Endothelium-derived microparticles induce endothelial dysfunction and acute lung injury. Shock 2006 Nov;26(5):464-71
Date
10/19/2006Pubmed ID
17047516DOI
10.1097/01.shk.0000228791.10550.36Scopus ID
2-s2.0-33750375282 (requires institutional sign-in at Scopus site) 150 CitationsAbstract
Acute lung injury (ALI) carries a high mortality in critically ill patients. Recent reports correlate elevated concentrations of endothelium-derived microparticles (EMPs) with diseases of endothelial dysfunction. Many of these diseases have ALI sequelae. We hypothesize that EMPs contribute to endothelial cell (EC) dysfunction and development of ALI. To test this hypothesis, we treated isolated vessels with EMPs and examined changes in vasodilation. Endothelial cell cultures were incubated with EMPs and examined for changes in stimulated nitric oxide (*NO) production and nitric oxide synthase (eNOS) activation. Finally, EMPs were injected into rats and mice and lungs examined for ALI. In both mouse and human ex vivo vessel preparations, we found a marked attenuation of endothelium-mediated vasodilation after EMP treatment (4 x 10(6)/mL). This dysfunction was not corrected by pretreatment of EMPs with free radical scavengers. Coincubation of EMPs with EC cultures yielded a three-fold reduction in A23187-stimulated *NO release. Western analysis of these cells showed a corresponding decrease in eNOS phosphorylation at Ser1179 and a decrease in hsp90 association. Measurements of lung permeability, myeloperoxidase activity, and histology of EMPs-treated Brown Norway rats demonstrated pulmonary edema, neutrophil recruitment, and compromise of the endothelial-alveolar barrier as a second hit phenomenon. In C57BL/6 mice, exogenous EMPs caused a significant rise in pulmonary capillary permeability both as a primary and secondary injury. These findings demonstrate EMPs are capable of inducing significant lung injury at pathophysiologically relevant concentrations. Endothelium-derived microparticles inhibit endothelium-mediated vasodilation and *NO generation from eNOS. Once elucidated, EMP mechanisms of inducing ALI and endothelial dysfunction may present new therapeutic targets.
Author List
Densmore JC, Signorino PR, Ou J, Hatoum OA, Rowe JJ, Shi Y, Kaul S, Jones DW, Sabina RE, Pritchard KA Jr, Guice KS, Oldham KTAuthors
John C. Densmore MD Professor in the Surgery department at Medical College of WisconsinKirkwood A. Pritchard PhD Professor in the Surgery department at Medical College of Wisconsin
MESH terms used to index this publication - Major topics in bold
AnimalsEndothelial Cells
Endothelium
Endothelium, Vascular
Enzyme Activation
Humans
In Vitro Techniques
Male
Mice
Mice, Inbred C57BL
Nitric Oxide
Nitric Oxide Synthase Type III
Particle Size
Rats
Rats, Inbred BN
Vasodilation
