The authors have previously shown that acellular (AC) trachea-lung scaffolds can (1) be produced from natural rat lungs, (2) retain critical components of the extracellular matrix (ECM) such as collagen-1 and elastin, and (3) be used to produce lung tissue after recellularization with murine embryonic stem cells. The aim of this study was to produce large (porcine or human) AC lung scaffolds to determine the feasibility of producing scaffolds with potential clinical applicability. We report here the first attempt to produce AC pig or human trachea-lung scaffold. Using a combination of freezing and sodium dodecyl sulfate washes, pig trachea-lungs and human trachea-lungs were decellularized. Once decellularization was complete we evaluated the structural integrity of the AC lung scaffolds using bronchoscopy, multiphoton microscopy (MPM), assessment of the ECM utilizing immunocytochemistry and evaluation of mechanics through the use of pulmonary function tests (PFTs). Immunocytochemistry indicated that there was loss of collagen type IV and laminin in the AC lung scaffold, but retention of collagen-1, elastin, and fibronectin in some regions. MPM scoring was also used to examine the AC lung scaffold ECM structure and to evaluate the amount of collagen I in normal and AC lung. MPM was used to examine the physical arrangement of collagen-1 and elastin in the pleura, distal lung, lung borders, and trachea or bronchi. MPM and bronchoscopy of trachea and lung tissues showed that no cells or cell debris remained in the AC scaffolds. PFT measurements of the trachea-lungs showed no relevant differences in peak pressure, dynamic or static compliance, and a nonrestricted flow pattern in AC compared to normal lungs. Although there were changes in content of collagen I and elastin this did not affect the mechanics of lung function as evidenced by normal PFT values. When repopulated with a variety of stem or adult cells including human adult primary alveolar epithelial type II cells both pig and human AC scaffolds supported cell attachment and cell viability. Examination of scaffolds produced using a variety of detergents indicated that detergent choice influenced human immune response in terms of T cell activation and chemokine production.

The inability to produce perfusable microvasculature networks capable of supporting tissue survival and of withstanding physiological pressures without leakage is a fundamental problem facing the field of tissue engineering. Microvasculature is critically important for production of bioengineered lung (BEL), which requires systemic circulation to support tissue survival and coordination of circulatory and respiratory systems to ensure proper gas exchange. To advance our understanding of vascularization after bioengineered organ transplantation, we produced and transplanted BEL without creation of a pulmonary artery anastomosis in a porcine model. A single pneumonectomy, performed 1 month before BEL implantation, provided the source of autologous cells used to bioengineer the organ on an acellular lung scaffold. During 30 days of bioreactor culture, we facilitated systemic vessel development using growth factor-loaded microparticles. We evaluated recipient survival, autograft (BEL) vascular and parenchymal tissue development, graft rejection, and microbiome reestablishment in autografted animals 10 hours, 2 weeks, 1 month, and 2 months after transplant. BEL became well vascularized as early as 2 weeks after transplant, and formation of alveolar tissue was observed in all animals ( = 4). There was no indication of transplant rejection. BEL continued to develop after transplant and did not require addition of exogenous growth factors to drive cell proliferation or lung and vascular tissue development. The sterile BEL was seeded and colonized by the bacterial community of the native lung.

Treatment of esophageal disease can necessitate resection and reconstruction of the esophagus. Current reconstruction approaches are limited to utilization of an autologous conduit such as stomach, small bowel, or colon. A tissue engineered construct providing an alternative for esophageal replacement in circumferential, full thickness resection would have significant clinical applications. In the current study, we demonstrate that regeneration of esophageal tissue is feasible and reproducible in a large animal model using synthetic polyurethane electro-spun grafts seeded with autologous adipose-derived mesenchymal stem cells (aMSCs) and a disposable bioreactor. The scaffolds were not incorporated into the regrown esophageal tissue and were retrieved endoscopically. Animals underwent adipose tissue biopsy to harvest and expand autologous aMSCs for seeding on electro-spun polyurethane conduits in a bioreactor. Anesthetized pigs underwent full thickness circumferential resection of the mid-lower thoracic esophagus followed by implantation of the cell seeded scaffold. Results from these animals showed gradual structural regrowth of endogenous esophageal tissue, including squamous esophageal mucosa, submucosa, and smooth muscle layers with blood vessel formation. Scaffolds carrying autologous adipose-derived mesenchymal stem cells may provide an alternative to the use of a gastro-intestinal conduit for some patients following resection of the esophagus.

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Background The accuracy, selectivity and safety of surgical and laser methods for tissue elimination are often limited at microscale. Materials and methods We developed a novel agent, the plasmonic nanobubble (PNB), for optically guided selective elimination of the target tissue with micrometer precision. PNBs were tested in vitro in the two different models of superficial tumors and vascular plaques. Results PNBs were selectively generated around gold nanoparticles (delivered to the target tissues) with short laser pulses. Monolayers of cancerous cells and atherosclerotic plaque tissue were eliminated with PNBs with micrometer accuracy and without thermal and mechanical damage to collateral normal tissues. The effect of the PNB was dynamically controlled through the fluence of laser pulses (532 nm, duration 0.5 and 10 ns) and was guided through the optical scattering by PNB. Conclusions plasmonic nanobubbles were shown to provide precise, tunable, selective and guided ablation of tissue at a microcscopic level and could be employed as a new generation of surgical tools.

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BackgroundPrimary graft dysfunction (PGD) is a significant cause of early morbidity and mortality following lung transplantation. Improved organ preservation techniques will decrease ischemia-reperfusion injury (IRI) contributing to PGD. Adult bone marrow-derived adherent stem cells, including mesenchymal stromal (stem) cells (MSCs) and multipotent adult progenitor cells (MAPCs), have potent anti-inflammatory actions, and we thus postulated that intratracheal MAPC administration during donor lung processing would decrease IRI. The goal of the study was therefore to determine if intratracheal MAPC instillation would decrease lung injury and inflammation in an ex vivo human lung explant model of prolonged cold storage and subsequent reperfusion.MethodsFour donor lungs not utilized for transplant underwent 8 h of cold storage (4°C). Following rewarming for approximately 30 min, non-HLA-matched allogeneic MAPCs (1 × 107 MAPCs/lung) were bronchoscopically instilled into the left lower lobe (LLL) and vehicle comparably instilled into the right lower lobe (RLL). The lungs were then perfused and mechanically ventilated for 4 h and subsequently assessed for histologic injury and for inflammatory markers in bronchoalveolar lavage fluid (BALF) and lung tissue.ResultsAll LLLs consistently demonstrated a significant decrease in histologic and BALF inflammation compared to vehicle-treated RLLs.ConclusionsThese initial pilot studies suggest that use of non-HLA-matched allogeneic MAPCs during donor lung processing can decrease markers of cold ischemia-induced lung injury.Electronic supplementary materialThe online version of this article (doi:10.1186/2047-1440-3-19) contains supplementary material, which is available to authorized users.

We report, for the first time, the development of an organ culture system and protocols to support recellularization of whole acellular (AC) human paediatric lung scaffolds. The protocol for paediatric lung recellularization was developed using human transformed or immortalized cell lines and single human AC lung scaffolds. Using these surrogate cell populations, we identified cell number requirements, cell type and order of cell installations, flow rates and bioreactor management methods necessary for bioengineering whole lungs. Following the development of appropriate cell installation protocols, paediatric AC scaffolds were recellularized using primary lung alveolar epithelial cells (AECs), vascular cells and tracheal/bronchial cells isolated from discarded human adult lungs. Bioengineered paediatric lungs were shown to contain well-developed vascular, respiratory epithelial and lung tissue, with evidence of alveolar-capillary junction formation. Types I and II AECs were found thoughout the paediatric lungs. Furthermore, surfactant protein-C and -D and collagen I were produced in the bioengineered lungs, which resulted in normal lung compliance measurements. Although this is a first step in the process of developing tissues for transplantation, this study demonstrates the feasibility of producing bioengineered lungs for clinical use. Copyright © 2016 John Wiley & Sons, Ltd.