Clonogenic colony-forming ability of hepatic stem cells in the spleens of mice

To confirm the existence of hepatic stem cells (HSCs), fetal liver cells isolated from mice on embryonic day 13 (ED13) were long-term cultured in vitro. Growth of the cells was observed intensively and characteristics were identified by immunocytochemistry. The results showed that some of the cells grew as colonies, in which some cells expressed AFP, CD34 and Albumin. Then the cells were transplanted intravenously into irradiated syngeneic mice. At day 12 a number of small hyperplasia nodules were seen in the apparently enlarged spleens of recipient mice. Moreover, some nodules were positive for AFP and CD34 and consisted of various types of cells, suggesting the very existence of hepatic stem cells in the mouse fetal liver.