Saliva Diagnostics: Utilizing Oral Fluids to Determine Health Status

Abstract

Imagine a time where your health status could be available to you without the pain, discomfort and inconvenience of a physical examination. Distant vision of an inconceivable future or impending reality with potentially immeasurable impact? Recent advancements in the field of molecular diagnostics indicate this is not only possible, but closer than we think. Novel discoveries and substantial advancements have revealed that saliva may contain real-time information describing our overall physiological condition. Researchers are now reporting that, like blood and tissue biopsies, oral fluids could be a source of biochemical data capable of detecting certain diseases. What is even more intriguing is that this phenomenon not only applies to local disorders like oral cancer and Sjögren's syndrome, but distant pathologies like autoimmune, cardiovascular and metabolic diseases as well as viral/bacterial infections and even some cancers. These revelations have provided a foundation for the burgeoning field of salivary diagnostics and hence spurred the onset of investigations poised at deciphering the salivary milieu. This paper overviews salivary diagnostics from biomarker development to the multitude of techniques utilized in identifying saliva-based molecular indicators of disease. In doing so, we present oral fluids as an easily accessible noninvasive alternative to traditional diagnostic avenues and not just an essential component of the digestive process. Determining saliva as a credible means of evaluating health status represents a considerable leap forward in health care, one that could lead to enormous translational advantages and significant clinical opportunities.

18S and GAPDH housekeeping genes seem to be equally useful in saliva

“…We agree with Schafer CA et al, in that saliva offers a considerable leap forward in (Schafer et al, 2014), but as a first approach, it has to be clarified the best housekeeping genes for this corporal fluid to be used in qPCR.…”

Characterization of saliva microbiota’s functional feature based on metagenomic sequencing

“…However, for saliva microbiota, there’s only one report on a single sample from a healthy individual (Lazarevic et al 2012), yet what they focused is the bacterial profile, instead of functional feature. In this study, we choose unstimulated saliva as the origin of saliva samples, to avoid the potential that procedure of stimulated saliva sample collective may dilute or lead to quantity difference of the saliva microbiota (Schafer et al 2014; Yakob et al 2014; Belstrom et al 2016). Here we report the first metagenomic analysis of saliva using WGS sequencing to experimentally reconstruct the global genomic profile of saliva from two healthy (“H”) and two caries-active (DMFT ≧ 6) (“C”) adults.…”

Oral Biofluid Biomarker Research: Current Status and Emerging Frontiers

“…Because each of the salivary glands is encapsulated by capillaries, each gland is allowed free exchange of blood-based molecules into the adjacent saliva-producing acinus cells. Previous research has suggested that circulating biomolecules that originate from a diseased process from the bloodstream may eventually be transported into the salivary glands, which will then consequently modify and change the composition of saliva [3,4,5]. Hence, it is of recent interest to locate saliva-based targets to evaluate an individual’s current state of health, as saliva is functionally equivalent to blood plasma or serum in diagnostic medicine.…”

“…Currently, scientists have shown that these salivary constituents are effective indicators of many disorders. Multiple proteomic, transcriptomic, and microbiological markers have been identified for various pathologies: some prominent studies have been oral cancer, breast cancer, lung cancer, pancreatic cancer, and Sjögren’s syndrome [3,4,5,6]. …”