-old children. Moisture damage was present in 15 living rooms. At 6 years, 8 children had active and 15 lifetime doctor-diagnosed asthma. The median number of different metabolites per house was 17 (range 8-29) and median sum load 65 (4-865) ng/m(2) . Overall 42 different metabolites were detected. The number of metabolites present tended to be higher in homes with mold odor or moisture damage. The higher sum loads and number of metabolites with loads over 10 ng/m(2) were associated with lower prevalence of active asthma at 6 years (aOR 0.06 (95% CI <0.001-0.96) and 0.05 (<0.001-0.56), respectively). None of the individual metabolites, which presence tended (P < 0.2) to be increased by moisture damage or mold, were associated with increased risk of asthma. Microbial secondary metabolites are ubiquitously present in home floor dust. Moisture damage and mold tend to increase their numbers and amount. There was no evidence indicating that the secondary metabolites determined would explain the association between moisture damage, mold, and the development of asthma.

Moisture damage in home associates with systemic inflammation in children.

This study investigated the association between confirmed moisture damage in homes and systemic subclinical inflammation in children. Home inspections were performed in homes of 291 children at the age of 6 years. Subclinical inflammation at the age of 6 years was assessed by measuring the circulating levels of C-reactive protein (CRP) and leukocytes in peripheral blood and fractional exhaled nitric oxide (FeNO). Proinflammatory cytokines interleukin (IL)-1ß and IL-6 and tumor necrosis factor (TNF)-α were measured in unstimulated, and in phorbol 12-myristate 13-acetate and ionomycin (PI), lipopolysaccharide (LPS), or peptidoglycan (PPG)-stimulated whole blood. Major moisture damage in the child's main living areas (living room, kitchen, or child's bedroom) and moisture damage with mold in the bathroom were associated with increased levels of CRP and stimulated production of several proinflammatory cytokines. There were no significant associations between moisture damage/visible mold and leukocyte or FeNO values. The results suggest that moisture damage or mold in home may be associated with increased systemic subclinical inflammation and proinflammatory cytokine responsiveness.

Anti-inflammatory effects of probiotic yogurt in inflammatory bowel disease patients.

Our aim was to assess anti-inflammatory effects on the peripheral blood of subjects with inflammatory bowel disease (IBD) who consumed probiotic yogurt for 1 month. We studied 20 healthy controls and 20 subjects with IBD, 15 of whom had Crohn's disease and five with ulcerative colitis. All the subjects consumed Lactobacillus rhamnosus GR-1 and L. reuteri RC-14 supplemented yogurt for 30 days. The presence of putative regulatory T (T(reg)) cells (CD4(+) CD25(high)) and cytokines in T cells, monocytes and dendritic cells (DC) was determined by flow cytometry from peripheral blood before and after treatment, with or without ex vivo stimulation. Serum and faecal cytokine concentrations were determined by enzyme-linked immunosorbent assays. The proportion of CD4(+) CD25(high) T cells increased significantly (P = 0.007) in IBD patients, mean (95% confidence interval: CI) 0.84% (95% CI 0.55-1.12) before and 1.25% (95% CI 0.97-1.54) after treatment, but non-significantly in controls. The basal proportion of tumour necrosis factor (TNF)-alpha(+)/interleukin (IL)-12(+) monocytes and myeloid DC decreased in both subject groups, but of stimulated cells only in IBD patients. Also serum IL-12 concentrations and proportions of IL-2(+) and CD69(+) T cells from stimulated cells decreased in IBD patients. The increase in CD4(+) CD25(high) T cells correlated with the decrease in the percentage of TNF-alpha- or IL-12-producing monocytes and DC. The effect of the probiotic yogurt was confirmed by a follow-up study in which subjects consumed the yogurt without the probiotic organisms. Probiotic yogurt intake was associated with significant anti-inflammatory effects that paralleled the expansion of peripheral pool of putative T(reg) cells in IBD patients and with few effects in controls.

Aberrant composition of gut microbiota of allergic infants: a target of bifidobacterial therapy at weaning?

BACKGROUND: Recent data have outlined a relationship between the composition of the intestinal microflora and allergic inflammation, and demonstrated the competence of probiotics in downregulation of such inflammation. AIMS: Our aims were to characterise the relationship between gut microbes and the extent of allergic sensitisation and to assess whether the efficacy of bifidobacterial supplementation in the treatment of allergy could relate to modulation of the intestinal microbiota. METHODS: This randomised study included 21 infants with early onset atopic eczema of whom eight were intolerant (highly sensitised group (HSG)) and 13 tolerant (sensitised group (SG)) to extensively hydrolysed whey formula (EHF). In the SG, six were weaned to EHF without (placebo group (PG)) and seven to EHF with Bifidobacterium lactis Bb-12 supplementation (bifidobacteria treated group (BbG)). The faecal microflora of infants in the HSG was analysed only before weaning whereas in the SG the faecal microflora was analysed both before and after weaning. RESULTS: Infants in the HSG had greater numbers of lactobacilli/enterococci than those in the SG. Serum total IgE concentration correlated directly with Escherichia coli counts in all infants and with bacteroides counts in the HSG, indicating that the presence of these bacteria is associated with the extent of atopic sensitisation. The effect of supplementation was characterised as a decrease in the numbers of Escherichia coli and protection against an increase in bacteroides numbers during weaning. CONCLUSIONS: These data indicate that bifidobacterial supplementation appears to modify the gut microbiota in a manner that may alleviate allergic inflammation. Further studies are needed to confirm this conclusion.

Probiotics: a role in the treatment of intestinal infection and inflammation?

Probiotic therapy is based on the concept of normal healthy microflora. The development of novel means of characterising the gut microflora, in particular those based on the different levels of conservation in the ribosomal RNA sequences of different genera, have opened up new angles on the role of the gut microflora in health and disease. Components of the human intestinal microflora or organisms entering the intestine may have harmful or beneficial effects on human health. Abundant evidence implies that specific strains selected from the healthy gut microflora exhibit powerful antipathogenic and anti-inflammatory capabilities, and are consequently involved with enhanced colonisation resistance in the intestine. Realisation of this has led to the introduction of novel modes of therapeutic and prophylactic intervention based on the consumption of mono and mixed cultures of beneficial live microorganisms as probiotics.

Characterizing the composition of intestinal microflora as a prospective treatment target in infant allergic disease.

We assessed the fecal microflora of 10 healthy infants and 27 infants with atopic eczema during breast-feeding and after weaning. The atopic infants had less frequently Gram-positive species among the most predominant aerobes and smaller total cell counts. Further differences were associated with more extensive manifestations, seen as higher bacteroides and lower bifidobacteria counts. Weaning resulted in decreased bacteroides counts in atopic and total cell counts in healthy infants and diminished predominance by bifidobacteria in both. In conclusion, the most prominent question raised by these data is whether Gram-positive bacteria may have distinctive importance in protection against atopic sensitization. Further studies aiming to answer this question are warranted.

Good adhesion properties of probiotics: a potential risk for bacteremia?

The ability to adhere to human intestinal mucus was tested for lactic acid bacteria of clinical blood culture, human fecal and dairy origin. The blood culture isolates were found to adhere better than the dairy strains. Of the Lactobacillus rhamnosus strains (nine clinical, 10 fecal and three dairy), blood culture isolates adhered better than the fecal strains. Although these results indicate a trend for blood culture isolates to bind to intestinal mucus in higher numbers than strains of dairy and human fecal origin, other factors are also likely to be involved in the etiology of lactobacillemia since some of the clinical Lactobacillus isolates exhibited a relatively low level of adhesion.

Differences in the gut bacterial flora of healthy and milk-hypersensitive adults, as measured by fluorescence in situ hybridization.

We enumerated the predominant gut genera from fecal samples of nine healthy and eight milk-hypersensitive adults both before and after 4 weeks Lactobacillus rhamnosus GG (LGG) supplementation. The anaerobic intestinal microflora of milk-hypersensitive adults was found to resemble that of healthy adults. LGG-consumption resulted in a significant increase in the number of bifidobacteria in healthy but not in milk-hypersensitive subjects, as well as a general increase in bacterial numbers in all other bacterial genera tested in both groups. In conclusion, the composition of the gut microbiota in milk-hypersensitive adults appears to be normal. LGG may have potential in reinforcing the endogenous flora.

Adherence of probiotic bacteria to human intestinal mucus in healthy infants and during rotavirus infection.

The concentration of fecal mucin and the adhesion of specific probiotics and their combinations in the intestinal mucus of infants during and after rotavirus diarrhea and in healthy children were determined. Mucus was prepared from fecal samples from 20 infants during and after rotavirus diarrhea and from 10 healthy age-matched children. Mucin concentration was determined, and the adhesion of five probiotics-Lactobacillus rhamnosus GG, Lactobacillus casei Shirota, Lactobacillus paracasei F19, Lactobacillus acidophilus LA5, and Bifidobacterium lactis Bb12-and their combinations was tested in vitro. The mean concentrations of fecal mucin during and after rotavirus diarrhea, 15.2 and 14.1 mg/g, were comparable to that in healthy children, 14.9 mg/g. The adherence of probiotics ranged from 1 to 34% in healthy subjects as indicated for the following strains: L. rhamnosus GG, 34%; B. lactis Bb12, 31%; L. acidophilus LA5, 4%; L. paracasei F19, 3%; and L. casei Shirota, 1% (P = 0.0001). The distinctive pattern of probiotic adherence was not influenced by rotavirus diarrhea. The adhesion of Bb12 in the presence of GG increased from 31 to 39% in healthy infants (P = 0.018) and in episodes of diarrhea increased from 26 to 44% (P = 0.001). Rotavirus diarrhea does not decrease the production of fecal mucin or with respect to the adhesion of probiotic bacteria tested in vitro. Combination of specific probiotic strains may enhance adherence in a synergistic manner. Optimal clinical application of these interactions may offer novel therapeutic guidelines for the treatment and prevention of gastrointestinal infections.

Distinct patterns of neonatal gut microflora in infants in whom atopy was and was not developing.

BACKGROUND: Improved hygiene has altered early microbial exposure by reducing childhood infections, which has been suggested as a cause for the continuously rising prevalence of atopic diseases. On the basis of both intensity and timing of stimulus, it has been hypothesized that exposure to commensal microflora may represent another key protective modulator of immunity against atopy and subsequent atopic diseases. OBJECTIVE: We sought to investigate whether differences in early gut microflora precede the later development of atopic sensitization. METHODS: Intestinal microflora from 76 infants at high risk of atopic diseases were analyzed at 3 weeks and 3 months of age by using conventional bacterial cultivation and 2 culture-independent methods, gas-liquid chromatography of bacterial cellular fatty acids and quantitative fluorescence in situ hybridization of bacterial cells. Infants evincing at least one positive skin prick reaction at 12 months were grouped as atopic subjects, and those without positive reactions were grouped as nonatopic subjects. RESULTS: Atopic sensitization was observed in 22 (29%) of 76 children. At 3 weeks, the bacterial cellular fatty acid profile in fecal samples differed significantly between infants in whom atopy was and was not developing (P =.005). By using fluorescence in situ hydridization, atopic subjects had more clostridia (geometric mean [95% confidence interval]: 9.3 x 10(7) [3.8-22.9 x 10(7)] vs 3.3 x 10(7) [1.8-6.1 x 10(7)], P =.04) and tended to have fewer bifidobacteria (1.8 x 10(9) [0.4-7.6 x 10(9)] vs 6.1 x 10(9) [2.5-14.6 x 10(9)], P =.11) in their stools than nonatopic subjects, resulting in a reduced ratio of bifidobacteria to clostridia (P =.03). The differences were not detected by bacterial cultivation. CONCLUSION: Differences in the neonatal gut microflora precede the development of atopy, suggesting a crucial role of the balance of indigenous intestinal bacteria for the maturation of human immunity to a nonatopic mode.

The mucus binding of Bifidobacterium lactis Bb12 is enhanced in the presence of Lactobacillus GG and Lact. delbrueckii subsp. bulgaricus.

The ability to adhere to mucosal surfaces is related to many probiotic health effects. In the presence of Lactobacillus GG or Lact. bulgaricus, the adhesion of Bifidobacterium lactis Bb12 to a mucus model was more than doubled. Other tested lactobacilli did not affect the adhesion, nor was the adhesion of the lactobacilli influenced by the bifidobacteria. Co-aggregation between Bif. lactis Bb12 and the tested lactobacilli was insignificant and does not explain the observed effect. The results suggest that combinations of probiotics strains may have synergistic adhesion effects. Such specific strain combinations should also be assessed in clinical studies.

Effects of orally administered viable Lactobacillus rhamnosus GG and Propionibacterium freudenreichii subsp. shermanii JS on mouse lymphocyte proliferation.

Immunomodulation by probiotics is a subject of growing interest, but the knowledge of dose response and time profile relationships is minimal. In this study we examined the effects of Lactobacillus rhamnosus GG (LGG) and Propionibacterium freudenreichii subsp. shermanii JS (PJS) on the proliferative activity of murine lymphocytes ex vivo. Dose dependency was assessed by treating animals perorally with a low or a high dose (i.e., 10(9) or 10(12) viable bacteria/kg of body weight) for 7 days. The lower dose levels of each strain appeared to enhance T-cell proliferation at the optimal concanavalin A (ConA) concentration (by 69 to 84%) and B-cell proliferation at the optimal and supraoptimal concentrations of lipopolysaccharide (by 57 to 82%). B-cell proliferation was also enhanced by the high LGG dose (by 32 to 39%) but was accompanied by a marginal decrease in T-cell proliferation (by 8%) at the optimal ConA concentration. The time profiles of the immune responses were assessed after daily treatment with the higher dose for 3, 7, and 14 days. A significant decrease in basal lymphoproliferation (by 32 to 42%) was observed with PJS treatment after the 3- and 7-day periods; however, this activity returned to control levels after 14 days of treatment, which also resulted in significantly enhanced T-cell proliferation at optimal and supraoptimal ConA concentrations (by 24 to 80%). The 14-day LGG treatment also enhanced the latter activity (by 119%). In conclusion, LGG and PJS have specific dose- and duration-dependent immunomodulatory effects on the proliferative activity of B and T lymphocytes and may also reduce lymphocyte sensitivity to the cytotoxic effects of lectin mitogens.

The effect of orally administered viable probiotic and dairy lactobacilli on mouse lymphocyte proliferation.

Four common Lactobacillus strains were screened for their effects on proliferation of mouse splenic lymphocytes. Mice received perorally 10(9) viable bacteria kg(-1) body weight for 7 days. Lactobacillus acidophilus treatment enhanced ex vivo basal proliferation (by 43%) and B-cell response at suboptimal and optimal concentrations of lipopolysaccharide (LPS) (by 27-28%). Conversely, Lactobacillus casei, Lactobacillus gasseri and Lactobacillus rhamnosus inhibited both basal proliferation (by 14-51%) and mitogen-stimulated lymphoproliferation, particularly at supra-optimal concentrations of concanavalin A (by 43-68%) and LPS (by 23-62%). Therefore, these Lactobacillus strains demonstrate strain-specific effects on B- and T-cells and may also alter the splenocyte sensitivity to the cytotoxic effects of mitogens.

Healthy gut microflora and allergy: factors influencing development of the microbiota.

In humans, microbial colonization of the intestine begins just after birth. However, development of the normal flora is a gradual process, which is initially determined by factors such as composition of the maternal gut microflora, environment and possibly also by genetic aspects. A number of variables, such as the degree of hygiene, mode of delivery, use of antibiotics or other medication and a need for nursing in incubators, can all have a substantial effect on microbial colonization and development. Current knowledge on the significance and impact of such alterations on the health of the infant is poor. However, the essential role of the gut microflora in the development of the gut immune system indicates that a close relationship between allergic sensitization and the development of the intestinal microflora may occur in infancy. Intestinal micro-organisms could down-regulate the allergic inflammation by counterbalancing type 2 T-helper cell responses and by enhancing antigen exclusion through an immunoglobulin (Ig)A response. The efficacy of probiotics (microbial food additions) in the management of food allergy has been demonstrated, and these data suggest that also prebiotics, food components that target certain indigenous gut bacteria, can possibly be used for this purpose. In conclusion, the developmental pattern of the normal gut microbiota in allergic infants poses an important research avenue, as the role of the gut microflora in the mechanisms of allergy, and thereby the possible targets for efficient bacteriotherapy, are currently undetermined.

In vitro adhesion and platelet aggregation properties of bacteremia-associated lactobacilli.

Eight bacteremia-associated Lactobacillus strains were evaluated in vitro for the ability to adhere to human intestinal mucosa and to aggregate platelets. Adherence varied significantly among the strains, and platelet aggregation was induced by three strains. In conclusion, strong binding ability does not appear to be a prerequisite for the involvement of lactobacilli in bacteremia or to their ability to aggregate platelets.