211 research outputs found

    Advances in understanding the pathogenesis of red cell membrane disorders

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    Hereditary erythrocyte membrane disorders are caused by mutations in genes encoding various transmembrane or cytoskeletal proteins of red blood cells. The main consequences of these genetic alterations are decreased cell deformability and shortened erythrocyte survival. Red blood cell membrane defects encompass a heterogeneous group of haemolytic anaemias caused by either (i) altered membrane structural organisation (hereditary spherocytosis, hereditary elliptocytosis, hereditary pyropoikilocytosis and Southeast Asian ovalocytosis) or (ii) altered membrane transport function (overhydrated hereditary stomatocytosis, dehydrated hereditary stomatocytosis or xerocytosis, familial pseudohyperkalaemia and cryohydrocytosis). Herein we provide a comprehensive review of the recent literature on the molecular genetics of erythrocyte membrane defects and their reported clinical consequences. We also describe the effect of low-expression genetic variants on the high inter- and intra-familial phenotype variability of erythrocyte structural defects

    Congenital dyserythropoietic anemias

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    Congenital dyserythropoietic anemias (CDAs) are a heterogeneous group of inherited anemias that affect the normal differentiation-proliferation pathways of the erythroid lineage. They belong to the wide group of ineffective erythropoiesis conditions that mainly result in monolinear cytopenia. CDAs are classified into the 3 major types (I, II, III), plus the transcription factor-related CDAs, and the CDA variants, on the basis of the distinctive morphological, clinical, and genetic features. Next-generation sequencing has revolutionized the field of diagnosis of and research into CDAs, with reduced time to diagnosis, and ameliorated differential diagnosis in terms of identification of new causative/modifier genes and polygenic conditions. The main improvements regarding CDAs have been in the study of iron metabolism in CDAII. The erythroblast-derived hormone erythroferrone specifically inhibits hepcidin production, and its role in the mediation of hepatic iron overload has been dissected out. We discuss here the most recent advances in this field regarding the molecular genetics and pathogenic mechanisms of CDAs, through an analysis of the clinical and molecular classifications, and the complications and clinical management of patients. We summarize also the main cellular and animal models developed to date and the possible future therapies

    Inherited microcytic anemias

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    Inherited microcytic anemias can be broadly classified into 3 subgroups: (1) defects in globin chains (hemoglobinopathies or thalassemias), (2) defects in heme synthesis, and (3) defects in iron availability or iron acquisition by the erythroid precursors. These conditions are characterized by a decreased availability of hemoglobin (Hb) components (globins, iron, and heme) that in turn causes a reduced Hb content in red cell precursors with subsequent delayed erythroid differentiation. Iron metabolism alterations remain central to the diagnosis of microcytic anemia, and, in general, the iron status has to be evaluated in cases of microcytosis. Besides the very common microcytic anemia due to acquired iron deficiency, a range of hereditary abnormalities that result in actual or functional iron deficiency are now being recognized. Atransferrinemia, DMT1 deficiency, ferroportin disease, and iron-refractory iron deficiency anemia are hereditary disorders due to iron metabolism abnormalities, some of which are associated with iron overload. Because causes of microcytosis other than iron deficiency should be considered, it is important to evaluate several other red blood cell and iron parameters in patients with a reduced mean corpuscular volume (MCV), including mean corpuscular hemoglobin, red blood cell distribution width, reticulocyte hemoglobin content, serum iron and serum ferritin levels, total iron-binding capacity, transferrin saturation, hemoglobin electrophoresis, and sometimes reticulocyte count. From the epidemiological perspective, hemoglobinopathies/thalassemias are the most common forms of hereditary microcytic anemia, ranging from inconsequential changes in MCV to severe anemia syndromes

    A novel PIEZO1 mutation in a patient with dehydrated hereditary stomatocytosis: A case report and a brief review of literature

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    Background: Dehydrated hereditary stomatocytosis (DHS) or hereditary xerocytosis is a rare, autosomal dominant hemolytic anemia characterized by macrocytosis, presence of stomatocytes and dehydration of red blood cells (RBCs). The dehydration is caused by a defect in cellular cation content. The most frequent expression of the pathology is hemolytic well-compensated anemia with high reticulocyte count, a tendency to macrocytosis, increased mean corpuscular hemoglobin concentration (MCHC) and mild jaundice. We here describe a new mutation of PIEZO1 gene, the most frequent mutated gene in DHS, in a family affected by hereditary hemolytic anemia. Case presentation: We describe the case of a 12-years-old girl with well-compensated chronic hemolysis, increased MCHC and a father who had the same hematological characteristics. After excluding secondary causes of chronic hemolysis and enzymatic defects of the RBCs, microscopic observation of the peripheral blood smear, tests of RBC lysis, ektacytometry, SDS-PAGE and in last instance genetic analysis has been performed. This complex diagnostic workup identified a new variant in the PIEZO1 gene, never described in literature, causative of DHS. This pathogenetic variant was also detected in the father. Conclusions: This case report highlights the importance of a correct and exhaustive diagnostic-workup in patients with clinical suspicious for hemolytic anemia in order to make a differential diagnosis. This is relevant for the management of these patients because splenectomy is contraindicated in DHS due to high thrombotic risk

    Trasferrin receptor 2 gene regulation by microRNA 221 in SH-SY5Y cells treated with MPP+ as Parkinson's disease cellular model

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    Parkinson's disease (PD) is one of the most frequent human neurodegenerations. The neurodegeneration in PD is related to cellular iron increase but the mechanisms involved in iron accumulation remain unclear. Transferrin receptor type 2 (TFR2) is a protein expressed on cell membrane and involved in the cellular iron uptake. We hypothesized that microRNA 221 could regulate the expression of TfR2 in an in vitro model of Parkinson's disease, SH-SY5Y cells treated with MPP+. The miRNA 221 was selected by in silico analysis of several miRNAs predicted to target the TFR2 gene in SHSY5Y cells treated with MPP+. Taqman miRNA assay was used to evaluate the expression of the selected miRNAs. Using a luciferase assay we demonstrated the inhibition of TFR2 by miRNA 221. We show that in PD cellular model, TFR2 expression is regulated by miRNA 221. TFR2 and miR 221 are inversely correlated in SHSY5Y cells during the treatment with MPP+. Moreover, overexpression of miRNA 221 decreases the expression of TFR2, respectively, at the mRNA and protein levels. The inhibition of endogenous miRNA 221 also is able to regulate TFR2. These data suggest that miRNA 221 regulate TFR2 in PD mod

    Antropologia e mistica in Tommaso d’Aquino

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    Nel presente contributo focalizzo, negli scritti di Tommaso d’Aquino, alcuni lineamenti della sua concezione dell’esperienza mistica, compresi alcuni aspetti della sua antropologia filosofica. Comparo la fruizione di Dio e il suo godimento con altri godimenti (anche sessuali). Poi focalizzo quale tipo di conoscenza su Dio è all’uomo possibile e riferisco che l’esperienza mistica è un parziale pregustamento della vita beata paradisiaca: quest’ultima coinvolge anche la volontà e le emozioni, in forma deflagrata. L’esperienza mistica non è una conoscenza diretta di Dio (tranne il caso di Mosè e S. Paolo), però è un parziale anticipo della felicità ultraterrena. Essa comporta una forma di contemplazione e una affettiva cognitio quasi experimentalis di Dio, implica estasi e rapimento.I focus Aquinas’ conception of mystical experience including some aspects of his anthropology. I compare the enjoyment of God with other pleasures (including sexual). I report which knowledge about God is possible and that mystical experience is a foretaste of the Heaven: the latter involves a deflagration of will and emotions. Mystical experience is not a direct knowledge of God (with the exception of Moses and St. Paul), but entails a form of contemplation, an affective ‘cognitio experimentalis’ of God, ecstasy and ‘rapture’
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