Increased Plasma Apolipoprotein C-III Concentration Independently Predicts Cardiovascular Mortality: The Hoorn Study

Exploring apolipoprotein C-III: pathophysiological and pharmacological relevance

The availability of pharmacological approaches able to effectively reduce circulating LDL cholesterol (LDL-C) has led to a substantial reduction in the risk of atherosclerosis-related cardiovascular disease (CVD). However, a residual cardiovascular (CV) risk persists in treated individuals with optimal levels of LDL-C. Additional risk factors beyond LDL-C are involved, and among these, elevated levels of triglycerides (TGs) and TG-rich lipoproteins are causally associated with an increased CV risk. Apolipoprotein C-III (apoC-III) is a key regulator of TG metabolism and hence circulating levels through several mechanisms including the inhibition of lipoprotein lipase activity and alterations in the affinity of apoC-III-containing lipoproteins for both the hepatic receptors involved in their removal and extracellular matrix in the arterial wall. Genetic studies have clarified the role of apoC-III in humans, establishing a causal link with CVD and showing that loss-of-function mutations in the APOC3 gene are associated with reduced TG levels and reduced risk of coronary heart disease. Currently available hypolipidaemic drugs can reduce TG levels, although to a limited extent. Substantial reductions in TG levels can be obtained with new drugs that target specifically apoC-III; these include two antisense oligonucleotides, one small interfering RNA and an antibody.

A Current Update on the Role of HDL-Based Nanomedicine in Targeting Macrophages in Cardiovascular Disease

High-density lipoproteins (HDL) are complex endogenous nanoparticles involved in important functions such as reverse cholesterol transport and immunomodulatory activities, ensuring metabolic homeostasis and vascular health. The ability of HDL to interact with a plethora of immune cells and structural cells places it in the center of numerous disease pathophysiologies. However, inflammatory dysregulation can lead to pathogenic remodeling and post-translational modification of HDL, rendering HDL dysfunctional or even pro-inflammatory. Monocytes and macrophages play a critical role in mediating vascular inflammation, such as in coronary artery disease (CAD). The fact that HDL nanoparticles have potent anti-inflammatory effects on mononuclear phagocytes has opened new avenues for the development of nanotherapeutics to restore vascular integrity. HDL infusion therapies are being developed to improve the physiological functions of HDL and to quantitatively restore or increase the native HDL pool. The components and design of HDL-based nanoparticles have evolved significantly since their initial introduction with highly anticipated results in an ongoing phase III clinical trial in subjects with acute coronary syndrome. The understanding of mechanisms involved in HDL-based synthetic nanotherapeutics is critical to their design, therapeutic potential and effectiveness. In this review, we provide a current update on HDL-ApoA-I mimetic nanotherapeutics, highlighting the scope of treating vascular diseases by targeting monocytes and macrophages.

Apolipoprotein C3 induces inflammasome activation only in its delipidated form

Matters arising regarding the lipidation form of plasma APOC3 that induces an alternative NLRP3 activation pathway.

Impact of triglyceride-rich lipoproteins on early in-stent neoatherosclerosis formation in patients undergoing statin treatment

BACKGROUND

Neoatherosclerosis (NA), which refers to neointimal atherosclerosis within a stent, is considered one of the underlying causes of late-phase stent failure following a newer generation drug-eluting stent (DES) placement procedure. Even contemporary guideline-directed medical therapy may be insufficient to prevent NA.

OBJECTIVE

This study aimed to investigate how intricately lipid markers are associated with NA formation in the early phase of treatment with well-maintained low-density lipoprotein cholesterol (LDL-C) levels.

METHODS

We enrolled 114 consecutive patients undergoing statin treatment and percutaneous coronary intervention (PCI) with current-generation DES for coronary artery disease. At a median 12 months after PCI, optical coherence tomography (OCT) was performed. Various lipid markers, including LDL-C, triglyceride (TG), triglyceride-rich lipoprotein cholesterol (TRL-C), non-high-density lipoprotein cholesterol (non-HDL-C), malondialdehyde-modified LDL (MDA-LDL), and several apolipoproteins, were also evaluated.

RESULTS

NA was observed in 17 (14.9%) patients. The LDL-C level was equivalent in patients with or without NA (77.2 vs. 69.8 mg/dL; p=0.15). However, the levels of TG, apolipoprotein C3 (apoC3), TRL-C, non-HDL-C, and apolipoprotein B (apoB), and MDA-LDL were significantly higher in the patients with NA. Furthermore, multivariate logistic regression adjusting for HbA1c and stent duration revealed apoC3, TRL-C, non-HDL-C, apoB, and MDA-LDL levels as risk factors for NA. However, when apoB was included as a covariate, other factors became nonsignificant.

CONCLUSIONS

Abnormal triglyceride-rich lipoprotein metabolism and high atherogenic apoB-containing lipoprotein particle numbers are associated with the formation of NA in patients undergoing statin treatment at a median 12 months post-PCI.

Apolipoprotein C3 and necrotic core volume are correlated but also associated with future cardiovascular events

We aimed to clarify the relationship between apolipoprotein C3 (apo-C3) and the vascular composition of lesion plaque in stable coronary disease (SCD) before percutaneous coronary intervention (PCI), and to investigate major adverse cardiovascular events (MACEs) within 4 years. Data of 98 consecutive patients with SCD who underwent PCI between November 1, 2012, and March 10, 2015, were analyzed. Laboratory and virtual histology-intravascular ultrasound (VH-IVUS) examinations of culprit lesions were conducted before PCI. Patients were divided according to median apo-C3 into low apo-C3 (≤ 8.5 mg/dL) and high apo-C3 (> 8.5 mg/dL) groups. VH-IVUS data indicated that the percentage of necrotic core volume (%NC) was significantly higher in the high apo-C3 group than in the low apo-C3 group. Moreover, the %NC significantly correlated with the apo-C3 level (R = 0.2109, P = 0.037). Kaplan–Meier curve analysis revealed that freedom from MACEs exhibited a greater decrease in the high apo-C3 group than in the low apo-C3 group, and in the high %NC group than in the low %NC group. Multivariate Cox hazards analysis showed that the %NC and high apo-C3 were independent predictors of 4 year MACEs. Apo-C3 may be a useful marker of future MACEs in patients with SCD after PCI and contribute to %NC growth.

Regulation of cholesterol homeostasis in health and diseases: from mechanisms to targeted therapeutics

Disturbed cholesterol homeostasis plays critical roles in the development of multiple diseases, such as cardiovascular diseases (CVD), neurodegenerative diseases and cancers, particularly the CVD in which the accumulation of lipids (mainly the cholesteryl esters) within macrophage/foam cells underneath the endothelial layer drives the formation of atherosclerotic lesions eventually. More and more studies have shown that lowering cholesterol level, especially low-density lipoprotein cholesterol level, protects cardiovascular system and prevents cardiovascular events effectively. Maintaining cholesterol homeostasis is determined by cholesterol biosynthesis, uptake, efflux, transport, storage, utilization, and/or excretion. All the processes should be precisely controlled by the multiple regulatory pathways. Based on the regulation of cholesterol homeostasis, many interventions have been developed to lower cholesterol by inhibiting cholesterol biosynthesis and uptake or enhancing cholesterol utilization and excretion. Herein, we summarize the historical review and research events, the current understandings of the molecular pathways playing key roles in regulating cholesterol homeostasis, and the cholesterol-lowering interventions in clinics or in preclinical studies as well as new cholesterol-lowering targets and their clinical advances. More importantly, we review and discuss the benefits of those interventions for the treatment of multiple diseases including atherosclerotic cardiovascular diseases, obesity, diabetes, nonalcoholic fatty liver disease, cancer, neurodegenerative diseases, osteoporosis and virus infection.

Apolipoprotein C-III predicts cardiovascular events and mortality in individuals with type 1 diabetes and albuminuria

OBJECTIVES

We studied apolipoprotein C-III (apoC-III) in relation to diabetic kidney disease (DKD), cardiovascular outcomes, and mortality in type 1 diabetes.

METHODS

The cohort comprised 3966 participants from the prospective observational Finnish Diabetic Nephropathy Study. Progression of DKD was determined from medical records. A major adverse cardiac event (MACE) was defined as acute myocardial infarction, coronary revascularization, stroke, or cardiovascular mortality through 2017. Cardiovascular and mortality data were retrieved from national registries.

RESULTS

ApoC-III predicted DKD progression independent of sex, diabetes duration, blood pressure, HbA_1c , smoking, LDL-cholesterol, lipid-lowering medication, DKD category, and remnant cholesterol (hazard ratio [HR] 1.43 [95% confidence interval 1.05-1.94], p = 0.02). ApoC-III also predicted the MACE in a multivariable regression analysis; however, it was not independent of remnant cholesterol (HR 1.05 [0.81-1.36, p = 0.71] with remnant cholesterol; 1.30 [1.03-1.64, p = 0.03] without). DKD-specific analyses revealed that the association was driven by individuals with albuminuria, as no link between apoC-III and the outcome was observed in the normal albumin excretion or kidney failure categories. The same was observed for mortality: Individuals with albuminuria had an adjusted HR of 1.49 (1.03-2.16, p = 0.03) for premature death, while no association was found in the other groups. The highest apoC-III quartile displayed a markedly higher risk of MACE and death than the lower quartiles; however, this nonlinear relationship flattened after adjustment.

CONCLUSIONS

The impact of apoC-III on MACE risk and mortality is restricted to those with albuminuria among individuals with type 1 diabetes. This study also revealed that apoC-III predicts DKD progression, independent of the initial DKD category.

Apolipoprotein C-III reduction in subjects with moderate hypertriglyceridaemia and at high cardiovascular risk

Aims

Hypertriglyceridaemia is associated with increased risk of cardiovascular events. This clinical trial evaluated olezarsen, an N-acetyl-galactosamine-conjugated antisense oligonucleotide targeted to hepatic APOC3 mRNA to inhibit apolipoprotein C-III (apoC-III) production, in lowering triglyceride levels in patients at high risk for or with established cardiovascular disease.

Methods and results

A randomized, double-blind, placebo-controlled, dose-ranging study was conducted in 114 patients with fasting serum triglycerides 200–500 mg/dL (2.26–5.65 mmol/L). Patients received olezarsen (10 or 50 mg every 4 weeks, 15 mg every 2 weeks, or 10 mg every week) or saline placebo subcutaneously for 6–12 months. The primary endpoint was the percent change in fasting triglyceride levels from baseline to Month 6 of exposure. Baseline median (interquartile range) fasting triglyceride levels were 262 (222–329) mg/dL [2.96 (2.51–3.71) mmol/L]. Treatment with olezarsen resulted in mean percent triglyceride reductions of 23% with 10 mg every 4 weeks, 56% with 15 mg every 2 weeks, 60% with 10 mg every week, and 60% with 50 mg every 4 weeks, compared with increase by 6% for the pooled placebo group (P-values ranged from 0.0042 to <0.0001 compared with placebo). Significant decreases in apoC-III, very low-density lipoprotein cholesterol, non-high-density lipoprotein cholesterol, and apolipoprotein B were also observed. There were no platelet count, liver, or renal function changes in any of the olezarsen groups. The most common adverse event was mild erythema at the injection site.

Conclusion

Olezarsen significantly reduced apoC-III, triglycerides, and atherogenic lipoproteins in patients with moderate hypertriglyceridaemia and at high risk for or with established cardiovascular disease.

Trial registration number

NCT03385239.

Apolipoprotein C-II and C-III preferably transfer to both high-density lipoprotein (HDL)2 and the larger HDL3 from very low-density lipoprotein (VLDL)

Triglyceride hydrolysis by lipoprotein lipase (LPL), regulated by apolipoproteins C-II (apoC-II) and C-III (apoC-III), is essential for maintaining normal lipid homeostasis. During triglyceride lipolysis, the apoCs are known to be transferred from very low-density lipoprotein (VLDL) to high-density lipoprotein (HDL), but the detailed mechanisms of this transfer remain unclear. In this study, we investigated the extent of the apoC transfers and their distribution in HDL subfractions, HDL2 and HDL3. Each HDL subfraction was incubated with VLDL or biotin-labeled VLDL, and apolipoproteins and lipids in the re-isolated HDL were quantified using western blotting and high-performance liquid chromatography (HPLC). In consequence, incubation with VLDL showed the increase of net amount of apoC-II and apoC-III in the HDL. HPLC analysis revealed that the biotin-labeled apolipoproteins, including apoCs and apolipoprotein E, were preferably transferred to the larger HDL3. No effect of cholesteryl ester transfer protein inhibitor on the apoC transfers was observed. Quantification of apoCs levels in HDL2 and HDL3 from healthy subjects (n = 8) showed large individual differences between apoC-II and apoC-III levels. These results suggest that both apoC-II and apoC-III transfer disproportionately from VLDL to HDL2 and the larger HDL3, and these transfers might be involved in individual triglyceride metabolism.

Targeting RNA With Antisense Oligonucleotides and Small Interfering RNA: JACC State-of-the-Art Review

There is an unmet clinical need to reduce residual cardiovascular risk attributable to apolipoprotein B-containing lipoproteins, particularly low-density lipoprotein and remnant particles. Pharmacological targeting of messenger RNA represents an emerging, innovative approach. Two major classes of agents have been developed-antisense oligonucleotides and small interfering RNA. Early problems with their use have been overcome by conjugation with N-acetylgalactosamine, an adduct that targets their delivery to the primary site of action in the liver. Using these agents to inhibit the translation of key regulatory proteins such as PCSK9, apolipoprotein CIII, apolipoprotein(a), and angiopoietin-like 3 has been shown to be effective in attenuating dyslipidemic states. Cardiovascular outcome trials with N-acetylgalactosamine-conjugated RNA-targeting drugs are ongoing. The advantages of these agents include long dosing intervals of up to 6 months and the potential to regulate the abundance of any disease-related protein. Long-term safety has yet to be demonstrated in large-scale clinical trials.

Apolipoprotein C-III and cardiovascular diseases: when genetics meet molecular pathologies

Cardiovascular diseases (CVD) have overtaken infectious diseases and are currently the world's top killer. A quite strong linkage between this type of ailments and elevated plasma levels of triglycerides (TG) has been always noticed. Notably, this risk factor is mired in deep confusion, since its role in atherosclerosis is uncertain. One of the explanations that aim to decipher this persistent enigma was provided by apolipoprotein C-III (apoC-III), a small protein historically recognized as an important regulator of TG metabolism. Preeminently, hundreds of studies have been carried out in order to explore the APOC3 genetic background, as well as to establish a correlation between its variants and dyslipidemia-related disorders, pointing to an earnest predictive power for future outcomes. Among several polymorphisms reported within the APOC3, the SstI site in its 3'-untranslated region (3'-UTR) was the most consistently and robustly associated with an increased CVD risk. As more genetic data supporting its importance in cardiovascular events aggregate, it was declared, correspondingly, that apoC-III exerts various atherogenic effects, either by intervening in the function and catabolism of many lipoproteins, or by inducing endothelial inflammation and smooth muscle cells (SMC) proliferation. This review was designed to shed the light on the structural and functional aspects of the APOC3 gene, the existing association between its SstI polymorphism and CVD, and the specific molecular mechanisms that underlie apoC-III pathological implications. In addition, the translation of all these gathered knowledges into preventive and therapeutic benefits will be detailed too.

Current Understanding of the Relationship of HDL Composition, Structure and Function to Their Cardioprotective Properties in Chronic Kidney Disease

In the general population, the ability of high-density lipoproteins (HDLs) to promote cholesterol efflux is a predictor of cardiovascular events, independently of HDL cholesterol levels. Although patients with chronic kidney disease (CKD) have a high burden of cardiovascular morbidity and mortality, neither serum levels of HDL cholesterol, nor cholesterol efflux capacity associate with cardiovascular events. Important for the following discussion on the role of HDL in CKD is the notion that traditional atherosclerotic cardiovascular risk factors only partially account for this increased incidence of cardiovascular disease in CKD. As a potential explanation, across the spectrum of cardiovascular disease, the relative contribution of atherosclerotic cardiovascular disease becomes less important with advanced CKD. Impaired renal function directly affects the metabolism, composition and functionality of HDL particles. HDLs themselves are a heterogeneous population of particles with distinct sizes and protein composition, all of them affecting the functionality of HDL. Therefore, a more specific approach investigating the functional and compositional features of HDL subclasses might be a valuable strategy to decipher the potential link between HDL, cardiovascular disease and CKD. This review summarizes the current understanding of the relationship of HDL composition, metabolism and function to their cardio-protective properties in CKD, with a focus on CKD-induced changes in the HDL proteome and reverse cholesterol transport capacity. We also will highlight the gaps in the current knowledge regarding important aspects of HDL biology.

Lipoproteins and lipids in cardiovascular disease: from mechanistic insights to therapeutic targeting

With cardiovascular disease being the leading cause of morbidity and mortality worldwide, effective and cost-efficient therapies to reduce cardiovascular risk are highly needed. Lipids and lipoprotein particles crucially contribute to atherosclerosis as underlying pathology of cardiovascular disease and influence inflammatory processes as well as function of leukocytes, vascular and cardiac cells, thereby impacting on vessels and heart. Statins form the first-line therapy with the aim to block cholesterol synthesis, but additional lipid-lowering drugs are sometimes needed to achieve low-density lipoprotein (LDL) cholesterol target values. Furthermore, beyond LDL cholesterol, also other lipid mediators contribute to cardiovascular risk. This review comprehensively discusses low- and high-density lipoprotein cholesterol, lipoprotein (a), triglycerides as well as fatty acids and derivatives in the context of cardiovascular disease, providing mechanistic insights into their role in pathological processes impacting on cardiovascular disease. Also, an overview of applied as well as emerging therapeutic strategies to reduce lipid-induced cardiovascular burden is provided.

Biotechnology Approaches for the Treatment of Dyslipidemia

BACKGROUND

Despite advances in the development of lipid-lowering therapies, clinical trials have shown that a significant residual risk of cardiovascular disease persists. Specifically, new drugs are needed for non-responding or statin-intolerant subjects or patients considered at very high risk for cardiovascular events even though are already on treatment with the best standard of care.

RESULTS AND CONCLUSIONS

Besides, genetic and epidemiological studies and Mendelian randomization analyses have strengthened the linear correlation between the concentration of low-density lipoprotein cholesterol (LDL-C) and the incidence of cardiovascular events and highlighted various novel therapeutic targets. This review describes the novel strategies to reduce the levels of LDL-C, non-HDL-C, triglyceride, apolipoprotein B, and Lp(a), focusing on those developed using biotechnology-based strategies.

Apolipoprotein CIII predicts cardiovascular events in patients with coronary artery disease: a prospective observational study

Background

Apolipoprotein CIII (apoCIII) is associated with triglyceride-rich lipoprotein metabolism and has emerged as independent marker for risk of cardiovascular disease. The objective was to test whether apoCIII is regulated postprandially and whether apoCIII concentrations in native and chylomicron-free serum predict future cardiovascular events in patients with stable coronary artery disease (CAD).

Methods

ApoCIII concentrations were measured in native and chylomicron-free serum in the fasting state and after a standardized oral fat load test in 195 patients with stable CAD. Clinical follow-up was 48 months. Chylomicron-free serum was prepared by ultracentrifugation (18,000 rpm, 3 h). The log-rank test and Cox regression analyses were used to investigate the association of apoCIII with recurrent cardiovascular events.

Results

Of the 195 patients included, 92 had a cardiovascular event, and 103 did not. 97% were treated with a statin. No significant changes in apoCIII concentration were observed after the oral fat load test. The apoCIII concentration was associated with event-free survival independent of conventional risk factors. This association reached statistical significance only for apoCIII concentration measured in chylomicron-free serum (hazard ratio [95% confidence interval] for apoCIII above the mean: postprandial: 1.67 (1.06–2.29), P = 0.028, fasting: 2.09 (1.32–3.32), P = 0.002), but not for apoCIII concentration measured in native serum (postprandial: 1.47 [0.89–2.43], P = 0.133, fasting: 1.56 [0.95–2.58], P = 0.081). The effects were independent of other risk factors.

Conclusions

ApoCIII concentrations in chylomicron-free serum are independently associated with event-free survival in patients with CAD both in fasting and postprandial state. This findings support considering apoCIII for risk assessment and attempting to test the hypothesis that lowering apoCIII reduces residual cardiovascular risk.

Take home message

Apolipoprotein CIII concentration measured in chylomicron-free serum predicts recurrent cardiovascular events in patients with stable coronary artery disease.

Trial registration

The trial which included the participants of this study was registered at https://clinicaltrials.gov (NCT00628524) on March 5, 2008.

Lipid-Lowering Agents

Several new or emerging drugs for dyslipidemia owe their existence, in part, to human genetic evidence, such as observations in families with rare genetic disorders or in Mendelian randomization studies. Much effort has been directed to agents that reduce LDL (low-density lipoprotein) cholesterol, triglyceride, and Lp[a] (lipoprotein[a]), with some sustained programs on agents to raise HDL (high-density lipoprotein) cholesterol. Lomitapide, mipomersen, AAV8.TBG.hLDLR, inclisiran, bempedoic acid, and gemcabene primarily target LDL cholesterol. Alipogene tiparvovec, pradigastat, and volanesorsen primarily target elevated triglycerides, whereas evinacumab and IONIS-ANGPTL3-L_Rx target both LDL cholesterol and triglyceride. IONIS-APO(a)-L_Rx targets Lp(a).

Tackling Residual Atherosclerotic Risk in Statin-Treated Adults: Focus on Emerging Drugs

Epidemiological studies and meta-analyses have consistently suggested the importance of lowering low-density lipoprotein cholesterol (LDL-C) to reduce cardiovascular (CV) events. However, these studies and mechanistic studies using intracoronary imaging modalities have reported patients who continue to experience CV events or disease progression despite optimal LDL-C levels on statins. These findings, including statin intolerance, have highlighted the importance of exploring additional potential therapeutic targets to reduce CV risk. Genomic insights have presented a number of additional novel targets in lipid metabolism. In particular, proprotein convertase subtilisin/kexin type 9 inhibitors have rapidly developed and recently demonstrated their beneficial impact on CV outcomes. Triglyceride (TG)-rich lipoproteins have been recently reported as a causal factor of atherosclerotic cardiovascular disease (ASCVD). Indeed, several promising TG-targeting therapies are being tested at various clinical stages. In this review, we present the evidence to support targeting atherogenic lipoproteins to target residual ASCVD risk in statin-treated patients.

Effect of fenofibrate on plasma apolipoprotein C-III levels: a systematic review and meta-analysis of randomised placebo-controlled trials

OBJECTIVES

This meta-analysis of randomised placebo-controlled clinical trials aimed to assess the effect of fenofibrate on apolipoprotein C-III (apo C-III), a key regulator of triglyceride metabolism.

MATERIALS AND METHODS

Randomised placebo-controlled trials investigating the impact of fenofibrate treatment on apo C-III levels were searched in PubMed-Medline, Scopus, Web of Science and Google Scholar databases from inception to 18 August 2017. Quantitative data synthesis was determined by a random-effects model and generic inverse variance method. Sensitivity analysis was conducted using the leave-one-out method. A weighted random-effects meta-regression was performed to evaluate glycaemic parameter confounders.

RESULTS

Meta-analysis of 10 clinical trials involving 477 subjects showed fenofibrate therapy decreased apo C-III levels (weighted mean difference (WMD) -4.78 mg/dL, 95% CI -6.95 to -2.61, p<0.001; I²66.87%). Subgroup analysis showed that fenofibrate reduced plasma apo C-III concentrations in subgroups of trials with treatment durations of either <12 weeks (WMD -4.50 mg/dL, p=0.001) or ≥12 weeks (WMD: -4.73 mg/dL, p=0.009) and doses of fenofibrate <200 mg/day (WMD -6.33 mg/dL, p<0.001) and >200 mg/day (p=0.006), with no significant difference between the subgroups.

CONCLUSION

This meta-analysis found that fenofibrate therapy significantly decreases apo C-III levels, an effect evident with both short-term treatment and doses less than 200 mg/day.

Experimental therapies targeting apolipoprotein C-III for the treatment of hyperlipidemia - spotlight on volanesorsen

INTRODUCTION

Despite the substantial reduction in cardiovascular morbidity and mortality after the management of dyslipidemia with statins, residual risk remains even after achieving low-density lipoprotein cholesterol targets. This residual risk appears to be partly attributed to low levels of high-density lipoprotein cholesterol (HDL-C) and high levels of triglycerides (TG). Apolipoprotein C3 (APOC3) is a key regulator of TG metabolism and its targeting may reduce TG levels and cardiovascular risk.

AREAS COVERED

We discuss APOC3-targeted experimental treatments for dyslipidemia. There is an emphasis on volanesorsen because it the agent in the most advanced stage of development. M580, a retinoic acid receptor-α specific agonist, an agent in early-stage development is briefly covered. Preclinical data suggest that this agent decreases APOC3 mRNA levels and reduces total cholesterol, TG levels and hepatic lipid accumulation.

EXPERT OPINION

The effects of this novel therapeutic approach on cardiovascular morbidity and mortality should be determined in randomized controlled trials. The cost of volanesorsen, the unfavorable safety profile and the need for subcutaneous administration present barriers to long-term use. AM580 may hold promise in the management of hypertriglyceridemia but further investigations are necessary to evaluate safety and efficacy.

MicroRNAs: Novel Molecular Targets and Response Modulators of Statin Therapy

Cardiovascular disease (CVD) is a major cause of death globally. Addressing cardiovascular risk factors, particularly dyslipidemia, represents the most robust clinical strategy towards reducing the CVD burden. Statins inhibit 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) reductase and represent the main therapeutic approach for lowering cholesterol and reducing plaque formation/rupture. The protective effects of statins extend beyond lowering cholesterol. MicroRNAs (miRNAs or miRs), small noncoding regulatory RNAs, likely mediate the positive pleiotropic effects of statins via modulation of lipid metabolism, enhancement of endothelial function, inhibition of inflammation, improvement of plaque stability, and immune regulation. miRNAs are implicated in statin-related interindividual variations in therapeutic response, directly via HMG-CoA reductase, or indirectly through targeting cytochrome P450 3A (CYP3A) functionality and proprotein convertase subtilisin/kexin type9 (PCSK9) biology.

Relationship of lipoprotein-associated apolipoprotein C-III with lipid variables and coronary artery disease risk: The EPIC-Norfolk prospective population study

BACKGROUND

Plasma apolipoprotein C-III (apoC-III) levels are associated with coronary artery disease (CAD) risk.

OBJECTIVE

To assess whether lipoprotein-associated apoC-III levels predict risk of CAD events.

METHODS

apoC-III associated with apoB, apoAI, and Lp(a) (apoCIII-apoB, apoCIII-apoAI, and apoCIII-Lp(a), respectively) were measured using high-throughput chemiluminescent enzyme-linked immunoassays in 2711 subjects (1879 controls and 832 cases with CAD) in the European Prospective Investigation into Cancer and Nutrition-Norfolk prospective population study with 7.4 years of follow-up. These measures were correlated with a variety of lipid measurements and the presence of CAD. The indices of "total apoCIII-apoB" and "total apoCIII-apoAI" were derived by multiplying plasma apoB and apoAI, respectively.

RESULTS

apoCIII-apoB (P = .001), apoCIII-Lp(a) (P < .001), apoCIII-apoAI (P = .005) were higher in cases vs controls; tended to correlate positively with body mass index, hsCRP, apoC-III, low-density lipoprotein (LDL) cholesterol, triglycerides, remnant cholesterol, very low density lipoprotein, LDL and high-density lipoprotein particle number and very low density lipoprotein size; but negatively with LDL and high-density lipoprotein particle size (P < .001 for all). apoCIII-apoB, apoCIII-apoAI, apoCIII-Lp(a), total apoCIII-Lp(a), and total apoCIII-apoB were predictors of CAD after adjustment of age, sex, body mass index, smoking, diabetes, hypertensive and lipid-lowering drug use, but they lost their significance after further adjustment of lipid and lipoprotein variables.

CONCLUSIONS

This study suggests that enzyme-linked immunoassay-measured lipoprotein-associated apoC-III markers reflect atherogenic lipid particles but do not independently predict risk of CAD events.

New medications targeting triglyceride-rich lipoproteins: Can inhibition of ANGPTL3 or apoC-III reduce the residual cardiovascular risk?

Remarkably good results have been achieved in the treatment of atherosclerotic cardiovascular diseases (CVD) by using statin, ezetimibe, antihypertensive, antithrombotic, and PCSK9 inhibitor therapies and their proper combinations. However, despite this success, the remaining CVD risk is still high. To target this residual risk and to treat patients who are statin-intolerant or have an exceptionally high CVD risk for instance due to familial hypercholesterolemia (FH), new therapies are intensively sought. One pathway of drug development is targeting the circulating triglyceride-rich lipoproteins (TRL) and their lipolytic remnants, which, according to the current view, confer a major CVD risk. Angiopoietin-like protein 3 (ANGPTL3) and apolipoprotein C-III (apoC-III) are at present the central molecular targets for therapies designed to reduce TRL, and there are new drugs emerging that suppress their expression or inhibit the function of these two key proteins. The medications targeting these components are biological, either human monoclonal antibodies or antisense oligonucleotides. In this article, we briefly review the mechanisms of action of ANGPTL3 and apoC-III, the reasons why they have been considered promising targets of novel therapies for CVD, as well as the current status and the most important results of their clinical trials.

Update on the laboratory investigation of dyslipidemias

The role of the clinical laboratory is evolving to provide more information to clinicians to assess cardiovascular disease (CVD) risk and target therapy more effectively. Current routine methods to measure LDL-cholesterol (LDL-C), the Friedewald calculation, ultracentrifugation, electrophoresis and homogeneous direct methods have established limitations. Studies suggest that LDL and HDL size or particle concentration are alternative methods to predict future CVD risk. At this time there is no consensus role for lipoprotein particle or subclasses in CVD risk assessment. LDL and HDL particle concentration are measured by several methods, namely gradient gel electrophoresis, ultracentrifugation-vertical auto profile, nuclear magnetic resonance and ion mobility. It has been suggested that HDL functional assays may be better predictors of CVD risk. To assess the issue of lipoprotein subclasses/particles and HDL function as potential CVD risk markers robust, simple, validated analytical methods are required. In patients with small dense LDL particles, even a perfect measure of LDL-C will not reflect LDL particle concentration. Non-HDL-C is an alternative measurement and includes VLDL and CM remnant cholesterol and LDL-C. However, apolipoprotein B measurement may more accurately reflect LDL particle numbers. Non-fasting lipid measurements have many practical advantages. Defining thresholds for treatment with new measurements of CVD risk remain a challenge. In families with genetic variants, ApoCIII and lipoprotein (a) may be additional risk factors. Recognition of familial causes of dyslipidemias and diagnosis in childhood will result in early treatment. This review discusses the limitations in current laboratory technologies to predict CVD risk and reviews the evidence for emergent approaches using newer biomarkers in clinical practice.

Why Is Apolipoprotein CIII Emerging as a Novel Therapeutic Target to Reduce the Burden of Cardiovascular Disease?

ApoC-III was discovered almost 50 years ago, but for many years, it did not attract much attention. However, as epidemiological and Mendelian randomization studies have associated apoC-III with low levels of triglycerides and decreased incidence of cardiovascular disease (CVD), it has emerged as a novel and potentially powerful therapeutic approach to managing dyslipidemia and CVD risk. The atherogenicity of apoC-III has been attributed to both direct lipoprotein lipase-mediated mechanisms and indirect mechanisms, such as promoting secretion of triglyceride-rich lipoproteins (TRLs), provoking proinflammatory responses in vascular cells and impairing LPL-independent hepatic clearance of TRL remnants. Encouraging results from clinical trials using antisense oligonucleotide, which selectively inhibits apoC-III, indicate that modulating apoC-III may be a potent therapeutic approach to managing dyslipidemia and cardiovascular disease risk.

Apolipoprotein C-III Levels and Incident Coronary Artery Disease Risk: The EPIC-Norfolk Prospective Population Study

OBJECTIVE

Apolipoprotein C-III (apoC-III) is a key regulator of triglyceride metabolism. Elevated triglyceride-rich lipoproteins and apoC-III levels are causally linked to coronary artery disease (CAD) risk. The mechanism(s) through which apoC-III increases CAD risk remains largely unknown. The aim was to confirm the association between apoC-III plasma levels and CAD risk and to explore which lipoprotein subfractions contribute to this relationship between apoC-III and CAD risk.

APPROACH AND RESULTS

Plasma apoC-III levels were measured in baseline samples from a nested case-control study in the European Prospective Investigation of Cancer (EPIC)-Norfolk study. The study comprised 2711 apparently healthy study participants, of whom 832 subsequently developed CAD. We studied the association of baseline apoC-III levels with incident CAD risk, lipoprotein subfractions measured by nuclear magnetic resonance spectroscopy and inflammatory biomarkers. ApoC-III levels were significantly associated with CAD risk (odds ratio, 1.91; 95% confidence interval, 1.48-2.48 for highest compared with lowest quintile), retaining significance after adjustment for traditional CAD risk factors (odds ratio, 1.47; 95% confidence interval, 1.11-1.94). ApoC-III levels were positively correlated with triglyceride levels, (r=0.39), particle numbers of very-low-density lipoprotein (r=0.25), intermediate-density lipoprotein (r=0.23), small dense low-density lipoprotein (r=0.26), and high-sensitivity C-reactive protein (r=0.15), whereas an inverse correlation was observed with large low-density lipoprotein particle number (r=-0.11), P<0.001 for each. Mediation analysis indicated that the association between apoC-III and CAD risk could be explained by triglyceride elevation (triglyceride, very-low-density lipoprotein, and intermediate-density lipoprotein particles), small low-density lipoprotein particle size, and high-sensitivity C-reactive protein.

CONCLUSIONS

ApoC-III levels are significantly associated with incident CAD risk. Elevated levels of remnant lipoproteins, small dense low-density lipoprotein, and low-grade inflammation may explain this association.

The emerging role of apolipoprotein C-III: beyond effects on triglyceride metabolism

Apolipoprotein C-III has been referred to as an important participant in the metabolism of triglyceride-rich lipoproteins, leading to hypertriglyceridemia and thereafter cardiovascular disease. Accumulating evidence indicates that apolipoprotein C-III is a multifaceted protein which not only regulates triglyceride metabolism, but also participates in the atherosclerotic lesion formation and several other pathological processes involved in atherosclerosis. Based on data from experiments and clinical trials, some novel therapies such as antisense technology emerge.

Correlation between Serum Lipid Levels and Measured Glomerular Filtration Rate in Chinese Patients with Chronic Kidney Disease

Introduction

Dyslipidemia is often detected in patients with chronic kidney disease (CKD). Previous studies of the relationship between lipid profiles and kidney function have yielded variable results. We aimed to investigate the correlation between serum lipid levels and kidney function evaluated by measured glomerular filtration rate (mGFR) in Chinese patients with CKD.

Methods

A cross-sectional study was conducted on 2036 Chinese CKD patients who had mGFR. Linear regression analysis was performed to evaluate the correlation between different serum lipid levels and mGFR, while logistic regression analysis was used to investigate the association between CKD stages and the risk of different types of dyslipidemia.

Results

The mean age was 55 years and the mean mGFR was 63 mL/min/1.73m². After adjusting for some confounders (age, gender, body mass index, a history of diabetes, fasting glucose, a history of hypertension, systolic blood pressure, diastolic blood pressure, smoking status, hemoglobin, serum potassium, serum albumin, and serum uric acid), serum triglyceride level showed a negative correlation with mGFR (β = -0.006, P = 0.006) in linear regression analysis, and CKD stages were positively related to the risk of hypertriglyceridemia (odds ratios were 1.329, 1.868, 2.514 and P were 0.046, < 0.001, < 0.001 for CKD stage 2, 3, 4/5, respectively) in logistic regression anlysis.

Conclusions

Serum triglyceride level is independently association with mGFR. Patients with reduced kidney function are more likely to have higher serum triglyceride levels. Further longitudinal, multicenter and well-conducted studies are needed to provide more evidence.

The association of HDL-apoCIII with coronary heart disease and the effect of statin treatment on it

Background

Apolipoprotein CIII (apoCIII) is considered to impair the anti-atherogenic effect of high density lipoprotein (HDL) in coronary heart disease (CHD) patients, and apoCIII content in HDL (HDL-apoCIII) predicts CHD more accurately. However, the relationship between HDL-apoCIII and CHD, and the effect of statin treatment on HDL-apoCIII are still unclear. The aims of the study are to establish the association of HDL-apoCIII with CHD, and investigate the effect of statin treatment on HDL-apoCIII in CHD patients.

Methods

We conducted a hospital-based observational study. Totally 80 non-CHD patients and 120 CHD patients without statin treatment were previously enrolled in this study. All the CHD patients received statin treatment, and 63 of them were followed after 3 months of regular statin treatment. HDL sample of each patient was isolated by density gradient ultracentrifugation from fasting venous plasma, and HDL-apoCIII of each patient was measured by ELISA method.

Results

HDL-apoCIII was significantly higher in CHD patients than non-CHD patients (p < 0.05), and it was still an independent predictor of CHD after adjusting for other factors. Total plasma apoCIII, especially HDL-apoCIII was significantly elevated after statin treatment in CHD patients, whereas total cholesterol (TC), low density lipoprotein cholesterol (LDL-c) and apolipoprotein B (apoB) were decreased significantly (p < 0.05). Compared with CHD patients without diabetes mellitus (DM), the effect of statin treatment on apoCIII markers was minor in CHD patients with DM. And HDL-apoCIII correlated with plasma TG significantly in non-CHD and CHD patients (p < 0.05), but the correlation in CHD patients did not exist after statin treatment (p > 0.05).

Conclusions

HDL-apoCIII has a significant and positive association with CHD. Although conventional atherogenic lipid markers have a significantly decrease in CHD patients after statin treatment, HDL-apoCIII has a further elevation at the same time.

Electronic supplementary material

The online version of this article (doi:10.1186/s12944-015-0129-8) contains supplementary material, which is available to authorized users.

Effects of pitavastatin on the expression of VCAM-1 and its target gene miR-126 in cultured human umbilical vein endothelial cells

OBJECTIVES

Reducing the expression of endothelial cell adhesion molecules is conducive to the decrease of inflammation-induced vascular complications. In this study, we observed pitavastatin on expression of vascular cell adhesion molecule-1 (VCAM-1) and its influence on VCAM-1's target gene miR-126 in endothelial cells. The purpose of this study is to explore the mechanism of pitavastatin in prevention and treatment of atherosclerosis.

METHODS

HUVEC were cultured in M1640 and passages 2-5 were used in experiments. The cells were randomly divided into three groups, control, TNF-α and pitavastatin group. Cells of TNF-α group were co-incubated with different concentrations (10, 20, 30 μg/L) of TNF-α for 24 h. Cells of pitavastatin group were firstly coincubated with (0.01, 0.1, 1 μmol/L) pitavastatin, respectively, for 1 h, then coincubated with 30 μg/L TNF-α for 24 h. VCAM-1 and miR-126 mRNA were detected by RT-PCR, and Western blotting was used to detect protein expression of VCAM-1.

RESULTS

Both detection methods have showed that TNF-α stimulation significantly increased the mRNA and protein expression of VCAM-1 in a dose-dependent manner, and miR-126 mRNA expression exhibited a decreasing trend. The increase of VCAM-1 mRNA and protein expression induced by TNF-α was inhibited by pitavastatin in a dose-dependent manner, too. However, there were no differences of the expression of miR-126 among three groups.

CONCLUSIONS

These effects may explain the ability of pitavastatin to reduce the progression of atherosclerosis. The findings further suggest that inhibitory effect of pitavastatin on VCAM-1 is not related to miR-126 but depends on other ways.

Protein biomarkers for the prediction of cardiovascular disease in type 2 diabetes

AIMS/HYPOTHESIS

We selected the most informative protein biomarkers for the prediction of incident cardiovascular disease (CVD) in people with type 2 diabetes.

METHODS

In this nested case-control study we measured 42 candidate CVD biomarkers in 1,123 incident CVD cases and 1,187 controls with type 2 diabetes selected from five European centres. Combinations of biomarkers were selected using cross-validated logistic regression models. Model prediction was assessed using the area under the receiver operating characteristic curve (AUROC).

RESULTS

Sixteen biomarkers showed univariate associations with incident CVD. The most predictive subset selected by forward selection methods contained six biomarkers: N-terminal pro-B-type natriuretic peptide (OR 1.69 per 1 SD, 95% CI 1.47, 1.95), high-sensitivity troponin T (OR 1.29, 95% CI 1.11, 1.51), IL-6 (OR 1.13, 95% CI 1.02, 1.25), IL-15 (OR 1.15, 95% CI 1.01, 1.31), apolipoprotein C-III (OR 0.79, 95% CI 0.70, 0.88) and soluble receptor for AGE (OR 0.84, 95% CI 0.76, 0.94). The prediction of CVD beyond clinical covariates improved from an AUROC of 0.66 to 0.72 (AUROC for Framingham Risk Score covariates 0.59). In addition to the biomarkers, the most important clinical covariates for improving prediction beyond the Framingham covariates were estimated GFR, insulin therapy and HbA1c.

CONCLUSIONS/INTERPRETATION

We identified six protein biomarkers that in combination with clinical covariates improved the prediction of our model beyond the Framingham Score covariates. Biomarkers can contribute to improved prediction of CVD in diabetes but clinical data including measures of renal function and diabetes-specific factors not included in the Framingham Risk Score are also needed.

The risk of cardiovascular events with increased apolipoprotein CIII: A systematic review and meta-analysis

BACKGROUND

Apolipoprotein CIII (apoC-III) is an atherogenic protein found on HDL, VLDL and LDL.

OBJECTIVE

The objective of this study is to review the literature on the association of blood apoC-III level with cardiovascular events and the dose-response relationship for this association.

METHODS AND RESULTS

MEDLINE, EMBASE, BIOSIS, CINAHL, Clinicaltrials.gov, grey-literature sources, contact with investigators, and reference lists of studies, without language restrictions, were reviewed. Twelve studies (5 retrospective and 7 prospective) with a total of 3163 cases of cardiovascular events met inclusion criteria for this systematic review. The pooled standardized mean difference showed significantly higher levels of apoC-III in the non-HDL fraction of plasma (representing apoC-III in VLDL and LDL) in those with cardiovascular disease compared with controls; no difference for apoC-III levels in HDL; and, a trend toward higher total plasma apoC-III in the cases. Pooled risk estimates from the meta-analysis were 2.48 (1.48-4.32; non-HDL apoC-III), 1.09 (0.65-1.82; HDL apoC-III), and 1.33 (1.07-1.66; total apoC-III) for a cardiovascular event with a 5-mg/dL increase in apoC-III.

CONCLUSIONS

The current body of literature includes several methodologically sound studies that together provide consistent evidence for an association of cardiovascular events with blood apoC-III level in total plasma or in VLDL and LDL. More data are needed to determine importance of levels of apoC-III in specific lipoproteins for cardiovascular risk assessment and management and to elucidate the interaction between triglycerides and apoC-III in relation to risk of cardiovascular disease.

Dose-response effects of marine omega-3 fatty acids on apolipoproteins, apolipoprotein-defined lipoprotein subclasses, and Lp-PLA2 in individuals with moderate hypertriglyceridemia

BACKGROUND

Apolipoprotein (apo) distribution and lipoprotein (Lp)-associated markers of inflammation, such as lipoprotein-associated phospholipase A2 (Lp-PLA2), influence the atherogenicity of circulating lipids and lipoproteins. Little evidence exists regarding the dose-response effects of the marine omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) on apos, apo-defined Lps, and Lp-PLA2.

OBJECTIVE

The purpose of this study was to compare the effects of 0, 0.85, and 3.4 g/d of EPA + DHA on Lp-PLA2 mass and activity in individuals with moderate hypertriglyceridemia. We also measured effects on concentrations of apoAI, apoAII, apoB, apoC, apoD, and apoE-defined Lp subclasses.

METHODS

The study was a randomized, doubleblind, crossover design with 8-week treatment periods and 6-week washout periods. During the 3 treatment periods, subjects (n = 25) received 0 g/d EPA + DHA, 0.85 g/d EPA + DHA (low dose), and 3.4 g/d EPA + DHA (high dose) in random order.

RESULTS

apoB and apoC-III were significantly decreased by the high dose relative to placebo and low dose (P < .01), as was very low-density lipoprotein cholesterol (P < .005). The low dose had no effect on Lp outcomes compared with placebo. The high- and low-dose effects differed significantly for heparin-precipitated apoC-III, LpB, LpA-I, and apoB/apoA-I ratio (P < .05). There was a trend for a decreased Lp-PLA2 mass with the high dose (P = .1).

CONCLUSION

The effects of 3.4 g/d EPA + DHA on apoB and apoC-III may reduce atherosclerotic plaque progression in individuals with elevated triglycerides.

Determinants of VLDL composition and apo B-containing particles in familial combined hyperlipidemia

BACKGROUND

In familial combined hyperlipidemia (FCHL) the severity of the dyslipidemia is determined by an overproduction of VLDL (very low density lipoprotein) particles and by its abnormal lipid composition. However, few are known regarding the metabolic factors that determine these abnormalities. We investigated the impact of metabolic factors on the number of atherogenic particles (apolipoprotein B level (apoB)) and the triglyceride content of very low-density lipoproteins (VLDLs-TG).

METHODS

A cross-sectional study done in FCHL subjects and gender and age-matched healthy subjects. A clinical assessment, lipid profile and plasma concentrations of insulin, apolipoprotein CIII (apo CIII), apolipoprotein AII (apo AII), high sensitive C-reactive protein (HS-CRP), adiponectin and leptin were documented in 147 FCHL patients and 147 age-matched healthy subjects. Multivariate regression models were performed to investigate the independent determinants of VLDL-TG and apo B levels adjusting for confounding factors.

RESULTS

The variables that determined the VLDL-triglyceride content as a surrogate of VLDL composition were apo CIII (β=0.365, p<0.001), insulin (β=0.281, p<0.001), Apo AII (β=0.145, p<0.035), and adiponectin levels (β=-0.255, p<0.001). This model explained 34% of VLDL composition (VLDL-TG) variability. However, none of these variables were independent contributors of apo B-containing particles.

CONCLUSIONS

In patients with FCHL apo CIII, apo AII and adiponectin are major novel factors determining the VLDL particle composition. However, such factors do not explain apo B-containing particles.

Dual PPAR α / γ Agonism Normalizes Lipoprotein Profile of Renal Dyslipidemia

Chronic kidney disease (CKD) is characterised by specific lipoprotein abnormalities and insulin resistance. Dual activation of the peroxisome proliferators-activated receptors (PPAR) α and γ can significantly improve insulin sensitivity. The aim of the study was to investigate the effects of a dual PPAR α / γ agonist on lipoprotein abnormalities in patients with CKD. One mg of the dual PPAR α / γ agonist tesaglitazar was given once daily during six weeks to CKD patients, and to healthy subjects. Plasma lipids, apolipoproteins (apo) and discrete lipoprotein subclasses were measured at baseline and end of treatment. In the CKD patients apoA-I increased significantly by 9%, and apoB decreased by 18%. There was an increase of apoC-III in HDL by 30%, and a parallel decrease of apoC-III in VLDL + LDL by 13%. Both the apoB-containing cholesterol-rich and the triglyceride-rich subclasses decreased significantly. With the exception of ApoC-III,all plasma lipids apolipoproteins and lipoprotein subclasses were reduced by treatment down to similar levels as the baseline levels of a healthy group of reference subjects. This study suggests that by improving insulin sensitivity a dual PPAR α / γ agonist has the potential to normalise most of the lipoprotein abnormalities in patients with CKD.

Modulation of lipoprotein metabolism by antisense technology: preclinical drug discovery methodology

Antisense oligonucleotides (ASOs) are a new class of specific therapeutic agents that alter the intermediary metabolism of mRNA, resulting in the suppression of disease-associated gene products. ASOs exert their pharmacological effects after hybridizing, via Watson-Crick base pairing, to a specific target RNA. If appropriately designed, this event results in the recruitment of RNase H, the degradation of targeted mRNA or pre-mRNA, and subsequent inhibition of the synthesis of a specific protein. A key advantage of the technology is the ability to selectively inhibit targets that cannot be modulated by traditional therapeutics such as structural proteins, transcription factors, and, of topical interest, lipoproteins. In this chapter, we will first provide an overview of antisense technology, then more specifically describe the status of lipoprotein-related genes that have been studied using the antisense platform, and finally, outline the general methodology required to design and evaluate the in vitro and in vivo efficacy of those drugs.

Statins suppress apolipoprotein CIII-induced vascular endothelial cell activation and monocyte adhesion

Aims

Activation of vascular endothelial cells (ECs) contributes importantly to inflammation and atherogenesis. We previously reported that apolipoprotein CIII (apoCIII), found abundantly on circulating triglyceride-rich lipoproteins, enhances adhesion of human monocytes to ECs in vitro. Statins may exert lipid-independent anti-inflammatory effects. The present study examined whether statins suppress apoCIII-induced EC activation in vitro and in vivo.

Methods and results

Physiologically relevant concentrations of purified human apoCIII enhanced attachment of the monocyte-like cell line THP-1 to human saphenous vein ECs (HSVECs) or human coronary artery ECs (HCAECs) under both static and laminar shear stress conditions. This process mainly depends on vascular cell adhesion molecule-1 (VCAM-1), as a blocking VCAM-1 antibody abolished apoCIII-induced monocyte adhesion. ApoCIII significantly increased VCAM-1 expression in HSVECs and HCAECs. Pre-treatment with statins suppressed apoCIII-induced VCAM-1 expression and monocyte adhesion, with two lipophilic statins (pitavastatin and atorvastatin) exhibiting inhibitory effects at lower concentration than those of hydrophilic pravastatin. Nuclear factor κB (NF-κB) mediated apoCIII-induced VCAM-1 expression, as demonstrated via loss-of-function experiments, and pitavastatin treatment suppressed NF-κB activation. Furthermore, in the aorta of hypercholesterolaemic Ldlr^−/− mice, pitavastatin administration in vivo suppressed VCAM-1 mRNA and protein, induced by apoCIII bolus injection. Similarly, in a subcutaneous dorsal air pouch mouse model of leucocyte recruitment, apoCIII injection induced F4/80+ monocyte and macrophage accumulation, whereas pitavastatin administration reduced this effect.

Conclusions

These findings further establish the direct role of apoCIII in atherogenesis and suggest that anti-inflammatory effects of statins could improve vascular disease in the population with elevated plasma apoCIII.

[Influence of non-alcoholic fatty liver disease on cardiovascular disease]

Non-alcoholic fatty liver disease encompasses a spectrum ranging from simple steatosis to steatohepatitis without excess alcohol intake and is considered to be the hepatic manifestation of metabolic syndrome. Recent studies indicate that non-alcoholic fatty liver disease is closely related to cardiovascular disease, especially to thickening of the intima-media layer of the carotid artery, as the morphostructural manifestation of the presence of subclinical atheromatosis. Therefore, the correct management of non-alcoholic fatty liver disease would allow the natural history of both the liver disease and the atherosclerosis to be modified.

Dietary inclusion of salmon, herring and pompano as oily fish reduces CVD risk markers in dyslipidaemic middle-aged and elderly Chinese women

Dietary intervention studies to assess the cardioprotective effects of oily fish are scarce in China. The present study aimed to examine the effects of the oily fish, Norwegian salmon, herring and local farmed pompano (Trachinotus ovatus) on CVD risk markers when included in the Chinese diet. In this 8-week, parallel-arm, randomised intervention study, 126 Chinese women with hypertriacylglycerolaemia, aged 35-70 years, were assigned to four groups to consume an experimental lunch containing 80 g fillets of either one of three oily fish or a mix of commonly eaten meats (pork/chicken/beef/lean fish) for 5 d/week. The results showed that inclusion of the three oily fish significantly increased the intake of n-3 long-chain PUFA (LC-PUFA) while decreasing the dietary n-6:n-3 PUFA ratio. Compared to the control group, significant increases of DHA, EPA+DHA and total n-3 PUFA in plasma choline phosphoglyceride were observed in the three oily fish groups. Plasma TAG levels were significantly reduced only in the salmon and herring groups. When compared to the baseline level, the three oily fish diets significantly decreased serum concentrations of TAG, apoB, apoCII and apoCIII, but only the salmon and herring diets significantly lowered TNF-α and raised adiponectin levels in serum. The salmon diet additionally decreased the serum concentration of IL-6. To conclude, dietary inclusion of salmon, herring and pompano as oily fish can effectively increase serum n-3 LC-PUFA content and are associated with favourable biochemical changes in dyslipidaemic middle-aged and elderly Chinese women, and these beneficial effects are mainly associated with n-3 LC-PUFA contents.

Lack of association between apolipoprotein C3 gene polymorphisms and risk of coronary heart disease in a Han population in East China

Background

Several polymorphisms in the apolipoprotein C3 (APOC3) gene have been found association with hypertriglyceridemia(HTG), but the link with coronary heart disease(CHD) risk between ethnicities was still controversial. Among them, reseachers paid more attentions to the promoter polymorphisms T-455C and C-482T because both of them located in insulin-responsive element (IRE) and insulin was thought to exert its action by down-regulating APOC3 gene expression. The aim of this study was to investigate the association of the two polymorphisms of APOC3 with CHD in a Han population in East China.

Methods

TaqMan SNP Genotyping Assays were carried out to detect the genotypes of APOC3 gene, including the T-455C and C-482T, in 286 subjects with CHD and 325 controls without CHD. The levels of serum lipid profiles were also detected by biochemical methods.

Results

There was no difference of genotype frequencies and allele frequencies between the CHD population and the controls(P > 0.05). Compared with the most common genotype -455TT or -482CC, the variants had neither significantly increased CHD risk, nor the lipid variables showed any statistically relevant differences in the research population. The adjusted OR of CHD were 5.67 [0.27-18.74] and 0.75 [0.20-2.73] in carriers of the APOC3 -455C and -482T variants, respectively(P > 0.05). There was also no significant difference in APOC3 haplotype distribution in CHD and controls, but there was a strong linkage disequilibrium between T-455C and C-482T with D' = 0.9293, 0.8881, respectively(P < 0.0001).

Conclusions

Our data did not support a relationship between the two polymorphisms of APOC3 gene and risk of CHD in the Han population in East China.

Lipoprotein abnormalities in patients with atherosclerotic renovascular disease

BACKGROUND

Patients with atherosclerotic renovascular disease (ARVD) have a high risk of cardiovascular death. The primary aim was to characterize abnormalities in apolipoprotein (Apo)-defined lipoprotein (Lp) subclasses in patients with ARVD.

METHODS

Baseline measurements were performed on 42 patients with ARVD 4 weeks after renal angioplasty (PTRA). All patients were on statin treatment. Twenty age-matched healthy subjects without medications served as controls. Subsequently, patients were randomized to treatment with either candesartan (n = 21), or antihypertensive treatment without inhibitors of the renin-angiotensin-aldosterone system (n = 21) and followed for 11 months.

RESULTS

At baseline, ApoC-III (12.7 ± 4.6 vs. 8.8 ± 2.6 (SD) mg/dl, p < 0.05), LpB:C:E (13.3 ± 5.4 vs. 8.4 ± 4.3 mg/dl, p < 0.05), and the sum of ApoC-III-containing lipoproteins, i.e. LpB:C + LpB:C:E + LpA-II:B:C:D:E (46 ± 15 vs. 37 ± 8 mg/dl, p < 0.05), were significantly elevated in ARVD patients versus healthy controls. Multiple regression analyses showed that only plasma renin activity was independently associated with ApoC-III levels at baseline (p < 0.05, r = 0.74). Treatment with candesartan did not correct abnormalities.

CONCLUSIONS

Patients with ARVD treated with statins have an atherogenic lipoprotein profile characterized by elevated levels of ApoC-III-containing, triglyceride-rich lipoproteins that could accelerate atherosclerotic disease.

APOC3 -482C>T polymorphism, circulating apolipoprotein C-III and smoking: interrelation and roles in predicting type-2 diabetes and coronary disease

OBJECTIVES

We determined the relationship of smoking status on APOC3 -482C>T polymorphism and apolipoprotein C-III (apoC-III) concentrations and the latter two parameters' influence on risk of diabetes and coronary heart disease (CHD).

DESIGN AND METHODS

Prediction of incident cases was assessed at 5.5years' follow-up in unselected 519 individuals of a general population genotyped for -482C>T polymorphism.

RESULTS

Female sex and current smoking were significantly associated with low circulating apoC-III in subjects without (p≤0.033) than with abdominal obesity (p=0.053) or than insulin resistant -482TT homozygotes (p=0.034) who had 20-30% higher serum apoC-III. Multi-adjusted serum apoC-III was log-linearly associated with fasting triglycerides. ApoC-III levels determined the development of diabetes [RR 1.56 (95%CI 1.21; 2.01)] and CHD [RR 1.38 (1.10; 1.72) for an increment of 14%], after adjustment for confounders.

CONCLUSION

APOC3 -482TT genotype is associated with high apoC-III concentrations only in the presence of abdominal obesity or insulin resistance, but not in current smokers who remain lean or insulin-sensitive. Rather than APOC3 -482C>T polymorphism, circulating apoC-III determines cardiometabolic risk.

Exenatide suppresses postprandial elevations in lipids and lipoproteins in individuals with impaired glucose tolerance and recent onset type 2 diabetes mellitus

OBJECTIVE

Chronic exenatide treatment in type 2 diabetes is associated with improved glucose control and fasting lipid levels, as well as weight loss. Less established is whether exenatide directly reduces postprandial lipid and lipoprotein levels without the reduction in body weight or fasting glucose and triglycerides levels that frequently occur with prolonged therapy. Therefore, the effect of a single injection of exenatide on postprandial lipids, remnant lipoproteins, and apolipoproteins was studied.

METHODS

A double-blinded, randomized, placebo-controlled, crossover study was conducted in 35 subjects (31 men and 4 women) with impaired glucose tolerance (n=20) or recent onset type 2 diabetes (n=15). A single subcutaneous injection of exenatide (10 microg) or normal saline was administered just prior to a high-calorie, fat-enriched breakfast meal. Concentrations of triglycerides (TG), apolipoproteins B-48 and CIII, non-esterified fatty acids (NEFA), and remnant lipoprotein (RLP) cholesterol and TG in serum or plasma were measured prior to the injection and for up to 8 h postprandially.

RESULTS

Exenatide markedly reduced postprandial elevation of TG, apolipoproteins B-48 and CIII, RLP-cholesterol and RLP-triglyceride (all p<0.001). Postprandial declines in NEFA were less pronounced but persisted longer with exenatide compared to placebo (p<0.05). These effects of exenatide were not affected either by glucose tolerance status or by treatment with statins.

CONCLUSION

These results demonstrate that exenatide acutely and profoundly inhibits postprandial excursions of proatherogenic lipids and lipoproteins and may offer additional cardiovascular risk reduction (NCT00974272).

Apolipoprotein C-III predicts cardiovascular mortality in severe coronary artery disease and is associated with an enhanced plasma thrombin generation

BACKGROUND

Apolipopoprotein C-III (apo C-III) plays a pivotal role in controlling plasma triglyceride (TG) and contributes to the atherogenic properties of TG-rich lipoproteins.

OBJECTIVES

(i) To examine the predictive value of serum apo C-III for cardiovascular mortality in the setting of secondary prevention of coronary artery disease (CAD); and (ii) to evaluate possible associations between apolipoprotein levels and the thrombin generation assay, a global test to estimate plasma thrombogenic potential.

METHODS AND RESULTS

A cohort of 633 patients with angiographically proven CAD was prospectively followed for a median follow-up of 57 months. The large majority of them (92%) underwent coronary (endovascular or surgical) revascularization. During the follow-up, 91 (14.3%) out of 633 patients died, with 64 events (10.1%) attributed to cardiovascular causes. After adjustment for all the other predictors of mortality during univariate analysis (i.e. age, statin therapy, myocardial infarction history, diabetes, hs-CRP and creatinine), elevated apo C-III levels (> or = 10.5 mg dL(-1)- the median value) significantly predicted both total and cardiovascular mortality (HR for total mortality 2.22 with 95% CI 1.16-4.24; HR for cardiovascular mortality 2.35 with 95% CI 1.19-4.62). In a subgroup of 225 subjects, apo C-III levels were significantly associated with endogenous thrombin potential in regression models (standardized beta coefficient = 0.207, P = 0.002).

CONCLUSIONS

Basal concentrations of apo C-III levels > or = 10.5 mg dL(-1) in CAD patients independently predicted cardiovascular mortality during the subsequent 5-year period. Such concentrations were associated with an enhanced plasma endogenous thrombin generation, suggesting a complex interplay between TG-rich particles and the coagulation cascade as well as a new 'thrombogenetic' role for apo C-III.