Biophysical Society Thematic Meeting| Lima 2019

Revisiting the Central Dogma of Molecular Biology at the Single-Molecule Level

Poster Abstracts

18-POS Board 18 PULMONARY SURFACTANT DYNAMIC AND BIOPHYSICS BEHAVIOR FROM LUNG INJURED BY MECHANICAL VENTILATION. María José García 1 ; Luciano Amarelle 1 ; Leonel S Malacrida 1,3 ; Arturo J Briva 1,2 ; 1 Hospital de Clínicas, Universidad de la República, Montevideo, Uruguay, Respiratory Research Area, Pathophysiology Department., montevideo, Uruguay 2 Hospital de Clínicas, Universidad de la República, Montevideo, Uruguay., Critical Care Medicine Department., montevideo, Uruguay 3 University of California., Laboratory for Fluorescence Dynamics, Department of Biomedical Engineering., Irvine, CA, USA The alveolar epithelial lining fluid is fundamental for proper respiratory system functionality, in there is located the pulmonary surfactant. Pulmonary surfactant is frequently associated to different degrees of pulmonary injury such lung infection, trauma or induced by mechanical ventilation. Specifically, the respiratory support by mechanical ventilation is strongly associated to a particular kind of lung injury called Ventilation Induced Lung Injury (VILI). During VILI the mechanical stress is transmitted to the pulmonary tissue and the alveolar space affecting the composition and function of pulmonary surfactant.In the present work we study the dynamic performance of the pulmonary surfactant in isolated rat lungs that develops acute lung injury (ALI) by VILI, evaluating the correlations with composition, structural and ventilator parameters of the lung. Our study involves a rat model with different degrees of ALI by changes in ventilator parameters (from protective to harmful mechanical ventilation). The use of isolated lung enables us to control the gas exchange as well as to collect the pulmonary surfactant and lung histology after the protocol. To evaluate the effect of VILI, we measured lung mechanics gas exchange and pulmonary histology. Then the pulmonary surfactant composition and dynamic properties were evaluated using HPLC and Langmuir-Blodgett trough, respectively. The histological analysis shows increased deterioration by alveolar collapse and septum thickness enlargement during the severe VILI. This septum thickness enlargement can be related to the occurrence of pulmonary edema. The phospholipid profile was impaired in the pulmonary surfactant under VILI, mainly related to the phosphatidylcholine. So far, we were able to produce an isolated model of lung ALI by VILI where investigate the effect of mechanical ventilation on pulmonary surfactant at the alveolar interphase. In the future we plan to address the tissue effects by autofluorescence tissue imaging and supramolecular organization of pulmonary surfactant using giant unilamellar vesicles.

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