HDL-PARTICLES SEPARATION EMPLOYING DIFFERENT PRECIPITATING AGENTS: FUNCTIONAL PROPERTIES OF THE IMPACT OF CHEMICAL PRECIPITATION ON LIPOPROTEIN PARTICLE-SIZE AND PARAOXONASE-1-ACTIVITY

First-generation methods used to quantify HDL-cholesterol have been used for decades. Therefore, first-generation precipitatingreagents still in use, the chemical impact on HDL-particles functionality (structure/activity-relationship) is not well-documented. The study aim was to identify the most efficient precipitating-reagent for lipoprotein separation to be used in the HDL functionalevaluation. A cross-sectional design with convenience sampling was conducted. Plasma samples from 40 individuals, both genders, were evaluated. Biochemical analysis was performed after using different chemical precipitants (e.g. polyethylene glycol - PEG (P1), phosphotungstic-acid (P2), and dextran-sulfate/MgCl2 (P3)) to evaluate HDL-particle-size and PON1-activity. Parametric and non-parametric tests were performed using GraphPad-Prism 5.01 (USA). Differences were considered significant when a p-value < 0.05 were obtained. The PON1-activity comparison differed after NaCl stimulation (p < 0.001, paired t-test) and among chemical precipitant treatments. The PON1-activity differed after sample precipitation with P1 when compared to P2, and P3 (p < 0.05; ANOVA), before and after stratification for dyslipidemia group. The HDL particle-size comparison did not differ, but on the other hand, polydispersity differed after sample precipitation with P3 when compared to P1 or P2 (p < 0.05; ANOVA). Dextran- Sulfate/MgCl2 was a better chemical precipitant for PON1-activity, and PEG for HDL-particle-size, respectively. The HDL functional