Lung Tissue Engineering

描述（由申请人提供）：肺部疾病，包括肺癌和慢性阻塞性肺病等慢性肺部疾病，每年共造成约28万人死亡（美国肺脏协会）。造成这种死亡率的原因是，肺部再生能力有限，阻碍了对所有形式肺部疾病的补救。因此，因退化或感染而受损的肺组织，或手术切除的肺组织，在体内不能在功能上被替换。目前，替代肺组织的唯一方法是进行肺移植，这是一项昂贵的手术，10年存活率只有10%，而且器官严重短缺。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。为了制造一种具有适合肺部再生的几何形状和力学的肺支架，我们已经开发了使整个肺组织脱细胞的技术。我们已经证明，这些脱细胞肺基质保留了原始肺组织的总体力学特性，并为上皮细胞和血管细胞的粘附和生长提供了出色的支持。我们开发了一种新型的“仿生”生物反应器，它提供长期无菌肺培养，营养介质通过肺血管室循环，营养介质“呼吸”进入气道。作为一种细胞来源，我们利用了同基因新生大鼠肺细胞来重新填充脱细胞肺基质，因为这些细胞在发育中的肺内显示出显著的生长潜力。我们在这项工作中已经取得了实质性的和令人兴奋的进展，并且已经显示了再生肺组织的许多特征的可行性，但是在这种肺组织的功能可以在体内测试之前，仍然有几个重要的问题必须研究和解决。最根本的是，为了交换气体，肺必须具有足够的肺泡扩散表面积，必须在肺泡和其他部位的正确解剖位置填充功能性和分化的上皮细胞亚群，并且必须具有功能性微血管，能够承受生理灌注压力并且不会将液体泄漏到肺泡室中。在本提案中，我们将研究和完善肺组织工程系统，以解决这些问题，并推进功能性肺再生的中心任务，即有效气体交换的能力。我们假设，当肺上皮细胞和血管细胞适当地重新填充时，脱细胞肺基质将支持这些细胞的生长和分化，并将产生一个有效的气体交换组织，基于体外测量。

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.