代谢手术对肠道菌群/TMA/FMO3/TMAO通路的影响及机制研究

Metabolic surgery effectively alleviate obesity and diabetes. The long-term impact of its regulation of gut microbiota on metabolism attract more attention but the exact mechanism remains unknown. Trimethylamine-N-oxide (TMAO), a gut-derived metabolite, has recently emerged as a candidate risk factor for cardiovascular disease and other chronic metabolic disease. However, whether TMAO is a causative agent in human disease development and progression, or a simply marker of an underlying pathology, remains inconclusive. In our previous study,we established the metabolic surgery model of Zucker diabetes fatty rats (ZDF), observed the characteristics of gut microbiota changes after surgery, and found the plasma TMAO positively collected with blood glucose. In this study, we would like to deeply reseach the bacteria/ trimethylamine(TMA)/ flavin-containing monooxygenase 3 (FMO3) /TMAO pathway. We aim to observe the changes of confounding factors such as anatomical changes, gut microbiota, TMA precursor material, FMO3 function, and TMAO kidney clearance, and their collection with metabolic benefit before and after sugery. Then, the stable intestinal contents will be transplanted into sterile Mice to further validat the modification. Through this study,firstly, the changes of gut microbiota/TMA/FMO3/TMAO pathway after metabolic surgery were elucidated, which provided a theoretical basis for the mechanism of metabolic surgery and the prognosis of complications. On the other hand, through the metabolic surgery model, the association between the gut microbiota /TMA/FMO3/TMAO pathway and the metabolic disease is elucidated, providing some potential way for the regulation of TMAO level in vivo and the control of glucose metabolism and cardiovascular risk.

代谢手术有效缓解肥胖及糖尿病，调控肠道菌群长期影响代谢倍受关注，确切机制未明。菌群代谢产物氧化三甲胺(TMAO)与代谢疾病关系密切，因果未定。我们在前期建立的肥胖糖尿病大鼠代谢手术模型上，观察到肠道菌群特征性改变及血浆TMAO与血糖正相关。我们在此基础上拟对菌群/三甲胺(TMA)/ 含黄素单氧化酶3(FMO3)/TMAO通路深入研究，从解剖改变、肠道菌群、TMA前体物质、肝脏FMO3作用、TMAO肾脏清除等层面观察手术前后影响因素变化及与代谢效益之间关联分析，并将术后稳定的肠道菌群移植至无菌小鼠进一步验证。通过该研究，一方面阐明代谢手术后菌群/TMA/FMO3/TMAO通路变化趋势，为代谢手术肠道作用机制及缓解并发症预后提供理论基础；另一方面，借用代谢术式动物模型平台研究菌群/TMA/FMO3/TMAO通路与代谢疾病的关联，为寻找调控体内TMAO水平进而控制糖代谢及心血管风险提供一定可能。

代谢手术有效缓解肥胖及糖尿病，调控肠道菌群长期影响代谢倍受关注，确切机制未明。菌群代谢产物氧化三甲胺(TMAO)与代谢疾病关系密切，因果未定。我们在前期建立的肥胖糖尿病大鼠代谢手术模型上，观察到肠道菌群特征性改变及血浆TMAO与血糖正相关。我们在此基础上拟对菌群/三甲胺(TMA)/ 含黄素单氧化3(FMO3)/TMAO通路深入研究，从解剖改变、肠道菌群、TMA前体物质、肝脏FMO3作用、TMAO肾脏清除等层面观察手术前后影响因素变化及与代谢效益之间关联分析。为进一步验证，我们进行如下研究：（1）建立了C57雄性小鼠行高脂饮食诱导造模和OB雄性小鼠造模，建立了一个良好的研究减重手术及肥胖糖尿病的平台，并观察到SG（袖状胃切除术）对两种小鼠糖脂代谢均有明显改善作用，术后肠道菌群多样性结构均出现特征性变化。（2）进一步对SG术后肠道菌群-FMO3-TMAO变化趋势进行比较，开展肠道微生物宏基因组测序，并进行多组学联合关联与模型预测分析。（3）针对SG术后肝脏TMAO生成相关及下游通路蛋白比较实时定量PCR技术和免疫印迹方法（Western blot）测定肝脏组织中FMO3、FoxO1水平，并与随之发生的糖脂代谢指标、TMAO及相关物质作关联分析。该研究阐明了代谢手术后菌群/TMA/FMO3/TMAO通路变化趋势，为代谢手术肠道作用机制及缓解并发症预后提供理论基础，以及将来寻求有效的非手术治疗方法提供理论基础。