Salivary Metaproteome as a Prediction Tool in Early Childhood Caries

Project summary

The term early childhood caries (ECC) describes the presence of one or more decayed, missing (due to caries) or filled primary teeth in children aged six years or younger. It has been shown that risk factors for ECC are frequent sugar consumption, inadequate oral hygiene as well as the colonization with cariogenic bacteria, such as the group of mutans streptococci, which are considered to be the main etiological agents of tooth decay in children. Other bacteria, such as Prevotella spp. and Lactobacillus spp., as well as fungus Candida albicans, were shown to be associated to the development and progression of ECC. Proteins in human saliva can influence the viability of oral microorganisms by various innate defense mechanisms, thus affect the composition of the oral microflora. Simultaneously bacteria are producing proteins to enhance various processes, e.g., the production of polysaccharides. While the word proteomics covers the exploration of all proteins from one species, metaproteomics relates to the investigation of proteins from microbial communities in interaction with the host, e.g. the host-microbiota crosstalk. Overall, the protein composition in young children's saliva, be it of microbial or human origin, could assist in biomarker implementation for early diagnosis as well as risk assessment of ECC.

This study aims to explore the overall salivary protein composition in cohorts of 3-year-old children from Swedish communities of varying risk for ECC, using high-throughput proteomics.

In brief, 50 3-year-old children will be recruited at two Public Dental Healthcare Centers, Folktandvården Danderyd and Folktandvården Järva, respectively. The project is structured in a clinical part (stage 1) and an analytical laboratory part (stage 2). Stage 1 will entail the recruitment of patients, the collection of saliva swab samples as well as the clinical examination, with particular emphasis on the presence of ECC. Stage 2 comprises the molecular analytical part during which the proteomic characterization of the saliva will take place. This molecular analytical part will be performed at the Department of Dental Medicine at Karolinska Institutet, with the support of the respective core facilities (Scaleless).

The investigators hypothesize that there are differential host proteomic and metaproteomic salivary profiles in ECC-affected children compared to caries-free children, and that these are associated with already identified risks for ECC posed between the two community-distinct cohorts.