Tryptophan Metabolites in Irritable Bowel Syndrome: An Overnight Time-course Study

Area of Science:

• Gastroenterology
• Neuroscience
• Metabolomics

Background:

• Irritable bowel syndrome (IBS) is frequently associated with poor sleep quality.
• The relationship between sleep disturbances and tryptophan (Trp) metabolites in IBS remains largely unexplored.

Purpose of the Study:

• To compare serum Trp metabolite profiles in women with IBS and healthy controls (HCs).
• To investigate associations between Trp metabolites, IBS symptoms, sleep indices, and stress markers (cortisol, ACTH) in IBS patients.

Main Methods:

• Targeted liquid chromatography mass spectrometry (LC-MS) profiling of serum Trp metabolites.
• Blood samples collected over 80-minute intervals during a sleep laboratory protocol following a stressor in 38 IBS subjects and 21 HCs.
• Analysis of metabolite levels across different sleep stages and correlation with symptom diaries, sleep measures, and hormonal data.

Main Results:

• Significant differences in Trp metabolite profiles were observed between IBS patients and HCs (P = 0.014).
• IBS patients exhibited higher nicotinamide and lower indole-3-lactic acid levels compared to HCs.
• Melatonin and indole-3-acetic acid levels correlated with sleep measures, while kynurenine and kynurenic acid showed associations with ACTH and cortisol/ACTH ratios.

Conclusions:

• Nighttime tryptophan metabolite patterns may offer insights into the interplay of poor sleep and stress in IBS.
• Further research into the mechanistic roles of these metabolites in IBS pathophysiology is warranted.