Repletion of copper-deficient rats with dietary copper restores duodenal hephaestin protein and iron absorption

Copper (Cu) deficiency in rats reduces the relative concentration of duodenal hephaestin (Hp), reduces iron (Fe) absorption, and causes anemia. An experiment was conducted to determine whether these effects could be reversed by dietary Cu repletion. Five groups of eight weanling male rats each were used. Group 1 was fed a Cu-adequate diet (5.0 mg Cu/kg; CuA) and Group 2 was fed a Cu-deficient diet (0.25 mg Cu/kg; CuD) for 28 days. The rats were fed 1.0 g each of their respective diets labeled with 59Fe (37 kBq/g), and the amount of label retained was measured one week later by whole-body-counting (WBC). Group 3 was fed a CuA diet and Groups 4 and 5 were fed a CuD diet for 28 days. Group 5 was then fed the CuA diet for another week while Groups 3 and 4 continued on their previous regimens. Rats in Groups 3, 4, and 5 were fed 1.0 g of diet labeled with 59Fe, and the amount of label retained was measured by WBC one week later. Rats were killed and duodenal enterocytes isolated for Hp protein analysis, whole blood was analyzed for hematological parameters, and various organs for 59Fe content. CuD rats absorbed less (P<0.05) Fe than CuA rats, the relative amount of duodenal Hp was less (P<0.05) in CuD rats, and the CuD rats developed anemia. After the CuD rats had been repleted with Cu for one week, Fe retention rose to values even higher (P<0.05) than those in CuA rats. After two weeks, the relative amount of duodenal Hp was higher (P<0.05) than normal, and most signs of anemia were reversed. Liver 59Fe was elevated in CuD rats, but was restored to normal upon Cu repletion. These findings suggest a strong association between duodenal Hp abundance and Fe absorption in the CuD rat, and that reduced Fe absorption is an important factor in the cause of anemia.     

Maternal iron supplementation attenuates the impact of perinatal copper deficiency but does not eliminate hypotriiodothyroninemia nor impaired sensorimotor development

Copper, iron and iodine/thyroid hormone (TH) deficiencies disrupt brain development. Neonatal Cu deficiency causes Fe deficiency and may impact thyroidal status. One purpose of these studies was to determine the impact of improved iron status following Cu deficiency by supplementing the diet with iron. Cu deficiency was produced in pregnant Holtzman [Experiment 1 (Exp. 1)] or Sprague-Dawley [Experiment 2 (Exp. 2)] rats using two different diets. In Exp. 2, dietary Fe content was increased from 35 to 75 mg/kg according to NRC guidelines for reproduction. Cu-deficient (CuD) Postnatal Day 24 (P24) rats from both experiments demonstrated lower hemoglobin, serum Fe and serum triiodothyronine (T3) concentrations. However, brain Fe was lower only in CuD P24 rats in Exp. 1. Hemoglobin and serum Fe were higher in Cu adequate (CuA) P24 rats from Exp. 2 compared to Exp. 1. Cu- and TH-deficient rats from Exp. 2 exhibited a similar sensorimotor functional deficit following 3 months of repletion. Results suggest that Cu deficiency may impact TH status independent of its impact on iron biology. Further research is needed to clarify the individual roles for Cu, Fe and TH in brain development.     

Early and advanced glycation end-products are increased in dietary copper deficiency

The hypothesis that nonenzymatic glycosylation of proteins (glycation) contributes to damage associated with dietary copper deficiency has depended largely on indirect evidence. Thus far, the observation of an elevated percentage of glycated hemoglobin in copper-deficient rats has provided the only direct evidence of an increase in glycation. We sought further direct evidence of increased glycation in copper deficiency. Male weanling rats were fed a copper-adequate (CuA, 6.4 mg Cu/kg diet) or copper-deficient diet (CuD, 0.4 mg Cu/kg diet) for 5 weeks. Rats fed the CuD diet were copper deficient as judged by depressed organ copper concentrations and a variety of indirect indices. Measurements of hemoglobin A(1) and serum fructosamine (both early glycation end-products) as well as serum pentosidine (an advanced glycation end-product) indicated that all three compounds were elevated in CuD rats relative to CuA rats. This finding further supports the view that glycation is enhanced and thus may contribute to defects associated with dietary copper deficiency.     

Effect of copper deficiency on the lymphatic absorption of cholesterol, plasma chylomicron clearance, and postheparin lipase activities

The lymphatic absorption of cholesterol and plasma clearance of chylomicrons were investigated in Cu-deficient rats (CuD) fed 0.5 mg Cu/kg diet, as compared with Cu-adequate control rats (CuA) fed 7.5 mg/kg diet. Cholesterol absorption was measured by the 14C-radioactivity appearing in the mesenteric lymph at hourly intervals for 8 hr after an intraduodenal dose of [14C]cholesterol. The plasma clearance of chylomicrons was measured at 3, 6, and 10 min after an intravenous dose of chylomicrons labeled in vivo with [3H]retinyl ester. Cumulative [14C]cholesterol absorption and total lymphatic output of cholesterol were significantly decreased in CuD at 4 hr and thereafter, with no change in percentage distribution of free and esterified cholesterol. Over an 8-hr period, 7.3% of the dose was absorbed by CuD and 9.2% by CuA. When [3H]chylomicrons, obtained from a CuD or CuA donor rat, were injected into CuD and CuA recipient rats, the label was cleared faster in CuD during the first 3 min. At 6 and 10 min, however, no significant difference in percentage clearance of the dose was observed between the groups. The half-life (t1/2) of [3H]chylomicrons and the total 3H-radioactivity taken up by the liver during the entire 10-min period did not differ between the groups, regardless of the source of chylomicrons. The activities of both endothelial lipoprotein lipase (LPL) and hepatic lipase (HL) in postheparin plasma were markedly lower in CuD. As expressed in micromoles fatty acid released/hr/ml plasma, the activities of LPL in CuD and CuA were 32.6 +/- 1.9 and 45.6 +/- 1.3, respectively. A similar magnitude of difference was also observed in HL activity. The data provide evidence that copper deficiency impairs the intestinal transport of cholesterol and the peripheral lipolysis of chylomicrons. The data, however, strongly suggest that the hepatic uptake of chylomicron remnants via the apo-E-dependent mechanism may not be impaired in Cu deficiency.     

Neointima formation in the rat carotid artery is exacerbated by dietary copper deficiency

Dietary copper is an essential trace element with roles in both functional and structural aspects of the cardiovascular system. In particular, the vascular response to inflammatory stimuli is known to be significantly augmented in copper-deficient rats. The current study was designed to quantify the extent of injury-induced neointimal proliferation and stenosis in rats fed diets either adequate or deficient in copper. Male, weanling Sprague-Dawley rats were fed purified diets that were either adequate (CuA; 5.6 microg Cu/g) or deficient (CuD; 0.3 microg Cu/g) in copper for 4 weeks. Balloon injury was induced in the left external carotid arteries. Fourteen days after injury, histomorphometric analysis of cross-sections from carotid arteries showed increased neointimal formation in the CuD group compared with the CuA controls (neointima/media ratio: 4.55 +/- 0.93 vs 1.45 +/- 0.2, respectively). These results correspond with data indicating that the activity of Cu/Zn-superoxide dismutase (SOD) is depressed in rats fed this CuD diet. Because superoxide anion and redox status are known to play a key role in the extent of neointimal formation in response to injury, we propose that the exaggerated neointimal proliferation seen in the CuD group is the result of the diminished Cu/Zn-SOD activity.     

Proinflammatory effects of copper deficiency on neutrophils and lung endothelial cells

Dietary copper deficiency increases the accumulation of circulating neutrophils in the rat lung microcirculation. This process includes neutrophil adhesion to, migration along, and emigration though the vascular endothelium. The current study was designed to examine the role of copper in each of these steps. Neutrophils were isolated from rats fed either a copper-adequate (CuA, 6.1 microg Cu/g diet) or copper-deficient diet (CuD, 0.3 microg Cu/g diet) for 4 weeks. First, transient and firm adhesion of neutrophils to P-selectin in a flow chamber showed there were more adhered CuD neutrophils than CuA ones. This effect is probably caused by the increased expression of CD11b that was observed in the current study. Second, the evaluation of neutrophil migration under agarose showed that the CuD neutrophils moved farther than the CuA group in response to IL-8 but not fMLP; this suggests an increased sensitivity to a CD11/CD18-independent signalling pathway. Third, the contractile mechanism of endothelial cells was studied. Elevated F-actin formation in Cu-chelated lung microvascular endothelial cells suggests that neutrophil emigration may be promoted by enhanced cytoskeletal reorganization of the endothelium during copper deficiency. Combined, these results support the theory that dietary copper deficiency has proinflammatory effects on both neutrophils and the microvascular endothelium that promote neutrophil-endothelial interactions.     

Reducing effect of ingesting tannic acid on the absorption of iron, but not of zinc, copper and manganese by rats

Interest in the beneficial effects of polyphenols, including tannic acid (TA), is increasing, although, these compounds also have adverse effects; for example, on the absorption of iron (Fe), and possibly other trace minerals. We examined the effect of a graded dose of TA on the absorption of Fe and compared with that of zinc (Zn), copper (Cu) and manganese (Mn) in rats. We also investigated the effect of TA on cecal fermentation which plays a role in absorption. In Experiment 1, to set the optimum dose of Fe, male Sprague-Dawley rats (weighing 70-90 g) after acclimatization were fed with different levels of dietary Fe (5, 10, 20, 30 and 35 mg/kg). We observed that the hematocrit (Ht), serum Fe concentration and transferrin saturation (%) were each reduced in those rats fed less than 20 mg/kg Fe in a dose-dependent manner. In Experiment 2, the rats were fed with test diets containing the minimum required level of Fe, 30 mg/kg diet, with (5, 10, 15 and 20 g/kg diet) or without TA for a period of three weeks. Feeding a diet containing more than 10 g TA/kg diet, but not 5 g TA/kg diet, reduced the hemoglobin concentration (Hb), Ht and serum Fe concentration due to decreased Fe absorption. In contrast, the Zn, Cu and Mn absorption was not affected by TA feeding. It is also demonstrated that liver Fe, but not the Zn, Cu and Mn contents, were lower in the TA groups than in the TA-free control group. Feeding TA slightly decreased the pH value of the cecal contents with an increase in the major short-chain fatty acid pool. About 15% of the ingested TA were recovered in the feces of each TA-fed group. Our results demonstrate that more than 10 g TA/kg diet induced anemia by reducing the Fe absorption, although there was no effect on the absorption of other important trace minerals. Our findings suggest that the usual intake of polyphenols is relatively safe, but that a high intake by supplementation or by dietary habit of tannin affects only the Fe level.     

Levels of plasma ceruloplasmin protein are markedly lower following dietary copper deficiency in rodents

Ceruloplasmin (Cp) is a multicopper oxidase and the most abundant copper binding protein in vertebrate plasma. Loss of function mutations in humans or experimental deletion in mice result in iron overload consistent with a putative ferroxidase function. Prior work suggested plasma may contain multiple ferroxidases. Studies were conducted in Holtzman rats (Rattus norvegicus), albino mice (Mus musculus), Cp?/? mice, and adult humans (Homo sapiens) to investigate the copper–iron interaction. Dietary copper-deficient (CuD) rats and mice were produced using a modified AIN-76A diet. Results confirmed that o-dianisidine is a better substrate than paraphenylene diamine (PPD) for assessing diamine oxidase activity of Cp. Plasma from CuD rat dams and pups, and CuD and Cp?/? mice contained no detectable Cp diamine oxidase activity. Importantly, no ferroxidase activity was detectable for CuD rats, mice, or Cp?/? mice compared to robust activity for copper-adequate (CuA) rodent controls using western membrane assay. Immunoblot protocols detected major reductions (60–90%) in Cp protein in plasma of CuD rodents but no alteration in liver mRNA levels by qRT-PCR. Data are consistent with apo-Cp being less stable than holo-Cp. Further research is needed to explain normal plasma iron in CuD mice. Reduction in Cp is a sensitive biomarker for copper deficiency.     

Regression of copper-deficient heart hypertrophy: reduction in the size of hypertrophic cardiomyocytes

Dietary copper (Cu) deficiency causes cardiac hypertrophy and its transition to heart failure in a mouse model. Cu repletion results in rapid regression of cardiac hypertrophy and prevention of heart failure. The present study was undertaken to understand dynamic changes of cardiomyocytes in the hypertrophic heart during the regression. Dams of FVB mice were fed a Cu-deficient (CuD) diet (0.3 mg Cu/kg) starting on Day 3 post-delivery, and weanling pups were fed the same diet until Cu repletion (6.0 mg Cu/kg) in the diet at 31 days of age. Heart samples were obtained at the end of CuD feeding or at 3, 7, 14 or 28 days after Cu repletion. Cu deficiency resulted in increases in the size and reduction in the number of cardiomyocytes in the heart. Cu repletion led to regression in the size of hypertrophic cardiomyocytes and normalization of the total number of cardiomyocytes. Although a direct reduction in the cell size would be significantly responsible for the regression of heart hypertrophy, some hypertrophic cardiomyocytes upon Cu repletion reentered the cell cycle as determined by Ki-67 staining in the cardiomyocyte-specific α-sarcomeric actin-stained cells and underwent division as determined by a mitosis-specific marker, phospho-histone 3. Quantitative analysis indicated that the replication of hypertrophic cardiomyocytes made a contribution of about one-third to the total mitosis of the regenerated myocardium. This study suggests that a direct reduction in the size of some hypertrophic cardiomyocytes and a replication of other hypertrophic cardiomyocytes with reduced size make a significant contribution to the regression of CuD heart hypertrophy, leading to normalization of the size and the number of cardiomyocytes in the heart.     

Effects of copper, iron, and ascorbic acid on manganese availability to rats.

Four experiments were done to characterize the interactions of copper, iron, and ascorbic acid with manganese in rats. All experiments were factorially arranged Dietary Mn concentrations were less than 1 micrograms/g (Mn0) and 50 micrograms/g (Mn+). Dietary Cu was less than 1 mg/g (Cu0) and 5 micrograms/g (Cu+); dietary Fe was 10 micrograms/g (Fe10) and 140 micrograms/g (Fe140). Ascorbic acid (Asc) was not added to the diet or added at a concentration of 10 g/kg diet. Experiment 1 had two variables, Mn and Cu; in Experiment 2, the variables were Mn and Asc. In Experiment 3, the variables were Mn, Cu, and Asc; in Experiment 4, they were Mn, Cu, and Fe. Definite interactions between Mn and Cu were observed, but they tended to be less pronounced than interactions between Mn and Fe. Cu depressed absorption of 54Mn and accelerated its turnover. In addition, adequate Cu (Cu+), compared with Cu0, depressed liver, plasma, and whole blood Mn of rats. Absorption of 67Cu was higher in animals fed Mn0 diets than in those fed Mn+. Ascorbic acid depressed Mn superoxide dismutase activity and increased Cu superoxide dismutase activity in the heart. The addition of ascorbic acid to the diet did not affect Mn concentration in the liver or blood. Absorption of 54Mn was depressed in rats fed Fe140 compared with those fed Fe10. Interactions among Fe, Cu, and Mn resulted in a tendency for Mn superoxide dismutase activity to be lower in rats fed Fe140 than in rats fed Fe10. Within the physiologic range of dietary concentrations, Mn and Cu have opposite effects on many factors that tend to balance one another. The effects of ascorbic acid on Mn metabolism are much less pronounced than effects of dietary Cu, which in turn affects Mn metabolism less than does Fe.     

Effect of dimethyl sulfoxide on enlarged hearts of copper-deficient rats

The purpose of this study was to examine, by transmission electron microscopy (TEM), the nature of the protective effect of dimethyl sulfoxide (DMSO) on hearts of copper-deficient (CuD) rats. Male, weanling Sprague-Dawley rats were fed, in a two-way design, CuD (0.45 micrograms/g) or copper-sufficient (CuS, 5.4 micrograms/g) diets with or without 5% DMSO in their drinking water. After 28 d, CuD rats showed typical signs of copper deficiency, including reduced liver and heart Cu, enlarged hearts, and anemia. DMSO-treated, CuD rats had lower heart weights and higher hematocrits than CuD rats. DMSO enhanced organ Cu concentrations in CuS, but not in CuD rats. TEM of CuD hearts showed myofibrillar distortion and enlarged, vacuolated mitochondria with fragmented cristae; morphometric measurements indicated an enhanced mitochondrial/myofibrillar ratio (mito/myo), but an increase of both mitochondrial and myofibrillar mass relative to CuS hearts. Compared to CuD hearts, DMSO-treated CuD hearts showed better mitochondrial morphology and myofibrillar organization, as well as a greater mito/myo, but lower mitochondrial and myofibrillar masses. Its function as a hydroxyl radical scavenger indicates that DMSO could protect CuD hearts, in particular their mitochondria, against oxidative damage. However, because measurements of thiobarbituric acid reactive substances were not consistent with this theory, other metabolic mechanisms, direct and indirect, must be examined.     

Metabolic interactions between lead and copper in rats ingesting lead acetate

The effects of Pb ingestion with and without concurrent dietary Cu supplementation were determined on parameters associated with Cu deficiency in rats fed a nutritionally adequate diet. Groups of weanling male Sprague-Dawley rats were fed a purified (AIN-′76) diet and given Pb (0 or 500 ppm) and Cu (0, 6, or 12 ppm) as the acetate salt in deionized drinking water for 5 wk. A Pb-induced Cu deficiency resulted that was characterized by decreased levels of Cu in tissue and blood, decreased activities of the Cu-dependent enzymes, ceruloplasmin (serum) and Superoxide dismutase (erythocytes), and increased concentration of Fe in liver. These effects of Pb were prevented completely or in part by concurrent Cu supplementation. The Pb-induced decrease in hemoglobin and hematocrit values and the decrease in weight gain were not prevented by Cu supplementation of the diet and can therefore be assumed to be the direct result of a toxic effect of Pb. Although Pb ingestion resulted in decreased concentration of Cu in blood and tissue, additional dietary Cu had no effect on Pb levels.     

Copper modulates sex-specific fructose hepatoxicity in nonalcoholic fatty liver disease (NALFD) Wistar rat models

This study aimed to characterize the impact of dietary copper on the biochemical and hepatic metabolite changes associated with fructose toxicity in a Wistar rat model of fructose-induced liver disease. Twenty-four male and 24 female, 6-week-old, Wister rats were separated into four experimental dietary treatment groups (6 males and 6 females per group), as follows: (1) a control diet: containing no fructose with adequate copper (i.e., CuA/0% Fruct); (2) a diet regimen identical to the control and supplemented with 30% w/v fructose in the animals' drinking water (CuA/30% Fruct); (3) a diet identical to the control diet but deficient in copper content (CuD/0% Fruct) and (4) a diet identical to the control diet but deficient in copper content and supplemented with 30% w/v fructose in the drinking water (CuD/30% Fruct). The animals were fed the four diet regimens for 5 weeks, followed by euthanization and assessment of histology, elemental profiles and identification and quantitation of liver metabolites. Results from ¹H nuclear magnetic resonance metabolomics revealed mechanistic insights into copper modulation of fructose hepatotoxicity through identification of distinct metabolic phenotypes that were highly correlated with diet and sex. This study also identified previously unknown sex-specific responses to both fructose supplementation and restricted copper intake, while the presence of adequate dietary copper promoted most pronounced fructose-induced metabolite changes.     

Limited effects of combined dietary copper deficiency/iron overload on oxidative stress parameters in rat liver and plasma

Copper (Cu) deficiency decreases the activity of Cu-dependent antioxidant enzymes such as Cu,zinc-superoxide dismutase (Cu,Zn-SOD) and may be associated with increased susceptibility to oxidative stress. Iron (Fe) overload represents a dietary oxidative stress relevant to overuse of Fe-containing supplements and to hereditary hemochromatosis. In a study to investigate oxidative stress interactions of dietary Cu deficiency with Fe overload, weanling male Long–Evans rats were fed one of four sucrose-based modified AIN-93G diets formulated to differ in Cu (adequate 6 mg/kg diet vs. deficient 0.5 mg/kg) and Fe (adequate 35 mg/kg vs. overloaded 1500 mg/kg) in a 2×2 factorial design for 4 weeks prior to necropsy. Care was taken to minimize oxidation of the diets prior to feeding to the rats. Liver and plasma Cu content and liver Cu,Zn-SOD activity declined with Cu deficiency and liver Fe increased with Fe overload, confirming the experimental dietary model. Liver thiobarbituric acid reactive substances were significantly elevated with Fe overload (pooled across Cu treatments, 0.80±0.14 vs. 0.54±0.08 nmol/mg protein; P<.0001) and not affected by Cu deficiency. Liver cytosolic protein carbonyl content and the concentrations of several oxidized cholesterol species in liver tissue did not change with these dietary treatments. Plasma protein carbonyl content decreased in Cu-deficient rats and was not influenced by dietary Fe overload. The various substrates (lipid, protein and cholesterol) appeared to differ in their susceptibility to the in vivo oxidative stress induced by dietary Fe overload, but these differences were not exacerbated by Cu deficiency.     

Transferrin and Iron Uptake by the Brain: Effects of Altered Iron Status

Transferrin (Tf) and iron uptake by the brain were measured in rats using 59Fe-125I-Tf and 131I-albumin (to correct for the plasma content of 59Fe and 125I-Tf in the organs). The rats were aged from 15 to 63 days and were fed (a) a low-iron diet (iron-deficient) or, as control, the same diet supplemented with iron, or (b) a chow diet with added carbonyl iron (iron overload), the chow diet alone acting as its control. Iron deficiency was associated with a significant decrease and iron overload with a significant increase in brain nonheme iron concentration relative to the controls. In each dietary treatment group, the uptake of Tf and iron by the brain decreased as the rats aged from 15 to 63 days. Both Tf and iron uptake were significantly greater in the iron-deficient rats than in their controls and lower in the iron-loaded rats than in the corresponding controls. Overall, iron deficiency produced about a doubling and iron overload a halving of the uptake values compared with the controls. In contrast to that in the brain, iron uptake by the femurs did not decrease with age and there was relatively little difference between the different dietary groups. 125I-Tf uptake by the brains of the iron-deficient rats increased very rapidly after injection of the labelled proteins, within 15 min reaching a plateau level which was maintained for at least 6 h. The uptake of 59Fe, however, increased rapidly for 1 h and then more slowly, and in terms of percentage of injected dose reached much higher values than did 125I-Tf uptake.(ABSTRACT TRUNCATED AT 250 WORDS)     

Cu loading alters expression of non-IRE regulated, but not IRE regulated, Fe dependent proteins in HepG2 cells

This paper investigates the extent to which Cu loading influences Fe levels in HepG2 cells and the effect on proteins regulated by Fe status. Cu supplementation increased Cu content 3-fold, concomitant with a decrease in cellular Fe levels. Intracellular levels of both transferrin (Tf) and ceruloplasmin (Cp) protein rose in parallel with increased secretion into the culture media. There was no increase in mRNA levels for either protein. Rather, our data suggested increased translation of the mRNA. The increase was not reflected in total protein synthesis, which actually decreased. The effect was not a generalised stress or cell damage response, since heat shock protein 70 levels and lactate dehydrogenase secretion were not significantly altered. To test whether the Cu effect could be acting though the decrease in Fe levels, we measured transferrin receptor (TfR) levels using ¹²⁵I labeled Tf and mRNA analysis. Neither protein nor mRNA levels were changed. Neither was the level of ferroportin mRNA. As a positive control, Fe chelation increased Tf and Cp secretion significantly, and TfR mRNA levels rose 2-fold. We excluded the possibility that the increased Cp or Tf could provide the required substrate to stimulate Fe efflux, and instead demonstrate that Cu can substitute for Fe in the iron regulatory protein - iron responsive element regulation mechanism.     

Influence of magnesium deficiency on the bioavailability and tissue distribution of iron in the rat

We investigated the effect of dietary magnesium (Mg) deficiency on the nutritive utilization and tissue distribution of iron (Fe). Wistar rats were fed an Mg-deficient diet (56 mg/kg) for 70 days. Absorbed Fe, Fe balance, number of the erythrocytes [red blood cells (RBC)] and leukocytes white blood cells (WBC)], hemoglobin (Hb), and Fe content were determined in samples of plasma, whole blood, skeletal muscle, heart, kidney, liver, spleen, femoral bone, and sternum obtained on experimental days 21, 35, and 70. The Mg-deficient diet significantly increased Fe absorption and Fe balance from week 5 until the end of the experimental period. This effect was accompanied by a significant decrease in the concentration of RBC and Hb from day 35, which caused the decrease in whole blood Fe seen on day 70. However, WBC were significantly increased from day 21 until the end of the experimental period. Mg deficiency significantly increased plasma and liver Fe at all three time points investigated. Spleen, heart, and kidney Fe were significantly increased only at the end of the study. However, on day 70, Fe concentration in the sternum had decreased significantly. No changes were found in skeletal muscle or femur Fe content. Mg deficiency led to increased intestinal absorption of Fe and decreased RBC counts, possibly as a result of increased fragility of the erythrocytes. Intestinal interactions between Fe and Mg, together with activation of erythropoiesis as a result of hemolysis, favored intestinal absorption of Fe. This situation gave rise to an increase in plasma Fe levels, which in turn favored Fe uptake and storage by different organs, especially the liver and spleen. However, despite the increased Fe content seen in the tissues of rats fed the Mg-deficient diet, these animals were unable to compensate for the hemolysis caused by this nutritional deficiency.     

l-Lysine supplementation does not affect the bioavailability of copper or iron in rats

l-lysine (Lys) is an essential amino acid that is added to foods and dietary supplements. Lys may interact with mineral nutrients and affect their metabolism. This study examined the effect of dietary Lys supplementation on the bioavailability of copper (Cu) and iron (Fe). Weanling male Sprague-Dawley rats were fed one of five diets (20% casein) for 4 weeks containing normal Cu and Fe (control) or low Cu or Fe without (LCu, LFe) or with (LCu + Lys, LFe + Lys) addition of 1.5% Lys. Final body weights, body weight gains and food consumption of the rats did not differ (P ≥ 0.05) among diet groups. Rats fed the low Cu or Fe diets showed changes in nutritional biomarkers compared to control rats, demonstrating reduced Cu and Fe status, respectively. Hematological parameters, serum ceruloplasmin activity and Cu and Fe concentrations in serum, liver, kidney and intestinal mucosa were unaffected (P ≥ 0.05) by Lys supplementation. These results indicate that in the context of an adequate protein diet, Lys supplementation at a relatively high level does not affect Cu or Fe bioavailability in rats.     

Alterations of serum selenium, zinc, copper, and iron concentrations and some related antioxidant enzyme activities in patients with cutaneous leishmaniasis

The aim of this study was to measure the alterations in serum selenium (Se), copper (Cu), zinc (Zn), and iron (Fe) concentrations and their carrier proteins, ceruloplasmin (Cp), transferrin (Tf) albumin, and related antioxidant enzyme activities, erythrocyte Cu-Zn Superoxide dismutase (Cu-Zn SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) activities in patients with cutaneous leishmaniasis (CL). Erythrocyte Cu-Zn SOD activities, serum Cu concentrations, and Cp levels were found to be significantly higher in the patients group than those of controls. However, GSH-Px and CAT activities and Se, Zn, Fe, and Tf levels were lower in patients than in the control subjects. There were positive important correlation’s between Cu-Zn SOD and Cp, Cu-Zn SOD and Cu, Cp and Cu, GSH-Px and Se, and Fe and CAT in the patients group. Our results showed that serum essential trace elements Se, Zn, Cu, and Fe concentrations and their related enzymes Cu-Zn SOD, GSH-Px, and CAT activities change in CL patients. The changes may be a part of defense strategies of organism and are induced by the hormonelike substances.     

Effects of iron deficiency upon the antibody response to influenza virus in rats

The effects of severe and moderate iron deficiency upon the antibody response to influenza virus were investigated in rats. Three groups of weanling male Wistar rats were fed one of two iron-deficient diets (5 mg and 15 mg iron/kg diet) or a normal iron-containing diet (35 mg iron/kg diet). A group of individually pair-fed rats was introduced with the low iron-consuming rats. The effects of the diets upon various iron status parameters were followed during the 4th, 5th, 6th, and 7th week of diet. After 4 weeks of feeding different diets, an intraperitoneal injection of inactivated influenza virus A/New Jersey/76 was performed and a recall injection was done at 5 weeks. Primary and secondary antibody responses were assayed. Rats were sacrificed at 7 weeks of diet. After 4 weeks of feeding different diets, the rats fed the 5 mg iron/kg diet were severely anemic and rats fed 15 mg iron/kg diet were moderately iron-deficient, as shown by their iron status parameters. Growth was delayed in anemic and matched pair-fed rats. A primary antibody response was almost nonexistent in all groups. Secondary antibody titers were significantly weaker in anemic rats than in ad libitum controls, but were not different from those of pair-fed rats. This response was similar in moderately iron-deficient, ad libitum, and pair-fed rats. These results show that antibody synthesis in response to the influenza virus vaccine is preserved in moderate iron deficiency but is reduced in severe anemia. The reduction in energy consumption associated with severe iron deficiency in the rat could play a part in the altered humoral response.