Mineral oil: safety and use as placebo in REDUCE-IT and other clinical studies

Cardiovascular disease in diabetes, beyond glucose

Despite the decades-old knowledge that diabetes mellitus is a major risk factor for cardiovascular disease, the reasons for this association are only partially understood. While this association is true for both type 1 and type 2 diabetes, different pathophysiological processes may be responsible. Lipids and other risk factors are indeed important, whereas the role of glucose is less clear. This lack of clarity stems from clinical trials that do not unambiguously show that intensive glycemic control reduces cardiovascular events. Animal models have provided mechanisms that link diabetes to increased atherosclerosis, and evidence consistent with the importance of factors beyond hyperglycemia has emerged. We review clinical, pathological, and animal studies exploring the pathogenesis of atherosclerosis in humans living with diabetes and in mouse models of diabetes. An increased effort to identify risk factors beyond glucose is now needed to prevent the increased cardiovascular disease risk associated with diabetes.

Beneficial Outcomes of Omega-6 and Omega-3 Polyunsaturated Fatty Acids on Human Health: An Update for 2021

Oxidative stress and inflammation have been recognized as important contributors to the risk of chronic non-communicable diseases. Polyunsaturated fatty acids (PUFAs) may regulate the antioxidant signaling pathway and modulate inflammatory processes. They also influence hepatic lipid metabolism and physiological responses of other organs, including the heart. Longitudinal prospective cohort studies demonstrate that there is an association between moderate intake of the omega-6 PUFA linoleic acid and lower risk of cardiovascular diseases (CVDs), most likely as a result of lower blood cholesterol concentration. Current evidence suggests that increasing intake of arachidonic acid (up to 1500 mg/day) has no adverse effect on platelet aggregation and blood clotting, immune function and markers of inflammation, but may benefit muscle and cognitive performance. Many studies show that higher intakes of omega-3 PUFAs, especially eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are associated with a lower incidence of chronic diseases characterized by elevated inflammation, including CVDs. This is because of the multiple molecular and cellular actions of EPA and DHA. Intervention trials using EPA + DHA indicate benefit on CVD mortality and a significant inverse linear dose-response relationship has been found between EPA + DHA intake and CVD outcomes. In addition to their antioxidant and anti-inflammatory roles, omega-3 fatty acids are considered to regulate platelet homeostasis and lower risk of thrombosis, which together indicate their potential use in COVID-19 therapy.

A Fishy Topic: VITAL, REDUCE-IT, STRENGTH, and Beyond: Putting Omega-3 Fatty Acids into Practice in 2021

PURPOSE OF REVIEW

To examine recently published data from clinical outcome and arteriographic studies that examined the addition of omega-3 fatty acids, eicosapentaenoic acid (EPA) + docosahexanoic acid (DHA), to standard of care therapy on cardiovascular disease (CVD) risk.

RECENT FINDINGS

Several trials that tested purified EPA (JELIS, REDUCE-IT, EVAPORATE) were associated with reduced CVD risk and regression of low attenuation coronary plaque volume, whereas studies that employed the combination EPA/DHA (VITAL, OMEMI, STRENGTH) failed to derive clinical benefit. Trials testing purified EPA consistently demonstrated reduction in atheromatous volume or CVD events beyond standard of care therapies, whereas the combination of EPA/DHA did not, despite producing similar reductions in triglycerides. Experimental and in vitro data suggest that compared to DHA, EPA exhibits antioxidant, anti-inflammatory, and membrane stabilizing properties that enhance vascular function and CVD risk. Consequently, purified EPA appears to be the treatment of choice for high-risk patients with hypertriglyceridemia.

Triglyceride-Rich Lipoprotein Remnants and Cardiovascular Disease

BACKGROUND

Triglycerides, cholesterol, and their metabolism are linked due to shared packaging and transport within circulating lipoprotein particles. While a case for a causal role of cholesterol-carrying low-density lipoproteins (LDLs) in atherosclerosis is well made, the body of scientific evidence for a causal role of triglyceride-rich lipoproteins (TRLs) is rapidly growing, with multiple lines of evidence (old and new) providing robust support.

CONTENT

This review will discuss current perspectives and accumulated evidence that an overabundance of remnant lipoproteins stemming from intravascular remodeling of nascent TRLs-chylomicrons and very low-density lipoproteins (VLDL)-results in a proatherogenic milieu that augments cardiovascular risk. Basic mechanisms of TRL metabolism and clearance will be summarized, assay methods reviewed, and pivotal clinical studies highlighted.

SUMMARY

Remnant lipoproteins are rendered highly atherogenic by their high cholesterol content, altered apolipoprotein composition, and physicochemical properties. The aggregate findings from multiple lines of evidence suggest that TRL remnants play a central role in residual cardiovascular risk.

Secondary data analysis investigating effects of marine omega-3 fatty acids on circulating levels of leptin and adiponectin in older adults

BACKGROUND

Higher leptin and lower adiponectin levels have been linked to progressing systemic inflammation and diseases of aging. Among older adults with obesity and an inflammatory conditions, we quantified effects of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) supplementation on leptin, adiponectin, and the leptin-to-adiponectin ratio (LAR). We also examined associations among adipokine and cytokine levels.

METHODS

Using a randomized, double-blind, placebo-controlled design, participants (mean age 61.3 ± 2.1) received 1.5 g EPA + 1.0 g DHA (n = 14) or mineral oil (n = 18) daily. Plasma adipokine and cytokine levels were quantified by electrochemiluminescence at all study intervals.

RESULTS

While no between-group differences were detected, there was a reduction in the LAR (by 23%, p=.065) between weeks 4 and 8 among the EPA+DHA group. Adiponectin levels were negatively associated with IL-1β levels at week 4 (p=.02) and TNF-α levels at week 8 (p=.03).

CONCLUSION

Potential benefits of EPA+DHA supplementation among aging populations warrant further study.

Update on the omega-3 fatty acid trial landscape: A narrative review with implications for primary prevention

Residual risk mediated by hypertriglyceridemia among statin-treated individuals is an important clinical and public health challenge. Niacin, fibrates and omega-3 FA are three classes of non-statin agents with demonstrated TG-lowering effects. Randomized controlled trials of niacin and fibrates have been consistently negative, but the trial landscape for two key sources of omega-3 FAs, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) is more complex. Clinical trials evaluating omega-3 FA can be differentiated into those that studied mixed formulations (EPA + DHA) and those that studied EPA alone. Those assessing the impact of mixed formulations have not consistently demonstrated CVD risk reduction, whereas trials of EPA alone have been successful. Two recent trials of mixed formulations - STRENGTH (Long-Term Outcomes Study to Assess Statin Residual Risk with Epanova in High Cardiovascular Risk Patients with Hypertriglyceridemia) and OMEMI (Omega-3 fatty acids in Elderly patients with Myocardial Infarction) - studied contemporarily treated patients with mixed EPA + DHA formulations at higher doses than before and showed no benefit, thus adding valuable information to our overall understanding of this evolving therapeutic class. In this review, we contextualize the findings of STRENGTH and OMEMI within the existing omega-3 FA clinical trial landscape and look ahead to how future trials can inform existing knowledge gaps, particularly with regards to the applicability of these agents within the primary prevention realm.

Managing dyslipidemia in patients with Type 2 diabetes

INTRODUCTION

Type 2 diabetes mellitus (T2DM) is associated with increased risk for atherosclerotic cardiovascular disease (ASCVD) which is partly related to atherogenic dyslipidemia with raised triglycerides, reduced high-density lipoprotein cholesterol levels, and accompanying lipid changes. Treatment of this dyslipidemia is regarded as a priority to reduce the ASCVD risk in T2DM.

AREAS COVERED

This article reviews the relevant studies and guidelines from the publications related to this area.

EXPERT OPINION

Lifestyle modification should always be encouraged, and statin treatment is indicated in most patients with T2DM based on the outcome of randomized controlled trials. If LDL-C goals are not achieved, first, ezetimibe and subsequently proprotein convertase subtilisin-kexin type 9 (PCSK9) inhibitors should be added. Patients with T2DM derive greater benefits from ezetimibe and PCSK9 inhibitors due to their higher absolute ASCVD risk compared to patients without T2DM. If triglyceride levels remain elevated, a high dose of eicosapentaenoic acid ethyl ester should be added. Fibrates should be used for severe hypertriglyceridemia to prevent acute pancreatitis. Novel treatments including pemafibrate and inclisiran are undergoing cardiovascular outcome trials, and RNA-based therapies may help to target residual hypertriglyceridemia and high lipoprotein(a) with the long acting treatments offering potential improved adherence to therapy.

EPA's pleiotropic mechanisms of action: a narrative review

Treatment with icosapent ethyl 4 g/day, a highly purified and stable ethyl ester of eicosapentaenoic acid (EPA), demonstrated a significant reduction in atherosclerotic cardiovascular disease (ASCVD) events and death in REDUCE-IT. However, analyses of REDUCE-IT and meta-analyses have suggested that this clinical benefit is greater than can be achieved by triglyceride reduction alone. EPA therefore may have additional pleiotropic effects, including anti-inflammatory and anti-aggregatory mechanisms. EPA competes with arachidonic acid for cyclooxygenase and lipoxygenase, producing anti-inflammatory and anti-aggregatory metabolites rather than the more deleterious metabolites associated with arachidonic acid. Changing the EPA:arachidonic acid ratio may shift metabolic status from pro-inflammatory/pro-aggregatory to anti-inflammatory/anti-aggregatory. EPA also has antioxidant effects and increases synthesis of nitric oxide. Incorporation of EPA into phospholipid bilayers influences membrane structure and may help to prevent cardiac arrhythmias. Clinically, this may translate into improved vascular health, including regression of atherosclerotic plaque. Overall, EPA has a range of pleiotropic effects that contribute to a reduction in ASCVD.

Icosapent ethyl: scientific and legal controversies

Icosapent ethyl (Vascepa) is a purified preparation of the omega-3 fatty acid eicosapentaenoic acid, which is marketed by Amarin Pharma based in Ireland. The product was initially approved by the US Food and Drug Administration for the use of a high dose (4 g/day) in the treatment of hypertriglyceridaemia. On the basis of the results of the REDUCE-IT (Reduction of Cardiovascular Events with Icosapent Ethyl Intervention Trial), the agency later granted a label extension to include the additional indication of a reduction in risk of cardiovascular events in persons with serum triglyceride levels of 150 mg/dL or greater and established cardiovascular disease or diabetes. Data supporting the efficacy of omega-3 fatty acids in the prevention of cardiovascular disease have been inconsistent and controversial. The story of the development of icosapent ethyl has been fraught with challenges, including the invalidation of six core patents on the product, and recently, the completion of a new clinical trial, STRENGTH (Long-Term Outcomes Study to Assess STatin Residual Risk Reduction With EpaNova in HiGh CV Risk PatienTs With Hypertriglyceridemia), that directly contradicts REDUCE-IT and calls into question whether icosapent ethyl is actually effective in the secondary prevention of cardiovascular events. This article traces the course of the development of this fascinating product and discusses its complex medical, regulatory and legal history, which is still continuing to unfold.

Coronary heart disease risk: Low-density lipoprotein and beyond

Coronary heart disease (CHD) is the leading cause of morbidity and mortality world-wide and has been characterized as a chronic immunoinflammatory, fibroproliferative disease fueled by lipids. Great advances have been made in elucidating the complex mechanistic interactions among risk factors associated with CHD, yielding abundant success towards preventive measures and the development of pharmaceuticals to prevent and treat CHD via attenuation of lipoprotein-mediated risk. However, significant residual risk remains. Several potentially modifiable CHD risk factors ostensibly contributing to this residual risk have since come to the fore, including systemic inflammation, diabetes mellitus, high-density lipoprotein, plasma triglycerides (TG) and remnant lipoproteins (RLP), lipoprotein(a) (Lp[a]), and vascular endothelial dysfunction (ED). Herein, we summarize the body of evidence implicating each of these risk factors in residual CHD risk.

Fish Oil Supplements for Prevention of Cardiovascular Disease: The Jury Is Still Out: CON: Fish Oil is Useful to Prevent or Treat Cardiovascular Disease

Consumption of oily fish high in omega-3 fatty acids (n-3FAs) is strongly associated with reduced risk of adverse cardiovascular events. Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are the n-3FAs in fish oil believed to confer its beneficial effects. Over the past two decades, multiple clinical trials have been conducted to test the hypothesis that encapsulated EPA and DHA supplements improve cardiovascular outcomes in patients with established cardiovascular disease or at risk of developing it. Over the same time period, over-the-counter fish oil supplements have become a multi-billion-dollar industry. In this article, we briefly review available clinical trial data involving EPA and DHA supplementation. Based on currently available information, we conclude that combination capsules containing EPA and DHA should not be used to reduce cardiovascular risk. Some studies suggest that EPA as stand-alone therapy decreases cardiovascular risk. Nevertheless, we advocate a restrictive approach to using EPA to improve cardiovascular outcomes.