Placental/umbilical cord blood-derived mesenchymal stem cell-like stromal cells support hematopoietic recovery of X-irradiated human CD34+ cells.
OBJECTIVE
The potential of human mesenchymal stem cell-like stroma prepared from placental/umbilical cord blood for hematopoietic regeneration by X-irradiated hematopoietic stem cells is herein assessed.


METHODS
Placental/umbilical cord blood-derived mesenchymal stem cell-like stromal cells were applied to a regenerative ex vivo expansion of X-irradiated human CD34(+) cells in a serum-free liquid culture supplemented with a combination of interleukine-3 plus stem cell factor plus thrombopoietin.


RESULTS
The total number of cells and of lineage-committed myeloid hematopoietic progenitor cells generated in the co-culture of both non-irradiated and X-irradiated cells with stromal cells was significantly higher than those in the stroma-free culture. In addition, the number of CD34(+) cells and CD34(+)/CD38(-) cells, immature hematopoietic stem/progenitor cells also increased more than the stroma-free culture. The stromal cells produced various types of cytokines, although there was little difference between the co-cultures of non-irradiated and X-irradiated cells with stromal cells. Furthermore, when X-irradiated cells came in contact with stromal cells for 16 h before cytokine stimulation, a similar degree of hematopoiesis was observed, thus suggesting the critical role of cell-to-cell interaction.


CONCLUSIONS
The present results showed the potential efficacy of human mesenchymal stem cell-like stroma for hematopoietic regeneration from irradiated hematopoietic stem/progenitor cells.
Hayashi
Naoki
N
Department of Radiological Life Sciences, Hirosaki University Graduate School of Health Sciences, 66-1 Hon-cho, Hirosaki, Aomori 036-8564, Japan.
Takahashi
Kenji
K
Abe
Yoshinao
Y
Kashiwakura
Ikuo
I
D018952:Antigens, CD34 / Q000276:immunology*; D017209:Apoptosis; D005260:Female; D005312:Fetal Blood / Q000166:cytology*; D006801:Humans; D008214:Lymphocytes / Q000166:cytology / Q000276:immunology / Q000528:radiation effects*; D059630:Mesenchymal Stem Cells / Q000166:cytology*; D010920:Placenta / Q000166:cytology*
D018952:Antigens, CD34