The complex interplay of iron metabolism, reactive oxygen species, and reactive nitrogen species: insights into the potential of various iron therapies to induce oxidative and nitrosative stress

Prevalence of iron deficiency in acute and chronic heart failure according to different clinical definitions

AIMS

Iron is essential to maintain cellular energy metabolism in the myocardium. Impaired cellular iron availability negatively affects myocardial physiology and can aggravate heart failure (HF). Iron deficiency (ID) is frequently found in patients with acute and chronic HF (AHF, CHF) and associated with clinical outcome. The aim of this analysis was to assess the true ID prevalence in HF patients on the basis of different ID definitions.

METHODS

We performed a retrospective analysis of 329 AHF and 613 CHF patients, recruited between 02/2021 and 05/2022 at the Innsbruck Medical University (47%/32% female, median age 81/64 years). ID was defined according to a general definition, gastroenterology and cardiology guidelines as ferritin <30 or <45 ng/mL or <100/ng/mL (absolute ID), ferritin 30-100 or 45-150 or 100-299 ng/mL plus TSAT <20% (combined ID), and ferritin >100 or >150 or ≥300 ng/mL plus TSAT <20% (functional ID).

RESULTS

ID prevalence was significantly higher in AHF compared with CHF patients: general definition (74.8% vs. 32.6%, P < 0.001), gastroenterology guidelines (75.7% vs. 34.7%, P < 0.001), cardiology guidelines (79.9% vs. 47.3%, P < 0.001). We found distinctive differences in prevalence of ID types between the three definitions. Absolute ID prevalence was highest when applying cardiology compared with gastroenterology guidelines and general definition (AHF: 44.7% vs. 20.4% vs. 7.0%; CHF: 34.1% vs. 13.4% vs. 7.2%), while frequency of combined ID was almost equally distributed. Functional ID prevalence was highest when applying general definition compared with gastroenterology and cardiology guidelines (AHF: 34.7% vs. 23.4% vs. 11.6%; CHF: 13.1% vs. 9.0% vs. 3.4%). Out of 494 patients classified as having absolute or combined ID according to the cardiology guidelines, only 252 patients received the same classification while 107 and 135 patients were classified having no and functional ID when applying the general definition.

CONCLUSIONS

We show that ID prevalence is higher in AHF versus CHF patients in a continuous cohort of HF patients managed at the same institution over the same period of time. There were distinctive differences in detection of ID and the type of ID when applying several recommended definitions thus affecting sensitivity and specificity for absolute and functional ID detection. This may result in exclusion of patients, which may benefit from iron supplementation and inclusion of those who may not respond or even anticipate site effects. Our study calls for the urgent need of prospective trials for redefinition of ID and identification of biomarkers associated with therapeutic response to optimize patient outcomes.

Effects of Environmentally Relevant Concentrations of Roundup on Oxidative-Nitrative Stress, Cellular Apoptosis, Prooxidant-Antioxidant Homeostasis, Renin and CYP1A Expressions in Goldfish: Molecular Mechanisms Underlying Kidney Damage During Roundup Exposure

Roundup is one of the most widely used glyphosate-based harmful herbicides in the United States as well as globally, which poses a severe risk for terrestrial and aquatic organisms. In order to identify the detrimental effects of Roundup exposure in aquatic organisms, we investigated the environmentally relevant concentrations of Roundup exposure (low dose: 0.5 μg/L and high dose: 5.0 μg/L for 2 weeks) on renin expression, oxidative-nitrative stress biomarkers (e.g., 2,4-dinitrophenol, DNP; and 3-nitrotyrosine protein, NTP), prooxidant-antioxidant enzymes expressions (e.g., superoxide dismutase, SOD; and catalase, CAT), cellular apoptosis, and cytochrome P450 1A (CYP1A) mRNA levels in the kidneys of goldfish ( Carassius auratus ). Histopathological and in situ TUNEL analyses showed widespread tissue disruption (e.g., bowman's capsule shrinkage, melanin pigment formation, etc.) and induced apoptotic nuclei in the kidneys of goldfish. Immunohistochemical and quantitative real-time PCR (qRT-PCR) analyses showed a significant (p < 0.05) increase in the expression of renin, DNP, NTP, SOD, and CAT, as well as CYP1A mRNA levels in the kidneys of fish exposed to Roundup. These results suggest that environmentally relevant concentrations of Roundup disrupt kidney architecture by inducing oxidative-nitrative stress, cellular apoptosis, and change in osmoregulatory enzymes (i.e., renin) and prooxidant-antioxidant systems in the kidneys of teleost fishes.

Long non-coding RNA in the regulation of cell death in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the predominant form of primary liver cancer, accounting for 90% of all cases. Currently, early diagnosis of HCC can be achieved through serum alpha-fetoprotein detection, B-ultrasound, and computed tomography scanning; however, their specificity and sensitivity are suboptimal. Despite significant advancements in HCC biomarker detection, the prognosis for patients with HCC remains unfavorable due to tumor heterogeneity and limited understanding of its pathogenesis. Therefore, it is crucial to explore more sensitive HCC biomarkers for improved diagnosis, monitoring, and management of the disease. Long non-coding RNA (lncRNA) serves as an auxiliary carrier of genetic information and also plays diverse intricate regulatory roles that greatly contribute to genome complexity. Moreover, investigating gene expression regulation networks from the perspective of lncRNA may provide insights into the diagnosis and prognosis of HCC. We searched the PubMed database for literature, comprehensively classified regulated cell death mechanisms and systematically reviewed research progress on lncRNA-mediated cell death pathways in HCC cells. Furthermore, we prospectively summarize its potential implications in diagnosing and treating HCC.

Crosstalk Between Sickle Cell Disease and Ferroptosis

Sickle cell disease (SCD) is an inherited hemoglobin disorder that is widespread across the globe. It is characterized by a very complex pathogenesis, but at the basis of the disease is the mutation of the HBB gene, which determines the production of a mutated hemoglobin: sickle cell hemoglobin (HbS). The polymerization of HbS, which occurs when the protein is in a deoxygenated state, and the greater fragility of sickle cell red blood cells (sRBCs) determine the release of iron, free heme, and HbS in the blood, favoring oxidative stress and the production of reactive oxygen species (ROS). These features are common to the features of a new model of cell death known as ferroptosis, which is characterized by the increase of iron and ROS concentrations and by the inhibition of glutathione peroxidase 4 (GPx4) and the System Xc-. In this context, this review aims to discuss the potential molecular and biochemical pathways of ferroptosis involved in SCD, aiming to highlight possible tags involved in treating the disease and inhibiting ferroptosis.

Neurological Emergency Treatment Strategy: A Neuron-Targeted Regulation System for Reactive Oxygen Species Metabolism through Ferroptosis Modulation

Spinal cord injury (SCI) represents a significant clinical challenge. Following SCI, the implementation of protective measures for neurons is critically important. Current clinical applications of hormone pulse therapy exhibit variable efficacy and considerable side effects, highlighting an urgent need for therapeutic strategies. This study investigates the pathological conditions of ischemia and hypoxia in the SCI region, complemented by early transcriptome sequencing postinjury. Our findings suggest that targeting ferroptosis is pivotal for early neuroprotection following SCI. Aiming at the cascade effect of mitochondrial damage leading to reactive oxygen species (ROS) production, along with extensive ROS-mediated lysosomal damage during ferroptosis signaling, we developed a liposome-based system for regulating iron metabolism─DTLS@CAT. This innovative liposome is designed to specifically target neuronal mitochondria, effectively eliminate mitoROS, and modulate complex interactions among iron metabolism, mitochondria, lysosomes, and ROS to facilitate recovery from SCI.

Characterization of Choerospondias axillaris polysaccharide‑iron (III) complex and its effect on iron deficiency anemia mice

Iron deficiency anemia (IDA) is a prevalent nutritional deficiency problem. This study aimed to investigate the characteristics of Choerospondias axillaris polysaccharide-Fe (III) complex and its effect on IDA mice. CAP-Fe (III) complex was synthesized by co-thermal synthesis method with an iron content of 27.31 ± 0.97 %. The chelation of Fe3+ reduced the crystallinity, increased the thermal stability and changed the morphological features of CAP, which was evidenced by XRD, TG, and SEM analysis. The probable existence of the β-FeOOH structure was supported by the characteristic absorption peaks in the FT-IR, XRD, and Mössbauer spectra. The CAP-Fe (III) complex showed a therapeutic effect on IDA mice, confirmed by improved erythroid parameters, iron levels, and oxidative stress. The results of gene expression levels determined by RT-qPCR demonstrated that the CAP-Fe (III) complex could regulate iron metabolism homeostasis, alleviate liver inflammation, and enhance intestinal barrier function. Furthermore, the dysbiosis of intestinal microbiota induced by IDA was effectively restored by CAP-Fe (III) complex, through enriching beneficial bacteria (Firmicutes, Blautia, Oscillibacter, Colidextribacter) and depleting harmful bacteria (Actinobacteria, Proteobacteria, Parasutterella, Faecalibaculum, Escherichia-Shigella). These findings suggested that CAP-Fe (III) may serve as a novel iron supplement for treating IDA.

Evaluation of Different Polysaccharide-Iron Complex Preparations In Vitro and In Vivo

Objectives: Iron-deficiency anemia is one of the most common nutritional deficiencies worldwide. Polysaccharide-iron complexes (PICs), as novel organic iron supplements, have garnered increasing attention due to their high bioavailability, minimal gastrointestinal irritation, and favorable tolerability. However, different formulations of PICs can show significant variations in their physicochemical properties and bioavailability. These factors are crucial for clinical efficacy and safety. Methods: This study selected two formulations of polysaccharide-iron complexes: Formulation A (PIC-coated pellets) and Formulation B (PIC powders), with ferrous succinate tablets (Formulation C) used as a control. The focus was on evaluating the molecular weight of the polysaccharides, the levels of free iron, and the dissolution across various dissolution media. Physicochemical properties were compared through particle size analysis, dissolution rate testing, and free iron content determination. Additionally, the pharmacokinetic properties of the two PIC formulations were assessed in a beagle dog model of iron-deficiency anemia. Results: Significant differences were observed in particle appearance and content structure between the two PIC formulations. Formulation A, prepared using pellet technology, exhibited a uniform particle size distribution. Its dissolution rate in acidic environments was significantly lower than that of Formulation B. In simulated gastric fluid, the cumulative iron dissolution rate of Formulation A was less than 15% within two hours, while that of Formulation B exceeded 50%, with substantial batch-to-batch variability. In various dissolution media, Formulation A released 12% of its dissolved iron content in gastric fluid within two hours. In contrast, the absolute free iron content of Formulation B was 8.5 times higher than that of Formulation A in simulated gastric fluid. In the beagle dog model of iron-deficiency anemia, Formulation A showed significantly higher bioavailability, which suggests that the pellet preparation technology improves both the acid resistance and bioavailability of the PIC formulation. Conclusions: The study revealed that Formulation A, prepared using pellet technology, possesses unique quality characteristics. This technology significantly reduces the release of free iron from PICs due to gastric acid action, potentially minimizing gastrointestinal irritation. Moreover, the pellet preparation process improves the acid resistance and bioavailability of PIC formulations, offering a more effective therapeutic option for iron-deficiency anemia. Future research may further explore the potential applications of pellet technology in other iron supplement formulations.

Inflammation-driven NF-κB signaling represses ferroportin transcription in macrophages via HDAC1 and HDAC3

ABSTRACT

Anemia of inflammation is a prevalent comorbidity in patients with chronic inflammatory disorders. Inflammation causes hypoferremia and iron-restricted erythropoiesis by limiting ferroportin (FPN)-mediated iron export from macrophages that recycle senescent erythrocytes. Macrophage cell surface expression of FPN is reduced by hepcidin-induced degradation and/or by repression of FPN (Slc40a1) transcription via cytokine and Toll-like receptor (TLR) stimulation. Although the mechanisms underlying hepcidin-mediated control of FPN have been extensively studied, those inhibiting Slc40a1 messenger RNA (mRNA) expression remain unknown. We applied targeted RNA interference and pharmacological screens in macrophages stimulated with the TLR2/6 ligand FSL1 and identified critical signaling regulators of Slc40a1 mRNA repression downstream of TLRs and NF-κB signaling. Interestingly, the NF-κB regulatory hub is equally relevant for Slc40a1 mRNA repression driven by the TLR4 ligand lipopolysaccharide, the cytokine tumor necrosis factor β/lymphotoxin-alpha (LTA), and heat-killed bacteria. Mechanistically, macrophage stimulation with heat-killed Staphylococcus aureus recruits the histone deacetylases (HDACs) HDAC1 and HDAC3 to the antioxidant response element (ARE) located in the Slc40a1 promoter. Accordingly, pretreatment with a pan-HDAC inhibitor abrogates Slc40a1 mRNA repression in response to inflammatory cues, suggesting that HDACs act downstream of NF-κB to repress Slc40a1 transcription. Consistently, recruitment of HDAC1 and HDAC3 to the Slc40a1 ARE after stimulation with heat-killed S aureus is dependent on NF-κB signaling. These results support a model in which the ARE integrates the transcriptional responses of Slc40a1 triggered by signals from redox, metabolic, and inflammatory pathways. This work identifies the long-sought mechanism of Slc40a1 transcriptional downregulation upon inflammation, paving the way for therapeutic interventions at this critical juncture.

Intravenous iron treatment fuels chronic kidney disease-induced arterial media calcification in rats

Arterial media calcification is a severe cardiovascular complication commonly manifesting in patients with chronic kidney disease (CKD). Patients with CKD frequently undergo intravenous iron therapy to address iron deficiency. Iron is suggested to be sequestered in vascular cells, potentially leading to oxidative (lipid) stress and cell death, which are recognized as key contributors to arterial calcification. The objective of this study was to investigate the effect of intravenous iron administration on CKD-induced arterial media calcification. Therefore, adenine-induced CKD rats were treated intravenously with iron and checked for arterial iron deposition and calcification, as well as for ferritin and lipid peroxidation markers. Additionally, arterial sections from patients with CKD who were dialysis dependent were analyzed for these parameters. This study showed that intravenous iron administration in CKD rats led to arterial iron deposition and a lipid peroxidation signature. CKD-induced arterial calcification was increased upon iron treatment and correlated with arterial iron accumulation and lipid peroxidation markers. Patients with CKD who were dialysis dependent showed arterial iron accumulation and elevated lipid peroxidation, but a direct correlation with arterial calcification was lacking. Taken together, iron treatment is suggested as a potential contributor to the calcification process, instead of being a predominant factor, thereby emphasizing the complexity of arterial calcification as a multifactorial disease. © 2024 The Author(s). The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

The Global Prevalence of Iron Deficiency in Collegiate Athletes: A Systematic Review and Meta-Analysis

Athletes are at high risk of iron deficiency even without anemia. In this systematic review and meta-analysis that included 17,519 athletes in 122 references from 23 countries, participating in 62 unique sports over a 41-year timeframe, approximately 53.9% of student-athletes were found to be hypoferritinemic (ferritin concentration below 50 mcg/L) with 23.0% percent showing absolute iron deficiency based on current definitions (ferritin concentration below 20 mcg/L). These findings strongly suggest that changes in clinical practice guidelines are warranted to enable routine screening for iron deficiency among adolescent and collegiate athletes.

Iron Deficiency in Collegiate Athletes Obtaining Preparticipation Hemoglobinopathy Screening in the Upper Midwest

OBJECTIVE

Iron and other biologically important metals are essential to mitochondrial function but are not routinely evaluated. Their equilibrium is critical to the optimal performance of cells with high metabolic activity such as neurons, cardiomyocytes, and skeletal myocytes. Teenagers are at a high risk of iron deficiency even without anemia. Metal ion imbalances can cause cognitive impairments, muscle weakness, and sudden cardiac death. We aim to assess the current prevalence of iron deficiency among collegiate athletes in the Upper Midwest.

METHODS

Our study is a multicenter, retrospective chart review of outpatient clinics in a regional healthcare system between January 2012 and December 2023, and a national public database between 2017 and March 2020. We reviewed the ferritin concentrations of regional collegiate athletes having preparticipation sport evaluations and nationally in the NHANES database.

RESULTS

We identified 643 unique individuals aged 16-21 years with 253 having ferritin screening. Iron deficiency (ferritin <20 mcg/L) was present in 24.5% and hypoferritinemia (ferritin <50 mcg/L) was present in 66.7% of collegiate athletes. From the NHANES database, 12.7% of active sampled participants aged 16-21 years were iron deficient.

CONCLUSION

Our study findings suggest the need for universal screening for iron deficiency among collegiate athletes given the high prevalence of iron deficiency in both the retrospective chart review and NHANES database analysis. Given the critical role of metal ion homeostasis to optimal mitochondrial function, these findings may warrant the inclusion of ferritin testing in cardiac, neurological, and skeletal muscle evaluations.

Systematic and comprehensive insights into HIF-1 stabilization under normoxic conditions: implications for cellular adaptation and therapeutic strategies in cancer

Hypoxia-inducible factors (HIFs) are essential transcription factors that orchestrate cellular responses to oxygen deprivation. HIF-1α, as an unstable subunit of HIF-1, is usually hydroxylated by prolyl hydroxylase domain enzymes under normoxic conditions, leading to ubiquitination and proteasomal degradation, thereby keeping low levels. Instead of hypoxia, sometimes even in normoxia, HIF-1α translocates into the nucleus, dimerizes with HIF-1β to generate HIF-1, and then activates genes involved in adaptive responses such as angiogenesis, metabolic reprogramming, and cellular survival, which presents new challenges and insights into its role in cellular processes. Thus, the review delves into the mechanisms by which HIF-1 maintains its stability under normoxia including but not limited to giving insights into transcriptional, translational, as well as posttranslational regulation to underscore the pivotal role of HIF-1 in cellular adaptation and malignancy. Moreover, HIF-1 is extensively involved in cancer and cardiovascular diseases and potentially serves as a bridge between them. An overview of HIF-1-related drugs that are approved or in clinical trials is summarized, highlighting their potential capacity for targeting HIF-1 in cancer and cardiovascular toxicity related to cancer treatment. The review provides a comprehensive insight into HIF-1's regulatory mechanism and paves the way for future research and therapeutic development.

Transcriptomic Analysis and Experimental Verification of Ferroptosis Signature Genes in Osteoarthritis

Osteoarthritis is a systemic disease that primarily damages articular cartilage and also affects the synovium, ligaments, and bone tissues. The key mechanisms involved are chondrocyte death and degradation of the extracellular matrix. This study aims to identify differentially expressed genes (DEGs) associated with ferroptosis and investigate their roles in the development of osteoarthritis. We used several methods, such as transcriptomic data analysis, gene enrichment analysis, protein-protein interaction network construction, animal model experiments, and immune cell infiltration analysis. Our examination of the GSE114007 dataset uncovered 2614 DEGs, including 1300 that were upregulated and 1314 that were downregulated. From these, we identified eight ferroptosis-related DEGs (FRGs-DEGs). Functional enrichment analysis showed that these genes are significant for cellular migration and tissue remodeling. They are particularly involved in the HIF-1 and PPAR signaling pathways. Additionally, our immune cell infiltration analysis indicated an increase in M0 and M2 macrophages in osteoarthritis samples, while levels of eosinophils and memory B cells were notably decreased. The receiver operating characteristic curve analysis identified GJA1, TIMP Metallopeptidase Inhibitor 1 (TIMP1), and DPP4 as potential biomarkers for osteoarthritis diagnosis, with area under the curve of 0.91, 0.85, and 0.83, respectively. Moreover, RT-qPCR validation in an osteoarthritis rat model confirmed the upregulation of TIMP1, supporting our bioinformatics results. In summary, our study identifies key FRGs-DEGs and their potential roles in osteoarthritis. This research provides new insights into the disease's molecular mechanisms and suggests innovative therapeutic targets for clinical intervention. Future research should aim to include larger patient cohorts and clinical validation to improve the applicability of these findings.

Toward Understanding the Anticancer Activity of the Phytocompounds from Eugenia uniflora Using Molecular Docking, in silico Toxicity and Dynamics Studies

Background

The Surinam cherry, Eugenia uniflora belongs to the family Myrtaceae, an edible fruit-bearing medicinal plant with various biological properties. Several anticancer studies have been conducted on its essential oils while the non-essential oil compounds including phenolics, flavonoids, and carotenoids have not been fully investigated.

Purpose

Therefore, the study evaluated the in silico anticancer potentials of phenolic, flavonoid, and carotenoid compounds of E. uniflora against the MDM2 and Bcl-xL proteins, which are known to promote cancer cell growth and malignancy. The physicochemical parameters, validation, cytotoxicity, and mutagenicity of the polyphenols were determined using the SwissADME, pkCSM, ProTox-II, and vNN-ADMET online servers respectively. Lastly, the promising phytocompounds were validated using molecular dynamics (MD) simulation.

Results

An extensive literature search resulted in the compilation of forty-four (44) polyphenols from E. uniflora. Top-rank among the screened polyphenols is galloylastragalin, which exhibited a binding energy score of -8.7 and -8.5 kcal/mol with the hydrophobic interactions (Ala93, Val141) and (Leu54, Val93, Ile99), as well as hydrogen bond interactions (Tyr195) and (Gln72) of the proteins Bcl-xL and MDM2 respectively. A complete in silico toxicity assessment revealed that the compounds, galloylastragalin, followed by myricetin, resveratrol, p-Coumaroylquinic acid, and cyanidin-3-O-glucoside, were potentially non-mutagenic, non-carcinogenic, non-cytotoxic, and non-hepatotoxic. During the 120 ns MD simulations, the RMSF analysis of galloylastragalin- MDM2 (complex 1) and galloylastragalin- Bcl-xL (complex 2) showed the fewest fluctuations, indicating the conformational stability of the respective complexes.

Conclusion

This study has shown that polyphenol compounds of E. uniflora led by galloylastragalin, are potent inhibitors of the MDM2 and Bcl-xL cancer proteins. Thus, they may be considered as candidate polyphenols for further anticancer studies.

Design, synthesis, and biological evaluation of novel halogenated chlorido[N,N'-bis(salicylidene)-1,2-bis(3-methoxyphenyl)ethylenediamine]iron(III) complexes as anticancer agents

Iron(III) complexes based on N,N´-bis(salicylidene)ethylenediamine (salene) scaffolds have demonstrated promising anticancer features like induction of ferroptosis, an iron dependent cell death. Since poor cellular uptake limits their therapeutical potential, this study aimed to enhance the lipophilic character of chlorido[N,N'-bis(salicylidene)-1,2-bis(3-methoxyphenyl)ethylenediamine]iron(III) complexes by introducing lipophilicity improving ligands such as fluorine (X1), chlorine (X2) and bromine (X3) in 5-position in the salicylidene moieties. After detailed characterization the binding to nucleophiles, logP values and cellular uptake were determined. The complexes were further evaluated regarding their biological activity on MDA-MB 231 mammary carcinoma, the non-tumorous SV-80 fibroblast, HS-5 stroma and MCF-10A mammary gland cell lines. Stability of the complexes in aqueous and biological environments was proven by the lack of interactions with amino acids and glutathione. Cellular uptake was positively correlated with the logP values, indicating that higher lipophilicity enhanced cellular uptake. The complexes induced strong antiproliferative and antimetabolic effects on MDA-MB 231 cells, but were inactive on all non-malignant cells tested. Generation of mitochondrial reactive oxygen species, increase of lipid peroxidation and induction of both ferroptosis and necroptosis were identified as mechanisms of action. In conclusion, halogenation of chlorido[N,N'-bis(salicylidene)-1,2-bis(3-methoxyphenyl)ethylenediamine]iron(III) complexes raises their lipophilic character resulting in improved cellular uptake.

Gastric Ulcer From Prolonged Oral Iron Therapy: A Case Report and Literature Review

Iron deficiency is a leading cause of anemia worldwide and is commonly treated with oral iron supplements, which are known for their GI side effects. We present a case of a 66-year-old woman with a history of GI bleeding and multiple comorbidities who developed a gastric ulcer after prolonged oral iron therapy. Although GI side effects are frequent with iron supplements, ulceration is rare, with only a few documented cases. Endoscopic and histopathological evaluations identified iron deposition in the ulcer bed, confirming the diagnosis. Discontinuing the oral iron led to the resolution of symptoms. This case underscores the importance of recognizing and managing iron-induced gastric ulcers to ensure safe and effective treatment of iron deficiency.

Iron homeostasis, recycling and vulnerability in the stressed kidney: A neglected dimension of iron-deficient heart failure

The available evidence suggests that the kidney may contribute importantly to the development of an iron deficiency state in patients with heart failure and may be injured by therapeutic efforts to achieve iron repletion. The exceptional workload of the proximal renal tubule requires substantial quantities of iron for ATP synthesis, which it derives from Fe3+ bound to transferrin in the bloodstream. Following ferrireduction, Fe2+ is conveyed by divalent transporters (e.g. DMT1) out of the endosome of the proximal renal tubule, and highly reactive Fe2+ can be directed to the mitochondria, sequestered safely in a ferritin nanocage or exported through the actions of hepcidin-inhibitable ferroportin. The actions of ferroportin, together with transferrin endocytosis and DMT1-mediated transport, play a key role in the recycling of iron from the tubular fluid into the bloodstream and preventing the loss of filtered iron in the urine. Activation of endogenous neurohormonal systems and proinflammatory signalling in heart failure decrease megalin-mediated uptake and DMT1 expression, and increase hepcidin-mediated suppression of ferroportin, promoting the loss of iron in the urine and contributing to the development of an iron deficiency state. Furthermore, the failure of ferroportin-mediated efflux at the basolateral membrane heightens the susceptibility of the renal tubules to cytosolic excesses of Fe2+, causing lipid peroxidation and synchronized cell death (ferroptosis) through the iron-dependent free radical theft of electrons from lipids in the cell membrane. Ferroptosis is a central mechanism to most disorders that can cause acute and chronic kidney disease. Short-term bolus administration of intravenous iron can cause oxidative stress and is accompanied by markers of renal injury. Experimentally, long-term maintenance of an iron-replete state is accompanied by accelerated loss of nephrons, oxidative stress, inflammation and fibrosis. Intravenous iron therapy increases glomerular filtration rate rapidly in patients with heart failure (perhaps because of a haemodynamic effect) but not in patients with chronic kidney disease, and the effects of intravenous iron on the progression of renal dysfunction in the long-term trials - AFFIRM-AHF, IRONMAN and HEART-FID - have not yet been reported. Given the potential role of dysregulated renal iron homeostasis in the pathogenesis of iron deficiency and the known vulnerability of the kidney to intravenous iron, the appropriate level of iron repletion with respect to the risk of acute and chronic kidney injury in patients with heart failure requires further study.

Impacts of oxidative stress and anti-oxidants on the development, pathogenesis, and therapy of sickle cell disease: A comprehensive review

Sickle cell disease (SCD) is the most severe monogenic hemoglobinopathy caused by a single genetic mutation that leads to repeated polymerization and depolymerization of hemoglobin resulting in intravascular hemolysis, cell adhesion, vascular occlusion, and ischemia-reperfusion injury. Hemolysis causes oxidative damage indirectly by generating reactive oxygen species through various pathophysiological mechanisms, which include hemoglobin autoxidation, endothelial nitric oxide synthase uncoupling, reduced nitric oxide bioavailability, and elevated levels of asymmetric dimethylarginine. Red blood cells have a built-in anti-oxidant system that includes enzymes like sodium dismutase, catalase, and glutathione peroxidase, along with free radical scavenging molecules, such as vitamin C, vitamin E, and glutathione, which help them to fight oxidative damage. However, these anti-oxidants may not be sufficient to prevent the effects of oxidative stress in SCD patients. Therefore, in line with a recent FDA request that the focus to be placed on the development of innovative therapies for SCD that address the root cause of the disease, there is a need for therapies that target oxidative stress and restore redox balance in SCD patients. This review summarizes the current state of knowledge regarding the role of oxidative stress in SCD and the potential benefits of anti-oxidant therapies. It also discusses the challenges and limitations of these therapies and suggests future directions for research and development.

Genetic Determined Iron Starvation Signature in Friedreich's Ataxia

BACKGROUND

Early studies in cellular models suggested an iron accumulation in Friedreich's ataxia (FA), yet findings from patients are lacking.

OBJECTIVES

The objective is to characterize systemic iron metabolism, body iron storages, and intracellular iron regulation in FA patients.

METHODS

In FA patients and matched healthy controls, we assessed serum iron parameters, regulatory hormones as well as the expression of regulatory proteins and iron distribution in peripheral blood mononuclear cells (PBMCs). We applied magnetic resonance imaging with R2*-relaxometry to quantify iron storages in the liver, spleen, and pancreas. Across all evaluations, we assessed the influence of the genetic severity as expressed by the length of the shorter GAA-expansion (GAA1).

RESULTS

We recruited 40 FA patients (19 women). Compared to controls, FA patients displayed lower serum iron and transferrin saturation. Serum ferritin, hepcidin, mean corpuscular hemoglobin and mean corpuscular volume in FA inversely correlated with the GAA1-repeat length, indicating iron deficiency and restricted availability for erythropoiesis with increasing genetic severity. R2*-relaxometry revealed a reduction of splenic and hepatic iron stores in FA. Liver and spleen R2* values inversely correlated with the GAA1-repeat length. FA PBMCs displayed downregulation of ferritin and upregulation of transferrin receptor and divalent metal transporter-1 mRNA, particularly in patients with >500 GAA1-repeats. In FA PBMCs, intracellular iron was not increased, but shifted toward mitochondria.

CONCLUSIONS

We provide evidence for a previously unrecognized iron starvation signature at systemic and cellular levels in FA patients, which is related to the underlying genetic severity. These findings challenge the use of systemic iron lowering therapies in FA. © 2024 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Dopamine‑iron homeostasis interaction rescues mitochondrial fitness in Parkinson's disease

Imbalances of iron and dopamine metabolism along with mitochondrial dysfunction have been linked to the pathogenesis of Parkinson's disease (PD). We have previously suggested a direct link between iron homeostasis and dopamine metabolism, as dopamine can increase cellular uptake of iron into macrophages thereby promoting oxidative stress responses. In this study, we investigated the interplay between iron, dopamine, and mitochondrial activity in neuroblastoma SH-SY5Y cells and human induced pluripotent stem cell (hiPSC)-derived dopaminergic neurons differentiated from a healthy control and a PD patient with a mutation in the α-synuclein (SNCA) gene. In SH-SY5Y cells, dopamine treatment resulted in increased expression of the transmembrane iron transporters transferrin receptor 1 (TFR1), ferroportin (FPN), and mitoferrin2 (MFRN2) and intracellular iron accumulation, suggesting that dopamine may promote iron uptake. Furthermore, dopamine supplementation led to reduced mitochondrial fitness including decreased mitochondrial respiration, increased cytochrome c control efficiency, reduced mtDNA copy number and citrate synthase activity, increased oxidative stress and impaired aconitase activity. In dopaminergic neurons derived from a healthy control individual, dopamine showed comparable effects as observed in SH-SY5Y cells. The hiPSC-derived PD neurons harboring an endogenous SNCA mutation demonstrated altered mitochondrial iron homeostasis, reduced mitochondrial capacity along with increased oxidative stress and alterations of tricarboxylic acid cycle linked metabolic pathways compared with control neurons. Importantly, dopamine treatment of PD neurons promoted a rescue effect by increasing mitochondrial respiration, activating antioxidant stress response, and normalizing altered metabolite levels linked to mitochondrial function. These observations provide evidence that dopamine affects iron homeostasis, intracellular stress responses and mitochondrial function in healthy cells, while dopamine supplementation can restore the disturbed regulatory network in PD cells.

Tissue Iron Distribution in Anemic Patients with End-Stage Kidney Disease: Results of a Pilot Study

Background/Objectives: Anemia is a frequent multifactorial co-morbidity in end-stage kidney disease (ESKD) associated with morbidity and poor QoL. Apart from insufficient erythropoietin formation, iron deficiency (ID) contributes to anemia development. Identifying patients in need of iron supplementation with current ID definitions is difficult since no good biomarker is available to detect actual iron needs. Therefore, new diagnostic tools to guide therapy are needed. Methods: We performed a prospective cohort study analyzing tissue iron content with MRI-based R2*-relaxometry in 20 anemic ESKD patients and linked it with iron biomarkers in comparison to 20 otherwise healthy individuals. Results: ESKD patients had significantly higher liver (90.1 s-1 vs. 36.1 s-1, p < 0.001) and spleen R2* values (119.8 s-1 vs. 19.3 s-1, p < 0.001) compared to otherwise healthy individuals, while their pancreas and heart R2* values did not significantly differ. Out of the 20 ESKD patients, 17 had elevated spleen and 12 had elevated liver R2* values. KDIGO guidelines (focusing on serum iron parameters) would recommend iron supplementation in seven patients with elevated spleen and four patients with elevated liver R2* values. Conclusions: These findings highlight that liver and especially spleen iron concentrations are significantly higher in ESKD patients compared to controls. Tissue iron overload diverged from classical iron parameters suggesting need of iron supplementation. Measurement of MRI-guided tissue iron distribution might help guide treatment of anemic ESKD patients.

Oxidative Status, Iron Plasma Levels in Venous Thrombosis Patients

Exaggerated clot induces venous thrombosis (VTE); oxidative stress (OxS) can to be postulated as additional risk factor. This study evaluates firstly OxS by measuring surrogate biomarkers (malondialdehyde-MDA, 4-hydroxinonenal-4-HNE, superoxide desmutase enzyme (SOD)), secondly the iron (Fe) plasma level and thirdly the hepcidin protein (Hep) level in patients with VTE. A case control study was performed enrolling twenty hospitalized patients and an equal number of healthy individuals. In VTE patients, the following results were found. The MDA was 8.38 ± 0.5 µM/L, the 4-HNE measured 2.75 ± 0.03 µM/L and the SOD was 0.025 ± 0.01 U/mL. The I was 73.10 ± 10 µg/dL and the He was 4.77 ± 0.52 ng/mL. In the control group, the MDA measured 5.5 ± 0.6 µM/L, the 4-HNE 2.24 ± 0.021 µM/L and the SOD 0.08 ± 0.12 U/mL. The Hep was 2.1 ± 0.55 ng/mL and the Fe was 88.2 ± 9.19 µg/dL. Differences were statistically significant. Results suggest that in VTE there is activated OxS, Fe deregulation and over-production of Hep. Fe deregulation induces OxS, leading both to inflammation in the clot activator and stimulation of the pro-thrombotic status. The study highlights OxS and Fe and their regulation as intriguing indicators for risk of VTE.

Critical re-evaluation of the identification of iron deficiency states and effective iron repletion strategies in patients with chronic heart failure

According to current guidelines, iron deficiency is defined by a serum ferritin level <100 ng/ml or a transferrin saturation (TSAT) <20% if the serum ferritin level is 100-299 μg/L. These criteria were developed to encourage the use of intravenous iron as an adjunct to erythropoiesis-stimulating agents in the treatment of renal anaemia. However, in patients with heart failure, these criteria are not supported by any pathophysiological or clinical evidence that they identify an absolute or functional iron deficiency state. A low baseline TSAT-but not serum ferritin level-appears to be a reliable indicator of the effect of intravenous iron to reduce major heart failure events. In randomized controlled trials, intravenous iron decreased the risk of cardiovascular death or total heart failure hospitalization in patients with a TSAT <20% (risk ratio 0.67 [0.49-0.92]) but not in patients with a TSAT ≥20% (risk ratio 0.99 [0.74-1.30]), with the magnitude of the risk reduction being proportional to the severity of hypoferraemia. Patients who were enrolled in clinical trials solely because they had a serum ferritin level <100 μg/L showed no significant benefit on heart failure outcomes, and it is noteworthy that serum ferritin levels of 20-300 μg/L lie entirely within the range of normal values for healthy adults. Current guidelines reflect the eligibility criteria of clinical trials, which inadvertently adopted unvalidated criteria to define iron deficiency. Reliance on these guidelines would lead to the treatment of many patients who are not iron deficient (serum ferritin level <100 μg/L but normal TSAT) and ignores the possibility of iron deficiency in patients with a low TSAT but with serum ferritin level of >300 μg/L. Importantly, analyses of benefit based on trial eligibility-driven guidelines substantially underestimate the magnitude of heart-failure-event risk reduction with intravenous iron in patients who are truly iron deficient. Based on all available data, we recommend a new mechanism-based and trial-tested approach that reflects the totality of evidence more faithfully than the historical process adopted by clinical investigators and by the guidelines. Until additional evidence is forthcoming, an iron deficiency state in patients with heart failure should be defined by a TSAT <20% (as long as the serum ferritin level is <400 μg/L), and furthermore, the use of a serum ferritin level <100 μg/L alone as a diagnostic criterion should be discarded.

Herbal medicines provide regulation against iron overload in cardiovascular diseases: Informing future applications

ETHNOPHARMACOLOGICAL RELEVANCE

Iron is an essential micronutrient for maintaining physiological activities, especially for highly active cardiomyocytes. Inappropriate iron overload or deficiency has a significant impact on the incidence and severity of cardiovascular diseases (CVD). Iron overload exerts potentially deleterious effects on doxorubicin (DOX) cardiomyopathy, atherosclerosis, and myocardial ischemia-reperfusion injury (MI/RI) by participating in lipid peroxides production. Notably, iron overload-associated cell death has been defined as a possible mechanism for ferroptosis. At present, some traditional herbal medicines and extracts have been included in the study of regulating iron overload and the subsequent therapeutic effect on CVD.

AIM OF THE STUDY

To give an outline of iron metabolism and ferroptosis in cardiomyocytes and to focus on herbal medicines and extracts to prevent iron overload in CVD.

MATERIALS AND METHODS

Literature information was systematically collected from ScienceDirect, PubMed, Google Scholar, Web of Science, China National Knowledge Infrastructure, WanFang data, as well as classic books and clinical reports.

RESULTS

After understanding the mechanism of iron overload on CVD, this paper reviews the therapeutic function of various herbal medicines in eliminating iron overload in CVD. These include Chinese herbal compound prescriptions (Salvia miltiorrhiza injection, Gegen Qinlian decoction, Tongxinluo, Banxia-Houpu decoction), plant extracts, phenylpropanoids, flavonoids, terpenoids, and polyphenols. Among them, flavonoids are considered to be the most promising compounds because of their prominent iron chelation. Mechanically, these herbal medicines act on the Nrf2 signaling pathway, AMPK signaling pathway, and KAT5/GPX4 signaling pathway, thereby attenuating iron overload and lipid peroxidation in CVD.

CONCLUSION

Our review provides up-to-date information on herbal medicines that exert cardiovascular protective effects by modulating iron overload and ferroptosis. These herbal medicines hold promise as a template for preventing iron overload in CVD.

Imbalance of Iron Availability and Demand in Patients With Acute and Chronic Heart Failure

BACKGROUND

Iron deficiency (ID) is a frequent comorbidity in patients with acute (AHF) and chronic heart failure (CHF) associated with morbidity and death. We aimed to better characterize iron homeostasis in patients with heart failure applying different biomarkers and to evaluate the accuracy of current ID definition by the European Society of Cardiology/American College of Cardiology/American Heart Association to indicate tissue iron availability and demand.

METHODS AND RESULTS

We performed a retrospective cohort study investigating 277 patients with AHF and 476 patients with CHF between February 2021 and May 2022. Patients with AHF had more advanced ID than patients with CHF, reflected by increased soluble transferrin receptor and soluble transferrin receptor-ferritin index, and lower ferritin, serum iron, transferrin saturation, hepcidin, and reticulocyte hemoglobin. Decreased iron availability or increased tissue iron demand, reflected by increased soluble transferrin receptor-ferritin index and decreased reticulocyte hemoglobin, was found in 84.1% (AHF) and 28.0% (CHF) with absolute ID and in 50.0% (AHF) and 10.5% (CHF) with combined ID according to the current European Society of Cardiology/American College of Cardiology/American Heart Association-based ID definition. Low hepcidin expression as an indicator of systemic ID was found in 91.1% (AHF) and 80.4% (CHF) of patients with absolute ID and in 32.3% (AHF) and 18.8% (CHF) of patients with combined ID. ID definitions with higher specificity reduce the need for iron supplementation by 25.5% in patients with AHF and by 65.6% in patients with CHF.

CONCLUSIONS

Our results suggest that the current European Society of Cardiology/American College of Cardiology/American Heart Association-based ID definition might overestimate true ID, particularly in CHF. More stringent thresholds for ID could more accurately identify patients with heart failure with reduced tissue iron availability who benefit from intravenous iron supplementation.

Immune consequences of exercise in hypoxia: A narrative review

Immune outcomes are key mediators of many health benefits of exercise and are determined by exercise type, dose (frequency/duration, intensity), and individual characteristics. Similarly, reduced availability of ambient oxygen (hypoxia) modulates immune functions depending on the hypoxic dose and the individual capacity to respond to hypoxia. How combined exercise and hypoxia (e.g., high-altitude training) sculpts immune responses is not well understood, although such combinations are becoming increasingly popular. Therefore, in this paper, we summarize the impact on immune responses of exercise and of hypoxia, both independently and together, with a focus on specialized cells in the innate and adaptive immune system. We review the regulation of the immune system by tissue oxygen levels and the overlapping and distinct immune responses related to exercise and hypoxia, then we discuss how they may be modulated by nutritional strategies. Mitochondrial, antioxidant, and anti-inflammatory mechanisms underlie many of the adaptations that can lead to improved cellular metabolism, resilience, and overall immune functions by regulating the survival, differentiation, activation, and migration of immune cells. This review shows that exercise and hypoxia can impair or complement/synergize with each other while regulating immune system functions. Appropriate acclimatization, training, and nutritional strategies can be used to avoid risks and tap into the synergistic potentials of the poorly studied immune consequences of exercising in a hypoxic state.

Iron-carbohydrate complexes treating iron anaemia: Understanding the nano-structure and interactions with proteins through orthogonal characterisation

Intravenous (IV) iron-carbohydrate complexes are widely used nanoparticles (NPs) to treat iron deficiency anaemia, often associated with medical conditions such as chronic kidney disease, heart failure and various inflammatory conditions. Even though a plethora of physicochemical characterisation data and clinical studies are available for these products, evidence-based correlation between physicochemical properties of iron-carbohydrate complexes and clinical outcome has not fully been elucidated yet. Studies on other metal oxide NPs suggest that early interactions between NPs and blood upon IV injection are key to understanding how differences in physicochemical characteristics of iron-carbohydrate complexes cause variance in clinical outcomes. We therefore investigated the core-ligand structure of two clinically relevant iron-carbohydrate complexes, iron sucrose (IS) and ferric carboxymaltose (FCM), and their interactions with two structurally different human plasma proteins, human serum albumin (HSA) and fibrinogen, using a combination of cryo-scanning transmission electron microscopy (cryo-STEM), x-ray diffraction (XRD), small-angle x-ray scattering (SAXS) and small-angle neutron scattering (SANS). Using this orthogonal approach, we defined the nano-structure, individual building blocks and surface morphology for IS and FCM. Importantly, we revealed significant differences in the surface morphology of the iron-carbohydrate complexes. FCM shows a localised carbohydrate shell around its core, in contrast to IS, which is characterised by a diffuse and dynamic layer of carbohydrate ligand surrounding its core. We hypothesised that such differences in carbohydrate morphology determine the interaction between iron-carbohydrate complexes and proteins and therefore investigated the NPs in the presence of HSA and fibrinogen. Intriguingly, IS showed significant interaction with HSA and fibrinogen, forming NP-protein clusters, while FCM only showed significant interaction with fibrinogen. We postulate that these differences could influence bio-response of the two formulations and their clinical outcome. In conclusion, our study provides orthogonal characterisation of two clinically relevant iron-carbohydrate complexes and first hints at their interaction behaviour with proteins in the human bloodstream, setting a prerequisite towards complete understanding of the correlation between physicochemical properties and clinical outcome.

Developing garlic polysaccharide-Fe (III) complexes using garlic pomace to provide enhanced iron-supplementing activity in vivo

This study investigated the potential of garlic polysaccharides (GPs) from garlic pomace as iron carriers. The obtained GP-Fe (III) complexes had a higher molecular weight (5646 Da) and more fructose (90.46 %) than the GPs did and contained 9.7 % Fe (III). GPs were mainly composed of → 2)-β-d-Fruf (1 → and → 2)-β-d-Fruf (6 → residues, and their interactions with Fe (III) reduced the crystallinity, increased the thermal stability, and altered the morphological features through targeting the OH stretching vibrations of the hydroxyl groups and affecting the COC and OCO structures. The GP-Fe (III) complexes had high stability under simulated gastrointestinal digestion system and showed better therapeutic effects on iron deficiency anemia in mice than FeSO4 did, evidenced by improved hematological parameters, restored iron levels, and attenuated oxidative damage. Thus, GP-Fe (III) complexes are promising as novel Fe (III) supplements for Fe-deficient individuals, and promote the high-value utilization of garlic pomace.

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

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

Ferroptosis in cancer: From molecular mechanisms to therapeutic strategies

Ferroptosis is a non-apoptotic form of regulated cell death characterized by the lethal accumulation of iron-dependent membrane-localized lipid peroxides. It acts as an innate tumor suppressor mechanism and participates in the biological processes of tumors. Intriguingly, mesenchymal and dedifferentiated cancer cells, which are usually resistant to apoptosis and traditional therapies, are exquisitely vulnerable to ferroptosis, further underscoring its potential as a treatment approach for cancers, especially for refractory cancers. However, the impact of ferroptosis on cancer extends beyond its direct cytotoxic effect on tumor cells. Ferroptosis induction not only inhibits cancer but also promotes cancer development due to its potential negative impact on anticancer immunity. Thus, a comprehensive understanding of the role of ferroptosis in cancer is crucial for the successful translation of ferroptosis therapy from the laboratory to clinical applications. In this review, we provide an overview of the recent advancements in understanding ferroptosis in cancer, covering molecular mechanisms, biological functions, regulatory pathways, and interactions with the tumor microenvironment. We also summarize the potential applications of ferroptosis induction in immunotherapy, radiotherapy, and systemic therapy, as well as ferroptosis inhibition for cancer treatment in various conditions. We finally discuss ferroptosis markers, the current challenges and future directions of ferroptosis in the treatment of cancer.

Edwardsiella piscicida causes iron storage disorders by an autophagy pathway in fish monocytes/macrophages

Edwardsiella piscicida (E. piscicida) is a gram-negative pathogen that survives in intracellular environment. Currently, the interplay between E. piscicida and host cells has not been completely explored. In this study, we found that E. piscicida disturbed iron homeostasis in grass carp monocytes/macrophages to maintain its own growth. Further investigation revealed the bacteria induced an increase of intracellular iron, which was subjected to the degradation of ferritin. Moreover, the autophagy inhibitor impeded the degradation of ferritin and increase of intracellular iron in E. piscicida-infected monocytes/macrophages, implying possible involvement of autophagy response in the process of E. piscicida-broken iron homeostasis. Along this line, confocal microscopy observed that E. piscicida elicited the colocalization of ferritin with LC3-positive autophagosome in the monocytes/macrophages, indicating that E. piscicida mediated the degradation of ferritin possibly through the autophagic pathway. These results deepened our understanding of the interaction between E. piscicida and fish cells, hinting that the disruption of iron homeostasis was an important factor for pathogenicity of E. piscicida. They also indicated that autophagy was a possible mechanism governing intracellular iron metabolism in response to E. piscicida infection and might offer a new avenue for anti-E. piscicida strategies in the future.

Zinc Supplementation Enhances the Hematopoietic Activity of Erythropoiesis-Stimulating Agents but Not Hypoxia-Inducible Factor-Prolyl Hydroxylase Inhibitors

Since zinc is involved in many aspects of the hematopoietic process, zinc supplementation can reduce erythropoiesis-stimulating agents (ESAs) in patients undergoing hemodialysis. However, it remains unclear whether hypoxia-inducible factor-prolyl hydroxylase inhibitors (HIF-PHIs) have similar reduction effects. HIF-PHI stabilizes HIF, which promotes hematopoiesis, although HIF-1α levels are downregulated by zinc. This study aimed to investigate the effect of zinc supplementation on the hematopoietic effect of HIF-PHI in patients undergoing hemodialysis. Thirty patients undergoing maintenance hemodialysis who underwent periods of treatment with roxadustat or darbepoetin alfa during the past 3 years were retrospectively observed. Participants who underwent periods with and without zinc supplementation were selected, with nine treated with darbepoetin alfa and nine treated with roxadustat. Similarly to the ESA responsiveness index (ERI), the hematopoietic effect of zinc supplementation was determined by the HIF-PHI responsiveness index (HRI), which was calculated by dividing the HIF-PHI dose (mg/week) by the patient's dry weight (kg) and hemoglobin level (g/L). Zinc supplementation significantly increased ERI (p < 0.05), but no significant change was observed (p = 0.931) in HRI. Although zinc supplementation did not significantly affect HRI, adequate zinc supplementation is required to alleviate concerns such as vascular calcification and increased serum copper during the use of HIF-PHI.

Association between iron deficiency anemia and subsequent stomach and colorectal cancer diagnosis in Germany

PURPOSE

Iron deficiency anemia (IDA) is the most common form of anemia worldwide, resulting in a high burden of disease. Accumulating evidence suggests that IDA is associated with the development of gastrointestinal (GI) cancers.

METHODS

Data from the IDA database (IQVIA) of primary care practices in Germany of adult patients first diagnosed with IDA between January 2005 and December 2021 were retrospectively analyzed and compared with a 1:1 propensity score-adjusted cohort without IDA. Study outcomes were first stomach cancer or colorectal cancer (CRC) diagnosis up to 10 years after the index date as a function of IDA.

RESULTS

A total of 122,502 individuals with IDA and 122,502 individuals without IDA were included. The 10-year cumulative incidence of CRC was 1.4% in the IDA patients compared to 0.8% in the cohort without IDA (p < 0.001). Regression analysis revealed a significant association between IDA and subsequent CRC (HR 2.05; 95% CI 1.83-2.30). Stomach cancer was diagnosed in 0.3% of IDA patients compared to 0.2% in the non-IDA cohort during the 10-year follow-up period (p = 0.002). However, this was significant only in the age group > 80 years (HR 2.73; 95% CI 1.60-4.67) and in men (HR 1.90; 95% CI 1.38-2.61).

CONCLUSION

These findings add to the literature and suggest an association between IDA and GI cancers. The extent to which this association is due to GI bleeding or other pathophysiological processes that may be caused by IDA requires further investigation, particularly experimental studies.

Artesunate Inhibits the Growth of Insulinoma Cells via SLC7A11/ GPX4-mediated Ferroptosis

BACKGROUND

Artesunate (ART) has been recognized to induce ferroptosis in various tumor phenotypes, including neuroendocrine tumors. We aimed to investigate the effects of ART on insulinoma and the underlying mechanisms by focusing on the process of ferroptosis.

METHODS

The CCK8 and colony formation assays were conducted to assess the effectiveness of ART. Lipid peroxidation, glutathione, and intracellular iron content were determined to validate the process of ferroptosis, while ferrostatin-1 (Fer-1) was employed as the inhibitor of ferroptosis. Subcutaneous tumor models were established and treated with ART. The ferroptosis-associated proteins were determined by western blot and immunohistochemistry assays. Pathological structures of the liver were examined by hematoxylin-eosin staining.

RESULTS

ART suppressed the growth of insulinoma both in vitro and in vivo. Insulinoma cells treated by ART revealed signs of ferroptosis, including increased lipid peroxidation, diminished glutathione levels, and ascending intracellular iron. Notably, ART-treated insulinoma cells exhibited a decline in the expressions of catalytic component solute carrier family 7 member 11 (SLC7A11) and glutathione peroxidase 4 (GPX4). These alterations were negated by Fer-1. Moreover, no hepatotoxicity was observed upon the therapeutic dose of ART.

CONCLUSION

Artesunate might regulate ferroptosis of insulinoma cells through the SLC7A11/GPX4 pathway.

Mineral Supplements in Ageing

With advancing age, achievement of dietary adequacy for all nutrients is increasingly difficult and this is particularly so for minerals. Various factors impede mineral acquisition and absorption including reduced appetite, depressed gastric acid production and dysregulation across a range of signalling pathways in the intestinal mucosa. Minerals are required in sufficient levels since they are critical for the proper functioning of metabolic processes in cells and tissues, including energy metabolism, DNA and protein synthesis, immune function, mobility, and skeletal integrity. When uptake is diminished or loss exceeds absorption, alternative approaches are required to enable individuals to maintain adequate mineral levels. Currently, supplementation has been used effectively in populations for the restoration of levels of some minerals like iron, zinc, and calcium, but these may not be without inherent challenges. Therefore, in this chapter we review the current understanding around the effectiveness of mineral supplementation for the minerals most clinically relevant for the elderly.

Total iron binding capacity: an independent predictor of prognosis for pulmonary arterial hypertension in systemic lupus erythematosus

OBJECTIVE

To investigate the role of parameters of iron metabolism in systemic lupus erythematosus (SLE) patients with pulmonary arterial hypertension (PAH).

METHOD

This was a prospective observational study recruiting patients diagnosed with systemic lupus erythematosus-associated pulmonary arterial hypertension (SLE-PAH). Patients with other factors that might lead to PAH were excluded from the study. All patients were assessed for PAH every 1-3 months and were followed up for 6 months. The primary outcome was considered improved if the grade of risk stratification declined at the endpoint; otherwise, it was considered unimproved.

RESULTS

In total, 29 patients with SLE-PAH were included in this study. The mean of serum ferritin was higher than normal, and total iron binding capacity (TIBC) decreased in 48% of patients. Correlation analyses showed that serum iron (SI) was negatively correlated with World Health Organization functional class (WHO-FC) (r = -0.409, p = 0.028), and positively correlated with Six-Minute Walk Test distance (6MWD) (r = 0.427, p = 0.021) and tricuspid annular plane systolic excursion (TAPSE) (r = 0.388, p = 0.037). Primary outcomes improved in 12 patients at the endpoint, and univariate logistic regression analyses indicated that TIBC was associated with improved primary outcomes in patients with SLE-PAH (odds ratio 12.00, 95% confidence interval 1.90-75.72).

CONCLUSION

SI was negatively correlated with WHO-FC, and positively correlated with 6MWD and TAPSE. Furthermore, TIBC was associated with improved outcomes of patients with SLE-PAH, which could be an independent predictor of prognosis. Further research is needed to verify the findings.

One advantageous reflection of iron metabolism in context of normal physiology and pathological phases

PURPOSE (BACKGROUND)

The presented review is an updating of Iron metabolism in context of normal physiology and pathological phases. Iron is one of the vital elements in humans and associated into proteins as a component of heme (e.g. hemoglobin, myoglobin, cytochromes proteins, myeloperoxidase, nitric oxide synthetases), iron sulfur clusters (e.g. respiratory complexes I-III, coenzyme Q10, mitochondrial aconitase, DNA primase), or other functional groups (e.g. hypoxia inducible factor prolyl hydroxylases). All these entire iron-containing proteins ar e needed for vital cellular and organismal functions together with oxygen transport, mitochondrial respiration, intermediary and xenobiotic metabolism, nucleic acid replication and repair, host defense, and cell signaling.

METHODS (METABOLIC STRATEGIES)

Cells have developed metabolic strategies to import and employ iron safely. Regulatory process of iron uptake, storage, intracellular trafficking and utilization is vital for the maintenance of cellular iron homeostasis. Cellular iron utilization and intracellular iron trafficking pathways are not well established and very little knowledge about this. The predominant organs, which are associated in the metabolism of iron, are intestine, liver, bone marrow and spleen. Iron is conserved, recycled and stored. The reduced bioavailability of iron in humans has developed extremely efficient mechanisms for iron conservation. Prominently, the losses of iron cannot considerably enhance through physiologic mechanisms, even if iron intake and stores become excessive. Loss of iron is balanced or maintained from dietary sources.

RESULTS (OUTCOMES)

Numerous physiological abnormalities are associated with impaired iron metabolism. These abnormalities are appeared in the form of several diseases. There are duodenal ulcer, inflammatory bowel disease, sideroblastic anaemia, congenital dyserythropoietic anemias and low-grade myelodysplastic syndromes. Hereditary hemochromatosis and anaemia are two chronic diseases, which are responsible for disturbing the iron metabolism in various tissues, including the spleen and the intestine. Impairment in hepatic hepcidin synthesis is responsible for chronic liver disease, which is grounding from alcoholism or viral hepatitis. This condition directs to iron overload that can cause further hepatic damage. Iron has important role in several infectious diseases are tuberculosis, malaria trypanosomatid diseases and acquired immunodeficiency syndrome (AIDS). Iron is also associated with Systemic lupus erythematosus [SLE], cancer, Alzheimer's disease (AD) and post-traumatic epilepsy.

CONCLUSION

Recently, numerous research studies are gradually more dedicated in the field of iron metabolism, but a number of burning questions are still waiting for answer. Cellular iron utilization and intracellular iron trafficking pathways are not well established and very little knowledge about this. Increased information of the physiology of iron homeostasis will support considerate of the pathology of iron disorders and also make available the support to advance treatment.

The multivalency game ruling the biology of immunity

Macrophages play a crucial role in our immune system, preserving tissue health and defending against harmful pathogens. This article examines the diversity of macrophages influenced by tissue-specific functions and developmental origins, both in normal and disease conditions. Understanding the spectrum of macrophage activation states, especially in pathological situations where they contribute significantly to disease progression, is essential to develop targeted therapies effectively. These states are characterized by unique receptor compositions and phenotypes, but they share commonalities. Traditional drugs that target individual entities are often insufficient. A promising approach involves using multivalent systems adorned with multiple ligands to selectively target specific macrophage populations based on their phenotype. Achieving this requires constructing supramolecular structures, typically at the nanoscale. This review explores the theoretical foundation of engineered multivalent nanosystems, dissecting the key parameters governing specific interactions. The goal is to design targeting systems based on distinct cell phenotypes, providing a pragmatic approach to navigating macrophage heterogeneity's complexities for more effective therapeutic interventions.

(-)-α-bisabolol exerts neuroprotective effects against pentylenetetrazole-induced seizures in rats by targeting inflammation and oxidative stress

Epilepsy is the most common neurological disorder which is accompanied with behavioral and psychiatric alternations. Current evidences have shown that (-)-α-bisabolol (BSB) possess anti-inflammatory and antioxidative effects in several animal studies. Here, we conducted present study to evaluate its neuroprotective effects against pentylenetetrazole (PTZ)-induced seizures in rats. We used fifty male rats and they were randomly assigned into 5 groups control, BSB100, PTZ, BSB50 + PTZ, BSB100 + PTZ. The animals intraperitoneally received PTZ (45 mg/kg) for ten consecutive days to induce epilepsy model. BSB in doses of 50 and 100 mg/kg was administrated orally one hour before PTZ administration for ten days. The elevated plus maze (EPM) test was carried out to assess anxiety-like behavior. The seizure intensity was evaluated according to modifies Racine's convulsion scale (RCS). Y-maze and passive avoidance were utilized to assess working memory and aversive memory. The expression of pro-inflammatory cytokines and oxidative stress factors were measured using the enzyme-linked immunosorbent assay (ELISA). The neuronal cell loss in the hilar region was assessed using Nissl staining. Results showed that PTZ-treated rats had more seizure intensity, anxiety-like behavior, memory deficits, higher levels of TNF-α, IL-1β, and oxidative markers. Pre-treatment with BSB 100 significantly inhibited seizure intensity, anxiety-like behavior, and memory deficits; reduced levels of TNF-α, IL-1β, and MDA oxidative markers. Collectively, outcome of this work shows that BSB at the dose of 100 mg/kg may exert neuroprotective effects by mitigating seizures, oxidative stress, and neuroinflammation, and ameliorates memory and anxiety disorders in the PTZ-induced seizure rats.

Hydroxyl radical generations form the physiologically relevant Fenton-like reactions

Iron(II) species can participate in the Fenton and Fenton-like reactions to generate the hydroxyl radical that can oxidatively damage biomolecules and induce oxidative stress in biological systems. Many diseases, including neurodegeneration, cardiovascular disease and cancer, are associated with oxidative stress. However, it is proposed recently that hydroxyl radical would not be generated from the Fenton reaction under physiological conditions and thus would not cause oxidative stress in biological systems. This proposal may cause confusion for understanding oxidative stress and can also have impact on therapeutic strategies for the diseases associated with oxidative stress. In this Mini-review, the up-to-date convincing evidences of hydroxyl radical generation from the physiologically relevant Fenton-like reactions of the iron(II) complexes with physiological ligands in human blood plasma, including histidine, citrate and phosphate, are succinctly reviewed. The oxidative damages caused by hydroxyl radical to biomolecules and cells are briefly summarized. These findings strongly challenge the above proposal.

Reactive X (where X = O, N, S, C, Cl, Br, and I) species nanomedicine

Reactive oxygen, nitrogen, sulfur, carbonyl, chlorine, bromine, and iodine species (RXS, where X = O, N, S, C, Cl, Br, and I) have important roles in various normal physiological processes and act as essential regulators of cell metabolism; their inherent biological activities govern cell signaling, immune balance, and tissue homeostasis. However, an imbalance between RXS production and consumption will induce the occurrence and development of various diseases. Due to the considerable progress of nanomedicine, a variety of nanosystems that can regulate RXS has been rationally designed and engineered for restoring RXS balance to halt the pathological processes of different diseases. The invention of radical-regulating nanomaterials creates the possibility of intriguing projects for disease treatment and promotes advances in nanomedicine. In this comprehensive review, we summarize, discuss, and highlight very-recent advances in RXS-based nanomedicine for versatile disease treatments. This review particularly focuses on the types and pathological effects of these reactive species and explores the biological effects of RXS-based nanomaterials, accompanied by a discussion and the outlook of the challenges faced and future clinical translations of RXS nanomedicines.

Modulation of the nitric oxide/cGMP pathway in cardiac contraction and relaxation: Potential role in heart failure treatment

Evidence exists that heart failure (HF) has an overall impact of 1-2 % in the global population being often associated with comorbidities that contribute to increased disease prevalence, hospitalization, and mortality. Recent advances in pharmacological approaches have significantly improved clinical outcomes for patients with vascular injury and HF. Nevertheless, there remains an unmet need to clarify the crucial role of nitric oxide/cyclic guanosine 3',5'-monophosphate (NO/cGMP) signalling in cardiac contraction and relaxation, to better identify the key mechanisms involved in the pathophysiology of myocardial dysfunction both with reduced (HFrEF) as well as preserved ejection fraction (HFpEF). Indeed, NO signalling plays a crucial role in cardiovascular homeostasis and its dysregulation induces a significant increase in oxidative and nitrosative stress, producing anatomical and physiological cardiac alterations that can lead to heart failure. The present review aims to examine the molecular mechanisms involved in the bioavailability of NO and its modulation of downstream pathways. In particular, we focus on the main therapeutic targets and emphasize the recent evidence of preclinical and clinical studies, describing the different emerging therapeutic strategies developed to counteract NO impaired signalling and cardiovascular disease (CVD) development.

Ginsentide-like Coffeetides Isolated from Coffee Waste Are Cell-Penetrating and Metal-Binding Microproteins

Coffee processing generates a huge amount of waste that contains many natural products. Here, we report the discovery of a panel of novel cell-penetrating and metal ion-binding microproteins designated coffeetide cC1a-c and cL1-6 from the husk of two popular coffee plants, Coffea canephora and Coffea liberica, respectively. Combining sequence determination and a database search, we show that the prototypic coffeetide cC1a is a 37-residue, eight-cysteine microprotein with a hevein-like cysteine motif, but without a chitin-binding domain. NMR determination of cC1a reveals a compact structure that confers its resistance to heat and proteolytic degradation. Disulfide mapping together with chemical synthesis reveals that cC1a has a ginsentide-like, and not a hevein-like, disulfide connectivity. In addition, transcriptomic analysis showed that the 98-residue micrcoproten-like coffeetide precursor contains a three-domain arrangement, like ginsentide precursors. Molecular modeling, together with experimental validation, revealed a Mg2+ and Fe3+ binding pocket at the N-terminus formed by three glutamic acids. Importantly, cC1a is amphipathic with a continuous stretch of 19 apolar amino acids, which enables its cell penetration to target intracellular proteins, despite being highly negatively charged. Our findings suggest that coffee by-products could provide a source of ginsentide-like bioactive peptides that have the potential to target intracellular proteins.

Iron Regulatory Protein 1 is Required for the Propagation of Inflammation in Inflammatory Bowel Disease

Objective

Inflammatory bowel diseases (IBD) are complex disorders. Iron accumulates in the inflamed tissue of IBD patients, yet neither a mechanism for the accumulation nor its implication on the course of inflammation are known. We hypothesized that the inflammation modifies iron homeostasis, affects tissue iron distribution and that this in turn perpetuates the inflammation.

Design

This study analyzed human biopsies, animal models and cellular systems to decipher the role of iron homeostasis in IBD.

Results

We found inflammation-mediated modifications of iron distribution, and iron-decoupled activation of the iron regulatory protein (IRP)1. To understand the role of IRP1 in the course of this inflammation-associated iron pattern, a novel cellular co-culture model was established, that replicated the iron-pattern observed in vivo, and supported involvement of nitric oxide in the activation of IRP1 and the typical iron pattern in inflammation. Importantly, deletion of IRP1 from an IBD mouse model completely abolished both, the misdistribution of iron and intestinal inflammation.

Conclusion

These findings suggest that IRP1 plays a central role in the coordination of the inflammatory response in the intestinal mucosa and that it is a viable candidate for therapeutic intervention in IBD.

Body Iron Store and its Association with Risk of First Episode of Spontaneous Lower Extremity Deep Vein Thrombosis/ Pulmonary Embolism: A Case-Control Study

Background and objectives

The association between body iron stores and risk of deep vein thrombosis/ pulmonary embolism (DVT/ PE) has not been studied among Indian subjects. This study aimed to evaluate the same and also study the association between iron stores and recanalization of affected veins at week-12.

Methods

This Case-Control with follow-up study enrolled 85 consecutive adult (≥ 18 years) cases presenting with first episode of spontaneous, proximal lower extremity DVT/ PE and 170 age (± 3 years) and sex matched adult controls without DVT/ PE. Those with haemoglobin(Hb) < 9 g/dl, malignancies, serum creatinine ≥ 2 mg/dL, heart failure and concurrent infections/ inflammatory disorders were excluded. All participants underwent iron profile, serum ferritin light-chain (FtL) and hepcidin testing.

Results

Anaemia [OR = 2.3 (95% CI = 1.3-4.0), p = 0.001] and elevated RDW (RDW-CV > 15%) [OR = 2.3 (95% CI = 1.2-4.3), p = 0.012] were significantly associated with increased risk of DVT/ PE. Iron deficiency (ID, defined as serum ferritin < 30 µg/L, along with TSAT < 20%) was not associated with DVT/ PE risk [OR = 0.8 (95% CI = 0.4-1.7), p > 0.05]. Serum FtL in the highest quartile (> 75th centile) was associated with higher risk of DVT/ PE (OR = 5, 95% CI = 2.6-9.6) and levels < 25th centile with protection against DVT/ PE (OR = 0.1, 95% CI = 0.01-0.32), compared to levels between 25th and 75th centiles (referent range). Highest DVT/ PE risk was associated with FtL > 90th centile [OR≈12 (95% CI = 3.9-37.2)]. No associations were noted between serum hepcidin and DVT/ PE risk and ID and DVT recanalization at week-12.

Conclusion

Higher iron stores, rather than ID, were associated with increased risk of DVT/ PE among those with Hb ≥ 9 g/dL. Anaemia and elevated RDW were also associated with risk of DVT/ PE. ID was not associated with poorer DVT recanalization at week-12.

Brain Iron Metabolism, Redox Balance and Neurological Diseases

The incidence of neurological diseases, such as Parkinson's disease, Alzheimer's disease and stroke, is increasing. An increasing number of studies have correlated these diseases with brain iron overload and the resulting oxidative damage. Brain iron deficiency has also been closely linked to neurodevelopment. These neurological disorders seriously affect the physical and mental health of patients and bring heavy economic burdens to families and society. Therefore, it is important to maintain brain iron homeostasis and to understand the mechanism of brain iron disorders affecting reactive oxygen species (ROS) balance, resulting in neural damage, cell death and, ultimately, leading to the development of disease. Evidence has shown that many therapies targeting brain iron and ROS imbalances have good preventive and therapeutic effects on neurological diseases. This review highlights the molecular mechanisms, pathogenesis and treatment strategies of brain iron metabolism disorders in neurological diseases.

Theranostic Role of Iron Oxide Nanoparticle for Treating Renal Anemia: Evidence of Efficacy and Significance by MRI, Histology and Biomarkers

(1) Background: Increasing attention has been given to applying nanosized iron oxide nanoparticles (IOPs) to treat iron deficiency anemia (IDA). Chronic kidney disease (CKD) patients who suffer from IDA often need long-term iron supplements. We aim to evaluate the safety and therapeutic effect of MPB-1523, a novel IOPs, in anemic CKD mice and to monitor iron storage by magnetic resonance (MR) imaging. (2) Methods: MPB-1523 was intraperitoneally delivered to the CKD and sham mice, and blood were collected for hematocrit, iron storage, cytokine assays, and MR imaging throughout the study. (3) Results: The hematocrit levels of CKD and sham mice dropped initially but increased gradually to reach a steady value 60 days after IOP injection. The body iron storage indicator, ferritin gradually rose and total iron-binding capacity stabilized 30 days after IOP injection. No significant inflammation or oxidative stress were observed in both groups. By T2-weighted MR imaging, the liver signal intensity gradually increased in both groups but was more pronounced in the CKD group, indicating aggressive utilization of MPB-1523. MR imaging, histology and electron microscopy showed MPB-1523 is liver-specific. (4) Conclusions: MPB-1523 can serve as a long-term iron supplement and is monitored by MR imaging. Our results have strong translatability to the clinic.

Oxidative Stress-Induced Cellular Senescence: Is Labile Iron the Connecting Link?

Cellular senescence, a cell state characterized by a generally irreversible cell cycle arrest, is implicated in various physiological processes and a wide range of age-related pathologies. Oxidative stress, a condition caused by an imbalance between the production and the elimination of reactive oxygen species (ROS) in cells and tissues, is a common driver of cellular senescence. ROS encompass free radicals and other molecules formed as byproducts of oxygen metabolism, which exhibit varying chemical reactivity. A prerequisite for the generation of strong oxidizing ROS that can damage macromolecules and impair cellular function is the availability of labile (redox-active) iron, which catalyzes the formation of highly reactive free radicals. Targeting labile iron has been proven an effective strategy to counteract the adverse effects of ROS, but evidence concerning cellular senescence is sparse. In the present review article, we discuss aspects of oxidative stress-induced cellular senescence, with special attention to the potential implication of labile iron.

Iron Complexes with Antarctic Krill-Derived Peptides Show Superior Effectiveness to Their Original Protein-Iron Complexes in Mice with Iron Deficiency Anemia

Antarctic krill protein-iron complex and peptide-iron complex were acquired to investigate their iron bioavailability, expression of iron-regulated genes, and in vivo antioxidant capacity. Results indicated that the Antarctic krill peptide-iron complex significantly increased the hemoglobin (Hb), serum iron (SI), and iron contents in the liver and spleen in iron-deficiency anemia (IDA) mice (p < 0.05) compared with those of the Antarctic krill protein-iron complex. Despite the gene expressions of the divalent metal transporter 1(DMT1), the transferrin (Tf), and the transferrin receptor (TfR) being better regulated by both Antarctic krill peptide-iron complex and protein-iron complex, the relative iron bioavailability of the Antarctic krill peptide-iron complex group (152.53 ± 21.05%) was significantly higher than that of the protein-iron complex group (112.75 ± 9.60%) (p < 0.05). Moreover, Antarctic krill peptide-iron complex could enhance the antioxidant enzyme activities of superoxidase dismutase (SOD) and glutathione peroxidase (GSH-Px), reduce the malondialdehyde (MDA) level in IDA mice compared with the protein-iron complex, and reduce the cell damage caused by IDA. Therefore, these results indicated that Antarctic krill peptide-iron complex could be used as a highly efficient and multifunctional iron supplement.