Abstract 15909: Response to Niacin Treatment in Men With Lipoprotein(a) Excess is Depended to Apolipoprotein(a) Isoforms
Background: Lipoprotein(a) [Lp(a)] is a cardiovascular risk factor that possesses a structural polymorphism connected with the repeats of kringle IV2 of apolipoprotein(a) [apo(a)]. As it was previously described apo(a) isoforms are divided into low- (LMW) and high-molecular weight (HMW) ones according to their electrophoretic mobility [G.Utermann et al, 1987]. There were no studies evaluated extended-release (ER) niacin effect on Lp(a) level depending on apo(a) phenotype.
Method: In this 24-week, prospective, open-label clinical trial we recruited 30 men (mean age 47±7 years) with Lp(a) level >20 mg/dL. All participants did not receive lipid-lowering therapy previously and started ER niacin 500 mg monotherapy with stepwise dose increasing up to 1.5-2.0 g as a goal. Subjects were evaluated for Lp(a), lipids, high-sensitivity C-reactive protein, lipoprotein-associated phospholipase A2, oxidized low-density lipoproteins, monocyte chemoattractant protein-1 and fibrinolytic markers (plasminogen activator inhibitor-1, tissue plasminogen activator/plasminogen activator inhibitor-1 complex, plasmin-antiplasmin complex).
Results: In accordance with apo(a) phenotype patients post hoc were divided into two equal groups by 15 subjects each. At baseline groups were comparable by age, lipids and other biomarkers levels. There was significant difference in baseline Lp(a) concentration: 74±30 mg/dl versus 38±26 mg/dl in LMW and HMW apo(a) groups, respectively, p=0.001. During the course of niacin treatment we obtained significant decreasing of levels of Lp(a) by 30%, lipoprotein-associated phospholipase A2 by 16%, plasminogen activator inhibitor type 1 by 20% in LMW apo(a) group (p<0.05 for all) whereas in HMW group these as well other non-lipid parameters remained unchanged.
Conclusions: High-dose ER niacin monotherapy declines elevated Lp(a) level in male subjects with low- but not high-molecular weight apo(a) isoforms. The reason for this remains unknown and deserves further evaluation.
- © 2013 by American Heart Association, Inc.