Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0026986 (myelodysplastic syndrome)
 14,926 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Bone marrow-derived mesenchymal stem cells (MSC) have been defined as primitive, undifferentiated cells, capable of self-renewal and with the ability to give rise to different cell lineages, including adipocytes, osteocytes, fibroblasts, chondrocytes, and myoblasts. MSC are key components of the hematopoietic microenvironment. Several studies, including some from our own group, suggest that important quantitative and functional alterations are present in the stroma of patients with myelodysplasia (MDS). However, in most of such studies the stroma has been analyzed as a complex network of different cell types and molecules, thus it has been difficult to identify and characterize the cell(s) type(s) that is (are) altered in MDS. In the present study, we have focused on the biological characterization of MSC from MDS. As a first approach, we have quantified their numbers in bone marrow, and have worked on their phenotypic (morphology and immunophenotype) and cytogenetic properties. MSC were obtained by a negative selection procedure and cultured in a MSC liquid culture medium. In terms of morphology, as well as the expression of certain cell markers, no differences were observed between MSC from MDS patients and those derived from normal marrow. In both cases, MSC expressed CD29, CD90, CD105 and Prolyl-4-hydroxylase; in contrast, they did not express CD14, CD34, CD68, or alkaline phosphatase. Interestingly, in five out of nine MDS patients, MSC developed in culture showed cytogenetic abnormalities, usually involving the loss of chromosomal material. All those five cases also showed cytogenetic abnormalities in their hematopoietic cells. Interestingly, in some cases there was a complete lack of overlap between the karyotypes of hematopoietic cells and MSC. To the best of our knowledge, the present study is the first in which a pure population of MSC from MDS patients is analyzed in terms of their whole karyotype and demonstrates that in a significant proportion of patients, MSC are cytogenetically abnormal. Although the reason of this is still unclear, such alterations may have an impact on the physiology of these cells. Further studies are needed to assess the functional integrity of MDS-derived MSC.
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PMID:Mesenchymal stem cells in myelodysplastic syndromes: phenotypic and cytogenetic characterization. 1560 71

In order to investigate simultaneously the megakaryocytopoiesis and apoptotic characteristics in bone marrow in patients with myelodysplastic syndromes (MDS), we used CD41 immunoenzyme (alkaline phosphatase anti-alkaline phosphatase) and DNA in situ end-labeling techniques on plastic embedded bone marrow biopsy sections of 29 MDS patients. Fourteen patients with iron deficiency anemia served as controls. The results showed that CD41-positive cells in MDS marrow numbered 26.2 +/- 18.2/mm2 (mean +/- standard deviation) compared with 15.6 +/- 7.1/mm2 in controls (P < 0.05). Numbers of cells with the morphology of micro-megakaryocytes in MDS marrow were significantly higher than in controls (P < 0.01). Furthermore, megakaryocytes in MDS marrow were frequently distributed along trabeculae (in 27 cases) and formed clusters (in 25 cases). Apoptotic megakaryocytes in MDS marrow accounted for just 4.4 and 9.3% of all CD41-positive cells and all apoptotic cells, respectively (P > 0.05 compared with controls), but apoptosis occurred only in micro-megakaryocytes. Based on these observations, we conclude that megakaryocytosis and dysmegakaryocytosis are the features of dyshematopoiesis in MDS marrow. Decreased thrombocyte production and thrombocyte release coming from increased dys(micro)megakaryocytes and abnormally located megakaryocytes perhaps play a more important role in peripheral thrombocytopenia than megakaryocytic apoptosis itself. Apoptosis of micro-megakaryocytes may be a protective biological mechanism to remove useless megakaryocytes.
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PMID:Megakaryocytopoiesis and apoptosis in patients with myelodysplastic syndromes. 1562 28

To verify the expression of type 1 insulin-like growth factor receptor (IGF-IR) and its impact on hematopoietic cells apoptosis in myelodysplastic syndromes (MDS) and acute myeloid leukemias (AML), marrow samples from 16 patients with MDS and 16 patients with AML were examined along with 16 healthy donors as controls. Immunocytochemical methods (alkaline phosphatase anti-alkaline phosphatase) and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (fluorescence) were used simultaneously on nucleated cell cytospins. The ratio of IGF-IR positive cells and apoptotic cells as well as the relationship between them were then analyzed separately. A quantitative real-time reverse transcriptase-polymerase chain reaction (PCR) was administrated for six MDS cases and two normal controls to validate IGF-IR expression detected by immunochemistry. In our assay, IGF-IR appeared to have higher to lower expression rate in turn from AML (86.8+/-13.8%) to MDS (56.8+/-14.3%) and then to normal controls (40.4+/-9.6%) (P<0.01 between each group). In MDS nucleated cells, IGF-IR showed stronger expression in refractory anemia with excess blasts (RAEB)/RAEB in transformation/chronic myelomonocytic leukemia subgroup when compared to RA/RA with ringed sideroblasts cases (64.1+/-3.2 vs 53.5+/-16.2%) (P>0.05). Nucleated cells from MDS marrow underwent more apoptosis (5.4+/-3.0%) than that in normal marrow (1.2+/-0.9%) (P<0.01) and AML marrow (0.3+/-0.4%) (also, P<0.01 between each compared group). For both AML and MDS cases, apoptotic signals presented mainly in individual IGF-IR negative cells (9.0+/-4.8%) and less so in IGF-IR positive cells (1.4+/-2.4%) (P<0.01). When analyzed by groups, cell number with IGF-IR expression showed a negative correlation to apoptotic cells amount (r=-0.852; P<0.01) but positive correlation to their blast count (r=0.677; P<0.01). Outcome from real-time quantitative PCR appeared to have a trend of enhanced IGF-IR expression in advanced MDS subtypes. In conclusion, overexpression of IGF-IR existed in hematopoietic cells in MDS and AML marrows, which appeared to be contributed to disease progress.
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PMID:Expression of type 1 insulin-like growth factor receptor in marrow nucleated cells in malignant hematological disorders: correlation with apoptosis. 1632 78

To determine the expression of Wilms' tumor gene (WT1) in clonal hematopoietic cells in patients with myelodysplastic syndromes (MDS), immunochemistry labelling (alkaline phosphatase anti-alkaline phosphatase) and fluorescence in situ hybridization (FISH) were coperformed on bone marrow cytospins from 18 patients whose abnormal karyotypes had been determined by G-binding analysis. Compared to 12 healthy donors, WT1 positive nucleated cells in MDS marrows were significantly higher (t = 2.30; P = 0.032). Moreover, WT1 was expressed predominantly in MDS clonal cells (with abnormal FISH signals) rather than in non-clonal cells (residual normal cells) (t = 2.19; P = 0.043).
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PMID:Wilms' tumor gene (WT1) is predominantly expressed in clonal hematopoietic cells in myelodysplastic syndromes. 1745 5

A 65-year-old man with myelodysplastic syndrome (MDS) was admitted for progressive jaundice. Diffuse pancreatic swelling and stricture of the main pancreatic duct were observed with elevated serum levels of direct bilirubin, aspartate transaminase, alanine transaminase, alkaline phosphatase, gammaGTP and amylase, and impaired glucose tolerance. Serum IgG and IgG4 levels were highly elevated, and both the direct antiglobulin test and platelet-associated IgG were positive. He was diagnosed with autoimmune pancreatitis associated with MDS, and biliary drainage followed by immunosuppressive therapy ameliorated the jaundice and laboratory findings. In addition to diffuse pancreatic FDG accumulation, fine incorporations of FDG to the lachrymal and submandibular glands were demonstrated, suggesting the recently proposed IgG4+ multiorgan lymphoproliferative syndrome (MOLPS). The etiology of IgG4+ MOLPS is still unknown; however, autoantibodies to blood cells in this case suggested that the autoimmune mechanism, which is caused by abnormal immune functions in MDS patients, might be involved in the pathogenesis of IgG4+ MOLPS.
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PMID:Autoimmune pancreatitis associated with myelodysplastic syndrome. 1975 71

Expression of stem cell phenotype (CD34) and multidrug resistance (MDR) on blast cells of 49 untreated patients with primary myelodysplastic syndromes (MDS) was studied by means of the alkaline phosphatase antialkaline phosphatase technique (APAAP). In 29 patients (59%) CD34 and in 19 patients (39%) MDR positivity was found. Both immunocytological markers showed a strong positive correlation (p<0.0005) and MDR expression was only detectable in CD34 positive cases. When comparing CD34 and MDR expression with well established prognostic parameters, medullary bone marrow (BM) blast percentage was found to be the sole variable which correlated with expression of both cell surface markers. CD34 and MDR negative patients had a better prognosis although only the difference between CD34 positive and CD34 negative cases reached statistical significance. Regarding the prognostic value of immunocytological results and other clinical and hematological parameters medullary blast cell infiltration remained the strongest predictive variable for survival and AML transformation. In 6 patients sequential immunocytological analysis during progression of disease were performed. In contrast to stable CD34 expression a marked increase in MDR expression after AML development could be noted in 2 cases.
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PMID:Expression of cd34 and p-glycoprotein - prognostic-significance in primary myelodysplastic syndromes. 2155 21

Three patients with myelodysplastic syndrome (MDS) had absent or extremely low levels of neutrophil alkaline phosphatase (NAP) activity (arbitrarily defined as an NAP score <10). All patients showed varying degrees of hypogranulation in neutrophil morphology. The NAP activity levels transiently normalized following the administration of granulocyte colony-stimulating factor (G-CSF) in two cases. No patients experienced any severe infectious episodes. These results suggest that NAP activity is not central to the neutrophil function.
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PMID:Absent or extremely low neutrophil alkaline phosphatase activity levels in patients with myelodysplastic syndromes. 2341 5

The pathogenesis of myelodysplastic syndromes (MDS) has not been completely understood, and insufficiency of the hematopoietic microenvironment can be an important factor. Mesenchymal stem cells (MSCs) and osteoblasts are key components of the hematopoietic microenvironment. Here, we measured the expression of multiple osteogenic genes in 58 MSCs from MDS patients with different disease stages and subtypes by real-time PCR and compared the osteogenic differentiation of MSCs from 20 MDS patients with those of MSCs from eight normal controls quantitatively and dynamically. The mRNA level of Osterix and RUNX2, two key factors involved in the early differentiation process toward osteoblasts, was significantly reduced in undifferentiated MSCs from lower-risk MDS. After osteogenic induction, lower-risk MDS showed lower alkaline phosphatase activity, less intense alizarin red S staining, and lower gene expression of osteogenic differentiation markers; however, higher-risk MDS was normal. Finally, in bone marrow biopsy, the number of osteoblasts was significantly decreased in lower-risk MDS. These results indicate that MSCs from lower-risk MDS have impaired osteogenic differentiation functions, suggesting their insufficient stromal support in MDS.
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PMID:Impaired osteogenic differentiation of mesenchymal stem cells derived from bone marrow of patients with lower-risk myelodysplastic syndromes. 2444 67

TET2 is a methylcytosine dioxygenase that is frequently mutated in myeloid malignancies, notably myelodysplasia and acute myeloid leukemia. TET2 catalyses the conversion of 5'-methylcytosine to 5'-hydroxymethylcytosine within DNA and has been implicated in the process of genomic demethylation. However, the mechanism by which TET2 loss of function results in hematopoietic dysplasia and leukemogenesis is poorly understood. Here, we show that TET2 is expressed in undifferentiated embryonic stem cells and that its knockdown results in reduction of 5'-hydroxymethylcytosine in genomic DNA. We also present DNA methylation data from bone marrow samples obtained from patients with TET2-mutated myelodysplasia. Based on these findings, we sought to identify the role of TET2 in regulating pluripotency and differentiation. We show that overexpression of TET2 in a stably integrated transgene leads to increased alkaline phosphatase expression in differentiating ES cells and impaired differentiation in methylcellulose culture. We speculate that this effect is due to TET2-mediated expression of stem cell genes in ES cells via hydroxylation of 5'-methylcytosines at key promoter sequences within genomic DNA. This leads to relative hypomethylation of gene promoters as 5'-hydroxymethylcytosine is not a substrate for DNMT1-mediated maintenance methylation. We sought to test this hypothesis by cotransfecting the TET2 gene with methylated reporter genes. The results of these experiments are presented.
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PMID:TET2 Inhibits Differentiation of Embryonic Stem Cells but Does Not Overcome Methylation-Induced Gene Silencing. 2527 35

Eight patients with myelodysplastic syndrome (MDS) and chromosome abnormalities were studied by a combined method which allows simultaneous analysis of the karyotype and immunophenotype of the same mitotic cell. To determine the cell lineages with abnormal karyotype, monoclonal antibodies in the alkaline phosphatase-antialkaline phosphatase (APAAP) staining methods were used All patients with MDS showed metaphases with abnormal karyotype in cells belonging to granulocytic/monocytic lineage. In 7 patients studied the leukaemic process also involved erythrocytic and/or megakaryocytic lineages. In 4 patients with 5q- chromosome it was evident that at least the granulocytic/monocytic and erythrocytic cell lineages participated in the clonal proliferation. One patient with 5q- chromosome at initial diagnosis showed a shift from megakaryocytic to a granulocytic/monocytic cell population at the time of acute leukaemia These findings indicate multi-lineage involvement in patients with MDS who have karyo-typic abnormalities.
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PMID:Immunophenotype of Abnormal Metaphases Demonstrating Multilineage Involvement in Myelodysplastic Syndromes. 2745 35


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