Changes in Band 3 oligomeric state precede cell membrane phospholipid loss during blood bank storage of red blood cells.
BACKGROUND
Lipid loss in the form of vesicles contributes to the red blood cell (RBC) storage lesion, and this loss of lipid is correlated with changes in membrane protein function. Sensitive spectroscopic techniques were used to measure changes in Band 3 oligomeric state during storage of RBCs, compared to metabolic changes and phospholipid loss. The aim of the study was to determine whether changes in the macromolecular organization of membrane proteins occur before, coincident with, or after lipid loss during RBC storage.


METHODS
Five RBC units were collected from normal volunteers and stored under standard blood bank conditions, and both metabolic changes and lipid loss were measured by multiple assays. Band 3 oligomeric state was assessed by time-resolved phosphorescence anisotropy and fluorescence resonance energy transfer of eosin-5-maleimide-labeled RBC ghosts.


RESULTS
Extracellular pH decreased and extracellular potassium increased rapidly during cold storage of blood. Band 3 on the RBC membrane exhibited a shift from small to large oligomers early in the storage period and before detectable loss of phospholipid from the RBC membrane. The immobilized fraction of Band 3, that which is tethered to the cytoskeletal network via spectrin and ankyrin, did not change during cold storage.


CONCLUSIONS
Our results demonstrate that changes in the macromolecular organization of membrane proteins on the RBC occur early in storage, and these changes may induce phospholipid loss, irreversible morphologic changes, and loss of function during RBC storage.
Karon
Brad S
BS
Department of Laboratory Medicine and Pathology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA.
Hoyer
James D
JD
Stubbs
James R
JR
Thomas
David D
DD
D001771:Blood Banks; D001793:Blood Preservation / Q000009:adverse effects*; D004912:Erythrocytes / Q000378:metabolism*; D006801:Humans; D010743:Phospholipids / Q000378:metabolism*
D010743:Phospholipids