Effects of omega-3 carboxylic acids on lipoprotein particles and other cardiovascular risk markers in high-risk statin-treated patients with residual hypertriglyceridemia: a randomized, controlled, double-blind trial

Association between apolipoprotein C-III levels and coronary calcification detected by intravascular ultrasound in patients who underwent percutaneous coronary intervention

There are few reports on the association between apolipoprotein C-III (ApoC-III) and coronary calcification using intravascular modalities. This study aimed to investigate the impacts of ApoC-III levels on coronary calcification using grayscale intravascular ultrasound (IVUS). Consecutive 263 culprit lesions for 202 patients who underwent percutaneous coronary intervention using grayscale IVUS were included in this study and divided into four groups based on quartile ApoC-III values. This study assessed plaque characteristics, including severe calcification (>180° arc) at the minimum lumen area site and presence of calcified nodules within the culprit lesion using grayscale IVUS, and evaluated whether ApoC-III levels were associated with coronary calcified plaques. The highest ApoC-III quartile [Quartile 4 (Q4)] had a higher proportion of complex lesions, calcified plaques, severe calcification, calcified nodules, plaque burden, and total atheroma volume than the lowest ApoC-III quartile [Quartile 1 (Q1)]. Additionally, multivariable logistic regression analysis showed that Q4 was significantly associated with severe calcification and calcified nodules, with Q1 as the reference (odds ratio [OR]: 2.70, 95% confidence intervals [CIs]: 1.04-7.00, p = 0.042; and OR: 3.72, 95% CIs 1.26-11.0, p = 0.017, respectively). Furthermore, ApoC-III level (1-mg/dl increase) was a strong significant predictor of severe calcification (OR: 1.07, 95% CIs: 1.00-1.15, p = 0.040) and calcified nodules (OR: 1.09, 95% CIs: 1.01-1.19, p = 0.034) according to the multivariable logistic regression analysis. This study is the first to verify that elevated ApoC-III levels are associated with the development of severe calcification and progression to calcified nodules as detected by grayscale IVUS.

Effects of niacin and omega-3 fatty acids on HDL-apolipoprotein A-I exchange in subjects with metabolic syndrome

HDL-apolipoprotein A-I exchange (HAE) measures a functional property associated with HDL's ability to mediate reverse cholesterol transport. HAE has been used to examine HDL function in case-control studies but not in studies of therapeutics that alter HDL particle composition. This study investigates whether niacin and omega-3 fatty acids induce measurable changes in HAE using a cohort of fifty-six subjects with metabolic syndrome (MetS) who were previously recruited to a double-blind trial where they were randomized to 16 weeks of treatment with dual placebo, extended-release niacin (ERN, 2g/day), prescription omega-3 ethyl esters (P-OM3, 4g/day), or the combination. HAE was assessed at the beginning and end of the study. Compared to placebo, ERN and P-OM3 alone significantly increased HAE by 15.1% [8.2, 22.0] (P<0.0001) and 11.1% [4.5, 17.7] (P<0.0005), respectively, while in combination they increased HAE by 10.0% [2.5, 15.8] (P = 0.005). When HAE was evaluated per unit mass of apoA-I ERN increased apoA-I specific exchange activity by 20% (2, 41 CI, P = 0.02) and P-OM3 by 28% (9.6, 48 CI, P<0.0006). However the combination had no statistically significant effect, 10% (-9, 31 CI, P = 0.39). With regard to P-OM3 therapy in particular, the HAE assay detected an increase in this property in the absence of a concomitant rise in HDL-C and apoA-I levels, suggesting that the assay can detect functional changes in HDL that occur in the absence of traditional biomarkers.

Eicosapentaenoic acid vs. docosahexaenoic acid for the prevention of cardiovascular disease

PURPOSE OF REVIEW

Populations with greater fatty fish intake have lower risk of coronary heart disease. However, trials testing omega-3 fatty acids (FA) on cardiovascular outcomes have yielded inconsistent results. In this review, we summarize the major cardiovascular trials examining omega-3 FA supplementation, and compare differences with eicosapentaenoic acid (EPA) alone vs. docosahexaenoic acid (DHA) combined with EPA.

RECENT FINDINGS

The JELIS and REDUCE-IT trials both demonstrated significant reduction in cardiovascular events with high dose EPA in the form of icosapent ethyl (IPE), with a similar trend seen in the RESPECT-EPA trial. In contrast, the ASCEND, VITAL, STRENGTH, and OMEMI trials examining EPA+DPA combinations failed to demonstrate benefit. Beyond the difference in omega-3 FA formulations (IPE vs. omega-3 carboxylic acid), other differences between REDUCE-IT and STRENGTH include the achieved EPA levels, differing properties that EPA and DHA have on membrane stabilization, and the comparator oils tested in the trials.

SUMMARY

The totality of evidence suggests EPA alone, administered in a highly-purified, high-dose form, improves cardiovascular outcomes among patients with elevated triglycerides at high cardiovascular risk, but EPA and DHA together does not. Current guidelines endorse the use of IPE in statin-treated patients at high cardiovascular risk who have triglycerides >135 mg/dl.

Effect of N-3 Polyunsaturated Fatty Acids on Lipid Composition in Familial Hypercholesterolemia: A Randomized Crossover Trial

Individuals with familial hypercholesterolemia (FH) have an increased risk of cardiovascular disease. Treatment is mainly low-density lipoprotein cholesterol (LDL-C) reduction. How omega-3 polyunsaturated fatty acids (n-3 PUFAs) supplements affect lipoproteins in FH subjects is unknown. We hypothesized that a high-dose n-3 PUFA supplement would reduce atherogenic lipoproteins and influence the high-density lipoprotein cholesterol (HDL-C) function. We performed a randomized, double-blinded crossover study with 34 genetically verified FH individuals (18−75 years, clinically stable, statin treatment > 12 months). Treatment was 4 g n-3 PUFAs (1840 mg eicosapentaenoic acid and 1520 mg docosahexaenoic acid daily) or four capsules of olive oil for three months in a crossover design with a washout period of three months. The defined outcomes were changes in triglycerides, lipoproteins, lipoprotein subfractions, apolipoproteins, and HDL-C function. After treatment with n-3 PUFAs, total cholesterol, LDL-C, and triglycerides were reduced compared to placebo (p ≤ 0.01 for all). Total HDL-C levels were unchanged, but the subfraction of large HDL-C was higher (p ≤ 0.0001) after n-3 PUFAs than after placebo, and intermediate HDL-C and small HDL-C were reduced after n-3 PUFAs compared to placebo (p = 0.02 and p ≤ 0.001, respectively). No changes were found in apolipoproteins and HDL-C function. N-3 PUFAs supplements reduced atherogenic lipoproteins in FH subjects, leaving HDL-C function unaffected.

Multimodality Imaging Trials Evaluating the Impact of Omega-3 Fatty Acids on Coronary Artery Plaque Characteristics and Burden

Treatment of established risk factors, especially low-density lipoprotein (LDL) cholesterol, is the cornerstone of preventing atherosclerotic coronary artery disease. Despite reducing LDL cholesterol, there remains a significant risk of cardiovascular disease. Inflammatory and metabolic pathways contribute to recurrence of cardiovascular events, and are often missed in clinical practice. Eicosapentaenoic acid (EPA) may play a crucial role in reducing residual risk of cardiovascular disease. In this review we discuss the clinical applications of omega-3 fatty acids (OM3FAs), their mechanism of action, the difference between pure EPA and docosahexaenoic acid components, and the latest cardiovascular outcome trials and imaging trials evaluating coronary plaque. PubMed and EMBASE were searched to include all the remarkable clinical trials investigating OM3FAs and cardiovascular disease. Beyond statins, additional medications are required to reduce the risk of cardiovascular disease. EPA has shown cardiovascular benefit in addition to statins in large outcome trials. Additionally, multiple serial-imaging studies have demonstrated benefits on plaque progression and stabilization. Due to its pleotropic properties, icosapent ethyl outperforms other OM3FAs in decreasing cardiovascular disease risk in both patients with and without high triglycerides, and is currently recommended as an adjunct to statins. To further strengthen the current evidence, additional research is required to elucidate the inconsistencies between the effects of pure EPA and EPA plus docosahexaenoic acid.

Controversies in the Use of Omega-3 Fatty Acids to Prevent Atherosclerosis

PURPOSE OF REVIEW

We discuss current controversies in the clinical use of omega-3 fatty acids (FA), primarily eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), and examine discrepancies between recent trials. Furthermore, we discuss potential side effects reported in these studies and the role of mixed omega-3 FA dietary supplements and concerns about their use.

RECENT FINDINGS

REDUCE-IT showed that addition of icosapent ethyl, a highly purified form of EPA, can reduce risk of cardiovascular events among statin-treated individuals with high triglycerides. Additional supportive evidence for EPA has come from other trials and meta-analyses of omega-3 FA therapy. In contrast, trials of mixed EPA/DHA products have consistently failed to improve cardiovascular outcomes. Discrepancies in results reported in RCTs could be explained by differences in omega-3 FA products, dosing, study populations, and study designs including the placebo control formulation. Evidence obtained from highly purified forms should not be extrapolated to other mixed formulations, including "over-the-counter" omega-3 supplements. Targeting TG-rich lipoproteins represents a new frontier for mitigating ASCVD risk. Clinical and basic research evidence suggests that the use of omega-3 FA, specifically EPA, appears to slow atherosclerosis by reducing triglyceride-rich lipoproteins and/or inflammation, therefore addressing residual risk of clinical ASCVD.

Multimodality Imaging Trials Evaluating the Impact of Omega-3 Fatty Acids on Coronary Artery Plaque Characteristics and Burden

Treatment of established risk factors, especially low-density lipoprotein (LDL) cholesterol, is the cornerstone of preventing atherosclerotic coronary artery disease. Despite reducing LDL cholesterol, there remains a significant risk of cardiovascular disease. Inflammatory and metabolic pathways contribute to recurrence of cardiovascular events, and are often missed in clinical practice. Eicosapentaenoic acid (EPA) may play a crucial role in reducing residual risk of cardiovascular disease. In this review we discuss the clinical applications of omega-3 fatty acids (OM3FAs), their mechanism of action, the difference between pure EPA and docosahexaenoic acid components, and the latest cardiovascular outcome trials and imaging trials evaluating coronary plaque. PubMed and EMBASE were searched to include all the remarkable clinical trials investigating OM3FAs and cardiovascular disease. Beyond statins, additional medications are required to reduce the risk of cardiovascular disease. EPA has shown cardiovascular benefit in addition to statins in large outcome trials. Additionally, multiple serial-imaging studies have demonstrated benefits on plaque progression and stabilization. Due to its pleotropic properties, icosapent ethyl outperforms other OM3FAs in decreasing cardiovascular disease risk in both patients with and without high triglycerides, and is currently recommended as an adjunct to statins. To further strengthen the current evidence, additional research is required to elucidate the inconsistencies between the effects of pure EPA and EPA plus docosahexaenoic acid.

Adipose tissue macrophages and atherogenesis – a synergy with cholesterolaemia

Excessive LDL cholesterol concentration together with subclinical inflammation, in which macrophages play a central role, are linked pathologies. The process starts with the accumulation of macrophages in white adipose tissue and the switch of their polarization toward a pro-inflammatory phenotype. The proportion of pro-inflammatory macrophages in adipose tissue is related to the main risk predictors of cardiovascular disease. The cholesterol content of phospholipids of cell membranes seems to possess a crucial role in the regulation of membrane signal transduction and macrophage polarization. Also, different fatty acids of membrane phospholipids influence phenotypes of adipose tissue macrophages with saturated fatty acids stimulating pro-inflammatory whereas ω3 fatty acids anti-inflammatory changes. The inflammatory status of white adipose tissue, therefore, reflects not only adipose tissue volume but also adipose tissue macrophages feature. The beneficial dietary change leading to an atherogenic lipoprotein decrease may therefore synergically reduce adipose tissue driven inflammation.

Therapeutic potential of pro-resolving mediators in diabetic kidney disease

Renal microvascular disease associated with diabetes [Diabetic kidney disease - DKD] is the leading cause of chronic kidney disease. In DKD, glomerular basement membrane thickening, mesangial expansion, endothelial dysfunction, podocyte cell loss and renal tubule injury contribute to progressive glomerulosclerosis and tubulointerstitial fibrosis. Chronic inflammation is recognized as a major pathogenic mechanism for DKD, with resident and circulating immune cells interacting with local kidney cell populations to provoke an inflammatory response. The onset of inflammation is driven by the release of well described proinflammatory mediators, and this is typically followed by a resolution phase. Inflammation resolution is achieved through the bioactions of endogenous specialized pro-resolving lipid mediators (SPMs). As our understanding of SPMs advances 'resolution pharmacology' based approaches using these molecules are being explored in DKD.

Metabolism of Triglyceride-Rich Lipoproteins

Triglycerides are critical lipids as they provide an energy source that is both compact and efficient. Due to its hydrophobic nature triglyceride molecules can pack together densely and so be stored in adipose tissue. To be transported in the aqueous medium of plasma, triglycerides have to be incorporated into lipoprotein particles along with other components such as cholesterol, phospholipid and associated structural and regulatory apolipoproteins. Here we discuss the physiology of normal triglyceride metabolism, and how impaired metabolism induces hypertriglyceridemia and its pathogenic consequences including atherosclerosis. We also discuss established and novel therapies to reduce triglyceride-rich lipoproteins.

Omega-3 fatty acid blood levels are inversely associated with cardiometabolic risk factors in HFpEF patients: the Aldo-DHF randomized controlled trial

Objectives

To evaluate associations of omega-3 fatty acid (O3-FA) blood levels with cardiometabolic risk markers, functional capacity and cardiac function/morphology in patients with heart failure with preserved ejection fraction (HFpEF).

Background

O3-FA have been linked to reduced risk for HF and associated phenotypic traits in experimental/clinical studies.

Methods

This is a cross-sectional analysis of data from the Aldo-DHF-RCT. From 422 patients, the omega-3-index (O3I = EPA + DHA) was analyzed at baseline in n = 404 using the HS-Omega-3-Index^® methodology. Patient characteristics were; 67 ± 8 years, 53% female, NYHA II/III (87/13%), ejection fraction ≥ 50%, E/e′ 7.1 ± 1.5; median NT-proBNP 158 ng/L (IQR 82–298). Pearson’s correlation coefficient and multiple linear regression analyses, using sex and age as covariates, were used to describe associations of the O3I with metabolic phenotype, functional capacity, echocardiographic markers for LVDF, and neurohumoral activation at baseline/12 months.

Results

The O3I was below (< 8%), within (8–11%), and higher (> 11%) than the target range in 374 (93%), 29 (7%), and 1 (0.2%) patients, respectively. Mean O3I was 5.7 ± 1.7%. The O3I was inversely associated with HbA1c (r = − 0.139, p = 0.006), triglycerides-to-HDL-C ratio (r = − 0.12, p = 0.017), triglycerides (r = − 0.117, p = 0.02), non-HDL-C (r = − 0.101, p = 0.044), body-mass-index (r = − 0.149, p = 0.003), waist circumference (r = − 0.121, p = 0.015), waist-to-height ratio (r = − 0.141, p = 0.005), and positively associated with submaximal aerobic capacity (r = 0.113, p = 0.023) and LVEF (r = 0.211, p < 0.001) at baseline. Higher O3I at baseline was predictive of submaximal aerobic capacity (β = 15.614, p < 0,001), maximal aerobic capacity (β = 0.399, p = 0.005) and LVEF (β = 0.698, p = 0.007) at 12 months.

Conclusions

Higher O3I was associated with a more favorable cardiometabolic risk profile and predictive of higher submaximal/maximal aerobic capacity and lower BMI/truncal adiposity in HFpEF patients.

Graphic abstract

Omega-3 fatty acid blood levels are inversely associated with cardiometabolic risk factors in HFpEF patients. Higher O3I was associated with a more favorable cardiometabolic risk profile and aerobic capacity (left) but did not correlate with echocardiographic markers for left ventricular diastolic function or neurohumoral activation (right). An O3I-driven intervention trial might be warranted to answer the question whether O3-FA in therapeutic doses (with the target O3I 8–11%) impact on echocardiographic markers for left ventricular diastolic function and neurohumoral activation in patients with HFpEF. This figure contains modified images from Servier Medical Art (https://smart.servier.com) licensed by a Creative Commons Attribution 3.0 Unported License.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00392-021-01925-9.

The Evolving Role of Omega 3 Fatty Acids in Cardiovascular Disease: Is Icosapent Ethyl the Answer?

Atherosclerotic cardiovascular disease (ASCVD) remains the leading cause of morbidity and mortality globally. Despite significant advances in pharmacotherapies and the beneficial effects of statin therapy on ASCVD outcomes and progression of atherosclerosis, residual cardiovascular (CV) risk remains. Extensive evidence has identified the contribution of atherogenic dyslipidaemia, which is particularly characterised by elevated triglycerides (TGL) as a key driver of CV risk, even if low-density lipoprotein cholesterol levels are well controlled. Epidemiologic and genetic/Mendelian randomisation studies have demonstrated that elevated TGL levels serve as an independent marker for an increased risk of ischaemic events, highlighting TGLs as a suitable therapeutic target. Clinical studies have shown that omega 3 fatty acids (OM3FA) are effective in lowering TGLs; however, to date, trials and meta-analyses of combined OM3FA products have not demonstrated any clinical CV outcome benefit in patients receiving statins. However, icosapent ethyl (IPE) - a highly purified, stable ethyl ester of eicosapentaenoic acid (EPA) - has been rigorously demonstrated in multiple studies to be a useful adjunctive therapy to address residual CV risk. EPA is an omega-3 polyunsaturated fatty acid that is incorporated into membrane phospholipid bilayers and is reported to exert multiple beneficial effects along the pathway of coronary atherosclerosis. In this brief review, we will provide an overview of the mode of action of IPE in coronary atherosclerosis, the robust clinical evidence and trial data supporting its use, and expert consensus/recommendations on its use in specific populations, as an adjunct to existing anti-atherosclerotic therapies.

Changes in lipoprotein particle subclasses, standard lipids, and apolipoproteins after supplementation with n-3 or n-6 PUFAs in abdominal obesity: A randomized double-blind crossover study

BACKGROUND & AIMS

Marine-derived omega-3 (n-3) polyunsaturated fatty acids (PUFAs), mainly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), lower circulating levels of triacylglycerols (TAGs), and the plant-derived omega-6 (n-6) PUFA linoleic acid (LA) may reduce cholesterol levels. Clinical studies on effects of these dietary or supplemental PUFAs on other blood fat fractions are few and have shown conflicting results. This study aimed to determine effects of high-dose supplemental n-3 (EPA + DHA) and n-6 (LA) PUFAs from high-quality oils on circulating lipoprotein subfractions and standard lipids (primary outcomes), as well as apolipoproteins, fatty acids, and glycemic control (secondary outcomes), in females and males with abdominal obesity.

METHODS

This was a randomized double-blind crossover study with two 7-wk intervention periods separated by a 9-wk washout phase. Females (n = 16) were supplemented with 3 g/d of EPA + DHA (TAG fish oil) or 15 g/d of LA (safflower oil), while males (n = 23) received a dose of 4 g/d of EPA + DHA or 20 g/d of LA. In fasting blood samples, we investigated lipoprotein particle subclasses by nuclear magnetic resonance spectroscopy, as well as standard lipids, apolipoproteins, fatty acid profiles, and glucose and insulin. Data were analyzed by linear mixed-effects modeling with 'subjects' as the random factor.

RESULTS

The difference between interventions in relative change scores was among the lipoprotein subfractions significant for total very-low-density lipoproteins (VLDLs) (n-3 vs. n-6: -38%∗ vs. +16%, p < 0.001; ∗: significant within-treatment change score), large VLDLs (-58%∗ vs. -0.91%, p < 0.001), small VLDLs (-57%∗ vs. +41%∗, p < 0.001), total low-density lipoproteins (LDLs) (+5.8%∗ vs. -4.3%∗, p = 0.002), large LDLs (+23%∗ vs. -2.1%, p = 0.004), total high-density lipoproteins (HDLs) (-6.0%∗ vs. +3.7%, p < 0.001), large HDLs (+11%∗ vs. -5.3%, p = 0.001), medium HDLs (-24%∗ vs. +6.2%, p = 0.030), and small HDLs (-9.9%∗ vs. +9.6%∗, p = 0.002), and among standard lipids for TAGs (-16%∗ vs. -2.6%, p = 0.014), non-esterified fatty acids (-19%∗ vs. +5.5%, p = 0.033), and total cholesterol (-0.28% vs. -4.4%∗, p = 0.042). A differential response in relative change scores was also found for apolipoprotein (apo)B (+0.40% vs. -6.0%∗, p = 0.008), apoA-II (-6.0%∗ vs. +1.5%, p = 0.001), apoC-II (-11%∗ vs. -1.7%, p = 0.025), and apoE (+3.3% vs. -3.8%, p = 0.028).

CONCLUSIONS

High-dose supplementation of high-quality oils with n-3 (EPA + DHA) or n-6 (LA) PUFAs was followed by reductions in primarily TAG- or cholesterol-related markers, respectively. The responses after both interventions point to changes in the lipoprotein-lipid-apolipoprotein profile that have been associated with reduced cardiometabolic risk, also among people with TAG or LDL-C levels within the normal range.

REGISTRATION

Registered under ClinicalTrials.gov Identifier: NCT02647333.

CLINICAL TRIAL REGISTRATION

Registered at https://clinicaltrials.gov/ct2/show/NCT02647333.

Micronutrients, Phytochemicals and Mediterranean Diet: A Potential Protective Role against COVID-19 through Modulation of PAF Actions and Metabolism

The new coronavirus disease 2019 (COVID-19) pandemic is an emerging situation with high rates of morbidity and mortality, in the pathophysiology of which inflammation and thrombosis are implicated. The disease is directly connected to the nutritional status of patients and a well-balanced diet is recommended by official sources. Recently, the role of platelet activating factor (PAF) was suggested in the pathogenesis of COVID-19. In the present review several micronutrients (vitamin A, vitamin C, vitamin E, vitamin D, selenium, omega-3 fatty acids, and minerals), phytochemicals and Mediterranean diet compounds with potential anti-COVID activity are presented. We further underline that the well-known anti-inflammatory and anti-thrombotic actions of the investigated nutrients and/or holistic dietary schemes, such as the Mediterranean diet, are also mediated through PAF. In conclusion, there is no single food to prevent coronavirus Although the relationship between PAF and COVID-19 is not robust, a healthy diet containing PAF inhibitors may target both inflammation and thrombosis and prevent the deleterious effects of COVID-19. The next step is the experimental confirmation or not of the PAF-COVID-19 hypothesis.

Bioactive Compounds for the Management of Hypertriglyceridemia: Evidence From Clinical Trials and Putative Action Targets

Hypertriglyceridemia refers to the presence of elevated concentrations of triglycerides (TG) in the bloodstream (TG >200 mg/dL). This lipid alteration is known to be associated with an increased risk of atherosclerosis, contributing overall to the onset of atherosclerotic cardiovascular disease (CVD). Guidelines for the management of hypertriglyceridemia are based on both lifestyle intervention and pharmacological treatment, but poor adherence, medication-related costs and side effects can limit the success of these interventions. For this reason, the search for natural alternative approaches to reduce plasma TG levels currently represents a hot research field. This review article summarizes the most relevant clinical trials reporting the TG-reducing effect of different food-derived bioactive compounds. Furthermore, based on the evidence obtained from in vitro studies, we provide a description and classification of putative targets of action through which several bioactive compounds can exert a TG-lowering effect. Future research may lead to investigations of the efficacy of novel nutraceutical formulations consisting in a combination of bioactive compounds which contribute to the management of plasma TG levels through different action targets.

The Road to Approval: a Perspective on the Role of Icosapent Ethyl in Cardiovascular Risk Reduction

PURPOSE OF REVIEW

Epidemiological studies have long suggested the cardiovascular benefits of omega-3 fatty acids (OM3FAs). However, until recently, clinical trials using OM3FAs have been largely negative with respect to their cardioprotective effects. In this review, we aim to summarize key clinical trials, examine the clinical benefits of eicosapentaenoic acid (EPA) and potential mechanisms, and review the changes in guidelines and recommendations.

RECENT FINDINGS

The Reduction of Cardiovascular Events with Icosapent Ethyl-Intervention Trial (REDUCE-IT) has demonstrated significant cardiovascular mortality benefits of purified EPA ethyl ester, with a 25% relative risk reduction in major cardiovascular events. As first of its class to be approved, icosapent ethyl offers a new option to further reduce cardiovascular risks in patients already treated with maximally tolerated statins.

Mechanistic insights into cardiovascular protection for omega-3 fatty acids and their bioactive lipid metabolites

Patients with well-controlled low-density lipoprotein cholesterol levels, but persistent high triglycerides, remain at increased risk for cardiovascular events as evidenced by multiple genetic and epidemiologic studies, as well as recent clinical outcome trials. While many trials of low-dose ω3-polyunsaturated fatty acids (ω3-PUFAs), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) have shown mixed results to reduce cardiovascular events, recent trials with high-dose ω3-PUFAs have reignited interest in ω3-PUFAs, particularly EPA, in cardiovascular disease (CVD). REDUCE-IT demonstrated that high-dose EPA (4 g/day icosapent-ethyl) reduced a composite of clinical events by 25% in statin-treated patients with established CVD or diabetes and other cardiovascular risk factors. Outcome trials in similar statin-treated patients using DHA-containing high-dose ω3 formulations have not yet shown the benefits of EPA alone. However, there are data to show that high-dose ω3-PUFAs in patients with acute myocardial infarction had reduced left ventricular remodelling, non-infarct myocardial fibrosis, and systemic inflammation. ω3-polyunsaturated fatty acids, along with their metabolites, such as oxylipins and other lipid mediators, have complex effects on the cardiovascular system. Together they target free fatty acid receptors and peroxisome proliferator-activated receptors in various tissues to modulate inflammation and lipid metabolism. Here, we review these multifactorial mechanisms of ω3-PUFAs in view of recent clinical findings. These findings indicate physico-chemical and biological diversity among ω3-PUFAs that influence tissue distributions as well as disparate effects on membrane organization, rates of lipid oxidation, as well as various receptor-mediated signal transduction pathways and effects on gene expression.

Omega-3 fatty acid exposure with a low-fat diet in patients with past hypertriglyceridemia-induced acute pancreatitis; an exploratory, randomized, open-label crossover study

BACKGROUND

Omega-3 fatty acids (OM3-FAs) are recommended with a low-fat diet for severe hypertriglyceridemia (SHTG), to reduce triglycerides and acute pancreatitis (AP) risk. A low-fat diet may reduce pancreatic lipase secretion, which is required to absorb OM3-ethyl esters (OM3-EEs), but not OM3-carboxylic acids (OM3-CAs).

METHODS

In this exploratory, randomized, open-label, crossover study, 15 patients with SHTG and previous AP were instructed to take OM3-CA (2 g or 4 g) and OM3-EE 4 g once daily for 4 weeks, while adhering to a low-fat diet. On day 28 of each treatment phase, a single dose was administered in the clinic with a liquid low-fat meal, to assess 24-h plasma exposure. Geometric least-squares mean ratios were used for between-treatment comparisons of baseline (day 0)-adjusted area under the plasma concentration versus time curves (AUC_0-24) and maximum plasma concentrations (C_max) for eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA).

RESULTS

Before initiating OM3-FA treatment, mean baseline fasting plasma EPA + DHA concentrations (nmol/mL) were 723 for OM3-CA 2 g, 465 for OM3-CA 4 g and 522 for OM3-EE 4 g. At week 4, mean pre-dose fasting plasma EPA + DHA concentrations increased by similar amounts (+ 735 - + 768 nmol/mL) for each treatment. During the 24-h exposure assessment (day 28), mean plasma EPA + DHA increased from pre-dose to the maximum achieved concentration by + 32.7%, + 45.8% and + 3.1% with single doses of OM3-CA 2 g, OM3-CA 4 g and OM3-EE 4 g, respectively. Baseline-adjusted AUC_0-24 was 60% higher for OM3-CA 4 g than for OM3-EE 4 g and baseline-adjusted C_max was 94% higher (both non-significant).

CONCLUSIONS

Greater 24-h exposure of OM3-CA versus OM3-EE was observed for some parameters when administered with a low-fat meal at the clinic on day 28. However, increases in pre-dose fasting plasma EPA + DHA over the preceding 4-week dosing period were similar between treatments, leading overall to non-significant differences in baseline (day 0)-adjusted AUC_0-24 and C_max EPA + DHA values. It is not clear why the greater 24-h exposure of OM3-CA versus OM3-EE observed with a low-fat meal did not translate into significantly higher pre-dose fasting levels of DHA + EPA with longer-term use.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT02189252, Registered 23 June 2014.

Emerging Mechanisms of Cardiovascular Protection for the Omega-3 Fatty Acid Eicosapentaenoic Acid

Patients with well-controlled LDL (low-density lipoprotein) levels still have residual cardiovascular risk associated with elevated triglycerides. Epidemiological studies have shown that elevated fasting triglyceride levels associate independently with incident cardiovascular events, and abundant recent human genetic data support the causality of TGRLs (triglyceride-rich lipoproteins) in atherothrombosis. Omega-3 fatty acids, such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), lower blood triglyceride concentrations but likely exert additional atheroprotective properties at higher doses. Omega-3 fatty acids modulate T-cell differentiation and give rise to various prostaglandins and specialized proresolving lipid mediators that promote resolution of tissue injury and inflammation. The REDUCE-IT (Reduction of Cardiovascular Events with Icosapent Ethyl-Intervention Trial) with an EPA-only formulation lowered a composite of cardiovascular events by 25% in patients with established cardiovascular disease or diabetes mellitus and other cardiovascular risk factors. This clinical benefit likely arises from multiple molecular mechanisms discussed in this review. Indeed, human plaques readily incorporate EPA, which may render them less likely to trigger clinical events. EPA and DHA differ in their effects on membrane structure, rates of lipid oxidation, inflammatory biomarkers, and endothelial function as well as tissue distributions. Trials that have evaluated DHA-containing high-dose omega-3 fatty acids have thus far not shown the benefits of EPA alone demonstrated in REDUCE-IT. This review will consider the mechanistic evidence that helps to understand the potential mechanisms of benefit of EPA.

Experimental Therapeutics for Challenging Clinical Care of a Patient with an Extremely Rare Homozygous APOC2 Mutation

Background

Among many causes of hypertriglyceridemia (HTG), familial chylomicronemia syndrome (FCS) is a rare monogenic disorder that manifests as severe HTG and acute pancreatitis. Among the known causal genes for FCS, mutations in APOC2 only account for <2% of cases. Medical nutrition therapy is critical for FCS because usual triglyceride- (TG-) lowering medications are ineffective. Therapeutic plasma exchange (TPE) with fresh frozen plasma (FFP) is an option to urgently reduce TG and pancreatitis episodes. Several novel biologics are under development to treat HTG and may provide therapeutic options for FCS in the future.

Objective

We present the challenging care of a 43-year-old man with FCS with apoC-II deficiency and the results of two types of TPE and of investigational TG-lowering biologic therapies.

Results

The patient's lipid profile was consistent with FCS. A novel homozygous variant was identified in APOC2, and its pathogenicity was confirmed. Even on a fat-restricted diet, his care was tremendously complicated with unremitting bouts of pancreatitis. TPE with FFP replacement lowered TG >90% post-sessions and appeared to reduce pancreatitis episodes. Experimental ANGPTL3 and APOC3 inhibitors each lowered TG by >50%.

Conclusions

Our case demonstrates the importance of delineating and defining the underlying etiology of a rare disorder to optimize therapy and to minimize unfavorable outcomes.

Lifestyle factors and high-risk atherosclerosis: Pathways and mechanisms beyond traditional risk factors

Despite major efforts to reduce atherosclerotic cardiovascular disease (ASCVD) burden with conventional risk factor control, significant residual risk remains. Recent evidence on non-traditional determinants of cardiometabolic health has advanced our understanding of lifestyle-disease interactions. Chronic exposure to environmental stressors like poor diet quality, sedentarism, ambient air pollution and noise, sleep deprivation and psychosocial stress affect numerous traditional and non-traditional intermediary pathways related to ASCVD. These include body composition, cardiorespiratory fitness, muscle strength and functionality and the intestinal microbiome, which are increasingly recognized as major determinants of cardiovascular health. Evidence points to partially overlapping mechanisms, including effects on inflammatory and nutrient sensing pathways, endocrine signalling, autonomic function and autophagy. Of particular relevance is the potential of low-risk lifestyle factors to impact on plaque vulnerability through altered adipose tissue and skeletal muscle phenotype and secretome. Collectively, low-risk lifestyle factors cause a set of phenotypic adaptations shifting tissue cross-talk from a proinflammatory milieu conducive for high-risk atherosclerosis to an anti-atherogenic milieu. The ketone body ß-hydroxybutyrate, through inhibition of the NLRP-3 inflammasome, is likely to be an intermediary for many of these observed benefits. Adhering to low-risk lifestyle factors adds to the prognostic value of optimal risk factor management, and benefit occurs even when the impact on conventional risk markers is discouragingly minimal or not present. The aims of this review are (a) to discuss novel lifestyle risk factors and their underlying biochemical principles and (b) to provide new perspectives on potentially more feasible recommendations to improve long-term adherence to low-risk lifestyle factors.

Efficacy and Safety of Omega-3 Fatty Acids in Patients Treated with Statins for Residual Hypertriglyceridemia: A Randomized, Double-Blind, Placebo-Controlled Clinical Trial

BACKGROUND

Cardiovascular risk remains increased despite optimal low density lipoprotein cholesterol (LDL-C) level induced by intensive statin therapy. Therefore, recent guidelines recommend non-high density lipoprotein cholesterol (non-HDL-C) as a secondary target for preventing cardiovascular events. The aim of this study was to assess the efficacy and tolerability of omega-3 fatty acids (OM3-FAs) in combination with atorvastatin compared to atorvastatin alone in patients with mixed dyslipidemia.

METHODS

This randomized, double-blind, placebo-controlled, parallel-group, and phase III multicenter study included adults with fasting triglyceride (TG) levels ≥200 and <500 mg/dL and LDL-C levels <110 mg/dL. Eligible subjects were randomized to ATOMEGA (OM3-FAs 4,000 mg plus atorvastatin calcium 20 mg) or atorvastatin 20 mg plus placebo groups. The primary efficacy endpoints were the percent changes in TG and non-HDL-C levels from baseline at the end of treatment.

RESULTS

After 8 weeks of treatment, the percent changes from baseline in TG (-29.8% vs. 3.6%, P<0.001) and non-HDL-C (-10.1% vs. 4.9%, P<0.001) levels were significantly greater in the ATOMEGA group (n=97) than in the atorvastatin group (n=103). Moreover, the proportion of total subjects reaching TG target of <200 mg/dL in the ATOMEGA group was significantly higher than that in the atorvastatin group (62.9% vs. 22.3%, P<0.001). The incidence of adverse events did not differ between the two groups.

CONCLUSION

The addition of OM3-FAs to atorvastatin improved TG and non-HDL-C levels to a significant extent compared to atorvastatin alone in subjects with residual hypertriglyceridemia.

The Roles of ApoC-III on the Metabolism of Triglyceride-Rich Lipoproteins in Humans

Cardiovascular disease (CVD) is the leading cause of death globally. It is well-established based on evidence accrued during the last three decades that high plasma concentrations of cholesterol-rich atherogenic lipoproteins are causatively linked to CVD, and that lowering these reduces atherosclerotic cardiovascular events in humans (1-9). Historically, most attention has been on low-density lipoproteins (LDL) since these are the most abundant atherogenic lipoproteins in the circulation, and thus the main carrier of cholesterol into the artery wall. However, with the rise of obesity and insulin resistance in many populations, there is increasing interest in the role of triglyceride-rich lipoproteins (TRLs) and their metabolic remnants, with accumulating evidence showing they too are causatively linked to CVD. Plasma triglyceride, measured either in the fasting or non-fasting state, is a useful index of the abundance of TRLs and recent research into the biology and genetics of triglyceride heritability has provided new insight into the causal relationship of TRLs with CVD. Of the genetic factors known to influence plasma triglyceride levels variation in APOC3- the gene for apolipoprotein (apo) C-III - has emerged as being particularly important as a regulator of triglyceride transport and a novel therapeutic target to reduce dyslipidaemia and CVD risk (10).

Investigational drugs in development for hypertriglyceridemia: a coming-of-age story

Introduction: Elevated triglyceride (TG) level is a prevalent condition in the general population and in patients with cardiovascular (CV) risk even under statin therapy. Severe hypertriglyceridemia (HTG) puts patients at risk for acute pancreatitis. Several TG-lowering drugs failed in clinical trials, but subgroup analyses suggest that high-risk patients, such as those with atherogenic dyslipidemia or diabetes, benefit from TG lowering.Areas covered: We review advances for TG-lowering drugs in clinical development. These include selective PPARα modulators, omega-3 fatty acid formulations that have been approved for severe HTG, and inhibitors of apolipoprotein C-III, angiopoietin-like-3 or microsomal transfer protein. Lessons learned from the success of the phase 3 trial REDUCE-IT with high-dose icosapent ethyl are also reviewed.Expert opinion: We believe that TG-lowering therapies are coming of age as they will allow to treat patients with high CV risk and moderate HTG, including T2D subjects, as well as patients with severe HTG or even homozygous familial hypercholesterolemia, all of which being 'optimally' treated with a statin. More studies on the impact of therapy on quality of life in patients with severe HTG should be conducted with the help of patient registries.

Effects of Icosapent Ethyl (Eicosapentaenoic Acid Ethyl Ester) on Atherogenic Lipid/Lipoprotein, Apolipoprotein, and Inflammatory Parameters in Patients With Elevated High-Sensitivity C-Reactive Protein (from the ANCHOR Study)

Icosapent ethyl is pure prescription eicosapentaenoic acid approved at 4 g/day as an adjunct to diet to reduce triglycerides (TG) in adults with TG ≥500 mg/dl. Elevated high-sensitivity C-reactive protein (hsCRP) is associated with increased cardiovascular risk. The 12-week ANCHOR study randomized 702 statin-treated patients at increased cardiovascular risk with TG 200 to 499 mg/dl despite low-density lipoprotein cholesterol (LDL-C) control (40 to 99 mg/dl). This post hoc analysis assessed 246 ANCHOR patients with baseline hsCRP ≥ 2.0 mg/L randomized to icosapent ethyl 4 g/day (n = 126; approved dose) or placebo (n = 120). Without increasing LDL-C, icosapent ethyl significantly reduced median TG (-20%; p < 0.0001), non-high-density lipoprotein cholesterol (-12.3%; p < 0.0001), total cholesterol (-11.1%; p < 0.0001), high-density lipoprotein cholesterol (-5.2%; p = 0.0042), very LDL-C (-21.0%; p < 0.0001), very low-density lipoprotein TG (-22.9%; p < 0.0001), remnant lipoprotein cholesterol (-23.0%; p = 0.0125), apolipoprotein B (-7.4%; p = 0.0021), apolipoprotein C-III (-16%; p < 0.0001), oxidized LDL (-13.7%; p = 0.0020), lipoprotein-associated phospholipase A₂ (-19.6%; p < 0.0001), and hsCRP (-17.9%; p = 0.0213) versus placebo, while interleukin-6 and intercellular adhesion molecule-1 were not significantly changed. Eicosapentaenoic acid increased with icosapent ethyl 4 g/day +637% in plasma and +632% in red blood cells versus placebo (both p < 0.0001). Icosapent ethyl exhibited a safety profile similar to placebo. In conclusion, in statin-treated patients with hsCRP ≥ 2.0 mg/L and TG 200 to 499 mg/dl at baseline, icosapent ethyl 4 g/day significantly and safely reduced TG and other atherogenic and inflammatory parameters without increasing LDL-C versus placebo.

Omega-3 Fatty Acids for the Management of Hypertriglyceridemia: A Science Advisory From the American Heart Association

Hypertriglyceridemia (triglycerides 200-499 mg/dL) is relatively common in the United States, whereas more severe triglyceride elevations (very high triglycerides, ≥500 mg/dL) are far less frequently observed. Both are becoming increasingly prevalent in the United States and elsewhere, likely driven in large part by growing rates of obesity and diabetes mellitus. In a 2002 American Heart Association scientific statement, the omega-3 fatty acids (n-3 FAs) eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) were recommended (at a dose of 2-4 g/d) for reducing triglycerides in patients with elevated triglycerides. Since 2002, prescription agents containing EPA+DHA or EPA alone have been approved by the US Food and Drug Administration for treating very high triglycerides; these agents are also widely used for hypertriglyceridemia. The purpose of this advisory is to summarize the lipid and lipoprotein effects resulting from pharmacological doses of n-3 FAs (>3 g/d total EPA+DHA) on the basis of new scientific data and availability of n-3 FA agents. In treatment of very high triglycerides with 4 g/d, EPA+DHA agents reduce triglycerides by ≥30% with concurrent increases in low-density lipoprotein cholesterol, whereas EPA-only did not raise low-density lipoprotein cholesterol in very high triglycerides. When used to treat hypertriglyceridemia, n-3 FAs with EPA+DHA or with EPA-only appear roughly comparable for triglyceride lowering and do not increase low-density lipoprotein cholesterol when used as monotherapy or in combination with a statin. In the largest trials of 4 g/d prescription n-3 FA, non-high-density lipoprotein cholesterol and apolipoprotein B were modestly decreased, indicating reductions in total atherogenic lipoproteins. The use of n-3 FA (4 g/d) for improving atherosclerotic cardiovascular disease risk in patients with hypertriglyceridemia is supported by a 25% reduction in major adverse cardiovascular events in REDUCE-IT (Reduction of Cardiovascular Events With EPA Intervention Trial), a randomized placebo-controlled trial of EPA-only in high-risk patients treated with a statin. The results of a trial of 4 g/d prescription EPA+DHA in hypertriglyceridemia are anticipated in 2020. We conclude that prescription n-3 FAs (EPA+DHA or EPA-only) at a dose of 4 g/d (>3 g/d total EPA+DHA) are an effective and safe option for reducing triglycerides as monotherapy or as an adjunct to other lipid-lowering agents.

Emerging Evidence that ApoC-III Inhibitors Provide Novel Options to Reduce the Residual CVD

Purpose of Review

Apolipoprotein C-III (apoC-III) is known to inhibit lipoprotein lipase (LPL) and function as an important regulator of triglyceride metabolism. In addition, apoC-III has also more recently been identified as an important risk factor for cardiovascular disease. This review summarizes the mechanisms by which apoC-III induces hypertriglyceridemia and promotes atherogenesis, as well as the findings from recent clinical trials using novel strategies for lowering apoC-III.

Recent Findings

Genetic studies have identified subjects with heterozygote loss-of-function (LOF) mutations in APOC3, the gene coding for apoC-III. Clinical characterization of these individuals shows that the LOF variants associate with a low-risk lipoprotein profile, in particular reduced plasma triglycerides. Recent results also show that complete deficiency of apoC-III is not a lethal mutation and is associated with very rapid lipolysis of plasma triglyceride-rich lipoproteins (TRL). Ongoing trials based on emerging gene-silencing technologies show that intervention markedly lowers apoC-III levels and, consequently, plasma triglyceride. Unexpectedly, the evidence points to apoC-III not only inhibiting LPL activity but also suppressing removal of TRLs by LPL-independent pathways.

Summary

Available data clearly show that apoC-III is an important cardiovascular risk factor and that lifelong deficiency of apoC-III is cardioprotective. Novel therapies have been developed, and results from recent clinical trials indicate that effective reduction of plasma triglycerides by inhibition of apoC-III might be a promising strategy in management of severe hypertriglyceridemia and, more generally, a novel approach to CHD prevention in those with elevated plasma triglyceride.

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.

Network Meta-Analysis of Metabolic Effects of Olive-Oil in Humans Shows the Importance of Olive Oil Consumption With Moderate Polyphenol Levels as Part of the Mediterranean Diet

The beneficial role of olive oil consumption is nowadays widely recognized. However, it is not clear whether its health effects are due to the presence of monounsaturated lipids and/or to the antioxidant fraction of microconstituents present in olive oil. The aim of the present study was to analyze the exact role of olive oil in the modification of metabolic factors (glucose and circulating lipids) and explore the role of its antioxidant polyphenols. In the present work, we have performed a network meta-analysis of 30 human intervention studies, considering direct and indirect interactions and impact of each constituent. Interestingly, we show that the impact of olive oil on glucose, triglycerides, and LDL-cholesterol is mediated through an adherence to the Mediterranean diet, with the only notable effect of olive oil polyphenols being the increase of HDL-cholesterol, and the amelioration of the antioxidant and inflammatory status of the subjects. Additionally, we report for the first time that lower antioxidant polyphenol levels may be sufficient for the beneficial effects of olive oil, while we show that the lipid fraction of olive oil may be responsible for some of its beneficial actions. In all parameters examined the beneficial effect of olive oil was more pronounced in subjects with an established metabolic syndrome or other chronic conditions/diseases. In conclusion, all these findings provide new knowledge that could lead to re-establishment of the role of olive oil in human nutrition.

A 7-day high-PUFA diet reduces angiopoietin-like protein 3 and 8 responses and postprandial triglyceride levels in healthy females but not males: a randomized control trial

BACKGROUND

Polyunsaturated fatty acids (PUFAs) have beneficial effects on hypertriglyceridemia although their effect on angiopoietin-like proteins (ANGPTLs), specifically ANGPTL3, ANGPTL4 and ANGPTL8 is unknown.

OBJECTIVE

To determine whether a high-PUFA diet improves postprandial triglyceride (TG) levels through reducing ANGPTL responses following high saturated fat (SFA) meals.

METHODS

Twenty-six adults were randomized into a PUFA diet (n = 16) or a control diet group (n = 10). Participants completed a pre-diet visit (v1) where they were given two SFA-rich, high-fat meals. Blood draws were taken at fasting and every 2 h postprandially for a total of 8 h. After v1, participants completed a 7d diet of the same macronutrient proportions (50% carbohydrate, 35% fat, 15% protein) but with different fatty acid (FA) compositions (PUFA = 21% of total energy from PUFAs vs. Control = 7% of total energy from PUFA). All participants then completed the post-diet visit (v2) identical to v1.

RESULTS

In the PUFA group, females, but not males, reduced TG concentrations (Area under the curve (AUC): 141.2 ± 18.7 vs. 80.7 ± 6.5 mg/dL/h, p = 0.01, for v1 vs. v2, respectively). Fasting and postprandial AUC levels of ANGPTL3 and 8, but not ANGPTL4, also decreased from v1 to v2 in PUFA females, but not males. No changes from v1 to v2 were seen in either sex in the control group.

CONCLUSIONS

A PUFA-rich diet improves TG levels in response to high-SFA meals with reductions in ANGPTL3 and ANGPTL8. PUFAs may be more protective against hypertriglyceridemia in females, compared to males since no diet effect was observed in males.

TRIAL REGISTRATION

NCT02246933.

Effects of a Self-micro-emulsifying Delivery System Formulation Versus a Standard ω-3 Acid Ethyl Ester Product on the Bioavailability of Eicosapentaenoic Acid and Docosahexaenoic Acid: A Study in Healthy Men and Women in a Fasted State

PURPOSE

Intakes of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are associated with several potential health benefits, but standard ethyl ester (EE) formulations of these ω-3 fatty acids require the co-ingestion of fat for adequate absorption. The objective of this research was to assess the relative bioavailability of EPA and DHA administered in a proprietary self-micro-emulsifying delivery system (SMEDS) formulation compared with EPA and DHA in a standard ω-3 acid EE product in healthy men and women in a fasted state.

METHODS

This randomized crossover study investigated the bioavailability of 2 encapsulated formulations of EPA and DHA, a capsule containing 500 mg EPA + DHA administered in a SMEDS formulation (SMEDS treatment), and a capsule containing 840 mg EPA + DHA in a standard ω-3 acid EE formulation (EE treatment). Subjects consumed a single dose of their assigned capsule in a fasting state, and plasma was collected before and for 24 h after dosing. Subjects underwent a ≥14-day washout and were crossed over to the other treatment condition. Plasma concentrations of EPA, DHA, and EPA + DHA were assessed.

FINDINGS

Twenty-three subjects (11 women, 12 men; mean [SEM] age, 33.8 [2.1] years; and body mass index, 24.9 [0.7] kg/m²) completed the trial. The baseline-adjusted, dose-normalized, arithmetic means (SD) of the incremental (i)-AUC_0-24h for EPA + DHA were 543 (266) and 102 (88.2) h · μg/mL/g for the SMEDS and EE formulations, respectively (P < 0.001). The iAUC_0-24h least-squares geometric mean ratio (90% CI) for SMEDS:standard EE was 475/58 = 8.2 (4.8-13.9), indicating markedly higher bioavailability of EPA + DHA with the SMEDS formulation compared to the standard EE formulation. This finding was also true for EPA (geometric mean ratio [90% CI], 18.2 [11.3-29.3]) and DHA (geometric mean ratio [90% CI], 4.5 [2.9-7.0]).

IMPLICATIONS

The SMEDS delivery system markedly enhanced appearance in plasma of EPA and DHA, compared to a standard EE formulation, when ingested in the fasting state. ClinicalTrials.gov identifier: NCT03443076.

Effect of omega-3 supplements on plasma apolipoprotein C-III concentrations: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Apolipoprotein C-III (apo C-III) is a key regulator of triglycerides metabolism. The aim of this meta-analysis was to assess the effect of fish omega-3 polyunsaturated fatty acids (PUFAs) on apo C-III levels.

METHODS

Randomized placebo-controlled trials investigating the impact of omega-3 on apo C-III levels were searched in PubMed-Medline, SCOPUS, Web of Science and Google Scholar. A random-effects model and generic inverse variance method were used for quantitative data synthesis. Sensitivity analysis was conducted using the leave-one-out method. A weighted random-effects meta-regression was performed to evaluate the impact of potential confounders on glycemic parameters.

RESULTS

This meta-analysis comprising 2062 subjects showed a significant reduction of apo C-III concentrations following treatment with omega-3 (WMD: -22.18 mg/L, 95% confidence interval: -31.61, -12.75, p < .001; I²: 88.24%). Subgroup analysis showed a significant reduction of plasma apo C-III concentrations by eicosapentaenoic acid (EPA) ethyl esters but not omega-3 carboxylic acids or omega-3 ethyl esters. There was a greater apo C-III reduction with only EPA as compared with supplements containing EPA and docosahexaenoic acid (DHA) or only DHA. A positive association between the apo C-III-lowering effect of omega-3 with baseline apo C-III concentrations and treatment duration was found.

CONCLUSIONS

This meta-analysis has shown that omega-3 PUFAs might significantly decrease apo C-III. Key messages Omega-3 PUFA supplements significantly reduce apo C-III plasma levels, particularly in hypertriglyceridemic patients when applied in appropriate dose (more than 2 g/day) Triglyceride (TG)-lowering effect is achieved via peroxisome proliferator-activated receptors α Further studies should address the effect of omega-3 PUFAs alone or with other lipid-lowering drugs in order to provide a final answer whether apo C-III could be an important target for prevention of cardiovascular disease New apo C-III antisense oligonucleotide drug (Volanesorsen) showed to be promising in decreasing elevated TGs by reducing levels of apo C-III mRNA.

Science behind the cardio-metabolic benefits of omega-3 polyunsaturated fatty acids: biochemical effects vs. clinical outcomes

Lower incidence of cardiovascular disease (CVD) in the Greenland Inuit, Northern Canada and Japan has been attributed to their consumption of seafood rich in long chain omega-3 polyunsaturated fatty acids (LCn-3PUFA). While a large majority of pre-clinical and intervention trials have demonstrated heart health benefits of LCn-3PUFA, some studies have shown no effects or even negative effects. LCn-3PUFA have been shown to favourably modulate blood lipid levels, particularly a reduction in circulating levels of triglycerides. High density lipoprotein-cholesterol (HDL-C) levels are elevated following dietary supplementation with LCn-3PUFA. Although LCn-3PUFA have been shown to increase low-density lipoprotein-cholesterol (LDL-C) levels, the increase is primarily in the large-buoyant particles that are less atherogenic than small-dense LDL particles. The anti-inflammatory effects of LCn-3PUFA have been clearly outlined with inhibition of NFkB mediated cytokine production being the main mechanism. In addition, reduction in adhesion molecules (intercellular adhesion molecule, ICAM and vascular cell adhesion molecule 1, VCAM-1) and leukotriene production have also been demonstrated following LCn-3PUFA supplementation. Anti-aggregatory effects of LCn-3PUFA have been a subject of controversy, however, recent studies showing sex-specific effects on platelet aggregation have helped resolve the effects on hyperactive platelets. Improvements in endothelium function, blood flow and blood pressure after LCn-3PUFA supplementation add to the mechanistic explanation on their cardio-protective effects. Modulation of adipose tissue secretions including pro-inflammatory mediators and adipokines by LCn-3PUFA has re-ignited interest in their cardiovascular health benefits. The aim of this narrative review is to filter out the reasons for possible disparity between cohort, mechanistic, pre-clinical and clinical studies. The focus of the article is to provide possible explanation for the observed controversies surrounding heart health benefits of LCn-3PUFA.

N-3 polyunsaturated fatty acids improve lipoprotein particle size and concentration in Japanese patients with type 2 diabetes and hypertriglyceridemia: a pilot study

Background

Patients with type 2 diabetes are at high risk for cardiovascular disease. Although hydroxymethylglutaryl-CoA reductase inhibitors (statins) can reduce cardiovascular events, residual risk remains even after target low-density lipoprotein cholesterol (LDL-C) levels have been achieved. Lipoprotein particle size and fraction changes are thought to contribute to such risks. The purpose of this study was to evaluate the effects of n-3 polyunsaturated fatty acids (n-3 PUFAs), predominantly eicosapentaenoic acid and docosahexaenoic acid, on lipoprotein particle size, concentration, and glycemic control in Japanese patients with type 2 diabetes and hypertriglyceridemia.

Methods

This was a multicenter, prospective, open-label, single arm study. We enrolled 14 patients with type 2 diabetes and hypertriglyceridemia treated with statins and dipeptidyl peptidase-4 inhibitors with glycated hemoglobin (HbA1c) < 8.0%, LDL-C < 120 mg/dL, and fasting triglyceride ≥150 mg/dL. After a 12-week observation period, they were treated with 4 g/day n-3 PUFAs for 12 weeks. Lipoprotein particle sizes, concentrations, lipoprotein insulin resistance (LPIR) scores, lipid profiles, HbA1c, and fasting plasma glucose (FPG) were measured before and after treatment. Lipoprotein profiles were measured by nuclear magnetic resonance spectroscopy. Data were analyzed using Wilcoxon signed-rank tests.

Results

Concentrations of total cholesterol (P < 0.001), LDL-C (P = 0.003), and triglyceride (P < 0.001) decreased following n-3 PUFA administration. N-3 PUFAs decreased the size of very low-density lipoprotein (VLDL; P < 0.001) particles, but did not affect LDL or high-density lipoprotein (HDL) particles. The concentration of large LDL increased, whereas small LDL decreased, causing the large to small LDL ratio to increase significantly (P = 0.042). Large VLDL and chylomicron concentrations significantly decreased, as did the large to small VLDL ratio (all P < 0.001). FPG levels unchanged, whereas HbA1c levels slightly increased. LPIR scores improved significantly (P = 0.001).

Conclusions

N-3 PUFAs partly improved atherogenic lipoprotein particle size and concentration, and produced less atherogenic lipoprotein subclass ratios in patients that achieved target LDL-C levels and glycemic control. These results suggest that n-3 PUFAs may reduce residual cardiovascular risk factors in statin-treated patients with type 2 diabetes and hypertriglyceridemia.

Trial registration

The study was registered at UMIN-ID: UMIN000013776.

Electronic supplementary material

The online version of this article (10.1186/s12944-018-0706-8) contains supplementary material, which is available to authorized users.

A cross-sectional and longitudinal study between association of n-3 polyunsaturated fatty acids derived from fish consumption and high-density lipoprotein heterogeneity

Decreased high-density lipoprotein (HDL) particle size, cholesterol poor, apolipoprotein A-I-rich HDL particles leading to smaller HDL particle size, may be associated with an anti-atherosclerotic effect. The data are sparse regarding the relationship between n-3 polyunsaturated fatty acids [n-3 PUFAs: eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA)] and HDL particle size. This study was designed as a hospital-based cross-sectional study to investigate the relationship between the serum levels of n-3 PUFAs and the HDL-cholesterol/apolipoprotein A-1 ratio, as estimated by the HDL particle size, in patients with the presence of one or more risk factors for atherosclerotic cardiovascular disease (ASCVD). Six hundred and forty sequential patients were enrolled in this study. The serum levels of EPA and DHA showed a strong correlation (r = 0.736, p < 0.0001). However, in a multivariate regression analysis after adjustment for ASCVD risk factors, increased serum DHA (β = - 0.745, p = 0.021), but not serum EPA (β = - 0.414, p = 0.139) or EPA + DHA (β = 0.330, p = 0.557) level, was identified as an independent indicator of decreased HDL particle size. In 476 patients followed up for at least 6 months, the absolute change (Δ) in the HDL-cholesterol/apolipoprotein A-1 ratio decreased significantly as the quartile of the Δ DHA level increased (p = 0.014), whereas no significant difference in the Δ HDL-cholesterol/apolipoprotein A-1 ratio was noted with the increase in the quartile of the Δ EPA level. Moreover, a multivariate regression analysis identified increased DHA level and decreased estimated low-density lipoprotein (LDL) particle size measured relative to the mobility value of LDL with polyacrylamide gel electrophoresis (i.e., relative LDL migration: LDL-Rm value), as independent predictors of decreased HDL-cholesterol/apolipoprotein A-1 ratio (β = - 0.171, p = 0.0003 and β = - 0.142, p = 0.002). The results suggest that increased serum DHA level, but not EPA level, might be associated with decreased HDL-cholesterol/apolipoprotein A-1 ratio, an indicator of estimated HDL particle size. Further studies are needed to investigate the useful clinical indices and outcomes of these patients. Clinical Trial Registration Information UMIN ( http://www.umin.ac.jp/ ), Study ID: UMIN000010603.

Omega-3 carboxylic acids monotherapy and combination with statins in the management of dyslipidemia

The 2013 American College of Cardiology/American Heart Association guidelines on cholesterol management placed greater emphasis on statin therapy given the well-established benefits in primary and secondary prevention of cardiovascular disease. Residual risk may remain after statin initiation, in part because of triglyceride-rich lipoprotein cholesterol. Several large trials have failed to show benefit with non-statin cholesterol-lowering medications in the reduction of cardiovascular events. Yet, subgroup analyses showed a benefit in those with hypertriglyceridemia and lower high-density lipoprotein cholesterol level, a high-risk pattern of dyslipidemia. This review discusses the benefits of omega-3 carboxylic acids, a recently approved formulation of omega-3 fatty acid with enhanced bioavailability, in the treatment of dyslipidemia both as monotherapy and combination therapy with a statin.

The future of n-3 polyunsaturated fatty acid therapy

PURPOSE OF REVIEW

This article focuses on the potential role by which a complex mixture of omega-3 fatty acids (OM3-FAs) may beneficially modify cardiovascular risk by modifying the cholesterol composition of atherogenic lipoproteins. This hypothesis is being tested in the STRENGTH trial, which is enrolling 13 000 patients on statins at high cardiovascular risk with hypertriglyceridemia and low HDL cholesterol (HDL-C) treated with an OM3-carboxylic acid.

RECENT FINDINGS

Complex mixtures of OM3-FAs containing predominately eicosapentanoic acid and docosahexanoic acid in combination with statins lowers non-HDL by reducing triglyceride-rich lipoprotein cholesterol (TRL-C) while shifting small LDL cholesterol (LDL-C) to large LDL-C. Recent genomic and epidemiological studies have implicated TRL-C and small LDL-C as causal for cardiovascular disease. Therefore OM3-FAs containing both eicosapentanoic acid and docosahexanoic acid in combination with statins may beneficially modify the high residual risk for patients with hypertriglyceridemia and low HDL-C.

SUMMARY

Although outcome trials are underway, subgroup analyses of data from previous randomized controlled trials are suggestive of a reduction in coronary artery disease and atherosclerotic cardiovascular disease event rates with triglyceride and TRL-C lowering therapies, particularly if accompanied by low HDL-C. Although the limitations of such data are acknowledged, clinicians must make treatment decisions while awaiting more definitive results from well-designed large-scale randomized controlled trials.

TRIGLYCERIDES, ATHEROSCLEROSIS, AND CARDIOVASCULAR OUTCOME STUDIES: FOCUS ON OMEGA-3 FATTY ACIDS

OBJECTIVE

To provide an overview of the roles of triglycerides and triglyceride-lowering agents in atherosclerosis in the context of cardiovascular outcomes studies.

METHODS

We reviewed the published literature as well as ClinicalTrials.gov entries for ongoing studies.

RESULTS

Despite improved atherosclerotic cardiovascular disease (ASCVD) outcomes with statin therapy, residual risk remains. Epidemiologic data and recent genetic insights provide compelling evidence that triglycerides are in the causal pathway for the development of atherosclerosis, thereby renewing interest in targeting triglycerides to improve ASCVD outcomes. Fibrates, niacin, and omega-3 fatty acids (OM3FAs) are three classes of triglyceride-lowering drugs. Outcome studies with triglyceride-lowering agents have been inconsistent. With regard to OM3FAs, the JELIS study showed that eicosapentaenoic acid (EPA) significantly reduced major coronary events in statin-treated hypercholesterolemic patients. Regarding other agents, extended-release niacin and fenofibrate are no longer recommended as statin add-on therapy (by some guidelines, though not all) because of the lack of convincing evidence from outcome studies. Notably, subgroup analyses from the outcome studies have generated the hypothesis that triglyceride lowering may provide benefit in statin-treated patients with persistent hypertriglyceridemia. Two ongoing OM3FA outcome studies (REDUCE-IT and STRENGTH) are testing this hypothesis in high-risk, statin-treated patients with triglyceride levels of 200 to 500 mg/dL.

CONCLUSION

There is consistent evidence that triglycerides are in the causal pathway of atherosclerosis but inconsistent evidence from cardiovascular outcomes studies as to whether triglyceride-lowering agents reduce cardiovascular risk. Ongoing outcomes studies will determine the role of triglyceride lowering in statin-treated patients with high-dose prescription OM3FAs in terms of improved ASCVD outcomes.

ABBREVIATIONS

AACE = American Association of Clinical Endocrinologists ACCORD = Action to Control Cardiovascular Risk in Diabetes AIM-HIGH = Atherothrombosis Intervention in Metabolic Syndrome with Low HDL/High Triglycerides: Impact on Global Health Outcomes apo = apolipoprotein ASCEND = A Study of Cardiovascular Events in Diabetes ASCVD = atherosclerotic cardiovascular disease BIP = Bezafibrate Infarction Prevention CHD = coronary heart disease CI = confidence interval CV = cardiovascular CVD = cardiovascular disease DHA = docosahexaenoic acid DO-IT = Diet and Omega-3 Intervention Trial EPA = eicosapentaenoic acid FIELD = Fenofibrate Intervention and Event Lowering in Diabetes GISSI-HF = GISSI-Heart Failure HDL-C = high-density-lipoprotein cholesterol HPS2-THRIVE = Heart Protection Study 2-Treatment of HDL to Reduce the Incidence of Vascular Events HR = hazard ratio JELIS = Japan Eicosapentaenoic Acid Lipid Intervention Study LDL = low-density lipoprotein LDL-C = low-density-lipoprotein cholesterol MI = myocardial infarction OM3FAs = omega-3 fatty acids VITAL = Vitamin D and Omega-3 Trial.

Icosapent ethyl (eicosapentaenoic acid ethyl ester): Effects on plasma apolipoprotein C-III levels in patients from the MARINE and ANCHOR studies

BACKGROUND

Apolipoprotein C-III (ApoC-III) regulates lipoprotein and triglyceride (TG) metabolism and may have a causal role in cardiovascular disease. In the Multi-Center, Placebo-Controlled, Randomized, Double-Blind, 12-Week Study With an Open-Label Extension (MARINE) and ANCHOR studies, icosapent ethyl, a high-purity prescription eicosapentaenoic acid ethyl ester, reduced TG, and other atherogenic lipid parameters without increasing low-density lipoprotein cholesterol (LDL-C) compared with placebo.

OBJECTIVE

To evaluate the effects of icosapent ethyl on plasma ApoC-III levels in patients from 2 phase 3 studies.

METHODS

MARINE and ANCHOR were 12-week double-blind studies of icosapent ethyl in adult patients. Patients in MARINE had very high TG levels (≥500 and ≤2000 mg/dL) and patients in ANCHOR had high TG levels (≥200 and <500 mg/dL) despite statin control of LDL-C. This post hoc analysis of MARINE and ANCHOR assessed the median percent change from baseline in plasma ApoC-III levels vs placebo and includes subgroup analyses by statin use/efficacy and median ApoC-III levels.

RESULTS

We assessed ApoC-III levels in 148 and 612 patients in the MARINE and ANCHOR studies, respectively. In MARINE, the approved prescription dose of icosapent ethyl (4 g/day) significantly reduced ApoC-III levels by 25.1% (P < .0001) vs placebo. In ANCHOR, icosapent ethyl 4 g/day significantly reduced ApoC-III levels by 19.2% (P < .0001) vs placebo; subanalysis by statin efficacy revealed significant reductions vs placebo in the higher-efficacy and medium-efficacy groups (24.6% and 17.2%, respectively; both P < .0001).

CONCLUSION

Icosapent ethyl 4 g/day significantly reduced plasma ApoC-III levels in patients with elevated TGs from the MARINE and ANCHOR studies.