title: Preclinical transplantation and safety of HS/PCs expanded from human umbilical cord blood.
abstract: OBJECTIVE
  To expand hematopoietic/progenitor stem cells (HS/PCs) from umbilical cord blood (UCB) and prepare the HS/PC product, and analyze preclinical transplantation and safety of HS/PC product.
  
  
  METHODS
  Human bone marrow-derived mesenchymal stem cells (MSCs) were used as feeder cells to expand HS/PCs from UCB in a serum-free culture system. The proliferation potential of HS/PCs was analyzed. The expanded HS/PCs were suspended in the L-15 medium to prepare the HS/PC product. The contamination of bacteria, fungi and mycoplasmas, the infection of exogenous virus, the concentration of bacterial endotoxin, and the SCF residual in HS/PC product were determined. Finally, cells from the HS/PC product with or without bone marrow-derived mesenchymal stem cells (BM-MSCs) were transplanted into the irradiated NOD/SCID mice to determine the in vivo engraftment potential.
  
  
  RESULTS
  After co-culture for 10 d, the total nuclear cells (TNCs) increased 125-fold, and CD34(+) cells increased 43-fold. The granulocyte-macrophage colony- forming cells (GM-CFCs) and erythroid colony-forming cells (E-CFCs) increased 3.3- and 4.7-fold respectively. The expanded cells were collected and prepared as the expanded product of HS/PCs by re-suspending cells in L-15 medium. For preclinical safety, the HS/PC product was analysed for contamination by bacteria, fungi and mycoplasmas, the bacterial endotoxin concentration and the SCF content. The results showed that the HS/PC product contained no bacteria, fungi or mycoplasmas. The bacterial endotoxin concentration was less than the detection limit of 6 EU/mL, and residual SCF was 75 pg/mL. Based on clinical safety, the HS/PC product was qualified for clinical transplantation. Finally, the HS/PC product was transplanted the irradiated mice where it resulted in rapid engraftment of hematopoietic cells.
  
  
  CONCLUSIONS
  HSPC product prepared from UCB in the serum-free culture system with hMSCs as feeder cells should be clinically safe and effective for clinical transplantation.
authors.affiliation: Chun-Juan Guo, Di Hou, Dong-Yan Shi, Yong-Mei Xi, Jin-Fu Wang, College of Life Sciences, Zhejiang University, Hangzhou 310058, Zhejiang Province, China.
authors.forename: Chun-Juan
authors.initials: CJ
authors.lastname: Guo
authors.forename: Ying
authors.initials: Y
authors.lastname: Gao
authors.forename: Di
authors.initials: D
authors.lastname: Hou
authors.forename: Dong-Yan
authors.initials: DY
authors.lastname: Shi
authors.forename: Xiang-Min
authors.initials: XM
authors.lastname: Tong
authors.forename: Dan
authors.initials: D
authors.lastname: Shen
authors.forename: Yong-Mei
authors.initials: YM
authors.lastname: Xi
authors.forename: Jin-Fu
authors.initials: JF
authors.lastname: Wang