Rediscovery of the susceptibility of G6PD deficient persons to methemoglobinemia from oxidant drugs, and to hemolysis from methylene blue.
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Enzyme Inhibitors↗
Biomedical subjects
George J Brewer
Publications and source records attributed to George J Brewer.
Tetrathiomolybdate is effective in a mouse model of arthritis.
OBJECTIVE: To test for protective effects of therapy with tetrathiomolybdate, a copper-lowering drug, against collagen-induced arthritis in mice. METHODS: Mice were injected with bovine collagen II, and limb joint swelling and erythema were scored. Tetrathiomolybdate treated mice received drug by oral gavage or in drinking water. Plasma ceruloplasmin was followed as a measure of body copper status, and maintained between 20 and 60% of baseline. Urine for isoprostane studies was collected in metabolic cages. At sacrifice, blood was collected for cytokine assays, and hind limbs fixed in formalin. RESULTS: Tetrathiomolybdate strongly protected against the collagen-induced arthritis as reflected in scores of swelling and erythema, and as seen histologically. Further, tetrathiomolybdate strongly protected against the increase in urine isoprostanes (a marker of oxidant damage) seen in collagen treated controls. The drug also protected against the increase in interleukin 2, interleukin 1beta, and tumor necrosis factor-a levels seen in collagen treated controls. CONCLUSION: Based on the positive results reported here, and the good safety profile of tetrathiomolybdate in human studies so far, a trial of tetrathiomolybdate in arthritis syndromes seems warranted.
Administration, Oral↗
XIAP Is a copper binding protein deregulated in Wilson's disease and other copper toxicosis disorders.
X-linked inhibitor of apoptosis (XIAP), known primarily for its caspase inhibitory properties, has recently been shown to interact with and regulate the levels of COMMD1, a protein associated with a form of canine copper toxicosis. Here, we describe a role for XIAP in copper metabolism. We find that XIAP levels are greatly reduced by intracellular copper accumulation in Wilson's disease and other copper toxicosis disorders and in cells cultured under high copper conditions. Elevated copper levels result in a profound, reversible conformational change in XIAP due to the direct binding of copper to XIAP, which accelerates its degradation and significantly decreases its ability to inhibit caspase-3. This results in a lowering of the apoptotic threshold, sensitizing the cell to apoptosis. These data provide an unsuspected link between copper homeostasis and the regulation of cell death through XIAP and may contribute to the pathophysiology of copper toxicosis disorders.
Apoptosis↗
Treatment of Wilson disease with ammonium tetrathiomolybdate: IV. Comparison of tetrathiomolybdate and trientine in a double-blind study of treatment of the neurologic presentation of Wilson disease.
OBJECTIVE: To compare tetrathiomolybdate and trientine in treating patients with the neurologic presentation of Wilson disease for the frequency of neurologic worsening, adverse effects, and degree of neurologic recovery. DESIGN: A randomized, double-blind, controlled, 2-arm study of 48 patients with the neurologic presentation of Wilson disease. Patients either received 500 mg of trientine hydrochloride 2 times per day or 20 mg of tetrathiomolybdate 3 times per day with meals and 20 mg 3 times per day between meals for 8 weeks. All patients received 50 mg of zinc 2 times per day. Patients were hospitalized for 8 weeks, with neurologic and speech function assessed weekly; discharged taking 50 mg of zinc 3 times per day, and returned annually for follow-up. SETTING: A university hospital referral setting. PATIENTS: Primarily newly diagnosed patients with Wilson disease presenting with neurologic symptoms who had not been treated longer than 4 weeks with an anticopper drug. INTERVENTION: Treatment with either trientine plus zinc or tetrathiomolybdate plus zinc. MAIN OUTCOME MEASURES: Neurologic function was assessed by semiquantitative neurologic and speech examinations. Drug adverse events were evaluated by blood cell counts and biochemical measures. RESULTS: Six of 23 patients in the trientine arm and 1 of 25 patients in the tetrathiomolybdate arm underwent neurologic deterioration (P<.05). Three patients receiving tetrathiomolybdate had adverse effects of anemia and/or leukopenia, and 4 had further transaminase elevations. One patient receiving trientine had an adverse effect of anemia. Four patients receiving trientine died during follow-up, 3 having shown initial neurologic deterioration. Neurologic and speech recovery during a 3-year follow-up period were quite good. CONCLUSION: Tetrathiomolybdate is a better choice than trientine for preserving neurologic function in patients who present with neurologic disease.
Adolescent↗
The use of tetrathiomolybdate in treating fibrotic, inflammatory, and autoimmune diseases, including the non-obese diabetic mouse model.
Tetrathiomolybdate was originally developed for use in Wilson's disease. However, lowering copper levels to below normal levels with tetrathiomolybdate has been found to have efficacy in cancer, probably by turning down signaling by angiogenic cytokines. More recently, we have shown in animals models that tetrathiomolybdate dramatically inhibits pulmonary and liver fibrosis. In other animal models, we have shown that the drug also inhibits liver damage from concanavalin A and acetaminophen, and heart damage from doxorubicin. These studies are briefly reviewed, and we then present data on tetrathiomolybdate's partially protective effect against diabetes in non-obese diabetic mice, an autoimmune model of type I diabetes. Possible mechanisms of tetrathiomolybdate's protective effect are briefly considered.
Animals↗
Comparison of lowering copper levels with tetrathiomolybdate and zinc on mouse tumor and doxorubicin models.
Tetrathiomolybdate (TM), presumably by lowering copper levels and availability, has shown excellent efficacy in animal models of cancer and models of injury that produce fibrotic or inflammatory damage in lung, heart, and liver. Trials in human patients are underway. If the efficacy of TM is indeed through lowering copper levels, other anticopper drugs should be equally efficacious. Zinc is an anticopper drug, with proven efficacy in Wilson's disease, a disease of copper toxicity. In this study, the efficacy of zinc is compared with TM on a mouse tumor model and on the doxorubicin model of heart damage, and it is hypothesized that when copper availability is lowered to an equivalent extent, the 2 drugs would show equivalent efficacy. No effect is found of zinc on inhibiting growth of a tumor that is markedly inhibited by TM, and zinc is found to be less effective than TM in inhibiting cardiac damage from doxorubicin. This study shows that TM's mechanism of action in protecting against doxorubicin toxicity is because of its anticopper effects, as copper supplementation eliminated the protective effect of TM. It is also hypothesized that the differences between TM and zinc may be caused by TM's mechanism of action in which it binds copper already in the body, whereas zinc does not.
Animals↗
Novel therapeutic approaches to the treatment of Wilson's disease.
The treatment of Wilson's disease has changed considerably in recent times, from the use of penicillamine (Cuprimine, Merck) for all stages and types of disease, to the use of three other anticopper drugs at appropriate times for appropriate patients. Each type and stage of the disease can be considered as a therapeutic target, for which specialised therapy is appropriate. This paper systematically reviews the various types and stages of Wilson's disease presentation, and provides opinion on the appropriate therapy for each. For patients presenting with neurological disease, the use of tetrathiomolybdate is optimum; for patients presenting with mild-to-moderate hepatic failure, a combination of trientine (Syprine, Merck) and zinc is recommended, whereas liver transplantation is necessary for those with severe failure; zinc therapy alone or trientine alone as second choice is recommended for patients presenting with hepatitis or cirrhosis without liver failure, for maintenance therapy, for treatment of presymptomatic patients and for treatment of paediatric and pregnant patients.
Chelating Agents↗
Fundamental problems lie ahead in the drug discovery and commercialization process: restructuring of the pharmaceutical industry and an improved partnership with academia are required.
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Academic Medical Centers↗
Anticopper therapy against cancer and diseases of inflammation and fibrosis.
Anticopper drugs that have been developed to treat Wilson's disease, a disease of copper toxicity, include tetrathiomolybdate, zinc, penicillamine, and trientine. Lowering copper levels by a modest amount in non-Wilson's patients with tetrathiomolybdate inhibits angiogenesis, fibrosis and inflammation while avoiding clinical copper deficiency. Through this mechanism tetrathiomolybdate has proven effective in numerous animal models of cancer, retinopathy, fibrosis, and inflammation. Penicillamine has efficacy in rheumatoid arthritis and trientine has efficacy in diabetic neuropathy and diabetic heart disease. If clinical studies support the animal work, anticopper therapy holds promise for therapy of cancer, fibrotic disease and inflammatory and autoimmune diseases.
Animals↗
Tetrathiomolybdate protects against cardiac damage by doxorubicin in mice.
Cardiac toxicity is the limiting factor in therapy with doxorubicin, an otherwise useful cancer drug. In this article we detail our study of a mouse model of doxorubicin-induced cardiac toxicity in which, after 4 days' treatment, doxorubicin caused marked increases in plasma concentrations of creatine kinase, lactic dehydrogenase, and troponin I, indicators of cardiac injury; marked increases in the plasma concentrations of tumor necrosis factor-alpha and interleukin-1(beta), both inflammatory cytokines; and a marked increase in the plasma concentration of interleukin-2, an indicator of cytotoxic T-cell activation. Therapy with tetrathiomolybdate, designed to limit copper availability, eliminated almost all of the increases of these six parameters in plasma. The marked protection against cardiac injury by doxorubicin in tetrathiomolybdate-treated animals suggests that tetrathiomolybdate would be of use clinically in helping prevent doxorubicin toxicity in patients. In other preclinical work, it has been shown that tetrathiomolybdate potentiates the chemotherapeutic effect of doxorubicin in cancer, so a double benefit might accrue clinically from the combined use of tetrathiomolybdate and doxorubicin. The mechanism by which tetrathiomolybdate protects against doxorubicin toxicity is of considerable interest. Our working hypothesis, based on the inhibition of interleukin-2 by tetrathiomolybdate as shown here, is that tetrathiomolybdate interrupts the inflammatory cascade at the activated-T-lymphocyte stage.
Adenosine Triphosphatases↗
Effects of tetrathiomolybdate in a mouse model of retinal neovascularization.
PURPOSE: To determine the effects of tetrathiomolybdate (TM), a copper-chelating agent, on retinal angiogenesis and vascular endothelial growth factor (VEGF) in a mouse model of retinal neovascularization. METHODS: Postnatal day (P)7 C57BL/6N mice were exposed to 75% +/- 2% oxygen for 5 days (P7-P11) and then returned to room air for 5 days (P12-P17) to induce retinal neovascularization. Beginning on P10 or P12, mice received daily intraperitoneal injections of TM or phosphate-buffered saline (PBS; control) through P17. Retinal neovascularization was examined by fluorescein dextran angiography after 5 days in room air and was quantitated histologically by counting the neovascular endothelial cell nuclei anterior to the inner limiting membrane. TM's effects on VEGF expression were measured by ELISA. RESULTS: TM-treated and control animals demonstrated comparable regions of retinal nonperfusion. Retinas from control mice at P17 contained neovascular tufts at the junction between perfused and nonperfused retina. The tufts contained numerous neovascular nuclei. Retinas from mice treated with TM beginning on P10 (2 days before returning to room air), but not P12, demonstrated a 41% reduction in neovascular cell nuclei compared with control mice (P <0.01). The P10-treated mice also demonstrated a 24% reduction of VEGF compared with control animals (P=0.01). CONCLUSIONS: TM significantly inhibits retinal neovascularization and VEGF production in a mouse model of retinal neovascularization.
Angiogenesis Inhibitors↗
Neurologically presenting Wilson's disease: epidemiology, pathophysiology and treatment.
Wilson's disease is a rare autosomal recessive disease of copper accumulation and copper toxicity, due to mutations in the ATP7B gene, which leads to a failure of copper excretion in the bile. It presents clinically primarily as liver disease, psychiatric disease, neurological disease, or a combination of these. The neurological disease is a movement disorder, with abnormalities of speech, tremor, incoordination and dystonia being common features. Diagnosis of neurologically presenting patients is usually straightforward, with Kayser-Fleischer rings and a urine copper over 100 microg/day almost invariably present. In the treatment of neurologically presenting patients, penicillamine should always be avoided, because of the high risk of permanent, drug-induced, additional neurological deterioration. A new drug we have developed, tetrathiomolybdate, given for 8-16 weeks, in combination with zinc, is our first choice for treating these patients. In the absence of availability of tetrathiomolybdate, zinc or trientine are the next best choices.
Behavior↗
Copper lowering therapy with tetrathiomolybdate as an antiangiogenic strategy in cancer.
Tetrathiomolybdate (TM) is a novel anticopper agent under development for use in Wilson's disease. It acts by forming a stable tripartite complex with serum albumin and copper, rendering the complexed copper unavailable for cellular uptake. TM is a very potent anticopper agent and has an excellent safety profile. It has been shown that normal copper levels are required for optimal angiogenesis. Based on this background, we decided to evaluate TM as an anticancer agent. TM treatment of Her/2neu mice, genetically programmed to develop breast cancer, completely prevented the development of visible mammary cancers, although avascular microscopic clusters of cancer cells were present in the breasts of TM treated animals. Controls developed grossly visible tumors. TM was able to strongly inhibit tumor growth in six other rodent models. In a phase 1/2 clinical trial of advanced and metastatic cancers, freedom from progression averaged 11 months, and some individual results were quite dramatic. Eight phase 2 studies of specific cancers have been launched. TM's hypothesized mechanism of action is inhibition of angiogenic cytokines. Unlike other current approaches to antiangiogenic therapy which target single agents, we hypothesize that TM inhibits multiple angiogenic cytokines. Part of this effect appears to stem from inhibition of nuclear factor kappa B (NF(K)B), which in turn controls transcription of many angiogenic and other cytokines. However, there are probably multiple mechanisms, in that some angiogenic cytokines appear to have separate mechanisms of copper dependence. The inhibition of multiple angiogenic cytokines gives TM the potential to be a more global inhibitor of angiogenesis.
Angiogenesis Inhibitors↗
Control of copper status for cancer therapy.
Copper is a trace element which is tightly regulated in mammals and lower animals. Disruptions of copper homeostasis in humans are rare and they cause serious disorders such as Wilson's disease and Menke's disease. Copper plays an important role in promoting physiological and malignant angiogenesis. Formation of new blood vessels by a tumor enables tumor growth, invasion, and metastasis are copper requiring processes. The copper chelator tetrathiomolybdate (TM), which quickly and effectively depletes copper stores, is under investigation as an anti-angiogenic agent. Promising results from in vitro experiments, in pre-clinical animal models, and in a phase I clinical trial have led to several phase II trials of TM in patients with advanced cancers.
Angiogenesis Inhibitors↗
Behavioral abnormalities in Wilson's disease.
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Hepatolenticular Degeneration↗
Wilson's disease: clinical management and therapy.
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Chelating Agents↗
Inhibition of key cytokines by tetrathiomolybdate in the bleomycin model of pulmonary fibrosis.
Tetrathiomolybdate is an anticopper drug with a unique mechanism of action. Tetrathiomolybdate complexes copper to protein and itself, rendering the copper unavailable for cellular uptake. It was originally developed for Wilson's disease, and is now being developed as an antiangiogenic agent for the treatment of cancer. Many angiogenic cytokines require normal levels of copper, and lowered copper levels reduce cytokine signaling while cellular copper requirements are met. Cytokines of fibrosis and inflammation may be similarly copper dependent, since tetrathiomolybdate inhibits bleomycin induced pulmonary inflammation and fibrosis. The basis for this inhibition was evaluated here by examination of tetrathiomolybdate effects on cytokines in lung pathophysiologically important in the bleomycin mouse model of pulmonary damage. Results in mice injected endotracheally with bleomycin confirmed that tetrathiomolybdate therapy was effective in reducing fibrosis. This effect was associated with significant inhibition of bleomycin-induced tumor necrosis factor alpha and transforming growth factor beta expression in lung homogenates. These effects were shown to be independent of one another. This indicates that tetrathiomolybdate therapy can be effective even when fibrosis is at a more chronic stage, wherein inflammatory cytokines are playing a diminishing role. The inhibition of tumor necrosis factor alpha suggests that diseases of tumor necrosis factor alpha overexpression are also potential targets of tetrathiomolybdate therapy.
Administration, Oral↗
Atypical childhood Wilson's disease.
Wilson's disease is a genetic disorder of copper metabolism with a hepatic or neurologic presentation. A hepatic presentation is more common in young children. Neurologic Wilson's disease often manifests as a movement disorder with dystonia, tremor, and dysarthria. Psychiatric or behavioral symptoms can also be a presenting feature of Wilson's disease. We describe an atypical neurologic presentation in a prepubertal child with minimal hepatic involvement; in which transient hemiparesis and encephalopathy dominated her initial neurologic presentation. Brain magnetic resonance imaging revealed extensive cortical and subcortical signal change, in addition to the classical basal ganglia signal abnormality observed in Wilson's disease. She was treated with oral tetrathiomolybdate anticopper therapy, followed by zinc maintenance. Her clinical status and brain imaging improved considerably at 1 year after treatment initiation. Neurologic Wilson's disease may have diverse presentations, and should be considered in children who present with cortical features and signal change on magnetic resonance imaging.
Child↗