Potential Toxicity of Polymyxins in Human Lung Epithelial Cells
Potential Toxicity of Polymyxins in Human Lung Epithelial Cells
复制标题
DOI：
10.1128/aac.02690-16
复制
发表时间：
2017-06-01
影响因子：
4.9
通讯作者：
Li, Jian
中科院分区：
文献类型：
--
作者：
Ahmed, Maizbha U.;Velkov, Tony;Li, Jian
吸入多粘菌素在治疗由多药耐药革兰氏阴性病原体引起的肺部感染时，在实现呼吸道最佳暴露方面具有相当大的效用。目前的多粘菌素吸入疗法是经验性的，经常使用大剂量，可能导致潜在的肺部不良反应。本研究旨在探讨多粘菌素对人肺上皮细胞(A549)的作用。用流式细胞仪检测多粘菌素作用后A549细胞的存活率。观察多粘菌素B对caspase3、8、9的激活、Fas配体(FasL)的表达、线粒体膜电位的丧失以及线粒体的氧化应激。诱导50%最大细胞死亡所需的多粘菌素B浓度为1.74 mM(95%可信区间为1.60~1.90 mM)。粘菌素的毒性至少是多粘菌素B的2倍，而粘菌素甲酯是无毒的。2.0 mM多粘菌素B作用8h后，细胞凋亡率为30.6%+/-11.5%(平均+/-标准差)，24 h时为71.3%+/-3.72%，caspase3、8、9的激活呈浓度和时间依赖性，而caspase9的激活更为显著。此外，多粘菌素B还引起浓度和时间依赖性的FasL表达、线粒体活性氧的产生和线粒体膜电位的改变。这是首次证明外源性死亡受体和内源性线粒体途径都参与了多粘菌素对A549细胞的毒性作用。这一知识基础对于开发安全有效的多粘菌素吸入疗法对抗革兰氏阴性“超级细菌”的新策略至关重要。
Inhaled polymyxins are of considerable utility in achieving optimal exposure in the respiratory tract for the treatment of lung infections caused by multidrug-resistant Gram-negative pathogens. Current inhaled polymyxin therapy is empirical, and often large doses are used that may lead to potential pulmonary adverse effects. This study aimed to investigate the effect of polymyxins on human lung epithelial (A549) cells. The viability of A549 cells was examined after treatment with polymyxins by flow cytometry. Activation of caspases 3, 8, and 9, expression of Fas ligand (FasL), loss of mitochondrial membrane potential, and mitochondrial oxidative stress induced by polymyxin B were evaluated. The concentration of polymyxin B required to induce 50% of maximal cell death was 1.74 mM (95% confidence interval, 1.60 to 1.90 mM). Colistin was at least 2-fold less toxic than polymyxin B, while colistimethate was nontoxic. With 2.0 mM polymyxin B, 30.6% +/- 11.5% (mean +/- standard deviation) of the cells were apoptotic at 8 h and this increased to 71.3% +/- 3.72% at 24 h. Concentration- and time-dependent activation of caspases 3, 8, and 9 was evident, while the activation of caspase 9 was more dramatic. Furthermore, polymyxin B caused concentration- and time-dependent FasL expression, production of mitochondrial reactive oxygen species, and changes in mitochondrial membrane potential. This is the first study to demonstrate that both extrinsic death receptor and intrinsic mitochondrial pathways are involved in polymyxin-induced toxicity in A549 cells. This knowledge base is critical for the development of novel strategies for the safe and effective inhalation therapy of polymyxins against Gram-negative "superbugs."