Resident Macrophages and Their Potential in Cardiac Tissue Engineering.

Many facets of tissue engineered models aim at understanding cellular mechanisms to recapitulate in vivo behavior, to study and mimic diseases for drug interventions, and to provide a better understanding toward improving regenerative medicine. Recent and rapid advances in stem cell biology, material science and engineering, have made the generation of complex engineered tissues much more attainable. One such tissue, human myocardium, is extremely intricate, with a number of different cell types. Recent studies have unraveled cardiac resident macrophages as a critical mediator for normal cardiac function. Macrophages within the heart exert phagocytosis and efferocytosis, facilitate electrical conduction, promote regeneration, and remove cardiac exophers to maintain homeostasis. These findings underpin the rationale of introducing macrophages to engineered heart tissue (EHT), to more aptly capitulate in vivo physiology. Despite the lack of studies using cardiac macrophages in vitro, there is enough evidence to accept that they will be key to making EHTs more physiologically relevant. In this review, we explore the rationale and feasibility of using macrophages as an additional cell source in engineered cardiac tissues.