Fig. 5

Histological analysis of injured hearts with GCaMP3+ hESC-CM grafts. a Representative cryoinjured heart with GCaMP3+ ESI-17 hESC-CM graft immunostained for beta myosin heavy chain (β-MHC) (muscle, red) and human-specific Ku80 nuclear protein (graft nuclei, brown) and counterstained with aniline blue (scar tissue, blue). Graft tissue within the box is shown at higher magnification to the right. b Graft size by histomorphometry, expressed as the percentage of injury area occupied by graft. n = 3–5 hearts per condition. c Confocal photomicrograph of cryoinjured heart with GCaMP3+ H7 hESC-CM graft near the border zone, immmunostained for GCaMP3+ (anti-GFP antibody, green) and β-myosin heavy chain (β-MHC, red). d Adjacent histological section stained with Masson’s trichrome stain. e Confocal photomicrograph of GCaMP3+ H7 hESC-CM graft near border zone immunostained for GCaMP3+ (anti-GFP antibody, green) and Cx43 (red). While grafts consistently exhibited a lower level of Cx43 expression than host myocardium, occasional scattered Cx43 gap junction plaques were observed (white arrowheads). f Adjacent histological section immunostained for GCaMP3+ and N-cadherin (red). Qualitatively similar patterns of Cx43 and N-cadherin expression were observed by grafts formed by ESI-17 and RUES2 hESC-CMs, as well as grafts with or without GCaMP expression (data not shown)