Chronic ethanol feeding inhibits plasma levels of insulin-like growth factor-1

The purpose of this study was to determine whether the generalized catabolic effects of chronic ethanol may be associated with a decline in plasma levels of insulin-like growth factor-1 (IGF-1). Male Sprague-Dawley rats were fed a liquid diet containing 5% ethanol or pair-fed a diet made isocaloric with maltose-dextrin. Animals were maintained on this diet for either 12 days or 4.5 months. Another group of animals were fed control diet ad libitum for 2 weeks. After 12 days of feeding, plasma concentrations of IGF-1 in ad libitum fed rats were 771 +/- 41 ng/ml which was greater than concentrations in either pair-fed (595 +/- 23 ng/ml) or ethanol-fed (680 +/- 40 ng/ml) rats (P less than 0.05). After 4.5 months of feeding, plasma levels of IGF-1 in ad libitum and pair-fed rats were similar to the 12 day study (736 +/- 56 and 607 +/- 26 ng/ml, respectively). However, a significant decrease in plasma levels of IGF-1 was observed in ethanol-fed animals over the 4.5 month period (551 +/- 28 ng/ml, P less than 0.05). Results of a similar study in rats fed a high-fat diet for 4.5 months were similar to those found with the low-fat diet. These results indicate that 1) dietary restriction of the type routinely used in this pair-feeding regimen decreases plasma levels of IGF-1, 2) chronic ethanol feeding further decreases plasma IGF-1 levels compared to pair-fed rats, 3) the effects of ethanol on IGF-1 concentrations are not modified by dietary fat, and 4) the effects on IGF-1 are not directly dependent on elevated plasma ethanol concentrations. Our results suggest that IGF-1 secreting cells in the liver may be progressively damaged by chronic ethanol feeding.     

Iron overload of the bone marrow by trimethylhexanoyl-ferrocene in rats.

Iron-deficient female Wistar rats were fed a diet which contained 0.5% 3,5,5-trimethylhexanoyl (TMH)-ferrocene over a 57-week period. The state of iron deficiency was characterized by means of the absence of stainable iron in the bone marrow. After the first days on the iron-enriched diet, ferritin-containing siderosomes were found, in numerous erythroblasts up to orthochromatic normoblasts and in reticulocytes, i.e. the dispensed iron was used for haemoglobin synthesis. After 1 week the first macrophages showed a positive Perls' Prussian blue reaction. In the cytoplasm they stored the iron in the form of free ferritin molecules and lysosomally as aggregated ferritin and/or haemosiderin. The iron loading of the macrophages increased in both of the storage qualities proportionally with duration of the feeding period and reached a maximum after 38 weeks. Final stages showed extremely iron-loaded macrophages with high concentrations of free ferritin molecules and large siderosomes, partially flowing together to still greater units. Iron deposits within endothelial cells of bone marrow sinusoids can be observed for the first time after 4 weeks. In these cells the iron is stored as ferritin in siderosomes of relatively small and uniform size; free ferritin molecules in the cytosol were of only slight concentration. The TMH-ferrocene model of iron overload shows in the bone marrow: (1) an unimpeded utilization of the iron component for erythropoiesis, (2) development of excessive iron overload of the bone marrow in macrophages and endothelial cells of sinusoids and (3) a pattern of distribution of iron as seen in secondary haemochromatosis.     

The effects of resistance exercise and post-exercise meal timing on the iron status in iron-deficient rats

Resistance exercise increases heme synthesis in the bone marrow and the hemoglobin in iron-deficient rats. Post-exercise early nutrient provision facilitates skeletal muscle protein synthesis compared to late provision. However, the effects of post-exercise nutrition timing on hemoglobin synthesis are unclear. The current study investigated the effect of post-exercise meal timing on the activity of the key enzyme involved in hemoglobin synthesis, δ-aminolevulinic acid dehydratase (ALAD), in the bone marrow and examined the hemoglobin concentration in iron-deficient rats. Male 4-week-old Sprague-Dawley rats were fed an iron-deficient diet containing 12 mg iron/kg and performed climbing exercise (5 min × 6 sets/day, 3 days/week) for 3 weeks. The rats were divided into a group fed a post-exercise meal early after exercise (E) or a group fed the meal 4 h after exercise (L). A single bout of exercise performed after the 3-week training period increased the bone marrow ALAD activity, plasma iron concentration, and transferrin saturation. Although the plasma iron concentration and transferrin saturation were lower in the E group than the L group after a single bout of exercise, the basal hematocrit, hemoglobin, and TIBC after 3 weeks did not differ between the groups. Therefore, resistance exercise increases the bone marrow ALAD activity, while the post-exercise meal timing has no effect on the hemoglobin concentration in iron-deficient rats.     

The impact of iron content in a diet high in fat,fructose, and salt on metabolic state and mineral status of rats

The purpose of the study was to assess the influence of dietary iron content on lipid and carbohydrate metabolism and on zinc and copper status in rats fed with a diet high in fat, fructose, and salt. Wistar rats were fed with diets high in fat, fructose, and salt, containing differing amounts of iron, namely, deficit, normal, and high levels. After 6 weeks, the animals were weighed and killed. The liver, heart, and pancreas were collected, as were blood samples. The total cholesterol, triglycerides, fasting glucose, and insulin levels in the serum were measured. The iron, zinc, and copper concentrations in tissues and serum were determined. It was found that in rats fed with the iron-deficit diet, cholesterol and glucose profiles improved. Both deficit and excess iron in the diet decreased insulin concentration in rats and disturbed iron, zinc, and copper status. High-iron level in the diet decreased the relative mass of the pancreas. In conclusion, the decrease in serum insulin concentration observed in rats fed with the modified diet high in iron was associated with iron and copper status disorders, and also, with a relatively diminished pancreas mass. A deficit of iron in the diet improved lipid and carbohydrate metabolism in rats.     

Comparative Effects of Ethanol and Malnutrition on the Development of Catecholamine Neurons: Changes in Neurotransmitter Levels

Abstract: The comparative effects of exposure to ethanol and malnutrition on the concentrations of tyrosine and catecholamines in whole brain and selected regions of brain have been studied in the developing rat. These animals were the offspring of optimally nourished rats (control pups), of rats fed a diet with 35% of the calories supplied by ethanol (ETOH pups), or of animals fed a diet calorically equivalent to the latter but lacking ethanol (iso-caloric, 1C pups). These diets were administered to dams either during the last week of gestation (prenatal) or during lactation (postnatal). Tyrosine levels were elevated prior to birth in the prenatal ETOH or IC pups or at 1 and 2 weeks of age in postnatal ETOH or 1C pups as compared with values found in the control offspring. Dopamine concentration in whole brain was significantly lower in prenatal ETOH pups than in prenatal IC pups at 3 weeks of age. Levels in the brains of postnatal ETOH pups were lower than control values, but not relative to animals exposed to 1C diet. Investigation of corpus striatum showed a significant decrease in dopamine concentration compared with control or IC pup values as a result of postnatal exposure to ethanol. Norepinephrine levels in the whole brain of prenatal ETOH pups were consistently 30–40% lower than either control or matched 1C pups during development. At 3 weeks of age, the norepinephrine levels in the hypothalamus of animals exposed to ethanol pre or postnatally were 30–60% lower than values in the corresponding region in either control or 1C pups. In the rat model described, ethanol caused a decrease in catecholamine levels, perhaps solely by affecting the norepinephrine neurons.     

Serum ferritin, iron and transferrin in women with thyrotoxic Graves' disease before and after methimazole treatment

We investigated iron metabolism in 47 women with thyrotoxic Graves' disease. Serum iron, ferritin, transferrin, triiodothyronine and thyroxine concentrations were RIA measured before and after methimazole treatment when patients became euthyroid. The control group consisted of 52 healthy women. We noted that serum ferritin levels and the ferritin to transferrin ration were significantly lower while the iron to ferritin ratio was higher in patients before and after methimazole therapy. Iron concentration as well as the iron to transferrin and the iron to thyroid hormone ratios were decreased only before treatment.     

Iron Excess Disturbs Metabolic Status and Relative Gonad Mass in Rats on High Fat, Fructose, and Salt Diets

The aim of this study was to assess the metabolic and physiological changes in rats fed a diet high in fat, fructose, and salt, and with excess iron level. Mineral status was also estimated. Wistar rats were assigned to groups fed either a standard control diet (C) or a diet high in fat, fructose, and salt. The noncontrol diets contained either normal (M) or high level (MFe) of iron. After 6 weeks, the length and weight of the rats were measured, and the animals were euthanized. The kidneys and gonads were collected, and blood samples were taken. Serum levels of insulin, nitric oxide, and iron were measured. The iron, zinc, copper, and calcium concentrations of tissues were determined. It was found that the M diet led to a significant increase in the relative kidney mass of the rats compared with the control group. Among the rats fed the M diet, markedly higher serum level of iron and lower levels of zinc and copper were observed in tissues, while significantly higher calcium levels were found in the gonads. The MFe diet resulted in decreased obesity index, insulin level, and nitric oxide serum concentration in the rats, when compared with both the M and C diets. The high iron level in the modified diet increased the relative mass of the gonads. The excess iron level in the diet disturbed the zinc, copper, and calcium status of tissues. The decrease in insulin and nitric oxide in rats fed the diet high in iron, fat, fructose, and salt was associated with disorders of zinc, copper, and calcium status, as well as with an increase in the relative mass of the gonads.     

Changes in transferrin during the red cell replacement in amphibia

Transferrin, a plasma glycoprotein, carries iron from storage sites to immature erythroid cells for hemoglobin synthesis. The replacement of larval red cells by adult red cells, which occurs during metamorphosis in bullfrogs, requires extensive formation of hemoglobin and new red cells. Large changes in red cell iron storage also occur during the red cell replacement. Both the concentration and the level of iron saturation of plasma transferrin were measured during metamorphosis to determine if there were changes in plasma transferrin which coincided with the changes in red cell iron storage and ferritin content. Plasma transferrin concentrations increased from 0.96 to 2.6 mg/ml during the period when red cell storage iron and ferritin decreased. Plasma iron concentrations also increased when the transferrin concentration increased, suggesting that the additional transferrin may be involved in moving iron from the larval red cell stores. At the end of metamorphosis, the plasma iron concentration decreased to premetamorphic levels but the transferrin concentration remained high, resulting in a decrease in saturation to 18% compared to 45% in the larvae. In addition to differences in iron saturation, adult transferrin had different electrophoretic properties from larval transferrin. The results support the hypotheses that during early ontogeny plasma transferrin and red cell iron storage are coordinated to provide iron for the formation of the first generation of adult red cells and that transferrin may participate in the control of red cell ferritin synthesis.     

The effect of copper deficiency on the formation of hemosiderin in sprague-dawley rats

We demonstrated previously that loading iron into ferritin via its own ferroxidase activity resulted in damage to the ferritin while ferritin loaded by ceruloplasmin, a copper-containing ferroxidase, was not damaged and had similar characteristics to native ferritin (Welch et al. (2001) Free Radic Biol Med 31:999–1006). Interestingly, it has been suggested that the formation of hemosiderin, a proposed degradation product of ferritin, is increased in animals deficient in copper. In this study, groups of rats were fed normal diets, copper deficient diets, iron supplemented diets, or copper deficient-iron supplemented diets for 60 days. Rats fed copper-deficient diets had no detectable active serum ceruloplasmin, which indicates that they were functionally copper deficient. There was a significant increase in the amount of iron in isolated hemosiderin fractions from the livers of copper-deficient rats, even more than that found in rats fed only an iron-supplemented diet. Histological analysis showed that copper-deficient rats had iron deposits (which are indicative of hemosiderin) in their hepatocytes and Kupffer cells, whereas rats fed diets sufficient in copper only had iron deposits in their Kupffer cells. Histologic evidence of iron deposition was more pronounced in rats fed diets that were deficient in copper. Additionally, sucrose density-gradient sedimentation profiles of ferritin loaded with iron in vitro via its own ferroxidase activity was found to have similarities to that of the sedimentation profile of the hemosiderin fraction from rat livers. The implications of these data for the possible mechanism of hemosiderin formation are discussed.     

Effect of dietary iron deficiency on mineral levels in tissues of rats

To clarify the influence of iron deficiency on mineral status, the following two synthetic diets were fed to male Wistar rats: a control diet containing 128 micrograms iron/g, and an iron-deficient diet containing 5.9 micrograms iron/g. The rats fed the iron-deficient diet showed pale red conjunctiva and less reactiveness than the rats fed the control diet. The hemoglobin concentration and hematocrit of the rats fed the iron-deficient diet were markedly less than the rats fed the control diet. The changes of mineral concentrations observed in tissues of the rats fed the iron-deficient diet, as compared with the rats fed the control diet, are summarized as follows: . Iron concentrations in blood, brain, lung, heart, liver, spleen, kidney, testis, femoral muscle, and tibia decreased; . Calcium concentrations in blood and liver increased; calcium concentration in lung decreased; . Magnesium concentration in blood increased; . Copper concentrations in blood, liver, spleen and tibia increased; copper concentration in femoral muscle decreased; . Zinc concentration in blood decreased; . Manganese concentrations in brain, heart, kidney, testis, femoral muscle and tibia increased. These results suggest that iron deficiency affects mineral status (iron, calcium, magnesium, copper, zinc, and manganese) in rats.     

Vitamin A deficiency modulates iron metabolism via ineffective erythropoiesis

Vitamin A modulates inflammatory status, iron metabolism and erythropoiesis. Given that these factors modulate the expression of the hormone hepcidin (Hamp), we investigated the effect of vitamin A deficiency on molecular biomarkers of iron metabolism, the inflammatory response and the erythropoietic system. Five groups of male Wistar rats were treated: control (AIN-93G), the vitamin A-deficient (VAD) diet, the iron-deficient (FeD) diet, the vitamin A- and iron-deficient (VAFeD) diet or the diet with 12 mg atRA/kg diet replacing all-trans-retinyl palmitate by all-trans retinoic acid (atRA). Vitamin A deficiency reduced serum iron and transferrin saturation levels, increased spleen iron concentrations, reduced hepatic Hamp and kidney erythropoietin messenger RNA (mRNA) levels and up-regulated hepatic and spleen heme oxygenase-1 gene expression while reducing the liver HO-1 specific activity compared with the control. The FeD and VAFeD rats exhibited lower levels of serum iron and transferrin saturation, lower iron concentrations in tissues and lower hepatic Hamp mRNA levels compared with the control. The treatment with atRA resulted in lower serum iron and transferrin concentrations, an increased iron concentration in the liver, a decreased iron concentration in the spleen and in the gut, and decreased hepatic Hamp mRNA levels. In summary, these findings suggest that vitamin A deficiency leads to ineffective erythropoiesis by the down-regulation of renal erythropoietin expression in the kidney, resulting in erythrocyte malformation and the consequent accumulation of the heme group in the spleen. Vitamin A deficiency indirectly modulates systemic iron homeostasis by enhancing erythrophagocytosis of undifferentiated erythrocytes.     

Conflicting effects of BMI and waist circumference on iron status

The association between obesity and iron status has a long history and is still receiving attention. However comparative analysis of the association between general obesity (BMI) and visceral obesity (waist circumference) with iron status has not been extensively researched. The aim of the present study is thus to determine if body mass index and waist circumference have the same correlation with iron status. One thousand one hundred and thirty people (225 men and 905 women) aged 30 years and above participated in this study. Anthropometric parameters, haemoglobin, iron and total iron binding capacity concentrations were measured using standard methods. Percentage transferrin saturation was calculated and ferritin concentrations were measured using an enzyme linked immunosorbent assay. Obese or overweight women had significantly lower iron and transferrin saturation concentration when compared to non-obese women. In contrast, women with high waist circumference had comparable plasma iron and transferrin saturation to women with normal waist circumference. Partial correlation analysis and linear regression analysis showed that BMI is negatively and significantly associated with plasma iron, transferrin saturation, Hb and ferritin concentration, whilst waist circumference is positively but insignificantly associated with plasma iron, transferrin saturation, Hb and ferritin concentration. Binary regression analysis showed that obese or overweight people are more likely to have iron deficiency, whilst those with raised waist circumference are more likely to have iron overload. Multivariate analysis showed that body mass index is negatively and significantly associated with low iron status, while waist circumference is positively and insignificantly associated with iron status. This is supported by a comparison of plasma iron, transferrin saturation and ferritin concentrations in participants with high body mass index and normal waist circumference and participants with normal body mass index and high waist circumference to those participants having normal body mass index and normal waist circumference. The present study suggests that in women body mass index is associated with low plasma iron, transferrin saturation and ferritin concentrations, while waist circumference is associated with high plasma iron, transferrin saturation and ferritin concentrations.     

Influence of experimental diets on cholesterol and triglyceride levels of rabbit blood serum lipoproteins

Groups of rabbits were fed for six weeks various diets: standard died + ethanol, high-cholesterol diet and a high-cholesterol + ethanol one. During the next six weeks every diet was supplemented with a fresh vegetable (carrot). Cholesterol and triglycerides were determined in the whole serum and in lipoprotein fractions. In rabbits fed standard diet ethanol caused a moderate elevation of VLDL cholesterol and triglyceride and LDL cholesterol levels. In animals on high-cholesterol diet cholesterol and triglyceride concentrations in these fractions were very high. Simultaneous consumption of large amounts of cholesterol and of ethanol resulted in a greater rise of cholesterol concentration in the whole serum and in VLDL and LDL fraction than did high-cholesterol diet alone. Addition of carrot caused a pronounced reduction of serum cholesterol concentration in animals fed all kinds of diets. The reduction concerned mainly VLDL.     

Melatonin controls oxidative stress and modulates iron, ferritin, and transferrin levels in adriamycin treated rats

AIM: Chemotherapy with adriamycin (ADR) is limited by its iron-mediated pro-oxidant toxicity. Because melatonin (MLT) is a broad spectrum antioxidant, we investigated the ability of MLT to control iron, its binding proteins, and the oxidative damage induced by ADR. MAIN METHODS: ADR was given as single i.p. dose of 10 mg kg(-1) body weight into male rats. MLT at a dose of 15 mg kg(-1) was injected daily for 5 days before ADR treatment followed by another injection for 5 days. Biochemical methods were used for this investigation. KEY FINDINGS: ADR injection caused elevations in plasma creatine kinase isoenzyme, lactic dehydrogenase, and aminotransferases, iron, ferritin, and transferrin. These changes were associated with increases in lipid peroxidation and protein oxidation as well as decreases in glutathione (GSH) levels and glutathione-S-transferase (GST) activity, while glutathione peroxidase (GSH-Px), and catalase (CAT) activity were elevated in the heart and liver of ADR treated rats. In the MLT+ADR group, the cardiac and hepatic function parameters and the levels of iron, transferrin and ferritin in plasma were normalized to control levels. The rats that were subjected to MLT+ADR had normalized CAT and GSH-Px activity and decreased TBARS and protein carbonyl levels compared the group only treated with ADR. GST activity and GSH concentration in the heart and liver were normalized when MLT accompanied ADR treatment. SIGNIFICANCE: MLT ameliorated oxidative stress by controlling iron, and binding protein levels in ADR treated rats demonstrating the usefulness of adriamycin in cancer chemotherapy and allowing a better management of iron levels.     

Prenatal and postnatal changes in the content and species of ferritin in rat liver

The iron and ferritin content of rat liver and the species of ferritin present were examined from 4 days before to 3 weeks after birth. 1. Total iron and ferritin iron accumulated rapidly during the last days of gestation and from the second postnatal day underwent a steady depletion. 2. The amount of iron deposited before birth in the liver of each pup varied inversely with litter size and could be increased moderately by injection of iron into the mother before mating. 3. Intraperitoneal injection of iron 1 day after birth doubled the concentration of total iron, ferritin iron and ferritin protein in the liver over the next 24h, but at 3 weeks after birth it raised the very low concentrations of iron and ferritin severalfold. 4. As shown by electrophoretic migration, ferritin and dissociated ferritin subunits prepared from the livers of rats from 4 days before to 3 weeks after birth differed from those of adult liver ferritin and were indistinguishable from those of adult kidney and spleen ferritin. Treatment with iron at 3 weeks of age induced formation of a ferritin with electrophoretic properties resembling those of adult liver. It is concluded that iron given at this stage of development may activate the genetic cistron for adult liver ferritin.     

The effect of copper excess on iron metabolism in sheep.

Sheep were treated with large amounts of copper (20 mg of CuSO4,5H2O/kg body wt. per day) for 9 weeks to examine the effect of copper excess on iron metabolism. In addition to confirming that massive haemolysis and accumulation of copper occurs in the liver, kidney and plasma after 7 weeks of exposure to excess copper, it was observed that excess copper produced an increased plasma iron concentration and transferrin saturation within 1 week. Further, iron preferentially accumulated in the spleen between 4 and 6 weeks of copper treatment, producing 3-fold increases in the iron content of both the ferritin and non-ferritin fractions. A 3-4 fold increase was also observed in the amount of ferritin that could be isolated from the spleen. The copper treatment had little or no effect on the concentration of iron in the liver and bone marrow. The following properties of erythrocytes were also unaffected by copper treatment: size, haemoglobin content and pyruvate kinase activity, although the erythrocyte concentration of copper increased after 6 weeks. Copper accumulated in the spleen between 6 and 9 weeks, probably owing to the phagocytosis of erythrocytes containing high concentrations of copper. The data suggest that copper excess influences iron metabolism, initially by causing a compensated haemolytic anaemia, and later by interfering with re-utilization of iron from ferritin in the reticuloendothelial cells of the spleen.     

The Ratio of sTfR/Ferritin is Associated with the Expression Level of TfR in Rat Bone Marrow Cells After Endurance Exercise

Currently, it is unclear which index of haematological parameters could be used to most easily monitor iron deficiency during endurance training. To address this question, 16 male Wistar rats were randomly assigned to two groups: a sedentary group (n = 8) and an exercised group (n = 8). Initially, animals in the exercise group started running on a treadmill at a rate of 30 m/min, on a 0% grade, for 1 min/session. Running time was gradually increased by 2 min/day. The training plan was one session per day during the initial 2 weeks and two sessions per day during the third to ninth week. At the end of the 9-week experiment, we analysed the blood of the experimental animals for haemoglobin levels, erythrocyte numbers, haematocrit, serum iron levels, total iron binding capacity, transferrin saturation, serum ferritin levels and soluble transferrin receptor (sTfR) levels, and we calculated the ratio of sTfR/ferritin. Erythrocyte numbers, haemoglobin levels and haematocrit values were decreased after 9 weeks of exercise, but sTfR and sTfR/ferritin values were increased (P < 0.01 or P < 0.05). The training regime significantly increased TfR mRNA levels in the bone marrow cells of the exercised rats compared with the sedentary group (1.8 ± 0.5 vs. 1.1 ± 0.2, P < 0.01). These results revealed a significant correlation between TfR levels in the bone marrow cells and the ratio of sTfR/ferritin (r = 0.517; P < 0.01) and sTfR levels (r = 0.206; P < 0.05) in sedentary and exercised rats. In conclusion, we show that sTfR indices and the ratio of sTfR/ferritin could be useful indicators for monitoring iron deficiency during endurance training.     

High Fat Diet Induces Liver Steatosis and Early Dysregulation of Iron Metabolism in Rats

This paper is dedicated to the memory of our wonderful colleague Professor Alfredo Colonna, who passed away the same day of its acceptance. Fatty liver accumulation, inflammatory process and insulin resistance appear to be crucial in non-alcoholic fatty liver disease (NAFLD), nevertheless emerging findings pointed an important role also for iron overload. Here, we investigate the molecular mechanisms of hepatic iron metabolism in the onset of steatosis to understand whether its impairment could be an early event of liver inflammatory injury. Rats were fed with control diet or high fat diet (HFD) for 5 or 8 weeks, after which liver morphology, serum lipid profile, transaminases levels and hepatic iron content (HIC), were evaluated. In liver of HFD fed animals an increased time-dependent activity of iron regulatory protein 1 (IRP1) was evidenced, associated with the increase in transferrin receptor-1 (TfR1) expression and ferritin down-regulation. Moreover, ferroportin (FPN-1), the main protein involved in iron export, was down-regulated accordingly with hepcidin increase. These findings were indicative of an increased iron content into hepatocytes, which leads to an increase of harmful free-iron also related to the reduction of hepatic ferritin content. The progressive inflammatory damage was evidenced by the increase of hepatic TNF-α, IL-6 and leptin, in parallel to increased iron content and oxidative stress. The major finding that emerged of this study is the impairment of iron homeostasis in the ongoing and sustaining of liver steatosis, suggesting a strong link between iron metabolism unbalance, inflammatory damage and progression of disease.