Reduction of mortality in the Stockholm Ischaemic Heart Disease Secondary Prevention Study by combined treatment with clofibrate and nicotinic acid

Grape Seed Proanthocyanidin Extract Attenuates Cafeteria-Diet-Induced Liver Metabolic Disturbances in Rats: Influence of Photoperiod

This study investigated the influence of photoperiod (day length) on the efficacy of grape seed proanthocyanidin extract (GSPE) in mitigating metabolic disorders in obese rats fed a cafeteria diet. Rats were exposed to standard (L12), long (L18), or short (L6) photoperiods and treated with GSPE or vehicle. In the standard photoperiod, GSPE reduced body weight gain (50.5%), total cholesterol (37%), and triglycerides (34.8%), while increasing the expression of hepatic metabolic genes. In the long photoperiod, GSPE tended to decrease body weight gain, increased testosterone levels (68.3%), decreased liver weight (12.4%), and decreased reverse serum amino acids. In the short photoperiod, GSPE reduced glycemia (~10%) and lowered triglyceride levels (38.5%), with effects modified by diet. The standard photoperiod showed the greatest efficacy against metabolic syndrome-associated diseases. The study showed how day length affects GSPE's benefits and underscores considering biological rhythms in metabolic disease therapies.

Lipoproteins, Cholesterol, and Atherosclerotic Cardiovascular Disease in East Asians and Europeans

One fifth of the world population live in East Asia comprising Japan, Korea, and China where ischemic heart disease, a major component of atherosclerotic cardiovascular disease (ASCVD), is the second most frequent cause of death. Each of low-density lipoproteins (LDL), remnant lipoproteins, and lipoprotein(a), summarized as non-high-density lipoproteins (non-HDL) or apolipoprotein B (apoB) containing lipoproteins, causes ASCVD. However, a significant proportion of the evidence on lipoproteins and lipoprotein cholesterol with risk of ASCVD came from White people mainly living in Europe and North America and not from people living in East Asia or of East Asian descent. With a unique biological, geohistorical, and social background in this world region, East Asians have distinctive characteristics that might have potential impact on the association of lipoproteins and lipoprotein cholesterol with risk of ASCVD. Considering the movement across national borders in the World, understanding of lipoprotein and lipoprotein cholesterol evidence on ASCVD in East Asia is important for both East Asian and non-East Asian populations wherever they live in the World.In this review, we introduce the biological features of lipoproteins and lipoprotein cholesterol and the evidence for their association with risk of ASCVD in East Asian and European populations. We also provide an overview of guideline recommendations for prevention of ASCVD in these two different world regions. Finally, specific preventive strategies and future perspectives are touched upon.

The role of dietary antioxidants in type 2 diabetes and neurodegenerative disorders: An assessment of the benefit profile

Healthy diet is vital to cellular health. The human body succumbs to numerous diseases which afflict severe economic and psychological burdens on the patient and family. Oxidative stress is a possible crucial regulator of various pathologies, including type 2 diabetes and neurodegenerative diseases. It generates reactive oxygen species (ROS) that trigger the dysregulation of essential cellular functions, ultimately affecting cellular health and homeostasis. However, lower levels of ROS can be advantageous and are implicated in a variety of signaling pathways. Due to this dichotomy, the terms oxidative "eustress," which refers to a good oxidative event, and "distress," which can be hazardous, have developed. ROS affects multiple signaling pathways, leading to compromised insulin secretion, insulin resistance, and β-cell dysfunction in diabetes. ROS is also associated with increased mitochondrial dysfunction and neuroinflammation, aggravating neurodegenerative conditions in the body, particularly with age. Treatment includes drugs/therapies often associated with dependence, side effects including non-selectivity, and possible toxicity, particularly in the long run. It is imperative to explore alternative medicines as an adjunct therapy, utilizing natural remedies/resources to avoid all the possible harms. Antioxidants are vital components of our body that fight disease by reducing oxidative stress or nullifying the excess toxic free radicals produced under various pathological conditions. In this review, we focus on the antioxidant effects of components of dietary foods such as tea, coffee, wine, oils, and honey and the role and mechanism of action of these antioxidants in alleviating type 2 diabetes and neurodegenerative disorders. We aim to provide information about possible alternatives to drug treatments used alone or combined to reduce drug intake and encourage the consumption of natural ingredients at doses adequate to promote health and combat pathologies while reducing unwanted risks and side effects.

Comparison of the effects of triglyceride variability and exposure estimate on clinical prognosis in diabetic patients

BACKGROUND

Hypertriglyceridemia is an important feature of dyslipidemia in type 1 and type 2 diabetic patients and associated with the development of atherosclerotic cardiovascular disease. Recently, variability of lipid profile has been suggested as a residual risk factor for cardiovascular disease. This study compared the clinical impact of serum triglyceride variability, and their cumulative exposure estimates on cardiovascular prognosis in diabetic patients.

METHODS

A total of 25,933 diabetic patients who had serum triglyceride levels measured at least 3 times and did not have underlying malignancy, myocardial infarction (MI), and stroke during the initial 3 years (modeling phase) were selected from three tertiary hospitals. They were divided into a high/low group depending on their coefficient of variation (CV) and cumulative exposure estimate (CEE). Incidence of major adverse event (MAE), a composite of all-cause death, MI, and stroke during the following 5 years were compared between groups by multivariable analysis after propensity score matching.

RESULTS

Although there was a slight difference, both the high CV group and the high CEE group had a higher cardiovascular risk profile including male-dominance, smoking, alcohol, dyslipidemia, and chronic kidney disease compared to the low groups. After the propensity score matching, the high CV group showed higher MAE incidence compared to the low CV group (9.1% vs 7.7%, p = 0.01). In contrast, there was no significant difference of MAE incidence between the high CEE group and the low CEE group (8.6% vs 9.1%, p = 0.44). After the multivariable analysis with further adjustment for potential residual confounding factors, the high CV was suggested as an independent risk predictor for MAE (HR 1.19 [95% CI 1.03-1.37]).

CONCLUSION

Visit-to-visit variability of triglyceride rather than their cumulative exposure is more strongly related to the incidence of MAE in diabetic patients.

Comparative efficacy of pharmacological agents on reducing the risk of major adverse cardiovascular events in the hypertriglyceridemia population: a network meta-analysis

BACKGROUND

Hypertriglyceridemia (HTG) is considered an independent risk factor for major adverse cardiovascular events (MACE).

METHODS

This study analyzed the effects of various agents on MACE risk reduction in HTG (serum triglyceride ≥ 150 mg/dl) populations by performing a network meta-analysis. We performed a frequentist network meta-analysis to conduct direct and indirect comparisons of interventions. PubMed, EMBASE, and the Cochrane library were searched for trials until Jul 6, 2020. Randomized controlled trials that reported MACE associated with agents in entire HTG populations or in subgroups were included. The primary outcome was MACE.

RESULTS

Of the 2005 articles screened, 21 trials including 56,471 patients were included in the analysis. The network meta-analysis results for MACE risk based on frequency data showed that eicosapentaenoic acid (EPA) (OR: 1.32; 95% CI 1.19-1.46), gemfibrozil (OR: 1.53; 95% CI 1.20-1.95), niacin plus clofibrate (OR: 2.00; 95% CI 1.23-3.25), pravastatin (OR: 1.32; 95% CI 1.15-1.52), simvastatin (OR: 2.38; 95% CI 1.55-3.66), and atorvastatin (OR: 0.55; 95% CI 0.37-0.82) significantly reduced the risk of MACE compared to the control conditions. In the subgroup analysis of HTG patients with triglycerides ≥ 200 mg/dL, bezafibrate (OR: 0.56; 95% CI 0.33-0.94), EPA (OR: 0.72; 95% CI 0.62-0.82), and pravastatin (OR: 1.33; 95% CI 1.01-1.75) significantly reduced the MACE risk.

CONCLUSIONS

Simvastatin had a clear advantage in reducing the risk of MACE in the entire HTG population analyzed in this meta-analysis. EPA, but not omega-3 fatty acid, was considered an effective HTG intervention. Among fibrates, gemfibrozil was most effective, though bezafibrate may significantly reduce the risk of MACE in populations with triglyceride levels of 200-300 mg/dL. Trial registration retrospectively registered in PROSPERO (CRD42020213705).

NAD+ Metabolism as an Emerging Therapeutic Target for Cardiovascular Diseases Associated With Sudden Cardiac Death

In addition to its central role in mediating oxidation reduction in fuel metabolism and bioenergetics, nicotinamide adenine dinucleotide (NAD+) has emerged as a vital co-substrate for a number of proteins involved in diverse cellular processes, including sirtuins, poly(ADP-ribose) polymerases and cyclic ADP-ribose synthetases. The connection with aging and age-associated diseases has led to a new wave of research in the cardiovascular field. Here, we review the basics of NAD+ homeostasis, the molecular physiology and new advances in ischemic-reperfusion injury, heart failure, and arrhythmias, all of which are associated with increased risks for sudden cardiac death. Finally, we summarize the progress of NAD+-boosting therapy in human cardiovascular diseases and the challenges for future studies.

Contribution of remnant cholesterol to cardiovascular risk

BACKGROUND

Remnant cholesterol in triglyceride-rich lipoproteins is associated observationally and genetic, causally with increased risk of atherosclerotic cardiovascular disease in healthy individuals.

OBJECTIVES

We tested the hypothesis that an unmet medical need exists in individuals with high nonfasting remnant cholesterol and prior atherosclerotic cardiovascular disease.

METHODS

From amongst 109 574 individuals in a prospective cohort study of the Danish general population, we included 2973 individuals aged 20-80 with baseline diagnoses of myocardial infarction/ischaemic stroke ascertained from national Danish health registries.

RESULTS

The recurrent major cardiovascular event (MACE) incidence rates per 1000 person-years were 39 (95% confidence interval: 30-50) for individuals with remnant cholesterol levels ≥ 1.5 mmol L^-1 (≥58 mg dL^-1 ), 31 (26-37) for 1-1.49 mmol L^-1 (39-57 mg dL^-1 ), 27 (24-31) for 0.5-0.99 mmol L^-1 (19-38 mg dL^-1 ) and 23 (19-27) for individuals with remnant cholesterol < 0.5 mmol L^-1 (<19 mg dL^-1 ). Compared to individuals with remnant cholesterol < 0.5 mmol L^-1 (<19 mg dL^-1 ), the subhazard ratio for recurrent MACE was 1.23 (95% CI: 0.98-1.55) for individuals with remnant cholesterol levels of 0.5-0.99 mmol L^-1 (19-38 mg dL^-1 ), 1.48 (1.14-1.92) for 1-1.49 mmol L^-1 (39-57 mg dL^-1 ) and 1.79 (1.28-2.49) for ≥ 1.5 mmol L^-1 (≥58 mg dL^-1 ). The recurrent MACE incidence rates per 1000 person-years for individuals with remnant cholesterol levels < 0.5 mmol L^-1 (<19 mg dL^-1 ) and ≥ 1.5 mmol L^-1 (≥58 mg dL^-1 ) were 10 (6.6-15) and 31 (21-47) for those below age 65 and correspondingly 25 (21-30) and 43 (32-59) for those with LDL cholesterol levels < 3 mmol L^-1 (<116 mg dL^-1 ), respectively. For a 20% recurrent MACE risk reduction in secondary prevention, an estimated remnant cholesterol lowering of 0.83 mmol L^-1 (32 mg dL^-1 ) would be needed.

CONCLUSIONS

In individuals with a diagnosis of myocardial infarction/ischaemic stroke, a lower remnant cholesterol of 0.8 mmol L^-1 (32 mg dL^-1 ) was estimated to reduce recurrent MACE by 20% in secondary prevention. Our data indicate an unmet medical need for secondary prevention in individuals with high nonfasting remnant cholesterol levels.

Postprandial Hypertriglyceridaemia Revisited in the Era of Non-Fasting Lipid Profile Testing: A 2019 Expert Panel Statement, Main Text

Residual vascular risk exists despite the aggressive lowering of Low-Density Lipoprotein Cholesterol (LDL-C). A contributor to this residual risk may be elevated fasting, or non-fasting, levels of Triglyceride (TG)-rich lipoproteins. Therefore, there is a need to establish whethe a standardised Oral Fat Tolerance Test (OFTT) can improve atherosclerotic Cardiovascular (CV) Disease (ASCVD) risk prediction in addition to a fasting or non-fasting lipid profile. An expert panel considered the role of postprandial hypertriglyceridaemia (as represented by an OFTT) in predicting ASCVD. The panel updated its 2011 statement by considering new studies and various patient categories. The recommendations are based on expert opinion since no strict endpoint trials have been performed. Individuals with fasting TG concentration <1 mmol/L (89 mg/dL) commonly do not have an abnormal response to an OFTT. In contrast, those with fasting TG concentration ≥2 mmol/L (175 mg/dL) or nonfasting ≥2.3 mmol/L (200 mg/dL) will usually have an abnormal response. We recommend considering postprandial hypertriglyceridaemia testing when fasting TG concentrations and non-fasting TG concentrations are 1-2 mmol/L (89-175 mg/dL) and 1.3-2.3 mmol/L (115-200 mg/dL), respectively as an additional investigation for metabolic risk prediction along with other risk factors (obesity, current tobacco abuse, metabolic syndrome, hypertension, and diabetes mellitus). The panel proposes that an abnormal TG response to an OFTT (consisting of 75 g fat, 25 g carbohydrate and 10 g proteins) is >2.5 mmol/L (220 mg/dL). Postprandial hypertriglyceridaemia is an emerging factor that may contribute to residual CV risk. This possibility requires further research. A standardised OFTT will allow comparisons between investigational studies. We acknowledge that the OFTT will be mainly used for research to further clarify the role of TG in relation to CV risk. For routine practice, there is a considerable support for the use of a single non-fasting sample.

Effects of intermittent fasting and energy-restricted diets on lipid profile: A systematic review and meta-analysis

OBJECTIVES

To the best of our knowledge, no systematic review and meta-analysis has evaluated the cholesterol-lowering effects of intermittent fasting (IF) and energy-restricted diets (ERD) compared with control groups. The aim of this review and meta-analysis was to summarize the effects of controlled clinical trials examining the influence of IF and ERD on lipid profiles.

METHODS

A systematic review of four independent databases (PubMed/Medline, Scopus, Web of Science and Google Scholar) was performed to identify clinical trials reporting the effects of IF or ERD, relative to non-diet controls, on lipid profiles in humans. A random-effects model, employing the method of DerSimonian and Laird, was used to evaluate effect sizes, and results were expressed as weighted mean difference (WMD) and 95% confidence intervals (CIs). Heterogeneity between studies was calculated using Higgins I², with values ≥50% considered to represent high heterogeneity. Subgroup analyses were performed to examine the influence of intervention type, baseline lipid concentrations, degree of energy deficit, sex, health status, and intervention duration.

RESULTS

For the outcomes of low-density lipoprotein cholesterol (LDL-C), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), and triacylglycerols (TG), there were 34, 33, 35, and 33 studies meeting all inclusion criteria, respectively. Overall, results from the random-effects model indicated that IF and ERD interventions resulted significant changes in TC (WMD, -6.93 mg/dL; 95% CI, -10.18 to -3.67; P < 0.001; I² = 78.2%), LDL-C (WMD, -6.16 mg/dL; 95% CI, -8.42 to -3.90; P ˂ 0.001; I² = 52%), and TG concentrations (WMD, -6.46 mg/dL; 95% CI, -10.64 to -2.27; P = 0.002; I² = 61%). HDL-C concentrations did not change significantly after IF or ERD (WMD, 0.50 mg/dL; 95% CI, -0.69 to 1.70; P = 0.411; I² = 80%). Subgroup analyses indicated potentially differential effects between subgroups for one or more lipid parameters in the majority of analyses.

CONCLUSIONS

Relative to a non-diet control, IF and ERD are effective for the improvement of circulating TC, LDL-C, and TG concentrations, but have no meaningful effects on HDL-C concentration. These effects are influenced by several factors that may inform clinical practice and future research. The present results suggest that these dietary practices are a means of enhancing the lipid profile in humans.

Is hypertriglyceridemia atherogenic?

PURPOSE OF REVIEW

Hypertriglyceridemia occurs mainly because of metabolic disorders secondary to diabetes, alcohol intake, and/or overweight. Genetic factors have also been clearly identified in most severe cases. Triglycerides are generally considered as 'bystanders' for cardiovascular diseases. However, biological and basic research provides strong data suggesting that triglyceride-rich lipoproteins could be involved in the pathophysiology of cardiovascular diseases.

RECENT FINDINGS

The REDUCE-IT trial recently showed that icosapent ethyl reduces major cardiovascular events and related death.

SUMMARY

For many years, low-density lipoproteins (LDLs) have been considered the Holy Grail for atherosclerotic cardiovascular disease management. New data from basic research in biology, epidemiology, genetics, and preliminary clinical trials support the hypothesis that triglyceride-rich lipoproteins could be the causal factors for atherosclerotic cardiovascular disease; hence, triglyceride should be taken into consideration in the management of these patients. Omega-3-fatty acids used in the REDUCE-IT trial reduced the residual cardiovascular risk efficiently beyond statins. However, its effect has to be completely understood as it seems to be unrelated to LDLc or triglyceride reduction, but linked to pleiotropic effects involving inflammation, platelet adhesion, and plaque instability reduction, paving the way for trials that will target more specific potential pathophysiologic pathways.

Assessment of the Role of Niacin in Managing Cardiovascular Disease Outcomes: A Systematic Review and Meta-analysis

IMPORTANCE

Niacin remains a therapeutic option for patients with cardiovascular disease, but recent studies have called into question the effectiveness of other drugs that increase high-density lipoprotein cholesterol levels.

OBJECTIVE

To systematically review and evaluate the evidence supporting current US Food and Drug Administration-approved uses of niacin in cardiovascular disease prevention settings.

DATA SOURCES

MEDLINE, Embase, Cochrane Controlled Clinical Trial Register (Central), ClinicalTrials.gov, and TrialResults-center, from database inception to October 2017.

STUDY SELECTION

The systematic review included clinical trials involving niacin as a treatment for cardiovascular disease. The meta-analysis included randomized clinical trials reporting niacin's effect, as exposure, on at least 1 long-term cardiovascular disease outcome.

DATA EXTRACTION AND SYNTHESIS

Aggregate study-level data were extracted between November 2017 and January 2018 by 3 independent reviewers, and the analysis was performed in February 2018. Inverse-variance weighted methods were used to produce pooled risk ratios using random-effects models for between-study heterogeneity. Random effects-weighted metaregression analysis was used to assess the association of change in high-density lipoprotein cholesterol levels with the log risk ratio of the pooled results.

MAIN OUTCOMES AND MEASURES

Cardiovascular disease, coronary heart disease mortality, and other cardiovascular events, including acute coronary syndrome, fatal and nonfatal stroke, revascularization, and major adverse cardiac events.

RESULTS

Of 119 clinical trials, 17 documented niacin's effect on at least 1 cardiovascular disease outcome. The meta-analysis included 35 760 patients with histories of cardiovascular disease or dyslipidemia. Cumulative evidence found no preventive association of niacin with cardiovascular outcomes in secondary prevention. Stratified meta-analysis showed an association of niacin monotherapy with reduction of some cardiovascular events among patients without statin treatment (acute coronary syndrome: relative risk, 0.74; 95% CI, 0.58-0.96; stroke: relative risk, 0.74; 95% CI, 0.59-0.94; revascularization: relative risk, 0.51; 95% CI, 0.37-0.72). These results were mainly derived from 2 trials conducted in the 1970s and 1980s.

CONCLUSIONS AND RELEVANCE

Niacin may have some use in lipid control for secondary prevention as monotherapy, perhaps in patients intolerant to statins, but evidence is from older studies on a population potentially not representative of current-day patients.

The Origins and Early Evolution of Epidemiologic Research in Cardiovascular Diseases: A Tabular Record of Cohort and Case-Control Studies and Preventive Trials Initiated From 1946 to 1976

This article serves as a ready reference guide to the pioneering formal studies in cardiovascular disease (CVD) epidemiology initiated during 3 decades of the subject's evolution into an established academic field that contributed to the public health. The article is not intended to be a history of CVD epidemiology or an editorial about its significance. The appended tables include the titles and starting dates of the early studies, the names of their principal investigators, and references to a single defining article from each. The early observational studies of CVD epidemiology provided a widely useful CVD risk-factor paradigm. The early clinical trials justified the more definitive preventive trials of the 1980s and beyond. This early research in populations, along with others in clinics and laboratories, led to greater understanding of the causes of CVD, to a vigorous practice of preventive cardiology, and to national policy and programs of health promotion, all of which were coincident with a 50-year decline in CVD mortality rates.

Effects of high-density lipoprotein targeting treatments on cardiovascular outcomes: A systematic review and meta-analysis

BACKGROUND

The effects of increasing high-density lipoprotein cholesterol on cardiovascular outcomes remain uncertain.

DESIGN

We conducted a meta-analysis to investigate the effects of high-density lipoprotein cholesterol modifiers (niacin, fibrates and cholesteryl ester transfer protein inhibitors) on cardiovascular outcomes.

METHODS

Thirty-one randomized controlled trials (154,601 patients) with a follow-up of 6 months or more and a sample size of 100 or more patients were selected using MEDLINE, EMBASE and CENTRAL database (inception January 2018).

RESULTS

High-density lipoprotein cholesterol modifiers had no statistically significant effect on cardiovascular mortality in terms of relative risk (RR) (RR 0.94, 95% confidence interval (CI) 0.89-1.00, P = 0.05, I² = 13%) or absolute risk (risk difference -0.0001, 95% CI -0.0014, 0.0011, P = 0.84, I² = 28%). High-density lipoprotein cholesterol modifiers reduced the RR of myocardial infarction (RR 0.87, 95% CI 0.82-0.93, P < 0.001, I² = 37%). This significant effect was derived by the use of fibrates (RR 0.80, 95% CI 0.73-0.87, P < 0.001, I² = 22%) and meta-regression analysis showed that this benefit was consistent with an absolute reduction in low-density lipoprotein cholesterol. High-density lipoprotein cholesterol modifiers had no effect on stroke (RR 1.00, 95% CI 0.93-1.09, P = 0.94, I² = 25%) or all-cause mortality (RR 1.02, 95% CI 0.97-1.08, P = 0.48, I² = 49%). Meta-regression analyses failed to demonstrate a significant association of pharmacologically increased high-density lipoprotein cholesterol with key endpoints. In studies with background statin therapy, high-density lipoprotein cholesterol modifiers had no statistically significant impact on cardiovascular mortality, myocardial infarction, stroke or all-cause mortality ( P > 0.05).

CONCLUSION

The use of high-density lipoprotein cholesterol modifying treatments had no significant effect on cardiovascular mortality, stroke or all-cause mortality. The beneficial effect on myocardial infarction was lost when drugs were used with statin therapy.

Role of niacin in current clinical practice

Despite significant risk reduction with statin therapy, there remains a residual cardiovascular risk. It has been seen that aggressive statin therapy in high risk patients may not lower the low-density lipoprotein cholesterol to goal in up to 40% of patients. Niacin is a potent high-density lipoprotein cholesterol-raising drug, and has been proposed as an attractive approach to reduce cardiac events in patients with or at risk of atherosclerotic cardiovascular disease. However, previous evidence for niacin has been challenged by negative outcomes in two large, randomized, controlled trials comparing niacin to placebo with background statin therapy. In this review, summarize the currently available evidence for the role of niacin treatment for reducing the risk of cardiovascular events in current practice.

Is hypertriglyceridemia atherogenic?

ASCVD reduction is based on LDL reduction, especially by statins. Highly elevated TG could be harmful, especially because of the risk of pancreatitis. Elevation of TG is mainly due to metabolic disorders and diabetes, alcohol intake and overweight. Genetic factors have been clearly identified in the most severe cases. TG have been generally considered as bystanders for cardiovascular diseases (CVD). Both biological and basic research provide strong data suggesting that TG-rich lipoproteins could be involved in the pathophysiology of CVD. Recent epidemiological and genetics studies strongly corroborate the causal role of TG in CVD. This paves the way for new approaches in the management of patients both for primary and secondary prevention.

Four Years’ Treatment Efficacy of Patients with Severe Hyperlipidemia. Lipid Lowering Drugs versus LDL-Apheresis

A total of 47 patients suffering from heterozygous hyperlipidemia were treated with LDL-apheresis (24 patients, aged 49.5±11.5 years), diet and/or lipid-lowering drugs or with diet and lipid-lowering drugs only (23 patients, aged 48.0±11.9 years). After treatment periods of 44.4±14.3 (apheresis group) and 33.5±15.9 (drug group) months, respectively, the ensuing results revealed significant differences (p<0.0001): total cholesterol decreased from 10.4 to 5.5 vs 9.9 to 8.7 mmol/l, LDL from 7.4 to 3.9 vs 6.6 to 5.2 mmol/l, triglycerides from 5.8 to 3.7 vs 4.8 to 4.1 mmol/l and the LDL/HDL-ratio decreased from 7.1 to 3.4 vs 6.7 to 5.8. In the apheresis group one patient died from myocardial infarction vs one non-fatal myocardial infarction and the manifestation of coronary heart disease in three cases in the drug group. There were no severe side-effects in either group. All patients in the apheresis group experienced an increased clinical performance. On the other hand physological well-being of these patients was lower than that of the drug group (scores 42.3±8.9 vs 50.2±9.9, p<0.002). The present trial suggests that a continuing reduction in serum lipid concentrations may lower in a dose dependent manner the risk of development and progression of coronary heart disease. With respect to clinical and laboratory results, LDL-apheresis seems safe and appears to be the most effective therapy.

Niacin

Nicotinic acid and nicotinamide, collectively referred to as niacin, are nutritional precursors of the bioactive molecules nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP). NAD and NADP are important cofactors for most cellular redox reactions, and as such are essential to maintain cellular metabolism and respiration. NAD also serves as a cosubstrate for a large number of ADP-ribosylation enzymes with varied functions. Among the NAD-consuming enzymes identified to date are important genetic and epigenetic regulators, e.g., poly(ADP-ribose)polymerases and sirtuins. There is rapidly growing knowledge of the close connection between dietary niacin intake, NAD(P) availability, and the activity of NAD(P)-dependent epigenetic regulator enzymes. It points to an exciting role of dietary niacin intake as a central regulator of physiological processes, e.g., maintenance of genetic stability, and of epigenetic control mechanisms modulating metabolism and aging. Insight into the role of niacin and various NAD-related diseases ranging from cancer, aging, and metabolic diseases to cardiovascular problems has shifted our view of niacin as a vitamin to current views that explore its potential as a therapeutic.

Remnant Cholesterol and Myocardial Infarction in Normal Weight, Overweight, and Obese Individuals from the Copenhagen General Population Study

BACKGROUND

We tested whether high remnant cholesterol is associated with high myocardial infarction risk, independent of whether an individual is normal weight, overweight, or obese.

METHODS

A total of 106216 individuals from the Copenhagen General Population Study were followed for up to 11 years, during which 1565 experienced a myocardial infarction. Individuals were grouped by clinically meaningful remnant cholesterol concentrations of &lt;0.5 mmol/L (19 mg/dL), 0.5 to 0.99 mmol/L (19–38 mg/dL), 1.0 to 1.49 mmol/L (39–58 mg/dL), and ≥1.5 mmol/L (58 mg/dL), and by body mass index (BMI) of &lt;18.5 kg/m2 (underweight), 18.5 to 24.9 kg/m2 (normal weight), 25 to 29.9 kg/m2 (overweight), and ≥30 kg/m2 (obese).

RESULTS

Median calculated remnant cholesterol was 0.40 mmol/L [interquartile range (IQR), 0.30–0.55 mmol/L] [15 mg/dL (12–21 mg/dL)] for underweight, 0.50 mmol/L (IQR, 0.37–0.71 mmol/L) [19 mg/dL (14–27 mg/dL)] for normal weight, 0.70 mmol/L (IQR, 0.49–1.00 mmol/L) [27 mg/dL (19–39 mg/dL)] for overweight, and 0.85 mmol/L (IQR, 0.61–1.20 mmol/L) [(33 mg/dL (24–46 mg/dL)] for obese individuals. On continuous scales, remnant cholesterol was positively correlated with BMI until reaching a plateau of approximately 1 mmol/L (39 mg/dL) at BMI &gt;35 kg/m2. R2 from an unadjusted linear regression for the correlation between calculated remnant cholesterol and BMI was 12%. Stepwise higher remnant cholesterol was associated with stepwise higher myocardial infarction risk in a similar pattern for normal weight, overweight, and obese individuals. When compared with individuals with remnant cholesterol &lt;0.5 mmol/L (19 mg/dL), individuals with remnant cholesterol ≥1.5 mmol/L (58 mg/dL) had hazard ratios for myocardial infarction of 2.0 (95% CI, 1.3–3.2) for normal weight, 1.9 (95% CI, 1.4–2.6) for overweight, and 2.3 (95% CI, 1.4–3.5) for obese individuals. Directly measured remnant cholesterol increased 0.91 mmol/L (95% CI, 0.89–0.94 mmol/L) [35 mg/dL (34–36 mg/dL)] per 1 mmol/L (39 mg/dL) increase in calculated remnant cholesterol.

CONCLUSIONS

Remnant cholesterol and BMI were positively correlated; however, high remnant cholesterol was associated with higher myocardial infarction risk across the examined BMI subcategories, indicating that remnant cholesterol is a risk factor for myocardial infarction independent of overweight and obesity.

High-density Lipoprotein and Low-density Lipoprotein Therapeutic Approaches in Acute Coronary Syndromes

BACKGROUND

Low-density lipoprotein cholesterol (LDL), and especially its oxidized form, renders the atherosclerotic plaque vulnerable to rupture in acute coronary syndromes (ACS). On the other hand, high-density lipoprotein (HDL) is considered an anti-atherogenic molecule. The more recent HDL-targeted drugs may prove to be superior to those used before. Indeed, delipidated HDL and HDL mimetics are efficient in increasing HDL levels, while the apoA-I upregulation with RVX-208 appears to offer a clinical benefit which is beyond the HDL related effects. HDL treatment however has not shown a significant improvement in the outcomes of patients with ACS so far, studies have therefore focused again on LDL. In addition to statins and ezetimibe, novel drugs such as PSCK9 inhibitors and apolipoprotein B inhibitors appear to be both effective and safe for patients with hyperlipidemia.

CONCLUSION

Data suggest these could potentially improve the cardiovascular outcomes of patient with ACS. Yet, there is still research to be done, in order to confirm whether ACS patients would benefit from LDL- or HDL-targeted therapies or a combination of both.

Apolipoprotein C-II: New findings related to genetics, biochemistry, and role in triglyceride metabolism

Apolipoprotein C-II (apoC-II) is a small exchangeable apolipoprotein found on triglyceride-rich lipoproteins (TRL), such as chylomicrons (CM) and very low-density lipoproteins (VLDL), and on high-density lipoproteins (HDL), particularly during fasting. ApoC-II plays a critical role in TRL metabolism by acting as a cofactor of lipoprotein lipase (LPL), the main enzyme that hydrolyses plasma triglycerides (TG) on TRL. Here, we present an overview of the role of apoC-II in TG metabolism, emphasizing recent novel findings regarding its transcriptional regulation and biochemistry. We also review the 24 genetic mutations in the APOC2 gene reported to date that cause hypertriglyceridemia (HTG). Finally, we describe the clinical presentation of apoC-II deficiency and assess the current therapeutic approaches, as well as potential novel emerging therapies.

Role of Niacin in Current Clinical Practice: A Systematic Review

BACKGROUND

Niacin, a potent high-density lipoprotein cholesterol-raising drug, seems an attractive approach to reduce cardiac events in patients with or at risk of atherosclerotic cardiovascular disease. However, previous evidence for niacin has been challenged recently by negative outcomes in 2 large, randomized, controlled trials comparing niacin to placebo with background statin therapy. We studied the currently available evidence for the role of niacin treatment for reducing the risk of cardiovascular events in current practice.

METHODS

A systematic review of randomized controlled trials in the MEDLINE, EMBASE, CINAHL, and Cochrane databases comparing niacin alone or combined with statin therapy was performed. We extracted trial level data, including basic characteristics and number of patients enrolled, duration of follow up, occurrence of adverse events, and cardiovascular-related outcomes. Random effects meta-analysis was conducted to estimate the risk ratio (RR) for individual trial endpoints.

RESULTS

Thirteen trials (N = 35,206) were selected for final analysis. The mean follow-up duration was 32.8 months. Overall, niacin led to significant increases in serum high-density lipoprotein cholesterol levels from baseline trial enrolment by 21.4%, 9.31 (95% confidence interval [CI] 5.11-13.51) mg/dL. However, we did not observe any differences in all-cause mortality rates (RR 0.99; 95% CI 0.88-1.12) between niacin and control arms. Further, niacin treatment was associated with a trend toward lower risk of cardiovascular mortality (RR 0.91; 95% CI 0.81-1.02), coronary death (RR 0.93; 95% CI 0.78-1.10), nonfatal myocardial infarction (RR 0.85; 95% CI 0.73-1.0), revascularization (coronary and noncoronary) (RR 0.83; 95% CI 0.65-1.06), and stroke (RR 0.89; 95% CI 0.72-1.10), compared with control.

CONCLUSION

Niacin therapy does not lead to significant reductions in total or cause-specific mortality or recurrent cardiovascular events among persons with or at risk of atherosclerotic cardiovascular disease.

Measuring niacin-associated skin toxicity (NASTy) stigmata along with symptoms to aid development of niacin mimetics

Though cardioprotective, niacin monotherapy is limited by unpleasant cutaneous symptoms mimicking dermatitis: niacin-associated skin toxicity (NASTy). Niacin is prototypical of several emerging drugs suffering off-target rubefacient properties whereby agonizing the GPR109A receptor on cutaneous immune cells provokes vasodilation, prompting skin plethora and rubor, as well as dolor, tumor, and calor, and systemically, heat loss, frigor, chills, and rigors. Typically, NASTy effects are described by subjective patient-reported perception, at best semi-quantitative and bias-prone. Conversely, objective, quantitative, and unbiased methods measuring NASTy stigmata would facilitate research to abolish them, motivating development of several objective methods. In early drug development, such methods might better predict clinical tolerability in larger clinical trials. Measuring cutaneous stigmata may also aid investigations of vasospastic, ischemic, and inflammatory skin conditions. We present methods to measure NASTy physical stigmata to facilitate research into novel niacin mimetics/analogs, detailing characteristics of each technique following niacin, and how NASTy stigmata relate to symptom perception. We gave niacin orally and measured rubor by colorimetry and white-light spectroscopy, plethora by laser Doppler flowmetry, and calor/frigor by thermometry. Surprisingly, each stigma's abruptness predicted symptom perception, whereas peak intensity did not. These methods are adaptable to study other rubefacient drugs or dermatologic and vascular disorders.

Niacin Promotes Cardiac Healing after Myocardial Infarction through Activation of the Myeloid Prostaglandin D2 Receptor Subtype 1

Niacin is a well established drug used to lower cholesterol and prevent cardiovascular disease events. However, niacin also causes cutaneous flushing side effects due to release of the proresolution mediator prostaglandin D₂ (PGD₂). Recent randomized clinical trials have demonstrated that addition of niacin with laropiprant [a PGD₂ receptor subtype 1 (DP1) blocker] to statin-based therapies does not significantly decrease the risk of cardiovascular disease events, but increases the risk of serious adverse events. Here, we tested whether, and how, niacin beneficial effects on myocardial ischemia require the activation of the PGD₂/DP1 axis. Myocardial infarction (MI) was reproduced by ligation of the left anterior descending branch of the coronary artery in mice. We found that niacin increased PGD₂ release in macrophages and shifted macrophages to M2 polarization both in vitro and in vivo by activation of DP1 and accelerated inflammation resolution in zymosan-induced peritonitis in mice. Moreover, niacin treatment facilitated wound healing and improved cardiac function after MI through DP1-mediated M2 bias and timely resolution of inflammation in infarcted hearts. In addition, we found that niacin intake also stimulated M2 polarization of peripheral monocytes in humans. Collectively, niacin promoted cardiac functional recovery after ischemic myocardial infarction through DP1-mediated M2 polarization and timely resolution of inflammation in hearts. These results indicated that DP1 inhibition may attenuate the cardiovascular benefits of niacin.

Pleiotropic effects of niacin: Current possibilities for its clinical use

Niacin was the first hypolipidemic drug to significantly reduce both major cardiovascular events and mortality in patients with cardiovascular disease. Niacin favorably influences all lipoprotein classes, including lipoprotein[a],and belongs to the most potent hypolipidemic drugs for increasing HDL-C. Moreover, niacin causes favorable changes to the qualitative composition of lipoprotein HDL. In addition to its pronounced hypolipidemic action, niacin exerts many other, non-hypolipidemic effects (e.g., antioxidative, anti-inflammatory, antithrombotic), which favorably influence the development and progression of atherosclerosis. These effects are dependent on activation of the specific receptor HCA2. Recent results published by the two large clinical studies, AIM-HIGH and HPS2-THRIVE, have led to the impugnation of niacin's role in future clinical practice. However, due to several methodological flaws in the AIM-HIGH and HPS2-THRIVE studies, the pleiotropic effects of niacin now deserve thorough evaluation. This review summarizes the present and possible future use of niacin in clinical practice in light of its newly recognized pleiotropic effects.

Review: Fibrates: therapeutic review

As agonists of the peroxisome proliferator-activated receptor α (PPARα), fibrates are established, effective and well-tolerated agents in the management of atherogenic dyslipidaemia. Key actions of fibrates include a reduction in elevated triglyceride levels (by up to 50%) and a rise in high-density lipoprotein cholesterol (HDL-C) concentrations (typically by 5—15%). Fibrates promote a shift from small, dense low-density lipoprotein (LDL) to larger more buoyant particles, which are less susceptible to oxidation and possess higher binding affinity for removal by the non-atherogenic LDL receptor pathway. Thus, fibrates can correct lipid abnormalities commonly observed in patients with type 2 diabetes and metabolic syndrome. Clinical evidence has demonstrated the value of fibrate therapy in secondary and primary prevention settings, as well as in patients with type 2 diabetes. However, FIELD, the largest fibrate study to date in diabetic patients, predominantly in a primary prevention setting, showed a non-significant 11% reduction in the primary end point of coronary heart disease death and non-fatal myocardial infarction with fenofibrate, although total cardiovascular events, corresponding to the secondary end point, were significantly reduced by 11% (p=0.035). It is possible that risk reduction with fenofibrate may have been attenuated by the two-fold greater drop-in use of statin therapy in the placebo group. However, the interesting results of fenofibrate on attenuation of microangiographic symptomatology potentially suggest a new recommendation for fibrate therapy, although further studies are required to validate these findings.

Niacin Alternatives for Dyslipidemia: Fool's Gold or Gold Mine? Part II: Novel Niacin Mimetics

Two cardiovascular outcome trials established niacin 3 g daily prevents hard cardiac events. However, as detailed in part I of this series, an extended-release (ER) alternative at only 2 g nightly demonstrated no comparable benefits in two outcome trials, implying the alternative is not equivalent to the established cardioprotective regimen. Since statins leave a significant treatment gap, this presents a major opportunity for developers. Importantly, the established regimen is cardioprotective, so the pathway is likely beneficial. Moreover, though effective, the established cardioprotective regimen is cumbersome, limiting clinical use. At the same time, the ER alternative has been thoroughly discredited as a viable substitute for the established cardioprotective regimen. Therefore, by exploiting the pathway and skillfully avoiding the problems with the established cardioprotective regimen and the ER alternative, developers could validate cardioprotective variations facing little meaningful competition from their predecessors. Thus, shrewd developers could effectively tap into a gold mine at the grave of the ER alternative. The GPR109A receptor was discovered a decade ago, leading to a large body of evidence commending the niacin pathway to a lower cardiovascular risk beyond statins. While mediating niacin's most prominent adverse effects, GPR109A also seems to mediate anti-lipolytic, anti-inflammatory, and anti-atherogenic effects of niacin. Several developers are investing heavily in novel strategies to exploit niacin's therapeutic pathways. These include selective GPR109A receptor agonists, niacin prodrugs, and a niacin metabolite, with encouraging early phase human data. In part II of this review, we summarize the accumulated results of these early phase studies of emerging niacin mimetics.

All cholesterol-lowering interventions are expected to reduce stroke: Confirmatory data from IMPROVE-IT

The relationship of cholesterol with stroke is much less clear than its relationship with myocardial infarction, thus confounding the interpretation of results with cholesterol-lowering trials (Di Napoli et al., 2002) [1], (De Caterina et al., 2010) [2]). IMPROVE-IT data ((Cannon et al. 2015) [3]), showing a 13.3% reduction in total cholesterol at one year in association with a hazard ratio (HR) of 0.i86 for total stroke during the trial, are very closely aligned with the relative risk of 0.90 predicted based on the totality of lipid lowering interventions ((De Caterina et al., 2016) [4]). We here provide the data from the original trials used to construct this meta-analysis, with the now added additional data from IMPROVE-IT, well-fitting the previously found meta-regression line. These data are important to predict stroke outcomes in currently ongoing trials now testing PCSK9 or cholesterol ester transfer protein inhibitors.

Recent advances in the pharmacological management of hypercholesterolaemia

The recent developments in pharmacological interventions that reduce LDL cholesterol have been remarkable, coming more than a decade after the approval of the last LDL-cholesterol-lowering drug, the cholesterol absorption inhibitor ezetimibe. Within just a few years, four new LDL-cholesterol-lowering agents have received regulatory approval. Lomitapide and mipomersen inhibit the production of LDL, but also increase hepatic fat and are licensed specifically for homozygous familial hypercholesterolaemia. Alirocumab and evolocumab are monoclonal antibodies that bind to proprotein convertase subtilisin/kexin type 9 (PCSK9), lowering LDL by about 50-60%. These drugs are approved for use in patients with cardiovascular disease or familial hypercholesterolaemia whose LDL cholesterol levels are insufficiently controlled on standard agents. Although definitive clinical efficacy and long-term safety data are still needed, antibody-based PCSK9 inhibitors promise to meet much of the unmet medical need in the treatment of raised LDL cholesterol. However, several additional approaches to inhibiting PCSK9, as well as other classes of LDL-lowering therapies, are in clinical development. Here we summarise the science behind the development of the newly approved LDL-cholesterol-lowering drugs and critically review their efficacy and safety data, highlighting unanswered research questions. Finally, we discuss emerging LDL-lowering therapies in clinical development.

Niacin Alternatives for Dyslipidemia: Fool's Gold or Gold Mine? Part I: Alternative Niacin Regimens

Niacin was the first drug demonstrating lowered cholesterol prevents coronary heart disease (CHD) events, with two clinical CHD outcome studies establishing a cardioprotective niacin regimen: 1 g thrice daily with meals. Though cardioprotective, skin toxicity limits niacin's use, fostering several variations to improve tolerability. One of these, an extended-release (ER) alternative, proved immensely successful commercially, dominating clinical practice despite departing from the established regimen in several critical ways. Hence, improved tolerability may have come at the cost of diminished efficacy, posing a conundrum: Does it still help the population at risk for CHD to broaden a drug's acceptance by "watering it down"? This question is crucial at this stage now that the ER alternative failed to recapitulate the benefits of the established cardioprotective niacin regimen in two trials of the alternative approach: AIM-HIGH and HPS2-THRIVE. Part I of this review discusses how vastly the ER alternative departs from the established cardioprotective regimen, why that is important physiologically, and how it may explain the findings of AIM-HIGH and HPS2-THRIVE. Given important gaps left by statin therapy, the established cardioprotective niacin regimen remains an important evidence-based therapy for the statin intolerant or statin averse.

Systematic review of CETP inhibitors for increasing high-density lipoprotein cholesterol: where do these agents stand in the approval process?

The role that low levels of high-density lipoprotein cholesterol (HDL-C) plays in coronary artery disease and ischemic heart disease is well established. As such, therapies targeting low HDL-C levels have been of great therapeutic interest. These therapies include nonpharmacological methods such as exercise, tobacco cessation, weight reduction, moderate alcohol intake, and increasing dietary monounsaturated fatty acids and polyunsaturated fatty acids. Additionally, pharmacological methods of increasing HDL-C have been of great interest, with 2 classes of drugs, fibric acid derivatives and nicotinic acid, and have mixed trial results when used on top of standard lipid therapy. However, a new class of medications, cholesteryl ester transfer protein inhibitors, has shown increases in HDL-C of over 100%. However, early trial results with torcetrapib showed an increase in mortality, although this was attributed to off-target toxicity. Dalcetrapib was found to be safer than torcetrapib, but data released in 2012 showed no additional benefit in patients suffering an acute coronary syndrome event. Two newer agents, anacetrapib and evacetrapib, in early-phase clinical trials have shown to be safer than torcetrapib and significantly more potent than dalcetrapib (both increase HDL-C by a greater amount and both have a significant effect on low-density lipoprotein cholesterol). It remains to be seen whether the use of cholesteryl ester transfer protein inhibitors will result in clinical benefit in large, randomized double-blind trials and whether any agents in this class will ever be approved for clinical use.

Nonstatin therapies for management of dyslipidemia: a review

PURPOSE

Cardiovascular disease (CVD) is the leading cause of morbidity and mortality in the United States. Recently published cholesterol treatment guidelines emphasize the use of statins as the preferred treatment strategy for both primary and secondary prevention of CVD. However, the optimal treatment strategy for patients who cannot tolerate statin therapy or those who need additional lipid-lowering therapy is unclear in light of recent evidence that demonstrates a lack of improved cardiovascular outcomes with combination therapy. The purpose of this review is to summarize and interpret evidence that evaluates nonstatin drug classes in reducing cardiovascular outcomes, to provide recommendations for use of nonstatin therapies in clinical practice, and to review emerging nonstatin therapies for management of dyslipidemia.

METHODS

Relevant articles were identified through searches of PubMed, International Pharmaceutical Abstracts, and the Cochrane Database of Systematic Reviews by using the terms niacin, omega-3 fatty acids (FAs), clofibrate, fibrate, fenofibrate, fenofibric acid, gemfibrozil, cholestyramine, colestipol, colesevelam, ezetimibe, proprotein convertase subtilisin/kexin 9 (PCSK9), cholesteryl ester transfer protein (CETP), and cardiovascular outcomes. Only English language, human clinical trials, meta-analyses, and systematic reviews were included. Additional references were identified from citations of published articles.

FINDINGS

Niacin may reduce cardiovascular events as monotherapy; however, recent trials in combination with statins have failed to show a benefit. Trials with omega-3 FAs have failed to demonstrate significant reductions in cardiovascular outcomes. Fibrates may improve cardiovascular outcomes as monotherapy; however, trials in combination with statins have failed to show a benefit, except in those with elevated triglycerides (>200 mg/dL) or low HDL-C (<40 mg/dL). There is a lack of data that evaluates bile acid sequestrant in combination with statin therapy on reducing cardiovascular events. Ezetimibe-statin combination therapy can reduce cardiovascular outcomes in those with chronic kidney disease and following vascular surgery or acute coronary syndrome. Long-term effects of emerging nonstatin therapies (CETP and PCSK9 inhibitors) are currently being evaluated in ongoing Phase III trials.

IMPLICATIONS

Nonstatin therapies have a limited role in reducing cardiovascular events in those maintained on guideline-directed statin therapy. In certain clinical situations, such as patients who are unable to tolerate statin therapy or recommended intensities of statin therapy, those with persistent severe elevations in triglycerides, or patients with high cardiovascular risk, some nonstatin therapies may be useful in reducing cardiovascular events. Future research is needed to evaluate the role of nonstatin therapies in those who are unable to tolerate guideline-directed statin doses.

Lowering triglycerides to modify cardiovascular risk: will icosapent deliver?

Despite the clinical benefits of lowering levels of low-density lipoprotein cholesterol, many patients continue to experience cardiovascular events. This residual risk suggests that additional risk factors require aggressive modification to result in more effective prevention of cardiovascular disease. Hypertriglyceridemia has presented a considerable challenge with regard to understanding its role in the promotion of cardiovascular risk. Increasing evidence has established a clear causal role for elevated triglyceride levels in vascular risk. As a result, there is increasing interest in the development of specific therapeutic strategies that directly target hypertriglyceridemia. This has seen a resurgence in the use of omega-3 fatty acids for the therapeutic lowering of triglyceride levels. The role of these agents and other emerging strategies to reduce triglyceride levels in order to decrease vascular risk are reviewed.

Lipoprotein (a): a Unique Independent Risk Factor for Coronary Artery Disease

The current epidemic affecting Indians is coronary artery disease (CAD), and is currently one of the most common causes of mortality and morbidity in developed and developing countries. The higher rate of CAD in Indians, as compared to people of other ethnic origin, may indicate a possible genetic susceptibility. Hence, Lp(a), an independent genetic risk marker for atherosclerosis and cardiovascular disease assumes great importance. Lp(a), an atherogenic lipoprotein, contains a cholesterol rich LDL particle, one molecule of apolipoprotein B-100 and a unique protein, apolipoprotein (a) which distinguishes it from LDL. Apo(a) is highly polymorphic and an inverse relationship between Lp(a) concentration and apo(a) isoform size has been observed. This is genetically controlled suggesting a functional diversity among the apo(a) isoforms. The LPA gene codes for apo(a) whose genetic heterogeneity is due to variations in its number of kringles. The exact pathogenic mechanism of Lp(a) is still not completely elucidated, but the structural homology of Lp(a) with LDL and plasmin is possibly responsible for its acting as a link between atherosclerosis and thrombosis. Upper limits of normal Lp(a) levels have not been defined for the Indian population. A cut off limit of 20 mg/dL has been suggested while for the Caucasian population it is 30 mg/dL. Though a variety of assays are available for its measurement, standardization of the analytical method is highly complicated as a majority of the methods are affected by the heterogeneity in apo(a) size. No therapeutic drug selectively targets Lp(a) but recently, new modifiers of apo(a) synthesis are being considered.

Extreme nonfasting remnant cholesterol vs extreme LDL cholesterol as contributors to cardiovascular disease and all-cause mortality in 90000 individuals from the general population

BACKGROUND

Increased nonfasting remnant cholesterol, like increased LDL cholesterol, is causally associated with increased risk for ischemic heart disease (IHD). We tested the hypothesis that extreme concentrations of nonfasting remnant and LDL cholesterol are equal contributors to the risk of IHD, myocardial infarction (MI), and all-cause mortality.

METHODS

We compared stepwise increasing concentrations of nonfasting remnant and LDL cholesterol for association with risk of IHD, MI, and all-cause mortality in approximately 90 000 individuals from the Danish general population. During up to 22 years of complete follow-up, 4435 participants developed IHD, 1722 developed MI, and 8121 died.

RESULTS

Compared with participants with nonfasting remnant cholesterol <0.5 mmol/L (19.3 mg/dL), hazard ratios for IHD ranged from 1.3 (95% CI 1.1-1.5) for remnant cholesterol of 0.5-0.99 mmol/L (19.3-38.2 mg/dL) to 2.4 (1.9-2.9) for remnant cholesterol of ≥1.5 mmol/L (58 mg/dL) (P for trend <0.001). Compared with participants with LDL cholesterol <3.0 mmol/L (115.8 mg/dL), hazard ratios for IHD ranged from 1.3 (1.1-1.5) for LDL cholesterol of 3-3.99 mmol/L (115.8-154 mg/dL) to 2.3 (1.9-2.8) for LDL cholesterol of ≥5 mmol/L (193 mg/dL) (P < 0.001). Corresponding hazard ratios for MI ranged from 1.8 (1.4-2.3) to 3.4 (2.5-4.8) for remnant cholesterol (P < 0.001), and from 1.7 (1.4-2.2) to 4.7 (3.5-6.3) for LDL cholesterol (P < 0.001). Nonfasting remnant cholesterol concentrations were associated stepwise with all-cause mortality ranging from hazard ratio 1.0 (0.9-1.1) to 1.6 (1.4-1.9) (P < 0.001), whereas LDL cholesterol concentrations were associated with decreased all-cause mortality risk in a U-shaped pattern, with hazard ratios from 0.8 (0.7-0.8) to 0.9 (0.8-1.0) (P = 0.002). After mutual adjustment, LDL cholesterol best predicted MI, and remnant cholesterol best predicted all-cause mortality.

CONCLUSIONS

Both lipoproteins were associated equally with risk of IHD and MI; however, only nonfasting remnant cholesterol concentrations were associated stepwise with increased all-cause mortality risk.

Effects of HDL-modifiers on cardiovascular outcomes: a meta-analysis of randomized trials

BACKGROUND AND AIM

High density lipoproteins (HDL) have been addressed as a potential strategy for cardiovascular prevention, with great controversies on pharmacological approaches for HDL-elevation. Our aim was to compare HDL-rising treatment with niacin or CETP-inhibitors with optimal medical therapy in cardiovascular outcome.

METHODS AND RESULTS

Randomized trials were searched. Primary endpoint was cardiovascular death, secondary were: non fatal myocardial infarction; coronary revascularization; cerebrovascular accidents and safety endpoints. As many as 18 randomized trials, for a total of 69,515 patients, were included. HDL-modifiers did not reduce cardiovascular mortality (2.3%vs3.4%; OR [95%CI] = 0.96 [0.87-1.05], p = 0.37, phet = 0.58), with no benefit from niacin/CETP inhibitors according to patients' risk profile (beta [95%CI] = -0.14 [-0.29 to 0.02], p = 0.09) or the amount of HDL increase (beta [95%CI] = 0.014 [-0.008 to 0.04], p = 0.21). Niacin but not CETP-I reduced myocardial infarction and coronary revascularization, but higher rate of SAE occurred with HDL-modifiers (OR [95%CI] = 1.24 [1.18-1.31], p < 0.00001, phet = 0.02), in particular new onset of diabetes with niacin and worsening of hypertension with CETP-inhibitors.

CONCLUSIONS

Niacin and CETP inhibitors do not influence cardiovascular mortality. Significant benefits in MI and coronary revascularization were observed with niacin, despite the higher occurrence of diabetes.

Triglycerides and cardiovascular disease

After the introduction of statins, clinical emphasis first focussed on LDL cholesterol-lowering, then on the potential for raising HDL cholesterol, with less focus on lowering triglycerides. However, the understanding from genetic studies and negative results from randomised trials that low HDL cholesterol might not cause cardiovascular disease as originally thought has now generated renewed interest in raised concentrations of triglycerides. This renewed interest has also been driven by epidemiological and genetic evidence supporting raised triglycerides, remnant cholesterol, or triglyceride-rich lipoproteins as an additional cause of cardiovascular disease and all-cause mortality. Triglycerides can be measured in the non-fasting or fasting states, with concentrations of 2-10 mmol/L conferring increased risk of cardiovascular disease, and concentrations greater than 10 mmol/L conferring increased risk of acute pancreatitis and possibly cardiovascular disease. Although randomised trials showing cardiovascular benefit of triglyceride reduction are scarce, new triglyceride-lowering drugs are being developed, and large-scale trials have been initiated that will hopefully provide conclusive evidence as to whether lowering triglycerides reduces the risk of cardiovascular disease.

Remnant cholesterol and ischemic heart disease

PURPOSE OF REVIEW

To review recent advances in the field of remnant cholesterol as a contributor to the development of ischemic heart disease (IHD).

RECENT FINDINGS

Epidemiologic, mechanistic, and genetic studies all support a role for elevated remnant cholesterol (=cholesterol in triglyceride-rich lipoproteins) as a contributor to the development of atherosclerosis and IHD. Observational studies show association between elevated remnant cholesterol and IHD, and mechanistic studies show remnant cholesterol accumulation in the arterial wall like LDL-cholesterol (LDL-C) accumulation. Furthermore, large genetic studies show evidence of remnant cholesterol as a causal risk factor for IHD independent of HDL-cholesterol levels. Genetic studies also show that elevated remnant cholesterol is associated with low-grade inflammation, whereas elevated LDL-C is not. There are several pharmacologic ways of lowering remnant cholesterol levels; however, it remains to be seen in large randomized clinical intervention trials if lowering of remnant cholesterol, in individuals with elevated levels, will reduce the risk of IHD.

SUMMARY

Evidence is emerging for elevated remnant cholesterol being a causal risk factor for IHD. Elevated remnant cholesterol levels likely are part of the explanation of the residual risk of IHD observed after LDL-C has been lowered to recommended levels.

Effect on cardiovascular risk of high density lipoprotein targeted drug treatments niacin, fibrates, and CETP inhibitors: meta-analysis of randomised controlled trials including 117,411 patients

OBJECTIVE

To investigate the effects on cardiovascular outcomes of drug interventions that increase high density lipoprotein levels.

DESIGN

Meta-analysis.

STUDIES REVIEWED

Therapeutic benefit of niacin, fibrates, and cholesteryl ester transfer protein (CETP) inhibitors on cardiovascular events (all cause mortality, coronary heart disease mortality, non-fatal myocardial infarction, and stroke).

RESULTS

117,411 patients were randomised in a total of 39 trials. All interventions increased the levels of high density lipoprotein cholesterol. No significant effect was seen on all cause mortality for niacin (odds ratio 1.03, 95% confidence interval 0.92 to 1.15, P=0.59), fibrates (0.98, 0.89 to 1.08, P=0.66), or CETP inhibitors (1.16, 0.93 to 1.44, P=0.19); on coronary heart disease mortality for niacin (0.93, 0.76 to 1.12, P=0.44), fibrates (0.92, 0.81 to 1.04, P=0.19), or CETP inhibitors (1.00, 0.80 to 1.24, P=0.99); or on stroke outcomes for niacin (0.96, 0.75 to 1.22, P=0.72), fibrates (1.01, 0.90 to 1.13, P=0.84), or CETP inhibitors (1.14, 0.90 to 1.45, P=0.29). In studies with patients not receiving statins (before the statin era), niacin was associated with a significant reduction in non-fatal myocardial infarction (0.69, 0.56 to 0.85, P=0.0004). However, in studies where statins were already being taken, niacin showed no significant effect (0.96, 0.85 to 1.09, P=0.52). A significant difference was seen between these subgroups (P=0.007). A similar trend relating to non-fatal myocardial infarction was seen with fibrates: without statin treatment (0.78, 0.71 to 0.86, P<0.001) and with all or some patients taking statins (0.83, 0.69 to 1.01, P=0.07); P=0.58 for difference.

CONCLUSIONS

Neither niacin, fibrates, nor CETP inhibitors, three highly effective agents for increasing high density lipoprotein levels, reduced all cause mortality, coronary heart disease mortality, myocardial infarction, or stroke in patients treated with statins. Although observational studies might suggest a simplistic hypothesis for high density lipoprotein cholesterol, that increasing the levels pharmacologically would generally reduce cardiovascular events, in the current era of widespread use of statins in dyslipidaemia, substantial trials of these three agents do not support this concept.