Plasma Ceramides as Prognostic Biomarkers and Their Arterial and Myocardial Tissue Correlates in Acute Myocardial Infarction

Ceramides and risk of major adverse cardiovascular events: A meta-analysis of longitudinal studies

BACKGROUND

Recent cohort studies evaluated the association between some previously identified high-risk ceramides [Cer(d18:1/16:0), Cer(d18:1/18:0), Cer(d18:1/22:0), Cer(d18:1/24:0) and Cer(d18:1/24:1)] and risk of major adverse cardiovascular events in adult population.

OBJECTIVE

The objective of this meta-analysis was to investigate the magnitude of such associations.

METHODS

We searched publication databases using appropriate keywords to identify cohort studies (published up to July 30, 2019), in which association between previously identified high-risk ceramides and major adverse cardiovascular events was reported. Data from eligible studies were extracted and meta-analysis was performed using random-effects modeling.

RESULTS

Seven cohort studies with aggregate data on 29,818 individuals (2736 new cases of cardiovascular events over a median follow-up of 6 years) were included. Higher plasma levels of Cer(d18:1/16:0) (random effects hazard ratio [HR] per standard deviation 1.21, 95% confidence interval [CI] 1.11-1.32, I² = 88%), Cer(d18:1/18:0) (HR 1.19, 95% CI 1.10-1.27, I² = 68%), and Cer(d18:1/24:1) (HR 1.17, 95% CI 1.08-1.27, I² = 83%) were associated with major adverse cardiovascular events. Conversely, no association with plasma levels of Cer(d18:1/22:0) (HR 1.14 95% CI 0.88-1.47, I² = 88%) and Cer(d18:1/24:0) (HR 0.97, 95% CI 0.89-1.05, I² = 73%) was found. Subgroup analyses did not substantially modify the findings.

CONCLUSIONS

Higher plasma levels of Cer(d18:1/16:0), Cer(d18:1/18:0) and Cer(d18:1/24:1) were associated with major adverse cardiovascular events, whereas plasma levels of Cer(d18:1/22:0) and Cer(d18:1/24:0) were not. Additional research is required to elucidate the different role of ceramides on pathways involved in cardiovascular disease.

Metabolomic profiling of dried blood spots reveals gender-specific discriminant models for the diagnosis of small cell lung cancer

The accurate diagnosis of small cell lung cancer (SCLC) at initial presentation is essential to ensure appropriate treatment. No validated blood biomarkers that could distinguish SCLC from non-small cell lung cancer (NSCLC) has yet been developed. Dried blood spot (DBS) microsampling has gained increasing interest in biomarkers discovery. In this study, we first performed metabolomic profiling of DBS samples from 37 SCLC, 40 NSCLC, and 37 controls. Two gender-specific multianalyte discriminant models were established for males and females, respectively to distinguish SCLC from NSCLC and controls. The receiver operator characteristic (ROC) curve analysis showed the diagnostic accuracy of 95% (95% CI: 83%-100%) in males SCLC using five metabolites in DBS and 94% (95% CI: 74%-100%) for females using another set of five metabolites. The robustness of the models was confirmed by the random permutation tests (P < 0.01 for both). The performance of the discriminant models was further evaluated using a validation cohort with 78 subjects. The developed discriminant models yielded an accuracy of 91% and 81% for males and females, respectively, in the validation cohort. Our results highlighted the potential clinical utility of the metabolomic profiling of DBS as a convenient and effective approach for the diagnosis of SCLC.

Dietary inulin decreases circulating ceramides by suppressing neutral sphingomyelinase expression and activity in mice

Elevated circulating levels of ceramides (Cers) are associated with increased risk of cardiometabolic diseases, and Cers may play a causative role in metabolic dysfunction that precedes cardiac events, such as mortality as a result of coronary artery disease. Although the mechanisms involved are likely complex, these associations suggest that lowering circulating Cer levels could be protective against cardiovascular diseases. Conversely, dietary fibers, such as inulin, have been reported to promote cardiovascular and metabolic health. However, the mechanisms involved in these protective processes also are not well understood. We studied the effects of inulin on lipid metabolism with a model of atherosclerosis in LDL receptor-deficient mice using lipidomics and transcriptomics. Plasma and tissues were collected at 10 days and/or 12 weeks after feeding mice an atherogenic diet supplemented with inulin or cellulose (control). Compared with controls, inulin-fed mice displayed a decreased C16:0/C24:0 plasma Cer ratio and lower levels of circulating Cers associated with VLDL and LDL. Liver transcriptomic analysis revealed that Smpd3, a gene that encodes neutral SMase (NSMase), was downregulated by 2-fold in inulin-fed mice. Hepatic NSMase activity was 3-fold lower in inulin-fed mice than in controls. Furthermore, liver redox status and compositions of phosphatidylserine and FFA species, the major factors that determine NSMase activity, were also modified by inulin. Taken together, these results showed that, in mice, inulin can decrease plasma Cer levels through reductions in NSMase expression and activity, suggesting a mechanism by which fiber could reduce cardiometabolic disease risk.

Hurdles to Cardioprotection in the Critically Ill

Cardiovascular disease is the largest contributor to worldwide mortality, and the deleterious impact of heart failure (HF) is projected to grow exponentially in the future. As heart transplantation (HTx) is the only effective treatment for end-stage HF, development of mechanical circulatory support (MCS) technology has unveiled additional therapeutic options for refractory cardiac disease. Unfortunately, despite both MCS and HTx being quintessential treatments for significant cardiac impairment, associated morbidity and mortality remain high. MCS technology continues to evolve, but is associated with numerous disturbances to cardiac function (e.g., oxidative damage, arrhythmias). Following MCS intervention, HTx is frequently the destination option for survival of critically ill cardiac patients. While effective, donor hearts are scarce, thus limiting HTx to few qualifying patients, and HTx remains correlated with substantial post-HTx complications. While MCS and HTx are vital to survival of critically ill cardiac patients, cardioprotective strategies to improve outcomes from these treatments are highly desirable. Accordingly, this review summarizes the current status of MCS and HTx in the clinic, and the associated cardiac complications inherent to these treatments. Furthermore, we detail current research being undertaken to improve cardiac outcomes following MCS/HTx, and important considerations for reducing the significant morbidity and mortality associated with these necessary treatment strategies.

Effect of combined testing of ceramides with high-sensitive troponin T on the detection of acute coronary syndrome in patients with chest pain in China: a prospective observational study

OBJECTIVE

Ceramides are associated with coronary plaque vulnerability. We aim to investigate the potential diagnostic value of ceramides for acute coronary syndrome (ACS) in Chinese patients with chest pain.

DESIGN

Prospective observational survey.

SETTING

Shanghai, China, 2016-2017.

PARTICIPANTS

A total of 2773 patients with chest pain from four hospitals in Shanghai, China, between August 2016 and October 2017.

MAIN OUTCOME MEASURES

Performance of metabolites model in detection of ACS cases including ST-elevation myocardial infarction (STEMI), non-STEMI (NSTEMI) and unstable angina.

RESULTS

Plasma levels of 12 ceramide molecules and corresponding ratios were compared between patients diagnosed with ACS and those without. Cer(d18:1/24:1(15Z))/Cer(d18:1/24:0) ratio, Cer(d18:1/14:0) and Cer(d18:1/22:0) were independent predictors of ACS after adjustment of traditional risk factors and high-sensitivecardiac troponin T. Receiver operating characteristic curve analysis showed a significant improvement in detecting ACS in the multivariable model with ceramides compared with that without (0.865 (0.840 to 0.889) vs 0.808 (0.776 to 0.841), p<0.001).

CONCLUSION

Distinct plasma ceramides are independent diagnostic predictors of ACS among patients with chest pain. Ceramides together with high-sensitive troponin and traditional factors showed great potential in identifying ACS among patients with chest pain.

Extracellular Vesicles in Cardiovascular Diseases: Alternative Biomarker Sources, Therapeutic Agents, and Drug Delivery Carriers

Cardiovascular diseases (CVD) represent the leading cause of morbidity and mortality globally. The emerging role of extracellular vesicles (EVs) in intercellular communication has stimulated renewed interest in exploring the potential application of EVs as tools for diagnosis, prognosis, and therapy in CVD. The ubiquitous nature of EVs in biological fluids presents a technological advantage compared to current diagnostic tools by virtue of their notable stability. EV contents, such as proteins and microRNAs, represent specific signatures of cellular activation or injury. This feature positions EVs as an alternative source of biomarkers. Furthermore, their intrinsic activity and immunomodulatory properties offer EVs unique opportunities to act as therapeutic agents per se or to serve as drug delivery carriers by acting as miniaturized vehicles incorporating bioactive molecules. In this article, we aim to review the recent advances and applications of EV-based biomarkers and therapeutics. In addition, the potential of EVs as a drug delivery and theranostic platform for CVD will also be discussed.

7TM proteins are not necessarily GPCRs

In this review article, we summarize the current knowledge on a large and diverse superfamily of seven-pass transmembrane proteins functionally independent from the GPCR superfamily. We include the newest research findings about their physiological roles and their mechanism of action. In particular, we concentrate on the structural basis for the newly discovered amide hydrolase activity, with a focus on adiponectin receptors for which structures are available. Finally, we discuss the remaining challenges in understanding the activation and signaling of these intramembrane proteins and suggest how regulation of the amide hydrolase activity may help in development of new therapeutic agents.

Metabolic modulation predicts heart failure tests performance

The metabolic changes that accompany changes in Cardiopulmonary testing (CPET) and heart failure biomarkers (HFbio) are not well known. We undertook metabolomic and lipidomic phenotyping of a cohort of heart failure (HF) patients and utilized Multiple Regression Analysis (MRA) to identify associations to CPET and HFBio test performance (peak oxygen consumption (Peak VO₂), oxygen uptake efficiency slope (OUES), exercise duration, and minute ventilation-carbon dioxide production slope (VE/VCO₂ slope), as well as the established HF biomarkers of inflammation C-reactive protein (CRP), beta-galactoside-binding protein (galectin-3), and N-terminal prohormone of brain natriuretic peptide (NT-proBNP)). A cohort of 49 patients with a left ventricular ejection fraction < 50%, predominantly males African American, presenting a high frequency of diabetes, hyperlipidemia, and hypertension were used in the study. MRA revealed that metabolic models for VE/VCO₂ and Peak VO₂ were the most fitted models, and the highest predictors’ coefficients were from Acylcarnitine C18:2, palmitic acid, citric acid, asparagine, and 3-hydroxybutiric acid. Metabolic Pathway Analysis (MetPA) used predictors to identify the most relevant metabolic pathways associated to the study, aminoacyl-tRNA and amino acid biosynthesis, amino acid metabolism, nitrogen metabolism, pantothenate and CoA biosynthesis, sphingolipid and glycerolipid metabolism, fatty acid biosynthesis, glutathione metabolism, and pentose phosphate pathway (PPP). Metabolite Set Enrichment Analysis (MSEA) found associations of our findings with pre-existing biological knowledge from studies of human plasma metabolism as brain dysfunction and enzyme deficiencies associated with lactic acidosis. Our results indicate a profile of oxidative stress, lactic acidosis, and metabolic syndrome coupled with mitochondria dysfunction in patients with HF tests poor performance. The insights resulting from this study coincides with what has previously been discussed in existing literature thereby supporting the validity of our findings while at the same time characterizing the metabolic underpinning of CPET and HFBio.

Ceramide and Regulation of Vascular Tone

In addition to playing a role as a structural component of cellular membranes, ceramide is now clearly recognized as a bioactive lipid implicated in a variety of physiological functions. This review aims to provide updated information on the role of ceramide in the regulation of vascular tone. Ceramide may induce vasodilator or vasoconstrictor effects by interacting with several signaling pathways in endothelial and smooth muscle cells. There is a clear, albeit complex, interaction between ceramide and redox signaling. In fact, reactive oxygen species (ROS) activate different ceramide generating pathways and, conversely, ceramide is known to increase ROS production. In recent years, ceramide has emerged as a novel key player in oxygen sensing in vascular cells and mediating vascular responses of crucial physiological relevance such as hypoxic pulmonary vasoconstriction (HPV) or normoxic ductus arteriosus constriction. Likewise, a growing body of evidence over the last years suggests that exaggerated production of vascular ceramide may have detrimental effects in a number of pathological processes including cardiovascular and lung diseases.