[Rich hematopoietic stem/progenitor cells in the human placenta tissue and placenta blood]

Clinical transplantation evidence has indication that umbilical cord blood (UCB) can be useful in the hematopoietic reconstitution in the children, but not well in the adult patients because of the low cell count. The purpose of our study was to evaluate a new method for collection of blood cells from human placenta and umbilical cord. We have simultaneously harvested blood cells from umbilical cord (UCB), placenta blood (UPB) and placenta tissue (UPT) for their content of nucleated cells, CD34 (hematopoietic stem progenitor marker) positive cells. Result showed that the nuclear cell (NC) from UPB and UPT has three to four times than that from umbilical cord blood only, (8.3 +/- 1.04) x 10(8) (UCB), (16.33 +/- 5.54) x 10(8) (UPB), and (8.01 +/- 2.64) x 10(8) (UPT). CD34(+) cells are (0.77 +/- 0.01) x 10(6), (1.25 +/- 0.55) x 10(6) and (4.21 +/- 1.90) x 10(6) respectively. The cells from UPB and UPT have more survival ability than the cells from UCB in the long-term cell culture condition. It is clear that the blood stored in the liquid nitrogen did not show large loss of total nucleated cell count and CD34(+) cells. It was observed that UPT and UPB contained more suppressor lymphocytes, which may be important in prevention of graft-versus-host disease. In conclusion, our data may have implications for the development of placental blood collection together with umbilical cord blood banking for the stem cell transplantation.