Histopathologic assessment of myocardial regeneration

Cardiac regeneration in the form of cell-based therapy offers hope of becoming the breakthrough technology that transforms the state of cardiac medicine. Before attempting to develop the techniques to assess the effectiveness of myocardial regeneration in humans, researchers must have at least a basic understanding of the human heart in its embryonic, normal, and diseased states. To this end, we provide an overview of the histology of the heart, including the current theories on normal embryogenesis and the histology of normal and ischemic myocardium as visualized by pathologists. Knowledge of the cellular constituents, including the controversial existence of resident cardiac stem and/or progenitor cells, and their actions and interactions in the normal state and under the conditions of myocardial ischemia is also crucial before embarking on the quest for cardiac regeneration. Despite widespread optimism in the success of cell-based therapy, inherent difficulties remain in the identification of effective cell populations proposed for cell-based therapy in the human heart.