Randomized controlled trials of iron chelators for the treatment of cardiac siderosis in thalassaemia major

CHMMOTv1 - cardiac and hepatic multi-echo (T2*) MRI images and clinical dataset for Iron overload on thalassemia patients

INTRODUCTION

Regarding deep learning networks in medical sciences for improving diagnosis and treatment purposes and the existence of minimal resources for them, we decided to provide a set of magnetic resonance images of the cardiac and hepatic organs.

DATABASE DESCRIPTION

The dataset included 124 patients (67 women and 57 men) with thalassemia (THM), the age range of (5-52) years. Patients were divided into two groups: with follow-up (1-5 times) at time intervals of about (5-6) months and without follow-up. T2* and, R2* values, the results of the Cardiac and Hepatic overload report (normal, mild, moderate, severe), and laboratory tests including Ferritin, Bilirubin (D, and T), AST, ALT, and ALP levels were provided as an Excel file. Also, the details of the patients' Echocardiogram data have been made available. This dataset CHMMOTv1) has been published in Mendeley Dataverse and also is accessible through the web at: http://databiox.com .

Ebselen: A promising therapy protecting cardiomyocytes from excess iron in iron-overloaded thalassemia patients

Iron-overload-associated cardiomyopathy has been one of the primary causes of mortality in thalassemia patients with iron burden. There is growing evidence citing the beneficial effects of ebselen as an antioxidant selectively blocking the divalent metal transporter 1 (DMT-1) to deter iron ingress into cardiomyocytes, raising internets in viewing this component in this population in order to treat and even prevent cardiomyopathy occurring from iron surplus. In this article, we reviewed the potential advantageous effects of ebselen in thalassemia patients who suffer from iron excess, susceptible to cardiomyopathy induced by iron overload. A systematic search in several databases, including PubMed, Scopus, and Web of Science, was conducted to explore the role of ebselen in controlling iron-overload-related cardiomyopathy in thalassemia patients by the keywords of Ebselen AND iron. The inclusion criteria were English-written preclinical and clinical studies investigating the efficacy and side effects of ebselen in an iron-overload context. After searching the databases, 44 articles were found. Next, of 19 published articles, 3 were included in this article. After reviewing the references of the included studies, no articles were added. In conclusion ebselen can be a promising adjuvant therapy in patients with thalassemia alongside the standard treatment with iron chelators, particularly in severe cases with cardiomyopathy, due to falling iron inflow by inhibiting DMT-1 and increasing ferroportin-1 expression and antioxidant properties. However, clinical studies need to be carried out to reach a definite conclusion.

Cardiovascular Magnetic Resonance Parametric Mapping Techniques: Clinical Applications and Limitations

PURPOSE OF REVIEW

Parametric mapping represents a significant innovation in cardiovascular magnetic resonance (CMR) tissue characterisation, allowing the quantification of myocardial changes based on changes on T1, T2 and T2* relaxation times and extracellular volume (ECV). Its clinical use is rapidly expanding, but it requires availability of dedicated equipment as well as expertise in image acquisition and analysis. This review focuses on the principles of CMR parametric mapping, its current clinical applications, important limitations, as well as future directions of this technique in cardiovascular medicine.

RECENT FINDINGS

There is increasing evidence that CMR parametric mapping techniques provide accurate diagnostic and prognostic tools that can be applied to and support the clinical management of patients with a range of cardiovascular disease. The unique capability of CMR myocardial tissue characterisation in cardiovascular diseases has further expanded by the introduction of parametric mapping. Its use in clinical practice presents opportunities but has also limitations.

Effects of mine waste water on rat: bioaccumulation and histopathological evaluation

The highlighting of the bioaccumulation capacity of metals in the internal organs, the mode of distribution at the level of internal organs, the interactions between them, respectively, and the histological changes occurred at the level of the liver and kidneys are the main aspects addressed in the present study. The experiment was performed on 4 groups of Wistar rats: 3 groups which were administered water from rivers located in the vicinity of the Bor mining operation and 1 control group. The determination of the metal content in the administered water samples and in the internal organs was performed using the flame atomic absorption spectrophotometer. Tissue alterations were assessed by histological technique and hematoxylin-eosin staining. The metal retention capacity in the internal organs differs depending on the metal concentration in the administered water sample but also on the organ in which the determination was made. Also, correlations were established between the concentrations of metals at the level of the organs, showing (a) positive and significant correlations-at the level of the heart between Zn and Cu, Fe, and Mn and at the level of the lungs between Mn and Cd-but the most numerous were reported in the testicle; (b) moderate correlations at liver level between Fe and Zn, at spleen level between Cu and Mn and Cd and at the level of the kidneys between Pb and Zn, Cu, and Fe; (c) negative correlations at renal level between Pb and Mn; and (d) insignificant correlations between Pb and Fe. The histological changes identified at the level of the liver and kidney become more obvious, and their aggravation is registered with the increase of the metal content.

Pituitary Iron Deposition and Endocrine Complications in Patients with β-Thalassemia: From Childhood to Adulthood

The endocrinological complications are a great concern in transfusion-dependent β-thalassemia (β-thal) patients. The pituitary iron deposition is regarded as the main cause of hormonal changes in thalassemic patients. In this study, our aim was to explore the association between endocrinological complications and pituitary iron overload by magnetic resonance imaging (MRI). Fifty transfusion-dependent thalassemia (TDT) patients were recruited for the study. Pituitary MRIs of patients were taken using a 1.5 Tesla Philips MRI machine. There was at least one clinical endocrine complication in two of three patients. The iron accumulation was moderate in the liver (60.0%) and was mild in hypophysis (16.0%) and in heart (8.0%). The hypogonadism and diabetes mellitus (DM) were not seen with a significantly increased pituitary iron burden. The hypogonadism was related to cardiac iron deposition (p = 0.04). The short stature was associated with a hepatic iron overload (p = 0.05). The conventional follow-up of patients with TDT might be inadequate and screening of patients with MRI of hypophysis along with heart and liver leads to better results.

Early detection of ventricular dysfunction by tissue Doppler echocardiography related to cardiac iron overload in patients with thalassemia

Cardiac T2* MRI is used as a gold standard for cardiac iron quantification in patients with transfusion-dependent thalassemia (TDT). We hypothesized that left ventricular (LV) diastolic dysfunction would reflect the severity of iron overload and can serve as an early detection of cardiac iron deposits. A study was conducted on all patients with TDT. Hemoglobin, serum ferritin and non-transferrin bound iron, together with a complete echocardiography and cardiac T2* MRI, were performed on all patients. Seventy-seven patients with TDT were enrolled (median age 14 years). In the patient group with a mean serum ferritin of > 2500 ng/mL during the past 12 months, there were more patients with severe cardiac iron deposits than in the group with a mean serum ferritin of ≤ 2500 ng/mL. Diastolic dysfunction was absent in all patients with a serum ferritin of < 1000 ng/mL. All patients with cardiac T2* ≤ 20 ms had grade III LV diastolic dysfunction. However, twenty-one percent of patients with cardiac T2* > 20 ms had LV diastolic dysfunction. The differences observed in pulmonary vein atrial reversal duration and mitral A-wave (PVAR-MVA) duration ≥ - 1 ms and an E/E' ratio ≥ 11 were proven to be the associated factors with the cardiac T2* ≤ 20 ms. Increased PVAR-MVA duration and increased E/E' ratio reliably reflected a severe iron overload, according to a cardiac T2* in patients with TDT. LV diastolic dysfunction can occur prior to severe cardiac iron deposition. Tissue Doppler echocardiography has the potential for the early detection of cardiac involvement in patients with TDT .

Iron and Chelation in Biochemistry and Medicine: New Approaches to Controlling Iron Metabolism and Treating Related Diseases

Iron is essential for all living organisms. Many iron-containing proteins and metabolic pathways play a key role in almost all cellular and physiological functions. The diversity of the activity and function of iron and its associated pathologies is based on bond formation with adjacent ligands and the overall structure of the iron complex in proteins or with other biomolecules. The control of the metabolic pathways of iron absorption, utilization, recycling and excretion by iron-containing proteins ensures normal biologic and physiological activity. Abnormalities in iron-containing proteins, iron metabolic pathways and also other associated processes can lead to an array of diseases. These include iron deficiency, which affects more than a quarter of the world's population; hemoglobinopathies, which are the most common of the genetic disorders and idiopathic hemochromatosis. Iron is the most common catalyst of free radical production and oxidative stress which are implicated in tissue damage in most pathologic conditions, cancer initiation and progression, neurodegeneration and many other diseases. The interaction of iron and iron-containing proteins with dietary and xenobiotic molecules, including drugs, may affect iron metabolic and disease processes. Deferiprone, deferoxamine, deferasirox and other chelating drugs can offer therapeutic solutions for most diseases associated with iron metabolism including iron overload and deficiency, neurodegeneration and cancer, the detoxification of xenobiotic metals and most diseases associated with free radical pathology.

Influence of mitochondrial and systemic iron levels in heart failure pathology

Iron deficiency or overload poses an increasingly complex issue in cardiovascular disease, especially heart failure. The potential benefits and side effects of iron supplementation are still a matter of concern, even though current guidelines suggest therapeutic management of iron deficiency. In this review, we sought to examine the iron metabolism and to identify the rationale behind iron supplementation and iron chelation. Cardiovascular disease is increasingly linked with iron dysmetabolism, with an increased proportion of heart failure patients being affected by decreased plasma iron levels and in turn, by the decreased quality of life. Multiple studies have concluded on a benefit of iron administration, even if just for symptomatic relief. However, new studies field evidence for negative effects of dysregulated non-bound iron and its reactive oxygen species production, with concern to heart diseases. The molecular targets of iron usage, such as the mitochondria, are prone to deleterious effects of the polyvalent metal, added by the scarcely described processes of iron elimination. Iron supplementation and iron chelation show promise of therapeutic benefit in heart failure, with the extent and mechanisms of both prospects not being entirely understood. It may be that a state of decreased systemic and increased mitochondrial iron levels proves to be a useful frame for future advancements in understanding the interconnection of heart failure and iron metabolism.

Direct measurements of ferric reductase activity of human 101F6 and its enhancement upon reconstitution into phospholipid bilayer nanodisc

We studied human 101F6 protein to clarify its physiological function as a ferric reductase and its relationship to tumor suppression activity. We found for the first time that purified 101F6 both in detergent micelle state and in phospholipid bilayer nanodisc state has an authentic ferric reductase activity by single turnover kinetic analyses. The kinetic analysis on the ferrous heme oxidation of reduced 101F6 upon the addition of a ferric substrate, ferric ammonium citrate (FAC), showed concentration-dependent accelerations of its reaction with reasonable values of K_M and V_max. We further verified the authenticity of the ferric reductase activity of 101F6 using nitroso-PSAP as a Fe²⁺-specific colorimetric chelator. 101F6 in nanodisc state showed higher efficiency for FAC than in detergent micelle state.

•

Human tumor suppressor 101F6 protein was reconstituted into nanodisc.

•

101F6 functions as a ferric reductase both in detergent micelle and in nanodisc.

•

101F6 in nanodisc showed higher efficiency in the reductase activity.

Quantitative cardiac MRI

Cardiac MRI has become an indispensable imaging modality in the investigation of patients with suspected heart disease. It has emerged as the gold standard test for cardiac function, volumes, and mass and allows noninvasive tissue characterization and the assessment of myocardial perfusion. Quantitative MRI already has a key role in the development and incorporation of machine learning in clinical imaging, potentially offering major improvements in both workflow efficiency and diagnostic accuracy. As the clinical applications of a wide range of quantitative cardiac MRI techniques are being explored and validated, we are expanding our capabilities for earlier detection, monitoring, and risk stratification of disease, potentially guiding personalized management decisions in various cardiac disease models. In this article we review established and emerging quantitative techniques, their clinical applications, highlight novel advances, and appraise their clinical diagnostic potential. Level of Evidence: 2 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2020;51:693-711.

Structural basis for promotion of duodenal iron absorption by enteric ferric reductase with ascorbate

Dietary iron absorption is regulated by duodenal cytochrome b (Dcytb), an integral membrane protein that catalyzes reduction of nonheme Fe³⁺ by electron transfer from ascorbate across the membrane. This step is essential to enable iron uptake by the divalent metal transporter. Here we report the crystallographic structures of human Dcytb and its complex with ascorbate and Zn²⁺. Each monomer of the homodimeric protein possesses cytoplasmic and apical heme groups, as well as cytoplasmic and apical ascorbate-binding sites located adjacent to each heme. Zn²⁺ coordinates to two hydroxyl groups of the apical ascorbate and to a histidine residue. Biochemical analysis indicates that Fe³⁺ competes with Zn²⁺ for this binding site. These results provide a structural basis for the mechanism by which Fe³⁺ uptake is promoted by reducing agents and should facilitate structure-based development of improved agents for absorption of orally administered iron.

T2 mapping and T2* imaging in heart failure

Cardiovascular magnetic resonance (CMR) is a versatile imaging modality that enables aetiological assessment and provides additional information to that of standard echocardiography in a significant proportion of patients with heart failure. In addition to highly accurate and reproducible assessment of ventricular volumes and replacement fibrosis, multiparametric mapping techniques have rapidly evolved to further expand the diagnostic and prognostic applications in various conditions ranging from acute inflammatory and ischaemic cardiomyopathy, to cardiac involvement in systemic diseases such as sarcoidosis and iron overload cardiomyopathy. In this review, we discuss the established role of T2* imaging and rapidly evolving clinical applications of myocardial T2 mapping as quantitative adjuncts to established qualitative imaging techniques.

Magnetic resonance imaging during management of patients with transfusion-dependent thalassemia: a single-center experience

BACKGROUND

Cardiac and hepatic magnetic resonance imaging evaluation during treatment can tailor physicians' chelation therapy titrations.

AIM

The aim of the study was to assess the relationship of cardiac and hepatic T2* values with chelation therapy in patients with transfusion-dependent thalassemia (TDT).

METHODS

A total of 106 patients with TDT who were followed up in Istanbul Medical Faculty Thalassemia Center were evaluated for the study. Forty-eight (45%) patients with TDT had more than one consecutive MRI examination. The patients were divided into three subgroups according to the cardiac T2* values as the high-risk group (T2* MRI < 10 ms), medium-risk group (T2* MRI 10-20 ms), and the low-risk group (T2* MRI > 20 ms).

RESULTS

The majority of patients used DFX (deferasirox) (79%) and deferiprone (DFP) (17%). Approximately 80% of patients according to cardiac T2* value and 40% of patients according to hepatic T2* value were initially in the low-risk group. Patients with follow-up MRI examinations exhibited significant improvement in liver iron concentration, which correlated with an increase in hepatic T2* values. The decrease of liver iron concentration was prominent in the DFX group (p < 0.01). The serum ferritin level was significantly correlated with liver iron concentrations (rs = 0.65, p < 0.001), hepatic T2* value (rs = - 0.62, p < 0.001), but not with cardiac T2* value (rs = - 0.20, p = 0.07).

CONCLUSION

Cardiovascular and hepatic MRI is a useful follow-up tool during the assessment of risk groups and chelation therapy of patients with TDT. Consecutive MRI tests showed good monitoring of cardiac and liver iron overload.

Synthesis and characterization of methyl substituted 3-hydroxypyridin-4-ones and their complexes with iron(III)

Methyl substituted 3-hydroxypyridin-4(1H)-ones have been synthesized. The pKa values and Fe3+ affinity constants of these ligands were studied. The introduction of an electron-donating methyl group at a different position of pyridinone ring markedly influences the pKa values of 3-hydroxy and 4-oxo groups. The pFe3+ values were also affected and are in the range of 17.6–20.7. The findings can be used to guide a design of 3-hydroxypyridin-4-ones with desirable pKa and pFe3+ values.

Iron overload directly affecting the ovaries in a patient with Diamond-Blackfan anaemia: a case report

Iron is a 'one-way' element and the primary point of regulation of body iron stores is at the level of intestinal iron absorption. Repeated blood transfusions for congenital anaemias bypass this regulatory checkpoint and inevitably lead to iron overload in the long-term. Iron overload causes multi-organ dysfunction of the heart, liver, pancreas and joints. It also causes reproductive toxicity primarily through its damaging effect on the anterior pituitary leading to hypogonadotrophic hypogonadism. Another less understood mechanism of reproductive toxicity is direct gonadal damage of excess free iron. In this article, we present the case of a 24-year-old woman with Diamond-Blackfan anaemia who presented to our unit seeking fertility assistance. The evaluation revealed a combination of hypogonadotrophic hypogonadism and reduced ovarian reserve along with evidence of severe iron overload. A literature search along with input from clinical experts has allowed us to counsel the patient to help her make an informed choice. A multi-disciplinary approach which would include initial optimization of pre-conceptional health with aggressive iron chelation therapy and subsequent ovulation induction with gonadotrophins has been planned, failing which, egg donation may be the only viable alternative.

Optimizing the diagnosis and the treatment of iron overload diseases

A number of human disorders are related to chronic iron overload, either of genetic or acquired origin. The multi-organ damage produced by iron excess leads, in adults and in children, to severe clinical consequences, affecting both quality of life and life expectancy. The diagnosis is increasingly based on a non-invasive strategy, resorting to clinical, biological and imaging data. The treatment rests on either venesection or chelation therapy, depending on the etiology. Major advances in the fields of molecular biology, pharmacology, and biotechnology pave the road for key improvements in the diagnostic and therapeutic management of the patients.

Heart Rate Variability for Early Detection of Cardiac Iron Deposition in Patients with Transfusion-Dependent Thalassemia

Background

Iron overload cardiomyopathy remains the major cause of death in patients with transfusion-dependent thalassemia. Cardiac T2* magnetic resonance imaging is costly yet effective in detecting cardiac iron accumulation in the heart. Heart rate variability (HRV) has been used to evaluate cardiac autonomic function and is depressed in cases of thalassemia. We evaluated whether HRV could be used as an indicator for early identification of cardiac iron deposition.

Methods

One hundred and one patients with transfusion-dependent thalassemia were enrolled in this study. The correlation between recorded HRV and hemoglobin, non-transferrin bound iron (NTBI), serum ferritin and cardiac T2* were evaluated.

Results

The median age was 18 years (range 8–59 years). The patient group with a 5-year mean serum ferritin >5,000 ng/mL included significantly more homozygous β-thalassemia and splenectomized patients, had lower hemoglobin levels, and had more cardiac iron deposit than all other groups. Anemia strongly influenced all domains of HRV. After adjusting for anemia, neither serum ferritin nor NTBI impacted the HRV. However cardiac T2* was an independent predictor of HRV, even after adjusting for anemia. For receiver operative characteristic (ROC) curve analysis of cardiac T2* ≤20 ms, only mean ferritin in the last 12 months and the average of the standard deviation of all R-R intervals for all five-minute segments in the 24-hour recording were predictors for cardiac T2* ≤20 ms, with area under the ROC curve of 0.961 (p<0.0001) and 0.701 (p = 0.05), respectively.

Conclusions

Hemoglobin and cardiac T2* as significant predictors for HRV indicate that anemia and cardiac iron deposition result in cardiac autonomic imbalance. The mean ferritin in the last 12 months could be useful as the best indicator for further evaluation of cardiac risk. The ability of serum ferritin to predict cardiac risk is stronger than observed in other thalassemia cohorts. HRV might be a stronger predictor of cardiac iron in study populations with lower somatic iron burdens and greater prevalence of cardiac iron deposition.

Assessment of Heart and Liver Iron Overload in Thalassemia Major Patients Using T2* Magnetic Resonance Imaging

Accumulation of excess iron in heart can lead to cardiac dysfunction, which is the most common cause of death in thalassemia major patients. Biopsy is an invasive procedure and therefore not an ideal option to assess iron load. However, standard/usual non-invasive methods, such as ferritin measurement, have some limitations and the results show poor correlations with iron load. Magnetic Response Imaging (MRI-T2*), as a non-invasive and reliable method for iron load assessment in organs such as liver and heart, can be suggested as a favorable alternative. This cross-sectional study was implemented in Thalassemia and Hemophilia Clinic Center (Sarvar) affiliated with Mashhad University of Medical Sciences, Mashhad, Iran, from 2012 to 2013. After the approval of the research protocol by the local ethic committee, laboratory tests, including CBC and serum ferritin, were carried out, and echocardiography and heart and liver MRI-T2* were performed. All statistical analysis was done through SPSS software (version 11.5), using independent sample t test and Pearson's correlation coefficient test. A P value ≤0.05 was considered to be significant. 88 patients with the mean (±SD) age of 21.2 (±5.6) years, (range 11-37 years) were observed. Iron load was assessed using MRI-T2* with the following results: Out of 88 patients, 48.9 % had mild to severe cardiac siderosis, and 75.2 % had mild to severe liver siderosis. We demonstrated a correlation between liver MRI-T2* and serum ferritin, and heart MRI-T2* and ejection fraction. However, no correlation between liver and heart MRI-T2* was observed. Heart and liver siderosis is a common and serious problem in thalassemia major patients, and MRI-T2* as a sensitive and non-invasive technique can be used for early/timely detection of siderosis and good therapeutic monitoring in these patients.

Systematic comparison of the mono-, dimethyl- and trimethyl 3-hydroxy-4(1H)-pyridones - Attempted optimization of the orally active iron chelator, deferiprone

A range of close analogues of deferiprone have been synthesised. The group includes mono-, di- and tri-methyl-3-hydroxy-4(1H)-pyridones. These compounds were found to possess similar pFe(3+) values to that of deferiprone, with the exception of the 2.5-dimethylated derivatives. Surprisingly the NH-containing hydroxy-4(1H)-pyridones were found to be marginally more lipophilic than the corresponding N-Me containing analogues. This same group are also metabolised less efficiently by Phase 1 hydroxylating enzymes than the corresponding N-Me analogues. As result of this study, three compounds have been identified for further investigation centred on neutropenia and agranulocytosis.

Mineral Levels in Thalassaemia Major Patients Using Different Iron Chelators

The goal of the present study was to determine the levels of minerals in chronically transfused thalassaemic patients living in Antalya, Turkey and to determine mineral levels in groups using different iron chelators. Three iron chelators deferoxamine, deferiprone and deferasirox have been used to remove iron from patients' tissues. There were contradictory results in the literature about minerals including selenium, zinc, copper, and magnesium in thalassaemia major patients. Blood samples from the 60 thalassaemia major patients (the deferoxamine group, n = 19; the deferiprone group, n = 20 and the deferasirox group, n = 21) and the controls (n = 20) were collected. Levels of selenium, zinc, copper, magnesium, and iron were measured, and all of them except iron showed no significant difference between the controls and the patients regardless of chelator type. Serum copper levels in the deferasirox group were lower than those in the control and deferoxamine groups, and serum magnesium levels in the deferasirox group were higher than those in the control, deferoxamine and deferiprone groups. Iron levels in the patient groups were higher than those in the control group, and iron levels showed a significant correlation with selenium and magnesium levels. Different values of minerals in thalassaemia major patients may be the result of different dietary intake, chelator type, or regional differences in where patients live. That is why minerals may be measured in thalassaemia major patients at intervals, and deficient minerals should be replaced. Being careful about levels of copper and magnesium in thalassaemia major patients using deferasirox seems to be beneficial.

Iron Homeostasis in Health and Disease

Iron is required for the survival of most organisms, including bacteria, plants, and humans. Its homeostasis in mammals must be fine-tuned to avoid iron deficiency with a reduced oxygen transport and diminished activity of Fe-dependent enzymes, and also iron excess that may catalyze the formation of highly reactive hydroxyl radicals, oxidative stress, and programmed cell death. The advance in understanding the main players and mechanisms involved in iron regulation significantly improved since the discovery of genes responsible for hemochromatosis, the IRE/IRPs machinery, and the hepcidin-ferroportin axis. This review provides an update on the molecular mechanisms regulating cellular and systemic Fe homeostasis and their roles in pathophysiologic conditions that involve alterations of iron metabolism, and provides novel therapeutic strategies to prevent the deleterious effect of its deficiency/overload.

Deferoxamine, Cerebrovascular Hemodynamics, and Vascular Aging: Potential Role for Hypoxia-Inducible Transcription Factor-1-Regulated Pathways

BACKGROUND AND PURPOSE

Iron chelation therapy is emerging as a novel neuroprotective strategy. The mechanisms of neuroprotection are diverse and include both neuronal and vascular pathways. We sought to examine the effect of iron chelation on cerebrovascular function in healthy aging and to explore whether hypoxia-inducible transcription factor-1 activation may be temporally correlated with vascular changes.

METHODS

We assessed cerebrovascular function (autoregulation, vasoreactivity, and neurovascular coupling) and serum concentrations of vascular endothelial growth factor and erythropoietin, as representative measures of hypoxia-inducible transcription factor-1 activation, during 6 hours of deferoxamine infusion in 24 young and 24 older healthy volunteers in a randomized, blinded, placebo-controlled cross-over study design. Cerebrovascular function was assessed using the transcranial Doppler ultrasound. Vascular endothelial growth factor and erythropoietin serum protein assays were conducted using the Meso Scale Discovery platform.

RESULTS

Deferoxamine elicited a strong age- and time-dependent increase in the plasma concentrations of erythropoietin and vascular endothelial growth factor, which persisted ≤3 hours post infusion (age effect P=0.04; treatment×time P<0.01). Deferoxamine infusion also resulted in a significant time- and age-dependent improvement in cerebral vasoreactivity (treatment×time P<0.01; age P<0.01) and cerebral autoregulation (gain: age×time×treatment P=0.04).

CONCLUSIONS

Deferoxamine infusion improved cerebrovascular function, particularly in older individuals. The temporal association between improved cerebrovascular function and increased serum vascular endothelial growth factor and erythropoietin concentrations is supportive of shared hypoxia-inducible transcription factor-1-regulated pathways. Therefore, pharmacological activation of hypoxia-inducible transcription factor-1 to enhance cerebrovascular function may be a promising neuroprotective strategy in acute and chronic ischemic syndromes, especially in elderly patients.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT013655104.

Five Years of Deferasirox Therapy for Cardiac Iron in β-Thalassemia Major

Myocardial siderosis in β-thalassemia major (β-TM) remains the leading cause of death. Deferasirox (DFX), a new iron chelation treatment, has proved to be effective in reducing or preventing cardiac iron burden in thalassemic patients according to clinical trials with maximum duration of up to 3 years except one that was recently published and lasted 5 years. The aim of this study was to evaluate the efficacy of DFX in reducing or preventing cardiac iron burden in 23 patients with β-TM after 5 years of therapy. All patients had a magnetic resonance imaging (MRI) T2* evaluation of their cardiac iron load before starting DFX therapy and after a period of 5 years. Ferritin levels and left ventricular ejection fraction (LVEF) were also evaluated at the same time. Deferasirox was administered in a starting dose of 30 mg/kg/day and never increased to more than 40 mg/kg/day. The MRI T2* cardiac iron load mean values before DFX was 32.82 ± 10.86 ms, and after 32.13 ± 7.74 ms, showing a stability in MRI T2* myocardial value but a significant improvement in two patients with an intermediate iron load (12 vs. 23 ms). The mean LVEF value was 68.43 ± 7.08% before treatment with DFX and 67.95 ± 5.94% after DFX therapy without significant change. Our results confirm previous studies that DFX is considered an effective chelating agent used as monotherapy for at least 5 years and is more efficacious in moderate to severe cardiac iron loaded thalassemic patients.

Iron-induced damage in cardiomyopathy: oxidative-dependent and independent mechanisms

The high incidence of cardiomyopathy in patients with hemosiderosis, particularly in transfusional iron overload, strongly indicates that iron accumulation in the heart plays a major role in the process leading to heart failure. In this context, iron-mediated generation of noxious reactive oxygen species is believed to be the most important pathogenetic mechanism determining cardiomyocyte damage, the initiating event of a pathologic progression involving apoptosis, fibrosis, and ultimately cardiac dysfunction. However, recent findings suggest that additional mechanisms involving subcellular organelles and inflammatory mediators are important factors in the development of this disease. Moreover, excess iron can amplify the cardiotoxic effect of other agents or events. Finally, subcellular misdistribution of iron within cardiomyocytes may represent an additional pathway leading to cardiac injury. Recent advances in imaging techniques and chelators development remarkably improved cardiac iron overload detection and treatment, respectively. However, increased understanding of the pathogenic mechanisms of iron overload cardiomyopathy is needed to pave the way for the development of improved therapeutic strategies.