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Blood, 16 July 2009, Vol. 114, No. 3, pp. 723-732. Prepublished online as a Blood First Edition Paper on April 15, 2009; DOI 10.1182/blood-2009-02-205930. This Article Full Text Full Text (PDF) Supplemental Tables All Versions of this Article: blood-2009-02-205930v1 114/3/723    most recent Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Rights and Permissions Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Google Scholar Articles by Prokopi, M. Articles by Mayr, M. PubMed PubMed Citation Articles by Prokopi, M. Articles by Mayr, M. Related Collections Platelets and Thrombopoiesis Vascular Biology Related Article in Blood Online Social Bookmarking                   What's this?  Previous Article  |  Table of Contents  |  Next Article  VASCULAR BIOLOGY Proteomic analysis reveals presence of platelet microparticles in endothelial progenitor cell cultures Marianna Prokopi1, Giordano Pula1, Ursula Mayr1, Cécile Devue2, Joy Gallagher3, Qingzhong Xiao1, Chantal M. Boulanger2, Nigel Westwood4, Carmen Urbich5, Johann Willeit6, Marianne Steiner7, Johannes Breuss8, Qingbo Xu1, Stefan Kiechl6, and Manuel Mayr1 1 King's British Heart Foundation Centre, King's College London, London, United Kingdom; 2 Paris-Cardiovascular Research Center, Inserm U970, Hôpital Européen Georges Pompidou, Université Paris-Descartes, Paris, France; 3 King's College Hospital, National Health Service (NHS) Foundation Trust, Blood Sciences Laboratory Services, London, United Kingdom; 4 Department of Haematological Medicine, King's College London, London, United Kingdom; 5 Molecular Cardiology, Department of Medicine III, University of Frankfurt, Frankfurt, Germany; 6 Department of Neurology, Medical University Innsbruck, Innsbruck, Austria; 7 Center for Anatomy and Cell Biology, Medical University Vienna, Vienna, Austria; and 8 Department of Vascular Biology and Thrombosis Research, Centre for Bio-Molecular Medicine and Pharmacology, Medical University of Vienna, Vienna, Austria The concept of endothelial progenitor cells (EPCs) has attracted considerable interest in cardiovascular research, but despite a decade of research there are still no specific markers for EPCs and results from clinical trials remain controversial. Using liquid chromatography–tandem mass spectrometry, we analyzed the protein composition of microparticles (MPs) originating from the cell surface of EPC cultures. Our data revealed that the conventional methods for isolating mononuclear cells lead to a contamination with platelet proteins. Notably, platelets readily disintegrate into platelet MPs. These platelet MPs are taken up by the mononuclear cell population, which acquires "endothelial" characteristics (CD31, von Willebrand factor [VWF], lectin-binding), and angiogenic properties. In a large population-based study (n = 526), platelets emerged as a positive predictor for the number of colony-forming units and early outgrowth EPCs. Our study provides the first evidence that the cell type consistent with current definitions of an EPC phenotype may arise from an uptake of platelet MPs by mononuclear cells resulting in a gross misinterpretation of their cellular progeny. These findings demonstrate the advantage of using an unbiased proteomic approach to assess cellular phenotypes and advise caution in attributing the benefits in clinical trials using unselected bone marrow mononuclear cells (BMCs) to stem cell-mediated repair. CiteULike    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this? Related Article in Blood Online: Platelet MPs obscure some EPC definitions Mervin C. Yoder Blood 2009 114: 495-496. [Full Text] [PDF] This article has been cited by other articles: M. C. Yoder Platelet MPs obscure some EPC definitions Blood, July 16, 2009; 114(3): 495 - 496. [Full Text] [PDF]

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