Methods: Human embryonic stem cells (hESCs HES2, NSCB, Madison, USA) and human induced pluripotent stem cells (hiPSCs ADHF#1, iCEMS, Kyoto University, Japan) were expanded and differentiated on matrigel-coated micro-channels for 20 days. Hepatocyte-like cells were characterized with hepatic markers and functional tests. Both differentiated cells and HepG2 control cells were treated with different

concentrations of acetaminophen dissolved in Selleck Obeticholic Acid dimethyl sulfoxide and hepatic medium. Hepatotoxicity was assessed by cell morphology and albumin secretion changes, nuclear dimensions, alanine transaminase (ALT) assay and cell mortality, measured with calcein AM and ethidium homodimer-1. Results: Hepatocyte-like cells showed a high, indocyanine uptake, glycogen storage and albumin secretion, and a higher CYP3A expression in microfluidic compared to static (p<0.01). HepG2 cells were treated with increasing CDK inhibitor acetaminophen concentrations (ctrl, 1, 5, 10, 25, 50 mM), both in static and microfluidic condition. Microfluidic

cultured cells showed a significantly inverse (p<0.05) correlation of drug concentration with nuclear area decrease, from 150 to 50 um2. Hepatocyte-like cells responded to 24h microfluidic acetaminophen treatments with loss of cell morphology and albumin expression. Live and dead assay failed to show any difference in cell mortality of HepG2 cell cultured either in static and microfluidic conditions. A significant (p<0.01) difference was noticed between microfluidic hepatocyte-like cells vs static differentiated cells. Microfluidic cells correlated in cytotoxicity with increasing acetaminophen concentrations (up to 73±4% cell death with 25 mM drug, after 24h treatment), while static cells did not respond to drug toxicity. Microfluidic platform allowed performing dose and posology-dependent experiments. 4 drug administrations (of 3h Casein kinase 1 each) during the 24h gave a significantly higher (p<0.01) cytotoxic effect (20±4% cell

death with 25 mM drug) compared to lower administrations, regardless to the higher overall amount of drug in a single-administration. Conclusions: The engineerization of hPSC differentiation into hepatic lineages will allow to further understanding the mechanisms involved in tissue development. Moreover, mature hepatic cells fully integrated on a chip can be directly used for temporal-defined toxicological assays. Disclosures: The following people have nothing to disclose: Giovanni G. Giobbe, Federica Michielin, Alessandro Zambon, Stefano Giulitti, Camilla Luni, Nicola Elvassore, Annarosa Floreani Tumor necrosis factor-inducible gene 6 protein (TSG-6), one of cytokines released by mesenchymal stem/stromal cells (MSC), was known to have the anti-inflammatory effect and alleviate several pathological conditions, but its hepatoprotective potential remains unclear.