Molecular lipids identify cardiovascular risk and are efficiently lowered by simvastatin and PCSK9 deficiency

Abstract

Context: Coronary artery disease (CAD) is among the leading causes of mortality and morbidity worldwide. Traditional risk markers explain only a proportion of total cardiovascular risk. Thus, development and improvement of early diagnostic strategies and targeted initiation of preventive measures would be of great benefit.

Objective: We aimed to identify molecular lipids that are associated with fatal outcome of CAD patients. Furthermore, the effect of different lipid-lowering drugs on novel risk lipids was evaluated.

Methods: Serum samples of 445 CAD subjects participating in a long-term follow-up of the Ludwigshafen Risk and Cardiovascular Health (LURIC) study were analyzed. In addition, samples obtained from a separate randomized parallel three-group study of subjects treated with simvastatin (n=24), ezetimibe (n=24), or their combination (n=24) were studied. Furthermore, samples from the LURIC participants with a loss-of-function mutation (R46L) in the PCSK9 gene (n=19) were analyzed and compared with major allele carriers (n=868).

Results: Distinct ceramide species were significantly associated with the fatal outcome of CAD patients. Simvastatin lowered plasma ceramides broadly by about 25%, but no changes in ceramides were observed in the ezetimibe group. PCSK9 deficiency was significantly associated (-13%) with lowered low-density lipoprotein cholesterol accompanied by a significant 20% reduction in CAD outcome risk-related ceramides.

Conclusions: These data suggest that distinct ceramides associate significantly with CAD outcome independently of traditional risk factors and that the mechanism of lipid lowering is important.

Figure 1.

Volcano heat map indicating molecular lipid species difference (percentage) between stable and high-risk CAD patients. Right panel (red color) indicates lipids that associate with CVD outcome risk in CAD patients. Left panel (blue color) indicates lipids that associate with protection. Lipid concentrations in controls are taken as a reference; thus, positive values correspond to higher values in cases vs controls.

Figure 2.

Differential behavior of sphingolipid species in sphingolipid pathway. A, Sphingolipid pathway map. B, Heat map of sphingolipid differences.

Figure 3.

Volcano heat map indicating molecular lipids and ceramide to ceramide ratio differences between all studied stable CAD patients and high-risk CAD patients (A), differences between stable CAD patients and vulnerable CAD patients with diabetes (B), and patients without diabetes (C). Lipid concentrations in controls are taken as a reference; thus, positive values correspond to higher values in cases vs controls.

Figure 4.

The effect of different LDL-C-lowering methods on CAD outcome-related lipidomic markers. A, Lipid profile in high-risk vs stable CAD patients. Results shown for top ranked CAD risk lipids, LDL-C, and ceramide (18:1/24:0). Effect of ezetimibe (10 mg) (B), simvastatin (40 mg) (C), simvastatin + ezetimibe (40 mg+10 mg), (D) and PCSK9 loss-of-function mutation (R46L) (E) on CAD mortality risk lipids.