Promotive effect of macrophage colony-stimulating factor on long-term engraftment of murine hematopoietic stem cells

Complex interactions in EML cell stimulation by stem cell factor and IL-3

Erythroid myeloid lymphoid (EML) cells are an established multipotent hematopoietic precursor cell line that can be maintained in medium including stem cell factor (SCF). EML cultures contain a heterogeneous mixture of cells, including a lineage-negative, CD34+ subset of cells that propagate rapidly in SCF and can clonally regenerate the mixed population. A second major subset of EML cells consists of lineage-negative. CD34- cells that can be propagated in IL-3 but grow slowly, if at all, in SCF, although they express the SCF receptor (c-kit). The response of these cells to IL-3 is stimulated synergistically by SCF, and we present evidence that both the synergy and the inhibition of c-kit responses may be mediated by direct interaction with IL-3 receptor. Further, the relative level of tyrosine phosphorylation of various substrates by either cytokine alone differs from that produced by the combination of the two cytokines, suggesting that cell signaling by the combination of the two cytokines differs from that produced by either alone.

Treatment with at homeopathic complex medication modulates mononuclear bone marrow cell differentiation

A homeopathic complex medication (HCM), with immunomodulatory properties, is recommended for patients with depressed immune systems. Previous studies demonstrated that the medication induces an increase in leukocyte number. The bone marrow microenvironment is composed of growth factors, stromal cells, an extracellular matrix and progenitor cells that differentiate into mature blood cells. Mice were our biological model used in this research. We now report in vivo immunophenotyping of total bone marrow cells and ex vivo effects of the medication on mononuclear cell differentiation at different times. Cells were examined by light microscopy and cytokine levels were measured in vitro. After in vivo treatment with HCM, a pool of cells from the new marrow microenvironment was analyzed by flow cytometry to detect any trend in cell alteration. The results showed decreases, mainly, in CD11b and TER-119 markers compared with controls. Mononuclear cells were used to analyze the effects of ex vivo HCM treatment and the number of cells showing ring nuclei, niche cells and activated macrophages increased in culture, even in the absence of macrophage colony-stimulating factor. Cytokines favoring stromal cell survival and differentiation in culture were induced in vitro. Thus, we observe that HCM is immunomodulatory, either alone or in association with other products.

Improved hematopoietic stem cell engraftment following ex vivo expansion of murine marrow cells with SCF and Flt3L

BACKGROUND

In vitro incubation of murine BM cells with IL-3, IL-6, IL-11 and SCF induces expansion of HPC but fails to preserve 'engraftability' in comparison with normal untreated marrow cells. We studied how culturing marrow cells for 48 and 72 h with a combination of the cytokines SCF and Flt3L influences cell expansion and engraftability.

METHODS

Competitive repopulation of lethally irradiated C57BL/6 mice was used to examine engraftability of ex vivo cytokine-expanded Ptprc chimeric BM. A methylcellulose in vitro assay was used to determine the expansion of substitute progenitors.

RESULTS

Both cytokine combinations successfully expanded progenitor populations when assayed in methylcellulose culture in vitro. After 72 h, the colony numbers of the expansion cultures increased 61% with IL-3, IL-6, IL-11 and SCF stimulation and 96% with SCF and Flt3L stimulation. Engraftment of competitively transplanted cells, cultured with IL-3, IL-6, IL-11 and SCF, consistently dropped to levels below 16%. However, 48 h culture with SCF and Flt3L resulted in 53.5+/-1.6% engraftment at 17 days and 64+/-3.7% engraftment at 19 weeks post-transplantation. Extending the cytokine exposure to 72 h resulted in 70+/-4.4% short-term engraftment at 17 days, and 64+/-2.4% engraftment at 19 weeks post-transplantation.

DISCUSSION

The data demonstrate the ability of SCF and Flt3L cytokine-stimulated BM cells to maintain short- and long-term engraftability. We conclude that these cytokines play a crucial role in maintaining engraftment of hematopoietic progenitors.

Activation of mononuclear bone marrow cells treated in vitro with a complex homeopathic medication

Canova is a Brazilian homeopathic medication with immunomodulatory properties, recommended for patients where the immune system is depressed. Previous studies demonstrated that Canova induces up-regulation in numbers of leukocytes. The bone marrow microenvironment is composed of growth factors, stromal cells, extracellular matrix and progenitor cells that differentiate into mature blood cells. We now report the effect of in vitro administration of the medication on the mononuclear differentiation of the bone marrow cell. Swiss mice femurs were dissected cleaned and the cells of the marrow were flushed. The cells were plated, treated or not, incubated for different times and processed for light, transmission and scanning electron, and confocal microscopy analysis. Bone marrow cells showed an enhanced proliferation in vitro in response to Canova medication and Canova plus M-CSF and an increase was also observed in the numbers of the cell niches and ring-shaped nuclei cells. Confocal and transmission and scanning electron microscopy showed the stages of monocyte maturation, with resting and activated cells. With Canova treatment there was a marked increase in cell size, which is mainly attributable to the augmented cytoplasm, an increase in the number of mitochondria, expansion of the RER and an enlarged Golgi. The response to Canova treatment indicates that it influences mononuclear differentiation and activation of bone marrow progenitor and stromal cells.