For Mmp9, less elastin in the aneurysm wall in women than that in men, and the simultaneous higher level of Mmp-9, suggesting differences in the elastolytic process in abdominal aortic aneurysms between the sexes (Villard et al., 2014); in addition, male mucopolysaccharidosis type I mice have an increased incidence of aortic insufficiency associated with an increase in MMP-12 aortic arch content (Tolar et al., 2009). Here, MMP9 is linked to aortic valve insufficiency.