Salivary Microbiota and Metabolome Associated with Celiac Disease

Abstract

e This study aimed to investigate the salivary microbiota and metabolome of 13 children with celiac disease (CD) under a glutenfree diet (treated celiac disease [T-CD]). The same number of healthy children (HC) was used as controls. The salivary microbiota was analyzed by an integrated approach using culture-dependent and -independent methods. Metabolome analysis was carried out by gas chromatography-mass spectrometry-solid-phase microextraction. Compared to HC, the number of some cultivable bacterial groups (e.g., total anaerobes) significantly (P < 0.05) differed in the saliva samples of the T-CD children. As shown by community-level catabolic profiles, the highest Shannon's diversity and substrate richness were found in HC. Pyrosequencing data showed the highest richness estimator and diversity index values for HC. Levels of Lachnospiraceae, Gemellaceae, and Streptococcus sanguinis were highest for the T-CD children. Streptococcus thermophilus levels were markedly decreased in T-CD children. The saliva of T-CD children showed the largest amount of Bacteroidetes (e.g., Porphyromonas sp., Porphyromonas endodontalis, and Prevotella nanceiensis), together with the smallest amount of Actinobacteria. T-CD children were also characterized by decreased levels of some Actinomyces species, Atopobium species, and Corynebacterium durum. Rothia mucilaginosa was the only Actinobacteria species found at the highest level in T-CD children. As shown by multivariate statistical analyses, the levels of organic volatile compounds markedly differentiated T-CD children. Some compounds (e.g., ethyl-acetate, nonanal, and 2-hexanone) were found to be associated with T-CD children. Correlations (false discovery rate [FDR], <0.05) were found between the relative abundances of bacteria and some volatile organic compounds (VOCs). The findings of this study indicated that CD is associated with oral dysbiosis that could affect the oral metabolome.

Salivary Gluten Degradation and Oral Microbial Profiles in Healthy Individuals and Celiac Disease Patients

“…Lactobacilli are natural colonizers of the oral cavity, with Lactobacillus rhamnosus being the most prevalent (26). While several studies have shown that the levels of Lactobacillus were lower in the duodenal and fecal samples in CD patients compared to healthy controls (31-33), reports on Lactobacillus levels in the oral cavity are inconsistent (34)(35)(36). Regardless of the microbial source, the modest increase in salivary enzyme activity is likely to be derived from bacteria given that dental plaque is a rich source of glutendegrading activity (21).…”

The Oral Microbiome of Children: Development, Disease, and Implications Beyond Oral Health

“…Likewise, children with celiac disease (1.4 years old in average) under gluten free diets show a less diverse salivary microbiome compared to healthy controls, and increased abundance of oral caries-related taxa (e.g. Rothia , Porphyromonas , Gemellaceae, Prevotella , Streptococcus and Lachnospiraceae) [111]. The abundances of these taxa also correlated with higher levels of organic volatile compounds in the saliva and fecal samples of affected children detected through GC-MS [112].…”

Does the microbiota play a role in the pathogenesis of autoimmune diseases?

“…There has been some interest in whether the oral microbiome differs in those with coeliac disease. Francavilla et al 96 showed that children treated for coeliac disease do have an altered oral microbiome, characterised by reduction in diversity and a change in abundance of various bacterial species. Specifically, there was an increase in Bacteroidetes and a reduction in Actinobacteria with representative changes in the oral metabolome.…”