Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Iron Overload”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 595 records · Page 33Linked to original sources
PubMed1982

Sideroblastic anaemia with iron overload presenting as an arthropathy.

We report on 2 patients with sideroblastic anaemia an secondary iron overload whose presenting symptom was an arthropathy of small an large joints. One patient had marked spinal symptoms which were severe enough to suggest ankylosing spondylitis, and the pattern of arthritis in the other resembled seronegative rheumatoid arthritis. We believe these to be the first cases described of an arthropathy associated with iron overload secondary to sideroblastic anaemia.

Adult↗
PubMedDate not supplied

Transferrin receptor-2 (TFR2) mutation Y250X in Alabama Caucasian and African American subjects with and without primary iron overload.

Most cases of hemochromatosis are associated with mutations of the HFE gene on Ch6p. In southern Italy and central Alabama, the percentages of patients with hemochromatosis who have "atypical" HFE genotypes (defined as lack of C282Y homozygosity, C282Y/H63D compound heterozygosity, or H63D homozygosity) are relatively great. A mutation of the transferrin receptor-2 gene (TFR2; exon 6, nt 750 C --> G, replaces TAC with stop signal TAG; Y250X) on Ch7q22 was recently identified in two Sicilian families with HFE mutation-negative hemochromatosis. We wanted to estimate the frequency of this mutation in persons from central Alabama. We evaluated Caucasian hemochromatosis probands with atypical HFE genotypes and African Americans with primary iron overload. We also studied control Caucasians, including persons of southern Italian/Sicilian heritage, and control African Americans. Analysis of genomic DNA was performed using a PCR-sequence-specific priming assay and positive control specimens from Sicilian hemochromatosis subjects heterozygous and homozygous for Y250X. Among Alabama subjects, this allele was not detected in 113 Caucasians, including 21 hemochromatosis probands with atypical HFE genotypes and 92 normal control subjects (including 27 of southern Italian/Sicilian descent). In African Americans, Y250X was not detected in 20 index cases with primary iron overload or in 274 unrelated control subjects. We conclude that Y250X is uncommon in Caucasians with hemochromatosis associated with atypical HFE genotypes, in African Americans with primary iron overload, and in the general Caucasian and African American population subgroups in central Alabama.

Alabama↗
PubMed1990

Biological and ultrastructural aspects of iron overload: an overview.

The morphologic aspects of iron overload have been studied in human subjects, mammals, and birds with spontaneous overload, in a variety of experimental animals, and also in cell cultures. Reviewed here are the contributions of electron microscopy to the understanding of the iron-loading process, as reported during the last 12 years. The electron-density of ferrihydrite cores located within the protein shell of the ferritin molecule enabled its identification within either cytosol or lysosomes (siderosomes) of iron-exposed cells. The process of (holo)ferritin assembly, its transfer into siderosomes, and its degradation to hemosiderin can be followed in various cells. Siderosomes display cell-line-specific ultrastructural features, and different cell types show varying iron-segregating capacity. The study of experimental animals and cultured cells show that an iron-rich milieu may be damaging, probably through iron-catalyzed lipid peroxidation. Recent ultrastructural studies stress the value of describing initial alterations as opposed to the irrelevant end-stage findings. Further efforts should be directed toward elucidating the origin of iron in neonatal hemochromatosis, the role of iron in infection and neoplasia, and the nature and role of brain iron.

Absorption↗
PubMed1975

Serum ferritin in patients with iron overload and with acute and chronic liver diseases.

An immunoradiometric assay was used to determine serum ferritin in patients with iron overload disorders and in patients with liver disease. In patients with iron overload, serum ferritin was closely correlated in an exponential manner with quantitative measurements of storage iron; however, a different relationship applied when storage iron levels were within normal range, suggesting that circulating ferritin is in equilibrium with two functionally distinct tissue ferritin pools. High ferritin levels were common in patients both with acute and chronic liver disease, normal values being virtually confined to women and to subjects with a history of recent hemorrhage. In liver disease generally, serum ferritin varied both with the serum transaminase level and with liver iron concentration, but correlated well with neither factor separately. There was no correlation with the serum iron or total iron-binding capacity. An extremely close correlation was found between serum ferritin and an empirical index derived from the product of the serum transaminase times liver iron concentration, implying that the circulating level depended on both the degree of hepatocellular injury and liver iron store. There was a close linear correlation between the serum ferritin-transaminase ratio and liver iron concentration in all disorders studied, and this index may prove to be the most useful value for diagnostic purposes.

Acetaminophen↗
PubMed1986

Dietary iron overload persists in rural sub-Saharan Africa.

In a survey of 505 rural Zimbabweans, iron overload was found almost exclusively among men who consumed traditional beer brewed in steel drums. Among drinkers aged over 45 years, 23 of 111 men (21%) had high serum ferritin and a transferrin saturation of over 70%, a combination that indicates a risk of liver disease and other pathological effects from excess body iron. Iron overload, which is reported to be decreasing among urban Africans, may remain a public health issue in rural areas where more than 80% of the people of sub-Saharan Africa live.

Adult↗
PubMed2004

Measurement of liver iron overload by magnetic induction using a planar gradiometer: preliminary human results.

The measurement of hepatic iron overload is of particular interest in cases of hereditary hemochromatosis or in patients subject to periodic blood transfusion. The measurement of plasma ferritin provides an indirect estimate but the usefulness of this method is limited by many common clinical conditions (inflammation, infection, etc). Liver biopsy provides the most quantitative direct measurement of iron content in the liver but the risk of the procedure limits its acceptability. This work studies the feasibility of a magnetic induction (MI) low-cost system to measure liver iron overload. The excitation magnetic field (B0, frequency: 28 kHz) was produced by a coil, the perturbation produced by the object (deltaB) was detected using a planar gradiometer. We measured ten patients and seven volunteers in supine and prone positions. Each subject was moved in a plane parallel to the gradiometer several times to estimate measurement repeatability. The real and imaginary parts of deltaB/B0 were measured. Plastic tanks filled with water, saline and ferric solutions were measured for calibration purposes. We used a finite element model to evaluate the experimental results. To estimate the iron content we used the ratio between the maximum values for real and imaginary parts of deltaB/B0 and the area formed by the Nyquist plot divided by the maximum imaginary part. Measurements in humans showed that the contribution of the permittivity is stronger than the contribution of the permeability produced by iron stores in the liver. Defined iron estimators show a limited correlation with expected iron content in patients (R < or = 0.56). A more precise control of geometry and position of the subjects and measurements at multiple frequencies would improve the method.

Computer Simulation↗
PubMed2002

Role of liver biopsy in the diagnosis of hepatic iron overload in the era of genetic testing.

We studied hepatic iron overload (HIOL) patterns in 32 patients who underwent liver biopsies and testing for HFE mutations (C282Y, H63D). Iron-stained biopsy specimens were examined for patterns of iron deposits: hereditary hemochromatosis (HH) pattern or non-HH pattern. Visual iron grade based on amount of cellular and lobular iron was evaluated. We found the HH pattern in 17 biopsy specimens (53%) and the non-HH pattern in 6 specimens (19%). HH with superimposed non-HH was noted in 9 cases (28%). In 25 patients with HFE mutations, HH alone and combined with non-HH patterns was noted in 22 specimens (88%). Visual iron grade correlated approximately with the hepatic iron index. Heavy HIOL was noted in C282Y homozygotes and 1 patient with cirrhosis without either HFE mutation. Mild steatohepatitis was found in 21 specimens (66%); it was associated with the non-HH pattern in 80% (12/15) and the HH pattern in 62% (16/26) of cases. Liver biopsy can identify pattern and grade of HIOL and associated pathology for diagnosis and management of patients with abnormal iron studies and elevated liver function test results. Genetic tests for HFE mutations and liver biopsies are complementary in the workup of these patients.

Adult↗
PubMed2006

The overlapping of local iron overload and HFE mutation in venous leg ulcer pathogenesis.

Chronic venous stasis determines red blood cell extravasation and either dermal hemosiderin deposits or iron-laden phagocytes. Several authors have suspected that iron could play a role in the pathogenesis of venous leg ulcers. They hypothesized that local iron overload could generate free radicals or activate a proteolytic hyperactivity on the part of metalloproteinases (MMPs) or else down-regulate tissue inhibitors of MMPs. However, they were unable to explain why iron deposits, visible in the legs of patients with chronic venous disease (CVD), cause lesions in only some individuals, whereas in others they do not. We hypothesized that such individual differences could be genetically determined and investigated the role of the C282Y and H63D mutations of the HFE gene. C282Y mutation significantly increases the risk of ulcer in primary CVD more than six times (OR = 6.69; 1.45-30.8; p = 0.01). Patients carrying the H63D variant have an earlier age of ulcer onset, by almost 10 years (p > 0.004). The increased risk of skin lesion and the early age of onset of the disease in HFE carriers confirm in a clinical setting that intracellular iron deposits of mutated macrophages have less stability than those of the wild type. We hypothesize that the physiologic iron protective mechanisms are affected by the HFE mutations and should be investigated in all diseases characterized by the combination of iron overload and inflammation.

Female↗
PubMed2006

Mixture models of serum iron measures in population screening for hemochromatosis and iron overload.

Homozygosity for the C282Y mutation of the hemochromatosis gene on chromosome 6p (HFE) is a common genetic trait that increases susceptibility to iron overload. The authors describe and apply methodology developed for the analysis of phenotypic and genotypic data from 46,136 non-Hispanic Caucasians, a subset of the multi-ethnic cohort enrolled in the Hemochromatosis and Iron Overload Screening (HEIRS) Study. For analysis of the distribution of transferrin saturation (TS), mixtures of normal distributions were considered and the expectation-maximization (EM) algorithm was applied for parameter estimation. Maximized log-likelihoods were compared, and significance was assessed by resampling. Sensitivity, specificity, and predictive values from the modeled subpopulations were compared with the actual observed genotypes for C282Y and H63D mutations in the HFE gene. A strong association between HFE genotype and TS subpopulations was found in these data collected from different geographic regions, confirming the external validity of the statistical approach when applied to population-based data. It was concluded that mixture modeling of phenotypic data may provide a clinical guide for screening with gender-specific thresholds to identify potential samples for genetic testing.

Adult↗
PubMed1996

Oxidative stress and antioxidant status in beta-thalassemia major: iron overload and depletion of lipid-soluble antioxidants.

Because of continuous blood transfusions, thalassemia patients are subjected to peroxidative tissue injury by the secondary iron overload. In accordance, analysis of serum from 42 beta-thalassemia patients, aged 4 to 40 years, showed that the mean concentrations of conjugated diene lipid hydroperoxides (CD), lipoperoxides evaluated as malondialdehyde/ thiobarbituric acid (MDA/TBA) adducts, and protein carbonyls increased about twofold with respect to control. Ferritin levels were positively correlated with the amount of MDA (r = .41; P = .007) and showed a positive trend with CD (r = .31; P = .07) and protein carbonyls (r = .35; P = .054), as further evidence of the deleterious effects of high tissue iron levels. Marked changes in the antioxidant pattern were also observed in all patients. Evidence is presented of a net drop in the concentration of ascorbate (-44%), vitamin E (-42%), vitamin A(-44%), beta-carotene (-29%), and lycopene (-67%). On the other hand, an increase of uric acid and bilirubin was observed, whereas serum albumin and glutathione were in the normal range in all patients. As a result, the total serum antioxidant potential, measured as trolox equivalent antioxidant capacity appeared significantly decreased by 14%. Serum levels of vitamin E were inversely correlated with ferritin (r = -.45; P = .003), suggesting a major consumption of this antioxidant under iron overload. Nontransferrin bound iron (NTBI) was in the range 4.5 to 54.8 micrograms/dL (mean, 21.8 +/- 13.9). Although NTBI had a positive trend with ferritin (r = .37, P = .03), no clear correlation was found with either MDA or vitamin E. A mild to severe hepatic damage, as assessed by serum transaminases, was shown in 24 of 42 patients. Serum levels of vitamin E (r = -.49, P = .015), vitamin A (r = -.48, P = .016) and lycopene (r = -.47, P = .020), were inversely correlated with the levels of transminases. On the other hand, lipid-soluble antioxidants in thalassemia patients were depleted to the same extent in hepatitis C virus (HCV)-infected (31 subjects) and in HCV-uninfected (10 subjects), while in the normal range in serum from 30 nonthalassemic patients with HCV-related chronic hepatitis. These results point out that the iron-induced liver damage in thalassemia may play a major role in the depletion of lipid-soluble antioxidants. The variations of the parameters evaluated in the present study were not correlated with the age of the patients. Our results suggest that the measurement of peroxidation products, matched with evaluation of antioxidants, may be a simple measure of iron toxicity in thalessemia, in addition to the conventional indices of iron status.

Adolescent↗
PubMed2003

Emerging understanding of the advantage of small molecules such as hydroxypyridinones in the treatment of iron overload.

Deferiprone, a hydroxypyridin-4-one, is effective at facilitating iron removal from iron overloaded patients, when administered orally. Some problems associated with deferiprone are discussed. Hydroxypyridinone analogues with improved distribution, metabolism and affinity for iron are described. In particular the "high pFe(3+)" hydroxypyridin-4-ones possess considerable clinical potential.

Animals↗
PubMed2007

Morbidity and mortality in chronically transfused subjects with thalassemia and sickle cell disease: A report from the multi-center study of iron overload.

A natural history study was conducted in 142 Thalassemic (Thal), 199 transfused Sickle Cell Disease (Tx-SCD, n = 199), and 64 non-Tx-SCD subjects to describe the frequency of iron-related morbidity and mortality. Subjects recruited from 31 centers in the US, Canada or the UK were similar with respect to age (overall: 25 +/- 11 years, mean +/- SD) and gender (52% female). We found that Tx-SCD subjects were hospitalized more frequently compared with Thal or non-Tx-SCD (P < 0.001). Among those hospitalized, Tx-SCD adult subjects were more likely to be unemployed compared with Thal (RR = 1.6, 95% CI 1.0-2.5) or non-Tx-SCD (RR = 3.1, 95% CI 1.3-7.3). There was a positive relationship between the severity of iron overload, assessed by serum ferritin, and the frequency of hospitalizations (r= 0.20; P = 0.009). Twenty-three deaths were reported (6 Thal, 17 Tx-SCD) in 23.5 +/- 10 months of follow-up. Within the Tx-SCD group, those who died began transfusion (25.3 vs. 12.4 years, P < 0.001) and chelation therapy later (26.8 vs. 14.2 years, P = 0.01) compared with those who survived. The unadjusted death rate in Thal was lower (2.2/100 person years) compared with that in Tx-SCD (7.0/100 person years; RR = 0.38: 95% CI 0.12-0.99). However, no difference was observed when age at death was considered. Despite improvements in therapy, death rate in this contemporary sample of transfused adult subjects with Thal or SCD is 3 times greater than the general US population. Long term follow-up of this unique cohort of subjects will be helpful in further defining the relationship of chronic, heavy iron overload to morbidity and mortality.

Adolescent↗
PubMed2002

Effects of iron overload and hepatitis C virus positivity in determining progression of liver fibrosis in thalassemia following bone marrow transplantation.

To identify the role of iron overload in the natural history of liver fibrosis, we reviewed serial hepatic biopsy specimens taken annually from patients cured of thalassemia major by bone marrow transplantation. The patients underwent transplantation between 1983 and 1989 and did not receive any chelation or antiviral therapy. Two hundred eleven patients (mean age, 8.7 +/- 4 years) were evaluated for a median follow-up of 64 months (interquartile range, 43-98 months) by a median number of 5 (interquartile range, 3-6) biopsy samples per patient. Hepatic iron concentration was stratified by tertiles (lower, 0.5-5.6 mg/g; medium, 5.7-12.7 mg/g; upper, 12.8-40.6 mg/g dry weight). Forty-six (22%) patients showed signs of liver fibrosis progression; the median time to progression was 51 months (interquartile range, 36-83 months). In a multivariate Cox proportional hazard model, the risk for fibrosis progression correlated to medium hepatic iron content (hazard rate, 1.9; 95% confidence interval [CI], 0.74-5.0), high hepatic iron content (hazard rate, 8.7; 95% CI, 3.6-21.0) and hepatitis C virus (HCV) infection (hazard rate, 3.1; 95% CI, 1.5-6.5). A striking increase in the risk for progression was found in the presence of both risk factors. None of the HCV-negative patients with hepatic iron content lower than 16 mg/g dry weight showed fibrosis progression, whereas all the HCV-positive patients with hepatic iron concentration greater than 22 mg/g dry weight had fibrosis progression in a minimum follow-up of 4 years. Thus, iron overload and HCV infection are independent risk factors for liver fibrosis progression, and their concomitant presence results in a striking increase in risk.

Adolescent↗
PubMed2005

Intron 2 [IVS2, T-C +4] HFE gene mutation associated with S65C causes alternative RNA splicing and is responsible for iron overload.

UNLABELLED: A patient with congenital liver fibrosis revealed a high transferrin saturation index and iron overload on liver biopsy. He did not carry the most frequent HFE mutations: C282Y or H63D. Heterozygosity was detected for S65C. Unknown HFE mutations were also sought using a combined denaturing high performance liquid chromatography (DHPLC)/direct sequence approach and another point mutation, a transition T-C (nt 4910), at the fourth base of the donor splice site of intron 2 [HFE, intervening sequence (IVS) 2, T-C +4] was found. Family screening revealed that a daughter carried both S65C and [IVS2, T-C +4]. CONCLUSION: : The existence in our proband of a partly-altered HFE protein in the region encoded by exon 2 might be responsible for the histologically-demonstrated iron overload.

Journal Article↗
PubMed1988

[Ferrokinetic studies with Fe-59 in idiopathic hemochromatosis and other forms of iron overload].

Conventional ferrokinetic studies were done in patients with idiopathic hemochromatosis, secondary siderosis of the liver and iron overload in consequence of sideroblastic or aplastic anaemia. By means of the isotope 59Fe we determined the clearance of radioiron from the plasma, the plasma iron turnover, the utilization of iron by the erythropoesis and the iron uptake by the liver. The later value showed a good correlation with the iron content of the liver determined by atomic absorption spectrometry as well in patients with hemochromatosis as in patients with secondary siderosis of the liver. The 59Fe uptake by the liver was normal in treated hemochromatosis. There was no correlation between the degree of the iron overload and the 59Fe uptake by the liver in patients with anaemia.

Anemia, Aplastic↗
PubMed2006

Two new human DMT1 gene mutations in a patient with microcytic anemia, low ferritinemia, and liver iron overload.

DMT1 mediates the pH-dependent uptake of Fe(2+) from the diet in duodenal enterocytes and in most other cells. It transfers iron from the endosomes to the cytosol following the uptake of the transferrin-transferrin receptor complex. DMT1 mutations are responsible for severe hypochromic microcytic anemia in rodents and in 2 human patients described recently. We report a compound heterozygote for 2 new DMT1 mutations, associated with microcytic anemia from birth and progressive liver iron overload. The first mutation is a GTG deletion in exon 5, leading to the V114 in-frame deletion in transmembrane domain 2, and the second is a G --> T substitution in exon 8 leading to the G212V replacement in transmembrane domain 5. Together with the 2 previously reported cases, this patient defines a new syndrome of congenital microcytic hypochromic anemia, poorly responsive to oral iron treatment, with liver iron overload associated paradoxically with normal to moderately elevated serum ferritin levels.

Amino Acid Sequence↗
PubMed2000

Anthracycline cardiotoxicity in a black rhinoceros (Diceros bicornis): evidence for impaired antioxidant capacity compounded by iron overload.

Two weeks before dying of congestive heart failure, a juvenile black rhinoceros (Diceros bicornis minor) received a single low dose of doxorubicin as part of combination chemotherapy for acute lymphoblastic leukemia. Diffuse hemosiderosis was present at necropsy in a pattern indicative of dietary iron overload, but unique iron-positive degenerative lesions were found in isolated myocardiocytes. Serum analyses revealed hyperferremia, 87% transferrin saturation, and 5- to 10-fold elevations in ferritin concentration, reflecting markedly increased tissue iron stores. Since both toxic and therapeutic effects of anthracyclines are mediated by formation of reactive free radicals via iron-catalyzed reactions, these observations suggest that iron overload may have enhanced myocardial susceptibility to cardiotoxic effects of doxorubicin. Impairments in other myocardial antioxidant defenses, such as deficiencies in catalase and glutathione S-transferase that are known to exist in rhinoceros erythrocytes, may have been underlying factors contributing to an inherent sensitivity of rhinoceros tissues to oxidant-induced injury.

Animals↗
PubMed2004

Low dose-ethanol modulates toxic effect of iron-overloading in the liver.

UNLABELLED: The oxidant properties of iron-overload and simultaneous ethanol consumption have received much interest, due to evidence reporting from hereditary hemochromatosis (HC). The full form of this disease is often associated with chronic alcoholism. An additive effect of toxicity of iron and ethanol was assumed. In this study, we examined nutritively iron-loaded Wistar rats (n = 59) (TMH-Ferrocene) additionally fed with ethanol up to 8% in drinking water for 36 wk. METHODS: By reverse-phase HPLC we measured the concentration of ascorbic acid, tocopherole and retinol in serum and liver homogenates as well as transaminases in the serum. Lipid peroxidation was assessed utilizing the ethane-exhalation method. Iron concentration in the liver was measured with the Bathophenanthrolin-method. Liver histology was performed to investigate the iron deposits and the organ damage (H.E., Azan and Berlin-blue-stainings). RESULTS: 1. Vitamin C: A linear decrease of the concentration of vitamin C in serum and liver was found independent of alcohol and iron uptake. 2. Vitamin E: Animals fed iron and alcohol showed elevated vitamin E concentrations in the serum but not in the liver. 3. Vitamin A: Elevated levels in serum but strongly decreasing levels in liver could be measured. 4. HISTOLOGY: All iron-fed animals showed massive deposits of iron in the liver. Iron diet caused liver cirrhosis, while an additional administration of ethanol could prevent this. 5. Lipid peroxidation increased in animals fed ethanol and iron, but was significantly lower in animals only receiving an iron diet. CONCLUSION: Evidence indicates that the additional exposition to ethanol in iron-loaded animals could modulate the organ damage and oxidative stress. The biochemical findings are positively correlated to the histology.

Alanine Transaminase↗