Frost L, Prendergast D, Farrell G
Department of Medicine, University of Sydney, Westmead, New South Wales, Australia.
J Gastroenterol Hepatol. 1989 Jan-Feb;4(1):1-9. doi: 10.1111/j.1440-1746.1989.tb00800.x.
Peripheral blood mononuclear (PBM) cells from patients with halothane hepatitis are unusually susceptible to damage from phenytoin metabolites generated by an in vitro drug metabolising system. In order to provide more information about the nature of this susceptibility factor, the effect of removing calcium ions (Ca2+) from the incubation medium of the test system was examined. Phenytoin metabolites were generated by incubating phenytoin with beta-naphthoflavone-induced rat liver microsomes in the presence of 1,1,1-trichloropropene oxide (TCPO), an epoxide hydrase inhibitor. When PBM cells from patients who had recovered from halothane hepatitis were incubated in this system and then maintained in Ca(2+)-containing tissue culture medium (without alpha-tocopherol) for 16 h, cell death, as measured by trypan blue exclusion, was greatly increased (53% and 78% at 0.06 mmol/l and 0.12 mmol/l phenytoin, respectively) compared with control incubations (TCPO omitted). Removal of Ca2+ from the tissue culture medium effectively abolished reactive metabolite-induced cell death. Resting cytosolic free Ca2+ concentration in PBM cells was also measured using the quin-2 fluorescence method and total Ca2+ content was measured by atomic absorption spectrometry. Although variability appeared greater among patients, mean values for these parameters among 12 patients with halothane hepatitis did not differ from controls. It is concluded that enhanced permeability of PBM cells to extracellular Ca2+ may be an important factor in the pathogenesis of drug metabolite-induced cell death in patients susceptible to halothane hepatitis. Such permeability to Ca2+ is not evident in resting cells and presumably results from an interaction between electrophilic metabolites and the pumps which regulate cell calcium homeostasis.
氟烷性肝炎患者的外周血单核（PBM）细胞对体外药物代谢系统产生的苯妥英代谢物造成的损伤异常敏感。为了提供更多关于这种易感性因素本质的信息，研究了从测试系统的孵育培养基中去除钙离子（Ca2+）的效果。苯妥英代谢物是通过在环氧化物水解酶抑制剂1,1,1 - 三氯丙烯氧化物（TCPO）存在的情况下，将苯妥英与β - 萘黄酮诱导的大鼠肝微粒体一起孵育而产生的。当将已从氟烷性肝炎中康复的患者的PBM细胞在该系统中孵育，然后在含Ca(2+)的组织培养基（不含α - 生育酚）中维持16小时时，通过台盼蓝排斥法测定的细胞死亡与对照孵育（省略TCPO）相比显著增加（在0.06 mmol/l和0.12 mmol/l苯妥英时分别为53%和78%）。从组织培养基中去除Ca2+有效地消除了反应性代谢物诱导的细胞死亡。还使用喹啉 - 2荧光法测量了PBM细胞中静息细胞溶质游离Ca2+浓度，并通过原子吸收光谱法测量了总Ca2+含量。尽管患者之间的变异性似乎更大，但12例氟烷性肝炎患者这些参数的平均值与对照组没有差异。得出的结论是，PBM细胞对细胞外Ca2+的通透性增强可能是氟烷性肝炎易感患者中药物代谢物诱导细胞死亡发病机制中的一个重要因素。这种对Ca2+的通透性在静息细胞中不明显，推测是由亲电代谢物与调节细胞钙稳态的泵之间的相互作用导致的。
