The intestinal microbiota is recognised as an important player in the development and maintenance of obesity. Most studies focus on faecal microbiota because of its accessibility. However, the small intestine is a major site for nutrient sensing and absorption and few studies have examined the composition and function of the microbiota in this segment of the digestive tract. We conducted a clinical research project on 30 age- and sex-matched participants with (N=15) and without (N=15) obesity. Duodenojejunal fluid was obtained by aspiration during fibroscopy. Phenotyping included clinical variables related to metabolic status, lifestyle and psychosocial factors using validated questionnaires. Metagenomic analyses of the oral, duodenojejunal and faecal microbiome, as well as metabolomic data from duodenojejunal fluid and faeces, were integrated with clinical and lifestyle data. The results show associations between duodenojejunal microbiota and lifestyle as well as clinical phenotypes. These associations had larger effect sizes than the associations between these variables and faecal microbiota. We also observed that the duodenojejunal microbiota of obese patients had a higher diversity. In addition, we observed differences in the abundance of several species of the duodenojejunal microbiota between control individuals and patients suffering from obesity. In conclusion, our results support the relevance of studying the role of the small intestinal microbiota in the development of metabolic diseases.

中文翻译：

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十二指肠空肠微生物组与口腔和粪便微生物组的比较分析揭示了其在人类严重肥胖中的作用。

肠道微生物群被认为是肥胖发生和维持的重要参与者。大多数研究都集中在粪便微生物群上，因为它的可及性。然而，小肠是营养物质感知和吸收的主要部位，很少有研究检查消化道这一部分微生物群的组成和功能。我们对 30 名年龄和性别匹配的肥胖 (N=15) 和非肥胖 (N=15) 参与者进行了一项临床研究项目。纤维镜检查期间通过抽吸获得十二指肠空肠液。使用经过验证的问卷进行表型分析，包括与代谢状态、生活方式和心理社会因素相关的临床变量。将口腔、十二指肠空肠和粪便微生物组的宏基因组分析，以及十二指肠空肠液和粪便的代谢组数据与临床和生活方式数据相结合。 结果显示十二指肠空肠微生物群与生活方式以及临床表型之间的关联。这些关联比这些变量与粪便微生物群之间的关联具有更大的效应量。我们还观察到肥胖患者的十二指肠空肠微生物群具有更高的多样性。此外，我们观察到对照个体和肥胖患者之间几种十二指肠空肠微生物群的丰度存在差异。总之，我们的结果支持研究小肠微生物群在代谢疾病发展中的作用的相关性。