title: Temporal sequence of major biochemical events during blood bank storage of packed red blood cells.
abstract: BACKGROUND
  We used sensitive spectroscopic techniques to measure changes in Band 3 oligomeric state during storage of packed red blood cells (RBC); these changes were compared to metabolic changes, RBC morphology, cholesterol and membrane protein loss, phospholipid reorganisation of the RBC membrane, and peroxidation of membrane lipid. The aim of the study was to temporally sequence major biochemical events occurring during cold storage, in order to determine which changes may underlie the structural defects in stored RBC.
  
  
  METHODS
  Fifteen RBC units were collected from normal volunteers and stored under standard blood bank conditions; both metabolic changes and lipid parameters were measured by multiple novel assays including a new mass spectrometric measurement of isoprostane (lipid peroxidation) and flow cytometric assessment of CD47 expression. Band 3 oligomeric state was assessed by time-resolved phosphorescence anisotropy, and RBC morphology by microscopy of glutaraldehyde-fixed RBC.
  
  
  RESULTS
  Extracellular pH decreased and extracellular potassium increased rapidly during cold storage. Band 3 on the RBC membrane aggregated into large oligomers early in the storage period and coincident with changes in RBC morphology. Membrane lipid changes, including loss of unesterified cholesterol, lipid peroxidation and expression of CD47, also changed early during the storage period. In contrast loss of acetylcholinesterase activity and haemolysis of RBC occurred late during storage.
  
  
  CONCLUSIONS
  Our results demonstrate that changes in the macromolecular organisation of membrane proteins on the RBC occur early in storage and suggest that lipid peroxidation and/or oxidative damage to the membrane are responsible for irreversible morphological changes and loss of function during red cell storage.
authors.affiliation: Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota 55455, USA.
authors.forename: Brad S
authors.initials: BS
authors.lastname: Karon
authors.forename: Camille M
authors.initials: CM
authors.lastname: van Buskirk
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Jaben
authors.forename: James D
authors.initials: JD
authors.lastname: Hoyer
authors.forename: David D
authors.initials: DD
authors.lastname: Thomas
mesh_terms: D001457:Anion Exchange Protein 1, Erythrocyte / Q000378:metabolism*; D001771:Blood Banks; D001793:Blood Preservation; D051928:CD47 Antigen / Q000096:biosynthesis*; D004910:Erythrocyte Membrane / Q000378:metabolism*; D005260:Female; D005786:Gene Expression Regulation; D006801:Humans; D006863:Hydrogen-Ion Concentration; D015227:Lipid Peroxidation; D008297:Male
chemical_list: D001457:Anion Exchange Protein 1, Erythrocyte; D051928:CD47 Antigen; C497894:CD47 protein, human; C454201:SLC4A1 protein, human