Detection of Homocysteine and C-Reactive Protein in the Saliva of Healthy Adults: Comparison with Blood Levels

Abstract

Inflammation and cardiovascular disease are associated with elevated serum levels of C-Reactive Protein (CRP) and homocysteine. The presence of both molecules in saliva provides an opportunity for development of non-invasive assessments of disease risk. However, salivary CRP and homocysteine reference ranges and their correlation with serum levels are unknown. This study investigated if CRP and homocysteine could be routinely detected in the saliva of healthy adults and the relationship between salivary and blood levels. CRP and homocysteine concentrations were determined using ELISA and enzymatic assays respectively. Homocysteine was detected in only two saliva samples (n = 55). CRP was measurable in all saliva samples (range: 0.05 to 64.3 μg/L; median = 1.2 μg/L) and plasma samples (range: 0.14 to 31.1 mg/L; median = 2.0 mg/L). Regression analysis demonstrated no relationship between CRP concentration in saliva and plasma (R2 = 0.001). Generalized linear models including variables such as saliva flow rate and time since eating or drinking also did not pass lack of fit testing. Therefore, a relationship between CRP concentration in saliva and blood could not be established in this group of subjects. More sensitive detection methods are needed to determine if a correlation between salivary and serum homocysteine levels exists.

Salivary Acute Phase Proteins as Biomarker in Oral and Systemic Disease

“…A local synthesis in oral cavity of transferrin, alpha 1-acid glycoprotein, alpha 1-antitrypsin and haptoglobin was observed in infants (Szabo, 1988). Increased CRP mRNA expression in the submandibular glands of rats with experimentally induced inflammation was recently reported (Dillon, 2010). It is now widely accepted that acute phase protein synthesis may take place in extra-hepatic cell types.…”

Metabolomics in the Context of Forensic Omics Biomarkers

“…The presence of C-reactive protein (CRP) molecules in saliva provides an opportunity for development of non-invasive assessments of cardiovascular diseases risk factors [67]. The use of this simple no invasive sample requires the establishment of salivary CRP reference ranges and their correlation with serum concentrations, which have not been investigated in detail yet.…”

The Effects of Phase III Cardiac Rehabilitation in Serum and Salivary Hs-CRP and Anthropometric Measurements in Patients with Coronary Artery Disease

“…7 Salivary CRP levels have been used to assess whether CRP determination in saliva samples could be utilized as a way to detect inflammation, and as an alternative approach to evaluate disease risk and monitoring the response to treatment. 8 Previous studies demonstrated that the plasma levels of hs-CRP are significantly decreased after exercise training program, 3,[9][10][11][12] suggesting that rehabilitation program may develop an anti-inflammatory reaction. However, reports showing the levels of hs-CRP in saliva before, during and after cardiac rehabilitation are lacking.…”

“…Some of them are produced in the salivary glands. 8 Since, a strong correlation between serum and nonstimulated salivary hs-CRP concentrations was observed before and after intervention, serum origin of hs-CRP is accepted. The association between serum concentrations of hs-CRP and stimulated saliva was not statistically significant.…”

“…Some studies have reported that periodontal disease is associated with increased salivary and also serum CRP levels. 8 We had not a control group because of ethical constraints.…”