Effect of age on hematopoiesis in man
DA Lipschitz, KB Udupa, KY Milton and CO Thompson
We have shown previously that the cause of anemia in healthy elderly
subjects can usually not be identified. In this study, hematopoiesis was
examined in 18 healthy elderly subjects with unexplained anemia and in 15
young and 15 healthy elderly individuals without anemia. No reduction in
circulating testosterone was noted, making decreased androgen levels as a
cause for the anemia unlikely. The 2,3 diphospho- glycerate (2,3DPG) levels
in the anemic subjects were significantly higher than their corresponding
controls, suggesting that the anemia was pathologic, as no increase would
be expected if the low hemoglobin was a physiologic adjustment to age. The
anemia was associated with a reduction in marrow normoblast and CFU-E
number, but no decrease in BFU- E levels was seen. This suggests that the
mechanism of the anemia is a decrease in stem cell proliferation. This
could be caused by a reduction in circulating erythropoietin or a defect in
end organ response. A second possibility is that a basic cellular
abnormality exists. The presence of an overall reduction in hematopoiesis
in anemic elderly (decreased peripheral blood counts, reduced marrow
myeloid precursors, and CFU-C levels) makes this especially likely. The
abnormality may be caused by a mechanism unrelated to the aging process.
The fact that nonanemic elderly also have reductions in hematopoiesis
suggests that age contributes to the defect.
Volume 63,
Issue 3,
pp. 502-509,
03/01/1984
Copyright © 1984 by The American Society of Hematology
