Generation of Human Ventricular Cardiomyocytes Derived from Induced Pluripotent Stem Cells for studying of heart disease

Obtaining cardiomyocytes derived from induced pluripotent stem cells (hiPSC-CMs) is essential for pathophysiological studies and the development of new cardiovascular therapies. Often, hiPSC-CMs exhibit immature characteristics, similar to fetal cardiomyocytes, with poor sarcomeric organization, reduced mitochondrial oxidative capacity, altered calcium dynamics, and a short action potential duration, limiting their application in pharmacological and toxicological research. Metabolic modulation has been explored as a maturation strategy to promote a phenotype closer to mature cardiomyocytes. Furthermore, differentiation protocols to obtain a more homogeneous hiPSC-CM culture, such as left ventricular cardiomyocytes, are under development. The role of ionic currents, particularly the sodium current (INa), is essential for the generation and propagation of the action potential (AP). Given this scenario, this study aimed to establish an effective differentiation and maturation protocol to obtain a homogeneous and functional population of hiPSC-CMs. The hiPSCs were cultured to test two cardiomyocyte differentiation strategies: a standard protocol, named Protocol 1, and a protocol to obtain a higher percentage of left ventricular cardiomyocytes, Protocol 2. Functional analyses using the patch-clamp technique were performed to evaluate the cells functionally. The results showed that 90 days in culture were necessary to obtain hiPSC-CMs with an AP waveform resembling that of an adult cell. In contrast, using Protocol 2, it was possible to obtain hiPSC-CMs similar to those from Protocol 1 in only 30 days, considering the AP duration. Although the older protocol demonstrated a higher dV/dt (maximum AP depolarization rate), the LV protocol produced cells with an electrophysiological profile closer to that of a mature human AP, considering AP duration. In conclusion, Protocol 2 demonstrated efficiency in generating mature hiPSC-CMs in a shorter timeframe. This validates its potential as a robust platform for in vitro cardiovascular research and channelopathy studies.