Responsiveness of the widely used cardiomyocyte cell platforms to simulated ischemia/reperfusion

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): National Research, Development and Innovation Office of Hungary (NKFIA; NVKP-16-1-2016-0017 National Heart Program and OTKA-FK 134751) MTA-SE System Pharmacology Research Group, Department of Pharmacology and Pharmacotherapy, Semmelweis University, H-1089 Budapest, Hungary Ischemic heart disease is the leading cause of death worldwide; therefore, the development of cardioprotective therapies is currently a main focus of research. Cultured cell lines and primary cell cultures play an integral role in cardiovascular research. However, there are many limitations when using these models, including variations in proliferation capacity, uncontrolled stress during cell isolation, poor reproducibility and low translational value. The aim of our study was to test the responsiveness of the most widely used cardiomyocyte platforms to simulated ischemia/reperfusion injury (SI/R) considering the effect of differentiation protocols. Human, rat and mouse cell lines as well as primary cell cultures were used for in vitro viability assay with or without widely used differentiation protocols. The cells were exposed to normoxic or simulated ischemia/reperfusion protocols: a simulated ischemic period of 6 hours was used for the primary and the differentiated cell cultures, while for the non-differentiated cells 16 hours of simulated ischemia followed by 2 hours of reperfusion was applied. The duration of simulated ischemia was determined from preliminary experiments. Viability of the cells was measured by calcein assay. In non-differentiated human AC16 and rat H9C2 cardiac cell lines, cell viability was significantly reduced (50%) by 16h SI / 2h R in contrast, the viability of the mouse HL-1 cell line was not reduced by 16 h SI. In primary rat neonatal cardiac myocytes 6h SI / 2h R caused significant cell death (25%). In primary human iPSC-derived cardiac myocytes 6h SI / 2h R did not result significant injury (10%) whereas 16h did (37%). Responsiveness of different cell types to SI/R ranged between 40-100%. We have shown that the responsiveness of primary cardiac cells and non-differentiated cardiac cell lines is significantly different to simulated ischemia / reperfusion. Differentiation protocols in cell lines markedly affects their response to simulated ischemia / reperfusion. Comparative analyses of different types of cardiomyocytes can provide a goo