Abstract：
In vitro models of the human liver are promising alternatives to animal tests for drug development. Currently, primary human hepatocytes (PHHs) are preferred for pharmacokinetic and cytotoxicity tests. However, they are unable to recapitulate the flow of bile in hepatobiliary clearance owing to the lack of bile ducts, leading to the limitation of bile analysis. To address the issue, a liver organoid culture system that has a functional bile duct network is desired. In this study, we aimed to generate human iPSC-derived hepatobiliary organoids (hHBOs) consisting of hepatocytes and bile ducts. The two-step differentiation process under 2D and semi-3D culture conditions promoted the maturation of hHBOs on culture plates, in which hepatocyte clusters were covered with monolayered biliary tubes. We demonstrated that the hHBOs reproduced the flow of bile containing a fluorescent bile acid analog or medicinal drugs from hepatocytes into bile ducts via bile canaliculi. Furthermore, the hHBOs exhibited pathophysiological responses to troglitazone, such as cholestasis and cytotoxicity. Because the hHBOs can recapitulate the function of bile ducts in hepatobiliary clearance, they are suitable as a liver disease model and would be a novel in vitro platform system for pharmaceutical research use.
摘要：
人类肝脏的体外模型是用于药物开发的动物测试的有希望的替代方案。目前,原代人肝细胞(PHHs)优选用于药代动力学和细胞毒性测试。然而,由于缺乏胆管，他们无法概括肝胆清除中的胆汁流量，导致胆汁分析的局限性。为了解决这个问题，需要具有功能性胆管网络的肝类器官培养系统。在这项研究中,我们旨在生成由肝细胞和胆管组成的人类iPSC来源的肝胆器官（hHBO）。2D和半3D培养条件下的两步分化过程促进了hHBO在培养板上的成熟，其中肝细胞簇被单层胆管覆盖。我们证明了hHBO复制了含有荧光胆汁酸类似物或药物的胆汁通过胆小管从肝细胞流入胆管。此外，hHBO对曲格列酮表现出病理生理反应，如胆汁淤积和细胞毒性。因为hHBO可以概括胆管在肝胆清除中的功能，它们适合作为肝病模型，并且将是用于药物研究的新型体外平台系统。
