Neben S, Marcus K, Mauch P
Joint Center for Radiation Therapy, Harvard Medical School, Boston, MA 02115.
Blood. 1993 Apr 1;81(7):1960-7.
Committed progenitor cells and primitive stem cells mediate early and sustained engraftment, respectively, after lethal irradiation and stem cell transplantation. Peripheral blood stem cells (PBSC) from unstimulated mice are deficient in both cell types. To study techniques to mobilize both progenitor cells and primitive stem cells from the marrow to the blood, we collected peripheral blood from C57BL/6 mice 6 to 7 days after a single dose of cyclophosphamide (CY; 200 mg/kg intraperitoneally), after recombinant human granulocyte colony-stimulating factor (rhG-CSF) (250 micrograms/kg/d twice per day subcutaneously for 4 days), or after CY followed by G-CSF. Significant increases in white blood cell counts (1.6- to 2.7-fold) and circulating day 8 colony-forming unit spleen (CFU-S) (11- to 36-fold) were seen with all three mobilization methods compared with unstimulated control mice. Transplantation of mobilized blood stem cells into lethally irradiated hosts decreased the time to erythroid engraftment. Blood stem cells were analyzed for primitive stem cell content by Rs, an assay for CFU-S self-renewal, and competitive repopulation index (CRI), an assay of long-term repopulating ability. The primitive stem cell content of unstimulated blood was clearly deficient, but was significantly increased following mobilization, approaching normal bone marrow levels. These results were confirmed by an in vitro limiting dilution long-term culture assay that measures the frequency of progenitor cells and primitive stem cells. Mobilization following CY + G-CSF was accompanied by a marked loss of both progenitor cells and primitive stem cells in the marrow. In contrast, following G-CSF alone the progenitor cell and primitive stem cell content of the marrow was unchanged. Stem cell mobilization following CY + G-CSF was not affected by previous exposure of donors to cytosine arabinoside or cyclophosphamide, but was significantly reduced by previous exposure to busulfan. These data show that stem cell content in the blood may reach near-normal marrow levels after mobilization, the mobilization from the marrow to the blood is temporary and reversible, the specific technique used may mobilize different subpopulations of stem cells, and the type of prior chemotherapy may influence the ability to mobilize stem cells into the blood.
在致死性照射和干细胞移植后，定向祖细胞和原始干细胞分别介导早期和持续植入。未受刺激小鼠的外周血干细胞（PBSC）在这两种细胞类型上均有缺陷。为了研究将祖细胞和原始干细胞从骨髓动员到血液中的技术，我们在单次给予环磷酰胺（CY；200mg/kg腹腔注射）后6至7天、重组人粒细胞集落刺激因子（rhG-CSF）（250μg/kg/d皮下注射，每天2次，共4天）后或CY加G-CSF后，收集C57BL/6小鼠的外周血。与未受刺激的对照小鼠相比，所有三种动员方法均使白细胞计数显著增加（1.6至2.7倍），循环第8天的脾集落形成单位（CFU-S）增加（11至36倍）。将动员的血液干细胞移植到致死性照射的宿主中可缩短红细胞植入时间。通过Rs（一种CFU-S自我更新的检测方法）和竞争重植指数（CRI，一种长期重植能力的检测方法）分析血液干细胞的原始干细胞含量。未受刺激血液的原始干细胞含量明显不足，但动员后显著增加，接近正常骨髓水平。通过测量祖细胞和原始干细胞频率的体外极限稀释长期培养试验证实了这些结果。CY加G-CSF动员后，骨髓中的祖细胞和原始干细胞均明显减少。相比之下，单独使用G-CSF后，骨髓中的祖细胞和原始干细胞含量未发生变化。CY加G-CSF后的干细胞动员不受供体先前接触阿糖胞苷或环磷酰胺的影响，但先前接触白消安会使其显著降低。这些数据表明，动员后血液中的干细胞含量可能达到接近正常骨髓的水平，从骨髓到血液的动员是暂时且可逆的，所使用的特定技术可能动员不同亚群的干细胞，并且先前化疗的类型可能影响将干细胞动员到血液中的能力。
