ABSTRACT
OBJECTIVE: Tissue-specific stem cells from differentiating embryonic stem (ES) cells are both pluripotent and genetically flexible. Recent observations indicate that ES cells can differentiate into hepatocytes. Therefore, cell-based therapy can potentially be a therapeutic alternative to liver transplantation. In this study the treatment of acute liver failure in rats by transplantation of hepatocyte nuclear factor 4 (HNF4)-overexpressing ES cells was investigated. METHODS: The HNF4 was transfected into ES cells and ES cell clones overexpressing HNF4 were selected. The levels of markers of hepatocyte differentiation, including albumin, transthyretin, glucose-6-phosphates (G-6-P) and SAPK/ERK kinase-1 (SEK1) mRNA, were tested in spontaneously differentiated HNF4-overexpressing ES cells by reverse transcription-polymerase chain reaction (RT-PCR). The ultrastructure of the spontaneously differentiated HNF4-overexpressing ES cells was examined by electron microscopy. To induce acute liver failure, Sprague-Dawley rats were subjected to 90% hepatectomy and given 5% oral dextrose. The rats were divided into three groups. The rats in the treatment group (n = 12) received intraliver injection of 2 x 10(7) undifferentiated HNF4-overexpressing ES cells from the same clone, the rats in control group 1 (n = 12) received 2 x 10(7) undifferentiated ES cells, and the rats in control group 2 (n = 12) received the same volume of media without any cells. RESULTS: All rats in control group 1 and control group 2 died within 72 h, while 33% of rats that received undifferentiated HNF4-overexpressing ES cells transplantation survived more than 1 month. Spontaneously differentiated HNF4-overexpressing ES cells only expressed transthyretin mRNA. The cells were rich in mitochondrion and catalase-containing peroxisomes in ultrastructure. CONCLUSIONS: Transplantation of ES cells could be a potential treatment in supporting life during acute liver insufficiency and could be a bridge to orthotopic liver transplantation.
