Ultrastructural changes and activation differences in platelet concentrates stored in plasma and additive solution.
BACKGROUND
The aim of this study was to demonstrate how ultrastructural morphology of platelets stored in different media correlate with the appearance of particular activation markers on their cell surface.


METHODS
Concentrates of buffy coat-derived platelets were stored in plasma or a glucose-free citrate-acetate-NaCl platelet additive solution (PAS2, Baxter Healthcare Corp.). Activation markers on platelets were measured by flow cytometry and compared with changes in the platelet cell surface as demonstrated by electron microscopy. Levels of the vasoactive cytokines vascular endothelial growth factor (VEGF) and RANTES (regulated upon activation, normal T-cell expressed and secreted) were determined in the storage medium of the platelet concentrate.


RESULTS
The activation markers CD62P and CD63 and the binding of thrombospondin measured by flow cytometry were expressed to a higher extent in the PAS2 group compared with the plasma group. The difference reached significance on Day 3 (CD62P: 66.37 +/- 2.44 vs. 37.83 +/- 2.03, p < 0.001; CD63: 42.11 +/- 3.29 vs. 34.84 +/- 2.04, p < 0.05; and thrombospondin binding: 18.84 +/- 3.9 vs. 13.98 +/- 3.87, p < 0.001, respectively). The form factor that is related to changes of the platelet shape was determined by image analysis and correlated significantly with the cell surface expression of CD62P (p < 0.001) and with CD63 (p < 0.05) and with thrombospondin binding (p < 0.05). The chemokines VEGF and RANTES were measured at higher levels in the PAS2 group.


CONCLUSIONS
With exception of baseline activation probably due to necessary handling procedures, platelets remain relatively unaltered and more stable in plasma in comparison to storage in PAS2.
Wagner
Thomas
T
Department of Blood Group Serology and Transfusion Medicine, Graz, Austria.
Vetter
Angelika
A
Dimovic
Natascha
N
Guber
S E
SE
Helmberg
Wolfgang
W
Kröll
Wolfgang
W
Lanzer
Gerhard
G
Mayr
W R
WR
Neumüller
Josef
J
D000085:Acetates / Q000494:pharmacology; D000328:Adult; D016824:Antigens, Human Platelet / Q000032:analysis; D001792:Blood Platelets / Q000187:drug effects* / Q000648:ultrastructure; D001793:Blood Preservation / Q000379:methods*; D002470:Cell Survival; D018946:Chemokine CCL5 / Q000032:analysis; D002951:Citrates / Q000494:pharmacology; D017077:Culture Media, Conditioned / Q000737:chemistry; D016228:Endothelial Growth Factors / Q000032:analysis; D005434:Flow Cytometry; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008222:Lymphokines / Q000032:analysis; D008855:Microscopy, Electron, Scanning; D010949:Plasma; D015539:Platelet Activation / Q000187:drug effects*; D012965:Sodium Chloride / Q000494:pharmacology; D012996:Solutions; D019699:Thrombospondins / Q000032:analysis; D013997:Time Factors; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors
D000085:Acetates; D016824:Antigens, Human Platelet; D018946:Chemokine CCL5; D002951:Citrates; D017077:Culture Media, Conditioned; D016228:Endothelial Growth Factors; D008222:Lymphokines; D012996:Solutions; D019699:Thrombospondins; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; D012965:Sodium Chloride