Cyclophosphamide arrhythmogenicitytesting using human-induced pluripotent stem cell-derived cardiomyocytes

Abstract

Cyclophosphamide (CP) is an anticancer drug, an alkylating agent. Cardiotoxicity of CP is associated with one of its metabolites, acrolein, and clinical cardiotoxicity manifestations are described for cases of taking CP in high doses. Nevertheless, modern arrhythmogenicity prediction assays in vitro include evaluation of beat rhythm and rate as well as suppression of cardiac late markers after acute exposure to CP, but not its metabolites. The mechanism of CP side effects when taken at low doses (i.e., < 100 mg/kg), especially at the cellular level, remains unclear. In this study conduction properties and cytoskeleton structure of human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) obtained from a healthy donor under CP were evaluated. Arrhythmogenicity testing including characterization of 3 values: conduction velocity, maximum capture rate (MCR) measurements and number of occasions of re-entry on a standard linear obstacle was conducted and revealed MCR decrease of 25% ± 7% under CP. Also, conductivity area reduced by 34 ± 15%. No effect of CP on voltage-gated ion channels was found. Conduction changes (MCR and conductivity area decrease) are caused by exposure time-dependent alpha-actinin disruption detected both in hiPSC-CMs and neonatal ventricular cardiomyocytes in vitro. Deviation from the external stimulus frequency and appearance of non-conductive areas in cardiac tissue under CP is potentially arrhythmogenic and could develop arrhythmic effects in vivo.

Polymer Kernels as Compact Carriers for Suspended Cardiomyocytes

“…In this study, we used an m34Sk3-induced pluripotent stem cell line reprogrammed from a healthy (without hereditary cardiovascular diseases) donor [ 22 ]. The direct cardiac differentiation (ventricular-like iPSC-CMs) was performed in 24-well plates (covered with Matrigel) according to the modification of the Gi-Wi protocol [ 23 , 24 ]. Immunocytochemistry, optical mapping and flow cytometry have confirmed stable differentiation efficiency for the m34Sk3 cell line (50% of ventricular-like cardiac cells in population from 20 to 86th day of differentiation) [ 14 , 22 , 23 , 24 ].…”

“…The direct cardiac differentiation (ventricular-like iPSC-CMs) was performed in 24-well plates (covered with Matrigel) according to the modification of the Gi-Wi protocol [ 23 , 24 ]. Immunocytochemistry, optical mapping and flow cytometry have confirmed stable differentiation efficiency for the m34Sk3 cell line (50% of ventricular-like cardiac cells in population from 20 to 86th day of differentiation) [ 14 , 22 , 23 , 24 ]. The preparation of neonatal rat ventricular myocytes (NRVMs) samples was performed according to the Worthington protocol [ 19 ] ( ).…”

Effect of strain‐dependent conduction slowing on the re‐entry formation and maintenance in cardiac muscle: 2D computer simulation

“…These results show that a decrease in myocardial excitability combined with increased stimulation frequency can cause wave detachment from a nonexcitable obstacle in our electromechanical model in agreement with experimental observations. 23,24 The effect of MEF (i.e., the dependence of the CV on myocardium strain) on the wave detachment and re-entry formation was tested at an increased excitability threshold (a ¼ 0:15) and the stimulation frequency of 2 Hz. The snapshots of the wave propagation with and without MEF are shown in Figure 4.…”

Reverse cardio-oncology: A budding concept

“…Alkylating agents like Cyclophosphamide have shown to cause heart failure and conduction blocks. 32 Apart from causing oxidative stress it also causes nitrative stress due to its metabolic byproduct acrolein. 33 These lead to degeneration and vacuolisation of myocardial cells.…”