Effect of atorvastatin on high density lipoprotein cholesterol and its relationship with coronary events: a subgroup analysis of the GREek Atorvastatin and Coronary-heart-disease Evaluation (GREACE) Study

Physiological and psychological effects of a 12-week home-based telemonitored training in metabolic syndrome

Background

Metabolic Syndrome (MetS) increases the risk of cardiovascular diseases (CVD) and affects around one fourth of the population worldwide. In the prevention and treatment regular exercise trainings are inevitable. Providing personal supervision in out/inpatient care settings for such a large target population challenges the healthcare systems, but using telemonitoring of the home-performed trainings could be a promising and widely available option.

Objectives

The aim of this study was to evaluate the physiological and psychological effects of a 12-week home-based physical training program, telemonitored by widely available fitness devices on parameters of MetS patients.

Methods

A total of 55 MetS patients (mean age 49.19 ± 7.93 years) were involved in the study. They were asked to perform 3-5 sessions of exercise activity (min. 150 min) each week for 12 weeks. Trainings were monitored off-line by heart rate sensors, a fitness application and a cloud-based data transfer system. Physiotherapists supervised, coached, and feedback the trainings through an online coach system. We investigated different anthropometric parameters, maximum exercise and functional capacity levels, laboratory parameters, the level of depression, insomnia, vital exhaustion, and wellbeing as well.

Results

The average weekly training time was 152.0 ± 116.2 min. Out of the 55 participants who completed the program, 22 patients (40%) performed the recommended 150 min or more weekly. Patients showed statistically significant changes in: all the measured waist and hip circumferences; 6-min walk distance (6MWD; from 539.69 ± 78.62 to 569.72 ± 79.96 m, p < 0.001); maximal exercise capacity (11.02 ± 2.6 to 12.14 ± 2 MET, p < 0.001), stress-electrocardiogram duration time (13.74 ± 3.29 to 15.66 ± 2.64 min, p < 0.001); body weight (98.72 ± 21.7 to 97.45 ± 21.76 kg, p = 0.004); high-density lipoprotein cholesterol (n = 45, 1.28 ± 0.31 to 1.68 ± 0.36 mmol/L, p < 0.001); fasting plasma glucose (FPG; n = 47, 6.16 ± 1.26 to 5.44 ± 1.31 mmol/L, p = 0.001); glycated hemoglobin A1c (HbA1c; n = 41, 6.22 ± 0.68 to 5.87 ± 0.78%, p = 0.01). Out of the 55 patients who finished the program 38 patients (70%) completed all the psychological questionnaires. We found statistically significant decrease of the overall scores of the Maastricht Vital Exhaustion Questionnaire, from 3.37 ± 2.97 points to 2.63 ± 2.70 points (p < 0.05) and a significant increase of the overall scores of the WHO Wellbeing Scale from 9.92 ± 2.59 points to 10.61 ± 2.76 points (p < 0.05). We have not found any statistically significant changes in the scores of the Beck Depression Inventory and the Athens Insomnia Scale.

Conclusion

A 12-week home-based telemonitored training supported by an affordable, commonly available device system produces positive, statistically significant changes in many core components in MetS patients. Telemonitoring is a cheap method for coaching and feeding back the home-based interventions.

Development and Validation of an RP-HPLC Method for Determination of Atorvastatin and its Hydroxyl Metabolites in Human Plasma

Background:

Atorvastatin (AT) belongs to cholesterol-lowering agents, commonly used in patients with an increased risk of cardiovascular disease. The drug, as well as its hydroxyl metabolites, exhibit pharmacological activity, and their plasma levels may be helpful in the assessment of the therapeutic effectiveness.

Objective:

Development and validation of a fast and reproducible RP-HPLC method with UV detection for the simultaneous determination of atorvastatin and its active metabolites, para-hydroxy-atorvastatin (p-OH-AT) and ortho-hydroxy-atorvastatin (o-OH-AT) in human plasma.

Methods:

Optimal conditions of chromatographic separation of the analytes, as well as rosuvastatin, chosen as an internal standard, were studied. The absorbance of the compounds was measured at λ=248 nm. Validation of the method was performed. The usefulness of the method was confirmed for determination of the analytes in plasma of patients treated with the drug.

Results:

Total peak separation was achieved at LiChrospher 100 RP-18 column with a mobile phase composed of methanol and water (1:1,v:v) and a flow rate of 1.2 ml/min. The method was linear in the ranges of 0.025 - 1.0 μg/ml for AT, o-OH-AT and p-OH-AT. Intra- and inter-assay precision expressed as relative standard deviation was ≤13% for AT, ≤12% for p-OH-AT and ≤11% for o-OH-AT. Intraand inter-day accuracy of the method, expressed as a relative error, was ≤15%.

Conclusion:

The elaborated HPLC method is specific, repeatable, reproducible, adequately accurate and precise and fulfills the validation requirements for the bioanalytical method. The method was successfully applied for analysis of atorvastatin and its o-hydroxy metabolite in plasma of patients treated with the drug.

HDL and cardiovascular disease

High-density lipoprotein (HDL) has received increasing interest due to observations of an inverse relationship between its systemic levels and cardiovascular risk and targeted interventions in animal models that have had favourable effects on atherosclerotic plaque. In addition to its pivotal role in reverse cholesterol transport, HDL has been reported to possess a range of functional properties, which may exert a protective influence on inflammation, oxidation, angiogenesis and glucose homeostasis. This has led to the development of a range of HDL targeted therapeutics, which have undergone evaluation in clinical trials. The current state of HDL in cardiovascular prevention will be reviewed.

Infusional high-density lipoproteins therapies as a novel strategy for treating atherosclerosis

High-density lipoproteins (HDL) have received considerable interest as a target for the development of novel anti-atherosclerotic agents beyond conventional approaches to lipid lowering. While a number of approaches have focused on modifying remodeling and expression pathways implicated in the regulation of HDL levels, an additional approach involves simply infusions of delipidated HDL. Several groups have advanced HDL infusions to clinical development with intriguing signs suggesting potentially favorable impacts at the level of the artery wall. The findings of early studies of infusional HDL therapies will be reviewed.

Inducing apolipoprotein A-I synthesis to reduce cardiovascular risk: from ASSERT to SUSTAIN and beyond

Increasing attention has focused on efforts to promote the biological activities of high-density lipoproteins (HDL) in order to reduce cardiovascular risk. Targeting apolipoprotein A-I (apoA-I), the major protein carried on HDL particles, represents an attractive approach to promoting HDL by virtue of its ability to increase endogenous synthesis of functional HDL particles. A number of pharmacological strategies that target apoA-I, including upregulation of its production with the bromodomain and extraterminal (BET) protein inhibitor RVX-208, development of short peptide sequences that mimic its action, and administration as a component of reconstituted HDL particles, have undergone clinical development. The impact of these approaches on cardiovascular biomarkers will be reviewed.

The Changing Face of HDL and the Best Way to Measure It

BACKGROUND

HDL cholesterol (HDL-C) is a commonly used lipid biomarker for assessing cardiovascular health. While a central focus has been placed on the role of HDL in the reverse cholesterol transport (RCT) process, our appreciation for the other cardioprotective properties of HDL continues to expand with further investigation into the structure and function of HDL and its specific subfractions. The development of novel assays is empowering the research community to assess different aspects of HDL function, which at some point may evolve into new diagnostic tests.

CONTENT

This review discusses our current understanding of the formation and maturation of HDL particles via RCT, as well as the newly recognized roles of HDL outside RCT. The antioxidative, antiinflammatory, antiapoptotic, antithrombotic, antiinfective, and vasoprotective effects of HDL are all discussed, as are the related methodologies for assessing these different aspects of HDL function. We elaborate on the importance of protein and lipid composition of HDL in health and disease and highlight potential new diagnostic assays based on these parameters.

SUMMARY

Although multiple epidemiologic studies have confirmed that HDL-C is a strong negative risk marker for cardiovascular disease, several clinical and experimental studies have yielded inconsistent results on the direct role of HDL-C as an antiatherogenic factor. As of yet, our increased understanding of HDL biology has not been translated into successful new therapies, but will undoubtedly depend on the development of alternative ways for measuring HDL besides its cholesterol content.

The Therapeutic Role of Niacin in Dyslipidemia Management

There is abundant epidemiologic evidence to support the independent, inverse relationship between low levels of high-density lipoprotein cholesterol (HDL-C) and incident cardiovascular (CV) risk, the clinical importance of which is underscored by the high prevalence of low HDL-C in populations with coronary heart disease (CHD), with or without elevated levels of low-density lipoprotein cholesterol (LDL-C). The National Cholesterol Education Program recommended that optimal treatment for high-risk patients includes both lowering LDL-C and non-HDL-C to risk stratified levels and raising HDL-C when it is <40 mg/dL, although no target level for the latter lipoprotein was suggested. Niacin is the most powerful agent currently available for raising low levels of HDL-C. It also induces significant reductions in triglycerides, lipoprotein(a), and LDL-C levels while also favorably altering LDL particle size and number. In the Coronary Drug Project, niacin treatment was associated with significant reductions in CV events and long-term mortality, similar to the reductions seen in the statin monotherapy trials. In combination trials, niacin plus a statin or bile acid sequestrant produces additive reductions in CHD morbidity and mortality and promotes regression of coronary atherosclerosis. Recently, 2 clinical outcome trials (Atherothrombosis Intervention in Metabolic Syndrome With Low HDL/High Triglycerides and Impact on Global Health Outcomes [AIM-HIGH] and Second Heart Protection Study [HPS-2 THRIVE]) failed to show a reduction in CV events in patients treated to optimally low levels of LDL-C. Despite favorable effects on HDL-C and triglycerides, these studies did not demonstrate incremental clinical benefit with niacin when added to simvastatin, although notable limitations were identified in each of these trials. Thus, there is insufficient evidence from clinical trials to recommend HDL-targeted therapy for additional event reduction at the present time. However, niacin should continue to be used as an adjuvant therapy for reducing atherogenic lipoprotein burden in patients who have not reached their risk stratified LDL-C and non-HDL-C targets.

Association between triglycerides and cardiovascular events in primary populations: a meta-regression analysis and synthesis of evidence

Background

Triglyceride levels were found to be independently predictive of the development of primary coronary heart disease in epidemiologic studies. The objective of this study was to determine whether triglyceride levels were predictive of cardiovascular events in randomized controlled trials (RCTs) of lipid-modifying drugs.

Methods

We performed a systematic review and meta-regression analysis of 40 RCTs of lipid-modifying drugs with cardiovascular events as an outcome. The log of the rate ratio of cardiovascular events (eg, coronary death or myocardial infarction) was plotted against the proportional difference between treatment and control groups in triglyceride and other lipid levels (high density lipoprotein cholesterol [HDL-C], low density lipoprotein cholesterol [LDL-C], and total cholesterol) for all trials and for trials of primary and secondary prevention populations. Linear regression was used to determine the statistical significance of the relationship between lipid values and cardiovascular events.

Results

The proportional difference in triglyceride levels was predictive of cardiovascular events in all trials (P=0.005 for the slope of the regression line; N=40) and in primary prevention trials (P=0.010; N=11), but not in secondary prevention trials (P=0.114; N=25). The proportional difference in HDL-C was not predictive of cardiovascular events in all trials (P=0.822; N=40), or in trials of primary (P=0.223; N=11) or secondary (P=0.487; N=25) prevention. LDL-C levels were predictive of cardiovascular events in both primary (P=0.002; N=11) and secondary (P<0.001; N=25) populations.

Conclusions

Changes in triglyceride levels were predictive of cardiovascular events in RCTs. This relationship was significant in primary prevention populations but not in secondary prevention populations.

Statins in heart failure: do we need another trial?

Statins lower serum cholesterol and are employed for primary and secondary prevention of cardiovascular events. Clinical evidence from observational studies, retrospective data, and post hoc analyses of data from large statin trials in various cardiovascular conditions, as well as small scale randomized trials, suggest survival and other outcome benefits for heart failure. Two recent large randomized controlled trials, however, appear to suggest statins do not have beneficial effects in heart failure. In addition to lowering cholesterol, statins are believed to have many pleotropic effects which could possibly influence the pathophysiology of heart failure. Following the two large trials, evidence from recent studies appears to support the use of statins in heart failure. This review discusses the role of statins in the pathophysiology of heart failure, current evidence for statin use in heart failure, and suggests directions for future research.

Cardiovascular disease risk reduction by raising HDL cholesterol--current therapies and future opportunities

Since the first discovery of an inverse correlation between high-density lipoprotein-cholesterol (HDL-C) levels and coronary heart disease in the 1950s the life cycle of HDL, its role in atherosclerosis and the therapeutic modification of HDL-C levels have been major research topics. The Framingham study and others that followed could show that HDL-C is an independent cardiovascular risk factor and that the increase of HDL-C of only 10 mg·L(-1) leads to a risk reduction of 2-3%. While statin therapy and therefore low-density lipoprotein-cholesterol (LDL-C) reduction could lower coronary heart disease considerably; cardiovascular morbidity and mortality still occur in a significant portion of subjects already receiving therapy. Therefore, new strategies and therapies are needed to further reduce the risk. Raising HDL-C was thought to achieve this goal. However, established drug therapies resulting in substantial HDL-C increase are scarce and their effect is controversial. Furthermore, it is becoming increasingly evident that HDL particle functionality is at least as important as HDL-C levels since HDL particles not only promote reverse cholesterol transport from the periphery (mainly macrophages) to the liver but also exert pleiotropic effects on inflammation, haemostasis and apoptosis. This review deals with the biology of HDL particles, the established and future therapeutic options to increase HDL-C and discusses the results and conclusions of the most important studies published in the last years. Finally, an outlook on future diagnostic tools and therapeutic opportunities regarding coronary artery disease is given.

Fat lowers fat: purified phospholipids as emerging therapies for dyslipidemia

Dyslipidemia is a major coronary heart disease (CHD) risk factor. In spite of the proven efficacy of statin drugs in reducing CHD burden, there is still much room for the discovery of novel therapeutic agents to address the considerable residual cardiovascular risk that remains after treatment with currently available medications. In particular, there is an urgent demand for drugs capable of boosting the concentration and/or function of high-density lipoprotein (HDL) and apolipoprotein A-I (apo A-I), thereby promoting reverse cholesterol transport. Phospholipids are naturally occurring fats that play indispensible role in human health via their structural, energy storage, signal transduction and metabolic functions. Supplementation with either purified or mixed preparations of bioactive phospholipids has been reported to ameliorate a range of nutritional and cardiovascular disorders. Moreover, several lines of evidence have supported the efficacy of dietary phospholipids in reducing serum and hepatic contents of cholesterol and triglycerides, while increasing HDL-C and apo A-I levels. These beneficial effects of phospholipids could be attributed to their ability in reducing intestinal cholesterol absorption, enhancing biliary cholesterol excretion and modulating the expression and activity of transcriptional factors and enzymes that are involved in lipoprotein metabolism. Given their extreme safety and biocompatibility, dietary supplementation with phospholipid preparations, in particular phosphatidylinositol, appears as a novel and effective strategy that could be used as an alternative or adjunctive therapy to the current medications. The present review outlines the in-vitro, in-vivo and clinical findings on the anti-dyslipidemic effects of three most abundant phospholipids in the human body and diet namely phosphatidylcholine, phosphatidylethanolamine and phosphatidylinositol.

ApoA-I induction as a potential cardioprotective strategy: rationale for the SUSTAIN and ASSURE studies

BACKGROUND

Considerable interest has focused on the development of therapies that target the functionality of high-density lipoproteins (HDL). Upregulation of endogenous synthesis of the major protein on HDL particles, apolipoprotein A-I (apoA-I), represents a novel approach to generation of new HDL particles. The Study of Quantitative Serial Trends in Lipids with Apolipoprotein A-I Stimulation (SUSTAIN, NCT01423188) study aims to evaluate the lipid efficacy, safety and tolerability of an apoA-I inducer (RVX-208). The ApoA-I Synthesis Stimulation and Intravascular Ultrasound for Coronary Atheroma Regression Evaluation (ASSURE, NCT01067820) study aims to evaluate the effect of RVX-208 on plaque burden.

METHODS

In SUSTAIN, 172 patients with low levels of HDL-C will be randomized to receive RVX-208 100 mg bid or placebo for 24 weeks. The primary efficacy parameter will be the percentage change in HDL-C levels. In ASSURE, 310 patients with angiographic coronary artery disease and low HDL-C levels will be randomized to receive RVX-208 100 mg bid or placebo for 26 weeks. The primary efficacy parameter will be the nominal change in percent atheroma volume (PAV), determined by analysis of intravascular ultrasound (IVUS) images of matched coronary artery segments acquired at baseline and at 26-week follow-up. The effect of RVX-208 on other lipid and inflammatory markers, safety and tolerability will also be assessed in both studies.

CONCLUSION

ApoA-I induction represents a potential novel strategy to reduce cardiovascular risk, by generating nascent HDL particles. These studies will provide early evaluation of the effects of RVX-208 on lipids and atherosclerotic plaque.

Apo a-I modulating therapies

The substantial residual risk of cardiovascular events despite the implementation of effective lowering of low-density lipoprotein cholesterol highlights the need to develop additional cardioprotective therapies. Evidence from population and animal studies suggests that high-density lipoproteins (HDLs), the protective lipid particles, may represent a target for therapeutic modification. As a result intensive efforts are in progress to develop new agents that promote HDL activity. Among these different approaches, a range of strategies that target apolipoprotein A-I, the major protein carried on HDL, are being evaluated.

Type 2 diabetes is associated with reduced ATP-binding cassette transporter A1 gene expression, protein and function

OBJECTIVE

Increasing plasma glucose levels are associated with increasing risk of vascular disease. We tested the hypothesis that there is a glycaemia-mediated impairment of reverse cholesterol transport (RCT). We studied the influence of plasma glucose on expression and function of a key mediator in RCT, the ATP binding cassette transporter-A1 (ABCA1) and expression of its regulators, liver X receptor-α (LXRα) and peroxisome proliferator-activated receptor-γ (PPARγ).

METHODS AND RESULTS

Leukocyte ABCA1, LXRα and PPARγ expression was measured by polymerase chain reaction in 63 men with varying degrees of glucose homeostasis. ABCA1 protein concentrations were measured in leukocytes. In a sub-group of 25 men, ABCA1 function was quantified as apolipoprotein-A1-mediated cholesterol efflux from 2-3 week cultured skin fibroblasts. Leukocyte ABCA1 expression correlated negatively with circulating HbA1c and glucose (rho = -0.41, p<0.001; rho = -0.34, p = 0.006 respectively) and was reduced in Type 2 diabetes (T2DM) (p = 0.03). Leukocyte ABCA1 protein was lower in T2DM (p = 0.03) and positively associated with plasma HDL cholesterol (HDL-C) (rho = 0.34, p = 0.02). Apolipoprotein-A1-mediated cholesterol efflux correlated negatively with fasting glucose (rho = -0.50, p = 0.01) and positively with HDL-C (rho = 0.41, p = 0.02). It was reduced in T2DM compared with controls (p = 0.04). These relationships were independent of LXRα and PPARγ expression.

CONCLUSIONS

ABCA1 expression and protein concentrations in leukocytes, as well as function in cultured skin fibroblasts, are reduced in T2DM. ABCA1 protein concentration and function are associated with HDL-C levels. These findings indicate a glycaemia-related, persistent disruption of a key component of RCT.

Atorvastatin: evidence base 15 years later

HMG-CoA inhibitors have been widely used in primary and secondary prevention of atherosclerosis for more than 30 years. The evidence base for statins includes dozens of randomized clinical trials (RCT), involving hundreds of thousands patients. According to the results of the latest meta-analyses, reducing low-density lipoprotein cholesterol (LDL-CH) level by 1 mmol/l in statin-treated patients could decrease cardiovascular risk by 0,8 %. Atorvastatin (Liprimar®) is a modern synthetic statin, which has been thoroughly studied in several RCTs over the last 15 years. These trials demonstrated its effectiveness and tolerability in patients with chronic coronary heart disease, acute coronary syndrome (ACS), Type 2 diabetes mellitus, and arterial hypertension. In the studies comparing atorvastatin (10-80 mg/d) to other statins, baseline LDL-CH levels were reduced by 53 % in atorvastatintreated patients. Atorvastatin therapy was also well tolerated. Compared to placebo, atorvastatin therapy in the dose of 10 and 80 mg/d was associated with the incidence of hepatic transaminase elevation of 0,1 % and 0,6 %, respectively. This evidence base (in particular, the results of the trials on 80 mg/d atorvastatin therapy in ACS patients) has been a cornerstone of modern clinical guidelines, recommending target LDL-CH levels of 2 mmol/l. Currently, atorvastatin is the most widely prescribed statin in the majority of both developed and developing countries. Increasing initial dose and prescribing high-dose atorvastatin therapy (40-80 mg/d) could facilitate an improvement in treatment quality and a reduction in high levels of cardiovascular mortality inRussia.

Dyslipidaemia of obesity, metabolic syndrome and type 2 diabetes mellitus: the case for residual risk reduction after statin treatment

Dyslipidaemia is frequently present in obesity, metabolic syndrome (MetS) and type 2 diabetes mellitus (T2DM). The predominant features of dyslipidaemia in these disorders include increased flux of free fatty acids (FFA), raised triglyceride (TG) and low high density lipoprotein cholesterol (HDL-C) levels, a predominance of small, dense (atherogenic) low density lipoprotein cholesterol (LDL) particles and raised apolipoprotein (apo) B values Posprandial hyperlipidaemia may also be present. Insulin resistance (IR) appears to play an important role in the pathogenesis of dyslipidaemia in obesity, MetS and T2DM. The cornerstone of treatment of this IR-related dyslipidaemia is lifestyle changes and in diabetic patients, tight glycaemic control. In addition to these measures, recent clinical trials showed benefit with statin treatment. Nevertheless, a substantial percentage of patients treated with statins still experience vascular events. This residual vascular risk needs to be addressed. This review summarizes the effects of hypolipidaemic drug combinations (including statins with cholesterol ester protein inhibitors, niacin, fibrates or fish oil, as well as fibrate-ezetimibe combination) on the residual vascular risk in patients with obesity, MetS or T2DM.

ETC-216 for coronary artery disease

INTRODUCTION

Increasing attention has focused on the role of high-density lipoprotein function as a target for cardiprotection. Apolipoprotein A-I(Milano) (AIM) involves a single amino-acid mutation of the major wild-type protein carried on high-density lipoprotein (HDL) particles. Early evidence of beneficial activities of AIM has stimulated support in its development as a potential therapy to reduce cardiovascular risk.

AREAS COVERED

The importance of HDL as a target and early data supporting the beneficial effects of AIM are reviewed. All clinical studies of AIM found in PubMed are reviewed.

EXPERT OPINION

ETC-216 represents a lipid-deplete form of HDL containing recombinant AIM. While early evidence suggests that administration of ETC-216 promotes rapid regression of coronary atherosclerosis, bringing this compound to clinical practice will require further trials that evaluate its impact on cardiovascular events.

Efficacy and safety of a novel oral inducer of apolipoprotein a-I synthesis in statin-treated patients with stable coronary artery disease a randomized controlled trial

OBJECTIVES

The purpose of this study was to investigate the safety, tolerability, and efficacy of RVX-208, the first oral agent designed to enhance apolipoprotein (apo) A-I synthesis.

BACKGROUND

No agent that selectively induces synthesis of apoA-I has reached an advanced stage of clinical development.

METHODS

A total of 299 statin-treated patients with coronary artery disease were treated with placebo or with RVX-208 at a dose of 50, 100, or 150 mg twice daily for 12 weeks. Changes in lipid-related biomarkers, in addition to safety and tolerability, of RVX-208 were investigated.

RESULTS

For each dose of RVX-208, individual pairwise comparisons of apoA-I changes with placebo, the primary end point, did not achieve statistical significance. However, treatment with RVX-208 was associated with a dose-dependent increase in apoA-I levels by up to 5.6% (p = 0.035 for trend). Administration of RVX-208 resulted in significant increases in levels of high-density lipoprotein cholesterol (HDL-C) ranging from 3.2% to 8.3% (p = 0.02), and large HDL particles increased by 11.1% to 21.1% (p = 0.003). ApoA-I levels increased rapidly from 8 to 12 weeks, suggesting that peak pharmacological effect has not been achieved by the end of the 12-week study. Transient and reversible elevations in liver transaminases >3 times the upper limit of normal were observed in 18 patients treated with RVX-208, with no associated increase in bilirubin levels.

CONCLUSIONS

Administration of RVX-208 for 12 weeks was associated with increases in apoA-I, HDL-C, and concentration of large HDL particles, consistent with facilitation of cholesterol mobilization. Maximal increases in apoA-I may require longer exposure. An increase in liver enzymes was observed with active treatment. (Clinical Trial for Dose Finding and Safety of RVX000222 in Subjects With Stable Coronary Artery Disease; NCT01058018).

Raising HDL cholesterol in women

High-density lipoprotein cholesterol (HDL-C) concentration is essential in the determination of coronary heart disease (CHD) risk in women. This is especially true in the postmenopausal state, where lipid profiles and CHD risk mimic that of age-matched men. Thus, interventions designed to reduce CHD risk by raising HDL-C levels may have particular significance during the transition to menopause. This review discusses HDL-C-raising therapies and the role of HDL in the primary prevention of CHD in women. Lifestyle-based interventions such as dietary change, aerobic exercise regimens, and smoking cessation are initial steps that are effective in raising HDL-C, and available data suggest women respond similarly to men with these interventions. When combined with pharmacotherapy, the effects of these lifestyle alterations are further amplified. Though studies demonstrating gender-specific differences in therapy are limited, niacin continues to be the most effective agent in raising HDL-C levels, especially when used in combination with fibrate or statin therapy. Emerging treatments such as HDL mimetic therapy show much promise in further raising HDL-C levels and improving cardiovascular outcomes.

High-density lipoprotein and progression rate of atherosclerosis in intravascular ultrasound trials

Increasing interest has focused on the potential clinical utility of therapies that promote the biologic activity of high-density lipoprotein (HDL). Arterial wall imaging has been used in clinical trials to demonstrate that elevating HDL cholesterol has a beneficial impact on the natural history of the progression of atherosclerosis. As a result, it is likely that atherosclerosis imaging will become an integral component of early clinical development of novel therapies that enhance the functionality of HDL.

Effects of increasing high-density lipoprotein cholesterol and decreasing low-density lipoprotein cholesterol on the incidence of first acute coronary events (from the Air Force/Texas Coronary Atherosclerosis Prevention Study)

Reducing low-density lipoprotein (LDL) cholesterol with statins reduces cardiovascular risk, but the associations between increases in high-density lipoprotein (HDL) cholesterol and cardiovascular risk at different LDL levels have been less well characterized. To evaluate the associations between the 1-year changes in HDL cholesterol and LDL cholesterol with lovastatin and subsequent acute major coronary events (AMCEs), we studied 2,928 patients in the lovastatin arm who were followed for 5.2 years in a post-hoc analysis of the Air Force/Texas Coronary Atherosclerosis Prevention Study (AFCAPS/TexCAPS). The percentage of HDL cholesterol increase and apolipoproteins at year 1 and the incidence of AMCEs thereafter were assessed stratified by the LDL cholesterol levels. With lovastatin, LDL cholesterol was reduced by 25% on average to 115 mg/dl at year 1, and HDL cholesterol increased 6.0%. Patients with both an increase in HDL cholesterol of > or =7.5% and LDL cholesterol of <115 mg/dl at year 1 had the lowest event rate (3.53/1,000 person-years; p = 0.028). Similar results were found for an increase in HDL cholesterol of > or =7.5% and a decrease in LDL cholesterol of >25%, as well as for apolipoproteins A-I and B. The 1-year percent increase in HDL cholesterol appeared to be associated with a reduction in AMCEs in subsequent follow-up (p = 0.07 with the percentage of HDL cholesterol increase analyzed continuously). Patients with an HDL cholesterol increase of > or =7.5% had an AMCE rate of 5.18 compared with 7.66/1,000 person-years in patients with a lower HDL cholesterol increase (p = 0.08). In conclusion, lovastatin therapy was associated with a greater risk reduction of AMCEs when LDL cholesterol was substantially reduced and the HDL cholesterol increased by > or =7.5%.

Effect of lipid-modifying therapies on the functional quality of high-density lipoproteins: implications for drug development

BACKGROUND

Increasing interest has focused on the development of therapeutic strategies to promote the biological activity of high-density lipoproteins (HDL) to achieve more effective prevention of cardiovascular disease. The highly publicized failure of raising HDL cholesterol with the cholesteryl ester transfer protein inhibitor, torcetrapib, has fueled immense discussion with regard to the potential impact of lipid modifying therapies on the functional quality of HDL particles.

OBJECTIVE/METHOD

To review the literature that has investigated the role of HDL functionality in protection against cardiovascular disease.

CONCLUSION

It remains to be unequivocally demonstrated that therapies that directly target HDL are cardioprotective in humans. Increasing attention on the functional quality of HDL will be essentinal for developing new biomarkers and medical therapies.

Changes in remnant and high-density lipoproteins associated with hormone therapy and progression of coronary artery disease in postmenopausal women

OBJECTIVE

This study examined the effect of hormone therapy (HT) on the plasma concentration of remnant lipoprotein cholesterol (RLP-C) and high-density lipoprotein (HDL) subpopulations and the contribution of HT-related changes in these lipoproteins to the progression of coronary heart disease (CHD) in postmenopausal women.

METHODS

Study participants were 256 women who completed the Estrogen Replacement and Atherosclerosis (ERA) trial, a placebo-controlled, randomized trial that examined the effects of 3.2 years of conjugated equine estrogen (CEE, 0.625 mg/day) or CEE (0.625 mg/day) plus medroxyprogesterone acetate (MPA, 2.5mg/day) on postmenopausal women with established coronary atherosclerosis. Quantitative coronary angiography and plasma RLP-C and HDL subpopulations were assessed at baseline and at follow-up.

RESULTS

Relative to placebo, both CEE and CEE+MPA caused a significant reduction in plasma RLP-C concentrations and a significant increase in alpha1 and alpha2 HDL subpopulations. However, in the HT-treated subjects, faster progression of coronary atherosclerosis was observed in women who experienced the greatest reductions in RLP-C and in prebeta1 HDL subpopulations.

CONCLUSIONS

Our data suggest that individual variability in RLP-C and HDL subpopulation response to HT is a predictor of CHD progression. Lipoprotein response to HT may be an indirect marker of susceptibility to other harmful effect of HT in postmenopausal women with established CHD or an indication of formation of dysfunctional lipoproteins.

High-density Lipoprotein Cholesterol: Current Perspective for Clinicians

High-density lipoproteins are regarded as “good guys” but not always. Situations involving high-density lipoproteins are discussed and medication results are considered. Clinicians usually consider high-density lipoprotein cholesterol. Nicotinic acid is the best available medication to elevate high-density lipoprotein cholesterol and this appears beneficial for cardiovascular risk. The major problem with nicotinic acid is that many patients do not tolerate the associated flushing. Laropiprant decreases this flushing and has an approval in Europe but not in the United States. The most potent medications for increasing high-density lipoprotein cholesterol are cholesteryl ester transfer protein inhibitors. The initial drug in this class, torcetrapib, was eliminated by excess cardiovascular problems. Two newer cholesteryl ester transfer protein inhibitors, R1658 and anacetrapib, initially appear promising. High-density lipoprotein cholesterol may play an important role in improving cardiovascular risk in the 60% of patients who do not receive cardiovascular mortality/morbidity benefit from low-density lipoproteins reduction by statins.

Statin treatment, carotid atherosclerotic plaque macrophage infiltration and circulating inflammatory markers

BACKGROUND

Statin treatment is considered as first line therapy in patients with atherosclerotic disease. We evaluated the effect of pre-treatment with statins on carotid plaque infiltration by macrophages and on the circulating levels of proinflammatory cytokines in patients who underwent carotid endarterectomy.

PATIENTS AND METHODS

One hundred fourteen patients were enrolled; 89 men and 25 women (mean age 67+/-8 years; range 42-83 years). Fifty three patients (46%) were on statin treatment at least 3 months before endarterectomy and 61 (54%) had never received statin treatment. The serum levels of high sensitivity C reactive protein (hsCRP), serum amyloid A (SAA), tumor necrosis factor alpha (TNFalpha), interleukin (IL)-1beta and IL-6 were evaluated preoperatively. The intensity of macrophage infiltration was evaluated by immunochemistry, using the monoclonal antibody CD 68. The area of the plaque covered by macrophages was measured as a proportion of the whole plaque area, using a custom designed image tool analysis.

RESULTS

Patients on statins had lower serum total cholesterol levels (172+/-50 vs 194+/-35 mg/dl, p= 0.014), lower low density cholesterol levels (103+/-44 vs 123+/-31 mg/dl, p= 0.010) and lower serum hsCRP levels (1.8 [1.1-3.4] vs 3.4 [1.3-4.9] mg/l, p= 0.03), while SAA, TNFalpha, IL-6 and IL-1beta levels did not differ between the 2 groups. The infiltration of atherosclerotic plaque by macrophages was similar in statin treated patients and in controls (0.55+/-0.15% vs 0.49+/-0.19%, p= 0.21).

CONCLUSION

Patients on statins have similar macrophage accumulation in their carotid atherosclerotic plaques compared with patients not on statins. Inflammatory markers were also similar in both groups except for hsCRP which was significantly lower in those taking statins.

Influence of the timing of low-dose aspirin on tolerability of prolonged-release nicotinic acid in patients at elevated cardiovascular risk

OBJECTIVES

To investigate the effect of low-dose aspirin administered in the morning or evening on the rate of discontinuation of prolonged-release nicotinic acid (Niaspan) due to flushing in patients at elevated cardiovascular risk.

RESEARCH DESIGN AND METHODS

This was an observational, non-interventional study in patients at elevated cardiovascular risk due to cardiovascular disease or type 2 diabetes. Patients received prolonged-release nicotinic acid and aspirin under the usual care of their physician for 15 weeks.

MAIN OUTCOME MEASURES

The main outcome measure was the rate of treatment discontinuation for flushing. Other adverse drug reactions (ADRs) were also recorded. Lipid parameters were also measured.

RESULTS

The patient population included 539 subjects (70% male); 36% had type 2 diabetes, 80% had prior cardiovascular disease, and 37% had a family history of cardiovascular disease. The rate of treatment discontinuation due to flushing did not differ (p = 0.3375) between the morning aspirin group (10.6%) and the evening aspirin group (13.8%). The overall incidence of flushing was 57%. Most flushes were of mild or moderate severity and decreases occurred over time in both frequency and intensity. ADRs unrelated to flushing occurred in 6.6% of the morning aspirin group and 7.4% of the evening aspirin group. HDL-cholesterol increased by +21.3% in the overall population, together with moderate improvements in other lipid parameters.

CONCLUSIONS

Flushing was the most common ADR with prolonged-release nicotinic acid treatment, as expected. The timing of aspirin administration did not influence the rate of treatment discontinuations for flushing. Marked increases in HDL-cholesterol were observed.

Abnormal lipids in high-risk patients achieving cholesterol targets: a cross-sectional study of routinely collected UK general practice data

BACKGROUND AND OBJECTIVES

Lipid management in UK general practice targets the achievement of total cholesterol (TC) targets in high-risk individuals. Statins alone have a modest effect on non-LDL-C components of the lipid profile, leaving these patients at significant residual cardiovascular (CV) risk. Improving risk further would require the addition of non-statin therapies. This analysis explores what proportion of the UK population with cardiovascular disease (CVD) and TC levels at or below target may still be at risk because of residual dyslipidaemia.

METHODS

CV risk profiles were extracted from a research database of 602,222 patients from 98 UK general practices. Patients were categorised according to their prior CV history and use of statins. Mean values and proportions achieving treatment targets were assessed for TC, low density lipoprotein (LDL-C), high density lipoprotein (HDL-C) and triglycerides (TG).

RESULTS

In all, 48 499 patients with pre-existing CVD or diabetes were identified. 73% of statin-treated patients and 63% of untreated patients had a TC < or =5 mmol/L. 28.6% of patients treated to a TC target had LDL-C>3 mmol/L. Amongst those with both TC and LDL-C treated to target, 22.5% had low HDL-C and 37.2% had high triglyceride (TG). Within this group, more women than men had abnormal HDL-C (25.4 vs. 20.7%; p<0.0001). Patients with diabetes were more likely than non-diabetics to have abnormalities of both HDL-C (28.9 vs. 16.4%; p<0.0001) and triglyceride (44.9 vs. 29.5%; p<0.0001) despite normal TC and LDL-C.

CONCLUSIONS

Around 60% of high-risk patients have residual dyslipidaemias despite achieving the Quality and Outcomes Framework (QOF) TC target. New patterns of treatment are required in order to extend lipid management beyond simple total cholesterol lowering.

Cytochrome P450 and gene activation--from pharmacology to cholesterol elimination and regression of atherosclerosis

BACKGROUND

Lipoproteins are closely associated with the atherosclerotic vascular process. Elevated levels of high-density lipoprotein cholesterol (HDL-C) and apolipoprotein AI (apo AI) in plasma indicate a low probability of coronary heart disease (CHD) together with enhanced longevity, and elevated levels of low-density lipoprotein-cholesterol (LDL-C) and apo B indicate an increased risk of CHD and death. Studies linking gene activation and the induction of cytochrome P450 with elevated plasma levels of apo AI and HDL-C and lowered plasma levels of LDL-C presented a new potential approach to prevent and treat atherosclerotic disease.

OBJECTIVE AND METHODS

This is a review aimed at clarifying the effects of P450-enzymes and gene activation on cholesterol homeostasis, the atherosclerotic vascular process, prevention and regression of atherosclerosis and the manifestation of atherosclerotic disease, particularly CHD, the leading cause of death in the world.

RESULTS

P450-enzymes maintain cellular cholesterol homeostasis. They respond to cholesterol accumulation by enhancing the generation of hydroxycholesterols (oxysterols) and activating cholesterol-eliminating mechanisms. The CYP7A1, CYP27A1, CYP46A1 and CYP3A4 enzymes generate major oxysterols that enter the circulation. The oxysterols activate-via nuclear receptors-ATP-binding cassette (ABC) A1 and other genes, leading to the elimination of excess cholesterol and protecting arteries from atherosclerosis. Several drugs and nonpharmacologic compounds are ligands for the liver X receptor, pregnane X receptor and other receptors, activate P450 and other genes involved in cholesterol elimination, prevent or regress atherosclerosis and reduce cardiovascular events.

CONCLUSIONS

P450-enzymes are essential in the physiological maintenance of cholesterol balance. They activate mechanisms which eliminate excess cholesterol and counteract the atherosclerotic process. Several drugs and nonpharmacologic compounds induce P450 and other genes, prevent or regress atherosclerosis and reduce the occurrence of non-fatal and fatal CHD and other atherosclerotic diseases.

High-density lipoprotein and atheroma monitoring

PURPOSE OF REVIEW

To highlight the use of arterial wall imaging to evaluate the impact of therapies that promote high-density lipoproteins.

RECENT FINDINGS

High-density lipoproteins possess a number of biological properties, which have a direct impact on the extent and composition of atherosclerosis. Arterial wall imaging has been employed to demonstrate the beneficial influence on atherosclerosis of a number of therapeutic agents that modify high-density lipoprotein.

SUMMARY

Atheroma imaging has become an integral component of the clinical development of novel therapeutic agents designed to promote the atheroprotective activity of high-density lipoprotein.

Effects of statin treatment in men and women with stable coronary heart disease: a subgroup analysis of the GREACE Study

BACKGROUND

Reducing low-density lipoprotein cholesterol (LDL-C) levels to National Cholesterol Expert Panel (NCEP) goal is recommended. However, sex-specific effects may influence benefit.

METHODS AND RESULTS

In this post hoc analysis of the GREek Atorvastatin and Coronary heart disease (CHD) Evaluation [GREACE] study we investigated the extent in vascular event reduction by statin treatment according to sex. From a total of 1600 patients with stable CHD, 624/176 and 632/168 were men/women on atorvastatin or on usual care, respectively. During 3-year follow-up, comparison of atorvastatin treatment with usual care demonstrated a relative risk reduction (RRR) of the primary end point (all vascular events) of 54% in women (hazard ratio [HR] 0.46, 95% confidence interval [CI] 0.24-0.87, p=0.003) and of 50% in men (HR 0.50, 95% CI 0.32-0.70, p<0.001). The fall in LDL-C levels played the key role in end point reduction in both sexes. However, in men there was an additional benefit related to the atorvastatin-induced increase in high density lipoprotein cholesterol (HDL-C) and estimated glomerular filtration rate (eGFR), while in women end points were related to a substantial triglycerides (TG) reduction.

CONCLUSIONS

Treatment with atorvastatin to the NCEP LDL-C goal compared with 'usual care' significantly reduced CHD morbidity and mortality in both men and women. Both men and women benefited from statin treatment possibly with different mechanisms making a contribution over and above LDL-C reduction.

Cholesteryl ester transfer protein inhibition and HDL increase: has the dream ended?

Statins effectively lower plasma low-density lipoprotein cholesterol (LDL-C) levels and reduce the risk of vascular events. However, this benefit might be improved by dealing with other vascular risk factors such as high-density lipoprotein cholesterol (HDL-C). It follows that there has been an interest in drugs that raise plasma HDL-C levels. Among these drugs are the cholesteryl ester transfer protein (CETP) inhibitors. The first CETP inhibitor to be evaluated in an event-based trial was torcetrapib. This drug can considerably elevate serum HDL-C levels (e.g., by 72%). However, a recently published trial (ILLUMINATE) showed that torcetrapib used in combination with atorvastatin was associated with significantly more vascular events and deaths than atorvastatin alone. This finding resulted in the discontinuation of the torcetrapib development programme. The cause(s) of the adverse outcome remain speculative. It has been suggested that a significant rise in systolic blood pressure and possibly the quality of the HDL produced may be relevant. Despite this disappointing outcome it seems to be too early to close the book on CETP inhibitors because two other members of this class are being evaluated. These drugs (JTT-705 and anacetrapib) may be devoid of the adverse effect on systolic blood pressure. Eventually only appropriately designed, event-based trials, will settle the issue of whether CETP inhibitors are clinically useful.

Effect of Statins on Serum Apolipoprotein J and Paraoxonase-1 Levels in Patients With Ischemic Heart Disease Undergoing Coronary Angiography

It has been proposed that apolipoprotein J (apo J) and paraoxonase-1 (PON1) correlate with the extent and severity of ischemic heart disease (IHD). This article compares apo J and PON1 serum concentrations, PON1 activity, and the apo J/PON1 ratio in 138 IHD patients (64 statins users and 74 statin nonusers) referred for angiography and possible percutaneous coronary intervention. The effect of statin treatment on apo J and PON1 concentrations, PON1 activity, and the degree of coronary artery stenosis were evaluated. In both groups, apo J levels were increased, whereas PON1 concentration and activity decreased. IHD patients on statins had significantly lower apo J concentration and higher PON1 concentration and activity. Patients on statins had less coronary artery stenosis. High apo J levels, low PON1 levels, low PON1 activity, and a high apo J/PON1 ratio were associated with IHD. Statin treatment reverses these changes, probably by multiple beneficial actions.

Serum lipid profiles and their relationship to cardiovascular disease in the elderly: the PREV-ICTUS study

OBJECTIVE

To assess the relationship between different serum lipid profiles and the prevalence of established cardiovascular disease (CVD) in an elderly population.

RESEARCH DESIGN AND METHODS

An analysis was undertaken of the PREV-ICTUS population-based study on Spanish subjects aged > or =60 years. The following definitions were used: abnormal LDL cholesterol (LDL-C): > or =130 mg/dl (> or =3.3 mmol/L), or > or =100 mg/dl (> or =2.5 mmol/L) in those with diabetes or CVD, or treatment with any hypolipidaemic drug; low HDL cholesterol (HDL-C): <40 mg/dl (<1 mmol/L) (men), or <50 mg/dl (<1.3 mmol/L) (women), and abnormal triglycerides (TG): > or =150 mg/dl (> or =1.7 mmol/L) or treatment with fibrates. We defined eight groups: A (normal lipid profile), B (isolated abnormal LDL-C), C (isolated abnormal TG), D (isolated low HDL-C), E (abnormal LDL-C and HDL-C), F (abnormal LDL-C and TG), G (abnormal TG and HDL-C), H (abnormal LDL-C, HDL-C and TG). A multivariate analysis was performed to assess the relationship between each lipid profile and CVD.

RESULTS

A total of 6010 subjects (mean age 71.7 years, 53.5% women, 73.2% with hypertension, 29.2% with diabetes mellitus, 24.3% with CVD), were included in the analysis. LDL-C elevation was present in 78.1%, 23.3% had low HDL-C and 35.7% abnormal TG. Combined dyslipidaemias were frequent (40.3%). Odds ratios (95% confidence intervals) for CVD, compared with those with a normal lipid profile, were 2.07 (1.24-3.46) for abnormal HDL-C (p = 0.005), 4.09 (3.10-5.39) for abnormal LDL-C; 6.41 (4.59-8.95) for abnormal LDL-C plus HDL-C, 5.33 (3.98-7.14) for abnormal LDL-C plus TG and 7.59 (5.51-10.5) for those with the three parameters altered (all p < 0.001). Compared with those with isolated LDL-C elevation, those with abnormal LDL-C plus HDL-C had 1.57 (1.30-1.97) higher odds of having CVD (p < 0.001), the figures being 1.30 (1.11-1.53) for those with abnormal LDL-C plus TG and 1.86 (1.52-2.28) for those with abnormal LDL-C, TG plus HDL-C (p < 0.001).

CONCLUSIONS

Lipid abnormalities are frequent in the elderly, and are associated with the presence of CVD. Low HDL-C and/or abnormal TG levels, when added to abnormal LDL-C, are associated with a higher prevalence of CVD, suggesting the advisability of a comprehensive lipid evaluation and treatment earlier in life.

Effects of different doses of atorvastatin on human apolipoprotein B-100, B-48, and A-I metabolism

Nine hypercholesterolemic and hypertriglyceridemic subjects were enrolled in a randomized, placebo-controlled, double-blind, crossover study to test the effect of atorvastatin 20 mg/day and 80 mg/day on the kinetics of apolipoprotein B-100 (apoB-100) in triglyceride-rich lipoprotein (TRL), intermediate density lipoprotein (IDL), and LDL, of apoB-48 in TRL, and of apoA-I in HDL. Compared with placebo, atorvastatin 20 mg/day was associated with significant reductions in TRL, IDL, and LDL apoB-100 pool size as a result of significant increases in fractional catabolic rate (FCR) without changes in production rate (PR). Compared with the 20 mg/day dose, atorvastatin 80 mg/day caused a further significant reduction in the LDL apoB-100 pool size as a result of a further increase in FCR. ApoB-48 pool size was reduced significantly by both atorvastatin doses, and this reduction was associated with nonsignificant increases in FCR. The lathosterol-campesterol ratio was decreased by atorvastatin treatment, and changes in this ratio were inversely correlated with changes in TRL apoB-100 and apoB-48 PR. No significant effect on apoA-I kinetics was observed at either dose of atorvastatin. Our data indicate that atorvastatin reduces apoB-100- and apoB-48-containing lipoproteins by increasing their catabolism and has a dose-dependent effect on LDL apoB-100 kinetics. Atorvastatin-mediated changes in cholesterol homeostasis may contribute to apoB PR regulation.

Reaching goal in hypercholesterolaemia: dual inhibition of cholesterol synthesis and absorption with simvastatin plus ezetimibe

Lowering serum cholesterol levels reduces the risk of coronary heart disease (CHD)-related events. Statins are commonly prescribed as first-line treatment but many patients at high-risk for CHD still fail to reach their cholesterol or low-density lipoprotein cholesterol (LDL-C) goals with statin monotherapy. National and international guidelines for the prevention of CHD recommend the modification of lipid profiles and particularly LDL-C [e.g. the National Cholesterol Education Program Adult Treatment Panel III (NCEP ATP III; 2001) and Third Joint Task Force of European and other Societies on Cardiovascular Disease Prevention in Clinical Practice (2003) Guidelines]. Several recent clinical trials indicated an added benefit from aggressive lowering of LDL-C levels. Based on these findings, the NCEP ATP III revised the LDL-C target from < 100 mg/dL (2.6 mmol/L) to < 70 mg/dL (1.8 mmol/L) (optional target) for very high-risk patients and < 130 mg/dL (3.4 mmol/L) to < 100 mg/dL (2.6 mmol/L) for moderately high-risk patients. For patients who fail to achieve their LDL-C target, inhibiting the two main sources of cholesterol - synthesis and uptake - can produce more effective lipid lowering, allowing more patients to reach their LDL-C goal. Ezetimibe is a highly-selective inhibitor of cholesterol absorption and simvastatin is an evidence-based inhibitor of cholesterol synthesis. The LDL-C-lowering efficacy of targeting both major sources of cholesterol with ezetimibe plus simvastatin was demonstrated in several multicentre, double-blind, placebo-controlled trials in patients with hypercholesterolaemia. For patients who do not reach their cholesterol goal with a statin, adding ezetimibe 10 mg significantly reduces LDL-C compared with statin monotherapy. Thus, this treatment option may help patients reach the new 'stricter' cholesterol goals. This review, based on a Medline database search from January 2000 to August 2005, considers the LDL-C-lowering efficacy of ezetimibe and discusses the role of this agent for patients who fail to achieve guideline cholesterol goals with statin monotherapy.

Fenofibrate: a novel formulation (Triglide) in the treatment of lipid disorders: a review

Cardiovascular disease is the major cause of mortality worldwide and accounts for approximately 40% of all deaths. Dyslipidemia is one of the primary causes of atherosclerosis and effective interventions to correct dyslipidemia should form an integral component of any strategy aimed at preventing cardiovascular disease. Fibrates have played a major role in the treatment of hyperlipidemia for more than two decades. Fenofibrate is one of the most commonly used fibrates worldwide. Since fenofibrate was first introduced in clinical practice, a major drawback has been its low bioavailability when taken under fasting conditions. Insoluble Drug Delivery-Microparticle fenofibrate is a new formulation that has an equivalent extent of absorption under fed or fasting conditions. In this review, we will discuss the clinical pharmacology of fenofibrate, with particular emphasis on this novel formulation, as well as its lipid-modulating and pleiotropic actions. We will also analyze the major trial that evaluated fibrates for primary and secondary prevention of cardiovascular disease, the safety and efficacy profile of fibrate-statin combination treatment, and the current recommendations regarding the use of fibrates in clinical practice.

ABCA1 and atherosclerosis

ATP binding cassette transporter A1 (ABCA1) mediates the cellular efflux of phospholipids and cholesterol to lipid-poor apolipoprotein A1 (apoA1) and plays a significant role in high density lipoprotein (HDL) metabolism. ABCA1's role in the causation of Tangier disease, characterized by absent HDL and premature atherosclerosis, has implicated this transporter and its regulators liver-X-receptoralpha (LXRalpha) and peroxisome proliferator activated receptorgamma (PPARgamma) as new candidates potentially influencing the progression of atherosclerosis. In addition to lipid regulation, these genes are involved in apoptosis and inflammation, processes thought to be central to atherosclerotic plaque progression. A Medline-based review of the literature was carried out. Tangier disease and human heterozygotes with ABCA1 mutations provide good evidence that ABCA1 is a major candidate influencing atherosclerosis. Animal and in vitro experiments suggest that ABCA1 not only mediates cholesterol and phospholipid efflux, but is also involved in the regulation of apoptosis and inflammation. The complex and beneficial interactions between apoA1 and ABCA1 seem to be pivotal for cholesterol efflux. The expression of the ABCA1 is tightly regulated. Furthermore the plaque microenvironment could potentially promote ABCA1 protein degradation thus compromising cholesterol efflux. PPAR-LXR-ABCA1 interactions are integral to cholesterol homeostasis and these nuclear receptors have proven anti-inflammatory and anti-matrix metalloproteinase activity. Therapeutic manipulation of the ABCA1 transporter is feasible using PPAR and LXR agonists. PPAR agonists like glitazones and ABCA1 protein stabilization could potentially modify the clinical progression of atherosclerotic lesions.

The statins--therapeutic diversity in renal disease?

PURPOSE OF REVIEW

Statins significantly reduce cholesterol synthesis and reduce cardiovascular morbidity and mortality. In addition, they appear to have beneficial effects independent of their ability to lower cholesterol. Recent publications suggesting a potential role for statin therapy in chronic renal insufficiency, hypertension and following organ transplantation are reviewed.

RECENT FINDINGS

Pharmacokinetic studies have shown statins to be well-tolerated and effective in patients on long-term haemodialysis, providing equivalent control of lipid levels to that seen in matched controls. Preliminary clinical trials suggest that statins may have beneficial disease-modifying effects in chronic inflammatory disease. Furthermore, immunosuppressive and immunomodulatory actions may confer benefit following cardiac transplantation, but this remains to be demonstrated definitively in renal transplant patients. Data to date suggest that, in addition to reduction of cardiovascular risk, statins may help slow the progress of chronic renal insufficiency, particularly in patients with proteinuria. Addition of statin therapy may also contribute to the control of systemic and pulmonary hypertension.

SUMMARY

Encouraging data in support of a wider spectrum of use for statins are emerging. In addition to reduction of cardiovascular risk through lipid lowering, they may represent an important adjunctive therapy in patients with chronic kidney diseases and post-transplantation. However, further large, well-designed clinical trials are required before their widespread use can be recommended in this setting.

Fenofibric acid, an active form of fenofibrate, increases apolipoprotein A-I-mediated high-density lipoprotein biogenesis by enhancing transcription of ATP-binding cassette transporter A1 gene in a liver X receptor-dependent manner

OBJECTIVE

Fibrates are widely used drugs to reduce plasma triglyceride and increase high-density lipoprotein. Their active forms, fibric acids, are peroxisome proliferator-activated receptor-alpha activators, but no direct evidence has been demonstrated for their activation of ATP-binding cassette transporter A1 (ABCA1) in relation to clinically used fibrates. We investigated the reaction of fenofibric acid in this regard.

METHODS AND RESULTS

Fenofibric acid was examined for the effect of increase of ABCA1 activity. It enhanced ABCA1 gene transcription and its protein level in macrophage cell line cells and fibroblasts and increased apolipoprotein A-I-mediated cellular lipid release, all in a dose-dependent manner. Enhancement of the gene transcription was examined by using a reporter assay system for liver X receptor responsive element (LXRE) and its inactive mutant. The results demonstrated that the effect of fenofibric acid is dependent on active LXRE.

CONCLUSIONS

Fenofibric acid increased transcription of ABCA1 gene in a liver X receptor-dependent manner.