Furthermore, by searching the database, we can easily find that, in the pressure overload model of heart disease, MMP2-deficient mice showed reduced myocardial hypertrophy and fibrosis (Matsusaka et al., 2006) while MMP9 deficiency partially improved myocardial hypertrophy and fibrosis following pressure overload (Heymans et al., 2005). Here, MMP9 is linked to cardiac hypertrophy.