ABSTRACT
Introduction Owing to the negligible ability of the adult heart to replace damaged myocardium, an intense search has been initiated to find progenitor cells that can be used as a replacement therapy. Despite large research projects and huge investments, controversy remains as to the interpretation and efficiency of regeneration or transplantation strategies within the damaged heart. What is, however, clear is that the regenerative capacity of the “normal” adult human myocardium is insufficient to maintain cardiac function upon loss of cardiomyocytes. Moreover, irrespective of the source of cells introduced into the damaged heart, cardiomyocyte differentiation is in no way sufficient to replace dysfunctional myocardium. Trials carried out so far have often noted a certain level of physiological improvement, though the exact nature and reason for this has not yet been identified. From an optimistic point of view, it is defendable to conclude that replacement therapy is a viable approach to cure the diseased heart. One means of advancing these replacement therapies to a point where it should be plausible to efficiently replenish the diseased heart with functional viable cardiomyocytes is by advancing our current knowledge on the cellular and signaling pathways involved in cardiogenesis. Although developmental biologists have identified many individual components of this intricate process, our understanding of the integration of the various components is limited. In this chapter we will discuss the formation of the developing heart,
with respect to the different cell types that contribute to the heart and the main signaling pathways involved in cardiogenesis (Figure 1.1).
