Low reactive oxygen species (ROS) levels are well‐established characteristics of mouse hematopoietic stem cells (HSCs). However, little is known about these levels in human HSCs. This study aimed at quantifying ROS levels in human CD34⁺CD38^low and CD34⁺CD38^high human progenitors from bone marrow, cord blood and cells mobilized for autologous HSC transplantation. A specifically devised multiparameter flow cytometry method was used to quantify ROS levels (H₂DCFDA staining) in sub‐populations of primary cells. Results were confirmed by assessing gene expression level of the ROS scavenger GPX3, a key determinant of HSC self‐renewal, in sorted CD34⁺CD38^low and CD34⁺CD38^high cells. CD34⁺CD38^low cells from bone marrow and cord blood displayed significantly lower levels of ROS than CD34⁺CD38^high cells and other leukocytes. Moreover, the correlation between ROS and GPX3 expression was verified in sorted CD34⁺CD38^low and CD34⁺CD38^high cells. These results confirm, in human, data previously reported in mice. Moreover, the flow cytometry assay we developed could allow for a more precise enumeration of repopulating primitive progenitors in the course of HSC transplantation.

中文翻译：

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活性氧水平根据 CD38 表达区分 CD34+ 人类祖细胞。

低活性氧 (ROS) 水平是小鼠造血干细胞 (HSC) 公认的特征。然而，人们对人类 HSC 中的这些水平知之甚少。本研究旨在量化来自骨髓、脐带血和动员用于自体 HSC 移植的细胞的人类 CD34 ⁺ CD38^低和 CD34 ⁺ CD38^高人类祖细胞中的ROS 水平。使用专门设计的多参数流式细胞术方法来量化原代细胞亚群中的ROS 水平（H ₂ DCFDA 染色）。结果通过评估 ROS 清除剂GPX3（HSC 自我更新的关键决定因素）的基因表达水平得到证实，在排序的 CD34 ⁺ CD38^低和 CD34 ⁺ CD38^高细胞。来自骨髓和脐带血的CD34 ⁺ CD38^低细胞显示出显着低于 CD34 ⁺ CD38^高细胞和其他白细胞的 ROS 水平。此外，在分选的 CD34 ⁺ CD38^低和 CD34 ⁺ CD38^高细胞中验证了ROS 和GPX3表达之间的相关性。这些结果在人类中证实了先前在小鼠中报告的数据。此外，我们开发的流式细胞术分析可以在 HSC 移植过程中更精确地计数原始祖细胞的再生。