The regenerative capacity of adult human tissues and organs is
limited, but recent developments have seen the advent of promising new technologies for regenerative therapy. The human heart is of particular interest for regenerative medicine, as cardiac tissue damage is repaired by the formation of rigid scar tissue, which causes inevitable structural changes and progressive functional decline leading to heart failure. Cardiac regenerative medicine aims to prevent scar formation or replace existing scars to halt or reverse adverse remodeling and therapeutic approaches include the use of biomaterials, gene therapies, delivery of growth factors and (stem) cell therapies. Regenerative therapies, however, face significant obstacles in a hostile microenvironment. While the early immune response to a myocardial infarct is essential to ensure tissue integrity and to avoid fatal cardiac rupture, excessive activation of endogenous repair mechanisms may lead to ongoing inflammation, fibrosis and sustained autoimmune-mediated tissue damage. Anti-cardiac auto-reactivity of the adaptive immune system has been suggested to be involved in structural remodeling, functional decline and the development of heart failure. It is, therefore, crucial to first understand the endogenous response to cardiac tissue damage and how to restore immune tolerance to cardiac tissue, before additional regenerative therapies can achieve their full potential.