The emerging role of lipidomics

Prognostic implication of lipidomics in patients with coronary total occlusion undergoing PCI

BACKGROUND

Predictors of prognosis in patients with coronary chronic total occlusion (CTO) undergoing elective percutaneous coronary intervention (PCI) have remained lacking. Lipidomic profiling enables researchers to associate lipid species with disease progression and may improve the prediction of cardiovascular events.

METHODS

In the present study, 781 lipids were measured by targeted lipidomic profiling in 350 individuals (50 healthy controls, 50 patients with coronary artery disease and 250 patients with CTO). L1-regularized logistic regression was used to identify lipid species associated with adverse cardiovascular events and create predicting models, which were verified by 10-fold cross-validation (200 repeats). Comparisons were made between a traditional model constructed with clinical characteristics alone and a combined model built with both lipidomic data and traditional factors.

RESULTS

Twenty-four lipid species were dysregulated exclusively in patients with CTO, most of which belonged to sphingomyelin (SM) and triacylglycerol (TAG). Compared with traditional risk factors, new model combining lipids and traditional factors had significantly improved performance in predicting adverse cardiovascular events in CTO patients after PCI (area under the curve, 0.870 vs. 0.726, p < .05; Akaike information criterion, 129 versus 156; net reclassification improvement, 0.312, p < .001; integrated discrimination improvement, 0.244, p < .001). Nomogram was built based on the incorporated model and proved efficient by Kaplan-Meier method.

CONCLUSIONS

Lipidomic profiling revealed lipid species which may participate in the formation of CTO and could contribute to the risk stratification in CTO patients undergoing PCI.

Association of Plasma Ceramides With Myocardial Perfusion in Patients With Coronary Artery Disease Undergoing Stress Myocardial Perfusion Scintigraphy

Objective- It is known that specific plasma ceramides are associated with stress-induced reversible myocardial perfusion defects in patients with established or suspected coronary artery disease undergoing myocardial perfusion scintigraphy (MPS). However, it is currently uncertain whether plasma ceramides are also associated with reduced poststress myocardial perfusion in these patients. Approach and Results- We measured 6 previously identified high-risk plasma ceramide species (ceramide [d18:1/16:0], ceramide [d18:1/18:0], ceramide [d18:1/20:0], ceramide [d18:1/22:0], ceramide [d18:1/24:0], and ceramide [d18:1/24:1]) in 167 consecutive patients with established or suspected coronary artery disease undergoing stress MPS for clinical indications. Plasma ceramides were measured by a targeted liquid chromatography-tandem mass spectrometry assay both at baseline and after MPS. Multivariable linear regression analysis was undertaken to examine the associations (standardized B coefficients) between plasma ceramides and the percentage of poststress myocardial perfusion after adjustment for multiple cardiovascular risk factors. Seventy-eight patients had stress-induced myocardial ischemia on MPS (mainly located in the anteroapical wall). Of the 6 measured plasma ceramides, higher levels of basal ceramide (d18:1/18:0; B=-0.182; P=0.019), ceramide (d18:1/20:0; B=-0.224; P=0.004), ceramide (d18:1/22:0; B=-0.163; P=0.035), and ceramide (d18:1/24:1; B=-0.20; P=0.010) were associated with lower poststress anteroapical wall perfusion. Notably, these significant associations persisted even after adjustment for conventional cardiovascular risk factors, previous coronary artery disease, electrocardiographic left bundle branch block, left ventricular ejection fraction and type of stress testing. Similar results were observed for poststress plasma ceramides. Conclusions- Higher circulating levels of specific ceramides, both at baseline and after stress, were independently associated with lower poststress anteroapical wall perfusion in patients with suspected or established coronary artery disease referred for clinically indicated MPS.

Plasma concentrations of molecular lipid species predict long-term clinical outcome in coronary artery disease patients

We investigated the associations of ten previously identified high risk molecular lipid species and three ceramide ratios with the occurrence of major adverse cardiac events (MACEs) during a median follow-up of 4.7 years in patients with coronary artery disease (CAD). Between 2008 and 2011, 581 patients underwent diagnostic coronary angiography or percutaneous coronary intervention for stable angina pectoris (SAP) or acute coronary syndrome (ACS). Blood was drawn prior to the index procedure and lipid species were determined. The primary endpoint was the occurrence of a MACE, comprising all-cause mortality, nonfatal ACS, or unplanned coronary revascularization. The secondary endpoint comprised all-cause mortality or nonfatal ACS. During a median follow-up of 4.7 [IQR: 4.2-5.6] years, 155 patients (27%) had MACEs. In multivariable analyses, Cer(d18:1/16:0) concentration was associated with MACEs {hazard ratio 2.32; 95% CI [1.09-4.96] per natural logarithm (ln) (pmol/ml) P = 0.030} after adjustment for cardiac risk factors, clinical presentation, statin use at baseline, and admission nonHDL cholesterol level. Furthermore, after multivariable adjustment, concentrations of Cer(d18:1/16:0), Cer(d18:1/20:0), Cer(d18:1/24:1), and their ratios to Cer(d18:1/24:0) were associated with the composite endpoint death or nonfatal ACS. The data together show the circulating ceramide lipids we investigated here are associated with adverse cardiac outcome during long-term follow-up independent of clinical risk factors.