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1.  A seven day running training period increases basal urinary hepcidin levels as compared to cycling 
Background
This investigation compared the effects of an extended period of weight-bearing (running) vs. non-weight-bearing (cycling) exercise on hepcidin production and its implications for iron status.
Methods
Ten active males performed two separate exercise training blocks with either running (RTB) or cycling (CTB) as the exercise mode. Each block consisted of five training sessions (Day 1, 2, 4, 5, 6) performed over a seven day period that were matched for exercise intensity. Basal venous blood samples were obtained on Day 1 (D1), and on Recovery Days 3 (R3) and 7 (R7) to assess iron status, while basal and 3 h post-exercise urinary hepcidin levels were measured on D1, D2, D6, as well as R3 and R7 (basal levels only) for each condition.
Results
Basal urinary hepcidin levels were significantly elevated (p ≤ 0.05) at D2, R3 and R7 as compared to D1 in RTB. Furthermore, 3 h post-exercise urinary hepcidin levels on D1 were also significantly higher in RTB compared to CTB (p ≤ 0.05). In CTB, urinary hepcidin levels were not statistically different on D1 as compared to R7. Iron parameters were not significantly different at D1 compared to R3 and R7 during both conditions.
Conclusions
These results suggest that basal hepcidin levels may increase over the course of an extended training program, especially if a weight-bearing exercise modality is undertaken. However, despite any variations in hepcidin production, serum iron parameters in both RTB and CTB were unaffected, possibly due to the short duration of each training block. In comparing running to cycling, non-weight-bearing activity may require more training sessions, or sessions of extended duration, before any significant changes in basal hepcidin levels appear. Chronic elevations in hepcidin levels may help to explain the high incidence of iron deficiency in athletes.
doi:10.1186/1550-2783-11-14
PMCID: PMC3991905  PMID: 24716892
Iron deficiency; Weight-bearing exercise; Non-weight-bearing exercise; Cytokines
2.  Low Hepcidin Levels in Severely Anemic Malawian Children with High Incidence of Infectious Diseases and Bone Marrow Iron Deficiency 
PLoS ONE  2013;8(12):e78964.
Introduction
A reliable diagnostic biomarker of iron status is required for severely anemic children living in malarious areas because presumptive treatment with iron may increase their infection risk if they are not iron deficient. Current biomarkers are limited because they are altered by host inflammation. In this study hepcidin concentrations were assessed in severely anemic children living in a highly malarious area of Malawi and evaluated against bone marrow iron in order to determine the usefulness of hepcidin as a point of care test.
Methods
207 severely anemic children were assessed for levels of hepcidin, ferritin, serum transferrin receptor, erythropoietin, hematological indices, C-reactive protein, interleukin-6, malaria parasites and HIV infection. Deficiency of bone marrow iron stores was graded and erythroblast iron incorporation estimated. Interaction of covariates was assessed by structural-equation-modeling.
Results and Conclusion
Hepcidin was a poor predictor of bone marrow iron deficiency (sensitivity 66.7%; specificity 48.5%), and of iron incorporation (sensitivity 54.2%; specificity 61.8%), and therefore would have limitations as a point of care test in this category of children. As upregulation of hepcidin by inflammation and iron status was blunted by erythropoietin in this population, enhanced iron absorption through the low hepcidin values may increase infection risk. Current recommendations to treat all severely anemic children living in malarious areas with iron should therefore be reconsidered.
doi:10.1371/journal.pone.0078964
PMCID: PMC3855157  PMID: 24339866
3.  Improved Mass Spectrometry Assay For Plasma Hepcidin: Detection and Characterization of a Novel Hepcidin Isoform 
PLoS ONE  2013;8(10):e75518.
Mass spectrometry (MS)-based assays for the quantification of the iron regulatory hormone hepcidin are pivotal to discriminate between the bioactive 25-amino acid form that can effectively block the sole iron transporter ferroportin and other naturally occurring smaller isoforms without a known role in iron metabolism. Here we describe the design, validation and use of a novel stable hepcidin-25+40 isotope as internal standard for quantification. Importantly, the relative large mass shift of 40 Da makes this isotope also suitable for easy-to-use medium resolution linear time-of-flight (TOF) platforms. As expected, implementation of hepcidin-25+40 as internal standard in our weak cation exchange (WCX) TOF MS method yielded very low inter/intra run coefficients of variation. Surprisingly, however, in samples from kidney disease patients, we detected a novel peak (m/z 2673.9) with low intensity that could be identified as hepcidin-24 and had previously remained unnoticed due to peak interference with the formerly used internal standard. Using a cell-based bioassay it was shown that synthetic hepcidin-24 was, like the -22 and -20 isoforms, a significantly less potent inducer of ferroportin degradation than hepcidin-25. During prolonged storage of plasma at room temperature, we observed that a decrease in plasma hepcidin-25 was paralleled by an increase in the levels of the hepcidin-24, -22 and -20 isoforms. This provides first evidence that all determinants for the conversion of hepcidin-25 to smaller inactive isoforms are present in the circulation, which may contribute to the functional suppression of hepcidin-25, that is significantly elevated in patients with renal impairment. The present update of our hepcidin TOF MS assay together with improved insights in the source and preparation of the internal standard, and sample stability will further improve our understanding of circulating hepcidin and pave the way towards further optimization and standardization of plasma hepcidin assays.
doi:10.1371/journal.pone.0075518
PMCID: PMC3790851  PMID: 24124495
4.  Hepcidin-25 in Chronic Hemodialysis Patients Is Related to Residual Kidney Function and Not to Treatment with Erythropoiesis Stimulating Agents 
PLoS ONE  2012;7(7):e39783.
Hepcidin-25, the bioactive form of hepcidin, is a key regulator of iron homeostasis as it induces internalization and degradation of ferroportin, a cellular iron exporter on enterocytes, macrophages and hepatocytes. Hepcidin levels are increased in chronic hemodialysis (HD) patients, but as of yet, limited information on factors associated with hepcidin-25 in these patients is available. In the current cross-sectional study, potential patient-, laboratory- and treatment-related determinants of serum hepcidin-20 and -25, were assessed in a large cohort of stable, prevalent HD patients. Baseline data from 405 patients (62% male; age 63.7±13.9 [mean SD]) enrolled in the CONvective TRAnsport STudy (CONTRAST; NCT00205556) were studied. Predialysis hepcidin concentrations were measured centrally with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Patient-, laboratory- and treatment related characteristics were entered in a backward multivariable linear regression model. Hepcidin-25 levels were independently and positively associated with ferritin (p<0.001), hsCRP (p<0.001) and the presence of diabetes (p = 0.02) and inversely with the estimated glomerular filtration rate (p = 0.01), absolute reticulocyte count (p = 0.02) and soluble transferrin receptor (p<0.001). Men had lower hepcidin-25 levels as compared to women (p = 0.03). Hepcidin-25 was not associated with the maintenance dose of erythropoiesis stimulating agents (ESA) or iron therapy. In conclusion, in the currently studied cohort of chronic HD patients, hepcidin-25 was a marker for iron stores and erythropoiesis and was associated with inflammation. Furthermore, hepcidin-25 levels were influenced by residual kidney function. Hepcidin-25 did not reflect ESA or iron dose in chronic stable HD patients on maintenance therapy. These results suggest that hepcidin is involved in the pathophysiological pathway of renal anemia and iron availability in these patients, but challenges its function as a clinical parameter for ESA resistance.
doi:10.1371/journal.pone.0039783
PMCID: PMC3396629  PMID: 22808058
5.  Iron Homeostasis in Mother and Child during Placental Malaria Infection 
In malaria-endemic areas, iron deficiency and placental Plasmodium falciparum infection commonly coexist. In primigravidae and their newborns, hepcidin and other iron parameters were evaluated in groups and classified according to placental P. falciparum and maternal anemia status. Mothers had relatively high hepcidin levels considering their low iron status. In cord blood, levels of hepcidin, hemoglobin, and other iron parameters were also similar for groups. We conclude that maternal hepcidin is not significantly altered as a function of placental infection and/or anemia. Importantly, fetal hemoglobin and iron status were also unaffected, regardless of the presence of placental infection or maternal anemia.
doi:10.4269/ajtmh.2011.10-0250
PMCID: PMC3005511  PMID: 21212218
6.  Hepcidin in anemia of chronic heart failure 
American journal of hematology  2011;86(1):107-109.
Anemia is a common finding among patients with chronic heart failure. Although co-morbidities, such as kidney failure, might contribute to the pathogenesis of anemia, many patients with heart failure do not have any other obvious etiology for their anemia. We investigated whether anemia in heart failure is associated with an elevation in hepcidin concentration.
We used time-of-flight mass spectrometry to measure hepcidin concentration in urine and serum samples of patients with heart failure and in control subjects. We found that the concentration of hepcidin was lower in urine samples of patients with heart failure compared to those of control subjects. Serum hepcidin was also reduced in heart failure but was not significantly lower than that in controls. There were no significant differences between hepcidin levels in patients with heart failure and anemia compared to patients with heart failure and normal hemoglobin. We concluded that hepcidin probably does not play a major role in pathogenesis of anemia in patients with chronic heart failure.
doi:10.1002/ajh.21902
PMCID: PMC3076004  PMID: 21080339
Anemias; Cytokines; Iron

Results 1-6 (6)