Pregnancy and maternal iron deficiency stimulate hepatic CRBPII expression in rats

Perinatal iron deficiency causes sex-dependent alterations in renal retinoic acid signaling and nephrogenesis

Long-term alterations in kidney structure and function have been observed in offspring exposed to perinatal stressors such as iron deficiency (ID), albeit the mechanisms underlying these changes remain unclear. Here, we assessed how perinatal ID alters renal vitamin A metabolism, an important contributor to nephrogenesis, in the developing kidney. Pregnant Sprague Dawley rats were fed either an iron-restricted or -replete diet throughout gestation, and offspring were studied on postnatal day (PD)1 and 28. Maternal iron restriction results in reduced renal retinoid concentrations in male and female offspring on PD1 (P=.005). Nephron endowment was reduced by 21% in male perinatal ID offspring (P<.001), whereas it was unaffected in perinatal ID females. Perinatal ID resulted in sex-dependent changes in kidney retinoid synthesis and metabolism, whereby male offspring exhibited increased expression of Raldh2 and Rar/Rxr isoforms, while females exhibited unchanged or decreased expression (all interaction P<.05). Male perinatal ID offspring exhibit sex-specific enhancements of retinoic acid pathway signaling components on PD1, including Gdnf (P<.01) and Ctnnb1 (P<.01), albeit robust upregulation of RA transcriptional target Stra6 was observed in both sexes (P=.006). On PD28, perinatal ID resulted in elevated renal retinoid concentrations (P=.02) coinciding with enhanced expression of Raldh2 (P=.04), but not any Rar isoform or Rxr. Further, perinatal ID resulted in robust upregulation of Gdnf, Ret, Ctnnb1, associated with further increases in both Cxcr4 and Stra6 (all P<.01) at PD28. Together, these data suggest perinatal ID results in sustained sex-dependent perturbations in vitamin A metabolism, which likely underlie sex-specific reductions in nephron endowment.

Retinol-binding protein 2 (RBP2): biology and pathobiology

Retinol-binding protein 2 (RBP2; originally cellular retinol-binding protein, type II (CRBPII)) is a 16 kDa cytosolic protein that in the adult is localized predominantly to absorptive cells of the proximal small intestine. It is well established that RBP2 plays a central role in facilitating uptake of dietary retinoid, retinoid metabolism in enterocytes, and retinoid actions locally within the intestine. Studies of mice lacking Rbp2 establish that Rbp2 is not required in times of dietary retinoid-sufficiency. However, in times of dietary retinoid-insufficiency, the complete lack of Rbp2 gives rise to perinatal lethality owing to RBP2 absence in both placental (maternal) and neonatal tissues. Moreover, when maintained on a high-fat diet, Rbp2-knockout mice develop obesity, glucose intolerance and a fatty liver. Unexpectedly, recent investigations have demonstrated that RBP2 binds long-chain 2-monoacylglycerols (2-MAGs), including the canonical endocannabinoid 2-arachidonoylglycerol, with very high affinity, equivalent to that of retinol binding. Crystallographic studies establish that 2-MAGs bind to a site within RBP2 that fully overlaps with the retinol binding site. When challenged orally with fat, mucosal levels of 2-MAGs in Rbp2 null mice are significantly greater than those of matched controls establishing that RBP2 is a physiologically relevant MAG-binding protein. The rise in MAG levels is accompanied by elevations in circulating levels of the hormone glucose-dependent insulinotropic polypeptide (GIP). It is not understood how retinoid and/or MAG binding to RBP2 affects the functions of this protein, nor is it presently understood how these contribute to the metabolic and hormonal phenotypes observed for Rbp2-deficient mice.

Iron encapsulated microstructured gel beads using an emulsification-gelation technique for an alginate-caseinate matrix

Iron-deficiency anemia is an important health problem in global public issues, and development of iron fortifiers in diets is essential for the decrease of iron deficiency. However, there are problems for iron fortification in food because the common bioavailable iron compounds would contribute to iron-promoted lipid oxidation and unpleasant iron odor, presenting an adverse food quality. Ferrous fumarate loaded microstructured gel beads were prepared by an emulsification-gelation method using an alginate-caseinate matrix, and the gel network was formed by crosslinking of Ca²⁺ or Fe²⁺. Internal gelated beads showed relatively symmetrical and homogeneous spheres with no adhesion due to the simultaneous release of Fe²⁺ to initiate gelation in situ. External gelated beads displayed an irregular and adhesive structure, probably because the random contact between Na-ALG and Ca²⁺ occurred on the droplet surface, and the immediately gelated hardening layer provided a delay for further Ca²⁺ diffusion. The gel beads exhibited a lag phase in the promotion of lipid oxidation of the emulsion and restrained the iron odor release from ferrous fumarate. Ferrous ion release from microstructured gel beads in the simulated gastric juice was obviously delayed before a more progressive high release in the simulated intestinal juice, beneficial for iron absorption in the duodenum. The iron encapsulated microstructured gel beads might be developed as a promising safe iron fortifier by relieving lipid oxidation and iron odor.

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.

Co-cultured Lepista sordida and Pholiota nameko polysaccharide-iron(iii) chelates exhibit good antioxidant activity

In the present study, the structural characteristics and antioxidant activities of polysaccharide from the co-cultured Lepista sordida and Pholiota nameko and its polysaccharide-iron(iii) chelates were determined. Two polysaccharide fractions named CP-1 and CP-3 were isolated previously from polysaccharide of the fermentation liquid of the co-cultured Lepista sordida and Pholiota nameko. And their chemical structures were measured by FT-IR infrared spectroscopy, TG analysis, X-ray diffraction and ¹H NMR spectroscopy. The results suggested that polysaccharides were chelated with iron(iii) by –OH and –COOH groups, forming a stable structure of β-FeOOH and improving crystallinity. Furthermore, the antioxidant activities of polysaccharide-iron(iii) chelates exhibited stronger hydroxyl radical and superoxide radical scavenging activity than the polysaccharides. Therefore, the polysaccharide-iron(iii) chelates could be used as a potential iron supplement.

In the present study, the structural characteristics and antioxidant activities of polysaccharide from the co-cultured Lepista sordida and Pholiota nameko and its polysaccharide-iron(iii) chelates were determined.

Animal Models of Normal and Disturbed Iron and Copper Metabolism

Research on the interplay between iron and copper metabolism in humans began to flourish in the mid-20th century, and diseases associated with dysregulated homeostasis of these essential trace minerals are common even today. Iron deficiency is the most frequent cause of anemia worldwide, leading to significant morbidity, particularly in developing countries. Iron overload is also quite common, usually being the result of genetic mutations which lead to inappropriate expression of the iron-regulatory hormone hepcidin. Perturbations of copper homeostasis in humans have also been described, including rare genetic conditions which lead to severe copper deficiency (Menkes disease) or copper overload (Wilson disease). Historically, the common laboratory rat (Rattus norvegicus) was the most frequently utilized species to model human physiology and pathophysiology. Recently, however, the development of genetic-engineering technology combined with the worldwide availability of numerous genetically homogenous (i.e., inbred) mouse strains shifted most research on iron and copper metabolism to laboratory mice. This created new opportunities to understand the function of individual genes in the context of a living animal, but thoughtful consideration of whether mice are the most appropriate models of human pathophysiology was not necessarily involved. Given this background, this review is intended to provide a guide for future research on iron- and copper-related disorders in humans. Generation of complementary experimental models in rats, swine, and other mammals is now facile given the advent of newer genetic technologies, thus providing the opportunity to accelerate the identification of pathogenic mechanisms and expedite the development of new treatments to mitigate these important human disorders.

Preparation and Characterization of a Novel Polysaccharide-Iron(III) Complex in Auricularia auricula Potentially Used as an Iron Supplement

Iron deficiency anemia has been a widespread disease. As an effective and stable iron supplement, the physiochemical properties of the polysaccharide iron complex have been widely studied. In this study, we characterized a novel polysaccharide-iron(III) complex extracted in an edible fungal species Auricularia auricular (AAPS-iron(III)). The highest iron content (28.40%) in the AAPS-iron(III) complex was obtained under the optimized preparation conditions including an AAPS to FeCl3∙ 6H2O ratio of 2:3 (w/w), a pH value of 8.0 in solution, a reaction temperature of 50°C, and a reaction time of 3 h. The physical and chemical properties of the AAPS-iron(III) complex were characterized by qualitative and quantitative analyses using scanning electron microscope, particle size distribution, thermogravimetric analyzer, Fourier transform infrared spectroscopy, circular dichroism, and 1H nuclear magnetic resonance. Result showed that, although the iron was bound to the polysaccharide, it was released under artificial gastrointestinal conditions. The AAPS-iron(III) complex exhibited high stability (under 50-256°C) and water solubility. The AAPS-iron(III) complex also showed high antioxidant activity in vitro, demonstrating an additional health benefit over other typical nonantioxidant iron nutritional supplements. Furthermore, the AAPS-iron(III) complex showed high efficiency on the treatment of the iron deficiency anemia in the model rats. Therefore, the AAPS-iron(III) complex can be used as a nutritional fortifier to supply iron in industrial processing and to assist the treatment of iron deficiency anemia.

Antioxidant, immunomodulatory, oxidative stress inhibitory and iron supplementation effect of Astragalus membranaceus polysaccharide-iron (III) complex on iron-deficiency anemia mouse model

As iron supplement, the antioxidant activities of APS-iron (III) complex were comprehensively evaluated by 5-axe cobweb charts, which indicated the APS-iron (III) complex had a certain antioxidant activity and been weaker than that of APS. The results of immunological activity experiments indicated the stimulation index increased with APS-iron (III) complex concentration increase. When the concentration of the APS-iron (III) complex was 50 μg/mL, the lymphocytes proliferation increased by 35.7% compared with APS. APS-iron (III) complex also had better complement fixing activity than APS, 0.589 mg/mL of which achieved 50% complement fixing activities. Through the iron supplement experiments on iron-deficiency anemia mouse model, we found the APS-iron (III) complex faster increased hemoglobin concentration, SOD, CAT and faster decreased MDA to the normal level than Niferex and ferrous sulfate. Histological results revealed that the tissue sections were clear without obvious pathological changes and bone marrow had most hematopoietic cells from APS-iron (III) complex rat group, which also proved the APS-iron (III) complex had no significant side effects. Therefore, APS-iron (III) complex may be developed as a multifunctional iron supplement for clinical application.

The effect of maternal iron deficiency on zinc and copper levels and on genes of zinc and copper metabolism during pregnancy in the rat

Fe deficiency is relatively common in pregnancy and has both short- and long-term consequences. However, little is known about the effect on the metabolism of other micronutrients. A total of fifty-four female rats were fed control (50 mg Fe/kg) or Fe-deficient diets (7·5 mg/kg) before and during pregnancy. Maternal liver, placenta and fetal liver were collected at day 21 of pregnancy for Cu and Zn analysis and to measure expression of the major genes of Cu and Zn metabolism. Cu levels increased in the maternal liver (P=0·002) and placenta (P=0·018) of Fe-deficient rats. Zn increased (P&lt;0·0001) and Cu decreased (P=0·006) in the fetal liver. Hepatic expression of the Cu chaperones antioxidant 1 Cu chaperone (P=0·042) and cytochrome c oxidase Cu chaperone (COX17, P=0·020) decreased in the Fe-deficient dams, while the expression of the genes of Zn metabolism was unaltered. In the placenta, Fe deficiency reduced the expression of the chaperone for superoxide dismutase 1, Cu chaperone for superoxide dismutase (P=0·030), ceruloplasmin (P=0·042) and Zn transport genes, ZRT/IRT-like protein 4 (ZIP4, P=0·047) and Zn transporter 1 (ZnT1, P=0·012). In fetal liver, Fe deficiency increased COX17 (P=0·020), ZRT/IRT-like protein 14 (P=0·036) and ZnT1 (P=0·0003) and decreased ZIP4 (P=0·004). The results demonstrate that Fe deficiency during pregnancy has opposite effects on Cu and Zn levels in the fetal liver. This may, in turn, alter metabolism of these nutrients, with consequences for development in the fetus and the neonate.

Preparation and stability of nano-scaled gel beads of λ-carrageenan bound with ferric ions

Iron-deficiency anemia (IDA) is a major global public health problem, and the iron fortifiers in diet are clearly needed in the prevention and improvement of IDA for humans. A novel nano-scaled gel beads of λ-carrageenan (λ-car) specifically binding with ferric ions was developed to be a promising iron fortifier with no adverse organoleptic changes on food. Turbidity measurement, thermogravimetric analysis and Fourier transform infrared spectroscopy confirmed the successful chelating. The gel beads of λ-car-Fe³⁺ complex showed good dispersibility and solvent stability. The in vitro cell viability of HepG2 cells treated with λ-car-Fe³⁺ was over 75% at 5 mg/mL of ferric ions, indicating a significant cytotoxicity reduction of ferric ions. The stability of λ-car-Fe³⁺ complex powder was obviously increased against browning during 60 d storage with zein coating, which was attributed to the prevention of moisture permeation. Zein coated gel beads also performed a slow release of ferric ions in simulated gastrointestinal juices, resulting from the compact and hydrophobic zein surface delaying the dissociation of λ-car-Fe³⁺ in acidic environment. This λ-car-Fe³⁺ complex would have a great potential as a safe iron fortifier and facilitate iron supplementary with the advantage to relieve the side effects of iron ions.