ELN and triple-A syndrome: Histopathological characterization was performed using hematoxylin and eosin (H&E), Verhoeff-Van Gieson (VVG), and masson trichrome (MT) stains, as previously described.21 All chemically induced groups showed classic AAA dilation with moderate to severe inflammation and elastin degradation, particularly in the Pap and PPE+Pap groups compared to the saline group (Figure 1D and Extended Figure 2 A-C).