CELL BIOMECHANICS

Cell Biomechanics

Cell Biomechanics

In addition to cell necrosis, epithelial cell adhesion is critical for maintaining the integrity of the alveolar-capillary barrier. Researchers used histological techniques to qualitatively demonstrate that multiple bubble propagations, which mimic multiple airway reopening events, can disrupt the epithelium. Researchers used fluorescent microscopy techniques to quantitatively demonstrate that although EpC remain adhered to their substrate after one bubble passage, multiple bubble passages can result in significant cell detachment. These authors also demonstrate that multiple reopening events can also result in an increase in cell necrosis. However, there appears to be a critical number of reopening events after which bubble propagations do not induce additional cell necrosis. The authors hypothesize that in this system there exists a sub-set of EpCs that are resistant to microbubble-induced injury. Interestingly, the liquid-plug rupture experiments of Researchers did not appear to cause any significant cell detachment. In addition to the application of different types of hydrodynamic stresses, the long duration culture of primary airway epithelial cells and the cell differentiation that occurred during culture might have “strengthen monolayer integrity via formation of tight junctions and desmosomes”.

Bacterial and viral infections during ARDS can cause detachment of EpC from their basement membrane and may result in sub-confluent monolayers. In addition to the loss of cell-cell contacts, EpC in subconfluent monolayers may exhibit different morphological, typological and/or biomechanical properties which make them more susceptible to injury during airway reopening. Researchers exposed subconfluent and confluent monolayers of EpC to equivalent bubble flow conditions and demonstrated that for a range of reopening velocities, sub-confluent cells experienced significantly more cell necrosis and cell detachment than confluent cells. These authors used measurements of the EpC's aspect ratio to demonstrate that the sub-confluent and confluent cell likely experience the same hydrodynamic stress magnitude and that changes in other biophysical factors might ...