Hepatocytes are being studied for a wide variety of applications, including drug metabolism studies, gene therapy, and use in liver-assist devices for temporary liver support. The ability to cryopreserve isolated hepatocytes would permit the pooling of cells to reach the required therapeutic coordination of the cell supply with patient care regimes and the completion of safety and quality-control testing. The objective of this investigation was to develop a method of cryopreserving isolated hepatocytes that will retain high levels of function and facilitate the use of the cells in different applications. Freshly isolated hepatocytes were cultured in a spinner flask for different periods of time, up to 48 h. The cells were cryopreserved by use of a range of solution concentrations and cooling rates. For fresh, nonfrozen hepatocytes precultured for 24 h prior to being plated on collagen, the albumin secretion rate was 0.88 ± 0.62 mg/ml/h. When the cells were precultured for 24 h, frozen in a solution containing 10% Me2SO with a cooling rate of 1°C/min, thawed, plated on collagen, and cultured, the albumin secretion rate was 0.21 ± 0.24 μg/ml/h. In contrast, freshly isolated hepatocytes cryopreserved without preculture and cultured on collagen had an albumin secretion rate of 0.07 ± 0.08 mg/ml/h. The influences of different solution compositions and cooling rates on postthaw function of precultured hepatocytes were also determined. These results indicate that the use of a preliminary culture step prior to cryopreservation can enhance the postthaw function of hepatocytes.
- in vitro culture