A lethal myeloproliferative syndrome in mice transplanted with bone marrow cells infected with a retrovirus expressing granulocyte-macrophage colony stimulating factor.

Murine bone marrow cells infected with a novel recombinant retrovirus, MPZen(GM-CSF), were engrafted into lethally irradiated recipients. The transplanted animals developed extremely high circulating levels of GM-CSF (up to 3 x 10(5) units/ml), and greatly elevated peripheral nucleated cell counts (up to 110 x 10(6) per ml). Their haemopoietic tissues contained GM-CSF proviral DNA and produced substantial levels of GM-CSF. The mice died within 4 weeks of transplantation with extensive neutrophil and macrophage infiltration of the spleen, lung, liver and peritoneal cavity and significant infiltration of both heart and skeletal muscle by neutrophils, macrophages and eosinophils. The thymus and lymph nodes were deficient in lymphoid cells. No disease occurred when infected cells from haemopoietic tissues of the primary transplanted animals were injected into normal or sub-lethally irradiated mice. Dysregulated GM-CSF expression by haemopoietic cells thus produces a fatal albeit non-neoplastic myeloproliferative syndrome.     

Increased fibroblast colony stimulating activity (F-CSA) in serum of myeloproliferative disorders

Sera of patients with primary myelofibrosis (PMF), primary thrombocythemia (PT), polycythaemia vera (PV) and chronic myeloid leukemia (CML) contained a significantly increased F-CSA (or F-CSAs) compared to those of normal subjects and patients with secondary thrombocytosis (ST). This F-CSA was heat sensitive and had the capacity to promote both proliferation and maturation of normal marrow fibroblast colony-forming cells (CFU-F). This F-CSA seemed to be different from human platelet derived growth factor (PDGF), tumor necrosis factor (TNF) and fibroblast growth factor (FGF) from bovine brain. This F-CSA might be of importance in the pathogenesis of bone marrow fibrosis in myeloproliferative disorders.     

The myeloproliferative sarcoma virus causes transformation or erythroid progenitor cells in vitro

The myeloproliferative sarcoma virus induces spleen focus formation in vivo and transforms fibroblasts in vitro. We showed in this study that in vitro infection of spleen or bone marrow cells from susceptible mice with the myeloproliferative sarcoma virus leads to the formation of erythroid bursts. Under optimal conditions erythroid bursts formed in the absence of added erythropoietin, but the addition of as little as 0.05 U of erythropoietin per ml to infected cultures resulted in a significant increase in numbers of erythroid bursts and the proportion of hemoglobinized cells. A comparison of the kinetics of burst formation and the size of the induced bursts with those induced with Friend virus suggested that either sarcoma virus such as the myeloproliferative sarcoma virus or the target cells for the two viruses were not the same. Density characterization and heat lability studies indicated that the increased erythroid proliferation in vitro was a virus-induced event, but the possibility that the induced erythroid burst formation is mediated via interaction with a nonerythroid target cell and subsequent release of a soluble factor cannot be ruled out.     

Effect of a corpuscular polyvalent Pseudomonas aeruginosa vaccine on the proliferation and differentiation of hematopoietic stem cells and erythropoiesis

P. aeruginosa corpuscular polyvalent vaccine stimulates hematopoiesis in sublethally stimulated mice. The stimulating effect is dose-dependent. The most effective method of immunization is the intravenous injection of the vaccine. The degree to which the stimulation of hematopoiesis is manifested varies in different strains of mice. The stimulation of hematopoiesis is not linked with an increase in the content of erythropoietin. P. aeruginosa polyvalent corpuscular vaccine and monovaccine, prepared from P. aeruginosa strain 1313 and incorporated into the polyvalent vaccine, protect lethally irradiated mice in the postradiation survival test.     

Thiamphenicol induced bone marrow suppression as a therapy of myeloproliferative diseases

Sixteen patients, suffering from myeloproliferative diseases (9 polycythaemia vera, 7 primary thrombocythaemia) and 20 control subjects were treated for 14 days with 1 g of thiamphenicol per day. The effect of 40 treatment cycles was studied. The regimen resulted in lowering the haemoglobin values by 4.8% in controls (p greater than or equal to 0.001) and patients (p greater than or equal to 0.01); the reticulocyte count dropped 43% in the patient group (p greater than or equal to 0.01) and 32% in the controls (p greater than or equal to 0.05); the thrombocyte count was decreased 42% (p greater than or equal to 0.0001) vs 29% (p greater than or equal to 0.0001) in the control group. The administration of 1 g/day of thiamphenicol for a 14 day period reduced the myelopoietic activity by 40%. The decrease of all values was statistically significant. After discontinuation of thiamphenicol therapy the haematological parameters returned to the initial values within 1-2 months. The myelodepressant activity of thiamphenicol may therefore be applied to the therapy of the myeloproliferative diseases in order to reduce the risk of spontaneous haemorrhages and thrombosis.     

Multilineage hematopoietic disorders induced by transplantation of bone marrow cells expressing the v-fms oncogene

Mouse bone marrow cells infected with a helper-free retrovirus containing v-fms were engrafted into lethally irradiated mice. Dominant provirus-positive clones emerged in the spleens of some recipients within 1 month. When spleen cells were transplanted into lethally irradiated secondary recipients, clonal erythroleukemias or B cell lymphomas expressing the v-fms-coded glycoprotein developed. Other secondary recipients repopulated by “unmarked” progenitor cells or by cryptic provirus-positive precursors present in the spleens of the same donor mice did not develop disease; thus cells expressing v-fms did not invariably have a proliferative advantage after transplantation. Several primary engrafted recipients developed myeloproliferative disorders that were provirus-positive without evidence of clonality. Although expression of the c-fms product (CSF-1 receptor) is normally restricted to cells of the mononuclear phagocyte series, the v-fms-coded glycoprotein can contribute to proliferative abnormalities of multiple hematopoietic lineages.     

KINETICS OF ERYTHROPOIETIN STIMULATED PROLIFERATION OF ERYTHROID PROGENITORS IN THE SPLEEN

The effect of RBC transfusion and erythropoietin (EPO) on the proliferation of immature erythrocyte progenitors was studied in the spleens of RBC transfused, lethally irradiated mice injected with bone marrow. Transfusion decreased expansion of the progenitors and slowed their proliferation: the mean cycle time as measured by per cent labelled mitosis (PLM) on the third day after injection of bone marrow was 10.7 hr in transfused as compared to 5.6 hr in non-transfused mice. One injection of five units of erythropoietin on day 2 decreased the mean cycle time to 7.3 hr in transfused mice and increased expansion of the progenitor cells. The effects of erythropoietin on cell proliferation were prompt: a significant increase of incorporation of ³H-TdR into DNA occurred within 2 hr of injection. Erythroblasts were absent from the spleens of transfused, irradiated bone marrow injected mice; however, erythroblasts appeared by 72 hr and 48 hr following EPO injection either 2 days or 5 days after transplantation respectively. Increased uptake of radioactive iron in spleen after erythropoietin injection preceded the appearance of erythroblasts by 2 and 1 days when erythropoietin was injected either 2 or 5 days after marrow transplantation respectively. The increase in cellular proliferation induced by erythropoietin in transfused irradiated mice injected with bone marrow equivalent to 0.35 femoral shaft was manifested as an increase of the total DNA content in the spleen by 119 μg (11.9 × 10⁶ cells) within 48 hr of injection. The cellular increment produced by EPO injection on day 5 to mice given 0.05 femoral shaft consisted mainly of undifferentiated mononuclear cells, most of which were labelled, with erythroblasts comprising only one quarter of the increment. Erythropoietin inactivated by mild acid hydrolysis failed to increase cellular proliferation.     

The effect of hypertransfusion on the growth of mouse foetal liver cells transplanted into irradiated, adult recipients: failure to detect a differential effect between cells from early and late foetuses

Erythropoiesis can be reinstated in lethally irradiated mice by transplantation of adult bone marrow or liver cells from foetuses at any stage of gestation beyond the eleventh day. Hypertransfusion of the recipients abolishes erythropoiesis resulting from the transplants, even when the transplants are derived from foetuses at a very early stage of development. This suggests that erythropoietin is necessary for the successful growth of these early foetal transplants, at least in the environment of the irradiated recipient. These results are at variance with an earlier report on the susceptibility of early foetal liver transplants to suppression by hypertransfusion.     

Expression of the surface membrane receptors of neutrophils in myeloproliferative diseases

For 147 patients with myeloproliferative diseases, a study was made of the expression of Fc-receptors to immunoglobulins IgC, IgA, and that of FcH-receptor and receptors to C3-components of the complement in peripheral blood neutrophils. The data obtained show the lower level of neutrophils having membrane receptors in patients with acute myeloblastic leukemia and chronic granulocytic leukemia at the stage of blast transformation. A decrease in expression of membrane receptors of neutrophils was shown in patients with chronic granulocytic leukemia and benign subleukemic myelosis. The finding of a higher level of neutrophils having surface receptors revealed in patients with real polycythemia is close to the data obtained in the study of expression of membrane receptors in patients with chronic myeloproliferative diseases and healthy persons.     

Abnormalities of platelet aggregation in chronic myeloproliferative disorders

A large variety of platelet dysfunctions has been described in chronic myeloproliferative disorders. These abnormalities may be due to deficiency of platelet granules, arahidonic acid metabolism defects or platelet membrane glycoproteins abnormalities. In this study we intend to detect the incidence of platelet function defects in 76 patients with various types of chronic myeloproliferative disorders. The platelet activity was studied in vitro by measuring platelet aggregation in response to ADP, epinephrine, collagen, arachidonic acid and ristocetin. These results were subsequently correlated with bleeding time and clinical aspects (bleeding or thrombosis). We found complex changes in platelet response with all agonists, in varied proportions. These abnormalities include absent, decreased or abnormal platelet aggregation response. In a few cases we found a markedly decreased, almost absent platelet response to all agonists while in some patients a normal platelet aggregation was noted. The correlation between these results and template bleeding time, thrombotic or hemorrhagic events and the type of diseases was difficult to establish and sometimes conflictual. Despite this fact, we consider that investigating platelet aggregation may be useful not only for the assesment of the hemostatic balance in chronic myeloproliferative disorders but also for a better insight into cell abnormalities occuring in these pathologic conditions.     

A fluorescent dye which recognizes mature peripheral erythrocytes of myeloproliferative disorders

Based on the previous finding that erythrocytes from patients with chronic myelogenous leukemia stain with the fluorescent dye merocyanine 540, erythrocytes from patients with other myeloproliferative disorders were examined for their ability to bind the membrane probe. As assessed by both fluorescence staining and a quantitative dye removal assay, all samples of erythrocytes from patients with chronic myelogenous leukemia, polycythemia vera, myelofibrosis with myeloid metaplasia and essential thrombocythemia bound more dye than did erythrocytes from normal, healthy individuals. Erythrocytes from three of six patients with acute myelogenous leukemia also showed increased affinity for the dye. In contrast, erythrocytes from three patients with acute lymphocytic leukemia and one with unclassifiable leukemia bound only normal amounts of dye. The procedures described may be useful as a supplemental aid to diagnosis of myeloproliferative disorders or for investigation of hematological diseases where multilineage involvement is suspected.     

Conditional MLL-CBP targets GMP and models therapy-related myeloproliferative disease

Chromosomal translocations that fuse the mixed lineage leukemia (MLL) gene with multiple partners typify acute leukemias of infancy as well as therapy-related leukemias. We utilized a conditional knockin strategy to bypass the embryonic lethality caused by MLL-CBP expression and to assess the immediate effects of induced MLL-CBP expression on hematopoiesis. Within days of activating MLL-CBP, the fusion protein selectively expanded granulocyte/macrophage progenitors (GMP) and enhanced their self-renewal/proliferation. MLL-CBP altered the gene expression program of GMP, upregulating a subset of genes including Hox a9. Inhibition of Hox a9 expression by RNA interference demonstrated that MLL-CBP required Hox a9 for its enhanced cell expansion. Following exposure to sublethal gamma-irradiation or N-ethyl-N-nitrosourea (ENU), MLL-CBP mice developed myelomonocytic hyperplasia and progressed to fatal myeloproliferative disorders. These represented the spectrum of therapy-induced acute myelomonocytic leukemia/chronic myelomonocytic leukemia/myelodysplastic/myeloproliferative disorder similar to that seen in humans possessing the t(11;16). This model of MLL-CBP therapy-related myeloproliferative disease demonstrates the selectivity of this MLL fusion for GMP cells and its ability to initiate leukemogenesis in conjunction with cooperating mutations.     

Effect of erythrocyte breakdown products on mast cells and erythropoietin formation]

Experiments were conducted on CBA mice and albino rats. A study was made of the effect of erythrocyte destruction products (EDP) on the content of hemopoietic colony-forming units (CFU), differentiation of stem cells and the erythropoietin production. It was shown that 3 or 4 EDP injections to normal mice or to lethally irradiated (1000 rad) mice after the transplantation of bone marrow cells caused no changes in the CFU level of stem cells differentiation. In case of a daily (for 3 days) administration of EDP to mice before the irradiation (1000 rad) and bone marrow transplantation there was observed an increase of the colonies count in the recipients' spleen on account of the erythroid colonies. EDP injection caused no changes in the erythropoietic activity of the blood serum. A possible role of erythrocyte destruction products in the mechanism of erythropoiesis autoregulation is discussed.     

Monoclonal gammopathy in chronic myeloproliferative disorders

The incidence of monoclonal gammopathy in 61 patients with chronic myeloproliferative disorders (CMPD) was studied. The distribution of patients among the CMPD subgroups was: chronic myelocytic leukemia, 24 patients; myelofibrosis, 11; polycythemia vera, 15; essential thrombocythemia, 7; unclassified MPD, 4 patients. Monoclonal gammopathy was found in 5 patients (8.2%). Two of these patients (1 IgA/k and 1 IgM/k) had myelofibrosis and 3 (2 IgG/k and 1 IgG/lambda) polycythemia vera. The presence of monoclonal gammopathy indicates an involvement of the lymphoplasmatic system in CMPD.     

Bcr-Abl with an SH3 deletion retains the ability To induce a myeloproliferative disease in mice, yet c-Abl activated by an SH3 deletion induces only lymphoid malignancy

The bcr-abl oncogene plays a critical role in the pathogenesis of chronic myelogenous leukemia (CML). The fusion of Bcr sequences to Abl constitutively activates the Abl protein tyrosine kinase. We have recently shown that expression of Bcr-Abl in bone marrow cells by retroviral transduction efficiently induces in mice a myeloproliferative disease resembling human CML and that Abl kinase activity is essential for Bcr-Abl to induce a CML-like myeloproliferative disease. However, it is not known if activation of the Abl kinase alone is sufficient to induce a myeloproliferative disease. In this study, we examined the role of the Abl SH3 domain of Bcr-Abl in induction of myeloproliferative disease and tested whether c-Abl activated by SH3 deletion can induce a CML-like disease. We found that Bcr-Abl with an Abl SH3 deletion still induced a CML-like disease in mice. In contrast, c-Abl activated by SH3 deletion induced only lymphoid malignancies in mice and did not stimulate the growth of myeloid colonies from 5-fluorouracil-treated bone marrow cells in vitro. These results indicate that Bcr sequences in Bcr-Abl play additional roles in inducing myeloproliferative disease beyond simply activating the Abl kinase domain and that functions of the Abl SH3 domain are either not required or redundant in Bcr-Abl-induced myeloproliferative disease. The results also suggest that the type of hematological neoplasm induced by an abl oncogene is influenced not only by what type of hematopoietic cells the oncogene is targeted into but also by the intrinsic oncogenic properties of the particular abl oncogene. In addition, we found that DeltaSH3 c-Abl induced less activation of Akt and STAT5 than did Bcr-Abl, suggesting that activation of these pathways plays a critical role in inducing a CML-like disease.     

Decreased bone marrow iron in chronic granulocytic leukaemia: a consistent finding not reflecting iron deficiency

The iron status of 50 patients with Ph'-positive chronic granulocytic leukaemia (CGL) was evaluated at diagnosis by means of bone marrow and blood studies. A decreased or absent iron in semiquantitative estimation on bone marrow smears was observed in 92% of patients, and 88% had a low sideroblast score. In contrast, normal Hb and serum iron concentrations were found in the majority of cases, and only two out of the 50 patients displayed a decreased serum ferritin. To ascertain whether the bone marrow pattern of iron depletion could be due to an expansion of the red cell mass, the latter parameter was measured by isotopic methods in a subgroup of 11 patients. Normal or slightly increased values were obtained in all cases. We conclude that absent or decreased marrow iron is a common feature in the chronic phase of CGL, that generally does not reflect true iron deficiency. Since such a finding is also usual in polycythaemia vera and idiopathic myelofibrosis, it should be included among the features shared by the chronic myeloproliferative disorders.     

骨髓移植小鼠二甲基亚硝胺肝纤维化模型的建立

目的构建绿色荧光蛋白(GFP)标记骨髓细胞的小鼠,并复制其二甲基亚硝胺(DMN)肝纤维化模型。方法 ICR雄性小鼠32只,随机分为正常组6只和移植组26只。移植组接受致死量γ射线照射后,经尾静脉输入GFP转基因小鼠的骨髓细胞;正常组不进行照射和移植,仅尾静脉注射等量生理盐水。两个月后制备血涂片,观察移植组造血重建情况,造血重建动物再分为对照组和造模组,造模组用DMN按每次10mg/kg体重腹腔注射制备肝纤维化模型,隔日一次,正常组和对照组给予等量生理盐水。设染毒后3周和4周两个时间观察点,生化法测定肝功能;Jamall法检测肝组织羟脯氨酸含量;HE染色及天狼猩红染色观察肝组织炎症、坏死及纤维组织增生情况;GFP免疫荧光组织化学观察骨髓源性细胞在肝脏的归巢特点。结果骨髓移植两个月后,移植组外周血中出现满视野GFP+细胞。与正常组比较,两个时间观察点造模组肝功能(ALT、AST、Alb及T.Bil)均明显异常(P<0.05),肝组织羟脯氨酸含量显著增高(P<0.05),造模3周末肝组织出血性坏死,有炎性细胞浸润,但尚未形成完全的纤维间隔;造模4周末肝组织炎症、坏死程度加重,可见完全的纤维间隔,在DMN造模动物肝组...     

In vivo natural antitumor resistance against murine EL-4 lymphoma cells in lethally irradiated syngeneic C57Bl/6 mice

Natural resistance has been detected in lethally irradiated C57Bl/6 (B6) mice inoculated intravenously with the ascites form of a syngeneic B6 leukemia. EL-4 cells were injected into lethally irradiated (800 R) B6 mice and tumor cell proliferation was evaluated by 125IUdR uptake in different organs 4 days after the challenge. Differential growth of lymphoma cells was observed when young mice were injected as compared with older mice and when mice were treated with agents known to interfere with natural resistance (e.g., poly(I:C), FLV-P, carrageenan, cyclophosphamide, high doses of irradiated cells). Similar results were obtained by measuring rapid clearance of 125IUdR-labeled EL-4 cells from lungs of intact B6 mice. In vivo cold competition studies, employing EL-4 and several other tumor lines of the same or different haplotype, showed that only EL-4 and RBL-5 cells were capable of inhibiting syngeneic resistance against EL-4 tumor. On the contrary, YAC-1 lymphoma cells, the most susceptible target to natural killer-mediated cytotoxicity in vitro, did not compete. These results suggest that EL-4 cells express membrane determinants not detectable on normal H-2b parental bone marrow cells and are susceptible to natural resistance against hemopoietic tumor cells in lethally irradiated syngeneic B6 mice.     

The effect of storage and short term cultivation the proliferation of mouse bone marrow stem cells]

Suspension of stored and short-term cultured murine bone marrow cells was i. v. administered to lethally irradiated mice. We demonstrated that the cells still after 72 h of storing and 24 h of culture in liquid medium were capable of proliferation and on day 9 following transplantation could produce colony forming units in the spleens of lethally irradiated mice. We established the relative participation of individual types of cells in the recovery of haemopoiesis in the spleens.