Short-term effects of niacin on plasma lipoproteins, HDL size and endothelial function in hipoalphalipoproteinemic individuals

Author(s)

Felipe Vendrame

• Document type: Master's Dissertation
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Faculdade de Ciências Médicas
• Defense date: 2014-02-28

Examining board members

Eliana Cotta de Faria; Eros Antonio de Almeida; Lázaro Alessandro Soares Nunes

• Advisor: Eliana Cotta de Faria; Andrei Carvalho Sposito

Abstract

Low plasma levels of high-density lipoprotein-cholesterol (HDL-C) are one of the risk factors involved in the development of atherosclerotic cardiovascular disease, the main cause of death in developed and emerging countries. Niacin is known as the main drug used to increase HDL-C levels. Reduced concentrations of high density lipoproteins are associated to oxidative stress vulnerability and tendency to endothelial dysfunction. Niacin, through the activation of its specific receptor coupled to G protein (GPR109A) promotes anti-inflammatory and antioxidant effects. Therefore, this study investigated the short-term effect of niacin and niacin associated to laropiprant on endothelial function, biochemical and physical-chemical serum parameters, in hypoalphalipoproteinemic subjects. The study was carried out in 18 asymptomatic subjects, male and female, aged between 20 and 60 years, with HDL-C plasma concentrations below 40 mg/dL. Subjects were treated with extended-release niacin 1g/day (NLE, Metri, Libbs Pharmaceutics, Sao Paulo, Brazil) and niacin associated to laropiprant 1g/20mg (NLE/LRPT, Cordaptive, Merck, Sao Paulo, Brazil), in a crossover study. The sequence of treatments was randomly determined. Plasma samples and flow-mediated dilatation of the brachial artery (FMD) were obtained in the beginning of the study, on the 7th day of treatment 1, on the 7th after washout and on the 7th day of treatment 2. After therapies with NLE and NLE/LRPT respectively, triglycerides (TG) concentrations decreased 4,0% and 3,0% (p <0,05) and HDL size 5,8% and 6,2%, (p <0,05); besides, glucose increased 5,0 and 8,0 % (p <0,02) and direct bilirubin 62% and 50% (p <0,04). The average increase of FMD was 4,5% and 4,1% on NLE and NLE/LRPT groups, respectively. No changes in HDL-C and the activity of cholesteryl ester transfer protein (CETP) after both treatments were observed. All these changes were reversed after the washout period. In intergroup analysis, no differences were found regarding variations in HDL-C, triglycerides, C reactive protein (CRP), direct bilirubin and FMD. These results suggest that short-term niacin therapy may improve endothelial function in subjects with low HDL-C concentrations. The addition of the PGD2 antagonist (laropiprant) did not influence niacin¿s effect on endothelial function (AU)

• FAPESP's process: 11/16544-4 - Short-term effects of niacin on plasma lipoproteins, HDL size and endothelial function in hipoalphalipoproteinemic individuals
• Grantee: Felipe Vendrame
• Support Opportunities: Scholarships in Brazil - Master