An Internal Promoter Drives the Expression of a Truncated Form of CCC1 Capable of Protecting Yeast from Iron Toxicity

In yeast, iron storage and detoxification depend on the Ccc1 transporter that mediates iron accumulation in vacuoles. While deletion of the CCC1 gene renders cells unable to survive under iron overload conditions, the deletion of its previously identified regulators only partially affects survival, indicating that the mechanisms controlling iron storage and detoxification in yeast are still far from well understood. This work reveals that CCC1 is equipped with a complex transcriptional structure comprising several regulatory regions. One of these is located inside the coding sequence of the gene and drives the expression of a short transcript encoding an N-terminally truncated protein, designated as s-Ccc1. s-Ccc1, though less efficiently than Ccc1, is able to promote metal accumulation in the vacuole, protecting cells against iron toxicity. While the expression of the s-Ccc1 appears to be repressed in the normal genomic context, our current data clearly demonstrates that it is functional and has the capacity to play a role under iron overload conditions.

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Lipidomics reveals perturbations in the liver lipid profile of iron overloaded mice

Metallomics ◽

10.1093/mtomcs/mfab057 ◽

2021 ◽

Author(s):

Haoxuan Ding ◽

Qian Zhang ◽

Xiaonan Yu ◽

Lingjun Chen ◽

Zhonghang Wang ◽

...

Keyword(s):

Iron Overload ◽

Iron Status ◽

Liver Lipid ◽

Density Lipoprotein ◽

Global Scale ◽

The Body ◽

Control Group ◽

Sod Activity ◽

Liver Iron ◽

Iron Storage

Abstract Iron overload is an important contributor to disease. The liver, the major site of iron storage in the body, is a key organ impacted by iron overload. While several studies have reported perturbations in liver lipids in iron overload, it is not clear, on a global scale, how individual liver lipid ions are altered. Here, we used lipidomics to study the changes in hepatic lipid ions in iron-overloaded mice. Iron overload was induced by daily intraperitoneal injections of 100mg/kg body weight iron dextran for one week. Iron overload was verified by serum markers of iron status, liver iron quantitation, and Perls’ stain. Compared with the control group, the serum of iron-overload mice exhibited low levels of urea nitrogen and high-density lipoprotein (HDL), and high concentrations of total bile acid, low-density lipoprotein (LDL), aspartate aminotransferase (AST), alanine aminotransferase (ALT), and lactate dehydrogenase (LDH), suggestive of liver injury. Moreover, iron overload disrupted liver morphology, induced reactive oxygen species (ROS) production, reduced superoxide dismutase (SOD) activity, caused lipid peroxidation, and led to DNA fragmentation. Iron overload altered the overall composition of lipid ions in the liver, with significant changes in over 100 unique lipid ions. Notably, iron overload selectively increased the overall abundance of glycerolipids and changed the composition of glycerophospholipids and sphingolipids. This study, one of the first to report iron-overload induced lipid alterations on a global lipidomics scale, provides early insight into lipid ions that may be involved in iron overload-induced pathology.

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Possible Protective Role of Deferoxamine in Ameliorating Osteoporosis in a Rat Model of Liver Cirrhosis via Iron Metabolism Regulation

QJM ◽

10.1093/qjmed/hcab114.006 ◽

2021 ◽

Vol 114 (Supplement_1) ◽

Author(s):

Shereen Helmy ◽

Doaa I Mohamed ◽

Wesam Elbakly ◽

Lobna F Abd Elaziz ◽

Eman Khairy ◽

...

Keyword(s):

Liver Cirrhosis ◽

Iron Overload ◽

Rat Model ◽

Bone Fractures ◽

Bone Mineralization ◽

Treated Group ◽

Disease Etiology ◽

Iron Storage ◽

Metabolism Regulation ◽

Hepatic Diseases

Abstract Background Liver cirrhosis is considered the terminal stage of many hepatic diseases of different etiologies. Liver cirrhosis was associated with increased incidence rates of some extrahepatic manifestations such as osteoporosis. Regardless of the liver disease etiology, the presence of cirrhosis implies a twofold risk of bone fractures higher than non-cirrhotic patients. The liver is the main storage depot for iron and is the primary organ that is responsible for clearing excess iron in conditions of iron overload. When the iron storage and antioxidant capacity of the liver is overwhelmed, iron overload can lead to marked oxidantmediated liver and bone injury and iron overload was a risk factor for osteoporosis via affecting osteoblast survival. Aim of the work to examine the possible protective effect of Deferoxamine (DFO) on liver cirrhosis rat model induced osteoporosis. Material and Method rats was divided into 4 groups Animal Groups: Naïve control, DFO-treated group, TAA-treated group received Thioacetamide (TAA) ip (200 mg/kg/rat) twice weekly for 12 weeks, TAA+DFO treated group received TAA intra-peritoneal in addition to DFO intraperitoneal injections (300 mg/kg/3 times/week, for the last 4 weeks of TAA injections. Results and Conclusion Deferoxamine produced significant improvement in bone mineralization alongside its significant effect on liver function test in a rat model of liver cirrhosis induced osteoporosis.

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Impact of magnetic resonance imaging on the diagnosis of abdominal complications of paroxysmal nocturnal hemoglobinuria

Blood ◽

10.1182/blood.v85.11.3283.bloodjournal85113283 ◽

1995 ◽

Vol 85 (11) ◽

pp. 3283-3288 ◽

Cited By ~ 22

Author(s):

D Mathieu ◽

A Rahmouni ◽

P Villeneuve ◽

MC Anglade ◽

H Rochant ◽

...

Keyword(s):

Magnetic Resonance ◽

Mr Imaging ◽

Iron Overload ◽

Signal Intensity ◽

Paroxysmal Nocturnal Hemoglobinuria ◽

Renal Cortex ◽

Iron Storage ◽

Abdominal Complications ◽

Vein Thrombosis ◽

Hepatic Vein Obstruction

Magnetic resonance (MR) imaging is a method of choice for assessing vascular patency and parenchymal iron overload. During the course of paroxysmal nocturnal hemoglobinuria (PNH), it is clinically relevant to differentiate abdominal vein thrombosis from hemolytic attacks. Furthermore, the study of the parenchymal MR signal intensity adds informations about the iron storage in kidneys, liver, and spleen. Twelve PNH patients had 14 MR examinations of the abdomen with spin-echo T1- and T2-weighted images and flow-sensitive gradient echo images. Vessels patency and parenchymal signal abnormalities--either focal or diffuse--were assessed. MR imaging showed acute complications including hepatic vein obstruction in five patients, portal vein thrombosis in two patients, splenic infarct in one patient. In one patient treated with androgens, hepatocellular adenomas were shown. Parenchymal iron overload was present in the renal cortex of eleven patients with previous hemolytic attacks. On the first MR study of the remaining patient with an acute abdominal pain showing PNH, no iron overload was present in the renal cortex. Follow-up MR imaging showed the onset of renal cortex iron overload related to multiple hemolytic attacks. Despite the fact that all our patients were transfused, normal signal intensity of both liver and spleen was observed in three of them. MR imaging is particularly helpful for the diagnosis of abdominal complications of PNH.

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Iron Stores in Patients with Myelodysplasia and Aplastic Anemia.

Blood ◽

10.1182/blood.v108.11.3726.3726 ◽

2006 ◽

Vol 108 (11) ◽

pp. 3726-3726

Author(s):

Peter Nielsen ◽

Tim H. Bruemmendorf ◽

Regine Grosse ◽

Rainer Engelhardt ◽

Nicolaus Kroeger ◽

...

Keyword(s):

Risk Factor ◽

Iron Overload ◽

Aplastic Anemia ◽

Myelodysplastic Syndromes ◽

Iron Concentration ◽

Dry Weight ◽

Iron Toxicity ◽

Intervention Threshold ◽

Liver Iron Concentration ◽

Liver Iron

Abstract Patients with myelodysplastic syndromes (MDS), osteomyelofibrosis (OMF), or severe aplastic anemia (SAA) suffer from ineffective erythropoiesis due to pancytopenia, which is treated with red blood cell transfusion leading to iron overload. Especially in low-risk patients with mean survival times of > 5 years, potentially toxic levels of liver iron concentration (LIC) can be reached. We hypothesize that the higher morbidity seen in transfused patients may be influenced by iron toxicity. Following a meeting in Nagasaki 2005, a consensus statement on iron overload in myelodysplastic syndromes has been published, however, there is still no common agreement about the initiation of chelation treatment in MDS patients. In the present study, a total of 67 transfused patients with MDS (n = 20, age: 17 – 75 y), OMF (n = 4, age: 48 – 68 y), SAA (n = 43, age: 5 – 64 y) were measured by SQUID biomagnetic liver susceptometry (BLS) and their liver and spleen volumes were scanned by ultrasound at the Hamburg biosusceptometer. Less than 50 % were treated with DFO. LIC (μg/g-liver wet weight, conversion factor of about 6 for μg/g-dry weight) and volume data were retrospectively analyzed in comparison to ferritin values. Additionally, 15 patients (age: 8 – 55 y) between 1 and 78 months after hematopoietic cell transplantation (HCT) were measured and analyzed. LIC values ranged from 149 to 8404 with a median value of 2705 μg/g-liver, while serum ferritin (SF) concentrations were between 500 and 10396 μg/l with a median ratio of SF/LIC = 0.9 [(μg/l)/(μg/g-liver)] (range: 0.4 to 5.2). The Spearman rank correlation between SF and LIC was found to be highly significant (RS = 0.80, p < 0.0001), however, prediction by the linear regression LIC = (0.83± 0.08)·SF was poor (R2 = 0.5) as found also in other iron overload diseases. Although iron toxicity is a long-term risk factor, progression of hepatic fibrosis has been observed for LIC > 16 mg/g dry weight or 2667 μg/g-liver (Angelucci et al. Blood2002; 100:17–21) within 60 months and significant cardiac iron levels have been observed for LIC > 350 μmol/g or 3258 μg/g-liver (Jensen et al. Blood2003; 101:4632-9). The Angelucci threshold of hepatic fibrosis progression was exceeded by 51 % of our patients, while 39 % were exceeding the Jensen threshold of potential risk of cardiac iron toxicity. The total body iron burden is even higher as more than 50 % of the patients had hepatomegaly (median liver enlargement factor 1.2 of normal). A liver iron concentration of about 3000 μg/g-liver or 18 mg/g-dry weight has to be seen as latest intervention threshold for chelation treatment as MDS patients are affected by more than one risk factor. A more secure intervention threshold would be a LIC of 1000 μg/g-liver or 4 – 6 mg/g-dry weight, corresponding with a ferritin level of 900 μg/l for transfused MDS patients. Such a LIC value is not exceeded by most subjects with heterozygous HFE-associated hemochromatosis and is well tolerated without treatment during life-time. Non-invasive liver iron quantification offers a more reliable information on the individual range of iron loading in MDS which is also important for a more rational indication for a chelation treatment in a given patient.

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Safety and Efficacy of High Dose Intravenous Desferoxamine for Reduction of Iron Overload Due to Chronic Transfusion in Sickle Cell Patients.

Blood ◽

10.1182/blood.v112.11.1430.1430 ◽

2008 ◽

Vol 112 (11) ◽

pp. 1430-1430

Author(s):

Ram Kalpatthi ◽

Brittany Peters ◽

David Holloman ◽

Elizabeth Rackoffe ◽

Deborah Disco ◽

...

Keyword(s):

Serum Creatinine ◽

Iron Overload ◽

Sickle Cell ◽

Serum Ferritin ◽

Liver Tissue ◽

Iron Concentration ◽

P Value ◽

High Dose ◽

Liver Iron ◽

Iron Storage

Abstract Background: Patients with sickle cell disease (SCD) receiving chronic blood transfusions are at risk of developing iron overload and organ toxicity. Chelation therapy with either subcutaneous (SQ) desferoxamine (DFO) or oral deferasirox is effective in preventing and reducing iron overload but poses significant challenges with patient compliance. Intravenous (IV) infusions of high dose DFO (HDD) have been utilized in non compliant patients with heavy iron overload in small case series. We review our experience of high dose IV DFO in a large cohort of SCD patients with significant iron overload who are non compliant with SQ DFO. Methods: The medical records of SCD patients who received HDD in our center between 1993 and 2004 were reviewed. All of them were on chronic transfusion, had significant iron overload defined by serum ferritin > 1500 and/or liver iron concentration (LIC) more than 10 μg/g of liver tissue and were non-compliant with SQ DFO. All patients underwent annual ophthalmologic, hearing, pulmonary and cardiac evaluation. Demographic data, treatment details, serum ferritin levels, liver iron concentration (LIC), liver enzymes, renal function tests, audiogram and other relevant clinical data were collected. Results: There were 27 patients (19 males, 8 females), 19 patients were on transfusion for history of cerebrovascular accident, 5 for abnormal transcranial Doppler flow velocity, 2 for transient ischemic attack and one for recurrent pain crises. All continued to receive packed red blood cell transfusions aimed to keep HbS levels below 30 or 50% during this time. They were treated in-hospital with DFO 15 mg/kg/hr IV for 48 hrs every 2 weeks (20 patients), 3 weeks (4 patients) and 4 weeks (3 patients). The mean age at start of high dose regimen was 14.6 years (range 9–27 years). The mean duration of HDD treatment was 8.9 months (range 3–49 months). Fourteen patients had LIC determined by liver biopsy. Significant reductions in LIC were observed after HD (table I). This was more pronounced in patients who had higher LIC and received at least 6 months of HDD. Histological examination of liver biopsies revealed a decrease in the grade of liver iron storage. Four patients had portal triaditis initially which resolved after starting HDD therapy. Also there was significant improvement in liver enzymes (ALT, AST) after HDD. There was a trend in decreasing ferritin levels after HDD but this did not achieve statistical significance. All patients tolerated HDD without any major reactions. No audiologic or ophthalmologic toxicity or acute or chronic pulmonary complications were observed. Blood urea nitrogen remained normal in all patients after HDD but there was mild increase in serum creatinine. One patient had high serum creatinine (1.2 mg/dL) after two doses HDD. This patient had focal segmental glomeurosclerosis which was most probably the cause for the rise in creatinine. There was no significant increase in serum creatinine in our series when this patient was excluded. Conclusions: In our cohort of SCD patients we observed a significant decrease in liver iron burden with high dose IV DFO. Our patients tolerated the therapy well without any major toxicity. This regimen is safe and may be an option for poorly compliant patients with significant iron overload. In addition, combination of this regimen with oral iron chelators may be of benefit to patients with significant iron overload and organ dysfunction. Table 1: Laboratory characteristics of sickle cell patients before and after high dose IV DFO Parameter No. of Patients Mean (SD) prior to HDD Mean (SD)after HDD p Value* * Changes in mean levels analyzed using two-tailed Paired T Test with significant p value ≤ 0.05. SD – Standard deviation + See text Liver iron (μg/g of liver tissue ) 14 16864 (10903) 12681 (8298) 0.04 Liver iron min of 6 months of HDD (μg/g of liver tissue ) 8 18677 (8319) 9362 (4521) 0.01 Liver iron >10 mg & minimum 6 months of HDD (μg/g of liver tissue) 7 21181 (7054) 10092 (4443) 0.01 Grade of liver iron storage 14 3.57 (0.9) 3.07 (1) 0.05 Serum Ferritin (ng/mL) 27 3842 (2619) 3238 (1780) 0.06 Serum AST (IU/L) 27 54.1 (27.2) 44.6 (17.6) 0.04 Serum ALT (IU/L) 27 39.2 (36) 27.5 (14.2) 0.01 Blood urea nitrogen (mg/dL) 27 8.9 (2.9) 9.5 (4.3) 0.20 Serum Creatinine (mg/dL)+ 26 0.50 (0.1) 0.55 (0.2) 0.07

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Pituitary Iron and Volume in Transfusional Iron Overload.

Blood ◽

10.1182/blood.v114.22.2017.2017 ◽

2009 ◽

Vol 114 (22) ◽

pp. 2017-2017 ◽

Cited By ~ 1

Author(s):

Leila J Noetzli ◽

Ashok Panigrahy ◽

Mehrdad Joukar ◽

Aleya Hyderi ◽

Steven D Mittelman ◽

...

Keyword(s):

Iron Overload ◽

Anterior Pituitary ◽

Research Funding ◽

Hypogonadotropic Hypogonadism ◽

Iron Concentration ◽

Iron Toxicity ◽

Iron Deposition ◽

Delayed Puberty ◽

Iron Loading ◽

Z Score

Abstract Abstract 2017 Poster Board I-1039 Introduction: Hypogonadotropic hypogonadism (HH) is the most common endocrine problem in chronically transfused patients. Unfortunately, gonadotrophe iron toxicity is not readily detectable until puberty and stimulation tests can be difficult to interpret in adolescents. MRI can image preclinical pituitary iron deposition, similar to its use in the heart, liver and pancreas. Increased pituitary R2, a surrogate for iron, and decreased pituitary volume have both been shown to predict clinical and biochemical HH in iron overloaded adults 1,2. However, data regarding pituitary iron deposition and toxicity is lacking in younger patients with iron overload. We present baseline results from a two year observational trial of changes in pituitary R2 and volume in response to deferasirox therapy in patients with transfusional siderosis. Methods: We studied 22 chronically-transfused patients with Thalassemia Major and 2 patients with Diamond Blackfan Anemia. The average age was 13.1 ± 5.2 years (range: 3.7-23.6 years). All studies were performed on a 1.5 T Philips Achieva. Anterior pituitary R2 was assessed in the sagittal and coronal planes using multiple spin echoes from 15 to 120 ms. Pituitary volume was assessed using a 3D spoiled gradient echo sequence with 1 mm3 isotropic voxels. Pituitary R2 was calculated by pixelwise monoexponential fit, with median values used to represent the overall gland R2; boundaries were confirmed by a board-certified neuroradiologist. Normative data for pituitary iron and volume was drawn from another study in 49 normal volunteers. MRI estimates of hepatic iron concentration (HIC), cardiac iron (T2*), and pancreatic iron (R2*) were obtained as clinical standard of care. All statistics were performed using JMP5.1 (SAS, Cary, NC). Results: Patients were mild to moderately iron loaded, with a HIC of 10.2 ± 12.0 mg/g dry wt (median 4.5 mg/g, nl < 1.5 mg/g), cardiac T2* of 29.4 ± 9.2 ms (median 31.5 ms, nl > 20ms), and pancreas R2* of 136 ± 156 Hz (median 73 Hz, nl < 27 Hz). Fourteen patients were below the 10th percentile for height including 7 below the 5th percentile. One patient had been diagnosed with delayed puberty and was on estrogen replacement. Pituitary R2 was elevated in 13/24 patients, beginning in the first decade of life and worsening in patients older than 13 years of age (Figure 1, left). Mean Z-score was 3.2 ± 3.7 (median 2.5, range -0.5 to12.8). Pituitary R2 was correlated with HIC (r2=0.68) and pancreatic R2* (r2=0.40), but not cardiac R2*. Area under the receiver operator characteristic curve was 0.76 for both HIC and pancreatic iron for the prediction of pituitary iron loading. Anterior pituitary volumes were low-normal in the first decade of life but were below the 1st percentile in 4/16 patients older than 13 years of age (Figure 1, right); all 4 patients with severe pituitary shrinkage had significant pituitary iron loading (Z-scores ranging from 2.8 to 12.8). The patient having documented HH had an iron Z-score of 12.8 and a volume Z-score of –5.0. Discussion: HH remains one of the most difficult endocrinopathies to recognize and prevent in transfusional siderosis. The present data demonstrate that iron accumulation occurs early in these patients and worsens dramatically in the second decade of life. Pituitary R2 was closely correlated with liver and pancreatic iron suggesting more rapid iron transport kinetics than for the heart. The low-normal pituitary volumes in childhood may reflect ethnic mismatches between the control and study populations, early iron toxicity, or hypothalamic dysfunction from increased erythropoiesis and metabolic demand. However, severe pituitary volume loss was limited to the second decade of life and associated with markedly increased pituitary iron (R2). Thus, there appears to be a broad, preclinical window to reduce pituitary toxicity. MRI screening of pituitary size and iron concentration needs to be expanded, clinically, to explore this hypothesis and hopefully prevent the significant physiological and psychological sequelae associated with hypogonadism. Disclosures: Coates: Novartis: Consultancy, Honoraria, Research Funding, Speakers Bureau. Wood:Novartis: Research Funding.

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Target TMPRSS6 for the Treatment of Hereditary Hemochromatosis

Blood ◽

10.1182/blood.v118.21.1047.1047 ◽

2011 ◽

Vol 118 (21) ◽

pp. 1047-1047

Author(s):

Sheri Booten ◽

Daniel Knox ◽

Luis Alvarado ◽

Shuling Guo ◽

Brett P. Monia

Keyword(s):

Iron Overload ◽

Genetic Disorder ◽

Hereditary Hemochromatosis ◽

Genetic Defect ◽

Transferrin Saturation ◽

Common Mutation ◽

C282y Mutation ◽

Iron Storage ◽

Hepcidin Expression ◽

Iron Deficient

Abstract Abstract 1047 Hereditary hemochromatosis (HH) is a genetic disorder in which hyperabsorption of dietary iron leads to accumulation of iron in multiple tissues including liver and heart. A common clinical manifestation in HH patients is cirrhosis and hepatocellular carcinoma as a result of iron-mediated injury in liver. The most prevalent genetic defect for HH is the failure to up-regulate hepcidin, a peptide hormone that inhibits the absorption of iron in duodenum and the release of iron from intracellular iron storage such as macrophages. Mutations in a number of genes have been identified as the cause for HH, including hepcidin itself. However, the most common mutation is C282Y mutation in HFE, which is a positive regulator for hepcidin expression. C282Y mutation represents about 85% of the HH population. HFE C282Y HH is an autosomal recessive disease with a ∼50% penetrance. Currently, the only treatment available for iron overload is phlebotomy which will continue throughout the patient's life. Hepcidin is mainly expressed and secreted by the liver and its expression is regulated predominantly at the transcription level. TMPRSS6, a transmembrane serine protease mutated in iron-refractory, iron-deficient anemia, is a major suppressor for hepcidin expression. It's been demonstrated that hepcidin expression is significantly elevated in Tmprss6−/− mice and reduction of TMPRSS6 in Hfe−/− mice could ameliorate the iron overload phenotype (Du et al. Science 2008; Folgueras et al. Blood 2008; Finberg KE et al., Blood, 2011). Using second generation antisense technology, we identified antisense oligonucleotides (ASOs) targeting mouse TMPRSS6 for the treatment of HH. These compounds were first identified through in vitro screens in mouse primary hepatocytes. After 4 weeks of treatment in C57BL/6 mice on normal chow, we observed an 80% to 90% reduction of liver TMPRSS6 mRNA with a subsequent 2–3 fold induction of liver hepcidin mRNA. Serum iron and transferrin saturation levels were reduced by ∼50%. These ASOs are currently being evaluated in a diet-induced iron overload model and an Hfe−/− iron overload model. Our preliminary results demonstrate that targeting TMPRSS6 is a viable approach for the treatment of hereditary hemochromatosis and possibly other iron-loading diseases associated with suppressed hepcidin levels. Disclosures: Booten: Isis Pharmaceuticals: Employment. Knox:Isis Pharmaceuticals: Summer Intern. Alvarado:Isis Pharmaceuticals: Employment. Guo:Isis Pharmaceuticals: Employment. Monia:Isis Pharmaceuticals: Employment.

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Efficacy and Safety of Amlodipine in Preventing Myocardial Iron Overload in Patients with Transfusion-Dependent Thalassemia Major : A Systematic Review and Meta-Analysis

Blood ◽

10.1182/blood-2020-137713 ◽

2020 ◽

Vol 136 (Supplement 1) ◽

pp. 48-49

Author(s):

Richi Kashyap ◽

Muhammad Ashar Ali ◽

Saad Ullah Malik ◽

Farhan Khalid ◽

Ali Jaan ◽

...

Keyword(s):

Adverse Effects ◽

Iron Overload ◽

Meta Analysis ◽

Iron Concentration ◽

Iron Chelation ◽

Thalassemia Major ◽

Iron Toxicity ◽

Control Group ◽

P Value ◽

Myocardial Iron

Background: Patients diagnosed with thalassemia major who are transfusion dependant, have iron accumulation leading to iron toxicity and severe impairment in organs like heart, liver and endocrine organs which are highly sensitive to iron toxicity. This makes iron chelation therapy imperative for these patients. Half of the deaths resulting from iron toxicity related complications are attributed to cardiac complications. Iron chelation therapies have not been completely successful to prevent iron toxicity related complications like arrhythmia, cardiomyopathy and heart failure. Higher doses of iron chelation therapies have been associated with various side effects. Studies have shown L-type calcium channel blocker might be able to reduce iron uptake by myocardium. The aim of this meta-analysis is to assess the efficacy and safety of amlodipine to reduce myocardial iron concentration (MIC). Methods: We used PICO framework to do a systematic literature search using four database PubMed, Cochrane, Embase, and Web of Science using keywords, "Thalassemia" AND "Amlodipine" from the inception till July 2020. The initial search showed 90 articles out of which, six randomized clinical trials (RCT) (N= 226) were selected after exclusion of case reports, case series, preclinical trials, review articles, meta-analysis, and trials not providing any information about preventing iron overload in patients with transfusion dependent thalassemia. We extracted the data for myocardial iron concentration (MIC), myocardial T2, ferritin, hepatic iron/liver iron concentration (LIC), liver T2, left ventricular ejection fraction, response rate and adverse effects. DerSimonian-Laird random effects model was used to derive mean differences along with their 95% confidence interval (CI) using comprehensive meta-analysis version 3.0. Results: In six RCT, 96 patients were tested in experimental group and 97 in control group. In five RCT total number of male participants were 45 in experimental group and 54 in control group. 33 patients had splenectomy in experimental group and 41 in control group. The age range was 8 years to 31 years. The myocardial T2 score increased in amlodipine group compared to standard chelation group with significant mean difference estimated to be -0.62 (95% CI: -0.95-0.29, p-value: <0.001) in favor of amlodipine in meta-analysis of the four trials (Fig 1.). Statistically significant reduction in myocardial iron was seen in two trials on adding amlodipine to standard chelation therapy (N=55) (Table 1.) (Khaled et al and Fernandes et al). Significant difference was reported in liver T2 score and LIC at the end of six months between amlodipine and control group by Khaled et al. But, there was no statistically significant mean difference in serum ferritin and in liver MRI T2 between amlodipine group and control group with mean difference of -1143 (95% CI: -2410 to 124, p-value = 0.07) and -0.06 (95% CI: -0.463 to 0.338, p-value = 0.76) in meta-analysis of four and two trials respectively (Fig 2. And Fig 3.). El-Haggar et al compared amlodipine with spirulina and statistically significant improvement in myocardial T2 and NT-proBNP level was seen in both groups. Spirulina group also showed significant reduction in serum ferritin, which showed spirulina could also help reduce iron overload. Only mild adverse effects were reported by trials (Table 2.). No cases of severe hypotension, palpitation or any other serious adverse effects were seen in the amlodipine group. Conclusion: This systematic review and meta-analysis suggests that addition of amlodipine 2.5-5 mg/day to standard chelation therapy with monitoring for potential adverse effects, could benefit patients with thalassemia major by reducing cardiac iron overload and thus improve survival and quality of life. Future studies are required to study the role of amlodipine in reducing iron overload in endocrine organs that also absorb iron through voltage-gated channels, particularly considering the close association of cardiac siderosis with endocrine complications and the correlation of pancreas and MICs. Disclosures Anwer: Incyte, Seattle Genetics, Acetylon Pharmaceuticals, AbbVie Pharma, Astellas Pharma, Celegene, Millennium Pharmaceuticals.: Honoraria, Research Funding, Speakers Bureau.

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Management of Iron Overload in Beta-Thalassemia Patients: Clinical Practice Update Based on Case Series

International Journal of Molecular Sciences ◽

10.3390/ijms21228771 ◽

2020 ◽

Vol 21 (22) ◽

pp. 8771

Author(s):

Valeria Maria Pinto ◽

Gian Luca Forni

Keyword(s):

Iron Overload ◽

Malignant Transformation ◽

Chelation Therapy ◽

Prolonged Exposure ◽

Case Series ◽

Iron Toxicity ◽

Beta Thalassemia ◽

Human Organism ◽

Noninvasive Methods ◽

Toxic Agent

Thalassemia syndromes are characterized by the inability to produce normal hemoglobin. Ineffective erythropoiesis and red cell transfusions are sources of excess iron that the human organism is unable to remove. Iron that is not saturated by transferrin is a toxic agent that, in transfusion-dependent patients, leads to death from iron-induced cardiomyopathy in the second decade of life. The availability of effective iron chelators, advances in the understanding of the mechanism of iron toxicity and overloading, and the availability of noninvasive methods to monitor iron loading and unloading in the liver, heart, and pancreas have all significantly increased the survival of patients with thalassemia. Prolonged exposure to iron toxicity is involved in the development of endocrinopathy, osteoporosis, cirrhosis, renal failure, and malignant transformation. Now that survival has been dramatically improved, the challenge of iron chelation therapy is to prevent complications. The time has come to consider that the primary goal of chelation therapy is to avoid 24-h exposure to toxic iron and maintain body iron levels within the normal range, avoiding possible chelation-related damage. It is very important to minimize irreversible organ damage to prevent malignant transformation before complications set in and make patients ineligible for current and future curative therapies. In this clinical case-based review, we highlight particular aspects of the management of iron overload in patients with beta-thalassemia syndromes, focusing on our own experience in treating such patients. We review the pathophysiology of iron overload and the different ways to assess, quantify, and monitor it. We also discuss chelation strategies that can be used with currently available chelators, balancing the need to keep non-transferrin-bound iron levels to a minimum (zero) 24 h a day, 7 days a week and the risk of over-chelation.

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High Transferrin Saturation Is Associated with Lower Monocytic Ferritin Heavy Chain Expression in Sickle Cell Anemia Patients

Blood ◽

10.1182/blood.v124.21.4058.4058 ◽

2014 ◽

Vol 124 (21) ◽

pp. 4058-4058

Author(s):

Kleber Yotsumoto Fertrin ◽

Carolina Lanaro ◽

Carla Fernanda Franco-Penteado ◽

Dulcinéia Martins Albuquerque ◽

Betania Lucena Hatzlhofer ◽

...

Keyword(s):

Iron Overload ◽

Sickle Cell ◽

Serum Ferritin ◽

Iron Metabolism ◽

Sickle Cell Anemia ◽

Transferrin Saturation ◽

C Reactive Protein ◽

Iron Storage ◽

Reactive Protein ◽

Ferroxidase Activity

Abstract The pathophysiology of sickle cell anemia (SCA) involves hemolysis, vaso-occlusion and a chronic inflammatory state. Iron overload secondary to blood transfusions is a frequent complication in these patients, but cannot be adequately estimated by serum ferritin levels, because ferritin is also an acute phase reactant. Although excess iron elevates both ferritin levels and transferrin saturation (TSAT) in SCA patients, there is notorious discrepancy between these parameters. Ferritin is composed of heavy (FHC) and light chains (FLC), and ferroxidase activity by FHC is an important cytoprotective mechanism against redox-iron, a product of heme breakdown and largely present in overt iron overload. Previous studies have shown that overexpression of FHC in sickle cell mice prevented free hemoglobin-induced vaso-occlusion. Since ferritin is also highly expressed in circulating monocytes, and these cells have been shown to interact with other cellular types in the sickle cell vaso-occlusive process, we aimed to characterize ferritin chains in monocytes and investigate the relationship with biomarkers of iron metabolism, inflammation and hemolysis. Peripheral blood monocytes from sixteen adult sickle cell anemia patients in steady state were isolated using a double Ficoll-Percoll density gradient to separate monocytes from neutrophils and lymphocytes. FHC, FLC, TLR4 (toll-like receptor 4), and SLC40A1(ferroportin) gene expressions were determined by RT-qPCR. Blood samples were also collected to determine serum ferritin, iron, and TSAT, and plasma levels of lactate dehydrogenase, soluble transferrin receptor, erythropoietin, and C reactive protein. We found that the expression of TLR4, a receptor known to be activated by heme, correlated with FLC, but not FHC expression. Higher TLR4 expression was also associated with higher serum iron, but not with ferritin, TSAT, or LDH. Interestingly, we did not find a correlation between C reactive protein levels and ferritin in this group of patients. As expected, the expressions of both ferritin chains were correlated with each other (P=0.027, r=0.55), but we found the strongest correlation between FHC and TSAT (P=0.0008, r=-0.652). Patients with a TSAT over 40% had significantly lower expression of monocytic FTH (P=0.003). This suggests that either excessive iron can lead to FHC downregulation in monocytes, or that a decrease in monocytic ferritin ferroxidase activity in some SCA patients may impair safe iron storage in ferritin and contribute to the development of higher TSAT, independently from ferritin levels. Our data support that human monocyte regulation of ferritin chains in SCA patients mirrors what has been described in hepatic cells in a sickle cell mouse model. Patients with increased TSAT may be relatively deprived of the cytoprotective ferroxidase activity of FHC, and a relationship between FHC deficiency and complications in SCA remains to be investigated. Further studies should also address whether FHC in monocytes influences cell adhesion, thus supporting an important role for iron trafficking in cells involved in sickle cell vaso-occlusion, and corroborating other studies associating organ damage in SCA with iron metabolism dysregulation. Disclosures No relevant conflicts of interest to declare.

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