Composition of cecal bile acids in ex‐germfree mice inoculated with human intestinal bacteria

Narushima, Seiko; Iton, Kikuji; Kuruma, Kazuo; Uchida, Keiji

doi:10.1007/s11745-000-0568-0

Cited by 18 publications

(17 citation statements)

References 33 publications

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“…Clostridium cluster IV and Bacteroides also play an important role in the hydrolysis and fermentation of endogenous mucins and probably dietary protein, as well as in the conversion of bile acids and the production of toxins [34,35] . In a cross-sectional study of different European populations, Mueller et al [36] detected the highest levels of the Clostridium cluster IV in the Swedish study population, whose dietary habits were characterized by a high consumption of fish and meat.…”

Section: Discussionmentioning

confidence: 99%

Characterization of Bacteria, Clostridia and<i> Bacteroides</i> in Faeces of Vegetarians Using qPCR and PCR-DGGE Fingerprinting

et al. 2009

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Background/Aims: This study aimed to investigate the quantitative and qualitative changes of bacteria, Bacteroides, Bifidobacterium and Clostridium cluster IV in faecal microbiota associated with a vegetarian diet. Methods: Bacterial abundances were measured in faecal samples of 15 vegetarians and 14 omnivores using quantitative PCR. Diversity was assessed with PCR-DGGE fingerprinting, principal component analysis (PCA) and Shannon diversity index. Results: Vegetarians had a 12% higher abundance of bacterial DNA than omnivores, a tendency for less Clostridium cluster IV (31.86 ± 17.00%; 36.64 ± 14.22%) and higher abundance of Bacteroides (23.93 ± 10.35%; 21.26 ± 8.05%), which were not significant due to high interindividual variations. PCA suggested a grouping of bacteria and members of Clostridium cluster IV. Two bands appeared significantly more frequently in omnivores than in vegetarians (p < 0.005 and p < 0.022). One was identified as Faecalibacterium sp. and the other was 97.9% similar to the uncultured gut bacteriumDQ793301. Conclusions: A vegetarian diet affects the intestinal microbiota, especially by decreasing the amount and changing the diversity of Clostridium cluster IV. It remains to be determined how these shifts might affect the host metabolism and disease risks.

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Section: Discussionmentioning

confidence: 99%

Characterization of Bacteria, Clostridia and<i> Bacteroides</i> in Faeces of Vegetarians Using qPCR and PCR-DGGE Fingerprinting

et al. 2009

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“…However, the percentage of DCA in these mice was the same as that in the other groups. These results indicate that the dominant anaerobic bacterial combination is efficient for the deconjugation of primary bile acids, and that clostridia in human feces may play an important role in the 7α-dehydroxylation of unconjugated primary bile acids in the intestine (31). However, the attempt to establish gnotobiotic (GB) mice whose intestinal bile acids consisted of a certain amount of secondary bile acid with predominant bacteria isolated from limited human flora mice was not successful, indicating that bile acid-transforming bacteria are not necessarily the predominant population in the intestine.…”

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confidence: 81%

Deoxycholic acid formation in gnotobiotic mice associated with human intestinal bacteria

Narushima

Itoh

Miyamoto

et al. 2006

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In humans and animals, intestinal flora is indispensable for bile acid transformation. The goal of our study was to establish gnotobiotic mice with intestinal bacteria of human origin in order to examine the role of intestinal bacteria in the transformation of bile acids in vivo using the technique of gnotobiology. Eight strains of bile acid-deconjugating bacteria were isolated from ex-germ-free mice inoculated with a human fecal dilution of 10(-6), and five strains of 7alpha-dehydroxylating bacteria were isolated from the intestine of limited human flora mice inoculated only with clostridia. The results of biochemical tests and 16S rDNA sequence analysis showed that seven out of eight bile acid-deconjugating strains belong to a bacteroides cluster (Bacteroides vulgatus, B. distasonis, and B. uniformis), and one strain had high similarity with Bilophila wadsworthia. All five strains that converted cholic acid to deoxycholic acid had greatest similarity with Clostridium hylemonae. A combination of 10 isolated strains converted taurocholic acid into deoxycholic acid both in vitro and in the mouse intestine. These results indicate that the predominant bacteria, mainly Bacteroides, in human feces comprise one of the main bacterial groups for the deconjugation of bile acids, and clostridia may play an important role in 7aplha-dehydroxylation of free-form primary bile acids in the intestine although these strains are not predominant. The gnotobiotic mouse with bacteria of human origin could be a useful model in studies of bile acid metabolism by human intestinal bacteria in vivo.

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“…Intestinal bacteria contain enzymes that metabolize BAs and change the BA composition in the intestinal content and thus also in the circulation of the host (Narushima et al, 2000(Narushima et al, , 2006. The capacity of intestinal microbiota to metabolize BAs not only provides intestinal bacteria cellular carbon, nitrogen, and sulfur, but also enables them to be bile resistant and grow in the presence of BAs.…”

Section: Introductionmentioning

confidence: 99%

Importance of Large Intestine in Regulating Bile Acids and Glucagon-Like Peptide-1 in Germ-Free Mice

et al. 2015

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It is known that 1) elevated serum bile acids (BAs) are associated with decreased body weight, 2) elevated glucagon-like peptide-1 (GLP-1) levels can decrease body weight, and 3) germ-free (GF) mice are resistant to diet-induced obesity. The purpose of this study was to test the hypothesis that a lack of intestinal microbiota results in more BAs in the body, resulting in increased BA-mediated transmembrane G protein-coupled receptor 5 (TGR5) signaling and increased serum GLP-1 as a mechanism of resistance of GF mice to diet-induced obesity. GF mice had 2-to 4-fold increased total BAs in the serum, liver, bile, and ileum. Fecal excretion of BAs was 63% less in GF mice. GF mice had decreased secondary BAs and increased taurine-conjugated BAs, as anticipated. Surprisingly, there was an increase in non-12a-OH BAs, namely, b-muricholic acid, ursodeoxycholic acid (UDCA), and their taurine conjugates, in GF mice. Further, in vitro experiments confirmed that UDCA is a primary BA in mice. There were minimal changes in the mRNA of farnesoid X receptor target genes in the ileum (Fibroblast growth factor 15, small heterodimer protein, and ileal bile acid-binding protein), in the liver (small heterodimer protein, liver receptor homolog-1, and cytochrome P450 7a1), and BA transporters (apical sodium dependent bile acid transporter, organic solute transporter a, and organic solute transporter b) in the ileum of GF mice. Surprisingly, there were marked increases in BA transporters in the large intestine. Increased GLP-1 levels and gallbladder size were observed in GF mice, suggesting activation of TGR5 signaling. In summary, the GF condition results in increased expression of BA transporters in the colon, resulting in 1) an increase in total BA concentrations in tissues, 2) a change in BA composition to favor an increase in non-12a-OH BAs, and 3) activation of TGR5 signaling with increased gallbladder size and GLP-1.

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Composition of cecal bile acids in ex‐germfree mice inoculated with human intestinal bacteria

Cited by 18 publications

References 33 publications

Characterization of Bacteria, Clostridia and<i> Bacteroides</i> in Faeces of Vegetarians Using qPCR and PCR-DGGE Fingerprinting

Characterization of Bacteria, Clostridia and<i> Bacteroides</i> in Faeces of Vegetarians Using qPCR and PCR-DGGE Fingerprinting

Deoxycholic acid formation in gnotobiotic mice associated with human intestinal bacteria

Importance of Large Intestine in Regulating Bile Acids and Glucagon-Like Peptide-1 in Germ-Free Mice

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