Distribution of cell-derived cholesterol among plasma lipoproteins: a comparison of three techniques.
Three fractionation procedures (immunoaffinity chromatography, two-dimensional nondenaturing electrophoresis, and heparin-agarose affinity chromatography) have been compared in determining the kinetics of free and ester cholesterol transfer in normolipemic native plasma. Similar results were obtained in each case. Cell-derived free cholesterol is initially enriched in high density lipoproteins (HDL) (mainly HDL without apoE); at longer time periods (greater than 10 min) greater proportions are observed in very low density lipoproteins (VLDL) and low density lipoproteins (LDL). The major part of cholesteryl ester (about 90%) was retained in HDL, while VLDL and LDL, which contained about 75% of total cholesteryl ester mass, received only about 10% of cell-derived cholesteryl ester. Within HDL, almost all cholesteryl ester was in the apoE-free fraction. These data provide evidence that lipoprotein free and esterified cholesterol are not at chemical equilibrium in normal plasma, and that cell-derived cholesterol is preferentially directed to HDL. The techniques used had a comparable effectiveness for the rapid fractionation of labile lipoprotein lipid radioactivity.
Francone
O L
OL
Cardiovascular Research Institute, University of California Medical Center, San Francisco, CA 94143.
Fielding
C J
CJ
Fielding
P E
PE
D002478:Cells, Cultured; D005591:Chemical Fractionation; D002784:Cholesterol / Q000097:blood*; D002846:Chromatography, Affinity; D015180:Electrophoresis, Gel, Two-Dimensional; D006801:Humans; D007700:Kinetics; D008074:Lipoproteins / Q000097:blood*; D008075:Lipoproteins, HDL / Q000097:blood
D008074:Lipoproteins; D008075:Lipoproteins, HDL; D002784:Cholesterol