Hunnestad J A, Steen R, Tjønnfjord G E, Egeland T
Institute of Transplantation Immunology and Medical Department A., The National Hospital, University of Oslo, Norway.
Stem Cells. 1999;17(1):31-8. doi: 10.1002/stem.170031.
Thrombopoietin (TPO) is established as a powerful stimulant of megakaryocyte differentiation and platelet production both in vivo and in vitro. In preparation for future transplantation of ex vivo expanded CD34+ hematopoietic progenitor cells (HPCs), we have examined the in vitro effect of TPO on cultures of HPC when combined with other early-acting hematopoietic growth factors (GFs) in an attempt to decrease post-transplant thrombocytopenia and accelerate engraftment. By adding TPO to all possible combinations of GM-CSF, IL-3, and c-kit ligand (CKL) in a suspension culture system, we found a significant increase in both relative and absolute numbers of cells in cultures containing TPO of the megakaryocytic lineage and CD34+ cells after 14 days of culture. The most efficient GF combinations for expansion of cell populations of the megakaryocytic lineage and HPCs were TPO, GM-CSF, and CKL, which increased the number of cells of the megakaryocytic lineage 78 fold and the number of CD34+ cells 1.8 fold. The number of CD34+ cells decreased in the cultures containing GM-CSF and CKL with no TPO present, and the number of cells of the megakaryocytic lineage was increased merely 27 fold. Based on our findings, we suggest adding cells from HPCs expanded in cultures containing TPO, GM-CSF, and CKL to unexpanded stem cells for stem cell transplantation.
血小板生成素（TPO）已被确认为在体内和体外均是巨核细胞分化和血小板生成的强大刺激因子。为了为未来的体外扩增CD34+造血祖细胞（HPC）移植做准备，我们研究了TPO与其他早期作用的造血生长因子（GF）联合使用时对HPC培养物的体外作用，以试图减少移植后血小板减少并加速植入。通过在悬浮培养系统中将TPO添加到GM-CSF、IL-3和c-kit配体（CKL）的所有可能组合中，我们发现在培养14天后，含有TPO的培养物中巨核细胞系和CD34+细胞的相对数量和绝对数量均显著增加。用于扩增巨核细胞系和HPC细胞群体的最有效GF组合是TPO、GM-CSF和CKL，它们使巨核细胞系细胞数量增加了78倍，CD34+细胞数量增加了1.8倍。在不含TPO的含有GM-CSF和CKL的培养物中，CD34+细胞数量减少，而巨核细胞系细胞数量仅增加了27倍。基于我们的发现，我们建议将在含有TPO、GM-CSF和CKL的培养物中扩增的HPC细胞添加到未扩增的干细胞中用于干细胞移植。
