title: Direct evidence in vivo of impaired macrophage-specific reverse cholesterol transport in ATP-binding cassette transporter A1-deficient mice.
abstract: The ATP-binding cassette transporter A1 (ABCA1) is a key regulator of high-density lipoprotein (HDL) metabolism. There is strong evidence that ABCA1 is a key regulator of reverse cholesterol transport (RCT). However, this could not be proved in vivo since hepatobiliary cholesterol transport was unchanged in ABCA1-deficient mice (ABCA1-/-). We used ABCA1-/- mice to test the hypothesis that ABCA1 is a critical determinant of macrophage-specific RCT. Although this cell-specific RCT only accounts for a tiny part of total RCT, it is widely accepted that it may have a major impact on atherosclerosis susceptibility. [(3)H]cholesterol-labeled endogenous macrophages were injected intraperitoneally into wild-type ABCA1+/+, ABCA1+/- and ABCA1-/- mice maintained on a chow diet. A direct relationship was observed between ABCA1 gene dose and plasma [(3)H]cholesterol at 24 and 48 h after the injection of tracer into the mice. Forty-eight hours after this injection, ABCA1-/- mice had significantly reduced [(3)H]cholesterol in liver (2.8-fold), small intestine enterocytes (1.7-fold) and feces (2-fold). To our knowledge, this is the first direct in vivo quantitative evidence that ABCA1 is a critical determinant of macrophage-specific RCT.
authors.affiliation: Servei de Bioquímica i Institut de Recerca, Hospital de la Santa Creu i Sant Pau, C/Antoni M. Claret 167, 08025 Barcelona, Spain.
authors.forename: Laura
authors.initials: L
authors.lastname: Calpe-Berdiel
authors.forename: Noemi
authors.initials: N
authors.lastname: Rotllan
authors.forename: Xavier
authors.initials: X
authors.lastname: Palomer
authors.forename: Vicent
authors.initials: V
authors.lastname: Ribas
authors.forename: Francisco
authors.initials: F
authors.lastname: Blanco-Vaca
authors.forename: Joan Carles
authors.initials: JC
authors.lastname: Escolà-Gil
mesh_terms: D064286:ATP Binding Cassette Transporter 1; D018528:ATP-Binding Cassette Transporters / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D001692:Biological Transport / Q000502:physiology; D002784:Cholesterol / Q000378:metabolism*; D008076:Cholesterol, HDL / Q000097:blood; D007421:Intestine, Small / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D008264:Macrophages / Q000378:metabolism*; D051379:Mice; D008817:Mice, Mutant Strains
chemical_list: D064286:ATP Binding Cassette Transporter 1; D018528:ATP-Binding Cassette Transporters; D008076:Cholesterol, HDL; D002784:Cholesterol