Efficacy and safety of high-density lipoprotein cholesterol-increasing compounds: a meta-analysis of randomized controlled trials

Atherosclerosis imaging as a benchmark in the development of novel cardiovasular drugs

PURPOSE OF REVIEW

Imaging of the arterial wall yields validated surrogate markers that can provide an early indication with regards to efficacy of novel cardiovascular drugs. This paper attempts to address the use of atherosclerosis imaging as a benchmarking tool for a well informed decision whether to proceed to large morbidity and mortality studies in the assessment of a novel therapeutic strategy.

RECENT FINDINGS

Imaging of the artery wall can be used to evaluate individual cardiovascular risk and has additive value over conventional risk scores as it directly addresses the disease process. In controlled clinical trials, vascular imaging has shown that the efficacy of lipid-modifying pharmacotherapy can be evaluated in both high and low-risk populations and that the findings parallel outcomes of clinical studies with similar interventions.

SUMMARY

Arterial imaging may provide the first glimpse of the efficacy or failure of a novel strategy to combat atherosclerosis. These findings suggest that vascular imaging could be employed to probe whether or not a large morbidity and mortality endpoint study should be the next step in a clinical development program.

HDL-c is a powerful lipid predictor of cardiovascular diseases

RELATIONSHIP BETWEEN HDL-C AND CARDIOVASCULAR DISEASES: Beyond the role of low-density lipoprotein cholesterol (LDL-c) in the development of atherosclerosis, growing evidence suggest that high-density lipoprotein cholesterol (HDL-c) is a powerful predictor of cardiovascular disease. Indeed, epidemiological, mechanistic and intervention studies suggest that low HDL-c is a major cardiovascular risk factor and that increasing HDL-c plasma levels may be beneficial, particularly in patients with low HDL-c levels. The inverse association between HDL-c concentrations and cardiovascular risk is continuous without threshold value. Thus, any categorical definition of low HDL-c is arbitrary. PROTECTIVE EFFECTS OF HDL: HDL particles are highly heterogeneous in structure and intravascular metabolism. Antiatherogenic properties of HDL include its role in the reverse cholesterol transfer, besides its antioxidant, anti-inflammatory and antiapoptotic activities. WHAT SHOULD CLINICIANS DO?: From a practical point of view, HDL-c should be systematically measured to assess the cardiovascular risk in patients. The first step to consider in subjects with low HDL-c is to look for specific causes and give advice to change inappropriate lifestyle components associated with low HDL-c, such as smoking, lack of physical exercise and overweight. Patients with very low HDL-c need a thorough evaluation by specialist physicians. Statins are associated with a modest increase of HDL-c (5%) while fibrates and nicotinic acid increase HDL-c by 10% and 20% respectively.

The role of fibrates in the prevention of cardiovascular disease--a pooled meta-analysis of long-term randomized placebo-controlled clinical trials

BACKGROUND

Fibrates are effective antilipidemic agents with peroxisome proliferator-activated receptor agonist activity, but clinical trial data on their role in cardiovascular prevention are conflicting. We conducted a systematic review and meta-analysis of randomized clinical trials to evaluate their role in prevention of cardiovascular events.

METHODS

A total of 36,489 patients from 10 published randomized placebo-controlled trials were analyzed using the Mantel-Haenszel fixed-effects model. Odds ratios were computed for cardiovascular outcomes from data pooled from the selected trials, and statistical significance was tested using the z-test statistic (2-sided alpha error <.05).

RESULTS

Fibrates significantly reduced plasma total cholesterol and triglyceride levels by about 8% and 30%, respectively, and raised high-density lipoprotein cholesterol levels by about 9% compared with placebo. The odds of all-cause mortality tended to be higher (P = .08), and the odds of noncardiovascular mortality were significantly higher (P = .004) with the use of fibrates. However, these significant differences did not persist after exclusion of trials using clofibrate as the study drug. Fibrates did not significantly reduce the odds of cardiovascular mortality (P = .68), fatal myocardial infarction (MI) (P = .76), or stroke (P = .56). On the other hand, fibrates significantly reduced the odds of nonfatal MI by about 22% (P < .00001). The odds of developing cancer were not significantly higher with the use of fibrates (P = .98), nor were the odds of cancer-related death (P = .17).

CONCLUSIONS

In conclusion, our meta-analysis revealed that the long-term use of fibrates significantly reduces the occurrence of nonfatal MI but has no significant effect on other adverse cardiovascular outcomes.

The role of CETP inhibition in dyslipidemia

Cholesteryl ester transfer protein (CETP) inhibitors are currently being investigated because of their ability to increase high-density lipoprotein cholesterol levels. In various metabolic settings, the relationship between CETP and lipoprotein metabolism is complex and may depend largely on the concentration of triglyceride-rich lipoproteins. Two CETP inhibitors, JTT-705 and torcetrapib, are in an advanced phase of development. Following hopeful intermediate results, a large endpoint study using torcetrapib has just been discontinued due to increased mortality in torcetrapib-treated subjects. In this review we summarize clinical data on the use of CETP inhibitors.

HDL-C in post-menopausal women: An important therapeutic target

Coronary heart disease is a major cause of mortality in women in Western industrialised countries, particularly after the age of 50 years, coinciding with the onset of the menopause and potentially adverse metabolic changes that occur during the transitional peri-menopausal and post-menopausal periods. Dyslipidaemia characterised by increases in plasma levels of low-density lipoprotein cholesterol (LDL-C), triglycerides and lipoprotein(a) and a decrease in high-density lipoprotein cholesterol (HDL-C) together with the emergence of other diagnostic features of the metabolic syndrome are key factors that increase cardiovascular risk. Treatment beyond LDL-C with a combination of different lipid-modifying therapies may therefore be of greater importance in women than men. Fibrates and nicotinic acid are two treatments that may be added to primary statin therapy. Fibrates are more effective in lowering elevated triglycerides, whereas nicotinic acid is more effective in raising HDL-C. Although there is clearly a need for clinical trials in women, the available data suggests that combination lipid-modifying therapy is a logical treatment strategy in this high-risk patient group.

Validation of a questionnaire to assess niacin-induced cutaneous flushing

BACKGROUND

Niacin is currently the most effective approved agent for raising high-density lipoprotein cholesterol. However, niacin-induced cutaneous flushing (redness, warmth, tingling and/or itching) significantly limits patient acceptance. To further characterize flushing, a patient-reported Flushing Symptom Questionnaire (FSQ) was developed and validated.

METHODS

The FSQ was validated in an 8-week, randomized, double-blind, placebo-controlled trial of extended-release (ER) niacin and placebo. The primary flushing endpoint of the study was based on the single Global Flushing Severity Score (GFSS), an item within the FSQ, which assesses overall flushing severity on a 0-10 discretized analog scale.

RESULTS

A total of 175 patients were randomized to one of four treatment groups (sequences of placebo and ER niacin [given as niacin (NIASPAN) 1 g (N1) and 2g (N2)]. Test-retest reliability and reproducibility coefficients for the single-item GFSS were all above 0.75. Construct validity was supported by moderate to strong correlations (r > 0.5) with other FSQ items. All FSQ item scores and specifically the GFSS discriminated between treatment groups and demonstrated expected relationships with predefined known groups. The GFSS demonstrated high responsiveness in patients who switched from ER niacin to placebo. The ability of the GFSS and GFBS to discriminate changes in flushing symptoms in patients who increased drug dose was less than expected possibly due to accommodation to the flushing effects of niacin over time; differential drop-out due to flushing; and/or FSQ items not being sensitive enough to detect a change that was present.

CONCLUSIONS

The FSQ items and specifically the Global Flushing Severity Score (GFSS), are reliable and valid measures to assess niacin-induced flushing.

Recent trials of lipid lowering

The global burden of coronary artery disease has pushed lipid-lowering therapy to the forefront of medical management of this condition. Recent clinical trials have compared the efficacy of more intensive lipid lowering with statins against the normal standard of care. Other agents such as fibrates, glitazones, which also favourably modify lipid levels have also been assessed recently. This narrative review summarises the key recent clinical trials of lipid lowering since 2004 and their implications for future patient care.

The significance of low HDL-cholesterol levels in an ageing society at increased risk for cardiovascular disease

In most developed and developing countries, the proportion of the population aged 60 years or more is growing faster than any other age group. Given that the vast majority of cardiovascular events occur in older individuals, new thinking is needed to reduce their risk. Epidemiological studies have shown an increasing prevalence of the metabolic syndrome with age, driven by nutrition inappropriate for a modern sedentary lifestyle. A low level of high-density lipoprotein (HDL)-cholesterol, a component of the atherogenic dyslipidaemia of the metabolic syndrome, has been shown to be an important determinant of coronary risk, which rises in prevalence with increasing age. Thus, raising HDLcholesterol, in addition to lowering the level of low-density lipoprotein (LDL)-cholesterol, seems a plausible approach to reduce cardiovascular risk in an ageing population. Clinical studies have shown that adding nicotinic acid, which raises HDL-cholesterol by 20-25%, to a statin enhances the reduction in progression of atherosclerosis. Results of the ongoing Atherothrombosis Intervention in Metabolic syndrome with low HDL/High triglyceride and Impact on Global Health Outcomes (AIM-HIGH) study are awaited with interest to see whether such theoretical benefit translates into clinical outcome.

Fenofibrate increases HDL-cholesterol by reducing cholesteryl ester transfer protein expression

In addition to efficiently decreasing VLDL-triglycerides (TGs), fenofibrate increases HDL-cholesterol levels in humans. We investigated whether the fenofibrate-induced increase in HDL-cholesterol is dependent on the expression of the cholesteryl ester transfer protein (CETP). To this end, APOE*3-Leiden (E3L) transgenic mice without and with the human CETP transgene, under the control of its natural regulatory flanking regions, were fed a Western-type diet with or without fenofibrate. Fenofibrate (0.04% in the diet) decreased plasma TG in E3L and E3L.CETP mice (-59% and -60%; P < 0.001), caused by a strong reduction in VLDL. Whereas fenofibrate did not affect HDL-cholesterol in E3L mice, fenofibrate dose-dependently increased HDL-cholesterol in E3L.CETP mice (up to +91%). Fenofibrate did not affect the turnover of HDL-cholesteryl ester (CE), indicating that fenofibrate causes a higher steady-state HDL-cholesterol level without altering the HDL-cholesterol flux through plasma. Analysis of the hepatic gene expression profile showed that fenofibrate did not differentially affect the main players in HDL metabolism in E3L.CETP mice compared with E3L mice. However, in E3L.CETP mice, fenofibrate reduced hepatic CETP mRNA (-72%; P < 0.01) as well as the CE transfer activity in plasma (-73%; P < 0.01). We conclude that fenofibrate increases HDL-cholesterol by reducing the CETP-dependent transfer of cholesterol from HDL to (V)LDL, as related to lower hepatic CETP expression and a reduced plasma (V)LDL pool.

Best practice in primary care pathology: review 7

This seventh best-practice review examines four series of common primary care questions in laboratory medicine: (1) blood count abnormalities 2; (2) cardiac troponins; (3) high-density lipoprotein cholesterol; and (4) viral diseases 2. The review is presented in a question-answer format, with authorship attributed for each question series. The recommendations are a précis of guidance found using a standardised literature search of national and international guidance notes, consensus statements, health policy documents and evidence-based medicine reviews, supplemented by Medline Embase searches to identify relevant primary research documents. The recommendations are not standards, but form a guide to be set in the clinical context. Most are consensus based rather than evidence based. They will be updated periodically to take account of new information.

Lipid-lowering effects of statins: a comparative review

The pharmacological regulation of lipid metabolism in patients with dyslipidaemia is unequivocally associated with significant reductions in risk for cardiovascular morbidity and mortality. There is strong clinical trial data to support of the use of statin therapies in the settings of both primary and secondary prevention. This paper addresses: i) the mechanisms of action of antilipidaemic medications; ii) dosing regimens and the pharmacokinetic differences among drugs of the same class; iii) risk for drug interactions; and iv) reviews the clinical trial evidence used to support the use of particular antilipidaemic medications in specific physiological settings.

[New insights and perspectives in the management of dyslipidemia]

PURPOSE

Recent end point trials of lipid-lowering drugs have shown that patients at very high-risk for coronary disease benefit from treatments that lowers low density lipoprotein cholesterol (LDL cholesterol) plasma levels< or =70 mg/dl and that patients with at least 2 risk factors benefit from LDL cholesterol levels< or =100 mg/dl. Epidemiologic studies have shown that the concentration of high density lipoprotein cholesterol (HDL cholesterol) is a strong, independent, inverse predictor of coronary disease risk. Innovative pharmacological approaches to raise low HDL cholesterol levels are currently of considerable interest, especially for patients with type 2 diabetes or metabolic syndrome.

RESULTS

Rosuvastatin has shown superior efficacy in lowering LDL cholesterol, although evidence of clinical benefit is actually lacking. Ezetimibe is a lipid-lowering drug that inhibits absorption of dietary and biliary cholesterol. Its co-administration with statin has given very interesting results. Niacin is the most effective of currently available options for raising HDL cholesterol, although tolerability can be an issue, with serious side effects such as loss of glucose control and liver toxicity. Flushing may occur in 80% of treated patients. Two CETP inhibitors have shown therapeutical efficacy to raise HDL cholesterol, but clinical benefit remains uncertain.

Clinical significance of recent lipid trials on reducing risk in patients with type 2 diabetes mellitus

Type 2 diabetes mellitus is a significant risk factor for cardiovascular disease and is associated with significant cardiovascular morbidity and mortality. Current guidelines suggest lifestyle modification and at least a 30%-40% reduction of low-density lipoprotein (LDL) cholesterol with drug therapy, to a target level of <100 mg/dL. Additional secondary therapeutic targets include increasing high-density lipoprotein (HDL) cholesterol and lowering triglycerides. Although the 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) remain first-line therapy, combination therapy with statins and fibrates or niacin is often needed to achieve target levels in patients with diabetes. Statins significantly lower LDL and decrease the relative risk for nonfatal myocardial infarction (MI) or coronary artery disease death. Clinical trials have demonstrated that in high-risk patients, such as those with diabetes, monotherapy with statins reduces overall cardiovascular events by 30%-40%. Fibrates have modest effects to lower LDL, but they significantly increase HDL and reduce triglycerides, they may improve glucose tolerance, and they have been shown to reduce nonfatal MI by 25%. Although data are limited, the combination of a statin and fenofibrate significantly reduced LDL, reduced triglycerides, and increased HDL compared with a statin alone. It is hoped that ongoing trials will demonstrate the clinical outcomes benefits of combination therapy in patients with diabetes.

Update on advances in atherothrombosis

The study of atherothrombosis is a rapidly evolving field, and significant progress was achieved in various aspects of the disease during the past year. In the area of diagnostic imaging, MRI and multidetector CT were actively used to evaluate the characteristics of the arterial wall, including calcified and noncalcified lesions, and both in the coronary and extracoronary vascular territories. There was also extensive research into the application of imaging modalities to visualize cellular or molecular disease processes, known as molecular imaging. Considerable efforts were devoted to the identification of novel biomarkers that reflect different components of atherothrombosis, namely inflammation, thrombogenicity, oxidative stress and reparative ability, predicting the presence of early disease or the risk of clinical events. In the therapeutic arena, substantial evidence accumulated on the beneficial effects of several pharmacologic agents, most significantly statins. Finally, important advances were also made in the understanding of the roles of immunity and neovascularization in atherogenesis, including the development and progression of disease at different stages. Awareness of these recent advances and new lines of active research is fundamental for health professionals involved in the care of patients with atherothrombosis. In this Review we present an overview of data in these areas.

High-Density Lipoprotein Cholesterol: A Potential Therapeutic Target for Prevention of Coronary Artery Disease

High-density lipoprotein cholesterol has an important role in the pathophysiology of coronary artery disease. High-density lipoprotein cholesterol is becoming an increasingly important prognostic and therapeutic target. The purpose of this paper is to review the biochemical pathways involved in reverse cholesterol transport and to discuss potential, clinically based high-density lipoprotein therapies that may contribute to reduction in risk of atherosclerosis.

Reducing cardiovascular risk by targeting high-density lipoprotein cholesterol

Although lowering low-density lipoprotein (LDL) cholesterol with statins can substantially reduce cardiovascular morbidity and mortality, many treated patients retain a residual risk for cardiovascular events. Low levels of high-density lipoprotein (HDL) cholesterol may underpin this residual risk and may represent an additional target for intervention. Several new therapies for substantially increasing HDL cholesterol levels are under investigation, including cholesteryl ester transfer protein (CETP) inhibitors, apolipoprotein A-I mimetics and recombinant HDL, liver X receptor (LXR) agonists, and peroxisome proliferator-activated receptor (PPAR) agonists. Combining new HDL cholesterol-elevating agents with existing LDL cholesterol-lowering agents may improve the cardiovascular risk reductions currently attainable.

Fibrates after the FIELD study: Some answers, more questions

Fibrates have a long history in cardiovascular disease. These drugs raise high-density lipoprotein (HDL)-cholesterol, reduce triglycerides and improve small dense low-density lipoprotein (LDL) so would be expected to have large effects in type 2 diabetes, where this is the typical lipid profile. The general trial results with these agents have been confusing, with varying cardiovascular benefits. The Fenofibrate Intervention and Endpoint Lowering in Diabetes (FIELD) study recruited a low-risk population with a lipid profile that would be more usually treated with a statin. FIELD showed a non-significant 11% reduction (p = 0.16) in the primary end point of coronary events and a significant 11% benefit on the secondary end point of cardiovascular events and procedures (p = 0.04). Most of the benefits were seen in primary prevention and non-fatal myocardial events. Fenofibrate had little effect on HDL-C; the effects of the trial are consistent with the LDL-C reducing potential of this drug. FIELD, because of unequal statin drop-in, gives little evidence on statin-fibrate combination therapy but does reinforce the available data on the safety of fenofibrate-statin combination therapy. In addition, fenofibrate showed possible benefits on microvascular disease end points, including albuminuria and retinopathy. On current data fenofibrate and gemfibrozil seem to be reasonable second-line agents in type 2 diabetes or secondary prevention with low HDL-C, respectively, based on outcome evidence. In combination therapy, drug-specific safety considerations will affect the exact choice of agent, especially in combination with statins, but the efficacy of combination therapy still requires validation in the Action to Control Cardiovascular Risk in Diabetes (ACCORD) study.

Rimonabant: endocannabinoid inhibition for the metabolic syndrome

Rimonabant is the first drug to target the endocannabinoid (CB) pathway by inhibiting the actions of anandamide and 2-archidonyl-glycerol on CB1 receptors. This review gives an overview of rimonabant and the CB system and how this system relates to obesity. Rimonabant blocks the central effects of this neurotransmitter pathway involved in obesity and weight control and also blocks the direct effects of CBs on adipocyte and hepatocyte metabolism. Blockade of CB1 receptors leads to a decrease in appetite and also has direct actions in adipose tissue and the liver to improve glucose, fat and cholesterol metabolism so improving insulin resistance, triglycerides and high-density lipoprotein cholesterol (HDL-C) and in some patients, blood pressure. The Rimonabant in Obesity (RIO) trials have shown that rimonabant induces weight loss > 5% in 30-40% of patients and > 10% in 10-20% above both a dietary run-in and long-term hypocaloric management over a 2 year period with a low level of drug-related side effects. Rimonabant therapy is associated with an extra 8-10% increase in HDL-C and a 10-30% reduction in triglycerides and improvements in insulin resistance, glycaemic control in patients with diabetes and also adipokines and cytokines including C-reactive protein over hypocaloric diet therapy. In addition rimonabant abolishes the weight gain associated with smoking cessation and improves the chances of quitting smoking. Thus rimonabant has major effects on both the metabolic syndrome and cardiovascular risk factors thus has the potential to reduce the risks of type 2 diabetes and cardiovascular disease associated with the cardiometabolic phenotype.

Effects of fenofibrate and simvastatin on HDL-related biomarkers in low-HDL patients

The objective of the present study was to compare the effects of fenofibrate versus simvastatin on various HDL-related biomarkers in dyslipidemic patients with low HDL-C, in whom it is as yet unclear whether a statin or a fibrate is the most appropriate treatment. Fifty-two patients received either fenofibrate (160 mg/day) or simvastatin (40 mg/day) for 8 weeks in a randomized, double-blind, parallel group trial. Simvastatin effectively lowered plasma LDL-C and apoB levels, but did not change plasma HDL levels and HDL-related biomarkers, except for a small, significant increase in the capacity of plasma to promote SR-BI mediated cholesterol efflux. Fenofibrate did not affect plasma LDL-C levels but lowered triglycerides, and exerted a remarkable HDL-C raising activity (+22%), with patients in the lowest range of HDL-C getting the maximal benefit. The HDL-C raise was associated with a shift of HDL from large to small particles, and from LpA-I to LpA-I:A-II, which might explain the observed increase in the plasma capacity to promote ABCA1 mediated efflux with no changes in SR-BI efflux. The distinct and complementary effects of fenofibrate and simvastatin on lipid parameters and HDL-related biomarkers suggest that a combination therapy with the two drugs in dyslipidemic patients with low HDL would be fully justified.

Functionally defective high-density lipoprotein: a new therapeutic target at the crossroads of dyslipidemia, inflammation, and atherosclerosis

High-density lipoproteins (HDL) possess key atheroprotective biological properties, including cellular cholesterol efflux capacity, and anti-oxidative and anti-inflammatory activities. Plasma HDL particles are highly heterogeneous in physicochemical properties, metabolism, and biological activity. Within the circulating HDL particle population, small, dense HDL particles display elevated cellular cholesterol efflux capacity, afford potent protection of atherogenic low-density lipoprotein against oxidative stress and attenuate inflammation. The antiatherogenic properties of HDL can, however be compromised in metabolic diseases associated with accelerated atherosclerosis. Indeed, metabolic syndrome and type 2 diabetes are characterized not only by elevated cardiovascular risk and by low HDL-cholesterol (HDL-C) levels but also by defective HDL function. Functional HDL deficiency is intimately associated with alterations in intravascular HDL metabolism and structure. Indeed, formation of HDL particles with attenuated antiatherogenic activity is mechanistically related to core lipid enrichment in triglycerides and cholesteryl ester depletion, altered apolipoprotein A-I (apoA-I) conformation, replacement of apoA-I by serum amyloid A, and covalent modification of HDL protein components by oxidation and glycation. Deficient HDL function and subnormal HDL-C levels may act synergistically to accelerate atherosclerosis in metabolic disease. Therapeutic normalization of attenuated antiatherogenic HDL function in terms of both particle number and quality of HDL particles is the target of innovative pharmacological approaches to HDL raising, including inhibition of cholesteryl ester transfer protein, enhanced lipidation of apoA-I with nicotinic acid and infusion of reconstituted HDL or apoA-I mimetics. A preferential increase in circulating concentrations of HDL particles possessing normalized antiatherogenic activity is therefore a promising therapeutic strategy for the treatment of common metabolic diseases featuring dyslipidemia, inflammation, and premature atherosclerosis.

Micronized fenofibrate: a useful choice for the correction of dyslipidemia in metabolic syndrome and Type 2 diabetes

Cardiovascular disease is the principal cause of illness and disability in patients with diabetes, and is also the most common cause of death worldwide in adults. Fenofibrate, a member of the fibrate class of lipid-modifying drugs, is a potent triglyceride-lowering and high-density lipoprotein cholesterol-raising agent and has a variable effect on low-density lipoprotein cholesterol. Fenofibrate administration also leads to a modified, less atherogenic low-density lipoprotein profile, with a consistent effect toward increased low-density lipoprotein particle size and a reduction in the low-density lipoprotein particle density. Maximal clinical efficacy in fibrates has been demonstrated in subjects with dyslipidemia, particularly in populations with features of the metabolic syndrome and in patients with Type 2 diabetes. Angiographic data from the Diabetes Atherosclerosis Intervention Study (DAIS) support a similar effect of fenofibrate. However, in the recent Fenofibrate Intervention and Event Lowering in Diabetes trial (FIELD; 9795 patients with Type 2 diabetes), the rate of nonfatal macrovascular events, after adjustment for the use of other lipid-lowering agents and significant reductions in microvascular complications, was lower for the fenofibrate treatment group. These results and those from a current large trial, ACtion to COntrol cardiovascular Risk in Diabetes (ACCORD), will provide valuable evidence for the likely future use of this drug in combination with statins for reducing cardiovascular disease risk in the metabolic syndrome and in Type 2 diabetes.

Favourable impact of low-calorie cranberry juice consumption on plasma HDL-cholesterol concentrations in men

A low HDL-cholesterol concentration is an independent risk factor for CVD. Studies have suggested that flavonoid consumption may be cardioprotective, and a favourable impact on circulating HDL-cholesterol concentrations has been suggested to partially explain this association. The aim of the present study was to determine the effect of consuming increasing daily doses of low-calorie cranberry juice cocktail (CJC) on the plasma lipid profile of abdominally obese men. For that purpose, thirty men (mean age 51 (SD 10) years) consumed increasing doses of CJC during three successive periods of 4 weeks (125 ml/d, 250 ml/d, 500 ml/d). Before the study and after each phase, we measured changes in physical and metabolic variables. We noted a significant increase in plasma HDL-cholesterol concentration after the consumption of 250 ml CJC/d (+8.6+/-14.0% v. 0 ml CJC/d; P<0.01), an effect that plateaued during the last phase of the study (500 ml CJC/d: +8.1+/-10.0% v. 0 ml CJC/d; P<0.0001). Multivariate analyses revealed that changes in plasma apo A-I (R(2)=48%, P<0.0001) and triacylglycerol (R(2)=16%, P<0.005) concentrations were the only variables significantly contributing to the variation in plasma HDL-cholesterol concentration noted in response to the intervention. No variation was observed in total as well as in LDL and VLDL cholesterol. The present results show that daily CJC consumption is associated with an increase in plasma HDL-cholesterol concentrations in abdominally obese men. We hypothesise that polyphenolic compounds from cranberries may be responsible for this effect, supporting the notion that the consumption of flavonoid-rich foods can be cardioprotective.

Atherogenic dyslipidemia in metabolic syndrome and type 2 diabetes: therapeutic options beyond statins

Lowering of low-density lipoprotein cholesterol with 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) is clearly efficacious in the treatment and prevention of coronary artery disease. However, despite increasing use of statins, a significant number of coronary events still occur and many of such events take place in patients presenting with type 2 diabetes and metabolic syndrome. More and more attention is being paid now to combined atherogenic dyslipidemia which typically presents in patients with type 2 diabetes and metabolic syndrome. This mixed dyslipidemia (or "lipid quartet"): hypertriglyceridemia, low high-density lipoprotein cholesterol levels, a preponderance of small, dense low-density lipoprotein particles and an accumulation of cholesterol-rich remnant particles (e.g. high levels of apolipoprotein B) – emerged as the greatest "competitor" of low-density lipoprotein-cholesterol among lipid risk factors for cardiovascular disease. Most recent extensions of the fibrates trials (BIP – Bezafibrate Infarction Prevention study, HHS – Helsinki Heart Study, VAHIT – Veterans Affairs High-density lipoprotein cholesterol Intervention Trial and FIELD – Fenofibrate Intervention and Event Lowering in Diabetes) give further support to the hypothesis that patients with insulin-resistant syndromes such as diabetes and/or metabolic syndrome might be the ones to derive the most benefit from therapy with fibrates. However, different fibrates may have a somewhat different spectrum of effects. Other lipid-modifying strategies included using of niacin, ezetimibe, bile acid sequestrants and cholesteryl ester transfer protein inhibition. In addition, bezafibrate as pan-peroxisome proliferator activated receptor activator has clearly demonstrated beneficial pleiotropic effects related to glucose metabolism and insulin sensitivity. Because fibrates, niacin, ezetimibe and statins each regulate serum lipids by different mechanisms, combination therapy – selected on the basis of their safety and effectiveness – may offer particularly desirable benefits in patients with combined hyperlipidemia as compared with statins monotherapy.

Reducing residual cardiovascular risk: the relevance of raising high-density lipoprotein cholesterol in patients on cholesterol-lowering treatment

Reducing low-density lipoprotein cholesterol (LDL-C) with statin therapy represents the cornerstone of dyslipidaemia management in patients with cardiovascular disease, as reflected in current treatment guidelines. Yet even among statin-treated patients who achieve LDL-C targets (< 2.59 mmol/L [100 mg/dL]), the residual risk of further cardiovascular events remains unacceptably high. Although clinical studies indicate that intensive LDL-C lowering may provide some additional benefit, this does not suppress the excess cardiovascular risk sufficiently. This European Expert Panel therefore recognises that there is an unmet clinical need in the management of these patients. Additional intervention to modify other clinically important risk factors should be viewed as a priority.

A reduced level of high-density lipoprotein cholesterol (HDL-C) < 1.03 mmol/L (40 mg/dL) in men and < 1.29 mmol/L (50 mg/dL) in women is an important independent predictive factor for coronary heart disease. HDL-C levels are also predictive of cardiovascular risk in statin-treated patients, irrespective of their LDL-C levels. Therefore, HDL-C represents a logical therapeutic target for reducing cardiovascular risk further in statin-treated patients, including those who achieve LDL-C targets. Given that low HDL-C is common among dyslipidaemic patients with cardiovascular disease, a therapeutic strategy aimed at effectively raising HDL-C, while at the same time lowering LDL-C to target levels, would be expected to offer clinical benefit beyond that achieved through LDL-C reduction alone. Although both nicotinic acid and fibrates raise HDL-C, nicotinic acid has greater potency. Studies show that combination therapy with prolonged-release (PR) nicotinic acid and a statin has an acceptable tolerability profile, normalises an atherogenic lipoprotein profile, and is able to induce regression of atherosclerosis and reduce coronary risk in patients with established cardiovascular disease and suboptimal HDL-C levels.

In conclusion, this European Expert Panel recommends that combination therapy with a statin and an HDL-C raising agent, such as PR nicotinic acid, should be considered in these patients, who remain at high residual risk despite achieving target LDL-C levels with statin monotherapy. Ongoing studies are essential to confirm the clinical outcome benefits of this approach.

Combination of fenofibrate plus low-dose nicotinic acid added to statin treatment in type 2 diabetes: An open-label, crossover study

BACKGROUND

Plasma lipid abnormalities commonly persist in patients with diabetic dyslipidemia in spite of statin monotherapy.

OBJECTIVE

The aim of this study was to determine whether fenofibrate plus low-dose nicotinic acid adequately improves the lipoprotein profile in patients with diabetic dyslipidemia who are being treated with a statin.

METHODS

In this open-label, crossover study, patients with type 2 diabetes mellitus who were receiving statin treatment were enrolled at the Lipid Clinic of the Veterans Affairs Medical Center, Dallas, Texas, and administered simvastatin 20 mg/d for 8 weeks. At the end of the 8-week period, fenofibrate 160 mg/d was added for 8 weeks, followed by the addition of extended-release nicotinic acid 1 g/d for an additional 8 weeks. The first subject was recruited on September 25, 2003, and the last subject was recruited on September 28, 2004. Liver function tests, creatine phosphokinase activity, and blood glucose levels were assessed every 4 weeks to assess tolerability. Levels of fasting plasma lipids and lipoprotein cholesterol were measured every 8 weeks on 3 consecutive days in each patient; C-reactive protein, lipoprotein pattern, and glycosylated hemoglobin levels were assessed once every 8 weeks. Plasma levels of total cholesterol, triglycerides, very-low-density lipoprotein plus intermediate-density lipoprotein cholesterol (VLDL+IDL-C), low-density lipoprotein cholesterol, high-density lipoprotein cholesterol (HDL-C), and apolipoprotein B were also measured.

RESULTS

Twenty-six patients were enrolled in the study and 20 patients (18 men, 2 women; mean [SD] age, 58.8 [6.5] years) completed it. The mean plasma triglyceride level was significantly decreased (-29.2%; P= 0.004) and the mean HDL-C level was significantly increased (+13.5%; P < 0.001) with 3-drug treatment (simvastatin + fenofibrate + extended-release nicotinic acid) compared with simvastatin monotherapy. Significant reductions in plasma levels of VLDL+IDL-C (-35.7%; P = 0.001), VLDL+IDL-apolipoprotein B (-30%; P = 0.005), non-HDL-C (-12.9%; P = 0.001), and total-apolipoprotein B (-17.9%; P < 0.001) were seen with the 3-drug treatment compared with simvastatin alone. Compared with simvastatin monotherapy, simvastatin + fenofibrate-treated (2-drug treatment) patients had significantly lower plasma levels of triglycerides (-24.9%; P = 0.014) and significantly higher levels of HDL-C (+5.4%; P = 0.008). Significant reductions were also seen in levels of VLDL+IDL-C (-28.6%; P = 0.004), VLDL+IDL-apolipoprotein B (-26.7%; P < 0.001), non-HDL-C (-9.1 %; P= 0.004), and total-apolipoprotein B (-12.3%; P < 0.001) in the 2-drug treatment group compared with the simvastatin monotherapy group. The administration of 3-drug treatment was associated with improved responses in all lipoprotein fractions, although only the increase in HDL-C level was statistically significant (+7.7%; P = 0.008) compared with 2-drug treatment.

CONCLUSIONS

Treatment with the 3-drug regimen was associated with a significant reduction in triglyceride levels compared with simvastatin monotherapy. However, there was not a significant incremental reduction in triglyceride levels when nicotinic acid was added to the 2-drug treatment, suggesting that the triglyceride-lowering effect of fenofibrate + nicotinic acid is not cumulative. To obtain clinically meaningful responses, particularly for the treatment of elevated HDL-C, higher doses of nicotinic acid might be required.

Historical milestones in measurement of HDL-cholesterol: Impact on clinical and laboratory practice

High-density lipoprotein cholesterol (HDL-C) comprises a family of particles with differing physicochemical characteristics. Continuing progress in improving HDL-C analysis has originated from two separate fields-one clinical, reflecting increased attention to HDL-C in estimating risk for coronary heart disease (CHD), and the other analytical, reflecting increased emphasis on finding more reliable and cost-effective HDL-C assays. Epidemiologic and prospective studies established the inverse association of HDL-C with CHD risk, a relationship that is consistent with protective mechanisms demonstrated in basic research and animal studies. Atheroprotective and less atheroprotective HDL subpopulations have been described. Guidelines on primary and secondary CHD prevention, which increased the workload in clinical laboratories, have led to a revolution in HDL-C assay technology. Many analytical techniques including ultracentrifugation, electrophoresis, chromatography, and polyanion precipitation methods have been developed to separate and quantify HDL-C and HDL subclasses. More recently developed homogeneous assays enable direct measurement of HDL-C on an automated analyzer, without the need for manual pretreatment to separate non-HDL. Although homogeneous assays show improved accuracy and precision in normal serum, discrepant results exist in samples with atypical lipoprotein characteristics. Hypertriglyceridemia and monoclonal paraproteins are important interfering factors. A novel approach is nuclear magnetic resonance spectroscopy that allows rapid and reliable analysis of lipoprotein subclasses, which may improve the identification of individuals at increased CHD risk. Apolipoprotein A-I, the major protein of HDL, has been proposed as an alternative cardioprotective marker avoiding the analytical limitations of HDL-C.

Antiatherogenic small, dense HDL--guardian angel of the arterial wall?

Our understanding of the relationship between the atheroprotective activities of HDL and heterogeneity of HDL particles has advanced greatly. HDL particles are highly heterogeneous in structure, intravascular metabolism and antiatherogenic activity. In this review, we discuss new findings on the antiatherogenic properties of HDL particles. Small, dense HDL possesses potent antioxidative activity but this is compromised under conditions of atherogenic dyslipidemia. HDL functional deficiency frequently coincides with reductions in HDL-cholesterol concentration and alterations in HDL metabolism and structure. Formation of small, dense HDL particles with attenuated antiatherogenic activity can be mechanistically related to HDL enrichment in triglycerides and in serum amyloid A, depletion of cholesteryl esters, covalent modification of HDL apolipoproteins and attenuated antiatherogenic function of apolipoprotein AI. Low circulating levels of HDL cholesterol might, therefore, be associated with the defective functionality of small HDL particles of abnormal structure and composition. In common metabolic diseases, such as type 2 diabetes and metabolic syndrome, deficiency of HDL particle number and function favor accelerated atherosclerosis. Therapeutic normalization of the quantity, quality and biological activities of HDL particles thus represents a novel approach to attenuating atherosclerosis in dyslipidemic individuals with metabolic disease. Cholesteryl ester transfer protein inhibitors, nicotinic acid, reconstituted HDL and other HDL-raising agents are being investigated. Induction of selective increase in the circulating concentrations of small, dense HDL3 particles with increased antiatherogenic activity seems especially promising, particularly for therapy of atherogenic dyslipidemia.

LDL-cholesterol lowering or HDL-cholesterol raising for cardiovascular prevention

A number of reports have indicated that both lowering low density lipoprotein (LDL)-cholesterol and raising high density lipoprotein (HDL)-cholesterol can result in significant cardiovascular benefit, both in terms of reduction of events and also, to a variable extent, of atheromatous lesions. LDL and HDL have opposite roles in body cholesterol regulation and, in theory, both reduced deposition (LDL reduction) and increased removal (raised HDL) can improve vascular disease. A number of reports over the last 30 years have attempted to quantitate with cholesterol balance/turnover studies, the correlations between LDL and HDL levels and body cholesterol pool sizes. More recently, these studies have evaluated the effects of LDL or HDL changes on cholesterol elimination. Data have, at times, been fully consistent with theoretical expectations, whereas at others they have not. Evaluation of these, at times, historical data provides, however, an important clue to the understanding of current results with different medications for the management of lipoprotein disorders.

FIELDS of dreams, fields of tears: a perspective on the fibrate trials

Endpoint studies have been performed with fibrates in coronary heart disease since 1971. The results have been confusing - starting with initial benefits in small studies, but contradicted by either minimal benefits in the Coronary Drug Project or adverse noncardiovascular (non-CV) effects in the World Health Organization Clofibrate Study. Fibrates returned for patients with low HDL-C and low LDL-C after a 25% event reduction were seen in the Veterans Affairs HDL Intervention Trial. The greater prominence ascribed to the lipid triad of the metabolic syndrome and the increasing prevalence of diabetes increased the topicality of fibrates given their main action of converting small dense to light buoyant LDL. The Fenofibrate Intervention in Event Lowering in Diabetes (FIELD) Study has carried on the tradition. Fenofibrate therapy in 9795 patients comprising a mixed low-risk primary and a medium-risk secondary prevention cohort resulted in an 11% reduction in coronary events (p = 0.16), a similar but significant reduction in CV events (p = 0.04; number needed to treat = 70). The benefits were concentrated in primary prevention and on nonfatal myocardial events, but the study was confounded by asymmetrical statin drop-in due to the LDL-C-lowering effect of fenofibrate. Safety was generally good, including in combination with statins, but old concerns about sudden death, pancreatitis and venous thrombosis returned. Unexpected benefits were seen with fenofibrate on microvascular endpoints including microalbuminuria and retinopathy. Fenofibrate is a reasonable second-line therapy for dyslipidaemia in diabetes and safe in combination therapy. Its benefits on microvascular disease and in combination therapy require further confirmation.

The Changing Face of Dyslipidemia Therapies

To date, the major emphasis of dyslipidemia management has focused on the reduction of serum low-density lipoprotein cholesterol (LDL-C) levels, which several robust trials show significantly decreases the risk of coronory heart disease (CHD). To achieve goal LDL-C levels will require that some individuals take more than 1 cholesterol-lowering medication. In addition, many dyslipidemic patients also have concomitant risk factors for cardiovascular disease including hypertension, elevated plasma glucose, and high body mass index, requiring additional therapies. In addition to drugs that lower LDL-C, several agents under investigation are targeting other markers for decreasing the risk of atherosclerotic disease. Some of these agents target the reduction of C-reactive protein with a more potent statin, increased high-density lipoprotein cholesterol (HDL-C) with the cholesterol ester transfer protein inhibitor, inhibition of triglyceride or very-low-density lipoprotein cholesterol (VLDL-C) with the acyl coenzyme A: cholesterol acyltransferase inhibitor, reduction of VLDL-C with microsomal triglyceride transfer protein inhibitor, change in percentage coronary atheroma volume with HDL-C mimetics, and the reduction of bile acid transport and reabsorption with the ileal bile acid transport inhibitors. This review will provide an overview of the existing landscape for the medical treatment of dyslipidemia, including available therapies and future trends.

Therapeutic elevation of HDL-cholesterol to prevent atherosclerosis and coronary heart disease

Innovative pharmacological approaches to raise anti-atherogenic high-density lipoprotein-cholesterol (HDL-C) are currently of considerable interest, particularly in atherogenic dyslipidemias characterized by low levels of HDL-C, such as type 2 diabetes, the metabolic syndrome, and mixed dyslipidemia, but equally among individuals with or at elevated risk for premature cardiovascular disease (CVD). Epidemiological and observational studies first demonstrated that HDL-C was a strong, independent predictor of coronary heart disease (CHD) risk, and suggested that raising HDL-C levels might afford clinical benefit. Accumulating data from clinical trials of pharmacological agents that raise HDL-C levels have supported this concept. In addition to the pivotal role that HDL-C plays in reverse cholesterol transport and cellular cholesterol efflux, HDL particles possess a spectrum of anti-inflammatory, anti-oxidative, anti-apoptotic, anti-thrombotic, vasodilatory and anti-infectious properties, all of which potentially contribute to their atheroprotective nature. Significantly, anti-atherogenic properties of HDL particles are attenuated in common metabolic diseases that are characterized by subnormal HDL-C levels, such as type 2 diabetes and metabolic syndrome. Inhibition of cholesteryl ester transfer protein (CETP), a key player in cholesterol metabolism and transport, constitutes an innovative target for HDL-C raising. In lipid efficacy trials, 2 CETP inhibitors-JTT-705 and torcetrapib-induced marked elevation in HDL-C levels, with torcetrapib displaying greater efficacy. Moreover, both agents attenuate aortic atherosclerosis in cholesterol-fed rabbits. Clinical trial data demonstrating the clinical benefits of these drugs on atherosclerosis and CHD are eagerly awaited.

Effects of combined dietary supplementation on oxidative and inflammatory status in dyslipidemic subjects

BACKGROUND AND AIM

Dyslipidemia is one of the main risk factors for atherosclerosis, usually the underlying cause of cardiovascular diseases which are the major cause of morbidity and mortality in developed countries. The aim of this study was to assess the effects and the advantages of a combined dietary supplementation with PUFA n-3, vitamin E, niacin and gamma-oryzanol on lipid profile, inflammatory status and oxidative balance.

METHODS AND RESULTS

Fifty-seven dyslipidemic volunteers were randomly assigned to receive: placebo (group A, 19 subjects); PUFA n-3 and vitamin E (group B, 18 subjects); the same as B plus gamma-oryzanol and niacin (group C, 20 subjects). Lipid profile, reactive oxygen species (ROS), total antioxidant capacity (TAC), vitamin E, interleukin 1-beta (IL1-beta), tumor necrosis factor (TNF-alpha) and thromboxane B2 (TXB2) were determined at baseline (T0) and after four months (T1). All dyslipidemic subjects showed, at baseline, oxidative stress and, after four months, all biochemical markers improved significantly in groups treated with dietary supplementation. Particularly in group C all lipid patterns improved significantly.

CONCLUSIONS

Our findings demonstrate that the strategy of combining different compounds, which protect each other and act together at different levels of the lipid chain production, improves lipid profile, inflammatory and oxidative status, allowing us to reduce the dose of each compound under the threshold of its side effects.

Therapeutic use of the high-density lipoprotein protein and peptides

High-density lipoprotein (HDL) therapy is a novel and emerging area of therapeutic development in the cardiovascular field. It attempts to supplement and improve the vascular benefit exerted by other agents that are active on lipid metabolism, for example, hypolipidaemic drugs. Furthermore, it takes advantage of the novel techniques of coronary evaluation. A number of reports have examined the potential therapeutic properties of the synthetic HDLs prepared by complexing recombinant apolipoprotein (apo) A-I(Milano), a variant form of native apoA-I, with phospholipids. The availability of synthetic HDL complexes containing recombinant apoA-I(Milano) has opened up a new era of therapeutic management for coronary disease. HDL formulations of recombinant apoA-I(Milano)-phospholipid complexes have clearly shown rapid regression of a focal carotid atheroma as well as powerful protection from myocardial infarction in a rabbit model. In a pilot study, ETC-216 showed a significant reduction in coronary plaque burden after five weekly treatments, assessed by intravascular ultrasound in patients with acute coronary syndrome. Other therapeutic options of HDL therapy have recently became available.

Strategies for Modifying High-Density Lipoprotein Cholesterol: A Role for Nicotinic Acid

Statin-mediated lowering of low-density lipoprotein cholesterol (LDL-C) is regarded as the foundation of lipid-modifying therapy. However, the residual cardiovascular risk for statin-treated patients remains high, indicating the need for therapeutic intervention against other lipid targets as well as non-lipid risk factors. Low levels of high-density lipoprotein cholesterol (HDL-C) are established as a strong independent risk factor for cardiovascular disease. Intervention studies have also demonstrated clinical benefits associated with HDL-C raising. Although lifestyle modification does play an important role in raising HDL-C, most patients with a low HDL-C and at high risk of coronary events also require pharmacological treatment to achieve the target. Of the available treatment options, nicotinic acid is the most potent agent for raising HDL-C (by 26% at clinically recommended doses), while substantially lowering triglycerides and LDL-C. The addition of nicotinic acid to primary statin therapy is a logical approach to dyslipidaemia management, given their complementary mechanism of action, and is supported by recent clinical trials such as the Arterial Biology for the Investigation of the Treatment Effects of Reducing cholesterol (ARBITER) 2 study. Raising HDL-C will increasingly become an important secondary focus of dyslipidaemia management.

Controversies in stable coronary artery disease

Coronary heart disease is still highly prevalent worldwide, and stable angina pectoris is one of its more common presentations. Three major controversies are risk factor management, drug therapy, and intervention. As well as the major risk factors stated by the Framingham study and European guidelines, other factors include abdominal obesity, metabolic syndrome, and psychological stress. How should these additional factors be rated? With respect to drug therapy, apart from aspirin, all patients with stable angina should be assessed for statin treatment. Although statins will reduce coronary events by about one third in patients with vascular disease, the absolute benefit depends on the absolute risk. Non-controversially, all patients should be considered for angiotensin-converting-enzyme inhibitors. The concept that beta blockers are protective from future coronary events can be disputed. Percutaneous coronary intervention can relieve symptoms without extending lifespan beyond medical therapy. However, strong mortality data favour coronary-artery bypass grafting in individuals with triple-vessel or even double-vessel disease. Thus, effort angina needs comprehensive assessment, lifestyle changes, and treatment tailored to the individual patient.

Syndrome métabolique : quelle définition pour quel(s) traitement(s) ?

Metabolic syndrome is asymptomatic and results from the increasing prevalence of obesity. Although several definitions exist and complicate its diagnosis, metabolic syndrome is characterized by the clustering of moderate troubles of glucose, lipid metabolism, body weight, hypertension and vascular inflammation ; the synergy between 3 of them triggers type 2 diabetes, atherosclerosis and associated clinical events. Whatever the age but particularly in adolescence, the prevalence of metabolic syndrome is high ; beyond lifestyle interventions, the available treatments address essentially a single risk factor and an unmet medical need persists. The reduction of cardiovascular events in secondary prevention has been demonstrated for some antidiabetic, hypolipidemic and antihypertensive agents but any difference in efficacy between populations with and without metabolic syndrome has yet to be established. The approval of metabolic syndrome as a specific therapeutic target would need the characterization of its pathogenic mechanism, a clearer guidance for definition and diagnosis, and the clinical proof of concept of a novel molecule displaying multifactorial impacts. Some new mechanistic approaches are discussed and may represent a breakthrough particularly if positive results of Field and Proactive clinical studies related to PPARs are disclosed soon.

HDL-raising strategies in the treatment of coronary artery disease: perspectives from the Armed Forces Regression Study

PURPOSE OF REVIEW

Even with the aggressive reduction of LDL-cholesterol, the risk of cardiovascular events in patients with coronary artery disease remains substantial. The Armed Forces Regression Study was a randomized, double-blind, placebo-controlled trial of combination drug therapy aimed at raising HDL-cholesterol in patients with angiographically evident coronary artery disease. Drug therapy ultimately resulted in regression of the angiographic lesions and a reduction in cardiovascular events. This review places the Armed Forces Regression Study within the context of other recent studies.

RECENT FINDINGS

In the past few years a number of other important papers have further defined the important role HDL-cholesterol plays in the pathobiology of atherosclerosis. These studies have focused on three general areas: HDL-cholesterol metabolism and the reverse cholesterol transport pathway; novel therapeutic interventions and their effects on coronary artery disease as assessed through non-invasive imaging modalities; and finally a re-analysis of previous outcomes trials with established HDL-cholesterol modifying agents.

SUMMARY

The results of the Armed Forces Regression Study fit nicely within the evolving paradigm of targeting HDL-cholesterol in patients at risk of cardiovascular events. The use of niacin and well-tolerated fibrates as an adjunct to statins or as primary therapy in patients intolerant of statins appears reasonable in patients with low levels of HDL-cholesterol and at high risk of cardiovascular events. The further development of novel therapeutic approaches, in addition to broadening our pharmacological armamentarium, should further advance our understanding of HDL-cholesterol.