Decreased serum SIRT6 as a novel predictor of coronary artery disease

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.

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.

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.

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.