title: Evaluation of Antiatherogenic Properties of Ezetimibe Using3H-Labeled Low-Density-Lipoprotein Cholesterol and99mTc-cAbVCAM1-5 SPECT in ApoE-/-Mice Fed the Paigen Diet.
abstract: The addition of ezetimibe, an intestinal cholesterol absorption inhibitor, to statin therapy has recently shown clinical benefits in the Improved Reduction of Outcomes: Vytorin Efficacy International Trial by reducing low-density-lipoprotein (LDL) cholesterol levels more than statin therapy alone. Here, we investigated the mechanisms by which inhibition of intestinal cholesterol absorption might contribute to the clinically observed reduction in cardiovascular events by evaluating its effect on inflammatory plaque development in apolipoprotein E-/-mice.Methods:Apolipoprotein E-/-mice were fed the Paigen diet (1.25% cholesterol, 0.5% cholic acid, and 15% fat) without or with ezetimibe (7 mg/kg/d) for 6 wk. In a first set of mice (n= 15), we intravenously injected3H-cholesteryl oleate-labeled human LDL to test whether ezetimibe promotes LDL-derived cholesterol fecal excretion. In a second set (n= 20), we used the imaging agent99mTc-cAbVCAM1-5 to evaluate expression of an inflammatory marker, vascular cell adhesion molecule 1 (VCAM-1), in atherosclerotic plaques. In a third set (n= 21), we compared VCAM-1 expression with99mTc-cAbVCAM1-5 uptake in various tissues.Results:Mice treated with ezetimibe showed a 173% higher LDL-cholesteryl ester plasma disappearance rate (P< 0.001 vs. control) after3H-cholesteryl oleate-labeled LDL injection. At 96 h after injection, the hepatic fraction of3H-tracer was 61% lower in mice treated with ezetimibe (P< 0.001). Meanwhile, LDL-derived3H-cholesterol excretion in the feces was 107% higher (P< 0.001). The antiatherogenic effect of ezetimibe monitored by99mTc-cAbVCAM1-5 SPECT showed a 49% reduction in aortic tracer uptake (percentage injected dose per cubic centimeter, 0.95 ± 0.04 vs. 1.87 ± 0.11;P< 0.01). In addition to hypercholesterolemia, the proinflammatory Paigen diet significantly increased VCAM-1 expression with respect to the control group in various tissues, including the aorta, and this expression correlated strongly with99mTc-cAbVCAM1-5 uptake (r= 0.75;P< 0.05).Conclusion:Inhibition of intestinal cholesterol absorption with ezetimibe promotes antiatherosclerotic effects through increased LDL cholesterol catabolism and LDL-derived cholesterol fecal excretion and reduces inflamed atherosclerotic plaques. These mechanisms may contribute to the benefits of adding ezetimibe to a statin therapy.
authors.affiliation: INSERM U1039 Radiopharmaceutiques Biocliniques, Grenoble, France.|UGA, Université Grenoble Alpes, Grenoble, France.|Advanced Accelerator Applications, Saint-Genis-Pouilly, France.
authors.forename: Laurent S
authors.initials: LS
authors.lastname: Dumas
authors.affiliation: Physiogenex, Labège, France.
authors.forename: François
authors.initials: F
authors.lastname: Briand
authors.affiliation: INSERM U1039 Radiopharmaceutiques Biocliniques, Grenoble, France.|UGA, Université Grenoble Alpes, Grenoble, France.|Physiogenex, Labège, France.
authors.forename: Romain
authors.initials: R
authors.lastname: Clerc
authors.affiliation: Physiogenex, Labège, France.
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Brousseau
authors.affiliation: INSERM U1039 Radiopharmaceutiques Biocliniques, Grenoble, France.|UGA, Université Grenoble Alpes, Grenoble, France.
authors.forename: Christopher
authors.initials: C
authors.lastname: Montemagno
authors.affiliation: INSERM U1039 Radiopharmaceutiques Biocliniques, Grenoble, France.|UGA, Université Grenoble Alpes, Grenoble, France.
authors.forename: Mitra
authors.initials: M
authors.lastname: Ahmadi
authors.affiliation: INSERM U1039 Radiopharmaceutiques Biocliniques, Grenoble, France.|UGA, Université Grenoble Alpes, Grenoble, France.
authors.forename: Sandrine
authors.initials: S
authors.lastname: Bacot
authors.affiliation: INSERM U1039 Radiopharmaceutiques Biocliniques, Grenoble, France.|UGA, Université Grenoble Alpes, Grenoble, France.
authors.forename: Audrey
authors.initials: A
authors.lastname: Soubies
authors.affiliation: INSERM U1039 Radiopharmaceutiques Biocliniques, Grenoble, France.|UGA, Université Grenoble Alpes, Grenoble, France.
authors.forename: Pascale
authors.initials: P
authors.lastname: Perret
authors.affiliation: INSERM U1039 Radiopharmaceutiques Biocliniques, Grenoble, France.|UGA, Université Grenoble Alpes, Grenoble, France.
authors.forename: Laurent M
authors.initials: LM
authors.lastname: Riou
authors.affiliation: ICMI, Vrije Universiteit Brussel, Brussels, Belgium; and.
authors.forename: Nick
authors.initials: N
authors.lastname: Devoogdt
authors.affiliation: ICMI, Vrije Universiteit Brussel, Brussels, Belgium; and.
authors.forename: Tony
authors.initials: T
authors.lastname: Lahoutte
authors.affiliation: INSERM U1039 Radiopharmaceutiques Biocliniques, Grenoble, France.|UGA, Université Grenoble Alpes, Grenoble, France.|CHRU Grenoble, Hôpital Michallon, Grenoble, France.
authors.forename: Gilles
authors.initials: G
authors.lastname: Barone-Rochette
authors.affiliation: INSERM U1039 Radiopharmaceutiques Biocliniques, Grenoble, France.|UGA, Université Grenoble Alpes, Grenoble, France.|CHRU Grenoble, Hôpital Michallon, Grenoble, France.
authors.forename: Daniel
authors.initials: D
authors.lastname: Fagret
authors.affiliation: INSERM U1039 Radiopharmaceutiques Biocliniques, Grenoble, France.|UGA, Université Grenoble Alpes, Grenoble, France.
authors.forename: Catherine
authors.initials: C
authors.lastname: Ghezzi
authors.affiliation: Physiogenex, Labège, France.
authors.forename: Thierry
authors.initials: T
authors.lastname: Sulpice
authors.affiliation: INSERM U1039 Radiopharmaceutiques Biocliniques, Grenoble, France alexis.broisat@inserm.fr.|UGA, Université Grenoble Alpes, Grenoble, France.
authors.forename: Alexis
authors.initials: A
authors.lastname: Broisat
mesh_terms: D000818:Animals; D000924:Anticholesteremic Agents / Q000008:administration & dosage; D001057:Apolipoproteins E / Q000235:genetics; D050197:Atherosclerosis / Q000000981:diagnostic imaging* / Q000188:drug therapy* / Q000378:metabolism; D008078:Cholesterol, LDL; D059305:Diet, High-Fat; D016903:Drug Monitoring; D000069438:Ezetimibe / Q000008:administration & dosage*; D005243:Feces; D005260:Female; D007553:Isotope Labeling; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008822:Mice, Transgenic; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013667:Technetium; D015899:Tomography, Emission-Computed, Single-Photon; D016896:Treatment Outcome; D014316:Tritium
chemical_list: D000924:Anticholesteremic Agents; D001057:Apolipoproteins E; D008078:Cholesterol, LDL; D014316:Tritium; D013667:Technetium; D000069438:Ezetimibe
keywords: 99mTc-cAbVCAM1–5; LDL-cholesterol catabolism; VCAM-1; atherosclerosis; ezetimibe