Michael Didié, Peter Christalla, Michael Rubart, Vijayakumar Muppala, Stephan Döker, Bernhard Unsöld, Ali El-Armouche, Thomas Rau, Thomas Eschenhagen, Alexander P. Schwoerer, Heimo Ehmke, Udo Schumacher, Sigrid Fuchs, Claudia Lange, Alexander Becker, Wen Tao, John A. Scherschel, Mark H. Soonpaa, Tao Yang, Qiong Lin, Martin Zenke, Dong-Wook Han, Hans R. Schöler, Cornelia Rudolph, Doris Steinemann, Brigitte Schlegelberger, Steve Kattman, Alec Witty, Gordon Keller, Loren J. Field, Wolfram-Hubertus Zimmermann
Retention and functional integration of PCMs after intramyocardial injection.
(A and B) Immunofluorescent labeling of α-actinin (red, A) and connexin43 (red, B) in adult ventricular mouse heart tissue 3 weeks after injection of PCMs (EGFP, green; nuclei, blue). (C–F) Two-photon laser scanning microscopy of intracellular Ca2+ transients in adult mouse hearts after injection of PCMs: 2D-scan (C) and line-scan (D) images of stimulated (3 Hz) and spontaneous Ca2+ transients. Arrow 1, EGFP-positive cell; arrow 2, EGFP-negative cell; the dotted line indicates the location of the line scan. Bands of increased rhod-2 fluorescence intensity reflect AP-induced Ca2+ transients. (E) Plots of rhod-2 and GFP line-scan data in the EGFP-expressing cardiomyocyte 1 and the GFP-negative (native) cardiomyocyte 2 as a function of time. (F) Superimposed tracings of AP-evoked changes in rhod-2 fluorescence as a function of time from cardiomyocytes 1 (green) and 2 (red). For each cell, the relative changes in fluorescence were normalized such that 0 represents the prestimulus fluorescence intensity (F0), and 1 represents the peak fluorescence intensity. Additional immunofluorescence analyses confirmed the maturity of engrafted PCMs: A3 line; EGFP-positive; (G) α-actinin (red); (H) actin (red); (I) troponin (red); nuclei (blue; DAPI). Scale bars: (A) 100 μm, (B, C, G–I) 20 μm.