Age-related changes in production of short-chain fatty acids by gut microbiome in patients without gastroenterological diseases

Rationale: Multiple biological effects of short chain fatty acids (SCFA) and the possibility to modify their composition by probiotics and prebiotics is in the focus of attention of researchers and clinicians. However, big studies with assessment of the whole spectrum of SCFA produced by gut microbiome and calculated indexes of their relative content are lacking.Aim: To determine concentrations and ratios of fecal SCFA (functional activity of the gut microbiome) depending on the age of patients without gastrointestinal disorders.Materials and methods: SCFA fecal concentrations were measured by gas liquid chromatography in 6836 patients aged from 1 month to 85 years without any functional or chronic gastrointestinal pathology, infectious diseases and/or obesity. The time periods with homogenous values of the parameters were determined by identification of constant trends of their means (medians) with 1-month accuracy in children below 5 years of age and with 1-year accuracy in the patients above 1 years of age. The results obtained for the chosen time intervals were compared with Mann-Whitney's test at 95% significance level (p < 0.05).Results: We performed descriptive statistics for absolute and relative content of SCFA and their structural indexes. It was shown that the parameters characterizing functional activity of gut microbiome have different critical stages in their age-related changes. For each parameter, 2 or 3 stages of changes were identified that occurred at early age, mainly before the age of two. The final SCFA structure was stable by 2 years and 5 months of age. Total SCFA levels reached those typical for adults by the age of 12. The structural index was most sensitive to integrated changes of the microbiome structure.Conclusion: Age-related characteristics of gut microbiome should be taken into account when performing clinical studies on effectiveness of therapeutic interventions and assessing the parameters in a given patient