氧化三甲胺分布特征及其与肠道菌群的关联性

目的了解中国社区人群氧化三甲胺（TMAO）分布水平，分析TMAO与心脑血管风险因素的相关性及探讨TMAO与肠道菌群关系。方法研究对象为颈动脉彩超检查无动脉硬化斑块的体检人群，共纳入181例，男96人，年龄30~73岁。采集血清标本，运用稳定同位素内标液质联用法检测TMAO。采集粪便标本，通过Illumina高通量测序检测16S rRNA基因V4可变区，进行肠道菌群检测。采用SPSS分析TMAO与心脑血管疾病相关风险因素相关性，运用QIIME及LEfSe分析肠道菌群，找出与TMAO相关的菌属。结果健康人群中TMAO中值为2.66（1.96~4.91）μmol/L，呈偏态分布。TMAO不同水平组间传统心脑血管疾病风险因子没有差异，也没有特征性肠道菌群结构。通过统计发现TMAO与BMI及肠道菌群中的梭菌目（Clostridiales）下属的厌氧孢杆菌属（Anaerosporobacter）、梭菌属（Clostridiales）、考拉杆菌属（Phascolarctobacterium）、颤杆菌克属（Oscillibacter）及拟杆菌目（Bacteroidales）下属的Alistipes有相关性。结论中国人群TMAO水平普遍较低，TMAO水平与传统心脑血管疾病风险因子没有显著相关性，不同TMAO水平组间肠道菌群组成没有差异，个别菌属与TMAO水平有相关关系。

Distribution characteristics of trimethylamine N- oxide and its association with gut microbiota

Objective To analyze the distribution of trimethylamine N-oxide (TMAO) in healthy adults with different riskfactors and explore its association with gut microbiota. Methods We collected fasting blood samples and fresh fecal samplesfrom 181 subjects without atherogenesis in the carotid arteries. Plasma TMAO levels of the subjects were determined usingstable isotope dilution liquid chromatography-tandem mass spectrometry (LC-MS). The fecal DNA was extracted, and the 16SrRNA V4 tags were amplified and sequenced by Illumina HiSeq 2000. The association between TMAO and classicalcardiovascular risk factors were analyzed. Gut microbial community structure was analyzed with QIIME, and LEfSe was usedto identify the biomarkers. Results The median (IQR) TMAO level was 2.66 (1.96-4.91) μmol/L in the subjects. TMAO level wassignificantly correlated with body mass index and operational taxonomic units (OTU). Individuals with high TMAO levelswere found to have abundant Clostridiales, Phascolarctobacterium, Oscillibacter, and Alistipes but less abundant Anaerosprobacter.Conclusion Chinese subjects have in general low levels of TMAO. TMAO levels are not significantly correlated with theclassical cardiovascular risk factors or the gut microbial structures.