Effect of intrasplenic transplantation of immortalized human hepatocytes in the treatment of acetaminophen-induced acute liver failure SCID mice

Objective. We have established immortalized human hepatocytes by transduction of HPV16 E6/E7 and hTERT (HHE60T-1). The cells retained the characteristics of differentiated hepatocytes, but the functional characteristics such as albumin secretion, ureogenesis, and glyconeogenesis decreased gradually as the passages progressed beyond 200 population doublings (PDs). In this report, we transplanted minimally differentiated HHE6E7T-1 cells into the spleens of acute liver failure severe combined immunodeficiency (SCID) mice to examine the potential of the cells to redifferentiate in vivo. Materials and Methods. Acute liver failure was induced in SCID mice by intraperitoneal injection of 400 mg/kg acetaminophen. Two hours later, HHE6E7T-1 cells at 200 PDs were transplanted: group 1 (n = 10) 50 mu L phosphate-buffered saline (PBS); group 2 (n = 9), lysate of 1 x 10(6) HHE6E7T-1 cells at 200 PDs resuspended in 50 mu L PBS; and group.3 (n = 8), 1 X 106 HHE6E7T-1. cells. Survival rates at 7 days after transplantation were compared. Blood glucose levels, plasma ammonia levels, and spleen histology were examined at 24 hours after transplantation. Results. Survivals in each group were: 30% for group 1, 33% for group 2, and 100% for group 3. The survival of group 3 was significantly higher than groups 1 or 2 (P < .01). Plasma ammonia levels in group 3 (200 +/- 34 mu g/dL) were significantly lower than those in group 1 (325 (+/-) 92 mu g/dL; P < .05). Blood glucose levels in group 3 (110 +/- 20 mg/dL) were significantly higher than those in group 1 (83 +/- 14 mg/dL; P < .05). Upon histologic examination of spleen, the clusters of HHE6E7T-1 cells were clearly identified. Conclusions. The immortalized human hepatocytes, HHE6E7T-1 at 200 PDs, improved the survival of acute liver failure mice through possible redifferentiation in vivo.