β-thalassemia is a type of inherited hemolytic anemia caused by decreased globin production due to defect of the HBB gene. The pathogenesis of the disease is imbalance of α/β globin chains. The excess of α-globin chains will form hemichromes which can damage red blood cell membranes and lead to hemolysis, ineffective erythropoiesis, and secondary iron overload. Iron overload in turn can cause complications such as growth retardation, liver cirrhosis, cardiac insufficiency, and aggravate the disease phenotype. In recent decades, genes participating in iron metabolism have been discovered, and the mechanism of iron metabolism in the development of thalassemia has gradually been elucidated. Subsequently, by manipulating the expression of key genes in iron metabolism such as hepcidin and transferrin receptor, researchers have revealed that iron restriction can improve ineffective hematopoiesis and iron overload, which may provide a potential approach for the treatment of thalassemia. This article reviews the progress of research on iron metabolism-related genes and related pathways in β-thalassemia.
Humans ; Iron/metabolism* ; Iron Overload/genetics* ; Phenotype ; Research/trends* ; beta-Thalassemia/physiopathology*

Haemochromatosis is characterised by elevated transferrin saturation (TSAT) and progressive iron loading that mainly affects the liver. Early diagnosis and treatment by phlebotomy can prevent cirrhosis, hepatocellular carcinoma, diabetes, arthropathy and other complications. In patients homozygous for p.Cys282Tyr in HFE, provisional iron overload based on serum iron parameters (TSAT >45% and ferritin >200 μg/L in females and TSAT >50% and ferritin >300 μg/L in males and postmenopausal women) is sufficient to diagnose haemochromatosis. In patients with high TSAT and elevated ferritin but other HFE genotypes, diagnosis requires the presence of hepatic iron overload on MRI or liver biopsy. The stage of liver fibrosis and other end-organ damage should be carefully assessed at diagnosis because they determine disease management. Patients with advanced fibrosis should be included in a screening programme for hepatocellular carcinoma. Treatment targets for phlebotomy are ferritin <50 μg/L during the induction phase and <100 μg/L during the maintenance phase.
Male ; Humans ; Female ; Hemochromatosis/therapy* ; Hemochromatosis Protein/genetics* ; Carcinoma, Hepatocellular/complications* ; Iron Overload/genetics* ; Ferritins ; Liver Cirrhosis/complications* ; Iron ; Fibrosis ; Liver Neoplasms/complications* ; Transferrins

OBJECTIVETo investigate the expression of divalent metal transporter 1 (DMT1) mRNA in male Sprague-Dawley rat heart of different ages and the expression of DMT1 regulated by dietary iron.

METHODSReverse transcriptase (RT)-PCR and Western blot were used in this study.

RESULTS(1)Two isoforms of DMT1 mRNA [with and without iron-responsive element (IRE)] were both detected in rat heart, which were correlated with heart iron content. During development, both of two isoforms of DMT1 mRNA expression were the lowest at the age of PND 7, and increased at PND 21, 63 to 196. (2) After fed with a high iron diet or low iron diet for 6 weeks, the rats developed iron overload or iron deficiency respectively. No significant differences in DMT1 mRNA expression were detected among iron overload, iron deficiency and control rats. By using Western blot analysis, a 21% and 40% reduction in DMT1 protein non IRE form and IRE form respectively were found in iron overload rat (P<0.01, compared with control). Increases (26% approximate, equals 28%) in the levels of two isoforms of DMT1 protein were also observed in iron deficient rat (P<0.01, compared with control).

CONCLUSIONThe level of DMT1 mRNA expression in heart is age dependent;the two isoforms of DMT1 protein may be both regulated by iron on the posttranscriptional mechanism.

Age Factors ; Animals ; Cation Transport Proteins ; genetics ; Gene Expression Regulation, Developmental ; Iron ; deficiency ; Iron Overload ; metabolism ; Iron-Binding Proteins ; genetics ; Male ; Myocardium ; metabolism ; RNA, Messenger ; analysis ; Rats ; Rats, Sprague-Dawley ; Response Elements

OBJECTIVE: To explore the effect of chronic iron overload on the lesion of atherosclerosis (AS) in apolipoprotein (apo) E knockout mice. METHODS: Twenty-four ApoE knockout mice were randomly divided into ApoE knockout group (0.1 mL saline for 4 weeks) and iron overload group (10 mg iron dextran for 4 weeks). The levels of serum iron (SI), total iron binding capacity, contents of malondialdehyde (MDA), and activity of superoxide dismutase (SOD) in the liver were measured. Iron deposition in the liver and heart was determined, and atherosclerotic plaque areas of the sinus aortae were analyzed. RESULTS: In the iron overload group, the levels of SI increased by 377.86%, the saturation of transferrin increased by 121.98% and the levels of iron in the liver increased by 2,548.15% (P<0.01). The contents of MDA in the liver increased by 32.51% (P<0.01), and the activity of SOD in the liver decreased by 17.2% in the ApoE knockout group (P<0.05). The level of MDA in the liver increased by 411.15%, and the activity of SOD in the liver decreased by 46.84% in the iron overload group (P<0.01). There was a significant deposition of iron in the liver and heart of mice, and the areas of atherosclerotic plaque of sinus aortae increased markedly in the iron overload group. CONCLUSION Chronic iron overload may promote the development of AS lesion in the ApoE knockout mice, in which the increased oxidative stress and lipid oxidation may involve.
Animals ; Apolipoproteins E ; genetics ; metabolism ; Atherosclerosis ; etiology ; metabolism ; pathology ; Iron ; blood ; Iron Overload ; complications ; Male ; Mice ; Mice, Inbred C57BL ; Mice, Knockout ; metabolism ; Oxidative Stress ; Random Allocation ; Superoxide Dismutase ; metabolism ; Transferrin ; metabolism

BACKGROUNDS/AIMS: There are controversies on the role of iron overload in the mechanism of liver injury in nonalcoholic fatty liver disease (NAFLD). The aim of this study was to evaluate the prevalence of peripheral iron overload, and to study the presence of HFE mutations (C282Y, H63D, S65C) in a cohort of Korean NAFLD patients. METHODS: 255 patients with NAFLD were included. The patients had been diagnosed as having NAFLD by the criteria of elevated aminotransferase levels, compatible ultrasonographic findings and exclusion of other etiologies. Blood samples were tested for chemistry, iron profile, and mutational analysis for HFE gene (C282Y, H63D, S65C). RESULTS: Of the 255 NAFLD patients, the prevalence of peripheral iron overload was 19.2% according to the cutoff level of transferrin saturation (TS) > 45%, and 3.9% of NAFLD patients were having hyperferritinemia over 400 ng/mL. Hyperferritinemia was significantly associated with elevated serum levels of fasting glucose, AST and TS. We found the presence of H63D mutation, either heterozygote or homozygote, among the NAFLD patients with peripheral iron overload. CONCLUSIONS: The prevalence of peripheral iron overload in the Korean NAFLD patients was not rare, and the presence of H63D mutation among NALFD patients was identified. Further studies on the significance of iron overload or HFE mutation in the pathogenesis of NAFLD are needed.
Adult ; Cohort Studies ; Fatty Liver/*etiology/genetics ; Female ; Heterozygote ; Histocompatibility Antigens Class I/*genetics ; Homozygote ; Humans ; Iron Overload/complications/*epidemiology ; Korea ; Male ; Membrane Proteins/*genetics ; Middle Aged ; Point Mutation ; Prevalence ; Transferrin/metabolism

OBJECTIVETo detect the incidence of the HFE gene C282Y and H63D mutations in patients with myelodysplastic syndromes (MDS) and aplastic anemia (AA), and analyze the relationship of these mutations with iron metabolism, and organs impairment from iron overload.

METHODSThe incidence of the C282Y and H63D mutations in 271 MDS, 402 AA patients and 1615 normal subjects was measured by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) combining with DNA sequencing. Iron metabolism parameters and iron overload indices were retrospectively compared between HFE gene mutation and unmutation groups in MDS and AA patients with no transfusion history.

RESULTSNo C282Y and C282Y/H63D compound mutation was detected in all the three groups. The incidence of H63D heterozygous and homozygous genotype did not significantly differ between AA cases and controls (9.7% vs 10.2%, 0.25% vs 0.24% respectively, both P > 0.05). The frequency of H63D heterozygous genotype in MDS patients was significantly lower than that in controls (4.1% vs 10.2%, P = 0.002). H63D homozygous was not found in MDS patients. In both MDS and AA patients with no RBC transfusion history, serum ferritin (SF), transferrin saturation value (TS), serum iron concentration (SI) were close to or higher than normal; and unsaturated iron-binding capacity (UIBC) value was significantly lower. There was no significant difference in SF, SI, TS values between HFE-mutation and -unmutation MDS patients. For AA patients, only the level of SI was significantly higher in HFE-mutant group than in -unmutation group [42.6 (24.6-60.4) micromol/L vs 32.0 (8.4-63.3) micromol/L, P = 0.011]. There was no significant difference in the values of liver enzyme, fasting blood sugar (FBS), abnormal electrocardiogram (ECG), peripheral blood indices between HFE-mutation and -unmutation MDS and AA groups (all P > 0.05).

CONCLUSIONThe distribution of C282Y and H63D mutations has ethnic and genetic disparity, the frequency in Chinese population is lower than that in Caucasian. It seems that MDS and AA patients are susceptible to iron overload, in the diseases itself and the mutations of HFE gene are not the major factor for iron overload in the patients.

Adolescent ; Adult ; Aged ; Aged, 80 and over ; Anemia, Aplastic ; complications ; genetics ; Case-Control Studies ; Child ; Child, Preschool ; China ; Female ; Genotype ; Hemochromatosis Protein ; Histocompatibility Antigens Class I ; genetics ; Humans ; Iron ; blood ; Iron Overload ; etiology ; genetics ; Male ; Membrane Proteins ; genetics ; Middle Aged ; Mutation ; Myelodysplastic Syndromes ; complications ; genetics ; Young Adult