Complete reversal of acid-induced acute lung injury by blocking of platelet-neutrophil aggregation
Alexander Zarbock, … , Kai Singbartl, Klaus Ley
Alexander Zarbock, … , Kai Singbartl, Klaus Ley
Published December 1, 2006
Citation Information: J Clin Invest. 2006;116(12):3211-3219. https://doi.org/10.1172/JCI29499.
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Research Article Pulmonology

Complete reversal of acid-induced acute lung injury by blocking of platelet-neutrophil aggregation

Abstract

Acute lung injury (ALI) causes high mortality, but its molecular mechanisms are poorly understood. Acid aspiration is a frequent cause of ALI, leading to neutrophil sequestration, increased permeability, and deterioration of gas exchange. We investigated the role of platelet-neutrophil interactions in a murine model of acid-induced ALI. Acid aspiration induced P-selectin–dependent platelet-neutrophil interactions in blood and in lung capillaries. Reducing circulating platelets or blocking P-selectin halted the development of ALI. Bone marrow chimeras showed that platelet, not endothelial, P-selectin was responsible for the injury. The interaction of platelets with neutrophils and endothelia was associated with TXA2 formation, with detrimental effects on permeability and tissue function. Activated platelets induced endothelial expression of ICAM-1 and increased neutrophil adhesion. Inhibition of platelet-neutrophil aggregation improved gas exchange, reduced neutrophil recruitment and permeability, and prolonged survival. The key findings were confirmed in a sepsis-induced model of ALI. These findings may translate into improved clinical treatments for ALI.

Authors

Alexander Zarbock, Kai Singbartl, Klaus Ley

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Figure 1

Platelets control PMN recruitment into the lung in acid-induced ALI.

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Platelets control PMN recruitment into the lung in acid-induced ALI. (A–...
(A–C) Platelet depletion (by 40%) prior to acid application by busulfan (n = 4–10 mice per group) significantly improved gas exchange (A), reduced intravascular and interstitial PMN accumulation (data not shown), diminished PMNs in the BAL fluid (B), and partially prevented increased vascular permeability (C). Platelet depletion (85%) caused by a polyclonal Ab diminished PMN recruitment into the alveolar space (B) and permeability (C). (D–G) Photomicrographs of lung tissue. H&E-stained paraffin sections from control mice (D) and mice 2 hours after acid administration (E). Acid application induced increased permeability with an influx of protein-rich fluid and cells (E, arrow) into the alveolar space, swelling of the interstitium, and cell accumulation in the interstitial space (E). Glycol pretreatment (F) prior to initiation of ALI induced the same histological changes seen in untreated mice after acid application whereas the pretreatment with busulfan led to reduced morphological changes (G). Original magnification, ×65. Gly, glycol; Bu, busulfan; pre, preimmune serum; Ab, polyclonal anti-platelet Abs. #P < 0.05. Scale bars, 50.0 mm.