Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P02794 (ferritin)
 17,525 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Deferoxamine is a chelating agent that has extended the life expectancy of patients with thalassemia. In the 1980s, many investigators reported otologic and visual toxicity caused by deferoxamine. In July 1999 and 2 years later, the authors performed audiologic and ophthalmologic assessments in 30 transfusion-dependent patients receiving deferoxamine therapy (40-50 mg/kg per dose, subcutaneously for 8-10 hours, 4-7 days per week). In 1999, six patients (20%) had deferoxamine-related hearing impairment (>25 dB), all at high frequencies. Because the authors believed the benefits of chelation therapy outweighed the risk of ototoxicity, the dose of deferoxamine was not reduced. Two years later, the hearing impairment had not progressed in any of the patients. There was no association between ototoxicity and ferritin level. No patients had abnormalities of visual acuity or funduscopy in either 1999 or 2001. Based on this experience, deferoxamine at doses lower than 50 mg/kg/d was safe for the eyes and slightly toxic to the ears. The ototoxicity probably relates to individual susceptibility. Regular monitoring of auditory function and close follow-up of abnormal findings are recommended. According to this limited experience, reducing the dose or withdrawing deferoxamine might not be necessary if the hearing loss is stable in the face of ferritin levels above 2,000 ng/mL. Because of the relatively small patient numbers, more data are needed to confirm these conclusions.
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PMID:Auditory and visual toxicity during deferoxamine therapy in transfusion-dependent patients. 1634 69

Deferoxamine (DFO) therapy has been associated with improved survival of thalassemia patients. However, cardiac disease remains the main cause of death in those patients. In 1995, the oral chelator deferiprone became available for clinical use. We compared the occurrence of cardiac disease in patients treated only with DFO and in those whose therapy was switched to deferiprone during the period of observation, from January 31, 1995, to December 31, 2003. All patients with thalassemia major treated in 7 Italian centers who were born between 1970 and 1993 and who had not experienced a cardiac event prior to January 1995 were included. DFO only was given to 359 patients, and 157 patients received deferiprone for part of the time. A total of 3,610 patient-years were observed on DFO and 750 on deferiprone. At baseline, the 2 groups were comparable for age and sex, while ferritin levels were significantly higher in patients switched to deferiprone. Fifty-two cardiac events, including 10 cardiac deaths, occurred during therapy with DFO. No cardiac events occurred during deferiprone therapy or within at least 18 months after the end of it. In the setting of a natural history study, deferiprone therapy was associated with significantly greater cardiac protection than deferoxamine in patients with thalassemia major.
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PMID:Cardiac morbidity and mortality in deferoxamine- or deferiprone-treated patients with thalassemia major. 1637 63

Desferrioxamine inhibits cortical necrosis in neonatal rats with experimental pneumococcal meningitis, suggesting that iron-induced oxidative damage might be responsible for neuronal damage. We therefore examined the spatial and temporal profile of changes in cortical iron and iron homeostatic proteins during pneumococcal meningitis. Infection was associated with a steady and global increase of non-haem iron in the cortex, particularly in neuronal cell bodies of layer II and V, and in capillary endothelial cells. The non-haem iron increase was associated with induction of haem oxygenase (HO)-1 in neurones, microglia and capillary endothelial cells, whereas HO-2 levels remained unchanged, suggesting that the non-haem iron increase might be the result of HO-1-mediated haem degradation. Indeed, treatment with the haem oxygenase inhibitor tin protoporphyrin (which completely blocked the accumulation of bilirubin detected in HO-1-positive cells) completely prevented the infection-associated non-haem iron increase. The same cells also displayed markedly increased ferritin staining, the increase of which occurred independently of HO activity. At the same time, no increase in DNA/RNA oxidation was observed in infected animals (as assessed by in situ detection of 8-hydroxy[deoxy]guanosine), strongly suggesting that ferritin up-regulation protected the brain from iron-induced oxidative damage. Thus, although pneumococcal meningitis leads to an increase of cortical non-haem iron, protective mechanisms up-regulated in parallel prevent iron-induced oxidative damage. Cortical damage does not appear to be a direct consequence of increased iron, therefore.
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PMID:Induction of haem oxygenase-1 causes cortical non-haem iron increase in experimental pneumococcal meningitis: evidence that concomitant ferritin up-regulation prevents iron-induced oxidative damage. 1711 31

This study was conducted to assess the effect of age, ferritin level, hemoglobin level and chelating agents on the physical growth in thalassemic children and to determine the prevalence of dental caries in thalassemic children. Weight, standing height, sitting height and subischial leg length were measured in 65 children attending the Thalassemia day care center at a tertiary hospital in Delhi. Their mean pre transfusion hemoglobin and ferritin levels over the previous two years were calculated. Dental caries indices, DMFT and DMFS were measured and compared with age matched controls. Weight, standing height, sitting height and subischial leg length expressed as percentage for age in children >or=10 y were significantly lower than those of children < 6 y, and those 6 to 10 y. Mean hemoglobin and ferritin did not affect growth significantly. Sitting height for age in children receiving Desferrioxamine alone or Desferrioxamine with Deferiprone was significantly lower than that of children receiving Deferiprone alone or no chelating agent. Dental caries were significantly higher in thalassemics.
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PMID:Physical growth patterns and dental caries in thalassemia. 1720 3

Iron closely regulates the expression of the Alzheimer's Amyloid Precursor Protein (APP) gene at the level of message translation by a pathway similar to iron control of the translation of the ferritin L- and H mRNAs by Iron-responsive Elements in their 5' untranslated regions (5'UTRs). Using transfection based assays in SH-SY5Y neuroblastoma cells we tested the relative efficiency by which iron, copper and zinc up-regulate IRE activity in the APP 5'UTR. Desferrioxamine (high affinity Fe3+ chelator), (ii) clioquinol (low affinity Fe/Cu/Zn chelator), (iii) piperazine-1 (oral Fe chelator), (iv) VK-28 (oral Fe chelator), were tested for their relative modulation of APP 5' UTR directed translation of a luciferase reporter gene. Iron chelation based therapeutic strategies for slowing the progression of Alzheimer's disease (and other neurological disorders that manifest iron imbalance) are discussed with regard to the relative neural toxic action of each chelator in SH-SY5Y cells and in H4 glioblastoma cells.
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PMID:Metal specificity of an iron-responsive element in Alzheimer's APP mRNA 5'untranslated region, tolerance of SH-SY5Y and H4 neural cells to desferrioxamine, clioquinol, VK-28, and a piperazine chelator. 1744 34

Pores regulate access between ferric-oxy biomineral inside and reductants/chelators outside the ferritin protein nanocage to control iron demineralization rates. The pore helix/loop/helix motifs that are contributed by three subunits unfold independently of the protein cage, as observed by crystallography, Fe removal rates, and CD spectroscopy. Pore unfolding is induced in wild type ferritin by increased temperature or urea (1-10 mM), a physiological urea range, 0.1 mM guanidine, or mutation of conserved pore amino acids. A peptide selected for ferritin pore binding from a combinatorial, heptapeptide library increased the rate of Fe demineralization 3-fold (p<0.001), similarly to a mutation that unfolded the pores. Conjugating the peptide to Desferal (desferrioxamine B mesylate), a chelator in therapeutic use, increased the rates to 8-fold (p<0.001). A second pore binding peptide had the opposite effect and decreased the rate of Fe demineralization 60% (p<0.001). The peptides could have pharmacological uses and may model regulators of ferritin demineralization rates in vivo or peptide regulators of gated pores in membranes. The results emphasize that small peptides can exploit the structural plasticity of protein pores to modulate function.
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PMID:Peptides selected for the protein nanocage pores change the rate of iron recovery from the ferritin mineral. 1778 67

Myelodysplastic syndromes (MDS) are a group of disorders characterized by ineffective hematopoiesis that leads to peripheral cytopenias. Iron overload results from high transfusion requirements and retrospective studies have shown it to be associated with relatively poor survival in a subset of the low risk patients. Recent discoveries have led to the identification of hepcidin as a key regulator of iron metabolism and to the association of non-transferrin bound iron moieties, such as labile plasma iron, with the end organ damage in iron overload states. Currently, there is limited data in evaluating the role of iron chelators in MDS and data from studies in Thalassemia and hemachromostosis have been used to predict ferritin levels above 1000 - 2500 ng/mL and history of 20 blood transfusions as clinical end points for considering iron chelation in MDS. Deferoxamine and deferasirox, the two iron chelators approved for use in the US, have shown efficacy in reducing iron overload in MDS in retrospective studies are now being evaluated for effects on overall survival in prospective studies. On the basis of retrospective data, it is reasonable to offer iron chelation to the lower risk MDS patients requiring frequent transfusions, while monitoring for specific adverse affects in patients on treatment.
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PMID:Iron overload in myelodysplastic syndromes. 1829 18

Most patients with myelodysplastic syndrome eventually become dependent on regular red cell transfusions. This dependency has a negative impact on clinical outcome, primarily because it may be associated with more severe marrow failure. In addition, however, transfusion dependency may involve clinical consequences of chronic anemia and iron overload. Although transfusion iron is primarily taken up by the reticuloendothelial cells, the metal is later redistributed to parenchymal cells. This redistribution is modulated by several factors, including the degree of ineffective erythropoiesis through its suppressive effect on hepcidin production. Body iron status is routinely assessed by serum ferritin and transferrin saturation, but there is a need of reliable tools for locating iron accumulation in patients. Magnetic resonance imaging T2* provides a non-invasive method for detecting and quantifying both liver and myocardial iron overload. Clinical consequences of parenchymal iron overload have been reported not only in thalassemia major, but also in patients with myelodysplastic syndrome. Transfusion-dependent patients with isolated erythroid dysplasia and low risk of leukemic evolution are more likely to develop parenchymal iron overload and its toxicity, and therefore may benefit from chelation therapy. There may also be a benefit of chelation therapy in patients with transfusion iron overload undergoing allogeneic stem cell transplantation. Deferoxamine and deferasirox are currently available for treatment of transfusion iron overload in patients with myelodysplastic syndrome.
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PMID:Clinical relevance of anemia and transfusion iron overload in myelodysplastic syndromes. 1907 76

A multicentre randomized open-label trial was designed to assess the effectiveness of long-term sequential deferiprone-deferoxamine (DFO-DFP) versus DFP alone to treat thalassaemia major (TM). DFP at 75 mg/kg, divided into three oral daily doses, for 4 d/week and DFO by subcutaneous infusion (8-12 h) at 50 mg/kg per day for the remaining 3 d/week was compared with DFP alone at 75 mg/kg, administered 7 d/week during a 5-year follow-up. The main outcome measures were differences between multiple observations of serum ferritin concentrations. Secondary outcomes were survival analysis, adverse events, and costs. Consecutive thalassaemia patients (275) were assessed for eligibility; 213 of these were randomized and underwent intention-to-treat analysis. The decrease of serum ferritin levels during the treatment period was statistically significant higher in sequential DFP-DFO patients compared with DFP-alone patients (P = 0.005). Kaplan-Meier survival analysis for the two chelation treatments did not show any statistically significant differences (long-rank test, P = 0.3145). Adverse events and costs were comparable between the groups. The trial results show that sequential DFP-DFO treatment compared with DFP alone significantly decreased serum ferritin concentration during treatment for 5 years without significant differences regarding survival, adverse events, or costs.
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PMID:Long-term sequential deferiprone-deferoxamine versus deferiprone alone for thalassaemia major patients: a randomized clinical trial. 1923 76

Deferoxamine (DFO) was granted orphan drug status for the treatment of traumatic spinal cord injury but its neuroprotective mechanism is not well understood. We therefore investigated the mode of action of DFO in serum-starved and/or iron-stressed cultures of rat dorsal root ganglion (DRG) cells. We probed for redox signaling by determining hemeoxygenase-1 activity and by measuring expression of intracellular iron metabolism-related proteins under pro-oxidative conditions. We also employed DNA microarrays to better understand the genomic response of DRG cultures to treatment with DFO thereby enabling the generation of hypotheses. Essentially, DFO treatment resulted in outgrowth of neurofilament 200-positive neurites and induction of synapse formation as determined by immunoblotting, transmission electron microscopy and immunofluorescence confocal microscopy. Furthermore, DFO treatment of DRG cell cultures activated neuroprotective and antioxidative programs such as matrix metallopeptidase 2 and apolipoprotein D to promote neurite regeneration. Indeed, DFO reduced markedly reactive oxygen species formation, increased the expression of hemeoxygenase-1 and improved iron management through regulation of transferrin receptor and ferritin. We propose DFO treatment of DRG cell cultures to completely abolish the oxidative effect of ferrous iron (Fe(2+)). Taken collectively, DFO reduced oxidative stress and induced synthesis of neuroprotective and antioxidative molecules to foster nerve repair and functional recovery. Our findings help to better understand the therapeutic benefit of DFO in the treatment of spinal cord injury.
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PMID:Deferoxamine-induced neurite outgrowth and synapse formation in postnatal rat dorsal root ganglion (DRG) cell cultures. 1958 Oct 22


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