Changes in Proteasome Concentrations in Whole Blood and Packed Red Blood Cell Units during Storage

Kim, Yu Kyung; Suh, Jang Soo

Abstract

BACKGROUND
Proteasomes are multi-subunit enzyme complexes present in the cytoplasm and nucleus of eukaryotic cells. Proteasomes are involved in the pathophysiological process resulting in development of many diseases. Release of proteasomes from lyzed erythrocytes has been suggested in recent reports. Accumulation of proteasomes in blood products could contribute to formation of storage lesions and have adverse effects on recipients; therefore, we conducted an analysis of changes in concentration of proteasomes in blood products during storage.
METHODS
Concentrations of 20S proteasomes in supernatant of whole blood products obtained from eight healthy volunteers and in segments of 16 packed red blood cell (pRBC) units transfused to patients were measured by ELISA. Plasma samples containing several hemoglobin concentrations were prepared in order to assess the relationship between proteasome concentration and degree of hemolysis.
RESULTS
Proteasome concentrations in whole blood products on day one of storage were significantly lower than those on day seven of storage and later (P<0.05). In segments of pRBC units, the proteasome concentration was 8.072+/-11.802 microg/mL (storage day: 13.8+/-4.7). Of the 32 pRBC units, two showed extremely high proteasome concentrations (36.662 and 62.798 microg/mL). Proteasome concentrations in plasma increased with increasing hemoglobin concentrations.
CONCLUSION
During storage of whole blood products, except during the first seven storage days, levels of proteasome do not undergo significant change. However, hemolysis may be related to accumulation of proteasome. Further study to evaluate the effects of blood components containing high proteasome concentrations on recipients should be conducted.