Systemic iron homeostasis

Effect of a high-fat diet and iron overload on erythropoiesis in mice

Background

Insulin and iron availability stimulate and regulate erythropoiesis, respectively. The effects of hyperinsulinemia and/or iron overload on erythroid differentiation are unclear.

Methodology

Male C57Bl/6J wild-type (WT) mice were fed a high-fat diet (HFD) (to produce hyperinsulinemia) or a control diet (CD) for varying periods (4-24 weeks). Hepcidin knock-out (Hamp1 -/- ) mice (which are iron-overloaded) were fed CD or HFD for 24 weeks. Terminal erythroid differentiation (TED) in the bone marrow (BM) from these mice was analyzed by flow cytometry. Hematological parameters were estimated in peripheral blood.

Results

HFD-feeding of WT mice did not significantly affect erythroid precursors in the BM or hematological parameters. However, these mice had a significantly higher reticulocyte population in the BM than those fed CD (at all time points studied). Values of hematological parameters were higher in Hamp1 -/- mice than WT mice, at 24 weeks of feeding (irrespective of diet type), indicating increased erythropoiesis. Early erythroid precursors in the BM were higher in HFD-fed Hamp1 -/- mice than those fed CD.

Conclusions

HFD-feeding in WT mice resulted in increases in the proportion of reticulocytes in the bone marrow; maturation of the early erythroid precursors was not significantly affected. In Hamp1 -/- mice, HFD-feeding increased the number of early erythroid precursors.

Anemia in diabetes mellitus: Pathogenetic aspects and the value of early erythropoietin therapy

Anemia is a frequent, yet increasingly recognized, comorbidity in diabetes mellitus (DM), with prevalence often driven by multifactorial mechanisms. Hematinic deficiencies, common in this population, may arise from associated comorbidities or medications, such as metformin, as well as other drugs commonly employed for DM-related conditions. Among contributing factors, diabetic kidney disease (DKD) plays a pivotal role, with anemia developing more frequently and being more pronounced in earlier stages, than in CKD of other causes. This enhanced susceptibility stems primarily from the combined impact of impaired renal oxygen sensing and deficient erythropoietin (EPO) production linked to tubulointerstitial fibrosis. Additional mechanisms comprise glomerular dysfunction, shortened erythrocyte lifespan, uremia-induced bone marrow suppression, and increased bleeding risk. DM is also recognized as a chronic low-grade inflammatory condition, with its inflammatory burden driving iron maldistribution, suppression of erythropoiesis, and resistance to EPO. The diagnostic approach of anemia in DM mirrors that in the general population. Addressing modifiable causes such as hematinic deficiencies, and other chronic conditions, such as DKD and bone marrow disorders, is paramount. In total, the underlying pathophysiology of anemia in DM primarily reflects a state of absolute or relative EPO deficiency and/or diminished bone marrow responsiveness, effectively corresponding to 'anemia of chronic disease. Early initiation of EPO therapy, even in DM patients without overt DKD, may mitigate disease progression and improve outcomes. Future research should focus on diabetes-specific strategies integrating optimal EPO use, potentially implementing targeted management of renal and inflammatory contributors to anemia.

Combinatorial approach to treat iron overload cardiomyopathy in pediatric patients with thalassemia-major: A systematic review and meta-analysis

BACKGROUND

Iron overload cardiomyopathy is a significant cause of morbidity and mortality in transfusion-dependent thalassemia patients. Standard iron chelation therapy is less efficient in alleviating iron accumulation in many organs, especially when iron enters the cells via specific calcium channels.

AIM

To validate our hypothesis that adding amlodipine to the iron chelation regimen is more efficient in alleviating myocardial iron overload.

METHODS

Five databases, including PubMed, Cochrane Library, Embase, ScienceDirect, and ClinicalTrials.gov, were systematically searched, and three randomized controlled trials involving 144 pediatric patients with transfusion-dependent thalassemia were included in our meta-analysis based on the predefined eligibility criteria. The quality of the included studies was assessed based on the Cochrane collaboration tool for bias assessment. The primary outcome assessed was myocardial-T2 and myocardial iron concentration, while the secondary results showed serum ferritin level, liver iron concentration, and treatment adverse outcomes. Weighted mean difference and odds ratio were calculated to measure the changes in the estimated treatment effects.

RESULTS

During the follow-up period, Amlodipine treatment significantly improved cardiac T2 by 2.79 ms compared to the control group [95% confidence interval (CI): 0.34-5.24, P = 0.03, I² = 0%]. Additionally, a significant reduction of 0.31 in myocardial iron concentration was observed with amlodipine treatment compared to the control group [95%CI: -0.38-(-0.25), P < 0.00001, I² = 0%]. Liver iron concentration was slightly lower in the amlodipine group by -0.04 mg/g, but this difference was not statistically significant (95%CI: -0.33-0.24, P = 0.77, I² = 0%). Amlodipine also showed a non-significant trend toward a reduction in serum ferritin levels (-328.86 ng/mL, 95%CI: -1212.34-554.62, P = 0.47, I² = 90%). Regarding safety, there were no significant differences between the groups in the incidence of gastrointestinal upset, hypotension, or lower limb edema.

CONCLUSION

Amlodipine with iron chelation therapy significantly improved cardiac parameters, including cardiac-T2 and myocardial iron, in patients with transfusion-dependent thalassemia without causing significant adverse events but enhancing the efficacy of iron chelation therapy.

Iron homeostasis and ferroptosis in muscle diseases and disorders: mechanisms and therapeutic prospects

The muscular system plays a critical role in the human body by governing skeletal movement, cardiovascular function, and the activities of digestive organs. Additionally, muscle tissues serve an endocrine function by secreting myogenic cytokines, thereby regulating metabolism throughout the entire body. Maintaining muscle function requires iron homeostasis. Recent studies suggest that disruptions in iron metabolism and ferroptosis, a form of iron-dependent cell death, are essential contributors to the progression of a wide range of muscle diseases and disorders, including sarcopenia, cardiomyopathy, and amyotrophic lateral sclerosis. Thus, a comprehensive overview of the mechanisms regulating iron metabolism and ferroptosis in these conditions is crucial for identifying potential therapeutic targets and developing new strategies for disease treatment and/or prevention. This review aims to summarize recent advances in understanding the molecular mechanisms underlying ferroptosis in the context of muscle injury, as well as associated muscle diseases and disorders. Moreover, we discuss potential targets within the ferroptosis pathway and possible strategies for managing muscle disorders. Finally, we shed new light on current limitations and future prospects for therapeutic interventions targeting ferroptosis.

Terahertz Wave Desensitizes Ferroptosis by Inhibiting the Binding of Ferric Ions to the Transferrin

Ferroptosis is a classic type of programmed cell death characterized by iron dependence, which is closely associated with many diseases such as cancer, intestinal ischemic diseases, and nervous system diseases. Transferrin (Tf) is responsible for ferric-ion delivery owing to its natural Fe3+ binding ability and plays a crucial role in ferroptosis. However, Tf is not considered as a classic druggable target for ferroptosis-associated diseases since systemic perturbation of Tf would dramatically disrupt blood iron homeostasis. Here, we reported a nonpharmaceutical, noninvasive, and Tf-targeted electromagnetic intervention technique capable of desensitizing ferroptosis with directivity. First, we revealed that the THz radiation had the ability to significantly decrease binding affinity between the Fe3+ and Tf via molecular dynamics simulations, and the modulation was strongly wavelength-dependent. This result provides theoretical feasibility for the THz modulation-based ferroptosis intervention. Subsequent extracellular and cellular chromogenic activity assays indicated that the THz field at 8.7 μm (i.e., 34.5 THz) inhibited the most Fe3+ bound to the Tf, and the wavelength was in good agreement with the simulated one. Then, functional assays demonstrated that levels of intracellular Fe2+, lipid peroxidation, malondialdehyde (MDA) and cell death were all significantly reduced in cells treated with this 34.5 THz wave. Furthermore, the iron deposition, lipid peroxidation, and MDA in the ferroptosis disease model induced by ischemia-reperfusion injury could be nearly eliminated by the same radiation, validating THz wave-induced desensitization of ferroptosis in vivo. Together, this work provides a preclinical exemplar for electromagnetic irradiation-stimulated desensitization of ferroptosis and predicts an innovative, THz wave-based therapeutic method for ferroptosis-associated diseases in the future.

RNA-Based Biomarkers of Iron Metabolism in Dried Blood Spots for Detecting Recombinant Human Erythropoietin in Doping Control

Erythropoietin (EPO) abuse in sports has been a major challenge in doping analysis for decades. Although the Athlete Biological Passport (ABP) serves as an indirect method for EPO detection, it requires continual improvement to increase its sensitivity and reliability. Biomarkers related to iron metabolism and erythropoiesis as complementary parameters to enhance the ABP hematology module have the potential to improve its ability to detect EPO indirectly. In this study, RNA was extracted from dried blood spot (DBS) samples collected over 28 days (days 0, 1, 3, 5, 7, 9, 11, 13, 21, and 28) following the administration of therapeutic doses of recombinant human EPO (Yibiao, 50 IU/kg per dose, administered subcutaneously twice). The expression of four genes, namely, mitoferrin 1 (MFRN1), ferrochelatase (FECH), ferroportin (FPN), and ferritin heavy chain (FTH), was analyzed. The results revealed significant expression changes, with MFRN1 demonstrating peak increases of 2.43-fold, and presented detection windows extending beyond Day 9, providing greater sensitivity and longer detection windows than traditional ABP parameters do. The integration of MFRN1 into the ABP framework has the potential to increase the detection of EPO misuse in athletes.

Three signalling pathways for iron overload in osteoporosis: a narrative review

Osteoporosis is a metabolic bone disease characterized by a decrease in the amount of bone tissue per unit volume and changes in bone microstructure, often resulting in bone fragility and increased susceptibility to fracture. Iron plays an important role in the normal physiological activities of human body, and its abnormal metabolism is one of the risk factors of osteoporosis. Iron overload, as an abnormality of iron metabolism, has been reported to be associated with osteoporosis in recent years. However, the mechanism of iron overload involved in the process of osteoporosis is not fully understood. In this review, we summarize what we have learned about iron overload-associated bone loss from clinical studies and animal models. Starting from the three signaling pathways of Wnt/β-catenin, BMP/SMADs, PI3K/AKT/mTOR, the mechanism of iron overload affecting the process of osteoporosis was explored, we got the conclusion that iron overload accelerates the process of osteoporosis by inhibiting normal wnt signaling, suppressing the BMP-2/SMADs pathway, down-regulating the PI3K/AKT/mTOR pathway to inhibit bone formation, and destroying the bone strength and load-bearing capacity, which providing a new direction for clinical treatment.

Role of hepcidin on benefits and risks of supplementation with iron syrup and multiple micronutrient powders in Bangladeshi children: a sub-study to a randomized controlled trial

BACKGROUND

Hepcidin can determine individuals' responses to iron supplementation, but limited evidence exists from pediatric trials.

OBJECTIVE

We aimed to examine the influence of hepcidin on the effects of supplementation with iron syrup and multiple micronutrient powders (MNPs) on hemoglobin and ferritin concentrations and incidence of diarrhea in young children.

METHODS

Participants included a subsample of 1281 8-month-old children enrolled in a three-arm, double-blind, double-dummy, individually randomized controlled trial examining the efficacy of 3 months of universal supplementation with daily iron syrup (12.5mg iron), MNPs (containing 12.5mg iron), or placebo in children living in Bangladesh. In all participants at baseline, immediately post-intervention (month 3), and after a further 9 months of follow-up (month 12), serum hepcidin concentrations were measured by ELISA, venous hemoglobin by HemoCue® 301, and incidence of diarrhea by caregiver report. We used a likelihood-based longitudinal data analysis model to examine effect modification from baseline hepcidin on effects of iron syrup or MNPs on hemoglobin and ferritin concentrations and log-binomial model on incidence of diarrhea at months 3 and 12.

RESULTS

Hepcidin modified the effect of MNPs, but not iron syrup, compared to placebo on hemoglobin and ferritin concentrations immediately post intervention. The treatment effect of MNPs compared to placebo in the change from baseline to month 3 was larger among children with low compared to not-low baseline hepcidin (hemoglobin: mean difference 11.6g/L (7.2, 15.9) compared to 4.3 (3.09, 5.7), p-interaction=0.002; ferritin: geometric mean ratio 2.4 (1.6, 3.6) compared to 1.5 (1.3, 1.7), p-interaction=0.024). This effect modification was not sustained at month 12. Hepcidin did not modify effects of either intervention on incidence of diarrhea.

CONCLUSIONS

Immediate effects of MNPs on child hemoglobin and iron status are larger among those with low compared to not-low hepcidin, indicating that pre-intervention screening could help identify those who would benefit most from MNPs.

TRIAL REGISTRATION

ACTRN12617000660381.

5β-hydroxycostic acid from Laggera alata ameliorates sepsis-associated acute kidney injury through its anti-inflammatory and anti-ferroptosis effects via NF-κB and MAPK pathways

ETHNOPHARMACOLOGICAL RELEVANCE

The whole plant of Laggera alata is frequently utilize to remedy inflammatory diseases including nephritis as a traditional Chinese medicine. However, its active ingredients and mechanism of action against sepsis-associated acute kidney injury (SA-AKI) are unknown.

AIM OF THE STUDY

This study aimed to identify active compounds from L. alata that inhibit renal inflammation and ameliorate SA-AKI, and to elucidate their mechanisms of action.

MATERIALS AND METHODS

The chemical constituents were separated from the ethyl acetate layer of L. alata methanol extract by column chromatography over silica gel, medium-pressure liquid chromatography and semipreparative high-performance liquid chromatography. Extensive spectroscopic techniques were applied to determine the chemical structures. The anti-inflammatory efficiency was measured by analyzing the NO production in RAW 264.7 cells. The levels of IL-6, IL-1β, CCL-2 and CCL-5 mRNA were determined by qRT-PCR. Cecal ligation and puncture (CLP) surgery is a frequently applied method to establish the mouse sepsis model. Sepsis was thus induced in mice via CLP. The effect in the treatment of SA-AKI was evaluated by H&E staining and ELISA detection. Western blotting was used to evaluate the protein levels involved in ferroptosis, NF-κB and MAPK signaling pathways.

RESULTS

Twelve compounds were obtained from L.alata including four unreported sesquiterpenoids (1-4). Compound 5 exhibited the most significant inhibitory effect on NO production with the IC50 value of 6.034 μM and could restrain the mRNA expression of inflammatory factors IL-6, IL-1β, CCL-2 and CCL-5. The in vivo results demonstrated that compound 5 alleviated the renal injury by decreasing the serum IL-6, IL-1β, Cr, and BUN levels, reducing the kidney contents of Cys-C and KIM-1, and regulating the kidney levels of MDA, GSH, ferrous iron, GPX4, FTH1, and SLC7A11. Furthermore, Compound 5 also repressed the NF-κB and MAPK pathways in vitro and in vivo.

CONCLUSIONS

This study revealed that compound 5 could ameliorate SA-AKI through exerting its anti-inflammatory and anti-ferroptosis effects via NF-κB and MAPK pathways. The current research supported the traditional use of L.alata in the treatment of renal diseases.

Iron and ferroptosis in kidney disease: molecular and metabolic mechanisms

Maintaining iron homeostasis is necessary for kidney functioning. There is more and more research indicating that kidney disease is often caused by iron imbalance. Over the past decade, ferroptosis' role in mediating the development and progression of renal disorders, such as acute kidney injury (renal ischemia-reperfusion injury, drug-induced acute kidney injury, severe acute pancreatitis induced acute kidney injury and sepsis-associated acute kidney injury), chronic kidney disease (diabetic nephropathy, renal fibrosis, autosomal dominant polycystic kidney disease) and renal cell carcinoma, has come into focus. Thus, knowing kidney iron metabolism and ferroptosis regulation may enhance disease therapy. In this review, we discuss the metabolic and molecular mechanisms of iron signaling and ferroptosis in kidney disease. We also explore the possible targets of ferroptosis in the therapy of renal illness, as well as their existing limitations and future strategies.

Biotin Induces Inactive Chromosome X Reactivation and Corrects Physiopathological Alterations in Beta-Propeller-Protein-Associated Neurodegeneration

Neurodegeneration with brain iron accumulation (NBIA) involves a group of rare neurogenetic disorders often linked with iron overload in the basal nuclei of the brain presenting with spasticity, dystonia, muscle rigidity, neuropsychiatric symptoms, and retinal degeneration. Among NBIA subtypes, beta-propeller-protein-associated neurodegeneration (BPAN) is associated with mutations in the autophagy gene WDR45 (WD repeat domain 45). Previously, we demonstrated that WDR45 mutations in BPAN cellular models impaired autophagy, iron metabolism, and cell bioenergetics. In addition, antioxidant supplementation partially improved cell physiopathology; however, autophagy and cell bioenergetics remained affected. In this work, we explored the possibility of expressing the normal WDR45 allele present in the inactive chromosome X (Xi) of BPAN cells through treatment with epigenetic modulators. The aim of this study was to demonstrate whether biotin, an epigenetic nutrient, was able to restore the expression levels of WDR45 by a mechanism involving Xi reactivation and, consequently, correct BPAN defects. Our study demonstrated that biotin supplementation increases histone biotinylation and allows for the transcription of the WDR45 allele in Xi. Consequently, all physiopathological alterations in BPAN cells were notably corrected. The reactivation of Xi by epigenetic modulators can be a promising approach for the treatment of BPAN and other X-linked diseases.

Synergistic Anti-Ferroptosis with a Minimalistic, Peroxide-Triggered Carbon Monoxide Donor for Parkinson's Disease

Parkinson's disease (PD) is a debilitating neurodegenerative disease, with current treatments primarily focusing on improving dopaminergic activity, providing symptomatic relief but failing to halt disease progression. Ferroptosis drives PD pathogenesis and is a potential therapeutic target. Herein, we introduce a novel peroxide-activated carbon monoxide (CO) donor, PCOD, featuring a streamlined structure designed to potentially enhance blood-brain barrier (BBB) penetration and optimize therapeutic outcomes. PCOD releases CO upon activation by nucleophilic peroxides, e.g., ONOO- and H2O2. This mechanism provides a potent strategy against ferroptosis: first, scavenging peroxides that generate oxidative radicals involved in ferroptosis, and second, CO is proposed to inhibit Fenton chemistry through coordination to Fe2+. In MPTP-treated mice, PCOD prevents dopaminergic neuron loss in the substantia nigra and alleviates PD symptoms. This peroxide-triggered CO release offers a promising and innovative strategy to combat ferroptosis and neurodegeneration in PD.

Genetic Markers of Postmortem Brain Iron

Brain iron (Fe) dyshomeostasis is implicated in neurodegenerative diseases. Genome-wide association studies (GWAS) have identified plausible loci correlated with peripheral levels of Fe. Systemic organs and the brain share several Fe regulatory proteins but there likely exist different homeostatic pathways. We performed the first GWAS of inductively coupled plasma mass spectrometry measures of postmortem brain Fe from 635 Rush Memory and Aging Project (MAP) participants. Sixteen single nucleotide polymorphisms (SNPs) associated with Fe in at least one of four brain regions were measured (p < 5 × 10-8). Promising SNPs (p < 5 × 10-6) were followed up for replication in published GWAS of blood, spleen, and brain imaging Fe traits and mapped to candidate genes for targeted cortical transcriptomic and epigenetic analysis of postmortem Fe in MAP. Results for SNPs previously associated with other Fe traits were also examined. Ninety-eight SNPs associated with postmortem brain Fe were at least nominally (p < 0.05) associated with one or more related Fe traits. Most novel loci identified had no direct links to Fe regulatory pathways but rather endoplasmic reticulum-Golgi trafficking (SORL1, SORCS2, MARCH1, CLTC), heparan sulfate (HS3ST4, HS3ST1), and coenzyme A (SLC5A6, PANK3); supported by nearest gene function and omic analyses. We replicated (p < 0.05) several previously published Fe loci mapping to candidate genes in cellular and systemic Fe regulation. Finally, novel loci (BMAL, COQ5, SLC25A11) and replication of prior loci (PINK1, PPIF, LONP1) lend support to the role of circadian rhythms and mitochondria function in Fe regulation more generally. In summary, we provide support for novel loci linked to pathways that may have greater relevance to brain Fe accumulation; some of which are implicated in neurodegeneration. However, replication of a subset of prior loci for blood Fe suggests that genetic determinants or biological pathways underlying Fe accumulation in the brain are not completely distinct from those of Fe circulating in the periphery.

Rhodamine-based Fluorescent Probe With Quick Response and High Selectivity for Imaging Labile Ferrous Iron in Living Cells and Zebrafish

The transition between its various oxidation states of Iron plays a crucial part in various chemical transformation of cells. Misregulation of iron can give rise to the iron-catalyzed reactive oxygen species disorder which have been linked to a variety of diseases, so it is crucial to monitor the labile iron pool in vivo for clinical diagnosis. According to iron autoxidation and hydrogen abstraction reaction, we reported a novel "off-on" fluorescent probe to response to ferrous (Fe2+) both in solutions and biological systems. The probe responds to Fe2+ with good selectivity toward competing metal ions. What's more, the probe presents significant fluorescent enhancement to Fe2+ in less than 1 min, making real-time sensing in biological system possible. The applications of the probe in bioimaging revealed the changes in labile iron pool by iron autoxidation or diverse stimuli.

Neuroinflammation and iron metabolism after intracerebral hemorrhage: a glial cell perspective

Intracerebral hemorrhage (ICH) is the most common subtype of hemorrhagic stroke causing significant morbidity and mortality. Previously clinical treatments for ICH have largely been based on a single pathophysiological perspective, and there remains a lack of curative interventions. Following the rupture of cerebral blood vessels, blood metabolites activate resident immune cells such as microglia and astrocytes, and infiltrate peripheral immune cells, leading to the release of a series of inflammatory mediators. Degradation of hemoglobin produces large amounts of iron ions, leading to an imbalance of iron homeostasis and the production of large quantities of harmful hydroxyl radicals. Neuroinflammation and dysregulation of brain iron metabolism are both important pathophysiological changes in ICH, and both can exacerbate secondary brain injury. There is an inseparable relationship between brain iron metabolism disorder and activated glial cells after ICH. Glial cells participate in brain iron metabolism through various mechanisms; meanwhile, iron accumulation exacerbates neuroinflammation by activating inflammatory signaling pathways modulating the functions of inflammatory cells, and so on. This review aims to explore neuroinflammation from the perspective of iron metabolism, linking the complex pathophysiological changes, delving into the exploration of treatment approaches for ICH, and offering insights that could enhance clinical management strategies.

Iron improves the antiviral activity of NK cells

Natural killer (NK) cells are innate immune cells that play a crucial role as a first line of defense against viral infections and tumor development. Iron is an essential nutrient for immune cells, but it can also pose biochemical risks such as the production of reactive oxygen species. The importance of iron for the NK cell function has gained increasing recognition. We have previously shown that NK cells require iron to efficiently eliminate virus-infected target cells; however, the impact of nutritional iron deficiency on NK cell function and the therapeutic benefits of iron supplementation remain unclear. Here, we demonstrate that diet-related low iron levels lead to increased retroviral loads due to functional NK cell impairment, while iron supplementation enhances NK cell proliferation, as well as their cytotoxic efficacy. Notably, iron-treated NK cells exhibited significant metabolic changes, including mitochondrial reorganization. Interestingly, although iron supplementation decreased the NK cell's cytokine production, it significantly improved NK cell degranulation and the expression of cytotoxicity-associated proteins. These findings highlight the critical role of iron in maintaining NK cell immunity and suggest that iron supplementation may hold therapeutic potential for supporting the treatment of viral infections and immunodeficiency disorders.

Interplay between energy metabolism and NADPH oxidase-mediated pathophysiology in cardiovascular diseases

Sustained production of reactive oxygen species (ROS) and an imbalance in the antioxidant system have been implicated in the development of cardiovascular diseases (CVD), especially when combined with diabetes, hypercholesterolemia, and other metabolic disorders. Among them, NADPH oxidases (NOX), including NOX1-5, are major sources of ROS that mediate redox signaling in both physiological and pathological processes, including fibrosis, hypertrophy, and remodeling. Recent studies have demonstrated that mitochondria produce more proteins and energy in response to adverse stress, corresponding with an increase in superoxide radical anions. Novel NOX4-mediated modulatory mechanisms are considered crucial for maintaining energy metabolism homeostasis during pathological states. In this review, we integrate the latest data to elaborate on the interactions between oxidative stress and energy metabolism in various CVD, aiming to elucidate the higher incidence of CVD in individuals with metabolic disorders. Furthermore, the correlations between NOX and ferroptosis, based on energy metabolism, are preliminarily discussed. Further discoveries of these mechanisms might promote the development of novel therapeutic drugs targeting NOX and their crosstalk with energy metabolism, potentially offering efficient management strategies for CVD.

The Roles of DMT1 in Inflammatory and Degenerative Diseases

Iron homeostasis is critical for multiple physiological and pathological processes. DMT1, a core iron transporter, is expressed in almost all cells and organs and altered in response to various conditions, whereas, there is few reviews focusing on DMT1 in diseases associated with aberrant iron metabolism. Based on available knowledge, this review described a full view of DMT1 and summarized the roles of DMT1 and DMT1-mediated iron metabolism in the onset and development of inflammatory and degenerative diseases. This review also provided an overview of DMT1-related treatment in these disorders, highlighting its therapeutic potential in chronic inflammatory and degenerative diseases.

Deferiprone protects photoreceptors by inhibiting ferroptosis after experimental retinal detachment

The detachment of the retinal neuroepithelium from the retinal pigment epithelium (RPE), often due to a retinal tear and subsequent subretinal fluid (SRF) accumulation, is a critical factor leading to photoreceptor cells (PR) death and permanent vision impairment in retinal detachment (RD) scenarios. Predicting postoperative visual recovery is challenging, even with surgical reattachment. Research has indicated that increased iron and transferrin (TF) saturation in the vitreous fluid (VF) correlates with poorer visual outcomes, suggesting a potential role for ferroptosis, a form of regulated cell death, in PR following RD. To explore this hypothesis, we analyzed the VF of RD patients for ferroptosis markers, revealing reduced levels of glutathione peroxidase 4 (GPX4), glutathione (GSH), and reduced nicotinamide adenine dinucleotide phosphate (NADPH), alongside elevated levels of Long-chain acyl-CoA synthetase 4(ACSL4), malondialdehyde (MDA), and ferrous iron. We then developed a mouse model to simulate RD and administered the iron chelator deferiprone (DFP) as a treatment. Our findings indicated that DFP mitigated ferroptosis in the retina, thereby preserving retinal architecture and function. Collectively, our study establishes the occurrence of ferroptosis in RD and demonstrates the therapeutic potential of DFP in protecting PR and treating RD.

Iron regulatory protein 1-deficient mice exhibit hypospermatogenesis

Imbalances in testicular iron levels are linked to compromised sperm production and male infertility. Iron regulatory proteins (IRP) 1 and 2 play crucial roles in cellular iron regulation. We investigated the role of IRP1 on spermatogenesis using Irp1-deficient mice (Irp1-/-). Histological analysis of the testis of Irp1-/- mice revealed hypospermatogenesis with a significant reduction in the number of elongated spermatids and daily sperm production compared to wild-type (WT) mice. Flow cytometry of germ cells from WT and Irp1-/- mice showed reduction in spermatocytes and round and elongated spermatids in Irp1-/- mice, which was confirmed by histological and immunofluorescence quantification. Finally, stage VIII of spermatogenesis, crucial for spermatid maturation, was less frequent in Irp1-/- testicular cross-sections. Hypospermatogenesis worsened with age despite unchanged intratesticular iron levels. Mechanistically, this was due to increased oxidative stress indicated by elevated 8-Oxoguanine (8-OxoG) levels, a DNA lesion resulting from reactive oxygen species (ROS). Furthermore, bulk RNA-seq data indicated compromised DNA damage repair and cell cycle processes, including mitosis and meiosis in Irp1-/- mice, which may explain hypospermatogenesis. Our results suggest that IRP1 deletion leads to hypospermatogenesis due to impaired cell cycle progression, decreased DNA damage repair capacity, and oxidative damage. Altogether, this study uncovers a role for IRP1, independent of traditional mechanisms of iron regulation.

Loss of FTH1 Induces Ferritinophagy-Mediated Ferroptosis in Anaemia of Myelodysplastic Syndromes

Single-cell sequencing of lineage negative (Lin-) cells from patients with myelodysplastic syndromes (MDS) revealed a reduction in ferritin heavy chain 1 (FTH1) levels, yet the significance of this decrease in FTH1 in the pathophysiology of MDS remains unclear. In this study, we evaluated the role of FTH1 in patients with MDS. The mRNA expression of FTH1 in GlycoA+ nucleated erythrocytes from MDS patients was significantly lower than that in control group. FTH1 was implicated in both ferritinophagy and ferroptosis in MDS patients, processes that are linked to the development of anaemia. To further validate our observations, we employed shRNA to knock down the FTH1 gene in K562 and SKM1 cells. This knockdown confirmed that the elevated ferroptosis levels observed after FTH1 depletion were indeed due to the induction of ferritinophagy. Hemin stimulation promoted the differentiation of K562 cells, while downregulation of FTH1 gene expression had an impact on erythroid differentiation and haemoglobin synthesis. Taken together, our results suggest that FTH1-mediated ferritinophagy may represent a novel therapeutic target for MDS.

Effects of iron overload in human joint tissue explant cultures and animal models

Osteoarthritis (OA) is a prevalent degenerative joint disease affecting over 530 million individuals worldwide. Recent studies suggest a potential link between iron overload, a condition characterised by the excessive accumulation of iron in the body, and the onset of OA. Iron is essential for various biological processes, and any disruption in its homeostasis can trigger significant health effects, including OA. This study aimed to elucidate the effects of excess iron on joint tissue and the underlying mechanisms associated with excess iron and OA development. Human articular cartilage (n = 6) and synovium (n = 4) were collected from patients who underwent total knee arthroplasty. Cartilage and synovium explants were incubated with a gradually increasing concentration of ferric ammonium citrate for 3 days respectively. The effects of iron homeostasis in tissue explants were analysed using a Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS). To further study the effects of iron excess on OA initiation and development, male 3-week-old Hfe-/- and 5-week-old Tfr2-/- mice, animal models of hereditary haemochromatosis were established. Littermate wild-type mice were fed a high-iron diet to induce dietary overload. All animals were sacrificed at 8 weeks of age, and knee joints were harvested for histological analysis. The LA-ICP-MS analysis unveiled changes in the elemental composition related to iron metabolism, which included alterations in FTH1, FPN1, and HAMP within iron(III)-treated cartilage explants. While chondrocyte viability remained stable under different iron concentrations, ex vivo treatment with a high concentration of Fe3+ increased the catabolic gene expression of MMP13. Similar alterations were observed in the synovium, with added increases in GAG content and inflammation markers. In vivo studies further supported the role of iron overload in OA development as evidenced by spontaneous OA symptoms, proteoglycan loss, increased Mankin scores, synovial thickening, and enhanced immunohistochemical expression of MMP13, ADAMTS5, and P21 in Hfe-/-, Tfr2-/-, and diet-induced iron overload mouse models. Our findings elucidate the specific pathways through which excess iron accelerates OA progression and highlights potential targets for therapeutic intervention aimed at modulating iron levels to mitigate OA symptoms. KEY MESSAGES: Iron overload alters joint iron metabolism, increasing OA markers in cartilage and synovium. High iron levels in mice accelerate OA, highlighting genetic and dietary impacts. Excess iron prompts chondrocyte iron storage response, signalling potential OA pathways. Iron dysregulation linked to increased cartilage degradation and synovial inflammation. Our findings support targeted therapies for OA based on iron modulation strategies.

Assessment of Iron Metabolism and Inflammation in Children with Cerebral Palsy

Background/Objectives: Cerebral palsy (CP) is a motor disorder resulting from brain damage that is common in childhood. Iron is vital for the body's basic functions. Iron metabolism disorders and inflammation contribute to the neurological complications seen in CP. The purpose of this research was to ascertain the association and correlation between markers of inflammation and iron metabolism in children with CP. Methods: A total of 181 children diagnosed with CP and 111 typically developing children were retrospectively included in the study. Demographic data, blood parameters, C-reactive protein, iron, total iron binding capacity, and inflammation markers were evaluated. Results: C-reactive protein (CRP), neutrophil-to-lymphocyte ratio (NLR) and systemic immuno-inflammatory index (SII) levels of CP children were found to be statistically significantly higher than those of control group children (p < 0.05). Iron (Fe) and ferritin levels were lower in the CP group, while total iron binding capacity (TIBC) was higher. Spearman correlation analysis showed significant correlations between iron, ferritin and TIBC and SII. Conclusions: Iron deficiency and chronic inflammation are associated with the pathophysiology of CP in patients with CP, and therefore it is important to monitor markers of iron metabolism and inflammation in these patients.

Deciphering ferroptosis in critical care: mechanisms, consequences, and therapeutic opportunities

Ischemia-reperfusion injuries (IRI) across various organs and tissues, along with sepsis, significantly contribute to the progression of critical illnesses. These conditions disrupt the balance of inflammatory mediators and signaling pathways, resulting in impaired physiological functions in human tissues and organs. Ferroptosis, a distinct form of programmed cell death, plays a pivotal role in regulating tissue damage and modulating inflammatory responses, thereby influencing the onset and progression of severe illnesses. Recent studies highlight that pharmacological agents targeting ferroptosis-related proteins can effectively mitigate oxidative stress caused by IRI in multiple organs, alleviating associated symptoms. This manuscript delves into the mechanisms and signaling pathways underlying ferroptosis, its role in critical illnesses, and its therapeutic potential in mitigating disease progression. We aim to offer a novel perspective for advancing clinical treatments for critical illnesses.

Metal-Dependent Cell Death in Renal Fibrosis: Now and in the Future

Renal fibrosis is a common final pathway underlying nearly almost all progressive kidney diseases. Metal ions are essential trace elements in organisms and are involved in important physiological activities. However, aberrations in intracellular metal ion metabolism may disrupt homeostasis, causing cell death and increasing susceptibility to various diseases. Accumulating evidence suggests a complex association between metal-dependent cell death and renal fibrosis. In this article, we provide a comprehensive overview of the specific molecular mechanisms of metal-dependent cell death and their crosstalk, up-to-date evidence supporting their role in renal fibrosis, therapeutic targeting strategies, and research needs, aiming to offer a rationale for future clinical treatment of renal fibrosis.

Micronutrient Biomarkers and Their Association with Malaria Infection in Children in Buea Health District, Cameroon

Recently malaria and micronutrient deficiencies have become a major worldwide public health problem, particularly in Africa and other endemic countries with children under 5 years old being the most vulnerable. Apart from nutritional problems that cause micronutrient deficiencies, studies have also reported that parasitic infections like malaria can affect the levels of micronutrients. Thus, this research was aimed at assessing the serum levels of micronutrient biomarkers and their association with malaria infection in children under 5 years old in the Buea Health District. Method: This cross-sectional study recruited 80 participants from February to April 2024. The micronutrient biomarkers levels were measured using a Q-7plex Human Micronutrient Measurement Kit. Results: There were changes in serum micronutrient biomarkers levels between malaria infected and healthy children. Ferritin was higher in sick children (23.53 μg/L ± 7.75) than in healthy children (19.07 μg/L ± 3.87), significantly (p < 0.002). The same trend was observed with the soluble transferrin receptor being higher (p < 0.049) in sick children (3.74 mg/L ± 1.92) compared to healthy ones (3.08 mg/L ± 0.64). In addition, the levels of retinol-binding protein 4 and thyroglobulin levels were not significantly different between the sick and healthy children. Therefore, this study revealed that malaria causes alterations in the serum levels of micronutrient biomarkers and consequently affects micronutrient levels in children below the age of 5 in the Buea Health District.

Down-regulation of HSPB1 and MGST1 promote ferroptosis and impact immune infiltration in diabetic cardiomyopathy

Diabetic cardiomyopathy (DCM) is a leading cause of death in diabetic patients. Current therapies do not adequately resolve this problem and focus only on the optimal level of blood glucose for patients. Ferroptosis plays an important role in diabetes mellitus and cardiovascular diseases. However, the role of ferroptosis in DCM remains unclear. Differentially expressed ferroptosis-related genes (DE-FRGs) were identified by intersecting GSE26887 dataset and the Ferroptosis Database (FerrDb). The associations between the DE-FRGs and immune cells in DCM, estimated by CIBERSORTx algorithm, were analyzed. Using ow cytometry (FCM) to evaluated the infiltration of immune cells of myocardial tissues. The expression of DE-FRGs, Glutathione peroxidase 4 (GPX4) and Solute carrier family 7 member 11 (SLC7A11) were examined by real-time quantitative PCR and western blotting. 3 DE-FRGs were identified, which are Heat shock protein family B (small) member 1 (HSPB1), Microsomal glutathione S-transferase 1 (MGST1) and solute carrier family 40 member 1 (SLC40A1) respectively, and they were closely linked to immune cells in DCM. In vivo, the levels of CD8 + T cells, B cells and Treg cells were significantly decreased in the DCM group, while the levels of CD4 + T cells, M1 cells, M2 cells and monocytes were increased. Diabetes significantly decreased HSPB1 and MGST1 levels and increased ferroptosis compared to normal group. Furthermore, ferroptosis inhibitor ferrostatin-1 (Fer-1) alleviated high-fat diet (HFD)-induced cadiomyocyte injury and rescued the ferroptosis. This study suggests that ferroptosis related gene HSPB1 and MGST1 are closely related to immune cell infiltration, which may become therapeutic targets for DCM.

Stealing survival: Iron acquisition strategies of Mycobacteriumtuberculosis

Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis (TB), faces iron scarcity within the host due to immune defenses. This review explores the importance of iron for Mtb and its strategies to overcome iron restriction. We discuss how the host limits iron as an innate immune response and how Mtb utilizes various iron acquisition systems, particularly the siderophore-mediated pathway. The review illustrates the structure and biosynthesis of mycobactin, a key siderophore in Mtb, and the regulation of its production. We explore the potential of targeting siderophore biosynthesis and uptake as a novel therapeutic approach for TB. Finally, we summarize current knowledge on Mtb's iron acquisition and highlight promising directions for future research to exploit this pathway for developing new TB interventions.

Pharmacokinetics and Pharmacodynamics of Rusfertide, a Hepcidin Mimetic, Following Subcutaneous Administration of a Lyophilized Powder Formulation in Healthy Volunteers

BACKGROUND AND OBJECTIVE

Hepcidin, an endogenous peptide hormone, binds to ferroportin and is the master regulator of iron trafficking. Rusfertide, a synthetic peptide, is a potent hepcidin mimetic. Clinical studies suggest rusfertide may be effective in the treatment of polycythemia vera. This study investigated the dose-ranging pharmacokinetics, pharmacodynamics, and safety of a lyophilized formulation of rusfertide.

METHODS

A randomized open-label crossover study was conducted in two groups of healthy adult subjects to evaluate the safety, tolerability, pharmacokinetics, and pharmacodynamics of subcutaneous rusfertide doses that ranged from 10 to 60 mg of a lyophilized formulation and 20 mg of an aqueous prefilled syringe formulation that were used in clinical trials.

RESULTS

Rusfertide showed a rapid initial absorption. Median time to peak plasma concentrations for the lyophilized formulation was 24 h for doses of 10-30 mg and 2-4 h for doses of 45 and 60 mg. Mean terminal half-life ranged from 19.6 to 57.1 h. Rusfertide peak concentration and area under the concentration-time curve increased with an increasing dose, but in a less than dose-proportional manner. Metabolites M4 and M9 were identified as major metabolites. At the rusfertide 20-mg dose, the lyophilized formulation had an area under the concentration-time curve from time zero to infinity approximately 1.5-fold higher than the aqueous formulation. The elimination half-life was comparable for the two formulations. Dose-related decreases in serum iron and transferrin-iron saturation were seen following rusfertide treatment. The majority of treatment-emergent adverse events were mild; treatment-related treatment-emergent adverse events seen in ≥10% of subjects were injection-site erythema and injection-site pruritus.

CONCLUSIONS

Rusfertide was well tolerated; the pharmacokinetic and pharmacodynamic results indicate that lyophilized rusfertide is suitable for once-weekly or twice-weekly administration.

Why cells need iron: a compendium of iron utilisation

Iron deficiency is globally prevalent, causing an array of developmental, haematological, immunological, neurological, and cardiometabolic impairments, and is associated with symptoms ranging from chronic fatigue to hair loss. Within cells, iron is utilised in a variety of ways by hundreds of different proteins. Here, we review links between molecular activities regulated by iron and the pathophysiological effects of iron deficiency. We identify specific enzyme groups, biochemical pathways, cellular functions, and cell lineages that are particularly iron dependent. We provide examples of how iron deprivation influences multiple key systems and tissues, including immunity, hormone synthesis, and cholesterol metabolism. We propose that greater mechanistic understanding of how cellular iron influences physiological processes may lead to new therapeutic opportunities across a range of diseases.

Inhibin subunit beta B (INHBB): an emerging role in tumor progression

The gene inhibin subunit beta B (INHBB) encodes the inhibin βB subunit, which is involved in forming protein members of the transforming growth factor-β (TGF-β) superfamily. The TGF-β superfamily is extensively involved in cell proliferation, differentiation, adhesion, movement, metabolism, communication, and death. Activins and inhibins, which belong to the TGF-β superfamily, were first discovered in ovarian follicular fluid. They were initially described as regulators of pituitary follicle-stimulating hormone (FSH) secretion both in vivo and in vitro. Later studies found that INHBB is expressed not only in reproductive organs such as the ovary, uterus, and testis but also in numerous other organs, including the brain, spinal cord, liver, kidneys, and adrenal glands. This wide distribution implies its involvement in the normal physiological functions of various organs; however, the mechanisms underlying these functions have not yet been fully elucidated. Recent studies suggest that INHBB plays a significant, yet complex role in tumorigenesis. It appears to have dual effects, promoting tumor progression in some contexts while inhibiting it in others, although these roles are not yet fully understood. In this paper, we review the different expression patterns, functions, and mechanisms of INHBB in normal and tumor tissues to illustrate the research prospects of INHBB in tumor progression.

Ferulic Acid Alleviates Lipid and Bile Acid Metabolism Disorders by Targeting FASN and CYP7A1 in Iron Overload-Treated Mice

Iron overload is a common complication in various chronic liver diseases, including non-alcoholic fatty liver disease (NAFLD). Lipid and bile acid metabolism disorders are regarded as crucial hallmarks of NAFLD. However, effects of iron accumulation on lipid and bile acid metabolism are not well understood. Ferulic acid (FA) can chelate iron and regulate lipid and bile acid metabolism, but its potential to alleviate lipid and bile acid metabolism disorders caused by iron overload remains unclear. Here, in vitro experiments, iron overload induced oxidative stress, apoptosis, genomic instability, and lipid deposition in AML12 cells. FA reduced lipid and bile acid synthesis while increasing fatty acid β-oxidation and bile acid export, as indicated by increased mRNA expression of PPARα, Acox1, Adipoq, Bsep, and Shp, and decreased mRNA expression of Fasn, Acc, and Cyp7a1. In vivo experiments, FA mitigated liver injury in mice caused by iron overload, as indicated by reduced AST and ALT activities, and decreased iron levels in both serum and liver. RNA-seq results showed that differentially expressed genes were enriched in biological processes related to lipid metabolism, lipid biosynthesis, lipid storage, and transport. Furthermore, FA decreased cholesterol and bile acid contents, downregulated lipogenesis protein FASN, and bile acid synthesis protein CYP7A1. In conclusion, FA can protect the liver from lipid and bile acid metabolism disorders caused by iron overload by targeting FASN and CYP7A1. Consequently, FA, as a dietary supplement, can potentially prevent and treat chronic liver diseases related to iron overload by regulating lipid and bile acid metabolism.

Nanobiotechnology boosts ferroptosis: opportunities and challenges

Ferroptosis, distinct from apoptosis, necrosis, and autophagy, is a unique type of cell death driven by iron-dependent phospholipid peroxidation. Since ferroptosis was defined in 2012, it has received widespread attention from researchers worldwide. From a biochemical perspective, the regulation of ferroptosis is strongly associated with cellular metabolism, primarily including iron metabolism, lipid metabolism, and redox metabolism. The distinctive regulatory mechanism of ferroptosis holds great potential for overcoming drug resistance-a major challenge in treating cancer. The considerable role of nanobiotechnology in disease treatment has been widely reported, but further and more systematic discussion on how nanobiotechnology enhances the therapeutic efficacy on ferroptosis-associated diseases still needs to be improved. Moreover, while the exciting therapeutic potential of ferroptosis in cancer has been relatively well summarized, its applications in other diseases, such as neurodegenerative diseases, cardiovascular and cerebrovascular diseases, and kidney disease, remain underreported. Consequently, it is necessary to fill these gaps to further complete the applications of nanobiotechnology in ferroptosis. In this review, we provide an extensive introduction to the background of ferroptosis and elaborate its regulatory network. Subsequently, we discuss the various advantages of combining nanobiotechnology with ferroptosis to enhance therapeutic efficacy and reduce the side effects of ferroptosis-associated diseases. Finally, we analyze and discuss the feasibility of nanobiotechnology and ferroptosis in improving clinical treatment outcomes based on clinical needs, as well as the current limitations and future directions of nanobiotechnology in the applications of ferroptosis, which will not only provide significant guidance for the clinical applications of ferroptosis and nanobiotechnology but also accelerate their clinical translations.

Transfusional hemosiderosis in childhood cancer patients and survivors

BACKGROUND

Children treated for cancer are at risk for adverse effects of iron due to transfusions administered during prolonged marrow suppression, which may increase exposure to toxic forms of iron, extrahepatic iron accumulation, and long-term organ damage.

OBJECTIVE

This study aimed to characterize the severity and organ distribution of clinically significant, multisystem iron overload (IO) in an at-risk cohort of pediatric cancer patients.

METHODS

This was a retrospective, cross-sectional study of childhood cancer patients who underwent a magnetic resonance imaging (MRI) due to clinical concern for IO. Data regarding cancer type and treatment, transfusion history, MRI and laboratory results, and treatment for IO were collected. Severity of IO was analyzed by non-parametric tests with respect to clinical characteristics.

RESULTS

Of the 103 patients, 98% of whom had a Cancer Intensity Treatment Rating (ITR-3) of 3 or higher, 53% (54/102) had moderate or greater hepatic siderosis, 80% (77/96) had pancreatic siderosis, 4% (3/80) had cardiac siderosis, and 45% (13/29) had pituitary siderosis and/or volume loss. Pancreatic iron was associated with both cardiac (p = .0043) and pituitary iron (p = .0101). In the 73 off-therapy patients, ferritin levels were lower (p = .0008) with higher correlation with liver iron concentration (LIC) (p = .0016) than on-therapy patients. Fifty-eight subjects were treated for IO.

CONCLUSION

In this heavily treated cohort of pediatric cancer patients, more than 80% had extrahepatic iron loading, which occurs with significant exposure to toxic forms of iron related to decreased marrow activity in setting of transfusions. Further studies should examine the effects of exposure to reactive iron on long-term outcomes and potential strategies for management.

Iron Overload and Abdominal Aortic Aneurysm

Abdominal aortic aneurysm (AAA) is a chronic vascular degenerative disease characterized by progressive segmental dilation of the abdominal aorta. The rupture of an AAA represents a leading cause of death in cardiovascular diseases. Despite numerous experimental and clinical studies examining potential drug targets and therapies, currently there are no pharmaceutical treatment to prevent AAA growth and rupture. Iron is an essential element in almost all living organisms and has important biological functions. Epidemiological studies have indicated that both iron deficiency and overload are associated with adverse clinical outcomes, particularly an increased risk of cardiovascular events. Recent evidence indicates that iron overload is involved in the pathogenesis of abdominal aortic aneurysms. In this review, we provide an overview of the role of iron overload in AAA progression and explore its potential pathological mechanisms. Although the exact molecular mechanisms of iron overload in the development of AAA remain to be elucidated, the inhibition of iron deposition may offer a promising strategy for preventing these aneurysms.

MiRNA Regulates Ferroptosis in Cardiovascular and Cerebrovascular Diseases

Cardiovascular and cerebrovascular diseases (CCVDs) significantly contribute to global mortality and morbidity due to their complex pathogenesis involving multiple biological processes. Ferroptosis is an important physiological process in CCVDs, manifested by an abnormal increase in intracellular iron concentration. MiRNAs, a key class of noncoding RNA molecules, are crucial in regulating CCVDs through pathways like glutathione-glutathione peroxidase 4, glutamate/cystine transport, iron metabolism, lipid metabolism, and other oxidative stress pathways. This article summarizes the progress of miRNAs' regulation on CCVDs, aiming to provide insights for the diagnosis and treatment of CCVDs.

Dose-Dependent Relationship between Iron Metabolism and Perioperative Myocardial Injury in Cardiac Surgery with Cardiopulmonary Bypass: A Retrospective Analysis

INTRODUCTION

We sought to comprehensively explore the potential linear and nonlinear relationship between preoperative iron metabolism and perioperative myocardial injury (PMI) following cardiac surgery with cardiopulmonary bypass (CPB).

METHODS

Patients who underwent cardiac surgery with CPB between December 2018 and April 2021 were retrospectively collected. The measurements of iron metabolism included serum iron (SI), serum ferritin (SF), transferrin (TRF), transferrin saturation (TS), and total iron-binding capacity (TIBC). Logistic regression and restricted cubic spline (RCS) models were used for linear and nonlinear analysis. The primary outcome was PMI with a 100× upper reference limit.

RESULTS

Of 2,420 patients screened, 744 eligible patients were enrolled for the final analysis. The incidence of PMI was 25.7%. No significant linear relationship was observed. In the RCS models adjusted with age (median: 56), female, and history of diabetes, a statistically significant difference was detected between TRF (p for nonlinear 0.0152) or TIBC (p for nonlinear 0.0477) and PMI. The gentle U-shaped relationship observed between TRF, TIBC, and PMI suggests that when TRF and TIBC increase, the risk decreases, reaching its lowest point when TRF = 2.4 and TIBC = 54. Nevertheless, as TRF and TIBC continue to increase, the risk starts to rise again. Subgroup analyses yielded consistent findings, with a notable emphasis on older patients who were more susceptible to variations in iron metabolism.

CONCLUSION

Iron metabolism, including TRF, and TIBC, exhibited a nonlinear relationship with PMI by the RCS model adjusted by age, gender, and history of diabetes.

Direct Ingestion of Oxidized Red Blood Cells (Efferocytosis) by Hepatocytes

Purpose

Both hepatic iron accumulation and hemolysis have been identified as independent prognostic factor in alcohol-related liver disease (ALD); however, the mechanisms still remain poorly understood. We here demonstrate that hepatocytes are able to directly ingest aged and ethanol-primed red blood cells (RBCs), a process termed efferocytosis.

Methods

Efferocytosis of RBCs was directly studied in vitro and observed by live microscopy for real-time visualization. RBCs pretreated with either CuSO4 or ethanol following co-incubation with Huh7 cells and murine primary hepatocytes. Heme oxygenase-1 (HO-1) and other targets were measured by q-PCR.

Results

As shown by live microscopy, oxidized RBCs, but not intact RBCs, are rapidly ingested by both Huh7 cells and murine primary hepatocytes within 10 minutes. In some cases, more than 10 RBCs were seen within hepatocytes, surrounding the nucleus. RBC efferocytosis also rapidly induces HO1, its upstream regulator Nuclear factor erythroid 2-related factor 2 (Nrf2) and ferritin, indicating efficient heme degradation. Preliminary data further suggest that hepatocyte efferocytosis of oxidized RBCs is, at least in part, mediated by scavenging receptors such as ASGPR1. Of note, pretreatment of RBCs with ethanol but also heme and bilirubin also initiated efferocytosis. In a cohort of heavy human drinkers, a significant correlation of hepatic ASGPR1 with the heme degradation pathway was observed.

Conclusion

We here demonstrate that hepatocytes can directly ingest and degrade oxidized RBCs through efferocytosis, a process that can be also triggered by ethanol, heme and bilirubin. Our findings are highly suggestive for a novel mechanism of hepatic iron overload in ALD patients.

Image-based quantification of mitochondrial iron uptake via Mitoferrin-2

Iron is a trace element that is critical for most living organisms and plays a key role in a wide variety of metabolic processes. In the mitochondrion, iron is involved in producing iron-sulfur clusters and synthesis of heme and kept within physiological ranges by concerted activity of multiple molecules. Mitochondrial iron uptake is mediated by the solute carrier transporters Mitoferrin-1 (SLC25A37) and Mitoferrin-2 (SLC25A28). While Mitoferrin-1 is mainly involved in erythropoiesis, the cellular function of the ubiquitously expressed Mitoferrin-2 remains less well defined. Furthermore, Mitoferrin-2 is associated with several human diseases, including cancer, cardiovascular and metabolic diseases, hence representing a potential therapeutic target. Here, we developed a robust approach to quantify mitochondrial iron uptake mediated by Mitoferrin-2 in living cells. We utilize HEK293 cells with inducible expression of Mitoferrin-2 and measure iron-induced quenching of rhodamine B[(1,10-phenanthroline-5-yl)-aminocarbonyl]benzyl ester (RPA) fluorescence and validate this assay for medium-throughput screening. This assay may allow identification and characterization of Mitoferrin-2 modulators and could enable drug discovery for this target.

Iron incorporation in red blood cells of pediatric sickle cell anemia: a stable isotope pilot investigation

BACKGROUND/OBJECTIVES

Sickle cell anemia (SCA) is marked by hypoxia, inflammation, and secondary iron overload (IO), which potentially modulate hepcidin, the pivotal hormone governing iron homeostasis. The aim was to evaluate the iron incorporation in red blood cells (RBC) in SCA pediatric patients, considering the presence or absence of IO.

SUBJECTS/METHODS

SCA children (n = 12; SCAtotal) ingested an oral stable iron isotope (57Fe) and iron incorporation in RBC was measured after 14 days. Patients with ≥1000 ng/mL serum ferritin were considered to present IO (SCAio+; n = 4) while the others were classified as being without IO (SCAio-; n = 8). Liver iron concentration (LIC) was determined by Magnetic Resonance Imaging (MRI) T2* method.

RESULTS

The SCAio+ group had lower iron incorporation (mean ± SD: 0.166 ± 0.04 mg; 3.33 ± 0.757%) than SCAio- patients (0.746 ± 0.303 mg; 14.9 ± 6.05%) (p = 0.024). Hepcidin was not different between groups. Iron incorporation was inversely associated with serum ferritin level (SCAtotal group: r = -0.775, p = 0.041; SCAio- group: r = -0.982; p = 0.018) and sickle hemoglobin (HbS) presented positive correlation with iron incorporation (r = 0.991; p = 0.009) in SCAio- group. LIC was positively associated with ferritin (SCAtotal: r = 0.921; p = 0.026) and C reactive protein (SCAio+: r = 0.999; p = 0.020).

CONCLUSION

SCAio+ group had lower iron incorporation in RBC than SCAio- group, suggesting that they may not need to reduce their intake of iron-rich food, as usually recommended. Conversely, a high percentage of HbS may indirectly exacerbate hypoxia and seems to increase iron incorporation in RBC.

TRIAL REGISTRATION

This trial was registered at www.ensaiosclinicos.gov.br . Identifier RBR-4b7v8pt.

Astragaloside IV attenuates ferroptosis and protects against iron overload-induced retinal injury

Retinal injury may be exacerbated by iron overload. Astragaloside IV (AS-IV) has potential applications in the food and healthcare industry to promote eye health. We sought to determine the mechanisms responsible for the protective effects of AS-IV on photoreceptor and retinal pigment epithelium cell death induced by iron overload. We conducted in vitro and in vivo experiments involving AS-IV pretreatment. We tested AS-IV for its ability to protect iron-overload mice from retinal injury. In particular, we analyzed the effects of AS-IV on iron overload-induced ferroptosis in 661W and ARPE-19 cells. AS-IV not only attenuated iron deposition and retinal injury in iron-overload mice but also effectively reduced iron overload-induced ferroptotic cell death in 661W and ARPE-19 cells. AS-IV effectively prevented ferroptosis by inhibiting iron accumulation and lipid peroxidation. In addition, inhibiting nuclear factor erythroid 2-related factor 2 (Nrf2) eliminated the protective effect of AS-IV against ferroptosis. The results suggest that ferroptosis might be a significant cause of retinal cell death associated with iron overload. AS-IV provides protection from iron overload-induced ferroptosis, partly by activating the Nrf2 signaling pathway.

Momelotinib in myelofibrosis and beyond: a comprehensive review of therapeutic insights in hematologic malignancies

Myelofibrosis (MF), a complex hematological malignancy, presents a diverse array of symptoms, including anemia, constitutional symptoms, bone marrow insufficiency, and splenomegaly. The latter, often necessitating blood transfusions, poses an essential obstacle to MF management. While conventional approaches predominantly involve the use of JAK inhibitors, the potential for exacerbating anemia introduces complexity to the treatment. Nonetheless, Momelotinib stands out as a promising pharmaceutical compound with the potential to revolutionize the field. Momelotinib is an ACVR1 antagonist and a dual inhibitor of the JAK1 and JAK2 enzymes. By targeting MF's hematological and fibrotic aspects, Momelotinib influences iron metabolism by regulating hepcidin. This results in reduced hepcidin expression and increased iron availability, ultimately leading to improved anemia and reduced dependency on blood transfusion. This study aims to provide a concise overview of the pathogenesis of MF and elucidate the mechanism of action of Momelotinib. Subsequently, our review offers a practical summary encompassing the effects of Momelotinib in monotherapy, combined comparative drug therapy, and its associated side effects. Additionally, we explore the application of Momelotinib in other cancer types and investigate predictors for treatment success. Furthermore, we examine the utilization of Momelotinib in patients with liver and kidney failure.

Lack of Hfe and TfR2 in Macrophages Impairs Iron Metabolism in the Spleen and the Bone Marrow

Iron is a vital element involved in a plethora of metabolic activities. Mammalian systemic iron homeostasis is mainly modulated by hepcidin, the synthesis of which is regulated by a number of proteins, including the hemochromatosis-associated proteins Hfe and Transferrin Receptor 2 (TfR2). Macrophages play versatile functions in iron homeostasis by storing iron derived from the catabolism of erythrocytes and supplying iron required for erythropoiesis. The absence of Hfe in macrophages causes a mild iron deficiency in aged mice and leads to an overproduction of the iron exporter Ferroportin 1 (Fpn1). Conversely, TfR2 gene silencing in macrophages does not influence systemic iron metabolism but decreases transcription of the macrophage Fpn1 in adult mice and modulates their immune response. This study investigated cellular and systemic iron metabolism in adult and aged male mice with macrophage-specific Hfe and TfR2 silencing (double knock-out, DKO). Serum iron parameters were significantly modified in aged animals, and significant differences were found in hepatic hepcidin transcription at both ages. Interestingly, splenic iron content was low in adult DKOs and splenic Fpn1 transcription was significantly increased in DKO animals at both ages, while the protein amount does not reflect the transcriptional trend. Additionally, DKO macrophages were isolated from mice bone marrow (BMDMs) and showed significant variations in the transcription of iron genes and protein amounts in targeted mice compared to controls. Specifically, Tranferrin Receptor 1 (TfR1) increased in DKO adult mice BMDMs, while the opposite is observed in the cells of aged DKO mice. Fpn1 transcript was significantly decreased in the BMDMs of adult DKO mice, while the protein was reduced at both ages. Lastly, a significant increase in Erythropoietin production was evidenced in aged DKO mice. Overall, our study reveals that Hfe and TfR2 in macrophages regulate hepatic Hepc production and affect iron homeostasis in the spleen and BMDMs, leading to an iron deficiency in aged animals that impairs their erythropoiesis.

Cadmium in Market Pork Kidneys: A Study on Cadmium Bioavailability and the Health Effects Based on Mouse Models

Edible offal of farmed animals can accumulate cadmium (Cd). However, no studies have investigated Cd bioavailability and its health effects. Here, based on mouse models, market pork kidney samples exhibited high Cd relative bioavailability of 74.5 ± 11.2% (n = 26), close to 83.8 ± 7.80% in Cd-rice (n = 5). This was mainly due to high vitamin D3 content in pork kidney, causing 1.7-2.3-fold up-regulated expression of duodenal Ca transporter genes in mice fed pork kidney compared to mice fed Cd-rice, favoring Cd intestinal absorption via Ca transporters. However, although pork kidney was high in Cd bioavailability, subchronic low-dose (5% in diet) consumption of two pork kidney samples having 0.48 and 0.97 μg Cd g-1 dw over 35 d did not lead to significant Cd accumulation in the tissue of mice fed Cd-free rice but instead remarkably decreased Cd accumulation in the tissue of mice fed Cd-rice (0.48 μg Cd g-1) by ∼50% and increased abundance of gut probiotics (Faecalibaculum and Lactobacillus). Overall, this study contributed to our understanding of the bioavailability and health effects associated with Cd in edible offal, providing mechanistic insights into pork kidney consumption safety based on Cd bioavailability.

Prolactin Drives Iron Release from Macrophages and Uptake in Mammary Cancer Cells through CD44

Iron is an essential element for human health. In humans, dysregulated iron homeostasis can result in a variety of disorders and the development of cancers. Enhanced uptake, redistribution, and retention of iron in cancer cells have been suggested as an "iron addiction" pattern in cancer cells. This increased iron in cancer cells positively correlates with rapid tumor growth and the epithelial-to-mesenchymal transition, which forms the basis for tumor metastasis. However, the source of iron and the mechanisms cancer cells adopt to actively acquire iron is not well understood. In the present study, we report, for the first time, that the peptide hormone, prolactin, exhibits a novel function in regulating iron distribution, on top of its well-known pro-lactating role. When stimulated by prolactin, breast cancer cells increase CD44, a surface receptor mediating the endocytosis of hyaluronate-bound iron, resulting in the accumulation of iron in cancer cells. In contrast, macrophages, when treated by prolactin, express more ferroportin, the only iron exporter in cells, giving rise to net iron output. Interestingly, when co-culturing macrophages with pre-stained labile iron pools and cancer cells without any iron staining, in an iron free condition, we demonstrate direct iron flow from macrophages to cancer cells. As macrophages are one of the major iron-storage cells and it is known that macrophages infiltrate tumors and facilitate their progression, our work therefore presents a novel regulatory role of prolactin to drive iron flow, which provides new information on fine-tuning immune responses in tumor microenvironment and could potentially benefit the development of novel therapeutics.

Daily oral iron supplementation during pregnancy

BACKGROUND

Iron and folic acid supplementation have been recommended in pregnancy for anaemia prevention, and may improve other maternal, pregnancy, and infant outcomes.

OBJECTIVES

To examine the effects of daily oral iron supplementation during pregnancy, either alone or in combination with folic acid or with other vitamins and minerals, as an intervention in antenatal care.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Trials Registry on 18 January 2024 (including CENTRAL, MEDLINE, Embase, CINAHL, ClinicalTrials.gov, WHO's International Clinical Trials Registry Platform, conference proceedings), and searched reference lists of retrieved studies.

SELECTION CRITERIA

Randomised or quasi-randomised trials that evaluated the effects of oral supplementation with daily iron, iron + folic acid, or iron + other vitamins and minerals during pregnancy were included.

DATA COLLECTION AND ANALYSIS

Review authors independently assessed trial eligibility, ascertained trustworthiness based on pre-defined criteria, assessed risk of bias, extracted data, and conducted checks for accuracy. We used the GRADE approach to assess the certainty of the evidence for primary outcomes. We anticipated high heterogeneity amongst trials; we pooled trial results using a random-effects model (average treatment effect).

MAIN RESULTS

We included 57 trials involving 48,971 women. A total of 40 trials compared the effects of daily oral supplements with iron to placebo or no iron; eight trials evaluated the effects of iron + folic acid compared to placebo or no iron + folic acid. Iron supplementation compared to placebo or no iron Maternal outcomes: Iron supplementation during pregnancy may reduce maternal anaemia (4.0% versus 7.4%; risk ratio (RR) 0.30, 95% confidence interval (CI) 0.20 to 0.47; 14 trials, 13,543 women; low-certainty evidence) and iron deficiency at term (44.0% versus 66.0%; RR 0.51, 95% CI 0.38 to 0.68; 8 trials, 2873 women; low-certainty evidence), and probably reduces maternal iron-deficiency anaemia at term (5.0% versus 18.4%; RR 0.41, 95% CI 0.26 to 0.63; 7 trials, 2704 women; moderate-certainty evidence), compared to placebo or no iron supplementation. There is probably little to no difference in maternal death (2 versus 4 events, RR 0.57, 95% CI 0.12 to 2.69; 3 trials, 14,060 women; moderate-certainty evidence). The evidence is very uncertain for adverse effects (21.6% versus 18.0%; RR 1.29, 95% CI 0.83 to 2.02; 12 trials, 2423 women; very low-certainty evidence) and severe anaemia (Hb < 70 g/L) in the second/third trimester (< 1% versus 3.6%; RR 0.22, 95% CI 0.01 to 3.20; 8 trials, 1398 women; very low-certainty evidence). No trials reported clinical malaria or infection during pregnancy. Infant outcomes: Women taking iron supplements are probably less likely to have infants with low birthweight (5.2% versus 6.1%; RR 0.84, 95% CI 0.72 to 0.99; 12 trials, 18,290 infants; moderate-certainty evidence), compared to placebo or no iron supplementation. However, the evidence is very uncertain for infant birthweight (MD 24.9 g, 95% CI -125.81 to 175.60; 16 trials, 18,554 infants; very low-certainty evidence). There is probably little to no difference in preterm birth (7.6% versus 8.2%; RR 0.93, 95% CI 0.84 to 1.02; 11 trials, 18,827 infants; moderate-certainty evidence) and there may be little to no difference in neonatal death (1.4% versus 1.5%, RR 0.98, 95% CI 0.77 to 1.24; 4 trials, 17,243 infants; low-certainty evidence) or congenital anomalies, including neural tube defects (41 versus 48 events; RR 0.88, 95% CI 0.58 to 1.33; 4 trials, 14,377 infants; low-certainty evidence). Iron + folic supplementation compared to placebo or no iron + folic acid Maternal outcomes: Daily oral supplementation with iron + folic acid probably reduces maternal anaemia at term (12.1% versus 25.5%; RR 0.44, 95% CI 0.30 to 0.64; 4 trials, 1962 women; moderate-certainty evidence), and may reduce maternal iron deficiency at term (3.6% versus 15%; RR 0.24, 95% CI 0.06 to 0.99; 1 trial, 131 women; low-certainty evidence), compared to placebo or no iron + folic acid. The evidence is very uncertain about the effects of iron + folic acid on maternal iron-deficiency anaemia (10.8% versus 25%; RR 0.43, 95% CI 0.17 to 1.09; 1 trial, 131 women; very low-certainty evidence), or maternal deaths (no events; 1 trial; very low-certainty evidence). The evidence is uncertain for adverse effects (21.0% versus 0.0%; RR 44.32, 95% CI 2.77 to 709.09; 1 trial, 456 women; low-certainty evidence), and the evidence is very uncertain for severe anaemia in the second or third trimester (< 1% versus 5.6%; RR 0.12, 95% CI 0.02 to 0.63; 4 trials, 506 women; very low-certainty evidence), compared to placebo or no iron + folic acid. Infant outcomes: There may be little to no difference in infant low birthweight (33.4% versus 40.2%; RR 1.07, 95% CI 0.31 to 3.74; 2 trials, 1311 infants; low-certainty evidence), comparing iron + folic acid supplementation to placebo or no iron + folic acid. Infants born to women who received iron + folic acid during pregnancy probably had higher birthweight (MD 57.73 g, 95% CI 7.66 to 107.79; 2 trials, 1365 infants; moderate-certainty evidence), compared to placebo or no iron + folic acid. There may be little to no difference in other infant outcomes, including preterm birth (19.4% versus 19.2%; RR 1.55, 95% CI 0.40 to 6.00; 3 trials, 1497 infants; low-certainty evidence), neonatal death (3.4% versus 4.2%; RR 0.81, 95% CI 0.51 to 1.30; 1 trial, 1793 infants; low-certainty evidence), or congenital anomalies (1.7% versus 2.4; RR 0.70, 95% CI 0.35 to 1.40; 1 trial, 1652 infants; low-certainty evidence), comparing iron + folic acid supplementation to placebo or no iron + folic acid. A total of 19 trials were conducted in malaria-endemic countries, or in settings with some malaria risk. No studies reported maternal clinical malaria; one study reported data on placental malaria.

AUTHORS' CONCLUSIONS

Daily oral iron supplementation during pregnancy may reduce maternal anaemia and iron deficiency at term. For other maternal and infant outcomes, there was little to no difference between groups or the evidence was uncertain. Future research is needed to examine the effects of iron supplementation on other maternal and infant health outcomes, including infant iron status, growth, and development.

Reactive oxygen species regulation by NCF1 governs ferroptosis susceptibility of Kupffer cells to MASH

Impaired self-renewal of Kupffer cells (KCs) leads to inflammation in metabolic dysfunction-associated steatohepatitis (MASH). Here, we identify neutrophil cytosolic factor 1 (NCF1) as a critical regulator of iron homeostasis in KCs. NCF1 is upregulated in liver macrophages and dendritic cells in humans with metabolic dysfunction-associated steatotic liver disease and in MASH mice. Macrophage NCF1, but not dendritic cell NCF1, triggers KC iron overload, ferroptosis, and monocyte-derived macrophage infiltration, thus aggravating MASH progression. Mechanistically, elevated oxidized phospholipids induced by macrophage NCF1 promote Toll-like receptor (TLR4)-dependent hepatocyte hepcidin production, leading to increased KC iron deposition and subsequent KC ferroptosis. Importantly, the human low-functional polymorphic variant NCF190H alleviates KC ferroptosis and MASH in mice. In conclusion, macrophage NCF1 impairs iron homeostasis in KCs by oxidizing phospholipids, triggering hepatocyte hepcidin release and KC ferroptosis in MASH, highlighting NCF1 as a therapeutic target for improving KC fate and limiting MASH progression.

Transfusion-related cost offsets and time burden in patients with myelofibrosis on momelotinib vs. danazol from MOMENTUM

Aim: To estimate projected US-based cost and time burden for patients with myelofibrosis and anemia treated with momelotinib compared with danazol.Methods: Cost and time burden were calculated based on the transfusion status of patients in the MOMENTUM trial and estimates extracted from previous studies.Results: Reductions in transfusion associated with momelotinib are projected to result in cost and time savings compared with danazol in transfusion-dependent and transfusion-independent/requiring patients with myelofibrosis, respectively: annual medical costs ($53,143 and $46,455 per person), outpatient transfusion costs ($42,021 and $8,370 per person) and annual time savings (173 and 35 h per person).Conclusion: Fewer transfusions with momelotinib are projected to result in cost and time savings in patients with myelofibrosis and anemia compared with danazol.

Reduced Plasma Bone Morphogenetic Protein 6 Levels in Sepsis and Septic Shock Patients

Infectious diseases are associated with low iron levels and the induction of hepcidin, the primary protein regulating cellular iron export. Bone morphogenetic protein 6 (BMP6), a key regulator of hepcidin expression, has not yet been analyzed in the plasma of patients with systemic inflammatory response syndrome (SIRS) or sepsis. An analysis of 38 SIRS, 39 sepsis, and 78 septic shock patients revealed similar levels of BMP6 in sepsis and septic shock, which were lower compared to patients with SIRS and healthy controls. Plasma BMP6 levels did not correlate with procalcitonin and C-reactive protein levels in patients with SIRS or sepsis/septic shock. Neither bacterial nor SARS-CoV-2 infections affected plasma BMP6 levels. There was no difference in BMP6 levels between ventilated and non-ventilated patients, or between patients with and without dialysis. Vasopressor therapy did not alter BMP6 levels. Survivors had plasma BMP6 levels similar to non-survivors. Due to the high variability of plasma BMP6 levels, these analyses have limited clinical relevance. Iron, ferritin, and transferrin levels were known in at least 50% of patients but did not correlate with plasma BMP6 levels. In conclusion, this study showed normal BMP6 plasma levels in SIRS, which are reduced in patients with sepsis and septic shock. This suggests that the commonly observed increase in hepcidin levels and the decline in iron levels in SIRS, sepsis, and septic shock are not due to higher BMP6.

Alisma Orientalis Extract Ameliorates Hepatic Iron Deregulation in MAFLD Mice via FXR-Mediated Gene Repression

Iron is a vital trace element for our bodies and its imbalance can lead to various diseases. The progression of metabolic-associated fatty liver disease (MAFLD) is often accompanied by disturbances in iron metabolism. Alisma orientale extract (AOE) has been reported to alleviate MAFLD. However, research on its specific lipid metabolism targets and its potential impact on iron metabolism during the progression of MAFLD remains limited. To establish a model of MAFLD, mice were fed either a standard diet (CON) or a high-fat diet (HFD) for 9 weeks. The mice nourished on the HFD were then randomly assigned to the HF group and the HFA group, with the HFA group receiving AOE by gavage on a daily basis for 13 weeks. Supplementation with AOE remarkably reduced overabundant lipid accumulation in the liver and restored the iron content of the liver. AOE partially but significantly reversed dysregulated lipid metabolizing genes (SCD1, PPAR γ, and CD36) and iron metabolism genes (TFR1, FPN, and HAMP) induced by HFD. Chromatin immunoprecipitation assays indicated that the reduced enrichment of FXR on the promoters of SCD1 and FPN genes induced by HFD was significantly reversed by AOE. These findings suggest that AOE may alleviate HFD-induced disturbances in liver lipid and iron metabolism through FXR-mediated gene repression.