SummaryDespite the enormous replication potential of the human liver, there are currently no culture systems available that sustain hepatocyte replication and/or function in vitro. We have shown previously that single mouse Lgr5+ liver stem cells can be expanded as epithelial organoids in vitro and can be differentiated into functional hepatocytes in vitro and in vivo. We now describe conditions allowing long-term expansion of adult bile duct-derived bipotent progenitor cells from human liver. The expanded cells are highly stable at the chromosome and structural level, while single base changes occur at very low rates. The cells can readily be converted into functional hepatocytes in vitro and upon transplantation in vivo. Organoids from α1-antitrypsin deficiency and Alagille syndrome patients mirror the in vivo pathology. Clonal long-term expansion of primary adult liver stem cells opens up experimental avenues for disease modeling, toxicology studies, regenerative medicine, and gene therapy.

PWA is a simple and reproducible technique with which to measure PWV and AIx. Reproducibility accords with that reported by other workers using different methodologies. PWA may, therefore, be suitable for large-scale population and intervention studies investigating the clinical relevance of vascular stiffness.

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Background and Aims The gap between patients on transplant waiting lists and available donor organs is steadily increasing. Human organoids derived from leucine‐rich repeat‐containing G protein‐coupled receptor 5 (LGR5)–positive adult stem cells represent an exciting new cell source for liver regeneration; however, culturing large numbers of organoids with current protocols is tedious and the level of hepatic differentiation is limited. Approach and Results Here, we established a method for the expansion of large quantities of human liver organoids in spinner flasks. Due to improved oxygenation in the spinner flasks, organoids rapidly proliferated and reached an average 40‐fold cell expansion after 2 weeks, compared with 6‐fold expansion in static cultures. The organoids repopulated decellularized liver discs and formed liver‐like tissue. After differentiation in spinner flasks, mature hepatocyte markers were highly up‐regulated compared with static organoid cultures, and cytochrome p450 activity reached levels equivalent to hepatocytes. Conclusions We established a highly efficient method for culturing large numbers of LGR5‐positive stem cells in the form of organoids, which paves the way for the application of organoids for tissue engineering and liver transplantation.