Establishing the pig as a large animal model for studying drug delivery to the inner ear

项目摘要 在美国，每八个人中就有一个人患有听力损失。听力损失的常见原因是年龄，频繁 暴露在巨大的噪音中，遗传疾病等等。听力损失往往伴随着其他医疗 诸如较高的抑郁率、社会孤立和认知能力下降的状况（例如，痴呆症）。许多 开发了多种新颖的治疗方法来治疗听力损失，但一个共同的挑战是， 所有的共同点是如何安全地将治疗药物输送到内耳。通常，非侵入性的药物递送方法 内耳不能穿透内耳的屏障，因此，只有一小部分药物 到达目标。或者，侵入性手术方法，如直接注射到内耳， 可能会对内耳细胞造成损伤。 尽管啮齿动物模型极大地扩展了我们对听力损失及其分子治疗的理解， 水平，啮齿动物模型不太适合解决药物递送问题。这是因为， 啮齿类动物内耳的厚度，以及其保护屏障的厚度与人类的不匹配，因此， 使用啮齿动物模型评价新药物递送方法的转化潜力是具有挑战性的。 为了解决这一差距，我们想倡导使用猪作为转化动物模型来研究 内耳的非侵入性药物递送策略。猪是大型动物模型，它们的大小，解剖结构， 智力和遗传学比啮齿动物更接近人类。因此，猪正在成为一种流行的 动物模型，其通常用于心血管研究、伤口愈合、器官移植， 营养学研究等等。一般来说，猪很容易用于研究，因为它们是一种流行的形式， 仅在美国，每年就有超过1亿头猪被屠宰。 在这里，为了将猪建立为大型动物模型来研究向内耳的局部递送，我们将：（i）验证 用于药物渗透性研究的离体猪RWM模型。(ii)开发一种方法， 猪模型的中耳和内耳。从技术上讲，我们将利用组织清除和标记技术 与先进的显微镜一起，以细胞分辨率对整个猪内耳进行成像。这 该方法有利于药物在组织中的生物分布。 总的来说，这些目标的成功将为测试微创药物输送方法开辟未来的途径 并在一个大型动物模型中研究体内药物输送。

PROJECT SUMMARY In the US, one out of eight people suffers from hearing loss. Common causes of hearing loss are age, frequent exposure to loud noise, genetic disorders, and more. Hearing loss is often accompanied by other medical conditions such as higher rate of depression, social isolation, and cognitive decline (e.g., dementia). Many diverse and novel therapeutic methods are developed to treat hearing loss, but one common challenge that they all share is how to safely deliver therapeutics to the inner ear. Often, non-invasive methods to deliver drugs to the inner ear cannot penetrate the inner ear’s barriers, and consequently, only a small fraction of the drug reaches its target. Alternatively, invasive surgical methods such as direct injection to the inner ear could potentially cause damage to the cells that populate the inner ear. Although rodent models vastly expanded our understanding of hearing loss and its treatment at a molecular level, rodent models are less suitable to address the drug delivery problem. This is due to the fact that the size of the rodent’s inner ear, and the thickness of its protective barriers do not match the human’s, therefore, evaluation of the translational potential of new drug delivery methods using rodent models is challenging. To address this gap, we would like to advocate for the use of the pig as a translational animal model to study non-invasive drug delivery strategies to the inner ear. Pigs are large animal models, and their size, anatomy, intelligence, and genetics are by far closer to humans than rodents. Consequently, the pig is becoming a popular animal model and it is commonly used in cardiovascular research, wound healing, organ transplantation, nutritional studies, and more. In general, pigs are readily available for research as they are a popular form of livestock, and in the US alone, over 100 million pigs are slaughtered annually. Here, to establish the pig as a large animal model to study local delivery to the inner ear, we will: (i) Validate an ex-vivo porcine RWM model for drug permeability studies. (ii) Develop a method to deliver therapeutics to the middle and inner ear of the porcine model. Technically, we will utilize tissue clearing and labeling techniques together with advanced microscopy to image the whole porcine inner ear with cellular resolution. This methodology facilitates the biodistribution of drugs in the tissue. Overall, the success of these goals will open future avenues for testing minimally invasive drug delivery methods to the inner ear and studying in-vivo drug delivery in a big animal model.