The ALTERNATIVE cardiac in vitro system: role of the biomechanical structure and cell composition in the modulation of toxicity response

Three-dimensional (3D) culture systems have been developed to restore in vivo conditions mimicking multicellular micro-tissues. It has been repeatedly demonstrated that only 3D technologies using co-cultures are able to reproduce key aspects of the phenotypical and cellular heterogeneity as well as microenvironmental aspects of tumor growth. This work aims to compare a 3D co-culture of Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes (hiPSC-CMs, 80%) and Human Coronary Artery Endothelial Cells (HCAECs, 20%) versus the gold-standard cell system of 2D hiPSC-CMs (100%), placed in contact with Doxorubicin. The 3D model was established by culturing cells into photo-crosslinked gelatin methacryloyl networks. Gel viscoelastic properties were thoroughly studied by rheology. A dose-response curve (0.001-20?M) was performed, and cells were treated for 7 days. The cell functions (mitochondrial activity, oxidative stress, apoptosis, cell integrity, cardiac and specific cell markers) were characterized. Our results highlighted the increased resistance of the 3D system to Doxorubicin toxic effect with respect to the 2D culture and showed how mitochondrial activity and oxidative metabolism seem to be the most sensible networks to chemical toxicity. The integration of biomechanical and cell stimuli could favor a more precise evaluation of the toxicity profile of chemicals, supporting a reliable transferability of information from the bench to the bedside.