A tissue engineered corneal epithelium replacement for animal testing using human stem cells

利用人类干细胞治疗严重疾病或损伤目前正处于快速发展阶段。这项深入的研究已经产生了治疗失明的新方法。英国和日本的科学家们正在培育取自供体角膜（眼睛前部的透明组织）的成体干细胞，将其植入特制的膜上，以培育出新的功能性组织。然后将这些再生组织移植到患病或受伤的眼睛表面，从而恢复患者的视力。人类干细胞的使用不必局限于临床治疗用途，即旨在重建人类视力，它们也可用于大大减少用于医学研究的动物数量。目前，每年需要成千上万只兔子来测试新药和化妆品的潜在毒性。50多年来，用于兔子眼睛测试的方法几乎没有变化。现在，通过利用最近在治疗性干细胞研究方面取得的科学进展，在培养中制造基于人体组织的复制品，我们的目标是开发一种基于人类干细胞的非动物替代药物和纳米材料测试。这样做的好处主要是可以在不伤害任何动物的情况下评估新化学品/材料的影响，而且由于复制组织是由人类干细胞形成的，因此结果也更具代表性。此外，我们的非动物模型可以评估水不溶性材料，如纳米材料，这是动物模型不能很好地做到的。为了开发一种基于人类干细胞的非动物替代药物测试，我们将在一个塑料盘子里重建人眼表面。利用从成人角膜供体组织中分离出的成体干细胞，并以成功应用于角膜干细胞移植的技术为基础，我们将确定一种合适的方案和底物，既能支持体外形成功能性角膜上皮，又能轻易获得。新开发的基于人类干细胞的非动物替代药物测试的适用性将通过对模型对已知有毒和无毒药物的反应进行严格测试来确定。模型对毒性测试的反应将通过显微镜和已建立的毒性试验进行可靠评估。

The use of human stem cells in the treatment of serious disease or injury is currently undergoing a phase of rapid development. This intensive research has already produced new treatments for blindness. UK and Japanese scientists are now growing adult stem cells taken from donor corneas (the transparent tissue at the front of the eye) on specialised membranes to create new functional tissue. These regenerated tissues are then transplanted onto the surface of diseased or injured eyes leading to a restoration of the patients' sight. The use of human stem cells need not be limited to clinical theraputic use i.e. aimed at re-establishing vision in humans, they can aslo be used to significantly reduce the number of animals used in medical research. Presently, thousands of rabbits are needed every year to test for the toxic potential of new drugs and cosmetics. The method used in testing on rabbits eyes has changed little over 50 years. Now, by employing the scientific advancements recently made in therapeutic stem cell research to the manufacture of a human tissue based replica in culture, we aim to develop a human stem cell based non-animal alternative to drug and nanomaterial testing. The advantages of this are primarily that the effect of new chemicals/materials can be assessed without any animals being harmed and since the replica tissue is formed from human stem cells the results are also more representative. Furthermore, our non-animal model can assess water insoluble materials such as nanomaterials, something the animal models can not do well. To develop a human stem cell based non-animal alternative to drug testing we will essentially recreate the surface of the human eye in a plastic dish. Using adult stem cells isolated from adult corneal donor tissue and building upon the techniques sucessfully employed for corneal stem cell transplantation, we will identify a suitable protocol and substrate capable of both supporting the formation of a functional corneal epithelium in vitro and being easily sourced. The suitability of the newly developed human stem cell based non-animal alternative to drug testing will be established by vigorous testing of the model's response to known toxic and non-toxic agents. The model's response to toxicity testing will be robustly assessed by microscopy and established toxicity assays.