title: Differences in cell cycle kinetics of candidate engrafting cells in human bone marrow and mobilized peripheral blood.
abstract: Patients undergoing hematopoietic stem cell transplantation (HSCT) with mobilized peripheral blood (MPB) engraft quicker than those receiving bone marrow (BM). Our objective was to determine whether candidate engrafting cells--primitive hematopoietic progenitors (PHPs)--from MPB and BM exhibit different responses to cytokines that could explain this observation. We compared the cell cycle kinetics and ex vivo expansion of PHP-enriched cells obtained from MPB (n = 12) and BM (n = 10) by fluorescence-activated sorting of CD90+, AC133+ or CD38(dull) subsets of pre-selected CD34(+) cells. Cell cycle status, before and after 40 hours of serum-free culture with a cytokine cocktail, was assessed by multiparameter flow cytometry following incubation with Hoechst 33342 and pyronin Y. We found that 0.2% +/- 0.3% of MPB CD34(+)CD90(+) cells were in S/G(2)/M phases at hour 0, compared with 5% +/- 2.5% of those from BM (p = 0.0001), and 86.3% +/- 9.7% were in G(0), compared with 65.3% +/- 10% of those in BM (p = 0.0001). After 40 hours of culture, CD34(+)CD90(+) cells from MPB were more mitotically active than those from BM, with 29% +/- 4.9% in S/G(2)/M and 20% +/- 11.4% in G(0), compared to 19% +/- 6.5% (p = 0.001) and 39.2% +/- 22% (p = 0.027) of cells from BM. There was greater expansion of both total CD34(+) cells and the CD90(+) subset from MPB samples (p = 0.001 and 0.0001, respectively). Results from PHPs defined on the basis of AC133 expression correlated well with results obtained in CD90(+) subsets (r(2) = 0.81; p = 0.014).MPB PHPs appear to be primed for a greater acceleration in mitotic activity upon cytokine exposure. This qualitative difference may contribute to the earlier engraftment seen after HSCT using MPB grafts.
authors: Divisions of Hematology/Oncology, University Health Network, University of Toronto, 610 University Avenue, Toronto, Ontario M5G 2M9, Canada.
authors: I
authors: I
authors: Thornley
authors: R
authors: R
authors: Nayar
authors: M H
authors: MH
authors: Freedman
authors: D
authors: D
authors: Stephens
authors: M
authors: M
authors: Crump
authors: H A
authors: HA
authors: Messner
authors: D R
authors: DR
authors: Sutherland
mesh_terms: D000071916:AC133 Antigen; D036541:ADP-ribosyl Cyclase; D051997:ADP-ribosyl Cyclase 1; D015703:Antigens, CD; D018952:Antigens, CD34 / Q000032:analysis; D000943:Antigens, Differentiation / Q000032:analysis; D001854:Bone Marrow Cells / Q000166:cytology*; D002453:Cell Cycle; D002469:Cell Separation; D002478:Cells, Cultured; D016207:Cytokines / Q000494:pharmacology; D005434:Flow Cytometry; D006023:Glycoproteins / Q000032:analysis; D018380:Hematopoietic Stem Cell Transplantation; D006412:Hematopoietic Stem Cells / Q000166:cytology*; D006801:Humans; D007700:Kinetics; D008562:Membrane Glycoproteins; D008938:Mitosis; D009244:NAD+ Nucleosidase / Q000032:analysis; D010455:Peptides / Q000032:analysis; D010641:Phenotype; D018800:Thy-1 Antigens / Q000032:analysis; D013997:Time Factors
chemical_list: D000071916:AC133 Antigen; D015703:Antigens, CD; D018952:Antigens, CD34; D000943:Antigens, Differentiation; D016207:Cytokines; D006023:Glycoproteins; D008562:Membrane Glycoproteins; C000606023:PROM1 protein, human; D010455:Peptides; D018800:Thy-1 Antigens; D036541:ADP-ribosyl Cyclase; C498154:CD38 protein, human; D009244:NAD+ Nucleosidase; D051997:ADP-ribosyl Cyclase 1