Shear Stress and Angiotensin II in the Development and Localization of Abdominal Aortic Aneurysms

Abdominal aortic aneurysms (AAAs) develop in the infrarenal aorta of humans and in the suprarenal aorta of apoE^−/− mice infused with angiotensin II (AngII). Oscillatory wall shear stress in the infrarenal human abdominal aorta is driven by the flow to the gastric arteries, the lumbar curvature and the capacitance of the lower extremities [1]. Two of these factors, the lumbar curvature and the capacitance of the lower extremities, are significantly different in mice than in humans. Therefore, we hypothesized that the differences in localization of AAAs between species is explained by differences in the pattern of wall shear stress via the shear-regulated modulation of inflammatory pathways involving AngII.