Abstract 116: Simvastatin Affects Monocyte Adhesion and Infiltrative Activity in Patients With Abdominal Aortic Aneurysms

Purpose: The pleiotropic effects of statin drugs on reducing inflammation have been well regarded in decreasing AAA expansion. We hypothesize that increased monocyte activity plays a central role in AAA formation and expansion. This study examines whether statins can prevent monocyte cell adhesion, transmigration, and matrix metalloproteinase (MMP) and inhibitor (TIMP) concentrations in AAA patients compared to non-AAA patients. Methods: Peripheral blood was collected for monocyte and serum isolation from control (n=4) and AAA (n=8) patients. Monocyte adhesion and transmigration were assessed under untreated, statin treated, and statin + mevalonate (statin inhibitor) treated conditions in vitro. Luminex assays determined MMP and TIMP concentrations from cell culture and patient serum. Results: Untreated AAA patient monocytes showed higher levels of adhesion (p=0.05) and transmigration (p=0.04) compared to control subjects (Figure 1A & 1B). Statin treatment caused a decrease in AAA monocyte adherence to the endothelium (p=0.03) and high concentrations of mevalonate reversed statin treatment effects (p=0.04) (Figure 1A). A similar trend was noted in monocyte transmigration (Figure 1B). Higher concentrations of MMP-9 were found in AAA patient serum compared to controls (p=0.01) (Figure 1C). TIMP-4 concentration were decreased in AAA patients compared to controls (p=0.02) (Figure 1D). Conclusions: Statins reduce monocyte interaction with the endothelium in vitro, leading to decreased levels of MMP-9 and increased levels of TIMP-4, implying a possible mechanism by which statins reduce AAA expansion.