Mechanisms of iron loading and toxicity

Melatonin Supplementation Alleviates Bone Mineral Density Decline and Circulating Oxidative Stress in Iron-Overloaded Thalassemia Patients

Thalassemia patients often exhibit low bone mineral density (BMD). The iron overload associated with thalassemia elevates oxidative stress levels, leading to reduced BMD. Melatonin improves BMD in postmenopausal osteopenia, however, its effect on BMD in thalassemia patients with iron overload has not been investigated. A randomized controlled study was conducted at Hematology Clinic, Faculty of Medicine, Chiang Mai University. Thalassemia patients with osteopenia and iron overloaded condition, as indicated by BMD Z-score <-2 at l-spine, femoral neck, or total hip, and serum ferritin level > 500 μg/L were recruited in this study. Patients were randomized to receive either melatonin 20 mg/day or placebo at bedtime for 12 months. BMD was re-evaluated 12 months after interventions. Bone turnover markers (BTM), malondialdehyde (MDA as an oxidative stress marker), and pain scores were assessed at baseline, 6, and 12 months. The outcomes, including BMD, BTM, MDA, and pain scores, were evaluated in all patients. Forty-one thalassemia patients (18 males) were enrolled in the study and randomly assigned to either the melatonin group (n = 21) or the placebo group (n = 20). Characteristics of patients were not differences between groups. Mean age was 30.8 ± 6.2 years old. Thirty-three patients (80.4%) were transfusion-dependent patients. At 12 months, mean BMD at l-spine in melatonin group was not significantly different from placebo group (p = 0.069). However, l-spine BMD at 12 months in the melatonin group was significantly greater than baseline (p = 0.029). Serum levels of P1NP and MDA were significantly reduced at 6 months compared to baseline following melatonin treatment. The melatonin group experienced a notable decrease in back pain scores after 12 months compared to the initial measurements. 20 mg daily melatonin supplementation for 12 months alleviated l-spine BMD loss in iron-overloaded thalassemia with low BMD. Melatonin also significantly reduced circulating oxidative stress and mitigated back pain in these patients.

Characteristics and outcome of 73 dogs with iron EDTA molluscicide ingestion in Melbourne, Australia (2013-2019)

INTRODUCTION

The objective of this study was to describe the clinical features, treatments and outcomes of dogs with iron ethylenediaminetetraacetate (EDTA) molluscicide ingestion. We aimed to identify potential predictors of serum iron concentration >54 μmol/L; a cut-off recommended for initiating treatment of human iron toxicosis.

METHODS

Medical records across four veterinary hospitals (2013-2019) for dogs with known or suspected iron EDTA molluscicide ingestion were reviewed for signalment, clinical signs, clinicopathological data, treatment regimens and outcomes. Clinical signs of dogs with serum iron concentrations either below or above a cut-off of 54 μmol/L were compared using Fisher's exact test. Association between serum iron and urine discolouration was tested using logistic regression.

RESULTS

Seventy-three dogs were included. The most frequent characteristic was abnormal faeces (n = 47, 64%) as determined by rectal examination, with more dogs that had serum iron >54 μmol/L showing this clinical sign (24/35), compared to dogs with serum iron <54 μmol/L (4/13) (P = 0.025). Clinicopathologic abnormalities included increased base excess (n = 20/49, 20%), hyperglycaemia (n = 13/57, 23%) and hyperlactataemia (n = 12/57, 21%). Fifty-four dogs received deferoxamine chelation (74%), during which 25/42 (60%) dogs had discoloured urine despite all dogs having subsequent iron concentrations <54 μmol/L. Admission serum iron concentration was associated with urine discolouration during hospitalisation (odds ratio 1.046, 95% confidence interval 1.008-1.107, P = 0.011). Sixty-nine dogs (95%) survived to discharge, with 10 dogs (14%) transferred to another veterinarian.

CONCLUSIONS

Iron EDTA molluscicide ingestion caused predominantly gastrointestinal clinical signs, and abnormal faeces, as well as urine discolouration during chelation therapy, which may indicate an elevation of serum iron concentration on presentation. Outcome was excellent.

First report of iron-overload myopathy due to secondary hemochromatosis in a dog

IMPORTANCE

Hemochromatosis is rare in domestic animals, and iron-induced myopathy has not been reported in veterinary medicine. This case is the first report of iron-overload myopathy owing to hemochromatosis in a dog.

CASE PRESENTATION

A 9-year-old spayed female Donggyeong dog presented with severe forelimb lameness. Necropsy revealed an enlarged liver and hemorrhagic lesions in the forelimb muscle. Microscopy showed iron components accumulation in multiple organs, including the liver, forelimb skeletal muscle, spleen, lymph node, and kidney. Prussian blue staining identified iron deposits in both macrophages and parenchymal cells, indicating that the iron accumulation was acquired rather than hereditary. Furthermore, iron components were observed within muscle fibers, accompanied by severe atrophy and myositis.

CONCLUSIONS AND RELEVANCE

Severe necrosis and mild fibrosis were observed in the liver and forelimb skeletal muscles. Based on histological analysis, we diagnosed iron overload myopathy by secondary hemochromatosis. Secondary hemochromatosis with severe muscle atrophy and myositis is very rare, and this is the first report of iron-overload myopathy in a dog.

Decoding ferroptosis: transforming orthopedic disease management

As a mechanism of cell death, ferroptosis has gained popularity since 2012. The process is distinguished by iron toxicity and phospholipid accumulation, in contrast to autophagy, apoptosis, and other cell death mechanisms. It is implicated in the advancement of multiple diseases across the body. Researchers currently know that osteosarcoma, osteoporosis, and other orthopedic disorders are caused by NRF2, GPX4, and other ferroptosis star proteins. The effective relief of osteoarthritis symptoms from deterioration has been confirmed by clinical treatment with multiple ferroptosis inhibitors. At the same time, it should be reminded that the mechanisms involved in ferroptosis that regulate orthopedic diseases are not currently understood. In this manuscript, we present the discovery process of ferroptosis, the mechanisms involved in ferroptosis, and the role of ferroptosis in a variety of orthopedic diseases. We expect that this manuscript can provide a new perspective on clinical diagnosis and treatment of related diseases.

Photothermal Iron-Based Riboflavin Microneedles for the Treatment of Bacterial Keratitis via Ion Therapy and Immunomodulation

Bacterial biofilm formation protects bacteria from antibiotics and the immune system, excessive inflammation further complicates treatment. Here, iron-based metal-organic framework (MIL-101)-loaded riboflavin nanoparticles are designed for the therapeutic challenge of biofilm infection and hyperinflammation in bacterial keratitis. Specifically, MIL-101 produces a thermal effect under exogenous near-infrared light irradiation, which synergizes with ferroptosis-like bacterial death induced by iron ions to exert an effective biofilm infection eradication effect. On the other hand, the disintegration of MIL-101 sustains the release of riboflavin, which inhibits the pro-inflammatory response of macrophage over-activation by modulating their phenotypic switch. In addition, to solve the problems of short residence time, poor permeability, and low bioavailability of corneal medication, the MR@MN microneedle patch is further prepared by loading nanoparticles into SilMA hydrogel, which ultimately achieves painless, transepithelial, and highly efficient drug delivery. In vivo and ex vivo experiments demonstrate the effectiveness of this approach in eliminating bacterial infection and promoting corneal healing. Therefore, the MRMN patch, acting as an ocular drug delivery system with the ability of rapid corneal healing, promises a cost-effective solution for the treatment of bacterial keratitis, which may also lead to a new approach for treating bacterial keratitis in clinics.

Isothiocyanate-Based Microemulsions Loaded into Biocompatible Hydrogels as Innovative Biofumigants for Agricultural Soils

Biofumigation was proposed as an alternative to synthetic pesticides for the disinfection of agricultural soils, in view of the biocidal effect of isothiocyanates (ITCs) released by some vegetal species, like Brassicaceae. However, biofumigation also presents limitations; thus, a novel and viable alternative could be the direct introduction of ITCs into agricultural soils as components loaded into biodegradable hydrogels. Thus, in this work, ITCs-based microemulsions were developed, which can be loaded into porous polymer-based hydrogel beads based on sodium alginate (ALG) or sodium carboxymethyl cellulose (CMC). Three ITCs (ethyl, phenyl, and allyl isothiocyanate) and three different surfactants (sodium dodecylsulfate, Brij 35, and Tween 80) were considered. The optimal system was characterized with attenuated ATR-FTIR spectroscopy and differential scanning calorimetry to study how the microemulsion/gels interaction affects the gel properties, such as the equilibrium water content or free water index. Finally, loading and release profiles were studied by means of UV-Vis spectrophotometry. It was found that CMC hydrogel beads showed a slightly more efficient profile of micelles' release in water with respect to ALG beads. For this reason, and due to the enhanced contribution of Fe(III) to their biocidal properties, CMC-based hydrogels are the most promising in view of the application on real agricultural soils.

Oral phytate supplementation on the progression of mild cognitive impairment, brain iron deposition and diabetic retinopathy in patients with type 2 diabetes: a concept paper for a randomized double blind placebo controlled trial (the PHYND trial)

Type 2 diabetes mellitus has a worldwide prevalence of 10.5% in the adult population (20-79 years), and by 2045, the prevalence is expected to keep rising to one in eight adults living with diabetes. Mild cognitive impairment has a global prevalence of 19.7% in adults aged 50 years. Both conditions have shown a concerning increase in prevalence rates over the past 10 years, highlighting a growing public health challenge. Future forecasts indicate that the prevalence of dementia (no estimations done for individuals with mild cognitive impairment) is expected to nearly triple by 2050. Type 2 diabetes mellitus is a risk factor for the development of cognitive impairment, and such impairment increase the likelihood of poor glycemic/metabolic control. High phytate intake has been shown to be a protective factor against the development of cognitive impairment in observational studies. Diary phytate intake might reduce the micro- and macrovascular complications of patients with type 2 diabetes mellitus through different mechanisms. We describe the protocol of the first trial (the PHYND trial) that evaluate the effect of daily phytate supplementation over 56 weeks with a two-arm double-blind placebo-controlled study on the progression of mild cognitive impairment, cerebral iron deposition, and retinal involvement in patients with type 2 diabetes mellitus. Our hypothesis proposes that phytate, by inhibiting advanced glycation end product formation and chelating transition metals, will improve cognitive function and attenuate the progression from Mild Cognitive Impairment to dementia in individuals with type 2 diabetes mellitus and mild cognitive impairment. Additionally, we predict that phytate will reduce iron accumulation in the central nervous system, mitigate neurodegenerative changes in both the central nervous system and retina, and induce alterations in biochemical markers associated with neurodegeneration.

Iron promotes ovarian cancer malignancy and advances platinum resistance by enhancing DNA repair via FTH1/FTL/POLQ/RAD51 axis

Iron is crucial for cell DNA synthesis and repair, but an excess of free iron can lead to oxidative stress and subsequent cell death. Although several studies suggest that cancer cells display characteristics of 'Iron addiction', an ongoing debate surrounds the question of whether iron can influence the malignant properties of ovarian cancer. In the current study, we initially found iron levels increase during spheroid formation. Furthermore, iron supplementation can promote cancer cell survival, cancer spheroid growth, and migration; vice versa, iron chelators inhibit this process. Notably, iron reduces the sensitivity of ovarian cancer cells to platinum as well. Mechanistically, iron downregulates DNA homologous recombination (HR) inhibitor polymerase theta (POLQ) and relieves its antagonism against the HR repair enzyme RAD51, thereby promoting DNA damage repair to resist chemotherapy-induced damage. Additionally, iron tightly regulated by ferritin (FTH1/FTL) which is indispensable for iron-triggered DNA repair. Finally, we discovered that iron chelators combined with platinum exhibit a synergistic inhibitory effect on ovarian cancer in vitro and in vivo. Our findings affirm the pro-cancer role of iron in ovarian cancer and reveal that iron advances platinum resistance by promoting DNA damage repair through FTH1/FTL/POLQ/RAD51 pathway. Our findings highlight the significance of iron depletion therapy, revealing a promising avenue for advancing ovarian cancer treatment.

Cardiac effects of deferasirox in transfusion-dependent patients with myelodysplastic syndromes: TELESTO study

Iron overload from repeated transfusions has a negative impact on cardiac function, and iron chelation therapy may help prevent cardiac dysfunction in transfusion-dependent patients with myelodysplastic syndromes (MDS). TELESTO (NCT00940602) was a prospective, placebo-controlled, randomised study to evaluate the iron chelator deferasirox in patients with low- or intermediate-1-risk MDS and iron overload. Echocardiographic parameters were collected at screening and during treatment. Patients receiving deferasirox experienced a significant decrease in the composite risk of hospitalisation for congestive heart failure (CHF) or worsening of cardiac function (HR = 0.23; 95% CI: 0.05, 0.99; nominal p = 0.0322) versus placebo. No significant differences between the arms were found in left ventricular ejection fraction, ventricular diameter and mass or pulmonary artery pressure. The absolute number of events was low, but the enrolled patients were younger than average for patients with MDS, with no serious cardiac comorbidities and a modest cardiovascular risk profile. These results support the effectiveness of deferasirox in preventing cardiac damage caused by iron overload in this patient population. Identification of patients developing CHF is challenging due to the lack of distinctive echocardiographic features. The treatment of iron overload may be important to prevent cardiac dysfunction in these patients, even those with moderate CHF risk.

Synthesis of iron-boride/carbon-nitride composites and their applications in chemodynamic therapy

Chemodynamic therapy (CDT) is an emerging treatment strategy that inhibits tumor growth by catalyzing the generation of reactive oxygen species (ROS), such as hydroxyl radicals (•OH), using specific nanomaterials. Herein, we have developed a new class of iron-based nanomaterials, i.e., iron-based borides (FeB), using the superchaotropic effect of a boron cluster (closo-[B12H12]2-) and organic ligands, followed by high-temperature calcination. Experimental data and theoretical calculations revealed that FeB nanoparticles exhibit a Fenton-like effect, efficiently decomposing hydrogen peroxide into •OH and thus increasing the concentration of ROS. FeB nanomaterials demonstrate excellent catalytic performance, efficiently generate ROS, and exert significant antitumor effects in cell experiments and animal models. Therefore, FeB nanomaterials have considerable potential for application in tumor treatment and offer new insights for the development of novel and efficient cancer therapy strategies.

Applications of Boron Cluster Supramolecular Frameworks as Metal-Free Chemodynamic Therapy Agents for Melanoma

Chemodynamic therapy (CDT) is a highly targeted approach to treat cancer since it converts hydrogen peroxide into harmful hydroxyl radicals (OH·) through Fenton or Fenton-like reactions. However, the systemic toxicity of metal-based CDT agents has limited their clinical applications. Herein, a metal-free CDT agent: 2,4,6-tri(4-pyridyl)-1,3,5-triazine (TPT)/ [closo-B12 H12 ]2- (TPT@ B12 H12 ) is reported. Compared to the traditional metal-based CDT agents, TPT@B12 H12 is free of metal avoiding cumulative toxicity during long-term therapy. Density functional theory (DFT) calculation revealed that TPT@B12 H12 decreased the activation barrier more than 3.5 times being a more effective catalyst than the Fe2+ ion (the Fenton reaction), which decreases the barrier about twice. Mechanismly, the theory calculation indicated that both [B12 H12 ]-· and [TPT-H]2+ have the capacity to decompose hydrogen into 1 O2 , OH·, and O2 -· . With electron paramagnetic resonance and fluorescent probes, it is confirmed that TPT@B12 H12 increases the levels of 1 O2 , OH·, and O2 -· . More importantly, TPT@B12 H12 effectively suppress the melanoma growth both in vitro and in vivo through 1 O2 , OH·, and O2 -· generation. This study specifically highlights the great clinical translational potential of TPT@B12 H12 as a CDT reagent.

Development of an iron overload HepG2 cell model using ferrous ammonium citrate

Cell-based iron overload models provide tremendous utility for the investigations into the pathogenesis of different diseases as well as assessing efficacy of various therapeutic strategies. In the literature, establishing such models vary widely with regards to cell lines, iron source, iron treatment conditions and duration. Due to this diversity, researchers reported significant differences in the measured outcomes, either in cellular function or response to a stimulus. Herein, we report the process required to establish an iron overload HepG2 cell model to achieve a consistent and reproducible results such that the literature can strive towards a consensus. Iron loading in cells was achieved with 50 μM of iron every 24 h for 2 days, followed by an additional 24 h of maintenance in fresh media. We demonstrated that iron overloaded cells had significantly increased ROS generation, labile and total iron whilst having various cellular functions resemble cells without iron overload. The present report addresses key pitfalls with regards to the lack of consensus currently present in the literature.

Nutritional Considerations for the Vegan Athlete

Accepting a continued rise in the prevalence of vegan-type diets in the general population is also likely to occur in athletic populations, it is of importance to assess the potential impact on athletic performance, adaptation, and recovery. Nutritional consideration for the athlete requires optimization of energy, macronutrient, and micronutrient intakes, and potentially the judicious selection of dietary supplements, all specified to meet the individual athlete's training and performance goals. The purpose of this review is to assess whether adopting a vegan diet is likely to impinge on such optimal nutrition and, where so, consider evidence based yet practical and pragmatic nutritional recommendations. Current evidence does not support that a vegan-type diet will enhance performance, adaptation, or recovery in athletes, but equally suggests that an athlete can follow a (more) vegan diet without detriment. A clear caveat, however, is that vegan diets consumed spontaneously may induce suboptimal intakes of key nutrients, most notably quantity and/or quality of dietary protein and specific micronutrients (eg, iron, calcium, vitamin B12, and vitamin D). As such, optimal vegan sports nutrition requires (more) careful consideration, evaluation, and planning. Individual/seasonal goals, training modalities, athlete type, and sensory/cultural/ethical preferences, among other factors, should all be considered when planning and adopting a vegan diet.

Lipid peroxidation mediates the association between iron overload and liver injury: cross-sectional and longitudinal analyses in general Chinese urban adults

Iron overload has been associated with acute/chronic organ failure, but whether iron overload induces liver injury remains unclear. The objectives of this study were to assess the relationship between urinary iron and serum alanine aminotransferase (ALT, a biomarker for liver injury), and investigate the potential mediating roles of lipid peroxidation and oxidative DNA damage in such association. Levels of urinary iron, serum ALT, and urinary biomarkers of lipid peroxidation (8-iso-prostaglandin-F_2α [8-iso-PGF_2α]) and oxidative DNA damage (8-hydroxy-deoxyguano-sine [8-OHdG]) were measured among 5386 observations of 4220 participants from the Wuhan-Zhuhai cohort. The relationships of urinary iron with serum ALT and risk of hyperALT were evaluated by linear mixed model and logistic regression model, respectively. The mediating roles of 8-iso-PGF_2α and 8-OHdG were assessed by mediation analyses. This cross-sectional analysis found that urinary iron was positively associated with ALT (β = 0.032; 95% CI: 0.020, 0.044) and hyperALT prevalence (OR = 1.127; 95% CI: 1.065, 1.192). After 3 years of follow-up, participants with persistent high iron levels had increased risk of developing hyperALT (RR = 3.800; 95% CI: 1.464, 9.972) when compared with those with persistent low iron levels. In addition, each 1% increase in urinary iron was associated with a 0.146% (95% CI: 0.128%, 0.164%) increase and a 0.192% (95% CI: 0.154%, 0.229%) increase in 8-iso-PGF_2α and 8-OHdG, respectively. Urinary 8-iso-PGF_2α (β = 0.056; 95% CI: 0.039, 0.074) was positively associated with ALT, while the association between 8-OHdG and ALT was insignificant. Furthermore, increased 8-iso-PGF_2α significantly mediated 22.48% of the urinary iron-associated ALT increment. Our study demonstrated that iron overload was significantly associated with liver injury, which was partly mediated by lipid peroxidation. Controlling iron intake and regulating lipid peroxidation may help in preventing liver injury.

Kinetic aspects of iron(III)-chelation therapy with deferasirox (DFX) revealed by the solvolytic dissociation rate of the Fe(III)-DFX complex estimated with capillary electrophoretic reactor

Capillary electrophoresis was used to estimate the solvolytic dissociation rate (k_d) of metal complexes of deferasirox (DFX, H₃L), a drug used to treat iron overload. Inert Co^IIIL₂^3- did not dissociate. The estimated k_d value for Fe^IIIL₂^3- was (2.7 ± 0.3) × 10^-4 s^-1 (298 K, pH 7.4). The k_d values of other complexes (Al^IIIL₂^3-, Ni^IIL₂^4-, and Mn^IIL^-) were in the range 10^-3-10^-4 s^-1. In contrast, Zn^IIL^- and Cu^IIL^- were too labile to allow k_d estimation. The fact that the half-life of Fe^IIIL₂^3- (43.3 min) is shorter than the blood half-life of DFX (8-16 h) implies that the blood concentration of DFX should be high enough to prevent dissociation of Fe^IIIL₂^3-. The possibility of a safer iron-chelation therapy that avoids excretion of other essential metal ions such as Zn^II is discussed, highlighting the importance of selectivity in terms of kinetic stability.

The Chelating Ability of Plant Polyphenols Can Affect Iron Homeostasis and Gut Microbiota

In the past decades, many studies have widely examined the effects of dietary polyphenols on human health. Polyphenols are well known for their antioxidant properties and for their chelating abilities, by which they can be potentially employed in cases of pathological conditions, such as iron overload. In this review, we have highlighted the chelating abilities of polyphenols, which are due to their structural specific sites, and the differences for each class of polyphenols. We have also explored how the dietary polyphenols and their iron-binding abilities can be important in inflammatory/immunomodulatory responses, with a special focus on the involvement of macrophages and dendritic cells, and how they might contribute to reshape the gut microbiota into a healthy profile. This review also provides evidence that the axes “polyphenol–iron metabolism–inflammatory responses” and “polyphenol–iron availability–gut microbiota” have not been very well explored so far, and the need for further investigation to exploit such a potential to prevent or counteract pathological conditions.

Iron; Benefits or threatens (with emphasis on mechanism and treatment of its poisoning)

Iron is a necessary biological element and one of the richest in the human body, but it can cause changes in cell function and activity control. Iron is involved in a wide range of oxidation - reduction activities. Whenever iron exceeds the cellular metabolic needs, its excess causes changes in the products of cellular respiration, such as superoxide, hydrogen peroxide and hydroxyl. The formation of these compounds causes cellular toxicity. Lack of control over reactive oxygen species causes damages to DNA, proteins, and lipids. Conversely, superoxide, hydrogen peroxide and hydroxyl are reactive oxygen species, using antioxidants, restoring DNA function, and controlling iron stores lead to natural conditions. Iron poisoning causes clinical manifestations in the gastrointestinal tract, liver, heart, kidneys, and hematopoietic system. When serum iron is elevated, serum iron concentrations, total iron-binding capacity (TIBC) and ferritin will also increase. Supportive care is provided by whole bowel irrigation (WBI), esophagogastroduodenoscopy is required to evaluate mucosal injury and remove undissolved iron tablets. The use of chelator agents such as deferoxamine mesylate, deferasirox, deferiprone, deferitrin are very effective in removing excess iron. Of course, the combined treatment of these chelators plays an important role in increasing iron excretion, and reducing side effects.

Fluorogenic Probes for Intracellular Iron Detection

Iron is a crucial element required to sustain multiple biological processes, including oxygen transport, DNA synthesis, and electron transport. In living cells, iron exists as either ferrous iron (Fe2+) or ferric iron (Fe3+), and its redox forms are regulated by the labile iron pool. Both iron deficiency and excess can lead to a range of pathological conditions, such as anemia, cancer, neurodegenerative disorders, and ischemia and reperfusion injury. Iron overload can cause oxidative damage and even cell death, especially via ferroptosis. Impaired ferroptosis pathways are implicated in the pathogenesis of various diseases and are becoming attractive therapeutic targets. Therefore, developing methods to analyze dynamic iron changes in cells is crucial. In this chapter, we introduce several protocols that use fluorogenic iron probes (e.g., FerroFarRed, Calcein-AM, and FRET iron probe 1) to measure intracellular iron content.

Remarkable Plasticity of Bone Iron Homeostasis in Hibernating Daurian Ground Squirrels (Spermophilus dauricus) May Be Involved in Bone Maintenance

Iron overload is an independent risk factor for disuse osteoporosis. Hibernating animals are natural models of anti-disuse osteoporosis; however, whether iron metabolism is involved in bone adaptation and maintenance during hibernation is unclear. To investigate this question, Daurian ground squirrels (Spermophilus dauricus) (n = 5-6/group) were used to study changes in bone iron metabolism and its possible role in anti-disuse osteoporosis during hibernation. Iron content in the femur and liver first decreased in the torpor group (vs. summer group, -66.8% and -25.8%, respectively), then recovered in the post-hibernation group, suggesting remarkable plasticity of bone iron content. The expression of ferritin in the femur and hepcidin in the liver also initially decreased in the torpor group (vs. summer group, -28.5% and -38.8%, respectively), then increased in the inter-bout arousal (vs. torpor group, 126.2% and 58.4%, respectively) and post-hibernation groups (vs. torpor group, 153.1% and 27.1%, respectively). In conclusion, bone iron metabolism in hibernating Daurian ground squirrels showed remarkable plasticity, which may be a potential mechanism to avoid disuse bone loss during extended periods of inactivity. However, the specific location of iron during low-iron hibernation and the source of iron in post-hibernation recovery need to be further explored.

Nano-formulations in treatment of iron deficiency anaemia: An overview

BACKGROUND

Iron deficiency anaemia (IDA) is a significant challenge to global health. The absorption and bioavailability depend on the delivery vehicle being used. Ferrous sulphate is a drug of choice for IDA but leads to frequent gastrointestinal tract side effects that force the patient to discontinue the treatment. Gastrointestinal side effects result from converting bivalent iron into trivalent iron accompanied by reactive oxygen species (ROS) formation. Due to lower absorption, oral preparations of trivalent iron are recommended in patients with intolerance to ferrous sulphate. Nanosized iron preparation can resolved these concerns. The particle size of iron salts has been observed to have a significant impact on iron absorption. The surface area of iron compounds is increased by reducing their particle size, which improves their solubility in gastric juice and boosts their absorption. Sucrosomial iron, ferric citrate complexes, and ferric maltol are some of the novel iron preparations that ensure high bioavailability and good tolerance in chronic kidney disease, congestive heart failure, and inflammatory bowel disease. However, the parenteral route of administration of iron is unacceptable to most patients. Moreover, it leads to high free iron levels in circulation, resulting in ROS generation.

CONCLUSION

This article provides an informative summary of iron deficiency anaemia causes and treatment through nanoformulations and literature and in-depth patent analysis.

Mitochondrial iron metabolism and neurodegenerative diseases

Iron is a key element for mitochondrial function and homeostasis, which is also crucial for maintaining the neuronal system, but too much iron promotes oxidative stress. A large body of evidence has indicated that abnormal iron accumulation in the brain is associated with various neurodegenerative diseases such as Huntington's disease, Alzheimer's disease, Parkinson's disease, and Friedreich's ataxia. However, it is still unclear how irregular iron status contributes to the development of neuronal disorders. Hence, the current review provides an update on the causal effects of iron overload in the development and progression of neurodegenerative diseases and discusses important roles of mitochondrial iron homeostasis in these disease conditions. Furthermore, this review discusses potential therapeutic targets for the treatments of iron overload-linked neurodegenerative diseases.

High Dietary Iron Has a Greater Impact on Brain Iron Homeostasis and Cognitive Function in Old Compared with Young C57BL/6J Male Mice

BACKGROUND

Brain iron accumulation is a feature of Alzheimer disease (AD) but whether a chronic dietary iron overload contributes to AD induction is unknown. We previously showed that young mice fed a high iron diet did not display cognitive impairment despite the AD pathological markers in hippocampus.

OBJECTIVES

We aim to compare the impact of high dietary iron on brain pathologic changes and cognitive function in young and old mice.

METHODS

Male C57BL/6J mice at 1 mo and 13 mo of age were fed with either a control diet (66 mg Fe/kg; Young-Ctrl and Old-Ctrl) or a high iron diet (14 g Fe/kg; Young-High Fe and Old-High Fe) for 7 mo, and outcomes were evaluated at 8 mo and 20 mo of age. Iron concentrations in brain regions were measured by atomic absorption spectrophotometry. Perls's Prussian blue staining and amyloid-β (Aβ) immunostaining were performed. Protein expression in the cerebral cortex and hippocampus was determined by immunoblotting. Superoxide dismutase activity and malondialdehyde concentration were examined. Cognitive functions were tested with the Morris water maze system. Two-factor ANOVA was used to analyze most data.

RESULTS

Compared with Old-Ctrl mice, Old-High Fe mice showed significantly higher iron concentrations in cerebral cortex (60% higher), cerebellum (60% higher), and hippocampus (90% higher), paralleled by lower superoxide dismutase activity and greater malondialdehyde concentration in cerebral cortex and hippocampus and worse cognitive function. In contrast, these variables did not significantly differ between the 2 young groups. Nevertheless, ferritin, phospho-tau, and Aβ1-42 expression in hippocampus and ferritin and Aβ1-42 expression in cerebral cortex were induced by the high iron diet irrespective of the age of mice (40-200% greater).

CONCLUSIONS

High dietary iron induced cognitive defects in old mice but not young mice, suggesting that elderly people should avoid consuming abnormally high concentrations of iron.

Description of the Etiologies, Clinical Characteristics, and Outcomes in Patients with Hyperferritinemia in a Colombian Tertiary Hospital

BACKGROUND

This study analyzes the clinical characteristics, outcomes, and conditions associated with hyperferritinemia (≥5000 ng/mL) in a high-complexity center in Colombia.

METHODS

This retrospective and descriptive study was performed between 2011 and 2020, at the Fundación Valle del Lili, Cali, Colombia, by reviewing medical charts from patients who had serum ferritin measurements equal to or greater than 5000 ng/mL.

RESULTS

We found 350 reports of ferritin values ≥5000 ng/mL, corresponding to 317 patients, with a median ferritin value of 8789 (6001-15 373)  ng/mL. The most frequent etiologies were infection (n = 198, 56.57%), hematologic disorders (n = 104, 29.71%), and blood transfusion (n = 98, 28.00%). These last 2 etiologies cooccurred in 37 (10.57%) cases. The main clinical signs accompanying hyperferritinemia were fever in 199 (56.86%) cases, multiorgan involvement in 125 (35.71%), and hepatomegaly in 95 (27.14%) cases. Ninety-four (29.65%) patients died in the hospital, and 11 (3.47%) died within 30 days after medical discharge, mainly due to infection (n = 51, 48.57%). Intrahospital mortality was associated with significantly higher ferritin levels (10 846, IQR: 6425-23 459) than survival (8452, IQR: 5980-13 932) (P = 0.018).

CONCLUSIONS

Hyperferritinemia is related to many underlying causes, with infection being the principal cause in our cohort, followed by hematologic disorders. Additionally, in-hospital mortality was related to higher ferritin levels.

Role of Iron in the Molecular Pathogenesis of Diseases and Therapeutic Opportunities

Iron is an essential mineral that serves as a prosthetic group for a variety of proteins involved in vital cellular processes. The iron economy within humans is highly conserved in that there is no proper iron excretion pathway. Therefore, iron homeostasis is highly evolved to coordinate iron acquisition, storage, transport, and recycling efficiently. A disturbance in this state can result in excess iron burden in which an ensuing iron-mediated generation of reactive oxygen species imparts widespread oxidative damage to proteins, lipids, and DNA. On the contrary, problems in iron deficiency either due to genetic or nutritional causes can lead to a number of iron deficiency disorders. Iron chelation strategies have been in the works since the early 1900s, and they still remain the most viable therapeutic approach to mitigate the toxic side effects of excess iron. Intense investigations on improving the efficacy of chelation strategies while being well tolerated and accepted by patients have been a particular focus for many researchers over the past 30 years. Moreover, recent advances in our understanding on the role of iron in the pathogenesis of different diseases (both in iron overload and iron deficiency conditions) motivate the need to develop new therapeutics. We summarized recent investigations into the role of iron in health and disease conditions, iron chelation, and iron delivery strategies. Information regarding small molecule as well as macromolecular approaches and how they are employed within different disease pathogenesis such as primary and secondary iron overload diseases, cancer, diabetes, neurodegenerative diseases, infections, and in iron deficiency is provided.

A facile colorimetric method for the quantification of labile iron pool and total iron in cells and tissue specimens

Quantification of iron is an important step to assess the iron burden in patients suffering from iron overload diseases, as well as tremendous value in understanding the underlying role of iron in the pathophysiology of these diseases. Current iron determination of total or labile iron, requires extensive sample handling and specialized instruments, whilst being time consuming and laborious. Moreover, there is minimal to no overlap between total iron and labile iron quantification methodologies-i.e. requiring entirely separate protocols, techniques and instruments. Herein, we report a unified-ferene (u-ferene) assay that enables a 2-in-1 quantification of both labile and total iron from the same preparation of a biological specimen. We demonstrate that labile iron concentrations determined from the u-ferene assay is in agreement with confocal laser scanning microscopy techniques employed within the literature. Further, this assay offers the same sensitivity as the current gold standard, inductively coupled plasma mass spectrometry (ICP-MS), for total iron measurements. The new u-ferene assay will have tremendous value for the wider scientific community as it offers an economic and readily accessible method for convenient 2-in-1 measurement of total and labile iron from biological samples, whilst maintaining the precision and sensitivity, as compared to ICP-MS.

Fighting Iron-Deficiency Anemia: Innovations in Food Fortificants and Biofortification Strategies

Iron deficiency remains one of the main nutritional disorders worldwide and low iron intake and/or bioavailability are currently the major causes of anemia. To fight this public health problem, the scientific challenge is to find an iron form with sufficient bioavailability to increase its levels in humans through food fortification. In turn, biofortification appears as a comparatively advantageous and bearable strategy for the delivery of vitamins and other micronutrients for people without access to a healthy and diverse diet. This approach relies on plant breeding, transgenic techniques, or agronomic practices to obtain a final food product with a higher iron content. It is also known that certain food constituents are able to favor or inhibit iron absorption. The management of these compounds can thus successfully improve the absorption of dietary iron and, ultimately, contribute to fight this disorder present all over the world. This review describes the main causes/manifestations of iron-deficiency anemia, forms of disease prevention and treatment, and the importance of a balanced and preventive diet. A special focus was given to innovative food fortification and biofortification procedures used to improve the iron content in staple food crops.

Antimicrobial Properties of Gallium(III)- and Iron(III)-Loaded Polysaccharides Affecting the Growth of Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa, In Vitro

Antimicrobial resistance (AMR) has become a global concern as many bacterial species have developed resistance to commonly prescribed antibiotics, making them ineffective to treatments. One type of antibiotics, gallium(III) compounds, stands out as possible candidates due to their unique "Trojan horse" mechanism to tackle bacterial growth, by substituting iron(III) in the metabolic cycles of bacteria. In this study, we tested three polysaccharides (carboxymethyl cellulose (CMC), alginate, and pectin) as the binding and delivery agent for gallium on three bacteria (Pseudomonas aeruginosa, Escherichia coli, and Staphylococcus aureus) with a potential bioresponsive delivery mode. Two types of analysis on bacterial growth (minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC)) were carried out while iron(III)-loaded polysaccharide samples were also tested for comparison. The results suggested that gallium showed an improved inhibitory activity on bacterial growth, in particular gallium(III)-loaded carboxymethyl cellulose (Ga-CMC) sample showing an inhibiting effect on growth for all three tested bacteria. At the MIC for all three bacteria, Ga-CMC showed no cytotoxicity effect on human dermal neonatal fibroblasts (HDNF). Therefore, these bioresponsive gallium(III) polysaccharide compounds show significant potential to be developed as the next-generation antibacterial agents with controlled release capability.

Synthesis, characterization, biological activity and electrochemistry studies of iron(III) complex with curcumin-oxime ligand

Iron overload is a key target in drug development. This study aimed to investigate the coordination of Fe(III) ions with a curcumin-oxime ligand that may be used in the treatment of iron overload. The synthesis of the curcumin-oxime ligand and curcumin-oxime-Fe(III) complex was successfully made and characterized in its solid-state and solution-state using FT-IR, UV-Vis, elemental analysis, and 1 H-NMR. However, in this study, we investigated the apoptotic effects of the curcumin-oxime Fe (III) complex on SW480. SW480 cells were exposed to 99.2% medium for 48 hours. After 48 hours, the incubation period, cells were harvested by centrifugation and washed in phosphate-buffered saline (PBS) and lysed in radio-immunoprecipitation assay (RIPA) buffer for 20 minutes and supernatants were taken and pellets were discarded. ELISA test was used to examine the expression, and activity of cleaved caspase-3, Bax, and Bcl-2 proteins in SW480 cells. ELISA test results indicated that the activities of apoptotic proteins Bax, caspase 3 and Bcl-2 in human SW480 cell lines significantly increased in 48 hours treatment. Also, the activity of Bcl-2 was observed to decrease significantly. Catalase activities of the complex were investigated. The findings showed that the complex has a catalase activity. The findings suggest that this type of complex may constitute a new and interesting basis for the future search of new and more potent drugs. The SOD activity of the result showed that the complexes possessed a considerable SOD activity with an IC50 value of 7.685 µM. Also, when compared with the control, a complex increased the SOD levels (P < .05). Electrochemistry studies in the literature have shown that the Fe3+ /Fe2+ couple redox process occurs in low potential. This value is within the range of compounds that are expected to show superoxide dismutase activity. The Ipc /Ipa shows that one electron transport takes place in the complex. Our results suggest that curcumin-oxime may represent a new approach in the treatment of iron overload.

Impact of iron overload on bone remodeling in thalassemia

INTRODUCTION

Iron overload, a state with excessive iron storage in the body, is a common complication in thalassemia patients which leads to multiple organ dysfunctions including the bone. Iron overload-induced bone disease is one of the most common and severe complications of thalassemia including osteoporosis. Currently, osteoporosis is still frequently found in thalassemia even with widely available iron chelation therapy.

STUDY SELECTION

Relevant publications published before December 2019 in PubMed database were reviewed. Both pre-clinical studies and clinical trials were obtained using iron overload, thalassemia, osteoporosis, osteoblast, and osteoclast as keywords.

RESULTS

Increased ROS production is a hallmark of iron overload-induced impaired bone remodeling. At the cellular level, oxidative stress affects bone remodeling by both osteoblast inhibition and osteoclast activation via many signaling pathways. In thalassemia patients, it has been shown that bone resorption was increased while bone formation was concurrently reduced.

CONCLUSION

In this review, reports on the cellular mechanisms of iron overload-associated bone remodeling are comprehensively summarized and presented to provide current understanding this pathological condition. Moreover, current treatments and potential interventions for attenuating bone remodeling in iron overload are also summarized to pave ways for the future discoveries of novel agents that alleviate this condition.

The Central Role of Iron in Human Nutrition: From Folk to Contemporary Medicine

Iron is a fundamental element in human history, from the dawn of civilization to contemporary days. The ancients used the metal to shape tools, to forge weapons, and even as a dietary supplement. This last indication has been handed down until today, when martial therapy is considered fundamental to correct deficiency states of anemia. The improvement of the martial status is mainly targeted with dietary supplements that often couple diverse co-factors, but other methods are available, such as parenteral preparations, dietary interventions, or real-world approaches. The oral absorption of this metal occurs in the duodenum and is highly dependent upon its oxidation state, with many absorption influencers possibly interfering with the intestinal uptake. Bone marrow and spleen represent the initial and ultimate step of iron metabolism, respectively, and the most part of body iron circulates bound to specific proteins and mainly serves to synthesize hemoglobin for new red blood cells. Whatever the martial status is, today’s knowledge about iron biochemistry allows us to embrace exceedingly personalized interventions, which however owe their success to the mythical and historical events that always accompanied this metal.

Differential effects of Fe2+ and Fe3+ on osteoblasts and the effects of 1,25(OH)2D3, deferiprone and extracellular calcium on osteoblast viability under iron-overloaded conditions

One of the potential contributing factors for iron overload-induced osteoporosis is the iron toxicity on bone forming cells, osteoblasts. In this study, the comparative effects of Fe³⁺ and Fe²⁺ on osteoblast differentiation and mineralization were studied in UMR-106 osteoblast cells by using ferric ammonium citrate and ferrous ammonium sulfate as Fe³⁺ and Fe²⁺ donors, respectively. Effects of 1,25 dihydroxyvitamin D₃ [1,25(OH)₂D₃] and iron chelator deferiprone on iron uptake ability of osteoblasts were examined, and the potential protective ability of 1,25(OH)₂D₃, deferiprone and extracellular calcium treatment in osteoblast cell survival under iron overload was also elucidated. The differential effects of Fe³⁺ and Fe²⁺ on reactive oxygen species (ROS) production in osteoblasts were also compared. Our results showed that both iron species suppressed alkaline phosphatase gene expression and mineralization with the stronger effects from Fe³⁺ than Fe²⁺. 1,25(OH)₂D₃ significantly increased the intracellular iron but minimally affected osteoblast cell survival under iron overload. Deferiprone markedly decreased intracellular iron in osteoblasts, but it could not recover iron-induced osteoblast cell death. Interestingly, extracellular calcium was able to rescue osteoblasts from iron-induced osteoblast cell death. Additionally, both iron species could induce ROS production and G0/G1 cell cycle arrest in osteoblasts with the stronger effects from Fe³⁺. In conclusions, Fe³⁺ and Fe²⁺ differentially compromised the osteoblast functions and viability, which can be alleviated by an increase in extracellular ionized calcium, but not 1,25(OH)₂D₃ or iron chelator deferiprone. This study has provided the invaluable information for therapeutic design targeting specific iron specie(s) in iron overload-induced osteoporosis. Moreover, an increase in extracellular calcium could be beneficial for this group of patients.

Oral ferroportin inhibitor VIT-2763: First-in-human, phase 1 study in healthy volunteers

Restriction of iron availability by ferroportin inhibition is a novel approach to treating non‐transfusion‐dependent thalassemia (β‐thalassemia intermedia). This first‐in‐human, Phase I study (https://www.clinicaltrialsregister.eu; EudraCT no. 2017‐003395‐31) assessed the safety, tolerability, pharmacokinetics and pharmacodynamics of single‐ and multiple‐ascending doses (SAD and MAD) of the oral ferroportin inhibitor, VIT‐2763, in healthy volunteers. Participants received VIT‐2763 5/15/60/120/240 mg or placebo in the SAD phase and VIT‐2763 60/120 mg once daily, VIT‐2763 60/120 mg twice daily, or placebo for 7 days in the MAD phase. Seventy‐two participants completed treatment. VIT‐2763 was well tolerated and demonstrated a similar safety profile to the placebo. There were no serious or severe adverse events, or discontinuations due to adverse events. VIT‐2763 absorption was relatively fast, with detectable levels 15 to 30 minutes post‐dose. Following multiple dosing there was no apparent change in absorption and accumulation was minimal. Mean elimination half‐life was 1.9 to 5.3 hours following single dosing, and 2.1 to 3.8 hours on Day 1 and 2.6 to 5.3 hours on Day 7, following repeated dosing. There was a temporary decrease in mean serum iron levels with VIT‐2763 single doses ≥60 mg and all multiple doses; mean calculated transferrin saturation (only assessed following multiple dosing) also temporarily decreased. A shift in mean serum hepcidin peaks followed administration of all iron‐lowering doses of VIT‐2763. This effect was less pronounced after 7 days of multiple dosing (aside from with 120 mg once daily). These results support the initiation of clinical studies in patients with non‐transfusion‐dependent thalassemia and documented iron overload due to ineffective erythropoiesis.

High Dietary Iron Disrupts Iron Homeostasis and Induces Amyloid-β and Phospho-τ Expression in the Hippocampus of Adult Wild-Type and APP/PS1 Transgenic Mice

BACKGROUND

Brain iron deposition is a feature of Alzheimer disease and may contribute to its development. However, the relative contribution of dietary iron remains unclear.

OBJECTIVES

We investigated the impact of high dietary iron on brain pathological changes and cognitive function in adult wild-type (WT) mice and amyloid precursor protein/presenilin 1 (APP/PS1) double transgenic mice.

METHODS

Male WT mice and APP/PS1 mice aged 10 wk were fed either a control diet (66 mg Fe/kg) (WT-Ctrl and APP/PS1-Ctrl) or a high iron diet (14 g Fe/kg) (WT-High Fe and APP/PS1-High Fe) for 20 wk. Iron concentrations in brain regions were measured by atomic absorption spectrophotometry. Brain iron staining and amyloid-β (Aβ) immunostaining were performed. Protein expressions in the hippocampus were determined by immunoblotting. Superoxide dismutase (SOD) activity and malondialdehyde concentration were examined. Cognitive functions were tested with the Morris water maze system.

RESULTS

In the hippocampus, APP/PS1-High Fe mice had significantly higher iron concentration (2.5-fold) and ferritin (2.0-fold) than APP/PS1-Ctrl mice (P < 0.001), and WT-High Fe mice had significantly higher ferritin (2.0-fold) than WT-Ctrl mice (P < 0.001). Interestingly, APP/PS1 mice had significantly higher iron concentration (2-3-fold) and ferritin (2-2.5-fold) than WT mice fed either diet (P < 0.001). Histological analysis indicated that iron accumulated in the hippocampal dentate gyrus region in APP/PS1 mice, consistent with the pattern of Aβ deposition. For both mouse strains, iron treatment induced Aβ and phospho-τ expression (1.5-3-fold) in the hippocampus, but had little impact on oxidative stress and cognitive function. Furthermore, APP/PS1 mice had significantly lower SOD activity and higher malondialdehyde concentration than WT mice in the hippocampus (P < 0.0001), paralleled by apparent cognitive dysfunction.

CONCLUSIONS

Dietary iron overload induces iron disorder and Aβ and phospho-τ expression in the hippocampus of adult WT and APP/PS1 transgenic mice.

Serum Iron Analytes in Healthy and Diseased Florida Manatees (Trichechus manatus latirostris)

Serum iron concentration is usually decreased in true iron deficiency and with inflammatory disease in man and domestic animals. Serum total iron binding capacity (TIBC) may be increased in true iron deficiency and decreased with inflammatory disease. This prospective study was designed to measure serum iron analytes in healthy free-ranging and housed Florida manatees (Trichechus manatus latirostris) of both sexes and various ages and to evaluate the effects of diseases common to manatees on these analytes. Blood samples were collected without anticoagulant from 137 healthy free-ranging manatees, 90 healthy housed manatees and 74 free-ranging diseased manatees, and serum was prepared by centrifugation. Serum iron concentration and unsaturated iron binding capacity were measured colourimetrically, and TIBC and percent transferrin saturation with iron were calculated. Serum amyloid A (SAA) was measured to assist in the health assessment of manatees and provide evidence of inflammation in diseased manatees. Based on the serum iron analytes, iron availability was lower in immature manatees compared with adults, and it was lower in housed manatees compared with free-ranging manatees. In contrast to other mammals studied, serum iron concentration was elevated rather than depressed in late pregnancy. Serum iron concentrations and transferrin saturation with iron percentages were significantly lower, and SAA concentrations were significantly higher, in diseased (ill and injured) manatees compared with healthy manatees. Serum iron concentration and transferrin saturation with iron values were negatively correlated with SAA concentrations, and manatees with the highest SAA concentrations had lower serum TIBC values. These findings indicate that inflammation is the major factor responsible for alterations in iron analytes in diseased manatees. Consequently, hypoferraemia may be used as supportive evidence of inflammatory disease in manatees (unless haemorrhage is also present). A decision threshold of ≤13.8 μmol/l was determined for hypoferraemia using receiver operating curve analysis. Based on studies in man and domestic animals, iron therapy is unnecessary for manatees with hypoferraemia associated with inflammation and has the potential for causing tissue damage and increased susceptibility to bacterial infections.

Protective effect of sestrin2 against iron overload and ferroptosis-induced liver injury

Ferroptosis is the non-apoptotic form of cell death caused by small molecules or conditions that inhibit glutathione biosynthesis or resulting in iron-dependent accumulation of lipid peroxidation by lipid reactive oxygen species (ROS). Sestrin2 (Sesn2), a conserved antioxidant protein, is responsive to various stresses including genotoxic, metabolic, and oxidative stresses and acts to restore homeostatic balance. Sesn2 expression was reported to be regulated via stress-responsive transcription factors including p53, Nrf2, and HIF-1α. However, the role of Sesn2 in regulating ferroptosis is not known. In the current study, we investigated whether ferroptosis inducing compounds including erastin, sorafenib, and buthionine sulfoximine affect Sesn2 expression and the role of Sesn2 in cytoprotection against ferroptosis-mediated cell death. Our data demonstrate that ferroptosis inducers significantly increased Sesn2 in hepatocytes in a dose- and time-dependent manner. Treatment with erastin upregulated Sesn2 mRNA levels and luciferase reporter gene activity, and erastin-mediated Sesn2 induction was transcriptionally regulated by NF-E2-related factor 2 (Nrf2). Furthermore, deletion of the antioxidant response element (ARE) in the Sesn2 promoter or Nrf2 knockout or knockdown abolished erastin-induced Sesn2 expression. In cells expressing Sesn2, erastin-induced cell death, ROS formation, and glutathione depletion were almost completely inhibited compared to that in control cells. Treatment with phenylhydrazine in mice, well-reported iron overload liver injury model, increased ALT and AST levels and altered histological features, which were almost completely inhibited by adenoviral Sesn2 infection. Collectively, our results suggest that ferroptosis-mediated Sesn2 induction is dependent on Nrf2 and plays a protective role against iron overload and ferroptosis-induced liver injury.

Multi-copper ferroxidase deficiency leads to iron accumulation and oxidative damage in astrocytes and oligodendrocytes

Accumulation of iron has been associated with the pathobiology of various disorders of the central nervous system. Our previous work has shown that hephaestin (Heph) and ceruloplasmin (Cp) double knockout (KO) mice induced iron accumulation in multiple brain regions and that this was paralleled by increased oxidative damage and deficits in cognition and memory. In this study, we enriched astrocytes and oligodendrocytes from the cerebral cortex of neonatal wild-type (WT), Heph KO and Cp KO mice. We demonstrated that Heph is highly expressed in oligodendrocytes, while Cp is mainly expressed in astrocytes. Iron efflux was impaired in Cp KO astrocytes and Heph KO oligodendrocytes and was associated with increased oxidative stress. The expression of Heph, Cp, and other iron-related genes was examined in astrocytes and oligodendrocytes both with and without iron treatment. Interestingly, we found that the expression of the mRNA encoding ferroportin 1, a transmembrane protein that cooperates with CP and HEPH to export iron from cells, was positively correlated with Cp expression in astrocytes, and with Heph expression in oligodendrocytes. Our findings collectively demonstrate that HEPH and CP are important for the prevention of glial iron accumulation and thus may be protective against oxidative damage.

Cellular Iron Metabolism and Regulation

Iron is an essential trace element in the human body, but excess iron is toxic as it contributes to oxidative damage. To keep iron concentration within the optimal physiologic range, iron metabolism at the cellular level and the whole systemic level are tightly regulated. Balance of iron homeostasis depends on the expression levels and activities of iron carriers, iron transporters, and iron regulatory and storage proteins. Divalent metal transporter 1 (DMT1) at the apical membrane of intestinal enterocyte brings in non-heme iron from the diet, whereas ferroportin 1 (FPN1) at the basal membrane exports iron into the circulation. Plasma transferrin (Tf) then carries iron to various tissues and cells. After binding to transferrin receptor 1 (TfR1), the complex is endocytosed into the cell, where iron enters the cytoplasm via DMT1 on the endosomal membrane. Free iron is either utilized in metabolic processes, such as synthesis of hemoglobin and Fe-S cluster, or sequestered in the cytosolic ferritin, serving as a cellular iron store. Excess iron can be exported from the cell via FPN1. The liver-derived peptide hepcidin plays a major regulatory role in controlling FPN1 level in the enterocyte, and thus controls the whole-body iron absorption. Inside the cells, iron regulatory proteins (IRPs) modulate the expressions of DMT1, TfR1, ferritin, and FPN1 via binding to the iron-responsive element (IRE) in their mRNAs. Both the release of hepcidin and the IRP-IRE interaction are coordinated with the fluctuation of the cellular iron level. Therefore, an adequate and steady iron supplement is warranted for the utilization of cells around the body. Investigations on the molecular mechanisms of cellular iron metabolism and regulation could advance the fields of iron physiology and pathophysiology.

Polymeric Nanoparticles Enhance the Ability of Deferoxamine To Deplete Hepatic and Systemic Iron

Chelators are commonly used to remove excess iron in iron-loading disorders. Deferoxamine (DFO) is an effective and safe iron chelator but an onerous parenteral administration regimen limits its routine use. To develop more effective methods for delivering iron chelators, we examined whether amphiphilic copolymer nanoparticles (NPs) could deliver DFO more efficiently. Physical characterization showed a uniform and stable preparation of DFO nanoparticles (DFO-NPs) with an average diameter of 105.3 nm. In macrophage (RAW264.7) and hepatoma (HepG2) cell lines, DFO-NPs proved more effective at depleting iron than free DFO. In wild-type mice previously loaded with iron dextran, as well as Hbb ^{th3 /+} and Hfe ^-/- mice, which are predisposed to iron loading, DFO-NPs (40 mg/kg DFO; alternate days; 4 weeks) reduced hepatic iron levels by 71, 46, and 37%, respectively, whereas the equivalent values for free DFO were 53, 7, and 15%. Staining for tissue iron and urinary iron excretion confirmed these findings. Pharmacokinetic analysis showed that NP-encapsulated DFO had a much longer elimination half-life than free DFO (48.63 ± 28.80 vs 1.46 ± 0.59 h), and that DFO-NPs could be readily taken up by tissues and in particular by hepatic Kupffer cells. In vitro, DFO-NPs were less toxic to several cell lines than free DFO, and in vivo they did not elicit any specific inflammatory responses or histological changes. Our results suggest that using a nanoformulation of DFO is a valuable strategy for improving its efficiency as an iron chelator and that this could broaden its clinical use for the treatment of human iron overload disorders.

Deletion of hephaestin and ceruloplasmin induces a serious systemic iron deficiency and disrupts iron homeostasis

Multi-copper ferroxidases (MCFs) play important roles in cellular iron metabolism and homeostasis. In this study, we generated the hephaestin (Heph), ceruloplasmin (Cp) single and Heph/Cp double knockout (KO) mice to investigate the roles of MCFs in iron transport among system and vital organs in mice at 4 weeks and 6 months of age. Compared with wild-type (WT) mice, Heph/Cp mice at both ages presented with severe anemia and significantly lower iron level in the serum and spleen, but with significantly higher iron level in the liver, heart, kidney, and duodenal enterocytes. Furthermore, Heph/Cp mice displayed significantly lower level of hepcidin mRNA and transferrin receptor 1 (TFR1) protein expression, but significantly higher level of ferroportin 1 (FPN1) protein expression in the liver than WT mice at 6 months of age. Liver superoxide dismutase (SOD) and glutathione peroxidase (GPx) enzyme activities were significantly lower in Heph/Cp KO mice than WT mice at 6 months of age. Together, our results suggest that ablation of HEPH and CP could lead to severe systemic iron deficiency and local tissue iron overload, which disrupt the whole body iron homeostasis and impact on tissue functions.

Multi-Copper Ferroxidase-Deficient Mice Have Increased Brain Iron Concentrations and Learning and Memory Deficits

Background

The accumulation of iron occurs in the central nervous system (CNS) in several neurodegenerative diseases. Although multi-copper ferroxidases (MCFs) play an important role in cellular iron metabolism and homeostasis, the mechanism of MCFs in the CNS remains unclear.

Objective

The aim was to study the role of MCFs in CNS iron metabolism and homeostasis by using hephaestin/ceruloplasmin (Heph/Cp) double knockout (KO) mice.

Methods

Heph/Cp double KO male mice were generated by crossing both single KO mice. In Heph/Cp KO and wild-type (WT) control mice at 4 wk and 6 mo of age, iron concentrations of selected brain regions were measured by atomic absorption spectrophotometry, and gene expressions of Heph, Cp, ferroportin 1 (Fpn1) [+ iron responsive element (IRE)], L-ferritin, H-ferritin, transferrin receptor 1 (Tfrc), and divalent metal transporter 1 (Dmt1) (+IRE) were quantitated by quantitative reverse transcriptase-polymerase chain reaction. Brain region L-ferritin protein concentration, superoxide dismutase (SOD), and glutathione peroxidase (GPx) activities and malondialdehyde (MDA) concentration were also determined. Learning and memory abilities in Heph/Cp KO and WT control mice at 6 mo of age were tested by the IntelliCage system (New Behavior).

Results

Iron concentration was significantly higher in Heph/Cp KO mice than in WT control mice at 4 wk of age in the cortex (50%), hippocampus (120%), brainstem (35%), and cerebellum (220%) and at 6 mo of age in the cortex (140%), hippocampus (420%), brainstem (560%), and cerebellum (340%). L-Ferritin and MDA concentrations were significantly higher and SOD and GPx activities were significantly lower in the cortex, hippocampus, brainstem, and cerebellum of KO mice than in those of WT controls at both 4 wk and 6 mo of age. Iron-related gene expressions also differed significantly between groups. Learning and memory deficits occurred in Heph/Cp KO mice at 6 mo of age.

Conclusion

Mutation of both MCFs in mice induces iron accumulation in brain regions, oxidative damage, and learning and memory defects.

Significant Hyperbilirubinemia and Acute Hepatocellular Jaundice in a Pediatric Patient Receiving Deferasirox: A Case Report

Despite a boxed warning, postmarketing reports of deferasirox-associated hepatic injury in patients with chronic transfusions are not well described. Hepatic impairment, including failure, has been reported to occur more frequently in patients older than 55 years and in those with significant comorbidities, including liver cirrhosis and multiorgan failure. In this case report, we describe significant hyperbilirubinemia and acute hepatocellular jaundice related to deferasirox in a 7-year-old female being treated for iron overload secondary to chronic transfusions. This report outlines a unique case without preexisting risk factors in which other causes of liver injury are excluded as defined by the Roussel Uclaf Causality Assessment Method, which indicates a probable score of deferasirox causing the injury.

Experience of hepatitis C virus seroprevalence and its genomic diversity among transfusion-dependent thalassemia patients in a transfusion center

INTRODUCTION:

One of the most common blood-borne transfusion-transmitted diseases is hepatitis C. Patients with a history of multiple blood transfusions are significantly at a greater risk of infection by contaminated blood and blood products. Beta thalassemia major is one such condition where repeated blood transfusions are required for patient management.

MATERIALS AND METHODS:

The present study was conducted to investigate the serological prevalence of hepatitis C virus (HCV), its viremia, and genotype distribution with clinical parameters among multitransfused thalassemic individuals. In this study, a total of 300 patients were screened to detect anti-HCV antibody in serum, along with liver function parameters and genotyping.

RESULTS:

Seventy-five (25%) patients were found to be HCV positive by enzyme-linked immunosorbent assay (ELISA). Among them, 49 (65%) were HCV RNA positive having a significant viral load in their blood and rest 26 (35%) were below detection level, which signify auto clearance of the virus in those patients. According to our study, HCV genotype 3 was the major circulating strain (92.59%) followed by genotype 1. Liver enzymes, such as alanine aminotransferase, aspartate aminotransferase, and total bilirubin, were significantly elevated among HCV seroreactive individuals.

CONCLUSIONS:

This study clearly indicates that the incidence of transfusion-transmitted hepatitis C is high in thalassemia patients, but actual scenario of HCV viremia can only be found by HCV RNA qualitative and quantitative detection method and not by ELISA, is a major concern for this high-risk group of population.

Current understanding of iron homeostasis

Iron is an essential trace element, but it is also toxic in excess, and thus mammals have developed elegant mechanisms for keeping both cellular and whole-body iron concentrations within the optimal physiologic range. In the diet, iron is either sequestered within heme or in various nonheme forms. Although the absorption of heme iron is poorly understood, nonheme iron is transported across the apical membrane of the intestinal enterocyte by divalent metal-ion transporter 1 (DMT1) and is exported into the circulation via ferroportin 1 (FPN1). Newly absorbed iron binds to plasma transferrin and is distributed around the body to sites of utilization with the erythroid marrow having particularly high iron requirements. Iron-loaded transferrin binds to transferrin receptor 1 on the surface of most body cells, and after endocytosis of the complex, iron enters the cytoplasm via DMT1 in the endosomal membrane. This iron can be used for metabolic functions, stored within cytosolic ferritin, or exported from the cell via FPN1. Cellular iron concentrations are modulated by the iron regulatory proteins (IRPs) IRP1 and IRP2. At the whole-body level, dietary iron absorption and iron export from the tissues into the plasma are regulated by the liver-derived peptide hepcidin. When tissue iron demands are high, hepcidin concentrations are low and vice versa. Too little or too much iron can have important clinical consequences. Most iron deficiency reflects an inadequate supply of iron in the diet, whereas iron excess is usually associated with hereditary disorders. These disorders include various forms of hemochromatosis, which are characterized by inadequate hepcidin production and, thus, increased dietary iron intake, and iron-loading anemias whereby both increased iron absorption and transfusion therapy contribute to the iron overload. Despite major recent advances, much remains to be learned about iron physiology and pathophysiology.

Experimental oral iron administration: Histological investigations and expressions of iron handling proteins in rat retina with aging

Iron is implicated in age-related macular degeneration (AMD). The aim of this study was to see if long-term, experimental iron administration with aging modifies retinal and choroidal structures and expressions of iron handling proteins, to understand some aspects of iron homeostasis. Male Wistar rats were fed with ferrous sulphate heptahydrate (500mg/kg body weight/week, oral; elemental iron availability: 20%) from 2 months of age onward until they were 19.5 month-old. At 8, 14 and 20 months of age, they were sacrificed and serum and retinal iron levels were detected by HPLC. Oxidative stress was analyzed by TBARS method. The retinas were examined for cell death (TUNEL), histology (electron microscopy) and the expressions of transferrin, transferrin receptor-1 [TFR-1], H- and L-ferritin. In control animals, at any age, there was no difference in the serum and retinal iron levels, but the latter increased significantly in 14- and 20 month-old iron-fed rats, indicating that retinal iron accumulation proceeds with progression of aging (>14 months). The serum and retinal TBARS levels increased significantly with progression of aging in experimental but not in control rats. There was significant damage to choriocapillaris, accumulation of phagosomes in retinal pigment epithelium and increased incidence of TUNEL+ cells in outer nuclear layer and vacuolation in inner nuclear layer (INL) of 20 month-aged experimental rats, compared to those in age-matched controls. Vacuolations in INL could indicate a long-term effect of iron accumulation in the inner retina. These events paralleled the increased expression of ferritins and transferrin and a decrease in the expression of TFR-1 in iron-fed rats with aging, thereby maintaining iron homeostasis in the retina. As some of these changes mimic with those happening in eyes with AMD, this model can be utilized to understand iron-induced pathophysiological changes in AMD.

Role of iron in the pathogenesis of respiratory disease

Iron is essential for many biological processes, however, too much or too little iron can result in a wide variety of pathological consequences, depending on the organ system, tissue or cell type affected. In order to reduce pathogenesis, iron levels are tightly controlled in throughout the body by regulatory systems that control iron absorption, systemic transport and cellular uptake and storage. Altered iron levels and/or dysregulated homeostasis have been associated with several lung diseases, including chronic obstructive pulmonary disease, lung cancer, cystic fibrosis, idiopathic pulmonary fibrosis and asthma. However, the mechanisms that underpin these associations and whether iron plays a key role in the pathogenesis of lung disease are yet to be fully elucidated. Furthermore, in order to survive and replicate, pathogenic micro-organisms have evolved strategies to source host iron, including freeing iron from cells and proteins that store and transport iron. To counter these microbial strategies, mammals have evolved immune-mediated defence mechanisms that reduce iron availability to pathogens. This interplay between iron, infection and immunity has important ramifications for the pathogenesis and management of human respiratory infections and diseases. An increased understanding of the role that iron plays in the pathogenesis of lung disease and respiratory infections may help inform novel therapeutic strategies. Here we review the clinical and experimental evidence that highlights the potential importance of iron in respiratory diseases and infections.

Neurobehavioural Toxicity of Iron Oxide Nanoparticles in Mice

Iron oxide nanoparticles (Fe₂O₃-NPs) are widely used in various biomedical applications, extremely in neurotheranostics. Simultaneously, Fe₂O₃-NP usage is of alarming concern, as its exposure to living systems causes deleterious effects due to its redox potential. However, study on the neurobehavioural impacts of Fe₂O₃-NPs is very limited. In this regard, adult male mice were intraperitoneally administered with Fe₂O₃-NPs (25 and 50 mg/kg body weight) once a week for 4 weeks. A significant change in locomotor behaviour and spatial memory was observed in Fe₂O₃-NP-treated animals. Damages to blood-brain barrier permeability by Fe₂O₃-NPs and their accumulation in brain regions were evidenced by Evan's blue staining, iron estimation and Prussian blue staining. Elevated nitric oxide, acetylcholinesterase, lactate dehydrogenase leakage and demyelination were observed in the Fe₂O₃-NP-exposed brain tissues. Imbalanced levels of ROS generation and antioxidant defence mechanism (superoxide dismutase and catalase) cause damages to lipids, proteins and DNA. PARP and cleaved caspase 3 expression levels were found to be increased in the Fe₂O₃-NP-exposed brain regions which confirms DNA damage and apoptosis. Thus, repeated Fe₂O₃-NP exposure causes neurobehavioural impairments by nanoparticle accumulation, oxidative stress and apoptosis in the mouse brain.

Quantitative T2* magnetic resonance imaging for renal iron overload assessment: normal values by age and sex

PURPOSE

Few studies of renal iron content have been performed with multiecho gradient-echo (ME-GRE) T2* magnetic resonance imaging (MRI). We assessed the feasibility and reproducibility of ME-GRE T2* MRI for measuring regional and global renal T2* values, and established the lower limits of normal in healthy subjects, also correlating the measured values with age and sex.

METHODS

Twenty consecutive healthy subjects (13 men and 7 women, mean age 29.1 ± 7.2 years, range 19-42 years) underwent MRI examinations using a 1.5 T magnet and an ME-GRE T2* sequence. For each kidney, T2* was measured in anterior, posterolateral, and posteromedial renal parenchymal regions. The mean T2* value was calculated as the average of the two kidneys T2* values.

RESULTS

For the mean kidney T2* value, the coefficients of variation for intra- and inter-operator reproducibility were 1.76% and 6.23%, respectively. The lower limit of normal for the mean kidney T2* value was 31 ms (median 51.39 ± 10.09). There was no significant difference between left and right kidney T2* values (p = 0.578). No significant correlation was found between T2* values and subjects' age or sex.

CONCLUSIONS

Renal ME-GRE T2* appears to be a feasible and reproducible technique. The renal T2* values showed no dependence on sex or age.

Iron and oxidative stress in cardiomyopathy in thalassemia

With repeated blood transfusions, patients with thalassemia major rapidly become loaded with iron, often surpassing hepatic metal accumulation capacity within ferritin shells and infiltrating heart and endocrine organs. That pathological scenario contrasts with the physiological one, which is characterized by an efficient maintenance of all plasma iron bound to circulating transferrin, due to a tight control of iron ingress into plasma by the hormone hepcidin. Within cells, most of the acquired iron becomes protein-associated, as once released from endocytosed transferrin, it is used within mitochondria for the synthesis of protein prosthetic groups or it is incorporated into enzyme active centers or alternatively sequestered within ferritin shells. A few cell types also express the iron extrusion transporter ferroportin, which is under the negative control of circulating hepcidin. However, that system only backs up the major cell regulated iron uptake/storage machinery that is poised to maintain a basal level of labile cellular iron for metabolic purposes without incurring potentially toxic scenarios. In thalassemia and other transfusion iron-loading conditions, once transferrin saturation exceeds about 70%, labile forms of iron enter the circulation and can gain access to various types of cells via resident transporters or channels. Within cells, they can attain levels that exceed their ability to chemically cope with labile iron, which has a propensity for generating reactive oxygen species (ROS), thereby inducing oxidative damage. This scenario occurs in the heart of hypertransfused thalassemia major patients who do not receive adequate iron-chelation therapy. Iron that accumulates in cardiomyocytes forms agglomerates that are detected by T2* MRI. The labile forms of iron infiltrate the mitochondria and damage cells by inducing noxious ROS formation, resulting in heart failure. The very rapid relief of cardiac dysfunction seen after intensive iron-chelation therapy in some patients with thalassemia major is thought to be due to the relief of the cardiac mitochondrial dysfunction caused by oxidative stress or to the removal of labile iron interference with calcium fluxes through cardiac calcium channels. In fact, improvement occurs well before there is any significant improvement in the total level of cardiac iron loading. The oral iron chelator deferiprone, because of its small size and neutral charge, demonstrably enters cells and chelates labile iron, thereby rapidly reducing ROS formation, allowing better mitochondrial activity and improved cardiac function. Deferiprone may also rapidly improve arrhythmias in patients who do not have excessive cardiac iron. It maintains the flux of iron in the direction hemosiderin to ferritin to free iron, and it allows clearance of cardiac iron in the presence of other iron chelators or when used alone. To date, the most commonly used chelator combination therapy is deferoxamine plus deferiprone, whereas other combinations are in the process of assessment. In summary, it is imperative that patients with thalassemia major have iron chelators continuously present in their circulation to prevent exposure of the heart to labile iron, reduce cardiac toxicity, and improve cardiac function.