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Query: UMLS:C0240066 (iron deficiency)
 7,156 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Iron is an element which is essential to life but also potentially toxic. Therefore, clever mechanisms exist in the human body for uptake, transport and storage of iron. Hepcidin, which seems to be the master protein for regulation of intestinal iron absorption, is known for a short time. The expression of hepcidin is not only influenced by iron levels but also by mediators of inflammation and growth factors of erythropoiesis. Hence hepcidin plays also a crucial role in the development of anemia of chronic disease and iron overload due to ineffective erythropoiesis. Serum ferritin is a reliable parameter to estimate the storage iron. It is an acute phase protein which is elevated during infections and inflammations, though. In these situations, measurement of soluble transferrin receptors is a useful tool to differentiate between iron deficiency and anemia of chronic disease. Newer parameters as erythrocyte zink protoporphyrin or percentage of hypochromic erythrocytes (%HYPO) are suited to detect a functional iron deficiency. Early diagnosis of iron overload is essential to prevent organ damage. Serum ferritin and transferrin are useful parameters to screen for iron overload. If no clear reason for a secondary iron overload can be found, the search for a hereditary haemochromatosis is recommended. Most of these hereditary haemochromatoses are a result of mutations in the HFE gene (homozygous state for Cys282Tyr or compound heterozygosity for Cys282Tyr/ His63Asp) which can be detected by PCR technique. Liver biopsy is still the gold standard for quantification of storage iron. However, a method of increasing importance for quantification of iron overload is magnetic resonance imaging with new approaches as for example T2*.
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PMID:[Old and new iron parameters in iron metabolism and diagnostics]. 1879 66

Chronic venous disease (CVD), mainly due to venous reflux or, sometimes, to venous outflow obstruction, produces a microcirculatory overload leading to the impairment of venous drainage. Venous drainage depends primarily on a major hemodynamic parameter called trans-mural pressure (TMP). TMP is increased in patients affected by CVD, leading to impaired tissue drainage, and, consequently, facilitating the beginning of the inflammatory cascade. Increased TMP determines red blood cell extravasation and either dermal hemosiderin deposits or iron laden-phagocytes. Iron deposits are readily visible in the legs of all patients affected by severe CVD. Local iron overload could generate free radicals or activate a proteolytic hyperactivity of metalloproteinases (MMPs) and/or downregulate tissue inhibitors of MMPs. These negative effects are particularly evident in carriers of the common HFE gene's mutations C282Y and H63D, because intracellular iron deposits of mutated macrophages have less stability than those of the wild type, inducing a significant oxidative stress. It has been demonstrated that such genetic variants increase the risk of ulcers and advance the age of ulcer onset, respectively. The iron-dependent vision of inflammation in CVD paves the way to new therapeutic strategies including the deliberate induction of iron deficiency as a treatment modality for non-healing and/or recurrent venous leg ulcers. The inflammatory cascade in CVD shares several aspects with that activated in the course of multiple sclerosis, an inflammatory and neurodegenerative disease of unknown origin in which the impairment of cerebral venous outflow mechanisms has been recently demonstrated.
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PMID:Inflammation in venous disease. 1897 97

Iron metabolism has been implicated in carcinogenesis and several studies assessed the potential role of genetic variants of proteins involved in iron metabolism (HFE C282Y, TFR S142G) in different malignancies. Few reports addressed this issue with relation to chronic myeloproliferative disorders (CMPD). The aims of our study were (a) to examine the potential associations of CMPD development with genetic modifiers of iron metabolism in a large cohort of CMPD patients; (b) to examine associations of genetic variants of proteins involved in iron metabolism; and acquired JAK2 V617F mutation with clinical characteristics of CMPD. HFE C282Y was genotyped in 328 CMPD patients and 996 blood donors as controls, HFE H63D, and TFR S142G were tested in CMPD patients and 171 first time blood donors. JAK2 V617F mutation was tested in CMPD patients and in 122 repeated blood donors. Decreased C282Y allele frequency (allele frequency+/-95% confidence interval) was found in the CMPD group (1.8%+/-1.0%) compared with controls (3.4%+/-0.8%; P=0.048). TFR S142G allele frequency was reduced among V617F-negative CMPD patients (34.8%+/-7.6%) compared with controls (47.8%+/-5.4%; P=0.02). The frequency of JAK2 V617F was 75.9% (249 of 328) in the CMPD group. At presentation, elevated hemoglobin levels were found in V617F-positive patients compared with V617F-negative counterparts (P<0.000). Vascular complications (26.6% versus 15.2%; P=0.039) as well as female gender (57.4% versus 41.8%; P=0.019) were more common in V617F-positive patients. We found that HFE C282Y might be associated with a protective role against CMPD. Because chronic iron deficiency or latent anemia may trigger disease susceptibility for CMPD, HFE C282Y positivity may be a genetic factor influencing this effect.
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PMID:HFE C282Y mutation as a genetic modifier influencing disease susceptibility for chronic myeloproliferative disease. 1925 83

Hereditary hemochromatosis is an iron overload disorder that can lead to the impairment of multiple organs and is caused by mutations in one or more different genes. Type 1 hemochromatosis is the most common form of the disease and results from mutations in the HFE gene. Juvenile hemochromatosis (JH) is the most severe form, usually caused by mutations in hemojuvelin (HJV) or hepcidin (HAMP). The autosomal dominant form of the disease, type 4, is due to mutations in the SLC40A1 gene, which encodes for ferroportin (FPN). Hereditary hemochromatosis is commonly found in populations of European origin. By contrast, hemochromatosis in Asia is rare and less well understood and can be masked by the presence of iron deficiency and secondary iron overload from thalassemia. Here, we provide a comprehensive report of hemochromatosis in a group of patients of Asian origin. We have identified novel mutations in HJV, HAMP, and SLC40A1 in countries not normally associated with hereditary hemochromatosis (Pakistan, Bangladesh, Sri Lanka, and Thailand). Our family studies show a high degree of consanguinity, highlighting the increased risk of iron overload in many countries of the developing world and in countries in which there are large immigrant populations from these regions.
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PMID:Iron overload in the Asian community. 1957 77

The hepatic peptide hormone hepcidin plays a central role in body iron metabolism. Despite its promise as a biomarker, the availability of high-sensitive hepcidin assays is still limited. We developed and validated a RadioImmunoAssay (RIA) to measure hepcidin quantitatively in human serum. This assay exhibited a very low detection limit (0.02 microg/l), low imprecision (coefficient of variation-range 4.4-6.2%) and good linearity and recovery (range: 81-105%). Hepcidin levels of samples of controls and patients with iron deficiency and inflammation showed an excellent correlation with our previously described quantitative time-of-flight mass spectrometry assay (range 2.5-266.8 microg/l, r = 0.92, P < 0.0001). The RIA detected: (i) differences in mean hepcidin levels between men (n = 29) and women (n = 35), (ii) differences between individuals of different HFE-genotypes (n = 60) and (iii) daily increases in hepcidin levels (n = 64). The assay (i) is easy to perform and many samples can be processed within one assay-run, (ii) shows accurate, reproducible and high-sensitive measurements and (iii) is anticipated to be particularly useful to study the effects of pathological and physiological stimuli on hepcidin levels in the lower range.
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PMID:High-sensitive radioimmunoassay for human serum hepcidin. 1950 86

Hemoglobin (Hb) levels and mean corpuscular volume (MCV) are abnormal in some persons with hemochromatosis or thyroid disorders. We sought to determine whether serum free thyroxine (T4) affects erythrocyte measures in euthyroid adults with or without C282Y homozygosity. We evaluated 488 white HFE C282Y homozygotes and controls (no HFE C282Y or H63D; normal serum iron measures) identified in screening; we excluded those with thyroid disorders, anemia, erythrocytosis, or serum ferritin (SF) <34 pmol/l. In the remaining 141 C282Y homozygotes and 243 controls, we evaluated correlations of log(10) free T4 with Hb, RBC, MCV, and red blood cell distribution width (RDW). C282Y homozygotes had lower mean age, higher mean Hb, MCV, and log(10) SF, and lower mean RBC and RDW than controls; mean log(10) free T4 did not differ significantly. In HFE C282Y homozygotes, there was no significant correlation of log(10) T4 with erythrocyte measures. In controls, there was a positive correlation of log(10) T4 with Hb (P = 0.0096) and a negative correlation with RDW (P = 0.0286). Among euthyroid white adults without iron deficiency, there are significant correlations of log(10) free T4 with Hb and RDW in controls, but not in HFE C282Y homozygotes.
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PMID:Relationships of serum free thyroxine and erythrocyte measures in euthyroid HFE C282Y homozygotes and control subjects: the HEIRS study. 1970 67

Limited data are available about iron deficiency (ID) in Brazilian blood donors. This study evaluated the frequencies of ID and iron-deficiency anaemia (IDA) separately and according to frequency of blood donations. The protective effect of the heterozygous genotype for HFE C282Y mutation against ID and IDA in female blood donors was also determined. Five hundred and eight blood donors were recruited at the Blood Bank of Santa Casa in Sao Paulo, Brazil. Haemoglobin and serum ferritin concentrations were measured. The genotype for HFE C282Y mutation was determined by polymerase chain reaction followed by restriction fragment length polymorphism analysis. The ID was found in 21.1% of the women and 2.6% of the men whereas the IDA was found in 6.8 and 0.3%, respectively. The ID was found in 11.9% of the women in group 1 (first-time blood donors) and the frequency increased to 38.9% in women of the group 3 (blood donors donating once or more times in the last 12 months). No ID was found in men from group 1; however the ID frequency increased to 0.9% in group 2 (who had donated blood before but not in the last 12 months) and 5.0% in group 3. In summary, the heterozygous genotype was not associated with reduction of ID or IDA frequencies in both genders, but in male blood donors it was associated with a trend to elevated ferritin levels (P = 0.060). ID is most frequent in Brazilian women but was also found in men of group 3.
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PMID:Iron deficiency and frequency of HFE C282Y gene mutation in Brazilian blood donors. 1974 87

Iron overload is a risk factor for hepatocarcinoma, but the pathways involved are poorly characterized. Gene expression analysis in immortalized mouse hepatocytes exposed to iron or the iron chelator deferoxamine revealed that iron downregulated, whereas deferoxamine upregulated, mRNA levels of mouse double minute gene 2 (MDM2), the ubiquitin ligase involved in the degradation of the oncosuppressor p53. Regulation of MDM2 by iron status was observed at protein levels in mouse hepatocytes and rat liver, and was associated with specular changes in p53 expression. Iron dependent regulation of MDM2/p53 was confirmed ex-vivo in human monocytes, by manipulation of iron pool and in a genetic model of iron deficiency, leading to modulation of p53 target genes involved in the antioxidant response and apoptosis. Iron status influenced p53 ubiquitination and degradation rate, and the MDM2 inhibitor nutlin increased p53 levels in iron-depleted cells. Furthermore, nutlin enhanced the antiproliferative activity of deferoxamine in HepG2 hepatoblastoma cells. The MDM2 -309T > G promoter polymorphism, determining increased MDM2 and lower p53 activity, was associated with higher risk of hepatocarcinoma in cirrhotic patients with hemochromatosis, and with HFE mutations in patients with hepatocarcinoma without hemochromatosis, suggesting an interaction between MDM2 and iron in the pathogenesis of hepatocarcinoma. In conclusion, iron status influences p53 activity and antioxidant response by modulating MDM2 expression. MDM2 inhibitors may enhance the antiproliferative activity of iron chelators.
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PMID:Iron-dependent regulation of MDM2 influences p53 activity and hepatic carcinogenesis. 2001 89

Iron is essential in the brain, yet too much iron can be toxic. Tight regulation of iron in the brain may involve intrinsic mechanisms that control internal homeostasis independent of systemic iron status. Iron abnormalities occur in various neurological disorders, usually with symptoms or neuropathology associated with movement impairment or behavioral disturbances rather than cognitive impairment or dementia. Consistent with this, polymorphisms in the HFE gene, associated with the iron overload disorder hemochromatosis, show stronger associations with the movement disorder amyotrophic lateral sclerosis (motor neuron disease) than with cognitive impairment. Such associations may arise because certain brain regions involved in movement or executive control are particularly iron-rich, notably the basal ganglia, and may be highly reliant on iron. Various mechanisms, including iron redistribution causing functional iron deficiency, lysosomal and mitochondrial abnormalities or oxidative damage, could underlie iron-related neuropathogenesis. Clarifying how iron contributes causatively to neurodegeneration may improve treatment options in a range of neurodegenerative disorders. This review considers how modern molecular genetic approaches can be applied to resolve the complex molecular systems and pathways by which brain iron homeostasis is regulated and the molecular changes that occur with iron dyshomeostasis and neuropathogenesis.
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PMID:Molecular genetic approaches to understanding the roles and regulation of iron in brain health and disease. 2034 52

Iron is an essential trace element in mammalian metabolism. Body iron stores require a tight regulation to avoid detrimental effects due to iron excess or to iron deficiency. Iron losses being not adaptable, iron balance is controlled only through intestinal iron absorption which is regulated by the hepatic peptide hepcidin. Hepcidin synthesis is controlled by several genes including the HFE, hemojuvelin and transferrin receptor 2 genes. Mutations in these genes lead to a phenotype of hemochromatosis. Recently, the bone morphogenetic protein 6 was shown to be the key endogenous ligand involved in the cascade regulating hepcidin synthesis.
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PMID:The iron driven pathway of hepcidin synthesis. 2053 80


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