[Study on the ex vivo expansion characteristics of umbilical cord blood CD34+ cells and mononuclear cells].
To explore the ex vivo expansion characteristics of selected CD(34)(+) cells and mononuclear cells (MNC).
CD(34)(+) cells were isolated from umbilical cord blood MNC by MiniMACS system, expanded under the same conditions as that for MNC. The effects of re-isolation and the MNC supernatant (MNC-SN) on the selected CD(34)(+) cells were investigated. And the CD(34)(-) cells of MNC were cultured ex vivo.
In the culture of selected CD(34)(+) cells, both the colony density and the proportion of the CD(34)(+) cells declined continuously with the culturing, although they presented a high proliferation potential. However, in the culture of the MNC, from day 0 to day 7, the colony density and the proportion of CD(34)(+) cells were increased from 412 +/- 167/10(5) cells and (1.12 +/- 0.42)% to 1 162 +/- 566/10(5) cells and (4.17 +/- 1.44)%, respectively. It was found that both the total cells and the CD(34)(+) cells restored expansion potential by re-isolating. CD(34)(-) cells of MNC had the ability to form colony and could transform to CD(34)(+) cells. MNC-SN can promote colony forming ability and lead to CD(34)(+) cells differentiation at the same time.
In ex vivo culture, selected CD(34)(+) cells presented a high proliferation and differentiation potentials, and the CD(34)(-) cells produced during the cultivation had inhibition effect on CD(34)(+) cells expansion. CD(34)(-) cell population from cord blood MNC contained hematopoietic stem/progenitor cells and the cytokines secreted by CD(34)(-) cells could induce CD(34)(+) cells to more mature colony-forming cells.
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ABSTRACT: The CD34(+) cell dose and infused number of committed progenitor cells in transplantation are important factors in hematologic engraftment. However, the relationship between expansion potential of progenitor cells and hematologic engraftment remains controversial. We evaluated whether expansion potential of progenitor cells is a predictive factor of post-transplantation hematologic engraftment.
Mononuclear cells isolated from mobilized peripheral blood and bone marrow were cultured with cytokine cocktail for 7 days. Progenitor cells and committed progenitors were analyzed using stem cell markers (CD34 and CD133) and lineage specific markers. Hematologic engraftment was defined as neutrophil counts over 500/microL and platelet counts over 20,000/microL without transfusion. Acute and chronic graft-versus-host disease (GVHD) were investigated.
There was inverse tendency between the number and fold expansion of progenitor cells or committed (granulocytic or megakaryocytic) progenitors and time to engraftment. Especially, fold expansion of CD34(+)/CD33(+) cells was significantly correlated with time to neutrophil engraftment in bone marrow transplantation (r=-0.56, P=0.04). The infused number and fold expansion of lymphoid progenitors were not related to the occurrence of acute or chronic GVHD.
We could not prove that expansion potential of progenitor cells and committed progenitor cells is correlated to hematologic engraftment although there is a correlation between CD34(+)/ CD33(+) cells and time to neutrophil engraftment. But, a further study on the value of expansion potential is required because there is an inverse tendency.
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