Gut microbiota in GSD type Ia and Ib patients

A life-long dietary intervention can affect the substrates availability for gut microbial fermentation in metabolic diseases such as the glycogen-storage diseases (GSD). Besides drug consumption, the main treatment of types GSD-Ia and -Ib to prevent metabolic complications is a peculiar diet with specific nutrient intakes. In order to evaluate how deeply this dietary treatment affects gut bacteria, we compared the gut microbiota composition of 9 GSD-I subjects and 12 healthy controls (HC) through 16S rRNA gene sequencing; we assessed their dietary intake and nutrients, their microbial short chain fatty acids (SCFAs) via gas chromatography and the hematic values of patients. Both alpha-diversity and phylogenetic analysis revealed a significant biodiversity reduction in the GSD group compared to the HC group, and highlighted profound differences of their gut microbiota. GSD subjects were characterized by an increase in the relative abundance of Enterobacteriaceae and Veillonellaceae families, while the beneficial genera Faecalibacterium and Oscillospira were significantly reduced. SCFAs quantification revealed a significant increase of fecal acetate and propionate in GSD subjects, but with a beneficial role probably reduced due to unbalanced bacterial interactions; nutritional values correlated to bacterial genera were profoundly different between experimental groups, with nearly opposite cohort trends.