Folate synthesized by bacteria in the human upper small intestine is assimilated by the host
Folate synthesized by bacteria in the human upper small intestine is assimilated by the host
复制标题
DOI：
10.1053/gast.1996.v110.pm8613033
复制
发表时间：
1996-04-01
期刊：
影响因子：
29.4
通讯作者：
Rosenberg, IH
中科院分区：
文献类型：
--
作者：
Camilo, E;Zimmerman, J;Rosenberg, IH
背景与目的：已知一些肠道菌群可以合成叶酸。本研究的目的是确定由小肠菌群合成的叶酸是否被人体宿主吸收。方法：对萎缩性胃炎患者和健康志愿者给予奥美拉唑前后进行研究。双腔灌注管置于十二指肠。灌注h -3标记的对氨基苯甲酸，细菌叶酸合成的前体底物。进行下游肠道抽吸和48小时尿液收集。结果：萎缩性胃炎和奥美拉唑与十二指肠pH值和小肠菌群升高有关。从肠道抽吸物中分离出细菌合成的叶酸。奥美拉唑组尿液中分离出叶酸的主要代谢物5-甲基四氢叶酸（Tritiated 5-methyltetrahydrofolate），奥美拉唑组尿液中分离出的叶酸含量高于未用药组（P < 0.01）；萎缩性胃炎患者尿液中5-甲基四氢叶酸的氚化量也同样升高。结论：(1)萎缩性胃炎引起的轻度细菌过度生长和服用奥美拉唑与小肠腔内叶酸的新生合成有关；(2)人体宿主吸收并使用其中的一些叶酸；(3)这一来源对叶酸营养的贡献尚不清楚。
Background & Aims: Some intestinal flora are known to synthesize folate. The aim of this study was to determine whether folate synthesized by small intestinal flora is assimilated by the human host. Methods: Subjects with atrophic gastritis and healthy volunteers were studied before and after omeprazole administration. A double-lumen perfusion tube was placed in the duodenum. H-3-labeled P-aminobenzoic acid, a precursor substrate for bacterial folate synthesis, was perfused. Downstream intestinal aspirates and a 48-hour urine collection were obtained. Results: Atrophic gastritis and omeprazole administration were associated with increases in duodenal pH and in small intestinal flora. Bacterially synthesized folates were isolated from the intestinal aspirates. Tritiated 5-methyltetrahydrofolate, a major metabolite of folate, was isolated from the urine of omeprazole-treated subjects in greater quantities than from drug-free subjects (P < 0.01); the quantity of tritiated 5-methyltetrahydrofolate in the urine of the subjects with atrophic gastritis was similarly elevated. Conclusions: (1) Mild bacterial overgrowth caused by atrophic gastritis and administration of omeprazole are associated with de novo folate synthesis in the lumen of the small intestine; (2) the human host absorbs and uses some of these folates; and (3) the contribution to folate nutriture from this source remains unclear.