Laropiprant plus niacin for dyslipidemia and prevention of cardiovascular disease

Pharmacogenetics of cutaneous flushing response to niacin/laropiprant combination in Hong Kong Chinese patients with dyslipidemia

AIM

Cutaneous flushing with niacin varies between individuals and is substantially reduced by concomitant laropiprant. We investigated associations between baseline phenotypes and selected genotypes and flushing symptoms with niacin/laropiprant combination.

PATIENTS & METHODS

Flushing symptoms were quantified in 196 Chinese dyslipidaemic patients treated with niacin/laropiprant, and associations with phenotypes and selected polymorphisms were analyzed.

RESULTS

Moderate or severe flushing was associated with lower body mass index and the rs2279238 polymorphism in the LXRα on multivariate regression analysis and these factors accounted for 18.9% of the total variance.

CONCLUSION

Lower body mass index and the LXRα polymorphism appear to be associated with flushing symptoms with niacin/laropiprant. Whether these findings can be applicable to other niacin formulations without laropiprant needs to be verified.

High-Density Lipoprotein

High-density lipoprotein (HDL) is a complex mixture of lipoproteins that is associated with many minor proteins and lipids that influence the function of HDL. Although HDL is a promising marker and potential therapeutic target based on its epidemiological data and the effects of healthy HDL in vitro in endothelial cells and macrophages, as well as based on infusion studies of reconstituted HDL in patients with hypercholesterolemia, it remains still uncertain whether or not HDL cholesterol–raising drugs will improve outcomes. Recent studies suggest that HDL becomes modified in patients with coronary artery disease or acute coronary syndrome because of oxidative processes that result in alterations in its proteome composition (proteome remodelling) leading to HDL dysfunction.

Niacin administration significantly reduces oxidative stress in patients with hypercholesterolemia and low levels of high-density lipoprotein cholesterol

Oxidative stress has been implicated in the pathogenesis of cardiovascular disorders, including atherosclerosis. In pharmacological doses, niacin (vitamin B3) was proven to reduce total cholesterol, triglyceride, very-low-density lipoprotein, and low-density lipoprotein levels, and to increase high-density lipoprotein (HDL) levels. The aim of this study was to evaluate the effect of niacin treatment in patients with low levels of HDL cholesterol (HDL-C; <40 mg%) on their lipid profile and oxidative stress status. Seventeen patients with hypercholesterolemia and low HDL-C and 8 healthy control subjects were enrolled in the study. The patients were treated with niacin for 12 weeks. Lipid profile, oxidative stress and C-reactive protein (CRP) levels were determined at the time of enrollment, and 2 and 12 weeks after initiation of niacin treatment. Subjects with lower HDL-C levels exhibited higher oxidative stress compared with subjects with normal HDL-C levels. Niacin treatment in hypercholesterolemic patients caused a significant increase in HDL-C and apolipoprotein A1 levels, and a decrease in triglyceride levels. Niacin also significantly reduced oxidative stress, as measured by a significant decrease in the serum content of thiobarbituric acid reactive substances, lipid peroxides and paraoxonase activity, compared with the levels before treatment. Although serum CRP levels were not affected by niacin treatment, a correlation between CRP and HDL levels was obtained when computing the results. Niacin treatment in hypercholesterolemic patients with low HDL levels caused a significant decrease in their oxidative stress status. These results indicate an additional beneficial effect of niacin beyond its ability to affect the lipid profile.

Metabolic syndrome: nature, therapeutic solutions and options

INTRODUCTION

Metabolic syndrome (MetS) defines the clustering in an individual of multiple metabolic abnormalities, based on central obesity and insulin resistance. In addition to its five components, prothrombotic and proinflammatory states are essential features. The significance of MetS lies in its close association with the risk of type 2 diabetes and cardiovascular disease (CVD). This field being an evolving one necessitated the current review.

AREAS COVERED

The areas covered in this review include the so far unproven concept that enhanced low-grade inflammation often leads to dysfunction of the anti-inflammatory and atheroprotective properties of apolipoprotein A-I (apoA-I) and HDL particles, which further increases the risk of diabetes and CVD. It was emphasized that lifestyle modification is essential in the prevention and management of MetS, which includes maintenance of optimal weight by caloric restriction, adherence to a diet that minimizes postprandial glucose and triglyceride fluctuations, restricting alcohol consumption, smoking cessation and engaging in regular exercise. Drug therapy should target the dyslipoproteinemia and the often associated hypertension or dysglycemia.Statins are the drugs of first choice, to be initiated in patients with MetS at high 10-year cardiovascular risk. Such treatment is inadequate if fasting serum triglycerides remain at > 150 mg/dl, when niacin should be combined. Fibrates, omega 3 fatty acids, metformin, angiotensin-converting enzyme inhibitors and pioglitazone are additional options in drug therapy.

EXPERT OPINION

Research on MetS in subpopulations prone to impaired glucose tolerance and insulin resistance has indicated that proinflammatory state and oxidative stress are often prominently involved in MetS, to the extent that evidence of impaired function of HDL and apo A-I particles is discernible by biological evidence of functional defectiveness via outcomes studies and/or correlations with inflammatory and anti-inflammatory biomarkers. A sex difference has been clear in this development.

Extended release niacin-laropiprant in patients with hypercholesterolemia or mixed dyslipidemias improves clinical parameters

The progression of atherosclerosis remains a major cause of morbidity and mortality. Plaque formation is an immunological response driven by a number of risk factors, and reduction of risk is the primary goal of treatment. The role of LDL-C is well established and statins have proved effective drugs, although the relative risk reduction is only around 30%. The importance of other factors-notably low HDL-C and high TGs-has become increasingly clear and the search for alternative strategies continues. Niacin is particularly effective in achieving normalization of HDL-C but is clinically underutilized due to the side effect of cutaneous flushing. The discovery that flushing is mediated by mechanisms distinct from the lipid-lowering effects has led to the development of combination drugs with reduced side effects. This review considers the evidence regarding the clinical efficacy of extended-release niacin and the DP1 antagonist laropiprant in the treatment of hypercholesterolemia and mixed dyslipidemias.