药物代谢组学指导肾移植患者他克莫司个体化用药及机制研究

Inter-individual variation in drug response is influenced not only by genotype but also by environmental factors. Obviously, it is not enough to achieve personalized drug therapy using pharmacogenomic approach alone. In recent years， ‘Pharmaco-metabonomics’ modeling, which is defined as ‘the prediction of the outcome of a drug or xenobiotic intervention in an individual based on a mathematical model of pre-intervention metabolite signatures', is considered as a potentially effective approach for personalizing drug treatment. In this study, the pharmaco-metabonomic approach is used to predict the interindividual variability of steady-state trough concentration and pharmacodynamics of tacrolimus, the first-line immunosuppressant in kidney transplant patients, and to explore the underlying molecular mechanisms. Metabolomics in pre-dose baseline serum is performed on kidney transplant patients. Correlation analysis is conducted with data relating to predose serum metabolites to predict the steady-state trough concentration and pharmacodynamic parameters of tacrolimus and to select the metabolites that substantially contributed to such prediction. The selection of these metabolites allows us to generate mathematical models for clinical prediction. Metabolomic analysis and pharmacodynamic experiments of CD4+ T cells, which are the target cells of tacrolimus and are separated from the pre-dose baseline blood of kidney transplant patients, are performed in vitro to screen for potential markers. The molecular mechanisms of pharmacokinetics- pharmacodynamics individual variation are explored using metabolic network analysis of these markers. This research is of great theoretical and practical significance to facilitate individualized drug therapy and provide in-depth understanding of pharmacokinetics-pharmacodynamics individual variation of tacrolimus.

药物治疗的个体差异的产生受遗传因素和环境因素的共同影响，单纯利用基因组学预测药物的个体差异显然是不够的。近年来提出的药物代谢组学是基于数学模型通过对干预前的代谢物特征的测定来预测药物或者外源性物质给药后的体内结果的研究方法，它在指导临床个体化给药领域有较大潜力。本课题拟利用药物代谢组学预测肾移植病人一线用免疫抑制剂他克莫司的稳态谷浓度/药效学个体差异并探讨其分子机制。通过对肾移植患者给药前血清进行代谢组学测定，与给药后稳态谷浓度和药效指标进行相关分析，找出与稳态谷浓度/药效相关的小分子代谢标志物并建立数学模型。通过分离患者给药前血样中靶细胞即CD4+T细胞进行代谢组学分析和体外药效学实验，寻找靶细胞中特征代谢物，通过代谢通路分析探索他克莫司药代动力学-药效个体化差异的分子机制。本课题对于指导临床他克莫司安全合理应用，深入理解其药代动力学-药效个体差异的发生机制，具有重大的理论和现实意义。

他克莫司是器官移植患者一线用免疫抑制剂，但其个体代谢差异较大且治疗窗窄，需要进行临床血药浓度检测调整给药剂量。本课题研究发现虽然他克莫司血药浓度与药效显著相关，但相关性不佳。临床实践中也发现，部分患者即使药代动力学参数处在正常范围，仍然会发生排斥反应或毒副作用。因此临床需要一个或多个更加能反映药效的标志物以减少他克莫司用药导致的排斥反应或毒副作用。本课题以患者的他克莫司稳态谷浓度（C0）作为药代动力学指标，将他克莫司靶蛋白NFAT下游调控基因表达量（NFAT-RGE）作为药效指标，利用基于GC-TOFMS的代谢组学技术平台测定给药后患者的血清中内源性小分子代谢物，通过多维变量模型分析药效/药代动力学高敏感度组和低敏感度组的代谢组学差异，发现两组代谢组学具有显著性差异，其中磷酸、富马酸、胱氨酸、γ-氨基丁酸、油酸、黄嘌呤、亮氨酸、甲硫氨酸、缬氨酸、酪氨酸和异亮氨酸等化合物在两组间存在显著性差异，代谢通路分析表明多个氨基酸代谢通路、氨酰-tRNA生物合成以及氮代谢通路在高敏感组和低敏感组中显著不同。本课题发现的表征患者对他克莫司敏感度的生物标志物对于指导临床他克莫司安全合理应用，深入理解其药代动力学-药效个体差异的发生机制，具有重大的理论和现实意义。