TGFB1 and atrial fibrillation: EAT releases pro-fibrotic factors, such as TGF-β1, the adipokine activin A, a member of the TGF-β superfamily and MMP2, MMP7, key regulators of extra-cellular matrix activity, that are up-regulated during AF, thereby contributing to atrial collagen deposition, fibrosis and remodeling (114–116).