title: Endothelial cells release phenotypically and quantitatively distinct microparticles in activation and apoptosis.
abstract: 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.
authors.affiliation: 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
authors.forename: Joaquin J
authors.initials: JJ
authors.lastname: Jimenez
authors.forename: Wenche
authors.initials: W
authors.lastname: Jy
authors.forename: Lucia M
authors.initials: LM
authors.lastname: Mauro
authors.forename: Carl
authors.initials: C
authors.lastname: Soderland
authors.forename: Lawrence L
authors.initials: LL
authors.lastname: Horstman
authors.forename: Yeon S
authors.initials: YS
authors.lastname: Ahn
mesh_terms: 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
chemical_list: D015703:Antigens, CD; D015415:Biomarkers