title: Six hours of resting platelet concentrates stored at 22-24 ºC for 48 hours in permeable bags preserved pH, swirling and lactate dehydrogenase better and caused less platelet activation.
abstract: BACKGROUND
  During transportation, platelet concentrates (PC) usually undergo a long period without agitation. Whether this interruption improves quality and viability or, contrariwise, has deleterious effects on PC stored for 48 hours (h) is unknown. The aim of this study was to investigate the effects of metabolic resting (6 h of interruption of agitation) vs continue agitation of PC stored for 48 h in the blood bank of Tehran.
  
  
  METHODS
  PC were prepared from platelet-rich plasma and stored in permeable bags in a shaker/incubator for 42 h at room temperature (20-24 ºC). Then, simply by stopping the agitator, the PC remained stationary ("resting") without agitation for 6 h (WCA6h), prior to transfusion. In vitro measurements of platelet quality were carried out just after completion of the resting period and the results were compared with those of PC continuously agitated in the same day (designated as the control group, CA6h). The in vitro variables measured were swirling, ristocetin-induced aggregation (GPIb-related function), lactate dehydrogenase (LDH) concentration, platelet factor 4 (PF4) release and P-selectin expression (activation markers).
  
  
  RESULTS
  The mean platelet counts of the control group (CA6h) and rested (WCA6h) PC were not statistically different (P =0.548). Likewise, the mean pH values were not significantly different: WCA6h (7.16 ± 0.08) and CA6h (7.22 ± 0.16) (P =0.300). Although ristocetin-induced aggregation did not differ significantly between CA6h (79.2 ± 4.4) and WCA6h (66.65 ± 28.55) (P =0.186), WCA6h showed significantly less PFA release (P =0.015) and lower P-selectin expression (P =0.006).
  
  
  CONCLUSIONS
  We observed that PC stored under agitation for 42 h at 22-24 ºC in permeable bags and then rested for 6 h had better preserved pH, swirling and LDH and less platelet activation then PC kept under continuous agitation for the whole 48 h storage period.
authors.affiliation: Blood Transfusion Research Centre, Higher Institute for Research and Education in Transfusion Medicine, IBTO, Tehran, Iran. timori13@gmail.com
authors.forename: Hossin T
authors.initials: HT
authors.lastname: Naghadeh
authors.forename: Bahram A
authors.initials: BA
authors.lastname: Badlou
authors.forename: Ali S
authors.initials: AS
authors.lastname: Ferizhandy
authors.forename: Tabatabai S
authors.initials: TS
authors.lastname: Mohammadreza
authors.forename: Vaeli
authors.initials: V
authors.lastname: Shahram
mesh_terms: D001792:Blood Platelets / Q000166:cytology / Q000378:metabolism*; D001793:Blood Preservation; D005260:Female; D006358:Hot Temperature; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007770:L-Lactate Dehydrogenase / Q000378:metabolism*; D008297:Male; D019007:P-Selectin / Q000378:metabolism*; D015539:Platelet Activation; D010978:Platelet Factor 4 / Q000378:metabolism*; D012310:Ristocetin / Q000494:pharmacology; D013997:Time Factors
chemical_list: D019007:P-Selectin; D012310:Ristocetin; D010978:Platelet Factor 4; D007770:L-Lactate Dehydrogenase