Abstract 13963: Evidence of Content-Dependent Functional and Electrical Coupling of Human Induced Pluripotent Stem Cell-Derived Engineered Cardiac Tissue With Chronic Infarct Rat Myocardium

Background: It has been shown that transplantation of engineered cardiac tissue (ECT) derived from human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) into the infarct heart induces electrical communication between the ECT and the native myocardium; however, factors enhancing the electrical integrity and thus the therapeutic effects are not fully understood. We herein hypothesized that content of cardiomyocytes in the ECT may be a key to achieve efficient electrical coupling and functional contribution in chronic rat myocardial infarction (MI) heart. Methods and Results: Neonatal rat cardiomyocytes (NRCM), mimicking the host myocardium, were partially covered by the ECT containing iPSC-CMs produced by thermoresponsive culture dishes in vitro , to explore electrical communication of the ECT with myocardium. As a result, the NRCM and the ECT showed spontaneous, individual contractions for 2 hours, though they gradually showed electrical and motional synchronization, featuring transmitted electrical pulse from the NRCM to the ECT, as assessed by multi-electrode array. Subsequently, the ECT of different ratios (25, 50, 70, and 90%) of iPSC-CMs were generated by magnetic-activated cell sorting using cardiac specific cell surface marker. As a result, the 70% group exhibited the highest contractile and relaxation properties in vitro , as assessed by high-speed video microscopy image-based motion analysis and Ca transient measurement. Finally, the ECTs including 25, 50, 70% CMs were transplanted to immune deficient rat MI model (n=7 each). As a result, ejection fraction was significantly improved in the 50% (52±10%) and 70% (52±12%) groups, but not in the 25% group (35±5%), as compared to the control (35±10%; P <0.05). Epicardial optical mapping of Langendorff perfused heart on day 3 showed that the ECTs of 50% and the 70% groups exhibited electrical activity and synchronization with the native myocardium. Conclusion: Transplantation of the ECT improved cardiac performance associated with synchronization with the myocardium in rat infarction model, dependent upon content of the cardiomyocytes in the ECT. It was thus suggested that transplanted ECT may behave “working cardiac construct” in the damaged heart.

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Chronic optical pacing conditioning of h-iPSC engineered cardiac tissues

Journal of Tissue Engineering ◽

10.1177/2041731419841748 ◽

2019 ◽

Vol 10 ◽

pp. 204173141984174 ◽

Cited By ~ 6

Author(s):

Marc Dwenger ◽

William J Kowalski ◽

Fei Ye ◽

Fangping Yuan ◽

Joseph P Tinney ◽

...

Keyword(s):

Stem Cell ◽

Electrical Stimulation ◽

Pluripotent Stem Cell ◽

Cardiac Tissue ◽

Induced Pluripotent Stem Cell ◽

Mechanical Stretch ◽

In Vitro Models ◽

Cardiac Tissues ◽

Induced Pluripotent

The immaturity of human induced pluripotent stem cell derived engineered cardiac tissues limits their ability to regenerate damaged myocardium and to serve as robust in vitro models for human disease and drug toxicity studies. Several chronic biomimetic conditioning protocols, including mechanical stretch, perfusion, and/or electrical stimulation promote engineered cardiac tissue maturation but have significant technical limitations. Non-contacting chronic optical stimulation using heterologously expressed channelrhodopsin light-gated ion channels, termed optogenetics, may be an advantageous alternative to chronic invasive electrical stimulation for engineered cardiac tissue conditioning. We designed proof-of-principle experiments to successfully transfect human induced pluripotent stem cell derived engineered cardiac tissues with a desensitization resistant, chimeric channelrhodopsin protein, and then optically paced engineered cardiac tissues to accelerate maturation. We transfected human induced pluripotent stem cell engineered cardiac tissues using an adeno-associated virus packaged chimeric channelrhodopsin and then verified optically paced by whole cell patch clamp. Engineered cardiac tissues were then chronically optically paced above their intrinsic beat rates in vitro from day 7 to 14. Chronically optically paced resulted in improved engineered cardiac tissue electrophysiological properties and subtle changes in the expression of some cardiac relevant genes, though active force generation and histology were unchanged. These results validate the feasibility of a novel chronically optically paced paradigm to explore non-invasive and scalable optically paced–induced engineered cardiac tissue maturation strategies.

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

Scientific Reports ◽

10.1038/s41598-020-79085-5 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

A. D. Podgurskaya ◽

M. M. Slotvitsky ◽

V. A. Tsvelaya ◽

S. R. Frolova ◽

S. G. Romanova ◽

...

Keyword(s):

Stem Cell ◽

Pluripotent Stem Cell ◽

Cardiac Tissue ◽

Capture Rate ◽

Stimulus Frequency ◽

Induced Pluripotent Stem Cell ◽

Cellular Level ◽

Induced Pluripotent

AbstractCyclophosphamide (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.

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