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Query: UMLS:C0002871 (anemia)
 52,094 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Hepcidin is the principal iron regulatory hormone, controlling the systemic absorption and remobilization of iron from intracellular stores. Recent in vivo studies have shown that hepcidin is down-regulated by erythropoiesis, anemia, and hypoxia, which meets the need of iron input for erythrocyte production. Erythropoietin (EPO) is the primary signal that triggers erythropoiesis in anemic and hypoxic conditions. Therefore, a direct involvement of EPO in hepcidin regulation can be hypothesized. We report here the regulation of hepcidin expression by EPO, in a dose-dependent manner, in freshly isolated mouse hepatocytes and in the HepG2 human hepatocyte cell model. The effect is mediated through EPOR signaling, since hepcidin mRNA levels are restored by pretreatment with an EPOR-blocking antibody. The transcription factor C/EBPalpha showed a pattern of expression similar to hepcidin, at the mRNA and protein levels, following EPO and anti-EPOR treatments. Chromatin immunoprecipitation experiments showed a significant decrease of C/EBPalpha binding to the hepcidin promoter after EPO supplementation, suggesting the involvement of this transcription factor in the transcriptional response of hepcidin to EPO.
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PMID:Erythropoietin mediates hepcidin expression in hepatocytes through EPOR signaling and regulation of C/EBPalpha. 1832 22

Iron is utilised by the body for oxygen transport and energy production, and is therefore essential to athletic performance. Commonly, athletes are diagnosed as iron deficient, however, contrasting evidence exists as to the severity of deficiency and the effect on performance. Iron losses can result from a host of mechanisms during exercise such as hemolysis, hematuria, sweating and gastrointestinal bleeding. Additionally, recent research investigating the anemia of inflammation during states of chronic disease has allowed us to draw some comparisons between unhealthy populations and athletes. The acute-phase response is a well-recognised reaction to both exercise and disease. Elevated cytokine levels from such a response have been shown to increase the liver production of the hormone Hepcidin. Hepcidin up-regulation has a negative impact on the iron transport and absorption channels within the body, and may explain a potential new mechanism behind iron deficiency in athletes. This review will attempt to explore the current literature that exits in this new area of iron metabolism and exercise.
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PMID:Athletic induced iron deficiency: new insights into the role of inflammation, cytokines and hormones. 1836 40

The precise regulation of the iron-regulatory hormone hepcidin is essential to maintain body iron homeostasis: Hepcidin deficiency induces iron overload, and hepcidin excess results in anaemia. Mutations in the gene HFE2 cause severe iron overload and are associated with low hepcidin expression. Recent data suggest that HFE2 is a bone morphogenetic protein (BMP) co-receptor, and that the decreased hepcidin mRNA expression because of HFE2 dysfunction is a result of impaired BMP signalling ability. In this study, we identify a critical BMP-responsive element (BMP-RE) at position -84/-79 of the hepcidin promoter. We show that this element mediates HFE2-dependent basal hepcidin mRNA expression under control conditions. Unexpectedly, the mutation of the same BMP-RE element also severely impairs hepcidin activation in response to IL-6. These data uncover a missing link in the HFE2-mediated control of hepcidin expression and suggest that the BMP-RE controls hepcidin promoter activity mediated by HFE2 and inflammatory stimuli.
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PMID:A bone morphogenetic protein (BMP)-responsive element in the hepcidin promoter controls HFE2-mediated hepatic hepcidin expression and its response to IL-6 in cultured cells. 1842 30

Hepcidin is a small protein comprised of 25 amino acids, synthesized in the liver. It was first described in 2001 as a component of the innate immunity due to its antimicrobial activity. Soon after, hepcidin was recognized as a key component in iron homeostasis, involved in maladies of iron overload or iron deficiency. Hepcidin acts by binding to the transmembrane protein ferroportin, in charge of exporting iron from cells. Upon binding to ferroportin, the latter is internalized into cytoplasmic lysosomes and is hydrolyzed, thus iron is accumulating in cells, and hypoferremia ensues. In hereditary and juvenile types of hemochromatosis, iron overload could be partially due to the down-regulation of hepcidin by the mutated genes HFE and HJV. In ferroportin disease, hepcidin synthesis is not inhibited, yet cells are still overloaded with iron due to mutations in ferroportin, preventing the binding of hepcidin and iron export from cell to the blood. Hepcidin has also been implicated in the scenario related to as "anemia of inflammation". In this condition significant hypoferremia develops as a result of acute sepsis, but also in wake of infections, chronic inflammation, rheumatic diseases and in certain malignancies. Such scarcity of iron leads to anemia that may not be corrected by erythropoietin treatment, and hepcidin synthesis in such anemic state is dramatically elevated. Future therapeutic approach may attempt administering synthetic hepcidin, or its antagonists, to correct states of iron overload or scarcity.
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PMID:[Hepcidin--the discovery of a small protein with a pivotal role in iron homeostasis]. 1848 71

Anemia of inflammation in patients with acute or chronic acute-phase activation is a common clinical problem. Hepcidin is a peptide shown to be the principal regulator of the absorption and systemic distribution of iron. Main inducers of hepcidin are iron overload, hypoxia and inflammation, where the latter has been linked to hepcidin via increased interleukin-6 (IL-6). This article addresses the impact and time course of postoperative acute-phase reaction in humans following heart surgery on prohepcidin, hepcidin, hematological markers and IL-6 concentrations. Serum concentrations of prohepcidin, hepcidin, IL-6 and hematological iron parameters were studied in five male patients without infection before and after heart surgery. This study, which is the first to report the impact on serum hepcidin and serum prohepcidin concentrations in patients following surgery, clearly demonstrates the induction of hypoferremia due to the postoperative acute-phase reaction. Significant changes were seen for serum iron concentration, transferrin saturation, total iron binding capacity and hemoglobin concentration. A significant increase in ferritin concentration was seen 96-144 h postoperatively. Additionally, there were significant alterations in both serum hepcidin after 96-144 h and serum prohepcidin after 48 h compared with preoperative values. Serum prohepcidin decreased, whereas serum hepcidin increased. In conclusion, changes in serum prohepcidin were followed by an increase in serum hepcidin. This speaks in favor of a chain of action where proteolytic trimming of serum prohepcidin results in increased serum hepcidin. However, hypoferremia appeared prior to the changes in serum prohepcidin and serum hepcidin.
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PMID:Hepcidin, interleukin-6 and hematological iron markers in males before and after heart surgery. 1849 62

Hepcidin has recently been recognized as a hormone essential to the negative regulation of iron. Synthesis of hepcidin is increased by iron overload or inflammation, and decreased by iron deficiency, anemia and erythropoietin. Dialysis patients frequently suffer the effects of both hepcidin increasing and decreasing factors. In this study, we investigated, for the first time, pro-hepcidin in dialysis patients while minimizing or manipulating these factors. We measured the serum pro-hepcidin in 23 hemodialysis patients without inflammation (the HD group) and 10 age-matched healthy volunteers. Those patients in the HD group were assigned to an iron-deficiency group (the ID group) or a non-iron deficiency subgroup (non-ID group). The HD group was followed up for two months. Iron therapy was performed in the ID group during the follow-up period. At the end of this time we evaluated the influence of iron therapy. Pro-hepcidin was similar in the HD groups and the healthy controls (295.1 [241.9, 413.7] vs. 301.7 [280.5, 383.5] ng/mL; not significant) despite the presence of hepcidin-decreasing factors. Pro-hepcidin in the ID group was significantly lower than in the non-ID group (262.6 [233.1, 295.1] vs. 359.2 [282.3, 446.5] ng/mL; P < 0.05). In patients newly acquiring ID during follow-up without iron supplementation, pro-hepcidin fell significantly (from 444.7 [389.4, 470.1] to 299.8 [233.4, 330.4] ng/mL; P < 0.05). Pro-hepcidin also showed an increase after ID was treated with iron administration (from 246.9 [205.5, 329.1] to 344.6 [290.1, 377.9] ng/mL; not significant). Pro-hepcidin could serve as a marker for functional iron deficiency and disordered iron utilization in HD. Underlying mechanisms and improvements in measurement techniques will require additional investigation.
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PMID:Serum pro-hepcidin as an indicator of iron status in dialysis patients. 1893 30

Familial amyloidosis TTR V30M (FAP-I) usually presents as a sensorimotor and autonomic neuropathy. Anemia was first described in this disease more than 20 years ago and classified as an anemia of chronic disease. However, so far no studies have addressed the role of inflammatory proteins in this disease. The anemia affects 24.8% of symptomatic FAP-I Portuguese patients, and is associated with low serum erythropoietin levels, independently of the presence of clinical nephropathy. In this study we evaluate the role of systemic inflammation on the erythropoietin production and anemia genesis in FAP-I. Data from 24 FAP-I patients (50% with anemia) and 33 healthy controls were analysed. Laboratory data included hemoglobin, hematocrit, ferritin, transferrin saturation, soluble transferrin receptors (sTR), prohepcidin, hepcidin-25, C-reactive protein (CRP), interleukin-6 and erythropoietin levels. In general, FAP-I patients presented significantly lower hemoglobin, hematocrit and observed/expected erythropoietin levels. Mean sTR was lower in FAP-I patients than in controls (2.36+/-1.3 vs 2.96+/-0.8 mg/l, P=0.055) correlating with hemoglobin and hematocrit. As expected, sTR were positively correlated with erythropoietin both in controls and in FAP-I patients. No significant differences on CRP, interleukin-6, transferrin saturation, ferritin and hepcidin-25 were found between anemic and non-anemic FAP-I patients and between non-anemic FAP-I patients and healthy controls. In all groups, a positive correlation was observed between hepcidin-25 and ferritin. Surprisingly, significantly lower prohepcidin levels were found in FAP-I patients, with or without anemia, not correlated with serum hepcidin-25 levels. In general, the decreased observed/expected EPO levels in FAP-I correlated with the prohepcidin levels, therefore raising the possibility that a common defect in these two hormones may be somehow involved in the genesis of the disease.
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PMID:Low serum levels of prohepcidin, but not hepcidin-25, are related to anemia in familial amyloidosis TTR V30M. 1854 72

Hepcidin is a key regulator of iron metabolism and a mediator of anemia in inflammation. Recent in vitro studies recognized prohepcidin as a type II acute phase protein regulating via interleukin-6. The aim of the present study was to investigate the time course of plasma prohepcidin after a large cardiac surgery in relation to IL-6 and other inflammatory parameters. Patients with chronic thromboembolic hypertension (n=22, males/females 14/8, age 51.9+/-10.2 years) underwent pulmonary endarterectomy using cardiopulmonary bypass and deep hypothermic circulatory arrest were included into study. Arterial concentrations of prohepcidin, IL-1beta, IL-6, IL-8, tumor necrosis factor-alpha, and C-reactive protein were measured before/after sternotomy, after circulatory arrest, after separation from bypass, and then 12, 18, 24, 36, 48 h and 72 h after the separation from bypass. Hemodynamic parameters, hematocrit and markers of iron metabolism were followed up. Pulmonary endarterectomy induced a 48% fall in plasma prohepcidin; minimal concentrations were detected after separation from cardiopulmonary bypass. Prohepcidin decline correlated with an extracorporeal circulation time (p<0.01), while elevated IL-6 levels were inversely associated with duration of prohepcidin decline. Postoperative prohepcidin did not correlate with markers of iron metabolism or hemoglobin concentrations within a 72-h period after separation from CPB. Prohepcidin showed itself as a negative acute phase reactant during systemic inflammatory response syndrome associated with a cardiac surgery. Results indicate that the evolution of prohepcidin in postoperative period implies the antagonism of stimulatory effect of IL-6 and contraregulatory factors inhibiting prohepcidin synthesis or increasing prohepcidin clearance.
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PMID:Plasma prohepcidin as a negative acute phase reactant after large cardiac surgery with a deep hypothermic circulatory arrest. 1909 40

Iron deficiency relatively observed in pregnant women is assumed to be enhanced by cigarette smoking. Hepcidin, a peptide hormone produced by the liver as pro-hepcidin, has recently emerged as a central mediator of iron metabolism. Hepcidin regulates intestinal iron absorption, macrophage iron release, and the placental passage of iron. Maternal smoking is associated with increased fetal iron requirements and stimulates fetal erythropoiesis. This is probably through a hypoxic effect on the fetus, and is dose related to the maternal smoking level. It is known that anemia and hypoxia suppress hepcidine mRNA expression. Therefore the aim of the study was to estimate the effect of tobacco smoking on serum pro-hepcidin levels and some iron parameters in pregnant women and umbilical cord blood. We also studied correlation between pro-hepcidin and others iron markers in mothers and their newborns. Healthy, pregnant women (n = 50), patients of Clinical Department of Obstetrics and Gynecology, Institute of Mother and Child were divided into groups nonsmoking and smoking according to questionnaire declaration. Serum concentrations of pro-hepcidin were determined by immunoenzymathic method using a commercial pro-hepcidin assay (DRG, Germany). Levels of ferritin and transferrin were measured by immunoturbidimetric method and iron by photometric test with ferrozine using HORIBA ABX kits (France) and Cobas Mira analyser (Roche, Switzerland). Levels of hemoglobin and hematocrite were determined using commercially available kits on Pentra 60 analyser (ABX, France). We observed that the mean concentration of pro-hepcidin in serum of smoking pregnant women was statistically lower than in tobacco abstinent (101.9 +/- 28.6 ng/ml vs 88.3 +/- 18.2 ng/ml; p < 0.01). Levels of others studied iron markers were similar in both group except total iron concentration, which was 20% lower in smoking mothers than in nonsmoking ones. In umbilical cord blood of infants born to smoking women level of pro-hepcidin was significantly lower than in tobacco abstinent (54.2 +/- 14.0 ng/ml vs 76.8 +/- 21.4 ng/ml, p < 0.0001). We observed positive correlation between concentrations of that prohormone in serum of mothers and cord blood of their newborns in nonsmoking group (r = 0.54; p < 0.02) as well as in smoking ones (r = 0.68; p < 0.05). In addition, concentrations of ferritin, transferin and total iron were lower by 30%, 13% and 20% respectively in cord blood of smoking than nonsmoking group. The differences were statistically significant (p < 0.05). Our analysis revealed no correlation between serum pro-hepcidin levels and other studied parameters of iron status both in the mothers and children groups. Our results indicate that tobacco smoking during pregnancy affected pro-hepcidine levels in serum of mothers and their newborns. Low concentrations of some iron markers in umbilical cord blood suggest that mother's smoking could lead to subclinical iron deficiency in fetus. No anemia were observed in both studied groups of mothers that could explain no relationships between pro-hepcidin and others parameters of iron status.
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PMID:[The effect of tobacco smoking during pregnancy on concentration of pro-hepcidin and some parameters of iron metabolism in matched-maternal cord pairs]. 1918 26

Hepcidin is a critical inhibitor of iron export from macrophages, enterocytes, and hepatocytes. Given that it is filtered and degraded by the kidney, its elevated levels in renal failure have been suggested to play a role in the disordered iron metabolism of uremia, including erythropoietin resistance. Here, we used a novel radioimmunoassay for hepcidin-25, the active form of the hormone, to measure its levels in renal disease. There was a significant diurnal variation of hepcidin and a strong correlation to ferritin levels in normal volunteers. In 44 patients with mild to moderate kidney disease, hepcidin levels were significantly elevated, positively correlated with ferritin but inversely correlated with the estimated glomerular filtration rate. In 94 stable hemodialysis patients, hepcidin levels were also significantly elevated, but this did not correlate with interleukin-6 levels, suggesting that increased hepcidin was not due to a general inflammatory state. Elevated hepcidin was associated with anemia, but, intriguingly, the erythropoietin dose was negatively correlated with hepcidin, suggesting that erythropoietin suppresses hepcidin levels. This was confirmed in 7 patients when hepcidin levels significantly decreased after initiation of erythropoietin treatment. Our results show that hepcidin is elevated in renal disease and suggest that higher hepcidin levels do not predict increased erythropoietin requirements.
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PMID:Plasma hepcidin levels are elevated but responsive to erythropoietin therapy in renal disease. 1987 58


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