TGFB1 and heart failure: 4 TGF-β1 signaling has broad-ranging effects that may affect cell growth, differentiation and the production of extracellular matrix (ECM) proteins.5, 6 Elevated TGF-β1 is observed in post-MI rat heart7 and is associated with fibroblast-to-myofibroblast phenoconversion and concomitant activation of canonical Smad signaling.8 The result is a proliferation of myofibroblasts, which then leads to inappropriate deposition of fibrillar collagens, impaired cardiac function and, ultimately, heart failure.9, 10