Erythropoietin induces the expansion of c‐kit+ progenitors for myeloid and erythroid cells, but not for lymphoid cells, in the bone marrow and liver

Abstract

In humans, the numbers of erythrocytes and granulocytes, but not that of lymphocytes, tend to increase in parallel. To determine the mechanism, we investigated how the administration of erythropoietin induces the expansion of erythroid cells and other lineage cells in the bone marrow, liver, and other organs of mice. When mice were injected twice (days 1 and 2) with erythropoietin at a dose of 20 or 200 IU/day/mouse, a prominent expansion of TER119+ (erythroid cells) and Gr‐1high cells (granulocytes) occurred in the liver, spleen, and bone marrow day 3 after the initial injection. On the other hand, lymphoid cells, including NK cells, extrathymic T cells, and conventional T cells, did not expand. In parallel with the expansion of erythroid cells and granulocytes, the levels of c‐kit+Lin− cells increased in the liver and bone marrow. Despite the increase in the proportion of c‐kit +Lin− cells, the generation of lymphocytes (e.g., T cells) decreased when such bone marrow cells were injected to scid mice. These results suggest that erythropoietin has the ability to induce the expansion of not only erythroid cells but also granulocytes in the liver, spleen, and bone marrow. Furthermore, c‐kit+ progenitors which may commit themselves to erythroid and myeloid cells, but not to lymphoid cells, were also activated in the liver and bone marrow of mice treated with erythropoietin.

Haemopoietic System of the Anurans: The Role of Bone Marrow and Liver

“…Thus, we can assume that the liver of anurans along with their bone marrow may be a donor of the erythroblasts and basophilic normoblasts, which continue to differentiation and proliferation in the vascular bed. This conclusion coincides with the most recent data in literature (Thomas, Maclean, 1975;Chegini et al, 1979;Maslova, Tavrovsky, 1993;Koya et al, 1999;Nogawa-Kosaka et al, 2011). Comparing the coefficients of variation, we can also conclude that the individual variability in the intensity of erythropoiesis in the liver in the spring and summer is more prominent than in the bone marrow, although in the summer this difference is weak.…”

“…However, peculiarity of the heamatopoiesis outside the bone marrow cavity in adult amphibians representatives have not been studied enough. In particular, there are indications that hematopoiesis in the liver of anurans exists in adult animals (Spornitz, 1975;Thomas, Maclean, 1975;Koya et al, 1999;Nogawa-Kosaka et al, 2011) while there is a research denying this argument (de Abreu et al, 2009).…”