Liver-Chips and Liver Spheroids as Models to Determine Hepatic Safety and Metabolism
Abstract: Drug-induced liver injury continues to be a major focus in candidate selection and clinical development in consideration of therapeutic index. Accordingly more predictive and translational model systems are required to assess human hepatotoxicity risk. Organs-on-Chip technology recreate dynamic microenvironments (flow) and represent promising models to assess mechanistic hepatotoxicity, due to enhanced liver phenotype, metabolic activity and stability in culture not attainable with conventional 2D models. Increased sensitivity of these models to drug-induced hepatotoxicity has been demonstrated vs 2D static cultures. However, a comprehensive evaluation of liver spheroid co-cultures and microengineered Organ-Chip models has not been undertaken. Here we report on evaluation of primary human hepatocyte spheroids and the Liver-Chip using two hepatotoxins with different mechanisms of hepatotoxicity, acetaminophen (APAP) and fialuridine (FIAU).
We assessed the sensitivity of the models across a range of cytotoxicity biomarkers (ATP, albumin (ALB), αGST, miR-122) and their metabolic functionality by incorporating quantitation of APAP and FIAU metabolites. Comparisons were made at equivalent time points and dose and were expressed as EC50, absolute or % control. Dose dependent increases in αGST and miR-122, as well as decreases in ALB, were observed in both the Liver-Chip and the hepatic spheroid model. APAP metabolite formation was maintained until day 10 and dose dependent increases were observed in both models at times/doses where no cytotoxicity was detected. For FIAU, the most sensitive endpoints were ALB in the Liver-Chip and miR-122 in the spheroids respectively, both on day 7.
Overall, both models demonstrated integrated toxicity and metabolism with released toxicity biomarkers observed earlier in the Liver-Chip.