The metabolic activity of gut microbiota in obese children is increased compared with normal-weight children and exhibits more exhaustive substrate utilization

Abstract

Objective:The gut microbiota contribute otherwise impossible metabolic functions to the human host. Shifts in the relative proportions of gut microbial communities in adults have been correlated with intestinal disease and have been associated with obesity. The aim of this study was to elucidate differences in gut microbial compositions and metabolite concentrations of obese versus normal-weight children.Materials and methods:Fecal samples were obtained from obese (n=15; mean body mass index (BMI) s.d. score=1.95) and normal-weight (n=15; BMI s.d. score=−0.14) Swiss children aged 8–14 years. Composition and diversity of gut microbiota were analyzed by qPCR and temperature gradient gel electrophoresis (TGGE).Results:No significant quantitative differences in gut microbiota communities of obese and normal-weight children were identified. Microbial community profiling by TGGE revealed a high degree of both intra- and intergroup variation. Intergroup comparison of TGGE profiles failed to identify any distinct populations exclusive to either obese or normal-weight children. High-pressure liquid chromatography analysis identified significantly higher (P<0.05) concentrations of short-chain fatty acids (SCFA) butyrate and propionate in obese versus normal-weight children. Significantly lower concentrations of intermediate metabolites were detected in obese children, suggesting exhaustive substrate utilization by obese gut microbiota.Conclusions:Our results indicate that a dysbiosis may be involved in the etiology of childhood obesity. In turn, aberrant and overactive metabolic activity within the intestine could dictate survival or loss of individual microbial communities, leading to the altered population ratios previously identified in adult obesity.

Pediatric obesity is associated with an altered gut microbiota and discordant shifts in Firmicutes populations

“…A recent meta-analysis concluded that there were no statistically significant differences across multiple studies in the Firmicutes/Bacteroidetes ratio between obese and normal-weight adults (Walters et al, 2014). In agreement with this meta-analysis, some pediatric studies have Ismail et al, 2011;Payne et al, 2011). Although in our study the Firmicutes/Bacteroidetes ratio was significantly elevated in obese individuals, we observed large variation in the ratio, particularly within the obese group.…”

Short-Chain Fatty Acids Regulate Secretion of IL-8 from Human Intestinal Epithelial Cell Linesin vitro

“…Later on, 20 mM of each SCFA or mixed SCFAs (similar to concentration in the colon) (Cummings et al, 1987;Kiefer et al, 2006;Treem et al, 1994) were used in the entire study. The mixture proportion of SCFAs was 3:1:1 ratio of acetate, propionate and butyrate, respectively (Payne et al, 2011;Hijova & Chmelarova, 2007). The cells then were incubated at 37 C in a humidified 5% CO 2 atmosphere for 72 h or until confluence.…”

Of the bugs that shape us: maternal obesity, the gut microbiome, and long-term disease risk

“…Finally, given the fact that gut microbiota both yield energy for their own growth and produce end products such as short chain fatty acids (SCFAs) for host metabolism (17) suggests that metabolomics are also required to understand the relationship between gut microbiome, obesity, and metabolic dysfunction. The metabolic activity of the gut microbiota is increased in obese children compared with lean children, thus gut dysbiosis is not limited to obesity in adulthood; it has also involved in the etiology of childhood obesity (18). As in the adult literature, there is evidence to suggest that not only are there shifts in fecal microbial populations in overweight children, but also variations in bacteria exist at the species levels (19).…”