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Apolipoprotein‐B subclasses as acceptors of cholesteryl esters transferred by CETP
Author(s) -
Lee D. M.,
Alaupovic P.,
KnightGibson C.,
Bagdade J. D.
Publication year - 2008
Publication title -
european journal of clinical investigation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.164
H-Index - 107
eISSN - 1365-2362
pISSN - 0014-2972
DOI - 10.1111/j.1365-2362.2008.02001.x
Subject(s) - chemistry , apolipoprotein b , subclass , very low density lipoprotein , cholesteryl ester , triglyceride , lipoprotein , acceptor , lipolysis , biochemistry , cholesterol , biology , antibody , genetics , physics , adipose tissue , condensed matter physics
Background Five apolipoprotein (apo)‐defined apoB‐containing lipoprotein (Lp) subclasses designated LpB, LpB:C, LpB:E, LpB:C:E and LpA‐II:B:C:D:E are present in human plasma. This study was to determine whether these subclasses functioned equally as acceptors of cholesteryl esters (CE) transferred from high‐density lipoproteins (HDL) by CE transfer protein in healthy subjects with normal and mildly increased plasma triglyceride (TG) levels. Materials and methods After 4 h incubation of plasma from 14 subjects at 37 °C, apoB‐containing lipoproteins were separated from HDL by heparin‐Mn ++ precipitation and fractionated by immunochemical methods into these five subclasses. The neutral lipid (NL) composition for each subclass was measured by gas chromatography (GC) and compared between 0 h and 4 h. A subclass was considered to be a CE acceptor if its CE content increased more than 5% at 4 h and a non‐acceptor if no change was observed. Results Employing the above definition, TG‐rich LpB:C and LpB:E + LpB:C:E functioned as CE acceptors and TG‐poor LpB and LpA‐II:B:C:D:E as non‐acceptors. Both LpB:C and LpB:E + LpB:C:E could only actively accept CE as long as they retained their TG‐rich character and displayed neutral lipid profiles similar to those of very low‐density lipoproteins (VLDL) and intermediate density lipoproteins (IDL). When, as a result of lipolysis their TG content dropped below 25%, they ceased to function as CE acceptors. In subjects with elevated plasma TG, LpB:C was the dominant CE acceptor, a condition that may have pro‐atherogenic consequences. Conclusions Among the apoB‐containing particles, LpB:C and LpB:C:E + LpB:E functioned as CE acceptors while LpB and LpA‐II:B:C:D:E did not.