Effect of heating on extracellular bioactive substances in stored human blood: in vitro study

We have previously shown extracellular accumulation of various leukocyte and platelet-derived bioactive substances in human blood during storage. Release of bioactive substances may be temperature-dependent, and we studied the effect of heating during in vitro transfusion on bioactive substance accumulation in stored human blood.

Eight units of whole blood and eight units of prestorage leukofiltered whole blood were stored at 4 degrees C for 7 days. Subsequently, the blood from all 16 units was transfused via a blood-heating device, which increased the blood temperature to 37 degrees C at outlet. Samples for enzyme-linked immunosorbent assay or radioimmunoassay analyses of histamine, myeloperoxidase (MPO), eosinophil cationic protein (ECP), and plasminogen activator inhibitor-1 (PAI-1) were drawn from the units at donation, after 7 days of storage just before transfusion, and during the in vitro transfusion.

Extracellular concentrations of histamine, MPO, ECP, and PAI-1 were significantly (p < 0.05) increased in nonfiltered whole blood stored for 7 days compared with concentrations in fresh donated blood and in prestorage leukofiltered whole blood stored for 7 days. Heating reduced histamine, MPO, and ECP concentrations significantly (p < 0.05) in nonfiltered whole blood, whereas PAI-1 concentrations increased significantly (p < 0.05). Finally, there was no difference in concentrations of histamine, MPO, ECP, and PAI-1 in samples collected before and after heating of leukofiltered whole blood.

Heating reduces accumulation of extracellular leukocyte-derived bioactive substances in whole blood, whereas it increases platelet-derived substances. Prestorage leukofiltration, however, reduces the obligatory extracellular accumulation of leukocyte and platelet-derived bioactive substances, which in addition is unchanged by heating.