School of Chemical and Bioprocess Engineering, and Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Dublin, Ireland.
J Biotechnol. 2009 Oct 26;144(2):127-34. doi: 10.1016/j.jbiotec.2009.08.017. Epub 2009 Sep 6.
The potential of peripheral blood derived CD34+ cells for ex vivo erythropoiesis was investigated in a stroma-free culture system using a novel strategy of daily passaging. By expanding PB-derived CD34+ cells up to 1.5 x 10(6)-fold this method achieved expansion factors previously only reported for CD34+ cells derived from more potent stem cell sources such as cord blood, bone marrow and mobilized peripheral blood. Analysis of cell surface markers showed differentiation of immature CD34+ cells to populations with 80% CD71-/GpA+ cells and up to 45% enucleated cells, indicating a significant amount of terminal maturation. Cell crowdedness was found to have decisive effects on in vitro erythropoiesis. Cell density per surface area rather than cell concentration per media volume determined cell expansion during exponential growth where more crowded cells showed reduced overall expansion. In late stage erythropoiesis, however, when cells no longer proliferating, increased cell density was seen to enhance cell viability. These results indicate that peripheral blood derived haematopoietic stem cells can be an alternative to cells sourced from bone marrow, cord blood or leukapheresis in terms of expansion potential. This provides distinct advantages in terms of availability for studies of conditions for scale-up and maturation, and may have particular clinical applications in the future.
研究了在无基质培养体系中，通过每日传代的新策略，外周血来源的 CD34+细胞在外周血来源的 CD34+细胞体外红系生成中的潜力。通过将 PB 来源的 CD34+细胞扩增至 1.5 x 10(6)-倍，该方法实现了以前仅在更有效的干细胞来源（如脐带血、骨髓和动员外周血）中报告的 CD34+细胞的扩增倍数。细胞表面标志物分析表明，未成熟的 CD34+细胞分化为具有 80% CD71-/GpA+细胞和高达 45%去核细胞的群体，表明存在大量终末成熟。细胞拥挤度被发现对体外红系生成有决定性影响。细胞密度与表面积的比值而不是细胞浓度与培养基体积的比值决定了指数生长期间的细胞扩增，其中更拥挤的细胞显示出整体扩张减少。然而，在晚期红系生成中，当细胞不再增殖时，增加细胞密度被认为可以提高细胞活力。这些结果表明，外周血来源的造血干细胞在扩增潜力方面可以替代骨髓、脐带血或白细胞分离物来源的细胞。这在可用于扩大规模和成熟条件的研究方面提供了明显的优势，并可能在未来具有特殊的临床应用。
