title: Responsiveness of platelets during storage studied with flow cytometry--formation of platelet subpopulations and LAMP-1 as new markers for the platelet storage lesion.
abstract: OBJECTIVE
  Storage lesions may prevent transfused platelets to respond to agonists and arrest bleeding. The aim of this study was to evaluate and quantify the capacity of platelet activation during storage using flow cytometry and new markers of platelet activation.
  
  
  METHODS
  Activation responses of platelets prepared by apheresis were measured on days 1, 5, 7 and 12. In addition, comparisons were made for platelet concentrates stored until swirling was affected. Lysosome-associated membrane protein-1 (LAMP-1), P-selectin and phosphatidylserine (PS) exposure were assessed by flow cytometry on platelets in different subpopulations in resting state or following stimulation with platelet agonists (cross-linked collagen-related peptide (CRP-XL), PAR1- and PAR4-activating peptides).
  
  
  RESULTS
  The ability to form subpopulations upon activation was significantly decreased already at day 5 for some agonist combinations. The agonist-induced exposure of PS and LAMP-1 also gradually decreased with time. Spontaneous exposure of P-selectin and PS increased with time, while spontaneous LAMP-1 exposure was unchanged. In addition, agonist-induced LAMP-1 expression clearly discriminated platelet concentrates with reduced swirling from those with retained swirling. This suggests that LAMP-1 could be a good marker to capture changes in activation capacity in stored platelets.
  
  
  CONCLUSIONS
  The platelet activation potential seen as LAMP-1 exposure and fragmentation into platelet subpopulations is potential sensitive markers for the platelet storage lesion.
authors.affiliation: Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden.
authors.forename: A L
authors.identifier: http://orcid.org/0000-0003-0460-4744
authors.initials: AL
authors.lastname: Södergren
authors.affiliation: Department of Clinical Immunology and Transfusion Medicine, and Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden.|Department of Clinical Chemistry and Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden.
authors.forename: N
authors.initials: N
authors.lastname: Tynngård
authors.affiliation: Department of Clinical Immunology and Transfusion Medicine, and Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden.
authors.forename: G
authors.initials: G
authors.lastname: Berlin
authors.affiliation: Department of Clinical and Experimental Medicine, Linköping University, Linköping, Sweden.
authors.forename: S
authors.initials: S
authors.lastname: Ramström
mesh_terms: D015415:Biomarkers / Q000097:blood; D001792:Blood Platelets / Q000166:cytology* / Q000378:metabolism; D001793:Blood Preservation / Q000009:adverse effects*; D005434:Flow Cytometry; D006801:Humans; D052118:Lysosomal-Associated Membrane Protein 1 / Q000097:blood*; D015539:Platelet Activation
chemical_list: D015415:Biomarkers; D052118:Lysosomal-Associated Membrane Protein 1
keywords: apheresis; haemostasis; platelet concentrates; platelet function; platelet transfusion