FIG. 5.

In vivo differentiation capacity of heart-implanted hASCs and FP-ASCs. hASCs and FP-ASCs were doubly labeled with either Troponin-1 or PECAM-1 inducible promoter–regulated PLuc-EGFP, and constitutive CMV promoter–regulated RLuc-RFP constructs and seeded in a fibrin patch. The fibrin matrix was then implanted over the ventricular area of myocardium infarct model in mice and imaged by BLI regularly. The ratio of PLuc to RLuc photons (PLuc/RLuc), recorded in the BLI images, was used to evaluate the changes in inducible promoter activity. (A) The histogram represents the change in PLuc/RLuc ratio relative to implantation day (week 0) for each cell type and reporter, n=4. (B) Heart excised after the BLI experiment showing epifluorescent and bioluminescent signals from stem cells seeded in the fibrin patch. (C) Fluorescence confocal microscope images of myocardial sections 3 weeks p.i. showing from left to right: RFP constitutively expressed in all the implanted hASCs and FP-ASCs; EGFP expressed in hASCs and FP-ASCs that differentiated to either the endothelial lineage (PECAM-1 promoter, top panel) or to the cardiomyocytic lineage (Troponin-I promoter, bottom panel); protein antigens, Troponin-I and PECAM-1, detected using the corresponding anti-Troponin-I and anti-PECAM-1 antibodies, shown in gray (top and bottom panels, respectively); overlay of the previous images plus Hoechst staining of nuclei. In each panel, the top row shows FP-ASCs while the bottom row shows hASCs. PLuc, Photinus pyralis luciferase; RLuc, Renilla reniformis luciferase. Color images available online at www.liebertpub.com/scd