Oxygen-generating Microparticles Enhance Viability and Functionality of Human Pluripotent Stem Cell-derived Cardiomyocytes for Myocardial Infarction Therapy.

BACKGROUND

Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) represent a promising therapy for myocardial infarction (MI), but their survival is severely limited by the hypoxic infarct environment. The optimal oxygen levels required to maintain the viability and functionality of hiPSC-CMs remain poorly defined. This study aimed to develop a controlled oxygen-delivery system to support engineered heart tissue (EHT) for cardiac regeneration.

METHODS

Oxygen-generating particles (OGPs) were engineered using peroxide (sodium percarbonate) and antioxidant (β-carotene (βCAR)) components encapsulated in PLGA microparticles. The effects of OGPs on hiPSC-CMs were evaluated through oxidative stress assays, cell viability analysis, and contractility measurements. RNA-seq was performed to investigate gene expression changes in hiPSC-CMs in response to OGPs and hypoxic stress. hiPSC-CMs combined with OGPs were encapsulated in a 3D hydrogel to generate oxygen-releasing engineered heart tissue (OR-EHT), which was implanted into infarcted hearts of immunodeficient mice. Cardiac function was assessed by echocardiography, and cell engraftment was evaluated using immunostaining.

RESULTS

OGPs provided controlled oxygen release for up to 22 days. Inclusion of βCAR minimized OGP-induced oxidative stress, preserved mitochondrial membrane potential, and maintained cell viability. OGP treatment enhanced calcium signaling and contractility in hiPSC-CMs. Transcriptomic analysis revealed that genes associated with CM maturation and contractile function were upregulated following OGP pretreatment. In addition, OGP pretreatment significantly reduced HIF-1α expression, decreased mitochondrial fragmentation, and improved survival. RNA-seq further demonstrated activation of oxygen-responsive metabolic pathways that facilitated cellular adaptation to hypoxic stress. In vivo, OR-EHT implantation for 6 weeks improved cardiac function, increased ejection fraction, reduced ventricular remodeling, and decreased infarct size compared with EHT without OGPs. Moreover, OGP incorporation significantly enhanced engraftment and survival of transplanted hiPSC-CMs and supported features consistent with early structural integration with host myocardium.

CONCLUSION

OGP-mediated oxygen delivery offers a promising strategy for oxidative preconditioning and significantly improves the regenerative efficacy of hiPSC-CM-based cardiac therapies.