Metabolites From Salivary Exosomes as Potential Biomarkers for Alveolar Bone and Tooth Resorption

Objective(s): In this pilot study, exosomes from saliva were isolated and tested for the presence of metabolomic biomarkers for physiological external root resorption and/or pathological alveolar bone resorption. Settings and Sample Population: Saliva samples of 20 individuals in the mixed dentition stage of dental development. Materials and Methods: Saliva was obtained from healthy control children with resorbing primary teeth or children with localised aggressive periodontitis (LAP) showing alveolar bone loss but little root resorption. Exosomes were isolated by differential centrifugation and analysed by electron microscopy, nanoparticle tracking analysis (NTA) and enzyme-linked immunosorbent assay (ELISA). Subsequently, exosomes were subjected to mass spectrometry to identify and quantitate metabolites. Differences between groups were statistically determined. Results: Over 2000 metabolites were detected in salivary exosomes. Metabolites that differed significantly between exosomes from the saliva of LAP patients and controls included L-pipecolic acid, acetylcholine, creatinine, N-acetylneuraminate and numerous unidentified molecules. Conclusion: This pilot study provided a proof-in-principle for using metabolites from salivary exosomes as biomarkers.