Zinc and tetrathiomolybdate for the treatment of Wilson's disease and the potential efficacy of anticopper therapy in a wide variety of diseases

Wilson's disease, an autosomal recessive disease of copper accumulation and copper toxicity primarily in the liver and brain, has been the engine that has driven the development of anticopper drugs. Here we first briefly review Wilson's disease, then review the four anticopper drugs used to treat Wilson's disease. We then discuss the results of therapy with anticopper drugs in Wilson's disease, with special emphasis on the newer and better drugs, zinc and tetrathiomolybdate. We then discuss new areas of anticopper therapy, lowering copper availability with tetrathiomolybdate as a therapy in fibrotic, inflammatory, and autoimmune disorders. Many of the cytokines which promote these disorders are copper dependent, and lowering copper availability lessens the activity of these cytokines, favorably influencing a variety of disease processes. Copper in the blood can be thought of as in two pools. One pool is covalently bound in ceruloplasmin, a protein containing six coppers, synthesized by the liver and secreted into the blood. Ceruloplasmin copper accounts for almost 85 to 90% of the blood copper in normal people. This copper is tightly bound and not readily available for cellular uptake and copper toxicity. The other 10-15% of copper is more loosely bound to albumin and other small molecules in the blood, and is readily and freely available to cells and available to cause copper toxicity, if this pool of copper is increased. We call this latter pool of copper "free" copper because of its more ready availability. However, it should be understood that it is not completely free, always being bound to albumin and other molecules. It is this pool of free copper that is greatly expanded in untreated Wilson's patients undergoing copper toxicity.     

Tetrathiomolybdate anticopper therapy for Wilson's disease inhibits angiogenesis,fibrosis and inflammation

The need for agents to lower body copper in Wilson's disease, a disease which results from copper toxicity has been the driving force for the development of the effective anticopper drugs penicillamine, trientine, zinc, and now tetrathiomolybdate (TM). Because of its rapid action, potency, and safety, TM is proving to be a very effective drug for initial treatment of acutely ill Wilson's disease patients. Beyond this, TM has antiangiogenic effects, because many proangiogenic cytokines require normal levels of copper. This has led to use of TM in cancer, where it is generally effective in animal tumor models, and has shown efficacy in preliminary clinical studies. Most recently, it has been found that TM has antifibrotic and antiinflammatory effects through inhibition of profibrotic and proinflammatory cytokines.     

Comparative efficacy of several potential treatments for copper mobilization in copper-overloaded rats

d-Penicillamine (DPA) is effective in the treatment of Wilson’s disease, whereas zinc salts are also used as a therapy for this disorder of copper transport. Recently, it has been shown that the copper chelators 1,4,7,11-tetraazaundecane tetrahydrochloride (TAUD) and tetraethylenepentamine pentahydrochloride (TETREN) could be useful for copper mobilization in rats. Because these agents could be potential clinical alternatives to DPA for patients with Wilson’s disease who are intolerant to this drug, we examined whether oral administration of TAUD and TETREN could be effective in mobilizing copper in experimental copper-overloaded rats. The efficacy of a combined administration of zinc and DPA, TAUD, or TETREN was also assessed. Rats were copper loaded with 0.125% copper acetate in water for 12 wk. After this period, DPA, TAUD, and TETREN were administered by gavage at 0.67 mmol/kg/d for 5 d, and zinc was given at 2.5 mg Zn/kg/d. Twelve weeks of copper loading resulted in a 32-fold increase in total hepatic copper. TETREN was the most effective chelator in increasing the urinary excretion of copper. However, it did not reduce significantly the hepatic copper levels. In turn, combined administration of zinc and chelating agents significantly reduced the amount of copper found in the feces. Although TAUD and TETREN showed a similar or higher efficacy to DPA in mobilizing copper, concurrent treatment of chelating agents and zinc salts should be discarded according to the current results.     

Recognition, diagnosis, and management of Wilson's disease

Wilson's disease is a relatively rare inherited disorder of copper accumulation and toxicity, caused by a defect in an enzyme that is part of the pathway of biliary excretion of excess copper. Clinically, patients usually present as older children or young adults with hepatic, neurologic, or psychiatric manifestations, or some combination of these. Wilson's disease is unusual among genetic diseases in that it can be very effectively treated. The prevention of severe permanent damage depends upon early recognition and diagnosis by the physician, followed by appropriate anticopper treatment. Anticopper treatments have evolved considerably since the days when the only drug available was penicillamine. Zinc is now the recommended therapy for long-term management of the disease.     

Endocrine symptoms as the initial manifestation of Wilson's disease

Wilson's disease is a rare genetic disorder of copper metabolism. The difference in copper tissue accumulation is responsible for the various clinical manifestations of this disorder. If left untreated, Wilson's disease progresses to hepatic failure, severe neurological disability, and even death. Due to the complex clinical picture of Wilson's disease, its diagnosis relies on a high index of suspicion. In our paper, we present endocrine symptoms suggesting the presence of insulinoma and hyperprolactinemia as the initial clinical manifestation of Wilson's disease in a young female. Zinc acetate treatment resulted in the disappearance of hypoglycemia, galactorrhea, and menstrual abnormalities.     

Function and Regulation of the Mammalian Copper-transporting ATPases: Insights from Biochemical and Cell Biological Approaches

Copper is an essential trace element that plays a very important role in cell physiology. In humans, disruption of normal copper homeostasis leads to severe disorders, such as Menkes disease and Wilson's disease. Recent genetic, cell biological, and biochemical studies have begun to dissect the molecular mechanisms involved in transmembrane transport and intracellular distribution of copper in mammalian cells. In this review, we summarize the advances that have been made in understanding of structure, function, and regulation of the key human copper transporters, the Menkes disease and Wilson's disease proteins.     

Effects of iron(II) salts and iron(III) complexes on trace element status in children with iron-deficiency anemia

Iron-deficiency anemia (IDA) is the most common nutritional deficiency in childhood throughout the world. Although it has been shown that IRA is associated with elevated plasma copper and depleted zinc levels in children, there are conflicting results on the effect of iron supplementation on the absorption of these elements. The aim of this study was to investigate the effects of ferrous and ferric iron supplementation on the trace element status in children (n=25, aged 8-168 mo) with IDA. Fourteen of them were treated with ferric hydroxide-polymaltose complex (Ferrum, Vifor, Switzerland) (6 mg/d in the first 3 mo for initial therapy and 3 mg/kg for 3 mo as maintenance); the others were treated with a ferrous sulfate complex (FerroSanol, Schwarz, Germany) (6 mg/d in the first 3 mo for initial therapy and 3 mg/kg for 3 mo as maintenance). Plasma copper, zinc, and ceruloplasmin levels as well as hematological parameters were determined at baseline and the first, third, and sixth month of the treatment period. The hemoglobin and iron levels of patients in both groups were higher in the first and sixth months compared to baseline. Although the ceruloplasmin levels were depleted (48.9 mg/dL vs 41.4 mg/dL, p=0.035) during ferrous iron treatment, the copper and zinc levels remained unchanged. On the other hand, ferric iron supplementation led to an increase in zinc levels in the sixth month of treatment (0.77 mg/L vs 1.0 mg/L, p=0.021). The plasma copper levels were lower in the ferrous iron-treated group at the end of the first month of treatment than in the ferric irontreated group (1.06 mg/L vs 1.29 mg/L, p=0.008). In conclusion, our data showed that copper and ceruloplasmin metabolisms were affected by ferrous iron supplementation, whereas ferric iron kept them to normal levels of zinc, possibly by affecting their absorption. We conclude that the copper and zinc status of patients with IDA should be taken into consideration before and after iron therapy.     

Copper excess, zinc deficiency, and cognition loss in Alzheimer's disease

In this special issue about biofactors causing cognitive impairment, we present evidence for and discuss two such biofactors. One is excess copper, causing neuronal toxicity. The other is zinc deficiency, causing neuronal damage. We present evidence that Alzheimer's disease (AD) has become an epidemic in developed, but not undeveloped, countries and that the epidemic is a new disease phenomenon, beginning in the early 1900s and exploding in the last 50 years. This leads to the conclusion that something in the developed environment is a major risk factor for AD. We hypothesize that the factor is inorganic copper, leached from the copper plumbing, the use of which coincides with the AD epidemic. We present a web of evidence supporting this hypothesis. Regarding zinc, we have shown that patients with AD are zinc deficient when compared with age-matched controls. Zinc has critical functions in the brain, and lack of zinc can cause neuronal death. A nonblinded study about 20 years ago showed considerable improvement in AD with zinc therapy, and a mouse AD model study also showed significant cognitive benefit from zinc supplementation. In a small blinded study we carried out, post hoc analysis revealed that 6 months of zinc therapy resulted in significant benefit relative to placebo controls in two cognitive measuring systems. These two factors may be linked in that zinc therapy significantly reduced free copper levels. Thus, zinc may act by lowering copper toxicity or by direct benefit on neuronal health, or both.     

Extrahepatic tissue copper concentrations in white perch with hepatic copper storage

Hepatic copper storage in man (Wilson's disease), Bedtington and West Highland white terriers, and white perch ( Morone americana ) is characterized by the progressive accumulation of copper in hepatic lysosomes bound to cytoprotective metallothionein. In man, saturation of the liver storage capacity results in the distribution of copper to extrahepatic tissues with multiple organ system dysfunction. To determine if extrahepatic tissue copper concentrations also increase in white perch, copper and zinc levels in liver, brain, heart, gills, serum, and bile were determined by atomic absorption spectrophotometry and compared to striped bass ( Morone saxatilis ). Results showed that brain copper concentrations in. white perch were elevated and significantly correlated with liver copper. Bile and serum copper also increased significantly with liver copper. Copper levels in heart and gill tissues were low. Liver zinc was increased in white perch but not to the same magnitude as copper, and was correlated significantly with liver copper; possibly a non-specific secondary increase related to an overall increase in hepatic metallothionein. Histochemical staining of liver with rubeimc acid for copper was proportional to copper concentrations, and clusters of positive mononuclear cells were also seen in brain and spleen. Foci of macrophages in spleen were also intensely positive with Perl's iron stain which may have been indicative of haemolysis. The patterns of copper distribution seen in white perch present a useful comparative model to study alterations in copper metabolism.     

Copper and zinc metabolism with solid tumor growth

The variation in copper and zinc metabolism with tumor growth appears to relate directly to progression or regression of the disease. Historically, elevations in serum copper have been used as clinical indicators in hematological neoplasms since the early 1960s. More recently, we have monitored breast, colo-rectal, and lung cancer patients for a six-month period through courses of cytotoxic chemotherapy to determine copper and zinc changes with tumor growth. Groups were divided into responders and nonresponders blind to their serum copper and zinc levels. Trends in elevated serum copper with active disease have shown similar trends in decreasing values with effective therapy, but normalization was at a slower rate. Serum zinc levels in the same patients were markedly below normal and did not increase in the study period. The clinical significance or elevated serum copper and depressed serum zinc is discussed and the potential relationship between the two elements is explored. A solid tumor-bearing rat model, mammary adenocarcinoma R 3230 AC, has detailed more of the changes in copper and zinc metabolism with solid tumor growth. Serum copper and zinc varied with tumor mass, as in clinical studies. Liver values of the two essential metals did not change significantly, but liver-related copper-containing enzymes showed marked variations. Ceruloplasmin in serum increased with increasing tumor mass, as would be expected with the increased serum copper levels. Cytochrome c oxidase activity in liver homogenates from tumor-bearing animals was significantly depressed.     

Predicting genotypes at loci for autosomal recessive disorders using linked genetic markers: application to Wilson's disease

Summary Recently, the Wilson's disease locus (WND) has been mapped to the long arm of chromosome 13. We have analyzed segregation of serveral chromosome 13 markers flanking the WND locus and used multipoint linkage analysis to determine the most likely WND genotype of each of 57 unaffected individuals in 5 Wilson's disease families. Approximately 46% of these could be classified as carrier (heterozygote), homozygous normal, or homozygous affected (not yet symptomatic) with a probability of at least 90%, while 77% could be classified with a probability of at least 80%. Our results demonstrate that even though there is a significant decrease on average in serum copper concentration in Wilson's disease heterozygotes compared to normal homozygotes, other sources of variation in serum copper concentration are much greater and preclude use of serum copper to detect heterozygotes for Wilson's disease. Subsequent analyses showed that a familial component, independent of WND genotype, is the major factor accounting for variation in ceruloplasmin levels among unaffected individuals; age is another factor accounting for more variation in copper levels among unaffected individuals than WND genotype.     

Human copper-transporting ATPase ATP7B (the Wilson's disease protein): biochemical properties and regulation

Wilson's disease protein (WNDP) is a product of a gene ATP7B that is mutated in patients with Wilson's disease, a severe genetic disorder with hepatic and neurological manifestations caused by accumulation of copper in the liver and brain. In a cell, WNDP transports copper across various cell membranes using energy of ATP-hydrolysis. Copper regulates WNDP at several levels, modulating its catalytic activity, posttranslational modification, and intracellular localization. This review summarizes recent studies on enzymatic function and copper-dependent regulation of WNDP. Specifically, we describe the molecular architecture and major biochemical properties of WNDP, discuss advantages of the recently developed functional expression of WNDP in insect cells, and summarize the results of the ligand-binding studies and molecular modeling experiments for the ATP-binding domain of WNDP. In addition, we speculate on how copper binding may regulate the activity and intracellular distribution of WNDP, and what role the human copper chaperone Atox1 may play in these processes.     

The Correlation of Serum Trace Elements and Heavy Metals with Carotid Artery Atherosclerosis in Maintenance Hemodialysis Patients

Changes in essential trace elements and heavy metals may affect the atherosclerotic state of patients on maintenance hemodialysis (HD). The aim of the study was to evaluate the relation between the serum levels of some trace elements and heavy metals (iron, zinc, manganese, copper, magnesium, cobalt, cadmium, lead, and copper/zinc ratio) and carotid artery intima-media thickness (CIMT) in HD patients. Fifty chronic HD patients without known atherosclerotic disease and 48 age- and sex-matched healthy individuals were included in the study. The serum levels of trace elements (iron, zinc, manganese, copper, and magnesium) and heavy metals (cobalt, cadmium, and lead) were measured by Atomic Adsorption Spectrophotometer (UNICAM-929). CIMT was assessed by carotid artery ultrasonography. The serum levels of iron, zinc, and manganese were lower; levels of copper, magnesium, cobalt, cadmium, lead, and copper/zinc ratio were higher in HD patients compared to controls. CIMT in HD patients were higher than the control group (0.64?±?0.11 vs 0.42?±?0.05, p?相似文献   

Copper chelation with tetrathiomolybdate suppresses adjuvant-induced arthritis and inflammation-associated cachexia in rats

Tetrathiomolybdate (TM), a drug developed for Wilson's disease, produces an anti-angiogenic and anti-inflammatory effect by reducing systemic copper levels. TM therapy has proved effective in inhibiting the growth of tumors in animal tumor models and in cancer patients. We have hypothesized that TM may be used for the therapy of rheumatoid arthritis and have examined the efficacy of TM on adjuvant-induced arthritis in the rat, which is a model of acute inflammatory arthritis and inflammatory cachexia. TM delayed the onset of and suppressed the severity of clinical arthritis on both paw volume and the arthritis score. Histological examination demonstrated that TM significantly reduces the synovial hyperplasia and inflammatory cell invasion in joint tissues. Interestingly, TM can inhibit the expression of vascular endothelial growth factor in serum synovial tissues, especially in endothelial cells and macrophages. Moreover, the extent of pannus formation, which leads to bone destruction, is correlated with the content of vascular endothelial growth factor in the serum. There was no mortality in TM-treated rat abnormalities. TM also suppressed inflammatory cachexia. We suggest that copper deficiency induced by TM is a potent approach both to inhibit the progression of rheumatoid arthritis with minimal adverse effects and to improve the well-being of rheumatoid arthritis patients.     

Quercetin cumulatively enhances copper induction of metallothionein in intestinal cells

Wilson’s disease, a genetic copper-overload condition, is currently treated with zinc because of the ability of zinc to induce metallothionein. We are interested in nonmetal chemicals that may alter intestinal copper metabolism and thus help to alleviate copper toxicity. Previously, we have shown that quercetin, a dietary flavonoid, can chelate copper. This study further examined the interaction of quercetin and copper in intestinal epithelial cells. We found that quercetin enhanced metallothoinein induction by copper and the effect was dose dependent. Quercetin also exerted a cumulative effect after repeated exposure. Repeated low-dose treatment (3–10 μM) of cells with quercetin can lead to the same effect on metallothoinein as one higher concentration treatment (100 μM). This property of quercetin is distinct from its chemical interaction with copper, but both can contribute to a reduction of copper toxicity. Among other flavonoids tested, two other copper chelators, catechin and rutin, did not increase copper induction of metallothionein, whereas genistein, an isoflavone that does not interact with copper chemically, increased copper induction of metallothionein. The effect of quercetin on copper metabolism is unique. Quercetin decreased zinc-stimulated metallothionein expression and had no effect on the cadmium induction of metallothionein. The clinical application of our observation needs to be explored.     

Classification and prognostic value of serum copper/zinc ratio in hodgkin’s disease

The serum copper and zinc levels were determined by atomic absorption spectrometry in 135 Hodgkin's disease (HD) patients and in 100 healthy controls. These values were used to explore the application value of the serum copper/zinc ratio in the histologic classification and prognosis in this illness. The resuls show that serum copper and the copper/zinc ratio were higher and the serum zinc level was lower in the HD patients when compared to the healthy individuals (p < 0.01, 0.001, and 0.01, respectively). The serum copper and copper/zinc ratio were significantly higher in the lymphocyte-depleted type of HD than in the patients with the mixed-cellular type of HD. These values were also higher and the serum zinc was lower in the patients with mixed-cellular HD when compared to the nodular-sclerosis and the lymphocyte-predominant types of the disease (p < 0.01 and 0.001, respectively). It was also shown that as the disease progresses, the serum copper level and copper/zinc ratio rises with the concomitant decrease of the corresponding serum zinc level. These trends are reversed in cases where the disease is in remission. Both the serum copper level and the copper/zinc ratio were strongly correlated to histopathological changes, clinical stage, and prognosis of Hodgkin's disease.     

Estimation of serum zinc and copper in children with acute diarrhea

Diarrhea is, in reality, as much a nutritional disease as one of fluid and electrolyte loss. Children who die from diarrhea, despite good management of dehydration, are usually malnourished and often severely so. In this study, we determined the serum levels of zinc and copper before and after standard oral rehydration solution (ORS) therapy in children with acute diarrhea and correlated it with diarrheal duration and severity. One hundred ten children suffering from acute diarrhea were included. Serum zinc and copper levels of these children were estimated at the time of enrollment and after treatment with standard ORS therapy. This study shows that children suffering from acute diarrhea show a statistically significant decrease of 13.1% and 12.8% in serum zinc and copper concentrations, respectively, compared to normal. These levels further decrease by 22.6% and 22.4%, respectively, after treatment with standard ORS therapy. Our study shows that children with the lower plasma zinc and copper levels suffered with more severe and longer duration of diarrhea. Zinc and copper supplementation could be added to standard ORS therapy for the reduction in morbidity and mortality associated with acute diarrhea in children.     

Teratogenic risk during treatment of Wilson disease

Untreated Wilson's disease usually causes infertility or abortion, as a result of increased intrauterine copper level. Therefore, a chelation treatment is necessary during the whole pregnancy. The most used is D-Penicillamine whose teratogenic risks such as cutis laxa, dermatopathy or complex mesenchyme abnormalities are paradoxically rare in the new borns of treated Wilson's disease mothers, perhaps owing to hypercupremia that protects the foetus from excessive copper deficiency. Yet, it's wise to reduce chelation treatment about a quarter fold and to add 50 mg vitamin B6 weekly as we did in our case whose child was born normal.     

Acrodermatitis enteropathica

We report on the successful use of repeated hair analyses over three decades to monitor zinc and copper status in two siblings with Acrodermatitis enteropathica who were treated with oral zinc sulfate beginning in 1975. Furthermore, we report for the first time that analysis of zinc in hair over a 30-yr period allows for the identification of individuals who might be heterozygous carriers of this autosomal recessive disease and who, therefore, would be expected to have hair zinc levels intermediate between normal, healthy individuals and those with Acrodermatitis enteropathica. Zinc treatment of the two patients with Acrodermatitis enteropathica resulted in remission of the signs and symptoms of the disease within the first month of therapy. However, any short-term interruption (typically, 7-10 d) in oral zinc resulted in an almost immediate relapse, with the reappearance of the skin lesions. We also document the inverse relationship that exists between zinc and copper through analysis of these metals in the scalp hair from the two patients, thus providing a tool for ensuring adequate copper intake in patients taking relatively high doses of zinc over a long period.     

Copper specifically regulates intracellular phosphorylation of the Wilson's disease protein, a human copper-transporting ATPase

Copper is a trace element essential for normal cell homeostasis. The major physiological role of copper is to serve as a cofactor to a number of key metabolic enzymes. In humans, genetic defects of copper distribution, such as Wilson's disease, lead to severe pathologies, including neurodegeneration, liver lesions, and behavior abnormalities. Here, we demonstrate that, in addition to its role as a cofactor, copper can regulate important post-translational events such as protein phosphorylation. Specifically, in human cells copper modulates phosphorylation of a key copper transporter, the Wilson's disease protein (WNDP). Copper-induced phosphorylation of WNDP is rapid, specific, and reversible and correlates with the intracellular location of this copper transporter. WNDP is found to have at least two phosphorylation sites, a basal phosphorylation site and a site modified in response to increased copper concentration. Comparative analysis of WNDP, the WNDP pineal isoform, and WNDP C-terminal truncation mutants revealed that the basal phosphorylation site is located in the C-terminal Ser(796)-Tyr(1384) region of WNDP. The copper-induced phosphorylation appears to require the presence of the functional N-terminal domain of this protein. The novel physiological role of copper as a modulator of protein phosphorylation could be central to understanding how copper transport is regulated in mammalian cells.