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

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.EGA study EGAS00001002173

研究目标：长期以来，益生元干预的预设前提为诱导选择性效应，即双歧杆菌增殖效应，但近期研究证实，益生元干预可引发菌群全生态系统范围的结构变化。目前学界仍缺乏对这一过程的系统性解析。本研究采用16S rDNA菌群谱分析及配套的气相色谱-质谱联用（GC-MS）代谢组学分析，评估菊粉发酵对结肠细菌群落生态系统组成及粪便代谢物谱的影响。
研究设计：本研究对一项双盲随机交叉干预试验（临床试验注册号NCT02548247）所收集的粪便样本展开分析，该试验旨在评估菊粉摄入对轻度便秘健康成年人排便频率的影响。研究将粪便菌群组成与代谢物谱与该试验的临床结局及记录的生活质量评估指标进行关联分析。
研究结果：尽管菊粉摄入未显著改变粪便代谢物谱，但分析发现其对整体菌群组成存在轻度影响。同时，本研究鉴定出菊粉诱导的Anaerostipes（Anaerostipes）、Bilophila（Bilophila）及双歧杆菌属（Bifidobacterium）相对丰度的特异性变化。研究观察到，菊粉摄入后Bilophila（Bilophila）相对丰度的下降，与粪便质地变软及便秘特异性生活质量评分的良性改善显著相关。
研究结论：通过对益生元菊粉型果聚糖膳食干预影响结肠菌群的全生态系统分析，本研究发现该干预效应特异性关联三个菌属，其中Bilophila（Bilophila）为极具潜力的机制研究新靶点。本研究隶属于EGA研究EGAS00001002173。