Plasma hepcidin in early-stage breast cancer patients: no relationship with interleukin-6, erythropoietin and erythroferrone

Anemia, Iron Deficiency, and Iron Regulators in Pancreatic Ductal Adenocarcinoma Patients: A Comprehensive Analysis

Anemia and iron deficiency (ID) are common complications in patients with pancreatic ductal adenocarcinoma (PDAC), but their underlying causes remain unclear. This study investigated the incidence and characteristics of anemia and micronutrient deficiencies in PDAC patients before initiating chemotherapy. A total of 103 PDAC patients were included, comprising 67 in the palliative and 36 in the adjuvant groups. The overall incidence of anemia was 42.7% (n = 44), with comparable rates in both groups. Normocytic and normochromic anemia were predominant, with mild and moderate cases observed in 32% and 10.7% of the cohort, respectively. ID was evident in 51.4% of patients, with absolute ID more frequent in the adjuvant than in the palliative group (19.4% vs. 13.4%). Functional ID occurred more often in the palliative than in the adjuvant group (41.8% vs. 25%). Vitamin B12 and folate deficiency occurred in <5% (n = 5) of patients. Furthermore, 8.7% (n = 9) of patients had chronic kidney disease and anemia. To elucidate mechanisms of iron deficiency, the study explored the expression of iron regulators (hepcidin (HEP), ferroportin (FPN), and ZIP14 protein) and mitochondrial mass in PDAC tissue with immunohistochemical (IHC) staining and Perl's Prussian blue to detect iron deposits on available tumor samples (n = 56). ZIP14 expression was significantly higher in less advanced tumors (p = 0.01) and correlated with mitochondrial mass (p < 0.001), potentially indicating its role in local iron homeostasis. However, no significant impact of tissue iron regulators on patient survival was observed. Perl's Prussian blue staining revealed iron deposits within macrophages, but not in pancreatic duct cells. Furthermore, the GEPIA database was used to compare mRNA expression of iron regulators (HEP, FPN, and ZIP14) and other genes encoding iron transport and storage, including Transferrin Receptor Protein 1 (TfR1) and both ferritin chain subunits (FTH and FTL), in PDAC and normal pancreatic samples. FPN, TfR1, FTH, and FTL showed higher expression in tumor tissues, indicating increased iron usage by cancer. ZIP14 expression was higher in the pancreas than in PDAC and was correlated with FPN expression. The study highlights the importance of baseline iron status assessment in managing PDAC patients due to the high incidence of anemia and iron deficiency. Furthermore, ZIP14, in addition to HEP and FPN, may play a crucial role in local iron homeostasis in PDAC patients, providing valuable insights into the underlying mechanisms of iron dysregulation.

Iron: An Essential Element of Cancer Metabolism

Cancer cells undergo considerable metabolic changes to foster uncontrolled proliferation in a hostile environment characterized by nutrient deprivation, poor vascularization and immune infiltration. While metabolic reprogramming has been recognized as a hallmark of cancer, the role of micronutrients in shaping these adaptations remains scarcely investigated. In particular, the broad electron-transferring abilities of iron make it a versatile cofactor that is involved in a myriad of biochemical reactions vital to cellular homeostasis, including cell respiration and DNA replication. In cancer patients, systemic iron metabolism is commonly altered. Moreover, cancer cells deploy diverse mechanisms to increase iron bioavailability to fuel tumor growth. Although iron itself can readily participate in redox reactions enabling vital processes, its reactivity also gives rise to reactive oxygen species (ROS). Hence, cancer cells further rely on antioxidant mechanisms to withstand such stress. The present review provides an overview of the common alterations of iron metabolism occurring in cancer and the mechanisms through which iron promotes tumor growth.

Iron Dysregulation in Human Cancer: Altered Metabolism, Biomarkers for Diagnosis, Prognosis, Monitoring and Rationale for Therapy

Simple Summary

Iron is the more abundant metal ion in humans. It is essential for life as it has a role in various cellular processes involved, for instance, in cell metabolism and DNA synthesis. These functions are crucial for cell proliferation, and it is therefore not surprising that iron is accumulated in tumors. In this review, we describe normal and altered iron homeostasis mechanisms. We also provide a vision of iron-related proteins with altered expression in cancers and discuss their potential as diagnostic and/or prognostic biomarkers. Finally, we give an overview of therapeutic strategies acting on iron metabolism to fight against cancers.

Abstract

Iron (Fe) is a trace element that plays essential roles in various biological processes such as DNA synthesis and repair, as well as cellular energy production and oxygen transport, and it is currently widely recognized that iron homeostasis is dysregulated in many cancers. Indeed, several iron homeostasis proteins may be responsible for malignant tumor initiation, proliferation, and for the metastatic spread of tumors. A large number of studies demonstrated the potential clinical value of utilizing these deregulated proteins as prognostic and/or predictive biomarkers of malignancy and/or response to anticancer treatments. Additionally, the iron present in cancer cells and the importance of iron in ferroptosis cell death signaling pathways prompted the development of therapeutic strategies against advanced stage or resistant cancers. In this review, we select relevant and promising studies in the field of iron metabolism in cancer research and clinical oncology. Besides this, we discuss some co-existing discrepant findings. We also present and discuss the latest lines of research related to targeting iron, or its regulatory pathways, as potential promising anticancer strategies for human therapy. Iron chelators, such as deferoxamine or iron-oxide-based nanoparticles, which are already tested in clinical trials, alone or in combination with chemotherapy, are also reported.

Inflammation Mediated Hepcidin-Ferroportin Pathway and Its Therapeutic Window in Breast Cancer

Experimental and clinical data strongly support that iron is an essential element which plays a big role in cancer biology. Thus, hepcidin (Hp) and ferroportin (Fpn) are molecules that regulate and maintain the metabolism of iron. A peptide hormone hepcidin limits recycled and stored iron fluxes in macrophage and hepatic hepatocyte, respectively, to the blood stream by promoting degradation of the only iron exporter, Fpn, in the target cells. Moreover, the inflammatory microenvironment of breast cancer and altered hepcidin/ferroportin pathway is intimately linked. Breast cancer exhibits an iron seeking phenotype that is accomplished by tumor-associated macrophage (TAM). Because macrophages contribute to breast cancer growth and progression, this review will discuss TAM with an emphasis on describing how TAM (M2Ф phenotypic) interacts with their surrounding microenvironment and results in dysregulated Hp/Fpn and pathologic accumulation of iron as a hallmark of its malignant condition. Moreover, the underlying stroma or tumor microenvironment releases significant inflammatory cytokines like IL-6 and bone morphogenetic proteins like BMP-2 and 6 leading in aberrant Hp/Fpn pathways in breast cancer. Inflammation is primarily associated with the high intracellular iron levels, deregulated hepcidin/ferroportin pathway, and its upstream signaling in breast cancer. Subsequently, scholars have been reported that reducing iron level and manipulating the signaling molecules involved in iron metabolism can be used as a promising strategy of tumor chemotherapy. Here, we review the key molecular aspects of iron metabolism and its regulatory mechanisms of the hepcidin/ferroportin pathways and its current therapeutic strategies in breast cancer.

Prognostic associations of plasma hepcidin in women with early breast cancer

PURPOSE

Iron is essential to energy metabolism, cell proliferation and DNA synthesis, and sufficient iron availability may be required for tumor growth. The hormone hepcidin is a systemic regulator of iron concentration in plasma. Intra-tumor RNA expression of hepcidin has been linked to shorter metastasis-free survival in women with early breast cancer, but the prognostic implications of this inflammatory marker and iron-regulating plasma peptide in the blood are unknown.

METHODS

Using an ELISA assay, hepcidin was measured in the banked blood of 518 women who were recruited from 1989 to 1996 for a prospective cohort study of diet and lifestyle factors in breast cancer. Blood samples were obtained 4-12 weeks post-operatively, prior to treatment with chemotherapy or tamoxifen.

RESULTS

Hepcidin was not associated with time to distant breast cancer recurrence (primary outcome) nor time to death from any cause. However, a pre-planned interaction test of body mass index (BMI) was statistically significant (p < 0.01). Among obese women (BMI > 30 kg/m²), higher hepcidin was associated with a shorter time to distant breast cancer recurrence in both uni- and multivariable analyses (adjusted HR 1.84; 95% CI 1.04-3.25). For overall survival, a similar pattern was seen in the univariable model but the effect was diminished in a multivariable analysis. Plasma hepcidin was not associated with high-sensitivity C-reactive protein, but it was significantly associated (r ≥ 0.32) with iron indices, including total iron (p < 0.01), transferrin (p < 0.01) and soluble transferrin receptor (p < 0.01).

CONCLUSIONS

Hepcidin may be associated with poor breast cancer outcome in obese women, however, replication is required. The biologic basis for this prognostic association requires further research.

Adenomatous polyposis coli-binding protein end-binding 1 promotes hepatocellular carcinoma growth and metastasis

This study was performed to determine the clinical significance of adenomatous polyposis coli (APC)-binding protein end-binding 1 (EB1) in hepatocellular carcinoma (HCC) and to characterize its biochemical role in comparison with previous reports. We performed immunohistochemical staining to detect EB1 expression in tissues from 235 patients with HCC and investigated its correlations with clinicopathological features and prognosis. We also investigated the roles of EB1 in cell proliferation, migration, and tumorigenesis in vitro and in vivo by siRNA- and CRISPR/Cas9-mediated modulation of EB1 expression in human HCC cell lines. The results showed that EB1 expression was significantly correlated with several important factors associated with tumor malignancy, including histological differentiation, portal vein invasion status, and intrahepatic metastasis. Patients with high EB1 expression in HCC tissue had poorer overall survival and higher recurrence rates than patients with low EB1 expression. EB1 knockdown and knockout in HCC cells reduced cell proliferation, migration, and invasion in vitro and inhibited tumor growth in vivo. Further, genes encoding Dlk1, HAMP, and SLCO1B3 that were differentially expressed in association with EB1 were identified using RNA microarray analysis. In conclusion, elevated expression of EB1 promotes tumor growth and metastasis of HCC. EB1 may serve as a new biomarker for HCC, and genes coexpressed with EB1 may represent potential targets for therapy.

The effect of red blood cell transfusion on plasma hepcidin and growth differentiation factor 15 in gastric cancer patients: a prospective study

Background

Hepcidin and growth differentiation factor 15 (GDF-15) have been reported to be highly expressed in various cancers. Serum hepcidin and GDF-15 levels were demonstrated to be potential prognostic markers in cancers. This study aims to evaluate the effect of red blood cell (RBC) transfusion on plasma hepcidin and GDF-15 in gastric cancer patients.

Methods

In this prospective study, 40 patients with gastric cancer were eligible for this study. Peripheral blood samples were obtained before and within 24 h after RBC transfusion. A routine blood test was performed before transfusion and within 24 h post-transfusion. Plasma hepcidin, GDF-15, interleukin 6 (IL-6) and erythropoietin were determined by ELISA.

Results

In patients with metastasis, plasma hepcidin (P=0.02), and GDF-15 (P=0.01) levels were higher than without metastasis. Plasma hepcidin was increased after RBC transfusion (P=0.001), while plasma erythropoietin was decreased after transfusion (P=0.03). However, RBC transfusion did not affect plasma GDF-15 (P=0.32) and IL-6 (P=0.12). The effect of RBC transfusion on variables did not differ between metastatic and non-metastatic patients. The mean percentage change of hepcidin in transfusion volume 4 unit (U) was more than 2 U.

Conclusions

RBC transfusion could increase plasma hepcidin and have no effect on plasma GDF-15 in gastric patients.

Association of iron metabolic enzyme hepcidin expression levels with the prognosis of patients with pancreatic cancer

Hepcidin and ferroportin, which are known as key iron regulators, may be used in future treatments of pancreatic ductal adenocarcinoma. Iron is essential for life support; it helps oxygen molecules bind to hemoglobin and acts as an important catalytic enzyme center. However, iron overload is a risk factor for cancer, possibly through the generation of reactive oxygen species (ROS). Hepcidin, which is a peptide hormone mainly generated by the liver, inhibits iron absorption via enterocytes and iron release from macrophages. Notably, hepcidin regulates iron homeostasis in the body by regulating the iron transporter ferroportin. In the present study, it was assumed that high hepcidin expression and low ferroportin expression result in malignancy. Therefore, it was examined whether hepcidin and ferroportin expression levels were correlated with the prognosis of pancreatic cancer in patients. Results revealed that high hepcidin expression levels and low ferroportin expression levels in pancreatic cancer tissue were significantly associated with poor prognosis in the analyses of overall survival (P=0.0140 and 0.0478, respectively). Additionally, there was no significant difference in disease-free survival in the hepcidin- and ferroportin-staining groups. Hepcidin expression correlated with the pathological stage and vascular invasion (P=0.0493 and 0.0400, respectively), and ferroportin expression was correlated with age (P=0.0372). Multivariate analysis of overall survival in the hepcidin-staining group revealed that pathological N factor (pN), adjuvant chemotherapy, and hepcidin expression were independent prognostic factors (P=0.0450, 0.0002, and 0.0049, respectively). Similarly, multivariate analysis of overall survival in the ferroportin-staining group revealed that vascular invasion, and ferroportin expression were independent prognostic factors (P=0.0028, P<0.0001, and P=0.0056, respectively). Thus, hepcidin and ferroportin expressions might be novel prognostic indicators for pancreatic cancer.

Erythroferrone and iron status parameters levels in pediatric patients with iron deficiency anemia

OBJECTIVES

To investigate the link between serum erythroferrone (ERFE) levels and iron status parameters in pediatric patients with iron deficiency anemia.

METHODS

The study consisted of 66 children (36 with iron deficiency anemia and 30 healthy age- and gender-matched controls) who were investigated for serum levels of iron, total iron-binding capacity (TIBC) using automated chemistry analyzer, serum ferritin using electrochemiluminescence immunoassay and ERFE by specific enzyme-linked immunosorbent assay (ELISA) kit.

RESULTS

Serum erythroferrone levels in iron deficiency anemia patients (191.55 ± 83.74 pg/mL) were significantly higher than those in control group (42.22 ± 16.55 pg/mL) (P < .001). In iron deficiency anemia patients, serum erythroferrone concentrations correlated negatively with hemoglobin concentration (r = -.39; P = .01), serum iron (r = -.63; P < .001), transferrin saturation (r = -.66; P < .001), and serum ferritin (r = -.46; P = .004) while positive correlation was observed between serum erythroferrone concentrations and TIBC (r = .62; P < .001) CONCLUSION: The newly identified erythroferrone hormone may act as physiological hepcidin suppressor in cases with iron deficiency anemia, and so it may serve as a specific promising target of therapy in such cases.

Differential regulation of hepcidin in cancer and non-cancer tissues and its clinical implications

Hepcidin is a crucial peptide for regulating cellular iron efflux. Because iron is essential for cell survival, especially for highly active cells, such as tumor cells, it is imperative to understand how tumor cells manipulate hepcidin expression for their own metabolic needs. Studies suggest that hepcidin expression and regulation in tumor cells show important differences in comparison with those in non-tumorous cells. These differences should be investigated to develop new strategies to fight cancer cells. Manipulating hepcidin expression to starve cancer cells for iron may prove to be a new therapy in the anticancer arsenal.

Increased expression of hepcidin and associated upregulation of JAK/STAT3 signaling in human gastric cancer

Gastric cancer is one of the most common malignancies with high cancer-associated mortality rate globally. Hepcidin is the peptide hormone, which is critically important in the regulation of systemic iron homeostasis. Cumulating evidence has reported that the disturbed local expression of hepcidin may serve as a predictive biomarker in assessing the clinical outcomes in a range of cancer types. However, the expression profile of hepcidin in human gastric cancer is remains to be investigated. In the present retrospective study, using archived paraffin-embedded tissue blocks, the local production of hepcidin by immunohistochemical analysis was detected, and then its correlation with clinicopathological characteristics in human gastric cancer was evaluated. In parallel, using western blotting, quantitative reverse transcription polymerase chain reaction and chromatin immunoprecipitation assay, the local status of Janus kinase (JAK)/signal transducer and activator of transcription 3 (STAT3) signaling in response to inflammatory stimuli mediated by interleukin (IL)-6, which in turn regulates transcriptional activity of hepcidin gene (HAMP) was also assessed. The results indicated that, the local production of hepcidin was significantly elevated in tumor tissues compared with adjacent non-tumor tissues, and was tightly correlated with increasing tumor stages according to the tumor node metastasis (TNM) classification. In addition, JAK/STAT3 signaling and the STAT3 binding affinity to the HAMP gene promoter were significantly enhanced, in parallel with an increased expression of hepcidin, in tumor tissues compared with adjacent non-tumor tissues. Collectively, the present study indicated that local expression of hepcidin in gastric cancer tumor tissues was positively correlated with increasing tumor stages, which may be closely associated with the upregulation of IL-6-mediated JAK/STAT3 signaling in human gastric cancer.

Potential humoral mediators of remote ischemic preconditioning in patients undergoing surgical coronary revascularization

Remote ischemic preconditioning (RIPC) by repeated brief cycles of limb ischemia/reperfusion may reduce myocardial ischemia/reperfusion injury and improve patients‘ prognosis after elective coronary artery bypass graft (CABG) surgery. The signal transducer and activator of transcription (STAT)5 activation in left ventricular myocardium is associated with RIPC´s cardioprotection. Cytokines and growth hormones typically activate STATs and could therefore act as humoral transfer factors of RIPC´s cardioprotection. We here determined arterial plasma concentrations of 25 different cytokines, growth hormones, and other factors which have previously been associated with cardioprotection, before (baseline)/after RIPC or placebo (n = 23/23), respectively, and before/after ischemic cardioplegic arrest in CABG patients. RIPC-induced protection was reflected by a 35% reduction of serum troponin I release. With the exception of interleukin-1α, none of the humoral factors changed in their concentrations after RIPC or placebo, respectively. Interleukin-1α, when normalized to baseline, increased after RIPC (280 ± 56%) but not with placebo (97 ± 15%). The interleukin-1α concentration remained increased until after ischemic cardioplegic arrest and was also higher than with placebo in absolute concentrations (25 ± 6 versus 16 ± 3 pg/mL). Only interleukin-1α possibly fulfills the criteria which would be expected from a substance to be released in response to RIPC and to protect the myocardium during ischemic cardioplegic arrest.

Expression of Iron-Related Proteins Differentiate Non-Cancerous and Cancerous Breast Tumors

We have previously reported hepcidin and ferritin increases in the plasma of breast cancer patients, but not in patients with benign breast disease. We hypothesized that these differences in systemic iron homeostasis may reflect alterations in different iron-related proteins also play a key biochemical and regulatory role in breast cancer. Thus, here we explored the expression of a bundle of molecules involved in both iron homeostasis and tumorigenesis in tissue samples. Enzyme-linked immunosorbent assay (ELISA) or reverse-phase protein array (RPPA), were used to measure the expression of 20 proteins linked to iron processes in 24 non-cancerous, and 56 cancerous, breast tumors. We found that cancerous tissues had higher level of hepcidin than benign lesions (p = 0.012). The univariate analysis of RPPA data highlighted the following seven proteins differentially expressed between non-cancerous and cancerous breast tissue: signal transducer and transcriptional activator 5 (STAT5), signal transducer and activator of transcription 3 (STAT3), bone morphogenetic protein 6 (BMP6), cluster of differentiation 74 (CD74), transferrin receptor (TFRC), inhibin alpha (INHA), and STAT5_pY694. These findings were confirmed for STAT5, STAT3, BMP6, CD74 and INHA when adjusting for age. The multivariate statistical analysis indicated an iron-related 10-protein panel effective in separating non-cancerous from cancerous lesions including STAT5, STAT5_pY694, myeloid differentiation factor 88 (MYD88), CD74, iron exporter ferroportin (FPN), high mobility group box 1 (HMGB1), STAT3_pS727, TFRC, ferritin heavy chain (FTH), and ferritin light chain (FTL). Our results showed an association between some iron-related proteins and the type of tumor tissue, which may provide insight in strategies for using iron chelators to treat breast cancer.

Protective effects of the roots of Angelica sinensis on strenuous exercise-induced sports anemia in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Sports anemia is a persistent and severe problem in athletes owing to strenuous exercise-induced oxidative stress and hepcidin upregulation. The roots of Angelica sinensis (AS), a familiar traditional Chinese medicine, has been used for replenishing blood since antiquity.

AIM OF THE STUDY

To evaluate the effects of ethanolic AS extract in a 4-week study on sports anemia in female Wistar rats.

MATERIALS AND METHODS

To induce anemia, a strenuous exercise protocol consisting of running and swimming was employed with increasing intensity. Animals were randomly assigned to the following groups: control group; strenuous exercise group; and strenuous exercise and AS extract-treated group (300mgkg^-1d^-1). After 4 weeks, rats underwent exhaustive swimming and forelimb grip strength test. The blood biochemical markers and hepatic antioxidant activities were determined. Hepatic interleukin-6 and muscle glycogen were observed through immunohistochemical and Periodic acid-Schiff staining, respectively.

RESULTS

AS extract (consisting of ferulic acid, Z-ligustilide, and n-butylidenephthalide) treatment improved forelimb grip strength and rescued exercise-induced anemia by significantly elevating the red blood cell counts and hemoglobin concentrations as well as hematocrit levels (p<0.05). AS modulated the iron metabolism through decreasing serum hepcidin-25 concentrations by 33.0% (p<0.05) and increasing serum iron levels by 34.3% (p<0.01). The hepatic injury marker serum alanine aminotransferase concentrations were also reduced, followed by increased antioxidant enzyme catalase expression in the liver (p<0.05). Furthermore, substantial attenuation of hepatic interleukin-6 expression and preservation of muscle glycogen content suggested the additional roles of AS acting on sports anemia and physical performance.

CONCLUSION

Our findings evidenced a novel and promising therapeutic approach for AS treatment for rescuing the anemic condition induced following 4 weeks of strenuous exercise.

The interleukin-6-hepcidin-hemoglobin circuit in systemic lupus erythematosus flares

Objective Hepcidin regulates iron availability and may be responsible for the anemia of chronic disease because it is induced by interleukin-6. This study investigated the IL-6-hepcidin-hemoglobin axis in patients with lupus. Methods IL-6 and hepcidin were measured in serial serum samples collected before, during and after lupus flares by specific ELISAs. Results During renal and non-renal SLE flare cycles IL-6 did not predict hepcidin and hepcidin did not predict hemoglobin. When lupus nephritis patients were in remission, IL-6 and hepcidin were correlated, but hepcidin and hemoglobin were not. Conclusion Hepcidin does not contribute significantly to anemia during active lupus.

Assessment of serum bioactive hepcidin-25, soluble transferrin receptor and their ratio in predialysis patients: Correlation with the response to intravenous ferric carboxymaltose

BACKGROUND

No reliable biomarker exists to predict responsiveness to intravenous (IV) iron (Fe) in iron deficient patients with CKD. We aimed to investigate the clinical value of bioactive Hepcidin-25 and soluble Transferrin Receptor (sTfR) levels in predialysis patients.

PATIENTS AND METHODS

In this prospective study 78 stable stage III-IV CKD predialysis patients with (responders) (40 patients) and without (non-responders) (38 patients) adequate erythropoiesis after IV administration of ferric-carboxymaltose (FCM). Patients were divided in two groups according to their response to IV administration of ferric-carboxymaltose (FCM). Along with measurements of common hematologic and blood chemistry parameters, determinations of sTfR and bioactive Hepcidin-25 were performed.

RESULTS

Hepcidin-25 levels were lower in the responders (p=0.025), while sTfR and sTfR/Hepcidin-25 ratio were higher (p<0.01 and p=0.002 respectively). Diagnostic efficacy indicated cut off point of 1.49 for Hepcidin-25 had sensitivity 84% and specificity 48%, while cut off point of 1.21 for sTfR/Hepcidin-25 ratio had sensitivity 82% and specificity 52% to predict correctly response to iron supplementation therapy. Furthermore, log sTfR/Hepcidin-25 correlated negatively with hs-CRP (p=0.005) and IL-6 (p<0.04) in non-responders, while such correlations were not found in responders (p>0.05).

CONCLUSIONS

These results suggest that lower Hepcidin-25, as well as higher sTfR and sTfR/Hepcidin-25 ratio were significant predictors of favorable hemoglobin response within a month after IV administration of FCM in patients with CKD. Further experiments and clinical studies in other groups of patients are needed to better elucidate the role of Hepcidin-25 and sTfR/Hepcidin-25 ratio as predictors of response to intravenous iron administration.

Associations among Erythroferrone and Biomarkers of Erythropoiesis and Iron Metabolism, and Treatment with Long-Term Erythropoiesis-Stimulating Agents in Patients on Hemodialysis

BACKGROUND

We aimed to identify associations between erythroferrone (ERFE), a regulator of hepcidin 25, and biomarkers of erythropoiesis and iron metabolism. We also aimed to determine the effects of erythropoiesis-stimulating agents (ESA), continuous erythropoietin receptor activator (CERA) and darbepoetin-α (DA) on ERFE production in patients on hemodialysis (HD).

METHODS

Blood samples were obtained from 59 patients before HD sessions on day 0 (baseline). Twenty patients who were injected with either CERA (N = 10) or DA (N = 10) at the end of the dialysis week (day 0), who had ferritin ≥ 100 ng/mL and/or transferrin saturation ≥ 20%, and hemoglobin > 9 g/dL were selected from among the 59 patients. Blood was sampled serially before HD sessions on days 3, 5, 7 from patients on DA and on the same days plus day 14 from those on CERA.

RESULTS

Levels of ERFE correlated inversely with those of hepcidin 25 and ferritin, and positively with those of soluble transferrin receptor. The hepcidin 25: ERFE ratio and hepcidin 25 levels positively correlated with ferritin levels. Levels of ERFE significantly increased from day 3 of treatment with DA and CERA and decreased by days 7 and 14, respectively. Erythropoiesis-stimulating agents concomitantly decreased levels of hepcidin 25 as those of ERFE increased.

CONCLUSION

We identified a novel association between ESA and ERFE in patients on HD. Both DA and CERA increased levels of ERFE that regulated hepcidin 25 and led to iron mobilization from body stores during erythropoiesis.