Endothelial cells release phenotypically and quantitatively distinct microparticles in activation and apoptosis.
BACKGROUND
Endothelial cells (EC) shed endothelial microparticles (EMP) in activation and apoptosis.


OBJECTIVE
We compared the antigenic expression of EMP species released during activation as compared to apoptosis, in three cell lines.


METHODS
EC from renal and brain microvascular (MiVEC) and coronary macrovascular (MaVEC) origin were incubated with TNF-alpha to induce activation, or deprived of growth factors to induce apoptosis. Antigens expressed on EMP and EC were assayed flow cytometrically and included constitutive markers (CD31, CD51/61, CD105), inducible markers (CD54, CD62E and CD106), and annexin V binding.


RESULTS
It was found that in apoptosis, constitutive markers in EMP were markedly increased (CD31>CD105), with a concomitant decrease in expression in EC. Annexin V EC surface binding and annexin V+ EMP were more sharply increased in apoptosis than in activation. In contrast, in activation, inducible markers in EMP were markedly increased in both EMP and EC (CD62E>CD54>CD106). Coronary MaVEC released significantly less EMP than MiVEC.


CONCLUSIONS
EC release qualitatively and quantitatively distinct EMP during activation compared to apoptosis. Analysis of EMP phenotypic signatures may provide clinically useful information on the status of the endothelium.
Jimenez
Joaquin J
JJ
Wallace H Coulter Platelet Laboratory, Division of Hematology/Oncology, University of Miami School of Medicine, 1600 NW 10th Ave, Mail Code R36A, Miami, FL, USA. jjimenez@med.miami.edu
Jy
Wenche
W
Mauro
Lucia M
LM
Soderland
Carl
C
Horstman
Lawrence L
LL
Ahn
Yeon S
YS
D015703:Antigens, CD / Q000032:analysis; D017209:Apoptosis; D015415:Biomarkers / Q000032:analysis; D001921:Brain / Q000098:blood supply; D002460:Cell Line; D003331:Coronary Vessels; D042783:Endothelial Cells / Q000378:metabolism*; D004730:Endothelium, Vascular / Q000473:pathology*; D005089:Exocytosis; D006801:Humans; D016130:Immunophenotyping; D007668:Kidney / Q000098:blood supply
D015703:Antigens, CD; D015415:Biomarkers