scholarly journals Beta Thalassemia Major: Overview of Molecular Etiology, Pathophysiology, Current and Novel Therapeutic Approaches

Author(s):  
S. El Kababi ◽  
B. El Khalfi ◽  
K. El Maani ◽  
A. Soukri

Major beta thalassemia is a severe form of thalassemia caused by the alteration of two beta globin genes resulting in a defective synthesis of hemoglobin. It is characterized by chronic severe anemia, ineffective erythropoiesis (IE) and iron overload. However although the thransfusion and chelation assosciated constitute the basis of the traitement curently recommended, they do not allow always to control the iron overload induced by pathology and repeated transfusions. Hematopoietic stem cell transplantation (HSCT) has proven to be a definitive treatment for beta thalassemia. However, this procedure is confronted to immunological complications and the small nomber of histocompatible donors. In the face of these therapeutic blocks, much research has been undertaken in recent years leading to the development of a number of promising therapeutic strategies in order to reduce the constraints linked to current chronic treatments, and to move towards an access to healing for all patients. Among other three approaches are envisaged and are in the experimental phase: Gene therapy to restore globin chain imbalance, Improve ineffective erythropoiesis and Improve iron dysregulation. In this article we give a view on the pathophysiology, clinical manifestations, genetic origin of beta-thalassaemia major. The second part presents the therapeutic arsenal currently used, and its limits leading to therapeutic impasse. The last part explores the scientific tracks that present a real therapeutic potential in β-Thalassemia.

2019 ◽  
Vol 20 (16) ◽  
pp. 1603-1623 ◽  
Author(s):  
Eman M. Hamed ◽  
Mohamed Hussein Meabed ◽  
Usama Farghaly Aly ◽  
Raghda R.S. Hussein

Beta-thalassemia is a genetic disorder characterized by the impaired synthesis of the betaglobin chain of adult hemoglobin. The disorder has a complex pathophysiology that affects multiple organ systems. The main complications of beta thalassemia are ineffective erythropoiesis, chronic hemolytic anemia and hemosiderosis-induced organ dysfunction. Regular blood transfusions are the main therapy for beta thalassemia major; however, this treatment can cause cardiac and hepatic hemosiderosis – the most common cause of death in these patients. This review focuses on unique future therapeutic interventions for thalassemia that reverse splenomegaly, reduce transfusion frequency, decrease iron toxicity in organs, and correct chronic anemia. The targeted effective protocols include hemoglobin fetal inducers, ineffective erythropoiesis correctors, antioxidants, vitamins, and natural products. Resveratrol is a new herbal therapeutic approach which serves as fetal Hb inducer in beta thalassemia. Hematopoietic stem cell transplantation (HSCT) is the only curative therapy for beta thalassemia major and is preferred over iron chelation and blood transfusion for ensuring long life in these patients. Meanwhile, several molecular therapies, such as ActRIIB/IgG1 Fc recombinant protein, have emerged to address complications of beta thalassemia or the adverse effects of current drugs. Regarding gene correction strategies, a phase III trial called HGB-207 (Northstar-2; NCT02906202) is evaluating the efficacy and safety of autologous cell transplantation with LentiGlobin. Advanced gene-editing approaches aim to cut DNA at a targeted site and convert HbF to HbA during infancy, such as the suppression of BCL11A (B cell lymphoma 11A), HPFH (hereditary persistence of fetal hemoglobin) and zinc-finger nucleases. Gene therapy is progressing rapidly, with multiple clinical trials being conducted in many countries and the promise of commercial products to be available in the near future.


2021 ◽  
Author(s):  
Yasir Sharif ◽  
Saba Irshad ◽  
Muhammad Hamza Tariq ◽  
Muhammad Nadeem Asghar

Abstract The reason of high mortality rate in the patients of beta-thalassemia major is iron overload because it leads to many secondary complications. Condition of iron overload is known as hemochromatosis (HC). HC causes distorted formation of HFE protein that disturbs the whole pathway of HAMP protein synthesis which results in unbounded form of ferroportin and hence iron keeps absorbing in the body, leading to iron accumulation. The current study was conducted to identify a potential phytochemical that could bind to ferroportin and inhibits its iron absorbing activity within the body. The 3D structure of Ferroportin was unavailable in protein data bank PDB, therefore, it was developed by using different bioinformatics tools and best structure was identified through SAVES and RAMPAGE analysis. This best structure was docked with a library of 1010 bioactive phytochemicals by using MOE-2009 software. The top-ten ranked potential inhibitors were then evaluated for drug-like properties through molsoft and Molinspiration server followed by ADMET analysis. Our study demonstrated that “Taxifolin’ showed the maximum binding affinity with Ferroportin and also demonstrates maximum drug-like properties. Thus this compound could be used as a potential inhibitor of ferroportin. However, in-vitro and in-vivo studies must be conducted to validate the therapeutic potential of taxifolin against hemochromatosis.


Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 959-959
Author(s):  
M Akif Yesilipek ◽  
Gulsun Karasu ◽  
Zuhre Kaya ◽  
Baris B Kuskonmaz ◽  
Vedat Uygun ◽  
...  

Abstract Introduction: Hematopoietic stem cell transplantation (HSCT) is being increasingly used as curative therapy for severe disorders of the hematopoietic system and transfusional iron overload (TIO) contributes considerably to treatment-related morbidity and mortality after HSCT. Management of iron overload in the post-HSCT setting may be complicated since the use of therapeutic phlebotomies is often not feasible due to ongoing anemia and compliance to deferoxamine is low. Studies that evaluate the safety dose of deferasirox (DFX), which is the most commonly used chelation therapy, in this setting are limited. Purpose & Methods: This is a prospective, phase 2, multicenter, single-arm study to evaluate the efficacy and safety of iron chelation with oral DFX in beta-thalassemia major (TM) patients who have undergone HSCT. The study was conducted in 7 centers from Turkey. The primary objective was to evaluate if DFX could provide clinically safe chelation in a target pool of 26 pediatric patients with TIO within a minimum of 6 months and maximum of 2 years after related/unrelated HSCT. Patients had to be transfusion-independent and have iron overload at screening defined by serum ferritin (SF) of >1000 μg/L or cardiac MRI T2* <20 ms or liver iron concentration (LIC, by MRI R2) of ≥5 mg/g. The study included male and female TM patients ≥2 to <18 years old who had undergone HSCT with a washout period from immunosuppressive therapy of at least 3 months. Patients received DFX at an initial dose of 10 mg/kg/day with up titration every 3 months by 5 mg/kg/day per investigator judgment to a maximum of 20 mg/kg/day. Therapy continued for 52 weeks or until SF reached below 500 μg/L. Aside from AE monitoring, assessments were undertaken at baseline and every 28 days (unless closer assessments were need for dose initiation and adjustment) and included complete blood counts, biochemistry and urinalysis, and SF. MRI assessment of liver (R2) and cardiac (T2*) iron were also conducted at baseline and 52 weeks. Results: Interim data from the first 18 of 26 patients (mean age 8.3 years, 66.7% males) who completed 12 months follow up are presented in this analysis. A total of 97 AEs were recorded in the 18 patients. The majority of AEs were of Grade I (n=57) or II (n=34) severity. Five (5.2%) were suspected to be related to study drug and 6 AEs (6.2%) were considered serious. Five (5.2%) AEs resulted in study drug temporary interruption or dose adjustment, 2 (2.1%) required hospitalization, 54 (55.7%) required concomitant medication, while 36 (37.1%) had no action taken. Three patients had dose decrease due to AEs. The dose was re-escalated up to 20 mg/kg/day after the AEs resolved. In total, 11 (61.1%) patients achieved 20 mg/kg/day. Only one patient dropped out due to progressive ALT increase. Median ALT level decreased from 26 IU/L (range: 10-117) at baseline to 18 IU/L (range: 9-101) at week 52. The median SCr was similar at baseline 0.4 mg/dL (range: 0.2-0.6) and week 52 0.4 mg/dL (range: 0.2-0.8). Median cystatin C was similar at baseline 0.7 mg/mL (range: 0.6-0.9) and week 52 0.7 mg/mL (range: 0.5-1.1) (Figure 1A-B). Five patients had proteinuria at baseline and increased proteinuria compared to previous visit by dipstick analysis was described in 7 (38.9%) patients, irrespective of DFX dose by 52 weeks. No patient with proteinuria required any dose adjustments by 52 weeks. SF significantly and consistently decreased throughout the 52 weeks from a median of 1752.3 μg/L (range: 873.7-2716) to 915.2 μg/L (range: 250.1-2740), p<0.001 (Figure 2). At week 52, 6 (33.3%) patients had reached SF <500 μg/L. LIC also significantly decreased from a median of 9.9 mg/g (range: 4.8-43) to 4.1 mg/g (range 0.9-8.5), p<0.001. Cardiac T2* increased from a median of 26.1 ms (range: 18.7-41) to 28.8 ms (18.5-44), p=0.605. Conclusions: Our preliminary results showed that DFX up to 20 mg/kg/day is safe and effective in reducing iron burden for TM patients following HSCT. This was evident through significant reductions of systemic, hepatic and cardiac iron overload. Final data from the completed study should confirm these findings and establish the role for DFX in this patient population. Figure 1. Figure 1. Figure 2. Figure 2. Figure 3. Figure 3. Disclosures Dag: Novartis: Employment. Birkent:Novartis: Employment.


Author(s):  
Galina Ovsyannikova ◽  
Dmitry Balashov ◽  
Irina Demina ◽  
Larisa Shelikhova ◽  
Alexey Pshonkin ◽  
...  

Background: Ineffective erythropoiesis (IE) is the most prominent feature of transfusion-dependent beta-thalassemia (TDT), which leads to extramedullary hemopoiesis. The rejection rate in allogeneic hematopoietic stem cell transplantation (HSCT) is clearly superior in heavily transfused patients (pts) with TDT accompanied by prominent IE. Therefore, a pre-transplantation treatment bridging to HSCT is often used to reduce allosensibilization and IE. Ruxolitinib (RUX) is a JAK-1/JAK-2-inhibitor and has showed its efficacy to suppress IE and the immune system. A previously published study on RUX in adult pts with TDT has revealed that this treatment significantly reduces spleen size and is well tolerated. Procedure: Ten pts (5-14 y.o.) with TDT and an enlarged spleen were enrolled. The dose of RUX was adjusted for age: for pts younger < 11 years: 40 - 100 mg/m2 and for pts >11 years: 20 - 30 mg/m2. HSCT was performed in 8 out of the 10 pts. Results: After the first 3 months of RUX therapy the spleen volume decreased in 9 out of the 10 cases by 9.1 – 67.5% (M = 35.4%) compared to the initial size (р = 0.003). The adverse events of RUX included infectious complications, moderate thrombocytopenia as well as headache and were successfully managed by reducing the dose. The outcomes of HSCT were favorable in 7 out of the 8 cases. Conclusion: RUX is promising as a short-term pre-HSCT treatment for pediatric pts with TDT and pronounced IE.


2015 ◽  
Vol 3 (2) ◽  
pp. 287-292 ◽  
Author(s):  
Khaled M. Salama ◽  
Ola M. Ibrahim ◽  
Ahmed M. Kaddah ◽  
Samia Boseila ◽  
Leila Abu Ismail ◽  
...  

BACKGROUND: Beta Thalassemia is the most common chronic hemolytic anemia in Egypt (85.1%) with an estimated carrier rate of 9-10.2%. Injury to the liver, whether acute or chronic, eventually results in an increase in serum concentrations of Alanine transaminase (ALT) and Aspartate transaminase (AST).AIM: Evaluating the potentiating effect of iron overload & viral hepatitis infection on the liver enzymes.PATIENTS AND METHODS: Eighty (80) thalassemia major patients were studied with respect to liver enzymes, ferritin, transferrin saturation, HBsAg, anti-HCV antibody and HCV-PCR for anti-HCV positive patients.RESULTS: Fifty % of the patients were anti-HCV positive and 55% of them were HCV-PCR positive. Patients with elevated ALT and AST levels had significantly higher mean serum ferritin than those with normal levels. Anti-HCV positive patients had higher mean serum ferritin, serum ALT, AST and GGT levels and higher age and duration of blood transfusion than the negative group. HCV-PCR positive patients had higher mean serum ferritin and serum ALT and also higher age and duration of blood transfusion than the negative group.CONCLUSION: Iron overload is a main leading cause of elevated liver enzymes, and presence of HCV infection is significantly related to the increased iron overload.


Blood ◽  
2008 ◽  
Vol 111 (1) ◽  
pp. 421-429 ◽  
Author(s):  
Marco Gabbianelli ◽  
Ornella Morsilli ◽  
Adriana Massa ◽  
Luca Pasquini ◽  
Paolo Cianciulli ◽  
...  

In human β-thalassemia, the imbalance between α- and non–α-globin chains causes ineffective erythropoiesis, hemolysis, and anemia: this condition is effectively treated by an enhanced level of fetal hemoglobin (HbF). In spite of extensive studies on pharmacologic induction of HbF synthesis, clinical trials based on HbF reactivation in β-thalassemia produced inconsistent results. Here, we investigated the in vitro response of β-thalassemic erythroid progenitors to kit ligand (KL) in terms of HbF reactivation, stimulation of effective erythropoiesis, and inhibition of apoptosis. In unilineage erythroid cultures of 20 patients with intermedia or major β-thalassemia, addition of KL, alone or combined with dexamethasone (Dex), remarkably stimulated cell proliferation (3-4 logs more than control cultures), while decreasing the percentage of apoptotic and dyserythropoietic cells (<5%). More important, in both thalassemic groups, addition of KL or KL plus Dex induced a marked increase of γ-globin synthesis, thus reaching HbF levels 3-fold higher than in con-trol cultures (eg, from 27% to 75% or 81%, respectively, in β-thalassemia major). These studies indicate that in β-thalassemia, KL, alone or combined with Dex, induces an expansion of effective erythropoiesis and the reactivation of γ-globin genes up to fetal levels and may hence be considered as a potential therapeutic agent for this disease.


Blood ◽  
2017 ◽  
Vol 130 (Suppl_1) ◽  
pp. SCI-16-SCI-16
Author(s):  
Mitchell J Weiss

Genetic forms of anemia caused by HBB gene mutations that impair beta globin production are extremely common worldwide. The resultant disorders, mainly sickle cell disease (SCD) and beta-thalassemia, cause substantial morbidity and early mortality. Treatments for these diseases include medical therapies and bone marrow transplantation (BMT), which can be curative. However, medical therapies are suboptimal and BMT is associated with serious toxicities, particularly because HLA-matched allogeneic sibling donors are not available for most patients. Thus, new therapies are urgently needed for millions of affected individuals. Gene therapy offers great promise to cure SCD and beta thalassemia and emerging genome editing technologies represent a new form of gene therapy. Approaches to cure SCD and beta-thalassemia via genome editing include: 1) Correction of HBB mutations by homology directed repair (HDR); 2) use of non-homologous end joining (NHEJ) to activate gamma globin production and raise fetal hemoglobin (HbF) levels; 3) NHEJ to disrupt alpha-globin genes (HBA1 or HBA2) and thereby alleviate globin chain imbalance in intermediately severe forms of beta thalassemia. Challenges for these approaches include selection of the most effective genome editing tools, optimizing their delivery to hematopoietic stem cells (HSCs), improving specificity and better understanding potential off target effects, particularly those that are biologically relevant. Technologies for genome editing are advancing rapidly and being tested in preclinical models for HBB-mutated disorders. Ultimately, however, the best strategies can only be identified in clinical trials. This will require close collaborations between basic/translational researchers who study genome editing, clinical hematologists and collaboration between experts in academia and the bio-pharmaceutical industry. Disclosures No relevant conflicts of interest to declare.


Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 2-2
Author(s):  
Annamaria Aprile ◽  
Laura Raggi ◽  
Mariangela Storto ◽  
Isabella Villa ◽  
Sarah Marktel ◽  
...  

In the last decade many studies unraveled the bone marrow (BM) niche regulation and crosstalk with hematopoietic stem cells (HSC) in steady state conditions and malignancies, but HSC-niche interactions are still underexplored in hematological inherited disorders. We have recently provided the first demonstration of impaired HSC function caused by an altered BM niche in a non-malignant disease, beta-thalassemia (BT) (Aprile et al., Blood 2020). BT is a congenital hemoglobin disorder resulting in severe anemia, ineffective erythropoiesis and multi-organ secondary complications, such as bone defects. It is one of the most globally widespread monogenic diseases, which can be cured by transplantation of HSC from compatible healthy donors or autologous HSC from patients upon gene therapy. Cases of graft failure have been reported, but causes have not been deeply investigated and might include an impaired HSC function and a defective supporting activity of the BM niche, worsened by age and disease progression. We showed that the prolonged residence of HSC into an altered BM stromal niche in BT Hbbth3/+ (th3) mice negatively affects stem cell number, quiescence and self-renewal. Moreover, we demonstrated that correction of HSC-stromal niche crosstalk rescues BT HSC function by in vivo reactivation of parathyroid hormone (PTH) signaling. Consistently with the common finding of osteoporosis in BT patients, we found reduced bone deposition and low levels of PTH also in the murine model. We investigated the potential mechanisms underlying the decreased PTH and bone defect and we focused on the role of fibroblast growth factor-23 (FGF-23). FGF-23 is a systemic hormone mainly secreted by osteocytes, which acts as negative regulator of bone metabolism by inhibiting bone mineralization and PTH production by parathyroid glands. Since FGF-23 is positively modulated by the anemia-related factor erythropoietin (EPO), we hypothesized that the high EPO levels in BT, subsequent to ineffective erythropoiesis, might contribute to increase FGF-23. We measured high levels of circulating FGF-23 in th3 mice (wt vs. th3: 399.7±69.77 vs. 1975±209.3 pg/ml, p&lt;0.01) and also in BT patients (HD vs. THAL: 94.2±3.8 vs. 125.8±9.2 RU/ml, p&lt;0.05). To provide proof of concept data of the causative role of FGF-23 on BT bone and stromal niche defects, we inhibited FGF-23 signaling. FGF-23 inhibition by in vivo administration of FGF-23 blocking peptide rescued the bone defect in th3 mice, by increasing trabecular bone mineral density (th3 vs. th3+FGF23inh: 117.7±3.3 vs. 181.1±6.9 mg/cm3, p&lt;0.0001). Importantly, the treatment restored the frequency of HSC to levels comparable to wild-type controls by expanding the pool of quiescent cells (th3 vs. th3+FGF23inh: 0.03±0.002 vs. 0.07±0.0% on Linneg BM cells, p&lt;0.0001). Consistently, we found increased the expression of key molecules by bone cells, such as Jagged-1 and osteopontin, involved in the functional crosstalk between HSC and the stromal niche. Interestingly, FGF-23 inhibition had also a positive anti-apoptotic effect on the expanded BM erythroid compartment, promoting the maturation of erythroid precursors, as already shown in models of secondary anemias. Preliminary evidence in BT patients showed negative correlations between FGF-23 levels and markers of bone homeostasis (e.g. osteocalcin and vitamin D) and positive correlations with makers of ineffective erythropoiesis (e.g. reticulocytes), thus proposing FGF-23 as the molecule at the crossroads of erythropoiesis and bone metabolism in BT. In vivo studies and molecular analysis in th3 mice and patients' samples will better unravel the causative role of EPO on FGF-23 levels in BT and the negative impact of high FGF-23 on bone mineralization and BM stromal niche-HSC interactions. Our findings uncover an underexplored role of FGF-23 in bone and BM niche defects in BT, as a condition of severe anemia and chronic EPO stimulation. The inhibition of FGF-23 signaling might provide a novel strategy to ameliorate bone compartment and restore HSC-BM niche interactions in BT, with a potential translational relevance in improving HSC transplantation approaches. Disclosures Motta: Sanofi Genzyme: Honoraria. Cappellini:BMS: Honoraria; CRISPR Therapeutics, Novartis, Vifor Pharma: Membership on an entity's Board of Directors or advisory committees; Genzyme/Sanofi: Honoraria, Membership on an entity's Board of Directors or advisory committees.


Author(s):  
Shaukat Ali ◽  
Shumaila Mumtaz ◽  
Hafiz Abdullah Shakir ◽  
Hafiz Muhammad Tahir ◽  
Tafail Akbar Mughal

Thalassemia is genetic blood disease cause by absence or decrease of one or more of the globin chain synthesis. Beta thalassemia is characterized by one or more mutations in beta globin gene. Absence or reduced amount the of beta globin chains cause ineffective erythropoiesis which leads to anemia. Beta thalassemia has been further divided into three main forms: Thalassemia minor/silent carrier, major and intermedia. More severe form is thalassemia major in which patients depend upon blood transfusion for survival and high level of iron occur as a consequence of consistent blood transfusion. Over loaded iron invokes the synthesis of reactive oxygen species that are toxic in redundancy and triggering the impairment to vascular, endocrine and hepatic system. Thalassemia can be diagnosed and detected through various laboratory tests such as blood smear, prenatal testing (genetic testing of amniotic fluid), DNA analysis (genetic testing) and complete blood count. Treatment of thalassemia intermedia is symptomatic but it can also be managed by splenectomy and folic supplementation. While thalassemia major can be treated by transplantation of bone marrow, regular transfusion of blood and iron chelation treatment, stimulation of fetal hemoglobin production, hematopoietic stem cell transplantation and gene therapy.


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