Platelet precursor cells can be generated from cultured human CD34+ progenitor cells but display recirculation into hematopoietic tissue upon transfusion in mice

Abstract

Background: Whereas ex vivo expanded megakaryocytic progenitor cells have been investigated for their ability to support platelet regeneration, the question whether more mature platelet-like particles expanded from hematopoietic progenitor cells may be useful for transfusion purposes remains largely elusive. Methods: Human peripheral blood progenitor cells (PBPCs) were enriched using surface expression of CD34 by immunoselection. CD34+ enriched PBPCs were expanded ex vivo in serum-free medium supplemented with cytokines. As a proof-of-principle, distribution of expanded CD61+ particles was analyzed after transfusion into Non-Obese Diabetic/ Severe Combined Immunodeficiency (NOD/SCID) mice. Results: Highest ex vivo expansion for CD41+/CD61+ cells was achieved when medium was supplemented with SCF, TPO and IL-3. During expansion culture, CD34 marker expression decreased from 85 to 2-8%, while megakaryocytic cells appeared and CD41 and CD61 expression increased from 3 to about 30%. After transfusion of the expanded cells in NOD/SCID mice, CD61+ cells located mainly to bone marrow and to a lesser degree to spleen, but also circulated in blood. Conclusion: Platelet-like particles using cytokine-substituted serumfree medium can be generated efficiently from CD34+ expansion cultures, but mainly home to hematopoietic tissue. Copyright © 2010 S. Karger AG, Basel.