title: Ezetimibe enhances macrophage reverse cholesterol transport in hamsters: contribution of hepato-biliary pathway.
abstract: Reverse cholesterol transport (RCT) is pivotal in the return of excess cholesterol from peripheral tissues to the liver for excretion in bile and eventually feces. RCT from macrophages is a critical anti-atherogenicity mechanism of HDL. As the cholesterol absorption inhibitor ezetimibe promoted RCT in mice, which lack cholesterol ester transfer protein (CETP), we investigated its effects in hamsters, which have CETP. A high-cholesterol diet (HC) increased cholesterol levels throughout lipoprotein fractions and ezetimibe markedly reduced VLDL/LDL cholesterol levels under both normal chow (NC) and HC. However, ezetimibe did not affect and reduced HDL-cholesterol levels under NC and HC, respectively. Intraperitoneal injection of (3)H-cholesterol pre-labeled macrophages in an in vivo RCT assay increased tracer accumulation in the liver but reduced it in bile under HC, and these changes were completely cancelled by ezetimibe. Under both NC and HC, ezetimibe reduced tracer levels in the liver but increased them in feces, indicating promotion of RCT in vivo. We performed a RCT assay using hamsters subjected to bile duct ligation (BDL) to clarify whether a transintestinal cholesterol efflux (TICE) pathway contributes to ezetimibe's enhancement of RCT. BDL markedly inhibited macrophage-derived (3)H-cholesterol excretion to feces and cancelled ezetimibe's stimulatory effect on RCT, suggesting that biliary cholesterol excretion is a major contributor in RCT promotion by ezetimibe but the contribution of the TICE pathway is minimal. In conclusions, ezetimibe exerts an additive anti-atherogenic property by enhancing RCT in hamsters. Our findings suggest that this property is independent of the TICE pathway.
authors.affiliation: Division of Anti-aging and Vascular Medicine, Department of Internal Medicine, National Defense Medical College, Tokorozawa, Japan.
authors.forename: Harumi
authors.initials: H
authors.lastname: Uto-Kondo
authors.affiliation: Division of Anti-aging and Vascular Medicine, Department of Internal Medicine, National Defense Medical College, Tokorozawa, Japan. Electronic address: ayaori@ndmc.ac.jp.
authors.forename: Makoto
authors.initials: M
authors.lastname: Ayaori
authors.affiliation: Division of Anti-aging and Vascular Medicine, Department of Internal Medicine, National Defense Medical College, Tokorozawa, Japan.
authors.forename: Grace Megumi
authors.initials: GM
authors.lastname: Sotherden
authors.affiliation: Division of Anti-aging and Vascular Medicine, Department of Internal Medicine, National Defense Medical College, Tokorozawa, Japan.
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Nakaya
authors.affiliation: Division of Anti-aging and Vascular Medicine, Department of Internal Medicine, National Defense Medical College, Tokorozawa, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Sasaki
authors.affiliation: Division of Anti-aging and Vascular Medicine, Department of Internal Medicine, National Defense Medical College, Tokorozawa, Japan.
authors.forename: Makiko
authors.initials: M
authors.lastname: Yogo
authors.affiliation: Division of Anti-aging and Vascular Medicine, Department of Internal Medicine, National Defense Medical College, Tokorozawa, Japan.
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Komatsu
authors.affiliation: Division of Anti-aging and Vascular Medicine, Department of Internal Medicine, National Defense Medical College, Tokorozawa, Japan.
authors.forename: Shunichi
authors.initials: S
authors.lastname: Takiguchi
authors.affiliation: Division of Anti-aging and Vascular Medicine, Department of Internal Medicine, National Defense Medical College, Tokorozawa, Japan.
authors.forename: Emi
authors.initials: E
authors.lastname: Yakushiji
authors.affiliation: Division of Anti-aging and Vascular Medicine, Department of Internal Medicine, National Defense Medical College, Tokorozawa, Japan.
authors.forename: Masatsune
authors.initials: M
authors.lastname: Ogura
authors.affiliation: Division of Anti-aging and Vascular Medicine, Department of Internal Medicine, National Defense Medical College, Tokorozawa, Japan.
authors.forename: Takafumi
authors.initials: T
authors.lastname: Nishida
authors.affiliation: Division of Anti-aging and Vascular Medicine, Department of Internal Medicine, National Defense Medical College, Tokorozawa, Japan.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Endo
authors.affiliation: Division of Anti-aging and Vascular Medicine, Department of Internal Medicine, National Defense Medical College, Tokorozawa, Japan.
authors.forename: Katsunori
authors.initials: K
authors.lastname: Ikewaki
mesh_terms: D000818:Animals; D000924:Anticholesteremic Agents / Q000494:pharmacology*; D001384:Azetidines / Q000494:pharmacology*; D001646:Bile / Q000187:drug effects* / Q000378:metabolism; D001652:Bile Ducts / Q000601:surgery; D001692:Biological Transport / Q000187:drug effects; D053480:Cholesterol Ester Transfer Proteins / Q000378:metabolism; D008076:Cholesterol, HDL / Q000378:metabolism*; D008078:Cholesterol, LDL / Q000378:metabolism; D015243:Cholesterol, VLDL / Q000378:metabolism; D006224:Cricetinae; D004032:Diet; D000069438:Ezetimibe; D005243:Feces / Q000737:chemistry; D008099:Liver / Q000187:drug effects* / Q000378:metabolism; D008264:Macrophages / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D014316:Tritium
chemical_list: D000924:Anticholesteremic Agents; D001384:Azetidines; D053480:Cholesterol Ester Transfer Proteins; D008076:Cholesterol, HDL; D008078:Cholesterol, LDL; D015243:Cholesterol, VLDL; D014316:Tritium; D000069438:Ezetimibe
keywords: CETP; Ezetimibe; HDL; RCT; TICE