Angiotensin I infusion reveals differential effects of angiotensin-converting enzyme in aortic resident cells on aneurysm formation

Background: Angiotensin (Ang)I is cleaved by angiotensin-converting enzyme (ACE) to generate AngII. The purpose of this study was to determine the roles of ACE in endothelial and smooth muscle cells in aortic aneurysms. Methods and Results: AngI infusion led to thoracic and abdominal aortic aneurysms in low-density lipoprotein receptor-deficient mice, which were ablated by ACE inhibition. Endothelial or smooth muscle cell-specific ACE deletion resulted in reduction of AngI-induced thoracic, but not abdominal, aortic dilatation. Conclusions: AngI infusion causes thoracic and abdominal aortic aneurysms in mice. ACE in aortic resident cells has differential effects on AngI-induced thoracic and abdominal aortic aneurysms.