Psychological co-morbidities in irritable bowel syndrome (IBS) have been widely recognized, whereas less is known regarding the role of gut microbial and host metabolic changes in clinical and psychological symptoms in IBS. A total of 70 diarrhoea-predominant IBS (IBS-D) patients and 46 healthy controls were enrolled in this study. Stool and urine samples were collected from both groups for 16S rRNA gene sequencing and metabolomic analysis. The results showed that fecal microbiota in IBS-D featured depleted Faecalibacterium (adjusted P = 0.034), Eubacterium rectale group (adjusted P = 0.048), Subdoligranulum (adjusted P = 0.041) and increased Prevotella (adjusted P = 0.041). O-ureido-L-serine, 3,4-dihydroxybenzenesulfonic acid and (R)-2-Hydroxyglutarate demonstrated lower urinary concentrations in IBS-D patients. We further built correlation matrices between gut microbe abundance, differentiated metabolite quantities and clinical parameters. Dialister manifested negative association with IBS severity (r = − 0.285, P = 0.017), anxiety (r = − 0.347, P = 0.003) and depression level (r = − 0.308, P = 0.010). Roseburia was negatively associated with IBS severity (r = − 0.298, P = 0.012). Twenty metabolites correlated with anxiety or depression levels, including 3,4-dihydroxymandelaldehyde with SAS (r = − 0.383, P = 0.001), 1-methylxanthine with SDS (r = − 0.347, P = 0.004) and 1D-chiro-inositol with SAS (r = − 0.336, P = 0.005). In analysis of microbe-metabolite relationship, 3,4-dihydroxymandelaldehyde and 1-methylxanthine were negatively correlated with relative abundance of Clostridiumsensu stricto. Our findings demonstrated altered microbial and metabolomic profiles associated with clinically and psychological symptoms in IBS-D patients, which may provide insights for further investigations.

中文翻译：

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与腹泻为主的IBS患者的抑郁症和焦虑症合并症相关的微生物和代谢组学特征。

肠易激综合症（IBS）的心理合并症已得到广泛认可，而在IBS中，肠道微生物和宿主代谢变化在临床和心理症状方面的作用鲜为人知。共有70位腹泻为主的IBS（IBS-D）患者和46位健康对照参加了这项研究。从两组中收集粪便和尿液样本以进行16S rRNA基因测序和代谢组学分析。结果显示，IBS-D中的粪便微生物群的特征是枯草杆菌（已调整P = 0.034），直肠真细菌组（已调整P = 0.048），十二指肠下尿杆菌（已调整P = 0.041）和普氏杆菌增加（已调整P = 0.041）。在IBS-D患者中，O-脲基-L-丝氨酸，3,4-二羟基苯磺酸和（R）-2-羟基戊二酸酯显示出较低的尿液浓度。我们进一步建立了肠道微生物丰度，差异化代谢物数量与临床参数之间的相关矩阵。透析液表现出与IBS严重程度（r = − 0.285，P = 0.017），焦虑症（r = − 0.347，P = 0.003）和抑郁水平（r = − 0.308，P = 0.010）负相关。玫瑰果与IBS严重程度呈负相关（r = − 0.298，P = 0.012）。二十种与焦虑或抑郁水平相关的代谢物，包括3,4-二羟基扁桃醛和SAS（r =-0.383，P = 0.001），1-甲基黄嘌呤和SDS（r =-0.347，P = 0.004）和一维手性肌醇SAS（r = − 0.336，P = 0.005）。在微生物与代谢物的关系分析中，3,4-二羟基扁桃醛和1-甲基黄嘌呤与严格梭状芽胞杆菌的相对丰度呈负相关。