PCSK9 inhibition alters the lipidome of plasma and lipoprotein fractions

Lipidomics and cardiovascular disease

Cardiovascular diseases (CVDs) remain the leading cause of mortality worldwide, necessitating innovative approaches for early detection and personalized interventions. Lipidomics, leveraging advanced mass spectrometry techniques, has become instrumental in deciphering lipid-mediated mechanisms in CVDs. This review explores the application of lipidomics in identifying biomarkers for myocardial infarction, heart failure, stroke, and calcific aortic valve stenosis (CAVS). This review examines the technological advancements in shotgun lipidomics and LC/MS, which provide unparalleled insights into lipid composition and function. Key lipid biomarkers, including ceramides and lysophospholipids, have been linked to disease progression and therapeutic outcomes. Integrating lipidomics with genomic and proteomic data reveals the molecular underpinnings of CVDs, enhancing risk prediction and intervention strategies. This review positions lipidomics as a transformative tool in reshaping cardiovascular research and clinical practice.

Ceramide in Coronary Artery Disease: Troublesome or Helpful Future Tools in the Assessment of Risk Prediction and Therapy Effectiveness?

Lipids are a complex entity of different molecules, among which ceramides (Cers), ubiquitous sphingolipids with remarkable biological activity, can represent a potential additive biomarker that can be used to better understand the underlying mechanisms which drive the onset and development of atherosclerotic damage and plaque vulnerability and facilitate coronary disease management, as possible risk/prognostic biomarkers and targets for therapeutic intervention. Accordingly, this review aims to discuss the available results on the role Cersplay in contributing to atherosclerosis development and acute coronary event precipitation, their impact on complications and adverse prognosis, as well as the impact of treatment options in modulating Cerlevels.

Lack of renoprotective effects by long-term PCSK9 and SGLT2 inhibition using alirocumab and empagliflozin in obese ZSF1 rats

Chronic kidney disease (CKD) is associated with an increased risk of cardiovascular disease (CVD). Despite the entry of sodium glucose cotransporter 2 (SGLT2) inhibitors, CKD persists as a medical challenge. Proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibition reduces low-density lipoprotein (LDL)-cholesterol, a major risk factor of CVD. Interestingly, studies indicate that PCSK9 inhibition decreases proteinuria in kidney disease, complementing the reduced CVD risk. This study aimed to validate obese ZSF1 rats as a model for the renoprotective effects of PCSK9 and SGLT2 inhibition using alirocumab and empagliflozin for 15 wk. Obese rats revealed a significant reduction in measured glomerular filtration rate (mGFR) and increased urine albumin/creatinine ratio (UACR) during follow-up compared with lean controls. Alirocumab treatment resulted in a decline in mGFR and increased UACR compared with vehicle-treated obese rats. Immunohistochemistry showed increased fibrosis and inflammation in kidney tissue from obese rats treated with empagliflozin or alirocumab, whereas hepatic cholesterol and triglyceride levels were lowered compared with vehicle-treated obese rats. Although alirocumab lowered circulating free cholesterol levels throughout the treatment period, certain cholesteryl esters were increased at the end of the study, resulting in no overall difference in total cholesterol levels in the alirocumab group. Correspondingly, only a trend toward increased hepatic LDL-receptor levels was observed. In conclusion, these findings suggest that alirocumab treatment aggravates kidney dysfunction in obese ZSF1 rats. Moreover, in contrast to the renoprotective properties of empagliflozin observed in patients with CKD, empagliflozin did not ameliorate kidney disease progression in the obese ZSF1 rat.NEW & NOTEWORTHY New treatments to slow kidney disease progression and reduce cardiovascular disease risk are needed for chronic kidney disease (CKD). We investigated the cholesterol-lowering PCSK9 inhibitor alirocumab as a new treatment for proteinuric CKD and the effect of SGLT2 inhibition using empagliflozin in obese ZSF1 rats. Regarding renoprotection, our findings were contradictory with previous preclinical studies and clinical data, suggesting that different pathophysiological mechanisms may apply to this rat model.

Evolocumab in metastatic castration-resistant prostate cancer: study protocol for a single-arm, phase II trial, and initial experience with use of a validated lipid biomarker to direct therapy

Background

Despite advances in the treatment of metastatic castration-resistant prostate cancer (mCRPC), primary and secondary resistance to current therapies remains. Elevated circulating sphingolipids are associated with poor outcomes in patients with mCRPC, including therapeutic resistance and shorter overall survival. PCPro is a clinically accessible, regulatory compliant plasma lipid biomarker of poor prognosis in mCRPC, which incorporates prognostic sphingolipids. We hypothesize that reversal of the PCPro signature in men with mCRPC by sphingolipid-lowering agents will improve their clinical outcomes. However, the first step is to determine whether this poor prognostic lipid signature can be modulated. A potential sphingolipid-lowering agent is the PCSK9-inhibitor evolocumab, which is used in the management of hypercholesterolemia.

Objectives

Our primary objective is to assess whether treatment with evolocumab during standard anticancer therapy can safely modify the PCPro signature in men with mCRPC.

Design

This is a multicenter, open label phase II trial.

Methods

Men with mCRPC commencing docetaxel, cabazitaxel, abiraterone, enzalutamide, olaparib, or lutetium-177 PSMA for disease progression will be screened for the presence of PCPro. Those who are PCPro positive will receive a 12-week course of evolocumab concurrent with their standard therapy. Dosage is as per cardiovascular guidelines (420 mg subcutaneously every 4 weeks). PCPro will be repeated after 12 weeks. The primary endpoint is reversal of PCPro. The secondary endpoint is the safety of combination therapy with exploratory endpoints characterizing changes in comprehensive lipid profiles pre- and post-treatment.

Discussion

This study will evaluate whether evolocumab can safely modify the PCPro signature in men with mCRPC, providing essential data to the development of precision metabolic therapy in the management of prostate cancer.

Trial registration

This study is approved by the Human Research Ethics Committee (X22-0072 and 2022/ETH00427). It is registered with the Australian New Zealand Clinical Trials Registry (ACTRN12622001003763).

Effect of diet and genotype on the lipidome of mice with altered lipoprotein metabolism

The present study describes and compares the impact of PCSK9 and LDLR, two pivotal players in cholesterol metabolism, on the whole lipidome of plasma, liver and aorta in different dietary conditions. This issue is relevant, since several lipid species, circulating at very low concentrations, have the ability to impair lipid metabolism and promote atherosclerosis development. To this aim, wild-type, hypercholesterolemic Ldlr-KO, and hypocholesterolemic Pcsk9-KO mice were fed a standard chow or a Western-type diet up to 30 and 16 weeks of age, respectively. 42 lipids including cholesterol, cholesteryl esters, several sphingolipids, phospholipids, and lysophospholipids, accumulated uniquely in the atherosclerotic aorta of Western-type diet-fed Ldlr-KO mice. In addition, multiple organ/tissue comparisons allowed us to identify 16 lipids whose plasma and hepatic patterns mirrored the lipidome of the atherosclerotic aorta. These lipid species, belonging to cholesteryl esters, glucosyl/galactosylceramide, lactosylceramide, globotriaosylceramide, sphingomyelin, and phosphatidylcholine could be further investigated as circulating biomarkers or therapeutic targets.

Circulating Lipid Profiles Associated With Resistance to Androgen Deprivation Therapy in Localized Prostate Cancer

PURPOSE

Intense androgen deprivation therapy (ADT) with androgen receptor pathway inhibitors (ARPIs) before radical prostatectomy (RP) produced favorable pathologic responses in approximately 20% of patients. The molecular reason for the low rate of response remains unclear. Lipid metabolism is known to influence androgen receptor signaling and ARPI efficacy. The aim of the study was to identify circulating lipid profiles associated with ADT/ARPI resistance in localized prostate cancer.

MATERIALS AND METHODS

Two independent experimental approaches were used. Experiment 1: Post hoc analysis of the association between plasma lipidomic profiles and ADT/ARPI response was performed on patients (n = 104) from two phase II trials of neoadjuvant ADT/ARPI. Response to ADT/ARPI was defined by pathologic response. Experiment 2: Patient-derived tumor explants from RP (n = 105) were cultured in enzalutamide for 48 hours. Explant response to enzalutamide was evaluated against pre-RP plasma lipidomic profiles (n = 105) and prostate tissue lipidomic profiles (n = 36). Response was defined by Ki67 (cell proliferation marker) fold difference between enzalutamide and vehicle-treated explants. In both experiments, associations between lipid profiles and ADT/ARPI response were analyzed by latent class analysis.

RESULTS

Pretreatment plasma lipid profiles classified each experimental cohort into two groups with differences in ADT/ARPI response rates. The response rates of the groups were 9.6% versus 29% in experiment 1 (chi-squared test P = .012) and 49% versus 70% in experiment 2 (chi-squared test P = .037). In both experiments, the group with a higher incidence of ADT/ARPI resistance had higher plasma levels of sphingomyelin, glycosylceramides, free fatty acids, acylcarnitines, cholesterol esters, and alkyl/alkenyl-phosphatidylcholine and lower plasma levels of triacylglycerols, diacylglycerols, and phosphoethanolamine (t-test P < .05).

CONCLUSION

Pretreatment circulating lipid profiles are associated with ADT/ARPI resistance in localized cancer in both human cohorts and explant models.

Mechanisms modulating foam cell formation in the arterial intima: exploring new therapeutic opportunities in atherosclerosis

In recent years, the role of macrophages as the primary cell type contributing to foam cell formation and atheroma plaque development has been widely acknowledged. However, it has been long recognized that diffuse intimal thickening (DIM), which precedes the formation of early fatty streaks in humans, primarily consists of lipid-loaded smooth muscle cells (SMCs) and their secreted proteoglycans. Recent studies have further supported the notion that SMCs constitute the majority of foam cells in advanced atherosclerotic plaques. Given that SMCs are a major component of the vascular wall, they serve as a significant source of microvesicles and exosomes, which have the potential to regulate the physiology of other vascular cells. Notably, more than half of the foam cells present in atherosclerotic lesions are of SMC origin. In this review, we describe several mechanisms underlying the formation of intimal foam-like cells in atherosclerotic plaques. Based on these mechanisms, we discuss novel therapeutic approaches that have been developed to regulate the generation of intimal foam-like cells. These innovative strategies hold promise for improving the management of atherosclerosis in the near future.

Association of cardiac biomarkers with long-term cardiovascular events in a community cohort

MATERIALS AND METHODS

The study assessed major adverse cardiac events (MACE) (myocardial infarction, coronary artery bypass graft, percutaneous intervention, stroke, and death. Cox proportional hazards models assessed apolipoprotein AI (ApoA1), apolipoprotein B (ApoB), ceramide score, cystatin C, galectin-3 (Gal3), LDL-C, Non-HDL-C, total cholesterol (TC), N-terminal B-type natriuretic peptide (NT proBNP), high-sensitivity cardiac troponin (HscTnI) and soluble interleukin 1 receptor-like 1. In adjusted models, Ceramide score was defined by from N-palmitoyl-sphingosine [Cer(16:0)], N-stearoyl-sphingosine [Cer(18:0)], N-nervonoyl-sphingosine [Cer(24:1)] and N-lignoceroyl-sphingosine [Cer(24:0)]. Multi-biomarker models were compared with C-statistics and Integrated Discrimination Index (IDI).

RESULTS

A total of 1131 patients were included. Adjusted NT proBNP per 1 SD resulted in a 31% increased risk of MACE/death (HR = 1.31) and a 31% increased risk for stroke/MI (HR = 1.31). Adjusted Ceramide per 1 SD showed a 13% increased risk of MACE/death (HR = 1.13) and a 29% increased risk for stroke/MI (HR = 1.29). These markers added to clinical factors for both MACE/death (p = 0.003) and stroke/MI (p = 0.034). HscTnI was not a predictor of outcomes when added to the models.

DISCUSSION

Ceramide score and NT proBNP improve the prediction of MACE and stroke/MI in a community primary prevention cohort.

Remnant Cholesterol, Not LDL Cholesterol, Explains Peripheral Artery Disease Risk Conferred by apoB: A Cohort Study

BACKGROUND

Elevated apoB-containing lipoproteins (=remnants+LDLs [low-density lipoproteins]) are a major risk factor for atherosclerotic cardiovascular disease, including peripheral artery disease (PAD) and myocardial infarction. We tested the hypothesis that remnants and LDL both explain part of the increased risk of PAD conferred by elevated apoB-containing lipoproteins. For comparison, we also studied the risk of chronic limb-threatening ischemia and myocardial infarction.

METHODS

apoB, remnant cholesterol, and LDL cholesterol were measured in 93 461 individuals without statin use at baseline from the Copenhagen General Population Study (2003-2015). During up to 15 years of follow-up, 1207 had PAD, 552 had chronic limb-threatening ischemia, and 2022 had myocardial infarction in the Danish National Patient Registry. Remnant and LDL cholesterol were calculated from a standard lipid profile. Remnant and LDL particle counts were additionally measured with nuclear magnetic resonance spectroscopy in 25 347 of the individuals. Results were replicated in 302 167 individuals without statin use from the UK Biobank (2004-2010).

RESULTS

In the Copenhagen General Population Study, multivariable adjusted hazard ratios for risk of PAD per 1 mmol/L (39 mg/dL) increment in remnant and LDL cholesterol were 1.9 (95% CI, 1.5-2.4) and 1.1 (95% CI, 1.0-1.2), respectively; corresponding results in the UK Biobank were 1.7 (95% CI, 1.4-2.1) and 0.9 (95% CI, 0.9-1.0), respectively. In the association from elevated apoB to increased risk of PAD, remnant and LDL cholesterol explained 73% (32%-100%) and 8% (0%-46%), respectively; corresponding results were 63% (30%-100%) and 0% (0%-33%) for risk of chronic limb-threatening ischemia and 41% (27%-55%) and 54% (38%-70%) for risk of myocardial infarction; results for remnant and LDL particle counts corroborated these findings.

CONCLUSIONS

PAD risk conferred by elevated apoB-containing lipoproteins was explained mainly by elevated remnants, while myocardial infarction risk was explained by both elevated remnants and LDL.

Vitamin D and Ceramide Metabolomic Profile in Acute Myocardial Infarction

Sphingolipids (SLs) influence several cellular pathways, while vitamin D exerts many extraskeletal effects in addition to its traditional biological functions, including the modulation of calcium homeostasis and bone health. Moreover, Vitamin D and SLs affect the regulation of each others' metabolism; hence, this study aims to evaluate the relationship between the levels of 25(OH)D and ceramides in acute myocardial infarction (AMI). In particular, the blood abundance of eight ceramides and 25(OH)D was evaluated in 134 AMI patients (aged 68.4 ± 12.0 years, 72% males). A significant inverse correlation between 25(OH)D and both Cer(d18:1/16:0) and Cer(d18:1/18:0) was found; indeed, patients with severe hypovitaminosis D (<10 ng/mL) showed the highest levels of the two investigated ceramides. Moreover, diabetic/dyslipidemic patients with suboptimal levels of 25(OH)D (<30 ng/mL) had higher levels of both the ceramides when compared with the rest of the population. On the other hand, 25(OH)D remained an independent determinant for Cer(d18:1/16:0) (STD Coeff -0.18, t-Value -2, p ≤ 0.05) and Cer(d18:1/18:0) (-0.2, -2.2, p < 0.05). In light of these findings, the crosstalk between sphingolipids and vitamin D may unravel additional mechanisms by which these molecules can influence CV risk in AMI.

Perspectives on the success of plasma lipidomics in cardiovascular drug discovery and future challenges

INTRODUCTION

Plasma lipidomics has emerged as a powerful tool in cardiovascular drug discovery by providing insights into disease mechanisms, identifying potential biomarkers for diagnosis and prognosis, and discovering novel targets for drug development. Widespread application of plasma lipidomics is hampered by technological limitations and standardization and requires a collaborative approach to maximize its use in cardiovascular drug discovery.

AREAS COVERED

This review provides an overview of the utility of plasma lipidomics in cardiovascular drug discovery and discusses the challenges and future perspectives of this rapidly evolving field. The authors discuss the role of lipidomics in understanding the molecular mechanisms of CVD, identifying novel biomarkers for diagnosis and prognosis, and discovering new therapeutic targets for drug development. Furthermore, they highlight the challenges faced in data analysis, standardization, and integration with other omics approaches and propose future directions for the field.

EXPERT OPINION

Plasma lipidomics holds great promise for improving the diagnosis, treatment, and prevention of CVD. While challenges remain in standardization and technology, ongoing research and collaboration among scientists and clinicians will undoubtedly help overcome these obstacles. As lipidomics evolves, its impact on cardiovascular drug discovery and clinical practice is expected to grow, ultimately benefiting patients and healthcare systems worldwide.

Role of proprotein convertase subtilisin/kexin type 9 (PCSK9) in diabetic complications

Cardiovascular disease (CVD) complications have remained a major cause of death among patients with diabetes. Hence, there is a need for effective therapeutics against diabetes-induced CVD complications. Since its discovery, proprotein convertase subtilisin/kexin type 9 (PCSK9) has been reported to be involved in the pathology of various CVDs, with studies showing a positive association between plasma levels of PCSK9, hyperglycemia, and dyslipidemia. PCSK9 regulates lipid homeostasis by interacting with low-density lipoprotein receptors (LDLRs) present in hepatocytes and subsequently induces LDLR degradation via receptor-mediated endocytosis, thereby reducing LDL uptake from circulation. In addition, PCSK9 also induces pro-inflammatory cytokine expression and apoptotic cell death in diabetic-CVD. Furthermore, therapies designed to inhibit PCSK9 effectively reduces diabetic dyslipidemia with clinical studies reporting reduced cardiovascular events in patients with diabetes and no significant adverse effect on glycemic controls. In this review, we discuss the role of PCSK9 in the pathogenesis of diabetes-induced CVD and the potential mechanisms by which PCSK9 inhibition reduces cardiovascular events in diabetic patients.

Ceramides improve cardiovascular risk prediction beyond low-density lipoprotein cholesterol

Aims

Low-density lipoprotein cholesterol (LDL-C) is the best documented cardiovascular risk predictor and at the same time serves as a target for lipid-lowering therapy. However, the power of LDL-C to predict risk is biased by advanced age, comorbidities, and medical treatment, all known to impact cholesterol levels. Consequently, such biased patient cohorts often feature a U-shaped or inverse association between LDL-C and cardiovascular or overall mortality. It is not clear whether these constraints for risk prediction may likewise apply to other lipid risk markers in particular to ceramides and phosphatidylcholines.

Methods and results

In this observational cohort study, we recorded cardiovascular mortality in 1195 patients over a period of up to 16 years, comprising a total of 12 262 patient-years. The median age of patients at baseline was 67 years. All participants were either consecutively referred to elective coronary angiography or diagnosed with peripheral artery disease, indicating a high cardiovascular risk. At baseline, 51% of the patients were under statin therapy. We found a U-shaped association between LDL-C and cardiovascular mortality with a trough level of around 150 mg/dL of LDL-C. Cox regression analyses revealed that LDL-C and other cholesterol species failed to predict cardiovascular risk. In contrast, no U-shaped but linear association was found for ceramide- and phosphatidylcholine-containing markers and these markers were able to significantly predict the cardiovascular risk even after multivariate adjustment.

Conclusion

We thus suggest that ceramides- and phosphatidylcholine-based predictors rather than LDL-C may be used for a more accurate cardiovascular risk prediction in high-risk patients.

Do Triglyceride-Rich Lipoproteins Equal Low-Density Lipoproteins in Risk of ASCVD?

PURPOSE OF REVIEW

Recent large clinical trials have failed to show that triglyceride-rich lipoprotein-lowering therapies decrease the risk of atherosclerotic cardiovascular disease (ASCVD). In this review, we reconcile these findings with evidence showing that elevated levels of triglyceride-rich lipoproteins and the cholesterol they contain, remnant cholesterol, cause ASCVD alongside low-density lipoprotein (LDL) cholesterol.

RECENT FINDINGS

Results from observational epidemiology, genetic epidemiology, and randomized controlled trials indicate that lowering of remnant cholesterol and LDL cholesterol decrease ASCVD risk by a similar magnitude per 1 mmol/L (39 mg/dL) lower non-high-density lipoprotein cholesterol (remnant cholesterol+LDL cholesterol). Indeed, recent guidelines for ASCVD prevention recommend the use of non-high-density lipoprotein cholesterol instead of LDL cholesterol. Current consensus is moving towards recognizing remnant cholesterol and LDL cholesterols as equals per 1 mmol/L (39 mg/dL) higher levels in the risk assessment of ASCVD; hence, triglyceride-rich lipoprotein-lowering therapies should also lower levels of non-HDL cholesterol to reduce ASCVD risk.

Untargeted lipidomics reveal association of elevated plasma C18 ceramide levels with reduced survival in metastatic castration-resistant prostate cancer patients

Emerging evidence highlights the potential prognostic relevance of circulating lipids in metastatic castration-resistant prostate cancer (mCRPC), with a proposed 3-lipid signature. This study aims to analyze the lipidomic profiles of individuals with mCRPC to identify lipid species that could serve as predictive indicators of prognosis and therapeutic response. Plasma samples were collected from mCRPC patients initiating first-line treatment (1 L) (n = 29) and those previously treated with at least two lines of therapy (> 2 L) (n = 19), including an androgen-receptor signaling inhibitor and a taxane. Employing an untargeted lipidomic approach, lipids were extracted from the plasma samples and subjected to analysis. A comprehensive identification and quantification of 789 plasma lipids was achieved. Notably, 75 species displayed significant dysregulation in > 2 L patients in comparison to the 1 L group. Among these, 63 species exhibited elevated levels, while 12 were reduced. Patients included in > 2 L cohort showed elevated levels of acylcarnitines (CAR), diacylglycerols (DG), phosphatidylethanolamines (PE), triacylglycerols (TG), and ceramides (Cer). Notably, some upregulated lipids, including CAR 14:0, CAR 24:1, Cer d18:1/16:0, Cer d18:1/18:0 (C18 Cer), Cer d18:2/18:0, Cer d18:1/24:1, and Cer d20:1/24:1, showed significant associations with overall survival (OS) in univariate models. Specifically, increased levels of C18 Cer remained significantly associated with poorer OS in the multivariate model, even after adjusting for treatment line and PSA levels (Hazard Ratio: 3.59 [95% Confidence Interval 1.51-8.52], p = 0.004). Employing quantitative mass spectrometry, our findings underscore the independent prognostic significance of C18 Cer in individuals with mCRPC. This discovery opens avenues for further studies within this field.

Coronary Event Risk Test (CERT) as a Risk Predictor for the 10-Year Clinical Outcome of Patients with Peripheral Artery Disease

(1) Background: Ceramides are a new kind of lipid biomarker and have already been demonstrated to be valuable risk predictors in coronary patients. Patients with peripheral artery disease (PAD) are a population with a worse prognosis and higher mortality risk compared to coronary artery disease (CAD) patients. However, the value of ceramides for risk prediction in PAD patients is still vague, as addressed in the present study. (2)Methods: This observational study included 379 PAD patients. The primary endpoint was all-cause mortality at 10 years of follow-up. A set of ceramides was measured by LC-MS/MS and combined according to the Coronary Event Risk Test (CERT) score, which categorizes patients into one of four risk groups (low risk, moderate risk, high risk, very high risk). (3) Results: Kaplan-Meier survival curves revealed that the overall survival of patients decreased with the increasing risk predicted by the four CERT categories, advancing from low risk to very high risk. Cox regression analysis demonstrated that each one-category increase resulted in a 35% rise in overall mortality risk (HR = 1.35 [1.16-1.58]). Multivariable adjustment, including, among others, age, LDL-cholesterol, type 2 diabetes, and statin treatment before the baseline, did not abrogate this significant association (HR = 1.22 [1.04-1.43]). Moreover, we found that the beneficial effect of statin treatment is significantly stronger in patients with a higher risk, according to CERT. (4) Conclusions: We conclude that the ceramide-based risk score CERT is a strong predictor of the 10-year mortality risk in patients with PAD.

Integrated omics approach for the identification of HDL structure-function relationships in PCSK9-related familial hypercholesterolemia

BACKGROUND

The role of proprotein convertase subtilisin/kexin type 9 (PCSK9) in dyslipidemia may go beyond its immediate effects on low-density lipoprotein receptor (LDL-R) activity.

OBJECTIVE

This study aimed to assess PCSK9-derived alterations of high-density lipoprotein (HDL) physiology, which bear a potential to contribute to cardiovascular risk profile.

METHODS

HDL was isolated from 33 patients with familial autosomal dominant hypercholesterolemia (FH), including those carrying PCSK9 gain-of-function (GOF) genetic variants (FH-PCSK9, n = 11), together with two groups of dyslipidemic patients employed as controls and carrying genetic variants in the LDL-R not treated (ntFH-LDLR, n = 11) and treated (tFH-LDLR, n = 11) with statins, and 11 normolipidemic controls. Biological evaluations paralleled by proteomic, lipidomic and glycomic analyses were applied to characterize functional and compositional properties of HDL.

RESULTS

Multiple deficiencies in the HDL function were identified in the FH-PCSK9 group relative to dyslipidemic FH-LDLR patients and normolipidemic controls, which involved reduced antioxidative, antiapoptotic, anti-thrombotic and anti-inflammatory activities. By contrast, cellular cholesterol efflux capacity of HDL was unchanged. In addition, multiple alterations of the proteomic, lipidomic and glycomic composition of HDL were found in the FH-PCSK9 group. Remarkably, HDLs from FH-PCSK9 patients were systematically enriched in several lysophospholipids as well as in A2G2S2 (GP13) glycan and apolipoprotein A-IV. Based on network analysis of functional and compositional data, a novel mosaic structure-function model of HDL biology involving FH was developed.

CONCLUSION

Several metrics of anti-atherogenic HDL functionality are altered in FH-PCSK9 patients paralleled by distinct compositional alterations. These data provide a first-ever overview of the impact of GOF PCSK9 genetic variants on structure-function relationships in HDL.

Proteomics and Lipidomics to unveil the contribution of PCSK9 beyond cholesterol lowering: a narrative review

Proprotein convertase subtilisin/kexin type 9 (PCSK9), one of the key regulators of the low-density lipoprotein receptor (LDLR), can play a direct role in atheroma development. Although advances in the understandings of genetic PCSK9 polymorphisms have enabled to reveal the role of PCSK9 in the complex pathophysiology of cardiovascular diseases (CVDs), increasing lines of evidence support non-cholesterol-related processes mediated by PCSK9. Owing to major improvements in mass spectrometry-based technologies, multimarker proteomic and lipidomic panels hold the promise to identify novel lipids and proteins potentially related to PCSK9. Within this context, this narrative review aims to provide an overview of the most significant proteomics and lipidomics studies related to PCSK9 effects beyond cholesterol lowering. These approaches have enabled to unveil non-common targets of PCSK9, potentially leading to the development of novel statistical models for CVD risk prediction. Finally, in the era of precision medicine, we have reported the impact of PCSK9 on extracellular vesicles (EVs) composition, an effect that could contribute to an increased prothrombotic status in CVD patients. The possibility to modulate EVs release and cargo could help counteract the development and progression of the atherosclerotic process.

PCSK9 deficiency alters brain lipid composition without affecting brain development and function

PCSK9 induces lysosomal degradation of the low-density lipoprotein (LDL) receptor (LDLR) in the liver, hereby preventing removal of LDL cholesterol from the circulation. Accordingly, PCSK9 inhibitory antibodies and siRNA potently reduce LDL cholesterol to unprecedented low levels and are approved for treatment of hypercholesterolemia. In addition, PCSK9 inactivation alters the levels of several other circulating lipid classes and species. Brain function is critically influenced by cholesterol and lipid composition. However, it remains unclear how the brain is affected long-term by the reduction in circulating lipids as achieved with potent lipid lowering therapeutics such as PCSK9 inhibitors. Furthermore, it is unknown if locally expressed PCSK9 affects neuronal circuits through regulation of receptor levels. We have studied the effect of lifelong low peripheral cholesterol levels on brain lipid composition and behavior in adult PCSK9 KO mice. In addition, we studied the effect of PCSK9 on neurons in culture and in vivo in the developing cerebral cortex. We found that PCSK9 reduced LDLR and neurite complexity in cultured neurons, but neither PCSK9 KO nor overexpression affected cortical development in vivo. Interestingly, PCSK9 deficiency resulted in changes of several lipid classes in the adult cortex and cerebellum. Despite the observed changes, PCSK9 KO mice had unchanged behavior compared to WT controls. In conclusion, our findings demonstrate that altered PCSK9 levels do not compromise brain development or function in mice, and are in line with clinical trials showing that PCSK9 inhibitors have no adverse effects on cognitive function.

The Dark Side of Sphingolipids: Searching for Potential Cardiovascular Biomarkers

Cardiovascular diseases (CVDs) are the leading cause of death and illness in Europe and worldwide, responsible for a staggering 47% of deaths in Europe. Over the past few years, there has been increasing evidence pointing to bioactive sphingolipids as drivers of CVDs. Among them, most studies place emphasis on the cardiovascular effect of ceramides and sphingosine-1-phosphate (S1P), reporting correlation between their aberrant expression and CVD risk factors. In experimental in vivo models, pharmacological inhibition of de novo ceramide synthesis averts the development of diabetes, atherosclerosis, hypertension and heart failure. In humans, levels of circulating sphingolipids have been suggested as prognostic indicators for a broad spectrum of diseases. This article provides a comprehensive review of sphingolipids' contribution to cardiovascular, cerebrovascular and metabolic diseases, focusing on the latest experimental and clinical findings. Cumulatively, these studies indicate that monitoring sphingolipid level alterations could allow for better assessment of cardiovascular disease progression and/or severity, and also suggest them as a potential target for future therapeutic intervention. Some approaches may include the down-regulation of specific sphingolipid species levels in the circulation, by inhibiting critical enzymes that catalyze ceramide metabolism, such as ceramidases, sphingomyelinases and sphingosine kinases. Therefore, manipulation of the sphingolipid pathway may be a promising strategy for the treatment of cardio- and cerebrovascular diseases.

Type 2 Diabetes mellitus alters the cargo of (poly)phenol metabolome and the oxidative status in circulating lipoproteins

The incidence of diabetes on the worldwide population has tripled in the past 5 decades. While drug-based therapies are valuable strategies to treat and ease the socio-economic burden of diabetes, nutritional strategies offer valuable alternatives to prevent and manage diabetes onset and contribute to the sustainability of health budgets. Whilst, intervention studies have shown that (poly)phenol-rich diets improve fasting glucose levels and other blood parameters, very little is known about the distribution of ingested polyphenols in circulation and the impact of diabetes on its cargo. In this study we investigate the impact of type 2 diabetes on the cargo of plasma (poly)phenols. Our results show that phenolic compounds are heterogeneously distributed in circulation though mainly transported by lipoprotein populations. We also found that diabetes has a marked effect on the phenolic content transported by VLDL resulting in the decrease in the content of flavonoids and consequently a decrease in the antioxidant capacity. In addition to the reduced bioavailability of (poly)phenol metabolites and increase of oxidative status in LDL and HDL populations in diabetes, cell-based assays show that sub-micromolar amounts of microbial (poly)phenol metabolites are able to counteract the pro-inflammatory status in glucose-challenged endothelial cells. Our findings highlight the relevance of triglyceride-rich lipoproteins in the transport and delivery of bioactive plant-based compounds to the endothelium in T2DM supporting the adoption of nutritional guidelines as an alternative strategy to drug-based therapeutic approaches.

Modulation of Plasma Lipidomic Profiles in Metastatic Castration-Resistant Prostate Cancer by Simvastatin

Elevated circulating sphingolipids are associated with shorter overall survival and therapeutic resistance in metastatic castration-resistant prostate cancer (mCRPC), suggesting that perturbations in sphingolipid metabolism promotes prostate cancer growth. This study assessed whether addition of simvastatin to standard treatment for mCRPC can modify a poor prognostic circulating lipidomic profile represented by a validated 3-lipid signature (3LS). Men with mCRPC (n = 27) who were not on a lipid-lowering agent, were given simvastatin for 12 weeks (40 mg orally, once daily) with commencement of standard treatment. Lipidomic profiling was performed on their plasma sampled at baseline and after 12 weeks of treatment. Only 11 men had the poor prognostic 3LS at baseline, of whom five (45%) did not retain the 3LS after simvastatin treatment (expected conversion rate with standard treatment = 19%). At baseline, the plasma profiles of men with the 3LS displayed higher levels (p < 0.05) of sphingolipids (ceramides, hexosylceramides and sphingomyelins) than those of men without the 3LS. These plasma sphingolipids were reduced after statin treatment in men who lost the 3LS (mean decrease: 23−52%, p < 0.05), but not in men with persistent 3LS, and were independent of changes to plasma cholesterol, LDL-C or triacylglycerol. In conclusion, simvastatin in addition to standard treatment can modify the poor prognostic circulating lipidomic profile in mCRPC into a more favourable profile at twice the expected conversion rate.

Ceramide Metabolism in Cardiovascular Disease: A Network With High Therapeutic Potential

Growing evidence suggests that ceramides play an important role in the development of atherosclerotic and valvular heart disease. Ceramides are biologically active sphingolipids that are produced by a complex network of enzymes. Lowering cellular and tissue levels of ceramide by inhibiting the ceramide-producing enzymes counteracts atherosclerotic and valvular heart disease development in animal models. In vascular tissues, ceramides are produced in response to hyperglycemia and TNF (tumor necrosis factor)-α signaling and are involved in NO-signaling and inflammation. In humans, elevated blood ceramide levels are associated with cardiovascular events. Furthermore, important cardiovascular risk factors, such as obesity and diabetes, have been linked to ceramide accumulation. This review summarizes the basic mechanisms of how ceramides drive cardiovascular disease locally and links these findings to the intriguing results of human studies on ceramides as biomarkers for cardiovascular events. Moreover, we discuss the current state of interventions to therapeutically influence vascular ceramide metabolism, both locally and systemically.

Antitumor activity and molecular mechanism of proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibition

Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a member of the proprotein convertase family of proteins that activate other proteins in cells. Functionally, PCSK9 binds to the receptor of low-density lipoprotein particles (LDL) to regulate cholesterol metabolism and lipoprotein homeostasis in human body. PCSK9 inhibition is a novel pharmacological strategy to control hypercholesterolemia and cardiovascular diseases. Recently accumulating evidence realizes that PCSK9 possesses other roles in cells, such as regulation of tissue inflammatory response, intratumoral immune cell infiltration, and tumor progression. This review discussed the advancement of PCSK9 research on its role and underlying mechanisms in tumor development and progression. For example, PCSK9 inhibition could attenuate progression of breast cancer, glioma, colon tumor, hepatocellular cancer, prostate cancer, and lung adenocarcinoma and promote apoptosis of glioma, prostate cancer, and hepatocellular cancer cells. PCSK9 deficiency could reduce liver metastasis of B16F1 melanoma cells by lowering the circulating cholesterol levels. PCSK9 gene knockdown substantially attenuated mouse tumor growth in vivo by activation of cytotoxic T cells, although PCSK9 knockdown had no effect on morphology and growth rate of different mouse cancer cell lines in vitro. PCSK9 inhibition thus can be used to control human cancers. Future preclinical and clinical studies are warranted to define anti-tumor activity of PCSK9 inhibition.

Ceramides and phospholipids in plasma extracellular vesicles are associated with high risk of major cardiovascular events after carotid endarterectomy

Ceramides and phosphatidylcholines (PCs) are bioactive lipids and lipid bilayer membrane components. Distinct ceramides/PCs (ratios) predict cardiovascular outcome in patients with coronary artery disease. Extracellular vesicles (EVs) are proposed biomarkers for cardiovascular disease and contain ceramides/PCs. Ceramides/PCs have not been studied in patients undergoing carotid endarterectomy (CEA) nor in EVs. We therefore investigated whether levels of ceramides/PCs in plasma and EVs are associated with postoperative risk of major adverse cardiovascular events (MACE) following CEA. In 873 patients undergoing CEA of the Athero-Express biobank, we quantitatively measured seven ceramides/PCs in preoperative blood samples: Cer(d18:1/16:0), Cer(d18:1/18:0), Cer(d18:1/24:0), Cer(d18:1/24:1), PC(14:0/22:6), PC(16:0/16:0) and PC(16:0/22:5) in plasma and two plasma EV-subfractions (LDL and TEX). We analyzed the association of ceramides, PCs and their predefined ratios with the three-year postoperative risk of MACE (including stroke, myocardial infarction and cardiovascular death). A total of 138 patients (16%) developed MACE during the three-year follow-up. In the LDL-EV subfraction, higher levels of Cer(d18:1/24:1) and Cer(d18:1/16:0)/PC(16:0/22:5) ratio were significantly associated with an increased risk of MACE (adjusted HR per SD [95% CI] 1.24 [1.01–1.53] and 1.26 [1.04–1.52], respectively). In the TEX-EV subfraction, three ratios Cer(d18:1/16:0)/Cer(d18:1/24:0), Cer(d18:1/18:0)/Cer(d18:1/24:0) and Cer(d18:1/24:1)/Cer(d18:1/24:0) were positively associated with MACE (adjusted HR per SD 1.34 [1.06–1.70], 1.24 [1.01–1.51] and 1.31 [1.08–1.58], respectively). In conclusion, distinct ceramides and PCs in plasma EVs determined in preoperative blood were independently associated with an increased 3-year risk of MACE after CEA. These lipids are therefore potential markers to identify high-risk CEA patients qualifying for secondary preventive add-on therapy.

Combined impact of lipidomic and genetic aberrations on clinical outcomes in metastatic castration-resistant prostate cancer

BACKGROUND

Both changes in circulating lipids represented by a validated poor prognostic 3-lipid signature (3LS) and somatic tumour genetic aberrations are individually associated with worse clinical outcomes in men with metastatic castration-resistant prostate cancer (mCRPC). A key question is how the lipid environment and the cancer genome are interrelated in order to exploit this therapeutically. We assessed the association between the poor prognostic 3-lipid signature (3LS), somatic genetic aberrations and clinical outcomes in mCRPC.

METHODS

We performed plasma lipidomic analysis and cell-free DNA (cfDNA) sequencing on 106 men with mCRPC commencing docetaxel, cabazitaxel, abiraterone or enzalutamide (discovery cohort) and 94 men with mCRPC commencing docetaxel (validation cohort). Differences in lipid levels between men ± somatic genetic aberrations were assessed with t-tests. Associations between the 3LS and genetic aberrations with overall survival (OS) were examined using Kaplan-Meier methods and Cox proportional hazard models.

RESULTS

The 3LS was associated with shorter OS in the discovery (hazard ratio [HR] 2.15, 95% confidence interval [CI] 1.4-3.3, p < 0.001) and validation cohorts (HR 2.32, 95% CI 1.59-3.38, p < 0.001). Elevated plasma sphingolipids were associated with AR, TP53, RB1 and PI3K aberrations (p < 0.05). Men with both the 3LS and aberrations in AR, TP53, RB1 or PI3K had shorter OS than men with neither in both cohorts (p ≤ 0.001). The presence of 3LS and/or genetic aberration was independently associated with shorter OS for men with AR, TP53, RB1 and PI3K aberrations (p < 0.02). Furthermore, aggressive-variant prostate cancer (AVPC), defined as 2 or more aberrations in TP53, RB1 and/or PTEN, was associated with elevated sphingolipids. The combination of AVPC and 3LS predicted for a median survival of ~12 months. The relatively small sample size of the cohorts limits clinical applicability and warrants future studies.

CONCLUSIONS

Elevated circulating sphingolipids were associated with AR, TP53, RB1, PI3K and AVPC aberrations in mCRPC, and the combination of lipid and genetic abnormalities conferred a worse prognosis. These findings suggest that certain genotypes in mCRPC may benefit from metabolic therapies.

Emerging Insights on the Diverse Roles of Proprotein Convertase Subtilisin/Kexin Type 9 (PCSK9) in Chronic Liver Diseases: Cholesterol Metabolism and Beyond

Chronic liver diseases are commonly associated with dysregulated cholesterol metabolism. Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a serine protease of the proprotein convertase family that is mainly synthetized and secreted by the liver, and represents one of the key regulators of circulating low-density lipoprotein (LDL) cholesterol levels. Its ability to bind and induce LDL-receptor degradation, in particular in the liver, increases circulating LDL-cholesterol levels in the blood. Hence, inhibition of PCSK9 has become a very potent tool for the treatment of hypercholesterolemia. Besides PCSK9 limiting entry of LDL-derived cholesterol, affecting multiple cholesterol-related functions in cells, more recent studies have associated PCSK9 with various other cellular processes, including inflammation, fatty acid metabolism, cancerogenesis and visceral adiposity. It is increasingly becoming evident that additional roles for PCSK9 beyond cholesterol homeostasis are crucial for liver physiology in health and disease, often contributing to pathophysiology. This review will summarize studies analyzing circulating and hepatic PCSK9 levels in patients with chronic liver diseases. The factors affecting PCSK9 levels in the circulation and in hepatocytes, clinically relevant studies and the pathophysiological role of PCSK9 in chronic liver injury are discussed.

An Untargeted Lipidomic Analysis Reveals Depletion of Several Phospholipid Classes in Patients with Familial Hypercholesterolemia on Treatment with Evolocumab

Rationale: Familial hypercholesterolemia (FH) is caused by mutations in genes involved in low-density lipoprotein cholesterol (LDL-C) metabolism, including those for pro-protein convertase subtilisin/kexin type 9 (PCSK-9). The effect of PCSK-9 inhibition on the plasma lipidome has been poorly explored. Objective: Using an ultra-high-performance liquid chromatography-electrospray ionization-quadrupole-time of flight-mass spectrometry method, the plasma lipidome of FH subjects before and at different time intervals during treatment with the PCSK-9 inhibitor Evolocumab was explored. Methods and Results: In 25 FH subjects, heterozygotes or compound heterozygotes for different LDL receptor mutations, untargeted lipidomic revealed significant reductions in 26 lipid classes belonging to phosphatidylcholine (PC), sphingomyelin (SM), ceramide (CER), cholesteryl ester (CE), triacylglycerol (TG) and phosphatidylinositol (PI). Lipid changes were graded between baseline and 4- and 12-week treatment. At 12-week treatment, five polyunsaturated diacyl PC, accounting for 38.6 to 49.2% of total PC at baseline; two ether/vinyl ether forms; seven SM; five CER and glucosyl/galactosyl-ceramide (HEX-CER) were reduced, as was the unsaturation index of HEX-CER and lactosyl—CER (LAC-CER). Although non quantitative modifications were observed in phosphatidylethanolamine (PE) during treatment with Evolocumab, shorter and more saturated fatty acyl chains were documented. Conclusions: Depletion of several phospholipid classes occurs in plasma of FH patients during treatment with the PCSK-9 inhibitor Evolocumab. The mechanism underlying these changes likely involves the de novo synthesis of SM and CER through the activation of the key enzyme sphingomyelin synthase by oxidized LDL and argues for a multifaceted system leading to vascular improvement in users of PCSK-9 inhibitors.

Lipid profiles of patients with manifest coronary versus peripheral atherosclerosis - Is there a difference?

AIM

Peripheral arterial disease (PAD) and coronary artery disease (CAD) are both caused by atherosclerosis. Serum lipids and lipoproteins are predictive of the development of atherosclerosis but it is not clear if they differ in the two manifestations, PAD and CAD. We tested whether a more detailed characterization of the lipid and lipoprotein patterns of PAD and CAD allows a clear differentiation between the two atherosclerotic phenotypes.

METHODS

A cohort of 274 statin-naïve patients with either newly diagnosed imaging proven PAD (n = 89) or stable CAD (n = 185) was characterized using nuclear magnetic resonance- and liquid chromatography-tandem mass spectrometry-based advanced lipid and lipoprotein analysis. An independent cohort of 1239 patients with PAD and CAD was used for validation.

RESULTS

We found a significant difference in markers of inflammation as well as ceramide and phosphatidylcholine levels between patients with PAD and CAD. In contrast, basic lipid markers including total cholesterol, LDL cholesterol, HDL cholesterol, lipoprotein(a) or detailed lipoprotein profiles did not differ significantly between patients with PAD and CAD. Applying ratios and scores derived from ceramides and phosphatidylcholines further improved the discrimination between PAD and CAD. These significant differences were independent of body composition, from the status of smoking or type 2 diabetes mellitus, and also from apolipoprotein C-III and other inflammatory parameters which were different between CAD and PAD.

CONCLUSION

The present study clearly suggests that PAD and CAD differ in terms of their ceramide- and phosphatidylcholine-based lipid patterns but not in lipoprotein characteristics.

Cholesterol - the devil you know; ceramide - the devil you don't

Ectopic lipids play a key role in numerous pathologies, including heart disease, stroke, and diabetes. Of all the lipids studied, perhaps the most well understood is cholesterol, a widely used clinical biomarker of cardiovascular disease and a target of pharmacological interventions (e.g., statins). Thousands of studies have interrogated the regulation and action of this disease-causing sterol. As a growing body of literature indicates, a new class of lipid-based therapies may be on the horizon. Ceramides are cholesterol-independent biomarkers of heart disease and diabetes in humans. Studies in rodents suggest that they are causative agents of disease, as lowering ceramides through genetic or pharmacological interventions prevents cardiovascular disease and diabetes. Herein, we discuss the evidence supporting the potential of therapeutics targeting ceramides to treat cardiometabolic disease, contrasting it with the robust datasets that drove the creation of cholesterol-lowering pharmaceuticals.

A Systematic Review and Meta-Analysis of Therapeutic Efficacy and Safety of Alirocumab and Evolocumab on Familial Hypercholesterolemia

Objectives

The aim of this study was to provide the first study to systematically analyze the efficacy and safety of PCSK9-mAbs in the treatment of familial hypercholesterolemia (FH).

Methods

A computer was used to search the electronic Cochrane Library, PubMed/MEDLINE, and Embase databases for clinical trials using the following search terms: "AMG 145", "evolocumab", "SAR236553/REGN727", "alirocumab", "RG7652", "LY3015014", "RN316/bococizumab", "PCSK9", and "familial hypercholesterolemia" up to November 2020. Study quality was assessed with the Cochrane Collaboration's tool, and publication bias was evaluated by a contour-enhanced funnel plot and the Harbord modification of the Egger test. After obtaining the data, a meta-analysis was performed using R software, version 4.0.3.

Results

A meta-analysis was performed on 7 clinical trials (926 total patients). The results showed that PCSK9-mAbs reduced the LDL-C level by the greatest margin, WMD -49.14%, 95% CI: -55.81 to -42.47%, on FH versus control groups. PCSK9-mAbs also significantly reduced lipoprotein (a) (Lp (a)), total cholesterol (TC), triglycerides (TG), apolipoprotein-B (Apo-B), and non-high-density lipoprotein cholesterol (non-HDL-C) levels and increased HDL-C and apolipoprotein-A1 (Apo-A1) levels of beneficial lipoproteins. Moreover, no significant difference was found between PCSK9-mAbs treatment and placebo in common adverse events, serious events, and laboratory adverse events.

Conclusion

PCSK9-mAbs significantly decreased LDL-C and other lipid levels with satisfactory safety and tolerability in FH treatment.

Involvement of Ceramides in Non-Alcoholic Fatty Liver Disease (NAFLD) Atherosclerosis (ATS) Development: Mechanisms and Therapeutic Targets

Non-alcoholic fatty liver disease (NAFLD) and atherosclerosis (ATS) are worldwide known diseases with increased incidence and prevalence. These two are driven and are interconnected by multiple oxidative and metabolic functions such as lipotoxicity. A gamut of evidence suggests that sphingolipids (SL), such as ceramides, account for much of the tissue damage. Although in humans they are proving to be accurate biomarkers of adverse cardiovascular disease outcomes and NAFLD progression, in rodents, pharmacological inhibition or depletion of enzymes driving de novo ceramide synthesis prevents the development of metabolic driven diseases such as diabetes, ATS, and hepatic steatosis. In this narrative review, we discuss the pathways which generate the ceramide synthesis, the potential use of circulating ceramides as novel biomarkers in the development and progression of ATS and related diseases, and their potential use as therapeutic targets in NAFDL-ATS development which can further provide new clues in this field.

Aberrations in circulating ceramide levels are associated with poor clinical outcomes across localised and metastatic prostate cancer

BACKGROUND

Dysregulated lipid metabolism is associated with more aggressive pathology and poorer prognosis in prostate cancer (PC). The primary aim of the study is to assess the relationship between the plasma lipidome and clinical outcomes in localised and metastatic PC. The secondary aim is to validate a prognostic circulating 3-lipid signature specific to metastatic castration-resistant PC (mCRPC).

PATIENTS AND METHODS

Comprehensive lipidomic analysis was performed on pre-treatment plasma samples from men with localised PC (N = 389), metastatic hormone-sensitive PC (mHSPC)(N = 44), or mCRPC (validation cohort, N = 137). Clinical outcomes from our previously published mCRPC cohort (N = 159) that was used to derive the prognostic circulating 3-lipid signature, were updated. Associations between circulating lipids and clinical outcomes were examined by Cox regression and latent class analysis.

RESULTS

Circulating lipid profiles featuring elevated levels of ceramide species were associated with metastatic relapse in localised PC (HR 5.80, 95% CI 3.04-11.1, P = 1 × 10^-6), earlier testosterone suppression failure in mHSPC (HR 3.70, 95% CI 1.37-10.0, P = 0.01), and shorter overall survival in mCRPC (HR 2.54, 95% CI 1.73-3.72, P = 1 × 10^-6). The prognostic significance of circulating lipid profiles in localised PC was independent of standard clinicopathological and metabolic factors (P < 0.0002). The 3-lipid signature was verified in the mCRPC validation cohort (HR 2.39, 95% CI 1.63-3.51, P = 1 × 10^-5).

CONCLUSIONS

Elevated circulating ceramide species are associated with poorer clinical outcomes across the natural history of PC. These clinically actionable lipid profiles could be therapeutically targeted in prospective clinical trials to potentially improve PC outcomes.

Comparison of recent ceramide-based coronary risk prediction scores in cardiovascular disease patients

AIM

Cholesterol-based risk prediction is often insufficient in cardiovascular disease (CVD) patients. Ceramides are a new kind of biomarkers for CVD. The Coronary Event Risk Test (CERT) is a validated cardiovascular risk predictor that uses only circulating ceramide levels, determined by coupled liquid chromatography-mass spectrometry, to allocate patients into one of four risk categories. This test has recently been modified (CERT2) by additionally including phosphatidylcholine levels.

METHODS AND RESULTS

In this observational cohort study, we have recruited 999 Austrian patients with CVD and followed them for up to 13 years. We found that CERT and CERT2 both predicted cardiovascular events, cardiovascular mortality, and overall mortality. CERT2 had the higher performance compared to CERT and also to the recent cardiovascular risk score of the ESC/EAS guidelines (Systematic COronary Risk Evaluation (SCORE)) for low-risk European countries. Combining CERT2 with the ESC/EAS-SCORE, predictive capacity was further increased leading to a hazard ratio of 3.58 (2.02-6.36; P < 0.001) for cardiovascular events, 11.60 (2.72-49.56; P = 0.001) for cardiovascular mortality, and 9.86 (4.23-22.99; P < 0.001) for overall mortality when patients with very high risk (category 4) were compared to those with low risk (category 1). The use of the combined score instead of the ESC/EAS-SCORE significantly improved the predictive power according to the integrated discrimination improvement index (P = 0.004).

CONCLUSION

We conclude that CERT and CERT2 are powerful predictors of cardiovascular events, cardiovascular mortality, and overall mortality in CVD patients. Including phosphatidylcholine to a ceramide-based score increases the predictive performance and is best in combination with classical risk factors as used in the ESC/EAS-SCORE.

Changes in plasma sphingolipid levels against the background of lipid-lowering therapy in patients with premature atherosclerosis

Lipid-lowering drugs affect standard lipoproteins. However, we have no knowledge of changes in other plasma lipids upon treatment. The study was aimed to assess the dynamic changes in cholesterol, high- and low-density lipoproteins (HDL and LDL), triglycerides, and sphingolipids against the background of lipidlowering therapy in patients with premature coronary artery disease, atherosclerosis and hypercholesterolemia. A total of 18 patients were enrolled (the average age was 53 ± 6.7 years): in group 1, six patients received starting statin doses; group 2 included six patients, who failed to achieve LDL target levels against the background of treatment with starting statin doses, and received escalated statin doses; seven patients in group 3 failed to achieve LDL target levels against the background of treatment with maximum tolerated doses of statins and ezetimibe, and received alirocumab. Sphingolipid levels were assessed by mass spectrometry. In group 1, the decreased levels of ceramide Cer 14:1 (p = 0.046) and sphingomyelins SM 22:1, SM 22:0, SM 24:0 (p = 0.028) were observed. There were no significant changes in the levels of total cholesterol, LDL-C, HDL-C, and triglycerides. In group 2, the significantly decreased levels of total cholesterol (p = 0.028), LDL (p = 0.043), sphingomyelins SM 18:1, SM 24:1 and SM 26:1, and ceramide Cer 16:1 (p = 0.028) were observed. The level of Cer 22:1 significantly increased (p = 0.028). In group 3, total cholesterol decreased by 36.2%, and LDL-C (p = 0.018) decreased by 60.1% compared to baseline (ΔLDL-C = –2.67 ± 3.12); the elevated levels of ceramide Cer 22:1 (p = 0.028) were observed. It has been shown, that decreased sphingomyelin levels are associated with statin therapy and correlate with decreased levels of LDL-C. No significant dynamic changes in ceramides and ceramide risk against the background of statin therapy were observed, however, PCSK9 inhibitor added to therapy reduced the Cer 16:0/24:0 ratio.

Primary cardiovascular risk prediction by LDL-cholesterol in Caucasian middle-aged and older adults: a joint analysis of three cohorts

AIMS

Low-density lipoprotein cholesterol (LDL-C) is an established causal driver of atherosclerotic cardiovascular disease (ASCVD), but its performance and age-dependency as a biomarker for incident events and mortality arising from ASCVD is less clear. The aim was to determine the value of LDL-C as a susceptibility/risk biomarker for incident coronary heart disease (CHD), ASCVD, and stroke events and deaths, for the age groups <50 and ≥50 years.

METHODS AND RESULTS

The performance of LDL-C was evaluated in three cohorts, FINRISK 2002 (n = 7709), HUSK (n = 5431), and ESTHER (n = 4559), by Cox proportional hazards models, C-statistics, and net reclassification index calculations. Additionally, the hazard ratios (HRs) for the three cohorts were pooled by meta-analysis. The most consistent association was observed for CHD [95% confidence interval (CI) for HRs per standard deviation ranging from 0.99 to 1.37], whereas the results were more modest for ASCVD (0.96-1.18) due to lack of association with stroke (0.77-1.24). The association and discriminatory value of LDL-C with all endpoints in FINRISK 2002 and HUSK were attenuated in subjects 50 years and older [HRs (95% CI) obtained from meta-analysis 1.11 (1.04-1.18) for CHD, 1.15 (1.02-1.29) for CHD death, 1.02 (0.98-1.06) for ASCVD, 1.12 (1.02-1.23) for ASCVD death, and 0.97 (0.89-1.05) for stroke].

CONCLUSION

In middle-aged and older adults, associations between LDL-C and all the studied cardiovascular endpoints were relatively weak, while LDL-C showed stronger association with rare events of pre-mature CHD or ASCVD death among middle-aged adults. The predictive performance of LDL-C also depends on the studied cardiovascular endpoint.

Aggregation Susceptibility of Low-Density Lipoproteins-A Novel Modifiable Biomarker of Cardiovascular Risk

Circulating low-density lipoprotein (LDL) particles enter the arterial intima where they bind to the extracellular matrix and become modified by lipases, proteases, and oxidizing enzymes and agents. The modified LDL particles aggregate and fuse into larger matrix-bound lipid droplets and, upon generation of unesterified cholesterol, cholesterol crystals are also formed. Uptake of the aggregated/fused particles and cholesterol crystals by macrophages and smooth muscle cells induces their inflammatory activation and conversion into foam cells. In this review, we summarize the causes and consequences of LDL aggregation and describe the development and applications of an assay capable of determining the susceptibility of isolated LDL particles to aggregate when exposed to human recombinant sphingomyelinase enzyme ex vivo. Significant person-to-person differences in the aggregation susceptibility of LDL particles were observed, and such individual differences largely depended on particle lipid composition. The presence of aggregation-prone LDL in the circulation predicted future cardiovascular events in patients with atherosclerotic cardiovascular disease. We also discuss means capable of reducing LDL particles' aggregation susceptibility that could potentially inhibit LDL aggregation in the arterial wall. Whether reductions in LDL aggregation susceptibility are associated with attenuated atherogenesis and a reduced risk of atherosclerotic cardiovascular diseases remains to be studied.

Going "Green" in the Prevention and Management of Atherothrombotic Diseases: The Role of Dietary Polyphenols

During the 20th century processed and ready-to-eat foods became routinely consumed resulting in a sharp rise of fat, salt, and sugar intake in people's diets. Currently, the global incidence of obesity, raised blood lipids, hypertension, and diabetes in an increasingly aged population contributes to the rise of atherothrombotic events and cardiovascular diseases (CVD) mortality. Drug-based therapies are valuable strategies to tackle and help manage the socio-economic impact of atherothrombotic disorders though not without adverse side effects. The inclusion of fresh fruits and vegetables rich in flavonoids to human diets, as recommended by WHO offers a valuable nutritional strategy, alternative to drug-based therapies, to be explored in the prevention and management of atherothrombotic diseases at early stages. Though polyphenols are mostly associated to color and taste in foods, food flavonoids are emerging as modulators of cholesterol biosynthesis, appetite and food intake, blood pressure, platelet function, clot formation, and anti-inflammatory signaling, supporting the health-promoting effects of polyphenol-rich diets in mitigating the impact of risk factors in atherothrombotic disorders and CVD events. Here we overview the current knowledge on the effect of polyphenols particularly of flavonoid intake on the atherothrombotic risk factors and discuss the caveats and challenges involved with current experimental cell-based designs.

Development and validation of a ceramide- and phospholipid-based cardiovascular risk estimation score for coronary artery disease patients

AIMS

Distinct ceramide lipids have been shown to predict the risk for cardiovascular disease (CVD) events, especially cardiovascular death. As phospholipids have also been linked with CVD risk, we investigated whether the combination of ceramides with phosphatidylcholines (PCs) would be synergistic in the prediction of CVD events in patients with atherosclerotic coronary heart disease in three independent cohort studies.

METHODS AND RESULTS

Ceramides and PCs were analysed using liquid chromatography-mass spectrometry (LC-MS) in three studies: WECAC (The Western Norway Coronary Angiography Cohort) (N = 3789), LIPID (Long-Term Intervention with Pravastatin in Ischaemic Disease) trial (N = 5991), and KAROLA (Langzeiterfolge der KARdiOLogischen Anschlussheilbehandlung) (N = 1023). A simple risk score, based on the ceramides and PCs showing the best prognostic features, was developed in the WECAC study and validated in the two other cohorts. This score was highly significant in predicting CVD mortality [multiadjusted hazard ratios (HRs; 95% confidence interval) per standard deviation were 1.44 (1.28-1.63) in WECAC, 1.47 (1.34-1.61) in the LIPID trial, and 1.69 (1.31-2.17) in KAROLA]. In addition, a combination of the risk score with high-sensitivity troponin T increased the HRs to 1.63 (1.44-1.85) and 2.04 (1.57-2.64) in WECAC and KAROLA cohorts, respectively. The C-statistics in WECAC for the risk score combined with sex and age was 0.76 for CVD death. The ceramide-phospholipid risk score showed comparable and synergistic predictive performance with previously published CVD risk models for secondary prevention.

CONCLUSION

A simple ceramide- and phospholipid-based risk score can efficiently predict residual CVD event risk in patients with coronary artery disease.

PCSK9 Levels and Metabolic Profiles in Elderly Subjects with Different Glucose Tolerance under Statin Therapy

Proprotein convertase subtilisin/kexin type 9 (PCSK9) degrades low-density lipoprotein cholesterol (LDL-C) receptors, and thus regulates the LDL-C levels in the circulation. Type 2 diabetics often have elevated LDL-C levels. However, the functions of PCSK9 in patients with alterations of glu-cose metabolism and statin therapy are still unclear. Method: we investigated a large cohort of 608 subjects, born in 1945 in Oulu, Finland (Oulu Cohort 1945). We studied the effects of PSCK9 lev-els with different glucose tolerances (normal glucose tolerance (NGT), prediabetes (PreDM) or type 2 diabetes (T2D)) with and without statin medication, and analyzed clinical data, NMR metabolomics and PCSK9 plasma levels. Results: PCSK9 plasma levels did not significantly differ between the three groups. Statin therapy significantly increased the PCSK9 levels in NGT, PreDM and T2D groups compared with subjects with no statins. In the NGT group, negative associations between PCSK9 and LDL-C, intermediate-density lipoprotein cholesterol (IDL-C), very low-density lipoprotein cholesterol (VLDL-C), total cholesterol and LDL and IDL triglycerides were observed under statin medication. In contrast, in the PreDM and T2D groups, these associa-tions were lost. Conclusions: our data suggest that in subjects with abnormal glucose metabolism and statin therapy, the significant PCSK9-mediated effects on the lipid metabolites are lost com-pared to NGT subjects, but statins reduced the LDL-C and VLDL-C levels.

Proprotein convertase subtilisin/kexin type 9 (PCSK9) levels are not associated with severity of liver disease and are inversely related to cholesterol in a cohort of thirty eight patients with liver cirrhosis

BACKGROUND

Proprotein convertase subtilisin/kexin type 9 (PCSK9) is of particular importance in cholesterol metabolism with high levels contributing to hypercholesterolemia. Cholesterol and sphingolipids are low in patients with liver cirrhosis. Purpose of this study was to find associations of plasma PCSK9 with circulating cholesterol and sphingolipid species and measures of liver disease severity in patients with liver cirrhosis.

METHODS

PCSK9 protein levels were determined by ELISA in systemic vein (SVP), hepatic vein (HVP) and portal vein plasma of patients with mostly alcoholic liver cirrhosis. PCSK9 and LDL-receptor protein expression were analysed in cirrhotic and non-cirrhotic liver tissues.

RESULTS

Serum PCSK9 was reduced in patients with liver cirrhosis in comparison to non-cirrhotic patients. In liver cirrhosis, plasma PCSK9 was not correlated with Child-Pugh score, Model for End-Stage Liver Disease score, bilirubin or aminotransferases. A negative association of SVP PCSK9 with albumin existed. PCSK9 protein in the liver did not change with fibrosis stage and was even positively correlated with LDL-receptor protein levels. Ascites volume and variceal size were not related to PCSK9 levels. Along the same line, transjugular intrahepatic shunt to lower portal pressure did not affect PCSK9 concentrations in the three blood compartments. Serum cholesterol, sphingomyelin and ceramide levels did not correlate with PCSK9. Stratifying patients by high versus low PCSK9 levels using the median as cut-off, several cholesteryl ester species were even low in the subgroup with high PCSK9 levels. A few sphingomyelin species were also reduced in the patients with PCSK9 levels above the median. PCSK9 is highly expressed in the liver but systemic, portal and hepatic vein levels were similar. PCSK9 was not correlated with the inflammatory proteins C-reactive protein, IL-6, galectin-3, resistin or pentraxin 3. Of note, HVP PCSK9 was positively associated with HVP chemerin and negatively with HVP adiponectin levels.

CONCLUSIONS

In the cohort of patients with liver cirrhosis mostly secondary to alcohol consumption high PCSK9 was associated with low levels of certain cholesteryl ester and sphingomyelin species. Positive correlations of PCSK9 and LDL-receptor protein in the liver of patients with chronic liver injury are consistent with these findings.

Fisetin ameliorates atherosclerosis by regulating PCSK9 and LOX-1 in apoE-/- mice

The purpose of the current study was to investigate the mechanism by which fisetin improves atherosclerosis (AS) by regulating lipid metabolism and senescence in apolipoprotein E-deficient (apoE^-/-) mice. An AS model was established by feeding apoE^-/- mice a high-fat diet. Mice were randomly divided into the model group (n=18), the fisetin group (n=18) and the atorvastatin group (n=18). The control group (n=18) was composed of wild-type C57BL/6 mice of the same age and genetic background. The fisetin and atorvastatin groups were respectively treated with aqueous solutions of fisetin (12.5 mg/kg) and atorvastatin (2 mg/kg) via oral gavage daily for 12 weeks. The pathological morphology, lipid accumulation, collagen deposition of the aortic sinus were observed, serum lipids, superoxide dismutase (SOD) and malondialdehyde (MDA) levels and alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities were measured in the peripheral blood serum. Additionally, the expressions of proprotein convertase subtilisin/kexin type 9 (PCSK9), lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1), tumor suppressor protein p53 (p53), cyclin-dependent kinase inhibitor 1A (p21) and multiple tumor suppressor-1 (p16) were analyzed in the aorta. The results of the current study indicated that compared with the control group, a large area of AS plaque in the aortic sinus that contained a large amount of red-stained lipids and decreased collagen fiber content were found in the model group, which exhibited higher total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), very low-density lipoprotein cholesterol (VLDL-C), oxidized low-density lipoprotein (ox-LDL) and MDA levels; higher ALT and AST activities, lower high-density lipoprotein cholesterol (HDL-C) and SOD levels and increased expression levels of PCSK9, LOX-1, p53, p21 and p16. Fisetin is a phytochemical and bioflavonoid that serves a potential role in chronic diseases including AS, obesity, diabetes and cancer due to its wide biological activities, such as regulating lipid metabolism and anti-aging, anti-oxidation and anti-inflammatory. Atorvastatin is recognized as a first-line treatment drug for AS; therefore it was used as a positive control in the current study. Following fisetin and atorvastatin treatment, both the AS plaque and the lipid accumulation in the aortic sinus were significantly reduced, and the expressions of PCSK9, LOX-1 and aging markers, including p53, p21 and p16 were downregulated.

Ceramides in Metabolism: Key Lipotoxic Players

The global prevalence of metabolic diseases such as type 2 diabetes mellitus, steatohepatitis, myocardial infarction, and stroke has increased dramatically over the past two decades. These obesity-fueled disorders result, in part, from the aberrant accumulation of harmful lipid metabolites in tissues not suited for lipid storage (e.g., the liver, vasculature, heart, and pancreatic beta-cells). Among the numerous lipid subtypes that accumulate, sphingolipids such as ceramides are particularly impactful, as they elicit the selective insulin resistance, dyslipidemia, and ultimately cell death that underlie nearly all metabolic disorders. This review summarizes recent findings on the regulatory pathways controlling ceramide production, the molecular mechanisms linking the lipids to these discrete pathogenic events, and exciting attempts to develop therapeutics to reduce ceramide levels to combat metabolic disease.

Ceramides improve atherosclerotic cardiovascular disease risk assessment beyond standard risk factors

Ceramides are bioactive lipids that act as secondary messengers for both intra- and inter-cellular signaling. Elevated plasma concentrations of ceramides are associated with multiple risk factors of atherosclerotic cardiovascular diseases and comorbidities including obesity, insulin resistance and diabetes mellitus. Furthermore, atherosclerotic plaques have been shown to be highly enriched with ceramides. Increases in ceramide content may accelerate atherosclerosis development by promoting LDL infiltration to the endothelium and aggregation within the intima of artery walls. Thus, ceramides appear to play a key role in the development of cardiometabolic disease due to their central location in major metabolic pathways that intersect lipid and glucose metabolism. Recently published data have shown that ceramides are not only of scientific interest but may also have diagnostic value. Their independent prognostic value for future cardiovascular outcomes over and above LDL cholesterol and other traditional risk factors have consistently been shown in numerous clinical studies. Thus, ceramide testing with a mass spectrometer offers a simple, reproducible and cost-effective blood test for risk stratification in atherosclerotic cardiovascular diseases.

Treatment with PCSK9 inhibitors induces a more anti-atherogenic HDL lipid profile in patients at high cardiovascular risk

BACKGROUND

Proprotein Convertase Subtilisin/Kexin type 9 inhibitors (PCSK9-I) have been reported to cause a moderate increase in high-density lipoprotein (HDL) cholesterol in human studies. We thus evaluated the effect of two approved PCSK9-I on the concentration and lipid composition of HDL particle subclasses.

SUBJECTS AND METHODS

95 patients (62.8 ± 10.3 years old, 58% men), with or without statin and/or ezetimibe treatment and eligible for PCSK9-I therapy, received either evolocumab (140 mg) or alirocumab (75 or 150 mg). Their HDL particle profiles were measured by NMR spectroscopy at baseline and after 4 weeks of PCSK9-I treatment.

RESULTS

PCSK9-I treatment increased the level of HDL-C by 7%. The level of medium-sized HDL particles (M-HDL-P) increased (+8%) while the level of XL-HDL-P decreased (-19%). The lipid core composition was altered in the smaller S- and M-HDL-P, with a reduction in triglycerides (TG) and an enrichment in cholesterol esters (CE), whereas the for the larger XL- and L-HDL-P the relative CE content decreased and the TG content increased. Ezetimibe therapy differentially impacted the HDL particle distribution, independently of statin use, with an increase in S-HDL-P in patients not receiving ezetimibe.

CONCLUSIONS

As S- and M-HDL-P levels are inversely related to cardiovascular risk, PCSK9-I treatment may result in a more atheroprotective HDL particle profile, particularly in patients not concomitantly treated with ezetimibe.

Effect of Proprotein Convertase Subtilisin/Kexin Type 9 Inhibitors on Plasma Ceramide Levels

Proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors are novel drugs that provide striking lowering of low-density lipoprotein cholesterol (LDL-C) when added to maximum tolerated therapy in patients with hypercholesterolemia. Ceramides, novel cardiac risk markers, have been associated with increased cardiovascular mortality, independent of traditional cardiovascular risk factors. The Ceramide Risk Score (CRS) predicts the likelihood of adverse cardiovascular events within 1 to 3 years in patients with coronary artery disease. The effect of PCSK9 inhibition on plasma ceramides is not well known. The study examines the effect of PCSK9 inhibitors on plasma ceramides and CRS in patients with clinical indication for this therapy. Retrospective chart review of consecutive patients with hypercholesterolemia on PCSK9 inhibitors was conducted (n = 24; Mayo Clinic 2015 to 2018). Plasma ceramides were measured before the initiation of PCSK9 inhibitors and 2 to 12 months after treatment. CRS was calculated before and after therapy based on individual plasma concentrations of 4 ceramides. Treatment with PCSK9 inhibitors was associated with significant reduction in mean CRS and individual ceramides levels (p <0.0001). CRS significantly improved with PCSK9 therapy. PCSK9 inhibitors significantly decreased LDL-C levels by 63% (p <0.0001). The absolute reduction in CRS did not correlate with the absolute reduction in LDL-C (r = 0.31; confidence interval -0.10 to 0.64), indicating that CRS may evaluate a different pathway for risk reduction beyond LDL-C lowering. In conclusion, treatment with PCSK9 inhibitors is associated with significant reduction in CRS and distinct ceramide levels.

Interactions of dietary polyphenols with epithelial lipids: advances from membrane and cell models in the study of polyphenol absorption, transport and delivery to the epithelium

Currently, diet-related diseases such as diabetes, obesity, hypertension, and cardiovascular diseases account for 70% of all global deaths. To counteract the rising prevalence of non-communicable diseases governments are investing in persuasive educational campaigns toward the ingestion of fresh fruits and vegetables. The intake of dietary polyphenols abundant in Mediterranean and Nordic-type diets holds great potential as nutritional strategies in the management of diet-related diseases. However, the successful implementation of healthy nutritional strategies relies on a pleasant sensory perception in the mouth able to persuade consumers to adopt polyphenol-rich diets and on a deeper understanding on the chemical modifications, that affect not only their chemical properties but also their physical interaction with epithelial lipids and in turn their permeability, location within the lipid bilayer, toxicity and biological activity, and fate during absorption at the gastro-intestinal epithelium, transport in circulation and delivery to the endothelium. In this paper, we review the current knowledge on the interactions between polyphenols and their metabolites with membrane lipids in artificial membranes and epithelial cell models (oral, stomach, gut and endothelium) and the findings from polyphenol-lipid interactions to physiological processes such as oral taste perception, gastrointestinal absorption and endothelial health. Finally, we discuss the limitations and challenges associated with the current experimental approaches in membrane and cell model studies and the potential of polyphenol-rich diets in the quest for personalized nutritional strategies ("personalized nutrition") to assist in the prevention, treatment, and management of non-communicable diseases in an increasingly aged population.

LDL subclass lipidomics in atherogenic dyslipidemia: effect of statin therapy on bioactive lipids and dense LDL

Atherogenic LDL particles are physicochemically and metabolically heterogeneous. Can bioactive lipid cargo differentiate LDL subclasses, and thus potential atherogenicity? What is the effect of statin treatment? Obese hypertriglyceridemic hypercholesterolemic males [n = 12; lipoprotein (a) <10 mg/dl] received pitavastatin calcium (4 mg/day) for 180 days in a single-phase unblinded study. The lipidomic profiles (23 lipid classes) of five LDL subclasses fractionated from baseline and post-statin plasmas were determined by LC-MS. At baseline and on statin treatment, very small dense LDL (LDL5) was preferentially enriched (up to 3-fold) in specific lysophospholipids {LPC, lysophosphatidylinositol (LPI), lysoalkylphosphatidylcholine [LPC(O)]; 9, 0.2, and 0.14 mol per mole of apoB, respectively; all P < 0.001 vs. LDL1-4}, suggesting elevated inflammatory potential per particle. In contrast, lysophosphatidylethanolamine was uniformly distributed among LDL subclasses. Statin treatment markedly reduced absolute plasma concentrations of all LDL subclasses (up to 33.5%), including LPC, LPI, and LPC(O) contents (up to -52%), consistent with reduction in cardiovascular risk. Despite such reductions, lipotoxic ceramide load per particle in LDL1-5 (1.5-3 mol per mole of apoB; 3-7 mmol per mole of PC) was either conserved or elevated. Bioactive lipids may constitute biomarkers for the cardiometabolic risk associated with specific LDL subclasses in atherogenic dyslipidemia at baseline, and with residual risk on statin therapy.

ANGPTL3 deficiency alters the lipid profile and metabolism of cultured hepatocytes and human lipoproteins

Loss-of-function (LOF) mutations in ANGPTL3, an inhibitor of lipoprotein lipase (LPL), cause a drastic reduction of serum lipoproteins and protect against the development of atherosclerotic cardiovascular disease. Therefore, ANGPTL3 is a promising therapy target. We characterized the impacts of ANGPTL3 depletion on the immortalized human hepatocyte (IHH) transcriptome, lipidome and human plasma lipoprotein lipidome. The transcriptome of ANGPTL3 knock-down (KD) cells showed altered expression of several pathways related to lipid metabolism. Accordingly, ANGPTL3 depleted IHH displayed changes in cellular overall fatty acid (FA) composition and in the lipid species composition of several lipid classes, characterized by abundant n-6 and n-3 polyunsaturated FAs (PUFAs). This PUFA increase coincided with an elevation of lipid mediators, among which there were species relevant for resolution of inflammation, protection from lipotoxic and hypoxia-induced ER stress, hepatic steatosis and insulin resistance or for the recovery from cardiovascular events. Cholesterol esters were markedly reduced in ANGPTL3 KD IHH, coinciding with suppression of the SOAT1 mRNA and protein. ANGPTL3 LOF caused alterations in plasma lipoprotein FA and lipid species composition. All lipoprotein fractions of the ANGPTL3 LOF subjects displayed a marked drop of 18:2n-6, while several highly unsaturated triacylglycerol (TAG) species were enriched. The present work reveals distinct impacts of ANGPTL3 depletion on the hepatocellular lipidome, transcriptome and lipid mediators, as well as on the lipidome of lipoproteins isolated from plasma of ANGPTL3-deficient human subjects. It is important to consider these lipidomics and transcriptomics findings when targeting ANGPTL3 for therapy and translating it to the human context.

Machine learning reveals serum sphingolipids as cholesterol-independent biomarkers of coronary artery disease

BACKGROUNDCeramides are sphingolipids that play causative roles in diabetes and heart disease, with their serum levels measured clinically as biomarkers of cardiovascular disease (CVD).METHODSWe performed targeted lipidomics on serum samples from individuals with familial coronary artery disease (CAD) (n = 462) and population-based controls (n = 212) to explore the relationship between serum sphingolipids and CAD, using unbiased machine learning to identify sphingolipid species positively associated with CAD.RESULTSNearly every sphingolipid measured (n = 30 of 32) was significantly elevated in subjects with CAD compared with measurements in population controls. We generated a novel sphingolipid-inclusive CAD risk score, termed SIC, that demarcates patients with CAD independently and more effectively than conventional clinical CVD biomarkers including serum LDL cholesterol and triglycerides. This new metric comprises several minor lipids that likely serve as measures of flux through the ceramide biosynthesis pathway rather than the abundant deleterious ceramide species that are included in other ceramide-based scores.CONCLUSIONThis study validates serum ceramides as candidate biomarkers of CVD and suggests that comprehensive sphingolipid panels should be considered as measures of CVD.FUNDINGThe NIH (DK112826, DK108833, DK115824, DK116888, and DK116450); the Juvenile Diabetes Research Foundation (JDRF 3-SRA-2019-768-A-B); the American Diabetes Association; the American Heart Association; the Margolis Foundation; the National Cancer Institute, NIH (5R00CA218694-03); and the Huntsman Cancer Institute Cancer Center Support Grant (P30CA040214).