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Hurtado-Aréstegui A, Rosales-Mendoza K, Venegas-Justiniano Y, Gonzales-Polar J, Barreto-Jara R, Palacios-Guillén AM. Hemoglobin Levels in Peruvian Patients with Chronic Kidney Disease at Different Altitudes. High Alt Med Biol 2023; 24:209-213. [PMID: 37311154 DOI: 10.1089/ham.2023.0046] [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] [Indexed: 06/15/2023] Open
Abstract
Hurtado-Aréstegui, Abdías, Karina Rosales-Mendoza, Yanissa Venegas-Justiniano, José Gonzales-Polar, Rina Barreto-Jara, and Alaciel Melissa Palacios-Guillén. Hemoglobin levels in Peruvian patients with chronic kidney disease at different altitudes. High Alt Med Biol. 24:209-213, 2023. Background: Decreased hemoglobin is a manifestation of chronic kidney disease (CKD), and people who reside at high altitude adapt to hypoxia by increasing their hemoglobin. The study's objective was to determine the influence of altitude and the associated factors on the hemoglobin levels of patients with CKD who were not on dialysis (ND). Methods: This exploratory and cross-sectional study was carried out in three Peruvian cities, located at different altitudes: (1) "sea level" (161 m), (2) "moderate altitude" (2,335 m), and "high altitude" (3,399 m). The study included female and male individuals between 20 and 90 years old, with CKD stage 3a, through stage 5. Results: Of the 256 volunteers evaluated, 92 lived at sea level, 82 at moderate altitude, and 82 at high altitude. The three groups were similar in age, number of volunteers in each CKD stage, systolic blood pressure, and diastolic blood pressure. Hemoglobin levels were statistically different according to gender (p = 0.024), CKD stage, and altitude (p < 0.001). High-altitude dwellers had higher hemoglobin by 2.5 g/dl (95% confidence interval: 1.8-3.1, p < 0.001) than those living at lower altitudes (adjusted for gender, age, nutritional status, and smoking habit). For all CKD stages, the high-altitude population had higher hemoglobin levels than population at moderate altitude and at sea level. Conclusion: Subjects living at high altitude with CKD stages 3 to 5 who are yet ND have higher hemoglobin levels than those who live at moderate altitude and at sea level.
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Affiliation(s)
- Abdías Hurtado-Aréstegui
- Nephrology Division, Hospital Nacional Arzobispo Loayza, Lima, Perú
- Department of Medicine, Universidad Peruana Cayetano Heredia, Lima, Perú
| | - Karina Rosales-Mendoza
- Nephrology Division, Hospital Nacional Arzobispo Loayza, Lima, Perú
- Department of Medicine, Universidad Peruana Cayetano Heredia, Lima, Perú
| | - Yanissa Venegas-Justiniano
- Nephrology Division, Hospital Nacional Arzobispo Loayza, Lima, Perú
- Department of Medicine, Universidad Peruana Cayetano Heredia, Lima, Perú
| | | | - Rina Barreto-Jara
- Nephrology Division, Hospital Nacional Adolfo Guevara Velasco, Cuzco, Perú
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2
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Yoshida S, Saito T, Shibagaki K, Hirao K, Yuza T, Tomosugi N, Honda H. Changes of biomarkers for erythropoiesis, iron metabolism, and FGF23 by supplementation with roxadustat in patients on hemodialysis. Sci Rep 2023; 13:3181. [PMID: 36823243 PMCID: PMC9950357 DOI: 10.1038/s41598-023-30331-6] [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] [Received: 12/26/2022] [Accepted: 02/21/2023] [Indexed: 02/25/2023] Open
Abstract
This study aimed to confirm changes in biomarkers of erythropoiesis and iron metabolism and serum fibroblast growth factor 23 (FGF-23) during darbepoetin-α treatment and then switching to the hypoxia-inducible factor prolyl hydroxylase inhibitor roxadustat. A total of 28 patients on hemodialysis who received weekly doses of darbepoetin-α were switched to roxadustat. Biomarkers for erythropoiesis and iron metabolism and intact and C-terminal FGF-23 were measured in blood samples collected before the HD session on days - 7 (darbepoetin-α injection), - 4, and - 2, and days 0 (switch to roxadustat treatment, three times weekly), 3, 5, 7, 14, 21, and 28. Erythropoietin and erythroferrone levels were elevated on day - 4 by darbepoetin-α injection and decreased to baseline levels at day 0. Levels of erythropoietin were not significantly increased by roxadustat supplementation, but erythroferrone levels were continuously elevated, similar to darbepoetin-α treatment. Hepcidin-25 and total iron binding capacity were significantly decreased or increased in patients treated with roxadustat compared with darbepoetin-α. Changes of intact and C-terminal FGF-23 levels were parallel to changes of phosphate levels during roxadustat treatment. However, the actual and percentage changes of intact FGF-23 and C-terminal FGF-23 in patients with low ferritin levels were greater than those in patients with high ferritin levels. Roxadustat might stimulate erythropoiesis by increasing iron usage through hepcidin-25, which was suppressed by erythroferrone in the physiological erythropoietin condition. Changes of intact FGF-23 and C-terminal FGF-23 levels might be affected by roxadustat in patients on hemodialysis, especially those with a low-iron condition.
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Affiliation(s)
- Shunsuke Yoshida
- grid.410714.70000 0000 8864 3422Division of Nephrology, Department of Medicine, Showa University School of Medicine, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo, 142-8666 Japan
| | - Tomohiro Saito
- grid.410714.70000 0000 8864 3422Division of Nephrology, Department of Medicine, Showa University School of Medicine, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo, 142-8666 Japan
| | | | | | | | - Naohisa Tomosugi
- grid.411998.c0000 0001 0265 5359Division of Systems Bioscience for Drug Discovery, Medical Research Institute, Kanazawa Medical University, Kanazawa, Japan
| | - Hirokazu Honda
- Division of Nephrology, Department of Medicine, Showa University School of Medicine, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo, 142-8666, Japan.
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3
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Rytz CL, Pun M, Mawhinney JA, Mounsey CA, Mura M, Martin A, Pialoux V, Hartmann SE, Furian M, Rawling JM, Lopez I, Soza D, Moraga FA, Lichtblau M, Bader PR, Ulrich S, Bloch KE, Frise MC, Poulin MJ. Differential Effects of High-Altitude Exposure on Markers of Oxidative Stress, Antioxidant Capacity and Iron Profiles. Am J Physiol Regul Integr Comp Physiol 2022; 323:R445-R456. [PMID: 35938686 DOI: 10.1152/ajpregu.00321.2021] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
High altitude (HA) exposure may stimulate significant physiological and molecular changes, resulting in HA-related illnesses. HA may impact oxidative stress, antioxidant capacity and iron homeostasis, yet it is unclear how both repeated exposure and HA acclimatization may modulate such effects. Therefore, we assessed the effects of weeklong repeated daily HA exposure (2,900m to 5,050m) in altitude-naïve individuals (n=21, 13 females, mean ± SD, 25.3 ± 3.7 years) to mirror the working schedule of HA workers (n=19, all males, 40.1 ± 2.1 years) at the Atacama Large Millimeter Array (ALMA) Observatory (San Pedro de Atacama, Chile). Markers of oxidative stress, antioxidant capacity and iron homeostasis were measured in blood plasma. Levels of protein oxidation (p<0.001) and catalase activity (p=0.023) increased and serum iron (p<0.001), serum ferritin (p<0.001) and transferrin saturation (p<0.001) levels decreased with HA exposure in both groups. HA workers had lower levels of oxidative stress, and higher levels of antioxidant capacity, iron supply and hemoglobin concentration as compared to altitude-naïve individuals. Upon a second week of daily HA exposure, changes in levels of protein oxidation, glutathione peroxidase and nitric oxide metabolites were lower as compared to the first week in altitude-naïve individuals. These results indicate that repeated exposure to HA may significantly alter oxidative stress and iron homeostasis, and the degree of such changes may be dependent on if HA is visited naïvely or routinely. Further studies are required to fully elucidate differences in HA-induced changes in oxidative stress and iron homeostasis profiles amongst visitors of HA.
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Affiliation(s)
- Chantal L Rytz
- Libin Cardiovascular Institute, Calgary, Canada.,Cumming School of Medicine, University of Calgary, Calgary, Canada
| | - Matiram Pun
- Cumming School of Medicine, University of Calgary, Calgary, Canada.,Hotchkiss Brain Institute, University of Calgary, Calgary, Canada
| | - Jamie A Mawhinney
- Department of Plastic Surgery, Queen Alexandra Hospital, Portsmouth University Hospital NHS Foundation Trust, UK
| | | | - Mathilde Mura
- Univ Lyon, University Lyon 1, Team "Atherosclerosis, Thrombosis and Physical Activity", Lyon, France
| | - Agnès Martin
- Univ Lyon, University Lyon 1, Team "Atherosclerosis, Thrombosis and Physical Activity", Lyon, France
| | - Vincent Pialoux
- Univ Lyon, University Lyon 1, Team "Atherosclerosis, Thrombosis and Physical Activity", Lyon, France
| | - Sara E Hartmann
- Cumming School of Medicine, University of Calgary, Calgary, Canada.,Department of Physiology and Pharmacology, University of Calgary, Calgary, Canada.,Hotchkiss Brain Institute, University of Calgary, Calgary, Canada
| | - Michael Furian
- Pulmonary Division, Sleep Disorders Centre and Pulmonary Hypertension Clinic, University Hospital Zurich, Zurich, Switzerland
| | - Jean M Rawling
- Department of Family Medicine at the University of Calgary, Calgary, Canada
| | - Ivan Lopez
- Safety Group, Atacama Large Millimeter Submillimeter Array, Calama, Chile
| | - Daniel Soza
- Safety Group, Atacama Large Millimeter Submillimeter Array, Calama, Chile
| | - Fernando A Moraga
- Laboratorio de Fisiología, Hipoxia y Función Vascular, Departamento de Ciencias Biomédicas, Facultad de Medicina, Universidad Católica del Norte, Coquimbo, Chile
| | - Mona Lichtblau
- Pulmonary Division, Sleep Disorders Centre and Pulmonary Hypertension Clinic, University Hospital Zurich, Zurich, Switzerland
| | - Patrick R Bader
- Pulmonary Division, Sleep Disorders Centre and Pulmonary Hypertension Clinic, University Hospital Zurich, Zurich, Switzerland
| | - Silvia Ulrich
- Pulmonary Division, Sleep Disorders Centre and Pulmonary Hypertension Clinic, University Hospital Zurich, Zurich, Switzerland
| | - Konrad E Bloch
- Pulmonary Division, Sleep Disorders Centre and Pulmonary Hypertension Clinic, University Hospital Zurich, Zurich, Switzerland
| | - Matthew C Frise
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK; Intensive Care Unit, Royal Berkshire Hospitals NHS Foundation Trust, Reading, UK
| | - Marc J Poulin
- Libin Cardiovascular Institute, Calgary, Canada.,Cumming School of Medicine, University of Calgary, Calgary, Canada.,Department of Physiology and Pharmacology, University of Calgary, Calgary, Canada.,Hotchkiss Brain Institute, University of Calgary, Calgary, Canada.,Faculty of Kinesiology, University of Calgary, Calgary, Canada
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4
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Novel insights into alcoholic liver disease: Iron overload, iron sensing and hemolysis. J Transl Int Med 2022; 10:92-124. [PMID: 35959455 PMCID: PMC9328032 DOI: 10.2478/jtim-2021-0056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The liver is the major target organ of continued alcohol consumption at risk and resulting alcoholic liver disease (ALD) is the most common liver disease worldwide. The underlying molecular mechanisms are still poorly understood despite decades of scientific effort limiting our abilities to identify those individuals who are at risk to develop the disease, to develop appropriate screening strategies and, in addition, to develop targeted therapeutic approaches. ALD is predestined for the newly evolving translational medicine, as conventional clinical and health care structures seem to be constrained to fully appreciate this disease. This concept paper aims at summarizing the 15 years translational experience at the Center of Alcohol Research in Heidelberg, namely based on the long-term prospective and detailed characterization of heavy drinkers with mortality data. In addition, novel experimental findings will be presented. A special focus will be the long-known hepatic iron accumulation, the somewhat overlooked role of the hematopoietic system and novel insights into iron sensing and the role of hepcidin. Our preliminary work indicates that enhanced red blood cell (RBC) turnover is critical for survival in ALD patients. RBC turnover is not primarily due to vitamin deficiency but rather to ethanol toxicity directly targeted to erythrocytes but also to the bone marrow stem cell compartment. These novel insights also help to explain long-known aspects of ALD such as mean corpuscular volume of erythrocytes (MCV) and elevated aspartate transaminase (GOT/AST) levels. This work also aims at identifying future projects, naming unresolved observations, and presenting novel hypothetical concepts still requiring future validation.
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5
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Correnti M, Gammella E, Cairo G, Recalcati S. Iron Mining for Erythropoiesis. Int J Mol Sci 2022; 23:ijms23105341. [PMID: 35628152 PMCID: PMC9140467 DOI: 10.3390/ijms23105341] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Revised: 05/05/2022] [Accepted: 05/09/2022] [Indexed: 01/27/2023] Open
Abstract
Iron is necessary for essential processes in every cell of the body, but the erythropoietic compartment is a privileged iron consumer. In fact, as a necessary component of hemoglobin and myoglobin, iron assures oxygen distribution; therefore, a considerable amount of iron is required daily for hemoglobin synthesis and erythroid cell proliferation. Therefore, a tight link exists between iron metabolism and erythropoiesis. The liver-derived hormone hepcidin, which controls iron homeostasis via its interaction with the iron exporter ferroportin, coordinates erythropoietic activity and iron homeostasis. When erythropoiesis is enhanced, iron availability to the erythron is mainly ensured by inhibiting hepcidin expression, thereby increasing ferroportin-mediated iron export from both duodenal absorptive cells and reticuloendothelial cells that process old and/or damaged red blood cells. Erythroferrone, a factor produced and secreted by erythroid precursors in response to erythropoietin, has been identified and characterized as a suppressor of hepcidin synthesis to allow iron mobilization and facilitate erythropoiesis.
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6
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Frise MC, Holdsworth DA, Johnson AW, Chung YJ, Curtis MK, Cox PJ, Clarke K, Tyler DJ, Roberts DJ, Ratcliffe PJ, Dorrington KL, Robbins PA. Abnormal whole-body energy metabolism in iron-deficient humans despite preserved skeletal muscle oxidative phosphorylation. Sci Rep 2022; 12:998. [PMID: 35046429 PMCID: PMC8770476 DOI: 10.1038/s41598-021-03968-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Accepted: 12/10/2021] [Indexed: 01/01/2023] Open
Abstract
Iron deficiency impairs skeletal muscle metabolism. The underlying mechanisms are incompletely characterised, but animal and human experiments suggest the involvement of signalling pathways co-dependent upon oxygen and iron availability, including the pathway associated with hypoxia-inducible factor (HIF). We performed a prospective, case-control, clinical physiology study to explore the effects of iron deficiency on human metabolism, using exercise as a stressor. Thirteen iron-deficient (ID) individuals and thirteen iron-replete (IR) control participants each underwent 31P-magnetic resonance spectroscopy of exercising calf muscle to investigate differences in oxidative phosphorylation, followed by whole-body cardiopulmonary exercise testing. Thereafter, individuals were given an intravenous (IV) infusion, randomised to either iron or saline, and the assessments repeated ~ 1 week later. Neither baseline iron status nor IV iron significantly influenced high-energy phosphate metabolism. During submaximal cardiopulmonary exercise, the rate of decline in blood lactate concentration was diminished in the ID group (P = 0.005). Intravenous iron corrected this abnormality. Furthermore, IV iron increased lactate threshold during maximal cardiopulmonary exercise by ~ 10%, regardless of baseline iron status. These findings demonstrate abnormal whole-body energy metabolism in iron-deficient but otherwise healthy humans. Iron deficiency promotes a more glycolytic phenotype without having a detectable effect on mitochondrial bioenergetics.
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Affiliation(s)
- Matthew C Frise
- Department of Physiology, Anatomy and Genetics, University of Oxford, Sherrington Building, Parks Road, Oxford, OX1 3PT, UK
| | - David A Holdsworth
- Department of Physiology, Anatomy and Genetics, University of Oxford, Sherrington Building, Parks Road, Oxford, OX1 3PT, UK
| | - Andrew W Johnson
- Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford, OX3 9DU, UK
| | - Yu Jin Chung
- Department of Physiology, Anatomy and Genetics, University of Oxford, Sherrington Building, Parks Road, Oxford, OX1 3PT, UK
| | - M Kate Curtis
- Department of Physiology, Anatomy and Genetics, University of Oxford, Sherrington Building, Parks Road, Oxford, OX1 3PT, UK
| | - Pete J Cox
- Department of Physiology, Anatomy and Genetics, University of Oxford, Sherrington Building, Parks Road, Oxford, OX1 3PT, UK
| | - Kieran Clarke
- Department of Physiology, Anatomy and Genetics, University of Oxford, Sherrington Building, Parks Road, Oxford, OX1 3PT, UK
| | - Damian J Tyler
- Department of Physiology, Anatomy and Genetics, University of Oxford, Sherrington Building, Parks Road, Oxford, OX1 3PT, UK
| | - David J Roberts
- Nuffield Department of Clinical Laboratory Sciences, National Blood Service Oxford Centre, University of Oxford, John Radcliffe Hospital, Oxford, OX3 9BQ, UK
| | - Peter J Ratcliffe
- Nuffield Department of Medicine, University of Oxford, NDM Research Building, Old Road Campus, Headington, Oxford, OX3 7FZ, UK
- Francis Crick Institute, London, NW1 1AT, UK
| | - Keith L Dorrington
- Department of Physiology, Anatomy and Genetics, University of Oxford, Sherrington Building, Parks Road, Oxford, OX1 3PT, UK
| | - Peter A Robbins
- Department of Physiology, Anatomy and Genetics, University of Oxford, Sherrington Building, Parks Road, Oxford, OX1 3PT, UK.
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7
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Alcantara-Zapata DE, Llanos AJ, Nazzal C. High altitude exposure affects male reproductive parameters: Could it also affect the prostate?†. Biol Reprod 2021; 106:385-396. [PMID: 34725677 DOI: 10.1093/biolre/ioab205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 10/26/2021] [Indexed: 11/14/2022] Open
Abstract
Living at high altitudes and living with prostatic illness are two different conditions closely related to a hypoxic environment. People at high altitudes exposed to acute, chronic, or intermittent hypobaric hypoxia turn on several mechanisms at the system, cellular and molecular level to cope with oxygen atmosphere scarcity maintaining the oxygen homeostasis. This exposure affects the whole organism and function of many systems, such as cardiovascular, respiratory, and reproductive. On the other hand, malignant prostate is related to the scarcity of oxygen in the tissue microenvironment due to its low availability and high consumption due to the swift cell proliferation rates. Based on the literature, this similarity in the oxygen scarcity suggests that hypobaric hypoxia, and other common factors between these two conditions, could be involved in the aggravation of the pathological prostatic status. However, there is still a lack of evidence in the association of this disease in males at high altitudes. This review aims to examine the possible mechanisms that hypobaric hypoxia might negatively add to the pathological prostate function in males who live and work at high altitudes. More profound investigations of hypobaric hypoxia's direct action on the prostate could help understand this exposure's effect and prevent worse prostate illness impact in males at high altitudes.
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Affiliation(s)
| | - Aníbal J Llanos
- Laboratorio de Fisiología y Fisiopatología del Desarrollo, Programa de Fisiopatología, ICBM, Facultad de Medicina, Universidad de Chile, Santiago, Chile.,Centro Internacional de Estudios Andinos (INCAS), Universidad de Chile, Santiago, Chile
| | - Carolina Nazzal
- Department of Epidemiology. School of Public Health. Faculty of Medicine. University of Chile
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8
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Breenfeldt Andersen A, Bonne TC, Bejder J, Jung G, Ganz T, Nemeth E, Olsen NV, Huertas JR, Nordsborg NB. Effects of altitude and recombinant human erythropoietin on iron metabolism: a randomized controlled trial. Am J Physiol Regul Integr Comp Physiol 2021; 321:R152-R161. [PMID: 34160288 DOI: 10.1152/ajpregu.00070.2021] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Current markers of iron deficiency (ID), such as ferritin and hemoglobin, have shortcomings, and hepcidin and erythroferrone (ERFE) could be of clinical relevance in relation to early assessment of ID. Here, we evaluate whether exposure to altitude-induced hypoxia (2,320 m) alone, or in combination with recombinant human erythropoietin (rHuEPO) treatment, affects hepcidin and ERFE levels before alterations in routine ID biomarkers and stress erythropoiesis manifest. Two interventions were completed, each comprising a 4-wk baseline, a 4-wk intervention at either sea level or altitude, and a 4-wk follow-up. Participants (n = 39) were randomly assigned to 20 IU·kg body wt-1 rHuEPO or placebo injections every second day for 3 wk during the two intervention periods. Venous blood was collected weekly. Altitude increased ERFE (P ≤ 0.001) with no changes in hepcidin or routine iron biomarkers, making ERFE of clinical relevance as an early marker of moderate hypoxia. rHuEPO treatment at sea level induced a similar pattern of changes in ERFE (P < 0.05) and hepcidin levels (P < 0.05), demonstrating the impact of accelerated erythropoiesis and not of other hypoxia-induced mechanisms. Compared with altitude alone, concurrent rHuEPO treatment and altitude exposure induced additive changes in hepcidin (P < 0.05) and ERFE (P ≤ 0.001) parallel with increases in hematocrit (P < 0.001), demonstrating a relevant range of both hepcidin and ERFE. A poor but significant correlation between hepcidin and ERFE was found (R2 = 0.13, P < 0.001). The findings demonstrate that hepcidin and ERFE are more rapid biomarkers of changes in iron demands than routine iron markers. Finally, ERFE and hepcidin may be sensitive markers in an antidoping context.
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Affiliation(s)
| | - Thomas C Bonne
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Jacob Bejder
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Grace Jung
- Department of Medicine and Pathology, Center for Iron Disorders, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California
| | - Tomas Ganz
- Department of Medicine and Pathology, Center for Iron Disorders, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California
| | - Elizabeta Nemeth
- Department of Medicine and Pathology, Center for Iron Disorders, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California
| | - Niels Vidiendal Olsen
- Department of Neuroscience and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Jesús Rodríguez Huertas
- Department of Physiology, Faculty of Sport Sciences, Institute of Nutrition and Food Technology, Biomedical Research Centre, University of Granada, Armilla, Spain
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9
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DeLoughery TG. Clinician's Corner: Anemia at Altitude-Iron Deficiency and Other Acquired Anemias. High Alt Med Biol 2021; 22:245-248. [PMID: 33945328 DOI: 10.1089/ham.2021.0041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
DeLoughery, Thomas G. Clinician's corner: Anemia at altitude-Iron deficiency and other acquired anemias. High Alt Med Biol. 22:000-000, 2021.-Acquired anemias are common throughout the world. This article will discuss iron deficiency and other acquired causes of anemia such as inflammation and renal disease. Iron deficiency with or without anemia can detract from performance and may be a risk factor for altitude sickness. Anyone considering going to altitude should be screened for iron deficiency with a serum ferritin if they have risk factors for iron deficiency. The effects of other acquired anemias are less well defined. Several other diseases can also lead to anemia, and altitude challenges are more related to the underlying disease than to anemia.
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Affiliation(s)
- Thomas G DeLoughery
- Division of Hematology/Medical Oncology, Department of Medicine, Oregon Health and Science University, Portland, Oregon, USA.,Division of Laboratory Medicine, Department of Pathology, Oregon Health and Science University, Portland, Oregon, USA
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10
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Haase VH. Hypoxia-inducible factor-prolyl hydroxylase inhibitors in the treatment of anemia of chronic kidney disease. Kidney Int Suppl (2011) 2021; 11:8-25. [PMID: 33777492 PMCID: PMC7983025 DOI: 10.1016/j.kisu.2020.12.002] [Citation(s) in RCA: 75] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 12/18/2020] [Accepted: 12/29/2020] [Indexed: 12/11/2022] Open
Abstract
Hypoxia-inducible factor-prolyl hydroxylase domain inhibitors (HIF-PHIs) are a promising new class of orally administered drugs currently in late-stage global clinical development for the treatment of anemia of chronic kidney disease (CKD). HIF-PHIs activate the HIF oxygen-sensing pathway and are efficacious in correcting and maintaining hemoglobin levels in patients with non-dialysis- and dialysis-dependent CKD. In addition to promoting erythropoiesis through the increase in endogenous erythropoietin production, HIF-PHIs reduce hepcidin levels and modulate iron metabolism, providing increases in total iron binding capacity and transferrin levels, and potentially reducing the need for i.v. iron supplementation. Furthermore, HIF-activating drugs are predicted to have effects that extend beyond erythropoiesis. This review summarizes clinical data from current HIF-PHI trials in patients with anemia of CKD, discusses mechanisms of action and pharmacologic properties of HIF-PHIs, and deliberates over safety concerns and potential impact on anemia management in patients with CKD.
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Affiliation(s)
- Volker H. Haase
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
- Department of Molecular Physiology and Program in Cancer Biology, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
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11
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Willie CK, Patrician A, Hoiland RL, Williams AM, Gasho C, Subedi P, Anholm J, Drane A, Tymko MM, Nowak-Flück D, Plato S, McBride E, Varoli G, Binsted G, Eller LK, Reimer RA, MacLeod DB, Stembridge M, Ainslie PN. Influence of iron manipulation on hypoxic pulmonary vasoconstriction and pulmonary reactivity during ascent and acclimatization to 5050 m. J Physiol 2021; 599:1685-1708. [PMID: 33442904 DOI: 10.1113/jp281114] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Accepted: 12/16/2020] [Indexed: 12/11/2022] Open
Abstract
KEY POINTS Iron acts as a cofactor in the stabilization of the hypoxic-inducible factor family, and plays an influential role in the modulation of hypoxic pulmonary vasoconstriction. It is uncertain whether iron regulation is altered in lowlanders during either (1) ascent to high altitude, or (2) following partial acclimatization, when compared to high-altitude adapted Sherpa. During ascent to 5050 m, the rise in pulmonary artery systolic pressure (PASP) was blunted in Sherpa, compared to lowlanders; however, upon arrival to 5050 m, PASP levels were comparable in both groups, but the reduction in iron bioavailability was more prevalent in lowlanders compared to Sherpa. Following partial acclimatization to 5050 m, there were differential influences of iron status manipulation (via iron infusion or chelation) at rest and during exercise between lowlanders and Sherpa on the pulmonary vasculature. ABSTRACT To examine the adaptational role of iron bioavailability on the pulmonary vascular responses to acute and chronic hypobaric hypoxia, the haematological and cardiopulmonary profile of lowlanders and Sherpa were determined during: (1) a 9-day ascent to 5050 m (20 lowlanders; 12 Sherpa), and (2) following partial acclimatization (11 ± 4 days) to 5050 m (18 lowlanders; 20 Sherpa), where both groups received an i.v. infusion of either iron (iron (iii)-hydroxide sucrose) or an iron chelator (desferrioxamine). During ascent, there were reductions in iron status in both lowlanders and Sherpa; however, Sherpa appeared to demonstrate a more efficient capacity to mobilize stored iron, compared to lowlanders, when expressed as a Δhepcidin per unit change in either body iron or the soluble transferrin receptor index, between 3400-5050 m (P = 0.016 and P = 0.029, respectively). The rise in pulmonary artery systolic pressure (PASP) was blunted in Sherpa, compared to lowlanders during ascent; however, PASP was comparable in both groups upon arrival to 5050 m. Following partial acclimatization, despite Sherpa demonstrating a blunted hypoxic ventilatory response and greater resting hypoxaemia, they had similar hypoxic pulmonary vasoconstriction when compared to lowlanders at rest. Iron-infusion attenuated PASP in both groups at rest (P = 0.005), while chelation did not exaggerate PASP in either group at rest or during exaggerated hypoxaemia ( P I O 2 = 67 mmHg). During exercise at 25% peak wattage, PASP was only consistently elevated in Sherpa, which persisted following both iron infusion or chelation. These findings provide new evidence on the complex interplay of iron regulation on pulmonary vascular regulation during acclimatization and adaptation to high altitude.
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Affiliation(s)
- Christopher K Willie
- Centre for Heart, Lung, & Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan, Kelowna, British Columbia, Canada
| | - Alexander Patrician
- Centre for Heart, Lung, & Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan, Kelowna, British Columbia, Canada
| | - Ryan L Hoiland
- Centre for Heart, Lung, & Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan, Kelowna, British Columbia, Canada.,Department of Anaesthesiology, Pharmacology and Therapeutics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Alexandra M Williams
- Department of Cellular and Physiological Sciences, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Christopher Gasho
- Pulmonary/Critical Care Section, VA Loma Linda Healthcare System and Department of Medicine, Loma Linda University, Loma Linda, CA, USA
| | - Prajan Subedi
- Pulmonary/Critical Care Section, VA Loma Linda Healthcare System and Department of Medicine, Loma Linda University, Loma Linda, CA, USA
| | - James Anholm
- Pulmonary/Critical Care Section, VA Loma Linda Healthcare System and Department of Medicine, Loma Linda University, Loma Linda, CA, USA
| | - Aimee Drane
- Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, UK
| | - Michael M Tymko
- Centre for Heart, Lung, & Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan, Kelowna, British Columbia, Canada.,Neurovascular Health Laboratory, University of Alberta, Edmonton, Alberta, Canada
| | - Daniela Nowak-Flück
- Centre for Heart, Lung, & Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan, Kelowna, British Columbia, Canada
| | - Sawyer Plato
- Centre for Heart, Lung, & Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan, Kelowna, British Columbia, Canada
| | - Emily McBride
- Centre for Heart, Lung, & Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan, Kelowna, British Columbia, Canada
| | - Giovanfrancesco Varoli
- Centre for Heart, Lung, & Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan, Kelowna, British Columbia, Canada
| | - Gordon Binsted
- Centre for Heart, Lung, & Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan, Kelowna, British Columbia, Canada
| | - Lindsay K Eller
- Faculty of Kinesiology and Cumming School of Medicine, University of Calgary, Alberta, Canada
| | - Raylene A Reimer
- Faculty of Kinesiology and Cumming School of Medicine, University of Calgary, Alberta, Canada
| | - David B MacLeod
- Human Pharmacology & Physiology Lab, Department of Anesthesiology, Duke University Medical Center, Durham, NC, USA
| | - Michael Stembridge
- Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, UK
| | - Philip N Ainslie
- Centre for Heart, Lung, & Vascular Health, School of Health and Exercise Sciences, University of British Columbia - Okanagan, Kelowna, British Columbia, Canada
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12
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Robach P, Gammella E, Recalcati S, Girelli D, Castagna A, Roustit M, Lundby C, Lundby AK, Bouzat P, Vergès S, Séchaud G, Banco P, Uhr M, Cornu C, Sallet P, Cairo G. Induction of erythroferrone in healthy humans by micro-dose recombinant erythropoietin or high-altitude exposure. Haematologica 2021; 106:384-390. [PMID: 31919080 PMCID: PMC7849588 DOI: 10.3324/haematol.2019.233874] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 01/02/2020] [Indexed: 01/22/2023] Open
Abstract
The erythropoietin (Epo)-erythroferrone (ERFE)-hepcidin axis coordinates erythropoiesis and iron homeostasis. While mouse studies have established that Epo-induced ERFE production represses hepcidin synthesis by inhibiting hepatic BMP/SMAD signaling, evidence for the role of ERFE in humans is limited. To investigate the role of ERFE as a physiological erythroid regulator in humans, we conducted two studies. First, 24 males were given six injections of saline (placebo), recombinant Epo (rhEpo) at a dose of 20 IU/kg (micro-dose) or rhEpo at 50 IU/kg (low dose). Second, we quantified ERFE in 22 subjects exposed to high altitude (3800 m) for 15 h. In the first study, total hemoglobin mass (Hbmass) increased after low- but not after micro-dose injections, when compared to the mass after placebo injections. Serum ERFE levels were enhanced by rhEpo, remaining higher than after placebo for 48 h (micro-dose) or 72 h (low-dose) after injections. Conversely, hepcidin levels decreased when Epo and ERFE rose, before any changes in serum iron parameters occurred. In the second study, serum Epo and ERFE increased at high altitude. The present results demonstrate that in healthy humans ERFE responds to slightly increased Epo levels not associated with Hbmass expansion and downregulates hepcidin in an apparently iron-independent way. Notably, ERFE flags micro-dose Epo, thus holding promise as a novel biomarker of doping.
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Affiliation(s)
- Paul Robach
- National School for Mountains Sports, Chamonix, France
| | - Elena Gammella
- Dept Biomedical Sciences for Health, University of Milan, Italy
| | | | | | | | | | - Carsten Lundby
- Center for Physical Activity Research, University Hospital, Copenhagen, Denmark
| | | | - Pierre Bouzat
- Grenoble Alpes University Hospital, Grenoble, France
| | - Samuel Vergès
- HP2 Laboratory, U1042, Grenoble Alpes University, INSERM, Grenoble, France
| | | | | | - Mario Uhr
- Dept. Hematology Synlab-Suisse, Lugano, Switzerland
| | - Catherine Cornu
- Hospices Civils de Lyon INSERM CIC1407/UMR5558, Hôpital Louis Pradel, Bron, France
| | | | - Gaetano Cairo
- Dept Biomedical Sciences for Health, University of Milan, Italy
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13
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Comparative analysis of high altitude hypoxia induced erythropoiesis and iron homeostasis in Indian and Kyrgyz lowlander males. CURRENT RESEARCH IN BIOTECHNOLOGY 2020. [DOI: 10.1016/j.crbiot.2020.10.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
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14
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Muckenthaler MU, Mairbäurl H, Gassmann M. Iron metabolism in high-altitude residents. J Appl Physiol (1985) 2020; 129:920-925. [PMID: 32853112 DOI: 10.1152/japplphysiol.00019.2020] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Residents at high altitude cope with decreasing inspiratory oxygen partial pressure by stimulating erythropoiesis. The increase in hemoglobin levels requires high amounts of additional iron supplied from the diet. Here, we review available data on how iron metabolism adapts when living in a hypoxic environment. Our analysis reveals that long-term adaptation to high altitude enables healthy individuals to maintain their iron stores within the physiological range despite elevated requirements for erythropoiesis. However, in vulnerable populations with increased iron demand (e.g., pregnant women or exercising individuals), iron stores are less likely to be replenished quickly when living at high altitude. Future studies need to address whether different ethnicities have acquired genetic mechanisms to adapt to the elevated iron demand for erythropoiesis at high altitude.
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Affiliation(s)
- Martina U Muckenthaler
- Pediatric Oncology, Hematology & Immunology, University Hospital Heidelberg, Heidelberg, Molecular Medicine Partnership Unit, University of Heidelberg, Heidelberg, Germany.,Translational Lung Research Center Heidelberg, Member of the German Center for Lung Research, Heidelberg, Germany
| | - Heimo Mairbäurl
- Translational Lung Research Center Heidelberg, Member of the German Center for Lung Research, Heidelberg, Germany.,Translational Pneumology, University Hospital Heidelberg, Heidelberg, Germany
| | - Max Gassmann
- Institute of Veterinary Physiology, Vetsuisse Faculty, and Zurich Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland.,Universidad Peruana Cayetano Heredia, Lima, Peru
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15
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Nakanishi T, Kuragano T. Potential hazards of recent trends in liberal iron use for renal anemia. Clin Kidney J 2020; 14:59-69. [PMID: 33564406 PMCID: PMC7857828 DOI: 10.1093/ckj/sfaa117] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2020] [Accepted: 04/30/2020] [Indexed: 12/17/2022] Open
Abstract
A randomized controlled trial,the Proactive IV Iron Therapy in Haemodialysis Patients (PIVOTAL), has recently shown that a high-dose (‘proactive’) intravenous iron regimen was superior to a low-dose (‘reactive’) regimen for hemodialysis patient outcomes and overall safety. However, even in the low-dose group, a substantial amount of iron was administered to maintain serum ferritin >200 ng/mL. This type of comparison may have strongly affected the safety results. Iron has two opposite effects on erythropoiesis: it activates erythroid differentiation directly by supplying iron but inhibits it indirectly by stimulating hepcidin and enhancing oxidative stress. Hepcidin plays an essential role not only in iron homeostasis and the anemia of chronic kidney disease, but also in its complications such as atherosclerosis and infection. Its main stimulation by iron—and to a lesser degree by inflammation—should urge clinicians to avoid prescribing excessive amounts of iron. Furthermore, as serum ferritin is closely correlated with serum hepcidin and iron storage, it would seem preferable to rely mainly on serum ferritin to adjust iron administration, defining an upper limit for risk reduction. Based on our estimations, the optimal range of serum ferritin is ∼50–150 ng/mL, which is precisely within the boundaries of iron management in Japan. Considering the contrasting ranges of target ferritin levels between end-stage renal disease patients in Japan and the rest of the world, the optimal range proposed by us will probably be considered as unacceptable by nephrologists abroad. Only well-balanced, randomized controlled trials with both erythropoiesis-stimulating agents and iron will allow us to settle this controversy.
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Affiliation(s)
- Takeshi Nakanishi
- Department of Nephrology, Gojinkai Sumiyoshigawa Hospital, Nishinomiya, Japan
- Division of Kidney and Dialysis, Department of Cardiovascular and Renal Medicine, Nishinomiya, Japan
- Correspondence to: Takeshi Nakanishi; E-mail:
| | - Takahiro Kuragano
- Division of Kidney and Dialysis, Department of Cardiovascular and Renal Medicine, Nishinomiya, Japan
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16
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Lockhart SM, Saudek V, O’Rahilly S. GDF15: A Hormone Conveying Somatic Distress to the Brain. Endocr Rev 2020; 41:bnaa007. [PMID: 32310257 PMCID: PMC7299427 DOI: 10.1210/endrev/bnaa007] [Citation(s) in RCA: 112] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Accepted: 04/02/2020] [Indexed: 12/27/2022]
Abstract
GDF15 has recently gained scientific and translational prominence with the discovery that its receptor is a GFRAL-RET heterodimer of which GFRAL is expressed solely in the hindbrain. Activation of this receptor results in reduced food intake and loss of body weight and is perceived and recalled by animals as aversive. This information encourages a revised interpretation of the large body of previous research on the protein. GDF15 can be secreted by a wide variety of cell types in response to a broad range of stressors. We propose that central sensing of GDF15 via GFRAL-RET activation results in behaviors that facilitate the reduction of exposure to a noxious stimulus. The human trophoblast appears to have hijacked this signal, producing large amounts of GDF15 from early pregnancy. We speculate that this encourages avoidance of potential teratogens in pregnancy. Circulating GDF15 levels are elevated in a range of human disease states, including various forms of cachexia, and GDF15-GFRAL antagonism is emerging as a therapeutic strategy for anorexia/cachexia syndromes. Metformin elevates circulating GDF15 chronically in humans and the weight loss caused by this drug appears to be dependent on the rise in GDF15. This supports the concept that chronic activation of the GDF15-GFRAL axis has efficacy as an antiobesity agent. In this review, we examine the science of GDF15 since its identification in 1997 with our interpretation of this body of work now being assisted by a clear understanding of its highly selective central site of action.
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Affiliation(s)
- Samuel M Lockhart
- MRC Metabolic Diseases Unit, Wellcome Trust-Medical Research Council Institute of Metabolic Science, University of Cambridge, Cambridge, UK
| | - Vladimir Saudek
- MRC Metabolic Diseases Unit, Wellcome Trust-Medical Research Council Institute of Metabolic Science, University of Cambridge, Cambridge, UK
| | - Stephen O’Rahilly
- MRC Metabolic Diseases Unit, Wellcome Trust-Medical Research Council Institute of Metabolic Science, University of Cambridge, Cambridge, UK
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17
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Hennigar SR, Berryman CE, Kelley AM, Anderson BJ, Young AJ, McClung JP, Pasiakos SM. High-Altitude Acclimatization Suppresses Hepcidin Expression During Severe Energy Deficit. High Alt Med Biol 2020; 21:232-236. [PMID: 32316799 DOI: 10.1089/ham.2019.0109] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Hennigar, Stephen R., Claire E. Berryman, Alyssa M. Kelley, Bradley J. Anderson, Andrew J. Young, James P. McClung, and Stefan M. Pasiakos. High-altitude acclimatization suppresses hepcidin expression during severe energy deficit. High Alt Med Biol. 21:232-236, 2020. Background: The erythropoietic cells in the bone marrow require iron to synthesize heme for incorporation into hemoglobin. Exposure to hypoxic conditions, such as extended sojourns to high altitude (HA), results in increased erythropoiesis and an increased physiological requirement for iron. In addition to increasing iron requirements, hypoxic conditions suppress appetite and often lead to decreased energy intake. The objective of this study was to determine the combined effects of severe energy deficit and hypoxia on hepcidin and measures of iron status in lowlanders sojourning to HA. Methods: Iron status indicators and hepcidin were determined in 17 healthy male volunteers (mean ± standard deviation, age 23 ± 6 years, body mass index 27 ± 4 kg/m2) fed a controlled diet (12 ± 1.2 mg iron/day) during a 20-day sojourn to 4300 m above sea level. Results: Chronic exposure to HA during severe energy deficit increased hematocrit by 12% (p < 0.01) and decreased serum hepcidin by 37% (p < 0.01) compared with baseline. Ferritin declined by 18% (p = 0.02) and transferrin saturation and soluble transferrin receptor increased by 55% and 83%, respectively (p < 0.01 for both) compared with baseline. Conclusions: HA acclimatization suppresses hepcidin expression to increase iron availability during severe energy deficit. Registered at ClinicalTrials.gov as NCT02731066.
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Affiliation(s)
- Stephen R Hennigar
- Department of Nutrition, Food and Exercise Sciences, Florida State University, Tallahassee, Florida, USA.,Military Nutrition Division, U.S. Army Research Institute of Environmental Medicine, Natick, Massachusetts, USA.,Oak Ridge Institute for Science and Education, Belcamp, Maryland, USA
| | - Claire E Berryman
- Department of Nutrition, Food and Exercise Sciences, Florida State University, Tallahassee, Florida, USA.,Military Nutrition Division, U.S. Army Research Institute of Environmental Medicine, Natick, Massachusetts, USA.,Oak Ridge Institute for Science and Education, Belcamp, Maryland, USA
| | - Alyssa M Kelley
- Military Nutrition Division, U.S. Army Research Institute of Environmental Medicine, Natick, Massachusetts, USA.,Oak Ridge Institute for Science and Education, Belcamp, Maryland, USA
| | - Bradley J Anderson
- Military Nutrition Division, U.S. Army Research Institute of Environmental Medicine, Natick, Massachusetts, USA.,Oak Ridge Institute for Science and Education, Belcamp, Maryland, USA
| | - Andrew J Young
- Military Nutrition Division, U.S. Army Research Institute of Environmental Medicine, Natick, Massachusetts, USA.,Oak Ridge Institute for Science and Education, Belcamp, Maryland, USA
| | - James P McClung
- Military Nutrition Division, U.S. Army Research Institute of Environmental Medicine, Natick, Massachusetts, USA
| | - Stefan M Pasiakos
- Military Nutrition Division, U.S. Army Research Institute of Environmental Medicine, Natick, Massachusetts, USA
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18
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Hall R, Peeling P, Nemeth E, Bergland D, McCluskey WTP, Stellingwerff T. Single versus Split Dose of Iron Optimizes Hemoglobin Mass Gains at 2106 m Altitude. Med Sci Sports Exerc 2019; 51:751-759. [PMID: 30882751 DOI: 10.1249/mss.0000000000001847] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
PURPOSE To determine if a single versus a split equivalent daily dose of elemental iron was superior for hemoglobin mass (Hbmass) gains at altitude while minimizing gastrointestinal (GI) discomfort. METHODS Twenty-four elite runners attended a 3.1 ± 0.3 wk training camp (Flagstaff, AZ; 2106 m). A two-group design, randomized and stratified to baseline Hbmass, sex, and ferritin (>30 μ·L), was implemented daily as: 1) single dose of 1 × 200 mg (PM only, SINGLE) versus 2) split dose of 2 × 100 mg (AM and PM; SPLIT) elemental iron (ferrous fumarate). The Hbmass and venipuncture assessments were completed upon arrival and departure (±2 d) from camp for ferritin, hepcidin, and erythroferrone (ERFE) concentrations. Validated food frequency, GI distress, menstrual blood loss (MBL) and training questionnaires were implemented throughout. Univariate analysis was used to compare Hbmass, with baseline ferritin, dietary iron intake, MBL, and training volume used as covariates. RESULTS Both conditions increased Hbmass from baseline (P < 0.05), with SINGLE (867.3 ± 47.9 g) significantly higher than SPLIT (828.9 ± 48.9 g) (P = 0.048). The GI scores were worse in SINGLE for weeks 1 and 2 combined (SINGLE, 18.0 ± 6.7 points; SPLIT, 11.3 ± 6.9 points; P = 0.025); however, GI scores improved by week 3, resulting in no between-group differences (P = 0.335). Hepcidin significantly decreased over time (P = 0.043) in SINGLE, with a nonsignificant decrease evident in SPLIT (~22%). ERFE significantly decreased in both groups (~28.5%; P < 0.05). No between-group differences existed for ERFE, hepcidin, food frequency, MBL, or daily training outcomes (P > 0.05). CONCLUSIONS A single nightly 200-mg dose of elemental iron was superior to a split dose for optimizing Hbmass changes at altitude in runners over an approximately 3-wk training camp.
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Affiliation(s)
- Rebecca Hall
- Canadian Sport Institute Pacific, Vancouver & Victoria, British Columbia, CANADA
| | - Peter Peeling
- School of Human Sciences (Exercise and Sport Science), University of Western Australia, Crawley, Western Australia, AUSTRALIA.,Western Australian Institute of Sport, Mt Claremont, Western Australia, AUSTRALIA
| | - Elizabeta Nemeth
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA
| | - Dan Bergland
- Hypo2 High Performance Sport Center, Flagstaff, AZ
| | - Walter T P McCluskey
- Canadian Sport Institute Pacific, Vancouver & Victoria, British Columbia, CANADA
| | - Trent Stellingwerff
- Canadian Sport Institute Pacific, Vancouver & Victoria, British Columbia, CANADA.,Department of Exercise Science, Physical & Health Education, University of Victoria, British Columbia, CANADA
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19
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Sanghani NS, Haase VH. Hypoxia-Inducible Factor Activators in Renal Anemia: Current Clinical Experience. Adv Chronic Kidney Dis 2019; 26:253-266. [PMID: 31477256 PMCID: PMC7318915 DOI: 10.1053/j.ackd.2019.04.004] [Citation(s) in RCA: 120] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Revised: 04/26/2019] [Accepted: 04/30/2019] [Indexed: 12/14/2022]
Abstract
Prolyl hydroxylase domain oxygen sensors are dioxygenases that regulate the activity of hypoxia-inducible factor (HIF), which controls renal and hepatic erythropoietin production and coordinates erythropoiesis with iron metabolism. Small molecule inhibitors of prolyl hydroxylase domain dioxygenases (HIF-PHI [prolyl hydroxylase inhibitor]) stimulate the production of endogenous erythropoietin and improve iron metabolism resulting in efficacious anemia management in patients with CKD. Three oral HIF-PHIs-daprodustat, roxadustat, and vadadustat-have now advanced to global phase III clinical development culminating in the recent licensing of roxadustat for oral anemia therapy in China. Here, we survey current clinical experience with HIF-PHIs, discuss potential therapeutic advantages, and deliberate over safety concerns regarding long-term administration in patients with renal anemia.
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Affiliation(s)
- Neil S Sanghani
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN
| | - Volker H Haase
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN; Department of Medical Cell Biology, Uppsala Universitet, Uppsala, Sweden; Department of Molecular Physiology & Biophysics and Program in Cancer Biology, Vanderbilt University School of Medicine, Nashville, TN.
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20
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Chung YJ, Luo A, Park KC, Loonat AA, Lakhal-Littleton S, Robbins PA, Swietach P. Iron-deficiency anemia reduces cardiac contraction by downregulating RyR2 channels and suppressing SERCA pump activity. JCI Insight 2019; 4:125618. [PMID: 30779710 PMCID: PMC6483648 DOI: 10.1172/jci.insight.125618] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Accepted: 02/14/2019] [Indexed: 12/20/2022] Open
Abstract
Iron deficiency is present in ~50% of heart failure (HF) patients. Large multicenter trials have shown that treatment of iron deficiency with i.v. iron benefits HF patients, but the underlying mechanisms are not known. To investigate the actions of iron deficiency on the heart, mice were fed an iron-depleted diet, and some received i.v. ferric carboxymaltose (FCM), an iron supplementation used clinically. Iron-deficient animals became anemic and had reduced ventricular ejection fraction measured by magnetic resonance imaging. Ca2+ signaling, a pathway linked to the contractile deficit in failing hearts, was also significantly affected. Ventricular myocytes isolated from iron-deficient animals produced smaller Ca2+ transients from an elevated diastolic baseline but had unchanged sarcoplasmic reticulum (SR) Ca2+ load, trigger L-type Ca2+ current, or cytoplasmic Ca2+ buffering. Reduced fractional release from the SR was due to downregulated RyR2 channels, detected at protein and message levels. The constancy of diastolic SR Ca2+ load is explained by reduced RyR2 permeability in combination with right-shifted SERCA activity due to dephosphorylation of its regulator phospholamban. Supplementing iron levels with FCM restored normal Ca2+ signaling and ejection fraction. Thus, 2 Ca2+-handling proteins previously implicated in HF become functionally impaired in iron-deficiency anemia, but their activity is rescued by i.v. iron supplementation.
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Affiliation(s)
- Yu Jin Chung
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Antao Luo
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom.,Medical College, Wuhan University of Science and Technology, Wuhan, China
| | - Kyung Chan Park
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Aminah A Loonat
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Samira Lakhal-Littleton
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Peter A Robbins
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Pawel Swietach
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
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21
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The Functional Versatility of Transferrin Receptor 2 and Its Therapeutic Value. Pharmaceuticals (Basel) 2018; 11:ph11040115. [PMID: 30360575 PMCID: PMC6316356 DOI: 10.3390/ph11040115] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 10/19/2018] [Accepted: 10/21/2018] [Indexed: 12/11/2022] Open
Abstract
Iron homeostasis is a tightly regulated process in all living organisms because this metal is essential for cellular metabolism, but could be extremely toxic when present in excess. In mammals, there is a complex pathway devoted to iron regulation, whose key protein is hepcidin (Hepc), which is a powerful iron absorption inhibitor mainly produced by the liver. Transferrin receptor 2 (Tfr2) is one of the hepcidin regulators, and mutations in TFR2 gene are responsible for type 3 hereditary hemochromatosis (HFE3), a genetically heterogeneous disease characterized by systemic iron overload. It has been recently pointed out that Hepc production and iron regulation could be exerted also in tissues other than liver, and that Tfr2 has an extrahepatic role in iron metabolism as well. This review summarizes all the most recent data on Tfr2 extrahepatic role, taking into account the putative distinct roles of the two main Tfr2 isoforms, Tfr2α and Tfr2β. Representing Hepc modulation an effective approach to correct iron balance impairment in common human diseases, and with Tfr2 being one of its regulators, it would be worthwhile to envisage Tfr2 as a therapeutic target.
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22
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Bauer P, Zeissler S, Walscheid R, Frech T, Hillebrecht A. Acute effects of high-intensity exercise on hematological and iron metabolic parameters in elite male and female dragon boating athletes. PHYSICIAN SPORTSMED 2018; 46:335-341. [PMID: 29847191 DOI: 10.1080/00913847.2018.1482187] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
OBJECTIVE To investigate the acute effects of high-intensity exercise on blood hepcidin levels and other iron metabolic and hematological parameters in highly trained athletes of dragon boating as a sport performed in a sitting position. METHODS We conducted an exercise intervention study with a pre- and posttest blood measurement to determine the effects of high-intensity training on hematological and iron metabolic parameters in both male (n = 19) and female (n = 12) elite athletes of the German national dragon boating team. The study took place during the final training camp before the European championships. Blood samples were collected at baseline and 3 h after 3 consecutive high-intensity training bouts at the same day, each one lasting 1 h in duration. RESULTS After exercise, leukocytes, CPK, CKMB, and hepcidin levels increased significantly both in men and women. In contrast, iron concentrations decreased significantly. No gender-related differences were found. Compared with baseline, the postexercise concentrations of serum iron decreased significantly both in men [99.3 ± 46.3 to 61.2 ± 20.9 µg/dL (p < 0.001)] and in women [116.3 ± 34 to 67.1 ± 21.8 µg/dL (p < 0.001)] without a gender difference (p = 0.28). Hepcidin levels increased significantly both in men [9.1 ± 6.5 to 12.2 ± 5.8 ng/mL (p < 0.001)] and in women [8.0 ± 4.6 to 11.7 ± 5.7 ng/mL (p < 0.001)] without a significant gender difference in hepcidin changes (p = 0.34). CONCLUSIONS In conclusion, three consecutive high-intensity training bouts lead to elevated hepcidin levels and decreased iron levels in elite athletes of dragon boating. The increase in hepcidin levels may contribute to the risk of anemia in these athletes.
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Affiliation(s)
- Pascal Bauer
- a Cardiology and Angiology , University Hospital Giessen , Giessen , Germany
| | | | - Rüdiger Walscheid
- c MVZ for Laboratory Medicine and Microbiology Koblenz- Mittelrhein , Koblenz , Germany
| | - Torsten Frech
- d Sports Medicine, Justus- Liebig University Giessen , Giessen , Germany
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Baik I, Lee S, Thomas RJ, Shin C. Obstructive sleep apnea, low transferrin saturation levels, and male-pattern baldness. Int J Dermatol 2018; 58:67-74. [PMID: 30144036 DOI: 10.1111/ijd.14193] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2018] [Revised: 07/16/2018] [Accepted: 08/01/2018] [Indexed: 11/26/2022]
Abstract
BACKGROUND There are limited data on the association between obstructive sleep apnea (OSA), which is characterized by intermittent hypoxia, and male-pattern baldness (MPB). Low blood iron levels are reportedly associated with hypoxia and hair loss. This study explored a possible link among OSA, iron status, and MPB. METHODS Polysomnography (PSG) and hair assessments were conducted in a cross-sectional study including 932 men aged 46-76 years. OSA was defined as an apnea-hypopnea index ≥5 by PSG evaluation and MPB as scales from IV to VII according to the Norwood-Hamilton scale classification. Serum transferrin saturation (TSA) levels were assessed. RESULTS A total of 224 men (24%) were identified as MPB cases and 495 men (53%) as having OSA. After considering potential risk factors, OSA and other sleep-related variables were not associated with MPB. In joint analysis of OSA and family history of hair loss, men with these two factors showed a sevenfold higher multivariate odds ratio (95% confidence interval: 3.70, 12.56) for MPB than those without both of them (P < 0.05 for the interaction between OSA and family history of hair loss). TSA levels were significantly associated with MPB and OSA. OSA cases without MPB as well as MPB cases showed lower TSA levels than those with neither OSA nor MPB (P < 0.05). CONCLUSIONS These findings suggest that OSA may be a risk factor for MPB in men who have a family history of hair loss and that low serum TSA levels associated with hypoxia may be involved in a pathway linking OSA and MPB.
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Affiliation(s)
- Inkyung Baik
- Department of Foods and Nutrition, College of Science and Technology, Kookmin University, Seoul, Korea
| | - SeungKu Lee
- Institute of Human Genomic Study, Korea University Ansan Hospital, Ansan, Korea
| | - Robert J Thomas
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Beth Israel Deaconess Medical Center, Boston, MA, USA
| | - Chol Shin
- Institute of Human Genomic Study, Korea University Ansan Hospital, Ansan, Korea.,Division of Pulmonary, Sleep and Critical Care Medicine, Department of Internal Medicine, Korea University Ansan Hospital, Korea University College of Medicine, Ansan, Korea
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Liu YS, Huang H, Zhou SM, Tian HJ, Li P. Excessive Iron Availability Caused by Disorders of Interleukin-10 and Interleukin-22 Contributes to High Altitude Polycythemia. Front Physiol 2018; 9:548. [PMID: 29872401 PMCID: PMC5972294 DOI: 10.3389/fphys.2018.00548] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Accepted: 04/30/2018] [Indexed: 12/12/2022] Open
Abstract
Background: Because the pathogenesis of high altitude polycythemia (HAPC) is unclear, the aim of the present study was to explore whether abnormal iron metabolism is involved in the pathogenesis of HAPC and the possible cause. Methods: We examined the serum levels of iron, total iron binding capacity, soluble transferrin receptor (sTfR), ferritin, and hepcidin as well as erythropoietin (EPO) and inflammation-related cytokines in 20 healthy volunteers at sea level, 36 healthy high-altitude migrants, and 33 patients with HAPC. Mice that were exposed to a simulated hypoxic environment at an altitude of 5,000 m for 4 weeks received exogenous iron or intervention on cytokines, and the iron-related and hematological indices of peripheral blood and bone marrow were detected. The in vitro effects of some cytokines on hematopoietic cells were also observed. Results: Iron mobilization and utilization were enhanced in people who had lived at high altitudes for a long time. Notably, both the iron storage in ferritin and the available iron in the blood were elevated in patients with HAPC compared with the healthy high-altitude migrants. The correlation analysis indicated that the decreased hepcidin may have contributed to enhanced iron availability in HAPC, and decreased interleukin (IL)-10 and IL-22 were significantly associated with decreased hepcidin. The results of the animal experiments confirmed that a certain degree of iron redundancy may promote bone marrow erythropoiesis and peripheral red blood cell production in hypoxic mice and that decreased IL-10 and IL-22 stimulated iron mobilization during hypoxia by affecting hepcidin expression. Conclusion: These data demonstrated, for the first time, that an excess of obtainable iron caused by disordered IL-10 and IL-22 was involved in the pathogenesis of some HAPC patients. The potential benefits of iron removal and immunoregulation for the prevention and treatment of HAPC deserve further research.
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Affiliation(s)
- Yun-Sheng Liu
- Department of High Altitude Hygiene, College of High Altitude Military Medicine, Third Military Medical University, Chongqing, China.,Department of Medical Geography, College of High Altitude Military Medicine, Third Military Medical University, Chongqing, China.,Key Laboratory of High Altitude Environmental Medicine, Ministry of Education, Chongqing, China.,Key Laboratory of High Altitude Physiology and High Altitude Disease, Chinese People's Liberation Army, Chongqing, China
| | - He Huang
- Department of High Altitude Hygiene, College of High Altitude Military Medicine, Third Military Medical University, Chongqing, China.,Key Laboratory of High Altitude Environmental Medicine, Ministry of Education, Chongqing, China.,Key Laboratory of High Altitude Physiology and High Altitude Disease, Chinese People's Liberation Army, Chongqing, China
| | - Si-Min Zhou
- Department of High Altitude Hygiene, College of High Altitude Military Medicine, Third Military Medical University, Chongqing, China.,Key Laboratory of High Altitude Environmental Medicine, Ministry of Education, Chongqing, China.,Key Laboratory of High Altitude Physiology and High Altitude Disease, Chinese People's Liberation Army, Chongqing, China
| | - Huai-Jun Tian
- Department of High Altitude Hygiene, College of High Altitude Military Medicine, Third Military Medical University, Chongqing, China.,Key Laboratory of High Altitude Environmental Medicine, Ministry of Education, Chongqing, China.,Key Laboratory of High Altitude Physiology and High Altitude Disease, Chinese People's Liberation Army, Chongqing, China
| | - Peng Li
- Department of High Altitude Hygiene, College of High Altitude Military Medicine, Third Military Medical University, Chongqing, China.,Key Laboratory of High Altitude Environmental Medicine, Ministry of Education, Chongqing, China.,Key Laboratory of High Altitude Physiology and High Altitude Disease, Chinese People's Liberation Army, Chongqing, China
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Potential biomarkers of tissue hypoxia during acute hemodilutional anemia in cardiac surgery: A prospective study to assess tissue hypoxia as a mechanism of organ injury. Can J Anaesth 2018; 65:901-913. [DOI: 10.1007/s12630-018-1140-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Revised: 03/15/2018] [Accepted: 03/16/2018] [Indexed: 02/08/2023] Open
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26
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Ravasi G, Pelucchi S, Buoli Comani G, Greni F, Mariani R, Pelloni I, Bombelli S, Perego R, Barisani D, Piperno A. Hepcidin regulation in a mouse model of acute hypoxia. Eur J Haematol 2018. [PMID: 29543343 DOI: 10.1111/ejh.13062] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
OBJECTIVE During hypoxia, hepcidin expression is inhibited to allow iron mobilization to sustain erythropoietic expansion. We analyzed molecular mechanisms underlying hypoxia-induced hepcidin inhibition in an in vivo model of acute hypoxia. METHODS Mice were kept under normal or hypoxic conditions for 6 hours and 15 hours and treated with α-PDGF-BB antibody or PDGF-BB receptor inhibitor. Blood, liver, spleen, and bone marrow were collected to extract RNA and protein or to quantify EPO and PDGF-BB. mRNA and protein levels were assessed by RT-PCR and Western blot. RESULTS Hepcidin was strongly inhibited at 15 hours, and this downregulation followed erythropoiesis activation and upregulation of several growth factors. PDGF-BB, erythroferrone, GDF15, and TWSG1 were upregulated by hypoxia in the bone marrow, but not in spleen or liver. Inactivation of PDGF-BB or its receptor suppressed the hypoxia-induced hepcidin inhibition. CONCLUSION Spleen and liver are not involved in the early stages of hypoxia-induced hepcidin downregulation. Our data support the role of PDGF-BB and probably also of erythroferrone in the recruitment of iron for erythropoiesis in the hypoxia setting. The rapid normalization of all the erythroid factors against persistent hepcidin suppression suggests that other signals are involved that should be clarified in future studies.
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Affiliation(s)
- Giulia Ravasi
- School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy
| | - Sara Pelucchi
- School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy
| | - Gaia Buoli Comani
- School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy
| | - Federico Greni
- School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy
| | - Raffaella Mariani
- Centre for Disorder of Iron Metabolism, ASST-Monza - S.Gerardo Hospital, Monza, Italy
| | - Irene Pelloni
- Centre for Disorder of Iron Metabolism, ASST-Monza - S.Gerardo Hospital, Monza, Italy
| | - Silvia Bombelli
- School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy
| | - Roberto Perego
- School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy
| | - Donatella Barisani
- School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy
| | - Alberto Piperno
- School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy.,Centre for Disorder of Iron Metabolism, ASST-Monza - S.Gerardo Hospital, Monza, Italy
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Effects of an Acute Exercise Bout on Serum Hepcidin Levels. Nutrients 2018; 10:nu10020209. [PMID: 29443922 PMCID: PMC5852785 DOI: 10.3390/nu10020209] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2017] [Revised: 01/30/2018] [Accepted: 02/11/2018] [Indexed: 02/07/2023] Open
Abstract
Iron deficiency is a frequent and multifactorial disorder in the career of athletes, particularly in females. Exercise-induced disturbances in iron homeostasis produce deleterious effects on performance and adaptation to training; thus, the identification of strategies that restore or maintain iron homeostasis in athletes is required. Hepcidin is a liver-derived hormone that degrades the ferroportin transport channel, thus reducing the ability of macrophages to recycle damaged iron, and decreasing iron availability. Although it has been suggested that the circulating fraction of hepcidin increases during early post-exercise recovery (~3 h), it remains unknown how an acute exercise bout may modify the circulating expression of hepcidin. Therefore, the current review aims to determine the post-exercise expression of serum hepcidin in response to a single session of exercise. The review was carried out in the Dialnet, Elsevier, Medline, Pubmed, Scielo and SPORTDiscus databases, using hepcidin (and “exercise” or “sport” or “physical activity”) as a strategy of search. A total of 19 articles were included in the review after the application of the inclusion/exclusion criteria. This search found that a single session of endurance exercise (intervallic or continuous) at moderate or vigorous intensity (60–90% VO2peak) stimulates an increase in the circulating levels of hepcidin between 0 h and 6 h after the end of the exercise bout, peaking at ~3 h post-exercise. The magnitude of the response of hepcidin to exercise seems to be dependent on the pre-exercise status of iron (ferritin) and inflammation (IL-6). Moreover, oxygen disturbances and the activation of a hypoxia-induced factor during or after exercise may stimulate a reduction of hepcidin expression. Meanwhile, cranberry flavonoids supplementation promotes an anti-oxidant effect that may facilitate the post-exercise expression of hepcidin. Further studies are required to explore the effect of resistance exercise on hepcidin expression.
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Does Hypoxia Cause Carcinogenic Iron Accumulation in Alcoholic Liver Disease (ALD)? Cancers (Basel) 2017; 9:cancers9110145. [PMID: 29068390 PMCID: PMC5704163 DOI: 10.3390/cancers9110145] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2017] [Revised: 10/19/2017] [Accepted: 10/20/2017] [Indexed: 02/06/2023] Open
Abstract
Alcoholic liver disease (ALD) is a leading health risk worldwide. Hepatic iron overload is frequently observed in ALD patients and it is an important and independent factor for disease progression, survival, and the development of primary liver cancer (HCC). At a systemic level, iron homeostasis is controlled by the liver-secreted hormone hepcidin. Hepcidin regulation is complex and still not completely understood. It is modulated by many pathophysiological conditions associated with ALD, such as inflammation, anemia, oxidative stress/H2O2, or hypoxia. Namely, the data on hypoxia-signaling of hepcidin are conflicting, which seems to be mainly due to interpretational limitations of in vivo data and methodological challenges. Hence, it is often overlooked that hepcidin-secreting hepatocytes are physiologically exposed to 2–7% oxygen, and that key oxygen species such as H2O2 act as signaling messengers in such a hypoxic environment. Indeed, with the recently introduced glucose oxidase/catalase (GOX/CAT) system it has been possible to independently study hypoxia and H2O2 signaling. First preliminary data indicate that hypoxia enhances H2O2-mediated induction of hepcidin, pointing towards oxidases such as NADPH oxidase 4 (NOX4). We here review and discuss novel concepts of hypoxia signaling that could help to better understand hepcidin-associated iron overload in ALD.
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29
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Tashi T, Scott Reading N, Wuren T, Zhang X, Moore LG, Hu H, Tang F, Shestakova A, Lorenzo F, Burjanivova T, Koul P, Guchhait P, Wittwer CT, Julian CG, Shah B, Huff CD, Gordeuk VR, Prchal JT, Ge R. Gain-of-function EGLN1 prolyl hydroxylase (PHD2 D4E:C127S) in combination with EPAS1 (HIF-2α) polymorphism lowers hemoglobin concentration in Tibetan highlanders. J Mol Med (Berl) 2017; 95:665-670. [PMID: 28233034 DOI: 10.1007/s00109-017-1519-3] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2016] [Revised: 12/14/2016] [Accepted: 02/07/2017] [Indexed: 12/30/2022]
Abstract
Tibetans have lived at high altitude for generations and are thought to be genetically adapted to hypoxic environments. Most are protected from hypoxia-induced polycythemia, and a haplotype of EPAS1, encoding hypoxia-inducible factor (HIF-2α), has been associated with lower hemoglobin levels. We earlier reported a Tibetan-specific EGLN1 haplotype encoding PHD2 which abrogates HIF augmentation in hypoxia. We genotyped 347 Tibetan individuals from varying altitudes for both the Tibetan-specific EGLN1 haplotype and 10 candidate SNPs in the EPAS1 haplotype and correlated their association with hemoglobin levels. The effect of the EGLN1 haplotype on hemoglobin exhibited age dependency at low altitude, while at higher altitudes, it showed a trend to lower hemoglobin levels in the presence of the Tibetan-selected EPAS1 rs142764723 C/C allele. The observed gene-environment and gene-gene interactions and the moderate effect of the EGLN1 and EPAS1 haplotypes on hemoglobin indicate that other modifiers exist. It remains to be determined whether a blunting of erythropoiesis or other physiological consequences of HIF downregulation are the primary drivers of these genetic adaptations among Tibetans. KEY MESSAGE Most Tibetans are protected from polycythemia while living in high altitude. An EGLN1 co-adapted haplotype, EGLN1 c.12C>G, c.380G>C is uniquely Tibetan. The Tibetan EPAS1 haplotype has introgressed from the Denisovan genome. While EGLN1 and EPAS1 genotypes lower Hb, this study indicates additional Hb modifiers.
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Affiliation(s)
- Tsewang Tashi
- Division of Hematology, University of Utah, Salt Lake City, UT, USA
| | - N Scott Reading
- Division of Hematology, University of Utah, Salt Lake City, UT, USA
- Department of Pathology and ARUP Laboratories, University of Utah, Salt Lake City, UT, USA
| | - Tanna Wuren
- Research Center for High-Altitude Medicine, Qinghai University, Xining, China
| | - Xu Zhang
- Division of Hematology and Oncology, Department of Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Lorna G Moore
- Departments of Medicine and Obstetrics/Gynecology, University of Colorado Denver, Aurora, CO, USA
| | - Hao Hu
- MD Anderson Cancer Center, University of Texas, Houston, TX, USA
| | - Feng Tang
- Research Center for High-Altitude Medicine, Qinghai University, Xining, China
| | - Anna Shestakova
- Department of Pathology and ARUP Laboratories, University of Utah, Salt Lake City, UT, USA
| | - Felipe Lorenzo
- Division of Hematology, University of Utah, Salt Lake City, UT, USA
| | - Tatiana Burjanivova
- Division of Hematology, University of Utah, Salt Lake City, UT, USA
- Department of Molecular Biology, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, Bratislava, Slovakia
| | - Parvaiz Koul
- Sher-i-Kashmir Institute of Medical Sciences, Srinagar, India
| | | | - Carl T Wittwer
- Department of Pathology and ARUP Laboratories, University of Utah, Salt Lake City, UT, USA
| | - Colleen G Julian
- Departments of Medicine and Obstetrics/Gynecology, University of Colorado Denver, Aurora, CO, USA
| | - Binal Shah
- Division of Hematology and Oncology, Department of Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Chad D Huff
- MD Anderson Cancer Center, University of Texas, Houston, TX, USA
| | - Victor R Gordeuk
- Division of Hematology and Oncology, Department of Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Josef T Prchal
- Division of Hematology, University of Utah, Salt Lake City, UT, USA.
- Department of Pathology and ARUP Laboratories, University of Utah, Salt Lake City, UT, USA.
- Department of Pathophysiology and 1st Department of Medicine, 1st Faculty Medicine, Charles University in Prague, Prague, Czech Republic.
- Hematology, SOM 5C310, University of Utah School of Medicine, Salt Lake City, UT, 84132-2408, USA.
| | - RiLi Ge
- Research Center for High-Altitude Medicine, Qinghai University, Xining, China.
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Reduced cancer mortality at high altitude: The role of glucose, lipids, iron and physical activity. Exp Cell Res 2017; 356:209-216. [PMID: 28344053 DOI: 10.1016/j.yexcr.2017.03.048] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2017] [Accepted: 03/22/2017] [Indexed: 12/21/2022]
Abstract
Residency at high altitude (HA) demands adaptation to challenging environmental conditions with hypobaric hypoxia being the most important one. Epidemiological and experimental data suggest that chronic exposure to HA reduces cancer mortality and lowers prevalence of metabolic disorders like diabetes and obesity implying that adaption to HA modifies a broad spectrum of physiological, metabolic and cellular programs with a generally beneficial outcome for humans. However, the complexity of multiple, potentially tumor-suppressive pathways at HA impedes the understanding of mechanisms leading to reduced cancer mortality. Many adaptive processes at HA are tightly interconnected and thus it cannot be ruled out that the entirety or at least some of the HA-related alterations act in concert to reduce cancer mortality. In this review we discuss tumor formation as a concept of competition between healthy and cancer cells with improved fitness - and therefore higher competitiveness - of healthy cells at high altitude. We discuss HA-related changes in glucose, lipid and iron metabolism that may have an impact on tumorigenesis. Additionally, we discuss two parameters with a strong impact on tumorigenesis, namely drug metabolism and physical activity, to underpin their potential contribution to HA-dependent reduced cancer mortality. Future studies are needed to unravel why cancer mortality is reduced at HA and how this knowledge might be used to prevent and to treat cancer patients.
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Li Y, Yu P, Chang SY, Wu Q, Yu P, Xie C, Wu W, Zhao B, Gao G, Chang YZ. Hypobaric Hypoxia Regulates Brain Iron Homeostasis in Rats. J Cell Biochem 2016; 118:1596-1605. [PMID: 27925282 DOI: 10.1002/jcb.25822] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Accepted: 11/30/2016] [Indexed: 12/18/2022]
Abstract
Disruption of iron homeostasis in brain has been found to be closely involved in several neurodegenerative diseases. Recent studies have reported that appropriate intermittent hypobaric hypoxia played a protective role in brain injury caused by acute hypoxia. However, the mechanisms of this protective effect have not been fully understood. In this study, Sprague-Dawley (SD) rat models were developed by hypobaric hypoxia treatment in an altitude chamber, and the iron level and iron related protein levels were determined in rat brain after 4 weeks of treatment. We found that the iron levels significantly decreased in the cortex and hippocampus of rat brain as compared to that of the control rats without hypobaric hypoxia treatment. The expression levels of iron storage protein L-ferritin and iron transport proteins, including transferrin receptor-1 (TfR1), divalent metal transporter 1 (DMT1), and ferroportin1 (FPN1), were also altered. Further studies found that the iron regulatory protein 2 (IRP2) played a dominant regulatory role in the changes of iron hemostasis, whereas iron regulatory protein 1 (IRP1) mainly acted as cis-aconitase. These results, for the first time, showed the alteration of iron metabolism during hypobaric hypoxia in rat models, which link the potential neuroprotective role of hypobaric hypoxia treatment to the decreased iron level in brain. This may provide insight into the treatment of iron-overloaded neurodegenerative diseases. J. Cell. Biochem. 118: 1596-1605, 2017. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Yaru Li
- Laboratory of Molecular Iron Metabolism, Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology of Hebei Province, College of Life Science, Hebei Normal University, Shijiazhuang 050024, Hebei Province, China
| | - Peng Yu
- Laboratory of Molecular Iron Metabolism, Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology of Hebei Province, College of Life Science, Hebei Normal University, Shijiazhuang 050024, Hebei Province, China
| | - Shi-Yang Chang
- Laboratory of Molecular Iron Metabolism, Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology of Hebei Province, College of Life Science, Hebei Normal University, Shijiazhuang 050024, Hebei Province, China
| | - Qiong Wu
- Laboratory of Molecular Iron Metabolism, Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology of Hebei Province, College of Life Science, Hebei Normal University, Shijiazhuang 050024, Hebei Province, China
| | - Panpan Yu
- Laboratory of Molecular Iron Metabolism, Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology of Hebei Province, College of Life Science, Hebei Normal University, Shijiazhuang 050024, Hebei Province, China
| | - Congcong Xie
- Laboratory of Molecular Iron Metabolism, Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology of Hebei Province, College of Life Science, Hebei Normal University, Shijiazhuang 050024, Hebei Province, China
| | - Wenyue Wu
- Laboratory of Molecular Iron Metabolism, Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology of Hebei Province, College of Life Science, Hebei Normal University, Shijiazhuang 050024, Hebei Province, China
| | - Baolu Zhao
- Laboratory of Molecular Iron Metabolism, Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology of Hebei Province, College of Life Science, Hebei Normal University, Shijiazhuang 050024, Hebei Province, China
| | - Guofen Gao
- Laboratory of Molecular Iron Metabolism, Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology of Hebei Province, College of Life Science, Hebei Normal University, Shijiazhuang 050024, Hebei Province, China
| | - Yan-Zhong Chang
- Laboratory of Molecular Iron Metabolism, Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology of Hebei Province, College of Life Science, Hebei Normal University, Shijiazhuang 050024, Hebei Province, China
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Besarab A, Szczech L. What are the Considerations in Balancing Benefits and Risks in Iron Treatment?: How Hypoxia-Inducible Factor-Prolyl Hydroxylase Inhibitors May Change Iron Management in End-Stage Renal Disease. Semin Dial 2016; 30:29-31. [PMID: 27699882 DOI: 10.1111/sdi.12553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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34
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Schmid H, Jelkmann W. Investigational therapies for renal disease-induced anemia. Expert Opin Investig Drugs 2016; 25:901-16. [DOI: 10.1080/13543784.2016.1182981] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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Abstract
Hepcidin is the master regulator of systemic iron homeostasis, facilitating iron balance by controlling intestinal iron absorption and recycling. Hepcidin levels are suppressed when erythropoiesis is stimulated, for example following acute blood loss, appropriately enhancing cellular iron export to the plasma to support production of new red blood cells. However, persistent increased and ineffective erythropoiesis, for example in thalassemia, results in sustained elevations in iron absorption, which cause iron overload with associated organ toxicities. The ligands, receptors, and canonical pathways by which iron loading and inflammation upregulate hepcidin expression have been largely established. However, although several mechanisms have been proposed, the means by which erythropoiesis causes hepcidin suppression have been unclear. The erythroid-derived hormone erythroferrone appears to be a convincing candidate for the link between increased erythropoiesis and hepcidin suppression. If confirmed to be clinically and physiologically relevant in humans, potentiation or inhibition of erythroferrone activity could be a crucial pharmaceutical strategy.
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Affiliation(s)
- Sant-Rayn Pasricha
- Medical Research Council (MRC) Human Immunology Unit, MRC Weatherall Institute for Molecular Medicine, University of Oxford, Oxford OX3 9DS, United Kingdom;
| | - Kirsty McHugh
- Jenner Institute, University of Oxford, Oxford OX3 7DQ, United Kingdom
| | - Hal Drakesmith
- Medical Research Council (MRC) Human Immunology Unit, MRC Weatherall Institute for Molecular Medicine, University of Oxford, Oxford OX3 9DS, United Kingdom;
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Frise MC, Cheng HY, Nickol AH, Curtis MK, Pollard KA, Roberts DJ, Ratcliffe PJ, Dorrington KL, Robbins PA. Clinical iron deficiency disturbs normal human responses to hypoxia. J Clin Invest 2016; 126:2139-50. [PMID: 27140401 PMCID: PMC4887172 DOI: 10.1172/jci85715] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 03/10/2016] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Iron bioavailability has been identified as a factor that influences cellular hypoxia sensing, putatively via an action on the hypoxia-inducible factor (HIF) pathway. We therefore hypothesized that clinical iron deficiency would disturb integrated human responses to hypoxia. METHODS We performed a prospective, controlled, observational study of the effects of iron status on hypoxic pulmonary hypertension. Individuals with absolute iron deficiency (ID) and an iron-replete (IR) control group were exposed to two 6-hour periods of isocapnic hypoxia. The second hypoxic exposure was preceded by i.v. infusion of iron. Pulmonary artery systolic pressure (PASP) was serially assessed with Doppler echocardiography. RESULTS Thirteen ID individuals completed the study and were age- and sex-matched with controls. PASP did not differ by group or study day before each hypoxic exposure. During the first 6-hour hypoxic exposure, the rise in PASP was 6.2 mmHg greater in the ID group (absolute rises 16.1 and 10.7 mmHg, respectively; 95% CI for difference, 2.7-9.7 mmHg, P = 0.001). Intravenous iron attenuated the PASP rise in both groups; however, the effect was greater in ID participants than in controls (absolute reductions 11.1 and 6.8 mmHg, respectively; 95% CI for difference in change, -8.3 to -0.3 mmHg, P = 0.035). Serum erythropoietin responses to hypoxia also differed between groups. CONCLUSION Clinical iron deficiency disturbs normal responses to hypoxia, as evidenced by exaggerated hypoxic pulmonary hypertension that is reversed by subsequent iron administration. Disturbed hypoxia sensing and signaling provides a mechanism through which iron deficiency may be detrimental to human health. TRIAL REGISTRATION ClinicalTrials.gov (NCT01847352). FUNDING M.C. Frise is the recipient of a British Heart Foundation Clinical Research Training Fellowship (FS/14/48/30828). K.L. Dorrington is supported by the Dunhill Medical Trust (R178/1110). D.J. Roberts was supported by R&D funding from National Health Service (NHS) Blood and Transplant and a National Institute for Health Research (NIHR) Programme grant (RP-PG-0310-1004). This research was funded by the NIHR Oxford Biomedical Research Centre Programme.
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Affiliation(s)
- Matthew C. Frise
- University of Oxford, Department of Physiology, Anatomy and Genetics, Oxford, United Kingdom
| | - Hung-Yuan Cheng
- University of Oxford, Department of Physiology, Anatomy and Genetics, Oxford, United Kingdom
| | - Annabel H. Nickol
- Oxford University Hospitals NHS Foundation Trust, Oxford Centre for Respiratory Medicine, Churchill Hospital, Oxford, United Kingdom
| | - M. Kate Curtis
- University of Oxford, Department of Physiology, Anatomy and Genetics, Oxford, United Kingdom
| | - Karen A. Pollard
- University of Oxford, Department of Physiology, Anatomy and Genetics, Oxford, United Kingdom
| | - David J. Roberts
- University of Oxford, Nuffield Department of Clinical Laboratory Sciences, and National Health Service Blood and Transplant Oxford Centre, John Radcliffe Hospital, Oxford, United Kingdom
| | - Peter J. Ratcliffe
- University of Oxford, Nuffield Department of Medicine, Henry Wellcome Building for Molecular Physiology, Old Road Campus, Headington, Oxford, United Kingdom
| | - Keith L. Dorrington
- University of Oxford, Department of Physiology, Anatomy and Genetics, Oxford, United Kingdom
| | - Peter A. Robbins
- University of Oxford, Department of Physiology, Anatomy and Genetics, Oxford, United Kingdom
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Talbot NP, Smith TG, Lakhal-Littleton S, Gülsever C, Rivera-Ch M, Dorrington KL, Mole DR, Robbins PA. Suppression of plasma hepcidin by venesection during steady-state hypoxia. Blood 2016; 127:1206-7. [PMID: 26773043 DOI: 10.1182/blood-2015-05-647404] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Affiliation(s)
- Nick P Talbot
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Thomas G Smith
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Samira Lakhal-Littleton
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Cafer Gülsever
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Maria Rivera-Ch
- Laboratory of High Altitude Adaptation, Faculty of Sciences and Philosophy, Universidad Peruana Cayetano Heredia, Lima, Peru; and
| | - Keith L Dorrington
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - David R Mole
- Henry Wellcome Building for Molecular Physiology, University of Oxford, Oxford, United Kingdom
| | - Peter A Robbins
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
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Li X, Rhee DK, Malhotra R, Mayeur C, Hurst LA, Ager E, Shelton G, Kramer Y, McCulloh D, Keefe D, Bloch KD, Bloch DB, Peterson RT. Progesterone receptor membrane component-1 regulates hepcidin biosynthesis. J Clin Invest 2015; 126:389-401. [PMID: 26657863 DOI: 10.1172/jci83831] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Accepted: 11/05/2015] [Indexed: 01/19/2023] Open
Abstract
Iron homeostasis is tightly regulated by the membrane iron exporter ferroportin and its regulatory peptide hormone hepcidin. The hepcidin/ferroportin axis is considered a promising therapeutic target for the treatment of diseases of iron overload or deficiency. Here, we conducted a chemical screen in zebrafish to identify small molecules that decrease ferroportin protein levels. The chemical screen led to the identification of 3 steroid molecules, epitiostanol, progesterone, and mifepristone, which decrease ferroportin levels by increasing the biosynthesis of hepcidin. These hepcidin-inducing steroids (HISs) did not activate known hepcidin-inducing pathways, including the BMP and JAK/STAT3 pathways. Progesterone receptor membrane component-1 (PGRMC1) was required for HIS-dependent increases in hepcidin biosynthesis, as PGRMC1 depletion in cultured hepatoma cells and zebrafish blocked the ability of HISs to increase hepcidin mRNA levels. Neutralizing antibodies directed against PGRMC1 attenuated the ability of HISs to induce hepcidin gene expression. Inhibiting the kinases of the SRC family, which are downstream of PGRMC1, blocked the ability of HISs to increase hepcidin mRNA levels. Furthermore, HIS treatment increased hepcidin biosynthesis in mice and humans. Together, these data indicate that PGRMC1 regulates hepcidin gene expression through an evolutionarily conserved mechanism. These studies have identified drug candidates and potential therapeutic targets for the treatment of diseases of abnormal iron metabolism.
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Lotfi R, Kroll C, Plonné D, Jahrsdörfer B, Schrezenmeier H. Hepcidin/Ferritin Quotient Helps to Predict Spontaneous Recovery from Iron Loss following Blood Donation. Transfus Med Hemother 2015; 42:390-5. [PMID: 26733771 DOI: 10.1159/000440825] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Accepted: 05/06/2015] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Iron supplementation is generally recommended for blood donors even though there are inter-individual differences in iron homeostasis. METHODS Ferritin levels of repeat donors were compared with first-time donors, retrospectively. Prospectively, we tested 27 male repeat donors for the following parameters at the day of blood donation as well as 1, 3, 7, 10, and 56 days thereafter: ferritin, hepcidin, transferrin, transferrin receptor, hemoglobin, erythropoietin, reticulocytes, hemoglobin in reticulocyte, twisted gastrulation protein homolog 1, and growth differentiation factor-15. RESULTS 56 days after blood donation, donors' average ferritin dropped to 55% (range 30-100%) compared to the initial value. Of all tested parameters hepcidin showed the highest and most significant changes beginning 1 day after donation and lasting for the whole period of 56 days. Along with ferritin, there was a high variation in hepcidin levels indicating inter-individual differences in hepcidin response to iron loss. Donors with a hepcidin/ferritin quotient < 0.3 regained 60% of their initial ferritin after 56 days, while those with a quotient ≥ 0.3 reached less than 50%. CONCLUSION As hepcidin appears to integrate erythropoietic and iron-loading signals, clinical measurement of hepcidin (together with the hepcidin-ferritin ratio) may become a useful indicator of erythropoiesis and iron kinetics.
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Affiliation(s)
- Ramin Lotfi
- Institute for Transfusion Medicine, University Hospital Ulm, Ulm, Germany; Institute for Clinical Transfusion Medicine and Immunogenetics Ulm, German Red Cross Blood Services Baden-Württemberg-Hessen, Ulm, Germany
| | - Christine Kroll
- Institute for Clinical Transfusion Medicine and Immunogenetics Ulm, German Red Cross Blood Services Baden-Württemberg-Hessen, Ulm, Germany
| | - Dietmar Plonné
- MVZ Humangenetik Ulm, Abteilung Laboratoriumsmedizin, Ulm, Germany
| | - Bernd Jahrsdörfer
- Institute for Transfusion Medicine, University Hospital Ulm, Ulm, Germany; Institute for Clinical Transfusion Medicine and Immunogenetics Ulm, German Red Cross Blood Services Baden-Württemberg-Hessen, Ulm, Germany
| | - Hubert Schrezenmeier
- Institute for Transfusion Medicine, University Hospital Ulm, Ulm, Germany; Institute for Clinical Transfusion Medicine and Immunogenetics Ulm, German Red Cross Blood Services Baden-Württemberg-Hessen, Ulm, Germany
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Govus AD, Garvican-Lewis LA, Abbiss CR, Peeling P, Gore CJ. Pre-Altitude Serum Ferritin Levels and Daily Oral Iron Supplement Dose Mediate Iron Parameter and Hemoglobin Mass Responses to Altitude Exposure. PLoS One 2015; 10:e0135120. [PMID: 26263553 PMCID: PMC4532405 DOI: 10.1371/journal.pone.0135120] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Accepted: 07/17/2015] [Indexed: 11/18/2022] Open
Abstract
PURPOSE To investigate the influence of daily oral iron supplementation on changes in hemoglobin mass (Hbmass) and iron parameters after 2-4 weeks of moderate altitude exposure. METHODS Hematological data collected from 178 athletes (98 males, 80 females) exposed to moderate altitude (1,350-3,000 m) were analysed using linear regression to determine how altitude exposure combined with oral iron supplementation influenced Hbmass, total iron incorporation (TII) and blood iron parameters [ferritin and transferrin saturation (TSAT)]. RESULTS Altitude exposure (mean ± s: 21 ± 3 days) increased Hbmass by 1.1% [-0.4, 2.6], 3.3% [1.7, 4.8], and 4.0% [2.0, 6.1] from pre-altitude levels in athletes who ingested nil, 105 mg and 210 mg respectively, of oral iron supplement daily. Serum ferritin levels decreased by -33.2% [-46.9, -15.9] and 13.8% [-32.2, 9.7] from pre-altitude levels in athletes who supplemented with nil and 105 mg of oral iron supplement daily, but increased by 36.8% [1.3, 84.8] in athletes supplemented with 210 mg of oral iron daily. Finally, athletes who ingested either 105 mg or 210 mg of oral iron supplement daily had a greater TII compared with non-supplemented athletes (0 versus 105 mg: effect size (d) = -1.88 [-2.56, -1.17]; 0 versus 210 mg: effect size (d) = -2.87 [-3.88, -1.66]). CONCLUSION Oral iron supplementation during 2-4 weeks of moderate altitude exposure may enhance Hbmass production and assist the maintenance of iron balance in some athletes with low pre-altitude iron stores.
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Affiliation(s)
- Andrew D. Govus
- Centre for Exercise and Sports Science Research, School of Exercise and Health Science, Edith Cowan University, Joondalup, WA, Australia
- * E-mail:
| | - Laura A. Garvican-Lewis
- Department of Physiology, Australian Institute of Sport, Bruce, ACT, Australia
- Research Institute for Sport and Exercise, University of Canberra, Bruce, ACT, Australia
| | - Chris R. Abbiss
- Centre for Exercise and Sports Science Research, School of Exercise and Health Science, Edith Cowan University, Joondalup, WA, Australia
| | - Peter Peeling
- School of Sport Science, Exercise & Health, University of Western Australia, Crawley, WA, Australia
| | - Christopher J. Gore
- Department of Physiology, Australian Institute of Sport, Bruce, ACT, Australia
- Exercise Physiology Laboratory, Flinders University, Bedford Park, SA, Australia
- Research Institute for Sport and Exercise, University of Canberra, Bruce, ACT, Australia
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41
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Gassmann M, Muckenthaler MU. Adaptation of iron requirement to hypoxic conditions at high altitude. J Appl Physiol (1985) 2015; 119:1432-40. [PMID: 26183475 DOI: 10.1152/japplphysiol.00248.2015] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Accepted: 07/10/2015] [Indexed: 12/12/2022] Open
Abstract
Adequate acclimatization time to enable adjustment to hypoxic conditions is one of the most important aspects for mountaineers ascending to high altitude. Accordingly, most reviews emphasize mechanisms that cope with reduced oxygen supply. However, during sojourns to high altitude adjustment to elevated iron demand is equally critical. Thus in this review we focus on the interaction between oxygen and iron homeostasis. We review the role of iron 1) in the oxygen sensing process and erythropoietin (Epo) synthesis, 2) in gene expression control mediated by the hypoxia-inducible factor-2 (HIF-2), and 3) as an oxygen carrier in hemoglobin, myoglobin, and cytochromes. The blood hormone Epo that is abundantly expressed by the kidney under hypoxic conditions stimulates erythropoiesis in the bone marrow, a process requiring high iron levels. To ensure that sufficient iron is provided, Epo-controlled erythroferrone that is expressed in erythroid precursor cells acts in the liver to reduce expression of the iron hormone hepcidin. Consequently, suppression of hepcidin allows for elevated iron release from storage organs and enhanced absorption of dietary iron by enterocytes. As recently observed in sojourners at high altitude, however, iron uptake may be hampered by reduced appetite and gastrointestinal bleeding. Reduced iron availability, as observed in a hypoxic mountaineer, enhances hypoxia-induced pulmonary hypertension and may contribute to other hypoxia-related diseases. Overall, adequate systemic iron availability is an important prerequisite to adjust to high-altitude hypoxia and may have additional implications for disease-related hypoxic conditions.
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Affiliation(s)
- Max Gassmann
- Institute of Veterinary Physiology, Vetsuisse Faculty, and Zurich Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland, and Universidad Peruana Cayetano Heredia, Lima, Peru; and
| | - Martina U Muckenthaler
- Pediatric Oncology, Hematology and Immunology, University Hospital Heidelberg, Molecular Medicine Partnership Unit, University of Heidelberg, Translational Lung Research Center Heidelberg, and German Center for Lung Research, Heidelberg, Germany
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42
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BURDEN RICHARDJ, POLLOCK NOEL, WHYTE GREGORYP, RICHARDS TOBY, MOORE BRIAN, BUSBRIDGE MARK, SRAI SURJITK, OTTO JAMES, PEDLAR CHARLESR. Effect of Intravenous Iron on Aerobic Capacity and Iron Metabolism in Elite Athletes. Med Sci Sports Exerc 2015; 47:1399-407. [DOI: 10.1249/mss.0000000000000568] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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Frise MC, Robbins PA. Iron, oxygen, and the pulmonary circulation. J Appl Physiol (1985) 2015; 119:1421-31. [PMID: 26066825 PMCID: PMC4683351 DOI: 10.1152/japplphysiol.00179.2015] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Accepted: 06/05/2015] [Indexed: 12/24/2022] Open
Abstract
The human pulmonary vasculature vasoconstricts in response to a reduction in alveolar oxygen tension, a phenomenon termed hypoxic pulmonary vasoconstriction (HPV). This review describes the time course of this behavior, which occurs in distinct phases, and then explores the importance for HPV of the hypoxia-inducible factor (HIF) pathway. Next, the HIF-hydroxylase enzymes that act as molecular oxygen sensors within the HIF pathway are discussed. These enzymes are particularly sensitive to intracellular iron availability, which confers iron-sensing properties on the HIF pathway. Human studies of iron chelation and supplementation are then reviewed. These demonstrate that the iron sensitivity of the HIF pathway evident from in vitro experiments is relevant to human pulmonary vascular physiology. Next, the importance of iron status in high-altitude illness and chronic cardiopulmonary disease is explored, and the therapeutic potential of intravenous iron discussed. The review concludes by highlighting some further complexities that arise from interactions between the HIF pathway and other intracellular iron-sensing mechanisms.
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Affiliation(s)
- Matthew C Frise
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Peter A Robbins
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
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De Ferrari A, Miranda JJ, Gilman RH, Dávila-Román VG, León-Velarde F, Rivera-Ch M, Huicho L, Bernabé-Ortiz A, Wise RA, Checkley W. Prevalence, clinical profile, iron status, and subject-specific traits for excessive erythrocytosis in andean adults living permanently at 3,825 meters above sea level. Chest 2015; 146:1327-1336. [PMID: 24874587 DOI: 10.1378/chest.14-0298] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
BACKGROUND Excessive erythrocytosis (EE) is a prevalent condition in populations living at high altitudes (> 2,500 m above sea level). Few large population-based studies have explored the association between EE and multiple subject-specific traits including oxygen saturation, iron status indicators, and pulmonary function. METHODS We enrolled a sex-stratified and age-stratified sample of 1,065 high-altitude residents aged ≥ 35 years from Puno, Peru (3,825 m above sea level) and conducted a standardized questionnaire and physical examination that included spirometry, pulse oximetry, and a blood sample for multiple clinical markers. Our primary objectives were to estimate the prevalence of EE, characterize the clinical profile and iron status indicators of subjects with EE, and describe subject-specific traits associated with EE. RESULTS Overall prevalence of EE was 4.5% (95% CI, 3.3%-6.0%). Oxygen saturation was significantly lower among EE than non-EE group subjects (85.3% vs 90.1%, P < .001) but no difference was found in iron status indicators between both groups (P > .09 for all values). In multivariable logistic regression, we found that age ≥ 65 years (OR = 2.45, 95% CI, 1.16-5.09), male sex (3.86, 1.78-9.08), having metabolic syndrome (2.66, 1.27-5.75) or being overweight (5.20, 1.95-16.77), pulse oximetry < 85% (14.90, 6.43-34.90), and % predicted FVC < 80% (13.62, 4.40-41.80) were strongly associated with EE. Attributable fractions for EE were greatest for being overweight (26.7%), followed by male sex (21.5%), pulse oximetry < 85% (16.4%), having metabolic syndrome (14.4%), and % predicted FVC < 80% (9.3%). CONCLUSIONS We found a lower prevalence of EE than in previous reports in the Peruvian Andes. Although the presence of hypoxemia and decreased vital capacity were strongly associated with excessive erythrocytosis, being overweight or having metabolic syndrome were associated with an important fraction of cases in our study population.
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Affiliation(s)
- Aldo De Ferrari
- From the Division of Pulmonary and Critical Care, School of Medicine, Johns Hopkins University, Baltimore, MD
| | - J Jaime Miranda
- CRONICAS Centre of Excellence for Chronic Diseases, Universidad Peruana Cayetano Heredia, Lima, Peru; Departamento de Medicina, Escuela de Medicina, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Robert H Gilman
- CRONICAS Centre of Excellence for Chronic Diseases, Universidad Peruana Cayetano Heredia, Lima, Peru; Departamento de Medicina, Escuela de Medicina, Universidad Peruana Cayetano Heredia, Lima, Peru; Program in Global Disease Epidemiology and Control, Department of International Health, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD
| | - Victor G Dávila-Román
- Cardiovascular Imaging and Clinical Research Core Laboratory, Cardiovascular Division, School of Medicine, Washington University in St. Louis, St. Louis, MO
| | - Fabiola León-Velarde
- Departamento de Ciencias Biológicas y Fisiológicas, Laboratorio de Adaptación a la Altura, Laboratorios de Investigación y Desarrollo, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Maria Rivera-Ch
- Departamento de Ciencias Biológicas y Fisiológicas, Laboratorio de Adaptación a la Altura, Laboratorios de Investigación y Desarrollo, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Luis Huicho
- Departamento de Ciencias Biológicas y Fisiológicas, Laboratorio de Adaptación a la Altura, Laboratorios de Investigación y Desarrollo, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Antonio Bernabé-Ortiz
- CRONICAS Centre of Excellence for Chronic Diseases, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Robert A Wise
- From the Division of Pulmonary and Critical Care, School of Medicine, Johns Hopkins University, Baltimore, MD
| | - William Checkley
- From the Division of Pulmonary and Critical Care, School of Medicine, Johns Hopkins University, Baltimore, MD; CRONICAS Centre of Excellence for Chronic Diseases, Universidad Peruana Cayetano Heredia, Lima, Peru; Departamento de Medicina, Escuela de Medicina, Universidad Peruana Cayetano Heredia, Lima, Peru.
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Altamura S, Bärtsch P, Dehnert C, Maggiorini M, Weiss G, Theurl I, Muckenthaler MU, Mairbäurl H. Increased hepcidin levels in high-altitude pulmonary edema. J Appl Physiol (1985) 2014; 118:292-8. [PMID: 25525212 DOI: 10.1152/japplphysiol.00940.2014] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Low iron availability enhances hypoxic pulmonary vasoconstriction (HPV). Considering that reduced serum iron is caused by increased erythropoiesis, insufficient reabsorption, or elevated hepcidin levels, one might speculate that exaggerated HPV in high-altitude pulmonary edema (HAPE) is related to low serum iron. To test this notion we measured serum iron and hepcidin in blood samples obtained in previously published studies at low altitude and during 2 days at 4,559 m (HA1, HA2) from controls, individuals with HAPE, and HAPE-susceptible individuals where prophylactic dexamethasone and tadalafil prevented HAPE. As reported, at 4,559 m pulmonary arterial pressure was increased in healthy volunteers but reached higher levels in HAPE. Serum iron levels were reduced in all groups at HA2. Hepcidin levels were reduced in all groups at HA1 and HA2 except in HAPE, where hepcidin was decreased at HA1 but unexpectedly high at HA2. Elevated hepcidin in HAPE correlated with increased IL-6 at HA2, suggesting that an inflammatory response related to HAPE contributes to increased hepcidin. Likewise, platelet-derived growth factor, a regulator of hepcidin, was increased at HA1 and HA2 in controls but not in HAPE, suggesting that hypoxia-controlled factors that regulate serum iron are inappropriately expressed in HAPE. In summary, we found that HAPE is associated with inappropriate expression of hepcidin without inducing expected changes in serum iron within 2 days at HA, likely due to too short time. Although hepcidin expression is uncoupled from serum iron availability and hypoxia in individuals developing HAPE, our findings indicate that serum iron is not related with exaggerated HPV.
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Affiliation(s)
- Sandro Altamura
- Pediatric Oncology, Hematology & Immunology, University Hospital Heidelberg, Germany
| | - Peter Bärtsch
- Medical Clinic VII, Sports Medicine, University Hospital Heidelberg, Germany
| | - Christoph Dehnert
- Medical Clinic VII, Sports Medicine, University Hospital Heidelberg, Germany
| | - Marco Maggiorini
- Intensive Care Unit, Internal Medicine, University Hospital Zürich, Switzerland; and
| | - Günter Weiss
- Department of Internal Medicine VI, Clinical Immunology and Infectious Diseases, Medical University of Innsbruck, Austria
| | - Igor Theurl
- Department of Internal Medicine VI, Clinical Immunology and Infectious Diseases, Medical University of Innsbruck, Austria
| | | | - Heimo Mairbäurl
- Medical Clinic VII, Sports Medicine, University Hospital Heidelberg, Germany;
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Hepcidin is suppressed by erythropoiesis in hemoglobin E β-thalassemia and β-thalassemia trait. Blood 2014; 125:873-80. [PMID: 25519750 DOI: 10.1182/blood-2014-10-606491] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Hemoglobin E (HbE) β-thalassemia is the most common severe thalassemia syndrome across Asia, and millions of people are carriers. Clinical heterogeneity in HbE β-thalassemia is incompletely explained by genotype, and the interaction of phenotypic variation with hepcidin is unknown. The effect of thalassemia carriage on hepcidin is also unknown, but it could be relevant for iron supplementation programs aimed at combating anemia. In 62 of 69 Sri Lankan patients with HbE β-thalassemia with moderate or severe phenotype, hepcidin was suppressed, and overall hepcidin inversely correlated with iron accumulation. On segregating by phenotype, there were no differences in hepcidin, erythropoiesis, or hemoglobin between severe or moderate disease, but multiple linear regression showed that erythropoiesis inversely correlated with hepcidin only in severe phenotypes. In moderate disease, no independent predictors of hepcidin were identifiable; nevertheless, the low hepcidin levels indicate a significant risk for iron overload. In a population survey of Sri Lankan schoolchildren, β-thalassemia (but not HbE) trait was associated with increased erythropoiesis and mildly suppressed hepcidin, suggesting an enhanced propensity to accumulate iron. In summary, the influence of erythropoiesis on hepcidin suppression associates with phenotypic disease variation and pathogenesis in HbE β-thalassemia and indicates that the epidemiology of β-thalassemia trait requires consideration when planning public health iron interventions.
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47
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Gonzales GF, Chaupis D. Higher androgen bioactivity is associated with excessive erythrocytosis and chronic mountain sickness in Andean Highlanders: a review. Andrologia 2014; 47:729-43. [PMID: 25277225 DOI: 10.1111/and.12359] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/12/2014] [Indexed: 01/12/2023] Open
Abstract
Populations living at high altitudes (HA), particularly in the Peruvian Central Andes, are characterised by presenting subjects with erythrocytosis and others with excessive erythrocytosis (EE)(Hb>21 g dl(-1) ). EE is associated with chronic mountain sickness (CMS), or lack of adaptation to HA. Testosterone is an erythropoietic hormone and it may play a role on EE at HA. The objective of the present review was to summarise findings on role of serum T levels on adaptation at HA and genes acting on this process. Men at HA without EE have higher androstenedione levels and low ratio androstenedione/testosterone than men with EE, suggesting low activity of 17beta-hydroxysteroid dehydrogenase (17beta-HSD), and this could be a mechanism of adaptation to HA. Higher conversion of dehydroepiandrosterone to testosterone in men with EE suggests nigher 17beta-HSD activity. Men with CMS at Peruvian Central Andes have two genes SENP1, and ANP32D with higher transcriptional response to hypoxia relative to those without. SUMO-specific protease 1 (SENP1) is an erythropoiesis regulator, which is essential for the stability and activity of hypoxia-inducible factor 1 (HIF-1α) under hypoxia. SENP1 reverses the hormone-augmented SUMOylation of androgen receptor (AR) increasing the transcription activity of AR.In conclusion, increased androgen activity is related with CMS.
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Affiliation(s)
- G F Gonzales
- Laboratory of Endocrinology and Reproduction, High Altitude Research Institute and Department of Biological and Physiological Sciences, Faculty of Sciences and Philosophy, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - D Chaupis
- Laboratory of Endocrinology and Reproduction, High Altitude Research Institute and Department of Biological and Physiological Sciences, Faculty of Sciences and Philosophy, Universidad Peruana Cayetano Heredia, Lima, Peru
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Ravasi G, Pelucchi S, Greni F, Mariani R, Giuliano A, Parati G, Silvestri L, Piperno A. Circulating factors are involved in hypoxia-induced hepcidin suppression. Blood Cells Mol Dis 2014; 53:204-10. [PMID: 25065484 DOI: 10.1016/j.bcmd.2014.06.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Accepted: 06/30/2014] [Indexed: 12/21/2022]
Abstract
Hepcidin transcription is strongly down-regulated under hypoxic conditions, however whether hypoxia inhibits hepcidin directly or indirectly is still unknown. We investigated the time course of hypoxia-mediated hepcidin down-regulation in vivo in healthy volunteers exposed to hypobaric hypoxia at high altitude and, based on the hypothesis that circulating factors are implicated in hepcidin inhibition, we analyzed the effect of sera of these volunteers exposed to normoxia and hypoxia on hepcidin expression in Huh-7 cell lines. Hypoxia led to a significant hepcidin down-regulation in vivo that was almost complete within 72h of exposure and followed erythropoietin induction. This delay in hepcidin down-regulation suggests the existence of soluble factor/s regulating hepcidin production. We then stimulated HuH-7 cells with normoxic and hypoxic sera to analyze the effects of sera on hepcidin regulation. Hypoxic sera had a significant inhibitory effect on hepcidin promoter activity assessed by a luciferase assay, although the amount of such decrease was not as relevant as that observed in vivo. Cellular mRNA analysis showed that a number of volunteers' sera inhibited hepcidin expression, concurrently with ID1 inhibition, suggesting that inhibitory factor(s) may act through the SMAD-pathway.
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Affiliation(s)
- Giulia Ravasi
- Department of Health Science, University Milano-Bicocca, Monza, Italy
| | - Sara Pelucchi
- Department of Health Science, University Milano-Bicocca, Monza, Italy
| | - Federico Greni
- Department of Health Science, University Milano-Bicocca, Monza, Italy
| | | | - Andrea Giuliano
- Department of Health Science, University Milano-Bicocca, Monza, Italy; Department of Cardiology, Italian Institute for Auxology, Milan, Italy
| | - Gianfranco Parati
- Department of Health Science, University Milano-Bicocca, Monza, Italy; San Gerardo Hospital, Monza, Italy; Department of Cardiology, Italian Institute for Auxology, Milan, Italy
| | - Laura Silvestri
- Division of Genetics and Cell Biology, San Raffaele Scientific Institute and Vita Salute University, Milan, Italy
| | - Alberto Piperno
- Department of Health Science, University Milano-Bicocca, Monza, Italy; San Gerardo Hospital, Monza, Italy; Consortium of Human Molecular Genetics, Monza, Italy.
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Govus AD, Abbiss CR, Garvican-Lewis LA, Swinkels DW, Laarakkers CM, Gore CJ, Peeling P. Acute hypoxic exercise does not alter post-exercise iron metabolism in moderately trained endurance athletes. Eur J Appl Physiol 2014; 114:2183-91. [DOI: 10.1007/s00421-014-2938-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2014] [Accepted: 06/12/2014] [Indexed: 12/11/2022]
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Abstract
Although most circulating iron in blood plasma is destined for erythropoiesis, the mechanisms by which erythropoietic demand modulates the iron supply ("erythroid regulators") remain largely unknown. Iron absorption, plasma iron concentrations, and tissue iron distribution are tightly controlled by the liver-produced hormone hepcidin. During the last decade, much progress has been made in elucidating hepcidin regulation by iron and inflammation. This review discusses the less understood mechanisms and mediators of hepcidin suppression in physiologically and pathologically stimulated erythropoiesis.
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