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Seng NWP, Barco JB, Wong MHL, Lim KX, Peh WM, Ng CT, Cushway T, Foo FJ, Koh FHX. Hypophosphatemia related to intravenous iron therapy with ferric carboxymaltose: A case series. Transfus Med 2023; 33:503-508. [PMID: 37263781 DOI: 10.1111/tme.12980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2022] [Revised: 01/28/2023] [Accepted: 04/13/2023] [Indexed: 06/03/2023]
Abstract
OBJECTIVES This case series would like to highlight hypophosphatemia related to ferric carboxymaltose and its adverse clinical consequences. BACKGROUND Intravenous iron supplementation is a good alternative to oral iron replacement in iron deficiency anaemia due to its ability to correct iron deficit with minimal infusions without incurring the gastrointestinal side effects of oral iron replacement. Ferric carboxymaltose is one common formula for intravenous iron supplementation. However, an increasingly recognised adverse side-effect of intravenous ferric carboxymaltose is hypophosphatemia. There has been increasing reports and studies highlighting hypophosphatemia related to intra-venous iron therapy. Though initially thought to be transient and asymptomatic, recent studies have shown that persistent hypophosphatemia in iron therapy can result in debilitating disease including myopathy, fractures and osteomalacia. METHODS A retrospective analysis of all patients who had ferric carboxymaltose was performed. RESULTS We highlight 3 cases where hyposphatemia affected the clinical outcomes. CONCLUSION With the increased use of IV iron it is important to be aware of the high potential for hypophosphatemia secondary to ferric carboxymaltose.
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Affiliation(s)
- Nigel Wei-Peng Seng
- Ministry of Health Holdings, Singapore, Singapore
- Sengkang General Hospital, Singapore, Singapore
| | | | | | | | | | | | - Tim Cushway
- The Iron Suites Medical Centre, Singapore, Singapore
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2
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Muras-Szwedziak K, Pawłowicz-Szlarska E, Nowicki M. Effect of intravenous iron on endogenous erythropoietin and FGF-23 secretion in patients with chronic kidney disease. Ren Fail 2023; 45:2164305. [PMID: 36688811 PMCID: PMC9873275 DOI: 10.1080/0886022x.2022.2164305] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
INTRODUCTION It has been observed that intravenous iron administration may suppress endogenous production of erythropoietin (EPO). We postulate that this effect may be mediated by increased FGF-23 secretion. AIM OF THE STUDY To evaluate the short-term effect of intravenous iron sucrose administration on endogenous EPO secretion in patients with chronic kidney disease (CKD). MATERIALS AND METHODS The cohort comprised 35 nondialysis patients with CKD stages 3-5. All received 100 mg of intravenous iron (III)-hydroxide sucrose complex daily for five consecutive days. Plasma EPO, iFGF-23, cFGF-23, PTH, bone alkaline phosphatase (BAP), phosphorus (PO4), calcium (Ca), and high-sensitive C-reactive protein (CRP) were measured before, and two hours after, the first and third iron infusions, and after completing iron therapy. RESULTS EPO concentration at the end of iron treatment was significantly lower than two hours after the first iron infusion (p = 0.0003) and before the third dose (p = 0.0006) (12.6 [10.2, 41.4] mIU/mL. vs. 30.9 [15.9, 54.2] mIU/mL and 33.4 [15.4, 56.7] mIU/mL, respectively). Conversely, plasma iFGF-23 was significantly higher before the third dose (61.1 [18.6, 420.1 4] pg/mL; p = 0.025) and after the course of treatment (92.1 [28.4, 878.1] pg/mL; p = 0.004) compared to pretreatment value (48.4 [16.2, 420] pg/mL). cFGF-23 concentration was significantly lower than baseline after the first iron dose (491.8 [257.7, 1086.3] vs. 339.2 [75.4, 951.2] RU/mL; p = 0.005) and after treatment (398.7 [90.4, 1022.3] RU/mL; p = 0.025). No significant linear correlation was found between changes in plasma EPO and FGF-23. CONCLUSIONS Although intravenous iron therapy causes parallel increase of FGF-23 and supression of endogenous EPO, these two effects seem to be independent.
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Affiliation(s)
- Katarzyna Muras-Szwedziak
- Department of Nephrology, Hypertension and Kidney Transplantation, Medical University of Lodz, Lodz, Poland
| | - Ewa Pawłowicz-Szlarska
- Department of Nephrology, Hypertension and Kidney Transplantation, Medical University of Lodz, Lodz, Poland
| | - Michał Nowicki
- Department of Nephrology, Hypertension and Kidney Transplantation, Medical University of Lodz, Lodz, Poland,CONTACT Michał Nowicki Central University Hospital, Medical University of Lodz, Pomorska 251, Lodz, 92-213, Poland
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3
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Transferrin analysis in wistar rats plasma: Towards an electrochemical point-of-care approach for the screening of alcohol abuse. Microchem J 2022. [DOI: 10.1016/j.microc.2022.107738] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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Koljonen L, Enlund-Cerullo M, Hauta-alus H, Holmlund-Suila E, Valkama S, Rosendahl J, Andersson S, Pekkinen M, Mäkitie O. Phosphate Concentrations and Modifying Factors in Healthy Children From 12 to 24 Months of Age. J Clin Endocrinol Metab 2021; 106:2865-2875. [PMID: 34214153 PMCID: PMC8475199 DOI: 10.1210/clinem/dgab495] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Indexed: 12/12/2022]
Abstract
CONTEXT Phosphate homeostasis and its modifiers in early childhood are inadequately characterized. OBJECTIVE To determine physiological plasma phosphate concentration and modifying factors in healthy infants at 12 to 24 months of age. DESIGN This study included 525 healthy infants (53% girls), who participated in a randomized vitamin D intervention trial and received daily vitamin D3 supplementation of either 10 or 30 μg from age 2 weeks to 24 months. Biochemical parameters were measured at 12 and 24 months. Dietary phosphate intake was determined at 12 months. MAIN OUTCOME MEASURES Plasma phosphate concentrations at 12 and 24 months of age. RESULTS Mean (SD) phosphate concentration decreased from 12 months (1.9 ± 0.15 mmol/L) to 24 months (1.6 ± 0.17 mmol/L) of age (P < 0.001 for repeated measurements). When adjusted by covariates, such as body size, creatinine, serum 25-hydroxyvitamin D, intact and C-terminal fibroblast growth factor 23, mean plasma phosphate was higher in boys than girls during follow-up (P = 0.019). Phosphate concentrations were similar in the vitamin D intervention groups (P > 0.472 for all). Plasma iron was associated positively with plasma phosphate at both time points (B, 0.006 and 0.005; 95% CI, 0.004-0.009 and 0.002-0.008; P < 0.001 at both time points, respectively). At 24 months of age, the main modifier of phosphate concentration was plasma creatinine (B, 0.007; 95% CI 0.003-0.011, P < 0.001). CONCLUSION Plasma phosphate concentration decreased from age 12 to 24 months. In infants and toddlers, the strongest plasma phosphate modifiers were sex, iron, and creatinine, whereas vitamin D supplementation did not modify phosphate concentrations.
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Affiliation(s)
- Laura Koljonen
- Folkhälsan Research Center, 00290 Helsinki, Finland
- Research Program for Clinical and Molecular Metabolism, Faculty of Medicine, University of Helsinki, 00014 Helsinki, Finland
| | - Maria Enlund-Cerullo
- Folkhälsan Research Center, 00290 Helsinki, Finland
- Research Program for Clinical and Molecular Metabolism, Faculty of Medicine, University of Helsinki, 00014 Helsinki, Finland
- Children’s Hospital, Pediatric Research Center, University of Helsinki and Helsinki University Hospital, 00014 Helsinki, Finland
| | - Helena Hauta-alus
- Research Program for Clinical and Molecular Metabolism, Faculty of Medicine, University of Helsinki, 00014 Helsinki, Finland
- Children’s Hospital, Pediatric Research Center, University of Helsinki and Helsinki University Hospital, 00014 Helsinki, Finland
- National Institute for Health and Welfare (THL), 00271 Helsinki, Finland
- PEDEGO Research Unit, MRC Oulu, Oulu University Hospital and University of Oulu, 90014 Oulu,Finland
| | - Elisa Holmlund-Suila
- Research Program for Clinical and Molecular Metabolism, Faculty of Medicine, University of Helsinki, 00014 Helsinki, Finland
- Children’s Hospital, Pediatric Research Center, University of Helsinki and Helsinki University Hospital, 00014 Helsinki, Finland
| | - Saara Valkama
- Research Program for Clinical and Molecular Metabolism, Faculty of Medicine, University of Helsinki, 00014 Helsinki, Finland
- Children’s Hospital, Pediatric Research Center, University of Helsinki and Helsinki University Hospital, 00014 Helsinki, Finland
| | - Jenni Rosendahl
- Research Program for Clinical and Molecular Metabolism, Faculty of Medicine, University of Helsinki, 00014 Helsinki, Finland
- Children’s Hospital, Pediatric Research Center, University of Helsinki and Helsinki University Hospital, 00014 Helsinki, Finland
| | - Sture Andersson
- Children’s Hospital, Pediatric Research Center, University of Helsinki and Helsinki University Hospital, 00014 Helsinki, Finland
| | - Minna Pekkinen
- Folkhälsan Research Center, 00290 Helsinki, Finland
- Research Program for Clinical and Molecular Metabolism, Faculty of Medicine, University of Helsinki, 00014 Helsinki, Finland
- Children’s Hospital, Pediatric Research Center, University of Helsinki and Helsinki University Hospital, 00014 Helsinki, Finland
| | - Outi Mäkitie
- Folkhälsan Research Center, 00290 Helsinki, Finland
- Research Program for Clinical and Molecular Metabolism, Faculty of Medicine, University of Helsinki, 00014 Helsinki, Finland
- Children’s Hospital, Pediatric Research Center, University of Helsinki and Helsinki University Hospital, 00014 Helsinki, Finland
- Department of Molecular Medicine and Surgery, Karolinska Institutet, and Clinical Genetics, Karolinska University Hospital, 17176 Stockholm, Sweden
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Lee KH, Ho Y, Tarng DC. Iron Therapy in Chronic Kidney Disease: Days of Future Past. Int J Mol Sci 2021; 22:1008. [PMID: 33498292 PMCID: PMC7863960 DOI: 10.3390/ijms22031008] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 01/10/2021] [Accepted: 01/18/2021] [Indexed: 02/06/2023] Open
Abstract
Anemia affects millions of patients with chronic kidney disease (CKD) and prompt iron supplementation can lead to reductions in the required dose of erythropoiesis-stimulating agents, thereby reducing medical costs. Oral and intravenous (IV) traditional iron preparations are considered far from ideal, primarily due to gastrointestinal intolerability and the potential risk of infusion reactions, respectively. Fortunately, the emergence of novel iron replacement therapies has engendered a paradigm shift in the treatment of iron deficiency anemia in patients with CKD. For example, oral ferric citrate is an efficacious and safe phosphate binder that increases iron stores to maintain hemoglobin levels. Additional benefits include reductions in fibroblast growth factor 23 levels and the activation of 1,25 dihydroxyvitamin D. The new-generation IV iron preparations ferumoxytol, iron isomaltoside 1000, and ferric carboxymaltose are characterized by a reduced risk of infusion reactions and are clinically well tolerated as a rapid high-dose infusion. In patients undergoing hemodialysis (HD), ferric pyrophosphate citrate (FPC) administered through dialysate enables the replacement of ongoing uremic and HD-related iron loss. FPC transports iron directly to transferrin, bypassing the reticuloendothelial system and avoiding iron sequestration. Moreover, this paper summarizes recent advancements of hypoxia-inducible factor prolyl hydroxylase inhibitors and future perspectives in renal anemia management.
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Affiliation(s)
- Kuo-Hua Lee
- Division of Nephrology, Department of Medicine, Taipei Veterans General Hospital, Taipei 11217, Taiwan; (K.-H.L.); (Y.H.)
- Institute of Clinical Medicine, National Yang-Ming University, Taipei 11217, Taiwan
- Center for Intelligent Drug Systems and Smart Bio-devices (IDSB), Hsinchu 300, Taiwan
| | - Yang Ho
- Division of Nephrology, Department of Medicine, Taipei Veterans General Hospital, Taipei 11217, Taiwan; (K.-H.L.); (Y.H.)
| | - Der-Cherng Tarng
- Division of Nephrology, Department of Medicine, Taipei Veterans General Hospital, Taipei 11217, Taiwan; (K.-H.L.); (Y.H.)
- Institute of Clinical Medicine, National Yang-Ming University, Taipei 11217, Taiwan
- Center for Intelligent Drug Systems and Smart Bio-devices (IDSB), Hsinchu 300, Taiwan
- Department of Biological Science and Technology, College of Biological Science and Technology, National Chiao Tung University, Hsinchu 300, Taiwan
- Department and Institute of Physiology, National Yang-Ming University, Taipei 11217, Taiwan
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6
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Schaefer B, Tobiasch M, Viveiros A, Tilg H, Kennedy NA, Wolf M, Zoller H. Hypophosphataemia after treatment of iron deficiency with intravenous ferric carboxymaltose or iron isomaltoside-a systematic review and meta-analysis. Br J Clin Pharmacol 2020; 87:2256-2273. [PMID: 33188534 PMCID: PMC8247006 DOI: 10.1111/bcp.14643] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 10/27/2020] [Accepted: 11/03/2020] [Indexed: 12/21/2022] Open
Abstract
Aims Hypophosphataemia is an increasingly recognized side‐effect of ferric carboxymaltose (FCM) and possibly iron isomaltoside/ferric derisomaltose (IIM), which are used to treat iron deficiency. The aim of this study was to determine frequency, severity, duration and risk factors of incident hypophosphataemia after treatment with FCM and IIM. Methods A systematic literature search for articles indexed in EMBASE, PubMed and Web of Science in years 2005–2020 was carried out using the search terms ‘ferric carboxymaltose’ OR ‘iron isomaltoside’. Prospective clinical trials reporting outcomes on hypophosphataemia rate, mean nadir serum phosphate and/or change in mean serum phosphate from baseline were selected. Hypophosphataemia rate and severity were compared for studies on IIM vs. FCM after stratification for chronic kidney disease. Meta‐regression analysis was used to investigate risk factors for hypophosphataemia. Results Across the 42 clinical trials included in the meta‐analysis, FCM induced a significantly higher incidence of hypophosphataemia than IIM (47%, 95% CI 36–58% vs. 4%, 95% CI 2–5%), and significantly greater mean decreases in serum phosphate (0.40 vs. 0.06 mmol/L). Hypophosphataemia persisted at the end of the study periods (maximum 3 months) in up to 45% of patients treated with FCM. Meta‐regression analysis identified low baseline serum ferritin and transferrin saturation, and normal kidney function as significant predictors of hypophosphataemia. Conclusion FCM is associated with a high risk of hypophosphataemia, which does not resolve for at least 3 months in a large proportion of affected patients. More severe iron deficiency and normal kidney function are risk factors for hypophosphataemia.
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Affiliation(s)
- Benedikt Schaefer
- Department of Medicine I, Gastroenterology, Hepatology and Endocrinology, Medical University of Innsbruck, Innsbruck, Austria.,Christian Doppler Laboratory of Iron and Phosphate Biology, Medical University of Innsbruck, Innsbruck, Austria
| | - Moritz Tobiasch
- Department of Medicine, University Teaching Hospital of Hall in Tirol, Hall, Austria
| | - André Viveiros
- Department of Medicine I, Gastroenterology, Hepatology and Endocrinology, Medical University of Innsbruck, Innsbruck, Austria.,Christian Doppler Laboratory of Iron and Phosphate Biology, Medical University of Innsbruck, Innsbruck, Austria
| | - Herbert Tilg
- Department of Medicine I, Gastroenterology, Hepatology and Endocrinology, Medical University of Innsbruck, Innsbruck, Austria
| | - Nicholas A Kennedy
- IBD Pharmacogenetics, University of Exeter, Exeter, UK.,Gastrointestinal Unit, Western General Hospital, Edinburgh, UK
| | - Myles Wolf
- Department of Medicine, Division of Nephrology, and Duke Clinical Research Institute, Duke University School of Medicine, Durham, NC, USA
| | - Heinz Zoller
- Department of Medicine I, Gastroenterology, Hepatology and Endocrinology, Medical University of Innsbruck, Innsbruck, Austria.,Christian Doppler Laboratory of Iron and Phosphate Biology, Medical University of Innsbruck, Innsbruck, Austria
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7
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Mace ML, Olgaard K, Lewin E. New Aspects of the Kidney in the Regulation of Fibroblast Growth Factor 23 (FGF23) and Mineral Homeostasis. Int J Mol Sci 2020; 21:E8810. [PMID: 33233840 PMCID: PMC7699902 DOI: 10.3390/ijms21228810] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 11/16/2020] [Accepted: 11/19/2020] [Indexed: 02/07/2023] Open
Abstract
The bone-derived hormone fibroblast growth factor 23 (FGF23) acts in concert with parathyroid hormone (PTH) and the active vitamin D metabolite calcitriol in the regulation of calcium (Ca) and phosphate (P) homeostasis. More factors are being identified to regulate FGF23 levels and the endocrine loops between the three hormones. The present review summarizes the complex regulation of FGF23 and the disturbed FGF23/Klotho system in chronic kidney disease (CKD). In addition to the reduced ability of the injured kidney to regulate plasma levels of FGF23, several CKD-related factors have been shown to stimulate FGF23 production. The high circulating FGF23 levels have detrimental effects on erythropoiesis, the cardio-vascular system and the immune system, all contributing to the disturbed system biology in CKD. Moreover, new factors secreted by the injured kidney and the uremic calcified vasculature play a role in the mineral and bone disorder in CKD and create a vicious pathological crosstalk.
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Affiliation(s)
- Maria L. Mace
- Department of Nephrology, Rigshospitalet, University of Copenhagen, 2100 Copenhagen, Denmark; (K.O.); (E.L.)
| | - Klaus Olgaard
- Department of Nephrology, Rigshospitalet, University of Copenhagen, 2100 Copenhagen, Denmark; (K.O.); (E.L.)
| | - Ewa Lewin
- Department of Nephrology, Rigshospitalet, University of Copenhagen, 2100 Copenhagen, Denmark; (K.O.); (E.L.)
- Department of Nephrology, Herlev Hospital, University of Copenhagen, 2730 Herlev, Denmark
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8
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Cavdar Z, Oktan MA, Ural C, Kocak A, Calisir M, Heybeli C, Yildiz S, Ozbal S, Arslan S, Ergur BU, Yilmaz O, Cavdar C. Alpha lipoic acid attenuates iron induced oxidative acute kidney injury in rats. Biotech Histochem 2020; 96:409-417. [PMID: 32921159 DOI: 10.1080/10520295.2020.1812001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Iron has been implicated in oxidative tissue injury owing to its ability to generate reactive oxygen species (ROS). We investigated the reno-protective effects of alpha lipoic acid (ALA) by investigating its effects on the kidney isoform of NADPH oxidase (Nox4) and the specific signaling pathways, p38 MAPK and PI3K/Akt, which participate in apoptosis and survival, respectively. We established four groups of seven rats: control, 100 mg/kg ALA, 80 mg/kg iron sucrose (IS) and IS + ALA. IS and ALA were injected intravenously and rats were sacrificied after 6 h. The mRNA expression of the subunits of NADPH oxidase, Nox4 and p22phox; tumor necrosis factor-alpha (TNF-α); and kidney injury molecule-1 (KIM-1) were measured using quantitative real time polymerase chain reaction (qRT-PCR). Active caspase-3 protein expression was evaluated by immunostaining. Also, p38 MAPK and PI3K/Akt signaling pathways were analyzed using western blot. ALA suppressed the mRNA expression of Nox4, p22phox, TNF-α and KIM-1. Active caspase-3 protein expression induced by IS was decreased by ALA. ALA also suppressed p38 MAPK and activated the PI3K/Akt signaling pathway following IS administration. We found that ALA may be an effective strategy for preventing oxidative acute kidney injury caused by IS.
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Affiliation(s)
- Zahide Cavdar
- Department of Molecular Medicine, Health Sciences Institute, Dokuz Eylul University, Izmir, Turkey
| | - Mehmet Asi Oktan
- Department of Nephrology, Faculty of Medicine, Dokuz Eylul University, Izmir, Turkey
| | - Cemre Ural
- Department of Molecular Medicine, Health Sciences Institute, Dokuz Eylul University, Izmir, Turkey
| | - Ayse Kocak
- Department of Molecular Medicine, Health Sciences Institute, Dokuz Eylul University, Izmir, Turkey
| | - Meryem Calisir
- Department of Laboratory Animal Science, Health Sciences Institute, Dokuz Eylul University, Izmir, Turkey
| | - Cihan Heybeli
- Department of Nephrology, Faculty of Medicine, Dokuz Eylul University, Izmir, Turkey
| | - Serkan Yildiz
- Department of Nephrology, Faculty of Medicine, Dokuz Eylul University, Izmir, Turkey
| | - Seda Ozbal
- Department of Histology and Embryology, Faculty of Medicine, Dokuz Eylul University, Izmir, Turkey
| | - Sevki Arslan
- Department of Biology, Faculty of Science, Pamukkale University, Denizli, Turkey
| | - Bekir Ugur Ergur
- Department of Histology and Embryology, Faculty of Medicine, Dokuz Eylul University, Izmir, Turkey
| | - Osman Yilmaz
- Department of Laboratory Animal Science, Health Sciences Institute, Dokuz Eylul University, Izmir, Turkey
| | - Caner Cavdar
- Department of Nephrology, Faculty of Medicine, Dokuz Eylul University, Izmir, Turkey
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9
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Noonan ML, Clinkenbeard EL, Ni P, Swallow EA, Tippen SP, Agoro R, Allen MR, White KE. Erythropoietin and a hypoxia-inducible factor prolyl hydroxylase inhibitor (HIF-PHDi) lowers FGF23 in a model of chronic kidney disease (CKD). Physiol Rep 2020; 8:e14434. [PMID: 32476270 PMCID: PMC7261757 DOI: 10.14814/phy2.14434] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 04/10/2020] [Accepted: 04/13/2020] [Indexed: 12/19/2022] Open
Abstract
Iron-deficiency anemia is a potent stimulator of the phosphaturic hormone Fibroblast growth factor-23 (FGF23). Anemia, elevated FGF23, and elevated serum phosphate are significant mortality risk factors for patients with chronic kidney disease (CKD). However, the contribution of anemia to overall circulating FGF23 levels in CKD is not understood. Our goal was to investigate the normalization of iron handling in a CKD model using the erythropoiesis stimulating agents (ESAs) Erythropoietin (EPO) and the hypoxia-inducible factor prolyl hydroxylase inhibitor (HIF-PHDi) FG-4592, on the production of, and outcomes associated with, changes in bioactive, intact FGF23 ("iFGF23"). Our hypothesis was that rescuing the prevailing anemia in a model of CKD would reduce circulating FGF23. Wild-type mice were fed an adenine-containing diet to induce CKD, then injected with EPO or FG-4592. The mice with CKD were anemic, and EPO improved red blood cell indices, whereas FG-4592 increased serum EPO and bone marrow erythroferrone (Erfe), and decreased liver ferritin, bone morphogenic protein-6 (Bmp-6), and hepcidin mRNAs. In the mice with CKD, iFGF23 was markedly elevated in control mice but was attenuated by >70% after delivery of either ESA, with no changes in serum phosphate. ESA treatment also reduced renal fibrosis markers, as well as increased Cyp27b1 and reduced Cyp24a1 mRNA expression. Thus, improvement of iron utilization in a CKD model using EPO and a HIF-PHDi significantly reduced iFGF23, demonstrating that anemia is a primary driver of FGF23, and that management of iron utilization in patients with CKD may translate to modifiable outcomes in mineral metabolism.
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Affiliation(s)
- Megan L. Noonan
- Department of Medical and Molecular GeneticsIndiana University School of MedicineIndianapolisINUSA
| | - Erica L. Clinkenbeard
- Department of Medical and Molecular GeneticsIndiana University School of MedicineIndianapolisINUSA
| | - Pu Ni
- Department of Medical and Molecular GeneticsIndiana University School of MedicineIndianapolisINUSA
| | - Elizabeth A. Swallow
- Department of AnatomyCell Biology, and PhysiologyIndiana University School of MedicineIndianapolisINUSA
| | - Samantha P. Tippen
- Department of Medical and Molecular GeneticsIndiana University School of MedicineIndianapolisINUSA
- Department of AnatomyCell Biology, and PhysiologyIndiana University School of MedicineIndianapolisINUSA
| | - Rafiou Agoro
- Department of Medical and Molecular GeneticsIndiana University School of MedicineIndianapolisINUSA
| | - Matthew R. Allen
- Department of AnatomyCell Biology, and PhysiologyIndiana University School of MedicineIndianapolisINUSA
- Department of MedicineDivision of NephrologyIndiana University School of MedicineIndianapolisINUSA
| | - Kenneth E. White
- Department of Medical and Molecular GeneticsIndiana University School of MedicineIndianapolisINUSA
- Department of MedicineDivision of NephrologyIndiana University School of MedicineIndianapolisINUSA
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10
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FGF23 at the crossroads of phosphate, iron economy and erythropoiesis. Nat Rev Nephrol 2019; 16:7-19. [PMID: 31519999 DOI: 10.1038/s41581-019-0189-5] [Citation(s) in RCA: 154] [Impact Index Per Article: 30.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/24/2019] [Indexed: 12/20/2022]
Abstract
Fibroblast growth factor 23 (FGF23) was initially characterized as an important regulator of phosphate and calcium homeostasis. New research advances demonstrate that FGF23 is also linked to iron economy, inflammation and erythropoiesis. These advances have been fuelled, in part, by the serendipitous development of two distinct FGF23 assays that can substitute for invasive bone biopsies to infer the activity of the three main steps of FGF23 regulation in bone: transcription, post-translational modification and peptide cleavage. This 'liquid bone biopsy for FGF23 dynamics' enables large-scale longitudinal studies of FGF23 regulation that would otherwise be impossible in humans. The balance between FGF23 production, post-translational modification and cleavage is maintained or perturbed in different hereditary monogenic conditions and in acquired conditions that mimic these genetic disorders, including iron deficiency, inflammation, treatment with ferric carboxymaltose and chronic kidney disease. Looking ahead, a deeper understanding of the relationships between FGF23 regulation, iron homeostasis and erythropoiesis can be leveraged to devise novel therapeutic targets for treatment of anaemia and states of FGF23 excess, including chronic kidney disease.
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11
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Nordholm A, Egstrand S, Gravesen E, Mace ML, Morevati M, Olgaard K, Lewin E. Circadian rhythm of activin A and related parameters of mineral metabolism in normal and uremic rats. Pflugers Arch 2019; 471:1079-1094. [PMID: 31236663 PMCID: PMC6614158 DOI: 10.1007/s00424-019-02291-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 06/04/2019] [Accepted: 06/05/2019] [Indexed: 12/11/2022]
Abstract
Activin A is a new fascinating player in chronic kidney disease-mineral and bone disorder (CKD-MBD), which is implicated in progressive renal disease, vascular calcification, and osteodystrophy. Plasma activin A rises early in the progression of renal disease. Disruption of circadian rhythms is related to increased risk of several diseases and circadian rhythms are observed in mineral homeostasis, bone parameters, and plasma levels of phosphate and PTH. Therefore, we examined the circadian rhythm of activin A and CKD-MBD-related parameters (phosphate, PTH, FGF23, and klotho) in healthy controls and CKD rats (5/6 nephrectomy) on high-, standard- and low-dietary phosphate contents as well as during fasting conditions. Plasma activin A exhibited circadian rhythmicity in healthy control rats with fourfold higher values at acrophase compared with nadir. The rhythm was obliterated in CKD. Activin A was higher in CKD rats compared with controls when measured at daytime but not significantly when measured at evening/nighttime, stressing the importance of time-specific reference intervals when interpreting plasma values. Plasma phosphate, PTH, and FGF23 all showed circadian rhythms in control rats, which were abolished or disrupted in CKD. Plasma klotho did not show circadian rhythm. Thus, the present investigation shows, for the first time, circadian rhythm of plasma activin A. The rhythmicity is severely disturbed by CKD and is associated with disturbed rhythms of phosphate and phosphate-regulating hormones PTH and FGF23, indicating that disturbed circadian rhythmicity is an important feature of CKD-MBD.
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Affiliation(s)
- Anders Nordholm
- Nephrological Department, Herlev Hospital, University of Copenhagen, 2730, Herlev, Denmark.,Nephrological Department, Rigshospitalet, University of Copenhagen, 2100, Copenhagen, Denmark
| | - Søren Egstrand
- Nephrological Department, Herlev Hospital, University of Copenhagen, 2730, Herlev, Denmark.,Nephrological Department, Rigshospitalet, University of Copenhagen, 2100, Copenhagen, Denmark
| | - Eva Gravesen
- Nephrological Department, Rigshospitalet, University of Copenhagen, 2100, Copenhagen, Denmark
| | - Maria L Mace
- Nephrological Department, Herlev Hospital, University of Copenhagen, 2730, Herlev, Denmark.,Nephrological Department, Rigshospitalet, University of Copenhagen, 2100, Copenhagen, Denmark
| | - Marya Morevati
- Nephrological Department, Rigshospitalet, University of Copenhagen, 2100, Copenhagen, Denmark
| | - Klaus Olgaard
- Nephrological Department, Rigshospitalet, University of Copenhagen, 2100, Copenhagen, Denmark
| | - Ewa Lewin
- Nephrological Department, Herlev Hospital, University of Copenhagen, 2730, Herlev, Denmark. .,Nephrological Department, Rigshospitalet, University of Copenhagen, 2100, Copenhagen, Denmark.
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12
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Cardiac hypertrophy in chronic kidney disease—role of Aldosterone and FGF23. RENAL REPLACEMENT THERAPY 2018. [DOI: 10.1186/s41100-018-0152-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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13
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Effect of inhibition of CBP-coactivated β-catenin-mediated Wnt signalling in uremic rats with vascular calcifications. PLoS One 2018; 13:e0201936. [PMID: 30075015 PMCID: PMC6075782 DOI: 10.1371/journal.pone.0201936] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2018] [Accepted: 07/24/2018] [Indexed: 11/30/2022] Open
Abstract
Uremic vascular calcification is a regulated cell-mediated process wherein cells in the arterial wall transdifferentiate to actively calcifying cells resulting in a process resembling bone formation. Wnt signalling is established as a major driver for vessel formation and maturation and for embryonic bone formation, and disturbed Wnt signalling might play a role in vascular calcification. ICG-001 is a small molecule Wnt inhibitor that specifically targets the coactivator CREB binding protein (CBP)/β-catenin-mediated signalling. In the present investigation we examined the effect of ICG-001 on vascular calcification in uremic rats. Uremic vascular calcification was induced in adult male rats by 5/6-nephrectomy, high phosphate diet and alfacalcidol. The presence of uremic vascular calcification in the aorta was associated with induction of gene expression of the Wnt target gene and marker of proliferation, cyclinD1; the mediator of canonical Wnt signalling, β-catenin and the matricellular proteins, fibronectin and periostin. Furthermore, genes from fibrosis-related pathways, TGF-β and activin A, as well as factors related to epithelial-mesenchymal transition, snail1 and vimentin were induced. ICG-001 treatment had significant effects on gene expression in kidney and aorta from healthy rats. These effects were however limited in uremic rats, and treatment with ICG-001 did not reduce the Ca-content of the uremic vasculature.
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14
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Urbina T, Belkhir R, Rossi G, Carbonnel F, Pavy S, Collins M, Mariette X, Seror R. Iron Supplementation-Induced Phosphaturic Osteomalacia: FGF23 is the Culprit. J Bone Miner Res 2018; 33:540-542. [PMID: 29281120 DOI: 10.1002/jbmr.3369] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Accepted: 12/19/2017] [Indexed: 12/13/2022]
Affiliation(s)
- Tomas Urbina
- Assistance Publique-Hopitaux de Paris, Hôpitaux Universitaires Paris-Sud, Department of Rheumatology, Le Kremlin Bicêtre, France.,Université Paris-Sud; INSERM U1184, Le Kremlin Bicêtre, France
| | - Rakiba Belkhir
- Assistance Publique-Hopitaux de Paris, Hôpitaux Universitaires Paris-Sud, Department of Rheumatology, Le Kremlin Bicêtre, France.,Université Paris-Sud; INSERM U1184, Le Kremlin Bicêtre, France
| | - Geoffrey Rossi
- Assistance Publique-Hopitaux de Paris, Hôpitaux Universitaires Paris-Sud, Department of Rheumatology, Le Kremlin Bicêtre, France.,Université Paris-Sud; INSERM U1184, Le Kremlin Bicêtre, France
| | - Franck Carbonnel
- Assistance Publique-Hopitaux de Paris, Hôpitaux Universitaires Paris-Sud, Department of Rheumatology, Le Kremlin Bicêtre, France
| | - Stephan Pavy
- Assistance Publique-Hopitaux de Paris, Hôpitaux Universitaires Paris-Sud, Department of Rheumatology, Le Kremlin Bicêtre, France.,Université Paris-Sud; INSERM U1184, Le Kremlin Bicêtre, France
| | - Michael Collins
- Assistance Publique-Hopitaux de Paris, Hôpitaux Universitaires Paris-Sud, Department of Rheumatology, Le Kremlin Bicêtre, France
| | - Xavier Mariette
- Assistance Publique-Hopitaux de Paris, Hôpitaux Universitaires Paris-Sud, Department of Rheumatology, Le Kremlin Bicêtre, France.,Université Paris-Sud; INSERM U1184, Le Kremlin Bicêtre, France
| | - Raphaèle Seror
- Assistance Publique-Hopitaux de Paris, Hôpitaux Universitaires Paris-Sud, Department of Rheumatology, Le Kremlin Bicêtre, France.,Université Paris-Sud; INSERM U1184, Le Kremlin Bicêtre, France
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15
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Exogenous BMP7 in aortae of rats with chronic uremia ameliorates expression of profibrotic genes, but does not reverse established vascular calcification. PLoS One 2018; 13:e0190820. [PMID: 29304096 PMCID: PMC5755916 DOI: 10.1371/journal.pone.0190820] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Accepted: 12/20/2017] [Indexed: 12/24/2022] Open
Abstract
Hyperphosphatemia and vascular calcification are frequent complications of chronic renal failure and bone morphogenetic protein 7 (BMP7) has been shown to protect against development of vascular calcification in uremia. The present investigation examined the potential reversibility of established uremic vascular calcification by treatment of uremic rats with BMP7. A control model of isogenic transplantation of a calcified aorta from uremic rats into healthy littermates examined whether normalization of the uremic environment reversed vascular calcification. Uremia and vascular calcification were induced in rats by 5/6 nephrectomy, high phosphate diet and alfacalcidol treatment. After 14 weeks severe vascular calcification was present and rats were allocated to BMP7, vehicle or aorta transplantation. BMP7 treatment caused a significant decrease of plasma phosphate to 1.56 ± 0.17 mmol/L vs 2.06 ± 0.34 mmol/L in the vehicle group even in the setting of uremia and high phosphate diet. Uremia and alfacalcidol resulted in an increase in aortic expression of genes related to fibrosis, osteogenic transformation and extracellular matrix calcification, and the BMP7 treatment resulted in a decrease in the expression of profibrotic genes. The total Ca-content of the aorta was however unchanged both in the abdominal aorta: 1.9 ± 0.6 μg/mg tissue in the vehicle group vs 2.2 ± 0.6 μg/mg tissue in the BMP7 group and in the thoracic aorta: 71 ± 27 μg/mg tissue in the vehicle group vs 54 ± 18 μg/mg tissue in the BMP7 group. Likewise, normalization of the uremic environment by aorta transplantation had no effect on the Ca-content of the calcified aorta: 16.3 ± 0.6 μg/mg tissue pre-transplantation vs 15.9 ± 2.3 μg/mg tissue post-transplantation. Aortic expression of genes directly linked to extracellular matrix calcification was not affected by BMP7 treatment, which hypothetically might explain persistent high Ca-content in established vascular calcification. The present results highlight the importance of preventing the development of vascular calcification in chronic kidney disease. Once established, vascular calcification persists even in the setting when hyperphosphatemia or the uremic milieu is abolished.
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16
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Kidney fibroblast growth factor 23 does not contribute to elevation of its circulating levels in uremia. Kidney Int 2017; 92:165-178. [PMID: 28341272 DOI: 10.1016/j.kint.2017.01.015] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Revised: 12/21/2016] [Accepted: 01/05/2017] [Indexed: 02/08/2023]
Abstract
Fibroblast growth factor 23 (FGF23) secreted by osteocytes is a circulating factor essential for phosphate homeostasis. High plasma FGF23 levels are associated with cardiovascular complications and mortality. Increases of plasma FGF23 in uremia antedate high levels of phosphate, suggesting a disrupted feedback regulatory loop or an extra-skeletal source of this phosphatonin. Since induction of FGF23 expression in injured organs has been reported we decided to examine the regulation of FGF23 gene and protein expressions in the kidney and whether kidney-derived FGF23 contributes to the high plasma levels of FGF23 in uremia. FGF23 mRNA was not detected in normal kidneys, but was clearly demonstrated in injured kidneys, already after four hours in obstructive nephropathy and at 8 weeks in the remnant kidney of 5/6 nephrectomized rats. No renal extraction was found in uremic rats in contrast to normal rats. Removal of the remnant kidney had no effect on plasma FGF23 levels. Well-known regulators of FGF23 expression in bone, such as parathyroid hormone, calcitriol, and inhibition of the FGF receptor by PD173074, had no impact on kidney expression of FGF23. Thus, the only direct contribution of the injured kidney to circulating FGF23 levels in uremia appears to be reduced renal extraction of bone-derived FGF23. Kidney-derived FGF23 does not generate high plasma FGF23 levels in uremia and is regulated differently than the corresponding regulation of FGF23 gene expression in bone.
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17
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Effects of lanthanum carbonate and calcium carbonate on fibroblast growth factor 23 and hepcidin levels in chronic hemodialysis patients. Clin Exp Nephrol 2016; 21:908-916. [PMID: 27928636 DOI: 10.1007/s10157-016-1362-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Accepted: 11/23/2016] [Indexed: 01/16/2023]
Abstract
BACKGROUND Phosphate binders have an impact on fibroblast growth factor 23 (FGF23); however, the effect of phosphate binders on serum hepcidin has not been explored. We conducted a 24-week multicenter randomized controlled trial to investigate the effects of lanthanum carbonate or calcium carbonate monotherapy on serum phosphate, FGF23, and hepcidin levels in chronic hemodialysis patients. METHODS Forty-six patients were recruited, and daily dietary phosphorus was controlled between 600-800 mg. Serum calcium, phosphate, albumin, alkaline phosphatase (ALP), FGF23, intact parathyroid hormone (iPTH), hepcidin, high-sensitivity CRP (hsCRP), 25(OH)D, 1,25(OH)2D, fetuin-A, and osteopontin were checked as scheduled. RESULTS Twenty-five patients completed the study. Mean serum FGF23 level was significantly decreased after a 24-week treatment with lanthanum (8677.5 ± 7490.0 vs. 4692.8 ± 5348.3 pg/mL, p = 0.013, n = 13), but not with calcium (n = 12). The reduction of serum hepcidin in lanthanum group was positively correlated with the decrement of serum phosphate (r = 0.631, p = 0.021) and serum hsCRP (r = 0.670, p = 0.012) levels, respectively. Serum ALP, iPTH, vitamin D, fetuin-A, and osteopontin revealed no significant inter- or intragroup differences. CONCLUSIONS In summary, a decrease in serum FGF23 levels and a trend of decline in hepcidin levels were observed only in lanthanum group.
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18
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Tan SJ, Satake S, Smith ER, Toussaint ND, Hewitson TD, Holt SG. Parenteral iron polymaltose changes i:c-terminal FGF23 ratios in iron deficiency, but not in dialysis patients. Eur J Clin Nutr 2016; 71:180-184. [DOI: 10.1038/ejcn.2016.217] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Revised: 09/22/2016] [Accepted: 09/27/2016] [Indexed: 12/17/2022]
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19
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Macher S, Drexler C, Lindenau I, Sareban N, Schlenke P, Amrein K. High-dose intravenously administered iron versus orally administered iron in blood donors with iron deficiency: study protocol for a randomised, controlled trial. Trials 2016; 17:527. [PMID: 27793204 PMCID: PMC5084417 DOI: 10.1186/s13063-016-1648-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2016] [Accepted: 10/07/2016] [Indexed: 01/01/2023] Open
Abstract
Background About 2–3 % of the population participates in blood donation programmes. Each whole blood donation or ten apheresis donations cause a loss of 200–250 mg of iron. As a result, one of the most common risks of regular blood donors is iron deficiency. Although this has been known for decades, in most countries, iron status is currently not assessed or treated in this population. Premenopausal women are particularly affected, as they have lower iron reserves and higher daily requirements. Besides anaemia, iron deficiency may lead to fatigue and impaired cognitive and physical performance. Current iron preparations for intravenous administration are well tolerated and allow for application of large doses up to 1 g in one visit. Our hypothesis is that in blood donors with iron deficiency, intravenously administered iron is more efficient and as safe as oral iron supplementation. Since anaemia is one of the most frequent reasons for permanent or intermittent donor deferral, maintaining an iron-replete donor pool may help to prevent shortages in blood supply and to avoid iron deficiency-related comorbidities. Methods/design In this randomised clinical trial we include male and female blood donors aged ≥18 and ≤65 years with a ferritin value of ≤30 ng/ml. Stratified by gender, participants are randomized with a web-based randomisation tool in a 1:1 ratio to either 1 g of intravenously administered ferric carboxymaltose or 10 g of iron fumarate supplements at one to two daily doses of 100 mg each. Eight to 12 weeks after the first visit, iron status, blood count and symptoms are assessed in both groups. The primary endpoint is the difference in transferrin saturation (%) following the intervention between both groups. Secondary endpoints include other parameters of iron metabolism and red blood cell count, the number of patients with drug-related adverse events, and subjective symptoms including those of the restless legs syndrome, quality of life, and fatigue. Discussion Iron supplementation administered intravenously in non-anaemic but iron-deficient blood donors could represent an effective strategy to protect blood donors from comorbidities related with iron deficiency and therefore improve blood donor wellbeing. Furthermore, iron supplementation will help to maintain an iron-replete blood donor pool. Trial registration EudraCT: 2013-000327-14, Clinical Trials Identifier: NCT01787526. Registered on 6 February 2013. Electronic supplementary material The online version of this article (doi:10.1186/s13063-016-1648-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Susanne Macher
- Department of Blood Group Serology and Transfusion Medicine, Medical University of Graz, Graz, Austria
| | - Camilla Drexler
- Department of Blood Group Serology and Transfusion Medicine, Medical University of Graz, Graz, Austria
| | - Ines Lindenau
- Department of Blood Group Serology and Transfusion Medicine, Medical University of Graz, Graz, Austria.,Department of Internal Medicine, Division of Endocrinology and Diabetology, Medical University of Graz, Auenbruggerplatz 15, 8036, Graz, Austria
| | - Nazanin Sareban
- Department of Blood Group Serology and Transfusion Medicine, Medical University of Graz, Graz, Austria
| | - Peter Schlenke
- Department of Blood Group Serology and Transfusion Medicine, Medical University of Graz, Graz, Austria
| | - Karin Amrein
- Department of Internal Medicine, Division of Endocrinology and Diabetology, Medical University of Graz, Auenbruggerplatz 15, 8036, Graz, Austria.
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20
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Neyra JA, Moe OW, Hu MC. Fibroblast growth factor 23 and acute kidney injury. Pediatr Nephrol 2015; 30:1909-18. [PMID: 25480729 PMCID: PMC4458234 DOI: 10.1007/s00467-014-3006-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Revised: 11/03/2014] [Accepted: 11/04/2014] [Indexed: 02/07/2023]
Abstract
Fibroblast growth factor 23 (FGF23), which is produced in bone, participates in the maintenance of phosphate metabolism and can serve as a biomarker for adverse cardiovascular outcomes in patients with chronic kidney disease and end-stage renal disease. Circulating FGF23 rapidly increases after acute kidney injury (AKI), preceding other known markers such as neutrophil gelatinase-associated lipocalin and serum creatinine. The increase in FGF23 in AKI appears to be independent of parathyroid hormone, vitamin D signaling pathways, and dietary phosphate. The potential mechanisms include: (1) increased production of FGF23 in the bone by yet-to-be-identified factors; (2) ectopic production of FGF23 by injured renal tubules; and (3) decreased renal clearance of circulating FGF23. Circulating FGF23 determined by intact FGF23 enzyme-linked immunosorbent assay (ELISA) is a more reliable biomarker of AKI than FGF23 C-terminal ELISA (a mixed readout of C-terminal fragment and intact FGF23). Given that FGF23 can be ectopically expressed in differentiated renal tubules and iron modulates FGF23 metabolism, an effect of iron on FGF23 expression in renal tubules is conceivable but remains to be confirmed. More clinical and experimental studies are required to validate the use of circulating FGF23 as a biomarker for the early identification of AKI and prediction of short- and long-term adverse outcomes post-AKI. More importantly, the biologic effect of increased FGF23 in AKI needs to be defined.
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Affiliation(s)
- Javier A Neyra
- Department of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX, 75390-885, USA
| | - Orson W Moe
- Department of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX, 75390-885, USA
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Charles and Jane Pak Center for Mineral Metabolism and Clinical Research, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX, 75390-885, USA
| | - Ming Chang Hu
- Department of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX, 75390-885, USA.
- Charles and Jane Pak Center for Mineral Metabolism and Clinical Research, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX, 75390-885, USA.
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Eser B, Yayar O, Buyukbakkal M, Erdogan B, Ercan Z, Merhametsiz O, haspulat A, Oğuz EG, Dogan İ, Canbakan B, Ayli MD. Fibroblast growth factor is associated to left ventricular mass index, anemia and low values of transferrin saturation. Nefrologia 2015; 35:465-72. [DOI: 10.1016/j.nefro.2015.06.025] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Revised: 06/16/2015] [Accepted: 06/17/2015] [Indexed: 01/09/2023] Open
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Abstract
Phosphate is essential for growth and maintenance of the skeleton and for generating high-energy phosphate compounds. Evolutionary adaptation to high dietary phosphorous in humans and other terrestrial vertebrates involves regulated mechanisms assuring the efficient renal elimination of excess phosphate. These mechanisms prominently include PTH, FGF23, and Vitamin D, which directly and indirectly regulate phosphate transport. Disordered phosphate homeostasis is associated with pathologies ranging from kidney stones to kidney failure. Chronic kidney disease results in hyperphosphatemia, an elevated calcium×phosphate product with considerable morbidity and mortality, mostly associated with adverse cardiovascular events. This chapter highlights recent findings and insights regarding the hormonal regulation of renal phosphate transport along with imbalances of phosphate balance due to acquired or inherited diseases states.
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23
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Coupling fibroblast growth factor 23 production and cleavage: iron deficiency, rickets, and kidney disease. Curr Opin Nephrol Hypertens 2015; 23:411-9. [PMID: 24867675 DOI: 10.1097/01.mnh.0000447020.74593.6f] [Citation(s) in RCA: 153] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
PURPOSE OF REVIEW High levels of fibroblast growth factor 23 (FGF23) cause the rare disorders of hypophosphatemic rickets and are a risk factor for cardiovascular disease and death in patients with chronic kidney disease (CKD). Despite major advances in understanding FGF23 biology, fundamental aspects of FGF23 regulation in health and in CKD remain mostly unknown. RECENT FINDINGS Autosomal dominant hypophosphatemic rickets (ADHR) is caused by gain-of-function mutations in FGF23 that prevent its proteolytic cleavage, but affected individuals experience a waxing and waning course of phosphate wasting. This led to the discovery that iron deficiency is an environmental trigger that stimulates FGF23 expression and hypophosphatemia in ADHR. Unlike osteocytes in ADHR, normal osteocytes couple increased FGF23 production with commensurately increased FGF23 cleavage to ensure that normal phosphate homeostasis is maintained in the event of iron deficiency. Simultaneous measurement of FGF23 by intact and C-terminal assays supported these breakthroughs by providing minimally invasive insight into FGF23 production and cleavage in bone. These findings also suggest a novel mechanism of FGF23 elevation in patients with CKD, who are often iron deficient and demonstrate increased FGF23 production and decreased FGF23 cleavage, consistent with an acquired state that mimics the molecular pathophysiology of ADHR. SUMMARY Iron deficiency stimulates FGF23 production, but normal osteocytes couple increased FGF23 production with increased cleavage to maintain normal circulating levels of biologically active hormone. These findings uncover a second level of FGF23 regulation within osteocytes, failure of which culminates in elevated levels of biologically active FGF23 in ADHR and perhaps CKD.
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Toblli JE, Angerosa M. Optimizing iron delivery in the management of anemia: patient considerations and the role of ferric carboxymaltose. Drug Des Devel Ther 2014; 8:2475-91. [PMID: 25525337 PMCID: PMC4266270 DOI: 10.2147/dddt.s55499] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
With the challenge of optimizing iron delivery, new intravenous (iv) iron-carbohydrate complexes have been developed in the last few years. A good example of these new compounds is ferric carboxymaltose (FCM), which has recently been approved by the US Food and Drug Administration for the treatment of iron deficiency anemia in adult patients who are intolerant to oral iron or present an unsatisfactory response to oral iron, and in adult patients with non-dialysis-dependent chronic kidney disease (NDD-CKD). FCM is a robust and stable complex similar to ferritin, which minimizes the release of labile iron during administration, allowing higher doses to be administered in a single application and with a favorable cost-effective rate. Cumulative information from randomized, controlled, multicenter trials on a diverse range of indications, including patients with chronic heart failure, postpartum anemia/abnormal uterine bleeding, inflammatory bowel disease, NDD-CKD, and those undergoing hemodialysis, supports the efficacy of FCM for iron replacement in patients with iron deficiency and iron-deficiency anemia. Furthermore, as FCM is a dextran-free iron-carbohydrate complex (which has a very low risk for hypersensitivity reactions) with a small proportion of the reported adverse effects in a large number of subjects who received FCM, it may be considered a safe drug. Therefore, FCM appears as an interesting option to apply high doses of iron as a single infusion in a few minutes in order to obtain the quick replacement of iron stores. The present review on FCM summarizes diverse aspects such as pharmacology characteristics and analyzes trials on the efficacy/safety of FCM versus oral iron and different iv iron compounds in multiple clinical scenarios. Additionally, the information on cost effectiveness and data on change in quality of life are also discussed.
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Affiliation(s)
- Jorge Eduardo Toblli
- Nephrology Section, Department of Internal Medicine, Hospital Alemán, School of Medicine, University of Buenos Aires, Argentina
| | - Margarita Angerosa
- Nephrology Section, Department of Internal Medicine, Hospital Alemán, School of Medicine, University of Buenos Aires, Argentina
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