Search Results (54)

Background: FGF23 is a phosphate homeostasis regulator; the literature suggests a link between FGF23, iron homeostasis and erythropoiesis. Little is known about the FGF23 level variations in β-thalassemia (βT), which is characterized by ineffective erythropoiesis and iron overload. Our cross-sectional study aims to evaluate the iFGF23 level variations in a large cohort of βT patients considering their bone mineral densities (BMDs) and iron loads. Methods: Clinical, biochemical and radiological data were collected from 213 transfusion-dependent βT (TDT) adults referring to the Regional HUB Centre for Thalassaemia and Haemoglobinopathies in Ferrara, Italy. The iFGF23 levels in the TDT patients were compared to the general population’s reference range. The BMDs and hearth and liver iron deposits were assessed with DEXA scans and MRI, respectively. Results: The iFGF23 distribution in the TDT subjects is significantly different from that of the general population. The iFGF23 levels are positively correlated with the age at transfusion initiation and calcium and phosphate levels and are negatively correlated with the osteocalcin plasma levels. Patients treated with deferasirox had lower iFGF23 levels than those treated with other chelators. The iFGF23 levels are not correlated with the BMD or iron status. Conclusions: These findings provide insights into the relationship between the iFGF23 and bone and iron metabolism in TDT patients. Further studies are needed to explore its potential clinical relevance. Full article

The inherited genetic disorder β-thalassemia affects the hematopoietic system and is caused by the low production or absence of adult hemoglobin (HbA). Ineffective erythropoiesis is the hallmark of β-thalassemia pathophysiology and is characterized by an erythropoietin-driven substantial increase in erythroblast proliferation, coupled with an increase in late-stage precursor apoptosis, which results in low levels of circulating mature red blood cells (RBCs) and chronic anemia. Mitochondrial dysfunction commonly occurs in these cells because of the increased demand for energy production and the need to manage abnormal hemoglobin chain synthesis. Moreover, several studies have highlighted the importance of gradual mitochondrial clearance for mature erythroid cell production. This review offers an overview of the mitochondrial role in essential cellular processes, particularly those crucial for maintaining RBC health and function. Additionally, recent evidence regarding the contribution of mitochondrial dysfunction to the pathophysiology and severity of β-thalassemia is discussed, along with updated insights into indirect mitochondria-targeting treatments, which present potential pharmacological targets. Full article

β-thalassemia is one of the most prevalent single-gene recessive disorders worldwide, characterized by the impaired synthesis of β-globin chains, which leads to ineffective erythropoiesis and results in anemia and iron overload, along with various complications. Therefore, establishing animal models that closely resemble β-thalassemia is essential for studying the pathogenesis and treatment of this disease. This article reviews the molecular mechanisms underlying β-thalassemia; highlights the research advancements of several common clinical treatment methods; and provides a summary of prevalent animal models of β-thalassemia, including mice, rabbits, and cynomolgus monkeys. Although the mouse model reproduces certain pathological characteristics of β-thalassemia, it is limited in its ability to correct specific gene mutations, making it less effective for certain aspects of the disease. In contrast, the rabbit model, which more closely resembles human physiology, offers an improved approximation. Furthermore, the cynomolgus monkey model outperforms both the mouse and rabbit models in exhibiting the severe phenotype of β-thalassemia, thanks to its notable genetic and physiological similarities to humans. This article aims to provide a comprehensive reference for researchers conducting animal experimental studies in relation to β-thalassemia. Full article

Despite a decrease in prevalence and incidence rates, beta thalassemia continues to represent a significant public health challenge worldwide. In high-resource settings, children with thalassemia have an open prognosis, with a high chance of reaching adulthood and old age with a good quality of life. This is achievable if transfusion therapy is properly managed, effectively mitigating ineffective erythropoiesis and its associated complications while also minimizing excessive iron accumulation. Adequate iron chelation is essential to maintain reactive forms of iron within the normal range throughout life, thus preventing organ damage caused by hemosiderosis, which inevitably results from a regular transfusion regimen. New therapies, both curative, such as gene therapy, and non-curative, such as modulators of erythropoiesis, are becoming available for patients with transfusion-dependent beta thalassemia. Two curative approaches based on gene therapy have been investigated in both adults and children with thalassemia. The first approach uses a lentivirus to correct the genetic defect, delivering a functional gene copy to the patient’s cells. The second approach employs CRISPR/Cas9 gene editing to directly modify the defective gene at the molecular level. No non-curative therapies have received approval for pediatric use. Among adults, the only available drug is luspatercept, which is currently undergoing clinical trials in pediatric populations. However, in many countries around the world, the new therapeutic options remain a mirage, and even transfusion therapy itself is not guaranteed for most patients, while the choice of iron chelation therapy depends on drug availability and affordability. Full article

Thalassemia represents a diverse group of inherited hematological disorders characterized by defective globin chain synthesis, leading to chronic anemia and associated complications. The complicated pathophysiology of beta-thalassemia involves genetic mutations or rarely deletions of the beta-globin gene on chromosome 11 whereas alpha-thalassemia involves deletions in the HBA1 and HBA2 genes or occasionally alterations to the DNA sequence in or around these genes. These mutation and deletion effects disrupt the balance of α/β-globin chain production, resulting in ineffective erythropoiesis, hemolysis, and a cascade of clinical manifestations including anemia, bone deformities, and iron overload. Advances in diagnostic techniques have enhanced our ability to detect and characterize these mutations, facilitating early and accurate diagnoses. Current management strategies encompass regular blood transfusions, the use of hydroxyurea to improve hemoglobin levels, and iron chelation therapy to prevent iron-related organ damage. Moreover, other therapeutics such as thalidomide for those not responding to hydroxyurea, Sirolimus for patients with immunodeficiencies, and use of vitamin E as an antioxidant have proven to be effective. Innovative therapies such as gene therapy and bone marrow transplantation offer promising curative potential, opening a new era in the treatment of thalassemia. This review focuses on pathophysiological mechanisms underlying thalassemia, explores the diagnostic methodologies, and highlights recent advancements in therapeutic approaches. Full article

Over the last few years, several mechanisms that are involved in congenital diseases characterized by ineffective erythropoiesis have been described. Therefore, multiple new target drugs are being developed in preclinical models against the main regulators of normal erythropoiesis. Above all, the key mechanism that regulates systemic iron homeostasis, represented by the hepcidin–ferroportin axis, is considered to be the target for new therapies. The main hypothesis is that iron restriction, through blocking ferroportin (the unique iron transporter in mammals) in such diseases, ameliorates erythropoiesis. The action of vamifeport is different from the currently approved drugs in this setting since it acts straight on the ferroportin–hepcidin axis. The data presented in the sickle cell disease (SCD) Townes mouse model showed a preclinical proof-of-concept for the efficacy of oral ferroportin inhibitor. Vamifeport reduced hemoglobin concentration in red blood cells (RBCs) and diminished intravascular hemolysis and inflammation, improving hemodynamics and preventing vascular occlusive crises. On this basis, clinical trials were commenced in patients with SCD, non-transfusion-dependent (NTD) thalassemia and transfusion-dependent (TD) thalassemia. Preliminary data in NTD thalassemic patients also confirm the safety and efficacy in decreasing iron level. In conclusion, vamifeport represents a new option in the panorama of drugs targeting the hepcidin–ferroportin axis, but its efficacy is still under investigation as a single agent. Full article

Severe malarial anemia (SMA) increases the morbidity and mortality of Plasmodium, the causative agent of malaria. SMA is mainly developed by children and pregnant women in response to the infection. It is characterized by ineffective erythropoiesis caused by impaired erythropoietin (EPO) signaling. To gain new insights into the pathogenesis of SMA, we investigated the relationship between the immune system and erythropoiesis, conducting comparative analyses in a mouse model of malaria. Red blood cell (RBC) production was evaluated in infected and reinfected animals to mimic endemic occurrences. Higher levels of circulating EPO were observed in response to (re)infection. Despite no major differences in bone marrow erythropoiesis, compensatory mechanisms of splenic RBC production were significantly reduced in reinfected mice. Concomitantly, a pronounced immune response activation was observed in erythropoietic organs of reinfected animals in relation to single-infected mice. Aged mice were also used to mimic the occurrence of malaria in the elderly. The increase in symptom severity was correlated with the enhanced activation of the immune system, which significantly impaired erythropoiesis. Immunocompromised mice further support the existence of an immune-shaping regulation of RBC production. Overall, our data reveal the strict correlation between erythropoiesis and immune cells, which ultimately dictates the severity of SMA. Full article

The β-thalassemias are inherited genetic disorders affecting the hematopoietic system. In β-thalassemias, more than 350 mutations of the adult β-globin gene cause the low or absent production of adult hemoglobin (HbA). A clinical parameter affecting the physiology of erythroid cells is the excess of free α-globin. Possible experimental strategies for a reduction in excess free α-globin chains in β-thalassemia are CRISPR-Cas9-based genome editing of the β-globin gene, forcing “de novo” HbA production and fetal hemoglobin (HbF) induction. In addition, a reduction in excess free α-globin chains in β-thalassemia can be achieved by induction of the autophagic process. This process is regulated by the Unc-51-like kinase 1 (Ulk1) gene. The interplay with the PI3K/Akt/TOR pathway, with the activity of the α-globin stabilizing protein (AHSP) and the involvement of microRNAs in autophagy and Ulk1 gene expression, is presented and discussed in the context of identifying novel biomarkers and potential therapeutic targets for β-thalassemia. Full article

Erythropoiesis is initiated with the transformation of multipotent hematopoietic stem cells into committed erythroid progenitor cells in the erythroblastic islands of the bone marrow in adults. These cells undergo several stages of differentiation, including erythroblast formation, normoblast formation, and finally, the expulsion of the nucleus to form mature red blood cells. The erythropoietin (EPO) pathway, which is activated by hypoxia, induces stimulation of the erythroid progenitor cells and the promotion of their proliferation and survival as well as maturation and hemoglobin synthesis. The regulation of erythropoiesis is a complex and dynamic interaction of a myriad of factors, such as transcription factors (GATA-1, STAT5), cytokines (IL-3, IL-6, IL-11), iron metabolism and cell cycle regulators. Multiple microRNAs are involved in erythropoiesis, mediating cell growth and development, regulating oxidative stress, erythrocyte maturation and differentiation, hemoglobin synthesis, transferrin function and iron homeostasis. This review aims to explore the physiology of steady-state erythropoiesis and to outline key mechanisms involved in ineffective erythropoiesis linked to anemia, chronic inflammation, stress, and hematological malignancies. Studying aberrations in erythropoiesis in various diseases allows a more in-depth understanding of the heterogeneity within erythroid populations and the development of gene therapies to treat hematological disorders. Full article

Background/Objectives: in β-thalassemia, important clinical complications are caused by the presence of free α-globin chains in the erythroid cells of β-thalassemia patients. These free α-globin chains are present in excess as a result of the lack of β-globin chains to bind with; they tend to aggregate and precipitate, causing deleterious effects and overall cytotoxicity, maturation arrest of the erythroid cells and, ultimately, ineffective erythropoiesis. The chaperone protein α-hemoglobin-stabilizing protein (AHSP) reversibly binds with free α-globin; the resulting AHSP-αHb complex prevents aggregation and precipitation. Sirolimus (rapamycin) has been previously demonstrated to induce expression of fetal hemoglobin and decrease the excess of free α-globin chain in the erythroid cells of β-thalassemia patients. The objective of this study was to verify whether sirolimus is also able to upregulate AHSP expression in erythroid precursor cells (ErPCs) isolated from β-thalassemia patients. Methods: the expression of AHSP genes was analyzed by measuring the AHSP mRNA content by real-time quantitative PCR (RT-qPCR) and the AHSP protein production by Western blotting. Results: AHSP gene expression was found to be higher in ErPCs of β-thalassemia patients in comparison to ErPCs isolated from healthy subjects. In addition, AHSP expression was further induced by treatment of β-thalassemia ErPCs with sirolimus. Finally, AHSP mRNA was expressed at an increased level in ErPCs of sirolimus-treated β-thalassemia patients participating in the NCT03877809 Sirthalaclin clinical trial. Conclusions: this exploratory study suggests that AHSP expression should be considered as an endpoint in clinical trials based on sirolimus. Full article

Aging is characterized by increased oxidation and reduced efficiency of cytoprotective mechanisms. Nuclear factor erythroid-2-related factor (Nrf2) is a key transcription factor, controlling the expression of multiple antioxidant proteins. Here, we show that Nrf2^−/− mice displayed an age-dependent anemia, due to the combined contributions of reduced red cell lifespan and ineffective erythropoiesis, suggesting a role of Nrf2 in erythroid biology during aging. Mechanistically, we found that the expression of antioxidants during aging is mediated by activation of Nrf2 function by peroxiredoxin-2. The absence of Nrf2 resulted in persistent oxidation and overactivation of adaptive systems such as the unfolded protein response (UPR) system and autophagy in Nrf2^−/− mouse erythroblasts. As Nrf2 is involved in the expression of autophagy-related proteins such as autophagy-related protein (Atg) 4-5 and p62, we found impairment of late phase of autophagy in Nrf2^−/− mouse erythroblasts. The overactivation of the UPR system and impaired autophagy drove apoptosis of Nrf2^−/− mouse erythroblasts via caspase-3 activation. As a proof of concept for the role of oxidation, we treated Nrf2^−/− mice with astaxanthin, an antioxidant, in the form of poly (lactic-co-glycolic acid) (PLGA)-loaded nanoparticles (ATS-NPs) to improve its bioavailability. ATS-NPs ameliorated the age-dependent anemia and decreased ineffective erythropoiesis in Nrf2^−/− mice. In summary, we propose that Nrf2 plays a key role in limiting age-related oxidation, ensuring erythroid maturation and growth during aging. Full article

Thalassemia represents one of the most common genetic disorders worldwide, characterized by defects in hemoglobin synthesis. The affected individuals suffer from malfunctioning of one or more of the four globin genes, leading to chronic hemolytic anemia, an imbalance in the hemoglobin chain ratio, iron overload, and ineffective erythropoiesis. Despite the challenges posed by this condition, recent years have witnessed significant advancements in diagnosis, therapy, and transfusion support, significantly improving the prognosis for thalassemia patients. This research empirically evaluates the efficacy of models constructed using classification methods and explores the effectiveness of relevant features that are derived using various machine-learning techniques. Five feature selection approaches, namely Chi-Square (χ2), Exploratory Factor Score (EFS), tree-based Recursive Feature Elimination (RFE), gradient-based RFE, and Linear Regression Coefficient, were employed to determine the optimal feature set. Nine classifiers, namely K-Nearest Neighbors (KNN), Decision Trees (DT), Gradient Boosting Classifier (GBC), Linear Regression (LR), AdaBoost, Extreme Gradient Boosting (XGB), Random Forest (RF), Light Gradient Boosting Machine (LGBM), and Support Vector Machine (SVM), were utilized to evaluate the performance. The χ2 method achieved accuracy, registering 91.56% precision, 91.04% recall, and 92.65% f-score when aligned with the LR classifier. Moreover, the results underscore that amalgamating over-sampling with Synthetic Minority Over-sampling Technique (SMOTE), RFE, and 10-fold cross-validation markedly elevates the detection accuracy for αT patients. Notably, the Gradient Boosting Classifier (GBC) achieves 93.46% accuracy, 93.89% recall, and 92.72% F1 score. Full article

The β-thalassemias are hereditary monogenic diseases characterized by a low or absent production of adult hemoglobin and excess in the content of α-globin. This excess is cytotoxic for the erythroid cells and responsible for the β-thalassemia-associated ineffective erythropoiesis. Therefore, the decrease in excess α-globin is a relevant clinical effect for these patients and can be realized through the induction of fetal hemoglobin, autophagy, or both. The in vivo effects of sirolimus (rapamycin) and analogs on the induction of fetal hemoglobin (HbF) are of key importance for therapeutic protocols in a variety of hemoglobinopathies, including β-thalassemias. In this research communication, we report data showing that a decrease in autophagy-associated p62 protein, increased expression of ULK-1, and reduction in excess α-globin are occurring in erythroid precursors (ErPCs) stimulated in vitro with low dosages of sirolimus. In addition, increased ULK-1 mRNA content and a decrease in α-globin content were found in ErPCs isolated from β-thalassemia patients recruited for the NCT03877809 clinical trial and treated with 0.5–2 mg/day sirolimus. Our data support the concept that autophagy, ULK1 expression, and α-globin chain reduction should be considered important endpoints in sirolimus-based clinical trials for β-thalassemias. Full article

Congenital dyserythropoietic anemia type II (CDA II) is an inherited autosomal recessive blood disorder which belongs to the wide group of ineffective erythropoiesis conditions. It is characterized by mild to severe normocytic anemia, jaundice, and splenomegaly owing to the hemolytic component. This often leads to liver iron overload and gallstones. CDA II is caused by biallelic mutations in the SEC23B gene. In this study, we report 9 new CDA II cases and identify 16 pathogenic variants, 6 of which are novel. The newly reported variants in SEC23B include three missenses (p.Thr445Arg, p.Tyr579Cys, and p.Arg701His), one frameshift (p.Asp693GlyfsTer2), and two splicing variants (c.1512-2A>G, and the complex intronic variant c.1512-3delinsTT linked to c.1512-16_1512-7delACTCTGGAAT in the same allele). Computational analyses of the missense variants indicated a loss of key residue interactions within the beta sheet and the helical and gelsolin domains, respectively. Analysis of SEC23B protein levels done in patient-derived lymphoblastoid cell lines (LCLs) showed a significant decrease in SEC23B protein expression, in the absence of SEC23A compensation. Reduced SEC23B mRNA expression was only detected in two probands carrying nonsense and frameshift variants; the remaining patients showed either higher gene expression levels or no expression changes at all. The skipping of exons 13 and 14 in the newly reported complex variant c.1512-3delinsTT/c.1512-16_1512-7delACTCTGGAAT results in a shorter protein isoform, as assessed by RT-PCR followed by Sanger sequencing. In this work, we summarize a comprehensive spectrum of SEC23B variants, describe nine new CDA II cases accounting for six previously unreported variants, and discuss innovative therapeutic approaches for CDA II. Full article

Erythropoiesis is a highly regulated process and undergoes several genotypic and phenotypic changes during differentiation. The phenotypic changes can be evaluated using a combination of cell surface markers expressed at different cellular stages of erythropoiesis using FACS. However, limited studies are available on the in-depth phenotypic characterization of progenitors from human adult hematopoietic stem and progenitor cells (HSPCs) to red blood cells. Therefore, using a set of designed marker panels, in the current study we have kinetically characterized the hematopoietic, erythroid progenitors, and terminally differentiated erythroblasts ex vivo. Furthermore, the progenitor stages were explored for expression of CD117, CD31, CD41a, CD133, and CD45, along with known key markers CD36, CD71, CD105, and GPA. Additionally, we used these marker panels to study the stage-specific phenotypic changes regulated by the epigenetic regulator; Nuclear receptor binding SET Domain protein 1 (NSD1) during erythropoiesis and to study ineffective erythropoiesis in myelodysplastic syndrome (MDS) and pure red cell aplasia (PRCA) patients. Our immunophenotyping strategy can be used to sort and study erythroid-primed hematopoietic and erythroid precursors at specified time points and to study diseases resulting from erythroid dyspoiesis. Overall, the current study explores the in-depth kinetics of phenotypic changes occurring during human erythropoiesis and applies this strategy to study normal and defective erythropoiesis. Full article