Three-dimensional perfusion cultures of mouse and pig fetal liver cells in a packed-bed reactor: Effect of medium flow rate on cell numbers and hepatic functions

To develop a tissue-engineered bioartificial liver (BAL), perfusion cultures of mouse and pig fetal liver cells (FLCs) immobilized within a three-dimensional (3D) porous scaffold were performed utilizing a packed-bed reactor system. These FLCs were cultured under different medium flow rate conditions, and the effects of the flow rates on cell growth and the hepatic functions of the FLCs were investigated. In the cultures of mouse FLCs, the medium flow suppressed cell growth and the albumin secretion activity of the FLCs, and considerably lower albumin secretion than that in the 3D stationary control cultures was obtained in the perfusion cultures. In the case of pig FLCs, cell growth was also inhibited by the medium flow, however, the cells exhibited higher tolerance to the medium flow compared with mouse FLCs. The albumin secretion activity of pig FLCs was well maintained under an extremely low flow rate condition (4.8 mm/min in the reactor), and activity higher than the 3D stationary cultures was detected at a later stage (after 20 days in the perfusion cultures). These results revealed that FLCs are quite sensitive to medium flow and an extremely low shear stress is required for the perfusion cultures of FLCs.