巨核系祖细胞的体外扩增及应用研究

Studies on Ex Vivo Expansion of Megakaryocytic Progenitor and Its Application——Review

如何缩短造血干细胞(hematopoieticstemcells,HSC)移植术后血小板减少的时间,促进血小板恢复,减少出血,是目前造血干细胞移植面临的难题。在巨核细胞系的发育过程中,有多种细胞因子,如血小板生成素(TPO)、巨核细胞生长发育因子(megokaryocytegrowthanddevelopmentfactor,MGDF)、白介素(interleukin,IL)-1、IL-3、IL-6、IL-11、血小板源性生长因子(PDGF)、5-羟色胺(serotonin,5-HT)等发挥了重要作用。近年来巨核祖细胞(MKPC)的体外培养、扩增等研究取得了较大进展,发现通过体外有效扩增巨核祖细胞并移植给患者,可以加快血小板恢复,因此其在HSC移植中有十分重要的意义及良好的应用前景。本文将重点就各种细胞因子对巨核系造血作用和MKPC体外扩增及临床应用进行综述。单独以TPO培养扩增,结果产生的CD41+CD61+细胞比例增高,但细胞总数较低。当加入IL-1β,IL-3,IL-6,Flt-3L时,结果显示CFU-MK扩增400倍,CD34+细胞扩增5-22倍。在包括TPO、IL-1β、IL-3、IL-6和Flt-3L的各种细胞因子组合条件下,加入PDGF的扩增效果最好,且PDGF促进各种细胞包括CD34+、CD41+CD61+、CFU-MK的扩增。PDGF对脐血巨核祖细胞数量的扩增起一定作用,且对脐血MK的成熟没有影响。反映PDGF作用于MKPC的增殖。PDGF可能是促进MKPC体外扩增的合适细胞因子。动物实验显示体外扩增产物在NOD/SCID小鼠中植活并分化。在临床可行性研究中,进行自体PBPC移植的10名癌症患者(8名乳癌和2名非霍奇金氏淋巴瘤患者),接受未处理过的PBPC的同时输注了体外扩增的MK-PC(1-21×105/kgCD61+细胞)。8名患者接受同一供者的异基因血小板输注,4名输注最高数量培养后MKPC的患者中有2名不需要输注血小板,而回顾性对照组14名患者均需输注血小板。总之,巨核祖细胞能在体外扩增并安全输注予自体移植受者。

Application of ex vivo expanded megakaryocytic progenitor cells （ MKPC ） is a strategy for the treatment of thrombocytopenia after hematopoietic stem cell transplantation. Some growth factors including thrombopoietin （TPO）, megakaryocyte growth and development factor （MGDF）, interleukin （IL）-1, IL-3, IL-6, IL-11, platelet-derived growth factor （PDGF）, and serotonin （5-HT） have been demonstrated to play an important role on the regulation of megakaryocyte/platelet development, the efficient conditions for the expansion of the megakaryocyte （MK） progenitors from hematopoietic stem/progenitor cells were discussed in this review article. TPO alone produced a high proportion of MK progenitors but a low total cell count. The addition of IL-1 beta, IL-3, IL-6 and Flt-3L improved the expansion outcome. The combination of three to five cytokines produced more efficient expansions of hematopoietic stem and MK progenitors. PDGF also enhanced the ex vivo expansion of CD61^＋ CD4^＋ cells and CD34^＋ cells in combination with TPO, IL-1 beta, IL-3, IL-6 and Flt-3L. PDGF is a suitable growth factor to improve the ex vivo expansion of MKPC without promoting their in vitro maturation. More importantly, PDGF also enhanced the engraftment of human stem and progenitor cells in NOD/SCID mice. It has been reported that MKPC can be safely administered to autologous peripheral blood progenitor cell transplant recipients. In short, MKPC can be expanded ex vivo and safely applied to autologous transplant.