Ex vivo expansion of megakaryocyte precursors from umbilical cord blood XXXX cells in a closed liquid culture system.

@entity1 @entity26118 @entity6826 @entity11601 @entity1428 @entity2772 @entity1427 @entity2280
Umbilical cord blood (UCB) provides a rich source of stem cells for transplantation after myeloablative therapy. One major disadvantage of UCB transplantation is delayed platelet engraftment. We propose to hasten platelet engraftment by expanding the number of megakaryocyte (MK) precursors ( @entity2280 / @entity1427 cells) through cytokine stimulation within a closed, pre-clinical liquid culture system. Clinical engraftment data suggest a 5- to 10-fold increase in MK precursors in a UCB unit can accelerate platelet engraftment, so this was our goal. Thirteen UCB samples from full-term births were Ficoll-separated and frozen for subsequent use. On thawing, the mononuclear cell population was positively selected for @entity2280 (+) expression. The cells were cultured in gas-permeable Teflon-coated bags in serum-free medium containing the following cytokines: recombinant @entity1 @entity2772 , recombinant @entity1 @entity11601 , recombinant @entity1 @entity6826 , and recombinant @entity1 @entity26118 . MK lineage cell expansion was assessed using mononuclear cell count and flow cytometry ( @entity2280 /41, @entity1427 , @entity2280 /61, and @entity1428 expression) on days 7, 11, and 14. Optimal expansion of @entity2280 /41 and @entity1427 cells was observed at day 11, with a median 6-fold and 33-fold increase in the starting cell doses, respectively. @entity2280 /61 and @entity1428 cell expansion at day 11 was 7-fold and 14-fold, respectively. MK precursors can be successfully expanded from @entity2280 (+) UCB cells in a closed liquid culture system using @entity2772 , recombinant @entity1 @entity11601 , recombinant @entity1 @entity6826 , and recombinant @entity1 @entity26118 to a level that should have a clinical impact in the transplantation setting. Our ex vivo expansion technique needs to be further optimized before it can be used in a pilot UCB transplantation trial.
