Triglyceride-Rich Lipoproteins and Coronary Artery Disease Risk

Omega-3 fatty acids in the treatment of heart failure

Omega-3 polyunsaturated fatty acids (Ω-3 PUFAs) have garnered increased attention as a therapeutic option in cardiovascular disease. Most of the research to date has focused on their lipid altering effects and clinical benefits in patients with coronary artery disease, however, there are data supporting their use in the treatment of heart failure. We review the mechanisms through which Ω-3 PUFAs exert their positive effects on the cardiovascular system and highlight the observational and treatment studies that assessed their effects in patients with heart failure.

Local and systemic factors associated with quantitative stiffness of carotid plaque

PURPOSE

Plaque stiffness in carotid artery stenosis is a clinically important factor involved in the development of stroke and surgical complications. The purpose of this study was to clarify which local and systemic factors are associated with the quantitatively measured stiffness of plaque.

METHODS

The subjects were 104 consecutive patients who underwent carotid endarterectomy at our institution. To measure quantitative stiffness of plaque, we used an industrial hard meter in the operating room within 1 h after removal of plaque. Local factors related to carotid plaque hardness were evaluated, including maximum intima-media thickness (max IMT), degree of stenosis using the European Carotid Surgery Trial (ECST), presence of ulceration or calcification, and echo brightness on preoperative carotid ultrasound. The degree of stenosis was also evaluated using the North American Symptomatic Carotid Endarterectomy Trial method in digital subtraction angiography. Age, sex, and presence or absence of hypertension, diabetes, and dyslipidemia (low-density lipoprotein cholesterol and triglyceride [TG] levels) served as systemic factors and were compared with the quantitative stiffness of carotid plaque.

RESULTS

In multivariate analysis, ECST stenosis degree, calcification, and IMT max as local factors affected plaque stiffness. As a systemic factor, plaque stiffness was statistically significantly negatively correlated with TG values in multivariate analysis (p < 0.05).

CONCLUSION

The quantitative stiffness of the plaque was negatively correlated with TG levels as a systemic factor in addition to local factors. This might suggest that reducing high TG levels is associated with plaque stabilization.

Endothelial Function in Dyslipidemia: Roles of LDL-Cholesterol, HDL-Cholesterol and Triglycerides

Dyslipidemia is associated with endothelial dysfunction. Endothelial dysfunction is the initial step for atherosclerosis, resulting in cardiovascular complications. It is clinically important to break the process of endothelial dysfunction to cardiovascular complications in patients with dyslipidemia. Lipid-lowering therapy enables the improvement of endothelial function in patients with dyslipidemia. It is likely that the relationships of components of a lipid profile such as low-density lipoprotein cholesterol, high-density lipoprotein cholesterol and triglycerides with endothelial function are not simple. In this review, we focus on the roles of components of a lipid profile in endothelial function.

Increased residual cardiovascular risk in U.S. veterans with moderately-elevated baseline triglycerides and well-controlled LDL-C levels on statins

Background

Recent studies have demonstrated a causal role for elevated triglycerides (TG) in incident cardiovascular (CV) events in patients with established coronary heart disease (CHD) and those with CV risk factors alone, particularly diabetes.

Objective

Using a large cohort of U.S. veterans with statin-controlled LDL-C levels (40–100 mg/dL), we explored residual CV risk among patients with elevated baseline TG levels (150–499 mg/dL) vs. those with normal TG levels (<150 mg/dL).

Methods

We identified veterans receiving a statin but not a TG-lowering agent from the VA electronic health records database, from 2010 to 2015. We compared composite CV event rates (MI, stroke, unstable angina, coronary revascularization, and CV death) between the elevated TG and normal TG groups. We stratified the study cohort according to 3 CV risk groups: (1) no diabetes and no prior CV event, (2) diabetes and no prior CV event, and (3) prior CV event. We calculated crude event rates, rate ratios, and event rate ratios adjusted for age, sex, systolic blood pressure, estimated glomerular filtration rate, and weight.

Results

The cohort included 396,189 veterans (predominantly male and white) of whom 109,195 (28%) had elevated TG levels. Those with elevated TG were younger (age 73 vs. 77 years) and had a higher body mass index (31.3 vs. 28.3 Kg/M²). The overall composite crude and adjusted rate ratios comparing the elevated and normal TG groups were 1.10 (1.09, 1.12) and 1.05 (1.03, 1.06), respectively. For CV risk groups 1, 2 and 3, the adjusted rate ratios comparing the elevated and normal TG groups were 0.99 (0.96, 1.02), 1.05 (1.02, 1.08), and 1.07 (1.04, 1.10), respectively. An association of increased rate ratios did not hold for fatal events.

Conclusion

Those with elevated TG levels and well-controlled LDL-C on statins showed a modest increase in CV events compared to those with normal TG. Elevated TG levels were associated with increased CV events in patients with established CV disease and with diabetes only, suggesting that elevated TG levels are associated with a similar degree of residual risk in high-risk primary prevention and secondary prevention settings.

The Influence of SARS-CoV-2 Infection on Lipid Metabolism—The Potential Use of Lipid-Lowering Agents in COVID-19 Management

Several studies have indicated lipid metabolism alterations during COVID-19 infection, specifically a decrease in high-density lipoprotein (HDL) and low-density lipoprotein (LDL) concentrations and an increase in triglyceride (TG) levels during the infection. However, a decline in triglycerides can also be observed in critical cases. A direct correlation can be observed between a decrease in serum cholesterol, HDL-C, LDL-C and TGs, and the severity of the disease; these laboratory findings can serve as potential markers for patient outcomes. The transmission of coronavirus increases proportionally with rising levels of cholesterol in the cell membrane. This is due to the fact that cholesterol increases the number of viral entry spots and the concentration of angiotensin-converting enzyme 2 (ACE2) receptor, crucial for viral penetration. Studies have found that lower HDL-C levels correspond with a higher susceptibility to SARS-CoV-2 infection and infections in general, while higher HDL-C levels were related to a lower risk of developing them. However, extremely high HDL-C levels in serum increase the risk of infectious diseases and is associated with a higher risk of cardiovascular events. Low HDL-C levels are already accepted as a marker for risk stratification in critical illnesses, and higher HDL-C levels prior to the infection is associated with a lower risk of death in older patients. The correlation between LDL-C levels and disease severity is still unclear. However, TG levels were significantly higher in non-surviving severe patients compared to those that survived; therefore, elevated TG-C levels in COVID-19 patients may be considered an indicator of uncontrolled inflammation and an increased risk of death.

Self- vs provider-referral differences for coronary artery calcium testing

Study objectives

The objectives of this study were to identify independent predictors for moderate/accentuated coronary artery calcium (CAC) score and compare patients who self-referred for CAC Computed Tomography (CT) testing to those who were provider-referred.

Design

Patients underwent CAC between January to July 2019. The analysis was divided into self-referred patients influenced by a CAC community campaign who identified themselves as having cardiovascular risk factors compared to provider-referred intermediate-risk patients who were asymptomatic. SAS version 9.4 (SAS Institute, Inc., Cary, NC) was used for all analyses.

Setting

Seven southwest Ohio hospitals from a single network.

Participants

2124 adult patients who received CAC CT (163 self and 1961 provider-referred).

Interventions

CAC CT.

Main outcome measures

Demographics, risk factors, lab values, prescriptions, and referral status were used to compare CAC score differences between self- and provider-referred patients.

Results

For 2124 patients, three predictors for moderate/accentuated CAC score remained significant after multiple logistic regression: CKD (OR 0.24, CI 0.008-0.68, p < 0.05), COPD (OR 0.39, CI 0.19-0.80, p < 0.05), and CAD (OR 0.46, CI 0.22-0.98, p < 0.05). There were four differences between referred groups: history of PVD (OR 0.21, CI 0.05-0.86, p < 0.05), higher triglyceride (OR 1.004, CI 1.00-1.01, p < 0.05), higher LDL levels (OR 0.991, CI 0.98-1.00, p < 0.05), and beta blocker prescription (OR 4.38, CI 1.49-12.85, p < 0.05) in self-referred patients.

Conclusions

CAC CT testing is associated with independent risk predictors and can be used to clarify cardiovascular risk in self- and provider-referred patients with statistical similarity. Patients reliably self-refer for CAC CT when risk is present during a community initiative. Such initiatives may have a preventive benefit and lead to earlier pursuit and optimization of anti-lipid therapies.

Egyptian practical guidance in hypertriglyceridemia management 2021

Hypertriglyceridemia (HTG) is a very common, yet underappreciated problem in clinical practice. Elevated triglyceride (TG) levels are independently associated with atherosclerotic cardiovascular disease (ASCVD) risk. Furthermore, severe HTG may lead to acute pancreatitis. Although LDL-guided statin therapy has improved ASCVD outcomes, residual risk remains. Recent trials have demonstrated that management of high TG levels, in patients already on statin therapy, reduces the rate of major vascular events. Few guidelines were issued, providing important recommendations for HTG management strategies. The goal of treatment is to reduce the risk of ASCVD and acute pancreatitis. The management stands on lifestyle modification, detection of secondary causes of HTG and pharmacological therapy, when indicated. In this guidance we review the causes and classification of HTG and summarize the current methods for risk estimation, diagnosis and treatment. The present guidance provides a focused update on the management of HTG, outlined in a simple user-friendly format, with an emphasis on the latest available data.

Association of remnant cholesterol with intra- and extra-cranial atherosclerosis in Chinese community population

Background

Multifocal atherosclerosis has dramatically increased annual risk of adverse cardiovascular events than single artery affected. Triglyceride-rich lipoprotein (TRL) has been implicated in the early development of atherosclerosis.However, evidence on the effect of remnant cholesterol, a major atherogenic component of TRL, on multifocal atherosclerosis in Chinese health asymptomatic subjects is insufficient. This study aimed to investigate the association of remnant cholesterol with intra- and extra-cranial atherosclerosis in Chinese population.

Methods

This study enrolled 3665 participants (median age 52.31 years) from the Asymptomatic Polyvascular Abnormalities Community study. Parameters of intra- and extra-cranial atherosclerosis includes intracranial artery stenosis (ICAS), carotid plaque, carotid artery stenosis (CAS), and carotid hypertrophy (intima-media thickness >0.9 mm). Logistic regression was used to assess these associations.

Results

The prevalence of vascular atherosclerosis significantly increased with increasing remnant cholesterol quartiles (P for trend <0.0001). In the multivariable-adjusted model, the odds ratio with 95% confidence interval comparing participants in Q4 versus Q1 of remnant cholesterol was 1.73 (1.29-2.31) for ICAS, 1.54 (1.22-1.94) for carotid plaque, 1.47 (1.17-1.84) for CAS, and 1.93 (1.48-2.52) for carotid hypertrophy, respectively. Furthermore, multivariable-adjusted spline regression showed S-shaped associations between remnant cholesterol and these outcomes.

Conclusion

Individuals with a high level of remnant cholesterol had a higher risk of intra- and extra-cranial atherosclerosis in Chinese population. Interventions aimed at reducing remnant cholesterol to prevent atherosclerotic diseases warrant further investigations.

High-density lipoproteins (HDL): Novel function and therapeutic applications

The failure of high-density lipoprotein (HDL)-raising agents to reduce cardiovascular disease (CVD) together with recent findings of increased cardiovascular mortality in subjects with extremely high HDL-cholesterol levels provide new opportunities to revisit our view of HDL. The concept of HDL function developed to explain these contradictory findings has recently been expanded by a role played by HDL in the lipolysis of triglyceride-rich lipoproteins (TGRLs) by lipoprotein lipase. According to the reverse remnant-cholesterol transport (RRT) hypothesis, HDL critically contributes to TGRL lipolysis via acquirement of surface lipids, including free cholesterol, released from TGRL. Ensuing cholesterol transport to the liver with excretion into the bile may reduce cholesterol influx in the arterial wall by accelerating removal from circulation of atherogenic, cholesterol-rich TGRL remnants. Such novel function of HDL opens wide therapeutic applications to reduce CVD in statin-treated patients, which primarily involve activation of cholesterol flux upon lipolysis.

Triglycerides and cardiovascular disease

PURPOSE OF REVIEW

Triglycerides (TGs) are measured as part of routine lipid profiles but their relationship to cardiovascular disease (CVD) risk has been controversial and overshadowed by high-density lipoprotein cholesterol (HDL-C).

RECENT FINDINGS

Epidemiological studies show a clear relationship of TG-containing lipoproteins including remnant particles with CVD risk with the effect being most clearly demonstrated through the excess risk captured by non-HDL-C compared with low-density lipoprotein-cholesterol (LDL-C). Mendelian randomisation studies show a consistent relationship of gene variants linked to TG metabolism with rates of CVD. Furthermore, meta-analyses of intervention trials with statins and other nonstatin drugs also suggest that reducing TGs is associated with benefits on rates of CVD events. Historical subgroup data from fibrate trials suggest benefits in patients with high TG:HDL ratios but seem to add little to optimized statin therapy. Recent trials with omega-3 fatty acids (specifically eicosapentaenoic acid) have suggested that high-dose formulations in contrast to low dose formulations have benefits on CVD outcomes.

SUMMARY

Further studies with newer agents are required to determine the place of TG-lowering drugs in therapeutic pathways. Trials with agents such as pemafibrate and vupanorsen may finally answer these questions.

Lower triglyceride levels are associated with better endothelial function

BACKGROUND

Increased serum triglyceride levels are independently associated with endothelial dysfunction. However, there is little evidence to define normal levels of triglycerides and there is little information on endothelial function in subjects with extremely low levels of triglycerides.

OBJECTIVE

The purpose of this study was to determine the relationship between triglycerides, especially low levels of triglycerides, and vascular function.

METHODS

We measured flow-mediated vasodilation (FMD) in 7047 subjects and nitroglycerine-induced vasodilation (NID) in 1017 subjects. We divided the subjects into eight groups by triglyceride levels: <50 mg/dL, 50-69 mg/dL, 70-89 mg/dL, 90-109 mg/dL, 110-129 mg/dL, 130-149 mg/dL, 150-199 mg/dL, and ≥200 mg/dL.

RESULTS

FMD was significantly higher in subjects with triglyceride levels of <50 mg/dL than in subjects with triglyceride levels of 50-69 mg/dL, 70-89 mg/dL, 90-109 mg/dL, 110-129 mg/dL, 130-149 mg/dL, 150-199 mg/dL, and ≥200 mg/dL (p=0.002, p<0.001, p<0.001, p<0.001, p<0.001, p<0.001, and p<0.001, respectively). Using triglyceride levels of >200 mg/dL as a reference, the odds ratios for a lower quartile of FMD were significantly lower in the <50 mg/dL group, 50-69 mg/dL group, 70-89 mg/dL group, and 90-109 mg/dL group after adjustment for age, gender and other cardiovascular risk factors. There was a slight negative correlation between NID and triglycerides (r=-0.074; p=0.019). However, there was no significant differences in NID among the eight groups.

CONCLUSIONS

FMD values were highest in subjects with extremely low levels of triglycerides (<50 mg/dL). Lower triglyceride levels were associated with better endothelial function.

CLINICAL TRIAL REGISTRATION INFORMATION

http://www.umin.ac.jp (University Hospital Medical Information Network Clinical Trials Registry) (UMIN000012950).

When to lower triglycerides?

PURPOSE OF REVIEW

Substantial risk of ASCVD events persists despite intensive statin therapy and other agents to lower LDL-C. The optimal way to address other elements of dyslipidemia, such as triglyceride-rich particles (TRL) and when to treat has remained unclear.

RECENT FINDINGS

Several lines of evidence indicate that TRL are associated with atherogenesis, partly because of associated factors, such as cholesterol-enriched remnant particles, high LDL particle number, high apo-B, high apo-CIII, and others. High triglyceride is increasingly prevalent because of worsening of lifestyle factors, obesity, and diabetes. Trials with fibrates, and niacin to reduce residual dyslipidemia have not provided evidence of benefits after statin therapy, thus far. A recent trial with an omega 3 fatty acid (OM3FA), icosapent-ethyl (IPE), provided evidence for a 25% reduction in ASCVD events in statin-treated high-risk population. These results were unexplained by triglyceride reduction alone, and are likely related to unique biologic effects of IPE on atherosclerosis. Finally, in patients with very high triglycerides, lifestyle measures and several triglyceride-lowering agents are indicated, often in combination, to prevent episodes of pancreatitis. A novel Apo C-III inhibitor may provide additional benefit in such patients.

SUMMARY

There is evidence for the benefits of IPE in preventing ASCVD events. A novel fibrate is in clinical trials.

Prognostic impact of estimated remnant-like particle cholesterol in patients with differing glycometabolic status: an observational cohort study from China

Background

It is uncertain whether estimated remnant-like particle cholesterol (RLP-C) could predict residual risk in patients with different glycometabolic status. This study aimed to evaluate the relationship between estimated RLP-C and adverse prognosis in patients with non-ST-segment elevation acute coronary syndrome (NSTE-ACS) treated with percutaneous coronary intervention (PCI) and to identify the potential impact of glycometabolism on the predictive value of estimated RLP-C.

Methods

The study assessed 2419 participants with NSTE-ACS undergoing PCI at Beijing Anzhen Hospital from January to December 2015. Estimated RLP-C was calculated as follows: total cholesterol (TC) minus low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C). The adverse events included all-cause death, non-fatal myocardial infarction (MI), and ischemia-driven revascularization.

Results

Estimated RLP-C was prominently associated with adverse prognosis in the total population [hazard ratio (HR) 1.291 per 1-SD increase, 95% confidence interval (CI) 1.119–1.490, P <  0.001], independent of confounding risk factors. However, subgroup analysis showed that increasing estimated RLP-C was related to a higher risk of adverse events in the diabetic population only [HR 1.385 per 1-SD increase, 95% CI 1.183–1.620, P <  0.001]. Estimated RLP-C failed to be a significant determinant of adverse prognosis in non-diabetic and pre-diabetic subgroups. The addition of estimated RLP-C to a baseline model including traditional risk factors enhanced the predictive performance both in total and diabetic populations.

Conclusions

High estimated RLP-C level is a significant predictor for recurrent adverse events in patients with diabetes and NSTE-ACS treated with PCI.

Fibrate pharmacogenomics: expanding past the genome

Fibrates are a medication class prescribed for decades as 'broad-spectrum' lipid-modifying agents used to lower blood triglyceride levels and raise high-density lipoprotein cholesterol levels. Such lipid changes are associated with a decrease in cardiovascular disease, and fibrates are commonly used to reduce risk of dangerous cardiovascular outcomes. As with most drugs, it is well established that response to fibrate treatment is variable, and this variation is heritable. This has motivated the investigation of pharmacogenomic determinants of response, and multiple studies have discovered a number of genes associated with fibrate response. Similar to other complex traits, the interrogation of single nucleotide polymorphisms using candidate gene or genome-wide approaches has not revealed a substantial portion of response variation. However, recent innovations in technological platforms and advances in statistical methodologies are revolutionizing the use and integration of other 'omes' in pharmacogenomics studies. Here, we detail successes, challenges, and recent advances in fibrate pharmacogenomics.

Study on Effects and Mechanism of Lead and High-Fat Diet on Cognitive Function and Central Nervous System in Mice

OBJECTIVE

We sought to investigate the effects and mechanism of lead and a high-fat diet on cognitive function and the central nervous system in mice.

METHODS

Eighty-four healthy male mice were randomly divided into a control group (n = 21) (fed with common diet and free drinking), a lead exposure group (n = 21) (fed with common diet and 300 mg/L lead acetate solution), a high-fat group (n = 21) (fed with high-fat diet and free drinking), and a lead + high-fat group (n = 21) (fed with high-fat diet and 300 mg/L lead acetate solution). In 10 weeks after lead exposure, the mice of all groups were tested for the cognition, learning and memory abilities, body weight, serum triglyceride (TG), low-density lipoprotein, and high-density lipoprotein, as well as for the contents of lead, interleukin 6 (IL-6), interleukin 17 (IL-17), interferon γ, advanced glycation end products (AGEs), glutathione S-transferase (GSH-ST), and hydrogen peroxide in the brain tissues.

RESULTS

Compared with the control group and the lead-exposed group, the body weights of mice in the high-fat group and the lead + high-fat group increased significantly from the sixth week of the experiment, of which the difference was statistically significant (P < 0.05). Compared with the control group and the high-fat group, the lead content in brain tissue of the lead exposure group and the lead + high-fat group increased significantly, of which the difference was statistically significant (P < 0.05). Compared with the control group, the escape latent period, triglyceride, low-density lipoprotein, IL-6, IL-17, interferon γ, and AGEs of the remaining 3 groups increased significantly, but the recognition index, passing platform times, high-density lipoprotein, and GSH-ST significantly decreased (P < 0.05); the second and third escape latent periods, IL-6, IL-17, and AGEs of lead + high-fat group, were obviously higher than the remaining 3 groups, but the passing platform times were obviously lower than the remaining 3 groups, of which the difference was statistically significant. The content of hydrogen peroxide in brain tissues had no difference among groups (P > 0.05).

CONCLUSIONS

The lead and high-fat diet resulted in lipid metabolism disorders and impaired the cognitive function and central nervous system by promoting the secretion of inflammatory factors in glial cells, inducing the inflammatory reaction of brain tissue, inhibiting GSH-ST expression, and increasing AGEs content.

Rosa rugosa flavonoids exhibited PPARα agonist-like effects on genetic severe hypertriglyceridemia of mice

ETHNOPHARMACOLOGICAL RELEVANCE

Rosa rugosa Thunb. is a traditional Chinese medicine that was used in the treatment of cardiovascular diseases and relative risk factors such as diabetes, hyperlipidemia, hypertension, and inflammation. Rosa rugosa flavonoids (RRFs) are the main components in Rosa rugosa Thunb. Several studies have demonstrated that RRFs can regulate plasma lipid contents, but the related mechanism of which has not yet been elucidated clearly.

AIM OF THE STUDY

The goal of this study was to clarify the effects of RRFs on triglyceride metabolism and its related mechanisms.

MATERIALS AND METHODS

RRFs were obtained by ethanol extraction from Rosa rugosa Thunb.. Transgenic mice expressing human Apolipoprotein C3 (ApoC3) were used as a mouse model of hypertriglyceridemia. Fenofibrate (FNB), a PPARα agonist, was used as a positive control drug of decreasing high triglyceride. FNB (100 mg/kg) or RRFs (300 mg/kg) were given to the mice by gavage daily. Two weeks later, the changes of plasma lipid levels in the mice were measured by commercial kits, the clearance of triglyceride was evaluated by oral fat load test, and expression of the genes related to lipid β-oxidation and synthesis was detected in the mice livers by real time PCR.

RESULTS

RRFs, as well as FNB, were found to significantly reduce plasma triglyceride (TG) levels in ApoC3 transgenic mice after administration of the drug for two weeks. Plasma lipid clearance rate was increased and lipid content in the mice livers was reduced after administration of RRF. Treatment with RRFs up-regulated mRNA expression of PPARα and its downstream gene of ACOX, while down-regulated mRNA expression of the genes related to fatty acid synthesis (FASN, SREBP-1c, and ACC1). The expression of LPL was raised, while the expression of ApoC3 was decreased, and Foxo1 was inhibited by RRFs in the mice livers.

CONCLUSION

RRFs can reduce plasma TG levels by repressing the expression of ApoC3 and inducing the expression of LPL in liver. RRFs could also reduce triglyceride in hepatocytes through increasing β-oxidation and decreasing synthesis of the lipids. These findings show the potency of further clinical application of RRFs as a hypolipidemic drug for treatment of cardiovascular diseases.

Remnant Lipoprotein Cholesterol Independently Associates With In-Stent Restenosis After Drug-Eluting Stenting for Coronary Artery Disease

This study evaluated the prognostic value of remnant lipoprotein cholesterol (RLP-C) as a predictor of in-stent restenosis (ISR) after drug-eluting stent (DES) implantation in patients with coronary artery disease (CAD). Consecutive patients with CAD (n = 612) who underwent both successful coronary DES implantation and follow-up angiography ranging from 6 to 24 months were enrolled. The independent predictors of ISR were explored by multivariate logistic regression analysis; 95 (15.52%) patients were identified to have ISR. Multivariate logistic regression analysis showed that RLP-C concentration (odds ratio [OR]: 4.245, 95% confidence interval [CI]: 2.493-7.229), age (OR: 1.026, 95% CI: 1.002-1.051), diabetes mellitus (DM; OR: 1.811, 95% CI: 1.134-2.892), and lesion length (OR: 1.013, 95% CI: 1.002-1.024) were associated with ISR. Via subgroup analysis, we found that RLP-C was independently associated with ISR in both CAD with DM (OR: 4.154, 95% CI: 1.895-9.104) and CAD without DM (OR: 4.455, 95% CI: 2.097-9.464) groups. In the analysis of the receiver operating characteristics curve, RLP-C level >0.515 mmol/L exhibited 77.9% sensitivity and 56.5% specificity (area under the curve: 0.705, 95% CI: 0.648-0.762) in predicting ISR. In conclusion, RLP-C is independently associated with the development of ISR in patients with CAD after DES implantation.

Elevated triglycerides rather than other lipid parameters are associated with increased urinary albumin to creatinine ratio in the general population of China: a report from the REACTION study

Background

Dyslipidaemia has always been regarded as the cornerstone of arteriosclerosis and is related to the pathogenesis of renal insufficiency. However, it is unclear which routinely available lipid parameter is related to urinary albumin to creatinine ratio (UACR). The purpose of this study was to examine the lipid abnormalities associated with UACR in the general population in China.

Methods

The present study was nested in an ongoing Risk Evaluation of cAncers in Chinese diabetic Individuals: A lONgitudinal (REACTION) study, which was designed to demonstrate the association of abnormal glucose metabolism with the risk of cancer in the Chinese population. This cross-sectional study included 34, 569 subjects (11, 390 males and 23, 179 females) from 8 different regional community cohorts, with an average age of 57.9 years. The UACR data were divided into the < 25% group, the 25–49% group, the 50–74% group, and the ≥ 75% group according to the quartile division of the centre where the subjects visited. The lipid classes were defined according to the guidelines for the prevention and treatment of dyslipidaemia in Chinese adults. Multiple logistic regression analysis was used to evaluate the association of the lipid parameters and UACR.

Results

Multivariable regression analysis revealed that compared with the other lipid parameters, triglycerides (TG) showed an adjusted odds ratio that was significant in model 1–4. This relationship was attenuated after adjusting for Haemoglobin A1c (HbA1c) and blood pressure (BP), but TG ≥ 2.3 mmol/L was still significantly associated with UACR in total subjects and in both men and women (OR: 1.131, 95% CI 1.065–1.203, P < 0.001 in total subjects; OR: 1.134, 95% CI 1.022–1.258, P = 0.017 in men; OR: 1.129, 95% CI 1.046–1.219, P = 0.002 in women). In the stratified analysis, elevated TG was significantly associated with increased urinary albumin in subjects with eGFR ≥ 90 mL/min per 1.73 m², 5.6 ≤ FBG < 7.0 or 7.8 ≤ PBG < 11.1 mmol/L, 24 ≤ BMI < 28 kg/m², 120 ≤ SBP < 140 and/or 80 ≤ DBP < 90 mmHg.

Conclusions

We conclude that high TG levels rather than total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, or non-high-density lipoprotein cholesterol levels are associated with UACR in the general population in China.

Electronic supplementary material

The online version of this article (10.1186/s12933-019-0863-8) contains supplementary material, which is available to authorized users.

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.

Unmet Need for Adjunctive Dyslipidemia Therapy in Hypertriglyceridemia Management

Despite the important role of high-intensity statins in reducing atherosclerotic cardiovascular disease events in secondary and primary prevention, substantial residual risk persists, particularly among high-risk patients with type 2 diabetes mellitus, metabolic syndrome, and obesity. Considerable attention is currently directed to the role that elevated triglycerides (TGs) and non-high-density lipoprotein cholesterol levels play as important mediators of residual atherosclerotic cardiovascular disease risk, which is further strongly supported by genetic linkage studies. Previous trials with fibrates, niacin, and most cholesterol ester transfer protein inhibitors that targeted high-density lipoprotein cholesterol raising, and/or TG lowering, have failed to show conclusive evidence of incremental event reduction after low-density lipoprotein cholesterol levels were "optimally controlled" with statins. Although omega-3 fatty acids are efficacious in lowering TG levels and may have pleiotropic effects such as reducing plaque instability and proinflammatory mediators of atherogenesis, clinical outcomes data are currently lacking. Several ongoing randomized controlled trials of TG-lowering strategies with an optimal dosage of omega-3 fatty acids are nearing completion.

Elevated Levels of Very Low-density Lipoprotein Cholesterol Independently Associated with In-stent Restenosis in Diabetic Patients after Drug-eluting Stent Implantation

Background:

High rate of in-stent restenosis (ISR) remained an unsolved clinical problem in clinical practice, especially among patients with diabetes mellitus (DM). Diabetic patients often had hypertriglyceridemia with elevated levels of very low-density lipoprotein cholesterol (VLDL-C). Increasing evidence suggested that VLDL-C was known as a significant risk factor for atherosclerosis and had been recommended as a treatment target by current dyslipidemia guidelines. However, the role of VLDL-C in the occurrence and development of ISR in coronary artery disease (CAD) patients with DM had not been studied. The aim of this study was to evaluate the association between the elevated levels of VLDL-C and the risk of ISR in CAD patients with DM.

Methods:

A total of 1390 diabetic patients, who underwent coronary drug-eluting stent (DES) implantation at Beijing Anzhen Hospital and followed up by angiography within 6–24 months, were consecutively enrolled. Patients’ demographic and clinical characteristics, including age, gender, CAD risk factors, family history, life style, medical history, and coronary angiographic information, were collected carefully at baseline percutaneous coronary intervention and follow-up angiography. Multivariate Cox's proportional hazards regression modeling using the step-wise method (entry, 0.05; removal, 0.05) was used to determine the independent risk associated with ISR in diabetic patients.

Results:

Finally, 1206 of patients were included in this study. ISR occurred in 132/1206 diabetic patients (10.9%) by follow-up angiography. Patients with ISR had elevated median serum VLDL-C levels compared with those without ISR (0.65 mmol/L vs. 0.52 mmol/L, P = 0.030). The multivariate regression analysis showed that VLDL-C was significantly associated with the risk of ISR in diabetic CAD patients (hazard ratio [HR] = 1.15, 95% confidence interval [CI]: 1.03–1.29, P = 0.017). The HR for the risk of ISR associated with VLDL-C level ≥0.52 mmol/L was 3.01 (95% CI: 1.24–7.34, P = 0.015).

Conclusion:

The elevated level of serum VLDL-C was a significant and independent risk factor for ISR in diabetic CAD patients after coronary DES implantation.

Absence of ANGPTL4 in adipose tissue improves glucose tolerance and attenuates atherogenesis

Alterations in ectopic lipid deposition and circulating lipids are major risk factors for developing cardiometabolic diseases. Angiopoietin-like protein 4 (ANGPTL4), a protein that inhibits lipoprotein lipase (LPL), controls fatty acid (FA) uptake in adipose and oxidative tissues and regulates circulating triacylglycerol-rich (TAG-rich) lipoproteins. Unfortunately, global depletion of ANGPTL4 results in severe metabolic abnormalities, inflammation, and fibrosis when mice are fed a high-fat diet (HFD), limiting our understanding of the contribution of ANGPTL4 in metabolic disorders. Here, we demonstrate that genetic ablation of ANGPTL4 in adipose tissue (AT) results in enhanced LPL activity, rapid clearance of circulating TAGs, increased AT lipolysis and FA oxidation, and decreased FA synthesis in AT. Most importantly, we found that absence of ANGPTL4 in AT prevents excessive ectopic lipid deposition in the liver and muscle, reducing novel PKC (nPKC) membrane translocation and enhancing insulin signaling. As a result, we observed a remarkable improvement in glucose tolerance in short-term HFD-fed AT-specific Angptl4-KO mice. Finally, lack of ANGPTL4 in AT enhances the clearance of proatherogenic lipoproteins, attenuates inflammation, and reduces atherosclerosis. Together, these findings uncovered an essential role of AT ANGPTL4 in regulating peripheral lipid deposition, influencing whole-body lipid and glucose metabolism and the progression of atherosclerosis.

Genome-wide association study identifies a missense variant at APOA5 for coronary artery disease in Multi-Ethnic Cohorts from Southeast Asia

Recent genome-wide association studies (GWAS) have identified multiple loci associated with coronary artery disease (CAD) among predominantly Europeans. However, their relevance to multi-ethnic populations from Southeast Asia is largely unknown. We performed a meta-analysis of four GWAS comprising three Chinese studies and one Malay study (Total N = 2,169 CAD cases and 7,376 controls). Top hits (P < 5 × 10-8) were further evaluated in 291 CAD cases and 1,848 controls of Asian Indians. Using all datasets, we validated recently identified loci associated with CAD. The involvement of known canonical pathways in CAD was tested by Ingenuity Pathway Analysis. We identified a missense SNP (rs2075291, G > T, G185C) in APOA5 for CAD that reached robust genome-wide significance (Meta P = 7.09 × 10-10, OR = 1.636). Conditional probability analysis indicated that the association at rs2075291 was independent of previously reported index SNP rs964184 in APOA5. We further replicated 10 loci previously identified among predominantly Europeans (P: 1.33 × 10-7-0.047). Seven pathways (P: 1.10 × 10-5-0.019) were identified. We identified a missense SNP, rs2075291, in APOA5 associated with CAD at a genome-wide significance level and provided new insights into pathways contributing to the susceptibility to CAD in the multi-ethnic populations from Southeast Asia.

Residual Risk of Atherosclerotic Cardiovascular Events in Relation to Reductions in Very-Low-Density Lipoproteins

Background

It is uncertain whether pharmacological reductions in very‐low‐density lipoproteins (VLDLs), and their component triglyceride and cholesterol could reduce residual risk of atherosclerotic cardiovascular disease (ASCVD) events among individuals in whom low‐density lipoprotein cholesterol (LDL‐C) has been adequately lowered. We examined whether individuals with greater on‐statin reductions in VLDL‐related measures—beyond reductions in LDL‐C—were at further reduced risk of ASCVD.

Methods and Results

In 9423 participants in the JUPITER (Justification for the Use of Statins in Prevention) trial (NCT00239681), at baseline and on statin we measured standard lipids, 400‐MHz proton nuclear magnetic resonance spectroscopy‐measured VLDL particle subclasses (small, medium, and large VLDL lipoprotein particle concentration), and total VLDL cholesterol mass. Compared with individuals allocated to placebo, we examined risk of incident ASCVD (N=211) among statin‐allocated participants who achieved minimal (<median) or greater (≥median) marker reductions using adjusted Cox models. On‐statin changes in VLDL‐related markers were only modestly correlated (Spearman r≤0.29) with change in LDL‐C. On‐statin median LDL‐C was 54 mg/dL and triglyceride was 101 mg/dL. Dose‐response reductions in ASCVD risk were observed for greater reductions in LDL‐C, VLDL cholesterol mass, and small VLDL lipoprotein particle concentration; the latter 2 remained significant after incremental adjustment for change in LDL‐C (P≤0.006). Conversely, there was no further risk reduction with greater reductions in triglycerides or large/medium VLDL lipoprotein particle concentration.

Conclusions

Pharmacological reduction in small, cholesterol‐enriched, triglyceride‐depleted VLDL was associated with reduction in ASCVD risk. Chemically measured triglycerides may not sufficiently capture risk related to VLDL pathways. These findings also support broader profiling of lipid and lipoprotein changes in response to statins as prognostic markers of individual benefit, supporting more precision‐medicine, individualized approaches to cardiovascular risk reduction.

Clinical Trial Registration

URL: https://www.clinicaltrials.gov. Unique identifier: NCT00239681.

Current Consensus and Controversies in Guidelines for Lipid and Hypertension Management in Diabetes

Despite major advances, many patients with diabetes are currently achieving suboptimal control of lipids and blood pressure. The new cholesterol guidelines by the ACC/AHA have reignited the emphasis on more intensive treatment with statins in the population at high risk of CVD, including those with diabetes. While these guidelines do not include specific lipid goals, several other guidelines have retained previously defined risk-based LDL-C and non-HDL-C goals. More recent data indicate potential benefits in CVD outcomes with non-statin therapy added to statin therapy. On-going long-term trials with PCSK-9 inhibitors may help answer the question of the benefits and safety of very low LDL-C. Regarding the blood pressure guidelines, there remains an inconsistency of evidence for targets to reduce CVD outcomes. The ACCORD trial weighted heavily in the recent meta-analyses, leading to currently recommended goal of <140/90 mmHg. Studies targeting blood pressure goals of <130 mmHg in younger patients with diabetes, including sub-populations of interest, may help solve the controversy. Until we have these data, perhaps it is time to shift our focus from a rigid blood pressure target to risk-based goals.

Do triglyceride-lowering drugs decrease risk of cardiovascular disease?

PURPOSE OF REVIEW

This review summarizes the evidence supporting a relationship between lowering triglycerides (TGs) and TG-rich lipoprotein cholesterol (TGRL-C) levels and reduced atherosclerotic cardiovascular disease (ASCVD) event risk.

RECENT FINDINGS

Data from observational investigations, including studies of genetic variants, provide evidence consistent with a causal relationship between elevations in TG and TGRL-C and greater risk for ASCVD. Randomized controlled trial evidence of ASCVD risk reduction with therapies that substantially lower TG and TGRL-C is limited by the fact that no large-scale trial results have been published from a study that enrolled subjects selected specifically on the basis of TG or TGRL-C elevation, although three such trials are underway or in the planning stages. Subgroup analyses from randomized controlled trials are suggestive of a reduction in coronary heart disease and ASCVD event rates with statins, fibrates, omega-3 fatty acid concentrates, and niacin in subjects with elevated TGs, particularly if accompanied by low high-density lipoprotein-cholesterol. Mechanistic studies also support the biologic plausibility of this relationship.

SUMMARY

In conclusion, the available data are suggestive of a benefit of ASCVD reduction with therapies that lower TG and TGRL-C; results from ongoing outcomes trials are expected to provide definitive evidence of this relationship.

Hypertriglyceridaemia and risk of coronary artery disease

An elevated serum level of LDL cholesterol is a well-known risk factor for cardiovascular disease (CVD), but the role of elevated triglyceride levels is debated. Controversies regarding hypertriglyceridaemia as an independent risk factor for CVD have occurred partly because elevated triglyceride levels are often a component of atherogenic dyslipidaemia - they are associated with decreased levels of HDL cholesterol and increased levels of small dense LDL particles, which are highly atherogenic. Findings from several large studies indicate that elevated levels of triglycerides (either fasting or nonfasting) or, more specifically, triglyceride-rich lipoproteins and their remnants, are independently associated with increased risk of CVD. Possible mechanisms for this association include excessive free fatty acid release, production of proinflammatory cytokines, coagulation factors, and impairment of fibrinolysis. Therapeutic targeting of hypertriglyceridaemia could, therefore, reduce CVD and cardiovascular events, beyond the reduction achieved by LDL-cholesterol lowering. Elevated triglyceride levels are reduced with lifestyle interventions and fibrates, which can be combined with omega-3 fatty acids. Some new drugs are on the horizon, such as volanesorsen (which targets apolipoprotein C-III), pemafibrate, and others. However, CVD outcome studies with triglyceride-lowering agents have produced inconsistent results, meaning that no convincing evidence is available that lowering triglycerides by any approach can reduce mortality.

Lipoprotein lipase activity and interactions studied in human plasma by isothermal titration calorimetry

LPL hydrolyzes triglycerides in plasma lipoproteins. Due to the complex regulation mechanism, it has been difficult to mimic the physiological conditions under which LPL acts in vitro. We demonstrate that isothermal titration calorimetry (ITC), using human plasma as substrate, overcomes several limitations of previously used techniques. The high sensitivity of ITC allows continuous recording of the heat released during hydrolysis. Both initial rates and kinetics for complete hydrolysis of plasma lipids can be studied. The heat rate was shown to correspond to the release of fatty acids and was linearly related to the amount of added enzyme, either purified LPL or postheparin plasma. Addition of apoC-III reduced the initial rate of hydrolysis by LPL, but the inhibition became less prominent with time when the lipoproteins were triglyceride poor. Addition of angiopoietin-like protein (ANGPTL)3 or ANGPTL4 caused reduction of the activity of LPL via a two-step mechanism. We conclude that ITC can be used for quantitative measurements of LPL activity and interactions under in vivo-like conditions, for comparisons of the properties of plasma samples from patients and control subjects as substrates for LPL, as well as for testing of drug candidates developed with the aim to affect the LPL system.

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 remnant-like particle cholesterol from the MARINE and ANCHOR studies

BACKGROUND AND AIMS

Remnant-like particle cholesterol (RLP-C) is atherogenic and may increase atherosclerotic cardiovascular disease risk. Icosapent ethyl is a high-purity prescription eicosapentaenoic acid ethyl ester (approved as an adjunct to diet to reduce triglyceride [TG] levels in adult patients with TGs ≥500 mg/dL [≥5.65 mmol/L] at 4 g/day). In the MARINE and ANCHOR studies, icosapent ethyl reduced TG and other atherogenic lipid parameter levels without increasing low-density lipoprotein cholesterol (LDL-C) levels. This exploratory analysis evaluated the effects of icosapent ethyl on calculated and directly measured RLP-C.

METHODS

MARINE (TGs ≥500 and ≤2000 mg/dL [≥5.65 mmol/L and ≤22.6 mmol/L]) and ANCHOR (TGs ≥200 and <500 mg/dL [≥2.26 and <5.65 mmol/L] despite statin-controlled LDL-C) were phase 3, 12-week, double-blind studies that randomized adult patients to icosapent ethyl 4 g/day, 2 g/day, or placebo. This analysis assessed median percent change from baseline to study end in directly measured (immunoseparation assay) RLP-C levels (MARINE, n = 218; ANCHOR, n = 252) and calculated RLP-C levels in the full populations.

RESULTS

Icosapent ethyl 4 g/day significantly reduced directly measured RLP-C levels -29.8% (p = 0.004) in MARINE and -25.8% (p = 0.0001) in ANCHOR versus placebo, and also reduced directly measured RLP-C levels to a greater extent in subgroups with higher versus lower baseline TG levels, in patients receiving statins versus no statins (MARINE), and in patients receiving medium/higher-intensity versus lower-intensity statins (ANCHOR). Strong correlations were found between calculated and directly measured RLP-C for baseline, end-of-treatment, and percent change values in ANCHOR and MARINE (0.73-0.92; p < 0.0001 for all).

CONCLUSIONS

Icosapent ethyl 4 g/day significantly reduced calculated and directly measured RLP-C levels versus placebo in patients with elevated TG levels from the MARINE and ANCHOR studies.

Omega-3 Fatty Acid Formulations in Cardiovascular Disease: Dietary Supplements are Not Substitutes for Prescription Products

Omega-3 fatty acid products are available as prescription formulations (icosapent ethyl, omega-3-acid ethyl esters, omega-3-acid ethyl esters A, omega-3-carboxylic acids) and dietary supplements (predominantly fish oils). Most dietary supplements and all but one prescription formulation contain mixtures of the omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Products containing both EPA and DHA may raise low-density lipoprotein cholesterol (LDL-C). In clinical trials, the EPA-only prescription product, icosapent ethyl, did not raise LDL-C compared with placebo. To correct a common misconception, it is important to note that omega-3 fatty acid dietary supplements are not US FDA-approved over-the-counter drugs and are not required to demonstrate safety and efficacy prior to marketing. Conversely, prescription products are supported by extensive clinical safety and efficacy investigations required for FDA approval and have active and ongoing safety monitoring programs. While omega-3 fatty acid dietary supplements may have a place in the supplementation of diet, they generally contain lower levels of EPA and DHA than prescription products and are not approved or intended to treat disease. Perhaps due to the lack of regulation of dietary supplements, EPA and DHA levels may vary widely within and between brands, and products may also contain unwanted cholesterol or fats or potentially harmful components, including toxins and oxidized fatty acids. Accordingly, omega-3 fatty acid dietary supplements should not be substituted for prescription products. Similarly, prescription products containing DHA and EPA should not be substituted for the EPA-only prescription product, as DHA may raise LDL-C and thereby complicate the management of patients with dyslipidemia.

A genome-wide study of lipid response to fenofibrate in Caucasians: a combined analysis of the GOLDN and ACCORD studies

BACKGROUND

Fibrates are commonly prescribed for hypertriglyceridemia, but they also lower LDL cholesterol and increase HDL cholesterol. Large interindividual variations in lipid response suggest that some patients may benefit more than others and genetic studies could help identify such patients.

METHODS

We carried out the first genome-wide association study of lipid response to fenofibrate using data from two well-characterized clinical trials: the Genetics of Lipid Lowering Drugs and Diet Network (GOLDN) Study and the Action to Control Cardiovascular Risk in Diabetes (ACCORD) Study. Genome-wide association study data from both studies were imputed to the 1000 Genomes CEU reference panel (phase 1). Lipid response was modeled as the log ratio of the post-treatment lipid level to the pretreatment level. Linear mixed models (GOLDN, N=813 from 173 families) and linear regression models (ACCORD, N=781) adjusted for pretreatment lipid level, demographic variables, clinical covariates, and ancestry were used to evaluate the association of genetic markers with lipid response. Among Caucasians, the results were combined using inverse-variance weighted fixed-effects meta-analyses. The main findings from the meta-analyses were examined in other ethnic groups from the HyperTG study (N=267 Hispanics) and ACCORD (N=83 Hispanics, 138 African Americans).

RESULTS

A known lipid locus harboring the pre-B-cell leukemia homeobox 4 (PBX4) gene on chromosome 19 is important for LDL cholesterol response to fenofibrate (smallest P=1.5×10). The main results replicated with nominal statistical significance in Hispanics from ACCORD (P<0.05).

CONCLUSION

Future research should evaluate the usefulness of this locus to refine clinical strategies for lipid-lowering treatments.

Triglycerides and Triglyceride-Rich Lipoproteins in the Causal Pathway of Cardiovascular Disease

Epidemiologic and clinical studies suggest that elevated triglyceride levels are a biomarker of cardiovascular (CV) risk. Consistent with these findings, recent genetic evidence from mutational analyses, genome-wide association studies, and Mendelian randomization studies provide robust evidence that triglycerides and triglyceride-rich lipoproteins are in the causal pathway for atherosclerotic CV disease, indicating that they may play a pathogenic role, much like low-density lipoprotein cholesterol (LDL-C). Although statins are the cornerstone of dyslipidemia management, high triglyceride levels may persist in some patients despite statin therapy. Several triglyceride-lowering agents are available, including fibrates, niacin, and omega-3 fatty acids, of which prescription omega-3 fatty acids have the best tolerability and safety profile. In clinical studies, omega-3 fatty acids have been shown to reduce triglyceride levels, but products containing both eicosapentaenoic acid and docosahexaenoic acid may increase LDL-C levels. Icosapent ethyl, a high-purity eicosapentaenoic acid-only product, does not raise LDL-C levels and also reduces triglyceride, non-high-density lipoprotein cholesterol, and triglyceride-rich lipoprotein levels. In conclusion, omega-3 fatty acids are currently being evaluated in large CV outcome studies in statin-treated patients; these studies should help to elucidate the causative role of triglycerides in atherosclerotic CV disease.

From Loci to Biology: Functional Genomics of Genome-Wide Association for Coronary Disease

Genome-wide association studies have provided a rich collection of ≈ 58 coronary artery disease (CAD) loci that suggest the existence of previously unsuspected new biology relevant to atherosclerosis. However, these studies only identify genomic loci associated with CAD, and many questions remain even after a genomic locus is definitively implicated, including the nature of the causal variant(s) and the causal gene(s), as well as the directionality of effect. There are several tools that can be used for investigation of the functional genomics of these loci, and progress has been made on a limited number of novel CAD loci. New biology regarding atherosclerosis and CAD will be learned through the functional genomics of these loci, and the hope is that at least some of these new pathways relevant to CAD pathogenesis will yield new therapeutic targets for the prevention and treatment of CAD.

From Lipids to Inflammation: New Approaches to Reducing Atherosclerotic Risk

The introduction of statins ≈ 30 years ago ushered in the era of lipid lowering as the most effective way to reduce risk of atherosclerotic cardiovascular disease. Nonetheless, residual risk remains high, and statin intolerance is frequently encountered in clinical practice. After a long dry period, the field of therapeutics targeted to lipids and atherosclerosis has entered a renaissance. Moreover, the demonstration of clinical benefits from the addition of ezetimibe to statin therapy in subjects with acute coronary syndromes has renewed the enthusiasm for the cholesterol hypothesis and the hope that additional agents that lower low-density lipoprotein will decrease risk of atherosclerotic cardiovascular disease. Drugs in the orphan disease category are now available for patients with the most extreme hypercholesterolemia. Furthermore, discovery and rapid translation of a novel biological pathway has given rise to a new class of cholesterol-lowering drugs, the proprotein convertase subtilisin kexin-9 inhibitors. Trials of niacin added to statin have failed to demonstrate cardiac benefits, and 3 cholesterol ester transfer protein inhibitors have also failed to reduce atherosclerotic cardiovascular disease risk, despite producing substantial increases in HDL levels. Although the utility of triglyceride-lowering therapies remains uncertain, 2 large clinical trials are testing the influence of omega-3 polyunsaturated fatty acids on atherosclerotic events in hypertriglyceridemia. Novel antisense therapies targeting apolipoprotein C-III (for triglyceride reduction) and apo(a) (for lipoprotein(a) reduction) are showing a promising trajectory. Finally, 2 large clinical trials are formally putting the inflammatory hypothesis of atherosclerosis to the test and may open a new avenue for cardiovascular disease risk reduction.

Role of lipoprotein lipase in lipid metabolism

PURPOSE OF REVIEW

A major step in energy metabolism is hydrolysis of triacylglycerol-rich lipoproteins (TRLs) to release fatty acids that can be used or stored. This is accomplished by lipoprotein lipase (LPL) at 'binding lipolysis sites' at the vascular endothelium. A multitude of interactions are involved in this seemingly simple reaction. Recent advances in the understanding of some of these factors will be discussed in an attempt to build a comprehensive picture.

RECENT FINDINGS

The first event in catabolism of TRLs is that they dock at the vascular endothelium. This requires LPL and GPIHBP1, the endothelial transporter of LPL.Kinetic studies in rats with labeled chylomicrons showed that once a chylomicron has docked in the heart it stays for minutes and a large number of triacylglycerol molecules are split. The distribution of binding between tissues reflects the amount of LPL, as evident from studies with mutant mice.Clearance of TRLs is often slowed down in metabolic disease, as was demonstrated both in mice and men. In mice, this was directly connected to decreased amounts of endothelial LPL.

SUMMARY

The LPL system is central in energy metabolism and results from interplay between several factors. Rapid and exciting progress is being made.

JCL roundtable: Lessons from genetic variants altering lipoprotein metabolism

Because the Human Genome Project reached its first major milestone in completing the full sequence of human DNA, many new discoveries have been made relating genetic variants to disease. The new methodology that allows much more rapid and focused analyses of selected genes and the ability to screen the entire exome of any individual has provided tools to examine literally thousands of individuals for a given study. Genetic analysis has become a large-scale epidemiologic tool for examining variants in gene structure and correlating them with phenotypic markers of human disorders. These genome-wide association studies have been quite revealing about the mechanism of disorders of many types. These tools have been applied to the appearance of clinical atherosclerosis and to the chronic metabolic risk factors for this disease process. We are joined by 2 individuals who have made very significant contributions to this area of research: Dr Brian Ference of Wayne State University School of Medicine and Dr Sekar Kathiresan from Massachusetts General Hospital and Harvard Medical School. In our discussion, we are going to focus on genetic variants, which lead to changes in lipoprotein concentrations and those that have an association with earlier onset of clinical vascular disease. This roundtable was recorded during the November 2016 American Heart Association Scientific Sessions in Orlando, Florida.

Postprandial lipids accelerate and redirect nitric oxide consumption in plasma

Nitric oxide (NO) and O2 are both three-to four-fold more soluble in biological lipids than in aqueous solutions. Their higher concentration within plasma lipids accelerates NO autoxidation to an extent that may be of importance to overall NO bioactivity. This study was undertaken to test the hypothesis that increased plasma lipids after a high-fat meal appreciably accelerate NO metabolism and alter the byproducts formed. We found that plasma collected from subjects after consumption of a single high-fat meal had a higher capacity for NO consumption and consumed NO more rapidly compared to fasting plasma. This increased NO consumption showed a direct correlation with plasma triglyceride concentrations (p = 0.006). The accelerated NO consumption in postprandial plasma was reversed by removal of the lipids from the plasma, was mimicked by the addition of hydrophobic micelles to aqueous buffer, and could not be explained by the presence of either free hemoglobin or ceruloplasmin. The products of NO consumption were shifted in postprandial plasma, with 55% more nitrite (n = 12, p = 0.002) but 50% less SNO (n = 12, p = 0.03) production compared to matched fasted plasma. Modeling calculations indicated that NO autoxidation was accelerated by about 48-fold in the presence of plasma lipids. We conclude that postprandial triglyceride-rich lipoproteins exert a significant influence on NO metabolism in plasma.

Hypertriglyceridemia and Cardiovascular Diseases: Revisited

Residual cardiovascular risk and failure of high density lipoprotein cholesterol raising treatment have refocused interest on targeting hypertriglyceridemia. Hypertriglyceridemia, triglyceride-rich lipoproteins, and remnant cholesterol have demonstrated to be important risk factors for cardiovascular disease; this has been demonstrated in experimental, genetic, and epidemiological studies. Fibrates can reduce cardiovascular event rates with or without statins. High dose omega-3 fatty acids continue to be evaluated and new specialized targeting treatment modulating triglyceride pathways, such as inhibition of apolipoprotein C-III and angiopoietin-like proteins, are being tested with regard to their effects on lipid profiles and cardiovascular outcomes. In this review, we will discuss the role of hypertriglyceridemia, triglyceride-rich lipoproteins and remnant cholesterol on cardiovascular disease, and the potential implications for treatment stargeting hypertriglyceridemia.

Effects of K-877, a novel selective PPARα modulator (SPPARMα), in dyslipidaemic patients: A randomized, double blind, active- and placebo-controlled, phase 2 trial

BACKGROUND AND AIMS

To assess the efficacy and safety of K-877 (Pemafibrate), a novel selective peroxisome proliferator-activated receptor α modulator (SPPARMα) that possesses unique PPARα activity and selectivity, compared with placebo and fenofibrate in dyslipidaemic patients with high triglyceride (TG) and low high-density lipoprotein cholesterol (HDL-C) levels.

METHODS AND RESULTS

This study was a double blind, placebo-controlled, parallel-group 12-week clinical trial. The study randomized 224 patients to K-877 0.025, 0.05, 0.1, 0.2 mg BID, fenofibrate 100 mg QD, or placebo (1:1:1:1:1:1) groups. Least squares mean percent changes from the baseline TG levels were -30.9%, -36.4%, -42.6%, -42.7% for the K-877 0.025, 0.05, 0.1, 0.2 mg BID respectively (p < 0.001), which were greater than that of the fenofibrate 100 mg QD (-29.7%, p < 0.001) group. Statistically significant improvements from the baseline HDL-C, very-low-density lipoprotein cholesterol, chylomicron cholesterol, remnant lipoprotein cholesterol, apolipoprotein (apo) B (apoB), and apoC-III were also observed in the K-877 groups. The incidence of adverse events (AEs) in the K-877 groups (32.4-56.8%) was comparable to those in placebo (47.2%) and fenofibrate 100 mg QD (56.8%); adverse drug reactions (ADRs) in the K-877 groups (2.7-5.4%) were less than those in placebo (8.3%) and fenofibrate 100 mg QD (10.8%) groups.

CONCLUSION

In dyslipidaemic patients with high TG and low HDL-C, K-877 improved TG, HDL-C, and other lipid parameters without increasing AEs or ADRs, compared to placebo and fenofibrate. K-877 can be expected to improve atherogenicity and to be a new beneficial treatment for dyslipidaemic patients.

Apolipoprotein A5 and apolipoprotein C3 single nucleotide polymorphisms are correlated with an increased risk of coronary heart disease: a case-control and meta-analysis study

Background

Triglycerides (TGs) are proatherogenic lipoproteins involving the risk of coronary heart disease (CHD), while apolipoprotein A5 (APOA5) and apolipoprotein C3 (APOC3) are main lipoproteins composing TG-rich lipoproteins. In this study, we aim to explore the correlation of CHD with APOA5 -1131 T > C and APOC3 -455 T > C single nucleotide polymorphisms (SNPs).

Methods

A sum of 210 CHD patients, hospitalized between Jan. 2013 and Mar. 2015 at China-Japan Union Hospital, Jilin University, were selected as our case group and 223 healthy individuals who had physical examination at same hospital at the same period were selected as control group. The frequency distribution of genotypes of APOA5 -1131 T > C and APOC3 -455 T > C SNPs were measured by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). The Stata 12.0 software was utilized for statistical analyses.

Results

There was no significant difference on age and sex between case and control group (P > 0.05). History of smoking, drinking, hypertension and diabetes mellitus, body mass index and levels of TG and fasting blood sugar in case group were shown to be higher than control group (P < 0.05), while levels of total cholesterol, high-density lipoprotein cholesterol and low-density lipoprotein cholesterol in case group were lower than control group (P < 0.05). Both CC and TC′ + CC frequencies of APOA5 -1131 T > C and APOC3 -455 T > C in case group were higher compared to control group (both P < 0.05). Additionally, T allele frequencies of the two SNPs in case group were lower than control group, while C allele in case group has higher frequencies compared to control group (both P < 0.05). The results of meta-analysis under allele and dominant models showed that APOA5 -1131 T > C and APOC3 -455 T > C SNPs are likely to increase the risk of CHD (both P < 0.05).

Conclusion

APOA5 -1131 T > C and APOC3 -455 T > C SNPs may play potent roles in the development and progression of CHD.