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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., (© 2019 S. Karger AG, Basel.)

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.

Continuous erythropoietin receptor activator (CERA) and darbepoetin-α (DA) might differently affect iron metabolism and erythropoiesis in patients on hemodialysis (HD). This prospective study examined a cohort of patients on HD who had received either intravenous CERA every 2 or 4 weeks (N = 25) or DA once each week (N = 47). Blood was sampled before HD sessions on days 0, 2, 4, 7 and 14, and on days 0, 3, 5, 7 and 14 from patients who were injected with ESA at the beginning and end of the dialysis week, respectively. Changes in factors indicating erythropoiesis and biomarkers of iron metabolism were examined. Hemoglobin levels were maintained in the target range between 10.0 and 11.0 g/dL and ferritin levels at baseline and during the study period were similar between the DA and CERA groups. Levels of hepcidin 25 decreased from days 2-3 to day 5 and returned to the baseline at day 7 in the DA group, whereas those and transferrin saturation were serially suppressed from days 2-3 to day 14 in the CERA group. Levels of soluble transferrin receptor and reticulocyte counts were significantly elevated from days 4-5 to day 14 by CERA. Both DA and CERA stabilized erythropoiesis, but CERA might mobilize iron from body stores more effectively than DA in patients on HD., (© 2015 International Society for Apheresis, Japanese Society for Apheresis, and Japanese Society for Dialysis Therapy.)

We examined the spatial distribution of the velocity distribution function of Fe atoms in a conventional dc magnetron sputtering source by laser-induced fluorescence (LIF) imaging spectroscopy. By measuring the Doppler broadening of the excitation spectrum of LIF, we evaluated the velocity distribution function of Fe at many positions in the discharge space. By calculating the first- and second-order moments of the velocity distribution function, we obtained two-dimensional maps of the average velocity and the effective temperature in the r-z plane of the cylindrically symmetric magnetron discharge. The map of the average velocity clearly indicates that Fe atoms have fast velocity in the region adjacent to the target at a low discharge pressure such as 3 mTorr, while at a high gas pressure such as 20 mTorr, the average velocity of Fe atoms is almost zero in the entire discharge space. On the other hand, it has been found from the map of the effective temperature that the velocity distribution function observed at 3 mTorr has a broad width corresponding to approximately 8×104 K in the bright plasma near the target. [ABSTRACT FROM AUTHOR]