title: Different effects of subclasses of HDL containing apoA-I but not apoA-II (LpA-I) on cholesterol esterification in plasma and net cholesterol efflux from foam cells.
abstract: We investigated the effects of subclasses of plasma LpA-I (HDL containing apoA-I but not apoA-II) on cholesterol esterification in plasma and net cholesterol efflux from foam cells. LpA-I was composed of particles of three diameters: large (11.1 nm; Lg-LpA-I), medium (8.8 nm; Md-LpA-I), and small (7.7 nm; Sm-LpA-I). Plasma concentrations of LpA-I were positively correlated only with the level of Lg-LpA-I. Plasma concentrations of Lg-LpA-I were inversely correlated with the rate of cholesterol esterification in plasma and VLDL- and LDL-depleted plasma. Plasma concentrations of Md-LpA-I and Sm-LpA-I did not correlate with the rate of cholesterol esterification in plasma or VLDL- and LDL-depleted plasma. When macrophage foam cells were incubated with Md- and Sm-LpA-I, cellular cholesterol mass was reduced by approximately 70%. In contrast, the cellular cholesterol-reducing capacity of Lg-LpA-I was negligible. Lg-LpA-I inhibited net cholesterol removal from foam cells that was mediated by Md- and Sm-LpA-I and cholesteryl ester production with these particles. These results suggest that Md- and Sm-LpA-I may actively participate in cellular cholesterol removal and cholesterol esterification in plasma and HDL, while Lg-LpA-I may regulate these functions of Md- and Sm-LpA-I.
authors.affiliation: Department of Pediatrics, Kumamoto University School of Medicine, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Ohta
authors.forename: K
authors.initials: K
authors.lastname: Saku
authors.forename: K
authors.initials: K
authors.lastname: Takata
authors.forename: R
authors.initials: R
authors.lastname: Nakamura
authors.forename: Y
authors.initials: Y
authors.lastname: Ikeda
authors.forename: I
authors.initials: I
authors.lastname: Matsuda
mesh_terms: D000293:Adolescent; D000328:Adult; D000818:Animals; D016632:Apolipoprotein A-I / Q000097:blood*; D016633:Apolipoprotein A-II / Q000097:blood*; D002784:Cholesterol / Q000097:blood* / Q000378:metabolism; D002788:Cholesterol Esters / Q000097:blood*; D008076:Cholesterol, HDL / Q000097:blood; D005260:Female; D005487:Foam Cells / Q000378:metabolism*; D006801:Humans; D008075:Lipoproteins, HDL / Q000097:blood*; D008297:Male; D051381:Rats; D017208:Rats, Wistar
chemical_list: D016632:Apolipoprotein A-I; D016633:Apolipoprotein A-II; D002788:Cholesterol Esters; D008076:Cholesterol, HDL; D008075:Lipoproteins, HDL; D002784:Cholesterol