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Atherosclerosis and Lipoproteins |
From the Department of Nutrition (C.Z., F.M.S.), Harvard School of Public Health, Boston, Mass; and the Department of Medicine (S.J.M., J.D.B.), Division of Metabolism, Endocrinology, and Nutrition, University of Washington, Seattle, Wash.
Correspondence to Dr Frank M. Sacks, Department of Nutrition, Harvard School of Public Health, 665 Huntington Avenue, Boston MA 02115. E-mail fsacks{at}hsph.harvard.edu
Objectives Experiments in cells and animal models show that lipoprotein lipase (LpL) bound to apolipoprotein (apo)B lipoproteins enhances their uptake by receptor mediated pathways. It is unknown whether this pathway is important in humans.
Methods and Results ApoB lipoproteins with LpL were isolated from normal subjects after oral fat loading by immunoaffinity chromatography and were further separated into apoB100 and apoB48 lipoproteins. Postprandially, apoB lipoproteins with LpL had significantly greater increases (4- to 10-fold) and faster rates of clearance (5- to 8-fold) percentage-wise than those without LpL. apoB lipoproteins with LpL had enhanced clearance regardless of whether they also contained apoE. LpL was particularly important for the clearance of apoB48 lipoproteins, of which 25% (range, 11% to 31%) could be removed from circulation together with LpL during the postprandial state. apoB lipoproteins with LpL were larger in size and were enriched in triglyceride, cholesterol, and apoE compared with those without LpL. However, neither size nor apoE content explained the faster clearance rates of LpL-containing lipoproteins.
Conclusion Plasma LpL may act like an apolipoprotein to enhance the clearance of apoB lipoproteins in humans, a mechanism particularly important for intestinal lipoproteins in the postprandial state.
We studied the role of lipoprotein lipase (LpL) in the metabolism of plasma apoB lipoproteins. Postprandially, apoB lipoproteins with LpL had significantly greater increases and faster rates of clearance. The results suggest plasma LpL may act like an apolipoprotein and enhance the clearance from plasma of apoB lipoproteins.
Key Words: lipoprotein lipase ApoB lipoproteins apolipoprotein E postprandial response dietary fats
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C. Zheng, K. Ikewaki, B. W. Walsh, and F. M. Sacks Metabolism of apoB lipoproteins of intestinal and hepatic origin during constant feeding of small amounts of fat J. Lipid Res., August 1, 2006; 47(8): 1771 - 1779. [Abstract] [Full Text] [PDF] |
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