Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0039730 (thalassemia)
 10,305 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In vivo gene transfer is being considered in the systemic delivery of therapeutic proteins. This report evaluates the use of AAV vectors administered into muscle to deliver erythropoietin (Epo) for the treatment of anemia in a mouse model of beta-thalassemia. Injection of vector expressing Epo from a constitutive promoter resulted in Epo overproduction and improved erythropoiesis. However, severe and lethal polycythemia developed. In order to titrate the expression of Epo to therapeutic and non-toxic levels, vectors were constructed to allow pharmacologic control of Epo transcription. Specifically, expression of Epo was dependent on the presence of a chimeric transcription factor that is activated by the orally available small molecule drug rapamycin. beta-thalassemic mice injected with vectors containing the regulated Epo gene failed to show any effect until they were administered a regimen of rapamycin, which led to the production of Epo and an increase in hematocrit values. Epo expression and its hematologic consequences were directly dependent on the dose of rapamycin and were completely reversed when rapamycin was withdrawn. The increase in hematocrit was associated with partial improvements in the abnormalities of red blood cell morphology. This study confirms the value of pharmacologic regulation of transgene expression in the development of safe and effective gene therapies in which biologically active secreted proteins are produced.
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PMID:Regulated expression of erythropoietin from an AAV vector safely improves the anemia of beta-thalassemia in a mouse model. 1272 12

We report in this paper that the DNA-binding drug mithramycin is a potent inducer of gamma-globin mRNA accumulation and fetal hemoglobin (HbF) production in erythroid cells from healthy human subjects and beta-thalassemia patients. Erythroid precursors derived from peripheral blood were grown in 2-phase liquid culture. In this procedure, early erythroid progenitors proliferate and differentiate during phase 1 (in the absence of erythropoietin) into late progenitors. In phase 2, in the presence of erythropoietin, the latter cells continue their proliferation and mature into Hb-containing orthochromatic normoblasts. Compounds were added on days 4 to 5 of phase 2 (when cells started to synthesize Hb), and cells were harvested on day 12. Accumulation of mRNAs for gamma-globin, beta-globin, alpha-globin, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and beta-actin were measured by real-time quantitative reverse transcription-polymerase chain reaction (RT-PCR); induction of HbF was analyzed by high-performance liquid chromatography (HPLC) and, at cellular level, by flow cytometry. We demonstrated that mithramycin was able to up-regulate preferentially gamma-globin mRNA production and to increase HbF accumulation, the percentage of HbF-containing cells, and their HbF content. Mithramycin was more effective than hydroxyurea, being, in addition, not cytotoxic. This was shown by the lack of cytotoxicity on erythroid and myeloid in vitro primary cell cultures treated with mithramycin at concentrations effective for HbF induction. These results are of potential clinical significance because an increase of HbF alleviates the symptoms underlying beta-thalassemia and sickle cell anemia. The results of this report suggest that mithramycin and its analogs warrant further evaluation as potential therapeutic drugs.
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PMID:Mithramycin induces fetal hemoglobin production in normal and thalassemic human erythroid precursor cells. 1273 78

Human umbilical cord blood (CB) has moved from the status of biological waste to that of a valuable source of haematopoietic stem (HS) cells. There are potentially three major clinical applications for HS cells and ex vivo-expanded HS cells: reconstitution of haematopoiesis in patients undergoing chemotherapy; gene therapy (e.g. in thalassaemia, sickle cell anaemia); and large-scale production of mature blood cells. Erythropoiesis is accomplished by highly complex interactions of haematopoietic progenitor cells, stromal cells and cytokines in the bone marrow. Among them, erythropoietin is the principal regulator. Ex vivo cell culture experiments to obtain mature red blood cells were the focus of this study. Attempts to elucidate appropriate medium components and amounts of haematopoietic growth factors were successful: enucleated and haemoglobin-filled erythroid cells were obtained from primitive HS cells. Dimethylsulphoxide (DMSO) was found to be of particular importance as an efficient differentiation inducer. The differentiation process was followed microscopically and by fluorescence-activated cell sorting (FACS). Using the micropipette aspiration technique, the elastic properties of erythroid cells were evaluated as erythropoiesis progressed. Discocyte-like cells, comprising reticulocytes and finally differentiated red blood cells, showed an about ten-fold higher membrane shear modulus compared with control cells.
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PMID:Biological and mechanical quality of red blood cells cultured from human umbilical cord blood stem cells. 1280 2

Nine patients with either beta-thalassaemia/haemoglobin E (7) or homozygous beta-thalassaemia (2) not requiring regular transfusions were treated with the oral iron chelator, deferiprone 25-50 mg/kg/d for between 17 and 86 weeks (mean 49 weeks). There were significant decreases in serum ferritin (initial mean +/- standard deviation 2168 +/- 1142, final 418 +/- 247 micro g/l; t-test for paired samples, P = 0.005), hepatic iron (initial 20.3 +/- 6.26, final 11.7 +/- 4.83 mg/g/dry weight; P = < 0.02), red cell membrane iron (initial 76.2 +/- 3.64, final 7.2 +/- 0.56 mmol/mg protein; P = < 0.0005) and serum non-transferrin bound iron (initial 9.0 +/- 0.56, final 5.9 +/- 0.89 micro mol/l; P = < 0.0005). There was also a significant rise in serum erythropoietin (initial 240 +/- 195.1, final 433.2 +/- 269.2 U/l; P = 0.034). The haemoglobin level rose in three patients and transfusion requirements were reduced substantially in four patients. Serum thiobarbituric acid reactive substance (TBARS) also fell in six of eight patients. Patients generally improved clinically, with weight gain observed. Side-effects were mild and included gastrointestinal symptoms (6) and arthralgia (1), not requiring withdrawal of the drug. One patient died at 17 weeks of therapy as a result of an intercurrent infection. His neutrophil count was normal. We conclude that deferiprone is an effective, well-tolerated iron chelator for patients with thalassaemia intermedia. Further studies are needed to determine the optimum dose and length of treatment needed to reduce iron burden to a safe level in these patients.
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PMID:Clinical trial of deferiprone iron chelation therapy in beta-thalassaemia/haemoglobin E patients in Thailand. 1284 1

We evaluated sera from 58 thalassemic patients for the presence of antierythropoietin antibodies to investigate whether these autoantibodies may relate with modest response to treatment with recombinant human erythropoietin (rhEpo). Thirty-seven patients had beta-thalassemia major, 9 patients had beta-thalassemia intermedia, and 12 patients had sickle/beta(+)-thalassemia. Of 58 patients, 24 were on rhEpo treatment in order to increase the intervals between transfusions or the hemoglobin (Hb) values. The study population was divided into three groups according to rhEpo treatment. Group A consisted of 15 patients who were on rhEpo treatment (400-600 IU/kg three times per week, subcutaneously) showing an increase of Hb values or reduction of transfusion requirements. Group B included 9 patients who did not respond to rhEpo and group C consisted of 34 patients who did not receive rhEpo. Laboratory studies included a complete blood count, measurement of serum erythropoietin, immunological evaluation, and determination of antierythropoietin antibodies using enzyme-linked immunosorbent assay (ELISA). There were no significant differences among groups A, B, and C concerning age, Hb, and endogenous erythropoietin values. Fifteen patients had positive antinuclear antibodies and three patients had positive rheumatoid factor. Antierythropoietin antibodies were detected in the sera of seven patients (five men and two women) who received rhEpo. The male patients and one female patient had no response to rhEpo while the other female patient showed response when the dose increased. Other autoantibodies seem to have no clinical significance. In the present study, we detected for the first time in thalassemia patients the presence of antierythropoietin antibodies, which may contribute to rhEpo resistance. Thalassemia patients with low response rates to rhEpo should be evaluated for the presence of antierythropoietin antibodies.
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PMID:Antierythropoietin antibodies in thalassemia patients. 1453 Aug 77

In dialysis patients beta-thalassemia is a cause of resistance to erythropoietin (EPO). The aim of the present study is to evaluate the relationship between the amount of circulating anomalous hemoglobin chain and EPO resistance in hemodialysis. Ten hemodialyzed patients with beta-thalassemia minor were studied. The mean hemoglobin level was 9.22 +/- 0.91 g/dl, the HbA2 ranging between 5.6 and 6.8%; the weekly EPO dose was 13,500 +/- 7,185 IU/week and significantly correlated with HbA2 (r = 0.965; p = 0.0001). When stratifying patients in two groups according to HbA2 level (LOW <6%, n = 4; HIGH >6%, n = 6; HbA2 levels, respectively, 5.7 +/- 0.1 and 6.4 +/- 0.3 g/dl, p = 0.002), it was evidenced that the need of EPO was 13,200 +/- 3,033 IU/week in LOW and 36,167 +/- 13,060 IU/week in HIGH (p < 0.001). The EPO Resistance Index in the two groups was 13.4 +/- 4.1 IU/kg BW/week/g Hb in LOW and 21.9 +/- 10.0 in HIGH (p < 0.05). No differences were evidenced between the two groups regarding age, dialysis, body weight, serum levels of urea nitrogen, creatinine, albumin, C-reactive protein, aluminum, ferritin, transferrin and parathyroid hormone. In conclusion, in patients with beta-thalassemia minor on chronic hemodialysis, the amount of anomalous hemoglobin chain directly correlate with EPO dose, strongly indicating the magnitude of resistance to erythropoietin.
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PMID:Relationship between resistance to erythropoietin and high anomalous hemoglobin levels in hemodialysis patients with beta-thalassemia minor. 1458 79

Adeno-associated viral (AAV) vectors are derived from a nonpathogenic, replication-deficient virus with a small (~4.7-kb) single-stranded DNA genome. AAV vectors are devoid of viral-coding sequences and may efficiently transfer genes to nondividing cells such as muscle fibers or hepatocytes following in vivo transduction. Recombinant AAV can be administered to skeletal muscle of experimental animals and, as recently documented in a Phase I clinical trial, to humans at high vector doses without local or systemic toxicity (8,9). The potential of the vector to activate cytotoxic T lymphocytes is greatly reduced compared with some other viral vectors, thereby reducing the risk of inflammation at the site of gene transfer (7,10,11). Sustained expression of therapeutic transgenes such as coagulation factor IX (F.IX), erythropoietin, leptin, insulin-like growth factor (IGF), sarcoglycans, mini-dystrophin genes, alpha1-antitrypsin, and others have been demonstrated (2,12-18). Efficient gene transfer to myofibers by intramuscular (im) injection has been shown in several species including mice, hamsters, dogs, and nonhuman primates (6-8,13,19). These studies resulted in various levels of correction of the disease phenoypes in small and large animal models of hemophilia B (F.IX deficiency), muscular dystrophy, obesity, age-related atrophy, and beta-thalassemia (8,12,13,15,17,18,20-25).
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PMID:AAV-mediated gene transfer to skeletal muscle. 1497 May 92

The coinheritance of beta-thalassemia major with the genotype of Hb H disease is extremely rare, with few reported cases. We investigated the hematological, biochemical, biosynthetic, molecular and pathophysiological parameters to evaluate a rare male patient with this compound syndrome. The patient was studied at first diagnosis during hospitalization at 50 years of age and subsequently followed up for more than a year. Examinations included full hematological, biochemical, biosynthetic, molecular, pathophysiological and clinical parameters. Besides standard parameters, we additionally measured reticulocyte hemoglobin content (CHr), erythropoietin (Epo), soluble transferrin receptors (sTfR), oxygen pressure at 50% hemoglobin saturation (P50), 2,3-bisphosphoglycerate (2,3-BPG), total glutathione (GSHt), oxidized glutathione (GSSG), malonyldialdehyde (MDA), nontransferrin-bound iron (NTBI), vitamins A and E. The male patient was first hospitalized for a 2-day period at 50 years of age, following the finding of marked anemia (hematocrit 20%) during a blood test to investigate the cause of fatigue in the absence of weight-loss or other notable symptomatology. He had never been transfused, maintaining Hb 85-95 g/l. Definitive diagnosis was achieved through DNA studies, which showed coexistence of beta-thalassemia major (IVSI-6 T > C/IVSI-I G > A) with Hb H disease (-alpha(3.7)/-(Med)). Alpha/non-alpha globin chain biosynthesis was completely balanced. Parameters demonstrated a well-compensated anemia with ineffective erythropoiesis and oxidative stress, which was ameliorated following splenectomy. In conclusion, this case is a remarkable example that the coinheritance of severe forms of beta-thalassemia and alpha-thalassemia interact in a "synergistic" manner to almost complete balance the symptoms of classic thalassemia syndromes.
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PMID:A rare example that coinheritance of a severe form of beta-thalassemia and alpha-thalassemia interact in a "synergistic" manner to balance the phenotype of classic thalassemic syndromes. 1500 25

The most common single genetic disorder and a major public health issue in Greece and other Mediterranean countries is beta-thalassemia. Current therapeutic approaches for homozygous beta-thalassemia entail blood transfusions and iron chelation therapy with deferoxamine or deferiprone for preventing tissue hemosiderosis. Recently, much effort has focused on various inducers of fetal hemoglobin (HbF) such as recombinant human erythropoietin (rHuEPO), especially in beta-thalassemia intermedia. Ten adult patients, 5 with beta-thalassemia major and 5 with beta-thalassemia intermedia, received 150 IU/kg rHuEPO (epoetin-alpha) subcutaneously three times a week. Seven patients were transfused every 14-30 days and 3 with beta-thalassemia intermedia were only occasionally transfused. The minimum duration of treatment was 12 weeks in order to define if there was any response. Transfusion intervals were modified according to the rHuEPO response to maintain stable Hb values. Lower transfusion requirements were observed in 5 patients after rHuEPO treatment (p = 0.028). In the 3 non-transfused patients, Hb values increased, and the patients are still being treated and followed up for a period ranging from 14 weeks to 2 years. Two patients with thalassemia major discontinued treatment after 12 weeks, as they did not achieve any response regarding transfusion requirements or Hb values. Pretreatment serum transferrin receptor levels were higher than in controls (p < 0.001) and significantly increased following rHuEPO treatment (p = 0.027). Patients had higher serum endothelin-3, sICAM-1 and sE-selectin values before rHuEPO treatment compared to controls (p < 0.001, p < 0.001 and p = 0.016, respectively), but these values were not altered during treatment. HbF values presented a slight, non-significant increase. rHuEPO treatment has a beneficial effect in transfusion-dependent beta-thalassemia patients. Although a slight increase in HbF levels was observed, other possible mechanisms are probably involved. None of our patients experienced thrombotic complications and a rise in blood pressure.
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PMID:Treatment of beta-thalassemia patients with recombinant human erythropoietin: effect on transfusion requirements and soluble adhesion molecules. 1515 10

Iron deficiency anaemia and the thalassemia syndromes, a group of disorders resulting from inherited abnormality of globin chain production, are common causes of anaemia in Thailand, and in the Far East in general. Monitoring erythropoiesis in these patient is very important in evaluating the disease and the response to treatment. Recently, our group has just reported the feasibility in using serum erythropoietin (EPO) for monitoring purposes in thalassemia and demonstrated that the determination of serum EPO can be an alternative choice in the follow up of these conditions. This study reports a cost effectiveness analysis comparing the recently reported radioimmunoassay (RIA) for serum EPO determination and the previously used tool, the reticulocyte count. The study reports a higher detection rate for ineffective erythropoiesis when using serum EPO determination, however, the increased sensitivity is at balanced by a higher unit cost. In this analysis, the cost effectiveness for serum EPO and reticulocyte are 208.33 and 50 baht/detection, respectively. () Therefore, the reticulocyte count is more cost effective and is recommended for routine usage in our current medico-economic setting.
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PMID:Comparison of cost effectiveness between measuring the serum erythropoietin level and reticulocyte count for monitoring thalassemic patients: a note in Thai beta thalassemia/Hb E subjects. 1562 41


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