Delineation of molecular changes in intrahepatic cholesterol metabolism resulting from diminished cholesterol absorption.
Level 5 - mechanism / opinion, no new human data
Non-human animal study (mouse model)
PubMed 15654122 · doi:10.1194/jlr.M400475-JLR200
What was done
Female LDL receptor-deficient (LDLR-/-) and wild-type (LDLR+/+) mice were treated with ezetimibe (0 to 10 mg/day/kg body weight) added to either a basal diet or a lipid-rich diet to examine changes in intrahepatic cholesterol metabolism, biliary lipid secretion, and plasma lipoprotein levels.
What was found
In LDLR-/- mice on a basal diet, ezetimibe reduced cholesterol absorption by up to 91%, increased fecal neutral sterol excretion by up to 4.7-fold, and decreased plasma total cholesterol by up to 18%. In LDLR-/- mice on a lipid-rich diet, ezetimibe prevented the accumulation of VLDL and LDL in the circulation. In LDLR+/+ mice on a lipid-rich diet, ezetimibe resulted in a 2-fold increase in hepatic LDLR mRNA expression compared to diet alone.
Why it matters
This study defines the mechanisms behind the lipid-lowering effects of ezetimibe in mice, demonstrating that reduced cholesterol absorption lowers circulating LDL-C through both decreased lipoprotein production and upregulated hepatic LDLR expression.
Limits
The study was conducted entirely in female mice, sample sizes were not reported in the abstract, and direct translation to human hepatic cholesterol dynamics cannot be assumed without clinical validation.
Cited by
- supports Ezetimibe upregulates hepatic LDL receptors by inhibiting intestinal cholesterol reabsorption transporters.