Salivary biomarkers – A review

The value of salivary biomarkers for diagnostic and prognostic assessments has become increasingly well established in medicine, pharmacology, and dentistry. Certain salivary components mirror the neuro – endocrine status of the organism. Other saliva products are protein in nature, and can serve to reflect immune surveillance processes. The autonomic nervous system regulates the process of salivation, and the concentration of yet other salivary components, such as α-amylase, which provide a reliable outcome measure of the sympathetic response. A wide range of biomarkers is measurable in saliva, including heavy metals (eg, lead), hormones (eg, cortisol, dehydroxyepiandrosterone (DHEA)), toxins and their metabolites (eg, cotinine), enzymes (eg, lysozyme, a-amylase), immunoglobulins (eg, IgA), other proteins (eg, eosinophil cationic protein) and DNA. Researchers are also studying the proteomic components of saliva in the hope of identifying novel biomarkers of disease. There have been significant advances in techniques for the detection of biomarker signals in the oral cavity (e.g., ELISAs for proteins, PCR for RNA and DNA) as well as the engineering and development of micro fluidic approaches to make oral-based point-of-care (POC) methods for the diagnosis for both local and systemic conditions a reality. In this section, we focus on three such approaches, namely, periodontal disease management, early markers for systemic diseases, and salivary markers useful for pharmacogenomic studies. Novel approaches using noninvasive, salivary samples and user-friendly devices offer results that are as sensitive and specific as laboratory-based analyses using blood or urine