UMLS:C0026986 - FACTA Search

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Query: UMLS:C0026986 (myelodysplastic syndrome)
14,926 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Levels of transforming growth factor-beta (TGF-beta) activity in the conditioned medium of blood lymphocytes of twelve patients with aplastic anemia (AA), nine patients with myelodysplastic syndromes (MDS) and five normal volunteers were investigated. We were able to observe growth inhibitory activity on porcine endothelial cells only after acidification of the materials. The growth inhibitory activity is neutralized by anti-TGF-beta antibody. It indicates that TGF-beta exists as a latent form in the conditioned medium. On the basis of growth inhibition assay, the mean level of TGF-beta production of MDS patients was estimated to be 188 +/- 199 pg/1 x 10(7) cells and that of normal volunteers was 668 +/- 314 pg/1 x 10(7) cells. In contrast, the lymphocytes of almost all of the AA patients failed to produce detectable amounts of TGF-beta. No correlation between TGF-beta levels and peripheral blood parameters could be detected. Stimulation of lymphocytes by phytohemagglutinin is known to increase the production of TGF-beta. Induction of TGF-beta production was also observed in AA (45% of normal controls). Possible roles of the decreased production of TGF-beta in the pathogenesis of AA were discussed.
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PMID:Decreased level of transforming growth factor-beta in blood lymphocytes of patients with aplastic anemia. 159 Oct 18

The paradox of myelodysplastic syndromes (MDS) which present with pancytopenias despite cellular bone marrows (BM) was investigated by conducting detailed studies of proliferation and apoptosis in 89 MDS patients. Our results demonstrated a rapid rate of both proliferation as well as apoptosis. Levels of three cytokines, tumor necrosis factor-alpha (TNF-alpha), transforming growth factor-beta (TGF-beta) and interleukin-1 beta (IL-1 beta) were measured in the same patients. High levels of TNF-alpha were found to correlate with high levels of apoptosis in 83 MDS patients (P = 0.0045). We propose a dual role for TNF-alpha (or other cytokines) in the pathogenesis of MDS. On the one hand, TNF-alpha induces apoptosis in the maturing cells causing pancytopenia while on the other, it stimulates the proliferation of the primitive progenitors accounting for the hypercellular BM frequently seen in MDS. A new model for MDS is presented. The initial abnormality probably affects a primitive hemopoietic progenitor which acquires a growth advantage leading to monoclonal hemopoiesis, which in turn makes these cells susceptible towards acquiring additional mutations and appearance of cytogenetically marked (or unmarked) clones. Cytokines such as TNF-alpha whose source is presently unknown, then contribute towards the clinical syndrome of pancytopenia and hypercellularity.
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PMID:Novel insights into the biology of myelodysplastic syndromes: excessive apoptosis and the role of cytokines. 876 10

Extensive apoptosis or programmed cell death (PCD) of both hematopoietic (erythroid, myeloid, megakaryocytic) and stromal cells in myelodysplastic syndromes (MDS) cancels the high birth-rate resulting in ineffective hematopoiesis and has been demonstrated as the probable basis for peripheral cytopenias in MDS by our group. It is proposed that factors present in the microenvironment are inducing apoptosis in all the cells whether stromal or parenchymal. To investigate this hypothesis further, bone marrow biopsies from 46 MDS patients and eight normal individuals were examined for the presence of three cytokines, tumor necrosis factor-alpha (TNF-alpha), transforming growth factor-beta (TGF-beta) and granulocyte macrophage-colony stimulating factor (GM-CSF) and one cellular component, macrophages, by the use of monoclonal antibodies immunohistochemically. Results showed the presence of TNF-alpha and TGF-beta in 41/46 and 40/46 cases of MDS respectively, while only 15 cases showed the presence of GM-CSF. Further a significant direct relationship was found between the degree of TNF-alpha and the incidence of PCD (p= 0.0015). Patients who showed high PCD also had an elevated TNF-alpha level. Thus, the expression of high amounts of TNF-alpha and TGF-beta and low amounts of the viability factor GM-CSF may be responsible for the high incidence of PCD leading to ineffective hematopoiesis in MDS. Future studies will be directed at attempting to reverse the lesion in MDS by using anti-TNF-alpha drugs such as pentoxifylline.
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PMID:Measurement of apoptosis, proliferation and three cytokines in 46 patients with myelodysplastic syndromes. 900 44

Increased angiogenesis is important in the pathophysiology of solid tumors. Recent studies show that angiogenesis and angiogenic factors play an important role in hematological malignancies. Both acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) are associated with a substantial increase in vascularity in the bone marrow as well as increased levels of various angiogenic factors including vascular endothelial growth factor (VEGF), basic fibroblast growth factor, angiogenin, angiopoietin-1, platelet-derived growth factor, hepatocyte growth factor, epidermal growth factor, tumor necrosis factor-alpha, and transforming growth factor-alpha and transforming growth factor-beta. Most of these angiogenic factors appear to be secreted by the neoplastic hematopoietic cells and appear to promote the growth and proliferation of the leukemic cells in an autocrine fashion. More importantly, angiogenic factors play a role in the clinical behavior and outcome of both AML and MDS. Despite significant overlap between MDS and AML in many aspects, higher levels of cellular VEGF and lower levels KDR are seen in MDS than in AML. Antiangiogenic therapy may play a role in AML and MDS and some differences in response may exist between MDS and AML.
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PMID:Angiogenesis in acute myeloid leukemia and myelodysplastic syndrome. 1181 14

Labeling index (LI), apoptosis, levels of 2 pro-apoptotic cytokines tumor necrosis factor-alpha (TNF-alpha) and transforming growth factor-beta(TGF-beta), and the number of monocyte/macrophage cells that are the likely source of the cytokines were simultaneously measured in plastic-embedded bone marrow (BM) biopsy sections of 145 patients with myelodysplastic syndromes (MDS). TNF-alpha was correlated with TGF-beta (P = .001) and with monocyte/macrophage cells (P = .003). Patients with excess blasts in their marrows had a higher TGF-beta level (P = .01) and monocyte/macrophage number (P = .05). In a linear regression model,TGF-beta emerged as the most significant biological difference between patients who have excess of blasts and those who do not (P = .01). We conclude that in addition to TNF-alpha, TGF-beta also plays a significant role in the initiation and pathogenesis of MDS, and that a more precise definition of its role will likely identify better preventive and therapeutic strategies.
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PMID:Biological significance of proliferation, apoptosis, cytokines, and monocyte/macrophage cells in bone marrow biopsies of 145 patients with myelodysplastic syndrome. 1199 58

Angiogenesis is critical for the clinical progression of haematopoietic malignancies and depends on angiogenic factors. Angiogenin is a powerful factor produced by neoplastic cells and host microenvironment. High levels of soluble angiogenin (sAng) correlate with a poor prognosis in patients affected by acute myeloid leukaemia and myelodysplastic syndromes, but no data are available on sAng in chronic myeloproliferative disorders (CMD). Therefore, in this study we investigated the clinical significance of the angiogenin in sera of patients with chronic myeloid leukaemia (CML) (n = 14) or essential thrombocythaemia (ET) (n = 20), and correlated them with those of soluble transforming growth factor-beta(1) (sTGF beta(1)). Enzyme-linked immunosorbent assay detected (P < 0.05) higher levels of sAng in CMD compared with healthy subjects (1026.74 +/- 464.60 pg/mL and 196.00 +/- 39.90 pg/mL, respectively). The highest levels of sAng were detected in CML patients (1349.23 +/- 549.55 pg/mL). Interestingly, CML patients who achieved haematological remission after interferon therapy showed circulating levels of angiogenin significantly (P < 0.05) decreased when compared with those at diagnosis. In ET patients, levels of angiogenin (889.34 +/- 267.66 pg/mL) and sTGF beta(1) (76.69 +/-6.08 pg/mL) were higher (P < 0.05) compared with healthy controls (57.93 +/- 19.39 pg/mL). No correlation was found between levels of sAng and levels of sTGF beta(1) or platelet count among ET patients. Our results show for the first time that elevated blood levels of angiogenin feature chronic myeloid malignancies, suggesting a role of angiogenin in the pathogenesis of these diseases.
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PMID:Levels of soluble angiogenin in chronic myeloid malignancies: clinical implications. 1512 20

This meeting was convened by Richard T. Silver, M.D. and co-chaired by Jerry L. Spivak, M.D. It was held from 16 to 18 October 2003 in New York City, New York, USA. Thirty-nine invited speakers from nine different countries participated in the conference. There were more than 350 attendees. There were formal presentations and discussions on biology, clinical aspects, and management of patients with these diverse bone marrow stem cell disorders linked by a variable progression to acute myeloid leukemia. Of considerable interest, a clinical symposium exclusively for patients was held the day preceding the meeting at which John Bennett, Tiziano Barbui, Richard Silver, Jerry Spivak, and Ayalew Tefferi spoke on various topics pertaining to these diseases. This proved to be highly informative to the patients who reported that they enjoyed the program immensely. This was sponsored by the Cancer Research & Treatment Fund, Inc. Representatives of the Myelodysplasia Foundation were also present. This meeting report provides a summary of five different sections prepared by one or more of the session chairs. The keynote address was given by Shahin Rafii (Cornell Medical Center). Most appropriately, this talk focused on the expression and activation of angiogenic factors which play a crucial role in the progression of both myeloproliferative disorders and myelodysplastic syndromes (MDS). Among the known factors, vascular endothelial growth tyrosine kinase receptors (VEGF-R1, R2, and R3) support proliferation, survival, and mobility. Rafii's team has demonstrated that these receptors are expressed on subsets of primary hematopoietic cells as well as leukemic cells. Some leukemic cells express both VEGF-A and VEGF-R2, resulting in the generation of an autocrine loop that supports survival and within the osteoblastic zone translocating these cells to the vascular enriched niche for receipt of molecular instructions required for proliferation and differentiation. A pathologic correlation can be seen in some patients with the identification of abnormal localization of immature precursors (ALIP) in the central portions of the medullary cavity. Misplaced megakaryocytes can release pro-fibrotic factors, including platelet derived growth factors and transforming growth factor-beta. Collectively, these data suggest that chronic disregulation of angiogenic factors alter the microenvironment dislocating marrow stem cells that force both proliferation and differentiation in varying degrees, contributing to these hematological disorders.
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PMID:The second international congress on myeloproliferative and myelodysplastic syndromes. 1523 76

The p38 mitogen-activated protein kinase (MAPK) pathway is activated by IFNs and other cytokines to mediate signals for important cellular functions, including transcriptional regulation and apoptosis. We examined the role of the p38 pathway in the generation of the effects of myelosuppressive cytokines on human hematopoiesis. Pharmacologic inhibition of p38 using BIX-01208 resulted in reversal of IFN-, tumor necrosis factor-alpha (TNF-alpha)-, and transforming growth factor-beta (TGF-beta)-mediated suppression of human erythroid (blast-forming unit-erythroid) and myeloid (granulocyte-macrophage colony-forming unit) colony formation, consistent with a key role for p38 in the generation of myelosuppressive signals by different cytokines. Similarly, the myelosuppressive effects of TNF-alpha and TGF-beta were reversed by small interfering RNAs targeting p38alpha expression, further establishing the requirement of this kinase in the induction of myelosuppressive responses. As TNF overproduction has been implicated in the pathophysiology of bone marrow failure states, we determined whether pharmacologic inhibition of p38 reverses the hematopoietic defects seen in bone marrows from patients with myelodysplastic syndromes (MDS) and the anemia of chronic disease. Addition of pharmacologic inhibitors of p38 on such bone marrows resulted in increased numbers of erythroid and myeloid progenitors. Similarly, inhibition of the activity of the downstream effectors of p38, MAPK activated protein kinase-2, and mitogen and stress activated kinase 1 partially restored the hematopoietic defect seen in these bone marrows. Taken altogether, our data implicate the p38 MAPK in the pathophysiology of myelodysplasias and suggest that p38 pharmacologic inhibitors may have therapeutic applications in the treatment of MDS.
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PMID:Role of the p38 mitogen-activated protein kinase pathway in cytokine-mediated hematopoietic suppression in myelodysplastic syndromes. 1620 77

Myelodysplastic syndrome (MDS) is a family of clonal disorders characterized by dyshematopoiesis and susceptibility to acute myelogenous leukemia. Tumor necrosis factor-a (TNF-alpha) and transforming growth factor-beta (TGF-beta) are cytokines that play key roles in the pathogenesis of MDS. There have been several reports on the presence of genetic polymorphisms in the DNA sequence encoding the leader sequence of the TGF-beta protein, and in the -308 promoter region of TNF-alpha. The association between TNF-alpha and TGF-beta1 gene polymorphism and the susceptibility to MDS and the progression of the disease was investigated. As compared with healthy control subjects (n = 74), patients with MDS (n = 55) showed no significant deviations in genotype or allele frequencies of TNF-alpha. Similarly, there were no differences in the distribution of TNF-alpha genotypes between the MDS patients with only anemia (mild group) and those with bi- or pancytopenia (severe group). On the other hand the TT homozygosity at codon 10 in exon 1 of TGF-beta1 gene was associated with a severe degree of cytopenia [95% CI OR = 4.889, p = 0.0071]. These findings suggest that the investigated genetic polymorphisms do not predispose to the development of MDS, but that TGF-beta1 gene polymorphism may affect the disease progression.
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PMID:Genetic polymorphisms in patients with myelodysplastic syndrome. 1640 Aug 83

To investigate the regulatory mechanisms of angiogenesis in the development of myelodysplastic syndromes (MDS) and its progression to overt leukaemia (OL), bone marrow samples from control, paired samples from MDS patients before and after transformation to OL (MDS --> OL) and de novo acute myeloid leukaemia (AML) were analysed. Immunohistochemical staining showed a significant increase of bone marrow microvascular density (MVD) in MDS and de novo AML compared with controls. Surprisingly, in MDS, MVD significantly decreased upon transformation to OL, which was also significantly lower than the MVD of de novo AML. This evidence was strengthened by the pattern of angiogenic mediator gene expression, confirming the importance of various angiogenic mediators including vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), tumour necrosis factor alpha (TNFalpha), hepatocyte growth factor (HGF) and the angiopoietin family of mediators (Ang-1 and Ang-2) as well as the receptors for angiogenic mediators, such as VEGF receptor 2 (VEGFR2) and the tyrosine kinase receptor, TIE2. By contrast, the anti-angiogenic mediator, transforming growth factor-beta (TGFbeta) exhibited significantly higher expression in the bone marrow of MDS --> OL, indicating the importance of this cytokine as the suppressive factor of angiogenesis in MDS. These findings indicate that the bone marrow microenvironment in MDS --> OL and de novo AML differs remarkably, suggesting the different efficacy of anti-angiogenic therapy between de novo AML and leukaemia secondary to MDS.
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PMID:Regulation of angiogenesis in the bone marrow of myelodysplastic syndromes transforming to overt leukaemia. 1740 59

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