Transferrin Insufficiency and Iron Overload in Follicular Fluid Contribute to Oocyte Dysmaturity in Infertile Women With Advanced Endometriosis.

Purpose: To screen out specific protein with different concentration in follicular fluid from advanced endometriosis and determine its direct effect on mouse oocytes matured in vitro. Methods: FF samples were obtained from 25 patients (EMS group, n = 15; control group, n = 10) to screen the differential proteins by using iTRAQ Labeling and 2D LC-MS. Transferrin (TRF) in was found significantly decreased in EMS group, which was verified using ELISA in enlarged FF samples (EMS group, n = 31; control group, n = 27). The contents of ferric ion in FFs were detected by ELISA and TRF saturations were calculated in two groups. Germinal vesicle (GV) oocytes of mouse were maturated in vitro interfered with the FFs in five groups, whose concentrations of TRF were modulated, and maturation in vitro rates were compared among groups. Results: The reduced concentration of TRF with three analogs and increased concentration of ferric ion were found in the FF of the EMS group (p < 0.05). The numerical values of TSAT was 54.8% in EMS group, indicating iron overload in the FF. The EMS-FF showed significantly decreased maturation in vitro rate (p < 0.05) of mouse oocytes, which was improved with the supplementation of TRF, compared with the control-FF. The effect was blocked by the TRF antibody (p < 0.05). Conclusions: Being aware of the relatively small sample size, our results possibly suggest that TRF insufficiency and iron overload in FF from advanced EMS contribute to oocytes dysmaturity, which may be a cause of EMS-related infertility.

Nitroprusside induces melanoma ferroptosis with serum supplementation and prolongs survival under serum depletion or hypoxia.

BACKGROUND: When proliferating tumor cells expand to areas distant from vascular sites, poor diffusion of oxygen and nutrients occur, generating a restrictive hypoxic gradient in which susceptible tumor cells die. The heterogeneous population surviving hypoxia and metabolic starvation include de-differentiated cancer stem cells (CSC), capable of self-renewing tumor-initiating cells (TICs), or those that divide asymmetrically to produce non-tumor-initiating differentiated (NTI-D) cell progeny. Under such restrictive conditions, both populations slowly proliferate, entering quiescence or senescence, when exiting from cell cycle progression. This may drive chemoresistance and tumor recurrence, since most anti-cancer treatments target rapidly proliferating cells. PURPOSE: Since persistent or additional stress may increase NTI-D cells conversion to TICs, we investigated whether nutrient depletion or hypoxia influence expression of tyrosinase, a crucial enzyme for melanin synthesis, and B16 melanoma survival, when exposed to iron-dependent cell death oxidative stress produced by the Fenton reaction, resembling ferroptosis. RESULTS: -a) proliferating B16 melanoma with 10% serum-supplementation (10%S) normoxically express hypoxia inducible factor 1α (HIF1α) but lose tyrosinase, in contrast to those transiently exposed to (SF) serum-free medium, in which both HIF1α and tyrosinase are co-expressed; b) in contrast to the resistance to SNP toxicity in (SF) cells with higher tyrosinase expression, those in (10%S) are killed by iron from nitroprusside/ferricyanide (SNP) irrespective of exogenous H2O2, in a reaction antagonized by the anti-oxidant and MEK inhibitor UO126; c) Moreover, under transient serum depletion, SNP cooperates with hypoxia (1.5% oxygen), prolonging B16 melanoma (SF) survival; d) the hypoxia mimetic CoCl2 inhibits proliferation-associated cyclin A, irrespective of SNP, in (10%S) cells or in transiently serum-depleted (SF) cells. However, only in the latter cells, CoCl2 but not SNP, induce loss of HIF1α and apoptosis-associated PARP cleavage; e) longer term adaptation to survive serum depletion, generates (SS) cells resistant to SNP toxicity, which aerobically co-express HIF1α and tyrosinase. In SS B16 melanoma, exogenous non-toxic 100 µM H2O2 super-induces the ratio of tyrosinase to HIF1α. However, co-treatment of SS-B16 cells with SNP plus exogenous H2O2, partly increases PARP cleavage by reciprocally decreasing tyrosinase expression. SIGNIFICANCE: - These results suggest that a phenotypic plasticity in response to depletion of nutrients and/or oxygen, helps decide whether melanoma cells undergo either death by ferroptosis, or resistance to it, when challenged by the same exogenous oxidative stress (iron ± H2O2).

A new case of congenital atransferrinemia with a novel splice site mutation: c.293-63del.

Congenital atransferrinemia is an extremely rare autosomal recessive disorder resulting in the complete absence or extremely reduced amount of transferrin. In this study, we describe the first case of congenital atransferrinemia in Tunisia and the 18th patient in the reported data. The patient was referred to our hospital to explore a severe hypochromic and microcytic anemia. The laboratory evaluation including hematological and biochemical examination was performed in the proband and her parents. All exons of the transferrin gene were PCR amplified. The products were screened for mutations by direct sequencing. Based on laboratory and clinical findings, diagnosis of congenital atransferrinemia was confirmed. DNA sequencing revealed the presence of a novel homozygous deletion (c.293-63del) in the intron 13. This mutation is predicted to generate a higher score cryptic branch point leading to the production of an altered mRNA molecule. The second previously reported missense mutation p.Arg609Trp. Crystallographic structure analyzes demonstrate that the mutation would probably lead to significant conformational change not allowing the expression of transferrin protein. Current molecular characterization of this novel transferrin abnormality puts to the proof the variability in onset, first blood transfusion, and phenotypic expression in atransferrinemic patients.

Variables associated with subclinical atherosclerosis among rheumatoid arthritis patients of Gulf Cooperative Council countries.

OBJECTIVES: To evaluate the cardiovascular disease (CVD) as demonstrated by carotid intima-media thickness (cIMT) and the cluster risk factors of CVD including traditional and non-traditional, urinary functions, iron buildup, and hemorheology in rheumatoid arthritis (RA) patients of Gulf Cooperative Council (GCC) countries. METHODS: Carotid intima-media thickness was obtained from 216 RA patients, free of atherosclerotic diseases. The correlation between cIMT and the possible CVD risk factors was carried out using regression analysis. Results: The mean cIMT was observed as 0.58±0.11 mm. Mean age was 48±13 years. Univariate analysis revealed a positive association (p less than 0.05) between cIMT and age, body mass index, systolic blood pressure (SBp), and diastolic blood pressure, c-reactive protein (CRP), triglycerides (TG), low-density lipoprotein (LDL), erythrocyte sedimentation rate (ESR), hemoglobin (Hb), hematocrit (Hct), mean cell volume, platelet, monocytes, eosinophils, ferritin, creatinine, and uric acid. Negative relationship was observed between cIMT and glomerular filtration rate (GFR), transferrin, and high-density lipoprotein. Multiple linear regression analysis exhibited a positive association between cIMT and the age, LDL, eosinophil, SBp, and the ESR, whereas, negative connection with the GFR and transferrin. Conclusion: In this study, we found that the eosinophils, and low transferrin, are the potential candidates for the CVD risk factors in RA patients. Fasting blood glucose level was also observed to be a significant risk factor in diabetic as well as non-diabetic RA. The remaining CVD risk factors in RA patients of GCC countries including older age, high SBp, ESR, LDL, and low GFR were similar to the international population.

Addition of oral iron to plasma transfusion in human congenital hypotransferrinemia: A 10-year observational follow-up with the effects on hematological parameters and growth.

Congenital hypotransferrinemia (OMIM 209300) is an extremely rare disorder of inherited iron metabolism. Since its description in 1961, only 16 cases have been reported. The defective gene and molecular defect causing this disorder and clinicolaboratory findings seen in the homozygous and heterozygous states have been documented in both humans and mice. However, due to the lack of follow-up studies of the described cases, the long-term prognosis remains unknown. We present a 10-year observational follow-up of a patient previously diagnosed on a molecular basis who was treated with a unique therapy of plasma transfusion fortified with oral iron, with satisfactory clinicolaboratory responses.

Dysregulated iron metabolism in the choroid plexus in fragile X-associated tremor/ataxia syndrome.

Fragile X-associated tremor/ataxia syndrome (FXTAS) is a late-onset neurodegenerative disorder associated with premutation alleles of the FMR1 gene that is characterized by progressive action tremor, gait ataxia, and cognitive decline. Recent studies of mitochondrial dysfunction in FXTAS have suggested that iron dysregulation may be one component of disease pathogenesis. We tested the hypothesis that iron dysregulation is part of the pathogenic process in FXTAS. We analyzed postmortem choroid plexus from FXTAS and control subjects, and found that in FXTAS iron accumulated in the stroma, transferrin levels were decreased in the epithelial cells, and transferrin receptor 1 distribution was shifted from the basolateral membrane (control) to a predominantly intracellular location (FXTAS). In addition, ferroportin and ceruloplasmin were markedly decreased within the epithelial cells. These alterations have implications not only for understanding the pathophysiology of FXTAS, but also for the development of new clinical treatments that may incorporate selective iron chelation.

Hereditary hypotransferrinemia can lead to elevated transferrin saturation and, when associated to HFE or HAMP mutations, to iron overload.

As our understanding of iron metabolism improves through the more accurate description of iron metabolism actors, new causes of iron overload are identified. We, here, report 16 cases of hereditary hypotransferrinemia related to 4 previously undescribed TF (transferrin) mutations (p.Val221Gly, p.Arg609Trp, p.Glu370Lys, p.Tyr533X and p.Cys421Arg). We show that, besides increasing serum transferrin saturation without iron overload, hypotransferrinemia, when associated to mutations in HFE or HAMP or to acquired factors, can lead to clinically relevant iron burden. These cases emphasize the usefulness of serum transferrin determination in the diagnostic evaluation of iron overload and the importance for clinicians to be aware of this syndrome.

Hepatocyte divalent metal-ion transporter-1 is dispensable for hepatic iron accumulation and non-transferrin-bound iron uptake in mice.

UNLABELLED: Divalent metal-ion transporter-1 (DMT1) is required for iron uptake by the intestine and developing erythroid cells. DMT1 is also present in the liver, where it has been implicated in the uptake of transferrin-bound iron (TBI) and non-transferrin-bound iron (NTBI), which appears in the plasma during iron overload. To test the hypothesis that DMT1 is required for hepatic iron uptake, we examined mice with the Dmt1 gene selectively inactivated in hepatocytes (Dmt1(liv/liv) ). We found that Dmt1(liv/liv) mice and controls (Dmt1(flox/flox) ) did not differ in terms of hepatic iron concentrations or other parameters of iron status. To determine whether hepatocyte DMT1 is required for hepatic iron accumulation, we crossed Dmt1(liv/liv) mice with Hfe(-) (/) (-) and hypotransferrinemic (Trf(hpx/hpx) ) mice that develop hepatic iron overload. Double-mutant Hfe(-) (/) (-) Dmt1(liv/liv) and Trf(hpx/hpx) ;Dmt1(liv/liv) mice were found to accumulate similar amounts of hepatic iron as did their respective controls. To directly assess the role of DMT1 in NTBI and TBI uptake, we injected (59) Fe-labeled ferric citrate (for NTBI) or (59) Fe-transferrin into plasma of Dmt1(liv/liv) and Dmt1(flox/flox) mice and measured uptake of (59) Fe by the liver. Dmt1(liv/liv) mice displayed no impairment of hepatic NTBI uptake, but TBI uptake was 40% lower. Hepatic levels of transferrin receptors 1 and 2 and ZRT/IRT-like protein 14, which may also participate in iron uptake, were unaffected in Dmt1(liv/liv) mice. Additionally, liver iron levels were unaffected in Dmt1(liv/liv) mice fed an iron-deficient diet. CONCLUSION: Hepatocyte DMT1 is dispensable for hepatic iron accumulation and NTBI uptake. Although hepatocyte DMT1 is partially required for hepatic TBI uptake, hepatic iron levels were unaffected in Dmt1(liv/liv) mice, suggesting that this pathway is a minor contributor to the iron economy of the liver.

Iron deficiency after arrival is associated with general cognitive and behavioral impairment in post-institutionalized children adopted from Eastern Europe.

To investigate the role of iron deficiency in general cognitive and behavioral development in post-institutionalized (PI) children during the early post-adoption period. PI children (N = 57) adopted from Eastern Europe or Central Asia (9-46 months of age) were seen at baseline around 1 month after arrival into the US and at follow-up 6 months later. Measures included anthropometry, iron status, the Toddler Behavior Assessment Questionnaire-R (TBAQ-R), the Mullen Scales of Early Learning, and examiner-rated behaviors during testing. 26 % were iron deficient at baseline; 18 % were iron deficient at follow-up. There was a trend for those with iron deficiency at baseline to be more fearful on the TBAQ-R. Those with iron deficiency at follow-up displayed more hyperactivity on both the TBAQ-R and the examiner-rated behaviors. Those with iron deficiency at follow-up were more likely to score below average on the Mullen Early Learning Composite (iron deficient: 80 %; good iron status: 32 %). The association between iron status at follow-up and the Mullen Early Learning Composite was mediated by inattention and hyperactivity behaviors during testing. Iron deficiency is associated with neurobehavioral alterations months after arrival, mediated by the effect on attention and activity levels. Iron status needs to be monitored at least through the first half-year post-adoption, particularly in children exhibiting rapid catch-up growth. Additionally, developmental evaluation is recommended in those with iron deficiency, even in children with good iron status at arrival.

Known and potential roles of transferrin in iron biology.

Transferrin is an abundant serum metal-binding protein best known for its role in iron delivery. The human disease congenital atransferrinemia and animal models of this disease highlight the essential role of transferrin in erythropoiesis and iron metabolism. Patients and mice deficient in transferrin exhibit anemia and a paradoxical iron overload attributed to deficiency in hepcidin, a peptide hormone synthesized largely by the liver that inhibits dietary iron absorption and macrophage iron efflux. Studies of inherited human disease and model organisms indicate that transferrin is an essential regulator of hepcidin expression. In this paper, we review current literature on transferrin deficiency and present our recent findings, including potential overlaps between transferrin, iron and manganese in the regulation of hepcidin expression.

Retinal function and structure in the hypotransferrinemic mouse.

PURPOSE: The iron carrier transferrin is expressed at remarkably high levels in normal retinas and is upregulated during retinal degeneration. The authors characterized the consequences of genetically reduced retinal transferrin production on retinal structure and function. METHODS: Hypotransferrinemic (HPX⁻/⁻) mice treated with weekly intraperitoneal salvage transferrin injections were examined at 1 and 2 months of age. HPX⁻/⁻, HPX⁺/⁻, and wild-type (WT) mice were evaluated by electroretinography, ophthalmoscopy, and histology. Retinal iron content and transferrin levels were measured. RNA levels of genes involved in iron homeostasis and antioxidative response were determined by quantitative PCR. Oxidative injury was assessed by immunostaining for 4-hydroxy-2-nonenal (HNE). RESULTS: At 2 months, dark-adapted, mixed rod-cone response b-wave amplitudes were significantly lower in HPX⁻/⁻ mice than in WT mice (340 ± 112 µV vs. 624 ± 134 µV [mean ± SEM]; P = 0.002). Oscillatory potentials were significantly suppressed in HPX mice, and ophthalmoscopy demonstrated marked retinal pallor. Quantitative immunostaining revealed a 39% reduction of transferrin content in HPX⁻/⁻ compared with WT retinas (P = 0.01). mRNA levels of Tf, Tf receptor, and ceruloplasmin were decreased, whereas mRNA for antioxidant genes were elevated in HPX⁻/⁻ retinas. HNE staining was reduced in mice carrying the mutant HPX allele. Histologic examination demonstrated preserved retinal structure, and retinal iron content was similar across the strains. CONCLUSIONS: Despite the lack of wild-type retinal transferrin production and low levels of retinal transferrin protein, the retinal morphology and retinal iron content in HPX⁻/⁻ mice treated by systemic salvage transferrin injections are normal until age 2 months. However, retinal function and gene expression of some of the iron-associated genes are significantly altered.

Hemojuvelin is essential for transferrin-dependent and transferrin-independent hepcidin expression in mice.

Here we investigate the regulation of hepcidin, a hormone that inhibits dietary iron absorption and macrophage iron recycling, by the serum iron-binding protein transferrin. Mice deficient in transferrin (Tf(hpx/hpx)) and hemojuvelin (Hjv(-/-)), a gene mutated in juvenile hemochromatosis, a disease of hepcidin deficiency and iron overload, were generated. While Tf(hpx/hpx) Hjv(+/+) and Tf(hpx/hpx) Hjv(-/-) phenotypes did not differ markedly, transferrin treatment and RBC transfusions robustly increased hepcidin levels in Tf(hpx/hpx) Hjv(+/+) but not Tf(hpx/hpx) Hjv(-/-)mice. These results suggest that, while hemojuvelin is not essential for the establishment or maintenance of hepcidin deficiency in transferrin-deficient mice, hemojuvelin is essential for transferrin-dependent and transferrin-independent hepcidin expression in conditions of iron overload.

Non-HFE hepatic iron overload.

Numerous clinical entities have now been identified to cause pathologic iron accumulation in the liver. Some are well described and have a verified hereditary basis; in others the genetic basis is still speculative, while in several cases nongenetic iron-loading factors are apparent. The non- HFE hemochromatosis syndromes identifies a subgroup of hereditary iron loading disorders that share with classic HFE-hemochromatosis, the autosomal recessive trait, the pathogenic basis (i.e., lack of hepcidin synthesis or activity), and key clinical features. Yet, they are caused by pathogenic mutations in other genes, such as transferrin receptor 2 ( TFR2), hepcidin ( HAMP), hemojuvelin ( HJV) , and ferroportin ( FPN), and, unlike HFE-hemochromatosis, are not restricted to Caucasians. Ferroportin disease, the most common non- HFE hereditary iron-loading disorder, is caused by a loss of iron export function of FPN resulting in early and preferential iron accumulation in Kupffer cells and macrophages with high ferritin levels and low-to-normal transferrin saturation. This autosomal dominant disorder has milder expressivity than hemochromatosis. Other much rarer genetic disorders are associated with hepatic iron load, but the clinical picture is usually dominated by symptoms and signs due to failure of other organs (e.g., anemia in atransferrinemia or neurologic defects in aceruloplasminemia). Finally, in the context of various necro-inflammatory or disease processes (i.e., chronic viral or metabolic liver diseases), regional or local iron accumulation may occur that aggravates the clinical course of the underlying disease or limits efficacy of therapy.

H-ferritin is the major source of iron for oligodendrocytes.

There is a critical relationship between oligodendrocyte development, myelin production, and iron bioavailability. Iron deficiency leads to hypomyelination both in humans and animal models, and the neurological sequelae of hypomyelination are significant. Therefore, understanding molecular mechanisms of iron import into oligodendrocytes is necessary for devising effective strategies for iron supplementation. Although transferrin has been considered as an essential component of oligodendrocyte media in culture, oligodendrocytes in vivo lack transferrin receptors. We have established that receptors for H-ferritin (HF) exist on cells of oligodendroglial lineage and that uptake of extracellular HF by oligodendrocyte progenitors is via receptor mediated endocytosis. These data strongly argue that ferritin is a major source of iron for oligodendrocytes. In this study, we demonstrate that media deficient in transferrin results in loss of viability of oligodendrocyte progenitors in culture. Cell loss could be prevented by supplementing the media with HF. Moreover, the addition of extracellular HF stimulates development of oligodendrocyte progenitor cells (OPCs) by increasing expression of myelin basic protein (MBP) and olig2 proteins without increasing their proliferation. The effect of HF on the OPCs could be mimicked by addition of membrane permeable 3,5,5-trimethylhexanoyl ferrocene (TMH-Fe) as an iron source to the media, but not membrane-impermeable ferric ammonium citrate. Overall, therefore, our results demonstrate the importance of iron for OPCs viability and differentiation and identify extracellular HF as a critical source of iron for oligodendrocytes. Given that ferritin receptors, but not transferrin receptors can be demonstrated on oligodendrocytes in vivo, the delivery of iron to oligodendrocytes via ferritin may be the more biological relevant delivery system.

Re-evaluation of the dysequilibrium syndrome.

OBJECTIVES: To re-evaluate middle-aged Swedish patients diagnosed with dysequilibrium syndrome (DES) in childhood and to compare their clinical and neuroimaging features to DES with VLDLR gene mutations (DES-VLDR). MATERIALS AND METHODS: Six patients from five families underwent neurological examination and magnetic resonance imaging (MRI) of the brain. Blood samples from the patients were screened for serum carbohydrate-deficient transferrin (s-CDT; disialotransferrin). The very-low-density lipoprotein receptor (VLDLR) gene was sequenced. RESULTS: Five patients had non-progressive cerebellar ataxia (NPCA), dysarthria and short stature. Mental retardation and strabismus, characteristic for DES-VLDLR, were inconsistent among our patients. None of our patients had VLDLR mutations or MRI findings characteristic of DES-VLDLR. MRI findings were variable from a normal cerebellum to marked cerebellar hypoplasia or atrophy and signal intensity changes. One patient was diagnosed with congenital disorder of glycosylation type 1a (CDG-1a). CONCLUSIONS: DES was originally coined on mainly clinical grounds before MRI and specific genetic tests were available, both of which should be used to arrive at an appropriate diagnosis.

Severe hypochromic microcytic anemia in a patient with congenital atransferrinemia.

Congenital atransferrinemia or hypotransferrinemia is a very rare autosomal recessive disorder, characterized by a deficiency of transferrin, resulting in hypochromic, microcytic anemia and hemosiderosis. The authors describe a 10-year-old Iranian girl with hypochromic microcytic anemia. The age presentation of anemia was 3 months. Further evaluations indicate severe hypochromic microcytic anemia with decreased serum levels of iron, TIBC, and increased serum level of ferritin in this patient. The serum level of transferrin was decreased. The diagnosis of atransferrinemia was confirmed. Although atransferrinemia is a rare condition, it should be considered in the cases with hypochromic microcytic anemia, decreased serum levels of iron, TIBC, and increased serum level of ferritin.

Transferrin-a modulates hepcidin expression in zebrafish embryos.

The iron regulatory hormone hepcidin is transcriptionally up-regulated in response to iron loading, but the mechanisms by which iron levels are sensed are not well understood. Large-scale genetic screens in the zebrafish have resulted in the identification of hypochromic anemia mutants with a range of mutations affecting conserved pathways in iron metabolism and heme synthesis. We hypothesized that transferrin plays a critical role both in iron transport and in regulating hepcidin expression in zebrafish embryos. Here we report the identification and characterization of the zebrafish hypochromic anemia mutant, gavi, which exhibits transferrin deficiency due to mutations in transferrin-a. Morpholino knockdown of transferrin-a in wild-type embryos reproduced the anemia phenotype and decreased somite and terminal gut iron staining, while coinjection of transferrin-a cRNA partially restored these defects. Embryos with transferrin-a or transferrin receptor 2 (TfR2) deficiency exhibited low levels of hepcidin expression, however anemia, in the absence of a defect in the transferrin pathway, failed to impair hepcidin expression. These data indicate that transferrin-a transports iron and that hepcidin expression is regulated by a transferrin-a-dependent pathway in the zebrafish embryo.

A new case of human atransferrinemia with a previously undescribed mutation in the transferrin gene.

Hereditary atransferrinemia is a very rare disorder characterized by microcytic anemia and iron overload. It has been reported in only 10 patients in 8 families. The molecular basis of atransferrinemia has been determined in only 3 human cases. We now report a new patient with this rare disorder, who is the first known case in Turkey, the 11th patient reported in the published literature and only the 4th case of human atransferrinemia characterized on a molecular basis. DNA analysis of the serum transferrin gene in the patient revealed a previously undescribed mutation in exon 4, a G-->A transition at cDNA 410(Cys137Tyr). A number of previously known polymorphisms and a previously undescribed mutation at IVS10(-23)C-->T, presumably a polymorphism, were also documented.