Dissecting in vitro models for toxicology

使用组织工程组织和器官作为动物试验的体外替代品越来越重要，特别是在欧洲目前禁止对消费品进行动物试验的背景下（欧盟指令76/768/EEC），预计将在全球范围内推广。 为了标准化用于测试的体外模型，必须小心确保每个“替代品”不仅模仿作为目标的组织结构，而且还共享关键的生化、形态、生理甚至遗传组分。 组织工程方法利用各种合成聚合物到天然生物材料（具有或不具有另外的生物活性辅因子）作为支架以产生适当的三维环境，细胞可以附着在该三维环境上以增殖并分化成在结构上类似于天然组织的生理功能组织。 然而，对“组织形式和结构”（支架）如何调节组织发育和功能的理解有些缺乏，使得模型之间的比较令人生畏，因为不同的组将根据他们选择的模型报告不同的安全性和有效性结果。我们的目标是剖析工程组织中涉及的发育机制，特别是生物材料作为重建整个组织的支架的作用。我们专注于将角膜作为测试平台，因为眼刺激性测试在工业中广泛用于个人使用和家用消费品化合物的安全测试。简单地说，为了便于管理，我们只关注在体外角膜组织工程中通常用作支架的生物材料，以回答以下问题：支架的最佳材料类型是什么-惰性，可降解的合成聚酯，惰性植物纤维或生物相互作用蛋白质？或者，支架是否重要，或者它完全是在优化支架的机械性能或拓扑结构？一旦我们确定了基本支架的基本所需特征，我们将利用这些知识开发1）用于药物疗效测试的体外疾病模型;和2）用于安全性/毒理学测试的角膜模型的全合成类似物。

The use of tissue engineered tissues and organs as in vitro alternatives to animal testing is gaining importance, especially in the context of the ban on animal testing for consumer products currently in place in Europe (EU Directive 76/768/EEC) which is expected to expand worldwide. To standardize in vitro models for testing, care must be taken to assure that each "alternative" not only mimics the tissue architecture as the target, but also shares key biochemical, morphological, physiological, and even genetic components. Tissue engineering methods utilize a wide range of synthetic polymers to natural biomaterials (with or without additional bioactive co-factors) as scaffolding to create appropriate 3-dimensional environments upon which cells can attach to proliferate and differentiate into physiologically functional tissues that are structurally similar to the native tissue. The understanding of how "tissue forms and architecture" (scaffolds) regulates tissue development and function, however, is somewhat lacking, making comparison amongst models daunting, as different groups will report different safety and efficacy results based on the model they have selected. Our objective is to dissect out the developmental mechanisms involved in engineering tissues, specifically the role of biomaterials as scaffolding used in reconstructing whole tissues. We focus on the cornea as a test bed since ocular irritancy testing is widely used in industry for safety testing of compounds for personal use and household consumer products. Very briefly, to keep things manageable, we focus only the biomaterials that are commonly used as scaffolding in in vitro corneal tissue engineering to answer the following questions: What is the best type of material for scaffolds - an inert, degradable synthetic polyester, an inert plant-based fibre or biointeractive protein? Or, does the scaffold matter at all, or it is all in optimization of the mechanical properties or topology of the scaffolding? Once we have identified the fundamental desired characteristics of the basic scaffold, we will use this knowledge to develop 1) an in vitro disease model for drug efficacy testing; and 2) a fully synthetic analog of a corneal model for safety/ toxicology testing.