Red blood cell (RBC) survival determined in humans using RBCs labeled at multiple biotin densities.
BACKGROUND
Safe, accurate methods permitting simultaneous and/or repeated measurement of red blood cell (RBC) survival (RCS) are important to investigate pathophysiology and therapy of anemia. Methods using chromium 51 ((51) Cr)-labeled RBCs are unacceptable for infants, children, and pregnant women. We report RCS measured in vivo using RBCs labeled with several densities of biotin (BioRBCs).


METHODS
Aliquots of autologous RBCs from eight healthy adult subjects were labeled separately at four discrete biotin densities, mixed, and infused. The proportion of each population of BioRBCs circulating was determined serially by flow cytometry over 20 weeks. For each population, RCS was assessed by the following: 1) posttransfusion BioRBC recovery at 24 hours (PTR(24) ); 2) time to decrease to 50% of the enrichment at 24 hours (T(50) ); and 3) mean potential lifespan (MPL).


RESULTS
Among the four BioRBC densities, no significant differences in PTR(24) were observed. T(50) and MPL were similar for the two lowest BioRBC densities. In contrast, the two highest BioRBC densities demonstrated progressively decreased T(50) and MPL.


CONCLUSIONS
RBCs labeled at four biotin densities can be used to independently and accurately measure PTR(24 ) and two lowest biotin densities can accurately quantitate long-term RCS. This method provides a tool for investigating anemia in infants, fetuses, and pregnant women with the following advantages over the standard (51) Cr method: 1) study subjects are not exposed to radiation; 2) small blood volumes (e.g., 20 µL) are required; and 3) multiple independent RCS measurements can be made simultaneously in the same individual.
Department of Biochemistry & Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205, USA. mockdonaldm@uams.edu
Donald M
DM
Mock
Nell I
NI
Matthews
Shan
S
Zhu
Ronald G
RG
Strauss
Robert L
RL
Schmidt
Demet
D
Nalbant
Gretchen A
GA
Cress
John A
JA
Widness
D000328:Adult; D000906:Antibodies / Q000097:blood; D001710:Biotin / Q000276:immunology / Q000378:metabolism*; D019921:Biotinylation / Q000379:methods*; D002470:Cell Survival / Q000502:physiology; D017707:Erythrocyte Transfusion / Q000592:standards*; D004912:Erythrocytes / Q000166:cytology* / Q000276:immunology / Q000378:metabolism; D005260:Female; D005434:Flow Cytometry / Q000379:methods* / Q000592:standards; D006242:Haptoglobins / Q000378:metabolism; D006461:Hemolysis; D006801:Humans; D008297:Male; D008875:Middle Aged; D012015:Reference Standards; D013194:Staining and Labeling / Q000379:methods; D055815:Young Adult
D000906:Antibodies; D006242:Haptoglobins; D001710:Biotin