Iron toxicity - Its effect on the bone marrow.

Excess iron can be extremely toxic for the body and may cause organ damage in the absence of iron chelation therapy. Preclinical studies on the role of free iron on bone marrow function have shown that iron toxicity leads to the accumulation of reactive oxygen species, affects the expression of genes coding for proteins that regulate hematopoiesis, and disrupts hematopoiesis. These effects could be partially attenuated by iron-chelation treatment with deferasirox, suggesting iron toxicity may have a negative impact on the hematopoietic microenvironment. Iron toxicity is of concern in transfusion-dependent patients. Importantly, iron chelation with deferasirox can cause the loss of transfusion dependency and may induce hematological responses, although the mechanisms through which deferasirox exerts this action are currently unknown. This review will focus on the possible mechanisms of toxicity of free iron at the bone marrow level and in the bone marrow microenvironment.

Unraveling the mechanisms behind iron overload and ineffective hematopoiesis in myelodysplastic syndromes.

Myelodysplastic syndromes (MDS) are a group of clonally-acquired blood disorders characterized by ineffective hematopoiesis leading to cytopenias. Red blood cell transfusions are an important component of supportive care in patients with MDS. Prolonged exposure to transfusions can lead to iron overload, which results in iron-induced toxicity caused by the production of reactive oxygen species (ROS). ROS accumulation has detrimental effects also on hematopoietic stem cells and may contribute to MDS progression. The observation that iron chelation improves hematologic parameters and reduces transfusion dependence further indicates that iron overload impairs hematopoiesis. Over the past decade, the mechanisms regulating iron homeostasis and the complex interplay between iron overload and toxicity, ineffective hematopoiesis, and transformation to leukemia have become clearer. In this narrative review, we provide an overview of recent findings pertaining to iron overload in patients with MDS and its effects on hematopoiesis. We also briefly discuss the position of chelation therapy in the context of the new developments.

Hepatocellular carcinoma in thalassaemia: an update of the Italian Registry.

The risk of developing hepatocellular carcinoma (HCC) in patients with thalassaemia is increased by transfusion-transmitted infections and haemosiderosis. All Italian Thalassaemia Centres use an ad hoc form to report all diagnoses of HCC to the Italian Registry. Since our last report, in 2002, up to December 2012, 62 new cases were identified, 52% of whom were affected by thalassaemia major (TM) and 45% by thalassaemia intermedia (TI). Two had sickle-thalassaemia (ST). The incidence of the tumour is increasing, possibly because of the longer survival of patients and consequent longer exposure to the noxious effects of the hepatotropic viruses and iron. Three patients were hepatitis B surface antigen-positive, 36 patients showed evidence of past infection with hepatitis B virus (HBV). Fifty-four patients had antibodies against hepatitis C virus (HCV), 43 of whom were HCV RNA positive. Only 4 had no evidence of exposure either to HCV or HBV. The mean liver iron concentration was 8 mg/g dry weight. Therapy included chemoembolization, thermoablation with radiofrequency and surgical excision. Three patients underwent liver transplant, 21 received palliative therapy. As of December 2012, 41 patients had died. The average survival time from HCC detection to death was 11·5 months (1·4-107·2 months). Ultrasonography is recommended every 6 months to enable early diagnosis of HCC, which is crucial to decrease mortality.

Antibodies reacting with Simian virus 40 mimotopes in serum samples from patients with thalassaemia major.

BACKGROUND: Simian virus 40 (SV40) is a small DNA tumour virus. Footprints of the virus have been detected in different humam lymphoproliferative disorders and in blood specimens of blood from healthy blood donors. This study was carried out to verify whether SV40 antibodies can be detected in serum samples from multiply transfused patients with thalassaemia major. MATERIALS AND METHODS: An indirect enzyme-linked immunosorbent assay was employed, using SV40 specific synthetic peptides mimicking the antigens of the viral capsid proteins 1-2-3, to test for the presence of antibodies to SV40 in serum samples taken from patients affected by transfusion-dependent thalassaemia major (n=190) and healthy blood donors (n=251). RESULTS: The prevalence of antibodies against SV40 was higher in patients than in controls (24% vs 17%). The prevalence increased and was significantly higher in the older age group of patients affected by thalassemia major than in controls (38% vs 20%, p<0.04). DISCUSSION: The higher prevalence of serum antibodies against simian virus 40 in older, multiply transfused patients with thalassamia major than in controls suggests that this virus, or a closely related yet unknown human polyomavirus, could have been transmitted in the past by transfusion with whole blood. At the same time, our data indicate no significant differences in prevalence of SV40 antibodies in patients and controls of younger age thus suggesting that current transfusion methods with leucodepletion and filtered red cells are safe.

Dark blood versus bright blood T2 acquisition in cardiovascular magnetic resonance (CMR) for thalassaemia major (TM) patients: evaluation of feasibility, reproducibility and image quality.

OBJECTIVES: To compare the effectiveness of dark blood (DB) versus bright blood (BB) sequences. To assess the intra and inter-observer variability and inter-study reproducibility between BB versus DB. To evaluate image quality level in the two sequences. METHODS: In a setting of 138 patients we performed CMR using cardiac gated Gradient-multiecho single breath-hold BB and DB sequences in the middle ventricular septum. Each acquisition was repeated during the same exam. Truncation method was used to account for background noise. Image quality (IQ) was assessed using a 5 point grading scale and image analysis was conducted by 2 experienced observers. RESULTS: Compared with the conventional BB acquisition, the coefficient of correlation and significance of the DB technique was superior for intra-observer reproducibility (p<0.001), inter-observer reproducibility (p<0.001) and inter-study reproducibility (p<0.001). The variability is also lower for DB sequences for T2* values <14 ms. Assessment of artifacts showed a superior score for DB versus BB scans (4 versus 3, p<0.001). CONCLUSIONS: Improvement in terms of inter observer and inter study variability using DB sequences was obtained. The greatest disparity between them was seen in inter-study reproducibility and higher IQ in DB was seen. Study demonstrates better performance of DB imaging compared to BB in presence of comparable effectiveness.

Ectopic calcification in ß-thalassemia patients is associated with increased oxidative stress and lower MGP carboxylation.

A number of beta-thalassemia (ß-thal) patients in the course of the disease exhibit ectopic calcification affecting skin, eyes and the cardiovascular system. Clinical and histopathological features have been described similar to those in pseudoxanthoma elasticum (PXE), although different genes are affected in the two diseases. Cultured dermal fibroblasts from ß-thal patients with and without PXE-like clinical manifestations have been compared for parameters of redox balance and for the expression of proteins, which have been already associated with the pathologic mineralisation of soft connective tissues. Even though oxidative stress is a well-known condition of ß-thal patients, our results indicate that the occurrence of mineralized elastin is associated with a more pronounced redox disequilibrium, as demonstrated by the intracellular increase of anion superoxide and of oxidized proteins and lipids. Moreover, fibroblasts from ß-thal PXE-like patients are characterized by decreased availability of carboxylated matrix Gla protein (MGP), as well as by altered expression of proteins involved in the vitamin K-dependent carboxylation process. Results demonstrate that elastic fibre calcification is promoted when redox balance threshold levels are exceeded and the vitamin K-dependent carboxylation process is affected decreasing the activity of MGP, a well-known inhibitor of ectopic calcification. Furthermore, independently from the primary gene defect, these pathways are similarly involved in fibroblasts from PXE and from ß-thal PXE-like patients as well as in other diseases leading to ectopic calcification, thus suggesting that can be used as markers of pathologic mineralisation.

Long-term treatment with deferiprone enhances left ventricular ejection function when compared to deferoxamine in patients with thalassemia major.

Transfusion and iron chelation treatment have significantly reduced morbidity and improved survival of patients with thalassemia major. However, cardiac disease continues to be the most common cause of death. We report the left-ventricular ejection fraction, determined by echocardiography, in one hundred sixty-eight patients with thalassemia major followed for at least 5years who received continuous monotherapy with deferoxamine (N=108) or deferiprone (N=60). The statistical analysis, using the generalized estimating equations model, indicated that the group treated with deferiprone had a significantly better left-ventricular ejection fraction than did those treated with deferoxamine (coefficient 0.97; 95% CI 0.37; 1.6, p=0.002). The heart may be particularly sensitive to iron-induced mitochondrial damage because of the large number of mitochondria and its low level of antioxidants. Deferiprone, because of its lower molecular weight, might cross into heart mitochondria more efficiently, improving their activity and, thereby, myocardial cell function. Our findings indicate that the long-term administration of deferiprone significantly enhances left-ventricular function over time in comparison with deferoxamine treatment. However, because of limitations related to the design of this study, these findings should be confirmed in a prospective, randomized clinical trial.

Relationship between myocardial T2 values and cardiac volumetric and functional parameters in ß-thalassemia patients evaluated by cardiac magnetic resonance in association with serum ferritin levels.

PURPOSE: Myocardial T2 cardiovascular magnetic resonance provides a rapid and reproducible assessment of cardiac iron load in thalassemia patients. Although cardiac involvement is mainly characterized by left ventricular dysfunction caused by iron overload, little is known about right ventricular function. The aim of this study was to assess the relationship between T2 value in myocardium and left-right ventricular volumetric and functional parameters and to evaluate the existing associations between left-right ventricles volumetric and functional parameter, myocardial T2 values and blood ferritin levels. MATERIALS AND METHODS: A retrospective analysis of 208 patients with ß-thalassemia major and thalassemia intermedia was performed (109 males and 99 females; mean age 37.7 ± 13 years; 143 thalassemia major, 65 thalassemia intermedia). Myocardial iron load was assessed by T2 measurements, and volumetric functions were analyzed using the steady state free precession sequence. RESULTS: A significant correlation was observed between EFLV and T2 (p=0.0001), EFRV and T2 (p=0.0279). An inverse correlation was present between DVLV and T2 (p=0.0468), SVLV and T2 (p=0.0003), SVRV and T2 (p=0.0001). There was no significant correlation between cardiac T2 and LV-RV mass indices. A significant correlation was observed between T2 and serum ferritin levels (p<0.001) and between EFLV and serum ferritin (p<0.05). CONCLUSION: Myocardial iron load assessed by T2 cardiac magnetic resonance is associated with deterioration in left-right ventricular function; this is more evident when T2 values fall below 14 ms. CMR appears to be a promising approach for cardiac risk evaluation in TM patients.

MicroRNA-486-3p regulates γ-globin expression in human erythroid cells by directly modulating BCL11A.

MicroRNAs (miRNAs) play key roles in modulating a variety of cellular processes through repression of mRNAs target. The functional relevance of microRNAs has been proven in normal and malignant hematopoiesis. While analyzing miRNAs expression profile in unilineage serum-free liquid suspension unilineage cultures of peripheral blood CD34(+) hematopoietic progenitor cells (HPCs) through the erythroid, megakaryocytic, granulocytic and monocytic pathways, we identified miR-486-3p as mainly expressed within the erythroid lineage. We showed that miR-486-3p regulates BCL11A expression by binding to the extra-long isoform of BCL11A 3'UTR. Overexpression of miR-486-3p in erythroid cells resulted in reduced BCL11A protein levels, associated to increased expression of γ-globin gene, whereas inhibition of physiological miR-486-3p levels increased BCL11A and, consequently, reduced γ-globin expression. Thus, miR-486-3p regulating BCL11A expression might contributes to fetal hemoglobin (HbF) modulation and arise the question as to what extent this miRNA might contribute to different HbF levels observed among ß-thalassemia patients. Erythroid cells, differentiated from PB CD34(+) cells of a small cohort of patients affected by major or intermedia ß-thalassemia, showed miR-486-3p levels significantly higher than those observed in normal counterpart. Importantly, in these patients, miR-486-3p expression correlates with increased HbF synthesis. Thus, our data indicate that miR-486-3p might contribute to different HbF levels observed among thalassemic patients and, possibly, to the clinical severity of the disease.

Fibroblast involvement in soft connective tissue calcification.

Soft connective tissue calcification is not a passive process, but the consequence of metabolic changes of local mesenchymal cells that, depending on both genetic and environmental factors, alter the balance between pro- and anti-calcifying pathways. While the role of smooth muscle cells and pericytes in ectopic calcifications has been widely investigated, the involvement of fibroblasts is still elusive. Fibroblasts isolated from the dermis of pseudoxanthoma elasticum (PXE) patients and of patients exhibiting PXE-like clinical and histopathological findings offer an attractive model to investigate the mechanisms leading to the precipitation of mineral deposits within elastic fibers and to explore the influence of the genetic background and of the extracellular environment on fibroblast-associated calcifications, thus improving the knowledge on the role of mesenchymal cells on pathologic mineralization.

Cardiac and hepatic iron and ejection fraction in thalassemia major: multicentre prospective comparison of combined deferiprone and deferoxamine therapy against deferiprone or deferoxamine monotherapy.

BACKGROUND: Due to the limited data available in literature, the aim of this multi-centre study was to prospectively compare in thalassemia major (TM) patients the efficacy of combined deferiprone (DFP) and deferoxamine (DFO) regimen versus either DFP and DFO in monotherapy by cardiovascular magnetic resonance (CMR) over a follow up of 18 months. METHODS: Among the first 1135 TM patients in the MIOT (Myocardial Iron Overload in Thalassemia) network, we evaluated those who had received either combined regimen (DFO + DFP, N=51) or DFP (N=39) and DFO (N=74) monotherapies between the two CMR scans. Iron overload was measured by T2* multiecho technique. Biventricular function parameters were quantitatively evaluated by cine images. RESULTS: The percentage of patients that maintained a normal global heart T2* value was comparable between DFP+DFO versus both monotherapy groups. Among the patients with myocardial iron overload at baseline, the changes in the global heart T2* and in biventricular function were not significantly different in DFP+DFO compared with the DFP group. The improvement in the global heart T2* was significantly higher in the DFP+DFO than the DFO group, without a difference in biventricular function. Among the patients with hepatic iron at baseline, the decrease in liver iron concentration values was significantly higher with combination therapy than with either monotherapy group. CONCLUSIONS: In TM patients at the dosages used in the real world, the combined DFP+DFO regimen was more effective in removing cardiac iron than DFO, and was superior in clearing hepatic iron than either DFO or DFP monotherapy. Combined therapy did not show an additional effect on heart function over DFP.

Serial echocardiographic left ventricular ejection fraction measurements: a tool for detecting thalassemia major patients at risk of cardiac death.

Cardiac damage remains a major cause of mortality among patients with thalassemia major. The detection of a lower cardiac magnetic resonance T2* (CMR-T2*) signal has been suggested as a powerful predictor of the subsequent development of heart failure. However, the lack of worldwide availability of CMR-T2* facilities prevents its widespread use for follow-up evaluations of cardiac function in thalassemia major patients, warranting the need to assess the utility of other possible procedures. In this setting, the determination of left ventricular ejection fraction (LVEF) offers an accurate and reproducible method for heart function evaluation. These findings suggest a reduction in LVEF≥7%, over time, determined by 2-D echocardiography, may be considered a strong predictive tool for the detection of thalassemia major patients with increased risk of cardiac death. The reduction of LVEF≥7% had higher (84.76%) predictive value. Finally, Kaplan-Meier survival curves of thalassemia major patients with LVEF≥7% showed a statistically significant decreased probability of survival for heart disease (p=0.0022). However, because of limitations related to the study design, such findings should be confirmed in a large long-term prospective clinical trial.

Long-term use of deferiprone significantly enhances left-ventricular ejection function in thalassemia major patients.

A multicenter randomized open-label long-term sequential deferiprone­deferoxamine (DFP-DFO) versus DFP alone trial (sequential DFP-DFO) performed in patients with thalassemia major (TM) was retrospectively reanalyzed to assess the variation in the left ventricular ejection fraction (LVEF) [1].

Iron chelation therapy in thalassemia major: a systematic review with meta-analyses of 1520 patients included on randomized clinical trials.

The effectiveness of deferoxamine (DFO), deferiprone (DFP), or deferasirox (DFX) in thalassemia major was assessed. Outcomes were reported as means±SD, mean differences with 95% CI, or standardized mean differences. Statistical heterogeneity was tested using χ2 (Q) and I2. Sources of bias and Grading of Recommendations Assessment, Development and Evaluation system (GRADE) were considered. Overall, 1520 patients were included. Only 7.4% of trials were free of bias. Overall measurements suggest low trial quality (GRADE). The meta-analysis suggests lower final liver iron concentrations during associated versus monotherapy treatment (p<0.0001), increases in serum ferritin levels during DFX 5, 10, and 20 mg/kg versus DFO-treated groups (p<0.00001, p<0.00001, and p=0.002, respectively), but no statistically significant difference during DFX 30 mg/kg versus DFO (p=0.70), no statistically significant variations in heart T2* signal during associated or sequential versus mono-therapy treatment (p=0.46 and p=0.14, respectively), increases in urinary iron excretion during associated or sequential versus monotherapy treatment (p=0.008 and p=0.02, respectively), and improved ejection fraction during associated or sequential versus monotherapy treatment (p=0.01 and p<0.00001, respectively). These findings do not support any specific chelation treatment. The literature shows risks of bias, and additional larger and longer trials are needed.

The management of iron chelation therapy: preliminary data from a national registry of thalassaemic patients.

Thalassaemia and other haemoglobinopathies constitute an important health problem in Mediterranean countries, placing a tremendous emotional, psychological, and economic burden on their National Health systems. The development of new chelators in the most recent years had a major impact on the treatment of thalassaemia and on the quality of life of thalassaemic patients. A new initiative was promoted by the Italian Ministry of Health, establishing a Registry for thalassaemic patients to serve as a tool for the development of cost-effective diagnostic and therapeutic approaches and for the definition of guidelines supporting the most appropriate management of the iron-chelating therapy and a correct use of the available iron-chelating agents. This study represents the analysis of the preliminary data collected for the evaluation of current status of the iron chelation practice in the Italian thalassaemic population and describes how therapeutic interventions can widely differ in the different patients' age groups.

Malignancies in ß-thalassemia patients: first description of two cases of thyroid cancer and review of the literature.

ß-Thalassemias are a group of hereditary blood disorders characterized by abnormalities in the synthesis of the ß hemoglobin (Hb) chains. This disease causes excessive storage of iron in all organs and endocrine glands. Treatment of ß-thalassemia major (ß-TM) consists of regular blood transfusions, iron chelation and management of secondary complications of iron overload. Endocrine abnormalities are frequently observed. In the last 25 years, the clinical picture of the disease has changed progressively thanks to improvement of treatments. Today, the majority of thalassemic patients reach adult age. The better prognosis and the longer lifespan of affected patients could be responsible for the susceptibility to other concomitant diseases which can manifest during their life. In this context, the possibility and recent literature reports about some cases of malignancy in thalassemic patients open new scenarios for oncoming years. We describe first reports of endocrine malignancies in thalassemic patients.

Sequential alternating deferiprone and deferoxamine treatment compared to deferiprone monotherapy: main findings and clinical follow-up of a large multicenter randomized clinical trial in -thalassemia major patients.

In ß-thalassemia major (ß-TM) patients, iron chelation therapy is mandatory to reduce iron overload secondary to transfusions. Recommended first line treatment is deferoxamine (DFO) from the age of 2 and second line treatment after the age of 6 is deferiprone (L1). A multicenter randomized open-label trial was designed to assess the effectiveness of long-term alternating sequential L1-DFO vs. L1 alone iron chelation therapy in ß-TM patients. Deferiprone 75 mg/kg 4 days/week and DFO 50 mg/kg/day for 3 days/week was compared with L1 alone 75 mg/kg 7 days/week during a 5-year follow-up. A total of 213 thalassemia patients were randomized and underwent intention-to-treat analysis. Statistically, a decrease of serum ferritin level was significantly higher in alternating sequential L1-DFO patients compared with L1 alone patients (p = 0.005). Kaplan-Meier survival analysis for the two chelation treatments did not show statistically significant differences (log-rank test, p = 0.3145). Adverse events and costs were comparable between the groups. Alternating sequential L1-DFO treatment decreased serum ferritin concentration during a 5-year treatment by comparison to L1 alone, without significant differences of survival, adverse events or costs. These findings were confirmed in a further 21-month follow-up. These data suggest that alternating sequential L1-DFO treatment may be useful for some ß-TM patients who may not be able to receive other forms of chelation treatment.

Deferasirox, deferiprone and desferrioxamine treatment in thalassemia major patients: cardiac iron and function comparison determined by quantitative magnetic resonance imaging.

BACKGROUND: Oral deferiprone was suggested to be more effective than subcutaneous desferrioxamine for removing heart iron. Oral once-daily chelator deferasirox has recently been made commercially available but its long-term efficacy on cardiac iron and function has not yet been established. Our study aimed to compare the effectiveness of deferasirox, deferiprone and desferrioxamine on myocardial and liver iron concentrations and bi-ventricular function in thalassemia major patients by means of quantitative magnetic resonance imaging. DESIGN AND METHODS: From the first 550 thalassemia subjects enrolled in the Myocardial Iron Overload in Thalassemia network, we retrospectively selected thalassemia major patients who had been receiving one chelator alone for longer than one year. We identified three groups of patients: 24 treated with deferasirox, 42 treated with deferiprone and 89 treated with desferrioxamine. Myocardial iron concentrations were measured by T2* multislice multiecho technique. Biventricular function parameters were quantitatively evaluated by cine images. Liver iron concentrations were measured by T2* multiecho technique. RESULTS: The global heart T2* value was significantly higher in the deferiprone (34 ± 11 ms) than in the deferasirox (21 ± 12 ms) and the desferrioxamine groups (27 ± 11 ms) (P = 0.0001). We found higher left ventricular ejection fractions in the deferiprone and the desferrioxamine versus the deferasirox group (P = 0.010). Liver iron concentration, measured as T2* signal, was significantly lower in the desferrioxamine versus the deferiprone and the deferasirox group (P = 0.004). CONCLUSIONS: The cohort of patients treated with oral deferiprone showed less myocardial iron burden and better global systolic ventricular function compared to the patients treated with oral deferasirox or subcutaneous desferrioxamine.

Renal complications in transfusion-dependent beta thalassaemia.

Increased survival in patients with ß thalassaemia major (TM) allowed for several morbidities to manifest. Renal manifestations of the disease and its treatment have been poorly evaluated. There is evidence, mainly from studies in the paediatric population, of tubular dysfunction and glomerular filtration rate abnormalities in this patient population. Long-term outcomes of these changes, however, have not been prospectively investigated. The pathogenesis of these abnormalities could be attributed to iron overload, too aggressive iron removal, and/or the underlying anaemia. These changes seem to be nonprogressive, resolve spontaneously in most part, or may require iron chelator dose modifications. Relative iron depletion may explain renal function changes attributed to chelation therapy; thus, sudden removal of iron or overchelation should be avoided. Future studies should aim to evaluate the natural history of kidney function in TM patients to help understand the mechanisms and long-term sequelae of the observed renal changes.

Increased survival and reversion of iron-induced cardiac disease in patients with thalassemia major receiving intensive combined chelation therapy as compared to desferoxamine alone.

Myocardial iron overload is the leading cause of death in patients with beta-thalassemia major. An intensification monotherapy with deferoxamine (DFO) as well as a combination therapy with DFO and deferiprone (DFP) reduces myocardial iron and improves cardiac function. However, the prognosis for thalassemia major patients with established cardiac disease switched from DFO monotherapy to combined DFP/DFO chelation is unknown. Twenty-eight thalassemia major patients with cardiac disease were enrolled in a prospective study lasting 42+/-6 months. Fifteen (9 high-ferritin and 6 low-ferritin) were placed on DFP/DFO (DFP, 75 mg/kg t.i.d.; DFO, 40-50mg/kg over 8-12h at night 5-7 days/week), while 13 (5 high- and 8 low-ferritin) received DFO alone. No cardiac events were observed among high-ferritin patients on combination therapy, whereas 4 cardiac events (p=0.0049), including three deaths, occurred in high-ferritin patients on DFO monotherapy. These findings demonstrate that in thalassemia major patients with well-established cardiac disease combined iron-chelation therapy with DFP/DFO is superior to DFO monotherapy.