Abstract 14419: Modeling Catecholaminergic Polymorphic Ventricular Tachycardia Using Human Induced Pluripotent Stem Cells: A Promising Tool for Drug Discovery
Background: Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an inherited disorder characterized by adrenergically mediated ventricular tachyarrhythmias which cause syncope and sudden death without structural heart diseases.
Methods: We obtained dermal fibroblasts from a 43-year-old female with a diagnosis of familial CPVT due to a missense mutation in the RyR2 gene, p.I4587V and successfully generated induced pluripotent stem (iPS) cells using a combination of 4 transcription factors (Oct3/4, Sox2, Klf-4, c-Myc) by retrovirus systems. Cardiomyocyte differentiation of the iPS cells was induced with embroid body (EB) differentiation system. Beating EBs (2-3 months after differentiation was initiated) were dispersed into single cells. They were loaded with Fluo-8 and Ca2+ imaging was conducted. The cells were electrically stimulated by field stimulation.
Results: Without isoproterenol, we found significantly frequent diastolic Ca2+ waves in CPVT cardiomyocytes (35%, n=37) than control (differentiated from 201B7 iPS cells, 13%, n=39) with stimulation at 0.5 Hz (p<0.05), however, the percentage of cells with diastolic Ca2+ waves were not significantly different in control (11%, n=44) and CPVT cardiomyocytes (18%, n=39) when stimulated at 1 Hz. After 100 nM isoproterenol application, diastolic Ca2+ waves occurred significantly more frequently in CPVT than control with both 0.5 Hz (CPVT: 55%, n=31 vs. control: 22%, n=36, p<0.05) and 1 Hz (CPVT: 50%, n=34 vs. control: 19%, n=43, p<0.05) electrical stimulation. Ryanodine 10 μM completely eliminated diastolic Ca2+ waves in all CPVT cells studied (n=12).
Conclusions: We generated disease-specific iPS cells from a CPVT patient. The differentiated cardiomyocytes had an increased susceptibility to catecholamine induced diastolic calcium waves and ryanodine suppressed them. It is suggested that this iPS cell-based model of CPVT is useful for investigating new pharmacotherapies.
- © 2013 by American Heart Association, Inc.