Z Gastroenterol 2008; 46 - P3_19
DOI: 10.1055/s-2008-1037590

A highly enriched fetal liver stem/progenitor cell population containing all the repopulation potential for the normal adult rat liver

M Oertel 1, A Menthena 1, YQ Chen 1, B Teisner 2, C Harken Jensen 2, DA Shafritz 1
  • 1Marion Bessin Liver Research Center, Albert Einstein College of Medicine, Bronx, USA
  • 2University of Southern Denmark, Odense C, Denmark

Stem cell transplantation is a promising alternative to whole liver transplantation. However, identification and characterization of true liver stem cells has been problematic, because there are no known specific markers. Previously, we reported long-term liver replacement of normal adult rat liver after transplanting unfractionated embryonic day (ED)14 fetal liver stem/progenitor cells (FLSPC). However, hematopoietic stem cells, a major component in unfractionated fetal liver cell preparations, engraft in other organs and may cause undesirable side effects or complications. Therefore, for most clinical applications, highly purified cell fractions will be needed.

Dlk–1, a cell surface transmembrane protein, is highly expressed in rodent and human fetal liver and “oval“ (progenitor) cells in the adult liver. We purified ED14 FLSPC to 95% homogeneity for Dlk–1 using MACS. In contrast to Dlk–1- cells, Dlk–1+ cells are AFP+/CK19+ or AFP+/CK–19- and exhibit all cell culture and gene expression characteristics expected for hepatic stem/progenitor cells.

After transplantation of up to 1.9×106 Dlk–1+ cells (equivalent to 32×106 unfractionated cells) into the normal liver in conjunction with 2/3 partial hepatectomy, these cells engrafted, proliferated, and differentiated into hepatocytes and bile ducts, expressing unique hepatocyte- or cholangiocyte-specific proteins (e.g., albumin, G6P, ASGPR, UGT1A1, CK–19, OV–6, connexin 43). The level of liver repopulation exceeded 15% at 6 months after transplantation of Dlk–1 purified FLSPC. Since hematopoietic stem cells were totally removed by Dlk–1 selection, Dlk–1+ FLSPC repopulate only the liver. In contrast, Dlk–1- cells did not repopulate the normal liver, however, they engraft in other organs.

This is the first study to purify highly enriched hepatic stem/progenitor cells from fetal liver that exhibit all of the normal liver repopulation potential found in the fetal liver. This represents a significant advance toward developing protocols that will be essential for clinical application of liver cell transplantation technology.