PLATELET SIZE DOES NOT CORRELATE WITH PLATELET AGE

  • 1 January 1983
    • journal article
    • research article
    • Vol. 62  (2) , 487-494
Abstract
The relationship between platelet size and in vivo aging was investigated in the baboon using size-dependent platelet subpopulations separated by counterflow centrifugation. The separation characteristics, size, lactate dehydrogenase (LDH) activity, and dense-body content of the baboon platelet subpopulations were similar to those previously observed in studies of human platelets. Three independent labeling techniques were used: in vivo labeling with 75Se-methionine, in vitro labeling with 51Cr and in vivo labeling with 14C-serotonin. Maximal incorporation of all 3 labels showed a close correlation between the mean platelet volume (MPV) of each fraciton and the platelet radioactivity. The onset of incorporation and rate of accumulation of 75Se-methionine were comparable in all fractions when corrected for differences in volume, suggesting that platelet size heterogeneity was present from the time of release of the platelets from the bone marrow. Survival studies using 51Cr and 14C-serotonin showed no translocation of the label from 1 fraction to another in the circulation over time. In vivo survival values for the 3 radionuclides showed a slight but significant correlation between the lifespan and the MPV of the fractions. Large platelets apparently were not younger platelets, but rather platelets with a longer life span. Platelet size heterogeneity is the result of production factors in the bone marrow and not maturation in the circulation.