Fractional turnover of apolipoprotein(a) and apolipoprotein B-100 within plasma lipoprotein(a) particles in statin-treated patients with elevated and normal Lp(a) concentration

Abstract

ContextLipoprotein(a) [Lp(a)] is a highly atherogenic lipoprotein characterized by apolipoprotein(a) [apo(a)] covalently bounded to apoB-100 (apoB). However, the metabolism of apo(a) and apoB within plasma Lp(a) particles in patients on statins remains unclear. MethodsThe kinetics of Lp(a)-apo(a) and Lp(a)-apoB were determined in 20 patients with elevated Lp(a) (≥0.8 g/L; n = 10) and normal Lp(a) (≤0.3 g/L; n = 10) using stable isotope techniques and compartmental modeling. Plasma apo(a) concentration was measured using liquid chromatography–mass spectrometry. All patients were on statin therapy and were studied in the fasting state. ResultsThe fractional catabolic rate (FCR) of Lp(a)-apo(a) was not significantly different from that of Lp(a)-apoB in statin-treated patients with elevated or normal Lp(a) (P > 0.05 in both). Lp(a)-apo(a) FCR was significantly correlated with Lp(a)-apoB in patients with elevated and normal Lp(a) concentrations (r = 0.970 and r = 0.979, respectively; all P < 0.001) with Lin's concordance test showing substantial agreement between the FCRs of Lp(a)-apo(a) and Lp(a)-apoB in patients with elevated and normal Lp(a) concentrations (rc = 0.978 and rc = 0.966, respectively). ConclusionOur data indicate that the apo(a) and apoB proteins within Lp(a) particles have similar FCR and are therefore tightly coupled as an Lp(a) holoparticle in statin-treated patients with elevated and normal Lp(a) concentrations.