East China University of Science and Technology, Shanghai, People's Republic of China.
J Biotechnol. 2012 Dec 15;164(2):211-9. doi: 10.1016/j.jbiotec.2012.08.007. Epub 2012 Aug 29.
Stem cell factor (SCF) plays important roles in ex vivo expansion of hematopoietic stem cells (HSCs). In this study, the effects of dose and feeding time of SCF on ex vivo expansion of CD34(+) cells were investigated in serum-free medium supplemented with a cytokine cocktail composed of SCF, thrombopoietin (TPO) and flt3-ligand (FL). Among the four tested doses (0, 5, 50 and 500ng/mL), a SCF dose of 50ng/mL was demonstrated to be most favorable for ex vivo expansion of CD34(+) cells, which resulted in 34.22±10.80 and 8.89±1.25 folds of expansion regarding total cells and CD34(+) cells, respectively. Meanwhile, the specific growth rate of cells, the consumption rate of SCF and the percentage of CD34(+)c-kit(+) cells during the 21-day culture process were analyzed. The results indicated that initial 4-day period was a critical stage for SCF functioning on CD34(+) cells during ex vivo expansion. Based on this, a modified SCF feeding regimen was proposed, in which SCF (50ng/mL) was only supplemented on day 0 in the cytokine cocktail and cells were then fed with TPO and FL till the end of culture. It was found that this SCF feeding regimen could expand CD34(+) cells efficiently, thus providing a cost-effect expansion protocol for HSCs.
干细胞因子 (SCF) 在造血干细胞 (HSCs) 的体外扩增中发挥着重要作用。在这项研究中，研究了在含有由干细胞因子 (SCF)、血小板生成素 (TPO) 和 flt3 配体 (FL) 组成的细胞因子鸡尾酒的无血清培养基中，SCF 的剂量和添加时间对 CD34(+)细胞体外扩增的影响。在测试的四个剂量（0、5、50 和 500ng/mL）中，50ng/mL 的 SCF 剂量最有利于 CD34(+)细胞的体外扩增，总细胞和 CD34(+)细胞的扩增倍数分别为 34.22±10.80 和 8.89±1.25。同时，分析了细胞的特定生长速率、SCF 的消耗速率以及在 21 天培养过程中 CD34(+)c-kit(+)细胞的百分比。结果表明，最初的 4 天是 SCF 在体外扩增过程中作用于 CD34(+)细胞的关键阶段。基于此，提出了一种改良的 SCF 喂养方案，其中仅在细胞因子鸡尾酒的第 0 天添加 50ng/mL 的 SCF，然后用 TPO 和 FL 喂养细胞直至培养结束。结果表明，这种 SCF 喂养方案能够有效地扩增 CD34(+)细胞，从而为 HSCs 提供了一种具有成本效益的扩增方案。
