A Hypoxia-reoxygenation Injury Model in Self-assembling Human Cardioids.

Without rapid revascularization, ischemic heart disease leads to irreversible loss of cardiomyocytes, scar formation, and decreased cardiac function. The ability to model hypoxia-reoxygenation injuries and evaluate potential therapeutic interventions in human tissues is an unmet need. Human cardiac organoids (hCOs) are an emerging model system, but beginning work with hCOs can be challenging due to their small size, requirements for suspension culture, and variability in differentiation efficiency. This protocol offers a user-friendly guide for generating and maintaining human iPSC-derived self-assembling hCOs; methods to process and histologically analyze hCOs; and an approach to injure hCOs with hypoxia-reoxygenation that mimics the fibrosis and apoptosis seen with human ischemia/reperfusion. This protocol provides guidance for using hCOs as a complement to animal models of ischemia-reperfusion injury and could be used to identify and test factors that may boost human myocardial recovery.