Serum hepcidin is significantly associated with iron absorption from food and supplemental sources in healthy young women

Effects of iron supplements and iron-containing micronutrient powders on the gut microbiome in Bangladeshi infants: a randomized controlled trial

Anemia is highly prevalent globally, especially in young children in low-income countries, where it often overlaps with a high burden of diarrheal disease. Distribution of iron interventions (as supplements or iron-containing multiple micronutrient powders, MNPs) is a key anemia reduction strategy. Small studies in Africa indicate iron may reprofile the gut microbiome towards pathogenic species. We seek to evaluate the safety of iron and MNPs based on their effects on diversity, composition, and function of the gut microbiome in children in rural Bangladesh as part of a large placebo-controlled randomized controlled trial of iron or MNPs given for 3 months (ACTRN12617000660381). In 923 infants, we evaluate the microbiome before, immediately following, and nine months after interventions, using 16S rRNA gene sequencing and shotgun metagenomics in a subset. We identify no increase in diarrhea with either treatment. In our primary analysis, neither iron nor MNPs alter gut microbiome diversity or composition. However, when not adjusting for multiple comparisons, compared to placebo, children receiving iron and MNPs exhibit reductions in commensal species (e.g., Bifidobacterium, Lactobacillus) and increases in potential pathogens, including Clostridium. These increases are most evident in children with baseline iron repletion and are further supported by trend-based statistical analyses.

Effects of Dietary Supplementation in Patients with Restless Legs Syndrome: A Systematic Review

Restless legs syndrome (RLS) is a common neurological disorder. It disrupts sleep and well-being and is often associated with other conditions. This review examines the potential of dietary supplements to manage RLS symptoms and reduce reliance on medications. A total of 10 randomized clinical trials involving 482 participants were analyzed, focusing on the impact of various supplements on symptom severity, sleep quality, and daytime sleepiness. Findings suggest some supplements may have positive results. Magnesium oxide and vitamin B6 significantly improved sleep quality and RLS symptoms, with magnesium showing greater effectiveness. Vitamin D supplementation did not show significant benefits. Oral iron has promising results, indicating potential efficacy but issues related to compliance and absorption. Both vitamins C and E positively affect RLS symptoms, likely due to their antioxidant properties. Valerian improved RLS and sleep but did not show a statistically significant improvement. Despite these encouraging results, a high risk of bias was noted in half of the studies, emphasizing the need for more rigorous research. Overall, this review suggests that dietary supplements may be a promising approach to managing RLS. However, further investigation is required to confirm the efficacy and safety.

The magnitude of the plasma hepcidin response to oral iron supplements depends on the iron dosage

BACKGROUND

Iron deficiency without anaemia is a common health problem, especially in young menstruating women. The efficacy of the usually recommended oral iron supplementation is limited due to increased plasma hepcidin concentration, which reduces iron absorption and leads to side effects such as intestinal irritation. This observation raises the question of how low-dose iron therapy may affect plasma hepcidin levels and whether oral iron intake dose-dependently affects plasma hepcidin production.

METHODS

Fifteen non-anaemic women with iron deficiency (serum ferritin ≤30 ng/ml) received a single dose of 0, 6, 30, or 60 mg of elemental oral iron as ferrous sulfate on different days. Plasma hepcidin was measured before and seven hours after each dose.

RESULTS

Subjects had an average age of 23 (standard deviation = 3.0) years and serum ferritin of 24 ng/ml (interquartile range = 16-27). The highest mean change in plasma hepcidin levels was measured after ingesting 60 mg of iron, increasing from 2.1 ng/ml (interquartile range = 1.6-2.9) to 4.1 ng/ml (interquartile range = 2.5-6.9; p < 0.001). Iron had a significant dose-dependent effect on the absolute change in plasma hepcidin (p = 0.008), where lower iron dose supplementation resulted in lower plasma hepcidin levels. Serum ferritin levels were significantly correlated with fasting plasma hepcidin levels (R2 = 0.504, p = 0.003) and the change in plasma hepcidin concentration after iron intake (R2 = 0.529, p = 0.002).

CONCLUSION

We found a dose-dependent effect of iron supplementation on plasma hepcidin levels. Lower iron dosage results in a smaller increase in hepcidin and might thus lead to more efficient intestinal iron absorption and fewer side effects. The effectiveness and side effects of low-dose iron treatment in women with iron deficiency should be further investigated. This study was registered at the Swiss National Clinical Trials Portal (2021-00312) and ClinicalTrials.gov (NCT04735848).

Circulating microRNAs and hepcidin as predictors of iron homeostasis and anemia among school children: a biochemical and cross-sectional survey analysis

BACKGROUND

MicroRNAs (miRNAs) can control several biological processes. Thus, the existence of these molecules plays a significant role in regulating human iron metabolism or homeostasis.

PURPOSE

The study aimed to determine the role of circulating microRNAs and hepcidin in controlling iron homeostasis and evaluating possible anemia among school children.

METHODS

The study was based on a biochemical and cross-sectional survey study that included three hundred fifty school children aged 12-18 years old. RT-PCR and immunoassay analysis were accomplished to estimate iron concentration, Hgb, serum ferritin (SF), soluble transferrin receptor (sTfR), total body iron stores (TIBs), total oxidative stress (TOS), total antioxidant capacity (TAC), α-1-acid glycoprotein (AGP), high sensitive C-reactive protein (hs-CRP), and miRNAs; miR-146a, miR-129b, and miR-122 in 350 school adolescents.

RESULTS

Iron disorders were cross-sectionally predicted in 28.54% of the study population; they were classified into 14.26% with ID, 5.7% with IDA, and 8.6% with iron overload. The overall proportion of iron depletion was significantly higher in girls (20.0%) than in boys (8.6%). MicroRNAs; miR-146a, miR-125b, and miR-122 were significantly upregulated with lower hepcidin expression in adolescence with ID and IDA compared to iron-overloaded subjects, whereas downregulation of these miRNAs was linked with higher hepcidin. Also, a significant correlation was recorded between miRNAs, hepcidin levels, AGP, hs-CRP, TAC, and other iron-related indicators.

CONCLUSION

Molecular microRNAs such as miR-146a, miR-125b, and miR-122 were shown to provide an additional means of controlling or regulating cellular iron uptake or metabolism either via the oxidative stress pathway or regulation of hepcidin expression via activating genes encoding Hfe and Hjv activators, which promote iron regulation. Thus, circulating miRNAs as molecular markers and serum hepcidin could provide an additional means of controlling or regulating cellular iron and be associated as valuable markers in diagnosing and treating cases with different iron deficiencies.

An Overlooked Hepcidin-Cadmium Connection

Hepcidin (DTHFPICIFCCGCCHRSKCGMCCKT), an iron-regulatory hormone, is a 25-amino-acid peptide with four intramolecular disulfide bonds circulating in blood. Its hormonal activity is indirect and consists of marking ferroportin-1 (an iron exporter) for degradation. Hepcidin biosynthesis involves the N-terminally extended precursors prepro-hepcidin and pro-hepcidin, processed by peptidases to the final 25-peptide form. A sequence-specific formation of disulfide bonds and export of the oxidized peptide to the bloodstream follows. In this study we considered the fact that prior to export, reduced hepcidin may function as an octathiol ligand bearing some resemblance to the N-terminal part of the α-domain of metallothioneins. Consequently, we studied its ability to bind Zn(II) and Cd(II) ions using the original peptide and a model for prohepcidin extended N-terminally with a stretch of five arginine residues (5R-hepcidin). We found that both form equivalent mononuclear complexes with two Zn(II) or Cd(II) ions saturating all eight Cys residues. The average affinity at pH 7.4, determined from pH-metric spectroscopic titrations, is 10^10.1 M^-1 for Zn(II) ions; Cd(II) ions bind with affinities of 10^15.2 M^-1 and 10^14.1 M^-1. Using mass spectrometry and 5R-hepcidin we demonstrated that hepcidin can compete for Cd(II) ions with metallothionein-2, a cellular cadmium target. This study enabled us to conclude that hepcidin binds Zn(II) and Cd(II) sufficiently strongly to participate in zinc physiology and cadmium toxicity under intracellular conditions.

Associations Between Iron Homeostasis and Pancreatic Enzymes After an Attack of Pancreatitis

OBJECTIVES

Dysregulation of iron homeostasis and exocrine pancreatic dysfunction are linked but remain undefined in individuals with a history of pancreatitis. The objective is to investigate the relationship between iron homeostasis and pancreatic enzymes in individuals after a pancreatitis attack.

METHODS

This was a cross-sectional study of adults with a history of pancreatitis. Markers of iron metabolism (hepcidin and ferritin) and pancreatic enzymes (pancreatic amylase, pancreatic lipase, and chymotrypsin) were measured in venous blood. Habitual dietary iron intake data (total, heme, and nonheme iron) were collected. Multivariable linear regression analyses were performed while considering covariates.

RESULTS

One hundred and one participants were studied at a median of 18 months after their last pancreatitis attack. Hepcidin was significantly associated with pancreatic amylase (β coefficient, -6.68; 95% confidence interval, -12.88 to -0.48; P = 0.035) and heme iron intake (β coefficient, 0.34; 95% confidence interval, 0.08 to 0.60; P = 0.012) in the adjusted model. Hepcidin was not significantly associated with pancreatic lipase or chymotrypsin. Ferritin was not significantly associated with pancreatic enzymes and dietary iron intake.

CONCLUSIONS

An iron homeostasis-exocrine pancreas crosstalk exists in individuals after an attack of pancreatitis. The role of iron homeostasis in pancreatitis warrants high-quality purposely-designed studies.

Clinical interpretation of serum hepcidin-25 in inflammation and renal dysfunction

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log[hepcidin]:log[ferritin] ratio may serve as a biomarker for iron deficiency in complex cases.

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Hepcidin testing is not warranted in patients with CRP > 10 mg/l and/or eGFR < 30 ml/min/1.73 m².

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Inflammation is not a determinant of serum hepcidin-25 in the setting of renal dysfunction.

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eGFR is not a major determinant of serum hepcidin-25 concentration in patient with eGFR ≥ 30 ml/min/1.73 m².

Introduction

Hepcidin is a hormone that regulates systemic iron homeostasis. Serum hepcidin levels are under the influence of various stimuli, particularly inflammation and renal dysfunction. The measurement of hepcidin in circulation is a potentially useful clinical tool in the diagnosis, monitoring and treatment of iron metabolism disorder, although clinical interpretation of hepcidin level remains difficult. We evaluated he diagnostic potential and limitations of hepcidin-25 by investigating its relationship with iron and hematological indices, inflammation, and renal dysfunction.

Methods

This retrospective study included 220 adult patients not requiring dialysis. Variations of biologically active hepcidin-25 were examined using a mass spectrometry-based assay in various inflammatory and renal states. The log[hepcidin]:log[ferritin] ratio was calculated as an hepcidin index.

Results

In 220 adult patients not requiring dialysis, variation in hepcidin-25 level was significantly larger once CRP exceeded 10 mg/l (p < 0.001). Inflammation was not a determinant of hepcidin-25 in the setting of renal dysfunction. Hepcidin-25 median (7.37 nM) and variance were significantly higher (p < 0.001), once estimated glomerular filtration rate (eGFR) dropped below 30 ml/min/1.73 m². The log[hepcidin]:log[ferritin] index normalized hepcidin levels. Patients with iron deficiency have a notably lower index when compared to controls (-0.66 vs 0.3).

Conclusion

Severe renal dysfunction (eGFR < 30) affected hepcidin-25 expression and clearance to variable degree between individuals. Although, hepcidin-25 testing is not warranted in patients with infection, inflammatory autoimmune conditions (CRP > 10 mg/l) and/or severe renal dysfunction (eGFR < 30), the hepcidin index may serve as a potential biomarker for iron deficiency in complex cases.

Role of Serum and Urinary Hepcidin in Young Females of Reproductive Age in North India

Introduction  Iron deficiency is one of the most common nutritional disorders in the world affecting young females of the reproductive age group. Indeed, an ideal screening test should be capable of identifying iron deficiency long before developing anemia. Henceforth, the present study was aimed to determine utility of hepcidin in iron deficiency and to see its correlation with different iron indices.

Methods  This cross-sectional study was conducted in the Department of Biochemistry, SGT Medical College Hospital and Research Institute, Budhera, Gurugram, Haryana, India. It included 200 nonpregnant female students aged between 18 and 25 years. Estimation of hepcidin was by enzyme-linked immunosorbent assay. Quantitative estimation of serum iron, total iron-binding capacity (TIBC), and transferrin saturation was done via semi-autoanalyzer. Statistical analysis was done using SPSS v22.

Results  The reference range of urinary hepcidin established in this study was 110 to 969 ng/mg creatinine (mean ± standard deviation 328.3 ± 195.07 ng/mg creatinine). Serum hepcidin and urinary hepcidin had a significant correlation with iron indices. Area under the curve of urinary hepcidin was obtained with best combination of diagnostic sensitivity (82.6%) and specificity (83.1%) at a cutoff value of > 15.7 ng/mL and ≤ 199 ng/mg, respectively.

Conclusion  Since ferritin, TIBC, transferrin saturation, and hepcidin each represent different aspects of iron metabolism, incorporating hepcidin in the present diagnostics and combined evaluation of these indices may accord enhanced clinical information. Hepcidin would help to stratify the vulnerable young healthy female population in early stages of iron deficiency and guide proper interventions to reduce morbidity.

Prepregnancy Obesity Does Not Impact Placental Iron Trafficking

BACKGROUND

Iron is critical for fetal development. Neonates of obese women may be at risk for poor iron status at birth as a result of maternal inflammation-driven overexpression of hepcidin.

OBJECTIVES

The objective of this study was to determine differences in placental transfer of oral iron (57Fe) and expression of placental transferrin receptor 1 (TFR1) and ferroportin (FPN) mRNA and protein and their association with maternal and neonatal iron-related parameters, including maternal hepcidin, among women with and without prepregnancy (PP) obesity.

METHODS

57Fe ingested during the third trimester of pregnancy was recovered in venous umbilical cord blood among 20 PP obese [BMI (in kg/m2): 30.5-43.9] and 22 nonobese (BMI: 18.5-29.0) women aged 17-39 y. Placental TFR1 and FPN mRNA and protein expression were quantified via qPCR and Western blot. Maternal and neonatal markers of iron status and regulation, as well as inflammation, were measured. Descriptive and inferential statistical tests (e.g., Student t test, Pearson correlation) were used for data analysis.

RESULTS

There was no difference in cord blood enrichment of 57Fe or placental mRNA or protein expression of TFR1 or FPN among the women with and without PP obesity. Maternal hepcidin was not correlated with cord blood enrichment of 57Fe or placental FPN mRNA or protein expression. Maternal log ferritin (corrected for inflammation) was inversely correlated with log percent enrichment of 57Fe in cord blood (partial r = -0.50; P < 0.01, controlled for marital status) and protein expression of TFR1 (r = -0.43; P = 0.01).

CONCLUSIONS

Placental iron trafficking did not differ among women with and without PP obesity. Findings reinforce the importance of maternal iron stores in regulating placental iron trafficking.

A simplified diagnostic pathway for the differential diagnosis of iron deficiency anaemia and anaemia of chronic disease

INTRODUCTION

Iron deficiency anaemia (IDA) and anaemia of chronic disease (ACD) are common causes of anaemia with similar clinical and laboratory features. IDA is caused by low iron stores while ACD is due to iron-restricted erythropoiesis occurring in inflammatory states. Differential diagnosis requires analysis of multiple biochemical and haematological parameters. IDA can occur simultaneously to ACD (mixed aetiology). It is essential that true iron deficiency is identified, as these patients will require iron therapy. This preliminary study investigated whether hepcidin, the master regulator of iron homeostasis, in conjunction with reticulocyte haemoglobin equivalent (RetHe) has the potential to differentiate IDA from ACD, and to exclude IDA in patients with mixed aetiology.

METHODS

Hepcidin concentration (measured using a commercially available ELISA method), RetHe, and iron parameters along with C-reactive protein (CRP) were analysed in 77 Gastroenterology patients with anaemia in a secondary care setting.

RESULTS

Receiver operator characteristic (ROC) analysis showed that hepcidin at an optimal cut-off concentration of <6ng/ml could identify IDA with a sensitivity and specificity of 88.9% and 90.6% respectively and could distinguish ACD from IDA with both a sensitivity and specificity of 100% at a cut-off of >46ng/ml. Identifying true IDA in mixed aetiology patients could be achieved by RetHe analysis and applying an optimal cut-off of <30pg.

CONCLUSION

Hepcidin, in conjunction with RetHe, offers a new simplified diagnostic pathway for differential diagnosis of IDA and ACD, thereby reducing the diagnostic turnaround time and allowing appropriate treatment of patients with a true iron deficiency.

Ethnic Differences in Iron Status

Iron is unique among all minerals in that humans have no regulatable excretory pathway to eliminate excess iron after it is absorbed. Iron deficiency anemia occurs when absorbed iron is not sufficient to meet body iron demands, whereas iron overload and subsequent deposition of iron in key organs occur when absorbed iron exceeds body iron demands. Over time, iron accumulation in the body can increase risk of chronic diseases, including cirrhosis, diabetes, and heart failure. To date, only ∼30% of the interindividual variability in iron absorption can be captured by iron status biomarkers or iron regulatory hormones. Much of the regulation of iron absorption may be under genetic control, but these pathways have yet to be fully elucidated. Genome-wide and candidate gene association studies have identified several genetic variants that are associated with variations in iron status, but the majority of these data were generated in European populations. The purpose of this review is to summarize genetic variants that have been associated with alterations in iron status and to highlight the influence of ethnicity on the risk of iron deficiency or overload. Using extant data in the literature, linear mixed-effects models were constructed to explore ethnic differences in iron status biomarkers. This approach found that East Asians had significantly higher concentrations of iron status indicators (serum ferritin, transferrin saturation, and hemoglobin) than Europeans, African Americans, or South Asians. African Americans exhibited significantly lower hemoglobin concentrations compared with other ethnic groups. Further studies of the genetic basis for ethnic differences in iron metabolism and on how it affects disease susceptibility among different ethnic groups are needed to inform population-specific recommendations and personalized nutrition interventions for iron-related disorders.

Prevention of iron deficiency anemia in infants and toddlers

Anemia, defined as a low blood hemoglobin concentration, is a major global public health problem. Identification of anemia is crucial to public health interventions. It is estimated globally that 273 million children under 5 years of age were anemic in 2011, and about ~50% of those cases were attributable to iron deficiency (Lancet Global Health 1:e16-e25, 2013). Iron-deficiency anemia (IDA) in infants adversely impacts short-term hematological indices and long-term neuro-cognitive functions of learning and memory that result in both fatigue and low economic productivity. IDA contributes to death and disability and is an important risk factor for maternal and perinatal mortality, including the risks for stillbirths, prematurity, and low birth weight (Comparative Quantification of Health Risks: Global and Regional Burden of Disease Attributable to Selected Major Risk Factors. Ch. 3 (World Health Organization, Geneva, 2004)). Reduction in early infantile anemia and newborn mortality rates is possible with easily implemented, low- to no-cost intervention such as delayed cord clamping (DCC). DCC until 1-3 min after birth facilitates placental transfusion and iron-rich blood flow to the newborn. DCC, an effective anemia prevention strategy, requires cooperation among health providers involved in childbirth, and a participatory culture change in public health. Public intervention strategies must consider multiple factors associated with anemia listed in this review before designing intervention studies that aim to reduce anemia prevalence in infants and toddlers. IMPACT: Anemia, defined as a low blood hemoglobin concentration, is a major global public health problem and identification of anemia is crucial to public health interventions. Delayed cord clamping (DCC) until 1-3 min after birth facilitates placental transfusion and iron-rich blood flow to the newborn. Reduction in early infantile anemia and newborn mortality rates is possible with easily implemented, low- to no-cost intervention such as DCC.

Iron absorption during pregnancy is underestimated when iron utilization by the placenta and fetus is ignored

BACKGROUND

Maternal iron absorption during pregnancy can be evaluated using RBC incorporation of orally administered stable iron isotope. This approach underestimates true maternal absorption of iron as it does not account for absorbed iron that is transferred to the fetus or retained within the placenta.

OBJECTIVE

Our objective was to re-evaluate maternal iron absorption after factoring in these losses and identify factors associated with iron partitioning between the maternal, neonatal, and placental compartments.

METHODS

This study utilized data from stable iron isotope studies carried out in 68 women during the third trimester of pregnancy. Iron status indicators and stable iron isotopic enrichment were measured in maternal blood, umbilical cord blood, and placental tissue when available. Factors associated with iron isotope partitioning between the maternal, neonatal, and placental compartments were identified.

RESULTS

On average, true maternal absorption of iron increased by 10% (from 19% to 21%) after accounting for absorbed iron present in the newborn (P < 0.001), and further increased by 7%, (from 39% to 42%, P < 0.001) after accounting for iron retained within the placenta. On average, 2% of recovered tracer was present in the placenta and 6% was found in the newborn. Net transfer of iron to the neonate was higher in women with lower total body iron (standardized β = -0.48, P < 0.01) and lower maternal hepcidin (standardized β = -0.66, P < 0.01). In women carrying multiple fetuses, neonatal hepcidin explained a significant amount of observed variance in net placental transfer of absorbed iron (R = 0.95, P = 0.03).

CONCLUSIONS

Maternal RBC iron incorporation of an orally ingested tracer underestimated true maternal iron absorption. The degree of underestimation was greatest in women with low body iron. Maternal hepcidin was inversely associated with maternal RBC iron utilization, whereas neonatal hepcidin explained variance in net transfer of iron to the neonatal compartment.These trials were registered at clinicaltrials.gov as NCT01019096 and NCT01582802.

Hepcidin, Serum Iron, and Transferrin Saturation in Full-Term and Premature Infants during the First Month of Life: A State-of-the-Art Review of Existing Evidence in Humans

Neonates regulate iron at birth and in early postnatal life. We reviewed literature from PubMed and Ovid Medline containing data on umbilical cord and venous blood concentrations of hepcidin and iron, and transferrin saturation (TSAT), in human neonates from 0 to 1 mo of age. Data from 59 studies were used to create reference ranges for hepcidin, iron, and TSAT for full-term-birth (FTB) neonates over the first month of life. In FTB neonates, venous hepcidin increases 100% over the first month of life (to reach 61.1 ng/mL; 95% CI: 20.1, 102.0 ng/mL) compared with umbilical cord blood (29.7 ng/mL; 95% CI: 21.1, 38.3 ng/mL). Cord blood has a high concentration of serum iron (28.4 μmol/L; 95% CI: 26.0, 31.1 μmol/L) and levels of TSAT (51.7%; 95% CI: 46.5%, 56.9%). After a short-lived immediate postnatal hypoferremia, iron and TSAT rebounded to approximately half the levels in the cord by the end of the first month. There were insufficient data to formulate reference ranges for preterm neonates.

Oral iron supplementation in iron-deficient women: How much and how often?

Iron deficiency and iron deficiency anemia (IDA) are major public health problems worldwide, especially in young women. Oral iron supplementation can be an effective strategy to treat and prevent IDA, but guidelines vary. Some experts recommend doses of 150-200 mg elemental iron per day, with the dose split through the day. However, recent studies suggest this may not be an optimal regimen. The fraction of iron absorbed from high doses of oral iron is low, and unabsorbed iron can cause gut irritation, inflammation and dysbiosis, and these reduce compliance. In recent studies using serum hepcidin profiles and stable iron isotopes to quantify iron absorption in young women, we have shown that: (a) oral iron doses ≥60 mg in iron-deficient women, and doses ≥100 mg in women with IDA, stimulate an acute increase in hepcidin that persists 24 h after the dose, but subsides by 48 h; (b) therefore, to maximize fractional iron absorption, oral doses ≥60 mg should be given on alternate days; (c) the circadian increase in plasma hepcidin is augmented by a morning iron dose; therefore, iron doses should not be given in the afternoon or evening after a morning dose. If rate of Hb response is important, a pooled analysis of our data done for this review indicates that total iron absorption is also higher if twice the target daily iron dose is given on alternate days. In summary, these studies suggest changing from daily to alternate-day schedules and from divided to morning single doses increases iron absorption and may reduce side effects. Thus, providing morning doses of 60-120 mg iron as a ferrous salt given with ascorbic acid on alternate days may be an optimal oral dosing regimen for women with iron-deficiency and mild IDA.

Prepregnancy Obesity Is Not Associated with Iron Utilization during the Third Trimester

BACKGROUND

An adequate maternal iron supply is crucial for maternal red blood cell (RBC) expansion, placental and fetal growth, and fetal brain development. Obese women may be at risk for poor iron status in pregnancy due to proinflammatory-driven overexpression of hepcidin leading to decreased iron bioavailability.

OBJECTIVE

The objective of this study was to determine the impact of prepregnancy (PP) obesity on third-trimester maternal iron utilization.

DESIGN

Using the stable isotope 57Fe, we measured iron utilization in the third trimester in PP obese [BMI (in kg/m2): ≥30] and nonobese (BMI: 18.5-29.9) women. We also assessed iron status, hepcidin, inflammation, erythropoietin, dietary iron intake, and gestational weight gain. Descriptive and inferential statistical tests (e.g., Student t test, Pearson correlation) were used for data analysis.

RESULTS

Fifty pregnant women (21 PP obese, 29 PP nonobese) were included. Mean age was 27.6 ± 6.8 y and mean gestational age at time of 57Fe administration was 32.7 ± 0.7 wk. Anemia (hemoglobin <11 g/dL for non-black and <10.2 g/dL for black women) affected 38% of women (43% PP obese compared with 35% PP nonobese; P = 0.55). Women with PP obesity had significantly higher C-reactive protein (8.5 compared with 3.4 mg/L, P = 0.0007) and total body iron corrected for inflammation (6.0 compared with 4.3 mg/kg, P = 0.04) compared with the nonobese women. There was no difference in serum hepcidin or iron utilization between the PP BMI groups.

CONCLUSION

This is the first study to assess the impact of PP obesity on maternal iron utilization. We found no difference in iron utilization in the third trimester of pregnancy in women with and without PP obesity. Despite higher frequency of anemia, women with PP obesity had less depleted body iron stores, suggesting some degree of iron sequestration. This finding should be followed up and extended to understand effects on fetal iron bioavailability.

Hto, Tritiated Amino Acid Exposure and External Exposure Induce Differential Effects on Hematopoiesis and Iron Metabolism

The increased potential for tritium releases from either nuclear reactors or from new facilities raises questions about the appropriateness of the current ICRP and WHO recommendations for tritium exposures to human populations. To study the potential toxicity of tritium as a function of dose, including at a regulatory level, mice were chronically exposed to tritium in drinking water at one of three concentrations, 10 kBq.l⁻¹, 1 MBq.l⁻¹ or 20 MBq.l⁻¹. Tritium was administered as either HTO or as tritiated non-essential amino acids (TAA). After one month’s exposure, a dose-dependent decrease in red blood cells (RBC) and iron deprivation was seen in all TAA exposed groups, but not in the HTO exposed groups. After eight months of exposure this RBC decrease was compensated by an increase in mean globular volume - suggesting the occurrence of an iron deficit-associated anemia. The analysis of hematopoiesis, of red blood cell retention in the spleen and of iron metabolism in the liver, the kidneys and the intestine suggested that the iron deficit was due to a decrease in iron absorption from the intestine. In contrast, mice exposed to external gamma irradiation at equivalent dose rates did not show any change in red blood cell numbers, white blood cell numbers or in the plasma iron concentration. These results showed that health effects only appeared following chronic exposure to concentrations of tritium above regulatory levels and the effects seen were dependent upon the speciation of tritium.

Hepcidin and Anemia in Surgical Critical Care: A Prospective Cohort Study

OBJECTIVE

Because anemia of inflammation is common in ICU patients and hepcidin is the key regulator of iron homeostasis, we examined time-dependent changes in hepcidin, erythropoietin, iron, and inflammatory markers in surgical ICU patients with anemia.

DESIGN

Prospective single-center clinical noninterventional study.

SETTING

Surgical ICUs; U.S. university hospital.

PATIENTS

One hundred surgical adult ICU patients.

MEASUREMENTS AND MAIN RESULTS

Time-dependent changes in serum hepcidin, hematologic, and erythropoietic studies were performed on ICU admission and at serial time-points through day 28, and correlated with hematologic and iron parameters and inflammatory response. Median serum hepcidin levels were significantly increased at ICU admission and decreased over time (144-36 ng/mL; p < 0.0001). Despite increased reticulocyte counts (1.3-2.9%), mean serum erythropoietin levels remained low (29-44 mU/mL) and hemoglobin did not significantly change. Hepcidin was positively correlated with RBC transfusion, C-reactive protein, interleukin-6, ferritin, and negatively correlated with iron, total iron binding capacity, transferrin, and reticulocyte response. Hepcidin did not correlate with tumor necrosis factor-α serum concentrations. Regression analyses confirmed that ferritin, C-reactive protein, and reticulocyte number were predictive of same-day hepcidin; hepcidin and C-reactive protein were predictive of same-day reticulocyte count.

CONCLUSIONS

Hepcidin serum concentrations are markedly increased on ICU admission, and decrease significantly over the course of the ICU stay (28 d). Decreased hepcidin concentrations are associated with increased reticulocyte response and decreased inflammatory response reflected by decreased interleukin-6 and C-reactive protein concentrations, but not with anemia resolution.

Acute effects of high-intensity exercise on hematological and iron metabolic parameters in elite male and female dragon boating athletes

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.

Baseline hepcidin measurement in the differential diagnosis of anaemia for elderly patients and its correlation with the increment of transferrin saturation following an oral iron absorption test

Background

Anaemia is often multifactorial in the elderly, with a frequent association between iron deficiency anaemia (IDA) and anaemia of chronic disease (ACD). The primary objective of our study was to investigate whether baseline hepcidin measurement could be useful for identifying iron deficiency (ID) in anaemic elderly patients. The secondary objective was to assess whether baseline hepcidin concentrations correlated with the relative increase of transferrin saturation (TS) after an oral iron absorption test (OIAT).

Methods

Blood samples were collected between 7:30 am and 10:00 am in 328 geriatric outpatients, 102 underwent the OIAT. Types of anaemia were classified according biochemical and clinical criteria. TS and hepcidin were measured at baseline and 4 h after the iron dose. The ability of baseline hepcidin measurement to highlight ID in elderly anaemic patients was assessed using a receiver operator curve (ROC) analysis. Correlations between baseline hepcidin levels and the increment of TS following the OIAT were investigated using the Spearman coefficient.

Results

Among 328 included patients, 78 (23.8%) suffered from anaemia; 13 (4.0%), 19 (5.8%), 27 (8.2%) and 19 (5.8%) patients fulfilled criteria for IDA, IDA/ACD, ACD and unexplained anaemia, respectively. By multivariable analysis, creatinine, C-reactive protein, ferritin, Delta TS and Delta hepcidin were independently associated with baseline hepcidin concentrations. The area under the ROC curve (95% confidence interval) was 0.900 (0.830–0.970) for baseline hepcidin measurement. Baseline hepcidin levels correlated negatively with the relative increase in TS with a Spearman coefficient of −0.742.

Conclusions

Baseline hepcidin levels could be a useful tool to identify ID in anaemic elderly patients and may predict acute iron response following OIAT.

Iron Absorption from Iron-Enriched Aspergillus oryzae Is Similar to Ferrous Sulfate in Healthy Female Subjects

BACKGROUND

Iron deficiency anemia (IDA) remains a global health issue, affecting mainly children and adolescent and pregnant women. Because of problems associated with current iron compounds used in both supplementation and fortification areas, there is an emerging interest in new natural iron sources to combat IDA.

OBJECTIVE

The objective of this study was to compare the iron absorption of iron-enriched Aspergillus oryzae [Aspiron (ASP)] with FeSO4 in humans.

METHODS

Iron absorption was assessed using stable isotope and serum iron response methods after oral intake of iron by healthy women in 2 separate studies. In the first study, ASP was intrinsically labelled with 58Fe into a dry form containing 8% iron. Subjects (n = 16, 18-35 y) were randomly assigned to consume liquid semipurified meals labelled with 2 stable iron isotopes, 57FeSO4 (10 mg) and ASP containing 2 mg 58Fe and 8 mg natural abundance iron, in 2 visits. Isotope enrichment was measured 2 wk after the last meal was eaten. In the second study, 17 subjects were randomly assigned to consume a test meal with 3 iron supplements during 3 separate visits: FeSO4, 10 mg Fe, and ASP in 2 iron doses, 10 mg and 20 mg. Changes in serum iron were measured at regular intervals for 4 h after supplementation.

RESULTS

The first study showed that the difference in iron absorption from FeSO4 and ASP was not significant (17.18% ± 14.2% compared to 15.14% ± 12.3%; P = 0.07). The results of the second study suggested that the iron from ASP was released slowly compared to FeSO4 and the area under the curve did not reflect the absorption of ASP iron, but rather the rate of iron release.

CONCLUSIONS

Iron-enriched A. oryzae has high relative bioavailability and may cause lower iron surges into the blood compared to FeSO4.

Evidence-based and consensus clinical practice guidelines for the iron treatment of restless legs syndrome/Willis-Ekbom disease in adults and children: an IRLSSG task force report

BACKGROUND

Brain iron deficiency has been implicated in the pathophysiology of RLS, and current RLS treatment guidelines recommend iron treatment when peripheral iron levels are low. In order to assess the evidence on the oral and intravenous (IV) iron treatment of RLS and periodic limb movement disorder (PLMD) in adults and children, the International Restless Legs Syndrome Study Group (IRLSSG) formed a task force to review these studies and provide evidence-based and consensus guidelines for the iron treatment of RLS in adults, and RLS and PLMD in children.

METHODS

A literature search was performed to identify papers appearing in MEDLINE from its inception to July 2016. The following inclusion criteria were used: human research on the treatment of RLS or periodic limb movements (PLM) with iron, sample size of at least five, and published in English. Two task force members independently evaluated each paper and classified the quality of evidence provided.

RESULTS

A total of 299 papers were identified, of these 31 papers met the inclusion criteria. Four studies in adults were given a Class I rating (one for IV iron sucrose, and three for IV ferric carboxymaltose); only Class IV studies have evaluated iron treatment in children. Ferric carboxymaltose (1000 mg) is effective for treating moderate to severe RLS in those with serum ferritin <300 μg/l and could be used as first-line treatment for RLS in adults. Oral iron (65 mg elemental iron) is possibly effective for treating RLS in those with serum ferritin ≤75 μg/l. There is insufficient evidence to make conclusions on the efficacy of oral iron or IV iron in children.

CONCLUSIONS

Consensus recommendations based on clinical practice are presented, including when to use oral iron or IV iron, and recommendations on repeated iron treatments. New iron treatment algorithms, based on evidence and consensus opinion have been developed.

Increased Small Intestine Expression of Non-Heme Iron Transporters in Morbidly Obese Patients With Newly Diagnosed Type 2 Diabetes

SCOPE

To investigate intestinal markers of iron absorption in morbidly obese subjects according to glucose tolerance.

METHODS AND RESULTS

Gene expression of both non-heme (SLC40A1 (ferroportin), SLC11A2) and heme iron (SLC46A1 (HCP1), HMOX1) transporters is analyzed in 38 small intestine tissue samples [11 with normal glucose tolerance, 14 with glucose intolerance (GI), and 13 with newly diagnosed type 2 diabetes (T2D)]. SLC40A1 (r = 0.43, p = 0.008) and SLC11A2 (r = 0.35, p = 0.03) mRNA levels are positively correlated with ferritin-to-hepcidin ratio and with fasting glucose, being significantly increased in patients with T2D. Only ferroportin is negatively associated with serum hepcidin (r = -0.617, p < 0.0001). In multivariate regression analysis, fasting glucose contributes independently to intestinal SLC40A1 (p = 0.009) and SLC11A2 (p = 0.04) variance after controlling for age, sex, and BMI. When circulating hepcidin is incorporated into the model, fasting glucose contributes significantly and independently to intestinal SLC40A1 (p = 0.02), but not to SLC11A2 (p = 0.07) variance. SLC46A1 and HMOX1 are similar in all groups.

CONCLUSION

The expression of ferroportin and SLC11A2 is increased in the intestine of patients with T2D in association with iron stores and serum hepcidin levels. Increased intestinal iron absorption is a potential mechanism that could explain the increased body iron stores frequently observed in patients with T2D.

Prediction of human iron bioavailability using rapid c-ELISAs for human plasma hepcidin

BACKGROUND

Hepcidin is the central systemic regulator of iron metabolism, but its quantification in biological fluids is challenging. Rapid, accurate and user-friendly methods are needed. Our aim was to assess the ability of hepcidin as measured by three different c-ELISA assays to predict iron bioavailability in humans.

METHODS

The three assays used were commercially available DRG and Peninsula assays and the c-ELISA method performed at Radboud University Medical Centre, Nijmegen, The Netherlands (Hepcidinanalysis.com), validated by comparative measurements with time-of-flight mass spectrometry. We analyzed plasma samples (n=37) selected to represent a broad range of hepcidin concentrations from a subgroup of healthy, iron-depleted women in a study assessing fractional absorption from iron supplements.

RESULTS

In single regressions, all three c-ELISA assays were predictors of fractional iron absorption: R2=0.363 (DRG), R2=0.281 (Peninsula) and R2=0.327 (Hepcidinanalysis.com). In multiple regressions, models including hepcidin measured with either DRG-, Peninsula or Hepcidinanalysis.com explained 55.7%, 44.5% and 52.5% of variance in fractional absorption, and hepcidin was a strong predictor of fractional absorption irrespective of the hepcidin assays used. However, we found significant differences in absolute values for hepcidin between different methods. Both the DRG assay's (y=0.61x+0.87; R2=0.873) and the Peninsula assay's measurements (y=1.88x+0.62; R2=0.770) were correlated with Hepcidinanalysis.com.

CONCLUSIONS

The biological variability in plasma hepcidin, (inter-sample CV) was 5-10-fold higher for both the Peninsula and DRG assay than the analytical variably (inter-run within-sample CV) suggesting substantial discriminatory power to distinguish biological hepcidin variation. Between methods, prediction of iron bioavailability in generally healthy iron depleted subjects appears comparable.

Longitudinal Analysis of the Interaction Between Obesity and Pregnancy on Iron Homeostasis: Role of Hepcidin

BACKGROUND AND AIMS

When pregnancy occurs in obese women, two opposite mechanisms for iron homeostasis concur: increased need for available iron to support erythropoiesis and decreased iron mobilization from diets and stores due to obesity-related inflammation linked to overexpressed hepcidin. Few studies have examined the role of hepcidin on maternal iron homeostasis in the context of obese pregnancy. The aim of the study was to evaluate the combined effect of maternal obesity and pregnancy on hepcidin and maternal iron status while accounting for inflammation and iron supplementation.

METHODS

We conducted a secondary analysis of a cohort of pregnant women recruited from a referral obstetric hospital in Mexico City. Circulating biomarkers of iron status (hepcidin, ferritin [SF], transferrin receptor [sTfR], erythropoietin [EPO]), and inflammation (C-reactive protein [CRP], tumor necrosis factor-[TNF]α, and interleukin-[IL]6) were determined monthly throughout pregnancy. Repeated measures ANOVA and logistic regression models were used for statistics.

RESULTS

Twenty-three obese (Ob) and 25 lean (Lc) women were studied. SF and hepcidin declined, and EPO and sTfR increased throughout pregnancy in both groups. sTfR increased more in Ob than in Lc (p = 0.024). The smallest hepcidin decline occurred in iron-supplemented Ob women compared to non-supplemented Lc women (p = 0.022). The risk for iron deficiency at the end of pregnancy was higher for Ob than for Lc (OR = 4.45, 95% CI = 2.07-9.58) after adjusting for iron supplementation and hepcidin concentration.

CONCLUSION

Pre-gestational obesity increases the risk of maternal iron deficiency despite iron supplementation. Overexpressed hepcidin appears to be a potential mechanism.

Perspective: What Makes It So Difficult to Mitigate Worldwide Anemia Prevalence?

Anemia can be related to decreased production or increased loss of erythrocytes, or both, leading to many underlying and often overlapping causes. A largely cereal-based diet with plenty of phytates, polyphenols, and other ligands that inhibit intestinal iron absorption predominated in preindustrial Europe and predominates in present-day developing countries alike. In both situations, we find poor hygienic conditions, which frequently lead to anemia of inflammation. The large number of possible causes and their interaction shows why it is so difficult to mitigate anemia prevalence. Diagnostic biomarkers are required to differentiate the different types of anemia and to treat them appropriately. Some of them are well established in adults [e.g., concentrations of serum ferritin, soluble transferrin receptor (sTfR), and serum iron or the ratio of sTfR to log ferritin]. Others, such as serum hepcidin, hold considerable promise, although they are not yet widely used. A particular issue is to establish reference values for biomarkers in infants and children at different ages. The fact that resource-rich postindustrial societies have a very low prevalence of iron-deficiency anemia offers hope that common types of anemia can be eliminated. In contrast, inborn forms of anemia, such as thalassemia, and anemias related to underlying diseases (e.g., bleeding tumors or peptic ulcers, gynecologic blood losses, or renal diseases) require an operational health system to be addressed appropriately.

Iron homeostasis after blood transfusion in stable preterm infants - an observational study

AIM

To evaluate the short-term effects of blood transfusion on iron status [hemoglobin, ferritin, soluble transferrin receptor (sTfR), and reticulocyte count], hepcidin, and erythropoietin in stable preterm infants.

METHOD

Sixty-three preterm infants treated with red blood cell transfusions (RBCTs) were included. Venous blood samples were collected before and within 24 h after each transfusion.

RESULTS

Hemoglobin concentration increased after RBCT (7.2±1.2 g/dL vs. 13.7±2.3 g/dL, P=0.02), as well as ferritin [131 (63-110.4) ng/mL vs. 211 (125.7-299.2) ng/mL, P=0.05); reticulocyte count decreased. sTfR did not change. Hepcidin serum levels increased from 37.5 (21.3-84.7) ng/mL to 72.6 (31.3-126.2) ng/mL, (P=0.04) and erythropoietin decreased (48±19 pg/mL vs. 29±17 pg/mL, P=0.06) after RBCT. A positive linear correlation was found (R2=0.76, P=0.0001) between hepcidin and ferritin levels of post-minus-pre RBCT. Hepcidin levels increased significantly in preterm infants who received RBCT after 1 month of age compared to those who received RBCT at <1 month (P=0.03). No correlation was found between gestational age, weight appropriate for age, or length of blood storage and hepcidin levels.

CONCLUSION

Preterm infants can control iron levels by regulating hepcidin and decreasing erythropoietin. This ability varies with postnatal age.

Hepcidin is a Better Predictor of Iron Stores in Premenopausal Women than Blood Loss or Dietary Intake

The relationship between dietary intake, circulating hepcidin and iron status in free-living premenopausal women has not been explored. This cross-sectional study aimed to identify dietary determinants of iron stores after accounting for blood loss and to determine whether iron intake predicts iron stores independently of hepcidin in a sample of Australian women. Three hundred thirty eight women aged 18-50 years were recruited. Total intake and food sources of iron were determined via food frequency questionnaire; the magnitude of menstrual losses was estimated by self-report; and blood donation volume was quantified using blood donation records and self-reported donation frequency. Serum samples were analysed for ferritin, hepcidin and C-reactive protein concentrations. Linear regression was used to investigate associations. Accounting for blood loss, each 1 mg/day increase in dietary iron was associated with a 3% increase in iron stores (p = 0.027); this association was not independent of hepcidin. Hepcidin was a more influential determinant of iron stores than blood loss and dietary factors combined (R² of model including hepcidin = 0.65; R² of model excluding hepcidin = 0.17, p for difference <0.001), and increased hepcidin diminished the positive association between iron intake and iron stores. Despite not being the biggest contributor to dietary iron intake, unprocessed meat was positively associated with iron stores, and each 10% increase in consumption was associated with a 1% increase in iron stores (p = 0.006). No other dietary factors were associated with iron stores. Interventions that reduce hepcidin production combined with dietary strategies to increase iron intake may be important means of improving iron status in women with depleted iron stores.

Serum Hepcidin and Iron Absorption in Paediatric Inflammatory Bowel Disease

BACKGROUND AND AIMS

We sought to correlate hepcidin levels in inflammatory bowel disease [IBD] children with disease activity, inflammatory markers, and iron load test [ILT] and to compare IBD patients with coeliac and healthy patients.

METHODS

Between December 2012 and June 2013, 145 subjects [50 IBD patients, 45 coeliac patients and 50 healthy controls] were included in the study. All patients underwent the following examinations: blood count, iron status, erythropoiesis parameters, serum hepcidin, C-reactive protein [CRP], and erythrocyte sedimentation rate [ESR]. In order to evaluate the efficacy of iron absorption, ILT was performed in IBD patients. Disease activity indexes and IBD duration, localisation, and therapy were also evaluated, and a faecal sample for calprotectin collected.

RESULTS

Serum hepcidin was significantly higher in IBD patients with active disease compared with both coeliac and healthy patients [p = 0.005, p = 0.003 respectively]. In a multivariate logistic regression model, having a Paediatric Crohn's Disease Activity Index [PCDAI] / Paediatric Ulcerative Colitis Activity Index [PUCAI] ≥ 30 resulted in the only variable independently associated with a positive serum hepcidin (odds ratio [OR] = 6.87; 95% confidence interval [CI] 1.4-33, p = 0.01]]. Patients with iron malabsorption [IM] showed higher values of ESR, CRP, and hepcidin [p = 0.02, p = 0.001, and p = 0.06, respectively]. Eight out of 12 [66.7%] children with IM showed an active disease compared with 6/31 [19.3%] children with normal ILT [p = 0.01]. Hepcidin levels correlated negatively with ILT [r = -0.451, p = 0.002], and positively with ferritin and CRP [r = 0.442, p = 0.0001; r = 0.243, p = 0.009, respectively]

CONCLUSIONS

Our study demonstrates that serum hepcidin is increased in IBD children with active disease and it is responsible for IM.

Hepcidin in the diagnosis of iron disorders

The discovery of the iron-regulatory hormone hepcidin in 2001 has revolutionized our understanding of iron disorders, and its measurement should advance diagnosis/treatment of these conditions. Although several assays have been developed, a gold standard is still lacking, and efforts toward harmonization are ongoing. Nevertheless, promising applications can already be glimpsed, ranging from the use of hepcidin levels for diagnosing iron-refractory iron deficiency anemia to global health applications such as guiding safe iron supplementation in developing countries with high infection burden.

Inclusion of ancient Latin-American crops in bread formulation improves intestinal iron absorption and modulates inflammatory markers

This study compares iron (Fe) absorption in Fe-deficient animals from bread formulations prepared by substitution of white wheat flour (WB) by whole wheat flour (WWB), amaranth flour (Amaranthus hypochondriacus, 25%) (AB) and quinoa flour (Chenopodium quinoa, 25%) (QB), or chia flour (Salvia hispanica L, 5%) (ChB).

Iron Absorption from an Intrinsically Labeled Lentil Meal Is Low but Upregulated in Women with Poor Iron Status

BACKGROUND

Low iron absorption from important staple foods may contribute to iron deficiency in developing countries. To date, few studies have examined the iron bioavailability of pulse crops as commonly prepared and consumed by humans.

OBJECTIVE

The objectives were to characterize the iron absorption from a test meal of intrinsically labeled (57)Fe lentils prepared as dal, to compare the bioavailability of iron from (57)Fe in dal with that observed for a reference dose of (58)Fe as ferrous sulfate, and to assess associations between iron absorption and iron status indicators.

METHODS

This crossover study included 19 nonpregnant women (n = 6 anemic; hemoglobin: <12.0 g/dL) who consumed 2 test meals on consecutive days in a counter-balanced order, ferrous sulfate (7 mg FeSO4 plus 1 mg (58)Fe) and 330 g dal (lentils enriched to 85.1% with (57)Fe, 8 mg native (57)Fe). Iron absorption was determined by analyzing blood samples taken 14 d after dosing with the use of magnetic sector thermal ionization mass spectrometry.

RESULTS

We found that the mean iron absorption from the dal was 2.20% ± 3.40% and was significantly lower than the 23.6% ± 13.2% observed from the same iron load given as ferrous sulfate (P < 0.001). Absorption of non-heme iron from dal and from ferrous sulfate was inversely associated with serum ferritin (SF; r = -0.50, P = 0.05 and r = -0.81, P < 0.001, respectively) and serum hepcidin (r = -0.45, P = 0.05 and r = -0.60, P = 0.007, respectively). Anemic women absorbed more iron from either source (1.20% from dal, P = 0.10; 18.3% from ferrous sulfate, P = 0.001) compared with women who were iron replete.

CONCLUSIONS

Iron absorption from the dal was low overall but upregulated in anemic women. Both SF and hepcidin were inversely associated with iron absorption from both a supplemental and a food-based non-heme iron source in nonanemic and anemic women.

An insight into the relationships between prohepcidin, iron deficiency anemia, and interleukin-6 values in pediatric Helicobacter pylori gastritis

The link between Helicobacter pylori and iron deficiency (ID) or iron deficiency anemia (IDA) has been investigated recently. We suggested that IDA/ID associated with H. pylori infection might be mediated by inflammation-driven hepcidin production. Patients with complaints of recurrent abdominal pain and dyspepsia aged between 7-16 years were included in this study. Patients were divided into two groups according to H. pylori status in upper gastrointestinal endoscopy. Group I who had H. pylori gastritis (n=50) received triple antibiotic therapy. Group II (n=50) who had H. pylori-negative gastritis only received proton pump inhibitor. Thirty healthy children with the similar age and gender were included in the study as a control group. Complete blood count, serum iron levels, iron-binding capacity, ferritin levels, prohepcidin and interleukin-6 (IL-6) values were evaluated in all children at the first visit. Initial tests were repeated after H. pylori eradication. Initial levels of ferritin (p=0.002), prohepcidin (p=0.003), and IL-6 (p=0.004) were found significantly lower in group I compared to group II and the control group. The mean prohepcidin level was lower in the anemic H. pylori-positive group than in non-anemic H. pylori-positive group; however, the difference was not statistically significant. While significant increases in hematocrit and mean corpuscular volume were observed, no significant difference was found in serum ferritin, prohepcidin, or IL-6 level after eradication treatment in H. pylori-positive group.

CONCLUSION

H. pylori-induced gastritis appears to cause an increase in prohepcidin levels and a decrease in ferritin levels, supporting our hypothesis; but this relationship has not been proven.

Natural selection on HFE in Asian populations contributes to enhanced non-heme iron absorption

BACKGROUND

HFE, a major regulator of iron (Fe) homeostasis, has been suggested to be under positive selection in both European and Asian populations. While the genetic variant under selection in Europeans (a non-synonymous mutation, C282Y) has been relatively well-studied, the adaptive variant in Asians and its functional consequences are still unknown. Identifying the adaptive HFE variants in Asians will not only elucidate the evolutionary history and the genetic basis of population difference in Fe status, but also assist the future practice of genome-informed dietary recommendation.

RESULTS

Using data from the International HapMap Project, we confirmed the signatures of positive selection on HFE in Asian populations and identified a candidate adaptive haplotype that is common in Asians (52.35-54.71%) but rare in Europeans (5.98%) and Africans (4.35%). The T allele at tag SNP rs9366637 (C/T) captured 95.8% of this Asian-common haplotype. A significantly reduced HFE expression was observed in individuals carrying T/T at rs9366637 compared to C/C and C/T, indicating a possible role of gene regulation in adaptation. We recruited 57 women of Asian descent and measured Fe absorption using stable isotopes in those homozygous at rs9366637. We observed a 22% higher absorption in women homozygous for the Asian-common haplotype (T/T) compared to the control genotype (C/C). Additionally, compared with a group of age-matched Caucasian women, Asian women exhibited significantly elevated Fe absorption.

CONCLUSIONS

Our results indicate parallel adaptation of HFE gene in Europeans and Asians with different genetic variants. Moreover, natural selection on HFE may have contributed to elevated Fe absorption in Asians. This study regarding population differences in Fe homeostasis has significant medical impact as high Fe level has been linked to an increased disease risk of metabolic syndromes.

Differences in Relative Iron Bioavailability in Traditional Bangladeshi Meal Plans

Background

Iron deficiency is the most common nutrient deficiency worldwide. Large intakes of micronutrient-poor staple crops, coupled with low intakes of highly bioavailable dietary iron, are a major cause of this deficiency.

Objective

To examine the concentration and relative bioavailability of iron in several models ( n = 23) of traditional Bangladeshi meals (rice, lentils/dal, vegetable, and fish), as well as the effect of removal of the lentil seed coat on the nutritional quality of iron.

Methods

The relative bioavailability of iron was assessed by the in vitro/Caco-2 cell culture method, iron concentration by an inductively coupled argon-plasma emission spectrometer (ICAP-ES), and phytic acid concentration by colorimetric assay. The recipes contained 75% to 85% rice, 0% to 15% dal (containing whole or dehulled lentils), 0% to 15% vegetable curry, and 0% to 8% fish.

Results

While the iron concentrations of recipes containing dehulled dal were significantly lower than those of recipes containing whole dal ( p = .005), seed coat removal doubled relative iron bioavailability and increased phytic acid concentration ( p < .001). The addition of fish to the meals had no significant effect on relative iron bioavailability. Iron concentration and relative iron bioavailability were correlated in the recipes containing dehulled dal ( r = 0.48, p = .03), but not whole dal ( r = −0.047, p = .84).

Conclusions

The total amount of iron absorbed from traditional Bangladeshi meals is dependent upon iron concentration, and dehulling lentils removes inhibitory factors increasing iron uptake but also increases the density of phytic acid in the lentil sample. Thus, along with breeding for high iron concentration and bioavailability (i.e., biofortification), seed coat removal plus measures to lower phytic acid concentrations may be an important strategy to improve the bioavailability of iron in lentils and other pulse crops.

Duodenal absorption and tissue utilization of dietary heme and nonheme iron differ in rats

BACKGROUND

Dietary heme contributes to iron intake, yet regulation of heme absorption and tissue utilization of absorbed heme remains undefined.

OBJECTIVES

In a rat model of iron overload, we used stable iron isotopes to examine heme- and nonheme-iron absorption in relation to liver hepcidin and to compare relative utilization of absorbed heme and nonheme iron by erythroid (RBC) and iron storage tissues (liver and spleen).

METHODS

Twelve male Sprague-Dawley rats were randomly assigned to groups for injections of either saline or iron dextran (16 or 48 mg Fe over 2 wk). After iron loading, rats were administered oral stable iron in the forms of (57)Fe-ferrous sulfate and (58)Fe-labeled hemoglobin. Expression of liver hepcidin and duodenal iron transporters and tissue stable iron enrichment was determined 10 d postdosing.

RESULTS

High iron loading increased hepatic hepcidin by 3-fold and reduced duodenal expression of divalent metal transporter 1 (DMT1) by 76%. Nonheme-iron absorption was 2.5 times higher than heme-iron absorption (P = 0.0008). Absorption of both forms of iron was inversely correlated with hepatic hepcidin expression (heme-iron absorption: r = -0.77, P = 0.003; nonheme-iron absorption: r = -0.80, P = 0.002), but hepcidin had a stronger impact on nonheme-iron absorption (P = 0.04). Significantly more (57)Fe was recovered in RBCs (P = 0.02), and more (58)Fe was recovered in the spleen (P = 0.01).

CONCLUSIONS

Elevated hepcidin significantly decreased heme- and nonheme-iron absorption but had a greater impact on nonheme-iron absorption. Differential tissue utilization of heme vs. nonheme iron was evident between erythroid and iron storage tissues, suggesting that some heme may be exported into the circulation in a form different from that of nonheme iron.

Structural differences of prebiotic oligosaccharides influence their capability to enhance iron absorption in deficient rats

This study evaluates the influence of novel galacto-oligosaccharides derived from lactulose (GOS-Lu), kojibiose or 4'-galactosyl-kojibiose in hematological parameters of Fe homeostasis using Fe-deficient animals. Liver TfR-2, IL-6, NFκB and PPAR-γ expression (mRNA) were also determined by RT-qPCR analyses, and active hepcidin peptide production and short chain fatty acids by LC coupled to MS/MS or UV detection. Feeding animals with GOS-Lu or kojibiose together with FeCl3 increased hemoglobin (Hb) production (by 17%) and mean Hb concentration into erythrocytes relative to animals administered with FeCl3 alone (14.1% and 19.7%, respectively). Animals administered with prebiotics showed decreased plasmatic hepcidin levels, contributing to a higher intestinal absorption of the micronutrient. These data indicate that concurrent administration of these potentially prebiotic oligosaccharides together with a supplement of Fe ameliorates inflammation-mediated perturbations in the liver, according to the particular structure of the prebiotic compound, and result an attractive strategy to improve Fe absorption.

Hepcidin Profile of Anemic Adolescent Schoolgirls in Indonesia at the End of 12 Weeks of Iron Supplementation

Background

Iron deficiency is still the major nutritional problem in the developing world, and iron supplementation remains one of the most effective intervention strategies. Hepcidin, a newly discovered iron regulatory hormone, is an acute phase protein, and its role in iron supplementation has not been well explored.

Objective

To investigate the hepcidin profiles of anemic adolescent girls who had received weekly iron supplementation.

Methods

A cross-sectional study was conducted at the end of iron supplementation among adolescent schoolgirls ( n = 83) in Pramuka Island, Indonesia. All the girls were anemic at the beginning and received 60 mg of elemental iron twice weekly for 12 weeks. Hemoglobin, hepcidin, serum ferritin, and red cell parameters were measured, together with inflammation markers.

Results

At the end of the 12-week supplementation, 65.1% (n=64) of the girls were no longer anemic, but 43.4% ( n = 36) were still iron deficient. The rate of sub-clinical inflammation, measured by C-reactive protein (CRP) and α-1-acid glycoprotein (AGP), was 38.6% ( n = 32). Hepcidin was not correlated with either ferritin or red cell parameters. There was no association between hepcidin and the inflammatory markers CRP and AGP. The mean hepcidin concentration was 42.9 ± 17.9 ng/mL and was not significantly different between anemic and nonanemic girls (44.2 ± 14.9 and 42.3 ± 19.2 ng/mL, respectively; p = .708). However, hepcidin concentration was slightly higher in the iron replete-group than in the iron-deficient group (45.2 ± 20.0 and 39.3 ± 13.5 ng/mL, respectively), a suggestive trend that did not reach statistical significance ( p = .218).

Conclusions

Hepcidin concentrations tended to be higher among the subset of girls who responded poorly to iron supplementation as a consequence of increased subclinical inflammation. A longitudinal study should be conducted to explore the role of hepcidin in iron supplementation.

Systemic and tumor level iron regulation in men with colorectal cancer: a case control study

Background

Increased cellular iron exposure is associated with colorectal cancer (CRC) risk. Hepcidin, a liver peptide hormone, acts as the primary regulator of systemic iron status by blocking iron release from enterocytes into plasma. Concentrations are decreased during low iron status and increased during inflammation. The role of hepcidin and the factors influencing its regulation in CRC remains largely unknown. This study explored systemic and tumor level iron regulation in men with CRC.

Methods

The participants were 20 CRC cases and 20 healthy control subjects. Colonic tissue (adenocarcinoma [cases] healthy mucosa [controls]) was subjected to quantitative PCR (hepcidin, iron transporters and IL-6) and Perls’ iron staining. Serum was analyzed using ELISA for hepcidin, iron status (sTfR) and inflammatory markers (CRP, IL-6, TNF-α). Anthropometrics, dietary iron intake and medical history were obtained.

Results

Cases and controls were similar in demographics, medication use and dietary iron intake. Systemically, cases compared to controls had lower iron status (sTfR: 21.6 vs 11.8 nmol/L, p < 0.05) and higher marker of inflammation (CRP: 8.3 vs 3.4 μg/mL, p < 0.05). Serum hepcidin was mildly decreased in cases compared to controls; however, it was within the normal range for both groups. Within colonic tissue, 30% of cases (6/20) presented iron accumulation compared to 5% of controls (1/20) (χ² = 5.0; p < 0.05) and higher marker of inflammation (IL-6: 9.4-fold higher compared to controls, p < 0.05). Presence of adenocarcinoma iron accumulation was associated with higher serum hepcidin (iron accumulation group 80.8 vs iron absence group 22.0 ng/mL, p < 0.05).

Conclusions

While CRC subjects had serum hepcidin concentrations in the normal range, it was higher given their degree of iron restriction. Inappropriately elevated serum hepcidin may reduce duodenal iron absorption and further increase colonic adenocarcinoma iron exposure. Future clinical studies need to assess the appropriateness of dietary iron intake or iron supplementation in patients with CRC.

Erythropoiesis-driven regulation of hepcidin in human red cell disorders is better reflected through concentrations of soluble transferrin receptor rather than growth differentiation factor 15

Growth differentiation factor 15 (GDF-15) is a bone marrow-derived cytokine whose ability to suppress iron regulator hepcidin in vitro and increased concentrations found in patients with ineffective erythropoiesis (IE)suggest that hepcidin deficiency mediated by GDF-15 may be the pathophysiological explanation for nontransfusional iron overload. We aimed to compare GDF-15 production in anemic states with different types of erythropoietic dysfunction. Complete blood counts, biochemical markers of iron status, plasma hepcidin, GDF-15, and known hepcidin regulators [interleukin-6 and erythropoietin (EPO)] were measured in 87 patients with red cell disorders comprising IE and hemolytic states: thalassemia, sickle cell anemia, and cobalamin deficiency. Healthy volunteers were also evaluated for comparison. Neither overall increased EPO,nor variable GDF-15 concentrations correlated with circulating hepcidin concentrations (P = 0.265 and P = 0.872). Relative hepcidin deficiency was found in disorders presenting with concurrent elevation of GDF-15 and soluble transferrin receptor (sTfR), a biomarker of erythropoiesis, and sTfR had the strongest correlation with hepcidin (r(s) = 0.584, P < 0.0001). Our data show that high concentrations of GDF-15 in vivo are not necessarily associated with pathological hepcidin reduction, and hepcidin deficiency was only found when associated with sTfR overproduction. sTfR elevation may be a necessary common denominator of erythropoiesis-driven mechanisms to favor iron absorption in anemic states and appears a suitable target for investigative approaches to iron disorders.

Immunoassay-based serum hepcidin reference range measurements in healthy children: differences among age groups

BACKGROUND

Hepcidin is a peptide hormone that plays a key role in regulating iron absorption from the small intestine and body iron distribution. Alterations in hepcidin concentrations have been associated with chronic inflammatory conditions or inherited diseases of iron metabolism. The aim of our study was to evaluate healthy children in order to define normal reference range of serum hepcidin concentrations. The universal use of a reliable commercial ELISA kit gives the ability to compare our results with those from previous studies.

METHODS

We evaluated 180 healthy children (88 boys, mean age: 67.55 ± 39.26 months, median: 60, range: 24-156 months) aged 2-12 years, using an immunoassay kit.

RESULTS

Hepcidin median values were 46.94 ng/ml for boys and 46.79 ng/ml for girls. No significant differences were observed between boys and girls. There seem to be significantly higher values of hepcidin in older children (10-12 years old). This trend was constant and statistically significant in boys after gender and age group stratification. Although this trend was more prominent in girls, it was not statistically significant.

CONCLUSIONS

This study aims at setting up reference values for serum hepcidin concentrations in healthy pediatric population by using a well-established laboratory kit. The difference in hepcidin concentrations in older children could be attributed to different growth rates. Additionally, differences between values in adults and children could reflect alterations in iron metabolism between those two age groups.

Hepcidin, iron status, and inflammation variables among healthy pregnant women in the Turkish population

PURPOSE

To investigate hepcidin levels in each trimester and their association with other haematological variables and inflammation markers during normal pregnancy among low-risk pregnant women in rural Turkey.

METHOD

The series comprised 103 healthy Turkish primigravida women with a normal pregnancy. Blood samples were obtained at 11-14, 24-28 and 30-34 weeks of gestation. Haemoglobin, hematocrit, red cell indices, white blood cell count, platelet count, iron status indicators (plasma iron, transferrin, ferritin levels and iron binding capacity), serum hepcidin, interleukin-6 and C-reactive protein levels were analysed. The proportions were compared using Pearson's χ2 test or Friedman's test.

RESULTS

The mean serum hepcidin concentrations at 11-14, 24-28 and 30-34 weeks of gestation were as follows: 7.8 ± 3.4 ng/mL, 8.6 ± 3.1 ng/mL and 7.3 ± 3.0 ng/mL, respectively. The mean serum ferritin concentrations with median values at each trimester were 14.2 (11.5), 9.5 (8.8) and 11.2 (9.3), respectively. The mean serum CRP values at each trimester were 5.1 (4.0), 5.5 (4.6) and 6.0 (5.5), respectively. The serum hepcidin levels were not related to iron status or the haemoglobin, IL-6 or C-reactive protein levels.

CONCLUSIONS

There was no association between serum hepcidin and serum ferritin, IL-6 or CRP concentrations in each trimester among low-risk pregnant women.

Serum hepcidin levels in Helicobacter pylori-infected children with iron-deficiency anemia: a case-control study

Recently, hepcidin, an antimicrobial-like peptide hormone, has evolved as the master regulator of systemic iron homeostasis. Hepcidin integrates signals from diverse physiological inputs, forming a key connection between iron trafficking and response to infection. In this study, we aimed to investigate whether Helicobacter pylori infection modulates serum hepcidin level and response to oral iron therapy in children with iron-deficiency anemia. This was a case-control study including 60 children with iron-deficiency anemia (IDA; 30 H. pylori infected and 30 H. pylori noninfected) and 30 healthy children with comparable age and gender as the control group. Iron parameters including serum iron, ferritin, transferrin, total iron binding capacity, and transferrin saturation and serum hepcidin levels were assessed initially and after 3 months of oral iron therapy for IDA. Compared to the control group, serum hepcidin was significantly lower in H. pylori-noninfected children with IDA (P < 0.01) and significantly higher in H. pylori-infected children with IDA (P < 0.01). Hepcidin increased significantly in noninfected children with IDA after 3 months of oral iron therapy (P < 0.01). On the other hand, H. pylori-infected children showed nonsignificant change in hepcidin level after oral iron therapy (P > 0.05). Although hepcidin showed significant positive correlations with serum ferritin, hemoglobin (Hb), iron, and transferrin saturation in noninfected children with IDA (P < 0.01), it showed significant negative correlations with serum ferritin, Hb, iron, and transferrin saturation in H. pylori-infected children with IDA (P < 0.05). H. pylori infection upregulates serum hepcidin levels and was associated with diminished response to oral iron therapy in children with iron-deficiency anemia.

Associations between serum hepcidin, ferritin and Hb concentrations and type 2 diabetes risks in a Han Chinese population

Systemic Fe overload can contribute to abnormal glucose metabolism and the onset of type 2 diabetes (T2D). Although hepcidin is the master regulator of systemic Fe homeostasis, few studies have systematically evaluated the associations of serum hepcidin concentrations with Fe metabolism parameters and risks for the development of T2D. In this regard, whether hepcidin concentrations are associated with T2D remains controversial. We measured serum hepcidin and ferritin concentrations in a case–control study of 1259 Han Chinese participants to evaluate the possible associations of serum hepcidin concentrations with Fe metabolism parameters and risks of T2D. Individuals with diabetes (n 555) and control participants (n 704) were recruited and serum hepcidin and ferritin concentrations were quantified. Additionally, selected biochemical and anthropometric variables were determined. A logistic regression analysis was performed to evaluate the association of serum hepcidin and ferritin concentrations with T2D. A linear regression analysis was used to test for associations between serum hepcidin and ferritin concentrations and a number of clinical, demographic and diabetes-associated variables. We found that serum hepcidin concentrations correlated with Hb and serum ferritin concentrations. No differences in hepcidin concentrations were found between the group with diabetes and the control group. Hepcidin concentrations were not significantly correlated with T2D risk factors. We also found that serum ferritin concentrations were elevated in individuals with diabetes and were positively correlated with both Hb concentrations and T2D risk factors. The present findings suggest that serum ferritin concentrations correlate with T2D risk factors, while serum hepcidin concentrations are positively associated with Hb and serum ferritin concentrations, but do not correlate with T2D.