title: Storage of platelets in additive solutions: effects of magnesium and/or potassium.
abstract: BACKGROUND
  Previous studies indicate that platelet concentrates (PCs) in a platelet additive solution (PAS) containing citrate, acetate, and sodium chloride (PAS-2) show a significantly higher increase of CD62+ platelets than PCs in other brands of PAS containing Mg(2+) and K(+). To investigate whether this difference can be explained by the presence of Mg(2+) and/or K(+) in the storage medium, we performed paired studies comparing storage of PCs in PAS-2 to PAS-2 with either Mg(2+) or K(+) or both in combination.
  
  
  METHODS
  PCs from pooled buffy coats were prepared in either PAS-2 or PAS-2 with Mg(2+) or K(+) or both in combination (PAS-2 modified). Different volumes of MgCl(2) solution (1 mol/L) and/or KCl solution (1 mol/L) were added to PAS-2 to obtain various concentrations. After preparation and during storage (at Days 3 and 7), pH, pCO(2), pO(2), HCO(3)(-), and CD62 (%) were measured.
  
  
  RESULTS
  During 7 days of storage, pH was very stable (6.9-7.2) in all PCs. At Day 7, platelet CD62 expression was 49 percent (PAS-2), 41 percent (PAS-2 with 1.5 mmol/L Mg(2+)), and 38 percent (PAS-2 with 4.5 mmol/L Mg(2+)). With added K(+), at Day 7, expression of CD62 was 55 percent (PAS-2), 39 percent (PAS-2 with 4.5 mmol/L K(+)), and 35 percent (PAS-2 with 9.0 mmol/L K(+)). In PAS-2 modified (PAS-2 with 1.5 mmol/L Mg(2+) and 4.5 mmol/L K(+)) and CPD plasma, the corresponding CD62 values were 23 and 35 percent, respectively.
  
  
  CONCLUSIONS
  The combination of Mg(2+) and K(+) gave significantly (p < 0.05) lower platelet CD62 expression in the storage medium than in PAS-2. The effects of these differences on platelet metabolism and in vivo properties remain to be investigated.
authors.affiliation: Sanquin Bloodbank Ijssellanden, BR Zwolle, The Netherlands. jdewildt@bloedbankijsellanden.nl
authors.forename: Janny
authors.initials: J
authors.lastname: de Wildt-Eggen
authors.forename: Johanna G
authors.initials: JG
authors.lastname: Schrijver
authors.forename: Maarten
authors.initials: M
authors.lastname: Bins
authors.forename: Hans
authors.initials: H
authors.lastname: Gulliksson
mesh_terms: D000085:Acetates / Q000737:chemistry / Q000494:pharmacology*; D001792:Blood Platelets / Q000187:drug effects*; D001793:Blood Preservation; D002951:Citrates / Q000737:chemistry / Q000494:pharmacology*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D015636:Magnesium Chloride / Q000494:pharmacology*; D009994:Osmolar Concentration; D019007:P-Selectin / Q000032:analysis; D010949:Plasma; D015539:Platelet Activation / Q000187:drug effects; D011189:Potassium Chloride / Q000494:pharmacology*; D012965:Sodium Chloride / Q000737:chemistry / Q000494:pharmacology*; D012996:Solutions / Q000494:pharmacology*
chemical_list: D000085:Acetates; D002951:Citrates; D019007:P-Selectin; C436265:PAS-2 salt solution; D012996:Solutions; D015636:Magnesium Chloride; D012965:Sodium Chloride; D011189:Potassium Chloride