title: Pharmacodynamic and pharmacokinetic analysis of apoE4 [L261A, W264A, F265A, L268A, V269A], a recombinant apolipoprotein E variant with improved biological properties.
abstract: Physiological levels of wild-type (wt) apolipoprotein E (apoE) in plasma mediate the clearance of cholesterol-rich atherogenic lipoprotein remnants while higher than normal plasma apoE concentrations fail to do so and trigger hypertriglyceridemia. This property of wt apoE reduces significantly its therapeutic value as a lead biological for the treatment of dyslipidemia. Recently, we reported the generation of a recombinant apoE variant, apoE4 [L261A, W264A, F265A, L268A, V269A] (apoE4mut1) with improved biological functions. Specifically, in apoE-deficient (apoE(-/-)) mice this variant can normalize high plasma cholesterol levels without triggering hypertriglyceridemia, even at supraphysiological levels of expression. In the present study we performed pharmacodynamic and pharmacokinetic analysis of apoE4mut1 in experimental mice. Using adenovirus-mediated gene transfer in LDL receptor deficient (LDLr(-/-)) mice, we show that the cholesterol lowering potential of apoE4mut1 is dependent on the expression of a functional classical LDLr. Bolus infusion of apoE4mut1-containing proteoliposomes in apoE(-/-) mice fed western-type diet for 6 weeks indicated that exogenously synthesized apoE4mut1 maintains intact its ability to normalize the high cholesterol levels of these mice with a maximum pharmacological effect obtained at 10h post-treatment. Interestingly, plasma cholesterol levels remained significantly reduced up to 24h following intravenous administration of apoE4mut1 proteoliposomes. Measurements of plasma apoE levels indicated that apoE4mut1 in the form of proteoliposomes used in the study has a half-life of 15.8h. Our data suggest that purified apoE4mut1 may be an attractive new candidate for the acute correction of hypercholesterolemia in subjects expressing functional LDL receptor.
authors.affiliation: Department of Medicine, Pharmacology Unit, University of Patras Medical School, Greece.
authors.forename: Angeliki
authors.initials: A
authors.lastname: Lampropoulou
authors.forename: Vassilis I
authors.initials: VI
authors.lastname: Zannis
authors.forename: Kyriakos E
authors.initials: KE
authors.lastname: Kypreos
mesh_terms: D000818:Animals; D053327:Apolipoprotein E4 / Q000493:pharmacokinetics / Q000494:pharmacology* / Q000627:therapeutic use; D001483:Base Sequence; D002478:Cells, Cultured; D017931:DNA Primers; D004195:Disease Models, Animal; D006937:Hypercholesterolemia / Q000188:drug therapy; D051379:Mice; D018345:Mice, Knockout; D008854:Microscopy, Electron; D060888:Real-Time Polymerase Chain Reaction; D011973:Receptors, LDL / Q000235:genetics; D011994:Recombinant Proteins / Q000493:pharmacokinetics / Q000494:pharmacology / Q000627:therapeutic use
chemical_list: D053327:Apolipoprotein E4; D017931:DNA Primers; D011973:Receptors, LDL; D011994:Recombinant Proteins