title: Dynamic release and clearance of circulating microparticles during cardiac stress.
abstract: BACKGROUND
  Microparticles are cell-derived membrane vesicles, relevant to a range of biological responses and known to be elevated in cardiovascular disease.
  
  
  OBJECTIVE
  To investigate microparticle release during cardiac stress and how this response differs in those with vascular disease.
  
  
  RESULTS
  We measured a comprehensive panel of circulating cell-derived microparticles by a standardized flow cytometric protocol in 119 patients referred for stress echocardiography. Procoagulant, platelet, erythrocyte, and endothelial but not leukocyte, granulocyte, or monocyte-derived microparticles were elevated immediately after a standardized dobutamine stress echocardiogram and decreased after 1 hour. Twenty-five patients developed stress-induced wall motion abnormalities suggestive of myocardial ischemia. They had similar baseline microparticle levels to those who did not develop ischemia, but, interestingly, their microparticle levels did not change during stress. Furthermore, no stress-induced increase was observed in those without inducible ischemia but with a history of vascular disease. Fourteen patients subsequently underwent coronary angiography. A microparticle rise during stress echocardiography had occurred only in those with normal coronary arteries.
  
  
  CONCLUSIONS
  Procoagulant, platelet, erythrocyte, and endothelial microparticles are released during cardiac stress and then clear from the circulation during the next hour. This stress-induced rise seems to be a normal physiological response that is diminished in those with vascular disease.
authors.affiliation: From the Oxford Cardiovascular Clinical Research Facility, University of Oxford, Oxford, United Kingdom (D.A., E.L., L.N., A.J.L., E.F.D., P.L.); and Department of Clinical Immunology, Oxford University Hospitals NHS Trust, Oxford, United Kingdom (L.V.A., B.F.).
authors.forename: Daniel
authors.initials: D
authors.lastname: Augustine
authors.forename: Lisa V
authors.initials: LV
authors.lastname: Ayers
authors.forename: Eduardo
authors.initials: E
authors.lastname: Lima
authors.forename: Laura
authors.initials: L
authors.lastname: Newton
authors.forename: Adam J
authors.initials: AJ
authors.lastname: Lewandowski
authors.forename: Esther F
authors.initials: EF
authors.lastname: Davis
authors.forename: Berne
authors.initials: B
authors.lastname: Ferry
authors.forename: Paul
authors.initials: P
authors.lastname: Leeson
mesh_terms: D000328:Adult; D000368:Aged; D001792:Blood Platelets / Q000473:pathology; D055252:Cell-Derived Microparticles / Q000145:classification / Q000473:pathology*; D017023:Coronary Angiography; D003331:Coronary Vessels / Q000473:pathology / Q000503:physiopathology; D003937:Diagnosis, Differential; D004280:Dobutamine; D004452:Echocardiography; D042783:Endothelial Cells / Q000473:pathology; D004912:Erythrocytes / Q000473:pathology; D005080:Exercise Test; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000097:blood* / Q000175:diagnosis / Q000473:pathology; D013312:Stress, Physiological; D014652:Vascular Diseases / Q000097:blood / Q000175:diagnosis / Q000473:pathology
chemical_list: D004280:Dobutamine
keywords: dobutamine stress echocardiography; microparticles, cell-derived; vascular diseases