The magnitude of the plasma hepcidin response to oral iron supplements depends on the iron dosage.

BACKGROUND: Iron deficiency without anaemia is a common health problem, especially in young menstruating women. The efficacy of the usually recommended oral iron supplementation is limited due to increased plasma hepcidin concentration, which reduces iron absorption and leads to side effects such as intestinal irritation. This observation raises the question of how low-dose iron therapy may affect plasma hepcidin levels and whether oral iron intake dose-dependently affects plasma hepcidin production. METHODS: Fifteen non-anaemic women with iron deficiency (serum ferritin ≤30 ng/ml) received a single dose of 0, 6, 30, or 60 mg of elemental oral iron as ferrous sulfate on different days. Plasma hepcidin was measured before and seven hours after each dose. RESULTS: Subjects had an average age of 23 (standard deviation = 3.0) years and serum ferritin of 24 ng/ml (interquartile range = 16-27). The highest mean change in plasma hepcidin levels was measured after ingesting 60 mg of iron, increasing from 2.1 ng/ml (interquartile range = 1.6-2.9) to 4.1 ng/ml (interquartile range = 2.5-6.9; p < 0.001). Iron had a significant dose-dependent effect on the absolute change in plasma hepcidin (p = 0.008), where lower iron dose supplementation resulted in lower plasma hepcidin levels. Serum ferritin levels were significantly correlated with fasting plasma hepcidin levels (R2 = 0.504, p = 0.003) and the change in plasma hepcidin concentration after iron intake (R2 = 0.529, p = 0.002). CONCLUSION: We found a dose-dependent effect of iron supplementation on plasma hepcidin levels. Lower iron dosage results in a smaller increase in hepcidin and might thus lead to more efficient intestinal iron absorption and fewer side effects. The effectiveness and side effects of low-dose iron treatment in women with iron deficiency should be further investigated. This study was registered at the Swiss National Clinical Trials Portal (2021-00312) and ClinicalTrials.gov (NCT04735848).

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

BACKGROUND: Iron deficiency (ID) is a frequent comorbidity in patients with acute (AHF) and chronic heart failure (CHF) associated with morbidity and death. We aimed to better characterize iron homeostasis in patients with heart failure applying different biomarkers and to evaluate the accuracy of current ID definition by the European Society of Cardiology/American College of Cardiology/American Heart Association to indicate tissue iron availability and demand. METHODS AND RESULTS: We performed a retrospective cohort study investigating 277 patients with AHF and 476 patients with CHF between February 2021 and May 2022. Patients with AHF had more advanced ID than patients with CHF, reflected by increased soluble transferrin receptor and soluble transferrin receptor-ferritin index, and lower ferritin, serum iron, transferrin saturation, hepcidin, and reticulocyte hemoglobin. Decreased iron availability or increased tissue iron demand, reflected by increased soluble transferrin receptor-ferritin index and decreased reticulocyte hemoglobin, was found in 84.1% (AHF) and 28.0% (CHF) with absolute ID and in 50.0% (AHF) and 10.5% (CHF) with combined ID according to the current European Society of Cardiology/American College of Cardiology/American Heart Association-based ID definition. Low hepcidin expression as an indicator of systemic ID was found in 91.1% (AHF) and 80.4% (CHF) of patients with absolute ID and in 32.3% (AHF) and 18.8% (CHF) of patients with combined ID. ID definitions with higher specificity reduce the need for iron supplementation by 25.5% in patients with AHF and by 65.6% in patients with CHF. CONCLUSIONS: Our results suggest that the current European Society of Cardiology/American College of Cardiology/American Heart Association-based ID definition might overestimate true ID, particularly in CHF. More stringent thresholds for ID could more accurately identify patients with heart failure with reduced tissue iron availability who benefit from intravenous iron supplementation.

Regulation of iron metabolism in HEC-1A endometrium cells by macrophage-derived factors and fractalkine.

Macrophages in the endometrium promote receptivity and implantation by secreting proinflammatory cytokines and other factors like fractalkine (FKN). Macrophages are closely linked to regulating iron homeostasis and can modulate iron availability in the tissue microenvironment. It has been revealed that the iron metabolism of the mother is crucial in fertility. Iron metabolism is strictly controlled by hepcidin, the principal iron regulatory protein. The inflammatory cytokines can modulate hepcidin synthesis and, therefore, the iron metabolism of the endometrium. It was proven recently that FKN, a unique chemokine, is implicated in maternal-fetal communication and may contribute to endometrial receptivity and implantation. In the present study, we investigated the effect of activated THP-1 macrophages and FKN on the iron metabolism of the HEC-1A endometrial cells. We established a noncontact coculture with or without recombinant human FKN supplementation to study the impact of the macrophage-derived factors and FKN on the regulation of hepcidin synthesis and iron release and storage of endometrial cells. Based on our findings, the conditioned medium of the activated macrophages could modify hepcidin synthesis via the nuclear factor kappa-light-chain-enhancer of activated B cells, the signal transducer and activator of transcription 3, and the transferrin receptor 2/bone morphogenetic protein 6/suppressor of mothers against decapentaplegic 1/5/8 signaling pathways, and FKN could alter this effect on the endometrial cells. It was also revealed that the conditioned macrophage medium and FKN modulated the iron release and storage of HEC-1A cells. FKN signaling may be involved in the management of iron trafficking of the endometrium by the regulation of hepcidin. It can contribute to the iron supply for fetal development at the early stage of the pregnancy.

The association of TMPRSS6 gene polymorphism with iron status in Egyptian children (a pilot study).

Several studies have shown association of single nucleotide polymorphisms (SNPs) of hepcidin regulatory pathways genes with impaired iron status. The most common is in the TMPRSS6 gene. In Africa, very few studies have been reported. We aimed to investigate the correlation between the common SNPs in the transmembrane protease, serine 6 (TMPRSS6) gene and iron indicators in a sample of Egyptian children for identifying the suitable candidate for iron supplementation.Patients and methods One hundred and sixty children aged 5-13 years were included & classified into iron deficient, iron deficient anemia and normal healthy controls. All were subjected to assessment of serum iron, serum ferritin, total iron binding capacity, complete blood count, reticulocyte count, serum soluble transferrin receptor and serum hepcidin. Molecular study of TMPRSS6 genotyping polymorphisms (rs4820268, rs855791 and rs11704654) were also evaluated.Results There was an association of iron deficiency with AG of rs855791 SNP, (P = 0.01). The minor allele frequency for included children were 0.43, 0.45 & 0.17 for rs4820268, rs855791 & rs11704654 respectively. Genotype GG of rs4820268 expressed the highest hepcidin gene expression fold, the lowest serum ferroportin & iron store compared to AA and AG genotypes (p = 0.05, p = 0.05, p = 0.03 respectively). GG of rs855791 had lower serum ferritin than AA (p = 0.04), lowest iron store & highest serum hepcidin compared to AA and AG genotypes (p = 0.04, p = 0.01 respectively). Children having CC of rs11704654 had lower level of hemoglobin, serum ferritin and serum hepcidin compared with CT genotype (p = 0.01, p = 0.01, p = 0.02) respectively.Conclusion Possible contribution of SNPs (rs855791, rs4820268 and rs11704654) to low iron status.

Developmental exposure to cobalt chloride affected mouse testis via altered iron metabolism in adulthood.

INRODUCTION: Cobalt (Co) is known to interfere with iron (Fe) metabolism that is essential for differentiating male germ cells. Our aim was to study the effect of developmental chronic cobalt exposure on mouse testis through changes in iron homeostasis in adulthood. METHODS: Pregnant ICR mice were exposed to 75 mg (low dose) or 125 mg (high dose)/kg b.w. cobalt chloride (CoCl2) with drinking water for 3 days before delivery and treatment continued until postnatal day 90 of the pups. Age-matched control animals obtained regular tap water. Testes of control and Co-treated mice were processed for immunohistochemistry and inductively coupled plasma mass spectrometry. Sperm count was performed. RESULTS: Chronic CoCl2 administration resulted in significant dose-dependent Co accumulation in sera and testes of the exposed mice. Fe content also showed a significant increase in sera and testes compared to the untreated controls. Surprisingly, testes of low dose-treated mice had ∼ 2.7-fold higher Fe content compared to those exposed to the high dose. A significant dose-dependent reduction in relative testis weight by 18.8% and by 37.7% was found after treatment with low and high dose CoCl2, respectively was found. Our study demonstrated that developmental chronic exposure to CoCl2 affected cellular composition of the testis manifested by germ cell loss and low sperm count, accompanied by altered androgen response in Sertoli cells (loss of stage-specific expression of androgen receptor). A possible mechanism involved is iron accumulation in the testis that was associated with altered ferroportin-hepcidin localization in seminiferous tubules depleted in germ cells. As a protective mechanism for germ cells in condition of iron excess, ferroportin was distributed in Sertoli cells around elongating spermatids. Similar changes in expression of transferrin receptor 1 (TfR1) and divalent metal transporter 1 (DMT1) implied that both factors of testicular Fe homeostasis are closely related. Outside the seminiferous tubules, Leydig cells localized ferroportin, hepcidin, DMT1 and TfR1 thus they could be considered as a main site for iron metabolism. CONCLUSION: Our data suggest that Co exerts its effects on the testis by indirect mechanism possibly through alteration in Fe homeostasis.

HIF-PHD inhibitor desidustat ameliorates iron deficiency anemia.

Iron deficiency anemia is caused by many pathological conditions like chronic kidney disease (CKD), inflammation, malnutrition and gastrointestinal abnormality. Current treatments that are erythropoiesis stimulating agents (ESAs) and iron supplementation are inadequate and often lead to tolerance and/or toxicity. Desidustat, a prolyl hydroxylase (PHD) inhibitor, is clinically used for the treatment of anemia with CKD. In this study, we investigated the effect of desidustat on iron deficiency anemia (IDA). IDA was induced in C57BL6/J mice by iron deficient diet feeding. These mice were then treated with desidustat (15 mg/kg, PO) and FeSO4 (20 mg/kg) for five weeks and effect of the treatment on hematology, iron homeostasis, and bone marrow histology was observed. Effect of desidustat on iron metabolism in inflammation (LPS)-induced iron deficiency was also assessed. Both, Desidustat and FeSO4, increased MCV (mean corpuscular volume), MCH (mean corpuscular hemoglobin), hemoglobin, and HCT (hematocrit) in blood and increased iron in serum, liver, and spleen. Desidustat increased MCHC (mean corpuscular hemoglobin concentration) while FeSO4 treatment did not alter it. FeSO4 treatment significantly increased iron deposition in liver, and spleen, while desidustat increased iron in circulation and demonstrated efficient iron utilization. Desidustat increased iron absorption, serum iron and decreased hepcidin without altering tissue iron, while FeSO4 increased serum and tissue iron by increasing hepcidin in LPS-induced iron deficiency. Desidustat increased erythroid population, especially iron-dependent polychromatic normoblasts and orthochromatic normoblasts, while FeSO4 did not improve cell architecture. PHD inhibition by desidustat improved iron utilization in iron deficiency anemia, by efficient erythropoiesis.

Nutritional Modulation of Hepcidin in the Treatment of Various Anemic States.

Twenty years after its discovery, hepcidin is still considered the main regulator of iron homeostasis in humans. The increase in hepcidin expression drastically blocks the flow of iron, which can come from one's diet, from iron stores, and from erythrophagocytosis. Many anemic conditions are caused by non-physiologic increases in hepcidin. The sequestration of iron in the intestine and in other tissues poses worrying premises in view of discoveries about the mechanisms of ferroptosis. The nutritional treatment of these anemic states cannot ignore the nutritional modulation of hepcidin, in addition to the bioavailability of iron. This work aims to describe and summarize the few findings about the role of hepcidin in anemic diseases and ferroptosis, as well as the modulation of hepcidin levels by diet and nutrients.

Djulis Hull Enhances the Efficacy of Ferric Citrate Supplementation via Restoring Normal Iron Efflux through the IL-6-Hepcidin-Ferroportin Pathway in High-Fat-Diet-Induced Obese Rats.

Obesity-related functional iron disorder remains a major nutritional challenge. We evaluated the effects of djulis hull (DH) on iron metabolism in 50% high-fat-diet-induced obese rats supplemented with ferric citrate (2 g iron/kg diet) for 12 weeks. DH supplementation (5, 10, 15% dry weight/kg diet) significantly increased serum and hepatic iron but decreased appetite hormones, body weight, hepcidin, and liver inflammation (all p < 0.05). The Spearman correlation showed that appetite hormones were negatively associated with iron but positively correlated with liver hepcidin (all p < 0.05). A Western blot analysis showed that DH significantly downregulated hepatic hepcidin through the IL-6-JAK-STAT3 and enhanced ferroportin (Fpn) via the Keap1-Nrf2 and PHD2-HIF-2α. An in vitro study revealed that major bioactive compounds of DH, hexacosanol, and squalene suppressed LPS-induced IL-6 and hepcidin but enhanced Fpn expression in activated THP-1 cells. In conclusion, DH may exert nutraceutical properties for the treatment of functional iron disorder and restoration of iron efflux may have beneficial effects on weight control.

Differences in bone microarchitecture between genetic and secondary iron-overload mouse models suggest a role for hepcidin deficiency in iron-related osteoporosis.

Iron overload is one of the secondary osteoporosis etiologies. Cellular and molecular mechanisms involved in iron-related osteoporosis are not fully understood. AIM: The aim of the study was to investigate the respective roles of iron excess and hepcidin, the systemic iron regulator, in the development of iron-related osteoporosis. MATERIAL AND METHODS: We used mice models with genetic iron overload (GIO) related to hepcidin deficiency (Hfe-/- and Bmp6-/- ) and secondary iron overload (SIO) exhibiting a hepcidin increase secondary to iron excess. Iron concentration and transferrin saturation levels were evaluated in serum and hepatic, spleen, and bone iron concentrations were assessed by ICP-MS and Perl's staining. Gene expression was evaluated by quantitative RT-PCR. Bone micro-architecture was evaluated by micro-CT. The osteoblastic MC3T3 murine cells that are able to mineralize were exposed to iron and/or hepcidin. RESULTS: Despite an increase of bone iron concentration in all overloaded mice models, bone volume/total volume (BV/TV) and trabecular thickness (Tb.Th) only decreased significantly in GIO, at 12 months for Hfe-/- and from 6 months for Bmp6-/- . Alterations in bone microarchitecture in the Bmp6-/- model were positively correlated with hepcidin levels (BV/TV (ρ = +.481, p < .05) and Tb.Th (ρ = +.690, p < .05). Iron deposits were detected in the bone trabeculae of Hfe-/- and Bmp6-/- mice, while iron deposits were mainly visible in bone marrow macrophages in secondary iron overload. In cell cultures, ferric ammonium citrate exposure abolished the mineralization process for concentrations above 5 µM, with a parallel decrease in osteocalcin, collagen 1, and alkaline phosphatase mRNA levels. Hepcidin supplementation of cells had a rescue effect on the collagen 1 and alkaline phosphatase expression level decrease. CONCLUSION: Together, these data suggest that iron in excess alone is not sufficient to induce osteoporosis and that low hepcidin levels also contribute to the development of osteoporosis.

Evaluation of iron metabolism in hospitalized COVID-19 patients.

BACKGROUND: Iron metabolism dysregulation may play a role in organ failure observed in Coronavirus disease 2019 (COVID-19). This study aimed to explore the whole iron metabolism in hospitalized COVID-19 patients and evaluate the impact of tocilizumab. METHODS: We performed an observational multicentric cohort study, including patients with PCR-provenCOVID-19 from the intensive care unit (ICU) (n = 66) and medical ward (n = 38). We measured serum interleukin-6 (IL-6), ferritin, glycosylated ferritin (GF), transferrin, iron, and hepcidin. The primary outcome was death. RESULTS: Among the 104 patients, we observed decreased median GF percentage (35 %; IQ 23-51.5), low iron concentration (7.5 µmol/L; IQ 4-14), normal but low transferrin saturation (TSAT; 21%; IQ 11-33) and increased median hepcidin concentration (58.7 ng/mL; IQ 20.1-92.1). IL-6, ferritin, and GF were independently and significantly associated with death (p = 0.026, p = 0.023, and p = 0.009, respectively). Surprisingly, we observed a decorrelation between hepcidin and IL-6 concentrations in some patients. These findings were amplified in tocilizumab-treated patients. CONCLUSION: Iron metabolism is profoundly modified in COVID-19. The pattern we observed presents differences with a typical inflammation profile. We observed uncoupled IL-6/hepcidin levels in some patients. The benefit of additive iron chelation therapy should be questionable in this setting.

Low Serum Hepcidin Levels in Patients with Ulcerative Colitis - Implications for Treatment of Co-existent Iron-Deficiency Anemia.

Ulcerative colitis (UC) is often associated with anemia. Hepcidin, the central regulator of iron homeostasis, is known to be induced by inflammation and suppressed by anemia. It is not clear how hepcidin is affected in those with UC, when both inflammation and anemia may co-exist.Such knowledge may hold implications for treatment. Hematological and iron-related parameters, C-reactive protein (CRP), growth differentiation factor 15 (GDF-15) and erythroferrone (ERFE) (erythroid regulators of hepcidin) levels were estimated in blood from those with UC and in control subjects. Values for hematological and iron-related parameters showed evidence of iron-deficiency and resultant anemia, in patients with UC. The presence of UC was significantly associated with inflammation. Serum levels of ERFE, but not of GDF-15, were significantly higher in patients with UC than in control patients, while hepcidin levels were significantly lower. Serum hepcidin concentrations in patients with UC correlated positively with serum iron, ferritin and GDF-15, and negatively with serum ERFE. The iron status and serum hepcidin levels in UC patients with co-existent anemia were significantly lower and serum ERFE values significantly higher than in those with UC without anemia. The effect of anemia on hepcidin predominated over that of inflammation in patients with UC, resulting in suppressed hepcidin levels. This effect is possibly mediated through erythroferrone. We suggest that a serum hepcidin-guided approach may be useful to guide use of oral iron supplements to treat co-existent iron-deficiency anemia in patients with UC and other chronic inflammatory diseases.

Pre-emptive iron supplementation prevents myocardial iron deficiency and attenuates adverse remodelling after myocardial infarction.

AIMS: Heart failure (HF) after myocardial infarction (MI) is a major cause of morbidity and mortality. We sought to investigate the functional importance of cardiac iron status after MI and the potential of pre-emptive iron supplementation in preventing cardiac iron deficiency (ID) and attenuating left ventricular (LV) remodelling. METHODS AND RESULTS: MI was induced in C57BL/6J male mice by left anterior descending coronary artery ligation. Cardiac iron status in the non-infarcted LV myocardium was dynamically regulated after MI: non-haem iron and ferritin increased at 4 weeks but decreased at 24 weeks after MI. Cardiac ID at 24 weeks was associated with reduced expression of iron-dependent electron transport chain (ETC) Complex I compared with sham-operated mice. Hepcidin expression in the non-infarcted LV myocardium was elevated at 4 weeks and suppressed at 24 weeks. Hepcidin suppression at 24 weeks was accompanied by more abundant expression of membrane-localized ferroportin, the iron exporter, in the non-infarcted LV myocardium. Notably, similarly dysregulated iron homeostasis was observed in LV myocardium from failing human hearts, which displayed lower iron content, reduced hepcidin expression, and increased membrane-bound ferroportin. Injecting ferric carboxymaltose (15 µg/g body weight) intravenously at 12, 16, and 20 weeks after MI preserved cardiac iron content and attenuated LV remodelling and dysfunction at 24 weeks compared with saline-injected mice. CONCLUSION: We demonstrate, for the first time, that dynamic changes in cardiac iron status after MI are associated with local hepcidin suppression, leading to cardiac ID long term after MI. Pre-emptive iron supplementation maintained cardiac iron content and attenuated adverse remodelling after MI. Our results identify the spontaneous development of cardiac ID as a novel disease mechanism and therapeutic target in post-infarction LV remodelling and HF.

Characterization of hepcidin gene and protection of recombinant hepcidin supplemented in feed against Aeromonas hydrophila infection in Yellow River carp (Cyprinus carpio haematopterus).

Hepcidin is a small peptide of defensins with antibacterial activity, and plays an important role in innate immunity against pathogenic microorganisms, which can also participate in the regulation of iron metabolism. The hepcidin gene in Yellow River carp (Cyprinus carpio haematopterus) (CcHep) was cloned and identified. The total length of CcHep cDNA was 480 bp, containing an open reading frame (ORF) that encoded 91 amino acids (aa), which contained a 24-aa signal peptide, a 42-aa propeptide, and a 25-aa mature peptide. The mature peptide had a typical RX (K/R) R motif and eight conserved cysteine residues forming four pairs of disulfide bonds. Homology and phylogenetic tree analysis showed that CcHep had the closest relationship with that of crucian carp. The expression levels of hepcidin mRNA in healthy and Aeromonas hydrophila stimulated fish were measured by real-time fluorescence quantitative PCR. The results showed that CcHep mRNA was expressed in different tissues of healthy fish with the highest relative expression level in liver, followed by kidney and intestine, and the lowest expression level was observed in heart. The hepcidin gene was extremely significantly up-regulated in head kidney, intestine, liver, skin, spleen, and gill at 6 h and 12 h after A. hydrophila infection. Furthermore, the immunoregulation effect of dietary recombinant protein was evaluated. The recombinant hepcidin protein (rCcHep) was successfully expressed by Pichia pastoris X-33 and showed strong antibacterial activity against A. hydrophila, Escherichia coli, Vibrio anguillarum and Bacillus subtilis in vitro. In order to evaluate the preventive effect of rCcHep, fish were fed with basal diet or diet supplemented with different doses of rCcHep, and then challenged with A. hydrophila. The results showed that immune genes were up-regulated to varying degrees, and feed additive groups exhibited a significantly improved up-regulation expressions of Lysozyme, Toll-like receptor 5 (TLR 5), Major histocompatibility complex classⅡ (MHCⅡ), while inhibited up-regulation expressions of Interleukin 1ß (IL-1ß), Interleukin 8 (IL-8), and Tumor necrosis factor α (TNF-α) in liver and spleen compared to the control. Meanwhile, the relative immune protection rate in 120 mg/kg feed additive group was 28%, and the bacterial clearance rate in tissues of this group was higher than that of the control. Collectively, these results indicated that rCcHep had antibacterial activity and showed an immune protection effect against A. hydrophila, and could be considered as a dietary supplement to apply in aquaculture.

Antibacterial and immunoregulatory activity of an antimicrobial peptide hepcidin in loach (Misgurnus anguillicaudatus).

Antimicrobial peptides (AMPs) are members of humoral immunity and particpate in resisting microbial invasion. In this study, an AMP gene hepcidin was obtained from the oriental loach Misgurnus anguillicaudatus and named Ma-Hep. This Ma-Hep encodes a peptide of 90 amino acids, with a predicted active peptide segment (Ma-sHep) of 25 amino acids at C terminus. Stimulation by a bacterial pathogen Aeromonas hydrophila resulted in significant up-regulation of Ma-Hep transcripts in loach midgut, head kidney, and gill. Ma-Hep and Ma-sHep proteins were expressed in Pichia pastoris and their antibacterial activity was examined. Results showed that Ma-sHep possessed stronger antibacterial activity against various Gram-positive and Gram-negative bacteria, compared to Ma-Hep. Scanning electron microscopy showed that Ma-sHep might kill bacteria by destroying bacterial cell membranes. Moreover, we found that Ma-sHep had an inhibitory effect on blood cell apoptosis induced by A. hydrophila and facilitated the bacterial phagocytosis and clearance in loach. Histopathological analysis indicated Ma-sHep could protect liver and gut of loach from bacterial infection. Ma-sHep has high thermal stability and PH stability, which is conducive to further feed addition. Feed supplemented with Ma-sHep expressing yeast improved the intestinal flora of loach by increasing the dominant bacteria and decreasing the harmful bacteria. Feed supplemented with Ma-sHep expressing yeast also regulated the expression of inflammatory related factors in various tissues of loach and reduced the mortality of loach upon bacterial infection. These findings show that the antibacterial peptide Ma-sHep is involved in the antibacterial defense of loach and can be used as a candidate for new antimicrobial agents in aquaculture.

Anemia of inflammatory: does eiderr knowledge mean better diagnosis and treatment?

Anemia, which is a manifestation of the deterioration of patients' health and performance, is a common concomitant condition in diseases with signs of inflammation activation. This anemia - anemia of inflammation, is caused by disturbances of iron metabolism that lead to iron retention within macrophages, cytokine mediated inhibition of erythropoietin function and erythroid progenitor cell differentiation, and a reduced erytrocyte half-life. Anemia is usually mild to moderate, normocytic and normochromic. It is characterized by low iron circulation, but normal to increased levels of stored ferritin and the hormone hepcidin. The primary therapeutic approach is the treatment of the underlying inflammatory disease. In case of failure, iron supplementation and / or treatment with erythropoietin stimulating agents may be used. Blood transfusions are just an emergency treatment for life-threatening anemia. A new treatment modalities with hepcidin-modifying strategies and stabilizers of hypoxia inducible factors is emerging. However, their therapeutic efficacy needs to be verified and evaluated in clinical trials.

Jian-Pi-Yi-Shen formula restores iron metabolism from dysregulation in anemic rats with adenine-induced nephropathy.

ETHNOPHARMACOLOGICAL RELEVANCE: Jian-Pi-Yi-Shen (JPYS) is a herbal decoction being used to relieve the symptoms of chronic kidney disease (CKD) and its complications, including anemia, for over twenty years. Nonetheless, it is unclear how JPYS influences renal anemia and iron metabolism. AIM OF THE STUDY: An analysis of network pharmacology, chemical profiling, and in vivo experiments was conducted to identify the impact of JPYS on JAK2-STAT3 pathway and iron utilization in renal anemia and CKD. MATERIALS AND METHODS: The chemical properties of JPYS and its exposed ingredients were detected in vivo. And based on the aforesaid chemical compounds, the potential targets and signaling pathways of JPYS for renal anemia treatment were predicted by network pharmacology. Afterward, an adenine-feeding animal model of CKD-related anemia was developed to verify the mechanism by which JPYS modulates iron recycling to treat renal anemia. Renal injury was estimated by serum creatinine (Scr), blood urea nitrogen (BUN), histopathological examinations and fibrosis degree. Western blot, enzyme-linked immunosorbent assay (ELISA), quantitative real-time polymerase chain reaction (qPCR) and immunohistochemistry approaches were utilized to assess the levels of JAK2, STAT3 and iron metabolism-related factors. RESULTS: There were 164 active ingredients identified in JPYS, including prototypes and metabolites in vivo were identified in JPYS, and 21 core targets were found through network pharmacology based on topological characteristics. Combined with the core targets and pathway enrichment analysis, the majority of the candidate targets were associated with the JAK2-STAT3 signaling pathways. Experimental results indicated that JPYS treatment significantly decreased the expression of BUN and Scr, restored renal pathological damage, down-regulated fibrosis degree, and improved hematological parameters such as red blood cell, hemoglobin and hematocrit in CKD rats. Furthermore, JPYS significantly restored iron metabolism from dysregulation by increasing the levels of iron and ferritin in the serum, inhibiting the production of hepcidin in liver and serum, and regulating transferrin receptor 1 in bone marrow. Meanwhile, the expression of JAK2 and STAT3 was suppressed by JPYS treatment. CONCLUSIONS: Based on these results, JPYS reduces hepcidin levels by inhibiting the activation of JAK2-STAT3 signaling, thereby protecting against iron deficiency anemia.

Monocyte MRI Relaxation Rates Are Regulated by Extracellular Iron and Hepcidin.

Many chronic inflammatory conditions are mediated by an increase in the number of monocytes in peripheral circulation, differentiation of monocytes to macrophages, and different macrophage subpopulations during pro- and anti-inflammatory stages of tissue injury. When hepcidin secretion is stimulated during inflammation, the iron export protein ferroportin is targeted for degradation on a limited number of cell types, including monocytes and macrophages. Such changes in monocyte iron metabolism raise the possibility of non-invasively tracking the activity of these immune cells using magnetic resonance imaging (MRI). We hypothesized that hepcidin-mediated changes in monocyte iron regulation influence both cellular iron content and MRI relaxation rates. In response to varying conditions of extracellular iron supplementation, ferroportin protein levels in human THP-1 monocytes decreased two- to eightfold, consistent with paracrine/autocrine regulation of iron export. Following hepcidin treatment, ferroportin protein levels further decreased two- to fourfold. This was accompanied by an approximately twofold increase in total transverse relaxation rate, R2*, compared to non-supplemented cells. A positive correlation between total cellular iron content and R2* improved from moderate to strong in the presence of hepcidin. These findings suggest that hepcidin-mediated changes detected in monocytes using MRI could be valuable for in vivo cell tracking of inflammatory responses.

Changes of biomarkers for erythropoiesis, iron metabolism, and FGF23 by supplementation with roxadustat in patients on hemodialysis.

This study aimed to confirm changes in biomarkers of erythropoiesis and iron metabolism and serum fibroblast growth factor 23 (FGF-23) during darbepoetin-α treatment and then switching to the hypoxia-inducible factor prolyl hydroxylase inhibitor roxadustat. A total of 28 patients on hemodialysis who received weekly doses of darbepoetin-α were switched to roxadustat. Biomarkers for erythropoiesis and iron metabolism and intact and C-terminal FGF-23 were measured in blood samples collected before the HD session on days - 7 (darbepoetin-α injection), - 4, and - 2, and days 0 (switch to roxadustat treatment, three times weekly), 3, 5, 7, 14, 21, and 28. Erythropoietin and erythroferrone levels were elevated on day - 4 by darbepoetin-α injection and decreased to baseline levels at day 0. Levels of erythropoietin were not significantly increased by roxadustat supplementation, but erythroferrone levels were continuously elevated, similar to darbepoetin-α treatment. Hepcidin-25 and total iron binding capacity were significantly decreased or increased in patients treated with roxadustat compared with darbepoetin-α. Changes of intact and C-terminal FGF-23 levels were parallel to changes of phosphate levels during roxadustat treatment. However, the actual and percentage changes of intact FGF-23 and C-terminal FGF-23 in patients with low ferritin levels were greater than those in patients with high ferritin levels. Roxadustat might stimulate erythropoiesis by increasing iron usage through hepcidin-25, which was suppressed by erythroferrone in the physiological erythropoietin condition. Changes of intact FGF-23 and C-terminal FGF-23 levels might be affected by roxadustat in patients on hemodialysis, especially those with a low-iron condition.

Absorption of iron from Tegillarca granosa using an in vitro simulated digestion and Caco-2/HepG2 co-culture system.

BACKGROUND: Iron-deficiency anemia is one severe micronutrient malnutrition and has captured worldwide attention. This study evaluated the in vitro iron absorption of two iron-binding proteins (hemoglobin and ferritin) from Tegillarca granosa. In addition, the protein structure-iron absorption relationship and the regulatory effect of hepcidin on cellular iron absorption were explored. RESULTS: Our findings revealed that both hemoglobin and ferritin extracted from T. granosa contained abundant iron-binding sites, as evidenced by stronger peaks in amide I and II regions compared with the two proteins from humans. Less ß-sheet (27.67%) structures were found in hemoglobin compared with ferritin (36.40%), probably contributing to its greater digestibility and more release of available iron. This was confirmed by the results of Caco-2/HepG2 cell culture system that showed iron absorption of hemoglobin was 26.10-39.31% higher than that of ferritin with an iron content of 50-150 µmol L-1 . This high iron absorption of hemoglobin (117.86-174.10 ng mg-1 ) could also be due to more hepcidin produced by HepG2 cells, thereby preventing ferroportin-mediated iron efflux from Caco-2 cells. In addition, the possible risk of oxidative stress was evaluated in cells post-iron exposure. In comparison with ferrous sulfate, a common iron supplement, Caco-2 cells treated with the iron-binding proteins had a 9.50-25.73% lower level of intracellular reactive oxygen species, indicating the safety of hemoglobin and ferritin. CONCLUSION: Collectively, the data of this research would be helpful for understanding the key features and potential of developing hemoglobin and ferritin from T. granosa as novel iron supplements. © 2022 Society of Chemical Industry.

Iron metabolism disorder regulated by BMP signaling in hypoxic pulmonary hypertension.

BACKGROUNDS AND AIMS: Unexplained iron deficiency is associated with poorer survival in patients with pulmonary hypertension (PH). Bone morphogenetic protein (BMP) signaling and BMP protein type II receptor (BMPR2) expression are important in the pathogenesis of PH. BMP6 in hepatocytes is a central transcriptional regulator of the iron hormone hepcidin that controls systemic iron balance. This study aimed to investigate the effects of BMP signaling on iron metabolism and its implication in hypoxia-induced PH. METHODS AND RESULTS: PH was induced in Sprague-Dawley Rats under hypoxia for 4 weeks. Compared with the control group, right ventricular systolic pressure and right ventricle hypertrophy index were both markedly increased, and serum iron level was significantly decreased with iron metabolic disorder in the hypoxia group. In cultured human pulmonary artery endothelial cells (HPAECs), hypoxia increased oxidative stress and apoptosis, which were reversed by supplementation with Fe agent. Meanwhile, iron chelator deferoxamine triggered oxidative stress and apoptosis in HPAECs, and treatment with antioxidant alleviated iron-deficiency-induced apoptosis by reducing reactive oxygen species production. Expression of hepcidin, BMP6 and hypoxia-inducible factor (HIF)-1α were significantly upregulated, while expression of BMPR2 was downregulated in hepatocytes in the hypoxia group, both in vivo and in vitro. Expression of hepcidin and HIF-1α were significantly increased by BMP6, while pretreatment with siRNA-BMPR2 augmented the enhanced expression of hepcidin and HIF-1α induced by BMP6. CONCLUSIONS: Iron deficiency promoted oxidative stress and apoptosis in HPAECs in hypoxia-induced PH, and enhanced expression of hepcidin regulated by BMP6/BMPR2 signaling may contribute to iron metabolic disorder.