Endothelial dysfunction is common in acute and chronic organ injury.
Isoflurane is a widely used halogenated volatile
anesthetic during the
perioperative period and protects against endothelial cell death and
inflammation. In this study, we tested whether
isoflurane induces endothelial
ecto-5'-nucleotidase (CD73) and cytoprotective
adenosine generation to protect against endothelial cell injury. Clinically relevant concentrations of
isoflurane induced CD73 activity and increased
adenosine generation in cultured human umbilical vein or mouse glomerular endothelial cells. Surprisingly,
isoflurane-mediated induction of endothelial CD73 activity occurred within 1 hr and without synthesizing new CD73. We determined that
isoflurane rapidly increased CD73 containing endothelial microparticles into the cell
culture media. Indeed, microparticles isolated from
isoflurane-treated endothelial cells had significantly higher CD73 activity as well as increased CD73
protein. In vivo, plasma from mice anesthetized with
isoflurane had significantly higher endothelial cell-derived CD144+ CD73+ microparticles and had increased microparticle CD73 activity compared to plasma from
pentobarbital-anesthetized mice. Supporting a critical role of CD73 in
isoflurane-mediated endothelial protection, a selective CD73 inhibitor (
APCP) prevented
isoflurane-induced protection against human endothelial cell
inflammation and apoptosis. In addition,
isoflurane activated endothelial cells
Rho kinase evidenced by
myosin phosphatase target subunit-1 and
myosin light chain phosphorylation. Furthermore,
isoflurane-induced release of CD73 containing microparticles was significantly attenuated by a selective
Rho kinase inhibitor (
Y27632). Taken together, we conclude that the volatile
anesthetic isoflurane causes
Rho kinase-mediated release of endothelial microparticles containing preformed CD73 and increase
adenosine generation to protect against endothelial apoptosis and
inflammation.