ANPEP and Hypertension: In the model of subacute CVB3 myocarditis, APN-KO mice exhibited a lower level of MMP-9 synthesized by cardiac fibroblasts, which impaired the collagen cleavage during the myocardium injury [183].Yan et al. showed that patients affected by hypertension with a lower level of adiponectin (resulting from genetic polymorphism) were predisposed to enhanced cardiac fibrosis [184].