Ferroportin-Hepcidin Axis in Prepubertal Obese Children with Sufficient Daily Iron Intake

Association of iron deficiency and anemia with obesity among children: A systematic review and meta-analysis

INTRODUCTION

Obesity is a potential risk factor for anemia in children. This systematic review (SR) was undertaken to estimate the association of obesity with iron deficiency (ID) and ID anemia (IDA), in children.

METHODS

A systematic literature search for observational studies was done in PubMed, EMBASE, Scopus, and the Cochrane library, with additional hand-searching. Two reviewers independently screened the search output, included eligible studies, extracted data, and assessed study quality using the National Institutes of Health tool. The main outcomes were association of obesity with anemia (IDA), and ID. Secondary outcomes were hemoglobin level, serum iron, ferritin, transferrin receptor saturation, and hepcidin. Meta-analysis was done using a random-effects model. Comparisons were expressed through pooled OR with 95% CI.

RESULTS

Forty-two studies comprising one cohort, 29 cross-sectional, and 12 case-control studies comparing 16,633 children living with obesity and 32,573 children without obesity were included. The pooled OR (95% CI) for ID was 1.64 (1.22, 2.21), 16 studies, 20,949 children; and 0.78 (0.43, 1.43), 17 studies, 40,022 children, for IDA. The pooled prevalence of ID was 20.07% (14.98, 25.16) among children living with obesity (16 studies, 3147 children), compared to 16.1% (11.82, 20.38) in children without obesity. Children living with obesity had significantly lower levels of hemoglobin, iron, % transferrin saturation, and higher levels of ferritin and hepcidin than children without obesity.

CONCLUSION

There is a significant association between iron deficiency and obesity in children.

Hepcidin and inflammation associated with iron deficiency in childhood obesity - A systematic review

OBJECTIVES

This paper aims to review data on the association of obesity and iron deficiency in children and adolescents, exposing the possible involvement of hepcidin and interleukin-6 (IL-6), obesity's inflammation biomarkers.

DATA SOURCE

Articles from PUBMED and WEB OF SCIENCE database with no chronological limit were reviewed to write this systematic review. Keywords such as children, obesity, iron deficiency, and hepcidin were used. After deleting duplicated and review articles, 91 were screened, and 39 were selected as eligible. Sixteen articles were included because they involved serum hepcidin levels in obese children and adolescents as outcomes.

SUMMARY OF FINDINGS

Finally, those 16 articles were organized in two tables: one includes therapeutic interventions, and the other does not. As hepcidin was discovered in 2000, the first articles that presented serum hepcidin's quantification in obese children and adolescents, homeostasis iron markers, and their possible association with obesity's inflammatory environment began to be published in 2008.

CONCLUSIONS

Obesity's chronic inflammation state leads to the production of IL-6, which acts as a signaling molecule for hepcidin synthesis, resulting in iron deficiency, which is common in obese children and adolescents who respond inadequately to iron supplementation. On the other hand, that population responds adequately to therapeutic intervention programs that lead to weight loss, guaranteeing iron homeostasis improvement. Therefore, perhaps it is time to discuss serum hepcidin level quantification as part of evaluating children and adolescents with iron deficiency, which could guide clinical choices that might lead to better therapeutic outcomes.

Elevated Urinary Hepcidin Level and Hypoferremia in Infants with Febrile Urinary Tract Infection: A Prospective Cohort Study

To evaluate the kinetics of serum and urinary hepcidin levels along with anemia-related parameters during the infection course of infants with febrile urinary tract infection (UTI), we enrolled febrile infants aged one to four months in this prospective study. Febrile patients with UTI were allocated into Escherichia coli (E. coli) or non-E. coli groups according to urine culture results. Septic workup, blood hepcidin, iron profile, urinalysis, and urinary hepcidin-creatinine ratio were collected upon admission and 3 days after antibiotic treatment. In total, 118 infants were included. On admission, the febrile UTI group showed a significant reduction in serum iron level and a significant elevation of urinary hepcidin-creatinine ratio compared to the febrile control counterpart. Moreover, urinary hepcidin-creatinine ratio had the highest odds ratio, 2.01, in logistics regression analysis. After 3 days of antibiotic treatment, hemoglobin and the urinary hepcidin-creatinine ratio were significantly decreased. Patients with an E. coli UTI had a significantly decreased urinary hepcidin-creatinine ratio after 3 days of antibiotics treatment, whereas the non-E. coli group showed insignificant changes. Our study suggested that the urinary hepcidin-creatinine ratio elevated during acute febrile urinary tract infection and significantly decreased after 3 days of antibiotics treatment, especially in E. coli UTI.

Associations between Oxidant/Antioxidant Status and Circulating Adipokines in Non-Obese Children with Prader-Willi Syndrome

Oxidative stress is implicated in the pathophysiology of Prader-Willi syndrome (PWS), but there are no data on these disorders in non-obese children with PWS. Therefore, the presented study examined total oxidant capacity (TOC), total antioxidant capacity (TAC), the oxidative stress index (OSI), and adipokine levels in 22 non-obese children with PWS during dietary intervention and growth hormone treatment compared with 25 non-obese healthy children. Serum concentrations of TOC, TAC, nesfatin-1, leptin, hepcidin, ferroportin, and ferritin were determined using immunoenzymatic methods. We found that TOC concentrations were higher by 50% (p = 0.006) in patients with PWS than in healthy children, but no significant differences in TAC concentrations were observed between these groups. The OSI was higher in children with PWS than in the controls (p = 0.002). We found positive associations between TOC values and the percentage of the Estimated Energy Requirement, body mass index (BMI) Z-score, percentage of fat mass, and leptin, nesfatin-1, and hepcidin concentrations in patients with PWS. A positive association was also found between the OSI and nesfatin-1 levels. These observations suggest that higher daily energy intake and weight gain may be accompanied by an increasing prooxidant state in these patients. Adipokines such as leptin, nesfatin-1, or hepcidin may also play a role in the prooxidant state in non-obese children with PWS.

Increased hepcidin levels and non-alcoholic fatty liver disease in obese prepubertal children: a further piece to the complex puzzle of metabolic derangements

INTRODUCTION

Several studies on obese youths and adults have reported increased hepcidin levels, which seems to be related to metabolic and iron metabolism alterations. The complete mechanisms involved in hepcidin increase remain to be elucidated, and particularly its role in the development of other known complications such as Nonalcoholic Fatty Liver Disease (NAFLD). NAFLD in prepubertal children might be of special interest in understanding the underlying mechanisms.

METHODS

Anthropometric measurements, liver ultrasonography, lipid profile, liver function, oxidative stress, inflammatory state, and iron metabolism were studied in 42 obese prepubertal children and 33 healthy controls. We, therefore, evaluated the presence of possible correlations between Hepcidin and the other metabolic variables, and the possible association between NAFLD and iron metabolism.

RESULTS

Hepcidin levels were significantly increased in the obese prepubertal children (p=0.001) with significant differences between obese children with and without NAFLD (p=0.01). Blood iron was lower in obese children (p=0.009). In the obese group, a negative correlation between hepcidin and both blood iron levels (p=0.01) and LagPHASE (p=0.02) was found. In addition, a positive association between hepcidin and NAFLD (p=0.03) was detected.

CONCLUSIONS

We suggest that an increase in hepcidin levels may represent an early step in iron metabolism derangements and metabolic alterations, including NAFLD, in prepubertal obese children.

The human symbiont Bacteroides thetaiotaomicron promotes diet-induced obesity by regulating host lipid metabolism

The gut microbiome plays an important role in lipid metabolism. Consumption of a high-fat diet (HFD) alters the bacterial communities in the gut, leading to metabolic disorders. Several bacterial species have been associated with diet-induced obesity, nonalcoholic fatty liver disease, and metabolic syndrome. However, the mechanisms underlying the control of lipid metabolism by symbiotic bacteria remain elusive. Here, we show that the human symbiont Bacteroides thetaiotaomicron aggravates metabolic disorders by promoting lipid digestion and absorption. Administration of B. thetaiotaomicron to HFD-fed mice promoted weight gain, elevated fasting glucose levels, and impaired glucose tolerance. Furthermore, B. thetaiotaomicron treatment upregulated the gene expression of the fatty acid transporter and increased fatty acid accumulation in the liver. B. thetaiotaomicron inhibits expression of the gene encoding a lipoprotein lipase inhibitor, angiopoietin-like protein 4 (ANGPTL4), thereby increasing lipase activity in the small intestine. In particular, we found that B. thetaiotaomicron induced the expression of hepcidin, the master regulator of iron metabolism and an antimicrobial peptide, in the liver. Hepcidin treatment resulted in a decrease in ANGPTL4 expression in Caco-2 cells, whereas treatment with an iron chelator restored ANGPTL4 expression in hepcidin-treated cells. These results indicate that B. thetaiotaomicron-mediated regulation of iron storage in intestinal epithelial cells may contribute to increased fat deposition and impaired glucose tolerance in HFD-fed mice.

Factors associated with childhood anaemia in Afro-descendant communities in Alagoas, Brazil

OBJECTIVE

To investigate factors associated with anaemia in preschool children.

DESIGN

A home survey was conducted in 2018. Anaemia in children (capillary blood Hb level < 110 g/l) was the outcome, and socio-economic, demographic and health factors of the mother and child were the independent variables. The measure of association was the prevalence ratio, and its 95 % CI was calculated using Poisson's regression with robust variance and hierarchical selection of independent variables.

SETTING

Afro-descendants communities living in the state of Alagoas, northeast Brazil.

PARTICIPANTS

Children aged 6-59 months and their mothers (n 428 pairs).

RESULTS

The prevalence of child anaemia was 38·1 % (95 % CI 33·5, 42·7). The associated factors with child anaemia were male sex, age < 24 months, larger number of residents at home (> 4), relatively taller mothers (highest tertile) and higher z-score of BMI for age, after further adjustment for wealth index, vitamin A supplementation in the past 6 months and clinical visit in the last 30 d.

CONCLUSIONS

The high prevalence of anaemia observed reveals a relevant public health problem amongst children under five from the quilombola communities of Alagoas. Considering the damage caused to health and multiplicity of risk factors associated with anaemia, the adoption of intersectoral strategies that act on modifiable risk factors and increase vigilance concerning those that are not modifiable becomes urgent.

Anthropometric Markers and Iron Status of 6-12-Year-Old Thai Children: Associations and Predictors

Introduction

Obesity may be associated with poor iron status. The objective of this study was to investigate the association between different indices of iron status and anthropometric measurements in Thai children.

Materials and Methods

Anthropometry (weight, height, waist circumference (WC), and body composition assessed by bioelectrical impedance analysis) and iron indices were measured in 336 Thai children aged 6-12 years. Iron deficiency (ID) was defined using two or more of the following: (1) %transferrin saturation (%Tsat) < 16%; (2) serum ferritin (SF) < 15 μg/mL; and (3) soluble transferrin receptor (sTfR) > 5 mg/L. Iron deficiency anaemia (IDA) was defined as haemoglobin < WHO age cutoff combined with ID. Overweight and obesity were defined as body mass index (BMI) standard deviation score (SDS) ≥ +1 SDS or +2 SDS, respectively (WHO growth reference).

Results

BMI SDS was significantly positively correlated with sTfR and SF (sTfR, r: 0.209, p < 0.001; SF, r: 0.214, p < 0.001) and negatively correlated with %Tsat (r: -0.132, p = 0.013). Correlations between WC SDS and %fat mass and each iron marker were similar. The percentage with low SF was significantly lower than that using other individual markers. ID prevalence was not significantly different between normal-weight and overweight/obesity groups although a significantly higher proportion of overweight/obese children had sTfR >5 mg/L. Puberty and menarche were significant predictors of ID (puberty adjusted OR: 2.20, 95% CI: 0.43, 11.25; menarche adjusted OR: 6.11, 95% CI: 1.21, 30.94).

Conclusion

Greater adiposity was associated with poorer iron status. However, SF may not be a good indicator of iron status in Thai children, particularly in those who are overweight/obese, whereas sTfR merits further investigation.

Association between Consumption of Cow's Milk and Iron Deficiency Anemia in Children: Are There Roles for Hepcidin-25/Ferroportin? A Case-Control Study

Systemic iron homeostasis is regulated by the interaction of the peptide hormone, hepcidin and the iron exporter, ferroportin. The objective was to investigate the relationship between the consumption of cow's milk and iron deficiency anemia in children 2-10 years old and its association with the hepcidin-25 and ferroportin concentrations. The study population consisted of 187 prepubescent children of similar ideal body weight (IBW:90-120%); 82 children with iron deficiency anemia (37girls and 45boys; 4.27 ± 0.28 years) and 105 (47girls and 58boys; 4.25 ± 0.34 years) healthy age-sex-matched controls. Serum fasting hepcidin-25/ferroportin concentrations were measured by enzyme immunoassay in all subjects. Mean cow's milk consumption in the anemic group (373 ± 248 mL/d) tended to be higher than that in the control group (320 ± 226 mL/d), but the result was not statistically significant (p = 0.063).The mean hepcidin-25 level was significantly higher in the anemic group (19.5 ± 18.4 ng/mL) than in the healthy controls (11.0 ± 10.7, p < 0.001). The mean ferroportin level was lower in the anemic group (21.04 ± 5.74 ng/mL) than in the healthy controls (22.68 ± 4.77 ng/ml, p = 0.037). Consuming cow's milk was not associated with IDA in prepubertal children, provided that it was adequately supplemented with iron-enriched foods. We observed a significant increase in hepcidin-25 levels and a decrease in ferroportin levels in children with iron deficiency anemia compared with healthy controls. Children who consumed more cow's milk had higher levels of hepcidin-25. Iron deficiency anemia is not a concern when cow's milk is given to children if the complementary foods are rich in iron.

Disordered serum erythroferrone and hepcidin levels as indicators of the spontaneous abortion occurrence during early pregnancy in humans

Spontaneous abortion is a common, detrimental outcome of pregnancy, and can be induced by a variety of factors, including pathophysiological conditions and socioeconomic circumstances. Despite numerous studies examining the aetiology of spontaneous abortion, there is limited understanding of the disordered iron transportation between mother and fetus through the placenta. Recently, erythroferrone (ERFE) was recognized as a novel negative regulator of hepcidin that can elevate nutritional iron absorption and macrophagic iron egress for enhanced erythropoiesis. However, its diagnostic significance in different disease conditions associated with iron remains poorly understood. In the current study, we discovered disordered maternal iron homeostasis in women who had spontaneous abortions during early pregnancy, as characterized by increased serum iron and hepcidin levels, and conversely, reduced serum ERFE levels, compared to healthy control individuals and women with normal pregnancy. Comprehensive statistical analyses revealed the correlation between different variables and pregnancy status, signifying the pronounced diagnostic value of an increased ratio of serum hepcidin and ERFE (HE ratio) in recognizing adverse pregnancy status. In contrast to previous non-selective discrete surrogates, such as iron, hepcidin and ferritin, the HE ratio may otherwise stand for a novel and more representative hallmark for early spontaneous abortion.

Iron Metabolism in Obesity and Metabolic Syndrome

Obesity is an excessive adipose tissue accumulation that may have detrimental effects on health. Particularly, childhood obesity has become one of the main public health problems in the 21st century, since its prevalence has widely increased in recent years. Childhood obesity is intimately related to the development of several comorbidities such as nonalcoholic fatty liver disease, dyslipidemia, type 2 diabetes mellitus, non-congenital cardiovascular disease, chronic inflammation and anemia, among others. Within this tangled interplay between these comorbidities and associated pathological conditions, obesity has been closely linked to important perturbations in iron metabolism. Iron is the second most abundant metal on Earth, but its bioavailability is hampered by its ability to form highly insoluble oxides, with iron deficiency being the most common nutritional disorder. Although every living organism requires iron, it may also cause toxic oxygen damage by generating oxygen free radicals through the Fenton reaction. Thus, iron homeostasis and metabolism must be tightly regulated in humans at every level (i.e., absorption, storage, transport, recycling). Dysregulation of any step involved in iron metabolism may lead to iron deficiencies and, eventually, to the anemic state related to obesity. In this review article, we summarize the existent evidence on the role of the most recently described components of iron metabolism and their alterations in obesity.

Examining the link between dose-dependent dietary iron intake and Alzheimer's disease through oxidative stress in the rat cortex

BACKGROUND

Neurodegenerative diseases such as Alzheimer's and Parkinson's disease are characterized by the progressive deterioration of the structure and function of the nervous system. A number of environmental risk factors including potentially toxic elements such as iron, lead to negative effects on many metabolic reactions as well as neuroprotection. The aim of this study is to reveal whether long-term iron overload is one of the underlying factors in the pathogenesis of Alzheimer's disease (AD).

METHODS

15 young-adult male rats were randomly divided into 5 groups treated with iron through drinking water for 4 months. Following feeding, the iron content, reduced glutathione (GSH), and hydrogen peroxide (H₂O₂) levels of cortex tissues were measured. Specific enzyme activities were determined spectrophotometrically. mRNA expression profiles were measured using real-time PCR (qPCR).

RESULTS

Iron levels were elevated in case of non-toxic (0.87 and 3 μg/mL) iron administration. However, no changes were observed in toxic (30 and 300 μg/mL) iron administration. GSH and H₂O₂ levels altered with long-term iron overload. Glutathione peroxidase (GPx) enzyme activities significantly increased in all groups, while glutathione S-transferase (GST) activity increased only in case of 0.87 and 30 μg/mL iron administration. Expression levels of neuroprotective and AD-related genes were altered by 3 μg/mL iron overload in a dose-dependent manner. The expression and activity of acetylcholinesterase (AChE) were elevated at 3 μg/mL iron concentration.

CONCLUSION

The findings of the present study allow us to conclude that long-term dietary iron intake, especially at a dose of 3 μg/mL demonstrates negative effects on the rat cortex by provoking antioxidant metabolism and AD pathology in a dose-dependently.

Effects of Pubertal Status and Inflammation on the Use of Ferritin to Define Iron Deficiency in Children With Overweight or Obesity

Background and aims:

A worldwide increase in childhood overweight (OW) and obesity (OB) has been reported. OB is an inflammatory state which affects iron metabolism and the sensibility of the tests to detect iron deficiency (ID). Our aim was to evaluate the adequacy of current ferritin cut-offs to define ID in children with OW/OB.

Methods:

This cross-sectional study included 152 children (54% girls) aged (median [Q1-Q3]) 11 (8-13) years with OW/OB. Complete blood count and iron metabolism were evaluated. Low ferritin, transferrin saturation (TSat), and anemia were defined by age- and sex-specific cut-offs recommended by National Guidelines. Iron intake was assessed in a subgroup (n = 80) by a 24-hour dietary recall. Analyses were made according to pubertal development and ferritin tertiles.

Results:

The overall prevalence of low ferritin, TSat, and anemia was 2.6%, 23.8%, and 5.2%, respectively. Among pre-pubertal children (n = 87), the frequency of low TSat rose across ferritin tertiles (P < .05), whereas it decreased among pubertal children (n = 65; P < .005). Cases of anemia among pre-pubertal children were found in the highest ferritin tertile, whereas 4/6 anemia cases in pubertal children were found in the lowest ferritin tertile (<39 µg/L). Pubertal children within the lowest ferritin tertile + low TSat (n = 11) showed lower hemoglobin (–9%; P < .005) and hematocrit (–8%, P < .01) than those in the same tertile + normal TSat (n = 16). The overall prevalence of children with ferritin < 39 µg/L + low TSat was 9.2%.

Conclusions:

Higher ferritin cut-off values are required to define ID in children with OW/OB. Such cut-off remains to be validated in larger, multi-ethnic cohorts of children with OW/OB.