In vitro evaluation of metabolic functions of a bioartificial liver

The purpose of this study is to develop a bioartificial liver (BAL) with such a simple structure that it can be prepared within several hours and through which whole blood can be perfused as in current hemodialyzers. Hepatocytes were isolated from 37 pigs; each liver weighed 300 to 400 g. The average yield of hepatocytes was 2.4 +/- 0.6 x 10(10) cells per liver, with a cell viability of 89.6 +/- 3.9%. To prepare a BAL device, a cartridge, composed of hollow fibers made of cellulose diacetate was used. Nominal cut-off molecular weight of the hollow fibers was 68 kDa, and the internal diameter was 195 microm. One hundred milliliters of hepatocyte suspension, containing 1 x 10(10) cells, was inoculated into the inner space of the hollow fibers, and both the inlet and outlet of the hollow fiber cartridge were closed. It took only 3 hrs from administration of the pig's anesthesia to the start of an in vitro evaluation of the prepared BAL device. To evaluate the functions of this BAL quantitatively, using a pharmacokinetic method, a mixture of fresh human blood and Dulbecco's modified Eagle medium was circulated in the shell space of the hollow fibers at 200 ml/min. Chemicals (lidocaine, ammonia, and galactose) were then loaded into the perfusion medium. The average intrinsic clearance of the BAL device was found to be 46 ml/min for lidocaine and 8.8 ml/min for ammonia. The galactose elimination capacity of the BAL device was 1.34 mg/min. The metabolic function of the BAL device decreased by 81%, 49%, and 64% of the initial function for lidocaine, ammonia, and galactose, respectively, after 10 days of in vitro circulation.