title: [Changes of the migration ability of the cord blood CD(34)(+) cells during short-term ex vivo expansion].
abstract: OBJECTIVE
  To study the effect of ex vivo expansion on the migration ability and the CXCR4 expression of umbilical cord blood (CB) hematopoietic stem/progenitor cells (HSPC).
  
  
  METHODS
  CD(34)(+) cells isolated from fresh CB samples were cultured in a serum-free and stroma-free culture system. On day 7, 10 and 14, CD(34)(+) cells were re-selected from the expanded cells, and the expression of CXCR4 and the transmigration ability of these CD(34)(+) cells were evaluated respectively and compared with those of the precultured fresh CD(34)(+) cells.
  
  
  RESULTS
  (1) SDF-1 induced a higher migration percentage of fresh or expanded CB CD(34)(+) cells than that of uninduced ones. (2) Both of the uninduced and SDF-1-induced migrations were slightly reduced in the first week and then much more reduced in the second week expansion (P < 0.05). (3) The number of the CD(34)(+)CXCR4(+) cells were significantly increased during the culture period, but there was a downtrend of CXCR4 expression on CD(34)(+) subset; the expression levels on day 10 and 14 were lower than that on day 0.
  
  
  CONCLUSIONS
  The expanded HSPC would sustain the chemotactic activity during one-week-culture, but with further extended culture time their intrinsic homing potential would be partly impaired.
authors.affiliation: State Key Laboratory of Experimental Hematology, Institute of Hematology & Blood Diseases Hospital, CAMS and PUMC, Tianjin 300020, China.
authors.forename: Qiong-Li
authors.initials: QL
authors.lastname: Zhai
authors.forename: Ya-Fei
authors.initials: YF
authors.lastname: Wang
authors.forename: Qian
authors.initials: Q
authors.lastname: Li
authors.forename: Yong-Jun
authors.initials: YJ
authors.lastname: Liu
authors.forename: Zhen
authors.initials: Z
authors.lastname: Yu
authors.forename: Yu
authors.initials: Y
authors.lastname: Zhou
authors.forename: Heng-Xing
authors.initials: HX
authors.lastname: Meng
authors.forename: Lu-Gui
authors.initials: LG
authors.lastname: Qiu
authors.forename: Zhong-Chao
authors.initials: ZC
authors.lastname: Han
mesh_terms: D018952:Antigens, CD34 / Q000235:genetics / Q000378:metabolism*; D018929:Cell Culture Techniques; D002465:Cell Movement; D002478:Cells, Cultured; D005260:Female; D005312:Fetal Blood / Q000166:cytology* / Q000378:metabolism; D006412:Hematopoietic Stem Cells / Q000166:cytology* / Q000378:metabolism; D006801:Humans; D008297:Male; D011247:Pregnancy
chemical_list: D018952:Antigens, CD34