Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0016719 (Friedreich's ataxia)
 2,098 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In recent years there has been much interest in the development of iron (Fe) chelators for treatment of a number of clinical conditions in addition to beta-thalassaemia. These include cancer, anthracycline-mediated cardiotoxicity, malaria, AIDS and the severe neurodegenerative disease, Friedreich's ataxia. In this review I will discuss the most recent advances achieved in the potential treatment of these conditions using Fe chelators.
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PMID:The therapeutic potential of iron chelators. 1113 44

Our laboratories have prepared a novel class of iron (Fe) chelators of the 2-pyridylcarboxaldehyde isonicotinoyl hydrazone (PCIH) class. This article will review the iron chelation efficacy of this series of chelators, both in cell culture and in animal models. Several PCIH analogs were shown to be effective at inducing iron mobilization and preventing iron uptake from the iron-transport protein, transferrin. Moreover, several of these ligands were effective at permeating the mitochondrion and inducing iron release. Studies in mice demonstrated that the PCIH analog, PCTH, was orally active and well tolerated by mice at doses ranging from 50 to 100 mg kg(-1), twice daily (b.d.). A dose-dependent increase in fecal 59Fe excretion was observed in the PCTH-treated group. This level of iron excretion was similar to that found for the orally effective chelators, pyridoxal isonicotinoyl hydrazone (PIH) and deferiprone (L1). The PCIH group of ligands clearly has the potential for the treatment of beta-thalassemia (thal) and Friedreich's Ataxia (FA).
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PMID:PCTH: a novel orally active chelator for the treatment of iron overload disease. 1654 Apr 21

Iron imbalance/accumulation has been implicated in oxidative injury associated with many degenerative diseases such as hereditary hemochromatosis, beta-thalassemia, and Friedreich's ataxia. Mitochondria are particularly sensitive to iron-induced oxidative stress - high loads of iron cause extensive lipid peroxidation and membrane permeabilization in isolated mitochondria. Here we detected and characterized mitochondrial DNA damage in isolated rat liver mitochondria exposed to a Fe2+-citrate complex, a small molecular weight complex. Intense DNA fragmentation was induced after the incubation of mitochondria with the iron complex. The detection of 3' phosphoglycolate ends at the mtDNA strand breaks by a 32P-postlabeling assay, suggested the involvement of hydroxyl radical in the DNA fragmentation induced by Fe2+-citrate. Increased levels of 8-oxo-7,8-dihydro-2'-deoxyguanosine also suggested that Fe2+-citrate-induced oxidative stress causes mitochondrial DNA damage. In conclusion, our results show that iron-mediated lipid peroxidation was associated with intense mtDNA damage derived from the direct attack of reactive oxygen species.
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PMID:Mitochondrial DNA damage associated with lipid peroxidation of the mitochondrial membrane induced by Fe2+-citrate. 1693 39

A standard aqueous stem bark extract from selected species of Mangifera indica L. (Anacardiaceae)--Vimang, whose major polyphenolic component is mangiferin, displays potent in vitro and in vivo antioxidant activity. The present study provides evidence that the Vimang-Fe(III) mixture is more effective at scavenging 2,2-diphenyl-1-picrylhydrazyl (DPPH) and superoxide radicals, as well as in protecting against t-butyl hydroperoxide-induced mitochondrial lipid peroxidation and hypoxia/reoxygenation-induced hepatocytes injury, compared to Vimang alone. Voltammetric assays demonstrated that Vimang, in line with the high mangiferin content of the extract, behaves electrochemically like mangiferin, as well as interacts with Fe(III) in close similarity with mangiferin's interaction with the cation. These results justify the high efficiency of Vimang as an agent protecting from iron-induced oxidative damage. We propose Vimang as a potential therapy against the deleterious action of reactive oxygen species generated during iron-overload, such as that occurring in diseases like beta-thalassemia, Friedreich's ataxia and haemochromatosis.
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PMID:Interaction of Vimang (Mangifera indica L. extract) with Fe(III) improves its antioxidant and cytoprotecting activity. 1700 Jan 17

Various pathologies are characterized by the accumulation of toxic iron in cell compartments. In anemia of chronic disease, iron is withheld by macrophages, leaving extracellular fluids iron-depleted. In Friedreich ataxia, iron levels rise in the mitochondria of excitable cells but decrease in the cytosol. We explored the possibility of using deferiprone, a membrane-permeant iron chelator in clinical use, to capture labile iron accumulated in specific organelles of cardiomyocytes and macrophages and convey it to other locations for physiologic reuse. Deferiprone's capacity for shuttling iron between cellular organelles was assessed with organelle-targeted fluorescent iron sensors in conjunction with time-lapse fluorescence microscopy imaging. Deferiprone facilitated transfer of iron from extracellular media into nuclei and mitochondria, from nuclei to mitochondria, from endosomes to nuclei, and from intracellular compartments to extracellular apotransferrin. Furthermore, it mobilized iron from iron-loaded cells and donated it to preerythroid cells for hemoglobin synthesis, both in the presence and in the absence of transferrin. These unique properties of deferiprone underlie mechanistically its capacity to alleviate iron accumulation in dentate nuclei of Friedreich ataxia patients and to donate tissue-chelated iron to plasma transferrin in thalassemia intermedia patients. Deferiprone's shuttling properties could be exploited clinically for treating diseases involving regional iron accumulation.
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PMID:Redistribution of accumulated cell iron: a modality of chelation with therapeutic implications. 1797 16

Free radical formation is primarily initiated from metal catalytic centers involving iron and copper. Under certain conditions, free radical reactions can lead to free radical cascades and oxidative stress, which can cause biomolecular, cellular and tissue damage (FRD). The use of natural antioxidants to prevent FRD is in most cases not effective. Many chelators have been shown to inhibit free radical reactions and toxicity in experimental models of both in vitro and in vivo. Deferiprone (L1) has been shown to be effective and safe in the reversal of accelerating oxidative stress related tissue damage in iron loading and non iron loading conditions such as cardiomyopathy in thalassaemia, acute kidney disease and Friedreich ataxia. The selection of chelating drugs and their combinations could be used as new strategies for antioxidant therapies. In vitro, in vivo and clinical data suggest that L1 is the most potent drug antioxidant because of its high therapeutic index, ability to reach extracellular and intracellular compartments of many tissues and ability to inhibit both iron and copper catalysed free radical reactions.
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PMID:Prospects for introducing deferiprone as potent pharmaceutical antioxidant. 1948 34

Tissue damage caused by oxidative stress is a common characteristic of many conditions involving different major organs such as the brain, heart, liver and kidneys. The treatment of such conditions using classical antioxidants is not in most cases sufficient or effective because it lacks specificity and has a low therapeutic index. Increased evidence from in vitro, in vivo and clinical studies suggest that deferiprone (L1) can be used as a potent pharmaceutical antioxidant by mobilizing labile iron and copper and/or inhibiting their catalytic activity in the formation of free radicals and oxidative stress in tissue damage. The high therapeutic index, tissue penetration, rapid iron binding and clearance of the iron complex, and the low toxicity of L1, support its application as an antioxidant pharmaceutical for adjuvant, alternative or main therapy, especially in conditions where other treatments have failed. Substantial clinical improvement and reversal in most cases of the tissue damage has been observed in cardiomyopathy in thalassemia, diabetic nephropathy and glomerulonephritis in kidney disease, Friedreich's Ataxia and Fanconi Anemia patients. In contrast to L1, both deferoxamine (DFO) and deferasirox (DFRA) have major disadvantages in their use in non iron loading conditions due to toxicity implications. Further studies in the above and other conditions and optimization of the L1 therapy in each individual will increase the prospects of the application and role of L1 as a universal antioxidant pharmaceutical.
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PMID:Risk/benefit assessment, advantages over other drugs and targeting methods in the use of deferiprone as a pharmaceutical antioxidant in iron loading and non iron loading conditions. 1981 84

Millions of people worldwide suffer from iron overload toxicity diseases such as transfusional iron overload in thalassaemia and hereditary haemochromatosis. The accumulation and presence of toxic focal iron deposits causing tissue damage can also be identified in Friedreich's ataxia, Alzheimer's, Parkinson's, renal and other diseases. Different diagnostic criteria of toxicity and therapeutic interventions apply to each disease of excess or misplaced iron. Magnetic resonance imaging relaxation times T2 and T2* for monitoring iron deposits in organs and iron biomarkers such as serum ferritin and transferrin iron saturation have contributed in the elucidation of iron toxicity mechanisms and pathways, and also the evaluation of the efficacy and mode of action of chelating drugs in the treatment of diseases related to iron overload, toxicity and metabolism. Similarly, histopathological and electron microscopy diagnostic methods have revealed mechanisms of iron overload toxicity at cellular and sub-cellular levels. These new diagnostic criteria and chelator dose adjustments could apply in different or special patient categories e.g. thalassaemia patients with normal iron stores, where iron deficiency and over-chelation toxicity should be avoided.
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PMID:New targeted therapies and diagnostic methods for iron overload diseases. 2893 May 16

Highly active cardiomyocytes need iron for their metabolic activity. In physiological conditions, iron turnover is a delicate process which is dependent on global iron supply and local autonomous regulatory mechanisms. Though less is known about the autonomous regulatory mechanisms, data suggest that these mechanisms can preserve cellular iron turnover even in the presence of systemic iron disturbance. Therefore, activity of local iron protein machinery and its relationship with global iron metabolism is important to understand cardiac iron metabolism in physiological conditions and in cardiac disease. Our knowledge in this respect has helped in designing therapeutic strategies for different cardiac diseases. This review is a synthesis of our current knowledge concerning the regulation of cardiac iron metabolism. In addition, different models of cardiac iron dysmetabolism will be discussed through the examples of heart failure (cardiomyocyte iron deficiency), myocardial infarction (acute changes in cardiac iron turnover), doxorubicin-induced cardiotoxicity (cardiomyocyte iron overload in mitochondria), thalassaemia (cardiomyocyte cytosolic and mitochondrial iron overload) and Friedreich ataxia (asymmetric cytosolic/mitochondrial cardiac iron dysmetabolism). Finally, future perspectives will be discussed in order to resolve actual gaps in knowledge, which should be helpful in finding new treatment possibilities in different cardiac diseases.
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PMID:Keeping heart homeostasis in check through the balance of iron metabolism. 3116 83

Deferiprone (L1) was originally designed, synthesised and screened in vitro and in vivo in 1981 by Kontoghiorghes G. J. following his discovery of the novel alpha-ketohydroxypyridine class of iron chelators (1978-1981), which were intended for clinical use. The journey through the years for the treatment of thalassaemia with L1 has been a very difficult one with an intriguing turn of events, which continue until today. Despite many complications, such as the extensive use of L1 suboptimal dose protocols, the aim of chelation therapy-namely, the complete removal of excess iron in thalassaemia major patients, has been achieved in most cases following the introduction of specific L1 and L1/deferoxamine combinations. Many such patients continue to maintain normal iron stores. Thalassemia has changed from a fatal to chronic disease; also thanks to L1 therapy and thalassaemia patients are active professional members in all sectors of society, have their own families with children and grandchildren and their lifespan is approaching that of normal individuals. No changes in the low toxicity profile of L1 have been observed in more than 30 years of clinical use and prophylaxis against the low incidence of agranulocytosis is maintained using mandatory monitoring of weekly white blood cells' count. Thousands of thalassaemia patients are still denied the cardioprotective and other beneficial effects of L1 therapy. The safety of L1 in thalassaemia and other non-iron loaded diseases resulted in its selection as one of the leading therapeutics for the treatment of Friedreich's ataxia, pantothenate kinase-associated neurodegeneration and other similar cases. There are also increasing prospects for the application of L1 as a main, alternative or adjuvant therapy in many pathological conditions including cancer, infectious diseases and as a general antioxidant for diseases related to free radical pathology.
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PMID:The History of Deferiprone (L1) and the Paradigm of the Complete Treatment of Iron Overload in Thalassaemia. 3193 21


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