In Vivo Kinetic Biomarkers of Hepatic Toxicity

描述（由申请人提供）： 大量的候选药物增加了对测量肝毒性的新检测方法的需求。我们已经开发出的方法在体内使用2 H2O标记定量多种代谢通量。在这里，我们建议验证这种方法作为毒性筛选。我们将测试14种具有不同作用机制的肝毒素改变肝细胞周转（肝细胞、内皮细胞、总肝细胞）、线粒体生物合成和胶原合成的能力，作为肝损伤和体内平衡的标志物。我们将这些测量与细胞分裂的静态标志物的变化;窦内皮细胞的形态;线粒体细胞色素c;和胶原沉积，分别。我们假设已知影响后者表型的药物的毒性浓度将强烈调节潜在代谢途径中的通量。我们将比较静态标记物和2 H标记物在有限剂量/暴露时间下检测药物诱导的亚临床变化和揭示新毒性活性的能力。最后，我们将筛选预测终末器官损伤的基因表达模式。这项工作将为我们的毒性筛选的监管批准提供坚实的基础，将我们的工作扩展到其他终末器官，并用于人类。

DESCRIPTION (provided by applicant): A flood of drug candidates increases the need for novel assays to measure liver toxicity. We have developed methods for quantifying multiple metabolic fluxes in vivo using 2H2O labeling. Here we propose to validate this approach as a toxicity screen. We will test 14 hepatotoxins with diverse mechanisms of action for their ability to alter liver cell turnover (hepatocytes, endothelial cells, total liver cells), mitochondrial biogenesis, and collagen synthesis as markers of liver damage and homeostasis. We will correlate these measurements with changes in static markers of cell division; morphology of sinusoidal endothelial cells; mitochondrial cytochrome c; and collagen deposition, respectively. We hypothesize that toxic concentrations of drugs known to affect the latter phenotypes will strongly modulate fluxes in the underlying metabolic pathways. We will compare static markers and 2H labeling for their ability to detect drug-induced subclinical changes at limiting doses/exposure times and to reveal novel toxic activities. Finally, we will screen for gene expression patterns that predict end organ damage as detected by our test. This work will provide a solid foundation for regulatory approval of our toxicity screen, for extension of our work to other end organs, and for use in humans.