title: Phenotypic assessment of endothelial microparticles in patients with heart failure and after heart transplantation: switch from cell activation to apoptosis.
abstract: BACKGROUND
  Endothelial microparticles (EMPs) are sub-microscopic membrane vesicles that are shed from the surface of endothelial cells during activation, injury and/or apoptosis. Endothelial cells release phenotypically and quantitatively distinct endothelial microparticles (EMPs) in activation and apoptosis. Therefore, the phenotypic assessment of EMPs can provide useful information reflecting the nature of endothelial injury. We tested the hypothesis that heart transplantation (HT) modifies the pattern of endothelial injury seen in patients with congestive heart failure (CHF).
  
  
  METHODS
  Flow cytometry was used to measure EMPs identified by E-selectin (CD62) and platelet-endothelial cell adhesion molecule 1 (CD31) in 23 patients with advanced heart failure and in 23 HT recipients. A cohort of 23 healthy individuals served as controls.
  
  
  RESULTS
  Heart failure patients were found to have significantly higher levels of EMP62E (577 counts/microl) than controls (192 counts/microl) and post-transplant patients (152 counts/microl) (p < 0.0001). Levels of endothelial microparticles expressing CD31 were significantly different among study groups (analysis of variance [ANOVA], p = 0.001). Heart failure patients had significantly higher levels (1,526 counts/microl) than controls (395 counts/microl) (p < 0.01). Levels of EMP31 remained elevated after heart transplant (935 counts/microl) (p = non-significant). The EMP62/EMP31 ratio, an index of activation (high ratio) or apoptosis (low ratio), was significantly different between the groups (ANOVA, p = 0.01). Post-transplant patients had significantly lower ratios (0.16) than CHF patients (0.38) and controls (0.49).
  
  
  CONCLUSIONS
  Cardiac transplantation is associated with a different pattern of endothelial cell injury than that seen in heart failure. The phenotypic assessment of EMPs in post-transplant patients is consistent with increased apoptotic activity.
authors.affiliation: Division of Cardiology, Department of Internal Medicine, University of Miami, Leonard M. Miller School of Medicine, Miami, Florida 33016, USA. agarcia7@med.miami.edu
authors.forename: Santiago
authors.initials: S
authors.lastname: Garcia
authors.forename: Julio
authors.initials: J
authors.lastname: Chirinos
authors.forename: Javier
authors.initials: J
authors.lastname: Jimenez
authors.forename: Freddy
authors.initials: F
authors.lastname: Del Carpio Muñoz
authors.forename: Mariana
authors.initials: M
authors.lastname: Canoniero
authors.forename: Wenchy
authors.initials: W
authors.lastname: Jy
authors.forename: Joaquin
authors.initials: J
authors.lastname: Jimenez
authors.forename: Lawrence
authors.initials: L
authors.lastname: Horstman
authors.forename: Yeon
authors.initials: Y
authors.lastname: Ahn
mesh_terms: D000328:Adult; D000368:Aged; D017209:Apoptosis; D015415:Biomarkers / Q000097:blood; D016022:Case-Control Studies; D002462:Cell Membrane / Q000648:ultrastructure; D019040:E-Selectin / Q000097:blood; D042783:Endothelial Cells / Q000473:pathology* / Q000648:ultrastructure*; D005260:Female; D005434:Flow Cytometry; D006333:Heart Failure / Q000503:physiopathology* / Q000628:therapy*; D016027:Heart Transplantation; D006801:Humans; D008297:Male; D008875:Middle Aged; D010641:Phenotype; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000097:blood
chemical_list: D015415:Biomarkers; D019040:E-Selectin; D019408:Platelet Endothelial Cell Adhesion Molecule-1