Semiautomatic macroencapsulation of fresh or cryopreserved porcine hepatocytes maintain their ability for treatment of acute liver failure

We have previously demonstrated that fresh or cryopreserved xenogeneic hepa tocytes manually macroencapsulated in AN69 polymer and transplanted intrape ritoneally in rats were able to improve the survival rate after 95% hepatec tomy without immunosuppression. In addition, we developed a semiautomatic d evice where porcine hepatocytes were coextruded with AN69 hydrogel in order to macroencapsulate large amounts of cells. The purpose of the present stu dy was to 1) test whether transplanted porcine hepatocytes macroencapsulate d in this device remained functional as evaluated by their ability to preve nt death from acute liver failure, and 2) compare the efficiency of cryopre served or freshly isolated hepatocytes. Fresh or cryopreserved porcine hepa tocytes were macroencapsulated in the semiautomatic device by coextrusion i n AN69 polymer in 2-m minitubes containing 6 x 10(7) cells. Acute liver fai lure was induced in rats by two-step 95% hepatectomy. At the time of comple tion of liver resection, rats were either not transplanted with minitubes ( control group I, n = 13), or were implanted with two minitubes containing c ulture medium (control group II, it = 11), hepatocytes killed by heat treat ment (control group III, n = 10), coextruded fresh hepatocytes (group IV, n = 11), or coextruded cryopreserved hepatocytes (group V, n = 11), without immuno suppression. The survival rate at day 7 was between 0% and 31% in th e three control groups. By contrast, coextruded fresh hepatocytes significa ntly improved the survival rate (group IV, 82%) as did cryopreserved cells (group V, 91% survival). In surviving rats, minitubes were explanted after 20 days: either fresh or cryopreserved hepatocytes appeared morphologically viable and their ultrastructure was preserved. Their detoxification capaci ties evaluated by the activity of the cyt P450 CYP3A4 were partly maintaine d. In conclusion, porcine hepatocytes macro encapsulated by coextrusion usi ng a semiautomatic device and transplanted without immunosuppression were a ble to prevent death from acute liver failure in rats. Cryopreserved cells were as efficient as fresh hepatocytes.