Aims: Stem cell therapy has shown promise for treating myocardial infarction (MI) via re-muscularization and paracrine signaling in both small and large animals. Non-human primates (NHPs), such as rhesus macaques (Macaca mulatta), are primarily utilized in preclinical trials due to their similarity to humans, both genetically and physiologically. Currently, induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) are delivered into the infarcted myocardium by either direct cell injection or an engineered tissue patch. Although both approaches have advantages in terms of sample preparation, cell-host interaction, and engraftment, how the iPSC-CMs respond to ischemic conditions in the infarcted heart under these two different delivery approaches remain unclear. Here we aim to gain a better understanding of the effects of hypoxia on iPSC-CMs at the transcriptome level.
Methods and results: NHP iPSC-CMs in both monolayer culture (2 D) and engineered heart tissue (EHT) (3 D) format were exposed to hypoxic conditions to serve as surrogates of direct cell injection and tissue implantation in vivo, respectively. Outcomes were compared at the transcriptome level. We found the 3 D EHT model was more sensitive to ischemic conditions and similar to the native in vivo myocardium in terms of cell-extracellular matrix/cell-cell interactions, energy metabolism, and paracrine signaling.
Conclusions: By exposing NHP iPSC-CMs to different culture conditions, transcriptome profiling improves our understanding of the mechanism of ischemic injury.
Translational perspective: Stem cell therapy has shown promise for treating ischemic heart tissue. However, how stem cells respond following different delivery method is unclear. Here hypoxic conditioning was applied to non-human primate iPSC-CMs in 2 D monolayer culture and 3 D engineered heart tissue to model cell injection versus patch implantation, respectively, in an ischemic milieu. The differential transcriptome of hypoxic effects on iPSC-CMs show upregulation of ECM-cell/cell-cell interactions (COL9A1, ITGB6, CTSV, and EPHA1), energy metabolism/hypoxia (ALDOC, ENO2, PFKFB4, CA3, and CA9), and paracrine signaling (WNT, PDGF, FGFR, EGFR, PI3K, and VEGF) in the 3 D format, which suggest engineered heart tissue as more suitable model for evaluating cardiac regenerative therapy.
Keywords: cardiomyocytes; engineered heart tissue; hypoxia; induced pluripotent stem cells; nonhuman primate; transcriptome.