Extended Data Fig. 5: Comparison to conventional cardiac differentiation and long-term culture of HFOs.

a, Selected genes, which were up- or downregulated in HFOs compared to cardiomyocytes generated by a conventional 2D differentiation protocol and respective gene functions according to the GeneCards database³⁸. FC= fold change. b, Cryosections of aggregates generated by a conventional 3D cardiac differentiation protocol stained for the cardiac markers NKX2.5, cTnT and sarcomeric actinin (SA). c, Long-term culture of HFOs. HES3 NKX2.5-eGFP-derived HFOs were cultured up to 146 days in suspension after dissolving the surrounding Matrigel. HFOs were stained with DiI-Ac-LDL to visualize endothelial cells. Scale bars: b: 100 µm; c: 500 µm.