title: Cholesteryl ester flux from HDL to VLDL-1 is preferentially enhanced in type IIB hyperlipidemia in the postprandial state.
abstract: Postprandial triglyceride-rich lipoproteins (TRL) exert proatherogenic effects at the arterial wall, including lipid deposition. Following consumption of a mixed meal (1200 kcal), plasma-mediated cellular free cholesterol (FC) efflux, lecithin:cholesterol acyltransferase (LCAT), and cholesteryl ester transfer protein (CETP) activities were determined in subjects (n = 12) displaying type IIB hyperlipidemia and compared with those in a normolipidemic control group (n = 14). The relative capacity of plasma to induce FC efflux from Fu5AH cells via the SR-BI receptor was significantly increased 4 h postprandially (+23%; P < 0.005) in the type IIB group, whereas it remained unchanged for postprandial plasma from normolipidemic subjects. LCAT activity was significantly elevated 2 h postprandially in both the IIB and control groups, (+46% and +36%, respectively; P < 0.005 vs. respective baseline value). In type IIB subjects, total cholesteryl ester (CE) mass transfer from HDL to total TRL [chylomicrons (CMs) + VLDL-1 + VLDL-2 + IDL] increased progressively from 15 +/- 2 micro g CE/h/ml at baseline to 28 +/- 2 micro g CE transferred/h/ml (+87%; P = 0.0004) at 4 h postprandially. CE transfer to CMs and VLDL-1 was preferentially stimulated (2.6-fold and 2.3-fold respectively) at 4 h in IIB subjects and occurred concomitantly with elevation in mass and particle number of both CMs (2.3-fold) and VLDL-1 (1.3-fold). Furthermore, in type IIB subjects, CETP-mediated total CE flux over the 8 h postprandial period from HDL to potentially atherogenic TRL was significantly enhanced, and notably to VLDL-1 (32-fold elevation; P < 0.005), relative to control subjects. Such CE transfer flux was reflected in a significant postprandial increase in CE-TG ratio in both CMs and VLDL-1 in type IIB plasmas. In conclusion, HDL-CE is preferentially targeted to VLDL-1 via the action of CETP during alimentary lipemia, thereby favoring formation and accumulation of atherogenic CE-rich remnant particles.
mesh_terms: D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D002352:Carrier Proteins / Q000494:pharmacology; D053480:Cholesterol Ester Transfer Proteins; D002788:Cholesterol Esters / Q000097:blood*; D008076:Cholesterol, HDL / Q000097:blood*; D015243:Cholesterol, VLDL / Q000097:blood*; D006023:Glycoproteins; D006801:Humans; D006938:Hyperlipoproteinemia Type II / Q000097:blood*; D007700:Kinetics; D008074:Lipoproteins / Q000097:blood; D008297:Male; D008875:Middle Aged; D007862:Phosphatidylcholine-Sterol O-Acyltransferase / Q000097:blood; D019518:Postprandial Period; D014280:Triglycerides / Q000097:blood
chemical_list: C506642:CETP protein, human; D002352:Carrier Proteins; D053480:Cholesterol Ester Transfer Proteins; D002788:Cholesterol Esters; D008076:Cholesterol, HDL; D015243:Cholesterol, VLDL; D006023:Glycoproteins; D008074:Lipoproteins; D014280:Triglycerides; D007862:Phosphatidylcholine-Sterol O-Acyltransferase