Figure 14.

ETA‐b regresses the HCM pathological phenotype. A, Time course of drug stimulation protocols for beating single cardiomyocytes. The single cardiomyocytes derived from each of the HCM iPSCs, which were dissociated from EBs at 60 days, were cultured for 7 days with or without ET‐1, and then subsequently cultured for 7 days with or without ETA‐b. Immunostainings for cTnT with DAPI nuclear staining were performed at 14 days. B, The isolated cardiomyocytes at 60 days were cultured for 7 days with or without ET‐1 and subsequently cultured for 7 days with or without ET‐1, or ETA‐b. C, Cell surface areas of total 300 randomly chosen cTnT‐positive cardiomyocytes were measured in each culture condition (1‐way ANOVA with Steel's multiple‐comparison post‐test). D, The percentages of cardiomyocytes with myofibrillar disarray were assessed by immunostaining for cTnT of the single cardiomyocytes. N=317 to 361 (per each culture condition). *P<0.001 (χ² test). cTnT indicates cardiac troponin‐T; EBs, embryoid bodies; ET‐1, endothelin‐1; ETA‐b, endothelin receptor type A blocker; HCM, hypertrophic cardiomyopathy; iPSCs, induced pluripotent stem cells.