Maša Primec^1,, Martina Klemenak², Irene Aloisio³, Mario Gorenjak^{4, 5}, Diana Di Gioia³, Dušanka Mičetić-Turk⁶, Tomaž Langerholc¹

Background: Knowledge about the interplay between diet, microbiota and short-chain fatty acids (SCFAs) so far exists. Moreover, raising evidence suggests their influence on the pathogenesis of the celiac disease (CD). Objective: Our aim was to study and evaluate differences in the composition of selected bacterial groups and SCFAs in faeces of healthy and CD children. Methods: The study included 41 children with CD, 8 newly discovered, not treated children (ND) and 33 children on gluten-free diet for more than 1 year (GFD) and 17 healthy children as a Control group. Bacterial communities and SCFAs in faecal samples were determined by real-time PCR and HPLC analysis, respectively. Results: There were no statistically significant differences between GFD and ND patients. GFD patients compared to Controls had significantly lower Lactobacillus spp. (p = 0.027) and Enterobacteriaceae family group (p = 0.003), but higher propionic acid (p = 0.034). Acetic (p = 0.027) and propionic acid (p = 0.014) were significantly higher in ND patients compared to Controls. Lactobacillus spp. negatively correlated with total SCFAs in the Control and the ND group. In ND and GFD patients, Lactobacillus spp. negatively correlated with Clostridium sensu stricto cluster I. A very strong positive correlation (p = 0.002) between Enterobacteriaceae family and Bacteroides fragilis was found in GFD patients. Conclusions: Changes in microbiota and SCFAs are clearly related to the pathogenesis of CD. As being potential pro-inflammatory agents in CD, acetic and propionic acid may serve as important disease-related markers. Their origin in relation to Lactobacillus and Bifidobacterium is debatable and still need to be further investigated. Enterobacteriaceae family might not be directly addressed to pathogenesis of CD.

celiac disease, children, gluten-free diet, microbiota, short-chain fatty acids