metallothionein and Hepatolenticular-Degeneration

Wilson's disease is an autosomal recessive disease caused by mutations on the ATP7B gene found on chromosome 13. Since the corresponding ATPase is in charge of copper (Cu) distribution and excretion in the liver, its malfunctioning leads to Cu overload. This short review deals with treatments of this rare disease, which aim at decreasing Cu toxicity and are, therefore, based on chelation therapy. The drugs used since the 1950s are described first, then a novel approach developed in our laboratory is presented. Since the liver is the main organ of Cu distribution in the body, we targeted the pool of intracellular Cu in hepatocytes. This Cu pool is in the +1 oxidation state, and therefore soft sulfur ligands inspired from binding sites found in metallothioneins were developed. Their targeting to the hepatocytes by functionalization with ligands of the asialoglycoprotein receptor led to their cellular incorporation and intracellular Cu chelation.

Topics: Asialoglycoprotein Receptor; Chelating Agents; Copper; Drug Delivery Systems; Drug Design; Glycoconjugates; Hepatocytes; Hepatolenticular Degeneration; Humans; Ligands; Metallothionein; Oxidation-Reduction

Metals can directly or indirectly cause an increase in reactive oxygen species (ROS) accumulation in cells, and this may result in programmed cell death. A number of previous studies have shown that zinc (Zn) modulates mitogenic activity via several signalling pathways, such as AKT, mitogen-activated protein kinase (MAPK), nuclear factor-kappa B (NF -κB), AP-1 and p53. The exact role that Zn plays in the regulation of apoptosis remains ambiguous. Intracellular free Zn modulates p53 activity and stability, and excess Zn alters the p53 protein structure and down-regulates p53's binding to DNA. Copper (Cu) accumulation causes apoptosis that seems to be mediated by DNA damage and subsequent p53 activation. Cu can also displace Zn from its normal binding site on p53, resulting in abnormal protein folding and disruption of p53 function. In spite of the induction of the tumour suppressor p53, hepatic Cu accumulation significantly increases the risk of cancerous neoplasm both in humans and rats, suggesting that p53 function may be impaired in these cells. It is generally understood that imbalances in Cu and Zn levels may lead to a higher prevalence of p53 mutations. An increased number of p53 mutations have been found in liver samples from Wilson's disease (WD) patients. High levels of the p53 mutation most probably contribute to the pathogenesis of cancer in individuals with WD, but the cause and effect are not clear. The protein p53 also plays a crucial role in the transcriptional regulation of metallothionein, which indicates a novel regulatory role for p53. This review discusses the central role of p53 and the redox-inert metal Zn in the cellular stress responses induced by the redox active biometal Cu.

Topics: Animals; Copper; Genes, p53; Hepatolenticular Degeneration; Humans; Metallothionein; Oxidative Stress; Radiotherapy; Tumor Suppressor Protein p53; Zinc

The transition metal copper (Cu) is an essential trace element for all biota. Its redox properties bestow Cu with capabilities that are simultaneously essential and potentially damaging to the cell. Free Cu is virtually absent in the cell. The descriptions of the structural and functional organization of the metallothioneins, Cu-chaperones and P-type ATPases as well as of the mechanisms that regulate their distribution and functioning in the cell have enormously advanced our understanding of the Cu homeostasis and metabolism in the last decade. Cu is stored by metallothioneins and distributed by specialized chaperones to specific cell targets that make use of its redox properties. Transfer of Cu to newly synthesized cuproenzymes and Cu disposal is performed by the individual or concerted actions of the P-type ATPases ATP7A and ATP7B expressed in tissues. In mammalians liver is the major captor, distributor and excreter of Cu. Mutations in the P-type ATPases that interfere with their functioning and traffic are cause of the life-threatening Wilson (ATP7B) and Menkes (ATP7A) diseases.

Topics: Adenosine Triphosphatases; Animals; Cation Transport Proteins; Copper; Copper-Transporting ATPases; Diet; Electron Transport Complex IV; Glutathione; Hepatolenticular Degeneration; Homeostasis; Humans; Liver; Menkes Kinky Hair Syndrome; Metallothionein; Models, Biological; Molecular Chaperones; Mutation; Oxidation-Reduction; Superoxide Dismutase; Superoxide Dismutase-1

Metallothioneins (MTs) are ubiquitous metal-binding proteins that have been highly conserved throughout evolution. Although their physiological function is not completely understood, they are involved in diverse processes including metal homeostasis and detoxification, the oxidative stress response, inflammation, and cell proliferation. Te human MT gene family consists of at least 18 isoforms, containing pseudogenes as well as genes encoding functional proteins. Most of the MT isoforms can be induced by a wide variety of substances, such as metals, cytokines, and hormones. Different cell types express discrete MT isoforms, which reflects the specifically adapted functions of MTs and a divergence in their regulation. Te aberrant expression of MTs has been described in a number of diseases, including Crohn's disease, cancer, Alzheimer's disease, amyotrophic lateral sclerosis, Menkes disease, and Wilson's disease. Therefore, a thorough understanding of MT gene regulation is imperative. To date, the transcriptional regulation of MTs has primarily been studied in mice. While only four murine MT isoforms exist, the homology between murine and human MTs allows for the evaluation of the regulatory regions in their respective promoters. Here, we review the aberrant expression of MTs in human diseases and the mechanisms that regulate MT1 expression based on an in silico evaluation of transcription factor binding sites.

Topics: Alzheimer Disease; Animals; Crohn Disease; Gene Expression Regulation; Hepatolenticular Degeneration; Humans; Menkes Kinky Hair Syndrome; Metallothionein; Mice; Neoplasms; Phylogeny; Promoter Regions, Genetic

The transition metal copper is an essential trace element involved in many enzymatic processes that require redox-chemistry. The redox-activity of copper is potentially harmful. Severe imbalance of copper homeostasis can occur with some hereditary disorders of copper metabolism. Copper is acquired from the diet by intestinal absorption and is subsequently distributed throughout the body. The regulation of intestinal copper absorption to maintain whole-body copper homeostasis is currently poorly understood. This review evaluates novel findings regarding the molecular mechanism of intestinal copper uptake. The role of recently identified transporters in enterocyte copper uptake and excretion into the portal circulation is described, and the regulation of dietary copper uptake during physiological and pathophysiological conditions is discussed.

Topics: Biological Transport; Ceruloplasmin; Copper; Enterocytes; Hepatolenticular Degeneration; Homeostasis; Humans; Intestinal Absorption; Menkes Kinky Hair Syndrome; Metallothionein; Oxidation-Reduction; Trace Elements

Copper (Cu) is an essential trace element and constitutes the active center of the redox Cu enzymes such as Cu, Zn-superoxide dismutase (Cu, Zn-SOD), ceruloplasmin and cytochrome c oxidase. Among hereditary diseases due to a defect in the metabolism of Cu, Menkes disease (caused by a Cu deficiency) and Wilson disease (caused by the excessive accumulation of Cu) have been shown to be caused by the mutation of genes encoding Cu-binding ATPase for the efflux of Cu, ATP7A and ATP7B, respectively. Following the identification of these causative genes, intracellular Cu transporters (Cu chaperones) specific for the Golgi apparatus, mitochondria and Cu, Zn-SOD were discovered, and these findings have facilitated the study of the underlying mechanisms of the biological regulation of Cu. Apart from these physiological and biochemical studies, toxicological studies have elucidated the underlying mechanisms of the occurrence of acute hepatitis caused by the accumulation of Cu accumulating in the liver of an animal model for Wilson disease, LEC rats. In these toxicological studies, two biological aspects of metallothionein (MT), i.e., antioxidant and prooxidant depending on the Cu/Zn ratio in Cu-containing MT have been proposed. The present article overviews the recent findings on the biological regulation of Cu and on the toxicological aspect of Cu. It is known that Cu forms a stable ternary complex with molybdenum and sulfur under reductive conditions in the body. On the basis of this observation, tetrathiomolybdate (TTM) has been applied to remove Cu from the liver of Long-Evans rats with a cinnamon-like coat color (LEC) rats. Precise mechanisms underlying the complex formation between Cu bound to MT and TTM were presented, and an appropriate protocol for the chelation therapy was also proposed together with the mechanisms underlying the occurrence of side-effects.

Topics: Adenosine Triphosphatases; Animals; Carrier Proteins; Cation Transport Proteins; Chelating Agents; Copper; Copper-Transporting ATPases; Disease Models, Animal; Hepatolenticular Degeneration; Humans; Liver; Metallothionein; Molybdenum; Rats; Rats, Inbred LEC; Recombinant Fusion Proteins

Toxic milk mutant (tx) mice accumulate excess copper (Cu) in liver with age and develop symptoms similar to those seen in human Wilson disease. Because metallothionein (MT) is the major Cu-binding protein in tx mouse liver and Cu-MT can enhance lipid peroxidation initiated by an organic hydroperoxide, the potential genotoxicity of Cu-MT in tx mice was assessed in male tx mice (11 to 12 months old) and in age- and sex-matched control wild-type (DL) mice. Toxic milk mutant mice, but not control DL mice, developed regenerative liver nodules (tx-N) with normal histologic appearance. Residual, non-nodular tx mouse liver (tx-R) was microscopically abnormal with large, atypical hepatocytes. The levels of Cu, zinc (Zn), and MT, and the numbers of apoptotic cells (APC) in tx-N, tx-R, and DL livers were measured by atomic absorption spectrophotometry, 109cadmium-heme assay, and the TUNEL method, respectively. Significantly higher levels of MT, Cu, and Zn, as well as increased numbers of APC were found in both tx-N and tx-R compared with DL mouse livers. Intense nuclear and cytoplasmic immunohistochemical staining for MT was observed in both normal and atypical hepatocytes of the tx mouse, whereas only cytoplasmic staining for MT was detected in DL mouse liver tissue. Accumulated Cu could be detected in tx-R and tx-N liver by rhodanine staining but was not detected in other tx mouse organs, or in mouse liver or other organs of DL. The number of APC and level of MT were significantly higher in tx-R liver compared with both tx-N and DL liver. These results suggest that: (a) aged tx mouse accumulate excess Cu in liver accompanied by striking morphologic changes, and (b) although MT binds to Cu in tx mouse liver, the presence of high Cu-MT and Cu in the nucleus can be genotoxic and may lead to enhanced apoptosis.

Topics: Animals; Apoptosis; Copper; Hepatolenticular Degeneration; Immunohistochemistry; Kidney; Liver; Male; Metallothionein; Mice; Mice, Mutant Strains; Reference Values; Spleen; Tissue Distribution; Zinc

Wilson's disease is an inherited disorder of copper accumulation. The basic defect is a failure of excretion of excess copper in the bile by the liver for loss in the stool. The accumulating copper causes damage primarily to the liver and the brain. Patients typically present in the second to the fourth decades of life with liver disease, a neurological disease of the movement disorder type, or a wide array of behavioural disturbances. Because the manifestations of Wilson's disease are so protean, and the disease masquerades so well as something else, recognition of the possibility of Wilson's disease is a major problem, leading to serious underdiagnosis of the disease. Excellent therapies exist for both the prophylaxis and treatment of Wilson's disease. The longer recognition and diagnosis are delayed, the greater the risk of permanent damage to liver and/or brain. The availability of effective therapy and the risks in delay or therapy make the earliest possible diagnosis critical. Once the disease comes under consideration, a series of diagnostic steps can be undertaken which almost always establish or rule out the diagnosis of Wilson's disease. These include urine copper, blood ceruloplasmin, slit lamp examination for Kayser-Fleischer rings, and liver biopsy with quantitative copper assay. Currently, there are 4 drugs being used as anticopper agents in Wilson's disease. These are zinc, which blocks intestinal absorption of copper, penicillamine and trientine, both of which are chelators that increase urinary excretion of copper, and tetrathiomolybdate which forms a tripartite complex with copper and protein, and can block copper absorption from the intestine, or render blood copper non-toxic. Zinc is clearly the treatment of choice, in our opinion, for maintenance therapy, for the treatment of the presymptomatic patient from the beginning and for the treatment of the pregnant patient, because of its complete efficacy and lack of toxicity. For the initial treatment of the patient presenting with mild liver failure, we empirically use a combination of trientine and zinc. Trientine gives a strong, fast, negative copper balance, and zinc induces hepatic metallothionein, which sequesters hepatic copper. For the initial treatment of patients presenting with neurological disease we use an experimental drug, tetrathiomolybdate, which provides rapid, safe control of copper. These latter patients are at great risk of serious permanent neurological worsening with

Topics: Chelating Agents; Copper; Female; Hepatolenticular Degeneration; Humans; Liver; Metallothionein; Molybdenum; Penicillamine; Pregnancy; Trientine; Zinc

Disordered copper (Cu) metabolism in LEC rats, an animal model of Wilson disease, was characterized by specifying Cu in the liver, bloodstream and kidneys during the accumulation process and at the onset of jaundice; Cu accumulates in the liver with age in a form bound to metallothionein (MT). Massive Cu is liberated from MT when Cu accumulates beyond the capacity of MT synthesis. Cu bound to MT is not supplied to ceruloplasmin (Cp) during its maturation process, while the metal is transferred to Cu,zinc (Zn)-superoxide dismutase (SOD) directly from MT. Cu ions not bound to MT are transferred to Cp and the holo-Cp is excreted into the bloodstream near and at the onset of jaundice. Cu accumulated in the liver in a form bound to MT is removed selectively by tetrathiomolybdate (TTM), and the animal at the beginning of the onset of jaundice recovers by the chelation therapy. Mechanisms of the removal reaction were proposed to involve formation of MT/TTM, Cu/TTM, and/or polymeric Cu/TTM complexes according to the stoichiometry of TTM to Cu. The Cu/TTM complex was assumed to be effluxed into the bloodstream and to bind specifically to albumin. TTM is taken up by the liver in accordance with the Cu content. The toxicity of Cu was explained by the active oxygen species produced in Cu-mediated reactions, and the participation of MT.

Topics: Animals; Copper; Disease Models, Animal; Hepatolenticular Degeneration; Metallothionein; Rats; Rats, Mutant Strains

Topics: Acrodermatitis; Cadmium; Chromium; Copper; Disease; Disease Models, Animal; Growth; Hemochromatosis; Hepatolenticular Degeneration; Humans; Iron; Magnesium; Male; Menkes Kinky Hair Syndrome; Metallothionein; Milk, Human; Nucleic Acids; Selenium; Testis; Trace Elements; Zinc

Various inherited disorders of copper metabolism in man and animals are reviewed. Emphasis is placed on the use of cultured cells from mutants to determine the primary molecular defects and to acquire basic knowledge of normal copper metabolism. This allows better diagnostic tests and possible treatment of the disorders. Menkes' disease in humans and mottled mouse mutants are discussed in detail, as they illustrate these approaches.

Topics: Animals; Brain Diseases, Metabolic; Cells, Cultured; Copper; Disease Models, Animal; Dogs; Electron Transport Complex IV; Female; Fibroblasts; Hepatolenticular Degeneration; Humans; Menkes Kinky Hair Syndrome; Metalloproteins; Metallothionein; Mice; Mice, Mutant Strains; Mice, Quaking; Pregnancy; Protein-Lysine 6-Oxidase

Topics: Absorption; Acrodermatitis; Animals; Biological Availability; Biological Transport, Active; Blood Proteins; Copper; Enzymes; Hepatolenticular Degeneration; Humans; Ligands; Menkes Kinky Hair Syndrome; Metallothionein; Zinc

Topics: Ceruloplasmin; Copper; Cornea; Cytosol; Hepatolenticular Degeneration; Humans; Liver; Liver Cirrhosis; Lysosomes; Metallothionein; Mitochondria, Liver; Penicillamine; Prognosis; Protein Binding; Radioisotopes

Topics: Animals; Biological Transport; Ceruloplasmin; Copper; Golgi Apparatus; Hepatolenticular Degeneration; Humans; Liver; Lysosomes; Metalloproteins; Metallothionein; Mitochondria, Liver; Models, Biological; Rats

Wilson disease (WD) is a genetic disorder of copper metabolism caused by mutations in the ATP7B gene. Toxic copper accumulation leads to hepatic, neurologic, and psychiatric disorders with variable presentation. Metallothionein (MT) immunohistochemistry was proposed as a diagnostic marker.. MT immunohistochemistry was performed on liver specimens of WD patients (n = 64) and control cases (n = 160) including acute liver failure, steatotic liver disease, autoimmune hepatitis, normal liver, primary biliary cholangitis, primary and secondary sclerosing cholangitis, and progressive familial intrahepatic cholestasis. The optimal cutoff for detection of WD was determined by receiver operating characteristic (ROC) analysis.. At least moderate staining in >50% of hepatocytes was observed in 81% of analysed liver specimens (n = 56/69) of WD patients, while only five control cases showed this staining pattern. The sensitivity, specificity, and accuracy for a new diagnosis of WD were 85.7%, 96.9%, and 94.9%, respectively. Sensitivity in nonfibrotic patients was 70.6% and this MT pattern was robust in small biopsies. The hepatic copper concentration was similar between MT-positive and MT-negative liver samples (P > 0.05). Zinc treatment may induce hepatocellular MT expression. Kayser-Fleischer rings (50% versus 15%) and neurologic disorders (50% versus 13%) were significantly more prevalent in MT-negative compared to MT-positive WD patients, respectively.. MT immunostaining is an excellent biomarker for histological diagnosis of WD, should be incorporated in the diagnostic work-up of patients with potential WD, and is useful in a modified Leipzig score.

Topics: Copper; Hepatocytes; Hepatolenticular Degeneration; Humans; Liver; Metallothionein

Diagnosis of Wilson disease (WD) can be difficult because of its protean clinical presentations, but early diagnosis is important because effective treatment is available and can prevent disease progression. Similarly, diagnosis of WD on liver biopsy specimens is difficult due to the wide range of histologic appearances. A stain that could help identify WD patients would be of great value. The goal of this study was to use mass spectrometry-based proteomics to identify potential proteins that are differentially expressed in WD compared to controls, and could serve as potential immunohistochemical markers for screening. Several proteins were differentially expressed in WD and immunohistochemical stains for two (metallothionein (MT) and cytochrome C oxidase copper chaperone (COX17)) were tested and compared to other methods of diagnosis in WD including copper staining and quantitative copper assays. We found diffuse metallothionein immunoreactivity in all liver specimens from patients with WD (n = 20); the intensity of the staining was moderate to strong. This staining pattern was distinct from that seen in specimens from the control groups (none of which showed strong, diffuse staining), which included diseases that may be in the clinical or histologic differential of WD (steatohepatitis (n = 51), chronic viral hepatitis (n = 40), autoimmune hepatitis (n = 50), chronic biliary tract disease (n = 42), and normal liver (n = 20)). COX17 immunostain showed no significant difference in expression between the WD and control groups. MT had higher sensitivity than rhodanine for diagnosis of WD. While the quantitative liver copper assays also had high sensitivity, they require more tissue, have a higher cost, longer turnaround time, and are less widely available than an immunohistochemical stain. We conclude that MT IHC is a sensitive immunohistochemical stain for the diagnosis of WD that could be widely deployed as a screening tool for liver biopsies in which WD is in the clinical or histologic differential diagnosis.

Topics: Coloring Agents; Copper; Hepatolenticular Degeneration; Humans; Immunohistochemistry; Liver; Metallothionein

Wilson disease is an autosomal recessive genetic disorder caused by loss-of-function mutations in the P-type copper ATPase, ATP7B, which leads to toxic accumulation of copper mainly in the liver and brain. Wilson disease is treatable, primarily by copper-chelation therapy, which promotes copper excretion. Although several de-coppering drugs are currently available, their Cu(I)-binding affinities have not been quantitatively characterized. Here we determined the Cu(I)-binding affinities of five major de-coppering drugs - D-penicillamine, trientine, 2,3-dimercapto-1-propanol, meso-2,3-dimercaptosuccinate and tetrathiomolybdate - by exploring their ability to extract Cu(I) ions from two Cu(I)-binding proteins, the copper chaperone for cytochrome c oxidase, Cox17, and metallothionein. We report that the Cu(I)-binding affinity of these drugs varies by four orders of magnitude and correlates positively with the number of sulfur atoms in the drug molecule and negatively with the number of atoms separating two SH groups. Based on the analysis of structure-activity relationship and determined Cu(I)-binding affinity, we hypothesize that the endogenous biologically active substance, α-lipoic acid, may be suitable for the treatment of Wilson disease. Our hypothesis is supported by cell culture experiments where α-lipoic acid protected hepatic cells from copper toxicity. These results provide a basis for elaboration of new generation drugs that may provide better therapeutic outcomes.

Topics: Apoptosis; Carrier Proteins; Cell Line; Cell Proliferation; Chelating Agents; Copper; Copper Transport Proteins; Hepatocytes; Hepatolenticular Degeneration; Humans; Metallothionein; Penicillamine; Thioctic Acid; Trientine

Different mutations in the copper transporter gene Atp7b are identified as the primary cause of Wilson's disease. These changes result in high copper concentrations especially in the liver and brain, and consequently lead to a dysfunction of these organs. The Atp7

Topics: Animals; Copper; Copper-Transporting ATPases; Duodenum; Hepatolenticular Degeneration; Humans; Liver; Metallothionein; Mice; Mice, Knockout

Wilson disease (WD) is an autosomal recessive disorder caused by mutation in the ATP7B gene that affects copper transport in the body. ATP7B mutation damages copper transporter function, ultimately resulting in excessive copper accumulation and subsequent toxicity in both the liver and brain. Mechanisms of copper toxicity, however, are not well defined. The Atp7b-/- mouse model is well-characterized and presents a hepatic phenotype consistent with WD. In this study, we found that the untreated Atp7b-/- mice accumulate approximately 2-fold excess hepatic zinc compared to the wild type. We used targeted transcriptomics and proteomics to analyze the molecular events associated with zinc and copper accumulation in the Atp7b-/- mouse liver. Altered gene expression of Zip5 and ZnT1 zinc transporters indicated a transcriptional homeostatic response, while increased copper/zinc ratios associated with high levels of metallothioneins 1 and 2, indicated altered Zn availability in cells. These data suggest that copper toxicity in Wilson disease includes effects on zinc-dependent proteins. Transcriptional network analysis of RNA-seq data reveals an interconnected network of transcriptional activators with over-representation of zinc-dependent and zinc-responsive transcription factors. In the context of previous research, these observations support the hypothesis that mechanisms of copper toxicity include disruption of intracellular zinc distribution in liver cells. The translational significance of this work lies in oral zinc supplementation in treatment for WD, which is thought to mediate protective effects through the induction of metallothionein synthesis in the intestine. This work indicates broader impacts of altered zinc-copper balance in WD, including global transcriptional responses and altered zinc balance in the liver.

Topics: Animals; Copper; Copper-Transporting ATPases; Disease Models, Animal; Gene Regulatory Networks; Hepatolenticular Degeneration; Liver; Metallothionein; Mice; Mice, Knockout; Zinc

We have developed an easy and specific enzyme-linked immunoassay (ELISA) for the simultaneous determination of serum metallothinein-1 (MT-1) and 2 (MT-2) in both humans and experimental animals. A competitive ELISA was established using a specific polyclonal antibody against rat MT-2. The antibody used for this ELISA had exhibited the same cross-reactivity with MT in humans and experimental animals. The NH2 terminal peptide of MT containing acetylated methionine was shown to be the epitope of this antibody. The reactivity of this ELISA system with the liver, kidney and brain in MT1/2 knock-out mice was significantly low, but was normal in an MT-3 knock-out mouse. The lowest detection limit of this ELISA was 0.6ng/ml and the spiked MT-1was fully recovered from the plasma. We investigated the normal range of MT1/2 (25-75%tile) in 200 healthy human serum and found it to be 27-48ng/ml, and this was compared with the serum levels in various liver diseases. The serum MT1/2 levels in chronic hepatitis C (HCV) patients were significantly lower than healthy controls and also other liver diseases. In the chronic hepatitis cases, the MT1/I2 levels increased gradually, followed by the progression of the disease to liver cirrhosis and hepatocellular carcinoma. In particular, we found significantly elevated MT1/2 plasma levels in Wilson's disease patients, levels which were very similar to those in the Long-Evans Cinnamon (LEC) rat (model animal of Wilson's disease). Furthermore, a significantly elevated MT1/2 level was found in patients with Menkes disease, an inborn error of copper metabolism such as Wilson's disease.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Animals; Child; Child, Preschool; Enzyme-Linked Immunosorbent Assay; Female; Hepatolenticular Degeneration; Humans; Male; Menkes Kinky Hair Syndrome; Metallothionein; Metallothionein 3; Mice, Knockout; Middle Aged; Young Adult

We propose a conclusive difference observed between the excitation conditions required to observe porphyrins and copper-metallothioneins in cells and/or tissues using an ordinary fluorescence microscope. We have emphasized the importance of examining the spectral properties of the emissions to avoid any serious mistakes such as confusing porphyrins with copper-metallothioneins in the liver and kidneys. However, microspectrophotometry is not a conventional method for either histochemical, cytochemical, or pathological studies because microspectrophotometers are both expensive and difficult to operate. Therefore, we demonstrate a simple comparative method using ordinary excitation filter arrangements. When using our technique, it becomes possible to optically discriminate more accurately between the autofluorescence properties arising from porphyrins and those arising from copper-metallothioneins. We would like to name our simple technique "Triple Observation Method (TOM)".

Topics: Animals; Child; Color; Copper; Hepatolenticular Degeneration; Humans; Liver; Male; Metallothionein; Microscopy, Fluorescence; Optical Phenomena; Porphyrins; Rats; Spectrometry, Fluorescence

Tetrathiomolybdate (TTM) is a powerful and selective copper (Cu) chelator that is used as a therapeutic agent for Wilson disease. TTM is the sole agent that can remove Cu bound to metallothionein (MT) in the livers of Long-Evans rats with a cinnamon-like coat color (LEC rats). However, the administration of excess TTM causes the deposition of Cu and molybdenum (Mo) in the liver. In the present study, the effect of hepatic glutathione (GSH) depletion on the removal of Cu from the livers of LEC rats was evaluated to establish an effective therapy by TTM. Pretreatment with l-buthionine sulfoximine (BSO), a depletor of GSH in vivo, reduced the amounts of Cu and Mo excreted into both the bile and the bloodstream, and increased the amounts of Cu and Mo deposited in the livers of LEC rats in the form of an insoluble complex 4h after the TTM injection. The results suggest that GSH depletion creates an oxidative environment in the livers of LEC rats, and the oxidative environment facilitates the insolubilization of Cu and Mo in the livers of LEC rats after the TTM injection. Therefore, the effect of TTM on the removal of Cu from the liver was reduced in the oxidized condition. Wilson disease patients and LEC rats develop liver injury caused by oxidative damage. From a clinical viewpoint, increasing in the GSH concentration is expected to enhance the effect of TTM.

Topics: Animals; Buthionine Sulfoximine; Chelating Agents; Copper; Enzyme Inhibitors; Glutathione; Hepatolenticular Degeneration; Humans; Liver; Male; Metallothionein; Molybdenum; Oxidation-Reduction; Rats; Rats, Inbred LEC; Rats, Wistar; Time Factors

Exclusive monotherapy with zinc in symptomatic Wilson disease is controversial. Seventeen symptomatic patients with Wilson disease were treated with zinc only. The mean age at diagnosis and start of treatment was 18 years (range 13-26) with approximately half presenting as adolescents. Presentation was exclusively hepatic, exclusively neurologic, and combined in seven, five, and five patients, respectively. The median follow-up was 14 years (range 2-30). At baseline, two of the 12 patients with hepatic disease exhibited decompensated cirrhosis, five exhibited compensated cirrhosis, and five had less severe disease. Both patients with decompensated cirrhosis improved to a compensated state after initiation of therapy. Two of the five patients with initial compensated cirrhosis progressed to decompensated state, and three remain stable. Three of the five patients with moderate or mild liver disease remain stable and two improved. Apart from decreasing bilirubin levels, no significant changes occurred in the liver biochemistry or function during long-term follow-up. Nine of 10 neurologic patients improved markedly and one deteriorated. Two patients with exclusively neurologic presentation developed liver disease during zinc treatment. Two patients with exclusively hepatic presentation developed mild neurologic symptoms. According to 24-hour urinary copper excretions (213 +/- 38 versus 91 +/- 23 microg: P = 0.01) and serum non-ceruloplasmin-bound copper concentrations (11 +/- 2 versus 7 +/- 1 microg/dL: P = 0.1) at the end of follow-up, the efficacy of decoppering was less in the exclusively hepatic than in the neurologic group. The prescribed zinc dose and 24-hour urinary zinc excretions tended to be less in the exclusively hepatic group.. The outcome of exclusive zinc therapy is generally good in cases of neurologic disease. A less satisfactory outcome in hepatic disease may relate to less efficient decoppering.

Topics: Adolescent; Adult; Bilirubin; Chelating Agents; Copper; Dose-Response Relationship, Drug; Female; Follow-Up Studies; Hepatolenticular Degeneration; Humans; Liver; Longitudinal Studies; Male; Metallothionein; Penicillamine; Trace Elements; Treatment Outcome; Young Adult; Zinc

Topics: Copper; Hepatocytes; Hepatolenticular Degeneration; Humans; Liver Cirrhosis, Biliary; Metallothionein; Microscopy, Fluorescence

Topics: Chelating Agents; Copper; Dose-Response Relationship, Drug; Hepatolenticular Degeneration; Humans; Liver; Metallothionein; Penicillamine; Trace Elements; Treatment Outcome; Zinc

Zinc therapy has replaced penicillamine as first-line therapy for Wilson's disease. New guidelines reflect the paradigm shift in treatment that has occurred in recent years. In the old paradigm, Wilson's disease was seen as genetic disorder associated with the accumulation of copper in the liver and in other organs once the liver had become overloaded with copper. When left untreated, the disease was regarded as uniformly fatal. The old treatment guidelines advised, 'decoppering' with penicillamine because this chelating agent was considered effective in restoring most patients to health. Before the start of treatment, patients were warned that their symptoms could worsen during the first weeks or months of therapy, so as to prevent them from abandoning penicillamine therapy in dismay. In the new paradigm, Wilson's disease is seen as a hereditary disorder associated with copper intoxication. The essence of symptomatic Wilson's disease is poisoning by free copper in the blood, that is, by copper that is not bound to ceruloplasmin. This form of copper is toxic, whereas accumulated copper and copper that is bound to ceruloplasmin or metallothionein is not. The treatment of symptomatic Wilson's disease is no longer aimed at 'decoppering', the removal of accumulated copper, but at the normalization of the free copper concentration in blood, to reverse the copper poisoning. This can be achieved safely and effectively with zinc therapy. Zinc induces metallothionein, a highly effective detoxification protein that binds copper. Oral zinc therapy leads to storage of metallothionein-bound copper in the mucosa of the gut and to the excretion of copper via the stools. New treatment guidelines advise against the use of chelating agents as initial treatment because they may aggravate copper intoxication and cause iatrogenic deterioration.

Topics: Administration, Oral; Adolescent; Adult; Chelating Agents; Copper; Female; Hepatolenticular Degeneration; Humans; Metallothionein; Zinc

Wilson's disease (WD) with extensive cortico-subcortical lesions represents a rare neuropathological subgroup, the pathogenesis of which is not clearly determined. We report two new cases with identical lesions. In the families of each of the patient, there were mutations in the ATPase7B gene, especially in the family of proband 1, and in the first cousin of proband 2. These cases included massive destruction of the white matter in superior gyri, mostly frontal, extending to the deep cortex with neuronal loss and capillary proliferation. Astrocytes were of Alzheimer type 1 and 2; and type 1 were labeled by anti-metallothionein. Opalski cells were abundant and their macrophagic lineage was confirmed by immunostaining. Among the possible mechanisms proposed, the role of vascular factors and penicillamine treatment could be excluded. Cerebral copper content in white matter and putamen of case 1 was at the same level as in common WD but accumulation of unbound copper in the white matter was a distinctive feature, which suggested a pathological neurotoxic effect.

Topics: Adenosine Triphosphatases; Adult; Astrocytes; Cation Transport Proteins; Cerebral Cortex; Copper; Copper-Transporting ATPases; Female; Hepatolenticular Degeneration; Humans; Liver; Macrophages; Male; Metallothionein; Pedigree; Putamen

The effect of oral zinc (Zn) treatment was studied in the liver, kidneys and intestine of Long-Evans Cinnamon (LEC) rats in relation to metals interaction and concentration of metallothionein (MT) and glutathione (GSH). We also investigated the change in the activity of antioxidant enzymes and determined the biochemical profile in the blood and metal levels in urine. We showed that the Zn-treated group had higher levels of MT in the hepatic and intestinal cells compared to both untreated and basal groups. Tissue Zn concentrations were significantly higher in the Zn-treated group compared to those untreated and basal, whereas Cu and Fe concentrations decreased. The antioxidant enzyme activities in the Zn-treated group did not change significantly with respect to those in the basal group, except for hepatic glutathione peroxidase activity. Moreover, the biochemical data in the blood of Zn-treated group clearly ascertain no liver damage. These observations suggest an important role for Zn in relation not only to its ability to compete with other metals at the level of absorption in the gastrointestinal tract producing a decrease in the hepatic and renal Cu and Fe deposits, but also to MT induction as free radical scavenger.

Topics: Animals; Catalase; Copper; Disease Models, Animal; Glutathione; Hepatolenticular Degeneration; Intestinal Mucosa; Intestines; Iron; Kidney; Liver; Male; Metallothionein; Rats; Rats, Inbred LEC; Superoxide Dismutase; Zinc

Soy-protein isolate (SPI) enhances liver cell damage in Long-Evans rats with a cinnamon-like coat color (LEC rats), which have a defect in Atp7b, the Wilson disease gene. Animals administered an SPI-diet from an age of six weeks died significantly earlier than those administered a control-diet, AIN-93G, from severe liver cell damage associated with jaundice. Since the liver copper level was higher with the SPI-diet than the control-diet, one of the reasons for SPI-toxicity to LEC rats might be due to the higher uptake of copper into liver cells. In the present study, liver levels of glutathione, and liver and intestinal mRNA and protein levels were determined for metallothionein, MT-1 and MT-2. Furthermore, liver and intestinal mRNA expression for the high affinity copper transporter, Ctr1, was determined. None of the parameters showed any significant differences between the SPI-diet and control-diet groups, except for Ctr1 mRNA levels in the liver. It is thus suggested that SPI enhances liver cell copper uptake through induction of Ctr1 expression and this might be the mechanism underlying increased liver damage in LEC rats.

Topics: Animals; Cation Transport Proteins; Copper Transporter 1; Disease Models, Animal; Glutathione; Glutathione Disulfide; Hepatolenticular Degeneration; Liver; Membrane Proteins; Metallothionein; Rats; RNA, Messenger; Soybean Proteins

Copper is both essential for life and toxic. Aberrant regulation of copper at the level of intracellular transport has been associated with inherited diseases, including Wilson's disease (WND) in humans. WND results in accumulation of copper and the copper and zinc-binding protein metallothionein (MT) in liver and other tissues, liver degeneration, and neurological dysfunction. The toxic milk (TX) mutation in mice results in a phenotype that mimics human WND, and TX has been proposed to be a model of the disease. We characterized TX mice as a model of altered metal ion and MT levels during development, and after treatment with the metal ion chelators tetrathiomolybdate (TTM) and deferiprone (L1). We report that hepatic, renal and brain copper and MT are elevated in TX mice at 3 and 12 months of age. Zinc was significantly higher in TX mouse liver, but not brain and kidney, at both time points. Nodules appeared spontaneously in TX mouse livers at 8-12 months that maintained high copper levels, but with more normal morphology and decreased MT levels. Treatment of TX mice with TTM significantly reduced elevated hepatic copper and MT. Transient increases in blood and kidney copper accompanied TTM treatment and indicated that renal excretion was a significant route of removal. Treatment with L1, on the other hand, had no effect on liver or kidney copper and MT, but resulted in increased brain copper and MT levels. These data indicate that TTM, but not L1, may be useful in treating diseases of copper overload including WND.

Topics: Animals; Copper; Deferiprone; Disease Models, Animal; Hepatolenticular Degeneration; Metallothionein; Mice; Mice, Mutant Strains; Molybdenum; Phenotype; Pyridones

The effect of oral Zn treatment was studied in the liver and kidneys of 26 male Long-Evans Cinnamon (LEC) rats (mutant animals, 5 weeks old) in relation to both the interaction between Zn and Cu and the localisation and concentration of metallothionein (MT). Rats receiving 80 mg zinc acetate daily by gavage and control rats receiving no treatment were killed after 1 or 2 weeks. By immunohistochemical and analytical chemical techniques we revealed that treated rats had higher levels of MT in the hepatic and renal cells compared to untreated ones. Tissue Zn concentrations were significantly higher in treated rats compared to untreated whereas Cu concentrations decreased in the liver and kidneys as indicated by analytical chemical analyses. MT levels also decreased with treatment period. A histochemical procedure, obtained using autofluorescence of Cu-metallothioneins, confirms these findings: after 2 weeks, the signal decreased in both the liver and kidney sections. This gives a greater understanding of the mechanism of Cu metabolism in the two tissues considered. These results suggest that Zn acts both to compete for absorption on the luminal side of the intestinal epithelium and to induce the synthesis of MT.

Topics: Animals; Copper; Disease Models, Animal; Drug Interactions; Hepatolenticular Degeneration; Immunohistochemistry; Kidney; Liver; Male; Metallothionein; Microscopy, Fluorescence; Rats; Rats, Inbred LEC; Zinc

Redox properties of metallothioneins (MTs) and Cu in the cytosol from Long-Evans Cinnamon (LEC) rat livers 13 weeks after birth were investigated. MTs from LEC rat livers contain 8 g atoms of Cu and 1 g atom of Zn per mole of protein (Cu(I)8-MTs). Titration of Cu(I)8-MTs with CuCl2 indicates that Cu(I)8-MTs were able to reduce further 2-g atoms of cupric ions per mole MTs as bound form. Hg2+-induced hydroxyl radical generation from Cu(I)8-MTs was demonstrated by ESR using the spin trap, 5,5-dimethyl-1-pyrroline N-oxide (DMPO). The intensity of DMPO-OH signal from Cu-loaded MTs was increased with the increasing number of Cu in MTs. The used cytosol fraction contained 1.37 mM total Cu and 5 mM DTNB titrable-SH groups has a potential to reduce 2 mM CuCl2. No ESR signal due to Cu2+ was also detected with LEC rat liver cytosol, whereas strong Cu2+ signal appeared by the addition of HgCl2. The rate constants for the reaction of Cu(I)8-MTs with superoxide and hydroxyl radicals were estimated to be 2 x 10(6) and > or = 10(12) M(-1)s(-1), respectively, from competition kinetics. Cu2+-catalyzed oxidation of DNA was strongly inhibited both in the presence of Cu-unsaturated MTs and GSH. The results suggest that Cu(I)8-MTs from LEC rat livers just before hepatitis still act as antioxidants.

Topics: Animals; Antioxidants; Binding, Competitive; Cadmium Chloride; Copper; Cyclic N-Oxides; Cytosol; DNA; Dose-Response Relationship, Drug; Electron Spin Resonance Spectroscopy; Glutathione; Hepatolenticular Degeneration; Hydroxyl Radical; Liver; Male; Mercuric Chloride; Metallothionein; Oxidation-Reduction; Rats; Rats, Inbred LEC; Reactive Oxygen Species; Superoxide Dismutase

A neuropathological study of Alzheimer type I (Alz I) and Alzheimer type II (Alz II) as well as Opalski (Opl) cells was performed serially on brain tissue from nine autopsied Wilson's disease (WD) cases. Conventional staining methods (Kluver-Barrera, HE, PAS) and immunocytochemical techniques (anti-GFAP and anti-Metallothionein-MT) were used. On conventional staining, each of the studied abnormal cell types retained common morphological characteristics of astroglia, and concurrently demonstrated its own distinctive features, specific only for a given cell type. Anti-GFAP staining revealed positive immunoreactivity of Alz I and Opl cells, and its absence in Alz II cells. On anti-MT staining both the cytoplasm and nucleus of Alz I and Opl cells showed positivity whereas in Alz II cells the cytoplasm was positive in contrast to the negative nucleus. The results of our study confirm the hypothesis of the astroglial origin of all three types of cells. The lack of immunoreactivity for GFAP and similar immunocytochemical staining patterns for MT in Alz II cells and protoplasmic astrocytes may suggest that Alz II cells originate from the protoplasmic type of astroglia. The fact that Alz I and Opl cells resemble fibrous astrocytes in their immunoreactive positivity for GFAP may lead to a supposition that they originate from the fibrous type of astroglia. MT-positive expression by the three abnormal cell types suggests that they may be involved in the process of copper detoxification in WD.

Topics: Adolescent; Adult; Astrocytes; Brain; Female; Glial Fibrillary Acidic Protein; Hepatolenticular Degeneration; Humans; Male; Metallothionein

Topics: Hepatolenticular Degeneration; Humans; Intestine, Small; Metallothionein; Zinc

Wilson's disease is effectively treated by zinc administration which, in vitro, increases metallothionein concentrations. To ascertain whether the latter also occurs in humans we measured metallothionein and trace element concentrations in the duodenal mucosa of 15 Wilson's disease patients: 12 treated with zinc sulphate, two treated with penicillamine, and one not yet on treatment. The control group consisted of 17 patients with dyspepsia, who underwent the same study protocol.. Metallothionein and trace element concentrations were measured in duodenal mucosa biopsies according to the silver-saturation hemolysate method and atomic absorption spectrophotometry.. Metallothionein concentrations increased by 1500% after zinc and 150% after penicillamine in Wilson's disease patients, with respect to controls who had negative endoscopy and Wilson's disease patients who were not treated. A significant correlation was found between metallothionein and duodenal zinc concentrations. Mucosal iron concentration increased in Wilson's disease patients whether they were treated with zinc or penicillamine. Duodenum with duodenitis also had significantly increased iron levels compared with normal duodenum.. Zinc administration increases intestinal metallothionein in Wilson's disease patients. The blockade of copper absorption and its elimination in the stools on desquamation of the intestinal cells probably explains one of the mechanisms underlying the effect of zinc treatment. Despite normal endoscopy, Wilson's disease patients present increased mucosal iron concentrations similar to those in controls with duodenitis. Metallothionein may therefore prevent oxidative damage caused by metal toxicity.

Topics: Adult; Case-Control Studies; Chelating Agents; Copper; Duodenitis; Duodenum; Female; Hepatolenticular Degeneration; Humans; Intestinal Mucosa; Iron; Male; Metallothionein; Penicillamine; Zinc Sulfate

The present work was performed to examine the effect of tetrathiomolybdate on Cu and Fe metabolism, especially redistribution of Cu and Fe in the brains of Long-Evans Cinnamon rats, with inherently abnormal Cu deposition in the liver. The drug was injected subcutaneously at 5 mg/kg of body weight twice a week for 65 days (total dose of 20 mg) into 40-day-old Long-Evans Cinnamon rats. In Long-Evans Cinnamon rats treated with tetrathiomolybdate, the hepatic Cu concentration was 60 microg/g wet weight, compared to 170 microg/g in untreated rats. In seven brain regions (cerebellum, medulla oblongata, hypothalamus, striatum, midbrain, hippocampus and cortex) of the Long-Evans Cinnamon rats treated with tetrathiomolybdate. the Cu concentration (1.5 to 2.3 microg/g) was slightly lower (1.6 to 2.7 microg/g) than in untreated rats. A significant difference between the two groups was found only in the midbrain. Brain Fe concentrations in regions other than the striatum were not changed significantly by the tetrathiomolybdate injections. The hepatic Fe concentration was about 120 microg/g in Long-Evans Cinnamon rats without tetrathiomolybdate. Tetrathiomolybdate injection further increased the concentration to about 250 microg/g. Our results indicated that subcutaneous tetrathiomolybdate injection did not have an effect that stimulated redistribution of Cu and Fe in the seven brain regions examined, although hepatic Cu was markedly decreased and the removed Cu was deposited in kidneys, spleen and testes. The increased hepatic Fe level should be taken into account when considering side effects of the compound.

Topics: Animals; Brain; Ceruloplasmin; Copper; Disease Models, Animal; Enzyme-Linked Immunosorbent Assay; Ferritins; Hepatolenticular Degeneration; Injections, Subcutaneous; Iron; Kidney; Liver; Male; Metallothionein; Molybdenum; Rats; Rats, Inbred LEC

Rats of Long-Evans Cinnamon (LEC) strain were used as a hepatorenal syndrome model of fulminant Wilson's disease. Copper levels in the kidneys increased markedly from 16 to 126 microg Cu/g from 12 to 16 weeks, and remained at the same level at 16 and 19 weeks when the rats suffered from severe renal dysfunction and also at 20 weeks in some other normal rats. The above findings imply that the renal dysfunction may have been induced independently of the copper level in the kidneys. The present study suggested the following mechanism: immediately after copper-induced hepatic dysfunction, plasma copper-metallothionein (CuMT), which was released from the liver, became elevated. The elevation was closely related to the increases in alkaline phosphatase, glucose and amino acids, all in the urine. The above findings suggest that plasma CuMT, which was released from the liver into the blood upon copper-induced hepatic dysfunction, was subsequently filtered at the glomeruli due to its smaller molecular weight, and then caused dysfunction of the brush border membrane of the renal proximal tubules probably after splitting into radical copper and amino acids in acidic vesicles close to the membrane. The critical concentration of plasma CuMT required to induce renal dysfunction was estimated as 1 microg Cu/l.

Topics: Animals; Copper; Disease Models, Animal; Hepatolenticular Degeneration; Hepatorenal Syndrome; Jaundice; Kidney; Liver; Male; Metallothionein; Rats; Rats, Long-Evans

To study effects of dietary Cu and Fe levels on the onset of hepatitis in Long-Evans Cinnamon (LEC) rats, female rats (40 days old) were fed a semipurified diet containing 0.1 or 10 mg Cu/kg and 1.5 or 150 mg Fe/kg in a 2 x 2 factorial arrangement for 35 days. At 75 days after birth, LEC rats (+Cu-Fe) fed a Cu-sufficient but Fe-deficient diet (Cu, 10 mg/kg; Fe, 1.5 mg/kg) showed jaundice, with lethargy, anorexia, and malaise. The biochemical variables relating to liver function were significantly increased compared to three other groups, a Cu- and Fe-deficient (-Cu-Fe) group, a Cu-deficient but Fe-sufficient (-Cu+Fe) group, and a Cu and Fe sufficient (+Cu+Fe) group. Furthermore, the +Cu-Fe rat liver showed massive necrosis with huge nuclei. The other three groups presented no biochemical and histological findings of hepatitis. Hepatic Cu and metallothionein concentrations were 289 +/- 87 (mean +/- SD) microg/g liver and 8.7 +/- 1.8 mg/g liver, respectively, in the +Cu-Fe rats. However, in the +Cu+Fe group the values were 196 +/- 28 microg Cu/g liver and 10.8 +/- 1.0 mg/g liver. Hepatic Fe deposition was not influenced significantly by the dietary Cu level. The +Cu-Fe group with jaundice showed the highest free Cu concentration in the liver among the four groups, but the hepatic free Fe concentration was similar to those in the -Cu+Fe and +Cu+Fe groups. Our results indicate that an Fe-deficient diet enhances the deposition of hepatic Cu due to increased absorption of Cu from the gastrointestinal tract. This deposition stimulated the onset of hepatitis.

Topics: Animals; Body Weight; Copper; Female; Ferritins; Hepatitis, Animal; Hepatolenticular Degeneration; Intestinal Absorption; Iron; Iron Deficiencies; Iron, Dietary; Liver; Metallothionein; Rats; Rats, Long-Evans; Specific Pathogen-Free Organisms

In the study described here we have revealed an abnormal accumulation of porphyrin derivatives in the kidneys of Long-Evans Cinnamon (LEC) rats, an animal model for human Wilson's disease. In addition, we have confirmed that the derivatives emitted red-orange light in renal sections under UV excitation. This renal red-orange emission has previously been identified as luminescence from cuprous metallothioneins [Cu(I)-MTs], which also accumulate in both the kidneys and liver of LEC rats. In this study, we measured the emission spectra of the luminescence in the kidneys using microspectrophotometry. The spectra of the renal red-orange emission resembled those of porphyrin derivatives rather than those of Cu(I)-MTs. We then extracted these derivatives from the kidneys. An abundance of porphyrin derivatives was established. A significant increase in the levels of the derivatives in the liver and urine of the LEC rats was also confirmed. These results provide evidence of a heme-metabolism abnormality in LEC rats.

Topics: Animals; Copper; Disease Models, Animal; Hepatolenticular Degeneration; Kidney; Male; Metallothionein; Microscopy, Fluorescence; Microspectrophotometry; Porphyrins; Rats; Rats, Mutant Strains

The Long-Evans cinnamon (LEC) rat has a mutation homologous to the human Wilson's disease gene, leading to copper-induced hepatotoxicity. The mechanism of how excess copper damages the liver or what chemical form of copper is toxic is still unclear.. In liver cytosol, copper levels were highest just before the onset of hepatitis and declined thereafter. In cytosol, total copper was bound to metallothionein (MT). Considerable amounts of both copper and iron accumulated in lysosomes with increasing age and development of liver damage. Lysosomal levels of presumably reactive non-MT-bound copper were increased. In severely affected livers, large amounts of copper were associated with insoluble material of high density which, upon ultrastructural information, was found to be derived from the lysosomes of Kupffer cells. This copper-rich material is considered to consist of polymeric degradation products of copper-MT.. We suggest that chronic copper toxicity in LEC rats involves the uptake of copper-loaded MT into lysosomes, where it is incompletely degraded and polymerizes to an insoluble material containing reactive copper. This copper, together with iron, initiates lysosomal lipid peroxidation, leading to hepatocyte necrosis. Subsequent to phagocytosis by Kupffer cells, the reactive copper may amplify liver damage either directly or through stimulation of these cells.

Topics: Animals; Copper; Cytosol; Female; Hepatitis, Animal; Hepatolenticular Degeneration; Humans; Kupffer Cells; Liver; Lysosomes; Male; Metallothionein; Mitochondria, Liver; Rats; Rats, Mutant Strains; Rats, Wistar

Topics: Animals; Copper; Disease Models, Animal; Hepatolenticular Degeneration; Humans; Metallothionein; Rats; Rats, Mutant Strains

The uptake of tetrathiomolybdate (TTM) by the liver and the removal of copper (Cu) accumulating in the liver in a form bound to metallothionein (MT) by TTM were studied in Long-Evans cinnamon (LEC) rats, an animal model of Wilson disease, in order to develop better treatments for the disease and Cu toxicity. Although molybdenum (Mo) was incorporated in a dose-dependent manner into the livers of both LEC and Long-Evans agouti (LEA) rats, the original strain of LEC rats used as a reference animal, the uptake into the liver of LEC rats was 13 times higher than that in LEA rats. The concentration of Mo in the soluble fraction plateaued and it was distributed more in the insoluble fraction with a higher dose in LEC rats. The concentration of Cu in the whole livers of LEC rats was decreased by TTM in a dose-dependent manner only at lower doses. However, the concentration of Cu in the soluble fraction continued to decrease with the dose of TTM. The results can be explained in terms of complex formation. Namely, TTM forms a complex with Cu, tentatively referred to a Cu/TTM complex, that can be effluxed into the bloodstream, and then binds selectively to albumin when the dose of TTM is low. On the other hand, TTM forms an insoluble complex, named as a Cu/TTM polymer that is precipitated in the liver when the dose is high. The results further indicate that TTM taken up by a cell is immobilized in the cell through the dose-dependent formation of a complex containing Cu, Mo and sulfur (S), which causes further uptake of TTM. TTM injected into rats or incubated in vitro with serum does not remove Cu from ceruloplasmin. TTM is, thus, suggested to target a cell accumulating excess Cu as Cu-MT, and to remove Cu selectively without interacting with Cu in Cu-enzymes. The results indicate that TTM is taken up by the liver depending on the amount of Cu accumulating in the form of MT, and then Cu is effluxed together with Mo in the form of Cu/TTM complex into the bloodstream.

Topics: Animals; Biological Transport, Active; Ceruloplasmin; Copper; Disease Models, Animal; Female; Hepatolenticular Degeneration; Liver; Metallothionein; Molybdenum; Protein Binding; Rats; Rats, Mutant Strains

Copper (Cu) was selectively removed from metallothionein (MT) in the liver of LEC rats (Long-Evans rats with a cinnamon-like coat color) in vivo and in vitro by tetrathiomolybdate (TTM). Female LEC rats were injected intraperitoneally with TTM at a dose of 10 mg/kg body weight for 8 consecutive days. More than 2/3 of the Cu accumulating in the liver was removed by TTM treatment 24 h after the last injection. Although most Cu was bound to MT in the soluble fraction before TTM treatment, the Cu remaining in the liver was present almost exclusively in the non-soluble fraction together with molybdenum (Mo). Cu,Zn,Cd-MT was separated from the liver of LEC rats that had been injected with cadmium (Cd) and reacted with TTM at mol ratios of 0, 0.25, 0.50, 1.0, 2.0 and 4.0 to Cu bound to MT for 10 min at 37 degrees C. When TTM was added at a mol ratio of less than 1.0, a Cu,Zn,Cd-MT/TTM complex was detected, while addition of TTM at a mol ratio of greater than 1.0 selectively removed Cu from MT and produced a Cu/TTM complex via liberation of Zn,Cd-MT from the Cu,Zn,Cd-MT/TTM complex. Excessive TTM appeared to facilitate polymerization of the Cu/TTM complex to insoluble polymers. The dose-related formation of differing MT/TTM complexes explains the findings observed in vivo.

Topics: Animals; Cadmium; Copper; Female; Hepatolenticular Degeneration; Injections, Intraperitoneal; Kidney; Liver; Male; Mass Spectrometry; Metallothionein; Metals; Molybdenum; Rats; Rats, Mutant Strains; Zinc

Long-Evans Cinnamon (LEC) rats, characterized by a gross accumulation of hepatic Cu and the spontaneous onset of hepatitis, have been established to be an animal model for Wilson disease. They were used to estimate the relationships among copper (Cu), metallothionein (MT), and reduced glutathione (GSH) in biliary excretion in this study. Even though a huge amount of MT existed in the LEC rat liver (5016 micrograms/g liver) compared to that (63 micrograms/g liver) of controls (Fischer rats), the biliary excretion of MT (65 ng/ml bile) did not reflect the accumulated MT level in LEC rats. It seems likely that MT does not excrete intrinsically into the bile. Biliary excretion of Cu (0.17 microgram/ml) in LEC rats was significantly lower than that (0.57 microgram/ml) in Fischer rats. The difference in biliary excretion of GSH between the two groups was significant but slight. The reduced excretion of GSH into bile in LEC rats may be due to increased hepatic gamma-glutamyltransferase but not to hepatic GSH levels. There were no differences in biliary potassium and inorganic phosphorous between the two groups. On the other hand, excretion of lysosomal enzymes such as beta-N-acetylglucosaminidase into bile was much lower in LEC rats (15.6 units/liter) than in controls (42.5 units/liter). The defective biliary excretion of Cu may be due to impaired lysosomal exocytosis, rather than canalicular membrane impairment. The LEC rat is very useful for research into the dynamics of metal excretion via the hepatobiliary system.

Topics: Acetylglucosaminidase; Aminopeptidases; Animals; Bile; Copper; Disease Models, Animal; Female; gamma-Glutamyltransferase; Glutathione; Hepatolenticular Degeneration; Metallothionein; Rats; Rats, Inbred F344; Rats, Mutant Strains

We have studied the copper and metallothionein (MT) in culture skin fibroblasts of patients and heterozygotes with Wilson's disease (WD) and controls (5 cases each) after incubation in mediums containing various concentrations of copper (C1: 15.74 mumol/L, C2: 78.70 mumol/L, C3: 157.38 mumol/L, C4: 314.76 mumol/L). The results are as follows: 1. In each of the three groups, the copper/protein ratio (Cu/P) in cytosols of 1-5 passages is significantly higher than that of 6-10, 11-15, 16-20 passages. There are no significant differences among 6-10, 11-15 and 16-20 passages. 2. In standard medium, Cu/P in cytosols of three groups are not significantly different, but Cu/P of patients is significantly higher than that of the other two groups after incubation in C4 medium for 12 or 24 hours. 3. After incubation in C1, C2, C3 and C4 mediums respectively, the Cu/P in cytosols of the three groups only increased in C4 medium with time (within 72 hours). It is higher in the patient group than the other two groups. 4. In the three groups, cytosol copper distributed similarly in two peaks after Sephadex G-75 chromatography, which are on high molecular weight (HMW) proteins and MT fractions respectively. It remained the same after incubation in various concentrations of copper. The copper content found in MT fractions in WD patients is much higher than that of controls and heterozygotes. It is even higher after incubation in various concentrations of copper but no changes was found in controls and heterozygotes.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Adolescent; Adult; Case-Control Studies; Cells, Cultured; Child; Copper; Cytosol; Fibroblasts; Hepatolenticular Degeneration; Heterozygote; Humans; Metallothionein; Middle Aged; Molecular Weight

The LEC rat is a mutant strain displaying hereditary hepatitis, and shows abnormal accumulation of copper (Cu) similar to that occurring in Wilson's disease. We prepared a multicellular spheroid composed of LEC rat liver cells to investigate the mechanism for abnormal accumulation of Cu. These multicellular spheroids were prepared by detaching the monolayer on the collagen-conjugated thermo-responsive polymer coated culture dish at a temperature below the critical solution temperature and culturing on the non-adhesive substratum. Long-term cultured spheroids of LEC rat liver cells as well as SD rat liver cells were attempted. Non-parenchymal cells obtained by collagenase perfusion from the LEC liver were fewer than those from the SD liver. Cells from the LEC rat, over 11 weeks of age, did not form a cell sheet; however, a mixture of parenchymal cells from LEC rats over aged 11 weeks and non-parenchymal cells from SD rats of any age yielded intact spheroids. We examined the toxicity, the accumulation and distribution of Cu in spheroids. The accumulation of Cu in LEC spheroids was higher than that in SD spheroids. Results suggest that spheroids consisting of LEC liver cells are useful as an alternative model to in vivo tests to investigate the mechanism for abnormal accumulation of Cu in liver.

Topics: Animals; Copper; Hepatolenticular Degeneration; Kinetics; Liver; Male; Metallothionein; Rats; Rats, Mutant Strains; Rats, Sprague-Dawley; Spheroids, Cellular; Zinc

The siblings of patients with newly diagnosed Wilson's disease are each at 25% risk of also having this autosomal recessive disease. Screening these siblings allows their detection and institution of prophylactic therapy before they become clinically ill. Herein we report the successful treatment of 13 presymptomatic patients with zinc acetate. These patients who received zinc have been followed for 3 to 9 years. In well-complying patients, 24-hour urine copper and non-ceruloplasmin plasma copper levels have decreased over years of follow-up, consistent with the elimination of the excess easily mobilized copper (the potentially toxic copper) of the body. Effect of therapy and compliance are easily monitored by following 24-hour urine zinc and copper levels. The urine copper level is a good reflection of the body's excess load of easily mobilizable copper. It will increase if control is not adequate. A decrease in urine zinc is an early signal that the patient's compliance is not optimal. The levels of hepatic copper in response to several years of zinc therapy may remain the same, go down, or go up temporarily. This is a reflection of zinc induction of hepatic metallothionein, which sequesters copper in a non-toxic pool. Hepatic copper levels should not be used to manage therapy. Liver function is well preserved by zinc therapy, and no zinc toxicity occurred in these 13 patients. No patient developed symptoms related to Wilson's disease. We conclude that zinc acetate is a fully effective and non-toxic therapy for the prophylactic treatment of the presymptomatic Wilson's disease patient.

Topics: Adolescent; Adult; Child; Copper; Female; Hepatolenticular Degeneration; Humans; Iron; Lipids; Liver; Liver Function Tests; Male; Metallothionein; Patient Compliance; Zinc

Recently it was found that the clinical features of the LEC rat closely resemble those of human Wilson's disease. One of the characteristics of the animal is low levels of serum ceruloplasmin. Therefore, by using LEC rats, we attempted to define molecular basis of the deficiency in active site of ceruloplasmin in Wilson's disease patients. We made 3 monoclonal antibodies, ID2 against active site of ceruloplasmin, ID1 against inactive site of ceruloplasmin, and the remaining one against metallothionein. Using these monoclonal antibodies, we examined immunohistochemical stainings of LEC rat liver tissues, and compared them with those of LEA rats, as a control. ID1 stained the hepatocytes of both LEA and LEC rats, whereas ID2 stained LEA rat hepatocytes only. The results indicated that the ceruloplasmin secreted by LEC rat hepatocytes is mostly in inactive form. The antibody against metallothionein stained LEA rat hepatocytes only. This finding may also indicate that LEC rat hepatocytes express less amount of metallothionein than those of LEA rats.

Topics: Animals; Antibodies, Monoclonal; Binding Sites; Ceruloplasmin; Copper; Female; Hepatolenticular Degeneration; Humans; Immunohistochemistry; Liver; Male; Metal Metabolism, Inborn Errors; Metallothionein; Rats; Rats, Mutant Strains

Topics: Adult; Biopsy; Endoscopy; Female; Hepatolenticular Degeneration; Humans; Intestinal Mucosa; Intestines; Male; Metallothionein; Middle Aged; Zinc

In patients with primary biliary cirrhosis and Wilson's disease liver copper concentrations become elevated during the evolution of the disorder. The accumulated copper is thought to be detoxified by metallothionein, a protein which binds copper and zinc. In liver metastasis of colorectal cancer, copper and zinc concentrations are usually decreased compared to normal liver tissue, but little is known about the concomitant metallothionein levels. In the present study metallothionein concentrations were determined in archival liver samples from patients with primary biliary cirrhosis and Wilson's disease, and in both normal and malignancy-containing liver samples from patients with metastasis from a colorectal adenocarcinoma. Twenty-seven control liver samples contained 3.98 +/- 1.55 mg metallothionein/g protein. From the 21 liver samples of patients with primary biliary cirrhosis, which had a mean metallothionein concentration of 6.06 +/- 5.03 mg/g protein, 6 were above the highest control level. Liver metallothionein concentrations for the 8 patients with Wilson's disease were significantly elevated (10.98 +/- 6.93 mg/g protein, p < 0.005 vs. controls and p < 0.05 vs. primary biliary cirrhosis). In the 11 liver metastases from colorectal adenocarcinomas metallothionein concentrations (1.17 +/- 0.90 mg/g protein) were significantly (p < 0.005) lower than surrounding normal liver tissue (4.25 +/- 1.75 mg/g protein). We conclude that in primary biliary cirrhosis and Wilson's disease increased liver metallothionein concentrations may detoxify the accumulated copper. Furthermore, liver metastasis of colorectal cancer contains less metallothionein than the surrounding normal liver tissue.

Topics: Adenocarcinoma; Adult; Aged; Colorectal Neoplasms; Female; Hepatolenticular Degeneration; Humans; Liver; Liver Cirrhosis, Biliary; Liver Neoplasms; Male; Metallothionein; Middle Aged; Radioimmunoassay

In the present study we have used differential centrifugation, size exclusion chromatography, Western and Northern blotting to investigate the subcellular distribution of hepatic copper, the association of the metal with hepatic copper binding proteins and the expression of specific mRNAs for copper binding proteins in liver tissue from two patients with Wilson's disease, two patients with chronic liver disease and two patients with normal hepatic copper levels. Unlike previous studies the present results fail to show any gross differences in subcellular distribution of copper between the livers, with most of the copper being found in the soluble supernatant where it is associated with metallothionein. Caeruloplasmin mRNA levels were reduced in the two patients with Wilson's disease and also in a patient with fulminant hepatic failure. It remains to be confirmed if the reduction of caeruloplasmin mRNA is specific for Wilson's disease. Levels of mRNAs for copper zinc superoxide dismutase and metallothionein were variable and not related to liver copper.

Topics: Blotting, Northern; Blotting, Western; Carrier Proteins; Cell Fractionation; Centrifugation; Ceruloplasmin; Chromatography, Gel; Copper; Electrophoresis, Polyacrylamide Gel; Gene Expression; Hepatolenticular Degeneration; Humans; Liver; Metallothionein; RNA, Messenger; Superoxide Dismutase

Oral zinc therapy is effective in controlling copper balance in patients with Wilson's disease and blocks the intestinal absorption of copper, as demonstrated by uptake of copper 64 and copper balance measurements. In this study, 64Cu uptake measurements were concomitantly carried out with intestinal biopsies to investigate the relationship of reduced copper absorption to the levels of intestinal metallothionein in patients with Wilson's disease at different stages of zinc therapy. A pronounced increase in intestinal metallothionein levels and a sharp drop in 64Cu absorption were found 4 to 5 days after the initiation of zinc treatment. Conversely, metallothionein levels decreased and 64Cu uptake increased on the discontinuation of zinc therapy. The data indicate that 64Cu absorption varies as a function of intestinal metallothionein level. Intestinal metallothionein levels were found to correlate linearly with urinary zinc levels, which reflect body zinc status. These findings support our hypothesis that intestinal metallothionein induction mediates decreased copper absorption observed during zinc therapy. The suppressive effect of zinc on copper absorption appears to have a half-life of about 11 days.

Topics: Adult; Copper Radioisotopes; Female; Hepatolenticular Degeneration; Humans; Intestinal Absorption; Intestinal Mucosa; Male; Metallothionein; Zinc

D-penicillamine does not remove copper from metallothionein, but it has been suggested that it may increase hepatic metallothionein levels. D-penicillamine was shown to increase rat hepatic metallothionein levels; however, the effect was dependent on an interaction with copper. The drug accelerated the excretion of exogenous copper but increased the amount retained on metallothionein. This interaction of penicillamine and copper also provoked changes in the distribution of zinc and in particular an increase in the heat-stable cytosol zinc fraction. In contrast, thiomolybdates were much more effective in eliminating exogenous copper and even removed copper that was already bound to metallothionein; thus, the copper level in the heat-stable cytosol fraction decreased. The observations support the view that patients with Wilson's disease may not be truly "decoppered" but that treatment with d-penicillamine is effective because the accumulated copper in the liver is bound in a nontoxic form by the increased metallothionein. The results explain why cessation of treatment is dangerous. The results may also partially explain the effectiveness of D-penicillamine copper chelates as antiinflammatory drugs.

Topics: Animals; Arthritis; Copper; Cytosol; Hepatolenticular Degeneration; Humans; Injections, Intramuscular; Liver; Male; Metallothionein; Methionine; Molybdenum; Organometallic Compounds; Penicillamine; Rats; Rats, Inbred Strains; Reference Values; Zinc

We studied the Cu-MT present in the hepatic cytosol obtained from 7 patients suffering from conditions associated with hepatic Cu overload (Wilson's disease, biliary atresia, familial cholestatic cirrhosis). Since chromatographic methods appropriate for the isolation of Zn- and Cd-MT were unsuitable for Cu-MT, we developed an indirect procedure for the estimation and resolution of the latter. This procedure involved the preparation of apo-MT and its reconstitution to holo-MT with Zn or Cd. Three predominant isoforms of MT were present in all specimens. Our results indicate that at most 36 +/- 5% of the Cu present in the 10 kDa fraction of cytosol is bound to MT in the liver of patients with hepatic copper overload.

Topics: Adolescent; Adult; Biliary Atresia; Child; Child, Preschool; Copper; Cytosol; Female; Hepatolenticular Degeneration; Humans; Liver; Liver Cirrhosis, Biliary; Male; Metallothionein

The synthesis of radiolabeled metallothionein was induced in rats in vivo by the injection of CuSO4 and [35S]-cysteine. Treatment of "cold" rat liver cytosol "spiked" with purified [35S] metallothionein with Penicillamine and Trientine showed that even at relatively high concentrations (up to 50 mg/g liver, wet weight), these compounds had no effect on the copper peak or the position of the [35S] label in the cytosol eluate after Sephadex G-75 gel filtration. By contrast, incubation of the "spiked" liver cytosol with Trithiomolybdate, even at relatively low concentrations (0.5 mg/g liver, wet weight), resulted in a transfer of metallothionein copper to high molecular weight protein fractions; the position of the [35S] apoprotein was unaffected. This copper "stripping" effect on metallothionein supports clinical and other evidence that thiomolybdates have a genuine decoppering effect in vivo whereas Penicillamine and Trientine have another mode of action and indicates that thiomolybdates might provide a more rational alternate therapy for Wilson's disease patients.

Topics: Animals; Copper; Cytosol; Hepatolenticular Degeneration; Liver; Male; Metallothionein; Molybdenum; Penicillamine; Rats; Rats, Inbred Strains; Sulfur Radioisotopes; Trientine

Slightly higher levels of copper were incorporated into the liver in copper-nitrilotriacetic acid (Cu-NTA)-treated mice than in CuSO4-treated mice. There was no difference in the distribution of Cu in hepatic subfractions between the two groups. In the cytosol fraction, however, metallothionein (MT) was significantly decreased in the Cu-NTA-treated mice. Excretion of Cu from liver to bile and blood was not changed in the two groups. The poor induction of MT by Cu-NTA supports the possibility that the compound is more harmful than CuSO4.

Topics: Animals; Copper; Free Radicals; Hepatolenticular Degeneration; Liver; Male; Metallothionein; Mice; Mice, Inbred ICR; Nitrilotriacetic Acid

A rapid and sensitive method for determining Cu-containing metallothionein (MT) is described. The main features of this Cd-saturation assay are: high-molecular-weight Cd-binding compounds are denatured with acetonitrile (50% final concentration), Cu bound to MT is removed with ammonium tetrathiomolybdate, excessive tetrathiomolybdate and its Cu complexes are removed with DEAE-Sephacel, apothionein is saturated with Cd, and excessive Cd is bound to Chelex 100. The thiomolybdate assay is capable of reliably detecting 14 ng MT and thus is particularly suitable for measuring MT in small tissue samples (e.g., biopsies), in extrahepatic tissues, and in cultured cells. Moreover, the combination of the thiomolybdate assay with the recently developed Cd-Chelex assay also makes it possible to determine the portion of MT which binds Cu (Cu load of MT), provided that the amount of non-Cu-thionein exceeds 100 ng, the detection limit of the Cd-Chelex assay.

Topics: Animals; Cadmium; Cadmium Radioisotopes; Cells, Cultured; Chemistry Techniques, Analytical; Child; Child, Preschool; Chromatography, Gel; Copper; Cysteine; Ethanolamines; Fibroblasts; Glutathione; Hepatolenticular Degeneration; Humans; Male; Metallothionein; Molybdenum; Rats; Rats, Inbred Strains

Topics: Absorption; Diet; Female; Hepatolenticular Degeneration; Homeostasis; Humans; Intestinal Mucosa; Male; Metallothionein; Pancreas; Phytic Acid; Zinc

We report the first use of an emission probe based on the Cu(I)-thiolate chromophore, for the direct observation of copper metallothionein located in samples of rat liver. Elevated synthesis of Cu-MT in the rat liver was induced by subcutaneous injections of a series of aqueous CuCl2 solutions containing increasing amounts of Cu(II). Luminescence intensity in the 600 nm region, detected from frozen solutions of Cu-MT and from slices of the liver frozen at 77 K, following excitation in the 300 nm region, was dependent on the concentration of the Cu(II) used in the inducing solution. No such luminescence intensity was found for control samples obtained from the livers of rats not exposed to copper salts. It is suggested that this new method will allow direct visualization of Cu-MT in tissue where genetic disorders impare copper metabolism.

Topics: Animals; Copper; Hepatolenticular Degeneration; Humans; Liver; Luminescence; Metallothionein; Rats; Spectrum Analysis

Topics: Animals; Hepatolenticular Degeneration; Humans; Liver; Metallothionein; Zinc

Eleven patients with newly diagnosed Wilson's disease were treated with zinc acetate as their sole anticopper therapy. Treatment duration was 8 to 37 months. Three of the patients had symptoms; in eight who were presymptomatic, diagnosis was made because of affected siblings who had symptoms. All patients did well clinically. Copper absorption was suppressed, as reflected by blockade of absorption of orally administered copper 64. Values for 24-hour urine copper and nonceruloplasmin plasma copper (freely available copper) were reduced. Values for liver-derived serum enzymes were also generally reduced in patients who had pretreatment elevations. Percutaneous liver biopsies were done initially and repeated in seven of the patients after 12 to 35 months of zinc therapy. In five of these patients a second biopsy specimen showed higher levels of copper than the first. In three of these five a third biopsy 6 to 23 months after the second revealed liver copper values that either had returned to the baseline value or were lower. One patient's initial biopsy specimen showed active inflammation, which subsided with therapy. All of the biopsies revealed histologic scarring typical of cirrhosis, and this did not appear to change over the course of therapy. We conclude that hepatic copper may increase temporarily during early zinc therapy but that the accumulated copper is sequestered in a nontoxic form. On the basis of animal studies we postulate that this sequestered copper is primarily bound to the high levels of hepatic metallothionein induced by zinc. Zinc appears to be a reasonable option for the initial treatment of patients with Wilson's disease, particularly those with presymptomatic disease.

Topics: Acetates; Acetic Acid; Alanine Transaminase; Aspartate Aminotransferases; Biopsy, Needle; Copper; Follow-Up Studies; Hepatolenticular Degeneration; Humans; Liver; Metallothionein; Time Factors; Zinc

Patients with Wilson's disease often have a further increase in hepatic copper when given zinc as an initial treatment, although there is no associated clinical deterioration. To better understand this situation an animal model was developed in which copper-loaded rats are treated with zinc administered subcutaneously. In the presence of equal amounts of copper loading in liver, control rats show hepatic damage but zinc-treated rats do not. Zinc-treated rats have much higher levels of hepatic metallothionein. Gel filtration studies reveal that much of the hepatic copper in zinc-treated rats is in this metallothionein fraction, whereas the copper in control animals is primarily associated with fractions of high or low molecular weight. Subcutaneous zinc therapy also induces intestinal, but not brain, metallothionein. We interpret these findings to indicate that zinc therapy protects against copper toxicity in liver by induction of hepatic metallothionein, which sequesters copper in a nontoxic form.

Topics: Alanine Transaminase; Animals; Chromatography, Gel; Copper; Cytosol; Delayed-Action Preparations; Diet; Hepatolenticular Degeneration; Liver; Liver Diseases; Male; Metallothionein; Rats; Zinc

Topics: Child; Copper; Hepatolenticular Degeneration; Humans; Liver Cirrhosis; Metallothionein; Protein Binding

In certain pathological and experimental conditions associated with hepatic copper overload, an important portion of the excess metal is bound to a copper-thionein and sequestered in hepatocellular lysosomes. The localization can be demonstrated visually by using histochemical and immunocytochemical stains and by extraction of the Cu-protein from particulate fractions of liver homogenates. The livers of Bedlington terriers affected by an inherited defect resulting in the accumulation of large quantities of copper display hepatocellular lysosomes which appear as dense, insoluble, copper-rich granules. Purification and solubilization of the fraction containing these granules yields a copper-thionein with little zinc, which displays homology with other known metallothioneins. Although the primary genetic defect which underlies the pathogenesis of this form of hepatic copper overload is still unknown, circumstantial evidence suggests that sequestration of the protein by lysosomes may be temporarily cytoprotective.

Topics: Aging; Animals; Copper; Disease Models, Animal; Dogs; Hepatolenticular Degeneration; Liver; Lysosomes; Metal Metabolism, Inborn Errors; Metallothionein; Microscopy, Electron

Wilson's disease is a rare inherited disorder of copper (Cu) metabolism characterized by the deposition of Cu in the liver, brain, and cornea. The levels of metallothionein (MT), Cu, and zinc (Zn) in the livers of two Wilson's disease patients were analyzed in this study. About 50-fold increase in the Cu levels above normal controls was observed in both patients (160 and 298 micrograms/g of wet tissue). About 73% of subcellular Cu was present in the cytoplasmic fraction and most of it was in association with MT. Analysis of hepatic MT levels showed a 3-fold increase (863 micrograms/g of wet tissue) over control human levels (321 micrograms/g of wet tissue). The two forms of MT (MT-I and MT-II) were isolated from one liver sample. Both forms contained high amounts of Cu (11 to 12 g atoms/mole), indicating saturation of MT which had only 2 to 3 g atoms of zinc. The distribution of MT in the hepatocytes was investigated using an immunohistochemical method. In tissue sections with minimal tissue damage, there was intense cytoplasmic staining for MT in hepatocytes whereas both nuclear and cytoplasmic staining was found in tissue sections with extensive necrosis and fibrosis. These results suggest that MT is the major hepatic Cu-binding protein in Wilson's disease, that it is present in a form saturated with Cu, and that only in degenerating hepatocytes is it found in the nucleus as well as the cytoplasm.

Topics: Adult; Child; Copper; Cytoplasm; Hepatolenticular Degeneration; Humans; Immunoenzyme Techniques; Liver; Male; Metallothionein; Zinc

Cultured skin fibroblasts from patients with Menkes disease and Wilson disease were analyzed as to their sensitivities to copper and cadmium by means of a colony-forming ability and cell growth study. All the Menkes strains exhibited about 3-fold higher levels of resistance to cadmium, whereas the cytotoxicity of copper did not differ among the Menkes, Wilson and normal fibroblast strains. The resistance to cadmium of Menkes skin fibroblasts may provide a diagnostic marker of Menkes disease and useful or valuable model for the understanding of detoxification system against heavy metals.

Topics: Brain Diseases, Metabolic; Cadmium; Cadmium Chloride; Cell Division; Colony-Forming Units Assay; Copper; Drug Resistance; Fibroblasts; Hepatolenticular Degeneration; Humans; Menkes Kinky Hair Syndrome; Metallothionein; Osmolar Concentration; Skin

Topics: Angiogenesis Inducing Agents; Animals; Ceruloplasmin; Copper; Hepatolenticular Degeneration; Humans; Menkes Kinky Hair Syndrome; Metallothionein; Mice; Neoplasms; Neovascularization, Pathologic

Cultured fibroblasts deriving from Wilson disease patients were compared with the control ones in respect of copper accumulation and low molecular weight copper binding protein (metallothionein) properties. No evidence was obtained that metallothionein abnormality could be a primary cause of copper metabolism disturbances in Wilson disease. The determination of radioactivity, present in serum low molecular weight fraction 24 hours after intravenous injection of 64Cu, has been suggested as an additional tool in Wilson disease diagnosis in doubtful cases.

Topics: Copper; Fibroblasts; Hepatolenticular Degeneration; Humans; Metallothionein; Molecular Weight; Skin

Copper concentration, intracellular copper distribution, and inducibility of metallothionein-like metal-binding protein (MLP) by copper or cadmium addition to culture medium were compared among three types of skin fibroblasts derived from patients with Menkes' disease and Wilson's disease, both exhibiting genetic defects of copper metabolism, and from normal subjects (control). Skin fibroblasts were cultivated in Dulbecco's modified Eagle's medium supplemented with 10% fetal calf serum and antibiotics in 5% CO2 at 37 degrees C. Cells were harvested with rubber-policeman, washed twice with phosphate-buffered saline, pH 7.2, suspended in deionized water, and homogenized. The homogenate from each cell type was used to determine the concentration of copper by atomic absorption spectrophotometry employing graphite-rod atomizer after lyophilization, ashing in HNO3, and coprecipitation with zirconium. Intracellular copper concentration was elevated in Menkes' cells (420 ng Cu/mg of protein) and Wilson's cells (217 ng Cu/mg of protein) than in control cells (90.0 ng Cu/mg of protein), although one of four Wilson's strains showed normal copper level (70.5 ng Cu/mg of protein). Cytosol copper concentration was 5.8-fold higher in Menkes' cells but only 1.3-fold in Wilson's cells than in control cells, and cytosol copper accounted for only 35% of total intracellular copper in Wilson's cells as compared with 68% and 52% in Menkes' and control cells, respectively. These suggest that accumulated copper in each cell type is differently distributed within cells; in Menkes' cells exclusively into cytosol, but in Wilson's cells into particulates rather than cytosol. Elution profiles from Sephadex G-75 columns indicated that most of copper had bound to MLP in Menkes' cells, though no Cu-MLP was detectable in Wilson's or control cells under these experimental conditions.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Adolescent; Adult; Brain Diseases, Metabolic; Carrier Proteins; Cell Line; Cells, Cultured; Child; Chromatography, Gel; Copper; Female; Fibroblasts; Hepatolenticular Degeneration; Humans; Infant; Male; Menkes Kinky Hair Syndrome; Metallothionein; Skin

Copper is an essential dietary component, being the coenzyme of many enzymes with oxidase activity, e.g. ceruloplasmin, superoxide dismutase, monoamine oxidase, etc. The metabolism of copper is complex and imperfectly known. Active transport of copper through the intestinal epithelial cells involves metallothionein, a protein rich in sulfhydryl groups which also binds the copper in excess and probably prevents absorption in toxic amounts. In hepatocytes a metallothionein facilitates absorption by a similar mechanism and regulates copper distribution in the liver: incorporation in an apoceruloplasmin, storage and synthesis of copper-dependent enzymes. Metallothioneins and ceruloplasmin are essential to adequate copper homeostasis. Apart from genetic disorders, diseases involving copper usually result from hypercupraemia of varied origin. Wilson's disease and Menkes' disease, although clinically and pathogenetically different, are both marked by low ceruloplasmin and copper serum levels. The excessive liver retention of copper in Wilson's disease might be due to increased avidity of hepatic metallothioneins for copper and decreased biliary excretion through lysosomal dysfunction. Menkes' disease might be due to low avidity of intestinal and hepatic metallothioneins for copper. The basic biochemical defect responsible for these two hereditary conditions has not yet been fully elucidated.

Topics: Adolescent; Adult; Ceruloplasmin; Child; Copper; Hepatolenticular Degeneration; Humans; Infections; Inflammation; Intestinal Absorption; Liver; Menkes Kinky Hair Syndrome; Metabolic Diseases; Metallothionein

Topics: Copper; Hepatolenticular Degeneration; Humans; Liver; Metalloproteins; Metallothionein