A step in the right direction in constructing a bioartificial hepatic organ was taken by researchers at the Department of Surgery, Okayama University Graduate School of Medicine And Dentisity, Japan and Harvard-massachusetts Institute of Technology when they managed to establish a human cholangiocytic cell line. The cells would be useful I providing a bile drainage system in the bioartificial hepatic organ in conjunction with hepatocytes.

The researchers had previously established human liver cell lines using simian virus 40 large T antigen (SV40T) gene. The catalytic subunit of human telomerase reverse transcriptase (hTERT) that elongates the length of telomere has been implicated as a crucial participant in the cellular immortalization process. In liver-targeted cell therapies such as a bioartificial liver, the presence of the bile drainage system is of extreme importance. The establishment of human cholangiocytes cell line would allow the provision of a structure for bile excretion and therefore the engineering of a cholangiocytes line using a retroviral vector encoding the genes of hTERT and green fluorescence protein (GFP) as a positive selectable marker was embarked upon.

One of the human liver OUMS-21 cells were retrovirally transuded with the genes of hTERT and GFP. Following retroviral transduction, cells were trypsinized, dissociated into a single-cell were suspension, and subjected to FACS for GFP. Eventually, a single cell clone was obtained by a limiting dilution method. One of resulting clones, OUMS-21/hTERT , was established and used in the present study. Telomerase activity and gene expression of liver marker were also examined. It was found that the OUMS-21hTERT cells showed telomerase activity, whereas parental cell had activity. This data was consistent with the unlimited proliferative property of OUMS-21/hTERT   cells. The cells showed the expression of cytokeratin 7 and 19 as a marker of cholangiocytes by RT-PCR and Western blotting analysis. In contrast, the cells were negative for hepatocytes-specific marker such as albumin, or bilirubin UGT. OUMS-21/ hTERT cells demonstrated well-organized web formation in a Matrigel assay, which suggests cholangiogenetic potential of the cells.