Thrombospondin-1 is the key mediator of dissecting abdominal aortic aneurysm (AAA) pathogenesis in the absence of lysyl hydroxylase 1 (LH1). A, Representative aortas from procollagen-lysine, 2-oxoglutarate 5-dioxygenase 1 (Plod1)-/- mice treated with scrambled peptide (scrb) or TAX2 followed by angiotensin II (Ang II) infusion for 4 weeks. B, Incidence of dissecting AAA and aortic aneurysm rupture in Plod1-/- mice treated with scrb or TAX2 in response to Ang II (n = 20). Two-sided fisher's exact test. C, Representative images of transabdominal ultrasound measurements (the lumen is indicated by the yellow line). D, Quantification of the abdominal aorta diastolic diameter, pulse-wave velocity (PWV) and distensibility of the aortic wall by ultrasound (n = 10). Student's unpaired two-tailed t-test. E, Representative hematoxylin and eosin (H&E)-, Verhoeff-Van Gieson (VVG)-, and Masson trichrome-stained cross-sections of the abdominal aortas of mice. F, Representative immunofluorescence staining of macrophages in the abdominal aorta following Ang II infusion for 2 weeks. The insets show higher magnification images. G, Representative gelatin zymography of abdominal aortas from the indicated groups. H, Representative images of apoptotic cells (upper) and α-SMA expression (lower) in the abdominal aorta.