[Sustainment of hepatocyte function with mixed cellular co-encapsulation]

To evaluate the effects of mixed microcapsules of hepatocytes mixed with hepatocytes, transgenic hepatic stellate cell strain (HGF/CFSC), and/or bone marrow derived Thy-1(+) beta(2)M(-) cells (BDTCs) to sustain liver function.

Three kinds of microcapsules containing hepatocytes, hepatocytes + CFSC/HGFs, or hepatocyte + CFSC/HGF + BDTC were prepared and cultured in conditioned culture fluids. The morphology of the microcapsules and the encapsulated cells were observed by microscopy. The supernatant was collected regularly to detect the secretion of albumin and urea. Forty Wistar rats underwent 90% hepatectomization to establish acute liver failure model. Six hours after the operation the rats were randomly divided into 4 groups to be intraperitoneally injected with one of the 3 kinds of microcapsules containing 3.5 x 10(7) hepatocytes as experimental groups (Groups II, III, and IV) or injected with blank microcapsule as control group. The behaviors of the rats were observed daily. Blood was collected from the eyeball at different time points to detect relevant biochemical indicators. Twenty-one and 42 days after the operation the rats were killed. Abdominal lavage was performed to collect the microcapsules to undergo microscopy. Liver specimens were colleted to undergo pathological examination.

Severe liver failure occurred in the rats transplanted with blank microcapsules. Most of the rats in Groups II, III, and IV began to eat within 20 hours after hepatectomization. Nine of the 10 rats in the control group died within 48 hours after hepatectomization. Nine of the 10 rats of Group II survived a long time. All the rats in Groups III and IV survived till the end of experiment. In comparison with the supernatant of Group II, the contents of albumin and urea in the supernatants of Groups III and IV were significantly higher (all P < 0.01). The liver function indicators, ALT, AST, lactic dehydrogenase, and albumin worsened since one day after the operation. Five days after the transplantation of microcapsule, the above indicators showed remarkable improvement, and recovered to normal 7 days after. Twenty-one and 42 days after the transplantation regeneration was seen and edema was reduced in the livers in Groups II, III, and IV. Twenty-one days after the transplantation most of the microcapsules were still free in the peritoneal cavity in Group II. In Group III, most of the microcapsules aggregated around the portal vein, fibrosis at the surface of microcapsule to a certain degree was seen and surviving hepatocytes could be found inside the capsules 21 days after. Forty-two days after, vascularization of microcapsules was seen in Groups III and IV, especially in the latter group.

Mature hepatocyte, transgenic liver nonparenchymal cells and/or BMSCs co-encapsulate transplantation effectively improve acute liver failure. The microenvironment created by CFSC/HGF and/or BDTC is propitious to the maintenance of capsulated hepatocytes' function and longevity.