Metabolic impacts of long-chain fatty acids on cardiomyocyte maturation in neonatal mammalian hearts

Cardiomyocytes are essential models for cardiac disease modeling, drug development, and regenerative therapies. Specifically, human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) have emerged as widely used cellular models with high reproducibility. However, cardiomyocytes generated in vitro tend to remain immature and insufficient in replicating the electrophysiological and mechanical functions of adult cardiomyocytes, limiting the clinical and experimental applications of these models. Thus, various biochemical and biophysical strategies have been explored to promote the maturation of cardiomyocytes, to address these limitations, and more accurately mimic the characteristics of mature cardiomyocytes. This review summarizes recent studies on multiple methodologies employed to induce cardiomyocyte maturation, with a particular emphasis on the role of long-chain fatty acids (LCFAs). The evidence summarized in this review is derived from studies utilizing cardiomyocytes from neonatal mice or rats and hiPSC-CMs. Meanwhile, immature cardiomyocytes have been demonstrated to predominantly rely on glycolysis, transitioning to oxidative phosphorylation through maturation, which enhances electrical stability, contractility, and structural organization. LCFAs play a key role in the cardiomyocyte maturation process by serving as key metabolic factors that generate ATP through mitochondrial β-oxidation, thereby improving metabolic efficiency. Additionally, LCFAs are involved in activating cytoskeletal components and signaling pathways integral to cardiomyocyte contractility. Importantly, studies suggest that when multiple biochemical and biophysical stimuli are simultaneously applied, various aspects of cardiomyocyte maturation are synergistically accelerated. Therefore, future studies focusing on the coordinated application of these regulatory factors are expected to enhance the maturation process, ultimately contributing to the generation of mature cardiomyocytes suitable for regenerative medicine and other advanced applications.