Abstract 462: Reductions of ApoB-containing Lipoproteins Prevented the Progression of Established Abdominal Aortic Aneurysms in AngII Infused Mice
Background and Objective: We have demonstrated that increased plasma apolipoprotein B (apoB)-containing lipoproteins augment development of AngII-induced abdominal aortic aneurysms (AAAs) in male mice. The purpose of this study was to determine whether plasma apoB-containing lipoproteins also influenced progression of established AAAs during chronic AngII-infusion.
Methods and Results: Male LDL receptor -/- mice fed either a normal (Group 1) or Western (42% calories from saturated fat) diet were infused with AngII (1,000 ng/kg/min) for 28 days to induced AAAs. Maximal luminal diameters of the suprarenal region were compared with baseline after 4 weeks of AngII infusion to determine AAA presence. Mice fed Western diet were stratified by aortic lumen diameter into either a group maintained on Western diet (Group 2) or switched to a normal laboratory diet (Group 3). AngII infusion was continued for another 8 weeks in all 3 groups. Plasma cholesterol concentrations were determined at 4, 6, and 12 weeks of AngII infusion. Mice fed a Western diet for the initial 4 weeks were hypercholesterolemic (260 ± 13 to 1,469 ± 59 mg/dl). Two weeks after Group 3 were returned to normal laboratory diet, plasma cholesterol concentrations were profoundly reduced to 382 ± 22 mg/dl which was maintained for the remaining interval. These reductions were due to decreases in plasma cholesterol concentrations apoB-containing lipoproteins. Luminal diameters of suprarenal aortas were measured at 6 and 12 weeks of AngII infusion by ultrasonography. While luminal expansion progressed in mice fed Western diet, no continuous expansion was detected in mice with established AAAs that were fed normal laboratory diet. Ultrasonic measurements were confirmed at study termination by ex vivo measurements of maximal widths of suprarenal aortas (Group 1 verus 2 versus 3: 1.35 ± 0.04 mm, 3.32 ±0.34 mm, 1.91 ± 0.11 mm, respectively).
Conclusions: Plasma apoB-containing lipoproteins contribute to the progressive expansion of established AAAs in AngII-infused mice.
Author Disclosures: J. Liu: None. H. Lu: None. J. Moorleghen: None. D. Howatt: None. A. Balakrishnan: None. L. Cassia: None. A. Daugherty: None.
- © 2015 by American Heart Association, Inc.