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. Author manuscript; available in PMC: 2021 Jul 3.
Published in final edited form as: Circ Res. 2020 Mar 31;127(2):207–224. doi: 10.1161/CIRCRESAHA.119.316155

Figure 7. Mechanical function of hChaMPs.

Figure 7.

a) Contractility in terms of beats per minute of cardiomyocytes of hChaMPs at 2 and 6 weeks following differentiation and lactate purification. At right, contractility in terms of rates of contraction and relaxation of cardiomyocytes of hChaMPs at 2 and 6 weeks following differentiation and lactate purification. n = 4 hChaMPs at week 2 and n = 3 hChaMPs at week 6, n.s. = not statistically significant; for beat rate, P = 0.324, Student’s T-Test; for contraction rate, P = 0.235, Student’s T-Test; for relaxation rate, P = 0.229, Mann-Whitney U Test. b) A representative map of contractility rate from an hChaMP with spontaneous activity. c) Dose-response effect of isoproterenol in hChaMPs, measured by contractility in terms of beat rate, from at least 3 different areas across 2 hChaMPs. d) An overview of the methodology for obtaining interchamber pressure and volume using a pressure transducer coupled to a conductance catheter for obtaining estimates of distance from the catheter to the chamber wall and back-calculating chamber volume. Catheters were threaded through one of the large vessels extending from the top of the hChaMP and placed submerged in a 37°C bath containing culture medium that was mounted on a temperature-controlled heated stage. Catheter readouts were amplified to provide real time measurement of pressure and volume. Fast Fourier transform was used to convert pressure vs. time associations to beat rates. e) Representative traces of pressure and volume dynamics over a 2.5 second interval in hChaMPs with and without isoproterenol as well as in acellular control hChaMPs were used for generating corresponding pressure-volume loops (3 contraction cycles for each condition). f) Isoproterenol response in terms of beat rate measured by catheters, n = 4 hChaMPs per condition. *P < 0.05, ****P < 0.001, One-way ANOVA with Tukey’s Post Hoc Test. g) Ejection fraction of spontaneously contracting hChaMPs (Spon, n = 7 hChaMPs), hChaMPs treated with 1 μM isoproterenol (1 μM Iso, n = 4 hChaMPs), and acellular control hChaMPs (Ctrl, n = 3 hChaMPs). *P < 0.05, **P < 0.01, One-way ANOVA with Tukey’s Post Hoc Test.