Iron Deposition In Tissues Research Articles

Suppression of Hepcidin Expression and Iron Overload Mediate Salmonella Susceptibility in Ankyrin 1 ENU-Induced Mutant

Salmonella, a ubiquitous Gram-negative intracellular bacterium, is a food borne pathogen that infects a broad range of hosts. Infection with Salmonella Typhimurium in mice is a broadly recognized experimental model resembling typhoid fever in humans. Using a N-ethyl-N-nitrosurea (ENU) mutagenesis recessive screen, we report the identification of Ity16 (Immunity to Typhimurium locus 16), a locus responsible for increased susceptibility to infection. The position of Ity16 was refined on chromosome 8 and a nonsense mutation was identified in the ankyrin 1 (Ank1) gene. ANK1 plays an important role in the formation and stabilization of the red cell cytoskeleton. The Ank1Ity16/Ity16 mutation causes severe hemolytic anemia in uninfected mice resulting in splenomegaly, hyperbilirubinemia, jaundice, extramedullary erythropoiesis and iron overload in liver and kidneys. Ank1Ity16/Ity16 mutant mice demonstrated low levels of hepcidin (Hamp) expression and significant increases in the expression of the growth differentiation factor 15 (Gdf15), erythropoietin (Epo) and heme oxygenase 1 (Hmox1) exacerbating extramedullary erythropoiesis, tissue iron deposition and splenomegaly. As the infection progresses in Ank1Ity16/Ity16, the anemia worsens and bacterial load were high in liver and kidneys compared to wild type mice. Heterozygous Ank1+/Ity16 mice were also more susceptible to Salmonella infection although to a lesser extent than Ank1Ity16/Ity16 and they did not inherently present anemia and splenomegaly. During infection, iron accumulated in the kidneys of Ank1+/Ity16 mice where bacterial loads were high compared to littermate controls. The critical role of HAMP in the host response to Salmonella infection was validated by showing increased susceptibility to infection in Hamp-deficient mice and significant survival benefits in Ank1 +/Ity16 heterozygous mice treated with HAMP peptide. This study illustrates that the regulation of Hamp and iron balance are crucial in the host response to Salmonella infection in Ank1 mutants.

Evaluation of a novel oral iron chelator 1-(N-acetyl-6-aminohexyl)-3-hydroxypyridin-4-one (CM1) for treatment of iron overload in mice

Desferrioxamine (DFO), deferiprone (DFP) and deferasirox (DFX) are promising effective iron chelators for the treatment of iron overload in b-thalassemia patients; nonetheless, their side effects have also been reported. 3-Hydroxypyridinone derivatives are being developed as a safer new chelator and in combined chelation therapy. We evaluated the iron-chelating activity of 1-(N-acetyl-6-aminohexyl)-3-hydroxypyridin-4-one (CM1) in iron-loaded C57BL6 mice. The feeding of a ferrocene-supplemented diet (Fe diet) to mice resulted in iron overload, detectable plasma nontransferrin-bound iron (NTBI) and labile plasma iron (LPI), and increases of red cell membrane iron, plasma malondialdehyde (MDA) and excessive tissue iron deposits. Like DFP, the CM1 lowered the levels of the membrane non-heme iron, the NTBI and LPI (p

Iron chelation therapy in patients with transfusion‐dependent myelodysplastic syndrome

Iron chelation therapy in patients with transfusion‐dependent myelodysplastic syndrome

High-fat, high-fructose diet induces hepatic iron overload via a hepcidin-independent mechanism prior to the onset of liver steatosis and insulin resistance in mice

ObjectiveExcess iron deposition in tissues leads to increased oxidative stress. The clinical observation that non-alcoholic fatty liver disease (NAFLD) is frequently associated with hepatic iron overload (HIO) indicates that iron-induced oxidative stress may be related to NAFLD pathology. Decreased expression of hepcidin, a hepatic hormone that suppresses dietary iron absorption in the duodenum, is frequently observed in NAFLD patients and has been postulated to be a cause of HIO. Materials/MethodsBecause dietary fat and fructose intake play roles in the onset of NAFLD, we fed C57BL/6J mice a high-fat, high-fructose (HFHFr) diet for 16weeks to study the relationship between hepatic iron content and NAFLD. ResultsWithin 4weeks after the start of the experiment, the mice exhibited significant increases in hepatic free fatty acid (FFA) content, serum insulin levels, and the homeostasis model assessment of insulin resistance. Interestingly, hepatic iron content and oxidative stress significantly increased with the HFHFr diet 2weeks earlier than hepatic FFA accumulation and decreased insulin sensitivity. Moreover, hepatic hepcidin expression was significantly downregulated, as is also observed in NAFLD patients, but much later than the onset of HIO. ConclusionsAccordingly, our data demonstrated that HIO may have a pathogenic role in the onset of liver steatosis and insulin resistance. Moreover, distinct mechanisms, in addition to hepcidin, may underlie NAFLD-related HIO. These data suggest that the HFHFr diet can be used for establishing a suitable model to study the precise mechanism of HIO in NAFLD patients.

Mechanisms of Mammalian Iron Homeostasis

Iron is vital for almost all organisms because of its ability to donate and accept electrons with relative ease. It serves as a cofactor for many proteins and enzymes necessary for oxygen and energy metabolism, as well as for several other essential processes. Mammalian cells utilize multiple mechanisms to acquire iron. Disruption of iron homeostasis is associated with various human diseases: iron deficiency resulting from defects in the acquisition or distribution of the metal causes anemia, whereas iron surfeit resulting from excessive iron absorption or defective utilization causes abnormal tissue iron deposition, leading to oxidative damage. Mammals utilize distinct mechanisms to regulate iron homeostasis at the systemic and cellular levels. These involve the hormone hepcidin and iron regulatory proteins, which collectively ensure iron balance. This review outlines recent advances in iron regulatory pathways as well as in mechanisms underlying intracellular iron trafficking, an important but less studied area of mammalian iron homeostasis.

Management of Transfusion-Related Iron Overload in Patients With Myelodysplastic Syndromes

Anemia is a common symptom for patients with myelodysplastic syndromes (MDS), a spectrum of hematopoietic malignancies characterized by ineffective hematopoiesis; 90% of these patients will become transfusion dependent (TD). Because of the closed nature of iron metabolism, the repeated input of packed red blood cells during transfusions inevitably leads to iron overload. Iron overload can cause iron-related toxicity as well as end-organ damage from iron deposition in tissues. Studies have shown that patients with MDS who are TD have shorter overall survival, shorter leukemia-free survival, and higher healthcare costs compared with patients who are not TD, suggesting that iron overload has a significant clinical and economic impact. Iron chelation therapy can bind and eliminate free iron from the body. Although studies in genetic anemias have shown improved clinical outcomes, clinical trials with patients with MDS are ongoing. Because iron chelation therapy can be toxic, the risks, benefits, and therapy-related costs must be weighed for each patient.

Relationship between Plasma Ferritin Level and Siderocyte Number in Splenectomizedβ-Thalassemia/HbE Patients

Introduction. In iron overload status, excess iron deposits in reticuloendothelial cells and tissues and can be detected using Prussian blue staining. The aim of this paper was to investigate the relationship between siderocyte numbers and plasma ferritin levels (a practically standard marker of iron overload) in the blood of the splenectomized and nonsplenectomized β-thalassemia/HbE patients, who are at risk of iron overload. Methods. EDTA blood samples from 64 patients with 35 splenectomized and 29 nonsplenectomized β-thalassemia/HbE patients, who received regular blood transfusions, and 20 normal individuals were investigated for siderocyte numbers, plasma ferritin levels, and complete blood counts. Results. The average percent siderocytes in splenectomized and nonsplenectomized β-thalassemia/HbE patients were 11.5% and 0.08%, respectively, and plasma ferritin levels of 2,332 μg/L and 1,279 μg/L, respectively. Percent siderocytes showed a good correlation with plasma ferritin levels only in splenectomized patients (r = 0.69, P < 0.001). A receiver operating curve analysis from splenectomized patients' data indicated that siderocytes at 3% cut-off are the best predictor for plasma ferritin level ≥1,000 μg/L with 92.9% sensitivity and 42.9% specificity. Conclusion. Circulating siderocyte numbers can be used as a screening test for the assessment of the iron overload in splenectomized β-thalassemia/HbE patients in the place where serum ferritin is not available.

Overview of Current and Emerging Issues in Endocrinological Complications of Thalassaemia

Clinical advances in the treatment of thalassaemia major (TM) patients have helped to increase substantially the life expectancy of patients. The TM patients today represent the first generation of adult thalassemics. As patients enter puberty, they begin to experience a variety of endocrine abnormalities, presumably the results of chronic anaemia and tissue iron deposition from the chronic transfusion therapy. In patients with TM, the anterior pituitary gland is particularly sensitive to free radical stresses. Recent reports have documented a frequency of severe growth hormone deficiency in 13–32% of adult patients with TM. The prevalence of impaired adrenal function in TM patients has been reported from 0 to 33%, depends on the age of the population studied, although clinical adrenal insufficiency (AI) is rare. Thyroid dysfunction has been observed in 13–60% of patients, but its severity is variable in different series. Acquired central hypothyroidism (CH) is a rare complication.

Liver Iron Concentration Estimates by R2* Are More Robust Than by Ferriscan During Rapid Changes in Iron Burden

Abstract 5296 Introduction:MRI assessment of LIC concentration is increasing utilized as the primary outcome variable of clinical trials for iron chelation. The MRI parameters R2 and R2* can both be used for this purpose but have slightly different sensitivities to the scale and distribution of tissue iron deposits. As a result, these techniques may provide significantly disparate results in any given patient and may diverge following abrupt changes in chelation therapy. It is not practical, nor ethical, to use liver biopsy to validate R2 and R2* LIC measures on a short time scale. Thus, we used calculations of chelator molar efficiency to determine whether predicted changes in LIC were consistent with the known iron balance assessed by transfusional burden and drug consumption. Methods:The Phase II trial of FBS701, a novel oral iron chelator, measured LIC by both R2 and R2* at screening, 12 weeks, and 24 weeks of therapy; nine thalassemia centers participated in 7 countries. 51 individuals completed 24 weeks of treatment. Liver R2 was collected and analyzed using a FDA-approved protocol and a commercial vendor (Ferriscan Resonance Health, Australia). Liver R2* was measured using gradient echo sequences with minimum echo times ranging from 1.0–1.2 ms. All gradient echo images were transferred to a central core laboratory for R2* calculation using a three component decay model (exponential + offset). Only patients with LIC values between 3 and 30 mg/g by Ferriscan LIC were allowed to participate. Transfusional iron burden was calculated from transfusional volumes documented for six months prior to entering the study and corrected for hematocrit. Change in total body iron was calculated using the Angelucci equation. Chelator efficiency was calculated using the net change in body iron concentration by drug consumption, calculated on a molar basis, to yield a unit-less number; drug concentration was divided by two to account for the chelator-iron stoichiometry.Observed changes in LIC were judged to be erroneous if they produced an estimated chelator efficiency greater than one or less than zero. We also assume that the efficiency between 0–12 weeks and 12–24 weeks should be comparable; the variance between these two values was used as an independent metric of Ferriscan, robustness for LIC measurement. Results:Figure 1 demonstrates the calculated chelator efficiency from 12–24 weeks versus 0–12 weeks, using LIC values calculated by Ferriscan(open circles) and by R2* (solid dots). The solid line indicates the line of identity and the inset box represents the physiologically possible range. 19/95 Ferriscan LIC measurements were physiologically impossible compared with 5/95 R2* LIC measurements (p=0.004 by Fischer’s exact test). Ferriscan 12–24 week efficiency measurements were uncorrelated with Ferriscan 0–12 week measurements and generally strayed a greater distance from the line of identity, with a three-fold larger mean-squared error (0.375 versus 0.126) than for efficiencies calculated using R2*. [Display omitted] Discussion:Both R2 and R2* are biopsy-validated, clinically accepted tools for noninvasive LIC estimation and can be used to track liver iron on a long-term basis. However, the ability of these techniques to accurately track short-term changes (below 1 year) has never been studied; such changes may be important for rapid dose-titration. In this study, Ferriscan LIC estimates were inconsistent with measured iron-balance, producing many nonphysiologic estimates of chelator efficiency and poor consistency between observations at three-month intervals. It is not known whether this represents an intrinsic property of R2 measurements, caused by undue sensitivity to microscopic iron particle distribution, or a limitation specific to the Ferriscan processing. However, given the previously published success of the Ferriscan technique with respect to liver biopsy when assessed on longer time-scales, we believe that these data represent a disequilibrium phenomenon, i.e., that R2 measurements are transiently inaccurate following an abrupt chelation change. Longer-term studies will be necessary to test this hypothesis. Nonetheless, caution should be used in trying to interpret Ferriscan results at intervals of six months or less. R2* LIC measurements are intrinsically less sensitive to changes in tissue iron distribution and more accurate reflections of iron balance at shorter time intervals. Disclosures:Wood:Novartis: Research Funding; Ferrokin Biosciences: Consultancy; Cooleys Anemia Foundation: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Jones:Ferrokin BioSciences: Employment. Rienhoff:Ferrokin BioSciences: Employment, Equity Ownership. Neufeld:Ferrokin BioSciences: Research Funding; Novartis: Research Funding.

MRI assessment of iron deposition in multiple sclerosis

Iron deposition in the human brain tissue occurs in the process of normal aging and in many neurodegenerative diseases. Elevated iron levels in certain brain regions are also an increasingly recognized finding in multiple sclerosis (MS). The exact mechanism(s) for this phenomenon and its implication in terms of pathophysiology and clinical significance are still largely unknown and debated. Reliable methods to exactly quantify brain iron are a first step to clarify these issues. Therefore, the aim of this review is to present currently available magnetic resonance imaging (MRI) techniques for the assessment of brain iron. These include relaxation time mapping, phase imaging, susceptibility-weighted imaging, susceptibility mapping, magnetic field correlation imaging, and direct saturation imaging. After discussing their advantages and disadvantages, existing MRI clinical correlations with brain iron concentration in MS are summarized and future research directions are shown.

Establishment of Secondary Iron Overloaded Mouse Model: Evaluation of Cardiac Function and Analysis According to Iron Concentration

Periodic blood transfusion can lead to secondary iron overload in patients with hematologic and oncologic diseases. Iron overload can result in iron deposition in heart tissue, which decreases cardiac function and can ultimately lead to death due to dilated cardiomyopathy and cardiac failure. In this study, we established murine model of secondary iron overload, studied the changes in cardiac function with echocardiography, and examined the histopathologic changes. Three experimental groups of the six week-old C57/BL mice (H-2(b)) were injected intraperitoneally with 10 mg of iron dextran daily 5 days a week for 2, 4, and 6 weeks. Cumulative doses of iron for the three experimental groups were 100, 200, and 300 mg, while the control groups were injected with the same amounts of phosphate-buffered saline. We studied the cardiac function under anesthesia with echocardiography using a GE Vivid7 Dimension system. Plasma iron levels and liver iron contents were measured. The hearts and livers were harvested and stained with H&E and Perls Prussian blue for iron, and the levels of iron deposit were examined. We assessed the cardiac measurements after adjustment for weight. On echocardiography, thicknesses of the interventricular septum and posterior ventricular wall (PS) during diastole showed correlation with the amount of iron deposit (P < 0.01). End-diastolic volume showed dilatation of the left ventricle in the 300 mg group (P < 0.01). Changes in the fractional shortening were not statistically significant (P = 0.07). Plasma iron levels and liver iron contents were increased proportionally according to the amount of iron loaded. The histopathologic findings of PS and liver showed higher grade of iron deposit proportional to the cumulated iron dose. In this study, we present an animal model which helps understand the cardiac function changes in patients with secondary iron overload due to repeated blood transfusions. Our results may help characterize the pathophysiologic features of cardiomyopathy in patients with secondary iron overload, and our model may be applied to in vivo iron-chelating therapy studies.

Combined R2* and Diffusion Tensor Imaging Changes in the Substantia Nigra in Parkinson's Disease

Recent magnetic resonance imaging studies suggest an increased transverse relaxation rate and reduced diffusion tensor imaging fractional anisotropy values in the substantia nigra in Parkinson's disease. The transverse relaxation rate and fractional anisotropy changes may reflect different aspects of Parkinson's disease-related pathological processes (ie, tissue iron deposition and microstructure disorganization). This study investigated the combined changes of transverse relaxation rate and fractional anisotropy in the substantia nigra in Parkinson's disease. High-resolution magnetic resonance imaging (T2-weighted, T2*, and diffusion tensor imaging) were obtained from 16 Parkinson's disease patients and 16 controls. Bilateral substantia nigras were delineated manually on T2-weighted images and coregistered to transverse relaxation rate and fractional anisotropy maps. The mean transverse relaxation rate and fractional anisotropy values in each substantia nigra were then calculated and compared between Parkinson's disease subjects and controls. Logistic regression, followed by receiver operating characteristic curve analysis, was employed to investigate the sensitivity and specificity of the combined measures for differentiating Parkinson's disease subjects from controls. Compared with controls, Parkinson's disease subjects demonstrated increased transverse relaxation rate (P<.0001) and reduced fractional anisotropy (P=.0365) in the substantia nigra. There was no significant correlation between transverse relaxation rate and fractional anisotropy values. Logistic regression analyses indicated that the combined use of transverse relaxation rate and fractional anisotropy values provides excellent discrimination between Parkinson's disease subjects and controls (c-statistic=0.996) compared with transverse relaxation rate (c-statistic=0.930) or fractional anisotropy (c-statistic=0.742) alone. This study shows that the combined use of transverse relaxation rate and fractional anisotropy measures in the substantia nigra of Parkinson's disease enhances sensitivity and specificity in differentiating Parkinson's disease from controls. Further studies are warranted to evaluate the pathophysiological correlations of these magnetic resonance imaging measurements and their effectiveness in assisting in diagnosing Parkinson's disease and following its progression.

Calcium channels and iron uptake into the heart

Iron overload can lead to iron deposits in many tissues, particularly in the heart. It has also been shown to be associated with elevated oxidative stress in tissues. Elevated cardiac iron deposits can lead to iron overload cardiomyopathy, a condition which provokes mortality due to heart failure in iron-overloaded patients. Currently, the mechanism of iron uptake into cardiomyocytes is still not clearly understood. Growing evidence suggests L-type Ca(2+) channels (LTCCs) as a possible pathway for ferrous iron (Fe(2+)) uptake into cardiomyocytes under iron overload conditions. Nevertheless, controversy still exists since some findings on pharmacological interventions and those using different cell types do not support LTCC's role as a portal for iron uptake in cardiac cells. Recently, T-type Ca(2+) channels (TTCC) have been shown to play an important role in the diseased heart. Although TTCC and iron uptake in cardiomyocytes has not been investigated greatly, a recent finding indicated that TTCC could be an important portal in thalassemic hearts. In this review, comprehensive findings collected from previous studies as well as a discussion of the controversy regarding iron uptake mechanisms into cardiomyocytes via calcium channels are presented with the hope that understanding the cellular iron uptake mechanism in cardiomyocytes will lead to improved treatment and prevention strategies, particularly in iron-overloaded patients.

A Case of Pulmonary Siderosis Mimicking Metastatic Lung Cancer

Pulmonary siderosis is a pneumoconiosis caused by chronic iron inhalation. A diagnosis of pulmonary siderosis is based on a patient history of iron inhalation, on chest radiographic findings, and on accumulation of iron oxide in macrophages within the lung. A typical radiographic finding of pulmonary siderosis includes ill-defined micronodules that are diffusely distributed in the lung. We experienced a 52-year-woman with a 1.3×1.5-cm mass in the left upper lobe with multiple nodules in both lungs. Because the radiographic findings were atypical, we conducted a video-assisted thorascopic lung biopsy procedure to exclude the diagnosis of metastatic lung cancer. After confirming iron deposition in the lung tissue and knowing the patient's occupational history of welding iron, we concluded that this was a case of pulmonary siderosis.

Iron-Induced Cardiac Damage: Role of Apoptosis and Deferasirox Intervention

Excess cardiac iron levels are associated with cardiac damage and can result in increased morbidity and mortality. Here, we hypothesize that elevations in tissue iron can activate caspase-dependent signaling, which leads to increased cardiac apoptosis and fibrosis, and that these alterations can be attenuated by iron chelation. Using an iron-overloaded gerbil model, we show that increased cardiac iron is associated with reduced activation of Akt (Ser473 and Thr308), diminished phosphorylation of the proapoptotic regulator Bad (Ser136), and an increased Bax/Bcl-2 ratio. These iron-overload-induced alterations in Akt/Bad phosphorylation and Bax/Bcl-2 ratio were coupled with increased activation of the downstream caspase-9 (40/38- and 17-kDa fragments) and apoptosis executioner caspase-3 (19- and 17-kDa fragments), which were accompanied by evidence of elevated cytoskeletal α-fodrin cleavage (150- and 120-kDa fragments), discontinuity of myocardial membrane dystrophin immunoreactivity, increases in the number of terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL)-positive cells (nucleic DNA fragmentation), and cardiac fibrosis. We demonstrate that the administration of deferasirox, a tridentate iron chelator, is associated with diminished tissue iron deposition, attenuated activation of caspases, reduced α-fodrin cleavage, improved membrane integrity, decreased TUNEL reactivity, and attenuated cardiac fibrosis. These results suggest that the activation of caspase-dependent signaling may play a role in the development of iron-induced cardiac apoptosis and fibrosis, and deferasirox, via a reduction in cardiac tissue iron levels, may be useful for decreasing the extent of iron-induced cardiac damage.

Adiponectin-Mediated Heme Oxygenase-1 Induction Protects Against Iron-Induced Liver Injury via a PPARα-Dependent Mechanism

Protective effects of adiponectin (APN; an adipocytokine) were shown against various oxidative challenges; however, its therapeutic implications and the mechanisms underlying hepatic iron overload remain unclear. Herein, we show that the deleterious effects of iron dextran on liver function and iron deposition were significantly reversed by adiponectin gene therapy, which was accompanied by AMP-activated protein kinase (AMPK) phosphorylation and heme oxygenase (HO)-1 induction. Furthermore, AMPK-mediated peroxisome proliferator-activated receptor-α (PPARα) activation by APN was ascribable to HO-1 induction. Additionally, we revealed direct transcriptional regulation of HO-1 by the binding of PPARα to a PPAR-responsive element (PPRE) by various experimental assessments. Interestingly, overexpression of HO-1 in hepatocytes mimicked the protective effect of APN in attenuating iron-mediated injury, whereas it was abolished by SnPP and small interfering HO-1. Furthermore, bilirubin, the end-product of the HO-1 reaction, but not CO, protected hepatocytes from iron dextran-mediated caspase activation. Herein, we demonstrate a novel functional PPRE in the promoter regions of HO-1, and APN-mediated HO-1 induction elicited an antiapoptotic effect and a decrease in iron deposition in hepatocytes subjected to iron challenge.

Transfusion of red blood cells after prolonged storage produces harmful effects that are mediated by iron and inflammation

Although red blood cell (RBC) transfusions can be lifesaving, they are not without risk. In critically ill patients, RBC transfusions are associated with increased morbidity and mortality, which may increase with prolonged RBC storage before transfusion. The mechanisms responsible remain unknown. We hypothesized that acute clearance of a subset of damaged, stored RBCs delivers large amounts of iron to the monocyte/macrophage system, inducing inflammation. To test this in a well-controlled setting, we used a murine RBC storage and transfusion model to show that the transfusion of stored RBCs, or washed stored RBCs, increases plasma nontransferrin bound iron (NTBI), produces acute tissue iron deposition, and initiates inflammation. In contrast, the transfusion of fresh RBCs, or the infusion of stored RBC-derived supernatant, ghosts, or stroma-free lysate, does not produce these effects. Furthermore, the insult induced by transfusion of stored RBC synergizes with subclinical endotoxinemia producing clinically overt signs and symptoms. The increased plasma NTBI also enhances bacterial growth in vitro. Taken together, these results suggest that, in a mouse model, the cellular component of leukoreduced, stored RBC units contributes to the harmful effects of RBC transfusion that occur after prolonged storage. Nonetheless, these findings must be confirmed by prospective human studies.

T2* Magnetic Resonance Imaging Sequences Reflect Brain Tissue Iron Deposition Following Intracerebral Hemorrhage

To examine the utility of magnetic resonance imaging (MRI) T2* sequences as a measure of iron overload in the brain following intracerebral hemorrhage (ICH). We examined the time course of T2* changes in the brain around intracerebral hemorrhages in a series of patients. We also performed a series of experiments in an animal model of ICH, examining the time course of T2* changes along with correlation of these changes with histological markers of ferric iron deposition. We found that T2* changes in the brain occur with increasing intensity and spatial distribution over a three month period. Experimental ICH in the rat model induces similar changes, and these changes correlate tightly with histological markers of ferric iron deposition. MRI T2* changes after ICH can be used to measure the degree of iron overload in the brain. The T2* sequence may be useful as a measure of interventions aimed at reducing ICH-related brain injury by reducing iron deposition.

Precocious bilateral hip joint osteoarthritis is a “form-fruste” of the arthropathy of Hereditary Haemochromatosis

Osteoarthritis (OA) of the hip joint is a common disorder, especially in aging peoples of Caucasian descent. Hip OA like OA in other joints is heterogeneous and may manifest in early or late adult life. The aetiology of early onset (precocious) bilateral hip OA is poorly understood, but the clinical and radiological characteristics of this form of OA suggest that chondral resorption due to biochemical or metabolic factors is likely to be of pre-eminent importance. The hip arthropathy which occurs in Hereditary Haemochromatosis (HH) and the ostensibly idiopathic precocious bilateral concentric form of hip OA are virtually indistinguishable. Accordingly, the possibility exists that the causal factors for these conditions may be very similar. On the basis of this premise and in the light of the finding in a small observational study that HFE gene mutations are very common in precocious bilateral hip OA (100% amongst 8 sequentially collected patients), it is hypothesised that precocious bilateral hip OA is a "form-fruste" of the arthropathy of HH in which HFE gene mutation mediated articular iron deposition in hip joint tissues may be of pivotal pathogenetic importance. Confirmation of this hypothesis could have implications for the prevention and strategic medical management of this form of OA.

Chronic Deferasirox Administration Decreases Hepatic Oxidative Stress and Apoptosis in the Iron Overloaded Gerbil.

Abstract 1996Poster Board I-1018 Background:Iron overload occurs under conditions such as primary (hereditary) hemochromatosis and secondary iron overload (hemosiderosis) and is associated with an increased risk of developing liver fibrosis, cirrhosis, and hepatocellular carcinoma. Deferasirox is a novel oral chelator with high iron-binding potency and selectivity. Here we investigate the ability of deferasirox to remove excessive hepatic iron and prevent or reverse iron induced hepatic injury. Methods:Adult male Mongolian Gerbils were randomly divided into three groups: control, iron overload, and iron overload + deferasirox treatment (n = 8 / group). Iron overload animals received iron dextran 100mg/kg i.p /5d for 10 wks while deferasirox was given 100mg/kg/d p.o for 1-,3-, or 9- months. Hepatic iron levels were determined by inductively coupled plasma atomic emission spectrometry and Prussian blue staining was performed to examine iron deposition in the corresponding tissues. Immunoblot and immunohistochemical analyses for markers of oxidative stress were employed to assess effects of deferasirox treatment on hepatic protein oxidation and superoxide levels. TUNEL assay was employed to examine the extent of hepatic apoptosis. Results:Compared to the non-treated iron overload group, deferasirox treatment reduced hepatic iron levels by 21.3%, 43.5%, and 47.4% after 1, 3, and 9 months of treatment, respectively (p<0.05). Prussian blue staining and histological analysis detected frequent iron deposition, evidence of hepatic damage, and lipid accumulation in hepatic tissue of the iron overloaded group. Iron deposition was significantly diminished with deferasirox treatment and no evidence of lipid accumulation was observed. Immunoblotting demonstrated that iron overload caused 2- fold increase in hepatic ferritin expression (p< 0.05) which was reduced by 47.5% following three months of deferasirox treatment (p< 0.05). In addition, deferasirox significantly reduced hepatic protein oxidation and superoxide abundance. The percentage of TUNEL-positive nuclei in the deferasirox treated livers was 41.0% lower than that of iron overloaded group (p<0.05). Conclusions:These findings suggest that chronic deferasirox treatment may decrease iron-induced hepatic oxidative stress and apoptosis. Decrease in ROS accumulation in the liver may be the possible mechanism of this protective effect. Further studies are underway to delineate specific mechanisms. Disclosures:No relevant conflicts of interest to declare.