Extracellular matrix remodeling includes also activation of collagenolytic enzymes (matrix metalloproteinases) that lead to ventricular dilatation [38], and interestingly, both MMP-2 and MMP-9 gene expressions were increased in (P)RR overexpressing hearts associated with reduced intraventricular septum diastolic and systolic thickness. The gene discussed is MMP9; the disease is Ventriculomegaly.