title: Course of platelet activation and platelet-leukocyte interaction in cerebrovascular ischemia.
abstract: OBJECTIVE
  Platelet activation plays a crucial role in the pathophysiology of cerebral ischemia. The aim of this study was to investigate the contribution of platelet activation and leukocyte-platelet interactions to the disease.
  
  
  METHODS
  One hundred thirty-five patients with transient ischemic attack (TIA) or stroke were enrolled in this single-center study. They underwent cranial computer tomography within 24 hours of clinical onset and after 3 months, and systemic venous blood samples were drawn. Platelet activation (CD62P expression), leukocyte activation (L-selectin expression), and the appearance of platelet-specific antigens on leukocytes as an index of platelet-leukocyte aggregation were measured by flow cytometric techniques in the acute state and at 3-month follow-up.
  
  
  RESULTS
  Patients with a completed stroke or TIA had significantly increased circulating platelet-leukocyte aggregates, increased P-selectin expression on platelets, and decreased L-selectin expression in the acute state compared with the control group (healthy volunteers). No differences in regard to the tested activation markers could be detected between patients with stroke or TIA in the acute phase of the disease. However, platelet and leukocyte activations were normalized after 3 months in patients with TIA, whereas leukocyte activation (reduced L-selectin expression) remained in stroke patients.
  
  
  CONCLUSIONS
  In patients with TIA and completed stroke, platelet and leukocyte activation is substantially enhanced in the acute phase of the disease. The sustained leukocyte activation observed in stroke but not in TIA patients at 3-month follow up might play a pathophysiological role in the course of the disease.
authors.affiliation: Medizinische Klinik mit Schwerpunkt Nephrologie und Intensivmedizin, Charité-Campus Virchow-Klinikum, Universitätsmedizin Berlin, Humboldt-Universität zu Berlin, Germany. p.htun@web.de
authors.forename: Patrik
authors.initials: P
authors.lastname: Htun
authors.forename: Suzanne
authors.initials: S
authors.lastname: Fateh-Moghadam
authors.forename: Bernd
authors.initials: B
authors.lastname: Tomandl
authors.forename: René
authors.initials: R
authors.lastname: Handschu
authors.forename: Kathrin
authors.initials: K
authors.lastname: Klinger
authors.forename: Konstantinos
authors.initials: K
authors.lastname: Stellos
authors.forename: Christoph
authors.initials: C
authors.lastname: Garlichs
authors.forename: Werner
authors.initials: W
authors.lastname: Daniel
authors.forename: Meinrad
authors.initials: M
authors.lastname: Gawaz
mesh_terms: D000368:Aged; D001792:Blood Platelets / Q000378:metabolism; D002449:Cell Aggregation; D002450:Cell Communication; D005260:Female; D006801:Humans; D002546:Ischemic Attack, Transient / Q000097:blood*; D019041:L-Selectin / Q000097:blood; D007962:Leukocytes / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D019007:P-Selectin / Q000097:blood / Q000378:metabolism; D015539:Platelet Activation; D020521:Stroke / Q000097:blood*; D013997:Time Factors
chemical_list: D019007:P-Selectin; D019041:L-Selectin