title: Platelet-, monocyte-derived and tissue factor-carrying circulating microparticles are related to acute myocardial infarction severity.
abstract: OBJECTIVE
  Circulating microparticles (cMPs) are phospholipid-rich vesicles released from cells when activated or injured, and contribute to the formation of intracoronary thrombi. Tissue factor (TF, CD142) is the main trigger of fibrin formation and TF-carrying cMPs are considered one of the most procoagulant cMPs. Similar types of atherosclerotic lesions may lead to different types of AMI, although the mechanisms behind are unresolved. Therefore, we aimed to investigate the phenotype of cMPs found in plasma of ACS patients and its relation to AMI severity and thrombotic burden.
  
  
  METHODS
  In a cross-sectional study, two hundred patients aged 75±4 years were included in the study 2-8 weeks after suffering an AMI. Annexin V positive (AV+)-cMPs derived from blood and vascular cells were measured by flow cytometry. Plasma procoagulant activity (TF-PCA) was measured through a chromogenic assay.
  
  
  RESULTS
  STEMI patients (n = 75) showed higher levels of platelet-derived cMPs [CD61+/AV+, CD31+/AV+, CD42b+/AV+ and CD31+/CD42b+/AV+, P = 0.048, 0.038, 0.009 and 0.006, respectively], compared to NSTEMI patients (n = 125). Patients who suffered a heart failure during AMI (n = 17) had increased levels of platelet (CD61+)-and monocyte (CD14+)-derived cMPs carrying TF (CD142+) (P<0.0001 and 0.004, respectively). Additionally, NYHA class III (n = 23) patients showed higher levels of CD142+/AV+, CD14+/AV+ and CD14+/CD142+/AV+ cMPs than those in class I/II (P = 0.001, 0.015 and 0.014, respectively). The levels of these cMPs positively correlated with TF-PCA (r≥0.166, P≤0.027, all).
  
  
  CONCLUSIONS
  Platelets and monocytes remain activated in AMI patients treated as per guidelines and release cMPs that discriminate AMI severity. Therefore, TF-MPs, and platelet- and monocyte-MPs may reflect thrombotic burden in AMI patients.
authors.affiliation: Centre for Clinical Heart Research, Department of Cardiology, Oslo University Hospital Ullevål, Oslo, Norway.|Faculty of Medicine, University of Oslo, Oslo, Norway.|Cardiovascular Research Centre (CSIC-ICCC) and Biomedical Research Institute Sant Pau (IIB-Sant Pau), Barcelona, Spain.
authors.forename: Gemma
authors.identifier: http://orcid.org/0000-0001-6093-0160
authors.initials: G
authors.lastname: Chiva-Blanch
authors.affiliation: Centre for Clinical Heart Research, Department of Cardiology, Oslo University Hospital Ullevål, Oslo, Norway.|Faculty of Medicine, University of Oslo, Oslo, Norway.
authors.forename: Kristian
authors.initials: K
authors.lastname: Laake
authors.affiliation: Centre for Clinical Heart Research, Department of Cardiology, Oslo University Hospital Ullevål, Oslo, Norway.|Faculty of Medicine, University of Oslo, Oslo, Norway.
authors.forename: Peder
authors.initials: P
authors.lastname: Myhre
authors.affiliation: Centre for Clinical Heart Research, Department of Cardiology, Oslo University Hospital Ullevål, Oslo, Norway.
authors.forename: Vibeke
authors.initials: V
authors.lastname: Bratseth
authors.affiliation: Centre for Clinical Heart Research, Department of Cardiology, Oslo University Hospital Ullevål, Oslo, Norway.|Faculty of Medicine, University of Oslo, Oslo, Norway.
authors.forename: Harald
authors.initials: H
authors.lastname: Arnesen
authors.affiliation: Centre for Clinical Heart Research, Department of Cardiology, Oslo University Hospital Ullevål, Oslo, Norway.
authors.forename: Svein
authors.initials: S
authors.lastname: Solheim
authors.affiliation: Cardiovascular Research Centre (CSIC-ICCC) and Biomedical Research Institute Sant Pau (IIB-Sant Pau), Barcelona, Spain.
authors.forename: Lina
authors.initials: L
authors.lastname: Badimon
authors.affiliation: Centre for Clinical Heart Research, Department of Cardiology, Oslo University Hospital Ullevål, Oslo, Norway.|Faculty of Medicine, University of Oslo, Oslo, Norway.
authors.forename: Ingebjørg
authors.initials: I
authors.lastname: Seljeflot
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001792:Blood Platelets / Q000378:metabolism*; D055252:Cell-Derived Microparticles / Q000378:metabolism*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D009000:Monocytes / Q000378:metabolism*; D009203:Myocardial Infarction / Q000097:blood* / Q000175:diagnosis / Q000453:epidemiology; D009664:Norway / Q000453:epidemiology; D012307:Risk Factors; D012720:Severity of Illness Index