These studies provide evidence that oxidative stress generated by recombinant d-amino acid oxidase expressed in vascular endothelial cells leads to abdominal aortic aneurysm formation, hypertension, and premature death in DAAO-TGTie2 transgenic mice fed d-alanine (Figures 1 and 2). This evidence concerns the gene DAO and abdominal aortic aneurysm.