title: Direct differentiation of hepatic cells from human induced pluripotent stem cells using a limited number of cytokines.
abstract: OBJECTIVE
  Development of improved protocols for differentiating induced pluripotent stem (iPS) cells into hepatic cells is an important step toward their use in the field of hepatology. Specifically, the number of different cytokines should be reduced to limit undesired effects and to reduce the cost of the process. In this report, we describe a simple method for directing human iPS cells to differentiate into hepatic cells using only two cytokines and a short incubation time.
  
  
  METHODS
  A two-step protocol for differentiating iPS cells into hepatic cells was developed. A high dose of activin A was applied for 3 days to induce definitive endoderm formation. Subsequently, cells were treated with hepatocyte growth factor (HGF) for 5 days to generate hepatic cells. Differentiation was confirmed by immunostaining for differentiation markers. Albumin mRNA levels in differentiated hepatic cells generated using a previously tested three-step protocol that uses activin A, fibroblast growth factor (FGF)/bone morphogenetic protein (BMP), and HGF, and our new protocol were compared to determine the efficiency of differentiation.
  
  
  RESULTS
  Our two-step protocol induced the differentiation of iPS cells into hepatic cells and required a shorter differentiation period than the previous three-step protocol. The differentiation efficiencies of the two protocols were comparable and the induced hepatic cells were functional.
  
  
  CONCLUSIONS
  Developing efficient induction and culture methods to generate more highly matured hepatocytes is essential for regenerative cell-based therapies. Our protocol provides a simple, cost-effective, and time-saving approach for generating hepatic cells from iPS cells.
authors.affiliation: Department of Gastroenterology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.
authors.forename: Akemi
authors.initials: A
authors.lastname: Takata
authors.affiliation: Department of Gastroenterology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan. otsukamo-tky@umin.ac.jp.
authors.forename: Motoyuki
authors.initials: M
authors.lastname: Otsuka
authors.affiliation: Department of Medicine and Institute of Gastroenterology, Tokyo Women's Medical University, Tokyo, Japan.
authors.forename: Tomomi
authors.initials: T
authors.lastname: Kogiso
authors.affiliation: Department of Gastroenterology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.
authors.forename: Kentaro
authors.initials: K
authors.lastname: Kojima
authors.affiliation: Department of Gastroenterology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Yoshikawa
authors.affiliation: Department of Gastroenterology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.
authors.forename: Ryosuke
authors.initials: R
authors.lastname: Tateishi
authors.affiliation: Global COE Program, Centre for Education and Research for the Advanced Genome-Based Medicine, Unit of Disease Control Genome Medicine, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan.
authors.forename: Naoya
authors.initials: N
authors.lastname: Kato
authors.affiliation: Department of Gastroenterology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.
authors.forename: Shuichiro
authors.initials: S
authors.lastname: Shiina
authors.affiliation: Department of Gastroenterology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.
authors.forename: Haruhiko
authors.initials: H
authors.lastname: Yoshida
authors.affiliation: Department of Gastroenterology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.
authors.forename: Masao
authors.initials: M
authors.lastname: Omata
authors.affiliation: Department of Gastroenterology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Koike