Iron status in the acute phase and six weeks after myocardial infarction

In a case-control study of 84 myocardial infarction patients and 84 population controls we investigated the association between iron status parameters and myocardial infarction during the acute phase and after six weeks. Immediately after the infarction mean ferritin levels were significantly higher, whereas iron levels and iron saturation of transferrin were significantly lower in cases than in controls. Six weeks after the infarction, serum iron levels were still significantly lower in cases than in controls. Neither serum ferritin levels nor serum iron levels did show a clear association with the size of the ischemic tissue damage as estimated by creatine phosphokinase levels. Our results indicate that serum ferritin and iron levels are influenced by the traumatic effects of the myocardial infarction. Possibly, these transient changes are an acute effect, as seen in infections. An increased uptake of iron in the reticulo-endothelial system for synthesis of ferritin, may account for the lowered serum iron level and the iron saturation of transferrin.     

Erythrocyte ferritin content in idiopathic haemochromatosis and alcoholic liver disease with iron overload.

The erythrocyte ferritin content was measured in patients with either idiopathic haemochromatosis or alcoholic liver disease and iron overload to define its value as a marker for an excess of tissue iron. The mean erythrocyte ferritin content in patients with untreated idiopathic haemochromatosis was increased 60-fold and fell with phlebotomy. After phlebotomy many patients had an increased red cell ferritin content despite normal serum ferritin concentrations. That this reflected persistent iron overload with inadequate phlebotomy was suggested by the higher serum iron concentrations, percentage transferrin saturation, and urinary excretion of iron after administration of desferrioxamine, together with a lower annual iron loss by phlebotomy in this group compared with patients with treated disease and normal red cell ferritin content. The mean erythrocyte ferritin content in patients with alcoholic liver disease and iron overload was increased only sevenfold, and the ratio of erythrocyte to serum ferritin clearly discriminated these patients from those with idiopathic haemochromatosis. The determination of erythrocyte ferritin content is a useful non-invasive test for diagnosing idiopathic haemochromatosis, monitoring the effect of phlebotomy in this disorder, and distinguishing patients with this disorder from those with alcoholic liver disease with iron overload.     

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.     

Isolation and purification of duck liver ferritin

A rapid method of purifying duck liver ferritin using high speed centrifugation and chromatography on Sephadex G-200 and Sepharose 6B is described. Protein and iron concentration for each step of purification is given. This method yields 0.12 mg of pure ferritin per gram of wet tissue.     

Serum ferritin in iron overload

Even with uncomplicated iron overload, serum ferritin which can be identified in the circulating blood by sensitive immunochemical methods has a direct and quantitative correlation to the iron stored in the organism. The relation of stored iron and serum ferritin is not linear, but has an exponential character. The diagnostic function of serum ferritin as an indicator of stored iron, however, is virtually not influenced by it. The indications listed in Tab. 3 can be demarcated for diagnostic application in cases of iron overload. Hitherto, the molecular microheterogenicity of serum ferritin has exercised no essential impact on its diagnostic application. High ferritin concentrations may arise in the circulating blood by a number of disease processes listed in Tab. 4, without the simultaneous existence of a respective iron overload of the tissue. These correlations have to be observed in the diagnostic application of determining serum ferritin as well as in methodical possibilities of fault (high dose hook effect), thus limiting the use of serum ferritin as an indicator of stored iron both in case of iron overload and iron deficiency. As in all isolated laboratory investigations, all other clinical and chemical laboratory information available about the individual patient has to be taken into account in each case for interpreting the serum ferritin concentration.     

Iron concentrations in intestinal cancer tissue and in colon and rectum polyps

A prospective randomized trial was used to determine iron concentrations in intestinal cancer tissue and colorectum polyps. We investigated the possible difference between the concentrations of iron, ferritin, albumin, and hemoglobin in the serum of patients with colorectal cancer and polyps. We also determined the relationship between the iron and ferritin levels in cancer tissue, the localization of neoplasms, and the stage of their development. The study comprises 67 patients with colorectum cancer and 42 patients with colon and rectum polyps. The metal was determined by using the total-reflection X-ray fluorescence (TRXRF) method. The mean concentration of iron in colorectal cancer equaled 46.1 μg/g of the tissue and was higher than in the case of polyps (43.2 μg/g). The mean serum iron level in patients with colorectal cancer was statistically lower than in the serum of patients with polyp and in the control group (54.5, 91.3, and 108.0 μg/g, respectively). The determined average concentration of ferritin in the serum of patients with colorectal cancer equaled 60.4 μg/g and was statistically lower than the level of this enzyme in the serum of patients with polyps (85.2 μg/g) and in the control group (102.0 μg/g). There was no difference between the serum albumin and hemoglobin concentrations in patients with colorectal cancer, polyps, and the control. There was no difference in the levels of iron and ferritin depending on the location of the neoplasm and the stage of its development. Also, there was no difference between the concentrations of iron in the cancer tissue of malignant and benign tumors after taking into consideration sex and age of patients. During the examination we determined significantly higher concentrations of iron in the cancer tissue and not in the polyp. The low levels of iron in the serum of patients with malignant tumor may increase colorectal cancer risk.     

Accumulation of storage iron in patients treated for iron-deficiency anaemia.

The repletion of iron stores after treatment was studied in 38 patients with uncomplicated iron-deficiency anaemia. The serum ferritin concentration rose significantly when oral treatment was continued for two months after the attainment of a normal haemoglobin concentration. Patients treated with a total-dose infusion of iron dextran had thehighest final serum levels, which were significantly greater than in patients given Ferro-Gradumet. Oral ferrous sulphate was almost as effective as parenteral iron in producing iron stores.     

The etiological relation between serum iron level and infection incidence in hemodialysis uremic patients

Through the treatment of anaemia in dialysis patients part of the iron ions remain free in the serum which is at the bacterias disposal for growth and the strengthening of their virulence. The linear relation of the increased serum iron level and tissue iron stores in the body and the infection incidence in dialysed patients has become more emphasised. The need of a clearly defined upper threshold of the serum iron concentration limit has been mentioned in scientific journals intensely, and consequently the demand for more precise professional instructions for anaemia treatment. For the purpose of participating in these professional and scientific discussions, we have observed the relation between the iron overload of the organism and complication incidence in 120 of our haemodialysis uremic patients, with special emphasis on infections. It has been established that the sepses incidence is much higher in patients with a serum ferritin concentration above 500 microg/L, than in those patients with a ferritin level lower than the mentioned value ( 2 = 7.857, p = 0.005). The incidence of vascular access infection is significantly higher in those patients with a serum ferritin level above 500 microg/L than in those patients with a ferritin level lower than the mentioned value (Chi2 = 23.186, p = 0.001). Furthermore, it has been determined that the incidence of total infection in patients is 3.8 episodes per 100 patients months, which is in accordance to the referral values of other authors. CONCLUSION--In the analysis of the achieved results, it has been determined that the infection incidence is significantly higher in dialysed patients with a serum iron level higher than 500 g/L, than in those patients with lower values.     

Differential effects of iron and inflammation on ferritin synthesis on free and membrane-bound polyribosomes of rat liver.

We have examined the distribution of ferritin mRNA to free and endoplasmic reticulum (ER)-bound liver polyribosomes during inflammation and iron treatment of rats. Postnuclear tissue supernatants were fractionated on a discontinuous sucrose gradient developed to separate free and bound polyribosomes. Total RNA recovered averaged 3.2 mg/g tissue, 40% of which was with ER and 30% with the free polyribosomes, about 25% being with the postribosomal/RNP fraction. Slot-blot hybridization of equal portions of RNA revealed that 12 h after injection of turpentine to induce inflammation, ferritin mRNA was concentrated on the ER-bound polyribosomes, while it was concentrated on the free polyribosomes 2 h after injection of ferric ammonium citrate. Differences were highly significant, based on multiple determinations and densitometry. Profiles of ferritin mRNA distribution on linear sucrose gradients corroborated the differential findings. Concentrations of total ferritin mRNA per gram liver doubled with iron treatment but were not significantly different 12 h after turpentine treatment. At the same time point after turpentine, ferritin protein synthesis was increased twofold, as measured by the 1 h incorporation of [14C]leucine. We conclude that a significant portion of ferritin mRNA always associates with the ER-bound polyribosomes, and that inflammation and iron differentially alter the polysomal distribution of ferritin mRNA, suggesting that two different kinds of mRNA may be involved.     

Iron overload,measured as serum ferritin,increases brain damage induced by focal ischemia and early reperfusion

High levels of iron, measured as serum ferritin, are associated to a worse outcome after stroke. However, it is not known whether ischemic damage might increase ferritin levels as an acute phase protein or whether iron overload affects stroke outcome. The objectives are to study the effect of stroke on serum ferritin and the contribution of iron overload to ischemic damage.     

Mucosal iron binding proteins and the inhibition of iron absorption by endotoxin

The uptake of iron from a tied off jejunal segment into the body after the injection of a 59Fe labeled test dose was decreased after the administration of endotoxin by about 80% in both normal and iron deficient animals.--In the iron deficient group the distribution of 59Fe in the cytosol fraction of jejunal mucosa between transferrin and ferritin was determined chromatographically; the amount of 59Fe in the ferritin fraction increased remarkably after the endotoxin treatment and the ratio of both was changed in favor of ferritin.--It is hypothesized that the association of the diversion of iron to the mucosal ferritin with the decrease of the transport of iron into the blood caused by endotoxin might be the consequence of abnormal oxidations in the mucosa measured by others in liver tissue.     

Long-term zinc and iron supplementation in children of short stature: effect of growth and on trace element content in tissues.

We evaluated the effect of one year of supplementation with iron plus zinc (12 mg/day of Fe+++ and 12.5 mg/day of Zn++), zinc alone (12.5 mg/day of Zn++) and placebo on growth and on the iron, zinc, copper and selenium tissue contents in 30 well-selected children of short stature (16 M and 14 F; 4-11 years old). Before and after supplementation, we measured the concentrations of iron, transferrin, ferritin, zinc and copper in serum, of zinc in erythrocytes and leukocytes, and of zinc, copper and selenium in hair, as well as glutathione peroxidase activity in erythrocytes. Before supplementation, ferritin and serum, erythrocyte and hair zinc contents were significantly lower than in age-matched controls, while the other measured indices were in the normal range. Iron plus zinc supplementation caused an improvement in growth rate in all subjects, i.e., the median Z-score increased from -2.22 +/- 0.45 to -0.64 +/- 0.55; (p < 0.01). In the zinc-supplemented group, only the subjects whose ferritin levels were higher than 20 ng/L before supplementation showed a similar improvement of growth rate. Iron plus zinc supplementation could be a reasonable treatment in short, prepubertal children affected by marginal zinc and iron deficiency.     

Iron overload,measured as serum ferritin,increases brain damage induced by focal ischemia and early reperfusion

High levels of iron, measured as serum ferritin, are associated to a worse outcome after stroke. However, it is not known whether ischemic damage might increase ferritin levels as an acute phase protein or whether iron overload affects stroke outcome. The objectives are to study the effect of stroke on serum ferritin and the contribution of iron overload to ischemic damage.Swiss mice were fed with a standard diet or with a diet supplemented with 2.5% carbonyl iron to produce iron overload. Mice were submitted to permanent (by ligature and by in situ thromboembolic models) or transient focal ischemia (by ligature for 1 or 3 h).Treatment with iron diet produced an increase in the basal levels of ferritin in all the groups. However, serum ferritin did not change after ischemia. Animals submitted to permanent ischemia had the same infarct volume in the groups studied. However, in mice submitted to transient ischemia followed by early (1 h) but not late reperfusion (3 h), iron overload increased ischemic damage and haemorrhagic transformation.Iron worsens ischemic damage induced by transient ischemia and early reperfusion. In addition, ferritin is a good indicator of body iron levels but not an acute phase protein after ischemia.     

Enzyme‐linked immunosorbent assay to quantitate serum ferritin in the northern fur seal (Callorhinus ursinus)

Serum ferritin concentration correlates with tissue iron stores in humans, horses, calves, dogs, cats, and pigs. Serum ferritin is considered the best serum analyte to predict total body iron stores in these species, and is more reliable than serum iron or total iron‐binding capacity, both of which may be affected by disorders unrelated to iron adequacy or excess (including hypoproteinemia, chronic infection, hemolytic anemia, hypothyroidism, renal disease, and drug administration). Iron overload has been documented to result in hemochromatosis in captive northern fur seals (Callorhinus ursinus); therefore, we developed an enzyme‐linked immunosorbent assay (ELISA) to measure serum ferritin in this species. The assay uses two murine anti‐canine ferritin monoclonal antibodies in a sandwich arrangement that was originally used in an ELISA to measure serum ferritin in dogs. Ferritin isolated from fur seal liver was used as a standard. Ferritin standards were linear from 0 to 50 ng/ml. Recovery of purified ferritin from fur seal serum varied from 89% to 99%. The within‐assay variability was 6%, and the assay‐to‐assay variability for two different samples was 10% and 16%. Zoo Biol 23:79‐84, 2004.© 2004 Wiley‐Liss, Inc.     

The effect of the flavonol rutin on serum and liver iron content in a genetic mouse model of iron overload

The flavonol rutin has been shown to possess antioxidant and iron chelating properties in vitro and in vivo. These dual properties are beneficial as therapeutic options to reduce iron accumulation and the generation of reactive oxygen species (ROS) resultant from excess free iron. The effect of rutin on iron metabolism has been limited to studies performed in wildtype mice either injected or fed high-iron diets. The effect of rutin on iron overload caused by genetic dysregulation of iron homoeostasis has not yet been investigated. In the present study we examined the effect of rutin treatment on tissue iron loading in a genetic mouse model of iron overload, which mirrors the iron loading associated with Type 3 hereditary haemochromatosis patients who have a defect in Transferrin Receptor 2 (TFR2). Male TFR2 knockout (KO) mice were administered rutin via oral gavage for 21 continuous days. Following treatment, iron levels in serum, liver, duodenum and spleen were assessed. In addition, hepatic ferritin protein levels were determined by Western blotting, and expression of iron homoeostasis genes by quantitative real-time PCR. Rutin treatment resulted in a significant reduction in hepatic ferritin protein expression and serum transferrin saturation. In addition, trends towards decreased iron levels in the liver and serum, and increased serum unsaturated iron binding capacity were observed. This is the first study to explore the utility of rutin as a potential iron chelator and therapeutic in an animal model of genetic iron overload.     

Synthesis of ferritin by neuroblastoma

Ferritin is an iron-containing protein which is a normal component of serum. The levels of ferritin are increased in the sera of some children with neuroblastoma, and this increase appears to be a potent indicator of prognosis. To determine whether synthesis of ferritin by the tumor cells contributes to these increased serum levels, we examined incorporation of radiolabeled leucine by CHP 126, a neuroblastoma derived cell line, into ferritin. Using sequential immunoprecipitation and gel electrophoresis of sonicates from cells maintained in medium containing iron in amounts standard for tissue culture, incorporation of label into ferritin was 0.04% of that into total protein synthesized over the same time period. Addition of up to 40 micrograms of iron as ferric ammonium citrate increased ferritin synthesis to a maximum of 0.16% without altering synthesis of total protein. The pattern of iron-induced enhancement in the neuroblastoma cells was similar to that which was seen using Chang liver cells, a cell line well known to be capable of ferritin synthesis. These results confirm that neuroblastoma cells can synthesize ferritin and that synthesis is regulated by exogenous iron.     

Tissue Iron Distribution Assessed by MRI in Patients with Iron Loading Anemias

Bone marrow, spleen, liver and kidney proton transverse relaxation rates (R2), together with cardiac R2* from patients with sickle cell disease (SCD), paroxysmal nocturnal hemoglobinuria (PNH) and non-transfusion dependent thalassemia (NTDT) have been compared with a control group. Increased liver and bone marrow R2 values for the three groups of patients in comparison with the controls have been found. SCD and PNH patients also present an increased spleen R2 in comparison with the controls. The simultaneous measurement of R2 values for several tissue types by magnetic resonance imaging (MRI) has allowed the identification of iron distribution patterns in diseases associated with iron imbalance. Preferential liver iron loading is found in the highly transfused SCD patients, while the low transfused ones present a preferential iron loading of the spleen. Similar to the highly transfused SCD group, PNH patients preferentially accumulate iron in the liver. A reduced spleen iron accumulation in comparison with the liver and bone marrow loading has been found in NTDT patients, presumably related to the differential increased intestinal iron absorption. The correlation between serum ferritin and tissue R2 is moderate to good for the liver, spleen and bone marrow in SCD and PNH patients. However, serum ferritin does not correlate with NTDT liver R2, spleen R2 or heart R2*. As opposed to serum ferritin measurements, tissue R2 values are a more direct measurement of each tissue’s iron loading. This kind of determination will allow a better understanding of the different patterns of tissue iron biodistribution in diseases predisposed to tissue iron accumulation.     

The Effect of Iron Treatment on Adhesion Molecules in Patients with Iron Deficiency Anemia

The present study was aimed to determine the effect of iron supplementation on levels of soluble intercellular adhesion molecule-1 (sICAM-1) and soluble vascular cell adhesion molecule-1 (sVCAM-1) in patients with iron deficiency anemia (IDA). In this study, 26 female patients diagnosed with iron deficiency were treated approximately 3 months of oral iron supplementation (99 ± 10 days; ferrous glycine sulfate; 100 mg/day of elemental iron). Levels of sICAM-1 and sVCAM-1 were assessed prior to treatment and after approximately 3 months of treatment and compared with 26 healthy female subjects. A significant increase in sVCAM levels was found in the patients with iron deficiency at the end of the treatment relative to pretreatment levels compared to controls, whereas no significant differences were determined in sICAM levels. In the posttreatment period, no significant change was observed in sICAM levels compared to the pretreatment levels, whereas sVCAM levels decreased. However, after the treatment period, the sVCAM, hemoglobin, mean corpuscular volume (MCV), and serum ferritin levels did not return to the normal range compared to the controls. Pretreatment sVCAM-1 levels were inversely correlated with levels of hemoglobin, hemotocrit, MCV, serum iron, and ferritin. After treatment, the sVCAM-1 levels were negatively correlated with ferritin levels. Levels of sVCAM were significantly higher in patients with IDA than controls. After the treatment period, the sVCAM levels were not completely normalized in patients with IDA compared to controls, regardless of the presence of inadequate levels of hemoglobin, MCV, and serum ferritin. Thus, iron supplementation not only ameliorates anemia, but may also reduce the inflammation markers in cases with IDA.     

Iron overload syndromes

Iron overload is relatively common and is now detected more frequently because of inclusion of serum iron measurement in automated clinical chemistry panels. Secondary hemosiderosis and hemochromatosis result from increased iron absorption associated with increased erythropoiesis compensating for hemolysis, increased dietary iron, inappropriate prolonged oral iron therapy or chronic multiple transfusions. Primary hemochromatosis is a genetic metabolic disorder associated with the HLA locus on chromosome 6 resulting in increased iron absorption, though erythropoiesis and dietary iron are normal, and abnormal diversion of iron from reticuloendothelial (RE) to parenchymal cells. A genetic increase of intracellular iron carrier is a proposed basic mechanism. Only in the cirrhotic stage of primary hemochromatosis do RE iron and serum ferritin increase. Since both serum iron and serum ferritin may remain normal in the precirrhotic stage and may be falsely positive in the absence of iron overload, direct measurement of body iron stores is often useful. Measurement of tissue iron in liver biopsy specimens is widely used. However, quantitation of total mobilizable body iron by measurement of a 6-hour urine collection after intravenous injection of 59Fe-DTPA is noninvasive, sensitive, relatively accurate, and together with other laboratory and clinical data provides a practical means of establishing the correct diagnosis and therapy early enough to minimize organ damage.     

Iron reduction by deferoxamine leads to amelioration of adiposity via the regulation of oxidative stress and inflammation in obese and type 2 diabetes KKAy mice

Iron is an essential trace metal for most organisms. However, excess iron causes oxidative stress through production of highly toxic hydroxyl radicals via the Fenton/Haber-Weiss reaction. Iron storage in the body is reported to be associated with fat accumulation and type 2 diabetes mellitus. We investigated the role of iron in adiposity by using KKAy mice and obese and diabetic model mice. Eight-week-old KKAy mice were divided into two groups and treated with deferoxamine (DFO), an iron chelator agent, or a vehicle for 2 wk. DFO treatment diminished fat iron concentration and serum ferritin levels in KKAy mice. Fat weight and adipocyte size were reduced significantly in DFO-treated mice compared with vehicle-treated mice. Macrophage infiltration into fat was also decreased in DFO-treated mice compared with vehicle-treated mice. Superoxide production and NADPH oxidase activity in fat, as well as urinary 8-hydroxy-2'-deoxyguanosine excretion, were decreased in KKAy mice after DFO treatment while p22(phox) expression in adipose tissue was diminished in such mice. Ferritin expression in the fat of DFO-treated KKAy mice was decreased. In addition, F4/80-positive cells also presented through both p22(phox) and ferritin expression. The mRNA expression levels of inflammatory cytokines were also reduced in fat tissue of DFO-treated mice. These findings suggest that reduction of iron levels ameliorates adipocyte hypertrophy via suppression of oxidative stress, inflammatory cytokines, and macrophage infiltration, thereby breaking a vicious cycle in obesity.