Fig. 4. Bioluminescence detection of transplanted iPS-CMs. Luciferase-expressing cardiomyocytes were transplanted under low-dose MSC/iPS-CM condition. Mice were analyzed for luciferase activity over 28 days and luminescence was quantitatively recorded (A). The red line indicates the relative bioluminescence of cells transplanted into hearts following cryo-lesion, while the blue line illustrates the bioluminescence of cells injected into healthy recipients. Luminescence signals were defined as 100% (starting value) at day one after transplantation for each individual mouse. Relative luciferase signal as compared to the starting value at day one was calculated for each time point (B).