Describing the fecal metabolome in cryogenically collected samples from healthy participants

Abstract

Introduction:The chemical composition of feces plays an important role in human metabolism. Metabolomics and lipidomics are valuable tools for screening the metabolite composition in feces. Here we set out to describe fecal metabolite composition in healthy participants in frozen stools.Methods: Frozen stool samples were collected from 10 healthy volunteers and cryogenically drilled in four areas along the specimen. Polar metabolites were analyzed using derivatization followed by two-dimensional gas chromatography and time of flight mass spectrometry. Lipids were detected using ultra highperformance liquid chromatography coupled with quadruple time-of-flight mass spectrometry. The technical variation threshold was set to 30% in pooled quality control samples and metabolite variation was then assessed in four areas per specimen. A data-generated network using metabolites found in all areas was computed for healthy participants.Results: 2326 metabolic features were detected. Out of a total of 298 metabolites that were annotated we report here 185 that showed a technical variation of x< 30%. These metabolites included amino acids, fatty acid derivatives, carboxylic acids and phenolic compounds. Lipids predominantly belonged to the groups of diacylglycerols, triacylglycerols and ceramides. Metabolites varied between sampling areas (14%-80%). A network using metabolites present in all areas showed two main clusters, DAG lipids and phenyllactic acid. Conclusions:In feces from healthy participants, the main groups detected were phenolic compounds, ceramides, diacylglycerols and triacylglycerols. Metabolite levels differed considerably depending on the sampling area.

Effect of Dietary Protein Levels on Dynamic Changes and Interactions of Ruminal Microbiota and Metabolites in Yaks on the Qinghai-Tibetan Plateau

“…Galactonic acid (the main component of pectin) was positively associated with Christensenellaceae in this study, suggesting that Christensenellaceae may be useful in degrading dietary polysaccharides. Moreover, 3phenyllactic acid has antimicrobial properties and is related to phenylalanine metabolism, and phenylalanine can be catalyzed by phenylalanine hydroxylase to produce tyrosine (Yang et al, 2018;Trost et al, 2020). Our results suggest that Prevotellaceae and Bacteroidales exert positive and negative effects on the tyrosine metabolic pathway, respectively.…”

Milk polar lipids favorably alter circulating and intestinal ceramide and sphingomyelin species in postmenopausal women

“…In addition, the digestion of SM being slow and incomplete, it may induce an important increase of non-digested SM and non-absorbed Cer in the lumen content (3,30), which may explain the present results. Moreover, fecal metabolites, including the various lipid species normally found in feces, may originate directly from food, but also from host cells, bacterial cell components or indirectly from the molecular conversion of SP by gut microorganisms or host enzymes (37). In a recent study performed in healthy patients, plasma and fecal lipidomic analyses demonstrated that the lipid fraction of fecal samples contains significant amounts of Cer species with only two SM species detected, while plasma samples commonly contain significant amounts of several SM species and lower quantities of Cer (37,38).…”

“…Moreover, fecal metabolites, including the various lipid species normally found in feces, may originate directly from food, but also from host cells, bacterial cell components or indirectly from the molecular conversion of SP by gut microorganisms or host enzymes (37). In a recent study performed in healthy patients, plasma and fecal lipidomic analyses demonstrated that the lipid fraction of fecal samples contains significant amounts of Cer species with only two SM species detected, while plasma samples commonly contain significant amounts of several SM species and lower quantities of Cer (37,38). Herein, we chose to determine the concentration of In ileostomy patients, we report higher total SM amount in ileal content compared to total Cer, while total Cer was largely more abundant in the fecal samples compared to total SM.…”

A paired liver biopsy and plasma proteomics study reveals circulating biomarkers for alcohol-related liver disease

“…For the healthy and ALD cohorts, participant recruitment protocol including inclusion and exclusion criteria, setting and locations where data were collected can be found in the original report (Thiele et al, 2016;Thiele et al, 2018;Trošt et al, 2020). The same applies for sample-and clinical data collection procedure, detailed description of the cohort characteristics and anything related to the original clinical study design.…”