One day blood donation may become a thing of the past. Scientists at the RIKEN BioResource Center in Tsukuba, Japan are developing stem cell techniques that could lead to growing red blood cells in vitro, possibly making blood donation obsolete.
The research team, led by Yukio Nakamura, initially induced hematopoiesis—that is, differentiation from the stem cell into more mature blood and immune system cells—in mouse embryonic stem cells by culturing the stem cells on a layer of so-called feeder cells in the presence of specific growth factors as well as the synthetic steroid drug dexamethasone.
The team reports they established a total of five cell lines by this method. Three cell lines exhibited characteristics of erythroid, or red blood cells. The other two lines exhibited the characteristics of mast cells, a type of immune system cell.
Analysis of the three erythroid cell lines demonstrated that the cells expressed genes specific for erythroid cells. Furthermore, the cells expressed α and β globin chains, which are only expressed by adult erythroid cells. By altering the growth conditions, the team could induce cells to further differentiate in vitro into more mature erythroid cells, including red blood cells (Fig. 1).
Next, the researchers examined the ability of the erythroid cell lines to produce RBCs in vivo in mice suffering from acute anemia. The injection of the erythroid cell lines ameliorated the anemia, suggesting that differentiation of the injected cells occurred in vivo to produce RBCs similar to those produced naturally by the host mouse.
The researchers also evaluated the potential for the cell lines to form tumors in vivo as some stem cell lines have been associated with tumorigenicity. Mature RBCs lack a nucleus, and hence lack DNA, so carry little risk of tumorigenesis, but the less mature cells produced by the cell line do contain DNA. After transplanting the cell lines into mice, no tumors were observed for six months, suggesting that these cell lines were not tumorigenic.
Press release: Transfusable blood from a stem cell …
Image caption: The erythroid cell line could be induced to further differentiate, generating mature red blood cells lacking nuclei (marked by arrows).