201
|
Abstract
Anemia in the setting of chronic inflammatory disorders is a very frequent clinical condition, which is, however, often neglected or not properly treated given the problems often caused by the diseases underlying the development of anemia. Mechanistically, anemia is mainly caused by inflammation-driven retention of iron in macrophages making the metal unavailable for heme synthesis in the course of erythropoiesis, and further by impaired biological activity of the red blood cell hormone erythropoietin and the reduced proliferative capacity of erythroid progenitor cells. Anemia can be aggravated by chronic blood loss, as found in subjects with gastrointestinal cancers, inflammatory or infectious bowel disease, or iatrogenic blood loss in the setting of dialysis, all resulting in true iron deficiency. The identification of such patients is a clinical necessity because these individuals need contrasting therapies in comparison to subjects suffering from only classical anemia of chronic disorders. The diagnosis is challenging because no state of the art laboratory test is currently available that can clearly separate patients with inflammatory anemia from those with additional true iron deficiency. However, based on our expanding knowledge on the pathophysiology of inflammatory anemia, new diagnostic markers, including the iron-regulatory hormone hepcidin, and hematologic parameters emerge. Apart from traditional anemia treatments such as blood transfusions, recombinant erythropoietin, and iron, including new high-molecular-weight formulations, new therapeutics are currently under preclinical and clinical evaluation. These novel compounds aim at correcting anemia by multiple pathways, including antagonizing the inflammation- and hepcidin-driven retention of iron in the monocyte-macrophage system and thereby promoting the supply of iron for erythropoiesis or by stimulating the endogenous formation of erythopoietin via stabilization of hypoxia-regulated factors.
Collapse
Affiliation(s)
- Guenter Weiss
- Department of Internal Medicine VI, Infectious Diseases, Immunology, Rheumatology, Pneumology, Medical University of Innsbruck, Innsbruck, Austria.
| |
Collapse
|
202
|
Abstract
Iron is an essential trace element for multicellular organisms and nearly all microorganisms. Although iron is abundant in the environment, common forms of iron are minimally soluble and therefore poorly accessible to biological organisms. Microorganisms entering a mammalian host face multiple mechanisms that further restrict their ability to obtain iron and thereby limit their pathogenicity. Iron levels also modulate host defence, as iron content in macrophages regulates their cytokine production. Here, we review recent advances that highlight the role of systemic and cellular iron-regulating mechanisms in protecting hosts from infection, emphasizing aspects that are applicable to human health and disease.
Collapse
Affiliation(s)
- Tomas Ganz
- 1] Department of Medicine, David Geffen School of Medicine at University of California. [2] Department of Pathology, David Geffen School of Medicine at University of California, Los Angeles, California 90095-1690, USA
| | - Elizabeta Nemeth
- Department of Medicine, David Geffen School of Medicine at University of California
| |
Collapse
|
203
|
Compartmentalization of iron between mitochondria and the cytosol and its regulation. Eur J Cell Biol 2015; 94:292-308. [DOI: 10.1016/j.ejcb.2015.05.003] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
|
204
|
|
205
|
Abstract
Iron-sulfur clusters act as important cofactors for a number of transcriptional regulators in bacteria, including many mammalian pathogens. The sensitivity of iron-sulfur clusters to iron availability, oxygen tension, and reactive oxygen and nitrogen species enables bacteria to use such regulators to adapt their gene expression profiles rapidly in response to changing environmental conditions. In this review, we discuss how the [4Fe-4S] or [2Fe-2S] cluster-containing regulators FNR, Wbl, aconitase, IscR, NsrR, SoxR, and AirSR contribute to bacterial pathogenesis through control of both metabolism and classical virulence factors. In addition, we briefly review mammalian iron homeostasis as well as oxidative/nitrosative stress to provide context for understanding the function of bacterial iron-sulfur cluster sensors in different niches within the host.
Collapse
Affiliation(s)
- Halie K Miller
- Department of Microbiology and Environmental Toxicology, University of California Santa Cruz, 1156 High Street, Santa Cruz, CA 95064, USA.
| | | |
Collapse
|
206
|
Renberg RL, Yuan X, Samuel TK, Miguel DC, Hamza I, Andrews NW, Flannery AR. The Heme Transport Capacity of LHR1 Determines the Extent of Virulence in Leishmania amazonensis. PLoS Negl Trop Dis 2015; 9:e0003804. [PMID: 26001191 PMCID: PMC4441390 DOI: 10.1371/journal.pntd.0003804] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Accepted: 05/01/2015] [Indexed: 12/14/2022] Open
Abstract
Leishmania spp. are trypanosomatid parasites that replicate intracellularly in macrophages, causing serious human morbidity and mortality throughout the world. Trypanosomatid protozoa cannot synthesize heme, so must acquire this essential cofactor from their environment. Earlier studies identified LHR1 as a Leishmania amazonensis transmembrane protein that mediates heme uptake. Null mutants of LHR1 are not viable and single knockout strains have reduced virulence, but very little is known about the properties of LHR1 directly associated with heme transport. Here, we use functional assays in Saccharomyces cerevisiae to show that specific tyrosine residues within the first three predicted transmembrane domains of LHR1 are required for efficient heme uptake. These tyrosines are unique to LHR1, consistent with the low similarity between LHR1 and its corresponding homologs in C. elegans and human. Substitution of these tyrosines in LHR1 resulted in varying degrees of heme transport inhibition, phenotypes that closely mirrored the impaired ability of L. amazonensis to replicate as intracellular amastigotes in macrophages and generate cutaneous lesions in mice. Taken together, our results imply that the mechanism for heme transport by LHR1 is distinctive and may have adapted to secure heme, a limiting cofactor, inside the host. Since LHR1 is significantly divergent from the human heme transporter HRG1, our findings lay the groundwork for selective targeting of LHR1 by small molecule antagonists. Leishmania are protozoan parasites that infect humans and replicate intracellularly in macrophages, cells normally engaged in protecting the host from pathogens. These parasites have several strategies to survive inside the hostile environment of the host macrophage, and one of these strategies involves heme acquisition. Heme is an iron-containing molecule that is essential for many cellular functions. Unlike mammalian cells, Leishmania parasites cannot synthesize heme, so must acquire it from the host cell. In earlier work we found that the parasites express a surface protein, LHR1, which transports heme into the parasites. In this study we identified specific amino acids in LHR1 that are required for heme transport. When expressed in yeast cells, LHR1 carrying these mutations had defects in heme transport that were equivalent to the inhibition in virulence observed when these proteins were expressed in Leishmania and tested in macrophage and mouse infection assays. These critical amino acids do not exist in the human heme transporter, indicating that LHR1 is a promising target for the development of specific drugs for the treatment of leishmaniasis and possibly other serious parasitic diseases, such as Chagas’ disease and sleeping sickness.
Collapse
Affiliation(s)
- Rebecca L. Renberg
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland, United States of America
| | - Xiaojing Yuan
- Department of Animal and Avian Sciences, University of Maryland, College Park, Maryland, United States of America
| | - Tamika K. Samuel
- Department of Animal and Avian Sciences, University of Maryland, College Park, Maryland, United States of America
| | - Danilo C. Miguel
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland, United States of America
| | - Iqbal Hamza
- Department of Animal and Avian Sciences, University of Maryland, College Park, Maryland, United States of America
| | - Norma W. Andrews
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland, United States of America
- * E-mail: ,
| | - Andrew R. Flannery
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland, United States of America
- PathSensors, Inc., Baltimore, Maryland, United States of America
| |
Collapse
|
207
|
Transferrin: Endocytosis and Cell Signaling in Parasitic Protozoa. BIOMED RESEARCH INTERNATIONAL 2015; 2015:641392. [PMID: 26090431 PMCID: PMC4450279 DOI: 10.1155/2015/641392] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Accepted: 12/18/2014] [Indexed: 12/31/2022]
Abstract
Iron is the fourth most abundant element on Earth and the most abundant metal in the human body. This element is crucial for life because almost all organisms need iron for several biological activities. This is the case with pathogenic organisms, which are at the vanguard in the battle with the human host for iron. The latest regulates Fe concentration through several iron-containing proteins, such as transferrin. The transferrin receptor transports iron to each cell that needs it and maintains it away from pathogens. Parasites have developed several strategies to obtain iron as the expression of specific transferrin receptors localized on plasma membrane, internalized through endocytosis. Signal transduction pathways related to the activation of the receptor have functional importance in proliferation. The study of transferrin receptors and other proteins with action in the signaling networks is important because these proteins could be used as therapeutic targets due to their specificity or to differences with the human counterpart. In this work, we describe proteins that participate in signal transduction processes, especially those that involve transferrin endocytosis, and we compare these processes with those found in T. brucei, T. cruzi, Leishmania spp., and E. histolytica parasites.
Collapse
|
208
|
Iron Homeostasis and Trypanosoma brucei Associated Immunopathogenicity Development: A Battle/Quest for Iron. BIOMED RESEARCH INTERNATIONAL 2015; 2015:819389. [PMID: 26090446 PMCID: PMC4450282 DOI: 10.1155/2015/819389] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Revised: 02/11/2015] [Accepted: 02/15/2015] [Indexed: 12/24/2022]
Abstract
African trypanosomosis is a chronic debilitating disease affecting the health and economic well-being of developing countries. The immune response during African trypanosome infection consisting of a strong proinflammatory M1-type activation of the myeloid phagocyte system (MYPS) results in iron deprivation for these extracellular parasites. Yet, the persistence of M1-type MYPS activation causes the development of anemia (anemia of chronic disease, ACD) as a most prominent pathological parameter in the mammalian host, due to enhanced erythrophagocytosis and retention of iron within the MYPS thereby depriving iron for erythropoiesis. In this review we give an overview of how parasites acquire iron from the host and how iron modulation of the host MYPS affects trypanosomosis-associated anemia development. Finally, we also discuss different strategies at the level of both the host and the parasite that can/might be used to modulate iron availability during African trypanosome infections.
Collapse
|
209
|
Strategies of Intracellular Pathogens for Obtaining Iron from the Environment. BIOMED RESEARCH INTERNATIONAL 2015; 2015:476534. [PMID: 26120582 PMCID: PMC4450229 DOI: 10.1155/2015/476534] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Accepted: 02/09/2015] [Indexed: 12/22/2022]
Abstract
Most microorganisms are destroyed by the host tissues through processes that usually involve phagocytosis and lysosomal disruption. However, some organisms, called intracellular pathogens, are capable of avoiding destruction by growing inside macrophages or other cells. During infection with intracellular pathogenic microorganisms, the element iron is required by both the host cell and the pathogen that inhabits the host cell. This minireview focuses on how intracellular pathogens use multiple strategies to obtain nutritional iron from the intracellular environment in order to use this element for replication. Additionally, the implications of these mechanisms for iron acquisition in the pathogen-host relationship are discussed.
Collapse
|
210
|
Weiss G. Dietary iron supplementation: a proinflammatory attack on the intestine? Gut 2015; 64:696-7. [PMID: 25331454 DOI: 10.1136/gutjnl-2014-308147] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Accepted: 10/03/2014] [Indexed: 12/08/2022]
|
211
|
Sheldon JR, Heinrichs DE. Recent developments in understanding the iron acquisition strategies of gram positive pathogens. FEMS Microbiol Rev 2015; 39:592-630. [DOI: 10.1093/femsre/fuv009] [Citation(s) in RCA: 166] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/04/2015] [Indexed: 12/26/2022] Open
|
212
|
The utility of iron chelators in the management of inflammatory disorders. Mediators Inflamm 2015; 2015:516740. [PMID: 25878400 PMCID: PMC4386698 DOI: 10.1155/2015/516740] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Revised: 09/01/2014] [Accepted: 09/01/2014] [Indexed: 01/19/2023] Open
Abstract
Since iron can contribute to detrimental radical generating processes through the Fenton and Haber-Weiss reactions, it seems to be a reasonable approach to modulate iron-related pathways in inflammation. In the human organism a counterregulatory reduction in iron availability is observed during inflammatory diseases. Under pathological conditions with reduced or increased baseline iron levels different consequences regarding protection or susceptibility to inflammation have to be considered. Given the role of iron in development of inflammatory diseases, pharmaceutical agents targeting this pathway promise to improve the clinical outcome. The objective of this review is to highlight the mechanisms of iron regulation and iron chelation, and to demonstrate the potential impact of this strategy in the management of several acute and chronic inflammatory diseases, including cancer.
Collapse
|
213
|
Abstract
Macrophages and neutrophils play a decisive role in host responses to intracellular bacteria including the agent of tuberculosis (TB), Mycobacterium tuberculosis as they represent the forefront of innate immune defense against bacterial invaders. At the same time, these phagocytes are also primary targets of intracellular bacteria to be abused as host cells. Their efficacy to contain and eliminate intracellular M. tuberculosis decides whether a patient initially becomes infected or not. However, when the infection becomes chronic or even latent (as in the case of TB) despite development of specific immune activation, phagocytes have also important effector functions. Macrophages have evolved a myriad of defense strategies to combat infection with intracellular bacteria such as M. tuberculosis. These include induction of toxic anti-microbial effectors such as nitric oxide and reactive oxygen intermediates, the stimulation of microbe intoxication mechanisms via acidification or metal accumulation in the phagolysosome, the restriction of the microbe's access to essential nutrients such as iron, fatty acids, or amino acids, the production of anti-microbial peptides and cytokines, along with induction of autophagy and efferocytosis to eliminate the pathogen. On the other hand, M. tuberculosis, as a prime example of a well-adapted facultative intracellular bacterium, has learned during evolution to counter-balance the host's immune defense strategies to secure survival or multiplication within this otherwise hostile environment. This review provides an overview of innate immune defense of macrophages directed against intracellular bacteria with a focus on M. tuberculosis. Gaining more insights and knowledge into this complex network of host-pathogen interaction will identify novel target sites of intervention to successfully clear infection at a time of rapidly emerging multi-resistance of M. tuberculosis against conventional antibiotics.
Collapse
Affiliation(s)
- Günter Weiss
- Department of Internal Medicine VI, Infectious Disease, Immunology, Rheumatology, Pneumology, Medical University of InnsbruckInnsbruck, Austria
| | - Ulrich E Schaible
- Cellular Microbiology, Priority Area Infections, Research Center BorstelBorstel, Germany
- Department of Immunology, London School of Hygiene and Tropical MedicineLondon, UK
- German Centre of Infection Research, TTU-TBBorstel, Germany
| |
Collapse
|
214
|
Chang HC, Bayeva M, Taiwo B, Palella FJ, Hope TJ, Ardehali H. Short communication: high cellular iron levels are associated with increased HIV infection and replication. AIDS Res Hum Retroviruses 2015; 31:305-12. [PMID: 25291189 DOI: 10.1089/aid.2014.0169] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
HIV is a pandemic disease, and many cellular and systemic factors are known to alter its infectivity and replication. Earlier studies had suggested that anemia is common in HIV-infected patients; however, higher iron was also observed in AIDS patients prior to the introduction of antiretroviral therapy (ART). Therefore, the relationship between iron and viral infection is not well delineated. To address this issue, we altered the levels of cellular iron in primary CD4(+) T cells and showed that higher iron is associated with increased HIV infection and replication. In addition, HIV infection alone leads to increased cellular iron, and several ART drugs increase cellular iron independent of HIV infection. Finally, HIV infection is associated with increased serum iron in HIV-positive patients regardless of treatment with ART. These results establish a relationship between iron and HIV infection and suggest that iron homeostasis may be a viable therapeutic target for HIV.
Collapse
Affiliation(s)
- Hsiang-Chun Chang
- Feinberg Cardiovascular Research Institute, Northwestern University School of Medicine, Chicago, Illinois
| | - Marina Bayeva
- Feinberg Cardiovascular Research Institute, Northwestern University School of Medicine, Chicago, Illinois
| | - Babafemi Taiwo
- Division of Infectious Disease, Department of Medicine, Northwestern University School of Medicine, Chicago, Illinois
| | - Frank J. Palella
- Division of Infectious Disease, Department of Medicine, Northwestern University School of Medicine, Chicago, Illinois
| | - Thomas J. Hope
- Department of Cell and Molecular Biology, Northwestern University School of Medicine, Chicago, Illinois
| | - Hossein Ardehali
- Feinberg Cardiovascular Research Institute, Northwestern University School of Medicine, Chicago, Illinois
| |
Collapse
|
215
|
Aldridge JR, Vogel IA. Macrophage biology and their activation by protozoan-derived glycosylphosphatidylinositol anchors and hemozoin. J Parasitol 2015; 100:737-42. [PMID: 25265042 DOI: 10.1645/14-646.1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Despite recent advances in medical technology and a global effort to improve public health and hygiene, parasitic infections remain a major health and economic burden worldwide. The World Health Organization estimates that about 1/3 of the world's population is currently infected with a soil-transmitted helminth, and millions more suffer from diseases caused by protozoan parasites including Plasmodium, Trypanosoma, and Leishmania species. Due to the selective pressure applied by parasitic and other infections, animals have evolved an intricate immune system; however, the current worldwide prevalence of parasitic infections clearly indicates that these pathogens have adapted equally well. Thus, developing a better understanding of the host-parasite relationship, particularly by focusing on the host immune response and the mechanisms by which parasites evade this response, is a critical first step in mitigating the detrimental effects of parasitic diseases. Macrophages are critical contributors during the host response to protozoan parasites, and the success or failure of these cells often tips the balance in favor of the host or parasite. Herein, we briefly discuss macrophage biology and provide an update on our current understanding of how these cells recognize glycosylphosphatidylinositol anchors from protozoan parasites as well as malarial hemozoin.
Collapse
Affiliation(s)
- Jerry R Aldridge
- Institute of Parasitology, McGill University, MacDonald Campus, 21,111 Lakeshore Ave., St-Anne-de-Bellevue, Quebec H9X 3V9, Canada
| | | |
Collapse
|
216
|
Gozzelino R, Arosio P. The importance of iron in pathophysiologic conditions. Front Pharmacol 2015; 6:26. [PMID: 25759669 PMCID: PMC4338679 DOI: 10.3389/fphar.2015.00026] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Accepted: 01/30/2015] [Indexed: 11/26/2022] Open
Affiliation(s)
| | - Paolo Arosio
- Department of Molecular and Translational Medicine, University of Brescia Brescia, Italy
| |
Collapse
|
217
|
Bogdan C. Nitric oxide synthase in innate and adaptive immunity: an update. Trends Immunol 2015; 36:161-78. [PMID: 25687683 DOI: 10.1016/j.it.2015.01.003] [Citation(s) in RCA: 561] [Impact Index Per Article: 62.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Revised: 01/14/2015] [Accepted: 01/14/2015] [Indexed: 12/22/2022]
Abstract
Thirty years after the discovery of its production by activated macrophages, our appreciation of the diverse roles of nitric oxide (NO) continues to grow. Recent findings have not only expanded our understanding of the mechanisms controlling the expression of NO synthases (NOS) in innate and adaptive immune cells, but have also revealed new functions and modes of action of NO in the control and escape of infectious pathogens, in T and B cell differentiation, and in tumor defense. I discuss these findings, in the context of a comprehensive overview of the various sources and multiple reaction partners of NO, and of the regulation of NOS2 by micromilieu factors, antisense RNAs, and 'unexpected' cytokines.
Collapse
Affiliation(s)
- Christian Bogdan
- Mikrobiologisches Institut - Klinische Mikrobiologie, Immunologie, und Hygiene, Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg, Universitätsklinikum Erlangen, Wasserturmstraße 3/5, 91054 Erlangen, Germany.
| |
Collapse
|
218
|
Lasocki S, Gaillard T, Rineau E. Iron is essential for living! CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2014; 18:678. [PMID: 25673336 PMCID: PMC4331421 DOI: 10.1186/s13054-014-0678-7] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Iron as an element is a double-edged sword, essential for living but also potentially toxic through the generation of oxidative stress. The recent study by Chen and colleagues in Critical Care reminds us of this elegantly. In a mouse model of acute lung injury, they showed that silencing hepcidin (the master regulator of iron metabolism) locally in airway epithelial cells aggravates lung injury by increasing the release of iron from alveolar macrophages, which in turn enhances pulmonary bacterial growth and reduces the macrophages’ killing properties. This work underscores that hepcidin acts not only systematically (as a hormone) but also locally for iron metabolism regulation. This opens areas of research for sepsis treatment but also for iron deficiency or anaemia treatment, since the local and systemic iron regulation appear to be independent.
Collapse
|
219
|
Aigner E, Feldman A, Datz C. Obesity as an emerging risk factor for iron deficiency. Nutrients 2014; 6:3587-600. [PMID: 25215659 PMCID: PMC4179177 DOI: 10.3390/nu6093587] [Citation(s) in RCA: 189] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Revised: 08/29/2014] [Accepted: 09/03/2014] [Indexed: 12/14/2022] Open
Abstract
Iron homeostasis is affected by obesity and obesity-related insulin resistance in a many-facetted fashion. On one hand, iron deficiency and anemia are frequent findings in subjects with progressed stages of obesity. This phenomenon has been well studied in obese adolescents, women and subjects undergoing bariatric surgery. On the other hand, hyperferritinemia with normal or mildly elevated transferrin saturation is observed in approximately one-third of patients with metabolic syndrome (MetS) or nonalcoholic fatty liver disease (NAFLD). This constellation has been named the “dysmetabolic iron overload syndrome (DIOS)”. Both elevated body iron stores and iron deficiency are detrimental to health and to the course of obesity-related conditions. Iron deficiency and anemia may impair mitochondrial and cellular energy homeostasis and further increase inactivity and fatigue of obese subjects. Obesity-associated inflammation is tightly linked to iron deficiency and involves impaired duodenal iron absorption associated with low expression of duodenal ferroportin (FPN) along with elevated hepcidin concentrations. This review summarizes the current understanding of the dysregulation of iron homeostasis in obesity.
Collapse
Affiliation(s)
- Elmar Aigner
- First Department of Medicine, Paracelsus Medical University, Müllner Hauptstrasse 48, 5020 Salzburg, Austria.
| | - Alexandra Feldman
- First Department of Medicine, Paracelsus Medical University, Müllner Hauptstrasse 48, 5020 Salzburg, Austria.
| | - Christian Datz
- Obesity Research Unit, Paracelsus Medical University, Müllner Hauptstrasse 48, 5020 Salzburg, Austria.
| |
Collapse
|