Biomedical subjects

I Bleiberg

Publications and source records attributed to I Bleiberg.

At least 19 recordsLinked to original sources

PubMed2005

The role of non-calcemic analogs of vitamin D in differentiation of cultured rat bone marrow into osteoblast-like cells: age and sex differences.

We have previously demonstrated that rat bone in vivo and rat bone cells in vitro, responded sex-specifically to gonadal steroids in stimulation of the specific activity of the BB isozyme of creatine kinase (CK), a marker for hormonal responsiveness. Pre-treatment with vitamin D analogs up-regulated the sex-specific responsiveness and sensitivity to gonadal steroids. We also found that mice cultured femoral bone marrow (BM) in the presence of dexamethasone (DEX) and 1,25(OH)2D3 (1,25D) or both differentiated into osteoblast-like cells (Obs), which acquired sex-specific responsiveness to gonadal steroids. This response was significantly augmented in the presence of both agents. In the present study, we examined the effect of age, sex and vitamin D non-hypercalcemic analogs on the differentiation of rat derived femoral BM into Obs. In female or male derived BM from intact but not gonadectomized rats DEX and DEX+1,25D increased the constitutive levels of CK. BM derived from old females showed lower stimulation of CK than BM originated from young females by estradiol (E2) or raloxifene (Ral) in the presence of both DEX and 1,25D. The non-hypercalcemic analogs of vitamin D: CB 1093 (CB), EB 1089 (EB) and MC 1288 (MC) were more effective than 1,25D in both age groups in stimulating CK in the absence of DEX. In the presence of DEX, there was a further increase in CK with the same differential effectiveness. BM from gonadectomized male or female rats lost the sex-specific response, responding to both E2 and dihydrotestosterone (DHT). BM derived from both intact and gonadectomized males and females, growing with DEX or DEX+1,25D showed increased specific activity of constitutive levels of alkaline phodphatase (AP). No significant stimulation of AP was seen in any BM by gonadal steroids. These findings suggest that manipulation of the hormonal milieu in early stages of differentiation sequence of Obs determines the subsequent selective responsiveness of the developing bone tissue to sex steroids. Also non-calcemic vitamin D analogs were more effective in this process than 1,25D and showed activity even in the absence of DEX and may be applied to the differentiation process for bone tissue engineering.

Aging↗

PubMed2001

Differential gene expression of cultured human osteoblasts.

Human cells with osteogenic capacity were studied for differential gene expression. In the first part of the study we compared gene expression of marrow stroma cells (MSC) in comparison to matured osteoblasts cultured from trabecular bone (TBC) that were analyzed by RT-PCR for series of messages. High expression was detected for PTH-r, TGFb1 and biglycan in TBC compared to MSC's. The messages for c-MYC, IL-6, IL-11, M-CSF, osteonectin, and osteocalcin were expressed at the same level in the two populations of cells. In the second part of the study, we analyzed gene expression within the MSC derived from 25 donors (2.5-49 years old) with respect to donors' age and gender. Increased message levels for M-CSF and biglycan were measured in correlation with age of the donors. Gender differences did not affect the expression of cytokines studied (IL-6, IL-11, MCSF, TGFb1). We investigated the effect of Dexamethasone treatment on MSC and monitored an increased expression of IL-11, M-CSF, biglycan, and osteocalcin messages. This study employs primary cell systems (MSC and TBC) to illustrate differential gene expression by osteoblastic cells. The expression was correlated with maturation status of the cells with respect to differences between donors.

Adolescent↗

PubMed2001

The hormonal milieu in early stages of bone cell differentiation modifies the subsequent sex-specific responsiveness of the developing bone to gonadal steroids.

We have established previously that rat bone tissue, as well as rat and human-derived bone cells in culture, show a sex-specific response to gonadal steroids in stimulation of the specific activity of the BB isozyme of creatine kinase (CK) and DNA synthesis. This response could be modified by manipulation of the endocrine environment during early stages in rat development. To further examine the influence of changing hormonal steroid milieu and vitamin D status on the action of gonadal steroids in developing bone tissue, we used two models of ectopic bone formation: demineralized tooth matrix (DTM) implanted under the skin, and femoral bone marrow (BM) transplanted under the kidney capsule of a syngeneic recipient mouse. The response to gonadal steroids in ossicles developed from implanted DTM depended on the recipient's gender; injection of estradiol 17beta (E2; 5 microg) into young female mice 21 days after DTM implantation increased, 24 h later, CK activity in the newly formed ossicles by approximately 60%, whereas injection of dihydrotestosterone (DHT; 50 microg) had no effect on CK activity. In contrast, in male mice, DHT but not E2 increased CK activity in the ossicles by approximately 50%. This sex-specific response was abolished in gonadectomized mice resulting in a similar response of the ossicles to both E2 and DHT. When DTM was implanted into vitamin D- deficient female mice, there was a lower basal CK activity and a significantly diminished response to E2 in the newly formed bone tissues. When BM, which contains mesenchymal and stromal cells and committed osteoprogenitor cells, was transplanted into 6-week-old intact or gonadectomized female or male mice, the response of the newly formed bone ossicles, 21 days after transplantation, to E2 or to DHT was according to the gender of the donor. Bone formed from BM obtained from female mice responded to E2 only and those formed from male BM responded to DHT only. Ossicles developed from BM obtained from gonadectomized mice showed lack of response to either gonadal steroid. Furthermore, only approximately 25% of the BM transplants obtained from castrated (CAST) male donors developed into ossicles. Ossicles formed from BM obtained from vitamin D-deficient female donors showed lack of response to gonadal steroids. These findings suggest that the manipulation of the hormonal milieu in early stages of the differentiation sequence of bone cells modifies the subsequent selective responsiveness of the developing bone tissue to gonadal steroids.

24,25-Dihydroxyvitamin D 3↗

PubMed1996

Osteogenic growth peptide increases blood and bone marrow cellularity and enhances engraftment of bone marrow transplants in mice.

The osteogenic growth peptide (OGP) was characterized recently in regenerating bone marrow (BM) and normal serum. In vitro, the OGP regulates stromal-cell proliferation and differentiated functions. In vivo, an increase in serum OGP accompanies the osteogenic phase of postablation BM regeneration. The present results in normal mice show that OGP induces a balanced increase in WBC counts and overall BM cellularity. In mice receiving myeloablative irradiation and syngeneic or semiallogeneic BM transplants, OGP stimulates hematopoietic reconstruction and doubles the survival rate; these effects are dependent on initiating the OGP administration before irradiation. Chimerism measurements in semiallogeneic graft recipients suggest no preferential effect of OGP on residual host cells. The data implicate OGP in the acceleration of hematopoiesis secondary to expansion of the stromal microenvironment and/or enhancement of stroma-derived signals to stem cells. The low-dose effectiveness of OGP is explained by the demonstration of an autocrine positive feedback loop that together with the OGP-binding protein sustains high serum levels of the peptide. A potential OGP-based treatment in combination with chemoradiotherapy is attractive because of the OGP-induced balanced multi-lineage enhancement of hematopoiesis and possible replacement of expensive recombinant cytokines by a readily synthesized peptide.

Animals↗

PubMed1995

Growth modulation and differentiation of acute myeloid leukemia cells by jaspamide.

We have examined the effect of Jaspamide, a peptide isolated from the marine sponge Hemiastrella minor, on in vitro proliferation and differentiation of leukemic cell lines and blast cells of three AML patients and compared it to that of cytosine arabinoside (ARA-C). The biological properties were studied in two complementary culture methods. The first is a clonogenic assay that supports colony formation in agar and reflects terminal divisions. The second is a suspension assay in which clonogenic cells increase exponentially and which reflects self-renewal. Jaspamide, at micromolar concentrations and in a dose-dependent manner, suppressed both primary colony formation in agar and the recovery of clonogenic cells from suspension culture in the investigated cell lines and in fresh blasts. Furthermore, Jaspamide was more effective in inhibiting clonogenic cells grown in suspension than primary colonies grown in agar. In addition, Jaspamide, similarly to ARA-C, was able to induce immunophenotypic maturation of leukemic cell lines (upregulation of CD14 and CD11 and downregulation of CD34 antigens). Our results indicate that Jaspamide significantly inhibits the self-renewal capacity of leukemic progenitors and may provide a new useful tool for the treatment of acute myeloid leukemia (AML) patients.

Antigens, CD↗

PubMed1995

Sensitivity of hematopoietic progenitors of acute myeloblastic leukemia to new compounds derived from marine organisms.

Results of chemotherapy in acute myeloid leukemia (AML) have improved slowly or not at all in the last decade. We evaluated the effect of Eilatin and Norsegoline, two new aromatic alkaloids derived from the Red Sea purple tunicate Eudistoma sp., on in vitro proliferation and differentiation of leukemic cell lines and blast cells of three AML patients. These biological properties were studied in two complementary culture methods. The first is a clonogenic assay that supports colony formation in agar and reflects terminal divisions. The second is a suspension assay where clonogenic cells increase exponentially and reflects self-renewal. Eilatin and Norsegoline, at micromolar concentrations, suppressed, in a dose-dependent manner, both primary colony formation in agar and the recovery of clonogenic cells from suspension culture in the investigated cell lines and in fresh blasts. Furthermore, both alkaloids were more effective in inhibiting clonogenic cells grown in suspension than primary colonies grown in agar. In addition, these agents were able to induce immunophenotypic maturation of leukemic cell lines (upregulation of CD14 and CD11 and down-regulation of CD34 antigens). Our results indicate that Eilatin and Norsegoline significantly inhibit self-renewal capacity of leukemic progenitors and may provide a useful new tool for the treatment of AML patients.

Alkaloids↗

PubMed1994

Stromal cell-mediated stimulation of osteoclastogenesis.

In the bone marrow microenvironment, stromal cells or their products are known to regulate proliferation and differentiation of hematopoietic stem cells. The purpose of this investigation was to characterize stroma-mediated effects of differentiation-inducing factors on osteoclastogenesis in defined murine cultures. Hematopoietic progenitors (derived from long-term bone marrow cultures, LTBMCs) were cocultured with cloned stromal cell lines to demonstrate the indirect effects of various differentiation-inducing factors. Osteoclastogenesis was compared in three murine marrow systems (whole bone marrow, progenitors cultured alone, and cocultures of progenitors with stromal cell lines) by analysis of multinuclearity and tartrateresistant acid phosphatase (TRAP) activity. The cultures were treated for two weeks with murine recombinant GM-CSF (5 U/ml), 1,25-dihydroxyvitamin D3 (10(-8) M), or parathyroid hormone (PTH, 10(-8) M). In whole bone marrow cultures, osteoclast differentiation was stimulated by GM-CSF, PTH and 1,25-dihydroxyvitamin D3. With progenitors alone, only GM-CSF promoted osteoclastogenesis. Each agent stimulated osteoclastogenesis in cocultures of progenitors with a stromal cell line (GBLneo'). Thus, the coculture system is a partially defined model for whole bone marrow cultures. In contrast, progenitors that were cocultured with a stromal cell line derived from an osteopetrotic op/op mouse failed to differentiate in the presence of PTH or 1,25-dihydroxyvitamin D3. These results indicate that stimulation of osteoclastogenesis by PTH or 1,25-dihydroxyvitamin D3 is mediated indirectly through factors present in normal marrow stromal cells and that an osteopetrotic stromal cell line failed to support differentiation.

Animals↗

PubMed1992

Origin of stromal cells associated with osteoclast recruitment in s.c. implants of bone particles in chimeric mice.

Subcutaneous implantation of devitalized bone particles (BPs) in mice elicits a fibrovascular response with subsequent differentiation of multinucleated osteoclast-like cells. In bone marrow, stromal cells are known to play important roles in controlling hematopoiesis. Similarly, the stromal cells in the initial reaction to BPs may take part in supporting subsequent osteoclast recruitment and differentiation within the implants. Cross-gender chimeric mice were used to allow determination of whether these stromal cells were derived from local tissue or from hematopoietic stem cells. In radiation-chimeric mice, there was a 7-day delay in stromal recruitment and osteoclastic differentiation. Therefore cultures were established from the stromal tissue elicited 11 days after implantation, prior to osteoclastogenesis. Analysis of Y-chromatin DNA from these lines demonstrated that the majority (97%) of the lines were of recipient origin. It is possible that these fibroblast-like cells migrate to the site of BP implantation and play a role in the initiation of osteoclast development. This model can be used to define cellular interactions in osteoclastogenesis.

Animals↗

PubMed1991

Effect of exogenous recombinant human granulocyte and granulocyte-macrophage colony-stimulating factor on neutrophil function following allogeneic bone marrow transplantation.

Functional activity of peripheral blood granulocytes was assessed in seven patients and in their normal donors following allogeneic bone marrow transplantation (BMT). Functions studied included superoxide generation (O2-), intracellular killing of Staphylococcus aureus, phagocytosis, and killing of Candida albicans. Neutrophils were tested following preincubation with 300 pM granulocyte-macrophage colony-stimulating factor (GM-CSF), 1.2 nM granulocyte colony-stimulating factor (G-CSF), or buffered solution (diluent) as control. Our data indicate that following BMT, both recipients and their normal donors show GM-CSF- and G-CSF-induced increases in: 1) O2- production in response to fMet-Leu-Phe (fMLP), 2) killing of S. aureus, and 3) phagocytosis of C. albicans. In two patients that showed low candidacidal activity, GM-CSF and G-CSF markedly enhanced the cytotoxic activity of the cells. Our studies indicate that GM-CSF and G-CSF increase "oxygen-dependent" oxidative activities in neutrophils from BMT recipients and their normal donors and enhance the antimicrobial activity of the cells.

Adult↗

PubMed1990

Enhanced resistance of bone marrow transplanted mice to bacterial infection induced by recombinant granulocyte-macrophage colony-stimulating factor.

The in vivo effect of recombinant murine granulocyte-macrophage colony stimulating factor (rGM-CSF) on the resistance of mice to bacterial infection and on the number and function of neutrophils was studied in lethally irradiated mice transplanted with syngeneic bone marrow cells. Bone marrow transplanted (BMT) mice were injected intraperitoneally with 150 ng rGM-CSF or buffer solution (diluent) twice daily for 18 consecutive days. Total neutrophil recovery from the peripheral blood and the number of neutrophils mobilized into the peritoneal cavity were accelerated in rGM-CSF-treated recipients. Peritoneal neutrophils isolated from mice treated with rGM-CSF exhibited primed superoxide generation (O2-) after in vitro stimulation with suboptimal concentrations of phorbol myristate acetate (PMA), as compared with control mice (treated with diluent). No additional increase in O2- production occurred upon in vitro incubation of these cells with rGM-CSF. The protective activity of rGM-CSF was examined in mice injected with Salmonella typhimurium. There was a 44- and 9-fold increase in the number of S typhimurium at 96 hours postinfection in the spleen and liver, respectively, of control mice, as compared with rGM-CSF-treated mice, after a single injection of the bacteria (3 X 10(7) per mouse). All the untreated control mice died within 14 days postinoculation (1 X 10(7) bacteria per mouse), whereas 35% of the mice treated with rGM-CSF remained alive for more than 30 days postinfection. These findings support the concept that increased granulopoiesis and enhanced functional activity of phagocytic cells is induced by rGM-CSF and is responsible for enhanced resistance of BMT mice to bacterial infection.

Animals↗

PubMed1990

Stimulation of myeloid colony development elaborated by colony forming cells--fibroblasts from rat developing ossicles.

Subcutaneous implantation of demineralized bone matrix in rats results in endochondral bone formation and bone-marrow development. The cascade of events leading to this process occurs following the accumulation of mesenchymal cells with colony forming cell fibroblasts (CFC-F) potential in the implanted area, a process which commences already 72 h post implantation. It is demonstrated herein that CFC-F from various stages of ossicle development (days, 3, 7, 10, 14 or 18) stimulate hemopoiesis to the same extent as judged by the number of granuloid-macrophage-progenitors (CFU-GM), developed as hemopoietic colonies, and by the ratio of granuloid to macrophagic colonies. High concentrations of CFC-F, however, tend to diminish the stimulatory capacity. Prostaglandin E, CFU-GM, CFC-F, ossicle, growth factors, microenvironment, hemopoiesis, development.

Animals↗

PubMed1989

Some recombinant human cytokines stimulate glycosaminoglycan synthesis in human synovial fibroblast cultures and inhibit it in human articular cartilage cultures.

Recombinant human cytokines were compared for their effects on glycosaminoglycan (GAG) synthesis in human synovial fibroblast cultures and human articular cartilage explant cultures. In fibroblast cultures, recombinant human interleukin-1 alpha (rHuIL-1 alpha), rHuIL-1 beta, and recombinant human tumor necrosis factor alpha (rHuTNF alpha) stimulated hyaluronic acid (HA) production and, to a lesser extent, sulfated GAG production, while recombinant human gamma-interferon did not have a significant effect. Half-maximal stimulation of HA by rHuIL-1 beta was 0.14 pM, while stimulation for rHuIL-1 alpha and rHuTNF alpha was 1.6 pM and 32 pM, respectively. Indomethacin (10 micrograms/ml) had no influence on HA stimulation by cytokines, while hydrocortisone (2-10 micrograms/ml) caused a significant reduction. In articular cartilage cultures, the cytokines inhibited production of sulfated GAGs. The activity of rHuIL-1 beta was greater than that of rHuIL-1 alpha (half-maximal inhibition at 0.71 pM and 4.7 pM, respectively) and both were considerably more active than rHuTNF alpha; gamma-interferon again had no significant effect. Neither indomethacin nor hydrocortisone influenced cytokine-induced inhibition by either rHuIL-1 preparation. These studies indicate that cytokines released during an inflammatory process may affect GAG synthesis in human joint tissues and may have opposite effects on GAG synthesis in different types of connective tissues.

Biological Factors↗

PubMed1989

Antibody to Mol abrogates the increase in neutrophil phagocytosis and degranulation induced by granulocyte-macrophage colony-stimulating factor.

We studied the ability of the human hemopoietic growth factors, granulocyte-macrophage colony-stimulating factor (GM-CSF) and granulocyte colony-stimulating factor (G-CSF) to activate polymorphonuclear neutrophils (PMN) for increased phagocytosis of opsonized Candida albicans and enhanced degranulation. Exposure of neutrophils to these two growth factors resulted in an increased number of Candida phagocytosed. Pretreatment of the neutrophils with the monoclonal antibody anti-Mol abrogated the enhanced phagocytosis associated with GM-CSF priming but not that of G-CSF primed PMN. In examining the effect of these two colony-stimulating factors (CSFs) on neutrophil degranulation we found that GM-CSF induced enhanced release of lysozyme from cytochalasin-treated PMN in the presence of Candida; however, G-CSF did not. The effect of GM-CSF on lysozyme release was abrogated by anti-Mol antibody. These data suggest that GM-CSF and G-CSF prime PMN for certain enhanced functional activities by distinct mechanisms. The differential effect of the CSFs on neutrophil degranulation may relate to the more common inflammatory symptoms seen when GM-CSF is used clinically as compared to the experience with G-CSF.

Antibodies, Monoclonal↗

PubMed1989

Biological properties in vitro of a combination of recombinant murine interleukin-3 and granulocyte-macrophage colony-stimulating factor.

The effect of recombinant murine interleukin-3 (rIL-3) and recombinant murine granulocyte-macrophage colony-stimulating factor (rGM-CSF) on in vitro murine myeloid progenitor cell (CFU-C) growth and on the function of murine resident peritoneal macrophages was investigated. Both rIL-3 and rGM-CSF are known to support the growth of CFU-C and, when combined, were found to act synergistically to induce the development of an increased number of CFU-C. The distribution pattern of myeloid colonies in the presence of these two growth factors was in general similar to that in the presence of rGM-CSF alone. Both rGM-CSF and rIL-3 enhanced the phagocytosis of Candida albicans (CA) by mature macrophages producing an increase in the percentage of phagocytosing cells as well as an increase in the number of yeast particles ingested per cell. No additive effect on the phagocytosis was observed when the two growth factors were added concurrently. rGM-CSF, but not rIL-3, enhanced the killing of CA by macrophages. This killing was inhibited by scavengers of oxygen radicals.

Animals↗

PubMed1989

Induction of murine macrophage fungal killing by interleukin 3.

The effect of recombinant interleukin 3 (IL-3) on the function of murine resident peritoneal macrophages was investigated. IL-3 enhanced the phagocytosis of Candida pseudotropicalis and Candida albicans and enhanced killing of the former. The enhanced killing is inhibited by scavengers of oxygen radicals, suggesting that IL-3 primes macrophages for enhanced oxidative metabolism in response to Candida.

Animals↗

PubMed1988

The effect of 13-cis retinoic acid on hematopoiesis in human long-term bone marrow culture.

The modulatory effect of 13-cis retinoic acid (RA) on the growth, differentiation and function of hematopoietic cells in human long-term cultures was studied. RA (5 X 10(-8) M) induced enhancement of myeloid progenitor cell growth in the non-adherent layer throughout 6 weeks of incubation while it did not affect the number of myeloid progenitors in the adherent layer. The vitamin did not alter the differentiation pattern of colony forming unit-culture (CFU-C). The addition of RA to cultures for 5 weeks did not alter the cellular composition of the adherent layer. Prolonged exposure of hematopoietic cells to RA did not affect the functional activity of neutrophils and macrophages, i.e. the cells were active in phagocytosing Candida albicans (CA).

Bone Marrow Cells↗

PubMed1987

The effect of 1,25-dihydroxyvitamin D3 on hematopoiesis in long-term human bone marrow cultures.

The modulatory effect of 1,25-dihydroxyvitamin D3 (vit D) on the growth of myeloid progenitors and on the composition of the stromal layer in human bone marrow long-term cultures was studied. Vit D (2 X 10(-8) M) caused an enhancement in myeloid progenitor cell (CFU-C) growth in the nonadherent and adherent layers during the entire 5-week incubation period. The vitamin did not alter the differentiation pattern of CFU-C (monocyte-macrophage progenitors CFU-M, granulocytic progenitors CFU-G, or monocyte-granulocyte progenitors CFU-GM). Vit D caused a marked increase in the percentage of lipid-containing cells in the adherent layer and an increase in the number of cells that specifically bound My4 monoclonal antibody (McAb), that reacted positively to fluoride-sensitive alpha-naphthyl acetate esterase, and that phagocytosed Candida albicans (CA). Concentrated supernatants harvested from control cultures showed significant levels of myeloid colony stimulating factor (CSF) activity. The addition of vit D to cultures for 5 weeks did not alter CSF levels. These results suggest that vit D may play a role in hematopoiesis by acting directly on the progenitor cells or via the stromal cell production of stimulatory factor(s).

Bone Marrow Cells↗

PubMed1987

Enhanced reconstitution of hematopoietic organs in irradiated mice, following their transplantation with bone marrow cells pretreated with recombinant interleukin 3.

Lethally irradiated C3H/eb mice were injected with syngeneic bone marrow cells that had been exposed for 4 h in vitro to purified bacterially synthesized interleukin 3 (rIL-3). Control mice were injected with cells exposed to incubation medium only. Mice injected with rIL-3-treated cells exhibited, on day 10 after transplantation an 8.2-fold and 2.7-fold increase in number of myeloid progenitors in their spleen and bone marrow, respectively, but the in vitro differentiation pattern of the myeloid progenitors was not affected. There was, however, an increase in the number of cells per individual in vitro myeloid colony (CFU-C) of the rIL-3-treated mice. The latter mice also showed a 1.6-fold increase in the number of splenic colony-forming units (CFU-S), a higher self-renewal capacity of hematopoietic progenitors, and a higher number of leukocytes in the peripheral blood. These results indicate that the injection into lethally irradiated recipients of bone marrow cells briefly pretreated in vitro with rIL-3 significantly enhances the reconstitution of their hematopoietic organs, and suggest that the in vitro pretreatment of bone marrow cells with appropriate stimulating factors could be useful in bone marrow transplantation.

Animals↗