Fig. 7
Perfusable cardiac constructs in infarcted rat heart model 5 days post-implantation a, b Immunofluorescent-stained paraffin sections of self-assembled (SA; left) and µV+SA (right) cardiac grafts: a Whole-graft section containing human embryonic stem cell-derived cardiomyocytes (hESC-CMs) (β-MHC, red). Gray dotted line outlines graft tissue. Scale bar, 1 mm. b High magnification images of boxed region in a (yellow box) with hESC-CMs (β-MHC, red, bottom right) and perfused vessels (Lectin+, green, bottom left). Merged, top. Scale bar, 100 μm. c Quantification of cardiomyocyte density (number of β-MHC+ cells per mm2) and β-MHC+ graft size (% LV area). N = 7 and 6 biologically independent animals for SA and µV+SA, with one animal with µV+SA graft excluded from graft size calculation due to partial graft removal during tissue processing. p = 0.015 for density, p > 0.05 for graft size (two-tailed t test). d Quantification of vessel density (number of vessels per mm2) and average vessel size for all perfused vessels (Lectin+) in the cardiac grafts. N = 7 and 6 biologically independent animals for SA and µV+SA, respectively. p = 0.046 for vessel density, p > 0.05 for vessel size (two-tailed t test). e Terminal deoxinucleotidyl transferase-mediated dUTP-fluorescein nick end labeling (TUNEL) assay for apoptotic cells (TUNEL, green) on paraffin sections of SA (left) and µV+SA (right) cardiac grafts. Scale bar, 100 μm. f Quantification of apoptotic cells (TUNEL+) as a percentage of all cells (human and host) in the graft. N = 7 and 6 biologically independent animals for SA and µV+SA, respectively. p > 0.05 (two-tailed t test). Representative images for a, b, e from six biologically independent animals containing SA grafts and five biologically independent animals containing μV+SA grafts, with similar results. Hoechst-stained nuclei, blue. Data were collected from at least two confocal images of randomly selected regions per sample. Images analyzed by a custom lumen identifying code for vessel density and size. Error bars, mean ± SEM. *p < 0.05 determined using two-tailed t test. β-MHC beta-myosin heavy chain
