High Ferritin Is Not Needed in Hemodialysis Patients: A Retrospective Study of Total Body Iron and Oral Iron Replacement Therapy.

In vivo iron levels can be adjusted through intestinal iron absorption to be maintained at a suitable level; however, optimal iron levels in hemodialysis (HD) patients are unclear. In this study, we investigated total body iron (TBI), calculated as the sum of red blood cell (RBC) iron and iron stores, during courses of low-dose oral iron replacement therapy, and evaluated in vivo iron sufficiency and its indicators in HD patients. We analyzed data on 105 courses of low-dose iron replacement therapy administered to 83 patients on maintenance HD over 7 months. We evaluated changes in TBI, RBC iron, and iron stores from the initiation of treatment to month 7 in two groups of patients, namely, iron-therapy responders and non-responders. TBI showed significant increases until month 4 and plateaued thereafter in iron-therapy responders, and tended to increase and then reached a similar plateau in non-responders (month 7: 1900 ± 447 vs. 1900 ± 408 mg). Steady-state TBI was strongly correlated with body surface area (y = 1628.6x - 791.91, R2 = 0.88, p < 0.001). We observed constant TBI during oral iron replacement therapy suggesting the activation of a "mucosal block". The results suggest that body surface area has utility for estimating the required TBI with regression equations.

Gentle, Massage-like, Head Stroking Provokes Salivary Oxytocin Release.

Context: The evidence is growing that oxytocin (OXT), a hypothalamic hormone, can induce parturition and lactation, modulate affiliative behavior, and regulate stress and energy metabolism. Although the physiological effects of massage aren't fully understood, massage may affect OXT release and facilitate adaptive responses to stressors. Objectives: This study intended to examine the effects of gentle, massage-like head, stroking to determine whether it could have a direct influence on the release of OXT. Design: The research team performed a preliminary study. Setting: The study was conducted at Kanazawa Medical University in Kahoku and Mizuho Hospital, Tsubata, Ishikawa, Japan. Participants: Participants were 14 volunteers from Mizuho Hospital. Intervention: The 14 recruited participants were assigned to the massage group and received gentle, massage-like, head stroking, which lasted 60 minutes. Seven of those participants were randomly recruited to become a control group that rested only, without massage, on a different day than the massage occurred. Outcome Measures: Participants' saliva for both groups was drawn at baseline and postintervention on the different days. Salivary OXT was assayed using a highly sensitive chemiluminescence immunoassay. Analyses were performed at baseline before the intervention and postintervention. Results: The OXT secretion increased significantly in the massage group unlike in the rest group, which had no change. Conclusions: Gentle, massage-like, head stroking is an effective method of releasing endogenous OXT. These findings open up the possibility of using endogenous OXT as an adjunct therapy in both clinical and research settings.

Oral Iron Absorption of Ferric Citrate Hydrate and Hepcidin-25 in Hemodialysis Patients: A Prospective, Multicenter, Observational Riona-Oral Iron Absorption Trial.

Oral ferric citrate hydrate (FCH) is effective for iron deficiencies in hemodialysis patients; however, how iron balance in the body affects iron absorption in the intestinal tract remains unclear. This prospective observational study (Riona-Oral Iron Absorption Trial, R-OIAT, UMIN 000031406) was conducted at 42 hemodialysis centers in Japan, wherein 268 hemodialysis patients without inflammation were enrolled and treated with a fixed amount of FCH for 6 months. We assessed the predictive value of hepcidin-25 for iron absorption and iron shift between ferritin (FTN) and red blood cells (RBCs) following FCH therapy. Serum iron changes at 2 h (ΔFe2h) after FCH ingestion were evaluated as iron absorption. The primary outcome was the quantitative delineation of iron variables with respect to ΔFe2h, and the secondary outcome was the description of the predictors of the body's iron balance. Generalized estimating equations (GEEs) were used to identify the determinants of iron absorption during each phase of FCH treatment. ΔFe2h increased when hepcidin-25 and TSAT decreased (-0.459, -0.643 to -0.276, p = 0.000; -0.648, -1.099 to -0.197, p = 0.005, respectively) in GEEs. FTN increased when RBCs decreased (-1.392, -1.749 to -1.035, p = 0.000) and hepcidin-25 increased (0.297, 0.239 to 0.355, p = 0.000). Limiting erythropoiesis to maintain hemoglobin levels induces RBC reduction in hemodialysis patients, resulting in increased hepcidin-25 and FTN levels. Hepcidin-25 production may prompt an iron shift from RBC iron to FTN iron, inhibiting iron absorption even with continued FCH intake.

Threshold of Serum Ferritin to Discriminate against Those at Greater Risk of Platelet Increase during Treatment with Hypoxia-Inducible Factor Prolyl Hydroxylase Domain Inhibitor.

INTRODUCTION: Hypoxia-inducible factor prolyl hydroxylase domain inhibitors (HIF-PHI) are a new treatment for renal anemia. HIF-PHI is believed to increase iron usage to improve availability of iron for erythropoiesis. Therefore, there is concern that HIF-PHI might be prone to iron deficiency and that thrombosis might be induced by increased platelet and transferrin levels due to this iron deficiency. METHODS: Relationship of iron-related factors with platelet count (PLT) and total iron-binding capacity (TIBC; which reflects the transferrin level) were examined in 29 patients who were treated with darbepoetin alfa (DA) and then switched to roxadustat (Rox). To determine how changes in PLT and TIBC related to changes in iron-related factors, univariable and multivariable linear regression models were applied. To examine what iron-related factors on Day 0 influenced change in PLT, we used receiver operating characteristic (ROC) curves and logistic regression analysis for a rate of change in PLT ≤0% as the endpoint. Logistic regression analysis was performed with the reference group having serum ferritin (s-ft) or Transferrin saturation below the corresponding cutoff value (low vs. high). RESULTS: Multivariable analysis showed significant positive correlations between the rate of change in PLT and the change in s-ft and red blood cells (RBC) count {ß-coefficients; 0.40 [95% confidence interval (CI): 0.17-0.62], p = 0.001} (ß-coefficients; 30.45 [95% CI: 10.90-50.00], p = 0.004). The rate of change in TIBC was significantly positively correlated with only the change in RBC count. The ROC showed a significant cutoff value for s-ft of 77.2 ng/mL (sensitivity 63.6%, specificity 83.3%, area under the curve 0.76, 95% CI 0.55-0.96). Multivariable logistic regression also showed that only high s-ft was significantly elevated (9.46, 95% CI 1.42-63.30, p = 0.020). CONCLUSIONS: This study showed that changes in PLT were correlated with s-ft and amount of hematopoiesis. This suggests that an increase in PLT due to iron levels is less likely when s-ft is 77.2 ng/mL or higher at the time of switching from DA to Rox. In contrast, TIBC was only related to hematopoiesis in these patients. Control of s-ft before initiation of HIF-PHI treatment and gradual hematopoiesis might reduce the risk of thrombosis when switching from erythropoiesis-stimulating agents to HIF-PHI.

GLCCI1 is a novel protector against glucocorticoid-induced apoptosis in T cells.

Glucocorticoids (GCs) potently induce T-cell apoptosis in a GC receptor (GR)-dependent manner and are used to control lymphocyte function in clinical practice. However, its downstream pathways remain controversial. Here, we showed that GC-induced transcript 1 (GLCCI1) is a novel downstream molecule of the GC-GR cascade that acts as an antiapoptotic mediator in thymic T cells. GLCCI1 was highly phosphorylated and colocalized with microtubules in GLCCI1-transfected human embryonic kidney QBI293A cells. GR-dependent up-regulation of GLCCI1 was associated with GC-induced proapoptotic events in a cultured thymocyte cell line. However, GLCCI1 knockdown in a thymocyte cell line led to apoptosis. Consistently, transgenic mice overexpressing human GLCCI1 displayed enlarged thymi that consisted of larger numbers of thymocytes. Further molecular characterization showed that GLCCI1 bound to both dynein light chain LC8-type 1 (LC8) and its functional kinase, p21-protein activated kinase 1 (PAK1), thereby inhibiting the kinase activity of PAK1 toward LC8 phosphorylation, a crucial event in apoptotic signaling. GLCCI1 induction facilitated LC8 dimer formation and reduced Bim expression. Thus, GLCCI1 is a candidate factor involved in apoptosis regulation of thymic T cells.-Kiuchi, Z., Nishibori, Y., Kutsuna, S., Kotani, M., Hada, I., Kimura, T., Fukutomi, T., Fukuhara, D., Ito-Nitta, N., Kudo, A., Takata, T., Ishigaki, Y., Tomosugi, N., Tanaka, H., Matsushima, S., Ogasawara, S., Hirayama, Y., Takematsu, H., Yan, K. GLCCI1 is a novel protector against glucocorticoid-induced apoptosis in T cells.

Optimizing hepcidin measurement with a proficiency test framework and standardization improvement.

Objectives: Hepcidin measurement advances insights in pathophysiology, diagnosis, and treatment of iron disorders, but requires analytically sound and standardized measurement procedures (MPs). Recent development of a two-level secondary reference material (sRM) for hepcidin assays allows worldwide standardization. However, no proficiency testing (PT) schemes to ensure external quality assurance (EQA) exist and the absence of a high calibrator in the sRM set precludes optimal standardization. Methods: We developed a pilot PT together with the Dutch EQA organization Stichting Kwaliteitsbewaking Medische Laboratoriumdiagnostiek (SKML) that included 16 international hepcidin MPs. The design included 12 human serum samples that allowed us to evaluate accuracy, linearity, precision and standardization potential. We manufactured, value-assigned, and validated a high-level calibrator in a similar manner to the existing low- and middle-level sRM. Results: The pilot PT confirmed logistical feasibility of an annual scheme. Most MPs demonstrated linearity (R2>0.99) and precision (duplicate CV>12.2%), although the need for EQA was shown by large variability in accuracy. The high-level calibrator proved effective, reducing the inter-assay CV from 42.0% (unstandardized) to 14.0%, compared to 17.6% with the two-leveled set. The calibrator passed international homogeneity criteria and was assigned a value of 9.07±0.24 nmol/L. Conclusions: We established a framework for future PT to enable laboratory accreditation, which is essential to ensure quality of hepcidin measurement and its use in patient care. Additionally, we showed optimized standardization is possible by extending the current sRM with a third high calibrator, although international implementation of the sRM is a prerequisite for its success.

A Hypoxia-Inducible Factor Stabilizer Improves Hematopoiesis and Iron Metabolism Early after Administration to Treat Anemia in Hemodialysis Patients.

Roxadustat (Rox), a hypoxia-inducible factor (HIF) stabilizer, is now available for the treatment of anemia in hemodialysis (HD) patients. To investigate hematopoietic effect and iron metabolism, this study involved 30 HD patients who were initially treated with darbepoetin (DA), a conventional erythropoietin-stimulating agent, and then switched to Rox. We measured erythrocyte, reticulocyte indices, and iron-related factors at every HD during the first two weeks after the treatment switch (Days 0-14) and again on Days 21 and 28. We measured erythropoietin (EPO) concentration every week and examined their changes from Day-0 values. The same variables were measured in 15 HD patients who continued DA at every HD for one week. Iron-related factors were also measured on Days 14 and 28. In the Rox group, hepcidin significantly decreased from Day 2. The reticulocyte hemoglobin content (CHr) significantly increased on Day 4, but decreased with a significant increase in reticulocyte count from Day 7. Log10(serum ferritin) significantly decreased after Day 11. Log10(EPO concentration) was lower at all time points. Compared with the DA group, the Rox group showed significant differences in all variables except CHr. These results suggest that Rox improves hematopoiesis and iron metabolism early after administration independent of EPO concentration.

Provisional standardization of hepcidin assays: creating a traceability chain with a primary reference material, candidate reference method and a commutable secondary reference material.

Background Hepcidin concentrations measured by various methods differ considerably, complicating interpretation. Here, a previously identified plasma-based candidate secondary reference material (csRM) was modified into a serum-based two-leveled sRM. We validated its functionality to increase the equivalence between methods for international standardization. Methods We applied technical procedures developed by the International Consortium for Harmonization of Clinical Laboratory Results. The sRM, consisting of lyophilized serum with cryolyoprotectant, appeared commutable among nine different measurement procedures using 16 native human serum samples in a first round robin (RR1). Harmonization potential of the sRM was simulated in RR1 and evaluated in practice in RR2 among 11 measurement procedures using three native human plasma samples. Comprehensive purity analysis of a candidate primary RM (cpRM) was performed by state of the art procedures. The sRM was value assigned with an isotope dilution mass spectrometry-based candidate reference method calibrated using the certified pRM. Results The inter-assay CV without harmonization was 42.1% and 52.8% in RR1 and RR2, respectively. In RR1, simulation of harmonization with sRM resulted in an inter-assay CV of 11.0%, whereas in RR2 calibration with the material resulted in an inter-assay CV of 19.1%. Both the sRM and pRM passed international homogeneity criteria and showed long-term stability. We assigned values to the low (0.95±0.11 nmol/L) and middle concentration (3.75±0.17 nmol/L) calibrators of the sRM. Conclusions Standardization of hepcidin is possible with our sRM, which value is assigned by a pRM. We propose the implementation of this material as an international calibrator for hepcidin.

Differential Impacts of Intravenous Iron Administration and Iron-Containing Phosphate Binders on Serum Intact Fibroblast Growth Factor 23 Levels.

AIMS: This study assessed the impact of iron administration on serum fibroblast growth factor 23 (FGF23) levels. METHODS: Of 123 hemodialysis (HD) patients treated with erythropoiesis-stimulating agents, 22 received once-weekly intravenous iron and 17 received daily oral iron with iron-containing phosphate binders. Intact FGF23 and biomarkers of iron metabolism were measured from blood samples drawn before each HD session, at baseline and on days 3, 5, 7, and 14. RESULTS: Phosphate levels did not differ among the 3 groups during the 14-day period. Ferritin levels were significantly increased in both iron treatment groups compared with the non-iron treatment group, but changes in transferrin saturation levels were similar in the intravenous iron and non-iron groups. However, intact FGF23 levels were continuously higher in the intravenous iron group than those in the other groups. CONCLUSION: Intravenous iron administration may influence intact FGF23 levels in HD patients independently of phosphate and iron metabolism.

Iron-heme-Bach1 axis is involved in erythroblast adaptation to iron deficiency.

Iron plays the central role in oxygen transport by erythrocytes as a constituent of heme and hemoglobin. The importance of iron and heme is also to be found in their regulatory roles during erythroblast maturation. The transcription factor Bach1 may be involved in their regulatory roles since it is deactivated by direct binding of heme. To address whether Bach1 is involved in the responses of erythroblasts to iron status, low iron conditions that induced severe iron deficiency in mice were established. Under iron deficiency, extensive gene expression changes and mitophagy disorder were induced during maturation of erythroblasts. Bach1-/- mice showed more severe iron deficiency anemia in the developmental phase of mice and a retarded recovery once iron was replenished when compared with wild-type mice. In the absence of Bach1, the expression of globin genes and Hmox1 (encoding heme oxygenase-1) was de-repressed in erythroblasts under iron deficiency, suggesting that Bach1 represses these genes in erythroblasts under iron deficiency to balance the levels of heme and globin. Moreover, an increase in genome-wide DNA methylation was observed in erythroblasts of Bach1-/- mice under iron deficiency. These findings reveal the principle role of iron as a regulator of gene expression in erythroblast maturation and suggest that the iron-heme-Bach1 axis is important for a proper adaptation of erythroblast to iron deficiency to avoid toxic aggregates of non-heme globin.

Toward Worldwide Hepcidin Assay Harmonization: Identification of a Commutable Secondary Reference Material.

BACKGROUND: Absolute plasma hepcidin concentrations measured by various procedures differ substantially, complicating interpretation of results and rendering reference intervals method dependent. We investigated the degree of equivalence achievable by harmonization and the identification of a commutable secondary reference material to accomplish this goal. METHODS: We applied technical procedures to achieve harmonization developed by the Consortium for Harmonization of Clinical Laboratory Results. Eleven plasma hepcidin measurement procedures (5 mass spectrometry based and 6 immunochemical based) quantified native individual plasma samples (n = 32) and native plasma pools (n = 8) to assess analytical performance and current and achievable equivalence. In addition, 8 types of candidate reference materials (3 concentrations each, n = 24) were assessed for their suitability, most notably in terms of commutability, to serve as secondary reference material. RESULTS: Absolute hepcidin values and reproducibility (intrameasurement procedure CVs 2.9%-8.7%) differed substantially between measurement procedures, but all were linear and correlated well. The current equivalence (intermeasurement procedure CV 28.6%) between the methods was mainly attributable to differences in calibration and could thus be improved by harmonization with a common calibrator. Linear regression analysis and standardized residuals showed that a candidate reference material consisting of native lyophilized plasma with cryolyoprotectant was commutable for all measurement procedures. Mathematically simulated harmonization with this calibrator resulted in a maximum achievable equivalence of 7.7%. CONCLUSIONS: The secondary reference material identified in this study has the potential to substantially improve equivalence between hepcidin measurement procedures and contributes to the establishment of a traceability chain that will ultimately allow standardization of hepcidin measurement results.

Regulation of soluble Flt-1 (VEGFR-1) production by hnRNP D and protein arginine methylation.

Soluble fms-like tyrosine kinase-1 (sFlt-1) functions as a potent inhibitor of angiogenesis by trapping vascular endothelial growth factor (VEGF). However, the precise regulatory mechanism of sFlt-1 production is unknown. Here, we report that vascular sFlt-1 production is regulated by heterogeneous nuclear ribonucleoprotein D (hnRNP D) and arginine methylation. We showed that hnRNP D bound to Flt-1 pre-mRNA and that hnRNP D overexpression decreased sFlt-1 mRNA in human microvascular endothelial cells (HMVECs). In contrast, the reduction of hnRNP D levels induced an increase in sFlt-1 production. Overexpression of an hnRNP D mutant in which the arginine residue of the known arginine methylation motif (arginine-glycine-glycine; RGG) was replaced with alanine did not reduce the level of soluble-form RNA produced from the Flt-1 minigene. Moreover, we demonstrated that overexpression of arginine methyltransferase decreased the soluble-form RNA level, whereas overexpression of arginine demethylase and addition of methyltransferase inhibitors increased sFlt-1 mRNA levels. These findings indicate that hnRNP D and arginine methylation play important roles in the regulation of Flt-1 mRNA alternative polyadenylation.

RNA-binding protein RBM8A (Y14) and MAGOH localize to centrosome in human A549 cells.

RBM8A (Y14) is carrying RNA-binding motif and forms the tight heterodimer with MAGOH. The heterodimer is known to be a member of exon junction complex on exporting mRNA and is required for mRNA metabolisms such as splicing, mRNA export and nonsense-mediated mRNA decay. Almost all RBM8A-MAGOH complexes localize in nucleoplasm and shuttle between nuclei and cytoplasm for RNA metabolism. Recently, the abnormality of G2/M transition and aberrant centrosome regulation in RBM8A- or MAGOH-deficient cells has been reported. These results prompt us to the reevaluation of the localization of RBM8A-MAGOH in human cells. Interestingly, our immunostaining experiments showed the localization of these proteins in centrosome in addition to nuclei. Furthermore, the transiently expressed eYFP-tagged RBM8A and Flag-tagged MAGOH also co-localized with centrosome signals. In addition, the proximity ligation in situ assay was performed to detect the complex formation in centrosome. Our experiments clearly showed that Myc-tagged RBM8A and Flag-tagged MAGOH formed a complex in centrosome. GFP-tagged PLK1 also co-localized with Myc-RBM8A. Our results show that RBM8A-MAGOH complex is required for M-phase progression via direct localization to centrosome rather than indirect effect.

Inhibition of mTORC2 but not mTORC1 up-regulates E-cadherin expression and inhibits cell motility by blocking HIF-2α expression in human renal cell carcinoma.

PURPOSE: Molecular targeted drugs, such as mTORC1 inhibitors, have been clinically popularized for advanced renal cell carcinoma treatment but metastasis is still a serious concern. mTORC2 has several important functions, including HIF-2α activation in malignant cells. HIF-2α suppresses E-cadherin expression, which is associated with tumor invasion and metastasis. We investigated whether mTORC2 regulates E-cadherin expression and controls cell motility during HIF-2α down-regulation in renal cell carcinoma cells. MATERIALS AND METHODS: We used PP242, a dual inhibitor of mTORC1/mTORC2 and the mTORC1 specific inhibitor rapamycin. E-cadherin expression in 786-O cells was examined using real-time polymerase chain reaction, Western blot and immunocytochemical staining. Cell motility was analyzed by time-lapse microscopy and wound healing assay. RESULTS: High E-cadherin expression was found in RCC4/VHL cells but low levels were found in VHL defective RCC4 and 786-O cells. HIF-2α expression was suppressed only in RCC4/VHL cells. In 786-O cells HIF-2α inhibition induced by the dual mTORC1/C2 inhibitor PP242 (0.05 to 0.5 µmol/L) resulted in a dose dependent increase in E-cadherin expression and the restored E-cadherin was localized at cell-to-cell junctions. Treatment with the mTORC1 inhibitor rapamycin resulted in no significant change. The migration of PP242 treated cells was significantly suppressed compared with those treated with rapamycin. CONCLUSIONS: Results show that mTORC2 might regulate E-cadherin expression and suppress cell motility by controlling the mTORC2-HIF-2α signaling pathway. The dual inhibitor of mTORC1/C2 as a cadherin regulatory agent may be a novel therapeutic strategy with tumoricidal agents for advanced renal cell carcinoma.

Greater potency of darbepoetin-α than erythropoietin in suppression of serum hepcidin-25 and utilization of iron for erythropoiesis in hemodialysis patients.

BACKGROUND: The potency of darbepoetin-α (DPO-α) to improve anemia in hemodialysis (HD) patients is greater than that of recombinant human erythropoietin (rHuEPO). DESIGN AND METHODS: To assess the potency of DPO-α to mobilize iron from body stores in comparison with rHuEPO in HD patients without apparent inflammation or infection, serum iron, transferrin saturation (TSAT), ferritin, and hepcidin-25 were measured serially. This study included (i) a long-term crossover study for 3 yr to compare the effects of the two erythropoiesis-stimulating agents (ESA) on serum iron, TSAT, and ferritin, and (ii) a short-term crossover study for 8 wk to examine their effects on serum hepcidin-25 in HD patients. RESULTS: The long-term crossover study demonstrated that the change of ESA from rHuEPO to DPO-α significantly decreased serum ferritin while serum iron and TSAT remained unchanged, while DPO-α as well as rHuEPO maintained hemoglobin level in the target range between 10.0 and 11.0 g/dL. Furthermore, in the short-term crossover study, area under the percent suppression of serum hepcidin-25 time curve for the first 7 d during the DPO-α treatment period was significantly greater than that during the rHuEPO period (348.0 ± 92.4 vs. 178.4 ± 131.5%.day P = 0.030). The greater suppression of hepcidin-25 by DPO-α may facilitate iron mobilization, resulting in diminution of body iron stores without any significant effect on serum iron utilizable for erythropoiesis. CONCLUSION: This study demonstrated that DPO-α has a greater advantage than rHuEPO in that it facilitates iron mobilization from body stores into bone marrow to induce effective erythropoiesis and thus could protect against possible harmful effects caused by excessive iron stores in the body.

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.

Identification of a novel mutation in the HAMP gene that causes non-detectable hepcidin molecules in a Japanese male patient with juvenile hemochromatosis.

Hepcidin is an iron-regulatory hepatic peptide hormone encoded by the HAMP gene that downregulates iron export from enterocytes and macrophages into the blood plasma. In this study, we identified a novel mutation in the HAMP gene of a 58-year-old Japanese male patient with hemochromatosis. By direct sequencing of the five hereditary hemochromatosis-related genes, HFE, HAMP, HJV, TFR2, and SLC40A1, the previously unreported p.R75X mutation was identified, and the patient was found to be homozygous for the mutation. No other potentially pathogenic mutations were detected. In an LC-MS/MS analysis, hepcidin molecules were not detected in the patient's serum or urine. These results indicate that the p.R75X mutation causes iron overload by impairing the hepcidin system.

Down-regulation of hepcidin resulting from long-term treatment with an anti-IL-6 receptor antibody (tocilizumab) improves anemia of inflammation in multicentric Castleman disease.

Dysregulated production of hepcidin is implicated in anemia of inflammation, whereas interleukin-6 (IL-6) is a major inducer of hepcidin production. Overproduction of IL-6 is responsible for pathogenesis of multicentric Castleman disease (MCD), a rare lymphoproliferative disorder accompanied by systemic inflammatory responses and anemia. In this study, we investigated the roles of hepcidin and IL-6 in anemia of inflammation and the long-term effects of anti-IL-6 receptor antibody (tocilizumab) treatment on serum hepcidin and iron-related parameters in MCD patients. We found that tocilizumab treatment resulted in a rapid reduction of serum hepcidin-25 in 5 of 6 MCD patients. Long-term reductions, accompanied by progressive normalization of iron-related parameters and symptom improvement, were observed in 9 of 9 cases 1.5, 3, 6, and 12 months after the start of tocilizumab treatment. In in vitro experiments, IL-6-induced up-regulation of hepcidin mRNA in hepatoma cell lines was completely inhibited by tocilizumab but increased in the presence of patients' sera. Our results suggest that, although multiple factors affect serum hepcidin levels, IL-6 plays an essential role in the induction of hepcidin in MCD. This accounts for the long-term ameliorative effect of IL-6 blockage with tocilizumab on anemia by inhibiting hepcidin production in MCD patients.

Serum hepcidin-25 levels predict the progression of renal anemia in patients with non-dialysis chronic kidney disease.

BACKGROUND: Hepcidin is associated with iron-restricted erythropoiesis. A previous cross-sectional study showed that serum hepcidin-25 levels are negatively associated with the hemoglobin concentration in non-dialysis chronic kidney disease (CKD) patients with sufficient iron stores. This longitudinal study aimed at ascertaining the association between hepcidin-25 levels and the progression of renal anemia. METHODS: We selected 335 non-dialysis CKD patients who showed hemoglobin concentrations >10 g/dL and who were not receiving erythropoiesis-stimulating agent (ESA) therapy, from among the subjects of our previous study, who had been recruited between February and June 2007 in a previous study. The primary outcome was the start of the ESA therapy or hemoglobin concentrations remaining below 10 g/dL for >3 months, by 31 December 2010. The patients were classified into high- and low-ferritin groups depending on their median ferritin levels. The Cox proportional hazard model with restricted cubic spline curve analysis was used to determine the association between hepcidin-25 levels and the outcome for each group. RESULTS: The hepcidin-25 level was a significant predictor both for the high-ferritin group (P = 0.04, linearity = 0.02) and for the low-ferritin group (P = 0.04, linearity P = 0.02). The spline curve for the high-ferritin group showed that higher hepcidin-25 levels had a high log-relative hazard. CONCLUSIONS: Higher hepcidin-25 levels predict the progression of anemia in non-dialysis CKD patients with sufficient iron stores, indicating the involvement of hepcidin in the progression of anemia in non-dialysis CKD patients.