| Autor: |
Kraaijenhof JM; Department of Vascular Medicine Amsterdam University Medical Centers, Location AMC Amsterdam The Netherlands., Tromp TR; Department of Vascular Medicine Amsterdam University Medical Centers, Location AMC Amsterdam The Netherlands., Nurmohamed NS; Department of Vascular Medicine Amsterdam University Medical Centers, Location AMC Amsterdam The Netherlands.; Department of Cardiology Amsterdam University Medical Centers, Location AMC Amsterdam The Netherlands., Reeskamp LF; Department of Vascular Medicine Amsterdam University Medical Centers, Location AMC Amsterdam The Netherlands., Langenkamp M; Department of Experimental Vascular Medicine Amsterdam University Medical Centers, Location AMC Amsterdam The Netherlands., Levels JHM; Department of Experimental Vascular Medicine Amsterdam University Medical Centers, Location AMC Amsterdam The Netherlands., Boekholdt SM; Department of Cardiology Amsterdam University Medical Centers, Location AMC Amsterdam The Netherlands., Wareham NJ; Medical Research Council (MRC) Epidemiology Unit Cambridge United Kingdom., Hoekstra M; Division of BioTherapeutics, Leiden Academic Centre for Drug Research Leiden University Leiden The Netherlands., Stroes ESG; Department of Vascular Medicine Amsterdam University Medical Centers, Location AMC Amsterdam The Netherlands., Hovingh GK; Department of Vascular Medicine Amsterdam University Medical Centers, Location AMC Amsterdam The Netherlands., Grefhorst A; Department of Experimental Vascular Medicine Amsterdam University Medical Centers, Location AMC Amsterdam The Netherlands. |
| Abstrakt: |
Background ANGPTL3 (angiopoietin-like protein 3) is an acknowledged crucial regulator of lipid metabolism by virtue of its inhibitory effect on lipoprotein lipase and endothelial lipase. It is currently unknown whether and to which lipoproteins ANGPTL3 is bound and whether the ability of ANGPTL3 to inhibit lipase activity is affected by binding to lipoproteins. Methods and Results Incubation of ultracentrifugation-isolated low-density lipoprotein (LDL) and high-density lipoprotein (HDL) fractions from healthy volunteers with recombinant ANGPTL3 revealed that ANGPTL3 associates with both HDL and LDL particles ex vivo. Plasma from healthy volunteers and a patient deficient in HDL was fractionated by fast protein liquid chromatography, and ANGPTL3 distribution among lipoprotein fractions was measured. In healthy volunteers, ≈75% of lipoprotein-associated ANGPTL3 resides in HDL fractions, whereas ANGPTL3 was largely bound to LDL in the patient deficient in HDL. ANGPTL3 activity was studied by measuring lipolysis and uptake of 3 H-trioleate by brown adipocyte T37i cells. Unbound ANGPTL3 did not suppress lipase activity, but when given with HDL or LDL, ANGPTL3 suppressed lipase activity by 21.4±16.4% ( P =0.03) and 25.4±8.2% ( P =0.006), respectively. Finally, in a subset of the EPIC (European Prospective Investigation into Cancer) Norfolk study, plasma HDL cholesterol and amount of large HDL particles were both positively associated with plasma ANGPTL3 concentrations. Moreover, plasma ANGPTL3 concentrations showed a positive association with incident coronary artery disease (odds ratio, 1.25 [95% CI, 1.01-1.55], P =0.04). Conclusions Although ANGPTL3 preferentially resides on HDL, its activity was highest once bound to LDL particles. |
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