Crystal ribcage: development of a platform to probe real-time lung function with cellular resolution in health and disease
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Abstract
The lungs are always in motion and exposed to chemical, mechanical, biological, and immunological stressors creating pathologies at cell scales that effect its functioning. Clinical imaging of the functioning lung includes computed tomography (CT) scans and magnetic resonance imaging (MRI) both of which lack the spatial resolution to image cell- scale dynamics. Histology of the lung provides immense cellular detail, but it is only a snapshot in time lacking all dynamic information. With advances in intravital microscopy, circulatory dynamics of capillaries around alveoli (the functional unit of the lung) have been imaged, however the local respiratory motion was lost as the lung was adhered to the imaging surface by glue or vacuum. The goal of this dissertation was to advance a crystal ribcage — an optically transparent, biocompatible, and physiologically informed housing for a functioning ex vivo lung that can be used for real-time cell-scale optical microscopy. The crystal ribcage was first developed for mouse lungs and used to study altered lung mechanics in metastatic breast cancer, pneumonia, emphysema, and pulmonary fibrosis. Specifically in cancer we found (i) nodular tumors grow into alveoli to limit function while co-optive tumors do not alter function; (ii) the extracellular matrix was highly remodeled in nodular vs co-optive metastatic tumors; (iii) the effect of breathing on single cancer cells trapped in capillaries; and (iv) the critical nodule size that suppresses alveolar function. We scaled up the crystal ribcage from mouse to pig and engineered multiple solutions including reinforcement of the ribcage with slender, rib-like structures, development of a synthetic diaphragm, and finally engineering an active abdomen to actuate the pig lung as close to physiologically as possible. This development pipeline was deployed to fabricate non- human primate and human crystal ribcages as a proof of concept. In summary, mouse, pig, non-human primate and human crystal ribcages were developed by overcoming several engineering challenges. The mouse model was used to study multiple models of pulmonary pathologies, specifically lung cancer metastasis is discussed in this dissertation, and remains an essential tool to study fundamental mechanisms in biology. Applications of the large crystal ribcage model can be closer to clinic and pharmaceutical industries to explore the effect of different ventilation strategies in disease, the effect of proning on lung ventilation and perfusion at alveolar scales, and improved pulmonary drug delivery, engagement, and uptake mechanics prior to full clinical studies.
Description
2025
License
Attribution 4.0 International