MMP9 and cardiac hypertrophy: Our experiments examined the concentration of matrix metalloproteinase-1 (MMP-1)—also known as interstitial collagenase—which is known to degrade collagen fibers, and two gelatinases—MMP-2 and MMP-9—which participate in collagen cleavage in several cardiovascular diseases including hypertension [29], heart ischemia [30] and cardiac hypertrophy during pressure overload [31].