Extended Data Figure 4. Enhanced maturation and synchronicity of cardiac tissues in response to training regimen as a function of time.
Representative contraction profiles of a fetal cardiac tissues (FCT), b early-stage and c late-stage cardiac tissues (C2A cell line) over time. d Frequency of contractions in cardiac tissues over 4 weeks of culture (n = 35 biologically independent samples over 16 independent experiments) Mean ± 95% CI, *p<0.05 compared to control group by two-way ANOVA with Tukey’s HSD test. Early-stage intensity training is significant against other training regimens by two-way ANOVA with Tukey’s HSD test. e Characterization of cardiac cell population within cardiac tissues (C2A line) after 4 weeks of culture by FACS analysis. Characterization of cells isolated from early-stage intensity trained cardiac tissues (C2A line) by FACS analysis after 4 weeks of culture for f cardiac cells (cardiac troponin T, cTnT) and g supporting fibroblast cells (vimentin) and endothelial cells (von Willebrand Factor, vWF). h–j Representative immunofluorescent images obtained from whole tissues via confocal microscopy detailing the enhanced cardiac ultrastructure: a-actinin (green), cardiac troponin T (red), nuclei (blue) within early-stage cardiac tissues from the h C2A line, i WTC11 cell line, and j, IMR90 cell line after 4 weeks of culture (scale bar = 5 μm, experiment repeated independently 14 times with similar results). k Representative immunofluorescent images detailing the cell population: cardiac troponin T (cTnT, green), vimentin (red), nuclei (blue) within a histological section from early-stage cardiac tissue (C2A line) after 4 weeks of culture (scale bar = 50 μm, experiment repeated independently 2 times with similar results).