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de Jong MF, Nemeth E, Rawee P, Bramham K, Eisenga MF. Anemia in Pregnancy With CKD. Kidney Int Rep 2024; 9:1183-1197. [PMID: 38707831 PMCID: PMC11069017 DOI: 10.1016/j.ekir.2024.01.015] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Revised: 12/05/2023] [Accepted: 01/08/2024] [Indexed: 05/07/2024] Open
Abstract
Chronic kidney disease (CKD), anemia, and iron deficiency are global health issues affecting individuals in both high-income and low-income countries. In pregnancy, both CKD and iron deficiency anemia increase the risk of adverse maternal and neonatal outcomes, including increased maternal morbidity and mortality, stillbirth, perinatal death, preterm birth, and low birthweight. However, it is unknown to which extent iron deficiency anemia contributes to adverse outcomes in CKD pregnancy. Furthermore, little is known regarding the prevalence, pathophysiology, and treatment of iron deficiency and anemia in pregnant women with CKD. Therefore, there are many unanswered questions regarding optimal management with oral or i.v. iron and recombinant human erythropoietin (rhEPO) in these women. In this review, we present a short overview of the (patho)physiology of anemia in healthy pregnancy and in people living with CKD. We present an evaluation of the literature on iron deficiency, anemia, and nutritional deficits in pregnant women with CKD; and we evaluate current knowledge gaps. Finally, we propose research priorities regarding anemia in pregnant women with CKD.
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Affiliation(s)
- Margriet F.C. de Jong
- Department of Internal Medicine, Division of Nephrology, University Medical Center Groningen, The Netherlands
| | - Elizabeta Nemeth
- Department of Medicine, University of California, Los Angeles, California, USA
| | - Pien Rawee
- Department of Internal Medicine, Division of Nephrology, University Medical Center Groningen, The Netherlands
| | - Kate Bramham
- Department of Women and Children’s Health, King’s College London, London, UK
| | - Michele F. Eisenga
- Department of Internal Medicine, Division of Nephrology, University Medical Center Groningen, The Netherlands
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Helman SL, Wilkins SJ, Chan JCJ, Hartel G, Wallace DF, Anderson GJ, Frazer DM. A Decrease in Maternal Iron Levels Is the Predominant Factor Suppressing Hepcidin during Pregnancy in Mice. Int J Mol Sci 2023; 24:14379. [PMID: 37762679 PMCID: PMC10532249 DOI: 10.3390/ijms241814379] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Revised: 09/17/2023] [Accepted: 09/19/2023] [Indexed: 09/29/2023] Open
Abstract
In order to supply adequate iron during pregnancy, the levels of the iron regulatory hormone hepcidin in the maternal circulation are suppressed, thereby increasing dietary iron absorption and storage iron release. Whether this decrease in maternal hepcidin is caused by changes in factors known to regulate hepcidin expression, or by other unidentified pregnancy factors, is not known. To investigate this, we examined iron parameters during pregnancy in mice. We observed that hepatic iron stores and transferrin saturation, both established regulators of hepcidin production, were decreased in mid and late pregnancy in normal and iron loaded dams, indicating an increase in iron utilization. This can be explained by a significant increase in maternal erythropoiesis, a known suppressor of hepcidin production, by mid-pregnancy, as indicated by an elevation in circulating erythropoietin and an increase in spleen size and splenic iron uptake. Iron utilization increased further in late pregnancy due to elevated fetal iron demand. By increasing maternal iron levels in late gestation, we were able to stimulate the expression of the gene encoding hepcidin, suggesting that the iron status of the mother is the predominant factor influencing hepcidin levels during pregnancy. Our data indicate that pregnancy-induced hepcidin suppression likely occurs because of reductions in maternal iron reserves due to increased iron requirements, which predominantly reflect stimulated erythropoiesis in mid-gestation and increased fetal iron requirements in late gestation, and that there is no need to invoke other factors, including novel pregnancy factor(s), to explain these changes.
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Affiliation(s)
- Sheridan L. Helman
- Molecular Nutrition Laboratory, QIMR Berghofer Medical Research Institute, Herston, QLD 4006, Australia; (S.L.H.); (J.C.J.C.)
| | - Sarah J. Wilkins
- Iron Metabolism Laboratory, QIMR Berghofer Medical Research Institute, Herston, QLD 4006, Australia (G.J.A.)
| | - Jennifer C. J. Chan
- Molecular Nutrition Laboratory, QIMR Berghofer Medical Research Institute, Herston, QLD 4006, Australia; (S.L.H.); (J.C.J.C.)
| | - Gunter Hartel
- Statistics Unit, QIMR Berghofer Medical Research Institute, Herston, QLD 4006, Australia;
- School of Public Health, The University of Queensland, Herston, QLD 4006, Australia
- School of Nursing, Queensland University of Technology, Kelvin Grove, QLD 4059, Australia
| | - Daniel F. Wallace
- School of Biomedical Sciences and Centre for Genomics and Personalised Health, Queensland University of Technology, Kelvin Grove, Brisbane, QLD 4059, Australia;
| | - Gregory J. Anderson
- Iron Metabolism Laboratory, QIMR Berghofer Medical Research Institute, Herston, QLD 4006, Australia (G.J.A.)
| | - David M. Frazer
- Molecular Nutrition Laboratory, QIMR Berghofer Medical Research Institute, Herston, QLD 4006, Australia; (S.L.H.); (J.C.J.C.)
- School of Biomedical Sciences, Queensland University of Technology, Gardens Point, QLD 4000, Australia
- School of Biomedical Sciences, The University of Queensland, St. Lucia, QLD 4067, Australia
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Sangkhae V, Fisher AL, Ganz T, Nemeth E. Iron Homeostasis During Pregnancy: Maternal, Placental, and Fetal Regulatory Mechanisms. Annu Rev Nutr 2023; 43:279-300. [PMID: 37253681 PMCID: PMC10723031 DOI: 10.1146/annurev-nutr-061021-030404] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Pregnancy entails a large negative balance of iron, an essential micronutrient. During pregnancy, iron requirements increase substantially to support both maternal red blood cell expansion and the development of the placenta and fetus. As insufficient iron has long been linked to adverse pregnancy outcomes, universal iron supplementation is common practice before and during pregnancy. However, in high-resource countries with iron fortification of staple foods and increased red meat consumption, the effects of too much iron supplementation during pregnancy have become a concern because iron excess has also been linked to adverse pregnancy outcomes. In this review, we address physiologic iron homeostasis of the mother, placenta, and fetus and discuss perturbations in iron homeostasis that result in pathological pregnancy. As many mechanistic regulatory systems have been deduced from animal models, we also discuss the principles learned from these models and how these may apply to human pregnancy.
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Affiliation(s)
- Veena Sangkhae
- Center for Iron Disorders, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California, USA;
| | - Allison L Fisher
- Endocrine Unit and Nephrology Division, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Tomas Ganz
- Center for Iron Disorders, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California, USA;
| | - Elizabeta Nemeth
- Center for Iron Disorders, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California, USA;
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Olivera J, Zhang V, Nemeth E, Ganz T. Erythroferrone exacerbates iron overload and ineffective extramedullary erythropoiesis in a mouse model of β-thalassemia. Blood Adv 2023; 7:3339-3349. [PMID: 36995275 PMCID: PMC10345853 DOI: 10.1182/bloodadvances.2022009307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 03/08/2023] [Accepted: 03/29/2023] [Indexed: 03/31/2023] Open
Abstract
β-thalassemia is characterized by chronic hepcidin suppression and iron overload, even in patients who have not undergone transfusion. The HbbTh3/+ (Th3/+) mouse model of nontransfusion-dependent β-thalassemia (NTDBT) partially recapitulates the human phenotype but lacks chronic hepcidin suppression, progressive iron accumulation into adulthood, or the interindividual variation of the rate of iron loading observed in patients. Erythroferrone (ERFE) is an erythroid regulator that suppresses hepcidin during increased erythropoiesis. ERFE concentrations in the sera of patients with NTDBT correlate negatively with hepcidin levels but vary over a broad range, possibly explaining the variability of iron overload in patients. To analyze the effect of high ERFE concentrations on hepcidin and iron overload in NTDBT, we crossed Th3/+ mice with erythroid ERFE-overexpressing transgenic mice. Th3/ERFE-transgenic mice suffered high perinatal mortality, but embryos at E18.5 showed similar viability, appearance, and anemia effects as Th3/+ mice. Compared with Th3/+ littermates, adult Th3/ERFE mice had similarly severe anemia but manifested greater suppression of serum hepcidin and increased iron accumulation in the liver, kidney, and spleen. The Th3/ERFE mice had much higher concentrations of serum ERFE than either parental strain, a finding attributable to both a higher number of erythroblasts and higher production of ERFE by each erythroblast.Th3/+ and Th3/ERFE mice had similar red blood cell count and shortened erythrocyte lifespan, but Th3/ERFE mice had an increased number of erythroid precursors in their larger spleens, indicative of aggravated ineffective extramedullary erythropoiesis. Thus, high ERFE concentrations increase the severity of nontransfusional iron overload and ineffective erythropoiesis in thalassemic mice but do not substantially affect anemia or hemolysis.
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Affiliation(s)
- Joseph Olivera
- Department of Medicine, David Geffen School of Medicine, UCLA, Los Angeles, CA
| | - Vida Zhang
- Department of Medicine, David Geffen School of Medicine, UCLA, Los Angeles, CA
| | - Elizabeta Nemeth
- Department of Medicine, David Geffen School of Medicine, UCLA, Los Angeles, CA
| | - Tomas Ganz
- Department of Medicine, David Geffen School of Medicine, UCLA, Los Angeles, CA
- Department of Pathology, David Geffen School of Medicine, UCLA, Los Angeles, CA
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Delaney KM, Barad A, Castillo LF, Hasund CM, Guillet R, Pressman EK, Katzman PJ, Ganz T, Nemeth E, O'Brien KO. Placental Erythroferrone and Erythropoietin mRNA Expression is not Associated with Maternal or Neonatal Iron Status in Adolescents Carrying Singletons and Adult Women Carrying Multiples. J Nutr 2023; 153:1950-1958. [PMID: 37253412 PMCID: PMC10375499 DOI: 10.1016/j.tjnut.2023.05.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2023] [Revised: 04/27/2023] [Accepted: 05/26/2023] [Indexed: 06/01/2023] Open
Abstract
BACKGROUND The iron regulatory hormones erythroferrone (ERFE), erythropoietin (EPO), and hepcidin, and the cargo receptor nuclear receptor coactivator 4 (NCOA4) are expressed in the placenta. However, determinants of placental expression of these proteins and their associations with maternal or neonatal iron status are unknown. OBJECTIVES To characterize expression of placental ERFE, EPO, and NCOA4 mRNA in placentae from newborns at increased risk of iron deficiency and to evaluate these in relation to maternal and neonatal iron status and regulatory hormones. METHODS Placentae were collected from 114 neonates born to adolescents carrying singletons (14-18 y) and 110 neonates born to 54 adults (20-46 y) carrying multiples. Placental EPO, ERFE, and NCOA4 mRNA expression were measured by RT-qPCR and compared with maternal and neonatal iron status indicators (SF, sTfR, total body iron, serum iron) and hormones. RESULTS Placental ERFE, EPO, and NCOA4 mRNA were detected in all placentae delivered between 25 and 42 wk of gestation. Relationships between placental ERFE and EPO differed by cohort. In the multiples cohort, placental EPO and ERFE were positively correlated (P = 0.004), but only a positive trend (P = 0.08) was evident in the adolescents. Placental EPO and ERFE were not associated with maternal or neonatal iron status markers or hormones in either cohort. Placental NCOA4 was not associated with placental EPO or ERFE in either cohort but was negatively associated with maternal SF (P = 0.03) in the multiples cohort and positively associated with neonatal sTfR (P = 0.009) in the adolescents. CONCLUSIONS The human placenta expresses ERFE, EPO, and NCOA4 mRNA as early as 25 wk of gestation. Placental expression of ERFE and EPO transcripts was not associated with maternal or neonatal iron status. Greater placental NCOA4 transcript expression was evident in women and newborns with poor iron status (lower SF and higher sTfR, respectively). Further research is needed to characterize the roles of these proteins in the human placenta. TRIAL REGISTRATION NUMBER These clinical trials were registered at clinicaltrials.gov as NCT01019902 (https://clinicaltrials.gov/ct2/show/NCT01019902) and NCT01582802 (https://clinicaltrials.gov/ct2/show/NCT01582802).
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Affiliation(s)
- Katherine M Delaney
- Division of Nutritional Sciences, Cornell University, Ithaca, NY, United States
| | - Alexa Barad
- Division of Nutritional Sciences, Cornell University, Ithaca, NY, United States
| | - Luisa F Castillo
- Division of Nutritional Sciences, Cornell University, Ithaca, NY, United States
| | - Chloe M Hasund
- Division of Nutritional Sciences, Cornell University, Ithaca, NY, United States
| | - Ronnie Guillet
- Department of Pediatrics Division of Neonatology, University of Rochester School of Medicine, Rochester, NY, United States
| | - Eva K Pressman
- Department of Obstetrics and Gynecology, University of Rochester School of Medicine, Rochester, NY, United States
| | - Philip J Katzman
- Department of Pathology and Clinical Laboratory Medicine, University of Rochester School of Medicine, Rochester, NY, United States
| | - Tomas Ganz
- David Geffen School of Medicine, Center for Iron Disorders, University of California Los Angeles, Los Angeles, CA, United States
| | - Elizabeta Nemeth
- David Geffen School of Medicine, Center for Iron Disorders, University of California Los Angeles, Los Angeles, CA, United States
| | - Kimberly O O'Brien
- Division of Nutritional Sciences, Cornell University, Ithaca, NY, United States.
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Assessing erythroferrone and iron homeostasis in preeclamptic and normotensive pregnancies: A retrospective study. Placenta 2023; 133:10-18. [PMID: 36696784 DOI: 10.1016/j.placenta.2023.01.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 01/15/2023] [Accepted: 01/18/2023] [Indexed: 01/21/2023]
Abstract
INTRODUCTION Preeclampsia (PE) is a pregnancy-related disorder associated with maternal hypertension and placental dysfunction. A significant micronutrient during pregnancy is iron, which is important in cellular functions. While iron absorption increases in pregnancy, little is known about the exact mechanisms regulating maternal iron levels and transfer through the placenta in normal and complicated pregnancies. METHODS In this retrospective study, we investigated the regulation of maternal and placental iron availability and storage, in normotensive and pregnancies complicated by early- or late-onset PE. Methods used were analysis of clinical records, ELISA analysis on plasma samples, immunofluorescent and Prussian Blue analysis on placenta biopsies. RESULTS Focusing on erythroferrone (ERFE) as a new marker and hormonal regulator of iron, our results demonstrated altered maternal ERFE levels in PE. We are the first to report the expression of ERFE in trophoblasts and indicate its lower levels in early-onset PE placentas. These changes were associated with lower placental transferrin receptor 1 (TfR1) in syncytiotrophoblasts in both early- and late-onset PE. In addition, maternal plasma ERFE levels were elevated in both early- and late-onset PE and hepcidin levels reduced in early-onset PE. Unaltered maternal plasma IL-6 levels suggest mechanism other than inflammation being involved in altered iron regulation in PE pregnancy. DISCUSSION Our data supports a deregulation in maternal iron bioavailability in early- and late-onset PE vs normotensive pregnancies. The exact role of placental ERFE in regulating maternal-placental-fetal iron transport axis requires further investigation.
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