Treem W R, Ahsan N, Kastoff G, Hyams J S
Division of Pediatric Gastroenterology and Nutrition, Duke University Medical Center, Durham, North Carolina, USA.
J Pediatr Gastroenterol Nutr. 1996 Oct;23(3):280-6. doi: 10.1097/00005176-199610000-00013.
Colonic bacterial production of short-chain fatty acids (SCFA) plays an important role in the salvage of unabsorbed carbohydrate and in colonic absorption of electrolytes and water. The objective of this study was to determine whether patients with diarrhea-predominant irritable bowel syndrome (DP-IBS) have a different pattern and rate of fermentation of carbohydrate and fiber to SCFA compared with controls. Fecal homogenates from 10 patients with DP-IBS and 10 age-matched controls were studied. SCFA were measured by gas chromatography in baseline fecal samples and in fecal homogenates in an in vitro anaerobic fermentation system after incubation with no additional substrate, lactulose, potato starch, citrus pectin, and hemicellulose over a 24-hour period. Net SCFA production rates were calculated for the first 6 h of the incubation period. Patients with DP-IBS had a consistently different pattern of less total SCFA, a lower percentage of acetate (p < 0.05), and a higher proportion of n-butyrate (p < 0.05) than controls. In stool homogenates from both controls and DP-IBS patients, lactulose fermentation resulted in the highest rate of SCFA production followed by pectin, starch, and hemicellulose. However, at all time points, the fecal homogenates from controls generated a higher concentration of total SCFA, acetate, and propionate with all substrates tested. SCFA production rates were higher in controls incubated with lactulose, starch, and hemicellulose. The fecal SCFA profile of patients with DP-IBS is characterized by lower concentrations of total SCFA, acetate, and propionate and a higher concentration and percentage of n-butyrate. Fecal flora from these patients produced less SCFA in an in vitro fermentation system in response to incubations with various carbohydrates and fibers. Differences in SCFA production by colonic bacterial flora in patients with DP-IBS may be related to the development of gastrointestinal symptoms.
结肠细菌产生的短链脂肪酸（SCFA）在未吸收碳水化合物的 salvage 以及结肠对电解质和水的吸收中起着重要作用。本研究的目的是确定腹泻型肠易激综合征（DP-IBS）患者与对照组相比，碳水化合物和纤维发酵生成 SCFA 的模式和速率是否不同。研究了 10 例 DP-IBS 患者和 10 例年龄匹配的对照组的粪便匀浆。通过气相色谱法在基线粪便样本以及在无额外底物、乳果糖、马铃薯淀粉、柑橘果胶和半纤维素孵育 24 小时后的体外厌氧发酵系统中的粪便匀浆中测量 SCFA。计算孵育期前 6 小时的净 SCFA 产生率。与对照组相比，DP-IBS 患者的总 SCFA 含量始终较低，乙酸盐百分比更低（p < 0.05），正丁酸盐比例更高（p < 0.05）。在对照组和 DP-IBS 患者的粪便匀浆中，乳果糖发酵产生的 SCFA 速率最高，其次是果胶、淀粉和半纤维素。然而，在所有时间点，对照组的粪便匀浆在所有测试底物下产生的总 SCFA、乙酸盐和丙酸盐浓度更高。与乳果糖、淀粉和半纤维素孵育的对照组中 SCFA 产生率更高。DP-IBS 患者的粪便 SCFA 谱的特征是总 SCFA、乙酸盐和丙酸盐浓度较低，正丁酸盐浓度和百分比更高。这些患者的粪便菌群在体外发酵系统中对各种碳水化合物和纤维孵育的反应产生的 SCFA 较少。DP-IBS 患者结肠细菌菌群产生 SCFA 的差异可能与胃肠道症状的发生有关。
