Ceramides improve atherosclerotic cardiovascular disease risk assessment beyond standard risk factors

Obesity and dyslipidemia in early life: Impact on cardiometabolic risk

Childhood obesity with its growing prevalence worldwide presents one of the most important health challenges nowadays. Multiple mechanisms are involved in the development of this condition, as well as in its associations with various cardiometabolic complications, such as insulin resistance, diabetes, metabolic dysfunction-associated steatotic liver disease and cardiovascular diseases. Recent findings suggest that childhood obesity and associated dyslipidemia at least partly originate from epigenetic modifications that take place in the earliest periods of life, namely prenatal and perinatal periods. Hence, alterations of maternal metabolism could be fundamentally responsible for fetal and neonatal metabolic programming and consequently, for metabolic health of offspring in later life. In this paper, we will review recent findings on the associations among intrauterine and early postnatal exposure to undesirable modulators of metabolism, development of childhood obesity and later cardiometabolic complications. Special attention will be given to maternal dyslipidemia as a driven force for undesirable epigenetic modulations in offspring. In addition, newly proposed lipid biomarkers of increased cardiometabolic risk in obese children and adolescents will be analyzed, with respect to their predictive potential and clinical applicability.

Research Progress in Pharmacological Effects and Mechanisms of Angelica sinensis against Cardiovascular and Cerebrovascular Diseases

Angelica sinensis (Oliv.) Diels (A. sinensis) is a medicinal and edible values substance, which could promote blood circulation and enrich blood. It possesses rich chemical components and nutrients, which have significant therapeutic effects on cardiovascular and cerebrovascular diseases. It is commonly used for the prevention and treatment of cardiovascular and cerebrovascular diseases in the elderly, especially in improving ischemic damage to the heart and brain, protecting vascular cells, and regulating inflammatory reactions. This article reviews the main pharmacological effects and clinical research of A. sinensis on cardiovascular and cerebrovascular diseases in recent years, explores the effect of its chemical components on cardiovascular and cerebrovascular diseases by regulating the expression of functional proteins and inhibiting inflammation, anti-apoptosis, and antioxidant mechanisms. It provides a reference for further research on A. sinensis and the development of related drugs. It provides a new reference direction for the in-depth research and application of A. sinensis in the prevention, improvement, and treatment of cardiovascular and cerebrovascular diseases.

Rewiring Endothelial Sphingolipid Metabolism to Favor S1P Over Ceramide Protects From Coronary Atherosclerosis

BACKGROUND

Growing evidence correlated changes in bioactive sphingolipids, particularly S1P (sphingosine-1-phosphate) and ceramides, with coronary artery diseases. Furthermore, specific plasma ceramide species can predict major cardiovascular events. Dysfunction of the endothelium lining lesion-prone areas plays a pivotal role in atherosclerosis. Yet, how sphingolipid metabolism and signaling change and contribute to endothelial dysfunction and atherosclerosis remain poorly understood.

METHODS

We used an established model of coronary atherosclerosis in mice, combined with sphingolipidomics, RNA-sequencing, flow cytometry, and immunostaining to investigate the contribution of sphingolipid metabolism and signaling to endothelial cell (EC) activation and dysfunction.

RESULTS

We demonstrated that hemodynamic stress induced an early metabolic rewiring towards endothelial sphingolipid de novo biosynthesis, favoring S1P signaling over ceramides as a protective response. This finding is a paradigm shift from the current belief that ceramide accrual contributes to endothelial dysfunction. The enzyme SPT (serine palmitoyltransferase) commences de novo biosynthesis of sphingolipids and is inhibited by NOGO-B (reticulon-4B), an ER membrane protein. Here, we showed that NOGO-B is upregulated by hemodynamic stress in myocardial EC of ApoE-/- mice and is expressed in the endothelium lining coronary lesions in mice and humans. We demonstrated that mice lacking NOGO-B specifically in EC (Nogo-A/BECKOApoE-/-) were resistant to coronary atherosclerosis development and progression, and mortality. Fibrous cap thickness was significantly increased in Nogo-A/BECKOApoE-/- mice and correlated with reduced necrotic core and macrophage infiltration. Mechanistically, the deletion of NOGO-B in EC sustained the rewiring of sphingolipid metabolism towards S1P, imparting an atheroprotective endothelial transcriptional signature.

CONCLUSIONS

These data demonstrated that hemodynamic stress induced a protective rewiring of sphingolipid metabolism, favoring S1P over ceramide. NOGO-B deletion sustained the rewiring of sphingolipid metabolism toward S1P protecting EC from activation under hemodynamic stress and refraining coronary atherosclerosis. These findings also set forth the foundation for sphingolipid-based therapeutics to limit atheroprogression.

Circulating ceramide levels and ratios in Emirati youth under 18 years: associations with cardiometabolic risk factors

BACKGROUND

Circulating ceramide (Cer) drives various pathological processes associated with cardiovascular diseases, liver illness, and diabetes mellitus. Although recognized as predictors of cardiometabolic diseases (CMD) in research and clinical settings, their potential for predicting CMD risk in individuals under 18 remains unexplored.

OBJECTIVES

This study was designed to utilize Liquid Chromatography-Mass Spectrometry (LC-MS/MS) methodology to determine the biological reference ranges for Cer in plasma samples of Emirati children and develop a risk assessment score (CERT-1) based on Cer concentrations.

METHODS

Using LC-MS/MS, we developed a method to measure five Cer species in plasma samples of 582 Emirati participants aged 5-17. We used the circulating concentrations of these Cer to determine their reference intervals in this population. We employed traditional statistical analyses to develop a risk score (CERT-1) and assess the association between Cer levels and conventional biomarkers of CMD.

RESULTS

We validated a high-throughput methodology using LC-MS/MS to quantify five Cer species in human plasma. Reference values for this population (n = 582) were quantified: CerC16:0 (0.12-0.29 µmol/L), CerC18:0 (0.019-0.067 µmol/L), CerC22:0 (0.102-0.525 µmol/L), CerC24:0 (0.65-1.54 µmol/L) and CerC24:1 (0.212-0.945 µmol/L). We devised a risk assessment score (CERT-1) based on plasma Cer content in the study participants, showing that 72.5% have low to moderate risk and 9.3% are at a higher risk of developing CMD. Our analyses also revealed a significant correlation (P < 0.05) between this score and the conventional risk factors linked to CMD, indicating its potential clinical implication.

CONCLUSION

This study presents a clinical-scaled LC-MS/MS methodology for assessing clinically relevant Cer, setting reference ranges, and developing a risk score (CERT-1) for young Emirati individuals. Our findings can enhance primary risk prediction and inform the management and follow-up of CMD from an early age.

Ceramides Mediate Insulin-Induced Impairments in Cerebral Mitochondrial Bioenergetics in ApoE4 Mice

Alzheimer's disease (AD) is the most common form of neurodegenerative disease worldwide. A large body of work implicates insulin resistance in the development and progression of AD. Moreover, impairment in mitochondrial function, a common symptom of insulin resistance, now represents a fundamental aspect of AD pathobiology. Ceramides are a class of bioactive sphingolipids that have been hypothesized to drive insulin resistance. Here, we describe preliminary work that tests the hypothesis that hyperinsulinemia pathologically alters cerebral mitochondrial function in AD mice via accrual of the ceramides. Homozygous male and female ApoE4 mice, an oft-used model of AD research, were given chronic injections of PBS (control), insulin, myriocin (an inhibitor of ceramide biosynthesis), or insulin and myriocin over four weeks. Cerebral ceramide content was assessed using liquid chromatography-mass spectrometry. Mitochondrial oxygen consumption rates were measured with high-resolution respirometry, and H2O2 emissions were quantified via biochemical assays on brain tissue from the cerebral cortex. Significant increases in brain ceramides and impairments in brain oxygen consumption were observed in the insulin-treated group. These hyperinsulinemia-induced impairments in mitochondrial function were reversed with the administration of myriocin. Altogether, these data demonstrate a causative role for insulin in promoting brain ceramide accrual and subsequent mitochondrial impairments that may be involved in AD expression and progression.

Plasma Ceramides and Sphingomyelins and Sudden Cardiac Death in the Cardiovascular Health Study

Importance

Sphingolipids, including ceramides and sphingomyelins, may influence the pathophysiology and risk of sudden cardiac death (SCD) through multiple biological activities. Whether the length of the fatty acid acylated to plasma sphingolipid species is associated with SCD risk is not known.

Objective

To determine whether the saturated fatty acid length of plasma ceramides and sphingomyelins influences the association with SCD risk.

Design, Setting, and Participants

In this cohort study, multivariable Cox proportional hazards regression models were used to examine the association of sphingolipid species with SCD risk. The study population included 4612 participants in the Cardiovascular Health Study followed up prospectively for a median of 10.2 (IQR, 5.5-11.6) years. Baseline data were collected from January 1992 to December 1995 during annual examinations. Data were analyzed from February 11, 2020, to September 9, 2023.

Exposures

Eight plasma sphingolipid species (4 ceramides and 4 sphingomyelins) with saturated fatty acids of 16, 20, 22, and 24 carbons.

Main Outcome and Measure

Association of plasma ceramides and sphingomyelins with saturated fatty acids of different lengths with SCD risk.

Results

Among the 4612 CHS participants included in the analysis (mean [SD] age, 77 [5] years; 2724 [59.1%] women; 6 [0.1%] American Indian; 4 [0.1%] Asian; 718 [15.6%] Black; 3869 [83.9%] White, and 15 [0.3%] Other), 215 SCD cases were identified. In adjusted Cox proportional hazards regression analyses, plasma ceramides and sphingomyelins with palmitic acid (Cer-16 and SM-16) were associated with higher SCD risk per higher SD of log sphingolipid levels (hazard ratio [HR] for Cer-16, 1.34 [95% CI, 1.12-1.59]; HR for SM-16, 1.37 [95% CI, 1.12-1.67]). Associations did not differ by baseline age, sex, race, or body mass index. No significant association of SCD with sphingolipids with very-long-chain saturated fatty acids was observed after correction for multiple testing (HR for ceramide with arachidic acid, 1.06 [95% CI, 0.90-1.24]; HR for ceramide with behenic acid, 0.92 [95% CI, 0.77-1.10]; HR for ceramide with lignoceric acid, 0.92 [95% CI, 0.77-1.09]; HR for sphingomyelin with arachidic acid, 0.83 [95% CI, 0.71-0.98]; HR for sphingomyelin with behenic acid, 0.84 [95% CI, 0.70-1.00]; HR for sphingomyelin with lignoceric acid, 0.86 [95% CI, 0.72-1.03]).

Conclusions and Relevance

The findings of this large, population-based cohort study of SCD identified that higher plasma levels of Cer-16 and SM-16 were associated with higher risk of SCD. Future studies are needed to examine the underlying mechanism of these associations.

Ceramide d18:1/24:1 as a potential biomarker to differentiate obesity subtypes with unfavorable health outcomes

BACKGROUND

The criteria for metabolically healthy obesity (MHO) and metabolically unhealthy obesity (MUO) remain controversial. This research aimed to identify a potential biomarker to differentiate the subtypes of obesity.

METHODS

The study conducted a lipidomic evaluation of ceramide in the serum of 77 Chinese adults who had undergone hyperinsulinemic-euglycemic clamps. These adults were divided into three groups according to the clinical data: normal weight control group (N = 21), MHO (N = 20), and MUO (N = 36).

RESULTS

The serum Cer d18:1/24:1 level in the MHO group was lower than that in the MUO group. As the Cer d18:1/24:1 level increased, insulin sensitivity decreased, and the unfavorable parameters increased in parallel. Multivariate logistic regression analysis revealed that serum Cer d18:1/24:1 levels were independently correlated with MUO in obesity. Individuals with higher levels of Cer d18:1/24:1 also had an elevated risk of cardiovascular disease. Most ceramide subtype levels increased in obesity compared to normal-weight individuals, but the levels of serum Cer d18:0/18:0 and Cer d18:1/16:0 decreased in obesity.

CONCLUSIONS

The relationships between ceramide subtypes and metabolic profiles might be heterogeneous in populations with different body weights. Cer d18:1/24:1 could be a biomarker that can be used to differentiate MUO from MHO, and to better predict who will develop unfavorable health outcomes among obese individuals.

TRIAL REGISTRATION

The First Affiliated Hospital of Nanjing Medical University's Institutional Review Board authorized this study protocol, and all participants provided written informed consent (2014-SR-003) prior to study entry.

Longitudinal lipidomic signature of carotid atherosclerosis in American Indians: Findings from the Strong Heart Family Study

BACKGROUND AND AIMS

Dyslipidemia is an independent risk factor for atherosclerosis and atherosclerotic cardiovascular disease (ASCVD). To date, a comprehensive assessment of individual lipid species associated with atherosclerosis is lacking in large-scale epidemiological studies, especially in a longitudinal setting. We investigated the association of circulating lipid species and its longitudinal changes with carotid atherosclerosis.

METHODS

Using liquid chromatograph-mass spectrometry, we repeatedly measured 1542 lipid species in 3687 plasma samples from 1918 unique American Indians attending two visits (mean ∼5 years apart) in the Strong Heart Family Study. Carotid atherosclerotic plaques were assessed by ultrasonography at each visit. We identified lipids associated with prevalence or progression of carotid plaques, adjusting age, sex, BMI, smoking, hypertension, diabetes, and eGFR. Then we examined whether longitudinal changes in lipids were associated with changes in cardiovascular risk factors. Multiple testing was controlled at false discovery rate (FDR) < 0.05.

RESULTS

Higher levels of sphingomyelins, ether-phosphatidylcholines, and triacylglycerols were significantly associated with prevalence or progression of carotid plaques (odds ratios ranged from 1.15 to 1.34). Longitudinal changes in multiple lipid species (e.g., acylcarnitines, phosphatidylcholines, triacylglycerols) were associated with changes in cardiometabolic traits (e.g., BMI, blood pressure, fasting glucose, eGFR). Network analysis identified differential lipid networks associated with plaque progression.

CONCLUSIONS

Baseline and longitudinal changes in multiple lipid species were significantly associated with carotid atherosclerosis and its progression in American Indians. Some plaque-related lipid species were also associated with risk for CVD events.

Diet-derived and diet-related endogenously produced palmitic acid: Effects on metabolic regulation and cardiovascular disease risk

Palmitic acid is the predominant dietary saturated fatty acid (SFA) in the US diet. Plasma palmitic acid is derived from dietary fat and also endogenously from de novo lipogenesis (DNL) and lipolysis. DNL is affected by excess energy intake resulting in overweight and obesity, and the macronutrient profile of the diet. A low-fat diet (higher carbohydrate and/or protein) promotes palmitic acid synthesis in adipocytes and the liver. A high-fat diet is another source of palmitic acid that is taken up by adipose tissue, liver, heart and skeletal muscle via lipolytic mechanisms. Moreover, overweight/obesity and accompanying insulin resistance increase non-esterified fatty acid (NEFA) production. Palmitic acid may affect cardiovascular disease (CVD) risk via mechanisms beyond increasing low-density lipoprotein-cholesterol (LDL-C), notably synthesis of ceramides and possibly through branched fatty acid esters of hydroxy fatty acids (FAHFAs) from palmitic acid. Ceramides are positively associated with incident CVD, whereas the role of FAHFAs is uncertain. Given the new evidence about dietary regulation of palmitic acid metabolism there is interest in learning more about how diet modulates circulating palmitic acid concentrations and, hence, potentially CVD risk. This is important because of the heightened interest in low carbohydrate (carbohydrate controlled) and high carbohydrate (low-fat) diets coupled with the ongoing overweight/obesity epidemic, all of which can increase plasma palmitic acid levels by different mechanisms. Consequently, learning more about palmitic acid biochemistry, trafficking and how its metabolites affect CVD risk will inform future dietary guidance to further lower the burden of CVD.

The therapeutic potential of sphingolipids for cardiovascular diseases

Cardiovascular diseases (CVDs) are the leading cause of morbidity and mortality worldwide and Inflammation plays a critical role in the development of CVD. Despite considerable progress in understanding the underlying mechanisms and various treatment options available, significant gaps in therapy necessitate the identification of novel therapeutic targets. Sphingolipids are a family of lipids that have gained attention in recent years as important players in CVDs and the inflammatory processes that underlie their development. As preclinical studies have shown that targeting sphingolipids can modulate inflammation and ameliorate CVDs, targeting sphingolipids has emerged as a promising therapeutic strategy. This review discusses the current understanding of sphingolipids' involvement in inflammation and cardiovascular diseases, the existing therapeutic approaches and gaps in therapy, and explores the potential of sphingolipids-based drugs as a future avenue for CVD treatment.

Marked elevations in lung and plasma ceramide in COVID-19 linked to microvascular injury

The pathogenesis of the marked pulmonary microvasculature injury, a distinguishing feature of COVID-19 acute respiratory distress syndrome (COVID-ARDS), remains unclear. Implicated in the pathophysiology of diverse diseases characterized by endothelial damage, including ARDS and ischemic cardiovascular disease, ceramide and in particular palmitoyl ceramide (C16:0-ceramide) may be involved in the microvascular injury in COVID-19. Using deidentified plasma and lung samples from COVID-19 patients, ceramide profiling by mass spectrometry was performed. Compared with healthy individuals, a specific 3-fold C16:0-ceramide elevation in COVID-19 patient plasma was identified. Compared with age-matched controls, autopsied lungs of individuals succumbing to COVID-ARDS displayed a massive 9-fold C16:0-ceramide elevation and exhibited a previously unrecognized microvascular ceramide-staining pattern and markedly enhanced apoptosis. In COVID-19 plasma and lungs, the C16-ceramide/C24-ceramide ratios were increased and reversed, respectively, consistent with increased risk of vascular injury. Indeed, exposure of primary human lung microvascular endothelial cell monolayers to C16:0-ceramide-rich plasma lipid extracts from COVID-19, but not healthy, individuals led to a significant decrease in endothelial barrier function. This effect was phenocopied by spiking healthy plasma lipid extracts with synthetic C16:0-ceramide and was inhibited by treatment with ceramide-neutralizing monoclonal antibody or single-chain variable fragment. These results indicate that C16:0-ceramide may be implicated in the vascular injury associated with COVID-19.

Cohort study examining associations between ceramide levels and risk of multimorbidity among persons participating in the Mayo Clinic Biobank

OBJECTIVE

Ceramides have been associated with several ageing-related conditions but have not been studied as a general biomarker of multimorbidity (MM). Therefore, we determined whether ceramide levels are associated with the rapid development of MM.

DESIGN

Retrospective cohort study.

SETTING

Mayo Clinic Biobank.

PARTICIPANTS

1809 persons in the Mayo Clinic Biobank ≥65 years without MM at the time of enrolment, and with ceramide levels assayed from stored plasma.

PRIMARY OUTCOME MEASURE

Persons were followed for a median of 5.7 years through their medical records to identify new diagnoses of 20 chronic conditions. The number of new conditions was divided by the person-years of follow-up to calculate the rate of accumulation of new chronic conditions.

RESULTS

Higher levels of C18:0 and C20:0 were associated with a more rapid rate of accumulation of chronic conditions (C18:0 z score RR: 1.30, 95% CI: 1.10 to 1.53; C20:0 z score RR: 1.26, 95% CI: 1.07 to 1.49). Higher C18:0 and C20:0 levels were also associated with an increased risk of hypertension and coronary artery disease.

CONCLUSIONS

C18:0 and C20:0 were associated with an increased risk of cardiometabolic conditions. When combined with biomarkers specific to other diseases of ageing, these ceramides may be a useful component of a biomarker panel for predicting accelerated ageing.

Replacement of dietary saturated with unsaturated fatty acids is associated with beneficial effects on lipidome metabolites: a secondary analysis of a randomized trial

BACKGROUND

The effects of replacing dietary saturated fatty acids (SFAs) with monounsaturated fatty acids (MUFAs) and/or polyunsaturated fatty acids (PUFAs) on the plasma lipidome in relation to the cardiometabolic disease (CMD) risk are poorly understood.

OBJECTIVES

We aimed to assess the impact of substituting dietary SFAs with unsaturated fatty acids (UFAs) on the plasma lipidome and examine the relationship between lipid metabolites modulated by diet and CMD risk.

METHODS

Plasma fatty acid (FA) concentrations among 16 lipid classes (within-class FAs) were measured in a subgroup from the Dietary Intervention and VAScular function (DIVAS) parallel randomized controlled trial (n = 113/195), which consisted of three 16-wk diets enriched in SFAs (target SFA:MUFA:n-6PUFA ratio = 17:11:4% total energy [TE]), MUFAs (9:19:4% TE), or a MUFA/PUFA mixture (9:13:10% TE). Similar lipidomics analyses were conducted in the European investigation into Cancer and Nutrition (EPIC)-Potsdam prospective cohort study (specific case/cohorts: n = 775/1886 for type 2 diabetes [T2D], n = 551/1671 for cardiovascular disease [CVD]). Multiple linear regression and multivariable Cox models identified within-class FAs sensitive to replacement of dietary SFA with UFA in DIVAS and their association with CMD risk in EPIC-Potsdam. Elastic-net regression models identified within-class FAs associated with changes in CMD risk markers post-DIVAS interventions.

RESULTS

DIVAS high-UFA interventions reduced plasma within-class FAs associated with a higher CVD risk in EPIC-Potsdam, especially SFA-containing glycerolipids and sphingolipids (e.g., diacylglycerol (20:0) z-score = -1.08; SE = 0.17; P value < 10^-8), whereas they increased those inversely associated with CVD risk. The results on T2D were less clear. Specific sphingolipids and phospholipids were associated with changes in markers of endothelial function and ambulatory blood pressure, whereas higher low-density lipoprotein cholesterol concentrations were characterized by higher plasma glycerolipids containing lauric and stearic acids.

CONCLUSIONS

These results suggest a mediating role of plasma lipid metabolites in the association between dietary fat and CMD risk. Future research combining interventional and observational findings will further our understanding of the role of dietary fat in CMD etiology. This trial was registered in ClinicalTrials.gov as NCT01478958.

Clinical lipidomics in the era of the big data

Lipidomics as a branch of metabolomics provides unique information on the complex lipid profile in biological materials. In clinically focused studies, hundreds of lipids together with available clinical information proved to be an effective tool in the discovery of biomarkers and understanding of pathobiochemistry. However, despite the introduction of lipidomics nearly twenty years ago, only dozens of big data studies using clinical lipidomics have been published to date. In this review, we discuss the lipidomics workflow, statistical tools, and the challenges of standartisation. The consequent summary divided into major clinical areas of cardiovascular disease, cancer, diabetes mellitus, neurodegenerative and liver diseases is demonstrating the importance of clinical lipidomics. In these publications, the potential of lipidomics for prediction, diagnosis or finding new targets for the treatment of selected diseases can be seen. The first of these results have already been implemented in clinical practice in the field of cardiovascular diseases, while in other areas we can expect the application of the results summarized in this review in the near future.

Four-dimensional trapped ion mobility spectrometry lipidomics for high throughput clinical profiling of human blood samples

Lipidomics encompassing automated lipid extraction, a four-dimensional (4D) feature selection strategy for confident lipid annotation as well as reproducible and cross-validated quantification can expedite clinical profiling. Here, we determine 4D descriptors (mass to charge, retention time, collision cross section, and fragmentation spectra) of 200 lipid standards and 493 lipids from reference plasma via trapped ion mobility mass spectrometry to enable the implementation of stringent criteria for lipid annotation. We use 4D lipidomics to confidently annotate 370 lipids in reference plasma samples and 364 lipids in serum samples, and reproducibly quantify 359 lipids using level-3 internal standards. We show the utility of our 4D lipidomics workflow for high-throughput applications by reliable profiling of intra-individual lipidome phenotypes in plasma, serum, whole blood, venous and finger-prick dried blood spots.

The interplay between nonalcoholic fatty liver disease and atherosclerotic cardiovascular disease

Therapeutic approaches that lower circulating low-density lipoprotein (LDL)-cholesterol significantly reduced the burden of cardiovascular disease over the last decades. However, the persistent rise in the obesity epidemic is beginning to reverse this decline. Alongside obesity, the incidence of nonalcoholic fatty liver disease (NAFLD) has substantially increased in the last three decades. Currently, approximately one third of world population is affected by NAFLD. Notably, the presence of NAFLD and particularly its more severe form, nonalcoholic steatohepatitis (NASH), serves as an independent risk factor for atherosclerotic cardiovascular disease (ASCVD), thus, raising interest in the relationship between these two diseases. Importantly, ASCVD is the major cause of death in patients with NASH independent of traditional risk factors. Nevertheless, the pathophysiology linking NAFLD/NASH with ASCVD remains poorly understood. While dyslipidemia is a common risk factor underlying both diseases, therapies that lower circulating LDL-cholesterol are largely ineffective against NASH. While there are no approved pharmacological therapies for NASH, some of the most advanced drug candidates exacerbate atherogenic dyslipidemia, raising concerns regarding their adverse cardiovascular consequences. In this review, we address current gaps in our understanding of the mechanisms linking NAFLD/NASH and ASCVD, explore strategies to simultaneously model these diseases, evaluate emerging biomarkers that may be useful to diagnose the presence of both diseases, and discuss investigational approaches and ongoing clinical trials that potentially target both diseases.

Ceramides and Phosphatidylcholines Associate with Cardiovascular Diseases in the Elderly

Background

The ceramide- and phospholipid-based cardiovascular risk score (CERT2) has been found to predict the risk for cardiovascular disease (CVD) events, especially cardiovascular mortality. In the present study, our aim was to estimate the predictive ability of CERT2 for mortality of CVD, coronary artery disease (CAD), and stroke in the elderly and to compare these results with those of conventional lipids.

Methods

We conducted a prospective study with an 18-year follow-up period that included a total of 1260 participants ages ≥64 years. Ceramides and phosphatidylcholines were analyzed using a LC-MS. Total cholesterol and triglycerides were performed by enzymatic methods and HDL cholesterol was determined by a direct enzymatic method. Concentrations of LDL-cholesterol were calculated according to the Friedewald formula.

Results

A higher score of CERT2 was significantly associated with higher CVD, CAD, and stroke mortality during the 18-year follow-up both in unadjusted and adjusted Cox regression models. The unadjusted hazard ratios (HRs) of CERT2 (95% CI) per SD for CVD, CAD, and stroke were 1.72 (1.52–1.96), 1.76 (1.52–2.04), and 1.63 (1.27–2.10), respectively, and the corresponding adjusted HRs (95% CI) per SD for CERT2 were 1.48 (1.29–1.69), 1.50 (1.28–1.75), and 1.41 (1.09–1.83). For conventional lipids, HRs per SD were lower than for CERT2.

Conclusions

The risk score CERT2 associated strongly with CVD, CAD, and stroke mortality in the elderly, while the association between these events and conventional lipids was weak.

Ceramide Acyl Chain Length and Its Relevance to Intracellular Lipid Regulation

Ceramides are a class of sphingolipids which are implicated in skin disorders, obesity, and other metabolic diseases. As a class with pleiotropic effects, recent efforts have centred on discerning specific ceramide species and their effects on atopic dermatitis, obesity, type 2 diabetes, and cardiovascular diseases. This delineation has allowed the identification of disease biomarkers, with long acyl chain ceramides such as C16- and C18-ceramides linked to metabolic dysfunction and cardiac function decline, while ultra-long acyl chain ceramides (>25 carbon acyl chain) were reported to be essential for maintaining a functional skin barrier. Given the intricate link between free fatty acids with ceramides, especially the de novo synthetic pathway, intracellular lipid droplet formation is increasingly viewed as an important mechanism for preventing accumulation of toxic ceramide species. Here, we review recent reports of various ceramide species involved in skin abnormalities and metabolic diseases, and we propose that promotion of lipid droplet biogenesis can be seen as a potential protective mechanism against deleterious ceramides.

Alirocumab and Lipid Levels, Inflammatory Biomarkers, Metabolomics, and Safety in Maintenance Dialysis Patients: The ALIDIAL Study (A Phase III Trial to Evaluate the Efficacy and Safety of Biweekly Alirocumab in Patients on a Stable Dialysis Regimen)

Rationale & Objective

The proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitor alirocumab is used in the general population to treat dyslipidemia, but little is known about the effects of alirocumab on lipid levels, biomarkers, the metabolome, and safety in individuals receiving maintenance dialysis.

Study Design

Patients receiving maintenance dialysis for at least 3 months and with a low-density lipoprotein cholesterol level of >70 mg/dL were treated with alirocumab for 12 weeks. Laboratory measurements, drug levels, and safety assessments were obtained at baseline and every 4 weeks during the trial.

Setting & Participants

In an outpatient setting, 14 patients completed the trial.

Intervention

The patients were treated with alirocumab at a full dose of 150 mg every 2 weeks for 12 weeks. The patients were asked to report any adverse events every 2 weeks.

Outcomes

There were no unexpected adverse events or laboratory abnormalities in this population receiving dialysis. The drug levels were the same as those for a population not receiving dialysis.

Results

Alirocumab resulted in a 45% reduction in the low-density lipoprotein cholesterol level (P = 0.005) and a 35% reduction in the apolipoprotein B level (P = 0.06). There were no significant decreases in the levels of triglycerides, C-reactive protein, fibrinogen, or other inflammatory biomarkers tested. There were significant decreases in the levels of 7 ceramide, 5 sphingomyelin, and 5 cholesterol ester species.

Limitations

This study was performed in only 14 patients who were administered alirocumab for only 12 weeks. This study did not address alirocumab treatment in patients with chronic kidney disease not receiving maintenance dialysis.

Conclusions

Individuals receiving maintenance dialysis had a similar response to the PCSK9 inhibitor alirocumab as patients not receiving dialysis. The levels of inflammatory biomarkers were not clearly decreased by alirocumab, but the levels of ceramides, sphingomyelins, and cholesterol esters were significantly reduced.

Trial Registration

Clinical Trials.gov as NCT03480568.

Plasma Ceramide Levels Are Elevated in Patients With Early Coronary Atherosclerosis and Endothelial Dysfunction

Background

Elevated plasma ceramides are independent predictors of cardiovascular disease and mortality in patients with advanced epicardial coronary artery disease. Our understanding of plasma ceramides in early epicardial coronary artery disease, however, remains limited. We examined the role of plasma ceramides in early coronary atherosclerosis characterized by coronary endothelial dysfunction.

Methods and Results

Participants presenting with chest pain and nonobstructive epicardial coronary artery disease underwent coronary endothelial function. Patients (n=90) demonstrated abnormal coronary endothelial function with acetylcholine (≥20% decrease in coronary artery diameter or ≤50% increase in coronary blood flow). A total of 30 controls had normal coronary endothelial function. Concentrations of plasma ceramide 18:0 (P=0.038), 16:0 (P=0.021), and 24:0 (P=0.019) differed between participants with normal and abnormal coronary endothelial function. Ceramide 24:0 (odds ratio [OR], 2.23 [95% CI, 1.07–4.66]; P=0.033) and 16:0 (OR, 1.91×10⁶ [95% CI, 11.93–3.07×10¹¹]; P=0.018) were independently associated with coronary endothelial dysfunction. Among participants with endothelium‐dependent coronary dysfunction (n=78), ceramides 16:0 (OR, 5.17×10⁵ [95% CI, 2.83–9.44×10¹⁰]; P=0.033), 24:0 (OR, 2.98 [95% CI, 1.27–7.00]; P=0.012), and 24:1/24:0 (OR, 4.39×10⁻⁴ [95% CI, 4×10⁻⁷–0.48]; P=0.030) were more likely to be elevated.

Conclusions

The current study demonstrated an association between increased circulating ceramide levels and coronary endothelial dysfunction in the absence of epicardial coronary artery disease. This study supports the role of plasma ceramides as a potential biomarker or a therapeutic target for early coronary atherosclerosis in humans.

Emerging Roles of Ceramide in Cardiovascular Diseases

Ceramide is a core molecule of sphingolipid metabolism that causes selective insulin resistance and dyslipidemia. Research on its involvement in cardiovascular diseases has grown rapidly. In resting cells, ceramide levels are extremely low, while they rapidly accumulate upon encountering external stimuli. Recently, the regulation of ceramide levels under pathological conditions, including myocardial infarction, hypertension, and atherosclerosis, has drawn great attention. Increased ceramide levels are strongly associated with adverse cardiovascular risks and events while inhibiting the synthesis of ceramide or accelerating its degradation improves a variety of cardiovascular diseases. In this article, we summarize the role of ceramide in cardiovascular disease, investigate the possible application of ceramide as a new diagnostic biomarker and a therapeutic target for cardiovascular disorders, and highlight the remaining problems.

NMMHC IIA triggered lipid metabolize reprogramming resulting in vascular endothelial cellular tight junction injury

BACKGROUND AND PURPOSE

Nonmuscle myosin heavy chain IIA, played an essential role in the promotion of tight junction injury in vascular endothelial cells under oxygen glucose deprivation condition. Rat microvascular endothelial cells had been confirmed to have the susceptibility to ox-LDL stimulation under OGD condition. We proposed the hypothesis that lipid metabolic reprogramming might be the root cause for damage to RBMCs tight junction.

METHODS

Untargeted shotgun and targeted lipid metabolomics mass spectrometry approaches combined with principal component analysis was applied to better define the lipids contributing to the variance observed between control and different OGD time. The protein expression of tight junction of RBMCs: occludin, claudin-5, and ZO-1 were detected with immunofluorescence staining and western blot. The proof of the interaction between NMMHC IIA and SREBP1 was investigated via GST-pull down, while their specific binding fragments were also confirmed. The regulation mechanism of NMMHC IIA on SREBP1 was investigated to explore downstream regulatory signaling pathways.

RESULTS

Untargeted and targeted shotgun lipidomics data revealed that OGD might be the conditional factor in reshaping lipid components. Mechanistic studies showed that with the increase of OGD time, PCA analysis of lipidomics obtained from RBMCs indicated their specificity in reshaping lipid components, while ≥80% major lipid components phospholipids and sphingolipids transferred from phospholipids, sphingolipids, and neutral lipids, of which neutral lipids taken the largest proportion with OGD time course. Perturbing reprogramming of lipid composition was less susceptible to OGD condition via knockdown of NMMHC IIA of vascular endothelial cells. Knockdown of NMMHC IIA could promote tight junction defense to OGD condition. NMMHC IIA could directly bind with SREBP1, then could affect sterol regulatory element binding protein-1 to adjust lipid metabolize reprogramming of RBMCs.

CONCLUSIONS

Mechanistic studies showed that perturbing reprogramming of lipid composition could enhance tight junction damage, which was mediated by the opposing effects of NMMHC IIA.

Effects of Wine and Tyrosol on the Lipid Metabolic Profile of Subjects at Risk of Cardiovascular Disease: Potential Cardioprotective Role of Ceramides

Ceramides are a class of sphingolipids which have recently been shown to be better cardiovascular disease (CVD) risk predictors than traditional CVD risk biomarkers. Tyrosol (TYR) is a dietary phenolic compound known to possess cardioprotective effects per se or through its in vivo active metabolite hydroxytyrosol. The purpose of this study was to evaluate the effects of the co-administration of white wine (WW) and TYR on circulating levels of ceramides and other lipids in humans at high CVD risk. Volunteers underwent a randomized controlled crossover clinical trial (4-week duration per intervention) with three different interventions: control, WW, and WW enriched with a capsule of TYR (WW + TYR). Endothelial function cardiovascular biomarkers and plasma lipidomic profile were assessed before and after each intervention. It was found that the WW + TYR intervention resulted in lower levels of three ceramide ratios, associated with an improvement of endothelial function (Cer C16:0/Cer C24:0, Cer C18:0/Cer C24:0, and Cer C24:1/Cer C24:0), when compared to the control intervention. Moreover, WW + TYR was able to minimize the alterations in plasma diacylglycerols concentrations observed following WW. Overall, the results obtained show that the antioxidant TYR administered with WW exerts beneficial effects at the cardiovascular level, in part by modulating blood lipid profile.

Coffee, Atrial Fibrillation, and Circulating Ceramides in Patients with Chronic Heart Failure

Ceramides are sphingolipids that play roles as structural lipids and as second messengers in biological processes. Circulating ceramides are influenced by diet/food and predict major cardiovascular (CV) events, such as atrial fibrillation (AF). In 1227 patients with symptomatic chronic heart failure (HF), an association between diet and ceramides was found for coffee consumption of ≥3 cups and Cer(d18:1/24:0). Increased Cer(d18:1/24:0) was associated with lower incident AF (24.3% vs 15.4% tertile 1 vs 3, P = 0.016) and lower CV mortality (28.4% vs 12.0% tertile 1 vs 3, P < 0.0001). For coffee consumption, only an association with incident AF was found (24.5% never, 5.2% ≥3 cups). These inverse associations with AF were confirmed in survival analyses corrected for biomarkers (Cer(d18:1/24:0) HR: 0.79, P = 0.018; coffee consumption HR: 0.22, P = 0.001). In conclusion, higher coffee intake was associated with a lower risk of incident AF and with higher concentrations of Cer(d18:1/24:0). Cer(d18:1/24:0) was inversely associated to risk of AF.

(-)-Epicatechin gallate blocks the development of atherosclerosis by regulating oxidative stress in vivo and in vitro

(-)-Epicatechin gallate (ECG), as a compound in green tea extract polyphenols, has specific therapeutic effects against oxidative stress. Oxidative stress exists throughout the pathological development of atherosclerosis. In this study, two atherosclerosis models, oxidized low-density lipoprotein (ox-LDL)-induced vascular smooth muscle cells (VSMCs) and high fat diet (HFD)-induced ApoE-/- mice, were applied to explore the mechanism of ECG intervention on AS. In vivo and in vitro studies showed that ECG reduced the level of MDA and increased the activity of SOD, which are oxidative stress factors. ECG also improved HFD-induced disorder of lipid factor expression in the serum of ApoE-/- mice and alleviated oxidative stress by enhancing the antioxidant activity. The potential mechanism was supposed to be the inhibition of the phosphorylation of p65 by ECG in the NF-κB pathway in the aorta, thereby blocking the expression of inflammatory mediators. In addition, ECG increased the stability of atherosclerosis plaques by reducing the expression of MMP-2 and ICAM-1 in atherosclerosis diseased tissues. ECG reduced lipid accumulation in the aorta and its roots and also plaque neoplasia. Western blotting experiments indicated that ECG increased the nuclear transfer of Nrf2 and the expression of heme oxygenase 1 (HO-1) was increased. These results demonstrated that ECG significantly reduced the formation of aortic plaque in ApoE-/- mice which was possibly triggered by the inhibition of hyperlipidemia and oxidative stress that exhibited the anti-atherosclerotic potential.

Ceramide Scores Predict Cardiovascular Risk in the Community

[Figure: see text].

Serum Ceramides as Prognostic Biomarkers of Large Thrombus Burden in Patients with STEMI: A Micro-Computed Tomography Study

ST-elevation myocardial infarction (STEMI) remains one of the leading causes of mortality worldwide. The identification of novel metabolic and imaging biomarkers could unveil key pathophysiological mechanisms at the molecular level and promote personalized care in patients with acute coronary syndromes. We studied 38 patients with STEMI who underwent primary percutaneous coronary intervention and thrombus aspiration. We sought to correlate serum ceramide levels with micro-CT quantified aspirated thrombus volume and relevant angiographic outcomes, including modified TIMI thrombus grade and pre- or post-procedural TIMI flow. Higher ceramide C16:0 levels were significantly but weakly correlated with larger aspirated thrombus volume (Spearman r = 0.326, p = 0.046), larger intracoronary thrombus burden (TB; p = 0.030) and worse pre- and post-procedural TIMI flow (p = 0.049 and p = 0.039, respectively). Ceramides C24:0 and C24:1 were also significantly associated with larger intracoronary TB (p = 0.008 and p = 0.001, respectively). Receiver operating characteristic analysis demonstrated that ceramides C24:0 and C24:1 could significantly predict higher intracoronary TB (area under the curve: 0.788, 95% CI: 0.629-0.946 and 0.846, 95% CI: 0.706-0.985, respectively). In conclusion, serum ceramide levels were higher among patients with larger intracoronary and aspirated TB. This suggests that quantification of serum ceramides might improve risk-stratification of patients with STEMI and facilitate an individualized approach in clinical practice.