Organoid technology provides a revolutionary paradigm toward therapy but has yet to be applied in humans, mainly because of reproducibility and scalability challenges. Here, we overcome these limitations by evolving a scalable organ bud production platform entirely from human induced pluripotent stem cells (iPSC). By conducting massive "reverse" screen experiments, we identified three progenitor populations that can effectively generate liver buds in a highly reproducible manner: hepatic endoderm, endothelium, and septum mesenchyme. Furthermore, we achieved human scalability by developing an omni-well-array culture platform for mass producing homogeneous and miniaturized liver buds on a clinically relevant large scale (>10). Vascularized and functional liver tissues generated entirely from iPSCs significantly improved subsequent hepatic functionalization potentiated by stage-matched developmental progenitor interactions, enabling functional rescue against acute liver failure via transplantation. Overall, our study provides a stringent manufacturing platform for multicellular organoid supply, thus facilitating clinical and pharmaceutical applications especially for the treatment of liver diseases through multi-industrial collaborations.

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Microdosing studies are effective in enabling the early identification of the pharmacokinetic properties of compounds administered to humans. However, the nonlinearity of the pharmacokinetics between microdose and therapeutic dose, attributable to the saturation of metabolic enzymes and transporters, is a major concern. Verapamil and quinidine are good substrates of both the multidrug resistance 1 transporter (MDR1) and the cytochrome P450 (CYP) 3A4 enzyme (CYP3A4). We investigated their dose-dependent pharmacokinetics in healthy subjects. Four different doses of verapamil or quinidine were administered orally to each subject, and the plasma concentrations of the parent drugs and their major metabolites were measured. The dose-normalized area under the plasma concentration-time curve (AUC) values of quinidine and verapamil increased in a dose-dependent manner and were 2.6- and 2.3-fold higher, respectively, at the therapeutic dose than at microdose. These results suggest that the nonlinear pharmacokinetics of these drugs is caused mainly by the saturation of MDR1 and/or CYP3A4 in the small intestine.

Three new pyrrolopyrimidine alkaloids, rigidins B-D (1-3), have been isolated from an Okinawan marine tunicate Cystodytes sp., and the structures were elucidated on the basis of spectroscopic data.

A study of the pharmacokinetics of (14)C-labeled acetaminophen (AAP) was performed in healthy Japanese subjects receiving an oral microdose of the drug. After separation by high-performance liquid chromatography (HPLC), the levels of AAP and its metabolites in the pooled plasma specimens were quantified using accelerator mass spectrometry (AMS). The total body clearance (CL(tot))/bioavailability (F) of AAP was within the variation in the reported values at therapeutic doses, indicating the linearity of AAP pharmacokinetics. AAP-glucuronide (Glu) and AAP-4-O-sulfate satisfied the criteria of safety testing of drug metabolites. AMS could detect AAP-Cys, the active metabolite of AAP conjugated with cysteine, in the urine. Probenecid prolonged the systemic elimination of total radioactivity and caused a marked decrease in AAP-Glu levels in plasma. Probenecid likely inhibited the glucuronidation of AAP and the renal elimination of AAP-4-O-sulfate. Microdosing of (14)C-labeled drug followed by AMS is a powerful tool that can be used in the early phase of drug development for pharmacokinetic analysis of drugs and their metabolites and for detecting the formation of active metabolites in humans.

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