iPS, organoids and 3D models as advanced tools for in vitro toxicology

Recent progress in the field of in vitro toxicology has led to the development of increasingly complex models that are closer to the complexity of organs and tissues, both in terms of structure and functionality, and are characterized by more precise, specif- ic and early endpoints (Ranga et al., 2014; Xinaris et al., 2015; Clevers, 2016; Jackson and Lu, 2016; Bartfeld and Clevers, 2017; Pamies et al., 2018; Truskey, 2018). The transition from traditional 2D models to three-dimensional (3D) systems cer- tainly represents the most important innovation of the last de- cades. Numerous studies now employ 3D systems, spheroids and organoids, also based on pluripotent stem cells, for the study of drug toxicity. However, the still high cost of these systems limits their use in xenobiotic screening and environmental tox- icology (Kolaja, 2014; Gómez-Lechón and Tolosa, 2016; Luz and Tokar, 2018; Lynch et al., 2019).