Pressure induced lung injury in a novel in vitro model of the alveolar interface: protective effect of dexamethasone.
OBJECTIVE
The lungs of infants born with congenital diaphragmatic hernia suffer from immaturity as well as the short and long term consequences of ventilator-induced lung injury, including chronic lung disease. Antenatal and postnatal steroids are among current strategies promoted to treat premature lungs and limit long term morbidity. Although studied in whole-animal models, insight into ventilator-induced injury at the alveolar-capillary interface as well as the benefits of steroids, remains limited. The present study utilizes a multi-fluidic in vitro model of the alveolar-interface to analyze membrane disruption from compressive aerodynamic forces in dexamethasone-treated cultures.


METHODS
Human alveolar epithelial cell lines, H441 and A549, were cultured in a custom-built chamber under constant aerodynamic shear followed by introduction of pressure stimuli with and without dexamethasone (0.1μM). On-chip bioelectrical measurements were noted to track changes to the cellular surface and live-dead assay to ascertain cellular viability.


RESULTS
Pressure-exposed alveolar cultures demonstrated a significant drop in TEER that was less prominent with an underlying extracellular-matrix coating. Addition of dexamethasone resulted in increased alveolar layer integrity demonstrated by higher TEER values. Furthermore, dexamethasone-treated cells exhibited faster recovery, and the effects of pressure appeared to be mitigated in both cell types.


CONCLUSIONS
Using a novel in vitro model of the alveolus, we demonstrate a dose-response relationship between pressure application and loss of alveolar layer integrity. This effect appears to be alleviated by dexamethasone and matrix sub-coating.
Division Pediatric Surgery, Johns Hopkins Medical Institutions, Baltimore MD; Department of Biomedical Engineering, Johns Hopkins University, Baltimore MD.
Divya D
DD
Nalayanda
Division Pediatric Surgery, Johns Hopkins Medical Institutions, Baltimore MD.
William B
WB
Fulton
Division Pediatric Surgery, Johns Hopkins Medical Institutions, Baltimore MD.
Paul M
PM
Colombani
Department of Biomedical Engineering, Johns Hopkins University, Baltimore MD; Department of Mechanical Engineering, Johns Hopkins University, Baltimore MD.
Tza-Huei
TH
Wang
Division Pediatric Surgery, Johns Hopkins Medical Institutions, Baltimore MD. Electronic address: fa@jhmi.edu.
Fizan
F
Abdullah
D000388:Air; D000399:Air Pressure; D001469:Barotrauma / Q000517:prevention & control*; D001485:Basement Membrane / Q000187:drug effects; D018929:Cell Culture Techniques / Q000295:instrumentation; D002460:Cell Line; D002462:Cell Membrane / Q000187:drug effects; D002470:Cell Survival; D003094:Collagen; D003907:Dexamethasone / Q000008:administration & dosage / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004338:Drug Combinations; D004353:Drug Evaluation, Preclinical; D004847:Epithelial Cells / Q000166:cytology / Q000187:drug effects; D006801:Humans; D007797:Laminin; D011509:Proteoglycans; D011650:Pulmonary Alveoli / Q000166:cytology / Q000187:drug effects*; D012212:Rheology / Q000295:instrumentation; D013499:Surface Properties; D055397:Ventilator-Induced Lung Injury / Q000517:prevention & control*
D004338:Drug Combinations; D007797:Laminin; D011509:Proteoglycans; C059485:matrigel; D003907:Dexamethasone; D003094:Collagen
Air-interface culture; Alveolar cells; Dexamethasone; Pressure-induced injury