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Recent research highlights the significant impact of the gut microbiota on health and disease. Thalassemia, a hereditary blood disorder, requires regular blood transfusions, leading to an accumulation of iron in the body. Such changes could potentially alter the intestinal microbiota, thereby increasing the susceptibility of thalassemic patients to infection. In this study, we analyzed the fecal microbiota of 70 non-transfusion-dependent (NTDT) β-thalassemia/HbE patients and 30 healthy controls. Our findings indicate that iron chelation intervention had no detectable effect on the microbiome profile of thalassemic patients. However, the cross-sectional analysis revealed that the bacterial diversity and community structure in patients were significantly less diverse and distinct compared to those of healthy subjects. Using reference frames, we were also able to demonstrate that bacterial taxa that are known to produce short chain fatty acids, from the genera Alistipes, Coprococcus, and Oscillospira, and those from the family Ruminococcaceae, were less prevalent in the patients. In contrast, bacterial taxa associated with an unhealthy gut, including the genus Clostridium and those from the families Fusobacteriaceae, Enterobacteriaceae, and Peptostrptococcaceae, were more prevalent in patients and found to be correlated with higher levels of ferritin. Collectively, these changes in the microbiota could be regarded as markers of raised ferritin levels, and therefore, awareness should be exercised as they could interfere, albeit indirectly, with the treatment of the co-morbidities of thalassemia. [ABSTRACT FROM AUTHOR]

Neutrophil dysfunction contributes to a high susceptibility to severe bacterial infection which is a leading cause of morbidity and mortality in β-thalassaemia/HbE, especially in splenectomised patients. This study demonstrated another abnormality of neutrophil function, namely neutrophil extracellular trap (NET) formation in splenectomised and non-splenectomised β-thalassaemia/HbE patients who had iron overload. A classification system of morphological NET formation using confocal microscopy was developed, and samples were categorized into early and late phases which were subdivided into web-like and non-web structures. At baseline, neutrophils from non-splenectomised patients (58 ± 4%) and splenectomised patients (65 ± 3%) had higher early phase NETs than those from normal subjects (33 ± 1%). As a mimic of iron overload and infection, haemin/PMA/LPS treatment led to a significant reduction of early NETs and an increase of late NETs in neutrophils from normal and non-splenectomised patients. Interestingly, neutrophils from splenectomised patients had impaired development of late NETs. This suggests that during infection bacteria might not be trapped and may spread from the site of infection resulting in higher susceptibility to severe bacterial infection in splenectomised patients. [ABSTRACT FROM AUTHOR]

β-Thalassemia/HbE disease has a wide spectrum of clinical phenotypes ranging from asymptomatic to dependent on regular blood transfusions. Ability to predict disease severity is helpful for clinical management and treatment decision making. A thalassemia severity score has been developed from Mediterranean β-thalassemia patients. However, different ethnic groups may have different allele frequency and linkage disequilibrium structures. Here, Thai β0-thalassemia/HbE disease genome-wild association studies (GWAS) data of 487 patients were analyzed by SNP interaction prioritization algorithm, interacting Loci (iLoci), to find predictive SNPs for disease severity. Three SNPs from two SNP interaction pairs associated with disease severity were identifies. The three-SNP disease severity risk score composed of rs766432 in BCL11A, rs9399137 in HBS1L-MYB and rs72872548 in HBE1 showed more than 85% specificity and 75% accuracy. The three-SNP predictive score was then validated in two independent cohorts of Thai and Malaysian β0-thalassemia/HbE patients with comparable specificity and accuracy. The SNP risk score could be used for prediction of clinical severity for Southeast Asia β0-thalassemia/HbE population. [ABSTRACT FROM AUTHOR]

Increased expression of fetal hemoglobin (HbF) improves the clinical severity of β-thalassemia patients. EHMT1/2 histone methyltransferases are epigenetic modifying enzymes that are responsible for catalyzing addition of the repressive histone mark H3K9me2 at silenced genes, including the γ-globin genes. UNC0638, a chemical inhibitor of EHMT1/2, has been shown to induce HbF expression in human erythroid progenitor cell cultures. Here, we report the HbF-inducing activity of UNC0638 in erythroid progenitor cells from β-thalassemia/HbE patients. UNC0638 treatment led to significant increases in γ-globin mRNA, HbF expression, and HbF-containing cells in the absence of significant cytotoxicity. Moreover, UNC0638 showed additive effects on HbF induction in combination with the immunomodulatory drug pomalidomide and the DNMT1 inhibitor decitabine. These studies provide a scientific proof of concept that a small molecule targeting EHMT1/2 epigenetic enzymes, used alone or in combination with pomalidomide or decitabine, is a potential therapeutic approach for HbF induction. Further development of structural analogs of UNC0638 with similar biological effects but improved pharmacokinetic properties may lead to promising therapies and possible clinical application for the treatment of β-thalassemia. [ABSTRACT FROM AUTHOR]

A simple probe pair was designed for the detection of hemoglobin E (HbE) genotype, a single-point mutation that leads to abnormal red blood cells commonly found in South East Asia. The key to differentiation is the use of a conformationally constrained peptide nucleic acid (PNA) that was immobilized on carboxymethylcellulose-modified paper. This was then used for target DNA binding and visualization by an enzyme-catalyzed pigmentation. The biotinylated target DNA bound to the immobilized probe was visually detected via alkaline phosphatase-linked streptavidin. This enzyme conjugate catalyzed the dephosphorylation of the substrate 5-bromo-4-chloro-3-indolyl phosphate, leading to a series of reactions that generate an intense, dark blue pigment. The test was validated with 100 DNA samples, which shows good discrimination among different genotypes (normal, HbE, and heterozygous) with 100% accuracy when optimal conditions of analysis were applied. The method does not require temperature control and can be performed at ambient temperature. This is an attractive feature for diagnosis in primary care, which accounts for a large part of affected population. [ABSTRACT FROM AUTHOR]

Thalassemia has a high prevalence in Thailand. Oxidative damage to erythroid cells is known to be one of the major etiologies in thalassemia pathophysiology. Oxidative stress status of thalassemia is potentiated by the heme, nonheme iron, and free iron resulting from imbalanced globin synthesis. In addition, levels of antioxidant proteins are reduced in α-thalassemia and β-thalassemia erythrocytes. However, the primary molecular mechanism for this phenotype remains unknown. Our study showed a high expression of miR-144 in β- and α-thalassemia. An increased miR-144 expression leads to decreased expression of nuclear factor erythroid 2-related factor 2 (NRF2) target, especially in α-thalassemia. In α-thalassemia, miR-144 and NRF2 target are associated with glutathione level and anemia severity. To study the effect of miR-144 expression, the gain-loss of miR-144 expression was performed by miR inhibitor and mimic transfection in the erythroblastic cell line. This study reveals that miR-144 expression was upregulated, whereas NRF2 expression and glutathione levels were decreased in comparison with the untreated condition after miR mimic transfection, while the reduction of miR-144 expression contributed to the increased NRF2 expression and glutathione level compared with the untreated condition after miR inhibitor transfection. Moreover, miR-144 overexpression leads to significantly increased sensitivity to oxidative stress at indicated concentrations of hydrogen peroxide (H2O2) and rescued by miR-144 inhibitor. Taken together, our findings suggest that dysregulation of miR-144 may play a role in the reduced ability of erythrocyte to deal with oxidative stress and increased RBC hemolysis susceptibility especially in thalassemia. [ABSTRACT FROM AUTHOR]

Heterogeneity of HbF levels in β0-thalassemia/HbE disease has been reported to be associated with variations in clinical manifestations of the disease, and several genetic-modifying factors beyond the β-globin gene cluster have been identified as HbF regulators. Down-regulation or heterozygous mutations of Krüppel-like factor 1 (KLF1) is associated with elevated HbF levels in non-thalassemia subjects. This study confirms that experimental down-regulation of KLF1 in β0-thalassemia/HbE-derived erythroblasts significantly increases HbF production (up to 52.3 ± 2.4%), albeit with slightly delayed erythroid terminal differentiation. KLF1 exome sequencing of 130 Thai β0-thalassemia/HbE patients without co-inheritance of α-thalassemia found six patients with KLF1 heterozygous mutations including rs2072596 (p.F182L; n = 5) and rs745347362 (p.P284L; n = 1) missense mutations. However, while these patients had high HbF levels (38.1 ± 7.5%), they were all associated with a severe clinical phenotype. These results suggest that while reduction of KLF1 expression in β0-thalassemia/HbE erythroblasts can increase HbF levels, it is not sufficient to alleviate the clinical phenotype. [ABSTRACT FROM AUTHOR]

Abnormal red blood cell (RBC) clearance in β-thalassemia is triggered by activated monocytes. Recent reports indicate that miRNA (miR-) plays a role in monocyte activation. To study phagocytic function, we co-cultured monocytes of normal, non-splenectomized and splenectomized β-thalassemia/HbE individuals with RBCs obtained from normal, non-splenectomized and splenectomized β-thalassemia/HbE individuals. The phagocytic activity of β-thalassemia/HbE monocytes co-cultured with β-thalassemia/HbE RBCs was significantly higher than that of normal monocytes co-cultured with normal RBCs. Upregulation of monocyte miR-155 was observed in β-thalassemia/HbE patients. Increased miR-155 was associated with reductions in BTB and CNC Homology1 (BACH1) target gene expression and increased phagocytic activity of β-thalassemia/HbE monocytes. Taken together, these findings suggested that increased miR-155 expression in activated monocytes leads to enhanced phagocytic activity via BACH-1 regulation in β-thalassemia/HbE. This provides novel insights into the phagocytic clearance of abnormal RBCs in β-thalassemia/HbE. [ABSTRACT FROM AUTHOR]

Atonal homolog 8 (ATOH8) is defined as a positive regulator of hepcidin transcription, which links erythropoietic activity with iron-sensing molecules. In the present study, we investigated the association between hepcidin and ATOH8 expression in β-thalassemia. We found that inhibition of hepcidin expression in β-thalassemia is correlated with reduced ATOH8 expression. Hepatic hepcidin 1 (Hamp1) and Atoh8 mRNA expression were down-regulated in β-thalassemic mice. Hepcidin (HAMP) and ATOH8 mRNA expression were consistently suppressed in Huh7 cells cultured in medium supplemented with β-thalassemia patient serum. The Huh7 cells, which were transfected with ATOH8-FLAG expression plasmid and cultured in the supplemented medium, exhibited increased levels of ATOH8 mRNA, ATOH8-FLAG protein, pSMAD1,5,8, and HAMP mRNA. Interestingly, over-expression of ATOH8 reversed the effects of hepcidin suppression induced by the β-thalassemia patient sera. In conclusion, hepcidin suppression in β-thalassemia is associated with the down-regulation of ATOH8 in response to anemia. We, therefore, suggest that ATOH8 is an important transcriptional regulator of hepcidin in β-thalassemia. [ABSTRACT FROM AUTHOR]

Thromboembolic events including cerebral thrombosis, deep vein thrombosis, and pulmonary embolism are major complications in β-thalassemia. Damaged red blood cells and chronic platelet activation in splenectomized β-thalassemia/HbE patients were associated with increased microparticles (MPs) releases into blood circulation. MPs are small membrane vesicles, which play important roles on coagulation. However, the role of MP in thalassemia is poorly understood. In this study, the effects of splenectomized-MPs on platelet activation and aggregation were investigated. The results showed that isolated MPs from fresh platelet-free plasma of patients and normal subjects directly induce platelet activation, platelet aggregation, and platelet-neutrophil aggregation in a dose-dependent manner. Interestingly, MPs obtained from splenectomized patients are more efficient in induction of platelet activation (P-selectin+) when compared to MPs from normal subjects (P < 0.05), tenfold lower than pathophysiological level, at 1:0.1 platelet MP ratio. Co-incubation of splenectomized-MPs with either normal-, non-splenectomized- or splenectomized-platelets at 1:10 platelet MP ratio increased platelet activation up to 5.1 ± 2.2, 5.6 ± 3.7, and 9.5 ± 3.0%, respectively, when normalized with individual baseline. These findings suggest that splenectomized patients were proned to be activated by MPs, and splenectomized-MPs could play an important role on chronic platelet activation and aggregation, leading to thrombus formation in β-thalassemia/HbE patients. [ABSTRACT FROM AUTHOR]

Ineffective erythropoiesis in β-thalassemia patients is caused by the premature death of red blood cell precursors due to excess α-globin chains. As a consequence, patients develop chronic anemia and hypoxia. Upregulation of miR-210, a hypoxia-induced miRNA, has been shown to regulate globin gene expression and erythroid differentiation in β-thalassemia/HbE erythroid progenitor cell culture. The present study examined whether the expression of miR-210 in circulation reflects the anemic condition in these patients. The level of miR-210 expression was directly examined from red blood cells and plasma of β-thalassemia/HbE patients. Transferrin receptor, a marker of erythropoiesis activity, was also analyzed. Increased expression of both red blood cells and plasma miR-210 as well as elevated levels of serum transferrin receptor in β-thalassemia/HbE patients were observed when compared to those of normal individuals (p < 0.05). In addition, red blood cell miR-210 level was inversely correlated with hemoglobin levels (r = -0.7054, p < 0.01) and hematocrit (r = -0.6017, p < 0.05). The higher expression of miR-210 in these patients may be the consequence of hypoxia occurring from the lower hemoglobin level. Thus, analysis of red blood cell miR-210 may be useful as a method for assessing hypoxia in β-thalassemia patients. [ABSTRACT FROM AUTHOR]

During erythropoiesis, iron levels need to be carefully regulated to ensure there is sufficient iron available for hemoglobin synthesis, but that there is no excess to cause damage to the developing erythroblast. Iron influx to the developing erythroblast is controlled by the expression of the transferrin receptor, while iron efflux is regulated by ferroportin (FPN), the sole iron-exporting protein. FPN is encoded through multiple messenger RNAs (mRNAs) some of which contain an iron-responsive element (variant I mRNAs) and some of which do not (variant II mRNAs). This study sought to investigate the expression of the FPN mRNAs in developing erythroblasts from normal controls and β(0)-thalassemia/Hb E patients. While levels of FPN protein were relatively constant, marked reductions of the variant I message were seen in erythroblasts from β(0)-thalassemia/Hb E patients as compared to normal control cells, particularly in late erythropoiesis. Variant II mRNAs were generally increased during erythroid differentiation. No difference was seen in levels of either transferrin or ferritin heavy chain expression. While no difference was observed in labile iron pools under normal culture conditions, erythroblasts from β(0)-thalassemia/Hb E patients showed a significantly reduced expression of total FPN message under high iron conditions as compared to normal control erythroblasts. These results are consisted with dysregulation of iron efflux from the maturing erythroblast in β(0)-thalassemia/Hb E patients, and this dysregulation possibly contributes to ineffective erythropoiesis seen in these patients. [ABSTRACT FROM AUTHOR]

Thalassemia is an inherited disorder of hemoglobin molecules that is characterized by an imbalance of α- and β-globin chain synthesis. Accumulation of unbound α-globin chains in erythroid cells is the major cause of pathology in β-thalassemia. Stimulation of γ-globin production can ameliorate disease severity as it combines with the α-globin to form fetal hemoglobin. We examined γ-globin-inducing effect of curcuminoids extracted from Curcuma longa L. and their metabolite reduced forms in erythroid leukemia K562 and human primary erythroid precursor cells. The results showed that curcuminoid compounds, especially bisdemethoxycurcumin are potential γ-globin enhancers. We also demonstrated that its reduced analog, hexahydrobisdemethoxycurcumin (HHBDMC), is most effective and leads to induction of γ-globin mRNA and HbF in primary erythroid precursor cells for 3.6 ± 0.4- and 2.0 ± 0.4-folds, respectively. This suggested that HHBDMC is the potential agent to be developed as a new therapeutic drug for β-thalassemia and related β-hemoglobinopathies. [ABSTRACT FROM AUTHOR]

The severity of thalassemia is currently classified based on clinical manifestations and multiple tests. In the present study, we performed a plasma proteome analysis to identify differentially expressed proteins compared between normal subjects and patients with mild and severe forms of β-thalassemia/hemoglobin E (Hb E). Plasma samples were collected from patients with mild ( n = 8) and severe ( n = 12) forms as well as healthy normal individuals ( n = 12). Clinical chemistry revealed that several parameters, i.e., hematological indices, oxidative stress markers, antioxidant enzymes, and erythropoietic activity, had significant differences among these three groups. After removal of seven major abundant proteins, the plasma proteome profiles were compared using two-dimensional gel electrophoresis. Spot matching, quantitative intensity analysis, and statistics revealed differential levels of 32 and 9 proteins when comparing normal vs. patients and mild vs. severe forms, respectively. These proteins were successfully identified by quadrupole time-of-flight mass spectrometry and/or tandem mass spectrometry. The decreased level of ADP-ribosylation factor guanine nucleotide-exchange factor 2 in β-thalassemia/Hb E patients compared to healthy individuals and the decreased level of endothelin-converting enzyme 2 in severe form compared to the mild form of the disease were validated by Western blot analysis. Our data provide a number of proteins that may lead to better understanding of the pathophysiology of thalassemia or for novel biomarkers which can be used to simply differentiate mild and severe forms of β-thalassemia/Hb E without any need for multiple tests. [ABSTRACT FROM AUTHOR]

Iron-overload induced cardiomyopathy is a major cause of morbidity and mortality in thalassemic patients. Previous studies suggest that cardiac mitochondrial dysfunction may be involved in the pathogenesis of cardiomyopathy in thalassemia. We tested the hypothesis that iron overload causes dysfunction of cardiac mitochondria isolated from thalassemic mice. Cardiac mitochondria were isolated from the heart tissue of genetically-altered, β-thalassemic mice (HT) and adult wild-type mice (WT). Ferrous iron (Fe) at various concentrations (0-5 μg/ml) was applied to induce iron toxicity. Pharmacological interventions, facilitated by mitochondrial permeability transition pore (mPTP) blocker, CsA, and mitochondrial Ca uniporter (MCU) blocker, Ru360, were used to study their respective effects on cardiac mitochondrial dysfunction. Cardiac mitochondrial ROS production, mitochondrial membrane potential changes, and mitochondrial swelling were determined. Iron overload caused increased ROS production, mitochondrial depolarization, and mitochondrial swelling in a dose-dependent manner in WT and HT cardiac mitochondria. CsA decreased only ROS production in WT and HT cardiac mitochondria, whereas Ru360 completely prevented the development of cardiac mitochondrial dysfunction by decreasing ROS, mitochondrial depolarization, and swelling in both WT and HT cardiac mitochondria. Ru360, an MCU blocker, provides protective effects by preventing ROS production and mitochondrial depolarization as well as attenuating mitochondrial swelling caused by Fe overload. These findings indicate that the MCU could be a major portal for Fe entry into cardiac mitochondria. Therefore, blocking MCU may be an effective therapy to prevent iron-overload induced cardiac mitochondrial dysfunction in patients with thalassemia. [ABSTRACT FROM AUTHOR]

Patients with thalassemia, an inherited hemolytic anemia, have increased risk of hypercoagulable complications. A whole blood flow cytometric (FCM) method has been used for studies of platelet activation and platelet-leukocyte aggregation in these patients. However, this FCM method presents technical difficulties because of the high proportion of immature red blood cells (RBCs) in these patients. A protocol for the simultaneous measurement of platelet activation and their aggregation with leukocyte populations in whole blood using four-color FCM which excluded immature RBC was devised, and evaluated for the evaluation of platelet function in patients with β-thalassemia/hemoglobin E (HbE). Whole blood from these patients and from healthy volunteers was stained for platelet activation and platelet-leukocyte aggregates using anti-CD42a, anti-CD62P, anti-CD45 and glycophorin A (GPA) conjugated with different fluorochromes. Our FCM method is simple, effective and based on the assumption that GPA is present on all immature RBCs, but is not expressed on CD45 leukocytes. Results from the studies showed that blood samples from these patients contained a high frequency of circulating activated platelets (CD42a/CD62P) when compared to samples from healthy individuals. The percentage of platelet-neutrophil, platelet-monocyte-but not platelet-lymphocyte-aggregates were also elevated in both thalassemia genotypes with marked increase in patients who had undergone splenectomy. These findings suggest that platelets adhere to neutrophils and monocytes are activated which support the clinical observation that splenectomized thalassemia patients have an increased risk of arterial or venous thrombotic manifestations. [ABSTRACT FROM AUTHOR]

β-thalassemia caused by the C→T mutation at nucleotide 654 of the intron 2 (β) results in aberrant splicing of β-globin RNA, leading to an almost absence of β-globin synthesis. Although trabecular and cortical bone loss was previously reported in β-thalassemic mice with deletion of β-globin gene, the microscopic changes in trabecular structure in β thalassemic mice remained elusive. Here, we investigated the macroscopic and microscopic bone changes in 12-week-old β knockin thalassemic mice by dual-energy X-ray absorptiometry (DXA) and histomorphometric analysis, respectively. DXA revealed a decrease in bone mineral density in the lumbar vertebrae and tibial metaphysis, but not in the femoral diaphysis, suggesting that β thalassemia predominantly led to osteopenia at the trabecular site, but not the cortical site. Further histomorphometric analysis of the tibial secondary spongiosa showed that trabecular bone volume was significantly decreased with the expansion of marrow cavity. Decreases in osteoblast surface, osteoid surface, mineral apposition rate, mineralizing surface, and mineralized volume were also observed. Moreover, trabecular bone resorption was markedly enhanced as indicated by increases in the osteoclast surface and eroded surface. It could be concluded that β thalassemia impaired bone formation and enhanced bone resorption, thereby leading to osteopenia especially at the trabecular sites, such as the tibial metaphysis. [ABSTRACT FROM AUTHOR]

It has long been recognized that the presence of hemoglobin (Hb) Bart's in newborn's blood is associated with α-thalassemia. However, the automated high-performance liquid chromatography or low-performance liquid chromatography system is unable to quantify the amount of Hbs Bart's and H, which are eluted at the retention time close to 0 min. This study used automatic capillary electrophoresis (CE) system to diagnose various types of α-thalassemia in 587 cord blood samples, including 429 normal α-globin genotype, 120 cases of thalassemia with one α-globin gene defect, 34 cases with two α-globin genes defect, and four cases with three α-globin genes defect. The result showed that the level of Hb Bart's in cord blood was increased accordingly with the increasing numbers of the defective α-globin genes. In addition, Hb Bart's level at 0.2%, as measured by CE, can be used as a cut-off point for α-thalassemia diagnosis in newborns. [ABSTRACT FROM AUTHOR]

Erythropoiesis in β-thalassemia patients is ineffective, primarily because of death of the erythroid progenitor cells at the polychromatic normoblast stage. While it is known that autophagy plays a critical role during erythropoiesis by removing organelles from erythroid cells during terminal differentiation, its role in erythroid cells whose function is impaired remains to be explored. To investigate this, CD34+ erythroid progenitor cells from normal controls and β-thalassemia/Hb E patients were isolated from peripheral blood and cultured under conditions driving differentiation into an erythroid lineage, and levels of autophagy and apoptosis were analyzed both directly and after biochemical manipulation with l-asparagine. A significantly higher level of autophagy was seen in β-thalassemia/Hb E erythroblasts as compared to normal control erythroblasts during erythropoiesis. Interestingly, this activation was mediated in part by the presence of high levels of Ca as modulation of Ca levels significantly reduced the level of autophagy in these cells. Inhibition of autophagic flux in normal erythroblasts significantly increased apoptosis in normal erythroblasts, but not in thalassemic erythroblasts, although sensitivity to autophagic flux inhibition was restored by reduction of Ca levels. These results suggest that high levels of autophagy in β-thalassemia/HbE erythroblasts may contribute to the increased levels of apoptosis that lead to ineffective erythropoiesis in β-thalassemia/Hb E erythroblasts. [ABSTRACT FROM AUTHOR]

Background and Objective: Iron-rich transfusions and/or a compensatory increase in iron absorption ultimately result in iron loading in patients with β-thalassaemia. Hence, without iron chelation, iron accumulates relentlessly. Deferiprone has been shown to be capable of reducing the iron burden in patients with β-thalassaemia. However, there is wide interpatient variation in deferiprone-induced urinary iron excretion (UIE). We hypothesized that splenectomy and iron status might influence the pharmacokinetic profiles of deferiprone in patients with β-thalassaemia/haemoglobin E, and the present study was aimed at examining this hypothesis.Study Participants and Methods: Thirty-one patients with β-thalassaemia/haemoglobin E (20 splenectomized and 11 non-splenectomized patients) were enrolled in the study. After an overnight fast, the subjects received a single oral dose of deferiprone 25 mg/kg of bodyweight. Blood samples were collected pre-dosing and at 15, 30, 45, 60, 90, 120, 180, 240, 300, 360 and 480 minutes after dosing. Urine output was pooled and collected at 0-2, 2-4, 4-8, 8-12 and 12-24 hour intervals. Serum and urine concentrations of deferiprone and its metabolite deferiprone glucuronide were determined using a validated high-performance liquid chromatography method. Serum deferiprone-chelated iron and UIE were determined using a validated colourimetric method.Results: No significant difference in the pharmacokinetic parameters of non-conjugated deferiprone was observed between splenectomized and non-splenectomized patients. However, the maximum serum concentration (C(max)) and the area under the serum concentration-time curve (AUC) from time zero to infinity (AUC(∞)) values of deferiprone glucuronide were significantly lower (both p < 0.05) in splenectomized patients (median 53.2 μmol/L and 12 634 μmol • min/L, respectively) than in non-splenectomized patients (median 70.5 μmol/L and 20 601 μmol • min/L, respectively). The C(max) and the AUC from time zero to the time of the last measurable concentration (AUC(last)) values of serum deferiprone-chelated iron, as well as UIE, were significantly higher (p < 0.001) in splenectomized patients (median values 7.1 μmol/L, 1645 μmol • min/L and 77.1 μmol, respectively) than in non-splenectomized patients (median values 3.1 μmol/L, 545 μmol • min/L and 12.5 μmol, respectively). Urinary excretion of non-conjugated deferiprone and deferiprone glucuronide did not differ between the two groups. Further analyses using multiple linear regressions indicated that the iron profiles (non-transferrin-bound iron and ferritin) were significant predictors of the pharmacokinetic parameters of non-conjugated deferiprone, deferiprone-chelated iron and UIE. In addition, splenectomy status was identified as the strongest predictor of the AUC(last) of deferiprone-chelated iron and UIE.Conclusion: Both iron and splenectomy status have significant effects on the pharmacokinetics and iron chelation efficacy of deferiprone. A greater degree of iron overload in splenectomized patients results in alterations in pharmacokinetic parameters (the C(max) and AUC) of deferiprone glucuronide and deferiprone-chelated iron, as well as a significant increase in UIE. [ABSTRACT FROM AUTHOR]

Hemoglobinopathy (abnormal hemoglobin or hemoglobin variant) is an inherited disorder that results in the abnormal structure of globin chains of the hemoglobin (Hb) molecule. Many abnormal Hbs have been characterized worldwide, including more than 20 variants in Thailand. The Bio-Rad Variant II HPLC system is used for investigating hemoglobin variants at Songklanagarind Hospital. This system has been shown to be a sensitive, specific, and reproducible method, but some hemoglobin variants such as Hb Tak and Hb D-Punjab cannot, as yet, be clearly separated by this method. The aim of this study was to investigate the prevalence of hemoglobinopathy in southern Thailand using DNA sequencing and study the severity of each hemoglobin variant. A total of 58 hemoglobin variant samples were obtained from blood samples undergoing routine hemoglobin typing at Songklanagarind Hospital. Genomic DNAs were extracted from the samples, and the globin genes were analyzed by using PCR-direct sequencing. The molecular analysis revealed eight hemoglobin variants: 28 Hb C, 12 Hb D-Punjab, 7 Hb Tak, 4 Hb G-Makassar, 2 Hb Lepore-Hollandia, 2 Hb Q-Thailand, 2 Hb O-Indonesia, and 1 Hb Hope. The distribution of hemoglobin variants in southern Thailand is associated with geographic and/or ethnic backgrounds. This study may help hematologists understand better the prevalence of hemoglobin variants and their hematological features in this region. [ABSTRACT FROM AUTHOR]

MicroRNAs (miRNAs) are negative regulators of gene expression that play an important role in hematopoiesis. Thalassemia, a defective globin synthesis leading to precipitate of excess unbound globins in red blood cell precursors, results in defective erythroid precursors and ineffective erythropoiesis. Expression pattern of miR-451, an erythroid-specific miRNA, was analyzed during differentiation of erythroid progenitors derived from normal and thalassemic peripheral blood CD34-positive cells, after 14 days of culture. A biphasic expression with transient up-regulation of miRNA-451 on day 3 of cultures was observed during thalassemic erythroid differentiation. In contrast, the expression pattern of the miR-451 in erythroid cells obtained from the other extravascular hemolytic anemia, i.e., hereditary spherocytosis patients showed no transient up-regulation of miR-451 on day 3 of cultures. Our results suggest that early erythroid progenitors in β-thalassemia have a dysregulated miRNA-451 expression program, and analysis of microRNA is a relevant approach to determine abnormalities of erythropoiesis. [ABSTRACT FROM AUTHOR]

β-Thalassemia/HbE disease is clinically variable. In searching for genetic factors modifying the disease severity, patients were selected based on their disease severities, and a genome-wide association study (GWAS) was performed. Genotyping was conducted with the Illumina Human 610-Quad BeadChips array using DNAs from 618 Thai β0-thalassemia/HbE patients who were classified as 383 severe and 235 mild phenotypes by a validated scoring system. Twenty-three SNPs in three independent genes/regions were identified as being significantly associated with the disease severity. The highest association was observed with SNPs in the β-globin gene cluster (chr.11p15), and rs2071348 of the HBBP1 gene revealed the most significant association [ P = 2.96 × 10−13, odds ratio (OR) = 4.33 (95% confidence interval (CI), 2.74–6.84)]. The second was identified in the intergenic region between the HBS1L and MYB genes (chr.6q23), among which rs9376092 was the most significant [ P = 2.36 × 10−10, OR = 3.07 (95% CI, 2.16–4.38)]. The third region was located in the BCL11A gene (chr.2p16.1), and rs766432 showed the most significant association [ P = 5.87 × 10−10, OR = 3.06 (95% CI, 2.15–4.37)]. All three loci were replicated in an independent cohort of 174 Indonesian patients. The associations to fetal hemoglobin levels were also observed with SNPs on these three regions. Our data indicate that several genetic loci act in concert to influence HbF levels of β0-thalassemia/HbE patients. This study revealed that all the three reported loci and the α-globin gene locus are the best and common predictors of the disease severity in β-thalassemia. [ABSTRACT FROM AUTHOR]

Finding gene interaction models is one of the most important issues in genotype–phenotype association studies. This paper presents a model-free nonparametric statistical interaction analysis known as Parallel Haplotype Configuration Reduction (pHCR). This technique extends the original Multifactor Dimensionality Reduction (MDR) algorithm by using haplotype contribution values (c-values) and a haplotype interaction scheme instead of analyzing interactions among single-nucleotide polymorphisms. The proposed algorithm uses the statistical power of haplotypes to obtain a gene–gene interaction model. pHCR computes a statistical value for each haplotype, which contributes to the phenotype, and then performs haplotype interaction analysis on the basis of the cumulative c-value of each individual haplotype. To address the high computational complexity of pHCR, this paper also presents a scalable parallel computing solution. Nine common two-locus disease models were used to evaluate the algorithm performance under different scenarios. The results from all cases showed that pHCR shows higher power to detect gene–gene interaction in comparison with the results obtained from running MDR on the same data set. We also compared pHCR with FAMHAP, which mainly considers haplotype in the association analysis. For every experiment on the simulated data set, pHCR correctly produced haplotype interactions with much fewer false positives. We also challenged pHCR with a real data set input of β-thalassemia/Hemoglobin E (HbE) disease. The result suggested the interaction between two previously reported quantitative trait loci of the fetal hemoglobin level, which is a major modifying factor, and disease severity of β-thalassemia/HbE disease. [ABSTRACT FROM AUTHOR]

Increase in fetal hemoglobin (Hb F) reduces globin chain imbalance in beta-thalassemia, consequently improving symptoms. QTL mapping together with previous genome-wide association study involving approximately 110,000 gene-based SNPs in mild and severe beta(0)-thalassemia/Hb E patients revealed SNPs in HBS1L significantly associated with severity and Hb F levels. Given its potential as binding site for transcription factor activator protein 4, HBS1L exon 1 C32T polymorphism was genotyped in 455 cases, providing for the first time evidence that C allele is associated with elevated Hb F level among beta(0)-thalassemia/Hb E patients with XmnI-(G)gamma-/-and XmnI-(G)gamma+/-polymorphisms. [ABSTRACT FROM AUTHOR]

A β-thalassaemia mutation occurring from insertion of a duplicated 22-bp intron/exon junction of the β-globin gene has been characterised. The repeated 22-bp insertion causes duplication of a 3′ splice site at IVSI/exon 2 junction. Reverse transcription–polymerase chain reaction showed that the proximal 3′ splice site present in the duplicated gene is used, leading to a frameshift and a premature chain termination at codon 37. β-Globin messenger ribonucleic acid (mRNA) transcribed from the mutant gene was not detected, suggesting that the process of nonsense-mediated mRNA decay may be triggered by the premature stop codon. [ABSTRACT FROM AUTHOR]

β-Thalassemia/Hb E patients show a range of clinical severities, from nearly asymptomatic to transfusion-dependent thalassemia major. This study investigated the clinical heterogeneity and hematologic parameters obtained in the large cohort of 925 Thai β0-thalassemia/Hb E patients. Coinheritance of α-thalassemia with β0-thalassemia/Hb E produces a milder clinical phenotype in contrast to an interaction of α-globin gene triplication in severe thalassemia. The mean steady-state Hb was also higher, whereas the mean corpuscular volume and the percentage of Hb F were markedly lower in the former group. This finding demonstrates that the genetic combination leading to the more/less degree of α- to non-α-globin chains imbalance is indeed the cause of the severe/mild thalassemia phenotype. [ABSTRACT FROM AUTHOR]

In thalassemia, deficient globin-chain production during erythropoiesis results in anemia. Thalassemia may be further complicated by iron overload (frequently exacerbated by blood transfusion), which induces numerous endocrine diseases, hepatic cirrhosis, cardiac failure and even death. Accumulation of iron in the absence of blood transfusions may result from inappropriate suppression of the iron-regulating peptide hepcidin by an erythropoietic mechanism. To test this hypothesis, we examined erythroblast transcriptome profiles from 15 healthy, nonthalassemic donors. Growth differentiation factor 15 (GDF15), a member of the transforming growth factor-β superfamily, showed increased expression and secretion during erythroblast maturation. Healthy volunteers had mean GDF15 serum concentrations of 450 ± 50 pg/ml. In comparison, individuals with β-thalassemia syndromes had elevated GDF15 serum levels (mean 66,000 ± 9,600 pg/ml; range 4,800–248,000 pg/ml; P < 0.05) that were positively correlated with the levels of soluble transferrin receptor, erythropoietin and ferritin. Serum from thalassemia patients suppressed hepcidin mRNA expression in primary human hepatocytes, and depletion of GDF15 reversed hepcidin suppression. These results suggest that GDF15 overexpression arising from an expanded erythroid compartment contributes to iron overload in thalassemia syndromes by inhibiting hepcidin expression. [ABSTRACT FROM AUTHOR]

Thalassemia may alter the pharmacokinetics of several drugs in thalassemic patients. Paracetamol is a commonly used analgesic and antipyretic drug which is extensively metabolized in the liver via glucuronidation. The aim of this study was to compare the pharmacokinetics of paracetamol (PCM) and its metabolites [paracetamol glucuronide (PCM-G), paracetamol sulfate (PCM-S), and paracetamol cysteine (PCM-C)] in 16 patients with 16 normal subjects. Following an overnight fast, a single dose of paracetamol (1,000 mg of Tylenol®) was given and blood samples were obtained at predose, 0.5, 1, 1.5, 2, 3, 4, 5, 7, and 9 h after dosing for determination of the plasma levels of PCM and its metabolites by high-performance liquid chromatography. There was no significant difference in maximum concentration of PCM between groups. However, a significantly shorter elimination half-life of PCM was observed in the thalassemic subjects ( p<0.001). Total apparent clearance of PCM was significantly faster in thalassemic subjects ( p<0.01) while the apparent volume of distribution of PCM did not change. The area under the concentration time curve (AUC0->∞) of PCM-G and PCM-S increased in thalassemic subjects ( p<0.05) whereas this parameter for PCM-C was slightly lower in the patients. The half-lives of PCM metabolites were significantly shorter ( p<0.01) in thalassemic subjects. The results indicate that the elimination of PCM and its metabolites in thalassemic subjects is faster than that in normal subjects. Our pharmacokinetic data provide additional evidence that plasma PCM-G is higher in thalassemic patients with hyperbilirubinemia, which could be a casual relationship in regulating the UDP-glucuronosyltransferase expression. [ABSTRACT FROM AUTHOR]

Immunoglobulin Y (IgY) technology was used to generate anti-hemoglobin Bart's (Hb Bart's) IgY antibodies (Abs) for development into an enzyme-linked immunosorbent assay (ELISA) test for thalassemia diagnosis. Hb Bart's purified from the hemolysate of a patient with Hb Bart's hydrops fetalis (homozygous alpha-thalassemia) was used to immunize a chicken via the pectoralis muscle. After water dilution and sodium sulfate precipitation, 40 to 70 mg of IgY could be extracted from an egg. IgY, first detected in sera 2 weeks after immunization, reached the highest titer at week 4, and the titer remained stable for at least 2 weeks before declining. The pattern of Ab response in the yolk was the same as in the serum but was somewhat delayed. The IgY Abs produced reacted with gamma globin, Hb Bart's, Hb F, normal cord hemolysate (Hbs F plus A), and Hb Bart's hydrops fetalis (Hbs Bart's plus Portland) and to a lesser degree with beta globin, Hb A, Hb A2 and adult hemolysate (Hbs A plus A2), but the Abs did not react with alpha globin. Immunoaffinity purification with Hb A coupled to Sepharose was used to isolate an unbound IgY that reacted with Hb F, Hb Bart's, and gamma globin, and this IgY was used to develop an ELISA test for thalassemia diagnosis. The results of direct ELISA analyses of 336 hemolysate samples from individuals with various known thalassemia genotypes and phenotypes and from healthy individuals confirmed the specificity of the polyclonal Abs for Hbs containing Hb F and Hb Bart's. This specificity, which was due to the Abs' strong reactivity in cases of pathologic thalassemic diseases and weak reactivity in cases of nonpathologic thalassemic diseases, depended on the levels of Hb Bart's and Hb F. [ABSTRACT FROM AUTHOR]

Hereditary persistence of fetal hemoglobin (HPFH) is associated with a high level of hemoglobin F (HbF) synthesis in adult heterozygotes. In this study, 2 of 6 unrelated HPFH Thai families were found to be Southeast Asian-type HPFH (SEA-HPFH) by analyses of the hematologic data and Southern blot hybridization with polymerase chain reaction-amplified DNA probes. DNA mapping with a probe for a delta-globin fragment showed a 27-kb deletion of DNA that included the beta-globin gene and the 3' deoxyribonuclease I hypersensitive site 1 (3'HS1) sequence downstream. Deletion of the insulator, 3'HS1, and the juxta-position of the HPFH-3 core enhancer downstream to the 3' breakpoint have been postulated to be the cause of high HbF production in these individuals. To test this hypothesis, we transfected K562 cells with 4 different bacterial artificial chromosome constructs containing the enhanced green fluorescent protein (EGFP) gene at the position of the Agamma-globin gene (pEBAC/148beta:EGFP). Flow cytometry was used to compare EGFP expression from the pEBAC/148beta:EGFP construct with the HPFH-3 core enhancer immediately 5' to the SEA-HPFH breakpoint (pEnH), from the pEBAC/148beta:EGFP construct with 8 kb of the breakpoint sequence and the HPFH-3 core enhancer (pSEA-HPFH), and from the construct with 3'HS1 followed by the pSEA-HPFH sequence (pSEA-HPFH_3pHS1). The results show that high HbF production in SEA-HPFH occurs from a deletion of the 3'HS1 sequence and the juxtaposition of the HPFH-3 enhancer downstream to the delta-globin gene. [ABSTRACT FROM AUTHOR]

Due to genetic heterogeneity of β-thalassemia (β-thal) patients, several efforts have been undertaken to determine the efficacy of hydroxyurea treatment. The aim of this work is to determine the responder and nonresponder for hydroxyurea treatment in β-thal intermedia based on γ-globin mRNA and fetal hemoglobin (HbF) induction in human erythroid progenitor cells purified from a patient’s peripheral blood. Eighteen β-thal/hemoglobin E patients [13 βE/codon41/42(-TCTT), 4 βE/codon17, and 1 βE/IVS-654], requiring blood transfusion occasionally, with Hb levels of 5.20–8.50 g/dl were studied. The relative levels of γ-globin mRNA was measured by real-time reverse-transcription polymerase chain reaction and HbF by high-performance liquid chromatography. The results indicated that erythroid progenitor cells treated with 30 μmol/l hydroxyurea for 96 h preferentially enhanced Gγ-and Aγ-globin mRNA. The mean values of Gγ-globin mRNA fold induction were higher than Aγ-globin mRNA (12±4 vs 4±0.30), the Pearson’s correlation of Gγ-and Aγ-globin mRNA was r=0.80. Induction of Gγ/Aγ globin mRNA is up to ninefold. A 30% increase in the proportion of HbF out of the total Hb was found in cultures derived from four patients, 20–30% in cultures from nine patients, and less than 20% in cultures from five patients. In cultures from only two patients, increase in the proportion of HbF was less than 3%, and Gγ/Aγ globin mRNA is less than 0.50. [ABSTRACT FROM AUTHOR]

Hemoglobin (Hb) Bart's hydrops fetalis, the most severe thalassemic disease, occurs from homozygosity of alpha-thalassemia 1. Deletion of all 4 alpha-globin genes (- -/- -) in this condition results in the absence of alpha-globin chains, and the physiologic dysfunction of Hb Bart's (gamma4) leads to lethality, either in utero or soon after birth. The best strategy for prevention and control of the disease is prenatal diagnosis in the mothers at risk. However, conventional prenatal diagnosis involves invasive procedures that may result in infection or abortion. In this study, a simple technique was developed to identify the presence or absence of alpha-globin chains in fetal nucleated red blood cells (NRBCs) enriched from maternal blood. Mononuclear cells including fetal NRBCs were isolated from maternal blood at 10 to 26 weeks of pregnancy by density-gradient centrifugation. Immunomagnetic separation with anti-CD71 antibody was employed to enrich fetal NRBCs, whose numbers increase with increasing gestational age. For the unaffected fetus, fetal NRBCs were detected by immunofluorescence microscopy after staining with rabbit antihuman alpha-globin antibody. In contrast, fetal red blood cells homozygous for alpha-thalassemia 1, which were identified from their size and morphology, did not stain for alpha-globin antibody. In this study, 3 affected fetuses were detected from 10 pregnancies at risk of Hb Bart's hydrops fetalis, and the results were confirmed by DNA analysis. In the remaining cases, all fetal NRBCs were positive for immunofluorescence staining. DNA analysis revealed that 2 cases were normal, 1 was heterozygous for alpha-thalassemia 2, and the other 4 cases were heterozygous for alpha-thalassemia 1. [ABSTRACT FROM AUTHOR]

Interferon (IFN)-gamma is a survival factor for mature erythroid progenitor cells. To elucidate related survival mechanisms, we compared the role of phosphatidylinositol 3-kinase (PI3-kinase) in the survival signals of IFN-gamma and erythropoietin (EPO). Human erythroid colony-forming cells (ECFCs) purified from peripheral blood were used, and Ly294002 was used as a PI3-kinase inhibitor. Treating ECFCs with a high concentration of Ly294002 (50 micromol/L) in the presence of EPO and/or IFN-gamma reduced cell viability by inducing apoptosis. However, treating cells with a lower concentration of Ly294002 (10 micromol/L) did not affect the antiapoptotic function of IFN-gamma and abolished the antiapoptotic effect of EPO. Adding IFN-gamma or EPO induced Bcl-x expression in ECFCs, as determined by Western blotting, and expression was suppressed in the presence of Ly294002. We also examined the phosphorylation of the protein kinase Akt, the downstream target of PI3-kinase. EPO stimulation significantly increased the level of Akt phosphorylation, but IFN-gamma did not. These results suggest that IFN-gamma plays a role in preventing the apoptosis of erythroid progenitor cells by affecting Bcl-x expression, thereby reducing the disruption of the mitochondrial transmembrane potential via PI3-kinase pathways that are related to but distinct from the EPO pathway. [ABSTRACT FROM AUTHOR]

Hepatitis C virus (HCV) infection is a common cause of liver disease in thalassemia major patients in Western, especially Mediterranean, countries. Its significance in thalassemic patients from Southeast Asia has not been critically evaluated. In this report, we describe our study of the prevalence of HCV infection among Thai patients with thalassemia. The relationships of the infection to blood transfusion and the infection's effects on liver function have also been determined. Of the 104 patients studied, 21 (20.2%) tested positively by enzyme immunoassay for anti-HCV antibody, whereas only 2 patients (2%) had the hepatitis B surface antigen. There was no significant relationship between the presence of anti-HCV antibodies and the number and frequency of blood transfusions. In fact, 2 patients (10%) who tested positive for anti-HCV antibodies had never received transfusions. Patients with anti-HCV antibodies had significantly abnormal liver functions, such as higher levels of serum aspartate aminotransferase (SGOT) and alanine aminotransferase (SGPT) and lower levels of serum albumin, compared with patients without anti-HCV antibodies (P = .021, .017, and .004, respectively). However, there were also significant correlations between iron status as indicated by transferrin saturation or serum ferritin levels and SGOT, SGPT, and gamma-glutamyltransferase (GGT) levels. Moreover, abnormal liver function as represented by elevated levels of SGOT, SGPT, GGT, and serum alkaline phosphatase was observed more frequently in patients with iron overload than in patients with a lower degree of iron burden. The presence of HCV did not alter the effects of iron overload on liver function. The findings suggest that both HCV and iron overload are the main causes of abnormal liver function in Thai patients with thalassemia. The treatment of both problems, if coexisting in patients with thalassemia, is required to prevent progression to chronic liver disease. [ABSTRACT FROM AUTHOR]

Thalassemia and abnormal hemoglobins are common genetic disorders in Asia. Thalassemia is not only an important public health problem but also a socio-economic problem of many countries in the region. The approach to deal with the thalassemic problem is to prevent and control birth of new cases. This requires an accurate identification of the couple at high risk for thalassemia. However, the diagnosis of thalassemia carrier states need several tests which are not practical for screening the population at large. Recently we have used two simple laboratory tests to screen for potential thalassemia carriers and hemoglobin E individuals. There is also a new development in using the automatic HPLC to diagnose thalassemic diseases and the carriers. This system gives both qualitative and quantitative analysis of hemoglobin components in the same run with good precision and reproducibility. The system has been applied to study thalassemia and abnormal Hb in adult and cord blood. This system has enabled us to do both prenatal and postnatal diagnosis of thalassemia within the few minutes. However, none of these screening tests can accurately give specific diagnosis of the thalassemia genotype. Specific thalassemia mutation can be carried out by DNA analysis. Many DNA techniques have been used for point mutation detection and small deletion. For the last few years there is a development of DNA chip technology that has been applied for thalassemia mutation as well. Clinically, thalassemia is very heterogeneous in the manifestation. In spite of seemingly identical genotypes, severity of beta thalassemic patients can vary greatly. Heterogeneity in the clinical manifestation of beta thalassemic diseases may occur from the nature of beta globin gene mutation, alpha thalassemia gene interaction and difference in the amount of Hb F production which is partly associated with a specific beta globin haplotype. However, there is still some beta thalassemia cases that have a mild clinical symptom without those known genetic fators interaction suggesting that there are other additional factors responsible for the mildness of the disease. [ABSTRACT FROM AUTHOR]

Sera from thalassaemic individuals were experimentally tested for their suppressive effects on the in vitro development of asexual stages of Plasmodium falciparum. Cultures in sera collected from six patients who had classical haemoglobin H disease (α-thal-α-thal) and six patients who had haemoglobin H disease with haemoglobin (Hb) Constant Spring (α-thal-CS) showed a significantly higher degree of inhibition of parasite multiplication than cultures of thalassaemic erythrocytes in sera from healthy individuals. Similarly, sera from 12 patients with β-thalassaemia/haemoglobin E (β-thal-HbE) diminished parasite development in vitro. Schizonts of P. falciparum cultured in erythrocytes from non-thalassaemic individuals containing normal Hb (αβ) were also inhibited when thalassaemic serum was used in place of normal serum. The degree of inhibition was proportional to the concentration (vol/vol) of the thalassaemic serum. [ABSTRACT FROM AUTHOR]

Enzymatic DNA amplification and polyacrylamide gel electrophoresis, which demonstrate different sizes of DNA fragments, were used to detect the common mutations causing β-thalassemia and hemoglobin (Hb) E in Thai people. The 4-bp deletion at codons 41 and 42 can be detected directly by polyacrylamide gel electrophoresis and ethidium bromide staining. Whereas the nonsense mutations at codon 17 (AAG →TAG) and Hb E (GAG→AAG at codon 26) were detected after digestion of the amplified DNA with the enzymes MaeI and MnlI, respectively. [ABSTRACT FROM AUTHOR]