Dataset Information

Prebiotic inulin-type fructans induce specific changes in the human gut microbiota

ABSTRACT: ObjectiveContrary to the long-standing prerequisite of inducing selective (i.e. bifidogenic) effects, recent findings suggest that prebiotic interventions lead to ecosystem-wide microbiota shifts. Yet, a comprehensive characterization of this process is still lacking. Here, we apply 16S rDNA microbiota profiling and matching (GC-MS) metabolomics to assess the consequences of inulin fermentation both on the composition of the colon bacterial ecosystem and fecal metabolites profiles.DesignFecal samples collected during a double blind, randomized, cross-over intervention study (NCT02548247) set up to assess the effect of inulin consumption on stool frequency in healthy adults with mild constipation were analyzed. Fecal microbiota composition and metabolite profiles were linked to the study’s clinical outcome as well as to quality-of-life measurements recorded.ResultsWhile fecal metabolite profiles were not significantly altered by inulin consumption, our analyses did detect a modest effect on global microbiota composition. At the same time, specific inulin-induced changes in relative abundances of Anaerostipes, Bilophila, and Bifidobacterium were identified. The observed decrease in Bilophila abundances following inulin consumption was associated with both softer stools and a favorable change in constipation-specific quality of life measures.ConclusionsEcosystem-wide analysis of the effect of a dietary intervention with prebiotic inulin-type fructans on the colon microbiota revealed that this effect is specifically associated to three genera, one of which (Bilophila) representing a promising novel target for mechanistic research.

PROVIDER: EGAS00001002173 | EGA |

REPOSITORIES: EGA

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Effect of consumption of chicory inulin on bowel function in healthy subjects with constipation: a randomized, double-blind, placebo-controlled trial.

Micka Antje A Siepelmeyer Anne A Holz Anja A Theis Stephan S Schön Christiane C

International journal of food sciences and nutrition 20160805 1

Constipation is among the most common health impairments in Western countries. This study aimed to determine the effect of the chicory-derived fermentable dietary fiber Orafti<sup>®</sup> Inulin on stool frequency in healthy subjects with constipation. The study was conducted according to recent guidance documents for investigating bowel function and used a randomized, double-blind, placebo-controlled, cross-over design with a 2-week wash-out phase. Each study period comprised a run-in phase fol ...[more]

PMID: 27492975

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Project description:Study 1: Transcriptomic profiles in colon tissue from inflammatory bowel diseases patients in relation to N-nitroso compound exposure and colorectal cancer risk Study 1: N-nitroso compounds (NOC) have been suggested to play a role in human cancer development but definitive evidence is still lacking. In this study we investigated gene expression modifications induced in human colon tissue in relation to NOC exposure to gain insight in the relevance of these compounds in human colorectal cancer (CRC) development. Since there are indications that inflammation stimulates endogenous NOC formation, the study population consisted of patients with inflammatory bowel disease (IBD) and irritable bowel syndrome patients as controls without inflammation. Strong transcriptomic differences were identified in colonic biopsies from IBD patients and compared to controls that enhance the understanding of IBD pathophysiology. However, fecal NOC levels were not increased in IBD patients, suggesting that inflammation did not stimulate NOC formation. By relating gene expression changes of all subjects to fecal NOC levels, we did, however, identify a NOC exposure-associated transcriptomic response that suggests that physiological NOC concentrations may induce genotoxic responses and chromatin modifications in human colon tissue, both of which are linked to carcinogenicity. In a network analysis, chromatin modifications were linked to 11 significantly modulated histone genes, pointing towards a possible epigenetic mechanism that may be relevant in comprehending the molecular basis of NOC-induced carcinogenesis. We conclude that NOC exposure is associated with gene expression modifications in the colon that may increase CRC risk in humans. Study 2: Red meat intake-induced increases in fecal water genotoxicity correlate with pro-carcinogenic gene expression changes in the human colon Study 2: Red meat consumption is associated with an increased colorectal cancer (CRC) risk, which may be due to an increased endogenous formation of genotoxic N-nitroso compounds (NOCs). To assess the impact of red meat intake on potential risk factors of CRC, we investigated the effect of a 7-day dietary red meat intervention in human subjects on endogenous NOC formation and fecal water genotoxicity in relation to transcriptomic changes induced in colonic tissue. In order to evaluate the potential effect of an inflamed colon on endogenous nitrosation, the study population consisted of inflammatory bowel disease (IBD) and irritable bowel syndrome (IBS) control subjects without inflammation. The intervention had no effect on fecal NOC formation but fecal water genotoxicity significantly increased in response to red meat intake. Since IBD patients showed no difference in fecal NOC formation or fecal water genotoxicity levels as compared to IBS controls, for transcriptomic analyses, all subjects were grouped together. Genes significantly correlating with the increase in fecal water genotoxicity were involved in biological pathways indicative of genotoxic effects, including modifications in DNA damage, cell cycle, and apoptosis pathways. Moreover, WNT signaling and nucleosome remodeling pathways were modulated that are known to play a part in the carcinogenic process in the human colon. These results are in line with a possible oxidative effect of dietary heme. We conclude that the gene expression changes identified in this study corroborate the genotoxic potential of diets high in red meat and point towards a possible risk of CRC development in humans. The study investigated transcription levels in human colon biopsies obtained during a colonoscopic exam in 32 subjects suffering from either inflammatory bowel disease (IBD) or irritable bowel syndrome (IBS). IBS patients served as control patients for comparison with IBD patients (see Study 1). 12 of these patients (6 IBD and 6 IBS) also followed a 7-day diet high in red meat (300 grams/day) after which a second colonscopic exam was performed to obtain colon biopsies to investigate the effect of the red meat intervention (Study 2). For each subject, cRNA copies of mRNA isolated from the colon biopsies were labeled with one dye (Cy3) and each sample was hybridized on a separate array. One replicate per subject or before/after red meat intervention (so 44 arrays in total, i.e. 20 before patients and 12 before and after patients).

Dataset Information

Prebiotic inulin-type fructans induce specific changes in the human gut microbiota

Publications

Effect of consumption of chicory inulin on bowel function in healthy subjects with constipation: a randomized, double-blind, placebo-controlled trial.

Similar Datasets

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