Effect of ezetimibe on the in vivo kinetics of apoB-48 and apoB-100 in men with primary hypercholesterolemia.
OBJECTIVE
To examine the impact of ezetimibe, a selective inhibitor of intestinal cholesterol absorption, on the in vivo kinetics of apolipoproteins (apo) B-48 and B-100 in humans.


RESULTS
Kinetics of triglyceride-rich lipoprotein (TRL) apoB-48 and very-low-density lipoprotein (VLDL), intermediate-density lipoprotein (IDL), and low-density lipoprotein (LDL) apoB-100 labeled with a stable isotope were assessed at baseline and at the end of 8 weeks of treatment with 10 mg/d of ezetimibe in 8 men with moderate primary hypercholesterolemia. Data were fit to a multicompartmental model using SAAMII to calculate fractional catabolic rate (FCR) and production rate (PR). Ezetimibe significantly decreased total and LDL cholesterol concentrations by -14.5% and -22.0% (P=0.004), respectively, with no significant change in plasma triglyceride and high-density lipoprotein (HDL) cholesterol levels. Ezetimibe had no significant effect on TRL apoB-48 kinetics and pool size (PS). However, VLDL and IDL apoB-100 FCRs were significantly increased (+31.2%, P=0.02 and +20.8%, P=0.04, respectively) with a concomitant elevation of VLDL apoB-100 PR (+20.9%, P=0.04). Furthermore, LDL apoB-100 PS was significantly reduced by -23.2% (P=0.004), caused by a significant increase in FCR of this lipoprotein fraction (+24.0%, P=0.04).


CONCLUSIONS
These results indicate that reduction of plasma LDL cholesterol concentration after treatment with ezetimibe is associated with an increase in FCR of apoB-100-containing lipoproteins.
Tremblay
André J
AJ
Lipid Research Center, CHUL Research Center, Québec, Canada.
Lamarche
Benoît
B
Cohn
Jeffrey S
JS
Hogue
Jean-Charles
JC
Couture
Patrick
P
D000328:Adult; D000924:Anticholesteremic Agents / Q000627:therapeutic use*; D053299:Apolipoprotein B-100; D053283:Apolipoprotein B-48; D001055:Apolipoproteins B / Q000378:metabolism*; D001384:Azetidines / Q000494:pharmacology / Q000627:therapeutic use*; D008078:Cholesterol, LDL / Q000097:blood; D000069438:Ezetimibe; D006801:Humans; D006937:Hypercholesterolemia / Q000188:drug therapy*; D008074:Lipoproteins / Q000378:metabolism; D053419:Lipoproteins, IDL; D008079:Lipoproteins, VLDL / Q000378:metabolism; D008297:Male; D008875:Middle Aged
D000924:Anticholesteremic Agents; D053299:Apolipoprotein B-100; D053283:Apolipoprotein B-48; D001055:Apolipoproteins B; D001384:Azetidines; D008078:Cholesterol, LDL; D008074:Lipoproteins; D053419:Lipoproteins, IDL; D008079:Lipoproteins, VLDL; D000069438:Ezetimibe