HMOX1 and myocardial infarction: This observation goes in line with those of Luo et al., who demonstrated that pretreatment of hESC-CMs with cobalt protoporphyrin IX (CoPPIX), a potent inducer of HO-1 expression, resulted in significantly larger graft size upon intramyocardial administration in the rat model of acute myocardial infarction in comparison to PBS-pretreated cells [30].