Abstract 13333: Imatinib Attenuates LPS-induced Inflammation and Vascular Leakage in Clinically Relevant Murine Models of Acute Lung Injury

Abstract

Introduction: Acute lung injury (ALI) is characterized by inflammation-induced disruption of the endothelial cell (EC) barrier lining the pulmonary vasculature, which causes leakage of fluid and inflammatory cells into the airspaces. The mechanisms underlying ALI are critically dependent on EC cytoskeletal regulation of vascular permeability. The Abl family kinases Abl and Abl Related Gene (Arg) are key mediators of the endothelial cytoskeleton. The pharmaceutical agent imatinib inhibits these kinases and is used clinically for the treatment of multiple different malignancies. Hypothesis: Imatinib attenuates LPS-induced inflammation and vascular leakage in murine ALI and retains its protective properties when combined with high tidal volume (Tv) mechanical ventilation (MV). Methods: As a clinically relevant combination model of ALI stimuli, animals were given intratracheal (i.t) LPS (0.5mg/kg) (vs. PBS), allowed to recover for 20 hours, and then intubated for MV (Tv 30ml/kg, RR 75/min, PEEP 0 cm H2O, 4hrs). Imatinib (75mg/kg) (vs. vehicle) was given i.p. 30 min before LPS and 30 min before MV. For post-injury experiments, imatinib (75mg/kg) (vs. vehicle) was given 4 hours after LPS (1mg/kg) and animals were harvested after 18 hrs. Bronchoalveolar lavage fluid (BAL) was analyzed for total cell counts, neutrophil number, total protein, albumin content, and cytokine levels. Lung tissues were used for MPO activity, albumin content, histology, and Evans Blue dye extravasation. Results: Imatinib attenuated inflammation in both combination model studies and post-LPS treatment studies as measured by BAL cell count, PMN number, MPO activity, TNFα levels, and H&E staining. Additionally, in both models, imatinib decreased vascular leakage as measured by total protein, BAL and lung tissue albumin, and Evans Blue dye extravasation. Conclusions: Imatinib attenuates LPS-induced inflammation and vascular leak in mice. Additionally, imatinib is protective in a clinically relevant murine model of combined LPS and mechanical ventilation injury. Imatinib may have potential for translational use in ALI patients.