Department of Mathematics and Statistics, Williams College, Williamstown, Massachusetts, USA.
Department of Biobehavioral Nursing and Health Informatics, University of Washington, Seattle, Washington, USA.
Neurogastroenterol Motil. 2023 May;35(5):e14545. doi: 10.1111/nmo.14545. Epub 2023 Feb 13.
Imbalance of the tryptophan (TRP) pathway may influence symptoms among patients with irritable bowel syndrome (IBS). This study explored relationships among different components that contribute to TRP metabolism (dietary intake, stool metabolite levels, predicted microbiome metabolic capability) in females with IBS and healthy controls (HCs). Within the IBS group, we also investigated relationships between TRP metabolic determinants, Bifidobacterium abundance, and symptoms of IBS.
Participants with IBS (Rome III) and HCs completed a 28-day diary of gastrointestinal symptoms and a 3-day food record for TRP intake. They provided a stool sample for shotgun metagenomics, 16 S rRNA analyses, and quantitative measurement of TRP by mass spectrometry.
Our cohort included 115 females, 69 with IBS and 46 HCs, with a mean age of 28.5 years (SD 7.4). TRP intake (p = 0.71) and stool TRP level (p = 0.27) did not differ between IBS and HC. Bifidobacterium abundance was lower in the IBS group than in HCs (p = 0.004). Predicted TRP metabolism gene content was higher in IBS than HCs (FDR-corrected q = 0.006), whereas predicted biosynthesis gene content was lower (q = 0.045). Within the IBS group, there was no association between symptom severity and TRP intake or stool TRP, but there was a significant interaction between Bifidobacterium abundance and TRP intake (q = 0.029) in predicting stool character.
Dietary TRP intake, microbiome composition, and differences in TRP metabolism constitute a complex interplay of factors that could modulate IBS symptom severity.
色氨酸（TRP）代谢途径失衡可能会影响肠易激综合征（IBS）患者的症状。本研究旨在探索 IBS 女性患者和健康对照者（HCs）的 TRP 代谢（饮食摄入、粪便代谢产物水平、预测微生物组代谢能力）的不同组成部分之间的关系。在 IBS 组中，我们还研究了 TRP 代谢决定因素、双歧杆菌丰度与 IBS 症状之间的关系。
符合罗马 III 标准的 IBS 患者和 HCs 完成了 28 天胃肠道症状日记和 3 天 TRP 饮食摄入量记录。他们提供了粪便样本进行宏基因组学、16S rRNA 分析和 TRP 的质谱定量测量。
我们的队列包括 115 名女性，其中 69 名患有 IBS，46 名 HCs，平均年龄为 28.5 岁（标准差 7.4）。IBS 和 HCs 之间的 TRP 摄入量（p=0.71）和粪便 TRP 水平（p=0.27）没有差异。IBS 组的双歧杆菌丰度低于 HCs（p=0.004）。与 HCs 相比，IBS 组预测的 TRP 代谢基因含量更高（经 FDR 校正 q=0.006），而预测的生物合成基因含量较低（q=0.045）。在 IBS 组中，症状严重程度与 TRP 摄入量或粪便 TRP 之间没有关联，但双歧杆菌丰度与 TRP 摄入量之间存在显著的交互作用，可预测粪便特征（q=0.029）。
饮食 TRP 摄入量、微生物组组成和 TRP 代谢差异构成了可能调节 IBS 症状严重程度的复杂因素相互作用。
