Fibach E, Burke L P, Schechter A N, Noguchi C T, Rodgers G P
Department of Hematology, Hadassah University Hospital, Jerusalem, Israel.
Blood. 1993 Mar 15;81(6):1630-5.
Hydroxyurea (HU), an inhibitor of DNA synthesis, has been shown to increase fetal hemoglobin (HbF) levels in patients with sickle cell anemia and in some patients with beta-thalassemia. However, until now there have not been good in vitro model systems that simulate this effect for study of the molecular and cellular mechanism(s) involved in perturbing the normal ontogeny of the globin genes. We analyzed the cellular effects of HU using a two-phase liquid culture procedure (Fibach et al: Blood 73:100, 1989) in which human peripheral blood-derived progenitor cells undergo proliferation and differentiation. HU was found to have multiple effects on these cultured cells: (1) an increase in the proportion of HbF produced; (2) a decrease in cell number due to inhibition of cell proliferation; (3) an increase in hemoglobin content per cell (mean corpuscular hemoglobin [MCH]); and (4) an increase in cell size (mean corpuscular volume). The extent of these effects was related to the HU dose and time of addition. When added to cell cultures from normal individuals, 4 days following their exposure to erythropoietin (EPO), 100 mumol/L HU caused a 1.3- to 3.5-fold increase in the proportion of HbF, from 0.4% to 5.2% (mean 1.6) in untreated to 1.5% to 8.2% (mean 3.1) in HU-treated cultures and a 45% +/- 10% increase in MCH but only a 25% +/- 7% decrease in cell number on day 13. Cultures of cells derived from five patients with sickle cell anemia have shown a twofold to fivefold increase in the percentage of Hb F following addition of HU while four patients with beta-thalassemia showed a 1.3- to 6.2-fold increase. We believe that this primary cell culture procedure should prove useful in studying the cellular and molecular mechanisms of pharmacologic induction of HbF and might provide a valuable predictive assay system for evaluation of the response of individual patients with hemoglobinopathies to HU and similar agents.
羟基脲（HU）是一种DNA合成抑制剂，已被证明可提高镰状细胞贫血患者和一些β地中海贫血患者的胎儿血红蛋白（HbF）水平。然而，到目前为止，还没有良好的体外模型系统来模拟这种效应，以研究参与干扰珠蛋白基因正常个体发育的分子和细胞机制。我们使用两阶段液体培养程序（Fibach等人：《血液》73:100，1989）分析了HU的细胞效应，在该程序中，人外周血来源的祖细胞经历增殖和分化。发现HU对这些培养细胞有多种作用：（1）产生的HbF比例增加；（2）由于细胞增殖受抑制，细胞数量减少；（3）每个细胞的血红蛋白含量增加（平均红细胞血红蛋白含量[MCH]）；（4）细胞大小增加（平均红细胞体积）。这些作用的程度与HU剂量和添加时间有关。当在正常个体的细胞培养物中，在其暴露于促红细胞生成素（EPO）4天后加入100μmol/L HU时，HbF比例从未处理时的0.4%增加到5.2%（平均1.6），增加了1.3至3.5倍，在HU处理的培养物中从1.5%增加到8.2%（平均3.1），MCH增加了45%±10%，但在第13天时细胞数量仅减少了25%±7%。来自5名镰状细胞贫血患者的细胞培养物在加入HU后，HbF百分比增加了2至5倍，而4名β地中海贫血患者的细胞培养物增加了1.3至6.2倍。我们认为，这种原代细胞培养程序在研究药理诱导HbF的细胞和分子机制方面应被证明是有用的，并且可能为评估血红蛋白病个体患者对HU和类似药物的反应提供一个有价值的预测检测系统。
