Differences amid bone marrow and cord blood hematopoietic stem/progenitor cell division kinetics

Authors

  • Cláudia Lobato da Silva,

    1. Department of Animal Biotechnology, University of Nevada, Reno, Nevada
    2. IBB–Institute for Biotechnology and Bioengineering, Centre for Biological and Chemical Engineering, Instituto Superior Técnico, Portugal
    Search for more papers by this author
  • Raquel Gonçalves,

    1. Department of Animal Biotechnology, University of Nevada, Reno, Nevada
    2. IBB–Institute for Biotechnology and Bioengineering, Centre for Biological and Chemical Engineering, Instituto Superior Técnico, Portugal
    Search for more papers by this author
  • Christopher D. Porada,

    1. Department of Animal Biotechnology, University of Nevada, Reno, Nevada
    Search for more papers by this author
  • João L. Ascensão,

    1. Department of Medicine, V.A. Medical Center and the George Washington University School of Medicine, Washington, District of Columbia
    Search for more papers by this author
  • Esmail D. Zanjani,

    1. Department of Animal Biotechnology, University of Nevada, Reno, Nevada
    Search for more papers by this author
  • Joaquim M.S. Cabral,

    1. IBB–Institute for Biotechnology and Bioengineering, Centre for Biological and Chemical Engineering, Instituto Superior Técnico, Portugal
    Search for more papers by this author
  • Graça Almeida-Porada

    Corresponding author
    1. Department of Animal Biotechnology, University of Nevada, Reno, Nevada
    • Department of Animal Biotechnology, University of Nevada, Reno, Mail Stop 202, Reno, NV 89557-0104.
    Search for more papers by this author

Abstract

Human hematopoietic stem/progenitor cells (HSC) isolated based upon specific patterns of CD34 and CD38 expression, despite phenotypically identical, were found to be functionally heterogeneous, raising the possibility that reversible expression of these antigens may occur during cellular activation and/or proliferation. In these studies, we combined PKH67 tracking with CD34/CD38 immunostaining to compare cell division kinetics between human bone marrow (BM) and cord blood (CB)-derived HSC expanded in a serum-free/stromal-based system for 14 days (d), and correlated CD34 and CD38 expression with the cell divisional history. CB cells began dividing 24 h earlier than BM cells, and significantly higher numbers underwent mitosis during the time in culture. By d10, over 55% of the CB-cells reached the ninth generation, whereas BM-cells were mostly distributed between the fifth and seventh generation. By d14, all CB cells had undergone multiple cell divisions, while 0.7–3.8% of BM CD34+ cells remained quiescent. Furthermore, the percentage of BM cells expressing CD34 decreased from 60.8 ± 6.3% to 30.6 ± 6.7% prior to initiating division, suggesting that downmodulation of this antigen occurred before commencement of proliferation. Moreover, with BM, all primitive CD34+CD38 cells present at the end of culture arose from proliferating CD34+CD38+ cells that downregulated CD38 expression, while in CB, a CD34+CD38 population was maintained throughout culture. These studies show that BM and CB cells differ significantly in cell division kinetics and expression of CD34 and CD38, and that the inherent modulation of these antigens during ex vivo expansion may lead to erroneous quantification of the stem cell content of the expanded graft. J. Cell. Physiol. 220: 102–111, 2009. © 2009 Wiley-Liss, Inc.

Ancillary