Lung Tissue Engineering

描述(申请人提供)：肺病，包括肺癌和慢性肺病，如慢性阻塞性肺病，每年造成约28万人死亡(美国肺脏协会)。造成这一死亡率的原因是，由于肺部再生能力有限，所有形式的肺部疾病的治疗都受到阻碍。因此，因退化或感染而受损的肺组织，或通过手术切除的肺组织，在体内不能进行功能性替换。目前，替代肺组织的唯一方法是进行肺移植，这是一种昂贵的手术，10年内只有10%的存活率，而且受到器官严重短缺的阻碍。在过去的三年里，我们一直致力于解决肺组织工程中的一些根本挑战。为了制造一种具有适合肺再生的几何形状和力学性能的肺支架，我们开发了将整个肺组织脱细胞的技术。我们已经证明，这些无细胞肺基质保留了原始肺组织的大体机械性能，并为上皮细胞和血管细胞的黏附和生长提供了突出的支持。我们开发了一种新型的“仿生”生物反应器，它提供了长期无菌肺培养，营养介质通过肺血管腔循环，并将营养介质“呼吸”到呼吸道。作为重新填充无细胞肺基质的细胞来源，我们使用了同基因新生大鼠肺细胞，因为这些细胞在发育中的肺内显示出显著的生长潜力。我们在这项工作中取得了令人振奋的实质性进展，并证明了再生肺组织许多特征的可行性，但在体内测试此类肺组织的功能之前，仍有几个重要问题必须研究和解决。最根本的是，为了交换气体，肺必须包括足够的肺泡扩散表面积，必须在肺泡和其他地方的正确解剖位置上填充功能和分化的上皮细胞亚群，并且必须具有承受生理灌流压力和不向肺泡室渗漏液体的功能性微血管。在这项提案中，我们将研究和完善肺组织工程系统，以解决每个问题，并推进功能肺再生的中心任务，即有效气体交换的能力。我们假设，当无细胞肺基质适当地重新填充肺上皮细胞和血管细胞时，将支持这些细胞的生长和分化，并基于体外测量产生有效的气体交换组织。 公共卫生相关性：包括肺癌在内的肺病和慢性阻塞性肺病等慢性肺病每年共造成约28万人死亡。在过去的三年里，我们一直致力于解决肺组织工程中的一些基本挑战，以便为肺部疾病患者提供肺组织替代。我们假设，无细胞肺基质，当适当地重新填充肺上皮和血管细胞时，将支持这些细胞的生长和分化，并将产生有效的组织，以进行有效的气体交换。

DESCRIPTION (provided by applicant): Lung diseases, including lung cancer and chronic lung diseases such as chronic obstructive pulmonary disease, together account for some 280,000 deaths annually (American Lung Association). Contributing to this mortality is the fact that remediation of all forms of lung disease is hampered by the limited ability of lung to regenerate. Hence, lung tissue that is damaged by degeneration or infection, or lung tissue that is surgically resected, is not functionally replaced in vivo. Currently, the only way to replace lung tissue is to perform lung transplantation, an expensive procedure that is achieves only a 10% survival at 10 years, and one that is hampered by a severe shortage of organs. Over the past 3 years, we have worked to address some fundamental challenges in lung tissue engineering. In order to produce a lung scaffold that has suitable geometry and mechanics for lung regeneration, we have developed technologies to decellularize entire lung tissues. We have shown that these acellular lung matrices retain the gross mechanical properties of the original lung tissues, and provide outstanding support for the adhesion and growth of epithelial and vascular cells. We have developed a novel, "biomimetic" bioreactor that provides for long-term sterile lung culture, circulation of nutrient medium through the lung vascular compartment, and "breathing" of nutrient medium into the airway. As a cell source to repopulate the acellular lung matrix, we have utilized syngeneic neonatal rat lung cells, as these cells show significant potential for growth inside the developing lung. We have made substantial and exciting progress in this work, and have shown the feasibility of regenerating many characteristics of lung tissue, but there remain several important issues that must be studied and addressed before the functionality of such lung tissues can be tested in vivo. Most fundamentally, in order to exchange gas, the lung must comprise sufficient alveolar diffusional surface area, must be populated with functional and differentiated epithelial cell subsets at correct anatomic locations in the alveoli and elsewhere, and must be invested with a functional microvasculature that withstands physiological perfusion pressures and does not leak fluid into the alveolar compartment. In this proposal, we will study and refine the lung tissue engineering system in order to address each of these issues and advance the central mission of functional lung regeneration, which is the capacity for effective gas exchange. We hypothesize that the acellular lung matrix, when suitably re-populated with lung epithelium and vascular cells, will support the growth and differentiation of these cells and will produce a tissue that is effective for gas exchange, based upon in vitro measurements. PUBLIC HEALTH RELEVANCE: Lung diseases, including lung cancer and chronic lung diseases such as chronic obstructive pulmonary disease, together account for some 280,000 deaths annually. Over the past 3 years, we have worked to address some fundamental challenges in lung tissue engineering in order to provide lung tissue replacements for patients with lung disease. We hypothesize that an acellular lung matrix, when suitably re-populated with lung epithelium and vascular cells, will support the growth and differentiation of these cells and will produce a tissue that is effective for functional gas exchange.