Ontogenic variations of cytokines

Abstract

We have previously shown that fetal stem cells derived from miscarriages exhibit high efficiency for transplantation. We reported that fetal bone marrow (FBM) has a higher number of CD34 cells, greater clonogenic capacity and lowered immunologic reactivity than adult bone marrow (ABM), cord blood (CB), and peripheral blood (PBSC). The present studies were designed to investigate whether similar ontogenic differences exist in the expression of cytokine in stromal cells from FBM, ABM, and CB using RI-PCR, and how the differences affect the repopulating ability of the hematopoietic stem cells after long term bone marrow culture (LTBMC). Stromal cells were prepared from 8 samples each of FBM, ABM, CS. The expression for stem cell factor (SCF), GM-CSF, G-CSF, M-CSF, IL-3, IL-6, IL-10, and IL-11 was detected by RT-PCR. Strong expression of SCF and IL-11 was observed in the stromal cells but was not detected in any of FBM specimens. IL-6 was positive in 6/8 ABM but not only 1/9 in FBM and 8 in CB. Although G-CSF was not observed in CB, it was expressed in all FBM and ABM specimens. In contrast, expression of GM-CSF, IL-3 and IL-10 was similar in all three sources. These results indicate that there are significant age-related changes in cytokine expression at different maturational stages. Further, LTBMC was performed to examine the ability of stromal cells to support hematopoietic stem cells from allogeneic bone marrows. The number of colonies derived from either FBM or ABM were greater when inoculated with fetal stromal cells. Our results suggest an important regulatory role of these cytokines in differentiation and proliferation of stem cells during ontogeny which may provide a basis for selection of stem cells for transplantation.