Saliva: Physiology and Diagnostic Potential in Health and Disease

Abstract

Saliva has been described as the mirror of the body. In a world of soaring healthcare costs and an environment where rapid diagnosis may be critical to a positive patient outcome, saliva is emerging as a viable alternative to blood sampling. In this review, we discuss the composition and various physiological roles of saliva in the oral cavity, including soft tissue protection, antimicrobial activities, and oral tissue repair. We then explore saliva as a diagnostic marker of local oral disease and focus particularly on oral cancers. The cancer theme continues when we focus on systemic disease diagnosis from salivary biomarkers. Communicable disease is the focus of the next section where we review the literature relating to the direct and indirect detection of pathogenic infections from human saliva. Finally, we discuss hormones involved in appetite regulation and whether saliva is a viable alternative to blood in order to monitor hormones that are involved in satiety.

Antimicrobial and anti-biofilm activities of Lactobacillus kefiranofaciens DD2 against oral pathogens

“…The survivability of the candidate strains was evaluated in a modified MRS medium containing α-amylase, which is a major oral digestive enzyme involved in the breakdown of polysaccharides that can reduce the survival of probiotic strains in the oral cavity by attacking bacterial polysaccharide components [26]. The commercial strains and those isolated from kefir were all highly resistant to α-amylase activity, which may be due to the action of capsular materials or protective polymeric substances surrounding the cell [18].…”

Application of Saliva as Diagnostic Bio-Fluid- An Overview

“…Another correlation has been found in increased levels of salivary lysozyme in hypertension, an early stage of CVD. [5,6] A number of salivary markers such as cortisol, nitrite, uric acid, sodium, chloride, pH, amylase etc have been associated with end stage renal disease. Salivary tests for biomarkers could be used to decide whether or not the dialysis is required thereby minimizing the visits to dialysis clinic.…”

“…Oral biomarkers like oncogenes (C-myc, c-Fos, C-Jun), antioncogenes (p53, p16), cytokines (transforming growth factor, interleukins, growth factors (vascular endothelial growth factor, epidermal growth factor), epithelial mesenchymal transition factors( E-cadherin, N-cadherin). [4,5] Recently certain salivary biomarkers such as tumor suppressor p53, carcinoma antigen CA15-3 and oncogene c-erB2 have found to be associated with non oral malignancies such as salivary gland adenomas and breast cancer subjects. Other salivary biomarker such as 4 mRNA is also used to differentiate pancreatic carcinoma subjects from pancreatitis and control subjects.…”

Ultrastructural and physico-chemical characterization of saliva during menstrual cycle in perspective of ovulation in human

“…Parotid glands and submandibular glands are contributing around 25% and 70%, whereas the sublingual glands account for only 5% of total salivary output (2,3). In recent years, more blood borne substances have been detected in saliva, which leads to saliva as an essential, noninvasive diagnostic medium.…”