Aortic aneurysms as a source of circulating interleukin-6

In keeping with the inflammatory paradigm of abdominal aortic aneurysm (AAA) pathophysiology, in vitro studies suggest that aneurysms secrete the proinflammatory cytokine interleukin-6 (IL-6). Circulating IL-6 levels are higher in patients with AAA with elevated circulating IL-6 an independent risk factor for cardiovascular mortality. To investigate whether aneurysms secrete IL-6 into the circulation, arterial IL-6 was measured from within the aorta in three groups of patients undergoing endovascular procedures; 27 AAA, 10 thoracic aneurysms (TA), and 15 controls. Overall, IL-6 was higher in the aneurysm groups (P < 0.0008) with significant rises corresponding to positions downstream to the aneurysm in both AAA and TA. There were no significant differences in IL-6 with aortic position in the control group. These data support the hypothesis that aneurysms secrete IL-6 into the circulation and may account for the high cardiovascular mortality observed in patients with aneurysms.