Liver‐Specific Gene Expression in Cultured Human Hematopoietic Stem Cells

Hematopoietic and hepatic stem cells share characteristic markers such as CD34, c‐kit, and Thy1. Based on the recent observations that hepatocytes may originate from bone marrow, we investigated the potential of CD34+ bone marrow cells to differentiate into hepatocytic cells in vitro. CD34+ and CD34− human bone marrow cells were separated by magnetic cell sorting. Cells were cultured on a collagen matrix in a defined medium containing hepatocyte growth factor. Cell count and size were measured by flow cytometry, and reverse transcription polymerase chain reaction was carried out for the liver‐specific markers CK‐19 and albumin. During cell culture, CD34+ cells showed an increasing cell number and proliferative activity as assessed by Ki‐67 staining. Under the specified culture conditions, CD34+ cells expressed albumin RNA and CK‐19 RNA after 28 days, whereas CD34− cells did not show liver‐specific gene expression. The results indicate that CD34+ adult human bone marrow stem cells can differentiate into hepatocytic cells in vitro.