title: Expression and function of purinergic receptors in platelets from apheresis-derived platelet concentrates.
abstract: BACKGROUND
  The storage of platelets affects platelet integrity and functionality, a process named platelet storage lesion (PSL). Reduced adenosine diphosphate (ADP)-induced platelet aggregation is a typical manifestation of PSL. However, the role of ADP receptors in this context has not been evaluated yet. The aim of this study was, therefore, to investigate surface expression and function of the purinergic receptors P2Y1, P2Y12 and P2X1 in stored platelet concentrates.
  
  
  METHODS
  Platelets were obtained from venous whole blood and from apheresis-derived platelet concentrates stored for 0, 2 and 5 days. Purinergic receptor expression was measured by flow cytometry and western blot analysis. Receptor function was determined by calcium-induced fluorescence (P2Y1 and P2X1) or by flow cytometric measurement of the platelet reactivity index (P2Y12).
  
  
  RESULTS
  The basal surface expression and total content of purinergic receptors remained unchanged throughout storage. After an initial reduction during apheresis, P2X1-mediated calcium flux was maintained, whereas the P2Y1-mediated increase of calcium flux gradually decreased during the course of storage. In contrast, the platelet reactivity index was comparable in freshly obtained and stored platelets.
  
  
  CONCLUSIONS
  The function of the P2Y12 receptor is maintained during storage of apheresis-derived platelet concentrates. However, the impairment of P2X1 and especially of P2Y1 receptor function indicated by decreased receptor-mediated calcium flux is an important mechanism contributing to reduced ADP responsiveness of stored platelets.
authors.affiliation: Institute of Transfusion Medicine and Haemotherapy, University of Würzburg, Würzburg, Germany.
authors.forename: Juergen
authors.initials: J
authors.lastname: Koessler
authors.affiliation: Institute of Transfusion Medicine and Haemotherapy, University of Würzburg, Würzburg, Germany.
authors.forename: Katja
authors.initials: K
authors.lastname: Weber
authors.affiliation: Institute of Transfusion Medicine and Haemotherapy, University of Würzburg, Würzburg, Germany.
authors.forename: Angela
authors.initials: A
authors.lastname: Koessler
authors.affiliation: Institute of Transfusion Medicine and Haemotherapy, University of Würzburg, Würzburg, Germany.
authors.forename: Pinar
authors.initials: P
authors.lastname: Yilmaz
authors.affiliation: Institute of Transfusion Medicine and Haemotherapy, University of Würzburg, Würzburg, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Boeck
authors.affiliation: Institute of Transfusion Medicine and Haemotherapy, University of Würzburg, Würzburg, Germany.
authors.forename: Anna
authors.initials: A
authors.lastname: Kobsar