Apoe−/− and Apoe−/−/IDO−/− mice were reconstituted with Apoe−/− or Apoe−/−/IDO+/+ bone marrow cells, followed by 4 weeks of saline or AngII infusion (1000 ng/min per kg). (a) Representative photographs showing the macroscopic features of AngII-induced aneurysms. Arrows indicate typical AAA. (b–d) The incidence of AngII-induced AAA (b), maximal abdominal aortic diameter (c), and total aortic weight (d) in AngII-infused mice reconstituted with IDO+/+ or IDO−/− bone marrow cells. n=10–15 per group. BM, bone marrow; NS, not significant. *P<0.01 vs. AngII-infused Apoe−/− mice reconstituted with Apoe−/−/IDO+/+ bone marrow cells. P values were obtained by a Fisher exact test in b and by a two-way ANOVA with following Bonferroni’s multiple comparisons in c and d. The error bars in c and d are s.e.m.