Steady state peripheral blood (SSPB) contains hematopoietic stem and progenitor cells (HSPCs) presenting characteristics of real hematopoietic stem cells, and thus represents an interesting alternative cell supply for hematopoietic cell transplantation. Development of ex vivo expansion strategies could overcome the low HSPC numbers usually rescued from SSPB. We investigated the effect of alpha lipoic acid (ALA) on ex vivo culture of SSPB CD34 positive (CD34pos) cells on primitive cell expansion, cell cycle, and oxidative metabolism as estimated by determining the ROS and GSH content. ALA increased the ex vivo expansion of total CD34pos cells and of phenotypically defined CD34pos HSPCs subpopulations that retained in vivo repopulating capacity, concomitantly to a decreased expansion of differentiating cells. ALA did not modify cell cycle progression nor the proliferation of ex vivo expanded CD34pos cells, and coherently did not affect the ROS level. On the contrary, ALA decreased the proliferation and disturbed cell cycle progression of cells reaching a differentiated status, a phenomenon that seems to be associated with a drop in ROS level. Nonetheless, ALA affected the redox status of hematopoietic primitive cells, as it reproducibly increased GSH content. In conclusion, ALA represents an interesting molecule for the improvement of ex vivo expansion strategies and further clinical application in hematopoietic cell transplantation (HCT).
Keywords: Gluthatione (GSH); Reactive Oxygen Species (ROS); alpha lipoic acid; hematopoietic progenitors; hematopoietic stem cells; oxidative metabolism.