MRI Measurements of Iron Load in Transfusion-Dependent Patients: Implementation, Challenges, and Pitfalls

Association between Transfusion-Related Iron Overload and Liver Fibrosis in Survivors of Pediatric Leukemia: A Cross-Sectional Study

Purpose

Patients who receive frequent blood transfusions are at an elevated risk of developing hepatic fibrosis due to iron overload in the liver. In this study, we evaluated the effectiveness of transient elastography (TE) (FibroScan®) for assessing liver fibrosis in patients with pediatric cancer.

Methods

We enrolled 106 consecutive cases of acute leukemia in individuals under 21 years of age. The participants were followed for 2 years. Based on their serum ferritin (SF) levels, the patients were divided into two groups: group 1 (SF≥300 ng/mL) and group 2 (SF<300 ng/mL). A liver FibroScan® was performed, and a p-value of less than 0.05 was considered statistically significant.

Results

Among the various parameters in the liver function test (LFT), alkaline phosphatase was significantly higher in a subgroup of patients aged 5-8 years in group 2 compared to those in group 1. The indices of liver fibrosis determined by TE, including the FibroScan score, controlled attenuation parameter score, steatosis percentage, and meta-analysis of histological data in viral hepatitis score, as well as indirect serum markers of liver fibrosis such as the aminotransferase (AST)/alanine aminotransferase (ALT) ratio, Fibrosis 4 score, and AST to platelet ratio index, did not differ significantly between the two groups. The association between the TE results and LFT parameters was only significant for ALT.

Conclusion

Transfusion-associated iron overload does not have a significant correlation with severe liver fibrosis. FibroScan® is not a sensitive tool for detecting early stages of fibrosis in survivors of pediatric leukemia.

Speckle tracking echocardiography-derived left ventricular global longitudinal strain in ex-thalassaemics

AIMS

Long term survivors of haematopoietic stem cell transplantation (HSCT) for β-thalassemia major are designated "ex-thalassaemics". Whether ex-thalassaemics continue to harbour residual myocardial dysfunction and thereby stand the risk of heart failure-related morbidity and mortality is unknown. The aim of this study was to assess the prevalence and predictors of subclinical left ventricular (LV) dysfunction in an apparently normal ex-thalassaemic population.

METHODS

We conducted a single centre cross-sectional study among 62 ex-thalassaemic patients, who had undergone HSCT for β-thalassaemia major at our centre. The primary outcome variable was LV systolic dysfunction, as assessed by 1) LV global longitudinal strain (GLS) derived by 2D speckle tracking echocardiography and 2) LV ejection fraction (EF) derived by 2D Simpsons Biplane method.

RESULTS

Among the 62 patients included in the study, 7 [11.3%] were found to have LV systolic dysfunction, all of which were subclinical. Of these, 4 [6.5%] had abnormal GLS and LVEF, 2 [3.2%] had abnormal GLS with normal LVEF, and 1 [1.6%] had abnormal LVEF with low normal mean GLS. There were no statistically significant predictors of LV dysfunction in this cohort.

CONCLUSION

There was a high prevalence of subclinical myocardial dysfunction in the ex-thalassaemic population reiterating the need for close follow up of these patients. 2D Speckle tracking echocardiography-derived LV global longitudinal strain is an effective tool in detecting subclinical myocardial dysfunction in this cohort.

A Ce-MOF@polydopamine composite nanozyme as an efficient scavenger for reactive oxygen species and iron in thalassemia disease therapy

Patients with β-thalassemia are prone to complications such as cardiovascular diseases and secretory gland injury due to iron overload (IO) and reactive oxygen species (ROS) production caused by blood transfusions. Simultaneously scavenging ROS and eliminating IO using nanomedicine remains challenging. Herein, we designed a dual-functional Ce-based metal-organic framework@polydopamine (Ce-MOF@PDA) composite that integrates oxidative stress reduction and IO elimination and evaluated its protective effect on IO injury in thalassemia. Using Ce-MOF with multiple active sites as the core, dopamine, which can coordinate iron ions, was modified on the surface of Ce-MOF and spontaneously polymerized to obtain PDA with iron elimination ability. Dopamine modification also adjusted the Ce3+/Ce4+ ratio to further enhance the catalytic activity for scavenging ROS. Ce-MOF@PDA exhibited multiple nanozyme activities, such as superoxide dismutase- and catalase-like activities, and decreased iron-mediated oxidative stress levels in vitro. Furthermore, the serum ferritin levels and iron concentrations in the liver of IO mice were reduced following treatment with Ce-MOF@PDA, and the fecal clearance ability was comparable to that of deferoxamine. These results indicate that Ce-MOF@PDA can eliminate IO while scavenging ROS and reduce tissue damage caused by oxidative stress. Therefore, the Ce-MOF@PDA nanozyme is a promising therapeutic nanomedicine for treating thalassemia IO.

Longitudinal study of ICET-A on glucose tolerance, insulin sensitivity and β-cell secretion in eleven β-thalassemia major patients with mild iron overload

BACKGROUND

Iron chelation therapy (ICT) is the gold standard for treating patients with iron overload, though its long-term effects are still under evaluation. According to current recommendations regarding  transfusion-dependent  (TD)  β-thalassemia major (β-TM) patients, their serum ferritin (SF) levels should be maintained below 1,000 ng/mL and ICT should be discontinued when the levels are <500 ng/mL in two successive tests. Alternatively, the dose of chelator could be considerably reduced to maintain a balance between iron input and output of  frequent transfusions.

STUDY DESIGN

Due to the paucity of information on long-term effects of ICT  in β-TM with low SF levels on glucose homeostasis, the International Network of Clinicians for Endocrinopathies in Thalassemia and Adolescence Medicine (ICET-A) promoted a retrospective and an ongoing prospective observational study with the primary aim to address the long-term effects of ICT on glucose tolerance and metabolism (β-cell function and peripheral insulin sensitivity) in adult β-TM patients with persistent SF level below 800 ng/mL.

PATIENTS AND METHODS

11 β-TM patients (mean age: 35.5 ± 5.5 years; SF range: 345-777 ng/mL) with normal glucose tolerance test (OGTT) or abnormal glucose tolerance (AGT) for a median of 5.3(1.1-8.3) years.

RESULTS

Abnormal glucose tolerance (AGT) was observed in 7 patients (63.6%) at first observation and ) persisted in 6 patients (54.5%) at last observation. None of them developed diabetes mellitus. AGT was reversed in two patients. One patient with NGT developed early glucose intolerance (1-h PG ≥155 and 2-h PG <140 mg/dL). Three out of  5 patients with isolated impaired glucose tolerance presented a variation of  ATG. Stabilization of low indices for β-cell function and insulin sensitivity/resistance was observed. One patient developed hypogonadotrophic hypogonadism. Three out of 6 patients with SF below 500 ng/dL had hypercalciuria.

CONCLUSION

Despite low SF level, the burden of endocrine complications remains a challenge in β-TM patients. The ability to keep iron at near "normal" level with acceptable risks of toxicity remains to be established.

Use of Deferasirox Film-Coated Tablets in Pediatric Patients with Transfusion Dependent Thalassemia: A Single Center Experience

Thalassemic syndromes are characterized by clinical heterogenicity. For severe disease forms, lifelong blood transfusions remain the mainstay of therapy, while iron overload monitoring and adequate chelation treatment are required in order to ensure effective disease management. Compared to previous chelators, the new deferasirox film-coated tablet (DFX FCT) is considered to offer a more convenient and well-tolerated treatment scheme, aiming at better treatment-related and patient-related outcomes. The present study’s objective was to prospectively evaluate the safety and efficacy of DFX FCT in children and adolescents with transfusion-dependent thalassemia. Data collected included patient demographics, hematology and biochemistry laboratory work up, magnetic resonance imaging of heart and liver for iron load, as well as ophthalmological and audiological examination prior to and a year following drug administration. Study results confirmed DFX FCT safety in older children in a manner similar to adults, but demonstrated increased frequency of adverse events in younger patients, mainly, involving liver function. With regards to efficacy, study results confirmed the preventive role of DFX FCT in iron loading of liver and heart, however, higher doses than generally recommended were required in order to ensure adequate chelation.

Erythrocyte Indices and Hemoglobin Analysis for α-Thalassemia Screening in an Area with High Carrying Rate

Carriers of α-thalassemia exhibit hypochromic microcytosis with mean corpuscular volume (MCV) < 80 fL, mean corpuscular hemoglobin (MCH) < 27 pg, and reduced hemoglobin A₂ (HbA₂). We studied the distribution and diagnostic efficiencies of these indicators and their combinations in patients with and without alpha-thalassemia. Based on genetic diagnosis, 10,883 participants were divided into alpha-thalassemia group (n = 1655) and negative-for-alpha-thalassemia group (n = 9228). Erythrocyte parameters and hemoglobin analysis of the groups were analyzed. Moreover, we compared the four screening schemes (MCV/MCH, MCV/MCH/HbA₂, MCV + MCH, MCV + MCH + HbA₂) to find the best for α-thalassemia screening. The genotypes of --^SEA/αα, and -α^3.7/αα are the most prevalent with 54.9% and 27.6% in Fujian Province, China. There were significant differences in the distribution of MCV, MCH, and HbA₂ in the two groups. Among the three, MCH exhibited the highest sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy. Although the four screening schemes have their advantages, there are significant differences in their sensitivity and specificity. MCV + MCH had the best diagnostic performance (72.6% sensitivity, 89.0% specificity) as well as the highest Youden index (61.59%). Our results showed that MCH could be used to screen α-thalassemia instead of MCV and HbA₂. However, it is recommended that MCV/MCH/HbA₂ screening be used in areas with high α-thalassemia incidence to increased sensitivity.

Comparison of liver MRI R2(FerriScan®) VS liver MRI T2* as a measure of body iron load in a cohort of beta thalassaemia major patients

To compare the similarity of the non-patented T2* and the high cost patented R2 (Ferriscan®) MRI techniques in the measurement of liver iron concentration (LIC) in heavily transfused patients with thalassaemia major in a real- life Sri Lankan hospital setup. We compared LIC measured by MRI, obtained 2 weeks apart, using both T2* and R2 techniques in 15 patients with beta thalassaemia major. They all had a history of > 100 units of blood transfusions life long and also a history of sub optimal chelation. MRI R2 and MRI T2* scan values showed a negative correlation (co-rrelation coefficient = − 0.63, p = 0.01) This correlation was strong in lower LICs and progressively decreased with upper LIC values. Thus a significant discrepancy was observed between median values of two MRI technologies (p = 0.0005) with T2* tending to underestimate iron overload especially in those with very high LIC identified by R2. The lack of concordance of T2* and R2 especially in those with very high reading on R2 suggest the potential errors in interpretations that can occur in “non-expert centres”; which are likely to lead to errors in clinical judgement on the intensity of chelation therapy needed.

MRI as an alternative to serum ferritin for diagnosis of iron overload in children in the context of immune response after stem cell transplantation

Multiple blood cell transfusions may cause iron overload or even liver fibrosis, requiring early diagnosis and intervention. SF is the standard for estimating iron levels in the body, but it also increases with inflammation. We hypothesized that T₂ * magnetic resonance (MR) relaxometry is a more accurate alternative for follow-up in pediatric patients before and after allogenic SCT. Twenty-three children (mean age 10.2 years, 10 female, 13 male) were evaluated prospectively before SCT as well as at least 1 year after SCT with T₂ * relaxometry on a 1.5 T MR-scanner to estimate liver iron concentrations from the T₂ * values ("MR-Fe"). The results were compared with SF, while also considering CRP, and correlated with the number of transfusions. Overall, 24.3 transfusions were administered in average, mainly within 100 days of SCT (mean 10.5 units). Both MR-Fe and SF increased after SCT and decreased in the absence of new transfusions 1 year later without chelate therapy. This suggests regeneration of LP and iron loss, although the original states were not reached. Additionally, simultaneous peaks of CRP and SF were observed directly after SCT. MR-Fe did neither reveal these peaks nor was it associated with CRP (P = .39). We postulate that these early CRP and SF peaks after SCT are probably related to inflammatory reactions and not to iron overload. Thus, SF is not reliable for iron overload diagnosis after SCT in every condition. Beside this interaction, SF and MR-Fe revealed similar accuracy. MRI, however, has practical and economical disadvantages in routine estimation of iron.

Evaluation of hepatic iron concentration heterogeneities using the MRI R2* mapping method

OBJECTIVE

To measure hepatic iron concentration (HIC) heterogeneities using a magnetic resonance R2* mapping method.

PATIENTS AND METHODS

Ninety-four patients with suspected hepatic iron overload and 10 volunteers were included prospectively. A multi-echo R2* sequence with fat saturation and with three post-processing fitting methods (a single exponential decay model with or without truncation, SED and SEDt, and a constant offset model, COS) was compared to a signal intensity ratio method (SIR), considered as the reference. HIC heterogeneity was evaluated from R2* mapping after placing a ROI on each liver segment.

RESULTS

A strong linear correlation between SIR and R2* methods using the SEDt and COS models was observed (r = 0.973 and 0.955, respectively). Volunteers and patient liver variabilities, quantified by mean intra-liver standard deviation (SD) were 1.58 μmol/g (mean range 5.06 μmol/g) and 4.73 μmol/g (mean range 19.08 μmol/g), respectively. For the patient group, the highest HIC was observed in the IV^th segment. Heterogeneity increased for patients with an HIC > 60 μmol/g (mean intra-liver SD = 13.90 μmol/g; mean range = 50.60 μmol/g).

CONCLUSION

This study is the first to demonstrate in vivo HIC heterogeneities using whole-liver mapping analysis. These preliminary results require confirmation through further studies, but might be useful in cases of single ROI analysis.

Evaluation of liver tissue by ultrasound elastography and clinical parameters in children with multiple blood cell transfusions

BACKGROUND

Children receiving multiple blood cell transfusions are prone to iron overload and successive tissue damage in liver parenchyma, making noninvasive screening options desirable. Ultrasound (US) elastography using acoustic radiation force impulse (ARFI) imaging enables evaluation of liver parenchyma stiffness, and MRI allows for quantification of liver iron concentration.

OBJECTIVE

The objective was to correlate US elastography with MRI in children who had undergone bone marrow transplantation and to evaluate the modification of liver tissue with US in combination with clinical parameters at follow-up.

MATERIALS AND METHODS

ARFI, T2*-weighted MRI and a clinical score (HepScore, based on parameters of liver function) were performed in 45 patients (24 male; mean age 9.7 years) before and 100 days and 365 days after transplantation. All received multiple blood transfusions (mean number 22.2 up until 1 year after transplantation). We correlated US findings and HepScore with MRI findings.

RESULTS

We observed signs of iron accumulation in 29/45 (64.4%) patients on MRI (T2*<10 ms) and 15/45 (33.3%) showed increased tissue stiffness (ARFI>5.5 kPa). Correlation of elastography and MRI was not significant (P=0.57; n=51 matched measurements). Comparing US elastography with HepScore in receiver operating characteristic (ROC) curve analysis indicated a cut-off for affected parenchyma if HepScore was >5 points (sensitivity 67%, specificity 68%). Simultaneous increases of both indicated tissue alteration.

CONCLUSION

Combining US and HepScore enabled detection of liver tissue alteration through iron overload, but we found no direct significant effect of estimated iron from MRI on ARFI imaging.

Absorption, distribution, metabolism and excretion of the biomaterials used in Nanocarrier drug delivery systems

Nanocarriers (NCs) are a type of drug delivery system commonly used to regulate the pharmacokinetic and pharmacodynamic properties of drugs. Although a wide variety of NCs has been developed, relatively few have been registered for clinical trials and even fewer are clinically approved. Overt or potential toxicity, indistinct mechanisms of drug release and unsatisfactory pharmacokinetic behavior all contribute to their high failure rate during preclinical and clinical testing. These negative characteristics are not only due to the NCs themselves but also to the materials of the drug nanocarrier system (MDNS) that are released in vivo. In this article, we review the main analytical techniques used for bioassay of NCs and MDNS and their pharmacokinetics after administration by various routes. We anticipate our review will serve to improve the understanding of MDNS pharmacokinetics and facilitate the development of NC drug delivery systems.

Increased Prevalence of Thalassemia in Young People in Korea: Impact of Increasing Immigration

Background

Thalassemia is highly prevalent in Southeast Asia but is rare in Korea; however, Southeast Asian immigrant population is recently rising in Korea. We investigated the prevalence of thalassemia in Korea in the context of increasing immigration.

Methods

This prospective, observational, multicenter study was conducted between September 2015 and August 2017. A total of 669 subjects <30 years living in Korea were grouped into the multiethnic (N=314) and Korean (N=355) groups. Hb electrophoresis and complete blood count (CBC) were performed. If low mean corpuscular volume with high red blood cell distribution width coefficient of variation or a high fetal Hb (HbF) or Hb alpha 2 (HbA₂) level was observed, genetic testing of the α- and β-globin genes was performed. In addition, the number of potential thalassemia carriers in Korea was estimated by multiplying the prevalence of thalassemia in a specific ethnicity by the number of immigrants of that ethnicity.

Results

Twenty-six multiethnic and 10 Korean subjects showed abnormal results for Hb electrophoresis and CBC. Eighteen multiethnic subjects and four Korean subjects were tested for α-globin and β-globin gene mutations. Within the multiethnic group, five subjects (1.5%) were α-thalassemia carriers, and six (1.9%) were β-thalassemia minor. The SEA deletion in HBA1 and HBA2, and c. 126_129delCTTT (p.Phe42Leufs*19) mutation of HBB were the dominant inherited mutations.

Conclusions

The prevalence of thalassemia in young people in Korea is increasing due to the increasing number of Southeast Asian immigrants.

Treatment Options for Sickle Cell Disease

Sickle cell disease (SCD) complications begin with the polymerization of sickle hemoglobin (HbS). Thus, SCD therapies are focused on preventing HbS production or reducing the circulating amount of HbS. Hydroxyurea treatment has become more widespread, whereas the number of evidence-based indications for erythrocyte transfusion is small. Hematopoietic stem cell transplant is a curative option for SCD but less than 25% of patients have a suitable donor. This article focuses on supportive and preventive care improvements and the benefits of hydroxyurea. Indications for erythrocyte transfusion, hematopoietic stem cell transplant, and gene therapy trials are also summarized.

Diagnosis, management and response criteria of iron overload in myelodysplastic syndromes (MDS): updated recommendations of the Austrian MDS platform

INTRODUCTION

Despite the availability of effective iron chelators, transfusion-related morbidity is still a challenge in chronically transfused patients with myelodysplastic syndromes (MDS). In these patients, transfusion-induced iron overload may lead to organ dysfunction or even organ failure. In addition, iron overload is associated with reduced overall survival in MDS. Areas covered: During the past 10 years, various guidelines for the management of MDS patients with iron overload have been proposed. In the present article, we provide our updated recommendations for the diagnosis, prevention and therapy of iron overload in MDS. In addition, we propose refined treatment response criteria. As in 2006 and 2007, recommendations were discussed and formulated by participants of our Austrian MDS platform in a series of meetings in 2016 and 2017. Expert commentary: Our updated recommendations should support early recognition of iron overload, optimal patient management and the measurement of clinical responses to chelation treatment in daily practice.

Advances in iron chelation therapy: transitioning to a new oral formulation

Iron overload is a concern for patients who require repeated red-blood-cell transfusions due to conditions such as sickle cell disease, thalassemia, or myelodysplastic syndromes. The recommended treatment for removing excess iron in these patients is iron chelation therapy. Currently available iron chelators include deferoxamine, which is administered by injection, and deferasirox and deferiprone, both of which are administered orally. Adherence to iron chelator therapy is an important consideration and may be affected by side effects. A new formulation of deferasirox, a film-coated tablet (FCT), has the potential to improve adherence by offering greater flexibility in administration compared with the original formulation of deferasirox, a dispersible tablet (DT) for oral suspension. This review provides an overview of the currently available iron chelator formulations, with a focus on a comparison between deferasirox DT for oral suspension and deferasirox FCT. The new formulation may be associated with fewer side effects and has increased bioavailability. In addition, alternative strategies for iron chelation, such as combining two different iron chelators, will be discussed.

Clinical quantitative susceptibility mapping (QSM): Biometal imaging and its emerging roles in patient care

Quantitative susceptibility mapping (QSM) has enabled magnetic resonance imaging (MRI) of tissue magnetic susceptibility to advance from simple qualitative detection of hypointense blooming artifacts to precise quantitative measurement of spatial biodistributions. QSM technology may be regarded to be sufficiently developed and validated to warrant wide dissemination for clinical applications of imaging isotropic susceptibility, which is dominated by metals in tissue, including iron and calcium. These biometals are highly regulated as vital participants in normal cellular biochemistry, and their dysregulations are manifested in a variety of pathologic processes. Therefore, QSM can be used to assess important tissue functions and disease. To facilitate QSM clinical translation, this review aims to organize pertinent information for implementing a robust automated QSM technique in routine MRI practice and to summarize available knowledge on diseases for which QSM can be used to improve patient care. In brief, QSM can be generated with postprocessing whenever gradient echo MRI is performed. QSM can be useful for diseases that involve neurodegeneration, inflammation, hemorrhage, abnormal oxygen consumption, substantial alterations in highly paramagnetic cellular iron, bone mineralization, or pathologic calcification; and for all disorders in which MRI diagnosis or surveillance requires contrast agent injection. Clinicians may consider integrating QSM into their routine imaging practices by including gradient echo sequences in all relevant MRI protocols.

LEVEL OF EVIDENCE

1 Technical Efficacy: Stage 5 J. Magn. Reson. Imaging 2017;46:951-971.

Iron mediated toxicity and programmed cell death: A review and a re-examination of existing paradigms

Iron is an essential micronutrient that is problematic for biological systems since it is toxic as it generates free radicals by interconverting between ferrous (Fe²⁺) and ferric (Fe³⁺) forms. Additionally, even though iron is abundant, it is largely insoluble so cells must treat biologically available iron as a valuable commodity. Thus elaborate mechanisms have evolved to absorb, re-cycle and store iron while minimizing toxicity. Focusing on rarely encountered situations, most of the existing literature suggests that iron toxicity is common. A more nuanced examination clearly demonstrates that existing regulatory processes are more than adequate to limit the toxicity of iron even in response to iron overload. Only under pathological or artificially harsh situations of exposure to excess iron does it become problematic. Here we review iron metabolism and its toxicity as well as the literature demonstrating that intracellular iron is not toxic but a stress responsive programmed cell death-inducing second messenger.