Development of an innovative method for reducing colon-cancer-inducing secondary bile acid formation through enhancement of anaerobic respiration of the intestinal bacteria

一些在大肠中形成的次级胆汁酸被认为是结肠癌的危险因素。在这项研究中，一种新的方法，减少这种二级胆汁酸形成的还原代谢的肠道微生物进行了调查。我们测试了通过引入无氧呼吸来增强负责肠道微生物的氧化代谢是否可以减少目标次级胆汁酸。因此，给大鼠喂食补充丙酸钠的饮食以增强肠道微生物的无氧呼吸。虽然实验结果表明，富马酸可能降低了诱导结肠癌的代表性次级胆汁酸脱氧胆酸的相对丰度，但观察到的效果并不实际适用，因为富马酸需要高剂量（饲料的5~10%），这导致了大鼠实验中的腹泻。因此，可能需要改进的浓缩物进料方法，例如封装，以实现这一目标。

Some secondary bile acids formed in the large intestine are known as a riskfactor of colon cancer. In this study a novel method that reduces such secondary bile acids formed by thereductive metabolism of gut microbes were investigated. We tested if the enhancement of oxidativemetabolism of the responsible gut microbes by the introduction of anaerobic respiration can reduce thetarget secondary bile acids. Thus, rats were fed sodium fumarate-supplemented diet to enhanceanaerobic respiration of the gut microbes. Although the results suggested a possibility of decreasingrelative abundance of deoxycholic acid, a representative colon-cancer-inducing secondary bile acid, theobserved effects were not practically applicable, because high dose of fumarate was required (5~10% ofthe diet), which resulted in the diarrhea in rats experiments. Therefore, improved method of fumaratefeeding, e.g. encapsulation, might be necessary to achieve this goal.