Exploring hiPSC-CM replacement therapy in ischemic hearts.

Ischemic heart disease is one of the leading causes of heart failure and death worldwide. The loss of cardiomyocytes following a myocardial infarction drives the remodeling process, which, in most cases, ultimately leads to heart failure. Since the available treatment options only slow down the remodeling process without tackling the causes of heart failure onset (i.e., cardiomyocyte loss and inability of the remaining cardiomyocytes to enter the cell cycle and regenerate the heart), in the last two decades, cardiovascular research focused on finding alternative solutions to regenerate the heart. So far, the investigated approaches include a variety of methods aiming at manipulation of non-coding RNAs, such as long non-coding RNA (lncRNA), circular RNA (circRNA), and microRNA (miRNA), and growth factors to enable the cardiomyocytes to re-enter the cell cycle, direct reprogramming of fibroblasts into cardiomyocytes (CM), and CM replacement therapy, all of them with the main goal to replace the loss of cardiomyocytes and restore the heart function. The development of reprogramming protocols from somatic cells to induced pluripotent stem cells (iPSCs) by Yamanaka and Takahashi, along with advancements in differentiation protocols to generate almost pure populations of induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs), has fostered optimism in cardiac regenerative medicine. Despite these advancements, critical concerns arose regarding the survival and retention of the engrafted cells, arrhythmogenicity, and immune response. Over time, much effort has been put into enhancing iPSC-CM therapy with different methods, ranging from anti-apoptotic small molecule-based approaches to tissue engineering. In this review, we discuss the evolution of cardiac cell therapy, highlighting recent advancements and the remaining challenges that must be overcome to translate this promising approach into clinical practice.