Decreased serum SIRT6 as a novel predictor of coronary artery disease.

OBJECTIVE: SIRT6 is an NAD-dependent histone deacetylase known to regulate aging, inflammation and energy metabolism, and might play an important role in atherosclerosis. However, whether it also plays a role in coronary artery disease (CAD) remains unclear. PATIENTS AND METHODS: In this study, we detected the expression of SIRT6 in serum by Western blotting. The concentrations of SIRT6 in serum specimens from 69 patients with CAD [30 with stable angina (SA) and 39 with acute coronary syndrome (ACS)] and 16 controls were analysed using the enzyme-linked immunosorbent assay (ELISA) method. RESULTS: Western blotting analysis of the serum samples found that SIRT6 expression was decreased in the SA group (p=0.000) and ACS group (p=0.000) compared with the control group. Significantly lower levels of serum SIRT6 were observed in SA patients (18.80±9.14 ng/mL) and ACS patients (16.85±9.66 ng/mL) than in healthy controls (25.79±14.23 ng/mL). SIRT6 concentrations were positively correlated with other markers of CAD, such as high-density lipoprotein cholesterol (r=0.362, p<0.01) and age (r=0.265, p<0.05), and negatively correlated with blood glucose (r=-0.284, p<0.05). Multivariate logistic regression analysis demonstrated that lower SIRT6 levels were independently associated with the presence of CAD in men (OR=0.817, 95% CI 0.694-0.962, p=0.015). Receiver operating characteristic (ROC) curve analysis showed that lower serum SIRT6 could distinguish CAD patients (AUC, 0.726; 95% CI, 0.508-0.943; p=0.041) from controls. SIRT6 is found downregulated in blood vessels of atherosclerotic APOE-/- mice and human aorta arteries. CONCLUSIONS: We demonstrated that SA and ACS patients had lower serum concentrations of SIRT6. The decreased serum SIRT6 level was independently associated with the diagnosis of CAD. SIRT6 may play a cardioprotective role in CAD patients, and future research is required to address this issue.