MMP9 and cardiac hypertrophy: Inflammatory mediators, especially tumor necrosis factor- (TNF-) α, interleukin- (IL-) 6, IL-1β, and IL-18, impair cardiac function by promoting cardiomyocyte apoptosis, cardiac hypertrophy, inflammatory response, and matrix metalloproteinase-9 (MMP-9) activity; their plasma levels are increased in heart failure in association with disease severity [3–5].