Lanone et al. (2002) demonstrated that MMP-12 can accelerate IL-13-induced inflammatory infiltration whereas MMP-12-deficient macrophages showed diminished proteolytic activity and migration (Shipley et al., 1996). Consistent with these observations, a deficiency in MMP-12 gene attenuated calcium chloride-induced aneurysm growth with less infiltration by macrophages in MMP-12 KO mice (Longo et al., 2005) although there was no effect on the elastase-infusion model (Pyo et al., 2000). This evidence concerns the gene IL13 and aneurysm.