Iron homeostasis in the neonate

Serum hepcidin and ferritin as markers of iron deficiency in premature infants born at less than 32 weeks of gestation: prospective observational study

BACKGROUND

Preterm infants born at less than 32 weeks of gestation are at higher risk of low total iron stores (iron deficiency). Serum ferritin is used as a valid total iron stores and iron deficiency biomarker, usually as a combination of ferritin and red blood cell counts.

METHODS

Serum hepcidin and ferritin values and red blood cell counts were obtained from 37 of 40 included premature infants born at less than 32 weeks of gestation at risk of iron deficiency. The first sample was obtained in the first week of life, and the second at transfer from the Neonatal intensive care unit to the maternity ward, when serum ferritin level below 25 µg/L has been defined as very low total iron stores (iron deficiency).

RESULTS

Ferritin median levels decreased from a median value of 152 µg/L at the first measurement to 54 µg/L at the second measurement. Hepcidin median levels also decreased from 30.1 µg/L to 2.1 µg/L. We found a positive and statistically significant correlation between levels of ferritin and hepcidin at both measurements (r=0.57; P<0.001 and r=0.72; P<0.001, respectively). Compared to serum hepcidin, ferritin at the first measurement has not statistically significant higher power in predicting children with iron deficiency before discharge from the hospital.

CONCLUSIONS

We found a correlation between ferritin and hepcidin levels. Nevertheless, hepcidin does not have a worse power in predicting children with iron deficiency compared to ferritin.

Effects of deferoxamine on intrinsic colistin resistance of Proteus mirabilis

Proteus mirabilis is a common pathogen, which is responsible for urinary tract infections. Iron is a critical element necessary for both humans and pathogens to maintain their biological functions, and iron limitation via chelator agents may be useful in the treatment of infections. The present study aimed to investigate the synergistic interactions between the iron chelator agent deferoxamine (DFO) and the antibacterial drug colistin. The minimum inhibitory concentration (MIC) values of DFO and colistin for P. mirabilis isolates were determined by broth microdilution. The checkerboard technique was used to examine the potential synergy between DFO and colistin. Furthermore, time-kill assays were used for the confirmation of synergy detected by the checkerboard assay, as well as for determining bacteriostatic and bactericidal interactions throughout a 24-h period. As expected, all P. mirabilis isolates were resistant to colistin. DFO did not inhibit P. mirabilis growth when used alone, even at very high doses (10 µg ml-1). Notably, when in combination with DFO, the MIC values of colistin were markedly reduced, and the checkerboard assay results showed synergy between colistin and DFO for all isolates. In addition, in time-kill assays, colistin + DFO exhibited synergistic activity against all strains at most time intervals and concentrations tested. Colistin + DFO showed bactericidal activity at colistin concentrations of 1xMIC and 2xMIC, although a degree of re-growth was observed in one of the strains at 12-24 h. These findings indicated that DFO has the potential for use as an adjunct to colistin through iron sequestration, thus providing synergistic activity to an antibiotic that would not normally be considered a treatment option against P. mirabilis. In vivo experiments in the future may provide useful information on the efficacy of DFO/colistin since these models effectively reflect physiological parameters.

Mechanism of iron on the intestinal epithelium development in suckling piglets

This study aimed to investigate the mechanism of iron on intestinal epithelium development of suckling piglets. Compared with newborn piglets, 7-day-old and 21-day-old piglets showed changes in the morphology of the jejunum, increased proliferation, differentiated epithelial cells, and expanded enteroids. Intestinal epithelium maturation markers and iron metabolism genes were significantly changed. These results suggest that lactation is a critical stage in intestinal epithelial development, accompanied by changes in iron metabolism. In addition, deferoxamine (DFO) treatment inhibited the activity of intestinal organoids at passage 4 (P4) of 0-day-old piglets, but no significant difference was observed in epithelial maturation markers at passage 1 (P1) and P4, and only argininosuccinate synthetase 1 (Ass1) and β-galactosidase (Gleb) were up-regulated at passage 7 (P7). These results in vitro show that iron deficiency may not directly affect intestinal epithelium development through intestinal stem cells (ISCs). The iron supplementation significantly down-regulated the mRNA expression of interleukin-22 receptor subunit alpha-2 (IL-22RA2) in the jejunum of piglets. Furthermore, the mRNA expression of IL-22 in 7-day-old piglets was significantly higher than that in 0-day-old piglets. Adult epithelial markers were significantly up-regulated in organoids treated with recombinant murine cytokine IL-22. Thus, IL-22 may play a key role in iron-affecting intestinal epithelium development.

The Role of Lactoferrin in Intestinal Health

The intestine represents one of the first barriers where microorganisms and environmental antigens come into tight contact with the host immune system. A healthy intestine is essential for the well-being of humans and animals. The period after birth is a very important phase of development, as the infant moves from a protected environment in the uterus to one with many of unknown antigens and pathogens. In that period, mother's milk plays an important role, as it contains an abundance of biologically active components. Among these components, the iron-binding glycoprotein, lactoferrin (LF), has demonstrated a variety of important benefits in infants and adults, including the promotion of intestinal health. This review article aims to provide a compilation of all the information related to LF and intestinal health, in infants and adults.

Anemia, Hepcidin, and Vitamin D in Healthy Preterm Infants: A Pilot Study

OBJECTIVE

 The etiology of anemia in premature neonates is multifactorial and may involve anemia of inflammation mediated by hepcidin. Hepcidin expression is suppressed by vitamin D. We aimed to investigate the interrelationship between hepcidin, anemia, and vitamin D status in preterm infants.

STUDY DESIGN

 Preterm infants aged 1 to 5 weeks were prospectively recruited at the neonatal intensive care unit of the Dana Dwek Children Hospital. Blood counts and serum levels of hepcidin, ferritin, iron, 25-hydroxyvitamin D [25(OH)D] and C-reactive protein (CRP) were measured and compared between anemic and nonanemic preterm infants.

RESULTS

 Forty-seven preterm infants (mean ± standard deviation gestational age at birth 32.8 ± 1.1 weeks, 66% males) were recruited. In total, 36% of the preterm infants were vitamin D deficient [25(OH)D < 20 ng/mL] and 15% were anemic. Hepcidin levels were significantly higher in anemic premature infants than in the nonanemic group (55.3 ± 23.9 ng/mL vs. 30.1 ± 16.3 ng/mL, respectively, p < 0.05). No differences were found in iron, ferritin, 25(OH)D, and CRP levels between anemic and nonanemic premature newborn infants. A positive correlation was found between hepcidin and ferritin (R ² = 0.247, p = 0.02) and a negative correlation was found between 25(OH)D and CRP (R ² = 0.1, p = 0.04). No significant correlations were found between 25(OH)D and hepcidin, iron, ferritin, or CRP.

CONCLUSION

 Anemia of prematurity was associated with high hepcidin serum levels. The exact mechanisms leading to anemia and the role of vitamin D warrant further investigation.

KEY POINTS

· Hepcidin levels were significantly higher in anemic premature infants.. · A positive correlation was found between hepcidin and ferritin.. · Negative correlation was found between 25(OH)D and CRP..

Maternal heme-enriched diet promotes a gut pro-oxidative status associated with microbiota alteration, gut leakiness and glucose intolerance in mice offspring

Maternal environment, including nutrition and microbiota, plays a critical role in determining offspring's risk of chronic diseases such as diabetes later in life. Heme iron requirement is amplified during pregnancy and lactation, while excessive dietary heme iron intake, compared to non-heme iron, has shown to trigger acute oxidative stress in the gut resulting from reactive aldehyde formation in conjunction with microbiota reshape. Given the immaturity of the antioxidant defense system in early life, we investigated the extent to which a maternal diet enriched with heme iron may have a lasting impact on gut homeostasis and glucose metabolism in 60-day-old C3H/HeN mice offspring.

As hypothesized, the form of iron added to the maternal diet differentially governed the offspring's microbiota establishment despite identical fecal iron status in the offspring. Importantly, despite female offspring was unaffected, oxidative stress markers were however higher in the gut of male offspring from heme enriched-fed mothers, and were accompanied by increases in fecal lipocalin-2, intestinal para-cellular permeability and TNF-α expression. In addition, male mice displayed blood glucose intolerance resulting from impaired insulin secretion following oral glucose challenge. Using an integrated approach including an aldehydomic analysis, this male-specific phenotype was further characterized and revealed close covariations between unidentified putative reactive aldehydes and bacterial communities belonging to Bacteroidales and Lachnospirales orders.

Our work highlights how the form of dietary iron in the maternal diet can dictate the oxidative status in gut offspring in a sex-dependent manner, and how a gut microbiota-driven oxidative challenge in early life can be associated with gut barrier defects and glucose metabolism disorders that may be predictive of diabetes development.

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Maternal heminic vs. non-heminic iron intake differentially and persistently imprints the offspring's fecal microbiota.

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Males from heme-fed dams exhibit increased gut lumen reactive aldehydes in absence of direct dietary exposure to heme iron.

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Some of the increased reactive aldehydes closely covariated with Orders belonging to Bacteroidales and Lachnospirales.

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Maternal exposure to dietary heme iron impairs gut barrier and glucose tolerance in male offspring.

Urine Proteomics for Noninvasive Monitoring of Biomarkers in Bronchopulmonary Dysplasia

INTRODUCTION

Current techniques to diagnose and/or monitor critically ill neonates with bronchopulmonary dysplasia (BPD) require invasive sampling of body fluids, which is suboptimal in these frail neonates. We tested our hypothesis that it is feasible to use noninvasively collected urine samples for proteomics from extremely low gestational age newborns (ELGANs) at risk for BPD to confirm previously identified proteins and biomarkers associated with BPD.

METHODS

We developed a robust high-throughput urine proteomics methodology that requires only 50 μL of urine. We utilized the methodology with a proof-of-concept study validating proteins previously identified in invasively collected sample types such as blood and/or tracheal aspirates on urine collected within 72 h of birth from ELGANs (gestational age [26 ± 1.2] weeks) who were admitted to a single Neonatal Intensive Care Unit (NICU), half of whom eventually developed BPD (n = 21), while the other half served as controls (n = 21).

RESULTS

Our high-throughput urine proteomics approach clearly identified several BPD-associated changes in the urine proteome recapitulating expected blood proteome changes, and several urinary proteins predicted BPD risk. Interestingly, 16 of the identified urinary proteins are known targets of drugs approved by the Food and Drug Administration.

CONCLUSION

In addition to validating numerous proteins, previously found in invasively collected blood, tracheal aspirate, and bronchoalveolar lavage, that have been implicated in BPD pathophysiology, urine proteomics also suggested novel potential therapeutic targets. Ease of access to urine could allow for sequential proteomic evaluations for longitudinal monitoring of disease progression and impact of therapeutic intervention in future studies.

Lead acetate versus cadmium sulfate in the modulation of main physiological pathways controlling detrusor muscle contractility in rat

Heavy metals have a deleterious effect on lower urinary tract functions. Scant data has been reported about metals’ effect on altering detrusor muscle contractility. Rats were given lead acetate (3, 30 mg/kg), cadmium sulfate (0.1, 1 mg/kg) or ferrous sulfate-iron overload-(3, 30 mg/kg), in a subacute toxicity study (21 days, ip). In-vitro tension experiments were conducted using isolated rat detrusor muscle. Measurement of heavy metal concentrations in blood and tissue homogenates was performed, as well as histopathological examinations. Subacute toxicity induced by treatment with lead and cadmium was manifested as a decrease in EFS, ACh, and ATP-mediated contraction of isolated detrusor muscle. Iron overload only decreased E_MAX of EFS and ACh-mediated contraction. Lead (30 mg/kg) caused an upward shift in the dose response curve of isoprenaline-induced relaxation, with a significant decrease in E_MAX. Lead (30 mg/kg) or cadmium (1 mg/kg) inhibited adenosine (10⁻⁵ M)-induced relaxation. Comparisons to control tissues showed a selective accumulation of metals in the detrusor muscle. Histopathological examinations revealed edema and inflammation in the urinary bladder. Directly added lead (10 mM) inhibited detrusor muscle contraction in-vitro, and its effect was decreased in presence of atropine, and potentiated in presence of TEA, L-NAME, or MB. Cadmium's (0.1 mM) inhibitory effect was reduced in presence of nifedipine or trifluoperazine. In conclusion, lead, cadmium, or iron induce detrusor hypoactivity: The inhibitory effect of lead may be mediated by modulating muscarinic receptors but not the K⁺/NO/cGMP pathway, whereas cadmium inhibitory effect may be mediated by inhibiting the Ca²⁺/calmodulin pathway.

The critical roles of iron during the journey from fetus to adolescent: Developmental aspects of iron homeostasis

Iron is indispensable for human life. However, it is also potentially toxic, since it catalyzes the formation of harmful oxidative radicals in unbound form and may facilitate pathogen growth. Therefore, iron homeostasis needs to be tightly regulated. Rapid growth and development require large amounts of iron, while (especially young) children are vulnerable to infections with iron-dependent pathogens due to an immature immune system. Moreover, unbalanced iron status early in life may have effects on the nervous system, immune system and gut microbiota that persist into adulthood. In this narrative review, we assess the critical roles of iron for growth and development and elaborate how the body adapts to physiologically high iron demands during the journey from fetus to adolescent. As a first step towards the development of clinical guidelines for the management of iron disorders in children, we summarize the unmet needs regarding the developmental aspects of iron homeostasis.

Fetal liver hepcidin secures iron stores in utero

In the adult, the liver-derived hormone hepcidin (HAMP) controls systemic iron levels by blocking the iron-exporting protein ferroportin (FPN) in the gut and spleen, the sites of iron absorption and recycling, respectively. Impaired HAMP expression or FPN responsiveness to HAMP result in iron overload. HAMP is also expressed in the fetal liver but its role in controlling fetal iron stores is not understood. To address this question in a manner that safeguards against the confounding effects of altered maternal iron homeostasis, we generated fetuses harboring a paternally-inherited ubiquitous knock-in of the HAMP-resistant fpnC326Y. Additionally, to safeguard against any confounding effects of altered placental iron homeostasis, we generated fetuses with a liver-specific knock-in of fpnC326Y or knockout of the hamp gene. These fetuses had reduced liver iron stores and hemoglobin, and markedly increased FPN in the liver, but not in the placenta. Thus, fetal liver HAMP operates cell-autonomously to increase fetal liver iron stores. Our findings also suggest that FPN in the placenta is not actively regulated by fetal liver HAMP under normal physiological conditions.

Hepcidin and other indicators of iron status, by alpha-1 acid glycoprotein levels, in a cohort of Mexican infants

The purpose of this study was to describe the changes in iron status indicators at 6 and 12 months of age, controlling by inflammation by measuring alpha-1 acid glycoprotein (AGP). This longitudinal study included 48 healthy-term singleton infants with birth weight ≥ 2500 g, born in hospitals of the Mexican Institute for Social Security. Complete blood count, ferritin, soluble transferrin receptor (sTfR), hepcidin, and AGP were measured in blood at 6 and 12 months of age. sTfR/ferritin ratio and total body iron (TBI) stores were calculated. Hemoglobin and sTfR/ferritin ratio increased with age, while ferritin and TBI decreased. In infants without inflammation, hepcidin, sTfR, and MVC did not show significant changes from 6 to 12 months of age, while ferritin and TBI decreased. In infants with inflammation, hepcidin, TBI, and ferritin levels increased, while hemoglobin and sTfR/ferritin ratio decreased. MVC and sTfR did not change significantly in the presence or absence of inflammation. Hepcidin concentration correlated positively and significantly with ferritin and TBI stores and showed significant negative correlation with sTfR/ferritin ratio. Our study showed that, in absence of inflammation and ID, during the first year of life, physiological changes occur in hemoglobin and ferritin levels as well as in indicators derived from ferritin and sTfR; in contrast, hepcidin and sTfR did not show significant change. However, hepcidin concentration was lower in infants with ID and was higher when inflammation was present, supporting that infants have a functional hepcidin response to changes in iron stores.

Use of Superparamagnetic Iron Oxide Nanoparticles (SPIONs) via Multiple Imaging Modalities and Modifications to Reduce Cytotoxicity: An Educational Review

The aim of the present educational review on superparamagnetic iron oxide nanoparticles (SPIONs) is to inform and guide young scientists and students about the potential use and challenges associated with SPIONs. The present review discusses the basic concepts of magnetic resonance imaging (MRI), basic construct of SPIONs, cytotoxic challenges associated with SPIONs, shape and sizes of SPIONs, site-specific accumulation of SPIONs, various methodologies applied to reduce cytotoxicity including coatings with various materials, and application of SPIONs in targeted delivery of chemotherapeutics (Doxorubicin), biotherapeutics (DNA, siRNA), and positron emission tomography (PET) imaging applications.

Effect of Oral Supplementation of Healthy Pregnant Sows with Sucrosomial Ferric Pyrophosphate on Maternal Iron Status and Hepatic Iron Stores in Newborn Piglets

Simple Summary

In most mammals, including humans, the need for iron increases rapidly in the last period of pregnancy. Therefore, in compliance with World Health Organization (WHO) recommendations, iron supplementation has become a standard procedure even in healthy pregnant women although it carries the risk of iron toxicity and dysregulation of systemic iron homeostasis. Due to physiological and genomic similarities between swine and humans, pigs constitute an useful animal model in nutritional studies during pregnancy. Here, healthy pregnant sows were supplemented with sucrosomial ferric pyrophosphate (SFP), a new non-heme iron formulation, to study its effect on their iron metabolism and that of their progeny. In particular, we aimed at verifying whether supplementation of pregnant sows with SFP will increase the level of low hepatic iron stores in newborn piglets. Results of our study show that SFP does not significantly alter neither systemic iron homeostasis in pregnant sows, nor hepatic iron stores in newborn piglets, which can be used during neonatal period for the maintenance of hematological status. We hypothesize that supplemental iron given orally to pregnant sows is poorly transferred across the placenta.

Abstract

Background: The similarities between swine and humans in physiological and genomic patterns, as well as significant correlation in size and anatomy, make pigs an useful animal model in nutritional studies during pregnancy. In humans and pigs iron needs exponentially increase during the last trimester of pregnancy, mainly due to increased red blood cell mass. Insufficient iron supply during gestation may be responsible for the occurrence of maternal iron deficiency anemia and decreased iron status in neonates. On the other hand, preventive iron supplementation of non-anemic mothers may be of potential risk due to iron toxicity. Several different regimens of iron supplementation have been applied during pregnancy. The majority of oral iron supplementations routinely applied to pregnant sows provide inorganic, non-heme iron compounds, which exhibit low bioavailability and intestinal side effects. The aim of this study was to check, using pig as an animal model, the effect of sucrosomial ferric pyrophosphate (SFP), a new non-heme iron formulation on maternal and neonate iron and hematological status, placental transport and pregnancy outcome; Methods: Fifteen non-anemic pregnant sows were recruited to the experiment at day 80 of pregnancy and randomized into the non-supplemented group (control; n = 5) and two groups receiving oral iron supplementation—sows given sucrosomial ferric pyrophosphate, 60 mg Fe/day (SFP; n = 5) (SiderAL^®, Pisa, Italy) and sows given ferrous sulfate 60 mg Fe/day (Gambit, Kutno, Poland) (FeSO₄; n = 5) up to delivery (around day 117). Biological samples were collected from maternal and piglet blood, placenta and piglet tissues. In addition, data on pregnancy outcome were recorded.; Results: Results of our study show that both iron supplements do not alter neither systemic iron homeostasis in pregnant sows nor their hematological status at the end of pregnancy. Moreover, we did not detect any changes of iron content in the milk and colostrum of iron supplemented sows in comparison to controls. Neonatal iron status of piglets from iron supplemented sows was not improved compared with the progeny of control females. No statistically significant differences were found in average piglets weight and number of piglets per litter between animals from experimental groups. The placental expression of iron transporters varied depending on the iron supplement.

Iron Homeostasis Disruption and Oxidative Stress in Preterm Newborns

Iron is an essential micronutrient for early development, being involved in several cellular processes and playing a significant role in neurodevelopment. Prematurity may impact on iron homeostasis in different ways. On the one hand, more than half of preterm infants develop iron deficiency (ID)/ID anemia (IDA), due to the shorter duration of pregnancy, early postnatal growth, insufficient erythropoiesis, and phlebotomy losses. On the other hand, the sickest patients are exposed to erythrocytes transfusions, increasing the risk of iron overload under conditions of impaired antioxidant capacity. Prevention of iron shortage through placental transfusion, blood-sparing practices for laboratory assessments, and iron supplementation is the first frontier in the management of anemia in preterm infants. The American Academy of Pediatrics recommends the administration of 2 mg/kg/day of oral elemental iron to human milk-fed preterm infants from one month of age to prevent ID. To date, there is no consensus on the type of iron preparations, dosages, or starting time of administration to meet optimal cost-efficacy and safety measures. We will identify the main determinants of iron homeostasis in premature infants, elaborate on iron-mediated redox unbalance, and highlight areas for further research to tailor the management of iron metabolism.

The Role of Iron in the Susceptibility of Neonatal Mice to Escherichia coli K1 Sepsis

Sepsis from Escherichia coli expressing the K1 antigen is a leading cause of death in neonates. In a murine model, E. coli K1 grew rapidly in the peritoneal cavity of neonatal mice, causing fatal disease. In contrast, adult mice cleared the infection. Neonatal mice mounted a rapid and equivalent antimicrobial immune response compared to adult mice. Interestingly, peritoneal fluid from neonatal mice contained significantly more total iron than that of adult mice, which was sufficient to support enhanced E. coli growth. Transient iron overload in adult mice infected with E. coli resulted in 100% mortality. Maternal diet-induced mild iron deficiency decreased offspring peritoneal iron, decreased bacterial growth, and conferred protection against sepsis. Taken together, neonatal susceptibility to E. coli K1 sepsis is enhanced by a localized excess of peritoneal iron that allows for unchecked bacterial growth. Targeting this excess iron may provide a new therapeutic target in human patients.

Screening With Reticulocyte Hemoglobin Increased Iron Sufficiency Among NICU Patients

Introduction:

To increase the rate of iron sufficiency among neonatal intensive care unit (NICU) patients from 16% to >35% within 12 months of implementing standardized assessment of reticulocyte hemoglobin (retHE).

Methods:

We implemented a quality improvement (QI) study to improve iron sufficiency in our out-born level III/IV NICU. We screened 2,062 admissions, of which 622 were eligible based on feeding status at discharge. QI interventions included educational efforts and guideline implementation. Our primary outcome measure was the percentage of patients with their discharge retHE measure within the normal range. We also tracked the process measure of the number of retHE tests performed and a balancing measure of the incidence of elevated retHE among patients receiving iron supplementation. Statistical process control (SPC) charts assessed for special cause variation.

Results:

The percentage of patients with a retHe within the normal range was significantly increased from a mean of 20% to 39% on SPC chart analysis. We measured significantly more retHE values after guideline implementation (11/mo to 24/mo) and found no cases of elevated retHE among patients receiving iron supplementation.

Conclusions:

After the implementation of a standardized guideline, a higher rate of iron sufficiency was found in NICU patients at discharge. This work is generalizable to neonatal populations with the potential for a significant impact on clinical practice.

Comparison of Oral and Parenteral Iron Administration on Iron Homeostasis, Oxidative and Immune Status in Anemic Neonatal Pigs

The present study was to evaluate the consequences of iron status across oral and parenteral iron administrations in prevention of iron deficiency anemia. A total of 24 one-day-old male neonatal piglets were allocated into three groups given non-iron supplementation (NON), intramuscular iron dextran injection (FeDex), and oral administration of ferrous glycine chelate (FeGly), respectively. At day 8, no significant differences in final body weight, average weight gain, and tissue coefficients were observed among three groups (P > 0.05). Both oral FeGly and FeDex injection significantly increased serum iron, ferritin, hemoglobin, and tissue iron deposition (P < 0.05). However, FeDex-injected supplementation resulted in rapidly rising hepcidin levels and hepatic iron deposition (P < 0.05). In addition, compared to parenteral iron supplementation, greater serum IgA level, SOD, and GSH-Px activities, lower expressions of IL-1β and TNF-α in the liver, and lower expressions of IL-6 and TNF-α in the spleen were found in oral iron piglets (P < 0.05). According to our results, oral administration of ferrous glycine chelate improved iron homeostasis, and oxidative and immune status in anemic neonatal pigs.

Uncovering the mechanism of the effects of Paeoniae Radix Alba on iron-deficiency anaemia through a network pharmacology-based strategy

BACKGROUND

Paeoniae Radix Alba, the root of the plant Paeonia lactiflora Pall, is a common blood-enriching drug in traditional Chinese medicine. Its effectiveness in the clinical treatment of anaemia is remarkable, but its potential pharmacologic mechanism has not been clarified.

METHODS

In this study, the potential pharmacologic mechanism of Paeoniae Radix Alba in the treatment of iron-deficiency anaemia was preliminarily elucidated through systematic and comprehensive network pharmacology.

RESULTS

Specifically, we obtained 15 candidate active ingredients from among 146 chemical components in Paeoniae Radix Alba. The ingredients were predicted to target 77 genes associated with iron-deficiency anaemia. In-depth analyses of these targets revealed that they were mostly associated with energy metabolism, cell proliferation, and stress responses, suggesting that Paeoniae Radix Alba helps alleviate iron-deficiency anaemia by affecting these processes. In addition, we conducted a core target analysis and a cluster analysis of protein-protein interaction (PPI) networks. The results showed that four pathways, the p53 signalling pathway, the IL-17 signalling pathway, the TNF signalling pathway and the AGE-RAGE signalling pathway in diabetic complications, may be major pathways associated with the ameliorative effects of Paeoniae Radix Alba on iron-deficiency anaemia. Moreover, molecular docking verified the credibility of the network for molecular target prediction.

CONCLUSIONS

Overall, this study predicted the functional ingredients in Paeoniae Radix Alba and their targets and uncovered the mechanism of action of this drug, providing new insights for advanced research on Paeoniae Radix Alba and other traditional Chinese medicines.

Neonatal iron distribution and infection susceptibility in full term, preterm and low birthweight babies in urban Gambia: study protocol for an observational study

Background: Neonatal infection is the third largest cause of death in children under five worldwide.  Nutritional immunity is the process by which the host innate immune system limits nutrient availability to invading organisms. Iron is an essential micronutrient for both microbial pathogens and their mammalian hosts. Changes in iron availability and distribution have significant effects on pathogen virulence and on the immune response to infection. Our previously published data shows that, during the first 24 hours of life, full-term neonates have reduced overall serum iron. Transferrin saturation decreases rapidly from 45% in cord blood to ~20% by six hours post-delivery. Methods: To study neonatal nutritional immunity and its role in neonatal susceptibility to infection, we will conduct an observational study on 300 full-term normal birth weight (FTB+NBW), 50 preterm normal birth weight (PTB+NBW), 50 preterm low birth weight (PTB+LBW) and 50 full-term low birth weight (FTB+LBW), vaginally-delivered neonates born at Kanifing General Hospital, The Gambia. We will characterize and quantify iron-related nutritional immunity during the early neonatal period and use ex vivo sentinel bacterial growth assays to assess how differences in serum iron affect bacterial growth. Blood samples will be collected from the umbilical cord (arterial and venous) and at serial time points from the neonates over the first week of life. Discussion: Currently, little is known about nutritional immunity in neonates. In this study, we will increase understanding of how nutritional immunity may protect neonates from infection during the first critical days of life by limiting the pathogenicity and virulence of neonatal sepsis causing organisms by reducing the availability of iron. Additionally, we will investigate the hypothesis that this protective mechanism may not be activated in preterm and low birth weight neonates, potentially putting these babies at an enhanced risk of neonatal infection. Trial registration: clinicaltrials.gov ( NCT03353051) 27/11/2017.

Assessing children's exposure to manganese in drinking water using a PBPK model

A previously published human PBPK model for manganese (Mn) in infants and children has been updated with Mn in drinking water as an additional exposure source. Built upon the ability to capture differences in Mn source-specific regulation of intestinal uptake in nursing infants who are breast-fed and formula-fed, the updated model now describes the bioavailability of Mn from drinking water in children of ages 0-18. The age-related features, including the recommended age-specific Mn dietary intake, age-specific water consumption rates, and age-specific homeostasis of Mn, are based on the available human data and knowledge of the biology of essential-metal homeostasis. Model simulations suggest that the impact of adding drinking-water exposure to daily Mn exposure via dietary intake and ambient air inhalation in children is not greater than the impacts in adults, even at a drinking-water concentration that is 2 times higher than the USEPA's lifetime health advisory value. This conclusion was also valid for formula-fed infants who are considered at the highest potential exposure to Mn from drinking water compared to all other age groups. Our multi-route, multi-source Mn PBPK model for infants and children provides insights about the potential for Mn-related health effects on growing children and will thereby improve the level of confidence in properly interpreting Mn exposure-health effects relationships in children in human epidemiological studies.

Neonatal iron distribution and infection susceptibility in full term, preterm and low birthweight babies in urban Gambia: study protocol for an observational study

Background: Neonatal infection is the third largest cause of death in children under five worldwide.  Nutritional immunity is the process by which the host innate immune system limits nutrient availability to invading organisms. Iron is an essential micronutrient for both microbial pathogens and their mammalian hosts. Changes in iron availability and distribution have significant effects on pathogen virulence and on the immune response to infection. Our previously published data shows that, during the first 24 hours of life, full-term neonates have reduced overall serum iron. Transferrin saturation decreases rapidly from 45% in cord blood to ~20% by six hours post-delivery. Methods: To study neonatal nutritional immunity and its role in neonatal susceptibility to infection, we will conduct an observational study on 300 full-term normal birth weight (FTB+NBW), 50 preterm normal birth weight (PTB+NBW), 50 preterm low birth weight (PTB+LBW) and 50 full-term low birth weight (FTB+LBW), vaginally-delivered neonates born at Kanifing General Hospital, The Gambia. We will characterize and quantify iron-related nutritional immunity during the early neonatal period and use ex vivo sentinel bacterial growth assays to assess how differences in serum iron affect bacterial growth. Blood samples will be collected from the umbilical cord (arterial and venous) and at serial time points from the neonates over the first week of life. Discussion: Currently, little is known about nutritional immunity in neonates. In this study, we will increase understanding of how nutritional immunity may protect neonates from infection during the first critical days of life by limiting the pathogenicity and virulence of neonatal sepsis causing organisms by reducing the availability of iron. Additionally, we will investigate the hypothesis that this protective mechanism may not be activated in preterm and low birth weight neonates, potentially putting these babies at an enhanced risk of neonatal infection. Trial registration: clinicaltrials.gov ( NCT03353051) 27/11/2017.

Iron Deficiency and Iron Homeostasis in Low Birth Weight Preterm Infants: A Systematic Review

Iron is an essential micronutrient that is involved in many functions in humans, as it plays a critical role in the growth and development of the central nervous system, among others. Premature and low birth weight infants have higher iron requirements due to increased postnatal growth compared to that of term infants and are, therefore, susceptible to a higher risk of developing iron deficiency or iron deficiency anemia. Notwithstanding, excess iron could affect organ development during the postnatal period, particularly in premature infants that have an immature and undeveloped antioxidant system. It is important, therefore, to perform a review and analyze the effects of iron status on the growth of premature infants. This is a transversal descriptive study of retrieved reports in the scientific literature by a systematic technique. PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines were adapted for the review strategy. The inclusion criteria for the studies were made using the PICO (population, intervention, comparison, outcome) model. Consequently, the systematic reviews that included studies published between 2008–2018 were evaluated based on the impact of iron status on parameters of growth and development in preterm infants.

Current practice of iron prophylaxis in preterm and low birth weight neonates: A survey among Italian Neonatal Units

BACKGROUND

Preterm babies are at high risk of iron deficiency.

METHODS

We investigated current practices regarding iron prophylaxis in preterm and low birth weight newborns among Local Neonatal Units (LNUs, n = 74) and Neonatal Intensive Care Units (NICUs, n = 20) of three Italian Regions (Piemonte, Marche and Lazio).

RESULTS

Birth weight is considered an indicative parameter in only 64% of LNUs and 71% of NICUs, with a significant difference between LNUs in the three regions (86%, 20% and 62%, respectively; p < 0.001). Iron is recommended to infants with a birth weight between 2000 and 2500 g in only 25% of LNUs and 21% of NICUs, and to late-preterm (gestational age between 34 and 37 weeks) in a minority of Units (26% of LNUs, 7% of NICUs).

CONCLUSIONS

Our pilot survey documents a great variability and the urgent need to standardize practices according to literature recommendations.

Iron Supplementation in Suckling Piglets: An Ostensibly Easy Therapy of Neonatal Iron Deficiency Anemia

In pigs, iron deficiency anemia (IDA) is the most prevalent deficiency disorder during the early postnatal period, frequently developing into a serious illness. On the other hand, in humans, only low-birth-weight infants, including premature infants, are especially susceptible to developing IDA. In both human and pig neonates, the initial cause of IDA is low birth iron stores. In piglets this shortage of stored iron results mainly from genetic selection over the past few decades for large litter sizes and high birth weights. As a consequence, pregnant sows cannot provide a sufficient amount of iron to the increasing number of developing fetuses. Supplementation with iron is a common practice for the treatment of IDA in piglets. For decades, the preferred procedure for delivering iron supplements during early life stages has been through the intramuscular injection of a large amount of iron dextran. However, this relatively simple therapy, which in general, efficiently corrects IDA, may generate toxic effects, and by inducing hepcidin expression, may decrease bioavailability of supplemental iron. New iron supplements are considered herein with the aim to combine the improvement of hematological status, blunting of hepcidin expression, and minimizing the toxicity of the administered iron. We propose that iron-deficient piglets constitute a convenient animal model for performing pre-clinical studies with iron supplements.

[Iron and Neurodevelopment]

In the central nervous system, iron is a cofactor of many metabolic processes and synthesis of aminergic neurotransmitters. Iron plays an major function on brain development from the prenatal period to teenage years. The blood-brain barrier modulates concentration of iron in the brain. In case of iron deficiency in the child, the negative impact on the myelinogenesis and synaptogenesis are well proven, with negative effects on psychomotor and cognitive functions. Iron supplementation has a beneficial effect, even if there is no anemia. The consequences of iron deficiency are more harmful as deficiency is early. The main mechanisms involved about iron and brain are reviewed.

Ferritinophagy drives uropathogenic Escherichia coli persistence in bladder epithelial cells

Autophagy is a cellular recycling pathway, which in many cases, protects host cells from infections by degrading pathogens. However, uropathogenic Escherichia coli (UPEC), the predominant cause of urinary tract infections (UTIs), persist within the urinary tract epithelium (urothelium) by forming reservoirs within autophagosomes. Iron is a critical nutrient for both host and pathogen, and regulation of iron availability is a key host defense against pathogens. Iron homeostasis depends on the shuttling of iron-bound ferritin to the lysosome for recycling, a process termed ferritinophagy (a form of selective autophagy). Here, we demonstrate for the first time that UPEC shuttles with ferritin-bound iron into the autophagosomal and lysosomal compartments within the urothelium. Iron overload in urothelial cells induces ferritinophagy in an NCOA4-dependent manner causing increased iron availability for UPEC, triggering bacterial overproliferation and host cell death. Addition of even moderate levels of iron is sufficient to increase and prolong bacterial burden. Furthermore, we show that lysosomal damage due to iron overload is the specific mechanism causing host cell death. Significantly, we demonstrate that host cell death and bacterial burden can be reversed by inhibition of autophagy or inhibition of iron-regulatory proteins, or chelation of iron. Together, our findings suggest that UPEC persist in host cells by taking advantage of ferritinophagy. Thus, modulation of iron levels in the bladder may provide a therapeutic avenue to controlling UPEC persistence, epithelial cell death, and recurrent UTIs.

Correlation between the concentrations of lactoferrin and neutrophil gelatinase-associated lipocalin in meconium

Neutrophil gelatinase-associated lipocalin (NGAL) and lactoferrin (Lf) are among the key components of the innate immune system due to their ability to bind iron with high affinity and thus control inflammation. The aim of this study was to test the use of NGAL and LF measurements in meconium for the assessment of the intrauterine homeostasis. NGAL and Lf concentrations were measured using ELISA kits in all serial meconium portions (n = 81) collected from 20 healthy neonates. Mean ± SD meconium concentration of Lf was 45.07 ± 78.53 µg/g and more than 1000-fold higher compared with that of NGAL at 1.93 ± 2.46 ng/g. The correlation between the two proteins (r = 0.83, p < 0.0001) was found only for portions with Lf concentrations > 25 μg/g. High variability of NGAL and Lf concentrations in meconium and their correlations prove their key role as biomarkers of the fetal condition in utero. NGAL and Lf measured in meconium are candidate biomarkers for fetal iron status.

Development of iron homeostasis in infants and young children

Healthy, term, breastfed infants usually have adequate iron stores that, together with the small amount of iron that is contributed by breast milk, make them iron sufficient until ≥6 mo of age. The appropriate concentration of iron in infant formula to achieve iron sufficiency is more controversial. Infants who are fed formula with varying concentrations of iron generally achieve sufficiency with iron concentrations of 2 mg/L (i.e., with iron status that is similar to that of breastfed infants at 6 mo of age). Regardless of the feeding choice, infants' capacity to regulate iron homeostasis is important but less well understood than the regulation of iron absorption in adults, which is inverse to iron status and strongly upregulated or downregulated. Infants who were given daily iron drops compared with a placebo from 4 to 6 mo of age had similar increases in hemoglobin concentrations. In addition, isotope studies have shown no difference in iron absorption between infants with high or low hemoglobin concentrations at 6 mo of age. Together, these findings suggest a lack of homeostatic regulation of iron homeostasis in young infants. However, at 9 mo of age, homeostatic regulatory capacity has developed although, to our knowledge, its extent is not known. Studies in suckling rat pups showed similar results with no capacity to regulate iron homeostasis at 10 d of age when fully nursing, but such capacity occurred at 20 d of age when pups were partially weaned. The major iron transporters in the small intestine divalent metal-ion transporter 1 (DMT1) and ferroportin were not affected by pup iron status at 10 d of age but were strongly affected by iron status at 20 d of age. Thus, mechanisms that regulate iron homeostasis are developed at the time of weaning. Overall, studies in human infants and experimental animals suggest that iron homeostasis is absent or limited early in infancy largely because of a lack of regulation of the iron transporters DMT1 and ferroportin.

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.

An Elevation of Serum Ferritin Level Might Increase Clinical Risk for the Persistence of Patent Ductus Arteriosus, Sepsis and Bronchopulmonary Dysplasia in Erythropoietin-Treated Very-Low-Birth-Weight Infants

BACKGROUND

The substantial risk of iron overload is not routinely monitored in most of the neonatal intensive care units (NICUs) in Japan; however, blood transfusion is an essential strategy for successfully treating preterm low-birth-weight infants.

OBJECTIVE

The aim of this study was to investigate the iron status and clinical features of infants with a birth weight of <1,500 g, i.e. very-low-birth-weight infants (VLBWIs).

METHODS

This prospective observational study enrolled 176 (82.6%) patients from a total of 213 VLBWIs admitted to our NICU from 2009 to 2014. Clinical information was collected including maternal records and infant morbidity and treatment. Management strategies including enteral iron supplementation, erythropoietin administration and blood transfusion were allowed according to the consensus in Japan. The hematological status was surveyed from birth to 12 postnatal weeks of age. The iron status was determined according to serum iron, unbound iron-binding capacity and serum ferritin. The definition of hyperferritinemia was set as a value of ≥500 ng/ml.

RESULTS

Twenty-four (13.6%) infants displayed hyperferritinemia. A multiple logistic analysis selected 3 associated factors of hyperferritinemia: surgical ligation for patent ductus arteriosus, sepsis and moderate or severe states of bronchopulmonary dysplasia. We also verified that the value of ferritin was significantly correlated with those of aspartate transaminase, creatine kinase and C-reactive protein according to a multilinear regression analysis. After excluding the ferritin data of these outliers, we did not observe any factors associated with hyperferritinemia.

CONCLUSIONS

Hyperferritinemia might be associated with oxygen radical diseases and susceptibility to infection.

Perinatal Factors Affecting Serum Hepcidin Levels in Low-Birth-Weight Infants

BACKGROUND

Hepcidin, an iron-regulatory hormone, plays a key role in preventing iron overload. Few studies have investigated the regulation of hepcidin in low-birth-weight (LBW) infants who are vulnerable to iron imbalance.

OBJECTIVES

To identify perinatal factors associated with serum hepcidin levels in LBW infants.

METHODS

Ninety-two LBW infants with a median gestational age (GA) of 32.6 weeks and birth weight of 1,587 g were prospectively enrolled. Serum hepcidin-25 (Hep25) levels were measured from umbilical cord blood using liquid chromatography-tandem mass spectrometry. The relationship between Hep25 levels and prematurity or other possible hepcidin-regulatory factors was evaluated.

RESULTS

The median Hep25 level was 7.3 ng/mL (interquartile range: 2.85-16.38). log(Hep25) correlated with birth weight (r = 0.229, p = 0.028), log(interleukin-6 [IL-6]) (r = 0.408, p < 0.001), log(erythropoietin) (r = -0.302, p = 0.004), transferrin saturation (r = 0.29, p = 0.005), soluble transferrin receptor (r = -0.500, p < 0.001), and log(ferritin) (r = 0.696, p < 0.001). Serum iron and hemoglobin levels did not correlate with log(Hep25). Hep25 levels were higher among infants with chorioamnionitis and infants born vaginally and lower among infants born to mothers with pregnancy-induced hypertension than among infants without the respective characteristics. Stepwise multiple linear regression analysis confirmed the significant association of log(Hep25) with GA, log(IL-6), log(erythropoietin), and soluble transferrin receptor.

CONCLUSIONS

Among LBW infants, GA, IL-6, erythropoietin, and soluble transferrin receptor were associated with Hep25 levels. Therefore, prematurity, inflammation, hypoxia, and erythropoietic activity may be important perinatal factors that affect hepcidin levels.

Ferroportin Is Essential for Iron Absorption During Suckling, But Is Hyporesponsive to the Regulatory Hormone Hepcidin

BACKGROUND & AIMS

Previous studies have suggested that iron absorption in suckling mammals is refractory to stimuli that normally would decrease absorption in adults. To better understand the regulation of iron absorption during suckling, we have characterized the relationship between hepcidin, ferroportin, and iron absorption at this crucial stage of life.

METHODS

To determine whether ferroportin is involved in iron absorption during suckling, absorption was measured in intestine-specific ferroportin knockout mice. The effect of constitutive hepcidin overexpression on intestinal iron absorption also was investigated in suckling transmembrane serine protease 6 knockout mice. Finally, suckling mice were injected with lipopolysaccharide to induce hepcidin expression. Blood was collected for serum iron analysis, and liver tissue and duodenal enterocytes were collected for gene and protein expression profiles.

RESULTS

Iron absorption was very low in suckling ferroportin knockout mice, indicating that ferroportin is responsible for the majority of the iron absorbed at this time. However, increases in hepcidin during suckling, as seen in transmembrane serine protease 6 knockout mice and in mice injected with lipopolysaccharide, did not affect enterocyte ferroportin levels. Immunofluorescent localization of ferroportin showed that the protein localized to the basolateral membrane of duodenal enterocytes in both suckling and weaned mice.

CONCLUSIONS

These data show that the high iron absorption occurring during suckling is mediated by ferroportin. However, enterocyte ferroportin is hyporesponsive to hepcidin at this time, despite being expressed on the basolateral membrane. Alterations to ferroportin that prevent hepcidin binding during suckling may allow iron absorption to remain high regardless of hepcidin expression levels, reducing the likelihood of iron deficiency during development.

Preweaning iron deficiency increases non-contingent responding during cocaine self-administration in rats

Iron deficiency (ID) is the most prevalent single-nutrient deficiency worldwide. There is evidence that ID early in development (preweaning in rat) causes irreversible neurologic, behavioral, and motor development deficits. Many of these effects have been attributed to damage to dopamine systems, including ID-induced changes in transporter and receptor numbers in the striatum and nucleus accumbens. These mesolimbic dopaminergic neurons are, in part, responsible for mediating reward and thus play a key role in addiction. However, there has been relatively little investigation into the behavioral effects of ID on drug addiction. In 2002, we found that rats made ID from weaning (postnatal day 21) and throughout the experiment acquired cocaine self-administration significantly more slowly than controls and failed to increase responding when the dose of the drug was decreased. In the present study, we assessed addiction for self-administered cocaine in rats with a history of preweaning ID only during postnatal days 4 through 21, and iron replete thereafter. The results showed that while ID did not affect the number of cocaine infusions or the overall addiction-like behavior score, ID rats scored higher on a measure of continued responding for drug than did iron replete controls. This increase in responding, however, was less goal-directed as ID rats also responded more quickly to the non-rewarded manipulandum than did control rats. Thus, while ID early in infancy did not significantly increase addiction-like behaviors for cocaine in this small study, the pattern of data suggests a possible underlying learning or performance impairment. Future studies will be needed to elucidate the exact neuro-behavioral deficits that lead to the increase in indiscriminate responding for drug in rats with a history of perinatal ID.

Lactoferrin and prematurity: a promising milk protein?

Lactoferrin (Lf) is the major whey protein in milk, with multiple beneficial health effects including direct antimicrobial activities, anti-inflammatory effects, and iron homeostasis. Oral Lf supplementation in human preterm infants has been shown to reduce the incidence of sepsis and necrotizing enterocolitis. In preclinical models of antenatal stress and perinatal brain injury, bovine Lf protected the developing brain from neuronal loss, improved connectivity, increased neurotrophic factors, and decreased inflammation. It also supported brain development and cognition. Further, Lf can prevent preterm delivery by reducing proinflammatory factors and inhibiting premature cervix maturation. We review here the latest research on Lf in the field of neonatology.

The reproductive ecology of iron in women

Reproductive ecology focuses on the sensitivity of human reproduction to environmental variation. While reproductive ecology has historically focused on the relationship between energy status and reproductive outcomes, iron status is equally critical to women's reproductive health, given the wide-ranging detrimental effects of iron-deficiency anemia on maternal and infant well-being. This review interprets the vast literature on iron status and women's reproduction through an evolutionary framework. First, it will critique the evidence for iron deficiency caused by blood loss during menstruation, reinterpreting the available data as ecological variation in menses within and between populations of women. Second, it will highlight the scant but growing evidence that iron status is implicated in fertility, a relationship that has deep evolutionary roots. Third, this review proposes a new hypothesis for the transfer of iron from mother to infant via pregnancy and breastfeeding: reproductive iron withholding. In this hypothesis, mothers transfer iron to infants in a manner that helps infants avoid iron-mediated infection and oxidative stress, but trades off with potential risk of maternal and infant iron deficiency. Finally, this review explores two main factors that can modify the relationship between iron status and the gestation-lactation cycle: (1) the relationship between long-term reproductive effort (parity) and iron status and (2) supplementation schemes before and during pregnancy. The review concludes by suggesting continued research into iron homeostasis in women using evolutionary, ecological, and biocultural frameworks.

Asthma as a disruption in iron homeostasis

Over several decades, asthma has evolved from being recognized as a single disease to include a diverse group of phenotypes with dissimilar natural histories, pathophysiologies, responses to treatment, and distinctive molecular pathways. With the application of Occam's razor to asthma, it is proposed that there is one cause underlying the numerous phenotypes of this disease and that the responsible molecular pathway is a deficiency of iron in the lung tissues. This deficiency can be either absolute (e.g. asthma in the neonate and during both pregnancy and menstruation) or functional (e.g. asthma associated with infections, smoking, and obesity). Comparable associations between asthma co-morbidity (e.g. eczema, urticaria, restless leg syndrome, and pulmonary hypertension) with iron deficiency support such a shared mechanistic pathway. Therapies directed at asthma demonstrate a capacity to impact iron homeostasis, further strengthening the relationship. Finally, pathophysiologic events producing asthma, including inflammation, increases in Th2 cells, and muscle contraction, can correlate with iron availability. Recognition of a potential association between asthma and an absolute and/or functional iron deficiency suggests specific therapeutic interventions including inhaled iron.

Lactoferrin, a Pleiotropic Protein in Health and Disease

SIGNIFICANCE

Lactoferrin (Lf) is a nonheme iron-binding glycoprotein strongly expressed in human and bovine milk and it plays many functions during infancy such as iron homeostasis and defense against microorganisms. In humans, Lf is mainly expressed in mucosal epithelial and immune cells. Growing evidence suggests multiple physiological roles for Lf after weaning.

RECENT ADVANCES

The aim of this review is to highlight the recent advances concerning multifunctional Lf activities.

CRITICAL ISSUES

First, we will provide an overview of the mechanisms related to Lf intrinsic synthesis or intestinal absorption as well as its interaction with a wide spectrum of mammalian receptors and distribution in organs and cell types. Second, we will discuss the large variety of its physiological functions such as iron homeostasis, transportation, immune regulation, oxidative stress, inflammation, and apoptosis while specifying the mechanisms of action. Third, we will focus on its recent physiopathology implication in metabolic disorders, including obesity, type 2 diabetes, and cardiovascular diseases. Additional efforts are necessary before suggesting the potential use of Lf as a diagnostic marker or as a therapeutic tool.

FUTURE DIRECTIONS

The main sources of Lf in human cardiometabolic disorders should be clarified to identify new perspectives for future research and develop new strategies using Lf in therapeutics. Antioxid. Redox Signal. 24, 813-836.

Anemia and transfusion in the neonate

Neonatal anemia is a frequent occurrence in neonatal intensive care units. Red blood cell transfusion criteria in case of blood loss are clearly defined but optimal hemoglobin or hematocrit thresholds of transfusion for anemia due to decreased production or increased destruction are less evident. This review focuses on the causes of anemia in the newborn period and the most recent evidence-based treatment options, including transfusion and erythropoiesis-stimulating agents.

Hemoglobin-induced neuronal degeneration in the hippocampus after neonatal intraventricular hemorrhage

Neuronal degeneration following neonatal intraventricular hemorrhage (IVH) is incompletely understood. Understanding the mechanisms of degeneration and cell loss may point toward specific treatments to limit injury. We evaluated the role of hemoglobin (Hb) in cell death after intraventricular injection in neonatal rats. Hb was injected into the right lateral ventricle of post-natal day 7 rats. Rats exposed to anesthesia were used for controls. The CA-1 region of the hippocampus was analyzed via immunohistochemistry, hematoxylin and eosin (H&E) staining, Fluoro-Jade C staining, Western blots, and double-labeling stains. Compared to controls, intraventricular injection of Hb decreased hippocampal volume (27% decrease; p<0.05), induced neuronal loss (31% loss; p<0.01), and increased neuronal degeneration (2.7 fold increase; p<0.01), which were all significantly reduced with the iron chelator, deferoxamine. Hb upregulated p-JNK (1.8 fold increase; p<0.05) and increased expression of the Hb/haptoglobin endocytotic receptor CD163 in neurons in vivo and in vitro (cultured cortical neurons). Hb induced expression of the CD163 receptor, which co-localized with p-JNK in hippocampal neurons, suggesting a potential pathway by which Hb enters the neuron to result in cell death. There were no differences in neuronal loss or degenerating neurons in Hb-injected animals that developed hydrocephalus versus those that did not. Intraventricular injection of Hb causes hippocampal neuronal degeneration and cell loss and increases brain p-JNK levels. p-JNK co-localized with the Hb/haptoglobin receptor CD163, suggesting a novel pathway by which Hb enters the neuron after IVH to result in cell death.

Effects of Environmental Pollutants on Cellular Iron Homeostasis and Ultimate Links to Human Disease

Chronic disease has increased in the past several decades, and environmental pollutants have been implicated. The magnitude and variety of diseases may indicate the malfunctioning of some basic mechanisms underlying human health. Environmental pollutants demonstrate a capability to complex iron through electronegative functional groups containing oxygen, nitrogen, or sulfur. Cellular exposure to the chemical or its metabolite may cause a loss of requisite functional iron from intracellular sites. The cell is compelled to acquire further iron critical to its survival by activation of iron-responsive proteins and increasing iron import. Iron homeostasis in the exposed cells is altered due to a new equilibrium being established between iron-requiring cells and the inappropriate chelator (the pollutant or its catabolite). Following exposure to environmental pollutants, the perturbation of functional iron homeostasis may be the mechanism leading to adverse biological effects. Understanding the mechanism may lead to intervention methods for this major public health concern.

An Overview of Iron in Term Breast-Fed Infants

BACKGROUND

Iron is an essential nutrient for normal growth and neurodevelopment of infants. Iron deficiency (ID) remains the most common micronutrient deficiency worldwide. There are convincing data that ID is associated with negative effects on neurological and psychomotor development.

OBJECTIVES

In this review, we provide an overview of current knowledge of the importance of iron in normal term breast-fed infants with a focus on recommendations, metabolism, and iron requirements.

CONCLUSIONS

Health organizations around the world recommend the introduction of iron-rich foods or iron supplements for growing infants to prevent ID. However, there is no routine screening for ID in infancy. Multicenter trials with long-term follow-up are needed to investigate the association between iron fortification/supplementation and various health outcomes.

Identifying the threshold of iron deficiency in the central nervous system of the rat by the auditory brainstem response

The deleterious effects of anemia on auditory nerve (AN) development have been well investigated; however, we have previously reported that significant functional consequences in the auditory brainstem response (ABR) can also occur as a consequence of marginal iron deficiency (ID). As the ABR has widespread clinical use, we evaluated the ability of this electrophysiological method to characterize the threshold of tissue ID in rats by examining the relationship between markers of tissue ID and severity of ABR latency defects. To generate various levels of ID, female Long-Evans rats were exposed to diets containing sufficient, borderline, or deficient iron (Fe) concentrations throughout gestation and offspring lifetime. We measured hematological indices of whole body iron stores in dams and offspring to assess the degree of ID. Progression of AN ID in the offspring was measured as ferritin protein levels at different times during postnatal development to complement ABR functional measurements. The severity of ABR deficits correlated with the level of Fe restriction in each diet. The sufficient Fe diet did not induce AN ID and consequently did not show an impaired ABR latency response. The borderline Fe diet, which depleted AN Fe stores but did not cause systemic anemia resulted in significantly increased ABR latency isolated to Peak I.The low Fe diet, which induced anemia and growth retardation, significantly increased ABR latencies of Peaks I to IV. Our findings indicate that changes in the ABR could be related to various degrees of ID experienced throughout development.