In vitro cardiotoxicity assessment of environmental chemicals using an organotypic human induced pluripotent stem cell-derived model

Abstract

An important target area for addressing data gaps through in vitro screening is the detection of potential cardiotoxicants. Despite the fact that current conservative estimates relate at least 23% of all cardiovascular disease cases to environmental exposures, the identities of the causative agents remain largely uncharacterized. Here, we evaluate the feasibility of a combinatorial in vitro/in silico screening approach for functional and mechanistic cardiotoxicity profiling of environmental hazards using a library of 69 representative environmental chemicals and drugs. Human induced pluripotent stem cell-derived cardiomyocytes were exposed in concentration-response for 30 min or 24 hrs and effects on cardiomyocyte beating and cellular and mitochondrial toxicity were assessed by kinetic measurements of intracellular Ca2+ flux and high-content imaging using the nuclear dye Hoechst 33342, the cell viability marker Calcein AM, and the mitochondrial depolarization probe JC-10. More than half of tested chemicals exhibited effects on cardiomyocyte rhythm after 30 min of exposure. After 24 hours, the effects on cell rhythm without cytotoxicity were observed in about one third of the compounds. Concentration-response data for in vitro bioactivity phenotypes were visualized using Toxicological Prioritization Index (ToxPi) and showed chemical class-specific clustering of environmental chemicals, including pesticides, flame retardants, and polycyclic aromatic hydrocarbons. For environmental chemicals with human exposure predictions, the activity-to-exposure ratios between modeled blood concentrations and in vitro bioactivity were between one and five orders of magnitude. These findings not only demonstrate that some ubiquitous environmental pollutants might have the potential to alter cardiomyocyte function at high exposures, but also indicate similarities in the mechanism of these effects both within and among chemicals and classes.

A human population-based organotypic in vitro model for cardiotoxicity screening

“…In cardiomyocytes derived from the standard commercial iCell cardiomyocyte product offered by Cellular Dynamics International (individual 1434), the results for our selected reference compounds are in excellent agreement with previous reports (Grimm et al, 2015; Sirenko et al, 2013a,b, 2017). Population-level differences in drug response are evident and the degree of inter-individual variability in responses differ depending on chemical and endpoint.…”

“…The Ca 2+ flux assay was used to evaluate functional performance of cardiomyocytes (Grimm et al, 2015; Grimm et al, 2016; Sirenko et al, 2013a, 2013b, 2017). The assay was initiated by addition of 25 μl pre-warmed Ca 2+ dye reagent to cardiomyocytes in a total volume of 25 μl maintenance medium.…”

“…These cells are now used widely for predictive assessment of cardiac arrhythmic potential of drugs and environmental chemicals (Sirenko et al, 2017; Blinova et al, 2017; Pfeiffer et al, 2016); however, no previous study of iPSC-derived cardiomyocytes addressed population inter-individual variability. In this study, the goals were to demonstrate the utility of a human in vitro model for the drug and chemical safety endpoint that currently relies heavily on the use of animals (e.g., dogs) and to bridge clinical and experimental paradigms by a model that can be used to address population-based cardiovascular safety.…”

Polyaromatic hydrocarbons in pollution: a heart‐breaking matter

“…; Sirenko et al . ) but have only very recently been utilized for PAH toxicity testing. High‐throughput in vitro cardiotoxicity of a library of 69 representative environmental chemicals and drugs was successfully assessed using hiPSC‐derived cardiomyocytes (Sirenko et al .…”

Stem cells in toxicological research

“…Research efforts have focused particularly on stem cell-derived cardiomyocyte and hepatocyte like cells and on developmental toxicity as well as developmental neurotoxicity (Waldmann et al 2017;Shinde et al 2015Shinde et al , 2016Meganathan et al 2015). Standardized protocols are available that allow the generation of beating cardiomyocytes derived from embryonic or induced pluripotent stem cells (Sirenko et al 2017). This offers the possibility to study whether test compounds compromise rhythmic beating patterns of the cells (Chaudhari et al 2017).…”