Combination therapy in the management of mixed dyslipidaemia

Fenofibrate and Dyslipidemia: Still a Place in Therapy?

Dyslipidemia is one of the major cardiovascular risk factors, but beyond statin treatment-which represents the cornerstone of therapy-a relevant practical uncertainty regards the use of fibrate derivatives. In the lack of successful results from the main cardiovascular trials, guidelines recommend the use of peroxisome proliferator-activated receptor agonists in selected cases, i.e. patients with true atherogenic dyslipidemia. However, recent observations indicate that fenofibrate treatment may provide a reliable complementary support against residual cardiovascular risk. We therefore summarize current evidence on fenofibrate, seeking to provide an updated interpretation of recent studies in the field.

Cardiac autonomic neuropathy: Risk factors, diagnosis and treatment

Cardiac autonomic neuropathy (CAN) is a serious complication of diabetes mellitus (DM) that is strongly associated with approximately five-fold increased risk of cardiovascular mortality. CAN manifests in a spectrum of things, ranging from resting tachycardia and fixed heart rate (HR) to development of "silent" myocardial infarction. Clinical correlates or risk markers for CAN are age, DM duration, glycemic control, hypertension, and dyslipidemia (DLP), development of other microvascular complications. Established risk factors for CAN are poor glycemic control in type 1 DM and a combination of hypertension, DLP, obesity, and unsatisfactory glycemic control in type 2 DM. Symptomatic manifestations of CAN include sinus tachycardia, exercise intolerance, orthostatic hypotension (OH), abnormal blood pressure (BP) regulation, dizziness, presyncope and syncope, intraoperative cardiovascular instability, asymptomatic myocardial ischemia and infarction. Methods of CAN assessment in clinical practice include assessment of symptoms and signs, cardiovascular reflex tests based on HR and BP, short-term electrocardiography (ECG), QT interval prolongation, HR variability (24 h, classic 24 h Holter ECG), ambulatory BP monitoring, HR turbulence, baroreflex sensitivity, muscle sympathetic nerve activity, catecholamine assessment and cardiovascular sympathetic tests, heart sympathetic imaging. Although it is common complication, the significance of CAN has not been fully appreciated and there are no unified treatment algorithms for today. Treatment is based on early diagnosis, life style changes, optimization of glycemic control and management of cardiovascular risk factors. Pathogenetic treatment of CAN includes: Balanced diet and physical activity; optimization of glycemic control; treatment of DLP; antioxidants, first of all α-lipoic acid (ALA), aldose reductase inhibitors, acetyl-L-carnitine; vitamins, first of all fat-soluble vitamin B1; correction of vascular endothelial dysfunction; prevention and treatment of thrombosis; in severe cases-treatment of OH. The promising methods include prescription of prostacyclin analogues, thromboxane A2 blockers and drugs that contribute into strengthening and/or normalization of Na+, K+-ATPase (phosphodiesterase inhibitor), ALA, dihomo-γ-linolenic acid (DGLA), ω-3 polyunsaturated fatty acids (ω-3 PUFAs), and the simultaneous prescription of ALA, ω-3 PUFAs and DGLA, but the future investigations are needed. Development of OH is associated with severe or advanced CAN and prescription of nonpharmacological and pharmacological, in the foreground midodrine and fludrocortisone acetate, treatment methods are necessary.

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.

Diabetic cardiac autonomic neuropathy: Do we have any treatment perspectives?

Cardiac autonomic neuropathy (CAN) is a serious and common complication of diabetes mellitus (DM). Despite its relationship to an increased risk of cardiovascular mortality and its association with multiple symptoms and impairments, the significance of CAN has not been fully appreciated. CAN among DM patients is characterized review the latest evidence and own data regarding the treatment and the treatment perspectives for diabetic CAN. Lifestyle modification, intensive glycemic control might prevent development or progression of CAN. Pathogenetic treatment of CAN includes: balanced diet and physical activity; optimization of glycemic control; treatment of dyslipoproteinemia; correction of metabolic abnormalities in myocardium; prevention and treatment of thrombosis; use of aldose reductase inhibitors; dihomo-γ-linolenic acid (DGLA), acetyl-L-carnitine, antioxidants, first of all α-lipoic acid (α-LA), use of long-chain ω-3 and ω-6 polyunsaturated fatty acids (ω-3 and ω-6 PUFAs), vasodilators, fat-soluble vitamin B₁, aminoguanidine; substitutive therapy of growth factors, in severe cases-treatment of orthostatic hypotension. The promising methods include research and use of tools that increase blood flow through the vasa vasorum, including prostacyclin analogues, thromboxane A₂ blockers and drugs that contribute into strengthening and/or normalization of Na⁺, K⁺-ATPase (phosphodiesterase inhibitor), α-LA, DGLA, ω-3 PUFAs, and the simultaneous prescription of α-LA, ω-3 PUFA and DGLA.

Niacin extended release (ER)/simvastatin (Simcor®): a guide to its use in lipid regulation

Oral fixed-dose niacin extended release/simvastatin is associated with clinically relevant improvements in plasma lipid profiles, including lowering of non-high-density lipoprotein cholesterol levels, relative to simvastatin monotherapy in patients with mixed dyslipidemias who had not responded fully to simvastatin monotherapy, and is generally well tolerated.

Residual cardiovascular risk in secondary prevention

Despite substantial progress in the characterization and pharmacological treatment of risk factors associated with cardiovascular disease (CVD), residual cardiovascular risk represents a challenge to an effective CVD primary and secondary prevention. A multifactorial approach aimed at controlling all risk factors present in each individual patient is of paramount importance to effectively reduce the risk of CV events. While aggressive as compared to conventional LDL-cholesterol lowering provides further CV events reduction in secondary prevention patients, significant residual cardiovascular risk remains even after intensive statin therapy and an LDL-C levels of <70 mg/dL. Combination lipid-lowering strategies with a statin and fenofibrate or a statin and nicotinic acid may provide significant residual CV risk reduction in selected subgroups of patients (i.e. patients with diabetes on statin therapy and persistently low HDL-C and/or high triglycerides). Intensive risk factor management approaches aimed at controlling plasma LDL-C, glucose metabolism and blood pressure may significantly reduce residual CV risk; they should however be implemented based on individual cardiovascular risk profiles and clinical phenotypes, following the footsteps of personalized medicine.

Cardiovascular complications of diabetes: recent insights in pathophysiology and therapeutics

Cardiovascular complications represent the principal cause of death in patients with Type 2 diabetes. It is therefore of great importance to dissect the genetic determinants and molecular mechanisms responsible for diabetic cardiovascular complications. New research is of particular importance since, somewhat unexpectedly, large-scale clinical trials have indicated that glycemic control does not appear to have the anticipated major influence as a factor dictating cardiovascular outcome in diabetics. Hence, additional pathophysiological factors such as dyslipidemia, as well as proinflammatory and proatherosclerotic mechanisms, need to be more carefully examined. In this article, we will focus on recent studies in both animal models and humans as well as cellular mechanistic studies that advance our knowledge on the role of dyslipidemia, inflammation and atherosclerotic events in the cardiovascular complications of diabetes. We also translate our focus on research insights to related therapeutic opportunities.

Important considerations for treatment with dietary supplement versus prescription niacin products

Niacin is a water-soluble B vitamin (B3) known to have favorable effects on multiple lipid parameters, including raising high-density lipoprotein cholesterol (HDL-C) levels and lowering triglycerides (TGs), lipoprotein(a), and low-density lipoprotein cholesterol (LDL-C). Although LDL-C remains the primary target of lipid-altering therapy, current guidelines emphasize HDL-C and other modifiable lipid factors as key secondary targets. Thus, niacin is considered an important therapeutic option to help reduce the risk of cardiovascular disease in patients with mixed dyslipidemia who, in addition to high LDL-C, have elevated TGs and low HDL-C. Although available prescription niacin products, including immediate-release niacin (IR; Niacor) and an extended-release niacin formulation (Niaspan), have demonstrated safety and efficacy in randomized clinical trials, confusion remains among health care providers and their patients regarding the various commercially available nonprescription dietary supplement niacin products. These dietary supplements, which include IR, sustained-release (SR), and "no-flush" or "flush-free" niacin products, are not subject to the same stringent US Food and Drug Administration regulations as prescription drugs. In fact, both the American Heart Association and the American Pharmacists Association recommend against the use of dietary supplement niacin as a substitute for prescription niacin. Although some dietary supplement IR and SR niacin products have demonstrated a lipid response in clinical trials, products labeled as "no-flush" or "flush-free" that are intended to avoid the common niacin-associated adverse effect of flushing generally contain minimal or no free, pharmacologically active niacin and therefore lack beneficial lipid-modifying effects. To clarify important differences between available prescription and dietary supplement niacin products, this article contrasts current regulatory standards for dietary supplements and prescription drugs and provides an overview of available clinical data from key trials of niacin.

Statin or fibrate chronic treatment modifies the proteomic profile of rat skeletal muscle

Statins and fibrates can cause myopathy. To further understand the causes of the damage we performed a proteome analysis in fast-twitch skeletal muscle of rats chronically treated with different hypolipidemic drugs. The proteomic maps were obtained from extensor digitorum longus (EDL) muscles of rats treated for 2-months with 10mg/kg atorvastatin, 20 mg/kg fluvastatin, 60 mg/kg fenofibrate and control rats. The proteins differentially expressed were identified by mass spectrometry and further analyzed by immunoblot analysis. We found a significant modification in 40 out of 417 total spots analyzed in atorvastatin treated rats, 15 out of 436 total spots in fluvastatin treated rats and 21 out of 439 total spots in fenofibrate treated rats in comparison to controls. All treatments induced a general tendency to a down-regulation of protein expression; in particular, atorvastatin affected the protein pattern more extensively with respect to the other treatments. Energy production systems, both oxidative and glycolytic enzymes and creatine kinase, were down-regulated following atorvastatin administration, whereas fenofibrate determined mostly alterations in glycolytic enzymes and creatine kinase, oxidative enzymes being relatively spared. Additionally, all treatments resulted in some modifications of proteins involved in cellular defenses against oxidative stress, such as heat shock proteins, and of myofibrillar proteins. These results were confirmed by immunoblot analysis. In conclusions, the proteomic analysis showed that either statin or fibrate administration can modify the expression of proteins essential for skeletal muscle function suggesting potential mechanisms for statin myopathy.

Pharmacological effects of lipid-lowering drugs on circulating adipokines

The cardioprotective effects of lipid-lowering drugs have been primarily attributed to their effects on blood lipid metabolism. However, emerging evidence indicates that lipid-lowering drugs also modulate the synthesis and secretion of adipose tissue-secreted proteins referred to as adipokines. Adipokines influence energy homeostasis and metabolism and have also been shown to modulate the vascular inflammatory cascade. The purpose of this review will be to examine the reported effects of commonly used lipid-lowering drugs (statins, fibrates, niacin and omega-3-fatty acids) on the circulating concentrations of leptin, adiponectin, tumor necrosis-factor-α (TNF-α), Retinol binding protein 4 (RBP4) and resistin. Overall, the lipid-lowering drugs reviewed have minimal effects on leptin and resistin concentrations.Conversely, circulating adiponectin concentrations are consistently increased by each lipid-lowering drug reviewed with the greatest effects produced by niacin. Studies that have examined the effects of statins, niacin and omega-3-fatty acids on TNF-α demonstrate that these agents have little effect on circulating TNF-α concentrations. Niacin and fibrates appear to lower RBP4 but not resistin concentrations. The results of the available studies suggest that a strong relationship exists between pharmacological reductions in blood lipids and adiponectin that is not obvious for other adipokines reviewed.

A new paradigm for managing dyslipidemia with combination therapy: laropiprant + niacin + simvastatin

IMPORTANCE OF THE FIELD

Despite effective lowering of low-density lipoprotein cholesterol (LDL-C) with statin for prevention of cardiovascular adverse events, residual risk remains high due to low high-density lipoprotein cholesterol (HDL-C) levels in patients with mixed dyslipidemia. As a result, alternative treatment options to raise HDL-C are being investigated intensively. Currently, niacin is the most potent lipid lowering agent for raising HDL-C levels together with lowering of triglyceride and LDL-C. Previous clinical studies have demonstrated that niacin therapy significantly reduces the risk of cardiovascular events in high risk subjects. However, the clinical use of niacin is limited by its major adverse effect, cutaneous flushing. Although the use of extended-release (ER) formulation can reduce flushing, the tolerability and compliance of niacin remains suboptimal. A selective antagonist of prostaglandin D Type 1 receptor, laropiprant, has been investigated in a number of clinical studies and shown to be effective in reducing niacin-induced flushing. Despite the potential of laropiprant in reducing niacin-induced flushing, the long-term clinical efficacy and potential off-target side effects are not well studied. AREAS COVERED IN THIS REVIEWS: In this article, the pharmacological properties, clinical efficacy and future perspective of this combination therapy of simvastatin/ER niacin/laropiprant are reviewed.

WHAT THE READER WILL GAIN

Readers will understand both the mechanism and clinical effects of the combination therapy of simvastatin/ER niacin/laropiprant.

TAKE HOME MESSAGE

The triple combination therapy of simvastatin/ER niacin/laropiprant may reduce flushing side effects and facilitate a more comprehensive treatment for patients with mixed dyslipidemia.

Support of drug therapy using functional foods and dietary supplements: focus on statin therapy

Functional foods and dietary supplements might have a role in supporting drug therapy. These products may (1) have an additive effect to the effect that a drug has in reducing risk factors associated with certain conditions, (2) contribute to improve risk factors associated with the condition, other than the risk factor that the drug is dealing with, or (3) reduce drug-associated side effects, for example, by restoring depleted compounds or by reducing the necessary dose of the drug. Possible advantages compared with a multidrug therapy are lower drug costs, fewer side effects and increased adherence. In the present review we have focused on the support of statin therapy using functional foods or dietary supplements containing plant sterols and/or stanols, soluble dietary fibre, n-3 PUFA or coenzyme Q10. We conclude that there is substantial evidence that adding plant sterols and/or stanols to statin therapy further reduces total and LDL-cholesterol by roughly 6 and 10 %, respectively. Adding n-3 PUFA to statin therapy leads to a significant reduction in plasma TAG of at least 15 %. Data are insufficient and not conclusive to recommend the use of soluble fibre or coenzyme Q10 in patients on statin therapy and more randomised controlled trials towards these combinations are warranted. Aside from the possible beneficial effects from functional foods or dietary supplements on drug therapy, it is important to examine possible (negative) effects from the combination in the long term, for example, in post-marketing surveillance studies. Moreover, it is important to monitor whether the functional foods and dietary supplements are taken in the recommended amounts to induce significant effects.

Thinking beyond low-density lipoprotein cholesterol: strategies to further reduce cardiovascular risk

Several large statin trials and meta-analyses have demonstrated a reduction in low-density lipoprotein cholesterol (LDL-C) and cardiovascular morbidity and mortality. Some trials have also highlighted the significance of residual cardiovascular risk after treatment of LDL-C to target levels. This reflects the complex nature of residual cardiovascular risk. This residual risk is partially due to low HDL-C and high triglycerides (TG) despite achievement of LDL goals with statin therapy. The NCEP ATP III guidelines reported that low HDL-C is a significant and an independent risk factor for coronary heart disease (CHD) and is inversely related to CHD. Epidemiologic studies have also shown a similar inverse relationship of HDL-C with CHD. High-density lipoprotein cholesterol (HDL-C) may directly participate in the anti-atherogenic process by promoting efflux of cholesterol of the foam cells of atherogenic lesions. Many studies have demonstrated multiple anti-atherogenic actions of HDL-C and its role in promoting efflux of cholesterol from the foam cells. The residual risk by increased TG with or without low HDL-C can be assessed by calculating non-HDL-C and a reduction in TG results in decreased CHD.

Statins and fenofibrate affect skeletal muscle chloride conductance in rats by differently impairing ClC-1 channel regulation and expression

BACKGROUND AND PURPOSE

Statins and fibrates can produce mild to life-threatening skeletal muscle damage. Resting chloride channel conductance (gCl), carried by the ClC-1 channel, is reduced in muscles of rats chronically treated with fluvastatin, atorvastatin or fenofibrate, along with increased resting cytosolic calcium in statin-treated rats. A high gCl, controlled by the Ca(2+)-dependent protein kinase C (PKC), maintains sarcolemma electrical stability and its reduction alters muscle function. Here, we investigated how statins and fenofibrate impaired gCl.

EXPERIMENTAL APPROACH

In rats treated with fluvastatin, atorvastatin or fenofibrate, we examined the involvement of PKC in gCl reduction by the two intracellular microelectrodes technique and ClC-1 mRNA level by quantitative real time-polymerase chain reaction. Direct drug effects were tested by patch clamp analysis on human ClC-1 channels expressed in human embryonic kidney (HEK) 293 cells.

KEY RESULTS

Chelerythrine, a PKC inhibitor, applied in vitro on muscle dissected from atorvastatin-treated rats fully restored gCl, suggesting the involvement of this enzyme in statin action. Chelerythrine partially restored gCl in muscles from fluvastatin-treated rats but not in those from fenofibrate-treated rats, implying additional mechanisms for gCl impairment. Accordingly, a decrease of ClC-1 channel mRNA was found in both fluvastatin- and fenofibrate-treated rat muscles. Fenofibric acid, the in vivo metabolite of fenofibrate, but not fluvastatin, rapidly reduced chloride currents in HEK 293 cells.

CONCLUSIONS AND IMPLICATIONS

Our data suggest multiple mechanisms underlie the effect of statins and fenofibrate on ClC-1 channel conductance. While statins promote Ca(2+)-mediated PKC activation, fenofibrate directly inhibits ClC-1 channels and both fluvastatin and fenofibrate impair expression of mRNA for ClC-1.

Niacin extended-release/simvastatin

Niacin extended-release (ER)/simvastatin is a once-daily, fixed-dose combination of the HMG-CoA reductase inhibitor simvastatin and an ER formulation of niacin (a B-complex vitamin). In healthy volunteers who were given niacin ER/simvastatin 2000 mg/40 mg, niacin exposure was similar to that with niacin ER 2000 mg, while simvastatin exposure was increased compared to that with simvastatin 40 mg. In patients with elevated non-high-density lipoprotein cholesterol (non-HDL-C) but with low-density lipoprotein cholesterol (LDL-C) at or below the National Cholesterol Education Program (NCEP) goal after a > or = 2-week simvastatin 20 mg/day run-in period (SEACOAST I), 24 weeks of niacin ER/simvastatin 1000 mg/20 mg or 2000 mg/20 mg per day reduced median plasma non-HDL-C levels to a significantly greater extent than simvastatin 20 mg/day. In patients with elevated non-HDL-C and LDL-C at any level after a > or = 2-week simvastatin 40 mg/day run-in period (SEACOAST II), 24 weeks of niacin ER/simvastatin 1000 mg/40 mg or 2000 mg/40 mg per day was noninferior to simvastatin 80 mg/day in reducing median plasma non-HDL-C levels. Compared with simvastatin monotherapy, there was no significant difference in reduction in plasma LDL-C levels with niacin ER/simvastatin in SEACOAST I, and the noninferiority criterion for LDL-C was not met in SEACOAST II. However, plasma HDL-C levels increased more and triglyceride levels were lowered more than with simvastatin monotherapy (SEACOAST I and II). Niacin ER/simvastatin was generally well tolerated, with flushing being the most common adverse reaction.

Dyslipidemia in insulin resistance: clinical challenges and adipocentric therapeutic frontiers

The ever-increasing rates of obesity and diabetes worldwide have the potential to further fuel the epidemic of cardiovascular disease that we are experiencing today. To slow this epidemic successfully, insulin resistance and associated lipid abnormalities that frequently accompany it are key clinical targets. Yet, we are still challenged to reach the mandated clinical goals for lipids that would minimize the development and progression of cardiovascular disease. Adoption of a comprehensive approach by clinicians, in line with recent recommendations for stricter treatment goals for the at-risk patient, is essential to achieving cardiovascular risk reduction. The challenge for clinicians is integrating strategies, approaches and treatments that address the multiple metabolic defects in patients with insulin resistance and dyslipidemia. New perspectives can help effectively meet this ongoing challenge. Emerging evidence suggests that adipose tissue is intimately involved in the inter-relationships between insulin resistance and dyslipidemia. The future probably involves therapeutic strategies that directly target adipose tissue to optimally reduce cardiometabolic risk.