Mechanism and intervention measures of iron side effects on the intestine

Ferroptosis: the potential key roles in idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic progressive interstitial lung disease characterized by recurrent injury to alveolar epithelial cells, epithelial-mesenchymal transition, and fibroblast activation, which leads to excessive deposition of extracellular matrix (ECM) proteins. However, effective preventative and therapeutic interventions are currently lacking. Ferroptosis, a unique form of iron-dependent lipid peroxidation-induced cell death, exhibits distinct morphological, physiological, and biochemical features compared to traditional programmed cell death. Recent studies have revealed a close relationship between iron homeostasis and the pathogenesis of pulmonary interstitial fibrosis. Ferroptosis exacerbates tissue damage and plays a crucial role in regulating tissue repair and the pathological processes involved. It leads to recurrent epithelial injury, where dysregulated epithelial cells undergo epithelial-mesenchymal transition via multiple signaling pathways, resulting in the excessive release of cytokines and growth factors. This dysregulated environment promotes the activation of pulmonary fibroblasts, ultimately culminating in pulmonary fibrosis. This review summarizes the latest advancements in ferroptosis research and its role in the pathogenesis and treatment of IPF, highlighting the significant potential of targeting ferroptosis for IPF management. Importantly, despite the rapid developments in this emerging research field, ferroptosis studies continue to face several challenges and issues. This review also aims to propose solutions to these challenges and discusses key concepts and pressing questions for the future exploration of ferroptosis.

A metal-polyphenol network-based iron supplement with improved stability and reduced gastrointestinal toxicity for iron deficiency anemia therapy

Iron deficiency anemia (IDA) is a global health concern, particularly affecting women and children of reproductive age. Although oral iron supplements are the standard treatment for IDA, their bioavailability is often compromised by food interactions, and they are associated with significant gastrointestinal side effects. To overcome these limitations, we developed a novel iron nano-supplement, TA-Fe NPs, based on metal-polyphenol networks (MPNs) formed through the coordination of tannic acid (TA) and Fe3+. These uniform nanoparticles (∼190 nm) offer enhanced chemical stability and reduced food interference compared to traditional iron supplements. The polyphenolic TA component provides antioxidant properties, effectively mitigating oxidative stress and inflammation induced by free iron ions. To further improve stability and intestinal absorption, TA-Fe NPs were encapsulated in an enteric coating (TA-Fe@L100) to protect against acidic conditions in the stomach. In a mouse model of IDA, TA-Fe@L100 demonstrated superior therapeutic efficacy compared to FeSO4, including improvements in hematological parameters, organ iron storage, and gut microbiota balance. Importantly, TA-Fe@L100 alleviated common gastrointestinal side effects associated with iron supplementation, presenting a promising alternative for IDA treatment. Our findings suggest that TA-Fe@L100 is a cost-effective and biocompatible oral iron supplement with minimal side effects, offering significant potential for broader clinical application in the management of IDA.

Changyanning tablet alleviates Crohn's disease by inhibiting GPX4-mediated ferroptosis

ETHNOPHARMACOLOGICAL RELEVANCE

Changyanning tablets (CYN) are a marketed traditional Chinese medicine composed of Diijincao (Euphorbia humifusa Willd.), Jinmaoercao (Hedyotis chrysotricha (Palib.) Merr.), Zhangshugen (root of Cinnamomum camphora (L.) J.Presl), Xiangru (Elsholtzia ciliate (Thunb.) Hyl.), and Fengxiangshuye (leaf of Liquidambar formosana Hance). They possess the functions of clearing heat, removing dampness, and regulating qi. CYN is used for the treatment of diarrhea and dysentery caused by damp heat in the large intestine, with symptoms such as diarrhea, or stools with pus and blood, tenesmus, abdominal pain and distension, acute and chronic gastroenteritis, diarrhea, bacterial diarrhea, and indigestion in children.

AIM OF THE STUDY

This study aims to explore the intervention effects of CYN on Crohn's disease (CD) and its potential mechanisms.

MATERIALS AND METHODS

The therapeutic effect and potential mechanism of CYN on CD were investigated based on the 2,4,6-Trinitrobenzenesulfonic acid solution (TNBS)-induced rat model. In vivo and in vitro experiments confirmed that CYN can alleviate CD by inhibiting GPX4-mediated ferroptosis. siRNA was used to knock down GPX4 for reverse validation. Finally, active components of CYN inhibiting ferroptosis were identified using UPLC-MS and the RSL3-induced HCoEpiC ferroptosis cell model.

RESULTS

CYN significantly improved ferroptosis-related indicators (GSH, MDA, GPX4, and SLC7A11) in the colons of TNBS-induced CD rats. Screening with three ferroptosis inducers (RSL3, FINO2, and erastin) revealed that CYN was most effective against RSL3 (a ferroptosis inducer targeting GPX4)-induced apoptosis. Subsequently, the resistance effect of CYN on RSL3-induced ferroptosis was confirmed in vitro. Further in vivo experiments showed that CYN alleviated local CD-like intestinal injury induced by RSL3 enema. siRNA knockdown of GPX4 in HCoEpiC cells further validated GPX4 as major target of CYN in inhibiting ferroptosis. Finally, UPLC-MS and in vitro experiments identified rutin, rosmarinic acid, and kaempferol-3-O-sophoroside as key active components of CYN for inhibiting ferroptosis.

CONCLUSIONS

CYN alleviates CD by inhibiting GPX4-mediated ferroptosis, highlighting its clinical potential for treating CD and enhancing the understanding of the pathogenic and therapeutic mechanisms associated with CD.

Amomum villosum Lour. alleviates pre-eclampsia by inducing enrichment of Bifidobacterium bifidum through vanillic acid to inhibit placental ferroptosis

ETHNOPHARMACOLOGICAL RELEVANCE

Amomum villosum Lour. (AVL), a traditional Chinese medicine, is widely used to pregnancy-related vomiting and prevent miscarriage. Pre-eclampsia (PE) is a severe pregnancy syndrome. Recent studies have demonstrated interactions between PE and the digestive system. However, it is uncertain that AVL against PE was associated with the gut.

AIM OF THE STUDY

The current research examined the curative impact of AVL on PE and underly mechanisms based on the gut-placenta axis.

MATERIALS AND METHODS

A water decoction of AVL (WOA) was extracted in boiling water, and then the decoction was converted into dried particles by freeze drying. An NG-nitro-L-arginine methyl ester (L-NAME)-induced PE mouse model was established and the preventative activity of WOA was evaluated. Furthermore, the gut microbial composition and structure were analyzed using 16S rRNA gene sequencing. Fecal microbiota transplantation (FMT) experiment was applied to confirm the efficacy of gut microbiota remodeled by WOA.

RESULTS

WOA presented protective efficacy against PE. Notably, WOA induced a significant decrease in maternal hypertension and urine protein levels and promoted fetal intrauterine growth in a dose-dependent manner, thereby improving adverse pregnancy outcomes. Moreover, WOA modulated the angiogenic imbalance by decreasing the ratio between sFlt-1 (soluble fms-like tyrosine kinase 1) and PlGF (placental growth factor) to repair placental injury and inhibited placental ferroptosis by increasing the protein levels of FPN1, FTH1, xCT, and GPX4. Tight junction proteins (ZO-1, Occludin, Claudin1) in the placenta and colon were significantly upregulated by WOA, leading to enhanced placental and gut barriers. WOA rescued intestinal dysbiosis by enriching Bifidobacterium and Akkermansia. Fecal microbiota transplantation (FMT) experiments revealed that the protection of WOA on placenta and gut were dependent on the gut microbial composition. Furthermore, supplementation with both Bifidobacterium bifidum (B. bifidum) and vanillic acid (VA, the major component of WOA) ameliorated PE symptoms. Intriguingly, results from both in vivo and in vitro analyses indicated that the B. bifidum population was enriched by VA.

CONCLUSIONS

This research is the first to demonstrate that WOA prevents PE by enriching Bifidobacterium bifidum, strengthening the gut-placenta barrier, and inhibiting placental ferroptosis. Our findings provide compelling evidence for the vital involvement of the gut-placental axis in the protection of AVL on PE, presenting a novel target for the clinic.

Electroacupuncture attenuates ferroptosis by promoting Nrf2 nuclear translocation and activating Nrf2/SLC7A11/GPX4 pathway in ischemic stroke

OBJECTIVE

Electroacupuncture has been shown to play a neuroprotective role following ischemic stroke, but the underlying mechanism remains poorly understood. Ferroptosis has been shown to play a key role in the injury process. In the present study, we wanted to explore whether electroacupuncture could inhibit ferroptosis by promoting nuclear factor erythroid-2-related factor 2 (Nrf2) nuclear translocation.

METHODS

The ischemic stroke model was established by middle cerebral artery occlusion/reperfusion (MCAO/R) in adult rats. These rats have been randomly divided into the EA + MCAO/R group, the MCAO/R group, the EA + MCAO/R + Brusatol group (the inhibitor of Nrf2), and the EA + MCAO/R + DMSO group, and the Sham group. The EA + MCAO/R group, EA + MCAO/R + Brusatol group, and the EA + MCAO/R + DMSO group received EA intervention 24 h after modeling for 7 consecutive days. The behavioral function was evaluated by Neurologic severity score (NSS), Garcia score, Foot-fault Test, and Rotarod Test. The infarct volume was detected by TTC staining, and the neuronal damage was observed by Nissl staining. The levels of Fe2+, reactive oxygen species (ROS), superoxide dismutase (SOD), and malondialdehyde (MDA) were measured by ELISA. The immunofluorescence and Western blotting were used to detect the expression of Total Nrf2, p-Nrf2, Nuclear Nrf2, and Cytoplasmic Nrf2, and the essential ferroptosis proteins, including glutathione peroxidase 4 (GPX4), solute carrier family 7 member 11 (SLC7A11) and ferritin heavy chain 1 (FTH1). The mitochondria were observed by transmission electron microscopy (TEM).

RESULTS

Electroacupuncture improved neurological deficits in rats model of MCAO/R, decreased the brain infarct volume, alleviated neuronal damage, inhibited the Fe2+, ROS, and MDA accumulation, increased SOD levels, increased the expression of GPX4, SLC7A11 and FTH1, and rescued injured mitochondria. Especially, we found that the electroacupuncture up-regulated the expression of Nrf2, and promoted phosphorylation of Nrf2 and nuclear translocation, However, Nrf2 inhibitor Brusatol reversed the neuroprotective effect of electroacupuncture.

CONCLUSION

Electroacupuncture can alleviate cerebral I/R injury-induced ferroptosis by promoting Nrf2 nuclear translocation. It is expected that these data will provide novel insights into the mechanisms of electroacupuncture protecting against cerebral I/R injury and potential targets underlying ferroptosis in the stroke.

Endoplasmic reticulum stress in intestinal microecology: A controller of antineoplastic drug-related cardiovascular toxicity

Endoplasmic reticulum (ER) stress is extensively studied as a pivotal role in the pathological processes associated with intestinal microecology. In antineoplastic drug treatments, ER stress is implicated in altering the permeability of the mechanical barrier, depleting the chemical barrier, causing dysbiosis, exacerbating immune responses and inflammation in the immune barrier. Enteric dysbiosis and intestinal dysfunction significantly affect the circulatory system in various heart disorders. In antineoplastic drug-related cardiovascular (CV) toxicity, ER stress constitutes a web of relationships in the host-microbiome symbiotic regulatory loop. Therefore, understanding the holobiont perspective will help de-escalate spatial and temporal restrictions. This review investigates the role of ER stress-mediated gut microecological alterations in antineoplastic treatment-induced CV toxicity.

Levodopa-induced dyskinesia: brain iron deposition as a new hypothesis

Parkinson's disease (PD) is a common neurodegenerative disease in the older adults. The main pathological change in PD is the degenerative death of dopamine (DA) neurons in the midbrain substantia nigra, which causes a significant decrease in the DA content of the striatum. However, the exact etiology of this pathological change remains unclear. Genetic factors, environmental factors, aging, and oxidative stress may be involved in the degenerative death of dopaminergic neurons in PD. Pharmacological treatment using levodopa (L-DOPA) remains the main treatment for PD. Most patients with PD consuming L-DOPA for a long time usually develop levodopa-induced dyskinesia (LID) after 6.5 years of use, and LID seriously affects the quality of life and increases the risk of disability. Recently, studies have revealed that cerebral iron deposition may be involved in LID development and that iron deposition has neurotoxic effects and accelerates disease onset. However, the relationship between cerebral iron deposition and LID remains unclear. Herein, we reviewed the mechanisms by which iron deposition may be associated with LID development, which are mainly related to oxidative stress, neuroinflammation, and mitochondrial and lysosomal dysfunction. Using iron as an important target, the search and development of safe and effective brain iron scavengers, and thus the alleviation and treatment of LID, has a very important scientific and clinical value, as well as a good application prospect.

Research Progress on the Mechanism of the Impact of Myofibrillar Protein Oxidation on the Flavor of Meat Products

Myofibrillar proteins primarily consist of myosin, actin, myogenin, and actomyosin. These proteins form complex networks within muscle fibers and are crucial to the physical and chemical properties of meat. Additionally, myofibrillar proteins serve as significant substrates for the adsorption of volatile flavor compounds, including aldehydes, alcohols, ketones, and sulfur and nitrogen compounds, which contribute to the overall flavor profile of meat products. A series of chemical reactions occur during the processing, storage, and transportation of meat products. Oxidation is one of the most significant reactions. Oxidative modification can alter the physical and chemical properties of proteins, ultimately impacting the sensory quality of meat products, including flavor, taste, and color. In recent years, considerable attention has been focused on the effects of protein oxidation on meat quality and its regulation. This study investigates the impact of myofibrillar protein oxidation on the sensory attributes of meat products by analyzing the oxidation processes and the factors that initiate myofibrillar protein oxidation. Additionally, it explores the control of myofibrillar protein oxidation and its implications on the sensory properties of meat products, providing theoretical insights relevant to meat processing methods and quality control procedures.

Nrf2-mediated ferroptosis inhibition: a novel approach for managing inflammatory diseases

Inflammatory diseases, including psoriasis, atherosclerosis, rheumatoid arthritis, and ulcerative colitis, are characterized by persistent inflammation. Moreover, the existing treatments for inflammatory diseases only provide temporary relief by controlling symptoms, and treatments of unstable and expensive. Therefore, new therapeutic solutions are urgently needed to address the underlying causes or symptoms of inflammatory diseases. Inflammation frequently coincides with a high level of (reactive oxygen species) ROS activation, serving as a fundamental element in numerous physiological and pathological phenotypes that can result in serious harm to the organism. Given its pivotal role in inflammation, oxidative stress, and ferroptosis, ROS represents a focal node for investigating the (nuclear factor E2-related factor 2) Nrf2 pathway and ferroptosis, both of which are intricately linked to ROS. Ferroptosis is mainly triggered by oxidative stress and involves iron-dependent lipid peroxidation. The transcription factor Nrf2 targets several genes within the ferroptosis pathway. Recent studies have shown that Nrf2 plays a significant role in three key ferroptosis-related routes, including the synthesis and metabolism of glutathione/glutathione peroxidase 4, iron metabolism, and lipid processes. As a result, ferroptosis-related treatments for inflammatory diseases have attracted much attention. Moreover, drugs targeting Nrf2 can be used to manage inflammatory conditions. This review aimed to assess ferroptosis regulation mechanism and the role of Nrf2 in ferroptosis inhibition. Therefore, this review article may provide the basis for more research regarding the treatment of inflammatory diseases through Nrf2-inhibited ferroptosis.

Antioxidant Effects of Cactus Seed Oil against Iron-Induced Oxidative Stress in Mouse Liver, Brain and Kidney

In recent times, exploring the protective potential of medicinal plants has attracted increasing attention. To fight reactive oxygen species (ROS), which are key players in hepatic, cerebral and renal diseases, scientists have directed their efforts towards identifying novel compounds with antioxidant effects. Due to its unique composition, significant attention has been given to Cactus Seed Oil (CSO). Iron, as a metal, can be a potent generator of reactive oxygen species, especially hydroxyl radicals, via the Fenton and Haber-Weiss reactions. Here, we employed ferrous sulfate (FeSO4) to induce oxidative stress and DNA damage in mice. Then, we used CSO and Colza oil (CO) and evaluated the levels of the antioxidants (superoxide dismutase [SOD], glutathione peroxidase [GPx] and glutathione [GSH]) as well as a metabolite marker for lipid peroxidation (malondialdehyde [MDA]) relating to the antioxidant balance in the liver, brain and kidney. In addition, we measured DNA damage levels in hepatic tissue and the effects of CSO on it. Our study found that iron-dependent GPx activity decreases in the liver and the kidney tissues. Additionally, while iron decreased SOD activity in the liver, it increased it in the kidney. Interestingly, iron treatment resulted in a significant increase in hepatic MDA levels. In contrast, in brain tissue, there was a significant decrease under iron treatment. In addition, we found varying protective effects of CSO in alleviating oxidative stress in the different tissues with ameliorating DNA damage after iron overload in a mouse liver model, adding compelling evidence to the protective potential of CSO.

Unveiling ferroptosis as a promising therapeutic avenue for colorectal cancer and colitis treatment

Ferroptosis is a novel type of regulated cell death (RCD) involving iron accumulation and lipid peroxidation. Since its discovery in 2012, various studies have shown that ferroptosis is associated with the pathogenesis of various diseases. Ferroptotic cell death has also been linked to intestinal dysfunction but can act as either a positive or negative regulator of intestinal disease, depending on the cell type and disease context. The continued investigation of mechanisms underlying ferroptosis provides a wealth of potential for developing novel treatments. Considering the growing prevalence of intestinal diseases, particularly colorectal cancer (CRC) and inflammatory bowel disease (IBD), this review article focuses on potential therapeutics targeting the ferroptotic pathway in relation to CRC and IBD.

Habitual Iron Supplementation Associated with Elevated Risk of Chronic Kidney Disease in Individuals with Antihypertensive Medication

The aim of this study was to examine the effects of habitual iron supplementation on the risk of CKD in individuals with different hypertensive statuses and antihypertension treatment statuses. We included a total of 427,939 participants in the UK Biobank study, who were free of CKD and with complete data on blood pressure at baseline. Cox proportional hazards regression models were used to examine the adjusted hazard ratios of habitual iron supplementation for CKD risk. After multivariable adjustment, habitual iron supplementation was found to be associated with a significantly higher risk of incident CKD in hypertensive participants (HR 1.12, 95% CI 1.02 to 1.22), particularly in those using antihypertensive medication (HR 1.21, 95% CI 1.08 to 1.35). In contrast, there was no significant association either in normotensive participants (HR 1.06, 95% CI 0.94 to 1.20) or in hypertensive participants without antihypertensive medication (HR 1.02, 95% CI 0.90 to 1.17). Consistently, significant multiplicative and additive interactions were observed between habitual iron supplementation and antihypertensive medication on the risk of incident CKD (p all interaction < 0.05). In conclusion, habitual iron supplementation was related to a higher risk of incident CKD among hypertensive patients, the association might be driven by the use of antihypertensive medication.

Iron Deficiency in Patients with Left Ventricular Assist Devices

Iron deficiency is a common and independent predictor of adverse outcomes in patients with heart failure. The implications of iron deficiency in patients implanted with a left ventricular assist device (LVAD) are less established. This review recaps data on the prevalence, characteristics and impact of Iron deficiency in the LVAD population. A systematic search yielded eight studies involving 517 LVAD patients, with iron deficiency prevalence ranging from 40% to 82%. IV iron repletion was not associated with adverse events and effectively resolved iron deficiency in most patients. However, the effects of iron deficiency and iron repletion on post-implant survival and exercise capacity remain unknown. Although iron deficiency is highly prevalent in LVAD patients, its true prevalence and adverse effects may be misestimated due to inexact diagnostic criteria. Future randomised controlled trials on IV iron treatment in LVAD patients are warranted to clarify the significance of this common comorbidity.

Advances in research on immunocyte iron metabolism, ferroptosis, and their regulatory roles in autoimmune and autoinflammatory diseases

Autoimmune diseases commonly affect various systems, but their etiology and pathogenesis remain unclear. Currently, increasing research has highlighted the role of ferroptosis in immune regulation, with immune cells being a crucial component of the body's immune system. This review provides an overview and discusses the relationship between ferroptosis, programmed cell death in immune cells, and autoimmune diseases. Additionally, it summarizes the role of various key targets of ferroptosis, such as GPX4 and TFR, in immune cell immune responses. Furthermore, the release of multiple molecules, including damage-associated molecular patterns (DAMPs), following cell death by ferroptosis, is examined, as these molecules further influence the differentiation and function of immune cells, thereby affecting the occurrence and progression of autoimmune diseases. Moreover, immune cells secrete immune factors or their metabolites, which also impact the occurrence of ferroptosis in target organs and tissues involved in autoimmune diseases. Iron chelators, chloroquine and its derivatives, antioxidants, chloroquine derivatives, and calreticulin have been demonstrated to be effective in animal studies for certain autoimmune diseases, exerting anti-inflammatory and immunomodulatory effects. Finally, a brief summary and future perspectives on the research of autoimmune diseases are provided, aiming to guide disease treatment strategies.

Bioactivity of Eugenol: A Potential Antibiotic Adjuvant with Minimal Ecotoxicological Impact

Combining commercial antibiotics with adjuvants to lower their minimum inhibitory concentration (MIC) is vital in combating antimicrobial resistance. Evaluating the ecotoxicity of such compounds is crucial due to environmental and health risks. Here, eugenol was assessed as an adjuvant for 7 commercial antibiotics against 14 pathogenic bacteria in vitro, also examining its acute ecotoxicity on various soil and water organisms (microbiota, Vibrio fischeri, Daphnia magna, Eisenia foetida, and Allium cepa). Using microdilution methods, checkerboard assays, and kinetic studies, the MICs for eugenol were determined together with the nature of its combinations with antibiotics against bacteria, some unexposed to eugenol previously. The lethal dose for the non-target organisms was also determined, as well as the Average Well Color Development and the Community-Level Physiological Profiling for soil and water microbiota. Our findings indicate that eugenol significantly reduces MICs by 75 to 98%, which means that it could be a potent adjuvant. Ecotoxicological assessments showed eugenol to be less harmful to water and soil microbiota compared to studied antibiotics. While Vibrio fischeri and Daphnia magna were susceptible, Allium cepa and Eisenia foetida were minimally affected. Given that only 0.1% of eugenol is excreted by humans without metabolism, its environmental risk when used with antibiotics appears minimal.

The crosstalk between mitochondrial quality control and metal-dependent cell death

Mitochondria are the centers of energy and material metabolism, and they also serve as the storage and dispatch hubs of metal ions. Damage to mitochondrial structure and function can cause abnormal levels and distribution of metal ions, leading to cell dysfunction and even death. For a long time, mitochondrial quality control pathways such as mitochondrial dynamics and mitophagy have been considered to inhibit metal-induced cell death. However, with the discovery of new metal-dependent cell death including ferroptosis and cuproptosis, increasing evidence shows that there is a complex relationship between mitochondrial quality control and metal-dependent cell death. This article reviews the latest research results and mechanisms of crosstalk between mitochondrial quality control and metal-dependent cell death in recent years, as well as their involvement in neurodegenerative diseases, tumors and other diseases, in order to provide new ideas for the research and treatment of related diseases.

Excessive dietary iron exposure increases the susceptibility of largemouth bass (Micropterus salmoides) to Aeromonas hydrophila by interfering with immune response, oxidative stress, and intestinal homeostasis

Iron is an essential cofactor in the fundamental metabolic pathways of organisms. Moderate iron intake can enhance animal growth performance, while iron overload increases the risk of pathogen infection. Although the impact of iron on the pathogen-host relationship has been confirmed in higher vertebrates, research in fish is extremely limited. The effects and mechanisms of different levels of iron exposure on the infection of Aeromonas hydrophila in largemouth bass (Micropterus salmoides) remain unclear. In this study, experimental diets were prepared by adding 0, 800, 1600, and 3200 mg/kg of FeSO4∙7H2O to the basal feed, and the impact of a 56-day feeding period on the mortality rate of largemouth bass infected with A. hydrophila was analyzed. Additionally, the relationships between mortality rate and tissue iron content, immune regulation, oxidative stress, iron homeostasis, gut microbiota, and tissue morphology were investigated. The results showed that the survival rate of largemouth bass infected with A. hydrophila decreased with increasing iron exposure levels. Excessive dietary iron intake significantly increased iron deposition in the tissues of largemouth bass, reduced the expression and activity of antioxidant enzymes superoxide dismutase, catalase, and glutathione peroxidase, increased the content of lipid peroxidation product malondialdehyde, and thereby induced oxidative stress. Excessive iron supplementation could influence the immune response of largemouth bass by upregulating the expression of pro-inflammatory cytokines in the intestine and liver, while downregulating the expression of anti-inflammatory cytokines. Additionally, excessive iron intake could also affect iron metabolism by inducing the expression of hepcidin, disrupt intestinal homeostasis by interfering with the composition and function of the gut microbiota, and induce damage in the intestinal and hepatic tissues. These research findings provide a partial theoretical basis for deciphering the molecular mechanisms underlying the influence of excessive iron exposure on the susceptibility of largemouth bass to pathogenic bacteria.

Dose-Responsive Effects of Iron Supplementation on the Gut Microbiota in Middle-Aged Women

Oral iron supplementation is the first-line treatment for addressing iron deficiency, a concern particularly relevant to women who are susceptible to sub-optimal iron levels. Nevertheless, the impact of iron supplementation on the gut microbiota of middle-aged women remains unclear. To investigate the association between iron supplementation and the gut microbiota, healthy females aged 40-65 years (n = 56, BMI = 23 ± 2.6 kg/m2) were retrospectively analyzed from the Alberta's Tomorrow Project. Fecal samples along with various lifestyle, diet, and health questionnaires were obtained. The gut microbiota was assessed by 16S rRNA sequencing. Individuals were matched by age and BMI and classified as either taking no iron supplement, a low-dose iron supplement (6-10 mg iron/day), or high-dose iron (>100 mg/day). Compositional and functional analyses of microbiome data in relation to iron supplementation were investigated using various bioinformatics tools. Results revealed that iron supplementation had a dose-dependent effect on microbial communities. Elevated iron intake (>100 mg) was associated with an augmentation of Proteobacteria and a reduction in various taxa, including Akkermansia, Butyricicoccus, Verrucomicrobia, Ruminococcus, Alistipes, and Faecalibacterium. Metagenomic prediction further suggested the upregulation of iron acquisition and siderophore biosynthesis following high iron intake. In conclusion, adequate iron levels are essential for the overall health and wellbeing of women through their various life stages. Our findings offer insights into the complex relationships between iron supplementation and the gut microbiota in middle-aged women and underscore the significance of iron dosage in maintaining optimal gut health.

A preventative role of nitrate for hypoxia-induced intestinal injury

BACKGROUND

Studying effective interventions for hypoxia-induced injury is crucial, particularly in high-altitude areas. Symptoms stemming from intestinal injuries have a significant impact on the health of individuals transitioning from plains to plateau regions. This research explores the effects and mechanisms of nitrate supplementation in preventing hypoxia-induced intestinal injury.

METHODS

A hypoxia survival mouse model was established using 7% O2 conditions. The intervention with 4 mM sodium nitrate (NaNO3) in drinking water commenced 7 days prior to hypoxia exposure. Weight monitoring, hematoxylin and eosin (HE) staining, transmission electron microscopy (TEM), and intestinal permeability assays were employed for physiological, histological, and functional analyses. Quantitative PCR (qPCR), Western blot, and immunofluorescence were utilized to analyze the levels of tight junction (TJ) proteins and hypoxia-inducible factor 1α (Hif 1α). RNA sequencing (RNA-seq) identified nitrate's target, and chromatin immunoprecipitation (ChIP) verified the transcriptional impact of Hif 1α on TJ proteins. Villin-cre mice infected with AAV9-FLEX-EGFP-Hif 1α were used for mechanism validation.

RESULTS

The results demonstrated that nitrate supplementation significantly alleviated small intestinal epithelial cell necrosis, intestinal permeability, disruption of TJs, and weight loss under hypoxia. Moreover, the nitrate-triggered enhancement of TJs is mediated by Hif 1α nuclear translocation and its subsequent transcriptional function. The effect of nitrate supplementation on TJs was largely attributed to the stimulation of the EGFR/PI3K/AKT/mTOR/Hif 1α signaling pathways.

CONCLUSION

Nitrate serves as a novel approach in preventing hypoxia-induced intestinal injury, acting through Hif 1α activation to promote the transcription of TJ proteins. Furthermore, our study provides new and compelling evidence for the protective effects of nitrate in hypoxic conditions, especially at high altitudes.

The Effect of Oral Iron Supplementation/Fortification on the Gut Microbiota in Infancy: A Systematic Review and Meta-Analysis

(1) Background: Iron is an essential metal for the proper growth and neurodevelopment of infants. To prevent and treat iron deficiency, iron supplementation or fortification is often required. It has been shown, though, that it affects the synthesis of gut microbiota. (2) Methods: This paper is a systematic review and meta-analysis of the effect of oral iron supplementation/fortification on the gut microbiota in infancy. Studies in healthy neonates and infants who received per os iron with existing data on gut microbiota were included. Three databases were searched: PUBMED, Scopus, and Google Scholar. Randomized controlled trials (RCTs) were included. Quality appraisal was assessed using the ROB2Tool. (3) Results: A total of six RCTs met inclusion criteria for a systematic review, and four of them were included in the meta-analysis using both the fixed and random effects methods. Our results showed that there is very good heterogeneity in the iron group (I2 = 62%), and excellent heterogeneity in the non-iron group (I2 = 98%). According to the meta-analysis outcomes, there is a 10.3% (95% CI: -15.0--5.55%) reduction in the bifidobacteria population in the iron group and a -2.96% reduction for the non-iron group. There is a confirmed difference (p = 0.02) in the aggregated outcomes between iron and non-iron supplement, indicative that the bifidobacteria population is reduced when iron supplementation is given (total reduction 6.37%, 95%CI: 10.16-25.8%). (4) Conclusions: The abundance of bifidobacteria decreases when iron supplementation or fortification is given to infants.

Iron deficiency anemia: a critical review on iron absorption, supplementation and its influence on gut microbiota

Iron deficiency anemia (IDA) caused by micronutrient iron deficiency has attracted global attention due to its adverse health effects. The regulation of iron uptake and metabolism is finely controlled by various transporters and hormones in the body. Dietary iron intake and regulation are essential in maintaining human health and iron requirements. The review aims to investigate literature concerning dietary iron intake and systemic regulation. Besides, recent IDA treatment and dietary iron supplementation are discussed. Considering the importance of the gut microbiome, the interaction between bacteria and micronutrient iron in the gut is also a focus of this review. The iron absorption efficiency varies considerably according to iron type and dietary factors. Iron fortification remains the cost-effective strategy, although challenges exist in developing suitable iron fortificants and food vehicles regarding bioavailability and acceptability. Iron deficiency may alter the microbiome structure and promote the growth of pathogenic bacteria in the gut, affecting immune balance and human health.

Iron overload induces colitis by modulating ferroptosis and interfering gut microbiota in mice

BACKGROUND

Iron plays a pivotal role in various physiological processes, including intestinal inflammation, ferroptosis, and the modulation of the gut microbiome. However, the way these factors interact with each other is unclear.

METHODS

Mice models were fed with low, normal and high iron diets to assess their impacts on colitis, ferroptosis and gut microbiota. Untargeted fecal metabolomics analysis, 16S rRNA sequencing, histopathology analysis, real-time quantitative PCR and western blot were performed to analyze the differences in the intestinal inflammatory response and understanding its regulatory mechanisms between low, normal and high iron groups.

RESULTS

The iron overload changed the serum iron, colon iron and fecal iron. In addition, the iron overload induced the colitis, induced the ferroptosis and altered the microbiome composition in the fecal of mice. By using untargeted fecal metabolomics analysis to screen of metabolites in the fecal, we found that different metabolomics profiles in the fecal samples between iron deficiency, normal iron and iron overload groups. The correlation analysis showed that both of iron deficiency and overload were closely related to Dubosiella. The relationship between microbial communities (e.g., Akkermansia, Alistipes, and Dubosiella) and colitis-related parameters was highly significant. Additionally, Alistipes and Bacteroides microbial communities displayed a close association with ferroptosis-related parameters. Iron overload reduced the concentration of metabolites, which exert the anti-inflammatory effects (e.g., (+)-.alpha.-tocopherol) in mice. The nucleotide metabolism, enzyme metabolism and metabolic diseases were decreased and the lipid metabolism was increased in iron deficiency and iron overload groups compared with normal iron group.

CONCLUSION

Iron overload exacerbated colitis in mice by modulating ferroptosis and perturbing the gut microbiota. Iron overload-induced ferroptosis was associated with NRF2/GPX-4 signaling pathway. Specific microbial taxa and their associated metabolites were closely intertwined with both colitis and ferroptosis markers.

The influence of microbiota on ferroptosis in intestinal diseases

Ferroptosis is a distinctive form of iron-dependent necrotic cell death, characterized by excessive lipid peroxidation on cellular membranes and compromised cellular antioxidant defenses. Multiple metabolic pathways, including iron and lipid metabolism, as well as antioxidant systems, contribute to the execution of ferroptosis. The gut microbiota exerts regulatory effects on ferroptosis through its microbial composition, biological functions, and metabolites. Notably, most pathogenic bacteria tend to promote ferroptosis, thereby inducing or exacerbating diseases, while most probiotics have been shown to protect against cell death. Given microbiota colonization in the gut, an intimate association is found between intestinal diseases and microbiota. This review consolidates the essential aspects of ferroptotic processes, emphasizing key molecules and delineating the intricate interplay between gut microbiota and ferroptosis. Moreover, this review underscores the potential utility of gut microbiota modulation in regulating ferroptosis for the treatment of intestinal diseases.

Excess iron intake induced liver injury: The role of gut-liver axis and therapeutic potential

Excessive iron intake is detrimental to human health, especially to the liver, which is the main organ for iron storage. Excessive iron intake can lead to liver injury. The gut-liver axis (GLA) refers to the bidirectional relationship between the gut and its microbiota and the liver, which is a combination of signals generated by dietary, genetic and environmental factors. Excessive iron intake disrupts the GLA at multiple interconnected levels, including the gut microbiota, gut barrier function, and the liver's innate immune system. Excessive iron intake induces gut microbiota dysbiosis, destroys gut barriers, promotes liver exposure to gut microbiota and its derived metabolites, and increases the pro-inflammatory environment of the liver. There is increasing evidence that excess iron intake alters the levels of gut microbiota-derived metabolites such as secondary bile acids (BAs), short-chain fatty acids, indoles, and trimethylamine N-oxide, which play an important role in maintaining homeostasis of the GLA. In addition to iron chelators, antioxidants, and anti-inflammatory agents currently used in iron overload therapy, gut barrier intervention may be a potential target for iron overload therapy. In this paper, we review the relationship between excess iron intake and chronic liver diseases, the regulation of iron homeostasis by the GLA, and focus on the effects of excess iron intake on the GLA. It has been suggested that probiotics, fecal microbiota transfer, farnesoid X receptor agonists, and microRNA may be potential therapeutic targets for iron overload-induced liver injury by protecting gut barrier function.

Polyphenols and polyphenols-based biopolymer materials: Regulating iron absorption and availability from spontaneous to controllable

Iron is an important trace element in the body, and it will seriously affect the body's normal operation if it is taken too much or too little. A large number of patients around the world are suffering from iron disorders. However, there are many problems using drugs to treat iron overload and causing prolonged and unbearable suffering for patients. Controlling iron absorption and utilization through diet is becoming the acceptable, safe and healthy method. At present, many literatures have reported that polyphenols can interact with iron ions and can be expected to chelate iron ions, depending on their types and structures. Besides, polyphenols often interact with other macromolecules in the diet, which may complicate this phenols-Fe behavior and give rise to the necessity of building phenolic based biopolymer materials. The biopolymer materials, constructed by self-assembly (non-covalent) or chemical modification (covalent), show excellent properties such as good permeability, targeting, biocompatibility, and high chelation ability. It is believed that this review can greatly facilitate the development of polyphenols-based biopolymer materials construction for regulating iron and improving the well-being of patients.

Effects of grape seed procyanidins on antioxidant function, barrier function, microbial community, and metabolites of cecum in geese

The gut is the first line of defense for body health and is essential to the overall health of geese. Grape seed procyanidins (GSPs) are proverbial for their antioxidant, anti-inflammatory, and microflora-regulating capabilities. This study aimed to inquire into the influences of dietary GSPs on the intestinal antioxidant function, barrier function, microflora, and metabolites of geese based on 16S rRNA sequencing and metabolomics. In total, 240 twenty-one-day-old Sichuan white geese were randomly divided into 4 groups, each of which was supplied with 1 of 4 diets: basal diet or a basal diet supplemented with 50, 100, or 150 mg/kg GSPs. Diets supplemented with GSPs at different concentrations significantly increased the total antioxidant capacity and superoxide dismutase activity in cecal mucosa (P < 0.001). Dietary supplementation with 50 or 100 mg/kg GSPs significantly increased catalase activity (P < 0.001). The serum diamine oxidase, D-lactic acid, and endotoxin concentrations were decreased by GSP supplementation in the goose diet. Dietary GSP supplementation increased microbial richness and diversity, enhanced the relative abundance of Firmicutes, and decreased that of Bacteroidetes in the cecum. Diets supplemented with 50 or 100 mg/kg GSPs enriched Eubacterium coprostanoligenes and Faecalibacterium. Dietary GSPs substantially raised the acetic and propionic acid concentrations in the cecum. The butyric acid concentration increased when the GSP dosage was 50 or 100 mg/kg. Additionally, dietary GSPs increased the levels of metabolites that belong to lipids and lipid-like molecules or organic acids and derivatives. Dietary GSP supplementation at 100 or 150 mg/kg reduced the levels of spermine (a source of cytotoxic metabolites) and N-acetylputrescine, which promotes in-vivo inflammation. In conclusion, dietary supplementation with GSPs was beneficial to gut health in geese. Dietary GSPs improved antioxidant activity; protected intestinal barrier integrity; increased the abundance and diversity of cecal microflora; promoted the proliferation of some beneficial bacteria; increased the production of acetic, propionic, and butyric acids in the cecum; and downregulated metabolites associated with cytotoxicity and inflammation. These results offer a strategy for promoting intestinal health in farmed geese.

Ferroptosis in Cancer Progression

Ferroptosis is a newly discovered iron-dependent form of regulated cell death driven by phospholipid peroxidation and associated with processes including iron overload, lipid peroxidation, and dysfunction of cellular antioxidant systems. Ferroptosis is found to be closely related to many diseases, including cancer at every stage. Epithelial-mesenchymal transition (EMT) in malignant tumors that originate from epithelia promotes cancer-cell migration, invasion, and metastasis by disrupting cell-cell and cell-cell matrix junctions, cell polarity, etc. Recent studies have shown that ferroptosis appears to share multiple initiators and overlapping pathways with EMT in cancers and identify ferroptosis as a potential predictor of various cancer grades and prognoses. Cancer metastasis involves multiple steps, including local invasion of cancer cells, intravasation, survival in circulation, arrest at a distant organ site, extravasation and adaptation to foreign tissue microenvironments, angiogenesis, and the formation of "premetastatic niche". Numerous studies have revealed that ferroptosis is closely associated with cancer metastasis. From the cellular perspective, ferroptosis has been implicated in the regulation of cancer metastasis. From the molecular perspective, the signaling pathways activated during the two events interweave. This review briefly introduces the mechanisms of ferroptosis and discusses how ferroptosis is involved in cancer progression, including EMT, cancer angiogenesis, invasion, and metastasis.

Bacteria from the gut influence the host micronutrient status

Micronutrient deficiencies or "hidden hunger" remains a serious public health problem in most low- and middle-income countries, with severe consequences for child development. Traditional methods of treatment and prevention, such as supplementation and fortification, have not always proven to be effective and may have undesirable side-effects (i.e., digestive troubles with iron supplementation). Commensal bacteria in the gut may increase bioavailability of specific micronutrients (i.e., minerals), notably by removing anti-nutritional compounds, such as phytates and polyphenols, or by the synthesis of vitamins. Together with the gastrointestinal mucosa, gut microbiota is also the first line of protection against pathogens. It contributes to the reinforcement of the integrity of the intestinal epithelium and to a better absorption of micronutrients. However, its role in micronutrient malnutrition is still poorly understood. Moreover, the bacterial metabolism is also dependent of micronutrients acquired from the gut environment and resident bacteria may compete or collaborate to maintain micronutrient homeostasis. Gut microbiota composition can therefore be modulated by micronutrient availability. This review brings together current knowledge on this two-way relationship between micronutrients and gut microbiota bacteria, with a focus on iron, zinc, vitamin A and folate (vitamin B9), as these deficiencies are public health concerns in a global context.

Programmed death of intestinal epithelial cells in neonatal necrotizing enterocolitis: a mini-review

Necrotizing enterocolitis (NEC) is one of the most fatal diseases in premature infants. Damage to the intestinal epithelial barrier (IEB) is an important event in the development of intestinal inflammation and the evolution of NEC. The intestinal epithelial monolayer formed by the tight arrangement of intestinal epithelial cells (IECs) constitutes the functional IEB between the organism and the extra-intestinal environment. Programmed death and regenerative repair of IECs are important physiological processes to maintain the integrity of IEB function in response to microbial invasion. However, excessive programmed death of IECs leads to increased intestinal permeability and IEB dysfunction. Therefore, one of the most fundamental questions in the field of NEC research is to reveal the pathological death process of IECs, which is essential to clarify the pathogenesis of NEC. This review focuses on the currently known death modes of IECs in NEC mainly including apoptosis, necroptosis, pyroptosis, ferroptosis, and abnormal autophagy. Furthermore, we elaborate on the prospect of targeting IECs death as a treatment for NEC based on exciting animal and clinical studies.

Protocatechuic Acid Alleviates Dextran-Sulfate-Sodium-Induced Ulcerative Colitis in Mice via the Regulation of Intestinal Flora and Ferroptosis

Protocatechuic acid (PCA) is a natural component with multiple biological activities. However, the underlying mechanisms of the effects of PCA on anti-ulcerative colitis (UC) are unclear. A UC mouse model was established by allowing the mice to freely drink a dextran sulfate sodium solution. The mice were administered PCA intragastrically for 7 days. Histological pathology, intestinal flora, and ferroptosis regulators were determined in vivo. Additionally, ferroptotic Caco-2 cells were modeled to investigate the role of PCA in ferroptosis. Our results showed that PCA reduced the levels of the disease activity index, inflammatory factors, and histological damage in UC mice. We also found that the regulation of intestinal flora, especially Bacteroidetes, was one of the potential mechanisms underlying the protective effects of PCA anti-UC. Moreover, PCA downregulated the level of ferroptosis in the colon tissue, as evidenced by a reduced iron overload, decreased glutathione depletion, and a lower level of malondialdehyde production compared with the model group. Similar effects of PCA on ferroptosis were observed in Erastin-treated Caco-2 cells. The results obtained using reactive oxygen species assays and the changes in mitochondrial structure observed via scanning electron microscopy also support these results. Our findings suggested that PCA protected against UC by regulating intestinal flora and ferroptosis.

Oral and intravenous iron treatment alter the gut microbiome differentially in dialysis patients

OBJECTIVE

Chronic kidney disease (CKD) is often complicated by anemia, which seriously affects the quality-of-life and prognosis of patients. These patients usually need iron replacement therapy. Oral iron affects the composition and abundance of intestinal flora by increasing intestinal iron concentration.

METHODS

We undertook an interventional study to investigate the effects of oral versus intravenous iron therapy on the gut microbiota. Oral ferrous succinate tablets (n = 14) or intravenous iron sucrose (n = 14) was administered to anemic maintenance hemodialysis (MHD) patients for 2 months.

RESULTS

Oral and intravenous iron treatments had different effects on gut microbial composition and diversity. After oral iron treatment, the α-diversity was decreased, while at the phylum level, the abundance of Firmicutes was reduced and the abundance of Bacteroides was increased. At the genus level, the abundance of Blautia and Coprococcus was decreased, and the abundance of Bacteroidetes was increased. Oral iron therapy was associated with a higher abundance of Lactobacillus compared with that measured in intravenous iron-treated patients. According to metagenome function prediction analysis, oral iron increased the metabolic processes of phenylalanine, valine, leucine, and isoleucine. These changes may increase uremic toxin levels, thereby increasing the progression of renal disease.

CONCLUSION

Iron therapy affects the diversity and composition of gut flora in MHD patients. Oral iron affects the number of bacteria and increases amino acid metabolism compared with intravenous iron. These results indicate that intravenous iron may be more appropriate for MHD patients.

Hepatic Response to the Interaction Between Thymoquinone and Iron-Dextran: an In Vitro and In Vivo Study

Iron is one of the most important essential elements for cell function. However, iron overload can exert destructive effects on various tissues, especially the liver. The present study was designed to evaluate the effect of thymoquinone (TQ) on hepatotoxicity induced by iron-overload in in vitro and mouse model. After in vitro studies, thirty mice were divided into five groups, six each. Group 1 received normal saline. Group 2 received five doses of iron dextran (i.p; 100 mg/kg, one dose every 2 days). Group 3 received TQ (orally, 2 mg/kg/day). Groups 4 and 5 were administrated iron dextran saline (i.p; 100 mg/kg, one dose every 2 days) following treatment with 0.5 and 2 mg/kg/day of TQ, respectively. Based on the findings of the DPPH experiment, although TQ has significant anti-radical potential, at a safe dose of 15 × 10⁺³ nM, it reduced the IC₅₀ of iron dextran on HepG2 cells by about 25%, in in vitro. Following administration of low-dose TQ (0.5 mg/kg), a significant improvement was observed in serum hepatic enzymes activity and hepatic lipid peroxidation compared to iron dextran. However, administration of TQ-high dose (2 mg/kg) led to decrease antioxidant defense alongside increased serum hepatic enzymes and pathological damages in iron dextran-treated animals. Due to the different efficacy of TQ in treatment groups, it seems that the TQ therapeutic index is low and does not have significant safety in the iron overload status.

Heme oxygenase-1 ameliorates endotoxin-induced acute lung injury by modulating macrophage polarization via inhibiting TXNIP/NLRP3 inflammasome activation

Acute lung injury (ALI) remains a global public health issue without specific and effective treatment options available in the clinic. Alveolar macrophage polarization is involved in the initiation, development and progression of ALI; however, the underlying mechanism remains poorly understood. Heme oxygenase-1 (HO-1) acts as an antioxidant in pulmonary inflammation and has been demonstrated to be linked with the severity and prognosis of ALI. In this study, the therapeutic effects of HO-1 were examined, along with the mechanisms involved, mainly focusing on alveolar macrophage polarization. HO-1 depletion induced higher iNOS and CD86 (M1 phenotype) expression but was significantly decreased in Arg-1 and CD206 (M2 phenotype) expression in BALF alveolar macrophages after equivalent LPS stimulation. We also found that HO-1 deletion distinctly accelerated the expression of inflammasome-associated components NLRP3, ASC and caspase-1 in vivo and in vivo and in vitro. Moreover, on the basis of LPS for MH-S cells, levels of TXNIP, NLRP3, ASC and caspase-1 were increased and HO-1 depletion exacerbated these changes, whereas double depletion of HO-1 and TXNIP partially mitigated these elevations. Also, HO-1 knockdown induced more M1 phenotype and less M2 phenotype compared with LPS alone, whereas double silence of HO-1 and TXNIP partially changed the polarization state. Taken together, we demonstrated that HO-1 could modulate macrophage polarization via TXNIP/NLRP3 signaling pathway, which could be a potential therapeutic target for ALI treatment.

Eugenol eliminates carbapenem-resistant Klebsiella pneumoniae via reactive oxygen species mechanism

Multidrug-resistant (MDR) bacterial infections have gained increasing attention due to the high incidence rates and high mortality, especially for the carbapenem-resistant Klebsiella pneumoniae (CRKP) infection that can cause severe complications (e.g., pneumonia and sepsis) in multiple organs. Therefore, the development of new antibacterial agents against CRKP is imperative. Inspired by natural plant antibacterial agents with broad-spectrum antibacterial properties, the antibacterial/biofilm activity of eugenol (EG) on CRKP and their underlying mechanisms are investigated in our work. It is found that EG exhibits remarkable inhibitory effects on planktonic CRKP in a dose-dependent fashion. Meanwhile, the destruction of membrane integrity induced by the formation of reactive oxygen species (ROS) and glutathione reduction results in the leakage of bacterial cytoplasmic components, including DNA, β-galactosidase, and protein. Moreover, when EG contacts with bacterial biofilm, the whole thickness of the dense biofilm matrix decreases, and the integrity is destroyed. Overall, this work verified that EG could eliminate CRKP via ROS-induced membrane rupture, which offers vital evidence to explain the antibacterial ability of EG against CRKP.

Iron in infectious diseases friend or foe?: The role of gut microbiota

Iron is a trace element involved in metabolic functions for all organisms, from microorganisms to mammalians. Iron deficiency is a prevalent health problem that affects billions of people worldwide, and iron overload could have some hazardous effect. The complex microbial community in the human body, also called microbiota, influences the host immune defence against infections. An imbalance in gut microbiota, dysbiosis, changes the host's susceptibility to infections by regulating the immune system. In recent years, the number of studies on the relationship between infectious diseases and microbiota has increased. Gut microbiota is affected by different parameters, including mode of delivery, hygiene habits, diet, drugs, and plasma iron levels during the lifetime. Gut microbiota may influence iron levels in the body, and iron overload and deficiency can also affect gut microbiota composition. Novel researches on microbiota shed light on the fact that the bidirectional interactions between gut microbiota and iron play a role in the pathogenesis of many diseases, especially infections. A better understanding of these interactions may help us to comprehend the pathogenesis of many infectious and metabolic diseases affecting people worldwide and following the development of more effective preventive and/or therapeutic strategies. In this review, we aimed to present the iron-mediated host-gut microbiota interactions, susceptibility to bacterial infections, and iron-targeted therapy approaches for infections.

A new iron supplement: The chelate of pig skin collagen peptide and Fe2+ can treat iron-deficiency anemia by modulating intestinal flora

Introduction

Iron deficiency anemia (IDA) is one of the most common nutritional diseases encountered all over the world. Nowadays, oral iron supplementation is still the mainstay of IDA treatment.

Methods

In this study, a new iron nutritional supplement named pig skin collagen peptides ferrous chelates (PSCP-Fe) was prepared, and its structure was characterized by the scanning electron microscopy, sykam amino acid analyzer and Fourier transform infrared spectroscopy (FTIR). The anti-IDA activity of PSCP-Fe was evaluated in low-Fe²⁺ diet-induced IDA in rats. 16S amplicon sequencing technology was then used to reveal the mechanism of PSCP-Fe against IDA.

Results

The results of amino acid analysis and FTIR showed that aspartic acid (Asp), arginine (Arg), histidine (His), glutamic acid (Glu), cystine (Cys), and lysine (Lys) residued in PSCP chelated readily with Fe²⁺ through their functional groups. PSCP-Fe treated reversed the hematology-related indexes, such as red blood cells (RBC), hemoglobin (HGB), hematocrit (HCT), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentrate (MCHC), serum ferritin (SF), serum hepcidin (HEPC) and serum transferrin receptor (TFR). And its regulatory action was better than that of FeSO₄. Moreover, PSCP-Fe alleviated the hepatocyte apoptosis and necrosis, Fe²⁺ loss, and injury in IDA rats. In addition, PSCP-Fe could significantly retrace the disturbed profile of gut microbiota in IDA rats (p < 0.05) and significantly up-regulated the relative abundances of nine bacterial genus, including Lactobacillus, Alloprevotella, unclassified_of_Oscillospiraceae, and NK4A214_group (p < 0.05). It could also downgrade the relative abundances of Subdoligranulum and Coriobacteriaceae_UCG-002 (p < 0.05). The results of Spearman's correlation analysis and distance-based redundancy analysis (db-RDA) revealed that Subdoligranulum and Christensenellaceae_R-7_group may be potential microbial markers for effective PSCP-Fe action in the treatment of IDA.

Discussion

Overall, our results elucidate the interactions between gut bacteria and related cytokines and reveal the mechanisms underlying the anti-IDA effect of PSCP-Fe. They will thus provide a theoretical foundation for PSCP-Fe as a new iron nutritional supplement.

Role of ferroptosis inhibitors in the management of diabetes

Ferroptosis, the iron-dependent, lipid peroxide-mediated cell death, has garnered attention due to its critical involvement in crucial physiological and pathological cellular processes. Indeed, several studies have attributed its role in developing a range of disorders, including diabetes. As accumulating evidence further the understanding of ferroptotic mechanisms, the impact this specialized mode of cell death has on diabetic pathogenesis is still unclear. Several in vivo and in vitro studies have highlighted the association of ferroptosis with beta-cell death and insulin resistance, supported by observations of marked alterations in ferroptotic markers in experimental diabetes models. The constant improvement in understanding ferroptosis in diabetes has demonstrated it as a potential therapeutic target in diabetic management. In this regard, ferroptosis inhibitors promise to rescue pancreatic beta-cell function and alleviate diabetes and its complications. This review article elucidates the key ferroptotic pathways that mediate beta-cell death in diabetes, and its complications. In particular, we share our insight into the cross talk between ferroptosis and other hallmark pathogenic mediators such as oxidative and endoplasmic reticulum stress regulators relevant to diabetes progression. Further, we extensively summarize the recent developments on the role of ferroptosis inhibitors and their therapeutic action in alleviating diabetes and its complications.

The Impacts of Iron Overload and Ferroptosis on Intestinal Mucosal Homeostasis and Inflammation

Intestinal homeostasis is maintained through the interplay of the intestinal mucosa, local and systemic immune factors, and the microbial content of the gut. Iron is a trace mineral in most organisms, including humans, which is essential for growth, systemic metabolism and immune response. Paradoxically, excessive iron intake and/or high iron status can be detrimental to iron metabolism in the intestine and lead to iron overload and ferroptosis-programmed cell death mediated by iron-dependent lipid peroxidation within cell membranes, which contributes to several intestinal diseases. In this review, we comprehensively review recent findings on the impacts of iron overload and ferroptosis on intestinal mucosal homeostasis and inflammation and then present the progress of iron overload and ferroptosis-targeting therapy in intestinal diseases. Understanding the involved mechanisms can provide a new understanding of intestinal disease pathogenesis and facilitate advanced preventive and therapeutic strategies for intestinal dysfunction and diseases.

Mesoporous Calcium-Silicate Nanoparticles Loaded with Prussian Blue Promotes Enterococcus Faecalis Ferroptosis-Like Death by Regulating Bacterial Redox Pathway ROS/GSH

Background

Mesoporous calcium-silicate nanoparticles (MCSNs) are advanced biomaterials that have been used to control drug delivery for many years. Ultrasmall Prussian blue nanoparticles (UPBNPs) showed high peroxidase and catalase-like activities. This study evaluated the antibacterial and antibiofilm properties, mechanism and cytotoxicity of UPBNPs-MCSNs composites synthesized by both as precursors.

Methods

UPBNPs-MCSNs were prepared and characterized. The antibacterial effect of UPBNPs-MCSNs was evaluated by the MTT assay and CFU counting method, and their biosafety was tested by CCK8. Then explore the antibacterial mechanism, including TEM observation of bacterial morphology, and detection of bacterial ROS, LPO and GSH levels. The antibiofilm activity of UPBNPs-MCSNs was tested by E. faecalis biofilm model in human roots. The roots were pretreated with materials and cultured with E. faecalis, and the survival of E. faecalis on the root canal wall was observed by SEM and CLSM.

Results

The results showed that UPBNPs-MCSNs had potent antibacterial and antibiofilm activities. They can aggregate on the dentin surface and significantly inhibit E. faecalis adhesion and colonization. Their antibacterial activity is as effective as NaClO and calcium hydroxide (CH), can significantly prolong the time of bacterial colonization than CH, but have lower cytotoxicity to normal cells. We found that UPBNPs-MCSNs trigger a like classic ferroptosis pathway in bacteria. UPBNPs-MCSNs can induce bacteria to produce ROS and LPO, and reduce GSH level. Moreover, we observed that the metal ions chelator and the antioxidant could block their antibacterial activity.

Conclusion

These results reveal that UPBNPS-MCSNs have high antibacterial and antibiofilm, and can mediate the bacterial redox pathway ROS/GSH like the classical pathway of ferroptosis, providing a theoretical basis for them to develop into a safe and effective novel root canal disinfectant.

Tolerability of Oral Supplementation with Microencapsulated Ferric Saccharate Compared to Ferrous Sulphate in Healthy Premenopausal Woman: A Crossover, Randomized, Double-Blind Clinical Trial

A single-center, crossover, randomized, double-blind, and controlled clinical study was conducted to assess the tolerability profile, especially with regard to gastrointestinal complaints, of oral supplementation with AB-Fortis^®, a microencapsulated ferric saccharate (MFS), as compared with conventional ferrous sulphate (FS) in healthy premenopausal women. A dose of 60 mg/day of elemental iron was used. The test products were administered for 14 consecutive days with a washout period of two menstrual episodes and a minimum of one month between the two intervention periods. The subjects completed simple-to-answer questionnaires daily for 14 days during both the intervention and the washout periods, capturing the symptoms associated with oral iron supplementation and overall health aspects. Following product consumption, the incidences of symptoms, numbers of complaints/symptoms, overall intensity, and total days with symptoms were found to be significantly higher for FS consumption as compared to MFS. The better tolerability profile of MFS over FS was further substantiated when both products were compared to a real-life setting (i.e., the washout period). Overall, the administration of both study products was safe with no serious or significant adverse events reported. In summary, the current study shows the better tolerability of the MFS preparation when compared to that of the FS, presenting MFS as a well-tolerated and safe option for improving iron nutrition.

Naringenin protects against iron overload-induced osteoarthritis by suppressing oxidative stress

BACKGROUND

The traditional Chinese medicine Gusuibu, the rhizome of Rhizoma Drynariae, is used to treat rheumatism and fractures. Naringenin (NAR) is an active ingredient in Gusuibu and has significant anti-inflammatory and antioxidant effects. However, the role of naringenin in iron overload-induced osteoarthritis (IOOA) is unknown.

HYPOTHESIS

NAR reduces cartilage damage in IOOA.

METHODS

The effects of NAR on the viability of IOOA chondrocytes and the synthesis ability of type II collagen were evaluated using cell counting kit (CCK8) and toluidine blue assays. To determine the mechanism of action and characteristics of NAR, the intracellular iron ion content, apoptosis rate, and mitochondrial membrane potential (MMP) change, and malondialdehyde (MDA) levels, as well as the degree of reactive oxygen species (ROS) and lipid hydroperoxide (LPO) accumulation in the cells were detected in vitro and verified using western blotting and quantitative real-time PCR (qRT-PCR). To verify the role of NAR in vivo, IOOA mice were established using iron dextran and surgery-induced destabilised medial meniscus. Changes in the articular cartilage and subchondral bone were examined using Safranin O-fast Green staining (S-O), haematoxylin-eosin staining (H&E), and microcomputed tomography (μCT).

RESULTS

In vitro, NAR attenuated the impairment of cell viability, apoptosis, and MMP caused by ferric ammonium citrate and interleukin-1β co-culture, increased the levels of MDA, reduced the expression of matrix metallopeptidase (MMP)3, MMP13, and Bax, and restored the expression of type II collagen (Col II). NAR showed a slight iron accumulation-reducing effect. NAR alleviated the accumulation of ROS and LPO in IOOA chondrocytes and upregulated antioxidant genes nuclear factor E2-related factor 2 (NRF2) and haem oxygenase 1 (HO-1). When ML385, a specific NRF-2 inhibitor, was added, the protective effect of NAR was significantly inhibited. In vivo, NAR reduced synovitis and attenuated cartilage damage and subchondral bone proliferation in IOOA mice.

CONCLUSIONS

NAR can reduce oxidative stress through the NRF2-HO-1 pathway, alleviate cartilage damage under iron overload, and has the potential to treat IOOA.

Polyphenol-Rich Ginger (Zingiber officinale) for Iron Deficiency Anaemia and Other Clinical Entities Associated with Altered Iron Metabolism

Ginger (Zingiber officinale) is rich in natural polyphenols and may potentially complement oral iron therapy in treating and preventing iron deficiency anaemia (IDA). This narrative review explores the benefits of ginger for IDA and other clinical entities associated with altered iron metabolism. Through in vivo, in vitro, and limited human studies, ginger supplementation was shown to enhance iron absorption and thus increase oral iron therapy's efficacy. It also reduces oxidative stress and inflammation and thus protects against excess free iron. Ginger's bioactive polyphenols are prebiotics to the gut microbiota, promoting gut health and reducing the unwanted side effects of iron tablets. Moreover, ginger polyphenols can enhance the effectiveness of erythropoiesis. In the case of iron overload due to comorbidities from chronic inflammatory disorders, ginger can potentially reverse the adverse impacts and restore iron balance. Ginger can also be used to synthesise nanoparticles sustainably to develop newer and more effective oral iron products and functional ingredients for IDA treatment and prevention. Further research is still needed to explore the applications of ginger polyphenols in iron balance and anaemic conditions. Specifically, long-term, well-designed, controlled trials are required to validate the effectiveness of ginger as an adjuvant treatment for IDA.

Emerging roles of ferroptosis in cardiovascular diseases

The mechanism of cardiovascular diseases (CVDs) is complex and threatens human health. Cardiomyocyte death is an important participant in the pathophysiological basis of CVDs. Ferroptosis is a new type of iron-dependent programmed cell death caused by excessive accumulation of iron-dependent lipid peroxides and reactive oxygen species (ROS) and abnormal iron metabolism. Ferroptosis differs from other known cell death pathways, such as apoptosis, necrosis, necroptosis, autophagy and pyroptosis. Several compounds have been shown to induce or inhibit ferroptosis by regulating related key factors or signalling pathways. Recent studies have confirmed that ferroptosis is associated with the development of diverse CVDs and may be a potential therapeutic drug target for CVDs. In this review, we summarize the characteristics and related mechanisms of ferroptosis and focus on its role in CVDs, with the goal of inspiring novel treatment strategies.

The mechanisms of ferroptosis and its role in alzheimer’s disease

Alzheimer’s disease (AD) accounts for two-thirds of all dementia cases, affecting 50 million people worldwide. Only four of the more than 100 AD drugs developed thus far have successfully improved AD symptoms. Furthermore, these improvements are only temporary, as no treatment can stop or reverse AD progression. A growing number of recent studies have demonstrated that iron-dependent programmed cell death, known as ferroptosis, contributes to AD-mediated nerve cell death. The ferroptosis pathways within nerve cells include iron homeostasis regulation, cystine/glutamate (Glu) reverse transporter (system xc⁻), glutathione (GSH)/glutathione peroxidase 4 (GPX4), and lipid peroxidation. In the regulation pathway of AD iron homeostasis, abnormal iron uptake, excretion and storage in nerve cells lead to increased intracellular free iron and Fenton reactions. Furthermore, decreased Glu transporter expression leads to Glu accumulation outside nerve cells, resulting in the inhibition of the system xc⁻ pathway. GSH depletion causes abnormalities in GPX4, leading to excessive accumulation of lipid peroxides. Alterations in these specific pathways and amino acid metabolism eventually lead to ferroptosis. This review explores the connection between AD and the ferroptosis signaling pathways and amino acid metabolism, potentially informing future AD diagnosis and treatment methodologies.

The Dark Side of Iron: The Relationship between Iron, Inflammation and Gut Microbiota in Selected Diseases Associated with Iron Deficiency Anaemia—A Narrative Review

Iron is an indispensable nutrient for life. A lack of it leads to iron deficiency anaemia (IDA), which currently affects about 1.2 billion people worldwide. The primary means of IDA treatment is oral or parenteral iron supplementation. This can be burdened with numerous side effects such as oxidative stress, systemic and local-intestinal inflammation, dysbiosis, carcinogenic processes and gastrointestinal adverse events. Therefore, this review aimed to provide insight into the physiological mechanisms of iron management and investigate the state of knowledge of the relationship between iron supplementation, inflammatory status and changes in gut microbiota milieu in diseases typically complicated with IDA and considered as having an inflammatory background such as in inflammatory bowel disease, colorectal cancer or obesity. Understanding the precise mechanisms critical to iron metabolism and the awareness of serious adverse effects associated with iron supplementation may lead to the provision of better IDA treatment. Well-planned research, specific to each patient category and disease, is needed to find measures and methods to optimise iron treatment and reduce adverse effects.

EPA and DHA confer protection against deoxynivalenol-induced endoplasmic reticulum stress and iron imbalance in IPEC-1 cells

This study assessed the molecular mechanism of EPA or DHA protection against intestinal porcine epithelial cell line 1 (IPEC-1) cell damage induced by deoxynivalenol (DON). The cells were divided into six groups, including the CON group, the EPA group, the DHA group, the DON group, the EPA + DON group and the DHA + DON group. RNA sequencing was used to investigate the potential mechanism, and qRT-PCR was employed to verify the expression of selected genes. Changes in ultrastructure were used to estimate pathological changes and endoplasmic reticulum (ER) injury in IPEC-1 cells. Transferrin receptor 1 (TFR1) was tested by ELISA. Fe²⁺ and malondialdehyde (MDA) contents were estimated by spectrophotometry, and reactive oxygen species (ROS) was assayed by fluorospectrophotometry. RNA sequencing analysis showed that EPA and DHA had a significant effect on the expression of genes involved in ER stress and iron balance during DON-induced cell injury. The results showed that DON increased ER damage, the content of MDA and ROS, the ratio of X-box binding protein 1s (XBP-1s)/X-box binding protein 1u (XBP-1u), the concentration of Fe²⁺ and the activity of TFR1. However, the results also showed that EPA and DHA decreased the ratio of XBP-1s/XBP-1u to relieve DON-induced ER damage of IPEC-1 cells. Moreover, EPA and DHA (especially DHA) reversed the factors related to iron balance. It can be concluded that EPA and DHA reversed IPEC-1 cell damage induced by DON. DHA has the potential to protect IPEC-1 cells from DON-induced iron imbalance by inhibiting ER stress.

Intestinal Absorption Study of a Granular Form of Ferric Pyrophosphate

Iron deficiency is one of the most prevalent nutritional disorders worldwide. The standard treatment involves iron supplementation, but this task is challenging because of poor solubility and organoleptic issues. Moreover, the need to increase iron bioavailability represents a challenge for treating iron-related disorders. In this study, gastroresistance and iron intestinal absorption of an innovative granular formulation composed of ferric pyrophosphate, modified starch and phospholipids branded as Ferro Fosfosoma® was investigated. Gastroresistant properties were studied using standard protocols, and a bioaccessible fraction was obtained by exposing a food supplement to in vitro digestion. This fraction was used for investigating iron absorption in Caco-2 and human follicle-associated intestinal epithelium (FAE) models. Ferro Fosfosoma® showed an improved resistance to gastric digestion and higher intestinal absorption than ferric pyrophosphate salt used as a control in both models. In the FAE model, Ferro Fosfosoma® induces larger iron absorption than in the Caco-2 monolayer, most likely due to the transcytosis ability of M cells. The larger iron absorption in the Ferro Fosfosoma®-treated FAE model corresponds to higher ferritin level, proving physiological iron handling that was once delivered by granular formulation. Finally, the formulation did not induce any alterations in viability and barrier integrity. To conclude, Ferro Fosfosoma® favors iron absorption and ferritin expression, while preserving any adverse effects.

Ferroptosis is involved in PGPS-induced otitis media in C57BL/6 mice

Otitis media (OM) is a common disease that can cause hearing loss in children. Currently, the main clinical treatment for OM is antibiotics, but the overuse of antibiotics might lead to bacterial resistance, which is a worldwide public health challenge. Studying the pathogenesis of OM will help us develop new effective treatments. Ferroptosis is one type of programmed cell death characterized by the occurrence of lipid peroxidation driven by iron ions. Many studies have shown that ferroptosis is associated with infectious diseases. It is presently unclear whether ferroptosis is involved in the pathogenesis of OM. In this study, we explored the relationship between ferroptosis and OM by PGPS-induced OM in C57BL/6 mice and treating the induced OM with ferroptosis inhibitors deferoxamine (DFO), Ferrostatin-1 (Fer-1), and Liperoxstatin-1 (Lip-1). We examined the expression of ferroptosis-related proteins acyl-CoA synthetase long chain family member 4 (ACSL4) and prostaglandin-endoperoxide synthase 2 (Cox2), glutathione peroxidase 4 (GPX4) protein as well as lipid peroxidation markers 4-hydroxynonenal (4-HNE) and malondialdehyde (MDA). The results showed that in PGPS-induced OM model mice, several ferroptosis-related proteins including ACSL4 and Cox2 were up-regulated compared to mice treated with saline. Meanwhile, a ferroptosis-related protein GPX4 was down-regulated upon PGPS treatment. The DFO treatment in PGPS-inoculated mice effectively inhibited the development of OM. The inhibitors treatment caused a significant decrease in the expression of ACSL4, Cox2, 4 HNE, MDA, reduction in free iron. Meanwhile, the ferroptosis inhibitors treatment caused increase in the expression of inflammation-related factors tumor necrosis factor-α (TNF-α) and antioxidant protein GPX4. Our results suggest that there is a crosstalk between ferroptosis signaling pathway and the pathogenesis of OM. Ferroptosis inhibition can alleviate PGPS-induced OM.

The Role of Iron in Staphylococcus aureus Infection and Human Disease: A Metal Tug of War at the Host—Microbe Interface

Iron deficiency anemia can be treated with oral or intravenous Fe supplementation. Such supplementation has considerable effects on the human microbiome, and on opportunistic pathogenic micro-organisms. Molecular understanding of the control and regulation of Fe availability at the host-microbe interface is crucial to interpreting the side effects of Fe supplementation. Here, we provide a concise overview of the regulation of Fe by the opportunistic pathogen Staphylococcus aureus. Ferric uptake regulator (Fur) plays a central role in controlling Fe uptake, utilization and storage in order to maintain a required value. The micro-organism has a strong preference for heme iron as an Fe source, which is enabled by the Iron-regulated surface determinant (Isd) system. The strategies it employs to overcome Fe restriction imposed by the host include: hijacking host proteins, replacing metal cofactors, and replacing functions by non-metal dependent enzymes. We propose that integrated omics approaches, which include metalloproteomics, are necessary to provide a comprehensive understanding of the metal tug of war at the host-microbe interface down to the molecular level.