The role of lymphocytes and monocytes in hematopoietic growth factor production by peripheral blood mononuclear cells

Stimulated peripheral blood mononuclear cells (MNC) are one of the richest described physiologic sources of colony-stimulating activity. To understand the molecular basis for, and the cellular sources of, this MNC activity, we cultured purified human lymphocytes and monocytes for 2 hr to 6 days and examined colony-stimulating factor (CSF) gene activity by Northern blot analysis. We show that MNC are capable of expressing messenger RNA for macrophage (M)-CSF, granulocyte (G)-CSF, GM-CSF, and multi-CSF when stimulated with mitogens. The time courses of induction of these genes differ, with G-CSF induction preceding that of the other CSFs. In addition, the spectra of CSFs produced by cell populations enriched for lymphocytes, monocytes, or macrophages differ. The implications of these findings for the selective activation of hematopoiesis are discussed.     

Spontaneous and granulocyte–colony-stimulating factor-enhanced marrow response and progenitor cell mobilization in mice after myocardial infarction

Background aimsHematopoietic (HPC), mesenchymal (MPC) and/or endothelial (EPC) progenitor cells are being studied to repair the myocardium after acute or chronic ischemia. We examined marrow response to myocardial infarction (MI) and the ability of granulocyte–colony-stimulating factor (G-CSF) to enhance mobilization of HPC, MPC and EPC in peripheral blood (PB) and bone marrow (BM) of MI mice.MethodsWe induced MI in C57Bl/6 mice, while sham-operated (SO) animals were similarly operated on but without coronary artery ligation. Animals were treated with either saline or G-CSF, from day ?5 to day +5 after MI or from day 0 to day +5. Progenitor cell numbers in PB and BM were evaluated by fluorescence-activated cell sorting (FACS) analysis and cell culture.ResultsWhite blood cells (WBC) decreased in BM and increased in PB after MI; G-CSF amplified this effect in BM but not in PB. HPC numbers decreased in BM after MI, while HPC and granulocyte–macrophage colony-forming units (GM-CFU) increased in PB only after G-CSF treatment, and more prominently so in MI than in SO mice. MPC and fibroblast–colony-forming units (F-CFU) as well as EPC were mobilized into the PB after MI and further after G-CSF treatment. Plasma troponin T concentrations decreased after G-CSF treatment.ConclusionsBM is globally affected by acute MI, but not simple body injury, with intense mobilization of marrow MPC and EPC into the PB but inhibition of HPC. Progenitor cell entry into the PB may be paralleled by depletion of their BM pools. G-CSF is required for HPC mobilization and enhances MPC and EPC entry into the PB.     

Safety and efficacy of granulocyte–colony-stimulating factor administration following autologous intramuscular implantation of bone marrow mononuclear cells: a randomized controlled trial in patients with advanced lower limb ischemia

Background aimsThe aim was to investigate the therapeutic effect of granulocyte–colony-stimulating factor (G-CSF) administration following implantation of autologous bone marrow mononuclear cells (BM MNC) for patients with lower limb ischemia.MethodsThe design was a randomized controlled trial. Fifteen patients with severe chronic limb ischemia were treated with autologous BM MNC [without G-CSF (MNC–G-CSF) or combined with G-CSF administration for 5 days following transplantation (MNC+G-CSF)].ResultsAll clinical parameters, including ankle brachial index, visual analog scale and pain-free walking distance, showed a mean improvement from baseline, which was measured at 4 and 24 weeks after transplantation in both groups. However, in three (20%) patients, the clinical course did not improve and limb salvage was not achieved. No significant difference was observed among the patients treated in the MNC–G-CSF and MNC+G-CSF groups. No severe adverse reactions were reported during the study period. No relationship was observed between both the numbers of viable MNC or CD34⁺ cells and the clinical outcome.ConclusionsAutologous transplantation of BM MNC into ischemic lower limbs is safe, feasible and efficient for patients with severe peripheral artery disease. However, the administration of G-CSF following cell transplantation does not improve the effect of BM MNC implantation and therefore would not have any beneficial value in clinical applications of such cases.     

Suppression of Proteoglycan-Induced Autoimmune Arthritis by Myeloid-Derived Suppressor Cells Generated In Vitro from Murine Bone Marrow

Background

Myeloid-derived suppressor cells (MDSCs) are innate immune cells capable of suppressing T-cell responses. We previously reported the presence of MDSCs with a granulocytic phenotype in the synovial fluid (SF) of mice with proteoglycan (PG)-induced arthritis (PGIA), a T cell-dependent autoimmune model of rheumatoid arthritis (RA). However, the limited amount of SF-MDSCs precluded investigations into their therapeutic potential. The goals of this study were to develop an in vitro method for generating MDSCs similar to those found in SF and to reveal the therapeutic effect of such cells in PGIA.

Methods

Murine bone marrow (BM) cells were cultured for 3 days in the presence of granulocyte macrophage colony-stimulating factor (GM-CSF), interleukin-6 (IL-6), and granulocyte colony-stimulating factor (G-CSF). The phenotype of cultured cells was analyzed using flow cytometry, microscopy, and biochemical methods. The suppressor activity of BM-MDSCs was tested upon co-culture with activated T cells. To investigate the therapeutic potential of BM-MDSCs, the cells were injected into SCID mice at the early stage of adoptively transferred PGIA, and their effects on the clinical course of arthritis and PG-specific immune responses were determined.

Results

BM cells cultured in the presence of GM-CSF, IL-6, and G-CSF became enriched in MDSC-like cells that showed greater phenotypic heterogeneity than MDSCs present in SF. BM-MDSCs profoundly inhibited both antigen-specific and polyclonal T-cell proliferation primarily via production of nitric oxide. Injection of BM-MDSCs into mice with PGIA ameliorated arthritis and reduced PG-specific T-cell responses and serum antibody levels.

Conclusions

Our in vitro enrichment strategy provides a SF-like, but controlled microenvironment for converting BM myeloid precursors into MDSCs that potently suppress both T-cell responses and the progression of arthritis in a mouse model of RA. Our results also suggest that enrichment of BM in MDSCs could improve the therapeutic efficacy of BM transplantation in RA.     

Production of granulocyte colony-stimulating factor and granulocyte/macrophage-colony-stimulating factor after interleukin-1 stimulation of marrow stromal cell cultures from normal or aplastic anemia donors.

We have studied stromal cell function in naive or interleukin-1 (IL-1)-stimulated (100 pg/ml) long-term marrow cultures (LTC) from 12 normal donors and 21 patients with severe aplastic anemia (AA). Conditioned media (CM) from normal LTC contained levels of erythroid burst-promoting activity (BPA) and granulocyte/macrophage (GM) colony-stimulating activity (CSA) comparable to those previously described (Migliaccio et al., [1990] Blood, 75:305-312). The addition of IL-1 to these cultures increased the level of CSA and, specifically, of granulocyte colony-stimulating factor (G-CSF) released. Anti-GM-CSF antibody neutralized BPA and CSA in normal naive LTC CM but only the CSA in the CM from IL-1-stimulated LTC. Since the concentrations of GM-CSF, as detected with a specific immunoassay, did not increase after IL-1 treatment, these data suggest that IL-1-stimulated cultures contain an unidentified growth factor having BPA. CM from AA stromal cells contained levels of CSA comparable to those observed in normal stromal cell CM but had significantly lower levels of BPA. Neither anti-GM-CSF nor anti-IL-3 antibodies neutralized the BPA in AA stromal cell CM. This activity may be related to that found in the CM of IL-1-treated normal stromal cells. In nearly 50% of stromal cell cultures of AA patients, addition of IL-1 failed to increase the BPA, CSA, or G-CSF. The presence of an inhibitor in naive or IL-1-treated AA stromal cell CM was excluded by adding the CM to IL-3-stimulated cultures. These findings suggest that G-CSF and GM-CSF genes are differentially regulated in the marrow microenvironment. Furthermore, a marrow microenvironment, deficient in BPA production and, in some cases, unresponsive to IL-1 could contribute to marrow failure in some patients with AA.     

Complement sensitivity of erythroid and myeloid precursors in paroxysmal in nocturnal hemoglobinuria

To test the hypothesis that paroxysmal nocturnal hemoglobinuria (PNH) is a hematopoietic stem cell disorder, the growth of BFU-e and CFU-gm and the complement sensitivity of cultured cells from BFU-e and CFU-gm colonies, as well as of unipotential progenitor cells (CFU-gm and BFU-e), were examined in five PNH patients. BFU-e growth was reduced in the three patients examined, and poor CFU-gm growth was noted in three of the five patients. Compared to normals, BFU-e and CFU-gm colonies in all patients demonstrated an increased susceptibility to the lytic action of complement when the release of 59Fe and myeloperoxidase was measured as specific markers for monitoring membrane damage. Compared to the growth of normal bone marrow cells, CFU-gm growth was significantly inhibited by pretreatment of bone marrow mononuclear cells with monoclonal OKIal antibody and complement. These findings support the proposition that a membrane defect predisposing blood cells to complement-mediated lysis may occur at the level of unipotential progenitor cells.     

Developmental regulation of RNA transcript destabilization by A + U-rich elements is AUF1-dependent

The developmental immaturity of neonatal phagocytic function is associated with decreased accumulation and half-life (t((1)/(2))) of granulocyte/macrophage colony-stimulating factor (GM-CSF) mRNA in mononuclear cells (MNC) from the neonatal umbilical cord compared with adult peripheral blood. The in vivo t((1)/(2)) of GM-CSF mRNA is 3-fold shorter in neonatal (30 min) than in adult (100 min) MNC. Turnover of mRNA containing a 3'-untranslated region (3'-UTR) A + U-rich element (ARE), which regulates GM-CSF mRNA stability, is accelerated in vitro by protein fractions enriched for AUF1, an ARE-specific binding factor. The data reported here demonstrate that the ARE significantly accelerates in vitro decay of the GM-CSF 3'-UTR in the presence of either neonatal or adult MNC protein. Decay intermediates of the GM-CSF 3'-UTR are generated that are truncated at either end of the ARE. Furthermore, the t((1)/(2)) of the ARE-containing 3'-UTR is 4-fold shorter in the presence of neonatal (19 min) than adult (79 min) MNC protein, reconstituting developmental regulation in a cell-free system. Finally, accelerated ARE-dependent decay of the GM-CSF 3'-UTR in vitro by neonatal MNC protein is significantly attenuated by immunodepletion of AUF1, providing new evidence that this accelerated turnover is ARE- and AUF1-dependent.     

In vivo effect of rhGM-CSF And rhG-CSF on monocyte HLA-DR expression of septic neonates

OBJECTIVE: To investigate the effect of rhGM-CSF and rhG-CSF on the monocyte HLA-DR expression of septic neonates. SUBJECTS: 60 septic neonates and 41 healthy ones. Septic neonates were randomly assigned into three treatment groups, the GM-CSF group [n=20, rhGM-CSF 5 mcg/kg/d for 4 days, intravenously over 2h (IV)], the G-CSF group (n=20, rhG-CSF 10 mcg/kg/d for 4 days, IV) and the placebo group (n=20, normal saline for 4 days, IV). MEASUREMENTS: Serial (days 0,1, 3 and 5 after the onset of sepsis) measurements of the percentage of HLA-DR positive monocytes (%HLA-DR+ monocytes) and mean fluorescence intensity (MFI) by flow-cytometry as well as the absolute monocyte counts (AMC). MAIN RESULTS: On day 0, the HLA-DR expression of the septic neonates (%HLA-DR+ monocytes: 38%+/-1.8% (mean+/-SEM) and MFI: 73+/-3.4) was significantly lower than the healthy control values (%HLA-DR+ monocytes: 68%+/-2% and MFI: 123+/-4.6) (P<0.0001, for both parameters). On follow up (days 1, 3 and 5), a significant increase of HLA-DR expression was observed in all the groups of septic neonates. Healthy control values of %HLA-DR+ monocytes were reached by day 1 in the GM-CSF group and by day 3 in the G-CSF and placebo groups. Healthy control values of MFI were reached by day 3 in all groups of septic neonates. The AMC showed a significant increase in the GM-CSF group (during the whole follow up period) and in the G-CSF group (for the first 3 days of follow up). CONCLUSIONS: The monocyte HLA-DR expression is depressed on the onset of neonatal sepsis and is progressively restored during the following days. Treatment with rhGM-CSF results in an earlier increase of the number of monocytes expressing the HLA-DR.     

Effects of recombinant human tumor necrosis factor (rhTNF) on normal human and mouse hemopoietic progenitor cells

We examined the effects of recombinant human tumor necrosis factor (rhTNF) on normal human and murine granulocyte-macrophage (CFU-gm) and erythroid (CFU-e, BFU-e) progenitor cells. We suppressed in vitro colony formation by human marrow CFU-gm, CFU-e and BFU-e or peripheral blood BFU-e by adding rhTNF to the culture in a dose-related manner. A half-maximal inhibition was observed with 1-10 ng/ml. Leukemic cell line K562 cells were found to be sensitive to rhTNF in the clonogenic colony assay. However, the clonal growth of murine marrow CFU-e and BFU-e colonies was less than 50% inhibited and CFU-gm growth was unaffected even at a concentration of 1,000 ng/ml. We observed slight to moderate inhibition after 24 h pulse exposure of both human and murine-committed progenitors to rhTNF prior to the culture. Intravenous injection of 1 mg/kg of rhTNF caused a marked decrease in marrow erythroid progenitors and consequently caused anemia in the mice. Our data indicate that rhTNF has a suppressive effect on normal human and murine hemopoietic colony formation in vitro and murine erythropoiesis in vivo.     

Synergistic effects of purified recombinant human and murine B cell growth factor-1/IL-4 on colony formation in vitro by hematopoietic progenitor cells. Multiple actions

Purified recombinant human B cell growth factor-1/IL-4 was evaluated, alone and in combination, with purified preparations of recombinant human (rhu) CSF or erythropoietin (Epo) for effects on colony formation by human bone marrow CFU-GM progenitor cells (GM) and burst forming unit-E progenitor cells. rhu IL-4 synergized with rhu G-CSF to enhance granulocyte colony formation, but had no effect on CFU-GM colony formation stimulated by rhu GM-CSF, rhu IL-3, or rhu CSF-1. Rhu IL-4 synergized with Epo to enhance BFU-E colony formation equal to that of Epo plus either rhu IL-3, rhu GM-CSF, or rhu G-CSF. Removal of adherent cells and T lymphocytes did not influence the synergistic activities of rhu IL-4. Rmu IL-4, synergized with rhu G-CSF, but not with rmu GM-CSF, rmu IL-3, or natural mu CSF-1, to enhance CFU-GM (mainly granulocyte) colony numbers by a greater than 90% pure preparation of murine CFU-GM. Also, rhu IL-4 at low concentrations enhanced release of CSF and at higher concentrations the release also of suppressor molecules from human monocytes and PHA-stimulated human T lymphocytes. Use of specific CSF antibodies suggested that rhu IL-4 was enhancing the release of G-CSF and CSF-1 from monocytes and the release of GM-CSF and possibly G-CSF from PHA-stimulated T lymphocytes. Use of antibodies for TNF-alpha, IFN-gamma, or TNF-beta as well as measurement of TNF and IFN titers suggested that the suppressor molecule(s) released from monocytes were acting with TNF-alpha and those released from PHA-stimulated T lymphocytes were acting with IFN-gamma. These results implicate B cell growth factor-1/IL-4 as a synergistic activity for hematopoietic progenitors and suggest that the actions can be on both progenitor and accessory cells.     

Combined administration of G-CSF and GM-CSF stimulates monocyte-derived pro-angiogenic cells in patients with acute myocardial infarction

Mobilization of endothelial progenitor cells has been suggested to contribute to neo-vascularization of ischemic organs. Aim of this study was to investigate whether the combination of granulocyte colony stimulating factor (G-CSF) and granulocyte-macrophage (GM)-CSF may influence the expansion of circulating KDR+ cells in patients with acute myocardial infarction (AMI). KDR+ cells significantly increased in peripheral blood of AMI patients treated with G-CSF and GM-CSF compared to untreated patients. This KDR+ cells population was CD14+ but not CD34+ or CD133+. CD14+/KDR+ cells were also obtained in vitro by culturing mononuclear cells from healthy donors in a Rotary Cell Culture System in the presence of G-CSF + GM-CSF, but not of the individual growth factors. CD14+/KDR+ cells, obtained from patients or from in vitro culture, co-expressed hematopoietic (CD45, CD14) and endothelial markers (CD31, CD105, and VE-cadherin). CD14+/KDR+, but not CD14+/KDR- cells, stimulated the organization of human microvascular endothelial cells into capillary-like structures on Matrigel both in vitro and in vivo. The combination of G-CSF and GM-CSF induced a CD14+/KDR+ cell population with potential pro-angiogenic properties.     

Interleukin 1 stimulates human endothelial cells to produce granulocyte-macrophage colony-stimulating factor and granulocyte colony-stimulating factor

Endothelial cells are a potent source of hematopoietic growth factors when stimulated by soluble products of monocytes. Interleukin 1 (IL 1) is released by activated monocytes and is a mediator of the inflammatory response. We determined whether purified recombinant human IL 1 could stimulate cultured human umbilical vein endothelial cells to release hematopoietic growth factors. As little as 1 U/ml of IL 1 stimulated growth factor production by the endothelial cells, and increasing amounts of IL 1 enhanced growth factor production in a dose-dependent manner. Growth factor production increased within 2 to 4 hr and remained elevated for more than 48 hr. To investigate the molecular basis for these findings, oligonucleotide probes for granulocyte-macrophage colony-stimulating factor (GM-CSF), granulocyte colony-stimulating factor (G-CSF), macrophage colony-stimulating factor (M-CSF), and multi-CSF were hybridized to poly(A)-containing RNA prepared from unstimulated and IL 1-stimulated endothelial cells. Significant levels of GM-CSF and G-CSF, but not M-CSF or multi-CSF, mRNA were detected in the IL 1-stimulated endothelial cells. Biological assays performed on the IL 1-stimulated endothelial cell-conditioned medium confirmed the presence of both GM- and G-CSF. These results demonstrate that human recombinant IL 1 can stimulate endothelial cells to release GM-CSF and G-CSF, and provide a mechanism by which IL 1 could modulate both granulocyte production and function during the course of an inflammatory response.     

Effect of stem cell mobilization with cyclophosphamide plus granulocyte colony-stimulating factor on morphology of haematopoietic organs in mice

Both granulocyte colony-stimulating factor (G-CSF) and cyclophosphamide (CY) are employed in the clinic as mobilizing agents to stimulate the egress of haematopoietic stem/progenitor cells (HSPC) from bone marrow (BM) into peripheral blood (PB). However, although both compounds are effective, the simultaneous administration of G-CSF + CY allows for optimal mobilization. The aim of this study was to compare morphological changes in major haematopoietic organs in mice mobilized by G-CSF + CY. We employed the standard G-CSF + CY mobilization protocol, in which mice were injected at day 0 with a single dose of CY followed by daily injection of G-CSF for 6 consecutive days. We noticed that the cytoreductive effect of CY on BM and spleen tissue was compensated at day 2 by the pro-proliferative effect of G-CSF. Furthermore, as evidenced by histological examination of BM sections at day 4, egress of haematopoietic cells from BM was accelerated by 2 days as compared to mobilization by G-CSF or CY alone; also, by day 6 there was accumulation of early haematopoietic (Thy-l(low) c-kit+) cells in the spleens and livers of mobilized animals. This implies that HSPC that are mobilized from BM and circulate in PB may 'home' to peripheral organs. We envision that such an accumulation of these cells in the spleen (which is a major haematopoietic organ in mouse) allows them to participate in haematopoietic reconstitution. Their homing to other sites (for example the liver) is evidence that BM-derived stem cells are playing a pivotal role in organ/tissue regeneration. The potential involvement of major chemoattractants for stem cells, like stromal-derived factor-1 which is induced by CY in various regenerating organs such as the liver, requires further study. We conclude that inclusion of CY into mobilization protocols on the one hand efficiently increases the egress of HSPC from the BM, but on the other hand may lead to the relocation of BM stem cell pools to peripheral tissues.     

Radiosensitivity increases with differentiation status of murine hemopoietic progenitor cells selected using enriched marrow subpopulations and recombinant growth factors

The radiosensitivity of populations of colony-forming cells (CFC) in murine bone marrow was investigated using different recombinant colony-stimulating factors (CSFs; murine IL-3 and granulocyte-macrophage CSF and human granulocyte CSF), or purified murine macrophage CSF. With unfractionated normal bone marrow the CFC increased in radiosensitivity as they progressed through the granulocyte lineage. The D0 values ranged from 129 +/- 12 cGy for CFC stimulated with GM-CSF down to 42 +/- 2 cGy after stimulation with G-CSF. IL-3 stimulated a CFC population which gave the only survival curve with a shoulder (n = 1.9 +/- 0.3). With semipurified populations of primitive or bipotential CFC, D0 values were generally lower with respect to the equivalent values for unpurified bone marrow (range 62 +/- 7 cGy to 135 +/- 7 cGy). Changes in cluster/colony ratio and colony morphology together possibly with products of accessory cells influence the interpretation of the radiosensitivity parameters.     

Effect of recombinant human interleukin 3, granulocyte-macrophage colony-stimulating factor and granulocyte colony-stimulating factor on human BFU-e in serum-free cultures

The effects of recombinant human hemopoietic growth factors on early and late human erythroid progenitors (BFU-e and CFU-e) were investigated in serum-free cultures. Recombinant human erythropoietin (rhEpo) induced the formation of not only human CFU-e-derived colonies but also human BFU-e-derived bursts. Recombinant human interleukin 3 (rhIL-3) alone did not induce the formation of human BFU-e-derived bursts and human CFU-e-derived colonies. In the presence of rhEpo, rhIL-3 dose dependently increased the number of bursts stimulated by rhEpo, although rhIL-3 did not have the augmentative effect on human CFU-e growth. On the other hand, rhIL-3 did not stimulate the formation of murine BFU-e-derived bursts, and murine IL-3 did not stimulate the formation of human BFU-e-derived bursts. The results indicated that the burst-promoting activity of IL-3 was species-specific between human and murine cells. Recombinant human GM-CSF (rhGM-CSF) or recombinant human G-CSF (rhG-CSF) failed to induce human burst formation and did not augment the effect of rhEpo on human burst formation. The results of the present study suggest that in vitro, IL-3 can stimulate BFU-e in collaboration with Epo, but GM-CSF and G-CSF do not stimulate BFU-e growth in the presence or absence of Epo.     

Granulocyte interactions with GM-CSF and G-CSF secretion by endothelial cells and monocytes

We have, in previous studies, characterized the cytokine and cellular regulation of GM-CSF and G-CSF production by monocytes and endothelial cells. In this study, we investigated the regulatory role of granulocytes. The addition of granulocytes to endotoxin-stimulated monocytes dose-dependently decreased both GM-CSF and G-CSF concentrations, presumably by absorbing the cytokines. A similar dose-dependent decrease in GM-CSF concentration was found when granulocytes were added to IL-1-stimulated endothelial cells. In contrast, G-CSF secretion by endothelial cells responded to granulocytes in a biphasic fashion. At low granulocyte concentrations, endothelial cells responded with an increased G-CSF secretion, but at high concentrations of granulocytes G-CSF secretion was down modulated. Our results suggest that there exist two loops between granulocytes and endothelial cells for regulating G-CSF activity. Granulocytes can stimulate G-CSF secretion by activated endothelial cells but can also decrease the biological activity by absorbing the cytokine. These mechanisms might be involved in the regulation of the local and systemic levels of granulocytes.     

Effects of granulocyte–colony-stimulating factor on progenitor cell mobilization and heart perfusion and function in normal mice

Background aimsMobilization of stem cells and progenitor cells from the bone marrow (BM) into the peripheral blood (PB) by granulocyte–colony-stimulating factor (G-CSF) is being investigated for cardiac regeneration in ischemic heart disease. However, hematopoietic (HPC), mesenchymal (MPC) and endothelial (EPC) progenitor mobilization have not been optimized and the effect of G-CSF on myocardial perfusion and cardiac function in a normal heart has never been studied.MethodsNormal mice were injected daily for 1–10 days with subcutaneous recombinant human G-CSF. PB and BM were evaluated for HPC and EPC by flow cytometry and HPC and MPC by hematopoietic (CFU-GM) and mesenchymal (CFU-F) colony assays. Echocardiography, microSPECT imaging, cardiac catheterization and immunohistochemistry were performed in mice treated for 10 days.ResultsHPC and CFU-GM in PB peaked after 2 days, CFU-F after 4 days and EPC after 3 days. Thereafter, while HPC temporally decreased before showing a second peak, EPC remained detectable only at low levels. In BM, hematopoietic stem cells (HSC) and CFU-GM did not increase much overall but peaked twice on days 2 and 7. EPC (peak on day 7) production increased in the BM, but CFU-F formation declined considerably after day 2. G-CSF enhanced myocardial perfusion and vascularization but impaired hemodynamic performance of the heart through apparently increased ventricular wall rigidity.ConclusionsG-CSF induces the mobilization of HPC, EPC and CFU-F progenitors in PB according to very different patterns, and has a significant impact on perfusion and function of the normal heart.     

Levels of human serum granulocyte colony-stimulating factor and granulocyte-macrophage colony-stimulating factor under pathological conditions

Levels of serum granulocyte colony-stimulating factor (G-CSF) and granulocyte-macrophage colony stimulating factor (GM-CSF) in patients with various leukocyte disorders were estimated by enzyme linked immunosorbent assay (ELISA). Some cases of acute myelogenous leukemia and aplastic anemia showed elevated serum levels of G-CSF and/or GM-CSF, whereas almost all of 23 healthy controls showed G-CSF and GM-CSF levels lower than 100 pg/ml. High levels of both types of CSF were noted in patients with granulocytosis due to infection. These levels became lower after resolution of the infection. Daily changes in serum CSF levels were also examined in a patient with autoimmune neutropenia, and it was found that the peripheral neutrophilic granulocyte count changed almost in parallel with the serum G-CSF level but not with GM-CSF, following the pattern with a delay of about 4–5 h, suggesting the possibility that G-CSF mainly regulates peripheral neutrophil circulation.     

Examination of survival, proliferation and cell surface antigen expression of human monocytes exposed to macrophage colony-stimulating factor (M-CSF)

The effects of macrophage colony-stimulating factor (M-CSF or CSF-1) on the survival, proliferation, maturation and activation of human blood monocytes were examined. M-CSF (100-1,000 U/ml) doubled the number of monocytes surviving after eight days in culture and accelerated the usual increase in cell volume. Antiserum to M-CSF abolished both of these effects. There was no sizable increase in 3H-thymidine incorporation in monocytes over this time period. Of various factors tested, including gamma-interferon (gamma-IFN), interleukin (IL) 1 alpha, granulocyte CSF (G-CSF), platelet-derived growth factor (PDGF), and lipopolysaccharide (LPS), only granulocyte-macrophage CSF (GM-CSF) could also enhance survival and augment cell volume. While antiserum to human M-CSF eliminated the increase in survival induced by GM-CSF, it could not ablate the GM-CSF-stimulated increase in monocyte cell volume. Monocyte cell surface markers that increase with maturation (i.e., Fc gamma RIII) or with activation (i.e., Fc gamma RI) were unaffected by incubation with M-CSF.     

Induction of the granulocyte-macrophage colony-stimulating factor (CSF) receptor by granulocyte CSF increases the differentiative options of a murine hematopoietic progenitor cell.

32DC13(G) is an interleukin-3-dependent murine hematopoietic precursor cell line which differentiates into neutrophilic granulocytes upon exposure to granulocyte colony-stimulating factor (G-CSF) but ceases to proliferate and dies when exposed to granulocyte-macrophage (GM)-CSF. Surface receptors for GM-CSF are undetectable on 32DC13(G) cells but can be induced by priming the cells with G-CSF. Exposure of the G-CSF-primed cells to GM-CSF then results in the generation of monocytes as well as granulocytes. The acquired competence to respond to GM-CSF remains irreversibly encoded in the primed cells, although the GM-CSF receptor can be down regulated by interleukin-3. This phenomenon suggests a mechanism by which hematopoietic precursors may obtain additional receptors, thereby increasing their differentiative potential.