Hepatocyte Transplantation: Cell Sheet Technology for Liver Cell Transplantation

Abstract

Purpose of review: We will review the recent developments of cell sheet technology as a feasible tissue engineering approach. Specifically, we will focus on the technological advancement for engineering functional liver tissue using cell sheet technology, and the associated therapeutic effect of cell sheets for liver diseases, highlighting hemophilia.

Recent findings: Cell-based therapies using hepatocytes have recently been explored as a new therapeutic modality for patients with many forms of liver disease. We have developed a cell sheet technology, which allows cells to be harvested in a monolithic layer format. We have succeeded in fabricating functional liver tissues in mice by stacking the cell sheets composed of primary hepatocytes. As a curative measure for hemophilia, we have also succeeded in treating hemophilia mice by transplanting of cells sheets composed of genetically modified autologous cells.

Summary: Tissue engineering using cell sheet technology provides the opportunity to create new therapeutic options for patients with various types of liver diseases.

Keywords: Cell sheet; Hemophilia; Hepatocyte; Liver disease; Transplantation.

Fig. 1

Schematic illustrations of cell sheet engineering using temperature-responsive cell culture dishes. Temperature-responsive polymer poly(N-isopropylacrylamide) (PIPAAm) is covalently grafted on the cell culture plastic dishes at nanometer thickness. This PIPAAm coating provides a slightly hydrophobic surface at the regular culture temperature (37 °C), allowing conventional cell culturing. The lower critical solution temperature of PIPAAm is 32 °C, indicating PIPAAm shows hydrophobic characteristics over 32 °C, whereas it changes to hydrophilic state below 32 °C. Therefore, the PIPAAm coating allows conventional cell culturing at the regular culture temperature (37 °C), but the cultured cells cannot adhere to the surface below 32 °C because of rapid hydration and swelling of the grafted PIPAAm. This results in the spontaneous detachment of the cultured cells from the dishes as a viable monolayer cell sheet format. The PIPAAm remains on the dish surface during the cell detachment process, and the cell sheet maintains the extracellular matrix (ECM) including adhesive protein on their basal side