Intestinal mucosal adherence and translocation of commensal bacteria at the early onset of type 2 diabetes: molecular mechanisms and probiotic treatment

A fat-enriched diet modifies intestinal microbiota and initiates a low-grade inflammation, insulin resistance and type-2 diabetes. Here, we demonstrate that before the onset of diabetes, after only one week of a high-fat diet (HFD), live commensal intestinal bacteria are present in large numbers in the adipose tissue and the blood where they can induce inflammation. This translocation is prevented in mice lacking the microbial pattern recognition receptors Nod1 or CD14, but overtly increased in Myd88 knockout and ob/ob mouse. This ‘metabolic bacteremia’ is characterized by an increased co-localization with dendritic cells from the intestinal lamina propria and by an augmented intestinal mucosal adherence of non-pathogenic Escherichia coli. The bacterial translocation process from intestine towards tissue can be reversed by six weeks of treatment with the probiotic strain Bifidobacterium animalis subsp. lactis 420, which improves the animals' overall inflammatory and metabolic status. Altogether, these data demonstrate that the early onset of HFD-induced hyperglycemia is characterized by an increased bacterial translocation from intestine towards tissues, fuelling a continuous metabolic bacteremia, which could represent new therapeutic targets

Pötsimikrobitoimintaa tehostavan erikoisrehun vaikutus lypsylehmien rehunsyöntikykyyn, tuotokseen ja immuunistatukseen

Maidon erityksen alkaessa lypsylehmän energian ja ravintoaineiden tarve lisääntyy nopeasti ja lehmä alkaa mobilisoida kudoksistaan rasva­ ja aminohappoja. Voimakas kudosmobilisaatio lisää aineen­vaihduntasairauksien riskiä. Poikimisen läheisyydessä myös lypsylehmän immuunijärjestelmän toi­minta on tilapäisesti heikentynyt.Tutkimuksen tarkoituksena oli selvittää hiivavalmistetta sisältävän erikoisrehun vaikutusta lyp­sylehmien rehunsyöntikykyyn, tuotokseen ja immuunistatukseen. Kokeessa oli mukana 12 ensim­mäistä kertaa poikivaa ja 12 useammin kuin kaksi kertaa poikinutta lehmää. Koe alkoi kaksi viikkoa ennen poikimista ja kesti 8 viikkoa poikimisen jälkeen. Ennen poikimista lehmät saivat 1,5 kg/d täysväkirehua ja 1,5 kg/d energiatäydennysrehua sekä säilörehua lasketun tarpeen mukaan. Koeryhmän energiatäydennysrehu (koerehu) sisälsi 1,33 % hiivavalmistetta (Progut, Suomen Rehu Oy). Poikimisen jälkeen vanhempien lehmien väkirehumäärä nostettiin 15 kiloon ja ensikoiden 12 kiloon. Väkirehuannoksessa oli edelleen 1,5 kg energiatäydennysrehua tai koerehua. Säilörehua annettiin vapaasti.Rehujen syönnissä, maitotuotoksessa tai maidon pitoisuuksissa ei ollut tilastollisesti merkitseviä ryhmien välisiä eroja poikimisen jälkeen. Ensikoiden keskimääräinen maitotuotos oli 29,1 kg/d ja vanhempien lehmien 46,9 kg/d. Ruokinnan ja poikimakerran välillä ei ollut merkitseviä yhdysvaikutuksia. Koeryhmän vanhempien lehmien maidon rasvapitoisuus (45,3 vs. 42,3 g/kg, P=0,32) oli kuitenkin numeroarvollisesti suurempi kuin kontrolliryhmän, jolloin vastaavasti myös energiakorjatussa maitotuotoksessa (EKM) oli 5,3 % ero (49,3 vs. 46,8 kg/d, P=0,20).Elopainon  tai  kuntoluokan  muutoksissa  poikimisen  jälkeen  ei  ollut  ryhmien  välisiä  eroja. Koeryhmän vanhempien lehmien plasman NEFA­-pitoisuus oli korkeampi kuin kontrolliryhmän (0,52 vs. 0,37 mmol/l, P=0,08). Ensikoilla vastaavaa eroa ei ollut. Veren asetoasetaatti­ ja ureapitoisuuksissa tai valkuaisen hyväksikäytössä maidontuotantoon ei ollut ryhmien välisiä eroja. Kontrolli­ ja koeryhmän seerumin IgA­-pitoisuuksien välillä ei havaittu eroa. Useamman kerran poikineiden lehmien seerumin IgA-­pitoisuudet olivat korkeampia kuin ensikoiden. Toisaalta vanhempien lehmien seerumin IgA­-pitoisuus sekä laski jyrkemmin poikimisen jälkeen että alkoi palautua nopeammin verrattuna ensikoihin.Johtopäätöksenä voidaan todeta, että koerehulla ei ollut tilastollisesti merkitsevää vaikutusta en­sikoiden tai vanhempien lehmien rehun syöntiin tai maitotuotokseen. Veren vapaiden rasvahappojen pitoisuus oli kuitenkin suurempi koerehua saaneiden vanhempien lehmien ryhmässä kuin kontrolliryhmässä, mikä pyrki nostamaan maidon rasvapitoisuutta ja EKM­-tuotosta koeryhmässä. Vastaavasti koeryhmän vanhempien lehmien EKM­-tuotos syötyä kuiva­ainekiloa kohti oli parempi kuin kontrolliryhmän. Vanhempien lehmien seerumin keskimääräinen IgA­-pitoisuus oli korkeampi kuin ensikoiden, mutta koe­ ja kontrolliryhmän seerumin IgA-­pitoisuuksissa ei ollut eroa

In Vitro Adhesion Specificity of Indigenous Lactobacilli within the Avian Intestinal Tract

In vitro adherence of Lactobacillus strains to cell and tissue types along the chicken alimentary tract and to ileal mucus were determined. Fresh isolates from chickens adhered to the epithelium of crop and, in a strain-dependent manner, to follicle-associated epithelium and the apical surfaces of mature enterocytes of intestinal villi. No adherence to the apical surfaces of undifferentiated enterocytes, the mucus-producing goblet cells, or the ileal mucus was detected

Specific probiotics alleviate allergic rhinitis during the birch pollen season

AIM: To investigate whether birch pollen allergy symptoms are linked with gut microbiota changes and whether probiotics have an effect on these. METHODS: Forty seven children with confirmed birch pollen allergy were randomized to receive either a probiotic combination of Lactobacillus acidophilus (L. acidophilus) NCFM(TM) (ATCC 700396) and Bifidobacterium lactis (B. lactis) Bl-04 (ATCC SD5219) or placebo in a double-blind manner for 4 mo, starting prior to onset of the birch pollen season. Symptoms were recorded in a diary. Blood samples were taken for analysis of cytokines and eosinophils. Fecal samples were analysed for microbiota components, calprotectin and IgA. Nasal swabs were taken for analysis of eosinophils. RESULTS: The pollen season induced a reduction in Bifidobacterium, Clostridium and Bacteroides which could not be prevented by the probiotic intervention. During the intervention, significantly higher numbers of B. lactis 11.2 × 10(7) ± 4.2 × 10(7) vs 0.1 × 10(7) ± 0.1 × 10(7) bacteria/g feces (P < 0.0001) and L. acidophilus NCFM(TM) 3.5 × 10(6) ± 1.3 × 10(6) vs 0.2 × 10(6) ± 0.1 × 10(6) bacteria/g feces (P < 0.0001) were observed in the probiotic group compared to the placebo group. During May, there was a tendency for fewer subjects, (76.2% vs 95.2%, P = 0.078) to report runny nose, while during June, fewer subjects, 11.1% vs 33.3%, reported nasal blocking in the probiotics group (P = 0.101). Concomitantly, fewer subjects in the probiotic group had infiltration of eosinophils in the nasal mucosa compared to the placebo group, 57.1% vs 95% (P = 0.013). Eye symptoms tended to be slightly more frequent in the probiotic group, 12.5 d [interquartile range (IQR) 6-18] vs 7.5 d (IQR 0-11.5) (P = 0.066) during May. Fecal IgA was increased in the placebo group during the pollen season; this increase was prevented by the probiotics (P = 0.028). CONCLUSION: Birch pollen allergy was shown to be associated with changes in fecal microbiota composition. The specific combination of probiotics used was shown to prevent the pollen-induced infiltration of eosinophils into the nasal mucosa, and indicated a trend for reduced nasal symptoms

Polydextrose, Lactitol, and Fructo-Oligosaccharide Fermentation by Colonic Bacteria in a Three-Stage Continuous Culture System

In vitro fermentations were carried out by using a model of the human colon to simulate microbial activities of lower gut bacteria. Bacterial populations (and their metabolic products) were evaluated under the effects of various fermentable substrates. Carbohydrates tested were polydextrose, lactitol, and fructo-oligosaccharide (FOS). Bacterial groups of interest were evaluated by fluorescence in situ hybridization as well as by species-specific PCR to determine bifidobacterial species and percent-G+C profiling of the bacterial communities present. Short-chain fatty acids (SCFA) produced during the fermentations were also evaluated. Polydextrose had a stimulatory effect upon colonic bifidobacteria at concentrations of 1 and 2% (using a single and pooled human fecal inoculum, respectively). The bifidogenic effect was sustained throughout all three vessels of the in vitro system (P = 0.01 seen in vessel 3), as corroborated by the bacterial community profile revealed by %G+C analysis. This substrate supported a wide variety of bifidobacteria and was the only substrate where Bifidobacterium infantis was detected. The fermentation of lactitol had a deleterious effect on both bifidobacterial and bacteroides populations (P = 0.01) and decreased total cell numbers. SCFA production was stimulated, however, particularly butyrate (beneficial for host colonocytes). FOS also had a stimulatory effect upon bifidobacterial and lactobacilli populations that used a single inoculum (P = 0.01 for all vessels) as well as a bifidogenic effect in vessels 2 and 3 (P = 0.01) when a pooled inoculum was used. A decrease in bifidobacteria throughout the model was reflected in the percent-G+C profiles

Culture-Independent Microbial Community Analysis Reveals that Inulin in the Diet Primarily Affects Previously Unknown Bacteria in the Mouse Cecum

Inulin is a well-known fructose-based prebiotic which has been shown to stimulate the growth of bifidobacteria, a bacterial group generally considered beneficial for intestinal health. In the present study, we analyzed inulin-associated shifts in the total bacterial community of wild-type mice and mice carrying a genetically inactivated adenomatous polyposis coli tumor suppressor gene by using DNA-based approaches independent of bacterial culturability. Mice were fed a high-fat, nonfiber diet with or without inulin inclusion at a 10% (wt/wt) concentration. Cecal contents were analyzed after 0, 3, and 9 weeks on the experimental diets. Inulin inclusion significantly affected the total bacterial community structure of the cecum as determined by both a nonselective percent-guanine-plus-cytosine-based profiling analysis and a more specific 16S ribosomal DNA sequence analysis. The shifts included stimulation of bifidobacteria and suppression of clostridia, but sequence comparison revealed that the major shifts were within previously unknown bacterial taxa. Concomitantly, significantly higher bacterial densities, determined by flow cytometry, were observed with the inulin-amended diet, and the metabolism of the cecal bacterial community was altered, as indicated by higher levels of residual short-chain fatty acids, particularly lactic acid. With regard to all of the microbiological parameters measured, the wild-type mice and mice carrying a genetically inactivated adenomatous polyposis coli tumor suppressor gene were essentially identical. Studies of the implications of pre- and probiotics may need to be expanded to include careful analysis of their effects on the entire microbial community, rather than just a few well-known species. Further studies are needed to increase our understanding of the possible roles of currently unknown gastrointestinal bacteria in health and disease