Evaluating drug metabolism and drug-drug interactions in a microscale model of hu

描述（由申请人提供）：肝毒性是药物化合物（如Rezulin， Prexige）上市前和上市后损耗的主要原因。器官功能的显著物种特异性差异现在需要用旨在评估人类对药物反应的分析来补充动物数据。原代人肝细胞的贴壁培养被认为是评估临床前药物代谢、酶诱导和肝脏特异性毒性的金标准。然而，在常规培养条件下，肝细胞表现出肝脏特异性功能的快速下降（数小时）。最近，一种强大的人类肝脏组织模型已经开发出来，该模型具有优化的微尺度结构，具有行业标准的多孔格式，可在体外保留肝脏特异性功能4-6周。这个微尺度平台中的肝细胞分泌肝脏特异性产物，显示功能性CYP450和偶联酶，将分子分泌到胆管中，并保持与评估药物处置相关的肝脏特异性基因的高水平表达。这个小企业创新研究（SBIR）第一阶段项目的主要目标是评估微型组织在体外评估药物代谢和药物-药物相互作用方面的效用，与传统的、衰退的培养相比，它具有更好的临床预测性。特别是，广泛的I期和II期酶的非诱导（基线）活性的时间过程将首先在微尺度组织中进行表征，以确定药物代谢应用的最佳时间窗口。然后，将利用微尺度组织来评估药物化合物对I、II和III期转录物和蛋白质活性的时间依赖性调节，以筛选药物开发中的药物-药物相互作用。最后，将探讨微尺度肝组织在预测体内代谢清除率和识别所有主要和次要代谢物方面比传统系统更好的效用。这项SBIR可行性研究的结果将使小型企业能够与主要制药公司建立战略伙伴关系，将微型人体肝脏组织推向市场。在未来，微尺度肝组织可以用于在药物开发的早期消除有问题的化合物，从而大大降低开发成本（每成功上市的药物10亿美元），增加临床成功的可能性，并限制患者接触不安全药物。微型人体肝脏组织也可能使药物作用机制的研究成为可能，允许鉴定新的生物标志物，并使研究能够评估与暴露于药物混合物相关的风险。公共卫生相关性：对肝脏的毒性是监管机构从市场上撤下药物（如Rezulin， Prexige）的主要原因。该SBIR一期项目提出的研究可以建立微尺度人类肝脏组织在药物开发中评估候选药物肝脏特异性代谢的实用性，并且比现有的传统模型系统具有更高的临床预测性。因此，在未来，微型人体肝脏组织可能会在药物开发过程中更早地消除有问题的化合物，从而减少患者在临床试验和市场上接触不安全药物的机会。

DESCRIPTION (provided by applicant): Liver toxicity is the leading cause of pre-launch and post-market attrition of pharmaceutical compounds (i.e. Rezulin, Prexige). Significant species-specific differences in organ functions now necessitate supplementation of animal data with assays designed to assess human responses to drugs. Adherent cultures of primary human hepatocytes are considered to be the gold standard for evaluating preclinical drug metabolism, enzyme induction, and liver-specific toxicity. However, hepatocytes display a rapid (hours) decline in liver-specific functions under conventional culture conditions. Recently, a robust model of human liver tissue has been developed with optimized microscale architecture in an industry-standard multiwell format that retains liver-specific functions for 4-6 weeks in vitro. Hepatocytes in this microscale platform secrete liver- specific products, display functional CYP450 and conjugation enzymes, secrete molecules into the bile canaliculi, and maintain high levels of expression of liver-specific genes relevant for evaluating drug disposition. The primary objective of this Small Business Innovation Research (SBIR) Phase I project is to assess the utility of microscale tissues for evaluating drug metabolism and drug-drug interactions in vitro with better clinical predictivity than that afforded by conventional, declining cultures. In particular, the time course of un-induced (baseline) activities of a broad range of Phase I and II enzymes will first be characterized in microscale tissues to determine the optimal time window for drug metabolism applications. Then, the utility of microscale tissues for evaluating time-dependent modulation of Phase I, II, and III transcripts and protein activities by pharmaceutical compounds will be evaluated towards screening drug-drug interactions in drug development. Lastly, the utility of microscale liver tissues to predict in vivo metabolic clearance and identify all major and minor metabolites better than conventional systems will be explored. The results of this SBIR feasibility study will enable the small business to form strategic partnerships with major pharmaceutical companies towards dissemination of microscale human liver tissues into the marketplace. In the future, microscale liver tissues may be used to eliminate problematic compounds much earlier in drug development towards substantially reducing development costs ($1 billion per successfully marketed drug), increasing the likelihood of clinical success, and limiting patient exposure to unsafe drugs. Microscale human liver tissues may also enable the investigation of mechanisms of drug action, allow identification of new biomarkers, and enable studies to assess the risk associated with exposure to mixtures of drugs. PUBLIC HEALTH RELEVANCE: Toxicity to the liver is the leading cause of drug withdrawals (i.e. Rezulin, Prexige) from the marketplace by regulatory agencies. The studies proposed in this SBIR Phase I project can establish utility of microscale human liver tissues for evaluating liver-specific metabolism of candidate drugs in drug development, and significantly more clinically predictive than allowed in existing conventional model systems. Therefore, in the future, microscale human liver tissues may eliminate problematic compounds much earlier in the drug development pipeline towards reducing patient exposure to unsafe drugs in clinical trials and in the marketplace.