Activated protein C protects against ventilator-induced pulmonary capillary leak.
The coagulation system is central to the pathophysiology of acute lung injury. We have previously demonstrated that the anticoagulant activated protein C (APC) prevents increased endothelial permeability in response to edemagenic agonists in endothelial cells and that this protection is dependent on the endothelial protein C receptor (EPCR). We currently investigate the effect of APC in a mouse model of ventilator-induced lung injury (VILI). C57BL/6J mice received spontaneous ventilation (control) or mechanical ventilation (MV) with high (HV(T); 20 ml/kg) or low (LV(T); 7 ml/kg) tidal volumes for 2 h and were pretreated with APC or vehicle via jugular vein 1 h before MV. In separate experiments, mice were ventilated for 4 h and received APC 30 and 150 min after starting MV. Indices of capillary leakage included bronchoalveolar lavage (BAL) total protein and Evans blue dye (EBD) assay. Changes in pulmonary EPCR protein and Rho-associated kinase (ROCK) were assessed using SDS-PAGE. Thrombin generation was measured via plasma thrombin-antithrombin complexes. HV(T) induced pulmonary capillary leakage, as evidenced by significant increases in BAL protein and EBD extravasation, without significantly increasing thrombin production. HV(T) also caused significant decreases in pulmonary, membrane-bound EPCR protein levels and increases in pulmonary ROCK-1. APC treatment significantly decreased pulmonary leakage induced by MV when given either before or after initiation of MV. Protection from capillary leakage was associated with restoration of EPCR protein expression and attenuation of ROCK-1 expression. In addition, mice overexpressing EPCR on the pulmonary endothelium were protected from HV(T)-mediated injury. Finally, gene microarray analysis demonstrated that APC significantly altered the expression of genes relevant to vascular permeability at the ontology (e.g., blood vessel development) and specific gene (e.g., MAPK-associated kinase 2 and integrin-beta(6)) levels. These findings indicate that APC is barrier-protective in VILI and that EPCR is a critical participant in APC-mediated protection.
Division of Pulmonary and Critical Care Medicine, 5501 Hopkins Bayview Circle, Baltimore, MD 21224, USA.
James H
JH
Finigan
Adel
A
Boueiz
Emily
E
Wilkinson
Rachel
R
Damico
Jarrett
J
Skirball
Hyun Hae
HH
Pae
Mahendra
M
Damarla
Emile
E
Hasan
David B
DB
Pearse
Sekhar P
SP
Reddy
Dmitry N
DN
Grigoryev
Christopher
C
Cheadle
Charles T
CT
Esmon
Joe G N
JG
Garcia
Paul M
PM
Hassoun
D055371:Acute Lung Injury / Q000209:etiology / Q000378:metabolism* / Q000503:physiopathology; D000818:Animals; D001992:Bronchoalveolar Lavage Fluid; D002196:Capillaries / Q000378:metabolism; D002199:Capillary Permeability / Q000502:physiology; D000074283:Endothelial Protein C Receptor; D015633:Extravascular Lung Water / Q000378:metabolism*; D015870:Gene Expression / Q000502:physiology; D006023:Glycoproteins / Q000235:genetics / Q000378:metabolism*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008817:Mice, Mutant Strains; D020411:Oligonucleotide Array Sequence Analysis; D011486:Protein C / Q000235:genetics / Q000378:metabolism*; D011652:Pulmonary Circulation / Q000502:physiology; D011654:Pulmonary Edema / Q000209:etiology / Q000378:metabolism / Q000503:physiopathology; D011956:Receptors, Cell Surface; D012121:Respiration, Artificial / Q000009:adverse effects*; D013314:Stress, Mechanical; D054460:rho-Associated Kinases / Q000378:metabolism
D000074283:Endothelial Protein C Receptor; D006023:Glycoproteins; C080248:Procr protein, mouse; D011486:Protein C; D011956:Receptors, Cell Surface; C515854:Rock1 protein, mouse; D054460:rho-Associated Kinases