Differential Expression Proteomics of Saliva From Children With Caries at Different Stages of Severity

Objectives: Biomarkers for dental caries can be identified among salivary proteins, since saliva is an easy-to-obtain biological fluid and is essential for protecting the dentition. The present study performed a comparative analysis of proteins from the saliva of patients with early childhood caries (ECC) at different levels of severity, in order to identify potential specific salivary biomarkers for caries diagnosis.
Methods: For the study, 126 children (2-6 years old) were selected. Initially, the children were examined according to the visual index ICDAS II and divided into 3 groups (n = 42): Caries-free group (CF) (ICDAS 0), Enamel caries group (EC) (ICDAS 1, 2 and 3) and Dentine caries group (DC) (ICDAS 5 and 6). Then, the saliva was collected, processed and stored. The samples were digested and analyzed for mass spectrometry alternative multiplexed scanning (MSE). Analyses were performed with TransOmics Software and ANOVA and Volcano plot v-plot (p<0.05).
Results: Three hundred one proteins were identified and quantified, among them, 122 proteins were statistically significant different at least in one group: 84 were identified in all 3 groups; one protein was expressed only in CF and other in EC; 11 were expressed only in CF and EC, 15 in CF and DC, 10 in EC and DC. Of the 122 proteins, 54 proteins were at least 5 times more expressed in the comparison between the groups and were considered as candidates for biomarkers. From these 54, 18 proteins with potential mechanism of action related to dental caries were selected and analyzed.
Conclusions: Concluding, these 18 proteins presented correlation with ECC, and SAA1, AIMP1, IL36A, and IL36G CAH1 may have increased potential to be considered as caries biomarkers. However, longitudinal studies still need to be made in order to establish the role of the proteins studied and to consolidate its role as a biomarker.