Iron metabolism and iron disorders revisited in the hepcidin era

Intracellular autoactivation and surface location of hepsin, TMPRSS2, and TMPRSS13

AIMS

Hepsin (HPN), a Type II transmembrane serine protease (TTSP), is involved in hepatocyte metabolism and various diseases. It undergoes autoactivation on the surface of human hepatoma cells, a mechanism not observed in other cell types. This study aims to explore HPN activation and surface expression in endometrial epithelial cells.

MATERIALS AND METHODS

We studied HPN zymogen activation and cell surface expression in human embryonic kidney 293 and endometrial epithelial AN3CA and Ishikawa cells using site-directed mutagenesis, Western blotting, flow cytometry, and immunostaining. Treatments with brefeldin A (BFA) and monensin, along with co-transfection assays, were employed to assess HPN activation and expression before reaching the cell surface. We also analyzed the activation and expression of TMPRSS2 and TMPRSS13 and examined the effect of the serine protease inhibitor HAI-1 on these proteases.

KEY FINDINGS

HPN zymogen autoactivates in the endoplasmic reticulum (ER) and Golgi apparatus. Its active form reduces cell surface expression through trans-autodegradation, a mechanism also applicable to in TMPRSS2 and TMPRSS13. Additionally, HAI-1 interacts with these TTSPs in different ways: it inhibits HPN activation and stabilizes its cell-surface expression; it inhibits TMPRSS2 activation without affecting its cell-surface expression; and it facilitates TMPRSS13 activation, protecting it from degradation and stabilizing its cell surface expression.

SIGNIFICANCE

These results revealed an intracellular autoactivation and expression mechanism of HPN, TMPRSS2, and TMPRSS13, differing from the extracellular activated TTSPs. These findings provide new insights into the diverse mechanisms in regulating TTSP activation, potentially aiding in treating TTSP-related endometrial diseases.

Relationship Between Hepatic Iron Concentration and Glycemic Metabolism, Prediabetes, and Type 2 Diabetes: A Systematic Review

CONTEXT

Emerging research has suggested a potential link between high iron levels, indicated by serum ferritin levels, and the development of type 2 diabetes (T2D). However, the role of hepatic iron concentration (HIC) on T2D development and progression is not well understood.

OBJECTIVES

This study aims to systematically review the literature on HIC and/or the degree of hepatic iron overload (HIO) in individuals with prediabetes and/or diagnosed T2D, and to analyze associations between HIC and markers of glucose metabolism.

DATA SOURCES

The databases Medline, PubMed, Embase, CINAHL, and Web of Knowledge were searched for studies published in English from 1999 to March 2024. This review followed the Preferred Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist.

DATA EXTRACTION

Data were extracted following the established eligibility criteria. Study characteristics and biomarkers related to prediabetes, T2D, and HIO were extracted. The risk of bias was analyzed using the Newcastle-Ottawa Scale. Data were stratified by the exposure and analyzed in subgroups according to the outcome. Data regarding the HIC values in controls, individuals with prediabetes, and individuals with T2D and the association estimates between HIC or HIO and markers of glycemic metabolism, prediabetes, or T2D were extracted.

DATA ANALYSIS

A total of 12 studies were identified, and data from 4110 individuals were analyzed. HIO was not consistently observed in prediabetic/T2D populations; however, elevated HIC was frequently observed in prediabetic and T2D individuals, and was associated with the disruption of certain glycemic markers in some cases.

CONCLUSION

The extent of iron overload, as indicated by hepatic iron load, varied among the prediabetic and T2D populations studied. Further research is needed to understand the distribution and regulation of iron in T2D pathology.

Eltrombopag restores proliferative capacity and adipose-osteogenic balance of mesenchymal stromal cells in low-risk myelodysplastic syndromes

In low-risk myelodysplastic syndromes (MDS), the proinflammatory signaling is excessive, and the proliferation and differentiation potentials of mesenchymal stromal cells (MSCs) are strongly impaired. Eltrombopag (ELT) has been demonstrated recently effective and relatively safe in low-risk MDS with severe thrombocytopenia. However, its impact on the MDS-MSCs has not been investigated in any detail. Here, for the first time, we investigated the changes induced by ELT in MSCs' viability, proliferation, apoptosis, senescence, multilineage differentiation properties, and stem cell support capacity in low-risk MDS patients. We demonstrated that ELT may act on improving the impaired inflammatory profile and reactivating the downregulated canonical WNT signaling pathway in low-risk MDS, and also restoring the self-renewal capacity and the balance in adipose-osteogenic differentiation of MDS-MSCs.

Metabolic dysregulation in myelodysplastic neoplasm: impact on pathogenesis and potential therapeutic targets

Despite significant advancements in the research of the pathogenesis mechanisms of Myelodysplastic Neoplasm (MDS) in recent years, there are still many gaps to fill. The advancement of metabolomics studies has led to a research booming in clarifying the impact of metabolic abnormalities during the pathogenesis of MDS. The present review primarily focuses on the dysregulated metabolic pathways, exploring the influences on the pathogenesis of MDS and their roles during the course of the disease. Furthermore, we discuss the potential of relevant metabolic pathways as therapeutic targets, along with the latest metabolic-related treatment drugs and approaches.

Iron overload in acquired sideroblastic anemias and MDS: pathophysiology and role of chelation and luspatercept

Besides transfusion therapy, ineffective erythropoiesis contributes to systemic iron overload in myelodysplastic syndromes with ring sideroblasts (MDS-RS) via erythroferrone-induced suppression of hepcidin synthesis in the liver, leading to increased intestinal iron absorption. The underlying pathophysiology of MDS-RS, characterized by disturbed heme synthesis and mitochondrial iron accumulation, is less well understood. Several lines of evidence indicate that the mitochondrial transporter ABCB7 is critically involved. ABCB7 is misspliced and underexpressed in MDS-RS, due to somatic mutations in the splicing factor SF3B1. The pathogenetic significance of ABCB7 seems related to its role in stabilizing ferrochelatase, the enzyme incorporating iron into protoporphyrin IX to make heme. Although iron-related oxidative stress is toxic, many patients with MDS do not live long enough to develop clinical complications of iron overload. Furthermore, it is difficult to determine the extent to which iron overload contributes to morbidity and mortality in older patients with MDS, because iron-related complications overlap with age-related medical problems. Nevertheless, high-quality registry studies showed that transfusion dependency is associated with the presence of toxic iron species and inferior survival and confirmed a significant survival benefit of iron chelation therapy. The most widely used iron chelator in patients with MDS is deferasirox, owing to its effectiveness and convenient oral administration. Luspatercept, which can reduce SMAD2/SMAD3-dependent signaling implicated in suppression of erythropoiesis, may obviate the need for red blood cell transfusion in MDS-RS for more than a year, thereby diminishing further iron loading. However, luspatercept cannot be expected to substantially reduce the existing iron overload.

Diagnosis and management of hereditary hemochromatosis: lifestyle modification, phlebotomy, and blood donation

The term hemochromatosis refers to a group of genetic disorders characterized by hepcidin insufficiency in the context of normal erythropoiesis, iron hyperabsorption, and expansion of the plasma iron pool with increased transferrin saturation, the diagnostic hallmark of the disease. This results in the formation of toxic non-transferrin-bound iron, which ultimately accumulates in multiple organs, including the liver, heart, endocrine glands, and joints. The most common form is HFE-hemochromatosis (HFE-H) due to p.Cys282Tyr (C282Y) homozygosity, present in nearly 1 in 200 people of Northern European descent but characterized by low penetrance, particularly in females. Genetic and lifestyle cofactors (especially alcohol and dysmetabolic features) significantly modulate clinical expression so that HFE-H can be considered a multifactorial disease. Nowadays, HFE-H is mostly diagnosed before organ damage and is easily treated by phlebotomy, with an excellent prognosis. After iron depletion, maintenance phlebotomy can be usefully transformed into a blood donation program. Lifestyle changes are important for management. Non-HFE-H, much rarer but highly penetrant, may lead to early and severe heart, liver, and endocrine complications. Managing severe hemochromatosis requires a comprehensive approach optimally provided by consultation with specialized centers. In clinical practice, a proper diagnostic approach is paramount for patients referred for hyperferritinemia, a frequent finding that reflects hemochromatosis only in a minority of cases.

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.

Assessing the performance, egg quality, serum analysis, heavy metals and essential trace metals accumulation in laying hen eggs and tissues fed black soldier fly (Hermetia illucens) larvae meal

Black soldier fly (BSF) larvae convert wastes into protein, playing a vital role in addressing the challenge of sustainable poultry production. These larvae accumulate toxic substances, posing a risk to feed and food safety. This study investigates the effects of substituting soybean meal with different levels of BSF larvae meal on laying performance, egg quality, serum analysis, and the deposition of various metals in eggs, meat, and excreta. A total of 1,008 Lohmann hens (age 48 wk) were randomly assigned to 4 treatments. The treatments consisted of corn-soybean meal (CK) diet replaced with 7% (BSF7), 14% (BSF14), and 21% (BSF21) BSF larvae meal. Each treatment consisted of 6 replicates with 42 hens each and the trial lasted for 8 wk. Dietary BSF larvae meal treatments increased (linear, P < 0.05) the laying rate (1.52 to 1.95%) and decreased (linear, P < 0.01) the feed intake (3.64-3.86 g) during the entire experiment. During 48 to 52 wk, egg weight was decreased (P < 0.001) 0.93 g for the BSF21 group compared to CK group, however, during 52-56 wk, no differences in egg weight were observed among treatments. The addition of BSF larvae meal enhanced the eggshell strength (linear, P < 0.05), with no effect on the albumen height and yolk weight (P > 0.05). Low transfer of arsenic, lead, and cadmium concentration was observed in the egg yolk and egg white across different treatments (P > 0.05). Conversely, the concentrations of these metals and iron showed an increase, while Zinc exhibited a decrease in excreta as the dietary intake of BSF larvae meal increased. The chromium and iron increased linearly (P < 0.001) in the egg white with the inclusion of BSF larvae meal. Egg white iron and chromium showed a strong positive correlation with the dietary zinc and copper. Taken together, BSF larvae can replace soybean meal completely in laying diet, however, careful attention requires to elevated metal levels in diet and excreta.

Could Hepcidin Be a New Biomarker in Patients with Idiopathic Pulmonary Fibrosis (IPF)?

Objectives: Hepcidin is a biomarker produced by hepatocytes in chronic disease anemia and is known to increase during chronic inflammation. This study compares the hepcidin levels in idiopathic pulmonary fibrosis (IPF) patients and controls, evaluating its relationship with anemia and systemic inflammation in IPF patients. Methods: This study included 82 IPF patients and 31 controls. Hepcidin levels were compared between the two groups. In the IPF group, the hepcidin and anemia parameters were compared between anemic and non-anemic patients. The significance between the hepcidin and systemic inflammation parameters such as Erythrocyte Sedimentation Rate, CRP (C-reactive protein) levels, ferritin levels, and the Systemic Immune-Inflammation Index (SII) was investigated. Erythrocyte Sedimentation Rate, C-reactive protein (CRP) levels, and ferritin levels were measured using automated analyzers. Hepcidin and erythropoietin (EPO) levels were determined using ELISA kits. Results: A significant difference in hepcidin levels was found between the IPF and control groups (37.13 ± 14.92 vs. 25.77 ± 11.25, p < 0.001). No significant difference in hepcidin levels was found between anemic and non-anemic IPF patients (38.25 ± 16.2 vs. 36.7 ± 14.6, p = 0.719). No significant correlation was found between hepcidin levels and anemia parameters (serum iron, ferritin, vitamin B12, serum transferrin, transferrin saturation, total iron-binding capacity, hemoglobin, folate, and erythropoietin) in IPF patients. Despite significant differences in the systemic inflammation parameters (ferritin and CRP) between patients and controls, no significant correlation was found between their hepcidin and systemic inflammation parameters. Conclusions: Our study demonstrates that the hepcidin levels in IPF patients are elevated independently of anemia and systemic inflammation. We propose that hepcidin could be a potential biomarker to be investigated in IPF patients.

Effect of cerium oxide on iron metabolism in mice

The use of metal nanoparticles such as cerium oxide nanoparticles (nanoceria) in living organisms is attracting increasing attention. We administered nanoceria to chronic kidney disease model rats, including a 5/6 nephrectomy model and adenine administration model rats, and reported high phosphorus adsorption capacity and renal function improvement effects of nanoceria. However, the iron ion concentration in the serum fluctuated significantly after administration. Therefore, we investigated changes in proteins related to iron metabolism following administration of nanoceria to normal mice without chronic kidney disease over different periods of time. Nanoceria were administered to 10-week-old C57BL/6 mice for 4 or 12 weeks. Another group was administrated lanthanum carbonate, which is currently used as a phosphorus adsorbent. The amount of iron in the serum and the concentration of transferrin in the liver were significantly increased following nanoceria administration, and the amount of iron in the liver was significantly decreased. There were no changes in serum hepcidin, ferroportin, cholesterol, or low-density lipoprotein levels. These results indicate that nanoceria administration can affect iron metabolism in mice. Although the detailed mechanism remains unknown, caution is warranted when considering biological utilization in the future.

Current iron therapy in the light of regulation, intestinal microbiome, and toxicity: are we prescribing too much iron?

Iron deficiency is a widespread global health concern with varying prevalence rates across different regions. In developing countries, scarcity of food and chronic infections contribute to iron deficiency, while in industrialized nations, reduced food intake and dietary preferences affect iron status. Other causes that can lead to iron deficiency are conditions and diseases that result in reduced intestinal iron absorption and blood loss. In addition, iron absorption and its bioavailability are influenced by the composition of the diet. Individuals with increased iron needs, including infants, adolescents, and athletes, are particularly vulnerable to deficiency. Severe iron deficiency can lead to anemia with performance intolerance or shortness of breath. In addition, even without anemia, iron deficiency leads to mental and physical fatigue, which points to the fundamental biological importance of iron, especially in mitochondrial function and the respiratory chain. Standard oral iron supplementation often results in gastrointestinal side effects and poor compliance. Low-dose iron therapy seems to be a valid and reasonable therapeutic option due to reduced hepatic hepcidin formation, facilitating efficient iron resorption, replenishment of iron storage, and causing significantly fewer side effects. Elevated iron levels influence gut microbiota composition, favoring pathogenic bacteria and potentially disrupting metabolic and immune functions. Protective bacteria, such as bifidobacteria and lactobacilli, are particularly susceptible to increased iron levels. Dysbiosis resulting from iron supplementation may contribute to gastrointestinal disorders, inflammatory bowel disease, and metabolic disturbances. Furthermore, gut microbiota alterations have been linked to mental health issues. Future iron therapy should consider low-dose supplementation to mitigate adverse effects and the impact on the gut microbiome. A comprehensive understanding of the interplay between iron intake, gut microbiota, and human health is crucial for optimizing therapeutic approaches and minimizing potential risks associated with iron supplementation.

Exploring the impact of estrogen-related receptor gamma on metabolism and disease

Estrogen-related receptor gamma (ERRγ) is a member of the ERR orphan nuclear receptor family which possesses three subtypes, α, β, and γ. ERRγ is reportedly predominantly expressed in metabolically active tissues and cells, which promotes positive and negative effects in different tissues. ERRγ overexpression in the liver, pancreas, and thyroid cells is related to liver cancer, oxidative stress, reactive oxygen species (ROS) regulation, and carcinoma. Reduced ERRγ expression in the brain, immune cells, tumor cells, and energy metabolism causes neurological dysfunction, gastric cancer, and obesity. ERRγ is a constitutive receptor; however, its transcriptional activity also depends on co-regulators, agonists, and antagonists, which, when after forming a complex, can play a role in targeting and treating diseases. Moreover, ERRγ has proven crucial in regulating cellular and metabolic activity. However, many functions mediated via ERRγ remain unknown and require further exploration. Hence, considering the importance of ERRγ, this review focuses on the critical findings and interactions between ERRγ and co-regulators, agonists, and antagonists alongside its relationship with downstream and upstream signaling pathways and diseases. This review highlights new findings and provides a path to understanding the current ideas and future studies on ERRγ-mediated cellular activity.

Metals in nanomotion: probing the role of extracellular vesicles in intercellular metal transfer

Metals in living organisms and environments are essential for key biological functions such as enzymatic activity, and DNA and RNA synthesis. This means that disruption of metal ion homeostasis and exchange between cells can lead to diseases. EVs are believed to play an essential role in transporting metals between cells, but the mechanism of metal packaging and exchange remains to be elucidated. Here, we established the elemental composition of EVs at the nanoscale and single-vesicle level and showed that the metal content depends on the cell type and culture microenvironment. We also demonstrated that EVs participate in the exchange of metal elements between cells. Specifically, we used two classes of EVs derived from papaya fermented fluid (PaEVs), and decidual mesenchymal stem/stromal cells (DEVs). To show that EVs transfer metal elements to cells, we treated human osteoblast-like cells (MG63) and bone marrow mesenchymal stem cells (BMMSCs) with both classes of EVs. We found that both classes of EVs contained various metal elements, such as Ca, P, Mg, Fe, Na, Zn, and K, originating from their parent cells, but their relative concentrations did not mirror the ones found in the parent cells. Single-particle analysis of P, Ca, and Fe in DEVs and PaEVs revealed varying element masses. Assuming spherical geometry, the mean mass of P was converted to a mean size of 62 nm in DEVs and 24 nm in PaEVs, while the mean sizes of Ca and Fe in DEVs were smaller, converting to 20 nm and 30 nm respectively. When EVs interacted with BMMSCs and MG63, DEVs increased Ca, P, and Fe concentrations in BMMSCs and increased Fe concentration in MG63, while PaEVs increased Ca concentrations in BMMSCs and had no effect on MG63. The EV cargo, including proteins, nucleic acids, and lipids, differs from their origin in composition, and this variation extends to the element composition of EVs in our study. This fundamental understanding of EV-mediated metal exchange between cells could offer a new way of assessing EV functionality by measuring their elemental composition. Additionally, it will contribute novel insights into the mechanisms underlying EV production and their biological activity.

Ironing Out the Mechanism of gp130 Signaling

gp130 functions as a shared signal-transducing subunit not only for interleukin (IL)-6 but also for eight other human cytokine receptor complexes. The IL-6 signaling pathway mediated through gp130 encompasses classical, trans, or cluster signaling, intricately regulated by a diverse array of modulators affecting IL-6, its receptor, and gp130. Currently, only a limited number of small molecule antagonists and agonists for gp130 are known. This review aims to comprehensively examine the current knowledge of these modulators and provide insights into their pharmacological properties, particularly in the context of cancer and other diseases. Notably, the prominent gp130 modulators SC144, bazedoxifene, and raloxifene are discussed in detail, with a specific focus on the discovery of SC144's iron-chelating properties. This adds a new dimension to the understanding of its pharmacological effects and therapeutic potential in conditions where iron homeostasis is significant. Our bioinformatic analysis of gp130 and genes related to iron homeostasis reveals insightful correlations, implicating the role of iron in the gp130 signaling pathway. Overall, this review contributes to the evolving understanding of gp130 modulation and its potential therapeutic applications in various disease contexts. SIGNIFICANCE STATEMENT: This perspective provides a timely and comprehensive analysis of advancements in gp130 signaling research, emphasizing the therapeutic implications of the currently available modulators. Bioinformatic analysis demonstrates potential interplay between gp130 and genes that regulate iron homeostasis, suggesting new therapeutic avenues. By combining original research findings with a broader discussion of gp130's therapeutic potential, this perspective significantly contributes to the field.

Resistance physical exercise modulates metabolic adipokines, decreases body weight, and improves glomerular filtration in patients with chronic kidney disease in hemodialysis

Chronic kidney disease (CKD) is a condition characterized by abnormalities in kidney structure and function that persist for more than 3 months. It is estimated that more than 800 million people in the world have a diagnosis of CKD. To remove the harmful metabolic substances from the body, people with CKD need to perform hemodialysis. Due to their beneficial effects against a wide range of clinical conditions, physical exercise is considered a non-pharmacological therapy. This study aimed to evaluate the beneficial effects of resistance exercise during hemodialysis on metabolic adipokines, myokines, body weight, and glomerular filtration rate in patients living with CKD. Briefly, the blood samples were collected in two moments: immediately before the start of the resistance exercise protocol and 1 week after the end of the protocol. Resistance exercise protocol was performed thrice a week for 12 weeks and applied during hemodialysis sessions. Here, resistance exercise increases the circulating irisin (14.56%; p = 0.0112), handgrip strength (5.70%; p = 0.0036), glomerular filtration rate (25.9%; p = 0.022) and significantly decreases adiponectin (- 55.7%; p = 0.0044), body weight (- 3.7%; p = 0.0001), glucose (- 22%; p = 0.009), and albumin levels (- 9.55%; p = 0.0001). Conversely, leptin levels (- 10.9%; p = 0.38), iron (3.05%; p = 0.705), ferritin (3.24%; p = 0.880), hemoglobin (- 0.52%; p = 0.75), total cholesterol (7.9%; p = 0.19), LDL (- 9.99%; p = 0.15) and HDL (- 4.8%; p = 0.45), did not change after resistance exercise. Interestingly, 1,25 hydroxyvitamin D levels were significantly increased (14.5%; p = 0.01) following resistance exercise. Considering the effect of sex (males vs. females), we found that irisin levels increased in females but not in males after the resistance exercise protocol. Furthermore, handgrip strength and body weight were different, indicating that males had the highest strength and weight. We demonstrated that both males and females had lower albumin levels after the resistance exercise protocol. In conclusion, we suggest that resistance exercise has beneficial effects in the CKD population by modulating adipokines and metabolic myokines and therefore can be used as a non-pharmacological adjunctive therapy in CKD patients undergoing HD.

Targeting Ferroptosis as an Advance Strategy in Cancer Therapy

Significance: This study innovates by systematically integrating the molecular mechanisms of iron death and its application in cancer therapy. By deeply analyzing the interaction between iron death and the tumor microenvironment, the study provides a new theoretical basis for cancer treatment and directions for developing more effective treatment strategies. In addition, the study points to critical issues and barriers that need to be addressed in future research, providing valuable insights into the use of iron death in clinical translation. Recent Advances: These findings are expected to drive further advances in cancer treatment, bringing patients more treatment options and hope. Through this paper, we see the great potential of iron death in cancer treatment and look forward to more research results being translated into clinical applications in the future to contribute to the fight against cancer. Critical Issues: In today's society, cancer is still one of the major diseases threatening human health. Despite advances in existing treatments, cancer recurrence and drug resistance remain a severe problem. These problems increase the difficulty of treatment and bring a substantial physical and mental burden to patients. Therefore, finding new treatment strategies to overcome these challenges has become significant. Future Directions: The study delved into the molecular basis of iron death in tumor biology. It proposed a conceptual framework to account for the interaction of iron death with the tumor immune microenvironment, guide treatment selection, predict efficacy, explore combination therapies, and identify new therapeutic targets to overcome cancer resistance to standard treatments, peeving a path for future research and clinical translation of ferroptosis as a potential strategy in cancer therapy. Antioxid. Redox Signal. 41, 616-636. [Figure: see text].

Association of urinary glyphosate levels with iron homeostasis among a representative sample of US adults: NHANES 2013-2018

PURPOSE

Glyphosate and glyphosate-based herbicides (GBH), widely used globally, were initially considered harmless to humans. Experimental studies have suggested that these substances can disrupt iron homeostasis by interfering with iron uptake or triggering inflammatory responses. However, their potential impact on human iron homeostasis remains underexplored.

APPROACH AND RESULTS

We analyzed data from 5812 participants aged three and older from the 2013 to 2018 NHANES. We investigated the relationships between urinary glyphosate levels, oral iron intake, and markers of iron homeostasis, including serum iron, unsaturated iron-binding capacity (UIBC), total iron-binding capacity (TIBC), transferrin saturation, ferritin, and transferrin receptor. Higher urinary glyphosate levels were positively associated with oral iron intake (β = 1.310, S.E. = 0.382, P = 0.001). A one-unit increase in the natural logarithm (ln)-glyphosate was associated with lower serum iron (β = - 4.236, 95 % CI = - 6.432 to - 2.039, P < 0.001) and ferritin (β = - 9.994, 95 % CI = - 17.342 to - 2.647, P = 0.009), and higher UIBC (β = 5.431, 95 % CI = 1.061-9.800, P = 0.018) and transferrin receptor levels (β = 0.139, 95 % CI = 0.015-0.263, P = 0.029). Increasing glyphosate exposure was associated with significant decreases in serum iron and ferritin across exposure quintiles (trend P-values = 0.003 and 0.018, respectively).

CONCLUSIONS

Higher glyphosate exposure is associated with reduced iron availability, suggesting potential disruptions in iron absorption. These findings underscore the need for further research into the health implications of glyphosate exposure on iron homeostasis.

Sex similarities and divergences in systemic and muscle iron metabolism adaptations to extreme physical inactivity in rats

BACKGROUND

Previous data in humans suggest that extreme physical inactivity (EPI) affects iron metabolism differently between sexes. Our objective was to deepen the underlying mechanisms by studying rats of both sexes exposed to hindlimb unloading (HU), the reference experimental model mimicking EPI.

METHODS

Eight-week-old male and female Wistar rats were assigned to control (CTL) or hindlimb unloading (HU) conditions (n = 12/group). After 7 days of HU, serum, liver, spleen, and soleus muscle were removed. Iron parameters were measured in serum samples, and ICP-MS was used to quantify iron in tissues. Iron metabolism genes and proteins were analysed by RT-qPCR and Western blot.

RESULTS

Compared with control males, control females exhibited higher iron concentrations in serum (+43.3%, p < 0.001), liver (LIC; +198%, P < 0.001), spleen (SIC; +76.1%, P < 0.001), and transferrin saturation (TS) in serum (+53.3%, P < 0.001), contrasting with previous observations in humans. HU rat males, but not females, exhibited an increase of LIC (+54% P < 0.001) and SIC (+30.1%, P = 0.023), along with a rise of H-ferritin protein levels (+60.9% and +134%, respectively, in liver and spleen; P < 0.05) and a decrease of TFRC protein levels (-36%; -50%, respectively, P < 0.05). HU males also exhibited an increase of splenic HO-1 and NRF2 mRNA levels, (p < 0.001), as well as HU females (P < 0.001). Concomitantly to muscle atrophy observed in HU animals, the iron concentration increased in soleus in females (+26.7, P = 0.004) while only a trend is observed in males (+17.5%, P = 0.088). In addition, the H-ferritin and myoglobin protein levels in soleus were increased in males (+748%, P < 0.001, +22%, P = 0.011, respectively) and in females (+369%, P < 0.001, +21.9%, P = 0.007, respectively), whereas TFRC and ferroportin (FPN) protein levels were reduced in males (-68.9%, P < 0.001, -76.8%, P < 0.001, respectively) and females (-75.9%, P < 0.001, -62.9%, P < 0.001, respectively). Interestingly, in both sexes, heme exporter FLVCR1 mRNA increased in soleus, while protein levels decreased (-39.9% for males P = 0.010 and -49.1% for females P < 0.001).

CONCLUSIONS

Taken together, these data support that, in rats (1) extreme physical inactivity differently impacts the distribution of iron in both sexes, (2) splenic erythrophagocytosis could play a role in this iron misdistribution. The higher iron concentrations in atrophied soleus from both sexes are associated with a decoupling between the increase in iron storage proteins (i.e., ferritin and myoglobin) and the decrease in levels of iron export proteins (i.e., FPN and FLVCR1), thus supporting an iron sequestration in skeletal muscle under extreme physical inactivity.

The Role of Ferroptosis in Amyotrophic Lateral Sclerosis Treatment

Amyotrophic lateral sclerosis (ALS) is a rare neurodegenerative disease with a challenging treatment landscape, due to its complex pathogenesis and limited availability of clinical drugs. Ferroptosis, an iron-dependent form of programmed cell death (PCD), stands distinct from apoptosis, necrosis, autophagy, and other cell death mechanisms. Recent studies have increasingly highlighted the role of iron deposition, reactive oxygen species (ROS) accumulation, oxidative stress, as well as systemic Xc- and glutamate accumulation in the antioxidant system in the pathogenesis of amyotrophic lateral sclerosis. Therefore, targeting ferroptosis emerges as a promising strategy for amyotrophic lateral sclerosis treatment. This review introduces the regulatory mechanism of ferroptosis, the relationship between amyotrophic lateral sclerosis and ferroptosis, and the drugs used in the clinic, then discusses the current status of amyotrophic lateral sclerosis treatment, hoping to provide new directions and targets for its treatment.

The role of corticosteroids in the current treatment paradigm for myelofibrosis

INTRODUCTION

Myelofibrosis (MF) is a clonal hematological disorder characterized by bone marrow fibrosis, splenomegaly, and inflammatory cytokine dysregulation. While the role of steroids in MF is not fully defined, their anti-inflammatory properties may offer therapeutic benefits, particularly in managing anemia and other cytopenias. Steroids exert their effects by suppressing pro-inflammatory cytokines such as IL1, IL6, and TNF, and by enhancing anti-inflammatory cytokines like IL4 and IL10. Elevated levels of IL6 and other cytokines in MF are associated with anemia and poor prognosis, suggesting that steroid therapy could mitigate these effects.

AREAS COVERED

In this manuscript, we review clinical studies which evaluated the safety and efficacy of steroids in MF patients. Moreover, we examine clinical data of the combination of steroids with immunomodulatory agents and JAK inhibitors. Our literature search consisted of an extensive review of PubMed and clinicaltrials.gov.

EXPERT OPINION

The role of steroids in the management of MF remains poorly defined, though emerging evidence suggests a potential therapeutic benefit, particularly in managing anemia and other cytopenias. The combination with IMIDs has also yielded positive outcomes as demonstrated in several studies. Steroids may also play a crucial role in managing cytopenias in MF patients receiving JAKi.

Putamen iron quantification in diseases with neurodegeneration: a meta-analysis of the quantitative susceptibility mapping technique

Quantitative susceptibility mapping (QSM) is an MRI technique that accurately measures iron concentration in brain tissues. This meta-analysis synthesized evidence from 30 studies that used QSM to quantify the iron levels in the putamen. The PRISMA statement was adhered to when conducting the systematic reviews and meta-analyses. We conducted a meta-analysis using a random-effects model, as well as subgroup analyses (disease type, geographic region, field strength, coil, disease type, age, and sex) and sensitivity analysis. A total of 1247 patients and 1035 controls were included in the study. Pooled results showed a standardized mean difference (SMD) of 0.41 (95% CI 0.19 to 0.64), with the strongest effect seen in Alzheimer's disease (AD) at 1.01 (95% CI 0.50 to 1.52). Relapsing-remitting multiple sclerosis (RRMS) also showed increased putaminal iron at 0.37 (95% CI 0.177 to 0.58). No significant differences were observed in Parkinson's disease (PD). No significant differences were found between subgroups based on geographic region, field strength, coil, disease type, age, and sex. The studies revealed significant heterogeneity, with field strength as the primary source, while other factors, such as disease type, location, age, sex, and coil type, may have contributed. The sensitivity analysis showed that these factors did not have a significant influence on the overall results. In summary, this meta-analysis supports abnormalities in putaminal iron content across different diseases with neurodegeneration, especially AD and RRMS, as measured by QSM. This highlights the potential of QSM as an imaging biomarker to better understand disease mechanisms involving disturbances in brain iron homeostasis.

Nutritional Consequences of Celiac Disease and Gluten-Free Diet

Celiac disease is an immune-mediated condition triggered by gluten ingestion in genetically predisposed individuals. The global prevalence of celiac disease is significant, affecting approximately 1.4% of women and 0.7% of men, with incidence rates of 17.4 and 7.8 per 100,000 person-years, respectively. The clinical presentation of celiac disease may range from overt diarrhea and malabsorption to more subtle features such as nutritional deficiencies and extraintestinal manifestations. It is the most common cause of global malabsorption in Western countries. A life-long gluten-free diet is the only available treatment for celiac disease. Moreover, a gluten-free diet is often adopted by individuals without celiac disease, either to address non-celiac gluten sensitivity or for other reasons. This review aims to explore the current understandings of the nutritional consequences of untreated celiac disease and the impact of the gluten-free diet itself. Physicians and dietitians specializing in celiac disease should focus on providing a well-rounded nutritional scheme to address deficiencies caused by the disease and prevent the instauration of new nutritional imbalances.

Ferroptosis: Regulatory mechanisms and potential targets for bone metabolism: A review

Bone homeostasis is a homeostasis process constructed by osteoblast bone formation and osteoclast bone resorption. Bone homeostasis imbalance and dysfunction are the basis for the development of various orthopedic diseases such as osteoporosis, osteoarthritis, and steroid-induced avascular necrosis of femoral head. Previous studies have demonstrated that ferroptosis can induce lipid peroxidation through the generation of reactive oxygen species, activate a number of signaling pathways, and participate in the regulation of osteoblast bone formation and osteoclast bone resorption, resulting in bone homeostasis imbalance, which is an important factor in the pathogenesis of many orthopedic diseases, but the mechanism of ferroptosis is still unknown. In recent years, it has been found that, in addition to iron metabolism and intracellular antioxidant system imbalance, organelle dysfunction is also a key factor affecting ferroptosis. This paper takes this as the starting point, reviews the latest literature reports at home and abroad, elaborates the pathogenesis and regulatory pathways of ferroptosis and the relationship between ferroptosis and various organelles, and summarizes the mechanism by which ferroptosis mediates bone homeostasis imbalance, with the aim of providing new directions for the research related to ferroptosis and new ideas for the prevention and treatment of bone and joint diseases.

Targeting PKCα alleviates iron overload in diabetes and hemochromatosis through the inhibition of ferroportin

ABSTRACT

Ferroportin (Fpn) is the only iron exporter, playing a crucial role in systemic iron homeostasis. Fpn is negatively regulated by its ligand hepcidin, but other potential regulators in physiological and disease conditions remain poorly understood. Diabetes is a metabolic disorder that develops body iron loading with unknown mechanisms. By using diabetic mouse models and human duodenal specimens, we demonstrated that intestinal Fpn expression was increased in diabetes in a hepcidin-independent manner. Protein kinase C (PKC) is hyperactivated in diabetes. We showed that PKCα was required to sustain baseline Fpn expression and diabetes-induced Fpn upregulation in the enterocytes and macrophages. Knockout of PKCα abolished diabetes-associated iron overload. Mechanistically, activation of PKCα increased the exocytotic trafficking of Fpn and decreased the endocytic trafficking of Fpn in the resting state. Hyperactive PKCα also suppressed hepcidin-induced ubiquitination, internalization, and degradation of Fpn. We further observed that iron loading in the enterocytes and macrophages activated PKCα, acting as a novel mechanism to enhance Fpn-dependent iron efflux. Finally, we demonstrated that the loss-of-function of PKCα and pharmacological inhibition of PKC significantly alleviated hereditary hemochromatosis-associated iron overload. Our study has highlighted, to our knowledge, for the first time, that PKCα is an important positive regulator of Fpn and a new target in the control of iron homeostasis.

SUGP2 p.(Arg639Gln) variant is involved in the pathogenesis of hemochromatosis via the CIRBP/BMPER signaling pathway

Pathogenic variants in HFE and non-HFE genes have been identified in hemochromatosis in different patient populations, but there are still a certain number of patients with unexplained primary iron overload. We recently identified in Chinese patients a recurrent p.(Arg639Gln) variant in SURP and G-patch domain containing 2 (SUGP2), a potential mRNA splicing-related factor. However, the target gene of SUGP2 and affected iron-regulating pathway remains unknown. We aimed to investigate the pathogenicity and underlying mechanism of this variant in hemochromatosis. RNA-seq analysis revealed that SUGP2 knockdown caused abnormal alternative splicing of CIRBP pre-mRNA, resulting in an increased normal splicing form of CIRBP V1, which in turn increased the expression of BMPER by enhancing its mRNA stability and translation. Furthermore, RNA-protein pull-down and RNA immunoprecipitation assays revealed that SUGP2 inhibited splicing of CIRBP pre-mRNA by a splice site variant at CIRBP c.492 and was more susceptible to CIRBP c.492 C/C genotype. Cells transfected with SUGP2 p.(Arg639Gln) vector showed up-regulation of CIRBP V1 and BMPER expression and down-regulation of pSMAD1/5 and HAMP expression. CRISPR-Cas9 mediated SUGP2 p.(Arg622Gln) knock-in mice showed increased iron accumulation in the liver, higher total serum iron, and decreased serum hepcidin level. A total of 10 of 54 patients with hemochromatosis (18.5%) harbored the SUGP2 p.(Arg639Gln) variant and carried CIRBP c.492 C/C genotype, and had increased BMPER expression in the liver. Altogether, the SUGP2 p.(Arg639Gln) variant down-regulates hepcidin expression through the SUGP2/CIRBP/BMPER axis, which may represent a novel pathogenic factor for hemochromatosis.

Inflammation related to inhalation of nano and micron sized iron oxides: a systematic review

Inhalation exposure to iron oxide occurs in many workplaces and respirable aerosols occur during thermal processes (e.g. welding, casting) or during abrasion of iron and steel products (e.g. cutting, grinding, machining, polishing, sanding) or during handling of iron oxide pigments. There is limited evidence of adverse effects in humans specifically linked to inhalation of iron oxides. This contrasts to oxides of other metals used to alloy or for coating of steel and iron of which several have been classified as being hazardous by international and national agencies. Such metal oxides are often present in the air at workplaces. In general, iron oxides might therefore be regarded as low-toxicity, low-solubility (LTLS) particles, and are often considered to be nontoxic even if very high and prolonged inhalation exposures might result in diseases. In animal studies, such exposures lead to cancer, fibrosis and other diseases. Our hypothesis was that pulmonary-workplace exposure during manufacture and handling of SPION preparations might be harmful. We therefore conducted a systematic review of the relevant literature to understand how iron oxides deposited in the lung are related to acute and subchronic pulmonary inflammation. We included one human and several in vivo animal studies published up to February 2023. We found 25 relevant studies that were useful for deriving occupational exposure limits (OEL) for iron oxides based on an inflammatory reaction. Our review of the scientific literature indicates that lowering of health-based occupational exposure limits might be considered.

Pharmacokinetics, pharmacodynamics, and tolerability of an aqueous formulation of rusfertide (PTG-300), a hepcidin mimetic, in healthy volunteers: A double-blind first-in-human study

OBJECTIVES

Rusfertide is a potent peptide mimetic of hepcidin being investigated for the treatment of polycythemia vera. This randomized, placebo-controlled, double-blind study evaluated the safety, pharmacokinetics, and pharmacodynamics of single and repeated subcutaneous doses of an aqueous formulation of rusfertide in healthy adult males.

METHODS

Subjects received single doses of 1, 3, 10, 20, 40, or 80 mg rusfertide or placebo. A separate cohort of subjects received two doses of 40 mg rusfertide or placebo 1 week apart. Blood samples for pharmacokinetics and pharmacodynamics were collected, and adverse events, clinical laboratory tests, 12-lead electrocardiograms, and vital signs were monitored.

RESULTS

Rusfertide was well tolerated. There were no serious or severe treatment-emergent adverse events, and no patterns of clinically important adverse events, or laboratory, vital sign, or electrocardiogram abnormalities. Mean maximum rusfertide plasma concentration (Cmax) and area under the concentration-time curve increased with dose, but less than dose proportionally. Median time to Cmax was 2-4.5 h for 40 and 80 mg rusfertide and 8-24 h for lower doses. Apparent clearance and half-life increased with dose. Single doses of rusfertide 1-80 mg were associated with dose-dependent decreases in serum iron and transferrin-iron saturation.

CONCLUSIONS

Rusfertide was well tolerated and showed dose-dependent pharmacokinetics and pharmacodynamics.

Iron absorption in adults with sickle cell anemia: a stable-isotope approach

PURPOSE

Iron absorption in sickle cell anemia (SCA) remains unclear and studies in adults with SCA are scarce. The aim of this study was to evaluate the iron absorption SCA adults and its association with iron status and hepcidin concentration.

METHODS

SCA patients (n = 13; SCAtotal) and control participants (n = 10) ingested an oral stable iron isotope (57Fe). Iron absorption was measured by inductively coupled plasma mass spectrometry (ICP-MS) 14 days after isotope administration. Patients with ≥ 1000 ng/mL serum ferritin were considered to present iron overload (IO) (SCAio+; n = 3) and others classified without IO (SCAio-; n = 10).

RESULTS

Iron absorption in the control group ranged from 0.3 to 26.5% (median = 0.9%), while it varied from 0.3 to 5.4% in SCAio+ (median = 0.5%) and from 0.3 to 64.2% in the SCAio- (median = 6.9%). Hepcidin median values were 14.1 ng/mL (3.0-31.9 ng/mL) in SCAio-, 6.2 ng/mL (3.3-7.8 ng/mL) in SCAio + and 6.2 ng/mL (0.6-9.3 ng/mL) in control. Iron absorption was associated with ferritin level (r = - 0.641; p = 0.018) and liver iron concentration (LIC; r = - 0.786; p = 0.036) in the SCAtotal group.

CONCLUSION

Our data suggest that SCAio- individuals may be at risk of developing primary IO. Simultaneously, secondary IO may induce physiological adaptation, resulting in reduced iron absorption. Further studies evaluating intestinal iron absorption using larger sample sizes should be conducted to help establish a safe nutrition approach to be adopted and to ensure the security of food-fortifying public policies for these patients.

TRIAL REGISTRATION

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

Tannic Acid Suppresses Ferroptosis Induced by Iron Salophene Complex in Kidney Cells and Prevents Iron Overload-Induced Liver and Kidney Dysfunction in Rats

Iron toxicity intricately links with ferroptosis, a unique form of cell death, and is significantly influenced by lipid peroxidation. Despite its critical role in various diseases and drug development, the association between iron toxicity and ferroptosis remains relatively unexplored. Accidental iron ingestion has emerged as a growing concern, resulting in a spectrum of symptoms ranging from gastrointestinal discomfort to severe outcomes, including mortality. This research introduces tannic acid (TA), which contains numerous phenol groups, as a powerful antiferroptotic agent. In male Wistar rats, even a modest dose of TA (7.5 mg/kg) significantly curtailed thiobarbituric acid reactive substances (TBARS), a well-established indicator of lipid peroxidation, and mitigated iron accumulation induced by ferrous sulfate (FeSO4) in the liver and kidney. The evidence supporting TA's protective function against iron-triggered liver and kidney dysfunction was substantiated by assessing specifically the levels of blood urea nitrogen (BUN) and alanine aminotransferase (ALT). In cell models using ferroptosis inducers such as iron-salophene (FeSP) and RAS-selective lethal 3 (RSL3), tannic acid (TA) exhibited superior protective capabilities compared to the traditional iron chelator, deferoxamine (DFO). Nrf2 and HO-1, regulators of antioxidant defense genes, are implicated in controlling ferroptosis. The expression of Nrf2 and HO-1 increased with TA treatment in the presence of FeSP, indicating their role in reducing lipid ROS levels. Additionally, TA significantly reduced the heightened levels of COX2, a marker associated with ferroptosis. In summary, the remarkable antiferroptosis activity of TA is likely due to its combined iron-chelating and antioxidant properties. With its safety profile for oral consumption, TA may offer benefits in cases of accidental iron ingestion and conditions like hemochromatosis.

Iron Homeostasis-Related Parameters and Hepcidin/Ferritin Ratio: Emerging Sex-Specific Predictive Markers for Metabolic Syndrome

Metabolic syndrome (MetS) is a worldwide public health challenge. Accumulating evidence implicates elevated serum ferritin and disruptions in iron metabolism as potential elements linked to an increased risk of MetS. This study investigates the relationship between iron homeostasis-including hepcidin levels, serum iron concentration, unsaturated iron-binding capacity (UIBC), and the hepcidin/ferritin (H/F) ratio-and MetS. In this descriptive cross-sectional study, 209 participants aged 24-70 were categorized into two groups: 103 with MetS and 106 without MetS. All participants underwent medical assessment, including anthropometric measures, indices of glycemic control, lipid profiles, and iron-related parameters. Participants were further stratified by the Homeostasis Model Assessment-Insulin Resistance index into three subgroups: insulin-sensitive (IS) (<1.9), early insulin resistance (EIR) (>1.9 to <2.9), and significant insulin resistance (SIR) (>2.9). Notable increments in serum ferritin and hepcidin were observed in the SIR group relative to the IS and EIR groups, with a significant association between metabolic parameters. The UIBC and serum ferritin emerged as significant predictors of MetS, particularly in men, with an area under the curve (AUC) of 0.753 and 0.792, respectively (p ≤ 0.001). In contrast, hepcidin was notably correlated with MetS in women, with an AUC of 0.655 (p = 0.007). The H/F ratio showed superior predictive capability for MetS across both sexes (at cutoff level = 0.67). Among women, this ratio had an AUC of 0.639 (p = 0.015), and for men, it had an AUC of 0.792 (p < 0.001). Hypertension proved an independent risk factor for MetS, affirming its role in metabolic dysregulation. The findings highlight a significant interconnection between iron homeostasis parameters and MetS, with sex-specific variations underscoring the importance of personalized diagnostic criteria. The crucial role of the H/F ratio and the UIBC as emerging predictive markers for MetS indicates their potential utility in identifying at-risk individuals. Further longitudinal research is essential to establish causality and explore the interplay between these biomarkers and MetS.

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.

Metal ions overloading and cell death

Cell death maintains cell morphology and homeostasis during development by removing damaged or obsolete cells. The concentration of metal ions whithin cells is regulated by various intracellular transporters and repositories to maintain dynamic balance. External or internal stimuli might increase the concentration of metal ions, which results in ions overloading. Abnormal accumulation of large amounts of metal ions can lead to disruption of various signaling in the cell, which in turn can produce toxic effects and lead to the occurrence of different types of cell deaths. In order to further study the occurrence and development of metal ions overloading induced cell death, this paper reviewed the regulation of Ca2+, Fe3+, Cu2+ and Zn2+ metal ions, and the internal mechanism of cell death induced by overloading. Furthermore, we found that different metal ions possess a synergistic and competitive relationship in the regulation of cell death. And the enhanced level of oxidative stress was present in all the processes of cell death due to metal ions overloading, which possibly due to the combination of factors. Therefore, this review offers a theoretical foundation for the investigation of the toxic effects of metal ions, and presents innovative insights for targeted regulation and therapeutic intervention. HIGHLIGHTS: • Metal ions overloading disrupts homeostasis, which in turn affects the regulation of cell death. • Metal ions overloading can cause cell death via reactive oxygen species (ROS). • Different metal ions have synergistic and competitive relationships for regulating cell death.

Abdominal multi-organ iron content and the risk of Parkinson's disease: a Mendelian randomization study

Background

To evaluate the causal relationship between abdominal multi-organ iron content and PD risk using publicly available genome-wide association study (GWAS) data.

Methods

We conducted MR analysis to assess the effects of iron content in various abdominal organs on PD risk, followed by reverse analysis. Additionally, MVMR analysis evaluated the independent effects of organ-specific iron content on PD. We utilized genetic variation data from the UK Biobank, including liver iron content (n = 32,858), spleen iron content (n = 35,324), and pancreas iron content (n = 25,617), as well as summary-level data for Parkinson's disease from the FinnGen (n = 218,473) and two other large GWAS datasets of European populations (First dataset n = 480,018; Second dataset n = 2,829). The primary MR analysis used the inverse variance-weighted (IVW) method, confirmed by MR-Egger and weighted median methods. Sensitivity analysis was performed to address potential pleiotropy and heterogeneity. Observational cohort results were validated through replication cohort analysis, followed by meta-analysis.

Results

IVW analysis revealed a causal relationship between increased liver iron content and elevated risk of PD (OR = 1.27; 95% CI: 1.05-1.53; p = 0.015). No significant causal relationship was observed between spleen (OR = 1.00; 95% CI: 0.76-1.32; p = 0.983) and pancreatic (OR = 0.93; 95% CI: 0.72-1.20; p = 0.573) iron content and increased risk of PD. Meta-analysis of GWAS data for PD from three different sources using the random-effects IVW method showed a statistically significant causal relationship between liver iron content and the occurrence of PD (OR = 1.17, 95% CI: 1.01-1.35; p = 0.012).

Conclusion

This study presents evidence from Mendelian randomization (MR) analysis indicating a significant causal link between increased liver iron content and a higher risk of Parkinson's disease (PD). These findings suggest that interventions targeting body iron metabolism, particularly liver iron levels, may be effective in preventing PD.

High ferritin is associated with liver and bone marrow iron accumulation: Effects of 1-year deferoxamine treatment in hemodialysis-associated iron overload

BACKGROUND

Iron (Fe) supplementation is a critical component of anemia therapy for patients with chronic kidney disease (CKD). However, serum Fe, ferritin, and transferrin saturation, used to guide Fe replacement, are far from optimal, as they can be influenced by malnutrition and inflammation. Currently, there is a trend of increasing Fe supplementation to target high ferritin levels, although the long-term risk has been overlooked.

METHODS

We prospectively enrolled 28 patients with CKD on hemodialysis with high serum ferritin (> 1000 ng/ml) and tested the effects of 1-year deferoxamine treatment, accompanied by withdrawal of Fe administration, on laboratory parameters (Fe status, inflammatory and CKD-MBD markers), heart, liver, and iliac crest Fe deposition (quantitative magnetic resonance imaging [MRI]), and bone biopsy (histomorphometry and counting of the number of Fe positive cells in the bone marrow).

RESULTS

MRI parameters showed that none of the patients had heart iron overload, but they all presented iron overload in the liver and bone marrow, which was confirmed by bone histology. After therapy, ferritin levels decreased, although neither hemoglobin levels nor erythropoietin dose was changed. A significant decrease in hepcidin and FGF-23 levels was observed. Fe accumulation was improved in the liver and bone marrow, reaching normal values only in the bone marrow. No significant changes in turnover, mineralization or volume were observed.

CONCLUSIONS

Our data suggest that treatment with deferoxamine was safe and could improve Fe accumulation, as measured by MRI and histomorphometry. Whether MRI is considered a standard tool for investigating bone marrow Fe accumulation requires further investigation. Registry and the registration number of clinical trial: ReBEC (Registro Brasileiro de Ensaios Clinicos) under the identification RBR-3rnskcj available at: https://ensaiosclinicos.gov.br/pesquisador.

Functional iron deficiency anemia in patients with cancer

Anemia is frequently observed in patients with cancer owing to anticancer chemotherapy, radiation therapy, and inflammatory responses. This often leads to functional iron deficiency, characterized by adequate iron stores but impaired use of iron for red blood cell production. This condition, termed functional iron deficiency anemia (IDA), is identified by a ferritin level of 30-500 µg/dL and a transferrin saturation < 50%. Functional iron deficiency often develops with the prolonged use of erythropoiesis-stimulating agents, leading to a diminished response to anemia treatment. Although oral iron supplementation is common, intravenous iron is more effective and recommended in such cases. Recent studies have shown that ferric carboxymaltose (FCM) is effective in treating functional IDA in patients with cancer. However, because of its potential to induce asymptomatic severe phosphate deficiency, it is important to closely monitor phosphate levels in patients receiving FCM.

Social defeat stress impairs systemic iron metabolism by activating the hepcidin-ferroportin axis

Chronic psychological stress has been reported to decrease circulating iron concentrations and impair hematopoiesis. However, the underlying mechanisms remain unclear. This study aimed to investigate the effects of psychological stress on biological iron metabolism by using the social defeat stress (SDS) model, a widely used model of depression. Compared with control mice, mice subjected to SDS (SDS mice) had lower social interaction (SI) behavior. The SDS mice also showed impaired hematopoiesis, as evidenced by reduced circulating red blood cell counts, elevated reticulocyte counts, and decreased plasma iron levels. In the SDS mice, the iron contents in the bone marrow decreased, whereas those in the spleen increased, suggesting dysregulation in systemic iron metabolism. The concentrations of plasma hepcidin, an important regulator of systemic iron homeostasis, increased in the SDS mice. Meanwhile, the concentrations of ferroportin, an iron transport protein negatively regulated by hepcidin, were lower in the spleen and duodenum of the SDS mice than in those of the control mice. Treatment with dalteparin, a hepcidin inhibitor, prevented the decrease in plasma iron levels in the SDS mice. The gene expression and enzyme activity of furin, which converts the precursor hepcidin to active hepcidin, were high and positively correlated with plasma hepcidin concentration. Thus, furin activation might be responsible for the increased plasma hepcidin concentration. This study is the first to show that psychological stress disrupts systemic iron homeostasis by activating the hepcidin-ferroportin axis. Consideration of psychological stressors might be beneficial in the treatment of diseases with iron-refractory anemia.

Manganese transporter SLC30A10 and iron transporters SLC40A1 and SLC11A2 impact dietary manganese absorption

SLC30A10 deficiency is a disease of severe manganese excess attributed to loss of SLC30A10-dependent manganese excretion via the gastrointestinal tract. Patients develop dystonia, cirrhosis, and polycythemia. They are treated with chelators but also respond to oral iron, suggesting that iron can outcompete manganese for absorption in this disease. Here we explore the latter observation. Intriguingly, manganese absorption is increased in Slc30a10-deficient mice despite manganese excess. Studies of multiple mouse models indicate that increased dietary manganese absorption reflects two processes: loss of manganese export from enterocytes into the gastrointestinal tract lumen by SLC30A10, and increased absorption of dietary manganese by iron transporters SLC11A2 (DMT1) and SLC40A1 (ferroportin). Our work demonstrates that aberrant absorption contributes prominently to SLC30A10 deficiency and expands our understanding of biological interactions between iron and manganese. Based on these results, we propose a reconsideration of the role of iron transporters in manganese homeostasis is warranted.

Iron Metabolism, Calcium, Magnesium and Trace Elements: A Review

Iron (Fe) is fundamental to life on earth. In the human body, it is both essential and harmful if above threshold. A similar balance applies to other elements: calcium (Ca), magnesium (Mg), and trace elements including copper (Cu), zinc (Zn), lead (Pb), cadmium (Cd), mercury (Hg), and nickel (Ni). These elements share some proteins involved in the absorption and transport of Fe. Cu and Cd can inhibit Fe absorption, while excess of Fe may antagonize Cu metabolism and reduce ceruloplasmin (Cp). Excessive Fe can hinder Zn absorption and transferrin (Trf) can bind to both Zn and Ni. Ca is able to inhibit the divalent metal transporter 1 (DMT1) in a dose-dependent manner to reduce Fe absorption and low Mg concentrations can exacerbate Fe deficiency. Pb competitively inhibits Fe distribution and elevated Cd absorption reduces Fe uptake. Exposure to Hg is associated with higher ferritin concentrations and Ni alters intracellular Fe metabolism. Fe removal by phlebotomy in hemochromatosis patients has shown to increase the levels of Cd and Pb and alter the concentrations of trace elements in some types of anemia. Yet, the effects of chronic exposure of most trace elements remain poorly understood.

Bone morphogenetic protein 4 derived from the cerebrospinal fluid in patients with postherpetic neuralgia induces allodynia via the crosstalk between microglia and astrocyte

INTRODUCTION

During postherpetic neuralgia (PHN), the cerebral spinal fluid (CSF) possesses the capability to trigger glial activation and inflammation, yet the specific changes in its composition remain unclear. Recent findings from our research indicate elevations of central bone morphogenetic protein 4 (BMP4) during neuropathic pain (NP), serving as an independent modulator of glial cells. Herein, the aim of the present study is to test the CSF-BMP4 expressions and its role in the glial modulation in the process of PHN.

METHODS

CSF samples were collected from both PHN patients and non-painful individuals (Control) to assess BMP4 and its antagonist Noggin levels. Besides, intrathecal administration of both CSF types was conducted in normal rats to evaluate the impact on pain behavior, glial activity, and inflammation.; Additionally, both Noggin and STAT3 antagonist-Stattic were employed to treat the PHN-CSF or exogenous BMP4 challenged cultured astrocytes to explore downstream signals. Finally, microglial depletion was performed prior to the PHN-CSF intervention so as to elucidate the microglia-astrocyte crosstalk.

RESULTS

BMP4 levels were significantly higher in PHN-CSF compared to Control-CSF (P < 0.001), with a positive correlation with pain duration (P < 0.05, r = 0.502). Comparing with the Control-CSF producing moderate paw withdrawal threshold (PWT) decline and microglial activation, PHN-CSF further exacerbated allodynia and triggered both microglial and astrocytic activation (P < 0.05). Moreover, PHN-CSF rather than Control-CSF evoked microglial proliferation and pro-inflammatory transformation, reinforced iron storage, and activated astrocytes possibly through both SMAD159 and STAT3 signaling, which were all mitigated by the Noggin application (P < 0.05). Next, both Noggin and Stattic effectively attenuated BMP4-induced GFAP and IL-6 upregulation, as well as SMAD159 and STAT3 phosphorylation in the cultured astrocytes (P < 0.05). Finally, microglial depletion diminished PHN-CSF induced astrogliosis, inflammation and endogenous BMP4 expression (P < 0.05).

CONCLUSION

Our study highlights the role of CSF-BMP4 elevation in glial activation and allodynia during PHN, suggesting a potential therapeutic avenue for future exploration.

The Role of Iron Metabolism in Sepsis-associated Encephalopathy: a Potential Target

Sepsis-associated encephalopathy (SAE) is an acute cerebral dysfunction secondary to infection, and the severity can range from mild delirium to deep coma. Disorders of iron metabolism have been proven to play an important role in a variety of neurodegenerative diseases by inducing cell damage through iron accumulation in glial cells and neurons. Recent studies have found that iron accumulation is also a potential mechanism of SAE. Systemic inflammation can induce changes in the expression of transporters and receptors on cells, especially high expression of divalent metal transporter1 (DMT1) and low expression of ferroportin (Fpn) 1, which leads to iron accumulation in cells. Excessive free Fe2+ can participate in the Fenton reaction to produce reactive oxygen species (ROS) to directly damage cells or induce ferroptosis. As a result, it may be of great help to improve SAE by treatment of targeting disorders of iron metabolism. Therefore, it is important to review the current research progress on the mechanism of SAE based on iron metabolism disorders. In addition, we also briefly describe the current status of SAE and iron metabolism disorders and emphasize the therapeutic prospect of targeting iron accumulation as a treatment for SAE, especially iron chelator. Moreover, drug delivery and side effects can be improved with the development of nanotechnology. This work suggests that treating SAE based on disorders of iron metabolism will be a thriving field.

Rocaglamide regulates iron homeostasis by suppressing hepcidin expression

The anemia of inflammation (AI) is characterized by the presence of inflammation and abnormal elevation of hepcidin. Accumulating evidence has proved that Rocaglamide (RocA) was involved in inflammation regulation. Nevertheless, the role of RocA in AI, especially in iron metabolism, has not been investigated, and its underlying mechanism remains elusive. Here, we demonstrated that RocA dramatically suppressed the elevation of hepcidin and ferritin in LPS-treated mice cell line RAW264.7 and peritoneal macrophages. In vivo study showed that RocA can restrain the depletion of serum iron (SI) and transferrin (Tf) saturation caused by LPS. Further investigation showed that RocA suppressed the upregulation of hepcidin mRNA and downregulation of Fpn1 protein expression in the spleen and liver of LPS-treated mice. Mechanistically, this effect was attributed to RocA's ability to inhibit the IL-6/STAT3 pathway, resulting in the suppression of hepcidin mRNA and subsequent increase in Fpn1 and TfR1 expression in LPS-treated macrophages. Moreover, RocA inhibited the elevation of the cellular labile iron pool (LIP) and reactive oxygen species (ROS) induced by LPS in RAW264.7 cells. These findings reveal a pivotal mechanism underlying the roles of RocA in modulating iron homeostasis and also provide a candidate natural product on alleviating AI.

Bone marrow Tfr2 deletion improves the therapeutic efficacy of the activin-receptor ligand trap RAP-536 in β-thalassemic mice

β-thalassemia is a disorder characterized by anemia, ineffective erythropoiesis (IE), and iron overload, whose treatment still requires improvement. The activin receptor-ligand trap Luspatercept, a novel therapeutic option for β-thalassemia, stimulates erythroid differentiation inhibiting the transforming growth factor β pathway. However, its exact mechanism of action and the possible connection with erythropoietin (Epo), the erythropoiesis governing cytokine, remain to be clarified. Moreover, Luspatercept does not correct all the features of the disease, calling for the identification of strategies that enhance its efficacy. Transferrin receptor 2 (TFR2) regulates systemic iron homeostasis in the liver and modulates the response to Epo of erythroid cells, thus balancing red blood cells production with iron availability. Stimulating Epo signaling, hematopoietic Tfr2 deletion ameliorates anemia and IE in Hbbth3/+ thalassemic mice. To investigate whether hematopoietic Tfr2 inactivation improves the efficacy of Luspatercept, we treated Hbbth3/+ mice with or without hematopoietic Tfr2 (Tfr2BMKO/Hbbth3/+) with RAP-536, the murine analog of Luspatercept. As expected, both hematopoietic Tfr2 deletion and RAP-536 significantly ameliorate IE and anemia, and the combined approach has an additive effect. Since RAP-536 has comparable efficacy in both Hbbth3/+ and Tfr2BMKO/Hbbth3/+ animals, we propose that the drug promotes erythroid differentiation independently of TFR2 and EPO stimulation. Notably, the lack of Tfr2, but not RAP-536, can also attenuate iron-overload and related complications. Overall, our results shed further light on the mechanism of action of Luspatercept and suggest that strategies aimed at inhibiting hematopoietic TFR2 might improve the therapeutic efficacy of activin receptor-ligand traps.

Nutritional status and its relationship with COVID-19 prognosis in hemodialysis patients

Introduction

Introduction: among the groups more affected by the COVID-19 pandemic were patients undergoing chronic hemodialysis (HD) treatment due to their comorbidities, advanced age, impaired innate and adaptive immune function, and increased nutritional risk due to their underlying inflammatory state. All of these factors contribute to a higher risk of severe complications and worse outcomes compared to the general population when infected with SARS-CoV-2. Objective: the objective of this study was to describe the nutritional characteristics of and their potential association with the prognosis of COVID-19 in patients undergoing chronic HD treatment. Method: a descriptive, retrospective, observational design. All cases of COVID-19 in patients undergoing chronic treatment at the Hemodialysis Unit of Hospital de Manises, Valencia, Spain, from the start of the pandemic to before vaccination were included. Results: for that, 189 patients were studied, who received chronic HD treatment in the hospital unit, 22 patients were diagnosed with COVID-19 (12 %) in that period. The mean age was 71 years, 10 were women, the Charlson index was 6.59 points, diabetes mellitus 10, vintage HD 51.6 months, 2 patients had previously received a currently non-functioning kidney transplant, 16 had arteriovenous fistula as vascular access, and 6 had central vascular access. The mean dialysis session time was 220.14 minutes and the initial value of the single dose of the Kt/V pool was 1.7. 16 patients had body composition measurement, a strong association (p < 0.05) was identified between mortality and BMI, as well as mortality and FTI. Furthermore, the differences between deceased and surviving groups in the serum levels of various variables related to nutritional status were analyzed, finding significant differences with p < 0.05 in the value of triglycerides and ferritin. Conclusions: higher body mass index and higher body fat content, along with lower baseline levels of triglycerides and ferritin, were significantly associated with higher COVID-19 mortality in patients on chronic hemodialysis. These findings suggest that the initial nutritional status of these patients can significantly influence the prognosis of SARS-CoV-2 infection.

Comparative efficacy and safety of Chinese patent medicines of iron deficiency anemia during pregnancy: A network meta-analysis

BACKGROUND

Iron deficiency anemia (IDA) is a prevalent nutritional disorder during pregnancy. Clinical studies indicate that incorporating Chinese patent medicines (CPMs) with oral iron (OI) in treating IDA in pregnancy can reduce adverse effects and improve clinical outcomes. Nonetheless, the comparative efficacy of different CPMs remains unclear.

AIM

To assess the safety and effectiveness of different CPMs for treating IDA during pregnancy using network meta-analysis.

METHODS

We conducted a search for randomized controlled trials (RCTs) that combined CPM and OI for IDA treatment in pregnancy, spanning from 2013 to the present. Data analysis was performed using Rev Man 5.3 and Stata 14.0 on literature that satisfied the quality criteria.

RESULTS

The analysis included 45 RCTs, encompassing 4422 pregnant patients with IDA. Six CPMs were examined, including Shengxuebao Mixture, Shengxuening Tablets (SXN), Yiqi Weixue CPMs (YQWX), Jianpi Shengxue CPMs (JPSX), Yiqi Buxue Tablets, and Compound Hongyi Buxue Oral Liquid (FFHY). Findings indicated that FFHY + OI significantly improved the clinical effective rate. SXN + OI was most effective in boosting red blood cells counts and hemoglobin levels. YQWX + OI showed superior results in improving serum ferritin, and SXN + OI was most effective in increasing serum iron levels. JPSX + OI was optimal in reducing adverse pregnancy outcomes, while YQBX + OI effectively minimized adverse events. A cluster analysis suggested that SXN + OI could be the potentially optimal therapeutic regimen for IDA in pregnancy.

CONCLUSION

This study demonstrates that the combination of OI with CPMs offers better outcomes than OI alone. Based on clinical efficacy and other measured outcomes, SXN + OI emerges as the most effective treatment modality for improving the health of pregnant patients with IDA.

Iron Metabolism in the Recovery Phase of Critical Illness with a Focus on Sepsis

Iron is an essential nutrient for humans and microbes, such as bacteria. Iron deficiency commonly occurs in critically ill patients, but supplementary iron therapy is not considered during the acute phase of critical illness since it increases iron availability for invading microbes and oxidative stress. However, persistent iron deficiency in the recovery phase is harmful and has potential adverse outcomes such as cognitive dysfunction, fatigue, and cardiopulmonary dysfunction. Therefore, it is important to treat iron deficiency quickly and efficiently. This article reviews current knowledge about iron-related biomarkers in critical illness with a focus on patients with sepsis, and provides possible criteria to guide decision-making for iron supplementation in the recovery phase of those patients.

Hemochromatosis-How Not to Overlook and Properly Manage "Iron People"-A Review

Hemochromatosis (HC) is the main genetic disorder of iron overload and is regarded as metal-related human toxicosis. HC may result from HFE and rare non-HFE gene mutations, causing hepcidin deficiency or, sporadically, hepcidin resistance. This review focuses on HFE-related HC. The illness presents a strong biochemical penetrance, but its prevalence is low. Unfortunately, the majority of patients with HC remain undiagnosed at their disease-curable stage. The main aim of HC management is to prevent iron overload in its early phase and remove excess iron from the body by phlebotomy in its late stage. Raising global awareness of HC among health staff, teaching them how not to overlook early HC manifestations, and paying attention to careful patient monitoring remain critical management strategies for preventing treatment delays, upgrading its efficacy, and improving patient prognosis.

New Insight into Neuropathic Pain: The Relationship between α7nAChR, Ferroptosis, and Neuroinflammation

Neuropathic pain, which refers to pain caused by a lesion or disease of the somatosensory system, represents a wide variety of peripheral or central disorders. Treating neuropathic pain is quite demanding, primarily because of its intricate underlying etiological mechanisms. The central nervous system relies on microglia to maintain balance, as they are associated with serving primary immune responses in the brain next to cell communication. Ferroptosis, driven by phospholipid peroxidation and regulated by iron, is a vital mechanism of cell death regulation. Neuroinflammation can be triggered by ferroptosis in microglia, which contributes to the release of inflammatory cytokines. Conversely, neuroinflammation can induce iron accumulation in microglia, resulting in microglial ferroptosis. Accumulating evidence suggests that neuroinflammation, characterized by glial cell activation and the release of inflammatory substances, significantly exacerbates the development of neuropathic pain. By inhibiting microglial ferroptosis, it may be possible to prevent neuroinflammation and subsequently alleviate neuropathic pain. The activation of the homopentameric α7 subtype of the neuronal nicotinic acetylcholine receptor (α7nAChR) has the potential to suppress microglial activation, transitioning M1 microglia to an M2 phenotype, facilitating the release of anti-inflammatory factors, and ultimately reducing neuropathic pain. Recent years have witnessed a growing recognition of the regulatory role of α7nAChR in ferroptosis, which could be a potential target for treating neuropathic pain. This review summarizes the mechanisms related to α7nAChR and the progress of ferroptosis in neuropathic pain according to recent research. Such an exploration will help to elucidate the relationship between α7nAChR, ferroptosis, and neuroinflammation and provide new insights into neuropathic pain management.