RESUMEN
BACKGROUND AIMS: With the continuous development and advancement of human pluripotent stem cell (PSC)-derived cell therapies, an ever-increasing number of clinical indications can benefit from their application. Due to the capacity for PSCs to form teratomas, safety testing is required to ensure the absence of residual PSCs in a cell product. To mitigate these limitations, in vitro analytical methods can be utilized as quality control after the production of a PSC-derived cell product. Sensitivity of these analytic methods is critical in accurately quantifying residual PSC in the final cell product. In this study, we compared the sensitivity of three in vitro assays: qPCR, ddPCR and RT-LAMP. METHODS: The spike-in samples were produced from three independent experiments, each spiked with different PSC lines (PSC1, NH50191, and WA09 referred to as H9) into a background of primary fibroblasts (Hs68). These samples were then subjected to qPCR, ddPCR and RT-LAMP to determine their detection limit in measuring a commonly used PSC marker, LIN28A. RESULTS: The results indicated that the three analytic methods all exhibited consistent results across different cell-line spiked samples, with ddPCR demonstrating the highest sensitivity of the three methods. The LIN28A ddPCR assay could confidently detect 10 residual PSCs in a million fibroblasts. DISCUSSION: In our hand, ddPCR LIN28A assay demonstrated the highest sensitivity for detection of residual PSCs compared to the other two assays. Correlating such in vitro safety results with corresponding in vivo studies demonstrating the tumorigenicity profile of PSC-derived cell therapy could accelerate the safe clinical translation of cell therapy.
RESUMEN
Preclinical data have confirmed that human pluripotent stem cell-derived cardiomyocytes (PSC-CMs) can remuscularize the injured or diseased heart, with several clinical trials now in planning or recruitment stages. However, because ventricular arrhythmias represent a complication following engraftment of intramyocardially injected PSC-CMs, it is necessary to provide treatment strategies to control or prevent engraftment arrhythmias (EAs). Here, we show in a porcine model of myocardial infarction and PSC-CM transplantation that EAs are mechanistically linked to cellular heterogeneity in the input PSC-CM and resultant graft. Specifically, we identify atrial and pacemaker-like cardiomyocytes as culprit arrhythmogenic subpopulations. Two unique surface marker signatures, signal regulatory protein α (SIRPA)+CD90-CD200+ and SIRPA+CD90-CD200-, identify arrhythmogenic and non-arrhythmogenic cardiomyocytes, respectively. Our data suggest that modifications to current PSC-CM-production and/or PSC-CM-selection protocols could potentially prevent EAs. We further show that pharmacologic and interventional anti-arrhythmic strategies can control and potentially abolish these arrhythmias.