Cardiac Biomarkers in Oral Fluids of Acute Coronary Syndrome

Biodiagnostics continue to be a burgeoning field of healthcare, with increasingly sophisticated technologies providing biologic measures for risk of cancer, neurodegenerative diseases, cardiovascular disease, and others. Most of these technologies have focused on serum/plasma as a diagnostic fluid, recent data have suggested that saliva may provide some unique opportunities as a non-invasive fluid for these measures. Objective: This study examined the detection of a panel of cardiac biomarkers in oral fluids and evaluated differences in levels between acute coronary syndrome (ACS) patients and control subjects. Methods: Unstimulated (UWS) and stimulated (SWS) whole saliva were obtained from a group of control subjects (n=29) and patients hospitalized with a ST-elevated myocardial infarction (STEMI) or non-STEMI (NSTEMI) cardiac event (n=30). From 8 to 48 hours after diagnosis of the myocardial infarction (MI), patients were consented and saliva and serum collected. Levels of brain-natriuretic peptide (BNP), troponin I, (TpnI), creatine kinase-MB (CK-MB), and myoglobin (MYO) were determined in the fluids. Results: BNP, TpnI, CK-MB and MYO were all detectable in both types of saliva specimens. Of the four cardiac enzymes, MYO was detected significantly more often in UWS (p<0.001) and SWS (p<0.02) and at higher levels than controls. BNP was detected in 68% to 82% of MI salivas in UWS and SWS. In contrast, CK-MB was consistently detected in the majority of STEMI and NSTEMI SWS. Salivary TpnI levels were highest in the STEMI group, in UWS, and at early time points post-MI. As was predicted, all of these biomarkers were significantly elevated in serum of ACS patients. Conclusions: The findings suggest that salivary samples could be used to detect a standard battery of cardiac biomarkers obtained from patients with ACS. Moreover, this panel of analytes may be a useful tool in risk assessment for ACS. Supported by U01 DE017793 from the NIDCR.