Drug treatment of lipid disorders

The use of statins in pediatrics: knowledge base, limitations, and future directions

The 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors, or statins, effectively reduce coronary morbidity and mortality in high-risk adults. They are also some of the most widely prescribed medications in the United States. Their use in pediatrics, however, remains circumscribed. In this article we review the cholesterol hypothesis and focus on the knowledge base of the use of statins in adults and children. We pay particular attention to the known effects of statins in primary and secondary prevention of cardiovascular events. The toxicities of statins and their limitations in pediatrics are then considered. The use of statins in conjunction with noninvasive modalities of assessing atherosclerotic burden are also reviewed. Finally, we suggest methods to advance the use of statins in childhood that introduce their potential benefits to those individuals at highest risk for future events.

The effect of biliary sphincterotomy on serum cholesterol level in postcholecystectomy patients: a pilot study

BACKGROUND

Cholesterol, in the form of bile salts, is reabsorbed from the small intestine via the enterohepatic circulation. Biliary sphincterotomy increases the delivery of bile to the terminal ileum. If the absorptive capacity is exceeded, cholesterol excretion may increase, resulting in a decrease in serum cholesterol levels and improvement in serum lipid profiles.

AIM

To determine the effect of biliary sphincterotomy on serum cholesterol levels in patients without biliary obstruction.

PATIENTS AND METHODS

Postcholecystectomy patients with type III biliary sphincter of Oddi dysfunction (disabling pancreatobiliary-type pain with normal liver function tests and bile duct diameter) who underwent biliary sphincterotomy were identified retrospectively from the endoscopic retrograde cholangiopancreatography database. Baseline (pre-endoscopic retrograde cholangiopancreatography) laboratory investigations (including cholesterol) were obtained for all patients. The effect of sphincterotomy on total cholesterol levels was noted in all patients who returned for subsequent procedures (temporary pancreatic stent removal or evaluation of recurrent symptoms), and also in the subgroup of patients with baseline hypercholesterolemia (higher than 5.18 mmol/L).

RESULTS

In the present pilot study, the performance of biliary sphincterotomy was associated with a reduction in total serum cholesterol levels in postcholecystectomy patients without biliary obstruction. This was statistically significant in patients with a baseline cholesterol level higher than 5.18 mmol/L. A possible effect on low- and high-density lipoprotein concentrations was not evaluated. The influence of dietary changes and exercise were not accounted for.

CONCLUSION

A prospective, controlled study involving a larger series of patients is required to determine whether biliary sphincterotomy lowers cholesterol levels and improves lipid profiles.

Familial dyslipidaemias: an overview of genetics, pathophysiology and management

Plasma lipid disorders can occur either as a primary event or secondary to an underlying disease or use of medications. Familial dyslipidaemias are traditionally classified according to the electrophoretic profile of lipoproteins. In more recent texts, this phenotypic classification has been replaced with an aetiological classification. Familial dyslipidaemias are generally grouped into disorders leading to hypercholesterolaemia, hypertriglyceridaemia, a combination of hyper-cholesterolaemia and hypertriglyceridaemia, or abnormal high-density lipoprotein-cholesterol (HDL-C) levels. The management of these disorders requires an understanding of plasma lipid and lipoprotein metabolism. Lipid transport and metabolism involves three general pathways: (i) the exogenous pathway, whereby chylomicrons are synthesised by the small intestine, and dietary triglycerides (TGs) and cholesterol are transported to various cells of the body; (ii) the endogenous pathway, whereby very low-density lipoprotein-cholesterol (VLDL-C) and TGs are synthesised by the liver for transport to various tissues; and (iii) the reverse cholesterol transport, whereby HDL cholesteryl ester is exchanged for TGs in low-density lipoptrotein (LDL) and VLDL particles through cholesteryl ester transfer protein in a series of steps to remove cholesterol from the peripheral tissues for delivery to the liver and steroidogenic organs. The plasma lipid profile can provide a framework to guide the selection of appropriate diet and drug treatment. Many patients with hyperlipoproteinaemia can be treated effectively with diet. However, dietary regimens are often insufficient to bring lipoprotein levels to within acceptable limits. In this article, we review lipid transport and metabolism, discuss the more common lipid disorders and suggest some management guidelines. The choice of a particular agent depends on the baseline lipid profile achieved after 6-12 weeks of intense lifestyle changes and possible use of dietry supplements such as stanols and plant sterols. If the predominant lipid abnormality is hypertriglyceridaemia, omega-3 fatty acids, a fibric acid derivative (fibrate) or nicotinic acid would be considered as the first choice of therapy. In subsequent follow-up, when LDL-C is >130 mg/dL (3.36 mmol/L) then an HMG-CoA reductase inhibitor (statin) should be added as a combination therapy. If the serum TG levels are <500 mg/dL (2.26 mmol/L) and the LDL-C values are over 130 mg/dL (3.36 mmol/L) then a statin would be the first drug of choice. The statin dose can be titrated up to achieve the therapeutic goal or, alternatively, ezetimibe can be added. A bile acid binding agent is an option if the serum TG levels do not exceed 200 mg/dL (5.65 mmol/L), otherwise a fibrate or nicotinic acid should be considered. The decision to treat a particular person has to be individualised.

Strategies for management and treatment of dyslipidemia in HIV/AIDS

With the improved survival of HIV-infected patients, there are increased concerns about the long-term effects of treatment, including protease inhibitor (PI)-related dyslipidemia. Some 50-70% of patients receiving combination antiretroviral therapy (ART) involving PIs develop lipid abnormalities consisting of elevated levels of total cholesterol, low-density lipoprotein cholesterol and triglycerides that are well-known risk factors for cardiovascular disease. Treatment of HIV dyslipidemia should include lifestyle modifications such as a low-fat diet, increased exercise, reduced alcohol consumption and smoking cessation. In many patients, however, these changes alone will not correct lipid levels. In some patients, changing the PI component of ART to another PI or non-PI and/or lipid-lowering drugs has proven successful. Each approach is associated with advantages and limitations and the need to maintain viral suppression must be balanced with the need to treat abnormal lipid levels.

A moderate-fat diet for combined hyperlipidemia and metabolic syndrome

A low-fat diet is recommended for hyperlipidemia. However, low-density lipoprotein (LDL) responses depend on the type of hyperlipidemia (ie, simple hypercholesterolemia or combined hyperlipidemia). In combined hyperlipidemia, which is typical of patients with metabolic syndrome, LDL levels are only one third as responsive to fat and cholesterol as simple hypercholesterolemia. The diminished dietary sensitivity of combined hyperlipidemia is explained by diminished intestinal absorption of cholesterol, a feature of metabolic syndrome. In turn, combined hyperlipidemia is caused by heightened lipid secretion by the liver. A moderate-fat, moderate-carbohydrate diet employing allowable fats has the promise of reducing endogenous lipoprotein production in combined hyperlipidemia. Triglyceride, LDL, and small-dense LDL should be lower, and high-density lipoprotein, apoprotein A-I, and buoyant LDL should be higher. A test of this dietary strategy on lipoproteins and downstream benefits on inflammatory mediators, oxidative stress, and vascular reactivity is now underway.

Sex differences in lipoprotein metabolism and dietary response: basis in hormonal differences and implications for cardiovascular disease

The transport of fat in the blood stream is approximately twice as fast in women as men. Disease states such as obesity and diabetes are associated with greater lipoprotein abnormalities in women compared with men. A greater increment in cardiovascular disease risk in women is linked to these abnormalities. A greater change in triglyceride level and a lesser change in low-density lipoprotein are observed in women than men with high-carbohydrate or high-fat feeding. Most consistent are greater changes in high-density lipoprotein (HDL), HDL(2), and apolipoprotein A-I levels in women compared with men with high-carbohydrate or high-fat feeding. Dietary fat restriction in women appears to have a less beneficial lipoprotein effect than in men. Dietary fat restriction for heart disease prevention may be less ideal in women than in men.

Management of dyslipidemia in the metabolic syndrome: recommendations of the Spanish HDL-Forum

In order to characterize the metabolic syndrome it becomes necessary to establish a number of diagnostic criteria. Because of its impact on cardiovascular morbidity/mortality, considerable attention has been focussed on the dyslipidemia accompanying the metabolic syndrome. The aim of this review is to highlight the fundamental aspects of the pathophysiology, diagnosis, and the treatment of the metabolic syndrome dyslipidemia with recommendations to clinicians. The clinical expression of the metabolic syndrome dyslipidemia is characterized by hypertriglyceridemia and low levels of high-density lipoprotein-cholesterol (HDL-C). In addition, metabolic syndrome dyslipidemia is associated with high levels of apolipoprotein (apo) B-100-rich particles of a particularly atherogenic phenotype (small dense low-density lipoprotein-cholesterol [LDL-C]. High levels of triglyceride-rich particles (very low-density lipoprotein) are also evident both at baseline and in overload situations (postprandial hyperlipidemia). Overall, the 'quantitative' dyslipidemia characterized by hypertriglyceridemia and low levels of HDL-C and the 'qualitative' dyslipidemia characterized by high levels of apo B-100- and triglyceride-rich particles, together with insulin resistance, constitute an atherogenic triad in patients with the metabolic syndrome. The therapeutic management of the metabolic syndrome, regardless of the control of the bodyweight, BP, hyperglycemia or overt diabetes mellitus, aims at maintaining optimum plasma lipid levels. Therapeutic goals are similar to those for high-risk situations because of the coexistence of multiple risk factors. The primary goal in treatment should be achieving an LDL-C level of <100 mg/dL (or <70 mg/dL in cases with established ischemic heart disease or risk equivalents). A further goal is increasing the HDL-C level to >or=40 mg/dL in men or 50 mg/dL in women. A non-HDL-C goal of 130 mg/dL should also be aimed at in cases of hypertriglyceridemia. Lifestyle interventions, such as maintaining an adequate diet, and a physical activity program, constitute an essential part of management. Nevertheless, when pharmacologic therapy becomes necessary, fibrates and HMG-CoA reductase inhibitors (statins) are the most effective drugs in controlling the metabolic syndrome hyperlipidemia, and are thus the drugs of first choice. Fibrates are effective in lowering triglycerides and increasing HDL-C levels, the two most frequent abnormalities associated with the metabolic syndrome, and statins are effective in lowering LDL-C levels, even though hypercholesterolemia occurs less frequently. In addition, the combination of fibrates and statins is highly effective in controlling abnormalities of the lipid profile in patients with the metabolic syndrome.

Influence of Drug Transporter Polymorphisms on Pravastatin Pharmacokinetics in Humans

The role of drug transporters in pravastatin disposition is underlined by the fact that pravastatin does not undergo significant cytochrome P-450 (CYP)-mediated biotransformation. The organic anion transporting polypeptide 1B1 (OATP1B1), encoded by SLCO1B1, and multidrug resistance-associated protein 2 [MRP2 (ABCC2)], are thought to be the major transporters involved in the pharmacokinetics of pravastatin in humans. Other transporters that may play a role include OATP2B1, organic anion transporter 3 (OAT3), bile salt export pump (BSEP), and the breast cancer resistance protein (BCRP). OATP1B1 and MRP2 mediate the hepatic uptake and biliary excretion of pravastatin, respectively. The SLCO1B1 and ABCC2 polymorphisms probably contribute to the high interindividual variability in pravastatin disposition. Recent small studies have characterized the impact of the SLCO1B1 polymorphism on pravastatin in humans, and especially the c.521T>C single-nucleotide polymorphism (SNP) seems to be an important determinant of pravastatin pharmacokinetics. Pravastatin plasma concentrations may be up to 100% higher in subjects carrying the c.521C variant, as found in the *5, *15, *16, and *17 haplotypes, reflecting diminished OATP1B1-mediated uptake into the major site of pravastatin elimination, the liver. The SLCO1B1 polymorphism seems to have a similar impact on the pharmacokinetics of single- and multiple-dose pravastatin. Overall, 2-5% of individuals in various populations may be expected to show markedly elevated plasma pravastatin concentrations due to the SLCO1B1 polymorphism. Of note, the impact of the SLCO1B1 polymorphism on statins may be dependent on ethnicity. Although individuals with a diminished hepatic uptake of pravastatin might be expected to show reduced cholesterol-lowering efficacy due to lower intracellular pravastatin concentrations, there is preliminary evidence to suggest that the SLCO1B1 polymorphism is not a major determinant of non-response to pravastatin. The possible consequences of drug transporter polymorphisms, especially the SLCO1B1 and ABCC2 polymorphisms, for the lipid-lowering efficacy and tolerability of pravastatin in various ethnic groups warrant further study.

Cholesterol absorption inhibitors: defining new options in lipid management

Although many studies have documented that reduction of plasma cholesterol levels decreases the risk of coronary artery disease, it remains the most common cause of death in the Western world. Current therapeutic options are effective in lowering cholesterol, especially in clinical trials, but clinical application is not optimized for many reasons. Dietary restriction for long-term management of hypercholesterolemia is helpful but usually insufficient to reduce low-density lipoprotein cholesterol (LDL-C) to goal levels. Powerful drugs are available, but these are often insufficient to meet the clinical demands for cholesterol-lowering therapy. Phytosterols and phytostanols have been partially effective by providing some inhibition of absorption of cholesterol. Compounds that specifically and more effectively block intestinal absorption of dietary and biliary cholesterol should provide a significant new agent for altering lipoprotein concentrations favorably. Ezetimibe is the first of this class of compounds that act at the gut epithelium to reduce cholesterol absorption in the milligram dose range markedly. Clinical studies indicate that ezetimibe effectively decreases LDL-C by 15 to 20% as monotherapy, with a favorable safety profile. Moreover, results from preliminary clinical trials indicate that ezetimibe given concomitantly with a statin provides additive efficacy. The combination represents a new approach to lipid management, achieving greater LDL-C and triglyceride reductions and greater improvements in HDL-C than statin monotherapy. This could offer another important option in clinical practice for management of hypercholesterolemic patients.

Lipoprotein effects of combined ezetimibe and colesevelam hydrochloride versus ezetimibe alone in hypercholesterolemic subjects: a pilot study

Two drug classes act in the intestine to lower cholesterol. Ezetimibe inhibits cholesterol absorption, whereas bile acid-binding resins enhance cholesterol excretion via enhanced conversion to bile acids. Combining these 2 classes may be beneficial, but cholestyramine binds ezetimibe, and the combined effect of colesevelam hydrochloride and ezetimibe was little studied. The aim of the study was to determine if adding colesevelam HCl to ezetimibe provides additional lowering of low-density lipoprotein- and apolipoprotein B-containing lipoproteins or alters ezetimibe levels. Twenty subjects with low-density lipoprotein cholesterol (LDL-C) levels of 130 mg/dL or higher were enrolled and taught a National Cholesterol Education Program Step I diet. At a second baseline visit, lipoproteins were measured and subjects were randomly allocated to (1) ezetimibe 10 mg daily with placebo colesevelam HCl twice daily (E) or (2) ezetimibe 10 mg daily with 1.875 g colesevelam HCl twice daily (E + C). Lipoproteins were measured 6 and 12 weeks after initiating treatment. Baseline characteristics (mean +/- SD) were statistically indistinguishable in E vs E + C: LDL-C (mg/dL), 167 +/- 26 and 158 +/- 27; triglyceride, 134 +/- 75 and 140 +/- 67; and BMI, 29.4 +/- 4.9 and 27.8 +/- 6.6 kg/m(2), respectively. Percent changes after 12 weeks in E vs E + C were as follows: LDL-C, -24 +/- 12 vs -30 +/- 11 (P = .102); triglyceride, -19 +/- 34 vs 36 +/- 85 (P = .054; at 6 weeks, P = .009); total cholesterol, -19 +/- 9 vs -15 +/- 8 (P = .50); non-high-density lipoprotein cholesterol, -25 +/- 10 vs -21 +/- 11 (P = .70); apolipoprotein B, -31 +/- 14 vs -22 +/- 14 (P = .41). Plasma ezetimibe levels at 12 weeks were 21% lower in E + C vs E, a nonsignificant difference (P = .54). In conclusion, in the short term, colesevelam HCl may not consistently add cholesterol-lowering benefit to ezetimibe. This observation requires confirmation.

Renal injury: similarities and differences in male and female rats with the metabolic syndrome

The metabolic syndrome is complicated by nephropathy in humans and rats, and males are more affected than females. We hypothesized that female rats had reduced expression of glomerular oxidized low-density lipoprotein (oxLDL) receptor 1 (LOX-1), attendant glomerular oxidant injury, and renal inflammation. Three groups, obese males (OM), obese females (OF), and lean males (LM) of first-generation (F(1)) hybrid rats derived from the Zucker fatty diabetic (ZDF) strain and the spontaneous hypertensive heart failure rat (SHHF/Gmi-fa) were studied from 6 to 41 weeks of age. OM had severe renal oxidant injury and renal failure. Their glomeruli expressed the LOX-1, and exhibited heavier accumulation of the lipid peroxide 4-hydroxynonenal (4-HNE). OM had compromised mitochondrial enzyme function, more renal fibrosis, and vascular leakage. Younger LM, OM, and OF ZS (ZDF/SHHF F(1) hybrid rat) rats, studied from 6 to 16 weeks of age, showed that unutilized renal lipids were comparable in OM and OF, although young OM had worse nephropathy and inflammation. In conclusion, glomerular LOX-1 expression is coupled to deposits of 4-HNE and glomerulosclerosis in OM. We presume that LOX-1 enhances glomerular uptake of oxidized lipids and renal inflammation, causing greater oxidant stress and severe glomerulosclerosis. In OF, renal protection from lipid oxidants appears to be conferred by blunted glomerular LOX-1 expression and renal inflammation.

Polymyositis evolving after rhabdomyolysis associated with HMG-CoA reductase inhibitors: a report of two cases

3-Hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors are commonly used for treatment of hyperlipidemia and its deleterious effects. Myotoxicity has been associated with use of these agents. We report two cases of inflammatory myopathy in patients receiving these agents that did not respond to drug withdrawal and required immunosuppressive treatment. One of these patients developed an antibody to histidyl tRNA synthetase or Jo-1, an autoantibody associated with idiopathic inflammatory myopathies. We suggest that HMG-CoA reductase inhibitor-associated myotoxicity may trigger an immune-mediated inflammatory myopathy. Patients whose muscle abnormalities do not resolve with drug withdrawal should be considered for muscle biopsy.

Antisense oligonucleotides as therapeutics for hyperlipidaemias

Hyperlipidaemia, due to elevations of low-density lipoprotein cholesterol (LDL-C) or triglycerides (TGs), is recognised as a significant risk factor contributing to the development of coronary heart disease (CHD), the leading cause of morbidity and mortality in the Western world. Even though a variety of established antihyperlipidaemic agents are available, the majority of high-risk patients do not reach their lipid goals, indicating the need for new and more effective therapeutics to be used alone or as combination agents with existing drugs. Antisense oligonucleotides (ASOs), designed to specifically and selectively inhibit novel targets involved in cholesterol/TG homeostasis, represent a new class of agents that may prove beneficial for the treatment of hyperlipidaemias resulting from various genetic, metabolic or behavioural factors. This article describes the antisense technology platform, highlights the advantages of these novel drugs for the treatment of hyperlipidaemia and reviews the current research in this area.

Effectiveness calculation in economic analysis: the case of statins for cardiovascular disease prevention

OBJECTIVES

This report aimed to evaluate the calculation of estimates of effectiveness in cost effectiveness analyses of statins for cardiovascular disease prevention.

METHODS

Methodological aspects were reviewed of seven primary studies (based on trial results) and 12 secondary modelling studies (extrapolated) on the cost effectiveness of statin treatment, published between 1995 and 2002. Estimates of life years gained were extracted and compared with estimates calculated using the Dutch male life table of 1996-2000.

RESULTS

Of the seven primary modelling analyses, six showed all the essential data. They estimated that 3 to 5.6 years (average 4.6 years) of statin treatment resulted in 0.15 to 0.41 years (average 0.3 years) saved over a lifetime time horizon. In contrast none of the 12 secondary modelling studies provided transparent results. They assumed lifelong treatment, leading to life table estimations of 2.4 and 2.0 (undiscounted) years saved for 40 and 60 year olds, with peak savings at around the mean age of death: 75-80 years. With 5% discounting, these effects reduced to 0.4 and 0.8 years respectively.

CONCLUSION

Reporting of essential data and assumptions on statin treatment was poor for secondary modelling analyses and satisfactory for primary modelling studies. Secondary modeling studies made assumptions on long term effectiveness that were hard to justify with the available evidence, and that led to the majority of life years saved at high ages. Further standardisation in economic analyses is important to guarantee transparency and reproducibility of results.

Statin-induced rhabdomyolysis

Simvastatin and other HMG-CoA reductase inhibitors (statins) are one of the most frequently prescribed class of medications in the United States, with over 15 million Americans taking these drugs. Relatively rare adverse effects related to the known toxic effects of these drugs are more common than generally realized. Clinically significant statin-induced rhabdomyolysis is an uncommon but life-threatening adverse effect. We describe a case of simvastatin-induced rhabdomyolysis. Current knowledge of the pharmacology of the HMG-CoA reductase inhibitors and the drug interactions that potentiate these adverse effects are discussed. The clinical features of rhabdomyolysis and current treatment recommendations are presented.

Stroke prevention and statin treatment

Randomized trials with statins have shown a modest but significant absolute reduction in the incidence of stroke in patients with a previous myocardial infarction. The reasons for the positive statin effect on stroke endpoint are unclear, because a link between serum cholesterol level and stroke never has been established. However, positive results of statin trials were mainly obtained in patients with an average or a low serum cholesterol level. Statins have a good overall safety profile. Statins reduced stroke incidence in high-risk (mainly coronary heart disease, diabetics, and hypertensives) population even with a normal baseline blood cholesterol level. In patients with prior strokes, statins reduce the incidence of coronary events, but it is not yet proven if drugs of this class actually reduce the incidence of recurrent strokes in terms of secondary prevention.

Evidence for prescribing exercise as therapy in chronic disease

Considerable knowledge has accumulated in recent decades concerning the significance of physical activity in the treatment of a number of diseases, including diseases that do not primarily manifest as disorders of the locomotive apparatus. In this review we present the evidence for prescribing exercise therapy in the treatment of metabolic syndrome-related disorders (insulin resistance, type 2 diabetes, dyslipidemia, hypertension, obesity), heart and pulmonary diseases (chronic obstructive pulmonary disease, coronary heart disease, chronic heart failure, intermittent claudication), muscle, bone and joint diseases (osteoarthritis, rheumatoid arthritis, osteoporosis, fibromyalgia, chronic fatigue syndrome) and cancer, depression, asthma and type 1 diabetes. For each disease, we review the effect of exercise therapy on disease pathogenesis, on symptoms specific to the diagnosis, on physical fitness or strength and on quality of life. The possible mechanisms of action are briefly examined and the principles for prescribing exercise therapy are discussed, focusing on the type and amount of exercise and possible contraindications.

Effects of raloxifene on lipid and lipoprotein levels in postmenopausal osteoporotic women with and without hypertriglyceridemia

This post hoc analysis reports the effects of raloxifene on lipids and lipoproteins in 2659 women with either normal (< or =150 mg/dL) or high (>150 mg/dL) triglyceride levels from a substudy of the Multiple Outcomes of Raloxifene Evaluation (MORE) trial. In both triglyceride subgroups, raloxifene significantly improved low-density lipoprotein cholesterol, total cholesterol, non-high-density lipoprotein cholesterol (HDL-C), apolipoprotein B, apolipoprotein A-I, and fibrinogen compared with placebo (P < .05). After raloxifene treatment, women with high triglycerides experienced an equal or more robust reduction in cholesterol, lipoprotein parameters, and ratios of total cholesterol to HDL-C and non-HDL-C to HDL-C than was observed in women with normal triglycerides (P < .05). Mean levels of low-density lipoprotein cholesterol and apolipoprotein B were reduced by 16.5% and 15.8%, respectively, in women with high triglycerides, and by 12.7% and 11.3%, respectively, in women with normal triglycerides. These findings further substantiate that raloxifene improves concentrations of both cholesterol and beta-lipoprotein. The subgroup of women with high triglycerides, who have elevated cardiovascular risk, appear to derive at least equal, if not greater, overall effect on lipid and lipoprotein lowering with raloxifene.

Efficacy and safety of atorvastatin in the prevention of cardiovascular end points in subjects with type 2 diabetes: the Atorvastatin Study for Prevention of Coronary Heart Disease Endpoints in non-insulin-dependent diabetes mellitus (ASPEN)

OBJECTIVE

Cardiovascular disease (CVD) risk is increased in type 2 diabetes. The purpose of this study was to assess the effect of 10 mg of atorvastatin versus placebo on CVD prevention in subjects with type 2 diabetes and LDL cholesterol levels below contemporary guideline targets.

RESEARCH DESIGN AND METHODS

Subjects were randomly assigned to receive 10 mg of atorvastatin or placebo in a 4-year, double-blind, parallel-group study. The composite primary end point comprised cardiovascular death, nonfatal myocardial infarction, nonfatal stroke, recanalization, coronary artery bypass surgery, resuscitated cardiac arrest, and worsening or unstable angina requiring hospitalization.

RESULTS

A total of 2,410 subjects with type 2 diabetes were randomized. Mean LDL cholesterol reduction in the atorvastatin group over 4 years was 29% versus placebo (P < 0.0001). When we compared atorvastatin versus placebo, composite primary end point rates were 13.7 and 15.0%, respectively (hazard ratio 0.90 [95% CI 0.73-1.12]). In the subset of 1,905 subjects without prior myocardial infarction or interventional procedure, 10.4% of atorvastatin- and 10.8% of placebo-treated subjects experienced a primary end point (0.97 [0.74-1.28]). In the 505 subjects with prior myocardial infarction or interventional procedure, 26.2% of atorvastatin- and 30.8% of placebo-treated subjects experienced a primary end point (0.82 [0.59-1.15]). Relative risk reductions in fatal and nonfatal myocardial infarction were 27% overall (P = 0.10) and 19% (P = 0.41) and 36% (P = 0.11) for subjects without and with prior myocardial infarction or interventional procedure, respectively.

CONCLUSIONS

Composite end point reductions were not statistically significant. This result may relate to the overall study design, the types of subjects recruited, the nature of the primary end point, and the protocol changes required because of changing treatment guidelines. For these reasons, the results of the Atorvastatin Study for Prevention of Coronary Heart Disease Endpoints in Non-Insulin-Dependent Diabetes Mellitus (ASPEN) did not confirm the benefit of therapy but do not detract from the imperative that the majority of diabetic patients are at risk of coronary heart disease and deserve LDL cholesterol lowering to the currently recommended targets.

Ezetimibe: A First-in-Class, Novel Cholesterol Absorption Inhibitor

Significant numbers of patients at risk for coronary heart disease (CHD) fail to reach National Cholesterol Education Program (NCEP)-designated low density lipoprotein cholesterol (LDL-C) goals in spite of the wide range of currently available treatments, including combination therapies. Ezetimibe, the first in a class of novel cholesterol absorption inhibitors, demonstrated lipid-lowering and antiatherosclerotic activity in experimental and clinical hypercholesterolemia. Studies in hypercholesterolemic dogs showed that ezetimibe coadministered with statins caused greater lipid-lowering effects compared to either drug alone. These effects were confirmed in clinical studies of patients with primary hypercholesterolemia where initiation of treatment with ezetimibe plus a statin, or addition of ezetimibe to ongoing statin therapy, produced significant incremental reductions in LDL-C, as well as incremental increases in high-density lipoprotein cholesterol (HDL-C) and reductions in triglyceride levels. Combination therapy also significantly increased the number of patients attaining LDL-C goal at the end of treatment, compared to statin monotherapy. In studies using simvastatin, atorvastatin, pravastatin, and lovastatin, addition of ezetimibe to low dose statin was as effective as a 2- to 3-fold upward titration of the corresponding statin dose. Ezetimibe-statin combination therapy provided similar improvements in patients with primary hypercholesterolemia, as well as with heterozygous and homozygous familial hypercholesterolemia. Ezetimibe monotherapy effectively reduced plasma campesterol and sitosterol in patients with homozygous sitosterolemia. Clinical studies showed that ezetimibe was well tolerated, with a safety profile comparable to placebo when administered as monotherapy and comparable to statin alone when coadministered with a statin. These data provide strong evidence that, through their complementary lipid-lowering mechanisms, ezetimibe coadministered with a statin offers an effective combination treatment option for patients with hypercholesterolemia, including those with genetically inherited disease.

N-3 fatty acid supplementation decreases plasma homocysteine in diabetic dyslipidemia treated with statin–fibrate combination

The aim of this study was to study the effect of adding polyunsaturated fatty acid (PUFA) n-3 or placebo (containing oleic acid) to a combined statin-fibrate treatment on plasma lipoproteins, lipoperoxidation, glucose homeostasis, total homocysteine (tHcy) and microalbuminuria (MA) in patients with diabetic dyslipidemia (DDL). Twenty-four patients, who did not fulfill the recommended target lipid values with combined hypolipidemic therapy (pravastatin 20 mg+micronized fenofibrate 200 mg daily), were supplemented with 3.6 g PUFA n-3 daily for 3 months or placebo (olive oil) for the next 3 months. The concentrations of plasma lipids, fatty acid (FA) profiles of phosphatidylcholine (PC), cholesteryl esters (CE) and triglycerides (TG), tHcy levels, concentrations of conjugated dienes (CD) in low-density lipoprotein (LDL), and MA were determined in baseline state, after the PUFA n-3 and placebo treatment period. Supplementation with PUFA n-3 led to a significant decrease in plasma tHcy (-29%, P < .01) and TG (-28%, P < .05) levels, as well as to a significant decrease in MA (-24%, P < .05). The decrease in MA correlated significantly with the increase in total PUFA n-3 (r = -.509, P < or = .05) and docosahexaenoic acid (r = -.52, P < .01) in TG. The concentrations of CD in LDL increased significantly (+15%, P < .05). The supplementation with PUFA n-3 to the combined statin-fibrate treatment in patients with DDL decreased the TG and tHcy levels as well as MA. It could lead to decreased risk of atherothrombosis and delay of diabetic nephropathy onset and progression.

Use of an indirect effect model to describe the LDL cholesterol-lowering effect by statins in hypercholesterolaemic patients

Statins are the most commonly prescribed agents for the treatment of hypercholesterolaemia. This is due to their efficacy in reducing low-density lipoprotein cholesterol (LDL) level which is the primary goal of the treatment especially for patients with multiple risk factors or with established coronary heart diseases. The purpose of this study was to develop a pharmacokinetic/pharmacodynamic (PK/PD) model that describes the LDL-lowering process in patients with hypercholesterolaemia treated with atorvastatin, fluvastatin or simvastatin. A total of 100 patients were studied retrospectively. They received atorvastatin (n = 57), fluvastatin (n = 26) or simvastatin (n = 17). As no pharmacokinetic data were available, the absorption rate was fixed to 1/h and atorvastatin, simvastatin and fluvastatin elimination half-lives were fixed to 14, 2 and 2.5 h respectively. A total of 309 LDL levels were measured and the data were analysed by nonmem v. The time course of the LDL-lowering effect of statins was described by an indirect-response model with precursor (LDL synthesis, input rate K(in)) and response (circulating LDL, input and output rates K) compartments. The following parameters were estimated: LDL input rate (K(in)) 0.14 +/- 0.015 g/L/day (mean +/- SD); inhibition fraction of K(in) (INH) 0.21 +/- 0.017; and dose producing 50% increase of LDL removal (D50), 26 +/- 7.8, 1.3 +/- 0.48 and 15 +/- 5.25 mg for atorvastatin, simvastatin and fluvastatin, respectively. Gender, bodyweight, age, calories/day, sugar/day, lipids/day, hyperlipidaemia types and waist/hip circumference, renal and hepatic functions had no effect on the pharmacodynamic parameters. The pharmacodynamic parameters for the three statins were accurately estimated. The PK/PD model developed successfully predicted the time course of the LDL-lowering effect of statins.

Minimizing adverse side-effects of oral bexarotene in cutaneous T-cell lymphoma: an expert opinion

Bexarotene is an oral retinoid therapy that is effective for the treatment of early and advanced-stage cutaneous T-cell lymphoma (CTCL) in patients who have failed on other therapies. However, bexarotene treatment is associated with unavoidable side-effects, in particular hypertriglyceridaemia and hypothyroidism, which are manageable with adequate concomitant medications and are reversible on cessation of treatment. A pragmatic strategy for minimizing bexarotene-associated hypertriglyceridaemia and hypothyroidism is suggested, based on data from the studies with bexarotene in CTCL and on day-to-day experience with this agent in the clinical setting. The strategy anticipates that these common adverse events are likely to occur and recommends the early use of preventive therapy to lower triglycerides and elevate thyroid hormone levels in the blood, followed by subsequent monitoring, dose adjustment during bexarotene treatment, and titration of the daily bexarotene dose from 150 to 300 mg m(-2), which is optimal for most patients. When further information becomes available on how bexarotene interacts with lipid metabolism and thyroid function, the management approach suggested here may need to be changed.

Nuclear receptors in lipid metabolism: targeting the heart of dyslipidemia

Dyslipidemia is the sine qua non of atherosclerosis, but it is also strongly associated with the metabolic syndrome, obesity, diabetes, and fatty liver disease. The molecular basis for future therapies requires understanding the pivotal role of nuclear hormone receptors in lipid and inflammatory homeostasis. This review summarizes evidence that the liver X receptor (LXR) and peroxisome proliferator-activated receptor (PPAR) are key transcriptional regulators in lipid metabolism. Additionally, their effects on glucose homeostasis and inflammation make LXR and PPAR signaling networks attractive molecular targets for managing lipid-related diseases.

Consistency of lipid-altering effects of ezetimibe/simvastatin across gender, race, age, baseline low density lipoprotein cholesterol levels, and coronary heart disease status: results of a pooled retrospective analysis

BACKGROUND

The combination tablet containing ezetimibe and simvastatin (EZE/SIMVA), inhibits both the intestinal absorption and endogenous production of cholesterol, providing significantly greater low-density lipoprotein cholesterol (LDL-C) lowering than EZE or SIMVA alone. The purpose of this pooled analysis was to evaluate the consistency of efficacy (i.e., between-treatment difference) of EZE/SIMVA versus SIMVA within several selected subgroups of patients with primary hypercholesterolemia.

METHODS

For the present analysis, data were pooled from three similarly designed, 12-week, randomized, double-blind, placebo-controlled factorial studies consisting of 3083 patients with primary hypercholesterolemia (n = 311 in placebo group; n = 302 in EZE group; n = 1234 in pooled SIMVA group; n = 1236 in pooled EZE/SIMVA group). In these clinical studies, primary hypercholesterolemia was defined as an LDL-C value between 145 and 250 mg/dL inclusive and a triglyceride (TG) level of less than 350 mg/dL. The results for the pooled SIMVA and pooled EZE/SIMVA groups were used for the present analyses. The pooled analyses focused on the consistency of the between-treatment differences (i.e., incremental effect) for EZE/SIMVA (pooled across doses) versus SIMVA (pooled across doses) on various lipid and non-lipid parameters within different patient subgroups defined according to gender, race (Caucasian, Non-Caucasian), baseline age (< 65, > or = 65 years), baseline LDL-C (< 160, > or = 160 mg/dL), and coronary heart disease (CHD) history. Tolerability was also examined for pooled EZE/SIMVA and pooled SIMVA within these selected subgroups. In a modified intention-to-treat analysis, an ANOVA model was used for testing the consistency of pooled treatment effects on lipid and non-lipid parameters within each selected subgroup.

RESULTS

For the entire cohort, baseline lipid profiles were similar for the patients in the pooled EZE/SIMVA group compared with those in the pooled SIMVA group. Treatment with EZE/SIMVA led to significant (p < 0.001) incremental improvements in LDL-C, non-high density lipoprotein cholesterol (non-HDL-C), apolipoprotein B, TG and high sensitivity C-reactive protein compared to SIMVA, across the entire cohort. These changes were consistent within each of the selected subgroups. Moreover, more patients attained LDL-C goal levels < 100 mg/dL with EZE/SIMVA than with SIMVA in the entire cohort and this was consistent across all subgroups, except baseline LDL-C. In this pooled retrospective analysis, treatment with EZE/SIMVA was generally well tolerated across subgroups, with a safety profile similar to SIMVA monotherapy. Although this pooled analysis was performed on a large cohort of patients with primary hypercholesterolemia, the results of this analysis were specific for this select patient population and generalizations to other populations should be applied with caution.

CONCLUSION

The enhanced lipid-altering effects of EZE/SIMVA versus those of SIMVA observed in the entire cohort were consistent within all subgroups examined. EZE/SIMVA represents an effective and well-tolerated therapeutic option for the treatment of a wide range of patient subgroups with primary hypercholesterolemia.

New and Emerging Strategies for Reducing Cardiometabolic Risk Factors

Several new drug therapies with beneficial effects on more than one of the cardiometabolic risk factors that contribute to the metabolic syndrome have been developed recently or are under investigation. Emerging risk factors for coronary heart disease (CHD), including low concentrations of high-density lipoprotein (HDL) cholesterol and apolipoprotein A-1 (apoA-1), high levels of high-sensitivity C-reactive protein, and small dense low-density lipoprotein cholesterol particles, have been identified. We provide a detailed description of the mechanisms of action and findings from clinical trials of the new drug therapies and discuss established drug therapies with beneficial effects on emerging risk factors for CHD. The new and emerging drug therapies include an antiobesity agent that reduces atherogenic dyslipidemia and abnormal glucose metabolism; cholesteryl ester transfer protein inhibitors that increase HDL cholesterol and apoA-1 levels; glitazars that increase HDL cholesterol and decrease triglyceride concentrations, as well as improve abnormal glucose metabolism; and the amylin analog pramlintide and the incretin mimetic exenatide, both of which reduce body weight as well as improve abnormal glucose metabolism. The insulin-sensitizing effects of angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers (ARBs), which may help prevent new-onset diabetes mellitus, and the beneficial effects of the ARB telmisartan on the glucose and lipid profiles also are presented.

Cost effectiveness of statins in coronary heart disease

INTRODUCTION

Statin therapy reduces the rate of coronary heart disease, but high costs in combination with a large population eligible for treatment ask for priority setting. Although trials agree on the size of the benefit, economic analyses of statins report contradictory results. This article reviewed cost effectiveness analyses of statins and sought to synthesise cost effectiveness ratios for categories of risk of coronary heart disease and age.

METHODS

The review searched for studies comparing statins with no treatment for the prevention of either cardiovascular or coronary heart disease in men and presenting cost per years of life saved as outcome. Estimates were extracted, standardised for calendar year and currency, and stratified by categories of risk, age, and funding source

RESULTS

24 studies were included (from 50 retrieved), yielding 216 cost effectiveness ratios. Estimated ratios increase with decreasing risk. After stratification by risk, heterogeneity of ratios is large varying from savings to $59 000 per life year saved in the highest risk category and from 6500 dollars to 490,000 dollars in the lowest category. The pooled estimates show values of 21571 dollars per life year saved for a 10 year coronary heart disease risk of 20% and 16862 dollars per life year saved for 10 year risk of 30%.

CONCLUSION

Statin therapy is cost effective for high levels of risk, but inconsistencies exist at lower levels. Although the cost effectiveness of statins depends mainly on absolute risk, important heterogeneity remains after adjusting for absolute risk. Economic analyses need to increase their transparency to reduce their vulnerability to bias and increase their reproducibility.

A retrospective analysis of ezetimibe treatment in renal transplant recipients

A retrospective review was conducted to determine the safety and efficacy of ezetimibe as a treatment option for renal transplant recipients. We evaluated the medical records of 34 adult renal transplant recipients receiving ezetimibe as monotherapy or combination therapy. Fasting lipid profiles were obtained at baseline and at 1-6 months post-ezetimibe initiation. Twenty patients received cyclosporine, 12 patients received tacrolimus, 1 patient received either sirolimus or no calcineurin therapy at the time of ezetimibe initiation. Monotherapy was started in 8 patients, who had all previously failed statins, and combination therapy was utilized in 26 patients. Monotherapy or combination therapy resulted in a mean reduction in total cholesterol of 23.3%, triglycerides 40.2%, low-density lipoproteins 16.8% and high-density lipoproteins 4.8% after 3.1 months of therapy. Ezetimibe as combination or monotherapy is a safe and effective treatment option for dyslipidemia in renal transplant recipients without changes in calcineurin inhibitor levels or renal function.

Proapoptotic and antitumor activities of the HMG-CoA reductase inhibitor, lovastatin, against Dalton's lymphoma ascites tumor in mice

BACKGROUND

Diet rich in fat have a clear effect on the tumor incidence in humans. Increased level of lipid peroxidation were found in colon, liver, breast and kidney carcinogenesis. Although the beneficial effects of statins for cardiovascular diseases are well established, their importance in the area of cancer therapeutics has recently gained recognition. Many studies of lovastatin in in vitro systems and experimental animals have been reported as an effective antitumor agent. However, phase I/II clinical trials in cancer patients demonstrated a minor to non-significant responses. Hence more studies in different tumor models using doses corresponding to that used to reduce lipid in human are required to support the antitumor activity.

METHODS

The antitumor activity was evaluated using Daltons' Lymphoma Ascites (DLA) cell line-induced ascites tumor model in mice. Proapoptotic activity was evaluated in DLA cell line induced ascites animals after the treatment of lovastatin. Apoptosis was analyzed morphologically by staining with Giemsa and biochemically by observing the laddering of DNA in agarose gel electrophoresis. In vitro cytotoxic activity of lovastatin was studied by trypan blue dye exclusion method. Lipid peroxidation inhibiting activity was demonstrated in Fe2+-ascorbate induced rat whole liver homogenate.

RESULTS

Lovastatin dose dependently inhibited the ascites tumor growth at 4 and 16 mg/kg body wt (p.o). The percentage increase in life span (%ILS) in the 16 mg/kg treated group was 61.8% (P<0.01). Single dose of lovastatin (16 mg/kg body wt, p.o) was also effective to accelerate the apoptosis in the ascites tumor bearing mice that was evident from the multiple fragmentation of DNA in gel electrophoresis. Further the morphological analysis of DLA cells aspirated from the lovastatin treated animals showed a significant (P<0.01) increase of apoptotic cells (15.5+/-3%) than the control animals (6.5+/-1%). Concentration of lovastatin required for the 50% of the cytotoxicity was 37+/-5 microg/ml. Lovastatin at its low concentrations were effective to inhibit lipid peroxidation.

CONCLUSIONS

The antitumor activity of lovastatin against the ascites tumor is due to its proapoptotic and cytotoxic activities. Lovastatin at low concentrations inhibited Fe2+ induced lipid peroxidation in in vitro system. The proapoptotic and lipid peroxidation inhibiting activities of the lipid lowering drug lovastatin may further suggest its possible therapeutic use as a cancer chemopreventive agent.

Statins in nephrotic syndrome: a new weapon against tissue injury

The nephrotic syndrome is characterized by metabolic disorders leading to an increase in circulating lipoproteins levels. Hypertriglyceridemia and hypercholesterolemia in this case may depend on a reduction in triglyceride-rich lipoproteins catabolism and on an increase in hepatic synthesis of Apo B-containing lipoproteins. These alterations are the starting point of a self-maintaining mechanism, which can accelerate the progression of chronic renal failure. Indeed, hyperlipidemia can affect renal function, increase proteinuria and speed glomerulosclerosis, thus determining a higher risk of progression to dialysis. 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase is the rate-limiting enzyme in cholesterol synthesis from mevalonate and its inhibitors, or statins, can therefore interfere with the above-mentioned consequences of hyperlipidemia. Statins are already well known for their effectiveness on primary cardiovascular prevention, which cannot be explained only through their hypolipemic effect. As far as kidney diseases are concerned, statin therapy has been shown to prevent creatinine clearance decline and to slow renal function loss, particularly in case of proteinuria, and its favorable effect may depend only partially on the attenuation of hyperlipidemia. Statins may therefore confer tissue protection through lipid-independent mechanisms, which can be triggered by other mediators, such as angiotensin receptor blockers. Possible pathways for the protective action of statins, other than any hypocholesterolemic effect, are: cellular apoptosis/proliferation balance, inflammatory cytokines production, and signal transduction regulation. Statins also play a role in the regulation of the inflammatory and immune response, coagulation process, bone turnover, neovascularization, vascular tone, and arterial pressure. In this study, we would like to provide scientific evidences for the pleiotropic effects of statins, which could be the starting point for the development of new therapeutical strategies in different clinical areas.

Vascular risk factors and erectile dysfunction in a cohort of healthy men

To determine the impact of vascular risk factors in the genesis of erectile dysfunction (ED) in a cohort of healthy men. Participants of a health-screening project were carefully selected as men without known vascular disease. Erectile dysfunction was quantified via the IIEF5-questionnaire. All men underwent a detailed health examination including determination of blood pressure, blood lipid profile and fasting serum glucose. In total 1519 men (42.9+/-7.9 years) were analysed. Age (P < 0.01), elevated levels of total cholesterol (P = 0.04) and low-density lipoproteins (LDL) (P = 0.02) were associated with moderately to severely impaired erectile function (IIEF5: <12). Men with total cholesterol >240 mg/dl had a 2.7 (1.5-4.9)-fold increased risk for moderate to severe ED, the respective figure for LDL >160 mg/dl was 2.6 (1.4-4.9). In this well characterized, healthy population, elevated serum lipids are the most important risk factors for the development of ED.

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.

GPR109A (PUMA-G/HM74A) mediates nicotinic acid-induced flushing

Nicotinic acid (niacin) has long been used as an antidyslipidemic drug. Its special profile of actions, especially the rise in HDL-cholesterol levels induced by nicotinic acid, is unique among the currently available pharmacological tools to treat lipid disorders. Recently, a G-protein-coupled receptor, termed GPR109A (HM74A in humans, PUMA-G in mice), was described and shown to mediate the nicotinic acid-induced antilipolytic effects in adipocytes. One of the major problems of the pharmacotherapeutical use of nicotinic acid is a strong flushing response. This side effect, although harmless, strongly affects patient compliance. In the present study, we show that mice lacking PUMA-G did not show nicotinic acid-induced flushing. In addition, flushing in response to nicotinic acid was also abrogated in the absence of cyclooxygenase type 1, and mice lacking prostaglandin D(2) (PGD(2)) and prostaglandin E(2) (PGE(2)) receptors had reduced flushing responses. The mouse orthologue of GPR109A, PUMA-G, is highly expressed in macrophages and other immune cells, and transplantation of wild-type bone marrow into irradiated PUMA-G-deficient mice restored the nicotinic acid-induced flushing response. Our data clearly indicate that GPR109A mediates nicotinic acid-induced flushing and that this effect involves release of PGE(2) and PGD(2), most likely from immune cells of the skin.

Beyond low-density lipoprotein: addressing the atherogenic lipid triad in type 2 diabetes mellitus and the metabolic syndrome

The metabolic syndrome and type 2 diabetes mellitus are both becoming more prevalent, and both increase the risk of cardiovascular disease. Many patients are not receiving appropriate treatment for the type of dyslipidemia that commonly occurs in these disorders--the so-called 'atherogenic lipid triad' of high serum triglyceride levels, low serum high-density lipoprotein cholesterol (HDL-C) levels, and a preponderance of small, dense, low-density lipoprotein cholesterol (LDL-C) particles. All of the processes involved in atherogenesis can be exacerbated by insulin resistance and/or the metabolic syndrome. Hypertriglyceridemia is a strong predictor of coronary heart disease. There is also an inverse relationship between serum levels of HDL-C and triglycerides in diabetic patients, with low serum HDL-C levels possibly representing an independent risk factor for cardiovascular disease. Small, dense, LDL-C particles are also highly atherogenic as they are more likely to form oxidized LDL and are less readily cleared. Insulin resistance, which is central to the metabolic syndrome and type 2 diabetes mellitus, leads to high levels of very low-density lipoprotein (VLDL), which contain a high concentration of triglycerides, resulting in high serum triglyceride levels and low serum HDL-C levels. Even though modification of the atherogenic lipid triad is probably one of the most effective methods of reducing cardiovascular risk, therapy for diabetic dyslipidemia is often directed to first lowering serum LDL-C levels with a HMG-CoA reductase inhibitor. This may leave substantial excess risk for cardiovascular disease in patients with these types of dyslipidemia. The results of recent trials evaluating HMG-CoA reductase inhibitors have been mixed, with two showing no significant effect on cardiovascular outcomes in subgroups of diabetic patients. The recent CARDS (Collaborative Atorvastatin Diabetes Study) showed that atorvastatin can reduce cardiovascular events in a trial specifically designed for a diabetic population, though the population had to have at least one other risk factor in addition to diabetes mellitus. Fibric acid derivatives, such as fenofibrate, bezafibrate and gemfibrozil, are potentially well suited to the treatment of dyslipidemia that is generally associated with type 2 diabetes mellitus and the metabolic syndrome, as they are usually more effective than HMG-CoA reductase inhibitors for normalizing serum levels of HDL-C and triglycerides. Promising results have been obtained from several trials of fibric acid derivatives including the BIP (Bezafibrate Infarction Prevention) study and the VA-HIT (Veterans Affairs Cooperative Studies Program HDL-C Intervention Trial; gemfibrozil). The FIELD (Fenofibrate Intervention and Event Lowering in Diabetes) trial, a clinical outcomes trial specifically designed to evaluate fenofibrate in a large population of patients with type 2 diabetes mellitus, many of whom have the metabolic syndrome, is underway. The FIELD trial results should shed light on the efficacy and safety of fenofibrate in reducing cardiovascular morbidity in diabetic and metabolic syndrome patients and on the safety profile of combination therapy with fenofibrate and a HMG-CoA reductase inhibitor.

Cholestanol: A serum marker to guide LDL cholesterol-lowering therapy

Statins have been the mainstay of lipid-lowering therapy since their introduction. However, as lower LDL cholesterol targets are sought, adjunct therapies are becoming increasingly important. Few patients reach new targets with statin monotherapy. We propose that the cholestanol:cholesterol ratio can be used to guide lipid-lowering therapy and result in greater numbers of patients reaching target LDL cholesterol. By determining whether a patient is mainly a synthesizer or absorber of cholesterol, customized regimens can be used and are expected to improve patient outcomes and minimize costs of treatment.

Pharmacogenomics of cholesterol-lowering therapy

The prevention of cardiovascular disease is critically dependent on lipid-lowering therapy, including 3-hydroxymethyl-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (statins), cholesterol absorption inhibitors, bile acid resins, fibrates, and nicotinic acid. Although these drugs are generally well tolerated, severe adverse effects can occur in a minority of patients. Furthermore, a subset of patients does not respond to cholesterol-lowering therapy with a reduction in coronary heart disease progression. Significant progress has been made in the identification of common DNA sequence variations in genes influencing the pharmacokinetics and pharmacodynamics of statins and in disease-modifying genes relevant for coronary heart disease (CHD). Among the most promising candidate genes for pharmacogenomic analysis of statin therapy are HMG-CoA reductase as a direct target gene and other genes modulating lipid and lipoprotein homeostasis. Based on data from pharmacogenetic trials, a combined analysis of multiple genetic variants in several genes is more likely to give significant results than single gene studies in small cohorts. In the future, pharmacogenomic testing may allow risk stratification of patients to avoid serious side effects and enable clinicians to select lipid-lowering drugs with the highest efficacy resulting in the best response to therapy.

Effectiveness of altering serum cholesterol levels without drugs

Drug therapy with statins and other agents can result in dramatic lipid-lowering effects. Despite the wealth of data supporting the beneficial effects of pharmacologic therapy on cardiovascular risk, patients often express a desire to accomplish similar goals with diet alone. And, except for patients with extreme cholesterol elevations, consensus panels all promote dietary therapy as an initial step in the treatment of hyperlipidemia. This review examines a variety of dietary strategies designed to lower lipid levels, including the American Heart Association diet, the Ornish diet, the Mediterranean diet, exercise, phytosterols, fiber, soy products, and fish oil. Though the declines in low-density lipoprotein cholesterol levels with these methods range from 0% to 37%, cardiovascular risk may be more significantly impacted than would be predicted from these changes alone. Significant benefits can be reaped from nonpharmacologic measures.

Lipid metabolism in cognitive decline and dementia

This review will focus on the current knowledge on circulating serum and plasma risk factors of cognitive decline of degenerative (Alzheimer's disease, AD) or vascular origin (vascular dementia, VaD) linked to cholesterol homeostasis and lipoprotein disturbances, i.e. total cholesterol (TC), 24S-hydroxy-cholesterol, lipoprotein(a) (Lp(a)), or apolipoprotein E (APOE). These measures linked to lipoprotein metabolism appear to be altered in AD, VaD, or predementia syndrome relative to controls, but with contrasting results. At present, several studies have demonstrated the dependence of APOE serum levels upon the APOE genotype, nonetheless serum APOE levels seems not to be a credible risk factor or a biochemical marker for AD instead of APOE genotyping. In fact, there was no consistent association of serum or plasma apoE protein levels with the disease when controlled for APOE genotype. In addition, there are some evidence that higher Lp(a) levels could be linked with AD, although there are studies suggesting an increased presence of low molecular weight apo(a) in AD, VaD, and frontotemporal dementia, that are associated with elevated Lp(a) levels. In fact, the apo(a) gene is highly polymorphic in length due to variation in the numbers of a sequence encoding the apo(a) kringle 4 domain, and plasma levels of Lp(a) are inversely correlated with apo(a) size. Furthermore, although serum/plasma levels of TC and 24S-hydroxycholesterol are not credible diagnostic markers for AD and cognitive decline, the current evidence suggests that they may be modifiable risk/protective factors. The prevailing wisdom is that high TC is a risk factor for dementia. However, the relationship between TC and dementia may vary considerably depending on when cholesterol is measured over the life course or, alternatively, in relation to the underlying course of the disease. Several observational studies have suggested that statins, which are effective in lowering cholesterol, may reduce the risk of dementia, but the results of these reports are inconclusive. Thus, more studies with long-term follow-up and serial assessments of TC are needed to further clarify the causal relationship between cholesterol and dementia.

Colesevelam HCl and ezetimibe combination therapy provides effective lipid-lowering in difficult-to-treat patients with hypercholesterolemia

This study investigated the effects of colesevelam hydrochloride (WelChol; Sankyo Pharma, Parsippany, NJ) and ezetimibe (Zetia; Merck/Schering Plough Pharmaceuticals, North Wales, PA), alone and in combination, for the treatment of hypercholesterolemia in patients who were intolerant to, or refused, HMG-Co-A reductase inhibitor (statin) therapy. Combination therapy with colesevelam HCl/ezetimibe resulted in an additional reduction in low-density lipoprotein cholesterol (LDL-C) and non-high-density lipoprotein cholesterol (HDL-C) levels of approximately 20% (P < 0.005) and 16% (P < 0.01), respectively, compared with monotherapy with either agent. Total cholesterol, LDL-C, and non-HDL-C levels were within National Cholesterol Education Program Adult Treatment Panel III target ranges at the end of the combination therapy regimen in 10 of 12 patients. In conclusion, colesevelam HCl/ezetimibe combination therapy appears to be an efficacious and well-tolerated alternative for patients with hypercholesterolemia.

An open-label, crossover study of the pharmacokinetics of Insoluble Drug Delivery®-MicroParticle fenofibrate in combination with atorvastatin, simvastatin, and extended-release niacin in healthy volunteers

BACKGROUND

Fenofibrate has been prescribed concomitantly with other lipid-lowering agents as a treatment for dyslipidemia. However, combination therapy, particularly a statin-fibrate combination, may be associated with an increased risk of myopathy, although this risk appears to be less with fenofibrate than with other fibrates.

OBJECTIVE

The objective of this study was to determine the effect of administering a single dose of atorvastatin, simvastatin, or extended-release (ER) niacin on the pharmacokinetics and safety of a single dose of fenofibrate Insoluble Drug Delivery-MicroParticle (IDD-P).

METHODS

This was an open-label, single-center,randomized, 4-treatment, 4-period crossover study in healthy adult volunteers. Subjects were randomized to 1 of 4 treatment sequences, administered 1 week apart, that included all 4 of the following treatments: 1 IDD-P fenofibrate 160-mg tablet alone; 1 IDD-P fenofibrate 160-mg tablet plus 1 atorvastatin 10-mg tablet; 1 IDD-P fenofibrate 160-mg tablet plus 1 simvastatin 10-mg tablet; and 1 IDD-P fenofibrate 160-mg tablet plus 1 ER niacin 500-mg tablet. Blood samples for pharmacokinetic analysis were obtained immediately before and up to 72 hours after administration during each of the 4 treatment periods. If the 90% CI for the log-transformed parameter was between 0.80 and 1.25, and the 90% CI for the nontransformed parameter was between 0.80 and 1.20, then the absence of a clinically significant drug interaction was assumed. However, the absence of a drug interaction was not to be ruled out if one or more of the CIs exceeded the boundary, provided the CI included 1.00.

RESULTS

Twenty healthy subjects were enrolled. Sixteen (80%) of the subjects were male and 17 (85%) were black; mean (SD) age was 35 (9.3) years. The mean C(max), AUC from the time of administration to the last quantifiable concentration (AUC(0-t)), and AUC from the time of administration to infinity (AUC(0-infinity)) were 5%, 6%, and 2% lower, respectively, with IDD-P fenofibrate plus atorvastatin than with IDD-P fenofibrate alone; the mean C(max), AUC(0-t), and AUC(0-infinity) were 6% lower, and 10% and 9% higher, respectively, with IDD-P fenofibrate plus simvastatin than with IDD-P fenofibrate alone; and the mean C(max), AUC(0-t), and AUC(0-infinity) were 12%, 6%, and 5% lower, respectively, with IDD-P fenofibrate plus ER niacin than with IDD-P fenofibrate alone. The 90% CIs surrounding the mean ratios for AUC(0-infinity) and AUC(0-infinity) for all 3 comparisons were between 0.80 and 1.25, suggesting the absence of a drug interaction for these parameters. For C(max), an absence of a drug interaction was observed between concomitantly administered IDD-P fenofibrate and both atorvastatin and simvastatin; absence of drug interaction was not found for IDD-P fenofibrate plus ER niacin. All treatments were well tolerated; headache was the most common adverse event (AE) (10%). One subject with creatinine kinase levels of 1300 IU/L (>6 times the upper limit of normal) at baseline experienced a seizure approximately 12 to approximately 13 hours after administration of IDD-P fenofibrate plus atorvastatin; this serious AE was deemed to be possibly related to study drug.

CONCLUSIONS

Concomitant administration of a single dose of either atorvastatin or simvastatin had no significant effect on the pharmacokinetics of a single dose of IDD-P fenofibrate. A drug interaction between concomitantly administered single doses of IDD-P fenofibrate and ER niacin could not be ruled out.

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.