Genetics
Lp(a) assembles inside the cell from newly made LDL and apo(a), a stable-isotope kinetic study of 9 healthy people (Atherosclerosis 2012)
Original title: In vivo stable-isotope kinetic study suggests intracellular assembly of lipoprotein(a)
This study investigated Lp(a) assembly mechanisms using in vivo stable-isotope kinetics of apolipoprotein(a) [apo(a)] and apoB-100 from Lp(a) and LDL in 9 healthy volunteers, calculating fractional synthesis rate, production rate and retention time via multicompartmental modelling. Mean production rate was similar for apo(a) (1.15 nmol/kg/day) and apoB-100 from Lp(a) (1.31 nmol/kg/day), but significantly different from apoB-100 production from LDL (32.6 nmol/kg/day), with matching fractional synthesis rate and retention time patterns for Lp(a)-apo(a) and Lp(a)-apoB that differed from LDL-apoB. The findings suggest two distinct kinetic apoB pools within Lp(a) and LDL, consistent with intracellular assembly of Lp(a) from apo(a) and newly synthesised LDL.
Original abstract
Objective: Lipoprotein(a) [Lp(a)] consists of apolipoprotein B-100 (apoB-100) as part of an LDL-like particle and the covalently linked glycoprotein apolipoprotein(a) [apo(a)]. Detailed mechanisms of its biosynthesis, assembly, secretion and catabolism are still poorly understood. To address the Lp(a) assembly mechanism, we studied the in vivo kinetics of apo(a) and apoB-100 from Lp(a) and LDL apoB-100 in nine healthy probands using stable-isotope methodology.
Methods: The level of isotope enrichment was used to calculate the fractional synthesis rate (FSR), production rate (PR) and retention time (RT) using SAAMII software and multicompartmental modeling.
Results: We observed a similar mean PR for apo(a) (1.15 nmol/kg/d) and apoB-100 (1.31 nmol/kg/d) from Lp(a), which differed significantly from the PR for apoB-100 from LDL (32.6 nmol/kg/d). Accordingly, mean FSR and RT values for Lp(a)-apo(a) were similar to those of Lp(a)-apoB and different from those for LDL-apoB.
Conclusion: Two different kinetic apoB pools within Lp(a) and LDL suggest intracellular Lp(a) assembly from apo(a) and newly synthesized LDL.
Summary written by lp-a.org from the published abstract; figures as published. Page updated 18 August 2026. Methods.