There will never be enough donor lungs available to meet current and future transplantation needs. In contrast, de-cellularization of whole cadaveric lungs will result in an intact scaffold that can be re- cellularized with adult stem cells, including induced pluripotent stem cells (iPS), derived from individual patients and subsequently utilized for autologous transplantation. Notably, the de-cellularization process removes cellular antigens responsible for immune rejection and the de-cellularized lungs maintain native airway and alveolar architecture, extracellular matrix protein composition, and pulmonary vascular network. This will provide a potentially limitless supply of unrelated donor cadaveric lungs for use in emphysema and other diseases for which there is currently no effective cure. However, there are several fundamental questions to be addressed for use of human lungs as scaffolds. Key among these is the reliability and reproducibility of the de-cellularization and re-cellularization processes. Unlike homogenous laboratory mice, donor human lungs will come from patients of different ages and from a variety of clinical and disease backgrounds, including a history of smoking, which might influence the nature of the scaffold following de-cellularization or the re-cellularization process itself. Therefore this proposal will focus on determining key differences between de-cellularized lung scaffolds originating from different donors and on discovering key environmental conditions that determine successful re-cellularization of lung scaffolds with human mesenchymal stromal cells (hMSCs) and induced pluripotent stem cells (iPS). Our preliminary data demonstrates that human lung can be successfully de-cellularized and studied by a variety of histological and functional assessments including lung mechanics, surfactant production, vascular perfusion, and epithelial barrier function, as the lungs re-cellularize. Further, preliminary data demonstrates that human mesenchymal stromal cells (hMSCs) and human alveolar epithelial cells (A549 cells) can be successfully inoculated and grown in de-cellularized human lung. These data provide a firm platform for the proposed two Specific Aims. 1) To determine key differences between de-cellularized lung scaffolds obtained from different donors. 2) To optimize conditions for growth and differentiation of hMSCs, and human iPS cells into functional three dimensional lung tissue when inoculated into de-cellularized human lung slices and apply this technology to whole de-cellularized human lungs. (End of Abstract)