Development of a hybrid artificial liver using a polyurethane foam/ hepatocyte-spheroid packed-bed module

Primary dog hepatocytes spontaneously formed spheroids in the pores of polyurethane foam (PUF) within 1-2 days of stationary culture. The spheroids, about 100-150 μm in diameter, partly attached to the surface and immobilized inside these pores. The lidocaine disappearance rate decreased to about 4 μg/10⁵ viable cells/day for 10 days, while in the PUF/spheroid culture the rate was maintained at almost the initial level of 8 μg/10⁵ viable cells/day for 10 days. Then, two scales of PUF packed-bed modules were designed. A small module (PUF volume; 14.5 cm³) was used for in vitro culture to investigate optimum culture conditions, and a large module (PUF volume; 300 cm³) was designed for dog experiments. Hepatocytes inoculated in these modules also formed spheroids and maintained almost the same activity of albumin secretion rate (111 μg/cm³ PUF/day in the small module and 87.7 μg/cm³ PUF/day in the large module). These results indicate that the PUF packed-bed module containing hepatocyte-spheroids is promising as a hybrid artificial liver.