BACKGROUND Current protocols for transplantation of hematopoietic stem and progenitor cells may be limited by donor-cell availability and the long time needed to restore neutrophil and platelet counts to normal levels. Ex vivo expansion of hematopoietic cells has the potential to decrease the required harvest size, and to enhance the transplant outcome, by providing greater numbers of progenitor and post-progenitor cells. However, widespread application of ex vivo expansion in the clinical setting is complicated by sample-to-sample variability in the extent and kinetics of cell expansion. For example, the lag time before active cell expansion may vary by several days and some samples may never expand under the culture conditions employed. An early determination regarding the fate of a culture would save time and resources, and would allow corrective action to be taken if desired. Furthermore, anticipation of the onset of cell cycling should prove useful in the development of culture-feeding strategies, as well as for maximizing transduction efficiency in gene-therapy protocols that employ retroviral vectors. METHODS We demonstrate that the nuclei-size distribution, which is obtained at the same time as the total nucleated cell concentration, can be used to predict the onset of cell proliferation. The formation of a second peak (with diameter > 4 microm) in the nuclei-size distribution, in addition to the smaller diameter peak (< 4 microm) present for quiescent cells, precedes total cell expansion. RESULTS In particular 94% of all MNC and CD34+ cell cultures that we have observed to exhibit a second peak in the nuclei-size distribution have realized total cell expansion. Furthermore, only one of 67 observed cultures that did not exhibit the formation of a second peak realized total cell expansion. The formation of a second peak in the nuclei-size distribution is evident, either before or on the same day as the presence of a significant fraction of cells in the S-phase of the cell cycle.

中文翻译：

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细胞核大小分布作为造血细胞增殖的预测工具

背景技术目前的造血干细胞和祖细胞移植方案可能受到供体细胞可用性和将中性粒细胞和血小板计数恢复到正常水平所需的长时间的限制。通过提供更多数量的祖细胞和后祖细胞，造血细胞的体外扩增有可能减少所需的收获大小，并提高移植结果。然而，体外扩增在临床环境中的广泛应用由于细胞扩增程度和动力学的样本间差异而变得复杂。例如，活跃细胞扩增前的滞后时间可能会相差几天，并且某些样品在所采用的培养条件下可能永远不会扩增。尽早确定文化的命运将节省时间和资源，并允许在需要时采取纠正措施。此外，对细胞周期开始的预期应证明有助于培养饲养策略的发展，以及在采用逆转录病毒载体的基因治疗方案中最大限度地提高转导效率。方法我们证明了与总有核细胞浓度同时获得的细胞核大小分布可用于预测细胞增殖的开始。细胞核大小分布中的第二个峰值（直径 > 4 microm）的形成，此外还有静止细胞的较小直径峰值（< 4 microm），先于总细胞扩张。结果 特别是，我们观察到的所有 MNC 和 CD34+ 细胞培养物中的 94% 在细胞核大小分布中表现出第二个峰值，已经实现了总细胞扩增。此外，观察到的 67 种培养物中只有一种没有表现出第二个峰的形成，实现了总细胞扩增。在细胞周期的 S 期中存在大量细胞之前或同一天，细胞核大小分布中第二个峰的形成是明显的。