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Aims: The aim was to study the prognostic value of plasma ceramides (Cer) as cardiovascular death (CV death) markers in three independent coronary artery disease (CAD) cohorts., Methods and Results: Corogene study is a prospective Finnish cohort including stable CAD patients (n = 160). Multiple lipid biomarkers and C-reactive protein were measured in addition to plasma Cer(d18:1/16:0), Cer(d18:1/18:0), Cer(d18:1/24:0), and Cer(d18:1/24:1). Subsequently, the association between high-risk ceramides and CV mortality was investigated in the prospective Special Program University Medicine-Inflammation in Acute Coronary Syndromes (SPUM-ACS) cohort (n = 1637), conducted in four Swiss university hospitals. Finally, the results were validated in Bergen Coronary Angiography Cohort (BECAC), a prospective Norwegian cohort study of stable CAD patients. Ceramides, especially when used in ratios, were significantly associated with CV death in all studies, independent of other lipid markers and C-reactive protein. Adjusted odds ratios per standard deviation for the Cer(d18:1/16:0)/Cer(d18:1/24:0) ratio were 4.49 (95% CI, 2.24-8.98), 1.64 (1.29-2.08), and 1.77 (1.41-2.23) in the Corogene, SPUM-ACS, and BECAC studies, respectively. The Cer(d18:1/16:0)/Cer(d18:1/24:0) ratio improved the predictive value of the GRACE score (net reclassification improvement, NRI = 0.17 and ΔAUC = 0.09) in ACS and the predictive value of the Marschner score in stable CAD (NRI = 0.15 and ΔAUC = 0.02)., Conclusions: Distinct plasma ceramide ratios are significant predictors of CV death both in patients with stable CAD and ACS, over and above currently used lipid markers. This may improve the identification of high-risk patients in need of more aggressive therapeutic interventions., (© The Author 2016. Published by Oxford University Press on behalf of the European Society of Cardiology.)

The impact of cigarette smoke (CS), a major cause of lung diseases, on the composition and metabolism of lung lipids is incompletely understood. Here, we integrated quantitative lipidomics and proteomics to investigate exposure effects on lung lipid metabolism in a C57BL/6 and an Apolipoprotein E-deficient (Apoe(-/-)) mouse study. In these studies, mice were exposed to high concentrations of 3R4F reference CS, aerosol from potential modified risk tobacco products (MRTPs) or filtered air (Sham) for up to 8 months. The 2 assessed MRTPs, the prototypical MRTP for C57BL/6 mice and the Tobacco Heating System 2.2 for Apoe(-/-) mice, utilize "heat-not-burn" technologies and were each matched in nicotine concentrations to the 3R4F CS. After 2 months of CS exposure, some groups were either switched to the MRTP or underwent cessation. In both mouse strains, CS strongly affected several categories of lung lipids and lipid-related proteins. Candidate surfactant lipids, surfactant proteins, and surfactant metabolizing proteins were increased. Inflammatory eicosanoids, their metabolic enzymes, and several ceramide classes were elevated. Overall, CS induced a coordinated lipid response controlled by transcription regulators such as SREBP proteins and supported by other metabolic adaptations. In contrast, most of these changes were absent in the mice exposed to the potential MRTPs, in the cessation group, and the switching group. Our findings demonstrate the complex biological response of the lungs to CS exposure and support the benefits of cessation or switching to a heat-not-burn product using a design such as those employed in this study., (© The Author 2015. Published by Oxford University Press on behalf of the Society of Toxicology.)

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.

Context: Animal studies revealed that medium-chain fatty acids (MCFA), due to their metabolic characteristics, are not stored in skeletal muscle and may therefore not give rise to potentially hazardous lipid species impeding insulin signaling., Objective: We here hypothesized that infusion of medium-chain triacylglycerols (MCT) in healthy lean subjects does not lead to ectopic fat accumulation and hence does not result in lipid-induced insulin resistance., Design and Methods: Nine healthy lean male subjects underwent a 6-h hyperinsulinemic-euglycemic clamp with simultaneous infusion of 1) a 100% long-chain triacylglycerols (LCT) emulsion, 2) a 50/50% MCT/LCT emulsion, or 3) glycerol in a randomized crossover design. Muscle biopsies were taken before and after each clamp., Results: MCT/LCT infusion raised plasma free fatty acid levels to a similar level compared with LCT infusion alone. Despite elevated free fatty acid levels, intramyocellular triacylglycerol (IMTG) levels were not affected by the MCT/LCT emulsion, whereas LCT infusion resulted in an approximately 1.6-fold increase in IMTG. These differences in muscle fat accumulation did not result in significant differences in lipid-induced insulin resistance between LCT (-28%, P = 0.003) and MCT/LCT (-20%, P < 0.001). Total skeletal muscle ceramide content as well as lactosyl- and glucosylceramide levels were not affected by any of the interventions. In addition, the distribution pattern of all ceramide species remained unaltered., Conclusions: Although we confirm that MCFA do not lead to ceramide and IMTG accumulation in skeletal muscle tissue in humans, they do induce insulin resistance. These results indicate that, in humans, MCFA may not be beneficial in preventing peripheral insulin resistance.