Selenium, iron, copper, and zinc levels and copper-to-zinc ratios in serum of patients at different stages of viral hepatic diseases

Viral hepatic diseases, especially those induced by the hepatitis B virus, can progress into more serious pathological outcomes and eventually to hepatocellular carcinoma. A growing body of evidence indicates that many trace elements play important roles in a number of carcinogenic processes that proceed through various mechanisms. To examine the status of trace elements during the development of hepatic carcinoma, we determined the selenium, iron, copper, and zinc levels and copper-to-zinc ratios in the serum of patients at different stages of viral hepatic disease. We observed significant changes in the selenium, iron copper, and zinc levels in the serum of patients having hepatocellular carcinoma, relative to those of healthy controls (p<0.05). The mean serum copper level in patients with hepatocellular carcinoma was significantly higher than that of the control group. In contrast, the mean selenium, iron, and zinc levels in patients having hepatocellular carcinoma were significantly lower than those of the control group. In addition, the mean zinc level in the serum of patients with hepatic cirrhosis was significantly lower than that of the control group (p<0.05). Moreover, we found markedly elevated Cu: Zn ratios (p<0.05) in patients having hepatic cirrhosis or hepatocellular carcinoma. Our findings imply that the levels of some trace elements, such as selenium, iron, copper, and zinc, and Cu:Zn ratios, might serve as biomarkers for the increased severity of viral hepatic damage.     

Differing expression of genes involved in non-transferrin iron transport across plasma membrane in various cell types under iron deficiency and excess

We studied the effect of iron deficiency, i.e., 24-h preincubation in iron-free medium, and the effect of high level of non-transferrin iron, i.e., the preincubation in ferric citrate medium containing 500 muM ferric citrate, on the expression of DMT1, Dcytb, ferroportin, hephaestin, and ceruloplasmin in various functional types of human cells. The expression of these proteins potentially involved in non-transferrin iron transport across cell membranes was tested on mRNA level by quantitative real-time PCR as well as on protein level by western blot analysis in Caco-2 (colorectal carcinoma), K562 (erythroleukemia), and HEP-G2 (hepatocellular carcinoma) cells. We found that changes in non-transferrin iron availability, i.e., iron deficiency and high level of non-transferrin iron, affect the expression of tested proteins in a cell type-specific manner. We also demonstrated that changes in the expression on mRNA level do not often correlate with relevant changes on protein level.     

Role of the liver in the regulation of circadian rhythm of blood iron in rats]

In experiments with Wistar rats there was discovered statistically significant circadian rhythm of serum iron concentration reaching its maximum in the evening, minimum--early in the morning, and having an amplitude of at least 20% of the mesor. The reciprocal interrelations between circadian cycles of iron content in blood and liver were also found. The synchronization of blood iron level with lipid peroxidation products in membranous liver structures, as well as serum alanine aminotransferase activity, and their inversion with respect to the circadian rhythms of liver RES absorption ability and liver iron content are considered to be a proof of liver participation in regulation of iron exchange temporal organization in rats.     

Non-anemic iron deficiency,oral iron supplementation,and oxidative damage in college-aged females

Oxidative damage, as indicated by protein carbonyl and lipid hydroperoxide concentrations, was assessed in the plasma of college-aged females with adequate iron status and with non-anemic iron deficiency before and after eight weeks of iron supplementation. At baseline, the mean serum ferritin, iron, transferrin saturation, and total iron binding capacity of the iron deficient group (n = 13) was significantly different from the iron adequate controls (n = 24). Mean plasma lipid hydroperoxide and protein carbonyl concentrations did not differ between groups at baseline. Following eight weeks of iron supplementation, the mean serum ferritin, iron, and transferrin saturation significantly increased and the total iron binding capacity significantly decreased in the iron deficient group. No significant differences in plasma lipid hydroperoxide or protein carbonyl concentrations were found between groups at the end of the study period. When plasma lipid hydroperoxide and protein carbonyl concentrations of subjects within groups were compared at the start versus at the end of the study, no significant differences were found for either group. Neither non-anemic iron deficiency nor its treatment with oral iron supplements is associated with oxidative damage in the plasma of college-aged females.     

Enhanced erythrocytic lipid peroxides level in rabbits after repeated parental administration of iron

An experiment was conducted in rabbits to evaluate the possible involvement of oxidative stress in iron-overload animals. Ten adult female New Zealand white rabbits were divided into 2 equal groups with 5 animals each. Group II animals received intramuscular iron dextran injections (120 mg/kg body wt/day) on alternate day for 14 days (8 injections), while Group I animals did not receive any iron supplementation to serve as negative controls. The blood samples were collected by cardiac puncture before the start of iron dosing and thereafter, at weekly intervals for 28 days. The samples were processed to measure blood iron concentration, packed cell volume, erythrocytic lipid peroxide (LPO) level, superoxide dismutase (SOD) and catalase (CAT) activities. The blood iron concentration showed a rising trend following repeated iron administration, and the mean level recorded on day 14 was significantly higher than respective day 0 value. LPO level remained significantly higher from day 14 onwards till the end of the observation period of 14 more days after cessation of iron adminstration. Erythrocytic superoxide dismutase activities showed a transient significant rise on day 7, and thereafter, showed a declining trend, but remained statistically comparable to respective day 0 or corresponding value of the control animals.     

Gastrins, iron and colorectal cancer

This minireview explores the connections between circulating gastrins, iron status and colorectal cancer. The peptide hormone gastrin is a major regulator of acid secretion and a potent mitogen for normal and malignant gastrointestinal cells. Gastrins bind two ferric ions with μM affinity and, in the case of non-amidated forms of the hormone, iron binding is essential for biological activity. The ferric ion ligands have been identified as glutamates 7, 8 and 9 in the 18 amino acid peptide glycine-extended gastrin. An interaction between gastrin and transferrin was first demonstrated by covalent crosslinking techniques, and has been recently confirmed by surface plasmon resonance. We have therefore proposed that gastrins act as catalysts in the loading of transferrin with iron. Several recent lines of evidence, including the facts that the concentrations of circulating gastrins are increased in mice and humans with the iron overload disease haemochromatosis, and that transferrin saturation positively correlates with circulating gastrin concentrations, suggest that gastrins may be involved in iron homeostasis. In addition the recognition that ferric ions may play an unexpected role in the biological activity of non-amidated gastrins may assist in the development of new therapies for colorectal carcinoma.     

Gastrins, iron homeostasis and colorectal cancer

The peptide hormone gastrin has been identified as a major regulator of acid secretion and a potent mitogen for normal and malignant gastrointestinal cells. The importance of gastric acid in the absorption of dietary iron first became evident 50 years ago when iron deficiency anemia was recognized as a long-term consequence of partial gastrectomy. This review summarizes the connections between circulating gastrins, iron status and colorectal cancer. Gastrins bind two ferric ions with micromolar affinity and, in the case of non-amidated forms of the hormone, iron binding is essential for biological activity in vitro and in vivo. The demonstration of an interaction between gastrin and transferrin by biochemical techniques led to the proposal that gastrins catalyze the loading of transferrin with iron. Several lines of evidence, including the facts that the concentrations of circulating gastrins are increased in mice and humans with the iron overload disease hemochromatosis and that transferrin saturation positively correlates with circulating gastrin concentration, suggest the potential involvement of gastrins in iron homeostasis. Conversely, recognition that ferric ions play an unexpected role in the biological activity of gastrins may assist in the development of useful therapies for colorectal carcinoma and other disorders of mucosal proliferation in the gastrointestinal tract.     

Tumour promotion versus tumour suppression in chronic hepatic iron overload

Although iron‐catalysed oxidative damage is presumed to be a major mechanism of injury leading to cirrhosis and hepatocellular carcinoma in hemochromatosis, these events have been difficult to recapitulate in an animal model. In this study, we evaluated regulators of hepatocarcinogenesis in a rodent model of chronic iron overload. Sprague–Dawley rats were iron loaded with iron dextran over 6 months. Livers were harvested and analysed for markers of oxidative stress, as well as the following proteins: p53, murine double minute 2, the Shc proteins p66, p52, p46; β‐catenin, CHOP, C/EBPα and Yes‐associated protein. In this model, iron loading is associated with hepatocyte proliferation, and indices of oxidative damage are mildly increased in tandem with augmented antioxidant defenses. Alterations potentially favouring carcinogenesis included a modest but significant decrease in p53 levels and increases in p52, p46 and β‐catenin levels compared with control livers. Countering these factors, the iron‐loaded livers demonstrated a significant decrease in CHOP, which has recently been implicated in the development of hepatocellular carcinoma, as well as a reciprocal increase in C/EBPα and decrease in Yes‐associated protein. Our results suggest that chronic iron overload elicits both tumour suppressive as well as tumour‐promoting mechanisms in rodent liver. Copyright © 2015 John Wiley & Sons, Ltd.     

Aluminium and iron air pollution near an iron casting and aluminium foundry in Turin district (Italy)

This work reports the results of an environmental survey carried out in an industrial area in the Province of Turin: its main aim is to assess the levels of iron and aluminium in the outside air during the period from July to September to assess the influence of industrial activity (a cast-iron and aluminium foundry) which is interrupted during the month of August, on the level of metals present in the air. Conducting the analysis during this period of time made it possible to avoid the confounding effect of pollution due to domestic central heating. The measurements were taken from nine areas at different distances from the foundry in the area and according to the direction of the prevailing winds, as deduced from the historical data. The results of this survey show a statistically significant difference in iron and aluminium levels in the outside air in the geographic areas between the two main periods examined: during August (no foundry activity) v/s July-September (foundry activity). The values recorded are: Aluminium 0.4+/-0.45 microg/m(3) v/s 1.12+/-1.29 microg/m(3) (p<0.0001); Iron 0.95+/-0.56 microg/m(3) v/s 1.6+/-1.0 microg/m(3) (p<0.0001). There were no statistically significant differences between the nine sampling points from the point of view of the sampling sites, climate conditions and wind directions. We found no correlation with car traffic, in terms of the number of vehicles, and metals. The values of iron tended to be higher in the areas farther away from the foundry site in the areas located along the path of the prevailing winds.     

Chromium,iron, selenium,and zinc levels in serum from preschool children in central Taiwan

The elemental levels of chromium, iron, selenium, and zinc in the sera from 81 preschool children (3-6 yr old) who lived in central Taiwan were determined. One-half of them, at 12 kindergartens in two metropolitan precincts, lived in the Taichung city (TCPC) and the rest lived in 10 urban townships (TUTPC), which had been randomly selected. A blood sample was collected from each subject; sera were freeze-dried, and chromium, iron, selenium, and zinc were measured using instrumental neutron activation analysis (INAA). Results were considered in relation to environmental conditions and the sex and age of the preschool children. The mean concentrations of zinc serum in the TCPC group were statistically significantly higher than those of TUTPC group (p<0.01). The iron sera from girls are higher than those of boys, in both TCPC and TUTPC groups, and show a statistically significant difference (p<0.05) in the TUTPC group. In the TCPC group, Cr contents were positively correlated with age. Elemental concentrations of sera were compared across ages and country.     

Zinc deficiency-induced iron accumulation, a consequence of alterations in iron regulatory protein-binding activity, iron transporters, and iron storage proteins

One consequence of zinc deficiency is an elevation in cell and tissue iron concentrations. To examine the mechanism(s) underlying this phenomenon, Swiss 3T3 cells were cultured in zinc-deficient (D, 0.5 microM zinc), zinc-supplemented (S, 50 microM zinc), or control (C, 4 microM zinc) media. After 24 h of culture, cells in the D group were characterized by a 50% decrease in intracellular zinc and a 35% increase in intracellular iron relative to cells in the S and C groups. The increase in cellular iron was associated with increased transferrin receptor 1 protein and mRNA levels and increased ferritin light chain expression. The divalent metal transporter 1(+)iron-responsive element isoform mRNA was decreased during zinc deficiency-induced iron accumulation. Examination of zinc-deficient cells revealed increased binding of iron regulatory protein 2 (IRP2) and decreased binding of IRP1 to a consensus iron-responsive element. The increased IRP2-binding activity in zinc-deficient cells coincided with an increased level of IRP2 protein. The accumulation of IRP2 protein was independent of zinc deficiency-induced intracellular nitric oxide production but was attenuated by the addition of the antioxidant N-acetylcysteine or ascorbate to the D medium. These data support the concept that zinc deficiency can result in alterations in iron transporter, storage, and regulatory proteins, which facilitate iron accumulation.     

The apparent effect of iron supplementation on serum selenium levels in teenage pregnancy

Numerous studies have suggested a significant role of selenium in the prevention of gynecological carcinoma. These were epidemiological and prospective in humans and therapeutic in laboratory animals. However, no studies have been reported regarding the normal serum selenium levels during pregnancy. The maternal total blood volume increases 30-50% during the second and third trimesters, resulting in lower measured serum levels for those metabolites, which are not increased significantly during pregnancy. A longitudinal study of the serum selenium levels in teenage pregnancy during the last two trimesters and 3 mo postpartum showed progressive elevation from 49 +/- 7 microg/dL after the 32nd week of pregnancy to 114 +/- 7 microg/dL at term, which was statistically significant (p < or = 0.001). Prenatal supplementation with 18 mg of iron per day prevented this elevation. The results of this study suggest that serum selenium levels in women normally double during pregnancy and this doubling is prevented by the minimal daily supplementation of 18 mg of iron, which may be due to increased absorption of selenium into the erythrocytes and incorporation into the glutathione peroxidase enzyme.     

Ischemia-induced brain iron delocalization: Effect of iron chelators

Tissue damage in cerebral ischemia may be produced by acidosis-induced delocalization of intracellular iron which acts as a catalyst in oxidative reactions. Acidosis was induced either by homogenization and incubation of rat cortical homogenates in acidified buffers or by submitting hyperglycemic rats to complete ischemia, a procedure that leads to intracellular lactic acidosis. The level of low molecular weight species (LMWS) iron was measured after filtration of tissue homogenates through a 10,000 Mr ultrafiltration membrane. When cortical tissue was homogenized in buffer pH 7, the level of LMWS iron was equal to 0.21 μg/g. It was significantly enhanced by acidification of the homogenization medium, reaching 0.34 μg/g at pH 6 and 0.75 μg/g at pH 5. When the tissue was homogenized in water, the LMWS iron level reached 0.17 μg/g in normoglycemic rats and 0.38 μg/g (p < 0.5) in hyperglycemic rats. Both aerobic incubation of homogenates for 1 h at 37°C and inclusion of EDTA in the homogenization medium led to further increases in the iron level. In order to demonstrate the deleterious role of iron in brain ischemia, the effect of treatment with bipyridyl, an iron-chelating agent, was assessed by measuring regional brain edema by the specific gravity method, 24 h following induction of thrombotic brain infarction. The treatment significantly attenuated the development of brain edema, reducing the water content of the infarcted area by about 2.5%. Taken together, these results support the hypothesis that a significant component of brain ischemic injury involves an iron-dependent mechanism.     

The influence of lactoferrin, orally administered, on systemic iron homeostasis in pregnant women suffering of iron deficiency and iron deficiency anaemia

Iron is a fundamental element for humans as it represents an essential component of many proteins and enzymes. However, this element can also be toxic when present in excess because of its ability to generate reactive oxygen species. This dual nature imposes a tight regulation of iron concentration in the body. In humans, systemic iron homeostasis is mainly regulated at the level of intestinal absorption and, until now, no regulated pathways for the excretion of iron have been found. The regulation and maintenance of systemic iron homeostasis is critical to human health. Excessive iron absorption leads to iron-overload in parenchyma, while low iron absorption leads to plasma iron deficiency, which manifests as hypoferremia (iron deficiency, ID) and ID anaemia (IDA). ID and IDA are still a major health problem in pregnant women. To cure ID and IDA, iron supplements are routinely prescribed. The preferred treatment of ID/IDA, consisting in oral administration of iron as ferrous sulphate, often fails to exert significant effects on hypoferremia and may also cause adverse effects. Lactoferrin (Lf), an iron-binding glycoprotein abundantly found in exocrine secretions of mammals, is emerging as an important regulator of systemic iron homeostasis. Recent data suggest that this natural compound, capable of interacting with the most important components of iron homeostasis, may represent a valuable alternative to iron supplements in the prevention and cure of pregnancy-associated ID and IDA. In this review, recent advances in the molecular circuits involved in the complex cellular and systemic iron homeostasis will be summarised. The role of Lf in curing ID and IDA in pregnancy and in the maintenance of iron homeostasis will also be discussed. Understanding these mechanisms will provide the rationale for the development of novel therapeutic alternatives to ferrous sulphate oral administration in the prevention and cure of ID and IDA.     

Co-factors in liver disease: the role of HFE-related hereditary hemochromatosis and iron

The severity of liver disease and its presentation is thought to be influenced by many host factors. Prominent among these factors is the level of iron in the body. The liver plays an important role in coordinating the regulation of iron homeostasis and is involved in regulating the level of iron absorption in the duodenum and iron recycling by the macrophages. Iron homeostasis is disturbed by several metabolic and genetic disorders, including various forms of hereditary hemochromatosis. This review will focus on liver disease and how it is affected by disordered iron homeostasis, as observed in hereditary hemochromatosis and due to HFE mutations. The types of liver disease covered herein are chronic hepatitis C virus (HCV) infection, alcoholic liver disease (ALD), non-alcoholic fatty liver disease (NAFLD), end-stage liver disease, hepatocellular carcinoma (HCC) and porphyria cutanea tarda (PCT).     

Macrophage iron, hepcidin, and atherosclerotic plaque stability

Hepcidin has emerged as the key hormone in the regulation of iron balance and recycling. Elevated levels increase iron in macrophages and inhibit gastrointestinal iron uptake. The physiology of hepcidin suggests an additional mechanism by which iron depletion could protect against atherosclerotic lesion progression. Without hepcidin, macrophages retain less iron. Very low hepcidin levels occur in iron deficiency anemia and also in homozygous hemochromatosis. There is defective retention of iron in macrophages in hemochromatosis and also evidently no increase in atherosclerosis in this disorder. In normal subjects with intact hepcidin responses, atherosclerotic plaque has been reported to have roughly an order of magnitude higher iron concentration than that in healthy arterial wall. Hepcidin may promote plaque destabilization by preventing iron mobilization from macrophages within atherosclerotic lesions; the absence of this mobilization may result in increased cellular iron loads, lipid peroxidation, and progression to foam cells. Marked downregulation of hepcidin (e.g., by induction of iron deficiency anemia) could accelerate iron loss from intralesional macrophages. It is proposed that the minimally proatherogenic level of hepcidin is near the low levels associated with iron deficiency anemia or homozygous hemochromatosis. Induced iron deficiency anemia intensely mobilizes macrophage iron throughout the body to support erythropoiesis. Macrophage iron in the interior of atherosclerotic plaques is not exempt from this process. Decreases in both intralesional iron and lesion size by systemic iron reduction have been shown in animal studies. It remains to be confirmed in humans that a period of systemic iron depletion can decrease lesion size and increase lesion stability as demonstrated in animal studies. The proposed effects of hepcidin and iron in plaque progression offer an explanation of the paradox of no increase in atherosclerosis in patients with hemochromatosis despite a key role of iron in atherogenesis in normal subjects.     

Thalassaemia,iron, and pregnancy.

Haematological values of 35 pregnant women with beta-thalassaemia trait were followed during pregnancy. The discriminant function, calculated from haematological indices, was of no value in diagnosing beta-thalassaemia trait during pregnancy. Initially patients were given iron supplements only if the serum iron and total iron binding capacity levels indicated iron deficiency, but bone marrow biopsies performed in the first 22 patients at 32 weeks indicated deficient iron stores. These patients were therefore given iron irrespective of their serum iron level. All subsequent patients with beta-thalassaemia were also put on iron routinely at booking. Retrospectively the patients were divided into two groups. Patients in group 1 (18 patients) had received iron for less than 12 weeks, and their haemoglobin levels fell significantly during pregnancy (P less than 0-001). Haemoglobin levels in 16 patients who had received iron for more than 12 weeks (group 2), however, did not fall significantly during pregnancy (P less than 0-6). It is suggested (contrary to common practice) that patients with beta-thalassaemia trait should be given iron supplements during pregnancy. Serum folate and vitamin B12 levels did not change significantly in these patients and there was no increase in the incidence of maternal or fetal complications.     

Neuromelanin associated redox-active iron is increased in the substantia nigra of patients with Parkinson's disease

Degeneration of dopaminergic neurones during Parkinson's disease is most extensive in the subpopulation of melanized-neurones located in the substantia nigra pars compacta. Neuromelanin is a dark pigment produced in the dopaminergic neurones of the human substantia nigra and has the ability to bind a variety of metal ions, especially iron. Post-mortem analyses of the human brain have established that oxidative stress and iron content are enhanced in association with neuronal death. As redox-active iron (free Fe2+ form) and other transition metals have the ability to generate highly reactive hydroxyl radicals by a catalytic process, we investigated the redox activity of neuromelanin (NM)-aggregates in a group of parkinsonian patients, who presented a statistically significant reduction (- 70%) in the number of melanized-neurones and an increased non-heme (Fe3+) iron content as compared with a group of matched-control subjects. The level of redox activity detected in neuromelanin-aggregates was significantly increased (+ 69%) in parkinsonian patients and was highest in patients with the most severe neuronal loss. This change was not observed in tissue in the immediate vicinity of melanized-neurones. A possible consequence of an overloading of neuromelanin with redox-active elements is an increased contribution to oxidative stress and intraneuronal damage in patients with Parkinson's disease.     

Expression profiles of iron transport molecules along the duodenum

Duodenal biopsies are considered a suitable source of enterocytes for studies of dietary iron absorption. However, the expression level of molecules involved in iron absorption may vary along the length of duodenum. We aimed to determine whether the expression of molecules involved in the absorption of heme and non‐heme iron differs depending on the location in the duodenum. Analysis was performed with samples of duodenal biopsies from 10 individuals with normal iron metabolism. Samples were collected at the following locations: (a) immediately post‐bulbar, (b) 1–2 cm below the papilla of Vater and (c) in the distal duodenum. The gene expression was analyzed at the mRNA and protein level using real‐time PCR and Western blot analysis. At the mRNA level, significantly different expression of HCP1, DMT1, ferroportin and Zip8 was found at individual positions of duodenum. Position‐dependent expression of other molecules, especially of FLVCR1, HMOX1 and HMOX2 was also detected but with no statistical significances. At the protein level, we observed statistically significantly decreasing expression of transporters HCP1, FLVCR1, DMT1, ferroportin, Zip14 and Zip8 with advancing positions of duodenum. Our results are consistent with a gradient of diminishing iron absorption along the duodenum for both heme and non‐heme iron.     

Impact of iron particles in groundwater on the UV inactivation of bacteriophages MS2 and T4

AIMS: To investigate the impact of iron particles in groundwater on the inactivation of two model viruses, bacteriophages MS2 and T4, by 254-nm ultraviolet (UV) light. METHODS AND RESULTS: One-litre samples of groundwater with high iron content (from the Indianapolis Water Company, mean dissolved iron concentration 1.3 mg l(-1)) were stirred vigorously while exposed to air, which oxidized and precipitated the dissolved iron. In parallel samples, ethylenediaminetetra-acetic acid (EDTA) was added to chelate the iron and prevent formation of iron precipitate. The average turbidity in the samples without EDTA (called the 'raw' samples) after 210 min of stirring was 2.7 +/- 0.1 NTU while the average turbidity of the samples containing EDTA (called the 'preserved' samples) was 1.0 +/- 0.1 NTU. 'Raw' and 'preserved' samples containing bacteriophage MS2 were exposed to 254-nm UV light at doses of 20, 40, or 60 mJ (cm(2))(-1), while samples containing bacteriophage T4 were exposed to 2 or 5 mJ (cm(2))(-1), using a low pressure UV collimated beam. The UV inactivation of both phages in the 'raw' groundwater was lower than in the EDTA-'preserved' groundwater to a statistically significant degree (alpha = 0.05), due to the association of phage with the UV-absorbing iron precipitate particles. A phage elution technique confirmed that a large fraction of the phage that survived the UV exposures were particle-associated. CONCLUSIONS: Phages that are associated with iron oxide particles in groundwater are shielded from UV light to a measurable and statistically significant degree at a turbidity level of 2.7 NTU when the phage particle association is induced under experimental conditions. SIGNIFICANCE AND IMPACT OF THE STUDY: While the particle association of the phage in this study was induced experimentally, the findings provide further evidence that certain particles in natural waters and wastewaters (e.g. iron oxide particles) may have the potential to shield viruses from UV light.