Increased hepcidin in hemorrhagic plaques correlates with iron-stimulated IL-6/STAT3 pathway activation in macrophages

Natural products and ferroptosis: A novel approach for heart failure management

BACKGROUND

The discovery of ferroptosis has brought a revolutionary breakthrough in heart failure treatment, and natural products, as a significant source of drug discovery, are gradually demonstrating their extraordinary potential in regulating ferroptosis and alleviating heart failure symptoms. In addition to chemically synthesized small molecule compounds, natural products have attracted attention as an important source for discovering compounds that target ferroptosis in treating heart failure.

PURPOSE

Systematically summarize and analyze the research progress on improving heart failure through natural products' modulation of the ferroptosis pathway.

METHODS

By comprehensively searching authoritative databases like PubMed, Web of Science, and China National Knowledge Infrastructure with keywords such as "heart failure", "cardiovascular disease", "heart disease", "ferroptosis", "natural products", "active compounds", "traditional Chinese medicine formulas", "traditional Chinese medicine", and "acupuncture", we aim to systematically review the mechanism of ferroptosis and its link with heart failure. We also want to explore natural small-molecule compounds, traditional Chinese medicine formulas, and acupuncture therapies that can inhibit ferroptosis to improve heart failure.

RESULTS

In this review, we not only trace the evolution of the concept of ferroptosis and clearly distinguish it from other forms of cell death but also establish a comprehensive theoretical framework encompassing core mechanisms such as iron overload and system xc-/GSH/GPX4 imbalance, along with multiple auxiliary pathways. On this basis, we innovatively link ferroptosis with various types of heart failure, covering classic heart failure types and extending our research to pre-heart failure conditions such as arrhythmia and aortic aneurysm, providing new insights for early intervention in heart failure. Importantly, this article systematically integrates multiple strategies of natural products for interfering with ferroptosis, ranging from monomeric compounds and bioactive components to crude extracts and further to traditional Chinese medicine formulae. In addition, non-pharmacological means such as acupuncture are also included.

CONCLUSION

This study fills the gap in the systematic description of the relationship between ferroptosis and heart failure and the therapeutic strategies of natural products, aiming to provide patients with more diverse treatment options and promote the development of the heart failure treatment field.

Disrupting the immune homeostasis: the emerging role of macrophage ferroptosis in autoimmune diseases

Autoimmune diseases are a class of chronic disorders characterized by the aberrant activation of the immune system, where macrophages play a central role in regulating immune responses during disease onset and progression. Ferroptosis, a form of iron-dependent programmed cell death, has recently attracted significant interest due to its involvement in various pathological conditions. In macrophages, ferroptosis not only compromises cell viability but also disrupts immune homeostasis by promoting pro-inflammatory responses and suppressing anti-inflammatory pathways, thereby intensifying inflammation and exacerbating disease severity. While substantial progress has been made in elucidating macrophage ferroptosis in atherosclerosis and oncology, its precise mechanistic role in autoimmune diseases remains largely unexplored. This review systematically summarizes the molecular mechanisms of macrophage ferroptosis and its regulatory effects on immune homeostasis, with particular emphasis on its role in autoimmune diseases, including rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), inflammatory bowel disease (IBD), multiple sclerosis (MS), and systemic sclerosis (SSc). Furthermore, we discuss potential therapeutic targets related to macrophage ferroptosis in these conditions. By integrating current knowledge, this review aims to provide a theoretical framework and novel perspectives for developing innovative therapeutic strategies targeting autoimmune diseases.

Iron metabolism and ferroptosis in health and diseases: The crucial role of mitochondria in metabolically active tissues

Iron is essential in various physiological processes, but its accumulation leads to oxidative stress and cell damage, thus iron homeostasis has to be tightly regulated. Ferroptosis is an iron-dependent non-apoptotic regulated cell death characterized by iron overload and reactive oxygen species accumulation. Mitochondria are organelles playing a crucial role in iron metabolism and involved in ferroptosis. MitoNEET, a protein of mitochondrial outer membrane, is a key element in this process. Ferroptosis, altering iron levels in several metabolically active organs, is linked to several non-communicable diseases. For example, iron overload in the liver leads to hepatic fibrosis and cirrhosis, accelerating non-alcholic fatty liver diseases progression, in the muscle cells contributes to oxidative damage leading to sarcopenia, and in the brain is associated to neurodegeneration. The aim of this review is to investigate the intricate balance of iron regulation focusing on the role of mitochondria and oxidative stress, and analyzing the ferroptosis implications in health and disease.

P. Gingivalis induce macrophage polarization by regulating hepcidin expression in chronic apical periodontitis

INTRODUCTION

Hepcidin, a central regulatory molecule of iron metabolism, is upregulated through the IL-6/STAT3 signaling pathway in inflammatory and infectious states, contributing to the pathogenesis of various diseases. In chronic apical periodontitis (CAP), Porphyromonas gingivalis (P. gingivalis) and its lipopolysaccharides (LPS) activate various immune responses in vivo, contributing to disease progression. This study evaluated the role and mechanism of hepcidin in P. gingivalis-induced bone tissue damage in CAP, focusing on its promotion of macrophage M1 polarization via the IL-6/STAT3 signaling pathway.

METHODS

We analyzed a GSE77459 dataset from the GEO database, containing data from inflammatory and normal dental pulp tissues. RT-qPCR and immunofluorescence staining were used to detect the expression of hepcidin in human CAP tissues and its relationship with macrophages. Mouse bone marrow derived macrophages (BMDMs) were cultured in vitro and stimulated with P. gingivalis LPS. The effects of Stattic on macrophage hepcidin expression, IL-6 expression, STAT3 phosphorylation, and macrophage polarization were detected by ELISA, western blotting, RT-qPCR, and flow cytometry, respectively.

RESULTS

Hepcidin expression in human inflammatory dental pulp tissues was upregulated via the IL-6/STAT3 pathway and correlated with macrophage polarization. Hepcidin-encoding genes were found to be highly expressed and primarily associated with M1 macrophages in CAP tissues. In vitro experiments revealed that P. gingivalis LPS stimulation induced macrophages to express hepcidin through the IL-6/STAT3 pathway and polarize to M1. Additionally, the IL-6/STAT3 pathway inhibitor Stattic suppressed these changes.

CONCLUSIONS

Our study demonstrates that in CAP, macrophages highly express hepcidin, which subsequently alters macrophage metabolism, regulates M1 polarization, and leads to bone tissue destruction.

Targeting ferroptosis in autoimmune diseases: Mechanisms and therapeutic prospects

Ferroptosis is a form of regulated cell death that relies on iron and exhibits unique characteristics, including disrupted iron balance, reduced antioxidant defenses, and abnormal lipid peroxidation. Recent research suggests that ferroptosis is associated with the onset and progression of autoimmune disorders such as systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), inflammatory bowel disease (IBD), and multiple sclerosis (MS). However, the precise effects and molecular mechanisms remain incompletely understood. This article presents an overview of how ferroptosis mechanisms contribute to the development and advancement of autoimmune diseases, as well as the involvement of various immune cells in linking ferroptosis to autoimmune conditions. It also explores potential drug targets within the ferroptosis pathway and recent advancements in therapeutic approaches aimed at preventing and treating autoimmune diseases by targeting ferroptosis. Lastly, the article discusses the challenges and opportunities in utilizing ferroptosis as a potential therapeutic avenue for autoimmune disorders.

The intricate interplay between ferroptosis and efferocytosis in cancer: unraveling novel insights and therapeutic opportunities

The complex interplay between ferroptosis and efferocytosis in cancer has attracted significant interest recently. Efferocytosis, the process of eliminating apoptotic cells, is essential for preserving tissue homeostasis and reducing inflammation. However, dysregulation of efferocytosis can have profound effects on cancer. Apoptotic cells accumulate because of impaired efferocytosis, which triggers chronic inflammation and the release of pro-inflammatory chemicals. Surprisingly, accumulating evidence suggests that dysregulation of ferroptosis- a form of controlled cell death characterized by lipid peroxidation and the buildup iron-dependent reactive oxygen species (ROS)-can influence efferocytic activities within the tumor microenvironment. Dysfunctional iron metabolism and increased lipid peroxidation, are associated with ferroptosis, resulting in inadequate apoptotic cell clearance. Conversely, apoptotic cells can activate ferroptotic pathways, increasing oxidative stress and inducing cell death in cancer cells. This reciprocal interaction emphasizes the complex relationship between efferocytosis and ferroptosis in cancer biology. Understanding and managing the delicate balance between cell clearance and cell death pathways holds significant therapeutic potential in cancer treatment. Targeting the efferocytosis and ferroptosis pathways may offer new opportunities for improving tumor clearance, reducing inflammation, and sensitizing cancer cells to therapeutic interventions. Further research into the interaction between efferocytosis and ferroptosis in cancer will provide valuable insights for the development of novel therapies aimed at restoring tissue homeostasis and improving patient outcomes.

Decoding ferroptosis: Revealing the hidden assassin behind cardiovascular diseases

The discovery of regulatory cell death processes has driven innovation in cardiovascular disease (CVD) therapeutic strategies. Over the past decade, ferroptosis, an iron-dependent form of regulated cell death driven by excessive lipid peroxidation, has been shown to drive the development of multiple CVDs. This review provides insights into the evolution of the concept of ferroptosis, the similarities and differences with traditional modes of programmed cell death (e.g., apoptosis, autophagy, and necrosis), as well as the core regulatory mechanisms of ferroptosis (including cystine/glutamate transporter blockade, imbalance of iron metabolism, and lipid peroxidation). In addition, it provides not only a detailed review of the role of ferroptosis and its therapeutic potential in widely studied CVDs such as coronary atherosclerotic heart disease, myocardial infarction, myocardial ischemia/reperfusion injury, heart failure, cardiomyopathy, and aortic aneurysm but also an overview of the phenomenon and therapeutic perspectives of ferroptosis in lesser-addressed CVDs such as cardiac valvulopathy, pulmonary hypertension, and sickle cell disease. This article aims to integrate this knowledge to provide a comprehensive view of ferroptosis in a wide range of CVDs and to drive innovation and progress in therapeutic strategies in this field.

Direct and macrophage stimulation mediated effects of active, inactive, and cell-free supernatant forms of Akkermansia muciniphila and Faecalibacterium duncaniae on hepcidin gene expression in HepG2 cells

Hepcidin is a crucial regulator of iron homeostasis with protective effects on liver fibrosis. Additionally, gut microbiota can also affect liver fibrosis and iron metabolism. Although the hepatoprotective potential of Akkermansia muciniphila and Faecalibacterium duncaniae, formerly known as F. prausnitzii, has been reported, however, their effects on hepcidin expression remain unknown. We investigated the direct and macrophage stimulation-mediated effects of active, heat-inactivated, and cell-free supernatant (CFS) forms of A. muciniphila and F. duncaniae on hepcidin expression in HepG2 cells by RT-qPCR analysis. Following stimulation of phorbol-12-myristate-13-acetate (PMA) -differentiated THP-1 cells with A. muciniphila and F. duncaniae, IL-6 concentration was assessed via ELISA. Additionally, the resulting supernatant was treated with HepG2 cells to evaluate the effect of macrophage stimulation on hepcidin gene expression. The expression of genes mediating iron absorption and export was also examined in HepG2 and Caco-2 cells via RT-qPCR. All forms of F. duncaniae increased hepcidin expression while active and heat-inactivated/CFS forms of A. muciniphila upregulated and downregulated its expression, respectively. Active, heat-inactivated, and CFS forms of A. muciniphila and F. duncaniae upregulated hepcidin expression, consistent with the elevation of IL-6 released from THP-1-stimulated cells as a macrophage stimulation effect in HepG2 cells. A. muciniphila and F. duncaniae in active, inactive, and CFS forms altered the expression of hepatocyte and intestinal iron-mediated absorption /exporter genes, namely dcytb and dmt1, and fpn in HepG2 and Caco-2 cells, respectively. In conclusion, A. muciniphila and F. duncaniae affect not only directly but also through macrophage stimulation the expression of hepcidin gene in HepG2 cells. These findings underscore the potential of A. muciniphila and F. duncaniae as a potential therapeutic target for liver fibrosis by modulating hepcidin and intestinal and hepatocyte iron metabolism mediated gene expression.

Macrophage Ferroptosis Promotes MMP2/9 Overexpression Induced by Hemin in Hemorrhagic Plaque

BACKGROUND

 Intra-plaque hemorrhage (IPH) leads to rapid plaque progression and instability through upregulation of matrix metalloproteinases (MMPs) and collagen degradation. Hemoglobin-derived hemin during IPH promotes plaque instability. We investigated whether hemin affects MMP overexpression in macrophages and explored the underlying mechanisms.

MATERIAL AND METHODS

 In vivo, hemorrhagic plaque models were established in rabbits and ApoE-/- mice. Ferrostatin-1 was used to inhibit ferroptosis. Plaque size, collagen, and MMP2/9 levels were evaluated using immunohistochemistry, H&E, Sirius Red, and Masson staining. In vitro, mouse peritoneal macrophages were extracted. Western blot and ELISA were used to measure MMP2/9 levels. Bioinformatics analysis investigated the association between MMPs and ferroptosis pathway genes. Macrophage ferroptosis was assessed by evaluating cell viability, lipid reactive oxygen species, mitochondrial ultrastructure, iron content, and COX2 levels after pretreatment with cell death inhibitors. Hemin's impact on ferroptosis and MMP expression was studied using Ferrostatin-1 and SB202190.

RESULTS

 In the rabbit hemorrhagic plaques, hemin deposition and overexpression of MMP2/9 were observed, particularly in macrophage-enriched regions. In vitro, hemin induced ferroptosis and MMP2/9 expression in macrophages. Ferrostatin-1 and SB202190 inhibited hemin-induced MMP2/9 overexpression. Ferrostatin-1 inhibited p38 phosphorylation in macrophages. Ferostatin-1 inhibits macrophage ferroptosis, reduces MMP2/9 levels in plaques, and stabilizes the hemorrhagic plaques.

CONCLUSION

 Our results suggested that hemin-induced macrophage ferroptosis promotes p38 pathway activation and MMP2/9 overexpression, which may play a crucial role in increasing hemorrhagic plaque vulnerability. These findings provide insights into the pathogenesis of hemorrhagic plaques and suggest that targeting macrophage ferroptosis may be a promising strategy for stabilizing vulnerable plaque.

Ferroptosis in ulcerative colitis: Potential mechanisms and promising therapeutic targets

Ulcerative colitis (UC) is a complex immune-mediated chronic inflammatory bowel disease. It is mainly characterized by diffuse inflammation of the colonic and rectal mucosa with barrier function impairment. Identifying new biomarkers for the development of more effective UC therapies remains a pressing task for current research. Ferroptosis is a newly identified form of regulated cell death characterized by iron-dependent lipid peroxidation. As research deepens, ferroptosis has been demonstrated to be involved in the pathological processes of numerous diseases. A growing body of evidence suggests that the pathogenesis of UC is associated with ferroptosis, and the regulation of ferroptosis provides new opportunities for UC treatment. However, the specific mechanisms by which ferroptosis participates in the development of UC remain to be more fully and thoroughly investigated. Therefore, in this review, we focus on the research advances in the mechanism of ferroptosis in recent years and describe the potential role of ferroptosis in the pathogenesis of UC. In addition, we explore the underlying role of the crosslinked pathway between ferroptosis and other mechanisms such as macrophages, neutrophils, autophagy, endoplasmic reticulum stress, and gut microbiota in UC. Finally, we also summarize the potential compounds that may act as ferroptosis inhibitors in UC in the future.

Uncovering the Cardioprotective Potential of Diacerein in Doxorubicin Cardiotoxicity: Mitigating Ferritinophagy-Mediated Ferroptosis via Upregulating NRF2/SLC7A11/GPX4 Axis

Doxorubicin (DOX)-induced cardiotoxicity (DIC) is a life-threatening clinical issue with limited preventive approaches, posing a substantial challenge to cancer survivors. The anthraquinone diacerein (DCN) exhibits significant anti-inflammatory, anti-proliferative, and antioxidant actions. Its beneficial effects on DIC have yet to be clarified. Therefore, this study investigated DCN's cardioprotective potency and its conceivable molecular targets against DIC. Twenty-eight Wister rats were assigned to CON, DOX, DCN-L/DOX, and DCN-H/DOX groups. Serum cardiac damage indices, iron assay, oxidative stress, inflammation, endoplasmic reticulum (ER) stress, apoptosis, ferritinophagy, and ferroptosis-related biomarkers were estimated. Nuclear factor E2-related factor 2 (NRF2) DNA-binding activity and phospho-p53 immunoreactivity were assessed. DCN administration effectively ameliorated DOX-induced cardiac cytomorphological abnormalities. Additionally, DCN profoundly combated the DOX-induced labile iron pool expansion alongside its consequent lethal lipid peroxide overproduction, whereas it counteracted ferritinophagy and enhanced iron storage. Indeed, DCN valuably reinforced the cardiomyocytes' resistance to ferroptosis, mainly by restoring the NRF2/solute carrier family 7 member 11 (SLC7A11)/glutathione peroxidase 4 (GPX4) signaling axis. Furthermore, DCN abrogated the cardiac oxidative damage, inflammatory response, ER stress, and cardiomyocyte apoptosis elicited by DOX. In conclusion, for the first time, our findings validated DCN's cardioprotective potency against DIC based on its antioxidant, anti-inflammatory, anti-ferroptotic, and anti-apoptotic imprint, chiefly mediated by the NRF2/SLC7A11/GPX4 axis. Accordingly, DCN could represent a promising therapeutic avenue for patients under DOX-dependent chemotherapy.

Elevated Hepcidin Expression in Human Carotid Atheroma: Sex-Specific Differences and Associations with Plaque Vulnerability

Hepcidin is upregulated by increased body iron stores and inflammatory cytokines. It is associated with cardiovascular events, arterial stiffness, and increased iron accumulation in human atheroma with hemorrhage. However, it is unknown whether the expression of hepcidin in human carotid plaques is related to plaque severity and whether hepcidin expression differs between men and women. Carotid samples from 58 patients (38 males and 20 females) were immunostained with hepcidin, macrophages, ferritin, and transferrin receptor. Immunocytochemistry of hepcidin was performed on THP-1 macrophages exposed to iron or 7betahydroxycholesterol. Hepcidin expression significantly increases with the progression of human atherosclerotic plaques. Plaques of male patients have significantly higher levels of hepcidin. Expressions of hepcidin are significantly correlated with the accumulation of CD68-positive macrophages and transferrin receptor 1 (TfR1) and apoptosis. In vitro, hepcidin is significantly increased in macrophages exposed to iron and moderately increased following 7-oxysterol treatment. In the cultured cells, suppression of hepcidin protected against macrophage cell death, lysosomal membrane permeabilization, and oxidative stress. Hepcidin may play a crucial role in the development and progression of atherosclerosis. The differential expression of hepcidin in male and female patients and its significant correlations with plaque severity, highlight the potential of hepcidin as a biomarker for risk stratification and therapeutic targeting in atherosclerosis.

Procyanidin improves experimental colitis by regulating macrophage polarization

BACKGROUND

Inflammatory bowel disease (IBD) is a chronic disease with an unclear pathogenesis for which successful treatments are still lacking. It has been reported that procyanidin, a natural antioxidant, relieves colitis, but the specific mechanism is elusive.

PURPOSE

Our present study was designed to investigate the effects of procyanidin on colitis and the regulation of the M1 macrophage phenotype and related signaling pathways.

METHODS

In vivo, we used two classic colitis models to observe the effect of procyanidin on macrophage polarization. In vitro, we further validated the therapeutic effect of procyanidin in the RAW264.7 cell line and peritoneal macrophages.

RESULTS

The current findings provide new evidence that procyanidin ameliorated dextran sulfate sodium (DSS)-induced colitis by preventing the polarization of macrophages to the M1 type and downregulating the levels of proinflammatory factors in cells. We also showed that procyanidin prevented lipopolysaccharide (LPS)-induced elevation of inflammatory cytokines and the activation of proinflammatory macrophages, which was achieved by activating the STAT3 and NF-κB pathways.

CONCLUSIONS

This is the first study to demonstrate that procyanidin alleviates experimental colitis by inhibiting the polarization of proinflammatory macrophages. These data reveal new ideas for the pathogenesis and treatment of inflammatory diseases.

Targeting iron metabolism in osteosarcoma

Osteosarcoma (OS) is the most common primary solid malignant tumour of bone, with rapid progression and a very poor prognosis. Iron is an essential nutrient that makes it an important player in cellular activities due to its inherent ability to exchange electrons, and its metabolic abnormalities are associated with a variety of diseases. The body tightly regulates iron content at the systemic and cellular levels through various mechanisms to prevent iron deficiency and overload from damaging the body. OS cells regulate various mechanisms to increase the intracellular iron concentration to accelerate proliferation, and some studies have revealed the hidden link between iron metabolism and the occurrence and development of OS. This article briefly describes the process of normal iron metabolism, and focuses on the research progress of abnormal iron metabolism in OS from the systemic and cellular levels.

Interaction between macrophages and ferroptosis

Abstract

Ferroptosis, a newly discovered iron-dependent cell death pathway, is characterized by lipid peroxidation and GSH depletion mediated by iron metabolism and is morphologically, biologically and genetically different from other programmed cell deaths. Besides, ferroptosis is usually found accompanied by inflammatory reactions. So far, it has been found participating in the development of many kinds of diseases. Macrophages are a group of immune cells that widely exist in our body for host defense and play an important role in tissue homeostasis by mediating inflammation and regulating iron, lipid and amino acid metabolisms through their unique functions like phagocytosis and efferocytosis, cytokines secretion and ROS production under different polarization. According to these common points in ferroptosis characteristics and macrophages functions, it’s obvious that there must be relationship between macrophages and ferroptosis. Therefore, our review aims at revealing the interaction between macrophages and ferroptosis concerning three metabolisms and integrating the application of certain relationship in curing diseases, mostly cancer. Finally, we also provide inspirations for further studies in therapy for some diseases by targeting certain resident macrophages in distinct tissues to regulate ferroptosis.

Facts

Ferroptosis is considered as a newly discovered form characterized by its nonapoptotic and iron-dependent lipid hydroperoxide, concerning iron, lipid and amino acid metabolisms.

Ferroptosis has been widely found playing a crucial part in various diseases, including hepatic diseases, neurological diseases, cancer, etc.

Macrophages are phagocytic immune cells, widely existing and owning various functions such as phagocytosis and efferocytosis, cytokines secretion and ROS production.

Macrophages are proved to participate in mediating metabolisms and initiating immune reactions to maintain balance in our body.

Recent studies try to treat cancer by altering macrophages’ polarization which damages tumor microenvironment and induces ferroptosis of cancer cells.

Open questions

How do macrophages regulate ferroptosis of other tissue cells specifically?

Can we use the interaction between macrophages and ferroptosis in treating diseases other than cancer?

What can we do to treat diseases related to ferroptosis by targeting macrophages?

Is the use of the relationship between macrophages and ferroptosis more effective than other therapies when treating diseases?

The effect of macrophage polarization on the expression of the oxytocin signalling system in enteric neurons

BACKGROUND

The aim of the current study was to investigate the effect of macrophage polarization on the expression of oxytocin (OT) and the oxytocin receptor (OTR) in enteric neurons.

METHODS

In this study, we used a classic colitis model and D-mannose model to observe the correlation between macrophage polarization and OT signalling system. In order to further demonstrate the effect of macrophages, we examined the expression of OT signalling system after depletion of macrophages.

RESULTS

The data showed that, in vitro, following polarization of macrophages to the M1 type by LPS, the macrophage supernatant contained proinflammatory cytokines (IL-1β, IL-6 and TNF-α) that inhibited the expression of OT and OTR in cultured enteric neurons; following macrophage polarization to the M2 type by IL4, the macrophage supernatant contained anti-inflammatory cytokines (TGF-β) that promoted the expression of OT and OTR in cultured enteric neurons. Furthermore, M1 macrophages decreased the expression of the OT signalling system mainly through STAT3/NF-κB pathways in cultured enteric neurons; M2 macrophages increased the expression of the OT signalling system mainly through activation of Smad2/3 and inhibition of the expression of Peg3 in cultured enteric neurons. In a colitis model, we demonstrated that macrophages were polarized to the M1 type during the inflammatory phase, with significant decreased in the expression of OT and OTR. When macrophages were polarized to the M2 type during the recovery phase, OT and OTR expression increased significantly. In addition, we found that D-mannose increased the expression of OT and OTR through polarization of macrophages to the M2 type.

CONCLUSIONS

This is the first study to demonstrate that macrophage polarization differentially regulates the expression of OT and OTR in enteric neurons.

Ambient fine particulate matter aggravates atherosclerosis in apolipoprotein E knockout mice by iron overload via the hepcidin-ferroportin axis

AIMS

Exposure to fine particulate matter (PM2.5) is correlated to atherosclerosis, but the mechanism remains largely undefined. Iron overload is a significant contributor to atherosclerosis, and iron homeostasis is highly regulated by the hepcidin-ferroportin (FPN) axis. Here we aimed to investigate the association between iron overload and PM2.5-induced atherosclerotic mice.

MAIN METHODS

Apolipoprotein E knockout (ApoE-/-) mice were randomly assigned to filtered air (FA group) or PM2.5 (PM2.5 group) for 3-month inhalation. Daily PM2.5 mass concentrations, serum levels of ferritin, iron, pro-atherosclerotic cytokines and lipid profiles, atherosclerotic lesion areas, hepcidin, FPN and iron depositions in atherosclerotic lesions, hepcidin, FPN mRNA and protein expressions in the aorta were detected, respectively.

KEY FINDINGS

The daily average concentration of atmospheric PM2.5 was 68.2 ± 21.8 μg/m3. Serum levels of ferritin, iron, VEGF, MCP-1, IL-6, TNF-α, TC and LDL-C, atherosclerotic lesion areas, hepcidin and iron depositions in atherosclerotic lesions, hepcidin mRNA and protein expressions in the PM2.5 group were observably higher than those in the FA group. Nevertheless, FPN deposition in atherosclerotic lesions, FPN mRNA and protein expressions in the aorta of the PM2.5 group were markedly lower than those of the FA group.

SIGNIFICANCE

PM2.5 inhalation could exacerbate the formation and development of atherosclerosis in ApoE-/- mice, the potential mechanisms may be partly associated with iron overload via the hepcidin-FPN axis, as well as iron-triggered systemic inflammation and hyperlipidemia.

The tandem stenosis mouse model: Towards understanding, imaging, and preventing atherosclerotic plaque instability and rupture

The rupture of unstable atherosclerotic plaques is the major cause of cardiovascular mortality and morbidity. Despite significant limitations in our understanding and ability to identify unstable plaque pathology and prevent plaque rupture, most atherosclerosis research utilises preclinical animal models exhibiting stable atherosclerosis. Here, we introduce the tandem stenosis (TS) mouse model that reflects plaque instability and rupture, as seen in patients. The TS model involves dual ligation of the right carotid artery, leading to locally predefined unstable atherosclerosis in hypercholesterolaemic mice. It exhibits key characteristics of human unstable plaques, including plaque rupture, luminal thrombosis, intraplaque haemorrhage, large necrotic cores, thin or ruptured fibrous caps and extensive immune cell accumulation. Altogether, the TS model represents an ideal preclinical tool for improving our understanding of human plaque instability and rupture, for the development of imaging technologies to identify unstable plaques, and for the development and testing of plaque-stabilising treatments for the prevention of atherosclerotic plaque rupture.

[Effect of Qingshen Granules on inflammation/hepcidin axis and iron metabolism in patients with renal anemia: a single-center, randomized controlled trial]

OBJECTIVE

To evaluate the therapeutic effect of Qingshen Granules on renal anemia in patients with damp-heat syndrome and explore the mechanisms in light of inflammation/hepcidin axis and iron metabolism.

METHODS

Sixty patients with renal anemia and dampness-heat syndrome were randomized into control group (n=30) and treatment group (n=30). All the patients were given routine treatment, and the patients in the treatment group received additional treatment with Qingshen Granules (3 times a day). After 12 weeks of treatments, the patients were examined for changes in the integral value of TCM syndrome, serum creatinine (Scr), glomerular filtration rate (eGFR), hemoglobin (HGB), hematocrit (HCT), red blood cell (RBC) count, interleukin-6 (IL-6), hypersensitive C-reactive protein (hs-CRP), ferritin, growth differentiation factor-15 (GDF-15), serum iron (SI), total iron binding capacity (TIBC), transferrin saturation (TAST), soluble transferrin receptor (sTfR) and ferritin levels.

RESULTS

After the treatment, the scores of TCM syndrome were significantly improved in the treatment group and were better than those in the control group (P=0.000). Scr and eGFR were improved in both groups after the treatment. The levels of HGB, HCT and RBC were all improved in the two groups after treatment, and the improvements were more obvious in the treatment group (P=0.002, 0.002, and 0.017, respectively). The levels of IL-6, hs-CRP, hepcidine and GDF-15 were all lowered in the two groups after the treatment, and they were all significantly lower in the treatment group than in the control group (all P=0.000). The treatments increased the levels of SI and TAST in both of the groups, and compared with those in control group, the levels of TIBC, sTfR and ferritin were significantly lowered in the treatment group after the 12-week treatment (P=0.000).

CONCLUSIONS

Qingshen granules can effectively improve renal anemia in patients with damp-heat syndrome possibly by improving iron metabolism through alleviation of inflammation and reduction of hepcidine level.