PHENOTYPIC CORRECTION OF HYPERCHOLESTEROLEMIA IS APOE-DEFICIENT MICE BY ADENOVIRUS-MEDIATED IN-VIVO GENE-TRANSFER

To investigate the potential use of apoE in gene therapy of hyperlipid emias, an adenoviral vector was constructed that contained the human a poE3 cDNA under the control of the RSV promoter (Av1RE). Transduction of HepG2 cells resulted in the overexpression of human apoE secreted i nto the culture medium. Intravenous injection of 5x10(11) Av1RE vector particles into apoE-deficient mice resulted in expression of human ap oE3 in mouse plasma at levels of 1.2+/-0.4 mu g/mL (mean+/-SEM, n=5) 7 days after injection. Mice injected with the control vector Av1Lacz4 did not express detectable levels of human apoE. Average plasma choles terol concentrations were reduced approximately eightfold from 737.5+/ -118 mg/dL (mean+/-SEM, n=6) to 98.2+/-4.4 mg/dL (mean+/-SEM, n=5) and were unaffected in the control vector group. Expression of human apoE resulted in a shift in the plasma lipoprotein distribution from prima rily VLDL and LDL in the control mice to predominantly HDL in the Av1R E-treated group. Western blot analysis of fast protein liquid chromato graphy-fractionated mouse plasma showed that the human apoE protein wa s associated with VLDL, LDL, and HDL. Correction of the hyperlipidemic condition found in the apoE-knockout mouse strain by direct in vivo g ene transfer establishes the potential of this approach for treatment of hyperlipidemia caused by apoE deficiency or malfunction in human di sease.