Department of Microbiology and Immunology; Uniformed Services University of the Health Sciences; Bethesda, MD USA.
Gut Microbes. 2014 Jan-Feb;5(1):40-3. doi: 10.4161/gmic.26263. Epub 2013 Jan 1.
The health benefits of a high fiber diet (HFD) result in part from the action of metabolic end products made by gut commensals on the host epithelium. Butyrate is one such beneficial metabolite; however, butyrate paradoxically enhances the capacity of Escherichia coli-produced Shiga toxin type 2 (Stx2) to kill tissue culture cells. We recently showed that mice fed an HFD exhibited increased butyrate in gut contents and had an altered intestinal microbiota with reduced numbers of Escherichia species. Furthermore, mice fed an HFD and infected with Stx-producing E. coli (STEC) were colonized to a higher degree, lost more weight and succumbed to infection at greater rates compared with STEC-infected low fiber diet animals. The HFD animals showed higher levels of the Stx receptor globotriaocylceramide (Gb3) in both the gut and kidneys. We speculate that an HFD that leads to increased intestinal butyrate and Gb3 in the intestines and kidneys may explain the higher rate of the hemolytic uremic syndrome in females over males.
高纤维饮食（HFD）对健康的益处部分源于肠道共生菌在宿主上皮细胞上产生的代谢终产物的作用。丁酸就是这样一种有益的代谢物；然而，丁酸出人意料地增强了大肠杆菌产生的志贺毒素 2 型（Stx2）杀死组织培养细胞的能力。我们最近发现，喂食 HFD 的小鼠肠道内容物中丁酸含量增加，肠道微生物群发生改变，大肠杆菌数量减少。此外，与感染产志贺毒素大肠杆菌（STEC）的低纤维饮食动物相比，喂食 HFD 并感染 STEC 的小鼠定植程度更高，体重减轻更多，并且感染死亡率更高。HFD 动物的肠道和肾脏中的志贺毒素受体神经节苷脂 Gb3 水平更高。我们推测，导致肠道中丁酸和 Gb3 增加的 HFD 可能解释了女性溶血尿毒综合征发病率高于男性的原因。
