There is a need for long‐lived hepatic in vitro models to better predict drug induced liver injury (DILI). Human liver‐derived epithelial organoids are a promising cell source for advanced in vitro models. Here, organoid technology is combined with biofabrication techniques, which holds great potential for the design of in vitro models with complex and customizable architectures. Here, porous constructs with human hepatocyte‐like cells derived from organoids are generated using extrusion‐based printing technology. Cell viability of bioprinted organoids remains stable for up to ten days (88–107% cell viability compared to the day of printing). The expression of hepatic markers, transporters, and phase I enzymes increased compared to undifferentiated controls, and is comparable to non‐printed controls. Exposure to acetaminophen, a well‐known hepatotoxic compound, decreases cell viability of bioprinted liver organoids to 21–51% (p < 0.05) compared to the start of exposure, and elevated levels of damage marker miR‐122 are observed in the culture medium, indicating the potential use of the bioprinted constructs for toxicity testing. In conclusion, human liver‐derived epithelial organoids can be combined with a biofabrication approach, thereby paving the way to create perfusable, complex constructs which can be used as toxicology‐ and disease‐models.

Emerging advances in the field of in vitro toxicity testing attempt to meet the need for reliable human-based safety assessment in drug development. Intrahepatic cholangiocyte organoids (ICOs) are described as a donor-derived in vitro model for disease modelling and regenerative medicine. Here, we explored the potential of hepatocyte-like ICOs (HL-ICOs) in in vitro toxicity testing by exploring the expression and activity of genes involved in drug metabolism, a key determinant in drug-induced toxicity, and the exposure of HL-ICOs to well-known hepatotoxicants. The current state of drug metabolism in HL-ICOs showed levels comparable to those of PHHs and HepaRGs for CYP3A4; however, other enzymes, such as CYP2B6 and CYP2D6, were expressed at lower levels. Additionally, EC50 values were determined in HL-ICOs for acetaminophen (24.0–26.8 mM), diclofenac (475.5–>500 µM), perhexiline (9.7–>31.5 µM), troglitazone (23.1–90.8 µM), and valproic acid (>10 mM). Exposure to the hepatotoxicants showed EC50s in HL-ICOs comparable to those in PHHs and HepaRGs; however, for acetaminophen exposure, HL-ICOs were less sensitive. Further elucidation of enzyme and transporter activity in drug metabolism in HL-ICOs and exposure to a more extensive compound set are needed to accurately define the potential of HL-ICOs in in vitro toxicity testing.

Liver-on-a-chip models predictive for both metabolism, and blood and canalicular transport of drug candidates in humans are lacking. Here, we established a bioengineered and 3Rs-complied (animal component-free) hepatocyte-like millifluidic system based on 3D hollow fiber membranes (HFMs), recombinant human laminin 332 coating and adult human stem cell-derived organoids. Organoid fragments formed polarized and tight monolayers on HFMs with improved hepatocyte-like maturation, as compared to standard 3D organoid cultures in Matrigel from matched donors. Gene expression profiling and immunofluorescence revealed that hepatocyte-like monolayers expressed a broad panel of phase I (e.g. CYP3A4, CYP2D6, CYP2C9) and II (e.g. UGTs, SULTs) drug-metabolizing enzymes and drug transporters (e.g. MDR1, MRP3, OATP1B3). Moreover, statically cultured monolayers displayed phase I and II metabolism of a cocktail of six relevant compounds, including midazolam and 7-hydroxycoumarin. We also demonstrated the disposition of midazolam in the basal/blood-like circulation and apical/canalicular-like compartment of the millifluidic chip. Finally, we studied the bioavailability of midazolam and coumarin on-a-chip in combination with a small intestine-like system. In conclusion, we generated a proof-of-concept liver organoid-on-a-chip model for examining metabolism and transport of drugs, which can be further developed to predict pharmacokinetics’ (PK)/absorption, distribution, metabolism and excretion (ADME) profiles in humans.

There is a concern on the safety of cosmetic ingredients and their endocrine-disrupting (ED) potential. Frequent use as well as the use of a diverse range of cosmetics pose a concern for a potential health risk via aggregate exposure to endocrine disrupting chemicals (EDCs). In this study, a list of ingredients available in cosmetic products that were recently introduced to the Dutch market was retrieved from the commercially accessible Mintel database and screened for the presence of EDCs. To achieve this, a workflow was developed to crosscheck the list of cosmetic ingredients with information on potential EDCs derived from open-source initiatives (i.e. chemical lists from the European Chemicals Agency, national authorities, and non-governmental organizations). Using this workflow, 27 chemicals were identified that were categorized as "indications for ED properties" and one chemical as "no concern for ED properties" out of the 890 cosmetic ingredients reviewed. For one of these chemicals, geraniol, a preliminary safety assessment was performed. Aggregated exposure to geraniol via cosmetics was modeled using PACEMweb and compared to the lowest observed adverse effect level on thyroid histopathology derived from an extended-one-generation study. This exercise showed that, based on the current information available, geraniol can be used safely in cosmetics with regard to endocrine-related health risks. Next, the cosmetic ingredients that are currently not identified as an EDC (i.e. not present on one of the crosschecked lists, n = 862), were prioritized based on an aggregate exposure score for further screening of their endocrine disrupting properties (n = 58). For eight out of the 58 prioritized chemicals data retrieved from a literature search indicated an endocrine-mediated relationship, and were categorized as "limited indications of ED properties". Overall, the developed workflow is a useful tool to screen cosmetics for the presence of potential EDCs and to prioritize chemicals for further evaluation of their ED properties, as well as assessment of their safe use in cosmetics.