Lysyl hydroxylase 1 (LH1) deficiency triggers dissecting abdominal aortic aneurysm (AAA) formation following 4 weeks of angiotensin II (Ang II) infusion. A, Representative morphology of the aortas of wild-type (WT) and procollagen-lysine, 2-oxoglutarate 5-dioxygenase 1 (Plod1)-/- mice. B, The incidence of dissecting AAA and aortic aneurysm rupture in WT and Plod1-/- mice in response to Ang II administration (n = 20). Two-sided fisher's exact test. C, Representative images of transabdominal ultrasound measurements (the lumen is indicated by the yellow line) at day 28 after saline or Ang II infusion. D, Quantification of the abdominal aorta diastolic diameter, pulse-wave velocity (PWV) and distensibility of the aortic wall by ultrasound at day 28 after saline or Ang II infusion (n = 10). E, Representative immunoblotting images of LH1 and quantitative analysis of LH1 expression in the abdominal aortas of WT and Plod1-/- mice after Ang II or saline infusion (n = 6). ND indicates not detected. Student's unpaired two-tailed t-test. F, Representative immunostaining images of LH1 (red), elastin (green) and DAPI (blue) in the abdominal aorta. G, The systolic blood pressure of each group at day 28 after saline or Ang II infusion (n = 10). Two-way ANOVA followed by the Bonferroni post hoc test was used in D and G.