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This Article Full Text Full Text (PDF) All Versions of this Article: 297/5/L881    most recent 90562.2008v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Yalcin, H. C. Articles by Ghadiali, S. N. PubMed PubMed Citation Articles by Yalcin, H. C. Articles by Ghadiali, S. N.

Influence of cytoskeletal structure and mechanics on epithelial cell injury during cyclic airway reopening

¹Mechanical Engineering and BioEngineering, Lehigh University, Bethlehem, Pennsylvania; ; ²Physics Department, Lehigh University, Bethlehem, Pennsylvania; and ; ³Biomedical Engineering, Ohio State University, Columbus, Ohio

Submitted 12 November 2008 ; accepted in final form 14 August 2009

Although patients with acute respiratory distress syndrome require mechanical ventilation, these ventilators often exacerbate the existing lung injury. For example, the cyclic closure and reopening of fluid-filled airways during ventilation can cause epithelial cell (EpC) necrosis and barrier disruption. Although much work has focused on minimizing the injurious mechanical forces generated during ventilation, an alternative approach is to make the EpC less susceptible to injury by altering the cell's intrinsic biomechanical/biostructural properties. In this study, we hypothesized that alterations in cytoskeletal structure and mechanics can be used to reduce the cell's susceptibility to injury during airway reopening. EpC were treated with jasplakinolide to stabilize actin filaments or latrunculin A to depolymerize actin and then exposed to cyclic airway reopening conditions at room temperature using a previously developed in vitro cell culture model. Actin stabilization did not affect cell viability but significantly improved cell adhesion primarily due to the development of more numerous focal adhesions. Surprisingly, actin depolymerization significantly improved both cell viability and cell adhesion but weakened focal adhesions. Optical tweezer based measurements of the EpC's micromechanical properties indicate that although latrunculin-treated cells are softer, they also have increased viscous damping properties. To further investigate the effect of "fluidization" on cell injury, experiments were also conducted at 37°C. Although cells held at 37°C exhibited no changes in cytoskeletal structure, they did exhibit increased viscous damping properties and improved cell viability. We conclude that fluidization of the actin cytoskeleton makes the EpC less susceptible to the injurious mechanical forces generated during cyclic airway reopening.

microbubble flows; surface-tension forces; ventilation-induced lung injury; power-law rheology