CTSK and cardiac hypertrophy: CatK knockout mouse is capable of mitigating high-fat diet-induced cardiac hypertrophy and contractile dysfunction, indicating that cathepsin K contributes to the development of obesity-associated cardiac hypertrophy (Hua et al. 2013); CatK knockout also alleviates age-related decline in cardiac function via suppressing apoptosis (Hua et al. 2015).