Elisa Ferro

Oxidative damage and genotoxicity biomarkers in transfused and untransfused thalassemic subjects.

Chronic anemia and tissue hypoxia increase intestinal iron absorption and mitochondrial impairment in thalassemic patients. Regular blood transfusions improve hemoglobin levels but determine an iron overload that induces reactive oxygen species (ROS) overproduction. The aim of this study was to assess cellular oxidative damage by detection of ROS, lipid peroxidation, 8-oxo-dG, and mitochondrial transmembrane potential (Δψ(m)) in transfused and untransfused thalassemic patients. We have also evaluated genotoxicity by CBMN and comet assay. Our data show that ROS and lipid hydroperoxides are significantly higher in thalassemic patients than in controls, especially in untransfused thalassemia intermedia patients. Moreover, the latter have a significant decrease in Δψ(m) that highlights the energetic failure in hypoxic state and the ROS overproduction in the respiratory chain. 8-OHdG levels are higher in thalassemics than in controls, but do not differ significantly between the two patient groups. Both genotoxicity biomarkers highlight the mutagenic potential of hydroxyl radicals released by iron in the Fenton reaction. Values for percentage of DNA in the comet tail and micronuclei frequency, significantly higher in transfused patients, could also be due to active hepatitis C virus infection and to the many drug treatments. Our biomonitoring study confirms the oxidative damage in patients with thalassemia major and shows an unexpected cellular oxidative damage in untransfused thalassemic patients. In addition to iron overload, the results highlight the important role played by hypoxia-driven mitochondrial ROS overproduction in determining oxidative damage in β-thalassemias.

A child with severe iron-deficiency anemia and a complex TMPRSS6 genotype

ABSTRACT Objectives: We report a case of a 7-year-old girl with severe hypochromic microcytic anemia, who was unresponsive to classical iron supplements. We suspected IRIDA, iron-refractory iron-deficiency anemia, a genetic iron metabolism disorder, caused by TMPRSS6 variations. TMPRSS6 encodes matriptase-2, a negative regulator of hepcidin, and its pathological variants are related to normal to high levels of hepcidin. We analyzed the TMPRSS6 gene and we improved clinical management of the patient, selecting the appropriate supplementation therapy. Intervention & Technique: The parenteral iron therapy was started, but the patient was only partially responsive and the anemia persisted. To confirm the diagnosis, the TMPRSS6 gene sequence was analyzed by DNA sequencing and other relevant biochemical parameters were evaluated. Results: The TMPRSS6 sequence analysis showed a complex genotype with a rare heterozygous missense variant, in addition to other common polymorphisms. The serum hepcidin value was normal. We unexpectedly observed a normalization of patient’s hemoglobin (Hb) levels only after liposomal iron treatment. Discussion and Conclusion: The proband was symptomatic for IRIDA during a critical phase of growth and development, but we did not find a clearly causative genotype. A long-term result, improving stably patient’s Hb levels, was obtained only after liposomal iron supplementation. Children may be at greater risk for iron deficiency and the degree of anemia as well as the response to the iron supplements varies markedly patient to patient. Here, we show the importance of comprehensive study of these patients in order to collect useful information about genotype–phenotype association of genes involved in iron metabolism.

HIF1α and Glut1 receptor in transfused and untransfused thalassemic patients

Keywords: hypoxia inducible factor 1; glucose transporter 1; hypoxia; transfusion; erythropoiesis

Genotoxic effect of iron overload and disease complications in transfused β thalassaemic patients

In previously reported studies, we observed significantly high genotoxicity biomarkers in regularly transfused thalassaemic patients, thus, in this study, we better investigated the genotoxic effect of iron overload and of thalassaemia complications, including their drug treatments. The assessment was performed in 64 regularly transfused thalassaemic patients using cytokinesis-block micronucleus and comet assays. All patients were splenectomised and undergoing iron chelation therapy. To reduce hypoxia-induced oxidative damage, the patients with haemoglobin levels <9.5 g/dL were excluded. Serum concentrations of ferritin, iron, transferrin and the percentage of transferrin saturation, as well as cardiac and hepatic T2* magnetic resonance imaging, were considered to evaluate serum and organ siderosis.All genotoxic biomarkers significantly differed between patients and healthy subjects. Iron intake via blood transfusions was inversely related to percentage of DNA in tail. The disease complications affecting endpoints were active Hepatitis C virus infection, drug therapy for osteoporosis (i.e. bisphosphonates) and hormone replacement therapy for hypogonadism.The results, highlighting the combined effect of iron overload and, mainly, disease complications, including their respective pharmacological treatments, confirmed the increased cancer risk in thalassaemic patients.

The role of anaemia in oxidative and genotoxic damage in transfused β-thalassaemic patients

ABSTRACT Objectives: Redox imbalance and genotoxic damage are commonly observed in β thalassaemic patients. The aim of this study was to assess the role of anaemia in oxidative and genotoxic damage in regularly transfused thalassaemic patients, undergoing iron chelation therapy. Methods: We studied the relationships of haematological, biochemical and clinical parameters with oxidative (reactive oxygen species and 8-oxo-7,8-dihydro-2′-deoxyguanosine) and genotoxic biomarkers (Comet assay and cytokinesis-block micronucleus test) in blood samples from 105 patients. To reduce the early effect of redox-active iron, samples were collected when pharmacokinetics of the iron chelators ensured their maximum effectiveness. The transfusion regimen, cardiac and hepatic magnetic resonance imaging T2* were evaluated to characterize the patient cohort. Labile plasma iron (LPI) was also assayed. Results: Haemoglobin level had a significant effect on ROS, %DNA in the tail and micronuclei-micronucleated cell frequency (p < 0.05). Higher Hb values reduced redox imbalance. LPI, detectable in 50.5% of patients, was related to the number of apoptotic and necrotic lymphocytes (p = 0.03), demonstrating the cytotoxic effect of iron. Discussion: The results highlight that an adequate transfusion regimen is essential to limit oxidative and genotoxic damage in β-thalassemic patients undergoing chelation therapy. Conclusion: Owing to the higher risk of cancer in the thalassaemic cohorts, specific genotoxicity/oxidative biomarkers should be monitored in order to ameliorate and formulate more personalized disease management.

Soluble hemojuvelin in transfused and untransfused thalassaemic subjects

The hemojuvelin‐bone morphogenetic protein axis is the principal iron‐dependent mechanism of hepcidin regulation. The determination of soluble hemojuvelin (sHJV) levels could allow for a better understanding of the pathophysiological mechanisms of hepcidin regulation in thalassaemia.

FTL c.-168G>C Mutation in Hereditary Hyperferritinemia Cataract Syndrome: A New Italian Family

We describe a new Italian family with 7 members affected by hereditary hyperferritinemia cataract syndrome (HHCS), an uncommon autosomal dominant disease caused by mutations of the iron-responsive element (IRE) of the ferritin light chain (FTL) gene determining its overexpression. The family diagnosis of HHCS took place after finding high ferritin levels in a 6-year-old girl. Seven members of the family had bilateral and symmetrical cataracts, normal iron, and hematological parameters except for high serum ferritin levels. About 160 families/unrelated cases with HHCS are known worldwide. This report documents a second Italian family, with a c.-168G>C mutation that is located in the highly conserved 3-nucleotide bulge structure of the FTL in the 5′ untranslated region. This case shows how important the family history is in reaching a correct diagnosis and avoiding unnecessary and invasive analysis. HHCS should be considered in the differential diagnosis of childhood hyperferritinemia, especially in the presence of normal transferrin saturation.

Co-inheritance of HBB:c.−106G > C, a rare single nucleotide variation at position −56 relative to transcription initiation site, with other known mutations in the globin clusters

ABSTRACT Objectives: We performed molecular analysis to evaluate clinical implications of a rare nucleotide change, particularly when co-inherited with other known mutations in the globin clusters, in order to conduct an appropriate genetic counselling. Methods: Complete blood cell counts and high-performance liquid chromatography were the routine first level analysis for patients referred to our Hospital Center in Palermo to undergo the screening test for haemoglobinopathies. Sequencing analysis was the selected method for the phenotypic characterization, especially in case of new or very rare mutations in globin genes. Results: We report data of a rare single nucleotide variation at position −56 relative to transcription initiation site (NM_000518.4(HBB):c.−106G > C), identified in ten patients of Italian origin during the screening programme of the ‘Sicilian population’. It was found in simple heterozygosity (n = 8), in association with beta haemoglobin variant Hb S (n = 1) and in heterozygosity with beta-thalassaemic allele IVS-I-1 G->A [(HBB):c.92 + 1G > A] and ααα anti3.7 rearrangement (n = 1). Discussion: Heterozygous subjects for this substitution showed normal haematological and electrophoretic features. Heterozygotes for this mutation and other defect in globin genes showed the classical phenotype of a healthy carrier, therefore it can be considered a benign variant that does not alter the production and function of haemoglobin. Conclusion: This is another example of rare or new nucleotide variations whose identification and characterization is crucial in order to carry out appropriate genetic counselling to a potential risk couple.