Cardioprotective Effects of a Novel Iron Chelator, Pyridoxal 2-Chlorobenzoyl Hydrazone, in the Rabbit Model of Daunorubicin-Induced Cardiotoxicity
作者:Martin Štěrba、Olga Popelová、Tomáš Šimůnek、Yvona Mazurová、Anna Potáčová、Michaela Adamcová、Helena Kaiserová、Přemysl Poňka、Vladimír Geršl
DOI:10.1124/jpet.106.111468
日期:2006.12
Iron chelation is the only pharmacological intervention against anthracycline cardiotoxicity whose effectiveness has been well documented both experimentally and clinically. In this study, we aimed to assess whether pyridoxal 2-chlorobenzoyl hydrazone ( o -108, a strong iron chelator) can provide effective protection against daunorubicin (DAU)-induced chronic cardiotoxicity in rabbits. First, using the HL-60 leukemic cell line, it was shown that o -108 has no potential to blunt the antiproliferative efficacy of DAU. Instead, o -108 itself moderately inhibited cell proliferation. In vivo, chronic DAU treatment (3 mg/kg weekly for 10 weeks) induced mortality (33%), left ventricular (LV) dysfunction, a troponin T rise, and typical morphological LV damage. In contrast, all animals treated with 10 mg/kg o -108 before DAU survived without a significant drop in the LV ejection fraction (63.2 ± 0.5 versus 59.2 ± 1.0%, beginning versus end, not significant), and their cardiac contractility (dP/dtmax) was significantly higher than in the DAU-only group (1131 ± 125 versus 783 ± 53 kPa/s, p < 0.05), which corresponded with histologically assessed lower extent and intensity of myocardial damage. Although higher o -108 dose (25 mg/kg) was well tolerated when administered alone, in combination with DAU it led to rather paradoxical and mostly negative results regarding both cardioprotection and overall mortality. In conclusion, we show that shielding of free intracellular iron using a potent lipophilic iron chelator is able to offer a meaningful protection against chronic anthracycline cardiotoxicity. However, this approach lost its potential with the higher chelator dose, which suggests that iron might play more complex role in the pathogenesis of this disease than previously assumed.
铁螯合是针对蒽环类药物心脏毒性的唯一药理干预,其有效性在实验和临床上均有充分证明。本研究旨在评估吡哆醇2-氯苯酰肼(o-108,一种强效铁螯合剂)是否能有效保护兔子免受多柔比星(DAU)引起的慢性心脏毒性。首先,使用HL-60白血病细胞系的实验表明,o-108并未减弱DAU的抗增殖效果,反而o-108自身适度抑制了细胞增殖。在体内,慢性DAU治疗(每周3 mg/kg,持续10周)导致了33%的死亡率、左心室(LV)功能障碍、肌钙蛋白T升高以及典型的形态学左心室损伤。相比之下,所有在DAU前接受10 mg/kg o-108治疗的动物存活,且左心室射血分数没有显著下降(63.2 ± 0.5% vs 59.2 ± 1.0%,开始与结束,不显著),它们的心脏收缩力(dP/dtmax)显著高于仅DAU组(1131 ± 125 vs 783 ± 53 kPa/s,p < 0.05),这与组织学评估的心肌损伤程度和强度降低相对应。尽管更高剂量的o-108(25 mg/kg)在单独给药时耐受良好,但与DAU联合使用却导致了相对矛盾且大多为负面的结果,无论是在心脏保护还是总体死亡率方面。总之,我们的研究表明,使用一种强效亲脂性铁螯合剂屏蔽细胞内游离铁能够提供对慢性蒽环类药物心脏毒性的显著保护。然而,当螯合剂剂量过高时,这种方法失去了潜力,这提示铁在该疾病的发病机制中可能扮演比以前假设的更复杂的角色。