Publications by authors named "Josef Lichtmannegger"

Article Synopsis
  • Excess copper is harmful in Wilson's disease (WD), and current treatments require continuous dosage, leading to adherence issues and adverse reactions.
  • This study tested a new copper-binding agent, ARBM101, in WD rats, showing it effectively reduces liver copper to normal levels within 8 days, surpassing traditional treatments.
  • The new treatment strategy involves short, repeated cycles of ARBM101 followed by long breaks, promoting healthier long-term survival for WD rats.
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In Wilson disease, excessive copper accumulates in patients' livers and may, upon serum leakage, severely affect the brain according to current viewpoints. Present remedies aim at avoiding copper toxicity by chelation, for example, by D-penicillamine (DPA) or bis-choline tetrathiomolybdate (ALXN1840), the latter with a very high copper affinity. Hence, ALXN1840 may potentially avoid neurological deterioration that frequently occurs upon DPA treatment.

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Aerobic methanotrophy is strongly controlled by copper, and methanotrophs are known to use different mechanisms for copper uptake. Some methanotrophs secrete a modified polypeptide-methanobactin-while others utilize a surface-bound protein (MopE) and a secreted form of it (MopE*) for copper collection. As different methanotrophs have different means of sequestering copper, competition for copper significantly impacts methanotrophic activity.

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Background & Aims: In Wilson disease, ATP7B mutations impair copper excretion into bile. Hepatic copper accumulation may induce mild to moderate chronic liver damage or even acute liver failure. Etiologic factors for this heterogeneous phenotype remain enigmatic.

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Background & Aims: Wilson disease (WD) is an inherited disorder of copper metabolism that leads to copper accumulation and toxicity in the liver and brain. It is caused by mutations in the adenosine triphosphatase copper transporting β gene (ATP7B), which encodes a protein that transports copper from hepatocytes into the bile. We studied ATP7B-deficient cells and animals to identify strategies to decrease copper toxicity in patients with WD.

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Wilson disease (WD) is a rare genetic disorder of the copper metabolism leading to systemic copper accumulation, predominantly in the liver. The therapeutic approach in WD patients is the generation of a negative copper balance and the maintenance of copper homeostasis, currently by the use of copper chelators such as D-penicillamine (D-PA). However, in circumstances of delayed diagnosis, poor treatment compliance, or treatment failure, mortality is almost certain without hepatic transplantation.

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Wilson disease (WD) is characterized by a disrupted copper homeostasis resulting in dramatically increased copper levels, mainly in liver and brain. While copper damage to mitochondria is an established feature in WD livers, much less is known about such detrimental copper effects in other organs. We therefore assessed the mitochondrial sensitivity to copper in a tissue specific manner, namely of isolated rat liver, kidney, heart, and brain mitochondria.

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In Wilson disease (WD), functional loss of ATPase copper-transporting β (ATP7B) impairs biliary copper excretion, leading to excessive copper accumulation in the liver and fulminant hepatitis. Current US Food and Drug Administration- and European Medicines Agency-approved pharmacological treatments usually fail to restore copper homeostasis in patients with WD who have progressed to acute liver failure, leaving liver transplantation as the only viable treatment option. Here, we investigated the therapeutic utility of methanobactin (MB), a peptide produced by Methylosinus trichosporium OB3b, which has an exceptionally high affinity for copper.

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Mitochondria are key organelles for cellular energy production and cell death decisions. Consequently, a plethora of conditions which are toxic to cells are known to directly attack these organelles. However, mitochondria originating from different tissues differ in their sensitivity to toxic insults.

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In Wilson's disease (WD) and related animal models, liver mitochondria are confronted with an increasing copper burden. Physiologically, the mitochondrial matrix may act as a dynamic copper buffer that efficiently distributes the metal to its copper-dependent enzymes. Mitochondria are the first responders in the event of an imbalanced copper homeostasis, as typical changes of their structure are among the earliest observable pathological features in WD.

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The gaseous olefin ethylene (ET) is metabolized in mammals to the carcinogenic epoxide ethylene oxide (EO). Although ET is the largest volume organic chemical worldwide, the EO burden in ET-exposed humans is still uncertain, and only limited data are available on the EO burden in ET-exposed rodents. Therefore, EO was quantified in blood of mice, rats, or 4 volunteers that were exposed once to constant atmospheric ET concentrations of between 1 and 10 000 ppm (rodents) or 5 and 50 ppm (humans).

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Mitochondrial dysfunctions decisively contribute to the progression of human diseases, implying that functional tests of isolated mitochondria may furnish conclusive information for diagnosis and therapy. Classical mitochondrial isolation methods, however, lack precisely adjustable settings for cell rupture, which is the most critical step in this procedure, and this complicates subsequent analyses. Here, we present an efficient method to isolate functionally active, intact mitochondria from cultured or primary cells and minute tissue samples in a rapid, highly reproducible manner.

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The cell-toxic bile salt glycochenodeoxycholic acid (GCDCA) and taurochenodeoxycholic acid (TCDCA) are responsible for hepatocyte demise in cholestatic liver diseases, while tauroursodeoxycholic acid (TUDCA) is regarded hepatoprotective. We demonstrate the direct mitochondrio-toxicity of bile salts which deplete the mitochondrial membrane potential and induce the mitochondrial permeability transition (MPT). The bile salt mediated mechanistic mode of destruction significantly differs from that of calcium, the prototype MPT inducer.

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Previous quantitative proteomic studies on the actions of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in 5L rat hepatoma cells, a cell model frequently used for investigating the mechanisms of TCDD toxicity, had indicated that dioxin exposure reduced the abundance of numerous proteins which are regulated at the level of protein synthesis initiation. In the present study, we have analysed the mechanism mediating this inhibition. TCDD treatment of the cells largely prevented the activation of eukaryotic translation initiation factor 4E-binding protein 1, a regulator of translation initiation and substrate of the mammalian target of rapamycin (mTOR).

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Article Synopsis
  • * The study examines liver mitochondria in rats lacking the Atp7b gene, finding that copper accumulation leads to structural changes in mitochondria, such as enlarged cristae and widened intermembrane spaces, before causing functional impairments.
  • * Copper exposure also resulted in specific modifications of mitochondrial proteins in a controlled environment, and treatment with copper-chelating agents helped restore mitochondrial integrity, indicating mitochondria play a critical role in the effects of copper in WD.
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Copper is an essential redox-active metal ion which in excess becomes toxic due to the formation of reactive oxygen species. In Wilson disease the elevated copper level in liver leads to chronic oxidative stress and subsequent hepatitis. This study was designed to evaluate the copper chelating efficiency of the bacterial methanobactin (MB) in a rat model for Wilson disease.

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Wilson's disease is a human genetic disorder which results in copper accumulation in liver and brain. Treatments such as copper chelation therapy or dietary supplementation with zinc can ameliorate the effects of the disease, but if left untreated, it results in hepatitis, neurological complications, and death. Tetrathiomolybdate (TTM) is a promising new treatment for Wilson's disease which has been demonstrated both in an animal model and in clinical trials.

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Article Synopsis
  • A significant increase in mitochondrial membrane permeability can lead to the irreversible rupture of the mitochondrial outer membrane, resulting in cell death due to the release of harmful molecules and metabolic disruption.
  • Current methods for assessing outer membrane damage are mostly indirect and not representative of all mitochondria, necessitating a more accurate approach.
  • This study introduces free flow electrophoresis as a technique to effectively separate and analyze rat liver mitochondria based on their outer membrane integrity and cytochrome c content, helping understand the effects of permeability transition and ischemia/reperfusion damage.
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This protocol describes the purification of mitochondria from rat liver with the aid of zone electrophoresis in a free flow device (ZE-FFE). Starting from liver homogenate, cell debris and nuclei are removed by low speed centrifugation. A crude mitochondrial fraction is obtained by medium speed centrifugation and is further purified by washing followed by a Nycodenz gradient centrifugation.

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As part of a comprehensive survey of the impact of the environmental pollutant and hepatocarcinogen 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on the proteome of hepatic cells, we have performed a high resolution two-dimensional gel electrophoresis study on the rat hepatoma cell line 5L. 78 protein species corresponding to 73 different proteins were identified as up- or down-regulated following exposure of the cells to 1 nm TCDD for 8 h. There was an overlap of only nine proteins with those detected as altered by TCDD in our recent study using the non-gel-based isotope-coded protein label method (Sarioglu, H.

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Background/aims: Tetrathiomolybdate (TTM) is a potent copper-chelating agent that has been shown to be effective in Wilson disease patients with neurological symptoms. Here, we investigate the potential use of TTM in treating the acute hepatic copper toxicosis in Long-Evans Cinnamon (LEC) rats, an authentic model for Wilson disease.

Methods: After the onset of acute hepatitis, LEC rats were treated once with 10 mg TTM/kg.

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The Long-Evans cinnamon (LEC) rat, an authentic model for Wilson disease, is characterized by a mutation in the Atp7b gene leading to a defective copper excretion and, as a consequence, to an accumulation of the metal in the liver and copper-associated hepatotoxicity. In the present communication expression profiles of genes in the liver from wild-type Long-Evans agouti (LEA) and LEC rats at different stages of copper accumulation and liver disease were investigated. Disease states were defined according to serum aspartate aminotransferase activity and bilirubin levels in serum and from histopathology of the liver.

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Wilson's disease is an autosomal recessive human illness in which large quantities of copper accumulate in various organs, including the brain and the liver. If left untreated, it results in hepatitis, neurological complications, and death. Long-Evans Cinnamon (LEC) rats have a homologous mutation to Wilson's disease and thus provide an animal model.

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