AGT and triple-A syndrome: Putrescine is a polyamine that is synthesized from ornithine via decarboxylation of the amino acid.[12] High concentrations of putrescine have been detected in cancer and inflammatory bowel diseases.[13, 14] Metabolomic phenotyping of experimental animal models of AAA has shown that putrescine is upregulated in the blood and aortas of Ang II‐induced mice;[15] however, the role of putrescine in aortic aneurysms remains unclear.