Browsing by Subject "extracellular matrix"

Now showing 1 - 3 of 3
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    Feasibility of Pulmonary Airway Tissue Engineering and Repair Using a Cell Spraying Device and Decellularized Porcine Trachea
    (2019-08) Rajendran, Vijay
    Methods for tracheal repair and regeneration are necessary due to the limitations of tracheal resection and reconstruction for certain disorders such as tracheal stenosis, tracheomalacia, and tracheal tumors. Additionally, pulmonary injuries such as airway burns do not have effective treatment options aside from supportive care. The feasibility of a cell spraying device is investigated here as a system for applying human bronchial epithelial cells (HBECs) to decellularized porcine trachea matrices for creation of engineered grafts or as a minimally invasive method for delivering cells for wound healing. HBECs show viability greater than 90% after spraying onto cell culture media or tissue culture plastic. Similarly, one day after spraying onto decellularized trachea, viabilities are seen to be around 90%. Around day three, viabilities were slightly decreased to around 80%. After culturing for over one week, HBECs sprayed onto decellularized trachea displayed a basal cell marker (cytokeratin-5, CK5) and a club cell marker (uteroglobin). Markers for ciliated cells and goblet cells that are crucial for tracheal epithelium could not be found, but this needs to be investigated further. To validate the mechanical performance of the decellularized trachea, compressive resistance testing was performed before and after decellularization of tracheal rings. Results were generally inconclusive with high degrees of variability. A paired sample test conducted with 4 tracheas provided the most interesting results and showed that the decellularization process produced a significantly different compressive resistance compared to the native samples. In practice though this did not seem to be noticeable as the variability found within tracheal samples masked the difference. This would suggest that the decellularization process is not detrimental to the compressive resistance of trachea rings. Based on the results reported here, using a cell spraying device for engineering tracheal grafts and airway epithelial repair seems achievable.
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    Regenerating Pulmonary Vascular Endothelium of Tissue-Engineered Lungs using Endothelial Progenitor Cells and Acellular Scaffolds
    (2021-10) Akinnola, Ifeolu
    Terminal lung diseases damage the organ through substantial irreversible changes to its architecture, leading to a suboptimal level of function. For this patient population, lung transplantation is the primary curative method to re-obtaining their previous quality of life. Relative to other whole organs used for transplant, the acquisition of transplantable lungs is low, resulting in a large deficit of lungs available for patients on the transplant list. Ongoing efforts towards creating functional organs from acellular scaffolds has the potential to address the deficit of lungs. The regeneration of a functional vasculature within acellular organ and tissue scaffolds is a necessity for their overall longevity and function. Current efforts in engineering transplantable lungs with long-term functionality are hindered due to vascular related complications within the newly generated organ. In over to overcome these limitations, improvements in re-endothelialization of scaffolds and acellular tissue are required. The studies described in this thesis provide valuable insight towards characterization of pulmonary endothelial progenitors and cells for re-endothelization, understanding the interaction between endothelial progenitors and vessel-specific extracellular matrices, and the potential for using iPSC-derived angiogenic hemangioblasts for developing vascular endothelium. Within both in vitro culture and acellular murine lung matrices, we have successfully characterized a highly proliferative rat pulmonary endothelial progenitor capable of re-endothelialization of the vasculature without site preference and can be used as a model for identifying progenitors in humans that are suitable for tissue engineering and clinical applications. We continued our efforts by using label-free liquid chromatography-mass spectrometry (LC/MS) analysis of decellularized porcine pulmonary vessels to compare the diversity and abundance of various extracellular matrix (ECM) proteins. The data generated from our LC/MS analysis can be used for future quantitative proteomic analyses. The decellularized ECM from both pulmonary arteries and veins were both used to evaluate their effect on endothelial progenitor maturation, and we were able to detect increase expression of endothelial genes from cells cultured in ECM hydrogels. Finally, we developed a protocol to differentiate human iPSCs into angiogenic hemangioblasts. These differentiated cultures contained sub-populations of CD31+/VEGF2+ and VE-Cadherin+/CD73+ cells. The outcomes from this study will provide guidance for future experiments and insight on characterizing both endothelial progenitors for re-endothelialization and proteomic analysis of pulmonary vasculature ECM.
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    REGULATION OF HYALURONAN TURNOVER IN THE DEVELOPING MAMMARY GLAND AND ITS CONTRIBUTION TO CD44 SIGNALING AND INFLAMMATION IN BREAST CANCER
    (2022-04) Witschen, Patrice
    Cancer has been compared to a chronic wound unable to heal, as the balance is tipped in favor of pro-tumor inflammation. Therefore, it is important to understand how cancer cells interact with and alter their environment to ultimately support disease progression. Hyaluronan (HA) is of particular interest as it is a large glycosaminoglycan of the extracellular matrix that has anti-inflammatory effects under physiologic conditions. However, under conditions of organismal stress, an increase in HA deposition and fragmentation occurs, yet it is unknown how HA deposition impacts malignant progression. We begin by comparing HA machinery within murine mammary glands to aid in our understanding of its aberrant regulation in tumors. To our knowledge, we are the first to characterize HA deposition within the murine mammary gland across key stages of development. Additionally, our findings support a novel role for macrophages in homeostatic and aberrant HA turnover. Furthermore, we demonstrate that breast cancer cells promote cancer-associated inflammation through HA-CD44 interactions, and this axis contributes to early tumor formation. Importantly, our results are supported by data from human breast cancer cases, where increased hyaluronan synthase 2 expression significantly correlates with an inflammatory gene signature. Finally, we define a link between fibroblast growth factor receptor (FGFR)-mediated activation of HA synthesis and HA-CD44 driven macrophage recruitment during early tumorigenesis. Overall, this work establishes essential groundwork for future studies aiming to identify key targets and new therapeutic approaches for the treatment of breast cancer. Because high levels of HA deposition within many tumor types yields a poorer prognosis, our results emphasize that HA-CD44 interactions potentially have broad implications across multiple cancers.