Preferential clearance of apoB-48-containing lipoproteins after heparin-induced lipolysis is modulated by lipoprotein lipase activity1

Abstract

The acute effects of intravenous heparin administration (50 U/kg body weight) on apolipoprotein (apo)B-48 and apoB-100-containing lipoproteins in relation to postheparin lipase activities were studied in ten healthy normolipidemic volunteers. Five subjects returned to receive sham injections with saline. Lipoproteins were separated from plasma by density gradient ultracentrifugation at baseline, 3, and 20 min postheparin. ApoB-48 and apoB-100 in d 140 mU/mL), comparable percentual reductions for apoB-48 and apoB-100 were seen. Pharmacokinetic analysis revealed first-order kinetics for the clearance of apoB-48 in d < 1.006 g/mL fractions, but zero-order kinetics for apoB-100 clearance. Under conditions of artificially enhanced lipolysis, the first catabolic step of apoB-48-containing lipoproteins and hepatic VLDL showed different pharmacokinetics. ApoB-48-containing lipoproteins were the preferred substrate for LPL, and only when abundant LPL was present, clearance of hepatic VLDL occurred.—van Beek, A. P., H. H. J. J. van Barlingen, F. C. de Ruijter-Heijstek, H. Jansen, D. W. Erkelens, G. M. Dallinga-Thie, and T. W. A. de Bruin. Preferential clearance of apoB-48-containing lipoproteins after heparin-induced lipolysis is modulated by lipoprotein lipase activity.

Keywords

• chylomicron
• apoB-100
• triglyceride-rich lipoproteins
• hepatic lipase
• chylomicron-remnant clearance
• pharmacokinetics