Journal of Lipid Research, Vol 34, 1975-1982, Copyright © 1993 by Lipid Research, Inc.
Lovastatin enhances hepatic uptake of low density lipoprotein in humans
K Kervinen, MJ Savolainen, JI Heikkila and YA Kesaniemi
Department of Internal Medicine, University of Oulu, Finland.
A noninvasive method for visualizing the uptake of low density lipoprotein
(LDL) was used to investigate the effect of hypolipidemic drugs on LDL
uptake by the human liver in vivo. Fourteen hypercholesterolemic patients
(six with familial hypercholesterolemia and eight with common
hypercholesterolemia) were studied. Autologous LDL particles were isolated
and divided into two aliquots; one was labeled with 99mTC and the other
with 131I, and both preparations were reinjected simultaneously. The
labeled LDL was visualized 24 h later by scanning the thorax and abdomen
with a gamma camera, and the liver/heart ratio was calculated as an
estimate of the hepatic uptake of LDL. The results of 99mTC-labeled LDL
scintigraphy were compared with conventional determinations of the
fractional catabolic rate (FCR) for 131I-labeled LDL. The latter correlated
best with the liver/heart ratio (r = 0.80, P < 0.001). Lovastatin
treatment increased the liver/heart ratio (15%, P < 0.01) in the
patients with polygenic hypercholesterolemia and the FCR for LDL in both
groups (22%, P < 0.05, for those with familial hypercholesterolemia and
37%, P < 0.01 for those with polygenic hypercholesterolemia). Scanning
of the liver using the 99mTC-labeled LDL method provides a noninvasive
method for visualizing the hepatic uptake of LDL in vivo in humans. This
study also provides direct proof that lovastatin, a drug that enhances LDL
receptor activity in the liver, also increases the hepatic uptake of LDL in
humans.