Enzyme replacement therapy improves erythropoiesis and iron dysregulation in Gaucher disease.

Anemia and hyperferritinemia are frequent findings at diagnosis of Gaucher disease (GD). Macrophage-independent dyserythropoiesis and abnormal iron metabolism have been shown. We evaluated hematological and iron status at diagnosis (T0) and the effect of enzyme replacement therapy (ERT) on erythropoiesis and iron utilization over 5-year follow-up in type 1 GD patients and in an ex vivo model of erythropoiesis from CD34 + peripheral blood cells. At T0, 41% of patients had anemia and 51% hyperferritinemia. Hemoglobin increased from 12.6 (T0) to 13.9 g/dL (T6), GFD15, a marker of ineffective erythropoiesis, decreased from 5401 to 710 pg/ml, and serum ferritin decreased from 614 to 140 mcg/L (p < 0.001). In parallel, transferrin saturation (TSAT) increased. Hepcidin, although in the normal range, decreased from T0 to T6. Ex vivo studies showed that ERT restores the erythroid cells derived from CD34 + impaired ability to differentiate. During ERT, an increase in TFRC expression, consistent with the ability of erythroid precursors to uptake iron, and a reduction in HAMP and concomitant increase in SLC40A1 were observed. This is the largest study with a longitudinal follow-up evaluating erythropoiesis and iron metabolism, combining clinical and ex vivo data in GD. Iron dysregulation likely contributes to anemia, and ERT, by improving iron distribution, improves erythropoiesis.

Epidemiological shift of glucose-6-phosphate dehydrogenase mutations in northern Italy in the last 15 years.

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is an X-linked recessive hemolytic anemia caused by mutations in G6PD gene. The distribution and frequency of genetic variants differ depending on ethnicity and geographical areas. Because of new migrations different variants are now present in Europe. This retrospective study aims to identify variants among the G6PD deficient subjects referred since 2004 to IRCCS Ca' Granda Foundation Hospital in Milan. The subjects were divided into 3 groups: group 1 (2004-2008), group 2 (2009-2013), and group 3 (2014-2018). During 15 years a significant decrease of the Mediterranean and an important increase of the African, Asian, and uncommon variants (classified as Others) have been observed. Three new mutations were found: in group 2 heterozygosity for c.[1454G > A] (Gly485Asp) in an adult female with severe anemia, high bilirubin levels and G6PD activity of 0,69 (IU/gHb) and heterozygosity for c.[584A > G] (Gln195Arg) in an elderly woman of Italian origin showing only anemia and enzymatic activity of 1,54 (IU/gHb) were detected. In group 3 hemizygosity for c.[670A > T] (Ile224Phe) in an adult Chinese man without anemia but with total absence of G6PD activity was found. These data reflect the appearance of uncommon G6PD mutations in northern Italy, probably due to new migrations, as consequence G6PD characterization becomes a diagnostic issue.

The role of TMPRSS6 polymorphisms in iron deficiency anemia partially responsive to oral iron treatment.

Iron refractory iron deficiency anemia (IRIDA) is a rare hereditary disease caused by mutations in TMPRSS6 gene encoding Matriptase-2, a negative regulator of hepcidin transcription. Up to now, 53 IRIDA patients from 35 families with different ethnic origins have been reported and 41 TMPRSS6 mutations have been identified. TMPRSS6 polymorphisms are more frequent than mutations, and have been associated with variation in iron and hematologic parameters. Our study evaluated their presence in 113 subjects with iron deficiency anemia (IDA) partially responsive to oral iron therapy and in 50 healthy blood donors. Thalassemic trait was diagnosed in 38 patients. Sequencing analysis of TMPRSS6 gene revealed that the frequency of several polymorphisms was markedly different between IDA subjects and controls. In particular, the V736A TMPRSS6 polymorphism was associated to moderately lower hemoglobin, mean corpuscular volume, and mean corpuscular hemoglobin levels, and in thalassemia carriers with marked anemia and microcytosis. A new variant-H448R- and two uncommon polymorphisms -A719T and V795I- were also identified. These results indicate that TMPRSS6 polymorphisms are more frequent in subjects with persistent IDA than in healthy controls, and in thalassemia carriers V736A variant may account for lower hemoglobin and MCV levels. Further studies in larger court of patients are necessary to identify potential haplotypes and polymorphisms responsible for low response to oral iron treatment and may be useful for planning a correct iron supplementation.

Complete Chloroplast Genome of an Endophytic Ostreobium sp. (Ostreobiaceae) from the U.S. Virgin Islands.

We present the complete chloroplast genome sequence of an endophytic Ostreobium sp. isolated from a 19th-century coralline red algal specimen from St. Croix, U.S. Virgin Islands. The chloroplast genome is 84,848 bp in length, contains 114 genes, and has a high level of gene synteny to other Ostreobiaceae.

Associated Effect of SLC40A1 and TMPRSS6 Polymorphisms on Iron Overload.

Mutations in the ferroportin (FPN) gene SLC40A1 alter iron recycling and cause disturbances in iron homeostasis. The variants of TMPRSS6 contribute to the development of iron deficiencies. In this study, we determined the role of FPN and TMPRSS6 gene polymorphisms in the modulation of iron homeostasis based on biochemical parameters. PCR analysis and sequencing were performed to determine the single nucleotide polymorphisms (SNPs) SLC40A1 c.44−24G>C (rs1439816), SLC40A1 c.663T>C (rs2304704), and TMPRSS6 c.2207T>C (rs855791). Hemoglobin concentration and iron status were determined by standard procedures. We studied 79 iron-loaded individuals for SLC40A1 polymorphisms. Interestingly, 35/79 individuals with SLC40A1 SNPs also carried a TMPRSS6 c.2207T>C polymorphism. The biochemical values of the iron overloaded individuals were compared to those of the individuals carrying TMPRSS6 SNPs and the healthy individuals (wild-type group). The ferritin concentration, transferrin saturation % (TS%), and hemoglobin concentration were significantly higher in the participants with FPN SNPs than in the other three groups. The ferritin concentration and TS% were higher in participants with both SLC40A1 and TMPRSS6 SNPs than in the TMPRSS6 and wild-type groups, while hemoglobin concentration was significantly higher than that in the TMPRSS6 SNP group only. The participants with TMPRSS6 SNPs had significantly lower ferritin concentration, TS%, and hemoglobin concentration than all the other groups. SLC40A1 and TMPRSS6 SNPs might act in the opposite direction, preventing the development of severe iron overload, and the modulation of the iron status by TMPRSS6 SNPs might provide protection.

COVID-19, inflammatory response, iron homeostasis and toxicity: a prospective cohort study in the Emergency Department of Piacenza (Italy).

BACKGROUND AND AIM: Dysregulation of iron metabolism and hyper-inflammation are two key points in the pathogenesis of coronavirus disease 2019 (COVID-19). Since high hepcidin levels and low serum iron can predict COVID-19 severity and mortality, we decided to investigate iron metabolism and inflammatory response in 32 COVID-19 adult patients with a diagnosis of COVID-19 defined by a positive result of RT-PCR nasopharyngeal swab, and admitted to an Italian emergency department for acute respiratory failure at different degree. METHODS: Patients were stratified in 3 groups based on PaO2/FiO2 ratio at admission: 13 (41%) were normoxemic at rest and suffered from exertional dyspnea (group 1); 14 (44%) had a mild respiratory failure (group 2), and 5 (15%) a severe hypoxiemia (group 3). RESULTS: White blood cells were significantly higher in group 3, while lymphocytes and hemoglobin were significantly reduced. Serum iron, transferrin saturation, non-transferrin-bound iron (NTBI) and ferritin were significantly increased in group 2. All the groups showed high hepcidin levels, but in group 3 this parameter was significantly altered. It is noteworthy that in group 1 inflammatory and oxidative indices were both within the normal range. CONCLUSIONS: We are aware that our study has some limitations, the small number of enrolled patients and the short period of data collection, but few works have been performed in the Emergency Room. However, we strongly believe that our results confirm the pivotal role of both iron metabolism dysregulation and hyper-inflammatory response in the pathogenesis of tissue and organ damage in COVID-19 patients.

Microcytosis in Erythropoietic Protoporphyria.

Partial deficiency of the last enzyme of the heme biosynthetic pathway, namely, ferrochelatase (FECH), is responsible for erythropoietic protoporphyria (EPP) in humans. This disorder is characterized by painful skin photosensitivity, due to excessive protoporphyrin IX (PPIX) production in erythrocytes. Although several papers report the presence of iron deficiency anemia in about 50% of EPP patients, there is still no a conclusive explanation of the why this occurs. In the present work, we explored hematological indices and iron status in 20 unrelated Italian EPP patients in order to propose a new hypothesis. Our data show that microcytosis is present in EPP patients also in the absence of anemia and iron deficiency with a link between PPIX accumulation and reduced MCV, probably indicating an indirect condition of heme deficiency. Patients studied had a downward shift of iron parameters due to increased hepcidin concentrations only in a state of repleted iron stores. Interestingly, hemoglobin synthesis was not limited by iron supply except in cases with further iron loss, in which concomitantly increased soluble transferrin (Tf) receptor (sTfR) levels were detected. The mechanisms involved in the iron uptake downregulation in EPP remain unclear, and the role of PPIX accumulation in microcytosis.

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.

Activin Receptor-Ligand Trap for the Treatment of ß-thalassemia: A Serendipitous Discovery.

ß-thalassemia is a hereditary disorder caused by defective production of ß-globin chains of hemoglobin (Hb) that leads to an increased α/ß globins ratio with subsequent free α-globins. Alpha globin excess causes oxidative stress, red blood cells membrane damage, premature death of late-stage erythroid precursors, resulting in ineffective erythropoiesis. The transforming growth factor ß (TGF-ß) superfamily signaling acts on biological processes, such as cell quiescence, apoptosis, proliferation, differentiation, and migration, and plays an essential role in regulating the hematopoiesis. This pathway can lose its physiologic regulation in pathologic conditions, leading to anemia and ineffective erythropoiesis. Activin receptor-ligand trap molecules such as Sotatercept and Luspatercept downregulate the TGF-ß pathway, thus inhibiting the Smad2/3 cascade and alleviating anemia in patients with ß-thalassemia and myelodysplastic syndromes. In this review, we describe in extenso the TGF-ß pathway, as well as the molecular and biological basis of activin receptors ligand traps, focusing on their role in various ß-thalassemia experimental models. The most recent results from clinical trials on sotatercept and luspatercept will also be reviewed.

Mutation analysis of hepcidin and ferroportin genes in Italian prospective blood donors with iron overload.

Maintenance of iron balance is essential for humans and requires the coordinate regulation of iron transport into plasma from dietary sources in the duodenum, from recycled senescent red cells in macrophages, and from storage in hepatocytes. Hepcidin, a recently identified antimicrobial peptide produced in the liver, has been shown to play a central role in the homeostatic regulation of iron absorption and distribution [1]. It is a negative regulator of iron absorption in the small intestine and of iron release from macrophages engaged in the recycling of iron senescent erythrocytes [2]. The human hepcidin gene contains three exons that encode a 72-aa precursor (pro-hepcidin) with a characteristic furin cleavage site immediately N-terminal to the 25-aa major hepcidin species found in plasma and urine [3]. Recently, hepcidin has been shown to regulate iron homeostasis by interaction with ferroportin, an iron cellular exporter highly expressed in absorptive enterocytes, macrophages, hepatocytes, and placental cells [4].

Changes in erythropoiesis, iron metabolism and oxidative stress after half-marathon.

OBJECTIVE: In marathon runners changes in red blood cell count, haematocrit and haemoglobin in relation to haemodilution have been reported. Moreover, it has been hypothesized that strenuous exercise induces oxidant stress through several different mechanisms. This study investigated the haematological variables, iron status and oxidative indices before, immediately and 48 h after a race in 8 healthy trained males aged 33-44 years running a 21-km marathon in 79 +/- 3 min. METHODS: The haematological parameters were determined by standard procedures. Erythropoietin and soluble-transferrin receptor were evaluated immunoenzymatically. Nontransferrin-bound iron (NTBI) was assayed by high-performance liquid chromatography after nitrilotriacetic acid chelation. Malonyldialdehyde (MDA) concentration was assayed colorimetrically. RESULTS: The total number of reticulocytes rose significantly after the run with a significant increase in the high-RNA-content fraction (14 +/- 5, p < 0.0006). Erythropoietin rose by 26% (15.0 +/- 2.8 mU/ml, p < 0.004) and by 25% (14.9 +/- 2.13 mU/ml, p < 0.02) immediately and 48 h after the race, respectively. Serum iron and serum ferritin remained unchanged but NTBI and serum MDA increased significantly immediately after running (1.16 +/- 0.40 mmol/l, p < 0.0008; 0.76 +/- 0.16 mmol/l, p < 0.0001). Significant positive correlations at any time between MDA and polymorphonuclear neutrophils (p = 0.0005), MDA and NTBI (p = 0.0018), polymorphonuclear neutrophils and NTBI (p = 0.0008) and between lactate dehydrogenase and NTBI (p = 0.0212) were observed. CONCLUSIONS: The erythropoietic changes observed in marathon runners are the results of several interacting mechanisms that involve either the haemopoietic system per se or erythrocyte haemolysis and oxidative stress.