Sialochemistry; A Diagnostic Tool
however, saliva has many advantages over both serum and urine. For example, salivary assays for anti-bodies (to viruses and bacteria), unconjugated steroid hormones (e.g. estrogen, testosterone and progesterone), environmental toxins (e.g., cadmium, lead and mercury), tobacco (cotinine) and certain drugs (ethanol, theophylline and lithium) are sufficiently sensitive to accurately reflect the blood concentrations of these substances22.
Methods for determining salivary gland dysfunction include salivary flow rate measurements (sialometry) and analysis of salivary composition (sialochemistry) analysed by using radioimmunoassay (RIA), for which whole saliva (oral fluid) is most frequently used. The concentration of IgA was somewhat elevated (commensurate with reduced flow rate); the levels of IgG, IgM, and albumin were normal. The major functional abnormality of the parotid gland in Sjögren’s syndrome appears to be luminal transport in the ductal region; leakage of serum components is minimal. Sialochemistry can be helpful in differentiating Sjögren’s disease from other diseases of the salivary
gland and in assessing degree of pathologic change.23
p53 antibody is a tumor suppressor protein which is produced in cells exposed to various types of DNA-damaging stress, can also be detected in the saliva of patients diagnosed with oral squamous cell carcinoma (SCC), and can thus assist in the early
detection and screening for this tumor. Higher concentrations of salivary defensin-1 were detected in patients with oral SCC in comparison to healthy controls. 24
The activity of CK (creatinine kinase), LDH, ACP (acidic phosphatase), GGT (gamma glutamyl transferase) in saliva from patients with periodontal disease, before & after treatment (experimental Group 30 samples), & in saliva from periodontally healthy patients (20 samples) were studied. The results showed the elevated levels of these enzymes before the treatment in periodontal patients when compared with healthy patients.25
Study conducted in 273 workers, who were divided into non passive & active smokers based on salivary cotinine levels on 0, 1-7 & >8 mg/ml respectively. Levels of salivary markers, including IL-1b, lactoferrin, albumin were elevated in passive smokers compared to non smokers, were independently associated with cotinine level. They concluded that passive smoke exposure leads to elevation of IL-1b, albumin and aspartate aminotransferase (AST) levels in saliva.26
Patients with heart diseases were divided into 2 groups: Warfarin user & Warfarin non-user, and six components of saliva: salivary total protein (TP), albumin(ALB), C-reactive protein (CRP), aspartate aminotransferase (AST), alanine aminotransferase (ALT), creatine kinase (CK) were determined to assess intra oral pathologic conditions. As a result there were many cases showing a high ALB, CRP, AST and ALT level in Warfarin user and significant correlation found between clinical parameters and salivary components.12
Increased levels of circulating and salivary cortisol (the stress hormone) result from the activation of the hypothalamic–pituitary–adrenal axis brought on by psychological stress and extensive physical activity. Salivary proteins can also maintain an ecological balance among the diverse bacteria that affect oral and general health. Recent studies have shown that several species of oral streptococci, such as Streptococcus gordonii, bind to salivary alpha-amylase immobilized onto hydroxyapatite surfaces. Thus amylase, as a receptor for streptococcal adhesion to the tooth, contributes to the formation of dental plaque.16
Significant decrease of sodium in sialadenosis, and increase of sodium and total protein in sialadenitis have been found.27Typical respiratory pathogens, such as Streptococcus pneumoniae, Streptococcus pyogenes, Mycoplasma pneumoniae and Haemophilus influenzae, colonize the dental plaque of intensive care patients and residents of nursing homes. Once established in the mouth, these pathogens can be aspirated into the lung and cause a nosocomial infection. saliva samples were tested for the presence of H. pyloriDNA by polymerase chain-reaction (PCR) assay, and sensitivity of 84%was reported. Atkinson found that the saliva of HIV-positive patients contained increased levels of histatins and increased levels of lactoferrin.28 Several salivary and oral fluid tests have been developed for HIV diagnosis. Orasure® is a testing system that is commercially available in the United States and can be used for the diagnosis of HIV. The test relies on the collection of an oral mucosal transudate (and therefore IgG antibody). IgG antibody to the virus is the predominant type of anti-HIV immunoglobulin. ELISA may offer a valuable complement to conventional diagnostic methods for pneumococcal pneumonia. Detection of this antigen in saliva demonstrated a sensitivity of 55% and specificity