title: Endothelial microparticle levels are similar in acute ischemic stroke and stroke mimics due to activation and not apoptosis/necrosis.
abstract: BACKGROUND
  Endothelial microparticles (EMPs) are <2-microm membranous blebs from endothelial cell membranes that have been demonstrated to be elevated in vasculopathic conditions. One study has demonstrated elevated EMPs in acute ischemic stroke (AIS) versus age- and comorbidity-matched controls.
  
  
  OBJECTIVE
  To determine the level of EMPs in stroke mimics and AIS and determine if EMPs are released as a result of activation or apoptosis/necrosis in AIS.
  
  
  METHODS
  EMP levels in plasma of patients with AIS and stroke mimic patients were quantified by flow cytometry. Stroke status was verified in all patients by magnetic resonance imaging. Patients were matched for age and comorbidities. Markers for apoptosis/necrosis (platelet/endothelial cell adhesion molecule-1 [PECAM-1]/CD31 antigen) and activation (E-selectin/CD62e antigen) were compared. A PECAM-1/E-selectin ratio of >4.0 was used to determine whether EMPs were generated via activation or apoptosis/necrosis. Data were compared between groups using the Mann-Whitney U test.
  
  
  RESULTS
  EMP levels were similar in stroke mimic patients when compared with AIS; there was no difference between groups (PECAM-1, p = 0.393; E-selectin, p = 0.579). The PECAM-1/E-selectin ratio was also similar for AIS and stroke mimics, and all were >4.0.
  
  
  CONCLUSIONS
  EMP levels were similar in patients with AIS and stroke mimic patients. The PECAM-1/E-selectin ratio demonstrated that EMPs were generated via activation and not apoptosis/necrosis. This suggests that EMPs may not be a good marker for AIS, given the inability to discriminate between stroke mimics and AIS.
authors.affiliation: Department of Emergency Medicine, University of Cincinnati, Cincinnati, OH, USA. justin.williams2@amedd.army.mil
authors.forename: Justin B
authors.initials: JB
authors.lastname: Williams
authors.forename: Edward C
authors.initials: EC
authors.lastname: Jauch
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Lindsell
authors.forename: Begoña
authors.initials: B
authors.lastname: Campos
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D017209:Apoptosis / Q000502:physiology*; D015415:Biomarkers / Q000097:blood; D002545:Brain Ischemia / Q000097:blood* / Q000175:diagnosis*; D016022:Case-Control Studies; D003937:Diagnosis, Differential; D019040:E-Selectin / Q000097:blood / Q000378:metabolism; D042783:Endothelial Cells / Q000166:cytology*; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D008297:Male; D008875:Middle Aged; D009336:Necrosis / Q000473:pathology; D010316:Particle Size; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000097:blood; D019038:Platelet Glycoprotein GPIb-IX Complex / Q000378:metabolism; D011336:Probability; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D018709:Statistics, Nonparametric; D020521:Stroke / Q000097:blood* / Q000175:diagnosis*
chemical_list: D015415:Biomarkers; D019040:E-Selectin; D019408:Platelet Endothelial Cell Adhesion Molecule-1; D019038:Platelet Glycoprotein GPIb-IX Complex