Clinical consequences of iron overload from chronic red blood cell transfusions, its diagnosis, and its management by chelation therapy

Iron Overload in Children With Leukemia; Identification of a Cutoff Value for Serum Ferritin Level

OBJECTIVE

To determine the prevalence of iron overload in children with acute lymphoblastic leukemia (ALL) after treatment cessation and establish a cutoff value for serum ferritin level as an indicator of iron overload.

BACKGROUND

Early detection and monitoring of iron overload in patients with leukemia is crucial.

METHODS

In this prospective cohort study, 66 pediatric patients with ALL who were treated at a tertiary referral center affiliated with Shiraz University of Medical Sciences in Shiraz, Southern Iran, were investigated from July 2020 to December 2022. Serum ferritin levels were measured 6 months after treatment completion. T2* magnetic resonance imaging of the liver and heart was done for all patients. The receiver operating characteristic curve was used to illustrate the area under the receiver operating characteristic curve to assess the diagnostic value of serum ferritin level and total transfusion volume.

RESULTS

A total of 24 patients (36.4%) had iron overload in the heart or liver based on T2 magnetic resonance imaging findings. Serum ferritin level was a highly accurate diagnostic marker for iron overload in pediatric patients with ALL, with a sensitivity of 95.8%, and specificity of 85.7% for a cutoff value of 238.5 ng/mL. Also, blood transfusion was a good predictor of iron overload a sensitivity of 75% and specificity of 81% for a cutoff value of 28.3 mL/kg.

CONCLUSION

We identified specific cutoff values for serum ferritin and blood transfusion volume to predict iron overload with high sensitivity and specificity. These markers offer a cost-effective and accessible approach for periodic screening of iron deposition, particularly in resource-constrained settings.

Correlation of Transient Elastography with Liver Iron Concentration and Serum Ferritin Levels in Patients with Transfusion-Dependent Thalassemia Major from Oman

Aims

In a longitudinal study, we aimed to assess the correlation between ultrasound transient elastography (TE), serum ferritin (SF), liver iron content (LIC) by magnetic resonance imaging (MRI) T2* along with the fibrosis-4 (FIB-4) score as a screening tool to detect significant liver fibrosis among chronically transfusion-dependent beta-thalassemia (TDT) patients.

Methods

The study was conducted at a tertiary health center treating TDT patients. Transient elastography was performed within 3 months of Liver MRI T2* examinations at the radiology department over a median of one-year duration. T-test for independent data or Mann-Whitney U test was used to analyze group differences. Spearman correlation with linear regression analysis was used to evaluate the correlation between TE liver stiffness measurements, Liver MRI T2* values, and SF levels.

Results

In this study on 91 patients, the median age (IQR) of the subjects was 33 (9) years, and the median (IQR) body mass index was 23.8 (6.1) kg/m2. Median (IQR) TE by fibroscan, MRI T2*(3T), Liver iron concentration (LIC) by MRI Liver T2*, and SF levels were 6.38 (2.6) kPa, 32.4 (18) milliseconds, 7(9) g/dry wt., and 1881 (2969) ng/mL, respectively. TE measurements correlated with LIC g/dry wt. (rS =0.39, p=0.0001) and with SF level (rS =0.43, P=0.001) but not with MRI T2* values (rS =-0.24; P=0.98).

Conclusion

In TDT patients, liver stiffness measured as TE decreased significantly with improved iron overload measured as LIC by MRI and SF levels. However, there was no correlation of TE with the fibrosis-4 (FIB-4) score.

Rate of Change of Liver Iron Content by MR Imaging Methods: A Comparison Study

Objective: Magnetic resonance imaging (MRI) can accurately quantify liver iron concentration (LIC), eliminating the need for an invasive liver biopsy. Currently, the most widely used relaxometry methods for iron quantification are R2 and R2*, which are based on T2 and T2* acquisition sequences, respectively. We compared the rate of change of LIC as measured by the R2-based, FDA-approved commercially available third-party software with the rate of change of LIC measured by in-house analysis using R2*-relaxometry-based MR imaging in patients undergoing follow-up MRI scans for liver iron estimation. Methods: We retrospectively included patients who had undergone serial MRIs for liver iron estimation. The MR studies were performed on a 1.5T scanner; standard multi-slice, multi-echo T2- and T2*-based sequences were acquired, and LIC was estimated. The comparison between the rate of change of LIC by R2 and R2* values was performed via correlation coefficients and Bland−Altman difference plots. Results: One hundred and eighty-nine MR abdomen studies for liver iron evaluation from 81 patients (male: 38; female: 43) were included in the study. Fifty-nine patients had two serial scans, eighteen patients had three serial scans, three patients had four serial scans, and one patient had five serial scans. The average time interval between the first and last scans for each patient was 13.3 months. The average rates of change of LIC via R2 and R2* methods were −0.0043 ± 0.0214 and −0.0047 ± 0.012 mg/g per month, respectively. There was no significant difference in the rate of change of LIC observed between the two methods. Linearity between the rate of change of LIC measured by R2 (LIC R2) and R2* (LIC R2*) was strong, showing a correlation coefficient of r = 0.72, p < 0.01. A Bland−Altman plot between the rate of change of the two methods showed that the majority of the plotted variables were between two standard deviations. Conclusion: There was no significant difference in the rate of change of LIC detected between the R2 method and the R2* method that uses a gradient echo (GRE) sequence acquired with breath-hold. Since R2* is relatively faster and less prone to motion artifacts, R2*-derived LIC is recommended for iron homeostasis follow-up in patients with liver iron overload.

Dose of deferasirox correlates with its effects, which differ between low-risk myelodysplastic syndrome and aplastic anaemia

WHAT IS KNOWN AND OBJECTIVE

Patients with low-risk myelodysplastic syndrome (MDS) and aplastic anaemia (AA) often need transfusions, which may accelerate iron overload. The aim of this study was to evaluate the efficacy, safety and dose-effect relationships of deferasirox (DFX) in patients with low-risk MDS and AA who were refractory to regular treatment in a real-world setting.

METHODS

Patient data were recorded, and dose-effect relationships of DFX were calculated after the first 6 months. Total annual exposure to DFX was calculated after 12 months and expressed as the accumulated exposure time at a dosage of 20 mg/kg/day.

RESULTS AND DISCUSSION

Sixty-one patients with low-risk MDS and 51 with AA were enrolled. The minimum dosage of DFX needed for a significant serum ferritin (SF) decrease was 20 mg/kg/day at 6 months, and the minimum accumulation of DFX had to reach 9 months at 20 mg/kg/day by 12 months for patients with low-risk MDS. For patients with AA, the minimum dosage was 10 mg/kg/day at 6 months, and the minimum accumulation had to reach 3 months at 20 mg/kg/day by 12 months. With the same exposure, significant improvements in haematological parameters were also observed in AA. Lower liver enzymes compared with baseline were observed. Gastrointestinal disorders and elevated serum creatinine were the most common side effects. Higher exposure to DFX correlated with longer overall survival (OS).

WHAT IS NEW AND CONCLUSION

A significant decrease in SF and an improvement in haematologic parameters, organ function and even OS can be achieved if the accumulated DFX dose reaches a certain level. Patients with low-risk MDS need a higher dose than those with AA.

Iron Effects on Clostridioides difficile Toxin Production and Antimicrobial Susceptibilities

Despite the benefits of red blood cell (RBC) transfusion therapy, it can render patients vulnerable to iron overload. The excess iron deposits in various body tissues cause severe complications and organ damage such as cardiotoxicity and mold infections. Clostridioides difficile infection (CDI) is the most common cause of nosocomial diarrhea among cancer patients and is associated with significant morbidity and mortality. Our study aims to determine the role of iron overload and the effects of iron chelators on CDI. Our results demonstrated that iron (Fe3+) stimulated the growth of C. difficile with increased colony formation units (CFU) in a dose-dependent manner. Exposure to excess iron also increased the gene expression levels of tcdA and tcdB. The production of C. difficile toxin A, necessary for the pathogenesis of C. difficile, was also elevated after iron treatment. In the presence of excess iron, C. difficile becomes less susceptible to metronidazole with significantly elevated minimum inhibitory concentration (MIC) but remains susceptible to vancomycin. Iron-stimulated colony formation and production of C. difficile toxins were effectively diminished by iron chelator deferoxamine co-treatment. Incorporating iron overload status as a potential factor in developing a risk prediction model of CDI and antibiotic treatment response may aid clinical practitioners in optimizing CDI management in oncology patients.

The Toxic Influence of Excess Free Iron on Red Blood Cells in the Biophysical Experiment: An In Vitro Study

Iron is needed for life-essential processes, but free iron overload causes dangerous clinical consequences. The study of the role of red blood cells (RBCs) in the influence of excess free iron in the blood on the pathological consequences in an organism is relevant. Here, in a direct biophysical experiment in vitro, we studied the action of free iron overload on the packed red blood cell (pRBC) characteristics. In experiments, we incubated pRBCs with the ferrous sulfate solution (Fe²⁺). Wе used free iron in a wide range of concentrations. High Fe²⁺ concentrations made us possible to establish the pattern of the toxic effect of excess iron on pRBCs during a reduced incubation time in a biophysical experiment in vitro. It was found that excess free iron causes changes in pRBC morphology, the appearance of bridges between cells, and the formation of clots, increasing the membrane stiffness and methemoglobin concentration. We created a kinetic model of changes in the hemoglobin derivatives. The complex of simultaneous distortions of pRBCs established in our experiments can be taken into account when studying the mechanism of the toxic influence of excess free iron in the blood on pathological changes in an organism.

Hemosiderin Accumulation in Liver Decreases Iron Availability in Tachycardia-Induced Porcine Congestive Heart Failure Model

Despite advances in the management of iron deficiency in heart failure (HF), the mechanisms underlying the effects of treatment remain to be established. Iron distribution and metabolism in HF pathogenesis need to be clarified. We used a porcine tachycardia-induced cardiomyopathy model to find out how HF development influences hepatic and myocardial iron storing, focusing on ferritin, the main iron storage protein. We found that cumulative liver congestion (due to the decrease of heart function) overwhelms its capacity to recycle iron from erythrocytes. As a consequence, iron is trapped in the liver as poorly mobilized hemosiderin. What is more, the ferritin-bound Fe³⁺ (reflecting bioavailable iron stores), and assembled ferritin (reflecting ability to store iron) are decreased in HF progression in the liver. We demonstrate that while HF pigs show iron deficiency indices, erythropoiesis is enhanced. Renin–angiotensin–aldosterone system activation and hepatic hepcidin suppression might indicate stress erythropoiesisinduced in HF. Furthermore, assembled ferritin increases but ferritin-bound Fe³⁺ is reduced in myocardium, indicating that a failing heart increases the iron storage reserve but iron deficiency leads to a drop in myocardial iron stores. Together, HF in pigs leads to down-regulated iron bioavailability and reduced hepatic iron storage making iron unavailable for systemic/cardiac needs.

Conservative Management of Hyperferritinemia in Hemolytic Disease of the Fetus and Newborn: A Case Report and Review of the Literature

We report a newborn with hemolytic disease of the fetus and newborn (HDFN) with rapid resolution of extreme hyperferritinemia without chelation. An infant born at 35+3 weeks with HDFN and a history of 3 intrauterine transfusions developed severe hyperferritinemia (maximum, 8258 mcg/L) without evidence of toxic iron deposition on liver biopsy. Her hyperferritinemia was managed with observation alone, and ferritin levels normalized rapidly. This case supports observation as being the preferred alternative to chelation therapy for significant hyperferritinemia in newborns with HDFN in the absence of demonstrated toxic end-organ iron deposition. We also include a review of the related available literature.

Iron Therapy in Chronic Kidney Disease: Days of Future Past

Anemia affects millions of patients with chronic kidney disease (CKD) and prompt iron supplementation can lead to reductions in the required dose of erythropoiesis-stimulating agents, thereby reducing medical costs. Oral and intravenous (IV) traditional iron preparations are considered far from ideal, primarily due to gastrointestinal intolerability and the potential risk of infusion reactions, respectively. Fortunately, the emergence of novel iron replacement therapies has engendered a paradigm shift in the treatment of iron deficiency anemia in patients with CKD. For example, oral ferric citrate is an efficacious and safe phosphate binder that increases iron stores to maintain hemoglobin levels. Additional benefits include reductions in fibroblast growth factor 23 levels and the activation of 1,25 dihydroxyvitamin D. The new-generation IV iron preparations ferumoxytol, iron isomaltoside 1000, and ferric carboxymaltose are characterized by a reduced risk of infusion reactions and are clinically well tolerated as a rapid high-dose infusion. In patients undergoing hemodialysis (HD), ferric pyrophosphate citrate (FPC) administered through dialysate enables the replacement of ongoing uremic and HD-related iron loss. FPC transports iron directly to transferrin, bypassing the reticuloendothelial system and avoiding iron sequestration. Moreover, this paper summarizes recent advancements of hypoxia-inducible factor prolyl hydroxylase inhibitors and future perspectives in renal anemia management.

Dual-energy CT in diffuse liver disease: is there a role?

Dual-energy CT (DECT) can be defined as the use of two different energy levels to identify and quantify material composition. Since its inception, DECT has benefited from remarkable improvements in hardware and clinical applications. DECT enables accurate identification and quantification of multiple materials, including fat, iron, and iodine. As a consequence, multiple studies have investigated the potential role of DECT in the assessment of diffuse liver diseases. While this role is evolving, this article aims to review the most relevant literature on use of DECT for assessment of diffuse liver diseases. Moreover, the basic concepts on DECT techniques, types of image reconstruction, and DECT-dedicated software will be described, focusing on the areas that are most relevant for the evaluation of diffuse liver diseases. Also, we will review the evidence of added value of DECT in detection and assessment of hepatocellular carcinoma which is a known risk in patients with diffuse liver disease.

Real-World Experience Measurement of Liver Iron Concentration by R2 vs. R2 Star MRI in Hemoglobinopathies

Background: Non-invasive determination of liver iron concentration (LIC) is a valuable tool that guides iron chelation therapy in transfusion-dependent patients. Multiple methods have been utilized to measure LIC by MRI. The purpose of this study was to compare free breathing R2* (1/T2*) to whole-liver Ferriscan R2 method for estimation of LIC in a pediatric and young adult population who predominantly have hemoglobinopathies. Methods: Clinical liver and cardiac MRI scans from April 2016 to May 2018 on a Phillips 1.5 T scanner were reviewed. Free breathing T2 and T2* weighted images were acquired on each patient. For T2, multi-slice spin echo sequences were obtained. For T2*, a single mid-liver slice fast gradient echo was performed starting at 0.6 ms with 1.2 ms increments with signal averaging. R2 measurements were performed by Ferriscan analysis. R2* measurements were performed by quantitative T2* map analysis. Results: 107 patients underwent liver scans with the following diagnoses: 76 sickle cell anemia, 20 Thalassemia, 9 malignancies and 2 Blackfan Diamond anemia. Mean age was 12.5 ± 4.5 years. Average scan time for R2 sequences was 10 min, while R2* sequence time was 20 s. R2* estimation of LIC correlated closely with R2 with a correlation coefficient of 0.94. Agreement was strongest for LIC < 15 mg Fe/g dry weight. Overall bias from Bland–Altman plot was 0.66 with a standard deviation of 2.8 and 95% limits of agreement −4.8 to 6.1. Conclusion: LIC estimation by R2* correlates well with R2-Ferriscan in the pediatric age group. Due to the very short scan time of R2*, it allows imaging without sedation or anesthesia. Cardiac involvement was uncommon in this cohort.

Erythroferrone, the new iron regulator: evaluation of its levels in Egyptian patients with beta thalassemia

Since iron overload is the commonest cause of morbidity and mortality in β thalassemia major (β-TM), it represents one major target in therapeutic management of the disease. The recently discovered erythroid regulator, erythroferrone (ERFE), governed by high levels of erythropoietin, was found to suppress hepcidin expression, thus increasing iron availability for developing erythroid progenitors. We aimed to investigate ERFE levels in Egyptian β-TM patients as an attempt to understand its role in the prediction of iron overload states. Our study included 70 β-TM patients, divided into two subgroups according to the degree of iron overload, and 30 sex and age-matched healthy subjects. ERFE gene expression was analyzed by quantitative real-time polymerase chain reaction (qRT-PCR), and serum hepcidin was measured using enzyme-linked immunosorbent assay (ELISA) technique. Both ERFE gene expression levels and transferrin saturation (TS%) values were able to discriminate among cases with different degrees of iron overload, in contrast to hepcidin. TS% was acknowledged as the best predictor of iron overload (AUC 0.893) in comparison with serum hepcidin and ERFE gene levels (AUC 0.807 and 0.677, respectively), and ERFE gene expression was an independent predictor for the estimated TS%. In conclusion, we suggest that using the ERFE gene expression, combined with serum hepcidin estimation, can substantiate the role of estimated TS% as a promising tool in screening for iron overload in β-TM patients.

Adherence to iron chelation therapy in patients who switched from deferasirox dispersible tablets to deferasirox film-coated tablets

OBJECTIVE

To compare real-world adherence to and persistence with deferasirox film-coated tablets (DFX-FCT) and deferasirox dispersible tablets (DFX-DT) among patients who switched from DFX-DT to DFX-FCT, overall and by disease type (sickle cell disease [SCD], thalassemia, and myelodysplastic syndrome [MDS]).

METHODS

Patients were ≥2 years old and had ≥2 DFX-FCT claims over the study period and ≥2 DFX-DT claims before the index date (first DFX-FCT claim). The DFX-DT period was defined from the first DFX-DT claim to the index date; the DFX-FCT period was defined from the index date to the end of the study period. Adherence was measured as medication possession ratio (MPR) and proportion of days covered (PDC). Persistence was defined as continuous medication use without a gap ≥30 or 60 days between refills. Comparisons were conducted using paired-sample Wilcoxon sign-rank and McNemar's tests.

RESULTS

In total, 606 patients were selected (SCD: 348; thalassemia: 107; MDS: 106; other: 45). Adherence and persistence in the DFX-FCT vs DFX-DT period was significantly higher across all measures: mean MPR was 0.80 vs 0.76 (p < .001); 60.9% vs 54.3% of patients had MPR ≥ 0.8 (p = .009); mean 3-month PDC was 0.83 vs 0.71 (p < .001); 64.2% vs 45.4% of patients had 3-month PDC ≥ 0.8 (p < .001); 87.2% vs 63.4% of patients had 3-month persistence with no gap ≥30 days and 96.1% vs 79.9% with no gap ≥60 days (p < .001). Adherence and persistence improved after switching across all diseases, particularly MDS.

CONCLUSIONS

Adherence and persistence improved significantly after switching from DFX-DT to DFX-FCT for all diseases, but especially MDS.

Hepcidin Protects against Lethal Escherichia coli Sepsis in Mice Inoculated with Isolates from Septic Patients

Iron is an essential micronutrient for most microbes and their hosts. Mammalian hosts respond to infection by inducing the iron-regulatory hormone hepcidin, which causes iron sequestration and a rapid decrease in the plasma and extracellular iron concentration (hypoferremia). Previous studies showed that hepcidin regulation of iron is essential for protection from infection-associated mortality with the siderophilic pathogens Yersinia enterocolitica and Vibrio vulnificus However, the evolutionary conservation of the hypoferremic response to infection suggests that not only rare siderophilic bacteria but also common pathogens may be targeted by this mechanism. We tested 10 clinical isolates of Escherichia coli from children with sepsis and found that both genetic iron overload (by hepcidin-1 knockout [HKO]) and iatrogenic iron overload (by intravenous iron) potentiated infection with 8 out of the 10 studied isolates: after peritoneal injection of E. coli, iron-loaded mice developed sepsis with 60% to 100% mortality within 24 h, while control wild-type mice suffered 0% mortality. Using one strain for more detailed study, we show that iron overload allows rapid bacterial multiplication and dissemination. We further found that the presence of non-transferrin-bound iron (NTBI) in the circulation is more important than total plasma or tissue iron in rendering mice susceptible to infection and mortality. Postinfection treatment of HKO mice with just two doses of the hepcidin agonist PR73 abolished NTBI and completely prevented sepsis-associated mortality. We demonstrate that the siderophilic phenotype extends to clinically common pathogens. The use of hepcidin agonists promises to be an effective early intervention in patients with infections and dysregulated iron metabolism.

Assessing the spatial pattern of iron in well water from a small central Florida community

Iron is one of the most common elements in the Earth's crust, which corresponds to it being a common constituent in drinking water supplies. Residents of Bithlo, an unincorporated community in east-central Florida, have observed that their drinking water tastes like metal and stains clothing and teeth. An evaluation of water samples collected from over 200 private drinking water wells revealed iron concentrations that exceeded the US Environmental Protection Agency's (EPA's) secondary standard of 0.3 mg/L. Households with and without point-of-entry treatment were found to have over three times (0.92 mg/L) and ten times (3.86 mg/L) more iron than the EPA's secondary standard, respectively. The human health-based threshold of 4.2 mg/L established by the Centers for Disease Control and Prevention was exceeded in 38.6% of untreated residences. Community-wide statistical and spatial water-quality trends were developed by combining the collected well water quality data with historically available water quality reports. Spatial analyses revealed that greater than 99% of the Bithlo community's private household supplies would exceed the EPA's drinking water secondary standard.

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.

Utility of Transient Elastography in Estimating Hepatic Iron Concentration in Comparison to Magnetic Resonance Imaging in Patients Who are Transfusion-Dependent: A Canadian Center Experience

Transfusion-dependent hereditary anemias such as β-thalassemia (β-thal), predispose patients to iron overload and its numerous clinical sequelae. Accurate assessment of overall iron status and prompt initiation of chelation therapy to prevent irreversible end-organ damage can be achieved using magnetic resonance imaging (MRI) to measure liver iron concentration (LIC) as a surrogate marker of total body iron; however, its access may be associated with long wait times and delay in treatment. We report an observational cohort study at a single tertiary care center assessing the theoretical role of transient elastography (TE), which measures liver stiffness, in estimating LIC compared to other established diagnostic measures. While regression analyses confirm a moderate correlation between LIC per R2 MRI and serum ferritin level (pooled estimate of correlation = 0.55), there was no significant correlation between TE reading and LIC based on R2 MRI (pooled estimate of correlation = -0.06), and only a weak correlation was observed with serum ferritin level (pooled estimate of correlation = 0.45). These results suggest TE may not be sensitive enough to detect subtle changes in the hepatic parenchymal stiffness associated with liver iron deposition.

Packed red blood cell transfusions as a risk factor for parenteral nutrition associated liver disease in premature infants

AIM

To determine if packed red blood cell transfusions contribute to the development of parenteral nutrition associated liver disease.

METHODS

A retrospective chart review of 49 premature infants on parenteral nutrition for > 30 d who received packed red blood cell (PRBC) transfusions was performed. Parenteral nutrition associated liver disease was primarily defined by direct bilirubin (db) > 2.0 mg/dL. A high transfusion cohort was defined as receiving > 75 mL packed red blood cells (the median value). Kaplan-Meier plots estimated the median volume of packed red blood cells received in order to develop parenteral nutrition associated liver disease.

RESULTS

Parenteral nutritional associated liver disease (PNALD) was noted in 21 (43%) infants based on db. Among the 27 high transfusion infants, PNALD was present in 17 (64%) based on elevated direct bilirubin which was significantly greater than the low transfusion recipients. About 50% of the infants, who were transfused 101-125 mL packed red blood cells, developed PNALD based on elevation of direct bilirubin. All infants who were transfused more than 200 mL of packed red blood cells developed PNALD. Similar results were seen when using elevation of aspartate transaminase or alanine transaminase to define PNALD.

CONCLUSION

In this retrospective, pilot study there was a statistically significant correlation between the volume of PRBC transfusions received by premature infants and the development of PNALD.

Iron Overload and Platelet Function Defects: Possible Correlation

Acquired platelet function defect might be a consequence of iron overload. Even though there are various complications of iron overload, only few reports have indicated some correlations with platelets dysfunction. We report a child with Diamond-Blackfan anemia who has significant complications from iron overload due to chronic blood transfusion, and one of these complications is acquired platelet function defect that manifests with frequent episodes of epistaxis. Therefore, we emphasize the necessity for further studies to confirm direct correlation between iron overload as a causative agent and platelets dysfunction. And we recommend screening for platelets function in patients receiving chronic blood transfusion aiming at possible prevention of any life-threatening bleeding.

Conditions associated with extreme hyperferritinaemia (>3000 μg/L) in adults

BACKGROUND

The clinical significance of extreme hyperferritinaemia has come under scrutiny with the increasing recognition of haemophagocytic lymphohistiocytosis (HLH) in adults. Most studies of hyperferritinaemia have focused on serum ferritin greater than 1000 μg/L, often in ambulatory patients. The conditions associated with more extreme hyperferritinaemia are poorly understood.

AIMS

To examine conditions associated with extreme hyperferritinaemia greater than 3000 μg/L in acutely ill adults at a quaternary care hospital.

METHODS

Patients with serum ferritin greater than 3000 μg/L at Vancouver General Hospital between 1 August 2011 and 1 August 2012 were identified. Those over 18 years of age and with clinical data available were included in the study.

RESULTS

Eighty-three subjects were identified. Twenty-one cases (25%) were due to transfusional iron overload, 16 (19%) due to liver disease and 15 (18%) due to mixed factors. Haemophagocytic lymphohistiocytosis (HLH) was diagnosed in six of 83 patients (7%) with ferritin greater than 3000 μg/L, but six of eight patients (75%) with ferritin greater than 20 000 μg/L.

CONCLUSIONS

Extreme hyperferritinaemia greater than 3000 μg/L is uncommon in adult patients. The highest serum ferritin values are seen in HLH, but the differential diagnosis for serum ferritin greater than 3000 μg/L remains broad with iron overload and liver disease being the most common causes.

Transfusion practices and infectious risks

Transfusion-transmitted infections remain among the most-feared complications of allogeneic blood transfusion. Thanks to several strategies including donor screening and deferral, blood testing and pathogen inactivation, their risks have reached all-time low levels, particularly in developed nations. Nonetheless, new and emerging infections remain a threat that is likely to exacerbate in the coming years with continued globalization and climate change. More effective strategies of pathogen inactivation and more vigilant horizon screening are hoped to abate the risk. Additionally, allogeneic transfusion has repeatedly been shown to be associated with worsening of outcomes in patients, including the documented increased risk of infections (often nosocomial) in recipients of transfusions. The underlying mechanism is likely to be related to immunosuppressive effects of allogeneic blood, iron content, and bacterial contamination. This issue is best addressed by more judicious and evidence-based use of allogeneic blood components to ensure the potential benefits outweigh the risks.

Retrospective comparison of gradient recalled echo R2* and spin-echo R2 magnetic resonance analysis methods for estimating liver iron content in children and adolescents

BACKGROUND

Serial surveillance of liver iron concentration (LIC) provides guidance for chelation therapy in patients with iron overload. The diagnosis of iron overload traditionally relies on core liver biopsy, which is limited by invasiveness, sampling error, cost and general poor acceptance by pediatric patients and parents. Thus noninvasive diagnostic methods such as MRI are highly attractive for quantification of liver iron concentration.

OBJECTIVE

To compare two MRI-based methods for liver iron quantification in children.

MATERIALS AND METHODS

64 studies on 48 children and young adults (age range 4-21 years) were examined by gradient recalled echo (GRE) R2* and spin-echo R2 MRI at 1.5T to evaluate liver iron concentration. Scatter plots and Bland-Altman difference plots were generated to display and assess the relationship between the methods.

RESULTS

With the protocols used in this investigation, Bland-Altman agreement between the methods is best when LIC is <20 mg/g dry tissue. Scatter plots show that all values with LIC <20 mg/g dry tissue fall within the 95% prediction limits.

CONCLUSION

Liver iron concentration as determined by the R2* and R2 MR methods is statistically comparable, with no statistical difference between these methods for LIC <20 mg/g.

Hepatic veno-occlusive disease may develop in secondary iron overloaded mice after allogeneic hematopoietic stem cell transplantation with total body irradiation

BACKGROUND

The outcome of hematopoietic stem cell transplantation (HSCT) is poor in patients with secondary iron overload (SIO). We evaluated the relationship between SIO and veno-occlusive disease (VOD) in an animal model with radiation for HSCT.

METHODS

We used a 6-week-old female BDF1 (H-2(b/d)) and a male C57/BL6 (H-2(b)) as recipient and donor, respectively. Recipient mice were injected intraperitoneally with 10 mg of iron dextran (cumulative doses of 50 mg, 100 mg, and 200 mg). All mice received total body irradiation for HSCT. We obtained peripheral blood for alanine transaminase (ALT) and liver for pathologic findings, lipid hyperoxide (LH) as reactive oxygen species (ROS), and liver iron content (LIC) on post-HSCT day 1 and day 7. The VOD score was assessed by pathologic findings.

RESULTS

ALT levels increased depending on cumulative iron dose, with significant differences between days 1 and 7 for mice loaded with 200 mg of iron (P<0.01). LH levels significantly increased in mice loaded with 200 mg of iron compared to those in other groups (P<0.01). For mice loaded with 100 mg of iron, the LH level depended on the radiation dose (P<0.01). There was a statistically significant relationship among ALT, LH, and LIC parameters (P<0.05). Pathologic scores for VOD correlated with LIC (P<0.01).

CONCLUSION

Livers with SIO showed high ROS levels depending on cumulative iron dose, and correlations with elevated liver enzyme and LIC. The pathologic score for VOD was associated with the LIC. Our results suggest that SIO may induce VOD after HSCT with irradiation.

Macrophage activation syndrome in a newborn infant born to a mother with autoimmune disease

Macrophage activation syndrome (MAS) is a complication of rheumatic disorders characterized by cytopenia, multiple organ dysfunction and coagulopathy associated with an inappropriate activation of macrophage. In neonatal lupus erythematosus, MAS is rare but fatal, requiring early diagnosis and treatment for optimal outcome. We report a case of MAS in a neonate born to a mother with autoimmune disease, improved by treatment with steroid, intravenous immunoglobulin and cyclosporine.

Impact of long term Fe³⁺ toxicity on expression of glutathione system in rat liver

The free radicals within the body, produced by metabolic activities or derived from environmental sources are relatively related to hepatoxicity. Since heavy metals including iron have the ability to produce free radicals, the liver glutathione system neutralizes them to protect cells against any damage. The objective of this study is to indicate the toxic effects of iron on the glutathione system at the enzymatic and molecular level. Thus, any possible correlation between enzymatic and molecular levels can be determined. According to our results, while mRNA expression of glutathione reductase (Gsr) and glutathione S-transferases (Gsta5) genes were not affected by long-term exposure to various concentrations of iron (Fe(3+)), transcription level of glutathione peroxidase (Gpx2) was influenced in the presence of toxic iron. Whereas the enzyme activites of GSR (GR), GPX and GST were significantly affected in rat liver.

Adrenal insufficiency is prevalent in HbE/β-thalassaemia paediatric patients irrespective of their clinical severity and transfusion requirement

OBJECTIVES

Transfusion dependency is known to cause endocrinopathies in patients with thalassaemia such as adrenal insufficiency, because transfusion-related iron overload is injurious to endocrine organs. Children with HbE/ß-thalassaemia vary greatly in red cell transfusion requirement and some are transfusion dependent (TD), whereas others are nontransfusion dependent (NTD). Because iron overload is thought to be the primary cause of adrenal insufficiency, TD children with HbE/ß-thalassaemia are considered likely candidates for the development of adrenal insufficiency, while the adrenal function of NTD children is generally considered to be normal. As yet, the prevalence of adrenal insufficiency among children with NTD HbE/β-thalassaemia is not known. The present study was performed to (i) assess the prevalence of adrenal insufficiency in children with both TD and NTD HbE/β-thalassaemia and to evaluate whether there is any difference in the prevalence of adrenal insufficiency between both groups and (ii) determine the type of adrenal insufficiency (primary or secondary).

METHODS

We investigated the prevalence of adrenal insufficiency among TD (n = 42) and NTD (n = 43) children with HbE/β-thalassaemia by assessing morning serum cortisol levels, and we distinguished between primary and secondary adrenal insufficiency by assessing the cortisol responses following the 1- and 250-μg ACTH stimulation tests.

RESULTS

The prevalence of adrenal insufficiency among TD and NTD children with HbE/β-thalassaemia was 50% and 53·5%, respectively. By using the 250-μg ACTH stimulation test, at least 39% and 23·5% were diagnosed with adrenal gland hypofunction in TD and NTD children, respectively.

CONCLUSION

This is the first study to show that adrenal insufficiency is common among all children with HbE/β-thalassaemia, irrespective of their transfusion history or requirement. Our findings have important implications for the clinical management of these children.

Iron overload and toxicity: implications for anesthesiologists

Conditions leading to iron overload range from rare hereditary disorders to more common medical conditions associated with chronic blood transfusions. Iron overload has deleterious effects on various vital organs (eg, liver, heart, and endocrine glands). Serum ferritin (in conjunction with transferrin saturation) is the most widely used test to evaluate iron burden and to screen for iron overload. The management plan should be adjusted to account for iron overload and potential consequences of liver, heart, and other organ involvement.

Ferritin in adult-onset still's disease: just a useful innocent bystander?

Background. Adult-Onset Still's Disease (AOSD) is an immune-mediated systemic disease with quotidian-spiking fever, rash, and inflammatory arthritis. Hyperferritinemia is a prominent feature, often used for screening. Methods. The key terms “ferritin” and “hyperferritinemia” were used to search PubMed and Medline and were cross-referenced with “Still's Disease.” Results. Hyperferritinemia, although nonspecific, is particularly prevalent in AOSD. While most clinicians associate ferritin with iron metabolism, this is mostly true for the H isoform and not for the L isoform that tends to increase dramatically in hyperferritenemia. In these situations, hyperferritinemia is not associated with iron metabolism and may even mask an underlying iron deficiency. We review, in systematic fashion, the current basic science and clinical literature regarding the regulation of ferritin and its use in the diagnosis and management of AOSD. Conclusion. Serum hyperferritinemia in AOSD has been described for 2 decades, although its mechanism has not yet been completely elucidated. Regulation by proinflammatory cytokines such as interleukin (IL)-1b, IL-6, IL-18, MCSF, and INF-α provides a link to the disease pathogenesis and may explain rapid resolution of hyperferritinemia after targeted treatment and inhibition of key cytokines.

The role of infection in the pathogenesis of vaso-occlusive crisis in patients with sickle cell disease

Sickle cell disease (SCD) is characterized by recurrent vaso-occlusive crisis (VOC). Patients with SCD have impaired immunity and are thus predispose to infections. The vast majority of SCD patients live in underdeveloped nations with high prevalence and transmission rates of infections. This makes the SCD patients prone to infections, which frequently precipitate VOC. We reviewed the role of infection in the pathogenesis of VOC, taking into consideration all potential mechanisms from previous studies and hypothetical perspectives. The potential mechanisms through which infections may lead to VOC involve several pathological changes including pneumonitis, pyrexia, acute phase reaction, hypercoagulability, neutrophilia, eosinophilia, thrombocytosis, bronchospasm, red cell cytopathic and membrane changes, auto-antibodies mediated red cell agglutination and opsonization, diarrhoea and vomiting, which may act singly or in concert to cause red cell sickling. These changes can induce sickling directly or indirectly through their adverse effects on Hb oxygenation and polymerization, hydration, blood viscosity, red cell metabolism, procoagulant activation, intercellular adherence and aggregation, culminating in VOC. There is therefore the need to ameliorate the burden of infection on SCD through immunization, prophylactic and therapeutic use of antimicrobials, barrier protection and vector control in communities with high prevalence of SCD.

Iron overload and allogeneic hematopoietic stem-cell transplantation

Iron overload is frequently observed in patients with hematologic diseases before and after allogeneic stem-cell transplantation because they usually receive multiple red blood cell transfusions. Elevated pretransplant serum ferritin levels, which are widely used as indicators of body iron status, are significantly associated with a lower overall survival rate and a higher incidence of treatment-related complications; for example, infections and hepatic veno-occlusive disease. As serum ferritin levels are affected, not only by iron loading but also by inflammation, imaging techniques to quantify tissue iron levels have been developed, for example, quantitative MRI using the transverse magnetic relaxation rate, and superconducting quantum interference devices. Iron chelators, such as deferasirox, a new oral iron-chelating agent, reduce iron load in transfusion-dependent patients. Iron-chelating therapy before and/or after transplantation is a promising strategy to improve the clinical outcomes of transplant patients with iron overload. However, further research is needed to prove the direct relationship between iron overload and adverse outcomes, as well as to determine the effects of treatment for iron overload on outcomes of allogeneic stem-cell transplantation.

Donor haptoglobin phenotype determines outcome following liver transplantation

Haptoglobin (Hp) is a polymorphic plasma protein with multiple functions defined by three major phenotypes (Hp 1-1, Hp 2-1, and Hp 2-2). In this article, the effects of the donor Hp phenotype (determined by starch gel electrophoresis) on the outcome and the iron status after liver transplantation were investigated. A total of 450 liver transplant patients were enrolled in this study with a median follow-up of 37 months. Kaplan-Meier and Cox regression survival analyses showed a significantly worse graft survival for liver transplantation cases with an Hp 2-2 donor phenotype, which was associated with an increased mortality rate in this group. In male patients, the Hp 2-2 phenotype was associated with higher serum ferritin concentrations, which may be linked to the significantly increased likelihood of infectious complications in this phenotype. Liver transplant patients with Hp 1-1 and Hp 2-1 grafts had a better outcome probability than recipients of an Hp 2-2 graft, which may be explained by differences in iron metabolism induced by the Hp genotype of the graft.

Insidious iron burden in pediatric patients with acute lymphoblastic leukemia

BACKGROUND

A significant iron burden may occur after only 10 blood transfusions in patients with hematologic disorders. Children with acute lymphoblastic leukemia (ALL) routinely receive blood transfusions during therapy, although few studies to date have quantified transfusion-related iron burden in these patients. This study quantifies the transfused blood volume and resultant iron load in a large cohort of pediatric patients with ALL, and evaluates risk factors that may impact transfusion volume.

METHODS

This single institution retrospective study evaluated 107 patients who completed therapy for ALL between July 1995 and March 2007. Age, weight, and hemoglobin at presentation, ALL risk category, leukemia cell type, and volume of blood transfusions were collected from medical records.

RESULTS

Patients received an average of 115 ml/kg of blood (77 mg/kg iron) during treatment. There was a significant association between the volume of packed red blood cells and ALL risk category. Patients with standard-risk disease received 90 ml/kg (60 mg/kg iron), patients with high-risk disease 196 ml/kg (131 mg/kg iron) and patients with T-cell disease 114 ml/kg (76 mg/kg iron). There was no correlation between age or hemoglobin at presentation with amount of blood received.

CONCLUSIONS

Patients with ALL often receive a substantial amount of iron during therapy, with patients with high-risk disease receiving the greatest load. As iron overload has an overlapping toxicity profile with chemotherapy and is treatable, screening for increased iron burden and iron-related morbidities should be considered during long-term follow-up of patients with ALL, particularly in those with high-risk ALL.

The association of infection and clinical severity in sickle cell anaemia patients

Sickle cell anaemia (SCA) patients have a high risk of infection. We retrospectively investigated the prevalence of infection among SCA patients from Bahia, Brazil. A total of 1415 SCA patients were studied between 1995 and 2009: 190 (13.4%) had hepatitis C virus (HCV), 67 (4.7%) had human T-lymphotropic virus type I (HTLV-I), 44 (3.1%) had hepatitis B virus (HBV), 40 (2.8%) had Chagas' disease, 11 (0.8%) had human immunodeficiency virus (HIV), and 5 (0.4%) had syphilis. Patients with HCV infection had a higher risk of hospitalisation (OR=1.52, 95% Cl: 1.07-2.17, P=0.020), bone disorders (OR=1.94, 95% Cl: 1.15-3.27, P=0.011), stroke (OR=2.17, 95% Cl: 1.12-4.14, P=0.017), painful crisis (OR=1.61, 95% Cl: 1.17-2.22, P=0.004) and leg ulcers (OR=1.61, 95% Cl: 1.04-3.03, P=0.031). Patients with HBV infection had a higher risk for bone disorders (OR=4.90, 95% Cl: 2.08-11.54, P<.010), stroke (OR=3.01, 95% Cl: 1.29-6.04, P=0.007), painful crisis (OR=3.51, 95% Cl: 1.62-7.63, P<0.001), acute chest syndrome (ACS) (OR=2.66, 95% Cl: 1.34-5.28, P=0.004), leg ulcers (OR=6.60, 95% Cl: 3.37-12.91, P<.001) and vaso-occlusive crisis (OR=6.34, 95% Cl: 1.96-20.66, P<0.001). Patients with HTLV-I infection had a high risk for bone disorders (OR=2.94, 95% Cl: 1.28-6.74, P=0.011), respiratory failure (OR=2.66, 95% Cl: 1.26-5.51, P=0.012), leg ulcers (OR=3.27, 95% Cl: 1.69-6.11, P<.001), painful crisis (OR=1.82, 95% Cl: 1.07-3.13, P=0.025) and ACS (OR=1.85, 95% Cl: 1.10-3.41, P<.047). SCA patients with HCV infection had increased triglycerides and low-density lipoprotein cholesterol (P=0.036; P=0.027), iron serum (P=0.016) and ferritin (P=0.007). These results reveal important roles for these infections in SCA patients' clinical outcomes, and studies are warranted to determine the mechanisms utilised by these agents and their involvement in disease severity.

Disorders of iron metabolism. Part II: iron deficiency and iron overload

Main disorders of iron metabolism

Increased iron requirements, limited external supply, and increased blood loss may lead to iron deficiency (ID) and iron deficiency anaemia. In chronic inflammation, the excess of hepcidin decreases iron absorption and prevents iron recycling, resulting in hypoferraemia and iron restricted erythropoiesis, despite normal iron stores (functional iron deficiency), and finally anaemia of chronic disease (ACD), which can evolve to ACD plus true ID (ACD+ID). In contrast, low hepcidin expression may lead to hereditary haemochromatosis (HH type I, mutations of the HFE gene) and type II (mutations of the hemojuvelin and hepcidin genes). Mutations of transferrin receptor 2 lead to HH type III, whereas those of the ferroportin gene lead to HH type IV. All these syndromes are characterised by iron overload. As transferrin becomes saturated in iron overload states, non-transferrin bound iron appears. Part of this iron is highly reactive (labile plasma iron), inducing free radical formation. Free radicals are responsible for the parenchymal cell injury associated with iron overload syndromes.

Role of laboratory testing in diagnosis

In iron deficiency status, laboratory tests may provide evidence of iron depletion in the body or reflect iron deficient red cell production. Increased transferrin saturation and/or ferritin levels are the main cues for further investigation of iron overload. The appropriate combination of different laboratory tests with an integrated algorithm will help to establish a correct diagnosis of iron overload, iron deficiency and anaemia.

Review of treatment options

Indications, advantages and side effects of the different options for treating iron overload (phlebotomy and iron chelators) and iron deficiency (oral or intravenous iron formulations) will be discussed.