Fecal Metabolites As Non-Invasive Biomarkers of Gut Diseases.

Recent studies have shown the importance of the human intestinal microbiome in maintaining a healthy gastrointestinal tract, as well as in the development of pathological processes. The intestinal microbiome manifests itself primarily as fecal metabolites. In the past decade, there has been growing interest in studying its composition, which for the most part had to do with the possibility of using the metabolomic analysis in clinical diagnosis. In contrast to the comprehensive description of blood serum, urine, saliva, and cerebrospinal fluid metabolites, data on fecal metabolites is sparse. Despite the instrumental and methodological achievements in the metabolomic analysis in general, the analysis of fecal metabolome remains less well developed, mainly because of the inhomogeneity of its composition and the lack of standardized methods for collecting, processing, and analyzing fecal samples. This review summarizes data on methods for studying and describing various groups of fecal metabolites. It also assesses their potential as tools in the diagnosis of gastrointestinal diseases.

[Evaluation of metabolites levels in feces of patients with inflammatory bowel diseases]. / Otsenka urovnia metabolitov v fekaliiakh patsientov s vospalitel'nymi zabolevaniiami kishechnika.

Inflammatory bowel diseases (IBD), which include ulcerative colitis (UC) and Crohn's disease (CD), are chronic intestinal inflammatory disorders with an unknown etiology. They are characterized by chronic recurrent inflammation of the intestinal mucosa and lead to a significant decrease in the quality of life and death of patients. IBD are associated with suppression of normal intestinal microflora, including a decrease in bacteria, producers of short chain fatty acids (SCFAs), exhibiting anti-inflammatory and protective properties. Among the various methods of intestinal microflora correction, fecal microbiota transplantation (FMT), which engrafts the fecal microbiota from a healthy donor into a patient recipient, is of a particular interest. As a result, a positive therapeutic effect is observed, accompanied by the restoration of the normal intestinal microflora of the patient. A significant drawback of the method is the lack of standardization. Metabolites produced by intestinal microflora, namely SCFAs, allow objective assessment of the functional state of the intestinal microbiota and, consequently, the success of the FMT procedure. Using gas chromatography and nuclear magnetic resonance spectroscopy techniques, we have analyzed concentrations and molar ratios of SCFAs in fecal samples of 60 healthy donors. Results were in good accord when comparing two methods as well as with published data. Analysis of SCFAs in feces of patients with UC (19 patients) and CD (17 patients) revealed a general decrease in the concentration of fatty acids in the experimental groups with significant fluctuations in the values in experimental groups compared to control group of healthy donors. On the limited group of IBD patients (6 patients with UC and 5 patients with CD) concentration of SCFAs before and within 30 days of observation after FMT was determined. It was shown that FMT had a significant impact on the SCFAs levels within 1 month term; tendency to reach characteristics of healthy donors is unambiguously traced for both diseases.