SIRT1 ablation in VSMCs abolished the preventive effect of CR on AAA formation. (A) Representative images showing the macroscopic features of normal aortas and aneurysms of Sirt1flox/flox;Apoe−/− mice and SVKO;Apoe−/− mice in the indicated groups. Bar, 1 mm. (B) Maximal abdominal aortic diameter of Sirt1flox/flox;Apoe−/− mice and SVKO;Apoe−/− mice in the indicated groups. n = 10–25. (C and D) Incidence of AAAs (C) and survival curve (D) of Sirt1flox/flox;Apoe−/− mice and SVKO;Apoe−/− mice after AngII infusion. n = 19–25. (E) Total aortic weight–to-BW ratio of Sirt1flox/flox;Apoe−/− mice and SVKO;Apoe−/− mice in the indicated groups. n = 10–15. (F and G) Representative images of EVG staining of abdominal aortic sections of Sirt1flox/flox;Apoe−/− and SVKO;Apoe−/− mice (F) and semiquantitative analysis of elastin degradation (G). Bars: (top) 200 µm; (bottom) 100 µm. n = 6–8. All values are shown as the means ± SEM. *, P < 0.05; **, P < 0.01; ***, P < 0.001. P-values were obtained using a Fisher’s exact test (C), by a log-rank (Mantel-Cox) test (D), by one-way ANOVA plus a Bonferroni test (G), or by a Kruskal-Wallis test plus a Dunn’s multiple comparison test (B and E). F/F, flox/flox.