Iron Deficiency and Overload

HFE gene mutations in patients with primary iron overload: is there a significant improvement in molecular diagnosis yield with HFE sequencing?

Rare HFE variants have been shown to be associated with hereditary hemochromatosis (HH), an iron overload disease. The low frequency of the HFE p.C282Y mutation in HH-affected Brazilian patients may suggest that other HFE-related mutations may also be implicated in the pathogenesis of HH in this population. The main aim was to screen for new HFE mutations in Brazilian individuals with primary iron overload and to investigate their relationship with HH. Fifty Brazilian patients with primary iron overload (transferrin saturation>50% in females and 60% in males) were selected. Subsequent bidirectional sequencing for each HFE exon was performed. The effect of HFE mutations on protein structure were analyzed by molecular dynamics simulation and free binding energy calculations. p.C282Y in homozygosis or in heterozygosis with p.H63D were the most frequent genotypic combinations associated with HH in our sample population (present in 17 individuals, 34%). Thirty-six (72.0%) out of the 50 individuals presented at least one HFE mutation. The most frequent genotype associated with HH was the homozygous p.C282Y mutation (n=11, 22.0%). One novel mutation (p.V256I) was indentified in heterozygosis with the p.H63D mutation. In silico modeling analysis of protein behavior indicated that the p.V256I mutation does not reduce the binding affinity between HFE and β2-microglobulin (β2M) in the same way the p.C282Y mutation does compared with the native HFE protein. In conclusion, screening of HFE through direct sequencing, as compared to p.C282Y/p.H63D genotyping, was not able to increase the molecular diagnosis yield of HH. The novel p.V256I mutation could not be implicated in the molecular basis of the HH phenotype, although its role cannot be completely excluded in HH-phenotype development. Our molecular modeling analysis can help in the analysis of novel, previously undescribed, HFE mutations.

Hereditary hemochromatosis: a literature review and case report

PURPOSE

To improve understanding in the physical therapy (PT) community of hereditary hemochromatosis (HH), a common but little-known iron overload disorder, symptoms of which may mimic other orthopaedic conditions. Medical management typically involves phlebotomy to remove excess iron; however, there is little specific information in the literature on PT management of patients with HH after trauma.

CASE DESCRIPTION

The patient was a 65-year-old woman with multiple fall-related traumas, including right wrist, thumb, and patellar fractures and left thigh muscle strain with significant ecchymosis and effusion. Medical history included HH. Iron-related lab values had been analyzed 9 days prior to the fall and had demonstrated a steady increase over the previous 4 months since her last phlebotomy.

OUTCOMES

As the level of exercise and activity increased during the course of PT treatment, the patient developed shortness of breath and increased fatigue. The exercise level in therapy was reduced to accommodate the change in the patient's response. Blood values analyzed 7 weeks after the fall demonstrated a drop in haemoglobin and hematocrit values, while serum ferritin levels had risen.

IMPLICATIONS

Understanding early symptoms and management of a patient with manifestations of HH will better enable physical therapists to consider this disorder as a differential diagnosis or co-morbidity that affects treatment considerations.

Quantitative susceptibility map reconstruction from MR phase data using bayesian regularization: validation and application to brain imaging

The diagnosis of many neurologic diseases benefits from the ability to quantitatively assess iron in the brain. Paramagnetic iron modifies the magnetic susceptibility causing magnetic field inhomogeneity in MRI. The local field can be mapped using the MR signal phase, which is discarded in a typical image reconstruction. The calculation of the susceptibility from the measured magnetic field is an ill-posed inverse problem. In this work, a bayesian regularization approach that adds spatial priors from the MR magnitude image is formulated for susceptibility imaging. Priors include background regions of known zero susceptibility and edge information from the magnitude image. Simulation and phantom validation experiments demonstrated accurate susceptibility maps free of artifacts. The ability to characterize iron content in brain hemorrhage was demonstrated on patients with cavernous hemangioma. Additionally, multiple structures within the brain can be clearly visualized and characterized. The technique introduces a new quantitative contrast in MRI that is directly linked to iron in the brain.

A novel negative Fe-deficiency-responsive element and a TGGCA-type-like FeRE control the expression of FTR1 in Chlamydomonas reinhardtii

We have reported three Fe-deficiency-responsive elements (FEREs), FOX1, ATX1, and FEA1, all of which are positive regulatory elements in response to iron deficiency in Chlamydomonas reinhardtii. Here we describe FTR1, another iron regulated gene and mutational analysis of its promoter. Our results reveal that the FeREs of FTR1 distinguish itself from other iron response elements by containing both negative and positive regulatory regions. In FTR1, the −291/−236 region from the transcriptional start site is necessary and sufficient for Fe-deficiency-inducible expression. This region contains two positive FeREs with a TGGCA-like core sequence: the FtrFeRE1 (ATGCAGGCT) at −287/−279 and the FtrFeRE2 (AAGCGATTGCCAGAGCGC) at −253/−236. Furthermore, we identified a novel FERE, FtrFeRE3 (AGTAACTGTTAAGCC) localized at −319/−292, which negatively influences the expression of FTR1.

Erythropoiesis-stimulating agents in anemia: use and misuse

Erythropoiesis-stimulating agents (ESAs) have been in use for 2 decades. After the initial introduction for their use in anemia of end-stage renal disease, indications for the use of ESAs have widened to anemia of predialysis chronic kidney disease, cancer chemotherapy, HIV disease and orthopedic surgery. Along with the considerable benefits associated with the use of ESAs, adverse events have become apparent, in large part from overcorrection of the anemia. Data from recent studies have prompted several FDA warnings imposing the health provider to follow stringent criteria for the use of ESAs; these include close follow-up of patients, along with use of specific laboratory tests and criteria for dosing. Although adverse effects may partly relate to misuse, when appropriately administered, ESAs are useful agents in the medication armamentarium in the treatment of certain forms of anemia, with potential to improve outcomes and quality of life in some anemic individuals.

Baseline iron indices as predictors of hemoglobin improvement in anemic Vietnamese women receiving weekly iron-folic acid supplementation and deworming

Iron deficiency anemia is highly prevalent among women living in rural Vietnam. However, the utility and cut-offs of indices for diagnosing iron deficiency anemia in the public health context is ill defined. We assessed the ability of iron indices to predict the hemoglobin response (HBR) to weekly iron-folic acid supplementation (WIFS) in anemic rural Vietnamese women. We compared hemoglobin, serum ferritin, and soluble transferrin receptor in a cohort of 221 non-pregnant women of reproductive age before and after 3 months of WIFS and deworming. At baseline, anemia (Hb < 120 g/L) was present in 81/221 (36.7%) of subjects. After 3 months, anemia prevalence fell to 58/221 (26.2%), and the mean hemoglobin change was +3.5 g/L (95% confidence interval, 0.9, 6.6). A hemoglobin response was observed in 50/75 (66.6%) of anemic women. A ferritin cut-off < 30 ng/mL was a more sensitive predictor of response than ferritin < 15 ng/mL.

SRC-mediated phosphorylation of dynamin and cortactin regulates the "constitutive" endocytosis of transferrin

The mechanisms by which epithelial cells regulate clathrin-mediated endocytosis (CME) of transferrin are poorly defined and generally viewed as a constitutive process that occurs continuously without regulatory constraints. In this study, we demonstrate for the first time that endocytosis of the transferrin receptor is a regulated process that requires activated Src kinase and, subsequently, phosphorylation of two important components of the endocytic machinery, namely, the large GTPase dynamin 2 (Dyn2) and its associated actin-binding protein, cortactin (Cort). To our knowledge these findings are among the first to implicate an Src-mediated endocytic cascade in what was previously presumed to be a nonregulated internalization process.

A guide to diagnosis of iron deficiency and iron deficiency anemia in digestive diseases

Iron deficiency (ID), with or without anemia, is often caused by digestive diseases and should always be investigated, except in very specific situations, as its causes could be serious diseases, such as cancer. Diagnosis of ID is not always easy. Low serum levels of ferritin or transferrin saturation, imply a situation of absolute or functional ID. It is sometimes difficult to differentiate ID anemia from anemia of chronic diseases, which can coexist. In this case, other parameters, such as soluble transferrin receptor activity can be very useful. After an initial evaluation by clinical history, urine analysis, and serological tests for celiac disease, gastroscopy and colonoscopy are the key diagnostic tools for investigating the origin of ID, and will detect the most important and prevalent diseases. If both tests are normal and anemia is not severe, treatment with oral iron can be indicated, along with stopping any treatment with non-steroidal anti-inflammatory drugs. In the absence of response to oral iron, or if the anemia is severe or clinical suspicion of important disease persists, we must insist on diagnostic evaluation. Repeat endoscopic studies should be considered in many cases and if both still show normal results, investigating the small bowel must be considered. The main techniques in this case are capsule endoscopy, followed by enteroscopy.

Iron overload, hematopoietic cell transplantation, and graft-versus-host disease

Many patients who undergo hematopoietic cell transplantation (HCT) present with anemia and have received red blood cell transfusions before HCT. As a result, iron overload is frequent and appears to be particularly prominent in patients with myelodysplastic syndromes. There is evidence that peritransplant events contribute to further iron accumulation, although the mechanism that disrupts normal iron homeostasis remains to be determined. Recent studies suggest that iron overload, as determined by ferritin levels, a surrogate marker for iron, is a risk factor for increased non-relapse mortality after HCT. Iron overload is associated with an increased rate of infections, in particular with fungal organisms. Furthermore anecdotal data suggest that increased hepatic iron may mimic the clinical picture of (chronic) graft-versus-host-disease (GVHD). Whether excess iron contributes to GVHD and whether iron depletion, be it by phlebotomy or chelation, reduces the post-transplantation complication rate and improves transplant outcome is yet to be determined.

Iron overload in survivors of childhood leukemia after allogeneic hematopoietic stem cell transplantation

Iron overload has not been studied extensively and prospectively in pediatric survivors of allogeneic hematopoietic stem cell transplantation (HSCT); therefore, we conducted a prospective long-term study of 133 survivors of childhood leukemia to assess the incidence of and risk factors for iron overload and to investigate its association with organ dysfunction. One yr after HSCT, the mean serum ferritin level was 1158 ng/mL (range, 22-3264 ng/mL), with 124 patients (93.2%) having a serum ferritin level that exceeded the upper limit of the normal range (110 ng/mL). Thereafter, the serum ferritin level declined over time. There was a positive correlation between the level of serum ferritin and that of total bilirubin (r = 0.21, p < 0.001) and glutamate pyruvate transaminase (r = 0.17, p < 0.001). A high concentration of serum ferritin was associated with low cardiac fractional shortening (r = -0.15, p = 0.047). In addition, patients with hypothyroidism and GH deficiency had a higher level of serum ferritin than those without (p < 0.02). We conclude that iron overload is common after HSCT and is associated with hepatic, cardiac, and endocrine dysfunction.

Altered iron metabolism in children with human immunodeficiency virus disease

BACKGROUND

Despite the high prevalence of altered iron metabolism in children with human immunodeficiency virus (HIV) disease, these alterations have not been well studied.

PROCEDURES

Twenty-six children with HIV disease underwent laboratory evaluation to determine the presence of anemia, and to classify the anemia as iron-deficiency anemia or anemia of chronic disease.

RESULTS

Half of the children had an alteration in iron metabolism: 6 were iron deficient, 4 had hyperferritinemia, and 3 demonstrated hyperferritinemia with iron deficiency.

CONCLUSIONS

These data indicate that alterations in iron metabolism are common even in the HAART era and warrant further study to identify individuals at risk for these alterations.

Hemochromatosis gene status as a risk factor for Barrett's esophagus

Conditions causing high iron levels, such as hemochromatosis, are proposed risk factors for esophageal adenocarcinoma. Although this hypothesis is supported by animal models, no human data currently exist. We conducted a case-control study of persons with a new Barrett's esophagus diagnosis (cases), persons with gastroesophageal reflux disease (GERD) (without Barrett's esophagus), and population controls. Subjects completed detailed examinations and assays for hemochromatosis mutations and serum iron stores. We evaluated 317 cases, 306 GERD patients, and 308 population controls. There was no significant association between Barrett's esophagus and any hemochromatosis gene defect (odds ratio [OR] = 1.32, 95% confidence interval [CI]: 0.95-1.84), a moderate or severe mutation (OR = 1.54, 95% CI: 0.94-2.52), or a severe mutation (C282Y homozygote or C282Y/H63D heterozygote; OR = 0.77, 95% CI: 0.24-2.48) compared with the population controls. As expected, gene defects were associated with increased iron stores. We can conclude from our findings that Barrett's esophagus was not associated with hemochromatosis gene defects, although we cannot exclude small effects.

Iron intake and body iron stores as risk factors for Barrett's esophagus: a community-based study

OBJECTIVE

High iron stores are a proposed modifiable risk factor for esophageal adenocarcinoma, but minimal human data exist. We evaluated whether iron intake and iron stores were associated with Barrett's esophagus, a metaplastic change that is a strong risk factor for esophageal adenocarcinoma.

METHODS

We conducted a case-control study within the Kaiser Permanente Northern California population. We identified all persons with a new diagnosis of Barrett's esophagus (cases); they were matched to persons with GERD (without Barrett's esophagus) and to population controls. Subjects completed examinations, dietary questionnaires, and testing for serum iron stores (ferritin and transferrin saturation). Analyses used unconditional logistic regression.

RESULTS

We evaluated 319 cases, 312 GERD patients, and 313 population controls. Compared with population controls, Barrett's esophagus patients had lower dietary iron intakes (4th vs 1st quartiles, odds ratio [OR]= 0.37, 95% confidence interval [CI] 0.17-0.80), similar total iron intakes (including supplement use), and lower iron stores (4th vs 1st quartiles, ferritin OR = 0.24, 95% CI 0.14-0.40;% transferrin saturation OR = 0.66, 95% CI 0.41-1.04; P value trend <0.01 and 0.03, respectively). Similar associations were observed in comparisons with GERD controls and among subjects without clear sources of blood loss on endoscopy.

CONCLUSIONS

Patients with Barrett's esophagus had lower dietary iron intakes and lower serum iron stores than controls in our population. These findings do not provide support for the current hypothesis that high iron stores or a high iron intake are risk factors for Barrett's esophagus, a potential early event in the carcinogenic sequence for esophageal adenocarcinoma.

Individualized treatment for iron-deficiency anemia in adults

Iron deficiency is one of the most common disorders affecting humans, and iron-deficiency anemia continues to represent a major public health problem worldwide. It is especially common among women of childbearing age because of pregnancy and menstrual blood loss. Additional patient groups include those with other sources of blood loss, malnutrition, or gut malabsorption. Iron-deficiency anemia remains prevalent despite the widespread ability to diagnose the disease and availability of medicinal iron preparations. Therefore, new approaches are needed to effectively manage these patient populations. In this review, the diagnosis and treatment of iron-deficiency anemia are discussed with emphasis placed on consideration of patient-specific features. It is proposed that all patients participate in their own care by helping their physician to identify a tolerable daily iron dose, formulation, and schedule. Dosing cycles are recommended for iron replacement based on the tolerated daily dose and the total iron deficit. Each cycle consists of 5000 mg of oral elemental iron ingested over at least 1 month with appropriate follow-up. This approach should assist physicians and their patients with the implementation of individualized treatment strategies for patients with iron-deficiency anemia.

Anemia associated with impaired erythropoietin secretion after allogeneic stem cell transplantation: incidence, risk factors, and response to treatment

After allogeneic stem cell transplantation (allo-SCT) some patients develop persistent anemia in association with an inadequate erythropoietin (Epo) secretion. We determined the frequency and risk factors for this complication and the response to treatment with erythropoiesis stimulating proteins (ESP). Of 83 evaluable allo-SCT patients, 63 (76%) developed persistent anemia at a median of 34 (range: 30-244) days after allo-SCT. Forty-one (49%) patients had anemia considered as primary, and in all of them inadequate serum Epo levels (median 43.3, range: 2.5-134, mU/mL) were found. A high creatinine level during the first month after allo-SCT was associated with primary anemia (relative risk [RR] 2.5, P = .01). Of the 41 patients, 35 received ESP. Transfusion independence and an Hb level higher than 10 g/dL was achieved in 29 of 30 (97%) evaluable patients. Median ferritin levels at the beginning and at the end of the ESP treatment was 1628 (range: 168-5208) and 805 (range: 14-7443) ng/mL, respectively (P = .04). In conclusion, anemia associated with impaired Epo secretion after allo-SCT is more frequent than usually recognized and it is associated to early postransplantation renal damage. This complication easily reverts with ESP, which seems to contribute to reduce iron overload.

Iron deficiency anemia

The most severe consequence of iron depletion is iron deficiency anemia (IDA), and it is still considered the most common nutrition deficiency worldwide. Although the etiology of IDA is multifaceted, it generally results when the iron demands by the body are not met by iron absorption, regardless of the reason. Individuals with IDA have inadequate intake, impaired absorption or transport, physiologic losses associated with chronological or reproductive age, or chronic blood loss secondary to disease. In adults, IDA can result in a wide variety of adverse outcomes including diminished work or exercise capacity, impaired thermoregulation, immune dysfunction, GI disturbances, and neurocognitive impairment. In addition, IDA concomitant with chronic kidney disease or congestive heart failure can worsen the outcome of both conditions. In this review, the prevalence of IDA related to confounding medical conditions will be described along with its diverse etiologies. Distinguishing IDA from anemia of chronic disease using hematologic measures is reviewed as well. In addition, current diagnostic strategies that are inclusive of clinical presentation, biochemical tests, and differential diagnosis will be outlined, followed by a discussion of treatment modalities and future research recommendations.

An iron responsive element-like stem-loop regulates alpha-hemoglobin-stabilizing protein mRNA

Hemoglobin production during erythropoiesis is mechanistically coupled to the acquisition and metabolism of iron. We discovered that iron regulates the expression of alpha-hemoglobin-stabilizing protein (AHSP), a molecular chaperone that binds and stabilizes free alpha-globin during hemoglobin synthesis. In primates, the 3'-untranslated region (UTR) of AHSP mRNA contains a nucleotide sequence resembling iron responsive elements (IREs), stem-loop structures that regulate gene expression post-transcriptionally by binding iron regulatory proteins (IRPs). The AHSP IRE-like stem-loop deviates from classical consensus sequences and binds IRPs poorly in electrophoretic mobility shift assays. However, in cytoplasmic extracts, AHSP mRNA co-immunoprecipitates with IRPs in a fashion that is dependent on the stem-loop structure and inhibited by iron. Moreover, this interaction enhances AHSP mRNA stability in erythroid and heterologous cells. Our findings demonstrate that IRPs can regulate mRNA expression through non-canonical IREs and extend the repertoire of known iron-regulated genes. In addition, we illustrate a new mechanism through which hemoglobin may be modulated according to iron status.

The role of zinc, copper and iron in the pathogenesis of diabetes and diabetic complications: therapeutic effects by chelators

Zinc (Zn), copper (Cu) and iron (Fe) are essential minerals that are required for a variety of biomolecules to maintain the normal structure, function, and proliferation of cells. These metals can be toxic in excessive amounts, especially in certain genetic disorders. The homeostasis of these trace elements results from a tightly coordinated regulation by different proteins involved in their uptake, excretion and intracellular storage/trafficking. Through the Fenton reaction, Cu and Fe under a non protein-binding condition, can generate various reactive oxygen species, damaging tissues or cells. Abnormal metabolism of Zn, Cu and Fe can lead to several chronic pathogenesis, such as diabetes or diabetic complications. These pathogenic conditions appear to be prevalent in Zn and Cu deficiency, as well as Cu and Fe overload. In the Fe and Cu overloading conditions, Fe and Cu chelating drugs could be used to control diabetes and diabetic complications. The essentiality, toxicity and roles of these metals in the pathogenesis of diabetes and diabetic complications are discussed.

Attenuation of acute and chronic liver injury in rats by iron-deficient diet

Oxidative stress due to iron deposition in hepatocytes or Kupffer cells contributes to the initiation and perpetuation of liver injury. The aim of this study was to clarify the association between dietary iron and liver injuries in rats. Liver injury was initiated by the administration of thioacetamide or ligation of the common bile duct in rats fed a control diet (CD) or iron-deficient diet (ID). In the acute liver injury model induced by thioacetamide, serum levels of aspartate aminotransferase and alanine aminotransferase, as well as hepatic levels of lipid peroxide and 4-hydroxynonenal, were significantly decreased in the ID group. The expression of 8-hydroxydeoxyguanosine and terminal deoxynucleotidyl transferase biotin-dUTP nick-end labeling positivity showed a similar tendency. The expression of interleukin-1beta and monocyte chemotactic protein-1 mRNA was suppressed in the ID group. In liver fibrosis induced by an 8-wk thioacetamide administration, ID suppressed collagen deposition and smooth muscle alpha-actin expression. The expressions of collagen 1A2, transforming growth factor beta, and platelet-derived growth factor receptor beta mRNA were all significantly decreased in the ID group. Liver fibrosis was additionally suppressed in the bile-duct ligation model by ID. In culture experiments, deferoxamine attenuated the activation process of rat hepatic stellate cells, a dominant producer of collagen in the liver. In conclusion, reduced dietary iron is considered to be beneficial in improving acute and chronic liver injuries by reducing oxidative stress. The results obtained in this study support the clinical usefulness of an iron-reduced diet for the improvement of liver disorders induced by chronic hepatitis C and alcoholic/nonalcoholic steatohepatitis.

A genome-wide linkage scan for iron phenotype quantitative trait loci: the HEIRS Family Study

Iron overload phenotypes in persons with and without hemochromatosis are variable. To investigate this further, probands with hemochromatosis or evidence of elevated iron stores and their family members were recruited for a genome-wide linkage scan to identify potential quantitative trait loci (QTL) that contribute to variation in transferrin saturation (TS), unsaturated iron-binding capacity (UIBC), and serum ferritin (SF). Genotyping utilized 402 microsatellite markers with average spacing of 9 cM. A total of 943 individuals, 64% Caucasian, were evaluated from 174 families. After adjusting for age, gender, and race/ethnicity, there was evidence for linkage of UIBC to chromosome 4q logarithm of the odds (LOD) = 2.08, p = 0.001) and of UIBC (LOD = 9.52), TS (LOD = 4.78), and SF (LOD = 2.75) to the chromosome 6p region containing HFE (each p < 0.0001). After adjustments for HFE genotype and other covariates, there was evidence of linkage of SF to chromosome 16p (LOD = 2.63, p = 0.0007) and of UIBC to chromosome 5q (LOD = 2.12, p = 0.002) and to chromosome 17q (LOD = 2.19, p = 0.002). We conclude that these regions should be considered for fine mapping studies to identify QTL that contribute to variation in SF and UIBC.

Optimal management strategies for chronic iron overload

Iron overload is characterised by excessive iron deposition and consequent injury and dysfunction of target organs, especially the heart, liver, anterior pituitary, pancreas and joints. Iron overload disorders are common worldwide and occur in most major race/ethnicity groups. Physiological mechanisms to excrete iron are very limited. Thus, all patients with iron overload need safe and effective treatment that is compatible with their co-existing medical conditions. Treatments for iron overload include phlebotomy and erythrocytapheresis that remove iron predominantly as haemoglobin, and chelation therapy with drugs that bind excess iron selectively and increase its excretion. The most important potential benefits of therapy are preventing deaths due to cardiac siderosis and hepatic cirrhosis. Preventing iron-related injury to endocrine organs is critical in children. Successful treatment or prevention of iron overload increases quality of life and survival in many patients. This article characterises the major categories of iron overload disorders, tabulates methods to evaluate and treat iron overload, and describes treatment options for iron overload disorders. Research needed to advance knowledge about treatment of iron overload is proposed.

Chelation therapy for iron overload

Iron overload is characterized by excessive iron deposition and consequent injury and dysfunction of the heart, liver, anterior pituitary, pancreas, and joints. Because physiologic mechanisms to excrete iron are very limited, patients with iron overload and its complications need safe, effective therapy that is compatible with their coexisting medical conditions. The availability of three licensed iron chelation drugs (one parenteral, two oral) and the development and clinical investigation of other oral chelators represent new opportunities to prevent or manage iron overload in patients with heritable types of severe anemia, such as beta-thalassemia major and sickle cell disease, and for the formulation of alternatives to phlebotomy therapy for patients with iron overload associated with the HFE gene and other adult age-of-onset types of hemochromatosis, African iron overload, and African-American iron overload.

Iron nutrition in the UK: getting the balance right

Fe homeostasis is considered in the context of the UK diet, using information on Fe intake and status from the National Diet and Nutrition Surveys. The importance of assessing Fe availability rather than total Fe intake is discussed. Dietary and host-related factors that determine Fe bioavailability (Fe utilised for Hb production) are reviewed using information from single-meal studies. When adaptive responses are taken into consideration, foods associated with higher Fe status include meat (haem-Fe and the ‘meat factor’) and fruits and fruit juice (vitamin C). Foods that may have a negative impact include dairy products (Ca), high-fibre foods (phytate) and tea and coffee (polyphenols), but the effects are more apparent in groups with marginal Fe deficiency, such as women of childbearing age. Analysis of dietary intake data on a meal-by-meal basis is needed to predict the influence of changing dietary patterns on Fe nutrition in the UK. Current information suggests that in the UK Fe deficiency is a greater problem than Fe overload.

Four-year evaluation of myocardial and liver iron assessed prospectively with serial MRI scans in young patients with ?-thalassaemia major: comparison between different chelation regimens

This study was conducted in order to assess myocardial and liver iron concentrations (LICs) using serial magnetic resonance imaging (MRI) scans in patients with beta-thalassaemia major, over a 4-yr period, and consequently to compare the effectiveness of different chelation regimens. Fifty children and young adults with beta-thalassaemia major (27 boys and 23 girls) were recruited (mean age: 14.74 +/- 3.67 yr). All patients underwent detailed clinical examination, electrocardiography, echocardiography, myocardial and liver MRI at the beginning of the study, 2 and 4 yr after. Additionally, serum ferritin levels were regularly measured and data regarding LICs assessed by percutaneous liver biopsy were available in 26 patients. Both myocardial and liver MRI values showed a moderate inverse correlation with age (r = -0.379, P < 0.001 and r = -0.376, P < 0.001, respectively). Liver MRI was better correlated with serum ferritin concentrations (r = -0.342, P < 0.001) than myocardial MRI (r = -0.186, P = 0.011). Liver MRI values were highly correlated with LICs derived from percutaneous liver biopsy (r = -0.863, P < 0.001), whereas myocardial MRI values did not correlate at all with measurements derived from echocardiography. Regarding iron chelation treatment, patients receiving combined therapy with deferiprone and deferoxamine (DFO) significantly reduced myocardial iron overload during the 4-yr study period, whilst patients in monotherapy with DFO showed a significant increase in LIC.

Molecular and clinical aspects of iron homeostasis: From anemia to hemochromatosis

The discovery in recent years of a plethora of new genes whose products are implicated in iron homeostasis has led to rapid expansion of our knowledge in the field of iron metabolism and its underlying complex regulation in both health and disease. Abnormalities of iron metabolism are among the most common disorders encountered in practical medicine and may have significant negative impact on physical condition and life expectancy. Basic insights into the principles of iron homeostasis and the pathophysiological and clinical consequences of iron overload, iron deficiency and misdistribution are thus of crucial importance in modern medicine. This review summarizes our current understanding of human iron metabolism and focuses on the clinically relevant features of hereditary and secondary hemochromatosis, iron deficiency anemia, anemia of chronic disease and anemia of critical illness. The interconnections between iron metabolism and immunity are also addressed, in as much as they may affect the risk and course of infections and malignancies.

Biochemistry, physiology, and complications of blood doping: facts and speculation

Competition is a natural part of human nature. Techniques and substances employed to enhance athletic performance and to achieve unfair success in sport have a long history, and there has been little knowledge or acceptance of potential harmful effects. Among doping practices, blood doping has become an integral part of endurance sport disciplines over the past decade. The definition of blood doping includes methods or substances administered for non-medical reasons to healthy athletes for improving aerobic performance. It includes all means aimed at producing an increased or more efficient mechanism of oxygen transport and delivery to peripheral tissues and muscles. The aim of this review is to discuss the biochemistry, physiology, and complications of blood doping and to provide an update on current antidoping policies.

Perioperative intravenous iron preserves iron stores and may hasten the recovery from post-operative anaemia after knee replacement surgery

In unilateral total knee replacement (TKR), perioperative blood loss, low transfusion thresholds and short hospital stay result in patients being discharged with low haemoglobin (Hb). We assessed the effects of perioperative administration of intravenous iron, with or without erythropoietin, plus a restrictive transfusion threshold (Hb < 80 g L(-1)) both on transfusion rate and recovery from post-operative anaemia. TRK patients received iron sucrose (2 x 200 mg per 48 h, iv) (Group IVI, n = 129). Patients with admission Hb < 130 g L(-1), also received erythropoietin (1 x 40 000 IU, sc) (Group EPO, n = 19). Perioperative clinical and laboratory data were obtained. Mean Hb loss was 36 g L(-1), but only seven patients were transfused (5%). Pre-operatively, 66 (45%) patients did not have enough stored iron to compensate Hb loss. At post-operative day 30, only 15% were anaemic, 70% of Hb loss and 92% of pre-operative Hb were recovered and ferritin increased by 73 microg L(-1) (P < 0.01), although erythropoietic response was higher in patients receiving erythropoietin (P < 0.05). No adverse effects of iron sucrose or erythropoietin were witnessed. This protocol seems to reduce allogeneic blood transfusion rate and may hasten the recovery from post-operative anaemia in TKR patients, without depleting iron stores. Further studies are needed to ascertain which patients may benefit of extended intravenous iron and/or erythropoietin administration.

Comparative effectiveness of zinc protoporphyrin and hemoglobin concentrations in identifying iron deficiency in a group of low-income, preschool-aged children: practical implications of recent illness

OBJECTIVE

The goal was to assess the influence of recent infection on screening tests for iron depletion (zinc protoporphyrin and hemoglobin) among low-income, preschool-aged children.

METHODS

This cross-sectional study was conducted at community sites and ambulatory care clinics in Hartford, Connecticut, and included 180 preschool-aged children. Iron depletion was defined as serum ferritin levels of < or = 15 microg/L. Recent illness was defined by parent or guardian (caretaker) report or evidence of elevated C-reactive protein concentrations. History of anemia was determined through medical records review. Sensitivity, specificity and positive predictive values of hemoglobin and zinc protoporphyrin were calculated overall and for children with and without recent illness.

RESULTS

At enrollment, more than one half of the children had a recent illness, and 57.5% had a history of anemia. More than one third had iron depletion. Serum ferritin levels were significantly higher among recently ill children. Secondary to recent illness, the positive predictive value of elevated zinc protoporphyrin, but not low hemoglobin, was reduced significantly. Zinc protoporphyrin levels of >69 micromol/mol heme identified significantly more iron-deficient children.

CONCLUSIONS

Compared with anemia, elevated zinc protoporphyrin levels identified significantly more iron-deficient children. Recently ill children were one half as likely to have low serum ferritin levels, compared with children without recent illness. The negative effect of recent illness on the positive predictive value of zinc protoporphyrin when ferritin is used to determine iron status has many practical implications.

Perioperative intravenous iron, with or without erythropoietin, plus restrictive transfusion protocol reduce the need for allogeneic blood after knee replacement surgery

BACKGROUND

Unilateral total knee replacement (TKR) results in a substantial blood loss and 30 to 50 percent of patients receive allogeneic blood transfusion (ABT). Therefore, the effectiveness of a restrictive transfusion trigger (hemoglobin [Hb] level < 8 g/dL) plus stimulation of erythropoiesis was evaluated, with or without blood salvage, for reducing ABT in TKR patients.

STUDY DESIGN AND METHODS

A series of 139 consecutive of primary TKR patients received perioperative iron sucrose (2 x 200 mg/48 hr, intravenously [IV]), plus preoperative erythropoietin (EPO; 1 x 40.000 UI, sc) if preoperative Hb level was less than 130 g per L (Group A). This protocol was applied to another series of 173 consecutive TKR patients who also received postoperative unwashed shed blood (USB) if preoperative Hb level was less than 130 g per L (Group B). Perioperative clinical and laboratory data were gathered.

RESULTS

No adverse effects of iron sucrose, EPO, or USB administration were witnessed, and only 13 patients received ABT overall (4%). No major differences in perioperative blood counts or iron metabolism variables were observed between groups, but stimulation of erythropoiesis seemed to be more pronounced in those patients receiving EPO (p < 0.05). There were no differences in postoperative complications between groups, but length of hospital stay for patients with a preoperative Hb level of less than 130 g per L was shorter in Group B (p < 0.05).

CONCLUSION

This blood saving protocol seems to be effective for reducing ABT in TKR patients. Which patients are more likely to benefit from either perioperative iron administration or selective addition of postoperative blood salvage to pharmacologic treatment, however, needs to be further evaluated.

Lactoferrin decreases pollen antigen-induced allergic airway inflammation in a murine model of asthma

Pollen grains contain reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidases and in contact with mucosal surfaces generate superoxide anion (O2*-). In the presence of iron, O2*- may be converted to more reactive oxygen radicals, such as to H2O2 and/or *OH, which may augment antigen-induced airway inflammation. The aim of the study was to examine the impact of lactoferrin (LF), an iron-binding protein, on ragweed (Ambrosia artemisiifolia) pollen extract (RWE)-induced cellular oxidative stress levels in cultured bronchial epithelial cells and accumulation of inflammatory and mucin-producing cells in airways in a mouse model of allergic airway inflammation. Results show that LF lowered RWE-induced increase in cellular reactive oxygen species (ROS) levels in bronchial epithelial cells. Most importantly, LF significantly decreased accumulation of eosinophils into airways and subepithelium of intranasally challenged, sensitized mice. LF also prevented development of mucin-producing cells. Amb a 1, the major allergenic ragweed pollen antigen lacking NADPH oxidase activity, induced low-grade airway inflammation. When administered along with glucose oxidase (G-ox), a superoxide-generating enzyme, Amb a 1 induced robust airway inflammation, which was significantly lowered by LF. Surprisingly, LF decreased also inflammation caused by Amb a 1 alone. Iron-saturated hololactoferrin had only a marginal effect on RWE-induced cellular ROS levels and RWE- or Amb a 1 plus G-ox-induced inflammation. We postulate that free iron in the airways chemically reduces O2*- to more reactive species which augment antigen-induced inflammation in a mouse model of asthma. Our results suggest the utility of LF in human allergic inflammatory disorders.

Ferrus calcium citrate is absorbed better than iron bisglycinate in patients with Crohn's disease, but not in healthy controls

Our purpose was to compare the absorption of iron bisglycinate and ferrous calcium citrate in volunteers using an oral iron tolerance test. Twenty volunteers, 10 healthy controls and 10 with stable Crohn's disease, agreed to participate in the study. All were given 50 mg of elemental iron as iron bisglycinate or ferrous calcium citrate. Serum iron levels were monitored for 4 hr. After a week, each received the other regimen. Using the area under the curve as indicator, the oral iron absorption test revealed that absorption of iron post-ingestion of ferrous calcium citrate was better than after ingestion of iron bisglycinate for the group as a whole (P < 0.03). Volunteers with Crohn's disease absorbed ferrous calcium citrate better than iron bisglycinate (P=0.005). No difference was noted in the absorption of either preparation by healthy volunteers. Ferrus calcium citrate is apparently more effective than iron bisglycinate in patients with Crohn's disease.

Iron Overload Manifesting as Apparent Exacerbation of Hepatic Graft-versus-Host Disease after Allogeneic Hematopoietic Stem Cell Transplantation

Iron overload presenting as exacerbation of hepatic graft-versus-host disease (GVHD) after allogeneic hematopoietic stem cell transplantation has not been previously described. We report 6 patients with established hepatic GVHD in whom iron overload (median serum ferritin, 7231 mug/dL; median transferrin saturation, 77%) resulting from a lifetime median of 20 units of packed red blood cell transfusions was manifested by worsening of liver function. Liver biopsies performed in 4 patients confirmed severe iron overload and also hepatic GVHD. Analysis for the C282Y and H63D hemochromatosis gene mutation was negative for the homozygous state in all 6 patients. Erythropoietin-assisted phlebotomy resulted in normalization of liver function at a median of 7 months and of serum ferritin at a median of 11 months. Immunosuppressive therapy was successfully tapered in all 4 patients who completed the phlebotomy program, and this supported the impression that iron overload, rather than GVHD, was the principal cause of liver dysfunction. At a median follow-up of 50 months (range, 18-76 months) from the transplantation and 25 months (range, 5-36 months) from ferritin normalization, all 4 patients require maintenance phlebotomy. We conclude that iron overload can mimic GVHD exacerbation, thus resulting in unnecessary continuation or intensification of immunosuppressive therapy for GVHD, and that maintenance phlebotomy is necessary after successful iron-reduction therapy.

Hereditary hemochromatosis: genetic complexity and new diagnostic approaches

Since the discovery of the hemochromatosis gene (HFE) in 1996, several novel gene defects have been detected, explaining the mechanism and diversity of iron-overload diseases. At least 4 main types of hereditary hemochromatosis (HH) have been identified. Surprisingly, genes involved in HH encode for proteins that all affect pathways centered around liver hepcidin synthesis and its interaction with ferroportin, an iron exporter in enterocytes and macrophages. Hepcidin concentrations in urine negatively correlate with the severity of HH. Cytokine-mediated increases in hepcidin appear to be an important causative factor in anemia of inflammation, which is characterized by sequestration of iron in the macrophage system. For clinicians, the challenge is now to diagnose HH before irreversible damage develops and, at the same time, to distinguish progressive iron overload from increasingly common diseases with only moderately increased body iron stores, such as the metabolic syndrome. Understanding the molecular regulation of iron homeostasis may be helpful in designing innovative and reliable DNA and protein tests for diagnosis. Subsequently, evidence-based diagnostic strategies must be developed, using both conventional and innovative laboratory tests, to differentiate between the various causes of distortions of iron metabolism. This review describes new insights in mechanisms of iron overload, which are needed to understand new developments in diagnostic medicine.

Use of the oral chelator deferiprone in the treatment of iron overload in patients with Hb H disease

Seventeen non-transfusion-dependent Chinese haemoglobin H (Hb H) disease patients (age 29-76 years) with serum ferritin >900 microg/l were treated with deferiprone for up to 18 months. One patient withdrew and data from 16 patients were analysed. Sixteen other Hb H patients with ferritin <900 microg/l, matched for age and genotype, acted as controls. Treatment was well tolerated except for mild arthralgia. Serum ferritin fell with treatment, reaching significance at 6 and 18 months (from 1492.3 +/- 901.4 to 519.4 +/- 405.4 microg/l at 18 months, P = 0.0008). Nine of 16 patients had levels below 397 microg/l before 18 months. Serum ferritin remained stable 6 months after stopping treatment. In contrast, there was no change in ferritin levels in the control group. Magnetic resonance imaging was used for measurement of liver iron content. Spin echo T(1)-signal intensity ratio (T(1)-SIR) and gradient echo T(2)-signal intensity ratio (T(2)-SIR) increased with treatment. T(2)-SIR rose from 0.17 +/- 0.08 pretreatment to 0.58 +/- 0.50 at 2 years (P = 0.0055). Improvement occurred in 12 of 16 patients, reaching normal in three patients. Using echocardiography, peak early diastolic : late diastolic blood flow (E/A) remained unchanged with treatment, but isovolumic relaxation time (IVRT) was prolonged at 2 years indicating mild impairment of diastolic function. All systolic function parameters were normal. A longer treatment period is desirable to demonstrate improvement in cardiac function.

Iron overload is a major risk factor for severe infection after autologous stem cell transplantation: a study of 367 myeloma patients

We evaluated the risk factors for infection of 367 consecutive myeloma patients who underwent high-dose melphalan and autologous stem cell transplantation (ASCT). Examination of bone marrow iron stores (BMIS) prior to ASCT was used to evaluate body iron stores. Other variables included age, sex, active smoking, myeloma remission status, severity of mucositis and duration of severe neutropenia post-ASCT (<100 absolute neutrophils counts (ANC)/microl). Median age was 56 years; 61% of patients were males. 140 episodes of severe infections occurred in 116 patients, including bacteremia (73), pneumonia (40), severe colitis (25) and bacteremia with septic shock (two). The infection incidence per 1,000 days at risk was 45.2. Pre-ASCT risk factors for severe infection by univariate analysis were increased BMIS (OR=2.686; 95% CI 1.707-4.226; P<0.0001), smoking (OR=1.565; 95% CI 1.005-2.437; P=0.0474) and male gender (OR=1.624; 95% CI 1.019-2.589; P=0.0414). Increased BMIS (OR=2.716; 95% CI 1.720-4.287; P<0.0001) and smoking (OR=1.714; 95% CI 1.081-2.718; P=0.022) remained significant by multivariate analysis. Duration of ANC <100 micro/l (OR=1.129; 95% CI 1.039-1.226; P=0.0069 and OR=1.127; 95% CI 1.038-1.224; P=0.0045 by both univariate and multivariate analysis, respectively) was the only post-ASCT risk factor for infection. Increased pre-transplant BMIS and smoking are significant predictors of severe infection after myeloablative chemotherapy followed by ASCT in myeloma patients.

When normal is not: The dilemma of interpreting laboratory averages of bioactive molecules subject to heterogeneous regulatory feedback and epigenetic mosaicism

Complex regulatory systems control the levels of many bioactive molecules in the serum. These systems involve the integration of feedback responses from numerous tissues. End-organs and tissues can manifest epigenetic mosaicism, particularly with aging or disease states. We propose that an isolated lab value may reflect a blended average of inhomogeneous feedback responses from target tissues in various states of dysfunction. Reliance on such data may underestimate the state of systemic dysfunction. Yet in clinical practice, normal serum levels of a given molecule and its associated regulatory machinery are often assumed to reflect normal body homeostasis and tissue function. Organism-wide integration of abnormally high and low levels of bioactivity of a molecule in different tissues may yield apparently normal serum values of the bioactive molecule and known components of its regulatory system. We specifically discuss thyroid hormone regulation and function as a case example. Epigenetic reprogramming of either regulatory loops or tissue responses represents another way in which normal serum levels of the molecule may obscure target-organ dysfunction. The proposed idea has broad implications for disease pathogenesis, diagnosis, and therapies. A model where individual tissues employ illegitimate signaling to subvert the concerns of the organism as a whole is also proposed.

Hemosiderin deposits in chronic graft-vs.-host disease related myopathy

Chronic graft-vs.-host disease (cGVHD) occurs in 20-50% of patients who survive for at least 100 d after allogeneic stem cell transplantation (SCT). cGVHD includes scleroderma-like skin changes, chronic cholangitis, obstructive lung disease and general wasting syndrome. Polymyositis or myopathy are rare manifestations of cGVHD with approximately 40 reported cases. Polymyositis accompanied by hemosiderin deposits in cGVHD has been reported only once, and there are no reports on lipofuscin deposits in skeletal muscle cells in cGVHD. We report here on a 56-yr-old male who underwent allogeneic SCT in 1999 for osteomyelofibrosis and progressive hematopoietic insufficiency. In February 2004, the patient was hospitalized for progressive muscular weakness with loss of the ability to walk. Laboratory tests demonstrated normal values for serum creatine kinase, aldolase and lactic dehydrogenase; the ferritin level was highly elevated. The femoral muscle biopsy showed mostly perifascicular atrophy as well as numerous subsarcolemmal hemosiderin and lipofuscin deposits. Intravenous administration of the chelating agent deferoxamine was ineffective. Three weeks later the patient died of aspiration pneumonia. Interestingly, autopsy disclosed moderate hemosiderin deposits in the liver, the organ usually involved in hemosiderosis.

Benefits and risks of iron therapy for chronic anaemias

Iron is used widely for the treatment of anaemias with iron-restricted erythropoiesis. This intervention can be both beneficial and detrimental depending on the type of the underlying process. While in iron deficiency anaemia (IDA), the most frequent anaemia in the world, iron is the therapy of choice, this intervention can be harmful in the anaemia of chronic disease or anaemia associated with renal failure, the most common anaemias in hospitalized adult patients in Western countries. Iron is able to negatively affect cell-mediated immune effector mechanisms directed against invading microorganisms and tumour cells while at the same time, as an essential nutrient, it can stimulate the proliferation of these unwanted cells. In addition, iron catalyses the formation of toxic radicals leading to tissue damage or the promotion of cardiovascular events. Thus, it is essential to correctly diagnose the precise cause of anaemia and to consider the benefits and hazards of targeted iron therapy.

Iron, oxidative stress and human health

The amount of iron within the cell is carefully regulated in order to provide an adequate level of the micronutrient while preventing its accumulation to toxic levels. Iron excess is believed to generate oxidative stress, understood as an increase in the steady state concentration of oxygen radical intermediates. The main aspects of cellular metabolism of iron, with special emphasis on the role of iron with respect to oxidative damage to lipid membranes, are briefly reviewed here. Both in vitro and in vivo models are examined. Finally, a discussion of iron overload and its impact on human health is included. Overall, further studies are required to assess more effective means to limit iron-dependent damage, by minimizing the formation and release of free radicals in tissues when the cellular iron steady state concentration is increased either as a consequence of disease or by therapeutic iron supplementation.

Hemojuvelin is essential for dietary iron sensing, and its mutation leads to severe iron overload

Iron homeostasis plays a critical role in many physiological processes, notably synthesis of heme proteins. Dietary iron sensing and inflammation converge in the control of iron absorption and retention by regulating the expression of hepcidin, a regulator of the iron exporter ferroportin. Human mutations in the glycosylphosphatidylinositol-anchored protein hemojuvelin (HJV; also known as RGMc and HFE2) cause juvenile hemochromatosis, a severe iron overload disease, but the way in which HJV intersects with the iron regulatory network has been unclear. Here we show that, within the liver, mouse Hjv is selectively expressed by periportal hepatocytes and also that Hjv-mutant mice exhibit iron overload as well as a dramatic decrease in hepcidin expression. Our findings define a key role for Hjv in dietary iron sensing and also reveal that cytokine-induced inflammation regulates hepcidin expression through an Hjv-independent pathway.