1,721,059 research outputs found
Proliferation of human hematopoietic progenitors in long-term bone marrow cultures in gas permeable plastic bags is enhanced by colony-stimulating factors.
No full textWe compared the recovery of human hematopoietic progenitors in long-term bone marrow culture (LTBMC) initiated in tissue culture (TC) flasks to that in "Lifecell" bags, which are gas-permeable plastic bags in which feeder-layer cells cannot adhere. Our results showed that granulocyte-macrophage colony-forming unit (CFU-GM) and erythroid burst-forming unit (BFU-E) cumulative recovery in cultures from normal donor marrow, expressed as a percent of the initial inoculum, was not statistically different in the two culture systems up to week 8, when the cultures were terminated: 31.5 +/- 19 (flask) vs 30 +/- 14 (bag) and 15.5 +/- 12 (flask) vs 11.5 +/- 8 (bag), respectively. The effects of weekly addition of recombinant human (r-hu)-interleukin 1 (IL1) and r-hu-interleukin 3 (IL3) were then studied, alone and combined, at two different concentrations. Addition of IL1, either alone or combined with IL3, in LTBMC established in flasks induced an increase of hematopoietic progenitors for the first week, but BFU-E and CFU-GM were no longer detectable at weeks 4 and 6, respectively. Analysis of adherent layer cells showed a decreased cellularity, no adipogenesis, and early disappearance of bone marrow (BM) progenitors, whereas the cycling rate of myeloid precursors, by cytosine arabinoside (Ara-C) suicide assay, was similar to that of untreated cultures. Conversely, IL3 alone (5 ng/ml) resulted in 3.6- and 5.4-fold peak increases for CFU-GM and BFU-E, respectively, at week 1 (adherent plus nonadherent cells), and the recovery of BM cells was still higher than that of control flasks at week 8. By comparison, stimulation with colony-stimulating factors (CSFs) of BM cells grown in bags never affected the longevity of the culture. Addition of IL3 (5 ng/ml) induced a higher recovery of total cells, CFU-GM (range: 1.6- to 15-fold peak increase during the culture), and BFU-E (1.2- to 3-fold) compared to the untreated controls. Bags treated with IL1 alone demonstrated only transient beneficial effects, and the number of hematopoietic precursors fell below the level of control bags during the culture. IL1 and IL3 induced 1.8- and 5.3-fold peak increases in BFU-E and CFU-GM at weeks 1 and 4, respectively. Simultaneous flow cytometric analysis of CD34+/CD33+ cells and DNA content showed increased numbers and proliferation of the committed BM progenitors when CSFs were added to the ba
Combination of hematopoietic growth factors containing IL-3 induce Acute Myeloid Leukemia Cell Sensitization to cycle specific and cycle non-specific drugs.
No full textLaboratory studies have suggested that hematopoietic growth factors (GF), combined with cytosine-arabinoside (Ara-C) can enhance cytotoxic effects of this agent against acute myeloid leukemia (AML) cells. While clinical trials based on this growth factor/chemotherapy combination (GF/CT) are progressing with discordant results, further information regarding the underlying mechanisms have been reported supporting this rationale and requiring additional investigation. To assess the role of cytokinetic changes in the GF/CT strategy and to evaluate if chemotherapeutic agents regimens other than Ara-C, when combined with GF, can enhance their cytotoxic effects, we have primed AML blasts with two cytokine combinations and then exposed these cells to the S-phase specific agent Ara-C as well as to the phase non-specific drug daunorubicin (DNR) and to the alkylating agent 4-hydroperoxycyclophosphamide (4-HC). The two cytokine combinations used for priming AML blasts were: (i) interleukin-3 (IL-3) + granulocyte-macrophage colony-stimulating factor (GM-CSF) + granulocyte colony-stimulating factor (G-CSF); and (ii) GM + G-CSF. Cytokinetic analysis in ten AML samples and clonogenic growth of leukemic colonies (CFU-L) in methylcellulose were used to detect proliferative and cytotoxic effects on AML samples. We report that in AML clonogenic cell growth can be stimulated by cytokines in 50% of the samples (4/8), and that Ara-C sensitization clearly occurs in two out of these four samples. Among the different cytokine combinations tested, the one containing IL-3 was the most effective through a cytokinetic mechanism consistent with recruitment (averaged G0 decrease p = 0.04; S-phase increase p = 0.005). Furthermore we observed increased cytotoxicity also to the phase non-specific drugs DNR and 4-HC, which may be mediated by other mechanisms recently described. We conclude that GF/CT combinations may also be beneficial in regimens containing drugs other than Ara-C, used for AML treatment, including bone marrow transplantation conditioning regimens
Gulati S.C., Jules-Elysee K., Whitmarsch K., Yahalom J., Reich L., Crown J., Motzer R., Coleman M., Lemoli R.M., Clarkson B.D., Portlock C., Gee T. and Mendelsohn J.
No full textThrombopoietin, interleukiun-11, and early-acting megakaryocyte growth factors in human myeloid leukemia cells
No full textIn this study we report our data on effects of early-acting megakaryocyte growth factors, particularly the c-mpl ligand also known as thrombopoietin (TPO) and interleukin-11 (IL-11), on cell proliferation and apoptosis (Apo) of primary acute myeloid leukemia (AML) cells. A proliferative response to TPO was noticed in the majority of AML samples (17/19) with an average increase of S-phase cells from 7.8% ± 1.5 to 14.5% ± 2.1 (p=0.0006). Resulting cell cycle activation did not always correlate with expression of the c-mpl receptor, although it was coupled, in the majority of samples, by an average decrease of apoptotic cells from 13% ± 0.7 to 8.8% ± 1.8 (p=0.05). Clonogenic cell growth (CFU-L) was confirmed in 5/17 of the samples with a mean colony number of 21.4 ± 9.6 × 105 cells plated. Conversely, effects of IL-11 on AML cells demonstrated that cell cycle changes (recruitment from G0 to S phase) were promoted only in a minority of samples (2/14) and there was little, if any, effect on CFU-L growth (mean colony number=17.5 ± 9.5) or Apo (from 13% ± 0.7 to 13.3±1.9). Combination of TPO with IL-11 induced a slight increase of clonogenic cell growth, while the addition of IL-3 or SCF to the c-mpl ligand significantly raised the mean colony numbers up to 119.2 ± 68.3 and 52.9±22.1 × 105 cells plated, respectively. In summary, TPO shows activity on AML cells by stimulating their proliferation in a significant proportion of cases and generally protecting the majority of AML blast cells from induction of Apo. Conversely, IL-11 exerts little effect on the cell cycle activation and Apo. These data help to understand regulation of myeloid leukemia cell growth and should be considered in the clinical use of early-acting megakaryocyte growth factors in acute leukemia.
Read More: http://informahealthcare.com/doi/abs/10.3109/1042819000905489
Impaired dendritic cell immunophenotype and function in heart transplant patients undergoing active cytomegalovirus infection.
No full textBackground. Human cytomegalovirus (HCMV) infects dendritic cells (DCs) in vitro and inhibits their maturation properties and their ability to stimulate T-cell proliferation and cytotoxicity. This study analyzed HCMV infection of DCs in vivo. Methods. We compared blood DCs and monocyte-derived DCs from heart-transplant patients undergoing an acute HCMV infection with DCs obtained from HCMV-negative transplant patients. Diagnosis of active HCMV infection was established by antigenemia test. Results. We detected viral RNA and antigens in defined DC subsets obtained from patients undergoing an active HCMV infection. In addition, we found an impaired immunophenotype in immature DCs from HCMV-positive subjects and a reduced ability of mature DCs from the same group of patients to stimulate allogenic T-cell proliferation. Conclusions. The impaired immunophenotype and function detected in DCs from transplant patients undergoing an active HCMV infection may be a mechanism used by the virus to interfere with early immune functions and thereby contributing to the HCMV-induced immunosuppression in these patients
Spontaneous mobilization of bone marrow-derived hematopoietic and endothelial progenitor/stem cells after orthotopic liver transplantation
No full textOpposite regulation of p27 in bone marrow and G-CSF mobilized peripheral blood CD34+ cells.
No full textPeripheral blood stem cells in acute myeloid leukemia: Biology and clinical applications
No full textClinical application of circulating stem cells for autologous transplantation is steadily expanding. It has become
increasingly clear that mobilized peripheral blood progenitor cells (PBSC) induce faster hematopoietic recovery, fewer febrile days, lower transfusion requirement and shorter hospitalization than bone marrow (BM)-derived
cells.More recently, rapid and sustained engraftment has also been reported using granulocyte colony-stimulating factor (G-CSF). This review analyzes the most recent advances in this field, addressing clinical and biological issues relevant to the use of autologous PBSC for AML patients.
Conclusions: Autologous BMT has been widely used as consolidation therapy in AML patients in first or second remission; however, delayed hematopoietic engraftment occurs in a substantial proportion of patients resulting in significant morbidity and mortality. This is mainly due to the adverse effects of prior intensive chemotherapy on BM harvest, a decrease in the normal stem cell pool in leukemic patients and, perhaps, toxic damage to the marrow microenvironment. Thus, several groups have investigated the use of circulating progenitor cells with the twofold aim of reducing transplant-related toxicity and widening the number of potential candidates for myeloablative therapy with the support of autologous stem cells.
As for hematopoietic reconstitution, previous studies have provided evidence that PBSC transplantation may offer some advantages over BM autografting. However, crucial issues such as asynchronous mobilization of normal vs leukemic cells and potential contamination of PBSC collections, timing of PBSC harvest, detection of minimal residual disease, and the
role of growth factors to accelerate hematological recovery and optimize stem cell collection have not been fully addressed.
In the present paper, the latest advances in his field have been reviewed with special focus on the biology of putative leukemic stem cells; operative guidelines have also been provided for those investigators who wish to design proper clinical trials on PBSC autotransplantation in acute leukemia. Definitive answers regarding the role of PBSC
will be coming from a large European randomized trial which is currently comparing peripheral blood stem cell and BM-derived graft
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