Lorena Duca

Erythropoietin in Friedreich ataxia: No effect on frataxin in a randomized controlled trial†‡§

Friedreich ataxia is a rare disease caused by GAA‐trinucleotide‐repeat expansions in the frataxin gene, leading to marked reduction of qualitatively normal frataxin protein. Recently, human recombinant erythropoietin was reported to increase frataxin levels in patients with Friedreich ataxia.

Genetic variability of TMPRSS6 and its association with iron deficiency anaemia.

Transmembrane Protease, Serine 6 (TMPRSS6) has an important role in iron homeostasis and its mutations, performed in TMPRSS6‐deficient mice, have been recently associated with iron‐refractory iron deficiency anaemia (IRIDA). Several variants of TMPRSS6 have been already identified; however the role of polymorphisms and TMPRSS6 haplotypes, causing iron deficiency anaemia, have not yet been investigated. This study sequenced the TMPRSS6 gene in 16 subjects with IRIDA phenotype and identified 27 DNA polymorphisms. Eight single nucleotide polymorphisms and four haplotypes were significantly associated with iron‐refractory anaemia (P < 0·001). Our preliminary results suggest a possible association between specific haplotypes of TMPRSS6 and IRIDA.

Erythrocyte ferritin concentration: Analytical performance of the immunoenzymatic IMx-Ferritin (Abbott) assay

Abstract Together with serum ferritin, erythrocyte ferritincan be a valuable diagnostic tool for evaluating the degree of impaired iron metabolism in different diseases. We collected peripheral blood samples from 64 subjects (22 healthy volunteers, 20 patients with hereditary hemochromatosis, and 22 patients on regular hemodialysis with secondary anemia) to evaluate whether an immunoenzymatic method generally used for serum ferritin can also be used to determine erythrocyte ferritin levels under various conditions of body iron status. Serum and erythrocyte ferritin levels were assayed in parallel using a microparticle enzyme immunoassay (MEIA) IMx-Ferritin kit and an IMx analyzer. The inter-assay imprecision of the serum and erythrocyte ferritin assays was 4.9% and 5.05%, the intra-assay imprecision was 2.2% and 2.3%, and the mean recovery was 102% (range 96–105%) and 101% (range 99–105%), respectively. Both serum and erythrocyte ferritin assays showed a detection limit of 1μg/L and good linearity (R 2=0.99) in the intervals 13.9–443 and 3.9–135.6μg/L, respectively. Our findings demonstrate that the IMx-Ferritin assay currently used to measure serum ferritin levels can also be adopted to measure erythrocyte ferritin insofar as it clearly discriminates high and low erythrocyte ferritin levels in cases of both iron overload and deficiency.

Growth differentiation factor 15 expression and regulation during erythroid differentiation in non-transfusion dependent thalassemia

In the last two decades the research interest in biochemical risk markers has exploded. Among the new biomarkers examined, GDF15, a cytokine member of the transforming growth factor-β (TGFβ) superfamily, is emerging as a biomarker of potential utility in a variety of diseases (cardiovascular disease, diabetes, chronic kidney disease, acute respiratory distress syndromes, rheumatoid arthritis, and many types of cancer) [1,2]. Under normal conditions, GDF15 is expressed at low levels in all organs (serum levels: 200–1150 pg/mL). Although the exact biological functions of GDF15 are still poorly understood, it has been shown to be involved in regulating inflammatory and apoptotic pathways and its expression is upregulated in many different pathological conditions, including inflammation, cancer, cardiovascular disease, pulmonary disease and renal disease [3]. Furthermore, GDF15 concentrations are strongly elevated in disorders hallmarked by increased ineffective erythropoiesis, such as β thalassemia syndromes (up to 100,000 pg/mL), congenital dyserythropoietic anemias (10,000 pg/mL) and myelodysplastic syndromes (5000 pg/mL) [4]. Here, we focused on thalassemia and ineffective erythropoiesis as possible regulator for GDF15 levels. Non-transfusion dependent thalassemia (NTDT) syndromes are characterized by ineffective erythropoiesis and iron overload; GDF15 has been proposed as a link between these two conditions. There is evidence that ineffective erythropoiesis inhibits expression of hepcidin, a hepatic peptide hormone that regulates iron release into the blood stream from duodenal enterocytes, hepatocytes and macrophages [5]. The molecular mechanisms involved in hepcidin suppression in response to increased erythropoietic activity remain unclear, although it was hypothesized that some soluble proteins secreted fromdeveloping erythroblastsmay play a role; GDF15was suggested as one of such proteins. The mechanisms by which GDF15 synthesis is regulated during erythroid differentiation are not known; it has been proposed that GDF15 itself might be responsive to intracellular iron levels [6]. Moreover, correlation between GDF15 levels and the degree of ineffective erythropoiesis has been never explored. In the current study, we evaluated GDF15 expression and regulation during normal and thalassemic erythroid differentiation in vitro andwe investigated the relationship between GDF15 levels and the degree of ineffective erythropoiesis. CD34 cells obtained, after informed consent, from peripheral blood of healthy volunteers (control group) and NTDT patients were cultured for 14 days with a medium stimulating erythroid differentiation [7]. GDF15 expression was evaluated at mRNA levels by real-time PCR (2^-dCt) at different time points (day 0: erythroid progenitors, day 7: proerythroblasts, and day 14: mature erythroblasts) and at protein levels by Western-blot analysis at day 14 of culture. GDF15 secretion

Circulating cell-free DNA and ineffective erythropoiesis in nontransfusion-dependent β-thalassemia: Correspondence

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Non-transferrin-bound iron and oxidative stress during allogeneic hemopoietic stem cell transplantation in patients with or without iron overload

Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts Viral Pathogenesis Section, Laboratory of Immunoregulation (LIR), National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, Maryland Section of Microbiology and Medical Genetics, Department of Medical Sciences, University of Ferrara, Ferrara, Italy Correspondence Prof. Dario Di Luca, Department of Medical Sciences, University of Ferrara, Via Borsari 46, 44121 Ferrara, Italy. Email: dario.diluca@unife.it