Smoking promotes pathogenesis of aortic aneurysm through the 5-lipoxygenase pathway.

Smoking has been known as a risk factor for aortic aneurysm. 5-Lipoxygenase is the key enzyme in leukotriene biosynthesis and catalyzes initial steps in the conversion of arachidonic acid to these biologically active lipid mediators, which are known to exert proinflammatory effects in vivo. Smoking can induce 5-lipoxygenase expression in colon neoplasm, and may activate the 5-lipoxygenase pathway also in aortic tissue. 5-Lipoxygenase has a role in promoting the formation of aneurysms through potential plasma macrophage inflammatory protein-1alpha and -2 chemokine-dependent inflammatory circuits involving both myeloid and endothelial cells. Therefore, smoking may promote pathogenesis of aortic aneurysm through the 5-lipoxygenase pathway.