Effects of atorvastatin versus fenofibrate on lipoprotein profiles, low-density lipoprotein subfraction distribution, and hemorheologic parameters in type 2 diabetes mellitus with mixed hyperlipoproteinemia

The Effect of Lipopolysaccharide-Stimulated Adipose-Derived Mesenchymal Stem Cells on NAFLD Treatment in High-Fat Diet-Fed Rats

Background

Nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH) are 2 common liver diseases that currently lack effective treatment options.

Objectives

This study aimed to investigate the effect of lipopolysaccharide (LPS)-stimulated adipose-derived stem cells (ADSCs) on NAFLD treatment in an animal model.

Methods

Male Wistar rats were fed a high-fat diet (HFD) to induce NAFLD for 7 weeks. The rats were then categorized into 3 groups: Mesenchymal stem cell (MSC), MSC + LPS, and fenofibrate (FENO) groups. Liver and body weight were measured, and the expression of genes involved in fatty acid biosynthesis, β-oxidation, and inflammatory responses was assessed.

Results

Lipopolysaccharide-stimulated ADSCs were more effective in regulating liver and body weight gain and reducing liver triglyceride (TG) levels compared to the other groups. Treatment with LPS-stimulated ADSCs effectively corrected liver enzymes, including alanine aminotransferase (ALT) and aspartate aminotransferase (AST), and lipid factors, including low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C) values, better than treatment with both FENO and MSCs. ADSCs + LPS treatment significantly decreased transforming growth factor β (TGF-β) and genes associated with inflammatory responses. Additionally, there was a significant reduction in reactive oxygen species (ROS) levels in the rats treated with ADSCs + LPS.

Conclusions

Lipopolysaccharide-stimulated ADSCs showed potential in alleviating NAFLD by reducing inflammatory genes and ROS levels in HFD rats, demonstrating better results than treatment with ADSCs and FENO groups alone.

Effect of PCSK9 inhibition with evolocumab on lipoprotein subfractions in familial dysbetalipoproteinemia (type III hyperlipidemia)

BACKGROUND AND AIMS

Familial dysbetalipoproteinemia (FDBL) is a rare inborn lipid disorder characterized by the formation of abnormal triglyceride- and cholesterol-rich lipoproteins (remnant particles). Patients with FDBL have a high risk for atherosclerotic disease. The effect of PCSK9 inhibition on lipoproteins and its subfractions has not been evaluated in FDBL.

METHODS

Three patients (65±7 years, 23±3 kg/m2, 2 females) with FDBL (diagnosed by isoelectrofocusing) and atherosclerosis (coronary and/or cerebro-vascular and/or peripheral arterial disease) resistant or intolerant to statin and fibrate therapy received evolocumab (140mg every 14 days). In addition to a fasting lipid profile (preparative ultracentrifugation), apoB and cholesterol concentrations were determined in 15 lipoprotein-subfractions (density gradient ultracentrifugation; d 1.006-1.21g/ml) before and after 12 weeks of evolocumab treatment. Patients with LDL-hypercholesterolemia (n = 8, 56±8 years, 31±7 kg/m2) and mixed hyperlipidemia (n = 5, 68±12 years, 30±1 kg/m2) also receiving evolocumab for 12 weeks were used for comparison.

RESULTS

All patients tolerated PCSK9 inhibition well. PCSK9 inhibitors reduced cholesterol (29-37%), non-HDL-cholesterol (36-50%) and apoB (40-52%) in all patient groups including FDBL. In FDBL, PCSK9 inhibition reduced VLDL-cholesterol and the concentration of apoB containing lipoproteins throughout the whole density spectrum (VLDL, IDL, remnants, LDL). Lipoprotein(a) was decreased in all patient groups to a similar extent.

CONCLUSIONS

This indicates that the dominant fraction of apoB-containing lipoproteins is reduced with PCSK9 inhibition, i.e. LDL in hypercholesterolemia and mixed hyperlipidemia, and cholesterol-rich VLDL, remnants and LDL in FDBL. PCSK9 inhibition may be a treatment option in patients with FDBL resistant or intolerant to statin and/or fibrate therapy.

Pravastatin and Gemfibrozil Modulate Differently Hepatic and Colonic Mitochondrial Respiration in Tissue Homogenates from Healthy Rats

Statins and fibrates are widely used for the management of hypertriglyceridemia but they also have limitations, mostly due to pharmacokinetic interactions or side effects. It is conceivable that some adverse events like liver dysfunction or gastrointestinal discomfort are caused by mitochondrial dysfunction. Data about the effects of statins and fibrates on mitochondrial function in different organs are inconsistent and partially contradictory. The aim of this study was to investigate the effect of pravastatin (statin) and gemfibrozil (fibrate) on hepatic and colonic mitochondrial respiration in tissue homogenates. Mitochondrial oxygen consumption was determined in colon and liver homogenates from 48 healthy rats after incubation with pravastatin or gemfibrozil (100, 300, 1000 μM). State 2 (substrate dependent respiration) and state 3 (adenosine diphosphate: ADP-dependent respiration) were assessed. RCI (respiratory control index)—an indicator for coupling between electron transport chain system (ETS) and oxidative phosphorylation (OXPHOS) and ADP/O ratio—a parameter for the efficacy of OXPHOS, was calculated. Data were presented as a percentage of control (Kruskal–Wallis + Dunn’s correction). In the liver both drugs reduced state 3 and RCI, gemfibrozil-reduced ADP/O (complex I). In the colon both drugs reduced state 3 but enhanced ADP/O. Pravastatin at high concentration (1000 µM) decreased RCI (complex II). Pravastatin and gemfibrozil decrease hepatic but increase colonic mitochondrial respiration in tissue homogenates from healthy rats.

CVD Risk Stratification in the PCSK9 Era: Is There a Role for LDL Subfractions?

Proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors reduce the risk of cardiovascular events and all-cause mortality in patients at high risk of cardiovascular disease (CVD). Due to high costs and unknown long-term adverse effects, critical evaluation of patients considered for PCSK9 inhibitors is important. It has been proposed that measuring low-density lipoprotein (LDL) subfractions, or LDL particle numbers (LDL-P), could be of value in CVD risk assessment and may identify patients at high risk of CVD. This review evaluates the evidence for the use of LDL subfractions, or LDL-P, when assessing CVD risk in patients for whom PCSK9 inhibitors are considered as a lipid-lowering therapy. Numerous methods for measuring LDL subfractions and LDL-P are available, but several factors limit their availability. A lack of standardization makes comparison between the different methods challenging. Longitudinal population-based studies have found an independent association between different LDL subfractions, LDL-P, and an increased risk of cardiovascular events, but definitive evidence that these measurements add predictive value to the standard risk markers is lacking. No studies have proven that these measurements improve clinical outcomes. PCSK9 inhibitors seem to be effective at lowering all LDL subfractions and LDL-P, but any evidence that measuring LDL subfractions and LDL-P yield clinically useful information is lacking. Such analyses are currently not recommended when considering whether to initiate PCKS9 inhibitors in patients at risk of CVD.

Management of Lipids in Patients with Diabetes

Abnormal lipids, sometimes referred to as diabetes dyslipidemia, is a common condition in patients with diabetes. With the increasing number of patients with abnormal lipids, especially those with type 2 diabetes, health care practitioners, including nurses, have to properly manage patients with diabetes as well as abnormal lipids. This article examines the pathophysiology of abnormal lipids, the management of abnormal lipids, and the lipid goals for patients with diabetes. Lastly, this article discusses pharmacologic and nonpharmacologic therapies and the role of primary care providers and nurses in the management of abnormal lipids.

Atherogenic Lipoprotein Subfractions Determined by Ion Mobility and First Cardiovascular Events After Random Allocation to High-Intensity Statin or Placebo: The Justification for the Use of Statins in Prevention: An Intervention Trial Evaluating Rosuvastatin (JUPITER) Trial

BACKGROUND

Cardiovascular disease (CVD) can occur in individuals with low low-density lipoprotein (LDL) cholesterol (LDL-C). We investigated whether detailed measures of LDL subfractions and other lipoproteins can be used to assess CVD risk in a population with both low LDL-C and high C-reactive protein who were randomized to high-intensity statin or placebo.

METHODS AND RESULTS

In 11 186 Justification for the Use of Statins in Prevention: An Intervention Trial Evaluating Rosuvastatin (JUPITER) participants, we tested whether lipids, apolipoproteins, and ion mobility-measured particle concentrations at baseline and after random allocation to rosuvastatin 20 mg/d or placebo were associated with first CVD events (n=307) or CVD/all-cause death (n=522). In placebo-allocated participants, baseline LDL-C was not associated with CVD (adjusted hazard ratio [HR] per SD, 1.03; 95% confidence interval [CI], 0.88-1.21). In contrast, associations with CVD events were observed for baseline non-high-density lipoprotein (HDL) cholesterol (HR, 1.18; 95% CI, 1.01-1.38), apolipoprotein B (HR, 1.28; 95% CI, 1.11-1.48), and ion mobility-measured non-HDL particles (HR, 1.19; 95% CI, 1.05-1.35) and LDL particles (HR, 1.21; 95% CI, 1.07-1.37). Association with CVD events was also observed for several LDL and very-low-density lipoprotein subfractions but not for ion mobility-measured HDL subfractions. In statin-allocated participants, CVD events were associated with on-treatment LDL-C, non-HDL cholesterol, and apolipoprotein B; these were also associated with CVD/all-cause death, as were several LDL and very-low-density lipoprotein subfractions, albeit with a pattern of association that differed from the baseline risk.

CONCLUSIONS

In JUPITER, baseline LDL-C was not associated with CVD events, in contrast with significant associations for non-HDL cholesterol and atherogenic particles: apolipoprotein B and ion mobility-measured non-HDL particles, LDL particles, and select subfractions of very-low-density lipoprotein particles and LDL particles. During high-intensity statin therapy, on-treatment levels of LDL-C and atherogenic particles were associated with residual risk of CVD/all-cause death.

CLINICAL TRIAL REGISTRATION

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

Statins, fibrates, thiazolidinediones and resveratrol as adjunctive therapies in sepsis: could mitochondria be a common target?

Through their pleiotropic actions, statins, fibrates, thiazolidinediones and resveratrol can target multiple mechanisms involved in sepsis. Their actions on mitochondrial function are of interest in a pathological state where bioenergetic failure may play a key role in the development of organ dysfunction. We review these four drug groups as potential adjunctive therapies in sepsis with a particular focus upon mitochondria. Systematic review of clinical and experimental trials was done with a literature search using the PubMed database. Search terms included statins, fibrates, thiazolidinediones, resveratrol, mitochondria, sepsis, peroxisome proliferator-activated receptors, inflammation, oxidative stress and organ dysfunction. With the exception of statins, most of the compelling evidence for the use of these agents in sepsis comes from the experimental literature. The agents all exert anti-inflammatory and anti-oxidant properties, plus protective effects against mitochondrial dysfunction and stimulation of mitochondrial biogenesis. Improved outcomes (organ dysfunction, survival) have been reported in a variety of sepsis models. Notably, positive outcome effects were more commonly seen when the agents were given as pre- rather than post-treatment of sepsis. Statins, fibrates, thiazolidinediones and resveratrol prevent sepsis-induced injury to organs and organelles with outcome improvements. Their effects on mitochondrial function may be integral in offering this protection. Definitive clinical trials are needed to evaluate their utility in septic patients or those at high risk of developing sepsis.

Effects of atorvastatin 10 mg and fenofibrate 200 mg on the low-density lipoprotein profile in dyslipidemic patients: A 12-week, multicenter, randomized, open-label, parallel-group study

BACKGROUND

Elevated plasma low-density lipoprotein cholesterol (LDL-C) concentrations are highly atherogenic, especially the small, dense LDL (sdLDL) species. Fenofibrate has been reported to shift the LDL profile by decreasing the sdLDL subfraction and increasing larger LDL subclasses. Atorvastatin, anantihyperlipidemic agent, has been reported to reduce plasma total cholesterol (TC) and triglyceride (TG) concentrations and thus could modify the LDL profile.

OBJECTIVE

The aim of this study was to compare the effects of fenofi brate and atorvastatin on standard lipid concentrations and the LDL profile.

METHODS

In this randomized, open-label, parallel-group study, men and women aged 18 to 79 years with type II primary dyslipidemia, defined as LDL-C ≥160 and TG 150 to 400 mg/dL, after a 4- to 6-week washout period while eating an appropriate diet, were randomized to receive either atorvastatin 10 mg once daily or fenofi-brate 200 mg once daily. Plasma lipid concentrations and cholesterol and apolipoprotein (apo) B (reflecting the LDL particle number) in each LDL subfraction prepared by ultracentrifiigation were determined at baseline and after 12 weeks of treatment. Tolerability was assessed using adverse events (AEs) obtained on laboratory analysis and vital sign measurement. Adherence was assessed by counting unused drug supplies.

RESULTS

A total of 165 patients (117 men, 48 women; mean [SD] age, 50.1 [10.7] years; mean TC concentration, 289 mg/dL) were randomized to receive atorvastatin (n = 81) or fenofibrate (n = 84). Compared with fenofibrate, atorvastatin was associated with a significantly greater mean (SD) percentage decrease in TC (27.0% [12.3%] vs 16.5% [12.9%]; P < 0.001), calculated LDL-C (35.4% [15.8%] vs 17.3% [17.2%]; P < 0.001), TC/high-density lipoprotein cholesterol (HDL-C) ratio (29.1% [16.3%] vs 22.9% [15.9%]; P = 0.001), and apoB (30.3% [12.7%] vs 19.6% [15.5%]; P < 0.001). Compared with atorvastatin, fenofibrate was associated with a significantly greater decrease in TG (37.2% [25.9%] vs 20.2% [27.3%]; P < 0.001) and a significantly greater increase in HDL-C concentration (10.4% [15.7%] vs 4.6% [12.1%]; P = 0.017). Fibrinogen concentration was significantly different between the 2 groups (P = 0.002); it was decreased with fenofibrate use (4.6% [23.7%]) and was increased with atorvastatin use (5.7% [23.5%]). Atorvastatin did not markedly affect the LDL distribution; it was associated with a homogeneous decrease in cholesterol and apoB concentrations in all subfractions, whereas fenofibrate was associated with a marked movement toward a normalized LDL profile, shifting the sdLDL subfractions toward larger and less atherogenic particles, particularly in those patients with baseline TG ≥200 mg/dL. No serious AEs related to the study treatments were reported. A total of 5 AEs were observed in 8 patients, including: abdominal pain, 3 patients (2 in the atorvastatin group and 1 in the fenofibrate group); abnormal liver function test results, 1 (fenofibrate); increased creatine Phosphokinase activity, 2 (atorvastatin); gastrointestinal disorders, 1 (fenofibrate); and vertigo, 1 (fenofibrate).

CONCLUSION

In these dyslipidemic patients, fenofibrate treatment was associated with an improved LDL subfraction profile beyond reduction in LDL-C, particularly in patients with elevated TG concentration, whereas atorvastatin was associated with equally reduced concentrations of cholesterol and apoB in all LDL subfractions independent of TG concentrations.

A comparative study of efficacy of atorvastatin alone and its combination with fenofibrate on lipid profile in type 2 diabetes mellitus patients with hyperlipidemia

Mixed dyslipidemia is characterized by increased low-density lipoprotein cholesterol (LDL-C) elevated triglycerides (TGs) and decrease high-density lipoprotein cholesterol (HDL-C). It is more common in diabetes and is associated with an increased risk of coronary artery disease. Monotherapy with statins or fibrates may not effectively control all lipid parameters. The atorvastatin-fenofibrate combination has been shown to have highly beneficial effect on lipid parameters in type 2 diabetes associated with combined hyperlipidemia (CHL). In an open-label study, we evaluated the efficacy of atorvastatin alone and in combination with fenofibrate in 60 types 2 diabetes mellitus patients associated with hyperlipidemia. Patients were randomly assigned to receive atorvastatin 10 mg (Group 1) or combination of atorvastatin 10 mg and fenofibrate 145 mg (Group 2) once daily for 12 weeks. The effect of drugs on lipid profile was evaluated before and after treatment. After 12 weeks, the reduction in total cholesterol (TC), TGs, LDL-C, VLDL-C was 28%, 20%, 37% and 20% in Group 1 (P < 0.001 for all) as compared with 31%, 39%, 33% and 40% in Group 2 (P < 0.001 for all). There was insignificant rise in HDL-C in Group 1 (P = 0.71) and insignificant decrease in HDL-C (P = 0.70) in Group 2. During the combination therapy, the decrease in TC, TGs and VLDL-C was greater than atorvastatin alone. The combination of atorvastatin with fenofibrate in type 2 diabetes patients with CHL may have a favorable effect on some major coronary artery disease risk factors.

Epanova® and hypertriglyceridemia: pharmacological mechanisms and clinical efficacy

While LDL-cholesterol lowering has become the cornerstone of cardiovascular risk reduction strategies, considerable interest in additional targeting of hypertriglyceridemia continues. While ω-3 fatty acids are commonly used in clinical practice for triglyceride lowering, no large-scale clinical trial evaluating their impact on clinical events has been performed. As a result, there remains a lack of consensus with regards to their optimal clinical use. Epanova® (Omthera Pharmaceuticals Inc., NJ, USA) is a novel ω-3 free fatty acid formulation, developed to maximize eicosapentenoic acid and docosahexenoic acid bioavailability with low-fat diets, suggesting a potential therapeutic advantage compared with ω-3-acid ethyl esters in the treatment of patients with hypertriglyceridemia. Additional human studies are needed to define more clearly the cellular and molecular basis for the triglyceride-lowering effects of Epanova and this drug’s favorable cardiovascular effects, particularly in patients with hypertriglyceridemia.

Effects of the PPAR-δ agonist MBX-8025 on atherogenic dyslipidemia

OBJECTIVE

Determine the effects of treatment with a selective PPAR-δ agonist±statin on plasma lipoprotein subfractions in dyslipidemic individuals.

METHODS

Ion mobility analysis was used to measure plasma concentrations of subfractions of the full spectrum of lipoprotein particles in 166 overweight or obese dyslipidemic individuals treated with the PPAR-δ agonist MBX-8025 (50 and 100 mg/d)±atorvastatin (20 mg/d) in an 8-week randomized parallel arm double blind placebo controlled trial.

RESULTS

MBX-8025 at both doses resulted in reductions of small plus very small LDL particles and increased levels of large LDL, with a concomitant reduction in large VLDL, and an increase in LDL peak diameter. This translated to reversal of the small dense LDL phenotype (LDL pattern B) in ∼90% of the participants. Modest increases in HDL particles were confined to the smaller HDL fractions. Atorvastatin monotherapy resulted in reductions in particles across the VLDL-IDL-LDL spectrum, with a significantly smaller reduction in small and very small LDL vs. MBX-8025 100 mg/d (-24.5±5.3% vs. -47.8±4.9%), and, in combination with MBX-8025, a reversal of the increase in large LDL.

CONCLUSION

PPAR-δ and statin therapies have complementary effects in improving lipoprotein subfractions associated with atherogenic dyslipidemia.

Residual microvascular risk in diabetes: unmet needs and future directions

The burden of microvascular disease in patients with type 2 diabetes mellitus continues to escalate worldwide. Current standards of care reduce but do not eliminate the risk of diabetic retinopathy, nephropathy or neuropathy in these patients. Correction of atherogenic dyslipidemia, which is characterized by elevated triglyceride levels and low levels of HDL cholesterol, might provide additional benefit. Whereas promising data have been published with respect to fibrate therapy for maculopathy, fenofibrate for diabetic retinopathy, and statin or fibrate therapy for diabetic nephropathy, further studies are warranted to define optimal management strategies for reducing the residual microvascular risk. Such strategies are especially relevant in cases of diabetic peripheral neuropathy, where even optimal care fails to affect disease progression. Identification of those factors that are most relevant to residual diabetes-related microvascular risk is a priority of an ongoing multinational epidemiological study. In this Review, we highlight an urgent need to address the issue of microvascular residual risk in patients with or at risk of type 2 diabetes mellitus.

Evaluation of lipid profiles and the use of omega-3 essential Fatty Acid in professional football players

BACKGROUND

Recent research showed 82% of 233 retired National Football League players under age 50 had abnormal narrowing and blockages in arteries compared to the general population of the same age. It has been suggested that early screening and intervention in this at-risk population be a priority.

HYPOTHESIS

Omega-3 essential fatty acid has been shown to improve cardiovascular lipid risk factors and should improve lipid profiles in professional football players to help reduce their recently shown accelerated risk of developing cardiovascular disease.

METHODS

A total of 36 active national football players were randomly assigned to 2 groups: the first group (n = 20) was provided fish oil capsules (2200 mg of mixed docosahexaenoic acid and eicosapentaenoic acid and 360 mg of other omega-3s), and the second group (n = 16) served as controls during a 60-day trial. Vertical Auto Profile cholesterol tests directly measuring serum low-density lipoprotein, high-density lipoprotein, and other subfractions were performed. Compliance, side effects, and seafood consumption data were also collected. Baseline, midpoint, and poststudy blood work measured plasma docosahexaenoic acid and eicosapentaenoic acid.

RESULTS

Treatment increased high-density lipoprotein (average percent change: +25.96, control +14.16), decreased triglycerides treatment (-8.06, control +43.98), very low-density lipoprotein treatment (-13.98, control +23.18), intermediate density lipoprotein (-27.58, control +12.07), remnant lipoproteins (-23.86, control +8.33), and very low-density lipoprotein-3 (-17.10, control +7.77). An average increase of 106.67% for docosahexaenoic acid and 365.82% for eicosapentaenoic acid compared to control was also shown.

CONCLUSION

Omega-3 supplementation significantly improved the lipid profile of active players randomized to treatment. These results suggest that fish oil supplementation is an effective way to increase eicosapentaenoic acid and docosahexaenoic acid levels in plasma and should be considered as a method to improve modifiable cardiovascular risk lipid factors in professional football players.

CLINICAL RELEVANCE

A prospective study examining the effects of 60 days of a highly purified fish oil supplementation in professional football players.

Statins but not fibrates improve the atherogenic to anti-atherogenic lipoprotein particle ratio: a randomized crossover study

BACKGROUND

Prior studies suggested low density lipoprotein particle (LDLP) size is a predictor of atherosclerosis. Knowledge of effects of lipid lowering drugs on lipoprotein subclasses is useful. We treated subjects with hyperlipidemia sequentially with statins and fibrates, the 2 main classes of lipid lowering therapy and studied changes in NMR lipoprotein subclasses.

METHODS

35 subjects (21 males; 60 +/- 12 y) were enrolled in a crossover study. Subjects had baseline lipid profile & apoB. Lipoprotein subclasses, particle numbers and diameters were assessed with NMR spectroscopy. Subjects were randomized to simvastatin 20 mg or fenofibrate 200 mg. Repeat testing was done at 12 weeks. After 6 week washout, subjects were started on alternate drug for 12 weeks with pre/post tests.

RESULTS

Both therapies resulted in expected changes in lipids and apoB. Decreases in total cholesterol, LDL and apoB were greater with simvastatin. Fenofibrate led to small increase in HDL. Both therapies decreased LDLP. Reduction in LDLP was greater with simvastatin (32%, p < .001) compared to fenofibrate (17%; p = .036 vs pre; p = .027 vs simvastatin end). Fenofibrate resulted in 17% rise in large LDLP (p = .06 vs pre) and 32% drop in small LDLP (p = .007 vs pre). Simvastatin led to decrease in both LDLP fractions (19% large LDLP; p = .001 vs fenofibrate end; 34% small LDLP, p = .019 vs pre). With fenofibrate, LDLP size increased from 20.4 nm to 20.8 nm (p = .037). There was no change in LDLP size with simvastatin. There was 18% increase in HDL particle number (HDLP) with fenofibrate (p = .05). There were no changes in HDLP with simvastatin. There were no changes in HDLP size with either drug. Pre- and post-therapy LDLP/HDLP ratio was similar with fenofibrate but was reduced by simvastatin (p = .045).

CONCLUSION

Simvastatin reduced LDLP across all subclasses with no effect on size. Simvastatin had no effect on HDLP. Fenofibrate had weak effect on LDLP number but increased LDLP size by raising large LDLP and reducing small LDLP. Fenofibrate had weak effect on HDLP number with no change in size. Importantly, net atherogenic to antiatherogenic lipoprotein ratio (LDLP/HDLP) was reduced by simvastatin but not by fenofibrate.

The differential effects of thiazolidindiones on atherogenic dyslipidemia in type 2 diabetes: what is the clinical significance?

BACKGROUND

Diabetic dyslipidemia is typically characterized by an increase in plasma triglycerides, a decrease in high-density lipoprotein cholesterol and a concomitant increase in atherogenic small dense low-density lipoproteins. Thiazolidindiones are able to lower the levels of fasting glucose and glycated hemoglobin significantly by improving insulin sensitivity, as well as improving some aspects of diabetic dyslipidemia: total cholesterol, low-density lipoprotein cholesterol and high-density lipoprotein cholesterol tend to increase while triglycerides are generally decreased.

OBJECTIVE

This paper reviewed the effects of pioglitazone and rosiglitazone on atherogenic diabetic dyslipidemia, in particular on small dense low-density lipoprotein particles.

METHODS

A literature search (by Medline and Scopus) was performed up to 15 March 2008. The authors also manually reviewed the references of selected articles for any pertinent material.

RESULTS

Pioglitazone showed an additional beneficial effect on triglycerides, high-density lipoprotein cholesterol and the levels of small dense low-density lipoprotein compared to rosiglitazone.

CONCLUSIONS

Since recent studies have suggested that these agents may also have a differential effect on long-term cardiovascular end-points despite similar improvements in glycated hemoglobin and insulin sensitivity, the different impact on atherogenic diabetic dyslipidemia may help to explain these findings.

Activation of peroxisome proliferator-activated receptor-alpha in mice induces expression of the hepatic low-density lipoprotein receptor

Background and purpose:

Mutations in the low-density lipoprotein receptor (LDLR) gene cause familial hypercholesterolaemia in humans and deletion of the LDLR induces lesion development in mice fed a high-fat diet. LDLR expression is predominantly regulated by sterol regulatory element-binding protein 2 (SREBP2). Fenofibrate, a peroxisome proliferator-activated receptor α (PPARα) ligand, belongs to a drug class used to treat dyslipidaemic patients. We have investigated the effects of fenofibrate on hepatic LDLR expression.

Experimental approach:

The effects of fenofibrate on hepatic LDLR expression (mRNA and protein) and function were evaluated by both in vitro (with AML12 cells) and in vivo experiments in mice.

Key results:

Fenofibrate increased LDLR expression and LDL binding in a mouse hepatoma cell line, AML12 cells. Fenofibrate restored sterol-inhibited hepatocyte LDLR expression. Mechanistic studies demonstrated that induction of LDLR expression by fenofibrate was dependent on PPARα and sterol regulatory elements (SRE). Specifically, fenofibrate induced LDLR expression by increasing maturation of SREBP2 and phosphorylation of protein kinase B (Akt) but had no effect on SREBP cleavage-activating protein. In vivo, a high-fat diet suppressed LDLR expression in mouse liver while elevating total and LDL cholesterol levels in plasma. However, fenofibrate restored LDLR expression inhibited by high-fat diets in the liver and reduced LDL cholesterol levels in plasma.

Conclusions and implications:

Our data suggest that fenofibrate increased hepatic LDLR expression in mice by a mechanism involving Akt phosphorylation and LDLR gene transcription mediated by SREBP2.

Atorvastatin monotherapy vs. combination therapy in the management of patients with combined hyperlipidemia

BACKGROUND

Mixed hyperlipidemia is a common disorder characterized by elevated VLDL and LDL levels. Patients with this syndrome usually are in need of combination therapy, comprising a fibric acid derivate with a statin drug in order to achieve LDL and triglyceride target values. Atorvastatin is a hydroxymethylglutaryl coenzyme A (HMG-CoA) reductase inhibitor demonstrated to be effective in reducing both cholesterol (CHOL) and triglyceride (TG) levels in humans. We examined the efficacy of atorvastatin as monotherapy in achieving a better or the same lipid profile in patients with mixed hyperlipidemia treated with combination therapy.

DESIGN

We compared atorvastatin with a combination of a fibric acid derivate and a statin drug (other than atorvastatin) in a 24-week, prospective randomized, open-label study of 27 patients with mixed hyperlipidemia.

METHODS

All 27 patients had been treated with statin-fibrate therapy in different regimens for at least a year. Atorvastatin at a daily dose of 20 mg was substituted for statin-fibrate therapy. Lipid and safety profiles were assessed.

RESULTS

Atorvastatin significantly reduced total cholesterol, LDL-C, and HDL-C compared to statin-fibrate therapy. In contrast, TG and glucose levels were significantly elevated with atorvastatin. Target LDL-C and TG was achieved in 10 patients with the single therapy of atorvastatin vs. 6 patients under statin-fibrate. In 16 patients, atorvastatin was at least as effective as, or better than, the combination therapy, and was recommended for continuation of treatment.

CONCLUSION

Atorvastatin is an adequate monotherapy for many mixed hyperlipidemia patients. We recommend atorvastatin be considered for every patient suffering from mixed hyperlipidemia.

Differential effect of fenofibrate and atorvastatin on in vivo kinetics of apolipoproteins B-100 and B-48 in subjects with type 2 diabetes mellitus with marked hypertriglyceridemia

The specific impact of 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors and fibrates on the in vivo metabolism of apolipoprotein (apo) B has not been systematically investigated in patients with type 2 diabetes mellitus with high plasma triglyceride (TG) levels. Therefore, the objective of this 2-group parallel study was to examine the differential effects of a 6-week treatment with atorvastatin or fenofibrate on in vivo kinetics of apo B-48 and B-100 in men with type 2 diabetes mellitus with marked hypertriglyceridemia. Apolipoprotein B kinetics were assessed at baseline and at the end of the intervention using a primed constant infusion of [5,5,5-D(3)]-l-leucine for 12 hours in the fed state. Fenofibrate significantly decreased plasma TG levels with no significant change in plasma low-density lipoprotein cholesterol (LDL-C) and apo B levels. On the other hand, atorvastatin significantly reduced plasma levels of TG, LDL-C, and apo B. After treatment with fenofibrate, very low-density lipoprotein (VLDL) apo B-100 pool size (PS) was decreased because of an increase in the fractional catabolic rate (FCR) of VLDL apo B-100. No significant change was observed in the kinetics of LDL apo B-100. Moreover, fenofibrate significantly decreased TG-rich lipoprotein (TRL) apo B-48 PS because of a significant increase in TRL apo B-48 FCR. After treatment with atorvastatin, VLDL and IDL apo B-100 PSs were significantly decreased because of significant elevations in the FCR of these subfractions. Low-density lipoprotein apo B-100 PS was significantly lowered because of a tendency toward decreased LDL apo B-100 production rate (PR). Finally, atorvastatin reduced TRL apo B-48 PS because of a significant decrease in the PR of this subfraction. These results indicate that fenofibrate increases TRL apo B-48 as well as VLDL apo B-100 clearance in men with type 2 diabetes mellitus with marked hypertriglyceridemia, whereas atorvastatin increases both VLDL and IDL apo B-100 clearance and decreases TRL apo B-48 and LDL apo B-100 PR.

Comparison of atorvastatin versus fenofibrate in reaching lipid targets and influencing biomarkers of endothelial damage in patients with familial combined hyperlipidemia

Statins and fibrates have different effects on lipid abnormalities of familial combined hyperlipidemia (FCHL); thus, the selection of the first-line drug is troublesome. We evaluated to what extent monotherapy with a potent statin is more effective than fibrate in reaching the recommended lipid targets in FCHL. Fifty-six patients were randomized to receive optimal dosage of atorvastatin (n = 27) or 200 mg/d micronized fenofibrate (n = 29) for 24 weeks. To reach the optimal dosage, atorvastatin was up-titrated at each follow-up visit if low-density lipoprotein (LDL) cholesterol >130 mg/dL (>100 mg/dL in patients with coronary or cerebrovascular disease). The effects of fenofibrate and atorvastatin on lipoprotein fractions as well as on plasma levels of endothelin-1 (ET-1) and adrenomedullin (AM) were also evaluated. At end of trial, a greater proportion of patients on atorvastatin (average dosage, 20.8 mg/d) reached lipid targets in comparison with those on fenofibrate (64% vs 32.1%, P = .02). Atorvastatin was significantly more effective in reducing total cholesterol, LDL cholesterol, apolipoprotein B, and non-high-density lipoprotein (HDL) cholesterol. Conversely, triglycerides decreased and HDL increased more during fenofibrate. Nevertheless, atorvastatin produced a marked reduction in very low-density lipoprotein and very low-density lipoprotein remnants. Atorvastatin lowered all LDL subtypes, although fenofibrate appeared to be more effective on denser LDL. Compared with 43 normolipemic controls, FCHL patients presented increased baseline plasma levels of ET-1 (P = .007) but not of AM. Fenofibrate, but not atorvastatin, significantly lowered ET-1 levels by 16.7% (P < .05). Neither drug significantly affected plasma concentrations of AM. In summary, although fenofibrate showed superiority in raising HDL and reducing ET-1, atorvastatin was more effective in reaching lipid targets in FCHL so that it can be proposed as the first-line option in the management of this atherogenic hyperlipidemia.

A double-blind, randomised trial of tesaglitazar versus pioglitazone in patients with type 2 diabetes mellitus

The efficacy and safety of tesaglitazar (0.5 and 1 mg) and pioglitazone (15, 30 and 45 mg) were compared in a 24-week, randomised, double-blind study in 1,707 patients with type 2 diabetes mellitus. Tesaglitazar 1 mg was non-inferior to pioglitazone 45 mg for change from baseline in glycosylated haemoglobin (HbA1C) at 24 weeks (difference: -0.056 [95% confidence intervals -0.161, 0.049], pNI<0.001 for non-inferiority hypothesis). Tesaglitazar 1 mg improved triglyceride (TG), high-density lipoprotein cholesterol (HDL-C) and non-HDL-C levels compared with all pioglitazone doses at 24 weeks (p<0.001). Low-density lipoprotein cholesterol (LDL-C) was lower with tesaglitazar for all pioglitazone comparisons (p<0.05), except for tesaglitazar 0.5 mg versus pioglitazone 15 mg. Tesaglitazar 1 mg decreased LDL particle number, when compared with all pioglitazone doses (p<0.01). Both agents increased body weight and peripheral oedema in a dose-dependent manner, but only tesaglitazar increased serum creatinine. In summary, tesaglitazar provided similar glycaemic control to pioglitazone, was associated with significant improvement in lipid and lipoprotein variables, and increased serum creatinine in a dose-dependent manner.

Short-term therapy with atorvastatin or fenofibrate does not affect plasma ghrelin, resistin or adiponectin levels in type 2 diabetic patients with mixed hyperlipoproteinaemia

Lipid-lowering therapy is associated with reduced cardiovascular risk. The aim of the present study was to investigate whether lipid-lowering therapy might be associated with changes in the concentrations of metabolically important hormone concentrations. We performed a randomised cross-over open-label trial with atorvastatin (10 mg/day) and fenofibrate (200 mg/day), each for 6 weeks separated by a 6-week washout period in 13 patients (5 men, 8 women, age 60.0+/-6.8 years, body mass index 30.0+/-3.0 kg/m2) with type 2 diabetes mellitus and mixed hyperlipoproteinaemia. Plasma ghrelin (RIA, Phoenix Pharmaceuticals, Mountain View, CA, USA), adiponectin (ELISA, Biovendor, Heidelberg, Germany) as well as resistin (ELISA, Linco Research, St. Charles, MO, USA) concentrations were measured before and after atorvastatin as well as before and after fenofibrate. Ghrelin (462+/-84 pg/ml before vs. 464+/-102 pg/ml after atorvastatin, n.s.; 454+/-85 pg/ml before vs. 529+/-266 pg/ml after fenofibrate, n.s.), resistin (24.4+/-7.4 pg/ml before vs. 23.7+/-9.1 pg/ml after atorvastatin, n.s.; 23.4+/-8.2 pg/ml before vs. 19.9+/-5.5 pg/ml after fenofibrate, n.s.), adiponectin (10.89+/-5.33 pg/ml before vs. 12.41+/-5.75 pg/ml after atorvastatin, n.s.; 12.58+/-9.87 pg/ml before vs. 10.27+/-5.23 pg/ml after fenofibrate, n.s.) and insulin levels did not change significantly during lipid-lowering therapy. In patients with type 2 diabetes and mixed hyperlipoproteinaemia, short-term atorvastatin as well as fenofibrate therapy had no significant effects on adiponectin, ghrelin or resistin levels.

The clinical significance of the size of low-density-lipoproteins and the modulation of subclasses by fibrates

BACKGROUND

Beyond total low-density-lipoproteins (LDL) levels, increasing evidence suggests that the 'quality' of LDL exerts a great influence on the cardiovascular risk. Several studies have also shown that the therapeutic modulation of LDL size is of benefit in reducing the risk of cardiovascular events. Hypolipidaemic treatment is able to alter LDL subclass distribution but strong variations have been noticed among different agents. Fibrates have a major impact on triglyceride metabolism and in modulating LDL size and subclasses, but variations exist among the different molecules.

METHODOLOGY

A literature search (by Medline and Scopus) was performed using the following headings: 'small dense LDL', 'LDL size', 'LDL subfractions', 'LDL subclasses', 'LDL distribution' and 'fenofibrate', 'bezafibrate', 'ciprofibrate' and 'gemfibrozil' up to 20 January 2007. The authors also manually reviewed the references of selected articles for any pertinent material.

RESULTS

Analysis of all published studies revealed that treatment with fenofibrate, ciprofibrate, bezafibrate and gemfibrozil is usually beneficial, and fenofibrate may be more efficacious than the other molecules. This is supported by using all the available techniques in subjects with a very wide range of lipid alterations.

CONCLUSION

Among the different agents, fenofibrate has been found to be particularly effective in modulating LDL size and subclasses in patients at higher cardiovascular risk, such as those with type 2 diabetes or the metabolic syndrome.

Effects of statins, fibrates, rosuvastatin, and ezetimibe beyond cholesterol: the modulation of LDL size and subclasses in high-risk patients

Increasing evidence suggests that the quality-rather than just the quantity-of low-density lipoproteins (LDLs) exerts a great influence on cardiovascular risk. LDLs comprise multiple subclasses with discrete size and density, and different physicochemical composition, metabolic behaviors, and atherogenicity. Individuals generally cluster into 2 broad subgroups. Most have a predominance of large LDLs, and some have a higher proportion of small particles. Small, dense LDLs are good predictors of cardiovascular events and progression of coronary artery disease. Their predominance has been accepted as an emerging cardiovascular risk factor by the National Cholesterol Education Program Adult Treatment Panel III. Several studies have shown that therapeutic modulation of LDL size and subclass is of great benefit in reducing the risk of cardiovascular events. This seems particularly true for statins and fibrates when they are administered to higher-risk patients, such as those with type 2 diabetes or vascular disease. Data reporting outcomes with the use of rosuvastatin, the latest statin molecule introduced to the market, and ezetimibe, a cholesterol absorption inhibitor, are promising.

Fibrates: What Have We Learned in the Past 40 Years?

The prominent use of fibric acid derivatives has lessened over the years because of unimpressive results in major clinical trials, safety concerns, and the emergence of 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins). Clofibrate was widely used in the 1970s, but after publication of results from two major trials demonstrating only modest reductions in the rate of coronary heart disease (CHD) and concerns regarding an increase in the frequency of gallstones and overall mortality, its use subsided dramatically. With the introduction of gemfibrozil in the 1980s came a renewed interest in the class, which was also supported by the published results of the Helsinki Heart Study; however, despite a significant reduction in CHD events and a sound safety profile, overall mortality was comparable to that with placebo. Again, in the 1990s, awareness of the fibrates was heightened with the availability of fenofibrate and the findings of another major trial using gemfibrozil, the Veterans Affairs High-Density Lipoprotein Cholesterol Intervention Trial (VA-HIT), which demonstrated impressive results in reducing cardiovascular events. To further strengthen the VA-HIT results, numerous post hoc analyses were performed on the data of major trials of fibrate therapy among patients with mixed dyslipidemia, with similar findings. Recently, however, data from the Fenofibrate Intervention and Event Lowering in Diabetes (FIELD) study were published, indicating mixed results. Nearly 40 years after the introduction of the fibrates, practitioners are still contemplating the role of these agents in the treatment of CHD.

Inflammation in diabetes mellitus: role of peroxisome proliferator-activated receptor-alpha and peroxisome proliferator-activated receptor-gamma agonists

Patients with type 2 diabetes mellitus and/or the metabolic syndrome have considerable cardiovascular risk. Treatment with 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) and with antihypertensive and some antihyperglycemic agents reduces this risk, but residual macrovascular morbidity and mortality persist, even in patients assigned to intensive multifactorial intervention programs. Therapeutic strategies that target inflammation and lipid abnormalities not well addressed by statins may offer additional opportunities for improving the prognosis of these patients. Inflammation, a key mechanism of atherogenesis, appears to have particular relevance to diabetic vascular complications, as well as in the development of diabetes itself. Oxidative stress and hyperglycemia also figure among the pathogenic factors that promote cardiovascular complications in patients with the metabolic syndrome and/or diabetes and may augment the ongoing inflammation. Peroxisome proliferator-activated receptor (PPAR)-alpha and PPAR-gamma, members of the nuclear receptor family, form ligand-activated transcription factors that regulate key important metabolic pathways. PPARs have become therapeutic targets through the use of the fibrate class of antidyslipidemic drugs (PPAR-alpha) and the insulin-sensitizing thiazolidinediones (PPAR-gamma). The activation of these PPARs may also suppress inflammation and atherosclerosis. Recent clinical trials (Fenofibrate Intervention and Event Lowering in Diabetes [FIELD], Prospective Pioglitazone Clinical Trial in Macrovascular Events [PROactive]) have considered the impact of these PPAR agonists on cardiovascular disease, with mixed effects that require careful analysis, especially given ongoing trials and additional PPAR agonists in development.

Polyacrylamide gradient gel electrophoresis of lipoprotein subclasses

High-density (HDL), low-density (LDL), and very-low-density (VLDL) lipoproteins are heterogeneous cholesterol-containing particles that differ in their metabolism, environmental interactions, and association with disease. Several protocols use polyacrylamide gradient gel electrophoresis (GGE) to separate these major lipoproteins into known subclasses. This article provides a brief history of the discovery of lipoprotein heterogeneity and an overview of relevant lipoprotein metabolism, highlighting the importance of the subclasses in the context of their metabolic origins, fates, and clinical implications. Various techniques using polyacrylamide GGE to assess HDL and LDL heterogeneity are described, and how the genetic and environmental determinations of HDL and LDL affect lipoprotein size heterogeneity and the implications for cardiovascular disease are outlined.

Fenofibrate

Fenofibrate is a fibric acid derivative indicated for use in the treatment of primary hypercholesterolaemia, mixed dyslipidaemia and hypertriglyceridaemia in adults who have not responded to nonpharmacological measures. Its lipid-modifying effects are mediated by activation of peroxisome proliferator-activated receptor-alpha. Fenofibrate also has nonlipid (i.e. pleiotropic) effects (e.g. it reduces fibrinogen, C-reactive protein and uric acid levels and improves flow-mediated dilatation). Fenofibrate improves lipid levels (in particular triglyceride [TG] and high-density lipoprotein-cholesterol [HDL-C] levels) in patients with primary dyslipidaemia. Its lipid-lowering profile means that fenofibrate is particularly well suited for use in atherogenic dyslipidaemia (characterised by high TG levels, low HDL-C levels and small, dense low-density lipoprotein [LDL] particles), which is commonly seen in patients with the metabolic syndrome and type 2 diabetes mellitus. Indeed, fenofibrate improves the components of atherogenic dyslipidaemia in patients with these conditions, including a shift from small, dense LDL particles to larger, more buoyant LDL particles. Greater improvements in lipid levels are seen when fenofibrate is administered in combination with an HMG-CoA reductase inhibitor (statin) or in combination with ezetimibe, compared with monotherapy with these agents. In the DAIS study, fenofibrate significantly slowed the angiographic progression of focal coronary atherosclerosis in patients with type 2 diabetes. In terms of clinical outcomes, although no significant reduction in the risk of coronary events was seen with fenofibrate in the FIELD trial in patients with type 2 diabetes, treatment was associated with a significantly reduced risk of total cardiovascular disease (CVD) events, primarily through the prevention of non-fatal myocardial infarction and coronary revascularisation. Subgroup analyses revealed significant reductions in total CVD events and coronary heart disease events in patients with no previous CVD, suggesting a potential role for primary prevention with fenofibrate in patients with early type 2 diabetes. Improvements were also seen in microvascular outcomes with fenofibrate in the FIELD trial. Fenofibrate is generally well tolerated, both as monotherapy and when administered in combination with a statin. Combination therapy with fenofibrate plus a statin appears to be associated with a low risk of rhabdomyolysis; no cases of rhabdomyolysis were reported in patients receiving such therapy in the FIELD trial. Thus, fenofibrate is a valuable lipid-lowering agent, particularly in patients with atherogenic dyslipidaemia.

Clinical importance and therapeutic modulation of small dense low-density lipoprotein particles

The National Cholesterol Education Programme Adult Treatment Panel III accepted the predominance of small dense low-density lipoprotein (sdLDL) as an emerging cardiovascular disease (CVD) risk factor. Most studies suggest that measuring low-density lipoprotein (LDL) particle size, sdLDL cholesterol content and LDL particle number provides additional assessment of CVD risk. Therapeutic modulation of small LDL size, number and distribution may decrease CVD risk; however, no definitive causal relationship is established, probably due to the close association between sdLDL and triglycerides and other risk factors (e.g., high-density lipoprotein, insulin resistance and diabetes). This review addresses the formation and measurement of sdLDL, as well as the relationship between sdLDL particles and CVD. The effect of hypolipidaemic (statins, fibrates and ezetimibe) and hypoglycaemic (glitazones) agents on LDL size and distribution is also discussed.

Effects of fenofibrate on atherogenic dyslipidemia in hypertriglyceridemic subjects

BACKGROUND

The metabolic syndrome (MS) is often accompanied by atherogenic dyslipidemia, which is characterized by elevated triglycerides (TG), reduced high-density lipoprotein cholesterol (HDL-C), and elevated numbers of small, dense low-density lipoprotein (LDL) particles.

HYPOTHESIS

It was hypothesized that a threshold exists for the circulating TG level needed to produce changes in LDL subclass distribution.

METHODS

Hypertriglyceridemic (TG > or =300 and <1000 mg/dl) subjects with the MS were randomly assigned to placebo (n=50) or 130 mg/day of micronized fenofibrate-coated microgranules (n=96) for 8 weeks.

RESULTS

In the overall analysis, fenofibrate treatment resulted in significant (p < 0.05) changes versus placebo in TG (-36.6%), non-HDL-C (-7.5%), very low-density lipoprotein-C (-32.7%), LDL-C (15.0%), HDL-C (14.0%), remnant lipoprotein-C (-35.1%), apolipoprotein B (-6.0%), apolipoprotein A-I (5.3%), and apolipoprotein C-III--29.7%). Changes in LDL particle diameter in the fenofibrate group were significantly inversely associated with the TG level achieved on treatment (p = 0.019). When individually matched for percent change in TG, subjects with on-treatment TG < 200 mg/dl, in contrast to those with on-treatment values > or =200 mg/dl, had significantly different median responses (p < 0.05) in LDL size (0.79 vs. -0.06 nm) and cholesterol carried by small (-35 vs. 21 mg/dl) and large (31 vs. 11 mg/dl) particles.

CONCLUSION

These data support the view that a threshold exists below which the TG level must be lowered to produce shifts in LDL particle size.

Atorvastatin or fenofibrate on post-prandial lipaemia in type 2 diabetic patients with hyperlipidaemia

BACKGROUND

Post-prandial lipid abnormalities might contribute to the excess of cardiovascular risk typical of type 2 diabetic patients. The study evaluated the effects of atorvastatin (20 mg d(-1)) vs. fenofibrate (200 mg d(-1)) on post-prandial lipids in type 2 diabetic patients with mixed hyperlipidaemia.

MATERIALS AND METHOD

Eight type 2 diabetic patients, male/female (M/F) 6/2, age 58 +/- 5 years, body mass index (BMI) 28 +/- 3 kg m(-2) with cholesterol of low-density lipoprotein (LDL) between 100-160 mg dL(-1) and triglycerides between 150-400 mg dL(-1), participated in a randomized, cross-over study (3 months on atorvastatin and 3 months on fenofibrate). At baseline and at the end of the two treatments, the patients were given a standard fat meal; blood samples were taken before the meal and every 2 h after for the assay of cholesterol, triglycerides, apoB-48 and apoB-100 (determined by sodium dodecyl sulphate-polyacrylamide gel electrophoresis) in plasma lipoproteins and very low-density lipoprotein (VLDL) subfractions (large and small VLDL), separated by density gradient ultracentrifugation.

RESULTS

Data on fasting lipids confirmed that atorvastatin was more effective on the reduction of LDL-cholesterol, whereas fenofibrate was a better triglyceride-lowering agent. Concerning the post-prandial phase, the incremental areas under the curve (IAUC) for chylomicrons and large VLDL were reduced after both treatments, reaching statistical significance for cholesterol, triglyceride and apoB-100 content of chylomicrons only after fenofibrate administration [IAUC, (5.2 +/- 4.6 vs. 10.7 +/- 9.3) mg dL(-1) h(-1), P = 0.03; (131.3 +/- 95.1 vs. 259.1 +/- 201.5) mg dL(-1) h(-1), P = 0.02; (0.46 +/- 1 vs. 3 +/- 3.7) mg dL(-1) h(-1), P = 0.025, all respectively].

CONCLUSIONS

During the post-prandial state fenofibrate appeared to be more effective than atorvastatin in reducing the chylomicron response.

The Clinical Relevance of Low-Density-Lipoproteins Size Modulation by Statins

The predominance of small, dense low density lipoproteins (LDL) has been accepted as an emerging cardiovascular risk factor by the National Cholesterol Education Program Adult Treatment Panel III; in fact, LDL size seems to be an important predictor of cardiovascular events and progression of coronary heart disease. Several studies have also shown that the therapeutical modulation of LDL size is of great benefit in reducing the risk of cardiovascular events. Hypolipidemic treatment is able to alter LDL subclass distribution and statins are currently the most widely used lipid-lowering agents. Statins are potent inhibitors of hydroxy-methyl-glutaryl-coenzyme A reductase, the rate-limiting enzyme in hepatic cholesterol synthesis and are the main drugs of choice for the treatment of elevated plasma LDL cholesterol concentrations. Statins potentially lower all LDL subclasses (e.g., large, medium and small particles); thus, their net effect on LDL subclasses or size is often only moderate. However, a strong variation has been noticed among the different agents: analyses of all published studies suggest a very limited role of pravastatin and simvastatin in modifying LDL size and their subclasses, while fluvastatin and atorvastatin seem to be much more effective agents. Finally, rosuvastatin, the latest statin molecule introduced in the market, seems to be promising in altering LDL subclasses towards less atherogenic particles.

Thematic review series: patient-oriented research. What we have learned about VLDL and LDL metabolism from human kinetics studies

Lipoprotein metabolism is the result of a complex network of many individual components. Abnormal lipoprotein concentrations can result from changes in the production, conversion, or catabolism of lipoprotein particles. Studies in hypolipoproteinemia and hyperlipoproteinemia have elucidated the processes that control VLDL secretion as well as VLDL and LDL catabolism. Here, we review the current knowledge regarding apolipoprotein B (apoB) metabolism, focusing on selected clinically relevant conditions. In hypobetalipoproteinemia attributable to truncations in apoB, the rate of secretion is closely linked to the length of apoB. On the other hand, in patients with the metabolic syndrome, it appears that substrate, in the form of free fatty acids, coupled to the state of insulin resistance can induce hypersecretion of VLDL-apoB. Studies in patients with familial hypercholesterolemia, familial defective apoB, and mutant forms of proprotein convertase subtilisin/kexin type 9 show that mutations in the LDL receptor, the ligand for the receptor, or an intracellular chaperone for the receptor are the most important determinants in regulating LDL catabolism. This review also demonstrates the variance of results within similar, or even the same, phenotypic conditions. This underscores the sensitivity of metabolic studies to methodological aspects and thus the importance of the inclusion of adequate controls in studies.

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.

Low-density lipoprotein size and cardiovascular risk assessment

A predominance of small, dense low-density lipoproteins (LDL) has been accepted as an emerging cardiovascular risk factor by the National Cholesterol Education Program Adult Treatment Panel III. LDL size seems to be an important predictor of cardiovascular events and progression of coronary heart disease and evidences suggests that both quality (particularly small, dense LDL) and quantity may increase cardiovascular risk. However, other authors have suggested that LDL size measurement does not add information beyond that obtained by measuring LDL concentration, triglyceride levels and HDL concentrations. Therefore, it remains debatable whether to measure LDL particle size in cardiovascular risk assessment and, if so, in which categories of patient. Therapeutic modulation of LDL particle size or number appears beneficial in reducing the risk of cardiovascular events, but no clear causal relationship has been shown, because of confounding factors, including lipid and non-lipid variables. Studies are needed to investigate the clinical significance of LDL size measurements in patients with coronary and non-coronary forms of atherosclerosis; in particular, to test whether LDL size is associated with even higher vascular risk, and whether LDL size modification may contribute to secondary prevention in such patients.

Diabetes mellitus-associated atherosclerosis: mechanisms involved and potential for pharmacological invention

While diabetes mellitus is most often associated with hypertension, dyslipidemia, and obesity, these factors do not fully account for the increased burden of cardiovascular disease in patients with the disease. This strengthens the need for comprehensive studies investigating the underlying mechanisms mediating diabetic cardiovascular disease and, more specifically, diabetes-associated atherosclerosis. In addition to the recognized metabolic abnormalities associated with diabetes mellitus, upregulation of putative pathological pathways such as advanced glycation end products, the renin-angiotensin system, oxidative stress, and increased expression of growth factors and cytokines have been shown to play a causal role in atherosclerotic plaque formation and may explain the increased risk of macrovascular complications. This review discusses the methods used to assess the development of atherosclerosis in the clinic as well as addressing novel biomarkers of atherosclerosis, such as low-density lipoprotein receptor-1. Experimental models of diabetes-associated atherosclerosis are discussed, such as the streptozocin-induced diabetic apolipoprotein E knockout mouse. Results of major clinical trials with inhibitors of putative atherosclerotic pathways are presented. Other topics covered include the role of HMG-CoA reductase inhibitors and fibric acid derivatives with respect to their lipid-altering ability, as well as their emerging pleiotropic anti-atherogenic actions; the effect of inhibiting the renin-angiotensin system by either ACE inhibition or angiotensin II receptor antagonism; the effect of glycemic control and, in particular, the promising role of thiazolidinediones with respect to their direct anti-atherogenic actions; and newly emerging mediators of diabetes-associated atherosclerosis, such as advanced glycation end products, vascular endothelial growth factor and platelet-derived growth factor. Overall, this review aims to highlight the observation that various pathways, both independently and in concert, appear to contribute toward the pathology of diabetes-associated atherosclerosis. Furthermore, it reflects the need for combination therapy to combat this disease.

Gemfibrozil reduces small low-density lipoprotein more in normolipemic subjects classified as low-density lipoprotein pattern B compared with pattern A

We tested the hypothesis that gemfibrozil has a differential effect on low-density lipoprotein (LDL) and high-density lipoprotein (HDL) subclass distributions and postprandial lipemia that is different in subjects classified as having LDL subclass pattern A or LDL pattern B who do not have a classic lipid disorder. Forty-three normolipemic subjects were randomized to gemfibrozil (1,200 mg/day) or placebo for 12 weeks. Lipids and lipoproteins were determined by enzymatic methods. The mass concentrations of lipoproteins in plasma were determined by analytic ultracentrifugation and included the S(f) intervals: 20 to 400 (very LDL), 12 to 20 (intermediate-density lipoprotein), 0 to 12 (LDL), and HDL(2) mass (F(1.20) 3.5 to 9.0) and HDL(3) mass (F(1.20) 0 to 3.5). Postprandial measurements of triglycerides and lipoprotein(a) were taken after the patients consumed a 500 kcal/M(2) test meal. Treatment with gemfibrozil, compared with placebo, significantly reduced fasting plasma triglycerides (difference from placebo +/- SE; -50.2 +/- 20.6 mg/dl, p = 0.02), total cholesterol (-16.4 +/- 7.5 mg/dl, p = 0.04), apolipoprotein B (-16.1 +/- 5.5 mg/dl, p = 0.006), very LDL mass of S(f) 20 to 400 (-50.8 +/- 24.1 mg/dl, p = 0.02), S(f) 20 to 60 (-17.5 +/- 8.5 mg/dl, p = 0.05), S(f) 60 to 100 (-16.2 +/- 8.1 mg/dl, p = 0.05), and increased peak S(F) (0.48 +/- 0.27 Svedberg, p = 0.08). Gemfibrozil reduced the postprandial triglyceride level significantly at 3 (p = 0.04) and 4 (p = 0.05) hours after the test meal. A significantly different subclass response to gemfibrozil was observed in those with LDL pattern A versus B. Those with LDL pattern B had a significantly greater reduction in the small LDL mass S(f) 0 to 7 (p = 0.04), specifically regions S(f) 0 to 3 (p = 0.009) and S(f) 3 to 5 (p = 0.009). In conclusion, normolipemic subjects with either predominantly dense or buoyant LDL respond differently to gemfibrozil as determined by the changes in LDL subclass distribution. Thus, treatment with gemfibrozil may have additional antiatherogenic effects in those with LDL pattern B by decreasing small dense LDL that is not apparent in those with pattern A.

The beneficial effects of lipid-lowering drugs beyond lipid-lowering effects: a comparative study with pravastatin, atorvastatin, and fenofibrate in patients with type IIa and type IIb hyperlipidemia

Hyperlipidemia is an important risk factor for atherosclerosis. Hemorheological factors contribute to morbidity and mortality in patients with dyslipidemia. We evaluated the effects of 3 antihyperlipidemic drugs (pravastatin, atorvastatin, and fenofibrate), which have different mechanisms of action and different patterns of action on lipid profiles, on erythrocyte deformability and fibrinogen levels in patients with type IIa and type IIb hyperlipidemia. Twenty-one patients ( 4 men and 17 women) with type IIa and IIb hyperlipidemia were randomized to 3 drugs (pravastatin 20 mg/d, atorvastatin 10 mg/d, fenofibrate 250 mg/d) for 8 weeks. Plasma glucose, total cholesterol, triglyceride, high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) analysis were performed on a BM-Hitachi 747-200 autoanalyzer (Hitachi-Roche, Tokyo, Japan). Fibrinogen analysis was performed according to Clauss method. Erythrocyte deformability was assessed with cell transit analysis device. There was no significant difference in body mass index, lipid profile, fibrinogen level, and erythrocyte deformability index values among the groups before treatment ( P > .05). In all groups, there were statistically significant reductions in total LDL-C levels ( P < .05). The triglyceride levels were significantly reduced in the atorvastatin and fenofibrate groups ( P < .05), but not in the pravastatin group ( P > .05). There was no significant change in HDL-C levels during the treatment with statins ( P > .05), but there was a significant increase in the fenofibrate group ( P < .05). Mean erythrocyte deformability index was improved in all the groups ( P < .05). There was no significant change in fibrinogen levels during the treatment of pravastatin and atorvastatin ( P > .05), but in fenofibrate group, fibrinogen levels were significantly decreased ( P < .05). The 3 groups of antihyperlipidemic drugs have beneficial effects on the erythrocyte deformability index. Only fenofibrate has significant beneficial effects on the fibrinogen levels.

Effects of Atorvastatin on Low-Density Lipoprotein Cholesterol Phenotype and C-Reactive Protein Levels in Patients Undergoing Long-Term Dialysis

STUDY OBJECTIVES

To determine the effects of atorvastatin on low-density lipoprotein cholesterol (LDL) particle size and C-reactive protein (CRP) concentrations in patients undergoing long-term hemodialysis. Another objective was to compare the effects of atorvastatin on lipoprotein profiles as determined by direct versus indirect assessment of lipoprotein composition.

DESIGN

Randomized, parallel-group substudy.

SETTING

Two university-affiliated outpatient hemodialysis centers.

PATIENTS

Nineteen patients with LDL levels above 100 mg/dl and with at least two cardiovascular risk factors.

INTERVENTION

Patients were randomized in a 1:1 ratio to atorvastatin 10 mg/day or no treatment (control) for 20 weeks.

MEASUREMENTS AND MAIN RESULTS

We compared the differences between LDL particle size and CRP levels at baseline and 20 weeks in the atorvastatin versus control groups. Baseline demographic characteristics were similar between the two groups. Atorvastatin therapy was associated with no change in mean LDL particle size (p=0.23) and with a 90% decrease in mean CRP level (p=0.52). When evaluated by standard chemical analysis, atorvastatin therapy reduced total cholesterol levels by 29% (p=0.025) and resulted in nonsignificant reductions in LDL, high-density lipoprotein cholesterol, and triglyceride levels. Treatment with atorvastatin was not associated with significant changes in lipoprotein profile as determined by nuclear magnetic resonance (NMR) spectroscopy.

CONCLUSION

Treatment with atorvastatin did not affect LDL particle size but was associated with a sizable, yet nonsignificant, reduction in CRP concentrations. The drug had variable effects on lipoprotein concentrations as determined by chemical and NMR analytical methods. A larger study is necessary to provide definitive information on the effects of atorvastatin on LDL phenotype and CRP in patients with kidney disease.

Pharmacologic treatment of type 2 diabetic dyslipidemia

Patients with diabetes mellitus have a higher risk for cardiovascular heart disease (CHD) than does the general population, and once they develop CHD, mortality is higher. Good glycemic control will reduce CHD only modestly in patients with diabetes. Therefore, reduction in all cardiovascular risks such as dyslipidemia, hypertension, and smoking is warranted. The focus of this article is on therapy for dyslipidemia in patients with type 2 diabetes. Patients with the metabolic syndrome (insulin resistance) share similarities with patients with type 2 diabetes and may have a comparable cardiovascular risk profile. Diabetic patients tend to have higher triglyceride, lower high-density lipoprotein cholesterol (HDL), and similar low-density lipoprotein cholesterol (LDL) levels compared with those levels in nondiabetic patients. However, diabetic patients tend to have a higher concentration of small dense LDL particles, which are associated with higher CHD risk. Current recommendations are for an LDL goal of less than 100 mg/dl (an option of < 70 mg/dl in very high-risk patients), an HDL goal greater than 40 mg/dl for men and greater than 50 mg/dl for women, and a triglyceride goal less than 150 mg/dl. Nonpharmacologic interventions (diet and exercise) are first-line therapies and are used with pharmacologic therapy when necessary. Lowering LDL levels is the first priority in treating diabetic dyslipidemia. Statins are the first drug choice, followed by resins or ezetimibe, then fenofibrate or niacin. If a single agent is inadequate to achieve lipid goals, combinations of the preceding Drugs may be used. For elevated triglyceride levels, hyperglycemia must be controlled first. If triglyceride or HDL levels remain uncontrolled, pharmacologic agents should be considered. Fibrates are slightly more effective than niacin in lowering triglyceride levels, but niacin increases HDL levels appreciably more than do fibrates. Unlike gemfibrozil, niacin selectively increases subfraction Lp A-I, a cardioprotective HDL. Niacin is distinct in that it has a broad spectrum of beneficial effects on lipids and atherogenic lipoprotein subfraction levels. Niacin produces additive results when used in combination therapy. Recent data suggest that lower dosages and newer formulations of niacin can be used safely in diabetic patients with good glycemic control. Current evidence and guidelines mandate that diabetic dyslipidemia be treated aggressively, and lipid goals can be achieved in most patients with diabetes when all available products are considered and, if necessary, used in combination.

Effect of lipid-lowering drug therapy on small-dense low-density lipoprotein

OBJECTIVE

To review the effects of lipid-lowering therapy on small-dense low-density lipoprotein cholesterol (sdLDL-C).

DATA SOURCES

Literature was obtained from MEDLINE (1989-September 2004) and references of selected articles. Key search terms included small-dense LDL-C and lipid-lowering drug therapy.

DATA SYNTHESIS

Statins, fibrates, and niacin have demonstrated favorable effects on sdLDL-C, especially among patients with mixed dyslipidemia or hypertriglyceridemia. These effects include a reduction of sdLDL-C and/or a shift to the larger, less atherogenic LDL-C.

CONCLUSIONS

Data suggest that statins, fibrates, and niacin are effective at reducing concentrations of sdLDL-C and possibly normalizing LDL-C subclasses.

Atorvastatin

Atorvastatin (Lipitor) is an HMG-CoA reductase inhibitor with well documented lipid-lowering effects. It has recently been evaluated for the primary prevention of major cardiovascular events in patients with type 2 diabetes mellitus without elevated serum low-density lipoprotein (LDL)-cholesterol levels. Atorvastatin 10mg daily for 4 years was effective at reducing the risk of a first major cardiovascular event, including stroke, in a large, placebo-controlled, multicentre trial in patients with type 2 diabetes and at least one other coronary heart disease (CHD) risk factor, but without markedly elevated LDL-cholesterol levels. In this trial, known as CARDS (the Collaborative AtoRvastatin Diabetes Study), atorvastatin had a similar tolerability profile to that of placebo. Thus, atorvastatin has a potential role in the primary prevention of cardiovascular events in diabetic patients at risk of CHD, irrespective of pre-treatment LDL-cholesterol levels.

The effect of high dose atorvastatin therapy on lipids and lipoprotein subfractions in overweight patients with type 2 diabetes

Few data are available on the effects of high dose statin therapy on lipoprotein subfractions in type 2 diabetes. In a double blind randomised placebo-controlled trial we have studied the effects of 80 mg atorvastatin over 8 weeks on LDL, VLDL and HDL subfractions in 40 overweight type 2 diabetes patients. VLDL and LDL subfractions were prepared by density gradient ultracentrifugation. Triglycerides, cholesterol, total protein and phospholipids were measured and mass of subfractions calculated. HDL subfractions were prepared by precipitation. Atorvastatin 80 mg produced significant falls in LDL subfractions (LDL(1) 66.2 mg/dl:36.6 mg/dl, LDL(2) 118:56.6 mg/dl, LDL(3) 36.9:19.9 mg/dl all P < 0.01 relative to placebo) and VLDL subfractions (VLDL(1) 55:22.1 mg/dl, VLDL(2) 40.1:19.1 mg/dl, VLDL(3) 52.6:30 mg/dl all P < 0.01 relative to placebo). There was no change in the proportion of LDL present as LDL(3). There was a reduction in the proportion of VLDL as VLDL(1) and a reciprocal increase in the proportion as VLDL(3). Changes in VLDL subfractions were associated with changes in lipid composition, particularly a reduction in cholesterol ester and a reduction in the cholesterol ester/triglyceride ratio. Effects on HDL subfractions were largely neutral. High dose atorvastatin produces favourable effects on lipoprotein subfractions in type 2 diabetes which may enhance antiatherogenic potential.