Regulation of iron metabolism by hepcidin

Maternal iron status during pregnancy compared with neonatal iron status better predicts placental iron transporter expression in humans

The placenta richly expresses nonheme and heme Fe transport proteins. To address the impact of maternal and neonatal Fe status and hepcidin on the regulation of these proteins, mRNA expression and protein abundance of nonheme and heme Fe transport proteins were evaluated in placental tissue from 154 adolescents. Regression analyses found maternal Fe status was significantly associated with multiple placental nonheme and heme transporters, whereas neonatal Fe status was related to only 3 heme transporters. Across statistical analyses, maternal Fe status was consistently associated with the placental nonheme Fe importer transferrin receptor 1 (TfR1). Protein abundance of TfR1 was related to midgestation maternal serum ferritin (SF) (β = -0.32; P = 0.005) and serum TfR (β = 0.25; P = 0.024). Protein abundance of the heme importer, proton-coupled folate transporter, was related to neonatal SF (β = 0.30; P = 0.016) and serum TfR (β = -0.46; P < 0.0001). Neonatal SF was also related to mRNA expression of the heme exporter feline leukemia virus subgroup C receptor 1 (β = -0.30; P = 0.004). In summary, maternal Fe insufficiency during pregnancy predicts increased expression of the placental nonheme Fe transporter TfR1. Associations between placental heme Fe transporters and neonatal Fe status require further study.-Best, C. M., Pressman, E. K., Cao, C., Cooper, E., Guillet, R., Yost, O. L., Galati, J., Kent, T. R., O'Brien, K. O. Maternal iron status during pregnancy compared with neonatal iron status better predicts placental iron transporter expression in humans.

Micronutrient intake, from diet and supplements, and association with status markers in pre- and post-RYGB patients

BACKGROUND & AIMS

Roux-en-Y gastric bypass (RYGB) is associated with an increased risk for micronutrient deficiencies. This study aimed to assess total (dietary and supplement) intake and association with iron (including hepcidin), vitamin B₁₂, vitamin C and zinc status markers before and after Roux-en-Y gastric bypass (RYGB).

METHODS

This prospective study included patients with a planned RYGB in University Hospitals Leuven, Belgium; who were followed until 12 months post-RYGB. Patients completed an estimated dietary record of two non-consecutive days before and 1, 3, 6 and 12 months post-RYGB and supplement/drug use was registered. Associations between total micronutrient intake and status markers were analyzed.

RESULTS

Fifty-four patients (21 males; mean age: 48.0 [95%CI 46.6; 49.3] years; mean preoperative BMI: 40.4 [95%CI 39.4; 41.4] kg/m²) were included. One month post-RYGB, usual dietary intake of the studied micronutrients was significantly decreased compared to pre-RYGB, but gradually increased until 12 months post-RYGB, remaining below baseline values. By including micronutrient supplement intake, 12 months post-RYGB values were higher than baseline, except for zinc. Hemoglobin, ferritin, vitamin B₁₂ and C-reactive protein serum concentrations were significantly decreased and transferrin saturation and mean corpuscular volume were significantly increased 12 months post-RYGB. Serum hepcidin concentration was significantly decreased 6 months post-RYGB.

CONCLUSIONS

Medical nutritional therapy is essential following RYGB as dietary intake of iron, vitamin B₁₂, vitamin C, copper and zinc was markedly decreased postoperatively and some patients still had an inadequate total intake one year post-RYGB.

Microgeographic Proteomic Networks of the Human Colonic Mucosa and Their Association With Inflammatory Bowel Disease

BACKGROUND & AIMS

Interactions between mucosal cell types, environmental stressors, and intestinal microbiota contribute to pathogenesis in inflammatory bowel disease (IBD). Here, we applied metaproteomics of the mucosal-luminal interface to study the disease-related biology of the human colonic mucosa.

METHODS

We recruited a discovery cohort of 51 IBD and non-IBD subjects endoscopically sampled by mucosal lavage at 6 colonic regions, and a validation cohort of 38 no-IBD subjects. Metaproteome data sets were produced for each sample and analyzed for association with colonic site and disease state using a suite of bioinformatic approaches. Localization of select proteins was determined by immunoblot analysis and immunohistochemistry of human endoscopic biopsy samples.

RESULTS

Co-occurrence analysis of the discovery cohort metaproteome showed that proteins at the mucosal surface clustered into modules with evidence of differential functional specialization (eg, iron regulation, microbial defense) and cellular origin (eg, epithelial or hemopoietic). These modules, validated in an independent cohort, were differentially associated spatially along the gastrointestinal tract, and 7 modules were associated selectively with non-IBD, ulcerative colitis, and/or Crohn's disease states. In addition, the detailed composition of certain modules was altered in disease vs healthy states. We confirmed the predicted spatial and disease-associated localization of 28 proteins representing 4 different disease-related modules by immunoblot and immunohistochemistry visualization, with evidence for their distribution as millimeter-scale microgeographic mosaic.

CONCLUSIONS

These findings suggest that the mucosal surface is a microgeographic mosaic of functional networks reflecting the local mucosal ecology, whose compositional differences in disease and healthy samples may provide a unique readout of physiologic and pathologic mucosal states.

Safety, pharmacokinetics and pharmacodynamics of the anti-hepcidin Spiegelmer lexaptepid pegol in healthy subjects

BACKGROUND AND PURPOSE

Anaemia of chronic disease is characterized by impaired erythropoiesis due to functional iron deficiency, often caused by excessive hepcidin. Lexaptepid pegol, a pegylated structured l-oligoribonucleotide, binds and inactivates hepcidin.

EXPERIMENTAL APPROACH

We conducted a placebo-controlled study on the safety, pharmacokinetics and pharmacodynamics of lexaptepid after single and repeated i.v. and s.c. administration to 64 healthy subjects at doses from 0.3 to 4.8 mg·kg(-1) .

KEY RESULTS

After treatment with lexaptepid, serum iron concentration and transferrin increased dose-dependently. Iron increased from approximately 20 μmol·L(-1) at baseline by 67% at 8 h after i.v. infusion of 1.2 mg·kg(-1) lexaptepid. The pharmacokinetics showed dose-proportional increases in peak plasma concentrations and moderately over-proportional increases in systemic exposure. Lexaptepid had no effect on hepcidin production or anti-drug antibodies. Treatment with lexaptepid was generally safe and well tolerated, with mild and transient transaminase increases at doses ≥2.4 mg·kg(-1) and with local injection site reactions after s.c. but not after i.v. administration.

CONCLUSIONS AND IMPLICATIONS

Lexaptepid pegol inhibited hepcidin and dose-dependently raised serum iron and transferrin saturation. The compound is being further developed to treat anaemia of chronic disease.

RNA-Seq reveals common and unique PXR- and CAR-target gene signatures in the mouse liver transcriptome

The pregnane X receptor (PXR) and constitutive androstane receptor (CAR) are well-known xenobiotic-sensing nuclear receptors with overlapping functions. However, there lacks a quantitative characterization to distinguish between the PXR and CAR target genes and signaling pathways in the liver. The present study performed a transcriptomic comparison of the PXR- and CAR-targets using RNA-Seq in livers of adult wild-type mice that were treated with the prototypical PXR ligand PCN (200mg/kg, i.p. once daily for 4days in corn oil) or the prototypical CAR ligand TCPOBOP (3mg/kg, i.p., once daily for 4days in corn oil). At the given doses, TCPOBOP differentially regulated many more genes (2125) than PCN (212), and 147 of the same genes were differentially regulated by both chemicals. As expected, the top pathways differentially regulated by both PCN and TCPOBOP were involved in xenobiotic metabolism, and they also up-regulated genes involved in retinoid metabolism, but down-regulated genes involved in inflammation and iron homeostasis. Regarding unique pathways, PXR activation appeared to overlap with the aryl hydrocarbon receptor signaling, whereas CAR activation appeared to overlap with the farnesoid X receptor signaling, acute-phase response, and mitochondrial dysfunction. The mRNAs of differentially regulated drug-processing genes (DPGs) partitioned into three patterns, namely TCPOBOP-induced, PCN-induced, as well as TCPOBOP-suppressed gene clusters. The cumulative mRNAs of the differentially regulated DPGs, phase-I and -II enzymes, as well as efflux transporters were all up-regulated by both PCN and TCPOBOPOP, whereas the cumulative mRNAs of the uptake transporters were down-regulated only by TCPOBOP. The absolute mRNA abundance in control and receptor-activated conditions was examined in each DPG category to predict the contribution of specific DPG genes in the PXR/CAR-mediated pharmacokinetic responses. The preferable differential regulation by TCPOBOP in the entire hepatic transcriptome correlated with a marked change in the expression of many DNA and histone epigenetic modifiers. In conclusion, the present study has revealed known and novel, as well as common and unique targets of PXR and CAR in mouse liver following pharmacological activation using their prototypical ligands. Results from this study will further support the role of these receptors in regulating the homeostasis of xenobiotic and intermediary metabolism in the liver, and aid in distinguishing between PXR and CAR signaling at various physiological and pathophysiological conditions. This article is part of a Special Issue entitled: Xenobiotic nuclear receptors: New Tricks for An Old Dog, edited by Dr. Wen Xie.

Treatment with anti-IL-6 receptor antibody prevented increase in serum hepcidin levels and improved anemia in mice inoculated with IL-6-producing lung carcinoma cells

Background

Hepcidin, a key regulator of iron metabolism, is produced mainly by interleukin-6 (IL-6) during inflammation. A mechanism linking cancer-related anemia and IL-6 through hepcidin production is suggested. To clarify the hypothesis that overproduction of IL-6 elevates hepcidin levels and contributes to the development of cancer-related anemia, we evaluated anti-IL-6 receptor antibody treatment of cancer-related anemia in an IL-6–producing human lung cancer xenograft model.

Methods

Nude mice were subcutaneously inoculated with cells of the IL-6–producing human lung cancer cell line LC-06-JCK and assessed as a model of cancer-related anemia. Mice bearing LC-06-JCK were administered rat anti-mouse IL-6 receptor antibody MR16-1 and their serum hepcidin levels and hematological parameters were determined.

Results

LC-06-JCK–bearing mice developed anemia according to the production of human IL-6 from xenografts, with decreased values of hemoglobin, hematocrit, and mean corpuscular volume (MCV) compared to non–tumor-bearing (NTB) mice. LC-06-JCK–bearing mice showed decreased body weight and serum albumin with increased serum amyloid A. MR16-1 treatment showed significant inhibition of decreased body weight and serum albumin levels, and suppressed serum amyloid A level. There was no difference in tumor volume between MR16-1-treated mice and immunoglobulin G (IgG)-treated control mice. Decreased hemoglobin, hematocrit, and MCV in LC-06-JCK–bearing mice was significantly relieved by MR16-1 treatment. LC-06-JCK–bearing mice showed high red blood cell counts and erythropoietin levels as compared to NTB mice, whereas MR16-1 treatment did not affect their levels. Serum hepcidin and ferritin levels were statistically elevated in mice bearing LC-06-JCK. LC-06-JCK–bearing mice showed lower values of MCV, mean corpuscular hemoglobin (MCH), and serum iron as compared to NTB mice. Administration of MR16-1 to mice bearing LC-06-JCK significantly suppressed levels of both serum hepcidin and ferritin, with increased values of MCV and MCH.

Conclusions

Our results suggest that overproduction of hepcidin by IL-6 signaling might be a major factor that leads to functionally iron-deficient cancer-related anemia in the LC-06-JCK model. We demonstrated that inhibition of the IL-6 signaling pathway by MR16-1 treatment resulted in significant recovery of iron-deficiency anemia and alleviation of cancer-related symptoms. These results indicate that IL-6 signaling might be one possible target pathway to treat cancer-related anemia disorders.

Vitamin D3 supplementation using an oral spray solution resolves deficiency but has no effect on VO2 max in Gaelic footballers: results from a randomised, double-blind, placebo-controlled trial

PURPOSE

Vitamin D inadequacy is a global health concern in athletes as well as the general population. Whilst the role of vitamin D in skeletal health is well defined, there remains uncertainty over whether vitamin D supplementation has an added benefit beyond bone health.

METHODS

This randomised placebo-controlled trial in healthy male and female Gaelic footballers (n = 42) investigated the effect of vitamin D₃ supplementation [3000 IU (75 µg) daily for 12 weeks, via an oral spray solution] on VO₂ max which was the primary outcome measure. Secondary outcomes included skeletal muscle and lung function.

RESULTS

Supplementation significantly increased total 25-hydroxyvitamin D concentrations compared to the placebo group (mean ± SD change from baseline, 36.31 ± 32.34 vs. 6.11 ± 23.93 nmol/L, respectively; P = 0.006). At baseline, 50 and 22 % of footballers presented with vitamin D insufficiency (31-49 nmol/L) and deficiency (<30 nmol/L), respectively. Total 25-hydroxyvitamin D concentration did not significantly correlate with any measure of physical performance. Analysis of covariance (ANCOVA) models demonstrated that vitamin D supplementation over 12 weeks had no significant effect on VO₂ max (P = 0.375), vertical jump height (P = 0.797), left and right handgrip strength (P = 0.146 and P = 0.266, respectively), forced vital capacity (P = 0.573) or forced expiratory volume at 1 s (P = 0.665), after adjusting for confounders. The high prevalence of vitamin D inadequacy observed in this cohort of collegiate Gaelic footballers supports the need for vitamin D supplementation during wintertime to avoid being at risk of poor bone health.

CONCLUSIONS

Twelve-week daily supplementation with 3000 IU (75 µg) vitamin D₃ successfully resolved deficiency but did not have any significant effect on VO₂ max, skeletal muscle or lung function.

Evaluation of iron and zinc levels in recurrent tonsillitis and tonsillar hypertrophy

OBJECTIVES

The aim of this study is to look into the roles of iron and zinc metals in etiopathogenesis of recurrent tonsillitis and tonsillar hypertrophy by evaluating the levels of iron and zinc elements in the palatine tonsillar tissue.

METHODS

In total, 40 patients who underwent a tonsillectomy to treat recurrent tonsillitis and tonsillar hypertrophy were included in the study. Patients were classified into two groups, recurrent tonsillitis and tonsillar hypertrophy, determined by the results of clinical and histopathological examination. The levels of iron and zinc elements were determined for each tonsillar tissue sample.

RESULTS

There was a significant difference in the iron and zinc concentrations (p<0.001) between the tonsillar hypertrophy and recurrent tonsillitis groups. The levels of iron and zinc were significantly lower in the recurrent tonsillitis group.

CONCLUSIONS

This study suggests that low tissue concentrations of iron and zinc may lead to recurrent tonsillitis.

Quantitative analysis of dietary iron utilization for erythropoiesis in response to body iron status

Erythropoiesis requires large amounts of iron for hemoglobin synthesis. There are two sources of iron for erythropoiesis, dietary and stored iron; however, their relative contributions to erythropoiesis remain unknown. In this study, we used the stable iron isotope (57)Fe to quantify synthesis of hemoglobin derived from dietary iron. Using this method, we investigated the activities of dietary iron absorption and the utilization of dietary iron for erythropoiesis in responses to stimulated erythropoiesis and to interventions to alter body iron status. Under iron-loaded conditions, the activity of dietary iron absorption was clearly lowered in response to up-regulation of hepcidin, although the estimated activity of iron release from stored iron was not compared with that under control conditions. This result was supported by the observation that two duodenal iron transporters, divalent metal transporter 1 (DMT1) and ferroportin, were downregulated by iron loading, although the levels of expression of ferroportin in iron storage tissues were not changed by iron loading under erythropoietic stimulation by epoetin-β pegol (C.E.R.A., a long-acting erythropoiesis-stimulating agent). These results indicate that the dietary iron absorption system is more sensitive to body iron status than are reticuloendothelial iron- release mechanisms. Our data indicated that there could be a regulatory mechanism favoring use of stored iron over dietary iron under iron-loaded conditions.

A review of iron studies in overweight and obese children and adolescents: a double burden in the young?

INTRODUCTION

The connection between iron and excessive adiposity has received much research interest. Although children and adolescents have unique developmental phases and nutritional demands, to date, reviews of iron in the overweight (OW) and obese (OB) have combined studies of children and adults or have focussed on adults.

PURPOSE

The aim of this review was to critically evaluate studies of the relationship between iron and OW and obesity in children and adolescents, with emphasis on iron status, oral iron response, dietary intake and systemic inflammatory markers.

METHODS

A PubMed search was conducted to identify relevant articles published up to December 2015. Combinations of the following keywords were used: iron, OW, OB, children, adolescents, diet, hepcidin, inflammation, fortification, supplementation, weight loss, trace elements, obesity, iron deficiency (ID), minerals.

RESULTS AND CONCLUSION

A higher prevalence of ID, or risk of ID, among OW and OB children and adolescents has been consistently observed. Chronic inflammation caused by excessive adiposity offers a plausible explanation for this finding, rather than dietary factors. However, future studies must employ screening for the presence of both acute and chronic infections and inflammatory conditions and report other factors such as pubertal status. Intervention studies, although few, indicate that OW and OB children and adolescents have reduced response to oral iron. Further trials are needed to explore the connection between body fat mass, inflammatory proteins and iron absorption, together with the effect of weight loss on iron status in iron-deficient OW and OB children and adolescents.

Roxadustat (FG-4592) Versus Epoetin Alfa for Anemia in Patients Receiving Maintenance Hemodialysis: A Phase 2, Randomized, 6- to 19-Week, Open-Label, Active-Comparator, Dose-Ranging, Safety and Exploratory Efficacy Study

BACKGROUND

Roxadustat (FG-4592) is an oral hypoxia-inducible factor prolyl-hydroxylase inhibitor that promotes erythropoiesis through increasing endogenous erythropoietin, improving iron regulation, and reducing hepcidin.

STUDY DESIGN

Phase 2, randomized (3:1), open-label, active-comparator, safety and efficacy study.

SETTING & PARTICIPANTS

Patients with stable end-stage renal disease treated with hemodialysis who previously had hemoglobin (Hb) levels maintained with epoetin alfa.

INTERVENTION

Part 1: 6-week dose-ranging study in 54 individuals of thrice-weekly oral roxadustat doses versus continuation of intravenous epoetin alfa. Part 2: 19-week treatment in 90 individuals in 6 cohorts with various starting doses and adjustment rules (1.0-2.0mg/kg or tiered weight based) in individuals with a range of epoetin alfa responsiveness. Intravenous iron was prohibited.

OUTCOMES

Primary end point was Hb level response, defined as end-of-treatment Hb level change (ΔHb) of -0.5g/dL or greater from baseline (part 1) and as mean Hb level ≥ 11.0g/dL during the last 4 treatment weeks (part 2).

MEASUREMENTS

Hepcidin, iron parameters, cholesterol, and plasma erythropoietin (the latter in a subset).

RESULTS

Baseline epoetin alfa doses were 138.3±51.3 (SD) and 136.3±47.7U/kg/wk in part 1 and 152.8±80.6 and 173.4±83.7U/kg/wk in part 2, in individuals randomly assigned to roxadustat and epoetin alfa, respectively. Hb level responder rates in part 1 were 79% in pooled roxadustat 1.5 to 2.0mg/kg compared to 33% in the epoetin alfa control arm (P=0.03). Hepcidin level reduction was greater at roxadustat 2.0mg/kg versus epoetin alfa (P<0.05). In part 2, the average roxadustat dose requirement for Hb level maintenance was ∼1.7mg/kg. The least-squares-mean ΔHb in roxadustat-treated individuals was comparable to that in epoetin alfa-treated individuals (about -0.5g/dL) and the least-squares-mean difference in ΔHb between both treatment arms was -0.03 (95% CI, -0.39 to 0.33) g/dL (mixed effect model-repeated measure). Roxadustat significantly reduced mean total cholesterol levels, not observed with epoetin alfa. No safety concerns were raised.

LIMITATIONS

Short treatment duration and small sample size.

CONCLUSIONS

In this phase 2 study of anemia therapy in patients with end-stage renal disease on maintenance hemodialysis therapy, roxadustat was well tolerated and effectively maintained Hb levels.

Long-term risk of type 2 diabetes in relation to habitual iron intake in women with a history of gestational diabetes: a prospective cohort study

BACKGROUND

An iron overload may induce pancreatic islet damage and increase risk of diabetes. Women with a history of gestational diabetes mellitus (GDM) are at high risk of developing type 2 diabetes mellitus (T2DM) after pregnancy.

OBJECTIVE

We aimed to examine the association of habitual iron intake with long-term risk of T2DM in this high-risk population.

DESIGN

We included 3976 women with a history of GDM from the Nurses' Health Study II cohort as part of the ongoing Diabetes & Women's Health Study. The women were followed up through 2009. Iron intake was assessed with the use of a validated food-frequency questionnaire in 1991 and every 4 y thereafter. We used Cox proportional hazards models to estimate HRs and 95% CIs.

RESULTS

We documented 641 incident T2DM cases during 57,683 person-years of observation. Adjusted HRs for T2DM for the highest quartile compared with the lowest quartile were 1.64 (95% CI: 1.20, 2.25; P-trend = 0.02) for total iron intake and 1.80 (95% CI: 1.18, 2.74; P-trend = 0.005) for dietary heme iron intake. In addition, women who consumed ≥30.0 mg supplemental Fe/d, compared with nonusers, had an adjusted HR of 1.83 (95% CI: 1.25, 2.70; P-trend = 0.002).

CONCLUSION

In women with a history of GDM, greater intakes of total iron, dietary heme iron, and supplemental iron were associated with higher risk of T2DM.

Reduction of a marker of oxidative stress with enhancement of iron utilization by erythropoiesis activation following epoetin beta pegol administration in iron-loaded db/db mice

Iron, an essential element for various biological processes, can induce oxidative stress. We hypothesized that iron utilization for erythropoiesis, stimulated by epoetin beta pegol (C.E.R.A.), a long-acting erythropoiesis-stimulating agent, contributes to the reduction of iron-induced oxidative stress. We first investigated the sensitivity of several biomarkers to detect oxidative stress in mice by altering the amount of total body iron; we then investigated whether C.E.R.A. ameliorated oxidative stress through enhanced iron utilization. We treated db/db mice with intravenous iron-dextran and evaluated several biomarkers of iron-induced oxidative stress. In mice loaded with 5 mg/head iron, hepatic iron content was elevated and the oxidative stress marker d-ROMs (serum derivatives of reactive oxygen metabolites) was increased, whereas urinary 8-hydroxy-2'-deoxyguanosine and serum malondialdehyde were not, indicating that d-ROMs is a sensitive marker of iron-induced oxidative stress. To investigate whether C.E.R.A. ameliorated oxidative stress, db/db mice were intravenously administered iron-dextran or dextran only, followed by C.E.R.A. Hemoglobin level increased, while hepatic iron content decreased after C.E.R.A.

TREATMENT

Serum d-ROMs decreased after C.E.R.A. treatment in the iron-dextran-treated group. Our results suggest that C.E.R.A. promotes iron utilization for erythropoiesis through mobilization of hepatic iron storage, leading to a decrease in serum oxidative stress markers in iron-loaded db/db mice.

Blood Lead and Other Metal Biomarkers as Risk Factors for Cardiovascular Disease Mortality

Analyses of the Third National Health and Nutrition Examination Survey (NHANES III) in 1988 to 1994 found an association of increasing blood lead levels < 10 μg/dL with a higher risk of cardiovascular disease (CVD) mortality. The potential need to correct blood lead for hematocrit/hemoglobin and adjust for biomarkers for other metals, for example, cadmium and iron, had not been addressed in the previous NHANES III-based studies on blood lead-CVD mortality association. We analyzed 1999 to 2010 NHANES data for 18,602 participants who had a blood lead measurement, were ≥ 40 years of age at the baseline examination and were followed for mortality through 2011. We calculated the relative risk for CVD mortality as a function of hemoglobin- or hematocrit-corrected log-transformed blood lead through Cox proportional hazard regression analysis with adjustment for serum iron, blood cadmium, serum C-reactive protein, serum calcium, smoking, alcohol intake, race/Hispanic origin, and sex. The adjusted relative risk for CVD mortality was 1.44 (95% confidence interval = 1.05, 1.98) per 10-fold increase in hematocrit-corrected blood lead with little evidence of nonlinearity. Similar results were obtained with hemoglobin-corrected blood lead. Not correcting blood lead for hematocrit/hemoglobin resulted in underestimation of the lead-CVD mortality association while not adjusting for iron status and blood cadmium resulted in overestimation of the lead-CVD mortality association. In a nationally representative sample of U.S. adults, log-transformed blood lead was linearly associated with increased CVD mortality. Correcting blood lead for hematocrit/hemoglobin and adjustments for some biomarkers affected the association.

Prevalence of anemia and associations between neonatal iron status, hepcidin, and maternal iron status among neonates born to pregnant adolescents

BACKGROUND

Little is known about anemia and iron status in US newborns because screening for anemia is typically not undertaken until 1 y of age. This study was undertaken to characterize and identify determinants of iron status in newborns born to pregnant adolescents.

METHODS

Pregnant adolescents (≤ 18 y, n = 193) were followed from ≥ 12 wk gestation until delivery. Hemoglobin, ferritin, soluble transferrin receptor, serum iron, hepcidin, erythropoietin (EPO), IL-6, and C-reactive protein were assessed in maternal and cord blood.

RESULTS

At birth, 21% of the neonates were anemic (Hb < 13.0 g/dl) and 25% had low iron stores (ferritin < 76 µg/l). Cord serum ferritin concentrations were not significantly associated with gestational age (GA) at birth across the range of 37-42 wk. Neonates born to mothers with ferritin < 12 µg/l had significantly lower ferritin (P = 0.003) compared to their counterparts. Hepcidin and IL-6 were significantly (P < 0.05) higher in neonates born to mothers with longer durations of active labor.

CONCLUSION

Given the importance of the iron stores at birth on maintenance of iron homeostasis over early infancy, additional screening of iron status at birth is warranted among those born to this high risk obstetric population.

Dietary iron concentration influences serum concentrations of manganese in rats consuming organic or inorganic sources of manganese

To determine the effects of dietary Fe concentration on Mn bioavailability in rats fed inorganic or organic Mn sources, fifty-four 22-d-old male rats were randomly assigned and fed a basal diet (2·63 mg Fe/kg) supplemented with 0 (low Fe (L-Fe)), 35 (adequate Fe (A-Fe)) or 175 (high Fe (H-Fe)) mg Fe/kg with 10 mg Mn/kg from MnSO4 or Mn–lysine chelate (MnLys). Tissues were harvested after 21 d of feeding. Serum Mn was greater (P<0·05) in MnLys rats than in MnSO4 rats, and in L-Fe rats than in A-Fe or H-Fe rats. Duodenal divalent metal transporter-1 (DMT1) mRNA was lower (P<0·05) in H-Fe rats than in A-Fe rats for the MnSO4 treatment; however, no significant difference was observed between them for MnLys. Liver DMT1 mRNA abundance was greater (P<0·05) in MnSO4 than in the MnLys group for H-Fe rats. The DMT1 protein in duodenum and liver and ferroportin 1 (FPN1) protein in liver was greater (P<0·05) in the MnSO4 group than in the MnLys group, and in L-Fe rats than in H-Fe rats. Duodenal FPN1 protein was greater (P<0·05) in L-Fe rats than in A-Fe rats for the MnLys treatment, but it was not different between them for the MnSO4 treatment. Results suggest that MnLys increased serum Mn concentration as compared with MnSO4 in rats irrespective of dietary Fe concentration, which was not because of the difference in DMT1 and FPN1 expression in the intestine and liver.

EGCG Protects against 6-OHDA-Induced Neurotoxicity in a Cell Culture Model

Background. Parkinson's disease (PD) is a progressive neurodegenerative disease that causes severe brain dopamine depletion. Disruption of iron metabolism may be involved in the PD progression. Objective. To test the protective effect of (-)-epigallocatechin-3-gallate (EGCG) against 6-hydroxydopamine- (6-OHDA-) induced neurotoxicity by regulating iron metabolism in N27 cells. Methods. Protection by EGCG in N27 cells was assessed by SYTOX green assay, MTT, and caspase-3 activity. Iron regulatory gene and protein expression were measured by RT-PCR and Western blotting. Intracellular iron uptake was measured using (55)Fe. The EGCG protection was further tested in primary mesencephalic dopaminergic neurons by immunocytochemistry. Results. EGCG protected against 6-OHDA-induced cell toxicity. 6-OHDA treatment significantly (p < 0.05) increased divalent metal transporter-1 (DMT1) and hepcidin and decreased ferroportin 1 (Fpn1) level, whereas pretreatment with EGCG counteracted the effects. The increased (55)Fe (by 96%, p < 0.01) cell uptake confirmed the iron burden by 6-OHDA and was reduced by EGCG by 27% (p < 0.05), supporting the DMT1 results. Pretreatment with EGCG and 6-OHDA significantly increased (p < 0.0001) TH(+) cell count (~3-fold) and neurite length (~12-fold) compared to 6-OHDA alone in primary mesencephalic neurons. Conclusions. Pretreatment with EGCG protected against 6-OHDA-induced neurotoxicity by regulating genes and proteins involved in brain iron homeostasis, especially modulating hepcidin levels.

Iron metabolism and regulation by neutrophil gelatinase-associated lipocalin in cardiomyopathy

Neutrophil gelatinase-associated lipocalin (NGAL) has recently become established as an important contributor to the pathophysiology of cardiovascular disease. Accordingly, it is now viewed as an attractive candidate as a biomarker for various disease states, and in particular has recently become regarded as one of the best diagnostic biomarkers available for acute kidney injury. Nevertheless, the precise physiological effects of NGAL on the heart and the significance of their alterations during the development of heart failure are only now beginning to be characterized. Furthermore, the mechanisms via which NGAL mediates its effects are unclear because there is no conventional receptor signalling pathway. Instead, previous work suggests that regulation of iron metabolism could represent an important mechanism of NGAL action, with wide-ranging consequences spanning metabolic and cardiovascular diseases to host defence against bacterial infection. In the present review, we summarize rapidly emerging evidence for the role of NGAL in regulating heart failure. In particular, we focus on iron transport as a mechanism of NGAL action and discuss this in the context of the existing strong associations between iron overload and iron deficiency with cardiomyopathy.

Iron Metabolism Dysregulation and Cognitive Dysfunction in Pediatric Obesity: Is There a Connection?

Obesity and iron deficiency (ID) are two of the most common nutritional disorders in the world. In children both conditions deserve particular attention. Several studies revealed an association between obesity and iron deficiency in children and, in some cases, a reduced response to oral supplementation. The connecting mechanism, however, is not completely known. This review is focused on: (1) iron deficiency in obese children and the role of hepcidin in the connection between body fat and poor iron status; (2) iron status and consequences on health, in particular on cognitive function; (3) cognitive function and obesity; (4) suggestion of a possible link between cognitive dysfunction and ID in pediatric obesity; and implications for therapy and future research.

CD1 Mouse Retina Is Shielded From Iron Overload Caused by a High Iron Diet

PURPOSE

High RPE iron levels have been associated with age-related macular degeneration. Mutation of the ferroxidase ceruloplasmin leads to RPE iron accumulation and degeneration in patients with aceruloplasminemia; mice lacking ceruloplasmin and its homolog hephaestin have a similar RPE degeneration. To determine whether a high iron diet (HID) could cause RPE iron accumulation, possibly contributing to RPE oxidative stress in AMD, we tested the effect of dietary iron on mouse RPE iron.

METHODS

Male CD1 strain mice were fed either a standard iron diet (SID) or the same diet with extra iron added (HID) for either 3 months or 10 months. Mice were analyzed with immunofluorescence and Perls' histochemical iron stain to assess iron levels. Levels of ferritin, transferrin receptor, and oxidative stress gene mRNAs were measured by quantitative PCR (qPCR) in neural retina (NR) and isolated RPE. Morphology was assessed in plastic sections.

RESULTS

Ferritin immunoreactivity demonstrated a modest increase in the RPE in 10-month HID mice. Analysis by qPCR showed changes in mRNA levels of iron-responsive genes, indicating moderately increased iron in the RPE of 10-month HID mice. However, even by age 18 months, there was no Perls' signal in the retina or RPE and no retinal degeneration.

CONCLUSIONS

These findings indicate that iron absorbed from the diet can modestly increase the level of iron deposition in the wild-type mouse RPE without causing RPE or retinal degeneration. This suggests regulation of retinal iron uptake at the blood-retinal barriers.

Iron-refractory iron deficiency anemia

Iron is essential for life because it is indispensable for several biological reactions, such as oxygen transport, DNA synthesis, and cell proliferation. Over the past few years, our understanding of iron metabolism and its regulation has changed dramatically. New disorders of iron metabolism have emerged, and the role of iron as a cofactor in other disorders has begun to be recognized. The study of genetic conditions such as hemochromatosis and iron-refractory iron deficiency anemia (IRIDA) has provided crucial insights into the molecular mechanisms controlling iron homeostasis. In the future, these advances may be exploited to improve treatment of both genetic and acquired iron disorders. IRIDA is caused by mutations in TMPRSS6, the gene encoding matriptase-2, which downregulates hepcidin expression under conditions of iron deficiency. The typical features of this disorder are hypochromic, microcytic anemia with a very low mean corpuscular volume of erythrocytes, low transferrin saturation, no (or inadequate) response to oral iron, and only a partial response to parenteral iron. In contrast to classic iron deficiency anemia, serum ferritin levels are usually low-normal, and serum or urinary hepcidin levels are inappropriately high for the degree of anemia. Although the number of cases reported thus far in the literature does not exceed 100, this disorder is considered the most common of the “atypical” microcytic anemias. The aim of this review is to share the current knowledge on IRIDA and increase awareness in this field.

Phylogenetic and Ontogenetic View of Erythroblastic Islands

Erythroblastic islands are a hallmark of mammalian erythropoiesis consisting of a central macrophage surrounded by and interacting closely with the maturing erythroblasts. The macrophages are thought to serve many functions such as supporting erythroblast proliferation, supplying iron for hemoglobin, promoting enucleation, and clearing the nuclear debris; moreover, inhibition of erythroblastic island formation is often detrimental to erythropoiesis. There is still much not understood about the role that macrophages and microenvironment play in erythropoiesis and insights may be gleaned from a comparative analysis with erythropoietic niches in nonmammalian vertebrates which, unlike mammals, have erythrocytes that retain their nucleus. The phylogenetic development of erythroblastic islands in mammals in which the erythrocytes are anucleate underlines the importance of the macrophage in erythroblast enucleation.

An important role of the hepcidin-ferroportin signaling in affecting tumor growth and metastasis

Epidemiological and experimental studies have suggested that deregulated hepcidin-ferroportin (FPN) signaling is associated with the increased risk of cancers. However, the effects of deregulated hepcidin-FPN signaling on tumor behaviors such as metastasis and epithelial to mesenchymal transition (EMT) have not been closely investigated. In this study, LL/2 cancer cells were found to exhibit an impaired propensity to home into lungs, and a reduced ability to develop tumors was also demonstrated in lungs of Hamp1(-/-) mice. Moreover, hepatic hepcidin deficiency was found to considerably favor tumor-free survival in Hamp1(-/-) mice, compared with wild-type mice. These data thus underscored a contributive role of hepatic hepcidin in promoting lung cancer cell homing and fostering tumor progression. To explore the role of FPN in regulating tumor progression, we genetically engineered 4T1 cells with FPN over-expression upon induction by doxycycline. With this cell line, it was discovered that increased FPN expression reduced cell division and colony formation in vitro, without eliciting significant cell death. Analogously, FPN over-expression impeded tumor growth and metastasis to lung and liver in mice. At the molecular level, FPN over-expression was identified to undermine DNA synthesis and cell cycle progression. Importantly, FPN over-expression inhibited EMT, as reflected by the significant decrease of representative EMT markers, such as Snail1, Twist1, ZEB2, and vimentin. Additionally, there was also a reduction of lactate production in cells upon induction of FPN over-expression. Together, our results highlighted a crucial role of the hepcidin-FPN signaling in modulating tumor growth and metastasis, providing new evidence to understand the contribution of this signaling in cancers.

Randomized placebo-controlled dose-ranging and pharmacodynamics study of roxadustat (FG-4592) to treat anemia in nondialysis-dependent chronic kidney disease (NDD-CKD) patients

Background

Roxadustat (FG-4592) is an oral hypoxia-inducible factor prolyl hydroxylase inhibitor that stimulates erythropoiesis. This Phase 2a study tested efficacy (Hb response) and safety of roxadustat in anemic nondialysis-dependent chronic kidney disease (NDD-CKD) subjects.

Methods

NDD-CKD subjects with hemoglobin (Hb) ≤11.0 g/dL were sequentially enrolled into four dose cohorts and randomized to roxadustat or placebo two times weekly (BIW) or three times weekly (TIW) for 4 weeks, in an approximate roxadustat:placebo ratio of 3:1. Efficacy was assessed by (i) mean Hb change (ΔHb) from baseline (BL) and (ii) proportion of Hb responders (ΔHb ≥ 1.0 g/dL). Pharmacodynamic evaluation was performed in a subset of subjects. Safety was evaluated by adverse event frequency/severity.

Results

Of 116 subjects receiving treatment, 104 completed 4 weeks of dosing and 96 were evaluable for efficacy. BL characteristics for roxadustat and placebo groups were comparable. In roxadustat-treated subjects, Hb levels increased from BL in a dose-related manner in the 0.7, 1.0, 1.5 and 2.0 mg/kg groups. Maximum ΔHb within the first 6 weeks was significantly higher in the 1.5 and 2.0 mg/kg groups than in the placebo subjects. Hb responder rates were dose dependent and ranged from 30% in the 0.7 mg/kg BIW group to 100% in the 2.0 mg/kg BIW and TIW groups versus 13% in placebo.

Conclusions

Roxadustat transiently and moderately increased endogenous erythropoietin and reduced hepcidin. Adverse events were similar in the roxadustat and placebo groups. Roxadustat produced dose-dependent increases in blood Hb among anemic NDD-CKD patients in a placebo-controlled trial.

Clinical Trials Registration

Clintrials.gov #NCT00761657.

Lipopolysaccharides upregulate hepcidin in neuron via microglia and the IL-6/STAT3 signaling pathway

Neuroinflammation is closely related to brain iron homeostasis. Our previous study demonstrated that lipopolysaccharides (LPS) can regulate expression of iron-regulatory peptide hepcidin; however, the mechanism is undefined. Here, we demonstrated that intracerebroventricular injection of LPS in rat brain upregulated hepcidin and downregulated ferroportin 1 in the cortex and substantia nigra. LPS increased hepcidin expression in neurons only when they were co-cultured with BV-2 microglia, and the upregulation was suppressed by IL-6 neutralizing antibody in vitro. In addition, IL-6 but not IL-1α, IL-1β, or tumor necrosis factor-alpha increased hepcidin expression and signal transducer and activator of transcription 3 (STAT3) phosphorylation in cortical neurons and MES23.5 dopaminergic neurons. These effects were blocked by the STAT3 inhibitor, stattic. Our results show that neurons are the major source of increased hepcidin expression in response to LPS challenge but microglia play a key mediator role by releasing IL-6 and recruiting the STAT3 pathway. We conclude that LPS upregulates hepcidin expression in neurons via microglia and the IL-6/STAT3 signaling pathway.

Maternal intestinal HIF-2α is necessary for sensing iron demands of lactation in mice

The mechanisms that are essential for the maintenance of nutrient status in breast milk are unclear. Our data demonstrate that the intestine via hypoxia-inducible factor (HIF)-2α is an essential regulatory mechanism for maintaining the quality of breast milk. During lactation, intestinal HIF-2α is highly increased, leading to an adaptive induction of apical and basolateral iron transport genes. Disruption of intestinal HIF-2α (but not HIF-1α) or the downstream target gene divalent metal transporter (DMT)-1 in lactating mothers did not alter systemic iron homeostasis in the mothers, but led to anemia, decreased growth, and truncal alopecia in pups which was restored following weaning. Moreover, pups born from mothers with a disruption of intestinal HIF-2α led to long-term cognitive defects. Cross-fostering experiments and micronutrient profiling of breast milk demonstrated that the defects observed were due to decreased maternal iron delivery via milk. Increasing intestinal iron absorption by activation of HIF-2α or parenteral administration of iron-dextran in HIF-2α knockout mothers ameliorated anemia and restored neonatal development and adult cognitive functions. The present work details the importance of breast milk iron in neonatal development and uncovers an unexpected molecular mechanism for the regulation of nutritional status of breast milk through intestinal HIF-2α.

Constitutive activities of estrogen-related receptors: Transcriptional regulation of metabolism by the ERR pathways in health and disease

The estrogen-related receptors (ERRs) comprise a small group of orphan nuclear receptor transcription factors. The ERRα and ERRγ isoforms play a central role in the regulation of metabolic genes and cellular energy metabolism. Although less is known about ERRβ, recent studies have revealed the importance of this isoform in the maintenance of embryonic stem cell pluripotency. Thus, ERRs are essential to many biological processes. The development of several ERR knockout and overexpression models and the application of advanced functional genomics have allowed rapid advancement of our understanding of the physiology regulated by ERR pathways. Moreover, it has enabled us to begin to delineate the distinct programs regulated by ERRα and ERRγ that have overlapping effects on metabolism and growth. The current review primarily focuses on the physiologic roles of ERR isoforms related to their metabolic regulation; therefore, the ERRα and ERRγ are discussed in the greatest detail. We emphasize findings from gain- and loss-of-function models developed to characterize ERR control of skeletal muscle, heart and musculoskeletal physiology. These models have revealed that coordinating metabolic capacity with energy demand is essential for seemingly disparate processes such as muscle differentiation and hypertrophy, innate immune function, thermogenesis, and bone remodeling. Furthermore, the models have revealed that ERRα- and ERRγ-deficiency in mice accelerates progression of pathologic processes and implicates ERRs as etiologic factors in disease. We highlight the human diseases in which ERRs and their downstream metabolic pathways are perturbed, including heart failure and diabetes. While no natural ligand has been identified for any of the ERR isoforms, the potential for using synthetic small molecules to modulate their activity has been demonstrated. Based on our current understanding of their transcriptional mechanisms and physiologic relevance, the ERRs have emerged as potential therapeutic targets for treatment of osteoporosis, muscle atrophy, insulin resistance and heart failure in humans.

Decreased expression of ferroportin in prostate cancer

The present study examined the expression levels of ferroportin, a transmembrane protein that transports iron from the inside of a cell to the outside, in the prostate cancer PC3, DU145 and LNCAP cell lines, in the normal prostate RWPE2 cell line, and in tissue samples from different differentiation stages of prostatic carcinoma and prostatic hyperplasia. The study also investigated the role of ferroportin protein expression in the diagnosis and prognosis of prostate cancer. Reverse transcription-quantitative polymerase chain reaction and western blot analysis were employed to measure the mRNA and protein expression levels of ferroportin in the PC3, DU145, LNCAP and RWPE2 cells. Immunohistochemistry was used to determine ferroportin protein expression in the prostate cancer and prostatic hyperplasia tissues. Compared with the normal prostate RWPE2 cells, ferroportin protein expression was significantly lower in the prostate cancer PC3, DU145 and LNCAP cells (P<0.05). Compared with the prostatic hyperplasia tissues, ferroportin protein expression was significantly reduced in the prostate cancer tissues (P<0.05). Overall, the expression levels of ferroportin in the prostate cancer tissues were lower than those in the normal prostate tissues, which may provide valuable clinical information for the diagnosis and prediction of disease progression in prostate cancer, and may indicate a potential therapeutic target for treating prostate cancer by regulating iron metabolism.

Iron status in obesity: An independent association with metabolic parameters and effect of weight loss

BACKGROUND AND AIMS

Growing evidence has shown that ferritin concentrations are associated with obesity and insulin resistance, and with nonalcoholic fatty liver disease. However, it is unclear whether ferritin is simply an inflammatory marker, or it may directly contribute to the pathogenesis of obesity-related metabolic alterations. The aim of our study was to investigate the independent associations of ferritin levels with metabolic parameters in overweight/obese subjects before and after hypocaloric diet-induced weight changes.

METHODS AND RESULTS

A sample study of 48 premenopausal, 39 postmenopausal women and 50 men was retrospectively analyzed. Clinical, bioimpedentiometry and biochemical data from baseline evaluations and after 3, 6 and 12 months of hypocaloric diet were collected. In the whole sample study, the baseline values of ferritin concentrations were positively correlated with body mass index (BMI) (r = 0.21, p < 0.05) and mass body fat (MBF) (r = 0.26, p < 0.05), whereas the serum iron level was negatively correlated with MBF (r = -0.29, p < 0.05). In premenopausal women, BMI-adjusted ferritin concentrations were negatively associated with high-density lipoprotein-cholesterol and positively related with triglycerides and aspartate aminotransferase. Moreover, the quantitative ferritin reduction at 12 months was positively associated with the relative reduction of BMI (r = 0.34, p < 0.05). Finally, the association between changes of alanine aminotransferase and ferritin levels at 12 months from baseline turned out to be independent of respective BMI changes (β = 0.31, p < 0.05).

CONCLUSION

In obesity, ferritin, putatively entailing increased iron storage, is independently associated with lipid derangements and transaminase levels, and the association with the latter persists after weight changes.

The effect of alcohol and hydrogen peroxide on liver hepcidin gene expression in mice lacking antioxidant enzymes, glutathione peroxidase-1 or catalase

This study investigates the regulation of hepcidin, the key iron-regulatory molecule, by alcohol and hydrogen peroxide (H2O2) in glutathione peroxidase-1 (gpx-1(-/-)) and catalase (catalase(-/-)) knockout mice. For alcohol studies, 10% ethanol was administered in the drinking water for 7 days. Gpx-1(-/-) displayed significantly higher hepatic H2O2 levels than catalase(-/-) compared to wild-type mice, as measured by 2'-7'-dichlorodihydrofluorescein diacetate (DCFH-DA). The basal level of liver hepcidin expression was attenuated in gpx-1(-/-) mice. Alcohol increased H2O2 production in catalase(-/-) and wild-type, but not gpx-1(-/-), mice. Hepcidin expression was inhibited in alcohol-fed catalase(-/-) and wild-type mice. In contrast, alcohol elevated hepcidin expression in gpx-1(-/-) mice. Gpx-1(-/-) mice also displayed higher level of basal liver CHOP protein expression than catalase(-/-) mice. Alcohol induced CHOP and to a lesser extent GRP78/BiP expression, but not XBP1 splicing or binding of CREBH to hepcidin gene promoter, in gpx-1(-/-) mice. The up-regulation of hepatic ATF4 mRNA levels, which was observed in gpx-1(-/-) mice, was attenuated by alcohol. In conclusion, our findings strongly suggest that H2O2 inhibits hepcidin expression in vivo. Synergistic induction of CHOP by alcohol and H2O2, in the absence of gpx-1, stimulates liver hepcidin gene expression by ER stress independent of CREBH.

Does moderate iron deficiency protect against childhood illness? A test of the optimal iron hypothesis in Tanzania

OBJECTIVES

To test the hypothesis that moderate iron deficiency among children is associated with lower likelihood of infection.

MATERIALS AND METHODS

We use data from a population representative cross sectional study of 1164 Tanzanian children aged 6-59 months from the Tanzania Demographic and Health Survey. Respondents' iron levels were assessed through serum transferrin receptor (sTfR) and anemia was assessed using hemoglobin. C-reactive protein (CRP) was used as a marker of infection.

RESULTS

Nearly 25% of the children were categorized as normal (iron replete, non-anemic); 45% were IDE (low iron, non-anemic), 24% were classified as IDA (low iron, anemic), and 69 children (5.9%) were anemic but had no evidence of iron deficiency. IDE was not associated with a lower likelihood of elevated CRP compared to iron replete, non-anemic children; 45% of normal children had elevated CRP compared to 51% of IDE children (P = 0.10). IDA, by contrast, was associated with a higher likelihood of elevated CRP (68%, P < 0.001). These results were unchanged when child, maternal, and household controls were added to a logistic regression model.

DISCUSSION

Our results do not support the optimal iron hypothesis as conventionally formulated. The fact that we did not find an effect where some other studies have may be due to differences in study design, sample (e.g., age), or the baseline pathogenic ecology. Alternatively, it may be more fruitful to investigate iron regulation as an allostatic system that responds to infections adaptively, rather than to expect an optimal pre-infection value.

Decreased ferroportin promotes myeloma cell growth and osteoclast differentiation

Iron homeostasis is disrupted in multiple myeloma, a difficult-to-cure plasma cell malignancy with lytic bone lesions. Here, we systematically analyzed iron gene expression signature and demonstrated that mRNA expression of iron exporter ferroportin (FPN1) is significantly downregulated in myeloma cells and correlates negatively with clinic outcome. Restoring expression of FPN1 reduces intracellular liable iron pool, inhibits STAT3-MCL-1 signaling, and suppresses myeloma cells growth. Furthermore, we demonstrated that mRNA of FPN1 is also downregulated at the initial stages of osteoclast differentiation and suppresses myeloma cell-induced osteoclast differentiation through regulating iron regulator TFRC, NF-κB, and JNK pathways. Altogether, we demonstrated that downregulation of FPN1 plays critical roles in promoting myeloma cell growth and bone resorption in multiple myeloma.

The pathophysiology of transfusional iron overload

The pathophysiologic consequences of transfusional iron overload (TIO) as well as the benefits of iron chelation therapy are best described in thalassemia major, although TIO is increasingly seen in other clinical settings. These consequences broadly reflect the levels and distribution of excess storage iron in the heart, endocrine tissues, and liver. TIO also increases the risk of infection, due to increased availability of labile iron to microorganisms. The authors suggest that extrahepatic iron distribution, and hence toxicity, is influenced by balance between generation of nontransferrin-bound iron from red cell catabolism and the utilization of transferrin iron by the erythron.

Laboratory and genetic assessment of iron deficiency in blood donors

More than 9 million individuals donate blood annually in the United States. Between 200 and 250 mg of iron is removed with each whole blood donation, reflecting losses from the hemoglobin in red blood cells. Replenishment of iron stores takes many months, leading to a high rate of iron depletion. In an effort to better identify and prevent iron deficiency, blood collection centers are now considering various strategies to manage donor iron loss. This article highlights laboratory and genetic tests to assess the iron status of blood donors and their applicability as screening tests for blood donation.

The pathophysiology and consequences of red blood cell storage

Red cell transfusion therapy is a common treatment modality in contemporary medical practice. Although blood collection and administration is safer and more efficient than ever before, red cells undergo multiple metabolic and structural changes during storage that may compromise their functionality and viability following transfusion. The clinical relevance of these changes is a hotly debated topic that continues to be a matter of intense investigation. In the current review, we begin with an in-depth overview of the pathophysiological mechanisms underlying red cell storage, with a focus on altered metabolism, oxidative stress and red cell membrane damage. We proceed to review the current state of evidence on the clinical relevance and consequences of the red cell storage lesion, while discussing the strengths and limitations of clinical studies.

Serum hepcidin level correlates with hyperlipidemia status in patients following allograft renal transplantation

Hepcidin is synthesized and secreted by liver cells and has been reported as one of the hormone molecules that regulates iron homeostasis. To determine whether serum level of hepcidin can be used as a biomarker for the evaluation of chronic inflammatory status, iron level and renal function in patients following allograft renal transplantation, serum levels of hepcidin, interleukin (IL)-6, ferritin, serum iron, and renal functions were measured. Sixty patients were included in the current study and were further separated into groups with or without hyperlipidemia. We found that allogeneic kidney transplant recipients with hyperlipidemia have significantly increased serum levels of hepcidin, IL-6, and ferritin. The increased serum hepcidin is positively correlated with serum IL-6 and ferritin as analyzed by single-factor correlation analysis. Multivariant correlation analysis in all specimens further demonstrated that serum hepcidin negatively correlated with glomerular filtration rate, and positively correlated with serum total cholesterol, triglycerides, serum ferritin, and IL-6. Our study demonstrated that serum level of hepcidin after allogeneic kidney transplantation not only reflects the status of chronic inflammation but can also indicate changes in renal function. Thus, hepcidin has the potential to be used as a promising marker for the detection and monitoring of the status of chronic inflammation, hyperlipidemia, and renal function in patients following allograft renal transplantation.

Signatures of resistance to Lepeophtheirus salmonis include a TH2-type response at the louse-salmon interface

Disease outbreaks with the salmon louse Lepeophtheirus salmonis cause significant economic losses in mariculture operations worldwide. Variable innate immune responses at the louse-attachment site contribute to differences in susceptibility among species such that members of Salmo spp. are more susceptible to infection than those of some Oncorhynchus spp. Relatively little is known about the mechanisms that contribute to disease resistance or susceptibility to L. salmonis in salmon. Here, we utilize histochemistry and transcriptomics in a comparative infection model with susceptible (Atlantic, sockeye) and resistant (coho) salmon. At least three cell populations (MHIIβ+, IL1β+, TNFα+) were activated in coho salmon skin during L. salmonis infection. Locally elevated expression of several pro-inflammatory mediators (e.g. IL1β, IL8, TNFα, COX2, C/EBPβ), and tissue repair enzymes (MMP9, MMP13) were detected in susceptible and resistant species. However, responses specific to coho salmon (e.g. IL4, IL6, TGFβ) or responses shared among susceptible salmon (e.g. SAP, TRF, Cath in Atlantic and sockeye salmon) provide evidence for species-specific pathways contributing to resistance or susceptibility, respectively. Our results confirm the importance of an early pro-inflammatory TH1-type pathway as an initial host response during infection with Pacific sea lice, and demonstrate subsequent regulatory TH2-type processes as candidate defense mechanisms in the skin of resistant coho salmon.

A Turn-Off Fluorescent Nanosensor for Iron in Aqueous Solution Based on Fluorescent Carbon Nanoparticles

The water-soluble fluorescent carbon nanomaterials with low toxicity and high biocompatibility are considered as promising materials for biomedical and sensor applications. Here, we report that a nanosensor system has been developed to simultaneously detect two valence states of iron ( Fe 2+ and/or Fe 3+) in aqueous solution based on fluorescent carbon nanoparticles (FCNs). The nanosensor has high selectivity and sensitivity with a limit of detection (LOD) of 5 μM, which is equivalent to 0.3 mg/L (5.36 μM) of iron in drinking water by United States Environment Protection Agency (US-EPA). Furthermore, a distinguishable color change of solution, from pale yellow to red-brown, can be observed as iron concentration reaching 40 μM, which provides way for fast, visible detection of irons.