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Santhakumar S, Edison ES. Molecular insights into placental iron transfer mechanisms and maternofetal regulation. Arch Gynecol Obstet 2024; 309:63-77. [PMID: 37069381 DOI: 10.1007/s00404-023-07032-6] [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: 12/24/2022] [Accepted: 03/28/2023] [Indexed: 04/19/2023]
Abstract
PURPOSE Adequate iron transportation from the mother across the placenta is crucial for fetal growth and establishing sufficient iron stores in neonates at birth. The past decade has marked significant discoveries in iron metabolism with the identification of new players and mechanisms. Immunohistochemical studies rendered valuable data on the localization of substantial iron transporters on placental syncytiotrophoblasts. However, the function and regulation of maternal-placentofetal iron transporters and iron handling is still elusive and requires more attention. METHODS A thorough literature review was conducted to gather information about placental iron transfer, the role of regulators and maintenance of iron homeostasis. RESULTS The role of classical and new players in maternal-fetal iron transport and the regulation in the placenta has been addressed in this review. Animal and human studies have been discussed. The role of placental iron regulation in thalassemia and hemochromatosis pregnancies has been reviewed. CONCLUSIONS The current advances that highlight the mechanisms of placental iron regulation and transport in response to maternal and fetal signals have been presented.
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Affiliation(s)
- Sreenithi Santhakumar
- Department of Haematology, Christian Medical College, Vellore, Tamil Nadu, 632 004, India
- Sree Chitra Tirunal Institute for Medical Sciences & Technology, Kerala, Thiruvananthapuram, India
| | - Eunice S Edison
- Department of Haematology, Christian Medical College, Vellore, Tamil Nadu, 632 004, India.
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2
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Zaugg J, Solenthaler F, Albrecht C. Materno-fetal iron transfer and the emerging role of ferroptosis pathways. Biochem Pharmacol 2022; 202:115141. [PMID: 35700759 DOI: 10.1016/j.bcp.2022.115141] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Revised: 06/03/2022] [Accepted: 06/07/2022] [Indexed: 11/28/2022]
Abstract
A successful pregnancy and the birth of a healthy baby depend to a great extent on the controlled supply of essential nutrients via the placenta. Iron is essential for mitochondrial energy supply and oxygen distribution via the blood. However, its high reactivity requires tightly regulated transport processes. Disturbances of maternal-fetal iron transfer during pregnancy can aggravate or lead to severe pathological consequences for the mother and the fetus with lifelong effects. Furthermore, high intracellular iron levels due to disturbed gestational iron homeostasis have recently been associated with the non-apoptotic cell death pathway called ferroptosis. Therefore, the investigation of transplacental iron transport mechanisms, their physiological regulation and potential risks are of high clinical importance. The present review summarizes the current knowledge on principles and regulatory mechanisms underlying materno-fetal iron transport and gives insight into common pregnancy conditions in which iron homeostasis is disturbed. Moreover, the significance of the newly emerging ferroptosis pathway and its impact on the regulation of placental iron homeostasis, oxidative stress and gestational diseases will be discussed.
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Affiliation(s)
- Jonas Zaugg
- Institute of Biochemistry and Molecular Medicine, Faculty of Medicine, University of Bern, Switzerland; Swiss National Centre of Competence in Research (NCCR) TransCure, University of Bern, Switzerland
| | - Fabia Solenthaler
- Institute of Biochemistry and Molecular Medicine, Faculty of Medicine, University of Bern, Switzerland; Swiss National Centre of Competence in Research (NCCR) TransCure, University of Bern, Switzerland
| | - Christiane Albrecht
- Institute of Biochemistry and Molecular Medicine, Faculty of Medicine, University of Bern, Switzerland; Swiss National Centre of Competence in Research (NCCR) TransCure, University of Bern, Switzerland.
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3
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Differences and Interactions in Placental Manganese and Iron Transfer across an In Vitro Model of Human Villous Trophoblasts. Int J Mol Sci 2022; 23:ijms23063296. [PMID: 35328723 PMCID: PMC8951728 DOI: 10.3390/ijms23063296] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Revised: 03/03/2022] [Accepted: 03/14/2022] [Indexed: 12/10/2022] Open
Abstract
Manganese (Mn) as well as iron (Fe) are essential trace elements (TE) important for the maintenance of physiological functions including fetal development. However, in the case of Mn, evidence suggests that excess levels of intrauterine Mn are associated with adverse pregnancy outcomes. Although Mn is known to cross the placenta, the fundamentals of Mn transfer kinetics and mechanisms are largely unknown. Moreover, exposure to combinations of TEs should be considered in mechanistic transfer studies, in particular for TEs expected to share similar transfer pathways. Here, we performed a mechanistic in vitro study on the placental transfer of Mn across a BeWo b30 trophoblast layer. Our data revealed distinct differences in the placental transfer of Mn and Fe. While placental permeability to Fe showed a clear inverse dose-dependency, Mn transfer was largely independent of the applied doses. Concurrent exposure of Mn and Fe revealed transfer interactions of Fe and Mn, indicating that they share common transfer mechanisms. In general, mRNA and protein expression of discussed transporters like DMT1, TfR, or FPN were only marginally altered in BeWo cells despite the different exposure scenarios highlighting that Mn transfer across the trophoblast layer likely involves a combination of active and passive transport processes.
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4
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Venkata Surekha M, Sujatha T, Gadhiraju S, Kotturu SK, Siva Prasad M, Sarada K, Bhaskar V, Uday Kumar P. Effect of Maternal Iron Deficiency Anaemia on the Expression of Iron Transport Proteins in the Third Trimester Placenta. Fetal Pediatr Pathol 2021; 40:581-596. [PMID: 32096669 DOI: 10.1080/15513815.2020.1725942] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/29/2019] [Accepted: 01/23/2020] [Indexed: 10/24/2022]
Abstract
BackgroundDuring pregnancy, iron is transferred from mother to fetus with placental iron transport proteins (Transferrin receptor, Divalent metal transporter/DMT1, ferroportin/FPN1 and Zyklopen). The aim of the study was to evaluate the effect of maternal iron deficiency anemia on placental iron transporters. Study Design: Two hundred pregnant women, in third trimester of pregnancy were divided into anemic (Hemoglobin/Hb < 11g/dl) and non-anemic groups (Hb ≥ 11 g/dl). After delivery, placental expression of iron transport proteins were studied by immunohistochemistry and by mRNA analysis. Results: Of the 200 subjects, 59% were anemic. All 3 placental proteins showed statistically significant increase in immunohistochemical expression, proportionate to the severity of maternal anemia. The mRNA expression of DMT-1 gene was only significantly elevated in placentas of anemic mothers. Conclusion: Although in our study mRNA expression of only the DMT-1 gene was significantly high, immunohistochemically however all the 3 proteins showed significantly higher expression in placentas of anemic mothers.
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Affiliation(s)
| | - Thathapudi Sujatha
- Pathology and Microbiology Division, National Institute of Nutrition, Hyderabad, India
| | | | | | - Mudili Siva Prasad
- Biochemistry Division, National Institute of Nutrition, Hyderabad, India
| | - K Sarada
- Pathology and Microbiology Division, National Institute of Nutrition, Hyderabad, India
| | - Varanasi Bhaskar
- Statistics Division, National Institute of Nutrition, Hyderabad, India
| | - Putcha Uday Kumar
- Pathology and Microbiology Division, National Institute of Nutrition, Hyderabad, India
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5
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Roberts H, Woodman AG, Baines KJ, Jeyarajah MJ, Bourque SL, Renaud SJ. Maternal Iron Deficiency Alters Trophoblast Differentiation and Placental Development in Rat Pregnancy. Endocrinology 2021; 162:6396887. [PMID: 34647996 PMCID: PMC8559528 DOI: 10.1210/endocr/bqab215] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Indexed: 02/06/2023]
Abstract
Iron deficiency, which occurs when iron demands chronically exceed intake, is prevalent in pregnant women. Iron deficiency during pregnancy poses major risks for the baby, including fetal growth restriction and long-term health complications. The placenta serves as the interface between a pregnant mother and her baby, and it ensures adequate nutrient provisions for the fetus. Thus, maternal iron deficiency may impact fetal growth and development by altering placental function. We used a rat model of diet-induced iron deficiency to investigate changes in placental growth and development. Pregnant Sprague-Dawley rats were fed either a low-iron or iron-replete diet starting 2 weeks before mating. Compared with controls, both maternal and fetal hemoglobin were reduced in dams fed low-iron diets. Iron deficiency decreased fetal liver and body weight, but not brain, heart, or kidney weight. Placental weight was increased in iron deficiency, due primarily to expansion of the placental junctional zone. The stimulatory effect of iron deficiency on junctional zone development was recapitulated in vitro, as exposure of rat trophoblast stem cells to the iron chelator deferoxamine increased differentiation toward junctional zone trophoblast subtypes. Gene expression analysis revealed 464 transcripts changed at least 1.5-fold (P < 0.05) in placentas from iron-deficient dams, including altered expression of genes associated with oxygen transport and lipoprotein metabolism. Expression of genes associated with iron homeostasis was unchanged despite differences in levels of their encoded proteins. Our findings reveal robust changes in placentation during maternal iron deficiency, which could contribute to the increased risk of fetal distress in these pregnancies.
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Affiliation(s)
- Hannah Roberts
- Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, N6A5C1, Canada
| | - Andrew G Woodman
- Department of Anesthesiology & Pain Medicine, University of Alberta, Edmonton, Alberta, T6G2E1, Canada
- Department of Pharmacology, University of Alberta, Edmonton, Alberta, T6G2E1, Canada
- Department of Pediatrics, University of Alberta, Edmonton, Alberta, T6G2E1, Canada
| | - Kelly J Baines
- Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, N6A5C1, Canada
| | - Mariyan J Jeyarajah
- Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, N6A5C1, Canada
| | - Stephane L Bourque
- Department of Anesthesiology & Pain Medicine, University of Alberta, Edmonton, Alberta, T6G2E1, Canada
- Department of Pharmacology, University of Alberta, Edmonton, Alberta, T6G2E1, Canada
- Department of Pediatrics, University of Alberta, Edmonton, Alberta, T6G2E1, Canada
| | - Stephen J Renaud
- Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, N6A5C1, Canada
- Children’s Health Research Institute, Lawson Health Research Institute, London, Ontario, N6C2V5, Canada
- Correspondence: Stephen J. Renaud, PhD, Department of Anatomy and Cell Biology, University of Western Ontario, 1151 Richmond St, London, Ontario, Canada N6A5C1.
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Cross JH, Prentice AM, Cerami C. Hepcidin, Serum Iron, and Transferrin Saturation in Full-Term and Premature Infants during the First Month of Life: A State-of-the-Art Review of Existing Evidence in Humans. Curr Dev Nutr 2020; 4:nzaa104. [PMID: 32793848 PMCID: PMC7413980 DOI: 10.1093/cdn/nzaa104] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 06/04/2020] [Accepted: 06/11/2020] [Indexed: 02/07/2023] Open
Abstract
Neonates regulate iron at birth and in early postnatal life. We reviewed literature from PubMed and Ovid Medline containing data on umbilical cord and venous blood concentrations of hepcidin and iron, and transferrin saturation (TSAT), in human neonates from 0 to 1 mo of age. Data from 59 studies were used to create reference ranges for hepcidin, iron, and TSAT for full-term-birth (FTB) neonates over the first month of life. In FTB neonates, venous hepcidin increases 100% over the first month of life (to reach 61.1 ng/mL; 95% CI: 20.1, 102.0 ng/mL) compared with umbilical cord blood (29.7 ng/mL; 95% CI: 21.1, 38.3 ng/mL). Cord blood has a high concentration of serum iron (28.4 μmol/L; 95% CI: 26.0, 31.1 μmol/L) and levels of TSAT (51.7%; 95% CI: 46.5%, 56.9%). After a short-lived immediate postnatal hypoferremia, iron and TSAT rebounded to approximately half the levels in the cord by the end of the first month. There were insufficient data to formulate reference ranges for preterm neonates.
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Affiliation(s)
- James H Cross
- Epidemiology and Population Health, Medical Research Council Unit The Gambia at the London School of Hygiene & Tropical Medicine, Fajara, Banjul, The Gambia
| | - Andrew M Prentice
- Epidemiology and Population Health, Medical Research Council Unit The Gambia at the London School of Hygiene & Tropical Medicine, Fajara, Banjul, The Gambia
| | - Carla Cerami
- Epidemiology and Population Health, Medical Research Council Unit The Gambia at the London School of Hygiene & Tropical Medicine, Fajara, Banjul, The Gambia
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7
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Li B, He H, Shi W, Hou T. Effect of duck egg white peptide-ferrous chelate on iron bioavailability in vivo and structure characterization. JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE 2019; 99:1834-1841. [PMID: 30255570 DOI: 10.1002/jsfa.9377] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 08/05/2018] [Accepted: 09/17/2018] [Indexed: 05/13/2023]
Abstract
BACKGROUND In order to utilize the industrial by-product 'salted duck egg white' as novel iron additives, the effects of desalted duck egg white peptides-ferrous chelate (DPs-Fe) on the promotion of iron uptake and the structure were investigated. RESULTS Different doses of DPs-Fe were given and iron sulfate (FeSO4 ) was used as a positive control. After three weeks, hemoglobin (Hb), hematocrit (HCT), red blood cells (RBCs), mean corpuscular volume (MCV), serum iron (SI) and serum ferritin (SF) in iron-deficiency anemia (IDA) rats could be significantly (P < 0.05) increased to the normal levels by DPs-Fe. The gene expressions of divalent metal transporter 1 (DMT1), ferroportin 1 (FPN1) and Hepcidin could be regulated by DPs-Fe. Additionally, DPs-Fe was formed during the chelation process and the structure was characterized. Eight crucial iron-chelating peptides of duck egg white peptides (DPs) were identified by HPLC-ESI-MS/MS, such as Pro-Val-Glu-Glu and Arg-Ser-Ser. It indicated that Glu, Asp, Lys, His, Ser, Cys residues might play crucial roles in the chelating of DPs with iron. CONCLUSION DPs-Fe could be a potential iron supplement, and the Glu, Asp, Lys, His played important roles in binding iron and promoting iron uptake. This research expands the understanding of iron uptake by DPs and provides an opportunity for recycling a discarded processing byproduct. © 2018 Society of Chemical Industry.
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Affiliation(s)
- Bo Li
- College of Food Science and Technology, Huazhong Agricultural University, Wuhan, PR China
- Key Laboratory of Environment Correlative Dietology (Huazhong Agricultural University), Ministry of Education, Wuhan, PR China
| | - Hui He
- College of Food Science and Technology, Huazhong Agricultural University, Wuhan, PR China
- Key Laboratory of Environment Correlative Dietology (Huazhong Agricultural University), Ministry of Education, Wuhan, PR China
| | - Wen Shi
- College of Food Science and Technology, Huazhong Agricultural University, Wuhan, PR China
- Key Laboratory of Environment Correlative Dietology (Huazhong Agricultural University), Ministry of Education, Wuhan, PR China
| | - Tao Hou
- College of Food Science and Technology, Huazhong Agricultural University, Wuhan, PR China
- Key Laboratory of Environment Correlative Dietology (Huazhong Agricultural University), Ministry of Education, Wuhan, PR China
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8
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Sangkhae V, Nemeth E. Placental iron transport: The mechanism and regulatory circuits. Free Radic Biol Med 2019; 133:254-261. [PMID: 29981833 PMCID: PMC7059975 DOI: 10.1016/j.freeradbiomed.2018.07.001] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Revised: 06/30/2018] [Accepted: 07/03/2018] [Indexed: 02/06/2023]
Abstract
As the interface between the fetal and maternal circulation, the placenta facilitates both nutrient and waste exchange for the developing fetus. Iron is essential for healthy pregnancy, and transport of iron across the placenta is required for fetal growth and development. Perturbation of this transfer can lead to adverse pregnancy outcomes. Despite its importance, our understanding of how a large amount of iron is transported across placental membranes, how this process is regulated, and which iron transporter proteins function in different placental cells remains rudimentary. Mechanistic studies in mouse models, including placenta-specific deletion or overexpression of iron-related proteins will be essential to make progress. This review summarizes our current understanding about iron transport across the syncytiotrophoblast under physiological conditions and identifies areas for further investigation.
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Affiliation(s)
- Veena Sangkhae
- Center for Iron Disorders, Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, 10833 LeConte Ave, CHS 37-131, Los Angeles, CA 90095, USA.
| | - Elizabeta Nemeth
- Center for Iron Disorders, Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, 10833 LeConte Ave, CHS 37-131, Los Angeles, CA 90095, USA.
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9
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Almeida MPO, Ferro EAV, Briceño MPP, Oliveira MC, Barbosa BF, Silva NM. Susceptibility of human villous (BeWo) and extravillous (HTR-8/SVneo) trophoblast cells to Toxoplasma gondii infection is modulated by intracellular iron availability. Parasitol Res 2019; 118:1559-1572. [PMID: 30796516 DOI: 10.1007/s00436-019-06257-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Accepted: 02/11/2019] [Indexed: 12/20/2022]
Abstract
Congenital toxoplasmosis is a serious health problem that can lead to miscarriage. HTR-8/SVneo is a first trimester extravillous trophoblast, while BeWo is a choriocarcinoma with properties of villous trophoblast cells. In the placenta, iron is taken up from Fe-transferrin through the transferrin receptor being the ion an important nutrient during pregnancy and also for Toxoplasma gondii proliferation. The aim of this study was to evaluate the role of iron in T. gondii proliferation in BeWo and HTR-8/SVneo cells and in human chorionic villous explants. The cells were infected with T. gondii, iron supplemented or deprived by holo-transferrin or deferoxamine, respectively, and parasite proliferation and genes related to iron balance were analyzed. It was verified that the addition of holo-transferrin increased, and DFO decreased the parasite multiplication in both trophoblastic cells, however, in a more expressive manner in HTR-8/SVneo, indicating that the parasite depends on iron storage in trophoblastic cells for its growth. Also, tachyzoites pretread with DFO proliferate normally in trophoblastic cells demonstrating that DFO itself does not interfere with parasite proliferation. Additionally, T. gondii infection induced enhancement in transferrin receptor mRNA expression levels in trophoblastic cells, and the expression was higher in HTR-8/SVneo compared with BeWo. Finally, DFO-treatment was able to reduce the parasite replication in villous explants. Thus, the iron supplementation can be a double-edged sword; in one hand, it could improve the supplement of an essential ion to embryo/fetus development, and on the other hand, could improve the parasite proliferation enhancing the risk of congenital infection.
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Affiliation(s)
- Marcos Paulo Oliveira Almeida
- Laboratory of Immunopathology, Institute of Biomedical Sciences, Federal University of Uberlândia, Av. Pará 1720, Uberlândia, MG, CEP 38400-902, Brazil
| | - Eloisa Amália Vieira Ferro
- Laboratory of Immunophysiology of Reproduction, Institute of Biomedical Sciences, Federal University of Uberlândia, Av. Pará 1720, Uberlândia, MG, CEP 38400-902, Brazil
| | - Marisol Patricia Pallete Briceño
- Laboratory of Immunopathology, Institute of Biomedical Sciences, Federal University of Uberlândia, Av. Pará 1720, Uberlândia, MG, CEP 38400-902, Brazil
| | - Mário Cézar Oliveira
- Laboratory of Immunopathology, Institute of Biomedical Sciences, Federal University of Uberlândia, Av. Pará 1720, Uberlândia, MG, CEP 38400-902, Brazil
| | - Bellisa Freitas Barbosa
- Laboratory of Immunophysiology of Reproduction, Institute of Biomedical Sciences, Federal University of Uberlândia, Av. Pará 1720, Uberlândia, MG, CEP 38400-902, Brazil
| | - Neide Maria Silva
- Laboratory of Immunopathology, Institute of Biomedical Sciences, Federal University of Uberlândia, Av. Pará 1720, Uberlândia, MG, CEP 38400-902, Brazil.
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10
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Abstract
During pregnancy, iron needs to increase substantially to support fetoplacental development and maternal adaptation to pregnancy. To meet these iron requirements, both dietary iron absorption and the mobilization of iron from stores increase, a mechanism that is in large part dependent on the iron-regulatory hormone hepcidin. In healthy human pregnancies, maternal hepcidin concentrations are suppressed in the second and third trimesters, thereby facilitating an increased supply of iron into the circulation. The mechanism of maternal hepcidin suppression in pregnancy is unknown, but hepcidin regulation by the known stimuli (i.e., iron, erythropoietic activity, and inflammation) appears to be preserved during pregnancy. Inappropriately increased maternal hepcidin during pregnancy can compromise the iron availability for placental transfer and impair the efficacy of iron supplementation. The role of fetal hepcidin in the regulation of placental iron transfer still remains to be characterized. This review summarizes the current understanding and addresses the gaps in knowledge about gestational changes in hematologic and iron variables and regulatory aspects of maternal, fetal, and placental iron homeostasis.
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Affiliation(s)
- Allison L Fisher
- Molecular, Cellular and Integrative Physiology Graduate Program and,Center for Iron Disorders, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA
| | - Elizabeta Nemeth
- Center for Iron Disorders, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA
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11
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Abstract
Iron is an essential element for human development. It is a major requirement for cellular processes such as oxygen transport, energy metabolism, neurotransmitter synthesis, and myelin synthesis. Despite its crucial role in these processes, iron in the ferric form can also produce toxic reactive oxygen species. The duality of iron’s function highlights the importance of maintaining a strict balance of iron levels in the body. As a result, organisms have developed elegant mechanisms of iron uptake, transport, and storage. This review will focus on the mechanisms that have evolved at physiological barriers, such as the intestine, the placenta, and the blood–brain barrier (BBB), where iron must be transported. Much has been written about the processes for iron transport across the intestine and the placenta, but less is known about iron transport mechanisms at the BBB. In this review, we compare the established pathways at the intestine and the placenta as well as describe what is currently known about iron transport at the BBB and how brain iron uptake correlates with processes at these other physiological barriers.
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Affiliation(s)
- Kari A Duck
- Department of Neurosurgery, The Pennsylvania State University College of Medicine, Hershey, PA, USA
| | - James R Connor
- Department of Neurosurgery, The Pennsylvania State University College of Medicine, Hershey, PA, USA.
- Department of Neurosurgery, Neural and Behavioral Sciences and Pediatrics, Center for Aging and Neurodegenerative Diseases, Penn State Hershey Medical Center, 500 University Drive, MC H110, C3830, Hershey, PA, 17033, USA.
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12
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Abstract
Optimal iron nutrition in utero is essential for development of the fetus and helps establish birth iron stores adequate to sustain growth in early infancy. In species with hemochorial placentas, such as humans and rodents, iron in the maternal circulation is transferred to the fetus by directly contacting placental syncytiotrophoblasts. Early kinetic studies provided valuable data on the initial uptake of maternal transferrin, an iron-binding protein, by the placenta. However, the remaining steps of iron trafficking across syncytiotrophoblasts and through the fetal endothelium into the fetal blood remain poorly characterized. Over the last 20 years, identification of transmembrane iron transporters and the iron regulatory hormone hepcidin has greatly expanded the knowledge of cellular iron transport and its regulation by systemic iron status. In addition, emerging human and animal data demonstrating comprised fetal iron stores in severe maternal iron deficiency challenge the classic dogma of exclusive fetal control over the transfer process and indicate that maternal and local signals may play a role in regulating this process. This review compiles current data on the kinetic, molecular, and regulatory aspects of placental iron transport and considers new questions and knowledge gaps raised by these advances.
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Affiliation(s)
- Chang Cao
- C. Cao and M.D. Fleming are with the Department of Pathology, Boston Children's Hospital, Boston, Massachusetts, USA
| | - Mark D Fleming
- C. Cao and M.D. Fleming are with the Department of Pathology, Boston Children's Hospital, Boston, Massachusetts, USA.
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13
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Zhao GY, DI DH, Wang B, Zhang P, Xu YJ. Iron regulates the expression of ferroportin 1 in the cultured hFOB 1.19 osteoblast cell line. Exp Ther Med 2014; 8:826-830. [PMID: 25120608 PMCID: PMC4113530 DOI: 10.3892/etm.2014.1823] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2014] [Accepted: 06/11/2014] [Indexed: 12/16/2022] Open
Abstract
Iron metabolism is tightly regulated in osteoblasts, and ferroportin 1 (FPN1) is the only identified iron exporter in mammals to date. In the present study, the regulation of FNP1 in human osteoblasts was investigated following various iron treatments. The human osteoblast cell line hFOB 1.19 was treated with ferric ammonium citrate (FAC) or desferrioxamine (DFO) of various concentrations. The intracellular iron ion levels were measured using a confocal laser scanning microscope. In addition, the mRNA and protein expression levels of FPN1 were detected by quantitative polymerase chain reaction, western blot analysis and immunofluorescence. The results demonstrated that increasing iron concentrations via FAC treatment increased the expression of FPN1. By contrast, decreasing the iron concentration by DFO treatment decreased FNP1 expression levels. In addition to demonstrating that the FNP1 expression changed according to the iron concentration, the observations indicated that changes in FPN1 expression may contribute to the maintenance of the intracellular iron balance in osteoblasts.
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Affiliation(s)
- Guo-Yang Zhao
- Department of Orthopedics, The Affiliated Hospital of Jiangsu University, Zhenjiang, Jiangsu 212000, P.R. China
| | - Dong-Hua DI
- Department of Orthopedics, The Affiliated Hospital of Jiangsu University, Zhenjiang, Jiangsu 212000, P.R. China
| | - Bo Wang
- Department of Orthopedics, The Affiliated Hospital of Jiangsu University, Zhenjiang, Jiangsu 212000, P.R. China
| | - Peng Zhang
- Department of Orthopedics, The Second Affiliated Hospital of Soochow University, Suzhou, Jiangsu 215004, P.R. China
| | - You-Jia Xu
- Department of Orthopedics, The Second Affiliated Hospital of Soochow University, Suzhou, Jiangsu 215004, P.R. China
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14
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Penha-Gonçalves C, Gozzelino R, de Moraes LV. Iron overload in Plasmodium berghei-infected placenta as a pathogenesis mechanism of fetal death. Front Pharmacol 2014; 5:155. [PMID: 25071574 PMCID: PMC4077027 DOI: 10.3389/fphar.2014.00155] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Accepted: 06/12/2014] [Indexed: 11/17/2022] Open
Abstract
Plasmodium infection during gestation may lead to severe clinical manifestations including abortion, stillbirth, intrauterine growth retardation, and low birth weight. Mechanisms underlying such poor pregnancy outcomes are still unclear. In the animal model of severe placental malaria (PM), in utero fetal death frequently occurs and mothers often succumb to infection before or immediately after delivery. Plasmodium berghei-infected erythrocytes (IEs) continuously accumulate in the placenta, where they are then phagocytosed by fetal-derived placental cells, namely trophoblasts. Inside the phagosomes, disruption of IEs leads to the release of non-hemoglobin bound heme, which is subsequently catabolized by heme oxygenase-1 into carbon monoxide, biliverdin, and labile iron. Fine-tuned regulatory mechanisms operate to maintain iron homeostasis, preventing the deleterious effect of iron-induced oxidative stress. Our preliminary results demonstrate that iron overload in trophoblasts of P. berghei-infected placenta is associated with fetal death. Placentas which supported normally developing embryos showed no iron accumulation within the trophoblasts. Placentas from dead fetuses showed massive iron accumulation, which was associated with parasitic burden. Here we present preliminary data suggesting that disruption of iron homeostasis in trophoblasts during the course of PM is a consequence of heme accumulation after intense IE engulfment. We propose that iron overload in placenta is a pathogenic component of PM, contributing to fetal death. The mechanism through which it operates still needs to be elucidated.
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Multi-copper oxidases and human iron metabolism. Nutrients 2013; 5:2289-313. [PMID: 23807651 PMCID: PMC3738974 DOI: 10.3390/nu5072289] [Citation(s) in RCA: 132] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Revised: 05/29/2013] [Accepted: 06/06/2013] [Indexed: 01/13/2023] Open
Abstract
Multi-copper oxidases (MCOs) are a small group of enzymes that oxidize their substrate with the concomitant reduction of dioxygen to two water molecules. Generally, multi-copper oxidases are promiscuous with regards to their reducing substrates and are capable of performing various functions in different species. To date, three multi-copper oxidases have been detected in humans—ceruloplasmin, hephaestin and zyklopen. Each of these enzymes has a high specificity towards iron with the resulting ferroxidase activity being associated with ferroportin, the only known iron exporter protein in humans. Ferroportin exports iron as Fe2+, but transferrin, the major iron transporter protein of blood, can bind only Fe3+ effectively. Iron oxidation in enterocytes is mediated mainly by hephaestin thus allowing dietary iron to enter the bloodstream. Zyklopen is involved in iron efflux from placental trophoblasts during iron transfer from mother to fetus. Release of iron from the liver relies on ferroportin and the ferroxidase activity of ceruloplasmin which is found in blood in a soluble form. Ceruloplasmin, hephaestin and zyklopen show distinctive expression patterns and have unique mechanisms for regulating their expression. These features of human multi-copper ferroxidases can serve as a basis for the precise control of iron efflux in different tissues. In this manuscript, we review the biochemical and biological properties of the three human MCOs and discuss their potential roles in human iron homeostasis.
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