Zhai Qiong Li, Qiu Lu Gui, Li Qian, Meng Heng Xing, Han Jun Ling, Herzig Roger H, Han Zhong Chao
State Key Laboratory of Experimental Hematology, National Research Center of Stem Cell Engineering and Technology, Institute of Hematology & Hospital of Blood Diseases, Chinese Academy of Medical Sciences & Peking Union of Medical College, Tianjin.
Haematologica. 2004 Mar;89(3):265-73.
The homing of stem cells to the bone marrow microenvironment following transplantation is a specific movement eventually leading to the stem cells lodging in specialized niches of hematopoiesis. The present study was designed to develop an ex vivo expansion system capable of preserving the homing potential of hematopoietic stem/progenitor cells (HSPC).
Umbilical cord blood (UCB) CD34+ cells were expanded in QBSF-60 serum-free medium with a simple early-acting combination of cytokines and were re-selected from the expanded products at different time points. The homing-related characteristics and expansion rate of CD34+ cells were simultaneously examined.
It was observed that the number of HSPC increased significantly under our expansion protocol. The expression of CD49d, CD44, CD11a and CD49e on expanded CD34+ cells increased or remained at the same levels as those on freshly isolated CD34+ UCB cells, while the expression of CD54 on expanded CD34+ cells was lower during the second week of culture than at the start. The spontaneous and SDF-1-induced adhesion of CD34+ cells was increased during the first 10 days of culture, with the adhesion rates reaching peak levels (62.8 12.8% and 90.5 11.7% for spontaneous and induced adhesion, respectively) on day 10. Neither spontaneous nor SDF-1-induced migration had changed significantly by day 7.
These data demonstrate that, although ex vivo expansion may alter cell properties, our one-week expansion protocol can preserve most of the homing-related characteristics and activities of UCB HSPC.
移植后干细胞归巢至骨髓微环境是一种特定的迁移过程，最终导致干细胞定位于造血的特定龛位。本研究旨在开发一种能够保留造血干/祖细胞（HSPC）归巢潜能的体外扩增系统。
脐血（UCB）CD34+细胞在含简单早期作用细胞因子组合的QBSF - 60无血清培养基中扩增，并在不同时间点从扩增产物中重新分选。同时检测CD34+细胞的归巢相关特性和扩增率。
在我们的扩增方案下，观察到HSPC数量显著增加。扩增的CD34+细胞上CD49d、CD44、CD11a和CD49e的表达增加或与新鲜分离的UCB CD34+细胞上的表达水平相同，而扩增的CD34+细胞上CD54的表达在培养的第二周低于开始时。在培养的前10天，CD34+细胞的自发和SDF - 1诱导黏附增加，在第10天黏附率达到峰值水平（自发黏附和诱导黏附分别为62.8±12.8%和90.5±11.7%）。到第7天时，自发和SDF - 1诱导的迁移均未发生显著变化。
这些数据表明，尽管体外扩增可能改变细胞特性，但我们的一周扩增方案能够保留UCB HSPC的大部分归巢相关特性和活性。
