Intraluminal Precipitation of Bile Acids in Stagnant Loop Syndrome

Northfield, T. C.

doi:10.1136/bmj.2.5869.743

Cited by 10 publications

(2 citation statements)

References 18 publications

(19 reference statements)

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“…Our data indicate that bile acid deconjugation can take place in any segment of the small intestine of conventional healthy mice as a function of the microbial density and composition (Figs. 2a, 3 and 5b), which is consistent with previous findings in animal models and in humans with small intestinal bacterial overgrowth (SIBO) [74][75][76][77][78].…”

Section: Self-reinoculation With Fecal Flora Leads To Altered Bile Acsupporting

confidence: 91%

Self-reinoculation with fecal flora changes microbiota density and composition leading to an altered bile-acid profile in the mouse small intestine

2020

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Background: The upper gastrointestinal tract plays a prominent role in human physiology as the primary site for enzymatic digestion and nutrient absorption, immune sampling, and drug uptake. Alterations to the small intestine microbiome have been implicated in various human diseases, such as non-alcoholic steatohepatitis and inflammatory bowel conditions. Yet, the physiological and functional roles of the small intestine microbiota in humans remain poorly characterized because of the complexities associated with its sampling. Rodent models are used extensively in microbiome research and enable the spatial, temporal, compositional, and functional interrogation of the gastrointestinal microbiota and its effects on the host physiology and disease phenotype. Classical, culture-based studies have documented that fecal microbial self-reinoculation (via coprophagy) affects the composition and abundance of microbes in the murine proximal gastrointestinal tract. This pervasive selfreinoculation behavior could be a particularly relevant study factor when investigating small intestine microbiota. Modern microbiome studies either do not take self-reinoculation into account, or assume that approaches such as single housing mice or housing on wire mesh floors eliminate it. These assumptions have not been rigorously tested with modern tools. Here, we used quantitative 16S rRNA gene amplicon sequencing, quantitative microbial functional gene content inference, and metabolomic analyses of bile acids to evaluate the effects of selfreinoculation on microbial loads, composition, and function in the murine upper gastrointestinal tract.Results: In coprophagic mice, continuous self-exposure to the fecal flora had substantial quantitative and qualitative effects on the upper gastrointestinal microbiome. These differences in microbial abundance and community composition were associated with an altered profile of the small intestine bile acid pool, and, importantly, could not be inferred from analyzing large intestine or stool samples. Overall, the patterns observed in the small intestine of non-coprophagic mice (reduced total microbial load, low abundance of anaerobic microbiota, and bile acids predominantly in the conjugated form) resemble those typically seen in the human small intestine.Conclusions: Future studies need to take self-reinoculation into account when using mouse models to evaluate gastrointestinal microbial colonization and function in relation to xenobiotic transformation and pharmacokinetics or in the context of physiological states and diseases linked to small intestine microbiome and to small intestine dysbiosis.

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Section: Self-reinoculation With Fecal Flora Leads To Altered Bile Acsupporting

confidence: 91%

Self-reinoculation with fecal flora changes microbiota density and composition leading to an altered bile-acid profile in the mouse small intestine

2020

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“…As this is a common occurrence after gastric surgery (Cox, Bond, Podmore, and Rose, 1964) an interrelationship could be postulated. Alternatively, certain bacteria are capable of bile salt deconjugation (Midtvedt and Norman, 1967) and either by depleting the total micellar concentration (Northfield, 1973) or by direct action of free bile acids on the small intestinal mucosa (Gracey, 1971) or on the colon (Soong, Thompson, Paley, and Hess, 1972) diarrhoea could occur. We hope in the future to publish data on a larger number of patients with diarrhoea.…”

Section: Discussionmentioning

confidence: 99%

The effect of vagotomy and drainage on the small bowel flora

Browning¹,

Buchan²,

MacKay³

1974

Gut

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SUMMARY The incidence of small intestinal colonization in unoperated duodenal ulcer patients was low and similar to that in the normal population. The majority of patients seven to 10 days following truncal vagotomy and drainage were colonized whereas none of a control group of patients following simple closure of a perforated duodenal ulcer was colonized. In patients with pyloroplasty, this high incidence fell to control levels on average 18 months postoperatively, but in patients with a gastrojejunostomy, the incidence remained raised probably due to the presence of the afferent loop.Only two patients developed episodic diarrhoea and there was no obvious association with small bowel colonization.

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The Importance of Bile Acids in Human Diseases

Fromm¹,

Hofmann²

1975

Ergebnisse Der Inneren Medizin Und Kinderheilkunde / Advances in Internal Medicine and Pediatrics

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Intraluminal Precipitation of Bile Acids in Stagnant Loop Syndrome

Cited by 10 publications

References 18 publications

Self-reinoculation with fecal flora changes microbiota density and composition leading to an altered bile-acid profile in the mouse small intestine

Self-reinoculation with fecal flora changes microbiota density and composition leading to an altered bile-acid profile in the mouse small intestine

The effect of vagotomy and drainage on the small bowel flora

The Importance of Bile Acids in Human Diseases

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