Changes in Cell Composition of Umbilical Cord Blood and Functional Activity of Hematopoietic Stem Cells during Cryogenic Storage and Repeated Freezing/Thawing Cycles

Resumo

We analyzed changes in cell composition of umbilical cord blood and functional activity of hematopoietic stem cells during cryogenic storage and after repeated freezing/thawing cycles. It was found that repeated freezing/thawing cycles performed according to the optimal programmable freezing protocol did not significantly affect viability and functional activity of hematopoietic stem cells. When fast freezing program was used, the cells completely lost their capacity to form colonies in semisolid medium, despite high viability parameters in the test with 7-AAD.