Abstract 2972: Functional Characterization of Human Induced Pluripotent Stem Cell Derived Cardiomyocytes
[Background] Although many genetic cardiac disorders have been identified, their underlying genetic mechanisms are largely unknown. In this regard, human induced pluripotent stem (iPS) cells may provide an adequate supply of customized patient-specific cells for genetic and functional analyses, thereby enhancing the potential for clinical applications. However, human iPS cell-derived cardiomyocytes (hiPS-CMs) have barely been characterized to date. The purpose of this study was to examine the physiological properties of hiPS-CMs.
[Methods and Results] Human iPS cells were generated from adult dermal fibroblasts using Yamanaka 3 and 4 transcription factors. The hiPS-CMs were differentiated using embryoid body (EB) method. Immunohistochemistry revealed the expression of cardiac marker and sarcomeric proteins including Nkx2.5, GATA4, atrial natriuretic peptide, α-actinin, myosin heavy chain, and tropomyosin in hiPS-CMs. Conventional microelectrode recordings demonstrated the spontaneous action potential configuration with nodal-, atrial- and ventricular-like phenotypes. Furthermore, hiPS-CMs were analyzed using multielectrode array. The application of ion channel inhibitors including quinidine, verapamil and E-4031, as well as β-adrenergic stimulant resulted in dose-dependent changes to the field potential waveform. RT-PCR showed that hiPS-CMs expressed the cardiac ion channel genes such as SCN5A, hERG and Cav1.2. Intracellular Ca23 transient was also observed in hiPS-CMs, confirming the establishment of cardiac excitation-contraction coupling. There was no significant difference in physiological properties of hiPS-CMs generated by Yamanaka 3 and 4 factors.
[Conclusions] Our data showed that cardiomyocytes, when differentiated from hiPS cells, have functional characteristics similar to native cardiomyocytes in the response of the anti-arrhythmic agents and the intracellular Ca2+ transient. The structural and functional properties of hiPS-CMs might be independent of the combination of transcription factors for reprogramming. These universal functional properties of hiPS-CMs may make it easier to apply hiPS technology for clinical use.