Effects of comicronised fenofibrate on lipid and insulin sensitivity in patients with polymetabolic syndrome X

Impact of pemafibrate on lipid profile and insulin resistance in hypertriglyceridemic patients with coronary artery disease and metabolic syndrome

This study examined the effects of pemafibrate, a selective peroxisome proliferator-activated receptor α agonist, on the serum biochemical parameters of male patients with coronary artery disease and metabolic syndrome (MetS). This was a post hoc analysis of a randomized, crossover study that treated hypertriglyceridemia with pemafibrate or bezafibrate for 24 weeks, followed by a crossover of another 24 weeks. Of the 60 patients enrolled in the study, 55 were male. Forty-one of 55 male patients were found to have MetS. In this sub-analysis, male patients with MetS (MetS group, n = 41) and those without MetS (non-MetS group, n = 14) were compared. The primary endpoint was a change in fasting serum triglyceride (TG) levels during pemafibrate therapy, and the secondary endpoints were changes in insulin resistance-related markers and liver function parameters. Serum TG levels significantly decreased (MetS group, from 266.6 to 148.0 mg/dL, p < 0.001; non-MetS group, from 203.9 to 97.6 mg/dL, p < 0.001); however, a percent change (%Change) was not significantly different between the groups (- 44.1% vs. - 51.6%, p = 0.084). Serum insulin levels and homeostasis model assessment of insulin resistance significantly decreased in the MetS group but not in the non-MetS group. %Change in liver enzyme levels was markedly decreased in the MetS group compared with that in the non-MetS group (alanine aminotransferase, - 25.1% vs. - 11.3%, p = 0.027; gamma-glutamyl transferase, - 45.8% vs. - 36.2%, p = 0.020). In conclusion, pemafibrate can effectively decrease TG levels in patients with MetS, and it may be a more efficient drug for improving insulin resistance and liver function in such patients.

Current and emerging pharmacological therapy for non-alcoholic fatty liver disease

The main treatment of patients with non-alcoholic fatty liver disease (NAFLD) is life style modification including weight reduction and dietary regimen. Majority of patients are safely treated with this management and pharmacologic interventions are not recommended. However, a subgroup of NAFLD patients with non-alcoholic steatohepatitis (NASH) who cannot achieve goals of life style modification may need pharmacological therapy. One major obstacle is measurement of histological outcome by liver biopsy which is an invasive method and is not recommended routinely in these patients. Several medications, mainly targeting baseline mechanism of NAFLD, have been investigated in clinical trials for treatment of NASH with promising results. At present, only pioglitazone acting as insulin sensitizing agent and vitamin E as an anti-oxidant have been recommended for treatment of NASH by international guidelines. Lipid lowering agents including statins and fibrates, pentoxifylline, angiotensin receptor blockers, ursodeoxycholic acid, probiotics and synbiotics are current agents with beneficial effects for treatment of NASH but have not been approved yet. Several emerging medications are in development for treatment of NASH. Obeticholic acid, liraglutide, elafibranor, cenicriviroc and aramchol have been tested in clinical trials or are completing trials. Here in, current and upcoming medications with promising results in clinical trial for treatment of NAFLD were reviewed.

Renoprotective effect of a novel selective PPARα modulator K-877 in db/db mice: A role of diacylglycerol-protein kinase C-NAD(P)H oxidase pathway

OBJECTIVE

Several clinical studies have shown the beneficial effects of peroxisome proliferator-activated receptor α (PPARα) agonists on diabetic nephropathy. However, the molecular mechanism is not fully understood. Here we show that K-877, a novel selective PPARα modulator, ameliorates nephropathy in db/db mice via inhibition of renal lipid content and oxidative stress.

METHODS AND RESULTS

K-877 (0.5mg/kg/day) was administered to db/db mice for 2 or 12weeks. Short-term treatment did not affect body weight or plasma glucose levels in db/db mice, but attenuated albuminuria, along with improvement of plasma lipid profiles, lipid content including total diacylglycerol (DAG) levels, protein kinase C (PKC) activity, NAD(P)H oxidase-4 expression, and oxidative stress markers, all of which were significantly increased in diabetic kidneys. It increased phosphorylation of 5'-AMP activated protein kinase (AMPK) and acetyl-CoA carboxylase (ACC), and expression of several genes mediating fatty acid β-oxidation. In addition, long-term treatment ameliorated renal mesangial expansion in db/db mice and improved glycemic control.

CONCLUSIONS

K-877 administration ameliorates diabetic nephropathy, at least in part, via inhibition of renal lipid content and oxidative stress. The underlying mechanism may be mediated by modulating the renal AMPK-ACC pathway, subsequent acceleration of fatty acid β-oxidation and inhibition of fatty acid synthesis, and thus inhibition of the DAG-PKC-NAD(P)H oxidase pathway, in addition to its systemic effect including improvement of the plasma lipid profile and glycemic control.

In vitro bioassays to evaluate beneficial and adverse health effects of botanicals: promises and pitfalls

This review provides an update on the promises and pitfalls when using in vitro bioassays to evaluate beneficial and adverse health effects of botanicals and botanical preparations. Important issues addressed in the paper are: (i) the type of assays and biological effects available; (ii) false-positives, false-negatives and confounding factors; (iii) matrix and combination effects; (iv) extrapolation of in vitro data to the in vivo situation; (v) when (not) to use bioassays; and (vi) identification of active constituents. It is concluded that in vitro bioassays provide models to detect beneficial as well as adverse activities, but that linking these observations to individual ingredients and extrapolations to the in vivo situation is more complicated than generally anticipated.

Practical recommendations for the management of cardiovascular risk associated with atherogenic dyslipidemia, with special attention to residual risk. Spanish adaptation of a European Consensus of Experts

This document has discussed clinical approaches to managing cardiovascular risk in clinical practice, with special focus on residual cardiovascular risk associated with lipid abnormalities, especially atherogenic dyslipidaemia (AD). A simplified definition of AD was proposed to enhance understanding of this condition, its prevalence and its impact on cardiovascular risk. AD can be defined by high fasting triglyceride levels (≥2.3mmol/L / ≥200mg/dL) and low high-density lipoprotein cholesterol (HDL-c) levels (≤1,0 / 40 and ≤1,3mmol/L / 50mg/dL in men and women, respectively) in statin-treated patients at high cardiovascular risk. The use of a single marker for the diagnosis and treatment of AD, such as non-HDL-c, was advocated. Interventions including lifestyle optimization and low density lipoprotein (LDL) lowering therapy with statins (±ezetimibe) are recommended by experts. Treatment of residual AD can be performed with the addition of fenofibrate, since it can improve the complete lipoprotein profile and reduce the risk of cardiovascular events in patients with AD. Others clinical condictions in which fenofibrate may be prescribed include patients with very high TGs (≥5.6mmol/L / 500mg/dL), patients who are intolerant or resistant to statins, and patients with AD and at high cardiovascular risk. The fenofibrate-statin combination was considered by the experts to benefit from a favorable benefit-risk profile. In conclusion, cardiovascular experts adopt a multifaceted approach to the prevention of atherosclerotic cardiovascular disease, with lifestyle optimization, LDL-lowering therapy and treatment of AD with fenofibrate routinely used to help reduce a patient's overall cardiovascular risk.

Fenofibrate/simvastatin fixed-dose combination in the treatment of mixed dyslipidemia: safety, efficacy, and place in therapy

Lipids disorder is the principal cause of atherosclerosis and may present with several forms, according to blood lipoprotein prevalence. One of the most common forms is combined dyslipidemia, characterized by high levels of triglycerides and low level of high-density lipoprotein. Single lipid-lowering drugs may have very selective effect on lipoproteins; hence, the need to use multiple therapy against dyslipidemia. However, the risk of toxicity is a concerning issue. In this review, the effect and safety of an approved combination therapy with simvastatin plus fenofibrate are described, with an analysis of pros and cons resulting from randomized multicenter trials, meta-analyses, animal models, and case reports as well.

Metabolic Inflexibility with Obesity and the Effects of Fenofibrate on Skeletal Muscle Fatty Acid Oxidation

This study was designed to investigate mechanisms of lipid metabolic inflexibility in human obesity and the ability of fenofibrate (FENO) to increase skeletal muscle fatty acid oxidation (FAO) in primary human skeletal muscle cell cultures (HSkMC) exhibiting metabolic inflexibility. HSkMC from 10 lean and 10 obese, insulin resistant subjects were treated with excess fatty acid for 24 h (24hFA) to gauge lipid-related metabolic flexibility. Metabolically inflexible HSkMC from obese individuals were then treated with 24hFA in combination with FENO to determine effectiveness for increasing FAO. Mitochondrial enzyme activity and FAO were measured in skeletal muscle from subjects with prediabetes (n=11) before and after 10 weeks of fenofibrate in vivo. 24hFA increased FAO to a greater extent in HSkMC from lean versus obese subjects (+49% vs. +9%, for lean vs. obese, respectively; p<0.05) indicating metabolic inflexibility with obesity. Metabolic inflexibility was not observed for measures of cellular respiration in permeabilized cells using carbohydrate substrate. Fenofibrate co-incubation with 24hFA, increased FAO in a subset of HSkMC from metabolically inflexible, obese subjects (p<0.05), which was eliminated by PPARα antagonist. In vivo, fenofibrate treatment increased skeletal muscle FAO in a subset of subjects with prediabetes but did not affect gene transcription or mitochondrial enzyme activity. Lipid metabolic inflexibility observed in HSkMC from obese subjects is not due to differences in electron transport flux, but rather upstream decrements in lipid metabolism. Fenofibrate increases the capacity for FAO in human skeletal muscle cells, though its role in skeletal muscle metabolism in vivo remains unclear.

Effect of Fenofibrate on Serum Inflammatory Markers in Patients With High Triglyceride Values

Background: Atherosclerosis is the leading cause of death in developed countries. Although the mechanisms that underlie this process are not well defined, it has been proposed that atherosclerosis is mainly an inflammatory disease. In this context, a number of inflammatory markers have been studied for their ability to predict future cardiovascular events in asymptomatic individuals or patients with established atherosclerotic disease.

Methods and Results: The aim of our study was to evaluate the effect of micronized fenofibrate on serum inflammatory markers, such as C-reactive protein, fibrinogen, and plasma platelet-activating factor acetylhydrolase (PAF-AH) in patients with high triglyceride values. An analysis of baseline values revealed that hypertriglyceridemic patients (n = 58) exhibit an atherogenic phenotype, characterized not only by elevated lipid values but also by high concentrations of serum inflammatory markers. Along with the improvement in serum lipid profile (reduction in triglycerides and total cholesterol, low-density lipoprotein, and nonhigh-density lipoprotein-cholesterol, with a concomitant increase in high-density lipoprotein-cholesterol levels), fenofibrate administration significantly reduced the values of serum inflammatory markers by 34%, 9.5%, and 24.8% for C-reactive protein, fibrinogen, and plasma PAF-AH, respectively. However, with the exception of PAF-AH, these reductions in inflammatory markers were not correlated with the changes in lipid values.

Conclusions: In addition to its well-known hypolipidemic effects, fenofibrate may also possess significant anti-inflammatory properties that can contribute its antiatherogenic effect.

Effects of insulin and its related signaling pathways on lipid metabolism in the yellow catfish Pelteobagrus fulvidraco

The influence of insulin on hepatic metabolism in fish is not well understood. The present study was therefore conducted to investigate the effects of insulin on lipid metabolism, and the related signaling pathways, in the yellow catfish Pelteobagrus fulvidraco. Hepatic lipid and intracellular triglyceride (TG) content, the activity and expression levels of several enzymes and the mRNA expression of transcription factors (PPARα and PPARγ) involved in lipid metabolism were determined. Troglitazone, GW6471, fenofibrate and wortmannin were used to explore the signaling pathways by which insulin influences lipid metabolism. Insulin tended to increase hepatic lipid accumulation, the activity of lipogenic enzymes (6PGD, G6PD, ME, ICDH and FAS) and mRNA levels of FAS, G6PD, 6PGD, CPT IA and PPARγ, but down-regulated PPARα mRNA level. The insulin-induced effect could be stimulated by the specific PPARγ activator troglitazone or reversed by the PI3 kinase/Akt inhibitor wortmannin, demonstrating that signaling pathways of PPARγ and PI3 kinase/Akt were involved in the insulin-induced alteration of lipid metabolism. The specific PPARα pathway activator fenofibrate reduced insulin-induced TG accumulation, down-regulated the mRNA levels of FAS, G6PD and 6PGD, and up-regulated mRNA levels of CPT IA, PPARα and PPARγ. The specific PPARα pathway inhibitor GW6471 reduced insulin-induced changes in the expression of all the tested genes, indicating that PPARα mediated the insulin-induced changes of lipid metabolism. The present results contribute new knowledge on the regulatory role of insulin in hepatic metabolism in fish.

Lipid-lowering agents

The role of lipid lowering in reducing the risk of mortality and morbidity from cardiovascular disease (CVD) is well established. Treatment particularly aimed at decreasing low-density lipoprotein cholesterol (LDL-C) is effective in reducing the risk of death from coronary heart disease and stroke. Statins form the cornerstone of treatment. However, in some individuals with a high risk of CVD who are unable to achieve their target LDL-C due to either intolerance or lack of efficacy, there is the need for alternative therapies. This review provides an overview of the different classes of currently available lipid-lowering medications including statins, fibrates, bile acid sequestrants (resins), and omega-3 fatty acids. Data are presented on their indications, pharmacology, and the relevant end point clinical trial data with these drugs. It also discusses the human trial data on some novel therapeutic agents that are being developed including those for homozygous familial hypercholesterolemia--the antisense oligonucleotide mipomersen and the microsomal transfer protein inhibitor lomitapide. Data are presented on phase II and III trials on agents with potentially wider applications, cholesterol ester transfer protein inhibitors and proprotein convertase subtilisin kexin 9 inhibitors. The data on a licensed gene therapy for lipoprotein lipase deficiency are also presented.

The influence of fenofibrate on lipid profile, endothelial dysfunction, and inflammatory markers in type 2 diabetes mellitus patients with typical and mixed dyslipidemia

BACKGROUND

Type 2 diabetes is associated with early development of endothelial dysfunction. Patients present with typical dyslipidemia (predominantly high levels of triglycerides [TG] and low levels of high-density lipoprotein cholesterol [HDL-C]) or mixed hypercholesterolemia (high levels of low-density lipoprotein cholesterol [LDL-C] and TG with low HDL-C). Normal levels include LDL-C < 100 mg/dL, TG < 135 mg/dL, and HDL-C > 40 mg/dL for men and >50 mg/dL for women.

OBJECTIVE

To determine the effects of 8 weeks' administration of fenofibrate on inflammatory markers, metabolic parameters, and endothelial dysfunction.

METHODS

We administered micronized fenofibrate (Laboratories Fourneir S.A Dijon, France) daily for 8 weeks to 40 dyslipidemic, type 2 diabetes patients with equal numbers in each arm of the typical or mixed dyslipidemia groups. Noninvasive endothelial function assessments were performed and serum inflammatory markers obtained before and after treatment.

RESULTS

The typical group demonstrated significantly greater TG reduction and HDL-C increment, ie, 56% vs, 21.3% (P < .005) and 21% vs. 7.6% (P = .001), respectively, compared with the mixed group. There was greater LDL-C reduction within the mixed group compared with the typical group 21.0% vs. 2.2% (P < .05). Endothelial dysfunction was present in both groups at baseline. After treatment, the typical group demonstrated significant improvement in resting brachial diameter (3.9 mm [interquartile range {IQR} 3.3-4.7] to 4.2 mm [IQR 3.4-4.8], P = .001) compared with no change within the mixed group (3.6 mm [IQR 3.1-5.4] to 3.7 mm [IQR 3.1-5.3], P = .26). Flow-mediated diameter improved significantly in both groups. The mixed group had significantly greater levels of hs-CRP at baseline but no changes throughout the study. The mixed group demonstrated an increase in vascular adhesion molecule-1 from 706 ng/mL (IQR 566-1195) to 845 ng/mL (637-1653; P = .01), a reduction of tumor necrosis factor-α from 7.0 pg/mL (IQR 1.0-43.5) to 2.5 pg/mL (IQR 1.5-13.5; P = .04) throughout the study.

CONCLUSIONS

We effectively compared 8 weeks of fenofibrate therapy in type 2 diabetics with contrasting lipid abnormalities. The typical dyslipidemia group showed significantly greater lipid improvements compared with the mixed dyslipidemia group. Both groups had improvements in endothelial functions that were independent of the lipid levels. We concluded that fibrate therapy in type 2 diabetics is beneficial, especially those with typical dyslipidemia and extends beyond its lipid lowering properties.

Effect of bezafibrate on office, home and ambulatory blood pressure in hypertensive patients with dyslipidemia

It has been suggested that fibrates, lipid-lowering agents with a peroxisome proliferator-activated receptor-α agonistic property, lower blood pressure (BP) in some experimental models of hypertension. However, the effect of fibrates on BP in humans has been inconsistent, and there are few studies using home or ambulatory BP monitoring. We investigated the effects of bezafibrate on office, home and ambulatory BP in hypertensive patients with dyslipidemia. Thirty-two essential hypertensive patients with dyslipidemia (6 men and 26 women, mean age 65±8 years old) were assigned to a control period and a bezafibrate period (200 mg twice daily) for 8 weeks each in a randomized crossover manner. Bezafibrate significantly reduced serum triglyceride, total and low-density lipoprotein-cholesterol, blood glucose, plasma insulin, the homeostasis model assessment ratio and increased high-density lipoprotein-cholesterol. Compared with the control period, changes in office, home and 24-h BP with bezafibrate were -0.7±2.1/-1.6±1.2 mm Hg, +0.9±1.0/-0.5±0.6 and +0.8±1.4/-0.6±0.9 mm Hg, respectively. None of these differences in BP was significant. In conclusion, bezafibrate improved lipid metabolism and insulin sensitivity but did not affect office, home or ambulatory BP in hypertensive patients with dyslipidemia. Fibrates do not appear to lower BP in patients with essential hypertension.

Efficacy and safety of coadministration of fenofibrate and ezetimibe compared with each as monotherapy in patients with type IIb dyslipidemia and features of the metabolic syndrome: a prospective, randomized, double-blind, three-parallel arm, multicenter, comparative study

BACKGROUND

Patients with type IIb, or mixed, dyslipidemia have high levels of low-density lipoprotein cholesterol (LDL-C) with predominance of small dense LDL particles, high levels of triglycerides (TG), and low levels of high-density lipoprotein cholesterol (HDL-C). Fenofibrate significantly reduces TG and, more moderately, LDL-C, increases HDL-C and produces a shift from small to large LDL particle size; the main effect of ezetimibe is a reduction in LDL-C levels. Combined treatment with fenofibrate and ezetimibe may correct all the abnormalities of type IIb dyslipidemia.

OBJECTIVE

To assess the efficacy and safety of coadministration of fenofibrate (NanoCrystal(R)) and ezetimibe in patients with type IIb dyslipidemia and the metabolic syndrome compared with administration of fenofibrate and ezetimibe alone (ClinicalTrials.gov Identifier: NCT00349284; Study ID: CLF178P 04 01).

METHODS

This was a prospective, randomized, double-blind, three-parallel arm, multicenter, comparative study. Sixty ambulatory patients (mean age 56 years; 50% women, 50% men) were treated in each group. For inclusion in the study, patients were required to have LDL-C >or=4.13 mmol/L (>or=160 mg/dL), TG >or=1.71 mmol/L and <or=4.57 mmol/L (>or=150 mg/dL and <or=405 mg/dL), and at least two of the following National Cholesterol Education Program Adult Treatment Panel III criteria for the metabolic syndrome: low HDL-C or increased fasting plasma glucose, blood pressure, or waist circumference. Patients received fenofibrate 145 mg, ezetimibe 10 mg, or coadministration of both (fenofibrate/ezetimibe) daily for 12 weeks. The outcome measures were changes in lipids and related parameters, apolipoproteins, glucose metabolism parameters, and high-sensitivity C-reactive protein (hsCRP). Fenofibrate/ezetimibe was more effective than either fenofibrate or ezetimibe in reducing LDL-C (-36.2% vs -22.4% and -22.8%, respectively), non-HDL-C (-36.2% vs -24.8% and -20.9%, respectively), total cholesterol (TC) [-27.9% vs -18.9% and -17.1%, respectively], apolipoprotein B (-33.3% vs -24.5% and -18.7%, respectively), TC/HDL-C ratio (-34.2% vs -23.0% and -17.0%, respectively), and apolipoprotein B/apolipoprotein AI ratio (-37.5% vs -27.0% and -17.7%, respectively) [p < 0.001 for all comparisons between fenofibrate/ezetimibe and monotherapies].

RESULTS

Fenofibrate/ezetimibe was as effective as fenofibrate and more effective than ezetimibe in reducing remnant-like particle cholesterol (-36.2% and -30.7% vs -17.3%, respectively), and in increasing LDL size (+2.1% and +1.9% vs + 0.7%, respectively), apolipoprotein AI (+7.9% and +5.1% vs +0.2%, respectively) and apolipoprotein AII (+24.2% and +21.2% vs +2.7%, respectively). Fenofibrate/ezetimibe and fenofibrate were equally effective in reducing TG (both -38.3%) and in increasing HDL-C (+11.5% and + 7.9%, respectively; p = 0.282). Ezetimibe had minor effects on TG (-10.4%) and HDL-C (+2.2%). Among patients with low HDL-C at baseline (<1.29 mmol/L [<50 mg/dL] in women, <1.03 mmol/L [<40 mg/dL] in men), normalization of HDL-C was observed in 52.9% with fenofibrate/ezetimibe and in 58.8% with fenofibrate, compared with 20.0% with ezetimibe. Changes in hsCRP were -25.9% with fenofibrate/ezetimibe, -27.8% with fenofibrate, and -10.2% with ezetimibe (not statistically significant). None of the treatments altered glucose metabolism parameters.

CONCLUSION

In patients with type IIb dyslipidemia and features of the metabolic syndrome, coadministration of fenofibrate 145 mg and ezetimibe 10 mg daily was more effective than either monotherapy in reducing LDL-C, non-HDL-C, apolipoprotein B, and cardiovascular risk ratios, and was as effective as fenofibrate 145 mg alone in reducing TG and in increasing HDL-C in patients with low baseline HDL-C levels.

Fibrates: therapeutic potential for diabetic nephropathy?

Despite intensive glucose-lowering treatment and advanced therapies for cardiovascular risk factors, such as hypertension and dyslipidaemia, diabetes mellitus with its macro- and microvascular complications remains a major health problem. Especially diabetic nephropathy is a leading cause of morbidity and mortality, and its prevalence is increasing. Peroxisome proliferator-activated receptor-α (PPAR-α), a member of a large nuclear receptor superfamily, is expressed in several tissues including the kidney. Recently, experimental data have suggested that PPAR-α activation plays a pivotal role in the regulation of fatty acid oxidation, lipid metabolism, inflammatory and vascular responses, and might regulate various metabolic and intracellular signalling pathways that lead to diabetic microvascular complications. This review examines the role of PPAR-α activation in diabetic nephropathy and summarises data from experimental and clinical studies on the emerging therapeutic potential of fibrates in diabetic nephropathy.

Fenofibrate: a review of its use in dyslipidaemia

Fenofibrate is a fibric acid derivative indicated for the treatment of severe hypertriglyceridaemia and mixed dyslipidaemia in patients who have not responded to nonpharmacological therapies. The lipid-modifying effects of fenofibrate are mediated by the activation of peroxisome proliferator-activated receptor-α. Fenofibrate also has nonlipid, pleiotropic effects (e.g. reducing levels of fibrinogen, C-reactive protein and various pro-inflammatory markers, and improving flow-mediated dilatation) that may contribute to its clinical efficacy, particularly in terms of improving microvascular outcomes. Fenofibrate improves the lipid profile (particularly triglyceride [TG] and high-density lipoprotein-cholesterol [HDL-C] levels) in patients with dyslipidaemia. Compared with statin monotherapy, fenofibrate monotherapy tends to improve TG and HDL-C levels to a significantly greater extent, whereas statins improve low-density lipoprotein-cholesterol (LDL-C) and total cholesterol levels to a significantly greater extent. Fenofibrate is also associated with promoting a shift from small, dense, atherogenic LDL particles to larger, less dense LDL particles. Combination therapy with a statin plus fenofibrate generally improves the lipid profile to a greater extent than monotherapy with either agent in patients with dyslipidaemia and/or type 2 diabetes mellitus or the metabolic syndrome. In the pivotal FIELD and ACCORD trials in patients with type 2 diabetes, fenofibrate did not significantly reduce the risk of coronary heart disease events to a greater extent than placebo, and simvastatin plus fenofibrate did not significantly reduce the risk of major cardiovascular (CV) events to a greater extent than simvastatin plus placebo. However, the risk of some nonfatal macrovascular events and the incidence of certain microvascular outcomes were reduced significantly more with fenofibrate than with placebo in the FIELD trial, and in the ACCORD trial, patients receiving simvastatin plus fenofibrate were less likely to experience progression of diabetic retinopathy than those receiving simvastatin plus placebo. Subgroup analyses in the FIELD and ACCORD Lipid trials indicate that fenofibrate is of the greatest benefit in decreasing CV events in patients with atherogenic dyslipidaemia. Fenofibrate is generally well tolerated when administered alone or in combination with a statin. Thus, in patients with dyslipidaemia, particularly atherogenic dyslipidaemia, fenofibrate is a useful treatment option either alone or in combination with a statin.

Fenofibrate attenuates tubulointerstitial fibrosis and inflammation through suppression of nuclear factor-κB and transforming growth factor-β1/Smad3 in diabetic nephropathy

Fibrates, the ligands of peroxisome proliferator-activated receptor-alpha, have been shown to have a renal protective action in diabetic models of renal disease, but the mechanisms underlying this effect are unknown. In the present study, we sought to investigate in greater detail the effect of fenofibrate and its mechanism of action on renal inflammation and tubulointerstitial fibrosis in an animal model of type 2 diabetes mellitus. Twelve-week-old non-diabetic Zucker lean (ZL) and Zucker diabetic fatty (ZD) rats were treated with vehicle or fenofibrate for 10 weeks. mRNA and protein analyses were performed by real-time polymerase chain reaction, Western blot and immunostaining. The diabetic condition of ZD rats was associated with an increase in collagen and alpha-smooth muscle actin accumulation in the kidney, which was significantly reduced by fenofibrate. Chronic treatment of ZD rats with fenofibrate attenuated renal inflammation and tubular injury as evidenced by a decrease in mRNA and protein expression of secreted phosphoprotein-1, monocyte chemotactic protein-1 and kidney injury molecule-1 in the kidneys. Renal interstitial macrophage infiltration was also significantly reduced in the kidneys of fenofibrate-treated diabetic animals. Moreover, renal nuclear factor (NF)-kappaB DNA-binding activity, transforming growth factor (TGF)-beta1 and phospho-Smad3 proteins were significantly higher in ZD animals compared with ZL ones. This increase in NF-kappaB activity, TGF-beta1 expression and Smad3 phosphorylation was greatly attenuated by fenofibrate in the diabetic kidneys. Taken together, fenofibrate suppressed NF-kappaB and TGF-beta1/Smad3 signaling pathways and reduced renal inflammation and tubulointerstitial fibrosis in diabetic ZD animals.

Antiatherosclerotic and anti-insulin resistance effects of adiponectin: basic and clinical studies

Adiponectin is a protein secreted by adipose cells that may couple regulation of insulin sensitivity with energy metabolism and serve to link obesity with insulin resistance. Obesity-related disorders characterized by insulin resistance including the metabolic syndrome, diabetes, atherosclerosis, hypertension, and coronary artery disease are associated with both decreased adiponectin levels and endothelial dysfunction. Recent studies demonstrate that adiponectin has insulin-sensitizing effects as well as antiatherogenic properties. Lifestyle modifications and some drug therapies to treat atherosclerosis, hypertension, diabetes, and coronary heart disease have important effects in increasing adiponectin levels, decreasing insulin resistance, and improving endothelial dysfunction. In this review, we discuss insights into the relationships between adiponectin levels, insulin resistance, and endothelial dysfunction that are derived from various therapeutic interventions. The effects of lifestyle modifications and cardiovascular drugs on adiponectin levels and insulin resistance suggest plausible mechanisms that may be important for understanding and treating atherosclerosis and coronary heart disease.

Fenofibrate for cardiovascular disease prevention in metabolic syndrome and type 2 diabetes mellitus

Clinical guidelines highlight the importance of managing atherogenic mixed dyslipidemia to reduce the risk of premature cardiovascular disease in type 2 diabetes mellitus and metabolic syndrome. The lipid-modifying activity of fenofibrate, as demonstrated in clinical studies, indicates its effectiveness in treating dyslipidemia characteristic of these conditions. Fenofibrate also has a favorable impact on a number of nonlipid residual risk factors associated with type 2 diabetes and metabolic syndrome, mediated by peroxisome proliferator-activated receptor-alpha. In patients with type 2 diabetes, fenofibrate is effective in reducing the progression of coronary artery disease, as demonstrated by the Diabetes Atherosclerosis Intervention Study (DAIS). In the Fenofibrate Intervention and Event Lowering in Diabetes (FIELD) study, the primary end point (major coronary events) was not significantly reduced by fenofibrate treatment. However, other findings from this study suggest that fenofibrate reduces cardiovascular risk. Both DAIS and the FIELD study also indicate that fenofibrate may offer additional vascular benefits, specifically affecting the progression of diabetes-related microvascular disease.

Treatment of hyperlipidaemia with fenofibrate and related fibrates

BACKGROUND

Fenofibrate is the most widely used fibrate. Its efficacy and tolerability in the treatment of hypertriglyceridaemia and combined hyperlipidaemia have been demonstrated in several clinical trials.

OBJECTIVE

To review the pharmacology, lipid-lowering and extra-lipid effects of fenofibrate and to preview ABT-335, an investigational new fenofibric acid molecule.

RESULTS

The effects of fenofibrate are mediated through the active metabolite fenofibric acid, and are described in detail in the paper. ABT-335 is a salt of fenofibric acid and, unlike fenofibrate, does not require first pass metabolism to the active moiety. ABT-335 is being developed for combination use with statins, and has recently completed three large Phase III randomised controlled trials in which the efficacy and safety of ABT-335 in combination with the three most commonly prescribed statins, atorvastatin, simvastatin and rosuvastatin, was evaluated in patients with mixed dyslipidaemia.

CONCLUSION

ABT-335 in combination with statins may provide a safe and efficacious treatment modality that enables achievement of several therapeutic goals in patients with mixed dyslipidaemia who have high cardiovascular risk.

A pilot trial of fenofibrate for the treatment of non-alcoholic fatty liver disease

BACKGROUND

Dyslipidaemia and insulin resistance are two important risk factors for non-alcoholic fatty liver disease. Both factors can improve with fenofibrate.

AIMS

To evaluate the effect of fenofibrate on the clinical, analytical and histological evolution of patients with non-alcoholic fatty liver disease.

SUBJECTS AND METHODS

Sixteen consecutive patients with biopsy-confirmed non-alcoholic fatty liver disease were treated with 200mg/day of fenofibrate for 48 weeks. A clinical and biochemical follow-up was done every 3 months. A new liver biopsy was performed in all patients at the end of therapy.

RESULTS

All patients completed 48 weeks of therapy with fenofibrate, without adverse events. At the end of the study, a significant decrease in triglyceride, glucose, alkaline phosphatase and gamma-glutamyl transpeptidase and an increase of apolipoprotein A1 levels were found. Insulin levels and insulin resistance showed a trend to decrease. Moreover, a reduction in the proportion of patients with abnormal aminotransferase levels (>45IU/L) was observed (alanine aminotransferase: 93.7% vs. 62.5%, p=0.02; aspartate aminotransferase: 50% vs. 18.7%, p=0.02). The body mass index did not show any significant change, but the proportion of patients with metabolic syndrome decreased significantly (43.7% vs. 18.7%, p=0.04). A control biopsy after treatment revealed a decrease in the grade of hepatocellular ballooning degeneration (p=0.03), but the grade of steatosis, lobular inflammation, fibrosis or non-alcoholic fatty liver disease activity score did not change significantly.

CONCLUSIONS

In patients with non-alcoholic fatty liver disease, treatment with fenofibrate is safe and improves metabolic syndrome, glucose and liver tests. However, its effects on liver histology are minimal.

Vascular and metabolic effects of treatment of combined hyperlipidemia: focus on statins and fibrates

Combined hyperlipidemia results from overproduction of hepatically synthesized apolipoprotein B in very low-density lipoproteins in association with reduced lipoprotein lipase activity. Thus, this condition is typically characterized by concurrent elevations in total cholesterol and triglycerides with decreased high-density lipoprotein cholesterol. High levels of apolipoprotein B-containing lipoproteins, most prominently carried by low-density lipoprotein (LDL) particles, are an important risk factor for coronary heart disease. Statin therapy is highly effective at lowering LDL cholesterol. Despite the benefits of statin treatment for lowering total and LDL cholesterol, many statin-treated patients still have initial or recurrent coronary heart disease events. In this regard, combined therapy with statins and fibrates is more effective in controlling atherogenic dyslipidemia in patients with combined hyperlipidemia than either drug alone. Furthermore, statins and fibrates activate PPARalpha in a synergistic manner providing a molecular rationale for combination treatment in coronary heart disease. Endothelial dysfunction associated with cardiovascular diseases may contribute to insulin resistance so that there may also be additional beneficial metabolic effects of combined statin/fibrates therapy. However, there has been little published evidence that combined therapy is synergistic or even better than monotherapy alone in clinical studies. Therefore, there is a great need to study the effects of combination therapy in patients. When statins are combined with gemfibrozil therapy, this is more likely to be accompanied by myopathy. However, this limitation is not observed when fenofibrate, bezafibrate, or ciprofibrate are used in combination therapy.

PPAR-alpha agonist fenofibrate induces renal CYP enzymes and reduces blood pressure and glomerular hypertrophy in Zucker diabetic fatty rats

We have previously shown that fenofibrate, a peroxisome proliferator-activated receptor-alpha activator, increases renal cytochrome P450 (CYP)-derived eicosanoids and improves endothelial function in pre-diabetic obese rats. The present study was designed to explore the efficacy of fenofibrate on blood pressure and renal injury in the advanced stage of type-2 diabetes. 26-week-old male Zucker diabetic fatty rats (ZDF) were fed fenofibrate (100 mg/kg/day) for 6 weeks. Chronic treatment with fenofibrate normalized systolic blood pressure and reduced glomerular size by 19% in diabetic rats. Western blot and fluorescent immunostaining revealed that the over-expression of collagen type IV and alpha-smooth muscle actin was significantly attenuated in the kidney of fenofibrate-treated ZDF (F-ZDF) rats. In addition, fenofibrate administration dramatically decreased the cyclin D1 protein level in the kidney of diabetic rats. In contrast, renal CYP2C23 and CYP4A proteins were significantly increased in F-ZDF rats. These fenofibrate effects were observed in the absence of significant changes in glucose, insulin or lipid levels. Taken together, our results demonstrate that fenofibrate may lower blood pressure and attenuate glomerular hypertrophy and collagen accumulation through the downregulation of cyclin D1 and upregulation of CYP monooxygenases in the late stage of type-2 diabetes.

Role of fat metabolism in burn trauma-induced skeletal muscle insulin resistance

OBJECTIVE

Review current evidence on the role of fat in post-trauma insulin resistance, in reference to new studies with peroxisome proliferating activating receptor-alpha agonists.

DESIGN

Review.

SETTING

University laboratory.

PATIENTS

Thirty pediatric burn trauma patients.

INTERVENTIONS

Fourteen days of peroxisome proliferating activating receptor-alpha agonist immediately following burn trauma.

MEASUREMENTS AND MAIN RESULTS

We measured glucose metabolism and fat metabolism via tracer methodology and intracellular measurements. Insulin-stimulated glucose uptake is impaired following burn trauma, as is intracellular insulin signaling, palmitate oxidation, and mitochondrial oxidative capacity. Furthermore, levels of intracellular lipids are increased. Two weeks of peroxisome proliferating activating receptor-alpha treatment significantly reverses these pathologic changes incurred from burn injury.

CONCLUSIONS

Severe burn injury seriously affects multiple aspects of glucose and fat metabolism within the muscle, which can adversely affect clinical outcomes. Treatment with a peroxisome proliferating activating receptor-alpha drug may be a potential new therapeutic option.

Normalization of metabolic syndrome using fenofibrate, metformin or their combination

AIM

The aim of this study was to evaluate whether and to what extent fenofibrate (F), metformin (M) or a combination of these drugs improve characteristics of the metabolic syndrome (MetS).

METHODS

MetS was defined as the presence of >/=3 National Cholesterol Education Programme criteria, including >/=2 biochemical abnormalities. Patients with MetS were randomized to receive one of seven treatments twice daily for three months: F 80 mg + M 850 mg, F 80 mg + M 500 mg, F 40 mg + M 850 mg, F 40 mg + M 500 mg, F 80 mg + placebo, M 850 mg + placebo or placebo. 'Normalized' was defined as not having MetS biochemical abnormalities at the 3-month treatment period. A total of 681 patients were analysed (mean age 56 years, 59% men, mean body mass index 31.6 and 33.3 in male and female patients respectively).

RESULTS

High dose combination therapy led to normalization of biochemical parameters in 17.4% of patients, whereas only 5.8% of patients during F (p = 0.009) and 5.0% during M monotherapy (p = 0.005) exhibited normal biochemical values. Accordingly, F 80 mg + M 850 mg twice daily was most effective for normalizing triglycerides (55.0%), high-density lipoprotein cholesterol (35.0%) and fasting glucose (39.4%). All the treatments were well tolerated, with comparable adverse-event rates between groups.

CONCLUSIONS

Treatment with fenofibrate and metformin in combination led to normalization of biochemical abnormalities associated with the MetS more effectively compared with either therapy alone, without additional adverse effects. These data imply that high-dose combination therapy may offer additional therapeutic benefit particularly in patients with MetS.

Plasma triglycerides are not related to tissue lipids and insulin sensitivity in elderly following PPAR-alpha agonist treatment

Increases in plasma lipids, tissue triglycerides and decreases in mitochondrial function have been linked to insulin resistance and aging. In animals, peroxisome proliferator-activated receptor-alpha (PPAR-alpha) agonists decrease plasma lipids, intramyocellular fat (IMCL) and liver fat (LFAT) and improve mitochondrial beta-oxidative function and insulin sensitivity, but the effects in elderly were not known. Insulin sensitivity was assessed with a 2-h oral glucose tolerance test, magnetic resonance spectroscopy was used to asses IMCL, LFAT and plasma lipids were measured before and after 6, 11 and 61 days of PPAR-alpha agonist (fenofibrate) administration in 19 elderly (age 70+/-1 years) volunteers. Volunteers were stratified into healthy (N=7) and insulin resistant (N=12) groups. The baseline insulin sensitivity index (8.1+/-1.2 vs. 3.8+/-0.5, healthy vs. insulin resistant; P<0.001) was significantly higher in the healthy group. Fenofibrate treatment induced significant reductions in plasma triglycerides (P<0.001) and total cholesterol (P<0.001) in both groups. Nonetheless, neither fasted free fatty acids, glucose, insulin, nor insulin sensitivity improved in either group (day 1 vs. day 61, 8.1+/-1.2 vs. 8.1+/-0.9, healthy; and 3.8+/-0.5 vs. 4.2+/-0.05, insulin resistant). Furthermore, there was no change in IMCL or LFAT. These results indicate that whereas fenofibrate significantly lowers plasma lipids it neither affects insulin sensitivity nor intracellular lipids in elderly.

Effects of peroxisome proliferator-activated receptor (PPAR)-alpha and PPAR-gamma agonists on glucose and lipid metabolism in patients with type 2 diabetes mellitus

AIMS/HYPOTHESIS

The aim of the study was to examine the effects of pioglitazone (PIO), a peroxisome proliferator-activated receptor (PPAR)-gamma agonist, and fenofibrate (FENO), a PPAR-alpha agonist, as monotherapy and in combination on glucose and lipid metabolism.

SUBJECTS AND METHODS

Fifteen type 2 diabetic patients received FENO (n = 8) or PIO (n = 7) for 3 months, followed by the addition of the other agent for 3 months in an open-label study. Subjects received a 4 h hyperinsulinaemic-euglycaemic clamp and a hepatic fat content measurement at 0, 3 and 6 months.

RESULTS

Following PIO, fasting plasma glucose (FPG) (p < 0.05) and HbA(1c) (p < 0.01) decreased, while plasma adiponectin (AD) (5.5 +/- 0.9 to 13.8 +/- 3.5 microg/ml [SEM], p < 0.03) and the rate of insulin-stimulated total-body glucose disposal (R (d)) (23.8 +/- 3.8 to 40.5 +/- 4.4 micromol kg(-1) min(-1), p < 0.005) increased. After FENO, FPG, HbA(1c), AD and R (d) did not change. PIO reduced fasting NEFA (784 +/- 53 to 546 +/- 43 micromol/l, p < 0.05), triacylglycerol (2.12 +/- 0.28 to 1.61 +/- 0.22 mmol/l, p < 0.05) and hepatic fat content (20.4 +/- 4.8 to 10.2 +/- 2.5%, p < 0.02). Following FENO, fasting NEFA and hepatic fat content did not change, while triacylglycerol decreased (2.20 +/- 0.14 to 1.59 +/- 0.13 mmol/l, p < 0.01). Addition of FENO to PIO had no effect on R (d), FPG, HbA(1c), NEFA, hepatic fat content or AD, but triacylglycerol decreased (1.61 +/- 0.22 to 1.00 +/- 0.15 mmol/l, p < 0.05). Addition of PIO to FENO increased R (d) (24.9 +/- 4.4 to 36.1 +/- 2.2 micromol kg(-1) min(-1), p < 0.005) and AD (4.1 +/- 0.8 to 13.1 +/- 2.5 microg/ml, p < 0.005) and reduced FPG (p < 0.05), HbA(1c) (p < 0.05), NEFA (p < 0.01), hepatic fat content (18.3 +/- 3.1 to 13.5 +/- 2.1%, p < 0.03) and triacylglycerol (1.59 +/- 0.13 to 0.96 +/- 0.9 mmol/l, p < 0.01). Muscle adenosine 5'-monophosphate-activated protein kinase (AMPK) activity did not change following FENO; following the addition of PIO, muscle AMPK activity increased significantly (phosphorylated AMPK:total AMPK ratio 1.2 +/- 0.2 to 2.2 +/- 0.3, p < 0.01).

CONCLUSIONS/INTERPRETATION

We conclude that PPAR-alpha therapy has no effect on NEFA or glucose metabolism and that addition of a PPAR-alpha agonist to a PPAR-gamma agent causes a further decrease in plasma triacylglycerol, but has no effect on NEFA or glucose metabolism.

Single nucleotide polymorphisms of the peroxisome proliferator-activated receptor-alpha gene (PPARA) influence the conversion from impaired glucose tolerance to type 2 diabetes: the STOP-NIDDM trial

Peroxisome proliferator-activated receptor (PPAR) alpha, a transcription factor of the nuclear receptor superfamily, regulates fatty acid oxidation. We evaluated the association of single nucleotide polymorphisms (SNPs) of the PPAR-alpha gene (PPARA) with the conversion from impaired glucose tolerance to type 2 diabetes in 767 subjects of the STOP-NIDDM trial in order to investigate the effect of acarbose in comparison with placebo on the prevention of diabetes. In the placebo group, the G (162V) allele of rs1800206 increased the risk for diabetes by 1.9-fold (95% CI 1.05-3.58) and was associated with elevated levels of plasma glucose and insulin. The effect of this allele on the risk of diabetes in the placebo group was enhanced by the simultaneous presence of the risk alleles of the PPAR-gamma2, PPAR-gamma coactivator 1alpha, and hepatic nuclear factor 4alpha genes (odds ratios 2.2, 2.5, and 3.4, respectively). In the acarbose group, subjects carrying the minor G allele of rs4253776 and the CC genotype of rs4253778 of PPARA had a 1.7- and 2.7-fold increased risk for diabetes. Our data indicate that SNPs of PPARA increase the risk of type 2 diabetes alone and in combination with the SNPs of other genes acting closely with PPAR-alpha.

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.

PPARα agonist fenofibrate improves diabetic nephropathy in db/db mice

Peroxisome proliferator-activated receptor alpha (PPARalpha) is a member of the ligand-activated nuclear receptor superfamily, and plays an important role in lipid metabolism and glucose homeostasis. The purpose of this study is to determine whether the activation of PPARalpha by fenofbrate would improve diabetes and its renal complications in type II diabetes mellitus. Male C57 BLKS db/db mice and db/m controls at 8 weeks of age were divided to receive either a regular diet chow (db/db, n=8; db/m, n=6) or a diet containing fenofibrate (db/db, n=8; db/m, n=7). Mice were followed for 8 weeks. Fenofibrate treatment dramatically reduced fasting blood glucose (P<0.001) and HbA1c levels (P<0.001), and was associated with decreased food intake (P<0.01) and slightly reduced body weight. Fenofibrate also ameliorated insulin resistance (P<0.001) and reduced plasma insulin levels (P<0.05) in db/db mice. Hypertrophy of pancreatic islets was decreased and insulin content markedly increased (P<0.05) in fenofibrate-treated diabetic animals. In addition, fenofibrate treatment significantly reduced urinary albumin excretion (P<0.001). This was accompanied by dramatically reduced glomerular hypertrophy and mesangial matrix expansion. Furthermore, the addition of fenofibrate to cultured mesangial cells, which possess functional active PPARalpha, decreased type I collagen production. Taken together, the PPARalpha agonist fenofibrate dramatically improves hyperglycemia, insulin resistance, albuminuria, and glomerular lesions in db/db mice. The activation of PPARalpha by fenofibrate in mesangial cells may partially contribute to its renal protection. Thus, fenofibrate may serve as a therapeutic agent for type II diabetes and diabetic nephropathy.

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.

Lipid therapy for cardiovascular disease with insulin resistance, diabetes, or the metabolic syndrome

Insulin resistance with the development of diabetes or metabolic syndrome is associated with characteristic lipid abnormalities and an increased likelihood of cardiovascular events. This review examines the rationale and clinical trial evidence for the benefit of lipid drug therapy in the presence of these related high-risk conditions. In particular, the results of the more recent statin trials are discussed and contrasted with evidence from trials with fibrates, which, although fewer in number, appear to show that this particular therapy has selective benefit for the overweight individual with diabetes or features of the metabolic syndrome.

Beneficial vascular and metabolic effects of peroxisome proliferator-activated receptor-alpha activators

Fibric acid is a synthetic ligand of the nuclear receptor peroxisome proliferator-activated receptor (PPAR)-alpha that is highly expressed in skeletal muscle and heart, where it promotes beta-oxidation of fatty acids to mediate hypolipidemic actions. PPAR-alpha regulates expression of key proteins involved in atherogenesis, vascular inflammation, plaque instability, and thrombosis. Thus, PPAR-alpha may exert direct antiatherogenic actions in the vascular wall. Endothelial dysfunction associated with the metabolic syndrome and other insulin-resistant states is characterized by impaired insulin-stimulated nitric oxide production from the endothelium and decreased blood flow to skeletal muscle. Thus, improvement in insulin sensitivity leads to improved endothelial function. This may be an additional mechanism whereby fibrates decrease the incidence of coronary heart disease. Adiponectin is a protein secreted specifically by adipose cells that may couple regulation of insulin sensitivity with energy metabolism and serve to link obesity with insulin resistance. In this review, we discuss the mechanisms underlying the vascular and metabolic effects of fibrates that may act synergistically to prevent or regress atherosclerosis and coronary heart disease.

Fenofibrate prevents Rosiglitazone-induced body weight gain in ob/ob mice

AIMS/HYPOTHESIS

Fibrates and thiazolidinediones are commonly used for the treatment of dyslipidemia and type 2 diabetes, respectively. The aim of this study was to investigate the effects on body weight as well as on glucose and lipid homeostasis of ligands for PPARalpha and PPARgamma, Fenofibrate and Rosiglitazone, alone or in association.

METHODS

Ob/ob mice were divided into four groups: control, and mice daily injected (intraperitoneally), either with 10 mg/kg Rosiglitazone, 100 mg/kg Fenofibrate or both molecules. Body weight and food intake were monitored daily. After 13 days of treatment, mice were killed, and blood samples were collected for posterior metabolite quantification. The liver and adipose tissues were dissected and weighed.

RESULTS

Body weight was significantly reduced or increased by Fenofibrate and Rosiglitazone, respectively. The effect of Rosiglitazone was prevented by coadministration of Fenofibrate. This was accompanied by a normalization of the daily food efficiency. Compared to those treated with Rosiglitazone, animals treated with Fenofibrate alone or in combination presented a decreased white adipose tissue mass. Fenofibrate or Rosiglitazone alone significantly reduced the levels of plasma lipid parameters. Surprisingly, Fenofibrate also decreased blood glucose levels in ob/ob mice, despite having no effect on insulin levels. By contrast, both glucose and insulin levels were decreased by Rosiglitazone treatment. Coadministration of both drugs improved all parameters as with Rosiglitazone. Fenofibrate restored almost normal hepatocyte morphology and significantly reduced the triglyceride content of the liver. This was accompanied by an increase in fatty acid oxidation in the liver in all groups receiving Fenofibrate.

CONCLUSION/INTERPRETATION

These biological effects suggest that combined therapy with a PPARalpha and a PPARgamma ligand is more effective in ameliorating, specifically, lipid homeostasis than in activating any of this receptor separately. Furthermore, Fenofibrate prevents one of the most undesirable effects of Rosiglitazone, namely increased adiposity and body weight gain.

Lower plasma triglycerides are associated with increased need for insulin requirement in poorly controlled Type 2 diabetic patients

AIMS

To identify factors associated with insulin requirement in Type 2 diabetic patients, and to examine the significance of a normal plasma triglyceride level.

METHODS

One hundred and three poorly controlled (HbA1c = 9.4 +/- 1.9%) Type 2 diabetic patients initially not treated with insulin were followed up for 5 years. Insulin was administered if HbA1c > 8% despite maximal oral anti-diabetic treatment and bodyweight control. Variables were compared between insulin requiring and non-insulin-treated patients using unpaired t-tests. The outcomes of initially normotriglyceridaemic (< 1.7 mmol/l) and hypertriglyceridaemic patients were compared using unpaired t-tests, and a survival analysis (Cox proportional hazards model).

RESULTS

Sixty-three patients were transferred to insulin. They were 5 years older (P = 0.004), with a 3-year longer duration of their diabetes (P = 0.03), a 1.2% higher HbA1c (P = 0.002), and 50% lower triglyceride levels (P = 0.02) than the others. The survival analysis showed that a long duration of diabetes, a high HbA1c, and a normal triglyceride level were associated with the need for insulin; the effect of normotriglyceridaemia was significant in the most poorly controlled (HbA1c > 9.5%) patients (relative risk: 2.35, 95% confidence interval: 1.16-5.52, P = 0.016). The 46 normotriglyceridaemic patients were leaner (P = 0.0004) and had lower C-peptide levels (P = 0.0008) than the others. Despite similar diabetes duration and HBA1c, more were transferred to insulin (normotriglyceridaemic: 71%, hypertriglyceridaemic: 52%, P = 0.03).

CONCLUSION

A normal triglyceride level is associated with a need for insulin in poorly controlled Type 2 diabetes.

The effect of fenofibrate on the levels of high sensitivity C-reactive protein in dyslipidaemic hypertensive patients

It is now well documented that hypertension is associated with a chronic low-grade inflammatory state. Levels of high-sensitivity C-reactive protein (hs-CRP), a marker of systemic inflammation and a mediator of atherothrombotic disease, have been shown to correlate with cardiovascular disease risk. Our objective was to evaluate the effect of fenofibrate on the levels of hs-CRP in dyslipidaemic hypertensive patients. We selected 30 dyslipidaemic hypertensive patients and 20 normolipidemic normotensive healthy subjects. Dyslipidaemic hypertensive patients were treated with fenofibrate 200 mg/day for 3 months. Serum hs-CRP and metabolic parameters were evaluated at baseline in both groups and after fenofibrate treatment in dyslipidaemic hypertensive patients. At baseline, significantly higher hs-CRP levels were found in dyslipidaemic hypertensive patients than normal subjects (0.48 +/- 0.3 vs. 0.15 +/- 0.1 mg/dl, p < 0.01). Total cholesterol, low-density lipoprotein cholesterol and triglyceride significantly decreased (p < 0.05, p < 0.05 and p < 0.01, respectively), and levels of high-density lipoprotein cholesterol significantly increased (p < 0.05) after treatment with fenofibrate in dyslipidaemic hypertensive group. Levels of hs-CRP significantly decreased after fenofibrate treatment from a mean of 0.48 +/- 0.3 mg/dl to vs. 0.16 +/- 0.2 mg/dl, p < 0.01). Our findings suggest that fenofibrate may be used as a first-line therapy for improving the plasma lipids profile as well as the chronic low-grade inflammatory state in dyslipidaemia and hypertension.

Discovery of a Novel Series of Peroxisome Proliferator-Activated Receptor α/γ Dual Agonists for the Treatment of Type 2 Diabetes and Dyslipidemia

A series of 2-aryloxy-2-methyl-propionic acid compounds and related analogues were designed, synthesized, and evaluated for their PPAR agonist activities. 2-[(5,7-Dipropyl-3-trifluoromethyl)-benzisoxazol-6-yloxy]-2-methylpropionic acid (4) was identified as a PPARalpha/gamma dual agonist with relative PPARalpha selectivity and demonstrated potent efficacy in lowering both glucose and lipids in animal models without causing body weight gain. The PPARalpha activity of 4 appeared to have played a significant role in lowering glucose levels in db/db mice.

New lipid-lowering agents

Lipid-lowering is established as a proven intervention to reduce atherosclerosis and its complications. This article summarises imminent developments in lipid-lowering therapy, including new statins and cholesterol absorption inhibitors currently undergoing investigation for licensing. It also discusses other therapeutic targets such as squalene synthase, microsomal transfer protein (MTP), acyl-cholesterol acyl transferase (ACAT), cholesterol ester transfer protein (CETP), peroxosimal proliferator activating receptors (PPARs) and lipoprotein (a) (LP(a)), for which compounds have been developed and have at least reached trials in animal models. Lipid-lowering drugs are likely to prove a fast-developing area for novel treatments, as possible synergies exist between new and established compounds for the treatment of atherosclerosis.

Lipid-lowering therapies in development

Lipid lowering is established as a proven intervention to reduce atherosclerosis and its complications. This article summarises novel developments in the lipid-altering therapies under development, including combination therapies, squalene synthase inhibitors, microsomal transfer protein inhibitors, acyl-cholesterol acyl transferase inhibitors, cholesterol ester transfer protein antagonists, peroxisome proliferator-activated receptor agonists, high-density lipoprotein-derived peptides and inflammation inhibitors, which have at least reached trials in animal models. Lipid-altering drugs are likely to to be a fast-developing area for novel treatments as possible synergies exist between new and established compounds for the treatment of atherosclerosis. New agents will have to show significant advantage in tolerability or efficacy over existing agents and have the potential to be used in combination therapy as is well established for bile acid sequestrants, nicotinic acid or fibrates and statins. Any new drugs will also have to be assessed in clinical end-point trials against current compounds with proven outcome benefits.

Clinical usage of hypolipidemic and antidiabetic drugs in the prevention and treatment of cancer

Factors predisposing hormone-dependent tissues to the development of tumors coincide, at least partly, with hormonal-metabolic promoters (like insulin resistance, glucose intolerance, visceral obesity, etc.) of other main non-communicable diseases. This important knowledge poses the question of whether the same approach which is applied for prevention/treatment of a metabolic syndrome and the associated endocrine disorders might also be used in preventive and therapeutic oncology. Whereas an answer to this question remains controversial and is based mainly on experimental evidence, there is accumulating clinical data suggesting a practical significance of such a strategy, even though it is not to be considered as directly cytostatic. Among the many drugs under discussion, three groups of medicines (statins, antidiabetic biguanides, and thiazolidinediones) are the most attractive. The concept of metabolic rehabilitation is proposed and used practically in an adjuvant setting for the correction of the above-mentioned endocrine-metabolic disorders commonly found in cancer patients. The current use and aim of this approach is to improve the survival of patients and limit cancer progression. Nonetheless, it also appears potentially useful as a neoadjuvant therapy as well as a prophylactic treatment earlier in life for specific groups of people with hormone-associated enhanced oncological risk. It seems possible that certain hypolipidemic and antidiabetic medicines with pleiotropic effects might be combined with traditional antisteroid prevention/therapeutic approaches in routine clinical situations as well as for overcoming resistance to standard cancer hormonal therapies including receptor-negative cases. Characteristic at the end of the 20th and at the beginning of the 21st century is an epidemic of diabetes and obesity, which might further increase the incidence of certain cancers. This makes it timely to apply hypolipidemic and antidiabetic drugs (in combination with reasonable dieting, increased physical fitness, and an in-depth knowledge of drug-gene interactions) as an approach warranting further study.

Fenofibrate lowers adiposity and corrects metabolic abnormalities, but only partially restores endothelial function in dietary obese rats

In humans, dietary-induced obesity markedly increases plasma lipid profile and impairs vascular function leading to increased incidence of cardiovascular events. We have recently reported that chronic withdrawal of obesity-inducing diet attenuates obesity and completely corrects endothelial function. The aim of this study was to investigate whether fenofibrate-induced decrease in adiposity would also correct vascular function in the presence of obesity-inducing diet. Wistar rats were fed with either standard laboratory chow (lean, n = 9) or given a highly palatable diet (diet-fed, n = 18) for 15 weeks. After 7 weeks, half of the diet-fed group was treated with fenofibrate (fenofibrate-treated, n = 9) for 8 weeks before being sacrificed. Untreated diet-fed (n = 9) rats had significantly higher body weight, total fat mass (by up to two-fold, p < 0.001 for both), and raised fasting plasma levels of insulin, leptin and triglycerides (up to 110%; p < 0.001), but not glucose or nonesterified fatty acids (NEFA) than both lean control and fenofibrate-treated groups. Resistance mesenteric arteries responses to KCl- and noradrenaline-induced vasoconstriction were similar in all three groups. However, compared with lean controls, endothelium-dependent vasorelaxation responses were shifted to the right in both untreated and fenofibrate-treated diet-fed groups. Fenofibrate treatment improved endothelium-dependent vasorelaxation at only high carbamycholine concentrations (10 microM). There were no differences in endothelium-independent vasorelaxation between the three groups. These results indicate that, in the presence of obesity-inducing diet, fenofibrate markedly reverses obesity and corrects insulin resistance and lipid profile, but it only has a limited beneficial effect on vascular function. Therefore, it seems that diet component rather than obesity per se plays a key role in the genesis of vascular abnormalities.

Lipid-altering agents: the future

Lipid-lowering is established as proven intervention to reduce atherosclerosis and its complications. This article summarises novel developments in the lipid-altering therapies under development. It also discusses other therapeutic targets, such as squalene synthase, microsomal transfer protein, acyl-cholesterol acyl transferase, cholesterol ester transfer protein, peroxosimal proliferator-activating receptors and lipoprotein (a), for which compounds have been developed and have at least reached trials in animal models. Lipid-altering drugs are likely to prove a fast-developing area for novel treatments, as possible synergies exist between new and established compounds for the treatment of atherosclerosis.

The effect of fenofibrate on the levels of high sensitivity C-reactive protein in dyslipidemic obese patients

It is now well documented that obesity is associated with a chronic low-grade inflammatory state. Levels of high-sensitivity C-reactive protein, a marker of systemic inflammation and a mediator of atherothrombotic disease, have been shown to correlate with cardiovascular disease risk. Our objective was to evaluate the effect of fenofibrate on the levels of high-sensitivity C-reactive protein in dyslipidemic obese patients. We selected 30 dyslipidemic obese patients (body mass index > or = 30 kg/m2) and 20 normolipidemic, nonobese healthy subjects. Dyslipidemic obese patients were treated with fenofibrate 200 mg/day for 3 months. Serum high-sensitivity C-reactive protein and metabolic parameters were evaluated at baseline in both groups and after fenofibrate treatment in dyslipidemic obese patients. At baseline, significantly higher high-sensitivity C-reactive protein levels were found in dyslipidemic obese patients than normal subjects (0.58+/-0.3 vs 0.14+/-0.1 mg/dL, P < 0.01). Total cholesterol, low-density lipoprotein cholesterol, and triglyceride decreased significantly (P < 0.05, P < 0.05, and P < 0.01, respectively), and levels of high-density lipoprotein cholesterol significantly increased (P < 0.05) after treatment with fenofibrate in the dyslipidemic obese group. Levels of high-sensitivity C-reactive protein decreased significantly (approximately 74.1%) after fenofibrate treatment from a mean of 0.58+/-0.3 mg/dL to 0.15+/-0.2 mg/dL, P < 0.01. Our findings suggest that fenofibrate may be used as a first-line therapy for improving the plasma lipids profile, as well as the chronic low-grade inflammatory state in dyslipidemia and obesity.

A peroxisome proliferator-activated receptor-alpha activator induces renal CYP2C23 activity and protects from angiotensin II-induced renal injury

Cytochrome P450 (CYP)-dependent arachidonic acid (AA) metabolites are involved in the regulation of renal vascular tone and salt excretion. The epoxygenation product 11,12-epoxyeicosatrienoic acid (EET) is anti-inflammatory and inhibits nuclear factor-kappa B activation. We tested the hypothesis that the peroxisome proliferator-activated receptor-alpha-activator fenofibrate (Feno) induces CYP isoforms, AA hydroxylation, and epoxygenation activity, and protects against inflammatory organ damage. Double-transgenic rats (dTGRs) overexpressing human renin and angiotensinogen genes were treated with Feno. Feno normalized blood pressure, albuminuria, reduced nuclear factor-kappa B activity, and renal leukocyte infiltration. Renal epoxygenase activity was lower in dTGRs compared to nontransgenic rats. Feno strongly induced renal CYP2C23 protein and AA-epoxygenase activity under pathological and nonpathological conditions. In both cases, CYP2C23 was the major isoform responsible for 11,12-EET formation. Moreover, we describe a novel CYP2C23-dependent pathway leading to hydroxy-EETs (HEETs), which may serve as endogenous peroxisome proliferator-activated receptor-alpha activators. The capacity to produce HEETs via CYP2C23-dependent epoxygenation of 20-HETE and CYP4A-dependent hydroxylation of EETs was reduced in dTGR kidneys and induced by Feno. These results demonstrate that Feno protects against angiotensin II-induced renal damage and acts as inducer of CYP2C23-mediated epoxygenase activities. We propose that CYP-dependent EET/HEET production may serve as an anti-inflammatory control mechanism.