Nanopatterned Human Liver BioChips for Drug Hepatotoxicity Screening

开发人体肝脏芯片设备用于药物的快速安全测试药物和非处方药在正常剂量下服用是非常安全的。制药公司花费数十亿英镑确保新开发药物的安全性。这一过程非常昂贵，因为在评估过程中涉及许多步骤，例如检测毒副作用。因为肝脏是人体药物的主要加工工厂，所以对肝脏的副作用是安全性测试的主要焦点。因此，在这些“候选”药物进入人体早期临床试验之前，科学家们要么在动物身上进行药物测试，要么在实验室——在含有肝细胞的培养皿中进行药物测试。这些测试包括观察药物是否被肝脏正常处理，没有任何副作用，或者是否对肝组织有可测量的损害。肝脏是人体最大的内脏器官，含有数十亿个被称为肝细胞的特化肝细胞，它们负责500多种代谢和解毒功能。由有毒药物副产物引起的肝脏损害可能非常严重，甚至导致死亡。在实验室中用于药物测试的最佳肝细胞是从供体人类肝脏中分离出来的正常人类肝细胞。不幸的是，人类捐献器官的短缺意味着很少有肝脏可用于此目的。因此，科学家们正在开发和利用其他类型的肝细胞用于实验室。制药公司经常使用啮齿动物肝细胞进行药物毒性测试。然而，由于物种之间的差异，任何药物毒性作用的数据与人类肝脏的数据并不完全相同，在人类药物试验之前可能会遗漏不安全的副作用。此外，还使用了人类“永生化”细胞系（来自患病肝组织的肝细胞），这些细胞系非常容易生长并用于实验室测试。然而，这些细胞不像肝脏中的健康肝细胞那样发挥功能，因此，像动物肝脏数据一样，可能无法预测潜在的药物诱导的肝毒性。因此，制药公司不断寻找其他类型的肝细胞用于药物毒性测试。在我们的项目中，我们将使用一种名为“HepaRG”的新型人类肝细胞系。这些细胞很特别，因为它们在实验室培养皿中形成两种类型的肝细胞：肝细胞和被称为“胆管细胞”的支持细胞。这是非常重要的，因为在你自己的肝脏中，肝细胞在与邻居接触时表现最好。这实际上允许HepaRG细胞执行许多生化和解毒功能，与前面提到的正常人类肝细胞非常相似。我们在这个项目中的主要目标是使用HepaRG细胞开发一种人体“肝脏芯片”设备，用于药物的快速安全性测试。科学家们知道，在肝脏中，肝细胞实际上也会对它们的微观环境做出反应——即使是在纳米尺度上（人类头发厚度的百万分之一）——以更好地发挥作用。在我们的实验室中，我们已经证明，在特殊的“纳米模式”培养载玻片上培养的细胞通过改变甚至提高其功能特性或生长速度来应对这种环境。使用不同的纳米尺度模式，我们将测试许多载玻片，以找到最能支持和改善肝细胞功能和外观的模式。使用最好的，或者最优的纳米图案的载玻片，然后我们将用一系列已知对肝脏有毒的药物来测试这些载玻片，看看它们是否以类似于正常人类肝细胞的方式作出反应。利用这些信息，我们可以将最好的纳米模式结合到一种新型的“生物芯片”设备中，这种设备可以使用特殊的自动化细胞成像技术进行快速（机器人）药物毒性测试。然后，肝脏生物芯片可以用于测试药物安全性，降低药物开发成本，特别是减少药物研究中动物的使用。

Developing a human liver-on-a-chip device for rapid safety testing of drugsDrugs and over-the-counter medicines are very safe to take at normal dosage. Pharmaceutical companies spend billions of pounds ensuring newly developed drugs are safe. This process is extremely expensive because there are many steps involved in this assessment, e.g. testing for toxic side effects. Because the liver is the body's main processing factory for drugs, side effects on the liver a major focus of safety testing. Accodringly, before these 'candidate' drugs can proceed to early clinical trials in humans, scientists perform drug testing either in animals or in the laboratory - in culture dishes containing liver cells.These tests involve seeing if the drug is processed by the liver normally, without any side-effects, or if there is measurable damage to the liver tissue. The liver is the largest internal organ in the body, containing billions of specialized liver cells, called hepatocytes, which are responsible for over 500 metabolic and detoxification functions. Liver damage caused by toxic drug by-products can be very serious and even lead to death.The best liver cells to use in the lab for drug testing are normal human hepatocytes, isolated from donor human livers. Unfortunately the shortage of human donor organs means very few livers are available for this purpose. As such scientists are developing and exploiting other types of hepatocytes for use in the lab. Drug companies often use rodent hepatocytes for drug toxicity testing. However, due to differences between species, data from any drug toxic effects are not exactly the same as in human liver, potentially missing unsafe side-effects before human drug trials. In addition, human 'immortalized' cell lines are used (hepatocytes derived from sick liver tissue) which are very easy to grow and use for testing in the lab. However, again these cells do not function as healthy hepatocytes do in the liver and therefore, like animal liver data, can fail to predict potential drug-induced liver toxicity. Pharmaceutical companies are therefore constantly searching for other types of hepatocytes for use in drug toxicity testing.In our project, we will use a novel type of human liver cell line called 'HepaRG'. These cells are special because they form two types of liver cells in lab culture dishes: Hepatocytes plus supporting cells called 'cholangiocytes'. This is very important since as in your own liver, hepatocytes perform best when they are in contact with their neighbours. This actually allows HepaRG cells to perform many biochemical and detoxification functions very similar to the normal human hepatocytes mentioned earlier.Our main aim in this project is to use HepaRG cells to develop a human 'liver-on-a-chip' device for rapid safety testing of drugs. Scientists know that in the liver, hepatocytes actually respond also to their microscopic environment - even at the nanoscale (one millionth of the thickness of a human hair) - to function better. In our lab, we have shown that cells cultured on special 'nano-patterned' culture slides respond to this environment by changing or even improving their functional properties or rate of growth.Using different nano-scale patterns we will test many slides to find the pattern which best supports and improves hepatocyte function and appearance. Using the best, or optimal nano-patterned slides, we will then test these using a range of drugs, which are known to be toxic to the liver, to see if they respond in a manner similar to normal human hepatocytes.Using this information, will then allow us to combine the best nano-patterns into a novel 'BioChip' device, which is compatible with rapid (robotic) drug toxicity testing using special automated cell imaging techniques. Liver BioChips could then be used to test drug safety, reduce drug development costs and specifically reduce the use of animals in drug research.