Animal studies showed that oxidized lipoproteins promote recruitment of inflammatory cells into the elastic media and adventitia of the aortic wall.[31] In vitro studies reported an inverse association between statin use and the activity of matrix metalloproteinase-9, a biomarker for AAA development.[32] Additionally, clinical trials have shown that statin use slows AAA growth.[32] These findings may potentially support a causal pathway between TC or LDL cholesterol and AAA risk; however, statins may prevent AAA by reducing inflammation as well.[32]. The gene discussed is MMP9; the disease is triple-A syndrome.